多径衰落信道下OFDM系统定时同步优化

An optimized estimation method for OFDM system under multipath fading channels

在多径环境下,正交频分复用(OFDM)系统对第1径的寻找是解决定时同步的关键,多数算法将最强径当作第1径,使得定时同步向后延迟,造成严重的ISI.本文在PN训练定时同步的基础上,通过寻找滑动求和值的第1个下降沿来确定第1径的位置.仿真结果证明了本算法的优越性,同时在第1径不为最强径的情况下算法也能得到较好效果.

In the multipath channels,determining the first path is one of the key steps of OFDM system,but most previous methods assumed the strongest path as the first path,this makes the timing delay and introduces serious ISI.In the paper a new algorithm based on the timing synchronization algorithm using PN sequence is proposed.The timing of the first path is determined by detecting the first falling edge of the moving summation of the correlation results.Simulation results show that the performance of the new scheme is much better than the conventional synchronization algorithms in multipath environment.