多用户OFDM系统的测距定时同步算法

Ranging Timing Synchronization Algorithms of Multi-User OFDM System

在OFDMA系统中,上行链路的定时误差主要来自远近效应,导致用户间符号到达时刻不一致,因此,同步过程主要依靠测距来完成同步参数估计,再通过反馈机制予以调整。通过对OFDMA几种测距定时同步算法的研究,仿真分析了各自性能及运算复杂度,并在此基础上提出了一种联合同步方案,将3种算法结合应用于不同用户量的接入环境,以满足性能及复杂度的平衡需求。

In the Orthogonal Frequency Division Multiple Access（OFDMA）systems,as the near/far problems bring on the differences of user signals arrival time,the uplink timing mainly achieves the synchronous parameter estimation by the ranging process,while make adjustment through the feedback mechanism.Through the research of several ranging timing synchronization algorithms,we perform simulations and analysis for the performance and operation complexity respectively.Also,an united-synchronization scheme is proposed as combining the three methods,which will be applied to different access environments of multiuser capacity,to satisfy the balance requirement of performance and complexity.