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/* -*- c++ -*- */
/* Copyright 2012 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.
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <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)
{
return ofdm_equalizer_simpledfe::sptr(
new ofdm_equalizer_simpledfe(
fft_len,
constellation,
occupied_carriers,
pilot_carriers,
pilot_symbols,
symbols_skipped,
alpha,
input_is_shifted
)
);
}
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)
: ofdm_equalizer_1d_pilots(fft_len, occupied_carriers, pilot_carriers, pilot_symbols, symbols_skipped, input_is_shifted),
d_constellation(constellation),
d_alpha(alpha)
{
}
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<gr_tag_t> &tags)
{
if (!initial_taps.empty()) {
d_channel_state = initial_taps;
}
gr_complex sym_eq, sym_est;
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.size() && d_pilot_carriers[d_pilot_carr_set][k-d_carr_offset]) {
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-d_carr_offset];
frame[i*d_fft_len+k] = d_pilot_symbols[d_pilot_carr_set][k-d_carr_offset];
} else {
sym_eq = frame[i*d_fft_len+k] / d_channel_state[k];
d_constellation->map_to_points(d_constellation->decision_maker(&sym_eq), &sym_est);
d_channel_state[k] = d_alpha * d_channel_state[k] + frame[i*d_fft_len+k] / sym_est;
frame[i*d_fft_len+k] = sym_est;
}
}
d_pilot_carr_set = (d_pilot_carr_set + 1) % d_pilot_carriers.size();
}
}
} /* namespace digital */
} /* namespace gr */
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