Movable Antennas: Channel Measurement, Modeling, and Performance Evaluation

TL;DR

The paper tackles underutilization of spatial diversity in fixed-position antennas by exploring Movable Antenna (MA) systems in THz channels. It combines a high-resolution 2D MA measurement campaign (260–320 GHz) with a measurement-driven, complex covariance-based channel model, a low-complexity uniform-region SINR-optimized port selection, and beamforming to evaluate spectral efficiency. Key contributions include a 0.02 mm resolution MA measurement across 32×32 ports, a practical two-ray channel model validated by data, and a parameterized spatial-covariance framework that enables realistic MA-system simulations. Results show MA configurations can boost spectral efficiency by up to approximately 11.5% and can reach about 99% of the optimal performance under greedy port selection, highlighting MA as a viable approach to mitigate multipath fading in THz bands.

Abstract

Since decades ago, multi-antenna has become a key enabling technology in the evolution of wireless communication systems. In contrast to conventional multi-antenna systems that contain antennas at fixed positions, position-flexible antenna systems have been proposed to fully utilize the spatial variation of wireless channels. In this paper, movable antenna (MA) systems are analyzed from channel measurement, modeling, position optimization to performance evaluation. First, a broadband channel measurement system with physical MAs is developed, for which the extremely high movable resolution reaches 0.02 mm. A practical two-ray model is constructed based on the channel measurement for a two-dimensional movable antenna system across 32$\times$32 planar port positions at 300 GHz. In light of the measurement results, spatial-correlated channel models for the two-dimensional MA system are proposed, which are statistically parameterized by the covariance matrix of measured channels. Finally, the signal-to-interference-and-noise ratio (SINR)-maximized position selection algorithm is proposed, which achieves 99% of the optimal performance. The performance of different MA systems in terms of spectral efficiency are evaluated and compared for both planar and linear MA systems. Extensive results demonstrate the advantage of MAs over fixed-position antennas in coping with the multi-path fading and improving the spectral efficiency by 10% in a 300 GHz measured channel.

Figures (14)

• Figure 1: Overview of the measurement platform for MA systems and the measurement scenario.
• Figure 2: The CIR result at the center of Tx antenna ports.
• Figure 3: Gain and phase change of the LoS ray across $32\times32$ port positions.
• Figure 4: Gain and phase change of the reflected ray across $32\times32$ port positions.
• Figure 5: Superposition of the LoS ray and the reflected ray.