An Optimal Setting for the Parameters of an Intelligent Flooding Scheme in VANETs

A number of Intelligent Flooding Schemes have been recently proposed in order to optimize message dissemination in Vehicular Ad Hoc Networks. In this paper we focus on a scheme which exploits a distributed timer-based contention mechanism for allowing only contention winners to forward the message and to suppress other potential forwarders. In particular, at each hop along the message propagation direction, potential forwarders wait for a time which is inversely proportional to their distance from the sender before rebroadcasting the packet; a potential forwarder is suppressed if it intercepts the packet rebroadcasted by another node during the waiting time. Performance of the scheme, in terms of message delivery ratio, delay and channel utilization, depends on the maximum waiting time (MaxWT) and on the maximum distance R allowed between the sender and a potential forwarder. This research work aims at evaluating an optimal setting of these parameters. We show that, although the values of MaxWT and R which maximize performance vary with traffic load and vehicle density, a dynamic algorithm is not essential. Then, we report how to set the values of the parameters to achieve a performance that is acceptable in the scenarios which we have considered.