Improvements on BWP switch procedures and harmonize it with RRC processing timer

openair2/LAYER2/NR_MAC_gNB/gNB_scheduler_primitives.c

@@ -2365,9 +2365,8 @@ int add_new_nr_ue(module_id_t mod_idP, rnti_t rntiP, NR_CellGroupConfig_t *CellG
                                                   scc,
                                                   genericParameters,
                                                   NULL);
-    sched_ctrl->bwp_switch_info.current_bwp = bwp_id;
-    sched_ctrl->bwp_switch_info.next_bwp = -1;
-    sched_ctrl->bwp_switch_info.bwp_switch_state = BWP_SWITCH_INACTIVE;
+    sched_ctrl->next_dl_bwp_id = -1;
+    sched_ctrl->next_ul_bwp_id = -1;
     const struct NR_UplinkConfig__uplinkBWP_ToAddModList *ubwpList = servingCellConfig ? servingCellConfig->uplinkConfig->uplinkBWP_ToAddModList : NULL;
     if (ubwpList) AssertFatal(ubwpList->list.count <= NR_MAX_NUM_BWP,
 			      "uplinkBWP_ToAddModList has %d BWP!\n",
@@ -2900,52 +2899,6 @@ void nr_mac_update_timers(module_id_t module_id,
   }
 }
 
-void nr_bwp_switch(module_id_t module_id,
-                   frame_t frame,
-                   sub_frame_t slot,
-                   int UE_id,
-                   int bwp_id) {
-
-  NR_UE_info_t *UE_info = &RC.nrmac[module_id]->UE_info;
-  NR_UE_sched_ctrl_t *sched_ctrl = &UE_info->UE_sched_ctrl[UE_id];
-
-  switch(sched_ctrl->bwp_switch_info.bwp_switch_state) {
-
-    case BWP_SWITCH_TO_START:
-      LOG_W(NR_MAC,"(%d.%d) [UE_id %d] Schedule BWP switch from bwp_id %ld to %d\n",
-            frame, slot, UE_id, UE_info->UE_sched_ctrl[UE_id].active_bwp->bwp_Id, bwp_id);
-      sched_ctrl->bwp_switch_info.bwp_switch_state = BWP_SWITCH_RUNNING;
-      sched_ctrl->bwp_switch_info.bwp_switch_slot = slot;
-      nr_mac_rrc_bwp_switch_req(module_id, frame, slot, UE_info->rnti[UE_id], bwp_id);
-      break;
-
-    case BWP_SWITCH_RUNNING:
-      // The BWP switching takes at least 10+6 ms (3GPP TS 38.331 Section 12)
-      // gNB needs time to schedule and send RRCReconfiguration message
-      // Therefore, we wait for the same slot in next frame (10 ms) before update bwp_id in the gNB
-      if (sched_ctrl->bwp_switch_info.bwp_switch_slot == slot) {
-        const NR_ServingCellConfig_t *servingCellConfig = UE_info->CellGroup[UE_id] ? UE_info->CellGroup[UE_id]->spCellConfig->spCellConfigDedicated : NULL;
-        const struct NR_ServingCellConfig__downlinkBWP_ToAddModList *bwpList = servingCellConfig ? servingCellConfig->downlinkBWP_ToAddModList : NULL;
-        const int bwp_id = servingCellConfig && servingCellConfig->firstActiveDownlinkBWP_Id ?
-                           *servingCellConfig->firstActiveDownlinkBWP_Id : 0;
-        sched_ctrl->active_bwp = bwpList && bwp_id > 0 ? bwpList->list.array[bwp_id - 1] : NULL;
-        const struct NR_UplinkConfig__uplinkBWP_ToAddModList *ubwpList = servingCellConfig ? servingCellConfig->uplinkConfig->uplinkBWP_ToAddModList : NULL;
-        const int ubwp_id = servingCellConfig && servingCellConfig->uplinkConfig && servingCellConfig->uplinkConfig->firstActiveUplinkBWP_Id ?
-                            *servingCellConfig->uplinkConfig->firstActiveUplinkBWP_Id : 0;
-        sched_ctrl->active_ubwp = ubwpList && ubwp_id > 0 ? ubwpList->list.array[ubwp_id - 1] : NULL;
-        sched_ctrl->bwp_switch_info.bwp_switch_state = BWP_SWITCH_INACTIVE;
-      }
-      break;
-
-    case BWP_SWITCH_INACTIVE:
-      break;
-
-    default:
-      AssertFatal(1==0,"Invalid bwp switch state\n");
-      break;
-  }
-}
-
 void schedule_nr_bwp_switch(module_id_t module_id,
                             frame_t frame,
                             sub_frame_t slot) {
@@ -2954,16 +2907,21 @@ void schedule_nr_bwp_switch(module_id_t module_id,
   const NR_list_t *UE_list = &UE_info->list;
 
