diff options
Diffstat (limited to 'src/lib/gsm_receiver_cf.cc')
| -rw-r--r-- | src/lib/gsm_receiver_cf.cc | 53 |
1 files changed, 33 insertions, 20 deletions
diff --git a/src/lib/gsm_receiver_cf.cc b/src/lib/gsm_receiver_cf.cc index c47e111..c1280f4 100644 --- a/src/lib/gsm_receiver_cf.cc +++ b/src/lib/gsm_receiver_cf.cc @@ -75,10 +75,10 @@ gsm_receiver_cf::gsm_receiver_cf(gr_feval_dd *tuner, int osr) d_burst_nr(osr) { int i; - gmsk_mapper(SYNC_BITS, N_SYNC_BITS, d_sch_training_seq, gr_complex(0.0,-1.0)); + gmsk_mapper(SYNC_BITS, N_SYNC_BITS, d_sch_training_seq, gr_complex(0.0, -1.0)); for (i = 0; i < TRAIN_SEQ_NUM; i++) { - gmsk_mapper(train_seq[i], N_TRAIN_BITS, d_norm_training_seq[i], gr_complex(1.0,0.0)); + gmsk_mapper(train_seq[i], N_TRAIN_BITS, d_norm_training_seq[i], gr_complex(1.0, 0.0)); } } @@ -91,7 +91,7 @@ gsm_receiver_cf::~gsm_receiver_cf() void gsm_receiver_cf::forecast(int noutput_items, gr_vector_int &ninput_items_required) { - ninput_items_required[0] = noutput_items * (TS_BITS + 2 * SAFETY_MARGIN) * d_OSR; + ninput_items_required[0] = noutput_items * floor((TS_BITS + 2 * GUARD_PERIOD) * d_OSR); } int @@ -207,13 +207,11 @@ gsm_receiver_cf::general_work(int noutput_items, case normal_burst: burst_start = get_norm_chan_imp_resp(in, chan_imp_resp, TRAIN_SEARCH_RANGE); detect_burst(in, &d_channel_imp_resp[0], burst_start, output_binary); -// printf("burst = [ "); -// -// for (int i = 0; i < BURST_SIZE ; i++) { -// printf(" %d", output_binary[i]); -// } -// printf("];\n"); - + printf("burst = [ "); + for (int i = 0; i < BURST_SIZE ; i++) { + printf(" %d", output_binary[i]); + } + printf("];\n"); break; case rach_burst: @@ -596,12 +594,13 @@ int gsm_receiver_cf::get_norm_chan_imp_resp(const gr_complex *in, gr_complex * c int chan_imp_resp_center; float max_correlation = 0; float energy = 0; - - int search_start_pos = floor((TRAIN_POS + GUARD_PERIOD) * d_OSR); - int search_stop_pos = search_start_pos + search_range * d_OSR; + + int search_center = (int)((TRAIN_POS + GUARD_PERIOD) * d_OSR); + int search_start_pos = search_center+1; + int search_stop_pos = search_center + d_chan_imp_length * d_OSR + 2*d_OSR; for (int ii = search_start_pos; ii < search_stop_pos; ii++) { - gr_complex correlation = correlate_sequence(&d_norm_training_seq[d_bcc][5], &in[ii], N_TRAIN_BITS - 10); + gr_complex correlation = correlate_sequence(&d_norm_training_seq[d_bcc][TRAIN_BEGINNING], &in[ii], N_TRAIN_BITS - 10); correlation_buffer.push_back(correlation); power_buffer.push_back(pow(abs(correlation), 2)); @@ -615,24 +614,27 @@ int gsm_receiver_cf::get_norm_chan_imp_resp(const gr_complex *in, gr_complex * c energy = 0; for (int ii = 0; ii < (d_chan_imp_length)*d_OSR; ii++, iter_ii++) { +// for (int ii = 0; ii < (d_chan_imp_length); ii++) { if (iter_ii == power_buffer.end()) { loop_end = true; break; } energy += (*iter_ii); +// iter_ii = iter_ii + d_OSR; } if (loop_end) { break; } iter++; +// std::cout << energy << "\n"; + window_energy_buffer.push_back(energy); } - - +// std::cout << window_energy_buffer.size() << "\n"; strongest_window_nr = max_element(window_energy_buffer.begin(), window_energy_buffer.end()) - window_energy_buffer.begin(); d_channel_imp_resp.clear(); - strongest_window_nr = 36; +// strongest_window_nr = 3; max_correlation = 0; for (int ii = 0; ii < (d_chan_imp_length)*d_OSR; ii++) { @@ -644,9 +646,20 @@ int gsm_receiver_cf::get_norm_chan_imp_resp(const gr_complex *in, gr_complex * c d_channel_imp_resp.push_back(correlation); chan_imp_resp[ii] = correlation; } +//WE WANT TO USE THE FIRST SAMPLE OF THE IMPULSERESPONSE, AND THE +// CORRESPONDING SAMPLES OF THE RECEIVED SIGNAL. +// THE VARIABLE sync_w SHOULD CONTAIN THE BEGINNING OF THE USED PART OF +// TRAINING SEQUENCE, WHICH IS 3+57+1+6=67 BITS INTO THE BURST. THAT IS +// WE HAVE THAT sync_T16 EQUALS FIRST SAMPLE IN BIT NUMBER 67. + + + burst_start = search_start_pos + chan_imp_resp_center + strongest_window_nr - 66 * d_OSR - 2 * d_OSR + 2; +// COMPENSATING FOR THE 2 Tb DELAY INTRODUCED IN THE GMSK MODULATOR. +// EACH BIT IS STRECHED OVER A PERIOD OF 3 Tb WITH ITS MAXIMUM VALUE +// IN THE LAST BIT PERIOD. HENCE, burst_start IS 2 * OSR +//compute burst start + std::cout << " burst_start: " << (float)burst_start/(float)d_OSR<< " center: " << ((float)(search_start_pos + strongest_window_nr + chan_imp_resp_center))/d_OSR << " stronegest window nr: " << strongest_window_nr << "\n"; - std::cout << "center: " << strongest_window_nr + chan_imp_resp_center << " stronegest window nr: " << strongest_window_nr << "\n"; - - burst_start = search_start_pos + strongest_window_nr + chan_imp_resp_center - 66 * d_OSR - 2 * d_OSR + 2; return burst_start; + } |