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Diffstat (limited to 'lib/demapping/tch_h_chans_demapper_impl.cc')
| -rw-r--r-- | lib/demapping/tch_h_chans_demapper_impl.cc | 278 |
1 files changed, 278 insertions, 0 deletions
diff --git a/lib/demapping/tch_h_chans_demapper_impl.cc b/lib/demapping/tch_h_chans_demapper_impl.cc new file mode 100644 index 0000000..2c3dc79 --- /dev/null +++ b/lib/demapping/tch_h_chans_demapper_impl.cc @@ -0,0 +1,278 @@ +/* -*- c++ -*- */ +/* + * @file + * @author (C) 2018 by Andrew Artyushok <loony.developer@gmail.com> + * @author (C) 2018 by Vasil Velichkov <vvvelichkov@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 "tch_h_chans_demapper_impl.h" +#include <grgsm/endian.h> +#include <grgsm/gsmtap.h> + +#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, _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; + + 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="<<tch_burst_nr<<" Array: "; + // std::cout<<d_frame_numbers[tch_burst_nr][0]<<" "; + bool one_tree=true; + for(int jj=1; jj<4; jj++) + { + + if (((d_frame_numbers[tch_burst_nr][jj] - d_frame_numbers[tch_burst_nr][jj-1]) != 2) && frames_are_consecutive) + { + frames_are_consecutive = false; + + if (tch_burst_nr == 2 && jj == 2 + && d_frame_numbers[tch_burst_nr][jj] - d_frame_numbers[tch_burst_nr][jj - 1] == 3) + { + // std::cout<<" YEAH "; + frames_are_consecutive = true; + } + + } + //} + } + // std::cout<<std::endl; + + if(frames_are_consecutive) + { + + for(int jj=0; jj<4; jj++) + { + + message_port_pub(pmt::mp("tch_bursts"), d_bursts[tch_burst_nr][jj]); + } + + // useless + // d_bursts_stolen[tch_burst_nr] = false; + } + } + } + +} +} +} /* namespace gsm */ +} /* namespace gr */ |