Patent ID: 9391682
Filing Date: 2016-07-12
CPC Classification: H04B

Claim Text:
1. A user equipment comprising: a transmission and reception unit configured to communicate a radio signal with a base station in accordance with MIMO (Multiple Input Multiple Output) transmission; a codebook storage unit configured to store predefined codebooks to specify precoding matrices for use in the MIMO transmission, wherein the codebooks are arranged to represent phase information and gain information; a channel measurement unit configured to measure channel conditions based on reference signals transmitted from multiple antennas in the base station; and a codebook selection unit configured to select a codebook to be indicated to the base station from the stored codebooks based on the measured channel conditions and instruct the transmission and reception unit to indicate feedback information to the base station, wherein the feedback information includes a codebook index for identifying the selected codebook, wherein the feedback information identifies a first matrix W