Method for transmitting and receiving channel state information in multi-antenna wireless communication system, and apparatus therefor

A user equipment (UE) for reporting channel state information (CSI) in a multi-antenna wireless communication system, the UE comprising:

• a transceiver configured to transmit and receive a radio signal;
• and
• a processor configured to control the transceiver,
• wherein the processor;
• receives a channel state information reference signal (CSI-RS) on x multiple antenna ports from a base station, where x is a natural number,
• selects y multi-antenna ports among the x multi-antenna ports, where y is a natural number, and
• reports to the base station a precoding matrix indicator (PMI) indicating a precoding matrix selected from a codebook for the y multi-antenna ports,
• wherein the x multi-antenna ports are grouped into a first antenna port group and a second antenna port group in units of the y multi-antenna ports,
• wherein the precoding matrix is selected based on a weighted summation of a first channel measured based on the CSI-RS transmitted on the antenna port in the first antenna port group and a second channel measured based on the CSI-RS transmitted on the antenna port in the second antenna port group, and
• wherein the precoding matrix is similarly applied to the first antenna port group and the second antenna port group.