new comments to gsm_receiver_cf.cc
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@ -1,21 +1,21 @@
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/* -*- c++ -*- */
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/*
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* Copyright 2004 Free Software Foundation, Inc.
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* @file
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* @author Piotr Krysik <pkrysik@stud.elka.pw.edu.pl>
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* @section LICENSE
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*
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* This file is part of GNU Radio
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*
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* GNU Radio is free software; you can redistribute it and/or modify
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 3, or (at your option)
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* any later version.
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*
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* GNU Radio is distributed in the hope that it will be useful,
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with GNU Radio; see the file COPYING. If not, write to
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* along with this program; see the file COPYING. If not, write to
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* the Free Software Foundation, Inc., 51 Franklin Street,
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* Boston, MA 02110-1301, USA.
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*/
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@ -39,7 +39,7 @@
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#define SYNC_SEARCH_RANGE 30
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#define TRAIN_SEARCH_RANGE 40
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//tutaj umieściłem funkcję która dostaje normalny pakiet + numer
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//tutaj umieściłem funkcję która dostaje normalny pakiet + numer
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//numer pakietu to numer ramki + numer szczeliny czasowej
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//w tym przykładzie po prostu wyrzuca zawartość pakietu na wyjście
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//ps. pakiety które nie mają trzech zer na początku zazwyczaj są błędnie odebrane
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@ -113,8 +113,8 @@ gsm_receiver_cf::gsm_receiver_cf(gr_feval_dd *tuner, int osr)
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d_OSR(osr),
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d_chan_imp_length(CHAN_IMP_RESP_LENGTH),
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d_tuner(tuner),
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d_samples_counter(0),
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// d_fcch_start_pos(0),
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d_counter(0),
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d_fcch_start_pos(0),
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d_freq_offset(0),
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d_burst_nr(osr),
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d_state(first_fcch_search)
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@ -134,74 +134,76 @@ gsm_receiver_cf::~gsm_receiver_cf()
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{
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}
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void gsm_receiver_cf::forecast(int noutput_items, gr_vector_int &ninput_items_required)
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void gsm_receiver_cf::forecast(int noutput_items, gr_vector_int &nitems_items_required)
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{
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ninput_items_required[0] = noutput_items * floor((TS_BITS + 2 * GUARD_PERIOD) * d_OSR);
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nitems_items_required[0] = noutput_items * floor((TS_BITS + 2 * GUARD_PERIOD) * d_OSR);
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}
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int
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gsm_receiver_cf::general_work(int noutput_items,
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gr_vector_int &ninput_items,
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gr_vector_int &nitems_items,
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gr_vector_const_void_star &input_items,
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gr_vector_void_star &output_items)
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{
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const gr_complex *in = (const gr_complex *) input_items[0];
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const gr_complex *input = (const gr_complex *) input_items[0];
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float *out = (float *) output_items[0];
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int produced_out = 0;
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float prev_freq_offset;
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int produced_out = 0; //how many output elements were produced - this isn't used yet
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//probably the gsm receiver will be changed into sink so this variable won't be necessary
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switch (d_state) {
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//bootstrapping
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//bootstrapping
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case first_fcch_search:
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if (find_fcch_burst(in, ninput_items[0])) {
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set_frequency(d_freq_offset);
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produced_out = 0;
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if (find_fcch_burst(input, nitems_items[0])) { //find frequency correction burst in the input buffer
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set_frequency(d_freq_offset); //if fcch search is successful set frequency offset
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//produced_out = 0;
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d_state = next_fcch_search;
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} else {
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produced_out = 0;
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//produced_out = 0;
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d_state = first_fcch_search;
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}
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break;
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case next_fcch_search:
