An efficient post processing scheme to lower the error floor of LDPC decoders

Low-Density Parity-Check (LDPC) codes have extensive applications in numerous communication systems. However, iterative LDPC decoders may suffer from error floor. In this paper, a low complexity post processing scheme (PPS) is proposed to significantly improve the error correction performance of a Min-Sum based LDPC decoder in the error floor region. Instead of using trapping set elimination algorithms, the proposed PPS introduces perturbations so that a decoder can escape from undesired local maximums. After decoding failure, for these unreliable code bits, the proposed PPS generates carefully modified soft messages, which are employed in the following decoding iterations. Numerical results demonstrate that the presented PPS significantly lowers the error floor for simulated LDPC codes.

[1]  Gottfried Lechner,et al.  Improved Sum-Min Decoding for Irregular LDPC Codes , 2006 .

[2]  Marc P. C. Fossorier,et al.  Two-dimensional correction for min-sum decoding of irregular LDPC codes , 2006, IEEE Communications Letters.

[3]  Babak Daneshrad,et al.  A performance improvement and error floor avoidance technique for belief propagation decoding of LDPC codes , 2005, 2005 IEEE 16th International Symposium on Personal, Indoor and Mobile Radio Communications.

[4]  Hideki Imai,et al.  Reduced complexity iterative decoding of low-density parity check codes based on belief propagation , 1999, IEEE Trans. Commun..

[5]  Robert Michael Tanner,et al.  A recursive approach to low complexity codes , 1981, IEEE Trans. Inf. Theory.

[6]  David J. C. MacKay,et al.  Weaknesses of Margulis and Ramanujan-Margulis low-density parity-check cCodes , 2003, MFCSIT.

[7]  Gottfried LECHNER.  Improved Sum-Min Decoding of LDPC Codes , .

[8]  Robert G. Gallager,et al.  Low-density parity-check codes , 1962, IRE Trans. Inf. Theory.

[9]  Michael Chertkov,et al.  Reducing the Error Floor , 2007, 2007 IEEE Information Theory Workshop.

[10]  William E. Ryan,et al.  Low-floor decoders for LDPC codes , 2009, IEEE Transactions on Communications.

[11]  J. Sayir,et al.  On the Convergence of Log-Likelihood Values in Iterative Decoding , 2002 .

[12]  Shu Lin,et al.  Low-density parity-check codes based on finite geometries: A rediscovery and new results , 2001, IEEE Trans. Inf. Theory.

[13]  Jinghu Chen,et al.  Density evolution for two improved BP-Based decoding algorithms of LDPC codes , 2002, IEEE Communications Letters.

[14]  T. Wadayama,et al.  Gradient descent bit flipping algorithms for decoding LDPC codes , 2008, ISITA 2008.

[15]  Shu Lin,et al.  Construction of Regular and Irregular LDPC Codes: Geometry Decomposition and Masking , 2007, IEEE Transactions on Information Theory.

[16]  Richard D. Wesel,et al.  Construction of irregular LDPC codes with low error floors , 2003, IEEE International Conference on Communications, 2003. ICC '03..

[17]  Thomas J. Richardson,et al.  Error Floors of LDPC Codes , 2003 .

[18]  Valentin Savin,et al.  Self-corrected Min-Sum decoding of LDPC codes , 2008, 2008 IEEE International Symposium on Information Theory.