低复杂度的LDPC码联合编译码构造方法研究  

Joint encoding-decoding construction of LDPC codes with reduced complexity

作　　者：姜明[1] 赵春明[1] 何善宝[1] 单鸣[1] 

机构地区：[1]东南大学移动通信国家重点实验室,江苏南京210096

出　　处：《通信学报》2005年第2期80-86,共7页Journal on Communications

基　　金：国家重大自然基金资助项目(60496311)

摘　　要：LDPC码因为其具有接近香农限的译码性能和适合高速译码的并行结构,已经成为纠错编码领域的研究热点。LDPC码校验矩阵的构造是基于稀疏的随机图,所以该类码字编码和译码的硬件实现比较复杂。以单位阵的循环移位阵为基本单元,构造LDPC码的校验矩阵,降低了LDPC码在和积算法下的译码复杂度。同时考虑到LDPC码的编码复杂度,给出了一种可以简化编码的结构。针对该方案构造的LDPC码,提出了消除其二分图上的短圈的方法。通过大量的仿真和计算分析,本文比较了这种LDPC码和随机构造的LDPC码在误码率性能,圈长分布以及最小码间距估计上的差异。LDPC codes are now one of intensely studied areas in coding due to their near Shannon limit performance and parallel decoding architecture. Because the LDPC codes parity-check matrices are defined in terms of sparse random graphs, the implementation of the decoding and encoding is of high complexity. A new design methodology of LDPC codes, which are constructed by the cyclic shift matrices, is proposed in order to reduce the decoding complexity under the Sum-Product algorithm. Meanwhile,the encoding problem of LDPC codes is also considered, then a simplified encoding structure is given. A new procedure of removing the short loops from the bipartite graph is demonstrated according to the construction scheme of our LDPC codes. Performance comparisons between our codes and random constructed LDPC codes on BER, loop distributions and minimum distance estimation are given by extensive simulations and numerical analysis.

关 键 词：纠错编码 低密度奇偶校验码 循环移位阵 和积算法 

分 类 号：TN929.533[电子电信—通信与信息系统]