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prev_freq_offset = d_freq_offset;
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if (find_fcch_burst(in, ninput_items[0])) {
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if (abs(d_freq_offset) > 100.0) {
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set_frequency(d_freq_offset);
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case next_fcch_search: { //this state is used because it takes a bunch of buffered samples
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//before previous set_frequqency cause change
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float prev_freq_offset = d_freq_offset;
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if (find_fcch_burst(input, nitems_items[0])) {
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if (abs(prev_freq_offset - d_freq_offset) > FCCH_MAX_FREQ_OFFSET) {
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set_frequency(d_freq_offset); //call set_frequncy only frequency offset change is greater than some value
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}
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d_samples_counter = 0;
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produced_out = 0;
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//produced_out = 0;
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d_state = sch_search;
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} else {
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produced_out = 0;
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//produced_out = 0;
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d_state = next_fcch_search;
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}
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break;
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}
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case sch_search: {
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gr_complex chan_imp_resp[CHAN_IMP_RESP_LENGTH*d_OSR];
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vector_complex channel_imp_resp(CHAN_IMP_RESP_LENGTH*d_OSR);
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int t1, t2, t3;
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int burst_start = 0;
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unsigned char output_binary[BURST_SIZE];
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if (find_sch_burst(in, ninput_items[0], out)) {
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burst_start = get_sch_chan_imp_resp(in, chan_imp_resp);
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detect_burst(in, chan_imp_resp, burst_start, output_binary);
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if (decode_sch(&output_binary[3], &t1, &t2, &t3, &d_ncc, &d_bcc) == 0) {
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if (find_sch_burst(nitems_items[0])) { //wait for a SCH burst
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burst_start = get_sch_chan_imp_resp(input, &channel_imp_resp[0]); //get channel impulse response from it
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detect_burst(input, &channel_imp_resp[0], burst_start, output_binary); //detect bits using MLSE detection
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if (decode_sch(&output_binary[3], &t1, &t2, &t3, &d_ncc, &d_bcc) == 0) { //decode SCH burst
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DCOUT("sch burst_start: " << burst_start);
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d_burst_nr.set(t1, t2, t3, 0);
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DCOUT("bcc: " << d_bcc << " ncc: " << d_ncc << " t1: " << t1 << " t2: " << t2 << " t3: " << t3);
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d_channel_conf.set_multiframe_type(TSC0, multiframe_51);
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konfiguruj_odbiornik();//!!
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d_channel_conf.set_burst_types(TSC0, FCCH_FRAMES, sizeof(FCCH_FRAMES) / sizeof(unsigned), fcch_burst);
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d_channel_conf.set_burst_types(TSC0, SCH_FRAMES, sizeof(SCH_FRAMES) / sizeof(unsigned), sch_burst);
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d_channel_conf.set_burst_types(TSC0, BCCH_FRAMES, sizeof(BCCH_FRAMES) / sizeof(unsigned), normal_burst);
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DCOUT("bcc: " << d_bcc << " ncc: " << d_ncc << " t1: " << t1 << " t2: " << t2 << " t3: " << t3);
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d_burst_nr.set(t1, t2, t3, 0); //set counter of bursts value
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//configure the receiver - tell him where to find which burst type
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d_channel_conf.set_multiframe_type(TSC0, multiframe_51); //in the timeslot nr.0 (TSC0) bursts changes according to t3 counter
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konfiguruj_odbiornik();//TODO: this shouldn't be here - remove it when gsm receiver's interface will be ready
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d_channel_conf.set_burst_types(TSC0, FCCH_FRAMES, sizeof(FCCH_FRAMES) / sizeof(unsigned), fcch_burst); //tell where to find fcch bursts
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d_channel_conf.set_burst_types(TSC0, SCH_FRAMES, sizeof(SCH_FRAMES) / sizeof(unsigned), sch_burst); //sch bursts
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d_channel_conf.set_burst_types(TSC0, BCCH_FRAMES, sizeof(BCCH_FRAMES) / sizeof(unsigned), normal_burst);//!and maybe normal bursts of the BCCH logical channel
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d_burst_nr++;
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consume_each(burst_start + BURST_SIZE * d_OSR);
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consume_each(burst_start + BURST_SIZE * d_OSR); //consume samples up to next guard period
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d_state = synchronized;
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} else {
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d_state = next_fcch_search;
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d_state = next_fcch_search; //if there is error in the sch burst go back to fcch search phase
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}
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} else {
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d_state = sch_search;
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@ -211,38 +213,32 @@ gsm_receiver_cf::general_work(int noutput_items,
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//in this state receiver is synchronized and it processes bursts according to burst type for given burst number
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case synchronized: {
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gr_complex chan_imp_resp[d_chan_imp_length*d_OSR];
