Method and apparatus for reporting channel state information in wireless communication system

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

• a receiver;
• a transmitter;
• and
• a processor,
• wherein the processor is configured to:
• control the receiver to receive a channel state information-reference signal (CSI-RS) based on CSI-RS configuration information that is provided by a base station, and
• control the transmitter to report to the base station the CSI generated using the CSI-RS,
• the CSI includes precoding information selected from a predetermined codebook,
• elements of the predetermined codebook are configured based on a precoding vector W,
• the precoding vector W is
• W
• =
• [
• W
• 
• 
• 1
• aW
• 
• 
• 2
• ]
• ,
• W1 is a precoding vector applied to a first domain antenna group having a 2D antenna structure,
• W2 is a precoding vector applied to a second domain antenna group having the 2D antenna structure, and
• “a” is a value representing phase difference between the first domain antenna group and the second domain antenna group.

A method for receiving channel state information (CSI) from a base station of a wireless communication system, the method comprising:

• providing a user equipment with channel state information-reference signal (CSI-RS) configuration information and transmitting a CSI-RS to the user equipment based on the CSI-RS configuration information;
• and
• receiving the CSI, which is generated by the user equipment using the CSI-RS, from the user equipment,
• wherein the CSI includes precoding information selected from a predetermined codebook,
• elements of the predetermined codebook are configured based on a precoding vector W,
• the precoding vector W is
• W
• =
• [
• W
• 
• 
• 1
• aW
• 
• 
• 2
• ]
• ,
• W1 is a precoding vector applied to a first domain antenna group having a 2D antenna structure,
• W2 is a precoding vector applied to a second domain antenna group having the 2D antenna structure, and
• “a” is a value representing phase difference between the first domain antenna group and the second domain antenna group.

A base station for receiving channel state information (CSI) in a wireless communication system, the base station comprising:

• a receiver;
• a transmitter;
• and
• a processor,
• wherein the processor is configured to:
• provide a user equipment with channel state information-reference signal (CSI-RS) configuration information, and
• control the transmitter to transmit a CSI-RS to the user equipment based on the CSI-RS configuration information, and
• control the receiver to receive the CSI, which is generated by the user equipment using the CSI-RS, from the user equipment,
• the CSI includes precoding information selected from a predetermined codebook,
• elements of the predetermined codebook are configured based on a precoding vector W,
• the precoding vector W is
• W
• =
• [
• W
• 
• 
• 1
• aW
• 
• 
• 2
• ]
• ,
• W1 is a precoding vector applied to a first domain antenna group having a 2D antenna structure,
• W2 is a precoding vector applied to a second domain antenna group having the 2D antenna structure, and
• “a” is a value representing phase difference between the first domain antenna group and the second domain antenna group.