ofdm_equalizer_base.h

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/* -*- c++ -*- */
/* Copyright 2012 Free Software Foundation, Inc.
 *
 * This file is part of GNU Radio
 *
 * SPDX-License-Identifier: GPL-3.0-or-later
 *
 */
 
#ifndef INCLUDED_DIGITAL_OFDM_EQUALIZER_BASE_H
#define INCLUDED_DIGITAL_OFDM_EQUALIZER_BASE_H
 
#include <gnuradio/digital/api.h>
#include <gnuradio/gr_complex.h>
#include <gnuradio/tags.h>
 
namespace gr {
namespace digital {
 
/*!
 * \brief Base class for implementation details of frequency-domain OFDM equalizers.
 * \ingroup ofdm_blk
 * \ingroup equalizers_blk
 */
class DIGITAL_API ofdm_equalizer_base
    : public std::enable_shared_from_this<ofdm_equalizer_base>
{
protected:
    int d_fft_len;
 
public:
    typedef std::shared_ptr<ofdm_equalizer_base> sptr;
 
    ofdm_equalizer_base(int fft_len);
    virtual ~ofdm_equalizer_base();
 
    //! Reset the channel information state knowledge
    virtual void reset() = 0;
    //! Run the actual equalization
    virtual 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>()) = 0;
    //! Return the current channel state
    virtual void get_channel_state(std::vector<gr_complex>& taps) = 0;
    int fft_len() { return d_fft_len; };
    sptr base() { return shared_from_this(); };
};
 
 
/* \brief Base class for implementation details of 1-dimensional OFDM FDEs which use pilot
 * tones. \ingroup digital
 *
 */
class DIGITAL_API ofdm_equalizer_1d_pilots : public ofdm_equalizer_base
{
protected:
    //! If \p d_occupied_carriers[k][l] is true, symbol k, carrier l is carrying data.
    //  (this is a different format than occupied_carriers!)
    std::vector<bool> d_occupied_carriers;
    //! If \p d_pilot_carriers[k][l] is true, symbol k, carrier l is carrying data.
    //  (this is a different format than pilot_carriers!)
    std::vector<std::vector<bool>> d_pilot_carriers;
    //! If \p d_pilot_carriers[k][l] is true, d_pilot_symbols[k][l] is its tx'd value.
    //  (this is a different format than pilot_symbols!)
    std::vector<std::vector<gr_complex>> d_pilot_symbols;
    //! In case the frame doesn't begin with OFDM symbol 0, this is the index of the first
    //! symbol
    int d_symbols_skipped;
    //! The current position in the set of pilot symbols
    int d_pilot_carr_set;
    //! Vector of length d_fft_len saving the current channel state (on the occupied
    //! carriers)
    std::vector<gr_complex> d_channel_state;
 
public:
    typedef std::shared_ptr<ofdm_equalizer_1d_pilots> sptr;
 
    ofdm_equalizer_1d_pilots(int fft_len,
                             const std::vector<std::vector<int>>& occupied_carriers,
                             const std::vector<std::vector<int>>& pilot_carriers,
                             const std::vector<std::vector<gr_complex>>& pilot_symbols,
                             int symbols_skipped,
                             bool input_is_shifted);
    ~ofdm_equalizer_1d_pilots() override;
 
    void reset() override;
    void get_channel_state(std::vector<gr_complex>& taps) override;
};
 
} /* namespace digital */
} /* namespace gr */
 
#endif /* INCLUDED_DIGITAL_OFDM_EQUALIZER_BASE_H */