The spatial covariance matrix, as the core of subspace direction of arrival (DOA) estimation, is unavailable in the hybrid analog-digital structure, which is widely used in large-scale transceivers to reduce the number of radio frequency chains. In previous studies, the beam sweeping algorithm (BSA) has been used for effectively reconstructing the spatial covariance matrix. However, the BSA is not practical owning to the intractable computational cost due to the high-dimensional matrix operations. To address this problem, a high-efficiency BSA (HeBSA) is proposed. The main motivation behind the HeBSA is to avoid the high-dimensional matrix multiplication and inversion. By appropriately adjusting weights connected to antennas, the real-valued spatial covariance matrix can be reconstructed according to low-dimensional matrix multiplication. Then the classical U-root multiple signal classification can be adopted to estimate the DOA angle of each signal. Finally, simulation experiments are conducted to verify the performance of the HeBSA. The results indicate that the HeBSA can achieve DOA estimation performance comparable with that of BSA even at considerably lower computational cost.

中文翻译：

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混合模数结构中DOA估计的高效波束扫描算法

空间协方差矩阵作为子空间到达方向（DOA）估计的核心，在混合模数结构中是不可用的，广泛用于大规模收发器以减少射频链的数量。在以往的研究中，波束扫描算法（BSA）已被用于有效地重建空间协方差矩阵。然而，由于高维矩阵运算，BSA 由于难以处理的计算成本而不实用。为了解决这个问题，提出了一种高效 BSA（HeBSA）。HeBSA 背后的主要动机是避免高维矩阵乘法和求逆。通过适当调整与天线相连的权重，可以根据低维矩阵乘法重构实值空间协方差矩阵。然后可以采用经典的U-root多信号分类来估计每个信号的DOA角。最后，进行仿真实验以验证 HeBSA 的性能。结果表明，即使在相当低的计算成本下，HeBSA 也可以实现与 BSA 相当的 DOA 估计性能。