## Publications of Robert Calderbank    :recent first  alphabetical  combined listing:

%% Journal articles or Book chapters PUBLISHED
@article{fds235787,
Author = {Calderbank, AR and Wales, DB},
Title = {A global code invariant under the Higman-Sims
group},
Journal = {Journal of Algebra},
Volume = {75},
Number = {1},
Pages = {233-260},
Year = {1982},
ISSN = {0021-8693},
Key = {fds235787}
}

@article{fds235788,
Author = {Calderbank, AR and Mazo, JE and Shapiro, HM},
Title = {UPPER BOUNDS ON THE MINIMUM DISTANCE OF TRELLIS
CODES.},
Journal = {The Bell System technical journal},
Volume = {62},
Number = {8 pt 1},
Pages = {2617-2646},
Year = {1983},
url = {http://dx.doi.org/10.1002/j.1538-7305.1983.tb03197.x},
Abstract = {A trellis code is a 'sliding window' method of encoding a
binary data stream into a sequence of real numbers that are
input to a noisy transmission channel. When a trellis code
is used to encode data at the rate of k bits/channel symbol,
each channel input will depend not only on the most recent
block of k data bits to enter the encoder but will also
depend on, say, the nu bits preceding this block. The
performance of trellis codes, like that of block codes,
depends on a suitably defined minimum-distance property of
the code. This paper obtains upper bounds on this minimum
distance that are simple functions of k and nu . These
results also provide a lower bound on the number of states
required to achieve a specific coding gain.},
Doi = {10.1002/j.1538-7305.1983.tb03197.x},
Key = {fds235788}
}

@article{fds235789,
Author = {Bremner, A and Calderbank, R and Hanlon, P and Morton, P and Wolfskill,
J},
Title = {Two-weight ternary codes and the equation y2 = 4
× 3a + 13},
Journal = {Journal of Number Theory},
Volume = {16},
Number = {2},
Pages = {212-234},
Year = {1983},
ISSN = {0022-314X},
Abstract = {This paper determines the parameters of all two-weight
ternary codes C with the property that the minimum weight in
the dual code C⊥ is at least 4. This yields a
characterization of uniformly packed ternary [n, k, 4]
codes. The proof rests on finding all integer solutions of
the equation y2 = 4 × 3a + 13. © 1983.},
Key = {fds235789}
}

@article{fds236006,
Author = {CALDERBANK, R},
Title = {A SQUARE ROOT BOUND ON THE MINIMUM WEIGHT IN QUASI-CYCLIC
CODES},
Journal = {IEEE Transactions on Information Theory},
Volume = {29},
Number = {3},
Pages = {332-337},
Year = {1983},
Abstract = {The author establishes a square root bound on the minimum
weight in the quasi-cyclic binary codes constructed by V. K.
Bhargava, S. E. Tavares, and S. G. S. Shiva. The proof rests
on viewing the codes as ideas in a group algebra over
GF.},
Key = {fds236006}
}

@article{fds235790,
Author = {Calderbank, AR and Goethals, J-M},
Title = {THREE-WEIGHT CODES AND ASSOCIATION SCHEMES.},
Journal = {Philips Journal of Research},
Volume = {39},
Number = {4-5},
Pages = {143-152},
Year = {1984},
Abstract = {Three-weight projective codes C are considered for which the
restriction to C of the Hamming association scheme H//n(q)
is an association scheme with three classes. Sufficient
conditions are established and restrictions on the three
weights of C are obtained. It is shown in the binary case
that the three-weight subcodes of the shortened second-order
Reed-Muller codes provide a large class of examples,
Previously known examples were the duals of perfect
3-error-correcting or uniformly packed 2-error-correcting
codes.},
Key = {fds235790}
}

@article{fds235791,
Author = {Calderbank, AR and Sloane, NJA},
Title = {NEW FAMILY OF CODES FOR DIAL-UP VOICE LINES.},
Pages = {673-676},
Year = {1984},
Abstract = {Using a certain 4-dimensional lattice, a new family of codes
has been constructed that has a very low error rate. Two
particular codes in this family appear to be excellent
candidates for use in modems operating at 9. 6 and 14. 4
kb/s, respectively, on dial-up voice telephone lines. The
new codes are trellis codes; the output of the encoder is a
4-tuple of odd integers that depends on the input data and
the state of the encoder.},
Key = {fds235791}
}

@article{fds235792,
Author = {Calderbank, R and Wales, DB},
Title = {The Haemers partial geometry and the Steiner system S(5, 8,
24)},
Journal = {Discrete Mathematics},
Volume = {51},
Number = {2},
Pages = {125-136},
Year = {1984},
ISSN = {0012-365X},
url = {http://dx.doi.org/10.1016/0012-365X(84)90066-9},
Abstract = {Haemers has constructed a partial geometry with parameters s
= 4, t = 17, and α = 2, using properties of the
Hoffman-Singleton graph. We describe this geometry in terms
of the Steiner system S(5, 8, 24). © 1984.},
Doi = {10.1016/0012-365X(84)90066-9},
Key = {fds235792}
}

@article{fds235793,
Author = {Calderbank, AR and Chung, FRK and Sturtevant, DG},
Title = {Increasing sequences with nonzero block sums and increasing
paths in edge-ordered graphs},
Journal = {Discrete Mathematics},
Volume = {50},
Number = {C},
Pages = {15-28},
Year = {1984},
ISSN = {0012-365X},
Abstract = {Consider the maximum length f(k) of a (lexicographically)
increasing sequence of vectors in GF(2)k with the property
that the sum of the vectors in any consecutive subsequence
is nonzero modulo 2. We prove that 23 48 · 2k ≤ f(k) ≤
( 1 2 + o(1))2k. A related problem is the following. Suppose
the edges of the complete graph Kn are labelled by the
numbers 1,2,..., (2n). What is the minimum α(n), over all
edge labellings, of the maximum length of a simple path with
increasing edge labels? We prove that α(n) ≤ ( 1 2 +
Key = {fds235793}
}

@article{fds235794,
Author = {Calderbank, AR and Jr, EGC and Flatto, L},
Title = {OPTIMUM HEAD SEPARATION IN A DISK SYSTEM WITH TWO READ/WRITE
Journal = {Journal of the ACM},
Volume = {31},
Number = {4},
Pages = {826-838},
Year = {1984},
url = {http://dx.doi.org/10.1145/1634.1638},
Abstract = {A mathematical model of computer disk storage devices having
are approximated by points in the continuous interval left
bracket 0,1 right bracket , and requests for information on
the disk are processed first-come-first-served. We assume
that the disk heads are maintained a fixed distance d apart;
that is, in procesing a request, both heads are moved the
same distance in the same direction. Assuming that
successive requested locations are independently and
uniformly distributed over left bracket 0,1 right bracket ,
we calculate the invariant measure of a Markov chain
representing successive head positions under the
nearer-server rule: Requests in left bracket 0,d right
bracket are processed by the left head, those in left
bracket 1 minus d, 1 right bracket by the right head, and
those in left bracket d, 1- minus d right bracket by the
nearer of the two heads. Our major objective is the
equilibrium expected distance E(d) that the heads are moved
in processing a request. For the problem of designing the
separation distance d, we show that E (0. 44657) equals 0.
16059 equals min//dE(d). Thus, a basic insight of the
analysis is that a system with two heads performs more than
twice as well as a system with a single head.},
Doi = {10.1145/1634.1638},
Key = {fds235794}
}

@article{fds235795,
Author = {CALDERBANK, R and MAZO, JE},
Title = {A NEW DESCRIPTION OF TRELLIS CODES},
Journal = {IEEE Transactions on Information Theory},
Volume = {30},
Number = {6},
Pages = {784-791},
Year = {1984},
Abstract = {A trellis code is a 'sliding window' method of encoding a
binary data stream as a sequence of real or complex numbers
that are input to a noisy transmission channel. Ungerboeck
has constructed simple trellis codes that provide the same
noise immunity as is given by increasing the power of
uncoded transmission by factors ranging from two to four.
His method is to specify an underlying convolutional code
and a rule (mapping by set partitioning) that maps the
output of this code onto a fixed signal constellation. A new
description of a trellis code is given that combines these
two steps into one. The new description is analytic rather
than graphical. Many practical codes can be described very
simply, and strict bounds on performance can be obtained. A
method for differential encoding trellis codes is presented
that was suggested by the authors' representation.},
Key = {fds235795}
}

@article{fds235796,
Author = {Calderbank, AR and Mazo, JE and Wei, VK},
Title = {ASYMPTOTIC UPPER BOUNDS ON THE MINIMUM DISTANCE OF TRELLIS
CODES.},
Journal = {IEEE Transactions on Communications},
Volume = {COM-33},
Number = {4},
Pages = {305-309},
Year = {1985},
Abstract = {A trellis code is a 'sliding window' method of encoding a
binary data stream as a sequence of signal points. When a
trellis code is used to encode data at the rate of k
bits/channel symbol, each channel input depends not only on
the most recent block of k bits to enter the encoder, but
will also depend on a set of upsilon bits preceding this
block. The upsilon bits determine the state of the encoder
and the most recent block of k bits generates the channel
symbol conditional on the encoder state. The performance of
a trellis code depends on a suitably defined minimum
distance property of that code. This paper obtained upper
bounds on this minimum distance that are better than any
previously known.},
Key = {fds235796}
}

@article{fds235797,
Author = {Calderbank, AR and Coffman, EG and Flatto, L},
Title = {SEQUENCING PROBLEMS IN TWO-SERVER SYSTEMS.},
Journal = {Mathematics of Operations Research},
Volume = {10},
Number = {4},
Pages = {585-598},
Year = {1985},
Abstract = {We analyze a service system in which two identical servers
move one at a time along a linear array of N positions.
Requests for service, each designating one of the N
positions, join a first-in-first queue, where processing of
the nth request does not begin until processing of the
(n-1)th requested is completed. Processing the nth request
entails determining which server to move, moving this server
to the requested position, and then performing the service.
Several potential applications of the model are mentioned,
the most notable being the design of computer storage
systems with multiple access devices. Within a simple
probability model we compare server-selection policies in
terms of the equilibrium expected distance a server is moved
in processing a request. Distance is measured under two
regimes, both assigning a unit distance between adjacent
positions.},
Key = {fds235797}
}

@article{fds235798,
Author = {Calderbank, AR and Sloane, NJA},
Title = {FOUR-DIMENSIONAL MODULATION WITH AN EIGHT-STATE TRELLIS
CODE.},
Journal = {AT&T Technical Journal},
Volume = {64},
Number = {5},
Pages = {1005-1018},
Year = {1985},
Abstract = {A trellis code is a 'sliding window' method for encoding a
binary data stream left brace a**i right brace , a**i equals
0, 1, as a sequence of signal points drawn from R**n. The
rule for assigning signal points depends on the state of the
encoder. In this paper n equals 4, and the signal points are
4-tuples of odd integers. The authors describe an infinite
family of eight-state trellis codes. For k equals 3, 4, 5, .
. . they construct a trellis encoder with a rate of k
bits/four-dimensional signal. They propose that the codes
with rates k equals 8 and 12 be considered for use in modems
designed to achieve data rates of 9. 6 kb/s and 14. 4 kb/s,
respectively.},
Key = {fds235798}
}

@article{fds235799,
Author = {Calderbank, AR and Sloane, NJA},
Title = {EIGHT-DIMENSIONAL TRELLIS CODE.},
Journal = {Proceedings of the IEEE},
Volume = {74},
Number = {5},
Pages = {757-759},
Year = {1986},
Abstract = {A family of eight-state, eight-dimensional trellis codes
based on the E//8 lattice that can be used at 9. 6, 14. 4,
or 19. 2 kb/s is presented. The nominal coding gain is close
to 6 dB. The relatively high path multiplicity of 382 per
dimension can be reduced by increasing the memory of the
code.},
Key = {fds235799}
}

@article{fds236007,
Author = {Calderbank, AR and Heegard, C and Lee, T-A},
Title = {BINARY CONVOLUTIONAL CODES WITH APPLICATION TO MAGNETIC
RECORDING.},
Pages = {42-},
Year = {1986},
Abstract = {Summary form only given. A. R. Calderbank et. al. have
suggested a method of designing codes for channels with
intersymbol interference, such as the magnetic recording
channel. They considered an idealized model of the magnetic
recording channel that leads to the problem of designing
codes for a partial response channel with transfer function
(1 - D**N)/2 where the channel inputs are constrained to be
plus or minus 1. This problem is considered here. Channel
inputs are generated using a nontrivial coset of a binary
convolution code. The coset is chosen to limit the zero-run
length of the output of the channel and so maintain clock
synchronization. The minimum squared Euclidean distance
between outputs corresponding to distinct inputs is bounded
below by the free distance of a second convolutional code
called the magnitude code. An interesting feature of the
analysis is that magnitude codes that are catastrophic may
perform better than those that are noncatastrophic.},
Key = {fds236007}
}

@article{fds236008,
Author = {Calderbank, AR and Hanlon, P},
Title = {The extension to root systems of a theorem on
tournaments},
Journal = {Journal of Combinatorial Theory, Series A},
Volume = {41},
Number = {2},
Pages = {228-245},
Year = {1986},
ISSN = {0097-3165},
Abstract = {M. G. Kendall and B. Babington-Smith proved that if a
tournament p′ is obtained from a tournament p by reversing
the edges of a 3-cycle then p and p′ contain the same
number of 3-cycles. This theorem is the basis of a
cancellation argument used by D. Zeilberer and D. M.
Bressoud in their recent proof of the q-analog of Dyson's
conjecture. The theorem may be restated in terms of the root
system An and the main result of this paper is the extension
of this theorem to arbitrary root systems. As one
application we give a combinatorial proof of a special case
of the Macdonald conjecture for root systems using the
method of Zeilberger and Bressoud. A second application is a
combinatorial proof of the Weyl denominator formula. ©
1986.},
Key = {fds236008}
}

@article{fds236009,
Author = {Calderbank, AR and Sloane, NJA},
Title = {NEW TRELLIS CODES.},
Pages = {59-},
Year = {1986},
Abstract = {Summary form only given. A technique is proposed for
constructing multidimensional trellis codes that provides an
alternative to Ungerboeck's method of 'set partitioning. '
The new codes use a signal constellation consisting of
points from an n-dimensional lattice LAMBDA , with an equal
number of points from each coset of a sublattice LAMBDA
prime . One part of the input stream drives a generalized
convolutional code whose outputs are cosets of LAMBDA prime
, while the other part selects points from these cosets.
This technique allows the path multiplicity to be calculated
easily. It is also possible to describe methods of
differential encoding very simply.},
Key = {fds236009}
}

@article{fds236010,
Author = {Calderbank, AR},
Title = {70,58,5.},
Journal = {IEEE Transactions on Information Theory},
Volume = {IT-32},
Number = {6},
Pages = {828-833},
Year = {1986},
url = {http://dx.doi.org/10.1109/TIT.1986.1057232},
Abstract = {Uniformly packed, linear e-error-correcting codes are
considered. In particular, it is shown that the nonexistence
of a uniformly packed left bracket 70,58,5 right bracket
code C PERPEND is proved by examining geometries associated
with the 3-weight code C.},
Doi = {10.1109/TIT.1986.1057232},
Key = {fds236010}
}

@article{fds236012,
Author = {Brouwer, AE and Calderbank, AR},
Title = {An Erdös-Ko-Rado theorem for regular intersecting families
Journal = {Graphs and Combinatorics},
Volume = {2},
Number = {1},
Pages = {309-316},
Year = {1986},
ISSN = {0911-0119},
url = {http://dx.doi.org/10.1007/BF01788105},
Abstract = {Codewords of weight 8 in the [24, 12] binary Golay code are
called octads. A family ℱ of octads is said to be a
regular intersecting family if ℱ is a 1-design and |x ∩
y| ≠ 0 for all x, y ∈ ℱ. We prove that if ℱ is a
regular intersecting family of octads then |ℱ| ≤ 69.
Equality holds if and only if ℱ is a quasi-symmetric
2-(24, 8, 7) design. We then apply techniques from coding
theory to prove nonexistence of this extremal configuration.
Doi = {10.1007/BF01788105},
Key = {fds236012}
}

@article{fds236013,
Author = {Calderbank, AR and Heegard, C and Lee, T-A},
Title = {BINARY CONVOLUTIONAL CODES WITH APPLICATION TO MAGNETIC
RECORDING.},
Journal = {IEEE Transactions on Information Theory},
Volume = {IT-32},
Number = {6},
Pages = {797-815},
Year = {1986},
url = {http://dx.doi.org/10.1109/TIT.1986.1057245},
Abstract = {Motivated by an idealized model of the magnetic recording
channel, codes were designed for a partial response channel
with transfer function (1-D**N)/2 where the channel inputs
are constrained to be plus or minus 1. Channel inputs are
generated using a nontrivial coset of a binary convolutional
code called the sign code. The probability of decoder error
is determined by the minimum squared Euclidean distance
between outputs corresponding to distinct inputs. This
Euclidean distance is bounded below by the free distance of
a second binary convolutional code called the magnitude
code. The coset of the sign code is chosen to limit the
zero-run length of the output of the channel and so maintain
clock synchronization. The performance of rate k/k plus 1)
codes on the (1-D)/2 and (1-D**2 )/2 channels was analyzed.
It was found that magnitude codes that are catastrophic may
perform better than those that are noncatastrophic.},
Doi = {10.1109/TIT.1986.1057245},
Key = {fds236013}
}

@article{fds326909,
Author = {CALDERBANK, R and KANTOR, WM},
Title = {THE GEOMETRY OF 2-WEIGHT CODES},
Journal = {Bulletin of the London Mathematical Society},
Volume = {18},
Pages = {97-122},
Year = {1986},
Month = {March},
url = {http://dx.doi.org/10.1112/blms/18.2.97},
Doi = {10.1112/blms/18.2.97},
Key = {fds326909}
}

@article{fds236011,
Author = {Calderbank, AR},
Title = {The application of invariant theory to the existence of
quasi-symmetric designs},
Journal = {Journal of Combinatorial Theory, Series A},
Volume = {44},
Number = {1},
Pages = {94-109},
Year = {1987},
ISSN = {0097-3165},
Abstract = {Gleason and Mallows and Sloane characterized the weight
enumerators of maximal self-orthogonal codes with all
weights divisible by 4. We apply these results to obtain a
new necessary condition for the existence of 2 - (v, k, λ)
designs where the intersection numbers s1...,sn satisfy s1
≡ s2 ≡ ... ≡ sn (mod 2). Non-existence of
quasi-symmetric 2-(21, 18, 14), 2-(21, 9, 12), and 2-(35, 7,
3) designs follows directly from the theorem. We also
eliminate quasi-symmetric 2-(33, 9, 6) designs. We prove
that the blocks of quasi-symmetric 2-(19, 9, 16), 2-(20, 10,
18), 2-(20,8, 14), and 2-(22, 8, 12) designs are obtained
from octads and dodecads in the [24, 12] Golay code. Finally
we eliminate quasi-symmetric 2-(19,9, 16) and 2-(22, 8, 12)
Key = {fds236011}
}

@article{fds236015,
Author = {Calderbank, AR and Sloane, NJA},
Title = {NEW TRELLIS CODES BASED ON LATTICES AND COSETS.},
Journal = {IEEE Transactions on Information Theory},
Volume = {IT-33},
Number = {2},
Pages = {177-195},
Year = {1987},
Abstract = {A new technique is proposed for constructing trellis codes,
which provides an alternative to Ungerboeck's method of set
partitioning. The new codes use a signal constellation
consisting of points from an n-dimensional lattice LAMBDA ,
with an equal number of points from each coset of a
sublattice LAMBDA '. One part of the input stream drives a
generalized convolutional code whose outputs are cosets of
LAMBDA ', while the other part selects points from these
cosets. Several of the new codes are better than those
previously known.},
Key = {fds236015}
}

@article{fds236014,
Author = {Calderbank, AR and Sloane, NJA},
Title = {Linear inequalities for covering codes},
Volume = {25 n 13},
Pages = {33-},
Year = {1988},
Abstract = {Summary form only given, as follows. Any code C with
covering radius R must satisfy a set of linear inequalities
that involve the Lloyd polynomial LR(x); these generalize
the sphere bound. The syndrome graphs associated with a
linear code C help to keep track of low weight vectors in
the same coset of C (if there are too many such vectors C
cannot exist). As illustrations it is shown that t[17, 10] =
3 and t[23, 15] = 3, where t[n, k] is the smallest covering
radius of any [n, k] code.},
Key = {fds236014}
}

@article{fds236016,
Author = {Herro, MA and Telang, V and Calderbank, AR},
Title = {Construction of trellis-decodable error-correcting line
codes},
Volume = {25 n 13},
Pages = {63-64},
Year = {1988},
Abstract = {Summary form only given, as follows. The design of balanced
error-correcting codes has received a lot of attention in
recent literature. Besides their error-control capability,
these codes also have power spectral densities that make
them attractive for use on the fiber optic channel and for
data storage on magnetic tape. Since these codes are
balanced, the number of ones in every code word equals the
number of zeros. This property guarantees a null at DC in
the power spectral densities of these codes. The authors
show ways of constructing single error-correcting balanced
codes with dmi n = 4. They construct code words by a
two-layered method. They first define a set of balanced
symbols consisting of a sequence of zeros and ones (with the
number of ones equal to the number of zeros). Thus any
sequence of these symbols will be balanced. The code words
are constructed by concatenating these symbols in a way that
guarantees the minimum distance of the code to be 4, i.e.,
dm in = 4.},
Key = {fds236016}
}

@article{fds236017,
Author = {Calderbank, AR},
Title = {Multi-level trellis codes for the Gaussian channel and for
channels subject to impulsive noise},
Journal = {Proceedings - IEEE Military Communications
Conference},
Volume = {2},
Pages = {673-678},
Year = {1988},
Abstract = {The author designs multilevel trellis codes based on
lattices and cosets that provide greater immunity to
Gaussian noise and/or greater resistance to impulse noise
than previous approaches. He shows how to calculate
minimum-squared distance and path multiplicity in terms of
the norms and multiplicities of the different cosets. The
multilevel structure allows the redundancy in the coset
selection procedure to be allocated efficiently among the
different levels. The proposed codes admit a staged decoding
procedure that requires very few trellis states and has
performance/complexity advantages over maximum-likelihood
decoding.},
Key = {fds236017}
}

@article{fds236018,
Author = {Calderbank, AR and Jr, EGC and Flatto, L},
Title = {OPTIMAL DIRECTORY PLACEMENT ON DISK STORAGE
DEVICES.},
Journal = {Journal of the ACM},
Volume = {35},
Number = {2},
Pages = {433-446},
Year = {1988},
url = {http://dx.doi.org/10.1145/42282.42287},
Abstract = {Two mathematical models dealing with optimal placement of
directories on disk devices are analyzed. Storage addresses
on the disk are approximated by points in the interval left
bracket 0, 1 right bracket . Requests for information on the
disk are represented by a sequence of file names. To process
a request, a read-write head is first moved to a directory
kept on the disk that specifies the address of the file, and
then a head is moved to the specified address. The addresses
are assumed to be independent and uniform on left bracket 0,
1 right bracket . In the first model we consider a system of
two heads separated by a fixed distance d and a directory
situated at 0 less than equivalent to x less than equivalent
to 1. In the second model we consider a system consisting of
one head and n greater than equivalent to 2 directories at 0
less than equivalent to x//1 less than x//2 less than . . .
less than x//n less than equivalent to 1. For both models we
study the problem of finding those values of the parameters
that minimize the expected head motion to process a request
in statistical equilibrium.},
Doi = {10.1145/42282.42287},
Key = {fds236018}
}

@article{fds236019,
Author = {Calderbank, AR},
Title = {Geometric invariants for quasi-symmetric
designs},
Journal = {Journal of Combinatorial Theory, Series A},
Volume = {47},
Number = {1},
Pages = {101-110},
Year = {1988},
ISSN = {0097-3165},
Abstract = {Let p be an odd prime. We derive new necessary conditions
for the existence of 2 - (ν, k, λ) designs where the block
intersection sizes s1, s2, ..., sn satisfy s1 ≡ s2 ≡ ...
≡ sn (mod p). The method is to define a nondegenerate
scalar product on a 2m-dimensional vector space and to
construct an m-dimensional totally singular subspace. This
result is a generalization to nonsymmetric designs of the
Bruck-Ryser-Chowla theorem. © 1988.},
Key = {fds236019}
}

@article{fds236020,
Author = {Jr, GDF and Calderbank, AR},
Title = {COSET codes for partial response; or, codes with spectral
nulls},
Volume = {25 n 13},
Pages = {141-},
Year = {1988},
Abstract = {Summary form only given, as follows. Known coset codes are
adapted for use on partial response channels or to generate
signals with spectral nulls. By use of methods of coset
precoding and running digital sum feedback, any desired
tradeoff can be achieved between the power and spectra of
the relevant sequences, up to the optimum tradeoff possible.
A fundamental theorem specifying this optimum tradeoff is
given. An MLSE decoder for the original code may be used for
the adapted code, and such a decoder then attains the
minimum squared distance of the original code. These methods
sometimes generate codes with greater minimum squared
distance than that of the original code, which can be
attained by augmented decoders, although such decoders
inherently require long decoding delays and may be subject
to quasi-catastrophic error propagation. The general
conclusion is that, at least for sequences that support
large number of bits per symbol, one can obtain the same
kinds of performance and complexity on partial response
channels, or for sequences with spectral nulls, as can be
obtained with the same coset codes in the ordinary
memoryless case.},
Key = {fds236020}
}

@article{fds236021,
Author = {Pottie, GJ and Taylor, DP and Calderbank, AR},
Title = {Multi-level channel codes based on partitioning},
Volume = {25 n 13},
Pages = {166-},
Year = {1988},
Abstract = {Summary form only given, as follows. Imai and Hirakawa have
proposed a multilevel coding method based on binary block
codes that admits a staged decoding procedure. This method
has been extended to the design of codes for the Gaussian
channel by Ginzburg and Tanner. The authors show that coset
codes (including lattice, Ungerboeck, and binary codes) and
indeed any codes which rely on a partitioning of the signal
set may be described by one formalism, and all can be used
in a multilevel scheme. The combination of such codes in a
multilevel scheme often leads to reduced decoding complexity
for the same performance as previously published schemes.
The authors discuss some alternatives to the staged decoding
structure, and the tradeoffs involved. They present as
examples powerful multi-level schemes for the Gaussian
channel and for channels that are subject to both Gaussian
and impulsive noise.},
Key = {fds236021}
}

@article{fds236022,
Author = {Calderbank, AR},
Title = {Inequalities for quasi-symmetric designs},
Journal = {Journal of Combinatorial Theory, Series A},
Volume = {48},
Number = {1},
Pages = {53-64},
Year = {1988},
ISSN = {0097-3165},
Abstract = {A 2-design is said to be quasi-symmetric if there are two
block intersection sizes. We obtain inequalities satisfied
by the parameters of a quasi-symmetric design using linear
programming techniques. The same methods apply to codes with
covering radius 2 with the property that the number of
codewords at distance 2 from a given vector ν depends on
the distance of ν from the code. © 1988.},
Key = {fds236022}
}

@article{fds236023,
Author = {Calderbank, AR and Lee, T-A and Mazo, JE},
Title = {Baseband trellis codes with a spectral null at
zero},
Journal = {IEEE Transactions on Information Theory},
Volume = {34},
Number = {3},
Pages = {425-434},
Year = {1988},
url = {http://dx.doi.org/10.1109/18.6023},
Abstract = {A method is described for modifying classical N-dimensional
trellis codes to provide baseband codes that combine a
spectral null at DC with significant coding gain. The
information rate of the classical code is decreased by one
bit, and this extra redundancy is used to keep the running
digital sum bounded. Equivalently, if the rate is held
constant, then twice as many signal points are needed,
causing a power penalty of 6/N dB. Baseband trellis codes
are presented for several information rates together with
complete spectral plots and performance comparisons. A
method of constructing baseband codes with multiple spectral
nulls is also described.},
Doi = {10.1109/18.6023},
Key = {fds236023}
}

@article{fds236026,
Author = {Calderbank, AR and Sloane, NJA},
Title = {Inequalities for covering codes},
Journal = {IEEE Transactions on Information Theory},
Volume = {34},
Number = {5 pt 2},
Pages = {1276-1280},
Year = {1988},
url = {http://dx.doi.org/10.1109/18.21257},
Abstract = {Any code C with covering radius R must satisfy a set of
linear inequalities that involve the Lloyd polynomial LR(x);
these generalize the sphere bound. Syndrome graphs
associated with a linear code C are introduced to help keep
track of low-weight vectors in the same coset of C (if there
are too many such vectors C cannot exist). As illustrations
it is shown that t[17,10]=3 nd t[23,15]=3 where t[n,k] is
the smallest covering radius of any [n,k]
code.},
Doi = {10.1109/18.21257},
Key = {fds236026}
}

@article{fds236024,
Author = {Calderbank, AR and Herro, MA and Telang, V},
Title = {Multilevel approach to the design of DC-free line
codes},
Journal = {IEEE Transactions on Information Theory},
Volume = {35},
Number = {3},
Pages = {579-583},
Year = {1989},
url = {http://dx.doi.org/10.1109/18.30980},
Abstract = {A multilevel approach to the design of DC-free line codes is
presented. The different levels can be used for different
purposes, for example, to control the maximum accumulated
charge or to guarantee a certain minimum distance. The
advantages of codes designed by this method over similar
codes are the improved run-length/accumulated-charge
parameters, higher transmission rate, and the systematic
nature of the code construction. The multilevel structure
allows the redundancy in the signal selection procedure to
be allocated efficiently among the different levels. It also
allows the use of suboptimal staged decoding procedures that
have performance/complexity advantages over
maximum-likelihood decoding.},
Doi = {10.1109/18.30980},
Key = {fds236024}
}

@article{fds236025,
Author = {Calderbank, AR},
Title = {Multilevel codes and multistage decoding.},
Journal = {IEEE Transactions on Communications},
Volume = {37},
Number = {3},
Pages = {222-229},
Year = {1989},
Abstract = {H. Imai and S. Hirakawa have proposed (1977) a multilevel
coding method based on binary block codes that admits a
staged decoding procedure. Here the coding method is
extended to coset codes and it is shown how to calculate
minimum squared distance and path multiplicity in terms of
the norms and multiplicities of the different cosets. The
multilevel structure allows the redundancy in the coset
selection procedure to be allocated efficiently among the
different levels. It also allows the use of suboptimal
multistage decoding procedures that have
performance/complexity advantages over maximum-likelihood
decoding.},
Key = {fds236025}
}

@article{fds236027,
Author = {Jr, GDF and Calderbank, AR},
Title = {Coset codes for partial response channels; or, coset codes
with spectral nulls},
Journal = {IEEE Transactions on Information Theory},
Volume = {35},
Number = {5},
Pages = {925-943},
Year = {1989},
url = {http://dx.doi.org/10.1109/18.42211},
Abstract = {Known coset codes are adapted for use on partial response
channels or to generate signals with spectral nulls. By
using coset precoding and running digital sum feedback, any
desired tradeoff can be achieved between the power and
spectra of the relevant sequences, up to the optimum
tradeoff possible. A fundamental theorem specifying this
optimum tradeoff is given. A maximum-likelihood-sequence-estimation
(MLSE) decoder for the original code may be used for the
adapted code, and such a decoder then attains the minimum
squared distance of the original code. These methods
sometimes generate codes with greater minimum squared
distance than that of the original code; this distance can
be attained by augmented decoders, although such decoders
inherently require long decoding delays and may be subjected
to quasi-catastrophic error propagation. The authors
conclude that, at least for sequences supporting large
numbers of bits per symbol, coset codes can be adapted to
achieve effectively the same performance and complexity on
partial response channels, or for sequences with spectral
nulls, as they do in the ordinary memoryless
case.},
Doi = {10.1109/18.42211},
Key = {fds236027}
}

@article{fds236028,
Author = {Calderbank, AR and Mazo, JE},
Title = {Baseband line codes via spectral factorization.},
Journal = {IEEE Journal on Selected Areas in Communications},
Volume = {7},
Number = {6},
Pages = {914-928},
Year = {1989},
url = {http://dx.doi.org/10.1109/49.29614},
Abstract = {A description is given of a methodology for designing
baseband line codes with prescribed spectral nulls in the
transmitted spectrum. These codes have the property that the
transmitted power is adjustable (with a concomitant change
in spectral shape, i.e., null width) and can be made
arbitrarily close to the innovations power, while keeping
the minimum distance between signal points (or sequences)
constant. The essential design step requires the spectral
factorization of a certain trigonometric polynomial. The
line code that results can easily be used in conjunction
with a large class of trellis-coded modulation schemes.
Specific baseband codes are constructed using a
representation of the general theory that involves a dither
variable, which is used to create integer symbols and to
minimize the size of the symbol alphabet. Emphasis is on the
design of line codes with a double null at DC using the
symbol alphabet {±1, ±3}.},
Doi = {10.1109/49.29614},
Key = {fds236028}
}

@article{fds236031,
Author = {Calderbank, AR and Jr, EGC and Flatto, L},
Title = {Note extending the analysis of two-head disk systems to more
general seek-time characteristics},
Journal = {IEEE Transactions on Computers},
Volume = {38},
Number = {11},
Pages = {1584-1586},
Year = {1989},
url = {http://dx.doi.org/10.1109/12.42130},
Abstract = {The authors analyze a model of a movable-head disk system
with two read/write heads maintained a fixed distance d
apart on each arm. Successive request-addresses are assumed
to be independent random variables, uniformly distributed
over the set of cylinders. The purpose of the analysis is to
find that value of d which minimizes the expected seek time
per request, assuming that seek time varies linearly with
the distance z traveled by the heads. The authors extend an
earlier analysis of this model to more general seek-time
characteristics which take into account nonlinear
acceleration effects. Detailed results, combining both
analysis and simulation experiments, are presented for seek
times linear in zα, 0 ≤ α ≤ 1. An unexpected result of
the study was that the value of d which minimizes expected
seek time is very nearly independent of α.},
Doi = {10.1109/12.42130},
Key = {fds236031}
}

@article{fds235800,
Author = {Calderbank, AR},
Title = {Covering radius and the chromatic number of Kneser
graphs},
Journal = {Journal of Combinatorial Theory, Series A},
Volume = {54},
Number = {1},
Pages = {129-131},
Year = {1990},
ISSN = {0097-3165},
url = {http://dx.doi.org/10.1016/0097-3165(90)90011-K},
Abstract = {Let C be a binary linear code with covering radius R and let
C0 be a subcode of C with codimension i. We prove that the
covering radius R0 of C satisfies R0 ≤ 2R + 2i - 1, by
setting up a graph coloring problem involving Kneser graphs.
Doi = {10.1016/0097-3165(90)90011-K},
Key = {fds235800}
}

@article{fds235801,
Author = {Calderbank, AR and Ozarow, LH},
Title = {Nonequiprobable signaling on the Gaussian
channel},
Journal = {IEEE Transactions on Information Theory},
Volume = {36},
Number = {4},
Pages = {726-740},
Year = {1990},
url = {http://dx.doi.org/10.1109/18.53734},
Abstract = {Signaling schemes for the Gaussian channel based on
finite-dimensional lattices are considered. The signal
constellation consists of all lattice points within a region
R, and the shape of this region determines the average
signal power. Spherical signal constellations minimize
average signal power, and in the limit as N → ∞, the
shape gain of the N-sphere over the N-cube approaches πe/6
≈ 1.53 dB. A nonequiprobable signaling scheme is described
that approaches this full asymptotic shape gain in any fixed
dimension. A signal constellation Ω is partitioned into T
subconstellations Ω0,..., ΩT-1 of equal size by scaling a
basic region R. Signal points in the same subconstellation
are used equiprobably, and a shaping code selects the
subconstellation Ωi with frequency fi. Shaping codes make
it possible to achieve any desired fractional bit rate. The
schemes presented are compared with equiprobable signaling
schemes based on Voronoi regions of multidimensional
lattices. For comparable shape gain and constellation
expansion ratio, the peak to average power ratio of the
schemes presented is superior. Furthermore, a simple table
lookup is all that is required to address points in the
constellations. This is not the case for Voronoi
constellations. It is also shown that it is possible to
integrate coding and nonequiprobable signaling within a
common multilevel framework.},
Doi = {10.1109/18.53734},
Key = {fds235801}
}

@article{fds235804,
Author = {Calderbank, AR and Frankl, P},
Title = {Binary codes and quasi-symmetric designs},
Journal = {Discrete Mathematics},
Volume = {83},
Number = {2-3},
Pages = {201-204},
Year = {1990},
ISSN = {0012-365X},
Abstract = {We obtain a new necessary condition for the existence of a
2-(υ, k, λ) design where the block intersection sizes
s1,s2,...,sn satisfy s1≡s2≡...≡sn≡s( mod 2). This
condition eliminates quasi-symmetric 2-(20, 10, 18) and
2-(60, 30, 58) designs. Quasi-symmetric 2- (20, 8, 14)
designs are eliminated by an ad hoc coding theoretic
Key = {fds235804}
}

@article{fds236029,
Author = {Calderbank, AR and Ozarow, LH},
Title = {Non-equiprobable signaling on the Gaussian
channel},
Pages = {145-},
Year = {1990},
Abstract = {Summary form only given, as follows. Many signaling schemes
for the Gaussian channel are based on finite-dimensional
lattices. The signal constellation consists of all lattice
points within a region R, and the shape of this region
determines the average signal power. In the limit as N →
∞, the shape gain the N-sphere over the N-cube approaches
πe/6 = 1.53 dB. It is shown that the full asymptotic shape
gain can be realized in any fixed dimension by
nonequiprobable signaling. Shaping schemes that achieve a
significant fraction of the available asymptotic shaping
gain are described. The peak-to-average-power ratio of these
schemes is superior to that of equiprobable signaling
schemes based on Voronoi regions of multidimensional
lattices. The new shaping schemes admit a simple staged
demodulation procedure.},
Key = {fds236029}
}

@article{fds236030,
Author = {Calderbank, AR and Delsarte, P and Sloane, NJA},
Title = {A strengthening of the Assmus-Mattson Theorem},
Pages = {41-},
Year = {1990},
Abstract = {Summary form only given. Let w1 = d, w2, ..., ws be the
weights of the nonzero code words in a binary linear [n, k,
d] code C, and let w1′, w2′, ..., ws′ be the nonzero
weights in the dual code C⊥. Let t be an integer in the
range 0 &lt; t &lt; d such that there are at most d - t
weights wi′ with 0 &lt; wi′ ≤ n - t. Assmus and
Mattson proved that the words of any weight wi in C form a
t-design. Let δ = 0 or 1, according to whether C is even or
not, and let B denote the set of code words of weight d. The
present authors have proved that if w2 ≥ d + 4, then
either (1) t = 1, d is odd, and B partitions {1, 2, ..., n},
or (2) B is a (t + δ + 1)-design, or (3) B is a {1, ..., t
+ δ, t + δ + 2}-design. If C is a self-orthogonal binary
code with all weights divisible by 4, then the result
extends to code words of any given weight. The special case
of code words of minimal weight in extremal self-dual codes
also follows from a theorem of Venkov and
Koch.},
Key = {fds236030}
}

@article{fds235802,
Author = {Calderbank, AR and Delsarte, P and Sloane, NJA},
Title = {A strengthening of the Assmus-Mattson theorem},
Journal = {IEEE Transactions on Information Theory},
Volume = {37},
Number = {5},
Pages = {1261-1268},
Year = {1991},
url = {http://dx.doi.org/10.1109/18.133244},
Abstract = {Let w1 = d,w2,...,ws be the weights of the nonzero codewords
in a binary linear [n,k,d] code C, and let w′1, w′2,
..., w′s′, be the nonzero weights in the dual code C⊥.
Let t be an integer in the range 0 &lt; t &lt; d such that
there are at most d - t weights w′i with 0 &lt; w′i ≤
n - t. E. F. Assmus and H. F. Mattson, Jr. (1969) proved
that the words of any weight wi in C form a t-design. The
authors show that if w2 ≥ d + 4 then either the words of
any nonzero weight wi form a (t + 1)-design or else the
codewords of minimal weight d form a {1,2,...,t,t +
2}-design. If in addition C is self-dual with all weights
divisible by 4 then the codewords of any given weight wi
form either a (t + 1)-design or a {1,2,...,t,t + 2}-design.
The proof avoids the use of modular forms.},
Doi = {10.1109/18.133244},
Key = {fds235802}
}

@article{fds235803,
Author = {Calderbank, AR},
Title = {The mathematics of moderns},
Journal = {The Mathematical Intelligencer},
Volume = {13},
Number = {3},
Pages = {56-65},
Year = {1991},
ISSN = {0343-6993},
url = {http://dx.doi.org/10.1007/BF03023836},
Doi = {10.1007/BF03023836},
Key = {fds235803}
}

@article{fds235805,
Author = {Calderbank, AR and Mazo, JE},
Title = {Spectral nulls and coding with large alphabets},
Journal = {IEEE Communications Magazine},
Volume = {29},
Number = {12},
Pages = {58-67},
Year = {1991},
url = {http://dx.doi.org/10.1109/35.120352},
Abstract = {Generalizations of the simple alternate-mark-inversion (AMI)
line code that provide enhanced immunity to additive noise
as well as spectral shaping are considered. The first
technique is the extension of balanced disparity methods to
multilevel signaling alphabets. This is a small step beyond
simple codes such as AMI that are used to transmit binary
PCM over twisted-pair cables. An important feature of this
method (and later methods) is the use of suboptimal
decoders. The most sophisticated technique used was
Tomlinson filtering, and here it was possible to require a
spectral null in the line code spectrum with a certain
minimum width, and to minimize line code power subject to
this requirement. This technique is compared to methods
introduced by B. H. Marcus and P. H. Siegel (1987) in
magnetic recording that provide spectral nulls at rational
multiples of the symbol frequency. Theoretical
possibilities, rather than techniques proven superior for a
particular application, are addressed.},
Doi = {10.1109/35.120352},
Key = {fds235805}
}

@article{fds235806,
Author = {Calderbank, AR and Klimesh, M},
Title = {Balanced codes and nonequiprobable signaling},
Journal = {IEEE Transactions on Information Theory},
Volume = {38},
Number = {3},
Pages = {1119-1122},
Year = {1992},
url = {http://dx.doi.org/10.1109/18.135651},
Abstract = {The problem of shaping signal constellations that are
designed for the Gaussian channel is considered. The signal
constellation consists of all points from some translate of
a lattice Λ that lie within a region R. The signal
constellation is partitioned into T annular
subconstellations Ω0,...,ΩT-1 by scaling the region R.
Signal points in the same subconstellation are used
equiprobably, and a shaping code selects region Ωi with
frequency fi. If the signal constellation is partitioned
into annular subconstellations of unequal size, then the
transmission rate should vary with the choice of codeword in
the shaping code, and it will be necessary to queue the data
in buffers. It is described how the balanced binary codes
constructed by D. E. Knuth (1986) can be used to avoid a
data rate that is probabilistic. The basic idea is that if
symbols 0 and 1 represent constellations of unequal size,
and if all shaping codewords have equally many 0's and 1's,
then the data rate will be deterministic.},
Doi = {10.1109/18.135651},
Key = {fds235806}
}

@article{fds235807,
Author = {Calderbank, AR},
Title = {Covering bounds for codes},
Journal = {Journal of Combinatorial Theory, Series A},
Volume = {60},
Number = {1},
Pages = {117-122},
Year = {1992},
ISSN = {0097-3165},
Abstract = {Given an [n, k]R code C, and a subcode H of C with
codimension j, define SHj(C) = maxx∈F2n {d(x, H) + d(x, C
H)}, and define the j-norm, Sj(C) to be the minimum value of
SHj(C) as H ranges over the subcodes with codimension j. We
prove that if k (n + 1) &gt; R (R + 1), then S1(C) ≤ 2R +
Key = {fds235807}
}

@article{fds235808,
Author = {Blokhuis, A and Calderbank, AR},
Title = {Quasi-symmetric designs and the Smith Normal
Form},
Journal = {Designs, Codes and Cryptography},
Volume = {2},
Number = {2},
Pages = {189-206},
Year = {1992},
ISSN = {0925-1022},
url = {http://dx.doi.org/10.1007/BF00124897},
Abstract = {We obtain necessary conditions for the existence of a 2 -
(ν, k, λ) design, for which the block intersection sizes
s1, s2, ..., snsatisfy s1 ≡ s2 ≡ ... ≡ sn ≡ s (mod
pe),where p is a prime and the exponent e is odd. These
conditions are obtained from restriction on the Smith Normal
Form of the incidence matrix of the design. We also obtain
restrictions on the action of the automorphism group of a 2
- (ν, k, λ) design on points and on blocks. © 1992 Kluwer
Doi = {10.1007/BF00124897},
Key = {fds235808}
}

@article{fds236032,
Author = {Calderbank, AR and Pottie, GJ},
Title = {Upper bounds for small trellis codes},
Journal = {IEEE Transactions on Information Theory},
Volume = {38},
Number = {6},
Pages = {1791-1795},
Year = {1992},
url = {http://dx.doi.org/10.1109/18.165452},
Abstract = {An upper bound on the minimum squared distance of trellis
codes by packing Voronoi cells is derived and compared with
previously known bounds. The authors focus on codes with
small memory for modulation formats such as pulse amplitude
modulation (PAM), m-ary quadrature amplitude modulation
(QAM), and m-ary phase shift keying (PSK). The bound is
tight to search results for coset codes with a small number
of states.},
Doi = {10.1109/18.165452},
Key = {fds236032}
}

@article{fds236033,
Author = {Calderbank, AR},
Title = {Covering machines},
Journal = {Discrete Mathematics},
Volume = {106-107},
Number = {C},
Pages = {105-110},
Year = {1992},
ISSN = {0012-365X},
Abstract = {We construct 2-state covering machines from binary linear
codes with a sufficiently rich subcode structure. The goal
is to trade multiple covering properties for increased
redundancy. We explain why the expected covering properties
of covering machines should be superior to those of codes
obtained by iterating the ADS construction. ©
1992.},
Key = {fds236033}
}

@article{fds235809,
Author = {Calderbank, AR and Fishburn, PC},
Title = {Normalized second moment of the binary lattice determined by
a convolutional code},
Journal = {Proceedings of the 1993 IEEE International Symposium on
Information Theory},
Pages = {137-},
Year = {1993},
Abstract = {The output of a finite state machine is a collection of
codewords that can be searched efficiently to find the
optimum codeword with respect to any nonnegative measure
that can be calculated on a symbol by symbol basis.
Applications involving trellis codes are considered.
Although details are given for the convolutional code, the
method can be applied to arbitrary codes.},
Key = {fds235809}
}

@article{fds235810,
Author = {Calderbank, AR and Georghiades, CN},
Title = {Coding for the unsynchronized optical OPPM
channel},
Journal = {Proceedings of the 1993 IEEE International Conference on
Communications},
Pages = {557-561},
Year = {1993},
Abstract = {Random OPPM sequences result in an unrecoverable error floor
on both the probability of erroneous synchronization and the
probability of symbol error when only chip synchronization
is present. It is known, however, that for a given sequence
length M, a subset of the set of all possible sequences is
synchronizable in the sense that in the absence of noise,
the receiver can correctly symbol-synchronize by observing M
or more symbol intervals. In this paper we design finite
state machines and codes over a J-ary alphabet which produce
sequences with the property that every subsequence of length
L is synchronizable and introduce algorithms that utilize
the memory in the encoded sequences to produce joint
estimates of timing and sequences.},
Key = {fds235810}
}

@article{fds235811,
Author = {Calderbank, AR and Fishburn, PC and Rabinovich,
A},
Title = {Covering properties of convolutional codes and associated
lattices},
Journal = {Proceedings of the 1993 IEEE International Symposium on
Information Theory},
Pages = {141-},
Year = {1993},
Abstract = {This talk describes methods for analyzing the expected and
worst-case performance of sequence based methods of
quantization. We suppose that the quantization algorithm is
dynamic programming, where the current step depends on a
vector of path metrics, which we call a metric function. Our
principal objective is a concise representation of these
metric functions and the possible trajectories of the
dynamic programming algorithm. We shall consider
quantization of equiprobable binary data using a
convolutional code. Here the additive group of the code
splits the set of metric functions into a finite collection
of subsets. The subsets form the vertices of a directed
graph, where edges are labelled by aggregate incremental
increases in mean squared error (msc). Paths in this graph
correspond both to trajectories of the Viterbi algorithm,
and to cosets of the code. For the rate 1/2 convolutional
code [1 + D2, 1 + D + D2], this graph has only 9 vertices.
In this case it is particularly simple to calculate per
dimension expected and worst case mse, and performance is
similar to the binary [24, 12] Colay code. Our methods also
apply to quantization of arbitrary sysmmetric probability
distributions on [0, 1] using convolutional codes. For the
uniform distribution on [0, 1], the expected mse is the
second moment of the 'Voronoi region' of an infinite
dimensional lattice determined by the convolutional code. It
may also be interpreted as an increase in the reliability of
a transmission scheme obtained by nonequiprobable
signalling. For certain convolutional codes we obtain a
formula for expected mse that depends only on the
distribution of differences for a single pair of path
metrics.},
Key = {fds235811}
}

@article{fds235812,
Author = {Calderbank, AR and Seshadri, N},
Title = {Multilevel codes for unequal error protection},
Journal = {Proceedings of the 1993 IEEE International Symposium on
Information Theory},
Pages = {183-},
Year = {1993},
Abstract = {In many speech and image coding schemes, some of the coded
bits are extremely sensitive to channel errors while some
others exhibit very little sensitivity. In order to make the
best use of channel redundancy, unequal error protection
(UEP) codes are needed. In a bandlimited environment, such
coding and the modulation should be integrated. In this
paper, the authors propose two combined UEP coding and
modulation schemes.},
Key = {fds235812}
}

@article{fds235813,
Author = {Calderbank, AR and Graham, RL and Shepp, LA and Frank, P and Li,
W-CW},
Title = {Sperner capacity of linear and nonlinear codes for the
cyclic triangle},
Journal = {Proceedings of the 1993 IEEE International Symposium on
Information Theory},
Pages = {154-},
Year = {1993},
Abstract = {Shannon introduced the concept of zero-error capacity of a
discrete memoryless channel. The channel determines an
undirected graph on the symbol alphabet, where adjacency
means that symbols cannot be confused at the receiver. The
zero-error or Shannon capacity is an invariant of this
graph. Gargano, Koerner, and Vaccaro have recently extended
the concept of Shannon capacity to directed graphs. Their
generalization of Shannon capacity is called Sperner
capacity. We resolve a problem posed by these authors by
giving the first example (the two orientations of the
triangle) of a graph where the Sperner capacity depends on
the orientations of the edges. Sperner capacity seems to be
achieved by nonlinear codes, whereas Shannon capacity seems
to be attainable by linear codes. In particular, linear
codes do not achieve Sperner capacity for the cyclic
triangle. We use Fourier analysis or linear programming to
obtain the best upper bounds for linear codes. The bound for
unrestricted codes are obtained from rank arguments,
eigenvalue interlacing inequalities and polynomial algebra.
The statement of the cyclic q-gon problem is very simple:
what is the maximum size Nq(n) of a subset Sn of {0, 1, ...,
q - 1}n with the property that for every pair of distinct
vectors x = (xi), y = (yi) member of Sn, we have xj - yj ≡
1(mod q) for some j? For q = 3 (the cyclic triangle), we
show N3(n) ≅ 2n. If however Sn is a subgroup, then we give
a simple proof that |Sn| ≤ √3n.},
Key = {fds235813}
}

@article{fds235814,
Author = {Pottie, GJ and Calderbank, AR},
Title = {Further asymptotic upper bounds on the minimum distance of
trellis codes},
Journal = {IEEE Transactions on Information Theory},
Volume = {39},
Number = {4},
Pages = {1428-1434},
Year = {1993},
url = {http://dx.doi.org/10.1109/18.243464},
Abstract = {Asymptotic upper bounds on the minimum distance of trellis
codes are derived. A universal bound and bounds specific to
PSK and QAM signal sets are obtained.},
Doi = {10.1109/18.243464},
Key = {fds235814}
}

@article{fds235815,
Author = {Calderbank, AR and Seshadri, N},
Title = {Multilevel codes for unequal error protection},
Journal = {IEEE Transactions on Information Theory},
Volume = {39},
Number = {4},
Pages = {1234-1248},
Year = {1993},
url = {http://dx.doi.org/10.1109/18.243441},
Abstract = {In many speech and image coding schemes, some of the coded
bits are extremely sensitive to channel errors while some
others exhibit very little sensitivity. In order to make the
best use of channel redundancy, unequal error protection
(UEP) codes are needed. In a bandlimited environment, such
coding and the modulation should be integrated. Two combined
UEP coding and modulation schemes are proposed. The first
method multiplexes different coded signal constellations,
with each coded constellation providing a different level of
error protection. The novelty here is that a codeword
specifies the multiplexing rule and the choice of the
codeword from a fixed codebook is used to convey additional
important information. The decoder determines the
multiplexing rule before decoding the rest of the data. The
second method is based on partitioning a signal
constellation into disjoint subsets, where the most
important data sequence is encoded, using most of the
available redundancy, to specify a sequence of subsets. The
partitioning and code construction is done to maximize the
minimum Euclidean distance between two different valid
subset sequences. This leads to novel ways of partitioning
the signal constellations into subsets. Finally, the less
important data selects a sequence of signal points to be
transmitted from the subsets. A side benefit of the proposed
set partitioning procedure is a reduction in the number of
nearest neighbors, sometimes even over the uncoded signal
constellation. Many of the codes designed provided virtually
error free transmission (greater than 6-dB coding gain) for
some fraction (for example, 25%) of the data while providing
a coding gain of 1-2 dB for the remaining data with respect
to uncoded transmission. The two methods can also be
combined to realize new coded signal constellations for
unequal error protection.},
Doi = {10.1109/18.243441},
Key = {fds235815}
}

@article{fds236034,
Author = {Pottie, GJ and Calderbank, AR},
Title = {Channel coding strategies for cellular radio},
Journal = {Proceedings of the 1993 IEEE International Symposium on
Information Theory},
Pages = {251-},
Year = {1993},
Abstract = {To improve re-use of time/frequency slots in a cellular
radio system, it is desirable for the average interference
levels seen by all users to be made approximately equal. We
provide constructions based on orthogonal Latin squares that
guarantee different sets of users to interfere in successive
slots. We illustrate how this may be combined with
convolutional coding to provide large performance
improvement with low delay in a slow hopped
system.},
Key = {fds236034}
}

@article{fds235816,
Author = {Calderbank, AR and Fishburn, PC},
Title = {Normalized second moment of the binary lattice determined by
a convolutional code},
Journal = {IEEE Transactions on Information Theory},
Volume = {40},
Number = {1},
Pages = {166-174},
Year = {1994},
url = {http://dx.doi.org/10.1109/18.272475},
Abstract = {We calculate the per-dimension mean squared error μ(S) of
the two-state convolutional code C with generator matrix
[1,1+D], for the symmetric binary source S = {0,1}, and for
the uniform source S = [0,1]. When S = {0,1}, the quantity
μ(S) is the second moment of the coset weight distribution,
which gives the expected Hamming distance of a random binary
sequence from the code. When S = [0,1], the quantity μ(S)
is the second moment of the Voronoi region of the modulo 2
binary lattice determined by C. The key observation is that
a convolutional code with 2v states gives 2v approximations
to a given source sequence, and these approximations do not
differ very much. It is possible to calculate the steady
state distribution for the differences in these path
metrics, and hence, the second moment. In this paper we
shall only give details for the convolutional code [1,1+D],
but the method applies to arbitrary codes. We also define
the covering radius of a convolutional code, and calculate
this quantity for the code [1,1+D].},
Doi = {10.1109/18.272475},
Key = {fds235816}
}

@article{fds235817,
Author = {Kumar, PV and Helleseth, T and Calderbank, AR and Jr,
ARH},
Title = {Large families of quaternary sequences with low
correlation},
Journal = {IEEE International Symposium on Information Theory -
Proceedings},
Year = {1994},
Abstract = {A nested chain of quaternary-sequence families having low
correlation values is presented. The families are suitable
for application in CDMA systems employing QPSK
modulation.},
Key = {fds235817}
}

@article{fds235818,
Author = {Kumar, PV and Helleseth, T and Calderbank, AR},
Title = {Upper bound for some exponential sums over Galois rings and
applications},
Journal = {IEEE International Symposium on Information Theory -
Proceedings},
Year = {1994},
Abstract = {An upper bound for Weil-type exponential sums over Galois
rings is presented together with some examples where the
bound is tight. The bound may be regarded as the Galois-ring
analogue of the well-known Weil-Carlitz-Uchiyama bound for
exponential sums over finite fields. An application of the
bound to the design of large families of eight-phase
sequences having low correlation is also
given.},
Key = {fds235818}
}

@article{fds235819,
Author = {McLaughlin, SW and Calderbank, AR and Laroia, R},
Title = {Modulation codes for multi-amplitude optical recording
channels},
Journal = {National Conference Publication - Institution of Engineers,
Australia},
Volume = {2},
Number = {94 /9},
Pages = {941-945},
Year = {1994},
Abstract = {We consider the problem of coding for a recording channel.
Traditional magnetic or optical channels employ saturation
recording, where the input to the channel is a two-level
waveform. A new optical recording channel has been developed
that supports unsaturated, M-ary (M≥3) signal levels. In
this paper we introduce the new channel and discuss
modulation codes for it. In particular, we consider the
analysis and design of new partial response codes for these
channels. Comparisons are made with M-ary runlength limited
codes. The partial response codes achieve the largest known
storage density with coding gains of 3 - 5.5 dB above M-ary
runlength limited codes.},
Key = {fds235819}
}

