/** This function is simply a wrapper to the ue_cell_search module for rf devices
* Return 1 if the MIB is decoded, 0 if not or -1 on error.
*/
int rf_mib_decoder(srslte_rf_t *rf, uint32_t nof_rx_antennas,cell_search_cfg_t *config, srslte_cell_t *cell, float *cfo) {
int ret = SRSLTE_ERROR;
srslte_ue_mib_sync_t ue_mib;
uint8_t bch_payload[SRSLTE_BCH_PAYLOAD_LEN];
if (srslte_ue_mib_sync_init_multi(&ue_mib, srslte_rf_recv_wrapper_cs, nof_rx_antennas, (void*) rf)) {
fprintf(stderr, "Error initiating srslte_ue_mib_sync\n");
goto clean_exit;
}
if (srslte_ue_mib_sync_set_cell(&ue_mib, cell->id, cell->cp)) {
fprintf(stderr, "Error initiating srslte_ue_mib_sync\n");
goto clean_exit;
}
int srate = srslte_sampling_freq_hz(SRSLTE_UE_MIB_NOF_PRB);
INFO("Setting sampling frequency %.2f MHz for PSS search\n", (float) srate/1000000);
srslte_rf_set_rx_srate(rf, (float) srate);
INFO("Starting receiver...\n");
srslte_rf_start_rx_stream(rf, false);
// Copy CFO estimate if provided and disable CP estimation during find
if (cfo) {
ue_mib.ue_sync.cfo_current_value = *cfo/15000;
ue_mib.ue_sync.cfo_is_copied = true;
ue_mib.ue_sync.cfo_correct_enable_find = true;
srslte_sync_set_cfo_cp_enable(&ue_mib.ue_sync.sfind, false, 0);
}
/* Find and decode MIB */
ret = srslte_ue_mib_sync_decode(&ue_mib, config->max_frames_pbch, bch_payload, &cell->nof_ports, NULL);
if (ret < 0) {
fprintf(stderr, "Error decoding MIB\n");
goto clean_exit;
}
if (ret == 1) {
srslte_pbch_mib_unpack(bch_payload, cell, NULL);
}
// Save CFO
if (cfo) {
*cfo = srslte_ue_sync_get_cfo(&ue_mib.ue_sync);
}
clean_exit:
srslte_rf_stop_rx_stream(rf);
srslte_ue_mib_sync_free(&ue_mib);
return ret;
}
int main(int argc, char **argv) {
int ret;
cf_t *sf_buffer;
prog_args_t prog_args;
srslte_cell_t cell;
int64_t sf_cnt;
srslte_ue_sync_t ue_sync;
srslte_ue_mib_t ue_mib;
void *uhd;
srslte_ue_dl_t ue_dl;
srslte_ofdm_t fft;
srslte_chest_dl_t chest;
uint32_t nframes=0;
uint32_t nof_trials = 0;
uint32_t sfn = 0; // system frame number
int n;
uint8_t bch_payload[SRSLTE_BCH_PAYLOAD_LEN];
uint32_t sfn_offset;
float rssi_utra=0,rssi=0, rsrp=0, rsrq=0, snr=0;
cf_t *ce[SRSLTE_MAX_PORTS];
if (parse_args(&prog_args, argc, argv)) {
exit(-1);
}
if (prog_args.uhd_gain > 0) {
printf("Opening UHD device...\n");
if (cuhd_open(prog_args.uhd_args, &uhd)) {
fprintf(stderr, "Error opening uhd\n");
exit(-1);
}
cuhd_set_rx_gain(uhd, prog_args.uhd_gain);
} else {
printf("Opening UHD device with threaded RX Gain control ...\n");
if (cuhd_open_th(prog_args.uhd_args, &uhd, false)) {
fprintf(stderr, "Error opening uhd\n");
exit(-1);
}
cuhd_set_rx_gain(uhd, 50);
}
sigset_t sigset;
sigemptyset(&sigset);
sigaddset(&sigset, SIGINT);
sigprocmask(SIG_UNBLOCK, &sigset, NULL);
signal(SIGINT, sig_int_handler);
cuhd_set_master_clock_rate(uhd, 30.72e6);
