Exemple #1
0
int base_init() {
  int i;

  if (filesource_init(&fsrc, input_file_name, COMPLEX_FLOAT_BIN)) {
    fprintf(stderr, "Error opening file %s\n", input_file_name);
    exit(-1);
  }

  flen = 2 * (SLOT_LEN(lte_symbol_sz(cell.nof_prb)));

  input_buffer = malloc(flen * sizeof(cf_t));
  if (!input_buffer) {
    perror("malloc");
    exit(-1);
  }

  fft_buffer = malloc(SF_LEN_RE(cell.nof_prb, cell.cp) * sizeof(cf_t));
  if (!fft_buffer) {
    perror("malloc");
    return -1;
  }

  for (i=0;i<MAX_PORTS;i++) {
    ce[i] = malloc(SF_LEN_RE(cell.nof_prb, cell.cp) * sizeof(cf_t));
    if (!ce[i]) {
      perror("malloc");
      return -1;
    }
  }

  if (chest_dl_init(&chest, cell)) {
    fprintf(stderr, "Error initializing equalizer\n");
    return -1;
  }

  if (lte_fft_init(&fft, cell.cp, cell.nof_prb)) {
    fprintf(stderr, "Error initializing FFT\n");
    return -1;
  }

  if (regs_init(&regs, cell)) {
    fprintf(stderr, "Error initiating regs\n");
    return -1;
  }

  if (regs_set_cfi(&regs, cfi)) {
    fprintf(stderr, "Error setting CFI %d\n", cfi);
    return -1;
  }
  if (pdcch_init(&pdcch, &regs, cell)) {
    fprintf(stderr, "Error creating PDCCH object\n");
    exit(-1);
  }
  
  DEBUG("Memory init OK\n",0);
  return 0;
}
Exemple #2
0
int main(int argc, char **argv) {
  int nf, sf_idx, N_id_2;
  cf_t pss_signal[PSS_LEN];
  float sss_signal0[SSS_LEN]; // for subframe 0
  float sss_signal5[SSS_LEN]; // for subframe 5
  pbch_mib_t mib;
  ra_pdsch_t ra_dl;
  ra_prb_t prb_alloc;
  refsignal_t refs[NSLOTS_X_FRAME];
  int i, n;
  char *data;
  cf_t *sf_symbols[MAX_PORTS];
  dci_msg_t dci_msg;
  dci_location_t locations[NSUBFRAMES_X_FRAME][10];

#ifdef DISABLE_UHD
  if (argc < 3) {
    usage(argv[0]);
    exit(-1);
  }
#endif

  parse_args(argc, argv);

  N_id_2 = cell.id % 3;
  sf_n_re = 2 * CPNORM_NSYMB * cell.nof_prb * RE_X_RB;
  sf_n_samples = 2 * SLOT_LEN(lte_symbol_sz(cell.nof_prb));

  /* this *must* be called after setting slot_len_* */
  base_init();

  /* Generate PSS/SSS signals */
  pss_generate(pss_signal, N_id_2);
  sss_generate(sss_signal0, sss_signal5, cell.id);
  
  /* Generate CRS signals */
  for (i = 0; i < NSLOTS_X_FRAME; i++) {
    if (refsignal_init_LTEDL(&refs[i], 0, i, cell)) {
      fprintf(stderr, "Error initiating CRS slot=%d\n", i);
      return -1;
    }
  }

  mib.nof_ports = cell.nof_ports;
  mib.nof_prb = cell.nof_prb;
  mib.phich_length = PHICH_NORM;
  mib.phich_resources = R_1;
  mib.sfn = 0;

  for (i = 0; i < MAX_PORTS; i++) { // now there's only 1 port
    sf_symbols[i] = sf_buffer;
  }

#ifndef DISABLE_UHD
  if (!output_file_name) {
    printf("Set TX rate: %.2f MHz\n",
        cuhd_set_tx_srate(uhd, lte_sampling_freq_hz(cell.nof_prb)) / 1000000);
    printf("Set TX gain: %.1f dB\n", cuhd_set_tx_gain(uhd, uhd_gain));
    printf("Set TX freq: %.2f MHz\n",
        cuhd_set_tx_freq(uhd, uhd_freq) / 1000000);
  }
#endif

  bzero(&ra_dl, sizeof(ra_pdsch_t));
  ra_dl.harq_process = 0;
  ra_dl.mcs_idx = mcs_idx;
  ra_dl.ndi = 0;
  ra_dl.rv_idx = 0;
  ra_dl.alloc_type = alloc_type0;
  ra_dl.type0_alloc.rbg_bitmask = 0xffffffff;
  
