A Novel Channel Estimation Scheme for Frequency-Selective mmWave Massive MIMO Systems

In this paper, a two-stage channel estimation scheme is presented for frequency-selective millimeter wave (mmWave) massive multiple-input multiple-output (MIMO) systems with hybrid precoding. Specifically, at the first stage, likelihood function with respective to the channel angle of departure (AoD) and angle of arrival (AoA) are maximized by the deterministic maximum likelihood (DML) estimator to obtain a coarse channel estimate. At the second stage, a space-alternating generalized expectation-maximization (SAGE) based algorithm is proposed to refine the channel parameters. In addition, an angle paring scheme is proposed to paired the AoA and AoD. Simulation results show the better performance of the proposed method.