一种改善LDPC译码性能的新方法  

New approach to improving performance of LDPC decoding

作　　者：张大伟[1] 解小建[1] 徐凤军[2] 

机构地区：[1]91872部队 [2]海军702厂

出　　处：《电子测量技术》2011年第3期5-7,24,共4页Electronic Measurement Technology

摘　　要：由于LDPC码可以逼近香农限,近年来在国内外编码研究与应用中受到广泛关注,然而,LDPC码迭代译码存在误码平底,限制了LDPC码的进一步应用。陷阱集是导致LDPC码误码平底的主要因素,为了消除陷阱集的影响,提出一种基于陷阱集变量节点消息重置译码方法。当译码器进入陷阱状态后,重新计算陷阱集变量点消息,使译码器在后续迭代过程中脱离陷阱状态。新方法结合LDPC码二部图的特点,利用陷阱集以外变量节点的正确消息对陷阱集变量节点消息进行重置处理,提高了LDPC迭代译码器收敛速度和降低误码平底。实验结果表明新方法能够进一步改善LDPC译码器性能。Low-density parity-check codes have been widely concerned in recent years in researching and application of coding due to their near-capacity performance.One of the most significant impediments to use of LDPC codes in many communication and storage systems is the err-rate floor phenomenon associated with their iterative decoding decoders.Trapping sets have been identified as one of the main factors causing error-rate floor.In order to mitigate the effect of trapping sets during the iterations of iterative decoding,a new LDPC decode mechanism with trapping sets message reset is proposed.Once the decoder detects a trapping event,it switches to trapping sets message reset process which helps the decoder escape from the trapping state in the following iterative decoding process.New method makes use of the structure of the LDPC code bipartite graph and updates messages of the variable nodes in the trapping sets correctly from messages outside,which improves both the decoder＇s convergence speed and decoding performance.Experiment results proved that the proposed technique is able to provide performance improvement for the LDPC decoder.

关 键 词：低密度奇偶校验码 置信度传播算法 陷阱集 

分 类 号：TN911.22[电子电信—通信与信息系统]