/* Decodes the PCFICH channel and saves the CFI in the cfi pointer.
*
* Returns 1 if successfully decoded the CFI, 0 if not and -1 on error
*/
int srslte_pcfich_decode(srslte_pcfich_t *q, cf_t *slot_symbols, cf_t *ce[SRSLTE_MAX_PORTS], float noise_estimate,
uint32_t nsubframe, uint32_t *cfi, float *corr_result)
{
/* Set pointers for layermapping & precoding */
int i;
cf_t *x[SRSLTE_MAX_LAYERS];
cf_t *ce_precoding[SRSLTE_MAX_PORTS];
if (q != NULL &&
slot_symbols != NULL &&
nsubframe < SRSLTE_NSUBFRAMES_X_FRAME)
{
/* number of layers equals number of ports */
for (i = 0; i < SRSLTE_MAX_PORTS; i++) {
x[i] = q->x[i];
}
for (i = 0; i < SRSLTE_MAX_PORTS; i++) {
ce_precoding[i] = q->ce[i];
}
/* extract symbols */
if (q->nof_symbols
!= srslte_regs_pcfich_get(q->regs, slot_symbols, q->symbols[0])) {
fprintf(stderr, "There was an error getting the PCFICH symbols\n");
return SRSLTE_ERROR;
}
/* extract channel estimates */
for (i = 0; i < q->cell.nof_ports; i++) {
if (q->nof_symbols != srslte_regs_pcfich_get(q->regs, ce[i], q->ce[i])) {
fprintf(stderr, "There was an error getting the PCFICH symbols\n");
return SRSLTE_ERROR;
}
}
/* in control channels, only diversity is supported */
if (q->cell.nof_ports == 1) {
/* no need for layer demapping */
srslte_predecoding_single(q->symbols[0], q->ce[0], q->d, q->nof_symbols, noise_estimate);
} else {
srslte_predecoding_diversity(q->symbols[0], ce_precoding, x,
q->cell.nof_ports, q->nof_symbols);
srslte_layerdemap_diversity(x, q->d, q->cell.nof_ports,
q->nof_symbols / q->cell.nof_ports);
}
/* demodulate symbols */
srslte_demod_soft_demodulate(SRSLTE_MOD_QPSK, q->d, q->data_f, q->nof_symbols);
/* Scramble with the sequence for slot nslot */
srslte_scrambling_f(&q->seq[nsubframe], q->data_f);
/* decode CFI */
float corr = srslte_pcfich_cfi_decode(q, cfi);
if (corr_result) {
*corr_result = corr;
}
return 1;
} else {
return SRSLTE_ERROR_INVALID_INPUTS;
}
}
/* the gateway function */
void mexFunction(int nlhs, mxArray *plhs[], int nrhs, const mxArray *prhs[])
{
int i;
srslte_cell_t cell;
srslte_chest_dl_t chest;
srslte_precoding_t cheq;
cf_t *input_signal = NULL, *output_signal[SRSLTE_MAX_LAYERS];
cf_t *output_signal2 = NULL;
cf_t *ce[SRSLTE_MAX_PORTS];
double *outr0=NULL, *outi0=NULL;
double *outr1=NULL, *outi1=NULL;
double *outr2=NULL, *outi2=NULL;
if (!mxIsDouble(CELLID) && mxGetN(CELLID) != 1 &&
!mxIsDouble(PORTS) && mxGetN(PORTS) != 1 &&
mxGetM(CELLID) != 1) {
help();
return;
}
cell.id = (uint32_t) *((double*) mxGetPr(CELLID));
cell.nof_prb = mxGetM(INPUT)/SRSLTE_NRE;
cell.nof_ports = (uint32_t) *((double*) mxGetPr(PORTS));
if ((mxGetN(INPUT)%14) == 0) {
