The problem of information dissemination is researched for vehicular ad-hoc networks(VANET)inthis paper,and a contention-based efficient-information perception algorithm(CEiPA)is proposed.Theidea of CEiPA is that beacons are delivered over VANET with limited lifetime and efficient information.CEiPA consists of two phases.The first one is initialization phase,during which the count timers T_(cycle)and T_(local)are set to start beacon delivery while T_(cycle)is also used to monitor and restart beaconing.Thesecond one is beacon delivery phase.An elaborate distance function is employed to set contention delayfor beacons of each vehicle.In this way beacons will be sent in order,which decreases the collision ofbeacons.Simulation results show that CEiPA enables each beacon to carry more efficient information andspread them over more vehicles with lower network overhead than the periodic beacon scheme.CEiPA isalso flexible and scalable because the efficient information threshold it employs is a balance among thefreshness of information,network overhead and perception area of a vehicle.
