A High-Efficiency Beam Sweeping Algorithm for DOA Estimation in the Hybrid Analog-Digital Structure

Abstract

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.