Single/Multipath Channel Model Verificaiton EbNo vs. BER/SER under AWGN BPSK vs. QPSK Theory vs.

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				% File Name: qpsk.m
				% Function: qpsk simulation
				% Author: 
				% Date: 11.28
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				clear all;
				%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% Preparation part %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
				
				sr=256000.0; % symbol rate
				ml=2;        % number of modulation levels (QPSK:ml=2)
				br=sr .* ml; % bit rate
				nd = 1000;   % number of symbols that simulates in each loop
				Eb_N0=0:1:30;% Eb/N0
				nloop=500;    % number of simulation loops
				
				for i=1:length(Eb_N0)
				    
				    noe = 0;    % number of error data
				    nod = 0;    % number of transmitted data
				    soe = 0;    % number of error symbol
				    sos = 0;    % number of transmitted symbol
				    totalb = 0;
				    totals = 0;
				    
				    for ii=1:nloop
				    
				%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% Data Generation %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%  
					
				    data1=rand(1,nd*ml)>0.5;
				    
				%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% QPSK Modulation %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%  
				
				    [ich,qch]=qpskmod(data1,nd,ml);
				     
				%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% Attenuation Calculation %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
					
				    spow=sum(ich.*ich+qch.*qch)/nd;  
					attn=0.5*spow*sr/br*10.^(-Eb_N0(i)/10);
					attn=sqrt(attn); 
				    
				%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% AWGN %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
					
				    [ich2,qch2]= qpskawgn(ich,qch,attn);
				        
				%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% QPSK Demodulation %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
				
				    [demodata]=qpskdemod(ich2,qch2,nd,ml);
				
				%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% BER/SER %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
				
				    noe2=sum(abs(data1-demodata));
					nod2=length(data1); 
					noe=noe+noe2;
					nod=nod+nod2;
					totalb = totalb + noe/nod;
				    
				    soe = soe + qpskser(data1,demodata,ml);
				    sos = sos + length(data1) ./ ml;
				    totals = totals + soe/sos;
				    
				    end % for ii=1:nloop   
				    
				    Avg_BER(i) = totalb/nloop;
				    Theory(i) = (1/2) * erfc(sqrt(10.^(Eb_N0(i)/10)));
				    SER(i) = totals/nloop;
				    SNR(i) = 10*log10(10^(Eb_N0(i)/10) ./ ml);
				end % Eb_N0=0:1:10
				
				%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% Output EbN0 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
				%figure;clf;
				% semilogy(Eb_N0,Avg_BER,'b-o');
				% title('QPSK EbN0 vs. BER/SER (AWGN)'); 
				% xlabel('Eb/N0(dB)');
				% ylabel('BER/SER');
				% grid on;
				% hold on;
				%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% Theorectical BER %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
				
				% semilogy(Eb_N0,Theory,'r-*');
				%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
				% semilogy(Eb_N0,SER,'r-*');
				%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% Output SNR %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
				
				figure;clf;
				semilogy(SNR,Avg_BER,'b-o');
				title('QPSK SNR vs. BER/SER (AWGN)'); 
				xlabel('SNR(dB)');
				ylabel('BER/SER');
				grid on;
				hold on;
				% 
				% semilogy(SNR,SER,'r-*');
				
				%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% end %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%