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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 <strings.h>
#include <unistd.h>
#include "srslte/srslte.h"
char *input_file_name = NULL;
char *matlab_file_name = NULL;
srslte_cell_t cell = {
6, // nof_prb
1, // nof_ports
0, // bw_idx
0, // cell_id
SRSLTE_CP_NORM, // cyclic prefix
SRSLTE_PHICH_R_1, // PHICH resources
SRSLTE_PHICH_NORM // PHICH length
};
int flen;
FILE *fmatlab = NULL;
srslte_filesource_t fsrc;
cf_t *input_buffer, *fft_buffer, *ce[SRSLTE_MAX_PORTS];
srslte_pcfich_t pcfich;
srslte_regs_t regs;
srslte_ofdm_t fft;
srslte_chest_dl_t chest;
void usage(char *prog) {
printf("Usage: %s [vcoe] -i input_file\n", prog);
printf("\t-o output matlab file name [Default Disabled]\n");
printf("\t-c cell.id [Default %d]\n", cell.id);
printf("\t-p cell.nof_ports [Default %d]\n", cell.nof_ports);
printf("\t-n cell.nof_prb [Default %d]\n", cell.nof_prb);
printf("\t-e Set extended prefix [Default Normal]\n");
printf("\t-v [set srslte_verbose to debug, default none]\n");
}
void parse_args(int argc, char **argv) {
int opt;
while ((opt = getopt(argc, argv, "iovcenp")) != -1) {
switch(opt) {
case 'i':
input_file_name = argv[optind];
break;
case 'c':
cell.id = atoi(argv[optind]);
break;
case 'n':
cell.nof_prb = atoi(argv[optind]);
break;
case 'p':
cell.nof_ports = atoi(argv[optind]);
break;
case 'o':
matlab_file_name = argv[optind];
break;
case 'v':
srslte_verbose++;
break;
case 'e':
cell.cp = SRSLTE_CP_EXT;
break;
default:
usage(argv[0]);
exit(-1);
}
}
if (!input_file_name) {
usage(argv[0]);
exit(-1);
}
}
int base_init() {
int i;
if (srslte_filesource_init(&fsrc, input_file_name, SRSLTE_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 = SRSLTE_SF_LEN(srslte_symbol_sz(cell.nof_prb));
input_buffer = malloc(flen * sizeof(cf_t));
if (!input_buffer) {
perror("malloc");
exit(-1);
}
fft_buffer = malloc(SRSLTE_SF_LEN_RE(cell.nof_prb, cell.cp) * sizeof(cf_t));
if (!fft_buffer) {
perror("malloc");
return -1;
}
for (i=0;i<SRSLTE_MAX_PORTS;i++) {
ce[i] = malloc(SRSLTE_SF_LEN_RE(cell.nof_prb, cell.cp) * sizeof(cf_t));
if (!ce[i]) {
perror("malloc");
return -1;
}
}
if (srslte_chest_dl_init(&chest, cell)) {
fprintf(stderr, "Error initializing equalizer\n");
return -1;
}
if (srslte_ofdm_rx_init(&fft, cell.cp, cell.nof_prb)) {
fprintf(stderr, "Error initializing FFT\n");
return -1;
}
if (srslte_regs_init(&regs, cell)) {
fprintf(stderr, "Error initiating REGs\n");
return -1;
}
if (srslte_pcfich_init(&pcfich, &regs, cell)) {
fprintf(stderr, "Error creating PBCH object\n");
return -1;
}
DEBUG("Memory init OK\n",0);
return 0;
}
void base_free() {
int i;
srslte_filesource_free(&fsrc);
if (fmatlab) {
fclose(fmatlab);
}
free(input_buffer);
free(fft_buffer);
srslte_filesource_free(&fsrc);
for (i=0;i<SRSLTE_MAX_PORTS;i++) {
free(ce[i]);
}
srslte_chest_dl_free(&chest);
srslte_ofdm_rx_free(&fft);
srslte_pcfich_free(&pcfich);
srslte_regs_free(&regs);
}
int main(int argc, char **argv) {
uint32_t cfi;
float cfi_corr;
int n;
if (argc < 3) {
usage(argv[0]);
exit(-1);
}
parse_args(argc,argv);
if (base_init()) {
fprintf(stderr, "Error initializing receiver\n");
exit(-1);
}
n = srslte_filesource_read(&fsrc, input_buffer, flen);
srslte_ofdm_rx_sf(&fft, input_buffer, fft_buffer);
if (fmatlab) {
fprintf(fmatlab, "infft=");
srslte_vec_fprint_c(fmatlab, input_buffer, flen);
fprintf(fmatlab, ";\n");
fprintf(fmatlab, "outfft=");
srslte_vec_sc_prod_cfc(fft_buffer, 1000.0, fft_buffer, SRSLTE_CP_NSYMB(cell.cp) * cell.nof_prb * SRSLTE_NRE);
srslte_vec_fprint_c(fmatlab, fft_buffer, SRSLTE_CP_NSYMB(cell.cp) * cell.nof_prb * SRSLTE_NRE);
fprintf(fmatlab, ";\n");
srslte_vec_sc_prod_cfc(fft_buffer, 0.001, fft_buffer, SRSLTE_CP_NSYMB(cell.cp) * cell.nof_prb * SRSLTE_NRE);
}
/* Get channel estimates for each port */
srslte_chest_dl_estimate(&chest, fft_buffer, ce, 0);
INFO("Decoding PCFICH\n", 0);
n = srslte_pcfich_decode(&pcfich, fft_buffer, ce, srslte_chest_dl_get_noise_estimate(&chest), 0, &cfi, &cfi_corr);
printf("cfi: %d, distance: %f\n", cfi, cfi_corr);
base_free();
if (n < 0) {
fprintf(stderr, "Error decoding PCFICH\n");
exit(-1);
} else if (n == 0) {
printf("Could not decode PCFICH\n");
exit(-1);
} else {
if (cfi_corr > 2.8 && cfi == 1) {
exit(0);
} else {
exit(-1);
}
}
}