www.pudn.com > MODULATION.RAR > bpsk_fading.m, change:2001-11-30,size:4484b


% Program 3-2 
% bpsk_fading.m 
% 
% Simulation program to realize BPSK transmission system 
% (under one path fading) 
% 
% Programmed by H.Harada and T.Yamamura, 
% 
 
%******************** Preparation part ********************** 
 
sr=256000.0; % Symbol rate 
ml=1;        % Number of modulation levels 
br=sr.*ml;   % Bit rate (=symbol rate in this case) 
nd = 100;    % Number of symbols that simulates in each loop 
ebn0=10;     % Eb/N0 
IPOINT=8;    % Number of oversamples 
 
%******************* Filter initialization ******************** 
 
irfn=21;     % Number of filter 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*100; 
 
% 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=1000;  % Number of simulation loops 
 
noe = 0;    % Number of error data 
nod = 0;    % Number of transmitted data 
 
for iii=1:nloop 
	 
%******************** Data generation ***********************  
 
    data=rand(1,nd)>0.5;  % rand: built in function 
 
%******************** BPSK Modulation ***********************   
 
    data1=data.*2-1; 
	[data2] = oversamp( data1, nd , IPOINT) ; 
	data3 = conv(data2,xh);  % conv: built in function 
 
 
%****************** Attenuation Calculation ***************** 
	 
    spow=sum(data3.*data3)/nd; 
	attn=0.5*spow*sr/br*10.^(-ebn0/10); 
	attn=sqrt(attn); 
    
%********************** Fading channel ********************** 
 
  % Generated data are fed into a fading simulator 
  % In the case of BPSK, only Ich data are fed into fading counter 
  [ifade,qfade]=sefade(data3,zeros(1,length(data3)),itau,dlvl,th1,n0,itnd1,now1,length(data3),tstp,fd,flat); 
   
  % Updata fading counter 
  itnd1 = itnd1+ itnd0; 
 
 
%************ Add White Gaussian Noise (AWGN) *************** 
	 
    inoise=randn(1,length(ifade)).*attn;  % randn: built in function 
	data4=ifade+inoise; 
	data5=conv(data4,xh2);  % conv: built in function 
 
	sampl=irfn*IPOINT+1; 
	data6 = data5(sampl:8:8*nd+sampl-1); 
     
%******************** BPSK Demodulation ********************* 
	 
    demodata=data6 > 0; 
 
%******************** Bit Error Rate (BER) ****************** 
	 
    % count number of instantaneous errors 
    noe2=sum(abs(data-demodata));  % sum: built in function 
	 
    % count number of instantaneous transmitted data 
    nod2=length(data);  % length: built in function 
	 
    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('BERbpskfad.dat','a'); 
fprintf(fid,'%d\t%e\t%f\t%f\t\n',ebn0,noe/nod,noe,nod); 
fclose(fid); 
 
%******************** end of file ***************************