Wireless Sensor and Actuator Networks: Algorithms and Protocols for Scalable Coordination and Data Communication

1.9 ARCHITECTURES FOR WIRELESS SENSOR AND ACTUATOR NETWORKS

Although WSNs have been employed in many applications, such as environment monitoring and health care, there are an increasing number of applications that require the use of actuators along with sensors. This occurs when the network system needs to interact with the physical system or the environment via actuators (also called actors). From the engineering aspect, an actuator is a transducer that accepts a signal and converts it to a physical action. Actuators transform an input signal into an action upon the environment. Typical examples of actuators are robots, electrical motors, and humans. Traditional sensor and actuator networks use wired communications among themselves; these networks have been well studied. The advent of small, intelligent, low-energy, and low-cost wireless sensing and actuation devices has the potential to significantly expand existing applications of wired sensor actuator networks. Wireless sensor actuator networks (WSANs) are emerging as the next generation of WSNs. The major difference between WSANs and WSNs is that WSANs are capable of changing the environment and physical world while WSNs cannot. Wireless sensor actuator networks are envisioned for applications that include disaster relief operations, intelligent buildings, home automation, smart spaces, pervasive computing systems, cyber-physical systems and nuclear, biological, and chemical attack detection (Xia et al., 2007).

A WSAN usually ...