ROC: Resilient online coverage for surveillance applications

We consider surveillance applications in which sensors are deployed in large numbers to improve coverage fidelity. Previous research has studied how to select active sensor covers (subsets of nodes that cover the field) to efficiently exploit redundant node deployment and tolerate unexpected node failures. Little attention was given to studying the tradeoff between fault tolerance and energy efficiency in sensor coverage. In this work, our objectives are twofold. First, we aim at rapidly restoring field coverage under unexpected sensor failures in an energy-efficient manner. Second, we want to flexibly support different degrees of redundancy in the field without needing centralized control. To meet these objectives, we propose design guidelines for applications that employ distributed cover-selection algorithms to control the degree of redundancy at local regions in the field. In addition, we develop a new distributed technique to facilitate switching between active covers without the need for node synchronization. Distributed cover selection protocols can be integrated into our referred to as resilient online coverage (ROC) framework. A key novelty in ROC is that it allows every sensor to control the degree of redundancy and surveillance in its region according to current network conditions. We analyze the benefits of ROC in terms of energy efficiency and fault tolerance. Through extensive simulations, we demonstrate the effectiveness of ROC in operational scenarios and compare its performance with previous surveillance techniques.