The upcoming Sixth Generation (6G) mobile communications system envisions supporting a variety of use cases with differing characteristics, e.g., very low to extremely high data rates, diverse latency needs, ultra massive connectivity, sustainable communications, ultra-wide coverage etc. To accommodate these diverse use cases, the 6G system architecture needs to be scalable, modular, and flexible; both in its user plane and the control plane. In this paper, we identify some limitations of the existing Fifth Generation System (5GS) architecture, especially that of its control plane. Further, we propose a novel architecture for the 6G System (6GS) employing Software Defined Networking (SDN) technology to address these limitations of the control plane. The control plane in existing 5GS supports two different categories of functionalities handling end user signalling (e.g., user registration, authentication) and control of user plane functions. We propose to move the end-user signalling functionality out of the mobile network control plane and treat it as user service, i.e., as payload or data. This proposal results in an evolved service-driven architecture for mobile networks bringing increased simplicity, modularity, scalability, flexibility and security to its control plane. The proposed architecture can also support service specific signalling support, if needed, making it better suited for diverse 6GS use cases. To demonstrate the advantages of the proposed architecture, we also compare its performance with the 5GS using a process algebra-based simulation tool.

翻译：即将到来的第六代（6G）移动通信系统旨在支持具有不同特性的多样化应用场景，例如从极低到极高的数据速率、多样化的时延需求、超大规模连接、可持续通信及超广域覆盖等。为适应这些多样化场景，6G系统架构需在用户面与控制面同时具备可扩展性、模块化与灵活性。本文首先分析了现有第五代系统（5GS）架构的若干局限性，尤其聚焦于其控制平面。进而，我们提出一种采用软件定义网络（SDN）技术的第六代系统（6GS）新型架构，以解决控制平面的现有缺陷。当前5GS控制平面承载着两类功能：终端用户信令处理（如用户注册、认证）以及用户面功能的控制。我们建议将终端用户信令功能从移动网络控制平面剥离，并将其视为用户服务（即作为载荷或数据处理）。该方案催生了一种演进的面向服务的移动网络架构，使其控制平面在简洁性、模块化、可扩展性、灵活性与安全性方面得到显著提升。所提架构在必要时还可支持特定服务的信令处理，从而更好地适配多样化的6GS应用场景。为验证该架构的优势，我们使用基于进程代数的仿真工具将其性能与5GS进行了对比分析。