Research Of Charging Strategy In Wireless Rechargeable Sensor Network Based On SDN

Wireless Sensor Network is composed of a large number of sensor nodes and one base station.It is mainly used to collect information related to the environment in which the nodes are located.It is an effective means for modern communication networks to obtain perceptual information.In recently years,WSN has been applied more and more widely.The sensor node carries limited energy and cannot be replenishment,leading to a short running time of WSN.The network energy problem has become a key problem restricting the development of WSNWith the development of science and technology,wireless energy transmission technology is proposed to store the external energy into the node battery through a specific energy conversion mode,which can effectively replenish the energy of WSN.This technology becomes the key to guarantee long-term running for WSN.At the same time Wireless Rechargeable Sensor Network(WRSN)concept was born.Using the Wireless Rechargeable Vehicle(WCV)for the node energy supplement successfully avoids the instability of the natural environment for energy.In order to ensure the long-term operation of the network,this paper studies the charging strategy of WCV in WRSN.Firstly,for large WRSN,in order to ensure that every node to be charged in the network can get timely energy supplement,the network needs to collect and monitor the location and energy information of the node instantly.This paper studies WRSN based on Software Defined Networking(SDN).The data layer and the control layer realize function decoupling.The network node is set in the SDN data layer,and the base station and WCV are set in the SDN control layer.At the same time,in view of the network delay problem caused by limitation of SDN controller management in WRSN,this paper puts forward Update-ByData-Traffic(UBDT)algorithm of SDN node.This algorithm shows that when the network data volume is larger,WRSN will upgrade some SDN sensor nodes to SDN controller.This algorithm can balance the task load of SDN controller,reduce the task of data forwarding of relay nodes,and ensure the effectiveness of network information.Secondly,the network node has the characteristic that when the energy is insufficient,the less the remaining energy is and the faster the energy demand increases.In order to evaluate the energy demand degree of nodes reasonably,Maslow's energy demand moment model is designed comprehensively based on the distance between nodes and WCV and the residual energy of nodes,and it is used as the measurement index of energy demand degree of nodes.Finally,based on the real-time monitoring of the information of each node in the network,this paper designs Instant On-Demand Charging Strategy(IOCS)for multi-WCVs.This algorithm can determine the charging sequence of WCV according to the Maslow's energy demand moment of each node in the network to be charged.In order to determine the number of WCV,this algorithm designs a charging service queue model,divides the charging service queue into multiple charging service sub-queues,and assigns a WCV to each queue.This algorithm also plans the driving route of WCV to realize the long-term operation of the network.In this paper,IOCS algorithm is compared with Nearest Job Next with Preemption(NJNP)and Ant Colony Optimization(ACO)algorithm by simulation.The simulation results show that the average corresponding time of the nodes,the average corresponding time of the nodes,the energy utilization rate of the network and the number of dead nodes obtained by IOCS algorithm are better than those of NJNP algorithm and ACO algorithm.With the continuous improvement of network technology,fully distributed and centerless network structure will be the development trend of WRSN in the future,and some functions in the base station can be transferred to distributed SDN controller.Therefore,the next step is to design a fully distributed management scheme of WRSN network and study the charging strategy in this environment.