AI 中文总结
针对无人机近场通信的传统模型缺陷，提出动态端口可重构近场信道模型，开发FAS自适应子阵划分与信道增益选择策略，分析系统性能与复杂度，为动态场景FAS设计提供理论基础。
AI 中文摘要
流体天线系统（FAS）通过实现可重构的辐射特性，为无人机（UAV）空对地（A2G）通信提供了一种有前景的解决方案。针对传统模型在捕捉FAS的动态端口配置以及无人机通信的近场特性方面的局限性，本文提出了一种用于FAS辅助的无人机到移动用户（MU）链路的动态端口可重构近场信道模型。此外，我们开发了一种利用贪心策略的FAS自适应子阵划分方案。通过分解视距（LoS）和非视距（NLoS）分量，并将无人机运动动态与FAS端口激活状态相结合，所提模型准确表征了近场信道的非均匀空间分布。该子阵划分方案动态分组激活端口以满足近场条件，同时显著降低计算复杂度，由一种动态更新算法支撑，该算法可在端口切换期间高效处理子阵调整。为避免密集FAS配置中出现低有效增益和深衰落端口，采用了基于信道增益的选择策略以优先选择高增益端口。我们推导并分析了建模精度和信道容量，研究了FAS尺寸、端口间距、激活端口数量以及无人机动态对系统性能的影响。最后，评估了子阵划分方案的计算复杂度，验证了其在实时应用中的优势，并为动态场景下FAS的设计与分析提供了理论基础。
英文摘要
Fluid antenna systems (FASs) offer a promising solution for unmanned aerial vehicle (UAV) air-to-ground (A2G) communications by enabling reconfigurable radiation characteristics. Addressing the limitations of traditional models in capturing the dynamic port configuration of FAS and the near-field nature of UAV communications, this paper proposes a dynamic port-reconfigurable near-field channel model for FAS-assisted UAV-to-mobile user (MU) links. Furthermore, we develop a FAS-adaptive subarray partition scheme utilizing a greedy strategy. By decomposing line-of-sight (LoS) and non-line-of-sight (NLoS) components and integrating UAV motion dynamics with FAS port activation states, the proposed model accurately characterizes the non-uniform spatial distribution of near-field channels. The subarray partition scheme dynamically groups active ports to satisfy near-field conditions while significantly reducing computational complexity, supported by a dynamic update algorithm that efficiently handles subarray adjustments during port switching. To avoid low effective gain and deep-fading ports in dense FAS configurations, a channel gain-based selection strategy is employed to prioritize high-gain ports. We derive and analyze the modeling accuracy and channel capacity, investigating the impact of FAS dimensions, port spacing, active port count, and UAV dynamics on system performance. Finally, the computational complexity of the subarray partition scheme is evaluated, verifying its advantages for real-time applications and providing a theoretical foundation for the design and analysis of FAS in dynamic scenarios.
