Hybrid Beamforming Design for Massive MIMO Systems with Limited CSI Feedback

Abstract

In this study, we investigate a limited channel state information (CSI) feedback scheme to allow the implementation of hybrid beamforming based on joint spatial division and multiplexing (JSDM). We propose the usage of beam sweeping to provide channel measurements that are used to feed a CSI report scheme that allows an adequate estimation of the channel characteristics with short pilot sequences and very few precoder matrix indicators (PMIs), thus significantly reducing the required signaling. The hybrid beamforming scheme exploits successfully the provided CSI and achieves satisfactory total data rates in comparison to the full CSI report approach, as shown in our simulation results.