262 lines
7.6 KiB
C
262 lines
7.6 KiB
C
/**
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*
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* \section COPYRIGHT
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*
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* Copyright 2013-2015 Software Radio Systems Limited
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*
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* \section LICENSE
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*
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* This file is part of the srsLTE library.
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*
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* srsLTE is free software: you can redistribute it and/or modify
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* it under the terms of the GNU Affero General Public License as
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* published by the Free Software Foundation, either version 3 of
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* the License, or (at your option) any later version.
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*
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* srsLTE is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Affero General Public License for more details.
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*
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* A copy of the GNU Affero General Public License can be found in
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* the LICENSE file in the top-level directory of this distribution
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* and at http://www.gnu.org/licenses/.
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*
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <strings.h>
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#include <unistd.h>
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#include <math.h>
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#include <sys/time.h>
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#include <unistd.h>
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#include "srslte/srslte.h"
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#include "srslte/phy/rf/rf.h"
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#include "srslte/phy/rf/rf_utils.h"
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int rf_rssi_scan(srslte_rf_t *rf, float *freqs, float *rssi, int nof_bands, double fs, int nsamp) {
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int i, j;
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int ret = -1;
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cf_t *buffer;
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double f;
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buffer = calloc(nsamp, sizeof(cf_t));
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if (!buffer) {
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goto free_and_exit;
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}
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srslte_rf_set_rx_gain(rf, 20.0);
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srslte_rf_set_rx_srate(rf, fs);
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for (i=0;i<nof_bands;i++) {
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srslte_rf_stop_rx_stream(rf);
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f = (double) freqs[i];
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srslte_rf_set_rx_freq(rf, f);
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srslte_rf_rx_wait_lo_locked(rf);
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usleep(10000);
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srslte_rf_start_rx_stream(rf);
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/* discard first samples */
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for (j=0;j<2;j++) {
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if (srslte_rf_recv(rf, buffer, nsamp, 1) != nsamp) {
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goto free_and_exit;
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}
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}
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rssi[i] = srslte_vec_avg_power_cf(buffer, nsamp);
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printf("[%3d]: Freq %4.1f Mhz - RSSI: %3.2f dBm\r", i, f/1000000, 10*log10f(rssi[i]) + 30); fflush(stdout);
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if (SRSLTE_VERBOSE_ISINFO()) {
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printf("\n");
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}
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}
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srslte_rf_stop_rx_stream(rf);
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ret = 0;
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free_and_exit:
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free(buffer);
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return ret;
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}
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int srslte_rf_recv_wrapper_cs(void *h, cf_t *data[SRSLTE_MAX_PORTS], uint32_t nsamples, srslte_timestamp_t *t) {
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DEBUG(" ---- Receive %d samples ---- \n", nsamples);
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void *ptr[SRSLTE_MAX_PORTS];
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for (int i=0;i<SRSLTE_MAX_PORTS;i++) {
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ptr[i] = data[i];
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}
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return srslte_rf_recv_with_time_multi(h, ptr, nsamples, 1, NULL, NULL);
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}
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double srslte_rf_set_rx_gain_th_wrapper(void *h, double f) {
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return srslte_rf_set_rx_gain_th((srslte_rf_t*) h, f);
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}
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/** This function is simply a wrapper to the ue_cell_search module for rf devices
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* Return 1 if the MIB is decoded, 0 if not or -1 on error.
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*/
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int rf_mib_decoder(srslte_rf_t *rf, uint32_t nof_rx_antennas,cell_search_cfg_t *config, srslte_cell_t *cell, float *cfo) {
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int ret = SRSLTE_ERROR;
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srslte_ue_mib_sync_t ue_mib;
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uint8_t bch_payload[SRSLTE_BCH_PAYLOAD_LEN];
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if (srslte_ue_mib_sync_init_multi(&ue_mib, srslte_rf_recv_wrapper_cs, nof_rx_antennas, (void*) rf)) {
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fprintf(stderr, "Error initiating srslte_ue_mib_sync\n");
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goto clean_exit;
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}
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if (srslte_ue_mib_sync_set_cell(&ue_mib, cell->id, cell->cp)) {
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fprintf(stderr, "Error initiating srslte_ue_mib_sync\n");
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goto clean_exit;
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}
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if (config->init_agc > 0) {
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srslte_ue_sync_start_agc(&ue_mib.ue_sync, srslte_rf_set_rx_gain_th_wrapper, config->init_agc);
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}
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int srate = srslte_sampling_freq_hz(SRSLTE_UE_MIB_NOF_PRB);
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INFO("Setting sampling frequency %.2f MHz for PSS search\n", (float) srate/1000000);
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srslte_rf_set_rx_srate(rf, (float) srate);
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INFO("Starting receiver...\n", 0);
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srslte_rf_start_rx_stream(rf);
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// Set CFO if available
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if (cfo) {
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srslte_ue_sync_set_cfo(&ue_mib.ue_sync, *cfo);
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}
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/* Find and decody MIB */
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ret = srslte_ue_mib_sync_decode(&ue_mib, config->max_frames_pbch, bch_payload, &cell->nof_ports, NULL);
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if (ret < 0) {
