Radio Frequency Energy Source Path Planning And Data Collection For Wireless Rechargeable Sensor Network

In the traditional Wireless Sensor Networks(WSN),energy consumption is an important problem that must be faced.To this end,Wireless Rechargeable Sensor Networks(WRSN)has been born.In this network,the Radio Frequency(RF)energy source sends the electric energy to the sensor network by the way of electromagnetic radiation,and the node captures the RF energy through the antenna.Compared with the fixed RF energy source,using the mobile RF energy transmitter periodically charges the node can help to reduce the cost and is more flexible and convenient.In addition,mobile data collection technology is also concerned.Therefore,how to combine both of them is a problem worth studying.The main work of this paper is as follows:In the study of mobile RF energy sources(vehicle),it is a matter of concern how to plan the mobile trajectory of a car and how to distribute the charging and data collection time to achieve a larger throughput.To solve this problem,a cluster based path planning and time allocation strategy is proposed in this paper.First,we divide all nodes in the sensor network into several clusters,and cluster points are the stationary points for the vehicle to park.The approximate solution of the traveling salesman problem is used to plan the traffic order and path of the vehicle and to allocate the time of each cluster through the number of nodes and the average residual energy.The simplex solution is used to solve the problem of charging and data collection time allocation,so as to achieve larger total throughput or common throughput.In addition,the corresponding heuristic algorithm is proposed in the range of error.Besides the model of vehicle parking at the stationary point,it is a problem worthy of research that how to allocate time in the moving process of vehicle.Compared with the parking model,the communication distance between each node and the vehicle is changing all the time during the moving process.Therefore,in this paper,the discrete model is applied to transform the charging and data collection time allocation for maximization of throughput problem to a 0-1 programming problem.Then we get the upper and lower bounds of the problem,and the optimal solution of the problem is obtained by the branch and bound method.Next,we discuss the relationship between network throughput and vehicle speed.It is proved that network throughput is independent of vehicle speed.Finally,the trajectory of the above problem is expanded from a straight line to a circle,and corresponding strategies are put forward.Experimental results show that the strategy proposed in this paper has higher throughput than traditional strategy.But,the strategy in this paper does not consider the time and energy consumption when converting between charging and data collection.