Section: 4.8.2.2a Network Triggered Connection Resume in RRC_INACTIVE procedure
Content: The Network Triggered Connection Resume in RRC_INACTIVE procedure is used when the NG-RAN needs to send data (e.g. the N1 NAS PDU and/or downlink user plane PDU) to a UE in the RRC_INACTIVE state. During the procedure, the NG-RAN sends a RAN Paging to the UE in order to trigger the Connection Resume in RRC_INACTIVE procedure in clause 4.8.2.2. Figure 4.8.2.2a-1: Network Triggered Connection Resume for UE in RRC_INACTIVE 1. The NG-RAN receives downlink data (e.g. the N1 NAS PDU and/or the user plane PDU) for a UE in RRC_INACTIVE State, the NG-RAN buffers the downlink data and triggers RAN Paging message. If the NG RAN supports the Paging Cause Indication for Voice Service feature and if the UE context in NG-RAN indicates that the UE supports the Paging Cause Indication for Voice Service feature, the NG RAN shall provide the Voice Service Indication in the RAN Paging message for the UE when it detects that the downlink data which triggers the RAN Paging message is related to voice service, as specified in clause 5.38.3 of TS 23.501[ System architecture for the 5G System (5GS) ]  [2]. 2. The NG-RAN sends the RAN Paging message to the UE. 3. If the UE is in RRC_INACTIVE State, based on the RAN paging and the UE decides to accept the paging, the UE initiates the UE Triggered Connection Resume in RRC_INACTIVE procedure (see clause 4.8.2.2).