Title: Efficient Computation of Physics-Compliant Channel Realizations for (Rich-Scattering) RIS-Parametrized Radio Environments Show Chinese title

Title: 符合物理规律的（富散射）可重构智能表面参数化无线环境信道实现的有效计算

Abstract: Physics-compliant channel models of RIS-parametrized radio environments require the inversion of an "interaction matrix" to capture the mutual coupling between wireless entities (transmitters, receivers, RIS, environmental scattering objects) due to proximity and reverberation. The computational cost of this matrix inversion is typically dictated by the environmental scattering objects in non-trivial radio environments, and scales unfavorably with the latter's complexity. In addition, many problems of interest in wireless communications (RIS optimization, fast fading, object or user-equipment localization, etc.) require the computation of multiple channel realizations. To overcome the potentially prohibitive computational cost of using physics-compliant channel models, we i) introduce an isospectral reduction of the interaction matrix from the canonical basis to an equivalent reduced basis of primary wireless entities (antennas and RIS), and ii) leverage the fact that interaction matrices for different channel realizations only differ regarding RIS configurations and/or some wireless entities' locations. Show Chinese abstract

Abstract: 符合物理的 RIS 参数化无线环境的信道模型需要求逆一个“交互矩阵”以捕捉由于接近和多径效应导致的无线实体（发射机、接收机、RIS、环境散射物体）之间的相互耦合。 这种矩阵求逆的计算成本通常由非平凡无线环境中的环境散射物体决定，并且随着后者的复杂度不利地增长。 此外，无线通信中许多感兴趣的问题（RIS 优化、快衰落、物体或用户设备定位等） 需要计算多个信道实例。 为了克服使用符合物理的信道模型可能带来的过高计算成本，我们提出了一种方法：i）将交互矩阵从规范基压缩到等效的简化基（主要无线实体，即天线和 RIS），ii）利用不同信道实例的交互矩阵仅在 RIS 配置和/或某些无线实体的位置上不同的事实。