NF Uncrewed Aerial System Network Function

Description

The NF Uncrewed Aerial System Network Function (UAS NF) is a core network element introduced by 3GPP to support Uncrewed Aerial Systems (UAS), commonly known as drones, over 3GPP networks (4G LTE and 5G). It is part of the service-based architecture (SBA) in the 5G Core network, operating as a specialized Network Function (NF) that interacts with other core NFs like the Unified Data Management (UDM), Network Exposure Function (NEF), and Policy Control Function (PCF). The primary role of the UAS NF is to authorize UAS operations, manage UAS service subscriptions, and facilitate communication between the UAS Service Supplier (USS), the UAS operator, and the 3GPP network.

Architecturally, the UAS NF acts as a central control point. It authenticates and authorizes a UAS (comprising the Uncrewed Aerial Vehicle - UAV - and its Remote Controller) before allowing it to access network services for command & control (C2) and payload data links. It interfaces with the USS/UTM (UAS Traffic Management) system, which is the external service provider managing airspace and flight approvals. The UAS NF relays flight authorization requests from the UAS operator (via the UE) to the USS and enforces the authorization decisions received. It also supports location reporting of UAVs to the USS for airspace awareness and can apply specific QoS policies for UAS traffic through the PCF.

Key components of the UAS service framework include the UAS NF itself, the UAS service subscription profile stored in the UDM, and the service interfaces (e.g., Nuu, Nudm, Nnef). The UAS NF works by first validating the UAS identity and subscription. For a flight operation, it receives a UAS flight authorization request, potentially including the planned flight path. It forwards this to the authorized USS. Upon receiving approval, the UAS NF may instruct the network to establish dedicated QoS flows for the C2 link with high reliability and low latency guarantees. It also supports continuous or triggered location reporting during the flight. This end-to-end management enables beyond visual line-of-sight (BVLOS) operations by providing a secure, tracked, and network-managed communication link.

Purpose & Motivation

The UAS NF was created to address the growing need for safe, scalable, and regulated integration of drones into national airspace using ubiquitous cellular networks. Prior to its specification, drones used direct point-to-point radio links (e.g., Wi-Fi) with limited range, no inherent network-based authorization, and no integration with air traffic management systems. This posed safety, security, and scalability challenges for commercial drone applications. The 3GPP network provides wide-area coverage, robust security, mobility support, and high capacity, making it an ideal candidate for UAS connectivity.

The motivation for standardizing the UAS NF stemmed from regulatory pushes worldwide (e.g., by FAA, EASA) requiring remote identification, geofencing, and traffic management for drones. 3GPP initiated work to define network support for UAS to enable compliant commercial services. The UAS NF solves the problem of how a mobile network can authenticate a drone as a legitimate user, authorize its specific flight, and provide the necessary quality of service and location tracking services demanded by regulators and UAS service providers.

It addresses the limitations of ad-hoc connectivity by providing a standardized, secure framework. This framework allows a single drone operator to manage a fleet across wide geographic areas using existing cellular infrastructure, enables seamless handover between cells during flight, and ensures that critical C2 links are protected and prioritized. The creation of the UAS NF in 3GPP Release 15 and its enhancements in later releases represent a pivotal step in enabling advanced drone services like package delivery, infrastructure inspection, and aerial surveillance at scale.