5G-Advanced network architecture

Let's look at the 5G system more closely in order to better locate the enhancements and features made in 5G-Advanced. 5G-Advanced follows the same system architecture as 5G, which is referred to as a 5G system here, also called a 5G standalone system. There are three parts of the 5G system. From left to right, we have user equipment or UE, a device that a user uses with a radio access technology and can access to a 5G network. A UE can have different forms such as a smartphone, an augmented or extended reality device, a wearable device, IoT device, a drone, a satellite user terminal, and many more. Besides UEs, there is a 5G radio access network called NG-RAN consisting of 5G base stations called G Node B, or simply gNB. Each gNB covers a geographical area called a cell where UEs are covered. This is why a mobile network such as 5G is also called a cellular network. In 5G, a gNB may be further split into two decoupled entities called a gNB Distributed Unit, gNB-DU, and gNB Central Unit, gNB-CU. Both entities interact with each other through the logical F1 interface. gNB frequently contact the UEs and can interact with each other through the Xn interfaces. All gNBs connected to the 5G core network called 5GC. With a 5GC, there are multiple network functions providing different services based on the service-based architecture. They can interact with each other through the service exposed, and some of them have direct connections to the gNBs. The lines between the functions show they can interact with each other with their service interfaces and exchange messages. Some standard network functions are shown here, such as the Access and Mobility Management Function, AMF, User Plane Function, UPF, Session Management Function, SMF, and so on. The security-related network functions are Network Exposure Function, AEF, Authentication Server Function, AUSF, and Security Anchor Functionality, SEAF, where SEAF is part of AMF. In order to allow UE to access to the data network or internet, external to the 5G system, the UPF handles the data traffic between UE and the data network, where different application servers and the cloud computing services are located. All these entities need some connections, which are defined as reference points or interfaces. Among all interfaces, a few examples are shown here, such as Xn, N2, N3, and N6. Different data traverse through these logical interfaces belonging to the conceptual user plane and the control plane. User plane handles the user data such as the application messages. Control plane handles the radio resource control, resource management, and other signaling traffic. The interfaces used for the user plane and the control plane are marked in different lines. The Xn interface between the gNBs handles both user and control plane data. N2 is for control plane and N3 and N6 are for the user plane. In a simplified view, the collective interface between NG-RAN and 5G core can be referred to as NG. Overall, this 5G system architecture shows a well-defined and flexible control loop. Each part can be enhanced with new features and functionalities. The enhancements made for the 5G-Advanced are based on these 3GPP working groups under three Technical Specification Groups, which are radio access network, core network and terminals, and the service and assistant aspects. A rough mapping between the groups and the 5G system entities can be established from the diagram here, although they are aspects that cannot be exactly mapped to the entities. If there is a new service to be added, RAN and the core network can be enhanced to support it. For example, for AR or XR media service and UAV applications, new network functions can be added to support them, and the new interfaces or reference points can be added to handle the specific messages and the signaling at RAN and the core networks to support new types of UE devices or networks requiring new UE device functionalities such as personal IoT network and XR device. The UE part needs to be enhanced. The air interface and radio access network enhancement topics are focused on mostly UE and NG-RAN. AI or machine learning-related support such as AI, ML, model management, and the data collection occurs at the NG-RAN and the UE as well as 5GC. The 5G data analytics services such as network data analytics function and management data analytics applies to the NG-RAN and the 5GC. The UAV's satellite access or non-terrestrial network access are related to the UE and NG-RAN for the essential radio interface support, and also 5GC for management and application support. The security aspects are more overarching, which are related to the fundamental 5G services and also to the applications and the use cases to be supported, as each of them may have unique security challenges to deal with, although some of them can be built on top of the existing 5G security. I hope this provides a clear view of what we are talking about regarding the 5G-Advanced enhancements arising from the 5G system. There are many enhancements that are cross-cutting and overlapping, but we try to categorize them into easy-to-understand ways in the following videos.