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burst_type b_type = d_channel_conf.get_burst_type(d_burst_nr);
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vector_complex channel_imp_resp(CHAN_IMP_RESP_LENGTH*d_OSR);
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int burst_start;
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int offset = 0;
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int to_consume = 0;
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unsigned char output_binary[BURST_SIZE];
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burst_type b_type = d_channel_conf.get_burst_type(d_burst_nr); //get burst type for given burst number
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switch (b_type) {
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case fcch_burst: {
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int ii;
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int first_sample = ceil((GUARD_PERIOD + 2 * TAIL_BITS) * d_OSR) + 1;
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int last_sample = first_sample + USEFUL_BITS * d_OSR;
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double phase_sum = 0;
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for (ii = first_sample; ii < last_sample; ii++) {
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double phase_diff = compute_phase_diff(in[ii], in[ii-1]) - (M_PI / 2) / d_OSR;
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phase_sum += phase_diff;
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}
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double freq_offset = compute_freq_offset(phase_sum, last_sample - first_sample);
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const unsigned first_sample = ceil((GUARD_PERIOD + 2 * TAIL_BITS) * d_OSR) + 1;
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const unsigned last_sample = first_sample + USEFUL_BITS * d_OSR;
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double freq_offset = compute_freq_offset(input, first_sample, last_sample);
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if (abs(freq_offset) > FCCH_MAX_FREQ_OFFSET) {
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d_freq_offset -= freq_offset;
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set_frequency(d_freq_offset);
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DCOUT("adjusting frequency, new frequency offset: " << d_freq_offset << "\n");
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DCOUT("Adjusting frequency, new frequency offset: " << d_freq_offset << "\n");
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}
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}
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break;
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case sch_burst: {
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case sch_burst: {
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int t1, t2, t3, d_ncc, d_bcc;
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burst_start = get_sch_chan_imp_resp(in, chan_imp_resp);
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detect_burst(in, &d_channel_imp_resp[0], burst_start, output_binary);
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burst_start = get_sch_chan_imp_resp(input, &channel_imp_resp[0]);
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detect_burst(input, &channel_imp_resp[0], burst_start, output_binary);
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if (decode_sch(&output_binary[3], &t1, &t2, &t3, &d_ncc, &d_bcc) == 0) {
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// d_burst_nr.set(t1, t2, t3, 0);
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// d_burst_nr.set(t1, t2, t3, 0);
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DCOUT("bcc: " << d_bcc << " ncc: " << d_ncc << " t1: " << t1 << " t2: " << t2 << " t3: " << t3);
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offset = burst_start - floor((GUARD_PERIOD) * d_OSR);
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DCOUT(offset);
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@ -251,10 +247,10 @@ gsm_receiver_cf::general_work(int noutput_items,
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}
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break;
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case normal_burst:
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burst_start = get_norm_chan_imp_resp(in, chan_imp_resp, TRAIN_SEARCH_RANGE, d_bcc);
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detect_burst(in, &d_channel_imp_resp[0], burst_start, output_binary);
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przetwarzaj_normalny_pakiet(d_burst_nr, output_binary);
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case normal_burst: //?
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burst_start = get_norm_chan_imp_resp(input, &channel_imp_resp[0], TRAIN_SEARCH_RANGE, d_bcc);
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detect_burst(input, &channel_imp_resp[0], burst_start, output_binary);
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przetwarzaj_normalny_pakiet(d_burst_nr, output_binary); //TODO: this shouldn't be here - remove it when gsm receiver's interface will be ready
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break;
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case rach_burst:
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@ -264,18 +260,17 @@ gsm_receiver_cf::general_work(int noutput_items,
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//to C0 (where sch is) back and forth
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break;
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case dummy:
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burst_start = get_norm_chan_imp_resp(in, chan_imp_resp, TRAIN_SEARCH_RANGE, 8);
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detect_burst(in, &d_channel_imp_resp[0], burst_start, output_binary);
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case dummy: //?
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burst_start = get_norm_chan_imp_resp(input, &channel_imp_resp[0], TRAIN_SEARCH_RANGE, 8);
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detect_burst(input, &channel_imp_resp[0], burst_start, output_binary);
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break;
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case empty:
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break;
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}
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d_burst_nr++;
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d_burst_nr++; //?
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to_consume += TS_BITS * d_OSR + d_burst_nr.get_offset();
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to_consume += TS_BITS * d_OSR + d_burst_nr.get_offset(); //?
