www.pudn.com > MultiuserOFDM_0_1.zip > chtry.m

% Copyright (c) 2003-2004 The University of Texas 
% All Rights Reserved. 
%   
% This program is free software; you can redistribute it and/or modify 
% it under the terms of the GNU General Public License as published by 
% the Free Software Foundation; either version 2 of the License, or 
% (at your option) any later version. 
%   
% This program is distributed in the hope that it will be useful, 
% but WITHOUT ANY WARRANTY; without even the implied warranty of 
% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the 
% GNU General Public License for more details. 
%   
% The GNU Public License is available in the file LICENSE, or you 
% can write to the Free Software Foundation, Inc., 59 Temple Place - 
% Suite 330, Boston, MA 02111-1307, USA, or you can find it on the 
% World Wide Web at http://www.fsf.org. 
%   
% Programmers:	Zukang Shen 
%  
% The authors are with the Department of Electrical and Computer 
% Engineering, The University of Texas at Austin, Austin, TX. 
% They can be reached at shen@ece.utexas.edu. 
 
 
 
function [env,I,Q]= chtry(userNum,sampleNum,fm) 
 
 
 
Ts=1e-3; 
N=200; %number of input waves 
n=[0:N-1]; 
cita=2*pi*n/N; %input angles 
 
for user=1:userNum 
alfa1=randn(1,N); %magnitudes of input waves, tap 1 
alfanormed(1,:)=alfa1/sqrt(sum(alfa1.^2)); %normalized magnitude, tap 1 
alfa2=randn(1,N); %magnitudes of input waves, tap 2 
alfanormed(2,:)=alfa2/sqrt(sum(alfa2.^2)); %normalized magnitude, tap 2 
alfa3=randn(1,N); %magnitudes of input waves, tap 3 
alfanormed(3,:)=alfa3/sqrt(sum(alfa3.^2)); %normalized magnitude, tap 3 
alfa4=randn(1,N); %magnitudes of input waves, tap 4 
alfanormed(4,:)=alfa4/sqrt(sum(alfa4.^2)); %normalized magnitude, tap 4 
alfa5=randn(1,N); %magnitudes of input waves, tap 5 
alfanormed(5,:)=alfa5/sqrt(sum(alfa5.^2)); %normalized magnitude, tap 5 
alfa6=randn(1,N); %magnitudes of input waves, tap 6 
alfanormed(6,:)=alfa6/sqrt(sum(alfa6.^2)); %normalized magnitude, tap 6 
 
phaseinit1=randn(1,N); 
phaseinit(1,:)=phaseinit1*2*pi/max(phaseinit1); %initial phases, tap 1 
phaseinit2=randn(1,N); 
phaseinit(2,:)=phaseinit2*2*pi/max(phaseinit2); %initial phases, tap 2 
phaseinit3=randn(1,N); 
phaseinit(3,:)=phaseinit3*2*pi/max(phaseinit3); %initial phases, tap 3 
phaseinit4=randn(1,N); 
phaseinit(4,:)=phaseinit4*2*pi/max(phaseinit4); %initial phases, tap 4 
phaseinit5=randn(1,N); 
phaseinit(5,:)=phaseinit5*2*pi/max(phaseinit5); %initial phases, tap 5 
phaseinit6=randn(1,N); 
phaseinit(6,:)=phaseinit6*2*pi/max(phaseinit6); %initial phases, tap 6 
 
%using one-sided exponential profile 
to=1*Ts; 
tt=[0:5]*Ts; 
g=exp(-tt/to);%relative engery for the 6 taps 
 
    for j=1:6 
        for i=0:sampleNum-1 
            t=i*Ts; 
            is=g(j)*sum(alfanormed(j,:).*cos(2*pi*fm*t*cos(cita)+phaseinit(j,:))); 
            qs=g(j)*sum(alfanormed(j,:).*sin(2*pi*fm*t*cos(cita)+phaseinit(j,:))); 
            I(user,j,i+1)=is; 
            Q(user,j,i+1)=qs; 
            envs=sqrt(qs^2+is^2); 
            env(user,j,i+1)=envs; 
        end 
    end 
 
end 
 
for i=1:sampleNum 
envtmp(i)=env(1,1,i); 
end 
% figure 
% stem([0:sampleNum-1]*Ts, 20*log10(envtmp)) 
% title('Rayleigh Fading') 
% xlabel('t') 
% ylabel('r(t)') 
%  
% figure 
% stem([0:sampleNum-1]*Ts, envtmp) 
% title('Rayleigh Fading') 
% xlabel('t') 
% ylabel('r(t)')