Probabilistic relay selection in timer-based dissemination protocols for VANETs

Abstract

Implementations of data dissemination protocols in Vehicular Ad-Hoc Networks (VANETs) typically use multi-hopping approaches at the network layer, employing timers whose expiration times determine whether a vehicle should relay a message. These protocols, when they interact with lower access layers, such as the IEEE 802.11p MAC, are often affected by phenomena that impair the performance of the dissemination process. In this paper, we highlight the spurious forwarding phenomenon that arises when using timer-based protocols. We demonstrate the degradation incurred in the packet dissemination performance when the VANET is loaded by a high rate of packet flows. We then propose a probabilistic decimation approach, demonstrate its ability to alleviate the spurious forwarding problem, and discuss its performance as a function of vehicular traffic density and packet flow rate. Comparisons with other probabilistic dissemination protocols highlight the significant performance improvement attained by using our approach, assuring the realization of high throughput rate and packet delivery ratio.