Optimization of actors placement in WSANs based on imposed delay constraints

Wireless Sensor and Actor Networks (WSANs) refer to a group of sensors and actors linked by wireless medium to probe environment and perform specific actions. These actions should be taken before an established deadline when an event of interest is detected. According to the relationship between the end-to-end delay and the number of hops for sensed data passing through, the size of the WSANs cluster should be limited. In this paper, we find a method to determine the maximum size of the WSANs cluster which enables the cluster-head to receive data and take actions in an imposed time-delay. For clustering of the WSANs, a k-MTE clustering algorithm is proposed which is inspired by the regular six-polygon deployment. In this algorithm, actors are employed as cluster-heads and placed in such a way that sensors could route data to actors within k hops. The maximum size of k-MTE based cluster is determined by statistical analysis of simulation experiments and thus the number of actors needed to cover a certain area can be determinate. At last, we evaluate the placement of actors and the results show that our approach is effective.