  dci_msg_pack_pdsch(&ra_dl, &dci_msg, Format1, cell.nof_prb, false);
  
  ra_prb_get_dl(&prb_alloc, &ra_dl, cell.nof_prb);
  ra_prb_get_re_dl(&prb_alloc, cell.nof_prb, 1, cell.nof_prb<10?(cfi+1):cfi, CPNORM);
  ra_mcs_from_idx_dl(mcs_idx, cell.nof_prb, &ra_dl.mcs);

  ra_pdsch_fprint(stdout, &ra_dl, cell.nof_prb);
  
  /* Initiate valid DCI locations */
  for (i=0;i<NSUBFRAMES_X_FRAME;i++) {
    pdcch_ue_locations(&pdcch, locations[i], 10, i, cfi, 1234);
  }

  data = malloc(sizeof(char) * ra_dl.mcs.tbs);
  if (!data) {
    perror("malloc");
    exit(-1);
  }  
    
  nf = 0;
  
  if (pdsch_harq_setup(&harq_process, ra_dl.mcs, &prb_alloc)) {
    fprintf(stderr, "Error configuring HARQ process\n");
    exit(-1);
  }

  while (nf < nof_frames || nof_frames == -1) {
    for (sf_idx = 0; sf_idx < NSUBFRAMES_X_FRAME && (nf < nof_frames || nof_frames == -1); sf_idx++) {
      bzero(sf_buffer, sizeof(cf_t) * sf_n_re);

      if (sf_idx == 0 || sf_idx == 5) {
        pss_put_slot(pss_signal, sf_buffer, cell.nof_prb, CPNORM);
        sss_put_slot(sf_idx ? sss_signal5 : sss_signal0, sf_buffer, cell.nof_prb,
            CPNORM);
      }
      
      if (sf_idx == 0) {
        pbch_encode(&pbch, &mib, sf_symbols);
      }
    
      for (n=0;n<2;n++) {
        refsignal_put(&refs[2*sf_idx+n], &sf_buffer[n*sf_n_re/2]);
      }

      pcfich_encode(&pcfich, cfi, sf_symbols, sf_idx);       

      INFO("SF: %d, Generating %d random bits\n", sf_idx, ra_dl.mcs.tbs);
      for (i=0;i<ra_dl.mcs.tbs;i++) {
        data[i] = rand()%2;
      }
      
      INFO("Puttting DCI to location: n=%d, L=%d\n", locations[sf_idx][0].ncce, locations[sf_idx][0].L);
      if (pdcch_encode(&pdcch, &dci_msg, locations[sf_idx][0], 1234, sf_symbols, sf_idx, cfi)) {
        fprintf(stderr, "Error encoding DCI message\n");
        exit(-1);
      }
      
      if (pdsch_encode(&pdsch, data, sf_symbols, sf_idx, &harq_process, ra_dl.rv_idx)) {
        fprintf(stderr, "Error encoding PDSCH\n");
        exit(-1);
      }

      /* Transform to OFDM symbols */
      lte_ifft_run_sf(&ifft, sf_buffer, output_buffer);
      
      /* send to file or usrp */
      if (output_file_name) {
        filesink_write(&fsink, output_buffer, sf_n_samples);
        usleep(5000);
      } else {
#ifndef DISABLE_UHD
        vec_sc_prod_cfc(output_buffer, uhd_amp, output_buffer, sf_n_samples);
        cuhd_send(uhd, output_buffer, sf_n_samples, true);
#endif
      }
      nf++;
    }
    mib.sfn = (mib.sfn + 1) % 1024;
    printf("SFN: %4d\r", mib.sfn);
    fflush(stdout);
  }

  base_free();

  printf("Done\n");
  exit(0);
}
Exemple #3
0
int main(int argc, char **argv) {
  cf_t *input_buffer, *sf_symbols = NULL; 
  int frame_cnt;
  ue_sync_t s; 
  int pos;
  pss_synch_t pss; 
  float peak;
  struct timeval t[3];
  float mean_ce_time=0;
  bool signal_detected; 
  lte_fft_t fft; 
  lte_cell_t cell; 
  
  bzero(&cell, sizeof(lte_cell_t));
  
  parse_args(argc, argv);
    
