Research On Optimized Strategy Of Packet Scheduling In Self-powered Roadside Units For CVIS

As the core of the intelligent transportation system development,cooperative vehicle infrastructure system enables to realize the three aspects of pedestrian-vehicle-road dynamic real-time information exchange and collaboration,which improves the road capacity,operation efficiency of traffic,and ensure the safety,efficiency and environmental protection of the traffic system.In the cooperative vehicle infrastructure system,the roadside unit serves as the gateway node of the sensor network,completing the system environmental data monitoring and information servicing for passing vehicles,and forwarding the monitored information of traffic conditions,weather conditions,environmental data,and wildlife to the roadside unit connected to Internet and finally to the data centers by opportunistic “store-carry-forward”devices of passing vehicles,which is of great significance to improve the information services quality of the cooperative vehicle infrastructure system.In this paper,we mainly research the data packets transmission scheduling problem between roadside units and passing vehicles in the cooperative vehicle infrastructure system which is in the remote highway areas.Due to their deployment area conditions,roadside units in this scenario cannot access the Internet and power grid.These roadside units need to harvest renewable energy to realize self-powered function.For this application scenario,we solve the problem of minimizing the system packets average transmission delay under the constrains of energy factors.In this paper the research is mainly divided into following two aspects:(1)In order to solve the optimization problem of packet scheduling about vehiclesbetween self-powered roadside unit and Internet connected roadside unit,the packettransmission delay minimization problem is modeled under the application scenario and thesystem state transition and transmission delay is analyzed by Markov Decision ProcessFramework,and the strategy,packet scheduling scheme for energy-delay tradeoff inself-powered roadside units,is proposed.Finally,the strategy is compared with GreedyBundle Relaying Scheme and Q-learning by simulation experiment.The experiments verifythat the strategy can adaptively optimize packet scheduling under the constraints of theenergy,effectively reduce the system average packet transmission delay,and improve thesystem packets transmission efficiency.(2)Further expand the system application scenario,research the packet schedule of all the self-powered roadside units and passing vehicles in the system,a system optimization model is established by Lyapunov’s optimization theory,and the system states and decisionsare analyzed.In order to solve the optimization problem,the packet scheduling optimization model is transformed into a knapsack problem.An distributed packet scheduling scheme for energy-queue length tradeoff in the cooperative vehicle infrastructure system is proposed.Finally,the strategy is compared with Equal Allocation Strategy and Queue-weighted Strategy.The experiment results show that this strategy can effectively coordinate the relationship between energy consumption and packets queue length,and reduce the system packets transmission delay during the transmission process,improve the overall system efficiency,and upgrade the system data communication service quality.