Low-complexity direction estimation techniques for fast beamforming training in millimeter wave multiantenna systems

This paper explores a novel approach for beamforming (BF) training in millimeter wave (mmWave) multiantenna communication systems. The contribution of this paper is in the following aspects: i) This paper proposes a fast BF training procedure building on the novel concept of beamcoding for the estimation of the optimal direction of arrival (DoA) and direction of departure (DoD). Briefly, the beamcoding scheme facilitates the identification of DoA/DoD at the receiver/transmitter based on a set of orthogonal codes. ii) Building on the properties of a special class of orthogonal codes called constant amplitude zero autocorrelation(CAZAC) sequences, this paper proposes a low-complexity implementation of beamcoding procedure to facilitate BF training. We emphasize that the proposed beamcoding schemes can be implemented at the transmitter/receiver with the help of only a single radio frequency (RF) chain with a set of analog phase shifters. Notably, the proposed method is not restricted to just mmWave communication systems, and can be applied to any generic system involving multiantenna transceivers. Simulation results are presented to demonstrate the efficacy of our proposed idea.