Optimal Placement of Movable Antennas for Angle-of-Departure Estimation Under User Location Uncertainty

TL;DR

This paper explores how movable antennas at base stations can be optimally positioned to improve angle-of-departure estimation accuracy despite user location uncertainties, using theoretical bounds and optimization.

Contribution

It introduces a method to optimize movable antenna placement considering user location uncertainty, enhancing AoD estimation performance over fixed arrays.

Findings

Optimized antenna placement improves AoD estimation accuracy.

Dynamic antenna positioning outperforms fixed array configurations.

Theoretical bounds validate the robustness of the proposed method.

Abstract

Movable antennas (MA) have gained significant attention in recent years to overcome the limitations of extremely large antenna arrays in terms of cost and power consumption. In this paper, we investigate the use of MA arrays at the base station (BS) for angle-of-departure (AoD) estimation under uncertainty in the user equipment (UE) location. Specifically, we (i) derive the theoretical performance limits through the Cram\'er-Rao bound (CRB) and (ii) optimize the antenna positions to ensure robust performance within the UE's uncertainty region. Numerical results show that dynamically optimizing antenna placement by explicitly considering the uncertainty region yields superior performance compared to fixed arrays, demonstrating the ability of MA systems to adapt and outperform conventional arrays.