中文说明：
瑞利衰落信道，是一种无线电信号传播环境的统计模型。这种模型假设信号通过无线信道之后，其信号幅度是随机的，即“衰落”，并且其包络服从瑞利分布。这一信道模型能够描述由电离层和对流层反射的短波信道，以及建筑物密集的城市环境。
English Description：
Rayleigh fading channel is a statistical model of radio signal propagation environment. This model assumes that the signal amplitude is random after passing through the wireless channel, namely "fading", and its envelope obeys Rayleigh distribution. This channel model can describe the shortwave channel reflected by ionosphere and troposphere, and the urban environment with dense buildings.