ergodic_capacity_cdf.m

% Ergodic Capacity CDF.m
clear all, close all;
SNR_dB=10; SNR_linear=10.^(SNR_dB/10.);
N_iter=50000; sq2=sqrt(0.5); grps=['b:'; 'b-'];
for Icase=1:2
if Icase==1, nT= 2; nR= 2; % 2x2
else nT= 4; nR= 4; % 4x4
end
n= min(nT,nR); I= eye(n);
for iter= 1:N_iter
H=sq2*(randn(nR,nT)+j*randn(nR,nT));
C(iter)= log2(real(det(I+SNR_linear/nT*H'*H)));
end
[PDF,Rate]= hist(C,50);
PDF= PDF/N_iter;
for i= 1:50
CDF(Icase,i)= sum(PDF([1:i]));
end
plot(Rate,CDF(Icase,:),grps(Icase,:)); hold on
end
xlabel('Rate[bps/Hz]'); ylabel('CDF');
axis([1 18 0 1]); grid on; set(gca,'fontsize',10);
legend('{\it N_T}= {\it N_R}= 2','{\it N_T}= {\it N_R}= 4');