An efficient beam and channel acquisition and tracking scheme is developed under a reconfigurable hybrid beamforming (R-HBF) architecture for wideband millimeter wave (mmWave) multiple input multiple output (MIMO) systems. Under such an R-HBF, a hierarchical multi-resolution beam scanning and space-frequency compressive sensing method is proposed to achieve fast beam and channel acquisitions in mmWave MIMO orthogonal frequency division multiplexing (OFDM) systems. With the initial frequency-domain beam space channel estimates, Kalman-based algorithms are further developed to track the transmit and receive beamforming directions and the channel coefficients of the sparse propagation paths in mmWave mobile channels. Simulations show that the proposed method can greatly reduce the beam training time, and that the channel capacity evaluated with the estimated channels is only  2 dB inferior to the one with ideal channels. Moreover, the beam selection error rates are less than 10-3 in typical urban mmWave mobile channels and traveling speeds even if the transmit power is only 10 dBm. The related research papers are listed as follows:

• S.-H. Wu and G.-Y. Lu, “Compressive Beam and Channel Tracking with Reconfigurable Hybrid Beamforming in mmWave MIMO OFDM Systems,” in IEEE Transactions on Wireless Communications, vol. 22, no. 2, pp. 1145-1160, Feb. 2023. (Link)
• S.-H. Wu, L.-K. Chiu, and J.-W. Wang, "Reconfigurable hybrid beamforming for dual-polarized mmWave MIMO channels: Stochastic channel modeling and architectural adaptation methods,” in IEEE Transactions on Communications, vol. 66, no. 2, pp. 741-755, Feb. 2018. (Link)
• S.-H. Wu, L.-K. Chiu, K.-Y. Lin,  and T.-H. Chang, "Robust hybrid beamforming with phased antenna arrays for downlink SDMA in indoor 60GHz channels,” in IEEE Transactions on Wireless Communications, vol. 12, no. 9, pp. 4542-4557, Sept. 2013. (Link)