8.16 Overall procedures for CPAC

38.4013GPPArchitecture descriptionNG-RANRelease 17TS

The following clauses describe the overall procedures for CPAC involving E1 and F1.

8.16.1 MN initiated Conditional PSCell Addition

The procedure for MN initiated Conditional PSCell Addition (CPA) is shown in Figure 8.16-1.

Figure 8.16.1-1 Conditional Secondary Node Addition procedure

1-12. The steps 1-12 are as defined in TS 37.340 [12].

a1-a5. The steps a1-a5 are as defined in clause 8.9.2 and with conditional indications.

a6. After Random Access procedure successfully performed at the candidate gNB-DU which becomes the target SN gNB-DU, the target gNB-DU sends a Downlink Data Delivery Status frame to inform the target gNB-CU-UP. The target gNB-DU also sends an ACCESS SUCCESS message to inform the target gNB-CU-CP of which cell the UE has successfully accessed.

8.16.2 MN initiated conditional SN Change

The procedure for MN initiated conditional SN Change refer to TS 37.340[12]. In case of split gNB architecture, the procedures between gNB-CU and gNB-DU and the procedures between gNB-CU-CP and gNB-CU-UP refer to 8.16.1.

8.16.3 SN initiated conditional inter-SN Change

The procedure for SN initiated conditional SN Change refer to TS 37.340[12]. In case of split gNB architecture, the procedures between gNB-CU and gNB-DU and the procedures between gNB-CU-CP and gNB-CU-UP refer to 8.16.1.