www.pudn.com > MIMO-OFDM(simulinkANDmatlab).rar > ofdm_fading.m, change:2001-11-29,size:5386b


% Program 4-2 
% ofdm_fading.m 
% 
% Simulation program to realize OFDM transmission system 
% (under one path fading) 
% 
% programmed by T.Yamamura and H.Harada 
% 
 
%********************** preparation part *************************** 
 
para=128;   % Number of parallel channel to transmit (points) 
fftlen=128; % FFT length 
noc=128;    % Number of carrier 
nd=6;       % Number of information OFDM symbol for one loop 
ml=2;       % Modulation level : QPSK 
sr=250000;  % Symbol rate 
br=sr.*ml;  % Bit rate per carrier 
gilen=32;   % Length of guard interval (points) 
ebn0=10;    % Eb/N0 
 
%******************* 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/(fftlen+gilen);  
 
% 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*(fftlen+gilen)*10; 
 
% 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=320;        
 
% 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; 
 
%************************** main loop part ************************** 
 
nloop=500;  % Number of simulation loops 
 
noe = 0;    % Number of error data 
nod = 0;    % Number of transmitted data 
eop=0;      % Number of error packet 
nop=0;      % Number of transmitted packet 
 
for iii=1:nloop 
 
%************************** transmitter ********************************* 
 
%************************** Data generation ****************************  
 
seldata=rand(1,para*nd*ml)>0.5;  %  rand : built in function 
 
%****************** Serial to parallel conversion *********************** 
 
paradata=reshape(seldata,para,nd*ml); %  reshape : built in function 
 
%************************** QPSK modulation *****************************  
 
[ich,qch]=qpskmod(paradata,para,nd,ml); 
kmod=1/sqrt(2); %  sqrt : built in function 
ich1=ich.*kmod; 
qch1=qch.*kmod; 
 
%******************* IFFT ************************ 
 
x=ich1+qch1.*i; 
y=ifft(x);      %  ifft : built in function 
ich2=real(y);   %  real : built in function 
qch2=imag(y);   %  imag : built in function 
 
%********* Gurad interval insertion ********** 
 
[ich3,qch3]= giins(ich2,qch2,fftlen,gilen,nd); 
fftlen2=fftlen+gilen; 
 
%********* Attenuation Calculation ********* 
 
spow=sum(ich3.^2+qch3.^2)/nd./para;  %  sum : built in function 
attn=0.5*spow*sr/br*10.^(-ebn0/10); 
attn=sqrt(attn); 
 
%********************** Fading channel ********************** 
 
% Generated data are fed into a fading simulator 
[ifade,qfade]=sefade(ich3,qch3,itau,dlvl,th1,n0,itnd1,now1,length(ich3),tstp,fd,flat); 
   
% Updata fading counter 
itnd1 = itnd1+ itnd0; 
 
%***************************  Receiver  ***************************** 
%***************** AWGN addition *********  
 
[ich4,qch4]=comb(ifade,qfade,attn); 
 
%****************** Guard interval removal ********* 
 
[ich5,qch5]= girem(ich4,qch4,fftlen2,gilen,nd); 
 
%******************  FFT  ****************** 
 
rx=ich5+qch5.*i; 
ry=fft(rx);   	% fft : built in function 
ich6=real(ry);	% real : built in function 
qch6=imag(ry);	% imag : built in function 
 
%***************** demoduration ******************* 
 
ich7=ich6./kmod; 
qch7=qch6./kmod; 
[demodata]=qpskdemod(ich7,qch7,para,nd,ml);    
 
%**************  Parallel to serial conversion  ***************** 
 
demodata1=reshape(demodata,1,para*nd*ml); 
 
%************************** Bit Error Rate (BER) **************************** 
 
% instantaneous number of error and data 
noe2=sum(abs(demodata1-seldata));  %  sum : built in function 
nod2=length(seldata);  %  length : built in function 
 
% cumulative the number of error and data in noe and nod 
noe=noe+noe2; 
nod=nod+nod2; 
 
% calculating PER 
if noe2~=0   
   eop=eop+1; 
else 
   eop=eop; 
end    
   eop; 
   nop=nop+1; 
    
 
fprintf('%d\t%e\t%d\n',iii,noe2/nod2,eop);  %  fprintf : built in function 
    
end 
 
%********************** Output result *************************** 
 
per=eop/nop; 
ber=noe/nod; 
 
fprintf('%f\t%e\t%e\t%d\t\n',ebn0,ber,per,nloop); 
fid = fopen('BERofdmfad.dat','a'); 
fprintf(fid,'%f\t%e\t%e\t%d\t\n',ebn0,ber,per,nloop); 
fclose(fid); 
 
%******************** end of file ***************************