Decoding of low-density parity-check codes in non-Gaussian channels

This paper studies the performance of low-density parity-check codes decoded by the iterative message-passing algorithm (MPA) in heavy-tailed, non-Gaussian noise channels. Through detailed examination on the decoding procedure and observation on the decoding trajectory, impulsive noise is found to c...

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Main Author: Chuah, T.C.
Format: Article
Language:English
Published: 2005
Subjects:
Online Access:http://shdl.mmu.edu.my/2165/
http://shdl.mmu.edu.my/2165/1/1488.pdf
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author Chuah, T.C.
author_facet Chuah, T.C.
author_sort Chuah, T.C.
building MMU Institutional Repository
collection Online Access
description This paper studies the performance of low-density parity-check codes decoded by the iterative message-passing algorithm (MPA) in heavy-tailed, non-Gaussian noise channels. Through detailed examination on the decoding procedure and observation on the decoding trajectory, impulsive noise is found to constitute a major channel impairment for the Gaussian-optimised MPA. Two main factors contributing to this non-robustness, which lead to error propagation and produce uncorrectable and undetected errors, are identified. To compensate for this shortfall, an effective countermeasure is outlined and a low-complexity robust MPA (RMPA) in both probability and log-domains is proposed. The RMPA can be implemented by appending the standard MPA with a nonlinear filter bank, thus requiring no major modifications. The nonlinear filter bank performs impulsive noise suppression and prevents the formation of overly strong priors. This gives room for performance improvements via iterative decoding. The nonlinear functions embedded in the filter bank can be stored as a lookup table or implemented efficiently using the CORDIC algorithm, which is very suitable for VLSI implementation. For severe impulsive noise, the RMPA significantly outperforms the MPA with performance gains typically exceeding 10 dB for bit error probabilities below 10(-2) with moderate codeword lengths. The performance of the sign-MPA (SMPA), which imposes a hard-limiting procedure on the received codewords, is also investigated.
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spelling mmu-21652011-09-19T08:23:39Z http://shdl.mmu.edu.my/2165/ Decoding of low-density parity-check codes in non-Gaussian channels Chuah, T.C. TA Engineering (General). Civil engineering (General) This paper studies the performance of low-density parity-check codes decoded by the iterative message-passing algorithm (MPA) in heavy-tailed, non-Gaussian noise channels. Through detailed examination on the decoding procedure and observation on the decoding trajectory, impulsive noise is found to constitute a major channel impairment for the Gaussian-optimised MPA. Two main factors contributing to this non-robustness, which lead to error propagation and produce uncorrectable and undetected errors, are identified. To compensate for this shortfall, an effective countermeasure is outlined and a low-complexity robust MPA (RMPA) in both probability and log-domains is proposed. The RMPA can be implemented by appending the standard MPA with a nonlinear filter bank, thus requiring no major modifications. The nonlinear filter bank performs impulsive noise suppression and prevents the formation of overly strong priors. This gives room for performance improvements via iterative decoding. The nonlinear functions embedded in the filter bank can be stored as a lookup table or implemented efficiently using the CORDIC algorithm, which is very suitable for VLSI implementation. For severe impulsive noise, the RMPA significantly outperforms the MPA with performance gains typically exceeding 10 dB for bit error probabilities below 10(-2) with moderate codeword lengths. The performance of the sign-MPA (SMPA), which imposes a hard-limiting procedure on the received codewords, is also investigated. 2005-12 Article NonPeerReviewed application/pdf en http://shdl.mmu.edu.my/2165/1/1488.pdf Chuah, T.C. (2005) Decoding of low-density parity-check codes in non-Gaussian channels. IEE Proceedings - Communications, 152 (6). pp. 1086-1097. ISSN 13502425 http://dx.doi.org/10.1049/ip-com:20050154 doi:10.1049/ip-com:20050154 doi:10.1049/ip-com:20050154
spellingShingle TA Engineering (General). Civil engineering (General)
Chuah, T.C.
Decoding of low-density parity-check codes in non-Gaussian channels
title Decoding of low-density parity-check codes in non-Gaussian channels
title_full Decoding of low-density parity-check codes in non-Gaussian channels
title_fullStr Decoding of low-density parity-check codes in non-Gaussian channels
title_full_unstemmed Decoding of low-density parity-check codes in non-Gaussian channels
title_short Decoding of low-density parity-check codes in non-Gaussian channels
title_sort decoding of low-density parity-check codes in non-gaussian channels
topic TA Engineering (General). Civil engineering (General)
url http://shdl.mmu.edu.my/2165/
http://shdl.mmu.edu.my/2165/
http://shdl.mmu.edu.my/2165/
http://shdl.mmu.edu.my/2165/1/1488.pdf