stbc1126.m

是自己自创的好程序

clear all;
close all;
tic;
for trial=1:1000,
snr=30;
subchannel=16;
ws=hadamard(8)/sqrt(8);
Nt=2;
x=randint(1,128,[0,3]);
chann_h1=(ones(1,64)+sqrt(-1)*ones(1,64))/sqrt(2);
h1=diag(kron(chann_h1,ones(1,2)));
chann_h2=(ones(1,64)+sqrt(-1)*ones(1,64))/sqrt(2);
h2=diag(kron(chann_h2,ones(1,2)));
mod_sig=qammod(x,4)./sqrt(2);
X1=mod_sig(1:2:end)*sqrt(1/2);
X2=mod_sig(2:2:end)*sqrt(1/2);
trans_two=zeros(2,128);
for i=1:64
    t_x1=X1(i);
    t_x2=X2(i);
    trans_two(1,(i-1)*2+1:i*2)=[t_x1,-conj(t_x2)];
    trans_two(2,(i-1)*2+1:i*2)=[t_x2,conj(t_x1)];
end
transmit_two=zeros(2,128);
transmit_two(1,:)=h1*trans_two(1,:).';
transmit_two(2,:)=h2*trans_two(2,:).';
trans_signal=zeros(1,128);
for ant=1:Nt
    trans_signal=trans_signal+transmit_two(ant,:);
end
trans_signal=awgn(trans_signal,snr);
Re_h1=diag(h1);
Re_h2=diag(h2);
Re_x=zeros(1,128);
for i=1:64
    R1=trans_signal((i-1)*2+1);
    R2=trans_signal(i*2);
    hh1=Re_h1((i-1)*2+1);
    hh2=Re_h2((i-1)*2+1);
    beta_X1=conj(hh1)*R1+hh2*conj(R2);
    beta_X2=conj(hh2)*R1-(hh1)*conj(R2);
    Re_x(1,(i-1)*2+1:2*i)=[beta_X1,beta_X2];
end
demod_Qpsk=qamdemod(Re_x,4);
%add the computer SNR
first_Rx=complex(abs(real(Re_x)),abs(imag(Re_x)));
mean_value=mean(first_Rx);
power_value=abs(mean_value).^2;
var_noise=var(first_Rx);
Current_SNR=10*log10(power_value/var_noise);
%add the computer SNR.
%x-demod_Qpsk
% fs=2e6;
% Nfft=256;
% fdelta=fs/Nfft
%     Pow=[0 -4 -8];  %heavy multipath
%     Delay=[0 1.5 4]*1e-6;
%     hh=10.^(Pow/20);
%     norm_h=hh./norm(hh);
%     h=norm_h.*exp(sqrt(-1)*2*pi*rand(1,length(Pow)));
%     for k=1:128,
%         f=(k-1)*fdelta;
%         H(k)=h*exp(sqrt(-1)*2*pi*Delay'*f);
%         g(k)=norm(H(k));
%     end;
%     plot(20*1og10(g));
SNR_frame(trial)=Current_SNR;
end;
toc;