i want to generate an fft signal in below ofdm signal code ?????

% OFDM Code % Author: Ihsan Ullah, % Ms-55 Electrical, % College of EME, % NUST Pakistan % No.of Carriers: 64 % coding used: Convolutional coding % Single frame size: 96 bits % Total no. of Frames: 100 % Modulation: 16-QAM % No. of Pilots: 4 % Cylic Extension: 25%(16)

close all clear all clc

%% % Generating and coding data t_data=randint(9600,1)'; x=1; si=1; %for BER rows %% for d=1:100; data=t_data(x:x+95); x=x+96; k=3; n=6; s1=size(data,2); % Size of input matrix j=s1/k;

%% % Convolutionally encoding data constlen=7; codegen = [171 133]; % Polynomial trellis = poly2trellis(constlen, codegen); codedata = convenc(data, trellis); %% %Interleaving coded data

s2=size(codedata,2); j=s2/4; matrix=reshape(codedata,j,4);

intlvddata = matintrlv(matrix',2,2)'; % Interleave. intlvddata=intlvddata';

%% % Binary to decimal conversion

dec=bi2de(intlvddata','left-msb');

%% %16-QAM Modulation

M=16; y = qammod(dec,M); % scatterplot(y);

%% % Pilot insertion

lendata=length(y); pilt=3+3j; nofpits=4;

k=1;

for i=(1:13:52)

    pilt_data1(i)=pilt;

    for j=(i+1:i+12);
        pilt_data1(j)=y(k);
        k=k+1;
    end
end
pilt_data1=pilt_data1';   % size of pilt_data =52
pilt_data(1:52)=pilt_data1(1:52);    % upsizing to 64
pilt_data(13:64)=pilt_data1(1:52);   % upsizing to 64

for i=1:52

    pilt_data(i+6)=pilt_data1(i);

end

%% % IFFT

ifft_sig=ifft(pilt_data',64);

%% % Adding Cyclic Extension

cext_data=zeros(80,1); cext_data(1:16)=ifft_sig(49:64); for i=1:64

    cext_data(i+16)=ifft_sig(i);

end

%% % Channel

 % SNR

 o=1;
for snr=0:2:50

ofdm_sig=awgn(cext_data,snr,'measured'); % Adding white Gaussian Noise % figure; % index=1:80; % plot(index,cext_data,'b',index,ofdm_sig,'r'); %plot both signals % legend('Original Signal to be Transmitted','Signal with AWGN'); %% % RECEIVER %% %Removing Cyclic Extension

for i=1:64

    rxed_sig(i)=ofdm_sig(i+16);

end

%% % FFT

ff_sig=fft(rxed_sig,64);

%% % Pilot Synch%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

for i=1:52

    synched_sig1(i)=ff_sig(i+6);

end

k=1;

for i=(1:13:52)

    for j=(i+1:i+12);
        synched_sig(k)=synched_sig1(j);
        k=k+1;
    end
end

% scatterplot(synched_sig)

%% % Demodulation dem_data= qamdemod(synched_sig,16); %% % Decimal to binary conversion

bin=de2bi(dem_data','left-msb'); bin=bin';

%% % De-Interleaving

deintlvddata = matdeintrlv(bin,2,2); % De-Interleave deintlvddata=deintlvddata'; deintlvddata=deintlvddata(:)';

%% %Decoding data n=6; k=3; decodedata =vitdec(deintlvddata,trellis,5,'trunc','hard'); % decoding datausing veterbi decoder rxed_data=decodedata;

%% % Calculating BER rxed_data=rxed_data(:)'; errors=0;

c=xor(data,rxed_data); errors=nnz(c);

% for i=1:length(data) % % % if rxed_data(i)~=data(i); % errors=errors+1; % % end % end BER(si,o)=errors/length(data); o=o+1;

 end % SNR loop ends here
 si=si+1;
end % main data loop

%% % Time averaging for optimum results

for col=1:25; %%%change if SNR loop Changed ber(1,col)=0; for row=1:100;

        ber(1,col)=ber(1,col)+BER(row,col);
    end
end
ber=ber./100;

%% figure i=0:2:48; semilogy(i,ber); title('BER vs SNR'); ylabel('BER'); xlabel('SNR (dB)'); grid on

[Rick Rosson]

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