对3条固定路径的AWGN多径信道中的QPSK系统进行BER性能仿真（不同p和delay 的取值来分别定义莱斯（瑞利）平坦衰落信道、莱斯（瑞利）频率选择性衰落信道).-For three fixed-path multipath AWGN channel of the QPSK system BER performance simulation (different values for p and the delay are defined Rice (Rayleigh) flat fading

Though the total channel is a frequency selective channel, the channel experienced by each subcarrier in an OFDM system is a flat fading channel with each subcarrier experiencing independent Rayleigh fading.