for example, temperature, tools to support distributed signal processing, information humidity, or vibration-and requires advanced query storage and management, networking, and application interfaces and search engines to effectively support Communications Engineering Desk Reference; ISBN: 9780123746481 Copyright © 2004 Elsevier Inc. All rights reserved CHAPTER 3.7 Wireless sensor networks user-level functions. Sensor networks may internetwork energy consumption for communication and computa- with an IP core network via a number of gateways, as in tion is in the range of 1000 to 10,000. Despite the Figure 3.7-1. A gateway routes user queries or commands advances in silicon fabrication technologies, wireless to appropriate nodes in a sensor network. It also routes communication will continue to dominate the energy sensor data, at times aggregated and summarized, to consumption of networked embedded systems for the users who have requested it or are expected to utilize the foreseeable future. information. A data repository or storage service may be Thus, minimizing the amount and range of commu- present at the gateway, in addition to data logging at each nication as much as possible-for example, through local sensor. collaboration among sensors, duplicate data suppression, The repository may serve as an intermediary be- or invoking only the nodes that are relevant to a given tween users and sensors, providing a persistent data task-can significantly prolong the life of a sensor net- storage. Additionally, one or more data storage devices work and leave nodes free to support multiuser opera- may be attached to the IP network, to archive sensor tions. In addition, the shorter RF transmission range data from a number of edge sensor networks and to improves spectrum usage and increases throughput for support a variety of user-initiated browsing and search a sensor network. functions. The information management and networking for The current generation of wireless sensor hardware this new network will require more than 