Wireless Communication for Low-Altitude Economy with UAV Swarm Enabled Two-Level Movable Antenna System

2025-05-28

AI Summary

To address the minimum achievable rate constraint for ground users in low-altitude economy scenarios, this paper proposes a two-tier reconfigurable antenna system based on UAV swarms: each UAV hosts a locally tunable antenna array, while swarm-level coordination establishes a large-scale, aerial distributed antenna system. We jointly optimize UAVs’ 3D positions, per-UAV antenna placement, and user-side receive beamforming to maximize the worst-case user rate. Theoretically, we derive, for the first time, a closed-form solution for uniform sparse arrays in the two-user interference-free case. Algorithmically, we design an efficient alternating optimization framework to tackle the multi-user non-convex problem. Experiments demonstrate that the proposed method significantly improves the minimum user rate over baseline schemes, exhibiting superior robustness and spectral efficiency in both dense urban and wide-area coverage scenarios.

Technology Category

• Planning, Routing, and Scheduling: Optimization of Spatio-temporal Systems
• Search and Optimization: Algorithm Configuration
• Constraint Satisfaction and Optimization: Distributed CSP/Optimization

Application Category

• Systems and Infrastructure for Web, Mobile and WoT: Experiences and lessons learnt from Web-based algorithms and system deployments
• User Modeling, Personalization and Recommendation: Federated recommendation systems and personalization
• Economics, Online Markets and Human Computation: Incentives in network design for Web infrastructures and ecosystems

Abstract

Unmanned aerial vehicle (UAV) is regarded as a key enabling platform for low-altitude economy, due to its advantages such as 3D maneuverability, flexible deployment, and LoS air-to-air/ground communication links. In particular, the intrinsic high mobility renders UAV especially suitable for operating as a movable antenna (MA) from the sky. In this paper, by exploiting the flexible mobility of UAV swarm and antenna position adjustment of MA, we propose a novel UAV swarm enabled two-level MA system, where UAVs not only individually deploy a local MA array, but also form a larger-scale MA system with their individual MA arrays via swarm coordination. We formulate a general optimization problem to maximize the minimum achievable rate over all ground UEs, by jointly optimizing the 3D UAV swarm placement positions, their individual MAs' positions, and receive beamforming for different UEs. We first consider the special case where each UAV has only one antenna, under different scenarios of one single UE, two UEs, and arbitrary number of UEs. In particular, for the two-UE case, we derive the optimal UAV swarm placement positions in closed-form that achieves IUI-free communication, where the UAV swarm forms a uniform sparse array (USA) satisfying collision avoidance constraint. While for the general case with arbitrary number of UEs, we propose an efficient alternating optimization algorithm to solve the formulated non-convex optimization problem. Then, we extend the results to the case where each UAV is equipped with multiple antennas. Numerical results verify that the proposed low-altitude UAV swarm enabled MA system significantly outperforms various benchmark schemes, thanks to the exploitation of two-level mobility to create more favorable channel conditions for multi-UE communications.

Problem

• Optimizing UAV swarm placement for better wireless communication
• Maximizing achievable rate via two-level movable antenna system
• Enhancing multi-UE communications with UAV swarm coordination

Innovation

• UAV swarm enabled two-level MA system
• 3D UAV swarm and MA position optimization
• Alternating optimization for non-convex problem