Title: Radiation Pattern Reconfigurable FAS-Empowered Interference-Resilient UAV Communication Show Chinese title

Title: 可重构辐射波束的FAS增强型抗干扰无人机通信

Abstract: The widespread use of uncrewed aerial vehicles (UAVs) has propelled the development of advanced techniques on countering unauthorized UAV flights. However, the resistance of legal UAVs to illegal interference remains under-addressed. This paper proposes radiation pattern reconfigurable fluid antenna systems (RPR-FAS)-empowered interference-resilient UAV communication scheme. This scheme integrates the reconfigurable pixel antenna technology, which provides each antenna with an adjustable radiation pattern. Therefore, RPR-FAS can enhance the angular resolution of a UAV with a limited number of antennas, thereby improving spectral efficiency (SE) and interference resilience. Specifically, we first design dedicated radiation pattern adapted from 3GPP-TR-38.901, where the beam direction and half power beamwidth are tailored for UAV communications. Furthermore, we propose a low-storage-overhead orthogonal matching pursuit multiple measurement vectors algorithm, which accurately estimates the angle-of-arrival (AoA) of the communication link, even in the single antenna case. Particularly, by utilizing the Fourier transform to the radiation pattern gain matrix, we design a dimension-reduction technique to achieve 1--2 order-of-magnitude reduction in storage requirements. Meanwhile, we propose a maximum likelihood interference AoA estimation method based on the law of large numbers, so that the SE can be further improved. Finally, alternating optimization is employed to obtain the optimal uplink radiation pattern and combiner, while an exhaustive search is applied to determine the optimal downlink pattern, complemented by the water-filling algorithm for beamforming. Comprehensive simulations demonstrate that the proposed schemes outperform traditional methods in terms of angular sensing precision and spectral efficiency. Show Chinese abstract

Abstract: 无人机（UAV）的广泛应用推动了应对未经授权的无人机飞行的先进技术的发展。 然而，合法无人机对非法干扰的抵抗仍未得到充分解决。 本文提出了一种基于可重构辐射波束流体天线系统（RPR-FAS）的抗干扰无人机通信方案。 该方案结合了可重构像素天线技术，为每个天线提供可调整的辐射波束。 因此，RPR-FAS可以在天线数量有限的情况下提高无人机的角度分辨率，从而提高频谱效率（SE）和抗干扰能力。 具体而言，我们首先设计了从3GPP-TR-38.901改编的专用辐射波束，其中波束方向和半功率波束宽度针对无人机通信进行了优化。 此外，我们提出了一种低存储开销的正交匹配追踪多测量向量算法，即使在单天线情况下也能准确估计通信链路的到达角度（AoA）。 特别是，通过将辐射波束增益矩阵进行傅里叶变换，我们设计了一种降维技术，实现了存储需求一到两个数量级的减少。 同时，我们提出了一种基于大数定律的最大似然干扰AoA估计方法，以进一步提高SE。 最后，采用交替优化来获得最优上行辐射波束和组合器，而采用穷举搜索来确定最优下行波束，并通过水填充算法进行波束成形。 全面的仿真结果表明，所提出的方案在角度感知精度和频谱效率方面优于传统方法。