Research On Optimization Strategy Of Packet Scheduling In Roadside Units Of CVIS

Based on the intelligent intercommunication of vehicle to vehicle,vehicle to infrastructure and vehicle to pedestrian,cooperative vehicle infrastructure technology continuously penetrates and integrates wireless communication and Internet applications into the field of transportation.which has great significance to accelerate the informatization of transportation infrastructure and promote the development of intelligent transportation system.In the cooperative vehicle infrastructure system,the roadside unit(RSU),which is deployed along the highway,provides information service for the passing vehicles entering its coverage.The RSU can also transmit the collected information,including local traffic conditions,environmental monitoring,animal activities,and so on,to the other RSU through the passing vehicles,which serve as opportunistic store-carry-forward devices.The average end-to-end delay of packet transmission process between RSUs consists of two parts: average queueing delay at the buffer of the source RSU and average transmission delay caused by vehicles traveling from the source to the destination RSU.In this paper,we research on optimization strategy of packet scheduling in roadside units,and aim to minimize the average end-to-end delay in the process of packet transmission.Firstly,the system model was established for packet transmission between RSUs.Then,the state transition and delay performance of the system were analyzed by constrained Markov decision process framework,and a non-linear average end-to-end delay minimization problem was established and solved.Finally,the joint velocity and quene aware optimization strategy of packet scheduling,which is proposed in this paper,is compared with the existing greedy relay scheme and probability relay scheme in terms of delay performance.The tradeoff between the average queuing delay and the average transmission delay is verified by simulation.The simulation results show that the proposed optimization strategy of packet scheduling can effectively reduce the average end-to-end delay in the packet transmission process.