Physical Layer Aspects of Information Exchange in the NOTICE Architecture

Recently, Yan et al. [1] introduced NOTICE, a scalable, secure and privacy-aware architecture for the notification of traffic-related incidents, such as congestion and other similar events. NOTICE uses belts of piezo-electric elements embedded in the highways to detect variations in the characteristics of traffic flow. NOTICE uses very short-range wireless communications between vehicles and belts. In turn, these very short-range communications impose constraints on the time available for connection establishment and data exchange. While understanding the physical layer requirements for communication is key to a successful implementation of NOTICE, these requirements were not specifically addressed in [1]. The main goal of this work is to investigate physical layer requirements for successful communication in the NOTICE architecture. Our main contribution is to study the probabilities of establishing the wireless link and of successfully exchanging information between a belt and a vehicle passing over it. We derive analytical expressions for these probabilities as functions of several parameters such as the time available for handshaking/information exchange, average speed of the vehicle, data rate and amount of information to be exchanged between the vehicle and belt, and we evaluate their values for specific parameters corresponding to practical scenarios. Our results indicate that inexpensive short-range ZigBee radios, when combined with probabilistic data collection, are good candidates for the physical layer of NOTICE.