The performance of Wi-Fi and Zigbee networks for inter-vehicle communication in Bangkok metropolitan area

Many capital cities in the world encounter the similar problem of traffic jam due to the population growth and the need for transportation. Bangkok, Thailand is one of the top cities with serious traffic jam. An inter vehicle communication was proposed to provide the real time road information to realize the intelligent transportation system (ITS) with the hope to mitigate the serious traffic jam [1]. Several have proposed solutions for inter-vehicle communication using infrared (IR) Bluetooth, Wi-Fi and Wi-Max. In this paper we study the performance of Wi-Fi and Zigbee networks for inter-vehicle communication in Bangkok area using network simulation, ns-2. Our study is aimed to understand the effect of the number of installed road side stations to network performance. The study has shown that Wi-Fi network yields the higher successful rate and the shorter delay than that of Zigbee. From our results, the optimal number of installed road side stations in the case of WLAN is about 9 stations per sq. km. and this provides the successful transmission rate of 55%. In the case of using Zigbee networks, about 10 stations per sq. km. is needed with the condition that the vehicle density is at least 12 cars per sq. km. to provide the successful rate of 8%.