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consume_each(to_consume);
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}
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break;
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@ -284,29 +279,28 @@ gsm_receiver_cf::general_work(int noutput_items,
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return produced_out;
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}
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bool gsm_receiver_cf::find_fcch_burst(const gr_complex *in, const int nitems)
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bool gsm_receiver_cf::find_fcch_burst(const gr_complex *input, const int nitems)
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{
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circular_buffer_float phase_diff_buffer(FCCH_BUFFER_SIZE * d_OSR);
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float phase_diff = 0;
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gr_complex conjprod;
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int start_pos = -1;
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int hit_count = 0;
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int miss_count = 0;
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int start_pos = -1;
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float min_phase_diff;
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float max_phase_diff;
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double best_sum = 0;
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float lowest_max_min_diff = 99999;
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int to_consume = 0;
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int sample_number = 0;
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bool end = false;
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bool result = false;
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double freq_offset;
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circular_buffer_float::iterator buffer_iter;
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//?
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enum states {
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init, search, found_something, fcch_found, search_fail
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init, search, found_something, fcch_found, search_fail //?
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} fcch_search_state;
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fcch_search_state = init;
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@ -331,7 +325,7 @@ bool gsm_receiver_cf::find_fcch_burst(const gr_complex *in, const int nitems)
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to_consume = sample_number;
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fcch_search_state = search_fail;
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} else {
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phase_diff = compute_phase_diff(in[sample_number], in[sample_number-1]);
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phase_diff = compute_phase_diff(input[sample_number], input[sample_number-1]);
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if (phase_diff > 0) {
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to_consume = sample_number;
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@ -343,65 +337,69 @@ bool gsm_receiver_cf::find_fcch_burst(const gr_complex *in, const int nitems)
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break;
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case found_something:
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if (phase_diff > 0) {
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hit_count++;
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} else {
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miss_count++;
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}
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case found_something: {
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if ((miss_count >= FCCH_MAX_MISSES * d_OSR) && (hit_count <= FCCH_HITS_NEEDED * d_OSR)) {
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fcch_search_state = init;
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continue;
