Research On Content Dissemination Scheme And Downloading Task Scheduling In Internet Of Vehicles

Internet of Vehicles(IoV)applies advanced communication technologies to the transportation system.Utilizing vehicle-to-vehicle,vehicle-to-infrastructure,vehicle-topedestrian,and vehicle-to-networks communications,IoV provides multiple types of applications related to safety,efficiency,and entertainment to users.IoV promotes the rapid development of intelligent transportation systems,which causes wide public concern.Apparently,the effective dissemination of content,e.g.,texts,images,music and video clips is the basis of any type of applications in IoV.Due to the high mobility of vehicles and intermittent vehicle-to-vehicle(V2V)and vehicleto-infrastructure(V2I)communications,the data download volume of individual vehicle is quite limited.Besides,the dark areas resulting from sparse deployment of infrastructure extremely restrict the efficiency of content dissemination.When a target vehicle cannot complete the content download within current coverage of infrastructure,it has to wait for next infrastructure access to continue the unfinished downloading,which leads to long delay and poor use experience.Furthermore,due to the limited communication resources,when multiple vehicles requests to download content simultaneously,infrastructure can not provide services to all vehicles.Therefore,a data access scheduling scheme is necessary to improve service capacities of the entire networks.The main research work of this thesis consists of two parts,which are stated as follows.Firstly,this thesis proposes a cooperative content dissemination scheme,which exploits the combination of both clustering and carry-and-forward strategies,coordinates the cooperation of multiple infrastructures,cluster formation in the same direction and data forwarding of reverse vehicles to facilitate the target vehicle to download large-size content.On this basis,detailed theoretical analysis framework is established to characterize the collaborative download process.Simulation and numerical results show the significant benefits of the proposed scheme in terms of increasing data download volume.Moreover,the results are of great value in guiding the effective dissemination of target content among multiple infrastructures and vehicles.In addition,this thesis proposes an Integrity-Oriented Downloading Scheduling(IODS) scheme for vehicle to infrastructure data access,which provides a fundamental solution to the performance enhancement of data access of multiple users in terms of service ratio.IODS firstly estimates whether the data request can be served completely to avoid the invalid data access.Then the priorities of vehicles are determined considering vehicles' mobility pattern and characteristics of requests,such as deadline and data size.The proposed data access approach can be greatly helpful to boom the entire networks.