基于PCPEG算法的准循环LDPC码构造

摘要

渐进边增长(PEG)算法构造的低密度奇偶校验码(LDPC)在保证局部围长最大时仍有较多数目的短环。针对该问题，提出一种新的准循环LDPC码构造方法。该方法在PEG算法中采用环多项式(PC)标记，利用PC-PEG方法构造的矩阵作为基矩阵，并对其进行准循环扩展，以消除基矩阵中的短环。实验结果表明，该方法构造的 LDPC 码可大幅减少短环的数目。同时由于引入了准循环结构，能降低编码复杂度。%For the problems that the Progressive Edge Growth(PEG) algorithm can achieve large local girth, but ignores the number of shortest cycles, this paper proposes an improved PEG algorithm, which is called PC-PEG algorithm, using Polynomial of Cycle(PC). After a basic matrix is constructed by PCPEG algorithm, circulant permutation matrices will replace the short cycle in the basic matrix. The new method can eliminate effectively the short cycles in the basic matrix without changing the degree distribution fraction of the basic matrix. Experimental results show that the proposed method not only reduces the number of small cycle significantly, but also reduces the coding complexity for its quasi-cyclic structure.