handling dl dmrs ports at mac and other modifications for semi static parameters for dlsch

openair1/SIMULATION/NR_PHY/dlsim.c

@@ -273,8 +273,8 @@ void nr_dlsim_preprocessor(module_id_t module_id,
   /* the following might override the table that is mandated by RRC
    * configuration */
   ps->mcsTableIdx = g_mcsTableIdx;
+  ps->nrOfLayers = g_nrOfLayers;
 
-  sched_pdsch->nrOfLayers = g_nrOfLayers;
   sched_pdsch->Qm = nr_get_Qm_dl(sched_pdsch->mcs, ps->mcsTableIdx);
   sched_pdsch->R = nr_get_code_rate_dl(sched_pdsch->mcs, ps->mcsTableIdx);
   sched_pdsch->tb_size = nr_compute_tbs(sched_pdsch->Qm,

openair2/LAYER2/NR_MAC_gNB/gNB_scheduler_dlsch.c

@@ -453,8 +453,6 @@ bool allocate_dl_retransmission(module_id_t module_id,
   int rbStart = NRRIV2PRBOFFSET(genericParameters->locationAndBandwidth, MAX_BWP_SIZE);
 
   NR_pdsch_semi_static_t *ps = &sched_ctrl->pdsch_semi_static;
-  const long f = sched_ctrl->search_space->searchSpaceType->choice.ue_Specific->dci_Formats;
-  const uint8_t num_dmrs_cdm_grps_no_data = sched_ctrl->active_bwp ? (f ? 1 : (ps->nrOfSymbols == 2 ? 1 : 2)) : (ps->nrOfSymbols == 2 ? 1 : 2);
 
   int rbSize = 0;
   const int tda = sched_ctrl->active_bwp ? RC.nrmac[module_id]->preferred_dl_tda[sched_ctrl->active_bwp->bwp_Id][slot] : 1;
@@ -474,9 +472,8 @@ bool allocate_dl_retransmission(module_id_t module_id,
     }
     /* check whether we need to switch the TDA allocation since the last
      * (re-)transmission */
-    if (ps->time_domain_allocation != tda || ps->numDmrsCdmGrpsNoData != num_dmrs_cdm_grps_no_data)
-      nr_set_pdsch_semi_static(
-          scc, UE_info->CellGroup[UE_id], sched_ctrl->active_bwp, tda, num_dmrs_cdm_grps_no_data, ps);
+    if (ps->time_domain_allocation != tda || ps->nrOfLayers != UE_info->layers[UE_id])
+      nr_set_pdsch_semi_static(scc, UE_info->CellGroup[UE_id], sched_ctrl->active_bwp, tda, UE_info->layers[UE_id], sched_ctrl, ps);
   } else {
     /* the retransmission will use a different time domain allocation, check
      * that we have enough resources */
@@ -485,13 +482,12 @@ bool allocate_dl_retransmission(module_id_t module_id,
     while (rbStart + rbSize < bwpSize && rballoc_mask[rbStart + rbSize])
       rbSize++;
     NR_pdsch_semi_static_t temp_ps;
-    nr_set_pdsch_semi_static(
-        scc, UE_info->CellGroup[UE_id], sched_ctrl->active_bwp, tda, num_dmrs_cdm_grps_no_data, &temp_ps);
+    nr_set_pdsch_semi_static(scc, UE_info->CellGroup[UE_id], sched_ctrl->active_bwp, tda, UE_info->layers[UE_id], sched_ctrl, &temp_ps);
     uint32_t new_tbs;
     uint16_t new_rbSize;
     bool success = nr_find_nb_rb(retInfo->Qm,
                                  retInfo->R,
-                                 retInfo->nrOfLayers,
+                                 temp_ps.nrOfLayers,
                                  temp_ps.nrOfSymbols,
                                  temp_ps.N_PRB_DMRS * temp_ps.N_DMRS_SLOT,
                                  retInfo->tb_size,
@@ -603,7 +599,7 @@ void pf_dl(module_id_t module_id,
 
