Added timestamping of bursts in the gsm receiver
diff --git a/lib/receiver/receiver_impl.cc b/lib/receiver/receiver_impl.cc
index b7c5be2..db7d9dd 100644
--- a/lib/receiver/receiver_impl.cc
+++ b/lib/receiver/receiver_impl.cc
@@ -74,10 +74,12 @@
) : gr::sync_block("receiver",
gr::io_signature::make(1, -1, sizeof(gr_complex)),
gr::io_signature::make(0, 0, 0)),
+ d_rx_time_received(false),
+ d_time_samp_ref(GSM_SYMBOL_RATE * osr),
d_OSR(osr),
d_process_uplink(process_uplink),
d_chan_imp_length(CHAN_IMP_RESP_LENGTH),
- d_counter(0),
+ d_counter(0), //TODO: use nitems_read instead of d_counter
d_fcch_start_pos(0),
d_freq_offset_setting(0),
d_state(fcch_search),
@@ -147,6 +149,7 @@
std::vector<const gr_complex *> iii =
(std::vector<const gr_complex *>) input_items;
#endif
+
/* Time synchronization loop */
float current_time =
@@ -175,7 +178,25 @@
d_freq_offset_tag_in_fcch = tag_offset < last_sample_nr;
}
}
+
+ /* Obtaining current time with use of rx_time tag provided i.e. by UHD devices */
+ /* And storing it in time_sample_ref for sample number to time conversion */
+ std::vector<tag_t> rx_time_tags;
+ get_tags_in_window(rx_time_tags, 0, 0, noutput_items, pmt::string_to_symbol("rx_time"));
+ if(!rx_time_tags.empty()){
+ d_rx_time_received = true;
+ tag_t rx_time_tag = *(rx_time_tags.begin());
+
+ uint64_t rx_time_full_part = to_uint64(tuple_ref(rx_time_tag.value,0));
+ double rx_time_frac_part = to_double(tuple_ref(rx_time_tag.value,1));
+
+ time_spec_t current_rx_time = time_spec_t(rx_time_full_part, rx_time_frac_part);
+ uint64_t current_start_offset = rx_time_tag.offset;
+ d_time_samp_ref.update(current_rx_time, current_start_offset);
+// std::cout << "Mam rx_time: " << current_rx_time.get_real_secs() << std::endl;
+ }
+
/* Main state machine */
switch (d_state) {
case fcch_search:
@@ -335,7 +356,7 @@
/* Compose a message with GSMTAP header and bits */
send_burst(d_burst_nr, output_binary,
- GSMTAP_BURST_SCH, input_nr);
+ GSMTAP_BURST_SCH, input_nr, d_c0_burst_start);
/* Attempt to decode SCH burst */
rc = decode_sch(&output_binary[3], &t1, &t2, &t3, &d_ncc, &d_bcc);
@@ -381,7 +402,7 @@
/* Compose a message with GSMTAP header and bits */
send_burst(d_burst_nr, output_binary,
- GSMTAP_BURST_NORMAL, input_nr);
+ GSMTAP_BURST_NORMAL, input_nr, d_c0_burst_start);
break;
}
@@ -405,13 +426,13 @@
/* Compose a message with GSMTAP header and bits */
send_burst(d_burst_nr, output_binary,
- GSMTAP_BURST_NORMAL, input_nr);
+ GSMTAP_BURST_NORMAL, input_nr, normal_burst_start);
} else {
d_c0_burst_start = dummy_burst_start;
/* Compose a message with GSMTAP header and bits */
send_burst(d_burst_nr, dummy_burst,
- GSMTAP_BURST_DUMMY, input_nr);
+ GSMTAP_BURST_DUMMY, input_nr, dummy_burst_start);
}
break;
@@ -463,7 +484,7 @@
burst_start, output_binary);
/* Compose a message with GSMTAP header and bits */
- send_burst(d_burst_nr, output_binary, GSMTAP_BURST_NORMAL, input_nr);
+ send_burst(d_burst_nr, output_binary, GSMTAP_BURST_NORMAL, input_nr, burst_start);
break;
}
@@ -980,7 +1001,7 @@
void
receiver_impl::send_burst(burst_counter burst_nr,
const unsigned char * burst_binary, uint8_t burst_type,
- unsigned int input_nr)
+ unsigned int input_nr, unsigned int burst_start)
{
/* Buffer for GSMTAP header and burst */
uint8_t buf[sizeof(gsmtap_hdr) + BURST_SIZE];
@@ -1019,6 +1040,17 @@
tap_header->signal_dbm = static_cast<int8_t>(d_signal_dbm);
tap_header->snr_db = 0; /* FIXME: Can we calculate this? */
+ pmt::pmt_t pdu_header = pmt::make_dict();
+
+ /* Add timestamp of the first sample - if available */
+ if(d_rx_time_received) {
+ time_spec_t time_spec_of_first_sample = d_time_samp_ref.offset_to_time(nitems_read(0)+burst_start);
+ uint64_t full = time_spec_of_first_sample.get_full_secs();
+ double frac = time_spec_of_first_sample.get_frac_secs();
+ pdu_header =
+ pmt::dict_add(pdu_header, pmt::mp("fn_time"), pmt::cons(pmt::from_uint64(frame_number), pmt::cons(pmt::from_uint64(full), pmt::from_double(frac))));
+ }
+
/* Copy burst to the buffer */
memcpy(burst, burst_binary, BURST_SIZE);
@@ -1093,6 +1125,5 @@
{
d_state = fcch_search;
}
-
} /* namespace gsm */
} /* namespace gr */