5G introduces a new Core Network called the 5G Core (5GC) for the 5G System (5GS). This is an evolution of the Evolved Packet Core (EPC) in the 4G Evolved Packet System (EPS).
In many instances today, 5G is implemented only in the Radio Access Network (RAN) and used in conjunction with 4G RAN and EPC. This deployment is called 5G Non-Standalone (NSA).
As operators start to deploy 5G Cores, they may decide to transition to 5G Standalone (SA), either fully, or running alongside 5G NSA networks.. A number of factors will influence this choice, including – but not limited to - the kind of architecture selected, the amount of spectrum held, planned services, and target use cases and sectors.
Most operators will also support different types of private networks and may offer end-to-end solutions as part of their portfolio. These private networks can be based on 4G or 5G and typically contain the radio access and core network. A lightweight solution can contain all the core functionality in a single small server, often referred to as a network-in-a-box (NIB).
These private networks require a high level of privacy and security regardless of whether data is stored on premise or in the cloud.
3GPP specifies security as mutual authentication of nodes, identity protection, integrity protection and ciphering, but with the transition to Open RAN and cloud, additional levels of security are required to ensure that networks perform reliably and securely.
One approach widely supported in the industry is Zero Trust Architecture (ZTA), rooted in the principle of “never trust, always verify”. If an intruder manages to get in the network, damage is limited by blocking unauthorised access to network resources while at the same time limiting internal lateral movement of data.
With the frequent introduction of new architectures, approaches and infrastructure, security should always be a top priority during planning, design, deployment, configuration and testing.
For core networks, end-to-end solutions and security therefore, the key issues for Open RAN are:
- Reliability and security
- Ownership and resolution of network faults
- Interoperability across public and private networks
- Interoperability across domains like terrestrial and non-terrestrial
- Business model for new deployment models
FRANC (Future RAN Competition) run by DSIT, has allocated up to £30 million of R&D funding to projects that support the goals of the government's 5G Supply Chain Diversification Strategy. The competition aims to help to incentivise industry to create new products and services to unlock the full potential of Open RAN. Several of these projects are exploring core networks, end-to-end solutions and security:
FRANC academic partners in this area:
- University of Bristol: their 5G Test Network has been designed to provide a multi-tenancy cloud network infrastructure with its resources including a mix of proprietary and open-source network functions, and interfaces using multi-vendor end-to-end network solutions. They are part of both the O-RANOS and Proteus projects.
- University of Surrey: focus on developing fundamental research through to practice in the interdisciplinary area of antennas and propagation, signal processing, mmWave and 'internet of things' technologies for mobile and satellite applications, and aim to bring digital closer to the RF and antennas. They are part of the Flex-5G project.
- University of Warwick: part of the 5G Drive project that aims to develop a 5G Open & Diversified RAN Integration solution for private mobile networks, that is low cost, secure, and capable of integrating with public networks.
The following commercial organisations are actively undertaking R&D into Open RAN in the core networks, end-to-end solutions and security space, through the FRANC projects.
