Beamspace U-ESPRIT DOA Estimation Algorithm of Coherently Distributed Sources in Massive MIMO Systems

The coherently distributed sources model is more suitable to support the DOA estimation for massive Multiple-Input Multiple-Output (MIMO) systems. Since a large number of antennas brings unbearable computing burden of the DOA estimation, we propose a low-complexity DOA estimation algorithm for coherently distributed sources by utilizing unitary ESPRIT in beamspace. Specifically, by choosing fewer beams in two-dimensional beamspace for DOA estimation, the dimension of the output vector decreases so that the complexity is greatly reduced. In addition, the U-ESPRIT algorithm is utilized in beamspace and the azimuth angle and the elevation angle are automatically coupled with low complexity. Moreover, the proof of rotation invariance and the analysis of complexity guarantee the feasibility of the proposed algorithm. Simulation results demonstrate the effectiveness and robustness of the proposed algorithm for massive MIMO systems.