create_channel.m

code for signal Processing in OFDM calculation.

function [H, H_f]=create_channel(Mt, Mr, A, N);
% function [H, H_f]=create_channel(Mt, Mr, A, N);
%
%   A - vector containing the power-delay profile (real values)
%   Mt - number of Tx antennas
%   Mr - number of Rx antennas
%   N - number of vector symbols to be sent in a single OFDM symbol Tx
%       ie: N MIMO transmissions in one OFDM symbol

% This is for Rayleigh frequency-selective fading, which assumes complex
% Gaussian matrix elements with in-phase and quadrature components independent.
% Assume iid matrix channel elements, and further, independent channel taps

% define the channel taps
H_int = 1/sqrt(2)*(randn(Mr*length(A),Mt) + j*randn(Mr*length(A),Mt));

H_int2=[];
for i = 1:length(A)
    H_int2 = [H_int2;sqrt(A(i))*H_int((i-1)*Mr+1:i*Mr,:)];
end

%h_f = fft(H_int2',64);

%%H = H_int2';

H_int2 = [H_int2;zeros((N-length(A))*Mr,Mt)];

H_f = zeros(Mr,Mt*(N-16));
for i = 1:Mt
    for j = 1:Mr
        h_f = fft(H_int2(j:Mr:(N-16-1)*Mr+j,i));
        for k = 1:(N-16)
            H_f(j,i+(k-1)*Mt) = h_f(k);
        end
    end
end

H=[H_int2];
for i = 1:N-1
    H=[H,[zeros(Mr*i,Mt);H_int2(1:(N-i)*Mr,:)]];
end