论文标题
相互耦合和单元电池意识到可重构智能表面的优化
Mutual Coupling and Unit Cell Aware Optimization for Reconfigurable Intelligent Surfaces
论文作者
论文摘要
可重新配置的智能表面（RISS）是一种新兴技术，可在低且负担得起的成本，复杂性和功耗以低和负担得起的无线网络的性能。我们引入了一种算法，用于优化单输入单输出RIS辅助系统，其中通过基于相互阻抗使用电磁兼容框架对RI进行建模。更准确地说，我们提供以下新的贡献：（i）在RIS的散射元件之间没有相互耦合的情况下，我们为最佳可调障碍提供了封闭形式的表达，这固有地说明了RIS的振幅和相位的相互作用； （ii）在存在相互耦合的情况下，我们引入了一种迭代算法，以优化RIS的可调阻抗。证明该算法是通过证明目标函数不折叠和上限的。数值结果表明，如果距离的距离小于波长的一半，则RI的散射元件之间的相互耦合会显着影响端到端信噪比（SNR）。如果通过明确考虑相互耦合的影响来优化RIS，则可以获得更好的端到端SNR。
Reconfigurable intelligent surfaces (RISs) are an emerging technology for enhancing the performance of wireless networks at a low and affordable cost, complexity, and power consumption. We introduce an algorithm for optimizing a single-input single-output RIS-assisted system in which the RIS is modeled by using an electromagnetic-compliant framework based on mutual impedances. More precisely, we provide the following new contributions: (i) in the absence of mutual coupling among the scattering elements of the RIS, we derive a closed-form expression for the optimal tunable impedances, which inherently accounts for the interplay between the amplitude and phase of the lumped loads of the RIS; and (ii) in the presence of mutual coupling, we introduce an iterative algorithm for optimizing the tunable impedances of the RIS. The algorithm is proved to be convergent by showing that the objective function is non-decreasing and upper bounded. Numerical results reveal that the mutual coupling among the scattering elements of the RIS significantly affects the end-to-end signal-to-noise ratio (SNR) if the inter-distance is less than half of the wavelength. If the RIS is optimized by explicitly taking into account the impact of mutual coupling, a better end-to-end SNR is obtained.
