Using Utility and Microutility for Information Dissemination in Vehicle Ad Hoc Networks

We describe an approach to propagating streams of information in Vehicle Ad-Hoc Networks (VANETs) based on sources of information anticipating where their information will be useful. In this paper we describe how sources can model the potential usefulness of their information using utility functions. These utility functions are converted to more compact "microutilities" that travel with the individual data packets. The microutilities allow the information forwarding protocols to operate distributedly and independently on individual data packets, while achieving good overall coordination and delivery for entire data streams. We describe the algorithms used to convert utility functions to microutilities. Our algorithms insure that both proactive planning and reactive dropping of information in-transit are done consistent with the needs of the different applications. In this way data streams from both high priority (safety) and lower priority (traffic and commercial) applications can be propagated in the same network. We show experimental results that demonstrate the advantage of such a utility-microutility approach in serving the needs of diverse intelligent transportation system applications.