NR Femto Hosting Party

Description

The NR Femto Hosting Party is a concept introduced in 3GPP Release 19 to define the role of an entity that has a contractual relationship with a mobile network operator for the deployment of NR Femto nodes. An NR Femto node is a small, low-power cellular base station that operates in licensed spectrum to provide improved coverage and capacity in indoor or localized environments. The Hosting Party is responsible for the physical deployment and management of these nodes, while the operator provides the spectrum and core network connectivity. This concept is specified in TS 23.501 (System architecture for the 5G System) and TS 33.745 (Security aspects of NR Femto).

In the 5G architecture, the NR Femto Hosting Party plays a crucial role in the context of Closed Access Group (CAG) as defined in clause 5.50 of TS 23.501. A CAG is a group of subscribers who are permitted to access one or more CAG cells, which are typically deployed in private or semi-private environments such as enterprises, campuses, or homes. The NR Femto Hosting Party acts as the CAG owner, meaning it is responsible for managing the list of authorized users and ensuring that only those users can access the femto nodes. This allows the Hosting Party to offer private network services to its employees or customers while leveraging the operator's licensed spectrum and core network.

The relationship between the NR Femto Hosting Party and the operator is governed by a contract that specifies the terms of service, including spectrum usage, security requirements, and quality of service. The Hosting Party may be an enterprise, a building owner, or a third-party service provider. The operator remains responsible for the overall network management and security, while the Hosting Party handles the local deployment and user administration. This model enables operators to extend coverage and capacity without significant capital expenditure, while Hosting Parties gain access to reliable cellular connectivity for their premises.

From a technical perspective, the NR Femto Hosting Party interacts with the 5G core network through the NR Femto node, which connects via the N2 and N3 interfaces to the AMF and UPF, respectively. The Hosting Party may use a management system to configure the CAG and manage user subscriptions. Security is a critical aspect, as specified in TS 33.745, which defines the security procedures for NR Femto, including authentication, authorization, and encryption. The Hosting Party must ensure that the femto nodes are physically secure and that the CAG list is accurately maintained to prevent unauthorized access.

The introduction of NR Femto Hosting Party in Release 19 reflects the growing demand for private 5G networks and the need for a standardized framework to support them. It allows operators to offer new business models, such as neutral host services, where multiple operators can share the same femto infrastructure. The Hosting Party concept also facilitates the deployment of 5G in environments where macro coverage is insufficient, such as indoor hotspots, factories, and stadiums. As 5G evolves, the role of the Hosting Party is expected to expand, enabling more flexible and scalable network deployments.

Purpose & Motivation

The NR Femto Hosting Party concept was created to address the need for a clear contractual and technical framework for deploying small cells in private or semi-private environments. Before its introduction, the deployment of femto cells was often ad-hoc, with unclear responsibilities between the operator and the premises owner. This led to challenges in security, user management, and service assurance. The Hosting Party role solves these issues by defining a formal relationship and assigning specific responsibilities, particularly as the CAG owner.

The concept also supports the growing trend towards private 5G networks, where enterprises want dedicated coverage and control over their users. By allowing a third party to act as the CAG owner, operators can delegate user management while retaining control over the spectrum and core network. This enables new business models and accelerates the deployment of 5G in indoor and localized areas.

Furthermore, the NR Femto Hosting Party facilitates regulatory compliance and security. The contract with the operator ensures that the Hosting Party adheres to national regulations and 3GPP security standards. The CAG mechanism ensures that only authorized users can access the femto nodes, protecting the operator's network from unauthorized use. As 5G networks become more dense and heterogeneous, the Hosting Party role will be essential for managing the complexity of small cell deployments.