srsRAN_4G/examples/rssi_scan_usrp.c

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <strings.h>
#include <unistd.h>
#include <math.h>

#include "lte.h"
#include "uhd.h"

int nof_slots=1000;
int band;

cf_t *input_buffer, *fft_buffer;
void *uhd;
int earfcn_start = -1, earfcn_end = -1;

#define MAX_EARFCN 1000
lte_earfcn_t channels[MAX_EARFCN];

#define MHZ 1000000
#define SAMP_FREQ 1920000

void usage(char *prog) {
	printf("Usage: %s [nvse] -b band\n", prog);
	printf("\t-s earfcn_start [Default All]\n");
	printf("\t-e earfcn_end [Default All]\n");
	printf("\t-n number of frames [Default %d]\n", nof_slots);
	printf("\t-v [set verbose to debug, default none]\n");
}

void parse_args(int argc, char **argv) {
	int opt;
	while ((opt = getopt(argc, argv, "sebnv")) != -1) {
		switch(opt) {
		case 'b':
			band = atoi(argv[optind]);
			break;
		case 's':
			earfcn_start = atoi(argv[optind]);
			break;
		case 'e':
			earfcn_end = atoi(argv[optind]);
			break;
		case 'n':
			nof_slots = atoi(argv[optind]);
			break;
		case 'v':
			verbose++;
			break;
		default:
			usage(argv[0]);
			exit(-1);
		}
	}
}

int base_init() {

	input_buffer = malloc(4 * 960 * sizeof(cf_t));
	if (!input_buffer) {
		perror("malloc");
		exit(-1);
	}

	/* open UHD device */
	printf("Opening UHD device...\n");
	if (uhd_open("",&uhd)) {
		fprintf(stderr, "Error opening uhd\n");
		exit(-1);
	}

	printf("Setting sampling frequency %.2f MHz\n", (float) SAMP_FREQ/MHZ);
	uhd_set_rx_srate(uhd, SAMP_FREQ);

	printf("Starting receiver...\n");
	uhd_start_rx_stream(uhd);
	return 0;
}



int main(int argc, char **argv) {
	int frame_cnt;
	int i;
	int nsamples;
	float rssi[MAX_EARFCN];

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

	parse_args(argc,argv);

	if (base_init()) {
		fprintf(stderr, "Error initializing memory\n");
		exit(-1);
	}

	int nof_bands = lte_band_get_fd_band(band, channels, earfcn_start, earfcn_end, MAX_EARFCN);
	printf("Scanning %d freqs in band %d\n", nof_bands, band);
	for (i=0;i<nof_bands;i++) {
		uhd_set_rx_freq(uhd, (double) channels[i].fd * MHZ);
		frame_cnt = 0;
		nsamples=0;
		rssi[i]=0;
		while(frame_cnt < nof_slots) {
			nsamples += uhd_recv(uhd, input_buffer, 1920, 1);
			rssi[i] += vec_avg_power_cf(input_buffer, 1920);
			frame_cnt++;
		}
		printf("[%3d/%d]: Scanning earfcn %d freq %.2f MHz RSSI %.2f dBm\n", i, nof_bands,
				channels[i].id, channels[i].fd, 10*log10f(rssi[i]) + 30);
	}

	FILE *f = fopen("output.m", "w");
	if (!f) {
		perror("fopen");
		exit(-1);
	}
	fprintf(f, "fd=[");
	for (i=0;i<nof_bands;i++) {
		fprintf(f, "%g, ", channels[i].fd);
	}
	fprintf(f, "];\n");

	fprintf(f, "rssi=[");
	for (i=0;i<nof_bands;i++) {
		fprintf(f, "%g, ", rssi[i]);
	}
	fprintf(f, "];\n");
	fprintf(f, "plot(fd/1000, 10*log10(rssi)+30)\ngrid on\nxlabel('f_d [Ghz]')\nylabel('RSSI [dBm]')\n");
	fclose(f);

	free(input_buffer);

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