Distributed and collaborative node mobility management for dynamic coverage improvement in hybrid sensor networks

Abstract

With recent advances in deploying sensor nodes mounted on mobile platforms, node mobility is becoming an attractive alternative to improve network coverage dynamically in sensor networks. However, due to energy constraints, it may not be cost effective to deploy a large number of mobile nodes for continuous movements. It might be more desirable to allow only a certain number of nodes to be mobile depending on the affordable cost and desired performance levels. This paper proposes an efficient distributed mobility protocol for mobile node navigation in a hybrid sensor network consisting of both static and mobile nodes to provide efficient time-varying coverage after the initial deployment. In the proposed scheme, mobile nodes collaborate with neighboring static nodes to find their candidate locations to move at each movement step in order to maximize the coverage time of the area not covered by static nodes. We also develop an efficient sequential algorithm to find the exposure in a hybrid network, which reflects the best path for a target to traverse the sensing region without being detected. By simulations, we show the effectiveness of the proposed mobility protocol in terms of the presence probability matrix and coverage time and show its suitability at the worst-case target exposure. © 2011 Thakshila Wimalajeewa and Sudharman K. Jayaweera.