OFDM 系统信道估计LS方法和LMMSE方法的性能比较。由于LMMSE利用了信道的相关性信息，它的性能比LS好。-OFDM system channel estimation performance comparison of the LS method and the LMMSE method. Due to the the LMMSE use of relevant information of the channel, its performance is better than the