Robust Analog Precoding Designs for Millimeter Wave MIMO Transceivers
Authors: Pengfei Xia, Robert W. Heath, Jr., N. Gonzalez Prelcic
Proc. of the 20th International ITG Workshop on Smart Antennas (WSA), pp. 1-8, Munich, Germany, March 9-11, 2016.
Millimeter wave communication provides high data rates thanks to large arrays at the transmitter and receiver, coupled with large bandwidth channels. Exploiting the arrays is challenging due to the need to configure precoding at the transmitter based on the large frequency selective channel. In this paper we exploit the power iteration principle and propose a robust analog precoding training algorithm that can be applied in both frequency division duplex transmission (FDD) systems and time division duplex transmission (TDD) systems with or without RF calibration. We further analyze the convergence of the proposed algorithm and show how it converges to the singular value decomposition optimality exponentially. We propose null space projection on top of the power iteration to form multiple orthogonal beams at the transmitter and receiver. Strongest tap selection with proper energy pruning is used to collect as much precoding gain as possible from a frequency selective fading channel. The exponential effective SINR mapping performance is evaluated and demonstrates that the overall approach works effectively. Numerical simulation results demonstrate algorithm robustness and the algorithm works effectively not only for the simplified millimeter wave directional channels, but also for more general rich scattering channels.