改进的基于叠加导频序列的OFDM系统的信道估计方法

A Modified Channel Estimation Method for OFDM Systems Based on Superimposed Pilots

针对正交频分复用(OFDM)系统在时变信道中的应用,提出了一种简单有效的信道估计方法.在这种方法中,假设数据以包为单位进行发送,导频序列采用叠加(superimposed)的方式和数据序列相结合,得到对应于一个数据包内每一帧OFDM信号的信道冲激响应之后,在这个数据包内对这些信道冲激响应进行加权平均,从而提高信道估计的精度.该方法不需占用无线传输中宝贵的频谱资源,且适用于时变无线信道.最后给出仿真结果,以说明方法的有效性.

For applications of orthogonal frequency division multiplexing （OFDM） in time-variant channels, a simple but efficient method for channel estimation is proposed. In this method, the data are assumed to be transmitted in packets while the pilot sequences and data sequences are combined by superimposing. After getting the channel impulse responses corresponding to each frame of OFDM signals in a packet, they are weightedly averaged over the packet. In such a way the accuracy of channel estimation is improved. This method can be applied to the time variant wireless channels without occupying any spectrum resources. Computer simulation results are also given to show the efficiency of the present method.