Wireless sensor and actor networks : research challenges q Ian F . Akyildiz , Ismail

Wireless sensor and actor networks (WSANs) refer to a group of sensors and actors linked by wireless medium to perform distributed sensing and acting tasks. In such a network, sensors gather information about the physical world, while actors take decisions and then perform appropriate actions upon the environment, which allows a user to effectively sense and act at a distance. In order to provide effective sensing and acting, a distributed local coordination mechanism is required among sensors and actors. Moreover, so as to perform right and timely actions, sensor data must be valid at the time of acting. Thus, one of the main goals in WSANs is to decrease the communication delay between sensing and acting. This paper describes these coordination and communication problems in WSANs. General differences between wireless sensor networks (WSNs) and WSANs are explored, and the physical architecture of WSANs is outlined. Furthermore, sensor–actor and actor–actor coordination problems are discussed and research challenges and requirements in communication protocols occurring due to the presence of actors are explored. 2004 Elsevier B.V. All rights reserved.