多径衰落信道下OFDM时间同步算法的研究

A Novel Timing Synchronization Algorithm Based on Energy Difference over Multi-path Fading Channel

为了论述一种适于多径衰落信道的OFDM时间同步新方法:首先,将接收的信号乘上其共轭得到信号的能量;然后,进行间隔为OFDM数据符号长度减去循环前缀(CP)长度的能量差分得到相关函数;最后,联合多个符号的块采样进行同步估计。由于利用了信号能量的差分关系,使得同步峰更加明显,再联合多个符号的估计,更加强了同步的稳定性。在多径衰落信道下进行仿真,结果表明,不但能获到较好的符号定时同步性能,而且还消除了频偏对于符号定时的影响。

A novel time synchronization algorithm suited for multi -path fading channel is proposed. First, the received signals are multiplied by the conjugate to acquire the signal energy, then the correlation function is acquired by carrying out the energy differential operation with the interval of the length of OFDM data symbol part minus the length of cyclic prefix （CP） , finally timing synchronization is estimated by uniting the multiple symbols sampling. Because of taking advantage of differential operation of the signal energy, the synchronous peak is clearer, and the estimation of multiple symbols strengthens the stability of synchronization. The simulation shows that the proposed algorithm can acquire a better performance of symbol timing, and remove the impact of frequency offset.