  #ifndef DISABLE_GRAPHICS
  if (!disable_plots) {
    init_plots();    
  }
  #endif
  
  input_init();
        
  if (ue_sync_init(&s, cuhd_set_rx_srate, cuhd_recv_wrapper, uhd)) {
    fprintf(stderr, "Error initiating UE sync module\n");
    exit(-1);
  }
  
  ue_sync_pbch_enable(&s, true);
  
  signal_detected = true;
  frame_cnt = 0;
  mean_ce_time=0;
  uint32_t valid_frames=0;
  //uint32_t unaligned = 0; 
  while (frame_cnt < nof_frames || nof_frames == -1) {    

    int n = ue_sync_get_buffer(&s, &input_buffer);
    if (n < 0) {
      fprintf(stderr, "Error calling sync work()\n");
      exit(-1);      
    }
    
    if (n == 1 && ue_sync_get_sfidx(&s) == 0) {

      if (signal_detected) {
        cell = ue_sync_get_cell(&s);
        pss_synch_init_fft(&pss, 
                          SF_LEN(lte_symbol_sz(cell.nof_prb), cell.cp), 
                          lte_symbol_sz(cell.nof_prb));
        pss_synch_set_N_id_2(&pss, cell.id%3);
        
        sf_symbols = vec_malloc(SLOT_LEN_RE(cell.nof_prb, cell.cp) * sizeof(cf_t));
        if (!sf_symbols) {
          perror("malloc");
          exit(-1);
        }
        lte_fft_init(&fft, cell.cp, cell.nof_prb);
        signal_detected = false; 
      }
      
      mean_ce_time = (float) (mean_ce_time + (float) t[0].tv_usec * valid_frames) / (valid_frames+1);
      valid_frames++;
      
      #ifndef DISABLE_GRAPHICS
      if (!disable_plots && !(valid_frames % 5) && sf_symbols) {
        
        /* Run FFT for the second slot */
        lte_fft_run_slot(&fft, input_buffer, sf_symbols);
    
        int i;
        int nof_re = SLOT_LEN_RE(cell.nof_prb, cell.cp);
        for (i = 0; i < nof_re; i++) {
          tmp_plot[i] = 10 * log10f(cabsf(sf_symbols[i]));
          if (isinf(tmp_plot[i])) {
            tmp_plot[i] = -80;
          }
        }
        plot_real_setNewData(&poutfft, tmp_plot, nof_re);        
      }
    #endif
      
      pos = pss_synch_find_pss(&pss, input_buffer, &peak, NULL);      
      /*if (pos > 962 || pos < 958) {
        unaligned++;
      }
      */
      printf("CELL_ID: %3d CFO: %+.4f KHz, SFO: %+.4f Khz, TimeOffset: %4d, Exec: %3.2f\r",
              cell.id, ue_sync_get_cfo(&s)/1000, ue_sync_get_sfo(&s)/1000, pos, 
             s.mean_exec_time);
          fflush(stdout);
      if (VERBOSE_ISINFO()) {
        printf("\n");
      }
    }
      
    frame_cnt++;
  }

  printf("\nBye\n");
  exit(0);
}
Exemple #4
0
int base_init() {
  int i;
  
  if (filesource_init(&fsrc, input_file_name, COMPLEX_FLOAT_BIN)) {
    fprintf(stderr, "Error opening file %s\n", input_file_name);
    exit(-1);
  }

  if (matlab_file_name) {
    fmatlab = fopen(matlab_file_name, "w");
    if (!fmatlab) {
      perror("fopen");
      return -1;
    }
  } else {
    fmatlab = NULL;
  }

  flen = SLOT_LEN(lte_symbol_sz(cell.nof_prb));

  input_buffer = malloc(flen * sizeof(cf_t));
  if (!input_buffer) {
    perror("malloc");
    exit(-1);
  }

  fft_buffer = malloc(SF_LEN_RE(cell.nof_prb, cell.cp) * sizeof(cf_t));
  if (!fft_buffer) {
    perror("malloc");
    return -1;
  }

  for (i=0;i<MAX_PORTS;i++) {
    ce[i] = malloc(SF_LEN_RE(cell.nof_prb, cell.cp) * sizeof(cf_t));
    if (!ce[i]) {
      perror("malloc");
      return -1;
    }
  }
  
  if (chest_dl_init(&chest, cell)) {
    fprintf(stderr, "Error initializing equalizer\n");
    return -1;
  }

  if (lte_fft_init(&fft, cell.cp, cell.nof_prb)) {
    fprintf(stderr, "Error initializing FFT\n");
    return -1;
  }

  if (regs_init(&regs, cell)) {
    fprintf(stderr, "Error initiating REGs\n");
    return -1;
  }

  if (pcfich_init(&pcfich, &regs, cell)) {
    fprintf(stderr, "Error creating PBCH object\n");
    return -1;
  }

