说明：  OFDM程序，这么安排矩阵的目的是为了构造共轭对称矩阵 共轭对称矩阵的特点是 在ifft/fft的矢量上 N点的矢量 在0，N/2点必须是实数 一般选为0 1至N/2点 与 （N/2）+1至N-1点关于N/2共轭对称
( BPSK simulation using a carrier cosine wave with ISI clc close all clear all figure(1) n=160 for i=1:n data(i)= 2*round(rand)-1 end create modulated BPSK signal first expand the bit stream exdata=[] for i=1:length(data) for rep=1:5 exdata= [exdata data(i)] end end ts=.1 t=1:ts:80.9 carrier=cos(pi*t) multiply expanded bitstream by cosine wave with carrier frequency this is the BPSK that is to be transmitted over the channel bpsk=carrier.*exdata bpsk=[bpsk(length(bpsk)-1) bpsk(length(bpsk)) bpsk] plot(bpsk) generating the noise p=rand(1,800)*2*pi p=rand*2*pi snr=10 r=sqrt(-1*(1/snr*log(1- rand))) no = 5*(r.* exp(j*p)) no = (r.* exp(j*p)) value of alpha al=rand+j*rand al=1 Spreading channel with the alpha as the variable for k=5:5:795 for l = 1:5 al=round(rand)+j*round(rand) rec(k+l)=bpsk(k+l)+al*bpsk(k-5+l) end end rxdata=rec+ no begin demodulation first multiply recie)