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puncture_bb.h
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/* -*- c++ -*- */
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/*
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* Copyright 2014 Free Software Foundation, Inc.
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*
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* This file is part of GNU Radio
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*
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* GNU Radio is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 3, or (at your option)
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* any later version.
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*
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* GNU Radio is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with GNU Radio; see the file COPYING. If not, write to
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* the Free Software Foundation, Inc., 51 Franklin Street,
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* Boston, MA 02110-1301, USA.
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*/
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#ifndef INCLUDED_FEC_PUNCTURE_BB_H
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#define INCLUDED_FEC_PUNCTURE_BB_H
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#include <
gnuradio/fec/api.h
>
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#include <
gnuradio/block.h
>
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namespace
gr {
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namespace
fec {
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/*!
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* \brief Puncture a stream of unpacked bits.
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* \ingroup error_coding_blk
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*
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* \details
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* Puncture a given block of input samples of \p puncsize. The
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* items produced is based on pattern \p puncpat. Basically, if:
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*
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* \code
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* k = 0
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* if _puncpat[i] == 1:
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* out[k++] = input[i]
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* \endcode
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*
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* This block is designed for unpacked bits - that is, every
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* input sample is a bit, either a 1 or 0. It's possible to use
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* packed bits as symbols, but the puncturing will be done on
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* the symbol level, not the bit level.
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*
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* \p puncpat is specified as a 32-bit integer that we can
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* convert into the vector _puncpat used in the algorithm above:
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*
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* \code
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* _puncpat = [0,...]
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* for i in puncsize:
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* _puncpat[i] = puncpat >> (puncsize-1-i)
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* \endcode
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*
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* Example:
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* \code
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* puncsize = 8
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* puncpat = 0xEF --> [1,1,1,0,1,1,1,1]
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* input = [a, b, c, d, e, f, g, h]
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* output = [a, b, c, e, f, g, h]
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* \endcode
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*
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* The gr.fec Python module provides a read_bitlist function
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* that can turn a string of a puncture pattern into the correct
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* integer form. The pattern of 0xEF could be specified as
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* fec.readbitlist("11101111"). Also, this allows us to use
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* puncsize=len("11101111") to make sure that our sizes are set
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* up correctly for the pattern we want.
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*
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* The fec.extended_encoder takes in the puncture pattern
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* directly as a string and uses the readbitlist inside to do
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* the conversion.
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*
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* The \p delay parameter delays the application of the puncture
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* pattern. This is equivalent to circularly rotating the \p
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* puncpat by \p delay. Note that because of the circular shift,
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* the delay should be between 0 and \p puncsize, but this is
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* not enforced; the effective delay will simply be \p delay mod
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* \p puncsize. A negative value here is ignored.
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*/
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class
FEC_API
puncture_bb
:
virtual
public
block
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{
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public
:
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// gr::fec::puncture_bb::sptr
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typedef
boost::shared_ptr<puncture_bb>
sptr
;
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/*!
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* \brief Constructs a puncture block for unpacked bits.
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*
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* \param puncsize Size of block of bits to puncture
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* \param puncpat The puncturing pattern
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* \param delay Delayed the puncturing pattern by shifting it
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*/
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static
sptr
make(
int
puncsize,
int
puncpat,
int
delay=0);
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};
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}
/* namespace fec */
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}
/* namespace gr */
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#endif
/* INCLUDED_FEC_PUNCTURE_BB_H */
gr-fec
include
gnuradio
fec
puncture_bb.h
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