Research On Charging Exclusivity Problem For Wireless Rechargeable Sensor Networks

As an epoch-making technology,wireless power transfer provides an effective and reliable solution for the energy supply of sensor nodes in wireless rechargeable sensor networks(WRSNs),and brings more possibilities for the application of WRSNs in more extensive fields.The design and optimization of the charging scheduling algorithm in the network has gradually become a research hotspot.Existing charging scheduling methods mainly concentrate on performance improvement theoretically,neglecting the fact that most Commercial-Off-The-Shelf(COTS)rechargeable sensors(e.g.,WISP and Powercast)are not allowed to conduct sensing and energy harvesting tasks simultaneously,termed charging exclusivity.Therefore,their schemes are not feasible for some practical applications.In this paper,we focus on the charging exclusivity issue in stochastic events monitoring while improving network performance.While optimizing the charging utility,we try to avoid the loss of monitoring utility caused by charging exclusivity.Specifically,we coordinate the charging behavior of the mobile charger and the sensing behavior of sensor nodes to formalize the charging exclusive optimization problem and further model it as a combinatorial optimization problem.We introduce novel discretization techniques and investigate the routing problem to reformulate the original problem into the maximization of a submodular function.The output of our proposed algorithm is better than(1-?)(1-1/e)/2 of the optimal solution to the original problem with a smaller charging radius(1-?)Dc.Through extensive simulations,numerical results show that in terms of charging utility,our algorithm outperforms baseline algorithms by 19.7%on average.Moreover,we conduct test-bed experiments to demonstrate the feasibility of our scheme in real scenarios.