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fprintf(stderr, "Error decoding MIB\n");
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goto clean_exit;
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}
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if (ret == 1) {
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srslte_pbch_mib_unpack(bch_payload, cell, NULL);
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}
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// Save AGC value
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if (config->init_agc > 0) {
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config->init_agc = srslte_agc_get_gain(&ue_mib.ue_sync.agc);
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}
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// Save CFO
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if (cfo) {
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*cfo = srslte_ue_sync_get_cfo(&ue_mib.ue_sync);
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}
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clean_exit:
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srslte_rf_stop_rx_stream(rf);
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srslte_ue_mib_sync_free(&ue_mib);
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return ret;
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}
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/** This function is simply a wrapper to the ue_cell_search module for rf devices
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*/
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int rf_cell_search(srslte_rf_t *rf, uint32_t nof_rx_antennas,
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cell_search_cfg_t *config,
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int force_N_id_2, srslte_cell_t *cell, float *cfo)
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{
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int ret = SRSLTE_ERROR;
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srslte_ue_cellsearch_t cs;
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srslte_ue_cellsearch_result_t found_cells[3];
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bzero(found_cells, 3*sizeof(srslte_ue_cellsearch_result_t));
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if (srslte_ue_cellsearch_init_multi(&cs, config->max_frames_pss, srslte_rf_recv_wrapper_cs, nof_rx_antennas, (void*) rf)) {
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fprintf(stderr, "Error initiating UE cell detect\n");
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return SRSLTE_ERROR;
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}
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if (config->nof_valid_pss_frames) {
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srslte_ue_cellsearch_set_nof_valid_frames(&cs, config->nof_valid_pss_frames);
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}
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if (config->init_agc > 0) {
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srslte_ue_sync_start_agc(&cs.ue_sync, srslte_rf_set_rx_gain_th_wrapper, config->init_agc);
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}
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INFO("Setting sampling frequency %.2f MHz for PSS search\n", SRSLTE_CS_SAMP_FREQ/1000000);
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srslte_rf_set_rx_srate(rf, SRSLTE_CS_SAMP_FREQ);
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INFO("Starting receiver...\n", 0);
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srslte_rf_start_rx_stream(rf);
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/* Find a cell in the given N_id_2 or go through the 3 of them to find the strongest */
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uint32_t max_peak_cell = 0;
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if (force_N_id_2 >= 0) {
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ret = srslte_ue_cellsearch_scan_N_id_2(&cs, force_N_id_2, &found_cells[force_N_id_2]);
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max_peak_cell = force_N_id_2;
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} else {
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ret = srslte_ue_cellsearch_scan(&cs, found_cells, &max_peak_cell);
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}
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if (ret < 0) {
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fprintf(stderr, "Error searching cell\n");
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return SRSLTE_ERROR;
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} else if (ret == 0) {
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fprintf(stderr, "Could not find any cell in this frequency\n");
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return SRSLTE_SUCCESS;
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}
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for (int i=0;i<3;i++) {
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if (i == max_peak_cell) {
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printf("*");
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} else {
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printf(" ");
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}
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printf("Found Cell_id: %3d CP: %s, DetectRatio=%2.0f%% PSR=%.2f, Power=%.1f dBm\n",
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found_cells[i].cell_id, srslte_cp_string(found_cells[i].cp),
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found_cells[i].mode*100,
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found_cells[i].psr, 20*log10(found_cells[i].peak*1000));
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}
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// Save result
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if (cell) {
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cell->id = found_cells[max_peak_cell].cell_id;
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cell->cp = found_cells[max_peak_cell].cp;
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}
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// Save CFO
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if (cfo) {
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*cfo = found_cells[max_peak_cell].cfo;
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}
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// Save AGC value for MIB decoding
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if (config->init_agc > 0) {
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config->init_agc = srslte_agc_get_gain(&cs.ue_sync.agc);
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}
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srslte_rf_stop_rx_stream(rf);
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srslte_ue_cellsearch_free(&cs);
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return ret;
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}
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/* Finds a cell and decodes MIB from the PBCH.
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* Returns 1 if the cell is found and MIB is decoded successfully.
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* 0 if no cell was found or MIB could not be decoded,
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* -1 on error
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*/
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int rf_search_and_decode_mib(srslte_rf_t *rf, uint32_t nof_rx_antennas, cell_search_cfg_t *config, int force_N_id_2, srslte_cell_t *cell, float *cfo)
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{
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int ret = SRSLTE_ERROR;
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printf("Searching for cell...\n");
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ret = rf_cell_search(rf, nof_rx_antennas, config, force_N_id_2, cell, cfo);
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if (ret > 0) {
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printf("Decoding PBCH for cell %d (N_id_2=%d)\n", cell->id, cell->id%3);
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ret = rf_mib_decoder(rf, nof_rx_antennas, config, cell, cfo);
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if (ret < 0) {
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fprintf(stderr, "Could not decode PBCH from CELL ID %d\n", cell->id);
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return SRSLTE_ERROR;
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}
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}
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return ret;
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}
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