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authorPiotr Krysik <perper@o2.pl>2009-04-30 19:07:08 +0200
committerPiotr Krysik <perper@o2.pl>2009-04-30 19:07:08 +0200
commit5027749b23b0b4a49d166aee6712b7de01a3d54c (patch)
tree8ff7935aa5b9678deff2534037ad4376a57aa520 /src/lib
parent961ff106d137b744eeafae55c939a5524370267b (diff)
liettle changes to fcch search, commit before test to find reason of bad behavior when OSR value is changed
Diffstat (limited to 'src/lib')
-rw-r--r--src/lib/Assert.h2
-rw-r--r--src/lib/gsm_receiver_cf.cc178
-rw-r--r--src/lib/gsm_receiver_cf.h16
3 files changed, 118 insertions, 78 deletions
diff --git a/src/lib/Assert.h b/src/lib/Assert.h
index acfb3f7..67fe02f 100644
--- a/src/lib/Assert.h
+++ b/src/lib/Assert.h
@@ -26,7 +26,7 @@
#include "stdio.h"
#include <iostream>
-#define NDEBUG
+//#define NDEBUG
/**@name Macros for standard messages. */
//@{
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
+}
diff --git a/src/lib/gsm_receiver_cf.h b/src/lib/gsm_receiver_cf.h
index ccc99fb..d4e26e5 100644
--- a/src/lib/gsm_receiver_cf.h
+++ b/src/lib/gsm_receiver_cf.h
@@ -25,8 +25,8 @@
#include <gr_block.h>
#include <gr_complex.h>
#include <gr_feval.h>
-#include <boost/circular_buffer.hpp>
#include <gsm_constants.h>
+#include <vector>
class gsm_receiver_cf;
@@ -43,8 +43,7 @@ class gsm_receiver_cf;
* As a convention, the _sptr suffix indicates a boost::shared_ptr
*/
typedef boost::shared_ptr<gsm_receiver_cf> gsm_receiver_cf_sptr;
-
-typedef boost::circular_buffer<float> circular_buffer_float;
+typedef std::vector<gr_complex> vector_complex;
/*!
* \brief Return a shared_ptr to a new instance of gsm_receiver_cf.
@@ -75,12 +74,11 @@ class gsm_receiver_cf : public gr_block
int d_fcch_start_pos;
float d_freq_offset;
double d_best_sum;
-
- int d_fcch_count;
- bool d_first;
-// int d_fcch_count;
-// double d_x_temp, d_x2_temp, d_mean;
+ int d_fcch_count; //!!!
+ double d_x_temp, d_x2_temp, d_mean;//!!
+
+ vector_complex d_channel_imp_resp;
enum states {
first_fcch_search, next_fcch_search, sch_search, read_bcch
@@ -96,7 +94,7 @@ class gsm_receiver_cf : public gr_block
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);
+ gr_complex correlate_sequence(const gr_complex * sequence, const gr_complex * input_signal, int ninput);
public:
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