基于消息传播的LDPC码环统计算法

A message passing algorithm for counting cycles in LDPC codes

基于节点间的外部消息传播机制,提出一种新的LDPC码环统计算法,使用和积算法处理消息传播的过程,可有效地统计Tanner图中长度为g,g+2,…,2g-2的环的数量,其中g为围长。与现有方法相比,本算法复杂度较低,特别适合于围长较长的LDPC码。

An algorithm based on extrinsic message passing is presented for counting, short cycles in Tanner graph. It uses sum-product algorithm to handle the process of message passing. The algorithm is capable of counting cycles of length g,g ＋2, ... ,2g-2, where g is the girth of the graph. Compared with the existing algorithms, the proposed algorithm is outperformed, particularly in terms of LDPC codes with large girth.