Development of a cross-layered protocol stack for wireless sensor networks for mobile object tracking

Deploying and designing a system for object tracking in hostile, inaccessible environments is a challenging task. One of the ways of doing it is by using a global positioning system (GPS). However, systems based on GPS consume larger amount of power and may fail in covered regions. Moreover changing batteries frequently is also a problem. In this paper we have discussed the design and implementation of an energy-efficient cross-layered protocol stack for an application of wireless sensor networks aimed at tracking the co-ordinates of a mobile entity for habitat monitoring. We have implemented this on TelosB motes using TinyOS. This paper focuses on development of protocols pertaining to three layers of the stack viz. physical layer, MAC layer and application layer. The protocols implemented include variants of timing-sync protocol for sensor networks, weighted centroid localization and sensor medium access control (SMAC). Our SMAC variant forms the basic framework upon which the localization and time synchronization algorithms are implemented in the data period and synchronization period, respectively. The results of the designed protocols are significant and demonstrate the potential of the performance of the protocol stack.