i want to plot 4 craves but my code only plot three

Nt = [1 1 4 4];
Nr = [1 4 1 4];

gammaBar = -10:1:0;
SNR = 10 .^(gammaBar/10);
H = sqrt(1/2) * (randn+1j*randn);

for idx = 1:1:length(SNR)
    cdf1(idx) = log2(det((eye(Nr(1)))+((SNR(idx)/Nt(1))*abs(H)*(abs(H')))));
    cdf2(idx) = log2(det((eye(Nr(2)))+((SNR(idx)/Nt(2))*abs(H)*(abs(H')))));
    cdf3(idx) = log2(det((eye(Nr(3)))+((SNR(idx)/Nt(3))*abs(H)*(abs(H')))));
    cdf4(idx) = log2(det((eye(Nr(4)))+((SNR(idx)/Nt(4))*abs(H)*(abs(H')))));
end

figure(1)

plot(gammaBar, cdf1, gammaBar, cdf2, gammaBar, cdf3,gammaBar,cdf4)

xlabel('SNR in dB');
ylabel('Ergodic Channel Capacity');

Answer 1

[Voss]

cdf1 and cdf4 are almost the same:

Nt = [1 1 4 4];
Nr = [1 4 1 4];

gammaBar = -10:1:0;
SNR = 10 .^(gammaBar/10);
H = sqrt(1/2) * (randn+1j*randn);

for idx = 1:1:length(SNR)
    cdf1(idx) = log2(det((eye(Nr(1)))+((SNR(idx)/Nt(1))*abs(H)*(abs(H')))));
    cdf2(idx) = log2(det((eye(Nr(2)))+((SNR(idx)/Nt(2))*abs(H)*(abs(H')))));
    cdf3(idx) = log2(det((eye(Nr(3)))+((SNR(idx)/Nt(3))*abs(H)*(abs(H')))));
    cdf4(idx) = log2(det((eye(Nr(4)))+((SNR(idx)/Nt(4))*abs(H)*(abs(H')))));
end

figure(1)

max(abs(cdf1-cdf4))

ans = 9.2287e-16

plot(gammaBar, cdf1, '-x', gammaBar, cdf2, gammaBar, cdf3, gammaBar, cdf4, '--o')

xlabel('SNR in dB');
ylabel('Ergodic Channel Capacity');
legend()