340 lines
10 KiB
C++
340 lines
10 KiB
C++
/*
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* (C) 2022 by sysmocom s.f.m.c. GmbH <info@sysmocom.de>
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* All Rights Reserved
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*
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* Author: Eric Wild <ewild@sysmocom.de>
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*
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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 Affero General Public License as published by
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* the Free Software Foundation; either version 3 of the License, or
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* (at your option) any later version.
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*
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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 Affero General Public License for more details.
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*
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* You should have received a copy of the GNU Affero General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*
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*/
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#include "sigProcLib.h"
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#include "signalVector.h"
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#include <atomic>
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#include <cassert>
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#include <complex>
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#include <iostream>
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#include <future>
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#include "ms.h"
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#include "grgsm_vitac/grgsm_vitac.h"
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extern "C" {
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#include "sch.h"
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}
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#ifdef LOG
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#undef LOG
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#endif
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#if !defined(SYNCTHINGONLY) //|| !defined(NODAMNLOG)
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#define DBGLG(...) ms_trx::dummy_log()
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#else
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#define DBGLG(...) std::cerr
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#endif
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#if !defined(SYNCTHINGONLY) || !defined(NODAMNLOG)
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#define DBGLG2(...) ms_trx::dummy_log()
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#else
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#define DBGLG2(...) std::cerr
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#endif
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#define PRINT_Q_OVERFLOW
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bool ms_trx::decode_sch(float *bits, bool update_global_clock)
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{
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int fn;
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struct sch_info sch;
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ubit_t info[GSM_SCH_INFO_LEN];
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sbit_t data[GSM_SCH_CODED_LEN];
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float_to_sbit(&bits[3], &data[0], 1, 39);
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float_to_sbit(&bits[106], &data[39], 1, 39);
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if (!gsm_sch_decode(info, data)) {
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gsm_sch_parse(info, &sch);
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if (update_global_clock) {
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DBGLG() << "SCH : Decoded values" << std::endl;
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DBGLG() << " BSIC: " << sch.bsic << std::endl;
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DBGLG() << " TSC: " << (sch.bsic & 0x7) << std::endl;
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DBGLG() << " T1 : " << sch.t1 << std::endl;
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DBGLG() << " T2 : " << sch.t2 << std::endl;
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DBGLG() << " T3p : " << sch.t3p << std::endl;
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DBGLG() << " FN : " << gsm_sch_to_fn(&sch) << std::endl;
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}
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fn = gsm_sch_to_fn(&sch);
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if (fn < 0) { // how? wh?
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DBGLG() << "SCH : Failed to convert FN " << std::endl;
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return false;
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}
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if (update_global_clock) {
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mBSIC = sch.bsic;
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mTSC = sch.bsic & 0x7;
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timekeeper.set(fn, 0);
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// global_time_keeper.FN(fn);
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// global_time_keeper.TN(0);
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}
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#ifdef SYNCTHINGONLY
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else {
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int t3 = sch.t3p * 10 + 1;
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if (t3 == 11) {
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// timeslot hitter attempt @ fn 21 in mf
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DBGLG2() << "sch @ " << t3 << std::endl;
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auto e = GSM::Time(fn, 0);
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e += 10;
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ts_hitter_q.spsc_push(&e);
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}
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}
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#endif
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return true;
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}
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return false;
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}
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void ms_trx::maybe_update_gain(one_burst &brst)
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{
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static_assert((sizeof(brst.burst) / sizeof(brst.burst[0])) == ONE_TS_BURST_LEN, "wtf, buffer size mismatch?");
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const int avgburst_num = 8 * 20; // ~ 50*4.5ms = 90ms?
