5G Network Abbreviation and Terminologies

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• New RAN: A Radio Access Network which can support either NR/E-UTRA or both and they have capabilities to interface with Next Generation Core network (NG-CN). NG-C/U is the control/user plane interface towards the core network. 

• gNB:  New Radio (NR) base stations having a capability to interface with 5G core named as NG-CN over NG-C/U (NG2/NG3) interface as well as 4G core known as the EPC over S1-C/U interface. 

• 5GC: The new 5G core is based on a Service-based Architecture that implements the IT network principles and cloud-native design approaches. In 5GC, there are network functions where each NF is formed by a combination of small pieces of software code called microservices. Each NF offers one or more services to other NFs via API (Application Programming Interfaces). 5GC allows it automatically. upgrades and the addition of new functionalities with no impact on already running services.

• eLTE eNB: The eLTE eNB is the evolution of eNB that supports connectivity to the Evolved Packet Core and NGC (Next Generation core ). 

• Non-Standalone NR: The Non-Standalone mode of 5G NR refers to an option of 5G NR deployment that depends on the control plane of an existing 4G LTE network for control functions and 5G NR is exclusively focused on the user plane. In this case, the new radio base stations are connected via a 4G network. 4G EPC (Evolved Packet Core) is required for the control plane communications and mobility management procedures. The benefit of 5G NSA is a short time to market, faster and more efficient mobile broadband. NSA deployment options are option 3: NSA LTE and NR under EPC, option 4: NSA NR and LTE under 5GC, and option 7: NSA LTE and NR under 5GC.  

• Standalone NR: The new radio and the 5G Core are independent of the LTE technology with this. Voice services will also be supported in this and there is a handover between 5G and other generations for both voice and data services. Benefits of this type of core include enhanced end-user experience, simplified operations, and service agility, improved network capabilities, and future-proof network architecture. SA deployment options are option 1: SA LTE under EPC, option 2: SA NR under 5GC, and option 5: SA LTE under 5GC. The enhanced Mobile broadband service may be accommodated on any 5G Architecture options with similar total capacity and end-user experience. The theoretical data throughput will be higher when using NSA approaches with deployment options 3,4 and 7. Mid and high-band NR would not offer significant coverage when used to support SA option 2. Option 3 enables a faster time to market since the core network can be upgraded later. Due to 5G NR, users can experience better throughput. However, with this increased traffic, EPC may become a bottleneck. From this NSA option 3, the operator can migrate to NSA option 7 or SA option 5. With options like options 7 and 5, 5G core can enable all 5G services. 

• Non-Standalone E-UTRA: It is a 5G network deployment configuration where the eLTE eNB requires a gNB as an anchor for control plane connectivity to NG-CN. 

• Standalone E-UTRA: It is a typical 4G network deployment where a 4G LTE eNB connects to the Evolved Packet Core. 

• Xn interface: The Xn interface is a logical interface that interconnects the new RAN nodes i.e it interconnects gNB to gNB and eLTE eNB to gNB and vice-versa. The Xn User plane (Xn-U) interface is defined as the interface between two NG-RAN nodes. It provides non-guaranteed delivery of user plane PDUs and supports functions like data forwarding, flow control, etc.

• AMF: 5G core Access and Mobility Management Function receives all the control and session-related information from the user equipment. It is responsible for the handling of connection and mobility-related tasks. It is connected to the SMF with the N11 interface. A mobile network comprises many AMF instances and each AMF is uniquely identified by GUAMI (Globally unique AMF identifier). It implements NAS (Non-Access Stratum) Ciphering and integrity protection algorithms. It is responsible for Lawful intercept, Access Authentication, and Authorization. It also performs Security context management.

• SMF: It is the fundamental element of the 5G core network architecture which is responsible for interacting with decoupled data planes, creating, updating, and removing PDU (Protocol data units). It manages the session context with the User plane function. The functions performed by SMF include UE IP address allocation and management, termination of interfaces, downlink data notifications, charging data collection, lawful intercept, roaming functionality, etc.

• UPF: It is the fundamental component of a 3GPP 5G Core Architecture. It represents the data plane evolution of a control and user plane separation (CUPS). The functions of UPF include QoS handling for the user plane, packet routing, and forwarding, packet inspection, lawful intercept for the user plane, traffic accounting and reporting, etc. 

• AUSF: It is an Authentication Server Function that performs the authentication of the user equipment. It is located in a home network. It makes the decision on UE Authentication for authenticating data and keying material like 5G AKA and EAP-AKA used. It is used to facilitate 5G security purposes.  

• NSSF: It is used by AMF for the selection of Network Slice Instances that will serve a particular device. It selects the Network Slice Instances determining the allowed network slice selection Assistance information (NSSAI). It can retrieve NRF, NSI ID, and target AMFs as a part of the UE registration process and PDU establishment process. 

• NEF: Network Exposure function facilitates secure, robust, developer-friendly access to network services. This function provides a means to securely expose the services and capabilities which are provided by 3GPP network functions. 

• NRF: Network Repository function works as a central repository for all the 5G network functions in the operator’s network. NRF allows 5G NF’s to register and discover each other with the help of standard APIs. It maintains the profiles of the available NF instances and their supported services in the 5G core network. Allows NF instances to track the status of other NF instances. 

• PCF: It supports the unified policy framework that governs the network behavior. It provides policy rules to enforce them. To facilitate this, the subscription information is gathered from the Unified data management function. It provides policy rules for control plane functions, which include network slicing, roaming, and mobility management. 

• UDM: It is a centralized way to control network usage data. It is cloud-native and designed for 5G technology. The functions of UDM are similar to HSS (Home Subscriber Service). It generates 5G AKA Authentication vectors, user identification handling,  this function stores the long-term security credentials used in Authentication for AKA. It stores subscription information. 

• AF: It requests dynamic policies and/or charging control. It performs operations like accessing the Network Exposure Function for retrieval of various resources. It interacts with PCF for policy control, application traffic routing, exposing services to end-users, etc.AF exposes the Application layer for interacting with 5G network resources. 



• DN: DN is a data network that is related to the 3GPP 5G Architecture. It could be operator services, internet access, or other services.