一种改进的OFDM时间同步方案

An Improved Algorithm for OFDM Timing Synchronization

时间同步是OFDM系统中最为重要的工作之一,文章对突发OFDM传输系统的定时同步进行研究,对OFDM系统定时同步算法进行改进,克服了以往算法中定时测度存在引起估计模糊的平台现象和多尖峰现象,因此定时同步精度高。改进算法使用了自相关处理,故对载波频率偏差具有强的鲁棒性,而且还具有较强的抗多径干扰能力,相对改进前的算法,改进的定时算法不仅能准确实现OFDM传输系统的帧同步,还能精确地实现符号同步,定时估计在时域内一次性完成,有利于系统载波频率同步实现,降低了频率同步的实现难度。此外,改进算法结构简单,额外开销量小,仅需一个训练符号,这种快速低开销量的同步方法适合突发的OFDM传输系统。

Estimation of time is one of the core issues in an OFDM system. The underlying ideas of OFDM caused by the error timing synchronization has been studied in this paper. OFDM timing algorithm is improved in this paper, and the modified algorithm overcome the shortcomings of the phantom which result in ambiguity of timing estimation and multi-peak would occur in the shortcomings of the conven- tional method. As autocorrelation is used, timing recovery of the proposed is robust to carrier frequency offset and multipath. The timing offset of frame and symbol can be estimated simultaneously in time domain, thus reducing the complexity of timing synchronization. The modified algorithm is simple and the overhead is small, only one training symbol is used. The low overhead and fast algorithm is very suit to synchronizing of a burst OFDM system.