Multi-operator Inter-network Roaming Networking Solution and Trials

Since 5G networks are expensive in terms of equipment, require large investments during construction, consume large amounts of power and have high operating costs, co-location and sharing have become a new approach to operator network development and operation. This paper first introduces the networking architecture and interoperability interface of inter-network roaming in core networks, followed by the key procedures and specifications of inter-network roaming, and then analyzes the registration procedures and terminal mobility management in roaming areas. Finally, a proposal for inter-network roaming commercialization is presented, and the correctness and feasibility of the scheme are verified through interactive experiments between home 4G and visited 5G as well as between home 5G and visited 5G.

I. Introduction

Construction of 5G networks, which use mobile technology, is a significant component of China’s new infrastructure development. The Party Central Committee and the State Council have regularly issued significant directives to hasten the building of 5G networks and other new infrastructure because they place great significance on the joint creation and sharing of these networks. Currently, China Mobile and China Radio and Television have begun to carry out co-building and sharing in 5G access network and bearer network, and China Telecom and China Unicom have already accomplished the common construction and sharing of 5G network access network [1]. While 700 MHz is known as the “golden frequency band” for wireless network coverage, with benefits of low propagation loss, wide coverage, and low network cost, it can significantly reduce the number of base stations compared to 3.5 GHz/2.6 GHz [2]. The current 5G network frequency is high frequency, with large penetration loss, difficult continuous coverage, dense network sites, and high equipment unit price. The Ministry of Industry and Information Technology (MIIT) has started discussions on the roaming scheme of four operators’ inter-network from June 2019 to realize the co-development of 5G networks, in order to implement the decision and deployment of the Party Central Committee and the State Council on accelerating 5G development, promote open sharing of 5G networks, reduce duplicate construction, and achieve 5G network coverage and business development in an intensive and efficient manner [3], [4].