/* set receiver frequency */
cuhd_set_rx_freq(uhd, (double) prog_args.uhd_freq);
cuhd_rx_wait_lo_locked(uhd);
printf("Tunning receiver to %.3f MHz\n", (double ) prog_args.uhd_freq/1000000);
uint32_t ntrial=0;
do {
ret = cuhd_search_and_decode_mib(uhd, &cell_detect_config, prog_args.force_N_id_2, &cell);
if (ret < 0) {
fprintf(stderr, "Error searching for cell\n");
exit(-1);
} else if (ret == 0 && !go_exit) {
printf("Cell not found after %d trials. Trying again (Press Ctrl+C to exit)\n", ntrial++);
}
} while (ret == 0 && !go_exit);
if (go_exit) {
exit(0);
}
/* set sampling frequency */
int srate = srslte_sampling_freq_hz(cell.nof_prb);
if (srate != -1) {
if (srate < 10e6) {
cuhd_set_master_clock_rate(uhd, 4*srate);
} else {
cuhd_set_master_clock_rate(uhd, srate);
}
printf("Setting sampling rate %.2f MHz\n", (float) srate/1000000);
float srate_uhd = cuhd_set_rx_srate(uhd, (double) srate);
if (srate_uhd != srate) {
fprintf(stderr, "Could not set sampling rate\n");
exit(-1);
}
} else {
fprintf(stderr, "Invalid number of PRB %d\n", cell.nof_prb);
exit(-1);
}
INFO("Stopping UHD and flushing buffer...\n",0);
cuhd_stop_rx_stream(uhd);
cuhd_flush_buffer(uhd);
if (srslte_ue_sync_init(&ue_sync, cell, cuhd_recv_wrapper, uhd)) {
fprintf(stderr, "Error initiating ue_sync\n");
return -1;
}
if (srslte_ue_dl_init(&ue_dl, cell)) {
fprintf(stderr, "Error initiating UE downlink processing module\n");
return -1;
}
if (srslte_ue_mib_init(&ue_mib, cell)) {
fprintf(stderr, "Error initaiting UE MIB decoder\n");
return -1;
}
/* Configure downlink receiver for the SI-RNTI since will be the only one we'll use */
srslte_ue_dl_set_rnti(&ue_dl, SRSLTE_SIRNTI);
/* Initialize subframe counter */
sf_cnt = 0;
if (srslte_ofdm_rx_init(&fft, cell.cp, cell.nof_prb)) {
fprintf(stderr, "Error initiating FFT\n");
return -1;
}
if (srslte_chest_dl_init(&chest, cell)) {
fprintf(stderr, "Error initiating channel estimator\n");
return -1;
}
int sf_re = SRSLTE_SF_LEN_RE(cell.nof_prb, cell.cp);
cf_t *sf_symbols = srslte_vec_malloc(sf_re * sizeof(cf_t));
for (int i=0;i<SRSLTE_MAX_PORTS;i++) {
ce[i] = srslte_vec_malloc(sizeof(cf_t) * sf_re);
}
cuhd_start_rx_stream(uhd);
float rx_gain_offset = 0;
/* Main loop */
while ((sf_cnt < prog_args.nof_subframes || prog_args.nof_subframes == -1) && !go_exit) {
ret = srslte_ue_sync_get_buffer(&ue_sync, &sf_buffer);
if (ret < 0) {
fprintf(stderr, "Error calling srslte_ue_sync_work()\n");
}
/* srslte_ue_sync_get_buffer returns 1 if successfully read 1 aligned subframe */
if (ret == 1) {
switch (state) {
case DECODE_MIB:
if (srslte_ue_sync_get_sfidx(&ue_sync) == 0) {
srslte_pbch_decode_reset(&ue_mib.pbch);
n = srslte_ue_mib_decode(&ue_mib, sf_buffer, bch_payload, NULL, &sfn_offset);
if (n < 0) {
fprintf(stderr, "Error decoding UE MIB\n");