  DEBUG("Memory init OK\n",0);
  return 0;
}
Exemple #5
0
int main(int argc, char **argv) {
	int nf, ns, N_id_2;
	cf_t pss_signal[PSS_LEN];
	float sss_signal0[SSS_LEN]; // for subframe 0
	float sss_signal5[SSS_LEN]; // for subframe 5
	pbch_mib_t mib;
	refsignal_t refs[NSLOTS_X_FRAME];
	int i;
	cf_t *slot1_symbols[MAX_PORTS_CTRL];


#ifdef DISABLE_UHD
	if (argc < 3) {
		usage(argv[0]);
		exit(-1);
	}
#endif

	parse_args(argc,argv);

	N_id_2 = cell_id%3;
	slot_n_re = CPNORM_NSYMB * nof_prb * RE_X_RB;
	slot_n_samples = SLOT_LEN_CPNORM(lte_symbol_sz(nof_prb));

	/* this *must* be called after setting slot_len_* */
	base_init();

	/* Generate PSS/SSS signals */
	pss_generate(pss_signal, N_id_2);
	sss_generate(sss_signal0, sss_signal5, cell_id);

	/* Generate CRS signals */
	for (i=0;i<NSLOTS_X_FRAME;i++) {
		if (refsignal_init_LTEDL(&refs[i], 0, i, cell_id, CPNORM, nof_prb)) {
			fprintf(stderr, "Error initiating CRS slot=%d\n", i);
			return -1;
		}
	}

	mib.nof_ports = 1;
	mib.nof_prb = 6;
	mib.phich_length = PHICH_NORM;
	mib.phich_resources = R_1;
	mib.sfn = 0;

	for (i=0;i<MAX_PORTS_CTRL;i++) { // now there's only 1 port
		slot1_symbols[i] = slot_buffer;
	}

#ifndef DISABLE_UHD
	if (!output_file_name) {
		printf("Set TX rate: %.2f MHz\n", cuhd_set_tx_srate(uhd, UHD_SAMP_FREQ)/1000000);
		printf("Set TX gain: %.1f dB\n", cuhd_set_tx_gain(uhd, uhd_gain));
		printf("Set TX freq: %.2f MHz\n", cuhd_set_tx_freq(uhd, uhd_freq)/1000000);
	}
#endif

	nf = 0;

	while(nf<nof_frames || nof_frames == -1) {
		for (ns=0;ns<NSLOTS_X_FRAME;ns++) {
			bzero(slot_buffer, sizeof(cf_t) * slot_n_re);

			switch(ns) {
			case 0: // tx pss/sss
			case 10: // tx pss/sss
				pss_put_slot(pss_signal, slot_buffer, nof_prb, CPNORM);
				sss_put_slot(ns?sss_signal5:sss_signal0, slot_buffer, nof_prb, CPNORM);
				break;
			case 1: // tx pbch
				pbch_encode(&pbch, &mib, slot1_symbols, 1);
				break;
			default: // transmit zeros
				break;
			}

			refsignal_put(&refs[ns], slot_buffer);

			/* Transform to OFDM symbols */
			lte_ifft_run(&ifft, slot_buffer, output_buffer);

			/* send to file or usrp */
			if (output_file_name) {
				filesink_write(&fsink, output_buffer, slot_n_samples);
				usleep(5000);
			} else {
#ifndef DISABLE_UHD
				vec_sc_prod_cfc(output_buffer, uhd_amp, output_buffer, slot_n_samples);
				cuhd_send(uhd, output_buffer, slot_n_samples, 1);
#endif
			}
		}
		mib.sfn=(mib.sfn+1)%1024;
		printf("SFN: %4d\r", mib.sfn);fflush(stdout);
		nf++;
	}

	base_free();

	printf("Done\n");
	exit(0);
}
Exemple #6
0
int base_init() {
  int i;

  if (filesource_init(&fsrc, input_file_name, COMPLEX_FLOAT_BIN)) {
    fprintf(stderr, "Error opening file %s\n", input_file_name);
    exit(-1);
  }

