OFDM Simulation In MAtlab

parisa66 said:

sure

5.1 OFDM Transmission

%DVB-T2KTransmission
%Theavailablebandwidthis8MHz
%2Kisintendedformobileservices
clearall;
closeall;
%DVB-TParameters
Tu=224e-6; %usefulOFDMsymbolperiod
T=Tu/2048; %basebandelementaryperiod
G=0; %choiceof1/4,1/8,1/16,and1/32
delta=G*Tu; %guardbandduration
Ts=delta+Tu; %totalOFDMsymbolperiod
Kmax=1705; %numberofsubcarriers
Kmin=0;
FS=4096; %IFFT/FFTlength
q=10; %carrierperiodtoelementaryperiodratio
fc=q*1/T; %carrierfrequency
Rs=4*fc; %simulationperiod
t=0:1/Rs:Tu;
%Datagenerator(A)
M=Kmax+1;
rand('state',0);
a=-1+2*round(rand(M,1)).'+i*(-1+2*round(rand(M,1))).';
A=length(a);
info=zeros(FS,1);
info(1A/2))=[a(1A/2)).']; %Zeropadding
info((FS-((A/2)-1)):FS)=[a(((A/2)+1):A).'];
%Subcarriersgeneration(B)
carriers=FS.*ifft(info,FS);
tt=0:T/2:Tu;
figure(1);
subplot(211);
stem(tt(1:20),real(carriers(1:20)));

subplot(212);
stem(tt(1:20),imag(carriers(1:20)));
figure(2);
f=(2/T)*(1FS))/(FS);
subplot(211);
plot(f,abs(fft(carriers,FS))/FS);
subplot(212);
pwelch(carriers,[],[],[],2/T);
%D/Asimulation
L=length(carriers);
chips=[carriers.';zeros((2*q)-1,L)];
p=1/Rs:1/Rs:T/2;
g=ones(length(p),1); %pulseshape
figure(3);
stem(p,g);
dummy=conv(g,chips));
u=[dummy(1:length(t))]; %(C)
figure(4);
subplot(211);
plot(t(1:400),real(u(1:400)));
subplot(212);
plot(t(1:400),imag(u(1:400)));
figure(5);
ff=(Rs)*(1q*FS))/(q*FS);
subplot(211);
plot(ff,abs(fft(u,q*FS))/FS);
subplot(212);
pwelch(u,[],[],[],Rs);
[b,a]=butter(13,1/20); %reconstructionfilter
[H,F]=FREQZ(b,a,FS,Rs);
figure(6);
plot(F,20*log10(abs(H)));
uoft=filter(b,a,u); %basebandsignal(D)
figure(7);
subplot(211);
plot(t(80:480),real(uoft(80:480)));
subplot(212);
plot(t(80:480),imag(uoft(80:480)));
figure(8);
subplot(211);
plot(ff,abs(fft(uoft,q*FS))/FS);
subplot(212);
pwelch(uoft,[],[],[],Rs);
%Upconverter
s_tilde=(uoft.').*exp(1i*2*pi*fc*t);
s=real(s_tilde); %passbandsignal(E)
figure(9);
plot(t(80:480),s(80:480));
figure(10);
subplot(211);
%plot(ff,abs(fft(((real(uoft).').*cos(2*pi*fc*t)),q*FS))/FS);
%plot(ff,abs(fft(((imag(uoft).').*sin(2*pi*fc*t)),q*FS))/FS);
plot(ff,abs(fft(s,q*FS))/FS);
subplot(212);
%pwelch(((real(uoft).').*cos(2*pi*fc*t)),[],[],[],Rs);
%pwelch(((imag(uoft).').*sin(2*pi*fc*t)),[],[],[],Rs);
pwelch(s,[],[],[],Rs);

