Publications [#384479] of Robert Calderbank

Papers Published

1. Dabak, B; Tiryaki, E; Calderbank, R; Hareedy, A, LDPC Decoders Prefer More Reliable Parity Bits: Unequal Data Protection Over BSC, 2023 12th International Symposium on Topics in Coding Istc 2023 (January, 2023) [doi]
   (last updated on 2026/01/16)

   Abstract:
   Low-density parity-check (LDPC) codes are specified by graphs, and are the error correction technique of choice in many communications and data storage contexts. Message passing decoders diffuse information carried by parity bits into the payload, and this paper measures the value of engineering parity bits to be more reliable than message bits. We consider the binary symmetric channel (BSC) and measure the impact of unequal data protection on the threshold of a regular LDPC code. Our analysis also includes doping where the parity bits are known to the decoder. We investigate BSC with Gallager-A decoder, with a 3-1evel-alphabet decoder, and with a full belief propagation decoder. We demonstrate through theoretical analysis and simulation that non-equiprobable inputs lead to significant improvements both in the threshold and in the speed with which the decoder converges. We also show that all these improvements are possible even with a simple 3-1evel-alphabet decoder.