EXIT Chart Analysis of Binary Message-Passing Decoders

Binary message-passing decoders for LDPC codes are analyzed using EXIT charts. For the analysis, the variable node decoder performs all computations in the L-value domain. For the special case of a hard decision channel, this leads to the well-know Gallager B algorithm, while the analysis can be extended to channels with larger output alphabets. By increasing the output alphabet from hard decisions to four symbols, a gain of more than 1.0 dB is achieved using optimized codes. For this code optimization, the mixing property of EXIT functions has to be modified to the case of binary message-passing decoders.

[1]  Masoud Ardakani,et al.  Designing irregular LPDC codes using EXIT charts based on message error rate , 2002, Proceedings IEEE International Symposium on Information Theory,.

[2]  Michael Tuchler,et al.  EXIT charts of irregular codes , 2002 .

[3]  Evangelos Eleftheriou,et al.  Regular and irregular progressive edge-growth tanner graphs , 2005, IEEE Transactions on Information Theory.

[4]  Rüdiger L. Urbanke,et al.  Design of capacity-approaching irregular low-density parity-check codes , 2001, IEEE Trans. Inf. Theory.

[5]  Joachim Hagenauer,et al.  Iterative decoding of binary block and convolutional codes , 1996, IEEE Trans. Inf. Theory.

[6]  Ingmar Land,et al.  Reliability information in channel decoding: practical aspects and information theoretical bounds , 2005 .

[7]  Rüdiger L. Urbanke,et al.  The capacity of low-density parity-check codes under message-passing decoding , 2001, IEEE Trans. Inf. Theory.

[8]  Masoud Ardakani,et al.  Properties of optimum binary message-passing decoders , 2005, IEEE Transactions on Information Theory.

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

[10]  M. Tuchler,et al.  Design of serially concatenated systems depending on the block length , 2004, IEEE Transactions on Communications.

[11]  Michael Tüchler,et al.  Design of Serially Concatenated Systems Depending on the Block Length , 2004, IEEE Trans. Commun..

[12]  Stephan ten Brink,et al.  Extrinsic information transfer functions: model and erasure channel properties , 2004, IEEE Transactions on Information Theory.

[13]  Masoud Ardakani,et al.  A more accurate one-dimensional analysis and design of irregular LDPC codes , 2004, IEEE Transactions on Communications.