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} else if (((miss_count >= FCCH_MAX_MISSES * d_OSR) && (hit_count > FCCH_HITS_NEEDED * d_OSR)) || (hit_count > 2 * FCCH_HITS_NEEDED * d_OSR)) {
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fcch_search_state = fcch_found;
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continue;
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} else if ((miss_count < FCCH_MAX_MISSES * d_OSR) && (hit_count > FCCH_HITS_NEEDED * d_OSR)) {
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//find difference between minimal and maximal element in the buffer
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//for FCCH this value should be low
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//this part is searching for a region where this value is lowest
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min_phase_diff = * (min_element(phase_diff_buffer.begin(), phase_diff_buffer.end()));
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max_phase_diff = * (max_element(phase_diff_buffer.begin(), phase_diff_buffer.end()));
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if (phase_diff > 0) {
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hit_count++;
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} else {
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miss_count++;
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}
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if (lowest_max_min_diff > max_phase_diff - min_phase_diff) {
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lowest_max_min_diff = max_phase_diff - min_phase_diff;
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start_pos = sample_number - FCCH_HITS_NEEDED * d_OSR - FCCH_MAX_MISSES * d_OSR;
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best_sum = 0;
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if ((miss_count >= FCCH_MAX_MISSES * d_OSR) && (hit_count <= FCCH_HITS_NEEDED * d_OSR)) {
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fcch_search_state = init;
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continue;
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} else if (((miss_count >= FCCH_MAX_MISSES * d_OSR) && (hit_count > FCCH_HITS_NEEDED * d_OSR)) || (hit_count > 2 * FCCH_HITS_NEEDED * d_OSR)) {
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fcch_search_state = fcch_found;
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continue;
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} else if ((miss_count < FCCH_MAX_MISSES * d_OSR) && (hit_count > FCCH_HITS_NEEDED * d_OSR)) {
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//find difference between minimal and maximal element in the buffer
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//for FCCH this value should be low
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//this part is searching for a region where this value is lowest
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min_phase_diff = * (min_element(phase_diff_buffer.begin(), phase_diff_buffer.end()));
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max_phase_diff = * (max_element(phase_diff_buffer.begin(), phase_diff_buffer.end()));
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for (buffer_iter = phase_diff_buffer.begin();
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buffer_iter != (phase_diff_buffer.end());
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buffer_iter++) {
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best_sum += *buffer_iter - (M_PI / 2) / d_OSR;
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if (lowest_max_min_diff > max_phase_diff - min_phase_diff) {
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lowest_max_min_diff = max_phase_diff - min_phase_diff;
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start_pos = sample_number - FCCH_HITS_NEEDED * d_OSR - FCCH_MAX_MISSES * d_OSR;
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best_sum = 0;
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for (buffer_iter = phase_diff_buffer.begin();
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buffer_iter != (phase_diff_buffer.end());
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buffer_iter++) {
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best_sum += *buffer_iter - (M_PI / 2) / d_OSR;
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}
