论文标题
两次尺度的联合预编码设计和RIS优化用于近场MIMO系统中的用户跟踪
Two-Timescale Joint Precoding Design and RIS Optimization for User Tracking in Near-Field MIMO Systems
论文作者
论文摘要
在本文中，我们提出了一个新颖的框架，旨在共同设计多个RISS的反射系数以及单个BS的预编码策略，以优化位置的自我跟踪和单个多端na UE的速度，以在远场或近场区域移动。与文献不同，为了使总体复杂性负担得起，我们假设RIS优化的频率低于本地化和预编码适应性。提出的程序导致在UE位置在两个随后的优化步骤之间不确定性区域中接收功率的倒数最小化。 将最佳的RIS和预编码器策略与经典梁的策略进行了比较，并与最大化通信速率的方案进行了比较。结果表明，如果对通信进行了优化，则用于跟踪目的时，其配置是次优的。 数值结果表明，在典型的室内环境中，只有一个BS和几毫米波动的RISS，可以实现少于半米的高位置精度。
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.
