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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
*
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <gnuradio/digital/ofdm_equalizer_simpledfe.h>
namespace gr {
namespace digital {
ofdm_equalizer_simpledfe::sptr
ofdm_equalizer_simpledfe::make(int fft_len,
const gr::digital::constellation_sptr& constellation,
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,
float alpha,
bool input_is_shifted,
bool enable_soft_output)
{
return ofdm_equalizer_simpledfe::sptr(
new ofdm_equalizer_simpledfe(fft_len,
constellation,
occupied_carriers,
pilot_carriers,
pilot_symbols,
symbols_skipped,
alpha,
input_is_shifted,
enable_soft_output));
}
ofdm_equalizer_simpledfe::ofdm_equalizer_simpledfe(
int fft_len,
const gr::digital::constellation_sptr& constellation,
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,
float alpha,
bool input_is_shifted,
bool enable_soft_output)
: ofdm_equalizer_1d_pilots(fft_len,
occupied_carriers,
pilot_carriers,
pilot_symbols,
symbols_skipped,
input_is_shifted),
d_constellation(constellation),
d_alpha(alpha),
d_enable_soft_output(enable_soft_output)
{
}
ofdm_equalizer_simpledfe::~ofdm_equalizer_simpledfe() {}
void ofdm_equalizer_simpledfe::equalize(gr_complex* frame,
int n_sym,
const std::vector<gr_complex>& initial_taps,
const std::vector<tag_t>& tags)
{
if (!initial_taps.empty()) {
d_channel_state = initial_taps;
}
gr_complex sym_eq, sym_est;
bool enable_soft_output = d_enable_soft_output;
for (int i = 0; i < n_sym; i++) {
for (int k = 0; k < d_fft_len; k++) {
if (!d_occupied_carriers[k]) {
continue;
}
if (!d_pilot_carriers.empty() && d_pilot_carriers[d_pilot_carr_set][k]) {
d_channel_state[k] = d_alpha * d_channel_state[k] +
(1 - d_alpha) * frame[i * d_fft_len + k] /
d_pilot_symbols[d_pilot_carr_set][k];
frame[i * d_fft_len + k] = d_pilot_symbols[d_pilot_carr_set][k];
} else {
sym_eq = frame[i * d_fft_len + k] / d_channel_state[k];
// The `map_to_points` function will treat `sym_est` as an array
// pointer. This call is "safe" because `map_to_points` is limited
// by the dimensionality of the constellation. This class calls the
// `constellation` class default constructor, which initializes the
// dimensionality value to `1`. Thus, Only the single `gr_complex`
// value will be dereferenced.
d_constellation->map_to_points(d_constellation->decision_maker(&sym_eq),
&sym_est);
d_channel_state[k] = d_alpha * d_channel_state[k] +
(1 - d_alpha) * frame[i * d_fft_len + k] / sym_est;
frame[i * d_fft_len + k] = enable_soft_output ? sym_eq : sym_est;
}
}
if (!d_pilot_carriers.empty()) {
d_pilot_carr_set = (d_pilot_carr_set + 1) % d_pilot_carriers.size();
}
}
}
} /* namespace digital */
} /* namespace gr */
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