《15_Enabling Localization Services in Single and Multihop Wireless Networks》.pdf

CHAPTER 15 ENABLING LOCALIZATION SERVICES IN SINGLE AND MULTIHOP WIRELESS NETWORKS VASILEIOS LAKAFOSIS, RUSHI VYAS, and MANOS M. TENTZERIS Department of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, Georgia, USA 15.1 INTRODUCTION Localization is the process of determining the physical positions of devices with a specific degree of accuracy in indoor or outdoor environments. The physical location of a user, device, or mote within an area covered by a wireless network can prove to be a very useful or even indispensable functionality in many applications. First of all, high correlation between data captured—for instance, environmental— and locality may be required for the data to be meaningful. Device tracking, involving location and bearing, is another type of application that makes use of different localization techniques. Location awareness is also the basic component of a special category of routing protocols, namely, geographic aware ones, where the traffic is relayed to or from a particular area of the sensing field. Finally, context-aware applications can make smarter decisions in terms of user interface or behavior when knowledge of the physical location of the nodes is available. This chapter reviews the most representative and reliable localization techniques, most of which can be easily deployed in existing networks, as well as presents how these have been expanded to provide localization solutions suitable for environments where mostly multihop connectivity can be established with anchor nodes; nodes whose exact location coordinates are known a priori. It should be noted that most of these techniques are based on methods used since ancient and medieval times by Thales from Miletus, Claudius Ptolemaus, Leon Battista Alberti, and others [1] and are still used mostly in navigation systems. Handbook of Smart Antennas for RFID Systems, Edited by Nemai Chandra Karmakar Cop