GNU Radio Manual and C++ API Reference 3.7.14.0
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ofdm_equalizer_static.h
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1/* -*- c++ -*- */
2/* Copyright 2012 Free Software Foundation, Inc.
3 *
4 * This file is part of GNU Radio
5 *
6 * GNU Radio is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 3, or (at your option)
9 * any later version.
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11 * GNU Radio is distributed in the hope that it will be useful,
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13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
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17 * along with GNU Radio; see the file COPYING. If not, write to
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20 */
21
22#ifndef INCLUDED_DIGITAL_OFDM_EQUALIZER_STATIC_H
23#define INCLUDED_DIGITAL_OFDM_EQUALIZER_STATIC_H
24
28
29namespace gr {
30namespace digital {
31
32/*!
33 * \brief Very simple static equalizer for OFDM.
34 * \ingroup ofdm_blk
35 * \ingroup equalizers_blk
36 *
37 * \details
38 * This is an extremely simple equalizer. It will only work for
39 * high-SNR, very, very slowly changing channels.
40 *
41 * It simply divides the signal with the currently known channel
42 * state. Whenever a pilot symbol comes around, it updates the
43 * channel state on that particular carrier by dividing the
44 * received symbol with the known pilot symbol.
45 */
47{
48public:
49 typedef boost::shared_ptr<ofdm_equalizer_static> sptr;
50
52 const std::vector<std::vector<int> >& occupied_carriers =
53 std::vector<std::vector<int> >(),
54 const std::vector<std::vector<int> >& pilot_carriers =
55 std::vector<std::vector<int> >(),
56 const std::vector<std::vector<gr_complex> >& pilot_symbols =
57 std::vector<std::vector<gr_complex> >(),
58 int symbols_skipped = 0,
59 bool input_is_shifted = true);
61
62 /*! \brief Divide the input signal with the current channel state.
63 *
64 * Does the following (and nothing else):
65 * - Divide every OFDM symbol with the current channel state
66 * - If a pilot symbol is found, re-set the channel state by dividing the received
67 * symbol with the known pilot symbol
68 */
69 void equalize(gr_complex* frame,
70 int n_sym,
71 const std::vector<gr_complex>& initial_taps = std::vector<gr_complex>(),
72 const std::vector<tag_t>& tags = std::vector<tag_t>());
73
74 /*
75 * \param fft_len FFT length
76 * \param occupied_carriers List of occupied carriers, see ofdm_carrier_allocator
77 * for a description.
78 * \param pilot_carriers Position of pilot symbols, see ofdm_carrier_allocator
79 * for a description.
80 * \param pilot_symbols Value of pilot symbols, see ofdm_carrier_allocator
81 * for a description.
82 * \param symbols_skipped Starting position within occupied_carriers and
83 * pilot_carriers. If the first symbol of the frame was removed (e.g. to decode the
84 * header), set this make sure the pilot symbols are correctly
85 * identified.
86 * \param input_is_shifted Set this to false if the input signal is not shifted, i.e.
87 * the first input items is on the DC carrier.
88 * Note that a lot of the OFDM receiver blocks operate on
89 * shifted signals!
90 */
91 static sptr make(int fft_len,
92 const std::vector<std::vector<int> >& occupied_carriers =
93 std::vector<std::vector<int> >(),
94 const std::vector<std::vector<int> >& pilot_carriers =
95 std::vector<std::vector<int> >(),
96 const std::vector<std::vector<gr_complex> >& pilot_symbols =
97 std::vector<std::vector<gr_complex> >(),
98 int symbols_skipped = 0,
99 bool input_is_shifted = true);
100};
101
102} /* namespace digital */
103} /* namespace gr */
104
105#endif /* INCLUDED_DIGITAL_OFDM_EQUALIZER_STATIC_H */
Definition: ofdm_equalizer_base.h:70
boost::shared_ptr< ofdm_equalizer_base > sptr
Definition: ofdm_equalizer_base.h:45
Very simple static equalizer for OFDM.
Definition: ofdm_equalizer_static.h:47
void equalize(gr_complex *frame, int n_sym, const std::vector< gr_complex > &initial_taps=std::vector< gr_complex >(), const std::vector< tag_t > &tags=std::vector< tag_t >())
Divide the input signal with the current channel state.
ofdm_equalizer_static(int fft_len, const std::vector< std::vector< int > > &occupied_carriers=std::vector< std::vector< int > >(), const std::vector< std::vector< int > > &pilot_carriers=std::vector< std::vector< int > >(), const std::vector< std::vector< gr_complex > > &pilot_symbols=std::vector< std::vector< gr_complex > >(), int symbols_skipped=0, bool input_is_shifted=true)
static sptr make(int fft_len, const std::vector< std::vector< int > > &occupied_carriers=std::vector< std::vector< int > >(), const std::vector< std::vector< int > > &pilot_carriers=std::vector< std::vector< int > >(), const std::vector< std::vector< gr_complex > > &pilot_symbols=std::vector< std::vector< gr_complex > >(), int symbols_skipped=0, bool input_is_shifted=true)
boost::shared_ptr< ofdm_equalizer_static > sptr
Definition: ofdm_equalizer_static.h:49
#define DIGITAL_API
Definition: gr-digital/include/gnuradio/digital/api.h:30
std::complex< float > gr_complex
Definition: gr_complex.h:27
Include this header to use the message passing features.
Definition: basic_block.h:45