For one class of Low-Density Parity-Check(LDPC)codes with low row weight in theirparity check matrix,a new Syndrome Decoding(SD)based on the heuristic Beam Search(BS),labeledas SD-BS,is put forward to improve the erro...For one class of Low-Density Parity-Check(LDPC)codes with low row weight in theirparity check matrix,a new Syndrome Decoding(SD)based on the heuristic Beam Search(BS),labeledas SD-BS,is put forward to improve the error performance.First,two observations are made andverified by simulation results.One is that in the SNR region of interest,the hard-decision on thecorrupted sequence yields only a handful of erroneous bits.The other is that the true error pattern forthe nonzero syndrome has a high probability to survive the competition in the BS,provided sufficientbeam width.Bearing these two points in mind,the decoding of LDPC codes is transformed into seekingan error pattern with the known decoding syndrome.Secondly,the effectiveness of SD-BS dependsclosely on how to evaluate the bit reliability.Enlightened by a bit-flipping definition in the existingliterature,a new metric is employed in the proposed SD-BS.The strength of SD-BS is demonstrated viaapplying it on the corrupted sequences directly and the decoding failures of the Belief Propagation(BP),respectively.展开更多
Network Coding (NC) brings correlation between the coded signals from different sources, which makes the system more vulnerable to the decode error at relay. Conventional Cyclic Redundancy Code (CRC) has been implemen...Network Coding (NC) brings correlation between the coded signals from different sources, which makes the system more vulnerable to the decode error at relay. Conventional Cyclic Redundancy Code (CRC) has been implemented for error bit detection. However, its error correction is simply ignored. To fully exploit this feature, this paper proposes a novel joint Log-Likelihood Ratio (LLR) CRC error mitigation for NC two way relay channel. Specific thresholds are designed to estimate the error number of data block and identify those which can be recovered if the number is within the error correction scope of CRC. We examine two modes of the thresholds, one based on the average Bit Error Rate (BER) of source-relay link, while the other based on that of instantaneous one. We provide the full analysis for the Pair-wise Error Probability (PEP) performance of the scheme. A variety of numerical results are presented to reveal the superiority of the proposed scheme to conventional CRC NC under independent Rayleigh fading channels. Moreover, the efficiencies of the proposed thresholds are also validated.展开更多
基金the National Science Foundation of China(No.60472104).
文摘For one class of Low-Density Parity-Check(LDPC)codes with low row weight in theirparity check matrix,a new Syndrome Decoding(SD)based on the heuristic Beam Search(BS),labeledas SD-BS,is put forward to improve the error performance.First,two observations are made andverified by simulation results.One is that in the SNR region of interest,the hard-decision on thecorrupted sequence yields only a handful of erroneous bits.The other is that the true error pattern forthe nonzero syndrome has a high probability to survive the competition in the BS,provided sufficientbeam width.Bearing these two points in mind,the decoding of LDPC codes is transformed into seekingan error pattern with the known decoding syndrome.Secondly,the effectiveness of SD-BS dependsclosely on how to evaluate the bit reliability.Enlightened by a bit-flipping definition in the existingliterature,a new metric is employed in the proposed SD-BS.The strength of SD-BS is demonstrated viaapplying it on the corrupted sequences directly and the decoding failures of the Belief Propagation(BP),respectively.
基金Supported by the National 973 Programs (2013CB329104)the National Natural Science Foundations of China (No. 61071090, No. 61171093)+3 种基金the Postgraduate Innovation Programs of Scientific Research of Jiangsu Province (CXZZ11_0388)Jiangsu Province Natural Science Foundation Key Projects (11KJA510001)National Science and Technology Key Projects (2011ZX03005-004-003)Jiangsu 973 Projects (BK2011027)
文摘Network Coding (NC) brings correlation between the coded signals from different sources, which makes the system more vulnerable to the decode error at relay. Conventional Cyclic Redundancy Code (CRC) has been implemented for error bit detection. However, its error correction is simply ignored. To fully exploit this feature, this paper proposes a novel joint Log-Likelihood Ratio (LLR) CRC error mitigation for NC two way relay channel. Specific thresholds are designed to estimate the error number of data block and identify those which can be recovered if the number is within the error correction scope of CRC. We examine two modes of the thresholds, one based on the average Bit Error Rate (BER) of source-relay link, while the other based on that of instantaneous one. We provide the full analysis for the Pair-wise Error Probability (PEP) performance of the scheme. A variety of numerical results are presented to reveal the superiority of the proposed scheme to conventional CRC NC under independent Rayleigh fading channels. Moreover, the efficiencies of the proposed thresholds are also validated.
