ifft_tx_mc.m

mc-cdma matlab下的性能仿真

% *****************************************************
% ifft_tx_multiuser.m
%
% Function to perform multiuser IFFT
%
% Programmed by SP.Feng
%******************************************************

function ofdm_symbol = ifft_tx_multiuserOpt(inputData,num_user,num_data,num_subc,guard_interval)

%------------------------------------------------------------
% IFFT and Circular Prefix Addition Block for Transmitter
% -------------------------------------------------------
% 
% Inputs : 
%   inpuptData     : Input Symbol from all the Subcarriers
%   num_subc       : Number of Subcarriers
%   num_user       : Number of Users
%   guard_interval : Guard Interval based on OFDM Symbol  
% Outputs : 
%   ofdm symbol    : Output of IFFT and Guard Interval
% -----------------------------------------------------------


inp_symbol = reshape(inputData.',8,num_data/8);

% ofdm_symbol_multiuser = zeros(num_data/8,num_subc + guard_interval,num_user);

pad_zero = [];
for p=2:num_user
    
    pad_zero = [pad_zero zeros(num_data/8,8)];
end

inp_symbol1 = inp_symbol.';
inp_symbol2 = [pad_zero inp_symbol1];
    
    
ofdm_symbol = [];
for i=1:(num_data/8)
    ofdm_symbol = [ofdm_symbol;ifft(inp_symbol2(i,:),num_subc)];

    if (guard_interval > length(ofdm_symbol))
        error(' The guard interval is greater than the ofdm symbol duration ');
    end

% The guard symbol is the copy of the end of the ofdm symbol to the beginning
% of the ofdm symbol.
    guard_symbol(i,:) = ofdm_symbol(i,end-guard_interval+1:end);

% Add the cyclic prefix to the ofdm symbol

 end
    ofdm_symbol = [guard_symbol ofdm_symbol];
%     ofdm_symbol_multiuser(:,:,p) = ofdm_symbol;
   
    
% end