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}
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}
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sample_number++;
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if (sample_number >= nitems) {
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fcch_search_state = search_fail;
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continue;
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}
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|
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phase_diff = compute_phase_diff(input[sample_number], input[sample_number-1]);
|
||||
phase_diff_buffer.push_back(phase_diff);
|
||||
fcch_search_state = found_something;
|
||||
}
|
||||
|
||||
sample_number++;
|
||||
|
||||
if (sample_number >= nitems) {
|
||||
fcch_search_state = search_fail;
|
||||
continue;
|
||||
}
|
||||
|
||||
phase_diff = compute_phase_diff(in[sample_number], in[sample_number-1]);
|
||||
phase_diff_buffer.push_back(phase_diff);
|
||||
fcch_search_state = found_something;
|
||||
|
||||
break;
|
||||
|
||||
case fcch_found:
|
||||
// DCOUT("fcch found on position: " << d_samples_counter + start_pos);
|
||||
DCOUT("fcch found on position: " << start_pos);
|
||||
to_consume = start_pos + FCCH_HITS_NEEDED * d_OSR + 1;
|
||||
case fcch_found: {
|
||||
DCOUT("fcch found on position: " << d_counter + start_pos);
|
||||
to_consume = start_pos + FCCH_HITS_NEEDED * d_OSR + 1;
|
||||
|
||||
// d_fcch_start_pos = d_samples_counter + start_pos;
|
||||
freq_offset = compute_freq_offset(best_sum, FCCH_HITS_NEEDED);
|
||||
d_freq_offset -= freq_offset;
|
||||
DCOUT("freq_offset: " << d_freq_offset);
|
||||
d_fcch_start_pos = d_counter + start_pos;
|
||||
|
||||
end = true;
|
||||
result = true;
|
||||
break;
|
||||
//compute frequency offset
|
||||
double phase_offset = best_sum / FCCH_HITS_NEEDED;
|
||||
double freq_offset = phase_offset * 1625000.0 / (12.0 * M_PI);
|
||||
d_freq_offset -= freq_offset;
|
||||
DCOUT("freq_offset: " << d_freq_offset);
|
||||
|
||||
end = true;
|
||||
result = true;
|
||||
break;
|
||||
}
|
||||
|
||||
case search_fail:
|
||||
end = true;
|
||||
|
@ -410,17 +408,24 @@ bool gsm_receiver_cf::find_fcch_burst(const gr_complex *in, const int nitems)
|
|||
}
|
||||
}
|
||||
|
||||
// d_samples_counter += to_consume;
|
||||
d_counter += to_consume;
|
||||
consume_each(to_consume);
|
||||
|
||||
return result;
|
||||
}
|
||||
|
||||
double gsm_receiver_cf::compute_freq_offset(double best_sum, unsigned denominator)
|
||||
double gsm_receiver_cf::compute_freq_offset(const gr_complex * input, unsigned first_sample, unsigned last_sample)
|
||||
{
|
||||
float phase_offset, freq_offset;
|
||||
phase_offset = best_sum / denominator;
|
||||
freq_offset = phase_offset * 1625000.0 / (12.0 * M_PI);
|
||||
double phase_sum = 0;
|
||||
unsigned ii;
|
||||
|
||||
for (ii = first_sample; ii < last_sample; ii++) {
|
||||
double phase_diff = compute_phase_diff(input[ii], input[ii-1]) - (M_PI / 2) / d_OSR;
|
||||
phase_sum += phase_diff;
|
||||
}
|
||||
|
||||
double phase_offset = phase_sum / (last_sample - first_sample);
|
||||
double freq_offset = phase_offset * 1625000.0 / (12.0 * M_PI);
|
||||
return freq_offset;
|
||||
}
|
||||
|
||||
|
@ -435,14 +440,13 @@ inline float gsm_receiver_cf::compute_phase_diff(gr_complex val1, gr_complex val
|
|||
return gr_fast_atan2f(imag(conjprod), real(conjprod));
|
||||
}
|
||||
|
||||
bool gsm_receiver_cf::find_sch_burst(const gr_complex *in, const int nitems , float *out)
|
||||
bool gsm_receiver_cf::find_sch_burst(const int nitems)
|
||||
{
|
||||
int to_consume = 0;
|
||||
bool end = false;
|
||||
bool result = false;
|
||||
// unsigned sample_nr_near_sch_start = d_fcch_start_pos + (FRAME_BITS - SAFETY_MARGIN) * d_OSR;
|
||||
const unsigned sample_nr_near_sch_start = (FRAME_BITS - SAFETY_MARGIN + TS_BITS) * d_OSR;
|
||||
|
||||
unsigned sample_nr_near_sch_start = d_fcch_start_pos + (FRAME_BITS - SAFETY_MARGIN) * d_OSR;
|
||||
|
||||
enum states {
|
||||
start, reach_sch, search_not_finished, sch_found
|
||||
} sch_search_state;
|
||||
|
@ -453,7 +457,7 @@ bool gsm_receiver_cf::find_sch_burst(const gr_complex *in, const int nitems , fl
|
|||
switch (sch_search_state) {
|
||||
|
||||
case start:
|
||||
if (d_samples_counter < sample_nr_near_sch_start) {
|
||||
if (d_counter < sample_nr_near_sch_start) {
|
||||
