A Codebook-Based Concept for Hybrid CSI Feedback in FDD Massive MIMO Systems

Abstract

In this paper we discuss the pros and cons of nonprecoded and beamformed Channel State Information (CSI) downlink (DL) reference signal schemes for Frequency Division Duplex (FDD) massive MIMO systems. We propose a hybrid mode of operation between the two, factorizing the antenna ports into a set of slow and fast ports with different update rates using a codebook with factorized precoders designed for a dualpolarized Uniform Planar Array (UPA). We show with simulation results that the proposed hybrid CSI feedback scheme can increase both average and 5th percentile spectral efficiency compared to the non-precoded CSI reference signal scheme. Compared to the beamformed CSI reference signal scheme, it can significantly increase the 5th percentile spectral efficiency with only a small loss in average spectral efficiency. Index Terms – hybrid CSI feedback, beamforming, codebook, closed-loop feedback

DOI: 10.1109/VTCSpring.2016.7504056

8 Figures and Tables

Cite this paper

@inproceedings{Faxer2016ACC, title={A Codebook-Based Concept for Hybrid CSI Feedback in FDD Massive MIMO Systems}, author={Sebastian Faxer and Svante Bergman and Niklas Wernersson}, booktitle={VTC Spring}, year={2016} }