针对特定LDPC码的多子译码器并行组合译码方法

对于分组纠错码的译码，由多个子译码器构建的并行译码系统比单译码器系统有较大的性能提升，但是可实现并行译码处理的子译码器的构造却是一个挑战性难题。为此，该文提出一种针对特定LDPC码的适于BP译码算法运用的多子译码器并行组合译码方法。该方法针对基于本原多项式构造的一类LDPC码的译码尤其有效，其特点是:各个子译码器所依赖的校验矩阵由基础校验矩阵的恰当循环移位获得，而循环移位量的恰当选择则依赖了m序列(唯一对应于本原多项式)的采样特性；各个子BP处理过程的迭代次数设置为其校验矩阵最短环长的一半，由此可消除短环对BP译码性能的影响；各子BP处理模块输出的信息比特外信息再经过基础译码模块处理后与并行配置的基础译码输出，一并进行最大似然判决处理并获得译码输出。该方法的仿真结果显示，在误码率为10?5且多子译码器并行组合译码方法在设置5个子译码模块时，其译码性能比原单译码器译码方法高约0.4 dB。

Parallel Decoding Method with Multiple Sub-Decoders for Specific LDPC Code

The parallel decoding system with multiple sub-decoders has much performance improvement than that of single-decoder system for decoding the block codes. However, the construction of sub-decoders for the parallel decoding implementation is still the challenging problem. To solve this problem, this paper proposes a parallel decoding method with multiple sub-decoders based on BP (belief propagation) algorithm for some specific low-density parity-check (LDPC) codes. This method is particularly effective for decoding the LDPC code generated via primitive polynomial. The method has characteristics as the parity-check matrix used for each sub-decoder depends on a proper cyclic shift of the original parity-check matrix, and the number of cyclic shift depends on the sampling property of the m sequence (which uniquely corresponds to a primitive polynomial). The iteration times of each BP processes in the sub-decoder are set as half of the girth of Tanner graph of the parity-check matrix, thus the affection of short cycles on BP performance would be eliminated. The output extrinsic information for each bit generated by the sub-decoder is processed further by a decoding module to output the candidate codeword, and then the LMS module picks out the maximum likelihood candidate codeword as the output of the decoding system. The simulation results show that the performance of the proposed parallel decoding method with 5 sub-decoders is about 0.4 dB superior to that of the original single-decoder decoding method at the bit error rate of 10?5.