引入行重参数的改进不规则LDPC码译码算法  

Improved irregular LDPC code decoding algorithm by introducing row weight parameters

作　　者：刘毓 王婵 拜林 李伟东 郝耀辉 LIU Yu;WANG Chan;BAI Lin;LI Wei-dong;HAO Yao-hui(School of Communication and Information Engineering,Xi'an University of Posts and Telecommunications,Shaanxi Xi'an,710121,China)

机构地区：[1]西安邮电大学通信与信息工程学院,陕西西安710121

出　　处：《光电子．激光》2021年第5期457-461,共5页Journal of Optoelectronics·Laser

基　　金：科技部与烽火通信合作项目《面向25/100GPON系统设备研制与示范》(2018YFB2201305)资助项目。

摘　　要：低密度奇偶校验(LDPC)码是一种逼近香农极限的线性分组码,而好的非规则LDPC码其性能优于同码率的规则码。在非规则LDPC码的对数似然比置信传播(LLR-BP)译码算法中,由于行重大小的不同,校验节点对伪后验判决贡献的外部信息不同,为此提出一种基于行重的改进LLR-BP译码算法,该算法引入行权重系数,用以调整不同行重外部信息的作用,提高了系统的译码性能。仿真结果表明:在低信噪比时,改进的LLR-BP译码算法对译码性能与标准的LLR-BP译码算法的性能几乎相同;在中高信噪比时,改进的LLR-BP译码算法的误码性能优于LLR-BP译码算法,在码长为64,误码率是10-5时,改进LLR-BP译码算法较之传统LLR-BP译码算法的编码增益提高了0.15 dB。Low-density parity check(LDPC)code is a linear block code approaching the Shannon limit,and good irregular LDPC codes have better performance than regular codes with the same code rate.In the log-likelihood ratio belief propagation(LLR-BP)decoding algorithm of irregular LDPC codes,due to the difference of the line size,the external information contributed by the check node to the pseudo posterior decision is different.Therefore,an improved LLR-BP decoding algorithm based on row weight is proposed.The algorithm introduces row weight coefficients to adjust the effect of different row weight external information and improve the decoding performance of the system.The simulation results show that at low signal-to-noise ratio,the improved log-likelihood ratio belief propagation decoding algorithm has almost the same decoding performance as the standard log-likelihood ratio belief propagation decoding algorithm.At medium and high signal-to-noise ratios,the improved LLR-BP decoding algorithm has better error performance than LLR-BP decoding algorithm.When the code length is 64 and the error rate is 10-5,the improved LLR-BP decoding algorithm is compared with the traditional LLR-BP decoding algorithm.The codinggain is increased by 0.15 dB.

关 键 词：光通信 低密度奇偶校验码 对数似然比置信传播译码算法 行重 外部信息 

分 类 号：TN911.22[电子电信—通信与信息系统]