cell.cp = SRSLTE_CP_NORM;
} else if ((mxGetN(INPUT)%12)!=0) {
cell.cp = SRSLTE_CP_EXT;
} else {
mexErrMsgTxt("Invalid number of symbols\n");
help();
return;
}
if (srslte_chest_dl_init(&chest, cell)) {
mexErrMsgTxt("Error initiating channel estimator\n");
return;
}
int nsubframes;
if (cell.cp == SRSLTE_CP_NORM) {
nsubframes = mxGetN(INPUT)/14;
} else {
nsubframes = mxGetN(INPUT)/12;
}
uint32_t sf_idx=0;
if (nsubframes == 1) {
if (nrhs != NOF_INPUTS+1) {
mexErrMsgTxt("Received 1 subframe. Need to provide subframe index.\n");
help();
return;
}
sf_idx = (uint32_t) *((double*) mxGetPr(SFIDX));
}
if (nrhs > 5) {
uint32_t filter_len = 0;
float *filter;
double *f;
filter_len = mxGetNumberOfElements(FREQ_FILTER);
filter = malloc(sizeof(float) * filter_len);
f = (double*) mxGetPr(FREQ_FILTER);
for (i=0;i<filter_len;i++) {
filter[i] = (float) f[i];
}
srslte_chest_dl_set_filter_freq(&chest, filter, filter_len);
filter_len = mxGetNumberOfElements(TIME_FILTER);
filter = malloc(sizeof(float) * filter_len);
f = (double*) mxGetPr(TIME_FILTER);
for (i=0;i<filter_len;i++) {
filter[i] = (float) f[i];
}
srslte_chest_dl_set_filter_time(&chest, filter, filter_len);
}
double *inr=(double *)mxGetPr(INPUT);
double *ini=(double *)mxGetPi(INPUT);
/** Allocate input buffers */
int nof_re = 2*SRSLTE_CP_NSYMB(cell.cp)*cell.nof_prb*SRSLTE_NRE;
for (i=0;i<SRSLTE_MAX_PORTS;i++) {
ce[i] = srslte_vec_malloc(nof_re * sizeof(cf_t));
}
input_signal = srslte_vec_malloc(nof_re * sizeof(cf_t));
for (i=0;i<SRSLTE_MAX_PORTS;i++) {
output_signal[i] = srslte_vec_malloc(nof_re * sizeof(cf_t));
}
output_signal2 = srslte_vec_malloc(nof_re * sizeof(cf_t));
srslte_precoding_init(&cheq, nof_re);
/* Create output values */
if (nlhs >= 1) {
plhs[0] = mxCreateDoubleMatrix(nof_re * nsubframes, cell.nof_ports, mxCOMPLEX);
outr0 = mxGetPr(plhs[0]);
outi0 = mxGetPi(plhs[0]);
}
if (nlhs >= 2) {
plhs[1] = mxCreateDoubleMatrix(SRSLTE_REFSIGNAL_MAX_NUM_SF(cell.nof_prb)*nsubframes, cell.nof_ports, mxCOMPLEX);
outr1 = mxGetPr(plhs[1]);
outi1 = mxGetPi(plhs[1]);
}
if (nlhs >= 3) {
plhs[2] = mxCreateDoubleMatrix(nof_re * nsubframes, 1, mxCOMPLEX);
outr2 = mxGetPr(plhs[2]);
outi2 = mxGetPi(plhs[2]);
}
for (int sf=0;sf<nsubframes;sf++) {
/* Convert input to C complex type */
for (i=0;i<nof_re;i++) {
__real__ input_signal[i] = (float) *inr;
if (ini) {
__imag__ input_signal[i] = (float) *ini;
}
inr++;
ini++;
}
if (nsubframes != 1) {
sf_idx = sf%10;
}
if (srslte_chest_dl_estimate(&chest, input_signal, ce, sf_idx)) {
mexErrMsgTxt("Error running channel estimator\n");
return;
}
if (cell.nof_ports == 1) {
