ltable.m

MIMO and VBLAST( please see the documentation)

function [lt_data,lt_state] = ltable(md,s,varargin)

%LTABLE Space-time code look-up table generator.
%   [LT_DATA,LT_STATE] = LTABLE(MD,S) creates MD, S-states
%   space-time code data and state look-up tables. MD corresponds
%   to the number of constellation signals e.g. MD-PSK and MD-QAM.
%   The summary of available designs is listed below. 
%
%   [LT_DATA,LT_STATE] = LTABLE(MD,S,METHOD) same as above but 
%   with specific design METHOD. Possible values for METHOD are
%   {'SpaceTime'}|'DelayDiv'|'UsrExtBlock'. When an 'UsrExtBlock'
%   option is chosen an external block code definition is required.
%
%   Type
%
%      type stc_bc16.txt
%
%   to see how the entries in the extern file are stored.
%
%   [LT_DATA,LT_STATE] = LTABLE(...,'EchoOn') toggles internal
%   function echo on.
%
%   TABLE OF AVAILABLE DESIGNS
%
%     #  |  MD | MODULATION | STATES |   METHOD
%   -----+-----+------------+--------+-------------
%     1. |  4  |    PSK     |    4   | 'SpaceTime'
%     2. |  4  |    PSK     |    8   | 'SpaceTime'
%     3. |  4  |    PSK     |   16   | 'SpaceTime'
%     4. |  4  |    PSK     |   32   | 'SpaceTime'
%     5. |  8  |    PSK     |    8   | 'SpaceTime'
%     6. |  8  |    PSK     |    8   | 'DelayDiv'
%     7. |  8  |    PSK     |   16   | 'SpaceTime'
%     8. |  8  |    PSK     |   32   | 'SpaceTime'
%     9. | 16  |    QAM     |   16   | 'SpaceTime'
%    10. | 16  |    QAM     |   16   | 'DelayDiv'
%    11. | 16  |    QAM     |   16   | 'UsrExtBlock'
%
%   See also DISPDES, SPACE.

%   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>



ie = isempty(varargin);

switch ie
case 1
  method = 'SpaceTime'; % default design method
case 0
	switch varargin{1}
	case 'EchoOn'
		method = 'SpaceTime'; % default design method
	otherwise
		method = varargin{1};
	end
end

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% BODY BEGIN %%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

% State matrix generator
base = reshape(1:s,md,s/md)';
lt_state = repmat(base,md,1);

% Data matrix generator
% block code of 16QAM
load stc_bc16.txt;

for j = 1:md
	l = j - 1;
	
	ak = bitget(l,1);
	bk = bitget(l,2);
	dk = bitget(l,3);
	ek = bitget(l,4);
	
	switch md
	% 4 PSK
	case 4
		for i = 1:s
			k = i - 1;
			
			ak_1 = bitget(k,1);
			bk_1 = bitget(k,2);
			ak_2 = bitget(k,3);
			bk_2 = bitget(k,4);
			ak_3 = bitget(k,5);
			bk_3 = bitget(k,6);
			
			switch s
			case 4
				lt_data(i,j,1) = mod(2 * bk_1 + ak_1,md);
				lt_data(i,j,2) = mod(2 * bk + ak,md);
			case 8
				lt_data(i,j,1) = mod(2 * ak_2 + 2 * bk_1 + ak_1,md);
				lt_data(i,j,2) = mod(2 * ak_2 + 2 * bk + ak,md);
			case 16
				lt_data(i,j,1) = mod(2 * ak_2 + 2 * bk_1 + ak_1,md);
				lt_data(i,j,2) = mod(2 * bk_2 + 2 * ak_1 + 2 * bk + ak,md);            
			case 32
				lt_data(i,j,1) = mod(2 * ak_3 + 3 * bk_2 + 2 * ak_2 + 2 * bk_1 +...
					ak_1,md);
				lt_data(i,j,2) = mod(2 * ak_3 + 3 * bk_2 + 2 * bk_1 + ak_1 + 2 *...
          bk + ak,md);
			end
		end
	
	% 8 PSK
	case 8
		for i = 1:s
			k = i - 1;
			
			ak_1 = bitget(k,1);
			bk_1 = bitget(k,2);
			dk_1 = bitget(k,3);
			ak_2 = bitget(k,4);
			bk_2 = bitget(k,5);
			
			switch s
			case 8
        
				switch method
				case 'SpaceTime'
					lt_data(i,j,1) = mod(4 * dk_1 + 2 * bk_1 + 5 * ak_1,md);
					lt_data(i,j,2) = mod(4 * dk + 2 * bk + ak,md);
          
        case 'DelayDiv'
					lt_data(i,j,1)=mod(4 * dk_1 + 2 * bk_1 + ak_1,md);
					lt_data(i,j,2)=mod(4 * dk + 2 * bk + ak,md);
				end
				
			case 16
				lt_data(i,j,1) = mod(ak_2 + 4 * dk_1 + 2 * bk_1 + 5 * ak_1,md);
				lt_data(i,j,2) = mod(5 * ak_2 + 4 * dk_1 + 2 * bk_1 + ak_1 + 4 *...
          dk + 2 * bk + ak,md);
			case 32
				lt_data(i,j,1) = mod(2 * bk_2 + 3 * ak_2 + 4 * dk_1 + 2 * bk_1 +...
          5 *	ak_1,md);
				lt_data(i,j,2) = mod(2 * bk_2 + 7 * ak_2 + 4 * dk_1 + 2 * bk_1 +...
					ak_1 + 4 * dk + 2 * bk + ak,md);
			end
		end
	
	% 16 QAM
	case 16
		for i = 1:s
			k = i - 1;
			
			ak_1 = bitget(k,1);
			bk_1 = bitget(k,2);
			dk_1 = bitget(k,3);
			ek_1 = bitget(k,4);
			
			switch s
			case 16
			
        switch method
				case 'SpaceTime'
					lt_data(i,j,1) = mod(8 * ek_1 + 4 * dk_1 + 2 * bk_1 + 11 *...
            ak_1,md);
					lt_data(i,j,2) = mod(16 * ek_1 + 16 * dk_1 + 16 * bk_1 + 16 *...
						ak_1 + 8 * ek + 4 * dk + 2 * bk + ak,md);
        
        case 'DelayDiv'
					lt_data(i,j,1) = mod(8 * ek_1 + 4 * dk_1 + 2 * bk_1 + ak_1,md);
					lt_data(i,j,2) = mod(8 * ek + 4 * dk + 2 * bk + ak,md);
          
        case 'UsrExtBlock'
					lt_data(i,j,1) = stc_bc16(k + 1,1);
					lt_data(i,j,2) = stc_bc16(k + 1,2) - i + j;
				end
			end
		end
	end
end

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% BODY END %%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

if isempty(varargin) == 0
	switch varargin{end}
	case 'EchoOn'
		[indent,gap,name] =  iprompt('LTABLE:');
		
		str1 = num2str(md);
		str2 = num2str(s);
		
		if (md == 4) | (md == 8)
            str3 = 'PSK';
		else
            str3 = 'QAM';
		end
		
		disp(' ');
		disp([name,gap,'Look-up tables for ',method,' code ',str1,str3,', ',...
        str2,'-states created.']);
		disp(' ');
	end
end