Robust Sensor Placements at Informative and Communication-efficient Locations
CARNEGIE-MELLON UNIV PITTSBURGH PA SCHOOL OF COMPUTER SCIENCE
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When monitoring spatial phenomena with wireless sensor networks, selecting the best sensor placements is a fundamental task. Not only should the sensors be informative, but they should also be able to communicate efficiently. In this paper we present a data-driven approach that addresses the three central aspects of this problem measuring the predictive quality of a set of hypothetical sensor locations, predicting the communication cost involved with these placements and designing an algorithm with provable quality guarantees that optimizes the NP-hard tradeoff. Specifically, we use data from a pilot deployment to build non-parametric probabilistic models called Gaussian Processes GPs both for the spatial phenomena of interest and for the spatial variability of link qualities, which allows us to estimate predictive power and communication cost of unsensed locations. Surprisingly, uncertainty in the representation of link qualities plays an important role in estimating communication costs. Using these models, we present a novel, polynomial-time data-driven algorithm, PSPIEL, which selects Sensor Placements at Informative and communication-Efficient Locations. Our approach exploit two important properties of this problem submodularity, formalizing the intuition that adding a node to a small deployment can help more than adding it to a large deployment and locality, under which nodes that are far from each other provide almost independent information. Exploiting these properties, we prove strong approximation guarantees for our approach. We also show how our placements can be made robust against changes in the environment and how PSPIEL can be used to plan informative paths for exploration using mobile robots. We provide extensive experimental validation of this practical approach on several real-world placement problems, and built a complete system implementation on 46 Tmote Sky Motes, demonstrating significant advantages over existing methods.
- Radio Communications