Research Of Efficient And Security Urban Vehicle Routing In VANETs

With the rapid development of the city,the number of vehicles shows an exponential growth,which brings great convenience to people but also incurs a huge burden on urban traffic.To address the negative problem caused by the rapid growth of the number of the vehicles,many vehicle scheduling methods have been proposed to plan the vehicles' driving path scientifically.However,the navigation algorithm used in the existing vehicle scheduling methods mostly focus on how to using the historical driving data to predict the future driving status.With the large-scale popularization of vehicle navigation equipment,the path-seeking process has a greater impact on future driving conditions than other factors.Thus,the existing urban vehicle routing method is difficult to adapt to the future environment.To solve this problem,the paper carries a series of researches on the vehicle routing method for urban environment combined with the VANET technology.The main contents of this paper include the following aspects:1)Travel time evaluation method in urban environment with routing information sharingThe interaction between vehicles and vehicles in the path-seeking process gradually replaced the static factors,such as road width and lanes number,and it has become the main factor to determine the road patency.Based on the analysis of the general driving rules of urban vehicles,this paper studies the mutual influence of vehicles in driving process.Utilizing the vehicle navigation devices and the intelligent devices widely used in people's cars,the paper proposes a vehicle travel time evaluation method with routing information sharing.By taking into account the interaction of vehicles,the traffic signal control lights and other extensive transport infrastructure under the urban environment,the proposed method can provide a more accurate travel time evaluation for each vehicle.By taking into account the interaction of vehicles,the traffic signal control lights and other extensive transport infrastructure under the urban environment,the proposed method can provide a more accurate travel time evaluation for each vehicle.2)The urban vehicle routing method for the VENET environmentBased on the vehicle travel time evaluation method with routing information sharing,this paper further studies the vehicle routing algorithm and proposes a vehicle routing algorithm aimed at minimizing overall travel time of vehicles.By collecting and analyzing the travel planning information of the on-line vehicles,and combining the travel time evaluation method based on routing information sharing,the algorithm can fully considers the mutual impact of the vehicle routing behaviors on the traffic status,and it can also reduce the negative impact of routing behaviors on other vehicles.Compare to the existing methods,this algorithm can decrease the retarded vehicles on road by 18%to 30%and thus significantly reduce the urban road congestion level.3)The emergency message broadcast method for handling traffic incidentIn the process of vehicle routing,it is possible for vehicles to encounter the traffic congestions,traffic accidents or other traffic incidents.By broadcasting an emergency message,vehicles can inform the vehicles that can be affected potentially,so that they can take actions to avoid or reduce the negative impact of these traffic incidents in advance.In order to cover the most of potential affected vehicles,the emergency messages needs to be broadcasted far enough.Thus,the broadcast needs to be relayed by several vehicles.Most existing emergency message broadcasting method ignore the factor of the distribution of the optimal node position so that it cannot adapt well to the distribution of the optimal forwarding node.Therefore,in order to further improve the timeliness of emergency message broadcasting and reduce the propagation delay,the paper proposes a like-Huffman coding-based emergency message broadcasting method.Our simulation results show that the proposed method can reduce the delay of emergency message broadcasts in different scenarios,improve the speed of emergency message transmission and improve the response efficiency of traffic incidents in the routing process of urban vehicles.4)Information security and privacy protection of the routing systemSince the urban vehicle routing method with internet of vehicles depends on the travel planning information shared by other vehicles,the security of the sharing information must be ensured.At the same time,the involved vehicle travel information and other personal information also need to be properly protected.In this paper,an improved session initialization protocol is proposed to solve the above problems in the information sharing process.Our improved protocol can provide greater security and provide privacy-preserving function.Meanwhile,the improved protocol can reduce the computation overhead,especially the computation overhead at the side of server,which makes it more suitable for the large-scale vehicle routing process.