MAC layer changes to process PTRS RRC values and validation

- Get RRC values from dedicated bandwidth part and process it
- Validate all settings in MAC layer and enable PTRS processing in PHY

openair2/LAYER2/NR_MAC_COMMON/nr_mac_common.c

@@ -1804,7 +1804,8 @@ void nr_get_tbs_dl(nfapi_nr_dl_tti_pdsch_pdu *pdsch_pdu,
   }
   uint8_t N_sh_symb = pdsch_rel15->NrOfSymbols;
   uint8_t Imcs = pdsch_rel15->mcsIndex[0];
-  uint16_t N_RE_prime = NR_NB_SC_PER_RB*N_sh_symb - N_PRB_DMRS - N_PRB_oh;
+  uint16_t dmrs_length = get_num_dmrs(pdsch_rel15->dlDmrsSymbPos);
+  uint16_t N_RE_prime = NR_NB_SC_PER_RB*N_sh_symb - N_PRB_DMRS*dmrs_length - N_PRB_oh;
   LOG_D(MAC, "N_RE_prime %d for %d symbols %d DMRS per PRB and %d overhead\n", N_RE_prime, N_sh_symb, N_PRB_DMRS, N_PRB_oh);
 
   uint16_t R;
@@ -1823,7 +1824,7 @@ void nr_get_tbs_dl(nfapi_nr_dl_tti_pdsch_pdu *pdsch_pdu,
                        R,
                        pdsch_rel15->rbSize,
                        N_sh_symb,
-		       N_PRB_DMRS, // FIXME // This should be multiplied by the number of dmrs symbols
+                       N_PRB_DMRS*dmrs_length, // FIXME // This should be multiplied by the number of dmrs symbols
                        N_PRB_oh,
                        tb_scaling,
 		       pdsch_rel15->nrOfLayers)>>3;
@@ -2705,6 +2706,8 @@ int16_t fill_dmrs_mask(NR_PDSCH_Config_t *pdsch_Config,int dmrs_TypeA_Position,i
 	if (NrOfSymbols < 13 && *dmrs_config->dmrs_AdditionalPosition!=NR_DMRS_DownlinkConfig__dmrs_AdditionalPosition_pos0) return(1<<l0 | 1<<8);
 	if (*dmrs_config->dmrs_AdditionalPosition!=NR_DMRS_DownlinkConfig__dmrs_AdditionalPosition_pos0) return(1<<l0);
 	if (*dmrs_config->dmrs_AdditionalPosition!=NR_DMRS_DownlinkConfig__dmrs_AdditionalPosition_pos1) return(1<<l0 | 1<<10);
+        if (*dmrs_config->dmrs_AdditionalPosition==NR_DMRS_DownlinkConfig__dmrs_AdditionalPosition_pos0) return(1<<l0);
+	if (*dmrs_config->dmrs_AdditionalPosition==NR_DMRS_DownlinkConfig__dmrs_AdditionalPosition_pos1) return(1<<l0 | 1<<10);
       }
     }
     else if (pdsch_Config->dmrs_DownlinkForPDSCH_MappingTypeB &&
@@ -2767,3 +2770,70 @@ int binomial(int n, int k) {
   return c;
 }
 
