int find_cell(void *uhd, ue_celldetect_t *s, cf_t *buffer, ue_celldetect_result_t found_cell[3])
{
int n;
INFO("Setting sampling frequency 960 KHz for PSS search\n", 0);
cuhd_set_rx_srate(uhd, 960000.0);
INFO("Starting receiver...\n", 0);
cuhd_start_rx_stream(uhd);
uint32_t nof_scanned_cells = 0;
uint32_t flen = 4800;
int nof_detected_cells = 0;
do {
if (cuhd_recv(uhd, buffer, flen, 1)<0) {
fprintf(stderr, "Error receiving from USRP\n");
return LIBLTE_ERROR;
}
n = ue_celldetect_scan(s, buffer, flen, &found_cell[nof_scanned_cells]);
switch(n) {
case CS_FRAME_UNALIGNED:
printf("Realigning frame\n");
if (cuhd_recv(uhd, buffer, flen/2, 1)<0) {
fprintf(stderr, "Error receiving from USRP\n");
return LIBLTE_ERROR;
}
return LIBLTE_ERROR;
case CS_CELL_DETECTED:
nof_detected_cells++;
if (found_cell[nof_scanned_cells].peak > 0) {
printf("\n\tCELL ID: %d, CP: %s, Peak: %.2f, Mode: %d/%d\n",
found_cell[nof_scanned_cells].cell_id,
lte_cp_string(found_cell[nof_scanned_cells].cp),
found_cell[nof_scanned_cells].peak, found_cell[nof_scanned_cells].mode,
s->nof_frames_detected);
}
nof_scanned_cells++;
break;
case CS_CELL_NOT_DETECTED:
nof_scanned_cells++;
break;
case LIBLTE_ERROR:
case LIBLTE_ERROR_INVALID_INPUTS:
fprintf(stderr, "Error calling cellsearch_scan()\n");
return LIBLTE_ERROR;
}
} while(nof_scanned_cells < 3);
INFO("Stopping receiver...\n", 0);
cuhd_stop_rx_stream(uhd);
cuhd_flush_buffer(uhd);
return nof_detected_cells;
}
int decode_pbch(void *uhd, cf_t *buffer, ue_celldetect_result_t *found_cell, uint32_t nof_frames_total, pbch_mib_t *mib)
{
ue_mib_t uemib;
int n;
bzero(mib, sizeof(pbch_mib_t));
uint32_t nof_frames = 0;
uint32_t flen = MIB_FRAME_SIZE;
if (ue_mib_init(&uemib, found_cell->cell_id, found_cell->cp)) {
fprintf(stderr, "Error initiating PBCH decoder\n");
return LIBLTE_ERROR;
}
INFO("Setting sampling frequency 1.92 MHz for PBCH decoding\n", 0);
cuhd_set_rx_srate(uhd, 1920000.0);
INFO("Starting receiver...\n", 0);
cuhd_start_rx_stream(uhd);
do {
if (cuhd_recv(uhd, buffer, flen, 1)<0) {
fprintf(stderr, "Error receiving from USRP\n");
return LIBLTE_ERROR;
}
INFO("Calling ue_mib_decode() %d/%d\n", nof_frames, nof_frames_total);
n = ue_mib_decode(&uemib, buffer, flen, mib);
if (n == LIBLTE_ERROR || n == LIBLTE_ERROR_INVALID_INPUTS) {
fprintf(stderr, "Error calling ue_mib_decode()\n");
return LIBLTE_ERROR;
}
if (n == MIB_FRAME_UNALIGNED) {
printf("Realigning frame\n");
if (cuhd_recv(uhd, buffer, flen/2, 1)<0) {
fprintf(stderr, "Error receiving from USRP\n");
return LIBLTE_ERROR;
}
}
nof_frames++;
} while (n != MIB_FOUND && nof_frames < 2*nof_frames_total);
if (n == MIB_FOUND) {
printf("\n\nMIB decoded in %d ms (%d half frames)\n", nof_frames*5, nof_frames);
pbch_mib_fprint(stdout, mib, found_cell->cell_id);
} else {
