Distributed algorithm for the actor coverage problem in WSN-based precision irrigation applications

In this paper, we study the actor coverage problem with the goal of meeting the requirements of precision irrigation applications in Wireless sensor and Actor Networks (WSANs), which are: (1) the volume of water applied by actors should match plant water demand and (2) minimizing over-irrigation to the largest extent. We take a novel approach to define and resolve the actor coverage problem. Based on this approach, we propose two algorithms: Centralized Actor-Coverage-IRRIG (CACI) and Distributed Actor-Coverage-IRRIG (DACI). The existing centralized and distributed approaches for the minimum cost actor coverage problem in WSANs are not optimal for all metrics. The communication scheme of DACI is designed in the way that it can keep the advantages of the centralized and the distributed approaches without inheriting their weaknesses. DACI constructs an actor cover set with the same optimality cost as CACI while incurring low signaling overhead. Complexity analysis and simulations results show that CACI and DACI are both better than the existing centralized algorithm in terms of cover set optimality. DACI has the same communication cost as the existing distributed algorithm with lower event-to-action delay.