fix handling of time start position in SRS FAPI at gNB

openair1/PHY/NR_TRANSPORT/srs_rx.c

@@ -67,23 +67,19 @@ int nr_get_srs_signal(PHY_VARS_gNB *gNB,
                       slot_t slot,
                       nfapi_nr_srs_pdu_t *srs_pdu,
                       nr_srs_info_t *nr_srs_info,
-                      int32_t srs_received_signal[][gNB->frame_parms.ofdm_symbol_size*(1<<srs_pdu->num_symbols)]) {
-
-#ifdef SRS_DEBUG
-  LOG_I(NR_PHY,"Calling %s function\n", __FUNCTION__);
-#endif
-
+                      int32_t srs_received_signal[][gNB->frame_parms.ofdm_symbol_size * (1 << srs_pdu->num_symbols)])
+{
   c16_t **rxdataF = gNB->common_vars.rxdataF;
   const NR_DL_FRAME_PARMS *frame_parms = &gNB->frame_parms;
 
   const uint16_t n_symbols = (slot % RU_RX_SLOT_DEPTH) * frame_parms->symbols_per_slot; // number of symbols until this slot
-  const uint8_t l0 = frame_parms->symbols_per_slot - 1 - srs_pdu->time_start_position;  // starting symbol in this slot
-  const uint64_t symbol_offset = (n_symbols+l0)*frame_parms->ofdm_symbol_size;
+  const uint8_t l0 = srs_pdu->time_start_position;  // starting symbol in this slot
+  const uint64_t symbol_offset = (n_symbols + l0) * frame_parms->ofdm_symbol_size;
   const uint64_t subcarrier_offset = frame_parms->first_carrier_offset + srs_pdu->bwp_start*NR_NB_SC_PER_RB;
 
   const uint8_t N_ap = 1<<srs_pdu->num_ant_ports;
-  const uint8_t N_symb_SRS = 1<<srs_pdu->num_symbols;
-  const uint8_t K_TC = 2<<srs_pdu->comb_size;
+  const uint8_t N_symb_SRS = 1 << srs_pdu->num_symbols;
+  const uint8_t K_TC = 2 << srs_pdu->comb_size;
   const uint16_t M_sc_b_SRS = srs_bandwidth_config[srs_pdu->config_index][srs_pdu->bandwidth_index][0] * NR_NB_SC_PER_RB/K_TC;
 
   int32_t *rx_signal;

openair1/SCHED_NR/phy_procedures_nr_gNB.c

@@ -613,10 +613,9 @@ static void fill_ul_rb_mask(PHY_VARS_gNB *gNB, int frame_rx, int slot_rx, uint32
     if (srs) {
       if ((srs->active == 1) && (srs->frame == frame_rx) && (srs->slot == slot_rx)) {
         nfapi_nr_srs_pdu_t *srs_pdu = &srs->srs_pdu;
-        for(int symbol = 0; symbol<(1<<srs_pdu->num_symbols); symbol++) {
+        for(int symbol = 0; symbol < (1 << srs_pdu->num_symbols); symbol++) {
           for(rb = srs_pdu->bwp_start; rb < (srs_pdu->bwp_start+srs_pdu->bwp_size); rb++) {
-            rb_mask_ul[gNB->frame_parms.symbols_per_slot - srs_pdu->time_start_position - 1 + symbol][rb >> 5] |= 1U
-                                                                                                                       << (rb & 31);
+            rb_mask_ul[srs_pdu->time_start_position + symbol][rb >> 5] |= 1U << (rb & 31);
           }
         }
       }

openair2/LAYER2/NR_MAC_gNB/gNB_scheduler_srs.c

@@ -430,7 +430,7 @@ static void nr_configure_srs(nfapi_nr_srs_pdu_t *srs_pdu,
   srs_pdu->num_ant_ports = srs_resource->nrofSRS_Ports;
   srs_pdu->num_symbols = srs_resource->resourceMapping.nrofSymbols;
   srs_pdu->num_repetitions = srs_resource->resourceMapping.repetitionFactor;
-  srs_pdu->time_start_position = srs_resource->resourceMapping.startPosition;
+  srs_pdu->time_start_position = NR_NUMBER_OF_SYMBOLS_PER_SLOT - 1 - srs_resource->resourceMapping.startPosition;
   srs_pdu->config_index = srs_resource->freqHopping.c_SRS;
   srs_pdu->sequence_id = srs_resource->sequenceId;
   srs_pdu->bandwidth_index = srs_resource->freqHopping.b_SRS;
@@ -472,7 +472,7 @@ static void nr_configure_srs(nfapi_nr_srs_pdu_t *srs_pdu,
 
   // TODO properly use beam allocation
   uint16_t *vrb_map_UL = &RC.nrmac[module_id]->common_channels[CC_id].vrb_map_UL[0][buffer_index * MAX_BWP_SIZE];
-  uint64_t mask = SL_to_bitmap(13 - srs_pdu->time_start_position, srs_pdu->num_symbols);
+  uint64_t mask = SL_to_bitmap(srs_pdu->time_start_position, srs_pdu->num_symbols);
   for (int i = 0; i < srs_pdu->bwp_size; ++i)
     vrb_map_UL[i + srs_pdu->bwp_start] |= mask;
 }