Efficient Channel Estimation for Rotatable Antenna-Enabled Wireless Communication

TL;DR

This paper introduces an efficient channel estimation method for rotatable antenna systems that adaptively adjusts antenna orientations to improve CSI accuracy and overall communication performance.

Contribution

It proposes a novel adaptive channel estimation scheme that sequentially estimates CSI and optimally adjusts antenna orientations for enhanced performance.

Findings

Outperforms benchmark schemes in simulation

Improves channel estimation accuracy

Enhances effective channel gain

Abstract

Non-fixed flexible antenna architectures, such as fluid antenna system (FAS), movable antenna (MA), and pinching antenna, have garnered significant interest in recent years. Among them, rotatable antenna (RA) is a promising antenna architecture that exploits additional spatial degrees of freedom (DoFs) to enhance the communication performance. To fully obtain the performance gain provided by RAs, accurate channel state information (CSI) is essential for adjusting the orientation/boresight of each antenna. In this letter, we propose an efficient channel estimation scheme for RA communication systems, where the base station (BS) can sequentially and adaptively adjust the orientations of RAs to enrich the environmental observations from diverse angular perspectives, thereby enhancing the channel estimation accuracy. The proposed scheme includes two main procedures that are conducted alternately during each channel training period. Specifically, the first procedure is to estimate the CSI with given RAs' orientations, involving the angle-of-arrivals (AoAs) information and path gains. Then, based on the estimated CSI, the second procedure adjusts the RAs' orientations to maximize the effective channel gain. Simulation results demonstrate that the proposed channel estimation method outperforms other benchmark schemes.