Data communication continues to expand in both scope and complexity, from internal communication among the hardware components of an individual computer to intercomputer network communication via wired or wireless BANs, PANs, LANs, MANs, and WANs. At the same time, computers are becoming more closely related to the physical world and human beings, gathering, monitoring, processing, and analyzing data to allow instrumentation and automation and to facilitate decision-making. Wireless sensor networks (WSNs) represent networks that are embedded into our physical environments. A sensor is a tiny electronic device that can respond to a physical stimulus and convert it into numeric data. A WSN is composed of many low-power, low-cost, autonomous sensor nodes interconnected with wireless communication of sensory data. A myriad of measurements can be done by sensors, including environmental properties such as temperatures, humidity, and air pressure; presence, vibration, and motion detection of objects; chemical properties; radiation levels; GPS; light; and acoustic and seismic activities. Data gathering is conducted intermittently at a specified frequency. A sensor node in a WSN possesses sufficient computing power to process sensory data gathered locally or transmitted from other sensor nodes via wireless links. Furthermore, sensor nodes in a WSN self-organize into a network topology, thereby improving robustness and reducing maintenance costs.
Source of Information : Elsevier Wireless Networking Complete 2010