5.2 OFDM Reception

%DVB-T2KReception
clearall;
closeall;
Tu=224e-6; %usefulOFDMsymbolperiod
T=Tu/2048; %basebandelementaryperiod
G=0; %choiceof1/4,1/8,1/16,and1/32
delta=G*Tu; %guardbandduration
Ts=delta+Tu; %totalOFDMsymbolperiod
Kmax=1705; %numberofsubcarriers
Kmin=0;
FS=4096; %IFFT/FFTlength
q=10; %carrierperiodtoelementaryperiodratio
fc=q*1/T; %carrierfrequency
Rs=4*fc; %simulationperiod
t=0:1/Rs:Tu;
tt=0:T/2:Tu;
%Datagenerator
sM=2;
[x,y]=meshgrid((-sM+1):2sM-1),(-sM+1):2sM-1));
alphabet=x)+1i*y);
N=Kmax+1;
rand('state',0);
a=-1+2*round(rand(N,1)).'+i*(-1+2*round(rand(N,1))).';
A=length(a);
info=zeros(FS,1);
info(1A/2))=[a(1A/2)).'];
info((FS-((A/2)-1)):FS)=[a(((A/2)+1):A).'];
carriers=FS.*ifft(info,FS);
%Upconverter
L=length(carriers);
chips=[carriers.';zeros((2*q)-1,L)];
p=1/Rs:1/Rs:T/2;
g=ones(length(p),1);
dummy=conv(g,chips));
u=[dummy;zeros(46,1)];
[b,aa]=butter(13,1/20);
uoft=filter(b,aa,u);
delay=64; %Reconstructionfilterdelay
s_tilde=(uoft(delay+(1:length(t))).').*exp(1i*2*pi*fc*t);
s=real(s_tilde);
%OFDMRECEPTION
%Downconversion
r_tilde=exp(-1i*2*pi*fc*t).*s; %(F)
figure(1);
subplot(211);
plot(t,real(r_tilde));
axis([0e-712e-7-6060]);
gridon;
figure(1);
subplot(212);
plot(t,imag(r_tilde));
axis([0e-712e-7-100150]);
gridon;
figure(2);
ff=(Rs)*(1q*FS))/(q*FS);
subplot(211);
plot(ff,abs(fft(r_tilde,q*FS))/FS);
gridon;
figure(2);
subplot(212);
pwelch(r_tilde,[],[],[],Rs);
%Carriersuppression
[B,AA]=butter(3,1/2);
r_info=2*filter(B,AA,r_tilde); %Basebandsignalcontinuous-time(G)
figure(3);
subplot(211);
plot(t,real(r_info));
axis([012e-7-6060]);
gridon;
figure(3);
subplot(212);
plot(t,imag(r_info));
axis([012e-7-100150]);
gridon;
figure(4);
f=(2/T)*(1FS))/(FS);
subplot(211);
plot(ff,abs(fft(r_info,q*FS))/FS);
gridon;
subplot(212);
pwelch(r_info,[],[],[],Rs);
%Sampling
r_data=real(r_info(12*q):length(t)))... %Basebandsignal,discrete-
time
+1i*imag(r_info(12*q):length(t))); %(H)
figure(5);
subplot(211);
stem(tt(1:20),(real(r_data(1:20))));
axis([012e-7-6060]);
gridon;
figure(5);
subplot(212);
stem(tt(1:20),(imag(r_data(1:20))));
axis([012e-7-100150]);
gridon;
figure(6);
f=(2/T)*(1FS))/(FS);
subplot(211);
plot(f,abs(fft(r_data,FS))/FS);
gridon;
subplot(212);
pwelch(r_data,[],[],[],2/T);
%FFT
info_2N=(1/FS).*fft(r_data,FS); %(I)
info_h=[info_2N(1:A/2)info_2N((FS-((A/2)-1)):FS)];
%Slicing
for k=1:N,
a_hat(k)=alphabet((info_h(k)-alphabet)==min(info_h(k)-alphabet)
(J)
end;
figure(7)
plot(info_h((1:A)),'.k');
title('info-hReceivedConstellation')
axissquare;
axisequal;
figure(8)
plot(a_hat((1:A)),'or');
title('a_hat4-QAM')
axissquare;
axisequal;
gridon;
axis([-1.51.5-1.51.5]);
Can you help me? this is urgent!!! thnx

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