In this paper, we propose a novel framework that aims to jointly design the reflection coefficients of multiple RISs and the precoding strategy of a single BS to optimize the self-tracking of the position and the velocity of a single multi-antenna UE that moves either in the far- or near-field region. Differently from the literature, and to keep the overall complexity affordable, we assume that RIS optimization is performed less frequently than localization and precoding adaptation. The proposed procedure leads to minimize the inverse of the received power in the UE position uncertainty area between two subsequent optimization steps. The optimal RIS and precoder strategy are compared with the classical beam-focusing strategy and with a scheme that maximizes the communication rate. It is shown that if the RISs are optimized for communications, their configuration is suboptimal when used for tracking purposes. Numerical results show that in typical indoor environments with only one BS and a few RISs operating on millimeter waves, high location accuracy in the range of less than half a meter can be achieved.

翻译：本文提出了一种新颖框架，旨在联合优化多个智能反射面（RIS）的反射系数与单个基站（BS）的预编码策略，以实现远场或近场区域移动的单天线用户设备（UE）位置与速度的自跟踪。与现有文献不同，为控制整体复杂度，假设RIS优化的执行频率低于定位与预编码自适应。所提方法旨在最小化两次优化步骤之间用户位置不确定区域内的接收功率逆值。将最优RIS与预编码策略同经典波束聚焦策略及最大化通信速率的方案进行了比较。结果表明，若RIS针对通信进行优化，其配置在用于跟踪任务时并非最优。数值结果显示，在仅有单个基站和少量工作于毫米波频段RIS的典型室内环境中，可实现低于半米的高精度定位。