Research On Hierarchical VANET Routing Protocol Based On RSU And Named Data Network

Vehicle Ad-hoc Network(VANET)is the core foundation for building Intelligent Transportation System,and it carries functions such as vehicle communication,traffic data collection and traffic data distribution.With the development and application of computing technology and communication technology,VANET continues to advance to intelligent and networked.Nowadays,how to reduce data transmission delay,improve data delivery rate and data service quality has suggested as the pivotal issue in VANET.This thesis focuses on the deployment problem of RSU nodes in VANET and the routing problem between vehicle nodes,it is indispensible to analyze the existing RSU usage scheme and routing protocol.In this study,non-overlapping RSU coverage division method and adaptive data update control scheme,and efficient routing protocol was designed to improve data service quality,reduce data transmission delay and improve routing efficiency.The main research content of this thesis is summarized as follows:(1)Non-overlapping RSU coverage division and adaptive data update control.First,RSU coverage range division method based on link connectivity probability.In order to solve the overlapping problem of coverage area in the process of deploying RSU,the probability statistical method is used to establish the connection probability calculation model of the road segment.Then we use the model to calculate connection probability of each road segment based on the traffic data collected by SUMO.The watershed algorithm is used to design the RSU coverage division method based on link connectivity probability,the method is used to realize the RSU non-overlapping coverage division,and theoretically analyzed to verify the feasibility of the method.Second,RSU adaptive data update control scheme based on fuzzy logic.In order to solve the problem of communication resource waste and data failure caused by different RSU updating data in the same period,using fuzzy logic idea,the data DS and data update rate URD in RSU vehicle information registry are extracted as fuzzy input,the data updating period T is used as the decision-making system output.The degree membership function corresponding to the fuzzy input is calculated by the expert experience method,and the fuzzy control rules are designed by using the IF-THEN principle.Finally,the decision output is defuzzified by the maximum membership method.The RSU adaptively controls the data update cycle,and the proposed scheme is evaluated and analyzed using the BUS-VANET routing protocol framework to verify the effectiveness of the proposed scheme.(2)Hierarchical VANET routing protocol for RSU communication unit based on named data networking(NDN).Aiming at the problems of low routing efficiency,unstable communication path and high delay of data transmission in VANET routing protocols at present,a hierarchical VANET routing protocol for RSU communication unit based on NDN is proposed named NR-VANET.NR-VANET divides large-scale VANET into logical communication area based on RSU communication unit,and constructs hierarchical network structure based on logical communication area.RSU makes use of wired or wireless network connection as the backbone network layer of RSU.The ordinary nodes in VANET constitute the ordinary vehicle layer.The communication between vehicle nodes in NR-VANET is limited in the communication unit,and the data interaction between the communication units is carried out through RSU.The data transmission between nodes is based on the data content-centered NDN network.NACK packets are added to the NDN for route recovery,and the link-state domain is added to the forwarding information table to select the link-state optimal forwarding path to forward the data.Compared with MMM-VNDN routing protocol,NR-VANET routing protocol has higher data delivery rate,lower data transmission delay and better quality of service.