+/* extract PTRS values from RC and validate it based upon 38.214 5.1.6.3 */
+bool set_dl_ptrs_values(NR_PTRS_DownlinkConfig_t *ptrs_config,
+                        uint16_t rbSize,uint8_t mcsIndex, uint8_t mcsTable,
+                        uint8_t *K_ptrs, uint8_t *L_ptrs,
+                        uint8_t *portIndex,uint8_t *nERatio, uint8_t *reOffset,
+                        uint8_t NrOfSymbols)
+{
+  bool valid = true;
+
+  /* as defined in T 38.214 5.1.6.3 */
+  if(rbSize < 3)
+  {
+    valid = false;
+    return valid;
+  }
+  /* Check for Frequency Density values */
+  if(ptrs_config->frequencyDensity->list.count < 2)
+  {
+    /* Default value for K_PTRS = 2 as defined in T 38.214 5.1.6.3 */
+    *K_ptrs = 2;
+  }
+  else
+  {
+    *K_ptrs = get_K_ptrs(*ptrs_config->frequencyDensity->list.array[0],
+                         *ptrs_config->frequencyDensity->list.array[1],
+                         rbSize);
+  }
+  /* Check for time Density values */
+  if(ptrs_config->timeDensity->list.count < 3)
+  {
+    /* Default value for L_PTRS = 1 as defined in T 38.214 5.1.6.3 */
+       *L_ptrs = 1;
+  }
+  else
+  {
+    *L_ptrs = get_L_ptrs(*ptrs_config->timeDensity->list.array[0],
+                         *ptrs_config->timeDensity->list.array[1],
+                         *ptrs_config->timeDensity->list.array[2],
+                         mcsIndex,
+                         mcsTable);
+  }
+  *portIndex =*ptrs_config->epre_Ratio;
+  *nERatio = *ptrs_config->resourceElementOffset;
+  *reOffset  = 0;
+  
+  /* If either or both of the parameters PT-RS time density (LPT-RS) and PT-RS frequency density (KPT-RS), shown in Table
+   * 5.1.6.3-1 and Table 5.1.6.3-2, indicates that 'PT-RS not present', the UE shall assume that PT-RS is not present
+   */
+  if((*K_ptrs !=2  || *K_ptrs !=4 ) || (*L_ptrs !=0 || *L_ptrs !=1 || *L_ptrs !=2  ))
+  {
+    valid = false;
+    return valid;
+  }
+  /* PTRS is not present also :
+   * When the UE is receiving a PDSCH with allocation duration of 4 symbols and if LPT-RS is set to 4, the UE shall assume
+   * PT-RS is not transmitted
+   * When the UE is receiving a PDSCH with allocation duration of 2 symbols as defined in Clause 7.4.1.1.2 of [4, TS
+   * 38.211] and if LPT-RS is set to 2 or 4, the UE shall assume PT-RS is not transmitted.
+   */
+  if((NrOfSymbols == 4 && *L_ptrs ==2) || ((NrOfSymbols == 2 && *L_ptrs > 0)))
+  {
+    valid = false;
+    return valid;
+  }
+  //printf("[MAC] PTRS is set  K= %u L= %u\n", *K_ptrs,1<<*L_ptrs);
+  return valid;
+}

openair2/LAYER2/NR_MAC_COMMON/nr_mac_common.h

@@ -143,4 +143,10 @@ uint8_t get_L_ptrs(uint8_t mcs1, uint8_t mcs2, uint8_t mcs3, uint8_t I_mcs, uint
 uint8_t get_K_ptrs(uint16_t nrb0, uint16_t nrb1, uint16_t N_RB);
 
 int16_t get_N_RA_RB (int delta_f_RA_PRACH,int delta_f_PUSCH);
+
+bool set_dl_ptrs_values(NR_PTRS_DownlinkConfig_t *ptrs_config,
+                        uint16_t rbSize, uint8_t mcsIndex, uint8_t mcsTable,
+                        uint8_t *K_ptrs, uint8_t *L_ptrs,uint8_t *portIndex,
+                        uint8_t *nERatio,uint8_t *reOffset,
+                        uint8_t NrOfSymbols);
 #endif

openair2/LAYER2/NR_MAC_UE/nr_ue_procedures.c

@@ -2444,7 +2444,7 @@ int nr_ue_process_dci_indication_pdu(module_id_t module_id,int cc_id, int gNB_in
 int8_t nr_ue_process_dci(module_id_t module_id, int cc_id, uint8_t gNB_index, dci_pdu_rel15_t *dci, uint16_t rnti, uint32_t dci_format){
 
