这是一个瑞利衰落信道的源程序，其中包含C和Matlab两种方式实现-This is a Rayleigh fading channel of the source code, including C and Matlab in two ways to achieve

要求对有3条固定路径的AWGN多径信道中的QPSK系统进行BER性能仿真，并与在理想的AWGN信道中同样系统的BER性能进行比较。熟悉瑞利平坦衰落、莱斯平坦衰落与频率选择性衰落的特点，比较这些衰落信道的误码率。-Required to have three fixed-path AWGN multipath channels of QPSK system BER performance simulation, and in an ideal AWGN channel with the same