diff options
Diffstat (limited to 'gr-digital/lib/digital_ofdm_equalizer_simpledfe.cc')
| -rw-r--r-- | gr-digital/lib/digital_ofdm_equalizer_simpledfe.cc | 101 |
1 files changed, 101 insertions, 0 deletions
diff --git a/gr-digital/lib/digital_ofdm_equalizer_simpledfe.cc b/gr-digital/lib/digital_ofdm_equalizer_simpledfe.cc new file mode 100644 index 0000000000..9abab8c1dd --- /dev/null +++ b/gr-digital/lib/digital_ofdm_equalizer_simpledfe.cc @@ -0,0 +1,101 @@ +/* -*- 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" + +digital_ofdm_equalizer_simpledfe_sptr +digital_make_ofdm_equalizer_simpledfe( + int fft_len, + const 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 digital_ofdm_equalizer_simpledfe_sptr(new digital_ofdm_equalizer_simpledfe( + fft_len, + constellation, + occupied_carriers, + pilot_carriers, + pilot_symbols, + symbols_skipped, + alpha, + input_is_shifted)); +} + +digital_ofdm_equalizer_simpledfe::digital_ofdm_equalizer_simpledfe( + int fft_len, + const 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) + : digital_ofdm_equalizer_1d_pilots(fft_len, occupied_carriers, pilot_carriers, pilot_symbols, symbols_skipped, input_is_shifted), + d_constellation(constellation), + d_alpha(alpha) +{ +} + + +digital_ofdm_equalizer_simpledfe::~digital_ofdm_equalizer_simpledfe() +{ +} + + +void +digital_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(); + } +} + |