International Journal on New Computer Architectures and Their Applications (IJNCAA) 1(3): 542- 552 The Society of Digital Information and Wireless Communications, 2011 (ISSN: 2220-9085) 542 QoS Measurement of Single-hop Periodic Communication in Vehicular Environment Bilal Munir Mughal 1 , Asif Ali Wagan 2 , Halabi Hasbullah 3 Department of Computer and Information Sciences, Universiti Teknologi PETRONAS, Bandar Seri Iskandar, 31750 Tronoh, Perak, Malaysia 1 bilalmunirmughal@gmail.com, 2 asifwaggan@gmail.com, 3 halabi@petronas.com.my ABSTRACT Life safety on road is the key motivation behind the research in Vehicular Ad-hoc Network (VANET). As basic communication mechanism VANET- equipped vehicles broadcast periodic safety beacons to keep the neighboring vehicles aware of the situation at all times. Well known broadcast communication problems i.e. hidden/exposed nodes, collisions and inherent challenges in VANET e.g. dynamic environment, limited bandwidth, are prone to hinder the exchange of potentially lifesaving information. Furthermore, the most of vehicle-to-vehicle broadcast communication will comprise of single-hop periodic safety beacons thus it becomes important to measure their Quality of Service (QoS) under congested vehicular environment. With the help of extensive simulations, a detailed analysis is presented to assess the performance of single-hop periodic safety beacons. Parameters i.e. communication range, beacon generation interval and safety beacon size are effective in controlling the QoS levels. The QoS metrics used for the evaluation are packet delivery ratio, per-node throughput, end-to- end delay and Packet loss ratio breakup. Simulation results show that in congested environment it is very difficult to meet the safety application‟s QoS requirements. KEYWORDS VANET; safety beacons; single-hop; PDR; PLR 1 INTRODUCTION Vehicular ad-hoc network (VANET) is essentially a part of Intelligent Transportation System (ITS) and inherits some of its technological background from Mobile Ad-hoc Network (MANET). Primarily VANET applications are designed to human life safety however many applications not related to safety are also envisioned e.g. toll collection, internet etc. All the information exchange between vehicles takes place via periodic or event-driven messaging. Providing efficient safety messaging scheme is a challenging task due to some specific characteristics of VANET i.e. high mobility, limited channel bandwidth, very short communication duration, and highly dynamic topology. Furthermore the broadcast nature of communication in VANET, may lead to saturated/congested channel. Being basic safety communication mechanism, single-hop periodic safety beacons (SBs) will predominantly occupy the control channel communication and may easily consume entire available bandwidth. Most of the previous research work is focused on multi-hop communication.