int srslte_ue_dl_decode_estimate(srslte_ue_dl_t *q, uint32_t sf_idx, uint32_t *cfi) {
float cfi_corr;
if (q && cfi && sf_idx < SRSLTE_NSUBFRAMES_X_FRAME) {
/* Get channel estimates for each port */
srslte_chest_dl_estimate(&q->chest, q->sf_symbols, q->ce, sf_idx);
/* First decode PCFICH and obtain CFI */
if (srslte_pcfich_decode(&q->pcfich, q->sf_symbols, q->ce,
srslte_chest_dl_get_noise_estimate(&q->chest), sf_idx, cfi, &cfi_corr)<0) {
fprintf(stderr, "Error decoding PCFICH\n");
return SRSLTE_ERROR;
}
INFO("Decoded CFI=%d with correlation %.2f, sf_idx=%d\n", *cfi, cfi_corr, sf_idx);
if (srslte_regs_set_cfi(&q->regs, *cfi)) {
fprintf(stderr, "Error setting CFI\n");
return SRSLTE_ERROR;
}
return SRSLTE_SUCCESS;
} else {
return SRSLTE_ERROR_INVALID_INPUTS;
}
}
static int estimate_pdcch_pcfich(srslte_ue_dl_t* q, srslte_dl_sf_cfg_t* sf, srslte_ue_dl_cfg_t* cfg)
{
if (q) {
float cfi_corr = 0;
set_mi_value(q, sf, cfg);
/* Get channel estimates for each port */
srslte_chest_dl_estimate_cfg(&q->chest, sf, &cfg->chest_cfg, q->sf_symbols, &q->chest_res);
/* First decode PCFICH and obtain CFI */
if (srslte_pcfich_decode(&q->pcfich, sf, &q->chest_res, q->sf_symbols, &cfi_corr) < 0) {
ERROR("Error decoding PCFICH\n");
return SRSLTE_ERROR;
}
if (q->cell.frame_type == SRSLTE_TDD && ((sf->tti % 10) == 1 || (sf->tti % 10) == 6) && sf->cfi == 3) {
sf->cfi = 2;
INFO("Received CFI=3 in subframe 1 or 6 and TDD. Setting to 2\n");
}
if (srslte_pdcch_extract_llr(&q->pdcch, sf, &q->chest_res, q->sf_symbols)) {
ERROR("Extracting PDCCH LLR\n");
return false;
}
INFO("Decoded CFI=%d with correlation %.2f, sf_idx=%d\n", sf->cfi, cfi_corr, sf->tti % 10);
return SRSLTE_SUCCESS;
} else {
return SRSLTE_ERROR_INVALID_INPUTS;
}
}
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);
}
}
}
int main(int argc, char **argv) {
srslte_pcfich_t pcfich;
srslte_regs_t regs;
int i, j;
cf_t *ce[SRSLTE_MAX_PORTS];
int nof_re;
cf_t *slot_symbols[SRSLTE_MAX_PORTS];
uint32_t cfi, cfi_rx, nsf;
int cid, max_cid;
float corr_res;
parse_args(argc,argv);
nof_re = SRSLTE_CP_NORM_NSYMB * cell.nof_prb * SRSLTE_NRE;
/* init memory */
for (i=0;i<SRSLTE_MAX_PORTS;i++) {
ce[i] = malloc(sizeof(cf_t) * nof_re);
if (!ce[i]) {
perror("malloc");
exit(-1);
}
for (j=0;j<nof_re;j++) {
ce[i][j] = 1;
}
slot_symbols[i] = malloc(sizeof(cf_t) * nof_re);
if (!slot_symbols[i]) {
perror("malloc");
exit(-1);
}
}
if (cell.id == 1000) {
cid = 0;
max_cid = 503;
} else {
cid = cell.id;
max_cid = cell.id;
}
while(cid <= max_cid) {
cell.id = cid;
printf("Testing CellID=%d...\n", cid);
if (srslte_regs_init(®s, cell)) {
fprintf(stderr, "Error initiating regs\n");
exit(-1);
}
if (srslte_pcfich_init(&pcfich, ®s, cell)) {
fprintf(stderr, "Error creating PBCH object\n");
exit(-1);
}
for (nsf=0;nsf<10;nsf++) {
for (cfi=1;cfi<4;cfi++) {
srslte_pcfich_encode(&pcfich, cfi, slot_symbols, nsf);
