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Self-monitoring for sensor networks

Local monitoring is an effective mechanism for the security of wireless sensor networks (WSNs). Existing schemes assume the existence of sufficient number of active nodes to carry out monitoring operations. Such an assumption, however, is often difficult for a large scale sensor network. In this work, we focus on designing an efficient scheme integrated with good self-monitoring capability as well as providing an infrastructure for various security protocols using local monitoring. To the best of our knowledge, we are the first to present the formal study on finding optimized self-monitoring topology for WSNs. We show the problem is NP-complete even under the unit disk graph (UDG) model, and give the upper bound on the approximation ratio. We further propose two distributed polynomial algorithms with provable approximation ratio to address this issue. Through comprehensive simulations, we evaluate the effectiveness of this design.