return -1;
} else if (n == SRSLTE_UE_MIB_FOUND) {
srslte_pbch_mib_unpack(bch_payload, &cell, &sfn);
printf("Decoded MIB. SFN: %d, offset: %d\n", sfn, sfn_offset);
sfn = (sfn + sfn_offset)%1024;
state = DECODE_SIB;
}
}
break;
case DECODE_SIB:
/* We are looking for SI Blocks, search only in appropiate places */
if ((srslte_ue_sync_get_sfidx(&ue_sync) == 5 && (sfn%2)==0)) {
n = srslte_ue_dl_decode_rnti_rv(&ue_dl, sf_buffer, data, srslte_ue_sync_get_sfidx(&ue_sync), SRSLTE_SIRNTI,
((int) ceilf((float)3*(((sfn)/2)%4)/2))%4);
if (n < 0) {
fprintf(stderr, "Error decoding UE DL\n");fflush(stdout);
return -1;
} else if (n == 0) {
printf("CFO: %+6.4f KHz, SFO: %+6.4f Khz, NOI: %.2f, PDCCH-Det: %.3f\r",
srslte_ue_sync_get_cfo(&ue_sync)/1000, srslte_ue_sync_get_sfo(&ue_sync)/1000,
srslte_sch_average_noi(&ue_dl.pdsch.dl_sch),
(float) ue_dl.nof_detected/nof_trials);
nof_trials++;
} else {
printf("Decoded SIB1. Payload: ");
srslte_vec_fprint_byte(stdout, data, n/8);;
state = MEASURE;
}
}
break;
case MEASURE:
if (srslte_ue_sync_get_sfidx(&ue_sync) == 5) {
/* Run FFT for all subframe data */
srslte_ofdm_rx_sf(&fft, sf_buffer, sf_symbols);
srslte_chest_dl_estimate(&chest, sf_symbols, ce, srslte_ue_sync_get_sfidx(&ue_sync));
rssi = SRSLTE_VEC_EMA(srslte_vec_avg_power_cf(sf_buffer,SRSLTE_SF_LEN(srslte_symbol_sz(cell.nof_prb))),rssi,0.05);
rssi_utra = SRSLTE_VEC_EMA(srslte_chest_dl_get_rssi(&chest),rssi_utra,0.05);
rsrq = SRSLTE_VEC_EMA(srslte_chest_dl_get_rsrq(&chest),rsrq,0.05);
rsrp = SRSLTE_VEC_EMA(srslte_chest_dl_get_rsrp(&chest),rsrp,0.05);
snr = SRSLTE_VEC_EMA(srslte_chest_dl_get_snr(&chest),snr,0.05);
nframes++;
}
if ((nframes%100) == 0 || rx_gain_offset == 0) {
if (cuhd_has_rssi(uhd)) {
rx_gain_offset = 10*log10(rssi)-cuhd_get_rssi(uhd);
} else {
rx_gain_offset = cuhd_get_rx_gain(uhd);
}
}
// Plot and Printf
if ((nframes%10) == 0) {
printf("CFO: %+8.4f KHz, SFO: %+8.4f Khz, RSSI: %5.1f dBm, RSSI/ref-symbol: %+5.1f dBm, "
"RSRP: %+5.1f dBm, RSRQ: %5.1f dB, SNR: %5.1f dB\r",
srslte_ue_sync_get_cfo(&ue_sync)/1000, srslte_ue_sync_get_sfo(&ue_sync)/1000,
10*log10(rssi*1000) - rx_gain_offset,
10*log10(rssi_utra*1000)- rx_gain_offset,
10*log10(rsrp*1000) - rx_gain_offset,
10*log10(rsrq), 10*log10(snr));
if (srslte_verbose != SRSLTE_VERBOSE_NONE) {
printf("\n");
}
}
break;
}
if (srslte_ue_sync_get_sfidx(&ue_sync) == 9) {
sfn++;
if (sfn == 1024) {
sfn = 0;
}
}
} else if (ret == 0) {
printf("Finding PSS... Peak: %8.1f, FrameCnt: %d, State: %d\r",
srslte_sync_get_peak_value(&ue_sync.sfind),
ue_sync.frame_total_cnt, ue_sync.state);
}
sf_cnt++;
} // Main loop
srslte_ue_sync_free(&ue_sync);
cuhd_close(uhd);
printf("\nBye\n");
exit(0);
}
/** Finds a cell for a given N_id_2 and stores ID and CP in the structure pointed by found_cell.
