Cross-layer Routing Approach in High Speed Mobile Wireless Networks NURUL NAZIRAH M.I.M., ANIS IZZATI A.Z., NORSHEILA FISAL, SHARIFAH K. SYED YUSOF, SHARIFAH H.S. ARIFFIN, MAZLAN ABBAS UTM-MIMOS Center of Excellence Faculty of Electrical Engineering Universiti Teknologi Malaysia (UTM) UTM Skudai, 81310 Johor MALAYSIA nnazirah@fkegraduate.utm.my, anis_izzati86@yahoo.com, {sheila, kamilah, sharifah}@fke.utm.my, mazlan.abbas@mimos.my Abstract: - Vehicular networks are highly mobile wireless networks that can provide wide variety of services and applications such as public safety communications, crash avoidance, multimedia and Internet access in highways. Due to rapidly changing topology and high speed mobility of vehicles, designing routing algorithm in vehicular network is a challenging task. One of the critical issues of vehicular network are frequent path disruptions caused by high speed mobility of vehicle that leads to broken links which results in low throughput. This poses complex challenge in ensuring quality of service (QoS). A lot of research around the world is being conducted to define the standards for vehicular communication. In this paper, cross layer routing approach with optimization technique is proposed to overcome the challenge. The routing approach is expected to significantly improve QoS in vehicular networks. Key-Words: - Vehicular Network, Routing, Cross-layer, Multi-hop, Throughput, Delay 1 Introduction Vehicular network has the potential applications in providing support for Intelligent Transport System (ITS), multimedia and expediting the Internet access in highways [1]. Vehicular network consist on networks composed by vehicles equipped with wireless network devices which are able to spontaneously interconnect each other without the need for a permanent infrastructure [2]. Today, the technology for establishing vehicular network include the IEEE 802.11b (Wi-Fi), IEEE 802.11p and IEEE 802.16 (WiMAX). The main challenge and issue in vehicular network is designing routing algorithm in highly dynamic ad-hoc mode where the node is fast moving. The routing algorithm must adapt to the rapidly changing topology of fast moving vehicle. In vehicular network, finding the reliable path very much depends on network topology and traffic density. This poses a complex challenge in ensuring Quality of Service (QoS) in vehicular network. Traffic density has a large influence on road capacity and vehicle velocities. It often measured in the number of vehicles per unit distance. In low traffic densities, vehicles tend to move at faster rate but vehicles slow down as traffic density increases. Therefore, vehicular network poses many unique networking research challenges and the design of an efficient routing protocol for vehicular network is very crucial. In this paper, cross layer routing is proposed to overcome the challenge. The routing approach is expected to significantly improve QoS in vehicular networks. Moreover, the concept of relay techniques in IEEE 802.16j protocol is highlight to extend coverage area and supporting high speed mobility of vehicles. In this paper, a WiMAX multi-hop relay network is considered to increase the reliability and efficiency of vehicular networks. Table 1 exhibits the comparison of several routing protocols for vehicular networks. The remaining part of this paper is structured as follows: In Section 2, we take a look at the literature related to routing algorithm issues in wireless communication systems. Section 3 deals with a brief introduction of vehicular networks. Section 4 discusses a common relay concept in IEEE 802.16j. Section 5 describes the proposed work including system model and cross-layer routing approach. Finally, we conclude the paper in Section 6. Table 1: Comparison of Wireless Network Technologies [10]. Wireless Network ZigBee (802.15.4) WiFi (802.11b/g/n) WiMAX (802.16e/j) Data Rate 128 Kbps 11 Mbps 30 Mbps Range <150 m 100-300 m 3-5 Km Mobility LOW LOW HIGH SELECTED TOPICS in SYSTEM SCIENCE and SIMULATION in ENGINEERING ISSN: 1792-507X 238 ISBN: 978-960-474-230-1