Safety message dissemination in VANETs: Flooding or trajectory-based?

In this paper, we address the reliable alarm message dissemination in Vehicular Ad hoc NETworks (VANETs) environment. We study various techniques to disseminate emergency data, after a car crash, within a group of vehicles. We consider a trajectory-based data dissemination technique to perform broadcast flooding task optimization, and compare it with a pure flooding scheme. For the evaluation, we examine various parameters such as inter-vehicle distance, transmission radio range and traffic load. Experimental results, obtained by several simulations implemented on VanetMobiSim/NS-2 platform, show the effectiveness of trajectory-based solutions for efficient dissemination of emergency messages in VANETs. We also conclude that a simple flooding technique is not always considered harmful, and can outperform more complicated schemes in high density VANETs environment.