UAV-Enabled Passive 6D Movable Antenna for ISAC: Joint Location, Orientation, and Reflection Optimization

TL;DR

This paper introduces a UAV-mounted intelligent reflecting surface with 6D maneuverability to optimize sensing and communication performance in ISAC systems, achieving significant improvements through joint location, orientation, and reflection optimization.

Contribution

It proposes a novel passive 6D movable antenna system using UAV-mounted IRS for joint optimization in ISAC, addressing a key performance trade-off.

Findings

Significant improvement in sensing and communication performance.

Enhanced channel correlations and power gains.

Outperforms baseline schemes in simulations.

Abstract

Improving the fundamental performance trade-off in integrated sensing and communication (ISAC) systems has been deemed as one of the most significant challenges. To address it, we propose in this letter a novel ISAC system that leverages an unmanned aerial vehicle (UAV)-mounted intelligent reflecting surface (IRS) and the UAV's maneuverability in six-dimensional (6D) space, i.e., three-dimensional (3D) location and 3D rotation, thus referred to as passive 6D movable antenna (6DMA). We aim to maximize the signal-to-noise ratio (SNR) for sensing a single target while ensuring a minimum SNR at a communication user equipment (UE), by jointly optimizing the transmit beamforming at the ISAC base station (BS), the 3D location and orientation as well as the reflection coefficients of the IRS. To solve this challenging non-convex optimization problem, we propose a two-stage approach. In the first stage, we aim to optimize the IRS's 3D location, 3D orientation, and reflection coefficients to enhance both the channel correlations and power gains for sensing and communication. Given their optimized parameters, the optimal transmit beamforming at the ISAC BS is derived in closed form. Simulation results demonstrate that the proposed passive 6DMA-enabled ISAC system significantly improves the sensing and communication trade-off by simultaneously enhancing channel correlations and power gains, and outperforms other baseline schemes.