ofdm matlab代码

% 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 ***************************