@article{fds235820,
Author = {Jr, ARH and Kumar, PV and Calderbank, AR and Sloane, NJA and Sole,
P},
Title = {Z4-linearity of Kerdock, Preparata, Goethals, and
related codes},
Journal = {IEEE Transactions on Information Theory},
Volume = {40},
Number = {2},
Pages = {301-319},
Year = {1994},
url = {http://dx.doi.org/10.1109/18.312154},
Abstract = {Certain notorious nonlinear binary codes contain more
codewords than any known linear code. These include the
codes constructed by Nordstrom-Robinson, Kerdock, Preparata,
Goethals, and Delsarte-Goethals. It is shown here that all
these codes can be very simply constructed as binary images
under the Gray map of linear codes over Z4, the integers mod
4 (although this requires a slight modification of the
Preparata and Goethals codes). The construction implies that
all these binary codes are distance invariant. Duality in
the Z4 domain implies that the binary images have dual
weight distributions. The Kerdock and 'Preparata' codes are
duals over Z4 - and the Nordstrom-Robinson code is self-dual
- which explains why their weight distributions are dual to
each other. The Kerdock and 'Preparata' codes are
Z4-analogues of first-order Reed-Muller and extended Hamming
codes, respectively. All these codes are extended cyclic
codes over Z4, which greatly simplifies encoding and
decoding. An algebraic hard-decision decoding algorithm is
given for the 'Preparata' code and a Hadamard-transform
soft-decision decoding algorithm for the Kerdock code.
Binary first-and second-order Reed-Muller codes are also
linear over Z4, but extended Hamming codes of length n ≥
32 and the Golay code are not. Using Z4-linearity, a new
family of distance regular graphs are constructed on the
cosets of the 'Preparata' code.},
Doi = {10.1109/18.312154},
Key = {fds235820}
}

@article{fds235821,
Author = {Calderbank, AR and Georghiades, CN},
Title = {Synchronizable codes for the optical OPPM
channel},
Journal = {IEEE Transactions on Information Theory},
Volume = {40},
Number = {4},
Pages = {1097-1107},
Year = {1994},
url = {http://dx.doi.org/10.1109/18.335965},
Abstract = {Random overlapping pulse-position modulation (OPPM)
sequences result in an unrecoverable error floor on both the
probability of erroneous synchronization and the probability
of symbol error when only chip synchronization is present.
It is known, however, that for a given sequence length M, a
subset of the set of all possible sequences is
synchronizable in the sense that in the absence of noise,
the receiver can correctly symbol synchronize by observing M
or more symbol intervals. In this paper we design
finite-state machines and codes over a J-ary alphabet, which
produce sequences with the property that every subsequence
of length L is synchronizable. Some of the codes, in
addition to being synchronizable, produce a coding gain. For
an optical Poisson channel we introduce joint
synchronization and detection algorithms that utilize the
memory in the encoded sequences to produce joint estimates
of timing and sequences. Their performance is analyzed
through simulations and analytical results.},
Doi = {10.1109/18.335965},
Key = {fds235821}
}

@article{fds236035,
Author = {Calderbank, AR and Fishburn, PC},
Title = {Maximal three-independent subsets of {0, 1,
2}n},
Journal = {Designs, Codes and Cryptography},
Volume = {4},
Number = {4},
Pages = {203-211},
Year = {1994},
ISSN = {0925-1022},
url = {http://dx.doi.org/10.1007/BF01388452},
Abstract = {We consider a variant of the classical problem of finding
the size of the largest cap in the r-dimensional projective
geometry PG(r, 3) over the field IF3 with 3 elements. We
study the maximum size f(n) of a subset S of IF3n with the
property that the only solution to the equation x1+x2+x3=0
is x1=x2=x3. Let cn=f(n)1/n and c=sup{c1, c2, ...}. We prove
that c&gt;2.21, improving the previous lower bound of 2.1955
Doi = {10.1007/BF01388452},
Key = {fds236035}
}

@article{fds236036,
Author = {Betts, W and Calderbank, AR and Laroia, R},
Title = {Performance of nonuniform constellations on the Gaussian
channel},
Journal = {IEEE Transactions on Information Theory},
Volume = {40},
Number = {5},
Pages = {1633-1638},
Year = {1994},
url = {http://dx.doi.org/10.1109/18.333880},
Abstract = {Testing of high-speed voiceband modems has revealed a
significant increase in distortion for points near the
perimeter of a QAM signal constellation. This distortion
increases with distance from the center of the constellation
and limits performance at data rates above 19.2 kb/s. The
perimeter distortion can be reduced by transforming the
signal constellation so that points near the center are
closer together, and points near the perimeter are further
apart. When the channel SNR is high, such a transformation
reduces immunity to Gaussian noise because points near the
center of the transformed constellation are closer together
than in a uniformly spaced constellation with the same
average power. This paper demonstrates theoretically that
for channel SNR's of practical interest, there is actually a
small gain in immunity to Gaussian noise. In fact, an
appropriate coded modulation scheme can produce gains of
Doi = {10.1109/18.333880},
Key = {fds236036}
}

@article{fds235762,
Author = {Vijay Kumar and P and Helleseth, T and Calderbank, AR and Hammons,
AR},
Title = {Large families of quaternary sequences with low
correlation},
Journal = {IEEE International Symposium on Information Theory -
Proceedings},
Pages = {71-},
Year = {1994},
Month = {December},
ISSN = {2157-8095},
url = {http://dx.doi.org/10.1109/ISIT.1994.394899},
Abstract = {A nested chain of quaternary-sequence families having low
correlation values is presented. The families are suitable
for application in CDMA systems employing QPSK
modulation.},
Doi = {10.1109/ISIT.1994.394899},
Key = {fds235762}
}

@article{fds235763,
Author = {Kumar, PV and Helleseth, T and Calderbank, AR},
Title = {Upper bound for some exponential sums over Galois rings and
applications},
Journal = {IEEE International Symposium on Information Theory -
Proceedings},
Pages = {70-},
Year = {1994},
Month = {December},
ISSN = {2157-8095},
url = {http://dx.doi.org/10.1109/ISIT.1994.394900},
Abstract = {An upper bound for Weil-type exponential sums over Galois
rings is presented together with some examples where the
bound is tight. The bound may be regarded as the Galois-ring
analogue of the well-known Weil-Carlitz-Uchiyama bound for
exponential sums over finite fields. An application of the
bound to the design of large families of eight-phase
sequences having low correlation is also
given.},
Doi = {10.1109/ISIT.1994.394900},
Key = {fds235763}
}

@article{fds236037,
Author = {Gelblum, EA and Calderbank, AR},
Title = {Forbidden rate region for generalized cross
constellations},
Journal = {IEEE International Symposium on Information Theory -
Proceedings},
Pages = {149-},
Year = {1995},
Abstract = {An analysis of the Generalized Cross Constellation (GCC) is
presented and a new perspective on its coding algorithm is
described. We show how the GCC can be used to address
generic sets of symbol points in any multidimensional space
through an example based on the matched spectral null coding
used in magnetic recording devices. We also prove that there
is a forbidden rate region of fractional coding rates that
are practically unrealizable using the GCC construction. We
introduce the idea of a constellation tree and show how its
decomposition can be used to design GCC's matching desired
parameters. Following this analysis, an algorithm to design
the optimal rate GCC from a restriction on the maximum size
of its constellation signal set is given, and a formula for
determining the size of the GCC achieving a desired coding
rate is derived. We finish with an upper bound on the size
of the constellation expansion ratio.},
Key = {fds236037}
}

@article{fds236038,
Author = {Seshadri, N and Calderbank, AR and Pottie, G},
Title = {Channel coding for cochannel interference suppression in
wireless communication systems},
Journal = {IEEE Vehicular Technology Conference},
Volume = {2},
Pages = {629-633},
Year = {1995},
Abstract = {Cochannel interference is a major impairment in cellular
systems. In practice the performance of time and frequency
division multiple access (TDMA and FDMA) systems is limited
by a few dominant cochannel interferers. Conventional
channel coding techniques treat this interference as noise
to mitigate its effect. In this work it is shown that
cochannel interference can be totally suppressed by using a
adaptive non-linear decoder. We illustrate our ideas using
codes in real (complex) field as well as codes in finite
field. The decoding technique can be combined with antenna
diversity to offer increased interference suppression
capability.},
Key = {fds236038}
}

@article{fds236039,
Author = {Seshadri, N and Calderbank, AR and Pottie, GJ},
Title = {Channel coding for co-channel interference suppression in
wireless communications},
Journal = {IEEE International Conference on Communications},
Volume = {2},
Pages = {884-888},
Year = {1995},
Abstract = {Co-channel interference is a major impairment in wireless
systems with channel re-use. In practice the performance of
time division multiple access (TDMA) and frequency division
multiple access (FDMA) systems is limited by a few dominant
co-channel interferers. We present channel codes that are
matched to an adaptive linear receiver, so that the
combination provides interference suppression. It is shown
that a simple one symbol parity check code is capable of
suppressing one interferer, a repetition code of length N is
capable of suppressing N-1 interferers, and a code of K
information symbols and N channel symbols is capable of
suppressing N/K interferers. With simple parity check codes
and repetition codes, the tap setting of an adaptive
combiner can be configured using a 20-40 symbol training
sequence. Simulations for multiple cells reveal significant
capacity improvement is possible.},
Key = {fds236039}
}

@article{fds236040,
Author = {Bonnecaze, A and Sole, P and Calderbank, AR},
Title = {Quaternary quadratic residue codes and unimodular
lattices},
Journal = {IEEE Transactions on Information Theory},
Volume = {41},
Number = {2},
Pages = {366-377},
Year = {1995},
url = {http://dx.doi.org/10.1109/18.370138},
Abstract = {We construct new self-dual and isodual codes over the
integers modulo 4. The binary images of these codes under
the Gray map are nonlinear, but formally self-dual. The
construction involves Hensel lifting of binary cyclic codes.
Quaternary quadratic residue codes are obtained by Hensel
lifting of the classical binary quadratic residue codes.
Repeated Hensel lifting produces a universal code defined
over the 2-adic integers. We investigate the connections
between this universal code and the codes defined over Z4,
the composition of the automorphism group, and the structure
of idempotents over Z4. We also derive a square root bound
on the minimum Lee weight, and explore the connections with
the finite Fourier transform. Certain self-dual codes over
Zd are shown to determine even unimodular lattices,
including the extended quadratic residue code of length q +
1, where q ≡ -1(mod 8) is a prime power. When q = 23, the
quaternary Golay code determines the Leech lattice in this
way. This is perhaps the simplest construction for this
remarkable lattice that is known.},
Doi = {10.1109/18.370138},
Key = {fds236040}
}

@article{fds236041,
Author = {Best, MR and Burnashev, MV and Levy, Y and Rabinovich, A and Fishburn,
PC and Calderbank, AR and Jr, DJC},
Title = {On a technique to calculate the exact performance of a
convolutional code},
Journal = {IEEE Transactions on Information Theory},
Volume = {41},
Number = {2},
Pages = {441-447},
Year = {1995},
url = {http://dx.doi.org/10.1109/18.370145},
Abstract = {A Markovian technique is described to calculate the exact
performance of the Viterbi algorithm used as either a
channel decoder or a source encoder for a convolutional
code. The probability of information bit error and the
expected Hamming distortion are computed for codes of
various rates and constraint lengths. The concept of
tie-breaking rules is introduced and its influence on
decoder performance is examined. Computer simulation is used
to verify the accuracy of the results. Finally, we discuss
the issue of when a coded system outperforms an uncoded
system in light of the new results.},
Doi = {10.1109/18.370145},
Key = {fds236041}
}

@article{fds236042,
Author = {Kumar, PV and Helleseth, T and Calderbank, AR},
Title = {Upper bound for Weil exponential sums over Galois rings and
applications},
Journal = {IEEE Transactions on Information Theory},
Volume = {41},
Number = {2},
Pages = {456-468},
Year = {1995},
url = {http://dx.doi.org/10.1109/18.370147},
Abstract = {We present an analog of the well-known Weil-Carlitz-Uchiyama
upper bound for exponential sums over finite fields for
exponential sums over Galois rings. Some examples are given
where the bound is tight. The bound has immediate
application to the design of large families of
phase-shift-keying sequences having low correlation and an
alphabet of size pe, p prime, e ≥ 2. Some new
constructions of eight-phase sequences are
provided.},
Doi = {10.1109/18.370147},
Key = {fds236042}
}

@article{fds236043,
Author = {Calderbank, AR and Fishburn, PC and Rabinovich,
A},
Title = {Covering properties of convolutional codes and associated
lattices},
Journal = {IEEE Transactions on Information Theory},
Volume = {41},
Number = {3},
Pages = {732-746},
Year = {1995},
url = {http://dx.doi.org/10.1109/18.382019},
Abstract = {This study proposes several Markov methods for the analysis
of the expected and worst case performance of sequence-based
methods of quantization. The quantization algorithm is
assumed as a dynamic programming where the current step is
dependent on metric functions. The main objective is to
obtain a concise representation of these metric functions
including the possible trajectories of the dynamic
programming algorithm. To demonstrate this, the quantization
of equiprobable binary data using a convolutional code is
considered. In addition, these methods are also applicable
to the quantization of arbitrary symmetric probability
distributions using convolutional codes. For certain
convolutional codes a formula that depends only on the
distribution of differences for a single pair of path
metrics is derived for expected use.},
Doi = {10.1109/18.382019},
Key = {fds236043}
}

@article{fds236044,
Author = {Calderbank, AR and McGuire, G},
Title = {Z4-linear codes obtained as projections of
Kerdock and Delsarte-Goethals codes},
Journal = {Linear Algebra and its Applications},
Volume = {226-228},
Number = {C},
Pages = {647-665},
Year = {1995},
ISSN = {0024-3795},
url = {http://dx.doi.org/10.1016/0024-3795(95)00239-N},
Abstract = {The Kerdock and Delsarte-Goethals codes can be very simply
constructed as binary images under a certain natural map,
called the Gray map, of linear codes over Z4, the integers
modulo 4. We consider the Gray images of linear codes over
Z4 obtained from the Kerdock and Delsarte-Goethals codes by
projection on a hyperplane. For m odd, certain Gray images
have the same weight distribution as duals of extended
binary BCH codes of length 2m, but are not equivalent to
these codes. Inequivalence follows from a general theorem
identifying binary linear codes that are not Gray images of
linear codes over Z4. © 1995.},
Doi = {10.1016/0024-3795(95)00239-N},
Key = {fds236044}
}

@article{fds236045,
Author = {Calderbank, AR and Sloane, NJA},
Title = {Modular and p-adic cyclic codes},
Journal = {Designs, Codes and Cryptography},
Volume = {6},
Number = {1},
Pages = {21-35},
Year = {1995},
ISSN = {0925-1022},
url = {http://dx.doi.org/10.1007/BF01390768},
Abstract = {This paper presents some basic theorems giving the structure
of cyclic codes of length n over the ring of integers modulo
pa and over the p-adic numbers, where p is a prime not
dividing n. An especially interesting example is the 2-adic
cyclic code of length 7 with generator polynomial
X3+λX2+(λ-1)X-1, where λ satisfies λ2 - λ + 2 = 0. This
is the 2-adic generalization of both the binary Hamming code
and the quaternary octacode (the latter being equivalent to
the Nordstrom-Robinson code). Other examples include the
2-adic Golay code of length 24 and the 3-adic Golay code of
length 12. © 1995 Kluwer Academic Publishers.},
Doi = {10.1007/BF01390768},
Key = {fds236045}
}

@article{fds236046,
Author = {McGuire, G and Calderbank, AR},
Title = {Proof of a conjecture of sarwate and pursley regarding pairs
of binary m-sequences},
Journal = {IEEE Transactions on Information Theory},
Volume = {41},
Number = {4},
Pages = {1153-1155},
Year = {1995},
url = {http://dx.doi.org/10.1109/18.391260},
Abstract = {Binary m-sequences are maximal length sequences generated by
shift registers of length m, that are employed in
systems, because of their crosscorrelation properties. It is
well known that given a pair of distinct m-sequences, the
crosscorrelation function must take on at least three
values. This correspondence considers crosscorrelation
functions that take on exactly three values, and where these
values are preferred in that they are small. The main result
is a proof of a conjecture made by Sarwate and Pursley in
1980, that if m ≡ 0 (mod 4) then there are no preferred
pairs of binary m-sequences. The proof makes essential use
of a deep theorem of McEliece that restricts the possible
weights that can occur in a binary cyclic
code.},
Doi = {10.1109/18.391260},
Key = {fds236046}
}

@article{fds236047,
Author = {Pottie, GJ and Calderbank, AR},
Title = {Channel coding strategies for cellular radio},
Journal = {IEEE Transactions on Vehicular Technology},
Volume = {44},
Number = {4},
Pages = {763-770},
Year = {1995},
url = {http://dx.doi.org/10.1109/25.467960},
Abstract = {To improve re-use of time/frequency slots in a cellular
radio system, it is desirable for the average interference
levels seen by all users to be made approximately equal. We
provide constructions based on orthogonal latin squares that
guarantee different sets of users will interfere in
successive slots. When signal to interference ratios are
independent from successive symbols, channel codes can
provide a large diversity gain which is far in excess of the
gain against additive noise. Consequently, coding with
interleaving fits together very naturally with this
construction. We illustrate how to achieve large performance
improvement using convolutional codes with low decoding
delay in a slow hopped system.},
Doi = {10.1109/25.467960},
Key = {fds236047}
}

@article{fds236048,
Author = {Calderbank, AR and Shor, PW},
Title = {Good quantum error-correcting codes exist},
Journal = {Physical Review A - Atomic, Molecular, and Optical
Physics},
Volume = {54},
Number = {2},
Pages = {1098-1105},
Year = {1996},
Abstract = {A quantum error-correcting code is defined to be a unitary
mapping (encoding) of k qubits (two-state quantum systems)
into a subspace of the quantum state space of n qubits such
that if any t of the qubits undergo arbitrary decoherence,
not necessarily independently, the resulting n qubits can be
used to faithfully reconstruct the original quantum state of
the k encoded qubits. Quantum error-correcting codes are
shown to exist with asymptotic rate k/n = 1-2H2(2t/n) where
H2(P) is the binary entropy function -plog2p-(1 -p)log2(l -
p). Upper bounds on this asymptotic rate are
given.},
Key = {fds236048}
}

@article{fds236049,
Author = {Calderbank, AR and McGuire, G and Kumar, PV and Helleseth,
T},
Title = {Cyclic codes over ℤ4 locator polynomials, and
newton's identities},
Journal = {IEEE Transactions on Information Theory},
Volume = {42},
Number = {1},
Pages = {217-226},
Year = {1996},
ISSN = {0018-9448},
url = {http://dx.doi.org/10.1109/18.481791},
Abstract = {Certain nonlinear binary codes contain more code-words than
any comparable linear code presently known. These include
the Kerdock and Preparata codes that can be very simply
constructed as binary images, under the Gray map, of linear
codes over ℤ4 that are defined by means of parity checks
involving Galois rings. This paper describes how Fourier
transforms on Galois rings and elementary symmetric
functions can be used to derive lower bounds on the minimum
distance of such codes. These methods and techniques from
algebraic geometry are applied to find the exact minimum
distance of a family of ℤ4-linear codes with length 2m (m,
odd) and size 22m+1-5m-2. The Gray image of the code of
length 32 is the best (64, 237) code that is presently
known. This paper also determines the exact minimum Lee
distance of the linear codes over ℤ4 that are obtained
from the extended binary two- and three-error-correcting BCH
codes by Hensel lifting. The Gray image of the Hensel lift
of the three-error-correcting BCH code of length 32 is the
best (64, 232) code that is presently known. This code also
determines an extremal 32-dimensional even unimodular
lattice. © 1996 IEEE.},
Doi = {10.1109/18.481791},
Key = {fds236049}
}

@article{fds236050,
Author = {Calderbank, AR},
Title = {Signal design for co-channel interference suppression with
applications to wireless communications},
Journal = {Electro International, Conference Proceedings},
Pages = {47-},
Year = {1996},
Abstract = {Co-channel interference is a major impairment in wireless
systems with channel (frequency and/or time) re-use. In
practice the performance of Time Division Multiple Access
(TDMA) and Frequency Division Multiple Access (FDMA) systems
is limited by a few dominant co-channel interferers. These
can be removed by means of multiple antennas but it is
difficult to demand this at the mobile because of technology
limitations. The standard solution is to treat co-channel
interference as Gaussian noise and to employ powerful
channel codes. However, this solution is far from optimal
since the decoder is using an inappropriate metric for
decoding. In this paper it is shown that a more effective
use of system redundancy is to design channel codes that are
matched to an adaptive linear receiver, so that the
combination provides interference suppression. It is shown
that a simple one symbol parity check code is capable of
suppressing one interferer, a repetition code of length N is
capable of suppressing N - 1 interferers, and a code of K
information symbols and N channel symbols is capable of
suppressing N/K interferers.},
Key = {fds236050}
}

@article{fds236051,
Author = {Kumar, PV and Helleseth, T and Calderbank, AR and Jr,
ARH},
Title = {Large families of quaternary sequences with low
correlation},
Journal = {IEEE Transactions on Information Theory},
Volume = {42},
Number = {2},
Pages = {579-592},
Year = {1996},
ISSN = {0018-9448},
url = {http://dx.doi.org/10.1109/18.485726},
Abstract = {A family of quaternary (Z4-alphabet) sequences of length L =
T -1, size M &gt; L2 +3X+2, and maximum nontrivial
correlation parameter Cmax &lt; 2√L + 1 + 1 is presented.
The sequence family always contains the four-phase family A.
When r is odd, it includes the family of binary Gold
sequences. The sequence family is easily generated using two
shift registers, one binary, the other quaternary. The
distribution of correlation values is provided. The
construction can be extended to produce a chain of sequence
families, with each family in the chain containing the
preceding family. This gives the design flexibility with
respect to the number of intermittent users that can be
supported, in a code-division multiple-access cellular radio
system. When r is odd, the sequence families in the chain
correspond to shortened Z4 -linear versions of the
Delsarte-Goethals codes. Index Terms-. © 1996
IEEE.},
Doi = {10.1109/18.485726},
Key = {fds236051}
}

@article{fds236052,
Author = {Calderbank, AR and Sloane, NJA},
Title = {The ternary golay code, the integers mod 9, and the
coxeter-todd lattice},
Journal = {IEEE Transactions on Information Theory},
Volume = {42},
Number = {2},
Pages = {636-637},
Year = {1996},
ISSN = {0018-9448},
url = {http://dx.doi.org/10.1109/18.485733},
Abstract = {The 12-dimensinnal Coxeter-Todd lattice can be obtained by
lifting the ternary Golay code to a code over the integers
mod 9 and applying Construction A. © 1996
IEEE.},
Doi = {10.1109/18.485733},
Key = {fds236052}
}

@article{fds236053,
Author = {Calderbank, AR and McGuire, G and Poonen, B and Rubinstein,
M},
Title = {On a conjecture of Helleseth regarding pairs of binary
m-sequences},
Journal = {IEEE Transactions on Information Theory},
Volume = {42},
Number = {3},
Pages = {988-990},
Year = {1996},
ISSN = {0018-9448},
url = {http://dx.doi.org/10.1109/18.490561},
Abstract = {Binary m-sequences are maximal-length sequences generated by
shift registers of length m, that are employed in
well known that given a pair of distinct /«-sequences, the
crosscorrelation function must take on at least three
values. This correspondence addresses a conjecture made by
Helleseth in 1976, that if rn is a power of 2, then there
are no pairs of binary m-sequences with a 3-valued
crosscorrelation function. This conjecture is proved under
the assumption that the three correlation values are
Doi = {10.1109/18.490561},
Key = {fds236053}
}

@article{fds235822,
Author = {Calderbank, AR and Mcguire, G},
Title = {Construction of a (64,237,12) Code via Galois
Rings},
Journal = {Designs, Codes, and Cryptography},
Volume = {10},
Number = {2},
Pages = {157-165},
Year = {1997},
Abstract = {Certain nonlinear binary codes contain more codewords than
any comparable linear code presently known. These include
the Kerdock and Preparata codes, which exist for all lengths
4m ≥ 16. At length 16 they coincide to give the
Nordstrom-Robinson code. This paper constructs a nonlinear
(64, 237, 12) code as the binary image, under the Gray map,
of an extended cyclic code defined over the integers modulo
4 using Galois rings. The Nordstrom-Robinson code is defined
in this same way, and like the Nordstrom-Robinson code, the
new code is better than any linear code that is presently
known.},
Key = {fds235822}
}

@article{fds235823,
Author = {Calderbank, AR and Rains, EM and Shor, PW and Sloane,
NJA},
Title = {Quantum error correction and orthogonal geometry},
Journal = {Physical Review Letters},
Volume = {78},
Number = {3},
Pages = {405-408},
Year = {1997},
Abstract = {A group theoretic framework is introduced that simplifies
the description of known quantum error-correcting codes and
greatly facilitates the construction of new examples. Codes
are given which map 3 qubits to 8 qubits correcting 1 error,
4 to 10 qubits correcting 1 error, 1 to 13 qubits correcting
2 errors, and 1 to 29 qubits correcting 5
errors.},
Key = {fds235823}
}

@article{fds235824,
Author = {Seshadri, N and Tarokh, V and Calderbank, AR},
Title = {Space-time codes for wireless communication: Code
construction},
Journal = {IEEE Vehicular Technology Conference},
Volume = {2},
Pages = {637-641},
Year = {1997},
Abstract = {We consider the design of channel codes for improving the
data rate and/or the reliability of communications over
fading channels using multiple transmit antennas. Here, data
is encoded by a channel code and the encoded data is split
into n streams that are simultaneously transmitted using n
transmit antennas. The received signal at each receive
antenna is a linear superposition of the n transmitted
signals. We review the performance criteria for designing
such codes under the assumption that the fading is slow and
frequency non-selective established in [3]. Performance is
determined by diversity gain quantified by ranks and coding
gain quantified by determinants of certain matrices that are
constructed from the code sequences. The performance
criterion is then used to design trellis codes for high data
rate wireless communication. These codes are easy to encode
and decode. They provide the best trade-off between data
rate, diversity gain, constellation size and trellis
complexity. Simulation results are provided for 4 and 8 PSK
signal sets with data rates of 2 and 3 bits/symbol,
demonstrating excellent performance that is within 2-3 dB of
the outage capacity for these channels.},
Key = {fds235824}
}

@article{fds235825,
Author = {Tarokh, V and Naguib, AF and Seshadri, N and Calderbank,
AR},
Title = {Space-time codes for high data rate wireless communication:
Mismatch analysis},
Journal = {IEEE International Conference on Communications},
Volume = {1},
Pages = {309-313},
Year = {1997},
Abstract = {We revisit Space-Time Codes for a mobile communication
system that employs multiple antennas at the base and
optional antenna diversity at the mobile station. The
realistic case when the channel state is not completely
known is considered. It is assumed that the channel
estimator extracts the fade coefficients using orthogonal
pilot tones. Mismatch analysis is then carried out. It is
proved that in the absence of ideal channel state
information the design criteria for space-time codes
developed in [11] is still valid for equal energy
constellation case. Using our derivation, it is observed
that channel estimation techniques commonly used over
rapidly fading channels can be used in conjunction with
space-time codes provided that the number of transmit
antennas is small.},
Key = {fds235825}
}

@article{fds235826,
Author = {Calderbank, AR and Seshadri, N and Tarokh, V},
Title = {Space-time codes for wireless communication},
Journal = {IEEE International Symposium on Information Theory -
Proceedings},
Pages = {146-},
Year = {1997},
Abstract = {The design of channel codes for improvement the data rate
and/or the reliability of communications over fading
channels using multiple transmit antennas is considered. A
design criterion is provided and is then used to design
space-time codes for high data rate wireless communication.
These codes are trellis codes that are easy to encode and
decode and have remarkable performance.},
Key = {fds235826}
}

@article{fds235827,
Author = {Tarokh, V and Seshadri, N and Calderbank, AR},
Title = {Space-time codes for high data rate wireless communication:
Performance criteria},
Journal = {IEEE International Conference on Communications},
Volume = {1},
Pages = {299-303},
Year = {1997},
Abstract = {We consider the design of channel codes for improving the
data rate and/or the reliability of communications over
fading channels using multiple transmit antennas. Here, data
is encoded by a channel code and the encoded data is split
into n streams that are simultaneously transmitted using n
transmit antennas. The received signal at each receive
antenna is a linear superposition of the n transmitted
signals. We derive performance criteria for designing
channel codes under the assumption that the fading is slow
and frequency non-selective. Performance is shown to be
determined by diversity gain quantified by ranks and coding
gain quantified by determinants of certain matrices that are
constructed from the code sequences.},
Key = {fds235827}
}

@article{fds235828,
Author = {Calderbank, AR and Daubechies, I and Sweldens, W and Yeo,
B-L},
Title = {Lossless image compression using integer to integer wavelet
transforms},
Journal = {IEEE International Conference on Image Processing},
Volume = {1},
Pages = {596-599},
Year = {1997},
Abstract = {Invertible wavelet transforms that map integers to integers
are important for lossless representations. In this paper,
we present an approach to build integer to integer wavelet
transforms based upon the idea of factoring wavelet
transforms into lifting steps. This allows the construction
of an integer version of every wavelet transform. We
demonstrate the use of these transforms in lossless image
compression.},
Key = {fds235828}
}

@article{fds236054,
Author = {Calderbank, AR and Rains, EM and Shor, PW and Sloane,
NJA},
Title = {Quantum error correction via codes over GF(4)},
Journal = {IEEE International Symposium on Information Theory -
Proceedings},
Pages = {292-},
Year = {1997},
Abstract = {The unreasonable effectiveness of quantum computing is
founded on coherent quantum superposition or entanglement
which allows a large number of calculations to be performed
simultaneously. This coherence is lost as a quantum system
interacts with its environment. In the present paper the
problem of finding quantum-error-correcting codes is
transformed into one of finding additive codes over the
field GF(4) which are self-orthogonal with respect to a
certain trace inner product. Many new codes and new bounds
are presented, as well as a table of upper and lower bounds
on such codes of length up to 30 qubits.},
Key = {fds236054}
}

@article{fds236055,
Author = {Gelblum, EA and Calderbank, AR},
Title = {A forbidden rate region for generalized cross
constellations},
Journal = {IEEE Transactions on Information Theory},
Volume = {43},
Number = {1},
Pages = {335-341},
Year = {1997},
ISSN = {0018-9448},
url = {http://dx.doi.org/10.1109/18.567754},
Abstract = {An analysis of the Generalized Cross Constellation (GCC) is
presented and a new perspective on its coding algorithm is
described. We show how the GCC can be used to address
generic sets of symbol points in any multidimensional space
through an example based on the matched spectral null coding
used in magnetic recording devices. We also prove that there
is a forbidden rate region of fractional coding rates that
are practically unrealizable using the GCC construction. We
introduce the idea of a constellation tree and show how its
decomposition can be used to design GCC's matching desired
parameters. Following this analysis, an algorithm to design
the optimal rate GCC from a restriction on the maximum size
of its constellation signal set is given, and a formula for
determining the size of the GCC achieving a desired coding
rate is derived. We finish with an upper bound on the size
of the constellation expansion ratio. © 1997
IEEE.},
Doi = {10.1109/18.567754},
Key = {fds236055}
}

@article{fds236056,
Author = {Calderbank, AR and Li, W-CW and Poonen, B},
Title = {A 2-adic approach to the analysis of cyclic
codes},
Journal = {IEEE Transactions on Information Theory},
Volume = {43},
Number = {3},
Pages = {977-986},
Year = {1997},
ISSN = {0018-9448},
url = {http://dx.doi.org/10.1109/18.568706},
Abstract = {This paper describes how 2-adic numbers can be used to
analyze the structure of binary cyclic codes and of cyclic
codes defined over ℤ 2a, a ≥ 2, the ring of integers
modulo 2 a. It provides a 2-adic proof of a theorem of
McEliece that characterizes the possible Hamming weights
that can appear in a binary cyclic code. A generalization of
this theorem is derived that applies to cyclic codes over
ℤ 2a that are obtained from binary cyclic codes by a
sequence of Hensel lifts. This generalization characterizes
the number of times a residue modulo 2 a appears as a
component of an arbitrary codeword in the cyclic code. The
limit of the sequence of Hensel lifts is a universal code
defined over the 2-adic integers. This code was first
introduced by Calderbank and Sloane (1995), and is the main
subject of this paper. Binary cyclic codes and cyclic codes
over ℤ 2aare obtained from these universal codes by
reduction modulo some power of 2. A special case of
particular interest is cyclic codes over ℤ 4 that are
obtained from binary cyclic codes by means of a single
Hensel lift. The binary images of such codes under the Gray
isometry include the Kerdock, Preparata, and
Delsarte-Goethals codes. These are nonlinear binary codes
that contain more codewords than any linear code presently
known. Fundamental understanding of the composition of
codewords in cyclic codes over ℤ 4 is central to the
search for more families of optimal codes. This paper also
constructs even unimodular lattices from the Hensel lift of
extended binary cyclic codes that are self-dual with all
Hamming weights divisible by 4. The Leech lattice arises in
this way as do extremal lattices in dimensions 32 through
48. © 1997 IEEE.},
Doi = {10.1109/18.568706},
Key = {fds236056}
}

@article{fds236057,
Author = {Tarokh, V and Naguib, A and Seshadri, N and Calderbank,
AR},
Title = {Low-rate multi-dimensional space-time codes for both slow
and rapid fading channels},
Journal = {IEEE International Symposium on Personal, Indoor and Mobile
Volume = {3},
Pages = {1206-1210},
Year = {1997},
Abstract = {We consider the design of channel codes for improving the
data rate and/or the reliability of communications using
multiple transmit antennas over a fading channel. It is
assumed that the transmitter does not know the channel but
seeks to choose a codebook that guarantees a diversity gain
of r1 when there is no mobility and a diversity gain of
r2≥r1 when the channel is fast fading. A solution to this
problem is unveiled in this paper. Here, the encoded data is
split into n streams that are simultaneously transmitted
using n transmit antennas. The signal received at each
receive antenna is a superposition of the faded versions of
the n transmitted signals. We derive performance criteria
for designing codes having the aforementioned properties.
Performance is shown to be determined by diversity advantage
quantified by a rank/distance and coding advantage
quantified by a determinant/product criterion. The criteria
is used to design codes for both slow and rapid fading
channels. The constructed codes have remarkable performance
in low signal to noise ratios and are suitable for improving
the frequency reuse factor under a variety of mobility
conditions.},
Key = {fds236057}
}

@article{fds236058,
Author = {Calderbank, AR and Cameron, PJ and Kantor, WM and Seidel,
JJ},
Title = {ℤ4-kerdock codes, orthogonal spreads, and
extremal euclidean line-sets},
Journal = {Proceedings of the London Mathematical Society},
Volume = {75},
Number = {2},
Pages = {436-480},
Year = {1997},
ISSN = {0024-6115},
Key = {fds236058}
}

@article{fds236059,
Author = {Calderbank, AR and Sloane, NJA},
Title = {Double Circulant Codes over ℤ4 and even
Unimodular Lattices},
Journal = {Journal of Algebraic Combinatorics},
Volume = {6},
Number = {2},
Pages = {119-131},
Year = {1997},
Abstract = {With the help of some new results about weight enumerators
of self-dual codes over ℤ4 we investigate a class of
double circulant codes over ℤ4, one of which leads to an
extremal even unimodular 40-dimensional lattice. It is
conjectured that there should be "Nine more constructions of
the Leech lattice".},
Key = {fds236059}
}

@article{fds235829,
Author = {Calderbank, AR and Daubechies, I and Sweldens, W and Yeo,
B-L},
Title = {Wavelet Transforms That Map Integers to Integers},
Journal = {Applied and Computational Harmonic Analysis},
Volume = {5},
Number = {3},
Pages = {332-369},
Year = {1998},
Abstract = {Invertible wavelet transforms that map integers to integers
have important applications in lossless coding. In this
paper we present two approaches to build integer to integer
wavelet transforms. The first approach is to adapt the
precoder of Laroia et al., which is used in information
transmission; we combine it with expansion factors for the
high and low pass band in subband filtering. The second
approach builds upon the idea of factoring wavelet
transforms into socalled lifting steps. This allows the
construction of an integer version of every wavelet
transform. Finally, we use these approaches in a lossless
image coder and compare the results to those given in the
Key = {fds235829}
}

@article{fds236060,
Author = {Fan, JL and Calderbank, AR},
Title = {A modified concatenated coding scheme, with applications to
magnetic data storage},
Journal = {IEEE Transactions on Information Theory},
Volume = {44},
Number = {4},
Pages = {1565-1574},
Year = {1998},
ISSN = {0018-9448},
url = {http://dx.doi.org/10.1109/18.681333},
Abstract = {When a block modulation code is concatenated with an
errorcorrection code (ECC) in the standard way, the use of a
modulation code with long blocklengths results in error
propagation. This correspondence analyzes the performance of
modified concatenation, which involves reversing the order
of modulation and ECC. This modified scheme reduces error
propagation, provides greater flexibility in the choice of
parameters, and facilitates soft-decision decoding, with
little or no loss in transmission rate. In particular,
examples are presented which show how this technique can
allow fewer interleaves per sector in hard disk drives, and
permit the use of more sophisticated block modulation codes
which are better suited to the channel. © 1998
IEEE.},
Doi = {10.1109/18.681333},
Key = {fds236060}
}

@article{fds236061,
Author = {Tarokh, V and Seshadri, N and Calderbank, AR},
Title = {Space-time codes for high data rate wireless communication:
Performance criterion and code construction},
Journal = {IEEE Transactions on Information Theory},
Volume = {44},
Number = {2},
Pages = {744-765},
Year = {1998},
ISSN = {0018-9448},
url = {http://dx.doi.org/10.1109/18.661517},
Abstract = {We consider the design of channel codes for improving the
data rate and/or the reliability of communications over
fading channels using multiple transmit antennas. Data is
encoded by a channel code and the encoded data is split into
n streams that are simultaneously transmitted using n
transmit antennas. The received signal at each receive
antenna is a linear superposition of the n transmitted
signals perturbed by noise. We derive performance criteria
for designing such codes under the assumption that the
fading is slow and frequency nonselective. Performance is
shown to be determined by matrices constructed from pairs of
distinct code sequences. The minimum rank among these
matrices quantifies the diversity gain, while the minimum
determinant of these matrices quantifies the coding gain.
The results are then extended to fast fading channels. The
design criteria are used to design trellis codes for high
data rate wireless communication. The encoding/decoding
complexity of these codes is comparable to trellis codes
employed in practice over Gaussian channels. The codes
constructed here provide the best tradeoff between data
rate, diversity advantage, and trellis complexity.
Simulation results are provided for 4 and 8 PSK signal sets
with data rates of 2 and 3 bits/symbol, demonstrating
excellent performance that is within 2-3 dB of the outage
capacity for these channels using only 64 state encoders. ©
1998 IEEE.},
Doi = {10.1109/18.661517},
Key = {fds236061}
}

@article{fds236062,
Author = {Calderbank, AR},
Title = {The art of signaling: fifty years of coding
theory},
Journal = {IEEE Transactions on Information Theory},
Volume = {44},
Number = {6},
Pages = {2561-2595},
Year = {1998},
ISSN = {0018-9448},
url = {http://dx.doi.org/10.1109/18.720549},
Abstract = {In 1948 Shannon developed fundamental limits on the
efficiency of communication over noisy channels. The coding
theorem asserts that there are block codes with code rates
arbitrarily close to channel capacity and probabilities of
error arbitrarily close to zero. Fifty years later, codes
for the Gaussian channel have been discovered that come
close to these fundamental limits. There is now a
substantial algebraic theory of error-correcting codes with
as many connections to mathematics as to engineering
practice, and the last 20 years have seen the construction
of algebraic-geometry codes that can be encoded and decoded
in polynomial time, and that beat the Gilbert-Varshamov
bound. Given the size of coding theory as a subject, this
review is of necessity a personal perspective, and the focus
is reliable communication, and not source coding or
cryptography. The emphasis is on connecting coding theories
for Hamming and Euclidean space and on future challenges,
specifically in data networking, wireless communication, and
quantum information theory. © 1998 IEEE.},
Doi = {10.1109/18.720549},
Key = {fds236062}
}

@article{fds236063,
Author = {Naguib, AF and Seshadri, N and Calderbank, AR},
Title = {Applications of space-time block codes and interference
suppression for high capacity and high data rate wireless
systems},
Journal = {Conference Record of the Asilomar Conference on Signals,
Systems and Computers},
Volume = {2},
Pages = {1803-1810},
Year = {1998},
Abstract = {This paper presents a combined interference suppression and
ML decoding scheme for space-time block codes that can
effectively suppress interference from other co-channel
users while providing each user with a diversity benefit. We
consider a multiuser environment with K synchronous
co-channel users, each is equipped with N transmit antennas
and uses the space-time block coding. By exploiting the
temporal and spatial structure of these codes, we develop a
minimum mean-squared error (MMSE) interference suppression
technique. Assuming that the receiver uses M≥K receive
antennas, these technique will perfectly suppress the
interference from the K-1 co-channel space-time users and
provide a diversity order of N×(M-K+1) to each of the K
users. Moreover, this MMSE solution tends itself to an
adaptive implementation and does not require any explicit
knowledge about the interference. In conjunction with this
interference suppression technique, we show how space-time
block codes can be used to increasing the capacity and/or
data rate of wireless communication systems.},
Key = {fds236063}
}

@article{fds236064,
Author = {Naguib, AF and Tarokh, V and Seshadri, N and Calderbank,
AR},
Title = {A space-time coding modem for high-data-rate wireless
communications},
Journal = {IEEE Journal on Selected Areas in Communications},
Volume = {16},
Number = {8},
Pages = {1459-1477},
Year = {1998},
ISSN = {0733-8716},
url = {http://dx.doi.org/10.1109/49.730454},
Abstract = {This paper presents the theory and practice of a new
advanced modem technology suitable for high-data-rate
wireless communications and presents its performance over a
frequency-flat Rayleigh fading channel. The new technology
is based on space-time coded modulation (STCM) [1]-[5] with
multiple transmit and/or multiple receive antennas and
orthogonal pilot sequence insertion (O-PSI). In this
approach, data is encoded by a space-time (ST) channel
encoder and the output of the encoder is split into N
streams to be simultaneously transmitted using N transmit
antennas. The transmitter inserts periodic orthogonal pilot
sequences in each of the simultaneously transmitted bursts.
The receiver uses those pilot sequences to estimate the
fading channel. When combined with an appropriately designed
interpolation filter, accurate channel state information
(CSI) can be estimated for the decoding process. Simulation
results of the proposed modem, as applied to the IS-136
cellular standard, are presented. We present the frame error
rate (FER) performance results as a function of the
signal-to-noise ratio (SNR) and the maximum Doppler
frequency, in the presence of timing and frequency offset
errors. Simulation results show that for 10% FER, a 32-state
eight-phase-shift keyed (8-PSK) ST code with two transmit
and two receive antennas can support data rates up to 55.8
kb/s on a 30-kHz channel, at an SNR of 11.7 dB and a maximum
Doppler frequency of 180 Hz. Simulation results for other
codes and other channel conditions are also provided. We
also compare the performance of the proposed STCM scheme
with delay-diversity schemes and conclude that STCM can
provide significant SNR improvement over simple delay
diversity.},
Doi = {10.1109/49.730454},
Key = {fds236064}
}

@article{fds235757,
Author = {Vaishampayan, VA and Calderbank, AR and Batllo,
JC},
Title = {On reducing granular distortion in multiple description
quantization},
Journal = {IEEE International Symposium on Information Theory -
Proceedings},
Pages = {98},
Year = {1998},
Month = {December},
ISSN = {2157-8095},
url = {http://dx.doi.org/10.1109/ISIT.1998.708685},
Abstract = {There is a gap of 3.07 dB between the distortion product of
a multiple description quantizer and the multiple
description rate distortion bound. In this paper we seek to
close this gap through the design of a quantizer with
smaller granular distortion. © 1998 IEEE.},
Doi = {10.1109/ISIT.1998.708685},
Key = {fds235757}
}

@article{fds235758,
Author = {Calderbank, AB and Forney, GD and Vardy, A},
Title = {Minimal tail-biting trellises: The Golay code and
more},
Journal = {IEEE International Symposium on Information Theory -
Proceedings},
Pages = {255},
Year = {1998},
Month = {December},
ISSN = {2157-8095},
url = {http://dx.doi.org/10.1109/ISIT.1998.708860},
Abstract = {A 16-state tail-biting trellis for the binary (24,12,8)
Golay code C 24 is exhibited. This tail-biting trellis is
minimal. It has many other nice properties, and may be
simpler to decode than the minimal conventional trellis for
C 24 . Unwrapping this tail-biting trellis produces a
periodically-time-varying 16-state rate-1/2 convolutional
code. This «Golay convolutional code» is the first known
example of a self-dual doubly-even binary linear
convolutional code. It has greater minimum distance than any
16-state time-invariant convolutional code of rate 1/2.
Demonstrably minimal tail-biting trellises are given for
several other binary and nonbinary self-dual codes. For some
nonbinary codes, tail-biting trellises based on code
generators over a group are simpler than any tail-biting
trellis based on linear generators over a field. © 1998
IEEE.},
Doi = {10.1109/ISIT.1998.708860},
Key = {fds235758}
}

@article{fds235771,
Author = {Tarokh, V and Naguib, A and Seshadri, N and Calderbank,
AR},
Title = {Recent progress in space-time block and trellis
coding},
Journal = {IEEE International Symposium on Information Theory -
Proceedings},
Pages = {314},
Year = {1998},
Month = {December},
ISSN = {2157-8095},
url = {http://dx.doi.org/10.1109/ISIT.1998.708919},
Abstract = {Techniques for transmission and reception over wireless
channels using multiple transmit antennas are presented. ©
1998 IEEE.},
Doi = {10.1109/ISIT.1998.708919},
Key = {fds235771}
}

@article{fds236065,
Author = {Tarokh, V and Jafarkhani, H and Calderbank, AR},
Title = {Space-time block codes from orthogonal designs},
Journal = {IEEE Transactions on Information Theory},
Volume = {45},
Number = {5},
Pages = {1456-1467},
Year = {1999},
ISSN = {0018-9448},
url = {http://dx.doi.org/10.1109/18.771146},
Abstract = {The theory of space-time block coding is presented as a
simple and elegant method for transmission using multiple
transmit antennas in a wireless Rayleigh/Rician environment.
These codes have a very simple maximum-likelihood decoding
algorithm which is only based on linear processing. Designs
that correspond to combined coding and linear processing at
the transmitter are also considered.},
Doi = {10.1109/18.771146},
Key = {fds236065}
}

@article{fds236066,
Author = {Calderbank, AR and Harbin, RH and Rains, EM and Shor, PW and Sloane,
NJA},
Title = {A Group-Theoretic Framework for the Construction of Packings
in Grassmannian Spaces},
Journal = {Journal of Algebraic Combinatorics},
Volume = {9},
Number = {2},
Pages = {129-140},
Year = {1999},
Abstract = {By using totally isotropic subspaces in an orthogonal space
Ω+(2i, 2), several infinite families of packings of
2k-dimensional subspaces of real 2i -dimensional space are
constructed, some of which are shown to be optimal packings.
A certain Clifford group underlies the construction and
links this problem with Barnes-Wall lattices, Kerdock sets
and quantum-error-correcting codes.},
Key = {fds236066}
}

@article{fds236067,
Author = {Calderbank, AR and Jr, GDF and Vardy, A},
Title = {Minimal tail-biting trellises: the Golay code and
more},
Journal = {IEEE Transactions on Information Theory},
Volume = {45},
Number = {5},
Pages = {1435-1455},
Year = {1999},
ISSN = {0018-9448},
url = {http://dx.doi.org/10.1109/18.771145},
Abstract = {Tail-biting trellis representations of block codes are
investigated. We develop some elementary theory, and present
several intriguing examples, which we hope will stimulate
further developments in this field. In particular, we
construct a 16-state 12-section structurally invariant
tail-biting trellis for the (24, 12, 8) binary Golay code.
This tail-biting trellis representation is minimal: it
simultaneously minimizes all conceivable measures of state
complexity. Moreover, it compares favorably with the minimal
conventional 12-section trellis for the Golay code, which
has 256 states at its midpoint, or with the best
quasi-cyclic representation of this code, which leads to a
64-state tail-biting trellis. Unwrapping this tail-biting
trellis produces a periodically time-varying 16-state rate-
1/2 'convolutional Golay code' with d = 8, which has
attractive performance/complexity properties. We furthermore
show that the (6, 3, 4) quarternary hexacode has a minimal
8-state group tail-biting trellis, even though it has no
such linear trellis over F 4. Minimal tail-biting trellises
are also constructed for the (8, 4, 4) binary Hamming code,
the (4, 2, 3) ternary tetracode, the (4, 2, 3) code over F
4, and the Z 4-linear (8, 4, 4) octacode.},
Doi = {10.1109/18.771145},
Key = {fds236067}
}

@article{fds236068,
Author = {Calderbank, AR and Duel-Hallen, A and Fishburn, PC and Rabinovich,
A},
Title = {Interpolation by convolutional codes, overload distortion,
and the erasure channel},
Journal = {IEEE Transactions on Information Theory},
Volume = {45},
Number = {1},
Pages = {94-105},
Year = {1999},
ISSN = {0018-9448},
url = {http://dx.doi.org/10.1109/18.746774},
Abstract = {This paper investigates how closely randomly generated
binary source sequences can be matched by convolutional code
codewords. What distinguishes it from prior work is that a
randomly chosen subsequence with density A is to be matched
as closely as possible. The so-called marked bits of the
subsequence could indicate overload quantization points for
a source sample generated from the tails of a probability
distribution. They might also indicate bits where the
initial estimate is considered reliable, as might happen in
iterated decoding. The capacity of a convolutional code to
interpolate the marked subsequence might be viewed as a
measure of its ability to handle overload distortion. We
analyze this capacity using a Markov chain whose states are
sets of subsets of trellis vertices of the convolutional
code. We investigate the effect of memory on the probability
of perfect interpolation and calculate the residual rate on
the unmarked bits of the binary source sequence. We relate
our interpolation methodology to sequence-based methods of
quantization and use it to analyze the performance of
convolutional codes on the pure erasure channel. © 1999
IEEE.},
Doi = {10.1109/18.746774},
Key = {fds236068}
}

@article{fds236069,
Author = {Tarokh, V and Jafarkhani, H and Calderbank, AR},
Title = {Space-time block coding for wireless communications:
Performance results},
Journal = {IEEE Journal on Selected Areas in Communications},
Volume = {17},
Number = {3},
Pages = {451-460},
Year = {1999},
url = {http://dx.doi.org/10.1109/49.753730},
Abstract = {We document the performance of space-time block codes [13],
[14], which provide a new paradigm for transmission over
Rayleigh fading channels using multiple transmit antennas.
Data is encoded using a space-time block code, and the
encoded data is split into n streams which are
simultaneously transmitted using n transmit antennas. The
received signal at each receive antenna is a linear
superposition of the n transmitted signals perturbed by
noise. Maximum likelihood decoding is achieved in a simple
way through decoupling of the signals transmitted from
different antennas rather than joint detection. This uses
the orthogonal structure of the space-time block code and
gives a maximum likelihood decoding algorithm which is based
only on linear processing at the receiver. We review the
encoding and decoding algorithms for various codes and
provide simulation results demonstrating their performance.
It is shown that using multiple transmit antennas and
space-time block coding provides remarkable performance at
the expense of almost no extra processing.},
Doi = {10.1109/49.753730},
Key = {fds236069}
}

@article{fds235830,
Author = {Naguib, AF and Seshádri, N and Calderbank, AR},
Title = {Increasing data rate over wireless channels: Space time
coding and signal processing for high data rate wireless
communications},
Journal = {IEEE Signal Processing Magazine},
Volume = {17},
Number = {3},
Pages = {76-92},
Year = {2000},
ISSN = {1053-5888},
url = {http://dx.doi.org/10.1109/79.841731},
Doi = {10.1109/79.841731},
Key = {fds235830}
}

@article{fds235831,
Author = {Jana, R and Al-Dhahir, N and Calderbank, R},
Title = {Distance spectrum computation for equalized MIMO multipath
Journal = {2000 IEEE Wireless Communications and Networking
Conference},
Pages = {293-297},
Year = {2000},
Abstract = {In this paper we estimate bit error probability bounds for
finite-length delay-optimised multi-input multi-output
(MIMO) equalizers. These equalizers shorten the impulse
response memory of frequency-selective MIMO channels by
minimizing the average energy of the error sequence between
the equalized MIMO channel impulse response and the target
impulse response. We answer an important question in this
paper namely, how much asymptotic loss in SNR do we expect
as a result of this shortening? A partial distance spectrum
for a 2 × 2 MIMO channel is evaluated with or without
channel shortening equalizers. The union bound is then used
to upper bound the bit error probability. Similarly, the
lower bound is computed from the squared minimum Euclidean
distance. Numerical results show that the expected loss is
in the order of 2.5 dB for realistic wireless channel
environments.},
Key = {fds235831}
}

@article{fds235833,
Author = {Calderbank, AR and Pottie, G and Seshadri, N},
Title = {Cochannel interference suppression through time/space
diversity},
Journal = {IEEE Transactions on Information Theory},
Volume = {46},
Number = {3},
Pages = {922-932},
Year = {2000},
ISSN = {0018-9448},
url = {http://dx.doi.org/10.1109/18.841171},
Abstract = {Wireless systems are subject to a time-varying and unknown a
priori combination of cochannel interference, fading, and
Gaussian noise. It is well known that multiple antennas can
provide diversity in space that allows system tradeoffs
between interference suppression and mitigation of fading.
This paper describes how to achieve these same tradeoffs
through diversity in time provided by channel coding. The
mathematical description of time diversity is identical to
that of space diversity, and what emerges is a unified
framework for signal processing. Decoding algorithms are
provided for repetition codes, rate 1/n convolutional codes,
first-order Reed-Muller codes, and a new class of linear
combination codes that provide cochannel interference
suppression. In all cases it is possible to trade
performance for complexity by choosing between joint
estimation and a novel low-complexity linear canceler
structure that treats interference as noise. This means that
a single code can be used in a variety of system
environments just by changing the processing in the
Doi = {10.1109/18.841171},
Key = {fds235833}
}

@article{fds326906,
Author = {Calderbank, R},
Title = {Abuse and disabled people: vulnerability or social
indifference?},
Journal = {Disability and Society},
Volume = {15},
Number = {3},
Pages = {521-534},
Year = {2000},
Month = {May},
url = {http://dx.doi.org/10.1080/713661966},
Doi = {10.1080/713661966},
Key = {fds326906}
}

@article{fds235832,
Author = {Naguib, AF and Calderbank, R},
Title = {Space - Time coding and signal processing for high data rate
wireless communications},
Journal = {Wireless Communications & Mobile Computing},
Volume = {1},
Number = {1},
Pages = {13-34},
Year = {2001},
ISSN = {1530-8669},
url = {http://dx.doi.org/10.1002/1530-8677(200101/03)1:1<13::AID-WCM2>3.0.CO;2-J},
Abstract = {The information capacity of wireless communication systems
can be increased dramatically by employing multiple transmit
and receive antennas [Foschini GJ, Gans MJ. On limits of
wireless communications in a fading environment when using
multiple antennas. Wireless Communications Magazine 1998; 6
311-335. Telatar E. Capacity of Multi-Antenna Gaussian
Channels, Technical Memorandum, AT&amp;T Bell Laboratories,
1995.] An effective approach to increasing data rate over
wireless channels is to employ coding techniques appropriate
to multiple transmit antennas, that is space-time coding.
Space-time codes introduce temporal and spatial correlation
into signals transmitted from different antennas, in order
to provide diversity at the receiver, and coding gain over
an uncoded system. The spatial-temporal structure of these
codes can be exploited to further increase the capacity of
wireless systems with a relatively simple receiver
structure. This paper provides an overview of space-time
coding techniques and the associated signal processing
framework. Copyright © 2001 John Wiley &amp; Sons,
Ltd.},
Doi = {10.1002/1530-8677(200101/03)1:1<13::AID-WCM2>3.0.CO;2-J},
Key = {fds235832}
}

@article{fds235834,
Author = {Stamoulis, A and Al-Dhahir, N and Calderbank, AR},
Title = {Further results on interference cancellation and space-time
block codes},
Journal = {Conference Record of the Asilomar Conference on Signals,
Systems and Computers},
Volume = {1},
Pages = {257-261},
Year = {2001},
Abstract = {Space-Time Blocks Codes (STBC) make use of a rich algebraic
structure to provide diversity gains with small decoding
complexity. In this work, we show that the rich algebraic
structure of STBC reduces the hardware and software
complexity of interference cancellation (IC) techniques.
Additionally, after the IC stage, transmitted symbols can
still be recovered with space-time diversity gains. We
present three illustrative examples of IC in wireless
networks where co-channel users employ STBC. First, we show
that any STBC that is based on an orthogonal design allows
IC of two co-channel users with simple linear processing.
Second, we show that for the Alamouti STBC, K &gt; 2 users
can be detected with simple linear processing, while still
ensuring space-time diversity gains. Third, capitalizing on
recent work on single-carrier frequency-domain STBC, we
study how the aforementioned IC schemes can be modified for
frequency-selective channels.},
Key = {fds235834}
}

@article{fds235835,
Author = {Al-Dhahir, N and Naguib, AF and Calderbank, AR},
Title = {Finite-length MIMO decision feedback equalization for
space-time block-coded signals over multipath-fading
channels},
Journal = {IEEE Transactions on Vehicular Technology},
Volume = {50},
Number = {4},
Pages = {1176-1182},
Year = {2001},
ISSN = {0018-9545},
url = {http://dx.doi.org/10.1109/25.938592},
Abstract = {A finite-length optimized-delay multi-input-multi-output
(MIMO) mean-square-error decision-feedback equalizer for
space-time block-coded transmissions over
multipath-fadingchannels is presented. Alamouti's space-time
block code with two transmit and two receive antennas on a
typical urban EDGE channel is taken as a case study. We
propose a combined equalization and decoding scheme under
the constraint of linear processing complexity (no trellis
search) at the receiver. Performance comparisons are made
with the single-transmit/single-receive antenna case and the
case of MIMO feedforward linear equalization only with no
decision feedback.},
Doi = {10.1109/25.938592},
Key = {fds235835}
}

