srsLTE/srslte/examples/usrp_txrx.c

/**
 *
 * \section COPYRIGHT
 *
 * Copyright 2013-2015 The srsLTE Developers. See the
 * COPYRIGHT file at the top-level directory of this distribution.
 *
 * \section LICENSE
 *
 * This file is part of the srsLTE library.
 *
 * srsLTE is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as
 * published by the Free Software Foundation, either version 3 of
 * the License, or (at your option) any later version.
 *
 * srsLTE is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * A copy of the GNU Affero General Public License can be found in
 * the LICENSE file in the top-level directory of this distribution
 * and at http://www.gnu.org/licenses/.
 *
 */


#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <math.h>
#include <time.h>
#include <complex.h>

#include "srslte/cuhd/cuhd.h"
#include "srslte/srslte.h"

uint32_t nof_prb          = 25;
uint32_t nof_frames = 20; 

float uhd_rx_gain=40, uhd_tx_gain=40, uhd_freq=2.4e9; 
char *uhd_args="";
char *output_filename = NULL;
char *input_filename = NULL;

void usage(char *prog) {
  printf("Usage: %s -i [tx_signal_file] -o [rx_signal_file]\n", prog);
  printf("\t-a UHD args [Default %s]\n", uhd_args);
  printf("\t-f UHD TX/RX frequency [Default %.2f MHz]\n", uhd_freq/1e6);
  printf("\t-g UHD RX gain [Default %.1f dB]\n", uhd_rx_gain);
  printf("\t-G UHD TX gain [Default %.1f dB]\n", uhd_tx_gain);
  printf("\t-p Number of UL RB [Default %d]\n", nof_prb);  
}

void parse_args(int argc, char **argv) {
  int opt;
  while ((opt = getopt(argc, argv, "ioafgp")) != -1) {
    switch (opt) {
    case 'a':
      uhd_args = argv[optind];
      break;
    case 'o':
      output_filename = argv[optind];
      break;
    case 'i':
      input_filename = argv[optind];
      break;
    case 'f':
      uhd_freq = atof(argv[optind]);
      break;
    case 'g':
      uhd_rx_gain = atof(argv[optind]);
      break;
    case 'G':
      uhd_tx_gain = atof(argv[optind]);
      break;
    case 'p':
      nof_prb = atoi(argv[optind]);
      if (!srslte_nofprb_isvalid(nof_prb)) {
        fprintf(stderr, "Invalid number of UL RB %d\n", nof_prb);
        exit(-1);
      }
      break;
    default:
      usage(argv[0]);
      exit(-1);
    }
  }
  if (!input_filename || !output_filename) {
    usage(argv[0]);
    exit(-1);
  }
}

int main(int argc, char **argv) {
  parse_args(argc, argv);
  
  uint32_t flen = srslte_sampling_freq_hz(nof_prb)/1000;

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

  cf_t *tx_buffer = malloc(sizeof(cf_t)*flen);
  if (!tx_buffer) {
    perror("malloc");
    exit(-1);
  }
  cf_t *zeros = calloc(sizeof(cf_t),flen);
  if (!zeros) {
    perror("calloc");
    exit(-1);
  }
 
  // Send through UHD 
  void *uhd; 
  printf("Opening UHD device...\n");
  if (cuhd_open(uhd_args, &uhd)) {
    fprintf(stderr, "Error opening uhd\n");
    exit(-1);
  }
  printf("Subframe len:   %d samples\n", flen);
  printf("Set TX/RX rate: %.2f MHz\n", cuhd_set_rx_srate(uhd, srslte_sampling_freq_hz(nof_prb)) / 1000000);
  printf("Set RX gain: %.1f dB\n", cuhd_set_rx_gain(uhd, uhd_rx_gain));
  printf("Set TX gain: %.1f dB\n", cuhd_set_tx_gain(uhd, uhd_tx_gain));
  printf("Set TX/RX freq: %.2f MHz\n", cuhd_set_rx_freq(uhd, uhd_freq) / 1000000);
  cuhd_set_tx_srate(uhd, srslte_sampling_freq_hz(nof_prb));
  cuhd_set_tx_freq_offset(uhd, uhd_freq, 8e6);  
  sleep(1);
  
  srslte_vec_load_file(input_filename, tx_buffer, flen*sizeof(cf_t));

  srslte_timestamp_t tstamp; 
  
  cuhd_start_rx_stream(uhd);
  uint32_t nframe=0;
  
  while(nframe<nof_frames) {
    printf("Rx subframe %d\n", nframe);
    cuhd_recv_with_time(uhd, &rx_buffer[flen*nframe], flen, true, &tstamp.full_secs, &tstamp.frac_secs);
    nframe++;
    if (nframe==9 || nframe==8) {
      srslte_timestamp_add(&tstamp, 0, 2e-3);
      if (nframe==8) {
        cuhd_send_timed2(uhd, zeros, flen, tstamp.full_secs, tstamp.frac_secs, true, false);      
        printf("Transmitting zeros\n");        
      } else {
        cuhd_send_timed2(uhd, tx_buffer, flen, tstamp.full_secs, tstamp.frac_secs, false, true);      
        printf("Transmitting Signal\n");  
      }
    }

  }

  srslte_vec_save_file(output_filename, &rx_buffer[10*flen], flen*sizeof(cf_t));

  free(tx_buffer);
  free(rx_buffer);

  printf("Done\n");
  exit(0);
}