Enhanced C-RAN Architecture Supporting SDN and NFV Functionalities for D2D Communications

Future Fifth Generation (5G) cellular systems will be characterized by ultra-dense areas, where users are gradually asking for new multimedia applications and hungry-bandwidth services. Therefore, a promising solution to boost and optimize this future wireless heterogeneous networks is represented by the Cloud Radio Access Network (C-RAN) with the joint use of Software Defined Networking (SDN) and Network Function Virtualization (NFV). In such a scenario, low power base stations and device-to-device communications (D2D), involved into traditional cellular network, represented a possible solution to offload the heavy traffic of macrocells, while guaranteeing user experience as well. Nevertheless, the high centralization and the limited-capacity backhauls makes it difficult to perform centralized control plane functions on a large network scale. To address this issue, we investigate the integration of two enabling technologies for C-RAN (i.e., SDN and NFV) in the current 5G heterogeneous wireless architecture in order to exploit properly proximity-based transmissions among devices. Then, in order to validate the applicability of our proposed architecture, we consider the case of D2D pair handover where we show that our solution is able to decrease the number of signaling messages needed to handoff the D2D pair from a source to a target base station and, at the same time, the time execution for the entire handover process.