   int bwp_id = 1;
-
+  bool valid_ptrs_setup = 0;
   NR_UE_MAC_INST_t *mac = get_mac_inst(module_id);
   fapi_nr_dl_config_request_t *dl_config = &mac->dl_config_request;
   fapi_nr_ul_config_request_t *ul_config = &mac->ul_config_request;
@@ -3178,6 +3178,21 @@ int8_t nr_ue_process_dci(module_id_t module_id, int cc_id, uint8_t gNB_index, dc
     LOG_D(MAC,"(nr_ue_procedures.c) pdu_type=%d\n\n",dl_config->dl_config_list[dl_config->number_pdus].pdu_type);
             
     dl_config->number_pdus = dl_config->number_pdus + 1;
+    /* TODO same calculation for MCS table as done in UL */
+    dlsch_config_pdu_1_1->mcs_table = 0;
+    /*PTRS configuration */
+    if(mac->DLbwp[0]->bwp_Dedicated->pdsch_Config->choice.setup->dmrs_DownlinkForPDSCH_MappingTypeA->choice.setup->phaseTrackingRS != NULL)
+    {
+      valid_ptrs_setup = set_dl_ptrs_values(mac->DLbwp[0]->bwp_Dedicated->pdsch_Config->choice.setup->dmrs_DownlinkForPDSCH_MappingTypeA->choice.setup->phaseTrackingRS->choice.setup,
+                                            dlsch_config_pdu_1_1->number_rbs, dlsch_config_pdu_1_1->mcs, dlsch_config_pdu_1_1->mcs_table,
+                                            &dlsch_config_pdu_1_1->PTRSFreqDensity,&dlsch_config_pdu_1_1->PTRSTimeDensity,
+                                            &dlsch_config_pdu_1_1->PTRSPortIndex,&dlsch_config_pdu_1_1->nEpreRatioOfPDSCHToPTRS,
+                                            &dlsch_config_pdu_1_1->PTRSReOffset, dlsch_config_pdu_1_1->number_symbols);
+      if(valid_ptrs_setup==true)
+      {
+        dlsch_config_pdu_1_1->pduBitmap |= 0x1;
+      }
+    }
 
     break;
 

openair2/LAYER2/NR_MAC_gNB/gNB_scheduler_phytest.c

@@ -268,6 +268,7 @@ int configure_fapi_dl_pdu_phytest(int Mod_idP,
   int TBS;
   int bwp_id=1;
   int UE_id = 0;
+  bool valid_ptrs_setup = false;
 
   NR_UE_info_t *UE_info = &RC.nrmac[Mod_idP]->UE_info;
 
@@ -344,6 +345,20 @@ int configure_fapi_dl_pdu_phytest(int Mod_idP,
 						     scc->dmrs_TypeA_Position,
 						     pdsch_pdu_rel15->NrOfSymbols);
 
+  /* Check and validate PTRS values */
+  if(bwp->bwp_Dedicated->pdsch_Config->choice.setup->dmrs_DownlinkForPDSCH_MappingTypeA->choice.setup->phaseTrackingRS != NULL)
+  {
+    valid_ptrs_setup = set_dl_ptrs_values(bwp->bwp_Dedicated->pdsch_Config->choice.setup->dmrs_DownlinkForPDSCH_MappingTypeA->choice.setup->phaseTrackingRS->choice.setup,
+                                          pdsch_pdu_rel15->rbSize, pdsch_pdu_rel15->mcsIndex[0],
+                                          pdsch_pdu_rel15->mcsTable[0],
+                                          &pdsch_pdu_rel15->PTRSFreqDensity,&pdsch_pdu_rel15->PTRSTimeDensity,
+                                          &pdsch_pdu_rel15->PTRSPortIndex,&pdsch_pdu_rel15->nEpreRatioOfPDSCHToPTRS,
+                                          &pdsch_pdu_rel15->PTRSReOffset, pdsch_pdu_rel15->NrOfSymbols);
+    if(valid_ptrs_setup==true)
+    {
+      pdsch_pdu_rel15->pduBitmap |=0x1;
+    }
+  }
   dci_pdu_rel15_t *dci_pdu_rel15 = calloc(MAX_DCI_CORESET,sizeof(dci_pdu_rel15_t));
   
   // bwp indicator