Actor Repositioning in Wireless Sensor and Actor Networks

Abstract

In Wireless Sensor and Actor Networks (WSANs), the phenomena`s of sensing and acting are performed by sensor and actor nodes, respectively. The number of sensor nodes deployed in a target area may be in the order of hundreds or thousands. Actor nodes are generally few in number because actors have higher capabilities and can act on larger area. In WSANs, actors are responsible for taking a localized decision which may require strong co-ordination with neighboring actors. One of the major problems in WSANs is to place the actors within the monitored region so that certain goals, such as maximizing actor coverage, minimizing data collection delay, balancing the acting load etc., can be achieved. However it may not be possible in many applications as sensor networks are deployed on a fly. As a result precise deployment is difficult at network establishment time. Upon the occurrence of an event the nodes report the event to their nearby actor which can be at a substantial hop distance from event region. In order to decrease the energy consumption of nodes and to increase the network lifetime actors can be repositioned near to event region. In existing literature, very little work has been done in the field of actor placement/ positioning in WSANs. This work has been focused on the development of an Efficient Actor Repositioning (EAR) algorithm that is aimed to extend the network life time by reducing the energy consumption of the network. An actor using EAR algorithm can find the appropriate co-ordinates to reposition/ relocate itself or some other actor based on Euclidean distance, energy of the region and number of nodes.