Movable antenna (MA) is a new technology with great potential to improve communication performance by enabling local movement of antennas for pursuing better channel conditions. In particular, the acquisition of complete channel state information (CSI) between the transmitter (Tx) and receiver (Rx) regions is an essential problem for MA systems to reap performance gains. In this paper, we propose a general channel estimation framework for MA systems by exploiting the multi-path field response channel structure. Specifically, the angles of departure (AoDs), angles of arrival (AoAs), and complex coefficients of the multi-path components (MPCs) are jointly estimated by employing the compressed sensing method, based on multiple channel measurements at designated positions of the Tx-MA and Rx-MA. Under this framework, the Tx-MA and Rx-MA measurement positions fundamentally determine the measurement matrix for compressed sensing, of which the mutual coherence is analyzed from the perspective of Fourier transform. Moreover, two criteria for MA measurement positions are provided to guarantee the successful recovery of MPCs. Then, we propose several MA measurement position setups and compare their performance. Finally, comprehensive simulation results show that the proposed framework is able to estimate the complete CSI between the Tx and Rx regions with a high accuracy.

翻译：可移动天线（MA）是一项通过实现天线局部移动以追求更好信道条件从而显著提升通信性能的新兴技术。对于MA系统而言，获取发射端（Tx）与接收端（Rx）区域间的完整信道状态信息（CSI）是发挥其性能优势的关键问题。本文通过利用多径场响应信道结构，提出了一种适用于MA系统的通用信道估计框架。具体而言，基于Tx-MA与Rx-MA在指定位置上的多次信道测量，我们采用压缩感知方法联合估计多径分量（MPCs）的离开角（AoDs）、到达角（AoAs）及其复系数。在该框架下，Tx-MA与Rx-MA的测量位置从根本上决定了压缩感知的测量矩阵，并从傅里叶变换角度分析了该矩阵的互相关性。此外，本文给出了两种MA测量位置判据以保证MPCs的成功恢复，进而提出多种MA测量位置配置方案并比较其性能。最终，综合仿真结果表明，所提框架能够高精度地估计Tx与Rx区域间的完整CSI。