Title
Improved low-density parity-check codes using irregular graphs
Abstract
We construct new families of error-correcting codes based on Gallager's (1973) low-density parity-check codes. We improve on Gallager's results by introducing irregular parity-check matrices and a new rigorous analysis of hard-decision decoding of these codes. We also provide efficient methods for finding good irregular structures for such decoding algorithms. Our rigorous analysis based on martingales, our methodology for constructing good irregular codes, and the demonstration that irregular structure improves performance constitute key points of our contribution. We also consider irregular codes under belief propagation. We report the results of experiments testing the efficacy of irregular codes on both binary-symmetric and Gaussian channels. For example, using belief propagation, for rate 1/4 codes on 16000 bits over a binary-symmetric channel, previous low-density parity-check codes can correct up to approximately 16% errors, while our codes correct over 17%. In some cases our results come very close to reported results for turbo codes, suggesting that variations of irregular low density parity-check codes may be able to match or beat turbo code performance
Year
DOI
Venue
2001
10.1109/18.910576
IEEE Transactions on Information Theory
Keywords
Field
DocType
Gaussian channels,decoding,error correction codes,graph theory,Gaussian channels,belief propagation,binary-symmetric channels,code rate,decoding algorithms,error correction codes,hard-decision decoding,irregular codes,irregular graphs,irregular parity-check matrices,irregular structures,low-density parity-check codes,martingales,performance,turbo code performance
Discrete mathematics,BCJR algorithm,Combinatorics,Concatenated error correction code,Low-density parity-check code,Computer science,Turbo code,Block code,Serial concatenated convolutional codes,Linear code,Tornado code
Journal
Volume
Issue
ISSN
47
2
0018-9448
Citations 
PageRank 
References 
292
47.37
15
Authors
4
Search Limit
100292
Name
Order
Citations
PageRank
Michael Luby190101319.35
Michael Mitzenmacher27386730.89
M. A. Shokrollahi31003128.53
Daniel A. Spielman44257638.57