ofdm.m

ofdm ifft/fft仿真

clear,clc;


SNR=10;
fl=128;
Ns=6;
para=128;
sr=250000;
br=sr.*2;
gl=32;

Signal=rand(1,para*Ns*2)>0.5;

for i=1:para
    for j=1:Ns*2
        SigPara(i,j)=Signal(i*j);
    end
end

for j=1:Ns
    ich(:,j)=SigPara(:,2*j-1);
    qch(:,j)=SigPara(:,2*j);
end
kmod=1./sqrt(2);
ich1=ich.*kmod;
qch1=qch.*kmod;
x=ich1+qch1.*sqrt(-1);
y=ifft(x);
ich2=real(y);
qch2=imag(y);

ich3=[ich2(fl-gl+1:fl,:);ich2];
qch3=[qch2(fl-gl+1:fl,:);qch2];

ich4=reshape(ich3,1,(fl+gl)*Ns);
qch4=reshape(qch3,1,(fl+gl)*Ns);
TrData=ich4+qch4.*sqrt(-1);
ReData=awgn(TrData,SNR,'measured');

idata=real(ReData);
qdata=imag(ReData);
idata1=reshape(qdata,fl+gl,Ns);
qdata1=reshape(qdata,fl+gl,Ns);
idata2=idata1(gl+1:gl+fl,:);
qdata2=qdata1(gl+1:gl+fl,:);

Rex=idata2+qdata2*sqrt(-1);
ry=fft(Rex);
ReIChan=real(ry);
plot(ReIChan)
ReQChan=imag(ry);
ReIChan=ReIChan/kmod;
ReQChan=ReQChan/kmod;

for j=1:Ns
    RePara(:,2*j-1)=ReIChan(:,j);
    RePara(:,2*j)=ReQChan(:,j);
end
ReSig=reshape(RePara,1,para*Ns*2);
ReSig=ReSig>0.5;

figure(2)
subplot(2,1,1),stem(ReSig(1:20)),grid;subplot(2,1,2),stem(Signal(1:20)),grid