Mobile Charging Scheduling Optimization Method For Wireless Sensor Network

Traditional sensor nodes are equipped with batteries to maintain their work.Due to limited battery capacity,the life of the entire network is limited.Today,wireless charging technology can be used to extend network life.In this dissertation,the wireless charger is placed on the mobile car,combined into a mobile wireless charging vehicle,and schedule the mobile wireless charging vehicle to charge the nodes in the network.The wireless charging model can be divided into a single node model and a multi-node model,and the multi-node model can be divided into an omnidirectional wireless charging model and a directional wireless charging model according to its coverage.For the omnidirectional wireless charging model and the directional wireless charging model,a mobile scheduling optimization method is proposed respectively in this dissertation.The main research work of this dissertation is as follows:(1)Research the mobile charging scheduling optimization method based on omnidirectional wireless charging model,the optimization goal is to maximize network lifetime.Two problems are solved in this dissertation.The first problem is to determine the docking spots of the charging vehicle.The first problem is an NP-hard problem,and the second is to determine the charging time of the charging vehicle at each docking spot.In order to solve the above problems,this dissertation proposes two algorithms.The first is the docking spots selection algorithm,which first determines the stop area of the charging vehicle according to the coverage of the omnidirectional wireless charging model,and then determines the best docking spot in each stop area with the goal of maximizing the sum of the received power of the nodes.The second is a multiround scheduling algorithm.Based on the idea of binary search,the algorithm determines the maximum time that the charging car can stay at each stopping point,so that the node can receive the most energy and achieve the purpose of extending the network life as much as possible.(2)Research mobile charging scheduling optimization method based on directional wireless charging model for the first time,the optimization goal is to maximize the energy utilization of charging vehicle while maintaining sensor network working perpetually.In order to solve this optimization problem,this dissertation first proposes the definition of directional charging coverage utility,and converts the docking spots and direction selection of charging vehicle in a two-dimensional plane into a dual-objective optimization problem that minimizes the number of stops and maximizes the coverage utility.After proving that the optimization problem is an NPhard problem,an approximation algorithm is proposed.Then,the calculation method of the charging cycle is given,and it is proved that no node will exhaust the energy during the period.Then,through theoretical analysis,the scale of the network that a single directional charging vehicle can serve is given.Finally,the effectiveness of the algorithm is proved by simulations.