@article{fds326905,
Author = {Calderbank, R and Sloane, NJ},
Title = {Obituary. Claude Shannon (1916-2001).},
Journal = {Nature},
Volume = {410},
Number = {6830},
Pages = {768},
Year = {2001},
Month = {April},
url = {http://dx.doi.org/10.1038/35071223},
Doi = {10.1038/35071223},
Key = {fds326905}
}

@article{fds235836,
Author = {Diggavi, SN and Al-Dhahir, N and Stamoulis, A and Calderbank,
AR},
Title = {Differential space-time coding for frequency-selective
channels},
Journal = {IEEE Communications Letters},
Volume = {6},
Number = {6},
Pages = {253-255},
Year = {2002},
ISSN = {1089-7798},
url = {http://dx.doi.org/10.1109/LCOMM.2002.1010872},
Abstract = {In this letter we introduce two space-time transmission
schemes which allow full-rate and full-diversity noncoherent
communications using two transmit antennas over fading
frequency-selective channels. The first scheme operates in
the frequency domain where it combines differential Alamouti
space-time block-coding (STBC) with OFDM. The second scheme
operates in the time domain and employs differential
time-reversal STBC to guarantee blind channel
identifiability without the need for temporal oversampling
or multiple receive antennas.},
Doi = {10.1109/LCOMM.2002.1010872},
Key = {fds235836}
}

@article{fds235837,
Author = {Al-Dhahir, N and Fragouli, C and Stamoulis, A and Younis, W and Calderbank, R},
Title = {Space-time processing for broadband wireless
access},
Journal = {IEEE Communications Magazine},
Volume = {40},
Number = {9},
Pages = {136-142},
Year = {2002},
ISSN = {0163-6804},
url = {http://dx.doi.org/10.1109/MCOM.2002.1031840},
Abstract = {We present an overview of research activities on space-time
coding for broadband wireless transmission performed at
AT&amp;T Shannon Laboratory over the past two years. The
emphasis is on physical layer modem algorithms such as
channel estimation, equalization, and interference
cancellation. However, we also discuss the impact of
space-time coding gains at the physical layer on throughput
at or above the networking layer. Furthermore, we describe a
flexible graphical user interface attached to our physical
layer simulation engine in order to explore the performance
of space-time codes under a variety of practical
transmission scenarios. Simulation results for the EDGE
cellular system and the 802.11 wireless LAN environment are
presented.},
Doi = {10.1109/MCOM.2002.1031840},
Key = {fds235837}
}

@article{fds235838,
Author = {Calderbank, AR and Daubechies, I},
Title = {The pros and cons of democracy},
Journal = {IEEE Transactions on Information Theory},
Volume = {48},
Number = {6},
Pages = {1721-1725},
Year = {2002},
ISSN = {0018-9448},
url = {http://dx.doi.org/10.1109/TIT.2002.1003852},
Abstract = {The concept of democracy was introduced in which the
individual bits in a coarsely quantized representation of a
signal were given equal weight in the approximation to the
original signal. It was proved that such democratic
representations could not achieve the same accuracy as
optimal nondemocratic schemes. Convolutional decoding was
found to be convenient in digital to analog
conversion.},
Doi = {10.1109/TIT.2002.1003852},
Key = {fds235838}
}

@article{fds235839,
Author = {Diggavi, SN and Al-Dhahir, N and Calderbank, AR},
Title = {On interference cancellation and high-rate space-time
codes},
Journal = {IEEE International Symposium on Information Theory -
Proceedings},
Pages = {238-},
Year = {2003},
Abstract = {We study the design and decoding of high-rate space-time
codes in two contexts. The first part of the paper examines
the multiple-access channel (MAC) where users employ
space-time block codes (STBC). The problem is formulated in
the context of an inter-symbol interference (ISI) channel
which occurs for transmission over frequency-selective
channels. We show that a diversity order of 2Mτ (v + 1) is
achievable at full transmission rate for each user, when we
have Mτ receive antennas, channel memory of v and an
optimal multiuser maximum-likelihood (ML) decoder is used.
In the second part, we examine high-rate space-time codes
that have a high-diversity code embedded within them. This
can also be viewed as unequal error protection codes
designed for unequal diversity order, which is the metric
suitable for fading channels.},
Key = {fds235839}
}

@article{fds235840,
Author = {Diggavi, SN and Al-Dhahir, N and Calderbank, AR},
Title = {Multiuser joint equalization and decoding of space-time
codes},
Journal = {IEEE International Conference on Communications},
Volume = {4},
Pages = {2643-2647},
Year = {2003},
Abstract = {In this paper we study the multiple-access channel where
users employ space-time block codes (STBC). The problem is
formulated in the context of an inter-symbol interference
(ISI) multiple-access channel. The algebraic structure of
the STBC is utilized to design joint interference
suppression, equalization, and decoding schemes. Each user
transmits using 2 transmit antennas and a time-reversed
space-time block code suitable for frequency-selective
channels. We first show that a diversity order of 2Mτ(ν+1)
is achievable at full transmission rate for each user, when
we have Mτ receive antennas, channel memory of ν and an
optimal multiuser maximum-likelihood (ML) decoder is used.
Due to the decoding complexity of the ML detector we study
the algebraic structure of linear multiuser detectors which
utilize the properties of the STBC. We do this both in the
transform domain (D-domain formulation) and when we impose
finite block length constraints (matrix formulation). The
receiver is designed to utilize the algebraic structure of
the codes in order to preserve the block quaternionic
structure of the equivalent channel for each
user.},
Key = {fds235840}
}

@article{fds235841,
Author = {Diggavi, SN and Al-Dhahir, N and Calderbank, AR},
Title = {Diversity-Embedded Space-Time Codes},
Journal = {Conference Record / IEEE Global Telecommunications
Conference},
Volume = {4},
Pages = {1909-1914},
Year = {2003},
Abstract = {Rate and diversity impose a fundamental trade-off in
space-time coding. High-rate space-time codes come at a cost
of lower diversity, and high reliability (diversity) implies
a lower rate. In this paper we explore a different point of
view where we design high-rate space-time codes that have a
high-diversity code embedded within them. This allows a form
of communication where the high-rate code opportunistically
takes advantage of good channel realizations whereas the
embedded high-diversity code ensures that at least part of
the information is received reliably. We explore this point
of view with design issues, along with some preliminary
progress on code constructions and some information-theoretic
considerations.},
Key = {fds235841}
}

@article{fds235842,
Author = {Diggavi, SN and Al-Dhahir, N and Calderbank, AR},
Title = {Algebraic properties of space-time block codes in
intersymbol interference multiple-access
channels},
Journal = {IEEE Transactions on Information Theory},
Volume = {49},
Number = {10},
Pages = {2403-2414},
Year = {2003},
url = {http://dx.doi.org/10.1109/TIT.2003.817833},
Abstract = {In this paper, we study the multiple-access channel where
users employ space-time block codes (STBC). The problem is
formulated in the context of an intersymbol interference
(ISI) multiple-access channel which occurs for transmission
over frequency-selective channels. The algebraic structure
of the STBC is utilized to design joint interference
suppression, equalization, and decoding schemes. Each of the
K users transmits using Mt = 2 transmit antennas and a
time-reversed STBC suitable for frequency-selective
channels. We first show that a diversity order of 2Mr (v +
1) is achievable at full transmission rate for each user,
when we have Mr receive antennas, channel memory of v, and
an optimal multiuser maximum-likelihood (ML) decoder is
used. Due to the decoding complexity of the ML detector we
study the algebraic structure of linear multiuser detectors
which utilize the properties of the STBC. We do this both in
the transform (D-domain) formulation and when we impose
finite block-length constraints (matrix formulation). The
receiver is designed to utilize the algebraic structure of
the codes in order to preserve the block quaternionic
structure of the equivalent channel for each user. We also
explore some algebraic properties of D-domain quaternionic
matrices and of quaternionic circulant block matrices that
arise in this study.},
Doi = {10.1109/TIT.2003.817833},
Key = {fds235842}
}

@article{fds235843,
Author = {Tarokh, V and Naguib, A and Seshadri, N and Calderbank,
AR},
Title = {Erratum: Space-time codes for high data rate wireless
communications: Performance criteria in the presence of
channel estimation errors, mobility, and multiple paths
(IEEE Trans. Commun. (1999) 47, (199-207))},
Journal = {IEEE Transactions on Communications},
Volume = {51},
Number = {12},
Pages = {2141-},
Year = {2003},
url = {http://dx.doi.org/10.1109/TCOMM.2003.822179},
Doi = {10.1109/TCOMM.2003.822179},
Key = {fds235843}
}

@article{fds235844,
Author = {Calderbank, AR and Diggavi, SN and Al-Dhahir, N},
Title = {Space-time signaling based on Kerdock and Delsarte-Goethals
codes},
Journal = {IEEE International Conference on Communications},
Volume = {1},
Pages = {483-487},
Year = {2004},
Abstract = {This paper designs space-time codes for standard PSK and QAM
signal constellations that have flexible rate, diversity and
require no constellation expansion. Central to this
construction are binary partitions of the PSK and QAM
constellations that appear in codes designed for the
Gaussian channel. The space-time codes presented here are
designed by separately specifying the different levels of
the binary partition in the space-time array. The individual
levels are addressed by either the binary symmetric matrices
associated with codewords in a Kerdock code or other
families of binary matrices. Binary properties of these sets
are sufficient to verify the diversity property of the
codewords in the complex domain. Larger sets of binary
symmetric matrices (such as the set used in
Delsarte-Goethals codes) are used to trade diversity
protection for increased rate.},
Key = {fds235844}
}

@article{fds235845,
Author = {Calderbank, AR and Diggavi, S and Das, S and Al-Dhahir,
N},
Title = {Construction and analysis of a new 4 × 4 orthogonal
space-time block code},
Journal = {IEEE International Symposium on Information Theory -
Proceedings},
Pages = {310-},
Year = {2004},
Abstract = {The construction and the analysis of a nonlinear 4×4 full
rate, full-diversity orthogonal space-time block codes was
discussed. The main aspect was the design, analysis and low
complexity decoding of a full rate full diversity orthogonal
STBC for four transmit antennas that was constructed by
means of 2×2 arrays over the quaternions. It was observed
that the structure of the code was a generalization of the
2×2 Alamouti code and were reduced if the quaternions in
the code were replaced by complex numbers. The results show
that the PSK signalling code has full diversity while QPSK
signalling code had no constellation expansion.},
Key = {fds235845}
}

@article{fds235846,
Author = {Diggavi, SN and Al-Dhahir, N and Stamoulis, A and Calderbank,
AR},
Title = {Great expectations: The value of spatial diversity in
wireless networks},
Journal = {Proceedings of the IEEE},
Volume = {92},
Number = {2},
Pages = {219-270},
Year = {2004},
url = {http://dx.doi.org/10.1109/JPROC.2003.821914},
Abstract = {In this paper, the effect of spatial diversity on the
throughput and reliability of wireless networks is examined.
Spatial diversity is realized through multiple independently
communication and through independently fading links in
multiuser communication. Adopting spatial diversity as a
central theme, we start by studying its information-theoretic
foundations, then we illustrate its benefits across the
physical (signal transmission/coding and receiver signal
processing) and networking (resource allocation, routing,
and applications) layers. Throughout the paper, we discuss
engineering intuition and tradeoffs, emphasizing the strong
interactions between the various network functionalities. ©
2004 IEEE.},
Doi = {10.1109/JPROC.2003.821914},
Key = {fds235846}
}

@article{fds235847,
Author = {Oggier, FE and Sloane, NJA and Diggavi, SN and Calderbank,
R},
Title = {Nonintersecting subspaces based on finite
alphabets},
Journal = {IEEE International Symposium on Information Theory -
Proceedings},
Pages = {455-},
Year = {2004},
Abstract = {Codewords were constructed subject to the constraint that
the elements of the codewords use symbols from a fixed,
small constellation. The subspaces constructed remain
nonintersecting when lifted to the complex field. The
construction shows that the codewords are nonintersecting
over the finite field. The construction gives full diversity
order when the elements of the codewords are restricted to
come from a finite field.},
Key = {fds235847}
}

@article{fds235848,
Author = {Calderbank, AR and Gilbert, A and Levchenko, K and Muthukrishnan, S and Strauss, M},
Title = {Improved range-summable random variable construction
algorithms},
Journal = {Proceedings of the Annual ACM-SIAM Symposium on Discrete
Algorithms},
Pages = {840-849},
Year = {2005},
Abstract = {Range-summable universal hash functions, also known as
range-summable random variables, are binary-valued hash
functions which can efficiently hash single values as well
as ranges of values from the domain. They have found several
applications in the area of data stream processing where
they are used to construct sketches - small-space summaries
of the input sequence. We present two new constructions of
range-summable universal hash functions on n-bit strings,
one based on Reed-Muller codes which gives k-universal
hashing using O(n log k) space arid time for point
operations and O(n 2 1og k) for range operations, and
another based on a new subcode of the second-order
Reed-Muller code, which gives 5-universal hashing using O(n)
space, O(n log 3 n) time for point operations, and O(n 3)
time for range operations. We also present a new sketch data
structure using the new hash functions which improves
several previous results.},
Key = {fds235848}
}

@article{fds235849,
Author = {Howard, SD and Moran, W and Calderbank, AR and Schmitt, HA and Savage,
CO},
Title = {Relationships between radar ambiguity and coding
theory},
Journal = {IEEE International Conference on Acoustics Speech and Signal
Processing},
Volume = {V},
Pages = {V897-V900},
Year = {2005},
ISSN = {1520-6149},
url = {http://dx.doi.org/10.1109/ICASSP.2005.1416449},
Abstract = {We investigate the theory of the finite discrete
Heisenberg-Weyl group in relation to the development of
adaptive radar. We contend that this group can form the
basis for the representation of the radar environment in
terms of operators on the space of waveforms. We also
demonstrate, following recent developments in the theory of
error correcting codes, that the finite discrete
Heisenberg-Weyl group provides a unified basis for the
construction of useful waveforms/sequences for radar,
communications and the theory of error correcting codes. ©
2005 IEEE.},
Doi = {10.1109/ICASSP.2005.1416449},
Key = {fds235849}
}

@article{fds235850,
Author = {Lee, J-W and Chiang, M and Calderbank, AR},
Title = {Distributed algorithms for optimal rate-reliability tradeoff
in networks},
Journal = {IEEE International Symposium on Information Theory -
Proceedings},
Volume = {2005},
Pages = {2246-2250},
Year = {2005},
url = {http://dx.doi.org/10.1109/ISIT.2005.1523747},
Abstract = {The current framework of network utility maximization for
distributed rate allocation assumes fixed channel code
rates. However, by adapting the physical layer channel
coding, different rate-reliability tradeoffs can be achieved
on each link and for each end user. Consider a network where
each user has a utility function that depends on both signal
quality and data rate, and each link may provide a 'fatter'
('thinner') information 'pipe' by allowing a higher (lower)
decoding error probability. We propose two distributed,
pricing-based algorithms to attain optimal rate-reliability
tradeoff, with an interpretation that each user provides its
willingness to pay for reliability to the network and the
network feeds back congestion prices to users. The proposed
algorithms converge to a tradeoff point between rate and
reliability, which is proved to be globally optimal for
codes with sufficiently large codeword lengths and user
utilities with sufficiently negative curvatures.},
Doi = {10.1109/ISIT.2005.1523747},
Key = {fds235850}
}

@article{fds235851,
Author = {Ashikhmin, A and Calderbank, AR},
Title = {Space-time reed-muller codes for noncoherent MIMO
transmission},
Journal = {IEEE International Symposium on Information Theory -
Proceedings},
Volume = {2005},
Pages = {1952-1956},
Year = {2005},
url = {http://dx.doi.org/10.1109/ISIT.2005.1523686},
Abstract = {We present a family of Space-Time codes for the noncoherent
MIMO channel. The codes are constructed via functions that
can be considered as a generalization of boolean functions
to commuting projection operators which arise in the theory
of quantum stabilizer codes. These space-time codes are
strongly related to standard binary Reed-Muller codes. In
particular, they can be decoded by adapting a decoding
algorithm for Reed-Muller codes. We show that the first
subclass of codes from this family, which we view as the
first order space-time Reed-Muller codes, allow transmission
with rates close to the MIMO noncoherent channel capacity in
the low signal to noise ratio (SNR) regime.},
Doi = {10.1109/ISIT.2005.1523686},
Key = {fds235851}
}

@article{fds235852,
Author = {Das, S and Al-Dhahir, N and Calderbank, AR},
Title = {Exploiting algebraic structure in cross-layer
design},
Journal = {2005 International Conference on Wireless Networks,
Communications and Mobile Computing},
Volume = {2},
Pages = {1466-1471},
Year = {2005},
url = {http://dx.doi.org/10.1109/WIRLES.2005.1549629},
Abstract = {We demonstrate the value of algebraic structure to
cross-layer design of multiple-antenna wireless
communication systems. At the network layer we will develop
techniques for multiple access (many to one) and broadcast
(one to many) communication where algebraic structure
enables very simple implementation. At the physical layer,
we emphasize enabling mobility and integrating receive chain
functionality (for example, channel estimation, joint
decoding and equalization) at a level of complexity that is
comparable to single-antenna systems. Algebraic structure
will make it possible to integrate these different functions
very efficiently. Another important theme in this work is
the emphasis on measuring the value of innovation at the
physical layer in terms of networking throughput or coverage
area of broadband wireless systems such as WiFi and WiMAX.
Doi = {10.1109/WIRLES.2005.1549629},
Key = {fds235852}
}

@article{fds235853,
Author = {Thangaraj, A and Dihidar, S and Calderbank, AR and McLaughlin, SW and Merolla, J-M},
Title = {On achieving capacity on the wire tap channel using LDPC
codes},
Journal = {IEEE International Symposium on Information Theory -
Proceedings},
Volume = {2005},
Pages = {1498-1502},
Year = {2005},
url = {http://dx.doi.org/10.1109/ISIT.2005.1523593},
Abstract = {We investigate the use of capacity and near-capacity
achieving LPDC codes on the wire tap channel, where the dual
conditions of reliable communications and security are
required. We show that good codes for conventional channels
(like BSC and BEC) also have interesting and useful security
properties. In this paper we show the connection between the
decoding threshold of the code and its security against
eavesdropping. We also give practical code constructions for
some special cases of the wire tap channel and show that
security (in the Shannon sense) is a function of the
decoding threshold. Some of these constructions achieve the
secrecy capacity as denned by Wyner. These codes provide
secure communications without conventional key distribution
and provide a physical-layer approach for either secure
communications or key distribution.},
Doi = {10.1109/ISIT.2005.1523593},
Key = {fds235853}
}

@article{fds235854,
Author = {Oggier, FE and Sloane, NJA and Diggavi, SN and Calderbank,
AR},
Title = {Nonintersecting subspaces based on finite
alphabets},
Journal = {IEEE Transactions on Information Theory},
Volume = {51},
Number = {12},
Pages = {4320-4325},
Year = {2005},
ISSN = {0018-9448},
url = {http://dx.doi.org/10.1109/TIT.2005.858946},
Abstract = {Two subspaces of a vector space are here called
"nonintersecting" if they meet only in the zero vector.
Motivated by the design of noncoherent multiple-antenna
communications systems, we consider the following question.
How many pairwise nonintersecting Mt-dimensional subspaces
of an m-dimensional vector space V over a field F can be
found, if the generator matrices for the subspaces may
contain only symbols from a given finite alphabet A ⊆ F?
The most important case is when F is the field of complex
numbers C; then Mt is the number of antennas. If A = F =
GF(q) it is shown that the number of nonintersecting
subspaces is at most (qm - 1)/(qMt - 1), and that this bound
can be attained if and only if m is divisible by Mt.
Furthermore, these subspaces remain nonintersecting when
"lifted" to the complex field. It follows that the finite
field case is essentially completely solved. In the case
when F = C only the case Mt = 2 is considered. It is shown
that if A is a PSK-configuration, consisting of the 2r
complex roots of unity, the number of nonintersecting planes
is at least 2r(m-2) and at most 2r(m-1)-1 (the lower bound
may in fact be the best that can be achieved. © 2005
IEEE.},
Doi = {10.1109/TIT.2005.858946},
Key = {fds235854}
}

@article{fds235772,
Author = {Tang, A and Lee, J-W and Huang, J and Chiang, M and Calderbank,
AR},
Title = {Reverse engineering MAC},
Journal = {2006 4th International Symposium on Modeling and
Optimization in Mobile, Ad Hoc and Wireless Networks, WiOpt
2006},
Year = {2006},
url = {http://dx.doi.org/10.1109/WIOPT.2006.1666466},
Abstract = {This paper reverse engineers backoff-based random-access MAC
protocols in ad-hoc networks. We show that contention
resolution algorithm in such protocols is implicitly
participating in a non-cooperative game. Each link attempts
to maximize a selfish local utility function, whose exact
shape is reverse engineered from protocol description,
through a stochastic subgradient method in which link
updates its persistence probability based on its
transmission success or failure. We prove that existence of
a Nash equilibrium is guaranteed in general. minimum amount
of backoff aggressiveness needed for uniqueness of Nash
equilibrium and convergence of best response strategy are
established as a function of user density. Convergence
properties and connection with best response strategy are
also proved for variants of stochastic-subgradient-based
dynamics of game. Together with known results in reverse
engineering TCP and BGP, this paper completes recent efforts
in reverse engineering main protocols in layers 2-4. © 2006
IEEE.},
Doi = {10.1109/WIOPT.2006.1666466},
Key = {fds235772}
}

@article{fds235855,
Author = {Howard, S and Calderbank, A and Moran, W},
Title = {The finite Heisenberg-Weyl groups in radar and
communications},
Journal = {Eurasip Journal on Advances in Signal Processing},
Volume = {2006},
Year = {2006},
ISSN = {1110-8657},
url = {http://dx.doi.org/10.1155/ASP/2006/85685},
Abstract = {We investigate the theory of the finite Heisenberg-Weylgroup
in relation to the development of adaptive radar and to
theconstruction of spreading sequences and error-correcting
codes incommunications. We contend that this group can form
the basis forthe representation of the radar environment in
terms of operatorson the space of waveforms. We also
demonstrate, following recentdevelopments in the theory of
error-correcting codes, that thefinite Heisenberg-Weyl
groups provide a unified basis for theconstruction of useful
waveforms/sequences for radar,communications, and the theory
of error-correcting codes.},
Doi = {10.1155/ASP/2006/85685},
Key = {fds235855}
}

@article{fds235856,
Author = {Lee, J-W and Chiang, M and Calderbank, AR},
Title = {Jointly optimal congestion and medium access control in ad
hoc wireless networks},
Journal = {IEEE VTS ... Vehicular Technology Conference : VTC :
[proceedings]},
Volume = {1},
Pages = {284-288},
Year = {2006},
ISSN = {1550-2252},
url = {http://dx.doi.org/10.1109/VETECS.2004.1387959},
Abstract = {We study joint end-to-end congestion control and per-link
medium access control (MAC) in ad-hoc wireless networks. We
use a network utility maximization formulation, in which by
adjusting the types of utility functions, we can accommodate
multi-class services as well as exploit the tradeoff between
efficiency and fairness of resource allocation. Despite the
inherent difficulties of non-convexity and non-separability
of the optimization problem, we show that, under
readily-verifiable sufficient conditions, we can develop a
distributed algorithm that converges to the globally and
jointly optimal rate allocation and persistence
probabilities. A key contribution is that our results can
accommodate general concave utility function rather than
just the logarithmic utility function in existing results.
Doi = {10.1109/VETECS.2004.1387959},
Key = {fds235856}
}

@article{fds235857,
Author = {Lee, J-W and Chiang, M and Calderbank, AR},
Title = {Utility-optimal medium access control: Reverse and forward
engineering},
Journal = {Proceedings - IEEE INFOCOM},
Year = {2006},
ISSN = {0743-166X},
url = {http://dx.doi.org/10.1109/INFOCOM.2006.252},
Abstract = {This paper analyzes and designs medium access control (MAC)
protocols for wireless ad-hoc networks through the network
utility maximization (NUM) framework. We first
reverse-engineer the current exponential backoff (EB) type
of MAC protocols such as the BEB (binary exponential
backoff) in the IEEE 802.11 standard through a
non-cooperative gametheoretic model. This MAC protocol is
shown to be implicitly maximizing, using a stochastic
subgradient, a selfish local utility at each link in the
form of expected net reward for successful transmission.
While the existence of a Nash equilibrium can be
established, neither convergence nor social welfare
optimality is guaranteed due to the inadequate feedback
mechanism in the EB protocol. This motivates the
forward-engineering part of the paper, where a network-wide
utility maximization problem is formulated, using a
collision and persistence probability model and aligning
selfish utility with total social welfare. By adjusting the
parameters in the utility objective functions of the NUM
problem, we can also control the tradeoff between efficiency
and fairness of radio resource allocation through a rigorous
and systematic design. We develop two distributed algorithms
to solve the MAC design NUM problem, which lead to random
access protocols that have slightly more message passing
overhead than the current EB protocol, but significant
potential for efficiency and fairness improvement. We
provide readily-verifiable sufficient conditions under which
convergence of the proposed algorithms to a global
optimality of network utility can be guaranteed, and through
numerical examples illustrate the value of the NUM approach
to the complexity-performance tradeoff in MAC design. ©
2006 IEEE.},
Doi = {10.1109/INFOCOM.2006.252},
Key = {fds235857}
}

@article{fds235858,
Author = {Chiang, M and Low, SH and Calderbank, AR and Doyle,
JC},
Title = {Layering as optimization decomposition: Framework and
examples},
Journal = {2006 IEEE Information Theory Workshop, ITW
2006},
Pages = {52-56},
Year = {2006},
Abstract = {Network protocols in layered architectures have historically
been obtained primarily on an ad-hoc basis. Recent research
has shown that network protocols may instead be holistically
analyzed and systematically designed as distributed
solutions to some global optimization problems in the form
of Network Utility Maximization (NUM), providing insight
into what they optimize and structures of the network
protocol stack. This paper presents a short survey of the
recent efforts towards a systematic understanding of
'layering' as 'optimization decomposition', where the
overall communication network is modeled by a generalized
NUM problem, each layer corresponds to a decomposed
subproblem, and the interfaces among layers are quantified
as functions of the optimization variables coordinating the
subproblems. Different decompositions lead to alternative
layering architectures. We summarize several examples of
horizontal decomposition into distributed computation and
vertical decomposition into functional modules such as
congestion control, routing, scheduling, random access,
power control, and coding. © 2006 IEEE.},
Key = {fds235858}
}

@article{fds235859,
Author = {Lee, J-W and Chiang, M and Calderbank, AR},
Title = {Network utility maximization and price-based distributed
algorithms for rate-reliability tradeoff},
Journal = {Proceedings - IEEE INFOCOM},
Year = {2006},
ISSN = {0743-166X},
url = {http://dx.doi.org/10.1109/INFOCOM.2006.110},
Abstract = {The current framework of network utility maximization for
rate allocation and its price-based algorithms assumes that
each link provides a fixed-size transmission 'pipe' and each
user's utility is a function of transmission rate only.
These assumptions break down in many practical systems,
where, by adapting the physical layer channel coding or
transmission diversity, different tradeoffs between rate and
reliability can be achieved. In network utility maximization
problems formulated in this paper, the utility for each user
depends on both transmission rate and signal quality, with
an intrinsic tradeoff between the two. Each link may also
provide a higher (lower) rate on the transmission 'pipes' by
allowing a higher (lower) decoding error probability.
Despite non-separability and nonconvexity of these
optimization problems, we propose new pricebased distributed
algorithms and prove their convergence to the globally
sufficient conditions. We first consider networks in which
the rate-reliability tradeoff is controlled by adapting
channel code rates in each link's physical layer error
correction codes, and propose two distributed algorithms
based on pricing, which respectively implement the
'integrated' and 'differentiated' policies of dynamic
ratereliability adjustment. In contrast to the classical
price-based rate control algorithms, in our algorithms each
user provides an offered price for its own reliability to
the network while the network provides congestion prices to
users. The proposed algorithms converge to a tradeoff point
between rate and reliability, which we prove to be a
globally optimal one for channel codes with sufficiently
large coding length and utilities whose curvatures are
sufficiently negative. Under these conditions, the proposed
algorithms can thus generate the Pareto optimal tradeoff
curves between rate and reliability for all the users. The
distributed algorithms and convergence proofs are extended
for wireless MIMO multi-hop networks, in which diversity and
multiplexing gains of each link are controlled to achieve
IEEE.},
Doi = {10.1109/INFOCOM.2006.110},
Key = {fds235859}
}

@article{fds235860,
Author = {Liu, J and Calderbank, AR},
Title = {The icosian code and the e8 lattice: A new 4 × 4
space-time code with non-vanishing determinant},
Journal = {IEEE International Symposium on Information Theory -
Proceedings},
Pages = {1006-1010},
Year = {2006},
url = {http://dx.doi.org/10.1109/ISIT.2006.261879},
Abstract = {This paper introduces a new full-rate, full-diversity
space-time code for 4 transmit antennas. The 4 × 4 codeword
matrix consists of four 2 × 2 Alamouti blocks with entries
from Q(i, √5), and these blocks can be viewed as
quaternions which in turn represent rotations in R3. The
Alamouti blocks that appear in a codeword are drawn from the
icosian ring consisting of all linear combinations of 120
basic rotations corresponding to symmetries of the
icosahedron. This algebraic structure is different from the
Golden code, but the complex entries are taken from a
similar underlying field. The minimum determinant is bounded
below by a constant that is independent of the signal
constellation, and the new code admits a simple decoding
scheme that makes use of a geometric correspondence between
the icosian ring and the E 8 lattice. © 2006
IEEE.},
Doi = {10.1109/ISIT.2006.261879},
Key = {fds235860}
}

@article{fds235861,
Author = {Minn, H and Li, Y and Al-Dhahir, N and Calderbank,
R},
Title = {Pilot designs for consistent frequency offset estimation in
OFDM systems},
Journal = {Conference Record - International Conference on
Communications},
Volume = {10},
Pages = {4566-4571},
Year = {2006},
ISSN = {0536-1486},
url = {http://dx.doi.org/10.1109/ICC.2006.255359},
Abstract = {This paper presents pilot designs for consistent frequency
offset estimation of OFDM systems in frequencyselective
fading channels. We describe two design approaches, namely
consistency in the probabilistic sense and absolute
consistency. Existing preambles and pilot designs in the
literature do not guarantee the absolute consistency. We
derive general criteria for both approaches, present
sufficient conditions on the pilot structures, and derive
simple pilot designs satisfying these conditions. Absolute
consistency should not be compromised in emergency-related
or other critical communication scenarios and our proposed
consistent pilot designs address this need. © 2006
IEEE.},
Doi = {10.1109/ICC.2006.255359},
Key = {fds235861}
}

@article{fds235862,
Author = {Chul, J and Calderbank, AR},
Title = {Effective coding gain for space-time codes},
Journal = {IEEE International Symposium on Information Theory -
Proceedings},
Pages = {252-256},
Year = {2006},
url = {http://dx.doi.org/10.1109/ISIT.2006.261844},
Abstract = {The performance of space-time codes is evaluated in terms of
diversity gain and coding gain, two measures which describe
the worst-case pairwise error probability between codewords
at high signal-to-noise ratio (SNR). We introduce the
concept of effective coding gain to provide an estimate on
the bit error rate (BER) at low-to-moderate SNR. This
concept connects the number of nearest neighbours with
degradation in error performance. We demonstrate the value
of the new concept through analysis of space-time block
codes for the quasi-static Rayleigh fading channel. © 2006
IEEE.},
Doi = {10.1109/ISIT.2006.261844},
Key = {fds235862}
}

@article{fds235863,
Author = {Das, S and Al-Dhahir, N and Calderbank, R and Chui,
J},
Title = {New full-diversity high-rate space-time block codes based on
selective power scaling},
Journal = {European Signal Processing Conference},
Year = {2006},
ISSN = {2219-5491},
Abstract = {We design a new rate-5/4 full-diversity orthogonal STBC for
QPSK and 2 transmit antennas by enlarging the signalling set
from the set of quaternions used in the Alamouti [1] code.
Selective power scaling of information symbols is used to
guarantee full-diversity while maximizing the coding gain
and minimizing the transmitted signal peak-to-minimum power
ratio. The optimum power scaling factor is derived using two
equivalent criteria and shown to outperform schemes based on
only constellation rotation while still enjoying a
lowcomplexity ML decoding algorithm. Extensions to the case
of 4 transmit antennas are reported in [4].},
Key = {fds235863}
}

@article{fds235864,
Author = {Calderbank, AR and Howard, SD and Moran, W and Pezeshki, A and Zoltowski, M},
Title = {Instantaneous radar polarimetry with multiple
dually-polarized antennas},
Journal = {Conference Record of the Asilomar Conference on Signals,
Systems and Computers},
Pages = {757-761},
Year = {2006},
ISSN = {1058-6393},
url = {http://dx.doi.org/10.1109/ACSSC.2006.354850},
Abstract = {Fully Polarimetric radar systems are capable of
simultaneously transmitting and receiving in two orthogonal
polarizations. Instantaneous radar polarimetry exploits both
polarization modes of a dually-polarized radar transmitter
and receiver on a pulse by pulse basis, and can improve the
radar detection performance and suppress range sidelobes. In
this paper, we extend the use of instantaneous radar
polarimetry for radar systems with multiple dually-polarized
transmit and receive antennas. Alamouti signal processing is
used to coordinate transmission of Golay pairs of phase
codes waveforms across polarizations and multiple antennas.
The integration of multi-antenna signal processing with
instantaneous radar polarimetry can further improve the
detection performance, at a computational cost comparable to
single channel matched filtering.},
Doi = {10.1109/ACSSC.2006.354850},
Key = {fds235864}
}

@article{fds235865,
Author = {Das, S and Al-Dhahir, N and Calderbank, R},
Title = {Novel full-diversity high-rate STBC for 2 and 4 transmit
antennas},
Journal = {IEEE Communications Letters},
Volume = {10},
Number = {3},
Pages = {171-173},
Year = {2006},
ISSN = {1089-7798},
url = {http://dx.doi.org/10.1109/LCOMM.2006.1603374},
Abstract = {We design a new rate-5/4 full-diversity orthogonal
space-time block code (STBC) for QPSK and 2 transmit
antennas (TX) by enlarging the signalling set from the set
of quaternions used in the Alamouti [1] code. Selective
power scaling of information symbols is used to guarantee
full-diversity while maximizing the coding gain (CG) and
minimizing the transmitted signal peak-to-minimum power
ratio (PMPR). The optimum power scaling factor is derived
analytically and shown to outperform schemes based only on
constellation rotation while still enjoying a low-complexity
maximum likelihood (ML) decoding algorithm. Finally, we
extend our designs to the case of 4 TX by enlarging the set
of Quasi-Orthogonal STBC with power scaling. Extensions to
general M-PSK constellations are straightforward. © 2006
IEEE.},
Doi = {10.1109/LCOMM.2006.1603374},
Key = {fds235865}
}

@article{fds235866,
Author = {Lee, J-W and Chiang, M and Calderbank, AR},
Title = {Jointly optimal congestion and contention control based on
network utility maximization},
Journal = {IEEE Communications Letters},
Volume = {10},
Number = {3},
Pages = {216-218},
Year = {2006},
ISSN = {1089-7798},
url = {http://dx.doi.org/10.1109/LCOMM.2006.1603389},
Abstract = {We study joint end-to-end congestion control and per-link
medium access control (MAC) in ad-hoc networks. We use a
network utility maximization formulation, in which by
adjusting the types of utility functions, we can accommodate
multi-class services as well as exploit the tradeoff between
efficiency and fairness of resource allocation. Despite the
inherent difficulties of non-convexity and non-separability
of the optimization problem, we show that, with
readily-verifiable sufficient conditions, we can develop a
distributed algorithm that converges to the globally and
jointly optimal rate allocation and persistence
probabilities. © 2006 IEEE.},
Doi = {10.1109/LCOMM.2006.1603389},
Key = {fds235866}
}

@article{fds235867,
Author = {Lee, J-W and Chiang, M and Calderbank, AR},
Title = {Price-based distributed algorithms for rate-reliability
tradeoff in network utility maximization},
Journal = {IEEE Journal on Selected Areas in Communications},
Volume = {24},
Number = {5},
Pages = {962-976},
Year = {2006},
ISSN = {0733-8716},
url = {http://dx.doi.org/10.1109/JSAC.2006.872877},
Abstract = {The current framework of network utility maximization for
rate allocation and its price-based algorithms assumes that
each link provides a fixed-size transmission "pipe" and each
user's utility is a function of transmission rate only.
These assumptions break down in many practical systems,
where, by adapting the physical layer channel coding or
transmission diversity, different tradeoffs between rate and
reliability can be achieved. In network utility maximization
problems formulated in this paper, the utility for each user
depends on both transmission rate and signal quality, with
an intrinsic tradeoff between the two. Each link may also
provide a higher (or lower) rate on the transmission "pipes"
by allowing a higher (or lower) decoding error probability.
Despite non-separability and nonconvexity of these
optimization problems, we propose new price-based
distributed algorithms and prove their convergence to the
globally optimal rate-reliability tradeoff under
readily-verifiable sufficient conditions. We first consider
networks in which the rate-reliability tradeoff is
controlled by adapting channel code rates in each link's
physical-layer error correction codes, and propose two
distributed algorithms based on pricing, which respectively
implement the "integrated" and "differentiated" policies of
dynamic rate-reliability adjustment. In contrast to the
classical price-based rate control algorithms, in our
algorithms, each user provides an offered price for its own
reliability to the network, while the network provides
congestion prices to users. The proposed algorithms converge
to a tradeoff point between rate and reliability, which we
prove to be a globally optimal one for channel codes with
sufficiently large coding length and utilities whose
curvatures are sufficiently negative. Under these
conditions, the proposed algorithms can thus generate the
Pareto optimal tradeoff curves between rate and reliability
for all the users. In addition, the distributed algorithms
and convergence proofs are extended for wireless
multiple-inpit-multiple-output multihop networks, in which
diversity and multiplexing gains of each link are controlled
to achieve the optimal rate-reliability tradeoff. Numerical
examples confirm that there can be significant enhancement
of the network utility by distributively trading-off rate
and reliability, even when only some of the links can
implement dynamic reliability. © 2006 IEEE.},
Doi = {10.1109/JSAC.2006.872877},
Key = {fds235867}
}

@article{fds235741,
Author = {Calderbank, AR and Naguib, AF},
Title = {Introduction to space-time codes},
Volume = {9780521851053},
Pages = {133-153},
Year = {2006},
Month = {January},
url = {http://dx.doi.org/10.1017/CBO9780511616815.008},
Abstract = {© Cambridge University Press 2006. Introduction
Information-theoretic analysis by Foschini (1996) and by
Telatar (1999) shows that multiple antennas at the
transmitter and receiver enable very high rate wireless
communication. Space-time codes, introduced by Tarokh.
(1998), improve the reliability of communication over fading
channels by correlating signals across different transmit
antennas. Design criteria developed for the high-SNR regime
in Tarokh. (1998) and Guey. (1999) are presented in Section
7.3 from the perspective of typical error events (following
the exposition by Tse and Viswanath (2005)). Techniques for
multiple access and broadcast communication are described
very briefly in Sections 7.9 and 7.10, where algebraic
structure enables simple implementation. The emphasis
throughout is on low cost, low complexity mobile receivers.
Section 7.2 provides a description of set partitioning,
which was developed by Ungerboeck (1982) as the basis of
code design for the additive white Gaussian noise (AWGN)
channel. The importance of set partitioning to code design
for the AWGN channel is that it provides a lower bound on
squared Euclidean distance between signals that depends only
on the binary sum of signal labels. Section 7.9 describes
the importance of set partitioning to code design for
wireless channels, where it provides a mechanism for
translating constraints in the binary domain into lower
bounds on diversity protection in the complex domain.
Section 7.4 describes space-time trellis codes, starting
from simple delay diversity, and then using intuition about
the product distance to realize additional coding
gain.},
Doi = {10.1017/CBO9780511616815.008},
Key = {fds235741}
}

@article{fds235742,
Author = {Naguib, AF and Calderbank, AR},
Title = {Diversity in wireless systems},
Volume = {9780521851053},
Pages = {44-65},
Year = {2006},
Month = {January},
url = {http://dx.doi.org/10.1017/CBO9780511616815.004},
Abstract = {© Cambridge University Press 2006. Introduction The main
impairment in wireless channels is fading or random
fluctuation of the signal level. This signal fluctuation
happens across time, frequency, and space. Diversity
techniques provide the receiver with multiple independent
looks at the signal to improve reception. Each one of those
independent looks is considered a diversity branch. The
probability that all diversity branches will fade at the
same time goes down as the number of branches increases.
Hence, with a high probability, there will be at least one
branch or link with a good signal such that the transmitted
data can be detected reliably. Wireless channels are, in
general, characterized by frequency-selective multipath
propagation, Doppler-induced time-selective fading, and
spaceselective fading. An emitted signal propagating through
the wireless channel is reflected and scattered from a large
number of scatterers, thereby arriving at the receiver
through different paths and hence arriving at different
times. This results in the time dispersion of the
transmitted signal. A measure of this dispersion is called
the channel delay spread Tmax. The coherence bandwidth of
the channel Bc ≈ l/Tmax measures the frequency bandwidth
over which the propagation channel remains correlated.
Therefore, a propagation channel with a small delay spread
will have a large coherence bandwidth, i.e., the channel
frequency response will remain correlated over a large
bandwidth, and vice versa. In addition, transmitter and
receiver mobility as well as changes in the propagation
medium induce time variations in the propagation
channel.},
Doi = {10.1017/CBO9780511616815.004},
Key = {fds235742}
}

@article{fds235769,
Author = {Calderbank, R},
Title = {Technology as driver of change in telecommunications},
Pages = {69-86},
Year = {2006},
Month = {January},
url = {http://dx.doi.org/10.1007/3-540-32556-5_4},
Doi = {10.1007/3-540-32556-5_4},
Key = {fds235769}
}

@article{fds235868,
Author = {Sira, SP and Cochran, D and Papandreou-Suppappola, A and Morrell, D and Moran, B and Howards, S and Calderbank, R},
Title = {Improving detection in sea clutter using waveform
scheduling},
Journal = {IEEE International Conference on Acoustics Speech and Signal
Processing},
Volume = {3},
Pages = {III1241-III1244},
Year = {2007},
ISSN = {1520-6149},
url = {http://dx.doi.org/10.1109/ICASSP.2007.367068},
Abstract = {In this paper, we propose a method to exploit waveform
agility in modern radars to improve performance in the
challenging task of detecting small targets on the ocean
surface in heavy clutter. The approach exploits the
compound-Gaussian model for sea clutter returns to achieve
clutter suppression by forming an orthogonal projection of
the received signal into the clutter subspace. Waveform
scheduling is then performed by incorporating the
information about the clutter into the design of the next
transmitted waveform. A simulation study demonstrates the
effectiveness of our approach. © 2007 IEEE.},
Doi = {10.1109/ICASSP.2007.367068},
Key = {fds235868}
}

@article{fds235869,
Author = {Li, Y and Chiang, M and Calderbank, AR and Diggavi,
SN},
Title = {Optimal rate-reliability-delay tradeoff in networks with
Journal = {Proceedings - IEEE INFOCOM},
Pages = {526-534},
Year = {2007},
ISSN = {0743-166X},
url = {http://dx.doi.org/10.1109/INFCOM.2007.68},
Abstract = {Networks need to accommodate diverse applications with
different Quality-of-Service (QoS) requirements. New ideas
at the physical layer are being developed for this purpose,
such as diversity embedded coding, which is a technique that
combines high rates with high reliability. We address the
problem of how to fully utilize different rate-reliability
characteristics at the physical layer to support different
types of traffic over a network and to jointly maximize
their utilities. We set up a new framework based on utility
maximization for networks with composite links, meaning that
each link consists of sub-links that can attain different
rate-reliability characteristics simultaneously. We
incorporate delay, in addition to rate and reliability, into
the utility functions. To accommodate different types of
traffic, we propose distributed algorithms for the optimal
rate-reliability-delay tradeoff based on capacity division
and priority queueing. Numerical results show that compared
with traditional codes, the new codes can provide higher
network utilities for all traffic types simultaneously. The
results also show that priority queueing achieves higher
network utility than capacity division. © 2007
IEEE.},
Doi = {10.1109/INFCOM.2007.68},
Key = {fds235869}
}

@article{fds235870,
Author = {Xu, D and Li, Y and Chiang, M and Calderbank, AR},
Title = {Optimal provisioning of elastic service availability},
Journal = {Proceedings - IEEE INFOCOM},
Pages = {1505-1513},
Year = {2007},
ISSN = {0743-166X},
url = {http://dx.doi.org/10.1109/INFCOM.2007.177},
Abstract = {Service availability is one of the most closely scrutinized
metrics in offering network services. The network vendor can
earn more revenue from the customers by guaranteeing higher
service availability at the cost of higher operational
expense. It is important to cost-effectively provision a
managed and differentiated network with various service
availability guarantees under a unified platform. In this
paper, we establish the framework of provisioning elastic
service availability through network utility maximization,
and propose an optimal and distributed solution using
differentiated failure recovery schemes. First, we develop a
utility function with configurable parameters to represent
the satisfaction perceived by a user upon service
availability as well as its allowed source rate. Second,
adopting Quality of Protection [1] and shared path
protection, we transform optimal provisioning of elastic
service availability into a convex optimization problem. The
desirable service availability and source rate for each user
can be achieved using a price-based distributed algorithm.
Finally, we numerically show the tradeoff between the
throughput and the service availability obtained by users in
various network topologies. Several quantitative
observations are made from this investigation. For example,
indiscriminately provisioning service availabilities for
different kinds of users within one network leads to
noteworthy sub-optimality in total network utility. The
profile of bandwidth usage also illustrates that
provisioning high service availability exclusively for
critical applications leads to significant waste in
bandwidth resource. © 2007 IEEE.},
Doi = {10.1109/INFCOM.2007.177},
Key = {fds235870}
}

@article{fds235871,
Author = {Chiang, M and Low, SH and Calderbank, AR and Doyle,
JC},
Title = {Layering as optimization decomposition: Questions and
Journal = {Proceedings - IEEE Military Communications Conference
MILCOM},
Year = {2007},
url = {http://dx.doi.org/10.1109/MILCOM.2006.302293},
Abstract = {Network protocols in layered architectures have historically
been obtained on an ad-hoc basis, and much of the recent
cross-layer designs are conducted through piecemeal
approaches. Network protocols may instead be holistically
analyzed and systematically designed as distributed
solutions to some global optimization problems in the form
of generalized Network Utility Maximization (NUM), providing
insight on what they optimize and on the structures of
network protocol stacks. In the form of 10 Questions and
Answers, this paper presents a short survey of the recent
efforts towards a systematic understanding of "layering" as
"optimization decomposition". The overall communication
network is modeled by a generalized NUM problem, each layer
corresponds to a decomposed subproblem, and the interfaces
among layers are quantified as functions of the optimization
variables coordinating the subproblems. Furthermore, there
are many alternative decompositions, each leading to a
different layering architecture. Industry adoption of this
unifying framework has also started. Here we summarize the
current status of horizontal decomposition into distributed
computation and vertical decomposition into functional
modules such as congestion control, routing, scheduling,
random access, power control, and coding. We also discuss
under-explored future research directions in this area. More
importantly than proposing any particular crosslayer design,
this framework is working towards a mathematical foundation
of network architectures and the design process of
modularization.},
Doi = {10.1109/MILCOM.2006.302293},
Key = {fds235871}
}

@article{fds235872,
Author = {Li, Y and Minn, H and Al-Dhahir, N and Calderbank,
R},
Title = {Robust pilot design for consistent carrier frequency offset
estimation},
Journal = {Proceedings - IEEE Military Communications Conference
MILCOM},
Year = {2007},
url = {http://dx.doi.org/10.1109/MILCOM.2006.302204},
Abstract = {Consistent pilot designs [6] for carrier frequency offset
(CFO) estimation eliminate ambiguity in the noise-free
estimation metric trajectory regardless of the channel
impulse response. Their importance is more pronounced in
emergency and disaster situations since an inconsistent CFO
estimate will result in a link failure. The CFO estimation
performances of distinct consistent pilot designs can be
quite different at moderate or low SNR due to different
statistics of outlier which also yields a link failure. In
this paper, we develop novel pilot designs that provide both
consistency and robustness against outliers. We also propose
new generalized pilot designs that yield consistency over
any arbitrary but fixed CFO estimation range and that
include our previous consistent pilot designs in [6] as a
special case which provides consistency over the maximum CFO
estimation range (half of the sampling rate). Our new
consistent pilot designs facilitate more flexible and
economical implementation while our robust pilot designs
enable wireless links with less outage and better
resilience.},
Doi = {10.1109/MILCOM.2006.302204},
Key = {fds235872}
}

@article{fds235873,
Author = {Chiang, M and Low, SH and Calderbank, AR and Doyle,
JC},
Title = {Layering as optimization decomposition: Current status and
open issues},
Journal = {2006 IEEE Conference on Information Sciences and Systems,
CISS 2006 - Proceedings},
Pages = {355-362},
Year = {2007},
url = {http://dx.doi.org/10.1109/CISS.2006.286492},
Abstract = {Network protocols in layered architectures have historically
been obtained on an ad-hoc basis, and much of the recent
cross-layer designs are conducted through piecemeal
approaches. Network protocols may instead be holistically
analyzed and systematically designed as distributed
solutions to some global optimization problems in the form
of generalized Network Utility Maximization (NUM), providing
insight on what they optimize and structures of the network
protocol stack. This paper presents a short survey of the
recent efforts towards a systematic understanding of
"layering" as "optimization decomposition", where the
overall communication network is modeled by a generalized
NUM problem, each layer corresponds to a decomposed
subproblem, and the interfaces among layers are quantified
as functions of the optimization variables coordinating the
subproblems. Furthermore, there are many alternative
decompositions, each leading to a different layering
architecture. Industry adoption of this unifying framework
has also started. Here we summarize the current status of
horizontal decomposition into distributed computation and
vertical decomposition into functional modules such as
congestion control, routing, scheduling, random access,
power control, and coding. Key messages and methodologies
arising out of many recent work are listed. Then we present
a list of challenging open issues in this area and the
initial progress made on some of them. © 2006
IEEE.},
Doi = {10.1109/CISS.2006.286492},
Key = {fds235873}
}

@article{fds235874,
Author = {Li, Y and Chiang, M and Calderbank, AR},
Title = {Congestion control in networks with delay sensitive
traffic},
Journal = {GLOBECOM - IEEE Global Telecommunications
Conference},
Pages = {2746-2751},
Year = {2007},
url = {http://dx.doi.org/10.1109/GLOCOM.2007.520},
Abstract = {We study the congestion control in a network where the users
may have different types of traffic, such as the traffic
with fixed/variable rate, delay sensitive/insensitive, etc.
To reflect the different requirements on delay by different
applications, explicit terms of delay are added to the
utility function. We analyze the essential dynamics for the
network utility maximization (NUM) with the new utility
functions. Compared with the basic NUM where the utility
function is only a function of rate, the dynamics for link
price is now related to the delay term added in the utility
function. The analysis is applied to the system with voice
and data traffic, and distributed algorithms are proposed to
allocate the resource such that the utility of voice and
data is jointly optimized. The numerical results show that
by the new price dynamics, we can accomplish optimal
congestion control for users with delay sensitive/insensitive
traffic in a network. In particular, in a network with data
and voice traffic with priority queueing, the algorithm can
lead the network to achieve higher quality of voice traffic
and higher throughput of data traffic, with the sacrifice of
the packet delay of data traffic. © 2007
IEEE.},
Doi = {10.1109/GLOCOM.2007.520},
Key = {fds235874}
}

@article{fds235875,
Author = {Howard, SD and Sirianunpiboon, S and Calderbank,
AR},
Title = {Fast decoding of the golden code by diophantine
approximation},
Journal = {2007 IEEE Information Theory Workshop, ITW 2007,
Proceedings},
Pages = {590-594},
Year = {2007},
url = {http://dx.doi.org/10.1109/ITW.2007.4313140},
Abstract = {The Golden Code is incorporated in the IEEE 802.16 standard
and is representative of a large class of space-time codes
where performance is determined by the difficulty of solving
an associated Diophantine approximation problem. This paper
develops a new approach to coherent decoding where channel
state information is used to select from a plurality of
zero-forcing decoders. The selection is made to maximize
effective signal to noise ratio and the underlying
Diophantine geometry guarantees that at least one of the
available choices is good. The approach is described in
detail for the important special case of the Golden code but
it applies to a larger class of space-time codes where it
provides a means of avoiding the uncertainties and
implementation complexity associated with sphere decoding.
In particular it extends battery life at the mobile terminal
by eliminating the need for a second receive antenna.
Simulation results for the Golden Code show performance
within 2 dB of full maximum-likelihood decoding with worst
case complexity that is quadratic in the size of the QAM
signal constellation. © 2007 IEEE.},
Doi = {10.1109/ITW.2007.4313140},
Key = {fds235875}
}

@article{fds235876,
Author = {Calderbank, R and Kobayashi, H},
Title = {Greetings},
Journal = {2006 IEEE Conference on Information Sciences and Systems,
CISS 2006 - Proceedings},
Pages = {iii},
Year = {2007},
url = {http://dx.doi.org/10.1109/CISS.2006.286417},
Doi = {10.1109/CISS.2006.286417},
Key = {fds235876}
}

@article{fds235877,
Author = {Dusad, S and Diggavi, SN and Calderbank, AR},
Title = {Cross layer utility of diversity embedded
codes},
Journal = {2006 IEEE Conference on Information Sciences and Systems,
CISS 2006 - Proceedings},
Pages = {795-800},
Year = {2007},
url = {http://dx.doi.org/10.1109/CISS.2006.286575},
Abstract = {Diversity embedded codes are opportunistic codes designed
for the wireless fading channel. They are high-rate
space-time codes which have embedded within them a
high-diversity (low rate) code. In this paper, we focus on
the application of diversity embedded code to transmission
of images over wireless channels. We match the diversity
embedded code with a hierarchical (layered) source coder and
quantify the image quality as compared to a single-layer
space-time code. These preliminary results suggest that
diversity embedded codes might be the right physical layer
functionality required for wireless multimedia transmission.
Doi = {10.1109/CISS.2006.286575},
Key = {fds235877}
}

@article{fds235878,
Author = {Aggarwal, V and Bennatan, A and Calderbank, AR},
Title = {On maximizing coverage in Gaussian relay
networks},
Journal = {Proceedings of the 2007 IEEE Information Theory Workshop on
Information Theory for Wireless Networks,
ITW},
Pages = {37-41},
Year = {2007},
url = {http://dx.doi.org/10.1109/ITWITWN.2007.4318027},
Abstract = {Results for Gaussian relay channels typically focus on
maximizing transmission rates for given locations of the
source, relay and destination. We consider an alternative
approach, focusing on maximizing coverage for a given rate.
This novel perspective enables treatment of the relay
location as a design parameter, producing an extra degree of
freedom that may be optimized. Focusing on coverage, we
evaluate existing approaches, like decode and forward (DF),
compress and forward (CF) and compare them with upper
bounds. In the process, we obtain some surprising insights
on the performance of these approaches. ©2007
IEEE.},
Doi = {10.1109/ITWITWN.2007.4318027},
Key = {fds235878}
}

@article{fds235879,
Author = {Sirianunpiboon, S and Howard, SD and Calderbank,
AR},
Title = {Diversity gains across line of sight and rich scattering
environments from space-polarization-time
codes},
Journal = {Proceedings of the 2007 IEEE Information Theory Workshop on
Information Theory for Wireless Networks,
ITW},
Pages = {1-5},
Year = {2007},
url = {http://dx.doi.org/10.1109/ITWITWN.2007.4318020},
Abstract = {Space-time codes built out of Alamouti components have been
adopted in wireless standards such as UMTS, IEEE 802.11n and
IEEE 802.16 where they facilitate higher data rates through
multiplexing of parallel data streams and the addition of
two or more antennas at the receiver that perform
interference cancellation. This paper provides new
theoretical insight into an algorithm for interference
cancellation through a Bayesian analysis that expresses
performance as a function of SNR in terms of the "angles"
between different space-time coded data streams. Our
approach provides insights into the coupling of channel
coding to spatial and polarization degrees of freedom.
Doi = {10.1109/ITWITWN.2007.4318020},
Key = {fds235879}
}

@article{fds235880,
Author = {Pezeshki, A and Calderbank, R and Howard, SD and Moran,
W},
Title = {Doppler resilient golay complementary pairs for
Journal = {IEEE Workshop on Statistical Signal Processing
Proceedings},
Pages = {483-487},
Year = {2007},
url = {http://dx.doi.org/10.1109/SSP.2007.4301305},
Abstract = {We present a systematic way of constructing a Doppler
resilient sequence of Golay complementary waveforms for
radar, for which the composite ambiguity function maintains
ideal shape at small Doppler shifts. The idea is to
determine a sequence of Golay pairs that annihilates the
low-order terms of the Taylor expansion of the composite
ambiguity function. The Prouhet-Thue-Morse sequence plays a
key role in the construction of Doppler resilient sequences
of Golay pairs. We extend this construction to multiple
dimensions. In particular, we consider radar polarimetry,
where the dimensions are realized by two orthogonal
polarizations. We determine a sequence of two-by-two
Alamouti matrices, where the entries involve Golay pairs and
for which the matrix-valued composite ambiguity function
vanishes at small Doppler shifts. ©2007
IEEE.},
Doi = {10.1109/SSP.2007.4301305},
Key = {fds235880}
}

