Research On The Optimization Of Information Dissemination In Internet Of Vehicles

Transportation systems,responsible for carrying people and goods with safety and efficiency,have great impacts on our daily lives and the modern societies.Recently,with the growing need of the fast,safe,efficient transportation,the transportation systems have encountered great challenges.Thanks to the explosive development of the communication,computation and control technologies,Intelligent Transportation System(ITS)has been proposed as a promising solution to realize the secure,effective,reliable and green transportation system.Internet-ofVehicles(Io V)is composed with vehicles equipped with On-Board Units(OBU),cellular base stations,Roadside Units(RSU)and cloud-related devices.Combined with different types of components,Io V is an important part of ITS.In Io V,real-time and reliable information dissemination and sharing is the foundation to implement most of the relevant applications,which has aroused extensive attention and in-depth research from both academia and industry.With the latest research progress,this thesis studied three typical information dissemination scenarios in Io V including the vehicular beacon broadcast scheduling,multi-hop cooperative data delivery and roadside unit-assisted information dissemination,based on the characteristics of Io V,i.e.,resource sharing,cooperative dissemination and facility assistance.The main contributions of the thesis are summarized as follows.(1)This thesis has studied the vehicular beacon broadcasting scheduling in Io V.First,in order to properly allocate system resource,it designed a Software-Defined Vehicular Network architecture,which decoupling the data plane and control plane with specific vehicular communication technologies.Then,based on the proposed architecture,the vehicular beacon broadcasting scheduling problem considering the Age of Information(Ao I)is investigated.To mitigate the collision and improve the data dissemination performance,a low-complexity greedy algorithm minimizing the expected sum of Ao I was proposed for the broadcast scheduling.The proposed algorithm is proved to be optimal under the condition that the vehicles have the same number of neighbors and identical channel reliability which is likely held in the high-density scenario in reality.The simulation results reveal that the proposed solution outperforms the existing methods in terms of the efficiency,effectiveness and fairness.(2)This thesis has investigated the message delivery problem considering the bidirectional dissemination in hybrid V2I/V2 V networks.First,the capacity and delay during the message forward phase and message backward phase are modeled,respectively,so that the expected capacity and delay are accurately obtained based on the limited informationshared among vehicles.Based on the analysis,a multi-source message delivery strategy is proposed to reduce the expected delay,and the results also provide an important guideline on the RSU deployment density and coverage.The simulation results verify that the proposed solution can significantly reduce the delivery delay and the resource occupancy.(3)This thesis has investigated RSU task assignment and deployment with the delivery delay requirement for Io V.First,a novel utility function to evaluate the total benefits of the RSU deployment strategy is proposed.To obtain an effective solution,an optimization problem is formulated based on the utility function.Then,considering the irregular coverage area of each RSU,an LP-based clustering algorithm is designed to solve the problem.The proposed utility-based deployment algorithm(URDA)has a guaranteed performance according to the algorithm analysis.Additionally,the proposed URDA can adaptively adjust the strategy according to the deployment cost and is robust to the estimation errors.Based on the typical information dissemination scenarios including the beacon broadcast scheduling,multi-hop cooperative data delivery and roadside unit-assisted information dissemination in Io V,this thesis proposed the optimization methods to further improve the quality of service in the related applications,which laid a solid foundation for the implementation of the secure,efficient,and green ITS.