Differential quantization of precoder matrix

Abstract

In an aspect of the disclosure, a method, a computer-readable medium, and an apparatus are provided. The apparatus may be a UE. The UE measures one or more reference signals to determine a channel state on a channel including M delay taps. The UE determines a first precoder matrix for selecting a set of beams from L beams transmitted from the base station on the channel. The UE determines a second precoder matrix for combining the set of beams. The second precoder matrix includes at least two groups of coefficients each including coefficients being normalized based on a respective reference coefficient. Each coefficient corresponds to a respective one beam of the L beams at a particular polarization on a respective one delay tap of the M delay taps. The UE quantizes coefficients of the second precoder. The UE transmits an indication of the second precoder matrix having quantized coefficients.