Multi-Stage Iterative Antenna Training for Millimeter Wave Communications

We study 60 GHz millimeter wave communication systems employing SVD based transmit precoding and receive combining, and propose a multi-stage iterative method in training the antenna coefficients. The antenna training is carried out in multiple stages one after another, while each stage features an iterative process based on the power iteration principle. Null space projection is used as an enabling step for iterative training in inner stages. The proposed training method is especially efficient for systems with a much smaller number of RF chains relative to the number of antennas on both transmitter and receiver sides.