Research On Traffic Information Sharing System Based On NDN In VANET

With the continuous development of the automobile and transportation industry,the increase in vehicle holdings and traffic risks are accompanied by more and more traffic accidents in people's view,and the sharing of traffic information between vehicles is particularly important.However,the traffic information sharing system in the VANET network based on the TCP/IP architecture has the problems of centralized communication,poor disaster tolerance of single service nodes and delay of information response.The main reason for these problems is that the IP network architecture establishes the end-to-end connected communication.In mobile network,NDN has a natural support for mobility.A car only need to ask for data again,when it leaves original place,it could get data from new places around it without keeping connection with the original data source and reestablishing the connection.NDN is a future content-centric network architecture,which uses named data instead of existing IP address and applies a new packet encapsulation structure and routing addressing mode to reform the IP routing strategy.What's more,NDN adopts in-network cache mechanism,using data converting buffer to improve the efficiency of retrieving data.NDN mechanism with no center,no level is more suitable to support the structure of the VANET network.The goal of this paper is to propose a traffic information sharing system based on NDN mechanism in VANET network without using central server.In this system,every vehicle node can play as publisher,consumer and forwarder.Vehicles can undertake the forwarding of a message and cache through the NDN mechanism,and make the driver query traffic information by other vehicles fast and efficiently without the conventional central server.In this paper,a new PFAC(Part Forward and All Cache)algorithm is proposed based on the NDN original forwarding strategy,naming strategy and caching strategy.It is designed to control the dissemination distance of traffic information and make the data more valuable in the range,and select the better node as the next hop-forwarding node considering the density factor to avoid excessive occupation of channels and conflicts.At the same time,more nodes cache data to reduce the response delay time and improve the success rate of requests.Based on the NDN forwarding strategy PFAC algorithm,which is adapted to VANET,this paper uses the ndnSIM based on NS-3 as the NDN simulation tool for simulation experiments to evaluate the performance of the proposed.The experimental results show that the PFAC strategy can effectively reduce the delay time for packet response,which will improve the success rate of requests and cache hit rate.Although it takes up a lot of storage space,but it is acceptable due to the strong storage capacity of the VANET network.