Based On The Gis Information Subscription/release System Design And Implementation

With the development of wireless communication technologies,vehicle (VehicularAd hoc network,VANET) self-organizing network has gradually become an importantfield of wireless research.Today,VANET technologies,including Intelligent Transp-ortation (ITS),vehicle localizing,LBS (Location Based Service),and so on,can achieveaccident warning,driving assistance,traffic information query,and information ex-changing among vehicles or between passengers and vehicles,which rely on efficientpublish/subscribe (pub/sub) through vehicle-to-vehicle,vehicle-to-AP (Access Point)and Internet communication.In intelligent transportation,information transmission between vehicle nodes androadside facilities provides new solutions for transportation safety and efficiency. Indriving safety,vehicles in accidents or nearby roadside facilities can broadcast messagesto the rear of the directions of traffic,for avoiding more loss in high-speed highways. Inefficient transportation,vehicles not only directly exchange messages of local trafficstatus,but also could construct centralized systems,implement comprehensive analysisof regional information by central processing servers,respond real-time results to usersaccording to their subscriptions,and provide efficient,safe,and effective travel route foreach user.Since moving vehicles communicate with each other and roadside infrastructure inAd-hoc networks,they can collect data with basic equipment,integrate respectiveinformation,and construct pub/sub systems for distributing public messages,such asaccident warning mentioned above.In reality,road infrastructure cannot collect thestatus of each street corner.It is significant that single vehicles share information witheach other,avoiding independent islands of information.Thus,there is a huge potentialfor vehicular pub/sub systems in future urban construction and communicationsapplications.This thesis describes a GIS-based information pub/sub system under the platform ofvehicles,which involves how to construct a system for collecting subscription messages and distributing publish messages for users.After sorting out current messagedistribution mechanisms in vehicular networks,we propose a content-based messagedistribution solution,analyze the details of the algorithm,and discuss possible problemsin its implementation.At last,we simulate our scheme with real data of vehicularnetworks,achieve pub/sub among vehicles and between vehicles and infrastructure,andprove its good performance.