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, by departing from a recently proposed model based on mutually coupled loaded wire dipoles. While existing related research focuses on free-space wireless channels or ignore the interactions between the RIS and the scattering objects present in the propagation environment, we introduce an RIS-aided channel model that is applicable to more realistic scenarios, which include the presence of scattering objects that are modeled as loaded wire dipoles. By adjusting the parameters of the wire dipoles and the loads, the properties of general natural and engineered material objects can be modeled. We introduce a provably convergent and efficient iterative algorithm that jointly optimizes the RIS and base station 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）是一种正在改变无线网络认知方式的新兴技术，因此其潜在优势与应用正处于深入研究和探索阶段。本文基于近期提出的互耦加载线偶极子模型，聚焦于RIS的电磁一致性建模。现有相关研究多关注自由空间无线信道，或忽略RIS与传播环境中散射物之间的相互作用，而我们引入了一种适用于更现实场景的RIS辅助信道模型，该模型考虑了以加载线偶极子建模的散射物存在。通过调整线偶极子及其负载参数，可模拟一般自然材料与工程材料的特性。我们提出了一种可证明收敛且高效迭代算法，联合优化RIS与基站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，所提方法能显著提升网络性能。