Section: 4.8.2.4 Connection Resume in CM-IDLE with Suspend and MO EDT procedure
Content: The Connection Resume with Early Data Transmission procedure is used by the UE to optimise sending user data in a single uplink packet and single uplink followed by single downlink packet cases for a UE in CM-IDLE with Suspend. Figure 4.8.2.4-1: Connection Resume in RRC_IDLE with Suspend with EDT 1. UE to NG-eNB: RRC message (Resume ID, AS RAI) with UL EDT. The UE initiates the transition from RRC_IDLE with Suspend state to RRC_CONNECTED state, see TS 36.300[ Evolved Universal Terrestrial Radio Access (E-UTRA) and Evolved Universal Terrestrial Radio Access Network (E-UTRAN); Overall description; Stage 2 ]  [46]. The UE may include AS Release Assistance information indicating: - No further Uplink and Downlink Data transmission, or - Only a single Downlink Data transmission subsequent to the Uplink transmission. 2. The NG-eNB deciphers the EDT UL data received from the UE and forwards it to the UPF using the N3 UL TEID in the AS context. 3. The NG-eNB sends N2 Resume Request to AMF including Resume cause and N2 SM. If the UE included AS Release Assistance information indicating No further Uplink and Downlink Data transmission in step 1, NG-eNB may request for immediate transition to RRC_IDLE with Suspend. If the NG-eNB requests for immediate transition to RRC_IDLE with Suspend, the NG-eNB should include Paging Assistance Data for CE capable UE in the N2 Resume Request message. If the NG-eNB supports WUS and requests for immediate transition to RRC_IDLE with Suspend, the NG-eNB should include Information on Recommended Cells and RAN Nodes for Paging in the N2 Resume Request message. The AMF stores this information in the UE context for subsequent Paging procedure. 4. [Conditional] The AMF interacts with SMF to establish the N3 tunnel, except for the case: - The AMF receives a request for immediate transition to RRC_IDLE with Suspend in step 3; and - the AMF is not aware of any downlink data or signalling pending. 5. The AMF sends an N2 Resume Response to NG-eNB. If the AMF received a request for immediate transition to RRC_IDLE with Suspend in step 3 and there is no downlink data or signalling pending, the AMF includes a Suspend indication, keeps the UE in CM-IDLE with Suspend and restarts the Periodic Registration Timer unless the Strictly Periodic Registration Timer Indication has been provided to the UE during the previous registration procedure. Otherwise the AMF sends an N2 Resume Response to NG-eNB after the N3 Connectivity has been established and moves the UE to CM-CONNECTED. If the AMF knows of mobile terminating data or signalling pending, the AMF may include the Extended Connected Time value to the RAN 6. [Conditional] RRC procedure: 6a. If the AMF included the Suspend indication, the NG-eNB releases the RRC Connection with Suspend. The procedure is complete and following steps are skipped. 6b. If the AMF did not include the Suspend indication and: - The UE did not include AS Release Assistance Indication; or - The AMF included the Extended Connected Time value. the NG-eNB sends an RRC Resume message to the UE and the UE moves to CM-CONNECTED and RRC_CONNECTED. The procedure is complete and the following steps are skipped. 6c. Otherwise, if the AMF did not include Extended Connected Time value and the UE included AS Release Assistance information with only a single Downlink Data transmission subsequent to the Uplink transmission, the NG-eNB waits for the DL data to arrive and proceeds to steps 7-10. 7-9. The NG-eNB releases the N3 connectivity by sending an N2 Suspend Request to AMF including Suspend cause and N2 SM. Steps 2-4 of Connection Suspend procedure in clause 4.8.1.2 is executed. 10. [Conditional] NG-eNB to UE: RRC message (with DL data). The NG-eNB ciphers received DL data. The NG-eNB releases the RRC Connection with Suspend including the DL EDT data.