/** 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 PDSCH from the received symbols
*/
int srslte_pdsch_decode(srslte_pdsch_t *q,
srslte_pdsch_cfg_t *cfg, srslte_softbuffer_rx_t *softbuffers[SRSLTE_MAX_CODEWORDS],
cf_t *sf_symbols[SRSLTE_MAX_PORTS], cf_t *ce[SRSLTE_MAX_PORTS][SRSLTE_MAX_PORTS],
float noise_estimate, uint16_t rnti, uint8_t *data[SRSLTE_MAX_CODEWORDS],
bool acks[SRSLTE_MAX_CODEWORDS])
{
/* Set pointers for layermapping & precoding */
uint32_t i;
cf_t *x[SRSLTE_MAX_LAYERS];
if (q != NULL &&
sf_symbols != NULL &&
data != NULL &&
cfg != NULL)
{
uint32_t nof_tb = SRSLTE_RA_DL_GRANT_NOF_TB(&cfg->grant);
INFO("Decoding PDSCH SF: %d, RNTI: 0x%x, NofSymbols: %d, C_prb=%d, mimo_type=%s, nof_layers=%d, nof_tb=%d\n",
cfg->sf_idx, rnti, cfg->nbits[0].nof_re, cfg->grant.nof_prb, srslte_mod_string(cfg->grant.mcs->mod), cfg->nof_layers, nof_tb);
// Extract Symbols and Channel Estimates
for (int j=0;j<q->nof_rx_antennas;j++) {
int n = srslte_pdsch_get(q, sf_symbols[j], q->symbols[j], &cfg->grant, cfg->nbits[0].lstart, cfg->sf_idx);
if (n != cfg->nbits[0].nof_re) {
fprintf(stderr, "Error expecting %d symbols but got %d\n", cfg->nbits[0].nof_re, n);
return SRSLTE_ERROR;
}
for (i = 0; i < q->cell.nof_ports; i++) {
n = srslte_pdsch_get(q, ce[i][j], q->ce[i][j], &cfg->grant, cfg->nbits[0].lstart, cfg->sf_idx);
if (n != cfg->nbits[0].nof_re) {
fprintf(stderr, "Error expecting %d symbols but got %d\n", cfg->nbits[0].nof_re, n);
return SRSLTE_ERROR;
}
}
}
// Prepare layers
int nof_symbols [SRSLTE_MAX_CODEWORDS];
nof_symbols[0] = cfg->nbits[0].nof_re * nof_tb / cfg->nof_layers;
nof_symbols[1] = cfg->nbits[1].nof_re * nof_tb / cfg->nof_layers;
if (cfg->nof_layers == nof_tb) {
/* Skip layer demap */
for (i = 0; i < cfg->nof_layers; i++) {
x[i] = q->d[i];
}
} else {
/* number of layers equals number of ports */
for (i = 0; i < cfg->nof_layers; i++) {
x[i] = q->x[i];
}
memset(&x[cfg->nof_layers], 0, sizeof(cf_t*) * (SRSLTE_MAX_LAYERS - cfg->nof_layers));
}
float pdsch_scaling = 1.0f;
if (q->rho_a != 0.0f) {
pdsch_scaling = q->rho_a;
}
// Pre-decoder
if (srslte_predecoding_type(q->symbols, q->ce, x, q->nof_rx_antennas, q->cell.nof_ports, cfg->nof_layers,
cfg->codebook_idx, cfg->nbits[0].nof_re, cfg->mimo_type, pdsch_scaling, noise_estimate)<0) {
DEBUG("Error predecoding\n");
return SRSLTE_ERROR;
}
// Layer demapping only if necessary
if (cfg->nof_layers != nof_tb) {
srslte_layerdemap_type(x, q->d, cfg->nof_layers, nof_tb,
nof_symbols[0], nof_symbols, cfg->mimo_type);
}
/* Codeword decoding: Implementation of 3GPP 36.212 Table 5.3.3.1.5-1 and Table 5.3.3.1.5-2 */
uint32_t cw_idx = (nof_tb == SRSLTE_MAX_TB && cfg->tb_cw_swap) ? 1 : 0;
for (uint32_t tb_idx = 0; tb_idx < SRSLTE_MAX_TB; tb_idx++) {
/* Decode only if transport block is enabled and the default ACK is not true */
if (cfg->grant.tb_en[tb_idx]) {
if (!acks[tb_idx]) {
int ret = srslte_pdsch_codeword_decode(q, cfg, softbuffers[tb_idx], rnti, data[tb_idx], cw_idx, tb_idx, &acks[tb_idx]);
/* Check if there has been any execution error */
if (ret) {
return ret;
}
}
cw_idx = (cw_idx + 1) % SRSLTE_MAX_CODEWORDS;
}
}
pdsch_decode_debug(q, cfg, sf_symbols, ce);
return SRSLTE_SUCCESS;
} else {
return SRSLTE_ERROR_INVALID_INPUTS;
}
}