sch_search_state = reach_sch;
|
||||
} else {
|
||||
sch_search_state = sch_found;
|
||||
|
@ -461,8 +465,8 @@ bool gsm_receiver_cf::find_sch_burst(const gr_complex *in, const int nitems , fl
|
|||
break;
|
||||
|
||||
case reach_sch:
|
||||
if (d_samples_counter + nitems >= sample_nr_near_sch_start) {
|
||||
to_consume = sample_nr_near_sch_start - d_samples_counter;
|
||||
if (d_counter + nitems >= sample_nr_near_sch_start) {
|
||||
to_consume = sample_nr_near_sch_start - d_counter;
|
||||
} else {
|
||||
to_consume = nitems;
|
||||
}
|
||||
|
@ -482,12 +486,12 @@ bool gsm_receiver_cf::find_sch_burst(const gr_complex *in, const int nitems , fl
|
|||
}
|
||||
}
|
||||
|
||||
d_samples_counter += to_consume;
|
||||
d_counter += to_consume;
|
||||
consume_each(to_consume);
|
||||
return result;
|
||||
}
|
||||
|
||||
int gsm_receiver_cf::get_sch_chan_imp_resp(const gr_complex *in, gr_complex * chan_imp_resp)
|
||||
int gsm_receiver_cf::get_sch_chan_imp_resp(const gr_complex *input, gr_complex * chan_imp_resp)
|
||||
{
|
||||
vector_complex correlation_buffer;
|
||||
vector_float power_buffer;
|
||||
|
@ -500,7 +504,7 @@ int gsm_receiver_cf::get_sch_chan_imp_resp(const gr_complex *in, gr_complex * ch
|
|||
float energy = 0;
|
||||
|
||||
for (int ii = SYNC_POS * d_OSR; ii < (SYNC_POS + SYNC_SEARCH_RANGE) *d_OSR; ii++) {
|
||||
gr_complex correlation = correlate_sequence(&d_sch_training_seq[5], &in[ii], N_SYNC_BITS - 10);
|
||||
gr_complex correlation = correlate_sequence(&d_sch_training_seq[5], N_SYNC_BITS - 10, &input[ii]);
|
||||
correlation_buffer.push_back(correlation);
|
||||
power_buffer.push_back(pow(abs(correlation), 2));
|
||||
}
|
||||
|
@ -527,7 +531,7 @@ int gsm_receiver_cf::get_sch_chan_imp_resp(const gr_complex *in, gr_complex * ch
|
|||
}
|
||||
|
||||
strongest_window_nr = max_element(window_energy_buffer.begin(), window_energy_buffer.end()) - window_energy_buffer.begin();
|
||||
d_channel_imp_resp.clear();
|
||||
// d_channel_imp_resp.clear();
|
||||
|
||||
max_correlation = 0;
|
||||
for (int ii = 0; ii < (d_chan_imp_length) *d_OSR; ii++) {
|
||||
|
@ -536,7 +540,7 @@ int gsm_receiver_cf::get_sch_chan_imp_resp(const gr_complex *in, gr_complex * ch
|
|||
chan_imp_resp_center = ii;
|
||||
max_correlation = abs(correlation);
|
||||
}
|
||||
d_channel_imp_resp.push_back(correlation);
|
||||
// d_channel_imp_resp.push_back(correlation);
|
||||
chan_imp_resp[ii] = correlation;
|
||||
}
|
||||
|
||||
|
@ -544,7 +548,7 @@ int gsm_receiver_cf::get_sch_chan_imp_resp(const gr_complex *in, gr_complex * ch
|
|||
return burst_start;
|
||||
}
|
||||
|
||||
void gsm_receiver_cf::detect_burst(const gr_complex * in, gr_complex * chan_imp_resp, int burst_start, unsigned char * output_binary)
|
||||
void gsm_receiver_cf::detect_burst(const gr_complex * input, gr_complex * chan_imp_resp, int burst_start, unsigned char * output_binary)
|
||||
{
|
||||
float output[BURST_SIZE];
|
||||
gr_complex rhh_temp[CHAN_IMP_RESP_LENGTH*d_OSR];
|
||||
|
@ -558,7 +562,7 @@ void gsm_receiver_cf::detect_burst(const gr_complex * in, gr_complex * chan_imp_
|
|||
rhh[ii] = conj(rhh_temp[ii*d_OSR]);
|
||||
}
|
||||
|
||||
mafi(&in[burst_start], BURST_SIZE, chan_imp_resp, d_chan_imp_length*d_OSR, filtered_burst);
|
||||
mafi(&input[burst_start], BURST_SIZE, chan_imp_resp, d_chan_imp_length*d_OSR, filtered_burst);
|
||||
|
||||
viterbi_detector(filtered_burst, BURST_SIZE, rhh, start_state, stop_states, 2, output);
|
||||
|
||||
|
@ -568,7 +572,7 @@ void gsm_receiver_cf::detect_burst(const gr_complex * in, gr_complex * chan_imp_
|
|||
}
|
||||
|
||||
//TODO consider placing this funtion in a separate class for signal processing
|
||||
void gsm_receiver_cf::gmsk_mapper(const unsigned char * input, int ninput, gr_complex * gmsk_output, gr_complex start_point)
|
||||
void gsm_receiver_cf::gmsk_mapper(const unsigned char * input, int nitems, gr_complex * gmsk_output, gr_complex start_point)
|
||||
{
|
||||
gr_complex j = gr_complex(0.0, 1.0);
|
||||
|
||||
|
@ -577,7 +581,7 @@ void gsm_receiver_cf::gmsk_mapper(const unsigned char * input, int ninput, gr_co
|
|||
int previous_symbol = 2 * input[0] - 1;
|
||||
gmsk_output[0] = start_point;
|
||||
|
||||
for (int i = 1; i < ninput; i++) {
|
||||
for (int i = 1; i < nitems; i++) {
|
||||
//change bits representation to NRZ
|
||||
current_symbol = 2 * input[i] - 1;
|
||||
//differentially encode
|
||||
|