/* combine outputs */
for (i=1;i<cell.nof_ports;i++) {
for (j=0;j<nof_re;j++) {
slot_symbols[0][j] += slot_symbols[i][j];
}
}
if (srslte_pcfich_decode(&pcfich, slot_symbols[0], ce, 0, nsf, &cfi_rx, &corr_res)<0) {
exit(-1);
}
INFO("cfi_tx: %d, cfi_rx: %d, ns: %d, distance: %f\n",
cfi, cfi_rx, nsf, corr_res);
}
}
srslte_pcfich_free(&pcfich);
srslte_regs_free(®s);
cid++;
}
for (i=0;i<SRSLTE_MAX_PORTS;i++) {
free(ce[i]);
free(slot_symbols[i]);
}
printf("OK\n");
exit(0);
}
/* the gateway function */
void mexFunction(int nlhs, mxArray *plhs[], int nrhs, const mxArray *prhs[])
{
int i;
srslte_cell_t cell;
srslte_pcfich_t pcfich;
srslte_chest_dl_t chest;
srslte_ofdm_t fft;
srslte_regs_t regs;
uint32_t sf_idx;
cf_t *input_fft, *input_signal;
if (nrhs != NOF_INPUTS) {
help();
return;
}
if (mexutils_read_cell(ENBCFG, &cell)) {
help();
return;
}
if (mexutils_read_uint32_struct(ENBCFG, "NSubframe", &sf_idx)) {
help();
return;
}
if (srslte_chest_dl_init(&chest, cell)) {
mexErrMsgTxt("Error initializing equalizer\n");
return;
}
if (srslte_ofdm_rx_init(&fft, cell.cp, cell.nof_prb)) {
mexErrMsgTxt("Error initializing FFT\n");
return;
}
if (srslte_regs_init(®s, cell)) {
mexErrMsgTxt("Error initiating regs\n");
return;
}
if (srslte_pcfich_init(&pcfich, ®s, cell)) {
mexErrMsgTxt("Error creating PBCH object\n");
return;
}
/** Allocate input buffers */
if (mexutils_read_cf(INPUT, &input_signal) < 0) {
mexErrMsgTxt("Error reading input signal\n");
return;
}
input_fft = srslte_vec_malloc(SRSLTE_SF_LEN_RE(cell.nof_prb, cell.cp) * sizeof(cf_t));
// Set Channel estimates to 1.0 (ignore fading)
cf_t *ce[SRSLTE_MAX_PORTS];
for (i=0;i<cell.nof_ports;i++) {
ce[i] = srslte_vec_malloc(SRSLTE_SF_LEN_RE(cell.nof_prb, cell.cp) * sizeof(cf_t));
}
srslte_ofdm_rx_sf(&fft, input_signal, input_fft);
if (nrhs > NOF_INPUTS) {
cf_t *cearray;
mexutils_read_cf(prhs[NOF_INPUTS], &cearray);
for (i=0;i<cell.nof_ports;i++) {
for (int j=0;j<SRSLTE_SF_LEN_RE(cell.nof_prb, cell.cp);j++) {
ce[i][j] = *cearray;
cearray++;
}
}
} else {
srslte_chest_dl_estimate(&chest, input_fft, ce, sf_idx);
}
float noise_power;
if (nrhs > NOF_INPUTS + 1) {
noise_power = mxGetScalar(prhs[NOF_INPUTS+1]);
} else {
noise_power = srslte_chest_dl_get_noise_estimate(&chest);
}
uint32_t cfi;
float corr_res;
int n = srslte_pcfich_decode(&pcfich, input_fft, ce, noise_power, sf_idx, &cfi, &corr_res);
if (nlhs >= 1) {
if (n < 0) {
plhs[0] = mxCreateDoubleScalar(-1);
} else {
plhs[0] = mxCreateDoubleScalar(cfi);
}
}
if (nlhs >= 2) {
mexutils_write_cf(pcfich.d, &plhs[1], 16, 1);
}
if (nlhs >= 3) {
mexutils_write_cf(pcfich.symbols[0], &plhs[2], 16, 1);
}
srslte_chest_dl_free(&chest);
srslte_ofdm_rx_free(&fft);
srslte_pcfich_free(&pcfich);
srslte_regs_free(®s);
for (i=0;i<cell.nof_ports;i++) {
free(ce[i]);
}
free(input_signal);
free(input_fft);
return;
}