Research On Routing Strategy Of Vehicle Ad Hoc Network For Urban Transportation

Vehicular Ad-hoc Networks(VANET)is an emerging technology that uses vehicles as network nodes for data transmission.It has important significance in improving road safety and promoting the development of urban intelligent transportation.In the urban traffic environment,this paper proposes two routing strategies under the IP network and Named Data Networking(NDN)to improve the performance of information routing.The main research contents are as follows:First,the existing geographic location-based vehicle-mounted ad hoc network routing strategy usually selects forwarding segments and forwarding vehicles in a locally optimal manner,lacking overall perception and feedback on the connection of vehicles on urban roads.When the traffic volume of urban roads changes,the routing path cannot be adjusted in time.In response to the above problems,a Greedy routing strategy of vehicular ad hoc network based on artificial bee colony is proposed.The strategy first models the problem of vehicle connectivity between the two intersections,abstracts the urban road as an undirected graph,and uses the reciprocal of the density of each road segment as the weight of the edge to obtain the initial routing path through the Dijkstra algorithm;Then,according to the process of finding the optimal solution according to the artificial bee colony algorithm,the feedback of the route of the source vehicle to the destination vehicle with the size of the fitness function as the target,so that the source vehicle dynamically selects the route of information routing;Finally,to multi-hop forwarding of information between vehicles adds a greedy forwarding mechanism with variable search range on the basis of a greedy routing strategy based on geographic location to improve the reliability of routing and reduce the probability of packet loss due to link disconnection.Simulation results show that the strategy reduces the end-to-end transmission delay of the data packet and improves the arrival rate of the data packet without a significant increase in routing overhead.Second,because traditional IP-based traditional networks transmit data end-to-end,IP addresses represent both identity and addresses,and are no longer applicable to highly dynamic networks such as VANET in terms of mobility.Therefore,this paper applies named data network to VANET and studies the broadcast routing strategy of VANET in NDN.Aiming at the problem that the delay-based VANET broadcast routing strategy in NDN has large end-to-end delays,the routing records are easily invalidated when sending back data packets,and the redundancy rate of data copies in the network is high,combined with the type of request messages in VANET due to the characteristics related to geographic location,a directional delayed routing strategy based on geographic location is proposed.The strategy first redesigned the hierarchical naming method of the content;secondly,it added some fields to the original NDN interest packets and data packets;and then added the beacon interest packets that obtained the location information to the delayed broadcast of the NDN,and proposed geo-based Location-oriented delayed broadcast mechanism;Finally,the characteristics of vehicles at intersections are analyzed,and a packet cache strategy based on intersections is proposed.The simulation results show that the proposed routing strategy has a higher interest packet hit rate and shorter average request latency than the default non-delayed broadcast routing strategy in NDN,the delay-based NDN-VANET broadcast routing strategy,and the ABC-VGRA routing strategy based on the IP network mentioned above.