function data_enc = space(data,lt_data,lt_state,varargin)%SPACE Space-time channel encoder.%   DATA_ENC = SPACE(DATA,LT_DATA,LT_STATE) performs DATA encoding%   based on LT_DATA and LT_STATE look-up tables. For instance of%   AT&T space-time codes these tables may be easily obtained from%   LTABLE function. In fact the structure of look-up tables is%   as general as possible. By the way the encoder doesn't care about %   content of look-up tables. This feature allow to force the %   encoder operation mode into arbitrary scheme. Even an encoding based%   on block codes may be performed via SPACE function. This is when the%   LT_STATE table contains same entries. There is also a zero-force%   check performed during each frame encoding process. %%   DATA_ENC = SPACE(DATA,LT_DATA,LT_STATE,'FullReport') returns a full%   encoding report in form of table. This feature is available only%   when internal function echo is enabled.%%   DATA_ENC = SPACE(...,'EchoOn') toggles internal function echo on.%%   See also LTABLE, DISPDES.%   Copyright 2001-2002 Kamil Anis, anisk@feld.cvut.cz%   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>[fr_length,l,frames] = size(data);[foo1,md,foo2] = size(lt_data);%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% BODY BEGIN %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%s = 1; % setting up initial statefor k = 1:frames	for i = 1:fr_length                           % stc encoder 		d = data(i,1,k) + 1; % data_dim=1           % stc encoder                          data_enc(i,:,k)=lt_data(s,d,:);             % stc encoder    s=lt_state(s,d,:);                          % stc encoder  end                                           % stc encoder  % zero force flag  if (i == fr_length) & (s ~= 1)     zf_check(k,1) = 0;  else    zf_check(k,1) = 1;  endend%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% BODY END %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%if isempty(varargin) == 0	switch varargin{1}	case 'EchoOn'		[indent,gap,name] = iprompt('SPACE:');			disp(' ');				if zf_check == 1          disp([name,gap,'All frames were encoded successfuly.']);		else          disp([name,gap,'Some frames were encoded uncorrectly!']);          disp([indent,'Use |FullReport| option to get more details.']);		end				if (length(varargin) ==2 ) & (varargin{2} == 'FullReport')			[m,n] = size(zf_check);			table(:,1) = [1:m]';			table(:,2) = zf_check;						disp(' ');			disp([indent,' Frame | Status']);			disp([indent,'-------+-------']);			str1 = sprintf([indent,' #%3d  | %3d\n'],table');			disp(str1);			disp([indent,'Legend: "1" = OK; "0" = wrong encoded.']);		end				disp(' ');	endend