       /* Calculate coeff */
       set_dl_mcs(sched_pdsch,sched_ctrl,ps->mcsTableIdx);
-      set_dl_nrOfLayers(sched_pdsch,sched_ctrl);
+      UE_info->layers[UE_id] = set_dl_nrOfLayers(sched_ctrl);
       const uint8_t Qm = nr_get_Qm_dl(sched_pdsch->mcs, ps->mcsTableIdx);
       const uint16_t R = nr_get_code_rate_dl(sched_pdsch->mcs, ps->mcsTableIdx);
       uint32_t tbs = nr_compute_tbs(Qm,
@@ -613,7 +609,7 @@ void pf_dl(module_id_t module_id,
                                     0, /* N_PRB_DMRS * N_DMRS_SLOT */
                                     0 /* N_PRB_oh, 0 for initialBWP */,
                                     0 /* tb_scaling */,
-                                    sched_pdsch->nrOfLayers) >> 3;
+                                    UE_info->layers[UE_id]) >> 3;
       coeff_ue[UE_id] = (float) tbs / thr_ue[UE_id];
       LOG_D(NR_MAC,"b %d, thr_ue[%d] %f, tbs %d, coeff_ue[%d] %f\n",
             b, UE_id, thr_ue[UE_id], tbs, UE_id, coeff_ue[UE_id]);
@@ -691,10 +687,9 @@ void pf_dl(module_id_t module_id,
     const int tda = sched_ctrl->active_bwp ? RC.nrmac[module_id]->preferred_dl_tda[sched_ctrl->active_bwp->bwp_Id][slot] : 1;
     NR_sched_pdsch_t *sched_pdsch = &sched_ctrl->sched_pdsch;
     NR_pdsch_semi_static_t *ps = &sched_ctrl->pdsch_semi_static;
-    const long f = sched_ctrl->search_space->searchSpaceType->choice.ue_Specific->dci_Formats;
-    const uint8_t num_dmrs_cdm_grps_no_data = sched_ctrl->active_bwp ? (f ? 1 : (ps->nrOfSymbols == 2 ? 1 : 2)) : (ps->nrOfSymbols == 2 ? 1 : 2);
-    if (ps->time_domain_allocation != tda || ps->numDmrsCdmGrpsNoData != num_dmrs_cdm_grps_no_data)
-      nr_set_pdsch_semi_static(scc, UE_info->CellGroup[UE_id], sched_ctrl->active_bwp, tda, num_dmrs_cdm_grps_no_data, ps);
+    if (ps->nrOfLayers != UE_info->layers[UE_id] ||
+        ps->time_domain_allocation != tda)
+      nr_set_pdsch_semi_static(scc, UE_info->CellGroup[UE_id], sched_ctrl->active_bwp, tda, UE_info->layers[UE_id], sched_ctrl, ps);
     sched_pdsch->Qm = nr_get_Qm_dl(sched_pdsch->mcs, ps->mcsTableIdx);
     sched_pdsch->R = nr_get_code_rate_dl(sched_pdsch->mcs, ps->mcsTableIdx);
     sched_pdsch->pucch_allocation = alloc;
@@ -704,7 +699,7 @@ void pf_dl(module_id_t module_id,
                  + 2 * (frame == (sched_ctrl->ta_frame + 10) % 1024);
     nr_find_nb_rb(sched_pdsch->Qm,
                   sched_pdsch->R,
-                  sched_pdsch->nrOfLayers,
+                  ps->nrOfLayers,
                   ps->nrOfSymbols,
                   ps->N_PRB_DMRS * ps->N_DMRS_SLOT,
                   sched_ctrl->num_total_bytes + oh,
@@ -829,17 +824,17 @@ void nr_schedule_ue_spec(module_id_t module_id,
 
     const rnti_t rnti = UE_info->rnti[UE_id];
 
-    /* POST processing */
-    const uint8_t nrOfLayers = sched_pdsch->nrOfLayers;
-    const uint16_t R = sched_pdsch->R;
-    const uint8_t Qm = sched_pdsch->Qm;
-    const uint32_t TBS = sched_pdsch->tb_size;
-
     /* pre-computed PDSCH values that only change if time domain
      * allocation/DMRS parameters change. Updated in the preprocessor through
      * nr_set_pdsch_semi_static() */
     NR_pdsch_semi_static_t *ps = &sched_ctrl->pdsch_semi_static;
 