printf("\nCould not decode MIB\n");
}
cuhd_stop_rx_stream(uhd);
cuhd_flush_buffer(uhd);
ue_mib_free(&uemib);
return LIBLTE_SUCCESS;
}
void cuhd_flush_buffer(void *h)
{
int n;
_Complex float tmp[1024];
do {
n = cuhd_recv(h, tmp, 1024, 0);
} while (n > 0);
}
int cuhd_rssi_scan(void *uhd, float *freqs, float *rssi, int nof_bands, double fs, int nsamp) {
int i, j;
int ret = -1;
_Complex float *buffer;
double f;
buffer = calloc(nsamp, sizeof(_Complex float));
if (!buffer) {
goto free_and_exit;
}
cuhd_set_rx_gain(uhd, 20.0);
cuhd_set_rx_srate(uhd, fs);
for (i=0;i<nof_bands;i++) {
cuhd_stop_rx_stream(uhd);
f = (double) freqs[i];
cuhd_set_rx_freq(uhd, f);
cuhd_rx_wait_lo_locked(uhd);
usleep(10000);
cuhd_start_rx_stream(uhd);
/* discard first samples */
for (j=0;j<2;j++) {
if (cuhd_recv(uhd, buffer, nsamp, 1) != nsamp) {
goto free_and_exit;
}
}
rssi[i] = srslte_vec_avg_power_cf(buffer, nsamp);
printf("[%3d]: Freq %4.1f Mhz - RSSI: %3.2f dBm\r", i, f/1000000, 10*log10f(rssi[i]) + 30); fflush(stdout);
if (SRSLTE_VERBOSE_ISINFO()) {
printf("\n");
}
}
cuhd_stop_rx_stream(uhd);
ret = 0;
free_and_exit:
free(buffer);
return ret;
}
int cuhd_recv_wrapper(void *h, void *data, uint32_t nsamples, srslte_timestamp_t *q) {
DEBUG(" ---- Receive %d samples ---- \n", nsamples);
return cuhd_recv(h, data, nsamples, 1);
}
int main(int argc, char **argv) {
cf_t *buffer;
int frame_cnt, n;
void *uhd;
srslte_pss_synch_t pss;
srslte_cfo_t cfocorr, cfocorr64;
srslte_sss_synch_t sss;
int32_t flen;
int peak_idx, last_peak;
float peak_value;
float mean_peak;
uint32_t nof_det, nof_nodet, nof_nopeak, nof_nopeakdet;
cf_t ce[SRSLTE_PSS_LEN];
parse_args(argc, argv);
if (N_id_2_sync == -1) {
N_id_2_sync = cell_id%3;
}
uint32_t N_id_2 = cell_id%3;
uint32_t N_id_1 = cell_id/3;
#ifndef DISABLE_GRAPHICS
if (!disable_plots)
init_plots();
#endif
float srate = 15000.0*fft_size;
flen = srate*5/1000;
printf("Opening UHD device...\n");
if (cuhd_open(uhd_args, &uhd)) {
fprintf(stderr, "Error opening uhd\n");
exit(-1);
}
if (srate < 10e6) {
cuhd_set_master_clock_rate(uhd, 4*srate);
} else {
cuhd_set_master_clock_rate(uhd, srate);
}
printf("Set RX rate: %.2f MHz\n", cuhd_set_rx_srate(uhd, srate) / 1000000);
printf("Set RX gain: %.1f dB\n", cuhd_set_rx_gain(uhd, uhd_gain));
printf("Set RX freq: %.2f MHz\n", cuhd_set_rx_freq(uhd, uhd_freq) / 1000000);
cuhd_rx_wait_lo_locked(uhd);
buffer = malloc(sizeof(cf_t) * flen * 2);
if (!buffer) {
perror("malloc");
exit(-1);
}
if (srslte_pss_synch_init_fft(&pss, flen, fft_size)) {
fprintf(stderr, "Error initiating PSS\n");
exit(-1);
}
if (srslte_pss_synch_set_N_id_2(&pss, N_id_2_sync)) {
fprintf(stderr, "Error setting N_id_2=%d\n",N_id_2_sync);
exit(-1);
}
srslte_cfo_init(&cfocorr, flen);
srslte_cfo_init(&cfocorr64, flen);
if (srslte_sss_synch_init(&sss, fft_size)) {
