A timer-based Intelligent Flooding Scheme for VANETs

A number of Intelligent Flooding Schemes have been recently proposed to optimize message dissemination in Vehicular Ad Hoc Networks. Some of them exploit a distributed timer-based contention mechanism in order to allow the most suitable nodes to forward the packet and to suppress other potential forwarders. Unfortunately, due to some problems related to the suppression mechanism, most of these schemes are not able to completely avoid useless copies of the message to be broadcast. Moreover, in many cases, the contention mechanism determines when the message has to be rebroadcast, thus thwarting the application in processing the message. The use of MAC layer control packet handshake allows to mitigate the issues above, but it could lead to an unacceptable overhead and to a high probability of dissemination interruption. In this paper we propose a new scheme, called Data-Ack Scheme (DAS), which operates at MAC layer. It allows to reduce the overhead by using one only control packet and makes the dissemination interruption most unlikely. Simulation results have shown that in a typical vehicular scenario DAS performance is better than that obtained when either a MAC layer handshake-based scheme or a scheme which does not provide the use of control packets is adopted.