@article{fds235881,
Author = {Suvorova, S and Howard, S and Moran, B and Calderbank, R and Pezeshki,
A},
Title = {Doppler resilience, reed-müller codes and complementary
waveforms},
Journal = {Conference Record of the Asilomar Conference on Signals,
Systems and Computers},
Pages = {1839-1843},
Year = {2007},
ISSN = {1058-6393},
url = {http://dx.doi.org/10.1109/ACSSC.2007.4487553},
Abstract = {While the use of complementary waveforms has been considered
as a technique for providing essentially perfect range
sidelobe performance in radar systems, its lack of
resilience to Doppler is often cited as a reason not to
deploy it. This work describes and examines techniques both
for providing Doppler resilience as well as tailoring
Doppler performance to specific aims. The Doppler
performance can be varied by suitably changing the order of
transmission of multiple sets of complementary waveforms. We
propose a method which improves Doppler performance
significantly in specific Doppler ranges by arranging the
transmission of multiple copies of complementary waveforms
according to a suitable choice from the first order
Reed-Müller codes. We provide both a theoretical analysis
and computer simulations of the Doppler response of waveform
sequences constructed in this way. © 2007
IEEE.},
Doi = {10.1109/ACSSC.2007.4487553},
Key = {fds235881}
}

@article{fds235882,
Author = {Dusad, S and Diggavi, SN and Calderbank, AR},
Title = {Rank distance codes for ISI channels},
Journal = {Proceedings of the 2007 IEEE Information Theory Workshop on
Information Theory for Wireless Networks,
ITW},
Pages = {32-36},
Year = {2007},
url = {http://dx.doi.org/10.1109/ITWITWN.2007.4318026},
Abstract = {Designs for transmit alphabet constrained space-time codes
naturally lead to questions about the design of rank
distance codes. Recently, diversity embedded multi-level
space-time codes for flat fading channels have been designed
by using sets of binary matrices with rank distance
guarantees over the binary field and mapping them onto QAM
and PSK constellations. In this paper we give the design of
diversity embedded space-time codes for fading Inter-Symbol
Interference (ISI) channels with provable rank distance
guarantees. In the process of doing so we also get a
(asymptotic) characterization of the rate-diversity
trade-off for multiple antenna fading ISI channels when
there is a fixed transmit alphabet constraint. The key idea
is to construct and analyze properties of binary matrices
with the particular structure induced by ISI channels.
Doi = {10.1109/ITWITWN.2007.4318026},
Key = {fds235882}
}

@article{fds235883,
Author = {Chiang, M and Low, SH and Calderbank, AR and Doyle,
JC},
Title = {Layering as optimization decomposition: A mathematical
theory of network architectures},
Journal = {Proceedings of the Institute of Electrical and Electronics
Engineers (IEEE)},
Volume = {95},
Number = {1},
Pages = {255-312},
Year = {2007},
ISSN = {0018-9219},
url = {http://dx.doi.org/10.1109/JPROC.2006.887322},
Abstract = {Network protocols in layered architectures have historically
been obtained on an ad hoc basis, and many of the recent
cross-layer designs are also conducted through piecemeal
approaches. Network protocol stacks may instead be
holistically analyzed and systematically designed as
distributed solutions to some global optimization problems.
This paper presents a survey of the recent efforts towards a
systematic understanding of layering as optimization
decomposition, where the overall communication network is
modeled by a generalized network utility maximization
problem, each layer corresponds to a decomposed subproblem,
and the interfaces among layers are quantified as functions
of the optimization variables coordinating the subproblems.
There can be many alternative decompositions, leading to a
choice of different layering architectures. This paper
surveys the current status of horizontal decomposition into
distributed computation, and vertical decomposition into
functional modules such as congestion control, routing,
scheduling, random access, power control, and channel
coding. Key messages and methods arising from many recent
works are summarized, and open issues discussed. Through
case studies, it is illustrated how layering as Optimization
Decomposition provides a common language to think about
modularization in the face of complex, networked
interactions, a unifying, top-down approach to design
protocol stacks, and a mathematical theory of network
architectures © 2006 IEEE.},
Doi = {10.1109/JPROC.2006.887322},
Key = {fds235883}
}

@article{fds235884,
Author = {Aggarwal, V and Calderbank, AR},
Title = {Boolean functions, projection operators and quantum error
correcting codes},
Journal = {IEEE International Symposium on Information Theory -
Proceedings},
Pages = {2091-2095},
Year = {2007},
url = {http://dx.doi.org/10.1109/ISIT.2007.4557529},
Abstract = {This paper describes a common mathematical framework for the
design of additive and non-additive Quantum Error Correcting
Codes. It is based on a correspondence between boolean
functions and projection operators. The new framework
extends to operator quantum error correcting codes. ©2007
IEEE.},
Doi = {10.1109/ISIT.2007.4557529},
Key = {fds235884}
}

@article{fds235885,
Author = {Howard, SD and Calderbank, AR and Moran, W},
Title = {A simple signal processing architecture for instantaneous
Journal = {IEEE Transactions on Information Theory},
Volume = {53},
Number = {4},
Pages = {1282-1289},
Year = {2007},
ISSN = {0018-9448},
url = {http://dx.doi.org/10.1109/TIT.2007.892809},
Abstract = {This paper describes a new radar primitive that enables
instantaneous radar polarimetry at essentially no increase
in signal processing complexity. This primitive coordinates
transmission of distinct waveforms on orthogonal
polarizations and applies a unitary matched filter bank on
receive. This avoids the information loss inherent in
single-channel matched filters. A further advantage of this
scheme is the elimination of range sidelobes. © 2007
IEEE.},
Doi = {10.1109/TIT.2007.892809},
Key = {fds235885}
}

@article{fds235886,
Author = {Li, Y and Minn, H and Al-Dhahir, N and Calderbank,
AR},
Title = {Pilot designs for consistent frequency-offset estimation in
OFDM systems},
Journal = {IEEE Transactions on Communications},
Volume = {55},
Number = {5},
Pages = {864-877},
Year = {2007},
ISSN = {0090-6778},
url = {http://dx.doi.org/10.1109/TCOMM.2007.896105},
Abstract = {This paper presents pilot designs for consistent
frequency-offset estimation of orthogonal frequency-division
multiplexing systems in frequency-selective fading channels.
We describe two design approaches, namely, consistency in
the probabilistic sense and absolute consistency. Existing
preambles and pilot designs in the literature do not
guarantee the absolute consistency. We derive general
criteria for both approaches, present sufficient conditions
on the pilot structures over the maximum carrier frequency
offset (CFO) estimation range (half of the sampling rate),
and derive simple pilot designs satisfying these conditions.
We also extend the sufficient conditions to any arbitrary
but fixed CFO estimation range, and present some generalized
design patterns. Furthermore, the CFO estimation
performances of distinct consistent pilot designs can be
quite different at moderate or low signal-to-noise ratio
(SNR) due to different statistics of outliers which also
yields a link failure. We develop efficient pilot-design
criteria that provide both consistency and robustness
against outliers at moderate-to-low SNR. Our consistent
pilot designs facilitate flexible and economical
implementation, while our robust pilot designs enable
wireless links with less outage and better resilience. ©
2007 IEEE.},
Doi = {10.1109/TCOMM.2007.896105},
Key = {fds235886}
}

@article{fds235887,
Author = {Sira, SP and Cochran, D and Papandreou-Suppappola, A and Morrell, D and Moran, W and Howard, SD and Calderbank, R},
Title = {Adaptive waveform design for improved detection of low-RCS
targets in heavy sea clutter},
Journal = {IEEE Journal of Selected Topics in Signal
Processing},
Volume = {1},
Number = {1},
Pages = {56-66},
Year = {2007},
ISSN = {1932-4553},
url = {http://dx.doi.org/10.1109/JSTSP.2007.897048},
Abstract = {The dynamic adaptation of waveforms for transmission by
active radar has been facilitated by the availability of
waveform-agile sensors. In this paper, we propose a method
to employ waveform agility to improve the detection of low
radar-cross section (RCS) targets on the ocean surface that
present low signal-to-clutter ratios due to high sea states
and low grazing angles. Employing the expectation-maximization
algorithm to estimate the time-varying parameters for
compound-Gaussian sea clutter, we develop a generalized
likelihood ratio test (GLRT) detector and identify a range
bin of interest. The clutter estimates are then used to
dynamically design a phase-modulated waveform that minimizes
the out-of-bin clutter contributions to this range bin. A
simulation based on parameters derived from real sea clutter
data demonstrates that our approach provides around 10 dB
improvement in detection performance over a nonadaptive
system. © 2007 IEEE.},
Doi = {10.1109/JSTSP.2007.897048},
Key = {fds235887}
}

@article{fds235888,
Author = {Lee, J-W and Chiang, M and Calderbank, AR},
Title = {Utility-optimal random-access control},
Journal = {IEEE Transactions on Wireless Communications},
Volume = {6},
Number = {7},
Pages = {2741-2750},
Year = {2007},
ISSN = {1536-1276},
url = {http://dx.doi.org/10.1109/TWC.2007.05991},
Abstract = {This paper designs medium access control (MAC) protocols for
wireless networks through the network utility maximization
(NUM) framework. A network-wide utility maximization problem
is formulated, using a collision/persistenceprobabilistic
model and aligning selfish utility with total social
welfare. By adjusting the parameters in the utility
objective functions of the NUM problem, we can also control
the tradeoff between efficiency and fairness of radio
resource allocation. We develop two distributed algorithms
to solve the utility-optimal random-access control problem,
which lead to random access protocols that have slightly
more message passing overhead than the current
exponential-backoff protocols, but significant potential for
efficiency and fairness improvement. We provide
readily-verifiable sufficient conditions under which
convergence of the proposed algorithms to a global
optimality of network utility can be guaranteed, and
numerical experiments that illustrate the value of the NUM
approach to the complexity-performance tradeoff in MAC
design. © 2007 IEEE.},
Doi = {10.1109/TWC.2007.05991},
Key = {fds235888}
}

@article{fds235889,
Author = {Lee, J-W and Tang, A and Huang, J and Chiang, M and Calderbank,
AR},
Title = {Reverse-engineering MAC: A non-cooperative game
model},
Journal = {IEEE Journal on Selected Areas in Communications},
Volume = {25},
Number = {6},
Pages = {1135-1147},
Year = {2007},
ISSN = {0733-8716},
url = {http://dx.doi.org/10.1109/JSAC.2007.070808},
Abstract = {This paper reverse-engineers backoff-based random-access MAC
protocols in ad-hoc networks. We show that the contention
resolution algorithm in such protocols is implicitly
participating in a non-cooperative game. Each link attempts
to maximize a selfish local utility function, whose exact
shape is reverse-engineered from the protocol description,
through a stochastic subgradient method in which the link
updates its persistence probability based on its
transmission success or failure. We prove that existence of
a Nash equilibrium is guaranteed in general. Then we
establish the minimum amount of backoff aggressiveness
needed, as a function of density of active users, for
uniqueness of Nash equilibrium and convergence of the best
response strategy. Convergence properties and connection
with the best response strategy are also proved for variants
of the stochastic-subgradient-based dynamics of the game.
Together with known results in reverse-engineering TCP and
BGP, this paper further advances the recent efforts in
reverse-engineering layers 2-4 protocols. In contrast to the
TCP reverse-engineering results in earlier literature, MAC
reverse-engineering highlights the non-cooperative nature of
random access. © 2007 IEEE.},
Doi = {10.1109/JSAC.2007.070808},
Key = {fds235889}
}

@article{fds235890,
Author = {Thangaraj, A and Dihidar, S and Calderbank, AR and McLaughlin, SW and Merolla, J-M},
Title = {Applications of LDPC codes to the wiretap
channel},
Journal = {IEEE Transactions on Information Theory},
Volume = {53},
Number = {8},
Pages = {2933-2945},
Year = {2007},
ISSN = {0018-9448},
url = {http://dx.doi.org/10.1109/TIT.2007.901143},
Abstract = {With the advent of quantum key distribution (QKD) systems,
perfect (i.e., information-theoretic) security can now be
achieved for distribution of a cryptographic key. QKD
systems and similar protocols use classical error-correcting
codes for both error correction (for the honest parties to
correct errors) and privacy amplification (to make an
eavesdropper fully ignorant). From a coding perspective, a
good model that corresponds to such a setting is the wire
tap channel introduced by Wyner in 1975. In this
correspondence, we study fundamental limits and coding
methods for wire tap channels. We provide an alternative
view of the proof for secrecy capacity of wire tap channels
and show how capacity achieving codes can be used to achieve
the secrecy capacity for any wiretap channel. We also
consider binary erasure channel and binary symmetric channel
special cases for the wiretap channel and propose specific
practical codes. In some cases our designs achieve the
secrecy capacity and in others the codes provide security at
rates below secrecy capacity. For the special case of a
noiseless main channel and binary erasure channel, we
consider encoder and decoder design for codes achieving
secrecy on the wiretap channel; we show that it is possible
to construct linear-time decodable secrecy codes based on
low-density parity-check (LDPC) codes that achieve secrecy.
Doi = {10.1109/TIT.2007.901143},
Key = {fds235890}
}

@article{fds235743,
Author = {Biglieri, E and Calderbank, R and Constantinides, A and Goldsmith, A and Paulraj, A and Poor, HV},
Title = {MIMO wireless communications},
Journal = {MIMO Wireless Communications},
Volume = {9780521873284},
Pages = {1-323},
Year = {2007},
Month = {January},
url = {http://dx.doi.org/10.1017/CBO9780511618420},
Abstract = {© Cambridge University Press 2007 and Cambridge University
Press, 2010. Multiple-input multiple-output (MIMO)
technology constitutes a breakthrough in the design of
wireless communications systems, and is already at the core
of several wireless standards. Exploiting multipath
scattering, MIMO techniques deliver significant performance
enhancements in terms of data transmission rate and
interference reduction. This book is a detailed introduction
to the analysis and design of MIMO wireless systems.
Beginning with an overview of MIMO technology, the authors
then examine the fundamental capacity limits of MIMO
systems. Transmitter design, including precoding and
space-time coding, is then treated in depth, and the book
closes with two chapters devoted to receiver design. Written
by a team of leading experts, the book blends theoretical
analysis with physical insights, and highlights a range of
key design challenges. It can be used as a textbook for
advanced courses on wireless communications, and will also
appeal to researchers and practitioners working on MIMO
wireless systems.},
Doi = {10.1017/CBO9780511618420},
Key = {fds235743}
}

@article{fds235891,
Author = {Diggavi, SN and Calderbank, AR and Dusad, S and Al-Dhahir,
N},
Title = {Diversity embedded space-time codes},
Journal = {IEEE Transactions on Information Theory},
Volume = {54},
Number = {1},
Pages = {33-50},
Year = {2008},
ISSN = {0018-9448},
url = {http://dx.doi.org/10.1109/TIT.2007.911280},
Abstract = {Rate and diversity impose a fundamental tradeoff in wireless
communication. High-rate space-time codes come at a cost of
lower reliability (diversity), and high reliability
(diversity) implies a lower rate. However, wireless networks
need to support applications with very different
quality-of-service (QoS) requirements, and it is natural to
ask what characteristics should be built into the physical
layer link in order to accommodate them. In this paper, we
design high-rate space-time codes that have a high-diversity
code embedded within them. This allows a form of
communication where the high-rate code opportunistically
takes advantage of good channel realizations while the
embedded high-diversity code provides guarantees that at
least part of the information is received reliably.We
provide constructions of linear and nonlinear codes for a
fixed transmit alphabet constraint. The nonlinear
constructions are a natural generalization to wireless
channels of multilevel codes developed for the additive
white Gaussian noise (AWGN) channel that are matched to
binary partitions of quadrature amplitude modulation (QAM)
and phase-shift keying (PSK) constellations. The importance
of set-partitioning to code design for the wireless channel
is that it provides a mechanism for translating constraints
in the binary domain into lower bounds on diversity
protection in the complex domain. We investigate the systems
implications of embedded diversity codes by examining value
to unequal error protection, rate opportunism, and packet
delay optimization. These applications demonstrate that
diversity-embedded codes have the potential to outperform
traditional single-layer codes in moderate signal-to-noise
(SNR) regimes. © 2008 IEEE.},
Doi = {10.1109/TIT.2007.911280},
Key = {fds235891}
}

@article{fds235892,
Author = {Pezeshki, A and Calderbank, AR and Moran, W and Howard,
SD},
Title = {Doppler resilient Golay complementary waveforms},
Journal = {IEEE Transactions on Information Theory},
Volume = {54},
Number = {9},
Pages = {4254-4266},
Year = {2008},
ISSN = {0018-9448},
url = {http://dx.doi.org/10.1109/TIT.2008.928292},
Abstract = {We describe a method of constructing a sequence (pulse
train) of phase-coded waveforms, for which the ambiguity
function is free of range sidelobes along modest Doppler
shifts. The constituent waveforms are Golay complementary
waveforms which have ideal ambiguity along the zero Doppler
axis but are sensitive to nonzero Doppler shifts. We extend
this construction to multiple dimensions, in particular to
radar polarimetry, where the two dimensions are realized by
orthogonal polarizations. Here we determine a sequence of
two-by-two Alamouti matrices where the entries involve Golay
pairs and for which the range sidelobes associated with a
matrix-valued ambiguity function vanish at modest Doppler
shifts. The Prouhet-Thue-Morse sequence plays a key role in
the construction of Doppler resilient sequences of Golay
complementary waveforms. © 2008 IEEE.},
Doi = {10.1109/TIT.2008.928292},
Key = {fds235892}
}

@article{fds235893,
Author = {Li, Y and Li, Z and Chiang, M and Calderbank, AR},
Title = {Video transmission scheduling for Peer-to-Peer live
streaming systems},
Journal = {2008 IEEE International Conference on Multimedia and Expo,
ICME 2008 - Proceedings},
Pages = {653-656},
Year = {2008},
url = {http://dx.doi.org/10.1109/ICME.2008.4607519},
Abstract = {For Internet based video broadcasting applications such as
IPTV, the Peer-to-Peer (P2P) streaming scheme has been found
to be an effective solution. An important issue in live
broadcasting is to avoid playback buffer underflow. How to
utilize the playback buffer and upload bandwidth of peers to
minimize the freeze-ups in playback, is the problem we try
to solve. In this work, we propose a successive
water-filling (SWaF) algorithm for the video transmission
scheduling in P2P live streaming system, to minimize the
playback freeze-ups among peers. SWaF algorithm only needs
each peer to optimally transmit (within its uploading
bandwidth) part of its available video segments in the
buffer to other peers requiring the content and pass small
amount message to some other peers. Moreover, SWaF has low
complexity and provable optimality. Numerical results
demonstrated the effectiveness of the proposed algorithm. ©
2008 IEEE.},
Doi = {10.1109/ICME.2008.4607519},
Key = {fds235893}
}

@article{fds235894,
Author = {Sirianunpiboon, S and Calderbank, AR and Howard,
SD},
Title = {Bayesian analysis of interference cancellation for Alamouti
multiplexing},
Journal = {IEEE Transactions on Information Theory},
Volume = {54},
Number = {10},
Pages = {4755-4761},
Year = {2008},
ISSN = {0018-9448},
url = {http://dx.doi.org/10.1109/TIT.2008.929012},
Abstract = {Space-time codes built out of Alamouti components have been
adopted in wireless standards such as UMTS, IEEE 802.11n,
and IEEE 802.16, where they facilitate higher data rates
through multiplexing of parallel data streams and the
addition of two or more antennas at the receiver that
perform interference cancellation. This correspondence
provides new theoretical insight into different algorithms
for interference cancellation through a Bayesian analysis
that expresses performance as a function of signal-to-noise
ratio (SNR) in terms of the "angles" between different
space-time coded data streams. © 2008 IEEE.},
Doi = {10.1109/TIT.2008.929012},
Key = {fds235894}
}

@article{fds235895,
Author = {Dusad, S and Diggavi, SN and Calderbank, AR},
Title = {Embedded rank distance codes for ISI channels},
Journal = {IEEE Transactions on Information Theory},
Volume = {54},
Number = {11},
Pages = {4866-4886},
Year = {2008},
ISSN = {0018-9448},
url = {http://dx.doi.org/10.1109/TIT.2008.929960},
Abstract = {Designs for transmit alphabet constrained space-time codes
naturally lead to questions about the design of rank
distance codes. Recently, diversity embedded multilevel
space-time codes for flat-fading channels have been designed
from sets of binary matrices with rank distance guarantees
over the binary field by mapping them onto quadrature
amplitude modulation (QAM) and phase-shift keying (PSK)
constellations. In this paper, we demonstrate that diversity
embedded space-time codes for fading intersymbol
interference (ISI) channels can be designed with provable
rank distance guarantees. As a corollary, we obtain an
asymptotic characterization of the fixed transmit alphabet
rate-diversity tradeoff for multiple antenna fading ISI
channels. The key idea is to construct and analyze
properties of binary matrices with a particular structure
(Toeplitz structure) induced by ISI channels. © 2008
IEEE.},
Doi = {10.1109/TIT.2008.929960},
Key = {fds235895}
}

@article{fds235896,
Author = {Bennatan, A and Calderbank, AR and Shamai, S},
Title = {Bounds on the MMSE of "bad" LDPC codes at rates above
capacity},
Journal = {46th Annual Allerton Conference on Communication, Control,
and Computing},
Pages = {1065-1072},
Year = {2008},
url = {http://dx.doi.org/10.1109/ALLERTON.2008.4797677},
Abstract = {We present bounds on the minimum mean square error (MMSE) of
LDPC codes at rates above capacity. One potential
application for MMSE estimation involves cooperative
communication. A relay following a compress-and-forward (CF)
strategy could first compute an estimate of the transmitted
codeword, to reduce the level of noise in the retransmitted
signal. Our first bound is based on an analysis of the LDPC
belief-propagation decoder. A second bound relies on the
relationship between the mutual information and the MMSE,
which was discovered by Guo et al.. We compute our bounds
for "bad" LDPC codes (requiring SNRs that are far above the
Shannon limit, for reliable communications to be possible)
and show that such codes substantially outperform "good"
codes. This advantage of "bad" codes implies an interesting
degree of freedom in the design of codes for cooperative
communications. © 2008 IEEE.},
Doi = {10.1109/ALLERTON.2008.4797677},
Key = {fds235896}
}

@article{fds235897,
Author = {Chandrashekhar, TPS and Bennatan, A and Zhang, J and Calderbank, R and Cochran, D},
Title = {Rate-achievability strategies for two-hop interference
flows},
Journal = {46th Annual Allerton Conference on Communication, Control,
and Computing},
Pages = {1432-1439},
Year = {2008},
url = {http://dx.doi.org/10.1109/ALLERTON.2008.4797731},
Abstract = {We consider a basic model for two-hop transmissions of two
information flows which interfere with each other. In this
model, two sources simultaneously transmit to two relays (in
the first hop), which then simultaneously transmit to two
destinations (in the second hop). While the transmission
during the first hop is essentially the transmission over a
classical interference channel, the transmission in the
second hop enjoys an interesting advantage. Specifically, as
a by-product of the Han-Kobayashi transmission scheme
applied to the first hop, each of the relays (in the second
hop) has access to some of the data that is intended to the
other destination, in addition to its own data. As recently
observed by Simeone et al., this opens the door to
cooperation between the relays. In this paper, we observe
that the cooperation can take the form of distributed MIMO
broadcast, thus greatly enhancing its effectiveness at high
SNR. However, since each relay is only aware of part of the
data beyond its own, full cooperation is not possible. We
propose several approaches that combine MIMO broadcast
strategies (including "dirty paper") with standard
non-cooperative strategies for the interference channel.
Numerical results are provided, which indicate that our
approaches provide substantial benefits at high SNR. © 2008
IEEE.},
Doi = {10.1109/ALLERTON.2008.4797731},
Key = {fds235897}
}

@article{fds235898,
Author = {Zoltowski, MD and Qureshi, TR and Calderbank, R},
Title = {Complementary codes based channel estimation for MIMO-OFDM
systems},
Journal = {46th Annual Allerton Conference on Communication, Control,
and Computing},
Pages = {133-138},
Year = {2008},
url = {http://dx.doi.org/10.1109/ALLERTON.2008.4797546},
Abstract = {We present a pilot-assisted method for estimating the
frequency selective channel in a MIMO-OFDM (Multiple Input
Multiple Output - Orthogonal Frequency Division
Multiplexing) system. The pilot sequence is designed using
the DFT (Discrete Fourier Transform) of the Golay
complementary sequences. Novel exploitation of the perfect
autocorrelation property of the Golay codes, in conjunction
with OSTBC (Orthogonal Space-Time Block Code) based pilot
waveform scheduling across multiple OFDM frames, facilitates
simple separation of the channel mixtures at the receive
antennas. The DFT length used to transform the complementary
sequence into the frequency domain is shown to be a key
critical parameter for correctly estimating the channel.
NMSE (Normalized Mean Squared Error) between the actual and
the estimated channel is used to characterize the estimation
performance. © 2008 IEEE.},
Doi = {10.1109/ALLERTON.2008.4797546},
Key = {fds235898}
}

@article{fds235899,
Author = {Dusad, S and Diggavi, SN and Al-Dhahir, N and Calderbank,
AR},
Title = {Diversity embedded codes: Theory and practice},
Journal = {IEEE Journal of Selected Topics in Signal
Processing},
Volume = {2},
Number = {2},
Pages = {202-219},
Year = {2008},
ISSN = {1932-4553},
url = {http://dx.doi.org/10.1109/JSTSP.2008.923817},
Abstract = {Diversity embedded codes are high-rate space-time codes that
have a high-diversity code embedded within them. They allow
a form of communication where the high-rate code
opportunistically takes advantage of good channel
realizations while the embedded high-diversity code provides
guarantees that at least part of the information is received
reliably. Over the past few years, code designs and
fundamental limits of performance for such codes have been
developed. In this paper, we review these ideas by giving
the developments in a unified framework. In particular, we
present both the coding technique as well as
information-theoretic bounds in the context of Intersymbol
Interference (ISI) channels. We investigate the systems
implications of diversity embedded codes by examining value
to network utility maximization, unequal error protection
for wireless transmission, rate opportunism and packet delay
optimization. © 2008 IEEE.},
Doi = {10.1109/JSTSP.2008.923817},
Key = {fds235899}
}

@article{fds235900,
Author = {Li, Y and Li, Z and Chiang, M and Calderbank, AR},
Title = {Content-aware distortion-fair video streaming in
networks},
Journal = {GLOBECOM - IEEE Global Telecommunications
Conference},
Pages = {1768-1773},
Year = {2008},
url = {http://dx.doi.org/10.1109/GLOCOM.2008.ECP.342},
Abstract = {Internet is experiencing an explosive growth of video
traffic. Given the limited network bandwidth resources, how
to provide Internet users with good video playback quality
is a key problem. For video clips competing bandwidth, we
propose an approach of Content-Aware distortion-Fair (CAF)
video delivery scheme, which is assumed to be aware of the
characteristics of video frames and ensures max-min
distortion fair sharing among video flows. Different from
bandwidth fair sharing, CAF targets video playback quality
fairness for the reason that users care about video quality
rather than bandwidth. The proposed CAF approach does not
need an analytical rate-distortion function which is
difficult to estimate, but instead, it uses the explicit
distortion of every frame which is induced by frame drop.
Our CAF approach is fast and practical with content-aware
cooperation. Experimental results show that the proposed
approach yields better quality of service when the network
is congested compared with the approach not rate-distortion
optimized, and it makes competing video clips help each
other to get fair playback quality. © 2008
IEEE.},
Doi = {10.1109/GLOCOM.2008.ECP.342},
Key = {fds235900}
}

@article{fds235901,
Author = {Lee, J-W and Chiang, M and Calderbank, AR},
Title = {On the achievable efficiency-fairness tradeoff in
utility-optimal MAC protocols},
Journal = {IEICE Transactions on Communications},
Volume = {E91-B},
Number = {4},
Pages = {1231-1234},
Year = {2008},
ISSN = {0916-8516},
url = {http://dx.doi.org/10.1093/ietcom/e91-b.4.1231},
Abstract = {We use the network utility maximization (NUM) framework to
create an efficient and fair medium access control (MAC)
protocol for wireless networks. By adjusting the parameters
in the utility objective functions of NUM problems, we
control the tradeoff between efficiency and fairness of
radio resource allocation through a rigorous and systematic
design. In this paper, we propose a scheduling-based MAC
protocol. Since it provides an upper-bound on the achievable
performance, it establishes the optimality benchmarks for
comparison with other algorithms in related work. Copyright
© 2008 The Institute of Electronics, Information and
Communication Engineers.},
Doi = {10.1093/ietcom/e91-b.4.1231},
Key = {fds235901}
}

@article{fds235902,
Author = {Li, Y and Tian, C and Diggavi, S and Chiang, M and Calderbank,
AR},
Title = {Network resource allocation for competing multiple
description transmissions},
Journal = {GLOBECOM - IEEE Global Telecommunications
Conference},
Pages = {2366-2371},
Year = {2008},
url = {http://dx.doi.org/10.1109/GLOCOM.2008.ECP.455},
Abstract = {To provide real-time multimedia services over a network is
challenging due to the stringent delay requirements in the
presence of complex network dynamics. Yet such services are
beginning to be deployed over best effort networks. Multiple
description (MD) coding is one approach to transmit the
media over diverse (multiple) paths to reduce the
detrimental effects caused by path failures or delay. The
novelty of this work is to investigate the resource
allocation in a network, where there are several competing
MD coded streams. This is done by considering a framework
that chooses the operating points for asymmetric MD coding
to maximize total quality of the users, while these streams
are sent over multiple routing paths. We study the joint
optimization of multimedia (source) coding and congestion
control in wired networks. These ideas are extended to joint
source coding and channel coding in wireless networks. In
both situations, we propose distributed algorithms for
optimal resource allocation. In the presence of path loss
and competing users, the service quality to any particular
MD stream could be uncertain. In such circumstances it might
be tempting to expect that greater redundancy in the MD
streams is needed to protect against such failures. However,
one surprising aspect of our study reveals that for large
number of users competing for the same resources, the
overall system could benefit through opportunistic
(hierarchical) strategies. In general networks, our studies
indicate that the user composition varies from conservative
to opportunistic operating points, depending on the number
of users and their network vantage points. © 2008
IEEE.},
Doi = {10.1109/GLOCOM.2008.ECP.455},
Key = {fds235902}
}

@article{fds235903,
Author = {Sirianunpiboon, S and Calderbank, AR and Howard,
SD},
Title = {Cognitive decoding and the Golden code},
Journal = {European Signal Processing Conference},
Year = {2008},
ISSN = {2219-5491},
Abstract = {Space time signal processing starts with a system of linear
equations where signals are multiplied by channel gains, and
the standard criteria for the design of space time codes
focus on differences between codewords at the transmitter.
The value of algebraic constructions is to transfer
structure (correlation) at the transmitter to structure at
the receiver, and the focus of this paper is the induced
channel at the receiver. We use the Golden code to explore
the idea of introducing structure at the transmitter to
enable low complexity decoding at the receiver. This is an
important special case, since the Golden code is
incorporated in the IEEE 802.16 standard, but the value of
our approach is not limited to this example. We describe a
cognitive decoder for the Golden code with complexity O(N 2)
that comes within 3dB of full MAP/ML decoding. The decoder
is cognitive in that it uses channel state information to
choose between two algorithms in a way that is independent
of the signal-to-noise ratio. The primary algorithm is
interference cancellation which fails to perform well on a
proportion of channels. We identify the channel conditions
for which inteference cancellation fails and show that for
these channels the decoding problem effectively reduces to a
single receive antenna decoding problem for which we have
developed an efficient zero forcing algorithm. Previous
hybrid approaches based on sphere decoding have cubic worst
case complexity and employ decision rules based on condition
number of the posterior covariance matrix. Interference
cancellation is different in that orientation of the
covariance matters. The cognitive decoder for the Golden
code provides a uniform solution to different wireless
environments (Rayleigh/Rician) that combine rich scattering
and line of sight components. The gap between cognitive and
full MAP/ML decoding reduces to essentially ML performance
as the line of sight component becomes more dominant.
Key = {fds235903}
}

@article{fds235904,
Author = {Zoltowski, MD and Qureshi, TR and Calderbank, R and Moran,
W},
Title = {Unitary design of radar waveform diversity
sets},
Journal = {Conference Record of the Asilomar Conference on Signals,
Systems and Computers},
Pages = {26-30},
Year = {2008},
ISSN = {1058-6393},
url = {http://dx.doi.org/10.1109/ACSSC.2008.5074353},
Abstract = {In this work, multiple radar waveforms are simultaneously
transmitted, emitted from different "virtual" antennas. The
goal is to process the returns in such a way that the
overall ambiguity function is a sum of ambiguity functions
better approximating the desired thumbtack shape. A 4×4
example involves two spatially separated antennas with each
able to transmit and receive simultaneously on two different
polarizations. The 4×4 unitary design dictates the
scheduling of the waveforms over the four virtual antennas
over four PRIs (Pulse Repetition Intervals), and how the
matched filtering of the returns over four PRIs is combined
in to achieve both perfect separation (of the superimposed
returns) and perfect reconstruction. Perfect reconstruction
means the sum of the time-autocorrelations associated with
each of the four waveforms is a delta function. Conditions
for both perfect separation and perfect reconstruction are
developed, and a variety of waveform sets satisfying both
are presented. © 2008 IEEE.},
Doi = {10.1109/ACSSC.2008.5074353},
Key = {fds235904}
}

@article{fds235905,
Author = {Liu, J and Calderbank, AR},
Title = {The Icosian code and the E8 lattice: A new 4 × 4
space-time code with nonvanishing determinant},
Journal = {IEEE Transactions on Information Theory},
Volume = {54},
Number = {8},
Pages = {3782-3789},
Year = {2008},
ISSN = {0018-9448},
url = {http://dx.doi.org/10.1109/TIT.2008.926352},
Abstract = {This paper introduces a new rate-2, full-diversity
space-time code for four transmit antennas and one receive
antenna. The 4 × 4 codeword matrix consists of four 2 × 2
Alamouti blocks with entries from Q(i,√5), and these
blocks can be viewed as quaternions which in turn represent
rotations in R3. The Alamouti blocks that appear in a
codeword are drawn from the icosian ring consisting of all
linear combinations of 120 basic rotations corresponding to
symmetries of the icosahedron. This algebraic structure is
different from the Golden code, but the complex entries are
taken from a common underlying field. The minimum
determinant is bounded below by a constant that is
independent of the signal constellation, and the new code
admits a simple decoding scheme that makes use of a
geometric correspondence between the icosian ring and the E8
lattice. © 2008 IEEE.},
Doi = {10.1109/TIT.2008.926352},
Key = {fds235905}
}

@article{fds235906,
Author = {Aggarwal, V and Calderbank, AR},
Title = {Boolean functions, projection operators, and quantum error
correcting codes},
Journal = {IEEE Transactions on Information Theory},
Volume = {54},
Number = {4},
Pages = {1700-1707},
Year = {2008},
ISSN = {0018-9448},
url = {http://dx.doi.org/10.1109/TIT.2008.917720},
Abstract = {This paper describes a fundamental correspondence between
Boolean functions and projection operators in Hilbert space.
The correspondence is widely applicable, and it is used in
this paper to provide a common mathematical framework for
the design of both additive and nonadditive quantum error
correcting codes. The new framework leads to the
construction of a variety of codes including an infinite
class of codes that extend the original ((5, 6, 2)) code
found by Rains et al It also extends to operator quantum
error correcting codes. © 2008 IEEE.},
Doi = {10.1109/TIT.2008.917720},
Key = {fds235906}
}

@article{fds236070,
Author = {Pezeshki, A and Kutyniok, G and Calderbank, R},
Title = {Fusion frames and robust dimension reduction},
Journal = {CISS 2008, The 42nd Annual Conference on Information
Sciences and Systems},
Pages = {264-268},
Year = {2008},
url = {http://dx.doi.org/10.1109/CISS.2008.4558533},
Abstract = {We consider the linear minimum meansquared error (LMMSE)
estimation of a random vector of interest from its fusion
frame measurements in presence noise and subspace erasures.
Each fusion frame measurement is a low-dimensional vector
whose elements are inner products of an orthogonal basis for
a fusion frame subspace and the random vector of interest.
We derive bounds on the mean-squared error (MSE) and show
that the MSE will achieve its lower bound if the fusion
frame is tight. We prove that tight fusion frames consisting
of equidimensional subspaces have maximum robustness with
respect to erasures of one subspace, and that the optimal
dimension depends on SNR. We also show that tight fusion
frames consisting of equi-dimensional subspaces with equal
pairwise chordal distances are most robust with respect to
two and more subspace erasures, and refer to such fusion
frames as equi-distance tight fusion frames. Finally, we
show that the squared chordal distance between the subspaces
in such fusion frames meets the so-called simplex bound, and
thereby establish a connection between equidistance tight
fusion frames and optimal Grassmannian packings. © 2008
IEEE.},
Doi = {10.1109/CISS.2008.4558533},
Key = {fds236070}
}

@article{fds236071,
Author = {Calderbank, R and Dickinson, B},
Title = {CISS 2008, The 42nd Annual Conference on Information
Sciences and Systems: Welcome},
Journal = {CISS 2008, The 42nd Annual Conference on Information
Sciences and Systems},
Pages = {i-ii},
Year = {2008},
url = {http://dx.doi.org/10.1109/CISS.2008.4558477},
Doi = {10.1109/CISS.2008.4558477},
Key = {fds236071}
}

@article{fds236072,
Author = {Suvorova, S and Moron, B and Howard, S and Calderbank,
R},
Title = {Application of Doppler resilient complementary waveforms to
target tracking},
Journal = {IEEE International Conference on Acoustics Speech and Signal
Processing},
Pages = {1497-1500},
Year = {2008},
ISSN = {1520-6149},
url = {http://dx.doi.org/10.1109/ICASSP.2008.4517905},
Abstract = {The use of complementary codes as a means of reducing radar
range sidelobes is well-known, but lack of resilience to
Doppler is often cited as a reason not to deploy them. This
work describes techniques for providing Doppler resilience
with an emphasis on tailoring Doppler performance to the
specific aim of target tracking. The Doppler performance can
be varied by suitably changing the order of transmission of
multiple sets of complementary waveforms. We have developed
a method that improves Doppler performance significantly by
arranging the transmission of multiple copies of
complementary waveforms according to the first order
Reed-Müller codes. Here we demonstrate significant tracking
gains in the context of accelerating targets by the use of
adaptively chosen waveform sequences of this kind, compared
to both a fixed sequence of similar waveforms, and an LFM
Doi = {10.1109/ICASSP.2008.4517905},
Key = {fds236072}
}

@article{fds236073,
Author = {Howard, SD and Calderbank, AR and Searle, SJ},
Title = {A fast reconstruction algorithm for deterministic
compressive sensing using second order reed-muller
codes},
Journal = {CISS 2008, The 42nd Annual Conference on Information
Sciences and Systems},
Pages = {11-15},
Year = {2008},
url = {http://dx.doi.org/10.1109/CISS.2008.4558486},
Abstract = {This paper proposes a deterministic compressed sensing
matrix that comes by design with a very fast reconstruction
algorithm, in the sense that its complexity depends only on
the number of measurements n and not on the signal dimension
N. The matrix construction is based on the second order
Reed-Muller codes and associated functions. This matrix does
not have RIP uniformly with respect to all k-sparse vectors,
but it acts as a near isometry on k-sparse vectors with very
high probability. © 2008 IEEE.},
Doi = {10.1109/CISS.2008.4558486},
Key = {fds236073}
}

@article{fds236074,
Author = {Wu, Y and Calderbank, R},
Title = {Code diversity in multiple antenna wireless
communication},
Journal = {IEEE International Symposium on Information Theory -
Proceedings},
Pages = {1078-1082},
Year = {2008},
url = {http://dx.doi.org/10.1109/ISIT.2008.4595153},
Abstract = {The standard approach to the design of individual space-time
codes is based on optimizing diversity and coding gain. This
geometric approach leads to remarkable examples, such as the
Golden Code, for which the complexity of Maximum Likelihood
(ML) decoding is considerable. Code diversity is an
alternative approach where a small number of feedback bits
are used to select from a family of space-time codes.
Feedback can be combined with sub-optimal low complexity
decoding of the component codes to match ML decoding
performance of any individual code in the family. It can
also be combined with ML decoding of the component codes to
improve performance beyond ML decoding performance of any
individual code. One method of implementing code diversity
is the use of feedback to adapt the phase of a transmitted
signal. Phase adaptation with the 4 × 4 Quasi-Orthogonal
Space-Time Code (QOSTBC) is shown to be almost information
lossless; that is, this form of space-time coding does not
reduce the capacity of the underlying multiple antenna
wireless channel. Code diversity can also be used to improve
performance of multi-user detection by reducing interference
between users. Phase adaptation with two Alamouti users
makes it possible for the Zero Forcing (ZF) or decorrelating
detector to match the performance of ML joint detection. ©
2008 IEEE.},
Doi = {10.1109/ISIT.2008.4595153},
Key = {fds236074}
}

@article{fds236075,
Author = {Chui, J and Calderbank, AR},
Title = {Multilevel diversity-embedded space-time codes for video
Journal = {IEEE International Symposium on Information Theory -
Proceedings},
Pages = {1068-1072},
Year = {2008},
url = {http://dx.doi.org/10.1109/ISIT.2008.4595151},
Abstract = {Advances in wireless technologies, such as WiMAX [1], allow
high data rates and high reliability through the use of
MIMO-OFDM. However, they are not optimally designed for
broadcasting. The nature of the wireless medium may cause an
entire frame to be in outage with little chance of recovery.
One strategy to overcome this deficit is to employ diversity
embedding, which protect different bits with different
diversity orders. Such codes exhibit the property that even
if the entire frame is in outage, a subset of the frame may
still be reliably recovered. In this paper, we present
space-time codes designed for MIMO-OFDM systems which
achieve diversity embedding. We demonstrate how these codes
can increase PSNR for video broadcasting in WiMAX © 2008
IEEE.},
Doi = {10.1109/ISIT.2008.4595151},
Key = {fds236075}
}

@article{fds236076,
Author = {Jafarpour, S and Pezeshki, A and Calderbank, R},
Title = {Experiments with compressively sampled images and a new
debluring-denoising algorithm},
Journal = {Proceedings - 10th IEEE International Symposium on
Multimedia, ISM 2008},
Pages = {66-73},
Year = {2008},
url = {http://dx.doi.org/10.1109/ISM.2008.119},
Abstract = {In this paper we will examine the effect of different
parameters in the quality of real compressively sampled
images in the compressed sensing framework. We will select a
variety of different real images of different types and test
the quality of the recovered images, the recovery time, and
required resources when different measurement methods with
different parameters are used or when different recovering
methods are applied. Then we will propose an algorithm to
reduce the noise in the recovered images and sharpen them
simultaneously. The algorithm exploits a well-known
bilateral filtering in order to increase the confidence in
margins and edges, and then uses an adaptive unsharp mask
method to sharpen the images. The adaptive unsharp mask
method extends the ordinary unsharp mask method and uses
machine learning square loss minimization and regression in
order to learn the optimal unsharping parameters. We will
argue why both bilateral filtering and unsharp mask methods
should be used in the algorithm simultaneously. Finally, we
will show the results of applying the algorithm on real
images that are recovered using the compressed sensing
method and we will interpret the experimental results. ©
2008 IEEE.},
Doi = {10.1109/ISM.2008.119},
Key = {fds236076}
}

@article{fds235907,
Author = {Papandreou-Suppappola, A and Nehorai, A and Calderbank,
R},
Title = {Waveform-agile sensing and processing},
Journal = {IEEE Signal Processing Magazine},
Volume = {26},
Number = {1},
Pages = {10-11},
Year = {2009},
ISSN = {1053-5888},
url = {http://dx.doi.org/10.1109/MSP.2008.930413},
Abstract = {The six articles in this special issue focus on
waveform-agile sensing and processing. © 2009
IEEE.},
Doi = {10.1109/MSP.2008.930413},
Key = {fds235907}
}

@article{fds235908,
Author = {Kutyniok, G and Pezeshki, A and Calderbank, R and Liu,
T},
Title = {Robust dimension reduction, fusion frames, and Grassmannian
packings},
Journal = {Applied and Computational Harmonic Analysis},
Volume = {26},
Number = {1},
Pages = {64-76},
Year = {2009},
ISSN = {1063-5203},
url = {http://dx.doi.org/10.1016/j.acha.2008.03.001},
Abstract = {We consider estimating a random vector from its measurements
in a fusion frame, in presence of noise and subspace
erasures. A fusion frame is a collection of subspaces, for
which the sum of the projection operators onto the subspaces
is bounded below and above by constant multiples of the
identity operator. We first consider the linear minimum
mean-squared error (LMMSE) estimation of the random vector
of interest from its fusion frame measurements in the
presence of additive white noise. Each fusion frame
measurement is a vector whose elements are inner products of
an orthogonal basis for a fusion frame subspace and the
random vector of interest. We derive bounds on the
mean-squared error (MSE) and show that the MSE will achieve
its lower bound if the fusion frame is tight. We then
analyze the robustness of the constructed LMMSE estimator to
erasures of the fusion frame subspaces. We limit our erasure
analysis to the class of tight fusion frames and assume that
all erasures are equally important. Under these assumptions,
we prove that tight fusion frames consisting of
equi-dimensional subspaces have maximum robustness (in the
MSE sense) with respect to erasures of one subspace among
all tight fusion frames, and that the optimal subspace
dimension depends on signal-to-noise ratio (SNR). We also
prove that tight fusion frames consisting of
equi-dimensional subspaces with equal pairwise chordal
distances are most robust with respect to two and more
subspace erasures, among the class of equi-dimensional tight
fusion frames. We call such fusion frames equi-distance
tight fusion frames. We prove that the squared chordal
distance between the subspaces in such fusion frames meets
the so-called simplex bound, and thereby establish
connections between equi-distance tight fusion frames and
optimal Grassmannian packings. Finally, we present several
examples for the construction of equi-distance tight fusion
frames. © 2008 Elsevier Inc. All rights
reserved.},
Doi = {10.1016/j.acha.2008.03.001},
Key = {fds235908}
}

@article{fds235909,
Author = {Calderbank, R and Howard, SD and Moran, B},
Title = {Waveform diversity in radar signal processing: A focus on
the use and control of degrees of freedom},
Journal = {IEEE Signal Processing Magazine},
Volume = {26},
Number = {1},
Pages = {32-41},
Year = {2009},
ISSN = {1053-5888},
url = {http://dx.doi.org/10.1109/MSP.2008.930414},
Abstract = {Complementary waveforms developed by Golay are conceived to
improve the sensitivity of far infrared spectrometry, which
is similar to those developed by Tseng and Liu to analyze
acoustic surface wave phenomena. In such a matrix, phase
coded waveforms indexed by array element and by the
pulse-repetition intervals are the basis of radar
illumination. Their polarization of constituent waveforms
also may vary. This thus make it possible to segregate and
calibrate methods of controlling individual degrees of
freedom before examining them in combination.},
Doi = {10.1109/MSP.2008.930414},
Key = {fds235909}
}

@article{fds235910,
Author = {Li, Z and Li, Y and Chiang, M and Calderbank, R and Chen,
YC},
Title = {Optimal transmission scheduling for scalable wireless video
broadcast with rateless erasure correction
code},
Journal = {2009 6th IEEE Consumer Communications and Networking
Conference, CCNC 2009},
Year = {2009},
url = {http://dx.doi.org/10.1109/CCNC.2009.4784712},
Abstract = {With the advances in wireless technology and explosive
growth of mobile devices and wireless networks, mobile TV is
becoming a popular application. The main technical challenge
to wireless video broadcast is to provide the best quality
of service possible under the radio resource constraints. In
this paper we propose an application layer middleware
solution that utilizes the scalability in video coding with
rateless erasure correction codes to achieve a balance in
the quality of service (QoS) and radio resource efficiency.
Simulation results demonstrate the effectiveness of the
Doi = {10.1109/CCNC.2009.4784712},
Key = {fds235910}
}

@article{fds235911,
Author = {Li, Y and Li, Z and Chiang, M and Calderbank, AR},
Title = {Energy-efficient video transmission scheduling for wireless
peer-to-peer live streaming},
Journal = {2009 6th IEEE Consumer Communications and Networking
Conference, CCNC 2009},
Year = {2009},
url = {http://dx.doi.org/10.1109/CCNC.2009.4784766},
Abstract = {The Peer-to-Peer (P2P) streaming has shown as an effective
solution for wireline video applications, while for the
wireless video streaming applications, the limited radio
resource and battery energy are the main constraints on the
way of P2P applications. An important issue in live video
streaming quality of service is to avoid playback buffer
underflow, and a challenge from wireless applications is the
desire of energy efficiency. The problem we try to solve is
how to utilize P2P schemes in video streaming and schedule
the video transmission among peers to minimize the "freeze-
ups" in playback caused by buffer underflow. In this work,
we propose energy-efficient algorithm for the video
transmission scheduling in wireless P2P live streaming
system, to minimize the playback freeze-ups among peers.
Further the algorithm is extended to two scenarios: peers'
reluctance of consuming battery energy and allowing
overhearing, with alternative energy-efficient algorithms
proposed for the second scenario. Numerical results show the
effectiveness of the proposed algorithms. The results also
demonstrate that peers' selfishness may reduce the energy
efficiency, but allowing overhearing could increase energy
Doi = {10.1109/CCNC.2009.4784766},
Key = {fds235911}
}

@article{fds235912,
Author = {Qureshi, T and Zoltowski, M and Calderbank, R},
Title = {MIMO-OFDM channel estimation using golay complementary
sequences},
Journal = {2009 International Waveform Diversity and Design Conference
Proceedings, WDD 2009},
Pages = {253-257},
Year = {2009},
url = {http://dx.doi.org/10.1109/WDDC.2009.4800355},
Abstract = {We present a pilot-assisted method for estimating the
frequency selective channel in a MIMO-OFDM (Multiple Input
Multiple Output - Orthogonal Frequency Division
Multiplexing) system. The pilot sequence is designed using
the DFT (Discrete Fourier Transform) of the Golay
complementary sequences. Novel exploitation of the perfect
autocorrelation property of Golay complementary sequences,
in conjunction with OSTBC (Orthogonal Space Time Block Code)
based pilot waveform scheduling across multiple OFDM frames,
facilitates simple separation of the channel mixtures at the
receive antennas. The DFT length used to transform the
complementary sequence into the frequency domain is shown to
be a key critical parameter for correctly estimating the
channel. This channel estimation scheme is then extended to
antenna arrays of arbitrary sizes. ©2009
IEEE.},
Doi = {10.1109/WDDC.2009.4800355},
Key = {fds235912}
}

@article{fds235913,
Author = {Chi, Y and Pezeshki, A and Calderbank, R and Howard,
S},
Title = {Range sidelobe suppression in a desired Doppler
interval},
Journal = {2009 International Waveform Diversity and Design Conference
Proceedings, WDD 2009},
Pages = {258-262},
Year = {2009},
url = {http://dx.doi.org/10.1109/WDDC.2009.4800356},
Abstract = {We present a novel method of constructing a Doppler
resilient pulse train of Golay complementary waveforms, for
which the range sidelobes of the pulse train ambiguity
function vanish inside a desired Doppler interval. This is
accomplished by coordinating the transmission of a Golay
pair of phase coded waveforms in time according to the 1's
and -1's in a biphase sequence. The magnitude of the range
sidelobes of the pulse train ambiguity function is shown to
be proportional to the magnitude spectrum of the biphase
sequence. Range sidelobes inside a desired Doppler interval
are suppressed by selecting a sequence whose spectrum has a
high-order null at a Doppler frequency inside the desired
interval. We show that the spectrum of the biphase sequence
obtained by oversampling the length-2M Prouhet-Thue-Morse
(PTM) sequence by a factor m has an Mth-order null at all
rational Doppler shifts Θ0 = 2πl /m, where l ≠ 0 and
m≠ 1 are co-prime integers. This spectrum also has an (M -
1)th-order null at zero Doppler and (M - h - 1)th-order
nulls at all Doppler shifts Θ0 = 2πl /(2hm), where l ≠ 0
andm ≠ 1 are again co-prime and 1 ≤ h ≤ M - 1. ©2009
IEEE.},
Doi = {10.1109/WDDC.2009.4800356},
Key = {fds235913}
}

@article{fds235914,
Author = {Sirianunpiboon, S and Davis, LM and Calderbank,
R},
Title = {Performance of the golden code in the presence of
polarization diversity},
Journal = {Proceedings of the 2009 Australian Communications Theory
Workshop, AusCTW 2009},
Pages = {23-27},
Year = {2009},
url = {http://dx.doi.org/10.1109/AUSCTW.2009.4805594},
Abstract = {The performance of a multiple-input multipleoutput (MIMO)
system depends strongly on the scattering environment and
antenna spacing. The use of dual-polarized antennas is a
promising alternative both in terms of diversity and
effective use of space. In this paper we investigate the
performance of the Golden code with polarization diversity;
where the two spatially separated antennas are replaced by a
single dual polarised antenna. We analyse the performance of
the Golden code in terms of an angle between the channels
corresponding to the two receivers, which allows us to
predict performance without necessarily needing to resort to
simulations. Analysis and simulation results show that with
the introduction of polarization diversity the performance
of the Golden code can be made consistently good across both
rich scattering and line of sight (LOS) conditions. © 2009
IEEE.},
Doi = {10.1109/AUSCTW.2009.4805594},
Key = {fds235914}
}

@article{fds235915,
Author = {Li, Y and Chiang, M and Calderbank, AR and Diggavi,
SN},
Title = {Optimal rate-reliability-delay tradeoff in networks with
Journal = {IEEE Transactions on Communications},
Volume = {57},
Number = {5},
Pages = {1390-1401},
Year = {2009},
ISSN = {0090-6778},
url = {http://dx.doi.org/10.1109/TCOMM.2009.05.070198},
Abstract = {Networks need to accommodate diverse applications with
different Quality-of-Service (QoS) requirements. New ideas
at the physical layer are being developed for this purpose,
such as diversity embedded coding, which is a technique that
combines high rates with high reliability. We address the
problem of how to fully utilize different rate-reliability
characteristics at the physical layer to support different
types of traffic over a network and to jointly maximize
their utilities. We set up a new framework based on utility
maximization for networks with composite links, meaning that
each link consists of sub-links that can attain different
rate-reliability characteristics simultaneously. We
incorporate delay, in addition to rate and reliability, into
the utility functions. To accommodate different types of
traffic, we propose distributed algorithms converging to the
optimal rate-reliability-delay tradeoff based on capacity
division and priority queueing. Numerical results show that
compared with traditional codes, the new codes can provide
higher network utilities for all traffic types
simultaneously. The results also show that priority queueing
achieves higher network utility than capacity division. ©
2009 IEEE.},
Doi = {10.1109/TCOMM.2009.05.070198},
Key = {fds235915}
}

@article{fds235916,
Author = {Aggarwal, V and Bennatan, A and Calderbank, AR},
Title = {On maximizing coverage in Gaussian relay
channels},
Journal = {IEEE Transactions on Information Theory},
Volume = {55},
Number = {6},
Pages = {2518-2536},
Year = {2009},
ISSN = {0018-9448},
url = {http://dx.doi.org/10.1109/TIT.2009.2018337},
Abstract = {Results for Gaussian relay channels typically focus on
maximizing transmission rates for given locations of the
source, relay, and destination. We introduce an alternative
perspective, where the objective is maximizing coverage for
a given rate. The new objective captures the problem of how
to deploy relays to provide a given level of service to a
particular geographic area, where the relay locations become
a design parameter that can be optimized. We evaluate the
decode-and-forward (DF) and compress-and-forward (CF)
strategies for the relay channel with respect to the new
objective of maximizing coverage. When the objective is
maximizing rate, different locations of the destination
favor different strategies. When the objective is coverage
for a given rate, and the relay is able to decode, DF is
uniformly superior in that it provides coverage at any point
served by CF. When the channel model is modified to include
random fading, we show that the monotone ordering of
coverage regions is not always maintained. While the
coverage provided by DF is sensitive to changes in the
location of the relay and the path loss exponent, CF
exhibits a more graceful degradation with respect to such
changes. The techniques used to approximate coverage regions
are new and may be of independent interest. © 2009
IEEE.},
Doi = {10.1109/TIT.2009.2018337},
Key = {fds235916}
}

@article{fds235917,
Author = {Zoltowski, MD and Qureshi, TR and Calderbank, R},
Title = {Channel estimation for MIMO-OFDM using complementary
codes},
Journal = {RWS 2009 IEEE Radio and Wireless Symposium,
Proceedings},
Pages = {159-162},
Year = {2009},
url = {http://dx.doi.org/10.1109/RWS.2009.4957309},
Abstract = {We present a pilot-assisted method for estimating the
frequency selective channel in a MIMO-OFDM (Multiple Input
Multiple Output - Orthogonal Frequency Division
Multiplexing) system. The pilot sequence is designed using
the DFT (Discrete Fourier Transform) of the Golay
complementary sequences. Novel exploitation of the perfect
autocorrelation property of the Golay codes, in conjunction
with OSTBC (Orthogonal Space-Time Block Code) based pilot
waveform scheduling across multiple OFDM frames, facilitates
simple separation of the channel mixtures at the receive
antennas. The DFT length used to transform the complementary
sequence into the frequency domain is shown to be a key
critical parameter for correctly estimating the channel.
NMSE (Normalized Mean Squared Error) between the actual and
the estimated channel is used to characterize the estimation
Doi = {10.1109/RWS.2009.4957309},
Key = {fds235917}
}

