Fluid Aerial Networks: UAV Rotation for Inter-Cell Interference Mitigation

2025-07-01

AI Summary

To address severe inter-cell interference and limited spectral efficiency in unmanned aerial vehicle (UAV)-enabled aerial base station (ABS) deployments, this paper proposes a dynamic beamforming method leveraging ABS attitude control. Exploiting the UAV’s three-dimensional rotational degrees of freedom, the approach jointly optimizes the azimuth and elevation angles of a two-dimensional antenna array to minimize user channel correlation and maximize multi-user multiplexing gain under line-of-sight-dominant channels. Unlike conventional fixed-orientation ABS deployments, the proposed low-complexity sequential rotation algorithm uses directional angles as optimization variables, achieving a favorable trade-off between computational efficiency and performance. Simulation results demonstrate that, under interference-limited conditions, the scheme improves the multi-cell sum rate by approximately 10% over baseline methods while significantly suppressing inter-cell interference. This work establishes a practically deployable interference coordination paradigm for high-density air-ground integrated networks.

Technology Category

• Planning, Routing, and Scheduling: Optimization of Spatio-temporal Systems
• Search and Optimization: Sampling/Simulation-based Search
• Intelligent Robots: Learning & Optimization for ROB

Application Category

• User Modeling, Personalization and Recommendation: On-Device user modeling, personalization, and recommendation
• Graph Algorithms and Modeling for the Web: Efficient manipulation of static and dynamic Web-related graphs
• Systems and Infrastructure for Web, Mobile and WoT: Energy management for devices in mobile Web and WoT environments

Abstract

With the rapid development of aerial infrastructure, unmanned aerial vehicles (UAVs) that function as aerial base stations (ABSs) extend terrestrial network services into the sky, enabling on-demand connectivity and enhancing emergency communication capabilities in cellular networks by leveraging the flexibility and mobility of UAVs. In such a UAV-assisted network, this paper investigates position-based beamforming between ABSs and ground users (GUs). To mitigate inter-cell interference, we propose a novel fluid aerial network that leverages ABS rotation to increase multi-cell capacity and overall network efficiency. Specifically, considering the line-of-sight channel model, the spatial beamforming weights are determined by the orientation angles of the GUs. In this direction, we examine the beamforming gain of a two-dimensional multiple-input multiple-output (MIMO) array at various ground positions, revealing that ABS rotation significantly affects multi-user channel correlation and inter-cell interference. Based on these findings, we propose an alternative low-complexity algorithm to design the optimal rotation angle for ABSs, aiming to reduce inter-cell interference and thus maximize the sum rate of multi-cell systems. In simulations, exhaustive search serves as a benchmark to validate the optimization performance of the proposed sequential ABS rotation scheme. Moreover, simulation results demonstrate that, in interference-limited regions, the proposed ABS rotation paradigm can significantly reduce inter-cell interference in terrestrial networks and improve the multi-cell sum rate by approximately 10% compared to fixed-direction ABSs without rotation.

Problem

• Mitigates inter-cell interference in UAV-assisted networks
• Optimizes ABS rotation to enhance multi-cell capacity
• Improves network efficiency via low-complexity beamforming algorithm

Innovation

• UAV rotation mitigates inter-cell interference
• Optimal rotation angle algorithm enhances sum rate
• MIMO beamforming adapts to ground user angles