Research On Event Monitoring-oriented Mobile Charging Scheduling In Wireless Sensor Networks

Wireless sensor network is an important branch of the Internet of Things,and is widely used in environmental monitoring,smart homes,smart agriculture,intelligent transportation,and other fields.However,the sensors have limited energy capacity and short lifetimes,and often require periodic battery replacement,which result in expensive maintenance cost and great inconvenience.It is a key issue to prolong the lifetime of sensors in wireless sensor networks.With the development of wireless charging technology,wireless rechargeable sensor networks have become a promising solution for extending network lifespan.In order to prolong the lifetime of wireless sensor networks and improve the monitoring quality of wireless sensor networks,this thesis closely links event monitoring and wireless charging,and studies the event monitoring-oriented charging scheduling problem.Firstly,this thesis studies the scheduling of multiple mobile chargers in a point-to-point charging scenario with the goal of maximizing charging utility.We formalize the problem as an event monitoring-oriented multi-charger scheduling problem and prove that this problem is NP-hard.Then,we propose a event monitoring-oriented charging scheduling algorithm(ECSA)using a combination of greedy algorithms and submodular function maximization method to solve this problem,and prove the approximate ratio of the algorithm.Finally,the effectiveness of the algorithm is verified through extensive simulation experiments,and the results show that ECSA can significantly improve charging utility,which is increased by up to 13.2% on average compared with the comparative algorithms.By properly adjusting the coil frequencies of mobile chargers and sensors,multiple-node charging can be achieved to effectively improve charging performance.This thesis further extends the event monitoring-oriented multi-charger scheduling problem and introduces the partial charging mechanism,and the event monitoring-oriented multi-node partial charging scheduling problem is studied.This introduce proposes a multi-node partial charging scheduling algorithm(MPCSA)to solve this problem and provides an analysis of the algorithm’s properties.Finally,the effectiveness and superiority of this algorithm are further verified through simulation experiments.The simulation results show that the MPCSA algorithm is superior to other comparative algorithms in terms of charging utility and dead sensor count.The charging utility is increased by up to 50.4% on average compared with the comparison algorithm,and the number of death sensor nodes is reduced by 66.7%.