Research On Time-sensitive And Economical Mobile Cooperative Charging Scheduling Optimization For Sensor Devices

In recent years,the breakthrough of wireless power transfer technology has well solved the energy supply problem in wireless sensor networks,and makes the development of wireless rechargeable sensor networks be possible.Most of the existing work for wireless rechargeable sensor networks mainly consider the traditional charging network model,where the charging stations and sensor devices are all deployed and maintained by users.Unlike the existing work,this work proposes a novel cooperative charging service model.In this model,all charging stations are deployed and maintained by a Charging Service Provider(CSP).The user will periodically send a charging service request to CSP according to a specific charging requirement,and requires each sensor device in the network to move to the corresponding charging station to receive the charging service provided by CSP,and finally the user will pay CSP the corresponding charging service fee according to the charging service time.Based on the above-mentioned charging service model,this work mainly studies time-sensitive and economical mobile cooperative charging scheduling optimization problem,that is,how to find an optimal cooperative charging scheduling strategy for sensor devices to minimize the total charging service cost,subject to the constraints on out-of-service time.For this problem,this work makes an in-depth research for different types of application scenarios.(1)For the kind of delay-insensitive applications,this work investigates the location consistency based time-sensitive and economical mobile cooperative charging scheduling optimization problem for sensor devices.In this problem,each sensor device is assigned to a charging station under the constraint on out-of-service time,and returns to its initial deployment location after completion of charging.This work first proves the NP-hardness of this problem,then explores the problem with single charging station case,and proposes an optimal solution with polynomial time complexity.Based on the solution to the problem with single charging station case,this work further proposes an efficient approximation algorithm with polynomial time complexity for the problem with the case of multiple charging stations.Finally,the extensive simulation results show that the proposed algorithm in this work can reduce the total charging service cost by at least 20% compared with the other baseline solutions.(2)For the kind of delay-sensitive applications,this work investigates the topology consistency based time-sensitive and economical mobile cooperative charging scheduling optimization problem for sensor devices.This problem relaxes the constraints on the movement range of sensor devices,so that they do not have to return to the initial deployment positions after completion of charging,but only need to ensure that the topology formed by the returned deployment positions is consistent with the topology formed by the initial deployment positions.This work first studies the problem with single charging station case,which can be equivalently transformed into the maximum cardinality bottleneck bipartite graph matching problem by three times of optimization,and then designs an optimization algorithm with polynomial time complexity.Based on this solution,this work further proposes an efficient approximation algorithm with polynomial time complexity for the problem with the case of multiple charging stations.Finally,the extensive simulation results reveal that the proposed algorithm in this work greatly outperforms the other baseline solutions.