| Limited energy is one of the most critical factors that hindering the deployment of wireless sensor networks. The emergence of wireless energy transfer technology based on magnetic resonant coupling makes it possible for mobile charging vehicles to provide controllable and perpetual energy for wireless sensor networks. Therefore, how to design effective mobile charging schemes to ensure the continuous operation of the networks has become a hot research topic.This thesis studies the charging strategy of single mobile charger firstly. The majority of charging schemes all assume that charging requests in near future are given in advance, the energy capacity of mobile charger is unlimited, and the charging order is only determined by the single factor. Therefore, an online on-demand charging scheme is proposed in this paper which takes the residual lifetime and the location of sensors into consideration. Meanwhile, the maximum network lifetime charging scheduling(MNLCS) strategy with limited working time for mobile charger has been put forward. The proposed strategy can effectively improve the network lifetime and lower the maintenance cost.Considering the diversity and variation characteristics of node energy consumption, two charging schemes based on clustering are presented in this thesis. One is a fixed maximum charging cycle charging scheme and the other one is a variable maximum charging cycle charging scheme. Furthermore, three charging cooperation modes for chargers are designed in this paper, including Nearest Request Priority(NRP), Workload Balance Dispatch(WBD) and Partition Charging Scheme(PCS).Finally, the simulation results show that the MNLCS algorithm not only significantly improve the network lifetime and charging efficiency, but also reduce charging delay in single mobile charger scenario. In multiple mobile chargers model, the service cost in NRP charging cooperation mode is lower than WBD and PCS, no matter the maximum charging cycle is fixed or not. |
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