taking into account maximum number of layers for PDSCH supported by the UE for TBSlbrm

openair2/LAYER2/NR_MAC_gNB/gNB_scheduler_dlsch.c

@@ -1113,7 +1113,12 @@ void post_process_dlsch(gNB_MAC_INST *nr_mac, post_process_pdsch_t *pdsch, NR_UE
   // TODO: verify the case where maxMIMO_Layers is NULL, in which case
   //       in principle maxMIMO_layers should be given by the maximum number of layers
   //       for PDSCH supported by the UE for the serving cell (5.4.2.1 of 38.212)
-  long maxMIMO_Layers = UE->sc_info.maxMIMO_Layers_PDSCH ? *UE->sc_info.maxMIMO_Layers_PDSCH : 1;
+  long ue_supp_nl = ue_supported_dl_layers(scc, UE->capability);
+  long maxMIMO_Layers = UE->sc_info.maxMIMO_Layers_PDSCH ? *UE->sc_info.maxMIMO_Layers_PDSCH : ue_supp_nl;
+  if (maxMIMO_Layers < 1) {
+    LOG_D(NR_MAC, "Both maxMIMO_Layers_PDSCH and UE supported layers are not present, defaulting to 1\n");
+    maxMIMO_Layers = 1;
+  }
   const int nl_tbslbrm = min(maxMIMO_Layers, 4);
   nfapi_nr_dl_tti_pdsch_pdu_rel15_t *pdsch_pdu = prepare_pdsch_pdu(dl_tti_pdsch_pdu,
                                                                    nr_mac,
@@ -1395,5 +1400,4 @@ void nr_schedule_ue_spec(module_id_t module_id,
 
   /* PREPROCESSOR */
   gNB_mac->pre_processor_dl(gNB_mac, &pdsch);
-
 }

openair2/LAYER2/NR_MAC_gNB/nr_radio_config.c

@@ -585,22 +585,13 @@ static void config_csiim(int do_csirs,
 }
 
 
-void set_dl_maxmimolayers(NR_PDSCH_ServingCellConfig_t *pdsch_servingcellconfig,
-                          const NR_ServingCellConfigCommon_t *scc,
-                          const NR_UE_NR_Capability_t *uecap,
-                          int maxMIMO_layers)
+long ue_supported_dl_layers(const NR_ServingCellConfigCommon_t *scc, const NR_UE_NR_Capability_t *uecap)
 {
-  if(!pdsch_servingcellconfig->ext1)
-    pdsch_servingcellconfig->ext1=calloc(1,sizeof(*pdsch_servingcellconfig->ext1));
-  if(!pdsch_servingcellconfig->ext1->maxMIMO_Layers)
-    pdsch_servingcellconfig->ext1->maxMIMO_Layers = calloc(1,sizeof(*pdsch_servingcellconfig->ext1->maxMIMO_Layers));
-
   NR_SCS_SpecificCarrier_t *scs_carrier = scc->downlinkConfigCommon->frequencyInfoDL->scs_SpecificCarrierList.list.array[0];
   int band = *scc->downlinkConfigCommon->frequencyInfoDL->frequencyBandList.list.array[0];
   const frequency_range_t freq_range = get_freq_range_from_band(band);
   const int scs = scs_carrier->subcarrierSpacing;
   const int bw_size = scs_carrier->carrierBandwidth;
-
   NR_FeatureSets_t *fs = uecap ? uecap->featureSets : NULL;
   if (fs) {
     const int bw_mhz = get_supported_bw_mhz(freq_range, get_supported_band_index(scs, freq_range, bw_size));
@@ -610,16 +601,29 @@ void set_dl_maxmimolayers(NR_PDSCH_ServingCellConfig_t *pdsch_servingcellconfig,
       if (scs == dl_fs->supportedSubcarrierSpacingDL &&
           supported_bw_comparison(bw_mhz, &dl_fs->supportedBandwidthDL, dl_fs->channelBW_90mhz) &&
           dl_fs->maxNumberMIMO_LayersPDSCH) {
-        long ue_supported_layers = (2 << *dl_fs->maxNumberMIMO_LayersPDSCH);
-        if (maxMIMO_layers == -1) 
-          *pdsch_servingcellconfig->ext1->maxMIMO_Layers = NR_MAX_SUPPORTED_DL_LAYERS < ue_supported_layers ? NR_MAX_SUPPORTED_DL_LAYERS : ue_supported_layers;
-        else 
-          *pdsch_servingcellconfig->ext1->maxMIMO_Layers = maxMIMO_layers < ue_supported_layers ? maxMIMO_layers : ue_supported_layers;
-        return;
+        return (2 << *dl_fs->maxNumberMIMO_LayersPDSCH);
       }
     }
   }
-  *pdsch_servingcellconfig->ext1->maxMIMO_Layers = 2;
+  return -1;
+}
+
+static void set_dl_maxmimolayers(NR_PDSCH_ServingCellConfig_t *pdsch_servingcellconfig,
+                                 const NR_ServingCellConfigCommon_t *scc,
+                                 const NR_UE_NR_Capability_t *uecap,
+                                 int maxMIMO_layers)
+{
+  if(!pdsch_servingcellconfig->ext1)
+    pdsch_servingcellconfig->ext1 = calloc(1, sizeof(*pdsch_servingcellconfig->ext1));
+  if(!pdsch_servingcellconfig->ext1->maxMIMO_Layers)
+    pdsch_servingcellconfig->ext1->maxMIMO_Layers = calloc(1, sizeof(*pdsch_servingcellconfig->ext1->maxMIMO_Layers));
+
+  long l = ue_supported_dl_layers(scc, uecap);
+  long ue_supported_layers = l > 1 ? l : 2; // min UE supported layers = 2
+  if (maxMIMO_layers == -1) 
+    *pdsch_servingcellconfig->ext1->maxMIMO_Layers = min(NR_MAX_SUPPORTED_DL_LAYERS, ue_supported_layers);
+  else 
+    *pdsch_servingcellconfig->ext1->maxMIMO_Layers = min(maxMIMO_layers, ue_supported_layers);
 }
 
 // TODO: Implement to b_SRS = 1 and b_SRS = 2

openair2/LAYER2/NR_MAC_gNB/nr_radio_config.h

@@ -134,5 +134,5 @@ NR_CellGroupConfig_t * update_cellGroupConfig_for_BWP_switch(NR_CellGroupConfig_
 NR_MeasurementTimingConfiguration_t *get_nr_mtc(uint8_t *buf, uint32_t len);
 measgap_config_t create_measgap_config(const NR_MeasurementTimingConfiguration_t *mtc, int scs, int min_rxtxtime);
 int encode_measgap_config(const measgap_config_t *c, uint8_t *buf);
-
+long ue_supported_dl_layers(const NR_ServingCellConfigCommon_t *scc, const NR_UE_NR_Capability_t *uecap);
 #endif