www.pudn.com > space-timecodingBrankaVuceticJinhongYuan.rar > disptrell.m, change:2004-03-25,size:2931b

function [flag]=disptrell(dlt,slt,data_est,state_est,varargin) 
 
%************************************************************************** 
%DISPTRELL Display decoding process in graphical form. 
%   DISPTRELL(DLT,SLT,D_E,S_E) displays most probable path and data 
%   estimations in decoding process. DLT and SLT look-up tables are 
%   required to display code trellis with all possible transitions. The 
%   DISPTRELL function doesn't affect the detection process. It's just a 
%   tool intended for lectures and presentations. As it belongs to the 
%   Visual Layer it's not included in the VITERBI function to speed up 
%   decoding process. 
%************************************************************************** 
 
flag=0; 
 
[s,md,space_dim] = size(dlt); 
[symbols,foo,frames] = size(data_est); 
framecut = 15; 
 
% only one frame perfigure can be displayed 
if frames > 1 
  data_est = data_est(:,1,1); 
end 
 
% max 20 symbols can be displayed 
if symbols > 20 
    flag=1; 
  endstate = framecut; 
  data_est = data_est(1:framecut,1,1); 
else 
  endstate = symbols; 
end 
 
% default shrink factor 
if length(varargin) == 1 
  shrink = varargin{1}; 
else 
  shrink = 1 / 2; 
  shrink_axis = (s + 1) * shrink; 
end 
 
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% BODY BEGIN %%%%%%%%%%%%%%%%%%%%%%%%%%%% 
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 
 
offset = 0.1; 
figure; 
clf; 
 
for k = 1:endstate 
  x1 = k; x2 = k + 1; 
  for i = 1:s 
    for j = 1:md 
      y1 = i; 
      y2 = slt(i,j,:); 
      trellis = line([x1 x2],[y1,y2]); 
      set(trellis,'LineStyle',':'); 
    end 
    str = num2str(i); 
    text(0.5,i,str,'HorizontalAlignment','Center'); 
  end 
  backpath = line([k k + 1],[state_est(k) state_est(k + 1)]); 
  set(backpath,'Color','red','LineWidth',2); 
  str1 = num2str(k); 
  text(k + 1,s + 1,str1,'HorizontalAlignment','Center'); 
   
  str2 = num2str(data_est(k)); 
  str3 = text(k + offset,state_est(k) - offset,str2); 
  set(str3,'HorizontalAlignment','Center','FontWeight','bold'); 
end 
 
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% BODY END %%%%%%%%%%%%%%%%%%%%%%%%%%%%% 
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 
 
text((endstate + 1) / 2,s + 2,'Steps [\itk\rm]') 
h=text(4,-0.5,'States: Only one packet displayed','HorizontalAlignment','Center'); 
set(h,'FontWeight','bold','FontSize',12,'Color','b'); 
 
legend([backpath;trellis],['Back path  ';'Transitions']); 
 
figtitle = ['Best path found with Viterbi iterative decoder']; 
wintitle = [figtitle]; 
ft = title(figtitle); 
 
set(ft,'FontWeight','bold','FontSize',12,'Color','r'); 
set(gcf,'Name',wintitle); 
set(gcf,'NumberTitle','off'); 
 
 
axis([1,endstate + 1,1 - (s / shrink_axis),s + (s / shrink_axis)]); 
axis off; 
view(0,-90);