基于SCPPM码辅助的迭代定时同步技术  

Timing Synchronization Technique based on SCPPM Code Auxiliary under Large Timing Error

作　　者：向劲松[1] 张培 王举[1] 邓晨辉[1] 蒋豪[1] 

机构地区：[1]重庆邮电大学通信与信息工程学院,重庆400065

出　　处：《光通信研究》2017年第6期57-61,共5页Study on Optical Communications

基　　金：国家自然科学基金资助项目(61571072)

摘　　要：针对大定时误差下串行级联脉冲位置调制(SCPPM)同步难的问题,提出一种基于期望最大化(EM)算法估计的SCPPM码辅助迭代定时同步方法。该方法首先由SCPPM译码输出软信息构造出评价函数,先进行大范围定时偏移的粗同步,之后再利用EM算法进行细同步,并且通过简化评价函数以及搜索方式降低同步算法的复杂度。仿真结果表明,该方法能够在大定时误差下有效地实现系统同步,与使用EM算法相比,其有效同步范围得到了大幅提高。In order to address the problem of the Serially Concatenated Pulse-Position Modulation（SCPPM）synchronization in large timing error,an SCPPM code auxiliary iterative timing synchronization method based on Expectation Maximization（EM）estimation is proposed.Firstly,the method constructs the evaluation function from SCPPM decoding output soft information,achieving the coarse synchronization of wide range timing offsets,following the EM algorithm for fine synchronization.Then,the complexity of synchronization algorithm is reduced by simplifying the evaluation function and searching method.The simulation results show that the proposed method can realize the system synchronization effectively under large timing error,and the effective synchronization range is greatly improved compared with the EM algorithm.

关 键 词：空间光通信 SCPPM码 期望最大化算法 码辅助 迭代定时同步 

分 类 号：TN911.22[电子电信—通信与信息系统]