 and Systems for Video Video (NOSSDAV), Zushi, Japan, Distortion Optimization for Video Technology, vol. 6, no. 1, pp. 1-11, July 1996. Streaming Using Packet February 1996. [60] H. Liu and M. El Zarki. Interleaving," in Proceedings of the [58] B. Dempsey, J. Liebeherr, and A. "Performance of H.263 Video 36th Asilomar Conference on Signals, Weaver. "On Retransmission-Based Transmission over Wireless Channels Systems and Computers, Pacific Error Control for Continuous Media Using Hybrid ARQ," IEEE Journal on Grove, CA, November 2002. Traffic in Packet-Switching Selected Areas in Communications, [56] S.B. Wicker. Error Control Systems Networks," Computer Networks and vol. 15, no. 9, pp. 1775-1786, for Digital Communication and ISDN Systems Journal, vol. 28, no. 5, December 1999. Storage, Prentice Hall, 1995. pp. 719-736, March 1996. This page intentionally left blank Chapter 3.7 Wireless sensor networks Feng Zhao and Leonidas Guibas The most profound technologies are those that development. While this book will primarily focus on disappear. They weave themselves into the fabric of wireless sensor networks, some of the principles, such as everyday life until they are indistinguishable from it. those of collaborative information processing and man- -The late Mark Weiser, Father of Ubiquitous Computing and agement, apply equally well to wireline sensor networks. Chief Technologist of Xerox PARC The issues of scalability and efficient use of bandwidth, a main concern of the book, are common to both wireless Advances in wireless networking, micro-fabrication and and wireline sensor networks. integration (for example, sensors and actuators manufactured using micro-electromechanical system technology, or MEMS), and embedded microprocessors have enabled a new generation of massive-scale sensor 3.7.1 Unique constraints and networks suitable for a range of commercial and military challenges applications. The technology promises to revolutionize the way we live, work, and interact with the physical Unlike a centralized system