   // TODO: Implementation of a algorithm to perform:
-  //  - the BWP switch trigger: sched_ctrl->bwp_switch_info.bwp_switch_state = BWP_SWITCH_TO_START
-  //  - the BWP selection:      sched_ctrl->bwp_switch_info.next_bwp = bwp_id
+  //  - DL BWP selection:     sched_ctrl->next_dl_bwp_id = dl_bwp_id
+  //  - UL BWP selection:     sched_ctrl->next_ul_bwp_id = ul_bwp_id
 
   for (int UE_id = UE_list->head; UE_id >= 0; UE_id = UE_list->next[UE_id]) {
     NR_UE_sched_ctrl_t *sched_ctrl = &UE_info->UE_sched_ctrl[UE_id];
-    if(sched_ctrl->bwp_switch_info.bwp_switch_state > BWP_SWITCH_INACTIVE) {
-      nr_bwp_switch(module_id, frame, slot, UE_id, sched_ctrl->bwp_switch_info.next_bwp);
+    if (sched_ctrl->rrc_processing_timer == 0 &&
+        UE_info->Msg4_ACKed[UE_id] == true &&
+        ((sched_ctrl->next_dl_bwp_id >= 0 && sched_ctrl->active_bwp && sched_ctrl->active_bwp->bwp_Id != sched_ctrl->next_dl_bwp_id) ||
+        (sched_ctrl->next_ul_bwp_id >= 0 && sched_ctrl->active_ubwp && sched_ctrl->active_ubwp->bwp_Id != sched_ctrl->next_ul_bwp_id))) {
+
+      LOG_W(NR_MAC,"(%d.%d) [UE_id %d] Schedule BWP switch from dl_bwp_id %ld to %ld and from ul_bwp_id %ld to %ld\n",
+            frame, slot, UE_id, sched_ctrl->active_bwp->bwp_Id, sched_ctrl->next_dl_bwp_id, sched_ctrl->active_ubwp->bwp_Id, sched_ctrl->next_ul_bwp_id);
+      nr_mac_rrc_bwp_switch_req(module_id, frame, slot, UE_info->rnti[UE_id], sched_ctrl->next_dl_bwp_id, sched_ctrl->next_ul_bwp_id);
     }
   }
-
 }
 
 /*void fill_nfapi_coresets_and_searchspaces(NR_CellGroupConfig_t *cg,

openair2/LAYER2/NR_MAC_gNB/nr_mac_gNB.h

@@ -558,19 +558,6 @@ typedef struct NR_UE_ul_harq {
   NR_sched_pusch_t sched_pusch;
 } NR_UE_ul_harq_t;
 
-typedef enum {
-  BWP_SWITCH_INACTIVE = 0,
-  BWP_SWITCH_TO_START,
-  BWP_SWITCH_RUNNING
-} NR_BWP_switch_states_t;
-
-typedef struct NR_BWP_switch_info {
-  NR_BWP_Id_t current_bwp;
-  NR_BWP_Id_t next_bwp;
-  sub_frame_t bwp_switch_slot;
-  NR_BWP_switch_states_t bwp_switch_state;
-} NR_BWP_switch_info_t;
-
 /*! \brief scheduling control information set through an API */
 #define MAX_CSI_REPORTS 48
 typedef struct {
@@ -579,8 +566,10 @@ typedef struct {
   /// the currently active BWP in UL
   NR_BWP_Uplink_t *active_ubwp;
 
-  /// the state of bwp switch procedure
-  NR_BWP_switch_info_t bwp_switch_info;
+  /// the next active BWP ID in DL
+  NR_BWP_Id_t next_dl_bwp_id;
+  /// the next active BWP ID in UL
+  NR_BWP_Id_t next_ul_bwp_id;
 
