Gamma-Gamma信道下LDPC码译码算法性能分析.pdfVIP

第35卷摇 第3期 吉林 大学学报 ( 息科 学版) Vol.35摇 No.3 2017年5月 Journal ofJilinUniversity (Information ScienceEdition) May2017 文章编号:1671鄄5896(2017)03鄄0261鄄07 Gamma鄄Gamma信道下 LDPC码译码算法性能分析 徐摇 峰,赵晓晖 (吉林大学 通信工程学院,长春 130012) 摘要:为降低低密度奇偶校验(LDPC:Low鄄Density Parity鄄Cheek)码译码算法的复杂度,同时提高通信系统性能, 在研究对数似然比置信传播(LLR鄄BP:Log鄄Likelihood Ratio Belief Propagation)算法及其简化的译码算法基础上, 提出了一种基于归一化最小和(NMS:Normalized Min Sum)算法的改进算法。 深入研究了Gamma鄄Gamma分布 模型,并将Gamma鄄Gamma分布作为仿真的信道模型,应用Matlab仿真比较了LLR鄄BP及其简化算法在不同湍 流强度信道下的性能。 仿真结果表明,无论在AWGN(Additive White Gaussian Noise)信道还是不同湍流强度的 Gamma鄄Gamma信道下,改进算法在几种算法中都有较好的译码性能,尤其是在中湍流和强湍流信道下改进算 法的性能优势更为明显。 通过码长对BER(Bit Error Rate)影响的仿真结果表明,适当增加码长可有效改善算法 的性能。 关键词:低密度奇偶校验码;Gamma鄄Gamma分布;LLR鄄BP算法;最小和算法;归一化BP算法 中图分类号:TN929.1 文献标识码:A Performance Analysis of LDPC Decoding Algorithm under Gamma鄄Gamma Channel XU Feng,ZHAO Xiaohui (College of Communication Engineering,Jilin University,Changchun 130012,China) Abstract:In order to reduce the LDPC (Low鄄Density Parity鄄Cheek) complexity of decoding algorithm,studied the LLR BP (Log鄄Likelihood Ratio Belief Propagation algorithm) and its simplified decoding algorithm,and an improved algorithm based on NMS (Normalized Min Sum) algorithm is proposed;studied the Gamma鄄Gamma distribution model and Gamma鄄Gamma distribution as the channel model are studied. The performance of LLR鄄 BP and its simplified algorithm under different turbulence intensities are compared with Matlab,the simulation results show that both in the AWGN (Additive White Gaussian Noise) or different turbulence intensity Gamma鄄 Gamma channel, the improved algorithm has better performance in decoding algorithms in particular, the performance advantages of the improved algorithm in stron