transmitter.m

Mat lab code of OFDM using BPSK

function [t_data r_ifft c_ifft]=transmitter(M,nc,bits)

len_cp = ceil(0.1*nc);  %   length of cyclic prefix
ifft_points = nc;           
fft_points = nc;
empt=[]; ex1=[];rx=[];
data = randsrc(1, bits, 0:M-1);
figure(1)
stem(data); grid on; 
title('Transmitted Data ')

modulated_data = pskmod(data, M,pi/4);

    for i=1:length(modulated_data);   
     for j=1:nc; 
   ex1=[ex1 modulated_data(:,i)];
   end
    end

figure(1)
scatterplot(ex1);

title('QPSK Modulation')

num_cols=length(ex1)/nc;

data_matrix = reshape(ex1, nc, num_cols);

cp_start = nc-len_cp;
cp_end = nc;


for i=1:num_cols
    ifft_data_matrix(:,i) = ifft((data_matrix(:,i)),ifft_points);
    
    for j=1:len_cp,
       actual_cp(j,i) = ifft_data_matrix(j+cp_start,i);
    end
       ifft_data(:,i) = vertcat(actual_cp(:,i),ifft_data_matrix(:,i));
end

[rows_ifft_data cols_ifft_data]=size(ifft_data);

ofdm_data = rows_ifft_data*cols_ifft_data;

ofdm_signal = reshape(ifft_data, 1, ofdm_data);

figure(3)

plot(real(ofdm_signal)); 
title('Real part of OFDM Signal');
grid on;
figure(4)
plot(imag(ofdm_signal)); 
title('Imaginary part of OFDM Signal');
grid on;
 t_data=ofdm_signal;
 r_ifft=rows_ifft_data;
 c_ifft=cols_ifft_data ;