The reconfigurable intelligent surface (RIS) is an emerging technology that changes how wireless networks are perceived, therefore its potential benefits and applications are currently under intense research and investigation. In this letter, we focus on electromagnetically consistent models for RISs inheriting from a recently proposed model based on mutually coupled loaded wire dipoles. While existing related research focuses on free-space wireless channels thereby ignoring interactions between RIS and scattering objects present in the propagation environment, we introduce an RIS-aided channel model that is applicable to more realistic scenarios, where the scattering objects are modeled as loaded wire dipoles. By adjusting the parameters of the wire dipoles, the properties of general natural and engineered material objects can be modeled. Based on this model, we introduce a provably convergent and efficient iterative algorithm that jointly optimizes the RIS and transmitter configurations to maximize the system sum-rate. Extensive numerical results show the net performance improvement provided by the proposed method compared with existing optimization algorithms.

翻译：可重构智能表面（RIS）是一种新兴技术，正在改变人们对无线网络的认知，因此其潜在优势和应用目前正受到广泛研究与探索。本文聚焦于基于最近提出的相互耦合加载线偶极子模型的RIS电磁一致性模型。现有相关研究主要关注自由空间无线信道，忽略了RIS与传播环境中散射物体之间的相互作用，而我们提出了一种适用于更真实场景的RIS辅助信道模型，其中散射物体被建模为加载线偶极子。通过调整线偶极子的参数，可以模拟一般天然和人造材料物体的特性。基于这一模型，我们提出了一种可证明收敛且高效的迭代算法，该算法联合优化RIS与发射机配置以最大化系统总速率。大量数值结果表明，与现有优化算法相比，所提方法能够带来显著的性能提升。