一种OFDM系统中的符号定时同步方法  

A New Method of OFDM Time Synchronization

作　　者：严家明[1] 冯波[1] 毛瑞娟[1] 

机构地区：[1]西北工业大学,陕西西安710072

出　　处：《计算机仿真》2008年第12期151-153,266,共4页Computer Simulation

摘　　要：正交频分复用(OrthogonalFrequencyDivisionMultiplexing,OFDM)是一种高效的数据传输技术,具有良好的抗频率选择性衰落能力,并且提高了频谱利用率。但是OFDM对同步误差十分敏感,特别是符号同步误差。这样会导致解调性能迅速恶化,从而使整个OFDM系统性能下降。传统的MLE算法虽对符号定时估计很有效,但在ISI干扰情况下性能不高,Schmidl提出的利用训练序列的同步算法虽对符号定时估计很有效,但在ISI干扰以及低信噪比情况下性能不高。通过对Schmidl算法的改善,提出了一个新的改善算法。通过Matlab的模拟仿真表明,在信噪比较低时,新的算法定时估计性能优于Schmidl的算法。The great advantage of OFDM is that it is robust against frequency selective fading and can improve frequency utilization rate simultaneously. But OFDM is very sensitive to synchronization error, especially the symbol synchronization error. Traditionally, the MLE algorithm is an effective method for symbol timing estimation, but it has poor performance when there is ISI. The scheme based on preamble sequences proposed by Schmidl is efficient for the Timing Synchronization, but it provides bad performance under ISI and low SNR. A new method is proposed through improving the Schmidl＇s algorithm. It is demonstrated that the algorithm provides better performance than the Schmidl＇s when it is under low SNR.

关 键 词：正交频分复用 训练序列 符号定时估计 

分 类 号：TN11[电子电信—物理电子学] TN925