srslte_predecoding_single(input_signal, ce[0], output_signal2, nof_re, srslte_chest_dl_get_noise_estimate(&chest));
} else {
srslte_predecoding_diversity(&cheq, input_signal, ce, output_signal, cell.nof_ports, nof_re, srslte_chest_dl_get_noise_estimate(&chest));
srslte_layerdemap_diversity(output_signal, output_signal2, cell.nof_ports, nof_re/cell.nof_ports);
}
if (nlhs >= 1) {
for (int j=0;j<cell.nof_ports;j++) {
for (i=0;i<nof_re;i++) {
*outr0 = (double) crealf(ce[j][i]);
if (outi0) {
*outi0 = (double) cimagf(ce[j][i]);
}
outr0++;
outi0++;
}
}
}
if (nlhs >= 2) {
for (int j=0;j<cell.nof_ports;j++) {
for (i=0;i<SRSLTE_REFSIGNAL_NUM_SF(cell.nof_prb,j);i++) {
*outr1 = (double) crealf(chest.pilot_estimates_average[j][i]);
if (outi1) {
*outi1 = (double) cimagf(chest.pilot_estimates_average[j][i]);
}
outr1++;
outi1++;
}
}
}
if (nlhs >= 3) {
for (i=0;i<nof_re;i++) {
*outr2 = (double) crealf(output_signal2[i]);
if (outi2) {
*outi2 = (double) cimagf(output_signal2[i]);
}
outr2++;
outi2++;
}
}
}
if (nlhs >= 4) {
plhs[3] = mxCreateDoubleScalar(srslte_chest_dl_get_noise_estimate(&chest));
}
if (nlhs >= 5) {
plhs[4] = mxCreateDoubleScalar(srslte_chest_dl_get_rsrp(&chest));
}
srslte_chest_dl_free(&chest);
srslte_precoding_free(&cheq);
return;
}
/** Decodes the PDSCH from the received symbols
*/
int srslte_pdsch_decode_rnti(srslte_pdsch_t *q,
srslte_pdsch_cfg_t *cfg, srslte_softbuffer_rx_t *softbuffer,
cf_t *sf_symbols, cf_t *ce[SRSLTE_MAX_PORTS], float noise_estimate,
uint16_t rnti, uint8_t *data)
{
/* Set pointers for layermapping & precoding */
uint32_t i, n;
cf_t *x[SRSLTE_MAX_LAYERS];
if (q != NULL &&
sf_symbols != NULL &&
data != NULL &&
cfg != NULL)
{
INFO("Decoding PDSCH SF: %d, RNTI: 0x%x, Mod %s, TBS: %d, NofSymbols: %d, NofBitsE: %d, rv_idx: %d, C_prb=%d\n",
cfg->sf_idx, rnti, srslte_mod_string(cfg->grant.mcs.mod), cfg->grant.mcs.tbs, cfg->nbits.nof_re,
cfg->nbits.nof_bits, cfg->rv, cfg->grant.nof_prb);
/* number of layers equals number of ports */
for (i = 0; i < q->cell.nof_ports; i++) {
x[i] = q->x[i];
}
memset(&x[q->cell.nof_ports], 0, sizeof(cf_t*) * (SRSLTE_MAX_LAYERS - q->cell.nof_ports));
/* extract symbols */
n = srslte_pdsch_get(q, sf_symbols, q->symbols[0], &cfg->grant, cfg->nbits.lstart, cfg->sf_idx);
if (n != cfg->nbits.nof_re) {
fprintf(stderr, "Error expecting %d symbols but got %d\n", cfg->nbits.nof_re, n);
return SRSLTE_ERROR;
}
/* extract channel estimates */
for (i = 0; i < q->cell.nof_ports; i++) {
n = srslte_pdsch_get(q, ce[i], q->ce[i], &cfg->grant, cfg->nbits.lstart, cfg->sf_idx);
if (n != cfg->nbits.nof_re) {
fprintf(stderr, "Error expecting %d symbols but got %d\n", cfg->nbits.nof_re, n);
