clear all; close all;clc;
num_bit=100000;
max_run=20;
Eb=1;
SNRdB=0:1:9;
SNR=10.^(SNRdB/10);

hand=waitbar(0,'Xin hay doi ....');
for count=1:length(SNR)
    avgError=0;
    No=Eb/SNR(count);
  
    for run_time=1:max_run
    waitbar((((count-1)*max_run)+run_time-1)/(length(SNRdB)*max_run));
    Error=0;
   
    data=randint(1,num_bit);
    s=2*data-1;
    N=sqrt(No/2)*randn(1,num_bit);
   
    Y=s+N;
   
    for k=1:num_bit
        if ((Y(k)>0 && data(k)==0) || (Y(k)<0 && data(k)==1))
            Error=Error+1;
        end
    end
    Error=Error/num_bit;
    avgError=avgError+Error;
end
    BER_sim(count)=avgError/max_run;
end
BER_th=(1/2)*erfc(sqrt(SNR));
close(hand);

semilogy(SNRdB,BER_th,'k');
hold on
semilogy(SNRdB,BER_sim,'k*');
legend('Theoretical','Simulation',3);
axis([min(SNRdB) max(SNRdB) 10^(-5) 1]);
hold off