陆地移动卫星信道中的LDPC码分析与优化  

Analysis and optimization of the LDPC code on the land mobile satellite channel

作　　者：戴精科 林开亮[2] DAI Jingke;LIN Kailiang(Information Engineering Department,Rocket Force Univ.of Engineering;School of Science,Northwest A＆F Univ.,Xi＇an 712100,China)

机构地区：[1]火箭军工程大学信息工程系,陕西西安710025 [2]西北农林科技大学理学院,陕西西安712100

出　　处：《西安电子科技大学学报》2018年第3期52-57,共6页Journal of Xidian University

基　　金：国家自然科学基金资助项目(61501469);中国博士后科学基金资助项目(2015M572782)

摘　　要：针对移动环境中信号易受到信道衰落影响的问题,将低密度奇偶检验码应用于经历阴影-赖斯衰落的陆地移动卫星信道,证明了信道对称条件,给出了译码稳定性条件,推导了香农容量限;基于密度进化理论获得译码门限,并结合差分进化算法对不规则码的度分布进行了优化.仿真结果表明,译码门限能够很好地预测码字性能,且优化的不规则码门限距离香农限仅有0.1dB;在相同码长条件下,优化码的误码性能优于规则码和新一代数字卫星广播标准使用的码字,适合陆地移动卫星信道传输.The low-density parity-check （LDPC） code is applied to the land mobile satellite （LMS ） channelwith Shadowcd-Rician fading, where both of symmetry and stability conditions are proven, and the Shannon limit is calculated. The decoding thresholds are obtained based on density evolution, and the degreedistributions of irregular codes are optimized using differential evolution. Simulation results show that thethresholds well predict the code performance, and that the optimized code has a threshould within 0.1dB of the Shannon limit. With the same code-length, the optimized code outperforms both the regular code and irregular code employed by the Digital Video Broad casting-Sat ellit c-Sccond Generation （ DVB-S2 ）, indicating its advantage of information transmission over the LMS channel.

关 键 词：低密度奇偶检验码 阴影莱斯信遒 密度进化 译码门限 优化 

分 类 号：TN927[电子电信—通信与信息系统]