fprintf(stderr, "Error initializing SSS object\n");
return SRSLTE_ERROR;
}
srslte_sss_synch_set_N_id_2(&sss, N_id_2);
printf("N_id_2: %d\n", N_id_2);
cuhd_start_rx_stream(uhd);
printf("Frame length %d samples\n", flen);
printf("PSS detection threshold: %.2f\n", threshold);
nof_det = nof_nodet = nof_nopeak = nof_nopeakdet = 0;
frame_cnt = 0;
last_peak = 0;
mean_peak = 0;
int peak_offset = 0;
float cfo;
float mean_cfo = 0;
uint32_t m0, m1;
uint32_t sss_error1 = 0, sss_error2 = 0, sss_error3 = 0;
uint32_t cp_is_norm = 0;
srslte_sync_t ssync;
bzero(&ssync, sizeof(srslte_sync_t));
ssync.fft_size = fft_size;
while(frame_cnt < nof_frames || nof_frames == -1) {
n = cuhd_recv(uhd, buffer, flen - peak_offset, 1);
if (n < 0) {
fprintf(stderr, "Error receiving samples\n");
exit(-1);
}
peak_idx = srslte_pss_synch_find_pss(&pss, buffer, &peak_value);
if (peak_idx < 0) {
fprintf(stderr, "Error finding PSS peak\n");
exit(-1);
}
mean_peak = SRSLTE_VEC_CMA(peak_value, mean_peak, frame_cnt);
if (peak_value >= threshold) {
nof_det++;
if (peak_idx >= fft_size) {
// Estimate CFO
cfo = srslte_pss_synch_cfo_compute(&pss, &buffer[peak_idx-fft_size]);
mean_cfo = SRSLTE_VEC_CMA(cfo, mean_cfo, frame_cnt);
// Correct CFO
srslte_cfo_correct(&cfocorr, buffer, buffer, -mean_cfo / fft_size);
// Estimate channel
if (srslte_pss_synch_chest(&pss, &buffer[peak_idx-fft_size], ce)) {
fprintf(stderr, "Error computing channel estimation\n");
exit(-1);
}
// Find SSS
int sss_idx = peak_idx-2*fft_size-(SRSLTE_CP_ISNORM(cp)?SRSLTE_CP_LEN(fft_size, SRSLTE_CP_NORM_LEN):SRSLTE_CP_LEN(fft_size, SRSLTE_CP_EXT_LEN));
if (sss_idx >= 0 && sss_idx < flen-fft_size) {
srslte_sss_synch_m0m1_partial(&sss, &buffer[sss_idx], 3, NULL, &m0, &m0_value, &m1, &m1_value);
if (srslte_sss_synch_N_id_1(&sss, m0, m1) != N_id_1) {
sss_error2++;
}
INFO("Partial N_id_1: %d\n", srslte_sss_synch_N_id_1(&sss, m0, m1));
srslte_sss_synch_m0m1_diff(&sss, &buffer[sss_idx], &m0, &m0_value, &m1, &m1_value);
if (srslte_sss_synch_N_id_1(&sss, m0, m1) != N_id_1) {
sss_error3++;
}
INFO("Diff N_id_1: %d\n", srslte_sss_synch_N_id_1(&sss, m0, m1));
srslte_sss_synch_m0m1_partial(&sss, &buffer[sss_idx], 1, NULL, &m0, &m0_value, &m1, &m1_value);
if (srslte_sss_synch_N_id_1(&sss, m0, m1) != N_id_1) {
sss_error1++;
}
INFO("Full N_id_1: %d\n", srslte_sss_synch_N_id_1(&sss, m0, m1));
}
// Estimate CP
if (peak_idx > 2*(fft_size + SRSLTE_CP_LEN_EXT(fft_size))) {
srslte_cp_t cp = srslte_sync_detect_cp(&ssync, buffer, peak_idx);
if (SRSLTE_CP_ISNORM(cp)) {
cp_is_norm++;
}
}
} else {
INFO("No space for CFO computation. Frame starts at \n",peak_idx);
}
if(srslte_sss_synch_subframe(m0,m1) == 0)
{
#ifndef DISABLE_GRAPHICS
if (!disable_plots)
do_plots_sss(sss.corr_output_m0, sss.corr_output_m1);
#endif
