Distributed Channel Estimation and Optimization for 6D Movable Antenna: Unveiling Directional Sparsity

Shao X, Zhang R, Jiang Q, Park J, Quek TQ, Schober R (2025)

Publication Language: English

Publication Type: Journal article

Publication year: 2025

Journal

IEEE Journal of Selected Topics in Signal Processing Institute of Electrical and Electronics Engineers (IEEE)

Book Volume: 19

Pages Range: 349-365

Journal Issue: 2

DOI: 10.1109/JSTSP.2025.3539085

Abstract

Six-dimensional movable antenna (6DMA) is an innovative and transformative technology to improve wireless network capacity by adjusting the 3D positions and 3D rotations of antennas/antenna surfaces based on the channel spatial distribution. In order to achieve optimal antenna positions and rotations, the acquisition of statistical channel state information (CSI) is essential for 6DMA systems. However, the existing works on 6DMA have assumed a central processing unit (CPU) to jointly process the signals of all 6DMA surfaces. This inevitably incurs prohibitively high processing cost and latency for channel estimation due to the vast numbers of 6DMA candidate positions/rotations and antenna elements. To tackle this issue, we propose a distributed 6DMA processing architecture to reduce the processing complexity of the CPU by equipping each 6DMA surface with a local processing unit (LPU). Furthermore, we unveil for the first time directional sparsity property of the 6DMA channels with respect to the distributed users, where each user has significant channel gains only for a (small) subset of 6DMA position-rotation pairs. Based on this property, we propose a practical three-stage protocol for the 6DMA system and corresponding algorithms to conduct statistical CSI acquisition for all 6DMA candidate positions/rotations, 6DMA position/rotation optimization based on statistical CSI, and instantaneous CSI estimation for user data transmission given the optimized 6DMA positions/rotations. Simulation results show that the proposed channel estimation algorithms achieve higher accuracy than benchmark schemes, while requiring a lower pilot overhead. Furthermore, it is shown that the proposed 6DMA system with statistical CSI-based position and rotation optimization outperforms fixed-position antenna systems and fluid antenna systems with antenna position optimization only in terms of the users' ergodic sum rate, even if the latter systems have perfect instantaneous CSI.

Authors with CRIS profile

Xiaodan Shao Lehrstuhl für Digitale Übertragung (IDC) Robert Schober Lehrstuhl für Digitale Übertragung (IDC)

Involved external institutions

The Chinese University of Hong Kong (CUHK) CN China (CN) National University of Singapore (NUS) SG Singapore (SG)

How to cite

APA:

Shao, X., Zhang, R., Jiang, Q., Park, J., Quek, T.Q., & Schober, R. (2025). Distributed Channel Estimation and Optimization for 6D Movable Antenna: Unveiling Directional Sparsity. IEEE Journal of Selected Topics in Signal Processing, 19(2), 349-365. https://doi.org/10.1109/JSTSP.2025.3539085

MLA:

Shao, Xiaodan, et al. "Distributed Channel Estimation and Optimization for 6D Movable Antenna: Unveiling Directional Sparsity." IEEE Journal of Selected Topics in Signal Processing 19.2 (2025): 349-365.

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