A Framework for Roaming between 5G Non-Public-Networks (NPNs)

The use of 5G private networks is gaining popularity in the industry due to their capability to address the requirements of a large number of vertical markets including own administration and communication privacy and security. These locally administrated networks are similar to micro-operators, providing low delay, high capacity, and reliable communication to the local devices. However, these networks will need to interact with each other in order to extend coverage and provide connectivity to visiting devices. In this article, a roaming framework addressing geographically distributed private networks is proposed, by adapting the 5G roaming system of the large-scale operators to a federated authentication and authorization framework. To realize the proposed solution, the Fraunhofer FOKUS Open5GCore toolkit is extended with the proposed architectural extension and it is then evaluated on the basis of flexibility and privacy of deployment, backhaul usage, and reduced network administration underlining its feasibility for further development.