Commit 367ad780 authored by Florian Kaltenberger's avatar Florian Kaltenberger

fixing "making SFN dependent on GPS time"

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
parent 5b22d94d
......@@ -604,6 +604,7 @@ void *emulatedRF_thread(void *param) {
void rx_rf(RU_t *ru,int *frame,int *slot) {
RU_proc_t *proc = &ru->proc;
NR_DL_FRAME_PARMS *fp = ru->nr_frame_parms;
openair0_config_t *cfg = &ru->openair0_cfg;
void *rxp[ru->nb_rx];
unsigned int rxs;
int i;
......@@ -641,8 +642,8 @@ void rx_rf(RU_t *ru,int *frame,int *slot) {
if (rxs != samples_per_slot) LOG_E(PHY, "rx_rf: Asked for %d samples, got %d from USRP\n",samples_per_slot,rxs);
if (proc->first_rx == 1) {
ru->ts_offset = proc->timestamp_rx;
proc->timestamp_rx = 0;
//ru->ts_offset = proc->timestamp_rx;
//proc->timestamp_rx = 0;
} else {
samples_per_slot_prev = fp->get_samples_per_slot((*slot-1)%fp->slots_per_frame,fp);
......@@ -653,13 +654,22 @@ void rx_rf(RU_t *ru,int *frame,int *slot) {
}
}
//compute system frame number (SFN) according to O-RAN-WG4-CUS.0-v02.00 (using alpha=beta=0)
// this assumes that the USRP has been synchronized to the GPS time
// OAI uses timestamps in sample time stored in int64_t, but it will fit in double precision for many years to come.
double gps_sec = ((double) ts)/cfg->sample_rate;
//proc->frame_rx = ((int64_t) (gps_sec/0.01)) & 1023;
// in fact the following line is the same as long as the timestamp_rx is synchronized to GPS.
proc->frame_rx = (proc->timestamp_rx / (fp->samples_per_subframe*10))&1023;
proc->tti_rx = fp->get_slot_from_timestamp(proc->timestamp_rx,fp);
// synchronize first reception to frame 0 subframe 0
LOG_D(PHY,"RU %d/%d TS %llu , frame %d, slot %d.%d / %d\n",
LOG_D(PHY,"RU %d/%d TS %ld, GPS %f, SR %f, frame %d, slot %d.%d / %d\n",
ru->idx,
0,
(unsigned long long int)(proc->timestamp_rx+ru->ts_offset),
ts, //(unsigned long long int)(proc->timestamp_rx+ru->ts_offset),
gps_sec,
cfg->sample_rate,
proc->frame_rx,proc->tti_rx,proc->tti_tx,fp->slots_per_frame);
// dump VCD output for first RU in list
......
......@@ -212,12 +212,12 @@ uint32_t get_samples_per_slot(int slot, NR_DL_FRAME_PARMS* fp)
uint32_t get_slot_from_timestamp(openair0_timestamp timestamp_rx, NR_DL_FRAME_PARMS* fp)
{
uint32_t slot_idx = 0;
int samples_till_the_slot = 0;
int samples_till_the_slot = fp->get_samples_per_slot(slot_idx,fp)-1;
timestamp_rx = timestamp_rx%fp->samples_per_frame;
while (timestamp_rx > samples_till_the_slot) {
samples_till_the_slot += fp->get_samples_per_slot(slot_idx,fp);
slot_idx++;
samples_till_the_slot += fp->get_samples_per_slot(slot_idx,fp);
}
return slot_idx;
}
......
......@@ -69,7 +69,7 @@ void clear_nr_nfapi_information(gNB_MAC_INST * gNB,
nfapi_nr_dl_tti_request_t *DL_req = &gNB->DL_req[0];
nfapi_nr_dl_tti_pdcch_pdu_rel15_t ***pdcch = (nfapi_nr_dl_tti_pdcch_pdu_rel15_t ***)gNB->pdcch_pdu_idx[CC_idP];
nfapi_nr_ul_tti_request_t *future_ul_tti_req =
&gNB->UL_tti_req_ahead[CC_idP][(slotP + num_slots - 1) % num_slots];
&gNB->UL_tti_req_ahead[CC_idP][(slotP+6)]; // + num_slots - 1) % num_slots];
nfapi_nr_ul_dci_request_t *UL_dci_req = &gNB->UL_dci_req[0];
nfapi_nr_tx_data_request_t *TX_req = &gNB->TX_req[0];
......@@ -87,7 +87,7 @@ void clear_nr_nfapi_information(gNB_MAC_INST * gNB,
UL_dci_req[CC_idP].numPdus = 0;
/* advance last round's future UL_tti_req to be ahead of current frame/slot */
future_ul_tti_req->SFN = (slotP == 0 ? frameP : frameP + 1) % 1024;
future_ul_tti_req->SFN = ((slotP+6<num_slots) ? frameP : frameP + 1) % 1024;
LOG_D(MAC,"Future_ul_tti SFN = %d for slot %d \n", future_ul_tti_req->SFN, (slotP + num_slots - 1) % num_slots);
/* future_ul_tti_req->Slot is fixed! */
future_ul_tti_req->n_pdus = 0;
......
......@@ -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;
......
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