@article{fds235918,
Author = {Islam, KMZ and Rabiei, P and Al-Dhahir, N and Diggavi, SN and Calderbank, AR},
Title = {Linear diversity-embedding STBC: Design issues and
applications},
Journal = {IEEE Transactions on Communications},
Volume = {57},
Number = {6},
Pages = {1578-1583},
Year = {2009},
ISSN = {0090-6778},
url = {http://dx.doi.org/10.1109/TCOMM.2009.06.080008},
Abstract = {We design a novel class of space-time codes, called linear
diversity-embedding space-time block codes (LDE-STBC) where
a high-rate STBC is linearly superimposed on a highdiversity
STBC without requiring channel knowledge at the transmitter.
In applying this scheme to multimedia wireless
communications, each traffic type constitutes a transmission
layer that operates at a suitable rate-diversity tradeoff
point according to its quality-of-service requirements.
This, in turn, provides an unequal-error-protection (UEP)
capability to the different information traffic types and
allows a form of wireless communications where the high-rate
STBC opportunistically takes advantage of good channel
realizations while the embedded high-diversity STBC ensures
that at least part of the information is decoded reliably.
We investigate transceiver design issues specific to
LDE-STBC including reduced-complexity coherent decoding and
effective schemes to vary the coding gain to further enhance
UEP capabilities of the code. Furthermore, we investigate
the application of LDE-STBC to wireless multicasting and
demonstrate its performance advantage over conventional
equal-error-protection STBC. © 2009 IEEE.},
Doi = {10.1109/TCOMM.2009.06.080008},
Key = {fds235918}
}

@article{fds235919,
Author = {Tan, CW and Calderbank, AR},
Title = {Multiuser detection of alamouti signals},
Journal = {IEEE Transactions on Communications},
Volume = {57},
Number = {7},
Pages = {2080-2089},
Year = {2009},
ISSN = {0090-6778},
url = {http://dx.doi.org/10.1109/TCOMM.2009.07.070592},
Abstract = {In a MIMO multiple-access channel where users employ
Space-Time Block Codes (STBC), interference cancellation can
be used to suppress co-channel interference and recover the
desired signal of each user at the receiver. Leveraging the
special properties of Alamouti matrices, we first show that
spatial multiplexing of Alamouti signals retains the
space-time diversity gain of Alamouti signaling using our
proposed low-complexity Alamouti BLAST-MMSE (A-BLAST)
Algorithm. Next, in contrast to traditional transmit
diversity that focuses on STBC construction at the
transmitter, this paper looks at transmit diversity from the
perspective of the receiver. In other words, the receiver
gets to choose the STBC's, which are favourable to the
channel assuming a fixed BLAST receive algorithm. In a
multiuserMAC setting, we first present a systematic
methodology to exploit different decomposition structure in
Alamouti matrices, each with different tradeoff between
performance and decoding complexity using possibly different
MIMO receive algorithms. We then demonstrate that the notion
of angles (the inner product of two quaternionic vectors)
between multiuser channels determines the performance of
MIMO receive algorithms. As an application of the general
theory, we transform the decoding problem for several types
of Quasi-Orthogonal STBC (QOSTBC) into multiuser detection
of virtual Alamouti users. Building upon our A-BLAST
Algorithm, we propose new algorithms for decoding
single-user and multiuser QOSTBC. In particular, we show
that bit error probability is a function of the quaternionic
angle between virtual users (for a single user) or multiple
users. This angle varies with the type of QOSTBC and leads
to a new form of adaptive modulation called code diversity,
where feedback instructs the transmitter how to choose from
a plurality of codes. © 2009 IEEE.},
Doi = {10.1109/TCOMM.2009.07.070592},
Key = {fds235919}
}

@article{fds235920,
Author = {Aggarwal, V and Sankar, L and Calderbank, AR and Poor,
HV},
Title = {Secrecy capacity of a class of orthogonal relay eavesdropper
channels},
Journal = {EURASIP Journal on Wireless Communications and
Networking},
Volume = {2009},
Year = {2009},
ISSN = {1687-1472},
url = {http://dx.doi.org/10.1155/2009/494696},
Abstract = {The secrecy capacity of relay channels with orthogonal
components is studied in the presence of an additional
passive eavesdropper node. The relay and destination receive
signals from the source on two orthogonal channels such that
the destination also receives transmissions from the relay
on its channel. The eavesdropper can overhear either one or
both of the orthogonal channels. Inner and outer bounds on
the secrecy capacity are developed for both the discrete
memoryless and the Gaussian channel models. For the discrete
memoryless case, the secrecy capacity is shown to be
achieved by a partial decode-and-forward (PDF) scheme when
the eavesdropper can overhear only one of the two orthogonal
channels. Two new outer bounds are presented for the
Gaussian model using recent capacity results for a Gaussian
multiantenna point-to-point channel with a multiantenna
eavesdropper. The outer bounds are shown to be tight for two
subclasses of channels. The first subclass is one in which
the source and relay are clustered, and the eavesdropper
receives signals only on the channel from the source and the
relay to the destination, for which the PDF strategy is
optimal. The second is a subclass in which the source does
not transmit to the relay, for which a noise-forwarding
strategy is optimal. Copyright © 2009 Vaneet Aggarwal et
al.},
Doi = {10.1155/2009/494696},
Key = {fds235920}
}

@article{fds235921,
Author = {Jafarpour, S and Xu, W and Hassibi, B and Calderbank,
R},
Title = {Efficient and robust compressed sensing using optimized
expander graphs},
Journal = {IEEE Transactions on Information Theory},
Volume = {55},
Number = {9},
Pages = {4299-4308},
Year = {2009},
ISSN = {0018-9448},
url = {http://dx.doi.org/10.1109/TIT.2009.2025528},
Abstract = {Expander graphs have been recently proposed to construct
efficient compressed sensing algorithms. In particular, it
has been shown that any n-dimensional vector that is
k-sparse can be fully recovered using O(k log n)
measurements and only O(k log n) simple recovery iterations.
In this paper, we improve upon this result by considering
expander graphs with expansion coefficient beyond 3\4 and
show that, with the same number of measurements, only O(k)
recovery iterations are required, which is a significant
improvement when n is large. In fact, full recovery can be
accomplished by at most 2 k very simple iterations. The
number of iterations can be reduced arbitrarily close to k,
and the recovery algorithm can be implemented very
efficiently using a simple priority queue with total
recovery time O(n log(n/k))). We also show that by
tolerating a small penalty on the number of measurements,
and not on the number of recovery iterations, one can use
the efficient construction of a family of expander graphs to
come up with explicit measurement matrices for this method.
We compare our result with other recently developed
expander-graph-based methods and argue that it compares
favorably both in terms of the number of required
measurements and in terms of the time complexity and the
simplicity of recovery. Finally, we will show how our
analysis extends to give a robust algorithm that finds the
position and sign of the k significant elements of an almost
k-sparse signal and then, using very simple optimization
techniques, finds a k-sparse signal which is close to the
best k-term approximation of the original signal. © 2009
IEEE.},
Doi = {10.1109/TIT.2009.2025528},
Key = {fds235921}
}

@article{fds235922,
Author = {Gilbert, G and Weinstein, YS and Aggarwal, V and Calderbank,
AR},
Title = {Practical quantum fault tolerance},
Journal = {Proceedings of SPIE - The International Society for Optical
Engineering},
Volume = {7342},
Year = {2009},
ISSN = {0277-786X},
url = {http://dx.doi.org/10.1117/12.818683},
Abstract = {The standard approach to quantum fault tolerance is to
calculate error thresholds on basic gates in the limit of
arbitrarily many concatenation levels. In contrast this
paper takes the number of qubits and the target
implementation accuracy as given, and provides a framework
for engineering the constrained quantum system to the
required tolerance. The approach requires solving the full
dynamics of the quantum system for an arbitrary admixture
(biased or unbiased) of Pauli errors. The inaccuracy between
ideal and implemented quantum systems is captured by the
supremum of the Schatten k-norm of the difference between
the ideal and implemented density matrices taken over all
density matrices. This is a more complete analysis than the
standard approach, where an intricate combination of worst
case assumptions and combinatorial analysis is used to
analyze the special case of equiprobable errors. Conditions
for fault tolerance are now expressed in terms of error
regions rather than a single number (the standard error
threshold). In the important special case of a stochastic
noise model and a single logical qubit, an optimization over
all 2×2 density matrices is required to obtain the full
dynamics. The complexity of this calculation is greatly
simplified through reduction to an optimization over only
three projectors. Error regions are calculated for the
standard 5- and 7-qubit codes. Knowledge of the full
dynamics makes it possible to design sophisticated
concatenation strategies that go beyond repeatedly using the
same code, and these strategies can achieve target fault
tolerance thresholds with fewer qubits. © 2009
SPIE.},
Doi = {10.1117/12.818683},
Key = {fds235922}
}

@article{fds235923,
Author = {Pezeshki, A and Calderbank, R and Scharf, LL},
Title = {Sidelobe suppression in a desired range/Doppler
interval},
Journal = {IEEE National Radar Conference - Proceedings},
Year = {2009},
ISSN = {1097-5659},
Abstract = {We present simple methods for constructing radar waveforms
whose ambiguity functions are free of sidelobes inside a
desired range or Doppler interval. We exploit the
time-frequency duality between pulse amplitude modulation
(PAM) and orthogonal frequency division multiplexing (OFDM)
to sequence Golay complementary codes across time or
frequency and clear out range/Doppler sidelobes. Proper
sequencing of complementary codes in time (PAM design)
enables the annihilation of range sidelobes along a desired
Doppler interval. The dual design, i.e., OFDM signaling of
complementary codes, enables the annihilation of Doppler
sidelobes along a desired range interval. The two designs
can be used sequentially to bring weak targets out of the
sidelobes of nearby strong reflectors inside a range-Doppler
interval of interest. ©2009 IEEE.},
Key = {fds235923}
}

@article{fds235924,
Author = {Qureshi, TR and Zoltowski, MD and Calderbank, R},
Title = {A MIMO-OFDM channel estimation scheme utilizing
complementary sequences},
Journal = {IEEE International Conference on Acoustics Speech and Signal
Processing},
Pages = {2677-2680},
Year = {2009},
ISSN = {1520-6149},
url = {http://dx.doi.org/10.1109/ICASSP.2009.4960174},
Abstract = {We present a pilot-assisted method for estimating the
frequency selective channel in a MIMO-OFDM system. The pilot
sequence is designed using the DFT of the Golay
complementary sequences. Novel exploitation of the perfect
autocorrelation property of Golay complementary sequences,
in conjunction with OSTBC based pilot waveform scheduling
across multiple OFDM frames, facilitates simple separation
of the channel mixtures at the receive antennas. The DFT
length used to transform the complementary sequence into the
frequency domain is shown to be a key critical parameter for
correctly estimating the channel. This channel estimation
scheme is then extended to antenna arrays of arbitrary
Doi = {10.1109/ICASSP.2009.4960174},
Key = {fds235924}
}

@article{fds235925,
Author = {Howard, SD and Sirianunpiboon, S and Calderbank,
AR},
Title = {Low complexity essentially maximum likelihood decoding of
perfect space-time block codes},
Journal = {IEEE International Conference on Acoustics Speech and Signal
Processing},
Pages = {2725-2728},
Year = {2009},
ISSN = {1520-6149},
url = {http://dx.doi.org/10.1109/ICASSP.2009.4960186},
Abstract = {Perfect space-time block codes (STBCs) were first introduced
by Oggier et al. to have full rate, full diversity and
non-vanishing determinant. A maximum likelihood decoder
based on the sphere decoder has been used for efficient
decoding of perfect STBCs. However the worst-case complexity
for the sphere decoder is an exhaustive search. In this
paper we present a reduced complexity algorithm for 3 x 3
perfect STBC which gives essentially maximum likelihood (ML)
performance and which can be extended to other perfect STBC.
The algorithm is based on the conditional maximization of
the likelihood function with respect to one of the set of
signal points given another. There are a number of choices
for which signal points to condition on and the underlying
structure of the code guarantees that one of the choices is
good with high probability. Furthermore, the approach can be
integrated with the sphere decoding algorithm with worst
case complexity corresponding exactly to that of our
Doi = {10.1109/ICASSP.2009.4960186},
Key = {fds235925}
}

@article{fds235926,
Author = {Aggarwal, V and Sankar, L and Calderbank, AR and Poor,
HV},
Title = {Secrecy capacity of a class of orthogonal relay eavesdropper
channels},
Journal = {Information Theory and Applications Workshop, ITA
2009},
Pages = {295-300},
Year = {2009},
url = {http://dx.doi.org/10.1109/ITA.2009.5044960},
Abstract = {The secrecy capacity is developed for a class of relay
channels with orthogonal components and a passive
eavesdropper node. The relay and destination receive signals
from the source on two orthogonal channels such that the
destination also receives transmissions from the relay on
its channel. The eavesdropper can overhear either one or
both of the orthogonal channels. Inner and outer bounds on
the secrecy capacity are developed for both the discrete
memoryless and the Gaussian channel models. For the discrete
memoryless case, the secrecy capacity is shown to be
achieved by a partial decode-and-forward (PDF) scheme when
the eavesdropper can overhear only one of the two orthogonal
channels. Two new outer bounds are presented for the
Gaussian model using recent capacity results for a Gaussian
multi-antenna channel with a multi-antenna eavesdropper. The
outer bounds are shown to be tight for two sub-classes of
channels. The first sub-class is one in which the source and
relay are clustered and the eavesdropper overhears on only
one of the two channels for which the PDF strategy is
optimal. The second is a sub-class in which the source does
not transmit to the relay for which a noise-forwarding
strategy is optimal. © 2009 IEEE.},
Doi = {10.1109/ITA.2009.5044960},
Key = {fds235926}
}

@article{fds235927,
Author = {Wu, Y and Davis, LM and Calderbank, R},
Title = {On the capacity of the discrete-time channel with uniform
output quantization},
Journal = {IEEE International Symposium on Information Theory -
Proceedings},
Pages = {2194-2198},
Year = {2009},
url = {http://dx.doi.org/10.1109/ISIT.2009.5205826},
Abstract = {This paper provides new insight into the classical problem
of determining both the capacity of the discrete-time
channel with uniform output quantization and the capacity
achieving input distribution. It builds on earlier work by
Gallager and Witsenhausen to provide a detailed analysis of
two particular quantization schemes. The first is saturation
quantization where overflows are mapped to the nearest
quantization bin, and the second is modulo quantization
where overflows are mapped to the nearest quantization bin
after reduction by some modulus. Both the capacity of modulo
quantization and the capacity achieving input distribution
are determined. When the additive noise is gaussian and
relatively small, the capacity of saturation quantization is
shown to be bounded below by that of modulo quantization. In
the limit of arbitrarily many uniform quantization levels,
it is shown that the difference between the upper and lower
bounds on capacity given by Ihara is only 0.26 bits. © 2008
IEEE.},
Doi = {10.1109/ISIT.2009.5205826},
Key = {fds235927}
}

@article{fds235928,
Author = {Aggarwal, V and Lai, L and Calderbank, AR and Poor,
HV},
Title = {Wiretap channel type II with an active eavesdropper},
Journal = {IEEE International Symposium on Information Theory -
Proceedings},
Pages = {1944-1948},
Year = {2009},
url = {http://dx.doi.org/10.1109/ISIT.2009.5205631},
Abstract = {The wiretap channel type II with an active eavesdropper is
considered in this paper. Compared with the eavesdropper
model considered in much of the literature, the eavesdropper
considered here can not only overhear but also modify the
signal transmitted over the channel. Two modification
modelsare considered. In the first model, the eavesdropper
erases the bits it observes. In the second model, the
eavesdropper modifies the bits it observes. For this channel
with memory (introduced bythe activity of the eavesdropper),
one should conduct the worst case scenario analysis. Novel
concatenated coding schemes that provide perfect security
for the communications are developed for both models to give
bounds on the achievable secrecy rate. The technique to
modify the inner code to maintain the secrecyproperties of
the outer code may be of independent interest. © 2009
IEEE.},
Doi = {10.1109/ISIT.2009.5205631},
Key = {fds235928}
}

@article{fds235929,
Author = {Hande, P and Chiang, M and Calderbank, R and Rangan,
S},
Title = {Network pricing and rate allocation with content provider
participation},
Journal = {Proceedings - IEEE INFOCOM},
Pages = {990-998},
Year = {2009},
ISSN = {0743-166X},
url = {http://dx.doi.org/10.1109/INFCOM.2009.5062010},
Abstract = {Pricing content-providers for connectivity to endusers and
setting connection parameters based on the price is an
evolving model on the Internet. The implications are heavily
debated in telecom policy circles, and some advocates of
"Network Neutrality" have opposed price based
differentiation in connectivity. However, pricing content
providers can possibly subsidize the end-user's cost of
connectivity, and the consequent increase in end-user demand
can benefit ISPs and content providers. This paper provides
a framework to quantify the precise trade-off in the
distribution of benefits among ISPs, content-providers, and
end-users. The framework generalizes the well-known utility
maximization based rate allocation model, which has been
extensively studied as an interplay between the ISP and the
end-users, to incorporate pricing of content-providers. We
derive the resulting equilibrium prices and data rates in
two different ISP market conditions: competition and
monopoly. Network neutrality based restriction on
content-provider pricing is then modeled as a constraint on
the maximum price that can be charged to content-providers.
We demonstrate that, in addition to gains in total and
enduser surplus, content-provider experiences a net surplus
from participation in rate allocation under low cost of
connectivity. The surplus gains are, however, limited under
monopoly conditions in comparison to competition in the ISP
market. © 2009 IEEE.},
Doi = {10.1109/INFCOM.2009.5062010},
Key = {fds235929}
}

@article{fds235930,
Author = {Calderbank, R and Casazza, PG and Heinecke, A and Kutyniok, G and Pezeshki, A},
Title = {Constructing fusion frames with desired parameters},
Journal = {Proceedings of SPIE - The International Society for Optical
Engineering},
Volume = {7446},
Year = {2009},
ISSN = {0277-786X},
url = {http://dx.doi.org/10.1117/12.825782},
Abstract = {A fusion frame is a frame-like collection of subspaces in a
Hilbert space. It generalizes the concept of a frame system
for signal representation. In this paper, we study the
existence and construction of fusion frames. We first
introduce two general methods, namely the spatial complement
and the Naimark complement, for constructing a new fusion
frame from a given fusion frame. We then establish existence
conditions for fusion frames with desired properties. In
particular, we address the following question: Given M, N, m
∈ N and {λj}Mj =1, does there exist a fusion frame in RM
with N subspaces of dimension m for which {λj} Mj =1are the
eigenvalues of the associated fusion frame operator? We
address this problem by providing an algorithm which
computes such a fusion frame for almost any collection of
parameters M, N, m ∈ N and {λj}Mj =1. Moreover, we show
how this procedure can be applied, if subspaces are to be
added to a given fusion frame to force it to become tight.©
2009 SPIE.},
Doi = {10.1117/12.825782},
Key = {fds235930}
}

@article{fds235931,
Author = {Aggarwal, V and Sankar, L and Calderbank, AR and Poor,
HV},
Title = {Information secrecy from multiple eavesdroppers in
orthogonal relay channels},
Journal = {IEEE International Symposium on Information Theory -
Proceedings},
Pages = {2607-2611},
Year = {2009},
url = {http://dx.doi.org/10.1109/ISIT.2009.5205963},
Abstract = {The secrecy capacity of relay channels with orthogonal
components is studied in the presence of additional passive
eavesdropper nodes. The relay and destination receive
signals from the source on two orthogonal channels such that
the destination also receives transmissions from the relay
on its channel. The eavesdropper(s) can overhear either one
or both of the orthogonal channels. For a single
eavesdropper node, the secrecy capacity is shown to be
achieved by a partial decodeand-forward (PDF) scheme when
the eavesdropper can overhear only one of the two orthogonal
channels. For the case of two eavesdropper nodes, secrecy
capacity is shown to be achieved by PDF for a sub-class of
channels. © 2009 IEEE.},
Doi = {10.1109/ISIT.2009.5205963},
Key = {fds235931}
}

@article{fds235932,
Author = {Wu, Y and Calderbank, R},
Title = {Construction of high rate super-orthogonal space-time block
codes},
Journal = {Conference Record - International Conference on
Communications},
Year = {2009},
ISSN = {0536-1486},
url = {http://dx.doi.org/10.1109/ICC.2009.5198848},
Abstract = {It is standard practice to integrate outer trellis codes
with inner space-time block codes to increase coding gain,
but the drawback is a decrease in rate. Jafarkhani and
Seshadri [1] have introduced an alternative method of
combining multiple inner orthogonal space-time codes with
outer trellis codes that both preserves rate and increases
coding gain. However their work is limited to orthogonal
codes, for which the achievable rate is typically low. This
paper presents a method of achieving higher transmission
rates by integrating higher rate non-orthogonal space with
outer trellis codes, and new methods are introduced to avoid
catastrophic codes. The method is presented with reference
to the particular example of the Silver Code, but it applies
to all multiplexed orthogonal designs and to more general
Doi = {10.1109/ICC.2009.5198848},
Key = {fds235932}
}

@article{fds235933,
Author = {Aggarwal, V and Calderbank, R and Gilbert, G and Weinstein,
YS},
Title = {Engineering fault tolerance for realistic quantum systems
via the full error dynamics of quantum codes},
Journal = {IEEE International Symposium on Information Theory -
Proceedings},
Pages = {958-962},
Year = {2009},
url = {http://dx.doi.org/10.1109/ISIT.2009.5205593},
Abstract = {The standard approach to quantum fault tolerance is to
calculate error thresholds on basic gates in the limit of
arbitrarily many concatenation levels. In contrast this
paper takes the number of qubits and the target
implementation accuracy as given, and provides a framework
for engineering the constrained quantum system to the
required tolerance. The approach requires solving the full
dynamics of the quantum system for an arbitrary admixture
(biased or unbiased) of Pauli errors. The inaccuracy between
ideal and implemented quantum systems is captured by the
supremum of the Schatten-k norm of the difference between
the ideal and implemented density matrices taken over all
density matrices. This is a more complete analysis than the
standard approach, where an intricate combination of worst
case assumptions and combinatorial analysis is used to
analyze the special case of equiprobable errors. Conditions
for fault tolerance are now expressed in terms of error
regions rather than a single number (the standard error
threshold). In the important special case of a stochastic
noise model and a single logical qubit, an optimization over
all 2 × 2 density matrices is required to obtain the full
dynamics. The complexity of this calculation is greatly
simplified through reduction to an optimization over only
three projectors. Error regions are calculated for the
standard 5- and 7-qubit codes. Knowledge of the full
dynamics makes it possible to design sophisticated
concatenation strategies that go beyond repeatedly using the
same code, and these strategies can achieve target fault
tolerance thresholds with fewer qubits. © 2009
IEEE.},
Doi = {10.1109/ISIT.2009.5205593},
Key = {fds235933}
}

@article{fds235934,
Author = {Wu, Y and Jia, T and Calderbank, R and Duel-Hallen, A and Hallen,
H},
Title = {Integration of code diversity and long-range channel
prediction in wireless communication},
Journal = {Proceedings of the 2009 International Conference on
Electromagnetics in Advanced Applications, ICEAA
'09},
Pages = {241-244},
Year = {2009},
url = {http://dx.doi.org/10.1109/ICEAA.2009.5297458},
Abstract = {Code diversity integrates space-time coding with beamforming
by using a small number of feedback bits to select from a
family of space-time codes. Different codes lead to
different induced channels at the receiver, where Channel
State information (CSI) is used to instruct the transmitter
how to choose the code. Feedback can be combined with
sub-optimal low complexity decoding of the component codes
to match Maximum-Likelihood (ML) decoding performance of any
individual code in the family. It can also be combined with
ML decoding of the component codes to improve performance
beyond ML decoding performance of any individual code. Prior
analysis of code diversity did not take into account the
effect of the mobile speed and the delay in the feedback
channel. This paper demonstrates the practicality of code
diversity in space-time coded systems by showing that
predicted performance gains based on instantaneous feedback
are largely preserved when the feedback is based on
long-range prediction of rapidly time-varying correlated
fading channels. Simulations are presented for two channel
models; the first is the Jakes model where angles of arrival
are uniformly distributed and the arrival rays have equal
strengths, and the second is a model derived from a physical
scattering environment where the parameters associated with
the reflectors vary in time and the arrival rays have
different strengths and non-symmetric arrival angles. ©
2009 IEEE.},
Doi = {10.1109/ICEAA.2009.5297458},
Key = {fds235934}
}

@article{fds235935,
Author = {Aggarwal, V and Applebaum, L and Bennatan, A and Calderbank, AR and Howard, SD and Searle, SJ},
Title = {Enhanced CDMA communications using compressed-sensing
reconstruction methods},
Journal = {2009 47th Annual Allerton Conference on Communication,
Control, and Computing, Allerton 2009},
Pages = {1211-1215},
Year = {2009},
url = {http://dx.doi.org/10.1109/ALLERTON.2009.5394537},
Abstract = {We propose a simple method for downlink communications based
on second order Reed-Muller sequences which generalize the
Walsh sequences that are used in orthogonal CDMA. In our
approach, coding occurs at the chip level (i.e. we use a
spreading factor of 1) and different users are not
orthogonalized. Our decoding algorithm is borrowed from work
on fast reconstruction of signals for compressed-sensing.
This algorithm allows for low-complexity multiuser
Doi = {10.1109/ALLERTON.2009.5394537},
Key = {fds235935}
}

@article{fds235936,
Author = {Qureshi, TR and Zoltowski, MD and Calderbank, R},
Title = {Target detection in MIMO radar using Golay complementary
sequences in the presence of doppler},
Journal = {2009 47th Annual Allerton Conference on Communication,
Control, and Computing, Allerton 2009},
Pages = {1490-1493},
Year = {2009},
url = {http://dx.doi.org/10.1109/ALLERTON.2009.5394498},
Abstract = {In this paper, we present a method for detecting a point
target using multiple antennas when the relative motion
between the receivers and the target induces a
non-negligible Doppler shift. As a key illustrative example,
we consider a 4 x 4 system employing a unitary matrix
waveform set, e.g., formed from Golay complementary
sequences. When a non-negligible Doppler shift is induced by
the target motion, the waveform matrix formed from the
complementary sequences is no longer unitary, resulting in
significantly degraded target range estimates. To solve this
problem, we adopt a subspace based approach exploiting the
observation that the receive matrix formed from matched
filtering of the reflected waveforms has a (non-trivial)
null-space. Through processing of the waveforms with the
appropriate vector from the null-space, we can significantly
improve the detection performance. We provide simulation
results to confirm the theoretical analysis. ©2009
IEEE.},
Doi = {10.1109/ALLERTON.2009.5394498},
Key = {fds235936}
}

@article{fds235937,
Author = {Calderbank, R and Howard, S and Jafarpour, S},
Title = {A sublinear algorithm for sparse reconstruction with
ℓ2/ ℓ2 recovery
guarantees},
Journal = {CAMSAP 2009 - 2009 3rd IEEE International Workshop on
Processing},
Pages = {209-212},
Year = {2009},
url = {http://dx.doi.org/10.1109/CAMSAP.2009.5413298},
Abstract = {Compressed Sensing aims to capture attributes of a sparse
signal using very few measurements. Candès and Tao showed
that sparse reconstruction is possible if the sensing matrix
acts as a near isometry on all k-sparse signals. This
property holds with overwhelming probability if the entries
of the matrix are generated by an iid Gaussian or Bernoulli
process. There has been significant recent interest in an
alternative signal processing framework; exploiting
deterministic sensing matrices that with overwhelming
probability act as a near isometry on k-sparse vectors with
uniformly random support, a geometric condition that is
called the Statistical Restricted Isometry Property or
StRIP. This paper considers a family of deterministic
sensing matrices satisfying the StRIP that are based on
Delsarte-Goethals Codes codes (binary chirps) and a k-sparse
reconstruction algorithm with sublinear complexity. In the
presence of stochastic noise in the data domain, this paper
derives bounds on the ℓ2 accuracy of approximation in
terms of the ℓ2 norm of the measurement noise and the
accuracy of the best k-sparse approximation, also measured
in the ℓ2 norm. This type of ℓ2/ℓ2 bound is tighter
than the standard ℓ2/ℓ1 or ℓ1/ℓ1 bounds. © 2009
IEEE.},
Doi = {10.1109/CAMSAP.2009.5413298},
Key = {fds235937}
}

@article{fds235938,
Author = {Bollapalli, KC and Wu, Y and Gulati, K and Khatri, S and Calderbank,
AR},
Title = {Highly parallel decoding of space-time codes on graphics
processing units},
Journal = {2009 47th Annual Allerton Conference on Communication,
Control, and Computing, Allerton 2009},
Pages = {1262-1269},
Year = {2009},
url = {http://dx.doi.org/10.1109/ALLERTON.2009.5394528},
Abstract = {Graphics Processing Units (GPUs) with a few hundred
extremely simple processors represent a paradigm shift for
highly parallel computations. We use this emergent GPU
architecture to provide a first demonstration of the
feasibility of real time ML decoding (in software) of a high
rate space-time block code that is representative of codes
incorporated in 4th generation wireless standards such as
WiMAX and LTE. The decoding algorithm is conditional
optimization which reduces to a parallel calculation that is
a natural fit to the architecture of low cost
GPUs.Experimental results demonstrate that asymptotically
the GPU implementation is more than 700 times faster than a
standard serial implementation. These results suggest that
GPU architectures have the potential to improve the cost /
performance tradeoff of 4th generation wireless base
stations. Additional benefits might include reducing the
time required for system development and the time required
for configuration and testing of wireless base stations.
Doi = {10.1109/ALLERTON.2009.5394528},
Key = {fds235938}
}

@article{fds235939,
Author = {Chi, Y and Calderbank, R and Pezeshki, A},
Title = {Golay complementary waveforms for sparse delay-Doppler radar
imaging},
Journal = {CAMSAP 2009 - 2009 3rd IEEE International Workshop on
Processing},
Pages = {177-180},
Year = {2009},
url = {http://dx.doi.org/10.1109/CAMSAP.2009.5413308},
Abstract = {We present a new approach to radar imaging that exploits
sparsity in the matched filter domain to enable high
resolution imaging of targets in delay and Doppler. We show
that the vector of radar cross-ambiguity values at any fixed
test delay cell has a sparse representation in a Vandermonde
frame that is obtained by discretizing the Doppler axis. The
expansion coefficients are given by the auto-correlation
functions of the transmitted waveforms. We show that the
orthogonal matching pursuit (OMP) algorithm can then be
easily used to identify the locations of the radar targets
in delay and Doppler. Unambiguous imaging in delay is
enabled by alternating between a Golay pair of phase coded
waveforms at the transmission to eliminate delay sidelobe
effects. We then extend our work to multi-channel radar, by
developing a sparse recovery approach for
dually-polarimetric radar. We exploit sparsity in a bank of
matched filters, each of which is matched to an entry of an
Alamouti matrix of Golay waveforms to recover a co-polar or
cross-polar polarization scattering component. © 2009
IEEE.},
Doi = {10.1109/CAMSAP.2009.5413308},
Key = {fds235939}
}

@article{fds235940,
Author = {Sirianunpiboon, S and Howard, SD and Calderbank, AR and Davis,
LM},
Title = {Fully-polarimetric MIMO to improve throughput and
reliability across propagation conditions},
Journal = {IEEE VTS ... Vehicular Technology Conference : VTC :
[proceedings]},
Year = {2009},
ISSN = {1550-2252},
url = {http://dx.doi.org/10.1109/VETECF.2009.5379016},
Abstract = {Multiple-Input Multiple-Output (MIMO) functionality has been
shown to dramatically increase the capacity of wireless
communication systems when the environment provides rich
multipath scattering. In a predominantly Line-of-Sight (LOS)
environment, the loss of diversity reduces the potential
gain considerably. This can be remedied in part by the use
of dual-polarized antennas, which increases the rank of the
wireless channel and introduces diversity, while minimizing
the antenna's form factor. However the performance of a
dual-polarized antenna is still degraded by antenna
rotations that are typical of mobile terminal operation.
This paper presents a solution which uses a triad antenna at
the transmitter and a triad at the receiver, to provide a
8-10 dB gain over the baseline dual-polarized system. A
triad is composed of three orthogonal dipoles oriented in
perpendicular directions. A triad antenna can generate an
arbitrary oscillating dipole moment at the transmitter and
consequently an arbitrary polarized electric field at the
receiver, subject only to the constraints imposed by the
physics of the Electromagnetic (EM) field. We show that, in
LOS environments, the capacity of the channel is invariant
under arbitrary rotations of the transmit and/or receive
antennas about their centres. Simulation results show that
the performance is stable as the propagation environment
varies from rich scattering to pure LOS. A full rate 3×3
Space-Time Block Code (STBC) is proposed for the triad
system that is designed for low complexity decoding. © 2009
Crown.},
Doi = {10.1109/VETECF.2009.5379016},
Key = {fds235940}
}

@article{fds235941,
Author = {Jafarpour, S and Willett, R and Raginsky, M and Calderbank,
R},
Title = {Performance bounds for expander-based compressed sensing in
the presence of Poisson noise},
Journal = {Conference Record of the Asilomar Conference on Signals,
Systems and Computers},
Pages = {513-517},
Year = {2009},
ISSN = {1058-6393},
url = {http://dx.doi.org/10.1109/ACSSC.2009.5469879},
Abstract = {This paper provides performance bounds for compressed
sensing in the presence of Poisson noise using expander
graphs. The Poisson noise model is appropriate for a variety
of applications, including low-light imaging and digital
streaming, where the signal-independent and/or bounded noise
models used in the compressed sensing literature are no
longer applicable. In this paper, we develop a novel sensing
paradigm based on expander graphs and propose a MAP
algorithm for recovering sparse or compressible signals from
Poisson observations. The geometry of the expander graphs
and the positivity of the corresponding sensing matrices
play a crucial role in establishing the bounds on the signal
reconstruction error of the proposed algorithm. The geometry
of the expander graphs makes them provably superior to
random dense sensing matrices, such as Gaussian or partial
Fourier ensembles, for the Poisson noise model.We support
our results with experimental demonstrations. © 2009
IEEE.},
Doi = {10.1109/ACSSC.2009.5469879},
Key = {fds235941}
}

@article{fds235942,
Author = {Sirianunpiboon, S and Howard, SD and Calderbank,
AR},
Title = {A scheme for fully polarimetric MIMO multiuser
detection},
Journal = {Conference Record of the Asilomar Conference on Signals,
Systems and Computers},
Pages = {1461-1465},
Year = {2009},
ISSN = {1058-6393},
url = {http://dx.doi.org/10.1109/ACSSC.2009.5470081},
Abstract = {Multiple-Input Multiple-Output (MIMO) functionality has been
shown to dramatically increase the capacity of wireless
communication systems when the environment provides rich
multipath scattering. In a predominantly Line-of-Sight (LOS)
environment, the loss of diversity reduces the potential
gain considerably. Recent studies have shown that systems
which use a fully -polarimetric antenna such as triad
antenna at the both end of the link can provides stability
in performance across a full range of propagation
environments from LOS to pure Rayleigh scattering. These
systems also provide resilience to arbitrary rotations of
the transmit and receive antennas. This paper considers the
multiuser downlink where both the base station and each user
is equipped with a triad antenna. The system uses a CDMA
transmitting scheme in which each user is assigned a two
dimensional subspace and the transmitted information symbol
for each user is coded across this subspace. The received
signal for each user after despreading is equivalent to the
decoding problem of a single user with space-time block code
(STBC) system. We demonstrate that the transmitted
information symbols can be chosen to have the structure of
STBC with full rate, full-diversity and low complexity
decoding. We also show how to generalize our basic MIMO CDMA
scheme to apply to an inhomogeneous multiuser scenario where
the base station has two transmit antennas, but each user is
equipped with either one or two receive antennas and wish to
use different STBCs. © 2009 IEEE.},
Doi = {10.1109/ACSSC.2009.5470081},
Key = {fds235942}
}

@article{fds235943,
Author = {Qureshi, T and Zoltowski, M and Calderbank, R},
Title = {Target detection in MIMO radar using golay complementary
sequences in the presence of doppler},
Journal = {Conference Record of the Asilomar Conference on Signals,
Systems and Computers},
Pages = {156-159},
Year = {2009},
ISSN = {1058-6393},
url = {http://dx.doi.org/10.1109/ACSSC.2009.5470143},
Abstract = {In this paper, we present a method for detecting a point
target using multiple antennas when the relative motion
between the receivers and the target induces a non-trivial
Doppler shift. We consider a 4×4 system employing sets of
unitary waveforms. In case of a non-trivial Doppler shift
induced by the target motion, the waveforms are no longer
unitary, and unambiguous target ranging is not possible. To
solve this problem, we adopt a subspace based approach where
we show that the unitary waveforms used have a non-empty
null-space under certain conditions, and by processing the
waveforms with vectors from the null-space, we can
significantly improve the detection performance. © 2009
IEEE.},
Doi = {10.1109/ACSSC.2009.5470143},
Key = {fds235943}
}

@article{fds235944,
Author = {Lau, C and Zoltowski, M and Calderbank, R},
Title = {Spatio-temporal scheduling of complementary sequences with
application to MIMO-OFDM},
Journal = {Conference Record of the Asilomar Conference on Signals,
Systems and Computers},
Pages = {503-507},
Year = {2009},
ISSN = {1058-6393},
url = {http://dx.doi.org/10.1109/ACSSC.2009.5469876},
Abstract = {In this paper, a new method of space-time processing is
proposed for Orthogonal Frequency Division Multiplexing
(OFDM) using complementary sequences derived from the rows
of the DFT matrix. The autocorrelative properties of the
complementary sequences allows multiple complex data signals
at the transmitter with an arbitrary number of antennas to
be perfectly separated at the receiver without prior channel
knowledge while achieving full-rate. This new method is
proposed and derived for multiple MIMO-OFDM systems with
multipath fading; at the receiver, symbol estimation is
effected via maximum likelhihood estimation (ML). © 2009
IEEE.},
Doi = {10.1109/ACSSC.2009.5469876},
Key = {fds235944}
}

@article{fds235945,
Author = {Applebaum, L and Howard, SD and Searle, S and Calderbank,
R},
Title = {Chirp sensing codes: Deterministic compressed sensing
measurements for fast recovery},
Journal = {Applied and Computational Harmonic Analysis},
Volume = {26},
Number = {2},
Pages = {283-290},
Year = {2009},
ISSN = {1063-5203},
url = {http://dx.doi.org/10.1016/j.acha.2008.08.002},
Abstract = {Compressed sensing is a novel technique to acquire sparse
signals with few measurements. Normally, compressed sensing
uses random projections as measurements. Here we design
deterministic measurements and an algorithm to accomplish
signal recovery with computational efficiency. A measurement
matrix is designed with chirp sequences forming the columns.
Chirps are used since an efficient method using FFTs can
recover the parameters of a small superposition. We show
that this type of matrix is valid as compressed sensing
measurements. This is done by bounding the eigenvalues of
sub-matrices, as well as an empirical comparison with random
projections. Further, by implementing our algorithm,
simulations show successful recovery of signals with
sparsity levels similar to those possible by matching
pursuit with random measurements. For sufficiently sparse
signals, our algorithm recovers the signal with
computational complexity O (K log K) for K measurements.
This is a significant improvement over existing algorithms.
Doi = {10.1016/j.acha.2008.08.002},
Key = {fds235945}
}

@article{fds235946,
Author = {Bennatan, A and Aggarwal, V and Wu, Y and Calderbank, AR and Hoydis, J and Chindapol, A},
Title = {Bounds and lattice-based transmission strategies for the
Journal = {IEEE Transactions on Wireless Communications},
Volume = {8},
Number = {7},
Pages = {3620-3627},
Year = {2009},
ISSN = {1536-1276},
url = {http://dx.doi.org/10.1109/TWC.2009.080569},
Abstract = {We consider a fading version of the dirty-paper problem, as
proposed by Grover and Sahai. In this formulation, the
various signals involved are complex-valued, and the
interference (known only to the transmitter) is multiplied
by a random complex-valued coefficient, whose phase is known
only to the receiver. We focus on a compound channel
formulation, and seek to maximize the worst-case
performance. We present an achievable strategy modeled on
the lattice-based approach of Erez, Shamai and Zamir and
propose heuristic methods to optimize its parameters. We
also derive an upper bound on the maximum achievable
transmission rates. Our bounds are shown to be tight in some
settings, yielding a complete characterization of capacity.
We also provide simulation results, indicating the practical
effectiveness of our approaches. © 2009
IEEE.},
Doi = {10.1109/TWC.2009.080569},
Key = {fds235946}
}

@article{fds235947,
Author = {Rabiei, P and Al-Dhahir, N and Calderbank, R},
Title = {New rate-2 STBC design for 2 TX with reduced-complexity
maximum likelihood decoding},
Journal = {IEEE Transactions on Wireless Communications},
Volume = {8},
Number = {4},
Pages = {1803-1813},
Year = {2009},
ISSN = {1536-1276},
url = {http://dx.doi.org/10.1109/TWC.2009.071323},
Abstract = {We propose a new full-rate space-time block code (STBC) for
two transmit antennas which can be designed to achieve
maximum diversity or maximum capacity while enjoying
optimized coding gain and reduced-complexity
maximum-likelihood (ML) decoding. The maximum transmit
diversity (MTD) construction provides a diversity order of
2N r for any number of receive antennas N r at the cost of
channel capacity loss. The maximum channel capacity (MCC)
construction preserves the mutual information between the
transmit and the received vectors while sacrificing
diversity. The system designer can switch between the two
constructions through a simple parameter change based on the
operating signal-to-noise ratio (SNR), signal constellation
size and number of receive antennas. Thanks to their special
algebraic structure, both constructions enjoy low-complexity
ML decoding proportional to the square of the signal
constellation size making them attractive alternatives to
existing full-diversity full-rate STBCs in [6], [3] which
have high ML decoding complexity proportional to the fourth
order of the signal constellation size. Furthermore, we
design a differential transmission scheme for our proposed
STBC, derive the exact ML differential decoding rule, and
compare its performance with competitive schemes. Finally,
we investigate transceiver design and performance of our
proposed STBC in spatial multiple-access scenarios and over
frequency-selective channels. © 2006 IEEE.},
Doi = {10.1109/TWC.2009.071323},
Key = {fds235947}
}

@article{fds235948,
Author = {Wu, Y and Davis, LM and Calderbank, AR},
Title = {Finite precision analysis for space-time
decoding},
Journal = {IEEE Transactions on Signal Processing},
Volume = {57},
Number = {12},
Pages = {4861-4870},
Year = {2009},
ISSN = {1053-587X},
url = {http://dx.doi.org/10.1109/TSP.2009.2026068},
Abstract = {Low complexity optimal (or nearly optimal) decoders for
space-time codes have recently been under intensive
investigation. For example, recent works by Sirianunpiboon
and others show that the Silver code and the Golden code can
be decoded optimally (or nearly optimally) with quadratic
decoding complexity. Fast decodability makes them very
attractive in practice. In implementing these decoders,
floating-point to fixed-point conversion (FFC) needs to be
carefully undertaken to minimize hardware cost while
retaining decoding performance. The process of quantization
for fixed-point representations is often ignored by research
community and lacks investigation, and so FFC is often
conducted heuristically based on simulations. This paper
studies the effects of quantization to space-time coded
systems from an information theoretic perspective. It shows
the analytical relationship between quantization error and
decoding performance deterioration. This paper also proposes
a general finite precision implementation methodology
including two FFC criteria for space-time coded systems
within an integer optimization framework. As a particular
example, this paper examines the finite precision
implementation of the quadratic optimal decoding algorithm
of the Silver code. However, our methodology and techniques
can be applied to general space-time codes. © 2009
IEEE.},
Doi = {10.1109/TSP.2009.2026068},
Key = {fds235948}
}

@article{fds235949,
Author = {Matz, G and Calderbank, R and Mecklenbrauker, C and Naguib, A and Viterbo, E},
Title = {Introduction to the issue on managing complexity in
multiuser MIMO systems},
Journal = {IEEE Journal of Selected Topics in Signal
Processing},
Volume = {3},
Number = {6},
Pages = {906-909},
Year = {2009},
ISSN = {1932-4553},
url = {http://dx.doi.org/10.1109/JSTSP.2009.2036955},
Doi = {10.1109/JSTSP.2009.2036955},
Key = {fds235949}
}

@article{fds235950,
Author = {Wu, Y and Calderbank, R},
Title = {Code diversity in multiple antenna wireless
communication},
Journal = {IEEE Journal of Selected Topics in Signal
Processing},
Volume = {3},
Number = {6},
Pages = {928-938},
Year = {2009},
ISSN = {1932-4553},
url = {http://dx.doi.org/10.1109/JSTSP.2009.2035861},
Abstract = {The standard approach to the design of individual space-time
codes is based on optimizing diversity and coding gains.
This geometric approach leads to remarkable examples, such
as perfect space-time block codes (Perfect space-time block
codes. F. Oggier , Trans. Inf. Theory, vol. 52, no. 9, pp.
38853902, Sep. 2006), for which the complexity of
maximum-likelihood (ML) decoding is considerable. Code
diversity is an alternative and complementary approach where
a small number of feedback bits are used to select from a
family of space-time codes. Different codes lead to
different induced channels at the receiver, where channel
state information (CSI) is used to instruct the transmitter
how to choose the code. This method of feedback provides
gains associated with beamforming while minimizing the
number of feedback bits. Thus, code diversity can be viewed
as the integration of space-time coding with a fixed set of
beams. It complements the standard approach to code design
by taking advantage of different (possibly equivalent)
realizations of a particular code design. Feedback can be
combined with suboptimal low-complexity decoding of the
component codes to match ML decoding performance of any
individual code in the family. It can also be combined with
ML decoding of the component codes to improve performance
beyond ML decoding performance of any individual code. One
method of implementing code diversity is the use of feedback
to adapt the phase of a transmitted signal. The values of
code diversity is verified in the simulations on 4 × 4
Quasi-Orthogonal space-time Block Code (QOSTBC), multi-user
detection of Alamouti signaling and the Golden code. It
shows that our code diversity scheme is more robust in the
case of erroneous feedback compared with other low-rate
feedback schemes such as transmit antenna selection and its
variations. This paper introduces a family of full rate
circulant codes which can be linearly decoded by Fourier
decomposition of circulant matrices within the code
diversity framework. © 2009 IEEE.},
Doi = {10.1109/JSTSP.2009.2035861},
Key = {fds235950}
}

@article{fds235951,
Author = {Aggarwal, V and Sankar, L and Calderbank, AR and Poor,
HV},
Title = {Ergodic layered erasure one-sided interference
channels},
Journal = {2009 IEEE Information Theory Workshop, ITW
2009},
Pages = {574-578},
Year = {2009},
url = {http://dx.doi.org/10.1109/ITW.2009.5351176},
Abstract = {The sum capacity of a class of layered erasure onesided
interference channels is developed under the assumption of
no channel state information at the transmitters. Outer
bounds are presented for this model and are shown to be
tight for the following sub-classes: i) weak, ii) strong
(mix of strong but not very strong (SnVS) and very strong
(VS)), iii) ergodic very strong (mix of strong and weak),
and (iv) a sub-class of mixed interference (mix of SnVS and
weak). Each sub-class is uniquely defined by the fading
statistics. © 2009 IEEE.},
Doi = {10.1109/ITW.2009.5351176},
Key = {fds235951}
}

@article{fds235777,
Author = {Zoltowski, MD and Qureshi, TR and Calderbank, R and Moran,
B},
Title = {Unitary Design of Radar Waveform Diversity
Sets},
Journal = {Handbook on Array Processing and Sensor Networks},
Pages = {211-230},
Year = {2010},
url = {http://dx.doi.org/10.1002/9780470487068.ch7},
Doi = {10.1002/9780470487068.ch7},
Key = {fds235777}
}

@article{fds235952,
Author = {Li, Y and Li, Z and Chiang, M and Calderbank, AR},
Title = {Intelligent video network engineering with distributed
optimization: Two case studies},
Journal = {Studies in Computational Intelligence},
Volume = {280},
Pages = {253-290},
Year = {2010},
ISSN = {1860-949X},
url = {http://dx.doi.org/10.1007/978-3-642-11686-5_8},
Abstract = {Video is becoming the dominant traffic over the Internet. To
provide better Quality of Service (QoS) to the end users,
while also achieve network resource efficiency, is an
important problem for both network operators, content
providers and consumers. In this work, we present
intelligent video networking solutions for IPTV and
Peer-to-Peer (P2P) systems that optimizes the users' QoS
experiences while under network resource constraints. Given
the limited network bandwidth resources, how to provide
Internet users with good video playback Quality of Service
(QoS) is a key problem. For IPTV systems video clips
competing bandwidth, we propose an approach of Content-Aware
distortion-Fair (CAF) video delivery scheme, which is aware
of the characteristics of video frames and ensures max-min
distortion fair sharing among video flows. Different from
bandwidth fair sharing, CAF targets end-to-end video
playback quality fairness among users when bandwidth is
insufficient, based on the fact that users directly care
about video quality rather than bandwidth. The proposed CAF
approach does not require rate-distortion modeling of the
source, which is difficult to estimate, but instead, it
exploits the temporal prediction structure of the video
sequences along with a frame drop distortion metric to guide
resource allocations and coordination. Experimental results
show that the proposed approach operates with limited
overhead in computation and communication, and yields better
QoS, especially when the network is congested. For Internet
based video broadcasting applications such as IPTV, the
Peer-to-Peer (P2P) streaming scheme has been found to be an
effective solution. An important issue in live broadcasting
is to avoid playback buffer underflow. How to utilize the
playback buffer and upload bandwidth of peers to minimize
the freeze-ups in playback, is the problem we try to solve.
We propose a successive water-filling (SWaF) algorithm for
the video transmission scheduling in P2P live streaming
system, to minimize the playback freeze-ups among peers.
SWaF algorithm only needs each peer to optimally transmit
(within its uploading bandwidth) part of its available video
segments in the buffer to other peers requiring the content
and pass small amount message to some other peers. Moreover,
SWaF has low complexity and provable optimality. Numerical
results demonstrated the effectiveness of the proposed
algorithm. © 2010 Springer-Verlag Berlin
Heidelberg.},
Doi = {10.1007/978-3-642-11686-5_8},
Key = {fds235952}
}

@article{fds235953,
Author = {Hande, P and Chiang, M and Calderbank, R and Zhang,
J},
Title = {Pricing under constraints in access networks: Revenue
maximization and congestion management},
Journal = {Proceedings - IEEE INFOCOM},
Year = {2010},
ISSN = {0743-166X},
url = {http://dx.doi.org/10.1109/INFCOM.2010.5461954},
Abstract = {This paper investigates pricing of Internet connectivity
services in the context of a monopoly ISP selling broadband
access to consumers. We first study the optimal combination
of flat-rate and usage-based access price components for
maximization of ISP revenue, subject to a capacity
constraint on the datarate demand. Next, we consider
time-varying consumer utilities for broadband data rates
that can result in uneven demand for data-rate over time.
Practical considerations limit the viability of altering
prices over time to smoothen out the demanded datarate.
Despite such constraints on pricing, our analysis reveals
that the ISP can retain the revenue by setting a low usage
fee and dropping packets of consumer demanded data that
exceed capacity. Regulatory attention on ISP congestion
management discourages such "technical" practices and
promotes economics based approaches. We characterize the
loss in ISP revenue from an economics based approach.
Regulatory requirements further impose limitations on price
discrimination across consumers, and we derive the revenue
loss to the ISP from such restrictions. We then develop
partial recovery of revenue loss through non-linear pricing
that does not explicitly discriminate across consumers.
While determination of the access price is ultimately based
on additional considerations beyond the scope of this paper,
the analysis here can serve as a benchmark to structure
access price in broadband access networks. ©2010
IEEE.},
Doi = {10.1109/INFCOM.2010.5461954},
Key = {fds235953}
}

@article{fds235954,
Author = {Raginsky, M and Jafarpour, S and Willett, R and Calderbank,
R},
Title = {Fishing in poisson streams: Focusing on the whales, ignoring
the minnows},
Journal = {2010 44th Annual Conference on Information Sciences and
Systems, CISS 2010},
Year = {2010},
url = {http://dx.doi.org/10.1109/CISS.2010.5464841},
Abstract = {This paper describes a low-complexity approach for
reconstructing average packet arrival rates and
instantaneous packet counts at a router in a communication
network, where the arrivals of packets in each flow follow a
Poisson process. Assuming that the rate vector of this
Poisson process is sparse or approximately sparse, the goal
is to maintain a compressed summary of the process sample
paths using a small number of counters, such that at any
time it is possible to reconstruct both the total number of
packets in each flow and the underlying rate vector. We show
that these tasks can be accomplished efficiently and
accurately using compressed sensing with expander graphs. In
particular, the compressive counts are a linear
transformation of the underlying counting process by the
adjacency matrix of an unbalanced expander. Such a matrix is
binary and sparse, which allows for efficient incrementing
when new packets arrive. We describe, analyze, and compare
two methods that can be used to estimate both the current
vector of total packet counts and the underlying vector of
arrival rates. ©2010 IEEE.},
Doi = {10.1109/CISS.2010.5464841},
Key = {fds235954}
}

@article{fds235955,
Author = {Chi, Y and Wu, Y and Calderbank, R},
Title = {Regularized blind detection for MIMO communications},
Journal = {IEEE International Symposium on Information Theory -
Proceedings},
Pages = {2108-2112},
Year = {2010},
url = {http://dx.doi.org/10.1109/ISIT.2010.5513407},
Abstract = {Multiple-Input Multiple-Output (MIMO) systems improve the
throughput and reliability of wireless communications.
Perfect Channel State Information (CSI) is needed at the
receiver to perform coherent detection and achieve the
optimal gain of the system. In fast fading and low SNR
regimes, it is hard or impossible to obtain perfect CSI,
which leads the receiver to operate without knowledge of the
CSI and perform blind detection. In reality CSI may be
available to the receiver but this CSI may be insufficient
to support coherent detection. In this paper, we fill the
gap between coherent and blind detection by considering a
more realistic model where the receiver knows the statistics
of the channel, that is Channel Distribution Information
(CDI). We propose a new detection algorithm, called
Regularized Blind Detection (RBD), where coherent and blind
detection can be viewed as special cases in our model. The
algorithm estimates CDI from any training symbols that are
available and maximizes performance given the estimated CDI.
Simulations demonstrate significant improvement in
performance over blind detection. Our work can be viewed as
a systematic exploration of space between coherent and blind
detection with a strong Bayesian statistic flavor. © 2010
IEEE.},
Doi = {10.1109/ISIT.2010.5513407},
Key = {fds235955}
}

@article{fds235956,
Author = {Bajwa, WU and Calderbank, R and Jafarpour, S},
Title = {Model selection: Two fundamental measures of coherence and
their algorithmic significance},
Journal = {IEEE International Symposium on Information Theory -
Proceedings},
Pages = {1568-1572},
Year = {2010},
url = {http://dx.doi.org/10.1109/ISIT.2010.5513474},
Abstract = {The problem of model selection arises in a number of
contexts, such as compressed sensing, subset selection in
linear regression, estimation of structures in graphical
models, and signal denoising. This paper generalizes the
notion of incoherence in the existing literature on model
selection and introduces two fundamental measures of
coherence - termed as the worst-case coherence and the
average coherence - among the columns of a design matrix. In
particular, it utilizes these two measures of coherence to
provide an in-depth analysis of a simple one-step
thresholding (OST) algorithm for model selection. One of the
key insights offered by the ensuing analysis is that OST is
feasible for model selection as long as the design matrix
obeys an easily verifiable property. In addition, the paper
also characterizes the model-selection performance of OST in
terms of the worst-case coherence, μ, and establishes that
OST performs near-optimally in the low signal-to-noise ratio
regime for N × C design matrices with μ ≈ O(N-1/2).
Finally, in contrast to some of the existing literature on
model selection, the analysis in the paper is nonasymptotic
in nature, it does not require knowledge of the true model
order, it is applicable to generic (random or deterministic)
design matrices, and it neither requires submatrices of the
design matrix to have full rank, nor does it assume a
statistical prior on the values of the nonzero entries of
the data vector. © 2010 IEEE.},
Doi = {10.1109/ISIT.2010.5513474},
Key = {fds235956}
}

@article{fds235957,
Author = {Goel, S and Aggarwal, V and Yener, A and Calderbank,
AR},
Title = {Modeling location uncertainty for eavesdroppers: A secrecy
graph approach},
Journal = {IEEE International Symposium on Information Theory -
Proceedings},
Pages = {2627-2631},
Year = {2010},
url = {http://dx.doi.org/10.1109/ISIT.2010.5513702},
Abstract = {In this paper, we consider end-to-end secure communication
in a large wireless network, where the locations of
eavesdroppers are uncertain. Our framework attempts to
bridge the gap between physical layer security under
uncertain channel state information of the eavesdropper and
network level connectivity under security constraints, by
modeling location uncertainty directly at the network level
as correlated node and link failures in a secrecy graph.
Bounds on the percolation threshold are obtained for square
and triangular lattices, and bounds on mean degree are
obtained for Poisson secrecy graphs. Both analytic and
simulation results show the dramatic effect of uncertainty
in location of eavesdroppers on connectivity in a secrecy
graph. © 2010 IEEE.},
Doi = {10.1109/ISIT.2010.5513702},
Key = {fds235957}
}