+    /* POST processing */
+    const uint8_t nrOfLayers = ps->nrOfLayers;
+    const uint16_t R = sched_pdsch->R;
+    const uint8_t Qm = sched_pdsch->Qm;
+    const uint32_t TBS = sched_pdsch->tb_size;
+
     int8_t current_harq_pid = sched_pdsch->dl_harq_pid;
     if (current_harq_pid < 0) {
       /* PP has not selected a specific HARQ Process, get a new one */
@@ -949,7 +944,7 @@ void nr_schedule_ue_spec(module_id_t module_id,
     pdsch_pdu->dlDmrsScramblingId = *scc->physCellId;
     pdsch_pdu->SCID = 0;
     pdsch_pdu->numDmrsCdmGrpsNoData = ps->numDmrsCdmGrpsNoData;
-    pdsch_pdu->dmrsPorts = 1;
+    pdsch_pdu->dmrsPorts = (1<<nrOfLayers)-1;  // FIXME with a better implementation
 
     // Pdsch Allocation in frequency domain
     pdsch_pdu->resourceAlloc = 1;
@@ -1031,7 +1026,7 @@ void nr_schedule_ue_spec(module_id_t module_id,
     dci_payload.tpc = sched_ctrl->tpc1; // TPC for PUCCH: table 7.2.1-1 in 38.213
     dci_payload.pucch_resource_indicator = pucch->resource_indicator;
     dci_payload.pdsch_to_harq_feedback_timing_indicator.val = pucch->timing_indicator; // PDSCH to HARQ TI
-    dci_payload.antenna_ports.val = 0;  // nb of cdm groups w/o data 1 and dmrs port 0
+    dci_payload.antenna_ports.val = ps->dmrs_ports_id;
     dci_payload.dmrs_sequence_initialization.val = pdsch_pdu->SCID;
     LOG_D(NR_MAC,
           "%4d.%2d DCI type 1 payload: freq_alloc %d (%d,%d,%d), "

openair2/LAYER2/NR_MAC_gNB/gNB_scheduler_phytest.c

@@ -365,12 +365,10 @@ void nr_preprocessor_phytest(module_id_t module_id,
   sched_pdsch->rbStart = rbStart;
   sched_pdsch->rbSize = rbSize;
   const int tda = sched_ctrl->active_bwp ? RC.nrmac[module_id]->preferred_dl_tda[sched_ctrl->active_bwp->bwp_Id][slot] : 1;
-  const uint8_t num_dmrs_cdm_grps_no_data = 1;
-  if (ps->time_domain_allocation != tda || ps->numDmrsCdmGrpsNoData != num_dmrs_cdm_grps_no_data)
-    nr_set_pdsch_semi_static(
-        scc, UE_info->CellGroup[UE_id], sched_ctrl->active_bwp, tda, num_dmrs_cdm_grps_no_data, ps);
+  int nrOfLayers = 1;
+  if (ps->time_domain_allocation != tda || ps->nrOfLayers != nrOfLayers)
+    nr_set_pdsch_semi_static(scc, UE_info->CellGroup[UE_id], sched_ctrl->active_bwp, tda, nrOfLayers, sched_ctrl, ps);
 
-  sched_pdsch->nrOfLayers = 1;
   sched_pdsch->mcs = target_dl_mcs;
   sched_pdsch->Qm = nr_get_Qm_dl(sched_pdsch->mcs, ps->mcsTableIdx);
   sched_pdsch->R = nr_get_code_rate_dl(sched_pdsch->mcs, ps->mcsTableIdx);
@@ -381,7 +379,7 @@ void nr_preprocessor_phytest(module_id_t module_id,
                                         ps->N_PRB_DMRS * ps->N_DMRS_SLOT,
                                         0 /* N_PRB_oh, 0 for initialBWP */,
                                         0 /* tb_scaling */,
-                                        sched_pdsch->nrOfLayers)
+                                        ps->nrOfLayers)
                          >> 3;
 
   /* get the PID of a HARQ process awaiting retransmission, or -1 otherwise */

openair2/LAYER2/NR_MAC_gNB/gNB_scheduler_primitives.c

@@ -137,12 +137,11 @@ static inline uint8_t get_max_cces(uint8_t scs) {
 }
 
 
-void set_dl_nrOfLayers(NR_sched_pdsch_t *sched_pdsch,
-                       NR_UE_sched_ctrl_t *sched_ctrl) {
+uint8_t set_dl_nrOfLayers(NR_UE_sched_ctrl_t *sched_ctrl) {
 
-  // for now this should be enough
+  // TODO check this but it should be enough for now
   // if there is not csi report RI is 0 from initialization
-  sched_pdsch->nrOfLayers = sched_ctrl->CSI_report.cri_ri_li_pmi_cqi_report.ri + 1;
+  return (sched_ctrl->CSI_report.cri_ri_li_pmi_cqi_report.ri + 1);
 
