Coordination Protocols of Multiple Actuator Nodes in a Multi-Actuator/Multi-Sensor Model

In a wireless sensor and actuator network (WSAN), a group of sensor, actuator, and actuation device nodes are interconnected in wireless networks. Sensor nodes send sensed values of an event to actuator nodes. Messages may be lost due to collision and noise and nodes may be faulty. Here, actuator nodes have to perform appropriate actions on actuation devices on receipt of sensed values from sensor nodes in presence of node and network faults. In the multi-actuator/multi-sensor (MAMS) model, each sensor node sends sensed values to multiple actuators and each actuator node receives sensed values from multiple sensor nodes. Even if messages are lost and some number of sensor and actuator nodes are faulty, actuator nodes can surely receive sensed values required to make a decision. In this paper, we discuss how multiple actuator nodes cooperate to receive sensed values and perform actions on actuation devices. We discuss active, semi-active, passive, and semi-passive coordination protocols for multiple actuators. We evaluate the semi-passive coordination protocol in terms of the number of messages exchanged among actuators.