}
} else {
nof_nodet++;
}
if (frame_cnt > 100) {
if (abs(last_peak-peak_idx) > 4) {
if (peak_value >= threshold) {
nof_nopeakdet++;
}
nof_nopeak++;
}
}
frame_cnt++;
printf("[%5d]: Pos: %5d, PSR: %4.1f (~%4.1f) Pdet: %4.2f, "
"FA: %4.2f, CFO: %+4.1f KHz SSSmiss: %4.2f/%4.2f/%4.2f CPNorm: %.0f%%\r",
frame_cnt,
peak_idx,
peak_value, mean_peak,
(float) nof_det/frame_cnt,
(float) nof_nopeakdet/frame_cnt, mean_cfo*15,
(float) sss_error1/nof_det,(float) sss_error2/nof_det,(float) sss_error3/nof_det,
(float) cp_is_norm/nof_det * 100);
if (SRSLTE_VERBOSE_ISINFO()) {
printf("\n");
}
#ifndef DISABLE_GRAPHICS
if (!disable_plots)
do_plots(pss.conv_output_avg, pss.conv_output_avg[peak_idx], pss.fft_size+pss.frame_size-1, ce);
#endif
last_peak = peak_idx;
}
srslte_pss_synch_free(&pss);
free(buffer);
cuhd_close(uhd);
printf("Ok\n");
exit(0);
}
int main(int argc, char **argv) {
int frame_cnt, valid_frames;
int freq;
int cell_id;
sync_t sfind, strack;
float max_peak_to_avg;
float sfo;
int find_idx, track_idx, last_found;
enum sync_state state;
int n;
filesink_t fs;
if (argc < 3) {
usage(argv[0]);
exit(-1);
}
parse_args(argc,argv);
if (base_init(FLEN)) {
fprintf(stderr, "Error initializing memory\n");
exit(-1);
}
if (sync_init(&sfind, FLEN)) {
fprintf(stderr, "Error initiating PSS/SSS\n");
exit(-1);
}
sync_pss_det_peak_to_avg(&sfind);
if (sync_init(&strack, track_len)) {
fprintf(stderr, "Error initiating PSS/SSS\n");
exit(-1);
}
sync_pss_det_peak_to_avg(&strack);
nof_bands = lte_band_get_fd_band(band, channels, earfcn_start, earfcn_end, MAX_EARFCN);
printf("RSSI scan: %d freqs in band %d, RSSI threshold %.2f dBm\n", nof_bands, band, rssi_threshold);
n = rssi_scan();
if (n == -1) {
exit(-1);
}
printf("\nDone. Starting PSS search on %d channels\n", n);
usleep(500000);
INFO("Setting sampling frequency %.2f MHz\n", (float) SAMP_FREQ/MHZ);
cuhd_set_rx_srate(uhd, SAMP_FREQ);
cuhd_set_rx_gain(uhd, uhd_gain);
print_to_matlab();
filesink_init(&fs, "test.dat", COMPLEX_FLOAT_BIN);
freq=0;
state = INIT;
find_idx = 0;
max_peak_to_avg = 0;
last_found = 0;
frame_cnt = 0;
while(freq<nof_bands) {
/* scan only bands above rssi_threshold */
if (!IS_SIGNAL(freq)) {
INFO("[%3d/%d]: Skipping EARFCN %d %.2f MHz RSSI %.2f dB\n", freq, nof_bands,
channels[freq].id, channels[freq].fd,10*log10f(rssi[freq]) + 30);
freq++;
} else {
if (state == TRACK || state == FIND) {
cuhd_recv(uhd, &input_buffer[FLEN], FLEN, 1);
}
switch(state) {
case INIT:
DEBUG("Stopping receiver...\n",0);
cuhd_stop_rx_stream(uhd);
/* set freq */
cuhd_set_rx_freq(uhd, (double) channels[freq].fd * MHZ);
cuhd_rx_wait_lo_locked(uhd);
DEBUG("Set freq to %.3f MHz\n", (double) channels[freq].fd);
DEBUG("Starting receiver...\n",0);
cuhd_start_rx_stream(uhd);
/* init variables */
frame_cnt = 0;
