adding srs estimation at secondary gNB

openair2/LAYER2/NR_MAC_gNB/config.c

@@ -46,6 +46,7 @@
 #include "openair1/PHY/defs_gNB.h"
 
 #include "NR_MIB.h"
+#include "RRC/NR/nr_rrc_config.h"
 #include "LAYER2/NR_MAC_COMMON/nr_mac_common.h"
 #include "../../../../nfapi/oai_integration/vendor_ext.h"
 /* Softmodem params */
@@ -524,6 +525,20 @@ void nr_mac_config_scc(gNB_MAC_INST *nrmac, NR_ServingCellConfigCommon_t *scc, c
         ra->preambles.preamble_list[i] = i;
     }
   }
+
+  //configure SRS for secondary cell
+  int curr_bwp = NRRIV2BW(scc->downlinkConfigCommon->initialDownlinkBWP->genericParameters.locationAndBandwidth,MAX_BWP_SIZE);
+
+  RC.nrmac[Mod_idP]->setup_srs_config[0] = calloc(1,sizeof(NR_SetupRelease_SRS_Config_t));
+  config_srs(scc,
+	     RC.nrmac[Mod_idP]->setup_srs_config[0],
+	     NULL,
+	     curr_bwp,
+	     0,   //lets assume ue_id = 0.
+	     0,   //res_id = 0 for initial BWP
+	     1,   //maxMIMO_Layers
+	     1);  //do_srsg
+  
   //NR_SCHED_UNLOCK(&nrmac->sched_lock);
 }
 

openair2/LAYER2/NR_MAC_gNB/gNB_scheduler.c

@@ -232,6 +232,9 @@ void gNB_dlsch_ulsch_scheduler(module_id_t module_idP, frame_t frame, sub_frame_
 
   nr_schedule_srs(module_idP, frame, slot);
 
+  if ((slot==0) && (get_softmodem_params()->phy_test == 0))
+    nr_schedule_srs_secondary(module_idP,frame,0/*UE_id*/);
+  
   // This schedule RA procedure if not in phy_test mode
   // Otherwise consider 5G already connected
   if (get_softmodem_params()->phy_test == 0) {

