Channel estimation and training design for hybrid multi-carrier MmWave massive MIMO systems: The beamspace ESPRIT approach

In this paper, we study the channel estimation problem for a cyclic prefix OFDM (CP-OFDM) based millimeter wave (mmWave) hybrid analog-digital MIMO system, where the analog processing is achieved using only phase shift networks. A three-dimensional (3-D) Standard ESPRIT in discrete Fourier transform (DFT) beamspace approach is developed to estimate the unknown frequency-selective channel. The required training protocol, analog precoding and decoding matrices, as well as pilot patterns are also discussed. Simulation results show that the proposed 3-D Standard ESPRIT in DFT beamspace based channel estimation algorithm provides accurate channel estimates when there is a sufficient number of snapshots.