function h=rey(Nt,Nr)%瑞利衰減信道矩陣模型，Nt為發射天線個數，Nr為接收天線個數
h=zeros(Nr,Nt);
R=eye(Nr*Nt);                                               
X=randn(Nr*Nt,1)/sqrt(2)+j*randn(Nr*Nt,1)/sqrt(2);         
h=reshape(R*X,Nr,Nt);