25-08-2017, 09:32 PM
Introduction
A VANET consists of a set of vehicles equipped with a communication device, called on-board unit (OBU), and a set of stationary units along the roads, called road side units (RSUs). Each OBU has a radio interface to connect to other OBUs and RSUs, as well as wireless or wired interface to which an application unit can be attached. The main objectives of VANETs are to provide efficient vehicle-to-vehicle (V2V) and vehicle-to-RSU (V2R) communications.The inter-vehicle communication configuration uses multi-hop multicast/broadcast to transmit traffic related information over multiple hops to a group of receivers.In intelligent transportation systems, vehicles need only be concerned with activity on the road ahead and not behind . There are two types of message forwarding in inter-vehicle communications: naïve broadcasting and intelligent broadcasting. In naïve broadcasting, vehicles send broadcast messages periodically and at regular intervals.In Intelligent broadcasting the event-detecting vehicle receives the same message from behind, it assumes that at least one vehicle in the back has received it and ceases broadcasting.