List-message passing achieves capacity on the q-ary symmetric channel for large q


Conference Paper

We discuss and analyze a list-message-passing decoder with verification for low-density parity-check (LDPC) codes on the q-ary symmetric channel (q-SC). Rather than passing messages consisting of symbol probabilities, we pass lists of possible symbols and mark very likely symbols as verified. The density evolution (DE) equations for this decoder are derived and used to compute decoding thresholds. If the maximum list-size is unbounded, then we find that any capacity-achieving LDPC code for the binary erasure channel can be used to achieve capacity on the q-SC for large q. The decoding thresholds are also computed via DE for the case where each list is truncated to satisfy a maximum list-size constraint. The probability of false verification is considered for this case, and techniques are discussed to mitigate the problem. Optimization of the degree distribution is also used to improve the threshold for a fixed maximum list size. Finally, the proposed algorithm is compared with a variety of other algorithms using both density evolution thresholds and simulation results. © 2007 IEEE.

Full Text

Duke Authors

Cited Authors

  • Fan, Z; Pfister, HD

Published Date

  • December 1, 2007

Published In

  • Globecom Ieee Global Telecommunications Conference

Start / End Page

  • 283 - 287

International Standard Book Number 10 (ISBN-10)

  • 1424410436

International Standard Book Number 13 (ISBN-13)

  • 9781424410439

Digital Object Identifier (DOI)

  • 10.1109/GLOCOM.2007.60

Citation Source

  • Scopus