Assessment of signal propagation in vehicular communications for dynamic data collection systems

Abstract

The use of intelligent transport systems has a positive impact on the environment. As vehicle move in an optimized manner and travellers are advised to use the most suitable transport means to reach their intended destination, the travel times and congestions decrease, the fuel consumption also decrease and the emissions are reduced. The key element is to have knowledge about the transport system in order to be able to process and distribute the information to all the traffic participants. A wide-spread data collection system may provide information that, through integration in other Intelligent Transport Systems (ITS), will be able to provide an added value. Dynamic data collection systems, that imply information gathering along a route and data delivery in specific points (or continuously along the path) rely on communications that must ensure a proper handshake time and data rate to allow for all the relevant data to be sent. In different environments (city, highway etc.) where different speeds of vehicles have various influences on signal propagation, an initial evaluation of Doppler shifts of signal frequency depending on speed is important to reveal the probability for the receiver to be able to capture the modified signal. In this paper Doppler shifts tests have been performed for different speeds (inside and outside cities, highways) and conclusions are presented at the end.