capacity_2.m

本代码给出基于MIMO系统下的系统容量分析

clear
%%%%%%%%%%%%%%%%%%%%%%%%%%% 2x2
Nt=2;
Nr=2;
max_snr=30;
c22=zeros(1,max_snr+1);
H=RayleighCH(Nr,Nt);
w=H*H';
u=eye(Nr,Nr);
for snr_in_db=0:max_snr
    SNR=10^(snr_in_db/10);
v=u+w/Nt*SNR;
delt=det(v);
c22(snr_in_db+1)=log2(delt);
end
%%%%%%%%%%%%%%%%%%%%%%%%%% 2x1
Nt=2;
Nr=1;
max_snr=30;
c21=zeros(1,max_snr+1);
h=randn(Nr*Nt,1)/sqrt(2)+j*randn(Nr*Nt,1)/sqrt(2);
w1=(abs(h(1))^2+abs(h(2))^2);
for snr_in_db=0:max_snr
    SNR=10^(snr_in_db/10);
c21(snr_in_db+1)=log2(1+SNR*w1/2);
end

%%%%%%%%%%%%%%%%%%%%%%%% 1x2
Nt=1;
Nr=2;
max_snr=30;
c12=zeros(1,max_snr+1);
h=randn(Nr*Nt,1)/sqrt(2)+j*randn(Nr*Nt,1)/sqrt(2);
w=(abs(h(1))^2+abs(h(2))^2);
for snr_in_db=0:max_snr
    SNR=10^(snr_in_db/10);
c12(snr_in_db+1)=log2(1+SNR*w);
end
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%siso
Nt=1;
Nr=1;
max_snr=30;
c11=zeros(1,max_snr+1);
h=randn(Nr*Nt,1)/sqrt(2)+j*randn(Nr*Nt,1)/sqrt(2);
w=(abs(h)^2);
for snr_in_db=0:max_snr
    SNR=10^(snr_in_db/10);
c11(snr_in_db+1)=log2(1+SNR*w);
end
plot(0:max_snr,c22,'-*',0:max_snr,c21,'b',0:max_snr,c12,'-+',0:max_snr,c11,'r--')
legend('2Tx2Rx','2Tx1Rx','1Tx2Rx','1Tx1Rx')
xlabel('SNR (dB)')
ylabel('信道容量 (b/s/Hz)')