Juergen Rochol

Future mobile networks are envisioned to become multi-service systems, enabling the dynamic deployment of services with vastly different performance requirements, accommodating the needs of diverse service providers. Virtualizing the mobile network infrastructure is of fundamental importance for realizing this vision in a cost-effective manner. While there have been extensive research efforts in virtualization for the mobile core network, virtualization in the radio access network (RAN) is still at an early stage. In this paper, we present AIRTIME, a new RAN slicing system that enables the dynamic on-the-fly virtualization of RANs, with the programmability required by service providers to customize any aspect of their virtual RAN to meet their service needs. We present a prototype implementation of AIRTIME and evaluate the: (I) capacity to create virtual RANs on-the-fly, (II) performance experienced by slice owners, (III) isolation among multiple virtual RANs sharing the same physical infrastructure, and (IV) scalability to accommodate a large number of virtual RANs.

Network slicing is one of the key enabling techniques for 5G, allowing Mobile Network Operators (MNOs) to support services with diverging requirements on top of their physical network infrastructure. The MNOs should be able to offer Network Slices (NSs) as a Service (NSaaS) and provide customisable and independent virtual networks to tenants. In this paper, we address the functionality and challenges for enabling Radio Access Network (RAN) as a Service (RANaaS) through radio virtualisation. We analyse the requirements for using radio hypervisors to support RANaaS, and we evaluate how the current state-of-the-art on radio virtualisation meets such requirements. We identify, formalise and address the key resource management functionality missing from existing radio hypervisors. Then, we present eXtensible Virtualisation Layer (XVL), a software layer that provides the missing resource management functionality for enabling RANaaS and can be added on top of existing radio hypervisors. We integrated XVL with a radio hypervisor, forming a RANaaS platform that can provision heterogeneous RAN slices as a service. We outline XVL's architecture and design choices, as well as evaluate its performance in terms of the computational overhead, the delay to provision virtual radios, the delay introduced to forward IQ samples, and the signal degradation. Our results show that XVL enables leveraging existing radio hypervisors for supporting the RANaaS paradigm.

A wide range of multimedia services is expected to be offered for mobile users via various wireless access networks. Even the integration of Cloud Computing in such networks does not support an adequate Quality of Experience (QoE) in areas with high demands for multimedia contents. Fog computing has been conceptualized to facilitate the deployment of new services that cloud computing cannot provide, particularly those demanding QoE guarantees. These services are provided using fog nodes located at the network edge, which is capable of virtualizing their functions/applications. Service migration from the cloud to fog nodes can be actuated by request patterns and the timing issues. To the best of our knowledge, existing works on fog computing focus on architecture and fog node deployment issues. In this article, we describe the operational impacts and benefits associated with service migration from the cloud to multi-tier fog computing for video distribution with QoE support. Besides that, we perform the evaluation of such service migration of video services. Finally, we present potential research challenges and trends.