SNR=[-5:1:10];
snr = 10.^(SNR/10); 
result_qpsk = fopen('result_qpsk_ViterbiHard_rayleigh.txt','r');
BER_qpsk = fscanf(result_qpsk,'%g');
fclose(result_qpsk);
semilogy(SNR,BER_qpsk,'r-*')
xlabel('SNR [dB]')
ylabel('BER')
hold on
grid on
SNR=[-5:1:10];
snr = 10.^(SNR/10); 
for k = 1:length(SNR)
theoretical(k) = 1/2*(1-sqrt(snr(k)/(1+snr(k))));
end
semilogy(SNR,theoretical,'b-o')
hold on
grid on