hold off
subplot(2,2,1)
semilogy(G(:,2),G(:,5),'k-')
hold on
xlabel 'SNR (dB)'
ylabel 'BER'
title 'REPLACE THIS TITLE'

axis([0 20 1e-6 1e0]);

xlabel 'SNR (dB)'
ylabel 'BER'

x = 1;
y = 0.5e-4;

text(x,y, '\_\_\_\_ known channel');
