A novel soft reliability-based iterative majority-logic decoding algorithm with uniform quantization

In this paper, a novel soft reliability-based iterative majority-logic decoding algorithm with uniform quantization is proposed for regularly structured low density parity-check (LDPC) codes. A weighted measure is introduced for each check-sum of the parity-check matrix and a scaling factor is used to weaken the overestimation of extrinsic information. Furthermore, the updating process of the reliability measure takes advantage of turbo-like iterative decoding strategy. The main computational complexity of the proposed algorithm only includes logical and integer operations with the bit uniform quantization criterion. Simulation results show that the novel decoding algorithm can achieve excellent error-correction performance and a fast decoding convergence speed. This work has been supported by the National Natural Science Foundation of China (Nos.61472464, 61671091 and 61471075), the Natural Science Foundation of Chongqing Science and Technology Commission (No.cstc2015jcyjA0554), the Program for Innovation Team Building at Institutions of Higher Education in Chongqing (No.J2013-46), and the Undergraduate Science Research Training Project for Chongqing University of Posts and Telecommunications (No.A2016-61). E-mail:yuanjg@cqupt.edu.cn      

光通信系统中一种改进的LLR-BP译码算法

光通信系统中低密度奇偶校验(Low-density Parity-check,LDPC)码采用对数似然比置信传播(Log-likelihood Ratio Belief Propagation,LLR-BP)算法进行译码时,在高信噪比区域迭代译码过程中会出现变量节点外部信息振荡不收敛而导致译码纠错性能的降低.为满足光通信系统的要求,提出了一种削弱外部消息振荡的改进LLR-BP译码算法.该算法通过引入加权系数平衡前后两次迭代之间变量节点传递的外部信息,明显减缓了外部信息的振荡现象.仿真结果表明:与传统LLR-BP译码算法相比,该改进LLR-BP算法具有更佳的误码性能,同时降低变量节点外部信息振荡现象并加快了译码的收敛速度.