| /* -*- c++ -*- */ |
| /* |
| * @file |
| * @author Piotr Krysik <ptrkrysik@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/endian.h> |
| #include <grgsm/gsmtap.h> |
| #include "get_bcch_or_ccch_bursts_impl.h" |
| |
| namespace gr { |
| namespace gsm { |
| |
| get_bcch_or_ccch_bursts::sptr |
| get_bcch_or_ccch_bursts::make(unsigned int fn51_start) |
| { |
| return gnuradio::get_initial_sptr |
| (new get_bcch_or_ccch_bursts_impl(fn51_start)); |
| } |
| |
| /* |
| * The private constructor |
| */ |
| get_bcch_or_ccch_bursts_impl::get_bcch_or_ccch_bursts_impl(unsigned int fn51_start) |
| : gr::block("get_bcch_or_ccch_bursts", |
| gr::io_signature::make(0, 0, 0), |
| gr::io_signature::make(0, 0, 0)), |
| d_fn51_start(fn51_start) |
| { |
| message_port_register_in(pmt::mp("bursts")); |
| set_msg_handler(pmt::mp("bursts"), boost::bind(&get_bcch_or_ccch_bursts_impl::filter_ccch, this, _1)); |
| message_port_register_out(pmt::mp("bursts")); |
| } |
| |
| /* |
| * Our virtual destructor. |
| */ |
| get_bcch_or_ccch_bursts_impl::~get_bcch_or_ccch_bursts_impl() |
| { |
| } |
| |
| void get_bcch_or_ccch_bursts_impl::filter_ccch(pmt::pmt_t msg) |
| { |
| pmt::pmt_t header_plus_burst = pmt::cdr(msg); |
| gsmtap_hdr * header = (gsmtap_hdr *)pmt::blob_data(header_plus_burst); |
| uint32_t frame_nr = be32toh(header->frame_number); |
| |
| uint32_t fn_mod51 = frame_nr % 51; |
| int fn51_stop = d_fn51_start+3; |
| |
| if(header->timeslot==0){ |
| if(fn_mod51>=d_fn51_start && fn_mod51<=fn51_stop){ |
| uint32_t ii = fn_mod51-d_fn51_start; |
| d_frame_numbers[ii]=frame_nr; |
| d_bursts[ii] = msg; |
| } |
| |
| if(fn_mod51==fn51_stop){ |
| //check for a situation where some BCCH bursts were lost |
| //in this situation frame numbers won't be consecutive |
| bool frames_are_consecutive = true; |
| for(int jj=1; jj<4; jj++) |
| { |
| if((d_frame_numbers[jj]-d_frame_numbers[jj-1])!=1){ |
| 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("bursts"), d_bursts[jj]); |
| } |
| } |
| } |
| } |
| } |
| } /* namespace gsm */ |
| } /* namespace gr */ |
| |