Spatially Reconfigurable Antenna Arrays for 6G Networks: Modeling, Methods, and Applications

Abstract

Spatially reconfigurable antenna arrays (SRAAs) have recently emerged as a promising paradigm for enhancing wireless system performance by treating antenna position and orientation as new spatial degrees of freedom (DoFs). Unlike conventional fixed-geometry antenna arrays, SRAAs enable geometry-aware adaptation of the physical aperture, thereby allowing wireless systems to actively exploit spatial channel variations beyond signal-domain processing. This capability is particularly attractive for future sixth-generation (6G) networks that operate in highly dynamic propagation environments and face stringent performance requirements. This review provides a comprehensive and system-oriented overview of SRAAs from both theoretical and practical perspectives. Firstly, we present a unified and geometry-aware channel modeling framework for spatial reconfiguration at different architectural granularities. Secondly, we analyze how position- and orientation-induced channel variations, along with their combined effects, and enable performance gains without relying solely on massive antenna scaling. Afterwards, we survey design and optimization methods for position-orientation reconfiguration, covering both model- and learning-based techniques. Practical considerations are also discussed through a systematic review of hardware implementation options and channel estimation techniques under spatial reconfiguration. To further illustrate the system-level benefits of SRAAs, representative applications are examined, including point-to-point and multiuser multiple-input multiple-output (MIMO), cell-free massive MIMO, as well as aerial and mobile communications. A dedicated case study on six-dimensional aerial rotatable antenna (6DARA)-enabled cell-free networks is provided to demonstrate how array-wise position and orientation control, combined with distributed optimization, can achieve substantial performance gains with manageable complexity. Finally, we outline key issues and future directions for the large-scale and practical deployment of SRAAs in 6G wireless networks.