@article{fds235958,
Author = {Chiang, M and Hande, P and Kim, H and Ha, S and Calderbank,
R},
Title = {Pricing broadband: Survey and open problems},
Journal = {ICUFN 2010 - 2nd International Conference on Ubiquitous and
Future Networks},
Pages = {303-308},
Year = {2010},
url = {http://dx.doi.org/10.1109/ICUFN.2010.5547185},
Abstract = {Driven by the emerging directions from the FCC and the
broadband market, this paper aims at answering the
fundamental question of how to use pricing as a lever to
enable universal broadband coverage and effective network
management in the United States. We address differential
pricing as a network management tool, i.e., what to charge,
how to charge, and how much to charge. We also outline
research towards multi-platform two-sided pricing focusing
on ISP that charges both content and application providers.
Open problems are highlghted. As a next step, through
collaboration we will combine the access to large-scale
empirical data with rigorous modeling and analysis; we will
go all the way from data collection through mathematical
analysis to practical impact on policy decisions and ISP
business decisions, thus closing the loop in the study of
network economics for universal broadband coverage. © 2010
IEEE.},
Doi = {10.1109/ICUFN.2010.5547185},
Key = {fds235958}
}

@article{fds235959,
Author = {Chi, Y and Pezeshki, A and Scharf, L and Calderbank,
R},
Title = {Sensitivity to basis mismatch in compressed
sensing},
Journal = {IEEE International Conference on Acoustics Speech and Signal
Processing},
Pages = {3930-3933},
Year = {2010},
ISSN = {1520-6149},
url = {http://dx.doi.org/10.1109/ICASSP.2010.5495800},
Abstract = {Compressed sensing theory suggests that successful inversion
of an image of the physical world from its modal parameters
can be achieved at measurement dimensions far lower than the
image dimension, provided that the image is sparse in an a
priori known basis. The assumed basis for sparsity typically
corresponds to a gridding of the parameter space, e.g., an
DFT grid in spectrum analysis. However, in reality no
physical field is sparse in the DFT basis or in an a priori
known basis. No matter how finely we grid the parameter
space the sources may not lie in the center of the grid
cells and there is always mismatch between the assumed and
the actual bases for sparsity. In this paper, we study the
sensitivity of compressed sensing (basis pursuit to be
exact) to mismatch between the assumed and the actual
sparsity bases. Our mathematical analysis and numerical
examples show that the performance of basis pursuit degrades
considerably in the presence of basis mismatch. ©2010
IEEE.},
Doi = {10.1109/ICASSP.2010.5495800},
Key = {fds235959}
}

@article{fds235960,
Author = {Calderbank, R and Howard, S and Jafarpour, S},
Title = {Sparse reconstruction via the reed-muller
sieve},
Journal = {IEEE International Symposium on Information Theory -
Proceedings},
Pages = {1973-1977},
Year = {2010},
url = {http://dx.doi.org/10.1109/ISIT.2010.5513361},
Abstract = {This paper introduces the Reed Muller Sieve, a deterministic
measurement matrix for compressed sensing. The columns of
this matrix are obtained by exponentiating codewords in the
quaternary second order Reed Muller code of length N. For k
= O(N), the Reed Muller Sieve improves upon prior methods
for identifying the support of a k-sparse vector by removing
the requirement that the signal entries be independent. The
Sieve also enables local detection; an algorithm is
presented with complexity N2 log N that detects the presence
or absence of a signal at any given position in the data
domain without explicitly reconstructing the entire signal.
Reconstruction is shown to be resilient to noise in both the
measurement and data domains; the ℓ2/ℓ2 error bounds
derived in this paper are tighter than the ℓ2/ℓ1 bounds
arising from random ensembles and the ℓ1/ℓ1 bounds
arising from expander-based ensembles. © 2010
IEEE.},
Doi = {10.1109/ISIT.2010.5513361},
Key = {fds235960}
}

@article{fds235961,
Author = {Qureshi, TR and Zoltowski, MD and Calderbank, R},
Title = {Target detection in mimo radar in the presence of doppler
using complementary sequences},
Journal = {IEEE International Conference on Acoustics Speech and Signal
Processing},
Pages = {2766-2769},
Year = {2010},
ISSN = {1520-6149},
url = {http://dx.doi.org/10.1109/ICASSP.2010.5496206},
Abstract = {In this paper, we present a method for detecting a point
target using multiple antennas when the relative motion
between the receivers and the target induces a
non-negligible Doppler shift. As a key illustrative example,
we consider a 4x4 system employing a unitary matrix waveform
set, e.g., formed from Golay complementary sequences. When a
non-negligible Doppler shift is induced by the target
motion, the waveform matrix formed from the complementary
sequences is no longer unitary, resulting in significantly
degraded target range estimates. To solve this problem, we
adopt a subspace based approach exploiting the observation
that the receive matrix formed from matched filtering of the
reflected waveforms has a (non-trivial) null-space. Through
processing of the waveforms with the appropriate vector from
the null-space, we can significantly improve the detection
performance. We provide simulation results to confirm the
theoretical analysis. ©2010 IEEE.},
Doi = {10.1109/ICASSP.2010.5496206},
Key = {fds235961}
}

@article{fds235962,
Author = {Wu, Y and Calderbank, R},
Title = {Circulant space-time codes for integration with
beamforming},
Journal = {IEEE International Conference on Acoustics Speech and Signal
Processing},
Pages = {2550-2553},
Year = {2010},
ISSN = {1520-6149},
url = {http://dx.doi.org/10.1109/ICASSP.2010.5496288},
Abstract = {This paper provides a framework for designing space-time
codes to take advantage of a small number of feedback bits
from the receiver. The new codes are based on circulant
matrices and simple conditions are derived that guarantee
full rate and full diversity. In the absence of feedback,
Symbol Error Rate (SER) performance is shown to be similar
to that of Diagonal Algebraic Space-Time (DAST) codes, both
for Maximum Likelihood (ML) decoding and for suboptimal
linear decoding. Decoding complexity of circulant codes is
similar to the DAST codes and encoding is slightly less
complex. In the presence of a small number of feedback bits
from the receiver the circulant construction is shown to
permit integration of space-time coding with a fixed set of
beams by simply advancing the phase on one of the antennas.
This integration is not possible within the DAST framework.
Integration of space-time codes with beamforming makes it
possible to achieve ML decoding performance with only linear
decoding complexity or to improve upon ML performance of the
original code. ©2010 IEEE.},
Doi = {10.1109/ICASSP.2010.5496288},
Key = {fds235962}
}

@article{fds235963,
Author = {Wu, Y and Chi, Y and Calderbank, R},
Title = {Compressive blind source separation},
Journal = {Proceedings / ICIP ... International Conference on Image
Processing},
Pages = {89-92},
Year = {2010},
ISSN = {1522-4880},
url = {http://dx.doi.org/10.1109/ICIP.2010.5652624},
Abstract = {The central goal of compressive sensing is to reconstruct a
signal that is sparse or compressible in some basis using
very few measurements. However reconstruction is often not
the ultimate goal and it is of considerable interest to be
able to deduce attributes of the signal from the
measurements without explicitly reconstructing the full
signal. This paper solves the blind source separation
problem not in the high dimensional data domain, but in the
low dimensional measurement domain. It develops a Bayesian
inference framework that integrates hidden Markov models for
sources with compressive measurement. Posterior
probabilities are calculated using a Markov Chain Monte
Carlo (MCMC) algorithm. Simulation results are provided for
one-dimensional signals and for two-dimensional images,
where hidden Markov tree models of the wavelet coefficients
are considered. The integrated Bayesian framework is shown
to outperform standard approaches where the mixtures are
separated in the data domain. © 2010 IEEE.},
Doi = {10.1109/ICIP.2010.5652624},
Key = {fds235963}
}

@article{fds235964,
Author = {Calderbank, R and Jafarpour, S},
Title = {Reed Muller sensing matrices and the LASSO (Invited
paper)},
Journal = {Lecture notes in computer science},
Volume = {6338 LNCS},
Pages = {442-463},
Year = {2010},
ISSN = {0302-9743},
url = {http://dx.doi.org/10.1007/978-3-642-15874-2_37},
Abstract = {We construct two families of deterministic sensing matrices
where the columns are obtained by exponentiating codewords
in the quaternary Delsarte-Goethals code DG(m,r). This
method of construction results in sensing matrices with low
coherence and spectral norm. The first family, which we call
Delsarte-Goethals frames, are 2m - dimensional tight frames
with redundancy 2rm . The second family, which we call
Delsarte-Goethals sieves, are obtained by subsampling the
column vectors in a Delsarte-Goethals frame. Different rows
of a Delsarte-Goethals sieve may not be orthogonal, and we
present an effective algorithm for identifying all pairs of
non-orthogonal rows. The pairs turn out to be duplicate
measurements and eliminating them leads to a tight frame.
Experimental results suggest that all DG(m,r) sieves with m
≤ 15 and r ≥ 2 are tight-frames; there are no duplicate
rows. For both families of sensing matrices, we measure
accuracy of reconstruction (statistical 0 - 1 loss) and
complexity (average reconstruction time) as a function of
the sparsity level k. Our results show that DG frames and
sieves outperform random Gaussian matrices in terms of
noiseless and noisy signal recovery using the LASSO. © 2010
Springer-Verlag.},
Doi = {10.1007/978-3-642-15874-2_37},
Key = {fds235964}
}

@article{fds235965,
Author = {Wu, Y and Achtzehn, A and Petrova, M and Mähönen, P and Calderbank,
R},
Title = {On the effect of feedback delay on limited-rate beamforming
systems},
Journal = {GLOBECOM - IEEE Global Telecommunications
Conference},
Year = {2010},
url = {http://dx.doi.org/10.1109/GLOCOM.2010.5684288},
Abstract = {The use of beamforming to enable higher data rates in
telecommunications is widely appreciated, but performance
gains are typically calculated assuming delay-free feedback
from the receiver and neglecting processing time. This paper
introduces a mathematical framework based on outage
probability that measures the extent to which current
channel state information is accurate. Performance gains
from beamforming can then be evaluated as a function of the
currency of system state. Results are provided for Multiple
Input Single Output (MISO) and for Multiuser Multiple Input
Multiple Output (MU-MIMO) systems. Outage probabilities and
effective diversity orders are calculated for widely used
methods of beamforming such as Transmit Antenna Selection as
a function of the speed of channel variation. ©2010
IEEE.},
Doi = {10.1109/GLOCOM.2010.5684288},
Key = {fds235965}
}

@article{fds235966,
Author = {Bajwa, WU and Calderbank, R and Jafarpour, S},
Title = {Revisiting model selection and recovery of sparse signals
using one-step thresholding},
Journal = {2010 48th Annual Allerton Conference on Communication,
Control, and Computing, Allerton 2010},
Pages = {977-984},
Year = {2010},
url = {http://dx.doi.org/10.1109/ALLERTON.2010.5707015},
Abstract = {This paper studies non-asymptotic model selection and
recovery of sparse signals in high-dimensional, linear
inference problems. In contrast to the existing literature,
the focus here is on the general case of arbitrary design
matrices and arbitrary nonzero entries of the signal. In
this regard, it utilizes two easily computable measures of
coherence - termed as the worstcase coherence and the
average coherence - among the columns of a design matrix to
analyze a simple, model-order agnostic one-step thresholding
(OST) algorithm. In particular, the paper establishes that
if the design matrix has reasonably small worst-case and
average coherence then OST performs near-optimal model
selection when either (i) the energy of any nonzero entry of
the signal is close to the average signal energy per nonzero
entry or (ii) the signal-to-noise ratio (SNR) in the
measurement system is not too high. Further, the paper shows
that if the design matrix in addition has sufficiently small
spectral norm then OST also exactly recovers most sparse
signals whose nonzero entries have approximately the same
magnitude even if the number of nonzero entries scales
almost linearly with the number of rows of the design
matrix. Finally, the paper also presents various classes of
random and deterministic design matrices that can be used
together with OST to successfully carry out near-optimal
model selection and recovery of sparse signals under certain
SNR regimes or for certain classes of signals. ©2010
IEEE.},
Doi = {10.1109/ALLERTON.2010.5707015},
Key = {fds235966}
}

@article{fds235967,
Author = {Applebaum, L and Bajwa, WU and Duarte, MF and Calderbank,
R},
Title = {Multiuser detection in asynchronous on-off random access
channels using lasso},
Journal = {2010 48th Annual Allerton Conference on Communication,
Control, and Computing, Allerton 2010},
Pages = {130-137},
Year = {2010},
url = {http://dx.doi.org/10.1109/ALLERTON.2010.5706898},
Abstract = {This paper considers on-off random access channels where
users transmit either a one or a zero to a base station.
Such channels represent an abstraction of control channels
used for scheduling requests in third-generation cellular
systems and uplinks in wireless sensor networks deployed for
target detection. This paper introduces a novel
convex-optimization-based scheme for multiuser detection
(MUD) in asynchronous on-off random access channels that
does not require knowledge of the delays or the
instantaneous received signal-to-noise ratios of the
individual users at the base station. For any fixed number
of temporal signal space dimensions N and maximum delay τ
in the system, the proposed scheme can accommodate M ≲
exp(O(N1/3)) total users and k ≲ N/log M active users in
the system-a significant improvement over the k ≤ M ≲ N
scaling suggested by the use of classical matched-filtering-
based approaches to MUD employing orthogonal signaling.
Furthermore, the computational complexity of the proposed
scheme differs from that of a similar oracle-based scheme
with perfect knowledge of the user delays by at most a
factor of log(N+τ). Finally, the results presented in here
are non-asymptotic, in contrast to related previous work for
synchronous channels that only guarantees that the
probability of MUD error at the base station goes to zero
asymptotically in M. ©2010 IEEE.},
Doi = {10.1109/ALLERTON.2010.5706898},
Key = {fds235967}
}

@article{fds235968,
Author = {Lau, CC and Calderbank, R and Zoltowski, MD},
Title = {Space-time processing for MIMO-OFDM using DFT-based
complementary sequences},
Journal = {Proceedings of SPIE - The International Society for Optical
Engineering},
Volume = {7706},
Year = {2010},
ISSN = {0277-786X},
url = {http://dx.doi.org/10.1117/12.851020},
Abstract = {In this paper, a new space-time signaling scheme is proposed
for Orthogonal Frequency Division Multiplexing (OFDM) using
complementary sequences derived from the rows of the DFT
matrix. The autocorrelative properties of the complementary
sequences allows multiple complex data signals at the
transmitter with an arbitrary number of antennas to be
perfectly separated and reconstructed at the receiver
without prior channel knowledge while achieving full-rate.
This new method is proposed and derived for multiple
MIMO-OFDM systems with multipath fading; at the receiver,
symbol estimation is effected via maximum likelihood
estimation (ML). © 2010 SPIE.},
Doi = {10.1117/12.851020},
Key = {fds235968}
}

@article{fds235969,
Author = {Nastasescu, MM and Calderbank, AR},
Title = {The projective Kerdock code},
Journal = {2010 IEEE Information Theory Workshop, ITW 2010 -
Proceedings},
Year = {2010},
url = {http://dx.doi.org/10.1109/CIG.2010.5592761},
Abstract = {Certain nonlinear binary codes can be constructed as binary
images of Z4-linear codes under the Gray map. Examples
include the second-order Reed-Muller code and the Kerdock
and Preparata codes. In this paper, we consider a new
quaternary code which is an additive subcode of the Z
4-linear Kerdock code. The Kerdock code is the direct sum of
a one-dimensional quaternary code and the quaternary subcode
examined in this paper. This paper calculates the weight
distribution of the projective Kerdock code from which the
weight distribution of the dual code can be computed. The
dual code is a supercode of the quaternary Preparata code.
The projective Kerdock code is used to construct a
deterministic measurement matrix for compressed sensing.
Numerical experiments are presented for sparse
reconstruction using the LASSO that show improvement over
random Gaussian matrices of the same size. © 2010
IEEE.},
Doi = {10.1109/CIG.2010.5592761},
Key = {fds235969}
}

@article{fds235970,
Author = {Singh, A and Nowak, R and Calderbank, R},
Title = {Detecting weak but hierarchically-structured patterns in
networks},
Journal = {Journal of machine learning research : JMLR},
Volume = {9},
Pages = {749-756},
Year = {2010},
ISSN = {1532-4435},
Abstract = {The ability to detect weak distributed activation patterns
in networks is critical to several applications, such as
identifying the onset of anomalous activity or incipient
congestion in the Internet, or faint traces of a biochemical
spread by a sensor network. This is a challenging problem
since weak distributed patterns can be invisible in per node
statistics as well as a global network-wide aggregate. Most
prior work considers situations in which the
activation/non-activation of each node is statistically
independent, but this is unrealistic in many problems. In
this paper, we consider structured patterns arising from
statistical dependencies in the activation process. Our
contributions are three-fold. First, we propose a
sparsifying transform that succinctly represents structured
activation patterns that conform to a hierarchical
dependency graph. Second, we establish that the proposed
transform facilitates detection of very weak activation
patterns that cannot be detected with existing methods.
Third, we show that the structure of the hierarchical
dependency graph governing the activation process, and hence
the network transform, can be learnt from very few
(logarithmic in network size) independent snapshots of
network activity. Copyright 2010 by the authors.},
Key = {fds235970}
}

@article{fds235971,
Author = {Sirianunpiboon, S and Wu, Y and Calderbank, AR and Howard,
SD},
Title = {Fast optimal decoding of multiplexed orthogonal designs by
conditional optimization},
Journal = {IEEE Transactions on Information Theory},
Volume = {56},
Number = {3},
Pages = {1106-1113},
Year = {2010},
ISSN = {0018-9448},
url = {http://dx.doi.org/10.1109/TIT.2009.2039069},
Abstract = {This paper focuses on conditional optimization as a decoding
primitive for high rate spacetime codes that are obtained by
multiplexing in the spatial and code domains. The approach
is a crystallization of the work of Hottinen which applies
to spacetime codes that are assisted by quasi-orthogonality.
It is independent of implementation and is more general in
that it can be applied to spacetime codes such as the Golden
Code and perfect spacetime block codes, that are not
assisted by quasi-orthogonality, to derive fast decoders
with essentially maximum likelihood (ML) performance. The
conditions under which conditional optimization leads to
reduced complexity ML decoding are captured in terms of the
induced channel at the receiver. These conditions are then
translated back to the transmission domain leading to codes
that are constructed by multiplexing orthogonal designs. The
methods are applied to several block spacetime codes
obtained by multiplexing Alamouti blocks where it leads to
ML decoding with complexity O(N2) where $N$ is the size of
the underlying QAM signal constellation. A new code is
presented that tests commonly accepted design principles and
for which decoding by conditional optimization is both fast
and ML. The two design principles for perfect spacetime
codes are nonvanishing determinant of pairwise differences
and cubic shaping, and it is cubic shaping that restricts
the possible multiplexing structures. The new code shows
that it is possible to give up on cubic shaping without
compromising code performance or decoding complexity. ©
2006 IEEE.},
Doi = {10.1109/TIT.2009.2039069},
Key = {fds235971}
}

@article{fds235972,
Author = {Calderbank, R and Howard, S and Jafarpour, S},
Title = {Construction of a large class of deterministic sensing
matrices that satisfy a statistical isometry
property},
Journal = {IEEE Journal of Selected Topics in Signal
Processing},
Volume = {4},
Number = {2},
Pages = {358-374},
Year = {2010},
ISSN = {1932-4553},
url = {http://dx.doi.org/10.1109/JSTSP.2010.2043161},
Abstract = {Compressed Sensing aims to capture attributes of κ-sparse
signals using very few measurements. In the standard
compressed sensing paradigm, the N × C measurement matrix
Φ is required to act as a near isometry on the set of all
κ-sparse signals (restricted isometry property or RIP).
Although it is known that certain probabilistic processes
generate N × C matrices that satisfy RIP with high
probability, there is no practical algorithm for verifying
whether a given sensing matrix Φ has this property, crucial
for the feasibility of the standard recovery algorithms. In
contrast, this paper provides simple criteria that guarantee
that a deterministic sensing matrix satisfying these
criteria acts as a near isometry on an overwhelming majority
of κ-sparse signals; in particular, most such signals have
a unique representation in the measurement domain.
Probability still plays a critical role, but it enters the
signal model rather than the construction of the sensing
matrix. An essential element in our construction is that we
require the columns of the sensing matrix to form a group
under pointwise multiplication. The construction allows
recovery methods for which the expected performance is
sub-linear in C, and only quadratic in N, as compared to the
super-linear complexity in C of the Basis Pursuit or
Matching Pursuit algorithms; the focus on expected
performance is more typical of mainstream signal processing
than the worst case analysis that prevails in standard
compressed sensing. Our framework encompasses many families
of deterministic sensing matrices, including those formed
from discrete chirps, DelsarteGoethals codes, and extended
BCH codes. © IEEE.},
Doi = {10.1109/JSTSP.2010.2043161},
Key = {fds235972}
}

@article{fds235973,
Author = {Li, Y and Tian, C and Diggavi, S and Chiang, M and Calderbank,
A},
Title = {Network resource allocation for competing multiple
description transmissions},
Journal = {IEEE Transactions on Communications},
Volume = {58},
Number = {5},
Pages = {1493-1504},
Year = {2010},
ISSN = {0090-6778},
url = {http://dx.doi.org/10.1109/TCOMM.2010.05.080551},
Abstract = {Providing real-time multimedia services over a besteffort
network is challenging due to the stringent delay
requirements in the presence of complex network dynamics.
Multiple description (MD) coding is one approach to transmit
the media over diverse (multiple) paths to reduce the
detrimental effects caused by path failures or delay. The
novelty of this work is to investigate the resource
allocation in a network, where there are several competing
MD coded streams. This is done by considering a framework
that chooses the operating points for asymmetric MD coding
to maximize total quality of the users, while these streams
are sent over multiple routing paths. The framework is based
on the theoretical modeling where we consider two
descriptions and high source coding rate region approximated
within small constants. We study the joint optimization of
multimedia (source) coding and congestion control in wired
networks. These ideas are extended to joint source coding
and channel coding in wireless networks. In both situations,
we propose distributed algorithms for optimal resource
allocation. In the presence of path loss and competing
users, the service quality to any particular MD stream could
be uncertain. In such circumstances it might be tempting to
expect that we need greater redundancy in the MD streams to
protect against such failures. However, one surprising
aspect of our study reveals that for large number of users
who compete for the same resources, the overall system could
benefit through opportunistic (hierarchical) strategies. In
general networks, our studies indicate that the user
composition varies from conservative to opportunistic
operating points, depending on the number of users and their
network vantage points. © 2006 IEEE.},
Doi = {10.1109/TCOMM.2010.05.080551},
Key = {fds235973}
}

@article{fds235974,
Author = {Bajwa, WU and Calderbank, R and Jafarpour, S},
Title = {Why Gabor frames? Two fundamental measures of coherence and
their role in model selection},
Journal = {Journal of Communications and Networks},
Volume = {12},
Number = {4},
Pages = {289-307},
Year = {2010},
ISSN = {1229-2370},
Abstract = {The problem of model selection arises in a number of
contexts, such as subset selection in linear regression,
estimation of structures in graphical models, and signal
denoising. This paper studies non-asymptotic model selection
for the general case of arbitrary (random or deterministic)
design matrices and arbitrary nonzero entries of the signal.
In this regard, it generalizes the notion of incoherence in
the existing literature on model selection and introduces
two fundamental measures of coherence- termed as the
worst-case coherence and the average coherence-among the
columns of a design matrix. It utilizes these two measures
of coherence to provide an in-depth analysis of a simple,
model-order agnostic one-step thresholding (OST) algorithm
for model selection and proves that OST is feasible for
exact as well as partial model selection as long as the
design matrix obeys an easily verifiable property, which is
termed as the coherence property. One of the key insights
offered by the ensuing analysis in this regard is that OST
can successfully carry out model selection even when methods
based on convex optimization such as the lasso fail due to
the rank deficiency of the submatrices of the design matrix.
In addition, the paper establishes that if the design matrix
has reasonably small worst-case and average coherence then
OST performs near-optimally when either (i) the energy of
any nonzero entry of the signal is close to the average
signal energy per nonzero entry or (ii) the signal-to-noise
ratio in the measurement system is not too high. Finally,
two other key contributions of the paper are that (i) it
provides bounds on the average coherence of Gaussian
matrices and Gabor frames, and (ii) it extends the results
on model selection using OST to low-complexity, model-order
agnostic recovery of sparse signals with arbitrary nonzero
entries. In particular, this part of the analysis in the
paper implies that an Alltop Gabor frame together with OST
can successfully carry out model selection and recovery of
sparse signals irrespective of the phases of the nonzero
entries even if the number of nonzero entries scales almost
linearly with the number of rows of the Alltop Gabor frame.
Key = {fds235974}
}

@article{fds235975,
Author = {Aggarwal, V and Calderbank, AR and Gilbert, G and Weinstein,
YS},
Title = {Volume thresholds for quantum fault tolerance},
Journal = {Quantum Information Processing},
Volume = {9},
Number = {5},
Pages = {541-549},
Year = {2010},
ISSN = {1570-0755},
url = {http://dx.doi.org/10.1007/s11128-010-0181-2},
Abstract = {We introduce finite-level concatenation threshold regions
for quantum fault tolerance. These volume thresholds are
regions in an error probability manifold that allow for the
implemented system dynamics to satisfy a prescribed
implementation inaccuracy bound at a given level of quantum
error correction concatenation. Satisfying this condition
constitutes our fundamental definition of fault tolerance.
The prescribed bound provides a halting condition
identifying the attainment of fault tolerance that allows
for the determination of the optimum choice of quantum error
correction code(s) and number of concatenation levels. Our
method is constructed to apply to finite levels of
concatenation, does not require that error proabilities
consistently decrease from one concatenation level to the
next, and allows for analysis, without approximations, of
physical systems characterized by non-equiprobable
distributions of qubit error probabilities. We demonstrate
the utility of this method via a general error model. ©
2010 Springer Science+Business Media, LLC.},
Doi = {10.1007/s11128-010-0181-2},
Key = {fds235975}
}

@article{fds235976,
Author = {Ashikhmin, A and Calderbank, AR},
Title = {Grassmannian packings from operator ReedMuller
codes},
Journal = {IEEE Transactions on Information Theory},
Volume = {56},
Number = {11},
Pages = {5689-5714},
Year = {2010},
ISSN = {0018-9448},
url = {http://dx.doi.org/10.1109/TIT.2010.2070192},
Abstract = {This paper introduces multidimensional generalizations of
binary Reed-Muller codes where the codewords are projection
operators, and the corresponding subspaces are widely
separated with respect to the chordal distance on
Grassmannian space. Parameters of these Grassmannian
packings are derived and a low complexity decoding algorithm
is developed by modifying standard decoding algorithms for
binary Reed-Muller codes. The subspaces are associated with
projection operators determined by Pauli matrices appearing
in the theory of quantum error correction and this
connection with quantum stabilizer codes may be of
independent interest. The Grassmannian packings constructed
here find application in noncoherent wireless communication
with multiple antennas, where separation with respect to the
chordal distance on Grassmannian space guarantees closeness
to the channel capacity. It is shown that the capacity of
the noncoherent multiple-inputmultiple-output (MIMO) channel
at both low and moderate signal-to-noise ratio (SNR) (under
the constraint that only isotropically distributed unitary
matrices are used for information transmission) is closely
approximated by these packings. © 2006 IEEE.},
Doi = {10.1109/TIT.2010.2070192},
Key = {fds235976}
}

@article{fds235977,
Author = {Wolff, J and Martens, M and Jafarpour, S and Daubechies, I and Calderbank, R},
Title = {Uncovering elements of style},
Journal = {IEEE International Conference on Acoustics Speech and Signal
Processing},
Pages = {1017-1020},
Year = {2011},
ISSN = {1520-6149},
url = {http://dx.doi.org/10.1109/ICASSP.2011.5946579},
Abstract = {This paper relates the style of 16th century Flemish
paintings by Goossen van der Weyden (GvdW) to the style of
preliminary sketches or underpaintings made prior to
executing the painting. Van der Weyden made underpaintings
in markedly different styles for reasons as yet not
understood by art historians. The analysis presented here
starts from a classification of the underpaintings into four
distinct styles by experts in art history. Analysis of the
painted surfaces by a combination of wavelet analysis,
hidden Markov trees and boosting algorithms can distinguish
the four underpainting styles with greater than 90%
cross-validation accuracy. On a subsequent blind test this
classifier provided insight into the hypothesis by art
historians that different patches of the finished painting
were executed by different hands. © 2011
IEEE.},
Doi = {10.1109/ICASSP.2011.5946579},
Key = {fds235977}
}

@article{fds235978,
Author = {Goparaju, S and Calderbank, AR and Carson, WR and Rodrigues, MRD and Perez-Cruz, F},
Title = {When to add another dimension when communicating over MIMO
channels},
Journal = {IEEE International Conference on Acoustics Speech and Signal
Processing},
Pages = {3100-3103},
Year = {2011},
ISSN = {1520-6149},
url = {http://dx.doi.org/10.1109/ICASSP.2011.5946351},
Abstract = {This paper introduces a divide and conquer approach to the
design of transmit and receive filters for communication
over a Multiple Input Multiple Output (MIMO) Gaussian
channel subject to an average power constraint. It involves
conversion to a set of parallel scalar channels, possibly
with very different gains, followed by coding per
sub-channel (i.e. over time) rather than coding across
sub-channels (i.e. over time and space). The loss in
performance is negligible at high signal-to-noise ratio
(SNR) and not significant at medium SNR. The advantages are
reduction in signal processing complexity and greater
insight into the SNR thresholds at which a channel is first
allocated power. This insight is a consequence of
formulating the optimal power allocation in terms of an
upper bound on error rate that is determined by parameters
of the input lattice such as the minimum distance and
kissing number. The resulting thresholds are given
explicitly in terms of these lattice parameters. By
contrast, when the optimization problem is phrased in terms
of maximizing mutual information, the solution is mercury
waterfilling, and the thresholds are implicit. © 2011
IEEE.},
Doi = {10.1109/ICASSP.2011.5946351},
Key = {fds235978}
}

@article{fds235979,
Author = {Wu, Y and Zheng, H and Calderbank, R and Kulkarni, S and Poor,
HV},
Title = {On optimal precoding in wireless multicast
systems},
Journal = {IEEE International Conference on Acoustics Speech and Signal
Processing},
Pages = {3068-3071},
Year = {2011},
ISSN = {1520-6149},
url = {http://dx.doi.org/10.1109/ICASSP.2011.5946306},
Abstract = {Precoding has been extensively studied for point-to-point
communications, including the problems of constructing the
precoding codebook and selecting the best precoder. This
paper investigates precoding for a multicast channel in
which a base station is sending the same information to all
users and each user sends back the index of its best
precoding matrix. It is assumed that users do not
collaborate and that no channel state information is known
at the base station. Optimization problems are formulated to
reduce the packet drop rate. A set of probabilistic
algorithms that effectively reduce the average package drop
rate are presented. It is shown numerically that these new
schemes lead to significant improvements. © 2011
IEEE.},
Doi = {10.1109/ICASSP.2011.5946306},
Key = {fds235979}
}

@article{fds235980,
Author = {Kostina, V and Duarte, MF and Jafarpour, S and Calderbank,
R},
Title = {The value of redundant measurement in compressed
sensing},
Journal = {IEEE International Conference on Acoustics Speech and Signal
Processing},
Pages = {3656-3659},
Year = {2011},
ISSN = {1520-6149},
url = {http://dx.doi.org/10.1109/ICASSP.2011.5947143},
Abstract = {The aim of compressed sensing is to recover attributes of
sparse signals using very few measurements. Given an overall
bit budget for quantization, this paper demonstrates that
there is value to redundant measurement. The measurement
matrices considered here are required to have the property
that signal recovery is still possible even after dropping
certain subsets of D measurements. It introduces the concept
of a measurement matrix that is weakly democratic in the
sense that the amount of information about the signal
carried by each of the designated D-subsets is the same.
Examples of deterministic measurement matrices that are
weakly democratic are constructed by exponentiating
codewords from the binary second order Reed Muller code. The
value in rejecting D measurements that are on average
larger, is to be able to provide a finer grid for vector
quantization of the remaining measurements, even after
discounting the original budget by the bits used to identify
the reject set. Simulation results demonstrate that
redundancy improves recovery SNR, sometimes by a wide
margin. Optimum performance occurs when a significant
fraction of measurements are rejected. © 2011
IEEE.},
Doi = {10.1109/ICASSP.2011.5947143},
Key = {fds235980}
}

@article{fds235981,
Author = {Krishnamurthy, K and Bajwa, WU and Willett, R and Calderbank,
R},
Title = {Fast level set estimation from projection
measurements},
Journal = {IEEE Workshop on Statistical Signal Processing
Proceedings},
Pages = {585-588},
Year = {2011},
url = {http://dx.doi.org/10.1109/SSP.2011.5967766},
Abstract = {Estimation of the level set of a function (i.e., regions
where the function exceeds some value) is an important
problem with applications in digital elevation maps, medical
imaging, and astronomy. In many applications, however, the
function of interest is acquired through indirect
measurements, such as tomographic projections,
coded-aperture measurements, or pseudo-random projections
associated with compressed sensing. This paper describes a
new methodology and associated theoretical analysis for
rapid and accurate estimation of the level set from such
projection measurements. The proposed method estimates the
level set from projection measurements without an
intermediate function reconstruction step, thereby leading
to significantly faster computation. In addition, the
coherence of the projection operator and McDiarmid's
inequality are used to characterize the estimator's
performance. © 2011 IEEE.},
Doi = {10.1109/SSP.2011.5967766},
Key = {fds235981}
}

@article{fds235982,
Author = {Harms, A and Bajwa, WU and Calderbank, R},
Title = {Beating Nyquist through correlations: A constrained random
demodulator for sampling of sparse bandlimited
signals},
Journal = {IEEE International Conference on Acoustics Speech and Signal
Processing},
Pages = {5968-5971},
Year = {2011},
ISSN = {1520-6149},
url = {http://dx.doi.org/10.1109/ICASSP.2011.5947721},
Abstract = {Technological constraints severely limit the rate at which
analog-to-digital converters can reliably sample signals.
Recently, Tropp et al. proposed an architecture, termed the
random demodulator (RD), that attempts to overcome this
obstacle for sparse bandlimited signals. One integral
component of the RD architecture is a white noise-like,
bipolar modulating waveform that changes polarity at a rate
equal to the signal bandwidth. Since there is a hardware
limitation to how fast analog waveforms can change polarity
without undergoing shape distortion, this leads to the RD
also having a constraint on the maximum allowable bandwidth.
In this paper, an extension of the RD, termed the
constrained random demodulator (CRD), is proposed that
bypasses this bottleneck by replacing the original
modulating waveform with a run-length limited (RLL)
modulating waveform that changes polarity at a slower rate
than the signal bandwidth. One of the main contributions of
the paper is establishing that the CRD, despite employing a
modulating waveform with correlations, enjoys some
theoretical guarantees for certain RLL waveforms. In
addition, for a given sampling rate and rate of change in
the modulating waveform polarity, numerical simulations
confirm that the CRD, using an appropriate RLL waveform, can
sample a signal with an even wider bandwidth without a
significant loss in performance. © 2011
IEEE.},
Doi = {10.1109/ICASSP.2011.5947721},
Key = {fds235982}
}

@article{fds235983,
Author = {Applebaum, L and Bajwa, WU and Calderbank, AR and Haupt, J and Nowak,
R},
Title = {Deterministic pilot sequences for sparse channel estimation
in OFDM systems},
Journal = {17th DSP 2011 International Conference on Digital Signal
Processing, Proceedings},
Year = {2011},
url = {http://dx.doi.org/10.1109/ICDSP.2011.6005024},
Abstract = {This paper examines the problem of multipath channel
estimation in single-antenna orthogonal frequency division
multiplexing (OFDM) systems. In particular, we study the
problem of pilot assisted channel estimation in wideband
OFDM systems, where the time-domain (discrete) channel is
approximately sparse. Existing works on this topic
established that techniques from the compressed sensing
literature can yield accurate channel estimates using a
relatively small number of pilot tones, provided the pilots
are selected randomly. Here, we describe a general purpose
procedure for deterministic selection of pilot tones to be
used for channel estimation, and establish guarantees for
channel estimation accuracy using these sequences along with
recovery techniques from the compressed sensing literature.
Simulation results are presented to demonstrate the
effectiveness of the proposed procedure in practice. © 2011
IEEE.},
Doi = {10.1109/ICDSP.2011.6005024},
Key = {fds235983}
}

@article{fds235984,
Author = {Mixon, DG and Bajwa, WU and Calderbank, R},
Title = {Frame coherence and sparse signal processing},
Journal = {IEEE International Symposium on Information Theory -
Proceedings},
Pages = {663-667},
Year = {2011},
url = {http://dx.doi.org/10.1109/ISIT.2011.6034214},
Abstract = {The sparse signal processing literature often uses random
sensing matrices to obtain performance guarantees.
Unfortunately, in the real world, sensing matrices do not
always come from random processes. It is therefore desirable
to evaluate whether an arbitrary matrix, or frame, is
suitable for sensing sparse signals. To this end, the
present paper investigates two parameters that measure the
coherence of a frame: worst-case and average coherence. We
first provide several examples of frames that have small
spectral norm, worst-case coherence, and average coherence.
Next, we present a new lower bound on worst-case coherence
and compare it to the Welch bound. Later, we propose an
algorithm that decreases the average coherence of a frame
without changing its spectral norm or worst-case coherence.
Finally, we use worst-case and average coherence, as opposed
to the Restricted Isometry Property, to garner near-optimal
probabilistic guarantees on both sparse signal detection and
reconstruction in the presence of noise. This contrasts with
recent results that only guarantee noiseless signal recovery
from arbitrary frames, and which further assume independence
across the nonzero entries of the signalin a sense,
requiring small average coherence replaces the need for such
an assumption. © 2011 IEEE.},
Doi = {10.1109/ISIT.2011.6034214},
Key = {fds235984}
}

@article{fds235985,
Author = {Calderbank, R and Jafarpour, S and Nastasescu,
M},
Title = {Covering radius and the Restricted Isometry
Property},
Journal = {2011 IEEE Information Theory Workshop, ITW
2011},
Pages = {558-562},
Year = {2011},
url = {http://dx.doi.org/10.1109/ITW.2011.6089564},
Abstract = {The Restricted Isometry Property or RIP introduced by Candes
and Tao requires an n × p dictionary to act as a near
isometry on all k-sparse signals. This paper provides a very
simple condition under which a dictionary Φ (C) obtained by
exponentiating codewords from a binary linear code C
satisfies the RIP with high probability. The method is to
bound the difference between the dictionary Φ(C) and a
second dictionary A generated by a random Bernoulli process
which is known to satisfy the RIP with high probability. The
difference Δ-Φ (C) is controlled by the covering radius of
C, a fundamental parameter that is bounded above by the
number of weights in the dual code C ⊥ (the external
distance of C). The main result complements a more
sophisticated asymptotic analysis by Babadi and Tarokh of
the distribution of eigenvalues of random submatrices of
Φ(C). In this analysis, divergence from the distribution
corresponding to the full Bernoulli matrix depends on a
different fundamental parameter of C, namely the minimum
distance of the dual code C ⊥. © 2011
IEEE.},
Doi = {10.1109/ITW.2011.6089564},
Key = {fds235985}
}

@article{fds235986,
Author = {Gomaa, A and Chi, Y and Al-Dhahir, N and Calderbank,
R},
Title = {On training signal design for multi-user MIMO-OFDM:
Performance analysis and tradeoffs},
Journal = {IEEE VTS ... Vehicular Technology Conference : VTC :
[proceedings]},
Year = {2011},
ISSN = {1550-2252},
url = {http://dx.doi.org/10.1109/VETECF.2011.6092844},
Abstract = {This paper addresses spectrally-efficient multiantenna
multi-carrier uplink transmission scenarios where the users
overlap in time and frequency and are separated using
spatial processing at the base station. The robustness of
the proposed training sequences to residual carrier
frequency offset and phase noise is evaluated analytically.
This analysis reveals an interesting design tradeoff between
the Peak-to-Average Power Ratio of a training sequence and
the increase in channel estimation mean squared error over
the ideal case when these two impairments are not present.
Doi = {10.1109/VETECF.2011.6092844},
Key = {fds235986}
}

@article{fds235987,
Author = {Applebaum, L and Bajwa, WU and Calderbank, R and Howard,
S},
Title = {Choir codes: Coding for full duplex interference
management},
Journal = {2011 49th Annual Allerton Conference on Communication,
Control, and Computing, Allerton 2011},
Pages = {1-8},
Year = {2011},
url = {http://dx.doi.org/10.1109/Allerton.2011.6120141},
Abstract = {Communication networks conventionally operate with
half-duplex methods and interference avoiding schemes to
manage multiple transceivers. Here we consider a method in
which nodes transmit and receive in concert to achieve full
duplex communication without transmitter coordination. We
build on a recent framework for full-duplex communication in
ad-hoc wireless networks recently proposed by Zhang, Luo and
Guo. An individual node in the wireless network either
transmits or it listens to transmissions from other nodes
but it cannot do both at the same time. There might be as
many nodes as there are MAC addresses but we assume that
only a small subset of nodes contribute to the superposition
received at any given node in the network. We develop
deterministic algebraic coding methods that allow
simultaneous communication across the entire network. We
call such codes choir codes. Users are assigned subspaces of
F 2m to define their transmit and listen times. Codewords on
these subspaces are designed and proven to adhere to bounds
on worst-case coherence and the associated matrix spectral
norm. This in turn provides guarantees for multi-user
detection using convex optimization. Further, we show that
matrices for each receiver's listening times can be related
by permutations, thus guaranteeing fairness between
receivers. Compared with earlier work using random codes,
our methods have significant improvements including reduced
decoding/detection error and non-asymptotic results.
Simulation results verify that, as a method to manage
interference, our scheme has significant advantages over
seeking to eliminate or align interference through extensive
exchange of fine-grained channel state information. © 2011
IEEE.},
Doi = {10.1109/Allerton.2011.6120141},
Key = {fds235987}
}

@article{fds235988,
Author = {Nokleby, M and Bajwa, WU and Calderbank, R and Aazhang,
B},
Title = {Gossiping in groups: Distributed averaging over the wireless
medium},
Journal = {2011 49th Annual Allerton Conference on Communication,
Control, and Computing, Allerton 2011},
Pages = {1242-1249},
Year = {2011},
url = {http://dx.doi.org/10.1109/Allerton.2011.6120310},
Abstract = {We present an approach to gossip algorithms tailored to the
practical considerations of wireless communications.
Traditional gossip algorithms operate via the pairwise
exchange of estimates, which fails to capture the broadcast
and superposition nature of the wireless medium. Adapting
the virtual full-duplex framework of Guo and Zhang, we
construct a communications scheme in which each node can
broadcast its estimate to its neighbors while simultaneously
receiving its neighbors' estimates. This full-duplex scheme
gives rise to group gossip, a more flexible family of gossip
algorithms built on multilateral, rather than pairwise,
exchanges. Our approach obviates the need for
orthogonalization or medium access; only local information
and synchronization are necessary. Additionally, group
gossip has better convergence properties than does
randomized gossip. Group gossip permits a tighter bound on
the convergence speed than randomized gossip, and in general
the upper bound on the convergence time is at most one-third
that of randomized gossip. © 2011 IEEE.},
Doi = {10.1109/Allerton.2011.6120310},
Key = {fds235988}
}

@article{fds235989,
Author = {Dang, W and Pezeshki, A and Howard, S and Moran, W and Calderbank,
R},
Title = {Coordinating complementary waveforms for sidelobe
suppression},
Journal = {Conference Record of the Asilomar Conference on Signals,
Systems and Computers},
Pages = {2096-2100},
Year = {2011},
ISSN = {1058-6393},
url = {http://dx.doi.org/10.1109/ACSSC.2011.6190398},
Abstract = {We present a general method for constructing radar transmit
pulse trains and receive filters for which the radar
point-spread function in delay and Doppler, given by the
cross-ambiguity function of the transmit pulse train and the
pulse train used in the receive filter, is essentially free
of range sidelobes inside a Doppler interval around the
zero-Doppler axis. The transmit pulse train is constructed
by coordinating the transmission of a pair of Golay
complementary waveforms across time according to zeros and
ones in a binary sequence P. The pulse train used to filter
the received signal is constructed in a similar way, in
terms of sequencing the Golay waveforms, but each waveform
in the pulse train is weighted by an element from another
sequence Q. We show that a spectrum jointly determined by P
and Q sequences controls the size of the range sidelobes of
the cross-ambiguity function and by properly choosing P and
Q we can clear out the range sidelobes inside a Doppler
interval around the zero-Doppler axis. The joint design of P
and Q enables a tradeoff between the order of the spectral
null for range sidelobe suppression and the signal-to-noise
ratio at the receiver output. We establish this trade-off
and derive a necessary and sufficient condition for the
construction of P and Q sequences that produce a null of a
desired order. © 2011 IEEE.},
Doi = {10.1109/ACSSC.2011.6190398},
Key = {fds235989}
}

@article{fds235990,
Author = {Wu, Y and Viswanathan, H and Klein, T and Haner, M and Calderbank,
R},
Title = {Capacity optimization in networks with heterogeneous radio
access technologies},
Journal = {GLOBECOM - IEEE Global Telecommunications
Conference},
Year = {2011},
url = {http://dx.doi.org/10.1109/GLOCOM.2011.6134226},
Abstract = {As it becomes common for wireless service providers (WSP) to
employ multiple heterogeneous radio access technologies
(RAT), the management of the combined resources across
multiple RATs arises as an important issue. The WSP's
objective is to assign different users to the different RATs
so as to maximize network capacity (or total utility) while
ensuring that individual users' quality of service (QoS)
requirements are met. In this paper, we consider this
resource allocation problem for two scenarios: voice
communication and video communication. For voice
communication, we propose a stable and optimal assignment
scheme based on the deferred acceptance algorithm for both
static and online cases. For video communication,
identifying the NP-hardness of the problem, we propose and
compare a set of heuristic algorithms including a
low-complexity, high-performance scheme. © 2011
IEEE.},
Doi = {10.1109/GLOCOM.2011.6134226},
Key = {fds235990}
}

@article{fds235991,
Author = {Li, Y and Papachristodoulou, A and Chiang, M and Calderbank,
AR},
Title = {Congestion control and its stability in networks with delay
sensitive traffic},
Journal = {Computer Networks},
Volume = {55},
Number = {1},
Pages = {20-32},
Year = {2011},
ISSN = {1389-1286},
url = {http://dx.doi.org/10.1016/j.comnet.2010.07.001},
Abstract = {We consider congestion control in a network with delay
sensitive/ insensitive traffic, modelled by adding explicit
delay terms to the utility function measuring user's
happiness on the Quality of Service (QoS). A new Network
Utility Maximization (NUM) problem is formulated and solved
in a decentralized way via appropriate algorithms
implemented at the users (primal) and/or links (dual). For
the dual algorithm, delay-independent and delay-dependent
stability conditions are derived when propagation delays are
taken into account. A system with voice and data traffic is
considered as example and the properties of the congestion
control algorithm are assessed. © 2010 Elsevier B.V. All
rights reserved.},
Doi = {10.1016/j.comnet.2010.07.001},
Key = {fds235991}
}

@article{fds235992,
Author = {Chi, Y and Gomaa, A and Al-Dhahir, N and Calderbank,
R},
Title = {MMSE-optimal training sequences for spectrally-efficient
Multi-User MIMO-OFDM systems},
Journal = {European Signal Processing Conference},
Pages = {634-638},
Year = {2011},
ISSN = {2219-5491},
Abstract = {This paper proposes a new family of optimal training
sequences in terms of minimizing the mean-square channel
estimation error for spectrally-efficient Multi-User
MIMO-OFDM systems with an arbitrary number of transmit
antennas and an arbitrary number of training symbols. It
addresses uplink transmission scenarios where the users
overlap in time and frequency and are separated using
spatial processing at the base station. In particular,
optimal training sequences can be obtained easily from
standard signal constellations such as QPSK with desired low
PAPR, making it appealing for practical use. © 2011
EURASIP.},
Key = {fds235992}
}

@article{fds235993,
Author = {Sirinaunpiboon, S and Calderbank, AR and Howard,
SD},
Title = {Fast essentially maximum likelihood decoding of the Golden
code},
Journal = {IEEE Transactions on Information Theory},
Volume = {57},
Number = {6},
Pages = {3537-3541},
Year = {2011},
ISSN = {0018-9448},
url = {http://dx.doi.org/10.1109/TIT.2011.2136870},
Abstract = {The Golden code is a full-rate full-diversity space-time
code which has been incorporated in the IEEE 802.16 (WiMAX)
standard. The worst case complexity of a tree-based sphere
decoder for a square QAM constellation is O(N 3), where n is
the size of the underlying QAM constellation; the worst case
will dominate average decoding complexity on any channel
with a significant line of sight component. In this paper,
we present a simple algorithm with quadratic complexity for
decoding the Golden code that can be employed by mobile
terminals with either one or two receive antennas, that is
resilient to near singularity of the channel matrix, and
that gives essentially maximum likelihood (ML) performance.
Dual use is an advantage, since there will likely be some
IEEE 802.16 mobile terminals with one receive antenna and
some with two antennas. The key to the quadratic algorithm
is a maximization of the likelihood function with respect to
one of the pair of signal points conditioned on the other.
This choice is made by comparing the determinants of two
covariance matrices, and the underlying geometry of the
Golden code guarantees that one of these choices is good
with high probability. © 2011 IEEE.},
Doi = {10.1109/TIT.2011.2136870},
Key = {fds235993}
}

@article{fds235994,
Author = {Chi, Y and Scharf, LL and Pezeshki, A and Calderbank,
AR},
Title = {Sensitivity to basis mismatch in compressed
sensing},
Journal = {IEEE Transactions on Signal Processing},
Volume = {59},
Number = {5},
Pages = {2182-2195},
Year = {2011},
ISSN = {1053-587X},
url = {http://dx.doi.org/10.1109/TSP.2011.2112650},
Abstract = {The theory of compressed sensing suggests that successful
inversion of an image of the physical world (broadly defined
to include speech signals, radar/sonar returns, vibration
records, sensor array snapshot vectors, 2-D images, and so
on) for its source modes and amplitudes can be achieved at
measurement dimensions far lower than what might be expected
from the classical theories of spectrum or modal analysis,
provided that the image is sparse in an apriori known basis.
For imaging problems in spectrum analysis, and passive and
active radar/sonar, this basis is usually taken to be a DFT
basis. However, in reality no physical field is sparse in
the DFT basis or in any apriori known basis. No matter how
finely we grid the parameter space the sources may not lie
in the center of the grid cells and consequently there is
mismatch between the assumed and the actual bases for
sparsity. In this paper, we study the sensitivity of
compressed sensing to mismatch between the assumed and the
actual sparsity bases. We start by analyzing the effect of
basis mismatch on the best k-term approximation error, which
is central to providing exact sparse recovery guarantees. We
establish achievable bounds for the ℓ1 error of the best
k-term approximation and show that these bounds grow
linearly with the image (or grid) dimension and the mismatch
level between the assumed and actual bases for sparsity. We
then derive bounds, with similar growth behavior, for the
basis pursuit ℓ1 recovery error, indicating that the
sparse recovery may suffer large errors in the presence of
basis mismatch. Although, we present our results in the
context of basis pursuit, our analysis applies to any sparse
recovery principle that relies on the accuracy of best
k-term approximations for its performance guarantees. We
particularly highlight the problematic nature of basis
mismatch in Fourier imaging, where spillage from off-grid
DFT components turns a sparse representation into an
incompressible one. We substantiate our mathematical
analysis by numerical examples that demonstrate a
considerable performance degradation for image inversion
from compressed sensing measurements in the presence of
basis mismatch, for problem sizes common to radar and sonar.
Doi = {10.1109/TSP.2011.2112650},
Key = {fds235994}
}

@article{fds235995,
Author = {Thejaswi, PSC and Bennatan, A and Zhang, J and Calderbank, AR and Cochran, D},
Title = {Layered coding for interference channels with partial
transmitter side information},
Journal = {IEEE Transactions on Information Theory},
Volume = {57},
Number = {5},
Pages = {2765-2780},
Year = {2011},
ISSN = {0018-9448},
url = {http://dx.doi.org/10.1109/TIT.2011.2119670},
Abstract = {A two-user interference channel is considered where each
transmitter has access to a part of the information intended
to the other destination. A primary objective is to maximize
the information rates, by exploring the cooperation between
the transmitters for interference mitigation, based on the
partial side information. It is clear that full cooperation
between the transmitters is not possible since each
transmitter has only a part of the side information. With
this insight, several "layered coding" schemes, consisting
of binning and superposition at different stages, are
developed. These schemes are are carefully built on coding
strategies for the classical interference channel and node
cooperation mechanisms. In particular, two layered coding
schemes, which are based on a combination of MIMO broadcast
coding and the HanKobayashi (HK) coding, are thoroughly
studied : The first one, namely layered coding with binning,
makes heavy use of the GelfandPinsker binning and the HK
coding and the second one, namely layered superposition
coding, involves superposition coding over different tiers.
Rate regions corresponding to the proposed schemes are
derived. Then the application of these coding schemes are
illustrated for the Gaussian case and numerical results
corroborate that the proposed layered coding schemes yield
substantial gains at high SNR. © 2011 IEEE.},
Doi = {10.1109/TIT.2011.2119670},
Key = {fds235995}
}

@article{fds235996,
Author = {Calderbank, R and Casazza, PG and Heinecke, A and Kutyniok, G and Pezeshki, A},
Title = {Sparse fusion frames: Existence and construction},
Journal = {Advances in Computational Mathematics},
Volume = {35},
Number = {1},
Pages = {1-31},
Year = {2011},
ISSN = {1019-7168},
url = {http://dx.doi.org/10.1007/s10444-010-9162-3},
Abstract = {Fusion frame theory is an emerging mathematical theory that
provides a natural framework for performing hierarchical
data processing. A fusion frame can be regarded as a
frame-like collection of subspaces in a Hilbert space, and
thereby generalizes the concept of a frame for signal
representation. However, when the signal and/or subspace
dimensions are large, the decomposition of the signal into
its fusion frame measurements through subspace projections
typically requires a large number of additions and
multiplications, and this makes the decomposition
intractable in applications with limited computing budget.
To address this problem, in this paper, we introduce the
notion of a sparse fusion frame, that is, a fusion frame
whose subspaces are generated by orthonormal basis vectors
that are sparse in a 'uniform basis' over all subspaces,
thereby enabling low-complexity fusion frame decompositions.
We study the existence and construction of sparse fusion
frames, but our focus is on developing simple algorithmic
constructions that can easily be adopted in practice to
produce sparse fusion frames with desired (given) operators.
By a desired (or given) operator we simply mean one that has
a desired (or given) set of eigenvalues for the fusion frame
operator. We start by presenting a complete characterization
of Parseval fusion frames in terms of the existence of
special isometries defined on an encompassing Hilbert space.
We then introduce two general methodologies to generate new
fusion frames from existing ones, namely the Spatial
Complement Method and the Naimark Complement Method, and
analyze the relationship between the parameters of the
original and the new fusion frame. We proceed by
establishing existence conditions for 2-sparse fusion frames
for any given fusion frame operator, for which the
eigenvalues are greater than or equal to two. We then
provide an easily implementable algorithm for computing such
2-sparse fusion frames. © 2010 Springer Science+Business
Media, LLC.},
Doi = {10.1007/s10444-010-9162-3},
Key = {fds235996}
}

@article{fds235997,
Author = {Chi, Y and Gomaa, A and Al-Dhahir, N and Calderbank,
AR},
Title = {Training signal design and tradeoffs for
spectrally-efficient multi-user MIMO-OFDM
systems},
Journal = {IEEE Transactions on Wireless Communications},
Volume = {10},
Number = {7},
Pages = {2234-2245},
Year = {2011},
ISSN = {1536-1276},
url = {http://dx.doi.org/10.1109/TWC.2011.042211.101100},
Abstract = {In this paper, we design MMSE-optimal training sequences for
multi-user MIMO-OFDM systems with an arbitrary number of
transmit antennas and an arbitrary number of training
transmission scenarios where the users overlap in time and
frequency and are separated using spatial processing at the
base station. The robustness of the proposed training
sequences to residual carrier frequency offset and phase
noise is evaluated. This analysis reveals an interesting
design tradeoff between the peak-to-average power ratio of a
training sequence and the increase in channel estimation
mean squared error over the ideal case when these two
impairments are not present. © 2011 IEEE.},
Doi = {10.1109/TWC.2011.042211.101100},
Key = {fds235997}
}

@article{fds235998,
Author = {Qureshi, TR and Zoltowski, MD and Calderbank, R and Pezeshki,
A},
Title = {Unitary design of radar waveform diversity
sets},
Journal = {Digital Signal Processing},
Volume = {21},
Number = {5},
Pages = {552-567},
Year = {2011},
ISSN = {1051-2004},
url = {http://dx.doi.org/10.1016/j.dsp.2010.09.006},
Abstract = {In this work, multiple radar waveforms are simultaneously
transmitted, emitted from different antennas. The goal is to
process the returns in such a way that the overall ambiguity
function is a sum of individual ambiguity functions, such
that the sum better approximates the ideal thumbtack shape.
A unitary design for the illustrative 4×4 example
prescribes the scheduling of the waveforms over four
transmit antennas over four PRIs. Further, it dictates how
the matched filtering of the returns over four PRIs is
combined in such a way so as to achieve both perfect
separation (of the superimposed returns) AND perfect
reconstruction. Perfect reconstruction implies that the sum
of the time-autocorrelations associated with each of the
four waveforms is a delta function. The net result of the
processing of four PRIs over four virtual antennas yields 16
cross-correlations all of which ideally exhibit a sharp peak
at the target delay. Conditions for both perfect separation
and perfect reconstruction are developed, and a variety of
waveform sets satisfying both are presented. Doppler
compensation is achieved by a data-dependent weighting of
the different PRI matched-filtered outputs prior to summing.
Simulations are presented verifying the efficacy of the
proposed unitary waveform matrix designs in conjunction with
the proposed Doppler compensation technique. © 2010
Doi = {10.1016/j.dsp.2010.09.006},
Key = {fds235998}
}