   /// CCE index and aggregation, should be coherent with cce_list
   NR_SearchSpace_t *search_space;

openair2/RRC/NR/L2_nr_interface.c

@@ -297,13 +297,14 @@ int8_t nr_mac_rrc_bwp_switch_req(const module_id_t     module_idP,
                                  const frame_t         frameP,
                                  const sub_frame_t     sub_frameP,
                                  const rnti_t          rntiP,
-                                 const int             bwp_id) {
+                                 const int             dl_bwp_id,
+                                 const int             ul_bwp_id) {
 
   struct rrc_gNB_ue_context_s *ue_context_p = rrc_gNB_get_ue_context(RC.nrrrc[module_idP], rntiP);
 
   protocol_ctxt_t ctxt;
   PROTOCOL_CTXT_SET_BY_MODULE_ID(&ctxt, module_idP, GNB_FLAG_YES, rntiP, frameP, sub_frameP, 0);
-  nr_rrc_reconfiguration_req(ue_context_p, &ctxt, bwp_id);
+  nr_rrc_reconfiguration_req(ue_context_p, &ctxt, dl_bwp_id, ul_bwp_id);
 
   return 0;
 }

openair2/RRC/NR/nr_rrc_proto.h

@@ -171,7 +171,8 @@ int8_t nr_mac_rrc_bwp_switch_req(const module_id_t     module_idP,
                                  const frame_t         frameP,
                                  const sub_frame_t     sub_frameP,
                                  const rnti_t          rntiP,
-                                 const int             bwp_id);
+                                 const int             dl_bwp_id,
+                                 const int             ul_bwp_id);
 
 int8_t nr_mac_rrc_data_ind(
     const module_id_t     module_idP,
@@ -188,7 +189,8 @@ int8_t nr_mac_rrc_data_ind(
 
 int nr_rrc_reconfiguration_req(rrc_gNB_ue_context_t         *const ue_context_pP,
                                protocol_ctxt_t              *const ctxt_pP,
-                               const int                    bwp_id);
+                               const int                    dl_bwp_id,
+                               const int                    ul_bwp_id);
 
 int nr_rrc_gNB_decode_ccch(protocol_ctxt_t    *const ctxt_pP,
                            const uint8_t      *buffer,

openair2/RRC/NR/rrc_gNB.c

@@ -1942,16 +1942,21 @@ rrc_gNB_process_RRCConnectionReestablishmentComplete(
 
 int nr_rrc_reconfiguration_req(rrc_gNB_ue_context_t         *const ue_context_pP,
                                protocol_ctxt_t              *const ctxt_pP,
-                               const int                    bwp_id) {
+                               const int                    dl_bwp_id,
+                               const int                    ul_bwp_id) {
 
   uint8_t buffer[RRC_BUF_SIZE];
   memset(buffer, 0, sizeof(buffer));
   uint8_t xid = rrc_gNB_get_next_transaction_identifier(ctxt_pP->module_id);
 
   NR_CellGroupConfig_t *masterCellGroup = ue_context_pP->ue_context.masterCellGroup;
-  *masterCellGroup->spCellConfig->spCellConfigDedicated->firstActiveDownlinkBWP_Id = bwp_id;
-  *masterCellGroup->spCellConfig->spCellConfigDedicated->defaultDownlinkBWP_Id = bwp_id;
-  *masterCellGroup->spCellConfig->spCellConfigDedicated->uplinkConfig->firstActiveUplinkBWP_Id = bwp_id;
+  if (dl_bwp_id >= 0) {
+    *masterCellGroup->spCellConfig->spCellConfigDedicated->firstActiveDownlinkBWP_Id = dl_bwp_id;
+    *masterCellGroup->spCellConfig->spCellConfigDedicated->defaultDownlinkBWP_Id = dl_bwp_id;
+  }
+  if (ul_bwp_id >= 0) {
+    *masterCellGroup->spCellConfig->spCellConfigDedicated->uplinkConfig->firstActiveUplinkBWP_Id = ul_bwp_id;
+  }
 
   uint16_t  size = do_RRCReconfiguration(ctxt_pP,
                                          buffer,