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

2.8 BACKBONES AND BROADCASTING IN SENSOR–ACTUATOR NETWORKS

Different from sensor networks or ad hoc networks, sensor actuator networks are normally heterogeneous networks where actuators are more powerful than sensors, in terms of the energy level, communication and computing capabilities and memory. Therefore, actuators are expected to take more responsibility and play more important roles in backbone construction and broadcasting. One existing solution described below uses access points instead of actuators, while the other is based on higher key assigned to actuators.

2.8.1 Broadcasting for Hybrid ad hoc and Sensor Networks

Routing and broadcasting for hybrid ad hoc and sensor networks was studied by Ingelrest et al. (2006a). It assumes that there are two types of nodes in the hybrid network: mobile nodes and fixed access points. The access points are more powerful than mobile nodes in terms of computational ability, memory, and energy supply. The mobiles can either directly connect to an access point, or use ad hoc mode to reach the access point via multiple hops. Figure 2.17 shows an example of such a hybrid network. There could be wired or wireless connection between access points P₁ and P₂. Mobile nodes a, b, c, f are directly connected to the access points while mobile nodes e and d require a relay of other mobile nodes to connect the access points.

Component neighbor elimination-based flooding was proposed in Ingelrest et al. (2006a). It divides the network into components, ...