AI 中文总结
研究堆叠智能超表面辅助的无人机通信系统，通过将部分波束成形功能转移到电磁域，实现节能混合波束成形。制定联合设计并开发交替优化框架，解决非凸问题。结果表明该架构能提高频谱效率且保持低硬件复杂度。
AI 中文摘要
本文研究了由堆叠智能超表面（SIM）辅助的无人机通信系统，该系统通过多个级联超表面层实现可编程波域信号处理。通过将部分波束成形功能从射频/数字域转移到电磁域，SIM允许实现适用于空中平台的节能混合波束成形架构。我们制定了用于多用户下行链路和速率最大化的数字预编码、SIM相位配置和无人机定位的联合设计。为了解决由此产生的非凸问题，我们开发了一个交替优化框架，保证目标的单调改进。数值结果表明，所提出的SIM辅助架构在保持低硬件复杂度的同时显著提高了频谱效率，并突出了超表面层数和每层尺寸对系统性能的影响。
英文摘要
In this paper, we investigate an unmanned aerial vehicle (UAV) communication system assisted by stacked intelligent metasurfaces (SIMs), which enable programmable wave-domain signal processing through multiple cascaded metasurface layers. By shifting part of the beamforming functionality from the RF/digital domain to the electromagnetic domain, SIMs allow the realization of energy-efficient hybrid beamforming architectures suitable for aerial platforms. We formulate the joint design of digital precoding, SIM phase configuration, and UAV positioning for multi-user downlink sum-rate maximization. To solve the resulting non-convex problem, we develop an alternating optimization framework that guarantees monotonic improvement of the objective. Numerical results demonstrate that the proposed SIM-assisted architecture significantly improves spectral efficiency while maintaining low hardware complexity, and highlight the impact of the number of metasurface layers and size of each layer on system performance.
