Research On Mobile Charging Vehicle Scheduling Algorithm In Wireless Rechargeable Sensor Network

Wireless Sensor Networks have a wide range of applications in the fields of transportation,environmental monitoring,industrial manufacturing,medical and health,anti-terrorism and disaster preventing,national defense and military.Because the battery capacity of sensor nodes in WSN is limited and difficult to replace,this restricts the popularization and application of WSN.The breakthrough progress of wireless energy transfer technology laid the foundation for solving the energy supply problem of nodes in WSN,and made the wireless rechargeable sensor network emerge as the times require.The charging vehicle moves back and forth in the network coverage area,and uses WPT technology to charge it when it is close to the target node.However,the energy carried by the charging vehicle is also limited,and the energy consumption rate of each node in the network is quite different.How to effectively schedule the charging car so that it can charge as many nodes as possible in a service cycle and reduce the number of dead nodes,is a core issue of concern in WRSN.In WRSN,the research work of the existing charging vehicle scheduling problem is mainly carried out around the situation that there is only one charging vehicle in the network.In such a scenario,the initial position of the charging vehicle is near the central base station.When the charging service starts,the charging vehicle leaves the base station and heads to the destination node to charge.When the energy of the charging vehicle is insufficient,it returns to the base station to replenish energy.However,when the network scale is large and the nodes are dense,a single charging vehicle often cannot serve the nodes with charging needs within a service cycle,resulting in the death of the nodes.At this time,it is necessary to add multiple charging vehicles to the network to replenish energy for the nodes.In order to ensure the maximization of the survival rate of sensor nodes in WRSN and maximize the energy using efficiency of charging vehicles,under the multi-charging vehicle charging model,this paper conducts an in-depth study on the scheduling problem of multiple charging vehicles in WRSN.The main research content as follows:(1)In WRSN,considering that the node close to the base station needs to be a relay node to forward data to other nodes,its energy consumption rate is relatively large.In addition,nodes in different regions often have different energy consumption rates during their work.If setting the same energy alarm threshold for all nodes in the network,it is easy to cause those nodes with high energy consumption rate to fail to be charged in time.Therefore,in order to be able to provide service for those nodes that are really in urgent need of charging,this paper performs non-uniform clustering according to the distance between sensor nodes and base station,and sets the energy alarm threshold of each node in the cluster according to the energy consumption rate of sensor nodes.The setting of an energy alarm threshold greatly shortens the repetitive cycle of the charging car and improves the energy use efficiency of the charging car.(2)In order to obtain the high survival rate of sensor nodes in WRSN and the high energy using efficiency of charging vehicles,under the multi-charging vehicles charging model,this paper proposes an Efficient Ene Rgy algorithm based on Hybrid Scheduling(E~2RHS).The E~2RHS algorithm consists of two sub-algorithms of shortest charging path planning and path optimization.The base station first models the path planning problem of the charging vehicle as a conditionally restricted TSP problem.After receiving the charging request sent by sensor nodes,calling the SOM algorithm to construct a shortest charging path for the charging vehicle.However,the shortest charging path calculated by the above algorithm cannot guarantee the survival rate of sensor nodes,so the shortest charging path needs to be further optimized.Based on this,a path optimization algorithm is proposed.The algorithm adjusts the charging sequence of nodes by comparing the maximum tolerable delay time and the shortest waiting time of each node in the shortest charging path,and optimizes the charging path of the charging vehicle,thereby ensuring survival rate of nodes in the network.(3)Aiming at the problem of cooperative charging scheduling of multiple charging vehicles in WRSN,this paper proposes a Collaborative Efficient Ene Rgy algorithm based on Hybrid Scheduling(C-E~2RHS)for cooperative charging of charging vehicles.The charging car collaboration algorithm based on logical partition"aggregates"the nodes that need to assist in charging and the nodes that need to assist in the charging of the charging vahicle,and uses the K-Means algorithm to logically partition.Each assisting charging car is responsible for the charging task of a node in a logical area,solving the problem of assisting in the selection of charging vehicles and the allocation of charging tasks;in order to ensure the survival rate of sensor nodes after logical partitioning,calling the charging path planning algorithm to plan an optimal charging path for the charging vehicles.