A two time slot beam training scheme for massive MIMO systems

Abstract

In future communication systems, in order to improve the channel capacity, high frequency communication (i.e. mmWave communication / THz communication) has drawn a lot of attention. The high frequency signals suffer from a severe path loss. Fortunately, massive MIMO has been proposed to realize directional beam with a high array gain to compensate for the high path loss. In order to realize accurate beamforming, the Channel State Information (CSI) is of vital importance. One traditional method of acquiring the CSI is beam training, where the whole space is searched by a series of pre-designed codewords in the codebook, and the codeword with the maximum received power is selected as the direction of the users. However, the performance of this beam training method is limited to the angle resolution of the codewords, and the beam training overhead will increase with the increment of antenna numbers. In this paper, we propose a novel beam training scheme, which can finish the beam training in only two time slots, and the accuracy of the proposed beam training scheme is unrelated to the angle-resolution of the codewords. Simulation results show that the proposed method can reach the near-optimal beam training performance with a very low beam training overhead.