Applying SDN to Mobile Networks: A NewPerspective for 6G Architecture

The upcoming Sixth Generation (6G) mobile communications system envisions supporting a variety of usage scenarios with differing characteristics, e.g., immersive communication, hyper reliable and low-latency communication, ultra massive connectivity, ubiquitous connectivity, haptic communications etc. To accommodate such diverse scenarios, the 6G System (6GS) architecture needs to be scalable, modular, and flexible. In this paper, we identify some architectural limitations of the Third Generation Partnership Project (3GPP) defined Fifth Generation System (5GS), especially that of its control plane. Further, we propose a novel architecture for the 6GS to address these limitations. Among the different functionalities of the 5GS control plane, two key functionalities are the signalling exchange with end user devices (e.g., for user registration and user authentication) and control of user plane functions. We propose to move the “signalling handling functionality” out of the mobile network control plane and treat it as user service and signalling messages as payload or data. We think this approach is better aligned with the SDN paradigm. This proposal results in an evolved service-driven architecture for mobile networks where almost all communication with an end user (and device), including the signalling exchange, is treated as service. We explicate that the proposed architecture brings increased modularity, scalability, and flexibility to its control plane. We also compare its performance with the 5GS using a process algebra-based simulation tool.