@article{fds235999,
Author = {Goel, S and Aggarwal, V and Yener, A and Calderbank,
AR},
Title = {The effect of eavesdroppers on network connectivity: A
secrecy graph approach},
Journal = {IEEE Transactions on Information Forensics and
Security},
Volume = {6},
Number = {3 PART 1},
Pages = {712-724},
Year = {2011},
ISSN = {1556-6013},
url = {http://dx.doi.org/10.1109/TIFS.2011.2148714},
Abstract = {This paper investigates the effect of eavesdroppers on
network connectivity, using a wiretap model and percolation
theory. The wiretap model captures the effect of
eavesdroppers on link security. A link exists between two
nodes only if the secrecy capacity of that link is positive.
Network connectivity is defined in a percolation sense,
i.e., connectivity exists if an infinite connected component
exists in the corresponding secrecy graph. We consider
uncertainty in location of eavesdroppers, which is modeled
directly at the network level as correlated failures in the
secrecy graph. Our approach attempts to bridge the gap
between physical layer security under uncertain channel
state information and network level connectivity under
secrecy constraints. For square and triangular lattice
secrecy graphs, we obtain bounds on the percolation
threshold, which is the critical value of the probability of
occurrence of an eavesdropper, above which network
connectivity does not exist. For Poisson secrecy graphs,
degree distribution and mean value of upper and lower bounds
on node degree are obtained. Further, inner and outer bounds
on the achievable region for network connectivity are
obtained. Both analytic and simulation results show that
uncertainty in location of eavesdroppers has a dramatic
effect on network connectivity in a secrecy graph. © 2011
IEEE.},
Doi = {10.1109/TIFS.2011.2148714},
Key = {fds235999}
}

@article{fds236000,
Author = {Raginsky, M and Jafarpour, S and Harmany, ZT and Marcia, RF and Willett,
RM and Calderbank, R},
Title = {Performance bounds for expander-based compressed sensing in
poisson noise},
Journal = {IEEE Transactions on Signal Processing},
Volume = {59},
Number = {9},
Pages = {4139-4153},
Year = {2011},
ISSN = {1053-587X},
url = {http://dx.doi.org/10.1109/TSP.2011.2157913},
Abstract = {This paper provides performance bounds for compressed
sensing in the presence of Poisson noise using expander
graphs. The Poisson noise model is appropriate for a variety
of applications, including low-light imaging and digital
streaming, where the signal-independent and/or bounded noise
models used in the compressed sensing literature are no
longer applicable. In this paper, we develop a novel sensing
paradigm based on expander graphs and propose a maximum a
posteriori (MAP) algorithm for recovering sparse or
compressible signals from Poisson observations. The geometry
of the expander graphs and the positivity of the
corresponding sensing matrices play a crucial role in
establishing the bounds on the signal reconstruction error
of the proposed algorithm. We support our results with
experimental demonstrations of reconstructing average packet
arrival rates and instantaneous packet counts at a router in
a communication network, where the arrivals of packets in
each flow follow a Poisson process. © 2011
IEEE.},
Doi = {10.1109/TSP.2011.2157913},
Key = {fds236000}
}

@article{fds235768,
Author = {Simpson, MJ and Wilson, JW and Matthews, TE and Duarte, M and Calderbank, R and Warren, WS},
Title = {Imaging the distribution of melanin in human skin lesions
with pump-probe microscopy},
Journal = {Optics InfoBase Conference Papers},
Year = {2011},
Month = {December},
Key = {fds235768}
}

@article{fds235779,
Author = {Nokleby, M and Bajwa, WU and Calderbank, R and Aazhang,
B},
Title = {Toward resource-optimal averaging consensus over the
wireless medium},
Journal = {Conference Record of the Asilomar Conference on Signals,
Systems and Computers},
Pages = {1197-1201},
Year = {2012},
ISSN = {1058-6393},
url = {http://dx.doi.org/10.1109/ACSSC.2012.6489211},
Abstract = {We carry out a comprehensive study of the resource costs of
distributed averaging consensus in wireless sensor networks.
In particular, we consider two metrics appropriate to the
wireless medium: total transmit energy and time-bandwidth
product. Most previous approaches, such as gossip
algorithms, suppose a graphical network, which abstracts
away crucial features of the wireless medium, and measure
resource consumption only in terms of the total number of
transmissions required to achieve consensus. Under a
path-loss dominated protocol interference model, we study
the performance of several popular gossip algorithms,
showing that they are nearly order-optimal with respect to
transmit energy but strictly sub-optimal with respect to
time-bandwidth product. We also propose a new scheme, termed
hierarchical averaging, which is tailored to the wireless
medium, and show that in general this approach is nearly
order-optimal with respect to time-bandwidth product but
strictly sub-optimal with respect to transmit energy. For
the special case of free-space propagation, however, the
proposed hierarchical scheme is approximately order-optimal
with respect to both metrics. © 2012 IEEE.},
Doi = {10.1109/ACSSC.2012.6489211},
Key = {fds235779}
}

@article{fds235780,
Author = {Harms, A and Bajwa, WU and Calderbank, R},
Title = {Rapid sensing of underutilized, wideband spectrum using the
Random Demodulator},
Journal = {Conference Record of the Asilomar Conference on Signals,
Systems and Computers},
Pages = {1940-1944},
Year = {2012},
ISSN = {1058-6393},
url = {http://dx.doi.org/10.1109/ACSSC.2012.6489377},
Abstract = {Efficient spectrum sensing is an important problem given the
large and increasing demand for wireless spectrum and the
need to protect incumbent users. We can more efficiently use
large swaths of underutilized spectrum by designing spectrum
sensors that can quickly, and power-efficiently, find and
opportunistically communicate over unused (or underutilized)
pieces of spectrum, such as television bands. In this paper,
we concentrate on a particular sensing architecture, the
Random Demodulator (RD), and look at two aspects of the
problem. First, we offer fundamental limits on how
efficiently any algorithm can perform the sensing operation
with the RD. Second, we analyze a very simple,
low-complexity algorithm called one-step thresholding that
has been shown to work near-optimally for certain
measurement classes in a low SNR setting or when the
non-zero input coefficients are nearly equal. We rigorously
establish that the RD architecture is well-suited for
near-optimal recovery of the locations of the non-zero
frequency coefficients in similar settings using one-step
thresholding and perform numerical experiments to offer some
confirmation of our results. © 2012 IEEE.},
Doi = {10.1109/ACSSC.2012.6489377},
Key = {fds235780}
}

@article{fds235781,
Author = {Jacobvitz, AN and Calderbank, R and Sorin, DJ},
Title = {Writing cosets of a convolutional code to increase the
Lifetime of Flash memory},
Journal = {2012 50th Annual Allerton Conference on Communication,
Control, and Computing, Allerton 2012},
Pages = {308-318},
Year = {2012},
url = {http://dx.doi.org/10.1109/Allerton.2012.6483234},
Abstract = {The goal of this paper is to extend the lifetime of Flash
memory by reducing the frequency with which a given page of
memory is erased. This is accomplished by increasing the
number of writes that are possible before erasure is
necessary. Redundancy is introduced into the write process
to decrease the number of memory cells that are impacted by
a given write, and to even out the impact of writing across
an entire page of memory. Improvements are expressed in
terms of write efficiency and lifetime gain. Write
efficiency is the ratio of cells written to cells available,
and lifetime gain is the ratio of coded writes to the
baseline of uncoded writing. We use a physical model that
allows multiple writes to a given region of memory. This can
be realized with single level cells or with multi-level
cells. Data is written to memory in the form of a coset of a
convolutional code. The coset is represented by a binary
vector that is selected by the Viterbi algorithm to minimize
the number of cells impacted by the write (Hamming weight)
and to even out the number of writes to each cell within a
given page. Several different Viterbi metrics are evaluated.
It is shown that page write efficiencies of over 85% and
lifetime gains of over 500% are possible with only modest
encoding and decoding complexity. It is also straightforward
to integrate lifetime extension with standard methods of
error correction by requiring that the coset representative
be drawn from an error correcting code. An example is
provided where single error correction is provided using a
Hamming code. © 2012 IEEE.},
Doi = {10.1109/Allerton.2012.6483234},
Key = {fds235781}
}

@article{fds235783,
Author = {Wu, Y and Jia, T and Calderbank, R and Duel-Hallen, A and Hallen,
H},
Title = {Enabling code diversity for mobile radio channels using
Journal = {IEEE Transactions on Wireless Communications},
Volume = {11},
Number = {12},
Pages = {4362-4371},
Year = {2012},
ISSN = {1536-1276},
url = {http://dx.doi.org/10.1109/TWC.2012.101712.111884},
Abstract = {Code diversity integrates space-time coding with beamforming
by using a small number of feedback bits to select from a
family of space-time codes. Different codes lead to
different induced channels at the receiver, where Channel
State Information (CSI) is used to instruct the transmitter
how to choose the code. Feedback can be combined with
sub-optimal low complexity decoding of the component codes
to match Maximum-Likelihood (ML) decoding performance of any
individual code in the family. It can also be combined with
ML decoding of the component codes to improve performance
beyond ML decoding performance of any individual code. Prior
analysis of code diversity did not take into account the
effect of the mobile speed and the delay in the feedback
channel. This paper demonstrates the practicality of code
diversity in space-time coded systems by showing that
performance gains based on instantaneous feedback are
largely preserved when long-range prediction of time-varying
correlated fading channels is employed to compensate for the
effect of the feedback delay. To maintain prediction
accuracy for realistic SNR, noise reduction that employs
oversampled pilots is used prior to fading prediction. We
also propose a robust low pilot rate method that utilizes
interleaving to improve the spectral efficiency. Simulations
are presented for two channel models: the conventional Jakes
model and a realistic physical channel model where the
parameters associated with the reflectors vary in time and
the arrival rays have different strengths and asymmetric
arrival angles. © 2002-2012 IEEE.},
Doi = {10.1109/TWC.2012.101712.111884},
Key = {fds235783}
}

@article{fds235786,
Author = {Carson, WR and Chen, M and Rodrigues, MRD and Calderbank, R and Carin,
L},
Title = {Communications-inspired projection design with application
to compressive sensing},
Journal = {SIAM Journal on Imaging Sciences},
Volume = {5},
Number = {4},
Pages = {1182-1212},
Year = {2012},
ISSN = {1936-4954},
url = {http://hdl.handle.net/10161/8952 Duke open
access},
Abstract = {We consider the recovery of an underlying signal x ∈ ℂm
based on projection measurements of the form y = Mx+w, where
y ∈ ℂℓ and w is measurement noise; we are interested
in the case ℓ ≪ m. It is assumed that the signal model
p(x) is known and that w ~ CN(w; 0,Σw) for known Σ w. The
objective is to design a projection matrix M ∈ ℂℓ×m
to maximize key information-theoretic quantities with
operational significance, including the mutual information
between the signal and the projections I(x; y) or the Rényi
entropy of the projections hα (y) (Shannon entropy is a
special case). By capitalizing on explicit characterizations
of the gradients of the information measures with respect to
the projection matrix, where we also partially extend the
well-known results of Palomar and Verdu ́ from the mutual
information to the Rényi entropy domain, we reveal the key
operations carried out by the optimal projection designs:
mode exposure and mode alignment. Experiments are considered
for the case of compressive sensing (CS) applied to imagery.
In this context, we provide a demonstration of the
performance improvement possible through the application of
the novel projection designs in relation to conventional
ones, as well as justification for a fast online projection
design method with which state-of-the-art adaptive CS signal
recovery is achieved. © 2012 Society for Industrial and
Applied Mathematics.},
Doi = {10.1137/120878380},
Key = {fds235786}
}

@article{fds236001,
Author = {Jafarpour, S and Duarte, MF and Calderbank, R},
Title = {Beyond worst-case reconstruction in deterministic compressed
sensing},
Journal = {IEEE International Symposium on Information Theory -
Proceedings},
Pages = {1852-1856},
Year = {2012},
url = {http://dx.doi.org/10.1109/ISIT.2012.6283601},
Abstract = {The role of random measurement in compressive sensing is
analogous to the role of random codes in coding theory. In
coding theory, decoders that can correct beyond the minimum
distance of a code allow random codes to achieve the Shannon
limit. In compressed sensing, the counterpart of minimum
distance is the spark of the measurement matrix, i.e., the
size of the smallest set of linearly dependent columns. This
paper constructs a family of measurement matrices where the
columns are formed by exponentiating codewords from a
classical binary error-correcting code of block length M.
The columns can be partitioned into mutually unbiased bases,
and the spark of the corresponding measurement matrix is
shown to be O(√M) by identifying a configuration of
columns that plays a role similar to that of the Dirac comb
in classical Fourier analysis. Further, an explicit basis
for the null space of these measurement matrices is given in
terms of indicator functions of binary self-dual codes.
Reliable reconstruction of k-sparse inputs is shown for k of
order M/log(M) which is best possible and far beyond the
worst case lower bound provided by the spark. © 2012
IEEE.},
Doi = {10.1109/ISIT.2012.6283601},
Key = {fds236001}
}

@article{fds236002,
Author = {Zeng, M and Calderbank, R and Cui, S},
Title = {On design of rateless codes over dying binary erasure
channel},
Journal = {IEEE Transactions on Communications},
Volume = {60},
Number = {4},
Pages = {889-894},
Year = {2012},
ISSN = {0090-6778},
url = {http://dx.doi.org/10.1109/TCOMM.2012.022712.110038},
Abstract = {In this paper, we study a practical coding scheme for the
dying binary erasure channel (DBEC), which is a binary
erasure channel (BEC) subject to a random fatal failure. We
consider the rateless codes and optimize the degree
distribution to maximize the average recovery probability.
In particular, we first study the upper bound of the average
recovery probability, based on which we define the objective
function as the gap between the upper bound and the average
recovery probability achieved by a particular degree
distribution. We then seek the optimal degree distribution
by minimizing the objective function. A simple and heuristic
approach is also proposed to provide a suboptimal but good
degree distribution. Simulation results are presented to
show the significant performance gain over the conventional
LT codes. © 2012 IEEE.},
Doi = {10.1109/TCOMM.2012.022712.110038},
Key = {fds236002}
}

@article{fds236003,
Author = {Applebaum, L and Bajwa, WU and Duarte, MF and Calderbank,
R},
Title = {Asynchronous code-division random access using convex
optimization},
Journal = {Physical Communication},
Volume = {5},
Number = {2},
Pages = {129-147},
Year = {2012},
ISSN = {1874-4907},
url = {http://dx.doi.org/10.1016/j.phycom.2011.09.006},
Abstract = {Many applications in cellular systems and sensor networks
involve a random subset of a large number of users
asynchronously reporting activity to a base station. This
paper examines the problem of multiuser detection (MUD) in
random access channels for such applications. Traditional
orthogonal signaling ignores the random nature of user
activity in this problem and limits the total number of
users to be on the order of the number of signal space
dimensions. Contention-based schemes, on the other hand,
suffer from delays caused by colliding transmissions and the
hidden node problem. In contrast, this paper presents a
novel pairing of an asynchronous non-orthogonal
code-division random access scheme with a convex
optimization-based MUD algorithm that overcomes the issues
associated with orthogonal signaling and contention-based
methods. Two key distinguishing features of the proposed MUD
algorithm are that it does not require knowledge of the
delay or channel state information of every user and it has
polynomial-time computational complexity. The main
analytical contribution of this paper is the relationship
between the performance of the proposed MUD algorithm in the
presence of arbitrary or random delays and two simple
metrics of the set of user codewords. The study of these
metrics is then focused on two specific sets of codewords,
random binary codewords and specially constructed algebraic
codewords, for asynchronous random access. The ensuing
analysis confirms that the proposed scheme together with
either of these two codeword sets significantly outperforms
the orthogonal signaling-based random access in terms of the
total number of users in the system. © 2011 Elsevier
B.V.},
Doi = {10.1016/j.phycom.2011.09.006},
Key = {fds236003}
}

@article{fds236004,
Author = {Bajwa, WU and Calderbank, R and Mixon, DG},
Title = {Two are better than one: Fundamental parameters of frame
coherence},
Journal = {Applied and Computational Harmonic Analysis},
Volume = {33},
Number = {1},
Pages = {58-78},
Year = {2012},
ISSN = {1063-5203},
url = {http://dx.doi.org/10.1016/j.acha.2011.09.005},
Abstract = {This paper investigates two parameters that measure the
coherence of a frame: worst-case and average coherence. We
first use worst-case and average coherence to derive
near-optimal probabilistic guarantees on both sparse signal
detection and reconstruction in the presence of noise. Next,
we provide a catalog of nearly tight frames with small
worst-case and average coherence. Later, we find a new lower
bound on worst-case coherence; we compare it to the Welch
bound and use it to interpret recently reported signal
reconstruction results. Finally, we give an algorithm that
transforms frames in a way that decreases average coherence
without changing the spectral norm or worst-case coherence.
Doi = {10.1016/j.acha.2011.09.005},
Key = {fds236004}
}

@article{fds236005,
Author = {Wu, Y and Jia, T and Calderbank, R and Duel-Hallen, A and Hallen,
H},
Title = {Enabling Code Diversity for Mobile Radio Channels using
Journal = {IEEE Transactions on Wireless Communications},
Year = {2012},
ISSN = {1536-1276},
url = {http://dx.doi.org/10.1109/TWC.2012.101712.111884},
Abstract = {Code diversity integrates space-time coding with beamforming
by using a small number of feedback bits to select from a
family of space-time codes. Different codes lead to
different induced channels at the receiver, where Channel
State Information (CSI) is used to instruct the transmitter
how to choose the code. Feedback can be combined with
sub-optimal low complexity decoding of the component codes
to match Maximum-Likelihood (ML) decoding performance of any
individual code in the family. It can also be combined with
ML decoding of the component codes to improve performance
beyond ML decoding performance of any individual code. Prior
analysis of code diversity did not take into account the
effect of the mobile speed and the delay in the feedback
channel. This paper demonstrates the practicality of code
diversity in space-time coded systems by showing that
performance gains based on instantaneous feedback are
largely preserved when long-range prediction of time-varying
correlated fading channels is employed to compensate for the
effect of the feedback delay. To maintain prediction
accuracy for realistic SNR, noise reduction that employs
oversampled pilots is used prior to fading prediction. We
also propose a robust low pilot rate method that utilizes
interleaving to improve the spectral efficiency. Simulations
are presented for two channel models: the conventional Jakes
model and a realistic physical channel model where the
parameters associated with the reflectors vary in time and
the arrival rays have different strengths and asymmetric
arrival angles.},
Doi = {10.1109/TWC.2012.101712.111884},
Key = {fds236005}
}

@article{fds236077,
Author = {Chen, M and Carson, W and Rodrigues, M and Calderbank, R and Carin,
L},
Title = {Communications inspired linear discriminant
analysis},
Journal = {Proceedings of the 29th International Conference on Machine
Learning, ICML 2012},
Volume = {1},
Pages = {919-926},
Year = {2012},
url = {http://hdl.handle.net/10161/8956 Duke open
access},
Abstract = {We study the problem of supervised linear dimensionality
reduction, taking an information-theoretic viewpoint. The
linear projection matrix is designed by maximizing the
mutual information between the projected signal and the
class label. By harnessing a recent theoretical result on
the gradient of mutual information, the above optimization
problem can be solved directly using gradient descent,
without requiring simplification of the objective function.
Theoretical analysis and empirical comparison are made
between the proposed method and two closely related methods,
and comparisons are also made with a method in which Rényi
entropy is used to define the mutual information (in this
case the gradient may be computed simply, under a special
parameter setting). Relative to these alternative
approaches, the proposed method achieves promising results
on real datasets. Copyright 2012 by the author(s)/owner(s).},
Key = {fds236077}
}

@article{fds236078,
Author = {Chi, Y and Eldar, YC and Calderbank, R},
Title = {PETRELS: Subspace estimation and tracking from partial
observations},
Journal = {IEEE International Conference on Acoustics Speech and Signal
Processing},
Pages = {3301-3304},
Year = {2012},
ISSN = {1520-6149},
url = {http://dx.doi.org/10.1109/ICASSP.2012.6288621},
Abstract = {We consider the problem of reconstructing a data stream from
a small subset of its entries, where the data stream is
assumed to lie in a low-dimensional linear subspace,
possibly corrupted by noise. It is also important to track
the change of underlying subspace for many applications.
This problem can be viewed as a sequential low-rank matrix
completion problem in which the subspace is learned in an
online fashion. The proposed algorithm, called Parallel
Estimation and Tracking by REcursive Least Squares
(PETRELS), identifies the underlying low-dimensional
subspace via a recursive procedure for each row of the
subspace matrix in parallel, and then reconstructs the
missing entries via least-squares estimation if required.
PETRELS outperforms previous approaches by discounting
observations in order to capture long-term behavior of the
data stream and be able to adapt to it. Numerical examples
are provided for direction-of-arrival estimation and matrix
completion, comparing PETRELS with state of the art batch
algorithms. © 2012 IEEE.},
Doi = {10.1109/ICASSP.2012.6288621},
Key = {fds236078}
}

@article{fds236079,
Author = {Qureshi, TR and Zoltowski, MD and Calderbank, R},
Title = {A novel approach to Doppler compensation and estimation for
multiple targets in MIMO radar with unitary waveform matrix
scheduling},
Journal = {IEEE International Conference on Acoustics Speech and Signal
Processing},
Pages = {2473-2476},
Year = {2012},
ISSN = {1520-6149},
url = {http://dx.doi.org/10.1109/ICASSP.2012.6288417},
Abstract = {In this paper, we present a method of detecting the range
and Doppler phase of a point target using multiple antennas.
As a key illustrative example, we consider a 4 x 4 system
employing a unitary matrix waveform set, e.g., formed from
Golay complementary sequences. When a non-negligible Doppler
shift is induced by the target motion, the waveform matrix
formed from the complementary sequences is no longer
unitary, resulting in significantly degraded target range
estimates. To solve this problem, we adopt a subspace based
approach exploiting the observation that the receive matrix
formed from matched filtering of the reflected waveforms has
a (non-trivial) null-space. Through processing of the
waveforms with the appropriate vector from the null-space,
we can significantly improve the range detection
performance. Also, another very important target aspect is
the velocity with which the target is moving, and to
determine that, the exact Doppler phase shift induced by the
target motion needs to be estimated with reasonable
accuracy. To accomplish this task, we develop a strategy
that uses the MUSIC algorithm to estimate the Doppler phase,
and we use simulations to show that the phase estimates
obtained are reasonably accurate even at low SNRs. © 2012
IEEE.},
Doi = {10.1109/ICASSP.2012.6288417},
Key = {fds236079}
}

@article{fds236080,
Author = {Carson, WR and Rodrigues, MRD and Chen, M and Carin, L and Calderbank,
R},
Title = {How to focus the discriminative power of a
dictionary},
Journal = {IEEE International Conference on Acoustics Speech and Signal
Processing},
Pages = {1365-1368},
Year = {2012},
ISSN = {1520-6149},
url = {http://dx.doi.org/10.1109/ICASSP.2012.6288144},
Abstract = {This paper is motivated by the challenge of high fidelity
processing of images using a relatively small set of
projection measurements. This is a problem of great interest
in many sensing applications, for example where high
photodetector counts are precluded by a combination of
available power, form factor and expense. The emerging
methods of dictionary learning and compressive sensing offer
great potential for addressing this challenge. Combining
these methods requires that the signals of interest be
representable as a sparse combination of elements of some
dictionary. This paper develops a method that aligns the
discriminative power of such a dictionary with the physical
limitations of the imaging system. Alignment is accomplished
by designing a projection matrix that exposes and then
aligns the modes of the noise with those of the dictionary.
The design algorithm is obtained by modifying an algorithm
for designing the pre-filter to maximize the rate and
reliability of a Multiple Input Multiple Output (MIMO)
communications channel. The difference is that in the
communications problem a source is being matched to a
channel, whereas in the imaging problem a channel, or
equivalently the noise covariance, is being matched to a
source. Our results shown that using the proposed
communications design framework we can reduce reconstruction
error between 20%, after only 20 projections of a 28 x 28
image, and 10% after 100 projections. Furthermore, we
noticeably see the superior quality of the reconstructed
images. © 2012 IEEE.},
Doi = {10.1109/ICASSP.2012.6288144},
Key = {fds236080}
}

@article{fds236081,
Author = {Nokleby, M and Bajwa, WU and Calderbank, R and Aazhang,
B},
Title = {Hierarchical averaging over wireless sensor
networks},
Journal = {IEEE International Conference on Acoustics Speech and Signal
Processing},
Pages = {3121-3124},
Year = {2012},
ISSN = {1520-6149},
url = {http://dx.doi.org/10.1109/ICASSP.2012.6288576},
Abstract = {We introduce an approach to gossip algorithms that exploits
three aspects of the wireless medium: superposition,
broadcast, and power control. Instead of sending pairwise
messages between neighbors on a fixed network topology, we
construct gossip algorithms in which nodes can
simultaneously recover multiple neighbors' messages and in
which nodes can adjust the set of their neighbors by
adjusting transmit power. We present two averaging
algorithms, each based on a hierarchical clustering of the
network. In the first algorithm, clusters of nodes transmit
their estimates locally and randomly select a representative
node for communications at the next level. In the second,
each cluster mutually averages and then cooperatively
transmits at the next level. For path-loss environments,
these schemes achieve order-optimal or near order-optimal
performance. © 2012 IEEE.},
Doi = {10.1109/ICASSP.2012.6288576},
Key = {fds236081}
}

@article{fds236082,
Author = {Xie, Y and Chi, Y and Applebaum, L and Calderbank,
R},
Title = {Compressive demodulation of mutually interfering
signals},
Journal = {2012 IEEE Statistical Signal Processing Workshop, SSP
2012},
Pages = {592-595},
Year = {2012},
url = {http://dx.doi.org/10.1109/SSP.2012.6319768},
Abstract = {The challenge of Multiuser Detection (MUD) is that of
demodulating mutually interfering signals given that at any
time instant the number of active users is typically small.
The promise of compressed sensing is the demodulation of
sparse superpositions of signature waveforms from very few
measurements. This paper considers signature waveforms that
are are drawn from a Gabor frame. It describes a MUD
architecture that uses subsampling to convert analog input
to a digital signal, and then uses iterative matching
pursuit to recover the active users. Compressive
demodulation requires K logN samples to recover K active
users whereas standard MUD requires N samples. The paper
provides theoretical performance guarantees and consistent
numerical simulations. © 2012 IEEE.},
Doi = {10.1109/SSP.2012.6319768},
Key = {fds236082}
}

@article{fds236083,
Author = {Calderbank, R and Jafarpour, S},
Title = {Finding needles in compressed haystacks},
Journal = {IEEE International Conference on Acoustics Speech and Signal
Processing},
Pages = {3441-3444},
Year = {2012},
ISSN = {1520-6149},
url = {http://dx.doi.org/10.1109/ICASSP.2012.6288656},
Abstract = {In this paper, we investigate the problem of compressed
learning, i.e. learning directly in the compressed domain.
In particular, we provide tight bounds demonstrating that
the linear kernel SVMs classifier in the measurement domain,
with high probability, has true accuracy close to the
accuracy of the best linear threshold classifier in the data
domain. Furthermore, we indicate that for a family of
well-known deterministic compressed sensing matrices,
compressed learning is provided on the fly. Finally, we
support our claims with experimental results in the texture
analysis application. © 2012 IEEE.},
Doi = {10.1109/ICASSP.2012.6288656},
Key = {fds236083}
}

@article{fds236084,
Author = {Duarte, MF and Matthews, TE and Warren, WS and Calderbank,
R},
Title = {Melanoma classification from hidden Markov tree
features},
Journal = {IEEE International Conference on Acoustics Speech and Signal
Processing},
Pages = {685-688},
Year = {2012},
ISSN = {1520-6149},
url = {http://dx.doi.org/10.1109/ICASSP.2012.6287976},
Abstract = {Melanoma detection relies on visual inspection of skin
samples under the microscope via a qualitative set of
indicators, causing large discordance among pathologists.
New developments in pump-probe imaging enable the extraction
of melanin intensity levels from skin samples and provide
baseline qualitative figures for melanoma detection and
classification. However, such basic figures do not capture
the diverse types of cellular structure that distinguish
different stages of melanoma. In this paper, we propose an
initial approach for feature extraction for classification
purposes via Hidden Markov Tree models trained on skin
sample melanin intensity images. Our experimental results
show that the proposed features provide a mathematical
microscope that is able to better discriminate cellular
structure, enabling successful classification of skin
samples that are mislabeled when the baseline melanin
intensity qualitative figures are used. © 2012
IEEE.},
Doi = {10.1109/ICASSP.2012.6287976},
Key = {fds236084}
}

@article{fds303202,
Author = {Harms, A and Bajwa, WU and Calderbank, R},
Title = {A Constrained Random Demodulator for Sub-Nyquist
Sampling},
Year = {2012},
Month = {April},
url = {http://arxiv.org/abs/1204.0839v3},
Abstract = {This paper presents a significant modification to the Random
Demodulator (RD) of Tropp et al. for sub-Nyquist sampling of
frequency-sparse signals. The modification, termed
constrained random demodulator, involves replacing the
random waveform, essential to the operation of the RD, with
a constrained random waveform that has limits on its
switching rate because fast switching waveforms may be hard
to generate cleanly. The result is a relaxation on the
hardware requirements with a slight, but manageable,
decrease in the recovery guarantees. The paper also
establishes the importance of properly choosing the
statistics of the constrained random waveform. If the power
spectrum of the random waveform matches the distribution on
the tones of the input signal (i.e., the distribution is
proportional to the power spectrum), then recovery of the
input signal tones is improved. The theoretical guarantees
provided in the paper are validated through extensive
numerical simulations and phase transition
plots.},
Doi = {10.1109/TSP.2012.2231077},
Key = {fds303202}
}

@article{fds303201,
Author = {Chi, Y and Eldar, YC and Calderbank, R},
Title = {PETRELS: Parallel Subspace Estimation and Tracking by
Recursive Least Squares from Partial Observations},
Year = {2012},
Month = {July},
url = {http://arxiv.org/abs/1207.6353v2},
Abstract = {Many real world data sets exhibit an embedding of
low-dimensional structure in a high-dimensional manifold.
Examples include images, videos and internet traffic data.
It is of great significance to reduce the storage
requirements and computational complexity when the data
dimension is high. Therefore we consider the problem of
reconstructing a data stream from a small subset of its
entries, where the data is assumed to lie in a
low-dimensional linear subspace, possibly corrupted by
noise. We further consider tracking the change of the
underlying subspace, which can be applied to applications
such as video denoising, network monitoring and anomaly
detection. Our problem can be viewed as a sequential
low-rank matrix completion problem in which the subspace is
learned in an on-line fashion. The proposed algorithm,
dubbed Parallel Estimation and Tracking by REcursive Least
Squares (PETRELS), first identifies the underlying
low-dimensional subspace via a recursive procedure for each
row of the subspace matrix in parallel with discounting for
previous observations, and then reconstructs the missing
entries via least-squares estimation if required. Numerical
examples are provided for direction-of-arrival estimation
and matrix completion, comparing PETRELS with state of the
art batch algorithms.},
Doi = {10.1109/TSP.2013.2282910},
Key = {fds303201}
}

@article{fds303200,
Author = {Nokleby, M and Bajwa, WU and Calderbank, R and Aazhang,
B},
Title = {Toward Resource-Optimal Consensus over the Wireless
Medium},
Year = {2012},
Month = {August},
url = {http://arxiv.org/abs/1208.3251v2},
Abstract = {We carry out a comprehensive study of the resource cost of
averaging consensus in wireless networks. Most previous
approaches suppose a graphical network, which abstracts away
crucial features of the wireless medium, and measure
resource consumption only in terms of the total number of
transmissions required to achieve consensus. Under a
path-loss dominated model, we study the resource
requirements of consensus with respect to three
wireless-appropriate metrics: total transmit energy, elapsed
time, and time-bandwidth product. First we characterize the
performance of several popular gossip algorithms, showing
that they may be order-optimal with respect to transmit
energy but are strictly suboptimal with respect to elapsed
time and time-bandwidth product. Further, we propose a new
consensus scheme, termed hierarchical averaging, and show
that it is nearly order-optimal with respect to all three
metrics. Finally, we examine the effects of quantization,
showing that hierarchical averaging provides a nearly
order-optimal tradeoff between resource consumption and
quantization error.},
Doi = {10.1109/JSTSP.2013.2246765},
Key = {fds303200}
}

@article{fds303203,
Author = {Chi, Y and Calderbank, R},
Title = {Coherence-Based Performance Guarantees of Orthogonal
Matching Pursuit},
Year = {2012},
Month = {September},
url = {http://arxiv.org/abs/1209.6267v1},
Abstract = {In this paper, we present coherence-based performance
guarantees of Orthogonal Matching Pursuit (OMP) for both
support recovery and signal reconstruction of sparse signals
when the measurements are corrupted by noise. In particular,
two variants of OMP either with known sparsity level or with
a stopping rule are analyzed. It is shown that if the
measurement matrix $X\in\mathbb{C}^{n\times p}$ satisfies
the strong coherence property, then with
$n\gtrsim\mathcal{O}(k\log p)$, OMP will recover a
$k$-sparse signal with high probability. In particular, the
performance guarantees obtained here separate the properties
required of the measurement matrix from the properties
required of the signal, which depends critically on the
minimum signal to noise ratio rather than the power profiles
of the signal. We also provide performance guarantees for
partial support recovery. Comparisons are given with other
performance guarantees for OMP using worst-case analysis and
the sorted one step thresholding algorithm.},
Key = {fds303203}
}

@article{fds235778,
Author = {Jacobvitz, AN and Calderbank, R and Sorin, DJ},
Title = {Coset coding to extend the lifetime of memory},
Journal = {Proceedings - International Symposium on High-Performance
Computer Architecture},
Pages = {222-233},
Year = {2013},
ISSN = {1530-0897},
url = {http://dx.doi.org/10.1109/HPCA.2013.6522321},
Abstract = {Some recent memory technologies, including phase change
memory (PCM), have lifetime reliabilities that are affected
by write operations. We propose the use of coset coding to
extend the lifetimes of these memories. The key idea of
coset coding is that it performs a one-to-many mapping from
each dataword to a coset of vectors, and having multiple
possible vectors provides the flexibility to choose the
vector to write that optimizes lifetime. Our technique,
FlipMin, uses coset coding and, for each write, selects the
vector that minimizes the number of bits that must flip. We
also show how FlipMin can be synergistically combined with
the ability to tolerate bit erasures. Thus, our techniques
help to prevent bits from wearing out and can then tolerate
those bits that do wear out. © 2013 IEEE.},
Doi = {10.1109/HPCA.2013.6522321},
Key = {fds235778}
}

@article{fds235782,
Author = {Duarte, MF and Jafarpour, S and Calderbank, AR},
Title = {Performance of the Delsarte-Goethals frame on clustered
sparse vectors},
Journal = {IEEE Transactions on Signal Processing},
Volume = {61},
Number = {8},
Pages = {1998-2008},
Year = {2013},
ISSN = {1053-587X},
url = {http://dx.doi.org/10.1109/TSP.2013.2242064},
Abstract = {The Delsarte-Goethals frame (DGF) has been proposed for
deterministic compressive sensing of sparse and compressible
signals. Results in compressive sensing theory show that the
DGF enables successful recovery of an overwhelming majority
of sufficiently sparse signals. However, these results do
not give a characterization of the sparse vectors for which
the recovery procedure fails. In this paper, we present a
formal analysis of the DGF that highlights the presence of
clustered sparse vectors within its null space. This in turn
implies that sparse recovery performance is diminished for
sparse vectors that have their nonzero entries clustered
together. Such clustered structure is present in compressive
imaging applications, where commonly-used raster scannings
of 2-D discrete wavelet transform representations yield
clustered sparse representations for natural images. Prior
work leverages this structure by proposing specially
tailored sparse recovery algorithms that partition the
recovery of the input vector into known clustered and
unclustered portions. Alternatively, we propose new
randomized and deterministic raster scannings for clustered
coefficient vectors that improve recovery performance.
Experimental results verify the aforementioned analysis and
confirm the predicted improvements for both noiseless and
noisy measurement regimes. © 1991-2012 IEEE.},
Doi = {10.1109/TSP.2013.2242064},
Key = {fds235782}
}

@article{fds235761,
Author = {Wang, L and Carlson, D and Rodrigues, MD and Wilcox, D and Calderbank,
R and Carin, L},
Title = {Designed measurements for vector count data},
Journal = {Advances in Neural Information Processing
Systems},
Year = {2013},
Month = {January},
ISSN = {1049-5258},
Abstract = {We consider design of linear projection measurements for a
vector Poisson signal model. The projections are performed
on the vector Poisson rate,X ∈ ℝ + n , and the observed
data are a vector of counts, Y ∈ ℤ + m . The projection
matrix is designed by maximizing mutual information between
Y and X, I(Y;X). When there is a latent class label C ∈
{1; : : : ;L} associated with X, we onsider the mutual
information with respect to Y and C, I(Y ;C). New analytic
expressions for the gradient of I(Y ;X) and I(Y ;C) are
presented, with gradient performed with respect to the
measurement matrix. Connections are made to the more widely
studied Gaussian measurement model. Example results are
presented for compressive topic modeling of a document
corpora (word counting), and hyperspectral compressive
sensing for chemical classification (photon
counting).},
Key = {fds235761}
}

@article{fds322367,
Author = {Nokleby, M and Bajwa, WU and Calderbank, R and Aazhang,
B},
Title = {Toward resource-optimal consensus over the wireless
medium},
Journal = {IEEE Journal of Selected Topics in Signal
Processing},
Volume = {7},
Number = {2},
Pages = {284-295},
Year = {2013},
Month = {January},
url = {http://dx.doi.org/10.1109/JSTSP.2013.2246765},
Abstract = {We carry out a comprehensive study of the resource cost of
averaging consensus in wireless networks. Most previous
approaches suppose a graphical network, which abstracts away
crucial features of the wireless medium, and measure
resource consumption only in terms of the total number of
transmissions required to achieve consensus. Under a
path-loss model, we study the resource requirements of
consensus with respect to three wireless- appropriate
metrics: total transmit energy, elapsed time, and
time-bandwidth product. First, we characterize the
performance of several popular gossip algorithms, showing
that they may be order-optimal with respect to transmit
energy but are strictly suboptimal with respect to elapsed
time and time-bandwidth product. Further, we propose a new
consensus scheme, termed hierarchical averaging, and show
that it is nearly order-optimal with respect to all three
metrics. Finally, we examine the effects of quantization,
showing that hierarchical averaging provides a nearly
orderoptimal tradeoff between resource consumption and
quantization error. © 2013 IEEE.},
Doi = {10.1109/JSTSP.2013.2246765},
Key = {fds322367}
}

@article{fds303199,
Author = {Reboredo, H and Renna, F and Calderbank, R and Rodrigues,
MRD},
Title = {Compressive Classification},
Year = {2013},
Month = {February},
url = {http://arxiv.org/abs/1302.4660v1},
Abstract = {This paper derives fundamental limits associated with
compressive classification of Gaussian mixture source
models. In particular, we offer an asymptotic
characterization of the behavior of the (upper bound to the)
misclassification probability associated with the optimal
Maximum-A-Posteriori (MAP) classifier that depends on
quantities that are dual to the concepts of diversity gain
and coding gain in multi-antenna communications. The
diversity, which is shown to determine the rate at which the
probability of misclassification decays in the low noise
regime, is shown to depend on the geometry of the source,
the geometry of the measurement system and their interplay.
The measurement gain, which represents the counterpart of
the coding gain, is also shown to depend on geometrical
quantities. It is argued that the diversity order and the
measurement gain also offer an optimization criterion to
perform dictionary learning for compressive classification
applications.},
Key = {fds303199}
}

@article{fds303198,
Author = {Goparaju, S and Rouayheb, SE and Calderbank, R and Poor,
HV},
Title = {Data Secrecy in Distributed Storage Systems under Exact
Repair},
Year = {2013},
Month = {April},
url = {http://arxiv.org/abs/1304.3156v2},
Abstract = {The problem of securing data against eavesdropping in
distributed storage systems is studied. The focus is on
systems that use linear codes and implement exact repair to
recover from node failures.The maximum file size that can be
stored securely is determined for systems in which all the
available nodes help in repair (i.e., repair degree $d=n-1$,
where $n$ is the total number of nodes) and for any number
of compromised nodes. Similar results in the literature are
restricted to the case of at most two compromised nodes.
Moreover, new explicit upper bounds are given on the maximum
secure file size for systems with $d<n-1$. The key
ingredients for the contribution of this paper are new
results on subspace intersection for the data downloaded
during repair. The new bounds imply the interesting fact
that the maximum data that can be stored securely decreases
exponentially with the number of compromised
nodes.},
Key = {fds303198}
}

@article{fds303197,
Author = {Goparaju, S and Tamo, I and Calderbank, R},
Title = {An Improved Sub-Packetization Bound for Minimum Storage
Regenerating Codes},
Year = {2013},
Month = {May},
url = {http://arxiv.org/abs/1305.3498v1},
Abstract = {Distributed storage systems employ codes to provide
resilience to failure of multiple storage disks.
Specifically, an $(n, k)$ MDS code stores $k$ symbols in $n$
disks such that the overall system is tolerant to a failure
of up to $n-k$ disks. However, access to at least $k$ disks
is still required to repair a single erasure. To reduce
repair bandwidth, array codes are used where the stored
symbols or packets are vectors of length $\ell$. MDS array
codes have the potential to repair a single erasure using a
fraction $1/(n-k)$ of data stored in the remaining disks. We
introduce new methods of analysis which capitalize on the
translation of the storage system problem into a geometric
problem on a set of operators and subspaces. In particular,
we ask the following question: for a given $(n, k)$, what is
the minimum vector-length or sub-packetization factor $\ell$
required to achieve this optimal fraction? For \emph{exact
recovery} of systematic disks in an MDS code of low
redundancy, i.e. $k/n > 1/2$, the best known explicit codes
\cite{WTB12} have a sub-packetization factor $\ell$ which is
exponential in $k$. It has been conjectured \cite{TWB12}
that for a fixed number of parity nodes, it is in fact
necessary for $\ell$ to be exponential in $k$. In this
paper, we provide a new log-squared converse bound on $k$
for a given $\ell$, and prove that $k \le 2\log_2\ell\left(\log_{\delta}\ell+1\right)$, for an
arbitrary number of parity nodes $r = n-k$, where $\delta = r/(r-1)$.},
Key = {fds303197}
}

@article{fds303196,
Author = {Renna, F and Calderbank, R and Carin, L and Rodrigues,
MRD},
Title = {Reconstruction of Signals Drawn from a Gaussian Mixture from
Noisy Compressive Measurements},
Year = {2013},
Month = {July},
url = {http://arxiv.org/abs/1307.0861v2},
Abstract = {This paper determines to within a single measurement the
minimum number of measurements required to successfully
reconstruct a signal drawn from a Gaussian mixture model in
the low-noise regime. The method is to develop upper and
lower bounds that are a function of the maximum dimension of
the linear subspaces spanned by the Gaussian mixture
components. The method not only reveals the existence or
absence of a minimum mean-squared error (MMSE) error floor
(phase transition) but also provides insight into the MMSE
decay via multivariate generalizations of the MMSE dimension
and the MMSE power offset, which are a function of the
interaction between the geometrical properties of the kernel
and the Gaussian mixture. These results apply not only to
standard linear random Gaussian measurements but also to
linear kernels that minimize the MMSE. It is shown that
optimal kernels do not change the number of measurements
associated with the MMSE phase transition, rather they
affect the sensed power required to achieve a target MMSE in
the low-noise regime. Overall, our bounds are tighter and
sharper than standard bounds on the minimum number of
measurements needed to recover sparse signals associated
with a union of subspaces model, as they are not asymptotic
in the signal dimension or signal sparsity.},
Doi = {10.1109/TSP.2014.2309560},
Key = {fds303196}
}

@article{fds303195,
Author = {Calderbank, R and Thompson, A and Xie, Y},
Title = {On block coherence of frames},
Year = {2013},
Month = {July},
url = {http://arxiv.org/abs/1307.7544v4},
Abstract = {Block coherence of matrices plays an important role in
analyzing the performance of block compressed sensing
recovery algorithms (Bajwa and Mixon, 2012). In this paper,
we characterize two block coherence metrics: worst-case and
average block coherence. First, we present lower bounds on
worst-case block coherence, in both the general case and
also when the matrix is constrained to be a union of
orthobases. We then present deterministic matrix
constructions based upon Kronecker products which obtain
these lower bounds. We also characterize the worst-case
block coherence of random subspaces. Finally, we present a
flipping algorithm that can improve the average block
coherence of a matrix, while maintaining the worst-case
block coherence of the original matrix. We provide numerical
examples which demonstrate that our proposed deterministic
matrix construction performs well in block compressed
sensing.},
Key = {fds303195}
}

@article{fds235773,
Author = {Renna, F and Rodrigues, MRD and Chen, M and Calderbank, R and Carin,
L},
Title = {Compressive sensing for incoherent imaging systems with
optical constraints},
Journal = {IEEE International Conference on Acoustics Speech and Signal
Processing},
Pages = {5484-5488},
Year = {2013},
Month = {October},
ISSN = {1520-6149},
url = {http://dx.doi.org/10.1109/ICASSP.2013.6638712},
Abstract = {We consider the problem of linear projection design for
incoherent optical imaging systems. We propose a
computationally efficient method to obtain effective
measurement kernels that satisfy the physical constraints
imposed by an optical system, starting first from arbitrary
kernels, including those that satisfy a less demanding power
constraint. Performance is measured in terms of mutual
information between the source input and the projection
measurement, as well as reconstruction error for real world
images. A clear improvement in the quality of image
reconstructions is shown with respect to both random and
adaptive projection designs in the literature. © 2013
IEEE.},
Doi = {10.1109/ICASSP.2013.6638712},
Key = {fds235773}
}

@article{fds235774,
Author = {Wang, M and Xu, W and Calderbank, R},
Title = {Compressed sensing with corrupted participants},
Journal = {IEEE International Conference on Acoustics Speech and Signal
Processing},
Pages = {4653-4657},
Year = {2013},
Month = {October},
ISSN = {1520-6149},
url = {http://dx.doi.org/10.1109/ICASSP.2013.6638542},
Abstract = {Compressed sensing (CS) theory promises one can recover
real-valued sparse signal from a small number of linear
measurements. Motivated by network monitoring with link
failures, we for the first time consider the problem of
recovering signals that contain both real-valued entries and
corruptions, where the real entries represent transmission
delays on normal links and the corruptions represent failed
links. Unlike conventional CS, here a measurement is
real-valued only if it does not include a failed link, and
it is corrupted otherwise. We prove that O((d + 1)max(d, k)
log n) nonadaptive measurements are enough to recover all
n-dimensional signals that contain k nonzero real entries
and d corruptions. We provide explicit constructions of
measurements and recovery algorithms. We also analyze the
performance of signal recovery when the measurements contain
errors. © 2013 IEEE.},
Doi = {10.1109/ICASSP.2013.6638542},
Key = {fds235774}
}

@article{fds235775,
Author = {Chi, Y and Calderbank, R},
Title = {Knowledge-enhanced matching pursuit},
Journal = {IEEE International Conference on Acoustics Speech and Signal
Processing},
Pages = {6576-6580},
Year = {2013},
Month = {October},
ISSN = {1520-6149},
url = {http://dx.doi.org/10.1109/ICASSP.2013.6638933},
Abstract = {Compressive Sensing is possible when the sensing matrix acts
as a near isometry on signals of interest that can be
sparsely or compressively represented. The attraction of
greedy algorithms such as Orthogonal Matching Pursuit is
their simplicity. However they fail to take advantage of
both the structure of the sensing matrix and any prior
information about the sparse signal. This paper introduces
an oblique projector to matching pursuit algorithms to
enhance detection of a component that is present in the
signal by reducing interference from other candidate
components based on prior information about the signal as
well as the structure of the sensing matrix. Numerical
examples demonstrate that performance as a function of SNR
is superior to conventional matching pursuit. © 2013
IEEE.},
Doi = {10.1109/ICASSP.2013.6638933},
Key = {fds235775}
}

@article{fds235764,
Author = {Xie, Y and Chi, Y and Calderbank, R},
Title = {Low-rank matrix recovery with poison noise},
Journal = {2013 IEEE Global Conference on Signal and Information
Processing, GlobalSIP 2013 - Proceedings},
Pages = {622},
Year = {2013},
Month = {December},
url = {http://dx.doi.org/10.1109/GlobalSIP.2013.6736959},
Abstract = {Estimating an image M* + m 1 ×m 2 from its linear
measurements under Poisson noise is an important problem
arises from applications such as optical imaging, nuclear
medicine and x-ray imaging [1]. When the image M* has a
low-rank structure, we can use a small number of linear
measurements to recover M*, also known as low-rank matrix
recovery. This is related to compressed sensing, where the
goal is to develop efficient data acquisition systems by
exploiting sparsity of underlying signals. © 2013
IEEE.},
Doi = {10.1109/GlobalSIP.2013.6736959},
Key = {fds235764}
}

@article{fds235765,
Author = {Wu, T and Polatkan, G and Steel, D and Brown, W and Daubechies, I and Calderbank, R},
Title = {Painting analysis using wavelets and probabilistic topic
models},
Journal = {2013 IEEE International Conference on Image Processing, ICIP
2013 - Proceedings},
Pages = {3264-3268},
Year = {2013},
Month = {December},
url = {http://dx.doi.org/10.1109/ICIP.2013.6738672},
Abstract = {In this paper, computer-based techniques for stylistic
analysis of paintings are applied to the five panels of the
14th century Peruzzi Altarpiece by Giotto di Bondone.
Features are extracted by combining a dual-tree complex
wavelet transform with a hidden Markov tree (HMT) model.
Hierarchical clustering is used to identify stylistic
keywords in image patches, and keyword frequencies are
calculated for sub-images that each contains many patches. A
generative hierarchical Bayesian model learns stylistic
patterns of keywords; these patterns are then used to
characterize the styles of the sub-images; this in turn,
permits to discriminate between paintings. Results suggest
that such unsupervised probabilistic topic models can be
useful to distill characteristic elements of style. © 2013
IEEE.},
Doi = {10.1109/ICIP.2013.6738672},
Key = {fds235765}
}

@article{fds235766,
Author = {Renna, F and Calderbank, R and Carin, L and Rodrigues,
MRD},
Title = {Reconstruction of Gaussian mixture models from compressive
measurements: A phase transition view},
Journal = {2013 IEEE Global Conference on Signal and Information
Processing, GlobalSIP 2013 - Proceedings},
Pages = {628},
Year = {2013},
Month = {December},
url = {http://dx.doi.org/10.1109/GlobalSIP.2013.6736965},
Abstract = {We characterize the minimum number of measurements needed to
drive to zero the minimum mean squared error (MMSE) of
Gaussian mixture model (GMM) input signals in the low-noise
regime. The result also hints at almost phase-transition
optimal recovery procedures based on a classification and
reconstruction approach. © 2013 IEEE.},
Doi = {10.1109/GlobalSIP.2013.6736965},
Key = {fds235766}
}

@article{fds235767,
Author = {Reboredo, H and Renna, F and Calderbank, R and Rodrigues,
MRD},
Title = {Projections designs for compressive classification},
Journal = {2013 IEEE Global Conference on Signal and Information
Processing, GlobalSIP 2013 - Proceedings},
Pages = {1029-1032},
Year = {2013},
Month = {December},
url = {http://dx.doi.org/10.1109/GlobalSIP.2013.6737069},
Abstract = {This paper puts forth projections designs for compressive
classification of Gaussian mixture models. In particular, we
capitalize on the asymptotic characterization of the
behavior of an (upper bound to the) misclassification
probability associated with the optimal Maximum-A-Posteriori
(MAP) classifier, which depends on quantities that are dual
to the concepts of the diversity gain and coding gain in
multi-antenna communications, to construct measurement
designs that maximize the diversity-order of the measurement
model. Numerical results demonstrate that the new
measurement designs substantially outperform random
measurements. Overall, the analysis and the designs cast
geometrical insight about the mechanics of compressive
classification problems. © 2013 IEEE.},
Doi = {10.1109/GlobalSIP.2013.6737069},
Key = {fds235767}
}

@article{fds235770,
Author = {Nokleby, M and Calderbank, R and Rodrigues, MRD},
Title = {Information-theoretic limits on the classification of
Gaussian mixtures: Classification on the Grassmann
manifold},
Journal = {2013 IEEE Information Theory Workshop, ITW
2013},
Year = {2013},
Month = {December},
url = {http://dx.doi.org/10.1109/ITW.2013.6691253},
Abstract = {Motivated by applications in high-dimensional signal
processing, we derive fundamental limits on the performance
of compressive linear classifiers. By analogy with Shannon
theory, we define the classification capacity, which
quantifies the maximum number of classes that can be
discriminated with low probability of error, and the
diversity-discrimination tradeoff, which quantifies the
tradeoff between the number of classes and the probability
of classification error. For classification of Gaussian
mixture models, we identify a duality between classification
and communications over non-coherent multiple-antenna
channels. This duality allows us to characterize the
classification capacity and diversity-discrimination
tradeoff using existing results from multiple-antenna
communication. We also identify the easiest possible
classification problems, which correspond to low-dimensional
subspaces drawn from an appropriate Grassmann manifold. ©
2013 IEEE.},
Doi = {10.1109/ITW.2013.6691253},
Key = {fds235770}
}

@article{fds235776,
Author = {Goparaju, S and Calderbank, R},
Title = {A new sub-packetization bound for minimum storage
regenerating codes},
Journal = {IEEE International Symposium on Information Theory -
Proceedings},
Pages = {1616-1620},
Year = {2013},
Month = {December},
ISSN = {2157-8095},
url = {http://dx.doi.org/10.1109/ISIT.2013.6620500},
Abstract = {Codes for distributed storage systems are often designed to
sustain failure of multiple storage disks. Specifically, an
(n, k) MDS code stores k symbols in n disks such that the
overall system is tolerant to a failure of up to n - k
disks. However, access to at least k disks is still required
to repair a single erasure. To reduce repair bandwidth,
array codes are used where the stored symbols or packets are
vectors of length ℓ. MDS array codes can potentially
repair a single erasure using a fraction l/(n - k) of data
stored in the surviving nodes. We ask the following
question: for a given (n, k), what is the minimum
vector-length or sub-packetization factor ℓ required to
achieve this optimal fraction? For exact recovery of
systematic disks in an MDS code of low redundancy, i.e. k/n
> 1/2, the best known explicit codes [1] have a
sub-packetization factor I which is exponential in k. It has
been conjectured [2] that for a fixed number of parity
nodes, it is in fact necessary for ℓ to be exponential in
k. In this paper, we provide new converse bounds on k for a
given ℓ We prove that k ≤ ℓ 2 for an arbitrary but
fixed number of parity nodes r = n ™ k. For the practical
case of 2 parity nodes, we prove a stronger result that k
≤ 4ℓ. © 2013 IEEE.},
Doi = {10.1109/ISIT.2013.6620500},
Key = {fds235776}
}

@article{fds235749,
Author = {Calderbank, R and Thompson, A and Xie, Y},
Title = {On block coherence of frames},
Journal = {Applied and Computational Harmonic Analysis},
Volume = {38},
Number = {1},
Pages = {50-71},
Year = {2014},
Month = {January},
ISSN = {1063-5203},
url = {http://dx.doi.org/10.1016/j.acha.2014.03.003},
of matrices plays an important role in analyzing the
performance of block compressed sensing recovery algorithmns
(Bajwa and Mixon, 2012). In this paper, we characterize two
block coheremice metrics: worst-case and average block
coherence. First, we present lower bounds on worst-case
block coherence, in both the general case and also when the
mnatrix is constrained to be a union of orthobases. We then
present determninistic mnatrix constructions based upon
Kronecker products which obtain these lower bounds. We also
characterize the worst-case block coherence of randomn
suibspaces. Finally, we present a flipping algorithmn that
can imnprove the average block coherence of a mnatrix, w}ule
mnaintaining the worst- case block coherence of the original
mnatrix. We provide nuimnerical examnples which demnonstrate
that our proposed determninistic mnatrix construction
performns well in block comnpressed sensing.},
Doi = {10.1016/j.acha.2014.03.003},
Key = {fds235749}
}

@article{fds235751,
Author = {Goparaju, S and El Rouayheb and S and Calderbank,
R},
Title = {New codes and inner bounds for exact repair in distributed
storage systems},
Journal = {IEEE International Symposium on Information Theory -
Proceedings},
Pages = {1036-1040},
Year = {2014},
Month = {January},
ISSN = {2157-8095},
url = {http://dx.doi.org/10.1109/ISIT.2014.6874990},
Abstract = {We study the exact-repair tradeoff between storage and
repair bandwidth in distributed storage systems. We give new
inner bounds for the tradeoff region and provide code
constructions that achieve these bounds. © 2014
IEEE.},
Doi = {10.1109/ISIT.2014.6874990},
Key = {fds235751}
}

@article{fds235752,
Author = {Nokleby, M and Rodrigues, M and Calderbank, R},
Title = {Discrimination on the grassmann manifold: Fundamental limits
of subspace classifiers},
Journal = {IEEE International Symposium on Information Theory -
Proceedings},
Pages = {3012-3016},
Year = {2014},
Month = {January},
ISSN = {2157-8095},
url = {http://dx.doi.org/10.1109/ISIT.2014.6875387},
Abstract = {Repurposing tools and intuitions from Shannon theory, we
derive fundamental limits on the reliable classification of
high-dimensional signals from low-dimensional features. We
focus on the classification of linear and affine subspaces
and suppose the features to be noisy linear projections.
Leveraging a syntactic equivalence of discrimination between
subspaces and communications over vector wireless channels,
we derive asymptotic bounds on classifier performance.
First, we define the classification capacity, which
characterizes necessary and sufficient relationships between
the signal dimension, the number of features, and the number
of classes to be discriminated, as all three quantities
approach infinity. Second, we define the
diversitydiscrimination tradeoff, which characterizes
relationships between the number of classes and the
misclassification probability as the signal-to-noise ratio
approaches infinity. We derive inner and outer bounds on
these measures, revealing precise relationships between
signal dimension and classifier performance. © 2014
IEEE.},
Doi = {10.1109/ISIT.2014.6875387},
Key = {fds235752}
}