 }
 
@@ -193,6 +192,36 @@ void set_dl_mcs(NR_sched_pdsch_t *sched_pdsch,
   }
 }
 
+void set_dl_dmrs_ports(NR_pdsch_semi_static_t *ps) {
+
+  //TODO first basic implementation of dmrs port selection
+  //     only vaild for a single codeword
+  //     for now it assumes a selection of Nl consecutive dmrs ports
+  //     and a single front loaded symbol
+  //     dmrs_ports_id is the index of Tables 7.3.1.2.2-1/2/3/4
+
+  switch (ps->nrOfLayers) {
+    case 1:
+      ps->dmrs_ports_id = 0;
+      ps->numDmrsCdmGrpsNoData = 1;
+      break;
+    case 2:
+      ps->dmrs_ports_id = 2;
+      ps->numDmrsCdmGrpsNoData = 1;
+      break;
+    case 3:
+      ps->dmrs_ports_id = 9;
+      ps->numDmrsCdmGrpsNoData = 2;
+      break;
+    case 4:
+      ps->dmrs_ports_id = 10;
+      ps->numDmrsCdmGrpsNoData = 2;
+      break;
+    default:
+      AssertFatal(1==0,"Number of layers %d\n not supported or not valid\n",ps->nrOfLayers);
+  }
+}
+
 NR_ControlResourceSet_t *get_coreset(NR_ServingCellConfigCommon_t *scc,
                                      NR_BWP_Downlink_t *bwp,
                                      NR_SearchSpace_t *ss,
@@ -341,20 +370,11 @@ void nr_set_pdsch_semi_static(const NR_ServingCellConfigCommon_t *scc,
                               const NR_CellGroupConfig_t *secondaryCellGroup,
                               const NR_BWP_Downlink_t *bwp,
                               int tda,
-                              uint8_t num_dmrs_cdm_grps_no_data,
+                              uint8_t layers,
+                              NR_UE_sched_ctrl_t *sched_ctrl,
                               NR_pdsch_semi_static_t *ps)
 {
-  ps->time_domain_allocation = tda;
 
-  const struct NR_PDSCH_TimeDomainResourceAllocationList *tdaList = bwp ?
-      bwp->bwp_Common->pdsch_ConfigCommon->choice.setup->pdsch_TimeDomainAllocationList :
-      scc->downlinkConfigCommon->initialDownlinkBWP->pdsch_ConfigCommon->choice.setup->pdsch_TimeDomainAllocationList;
-  AssertFatal(tda < tdaList->list.count, "time_domain_allocation %d>=%d\n", tda, tdaList->list.count);
-  const int mapping_type = tdaList->list.array[tda]->mappingType;
-  const int startSymbolAndLength = tdaList->list.array[tda]->startSymbolAndLength;
-  SLIV2SL(startSymbolAndLength, &ps->startSymbolIndex, &ps->nrOfSymbols);
-
-  ps->mcsTableIdx = 0;
   if (bwp &&
       bwp->bwp_Dedicated &&
       bwp->bwp_Dedicated->pdsch_Config &&
@@ -367,14 +387,57 @@ void nr_set_pdsch_semi_static(const NR_ServingCellConfigCommon_t *scc,
   }
   else ps->mcsTableIdx = 0;
 
