Take Your Cell a Walk for Ultra-Low e2eDeiay in Software Defined Vehicular Networks

Recently, to handle end to end mobility and to reduce the OPEX/CAPEX costs of vehicular networks, Handover management is executed with network service chain by virtual Evolved Packet Core (vEPC) thanks to Network Function Virtualization (NFV). However; as the number of Handover requests has increased in an ultra-dense topology with a high number of road side units (RSUs), the SDN/NFV controller has become a bottleneck with an increased response time to a vehicle. In this paper, we investigate the following research question: How to reach few milliseconds end-to-end Delay (e2eDelay) for Ultra-Reliable and Low Latency (URLLC) services in 5G vehicular networks? Therefore, we propose a new SDN/NFV based Handover management without disrupting the centralized manner of SDN controller. To do this, we define a logical and physical coverage area of RSUs with two newly redesigned VNFs named as Smallcell and Macrocell virtual Network Functions (SvNF, MvNF). The former one is for serving vehicle on RSU as a smallcell via physical coverage; whereas the latter one is for forwarding data packets over the same RSU that is a macrocell via logical coverage without any Handover request. E2eDelay is monitored by the proposed queuing theoretic formula in a novel Handover Triggering Algorithm which checks the length of the service chain and determines the optimal time to run Handover network function. According to performance results, the proposed SDN/NFV architecture offers 12 milliseconds reduced e2eDelay, by keeping it under 5G requirements (a few milliseconds) with the service chain up to 7 lengths and keeping the centralized manner of SDN.