多天线无线充电器的安全布置研究

Safe Placement of Multi-antenna Wireless Chargers

多天线无线充电器的安全布置问题(SPINNER)涉及给定一组无线可充电设备和一组无线充电器,每个充电器都配备了多根有向天线,需确定其功率水平和策略(包括充电器的位置和天线方向),以最大化整体充电效用,并确保目标区域内任意位置均满足电磁辐射安全约束。文中考虑了两种场景,分别是具有给定位置集的多天线无线充电器的安全布置(SPINNER-G)和具有任意点的多天线无线充电器的安全布置(SPINNER-A)。首先,采用分段常数函数近似非线性充电功率函数,并将二维区域划分为有限数量的子区域,使得无限的电磁辐射安全约束减少为有限个。然后,针对SPINNER-G,提出了一种最大覆盖集提取方法,以限制无线充电器的方向。针对SPINNER-A,构造了最大相交情况,以限制充电器的位置和方向。文中提出了两种基于线性规划的贪心方案,分别求解SPINNER-G和SPINNER-A,近似比均为1/2-ε。仿真结果表明,所提算法在充电效用方面相比3种对比算法至少提高了54.2%。

This paper studies the problem of safe placement of multi-antenna wireless chargers(SPINNER),that is,given a set of wireless rechargeable devices and a set of wireless chargers,each equipped with multiple directional antennas,scheduling both the power level and the strategy(the position and the orientations of antennas)of each charger,so that the overall charging utility can be maximized and any position in the field satisfies electromagnetic radiation(EMR)safety constraints.In this paper,we consider two different scenarios,that is,safe placement of multi-antenna wireless chargers with a given position set(SPINNER-G)and safe placement of multi-antenna wireless chargers with arbitrary points(SPINNER-A).First,we adopt a piecewise constant function to approximate the nonlinear charging power function and partition the 2D field into a limited number of subareas.Thus,the number of EMR constraints is limited.Then,for SPINNER-G,we propose a maximal coverage set extraction method to further limit the number of orientations of chargers.For SPINNER-A,we construct maximal intersection condition set to limit the searching space for the positions and orientations of chargers.Then,for SPINNER-G and SPINNER-A,we propose two linear programming based greedy schemes,both of which achieve an approximation ratio of 1/2-ε.Simulations show that the charging utility of our algorithm improves by at least 54.2%comparte to the three comparison algorithms.