-  ps->numDmrsCdmGrpsNoData = num_dmrs_cdm_grps_no_data;
-  ps->dmrsConfigType = bwp!=NULL ? (bwp->bwp_Dedicated->pdsch_Config->choice.setup->dmrs_DownlinkForPDSCH_MappingTypeA->choice.setup->dmrs_Type == NULL ? 0 : 1) : 0;
+  NR_PDSCH_Config_t *pdsch_Config;
+  if (bwp &&
+      bwp->bwp_Dedicated &&
+      bwp->bwp_Dedicated->pdsch_Config &&
+      bwp->bwp_Dedicated->pdsch_Config->choice.setup)
+    pdsch_Config = bwp->bwp_Dedicated->pdsch_Config->choice.setup;
+  else
+    pdsch_Config = NULL;
+
+  if (ps->time_domain_allocation != tda) {
+    ps->time_domain_allocation = tda;
+    const struct NR_PDSCH_TimeDomainResourceAllocationList *tdaList = bwp ?
+      bwp->bwp_Common->pdsch_ConfigCommon->choice.setup->pdsch_TimeDomainAllocationList :
+      scc->downlinkConfigCommon->initialDownlinkBWP->pdsch_ConfigCommon->choice.setup->pdsch_TimeDomainAllocationList;
+    AssertFatal(tda < tdaList->list.count, "time_domain_allocation %d>=%d\n", tda, tdaList->list.count);
+    ps->mapping_type = tdaList->list.array[tda]->mappingType;
+    if (pdsch_Config) {
+      if (ps->mapping_type == NR_PDSCH_TimeDomainResourceAllocation__mappingType_typeB)
+        ps->dmrsConfigType = pdsch_Config->dmrs_DownlinkForPDSCH_MappingTypeB->choice.setup->dmrs_Type == NULL ? 0 : 1;
+      else
+        ps->dmrsConfigType = pdsch_Config->dmrs_DownlinkForPDSCH_MappingTypeA->choice.setup->dmrs_Type == NULL ? 0 : 1;
+    }
+    else
+      ps->dmrsConfigType = NFAPI_NR_DMRS_TYPE1;
+    const int startSymbolAndLength = tdaList->list.array[tda]->startSymbolAndLength;
+    SLIV2SL(startSymbolAndLength, &ps->startSymbolIndex, &ps->nrOfSymbols);
+    ps->dl_dmrs_symb_pos = fill_dmrs_mask(pdsch_Config, scc->dmrs_TypeA_Position, ps->nrOfSymbols, ps->startSymbolIndex, ps->mapping_type);
+    ps->N_DMRS_SLOT = get_num_dmrs(ps->dl_dmrs_symb_pos);
+  }
+
+  const long dci_format = sched_ctrl->search_space->searchSpaceType->choice.ue_Specific->dci_Formats;
+  if (dci_format == NR_SearchSpace__searchSpaceType__ue_Specific__dci_Formats_formats0_0_And_1_0 ||
+      pdsch_Config == NULL) {
+    if (ps->nrOfSymbols == 2 && ps->mapping_type == NR_PDSCH_TimeDomainResourceAllocation__mappingType_typeB)
+      ps->numDmrsCdmGrpsNoData = 1;
+    else {
+      if (ps->dmrsConfigType == NFAPI_NR_DMRS_TYPE1)
+        ps->numDmrsCdmGrpsNoData = 2;
+      else
+        ps->numDmrsCdmGrpsNoData = 3;
+    }
+    ps->dmrs_ports_id = 0;
+  }
+  else {
+    if (ps->nrOfLayers != layers) {
+      ps->nrOfLayers = layers;
+      set_dl_dmrs_ports(ps);
+    }
+  }
 
-  // if no data in dmrs cdm group is 1 only even REs have no data
-  // if no data in dmrs cdm group is 2 both odd and even REs have no data
-  ps->N_PRB_DMRS = num_dmrs_cdm_grps_no_data * (ps->dmrsConfigType == NFAPI_NR_DMRS_TYPE1 ? 6 : 4);
-  ps->dl_dmrs_symb_pos = fill_dmrs_mask(bwp ? bwp->bwp_Dedicated->pdsch_Config->choice.setup : NULL, scc->dmrs_TypeA_Position, ps->nrOfSymbols, ps->startSymbolIndex, mapping_type);
-  ps->N_DMRS_SLOT = get_num_dmrs(ps->dl_dmrs_symb_pos);
+  ps->N_PRB_DMRS = ps->numDmrsCdmGrpsNoData * (ps->dmrsConfigType == NFAPI_NR_DMRS_TYPE1 ? 6 : 4);
 }
 
 void nr_set_pusch_semi_static(const NR_ServingCellConfigCommon_t *scc,
@@ -671,7 +734,7 @@ void nr_configure_css_dci_initial(nfapi_nr_dl_tti_pdcch_pdu_rel15_t* pdcch_pdu,
 }
 
 void config_uldci(const NR_BWP_Uplink_t *ubwp,
-		              const NR_ServingCellConfigCommon_t *scc,
+                  const NR_ServingCellConfigCommon_t *scc,
                   const nfapi_nr_pusch_pdu_t *pusch_pdu,
                   dci_pdu_rel15_t *dci_pdu_rel15,
                   int dci_format,
@@ -810,15 +873,15 @@ void nr_configure_pdcch(nfapi_nr_dl_tti_pdcch_pdu_rel15_t *pdcch_pdu,
 
