www.pudn.com > MODULATION.RAR > oqpsk_fading.m, change:2001-11-30,size:4790b


% Program 3-12 
% oqpsk_fading.m 
% 
% Simulation program to realize OQPSK transmission system 
% (under one path fading) 
% 
% Programmed by H.Harada and T.Yamamura 
% 
 
%******************** Preparation part ************************************* 
 
sr=256000.0; % Symbol rate 
ml=2;        % 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  
ebn0=10;     % Eb/N0 
IPOINT=8;    % Number of oversamples 
 
%************************* 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  
 
%******************* Fading initialization ******************** 
% If you use fading function "sefade", you can initialize all of parameters. 
% Otherwise you can comment out the following initialization. 
% The detailed explanation of all of valiables are mentioned in Program 2-8. 
 
% Time resolution 
 
tstp=1/sr/IPOINT;  
 
% Arrival time for each multipath normalized by tstp 
% If you would like to simulate under one path fading model, you have only to set  
% direct wave. 
 
itau = [0]; 
 
% Mean power for each multipath normalized by direct wave. 
% If you would like to simulate under one path fading model, you have only to set  
% direct wave. 
dlvl = [0]; 
 
% Number of waves to generate fading for each multipath. 
% In normal case, more than six waves are needed to generate Rayleigh fading 
n0=[6]; 
 
% Initial Phase of delayed wave 
% In this simulation four-path Rayleigh fading are considered. 
th1=[0.0]; 
 
% Number of fading counter to skip  
itnd0=nd*IPOINT; 
 
% Initial value of fading counter 
% In this simulation one-path Rayleigh fading are considered. 
% Therefore one fading counter are needed. 
   
itnd1=[1000]; 
 
% Number of directwave + Number of delayed wave 
% In this simulation one-path Rayleigh fading are considered 
now1=1;         
 
% Maximum Doppler frequency [Hz] 
% You can insert your favorite value 
fd=160;        
 
% You can decide two mode to simulate fading by changing the variable flat 
% flat     : flat fading or not  
% (1->flat (only amplitude is fluctuated),0->nomal(phase and amplitude are fluctutated) 
flat =1; 
 
%******************** START CALCULATION ************************************* 
 
nloop=200;  % 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;  % rand: built in function 
 
%*************************** OQPSK Modulation ********************************   
  
    [ich,qch]=qpskmod(data1,1,nd,ml); 
    [ich1,qch1]=compoversamp(ich,qch,length(ich),IPOINT); 
    ich21=[ich1 zeros(1,IPOINT/2)]; 
    qch21=[zeros(1,IPOINT/2) qch1]; 
    [ich2, qch2]=compconv(ich21,qch21,xh);  
  
%**************************** Attenuation Calculation *********************** 
 
    spow=sum(ich2.*ich2+qch2.*qch2)/nd;  % sum: built in function 
    attn=0.5*spow*sr/br*10.^(-ebn0/10); 
    attn=sqrt(attn);  % sqrt: built in function 
    
%********************** Fading channel ********************** 
  
  % Generated data are fed into a fading simulator 
    [ifade,qfade]=sefade(ich2,qch2,itau,dlvl,th1,n0,itnd1,now1,length(ich1),tstp,fd,flat); 
   
  % Updata fading counter 
    itnd1 = itnd1+ itnd0; 
 
%********************* Add White Gaussian Noise (AWGN) ********************** 
     
    [ich3,qch3]= comb(ifade,qfade,attn);% add white gaussian noise 
	[ich4,qch4]= compconv(ich3,qch3,xh2); 
 
    syncpoint=irfn*IPOINT+1; 
    ich5=ich4(syncpoint:IPOINT:length(ich4)); 
    qch5=qch4(syncpoint+IPOINT/2:IPOINT:length(qch4)); 
         
%**************************** OQPSK Demodulation ***************************** 
    
    [demodata]=qpskdemod(ich5,qch5,1,nd,ml); 
 
%************************** Bit Error Rate (BER) **************************** 
 
    noe2=sum(abs(data1-demodata));  % sum: built in function 
    nod2=length(data1);  % length: built in function 
    noe=noe+noe2; 
    nod=nod+nod2; 
 
    fprintf('%d\t%e\n',iii,noe2/nod2);  % fprintf: built in function 
 
end % for iii=1:nloop     
 
%********************** Output result *************************** 
 
ber = noe/nod; 
fprintf('%d\t%d\t%d\t%e\n',ebn0,noe,nod,noe/nod);  % fprintf: built in function 
fid = fopen('BERoqpskfad.dat','a'); 
fprintf(fid,'%d\t%e\t%f\t%f\t\n',ebn0,noe/nod,noe,nod);  % fprintf: built in function 
fclose(fid); 
 
 
%******************** end of file ***************************