Notes

AWGN
clear all;
close all;
clc;
num_bit=100000; %Signal length
max_run=20; %Maximum number of iterations for a single SNR
Eb=1; %Bit energy
SNRdB=0:1:9; %Signal to Noise Ratio (in dB)
SNR=10.^(SNRdB/10);

hand=waitbar(0,'Please Wait....');
for count=1:length(SNR) %Beginning of loop for different SNR
avgError=0;
No=Eb/SNR(count); %Calculate noise power from SNR

for run_time=1:max_run %Beginning of loop for different runs
waitbar((((count-1)*max_run)+run_time-1)/(length(SNRdB)*max_run));
Error=0;
data=randint(1,num_bit); %Generate binary data source
s=2*data-1; %Baseband BPSK modulation
N=sqrt(No/2)*randn(1,num_bit); %Generate AWGN
Y=s+N; %Received Signal
for k=1:num_bit %Decision device taking hard decision and deciding error
if ((Y(k)>0 && data(k)==0)||(Y(k)<0 && data(k)==1))
Error=Error+1;
end
end

Error=Error/num_bit; %Calculate error/bit
avgError=avgError+Error; %Calculate error/bit for different runs
end
BER_sim(count)=avgError/max_run; %Calculate BER for a particular SNR
end
BER_th=(1/2)*erfc(sqrt(SNR)); %Calculate analytical BER
close(hand);

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