光子学报, 2012, 41 (3): 277, 网络出版: 2012-03-30
基于MMSE的大气激光通信中LDPC码BP译码算法研究
Optimization of Two BP-based Decoding Algorithms for LDPC Codes Based on MMSE Criterion under Weak Turbulence Channel
大气激光通信 低密度奇偶校验码 最小均方误差准则 改进的置信度传播算法 Free space laser communication LDPC codes MMSE criterion Improved BP algorithms
摘要
针对大气激光通信中低密度奇偶校验码(LDPC)置信传播(BP)译码算法复杂度高的问题,对几类BP-Based简化译码算法进行了分析,并基于最小均方误差准则(MMSE)对Scaled BP-Based和Offset BP-Based两类改进译码算法的优化设计进行了探讨,得出两类算法的最优校正因子,并给出了数值计算.在不同的湍流强度下,对码长1008的(6,3)比特填充LDPC码进行了仿真实验,结果表明,对于短码长的LDPC码,当译码BER=10-5时, 最小和算法(UMP BP-Based)相对于BP算法有0.1~0.15 dB的译码性能损失;基于MMSE设计的两类算法相比BP算法大大降低复杂度的同时,译码性能与BP算法相当,甚至优于BP算法,优于UMP BP-Based算法0.075~0.15 dB.
Abstract
Due to high complexity of Belief Propagation(BP) algorithm, several kind of BP-based simplified decoding algorithms are analyzed. Based on the Minimum Mean Square Erro(MMSE) criterion, optimal design of the scaled BP-based and offset BP-based algorithms is discussed. The theoretical formulas and numerical calculations on the optimal factors for these two BP-based algorithms are provdied. The simualtion resutls for the (6,3)regualr LDPC codes of lengths 1008 on the weak atmospheric turbulence channel demonstrate that the scaeld BP-based and offset BP-based aglorithms with the proposed factors are better than Min-Sum Algorithm, and even can achieve the performance better than that of the BP algorithm,and have lower complexity compared with BP algortihm.
冷蛟锋, 郝士琦, 吕旭光, 周建国, 赵楠翔. 基于MMSE的大气激光通信中LDPC码BP译码算法研究[J]. 光子学报, 2012, 41(3): 277. LENG Jiao-feng, HAO Shi-qi, L Xu-guang, ZHOU Jian-guo, ZHAO Nan-xiang. Optimization of Two BP-based Decoding Algorithms for LDPC Codes Based on MMSE Criterion under Weak Turbulence Channel[J]. ACTA PHOTONICA SINICA, 2012, 41(3): 277.