@article{fds235753,
Author = {Goparaju, S and Calderbank, R},
Title = {Binary cyclic codes that are locally repairable},
Journal = {IEEE International Symposium on Information Theory -
Proceedings},
Pages = {676-680},
Year = {2014},
Month = {January},
ISSN = {2157-8095},
url = {http://dx.doi.org/10.1109/ISIT.2014.6874918},
Abstract = {Codes for storage systems aim to minimize the repair
locality, which is the number of disks (or nodes) that
participate in the repair of a single failed disk.
Simultaneously, the code must sustain a high rate, operate
on a small finite field to be practically significant and be
tolerant to a large number of erasures. To this end, we
construct new families of binary linear codes that have an
optimal dimension (rate) for a given minimum distance and
locality. Specifically, we construct cyclic codes that are
locally repairable for locality 2 and distances 2, 6 and 10.
In doing so, we discover new upper bounds on the code
dimension, and prove the optimality of enabling local repair
by provisioning disjoint groups of disks. Finally, we extend
our construction to build codes that have multiple repair
sets for each disk. © 2014 IEEE.},
Doi = {10.1109/ISIT.2014.6874918},
Key = {fds235753}
}

@article{fds235754,
Author = {Nokleby, M and Rodrigues, M and Calderbank, R},
Title = {Information-theoretic criteria for the design of compressive
subspace classifiers},
Journal = {IEEE International Conference on Acoustics Speech and Signal
Processing},
Pages = {3067-3071},
Year = {2014},
Month = {January},
ISSN = {1520-6149},
url = {http://dx.doi.org/10.1109/ICASSP.2014.6854164},
Abstract = {Using Shannon theory, we derive fundamental, asymptotic
limits on the classification of low-dimensional subspaces
from compressive measurements. We identify a syntactic
equivalence between the classification of subspaces and the
communication of codewords over non-coherent,
multiple-antenna channels, from which we derive sharp bounds
on the number of classes that can be discriminated with low
misclassification probability as a function of the signal
dimensionality and the signal-to-noise ratio. While the
bounds are asymptotic in the limit of high dimension, they
provide intuition for classifier design at finite dimension.
We validate this intuition via an application to face
recognition. © 2014 IEEE.},
Doi = {10.1109/ICASSP.2014.6854164},
Key = {fds235754}
}

@article{fds235755,
Author = {Carpenter, K and Sprechmann, P and Fiori, M and Calderbank, R and Egger,
H and Sapiro, G},
Title = {Questionnaire simplification for fast risk analysis of
children's mental health},
Journal = {IEEE International Conference on Acoustics Speech and Signal
Processing},
Pages = {6009-6013},
Year = {2014},
Month = {January},
ISSN = {1520-6149},
url = {http://dx.doi.org/10.1109/ICASSP.2014.6854757},
Abstract = {Early detection and treatment of psychiatric disorders on
children has shown significant impact in their subsequent
development and quality of life. The assessment of
psychopathology in childhood is commonly carried out by
performing long comprehensive interviews such as the widely
used Preschool Age Psychiatric Assessment (PAPA).
Unfortunately, the time required to complete a full
interview is too long to apply it at the scale of the actual
population at risk, and most of the population goes
undiagnosed or is diagnosed significantly later than
desired. In this work, we aim to learn from unique and very
rich previously collected PAPA examples the
inter-correlations between different questions in order to
provide a reliable risk analysis in the form of a much
shorter interview. This helps to put such important risk
analysis at the hands of regular practitioners, including
teachers and family doctors. We use for this purpose the
alternating decision trees algorithm, which combines
decision trees with boosting to produce small and
interpretable decision rules. Rather than a binary
prediction, the algorithm provides a measure of confidence
in the classification outcome. This is highly desirable from
a clinical perspective, where it is preferable to abstain a
decision on the low-confidence cases and recommend further
screening. In order to prevent over-fitting, we propose to
use network inference analysis to predefine a set of
candidate question with consistent high correlation with the
diagnosis. We report encouraging results with high levels of
prediction using two independently collected datasets. The
length and accuracy of the developed method suggests that it
could be a valuable tool for preliminary evaluation in
everyday care. © 2014 IEEE.},
Doi = {10.1109/ICASSP.2014.6854757},
Key = {fds235755}
}

@article{fds235756,
Author = {Goparaju, S and Rouayheb, SE and Calderbank, R},
Title = {New codes and inner bounds for exact repair in distributed
storage systems},
Journal = {2014 48th Annual Conference on Information Sciences and
Systems, CISS 2014},
Year = {2014},
Month = {January},
url = {http://dx.doi.org/10.1109/CISS.2014.6814148},
Abstract = {We study the exact-repair tradeoff between storage and
repair bandwidth in distributed storage systems (DSS). We
give new inner bounds for the tradeoff region and provide
code constructions that achieve these bounds. © 2014
IEEE.},
Doi = {10.1109/CISS.2014.6814148},
Key = {fds235756}
}

@article{fds235759,
Author = {Bennatan, A and Shamai, S and Calderbank, AR},
Title = {Soft-Decoding-Based Strategies for Relay and Interference
Channels: Analysis and Achievable Rates Using LDPC
Codes},
Journal = {IEEE Transactions on Information Theory},
Volume = {60},
Number = {4},
Pages = {1977-2009},
Year = {2014},
Month = {April},
ISSN = {0018-9448},
url = {http://dx.doi.org/10.1109/TIT.2013.2294373},
Doi = {10.1109/TIT.2013.2294373},
Key = {fds235759}
}

@article{fds235760,
Author = {Liming Wang, and Carlson, DE and Rodrigues, MRD and Calderbank, R and Carin, L},
Title = {A Bregman Matrix and the Gradient of Mutual Information for
Vector Poisson and Gaussian Channels},
Journal = {IEEE Transactions on Information Theory},
Volume = {60},
Number = {5},
Pages = {2611-2629},
Year = {2014},
Month = {May},
ISSN = {0018-9448},
url = {http://dx.doi.org/10.1109/TIT.2014.2307068},
Doi = {10.1109/TIT.2014.2307068},
Key = {fds235760}
}

@article{fds290773,
Author = {Wang, L and Huang, J and Yuan, X and Krishnamurthy, K and Greenberg, J and Cevher, V and Rodrigues, MRD and Brady, D and Calderbank, R and Carin,
L},
Title = {Signal Recovery and System Calibration from Multiple
Compressive Poisson Measurements},
Journal = {SIAM Journal on Imaging Sciences},
Volume = {8},
Number = {3},
Pages = {1923-1954},
Year = {2015},
Month = {January},
url = {http://dx.doi.org/10.1137/140998779},
Doi = {10.1137/140998779},
Key = {fds290773}
}

@article{fds235747,
Author = {Harms, A and Bajwa, WU and Calderbank, R},
Title = {Identification of Linear Time-Varying Systems Through
Waveform Diversity},
Journal = {IEEE Transactions on Signal Processing},
Volume = {63},
Number = {8},
Pages = {2070-2084},
Year = {2015},
Month = {April},
ISSN = {1053-587X},
url = {http://dx.doi.org/10.1109/TSP.2015.2407319},
Doi = {10.1109/TSP.2015.2407319},
Key = {fds235747}
}

@article{fds235748,
Author = {Nokleby, M and Rodrigues, M and Calderbank, R},
Title = {Discrimination on the Grassmann Manifold: Fundamental Limits
of Subspace Classifiers},
Journal = {IEEE Transactions on Information Theory},
Volume = {61},
Number = {4},
Pages = {2133-2147},
Year = {2015},
Month = {April},
ISSN = {0018-9448},
url = {http://dx.doi.org/10.1109/TIT.2015.2407368},
Doi = {10.1109/TIT.2015.2407368},
Key = {fds235748}
}

@article{fds235746,
Author = {Bajwa, WU and Duarte, MF and Calderbank, R},
Title = {Conditioning of Random Block Subdictionaries With
Applications to Block-Sparse Recovery and
Regression},
Journal = {IEEE Transactions on Information Theory},
Volume = {61},
Number = {7},
Pages = {4060-4079},
Year = {2015},
Month = {July},
ISSN = {0018-9448},
url = {http://dx.doi.org/10.1109/TIT.2015.2429632},
Doi = {10.1109/TIT.2015.2429632},
Key = {fds235746}
}

@article{fds326756,
Author = {Carpenter, KLH and Sprechmann, P and Calderbank, R and Sapiro, G and Egger, HL},
Title = {Quantifying Risk for Anxiety Disorders in Preschool
Children: A Machine Learning Approach.},
Journal = {PloS one},
Volume = {11},
Number = {11},
Pages = {e0165524},
Year = {2016},
Month = {January},
url = {http://dx.doi.org/10.1371/journal.pone.0165524},
Abstract = {Early childhood anxiety disorders are common, impairing, and
predictive of anxiety and mood disorders later in childhood.
Epidemiological studies over the last decade find that the
prevalence of impairing anxiety disorders in preschool
children ranges from 0.3% to 6.5%. Yet, less than 15% of
young children with an impairing anxiety disorder receive a
mental health evaluation or treatment. One possible reason
for the low rate of care for anxious preschoolers is the
lack of affordable, timely, reliable and valid tools for
identifying young children with clinically significant
anxiety. Diagnostic interviews assessing psychopathology in
young children require intensive training, take hours to
administer and code, and are not available for use outside
of research settings. The Preschool Age Psychiatric
Assessment (PAPA) is a reliable and valid structured
diagnostic parent-report interview for assessing
psychopathology, including anxiety disorders, in 2 to 5 year
old children. In this paper, we apply machine-learning tools
to already collected PAPA data from two large community
studies to identify sub-sets of PAPA items that could be
developed into an efficient, reliable, and valid screening
tool to assess a young child's risk for an anxiety disorder.
Using machine learning, we were able to decrease by an order
of magnitude the number of items needed to identify a child
who is at risk for an anxiety disorder with an accuracy of
over 96% for both generalized anxiety disorder (GAD) and
separation anxiety disorder (SAD). Additionally, rather than
considering GAD or SAD as discrete/binary entities, we
present a continuous risk score representing the child's
risk of meeting criteria for GAD or SAD. Identification of a
short question-set that assesses risk for an anxiety
disorder could be a first step toward development and
validation of a relatively short screening tool feasible for
use in pediatric clinics and daycare/preschool
settings.},
Doi = {10.1371/journal.pone.0165524},
Key = {fds326756}
}

@article{fds326890,
Author = {Huang, J and Qiu, Q and Calderbank, R},
Title = {The Role of Principal Angles in Subspace
Classification},
Journal = {IEEE Transactions on Signal Processing},
Volume = {64},
Number = {8},
Pages = {1933-1945},
Year = {2016},
Month = {April},
url = {http://dx.doi.org/10.1109/TSP.2015.2500889},
Doi = {10.1109/TSP.2015.2500889},
Key = {fds326890}
}

@article{fds326754,
Author = {Qiu, Q and Thompson, A and Calderbank, R and Sapiro,
G},
Title = {Data Representation Using the Weyl Transform},
Journal = {IEEE Transactions on Signal Processing},
Volume = {64},
Number = {7},
Pages = {1844-1853},
Year = {2016},
Month = {April},
url = {http://dx.doi.org/10.1109/TSP.2015.2505661},
Doi = {10.1109/TSP.2015.2505661},
Key = {fds326754}
}

@article{fds326887,
Author = {Sokolic, J and Renna, F and Calderbank, R and Rodrigues,
MRD},
Title = {Mismatch in the Classification of Linear Subspaces:
Sufficient Conditions for Reliable Classification},
Journal = {IEEE Transactions on Signal Processing},
Volume = {64},
Number = {12},
Pages = {3035-3050},
Year = {2016},
Month = {June},
url = {http://dx.doi.org/10.1109/TSP.2016.2537272},
Doi = {10.1109/TSP.2016.2537272},
Key = {fds326887}
}

@article{fds326884,
Author = {Vahid, A and Calderbank, R},
Title = {Two-User Erasure Interference Channels With Local Delayed
CSIT},
Journal = {IEEE Transactions on Information Theory},
Volume = {62},
Number = {9},
Pages = {4910-4923},
Year = {2016},
Month = {September},
url = {http://dx.doi.org/10.1109/TIT.2016.2594224},
Doi = {10.1109/TIT.2016.2594224},
Key = {fds326884}
}

@article{fds326883,
Author = {Thompson, A and Robles, FE and Wilson, JW and Deb, S and Calderbank, R and Warren, WS},
Title = {Dual-wavelength pump-probe microscopy analysis of melanin
composition.},
Journal = {Scientific Reports},
Volume = {6},
Pages = {36871},
Year = {2016},
Month = {November},
url = {http://dx.doi.org/10.1038/srep36871},
Abstract = {Pump-probe microscopy is an emerging technique that provides
detailed chemical information of absorbers with
sub-micrometer spatial resolution. Recent work has shown
that the pump-probe signals from melanin in human skin
cancers correlate well with clinical concern, but it has
been difficult to infer the molecular origins of these
differences. Here we develop a mathematical framework to
describe the pump-probe dynamics of melanin in human
pigmented tissue samples, which treats the ensemble of
individual chromophores that make up melanin as Gaussian
absorbers with bandwidth related via Frenkel excitons. Thus,
observed signals result from an interplay between the
spectral bandwidths of the individual underlying
chromophores and spectral proximity of the pump and probe
wavelengths. The model is tested using a dual-wavelength
pump-probe approach and a novel signal processing method
based on gnomonic projections. Results show signals can be
described by a single linear transition path with different
rates of progress for different individual pump-probe
wavelength pairs. Moreover, the combined dual-wavelength
data shows a nonlinear transition that supports our
mathematical framework and the excitonic model to describe
the optical properties of melanin. The novel gnomonic
projection analysis can also be an attractive generic tool
for analyzing mixing paths in biomolecular and analytical
chemistry.},
Doi = {10.1038/srep36871},
Key = {fds326883}
}

@article{fds326749,
Author = {Campbell, K and Carpenter, KLH and Espinosa, S and Hashemi, J and Qiu,
Q and Tepper, M and Calderbank, R and Sapiro, G and Egger, HL and Baker,
JP and Dawson, G},
Title = {Use of a Digital Modified Checklist for Autism in Toddlers -
Revised with Follow-up to Improve Quality of Screening for
Autism.},
Journal = {The Journal of Pediatrics},
Volume = {183},
Pages = {133-139.e1},
Year = {2017},
Month = {April},
url = {http://dx.doi.org/10.1016/j.jpeds.2017.01.021},
Abstract = {To assess changes in quality of care for children at risk
for autism spectrum disorders (ASD) due to process
improvement and implementation of a digital screening
form.The process of screening for ASD was studied in an
academic primary care pediatrics clinic before and after
implementation of a digital version of the Modified
Checklist for Autism in Toddlers - Revised with Follow-up
with automated risk assessment. Quality metrics included
accuracy of documentation of screening results and
appropriate action for positive screens (secondary screening
or referral). Participating physicians completed pre- and
postintervention surveys to measure changes in attitudes
toward feasibility and value of screening for ASD. Evidence
of change was evaluated with statistical process control
charts and χ2 tests.Accurate documentation in the
electronic health record of screening results increased from
54% to 92% (38% increase, 95% CI 14%-64%) and appropriate
action for children screening positive increased from 25% to
85% (60% increase, 95% CI 35%-85%). A total of 90% of
participating physicians agreed that the transition to a
digital screening form improved their clinical assessment of
autism risk.Implementation of a tablet-based digital version
of the Modified Checklist for Autism in Toddlers - Revised
with Follow-up led to improved quality of care for children
at risk for ASD and increased acceptability of screening for
ASD. Continued efforts towards improving the process of
screening for ASD could facilitate rapid, early diagnosis of
ASD and advance the accuracy of studies of the impact of
screening.},
Doi = {10.1016/j.jpeds.2017.01.021},
Key = {fds326749}
}

@article{fds326748,
Author = {Wang, L and Chen, M and Rodrigues, M and Wilcox, D and Calderbank, R and Carin, L},
Title = {Information-Theoretic Compressive Measurement
Design.},
Journal = {IEEE Transactions on Pattern Analysis and Machine
Intelligence},
Volume = {39},
Number = {6},
Pages = {1150-1164},
Year = {2017},
Month = {June},
url = {http://dx.doi.org/10.1109/tpami.2016.2568189},
Abstract = {An information-theoretic projection design framework is
proposed, of interest for feature design and compressive
measurements. Both Gaussian and Poisson measurement models
are considered. The gradient of a proposed
information-theoretic metric (ITM) is derived, and a
gradient-descent algorithm is applied in design; connections
are made to the information bottleneck. The fundamental
solution structure of such design is revealed in the case of
a Gaussian measurement model and arbitrary input statistics.
This new theoretical result reveals how ITM parameter
settings impact the number of needed projection
measurements, with this verified experimentally. The ITM
achieves promising results on real data, for both signal
recovery and classification.},
Doi = {10.1109/tpami.2016.2568189},
Key = {fds326748}
}

%% Conference articles PUBLISHED
@article{fds326908,
Author = {CALDERBANK, R and FISHBURN, P and SIEGEL, P},
Title = {STATE-SPACE CHARACTERIZATION OF VITERBI DETECTOR PATH METRIC
DIFFERENCES},
Journal = {CONFERENCE RECORD OF THE TWENTY-SIXTH ASILOMAR CONFERENCE ON
SIGNALS, SYSTEMS & COMPUTERS, VOLS 1 AND
2},
Pages = {940-944},
Year = {1992},
ISBN = {0-8186-3160-0},
Key = {fds326908}
}

@article{fds326907,
Author = {Naguib, AF and Calderbank, R},
Title = {Space-time coding and signal processing for high data rate
wireless communications},
Journal = {WIRELESS COMMUNICATION TECHNOLOGIES: NEW MULTIMEDIA
SYSTEMS},
Volume = {564},
Pages = {23-59},
Year = {2000},
ISBN = {0-7923-7900-4},
Key = {fds326907}
}

@article{fds235784,
Author = {Das, S and Al-Dhahir, N and Diggavi, S and Calderbank, R and IEEE},
Title = {Opportunistic space-time block codes},
Pages = {2025-2029},
Year = {2005},
ISBN = {0-7803-9152-7},
ISSN = {1090-3038},
Key = {fds235784}
}

@article{fds235785,
Author = {Calderbank, R and Das, S and Al-Dhahir, N and Diggavi, S and IEEE},
Title = {A novel full-rate full-diversity STBC with application to
WiMAX},
Pages = {1791-1795},
Year = {2005},
ISBN = {0-7803-9152-7},
ISSN = {1090-3038},
Key = {fds235785}
}

@article{fds322368,
Author = {Souvik, D and Thangaraj, A and McLaughlin, SW and Calderbank,
AR},
Title = {Linear-time decodable secrecy codes for binary erasure
wiretap channels},
Journal = {43rd Annual Allerton Conference on Communication, Control
and Computing 2005},
Volume = {3},
Pages = {1548-1556},
Year = {2005},
Month = {January},
ISBN = {9781604234916},
Abstract = {In this paper we consider encoder and decoder design for
codes achieving perfect secrecy on the wiretap channel. We
consider the special case of a noiseless main channel and
binary erasure channel (BEC) as the wiretapper's channel and
show that it is possible to construct linear-time decodable
secrecy codes based on LDPC codes that achieve perfect
secrecy.},
Key = {fds322368}
}

@article{fds322370,
Author = {Diggavi, S and Dusad, S and Calderbank, AR and Al-Dhahir,
N},
Title = {On embedded diversity codes},
Journal = {43rd Annual Allerton Conference on Communication, Control
and Computing 2005},
Volume = {2},
Pages = {1046-1055},
Year = {2005},
Month = {January},
ISBN = {9781604234916},
Abstract = {Diversity-embedded codes for fading channels are high-rate
codes that are de-signed so that they have a high-diversity
code embedded within them [3, 4]. This is equivalent to
coding the data into two streams such that the high-priority
stream has higher r eliability (designed in terms of
diversity order) than the low-priority stream. These codes
also allow a form of opportunistic communication where the
high-rate code opportunistically takes advantage of good
channel realizations whereas the embedded high-diversity
code ensures that at least part of the infor-mation is
received reliably. In this paper we give the design for a
class of such codes for a fixed transmit alphabet
constraint. These constructions are a natural generalization
of multilevel codes to diversity embedding. These codes give
prov-able performance guarantees by using binary matrices
with rank guarantees as the building blocks to generate the
desired diversity embedding in the complex do-main. We also
investigate the systems implications of these codes by
examining its applications to unequal error protection, rate
opportunism and packet delay optimization. Preliminary
results in these applications demonstrate that
diversity-embedded codes can outperform traditional
single-layer codes in moderate SNR regimes.},
Key = {fds322370}
}

@article{fds322369,
Author = {Ashikhmin, A and Calderbank, AR},
Title = {The first order space-time reed-muller codes},
Journal = {43rd Annual Allerton Conference on Communication, Control
and Computing 2005},
Volume = {2},
Pages = {1086-1095},
Year = {2005},
Month = {January},
ISBN = {9781604234916},
Abstract = {We present a family of Space-Time codes for the noncoherent
MIMO channel. These space-time codes are strongly related to
standard binary fist order Reed-Muller codes. In particular,
their decoder can be built from several parallel decoders of
first order Reed-Muller codes. We show that these codes
allow transmission with rates close to the MIMO noncoherent
unitary space-time codes capacity in the low signal to noise
ratio (SNR) regime.},
Key = {fds322369}
}

@article{fds326904,
Author = {Wu, Y and Calderbank, R and IEEE},
Title = {Code Diversity in Multiple Antenna Wireless
Communication},
Journal = {2008 IEEE INTERNATIONAL SYMPOSIUM ON INFORMATION THEORY
PROCEEDINGS, VOLS 1-6},
Pages = {1078-1082},
Year = {2008},
ISBN = {978-1-4244-2256-2},
url = {http://dx.doi.org/10.1109/ISIT.2008.4595153},
Doi = {10.1109/ISIT.2008.4595153},
Key = {fds326904}
}

@article{fds326901,
Author = {Zoltowski, MD and Qureshi, TR and Calderbank, R and IEEE},
Title = {Channel Estimation for MIMO-OFDM using Complementary
Codes},
Journal = {IEEE Radio and Wireless Symposium, RWS},
Pages = {151-+},
Year = {2009},
ISBN = {978-1-4244-2698-0},
Key = {fds326901}
}

@article{fds326902,
Author = {Calderbank, R and Howard, S and Jafarpour, S and IEEE},
Title = {A Sublinear Algorithm for Sparse Reconstruction with (2)
Recovery Guarantees},
Journal = {2009 3RD IEEE INTERNATIONAL WORKSHOP ON COMPUTATIONAL
(CAMSAP)},
Pages = {209-212},
Year = {2009},
Key = {fds326902}
}

@article{fds326903,
Author = {Chi, Y and Calderbank, R and Pezeshki, A and IEEE},
Title = {Golay Complementary Waveforms for Sparse Delay-Doppler Radar
Imaging},
Journal = {2009 3RD IEEE INTERNATIONAL WORKSHOP ON COMPUTATIONAL
(CAMSAP)},
Pages = {177-180},
Year = {2009},
Key = {fds326903}
}

@article{fds326899,
Author = {Harms, A and Bajwa, WU and Calderbank, R and IEEE},
Title = {Shaping the Power Spectra of Bipolar Sequences with
Application to Sub-Nyquist Sampling},
Journal = {2013 IEEE 5TH INTERNATIONAL WORKSHOP ON COMPUTATIONAL
2013)},
Pages = {236-+},
Year = {2013},
ISBN = {978-1-4673-3144-9},
Key = {fds326899}
}

@article{fds326900,
Author = {Harms, A and Bajwa, WU and Calderbank, R and IEEE},
Title = {Resource-Efficient Parametric Recovery of Linear
Time-Varying Systems},
Journal = {2013 IEEE 5TH INTERNATIONAL WORKSHOP ON COMPUTATIONAL
2013)},
Pages = {200-+},
Year = {2013},
ISBN = {978-1-4673-3144-9},
Key = {fds326900}
}

@article{fds235750,
Author = {Wang, L and Razi, A and Dias Rodrigues and M and Calderbank, R and Carin,
L},
Title = {Nonlinear information-theoretic compressive measurement
design},
Journal = {31st International Conference on Machine Learning, ICML
2014},
Volume = {4},
Pages = {2896-2907},
Year = {2014},
Month = {January},
ISBN = {9781634393973},
Abstract = {Copyright © (2014) by the International Machine Learning
general nonlinear functions for mapping high-dimensional
data into a lower-dimensional (compressive) space. The
nonlinear measurements are assumed contaminated by additive
Gaussian noise. Depending on the application, we are either
interested in recovering the high-dimensional data from the
nonlinear compressive measurements, or performing
classification directly based on these measurements. The
latter case corresponds to classification based on
nonlinearly constituted and noisy features. The nonlinear
measurement functions are designed based on constrained
mutual- information optimization. New analytic results are
developed for the gradient of mutual information in this
setting, for arbitrary input-signal statistics. We make
connections to kernel-based methods, such as the support
vector machine. Encouraging results are presented on
multiple datasets, for both signal recovery and
classification. The nonlinear approach is shown to be
particularly valuable in high-noise scenarios.},
Key = {fds235750}
}

@article{fds235744,
Author = {Harms, A and Bajwa, W and Calderbank, R},
Title = {Efficient linear time-varying system identification using
chirp waveforms},
Journal = {Conference Record of the Asilomar Conference on Signals,
Systems and Computers},
Volume = {2015-April},
Pages = {854-858},
Year = {2015},
Month = {January},
ISBN = {9781479982974},
ISSN = {1058-6393},
url = {http://dx.doi.org/10.1109/ACSSC.2014.7094572},
Abstract = {© 2014 IEEE. Linear, time-varying (LTV) systems are
operators composed of time shifts, frequency shifts, and
complex amplitude scalings that act on continuous
finite-energy waveforms. This paper builds upon a novel,
resource-efficient method previously proposed by the authors
for identifying the parametric description of such systems
from the sampled response to linear frequency modulated
(LFM) waveforms. If the LTV operator is probed with a
sufficiently diverse set of LFM pulses, more LFM pulses than
reflectors, then the system can be identified with high
accuracy. The accuracy is shown to be proportional to the
uncertainty in the estimated frequencies and confirmed with
numerical experiments.},
Doi = {10.1109/ACSSC.2014.7094572},
Key = {fds235744}
}

@article{fds322362,
Author = {Xian, Y and Thompson, A and Qiu, Q and Nolte, L and Nowacek, D and Lu, J and Calderbank, R},
Title = {Classification of whale vocalizations using the Weyl
transform},
Journal = {IEEE International Conference on Acoustics Speech and Signal
Processing},
Volume = {2015-August},
Pages = {773-777},
Year = {2015},
Month = {January},
ISBN = {9781467369978},
url = {http://dx.doi.org/10.1109/ICASSP.2015.7178074},
Abstract = {© 2015 IEEE. In this paper, we apply the Weyl transform to
represent the vocalization of marine mammals. In contrast to
other popular representation methods, such as the MFCC and
the Chirplet transform, the Weyl transform captures the
global information of signals. This is especially useful
when the signal has low order polynomial phase. We can
reconstruct the signal from the coefficients obtained from
the Weyl transform, and perform classification based on
these coefficients. Experimental results show that
classification using features extracted from the Weyl
transform outperforms the MFCC and the Chirplet transform on
our collected whales data.},
Doi = {10.1109/ICASSP.2015.7178074},
Key = {fds322362}
}

@article{fds322363,
Author = {Huang, J and Qiu, Q and Calderbank, R and Rodrigues, M and Sapiro,
G},
Title = {Alignment with intra-class structure can improve
classification},
Journal = {IEEE International Conference on Acoustics Speech and Signal
Processing},
Volume = {2015-August},
Pages = {1921-1925},
Year = {2015},
Month = {January},
ISBN = {9781467369978},
url = {http://dx.doi.org/10.1109/ICASSP.2015.7178305},
Abstract = {© 2015 IEEE. High dimensional data is modeled using
low-rank subspaces, and the probability of misclassification
is expressed in terms of the principal angles between
subspaces. The form taken by this expression motivates the
design of a new feature extraction method that enlarges
inter-class separation, while preserving intra-class
structure. The method can be tuned to emphasize different
features shared by members within the same class.
Classification performance is compared to that of
state-of-the-art methods on synthetic data and on the real
face database. The probability of misclassification is
decreased when intra-class structure is taken into
account.},
Doi = {10.1109/ICASSP.2015.7178305},
Key = {fds322363}
}

@article{fds322364,
Author = {Huang, J and Yuan, X and Calderbank, R},
Title = {Multi-scale Bayesian reconstruction of compressive X-ray
image},
Journal = {IEEE International Conference on Acoustics Speech and Signal
Processing},
Volume = {2015-August},
Pages = {1618-1622},
Year = {2015},
Month = {January},
ISBN = {9781467369978},
url = {http://dx.doi.org/10.1109/ICASSP.2015.7178244},
Abstract = {© 2015 IEEE. A novel multi-scale dictionary based Bayesian
reconstruction algorithm is proposed for compressive X-ray
imaging, which encodes the material's spectrum by Poisson
measurements. Inspired by recently developed compressive
X-ray imaging systems [1], this work aims to recover the
material's spectru m from the compressive coded image by
leveraging a reference spectrum library. Instead of directly
using the huge and redundant library as a dictionary, which
is cumbersome in computation and difficult for selecting
those active dictionary atoms, a multi-scale tree structured
dictionary is refined from the spectrum library, and
following this a Bayesian reconstruction algorithm is
developed. Experimental results on real data demonstrate
superior performance in comparison with traditional
methods.},
Doi = {10.1109/ICASSP.2015.7178244},
Key = {fds322364}
}

@article{fds322365,
Author = {Yuan, X and Huang, J and Calderbank, R},
Title = {Polynomial-phase signal direction-finding and
source-tracking with a single acoustic vector
sensor},
Journal = {IEEE International Conference on Acoustics Speech and Signal
Processing},
Volume = {2015-August},
Pages = {2559-2563},
Year = {2015},
Month = {January},
ISBN = {9781467369978},
url = {http://dx.doi.org/10.1109/ICASSP.2015.7178433},
Abstract = {© 2015 IEEE. This paper introduces a new ESPRIT-based
algorithm to estimate the direction-of-arrival of an
arbitrary degree polynomial-phase signal with a single
acoustic vector-sensor. The proposed time-invariant ESPRIT
algorithm is based on a matrix-pencil pair derived from the
time-delayed data-sets collected by a single acoustic
vector-sensor. This approach requires neither a prior
knowledge of the polynomial-phase signal's coefficients nor
a prior knowledge of the polynomial-phase signal's
frequency-spectrum. Furthermore, a preprocessing technique
is proposed to incorporate the single-forgetting-factor
algorithm and multiple-forgetting-factor adaptive tracking
algorithm to track a polynomial-phase signal using one
acoustic vector sensor. Simulation results verify the
efficacy of the proposed direction finding and source
tracking algorithms.},
Doi = {10.1109/ICASSP.2015.7178433},
Key = {fds322365}
}

@article{fds322366,
Author = {Huang, J and Yuan, X and Calderbank, R},
Title = {Collaborative compressive X-ray image reconstruction},
Journal = {IEEE International Conference on Acoustics Speech and Signal
Processing},
Volume = {2015-August},
Pages = {3282-3286},
Year = {2015},
Month = {January},
ISBN = {9781467369978},
url = {http://dx.doi.org/10.1109/ICASSP.2015.7178578},
Abstract = {© 2015 IEEE. The Poisson Factor Analysis (PFA) is applied
to recover signals from a Poisson compressive sensing
system. Motivated by the recently developed compressive
X-ray imaging system, Coded Aperture Coherent Scatter
Spectral Imaging (CACSSI) [1], we propose a new Bayesian
reconstruction algorithm. The proposed Poisson-Gamma (PG)
approach uses multiple measurements to refine our knowledge
on both sensing matrix and b ackground noise to overcome the
uncertainties and inaccuracy of the hardware system.
Therefore, a collaborative compressive X-ray image
reconstruction algorithm is proposed under a Bayesian
framework. Experimental results on real data show
competitive performance in comparison with point estimation
based methods.},
Doi = {10.1109/ICASSP.2015.7178578},
Key = {fds322366}
}

@article{fds326898,
Author = {Michelusi, N and Nokleby, M and Mitra, U and Calderbank,
R},
Title = {Dynamic spectrum estimation with minimal overhead via
multiscale information exchange},
Journal = {2015 IEEE Global Communications Conference, GLOBECOM
2015},
Year = {2015},
Month = {January},
ISBN = {9781479959525},
url = {http://dx.doi.org/10.1109/GLOCOM.2014.7417532},
Abstract = {© 2015 IEEE. In this paper, a multiscale approach to
spectrum sensing in cognitive cellular networks is analyzed.
Observing that wireless interference decays with distance,
and that estimating the entire spectrum occupancy across the
network entails substantial energy cost and communication
overhead, a protocol for distributed spectrum estimation is
defined by which secondary users maintain fine-grained
estimates of the spectrum occupancy of nearby cells, but
coarse-grained estimates of that of distant cells. This is
accomplished by arranging the cellular network into a
hierarchy of increasingly coarser macro-cells and having
secondary users fuse local spectrum estimates up the
hierarchy. The spectrum occupancy is modeled as a Markov
process, and the system is optimized by defining a
probabilistic framework for spectrum sensing and information
exchange that balances improvements in spectrum estimation
against energy costs. The performance of the multiscale
scheme is evaluated numerically, showing that it offers
substantial improvements in energy efficiency over local
estimation. On the other hand, it is shown that schemes that
attempt to estimate the state of the whole network perform
poorly, due to the excessive cost of performing information
exchange with far away cells, and to the fact that, knowing
the spectrum occupancy of distant cells, which experience
low interference levels, results in a small increase in
reward.},
Doi = {10.1109/GLOCOM.2014.7417532},
Key = {fds326898}
}

@article{fds326755,
Author = {Huang, J and Qiu, Q and Calderbank, R and Sapiro,
G},
Title = {Geometry-aware deep transform},
Journal = {Proceedings / IEEE International Conference on Computer
Vision. IEEE International Conference on Computer
Vision},
Volume = {2015 International Conference on Compute},
Pages = {4139-4147},
Year = {2015},
Month = {February},
ISBN = {9781467383912},
url = {http://dx.doi.org/10.1109/ICCV.2015.471},
Abstract = {© 2015 IEEE. Many recent efforts have been devoted to
designing sophisticated deep learning structures, obtaining
revolutionary results on benchmark datasets. The success of
these deep learning methods mostly relies on an enormous
volume of labeled training samples to learn a huge number of
parameters in a network, therefore, understanding the
generalization ability of a learned deep network cannot be
overlooked, especially when restricted to a small training
set, which is the case for many applications. In this paper,
we propose a novel deep learning objective formulation that
unifies both the classification and metric learning
criteria. We then introduce a geometry-aware deep transform
to enable a non-linear discriminative and robust feature
transform, which shows competitive performance on small
training sets for both synthetic and real-world data. We
further support the proposed framework with a formal
(K)-robustness analysis.},
Doi = {10.1109/ICCV.2015.471},
Key = {fds326755}
}

@article{fds326894,
Author = {Vahid, A and Calderbank, R},
Title = {Impact of local delayed CSIT on the capacity region of the
two-user interference channel},
Journal = {IEEE International Symposium on Information Theory -
Proceedings},
Volume = {2015-June},
Pages = {2421-2425},
Year = {2015},
Month = {September},
ISBN = {9781467377041},
url = {http://dx.doi.org/10.1109/ISIT.2015.7282890},
Abstract = {© 2015 IEEE. The coherence time of a wireless channel is
often smaller than the delay with which channel state
information is available at transmitters. In this paper, we
aim to find the most important subset of the channel state
information that transmitters need to learn with delay. We
characterize the capacity region of the two-user
interference channel with local delayed channel state
information at transmitters. We propose a transmission
strategy that only relies on the delayed knowledge of the
outgoing links at each transmitter and achieves the
outer-bound for the scenario in which transmitters learn the
entire channel state with delay. We also show that the
delayed knowledge of the outgoing links is the minimum
delayed knowledge that is required to outperform the no
knowledge assumption.},
Doi = {10.1109/ISIT.2015.7282890},
Key = {fds326894}
}

@article{fds326895,
Author = {Sokolić, J and Renna, F and Calderbank, R and Rodrigues,
MRD},
Title = {Mismatch in the classification of linear subspaces: Upper
bound to the probability of error},
Journal = {IEEE International Symposium on Information Theory -
Proceedings},
Volume = {2015-June},
Pages = {2201-2205},
Year = {2015},
Month = {September},
ISBN = {9781467377041},
url = {http://dx.doi.org/10.1109/ISIT.2015.7282846},
Abstract = {© 2015 IEEE. This paper studies the performance associated
with the classification of linear subspaces corrupted by
noise with a mismatched classifier. In particular, we
consider a problem where the classifier observes a noisy
signal, the signal distribution conditioned on the signal
class is zero-mean Gaussian with low-rank covariance matrix,
and the classifier knows only the mismatched parameters in
lieu of the true parameters. We derive an upper bound to the
misclassification probability of the mismatched classifier
and characterize its behaviour. Specifically, our
characterization leads to sharp sufficient conditions that
describe the absence of an error floor in the low-noise
regime, and that can be expressed in terms of the principal
angles and the overlap between the true and the mismatched
signal subspaces.},
Doi = {10.1109/ISIT.2015.7282846},
Key = {fds326895}
}

@article{fds326896,
Author = {Beirami, A and Calderbank, R and Duffy, K and Medard,
M},
Title = {Quantifying computational security subject to source
constraints, guesswork and inscrutability},
Journal = {IEEE International Symposium on Information Theory -
Proceedings},
Volume = {2015-June},
Pages = {2757-2761},
Year = {2015},
Month = {September},
ISBN = {9781467377041},
url = {http://dx.doi.org/10.1109/ISIT.2015.7282958},
Abstract = {© 2015 IEEE. Guesswork forms the mathematical framework for
quantifying computational security subject to brute-force
determination by query. In this paper, we consider guesswork
subject to a per-symbol Shannon entropy budget. We introduce
inscrutability rate as the asymptotic rate of increase in
the exponential number of guesses required of an adversary
to determine one or more secret strings. We prove that the
inscrutability rate of any string-source supported on a
finite alphabet χ, if it exists, lies between the
per-symbol Shannon entropy constraint and log χ. We further
prove that the inscrutability rate of any finite-order
Markov string-source with hidden statistics remains the same
as the unhidden case, i.e., the asymptotic value of hiding
the statistics per each symbol is vanishing. On the other
hand, we show that there exists a string-source that
achieves the upper limit on the inscrutability rate, i.e.,
log χ, under the same Shannon entropy budget.},
Doi = {10.1109/ISIT.2015.7282958},
Key = {fds326896}
}

@article{fds326897,
Author = {Tamo, I and Barg, A and Goparaju, S and Calderbank,
R},
Title = {Cyclic LRC codes and their subfield subcodes},
Journal = {IEEE International Symposium on Information Theory -
Proceedings},
Volume = {2015-June},
Pages = {1262-1266},
Year = {2015},
Month = {September},
ISBN = {9781467377041},
url = {http://dx.doi.org/10.1109/ISIT.2015.7282658},
Abstract = {© 2015 IEEE. We consider linear cyclic codes with the
locality property, or locally recoverable codes (LRC codes).
A family of LRC codes that generalizes the classical
construction of Reed-Solomon codes was constructed in a
recent paper by I. Tamo and A. Barg (IEEE Trans. IT, no. 8,
2014). In this paper we focus on the optimal cyclic codes
that arise from the general construction. We give a
characterization of these codes in terms of their zeros, and
observe that there are many equivalent ways of constructing
optimal cyclic LRC codes over a given field. We also study
subfield subcodes of cyclic LRC codes (BCH-like LRC codes)
and establish several results about their locality and
minimum distance.},
Doi = {10.1109/ISIT.2015.7282658},
Key = {fds326897}
}

@article{fds326758,
Author = {Renna, F and Wang, L and Yuan, X and Yang, J and Reeves, G and Calderbank,
R and Carin, L and Rodrigues, MRD},
Title = {Classification and reconstruction of compressed GMM signals
with side information},
Journal = {IEEE International Symposium on Information Theory -
Proceedings},
Volume = {2015-June},
Pages = {994-998},
Year = {2015},
Month = {September},
ISBN = {9781467377041},
url = {http://dx.doi.org/10.1109/ISIT.2015.7282604},
Abstract = {© 2015 IEEE. This paper offers a characterization of
performance limits for classification and reconstruction of
high-dimensional signals from noisy compressive
measurements, in the presence of side information. We assume
the signal of interest and the side information signal are
drawn from a correlated mixture of distributions/components,
where each component associated with a specific class label
follows a Gaussian mixture model (GMM). We provide sharp
sufficient and/or necessary conditions for the phase
transition of the misclassification probability and the
reconstruction error in the low-noise regime. These
conditions, which are reminiscent of the well-known
Slepian-Wolf and Wyner-Ziv conditions, are a function of the
number of measurements taken from the signal of interest,
the number of measurements taken from the side information
signal, and the geometry of these signals and their
interplay.},
Doi = {10.1109/ISIT.2015.7282604},
Key = {fds326758}
}

@article{fds326757,
Author = {Eslami, A and Velasco, A and Vahid, A and Mappouras, G and Calderbank,
R and Sorin, DJ},
Title = {Writing without disturb on phase change memories by
integrating coding and layout design},
Journal = {ACM International Conference Proceeding Series},
Volume = {05-08-October-2015},
Pages = {71-77},
Year = {2015},
Month = {October},
ISBN = {9781450336048},
url = {http://dx.doi.org/10.1145/2818950.2818962},
Abstract = {© 2015 ACM. We integrate coding techniques and layout
design to elimi- nate write-disturb in phase change memories
(PCMs), while enhancing lifetime and host-visible capacity.
We first pro- pose a checkerboard confguration for cell
layout to elimi- nate write-disturb while doubling the
memory lifetime. We then introduce two methods to jointly
design Write-Once- Memory (WOM) codes and layout. The first
WOM-layout design improves the lifetime by more than double
without compromising the host-visible capacity. The second
design applies WOM codes to even more dense layouts to
achieve both lifetime and capacity gains. The constructions
demon- strate that substantial improvements to lifetime and
host- visible capacity are possible by co-designing coding
and cell layout in PCM.},
Doi = {10.1145/2818950.2818962},
Key = {fds326757}
}

@article{fds326893,
Author = {Nokleby, M and Beirami, A and Calderbank, R},
Title = {A rate-distortion framework for supervised
learning},
Journal = {IEEE International Workshop on Machine Learning for Signal
Processing : [proceedings]. IEEE International Workshop on
Machine Learning for Signal Processing},
Volume = {2015-November},
Year = {2015},
Month = {November},
ISBN = {9781467374545},
url = {http://dx.doi.org/10.1109/MLSP.2015.7324319},
Abstract = {© 2015 IEEE. An information-theoretic framework is
presented for bounding the number of samples needed for
supervised learning in a parametric Bayesian setting. This
framework is inspired by an analogy with rate-distortion
theory, which characterizes tradeoffs in the lossy
compression of random sources. In a parametric Bayesian
environment, the maximum a posteriori classifier can be
viewed as a random function of the model parameters. Labeled
training data can be viewed as a finite-rate encoding of
that source, and the excess loss due to using the learned
classifier instead of the MAP classifier can be viewed as
distortion. A strict bound on the loss-measured in terms of
the expected total variation-is derived, providing a minimum
number of training samples needed to drive the expected
total variation to within a specified tolerance. The
tightness of this bound is demonstrated on the
classification of Gaus-sians, for which one can derive
closed-form expressions for the bound.},
Doi = {10.1109/MLSP.2015.7324319},
Key = {fds326893}
}

@article{fds326892,
Author = {Thompson, A and Calderbank, R},
Title = {Compressive imaging using fast transform
coding},
Journal = {Proceedings of SPIE - The International Society for Optical
Engineering},
Volume = {9992},
Year = {2016},
Month = {January},
ISBN = {9781510603882},
url = {http://dx.doi.org/10.1117/12.2239999},
Abstract = {© 2016 SPIE. We propose deterministic sampling strategies
for compressive imaging based on Delsarte-Goethals frames.
We show that these sampling strategies result in multi-scale
measurements which can be related to the 2D Haar wavelet
transform. We demonstrate the effectiveness of our proposed
strategies through numerical experiments.},
Doi = {10.1117/12.2239999},
Key = {fds326892}
}

@article{fds326891,
Author = {Goparaju, S and Rouayheb, SE and Calderbank, R},
Title = {Can linear minimum storage regenerating codes be universally
secure?},
Journal = {Conference Record of the Asilomar Conference on Signals,
Systems and Computers},
Volume = {2016-February},
Pages = {549-553},
Year = {2016},
Month = {February},
ISBN = {9781467385763},
url = {http://dx.doi.org/10.1109/ACSSC.2015.7421189},
Abstract = {© 2015 IEEE. We study the problem of making a distributed
storage system information-theoretically secure against a
passive eavesdropper, and aim to characterize coding schemes
that are universally secure for up to a given number of
eavesdropped nodes. Specifically, we consider minimum
storage regenerating (MSR) codes and ask the following
question: For an MSR code where a failed node is repaired
using all the remaining nodes, is it possible to
simultaneously be optimally secure using a single linear
coding scheme? We define a pareto-optimality associated with
this simultaneity and show that there exists at least one
linear coding scheme that is pareto-optimal.},
Doi = {10.1109/ACSSC.2015.7421189},
Key = {fds326891}
}

@article{fds326888,
Author = {Beirami, A and Calderbank, R and Christiansen, M and Duffy, K and Makhdoumi, A and Medard, M},
Title = {A geometric perspective on guesswork},
Journal = {2015 53rd Annual Allerton Conference on Communication,
Control, and Computing, Allerton 2015},
Pages = {941-948},
Year = {2016},
Month = {April},
ISBN = {9781509018239},
url = {http://dx.doi.org/10.1109/ALLERTON.2015.7447109},
Abstract = {© 2015 IEEE. Guesswork is the position at which a random
string drawn from a given probability distribution appears
in the list of strings ordered from the most likely to the
least likely. We define the tilt operation on probability
distributions and show that it parametrizes an exponential
family of distributions, which we refer to as the tilted
family of the source. We prove that two sources result in
the same guesswork, i.e., the same ordering from most likely
to least likely on all strings, if and only if they belong
to the same tilted family. We also prove that the strings
whose guesswork is smaller than a given string are
concentrated on the tilted family. Applying Laplace's
method, we derive precise approximations on the distribution
of guesswork on i.i.d. sources. The simulations show a good
match between the approximations and the actual guesswork
for i.i.d. sources.},
Doi = {10.1109/ALLERTON.2015.7447109},
Key = {fds326888}
}

@article{fds326889,
Author = {Vahid, A and Shomorony, I and Calderbank, R},
Title = {Informational bottlenecks in two-unicast wireless networks
with delayed CSIT},
Journal = {2015 53rd Annual Allerton Conference on Communication,
Control, and Computing, Allerton 2015},
Pages = {1256-1263},
Year = {2016},
Month = {April},
ISBN = {9781509018239},
url = {http://dx.doi.org/10.1109/ALLERTON.2015.7447152},
Abstract = {© 2015 IEEE. We study the impact of delayed channel state
information at the transmitters (CSIT) in two-unicast
wireless networks with a layered topology and arbitrary
connectivity. We introduce a technique to obtain outer
bounds to the degrees-of-freedom (DoF) region through the
new graph-theoretic notion of bottleneck nodes. Such nodes
act as informational bottlenecks only under the assumption
of delayed CSIT, and imply asymmetric DoF bounds of the form
mD1 + D2 ≤ m. Combining this outer-bound technique with
new achievability schemes, we characterize the sum DoF of a
class of two-unicast wireless networks, which shows that,
unlike in the case of instantaneous CSIT, the DoF of
two-unicast networks with delayed CSIT can take an infinite
set of values.},
Doi = {10.1109/ALLERTON.2015.7447152},
Key = {fds326889}
}

@article{fds326753,
Author = {Wang, L and Renna, F and Yuan, X and Rodrigues, M and Calderbank, R and Carin, L},
Title = {A general framework for reconstruction and classification
from compressive measurements with side information},
Journal = {IEEE International Conference on Acoustics Speech and Signal
Processing},
Volume = {2016-May},
Pages = {4239-4243},
Year = {2016},
Month = {May},
ISBN = {9781479999880},
url = {http://dx.doi.org/10.1109/ICASSP.2016.7472476},
Abstract = {© 2016 IEEE. We develop a general framework for compressive
linear-projection measurements with side information. Side
information is an additional signal correlated with the
signal of interest. We investigate the impact of side
information on classification and signal recovery from
low-dimensional measurements. Motivated by real
applications, two special cases of the general model are
studied. In the first, a joint Gaussian mixture model is
manifested on the signal and side information. The second
example again employs a Gaussian mixture model for the
signal, with side information drawn from a mixture in the
exponential family. Theoretical results on recovery and
classification accuracy are derived. The presence of side
information is shown to yield improved performance, both
theoretically and experimentally.},
Doi = {10.1109/ICASSP.2016.7472476},
Key = {fds326753}
}

@article{fds326885,
Author = {Nokleby, M and Beirami, A and Calderbank, R},
Title = {Rate-distortion bounds on Bayes risk in supervised
learning},
Journal = {IEEE International Symposium on Information Theory -
Proceedings},
Volume = {2016-August},
Pages = {2099-2103},
Year = {2016},
Month = {August},
ISBN = {9781509018062},
url = {http://dx.doi.org/10.1109/ISIT.2016.7541669},
Abstract = {© 2016 IEEE. An information-theoretic framework is
presented for estimating the number of labeled samples
needed to train a classifier in a parametric Bayesian
setting. Ideas from rate-distortion theory are used to
derive bounds for the average L 1 or L ∞ distance between
the learned classifier and the true maximum a posteriori
classifier in terms of familiar information-theoretic
quantities and the number of training samples available. The
maximum a posteriori classifier is viewed as a random
source, labeled training data are viewed as a finite-rate
encoding of the source, and the L 1 or L ∞ Bayes risk is
viewed as the average distortion. The result is a framework
dual to the well-known probably approximately correct (PAC)
framework. PAC bounds characterize worst-case learning
performance of a family of classifiers whose complexity is
captured by the Vapnik-Chervonenkis (VC) dimension. The
rate-distortion framework, on the other hand, characterizes
the average-case performance of a family of data
distributions in terms of a quantity called the
interpolation dimension, which represents the complexity of
the family of data distributions. The resulting bounds do
not suffer from the pessimism typical of the PAC framework,
particularly when the training set is small.},
Doi = {10.1109/ISIT.2016.7541669},
Key = {fds326885}
}

@article{fds326886,
Author = {Vahid, A and Calderbank, R},
Title = {When does spatial correlation add value to delayed channel
state information?},
Journal = {IEEE International Symposium on Information Theory -
Proceedings},
Volume = {2016-August},
Pages = {2624-2628},
Year = {2016},
Month = {August},
ISBN = {9781509018062},
url = {http://dx.doi.org/10.1109/ISIT.2016.7541774},
Abstract = {© 2016 IEEE. Fast fading wireless networks with delayed
knowledge of the channel state information have received
significant attention in recent years. An exception is
networks where channels are spatially correlated. This paper
characterizes the capacity region of two-user erasure
interference channels with delayed knowledge of the channel
state information and spatially correlated channels. There
are instances where spatial correlation eliminates any
potential gain from delayed channel state information and
instances where it enables the same performance that is
possible with instantaneous knowledge of channel state. The
key is an extremal entropy inequality for spatially
correlated channels that separates the two types of
instances. It is also shown that to achieve the capacity
region, each transmitter only needs to rely on the delayed
knowledge of the channels to which it is
connected.},
Doi = {10.1109/ISIT.2016.7541774},
Key = {fds326886}
}

@article{fds326752,
Author = {Mappouras, G and Vahid, A and Calderbank, R and Sorin,
DJ},
Title = {Methuselah flash: Rewriting codes for extra long storage
Journal = {Proceedings - 46th Annual IEEE/IFIP International Conference
on Dependable Systems and Networks, DSN 2016},
Pages = {180-191},
Year = {2016},
Month = {September},
ISBN = {9781467388917},
url = {http://dx.doi.org/10.1109/DSN.2016.25},
Abstract = {© 2016 IEEE. Motivated by embedded systems and datacenters
that require long-life components, we extend the lifetime of
Flash memory using rewriting codes that allow for multiple
writes to a page before it needs to be erased. Although
researchers have previously explored rewriting codes for
this purpose, we make two significant contributions beyond
prior work. First, we remove the assumption of idealized -
and unrealistically optimistic - Flash cells used in prior
work on endurance codes. Unfortunately, current Flash
technology has a non-ideal interface, due to its underlying
physical design, and does not, for example, allow all
seemingly possible increases in a cell's level. We show how
to provide the ideal multi-level cell interface, by
developing a virtual Flash cell, and we evaluate its impact
on existing endurance codes. Our second contribution is our
development of novel endurance codes, called Methuselah
Flash Codes (MFC), that provide better cost/lifetime
trade-offs than previously studied codes.},
Doi = {10.1109/DSN.2016.25},
Key = {fds326752}
}

@article{fds326751,
Author = {Kumar, S and Calderbank, R and Pfister, HD},
Title = {Beyond double transitivity: Capacity-achieving cyclic codes
on erasure channels},
Journal = {2016 IEEE Information Theory Workshop, ITW
2016},
Pages = {241-245},
Year = {2016},
Month = {October},
ISBN = {9781509010905},
url = {http://dx.doi.org/10.1109/ITW.2016.7606832},
Abstract = {© 2016 IEEE. Recently, sequences of error-correcting codes
with doubly-transitive permutation groups were shown to
achieve capacity on erasure channels under symbol-wise
maximum a posteriori (MAP) decoding. From this, it follows
that Reed-Muller and primitive narrow-sense BCH codes
achieve capacity in the same setting. In this article, we
extend this result to a large family of cyclic codes by
considering codes whose permutation groups satisfy a
condition weaker than double transitivity. The article
combines two simple technical contributions. First, we show
that the transition width of a monotone boolean function is
O(1/log k), where k is the size of the smallest orbit
induced by its symmetry group. The proof is based on
Talagrand's lower bound on influences for monotone boolean
functions. Second, we consider the extrinsic information
transfer (EXIT) function of an Fq-linear cyclic code whose
blocklength N divides q t -1 and is coprime with q-1. We
show that this EXIT function is a monotone boolean function
whose symmetry group contains no orbits of size smaller than
the smallest prime divisor of t. Combining these, we show
that sequences of cyclic codes, whose blocklengths satisfy
the above conditions, achieve capacity on the q-ary erasure
channel if all prime divisors of t tend to
infinity.},
Doi = {10.1109/ITW.2016.7606832},
Key = {fds326751}
}

@article{fds326750,
Author = {Renna, F and Wang, L and Yuan, X and Yang, J and Reeves, G and Calderbank,
R and Carin, L and Rodrigues, MRD},
Title = {Classification and Reconstruction of High-Dimensional
Signals From Low-Dimensional Features in the Presence of
Side Information},
Journal = {IEEE Transactions on Information Theory},
Volume = {62},
Number = {11},
Pages = {6459-6492},
Year = {2016},
Month = {November},
url = {http://dx.doi.org/10.1109/TIT.2016.2606646},
Doi = {10.1109/TIT.2016.2606646},
Key = {fds326750}
}

@article{fds326882,
Author = {Reboredo, H and Renna, F and Calderbank, R and Rodrigues,
MRD},
Title = {Bounds on the Number of Measurements for Reliable
Compressive Classification},
Journal = {IEEE Transactions on Signal Processing},
Volume = {64},
Number = {22},
Pages = {5778-5793},
Year = {2016},
Month = {November},
url = {http://dx.doi.org/10.1109/TSP.2016.2599496},
Doi = {10.1109/TSP.2016.2599496},
Key = {fds326882}
}

@article{fds326881,
Author = {Hadani, R and Rakib, S and Tsatsanis, M and Monk, A and Goldsmith, AJ and Molisch, AF and Calderbank, R},
Title = {Orthogonal time frequency space modulation},
Journal = {IEEE Wireless Communications and Networking
Conference},
Year = {2017},
Month = {May},
ISBN = {9781509041831},
url = {http://dx.doi.org/10.1109/WCNC.2017.7925924},
Abstract = {© 2017 IEEE. A new two-dimensional modulation technique
called Orthogonal Time Frequency Space (OTFS) modulation
designed in the delay-Doppler domain is introduced. Through
this design, which exploits full diversity over time and
frequency, OTFS coupled with equalization converts the
fading, time-varying wireless channel experienced by
modulated signals such as OFDM into a time-independent
channel with a complex channel gain that is roughly constant
for all symbols. Thus, transmitter adaptation is not needed.
This extraction of the full channel diversity allows OTFS to
greatly simplify system operation and significantly improves
performance, particular in systems with high Doppler, short
packets, and large antenna arrays. Simulation results
indicate at least several dB of block error rate performance
improvement for OTFS over OFDM in all of these settings. In
addition these results show that even at very high Dopplers
(500 km/h), OTFS approaches channel capacity through linear
scaling of throughput with the MIMO order, whereas the
performance of OFDM under typical design parameters breaks
down completely.},
Doi = {10.1109/WCNC.2017.7925924},
Key = {fds326881}
}