基于多元LDPC码的迭代符号定时恢复  

Iterative Symbol Timing Recovery Based on Non-binary LDPC Codes

作　　者：张强[1] 余忠洋[1] 王力男[2] 白宝明[1] ZHANG Qiang YU Zhong-yang WANG Li-nan BAI Bao-ming(Xidian University State Key Laboratory, Xi＇ an, Shaanxi 710071, China China Electronics Technology Group Corporation 54th Research Institute, Shijiazhuang, Hebei 050002, China)

机构地区：[1]西安电子科技大学综合业务网理论及关键技术国家重点实验室,陕西西安710071 [2]中国电子科技集团公司第五十四研究所,河北石家庄050002

出　　处：《信号处理》2017年第6期819-827,共9页Journal of Signal Processing

基　　金：国家863计划项目"5G新型调制编码与高效链路技术研究开发"(2015AA01A709);通信网信息传输与分发技术重点实验室开放课题(KX162600032)

摘　　要：针对极低/低信噪比深空通信中传统符号定时恢复难的问题,本文提出了一种联合符号定时恢复与多元LDPC迭代译码的方案。该方案将Mueller&Muller符号定时恢复算法与迭代译码方法相结合,对符号周期内的动态时延进行校正。根据译码反馈信息的不同,迭代译码方法可分为基于译码硬信息和译码软信息两种迭代方法。仿真结果表明,在高阶调制、低信噪比和动态时延下,基于两种迭代方法的符号定时恢复算法均取得了接近于理想情况的性能,且收敛速度快,适合于工程实现。其中,由于基于译码软信息迭代的符号定时恢复算法保留了更完整的概率信息,因而性能更优。Considering the difficulty of traditional symbol timing recovery at the extremely low/ low signal-noise-ratio （SNR） in the deep-space communications, an iterative symbol timing recovery method based on non-binary LDPC coded modulation system is proposed. This method can estimate and correct random time delay over the symbol period by combi- ning Mueller and Muller timing error detector with iterative decoding method. According to the type of message feedback from the LDPC decoder, two different kinds of iterative timing recovery strategies are presented, and they are separately based on hard decoding feedback information and soft decoding feedback information. Simulation results show that the symbol timing synchronization algorithm based on these two kinds of decoding feedback information both achieves pretty good performance under the conditions of low SNR, random time delay and high-order modulation, and they perform fast conver- gence, which is of powerful practice. Furthermore, symbol timing synchronization algorithm based on soft feedback deco- ding information performs better, because it keeps more complete probabilistie information.

关 键 词：深空通信 多元LDPC码 符号定时估计 迭代译码 

分 类 号：TN911.23[电子电信—通信与信息系统]