  if (matlab_file_name) {
    fmatlab = fopen(matlab_file_name, "w");
    if (!fmatlab) {
      perror("fopen");
      return -1;
    }
  } else {
    fmatlab = NULL;
  }

  flen = 2 * (SLOT_LEN(lte_symbol_sz(cell.nof_prb)));

  input_buffer = malloc(flen * sizeof(cf_t));
  if (!input_buffer) {
    perror("malloc");
    exit(-1);
  }

  fft_buffer = malloc(2 * CP_NSYMB(cell.cp) * cell.nof_prb * RE_X_RB * sizeof(cf_t));
  if (!fft_buffer) {
    perror("malloc");
    return -1;
  }

  for (i=0;i<MAX_PORTS;i++) {
    ce[i] = malloc(2 * CP_NSYMB(cell.cp) * cell.nof_prb * RE_X_RB * sizeof(cf_t));
    if (!ce[i]) {
      perror("malloc");
      return -1;
    }
  }

  if (chest_init_LTEDL(&chest, cell)) {
    fprintf(stderr, "Error initializing equalizer\n");
    return -1;
  }

  if (lte_fft_init(&fft, cell.cp, cell.nof_prb)) {
    fprintf(stderr, "Error initializing FFT\n");
    return -1;
  }

  if (regs_init(&regs, R_1, PHICH_NORM, cell)) {
    fprintf(stderr, "Error initiating regs\n");
    return -1;
  }

  if (regs_set_cfi(&regs, cfi)) {
    fprintf(stderr, "Error setting CFI %d\n", cfi);
    return -1;
  }

  if (pdcch_init(&pdcch, &regs, cell)) {
    fprintf(stderr, "Error creating PDCCH object\n");
    exit(-1);
  }

  if (pdsch_init(&pdsch, cell)) {
    fprintf(stderr, "Error creating PDSCH object\n");
    exit(-1);
  }
  pdsch_set_rnti(&pdsch, rnti);
  
  if (pdsch_harq_init(&harq_process, &pdsch)) {
    fprintf(stderr, "Error initiating HARQ process\n");
    exit(-1);
  }

  DEBUG("Memory init OK\n",0);
  return 0;
}
int base_init() {
	int i;

	if (filesource_init(&fsrc, input_file_name, COMPLEX_FLOAT_BIN)) {
		fprintf(stderr, "Error opening file %s\n", input_file_name);
		exit(-1);
	}

	if (matlab_file_name) {
		fmatlab = fopen(matlab_file_name, "w");
		if (!fmatlab) {
			perror("fopen");
			return -1;
		}
	} else {
		fmatlab = NULL;
	}

	flen = SLOT_LEN(lte_symbol_sz(nof_prb), cp);

	input_buffer = malloc(flen * sizeof(cf_t));
	if (!input_buffer) {
		perror("malloc");
		exit(-1);
	}

	fft_buffer = malloc(CP_NSYMB(cp) * nof_prb * RE_X_RB * sizeof(cf_t));
	if (!fft_buffer) {
		perror("malloc");
		return -1;
	}

	for (i=0;i<MAX_PORTS_CTRL;i++) {
		ce[i] = malloc(CP_NSYMB(cp) * nof_prb * RE_X_RB * sizeof(cf_t));
		if (!ce[i]) {
			perror("malloc");
			return -1;
		}
	}

	if (chest_init(&chest, LINEAR, cp, nof_prb, nof_ports)) {
		fprintf(stderr, "Error initializing equalizer\n");
		return -1;
	}

	if (chest_ref_LTEDL(&chest, cell_id)) {
		fprintf(stderr, "Error initializing reference signal\n");
		return -1;
	}

	if (lte_fft_init(&fft, cp, nof_prb)) {
		fprintf(stderr, "Error initializing FFT\n");
		return -1;
	}

	if (regs_init(&regs, cell_id, nof_prb, nof_ports, phich_res, phich_length, cp)) {
		fprintf(stderr, "Error initiating regs\n");
		return -1;
	}

	if (phich_init(&phich, &regs, cell_id, nof_prb, nof_ports, cp)) {
		fprintf(stderr, "Error creating PBCH object\n");
		return -1;
	}