max_peak_to_avg = -99;
cell_id = -1;
/* receive first frame */
cuhd_recv(uhd, input_buffer, FLEN, 1);
/* set find_threshold and go to FIND state */
sync_set_threshold(&sfind, find_threshold);
sync_force_N_id_2(&sfind, -1);
state = FIND;
break;
case FIND:
/* find peak in all frame */
find_idx = sync_run(&sfind, &input_buffer[FLEN]);
DEBUG("[%3d/%d]: PAR=%.2f\n", freq, nof_bands, sync_get_peak_to_avg(&sfind));
if (find_idx != -1) {
/* if found peak, go to track and set lower threshold */
frame_cnt = -1;
last_found = 0;
sync_set_threshold(&strack, track_threshold);
sync_force_N_id_2(&strack, sync_get_N_id_2(&sfind));
state = TRACK;
INFO("[%3d/%d]: EARFCN %d Freq. %.2f MHz PSS found PAR %.2f dB\n", freq, nof_bands,
channels[freq].id, channels[freq].fd,
10*log10f(sync_get_peak_to_avg(&sfind)));
} else {
if (frame_cnt >= nof_frames_find) {
state = INIT;
printf("[%3d/%d]: EARFCN %d Freq. %.2f MHz No PSS found\r", freq, nof_bands,
channels[freq].id, channels[freq].fd, frame_cnt - last_found);
if (VERBOSE_ISINFO()) {
printf("\n");
}
freq++;
}
}
break;
case TRACK:
INFO("Tracking PSS find_idx %d offset %d\n", find_idx, find_idx + track_len);
filesink_write(&fs, &input_buffer[FLEN+find_idx+track_len], track_len);
track_idx = sync_run(&strack, &input_buffer[FLEN + find_idx - track_len]);
p2a_v[frame_cnt] = sync_get_peak_to_avg(&strack);
/* save cell id for the best peak-to-avg */
if (p2a_v[frame_cnt] > max_peak_to_avg) {
max_peak_to_avg = p2a_v[frame_cnt];
cell_id = sync_get_cell_id(&strack);
}
if (track_idx != -1) {
cfo_v[frame_cnt] = sync_get_cfo(&strack);
last_found = frame_cnt;
find_idx += track_idx - track_len;
idx_v[frame_cnt] = find_idx;
} else {
idx_v[frame_cnt] = -1;
cfo_v[frame_cnt] = 0.0;
}
/* if we missed to many PSS it is not a cell, next freq */
if (frame_cnt - last_found > max_track_lost) {
INFO("\n[%3d/%d]: EARFCN %d Freq. %.2f MHz %d frames lost\n", freq, nof_bands,
channels[freq].id, channels[freq].fd, frame_cnt - last_found);
state = INIT;
freq++;
} else if (frame_cnt >= nof_frames_track) {
state = DONE;
}
break;
case DONE:
cfo[freq] = mean_valid(idx_v, cfo_v, frame_cnt);
p2a[freq] = mean_valid(idx_v, p2a_v, frame_cnt);
valid_frames = preprocess_idx(idx_v, idx_valid, t, frame_cnt);
sfo = sfo_estimate_period(idx_valid, t, valid_frames, FLEN_PERIOD);
printf("\n[%3d/%d]: FOUND EARFCN %d Freq. %.2f MHz. "
"PAR %2.2f dB, CFO=%+.2f KHz, SFO=%+2.3f KHz, CELL_ID=%3d\n", freq, nof_bands,
channels[freq].id, channels[freq].fd,
10*log10f(p2a[freq]), cfo[freq] * 15, sfo / 1000, cell_id);
state = INIT;
freq++;
break;
}
if (state == TRACK || (state == FIND && frame_cnt)) {
memcpy(input_buffer, &input_buffer[FLEN], FLEN * sizeof(cf_t));
}
frame_cnt++;
}
}
print_to_matlab();
sync_free(&sfind);
base_free();
printf("\n\nDone\n");
exit(0);
}
