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