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static_assert(avgburst_num * 577 > (50 * 1000), "can't update faster then blade wait time?");
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const unsigned int rx_max_cutoff = (rxFullScale * 2) / 3;
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static int gain_check = 0;
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static float runmean = 0;
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float sum = 0;
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for (auto i : brst.burst)
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sum += abs(i.real()) + abs(i.imag());
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sum /= ONE_TS_BURST_LEN * 2;
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runmean = gain_check ? (runmean * (gain_check + 2) - 1 + sum) / (gain_check + 2) : sum;
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if (gain_check == avgburst_num - 1) {
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DBGLG2() << "\x1B[32m #RXG \033[0m" << rxgain << " " << runmean << " " << sum << std::endl;
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auto gainoffset = runmean < (rxFullScale / 4 ? 4 : 2);
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gainoffset = runmean < (rxFullScale / 2 ? 2 : 1);
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float newgain = runmean < rx_max_cutoff ? rxgain + gainoffset : rxgain - gainoffset;
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// FIXME: gian cutoff
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if (newgain != rxgain && newgain <= 60)
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std::thread([this, newgain] { setRxGain(newgain); }).detach();
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runmean = 0;
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}
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gain_check = (gain_check + 1) % avgburst_num;
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}
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static char sch_demod_bits[148];
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bool ms_trx::handle_sch_or_nb()
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{
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one_burst brst;
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const auto current_gsm_time = timekeeper.gsmtime();
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const auto is_sch = gsm_sch_check_ts(current_gsm_time.TN(), current_gsm_time.FN());
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//either pass burst to upper layer for demod, OR pass demodded SCH to upper layer so we don't waste time processing it twice
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brst.gsmts = current_gsm_time;
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if (!is_sch) {
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memcpy(brst.burst, burst_copy_buffer, sizeof(blade_sample_type) * ONE_TS_BURST_LEN);
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} else {
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handle_sch(false);
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memcpy(brst.sch_bits, sch_demod_bits, sizeof(sch_demod_bits));
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}
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#ifndef SYNCTHINGONLY
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if (upper_is_ready) { // this is blocking, so only submit if there is a reader - only if upper exists!
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#endif
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while (!rxqueue.spsc_push(&brst))
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;
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#ifndef SYNCTHINGONLY
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}
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#endif
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if (do_auto_gain)
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maybe_update_gain(brst);
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return false;
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}
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static float sch_acq_buffer[SCH_LEN_SPS * 2];
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bool ms_trx::handle_sch(bool is_first_sch_acq)
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{
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auto current_gsm_time = timekeeper.gsmtime();
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const auto buf_len = is_first_sch_acq ? SCH_LEN_SPS : ONE_TS_BURST_LEN;
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const auto which_in_buffer = is_first_sch_acq ? first_sch_buf : burst_copy_buffer;
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const auto which_out_buffer = is_first_sch_acq ? sch_acq_buffer : &sch_acq_buffer[40 * 2];
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const auto ss = reinterpret_cast<std::complex<float> *>(which_out_buffer);
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std::complex<float> channel_imp_resp[CHAN_IMP_RESP_LENGTH * d_OSR];
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int start;
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memset((void *)&sch_acq_buffer[0], 0, sizeof(sch_acq_buffer));
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if (is_first_sch_acq) {
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float max_corr = 0;
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convert_and_scale(which_out_buffer, which_in_buffer, buf_len * 2, 1.f / float(rxFullScale));
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start = get_sch_buffer_chan_imp_resp(ss, &channel_imp_resp[0], buf_len, &max_corr);
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detect_burst(&ss[start], &channel_imp_resp[0], 0, sch_demod_bits);
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} else {
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convert_and_scale(which_out_buffer, which_in_buffer, buf_len * 2, 1.f / float(rxFullScale));
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start = get_sch_chan_imp_resp(ss, &channel_imp_resp[0]);
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start = start < 39 ? start : 39;
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start = start > -39 ? start : -39;
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detect_burst(&ss[start], &channel_imp_resp[0], 0, sch_demod_bits);
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}
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SoftVector bitss(148);
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for (int i = 0; i < 148; i++) {
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bitss[i] = (sch_demod_bits[i]);
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}
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auto sch_decode_success = decode_sch(bitss.begin(), is_first_sch_acq);
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if (sch_decode_success) {
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const auto ts_offset_symb = 0;
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if (is_first_sch_acq) {
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// update ts to first sample in sch buffer, to allow delay calc for current ts
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first_sch_ts_start = first_sch_buf_rcv_ts + start - (ts_offset_symb * 4) - 1;
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} else if (abs(start) > 1) {
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// continuous sch tracking, only update if off too much
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temp_ts_corr_offset += -start;
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std::cerr << "offs: " << start << " " << temp_ts_corr_offset << std::endl;
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}
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return true;
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} else {
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DBGLG2() << "L SCH : \x1B[31m decode fail \033[0m @ toa:" << start << " " << current_gsm_time.FN()
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<< ":" << current_gsm_time.TN() << std::endl;
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}
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return false;
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}
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SCH_STATE ms_trx::search_for_sch(dev_buf_t *rcd)
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{
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static unsigned int sch_pos = 0;
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if (sch_thread_done)
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return SCH_STATE::FOUND;
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if (rcv_done)
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return SCH_STATE::SEARCHING;
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auto to_copy = SCH_LEN_SPS - sch_pos;
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if (SCH_LEN_SPS == to_copy) // first time
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first_sch_buf_rcv_ts = rcd->get_first_ts();
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if (!to_copy) {
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sch_pos = 0;
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rcv_done = true;
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std::thread([this] {
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set_name_aff_sched("sch_search", 1, SCHED_FIFO, sched_get_priority_max(SCHED_FIFO) - 5);
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auto ptr = reinterpret_cast<const int16_t *>(first_sch_buf);
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const auto target_val = rxFullScale / 8;
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float sum = 0;
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for (unsigned int i = 0; i < SCH_LEN_SPS * 2; i++)
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sum += std::abs(ptr[i]);
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sum /= SCH_LEN_SPS * 2;
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//FIXME: arbitrary value, gain cutoff
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if (sum > target_val || rxgain >= 60) // enough ?
