Toward enforcing network slicing on RAN: Flexibility and resources abstraction

Knowing the variety of services and applications to be supported in the upcoming 5G systems, the current "one size fits all" network architecture is no more efficient. Indeed, each 5G service may have different needs in terms of latency, bandwidth, and reliability, which cannot be sustained by the same physical network infrastructure. In this context, network virtualization represents a viable way to provide a network slice tailored to each service. Several 5G initiatives (from industry and academia) have been pushing for solutions to enable network slicing in mobile networks, mainly based on SDN, NFV, and cloud computing as key enablers. The proposed architectures focus principally on the process of instantiating and deploying network slices, while ignoring how they are enforced in the mobile network. While several techniques of slicing the network infrastructure exist, slicing the RAN is still challenging. In this article, we propose a new framework to enforce network slices, featuring radio resources abstraction. The proposed framework is complementary to the ongoing solutions of network slicing, and fully compliant with the 3GPP vision. Indeed, our contributions are twofold: a fully programmable network slicing architecture based on the 3GPP DCN and a flexible RAN (i.e., programmable RAN) to enforce network slicing; a two-level MAC scheduler to abstract and share the physical resources among slices. Finally, a proof of concept on RAN slicing has been developed on top of OAI to derive key performance results, focusing on the flexibility and dynamicity of the proposed architecture to share the RAN resources among slices.