Research On Integration And Optimization Of Parked Vehicle Resources In VANET

The demand for the data transmission of the IoV is increased with the continuous development of the automobile industry,which also puts forward higher requirements on the capacity and QoS of the communication system.There are two main problems in VANET communications: i)the shadow effect caused by the complex geographical environment in urban areas which leads to a significant degradation in transmission signals;and ii)the reduction in the number of moving vehicles at a particular location or time(e.g.,in the suburbs or at night)on the road,will limit the long-distance communication between vehicles.Therefore,the existing VANET resources,such as mobile vehicles and roadside units can not guarantee the quality of vehicle-to-vehicle communications.The statistics show that the number of parked vehicles is much larger than that of moving vehicles and parked vehicles are mostly parked next to buildings.Therefore,some scholars have proposed to add the parked vehicles into VANET as communication resources to address the problems mentioned above.However,there are still many deficiencies in the current research,such as the lack of efficient routing protocols and energy-saving mechanisms for these parked vehicles.Therefore,the author of this thesis has conducted thorough analysis on these two problems and proposed the efficient algorithms.The main contributions of this thesis are as follows:(1)For the parked-vehicle-assist relay routing communication in VANET,this author proposes a Parked Vehicle Assisted Relay Routing Algorithm which is composed by four parts,i.e.,periodic Hello packet exchange mechanism,candidate relay list update,communication link quality evaluation and candidate relay list selection.The algorithm first interacts with nearby vehicles through periodically broadcasting Hello packets,then uses the candidate relay list update algorithm to maintain the list of candidate relay vehicles,and then evaluates the quality of all links through communication link quality estimation algorithms.Finally,the candidate relay list selection algorithm is used to select the vehicles that need to be relayed from the candidate vehicle list.Simulations show that the proposed algorithm can significantly improve the end-to-end packet delivery rate and delivery quality,as well reduce the delivery delay of data packets to some extent.(2)For the energy-saving in parked-vehicle-assist relay routing communications,the author proposes a dynamic energy-saving scheduling algorithm for parked vehicles,which consists of parked vehicles relay selection algorithm and parked vehicles dynamic working algorithm.The algorithm firstly clusters the moving vehicles on the road according to the connectivity,and then uses the parked vehicles relay selection algorithm to select the parked vehicles that has to work as communication relay from the parked vehicles on both sides of the road.Finally,the dynamic working algorithm is used to dynamically adjust the working mode of the selected parked vehicles according to the current service demand and the remaining power of the vehicle.The simulations show that the proposed algorithm can dynamically select the relay vehicles according to the density of the moving vehicles and parked vehicles,and reasonably adjust the working mode of the parked vehicles according to the service demand,which greatly improves the energy efficiency of parked vehicles.