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fixing "making SFN dependent on GPS time"

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in fact it syncs the USRP time to GPS time when available and then derives the SFN from the USRP time.
a side effect is that now SFN does not necessarily start at 0 and this also required other changes
 - initialization of the future_ul_tti_request.
 - fixing a bug in get_samples_per_slot
This commit is contained in:
Florian Kaltenberger
2022-04-06 17:40:14 +02:00
parent 5b22d94d37
commit 367ad780a4
4 changed files with 37 additions and 27 deletions
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targets/ARCH/USRP/USERSPACE/LIB/usrp_lib.cpp
+19 -19
View File
@@ -203,8 +203,8 @@ static int sync_to_gps(openair0_device *device) {
//Set to GPS time
uhd::time_spec_t gps_time = uhd::time_spec_t(time_t(s->usrp->get_mboard_sensor("gps_time", mboard).to_int()));
//s->usrp->set_time_next_pps(gps_time+1.0, mboard);
s->usrp->set_time_next_pps(uhd::time_spec_t(0.0));
s->usrp->set_time_next_pps(gps_time+1.0, mboard);
//s->usrp->set_time_next_pps(uhd::time_spec_t(0.0));
//Wait for it to apply
//The wait is 2 seconds because N-Series has a known issue where
//the time at the last PPS does not properly update at the PPS edge
@@ -215,10 +215,10 @@ static int sync_to_gps(openair0_device *device) {
uhd::time_spec_t time_last_pps = s->usrp->get_time_last_pps(mboard);
std::cout << "USRP time: " << (boost::format("%0.9f") % time_last_pps.get_real_secs()) << std::endl;
std::cout << "GPSDO time: " << (boost::format("%0.9f") % gps_time.get_real_secs()) << std::endl;
//if (gps_time.get_real_secs() == time_last_pps.get_real_secs())
// std::cout << std::endl << "SUCCESS: USRP time synchronized to GPS time" << std::endl << std::endl;
//else
// std::cerr << std::endl << "ERROR: Failed to synchronize USRP time to GPS time" << std::endl << std::endl;
if (gps_time.get_real_secs() == time_last_pps.get_real_secs())
std::cout << std::endl << "SUCCESS: USRP time synchronized to GPS time" << std::endl << std::endl;
else
std::cerr << std::endl << "ERROR: Failed to synchronize USRP time to GPS time" << std::endl << std::endl;
}
if (num_gps_locked == num_mboards and num_mboards > 1) {
@@ -293,15 +293,11 @@ static int trx_usrp_start(openair0_device *device) {
//s->first_rx = 1;
s->rx_timestamp = 0;
s->usrp->set_time_next_pps(uhd::time_spec_t(0.0));
// wait for the pps to change
uhd::time_spec_t time_last_pps = s->usrp->get_time_last_pps();
while (time_last_pps == s->usrp->get_time_last_pps()) {
boost::this_thread::sleep(boost::posix_time::milliseconds(1));
}
LOG_I(HW,"last pps at %f, starting streaming at %f\n",time_last_pps.get_real_secs(),time_last_pps.get_real_secs()+1.0);
uhd::stream_cmd_t cmd(uhd::stream_cmd_t::STREAM_MODE_START_CONTINUOUS);
cmd.time_spec = uhd::time_spec_t(1.0);
cmd.time_spec = uhd::time_spec_t(time_last_pps+1.0);
cmd.stream_now = false; // start at constant delay
s->rx_stream->issue_stream_cmd(cmd);
@@ -1103,12 +1099,16 @@ extern "C" {
LOG_I(HW,"USRP fails to sync with GPS. Exiting.\n");
exit(EXIT_FAILURE);
}
} else if (s->usrp->get_clock_source(0) == "external") {
if (check_ref_locked(s,0)) {
LOG_I(HW,"USRP locked to external reference!\n");
} else {
LOG_I(HW,"Failed to lock to external reference. Exiting.\n");
exit(EXIT_FAILURE);
} else {
s->usrp->set_time_next_pps(uhd::time_spec_t(0.0));
if (s->usrp->get_clock_source(0) == "external") {
if (check_ref_locked(s,0)) {
LOG_I(HW,"USRP locked to external reference!\n");
} else {
LOG_I(HW,"Failed to lock to external reference. Exiting.\n");
exit(EXIT_FAILURE);
}
}
}
@@ -1322,7 +1322,7 @@ extern "C" {
LOG_I(HW,"Actual master clock: %fMHz...\n",s->usrp->get_master_clock_rate()/1e6);
LOG_I(HW,"Actual clock source %s...\n",s->usrp->get_clock_source(0).c_str());
LOG_I(HW,"Actual time source %s...\n",s->usrp->get_time_source(0).c_str());
sleep(1);
// create tx & rx streamer
uhd::stream_args_t stream_args_rx("sc16", "sc16");
int samples=openair0_cfg[0].sample_rate;