	DEBUG("Memory init OK\n",0);
	return 0;
}
Exemple #8
0
/* Setup USRP or input file */
int iodev_init(iodev_t *q, iodev_cfg_t *config, lte_cell_t *cell, pbch_mib_t *mib) {
  
  if (config->input_file_name) {
    
    mib->phich_resources = R_1; 
    mib->phich_length = PHICH_NORM;
    
    cell->id = config->cell_id_file;
    cell->cp = CPNORM; 
    cell->nof_ports = config->nof_ports_file; 
    cell->nof_prb = config->nof_prb_file; 

    if (filesource_init(&q->fsrc, config->input_file_name, COMPLEX_FLOAT_BIN)) {
      return LIBLTE_ERROR;
    }
    q->mode = FILESOURCE;
    int symbol_sz = lte_symbol_sz(cell->nof_prb);
    if (symbol_sz > 0) {
      q->sf_len = SF_LEN(symbol_sz);      
    } else {
      fprintf(stderr, "Invalid number of PRB %d\n", cell->nof_prb);
      return LIBLTE_ERROR; 
    }

    q->input_buffer_file = vec_malloc(q->sf_len * sizeof(cf_t));
    if (!q->input_buffer_file) {
      perror("malloc");
      return LIBLTE_ERROR; 
    }
    q->sf_idx = 9; 
    
  } else {
#ifndef DISABLE_UHD
    printf("Opening UHD device...\n");
    if (cuhd_open(config->uhd_args, &q->uhd)) {
      fprintf(stderr, "Error opening uhd\n");
      return LIBLTE_ERROR;
    }
    
    cuhd_set_rx_gain(q->uhd, config->uhd_gain);

    /* set receiver frequency */
    cuhd_set_rx_freq(q->uhd, (double) config->uhd_freq);

    cuhd_rx_wait_lo_locked(q->uhd);
    DEBUG("Set uhd_freq to %.3f MHz\n", (double ) config->uhd_freq);

    int n; 
    ue_celldetect_t cd;
    ue_celldetect_result_t found_cells[3];

    cf_t *buffer = vec_malloc(sizeof(cf_t) * 96000);
    if (!buffer) {
      perror("malloc");
      return LIBLTE_ERROR;
    }
    if (ue_celldetect_init(&cd)) {
      fprintf(stderr, "Error initiating UE cell detect\n");
      exit(-1);
    }
    n = find_cell(q->uhd, &cd, buffer, found_cells);
    if (n < 0) {
      fprintf(stderr, "Error searching cell\n");
      exit(-1);
    }

    int max_peak_cell = 0;
    float max_peak_value = -1.0;
    if (n > 0) {
      for (int i=0;i<3;i++) {
        if (found_cells[i].peak > max_peak_value) {
          max_peak_value = found_cells[i].peak;
          max_peak_cell = i;
        }
      }
      if (decode_pbch(q->uhd, buffer, &found_cells[max_peak_cell], 400, mib)) {
        fprintf(stderr, "Could not decode PBCH from CELL ID %d\n", found_cells[max_peak_cell].cell_id);
        return LIBLTE_ERROR;
      }
    } else {
      fprintf(stderr, "Could not find any cell in this frequency\n");
      return LIBLTE_ERROR;
    }
    
    free(buffer);
    cell->cp = found_cells[max_peak_cell].cp;
    cell->id = found_cells[max_peak_cell].cell_id;
    cell->nof_prb = mib->nof_prb;
    cell->nof_ports = mib->nof_ports; 
    
    /* set sampling frequency */
    int srate = lte_sampling_freq_hz(cell->nof_prb);
    if (srate != -1) {  
      cuhd_set_rx_srate(q->uhd, (double) srate);      
    } else {
      fprintf(stderr, "Invalid number of PRB %d\n", cell->nof_prb);
      return LIBLTE_ERROR;
    }

    DEBUG("Starting receiver...\n", 0);
    cuhd_start_rx_stream(q->uhd);
    
    if (ue_sync_init(&q->sframe, *cell, cuhd_recv_wrapper, q->uhd)) {
      fprintf(stderr, "Error initiating ue_sync\n");
      return LIBLTE_ERROR; 
    }

    /* Decodes the SSS signal during the tracking phase. Extra overhead, but makes sure we are in the correct subframe */  
    ue_sync_decode_sss_on_track(&q->sframe, true);

    // Here, the subframe length and input buffer is managed by ue_sync
    q->mode = UHD; 
  
#else
    printf("Error UHD not available. Select an input file\n");
    return LIBLTE_ERROR;
#endif
  }
  
  memcpy(&q->config, config, sizeof(iodev_cfg_t));
  
  return LIBLTE_SUCCESS;
}