Design and Implementation of WLAN-Based Automatic Vehicle Identification

In this paper, we present a WLAN-based automatic vehicle identification (AVI) technique. AVI, typically used for electronic toll collection, is a basic functional requirement for a smart car. The development of this technique is a subtask of building a WLAN-based multi-purpose vehicular terminal device providing various functions, such as AVI, car-to-car communication and vehicular Internet access. The design and implementation of our WLAN-based AVI system was based on reducing the identification time in order to cover high-speed cars. As time is required to establish a network connection between a roadside access point and a car station, identifying a high-speed car by communicating through that network connection is not feasible. We utilize IEEE 802.11 management frame such as probe request frame in order to identify a station without establishing a network connection. We also control the timing of the scanning procedure in order to generate enough frames for reliable identification of high speed-cars. Based on the experimental results, our WLAN-based AVI system achieves an identification ratio of nearly 100% for various car speeds ranging from 40 km/h to 100 km/h, whereas, active RFID, one of the representative technologies for AVI, does not show reliable identification performance, especially at high-speeds.