发表机构
National Key Laboratory of Wireless Communications, University of Electronic Science and Technology of China; Institute for Fundamental and Frontier Sciences, University of Electronic Science and Technology of China（电子科技大学无线通信国家重点实验室; 电子科技大学前沿交叉学院）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文针对可旋转天线赋能的低空经济网络，提出联合优化用户关联、波束成形和天线朝向的交替优化算法，并引入候选扫描和天线块方案降低复杂度，仿真验证了其相比固定天线和最近基站关联能显著提升总和速率。
AI 中文摘要
本文研究了可旋转天线（RA）赋能的低空经济（LAE）网络，其中部署多个基站（BS）以同时服务地面和空中用户。与传统固定朝向天线不同，RA可以调整其视轴以服务不同方位角和仰角的用户，从而提供三维（3D）覆盖。为了提升LAE网络的性能，我们构建了一个网络总和速率最大化问题，该问题联合优化用户关联、发射波束成形和RA朝向。然而，在此类LAE网络中，空中用户通常通过视距（LoS）链路可见多个基站，使得用户关联和干扰管理尤为困难。此外，用户关联与RA朝向紧密耦合：用户关联影响RA指向方向，而RA朝向反过来重塑用户关联的信道条件。为解决该问题，我们提出了一种交替优化（AO）算法，该算法集成了用于发射波束成形的加权最小均方误差（WMMSE）、用于用户关联的投影梯度上升更新以及用于RA朝向的Frank-Wolfe更新。此外，我们开发了一种离散候选扫描方案，用有限搜索替代连续朝向优化以降低计算复杂度。我们还提出了一种基于天线块的方案以减少朝向变量的数量。仿真结果表明，所提出的联合设计相比固定天线朝向和最近基站关联基准实现了更高的总和速率。此外，候选扫描和基于块的方案在高发射功率下分别达到约89.9%和94.3%的性能，同时降低了朝向更新的复杂度。
英文摘要
This paper investigates rotatable antenna (RA)-enabled low-altitude economy (LAE) networks, where multiple base stations (BSs) are deployed to serve both terrestrial and aerial users. Unlike conventional fixed orientation antennas, RAs can adjust their boresights to serve users at diverse azimuth and elevation angles, thereby providing three-dimensional (3D) coverage. To improve the performance of LAE networks, we formulate a network sum-rate maximization problem that jointly optimizes user association, transmit beamforming, and RA orientations. However, in such LAE networks, aerial users are often visible to multiple BSs through line-of-sight (LoS) links, making user association and interference management particularly challenging. Moreover, user association and RA orientations are closely coupled: user association affects the RA pointing directions, while the RA orientations in turn reshape the channel conditions for user association. To solve this problem, we propose an alternating optimization (AO) algorithm that integrates weighted minimum mean-square error (WMMSE) for transmit beamforming, projected gradient ascent updates for user association, and Frank-Wolfe updates for RA orientations. Furthermore, we develop a discrete candidate-scanning scheme that replaces continuous orientation optimization with a finite search to reduce computational complexity. We also propose an antenna block-based scheme to reduce the number of orientation variables. Simulation results show that the proposed joint design achieves a higher sum-rate than the fixed antenna orientation and nearest BS association benchmarks. Moreover, the candidate-scanning and block-based schemes achieve approximately 89.9% and 94.3% of the performance with high transmit power, respectively, while reducing the complexity of orientation updates.
