tailieunhanh - Wireless Sentor Network

Wireless sensor nodes are small, embedded computing devices that interface with sensors/ actuators and communicate using short-range wireless transmitters. Such nodes act autonomously, but cooperatively to form a logical network, in which data packets are routed hop-by-hop towards management nodes, typically called sinks or base stations. A Wireless Sensor Network (WSN) comprises of a potentially large set of nodes that may be distributed over a wide geographical area, indoor or outdoor | WIRELESS SENSOR NETWORKS TECHNOLOGY ANO APPLICATIONS idud tv MoMmmjd A. Mato itfTtCK Chapter 1 Efficient Node Placement for Congestion Control in Wireless Sensor Networks Charalambos Sergiou and Vasos Vassiliou Additional information is available at the end of the chapter http 48201 1. Introduction Wireless sensor nodes are small embedded computing devices that interface with sensors actuators and communicate using short-range wireless transmitters. Such nodes act autonomously but cooperatively to form a logical network in which data packets are routed hop-by-hop towards management nodes typically called sinks or base stations. A Wireless Sensor Network WSN comprises of a potentially large set of nodes that may be distributed over a wide geographical area indoor or outdoor. Wireless Sensor Networks WSNs enable numerous sensing and monitoring services in areas of vital importance such as efficient industry production safety and security at home as well as in traffic and environmental monitoring. Traffic patterns in WSNs can be derived from the physical processes that they sense. WSNs typically operate under light load and suddenly become active in response to a detected or monitored event. Early research studies in WSNs targeted military applications especially for battlefield monitoring. In the last few years due to the progress of low powered units and improvements in radio technologies wireless sensor networks technologies have gained momentum. WSNs are now being deployed in civilian areas and being used for habitat observation 1 2 health monitoring 3 object tracking 4 5 etc. In addition lately there is an emergence of mission-critical applications 6 . Emergence of mission-critical and information demanding applications in WSNs renders performance control essential for mission accomplishment. Heavy traffic load is a major factor that affects the performance of any type of network. The situation worsens in low-powered unreliable WSNs. Thus a .