Method for acquiring downlink channel information and apparatus for acquiring downlink channel information, and network side device

摘要

This application provides a method and an apparatus for obtaining downlink channel information, and a network side device. The method includes: performing precoding weighting on M CSI-RSs of each of N sub-cycles, where each sub-cycle is a quantity of measurement pilot subframes for bearing and transmitting the M CSI-RSs; sending the M weighted CSI-RSs of each sub-cycle to UE; receiving M PMIs and M CQIs that are sent by the UE and that correspond to the M CSI-RSs of each sub-cycle, where the M PMIs and the M CQIs are obtained by the UE by separately measuring the M weighted CSI-RSs based on a set of rank 1 precoding codebooks corresponding to the predetermined antenna quantity; obtaining M signal-to-noise ratios of a downlink channel of the UE according to the M CQIs of each sub-cycle; obtaining M equivalent codebooks according to the M PMIs of each sub-cycle and weights of the precoding weighting; and obtaining a covariance matrix according to the M signal-to-noise ratios of the downlink channel and the M equivalent codebooks.