For frequency-division-duplexing (FDD) systems, channel state information (CSI) should be fed back from the user terminal to the base station. This feedback overhead becomes problematic as the number of antennas grows. To alleviate this issue, we propose a flexible CSI compression method using variational autoencoder (VAE) with an entropy bottleneck structure, which can support multi-rate and variable-length operation. Numerical study confirms that the proposed method outperforms the existing CSI compression techniques in terms of normalized mean squared error.

翻译：针对频分双工（FDD）系统，信道状态信息（CSI）需从用户终端反馈至基站。随着天线数量增加，此反馈开销问题日益凸显。为缓解该问题，我们提出一种基于变分自编码器（VAE）并采用熵瓶颈结构的灵活CSI压缩方法，该方法可支持多速率与可变长度操作。数值研究证实，所提方法在归一化均方误差指标上优于现有CSI压缩技术。