 // This function configures pucch pdu fapi structure
 void nr_configure_pucch(nfapi_nr_pucch_pdu_t* pucch_pdu,
-			                  NR_ServingCellConfigCommon_t *scc,
-			                  NR_CellGroupConfig_t *CellGroup,
-			                  NR_BWP_Uplink_t *bwp,
+                        NR_ServingCellConfigCommon_t *scc,
+                        NR_CellGroupConfig_t *CellGroup,
+                        NR_BWP_Uplink_t *bwp,
                         uint16_t rnti,
                         uint8_t pucch_resource,
                         uint16_t O_csi,
                         uint16_t O_ack,
                         uint8_t O_sr,
-			                  int r_pucch) {
+                        int r_pucch) {
 
   NR_PUCCH_Config_t *pucch_Config;
   NR_PUCCH_Resource_t *pucchres;

openair2/LAYER2/NR_MAC_gNB/mac_proto.h

@@ -230,7 +230,7 @@ void nr_configure_pucch(nfapi_nr_pucch_pdu_t* pucch_pdu,
                         uint16_t O_csi,
                         uint16_t O_ack,
                         uint8_t O_sr,
-			                  int r_pucch);
+                        int r_pucch);
 
 void find_search_space(int ss_type,
                        NR_BWP_Downlink_t *bwp,
@@ -273,7 +273,8 @@ void nr_set_pdsch_semi_static(const NR_ServingCellConfigCommon_t *scc,
                               const NR_CellGroupConfig_t *secondaryCellGroup,
                               const NR_BWP_Downlink_t *bwp,
                               int tda,
-                              uint8_t num_dmrs_cdm_grps_no_data,
+                              uint8_t layers,
+                              NR_UE_sched_ctrl_t *sched_ctrl,
                               NR_pdsch_semi_static_t *ps);
 
 void nr_set_pusch_semi_static(const NR_ServingCellConfigCommon_t *scc,
@@ -415,12 +416,13 @@ int16_t ssb_index_from_prach(module_id_t module_idP,
 
 void find_SSB_and_RO_available(module_id_t module_idP);
 
+void set_dl_dmrs_ports(NR_pdsch_semi_static_t *ps);
+
 void set_dl_mcs(NR_sched_pdsch_t *sched_pdsch,
                 NR_UE_sched_ctrl_t *sched_ctrl,
                 uint8_t mcs_table_idx);
 
-void set_dl_nrOfLayers(NR_sched_pdsch_t *sched_pdsch,
-                       NR_UE_sched_ctrl_t *sched_ctrl);
+uint8_t set_dl_nrOfLayers(NR_UE_sched_ctrl_t *sched_ctrl);
 
 void calculate_preferred_dl_tda(module_id_t module_id, const NR_BWP_Downlink_t *bwp);
 void calculate_preferred_ul_tda(module_id_t module_id, const NR_BWP_Uplink_t *ubwp);

openair2/LAYER2/NR_MAC_gNB/nr_mac_gNB.h

@@ -362,12 +362,12 @@ typedef struct NR_sched_pusch {
 typedef struct NR_pdsch_semi_static {
   int time_domain_allocation;
   uint8_t numDmrsCdmGrpsNoData;
-
+  int mapping_type;
   int startSymbolIndex;
   int nrOfSymbols;
-
+  uint8_t nrOfLayers;
   uint8_t mcsTableIdx;
-
+  uint8_t dmrs_ports_id;
   uint8_t N_PRB_DMRS;
   uint8_t N_DMRS_SLOT;
   uint16_t dl_dmrs_symb_pos;
@@ -383,7 +383,6 @@ typedef struct NR_sched_pdsch {
   uint8_t mcs;
 
   /// TBS-related info
-  uint8_t nrOfLayers;
   uint16_t R;
   uint8_t Qm;
   uint32_t tb_size;
@@ -626,7 +625,7 @@ typedef struct {
   NR_mac_stats_t mac_stats[MAX_MOBILES_PER_GNB];
   NR_list_t list;
   int num_UEs;
-
+  int layers[MAX_MOBILES_PER_GNB];
   bool active[MAX_MOBILES_PER_GNB];
   rnti_t rnti[MAX_MOBILES_PER_GNB];
   NR_CellGroupConfig_t *CellGroup[MAX_MOBILES_PER_GNB];