A Study On Deployment And Energy Efficiency Of Roadside Relay Unit For Vehicular Ad Hoc Networks

Vehicular Ad Hoc Network (VANET) is a special type of of mobile ad hoc networks for vehicular communcation. In recent years, it has received a great amount of attention from both industry and academia because of the road safety and environmental pollution problems. A VANET consists of moving vehicles installed with on board units (OBUs) and roadside units (RSUs) deployed along a road, and can be used to provide safety applications and functionality applications. This thesis studies the RSU energy efficiency problem in VANET, and analyzes the energy efficiency and information delivery delay of a roadside relay point (RP) deployment in a highway road scenario.First, the thesis briefly introduces the architecture, characteristics, applications, current research status and future research directions of VANET, and discusses the connectivity problem in VANET. Then, it introduces a new RSU deployment, i.e., to uniformly deploy a certain number of low-cost devices with simple relaying functionality between two neighbor RSUs as relay points (RPs) for vehicle-to-vehicle (V2V) communication to improve the network connectivity.Secondly, the thesis studies the energy efficiency problem of the RP deployment and derives a mathematical model to analyze the impacts of the vehicle transmission radius and the vehicle arrival rate on the average number of RPs that need to be turned on for information delivery and the average amount of RP energy that can be saved without affecting information delivery. The accuracy of the derived mathematical model is validated through simulation results. Moreover, the simulation results show that under a fixed vehicle transmission radius, the energy efficiency of the RP deployment increases with the vehicle arrival rate increasing, and under a fixed vehicle arrival rate, the energy efficiency of the RP deployment increases with the vehicle transmission radius increasing.Finally, the thesis studies the information delivery delay problem of the RP deployment and derives a mathematical model to calculate the information delivery delay between two neighbor RSUs. In deriving the mathematical model, it first derives the average speed of the vehicles at the front end of a cluster and the average speed of the vehicles at the rear end of a cluster, respectively, by analyzing the vehicle clustering on the road and the two different information delivery processes. Then, the information delivery delay between two neighbor RSUs is obtained. The accuracy of the mathematical model is validatd through simulation results.