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Diffstat (limited to 'lib/transmitter/txtime_setter_impl.cc')
| -rw-r--r-- | lib/transmitter/txtime_setter_impl.cc | 196 |
1 files changed, 196 insertions, 0 deletions
diff --git a/lib/transmitter/txtime_setter_impl.cc b/lib/transmitter/txtime_setter_impl.cc new file mode 100644 index 0000000..33bc994 --- /dev/null +++ b/lib/transmitter/txtime_setter_impl.cc @@ -0,0 +1,196 @@ +/* -*- c++ -*- */ +/* @file + * @author Piotr Krysik <ptrkrysik@gmail.com> + * @author Vadim Yanitskiy <axilirator@gmail.com> + * @section LICENSE + * + * Gr-gsm 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. + * + * Gr-gsm 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 gr-gsm; 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 <gnuradio/io_signature.h> +#include <grgsm/gsmtap.h> + +#include "txtime_setter_impl.h" + +#define UNKNOWN_FN 0xffffffff +#define MAX_EARLY_TIME_DIFF 10.0 + +namespace gr { + namespace gsm { + + txtime_setter::sptr + txtime_setter::make( + uint32_t init_fn, uint64_t init_time_secs, + double init_time_fracs, uint64_t time_hint_secs, + double time_hint_fracs, double timing_advance, + double delay_correction) + { + return gnuradio::get_initial_sptr + (new txtime_setter_impl(init_fn, init_time_secs, + init_time_fracs, time_hint_secs, time_hint_fracs, + timing_advance, delay_correction)); + } + + /* + * The private constructor + */ + txtime_setter_impl::txtime_setter_impl( + uint32_t init_fn, uint64_t init_time_secs, + double init_time_fracs, uint64_t time_hint_secs, + double time_hint_fracs, double timing_advance, + double delay_correction + ) : gr::block("txtime_setter", + gr::io_signature::make(0, 0, 0), + gr::io_signature::make(0, 0, 0)), + d_time_hint(time_hint_secs,time_hint_fracs), + d_time_ref(init_time_secs,init_time_fracs), + d_delay_correction(delay_correction), + d_timing_advance(timing_advance), + d_fn_ref(init_fn), + d_ts_ref(0) + { + // Register I/O ports + message_port_register_in(pmt::mp("fn_time")); + message_port_register_in(pmt::mp("bursts_in")); + message_port_register_out(pmt::mp("bursts_out")); + + // Bind message handlers + set_msg_handler(pmt::mp("fn_time"), + boost::bind(&txtime_setter_impl::process_fn_time_reference, + this, _1)); + set_msg_handler(pmt::mp("bursts_in"), + boost::bind(&txtime_setter_impl::process_txtime_of_burst, + this, _1)); + } + + /* + * Our virtual destructor. + */ + txtime_setter_impl::~txtime_setter_impl() + { + } + + void txtime_setter_impl::process_fn_time_reference(pmt::pmt_t msg) + { + pmt::pmt_t not_found = pmt::intern("not_found"); + pmt::pmt_t fn_time, time_hint; + + fn_time = pmt::dict_ref(msg, + pmt::intern("fn_time"), not_found); + time_hint = pmt::dict_ref(msg, + pmt::intern("fn_time"), not_found); + + if (fn_time != not_found) { + uint32_t fn_ref = static_cast<uint32_t> + (pmt::to_uint64(pmt::car(pmt::car(fn_time)))); + uint32_t ts = static_cast<uint32_t> + (pmt::to_uint64(pmt::cdr(pmt::car(fn_time)))); + uint64_t time_secs = pmt::to_uint64( + pmt::car(pmt::cdr(fn_time))); + double time_fracs = pmt::to_double( + pmt::cdr(pmt::cdr(fn_time))); + + set_fn_time_reference(fn_ref, ts, time_secs, time_fracs); + } else if (time_hint != not_found) { + set_time_hint(pmt::to_uint64(pmt::car(fn_time)), + pmt::to_double(pmt::cdr(fn_time))); + } + } + + void txtime_setter_impl::process_txtime_of_burst(pmt::pmt_t msg_in) + { + if (d_fn_ref != UNKNOWN_FN) + { + pmt::pmt_t blob = pmt::cdr(msg_in); + + // Extract GSMTAP header from message + gsmtap_hdr *header = (gsmtap_hdr *) pmt::blob_data(blob); + uint32_t frame_nr = be32toh(header->frame_number); + uint32_t ts_num = header->timeslot; + + time_format txtime = fn_time_delta_cpp(d_fn_ref, d_time_ref, + frame_nr, d_time_hint, ts_num, d_ts_ref); + + time_spec_t txtime_spec = time_spec_t(txtime.first, txtime.second); + txtime_spec -= d_delay_correction; + txtime_spec -= d_timing_advance; + + time_spec_t current_time_estimate = time_spec_t(d_time_hint.first, d_time_hint.second); + + if (txtime_spec <= current_time_estimate) { // Drop too late bursts + std::cout << "lB" << std::flush; + } else if (txtime_spec > current_time_estimate + MAX_EARLY_TIME_DIFF) { // Drop too early bursts + std::cout << "eB" << std::flush; //TODO: too early condition might happen when changing BTSes. + //Wrong fn_time is applied to new or old bursts in such situation. + //This solution is not perfect as MS might be blocked upto + //MAX_EARLY_TIME_DIFF seconds. + //Better solution would be to indentify fn_time and burst coming + //from given BTS (i.e. based on ARFCN) and dropping bursts for which + //the bts_id doesn't match with bts_id of fn_time. + } else { //process bursts that are in the right time-frame + pmt::pmt_t tags_dict = pmt::dict_add( + pmt::make_dict(), + pmt::intern("tx_time"), + pmt::make_tuple( + pmt::from_uint64(txtime_spec.get_full_secs()), + pmt::from_double(txtime_spec.get_frac_secs())) + ); + + tags_dict = pmt::dict_add(tags_dict, + pmt::intern("fn"), pmt::from_uint64(frame_nr)); + tags_dict = pmt::dict_add(tags_dict, + pmt::intern("ts"), pmt::from_uint64(ts_num)); + + // Send a message to the output + pmt::pmt_t msg_out = pmt::cons(tags_dict, pmt::cdr(msg_in)); + message_port_pub(pmt::mp("bursts_out"), msg_out); + } + } + } + + void txtime_setter_impl::set_fn_time_reference( + uint32_t fn, uint32_t ts, uint64_t time_secs, + double time_fracs) + { + d_fn_ref = fn; + d_ts_ref = ts; + d_time_ref = std::make_pair(time_secs, time_fracs); + set_time_hint(time_secs, time_fracs); + } + + void txtime_setter_impl::set_time_hint( + uint64_t time_hint_secs, double time_hint_fracs) + { + d_time_hint = std::make_pair(time_hint_secs, time_hint_fracs); + } + + void txtime_setter_impl::set_delay_correction(double delay_correction) + { + d_delay_correction = delay_correction; + } + + void txtime_setter_impl::set_timing_advance(double timing_advance) + { + d_timing_advance = timing_advance; + } + + } /* namespace gsm */ +} /* namespace gr */ |