disptrell.m

MIMO and VBLAST( please see the documentation)

function disptrell(lt_data,lt_state,data_est,state_est,varargin)

%DISPTRELL Display decoding process in graphical form.
%   DISPTRELL(LT_DATA,LT_STATE,DATA_EST,STATE_EST) displays most
%   probable path and data estimations in decoding process.  
%   LT_DATA and LT_STATE 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 DETECT function
%   to speed up decoding process.
%
%   DISPTRELL(LT_DATA,LT_STATE,DATA_EST,STATE_EST,SHRINK) allows to
%   set a SHRINK factor; 0 < SHRINK < 0.5. Default value for SHRINK
%   is 0.5. This corresponds to 100 % of figure height.
%
%   See also DETECT.

%   Copyright 2001-2002 Kamil Anis, [e-mail]
%   Dept. of Radioelectronics, 
%   Faculty of Electrical Engineering
%   Czech Technical University in Pragu
%   $Revision: 2.0 $  $Date: 2002/10/23 17:33:28 $
%   --
%   <additional stuff should go here>

[s,md,space_dim] = size(lt_data);
[symbols,foo,frames] = size(data_est);
framecut = 15;

% only one frame perfigure can be displayed
if frames > 1
	[indent,gap,name] =  iprompt('DISPTRELL:');

  str5 = num2str(frames);

  disp(' ');
  disp([name,gap,'Data consists from ',str5,' frame(s).']);
  disp([indent,'Only one frame per figure can be displayed!'])
  disp(' ');

  data_est = data_est(:,1,1);
end

% max 20 symbols can be displayed
if symbols > 20
	[indent,gap,name] =  iprompt('DISPTRELL:');

  str6 = num2str(framecut);

  disp(' ');
  disp([name,gap,'Frame is too long!']);
  disp([indent,'Only first ',str6,' symbols will be displayed.'])
  disp(' ');

	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;
clf;

for k = 1:endstate
	x1 = k; x2 = k + 1;
	for i = 1:s
		for j = 1:md
			y1 = i;
			y2 = lt_state(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,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]')
text(0.5,-0.5,'States','HorizontalAlignment','Center')
legend([backpath;trellis],['Back path  ';'Transitions']);

figtitle = ['Best path found with Viterbi iterative decoder'];
wintitle = ['DISPTRELLIS: ',figtitle];
ft = title(figtitle);

set(ft,'FontWeight','bold','FontSize',12);
set(gcf,'Name',wintitle);

axis([1,endstate + 1,1 - (s / shrink_axis),s + (s / shrink_axis)]);
axis off;
view(0,-90);