return SRSLTE_ERROR;
}
}
/* TODO: only diversity is supported */
if (q->cell.nof_ports == 1) {
/* no need for layer demapping */
srslte_predecoding_single(q->symbols[0], q->ce[0], q->d, cfg->nbits.nof_re, noise_estimate);
} else {
srslte_predecoding_diversity(&q->precoding, q->symbols[0], q->ce, x, q->cell.nof_ports,
cfg->nbits.nof_re, noise_estimate);
srslte_layerdemap_diversity(x, q->d, q->cell.nof_ports,
cfg->nbits.nof_re / q->cell.nof_ports);
}
if (SRSLTE_VERBOSE_ISDEBUG()) {
DEBUG("SAVED FILE pdsch_symbols.dat: symbols after equalization\n",0);
srslte_vec_save_file("pdsch_symbols.dat", q->d, cfg->nbits.nof_re*sizeof(cf_t));
}
/* demodulate symbols
* The MAX-log-MAP algorithm used in turbo decoding is unsensitive to SNR estimation,
* thus we don't need tot set it in the LLRs normalization
*/
srslte_demod_soft_demodulate_s(cfg->grant.mcs.mod, q->d, q->e, cfg->nbits.nof_re);
/* descramble */
if (rnti != q->rnti) {
srslte_sequence_t seq;
if (srslte_sequence_pdsch(&seq, rnti, 0, 2 * cfg->sf_idx, q->cell.id, cfg->nbits.nof_bits)) {
return SRSLTE_ERROR;
}
srslte_scrambling_s_offset(&seq, q->e, 0, cfg->nbits.nof_bits);
srslte_sequence_free(&seq);
} else {
srslte_scrambling_s_offset(&q->seq[cfg->sf_idx], q->e, 0, cfg->nbits.nof_bits);
}
if (SRSLTE_VERBOSE_ISDEBUG()) {
DEBUG("SAVED FILE llr.dat: LLR estimates after demodulation and descrambling\n",0);
srslte_vec_save_file("llr.dat", q->e, cfg->nbits.nof_bits*sizeof(int16_t));
}
return srslte_dlsch_decode(&q->dl_sch, cfg, softbuffer, q->e, data);
} else {
return SRSLTE_ERROR_INVALID_INPUTS;
}
}
/* Decodes the phich channel and saves the CFI in the cfi pointer.
*
* Returns 1 if successfully decoded the CFI, 0 if not and -1 on error
*/
int srslte_phich_decode(srslte_phich_t *q, cf_t *slot_symbols, cf_t *ce[SRSLTE_MAX_PORTS], float noise_estimate,
uint32_t ngroup, uint32_t nseq, uint32_t subframe, uint8_t *ack, float *distance) {
/* Set pointers for layermapping & precoding */
int i, j;
cf_t *x[SRSLTE_MAX_LAYERS];
cf_t *ce_precoding[SRSLTE_MAX_PORTS];
if (q == NULL || slot_symbols == NULL) {
return SRSLTE_ERROR_INVALID_INPUTS;
}
if (subframe >= SRSLTE_NSUBFRAMES_X_FRAME) {
fprintf(stderr, "Invalid nslot %d\n", subframe);
return SRSLTE_ERROR_INVALID_INPUTS;
}
if (SRSLTE_CP_ISEXT(q->cell.cp)) {
if (nseq >= SRSLTE_PHICH_EXT_NSEQUENCES) {
fprintf(stderr, "Invalid nseq %d\n", nseq);
return SRSLTE_ERROR_INVALID_INPUTS;
}
} else {
if (nseq >= SRSLTE_PHICH_NORM_NSEQUENCES) {
fprintf(stderr, "Invalid nseq %d\n", nseq);
return SRSLTE_ERROR_INVALID_INPUTS;
}
}
if (ngroup >= srslte_regs_phich_ngroups(q->regs)) {
fprintf(stderr, "Invalid ngroup %d\n", ngroup);
