An Information Lookup Mechanism Based On Two-tier Clustring Structure

Vehicular Ad hoc Network (VANET) is a kind of Mobile Ad hoc networks which formed by communication between vehicles, vehicles and road side infrastructures by using wireless communication technologies. It can provide diverse services for urban road traffic safety assurance and traffic management, and bring great convenience to people's travelling. However, the mobility of the vehicle leads to dynamic changing of topology and worse information transmission quality, which bring great challenges to inter-vehicle information lookup and reliable transmission. Therefore, how to improve transmission quality between vehicles and lookup efficiency of the network has become a key issue in VANET. To address these problems, this paper carries out research in two aspects: to improve information transmission reliability between vehicles and reduce information redundancy of the network.Firstly, the architecture and characteristics of VANET are briefly introduced, and then the current research hotspots are discussed.Secondly, aiming at the dynamically changing topology and the poor transmission quality, the VANET/P2P structure with high information transmission reliability is adopted in VANET. Besides, the distance between nodes, mobility and other factors are considered in designing the weight-based local QoS assurance clustering algorithm. Through this algorithm, a topology maintenance strategy in dynamic scenario is given.The simulation results show that the proposed clustering algorithm has better information transmission quality, higher cluster structure stability and lower clustering and maintenance overhead.Furthermore, to reduce information redundancy of traditional information lookup mechanisms in VANET/P2P structure networks, an information lookup mechanism based on reachable probability is proposed. The reachable probability model is used to obtain the probability of reaching lookup messages' destination, and to determine the forwarding range of lookup message. The simulation results show that the proposed mechanism can effectively reduce lookup latency and overhead at a high lookup success rate.By using the mechanism proposed in this paper, the reliability of information transmission can be improved, and the information lookup overhead can be reduced. As the result, the quality of information transmission between vehicles and the lookup efficiency are improved as well.