Research On Adaptive Routing Protocol In Vehicular Delay Tolerant Networks

In the Vehicular Ad-hoc NETworks(VANETs),intermittent connections and link interruption happen frequently.But Vehicular Delay Tolerant Networks(VDTN)allows vehicle nodes to carry data information and forward them opportunistically in the process of moving.This mechanism effectively alleviates the problems of interruption through data transmission and large delivery delay.However,the existing Delay Tolerant Networks(DTN)routing algorithms are not suitable in VDTN like the urban traffic environment.Therefore,constructing a routing algorithm for VDTN environment is of practical significance.Meanwhile,an appropriate routing algorithm will be helpful in developing applications for transportation service.Based on analyzing the characteristics of VANETs and the architecture of DTN,some classic algorithms used in DTN environment are analyzed.Combining the environmental characteristics of urban roads,this paper integrates multivariate impact factor from the perspective of the historical transmission behavior among vehicle nodes,message type,realtime road condition information,etc.Finally,an Adaptive Routing Framework in VDTN environment(ARFV)is proposed in this paper,in which the message is divided into early warning messages and auxiliary service messages.Corresponding routing algorithms are also designed for different types of messages.For the early warning message,a Routing Algorithm based on Discrete Interaction(RADI)is proposed.This algorithm evaluates the degree of discrete interaction of nodes from many aspects and estimates the delivery delay based on location information.Correspondingly,for the auxiliary service messages,a Routing Algorithm based on Dynamic Traffic Flow(RADTF)is proposed.Firstly the speed-density model is designed to calculate and identify the traffic density of the current road segment.When the density falls into low value interval,unconditional broadcast strategy will be adopted.However,if the density falls into the interval from medium to high,the concepts of motion tropism and interactive reachability are introduced,and the real-time traffic density is also integrated into the routing and forwarding strategy.Because the routing algorithms designed in this paper considers the node historical communication behavior and evaluates it,the algorithms have certain anti-aggression.The VDTN environment is built on the simulation platform which is called Opportunistic Network Environment(ONE).The two routing algorithms under the framework of this paper are simulated and compared with two classic routing algorithms Epidemic and Prophet in this environment too.The simulation results show that compared with the classic routing algorithms,the two routing algorithms proposed in this paper effectively improve the efficiency of data transmission in the VDTN.At the same time,they have certain anti-attack performance against common black hole attacks.