diff options
Diffstat (limited to 'src/lib/gsm_receiver_cf.cc')
| -rw-r--r-- | src/lib/gsm_receiver_cf.cc | 178 |
1 files changed, 110 insertions, 68 deletions
diff --git a/src/lib/gsm_receiver_cf.cc b/src/lib/gsm_receiver_cf.cc index 5f730dc..045c639 100644 --- a/src/lib/gsm_receiver_cf.cc +++ b/src/lib/gsm_receiver_cf.cc @@ -29,10 +29,17 @@ #include <gr_math.h> #include <math.h> #include <Assert.h> +#include <list> +#include <boost/circular_buffer.hpp> #include <algorithm> -#define SAFETY_MARGIN 50 -#define BUFFER_SIZE (FCCH_HITS_NEEDED) +#define FCCH_BUFFER_SIZE (FCCH_HITS_NEEDED) +#define SYNC_SEARCH_RANGE 40 + +typedef std::list<float> list_float; +typedef std::vector<float> vector_float; + +typedef boost::circular_buffer<float> circular_buffer_float; gsm_receiver_cf_sptr gsm_make_receiver_cf(gr_feval_dd *tuner, int osr) @@ -58,10 +65,9 @@ gsm_receiver_cf::gsm_receiver_cf(gr_feval_dd *tuner, int osr) d_fcch_start_pos(0), d_freq_offset(0), d_state(first_fcch_search), - d_first(false) - // d_fcch_count(0), - // d_x_temp(0), - // d_x2_temp(0) + d_fcch_count(0), //!! + d_x_temp(0),//!! + d_x2_temp(0)//!! { gmsk_mapper(SYNC_BITS, d_sch_training_seq, N_SYNC_BITS); } @@ -75,7 +81,7 @@ 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 + SAFETY_MARGIN) * d_OSR; + ninput_items_required[0] = noutput_items * (TS_BITS + 2 * SAFETY_MARGIN) * d_OSR; } int @@ -87,11 +93,10 @@ gsm_receiver_cf::general_work(int noutput_items, const gr_complex *in = (const gr_complex *) input_items[0]; float *out = (float *) output_items[0]; int produced_out = 0; + float prev_freq_offset; switch (d_state) { - case first_fcch_search: - if (find_fcch_burst(in, ninput_items[0])) { set_frequency(d_freq_offset); produced_out = 0; @@ -100,11 +105,15 @@ gsm_receiver_cf::general_work(int noutput_items, produced_out = 0; d_state = first_fcch_search; } - break; case next_fcch_search: + prev_freq_offset = d_freq_offset; if (find_fcch_burst(in, ninput_items[0])) { + if (abs(d_freq_offset) > 100) { + float mean_freq_offset = (prev_freq_offset + d_freq_offset) / 2; +// set_frequency(d_freq_offset); + } produced_out = 0; d_state = sch_search; } else { @@ -115,12 +124,13 @@ gsm_receiver_cf::general_work(int noutput_items, case sch_search: if (find_sch_burst(in, ninput_items[0], out)) { - d_state = read_bcch; +// d_state = read_bcch; + d_state = next_fcch_search; } else { d_state = sch_search; } break; - + case read_bcch: break; } @@ -130,7 +140,7 @@ gsm_receiver_cf::general_work(int noutput_items, bool gsm_receiver_cf::find_fcch_burst(const gr_complex *in, const int nitems) { - circular_buffer_float phase_diff_buffer(BUFFER_SIZE * d_OSR); + circular_buffer_float phase_diff_buffer(FCCH_BUFFER_SIZE * d_OSR); float phase_diff = 0; gr_complex conjprod; @@ -145,6 +155,7 @@ bool gsm_receiver_cf::find_fcch_burst(const gr_complex *in, const int nitems) int sample_number = 0; bool end = false; bool result = false; +// float mean=0, phase_offset=0, freq_offset=0; circular_buffer_float::iterator buffer_iter; @@ -170,11 +181,10 @@ bool gsm_receiver_cf::find_fcch_burst(const gr_complex *in, const int nitems) case search: sample_number++; - if (sample_number > nitems - BUFFER_SIZE * d_OSR) { + if (sample_number > nitems - FCCH_BUFFER_SIZE * d_OSR) { to_consume = sample_number; fcch_search_state = search_fail; } else { - phase_diff = compute_phase_diff(in[sample_number], in[sample_number-1]); if (phase_diff > 0) { @@ -188,7 +198,6 @@ bool gsm_receiver_cf::find_fcch_burst(const gr_complex *in, const int nitems) break; case found_something: - if (phase_diff > 0) { hit_count++; } else { @@ -197,7 +206,7 @@ bool gsm_receiver_cf::find_fcch_burst(const gr_complex *in, const int nitems) if ((miss_count >= FCCH_MAX_MISSES * d_OSR) && (hit_count <= FCCH_HITS_NEEDED * d_OSR)) { fcch_search_state = init; - // DCOUT("hit_count: " << hit_count << " miss_count: " << miss_count << " d_counter: " << d_counter); + //DCOUT("hit_count: " << hit_count << " miss_count: " << miss_count << " d_counter: " << d_counter); continue; } else if ((miss_count >= FCCH_MAX_MISSES * d_OSR) && (hit_count > FCCH_HITS_NEEDED * d_OSR)) { fcch_search_state = fcch_found; @@ -214,7 +223,7 @@ bool gsm_receiver_cf::find_fcch_burst(const gr_complex *in, const int nitems) start_pos = sample_number - FCCH_HITS_NEEDED * d_OSR - FCCH_MAX_MISSES * d_OSR; d_best_sum = 0; - for (buffer_iter = (phase_diff_buffer.begin()); + for (buffer_iter = phase_diff_buffer.begin(); buffer_iter != (phase_diff_buffer.end()); buffer_iter++) { d_best_sum += *buffer_iter - (M_PI / 2) / d_OSR; @@ -231,7 +240,6 @@ bool gsm_receiver_cf::find_fcch_burst(const gr_complex *in, const int nitems) phase_diff = compute_phase_diff(in[sample_number], in[sample_number-1]); phase_diff_buffer.push_back(phase_diff); - fcch_search_state = found_something; break; @@ -239,9 +247,9 @@ bool gsm_receiver_cf::find_fcch_burst(const gr_complex *in, const int nitems) case fcch_found: DCOUT("znalezione fcch na pozycji" << d_counter + start_pos); to_consume = start_pos + FCCH_HITS_NEEDED * d_OSR + 1; - /* mean = d_best_sum / FCCH_HITS_NEEDED; - phase_offset = mean - (M_PI / 2); - freq_offset = phase_offset * 1625000.0 / (12.0 * M_PI);*/ +// mean = d_best_sum / FCCH_HITS_NEEDED; +// phase_offset = mean - (M_PI / 2); +// freq_offset = phase_offset * 1625000.0 / (12.0 * M_PI); d_fcch_start_pos = d_counter + start_pos; compute_freq_offset(); end = true; @@ -255,14 +263,7 @@ bool gsm_receiver_cf::find_fcch_burst(const gr_complex *in, const int nitems) } } - // DCOUT("hit_count: " << hit_count << " miss_count: " << miss_count << " d_counter: " << d_counter); - //! - for(int i = 0; i < to_consume; i++){ - //std::cout << "(" << real(in[i]) << "," << imag(in[i]) << ")\n"; - } - d_counter += to_consume; - consume_each(to_consume); return result; @@ -277,12 +278,13 @@ double gsm_receiver_cf::compute_freq_offset() freq_offset = phase_offset * 1625000.0 / (12.0 * M_PI); d_freq_offset -= freq_offset; -// d_x_temp += freq_offset; -// d_x2_temp += freq_offset * freq_offset; -// d_mean = d_x_temp / d_fcch_count; -// d_fcch_count++; - DCOUT("freq_offset: " << freq_offset << " d_best_sum: " << d_best_sum); -// DCOUT("wariancja: " << sqrt((d_x2_temp / d_fcch_count - d_mean * d_mean)) << " fcch_count:" << d_fcch_count << " d_mean: " << d_mean); + d_fcch_count++; + d_x_temp += freq_offset; + d_x2_temp += freq_offset * freq_offset; + d_mean = d_x_temp / d_fcch_count; + + DCOUT("freq_offset: " << freq_offset );//" d_best_sum: " << d_best_sum + DCOUT("wariancja: " << sqrt((d_x2_temp / d_fcch_count - d_mean * d_mean)) << " fcch_count:" << d_fcch_count << " d_mean: " << d_mean); return freq_offset; } @@ -299,19 +301,27 @@ bool gsm_receiver_cf::find_sch_burst(const gr_complex *in, const int nitems , fl bool end = false; bool result = false; int sample_nr_near_sch_start = d_fcch_start_pos + (FRAME_BITS - SAFETY_MARGIN) * d_OSR; + vector_complex correlation_buffer; + list_float power_buffer; + vector_float window_energy_buffer; + int strongest_window_nr; - enum states { start, reach_sch, find_sch_start, search_not_finished, sch_found } sch_search_state; - + sch_search_state = start; + //!!!! + int chan_imp_length = 4; + float energy = 0; + bool loop_end = false; + list_float::iterator iter; - while (!end) { switch (sch_search_state) { + case start: - if(d_counter < sample_nr_near_sch_start){ + if (d_counter < sample_nr_near_sch_start) { sch_search_state = reach_sch; } else { sch_search_state = find_sch_start; @@ -319,48 +329,67 @@ bool gsm_receiver_cf::find_sch_burst(const gr_complex *in, const int nitems , fl break; case reach_sch: - - if(d_counter + nitems >= sample_nr_near_sch_start){ + if (d_counter + nitems >= sample_nr_near_sch_start) { to_consume = sample_nr_near_sch_start - d_counter; - DCOUT("reach_sch consumes: " << to_consume << "bits"); } else { to_consume = nitems; } - - - sch_search_state = search_not_finished; break; case find_sch_start: - DCOUT("find_sch_start nitems" << nitems); -// if ((sch_start >= d_counter) && (sch_start <= d_counter + nitems)) { -// for (int i = 0; i < ninput_items[0] - N_SYNC_BITS; i++) { -// gr_complex result; -// d_counter++; -// result = correlation(&d_sch_training_seq[5], in + i, N_SYNC_BITS - 10); -// -// if (abs(result) > 60000) { -// DCOUT("znaleziono środek sch na pozycji: " << d_counter); -// } -// -// // std::cout << "(" << real(in[i]) << "," << imag(in[i]) << ")\n"; -// // std::cout << "(" << real(result) << "," << imag(result) << ")\n"; -// -// int ninput = N_SYNC_BITS - 10; -// const gr_complex * input_signal = in + i; -// gr_complex * sequence = &d_sch_training_seq[5]; -// } -// } - to_consume = nitems; +// DCOUT("find_sch_start d_counter" << d_counter); + for (int ii = SYNC_POS * d_OSR; ii < (SYNC_POS + SYNC_SEARCH_RANGE)*d_OSR; ii++) { + to_consume++; + gr_complex correlation = correlate_sequence(&d_sch_training_seq[5], &in[ii], N_SYNC_BITS - 10); + correlation_buffer.push_back(correlation); // tylko do znalezienia odp imp kanału + power_buffer.push_back(pow(abs(correlation), 2)); + if (abs(correlation) > 30000) { + DCOUT("znaleziono środek sch na pozycji: " << ii - SYNC_POS * d_OSR); + } + } + + //compute window energies + iter = power_buffer.begin(); + while (iter != power_buffer.end()) { + list_float::iterator iter_ii = iter; + energy = 0; + + for (int ii = 0; ii < chan_imp_length; ii++, iter_ii++) { + if (iter_ii == power_buffer.end()) { + loop_end = true; + break; + } + energy += (*iter_ii); + } + + if (loop_end) { + break; + } + iter++; +// std::cout << energy << "\n"; + window_energy_buffer.push_back(energy); + } + + strongest_window_nr = max_element(window_energy_buffer.begin(), window_energy_buffer.end()) - window_energy_buffer.begin(); + d_channel_imp_resp.clear(); + for (int ii = 0; ii < chan_imp_length; ii++) { + gr_complex correlation = correlation_buffer[strongest_window_nr + (ii * d_OSR)]; + d_channel_imp_resp.push_back(correlation); + } + + DCOUT("strongest_window_nr: " << strongest_window_nr); + sch_search_state = sch_found; break; case search_not_finished: + result = false; end = true; break; case sch_found: + result = true; end = true; break; } @@ -393,12 +422,12 @@ void gsm_receiver_cf::gmsk_mapper(const int * input, gr_complex * output, int ni } } -gr_complex gsm_receiver_cf::correlation(const gr_complex * sequence, const gr_complex * input_signal, int ninput) +gr_complex gsm_receiver_cf::correlate_sequence(const gr_complex * sequence, const gr_complex * input_signal, int length) { gr_complex result(0.0, 0.0); int sample_number = 0; - for (int ii = 0; ii < ninput; ii++) { + for (int ii = 0; ii < length; ii++) { sample_number = (ii * d_OSR) ; result += sequence[ii] * conj(input_signal[sample_number]); } @@ -406,6 +435,19 @@ gr_complex gsm_receiver_cf::correlation(const gr_complex * sequence, const gr_co return result; } +// gr_complex gsm_receiver_cf::compute_energy(const gr_complex * input_signal, int length) +// { +// float result = 0; +// int sample_number = 0; +// +// for (int ii = 0; ii < length; ii++) { +// result += input_signal[(ii * d_OSR)]; +// } +// +// return result; +// } + + // gr_complex gsm_receiver_cf::calc_energy(int window_len){ // // } @@ -413,4 +455,4 @@ inline float gsm_receiver_cf::compute_phase_diff(gr_complex val1, gr_complex val { gr_complex conjprod = val1 * conj(val2); return gr_fast_atan2f(imag(conjprod), real(conjprod)); -}
\ No newline at end of file +} |