return SRSLTE_ERROR_INVALID_INPUTS;
}
DEBUG("Decoding PHICH Ngroup: %d, Nseq: %d\n", ngroup, nseq);
/* number of layers equals number of ports */
for (i = 0; i < SRSLTE_MAX_PORTS; i++) {
x[i] = q->x[i];
}
for (i = 0; i < SRSLTE_MAX_PORTS; i++) {
ce_precoding[i] = q->ce[i];
}
/* extract symbols */
if (SRSLTE_PHICH_MAX_NSYMB
!= srslte_regs_phich_get(q->regs, slot_symbols, q->symbols[0], ngroup)) {
fprintf(stderr, "There was an error getting the phich symbols\n");
return SRSLTE_ERROR;
}
/* extract channel estimates */
for (i = 0; i < q->cell.nof_ports; i++) {
if (SRSLTE_PHICH_MAX_NSYMB != srslte_regs_phich_get(q->regs, ce[i], q->ce[i], ngroup)) {
fprintf(stderr, "There was an error getting the phich symbols\n");
return SRSLTE_ERROR;
}
}
/* in control channels, only diversity is supported */
if (q->cell.nof_ports == 1) {
/* no need for layer demapping */
srslte_predecoding_single(q->symbols[0], q->ce[0], q->d0, SRSLTE_PHICH_MAX_NSYMB, noise_estimate);
} else {
srslte_predecoding_diversity(&q->precoding, q->symbols[0], ce_precoding, x,
q->cell.nof_ports, SRSLTE_PHICH_MAX_NSYMB, noise_estimate);
srslte_layerdemap_diversity(x, q->d0, q->cell.nof_ports,
SRSLTE_PHICH_MAX_NSYMB / q->cell.nof_ports);
}
DEBUG("Recv!!: \n", 0);
DEBUG("d0: ", 0);
if (SRSLTE_VERBOSE_ISDEBUG())
srslte_vec_fprint_c(stdout, q->d0, SRSLTE_PHICH_MAX_NSYMB);
if (SRSLTE_CP_ISEXT(q->cell.cp)) {
if (ngroup % 2) {
for (i = 0; i < SRSLTE_PHICH_EXT_MSYMB / 2; i++) {
q->d[2 * i + 0] = q->d0[4 * i + 2];
q->d[2 * i + 1] = q->d0[4 * i + 3];
}
} else {
for (i = 0; i < SRSLTE_PHICH_EXT_MSYMB / 2; i++) {
q->d[2 * i + 0] = q->d0[4 * i];
q->d[2 * i + 1] = q->d0[4 * i + 1];
}
}
} else {
memcpy(q->d, q->d0, SRSLTE_PHICH_MAX_NSYMB * sizeof(cf_t));
}
DEBUG("d: ", 0);
if (SRSLTE_VERBOSE_ISDEBUG())
srslte_vec_fprint_c(stdout, q->d, SRSLTE_PHICH_EXT_MSYMB);
srslte_scrambling_c(&q->seq[subframe], q->d);
/* De-spreading */
if (SRSLTE_CP_ISEXT(q->cell.cp)) {
for (i = 0; i < SRSLTE_PHICH_NBITS; i++) {
q->z[i] = 0;
for (j = 0; j < SRSLTE_PHICH_EXT_NSF; j++) {
q->z[i] += conjf(w_ext[nseq][j])
* q->d[i * SRSLTE_PHICH_EXT_NSF + j] / SRSLTE_PHICH_EXT_NSF;
}
}
} else {
for (i = 0; i < SRSLTE_PHICH_NBITS; i++) {
q->z[i] = 0;
for (j = 0; j < SRSLTE_PHICH_NORM_NSF; j++) {
q->z[i] += conjf(w_normal[nseq][j])
* q->d[i * SRSLTE_PHICH_NORM_NSF + j] / SRSLTE_PHICH_NORM_NSF;
}
}
}
DEBUG("z: ", 0);
if (SRSLTE_VERBOSE_ISDEBUG())
srslte_vec_fprint_c(stdout, q->z, SRSLTE_PHICH_NBITS);
srslte_demod_soft_demodulate(SRSLTE_MOD_BPSK, q->z, q->data_rx, SRSLTE_PHICH_NBITS);
if (ack) {
*ack = srslte_phich_ack_decode(q->data_rx, distance);
}
return SRSLTE_SUCCESS;
}
