summaryrefslogtreecommitdiff
path: root/src/lib
diff options
context:
space:
mode:
Diffstat (limited to 'src/lib')
-rw-r--r--src/lib/gsm_constants.h2
-rw-r--r--src/lib/gsm_receiver_cf.cc16
-rw-r--r--src/lib/gsm_receiver_cf.h2
3 files changed, 15 insertions, 5 deletions
diff --git a/src/lib/gsm_constants.h b/src/lib/gsm_constants.h
index 3f7ef04..1ebce1c 100644
--- a/src/lib/gsm_constants.h
+++ b/src/lib/gsm_constants.h
@@ -33,6 +33,8 @@
#define CHAN_IMP_RESP_LENGTH 5
+#define MAX_SCH_ERRORS 2 //maximum number of subsequent sch errors after which gsm receiver goes to find_next_fcch state
+
typedef enum {empty, fcch_burst, sch_burst, normal_burst, rach_burst, dummy} burst_type;
typedef enum {unknown, multiframe_26, multiframe_51} multiframe_type;
diff --git a/src/lib/gsm_receiver_cf.cc b/src/lib/gsm_receiver_cf.cc
index 7f91fa8..0fde642 100644
--- a/src/lib/gsm_receiver_cf.cc
+++ b/src/lib/gsm_receiver_cf.cc
@@ -55,10 +55,10 @@ void gsm_receiver_cf::process_normal_burst(burst_counter burst_nr, const unsigne
void gsm_receiver_cf::configure_receiver()
{
d_channel_conf.set_multiframe_type(TSC0, multiframe_51);
-
+
d_channel_conf.set_burst_types(TSC0, TEST_CCH_FRAMES, sizeof(TEST_CCH_FRAMES) / sizeof(unsigned), normal_burst);
d_channel_conf.set_burst_types(TSC0, FCCH_FRAMES, sizeof(FCCH_FRAMES) / sizeof(unsigned), fcch_burst);
-
+
// d_channel_conf.set_multiframe_type(TIMESLOT6, multiframe_26);
// d_channel_conf.set_burst_types(TIMESLOT6, TRAFFIC_CHANNEL_F, sizeof(TRAFFIC_CHANNEL_F) / sizeof(unsigned), normal_burst);
}
@@ -94,7 +94,8 @@ 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_burst_nr(osr)
+ d_burst_nr(osr),
+ d_failed_sch(0)
{
int i;
gmsk_mapper(SYNC_BITS, N_SYNC_BITS, d_sch_training_seq, gr_complex(0.0, -1.0));
@@ -102,7 +103,7 @@ gsm_receiver_cf::gsm_receiver_cf(gr_feval_dd *tuner, int osr)
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));
}
-
+
/* Initialize GSM Stack */
GS_new(&d_gs_ctx); //TODO: remove it! it'a not right place for a decoder
}
@@ -218,10 +219,16 @@ gsm_receiver_cf::general_work(int noutput_items,
detect_burst(input, &channel_imp_resp[0], burst_start, output_binary); //MLSE detection of bits
if (decode_sch(&output_binary[3], &t1, &t2, &t3, &d_ncc, &d_bcc) == 0) { //and decode SCH data
// d_burst_nr.set(t1, t2, t3, 0); //but only to check if burst_start value is correct
+ d_failed_sch = 0;
DCOUT("bcc: " << d_bcc << " ncc: " << d_ncc << " t1: " << t1 << " t2: " << t2 << " t3: " << t3);
offset = burst_start - floor((GUARD_PERIOD) * d_OSR); //compute offset from burst_start - burst should start after a guard period
DCOUT(offset);
to_consume += offset; //adjust with offset number of samples to be consumed
+ } else {
+ d_failed_sch++;
+ if(d_failed_sch >= MAX_SCH_ERRORS){
+ d_state = next_fcch_search;
+ }
}
}
break;
@@ -680,6 +687,5 @@ int gsm_receiver_cf::get_norm_chan_imp_resp(const gr_complex *input, gr_complex
//std::cout << " burst_start: " << burst_start << " center: " << ((float)(search_start_pos + strongest_window_nr + chan_imp_resp_center)) / d_OSR << " stronegest window nr: " << strongest_window_nr << "\n";
return burst_start;
-
}
diff --git a/src/lib/gsm_receiver_cf.h b/src/lib/gsm_receiver_cf.h
index af13618..c37813a 100644
--- a/src/lib/gsm_receiver_cf.h
+++ b/src/lib/gsm_receiver_cf.h
@@ -96,6 +96,8 @@ class gsm_receiver_cf : public gr_block
channel_configuration d_channel_conf; ///< mapping of burst_counter to burst_type
//@}
+ unsigned d_failed_sch; ///< number of subsequent erroneous SCH bursts
+
// GSM Stack
GS_CTX d_gs_ctx;//TODO: remove it! it'a not right place for a decoder
personal git repositories of Harald Welte. Your mileage may vary