智能反射面辅助NOMA系统AOA定位算法

Reconfigurable Intelligence Surface Assisted NOMA System for An Angles of Arrival Localization Algorithm

摘要:

智能反射面(RIS)由大规模光电器件阵列组成,可以调控入射电磁波的幅度、相位等电磁特性来获得定制化的反射波束,改善非视距(NLOS)环境的无线定位服务问题。构建了一个智能反射面的非正交多址接入(NOMA)定位系统,利用部署在空中的多个RIS对基站发射给用户的信号进行反射,便于用户接收；另外,RIS利用伪随机序列对基站发射的信号进行再调制然后反射至用户,方便用户识别不同RIS反射的信号。最后,用户使用多重信号分类算法估计出多个信号到达角(AOA)来获取定位坐标。仿真结果表明,所提出的方法在NLOS环境下定位精度可达厘米级。

Abstract:

A reconfigurable intelligence surface (RIS) consists of a large-scale array of optoelectronic devices that can modulate the electromagnetic characteristics, such as the amplitude and phase, of an incident electromagnetic wave to obtain a customized reflected beam and improve the wireless positioning service problem in non-line-of-sight (NLOS) environments. In this study, a non-orthogonal multiple access (NOMA) positioning system with intelligent reflective surfaces is constructed, which uses multiple RISs deployed in the air to reflect the signals transmitted from the base station to the user for easy reception. In addition, the RISs use pseudo-random sequences to remodulate the signals transmitted from the base station and then reflect them back to the user, making it easier to identify the signals reflected from different RISs. Finally, the user estimates multiple signal angles of arrival (AOA) using the multiple signal classification (MUSIC) algorithm to obtain the positioning coordinates. The simulation results show that the method proposed in this study can achieve centimeter-level positioning accuracy in NLOS environments.