Section: 6.1.3 Overall Architecture of IAB
Content: Figure 6.1.3-1: Overall architecture of IAB The NG-RAN supports IAB by the IAB-node wirelessly connecting to the gNB capable of serving the IAB-nodes, named IAB-donor. The IAB-donor consists of an IAB-donor-CU and one or more IAB-donor-DU(s). In case of separation of gNB-CU-CP and gNB-CU-UP, the IAB-donor may consist of an IAB-donor-CU-CP, multiple IAB-donor-CU-UPs and multiple IAB-donor-DUs. The IAB-node connects to an upstream IAB-node or an IAB-donor-DU via a subset of the UE functionalities of the NR Uu interface (named IAB-MT function of IAB-node). The IAB-node provides wireless backhaul to the downstream IAB-nodes and UEs via the network functionalities of the NR Uu interface (named IAB-DU function of IAB-node). The F1-C traffic between an IAB-node and IAB-donor-CU is backhauled via the IAB-donor-DU and the optional intermediate hop IAB-node(s). The F1-U traffic between an IAB-node and IAB-donor-CU is backhauled via the IAB-donor-DU and the optional intermediate hop IAB-node(s). All functions specified for a gNB-DU are equally applicable for an IAB-DU and IAB-donor-DU, unless otherwise stated, and all functions specified for a gNB-CU are equally applicable for an IAB-donor-CU, unless otherwise stated. All functions specified for the UE context are equally applicable for managing the context of IAB-MT, unless otherwise stated.