Robust beam management scheme based on simple 2-D DOA estimation

In this paper, we consider a millimeter wave (mmWave) multiple-input multiple-output (MIMO) communication system with hybrid beamforming architecture. To search the optimal beam pair, the beam sweeping algorithm is complex and time-consuming in the case of initial access and beam switching. With the aim of improving the robustness, we propose a novel beam management scheme to quickly determine the optimal beam and switch to the suboptimal beam. To implement the beam management scheme, we design a simple 2-dimensional (2-D) direction-of-arrival (DOA) estimation strategy using limited radio frequency (RF) chains in the hybrid array. Numerical results show that the proposed scheme can obtain an excellent achievable rate which is the same as that of the MIMO system employed optimal design. Further, the proposed beam management scheme greatly reduces the time cost of the beam selection.