Study On Distribution Strategy And Consistency Policy Of Hovering Information In VANET

Among VANET (Vehicular Ad hoc Network), with the help of hovering information, we can hover and distribute some appropriate information in a specific area or a period of time, in order to reach the goal of sharing information, such as the distribution of road safety information and pushing of entertainment media information, etc. Not only can assist the driver to keep abreast of traffic out of horizon, and can help the driver grasp the surrounding commercial information broadly.High mobility of vehicles and change of road conditions can cause VANET unstable and unreliable, may result in uneven distribution in the hovering region, as well as information inconsistence on the node. How to distribute information efficiently and harmoniously and how to keep hovering information consistent on each node is a challenging problem. In this paper, we focus on discussion and research on distribution strategy and consistency policy of hovering information in VANET.(1) For distribution problem of hovering information in VANET, we use dynamic flooding strategy based on DPT (Distribution Path Tree). Firstly, we will divide hovering information in VANET into security and media to discussion. Then, we introduce the concept of LAT (Link Alive Time), and construct WDPT (Weighted Distribution Path Tree) with it. Meanwhile, depending on different distribution scenario of hovering information, we propose dynamic flooding distribution strategy based on the path tree and the table-drived distribution strategy based on the routing table. Finally, we conducted simulation experiments on ONE (Opportunistic Network Environment), to verify the feasibility and stability of our proposed distribution strategy. Experimental results show that these distribution strategy that we proposed have a obviously advantage on distribution requirements of hovering information in VANET.(2) For consistency problem of hovering information in VANET, we adopt consistency policy based on Paxos Protocol. Firstly, we use OSS (Order Store Stack) structure to store hovering information and routing information. Then we complete the process of decision and updating to hovering information based on Paxos Protocol, ultimately to achieve information consistency in the region. Meanwhile, in order to avoid live lock problems, we introduce leader election policy, and make the process of selection of RSU (Road Side Unit), optimizing the consistency strategies, so as to improve the stability of system. Finally, we use open source Paxos framework Zookeeper to simulate the decision and updating of consistency of hovering information in VANET, in order to verify the reliability and stability of our consistency strategy. Experimental results show that the consistency strategy we proposed can significantly ensure consistency and integrity of hovering information in VANET.