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-rw-r--r--src/lib/gsm_receiver_cf.cc257
-rw-r--r--src/lib/gsm_receiver_cf.h32
2 files changed, 220 insertions, 69 deletions
diff --git a/src/lib/gsm_receiver_cf.cc b/src/lib/gsm_receiver_cf.cc
index 206bd5e..4f43f2b 100644
--- a/src/lib/gsm_receiver_cf.cc
+++ b/src/lib/gsm_receiver_cf.cc
@@ -27,14 +27,18 @@
#include <gsm_receiver_cf.h>
#include <gr_io_signature.h>
#include <gr_math.h>
+#include <math.h>
#include <gsm_constants.h>
#include <Assert.h>
+#include <algorithm>
+#define SAFETY_MARGIN 50
+#define BUFFER_SIZE (FCCH_HITS_NEEDED)
gsm_receiver_cf_sptr
-gsm_make_receiver_cf(int osr)
+gsm_make_receiver_cf(gr_feval_dd *tuner, int osr)
{
- return gsm_receiver_cf_sptr(new gsm_receiver_cf(osr));
+ return gsm_receiver_cf_sptr(new gsm_receiver_cf(tuner, osr));
}
static const int MIN_IN = 1; // mininum number of input streams
@@ -45,11 +49,19 @@ static const int MAX_OUT = 1; // maximum number of output streams
/*
* The private constructor
*/
-gsm_receiver_cf::gsm_receiver_cf(int osr)
+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_counter(0)
+ d_osr(osr),
+ d_tuner(tuner),
+ d_prev_freq_offset(0),
+ d_phase_diff_buffer(BUFFER_SIZE),
+ d_counter(0),
+ d_x_temp(0),
+ d_x2_temp(0),
+ d_fcch_count(0),
+ d_state(fcch_search)
{
}
@@ -73,76 +85,199 @@ 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;
-// DCOUT(ninput_items[0]);
-// DCOUT(noutput_items);
+ switch (d_state) {
+ case fcch_search:
- d_return = 0; //!
- int start_pos = find_fcch_burst(in, ninput_items[0]);
- for (int i = 0; i < TS_BITS; i++) {
- out[i] = d_phase_diff_buffer[i+start_pos-USEFUL_BITS];
+ if (find_fcch_burst(in, ninput_items[0])) {
+ produced_out = 1;
+ d_state = fcch_search;
+ } else {
+ produced_out = 0;
+ d_state = fcch_search;
+ }
+
+ break;
+
+ case sch_search:
+ break;
}
- consume_each(start_pos);
- d_counter += start_pos;
- return d_return;
+
+// for (int i = 0; i < TS_BITS; i++) {
+// out[i] = d_phase_diff_buffer[i+start_pos-USEFUL_BITS];
+// }
+
+ return produced_out;
}
-int gsm_receiver_cf::find_fcch_burst(const gr_complex *in, const int nitems)
+bool gsm_receiver_cf::find_fcch_burst(const gr_complex *in, const int nitems)
{
- for (int i = 0; (i < nitems - 1) && (i < BUFFER_SIZE); i++) {
- gr_complex conjprod = in[i+1] * conj(in[i]);
- float diff_angle = gr_fast_atan2f(imag(conjprod), real(conjprod));
- d_phase_diff_buffer[i] = diff_angle;
- }
+ float phase_diff = 0;
+ gr_complex conjprod;
+ int hit_count, miss_count, start_pos;
+ float min_phase_diff, max_phase_diff, lowest_max_min_diff;
+ float sum, best_sum;
- int hit_count = 0;
- int miss_count = 0;
- int start_pos = -1;
+ int to_consume = 0;
+ int i = 0;
+ bool end = false;
+ bool result;
- d_return = 0;//!
-
- for (int i = 0; ; i++) {
- if (i > nitems - USEFUL_BITS - 1) {
- start_pos = nitems - USEFUL_BITS - 1;
- break;
- }
+ circular_buffer_float::iterator buffer_iter;
- if (d_phase_diff_buffer[i] > 0) {
- if (! hit_count) {
- start_pos = i+USEFUL_BITS;
- }
- hit_count++;
- } else if (hit_count >= FCCH_HITS_NEEDED) {
- DCOUT("znalezione fcch na pozycji" << d_counter+start_pos-USEFUL_BITS);
- d_return = 1;//!
