Movable Antenna Enabled Reconfigurable Array Topologies for Structured Beam Communications

TL;DR

This paper introduces a reconfigurable structured beam communication framework using movable antennas to optimize array topologies and beamforming, significantly improving spectrum efficiency in 6G networks.

Contribution

It proposes a novel MA-based geometric modeling framework and joint optimization algorithm for array topology and beamforming, enabling adaptable and efficient structured beam communications.

Findings

Enhanced spectrum efficiency compared to fixed-position antenna schemes.

Effective reconfiguration of array topologies using movable antennas.

Significant performance gains demonstrated through numerical simulations.

Abstract

Spatially structured beams have emerged as a promising technology for enhancing spectrum efficiency (SE) in sixth-generation (6G) networks. However, structured beam schemes based on fixed-position antennas (FPAs) fail to fully exploit the array aperture, thereby limiting their topological reconfigurability and adaptability to diverse communication scenarios. To overcome these limitations, this paper proposes a novel structured beam communication framework exploiting movable antennas (MAs) to achieve reconfigurable array topologies. Specifically, we develop an MA-based geometric modeling framework to construct a variety of practical array topologies, thereby enabling the realization of diverse array configurations utilizing a unified hardware platform. Furthermore, we investigate the joint design of the array topology and the structured beamforming vector to efficiently exploit the array aperture and facilitate the multiplexing of orthogonal spatial modes. Accordingly, we formulate the corresponding beam generation and demodulation schemes and derive the channel gains under varying array topologies. We also propose an alternating optimization algorithm to jointly optimize the array topology configuration, the antenna element positions, and the structured beamforming vector, with the aim of maximizing the system SE. Numerical results demonstrate that the proposed joint design significantly enhances the SE compared to conventional FPA schemes. By synergizing the spatial multiplexing degrees of freedom (DoFs) of structured beams with the mobility DoFs of MAs within 2D planar regions, this work establishes a reconfigurable and practical framework for structured beam-based wireless communications.