www.pudn.com > ls_mmse_lmmse.rar > SSER_compare.m, change:2008-05-29,size:5112b

```clc;
clear all;
%生成训练序列
%用BPSK调制
X=zeros(64,64);
d=rand(64,1);
for i=1:64
if(d(i)>=0.5)
d(i)=+1;
else
d(i)=-1;
end
end
for i=1:64
X(i,i)=d(i);
end
%计算出信道向量G
%信道特性
tau=[0.5 3.5];
for k=1:64
s=0;
for m=1:2
s=s+(exp(-j*pi*(1/64)*(k+63*tau(m))) * (( sin(pi*tau(m)) / sin(pi*(1/64)*(tau(m)-k)))));
end
g(k)=s/sqrt(64);
end
G=g';%信道向量
H=fft(G);% 频域
XFG=X*H;
n1=ones(64,1);
n1=n1*0.000000000000000001i;%加入复高斯白噪声
noise=awgn(n1,8);%设置SNR为8db
variance=var(noise);
N=fft(noise);
Y=XFG+N;

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% 求出G的自相关矩阵Rgg
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
gg=zeros(64,64);
for i=1:64
gg(i,i)=G(i);
end
gg_myu = sum(gg, 1)/64;
gg_mid = gg - gg_myu(ones(64,1),:);
sum_gg_mid= sum(gg_mid, 1);
Rgg = (gg_mid' * gg_mid- (sum_gg_mid'  * sum_gg_mid) / 64) / (64 - 1);

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
for n=1:6

SNR_send=3*n;
error_count_ls=0;%清空error_count..
error_count_mmse=0;%清空the error_count..
error_count_smmse=0;
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%求H_ls
%H_ls=inv(X)*Y;
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
H_ls=(inv(X)) * Y;
Hls=zeros(64,64);
for i=1:64
Hls(i,i)=H_ls(i);
end

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%求Hmmse
%H_mmse=F*Rgg*inv(Rgy)*Y;
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
u=rand(64,64);
F=fft(u)*inv(u);%DFT矩阵
I=eye(64,64);
Rgy=Rgg * F'* X';
Ryy=X * F * Rgg * F' *X' + variance * I;
for i=1:64
yy(i,i)=Y(i);
end
Gmmse=Rgy * inv(Ryy)* Y;
H_mmse=fft(Gmmse);
for i=1:64
Hmmse(i,i)=H_mmse(i);
end
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
u=rand(64,64);
F=fft(u)*inv(u);%DFT矩阵
I=eye(64,64);
Rhh=F*Rgg*F';
H_smmse=Rhh*inv(Rhh+(1/SNR_send)*I)*H_ls;
for i=1:64
Hsmmse(i,i)=H_smmse(i);
end
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
for c=1:1000
%生成随机序列
X=zeros(64,64);
d=rand(64,1);
for i=1:64
if(d(i)>=0.5)
d(i)=+1;
else
d(i)=-1;
end
end
for i=1:64
X(i,i)=d(i);
end
XFG=X*H;
n1=ones(64,1);
n1=n1*0.000000000000000001i;%加入复高斯白噪声
noise=awgn(n1,SNR_send);
variance=var(noise);
N=fft(noise);
Y=XFG+N;
%接收机
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% I:LS估计器的接收：
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
I=inv(Hls)* Y;
for k=1:64

if(real(I(k))>0)%判决
I(k)=1;
else
I(k)=-1;
end
end
for k=1:64
if(I(k)~=d(k))
error_count_ls=error_count_ls+1;
end
end
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% I:MMSE估计器的接收：
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
I=inv(Hmmse)* Y;
for k=1:64

if(real(I(k))>0)%判决
I(k)=1;
else
I(k)=-1;
end
end
for k=1:64
if(I(k)~=d(k))
error_count_mmse=error_count_mmse+1;
end
end
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% I:SMMSE估计器的接收：
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
I=inv(Hsmmse)* Y;
for k=1:64

if(real(I(k))>0)%判决
I(k)=1;
else
I(k)=-1;
end
end
for k=1:64
if(I(k)~=d(k))
error_count_smmse=error_count_smmse+1;
end
end
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
end
ser_ls(n)=error_count_ls/64000;
ser_mmse(n)=error_count_mmse/64000;
ser_smmse(n)=error_count_smmse/64000;
ser_ls
ser_mmse
ser_smmse
SNR(n)=SNR_send;

end;

%作图
semilogy(SNR,ser_mmse,'-vk');
axis([2,18,0.01,1]);
grid on;
xlabel('SNR in DB');
ylabel('Symbol Error Rate');
title('OFDM系统MMSE,LS和SMMSE算法的比较（SER）');

hold on;
semilogy(SNR,ser_ls,'-*b');
axis([2,18,0.01,1]);
grid on;
xlabel('SNR in DB');
ylabel('Symbol Error Rate');
title('OFDM系统MMSE,LS和SMMSE算法的比较（SER）');

hold on;
semilogy(SNR,ser_smmse,'-or');
axis([2,18,0.01,1]);
grid on;
xlabel('SNR in DB');
ylabel('Symbol Error Rate');
title('OFDM系统MMSE,LS和SMMSE算法的比较（SER）');
legend('MMSE算法','LS算法','SMMSE算法');
hold off

```