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function codeword = TurboEncode( data, code_interleaver, pun_pattern, tail_pattern, g1, nsc_flag1, g2, nsc_flag2 )
% TurboEncode encodes a data sequence using a binary turbo encoder.
% If the data length is an integer multiple of the interleaver length, then
% multiple codewords are returned, (one per row of the codeword matrix).
%
% The calling syntax is:
% codeword = TurboEncode( data, code_interleaver, pun_pattern, tail_pattern, g1, nsc_flag1, g2, nsc_flag2 )
%
% codeword = the codeword generated by the encoder,
% will contain multiple rows if the data is longer than the
% interleaver
%
% data = the row vector of data bits
% code_interleaver = the turbo interleaver
% pun_pattern = the puncturing pattern for all but the tail
% tail_pattern = the puncturing pattern just for the tail
% g1 = the first generator polynomial
% nsc_flag1 = 0 if first encoder is RSC and 1 if NSC
% g2 = the second generator polynomial
% nsc_flag2 = 0 if second encoder is RSC and 1 if NSC
%
% Copyright (C) 2005, Matthew C. Valenti
%
% Last updated on Dec. 13, 2005
%
% Function TurboEncode is part of the Iterative Solutions Coded Modulation
% Library (ISCML).
%
% The Iterative Solutions Coded Modulation Library is free software;
% you can redistribute it and/or modify it under the terms of
% the GNU Lesser General Public License as published by the
% Free Software Foundation; either version 2.1 of the License,
% or (at your option) any later version.
%
% This library is distributed in the hope that it will be useful,
% but WITHOUT ANY WARRANTY; without even the implied warranty of
% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
% Lesser General Public License for more details.
%
% You should have received a copy of the GNU Lesser General Public
% License along with this library; if not, write to the Free Software
% Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
% determine the size of the two generators
[N1,K1] = size( g1 );
[N2,K2] = size( g2 );
% in the future, we will allow constituent codes with different constraint lengths
if ( K1 ~= K2 )
error( 'The constraint lengths of the two PCCC constituent codes must be indentical' );
end
% check interleaver length against data length
K_data = length( data );
K_interleaver = length( code_interleaver );
if ( rem( K_data, K_interleaver ) )
error( 'The data length needs to be an integer multiple of the interleaver length' );
end
number_codewords = K_data/K_interleaver;
data = reshape( data, K_interleaver, number_codewords)';
for codeword_index=1:number_codewords
% Encode in parallel (fixed on 2-1-06)
upper_output = ConvEncode( data(codeword_index,:), g1, nsc_flag1 );
lower_output = ConvEncode( Interleave( data(codeword_index,:), code_interleaver), g2, nsc_flag2 );
% convert to matrices (each row is from one row of the generator)
upper_reshaped = [ reshape( upper_output, N1, length(upper_output)/N1 ) ];
lower_reshaped = [ reshape( lower_output, N2, length(lower_output)/N2 ) ];
% parallel concatenate
unpunctured_word = [upper_reshaped
lower_reshaped];
codeword(codeword_index,:) = Puncture( unpunctured_word, pun_pattern, tail_pattern );
end
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