Studies in rough set theory based routing protocols for vehicular ad hoc networks on freeways

Abstract

Vehicular Ad hoc NETworks (VANETs) are self-organizing ad hoc networks that are specifically designed for communication among vehicles. VANETs are a special case of Mobile Ad hoc NETworks (MANETs), where the mobile nodes are vehicles. There has not been much research in rural and freeway conditions. VANETs in such conditions can be characterized as partially connected, with low density and high node mobility. VANET applications can be broadly categorized into safety-related applications and comfort-related applications. Comfort-related applications include infotainment applications, which provide additional information or entertainment to the passenger and/or driver. This thesis focuses on comfort-related VANET applications. For this category of applications, a unicast routing protocol is required, to deliver relatively large data to a particular destination, in real time, over multi-hop paths. Rough Set Theory (RST) is a mathematical tool to deal with vagueness and uncertainty. Variable Precision Rough Sets (VPRS) is a generalized model of Rough Sets, aimed at modeling classification problems involving uncertain or imprecise information. In the work presented in this thesis, Rough Set based and Temporal Rough Set based routing protocols are studied in the sparse, highly mobile context of VANET routing on freeways. There is no earlier work in Rough Sets and VANETs. Four performance metrics Packet Delivery Ratio (PDR), Normalised Routing Load (NRL), Endto-End Delay (EED) and Average Hop Count (AHC) are used. The percentage improvement over the original Dynamic Source Routing (DSR) protocol is compared between the five different protocols. Temporal information does not appear to be that useful in VANETs on freeways, possibly due to the high mobility of the nodes. One of the Rough Set based routing protocols performed the best among the different protocols studied for VANETs in freeway scenarios. The PDR of all the five protocols is higher than that of DSR. newline newline newline