Radio Access Network Operator

Description

The Radio Access Network Operator (RAN Operator) is a business and technical role defined in 3GPP specifications. It refers to an operator that offers radio access to one or more core network operators (CN operators). This concept supports architectures where the radio access network and the core network are owned and operated by different entities. It is a key enabler for network sharing, wholesale access, and the separation of infrastructure from service provision. The RAN Operator owns or controls the radio access infrastructure—such as base stations, antennas, and backhaul—and provides connectivity to subscribing core network operators, which in turn serve end users.

The role of the RAN Operator is closely tied to the architectural separation between the access network and the core network. In traditional deployments, a single operator owns both the RAN and the CN. However, 3GPP has long recognized scenarios where these functions are split. For example, in a Multi-Operator Core Network (MOCN) configuration, a single radio access network is shared by multiple core networks, each belonging to a different operator. The RAN Operator provides the shared radio resources and manages the allocation and isolation of those resources among the participating core network operators. This requires standardized mechanisms for broadcasting multiple PLMN identities, routing messages to the correct core network, and ensuring fair resource usage.

From a technical standpoint, the RAN Operator role entails responsibilities in the areas of radio resource management, network planning, and operations and maintenance. The RAN Operator must decide how to partition radio capacity among core network operators, how to handle priority and pre-emption, and how to meet different quality-of-service or regulatory requirements. The 3GPP specifications, particularly TS 22.951 (Service aspects and requirements for network sharing), define the requirements and architectural models for network sharing, including the roles of the RAN Operator and the core network operators. These models support various sharing scenarios, such as geographically split sharing, where each operator has its own radio equipment in different areas, or fully shared RAN, where a common radio access network serves all partners.

The RAN Operator role also affects mobility management. When a UE moves within the shared radio access network, it may need to attach to its home core network, which is selected based on the PLMN identity broadcast by the cell. The RAN Operator must ensure that the radio access network correctly routes control-plane and user-plane traffic to the appropriate core network. This involves support for multiple PLMN IDs in system information and for the selection of the correct core network node (e.g., MME or AMF) during initial attach or handover. In this way, the RAN Operator acts as a neutral host, providing access to multiple service providers.

In summary, the Radio Access Network Operator is a foundational concept for shared and wholesale radio access. It allows new business models where infrastructure providers and service providers are distinct entities, promoting competition and efficient use of spectrum and sites. The definition has remained stable across 3GPP releases from R99 to Rel-19, underscoring its enduring relevance. As networks evolve toward 5G and beyond, with concepts like neutral host networks, private networks, and RAN sharing, the role of the RAN Operator continues to be a vital part of the 3GPP framework.

Purpose & Motivation

The concept of a Radio Access Network Operator was created to support regulatory and commercial frameworks where the entity that owns the radio access infrastructure is different from the entity that provides services to end users. This separation enables infrastructure sharing, which can reduce deployment and operational costs, accelerate coverage expansion, and make more efficient use of scarce spectrum and sites. Without a standardized role for a RAN Operator, multi-operator sharing would rely on proprietary solutions, leading to interoperability problems and hindering competition.

Historically, mobile networks were vertically integrated, with a single operator owning both radio and core networks. However, as markets liberalized and spectrum became more expensive, operators sought ways to share infrastructure. 3GPP addressed this need by defining architectural models in specifications such as TS 22.951 and TS 23.251, which introduced concepts like Multi-Operator Core Network (MOCN) and Gateway Core Network (GWCN). The RAN Operator role is central to these models, as it establishes the entity responsible for offering radio access to multiple core network operators.

The term has proven durable because it captures a flexible business relationship rather than a specific technical implementation. It applies to 2G, 3G, 4G, and 5G networks, and to various sharing configurations, from passive sharing (site and mast sharing) to active sharing (spectrum, base station, and even core network elements). As 5G introduces network slicing and private networks, the RAN Operator concept remains relevant for wholesale access and neutral host models. The original wording from R99, "Operator that offers radio access to one or more core network operators," has been retained essentially unchanged, reflecting the stability of the underlying principle.