openair2/LAYER2/NR_MAC_gNB/gNB_scheduler_srs.c

@@ -589,3 +589,78 @@ void nr_schedule_srs(int module_id, frame_t frame, int slot)
     }
   }
 }
+
+/*******************************************************************
+*
+* NAME :         nr_schedule_srs_secondary
+*
+* PARAMETERS :   module id
+*                frame number for possible SRS reception
+*
+* DESCRIPTION :  It informs the PHY layer that has an SRS to receive.
+*                To be used at secondary gNB (where UE is not connected).
+*                Only for periodic scheduling yet.
+*
+*********************************************************************/
+void nr_schedule_srs_secondary(int module_id, frame_t frame, int UE_id) {
+
+  const int CC_id = 0;
+  // lets configure SRS on the initial BWP. This will only work for cell sizes of 60MHz or lower.
+  // for anything else this needs to be adapted to use the dedicated BWP.
+
+  
+  NR_ServingCellConfigCommon_t *scc = RC.nrmac[module_id]->common_channels[CC_id].ServingCellConfigCommon;
+  NR_SRS_Config_t *srs_config = RC.nrmac[module_id]->setup_srs_config[0]->choice.setup;
+
+  if(!scc) {
+    LOG_W(MAC,"no scc, returning\n");
+    return;
+  }
+
+    
+  for(int rs = 0; rs < srs_config->srs_ResourceSetToAddModList->list.count; rs++) {
+    
+    // Find periodic resource set
+    NR_SRS_ResourceSet_t *srs_resource_set = srs_config->srs_ResourceSetToAddModList->list.array[rs];
+    if (srs_resource_set->resourceType.present != NR_SRS_ResourceSet__resourceType_PR_periodic) {
+      continue;
+    }
+    
+      // Find the corresponding srs resource
+    NR_SRS_Resource_t *srs_resource = NULL;
+    for (int r1 = 0; r1 < srs_resource_set->srs_ResourceIdList->list.count; r1++) {
+      for (int r2 = 0; r2 < srs_config->srs_ResourceToAddModList->list.count; r2++) {
+	if ((*srs_resource_set->srs_ResourceIdList->list.array[r1] ==
+	     srs_config->srs_ResourceToAddModList->list.array[r2]->srs_ResourceId) &&
+	    (srs_config->srs_ResourceToAddModList->list.array[r2]->resourceType.present ==
+	     NR_SRS_Resource__resourceType_PR_periodic)) {
+	  srs_resource = srs_config->srs_ResourceToAddModList->list.array[r2];
+	  break;
+	}
+      }
+    }
+    
+    if (srs_resource == NULL) {
+        continue;
+    }
+    
+    NR_BWP_t ubwp = scc->uplinkConfigCommon->initialUplinkBWP->genericParameters;
+    
+    uint16_t period = srs_period[srs_resource->resourceType.choice.periodic->periodicityAndOffset_p.present];
+    uint16_t offset = get_nr_srs_offset(srs_resource->resourceType.choice.periodic->periodicityAndOffset_p);
+    
+    int n_slots_frame = nr_slots_per_frame[ubwp.subcarrierSpacing];
+
+    NR_UE_info_t dummy_ue_info;
+    dummy_ue_info.current_UL_BWP.BWPSize = NRRIV2BW(ubwp.locationAndBandwidth,MAX_BWP_SIZE);
+    dummy_ue_info.current_UL_BWP.BWPStart = NRRIV2PRBOFFSET(ubwp.locationAndBandwidth,MAX_BWP_SIZE);
+    dummy_ue_info.current_UL_BWP.scs = ubwp.subcarrierSpacing;
+    
+    // Check if UE will transmit the SRS in this frame
+    if ( ((frame - offset/n_slots_frame)*n_slots_frame)%period == 0) {
+      LOG_D(NR_MAC,"Scheduling SRS reception for %d.%d\n", frame, offset%n_slots_frame);
+      nr_fill_nfapi_srs(module_id, CC_id, &dummy_ue_info, offset%n_slots_frame, srs_resource);
+
+    }
+  }
+}

openair2/LAYER2/NR_MAC_gNB/mac_proto.h

@@ -170,6 +170,8 @@ int get_pucch_resourceid(NR_PUCCH_Config_t *pucch_Config, int O_uci, int pucch_r
 
 void nr_schedule_srs(int module_id, frame_t frame, int slot);
 
+void nr_schedule_srs_secondary(int module_id, frame_t frame, int UE_id);
+
 void nr_csirs_scheduling(int Mod_idP, frame_t frame, sub_frame_t slot, int n_slots_frame, nfapi_nr_dl_tti_request_t *DL_req);
 
 void nr_csi_meas_reporting(int Mod_idP,

openair2/LAYER2/NR_MAC_gNB/nr_mac_gNB.h

@@ -243,6 +243,7 @@ typedef struct {
   /// pre-configured ServingCellConfig that is default for every UE
   NR_ServingCellConfig_t *pre_ServingCellConfig;
   NR_ARFCN_ValueEUTRA_t ul_CarrierFreq;
+  
   long ul_Bandwidth;
   /// Outgoing MIB PDU for PHY
   uint8_t MIB_pdu[3];
@@ -869,6 +870,9 @@ typedef struct gNB_MAC_INST_s {
 
   pthread_mutex_t sched_lock;
 
+  //holds the SRS config for UEs of neighboring cells
+  //to be expanded to multiple users later
+  NR_SetupRelease_SRS_Config_t *setup_srs_config[1]; 
 } gNB_MAC_INST;
 
 #endif /*__LAYER2_NR_MAC_GNB_H__ */