* Returns 1 if the cell is found, 0 if not or -1 on error
*/
int srslte_ue_cellsearch_scan_N_id_2(srslte_ue_cellsearch_t * q,
uint32_t N_id_2,
srslte_ue_cellsearch_result_t *found_cell)
{
int ret = SRSLTE_ERROR_INVALID_INPUTS;
uint32_t nof_detected_frames = 0;
uint32_t nof_scanned_frames = 0;
if (q != NULL)
{
ret = SRSLTE_SUCCESS;
bzero(q->candidates, sizeof(srslte_ue_cellsearch_result_t)*q->max_frames);
bzero(q->mode_ntimes, sizeof(uint32_t)*q->max_frames);
bzero(q->mode_counted, sizeof(uint8_t)*q->max_frames);
srslte_ue_sync_set_N_id_2(&q->ue_sync, N_id_2);
srslte_ue_sync_reset(&q->ue_sync);
srslte_ue_sync_cfo_reset(&q->ue_sync);
do {
ret = srslte_ue_sync_zerocopy_multi(&q->ue_sync, q->sf_buffer);
if (ret < 0) {
fprintf(stderr, "Error calling srslte_ue_sync_work()\n");
return -1;
} else if (ret == 1) {
/* This means a peak was found and ue_sync is now in tracking state */
ret = srslte_sync_get_cell_id(&q->ue_sync.strack);
if (ret >= 0) {
/* Save cell id, cp and peak */
q->candidates[nof_detected_frames].cell_id = (uint32_t) ret;
q->candidates[nof_detected_frames].cp = srslte_sync_get_cp(&q->ue_sync.strack);
q->candidates[nof_detected_frames].peak = q->ue_sync.strack.pss.peak_value;
q->candidates[nof_detected_frames].psr = srslte_sync_get_peak_value(&q->ue_sync.strack);
q->candidates[nof_detected_frames].cfo = srslte_ue_sync_get_cfo(&q->ue_sync);
DEBUG
("CELL SEARCH: [%3d/%3d/%d]: Found peak PSR=%.3f, Cell_id: %d CP: %s\n",
nof_detected_frames, nof_scanned_frames, q->nof_valid_frames,
q->candidates[nof_detected_frames].psr, q->candidates[nof_detected_frames].cell_id,
srslte_cp_string(q->candidates[nof_detected_frames].cp));
nof_detected_frames++;
}
} else if (ret == 0) {
/* This means a peak is not yet found and ue_sync is in find state
* Do nothing, just wait and increase nof_scanned_frames counter.
*/
}
nof_scanned_frames++;
} while (nof_scanned_frames < q->max_frames && nof_detected_frames < q->nof_valid_frames);
/* In either case, check if the mean PSR is above the minimum threshold */
if (nof_detected_frames > 0) {
ret = 1; // A cell has been found.
if (found_cell) {
get_cell(q, nof_detected_frames, found_cell);
}
} else {
ret = 0; // A cell was not found.
}
}
return ret;
}
