Optimal k-Coverage Charging Problem
Wireless rechargeable sensor networks, consisting of sensor nodes with rechargeable batteries and mobile chargers to replenish their batteries, have gradually become a promising solution to the bottleneck of energy limitation that hinders the wide deployment of wireless sensor networks (WSN). In this paper, we focus on the mobile charger scheduling and path optimization scenario in which the k-coverage ability of a network system needs to be maintained. We formulate the optimal k-coverage charging problem of finding a feasible path for a mobile charger to charge a set of sensor nodes within their estimated charging time windows under the constraint of maintaining the k-coverage ability of the network system, with an objective of minimizing the energy consumption on traveling per tour. We show the hardness of the problem that even finding a feasible path for the trivial case of the problem is an NP-complete one with no polytime constant-factor approximation algorithm.
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