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sch_thread_done = this->handle_sch(true);
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else {
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std::cerr << "\x1B[32m #RXG \033[0m gain " << rxgain << " -> " << rxgain + 4
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<< " sample avg:" << sum << " target: >=" << target_val << std::endl;
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setRxGain(rxgain + 4);
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}
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if (!sch_thread_done)
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rcv_done = false; // retry!
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return (bool)sch_thread_done;
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}).detach();
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}
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auto spsmax = rcd->actual_samples_per_buffer();
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if (to_copy > (unsigned int)spsmax)
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sch_pos += rcd->readall(first_sch_buf + sch_pos);
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else
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sch_pos += rcd->read_n(first_sch_buf + sch_pos, 0, to_copy);
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return SCH_STATE::SEARCHING;
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}
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void ms_trx::grab_bursts(dev_buf_t *rcd)
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{
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// partial burst samples read from the last buffer
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static int partial_rdofs = 0;
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static bool first_call = true;
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int to_skip = 0;
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// round up to next burst by calculating the time between sch detection and now
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if (first_call) {
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const auto next_burst_start = rcd->get_first_ts() - first_sch_ts_start;
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const auto fullts = next_burst_start / ONE_TS_BURST_LEN;
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const auto fracts = next_burst_start % ONE_TS_BURST_LEN;
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to_skip = ONE_TS_BURST_LEN - fracts;
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for (unsigned int i = 0; i < fullts; i++)
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timekeeper.inc_and_update(first_sch_ts_start + i * ONE_TS_BURST_LEN);
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if (fracts)
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timekeeper.inc_both();
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// timekeeper.inc_and_update(first_sch_ts_start + 1 * ONE_TS_BURST_LEN);
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timekeeper.dec_by_one(); // oops, off by one?
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timekeeper.set(timekeeper.gsmtime(), rcd->get_first_ts() - ONE_TS_BURST_LEN + to_skip);
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DBGLG() << "this ts: " << rcd->get_first_ts() << " diff full TN: " << fullts << " frac TN: " << fracts
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<< " GSM now: " << timekeeper.gsmtime().FN() << ":" << timekeeper.gsmtime().TN() << " is sch? "
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<< gsm_sch_check_fn(timekeeper.gsmtime().FN()) << std::endl;
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first_call = false;
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}
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if (partial_rdofs) {
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auto first_remaining = ONE_TS_BURST_LEN - partial_rdofs;
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auto rd = rcd->read_n(burst_copy_buffer + partial_rdofs, 0, first_remaining);
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if (rd != (int)first_remaining) {
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partial_rdofs += rd;
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return;
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}
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timekeeper.inc_and_update_safe(rcd->get_first_ts() - partial_rdofs);
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handle_sch_or_nb();
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to_skip = first_remaining;
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}
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// apply sample rate slippage compensation
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to_skip -= temp_ts_corr_offset;
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// FIXME: happens rarely, read_n start -1 blows up
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// this is fine: will just be corrected one buffer later
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if (to_skip < 0)
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to_skip = 0;
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else
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temp_ts_corr_offset = 0;
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const auto left_after_burst = rcd->actual_samples_per_buffer() - to_skip;
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const int full = left_after_burst / ONE_TS_BURST_LEN;
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const int frac = left_after_burst % ONE_TS_BURST_LEN;
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for (int i = 0; i < full; i++) {
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rcd->read_n(burst_copy_buffer, to_skip + i * ONE_TS_BURST_LEN, ONE_TS_BURST_LEN);
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timekeeper.inc_and_update_safe(rcd->get_first_ts() + to_skip + i * ONE_TS_BURST_LEN);
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handle_sch_or_nb();
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}
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if (frac)
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rcd->read_n(burst_copy_buffer, to_skip + full * ONE_TS_BURST_LEN, frac);
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partial_rdofs = frac;
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}
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