基于围长约束的非规则短码长LDPC码构造改进算法  

An Improved irregular short LDPC code construction algorithm based on girth constraints

作　　者：章坚武[1] 颜欢[1] 包建荣[1,2] 

机构地区：[1]杭州电子科技大学通信工程学院,浙江杭州310018 [2]浙江省综合信息网技术重点实验室,浙江杭州310027

出　　处：《电路与系统学报》2012年第2期118-123,117,共7页Journal of Circuits and Systems

基　　金：国家自然科学基金(61001133;61102066);中国博士后科学基金(2011M500999);浙江省综合信息网技术重点实验室开放资助课题(201101)

摘　　要：本文提出了一种基于围长约束的非规则短码长LDPC编码的改进算法。在每次生成的列向量有多个最大平均围长的情况下,通过选择其中局部短环个数最少,及最小渐进环外消息度(ACE)最大的列向量,依次放入当前校验矩阵完成编码构造,能有效改善影响编码性能的环特性。其中,计算短环数和最小ACE值的方法,采用基于图论的深度优先算法。仿真结果表明:该算法构造的非规则短码长LDPC码的性能优于原基于围长约束的算法及PEG算法所构造的码字。This paper proposes an improved girth-constraint based algorithm to construct the irregular short LDPC codes. Under the condition of more than one largest average girths at every generated column vector, it can improve the loop property of the code efficiently, which affects the code performance, by choosing the column vector with least short local rings and largest minimum Approximate Cycle Extrinsic-message-degrees （ACEs） in turn. And the method of calculating the number of short rings and minimum ACE value is based on the depth-first algorithm in graph theory. Simulation results show that the irregular short LDPC code, constructed by our algorithm, shows better performance than that of both the original algorithm based on girth constraints and the PEG algorithm.

关 键 词：LDPC码 围长约束 短环个数 ACE值 

分 类 号：TN911.22[电子电信—通信与信息系统]