一种射频能量捕获网络移动能量源均衡化充电策略

A Balanced Charging Scheme for Mobile Energy Transmitter in RF Energy Harvesting Network

为解决传统电池供电传感器网络存在的电池不易更换、节点能量容易耗尽等问题,射频能量捕获技术已逐步应用于无线可充电传感器网络中.由于不同位置传感器节点的工作负荷不同,捕获能量也有差异,实现节点能量的均衡化分布可以有效地提高节点的存活率.考虑射频能量源移动充电的场景,在已知节点位置信息的条件下,设计合理均衡的路由方案和充电算法.首先将区域基于蜂窝六边形网格划分,分别对网格和节点分层,提出逐层传输的均衡式路由策略,然后给出无线充电小车的移动路径,对相邻两层内节点剩余能量的方差最小化问题建模,由内层向外层依次确定能量源在各停留点的充电时间.仿真结果表明,相比已有的均衡化充电方法,该策略可以明显提高节点剩余能量的均衡性,从而延长网络的生命周期.

In order to solve the problems existing in the traditional battery-powered sensor network that the battery is not available to replace and the energy of nodes is easy to be exhausted,RF energy harvesting technology has been applied to the wireless rechargeable sensor network.Since the workload and harvested energy of sensor nodes in different positions are different,balanced distribution of nodes’energy can effectively improve the survival rate of nodes.Considering the scenario where mobile RF energy transmitter is employed for charging,we design a reasonable balanced routing scheme and charging algorithm under the conditions of known nodes’location information.First,the network area is discretized based on the cellular hexagonal grid where the grids and nodes are stratified respectively.A balanced routing scheme of hierarchical data transmission is proposed.Then we formulate mathematic model with pre-defined energy transmitter’s moving path to minimize the variance of the nodes’residual energy in the adjacent two layers and derive the charging time at different charging spots from the inner layer to the outer layer.Simulation results reveal that compared with the existing balanced charging method,our proposed algorithm can significantly improve the balance of node’s residual energy and prolong the network lifetime.