This letter rethinks traditional precoding in multi-user wireless communications with movable antennas (MAs). Utilizing MAs for optimal antenna positioning, we introduce a sparse optimization (SO)-based approach focusing on regularized zero-forcing (RZF). This framework targets the optimization of antenna positions and the precoding matrix to minimize inter-user interference and transmit power. We propose an off-grid regularized least squares-based orthogonal matching pursuit (RLS-OMP) method for this purpose. Moreover, we provide deeper insights into antenna position optimization using RLS-OMP, viewed from a subspace projection angle. Overall, our proposed flexible precoding scheme demonstrates a sum rate that exceeds more than twice that of fixed antenna positions.

翻译：本文重新思考了采用可移动天线（MA）的多用户无线通信中的传统预编码技术。通过利用MA实现最优天线定位，我们提出了一种基于稀疏优化（SO）的方法，重点研究正则化迫零（RZF）技术。该框架旨在优化天线位置与预编码矩阵，以最小化用户间干扰和发射功率。为此，我们提出了一种基于离网格正则化最小二乘的正交匹配追踪（RLS-OMP）方法。此外，我们从子空间投影的角度，对基于RLS-OMP的天线位置优化提供了更深入的理论见解。总体而言，所提出的灵活预编码方案的信道容量总和可达到固定天线位置方案的两倍以上。