- break;
- } else if (++miss_count > FCCH_MAX_MISSES) {
- start_pos = -1;
- hit_count = miss_count = 0;
+ enum states {
+ init, search, found_something, fcch_found, search_fail
+ } fcch_search_state;
+
+ fcch_search_state = init;
+
+ while ((!end) && (i < nitems)) {
+ switch (fcch_search_state) {
+
+ case init:
+ hit_count = 0;
+ miss_count = 0;
+ start_pos = -1;
+ lowest_max_min_diff = 99999;
+ d_phase_diff_buffer.clear();
+ fcch_search_state = search;
+
+ break;
+
+ case search:
+ i++;
+
+ if (i > nitems - BUFFER_SIZE) {
+ to_consume = i;
+ fcch_search_state = search_fail;
+ }
+
+ conjprod = in[i] * conj(in[i-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;
+ }
+
+ break;
+
+ case found_something:
+
+ if (phase_diff > 0) {
+ hit_count++;
+ } else {
+ 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)) {
+ fcch_search_state = init;
+ continue;
+ } else if ((miss_count >= FCCH_MAX_MISSES) && (hit_count > FCCH_HITS_NEEDED)) {
+ fcch_search_state = fcch_found;
+ continue;
+ } else if ((miss_count < FCCH_MAX_MISSES) && (hit_count > FCCH_HITS_NEEDED)) {
+ //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){
+ lowest_max_min_diff = max_phase_diff - min_phase_diff;
+ start_pos = i - FCCH_HITS_NEEDED;
+ 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;
+ }
+ DCOUT(d_best_sum);
+ }
+ }
+
+ i++;
+
+ if (i >= nitems) {
+ fcch_search_state = search_fail;
+ continue;
+ }
+
+ conjprod = in[i] * conj(in[i-1]);
+ phase_diff = gr_fast_atan2f(imag(conjprod), real(conjprod));
+ d_phase_diff_buffer.push_back(phase_diff);
+
+ fcch_search_state = found_something;
+
+ break;
+
+ case fcch_found:
+ DCOUT("znalezione fcch na pozycji" << d_counter + start_pos);
+ to_consume = start_pos + FCCH_HITS_NEEDED + 1;
+ /* mean = d_best_sum / FCCH_HITS_NEEDED;
+ phase_offset = mean - (M_PI / 2);
+ freq_offset = phase_offset * 1625000.0 / (12.0 * M_PI);*/
+ compute_freq_offset();
+ end = true;
+ result = true;
+ break;
+
+ case search_fail:
+ end = true;
+ result = false;
+ break;
}
}
- /*
- //Do we have a match?
- if (start_pos >= 0) {
- //Is it within range? (we know it's long enough then too)
- if (start_pos < 2*MAX_CORR_DIST) {
- d_burst_start = start_pos;
- d_bbuf_pos = 0; //load buffer from start
- return FCCH;
- } else {
- //TODO: don't shift a tiny amount
- shift_burst(start_pos - MAX_CORR_DIST);
- }
- } else {
- //Didn't find anything
- d_burst_start = MAX_CORR_DIST;
- d_bbuf_pos = 0; //load buffer from start
- }
- */
- //DCOUT("start_pos: " << start_pos);
+ 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()
+{
+ float mean, phase_offset, 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);
+ freq_offset = phase_offset * 1625000.0 / (12.0 * M_PI);
+ DCOUT("freq_offset: " << freq_offset);
+ 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);
+
+ 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);
- return start_pos;
+ return freq_offset;
}
+void gsm_receiver_cf::set_frequency()
+{
+
+}
+
+bool gsm_receiver_cf::find_sch_burst( const gr_complex *in, const int nitems , gr_complex *out)
+{
+
+}
diff --git a/src/lib/gsm_receiver_cf.h b/src/lib/gsm_receiver_cf.h
index 5bc7617..2012325 100644
--- a/src/lib/gsm_receiver_cf.h
+++ b/src/lib/gsm_receiver_cf.h
@@ -24,8 +24,8 @@
#include <gr_block.h>
#include <gr_complex.h>
-
-#define BUFFER_SIZE 4096
+#include <gr_feval.h>
+#include <boost/circular_buffer.hpp>
class gsm_receiver_cf;
@@ -42,6 +42,8 @@ class gsm_receiver_cf;
*/
typedef boost::shared_ptr<gsm_receiver_cf> gsm_receiver_cf_sptr;
+typedef boost::circular_buffer<float> circular_buffer_float;
+
/*!
* \brief Return a shared_ptr to a new instance of gsm_receiver_cf.
*
@@ -49,7 +51,7 @@ typedef boost::shared_ptr<gsm_receiver_cf> gsm_receiver_cf_sptr;
* constructor is private. howto_make_square_ff is the public
* interface for creating new instances.
*/
-gsm_receiver_cf_sptr gsm_make_receiver_cf( int osr );
+gsm_receiver_cf_sptr gsm_make_receiver_cf( gr_feval_dd *tuner, int osr );
/*!
* \brief Receives fcch
@@ -61,13 +63,27 @@ class gsm_receiver_cf : public gr_block
{
private:
+ gr_feval_dd *d_tuner;
+ const int d_osr;
int d_counter;
- int d_return;
- float d_phase_diff_buffer[BUFFER_SIZE];
+ 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;
- friend gsm_receiver_cf_sptr gsm_make_receiver_cf( int osr );
- gsm_receiver_cf( int osr );
- int find_fcch_burst( const gr_complex *in, const int items );
+ 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 );
+
+ 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 ( );
public:
~gsm_receiver_cf();
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