Three Dimensional Beamforming and Limited Feedback Precoding for Future LTE-Advanced Systems with Large-scale Antenna Arrays

Very large multiple input multiple output (MIMO) system (referred to as massive MIMO) is currently investigated as a novel technology to enhance system throughput for future cellular systems. In this paper, we study a practical implementation of massive MIMO technology in LTE-Advanced systems. Firstly, two three dimensional(3D) dynamic beamforming schemes are proposed to realize full spatial resolution of the elevation as well as the traditional azimuth domain. These schemes are implemented through combining a couple of precoder matrix indictor (horizontal PMI and vertical PMI) during the channel state information (CSI) feedback stage. Furthermore, we also propose a limited feedback precoding algorithm named PMI-based regularized zero-forcing precoding (P-RZF) to achieve multi-user MIMO (MU-MIMO). System level simulation is performed to evaluate the proposed schemes.