5G技术培训EN-DC-UE(1)课件.pdfVIP

5G secondary node addition UE.pdf LTE-5GNR UE LTE eNodeB 5G-NR gNodeB UE MN-eNB SN-gNB 4G-LTE attach procedure 1:Random Access Preamble The terminal initiates a new session with the randomly selected preamble. 2:Random Access Response The eNodeB responds to the preamble with the Random Access Response message on the DL-SCH. 3:RRC Connection Request The UE uses a UL-SCH allocation to send the RRC Connection Request message. 4:RRC Connection Setup (SRB1) eNodeB responds with an RRC Connection Setup message on the DL-SCH. 5:RRC Connection Setup Complete The UE signals the completion of the RRC connection. The message carries the [NAS Attach Request (DCNR)] NAS Attach Request. The DCNR bit in the UE Network Capability IE is set. This [PDN Connectivity Request] signals to the 4G Core Network that the UE supports dual connectivity with 4G-LTE and 5G-NR. 6:Downlink NAS Transport MME initiates the authentication procedure [Authentication Request] 7:Uplink NAS Transport Authentication is successfully completed. [Authentication Response] 8:Downlink NAS Transport MME initiates NAS level security procedure. [Security Mode Command] 9:Uplink NAS Transport NAS level security procedure is completed. From this point, all communication [Security Mode Complete]