@ -589,45 +593,45 @@ void gsm_receiver_cf::gmsk_mapper(const unsigned char * input, int ninput, gr_co
|
|||
}
|
||||
|
||||
//TODO consider use of some generalized function for correlation and placing it in a separate class for signal processing
|
||||
gr_complex gsm_receiver_cf::correlate_sequence(const gr_complex * sequence, const gr_complex * input_signal, int length)
|
||||
gr_complex gsm_receiver_cf::correlate_sequence(const gr_complex * sequence, int length, const gr_complex * input)
|
||||
{
|
||||
gr_complex result(0.0, 0.0);
|
||||
int sample_number = 0;
|
||||
|
||||
for (int ii = 0; ii < length; ii++) {
|
||||
sample_number = (ii * d_OSR) ;
|
||||
result += sequence[ii] * conj(input_signal[sample_number]);
|
||||
result += sequence[ii] * conj(input[sample_number]);
|
||||
}
|
||||
|
||||
result = result / gr_complex(length, 0);
|
||||
return result;
|
||||
}
|
||||
|
||||
//computes autocorrelation for positive values
|
||||
//computes autocorrelation for positive arguments
|
||||
//TODO consider placing this funtion in a separate class for signal processing
|
||||
inline void gsm_receiver_cf::autocorrelation(const gr_complex * input, gr_complex * out, int length)
|
||||
inline void gsm_receiver_cf::autocorrelation(const gr_complex * input, gr_complex * out, int nitems)
|
||||
{
|
||||
int i, k;
|
||||
for (k = length - 1; k >= 0; k--) {
|
||||
for (k = nitems - 1; k >= 0; k--) {
|
||||
out[k] = gr_complex(0, 0);
|
||||
for (i = k; i < length; i++) {
|
||||
for (i = k; i < nitems; i++) {
|
||||
out[k] += input[i] * conj(input[i-k]);
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
//TODO consider use of some generalized function for filtering and placing it in a separate class for signal processing
|
||||
inline void gsm_receiver_cf::mafi(const gr_complex * input, int input_length, gr_complex * filter, int filter_length, gr_complex * output)
|
||||
inline void gsm_receiver_cf::mafi(const gr_complex * input, int nitems, gr_complex * filter, int filter_length, gr_complex * output)
|
||||
{
|
||||
int ii = 0, n, a;
|
||||
|
||||
for (n = 0; n < input_length; n++) {
|
||||
for (n = 0; n < nitems; n++) {
|
||||
a = n * d_OSR;
|
||||
output[n] = 0;
|
||||
ii = 0;
|
||||
|
||||
while (ii < filter_length) {
|
||||
if ((a + ii) >= input_length*d_OSR)
|
||||
if ((a + ii) >= nitems*d_OSR)
|
||||
break;
|
||||
output[n] += input[a+ii] * filter[ii];
|
||||
ii++;
|
||||
|
@ -635,7 +639,7 @@ inline void gsm_receiver_cf::mafi(const gr_complex * input, int input_length, gr
|
|||
}
|
||||
}
|
||||
|
||||
int gsm_receiver_cf::get_norm_chan_imp_resp(const gr_complex *in, gr_complex * chan_imp_resp, unsigned search_range, int bcc)
|
||||
int gsm_receiver_cf::get_norm_chan_imp_resp(const gr_complex *input, gr_complex * chan_imp_resp, unsigned search_range, int bcc)
|
||||
{
|
||||
vector_complex correlation_buffer;
|
||||
vector_float power_buffer;
|
||||
|
@ -652,7 +656,7 @@ int gsm_receiver_cf::get_norm_chan_imp_resp(const gr_complex *in, gr_complex * c
|
|||
int search_stop_pos = search_center + d_chan_imp_length * d_OSR + 2 * d_OSR;
|
||||
|
||||
for (int ii = search_start_pos; ii < search_stop_pos; ii++) {
|
||||
gr_complex correlation = correlate_sequence(&d_norm_training_seq[bcc][TRAIN_BEGINNING], &in[ii], N_TRAIN_BITS - 10);
|
||||
gr_complex correlation = correlate_sequence(&d_norm_training_seq[bcc][TRAIN_BEGINNING], N_TRAIN_BITS - 10, &input[ii]);
|
||||
|
||||
correlation_buffer.push_back(correlation);
|
||||
power_buffer.push_back(pow(abs(correlation), 2));
|
||||
|
@ -681,7 +685,7 @@ int gsm_receiver_cf::get_norm_chan_imp_resp(const gr_complex *in, gr_complex * c
|
|||
}
|
||||
|
||||
strongest_window_nr = max_element(window_energy_buffer.begin(), window_energy_buffer.end()) - window_energy_buffer.begin();
|
||||
d_channel_imp_resp.clear();
|
||||
// d_channel_imp_resp.clear();
|
||||
|
||||
max_correlation = 0;
|
||||
for (int ii = 0; ii < (d_chan_imp_length)*d_OSR; ii++) {
|
||||
|
@ -690,7 +694,7 @@ int gsm_receiver_cf::get_norm_chan_imp_resp(const gr_complex *in, gr_complex * c
|
|||
chan_imp_resp_center = ii;
|
||||
max_correlation = abs(correlation);
|
||||
}
|
||||
d_channel_imp_resp.push_back(correlation);
|
||||
// d_channel_imp_resp.push_back(correlation);
|
||||
chan_imp_resp[ii] = correlation;
|
||||
}
|
||||
// We want to use the first sample of the impulseresponse, and the
|
||||
|
|
Loading…
Reference in New Issue