A Mobile Charging Strategy Based On Cost Minimization For Energy Hole Mitigation In Wireless Rechargeable Sensor Networks

For traditional Wireless Sensor Networks(WSN),the limitation of nodes’ energy storage makes the network prone to the phenomenon of "energy hole",which affects the network’s performance.To solve this problem,most scholars have studied the technology of energy saving,energy harvesting and wireless recharging.With The introduction of wireless recharging technology,Wireless Rechargeable Sensor Network(WRSN)has become a reality,and the phenomenon of "energy hole" has been well alleviated.In order to reduce the failure rate of nodes and the WCVs’ moving cost,this thesis designs a data uploading strategy of energy balance,and then the network is divided into several regions according to this strategy.Finally,a reasonable trajectory is built for WCV in each region,which effectively alleviated the phenomenon of "energy hole".Firstly,a data uploading model with energy balance is designed.Based on the minimum spanning tree,an initial data uploading sub-tree is constructed considering both of the hop count and the remaining lifetime of nodes.In addition,considering the influence of distance between nodes on energy consumption on data transmission,the tree is further adjusted,and finally the energy balanced data uploading tree is built.Secondly,the network is divided into several regions and each of them is assigned a WCV.By searching for "shadow nodes",the most suitable traversal position of each WCV is obtained that maximizes the charging benefit.It not only saves some chocking nodes,but also reduces the WCVs’ moving cost and charging delay.Finally,for nodes that are still chocked,this thesis further proposes a strategy of "partial charging" for their pre-sequence nodes,which shortens their waiting time to be charged,and reduces the failure rate of nodes to a certain extent.Simulation results show that the proposed data uploading strategy can prolong the remaining lifetime of nodes by about 10.41% and the network lifetime by nearly 10.78%,which considers the influences of hop count,the remaining lifetime of nodes and the distance between nodes on route construction.Compared with MERSH and NJNP,the proposed mobile charging strategy reduces the node failure rate by 5% and 10% respectively,and the moving cost of WCV is reduced by about12% and 17% as well.