Unmanned Aircraft System Network Function

Description

The UAS NF (Unmanned Aircraft System Network Function) is a dedicated 5G core network function introduced in 3GPP Release 19 to provide native support for Unmanned Aircraft Systems (UAS) within mobile networks. It is specified primarily in TS 23.256 (architecture and procedures), TS 28.853 (management aspects), and TS 33.256 (security and authentication). The UAS NF acts as the central control point for aerial functionality, mediating between the 3GPP network, the UAV (Unmanned Aerial Vehicle), the UAV controller, and external UAS Service Suppliers (USS) such as those defined in the ASTM/3GPP remote identification ecosystem.

Architecturally, the UAS NF sits in the 5G Service Based Architecture (SBA) and exposes service-based interfaces (e.g., Nnrf-registered services) to other core network functions such as the AMF, SMF, UDM, NEF, and GMLC. It interacts with the AMF for registration and mobility events, with the SMF for PDU session establishment related to C2 (Command and Control) links, with the UDM for subscriber data, and with the NEF for exposure toward external USS/UTM (Unmanned Traffic Management) systems. The UAS NF also interfaces with the UAV itself and the UAV controller to perform UAV identification, authentication, and authorization before aerial services are granted.

Functionally, the UAS NF performs several critical roles. First, UAV identification: it validates the identity of the UAV and its controller, often using credentials provisioned by the USS or the 3GPP network. Second, authentication and authorization: it ensures that only authorized UAVs and controllers can establish C2 links and access UAS services, coordinating with the AUSF and UDM. Third, tracking: it maintains location and status information for the UAV, supporting both network-based positioning and UAV-reported location. Fourth, Remote Identification (RID): it supports the exchange of remote ID data required by aviation authorities, enabling law enforcement and air traffic management to identify drones in flight.

The UAS NF is a control-plane function and does not carry user-plane traffic itself; C2 and payload traffic flow through the UPF via PDU sessions. However, the UAS NF influences session establishment by authorizing C2 sessions and applying policies. It also supports the concept of UAS service authorization, where a UAV must be authorized before it can use network resources for flight. This authorization can be dynamic, reflecting the UAV's flight plan, operator credentials, and regulatory requirements.

In terms of deployment, the UAS NF can be instantiated as a standalone network function or integrated with other functions depending on operator choice. It is designed to be scalable and to support a large number of UAVs, which is important as drone operations grow. The UAS NF also plays a role in security, ensuring that UAV communications are protected and that only legitimate entities can control drones, preventing hijacking or spoofing. Overall, the UAS NF is a key enabler for integrating drones into 5G networks as first-class citizens, providing the necessary control, security, and management functions.

Purpose & Motivation

The UAS NF was created to address the growing need for cellular connectivity for Unmanned Aircraft Systems (UAS) in a standardized, secure, and manageable way. Before Release 19, drones could connect to mobile networks as generic devices, but there was no native support for UAV-specific requirements such as remote identification, C2 link authorization, and coordination with aviation authorities. This led to fragmented implementations and limited regulatory compliance. The UAS NF solves these problems by providing a dedicated core network function that handles UAV identification, authentication, authorization, tracking, and Remote Identification, enabling operators to offer UAS services that meet regulatory and safety requirements.

Historically, the integration of drones into airspace has been governed by aviation authorities (e.g., FAA, EASA) which require Remote Identification and tracking. Mobile networks are well-positioned to provide connectivity and location services for drones, but they needed a standardized way to expose these capabilities. The UAS NF, specified in 3GPP Release 19, provides this standardization, allowing interoperability between mobile operators, UAS Service Suppliers (USS), and UTM systems. It also addresses security concerns by ensuring that only authorized UAVs and controllers can establish C2 links, preventing unauthorized access and enhancing safety.

The UAS NF also enables new business models for operators, such as providing connectivity-as-a-service for drone operators, and supports the scalability needed for future mass drone operations. By defining a clear architecture and interfaces, 3GPP ensures that UAS NF can be deployed in multi-vendor environments and can evolve with future releases.