Compute frame/slot at gNB to receive the SRS

cmake_targets/CMakeLists.txt

@@ -2119,6 +2119,7 @@ set (MAC_NR_SRC
   ${NR_GNB_MAC_DIR}/gNB_scheduler_primitives.c
   ${NR_GNB_MAC_DIR}/gNB_scheduler_phytest.c
   ${NR_GNB_MAC_DIR}/gNB_scheduler_uci.c
+  ${NR_GNB_MAC_DIR}/gNB_scheduler_srs.c
   ${NR_GNB_MAC_DIR}/gNB_scheduler_RA.c
  )
 

openair2/LAYER2/NR_MAC_gNB/gNB_scheduler.c

@@ -397,6 +397,8 @@ void gNB_dlsch_ulsch_scheduler(module_id_t module_idP,
 
   nr_schedule_pucch(module_idP, frame, slot);
 
+  nr_schedule_srs(module_idP, frame, slot);
+
   stop_meas(&RC.nrmac[module_idP]->eNB_scheduler);
   
   VCD_SIGNAL_DUMPER_DUMP_FUNCTION_BY_NAME(VCD_SIGNAL_DUMPER_FUNCTIONS_gNB_DLSCH_ULSCH_SCHEDULER,VCD_FUNCTION_OUT);

openair2/LAYER2/NR_MAC_gNB/gNB_scheduler_srs.c

@@ -0,0 +1,119 @@
+/*
+ * Licensed to the OpenAirInterface (OAI) Software Alliance under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The OpenAirInterface Software Alliance licenses this file to You under
+ * the OAI Public License, Version 1.1  (the "License"); you may not use this file
+ * except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.openairinterface.org/?page_id=698
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *-------------------------------------------------------------------------------
+ * For more information about the OpenAirInterface (OAI) Software Alliance:
+ *      contact@openairinterface.org
+ */
+
+/*! \file gNB_scheduler_srs.c
+ * \brief MAC procedures related to SRS
+ * \date 2021
+ * \version 1.0
+ */
+
+#include <softmodem-common.h>
+#include "LAYER2/MAC/mac.h"
+#include "NR_MAC_gNB/nr_mac_gNB.h"
+#include "NR_MAC_COMMON/nr_mac_extern.h"
+#include "NR_MAC_gNB/mac_proto.h"
+#include "common/ran_context.h"
+#include "nfapi/oai_integration/vendor_ext.h"
+
+extern RAN_CONTEXT_t RC;
+
+/*******************************************************************
+*
+* NAME :         nr_schedule_srs
+*
+* PARAMETERS :   module id
+*                frame number for possible SRS reception
+*                slot number for possible SRS reception
+*
+* DESCRIPTION :  It informs the PHY layer that has an SRS to receive.
+*                Only for periodic scheduling yet.
+*
+*********************************************************************/
+void nr_schedule_srs(int module_id, frame_t frame, sub_frame_t slot) {
+
+  gNB_MAC_INST *nrmac = RC.nrmac[module_id];
+  NR_UE_info_t *UE_info = &nrmac->UE_info;
+  const NR_list_t *UE_list = &UE_info->list;
+
+  for (int UE_id = UE_list->head; UE_id >= 0; UE_id = UE_list->next[UE_id]) {
+
+    const int CC_id = 0;
+    NR_ServingCellConfigCommon_t *scc = RC.nrmac[module_id]->common_channels[CC_id].ServingCellConfigCommon;
+    NR_CellGroupConfig_t *cg = UE_info->CellGroup[UE_id];
+    NR_UE_sched_ctrl_t *sched_ctrl = &UE_info->UE_sched_ctrl[UE_id];
+
+    if(!UE_info->active[UE_id]) {
+      continue;
+    }
+
+    NR_SRS_Config_t *srs_config = NULL;
+    if (cg &&
+        cg->spCellConfig &&
+        cg->spCellConfig->spCellConfigDedicated &&
+        cg->spCellConfig->spCellConfigDedicated->uplinkConfig &&
+        cg->spCellConfig->spCellConfigDedicated->uplinkConfig->initialUplinkBWP) {
+      srs_config = cg->spCellConfig->spCellConfigDedicated->uplinkConfig->initialUplinkBWP->srs_Config->choice.setup;
+    } else {
+      continue;
+    }
+
+    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 = sched_ctrl->active_ubwp ?
+                        sched_ctrl->active_ubwp->bwp_Common->genericParameters :
+                        scc->uplinkConfigCommon->initialUplinkBWP->genericParameters;
+
+      uint16_t period = srs_period[srs_resource->resourceType.choice.periodic->periodicityAndOffset_p.present];
+      uint16_t offset = srs_resource->resourceType.choice.periodic->periodicityAndOffset_p.choice.sl40;
+
+      int n_slots_frame = nr_slots_per_frame[ubwp.subcarrierSpacing];
+
+      // Check if UE transmitted the SRS here
+      if ((frame * n_slots_frame + slot - offset) % period == 0) {
+        LOG_W(NR_MAC,"(%d.%d) SRS is received here, but the procedures are not implemented yet!\n", frame, slot);
+      }
+    }
+  }
+}

openair2/LAYER2/NR_MAC_gNB/mac_proto.h

@@ -190,6 +190,8 @@ void nr_schedule_pucch(int Mod_idP,
                        frame_t frameP,
                        sub_frame_t slotP);
 
+void nr_schedule_srs(int module_id, frame_t frame, sub_frame_t slot);
+
 void nr_csirs_scheduling(int Mod_idP,
                          frame_t frame,
                          sub_frame_t slot,