Section: 8.18.3 RA-SDT or non-SDT with CG-SDT configuration
Content: The procedure for the case where the UE has CG-SDT resource configurations but decides to perform RACH based small data transmission in RRC Inactive or to perform RACH procedure to transit to RRC Connected (see TS 38.321[ NR; Medium Access Control (MAC) protocol specification ]  [30] clause 5.27) is shown in Figure 8.18.3-1. Figure 8.18.3-1: RA-SDT or non-SDT with CG-SDT configuration. 1. The UE in RRC Inactive sends RRCResumeRequest message. If the UE decides to perform RACH based SDT procedure, it also sends UL SDT data and/or UL SDT signalling. 2. The gNB-DU buffers the UL SDT data and/or UL SDT signalling. 3. The gNB-DU sends the INITIAL UL RRC MESSAGE TRANSFER message to the gNB-CU-CP, including a new gNB-DU UE F1AP ID, and in case of RACH based SDT access, the gNB-DU provides an indication of SDT access and may also the SDT assistance information. 4. If UE context is successfully retrieved as specified in TS 38.300[ NR; NR and NG-RAN Overall description; Stage-2 ]  [2], the gNB-CU-CP sends the UE CONTEXT SETUP REQUEST message with the stored (or retrieved from the last serving gNB) F1 UL TEIDs and the new gNB-DU UE F1AP ID received in step 3. In case that the gNB-DU is the one that sent the RRCRelease message with CG-SDT resource configurations to the UE, the gNB-CU-CP also includes the old gNB-DU UE F1AP ID and the old gNB-CU F1AP UE ID within the Old CG-SDT Session Info IE of the UE CONTEXT SETUP REQUEST message. In case that the gNB-CU-CP is the one that generated the RRCRelease message with CG-SDT resource configurations but the gNB-DU is not the old gNB-DU that sent the RRCRelease message to the UE, the gNB-CU-CP initiates the UE Context Release procedure by sending the UE CONTEXT RELEASE COMMAND message to the old gNB-DU. In case that the UE accesses a gNB other than the last serving gNB, upon receiving the RETRIEVE UE CONTEXT REQUEST message from the receiving gNB-CU-CP, the last serving gNB-CU-CP initiates the UE Context Release procedure by sending the UE CONTEXT RELEASE COMMAND message to the last serving gNB-DU. 5. The gNB-DU sends the UE CONTEXT SETUP RESPONSE message with the new gNB-DU UE F1AP ID. In case the old gNB-DU UE F1AP ID is received within the Old CG-SDT Session Info IE in step 4, the gNB-DU retrieves the stored CG-SDT resource configurations and UE context based on the Old CG-SDT Session Info IE, if any, and associates them with the new gNB-DU F1AP UE ID.