Software Defined Radio Access Network Sharing by Multi-Operator Core Networks

Multi-Operator Core Network (MOCN) is a radio access network (RAN) sharing scheme among multiple mobile network operators (MNOs), featured by the need that precious radio resources are shared by multiple dedicated core networks to achieve capital and operational cost reductions. The paper presents a study on a software-defined scheme of MOCN (SD-MOCN) to flexibly configure and control the radio resource allocation, in units of resource block group (RBG), based on a service level agreement (SLA) of RAN sharing among dedicated MNOs. The proposed SD-MOCN has been successfully realized with a RAN emulator, connected with and shared by two physical LTE core networks (CNs) with unique public land mobile network (PLMN) identities. Such a successful realization is showcased with both the functional and performance tests. Functionally speaking, cellular phones of each dedicated CN can successfully be connected with their associated PLMN core network via one RAN slice. Performance-wise, each MNO can reach its slice-based throughput and goodput linearly proportional to the number of allocated RBGs, considering the performance reduction factors caused by the effects of both the modulation/coding induced spectral efficiency and transmission overheads of user/control planes. The preliminary results of performance tests contribute three key effects: (1) slice isolation, (2) slice performance linearity, and (3) slice reduction factor linearity, where effect (1) can guarantee management independence of multiple dedicated CNs sharing a single RAN, effect (2) can ensure the linear response of a given RAN slice with respect to its allocated RBGs, according to the SLA planning for its dedicated CN, and effect (3) indicates that the performance reduction factors of the system-level throughput and goodput are both linearly applicable to the prediction of the slice-level throughput and goodput.