Added cell measurement example

lte/phy/examples/cell_measurement.c

@@ -0,0 +1,218 @@
+/**
+ *
+ * \section COPYRIGHT
+ *
+ * Copyright 2013-2014 The libLTE Developers. See the
+ * COPYRIGHT file at the top-level directory of this distribution.
+ *
+ * \section LICENSE
+ *
+ * This file is part of the libLTE library.
+ *
+ * libLTE is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as
+ * published by the Free Software Foundation, either version 3 of
+ * the License, or (at your option) any later version.
+ *
+ * libLTE 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 Lesser General Public License for more details.
+ *
+ * A copy of the GNU Lesser 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 <strings.h>
+#include <unistd.h>
+#include <math.h>
+#include <sys/time.h>
+#include <unistd.h>
+#include <assert.h>
+#include <signal.h>
+
+#include "liblte/phy/phy.h"
+#include "liblte/cuhd/cuhd.h"
+#include "cell_search_utils.h"
+
+/**********************************************************************
+ *  Program arguments processing
+ ***********************************************************************/
+typedef struct {
+  int nof_subframes;
+  bool disable_plots;
+  int force_N_id_2;
+  char *uhd_args; 
+  float uhd_freq; 
+  float uhd_gain;
+}prog_args_t;
+
+void args_default(prog_args_t *args) {
+  args->nof_subframes = -1; 
+  args->force_N_id_2 = -1; // Pick the best
+  args->uhd_args = "";
+  args->uhd_freq = -1.0;
+  args->uhd_gain = 60.0; 
+}
+
+void usage(prog_args_t *args, char *prog) {
+  printf("Usage: %s [aglnv] -f rx_frequency (in Hz)\n", prog);
+  printf("\t-a UHD args [Default %s]\n", args->uhd_args);
+  printf("\t-g UHD RX gain [Default %.2f dB]\n", args->uhd_gain);
+  printf("\t-l Force N_id_2 [Default best]\n");
+  printf("\t-n nof_subframes [Default %d]\n", args->nof_subframes);
+  printf("\t-v [set verbose to debug, default none]\n");
+}
+
+void parse_args(prog_args_t *args, int argc, char **argv) {
+  int opt;
+  args_default(args);
+  while ((opt = getopt(argc, argv, "aglnvf")) != -1) {
+    switch (opt) {
+    case 'a':
+      args->uhd_args = argv[optind];
+      break;
+    case 'g':
+      args->uhd_gain = atof(argv[optind]);
+      break;
+    case 'f':
+      args->uhd_freq = atof(argv[optind]);
+      break;
+    case 'n':
+      args->nof_subframes = atoi(argv[optind]);
+      break;
+    case 'l':
+      args->force_N_id_2 = atoi(argv[optind]);
+      break;
+    case 'v':
+      verbose++;
+      break;
+    default:
+      usage(args, argv[0]);
+      exit(-1);
+    }
+  }
+  if (args->uhd_freq < 0) {
+    usage(args, argv[0]);
+    exit(-1);
+  }
+}
+/**********************************************************************/
+
+/* TODO: Do something with the output data */
+char data[10000];
+
+int cuhd_recv_wrapper(void *h, void *data, uint32_t nsamples) {
+  DEBUG(" ----  Receive %d samples  ---- \n", nsamples);
+  return cuhd_recv(h, data, nsamples, 1);
+}
+
+
+int main(int argc, char **argv) {
+  int ret; 
+  cf_t *sf_buffer; 
+  prog_args_t prog_args; 
+  lte_cell_t cell;  
+  int64_t sf_cnt;
+  pbch_mib_t mib;
+  ue_sync_t ue_sync; 
+  void *uhd; 
+  
+  parse_args(&prog_args, argc, argv);
+
+  printf("Opening UHD device...\n");
+  if (cuhd_open(prog_args.uhd_args, &uhd)) {
+    fprintf(stderr, "Error opening uhd\n");
+    exit(-1);
+  }
+  /* Set receiver gain */
+  cuhd_set_rx_gain(uhd, prog_args.uhd_gain);
+
+  /* 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);
+
+  if (cell_search(uhd, prog_args.force_N_id_2, &cell, &mib)) {
+    fprintf(stderr, "Cell not found\n");
+    exit(-1); 
+  }
+  
+  cuhd_start_rx_stream(uhd);
+  
+  if (ue_sync_init(&ue_sync, cell, cuhd_recv_wrapper, uhd)) {
+    fprintf(stderr, "Error initiating ue_sync\n");
+    exit(-1); 
+  }
+  
+  /* Initialize subframe counter */
+  sf_cnt = 0;
+    
+  lte_fft_t fft; 
+  chest_t chest; 
+  
+  if (lte_fft_init(&fft, cell.cp, cell.nof_prb)) {
+    fprintf(stderr, "Error initiating FFT\n");
+    return -1;
+  }
+  if (chest_init_LTEDL(&chest, cell)) {
+    fprintf(stderr, "Error initiating channel estimator\n");
+    return -1;
+  }
+  
+  int sf_re = SF_LEN_RE(cell.nof_prb, cell.cp);
+  cf_t *sf_symbols = vec_malloc(sf_re * sizeof(cf_t));
+  unsigned int nframes=0;
+  
+  /* Main loop */
+  while (sf_cnt < prog_args.nof_subframes || prog_args.nof_subframes == -1) {
+    
+    ret = ue_sync_get_buffer(&ue_sync, &sf_buffer);
+    if (ret < 0) {
+      fprintf(stderr, "Error calling ue_sync_work()\n");
+    }
+    
+    float rssi=0, rsrp=0, rsrq=0;
+    
+    /* iodev_receive returns 1 if successfully read 1 aligned subframe */
+    if (ret == 1) {
+
+      /* Run FFT for all subframe data */
+      lte_fft_run_sf(&fft, sf_buffer, sf_symbols);
+
+      chest_measure_sf(&chest, sf_symbols, ue_sync_get_sfidx(&ue_sync));
+      rssi = VEC_CMA(chest_rssi_sf(&chest, sf_symbols),rssi,nframes);
+      rsrq = VEC_CMA(chest_rsrq_sf(&chest, sf_symbols, ue_sync_get_sfidx(&ue_sync)),rsrq,nframes);
+      rsrp = VEC_CMA(chest_rsrp_sf(&chest, ue_sync_get_sfidx(&ue_sync)),rsrp,nframes);      
+      nframes++;
+      
+      // Plot and Printf
+      if ((nframes%10) == 0) {
+        printf("CFO: %+6.4f KHz, SFO: %+6.4f Khz, RSSI: %+5.2f dBm, RSRP: %+4.2f dBm, RSRQ: %4.2f dB\r",
+              ue_sync_get_cfo(&ue_sync)/1000, ue_sync_get_sfo(&ue_sync)/1000, 
+              10*log10(rssi*1000/4/cell.nof_prb/12/2)-prog_args.uhd_gain, 
+              10*log10(rsrp*1000)-prog_args.uhd_gain, 
+             10*log10(rsrq));                
+      }
+        
+    } else if (ret == 0) {
+      printf("Finding PSS... Peak: %8.1f, FrameCnt: %d, State: %d\r", 
+        sync_get_peak_value(&ue_sync.sfind), 
+        ue_sync.frame_total_cnt, ue_sync.state);      
+    }
+    sf_cnt++;                  
+  } // Main loop
+
+  ue_sync_free(&ue_sync);
+  cuhd_close(uhd);
+  printf("\nBye\n");
+  exit(0);
+}
+
+
+