I. J. Computer Network and Information Security, 2012, 3, 8-16 Published Online April 2012 in MECS (http://www.mecs-press.org/) DOI: 10.5815/ijcnis.2012.03.02 Fast Vertical Handover Algorithm for Vehicular Communication: A Holistic Approach Sourav Dhar, Shubhajit Datta, Rabindra Nath Bera Department of E&C Engineering Sikkim Manipal Institute of Technology Majitar, Sikkim, INDIA- 737136 Email: sourav.dhar80@gmail.com Amitava Ray Department of Mechanical Engineering Sikkim Manipal Institute of Technology Majitar, Sikkim, INDIA- 737136 Abstract — Next generation vehicular communication environment will consist of heterogeneous radio access networks (RAN). For seamless connectivity, vertical handover is a mandatory requirement. A novel context aware vertical handover algorithm is presented here. TOPSIS (Technique for Order Preference by Similarity to Ideal Solution), which is a multi criteria decision making (MCDM) tool, is used for the development of algorithm and MATLAB/SIMULINK is used as simulation platform. The optimum network is selected, based on multiple factors such as network traffic load, velocity of mobile station, data rate, usage cost and initial delay of network, among the available networks such as WiMax, WLAN and UMTS. This algorithm has been tested by simulating a virtual road traffic scenario. Variations in optimum RAN selection with vehicle speed keeping network traffic load constant and RAN selection with network traffic load keeping vehicle speed constant are shown graphically. The proposed algorithm is very simple yet powerful compared to the existing VHO algorithms and hence requires less execution time. Index Terms — ITS, Vertical handover (VHO), MCDM, TOPSIS, V2V and V2I. I. INTRODUCTION The primary goal of Intelligent Transportation System (ITS) is to make journey safe and enjoyable by converging remote sensing, communication and information technologies with transportation engineering [1]. Intelligent Transportation Society of America (ITSA), which has collaboration with Association for Intelligent Transport System (AITS) INDIA, aims to improve cooperation among public and private sector organizations. ITSA summarizes its mission statement as “vision zero” meaning its goal is to reduce the fatal accidents and delays as much as possible [2]. Shladover [3] has given a review on recent research progress on highway vehicle automation and indicates the important research challenges that still need to be addressed before highway automation can become an everyday reality. The transportation problem is considered as a social problem in [4] and emphasis given on the fact that by the absence of the ITS people will suffer significant losses in terms of time, health, money and mobility. Implementation of sustainable transport is considered in [5]. Ubiquitous vehicle to vehicle (V2V) and vehicle to infrastructure (V2I) communications are essential for both safety and non safety applications of ITS. To maintain seamless connectivity, vertical handover (VHO) facility should be implemented in next generation communication devices. In homogeneous networks, horizontal handovers are typically required when the serving access router becomes unavailable due to mobile terminal’s movement. In heterogeneous RANs, the need for vertical handovers can be initiated for convenience rather than only connectivity reasons (e.g., according to user choice for a particular service). Implementation of “Always Best Connected (ABC)” concept, of being connected in the best possible way in an environment of heterogeneous RANs, is the major challenge in the design of VHO algorithms [6]. VHO decision problem in vehicular communication has been addressed in this paper. The VHO decision process answers when and where to hand over in a heterogeneous environment on the move. Decision criteria include Quality of Experience (QoE) parameters like user preferences as well as Quality of Service (QoS) parameters like network conditions, application requirements and terminal capabilities. These have to be evaluated and compared to detect and to trigger VHO. In the context of future wireless networks, many analysis, studies and tutorials were proposed in the literature [6-20], but none of these were proposed specific to a transport scenario. We show how advanced tools like TOPSIS (Technique for Order Preference by Similarity to Ideal Solution) as well as proven concepts can be used to solve such a problem and thus answering ABC requirement. Copyright © 2012 MECS I.J. Computer Network and Information Security, 2012, 3, 8-16