N_3_Repetetion.m

EbNodB = 6;
R = 1/3;                            %N=3 Reptition Code (1/3 bits/symbol)%
EbNo = 10^(EbNodB/10);              
sigma = sqrt(1/(2*R*EbNo));

%%BER_th = 0.5*erfc(sqrt(EbNo));


k = 1;                              %Number of Bits of message per block
n = 3;                              %Number of codeword bits   

Nerrs = 0; Nblocks = 100000;
for i = 1 : Nblocks
   msg = randi([0 1],1,k);           %generate random message
   %Encoding here
   cword = [msg msg msg];
      
   s = 1 - 2 * cword;                 %BPSK symbols
   r = s + sigma * randn(1,n);        %AWGN Channel
   %Hard-Decision Decoding here
   b = ( r < 0 );                     %threshold at zero
   if(sum(b) > 1)
       msg_cap1 = 1;
   else 
       msg_cap1 = 0;
   end
   
   %Soft-Decision Decoding here
   if(sum(r) < 0)
       msg_cap2 = 1;
   else 
       msg_cap2 = 0;
   end

   Nerrs = Nerrs + sum(msg ~= msg_cap2);
end

BER_sim = Nerrs/(k*Nblocks);

disp([EbNodB BER_sim Nerrs k*Nblocks]);