On the Benefits of RAN Virtualisation in C-RAN Based Mobile Networks

With ever growing data traffic the traditional mobile network architecture is struggling to cope. Network densification using heterogeneous networks supported by Cloud-RAN is one of the core concepts in terms of physical resources. The system achieves increased capacity by reducing the number of devices (commonly refered to as user equipment - UE) connected to any individual cell. Cloud-RAN decouples the baseband processing from the radio units, allowing the processing power to be pooled at a central location thus reducing the required redundancy. The decoupling also supports innovation in many other RAN technologies by simplifying intercell coordination. While Cloud-RAN differs significantly from traditional base station architectures, interactions with the core network do not reflect these differences. We argue that there is a strong need for an intermediate stage that will reconcile the core network and Cloud-RAN. In this paper we propose a virtual network architecture for Cloud-RAN base stations that will allow us to present the core network with an abstracted view of the physical network. By logically grouping macro cells with collocated small cells we can provide the core network with a simplified overview, reducing signalling overhead. Meanwhile, low latency decisions, such as cell load balancing and interference management, can be made entirely within the Cloud-RAN base station. We present practical applications of the proposed scheme and assess its interoperability with other improvements to the wider infrastructure proposed in related works. The principles presented in this paper lend themselves to evolving key concepts and themes for future 5G networks and beyond.