As with many technologies, defense applications have been a driver for research in sensor networks, which started around 1980 due to two important programs of the Defense Advanced Research Projects Agency (DARPA): the distributed sensor networks (DSN) and the sensor information technology (SensIT) (Chong & Kumar, 2003). However, the development of sensor networks requires advances in several areas: sensing, communication, and computing. The explosive growth of the personal communications market has driven the cost of radio devices down and has increased the quality. At the same time, technological advances in wireless communications and electronic devices (such as low-cost, low-power, small, simple yet efficient wireless communication equipment) have enabled the manufacturing of sensor nodes and, consequently, the development of wireless sensor networks (WSNs).
Key Terms in this Chapter
Sensor Node (or Mote): A basic unit in a sensor network, with on-board sensors, processor, memory, wireless modem, and power supply.
Network Topology: A connectivity graph where nodes are sensor nodes and edges are communication links (one-hop connection).
In-Network: A style of processing in which the data is processed and combined near where data is generated.
Data Centric: Approaches that routes or access a piece of data via its properties (such as physical location).
Sensor: A transducer that converts a physical phenomenon (light, temperature, motion, etc.) into an electrical signal.
Sink Node: Special nodes where data collected (sometimes, already aggregated data) is sent.
Collaborative Processing: Sensors cooperatively processing data from multiple sources in order to serve a high-level task.