Channel Tracking for Hybrid DigitalAnalog Architecture in mmWave Systems Millimeter wave (mmWave) with its large spectrum bandwidth is an attractive technology to achieve high date rate, high security and so on. However, it is always difficult to obtain channel state information (CSI) since the mmWave signals undergo large attenuation. This paper proposes a channel tracking algorithm for mmWave multiple input multipleoutput (MIMO) systems, where hybrid precoder and combiner are employed by the transmitter and the receiver, respectively. The algorithm uses extended Kalman filter (EKF) to track the CSI and updates the hybrid combiner to improve tracking accuracy further. Simulation results prove that the proposed algorithm has lower tracking error compared to prior work.

Multiuser mmWave MIMO Channel Estimation with Hybrid Beamforming over Frequency Selective Fading Channels In multiuser millimeter wave (mmWave) multiple input multiple output (MIMO) systems, obtaining accurate informationknowledge regarding the channel state is crucial to achieving multiuser interference cancellation and reliable beamforming (BF)xe2x80x93to compensate for severe path loss. This knowledge is nonetheless very challenging to acquire in practice since large antenna arrays experience a low signaltonoise ratio (SNR) before BF. In this paper, a multiuser channel estimation (CE) scheme namely generalizedblock compressed sampling matching pursuit (GBCoSaMP), is proposed for multiuser mmWave MIMO systems over frequency selective fading channels. This scheme exploits the clusterstructured sparsity in the angular and delay domain of mmWave channels determined by the actual spatial frequencies of each path. As the corresponding spatial frequencies of multiuser mmWave MIMO systems with Hybrid BF often fall between the discrete Fourier transform (DFT) bins due to the continuous Angle of Arrival (AoA)Angle of Departure (AoD), the proposed GBCoSaMP algorithm can address the resulting power leakage problem. Simulation results show that the proposed algorithm is effective and offer a better CE performance in terms of MSE when compared to the generalized block orthogonal matching pursuit (GBOMP) algorithm that does not possess a pruning step.