基于有限域的结构化LDPC码构造精选.pdf

第七届卫星通信新技术新业务年会 2011.3 基于有限域的结构化 LDPC 码构造 张仲明， 马立波 （北京跟踪与通信技术研究所，北京 100094） 摘要：随机 LDPC 码的实现相当复杂，相对随机 LDPC码而言结构化 LDPC 码具有实现复杂度低的 特点。LDPC码通常采用 Tanner 图上的置信度传播算法进行迭代译码。对于无圈的 Tanner 图，即围 长为无穷大的 Tanner 图，置信度传播算法是一种最优译码算法。本文提出了一种基于行列约束的 LDPC 码代数构造方法，这种方法可以构造出两类二元的结构化 LDPC 码,它的围长不小于 6。仿真结 果表明，构造出来的 LDPC 码在 AWGN 信道下采用置信度传播算法译码就误块率与误码率等方面的性 能均可与标准码相当。 关键词：低密度奇偶校验码；有限域；围长；置信度传播算法 Construction of Stuctured LDPC Codes based on Finite Fields ZHANG Zhong-ming，MA Li-bo （Beijing Institute of Tracking and Telecommunications Technology, Beijing 100094, China） Abstract：Implementation of computer-generated random low-density parity-check(LDPC) codes can be rather complex. Structured LDPC codes have implementation advantage over random LDPC codes. The usual algorithm for the decoding of LDPC codes is the iterative belief-propagation algorithm (BPA), op on a Tanner graph of the code. It is well known that cycle-free Tanner graph with BPA algorithm yields optimal decoding. The girth of the cycle-free Tanner graph is infinite. In this paper, we present an algebraic method for constructing two types of binary structured LDPC codes based on the row-column constraint. The codes constructed by this method have girths at least 6. Experimental results show that the constructed LDPC codes decoded with BPA over the AWGN channel can perform as well as standard LDPC codes in terms of bit-error rate and block error rate. 529 第七届卫星通信新技术新业务年会 2011.3 Key words：Low-Density Parity-Check Codes；Finite Fields；Girth；Belief-Propagation algorithm 1. 前言 随着信息传输速率的急剧提高，卫星通信使用传统信道编码和 QPSK