Efficient On-Demand Multi-Node Charging Techniques for Wireless Sensor Networks
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Date
2016-10-01
Journal Title
Journal ISSN
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Publisher
Elsevier
Abstract
This paper deals with wireless charging in sensor networks and explores efficient policies to perform simultaneous
multi-node power transfer through a mobile charger (MC).The proposed solution, called On-demand Multi-node
Charging (OMC), features an original threshold-based tour launching (TTL) strategy, using request grouping, and a
path planning algorithm based on minimizing the number of stopping points in the charging tour. Contrary to existing
solutions, which focus on shortening the charging delays, OMC groups incoming charging requests and optimizes the
charging tour and the mobile charger energy consumption. Although slightly increasing the waiting time before nodes
are charged, this allows taking advantage of multiple simultaneous charges and also reduces node failures. At the
tour planning level, a new modeling approach is used. It leverages simultaneous energy transfer to multiple nodes by
maximizing the number of sensors that are charged at each stop. Given its NP-hardness, tour planning is approximated
through a clique partitioning problem, which is solved using a lightweight heuristic approach. The proposed schemes
are evaluated in offline and on-demand scenarios and compared against relevant state-of-the-art protocols. The results
in the offline scenario show that the path planning strategy reduces the number of stops and the energy consumed by
the mobile charger, compared to existing offline solutions. This is with further reduction in time complexity, due to the
simple heuristics that are used. The results in the on-demand scenario confirm the effectiveness of the path planning
strategy. More importantly, they show the impact of path planning, TTL and multi-node charging on the efficiency of
handling the requests, in a way that reduces node failures and the mobile charger energy expenditure.
Description
Keywords
Sensor networks, wireless energy transfer, mobile charger scheduling, magnetic resonance coupling