mobmove.m

This is a Matlab script used to extract simulation data from , for the CDMA seminars and homework

function [xym,xyv] = mobmove(xym,xyv,amean,vmean,dt,rhombvec)
% DESCRIPTION
% [xym,xyv] = mobmove(xym,xyv,amean,vmean,dt,rhombvec)
%  Move and initiate position of users.
% INPUT
%  xym --      Complex position of users possibly. NaN for users that have not yet
%              received any position and thus are regarded as new.
%  xyv --      Complex speed [m/s].
%  amean --    Average acceleration of mobiles.
%  vmean --    Mean speed of mobiles. 
%  dt --       Time interval since last call to this routine.
%  rhombvec -- Two complex vectors determining the area within which 
%              mobiles are folded.
% OUTPUT
%  xym --      New position. 
%  xyv --      New speed.
% TRY  
%  plot(mobmove(zeros(1000,1),zeros(1000,1),1,10,1,[1 i]*1000),'.')
%  plot(mobmove(zeros(1000,1),zeros(1000,1),1,10,1,[1 i]*1),'.')
%  plot(mobmove(nans(1000,1),zeros(1000,1),1,10,1,[1+i i]*1000),'.')
% SEE ALSO 
%  

% by Magnus Almgren 000505, dt<=0 MA 010516


% MODIFICATION: 2005.04.17 by Bogdan Timus
mInd = min(11, length(xym));
if isnan(xym(mInd)),
  init = 1;
  vcpy = 200*exp(-1i*pi/6);
else
  init = 0;
  xycpy = xym(mInd);
  vcpy  = xyv(mInd);
end;

% Move users.
if dt>0
 raa = exp(-mdiv(dt.*amean,vmean));
 % raa is the correlation between the new and the old xyv
 % and does not impact the variance.
 xyv = xyv.*raa+sqrt(1-raa.^2).*vmean/sqrt(pi/2).*irandn(size(xyv));
 xym = xym + xyv.*dt;
end
% Give new users speed and position.
newones = isnan(xym);



% Generate position and wrap into simulated area.
xym(newones)= 0;
if exist('rhombvec','var') & sum(abs(rhombvec))>0
 xym(newones) = rand(size(xyv(newones),1),2)*rhombvec(:);
 xym = wrapinto(xym,rhombvec,'hex');
end

% Init speed.
xyv(newones) = vmean/sqrt(pi/2).*irandn(size(xyv(newones))); 

xyv(mInd) = vcpy;
if init,
  xym(mInd) = 2420*exp(-1i*pi/6);
else
  xym(mInd) = xym(mInd) + vcpy*dt;
end;

return

xym = xym(:); % Put into first dimension. Is that necessary?
xyv = xyv(:);

% $Id: mobmove.m,v 1.2 2004/03/11 15:01:31 olav Exp $