A Hybrid Adaptive Dissemination Solution Based on Geographic Distance for Vehicular Ad Hoc Networks

Increasing amount of vehicles are being equipped with embedded sensors, processing and wireless communication capabilities. This has opened a myriad of possibilities for varying applications on safety, public collaboration and participation. Message dissemination is one of the many fundamental services in Vehicular Ad hoc Networks (VANETs). For this purpose, in this paper we describe HADD, a hybrid adaptive dissemination protocol based on geographic distance. Contrary to other existing approaches that focus exclusively on always-connected networks, it is designed to operate under any kind of road traffic condition. We propose a new geographic-based broadcast suppression strategy to broadcast the message waiting in the local buffer queue to other vehicles. Finally, HADD employs a rate control scheme that sets the pace at which messages must be transmitted according to the perceived network data traffic, thus avoiding channel overloading. Hence, HADD adapts not only to the varying road traffic condition, but also to the perceived wireless channel quality. When compared to two related and well-accepted protocols under Manhattan grid scenarios, we show that, overall, HADD is more reliable and efficient in terms of message delivery.