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/* -*- c++ -*- */
/*
* Copyright 2013 Free Software Foundation, Inc.
*
* This file is part of GNU Radio
*
* SPDX-License-Identifier: GPL-3.0-or-later
*
*/
#ifndef INCLUDED_DIGITAL_OFDM_CHANEST_VCVC_IMPL_H
#define INCLUDED_DIGITAL_OFDM_CHANEST_VCVC_IMPL_H
#include <gnuradio/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() override;
void forecast(int noutput_items, gr_vector_int& ninput_items_required) override;
int general_work(int noutput_items,
gr_vector_int& ninput_items,
gr_vector_const_void_star& input_items,
gr_vector_void_star& output_items) override;
};
} // namespace digital
} // namespace gr
#endif /* INCLUDED_DIGITAL_OFDM_CHANEST_VCVC_IMPL_H */
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