Systems coupling embedded computing and sensing have vast potential, particularly when wirelessly networked. However, the focus of much of the literature for wireless sensor network is on idealized systems with potentially millions of members (see for example), with minimal power, weight, and size. This focus on idealized systems can lead to discounting the use of current WLAN technologies such as 802.11, or WiFi, in sensor network applications. In this chapter we discuss the applicability of WiFi, as the preeminent WLAN technology, to wireless sensor network applications. We begin this discussion with an introduction to wireless sensor networks. Then we describe how the adhoc capabilities and communication efficiency of 802.11 radios are suited to certain sensor network applications. Finally, to illustrate a type of sensor network for which 802.11 radio properties are appropriate we provide an overview of a prototype wireless network for sonobuoys developed by Sensoria Corporation and Exponent Corporation, which was demonstrated using 802.11b radios.

Introduction

One application of ubiquitous computing is to create autonomous or semi-autonomous systems that monitor and report changes in the physical environment. When communicating wirelessly, this large range of systems is called wireless sensor networks. These networks are envisioned as large numbers of individual sensing “nodes”, each connected to its neighbors wirelessly, and networked together to enable communication, coordination, and collaboration. This interaction is envisioned between groups of nodes locally as well as across the network to entities potentially on external networks.