Research On Charging Strategy For Large-Scale Wireless Rechargeable Sensor Networks

Wireless Rechargeable Sensor Network(WRSN)introduces Wireless Power Transfer(WPT)technology on the basis of Wireless Sensor Networks(WSN).With low power consumption,low cost and multi-functional features,it is widely used in modern industry,environmental monitoring,human health management and transportation management.In the application of WRSN,WPT technology needs to cooperate with charging strategy for network energy replenishment,and a reasonable charging strategy can effectively solve the problem of network energy limitation,so as to ensure the stable operation of the network.At present,the charging strategy problem has become the core problem that WRSN applications urgently need to solve.Compared with small-scale WRSNs,the energy demand of large-scale WRSNs is larger,and the energy consumption rate of Sensor Node(SN)is more dynamic and varied,which leads to a more prominent energy-constrained problem of large-scale WRSNs.Therefore,in order to solve the energy constrained problem of large-scale WRSNs,this paper proposes a static partitioning plus dynamic cooperative charging strategy MMCCS(Multiple Mobile Chargers Cooperative Charging Strategy)for WRSNs with the minimum energy hole rate as the goal.The main work and contributions of this paper are as follows:(1)A dual partition of the wireless rechargeable sensor network is established.Firstly,the network model and energy consumption model of WRSN are built,and the model assumptions and performance evaluation indexes are defined for WRSN.Secondly,the number of Mobile Charger(MC)that guarantees the normal operation of the network is solved by calculating the energy consumption and replenishment of the network as a whole.Then,the improved K-means algorithm is used to cluster the sensor nodes with high similarity in physical distance and energy consumption rate,so as to divide the WRSN charging service partition.Finally,the WRSN is divided into concentric circle threshold partitions,and different charging request thresholds are established for different threshold partitions based on individual node survival rate and network node survival rate.The dual partitioning of the wireless rechargeable sensor network divides the charging service partition and the charging request threshold partition of the WRSN,which can reduce the SN charging waiting time and shorten the MC charging service distance,and carry out to ensure the timely replenishment of the network energy.(2)A multi-MC collaborative charging path planning algorithm is proposed based on the dual partitioning of WRSN.Firstly,the charging fitness between sensor nodes and mobile chargers is introduced,and the charging fitness is used to judge the cooperative capability and the cooperative task division of multi-MC.Then,the charging priority of the sensor nodes to be charged is proposed based on the objective of the minimum energy hole rate of WRSN,and this is used to guide the charging path planning of MCs.Finally,an improved ant colony algorithm is used for MC regression path planning to make full use of the remaining energy of the mobile charger.The multi-MC cooperative charging path planning algorithm consists of MC charging path planning algorithm and MC regression path algorithm,which can significantly reduce the WRSN energy hole rate and extend the WRSN survival cycle,thus ensuring the stable operation of the network.Simulation results show that the MMCCS strategy can reduce SN charging waiting time,shorten MC charging service distance and reduce WRSN energy hole rate compared with NJNP strategy,HC strategy and TSCCS strategy.