4.1 Overall Architecture

38.3003GPPNRNR and NG-RAN Overall descriptionRelease 17Stage 2TS

An NG-RAN node is either:

– a gNB, providing NR user plane and control plane protocol terminations towards the UE; or

– an ng-eNB, providing E-UTRA user plane and control plane protocol terminations towards the UE.

The gNBs and ng-eNBs are interconnected with each other by means of the Xn interface. The gNBs and ng-eNBs are also connected by means of the NG interfaces to the 5GC, more specifically to the AMF (Access and Mobility Management Function) by means of the NG-C interface and to the UPF (User Plane Function) by means of the NG-U interface (see TS 23.501 [3]).

NOTE: The architecture and the F1 interface for a functional split are defined in TS 38.401 [4].

The NG-RAN architecture is illustrated in Figure 4.1-1 below.

Figure 4.1-1: Overall Architecture