% Program 3-21
% qam16
%
% Simulation program to realize 16QAM transmission system
%
% Programmed by H.Harada and R.Funada
%
%******************** preparation part *************************************
sr=256000.0; % Symbol rate
ml=4; % ml:Number of modulation levels (BPSK:ml=1, QPSK:ml=2, 16QAM:ml=4)
br=sr .* ml; % Bit rate
nd = 1000; % Number of symbols that simulates in each loop
snr_in_dB=9 % Eb/N0
IPOINT=8; % Number of oversamples
SNR=exp(snr_in_dB*log(10)/10);
%********************** Filter initialization **************************
% irfn=21; % Number of taps
% alfs=0.5; % Rolloff factor
% [xh] = hrollfcoef(irfn,IPOINT,sr,alfs,1); %Transmitter filter coefficients
% [xh2] = hrollfcoef(irfn,IPOINT,sr,alfs,0); %Receiver filter coefficients
%************************** START CALCULATION *******************************
nloop=100; % Number of simulation loops
noe = 0; % Number of error data
nod = 0; % Number of transmitted data
for iii=1:nloop
%*************************** Data generation ********************************
data1=rand(1,nd*ml)>0.5;
%*************************** 16QAM Modulation ********************************
[ich,qch]=qammod(data1,1,nd,ml);
% [ich1,qch1]= compoversamp(ich,qch,length(ich),IPOINT);
% [ich2,qch2]= compconv(ich1,qch1,xh);
%**************************** Attenuation Calculation ***********************
%
% spow=sum(ich2.*ich2+qch2.*qch2)/nd;
% attn=0.5*spow*sr/br*10.^(-ebn0/10);
% attn=sqrt(attn);
code_rate=1;
E=1/4;
sigma=E/sqrt(2*SNR*code_rate); % sigma, standard deviation of noise
for i=1:nd,
ich1(i)=ich(i)+Gngauss(sigma); % if the source output is "0"
qch1(i)=qch(i)+Gngauss(sigma); % if the source output is "1"
end;
%********************** Fading channel **********************
% Generated data are fed into a fading simulator
% [ifade,qfade]=sefade(ich2,qch2,itau,dlvl,th1,n0,itnd1,now1,length(ich2),tstp,fd,flat);
% Updata fading counter
% itnd1 = itnd1+ itnd0;
%********************* Add White Gaussian Noise (AWGN) **********************
% [ich3,qch3]= comb(ich2,qch2,attn);% add white gaussian noise
% [ich4,qch4]= compconv(ich3,qch3,xh2);
% sampl=irfn*IPOINT+1;
% ich5 = ich4(sampl:IPOINT:length(ich4));
% qch5 = qch4(sampl:IPOINT:length(ich4));
%**************************** 16QAM Demodulation *****************************
[demodata]=qamdemod(ich1,qch1,1,nd,ml);
%******************** Bit Error Rate (BER) ****************************
noe2=sum(abs(data1-demodata));
nod2=length(data1);
noe=noe+noe2;
nod=nod+nod2;
% fprintf('%d\t%e\n',iii,noe2/nod2);
end % for iii=1:nloop
%********************** Output result ***************************
ber = noe/nod
% fprintf('%d\t%d\t%d\t%e\n',ebn0,noe,nod,noe/nod);
% fid = fopen('BERqam.dat','a');
% fprintf(fid,'%d\t%e\t%f\t%f\t\n',ebn0,noe/nod,noe,nod);
% fclose(fid);
%******************** end of file ***************************