Bugfix in DMRS configuration at UE side:

- DM-RS type {1,2} was wrongly assigned to {1,2} instead of {0,1}
- Num DM-RS CDM groups without data is now taken into account in mthread
  decoding function
- number of DM-RS CDM groups without data for format 1_0 according to 5.1.6.2
  3GPP TS 38.214 version 15.9.0 Release 15:
-- the UE shall assume the number of DM-RS CDM groups without data is:
-- 1 (CDM group 0) for the case of PDSCH with allocation duration of 2 symb
-- 2 (CDM group {0,1}) for all other cases.

openair1/PHY/NR_UE_TRANSPORT/nr_dlsch_decoding.c

@@ -266,7 +266,7 @@ uint32_t nr_dlsch_decoding(PHY_VARS_NR_UE *phy_vars_ue,
   double Coderate;// = 0.0;
 
   uint8_t dmrs_Type = harq_process->dmrsConfigType;
-  AssertFatal(dmrs_Type == 1 || dmrs_Type == 2,"Illegal dmrs_type %d\n",dmrs_Type);
+  AssertFatal(dmrs_Type == 0 || dmrs_Type == 1, "Illegal dmrs_type %d\n", dmrs_Type);
   uint8_t nb_re_dmrs;
   if (dmrs_Type==NFAPI_NR_DMRS_TYPE1) {
     nb_re_dmrs = 6*harq_process->n_dmrs_cdm_groups;
@@ -811,7 +811,12 @@ uint32_t  nr_dlsch_decoding_mthread(PHY_VARS_NR_UE *phy_vars_ue,
   //nfapi_nr_config_request_t *cfg = &phy_vars_ue->nrUE_config;
   //uint8_t dmrs_type = cfg->pdsch_config.dmrs_type.value;
 
-  uint8_t nb_re_dmrs = 12;//(dmrs_type==1)?6:4;
+  uint8_t nb_re_dmrs;
+  if (dmrs_Type == NFAPI_NR_DMRS_TYPE1)
+    nb_re_dmrs = 6*harq_process->n_dmrs_cdm_groups;
+  else
+    nb_re_dmrs = 4*harq_process->n_dmrs_cdm_groups;
+
   uint16_t length_dmrs = get_num_dmrs(dl_config_pdu->dlDmrsSymbPos); 
 
   uint32_t i,j;

openair2/LAYER2/NR_MAC_UE/nr_ue_procedures.c

@@ -2749,7 +2749,12 @@ int8_t nr_ue_process_dci(module_id_t module_id, int cc_id, uint8_t gNB_index, dc
     dlsch_config_pdu_1_0->dlDmrsSymbPos = fill_dmrs_mask(pdsch_config,
 							 mac->scc->dmrs_TypeA_Position,
 							 dlsch_config_pdu_1_0->number_symbols);
-    dlsch_config_pdu_1_0->dmrsConfigType = mac->DLbwp[0]->bwp_Dedicated->pdsch_Config->choice.setup->dmrs_DownlinkForPDSCH_MappingTypeA->choice.setup->dmrs_Type == NULL ? 1 : 2;
+    dlsch_config_pdu_1_0->dmrsConfigType = mac->DLbwp[0]->bwp_Dedicated->pdsch_Config->choice.setup->dmrs_DownlinkForPDSCH_MappingTypeA->choice.setup->dmrs_Type == NULL ? 0 : 1;
+    /* number of DM-RS CDM groups without data according to subclause 5.1.6.2 of 3GPP TS 38.214 version 15.9.0 Release 15 */
+    if (dlsch_config_pdu_1_0->number_symbols == 2)
+      dlsch_config_pdu_1_0->n_dmrs_cdm_groups = 1;
+    else
+      dlsch_config_pdu_1_0->n_dmrs_cdm_groups = 2;
     /* VRB_TO_PRB_MAPPING */
     dlsch_config_pdu_1_0->vrb_to_prb_mapping = (dci->vrb_to_prb_mapping.val == 0) ? vrb_to_prb_mapping_non_interleaved:vrb_to_prb_mapping_interleaved;
     /* MCS */
@@ -2869,7 +2874,7 @@ int8_t nr_ue_process_dci(module_id_t module_id, int cc_id, uint8_t gNB_index, dc
     dlsch_config_pdu_1_1->dlDmrsSymbPos = fill_dmrs_mask(pdsch_config,
 							 mac->scc->dmrs_TypeA_Position,
 							 dlsch_config_pdu_1_1->number_symbols);
-    dlsch_config_pdu_1_1->dmrsConfigType = mac->DLbwp[0]->bwp_Dedicated->pdsch_Config->choice.setup->dmrs_DownlinkForPDSCH_MappingTypeA->choice.setup->dmrs_Type == NULL ? 1 : 2;
+    dlsch_config_pdu_1_1->dmrsConfigType = mac->DLbwp[0]->bwp_Dedicated->pdsch_Config->choice.setup->dmrs_DownlinkForPDSCH_MappingTypeA->choice.setup->dmrs_Type == NULL ? 0 : 1;
     /* VRB_TO_PRB_MAPPING */
     if (mac->phy_config.config_req.dl_bwp_dedicated.pdsch_config_dedicated.resource_allocation != 0)
       dlsch_config_pdu_1_1->vrb_to_prb_mapping = (dci->vrb_to_prb_mapping.val == 0) ? vrb_to_prb_mapping_non_interleaved:vrb_to_prb_mapping_interleaved;