Research On Information Forwarding Strategy In Vehicle Ad Hoc Network

The Vehicular Ad Hoc Network is a special wireless Mobile Ad Hoc Network composed of mobile vehicle nodes,which is an important application scenario in the future 5G communication.Compared with the traditional Mobile Ad Hoc Network,Vehicular Ad Hoc Network has the characteristics of fast network topology change and high-speed movement of vehicle nodes.So that the channel access protocol and information forwarding strategy in the traditional Mobile Ad Hoc Network are not applicable.The information forwarding strategy in Vehicular Ad Hoc Network is a hot research topic currently.This thesis mainly studies the information strategy of vehicles in Vehicle Ad Hoc Network.For the channel access problem of different vehicles' requests in Vehicular Ad Hoc Network,a fairness-based multi-channel MAC access algorithm is proposed based on the Medium Access Control layer multi-channel access protocol in Vehicular Ad Hoc Network.Firstly,the back-off algorithm is improved.Vehicles in the network need to adjust the size of their back-off window to determine the back-off time of access channel according to the traffic volume they have sent and the average value of the vehicles around them.Then,the vehicles use the current vehicle density in the network to adjust the durations of different periods.The simulation results show that the proposed algorithm can effectively improve the fairness of each vehicle's in the network and improve the network throughput.For the forwarding strategy of vehicle request information in Vehicular Ad Hoc Network,a forwarding strategy based on content relationship degree and retention time is proposed.Firstly,the content relationship degree is calculated using the content record table maintained by each vehicle and the retention time is defined considering the distance between vehicles,the speed and other factors.Combining the content relationship degree with the retention time,the vehicles can select the most suitable forwarding nodes.Then,in the return process of content information,the content caching strategy is added.The simulation results show that the proposed forwarding strategy can effectively improve the success rate of vehicle requests,reduce the path length of successful requests,and reduce the request delay.For the forwarding strategy of the content information of vehicles in Vehicle Ad Hoc Network,a content forwarding node selection strategy based on the types of service is proposed combining with the advantages of Named Data Networking.First,the vehicles in Vehicular Ad Hoc Network calculate the bandwidth occupancy factor according to the bandwidth occupancy table of maintained by the neighbor vehicles,the bandwidth required and the occupancy time of the transmitting content;then,the virtual arrival time is calculated according to the distance between the vehicles,the speed and the driving direction.Combining with the bandwidth occupancy,the appropriate forwarding node is selected.Finally,the forwarding node decides whether to participate in forwarding according to its own bandwidth occupancy,so as to ensure the quality of service of different service types and the success of the forwarding node selection.The simulation results show that the proposed content forwarding node selection strategy can effectively improve the successful arrival rate of content data packets,reduce transmission delay and improve network performance on the basis of meeting the bandwidth requirements for different service types.