The upcoming Fifth Generation (5G) mobile network aims to support a wide variety of services. In addition to the four standardized service use cases, network operators are also looking for the ability to deploy newer services in shorter timescales to quickly monetize the 5G network. This has resulted in the emergence of Software-Defined Networking (SDN) and Network Function Virtualization (NFV) as key technologies for designing the 5G networks. In this paper, we provide a survey of some of the promising SDN/NFV-based architectures for the Radio Access Network (RAN) and highlight how these architectures can be utilized to support features like network virtualization and slicing. We also identify the gaps which need to be addressed by these proposals to be able to support the 5G network capabilities and list a few considerations for slicing the 5G RAN. Finally, we propose Virtualized RAN (VirtRAN), a recursive SDN/NFV-based architectural framework for RAN, which addresses some of these gaps and can be used to support features like network slicing and user mobility management in 5G networks in an efficient manner.

中文翻译：

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VirtRAN：基于 SDN/NFV 的 5G RAN 切片框架

即将推出的第五代 (5G) 移动网络旨在支持各种服务。除了四种标准化服务用例外，网络运营商还寻求能够在更短的时间范围内部署更新的服务，以快速通过 5G 网络获利。这导致了软件定义网络 (SDN) 和网络功能虚拟化 (NFV) 作为设计 5G 网络的关键技术的出现。在本文中，我们对无线接入网络 (RAN) 的一些有前途的基于 SDN/NFV 的架构进行了调查，并重点介绍了如何利用这些架构来支持网络虚拟化和切片等功能。我们还确定了这些提案需要解决的差距，以便能够支持 5G 网络功能，并列出了对 5G RAN 进行切片的一些注意事项。最后，我们提出了虚拟化 RAN (VirtRAN)，这是一种基于递归 SDN/NFV 的 RAN 架构框架，它解决了其中一些差距，可用于以有效的方式支持 5G 网络中的网络切片和用户移动性管理等功能。