/* -*- c++ -*- */ /* * @file * @author (C) 2018 by Andrew Artyushok * @author (C) 2018 by Vasil Velichkov * @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 #include "tch_h_chans_demapper_impl.h" #include #include #define BURST_SIZE 148 namespace gr { namespace gsm { tch_h_chans_demapper::sptr tch_h_chans_demapper::make(unsigned int timeslot_nr, unsigned int tch_h_channel) { return gnuradio::get_initial_sptr (new tch_h_chans_demapper_impl(timeslot_nr, tch_h_channel)); } /* * The private constructor * */ tch_h_chans_demapper_impl::tch_h_chans_demapper_impl(unsigned int timeslot_nr, unsigned int tch_h_channel) : gr::block("tch_h_chans_demapper", gr::io_signature::make(0, 0, 0), gr::io_signature::make(0, 0, 0)), d_timeslot(timeslot_nr), d_tch_h_channel(tch_h_channel) { //std::cout << "d_tch_type is " << d_tch_type << ", tch_h_channel is " << tch_h_channel << std::endl; message_port_register_in(pmt::mp("bursts")); set_msg_handler(pmt::mp("bursts"), boost::bind(&tch_h_chans_demapper_impl::filter_tch_chans, this, boost::placeholders::_1)); message_port_register_out(pmt::mp("tch_bursts")); message_port_register_out(pmt::mp("acch_bursts")); } /* * Our virtual destructor. */ tch_h_chans_demapper_impl::~tch_h_chans_demapper_impl() { } void tch_h_chans_demapper_impl::filter_tch_chans(pmt::pmt_t msg) { pmt::pmt_t header_plus_burst = pmt::cdr(msg); gsmtap_hdr * header = (gsmtap_hdr *)pmt::blob_data(header_plus_burst); if(header->timeslot != d_timeslot) { return; } uint32_t frame_nr = be32toh(header->frame_number); uint32_t fn_mod26 = frame_nr % 26; uint32_t fn_mod13 = frame_nr % 13; int8_t* burst_bits = (int8_t *)(pmt::blob_data(header_plus_burst)) + sizeof(gsmtap_hdr); int8_t new_msg[sizeof(gsmtap_hdr)+BURST_SIZE]; gsmtap_hdr * new_hdr = (gsmtap_hdr*)new_msg; memcpy(new_msg, header, sizeof(gsmtap_hdr)+BURST_SIZE); new_hdr->sub_type = (fn_mod13 == 12 ? GSMTAP_CHANNEL_ACCH : 0) | GSMTAP_CHANNEL_TCH_H; new_hdr->sub_slot = d_tch_h_channel; pmt::pmt_t msg_binary_blob = pmt::make_blob(new_msg,sizeof(gsmtap_hdr)+BURST_SIZE); pmt::pmt_t msg_out = pmt::cons(pmt::PMT_NIL, msg_binary_blob); //distinguishing uplink and downlink bursts bool uplink_burst = (be16toh(header->arfcn) & 0x4000) ? true : false; if(uplink_burst) { sacch_tch_demapper(fn_mod13, fn_mod26, frame_nr, d_bursts_sacch_ul, d_frame_numbers_sacch_ul, d_bursts_ul, d_frame_numbers_ul, msg_out); } else { sacch_tch_demapper(fn_mod13, fn_mod26, frame_nr, d_bursts_sacch_dl, d_frame_numbers_sacch_dl, d_bursts_dl, d_frame_numbers_dl, msg_out); } } void tch_h_chans_demapper_impl::sacch_tch_demapper(uint32_t fn_mod13, u_int32_t fn_mod26, uint32_t frame_nr, pmt::pmt_t *d_bursts_sacch, uint32_t *d_frame_numbers_sacch, pmt::pmt_t d_bursts[3][8], uint32_t d_frame_numbers[3][8], pmt::pmt_t msg_out) { bool frames_are_consecutive = true; if (fn_mod13 == 12) { // position of SACCH burst based on timeslot // see specification gsm 05.02 uint32_t index; bool is_sacch = false; if (d_tch_h_channel == 0 && fn_mod26 == 12) { index = (((frame_nr - 12) / 26) - (d_timeslot / 2)) % 4; is_sacch = true; } else if (d_tch_h_channel == 1 && fn_mod26 == 25) { index = (((frame_nr - 25) / 26) - (d_timeslot / 2)) % 4; is_sacch = true; } if (is_sacch) { d_bursts_sacch[index] = msg_out; d_frame_numbers_sacch[index] = frame_nr; if (index == 3) { //check for a situation where some bursts were lost //in this situation frame numbers won't be consecutive frames_are_consecutive = true; for(int jj=1; jj<4; jj++) { if((d_frame_numbers_sacch[jj]-d_frame_numbers_sacch[jj-1]) != 26) { frames_are_consecutive = false; } } if(frames_are_consecutive) { //send bursts to the output for(int jj=0; jj<4; jj++) { message_port_pub(pmt::mp("acch_bursts"), d_bursts_sacch[jj]); } } } } } else { bool our_sub=false; // So, here I change the fn_mod13, with this changes I can // process both subslot (d_tch_h_channel) with the same code. // // Theory about this on github // // Example: // // For subslot=0 our burst is 0,2,4,6 etc // For subslot=1 it 1,3,5 etc // But if we change it with this code, // both will be 0,1,2,3,4 etc // And we can proced two subslot like one. if(fn_mod13%2==d_tch_h_channel) { if(d_tch_h_channel==0) { fn_mod13=fn_mod13/2; }else{ fn_mod13-=1; fn_mod13=fn_mod13/2; } // We work only with our subslot our_sub=true; } if(our_sub) { if (fn_mod13 <= 1) { // add to b1 and b3 d_bursts[0][fn_mod13] = msg_out; d_bursts[2][fn_mod13+2] = msg_out; d_frame_numbers[0][fn_mod13] = frame_nr; d_frame_numbers[2][fn_mod13+2] = frame_nr; } else if (fn_mod13 >=2 && fn_mod13 <=3) { // add to b1 and b2 d_bursts[0][fn_mod13] = msg_out; d_bursts[1][fn_mod13-2] = msg_out; d_frame_numbers[0][fn_mod13] = frame_nr; d_frame_numbers[1][fn_mod13-2] = frame_nr; //d_frame_numbers[1][fn_mod13 - 4] = frame_nr; } else if (fn_mod13 >=4 && fn_mod13 <=5) { // add to b1 and b2 d_bursts[1][fn_mod13-2] = msg_out; d_bursts[2][fn_mod13-4] = msg_out; d_frame_numbers[1][fn_mod13-2] = frame_nr; d_frame_numbers[2][fn_mod13-4] = frame_nr; //d_frame_numbers[1][fn_mod13 - 4] = frame_nr; } // send burst 1 or burst 2 to output //if ( fn_mod26 == 2 || fn_mod26 == 5 || fn_mod26 == 9) if(fn_mod13 == 1 || fn_mod13 == 3|| fn_mod13 == 5) { int tch_burst_nr = 0; if(fn_mod13==5) { tch_burst_nr = 1; } if(fn_mod13==1) { tch_burst_nr = 2; } //check for a situation where some bursts were lost //in this situation frame numbers won't be consecutive frames_are_consecutive = true; // std::cout<<"br="<