diff options
| -rw-r--r-- | src/lib/Assert.h | 2 | ||||
| -rw-r--r-- | src/lib/gsm_constants.h | 2 | ||||
| -rw-r--r-- | src/lib/gsm_receiver_cf.cc | 219 | ||||
| -rw-r--r-- | src/lib/gsm_receiver_cf.h | 38 | ||||
| -rwxr-xr-x | src/python/gsm_findfcch.py | 6 |
5 files changed, 198 insertions, 69 deletions
diff --git a/src/lib/Assert.h b/src/lib/Assert.h index 6c04f18..acfb3f7 100644 --- a/src/lib/Assert.h +++ b/src/lib/Assert.h @@ -26,6 +26,8 @@ #include "stdio.h" #include <iostream> +#define NDEBUG + /**@name Macros for standard messages. */ //@{ #define COUT(text) { std::cout << text << std::endl; } diff --git a/src/lib/gsm_constants.h b/src/lib/gsm_constants.h index 01dfb22..62dc86b 100644 --- a/src/lib/gsm_constants.h +++ b/src/lib/gsm_constants.h @@ -21,7 +21,7 @@ #define TRAIN_POS 58 #define FCCH_HITS_NEEDED (USEFUL_BITS - 4) -#define FCCH_MAX_MISSES 2 +#define FCCH_MAX_MISSES 1 static const int SYNC_BITS[] = { 1, 0, 1, 1, 1, 0, 0, 1, 0, 1, 1, 0, 0, 0, 1, 0, diff --git a/src/lib/gsm_receiver_cf.cc b/src/lib/gsm_receiver_cf.cc index 4f43f2b..3b0e426 100644 --- a/src/lib/gsm_receiver_cf.cc +++ b/src/lib/gsm_receiver_cf.cc @@ -28,7 +28,6 @@ #include <gr_io_signature.h> #include <gr_math.h> #include <math.h> -#include <gsm_constants.h> #include <Assert.h> #include <algorithm> @@ -53,16 +52,18 @@ gsm_receiver_cf::gsm_receiver_cf(gr_feval_dd *tuner, int osr) : gr_block("gsm_receiver", gr_make_io_signature(MIN_IN, MAX_IN, sizeof(gr_complex)), gr_make_io_signature(MIN_OUT, MAX_OUT, 142 * sizeof(float))), - d_osr(osr), + d_OSR(osr), d_tuner(tuner), d_prev_freq_offset(0), - d_phase_diff_buffer(BUFFER_SIZE), + d_phase_diff_buffer(BUFFER_SIZE * osr), d_counter(0), d_x_temp(0), d_x2_temp(0), d_fcch_count(0), + d_fcch_start_pos(0), d_state(fcch_search) { + gmsk_mapper(SYNC_BITS, d_sch_training_seq, N_SYNC_BITS); } /* @@ -85,7 +86,7 @@ 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; + int produced_out = 0; switch (d_state) { @@ -93,7 +94,7 @@ gsm_receiver_cf::general_work(int noutput_items, if (find_fcch_burst(in, ninput_items[0])) { produced_out = 1; - d_state = fcch_search; + d_state = sch_search; } else { produced_out = 0; d_state = fcch_search; @@ -102,6 +103,46 @@ gsm_receiver_cf::general_work(int noutput_items, break; case sch_search: + + if (find_sch_burst(in, ninput_items[0], out)) { + + d_state = sch_search; + } else { + for (int i = 0; i < ninput_items[0] - N_SYNC_BITS; i++) { + gr_complex result; + d_counter++; + int ninput = N_SYNC_BITS - 10; + const gr_complex * input_signal = in + i; + gr_complex * sequence = &d_sch_training_seq[5]; + result = correlation(&d_sch_training_seq[5], in + i, N_SYNC_BITS-10); + if (abs(result) > 60000) { + std::cout << "Max val: " << abs(result) << " position: " << d_counter - d_fcch_start_pos << std::endl; +// +// for (int j = 1; j <= 54; j++) { +// std::cout << sequence[j-1] << " * " << conj(input_signal[(j * d_OSR)]) << std::endl; +// } +// +// gr_complex result2(0, 0); +// +// for (int j = 1; j <= 54; j++) { +// result2 += sequence[j-1] * conj(input_signal[(j * d_OSR)]); +// } +// +// std::cout << "Spr: " << abs(result2) << std::endl; +// +// std::cout << std::endl; + } + + +// std::cout << "(" << real(in[i]) << "," << imag(in[i]) << ")\n"; +// std::cout << "(" << real(result) << "," << imag(result) << ")\n"; + } + + consume_each(ninput_items[0]); + + d_state = sch_search; + } + break; } @@ -116,14 +157,15 @@ bool gsm_receiver_cf::find_fcch_burst(const gr_complex *in, const int nitems) { float phase_diff = 0; gr_complex conjprod; - int hit_count, miss_count, start_pos; + int hit_count = 0; + int miss_count = 0; + int start_pos; float min_phase_diff, max_phase_diff, lowest_max_min_diff; - float sum, best_sum; int to_consume = 0; - int i = 0; + int sample_number = 0; bool end = false; - bool result; + bool result = false; circular_buffer_float::iterator buffer_iter; @@ -133,7 +175,7 @@ bool gsm_receiver_cf::find_fcch_burst(const gr_complex *in, const int nitems) fcch_search_state = init; - while ((!end) && (i < nitems)) { + while (!end) { switch (fcch_search_state) { case init: @@ -147,23 +189,22 @@ bool gsm_receiver_cf::find_fcch_burst(const gr_complex *in, const int nitems) break; case search: - i++; + sample_number++; - if (i > nitems - BUFFER_SIZE) { - to_consume = i; + if (sample_number > nitems - BUFFER_SIZE * d_OSR) { + to_consume = sample_number; fcch_search_state = search_fail; - } - - conjprod = in[i] * conj(in[i-1]); + } else { - phase_diff = gr_fast_atan2f(imag(conjprod), real(conjprod)); + conjprod = in[sample_number] * conj(in[sample_number-1]); + phase_diff = gr_fast_atan2f(imag(conjprod), real(conjprod)); - if (phase_diff > 0) { -// start_pos = i - 1; - to_consume = i; - fcch_search_state = found_something; - } else { - fcch_search_state = search; + if (phase_diff > 0) { + to_consume = sample_number; + fcch_search_state = found_something; + } else { + fcch_search_state = search; + } } break; @@ -176,42 +217,42 @@ bool gsm_receiver_cf::find_fcch_burst(const gr_complex *in, const int nitems) miss_count++; } - //DCOUT("d_phase_diff_buffer.size(): " << d_phase_diff_buffer.size() << " hit_count: " << hit_count); - - if ((miss_count >= FCCH_MAX_MISSES) && (hit_count <= FCCH_HITS_NEEDED)) { + 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); continue; - } else if ((miss_count >= FCCH_MAX_MISSES) && (hit_count > FCCH_HITS_NEEDED)) { + } else if ((miss_count >= FCCH_MAX_MISSES * d_OSR) && (hit_count > FCCH_HITS_NEEDED * d_OSR)) { fcch_search_state = fcch_found; continue; - } else if ((miss_count < FCCH_MAX_MISSES) && (hit_count > FCCH_HITS_NEEDED)) { + } else if ((miss_count < FCCH_MAX_MISSES * d_OSR) && (hit_count > FCCH_HITS_NEEDED * d_OSR)) { //find difference between minimal and maximal element in the buffer //for FCCH this value should be low //this part is searching for a region where this value is lowest min_phase_diff = *(min_element(d_phase_diff_buffer.begin(), d_phase_diff_buffer.end())); max_phase_diff = *(max_element(d_phase_diff_buffer.begin(), d_phase_diff_buffer.end())); - - if(lowest_max_min_diff > max_phase_diff - min_phase_diff){ + + if (lowest_max_min_diff > max_phase_diff - min_phase_diff) { lowest_max_min_diff = max_phase_diff - min_phase_diff; - start_pos = i - FCCH_HITS_NEEDED; + start_pos = sample_number - FCCH_HITS_NEEDED * d_OSR - FCCH_MAX_MISSES * d_OSR; d_best_sum = 0; + for (buffer_iter = (d_phase_diff_buffer.begin()); buffer_iter != (d_phase_diff_buffer.end()); buffer_iter++) { - d_best_sum += *buffer_iter; + d_best_sum += *buffer_iter - (M_PI / 2) / d_OSR; } - DCOUT(d_best_sum); } } - i++; + sample_number++; - if (i >= nitems) { + if (sample_number >= nitems) { fcch_search_state = search_fail; continue; } - conjprod = in[i] * conj(in[i-1]); + conjprod = in[sample_number] * conj(in[sample_number-1]); + phase_diff = gr_fast_atan2f(imag(conjprod), real(conjprod)); d_phase_diff_buffer.push_back(phase_diff); @@ -221,10 +262,11 @@ 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 + 1; + 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);*/ + d_fcch_start_pos = d_counter + start_pos; compute_freq_offset(); end = true; result = true; @@ -237,14 +279,15 @@ 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); + d_counter += to_consume; + consume_each(to_consume); return result; } -bool find_sch_burst( const gr_complex *in, const int nitems , gr_complex *out); - double gsm_receiver_cf::compute_freq_offset() { @@ -252,19 +295,17 @@ double gsm_receiver_cf::compute_freq_offset() DCOUT(" d_phase_diff_buffer.size(): " << d_phase_diff_buffer.size()); - mean = d_best_sum / FCCH_HITS_NEEDED; - phase_offset = mean - (M_PI / 2); + //mean = d_best_sum / FCCH_HITS_NEEDED; + phase_offset = d_best_sum / FCCH_HITS_NEEDED; + //phase_offset = mean - ; freq_offset = phase_offset * 1625000.0 / (12.0 * M_PI); - DCOUT("freq_offset: " << freq_offset); + DCOUT("freq_offset: " << freq_offset << " d_best_sum: " << d_best_sum); d_fcch_count++; d_x_temp += freq_offset; d_x2_temp += freq_offset * freq_offset; d_mean = d_x_temp / d_fcch_count; - //d_mean = 0.9 * freq_offset + 0.1 * d_mean; - - - //d_tuner->calleval(freq_offset); + set_frequency(freq_offset); d_prev_freq_offset -= freq_offset; DCOUT("wariancja: " << sqrt((d_x2_temp / d_fcch_count - d_mean * d_mean)) << " fcch_count:" << d_fcch_count << " d_mean: " << d_mean); @@ -272,12 +313,92 @@ double gsm_receiver_cf::compute_freq_offset() return freq_offset; } -void gsm_receiver_cf::set_frequency() +void gsm_receiver_cf::set_frequency(double freq_offset) { + d_tuner->calleval(freq_offset); +} + +bool gsm_receiver_cf::find_sch_burst(const gr_complex *in, const int nitems , float *out) +{ + int sample_number = 0; + int to_consume = 0; + bool end = false; + bool result = false; + int sch_start = d_fcch_start_pos + FRAME_BITS * d_OSR; + + enum states { + init, search, sch_found, search_fail + } sch_search_state; + + while (!end) { + switch (sch_search_state) { + case init: + sch_search_state = search_fail; + break; + + case search: + + if ((sch_start >= d_counter) && (sch_start <= d_counter + nitems)) { + DCOUT("sch_start-d_counter: " << sch_start - d_counter); + /* for (int i = 0; i < nitems - N_SYNC_BITS; i++) { + gr_complex result = correlation(&d_sch_training_seq[5], in + i, N_SYNC_BITS-10); + //std::cout << "(" << real(in[i]) << "," << imag(in[i]) << ")\n"; + std::cout << "(" << real(result) << "," << imag(result) << ")\n"; + } + std::cout << std::endl; + */ + } + + to_consume = nitems - N_SYNC_BITS; + + sch_search_state = search_fail; + break; + + case sch_found: + end = true; + break; + + case search_fail: + end = true; + break; + } + } + + d_counter += to_consume; + +// consume_each(to_consume); + + return result; } -bool gsm_receiver_cf::find_sch_burst( const gr_complex *in, const int nitems , gr_complex *out) +void gsm_receiver_cf::gmsk_mapper(const int * input, gr_complex * output, int ninput) { - + gr_complex j = gr_complex(0.0, 1.0); + + int current_symbol; + int encoded_symbol; + int previous_symbol = 2 * input[0] - 1; + output[0] = gr_complex(1.0, 0.0); + + for (int i = 1; i < ninput; i++) { + //change bits representation to NRZ + current_symbol = 2 * input[i] - 1; + //differentially encode + encoded_symbol = current_symbol * previous_symbol; + //and do gmsk mapping + output[i] = j * gr_complex(encoded_symbol, 0.0) * output[i-1]; + previous_symbol = current_symbol; + } +} + +gr_complex gsm_receiver_cf::correlation(const gr_complex * sequence, const gr_complex * input_signal, int ninput) +{ + gr_complex result(0.0, 0.0); + + for (int ii = 1; (ii * d_OSR) <= ninput; ii++) { + result += sequence[ii-1] * conj(input_signal[(ii * d_OSR)]); + } + + return result; } diff --git a/src/lib/gsm_receiver_cf.h b/src/lib/gsm_receiver_cf.h index 2012325..0e287c5 100644 --- a/src/lib/gsm_receiver_cf.h +++ b/src/lib/gsm_receiver_cf.h @@ -26,6 +26,8 @@ #include <gr_complex.h> #include <gr_feval.h> #include <boost/circular_buffer.hpp> +#include <gsm_constants.h> + class gsm_receiver_cf; @@ -51,7 +53,7 @@ typedef boost::circular_buffer<float> circular_buffer_float; * constructor is private. howto_make_square_ff is the public * interface for creating new instances. */ -gsm_receiver_cf_sptr gsm_make_receiver_cf( gr_feval_dd *tuner, int osr ); +gsm_receiver_cf_sptr gsm_make_receiver_cf(gr_feval_dd *tuner, int osr); /*! * \brief Receives fcch @@ -64,34 +66,38 @@ class gsm_receiver_cf : public gr_block private: gr_feval_dd *d_tuner; - const int d_osr; + const int d_OSR; int d_counter; + int d_fcch_start_pos; float d_prev_freq_offset; circular_buffer_float d_phase_diff_buffer; double d_x_temp, d_x2_temp, d_mean; int d_fcch_count; double d_best_sum; - - enum states - { + gr_complex d_sch_training_seq[N_SYNC_BITS]; //encoded training sequence of a SCH burst + + + enum states { fcch_search, sch_search } d_state; - friend gsm_receiver_cf_sptr gsm_make_receiver_cf( gr_feval_dd *tuner, int osr ); - gsm_receiver_cf( gr_feval_dd *tuner, int osr ); + friend gsm_receiver_cf_sptr gsm_make_receiver_cf(gr_feval_dd *tuner, int osr); + gsm_receiver_cf(gr_feval_dd *tuner, int osr); - bool find_fcch_burst( const gr_complex *in, const int nitems ); - bool find_sch_burst( const gr_complex *in, const int nitems , gr_complex *out); - double compute_freq_offset ( ); - void set_frequency ( ); + bool find_fcch_burst(const gr_complex *in, const int nitems); + double compute_freq_offset(); + void set_frequency(double freq_offset); + bool find_sch_burst(const gr_complex *in, const int nitems , float *out); + void gmsk_mapper(const int * input, gr_complex * gmsk_output, int ninput); + gr_complex correlation(const gr_complex * sequence, const gr_complex * input_signal, int ninput); public: ~gsm_receiver_cf(); - void forecast( int noutput_items, gr_vector_int &ninput_items_required ); - int general_work( int noutput_items, - gr_vector_int &ninput_items, - gr_vector_const_void_star &input_items, - gr_vector_void_star &output_items ); + void forecast(int noutput_items, gr_vector_int &ninput_items_required); + int general_work(int noutput_items, + gr_vector_int &ninput_items, + gr_vector_const_void_star &input_items, + gr_vector_void_star &output_items); }; #endif /* INCLUDED_GSM_RECEIVER_CF_H */ diff --git a/src/python/gsm_findfcch.py b/src/python/gsm_findfcch.py index 7ab9c18..9c0620b 100755 --- a/src/python/gsm_findfcch.py +++ b/src/python/gsm_findfcch.py @@ -10,7 +10,7 @@ from os import sys for extdir in ['../../debug/src/lib','../../debug/src/lib/.libs']: if extdir not in sys.path: sys.path.append(extdir) -import gsm +import gsm class tune(gr.feval_dd): def __init__(self, top_block): @@ -57,13 +57,13 @@ class gsm_receiver_first_blood(gr.top_block): self.clock_rate = clock_rate self.input_rate = clock_rate / options.decim self.gsm_symb_rate = 1625000.0 / 6.0 - self.sps = self.input_rate / self.gsm_symb_rate + self.sps = ( self.input_rate / self.gsm_symb_rate ) / options.osr def _ustaw_filtr(self): filter_cutoff = 145e3 filter_t_width = 10e3 offset = 0 - print "input_rate:", self.input_rate, "sample rate:", self.sps, " filter_cutoff:", filter_cutoff, " filter_t_width:", filter_t_width + #print "input_rate:", self.input_rate, "sample rate:", self.sps, " filter_cutoff:", filter_cutoff, " filter_t_width:", filter_t_width filter_taps = gr.firdes.low_pass(1.0, self.input_rate, filter_cutoff, filter_t_width, gr.firdes.WIN_HAMMING) filtr = gr.freq_xlating_fir_filter_ccf(1, filter_taps, offset, self.input_rate) return filtr |