Section: 8.9.6.2 RRC Inactive to other states
Content: The procedure for changing the UE state from RRC-inactive to RRC-connected is shown in Figure 8.9.6.2-1. Figure 8.9.6.2-1: RRC Inactive to RRC Connected state transition. 0. The gNB-CU-UP receives DL data on NG-U interface. 1. The gNB-CU-UP sends DL DATA NOTIFICATION message to the gNB-CU-CP. 2. The gNB-CU-CP sends PAGING message to the gNB-DU. 3. The gNB-DU sends the Paging message to the UE. NOTE: steps 0-3 are needed only in case of DL data. 4. The UE sends RRCResumeRequest message either upon RAN paging or UL data arrival. 5. The gNB-DU sends the INITIAL UL RRC MESSAGE TRANSFER message to the gNB-CU-CP. 6. The gNB-CU-CP sends UE CONTEXT SETUP REQUEST message including the stored F1 UL TEIDs to create the UE context in the gNB-DU. 7. The gNB-DU responds with the UE CONTEXT SETUP RESPONSE message including the F1 DL TEIDs allocated for the DRBs. 8. The gNB-CU-CP and the UE perform the RRC-Resume procedure via the gNB-DU. 9. The gNB-CU-CP sends BEARER CONTEXT MODIFICATION REQUEST message with a RRC Resume indication, which indicates that the UE is resuming from RRC-inactive state. The gNB-CU-CP also includes the F1 DL TEIDs received from the gNB-DU in step 7. 10. The gNB-CU-UP responds with theBEARER CONTEXT MODIFICATION RESPONSE message. NOTE steps 8 and 9 can be performed in parallel.