  Target localization and tracking problems in WSNs have received considerable
attention recently, driven by the requirement to achieve high localization
accuracy, with the minimum cost possible. In WSN based tracking applications,
it is critical to know the current location of any sensor node with the minimum
energy consumed. This paper focuses on the energy consumption issue in terms of
communication between nodes whenever the localization information is
transmitted to a sink node. Tracking through WSNs can be categorized into
centralized and decentralized systems. Decentralized systems offer low power
consumption when deployed to track a small number of mobile targets compared to
the centralized tracking systems. However, in several applications, it is
essential to position a large number of mobile targets. In such applications,
decentralized systems offer high power consumption, since the location of each
mobile target is required to be transmitted to a sink node, and this increases
the power consumption for the whole WSN. In this paper, we propose a power
efficient decentralized approach for tracking a large number of mobile targets
while offering reasonable localization accuracy through ZigBee network.
