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/* -*- c++ -*- */
/*
* Copyright 2013 Free Software Foundation, Inc.
*
* This file is part of GNU Radio
*
* GNU Radio is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 3, or (at your option)
* any later version.
*
* GNU Radio 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with GNU Radio; see the file COPYING. If not, write to
* the Free Software Foundation, Inc., 51 Franklin Street,
* Boston, MA 02110-1301, USA.
*/
#ifndef INCLUDED_DIGITAL_OFDM_CHANEST_VCVC_IMPL_H
#define INCLUDED_DIGITAL_OFDM_CHANEST_VCVC_IMPL_H
#include <digital/ofdm_chanest_vcvc.h>
namespace gr {
namespace digital {
class ofdm_chanest_vcvc_impl : public ofdm_chanest_vcvc
{
private:
int d_fft_len; //! FFT length
int d_n_data_syms; //! Number of data symbols following the sync symbol(s)
int d_n_sync_syms; //! Number of sync symbols (1 or 2)
//! 0 if no noise reduction is done for the initial channel state estimation. Otherwise, the maximum length of the channel delay in samples.
int d_eq_noise_red_len;
//! Is sync_symbol1 if d_n_sync_syms == 1, otherwise sync_symbol2. Used as a reference symbol to estimate the channel.
std::vector<gr_complex> d_ref_sym;
//! If d_n_sync_syms == 2 this is used as a differential correlation vector (called 'v' in [1]).
std::vector<gr_complex> d_corr_v;
//! If d_n_sync_syms == 1 we use this instead of d_corr_v to estimate the coarse freq. offset
std::vector<float> d_known_symbol_diffs;
//! If d_n_sync_syms == 1 we use this instead of d_corr_v to estimate the coarse freq. offset (temp. variable)
std::vector<float> d_new_symbol_diffs;
//! The index of the first carrier with data (index 0 is not DC here, but the lowest frequency)
int d_first_active_carrier;
//! The index of the last carrier with data
int d_last_active_carrier;
//! If true, the channel estimation must be interpolated
bool d_interpolate;
//! Maximum carrier offset (negative value!)
int d_max_neg_carr_offset;
//! Maximum carrier offset (positive value!)
int d_max_pos_carr_offset;
//! Calculate the coarse frequency offset in number of carriers
int get_carr_offset(const gr_complex *sync_sym1, const gr_complex *sync_sym2);
//! Estimate the channel (phase and amplitude offset per carrier)
void get_chan_taps(const gr_complex *sync_sym1, const gr_complex *sync_sym2, int carr_offset, std::vector<gr_complex> &taps);
public:
ofdm_chanest_vcvc_impl(const std::vector<gr_complex> &sync_symbol1, const std::vector<gr_complex> &sync_symbol2, int n_data_symbols, int eq_noise_red_len, int max_carr_offset, bool force_one_sync_symbol);
~ofdm_chanest_vcvc_impl();
void forecast (int noutput_items, gr_vector_int &ninput_items_required);
int general_work(int noutput_items,
gr_vector_int &ninput_items,
gr_vector_const_void_star &input_items,
gr_vector_void_star &output_items);
};
} // namespace digital
} // namespace gr
#endif /* INCLUDED_DIGITAL_OFDM_CHANEST_VCVC_IMPL_H */
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