无线移动通信系统仿真（帮忙看看程序对吗）

10条路径，相邻两条路径的时延差为一个采样间隔，功率满足负指数分布，整个无线信
道满足Ralyeigh分布，用MATLAB实现。
chan = rayleighchan(1/15000,500);  
x1=ones(1,4000);
x2=[0,ones(1,3999)];
x3=[0,0,ones(1,3998)];
x4=[0,0,0,ones(1,3997)];
x5=[0,0,0,0,ones(1,3996)];
x6=[0,0,0,0,0,ones(1,3995)];
x7=[0,0,0,0,0,0,ones(1,3994)];
x8=[0,0,0,0,0,0,0,ones(1,3993)];
x9=[0,0,0,0,0,0,0,0,ones(1,3992)];
x10=[0,0,0,0,0,0,0,0,0,ones(1,3991)];
y = filter(chan,x1+x2+x3+x4+x5+x6+x7+x8+x9+x10);  
fs = 15000;  
Y = fft(y,4096);  
Y = fftshift(abs(Y));  
plot([-2048:2047]*fs/4096,YY)  
axis([-1000 1000 min(YY) max(YY)])

初学，欢迎指导