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

1. A method for a user equipment to report channel state information (CSI) in a multi-antenna wireless communication system, the method comprising:

receiving first configuration information about a non-precoded first channel state information-reference signal (CSI-RS) configuration from a base station;

receiving first CSI-RS from the base station;

reporting, to the base station, first CSI generated based on the first CSI-RS; and

reporting, to the base station, codebook configuration information about a codebook configuration which is a basis for generating the first CSI, wherein the codebook configuration information represents a determined codebook configuration among a plurality of codebook configurations, the determined codebook configuration being related to a largest number of preferred beams with respect to a channel quality,

wherein the first CSI includes a plurality of precoding matrix indicators (PMIs) derived based on the codebook configuration,

wherein the plurality of PMIs includes at least one PMI having best performance and at least one PMI having worst performance, and

wherein the at least one PMI having worst performance is related to MU (Multi-User) scheduling.

2. The method of claim 1 , wherein the first configuration information comprises antenna port layout information which is a basis for generating the first CSI and oversampling factor information applied to an antenna layout and is transmitted to the user equipment through higher layer signaling.

3. The method of claim 2 , wherein:

the plurality of codebook configurations is previously defined to have different beam patterns.

4. The method of claim 3 , wherein the codebook configuration information is reported to the base station independently of the first CSI or is joint-encoded with the first CSI and reported to the base station.

5. The method of claim 4 , wherein the plurality of PMIs is selected as many as a preset number determined based on at least one of a channel quality indicator (CQI) or a signal-to-interference-plus-noise ratio (SINR) and is reported to the base station.

6. The method of claim 5 , wherein based on two identical beams overlapping between beam groups specified by neighboring PMIs according to the codebook configuration, the plurality of PMIs is restricted to represent only a specific number related to a non-overlapping beam group.

7. The method of claim 6 , wherein:

the plurality of PMIs is derived based on the codebook configuration in a state in which a number of transmission layers is assumed to be “1”, and

a rank indicator (RI) indicating the number of transmission layers is not reported to the base station as the first CSI.

8. The method of claim 6 , wherein at least one rank indicator (RI) associated with at least one PMI of the plurality of PMIs is reported to the base station as the first CSI.

9. The method of claim 8 , wherein when the at least one RI is reported to the base station as the first CSI, one RI associated with a PMI having best performance or a PMI having worst performance among the plurality of PMIs, one RI associated with the plurality of PMIs in common, or a plurality of RIs associated with the plurality of PMIs, respectively, is reported.

10. The method of claim 5 , further comprising:

receiving, from the base station, second configuration information for a second CSI report based on a beamformed second CSI-RS; and

reporting, to the base station, second CSI generated based on the second configuration information.

11. The method of claim 10 , wherein the first configuration information and the second configuration information are received by the user equipment through configuration information for a single CSI process.

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

a radio frequency (RF) unit for transmitting and receiving radio signals; and

a processor controlling the RF unit,

wherein the processor is configured to:

receive first configuration information about a non-precoded first channel state information-reference signal (CSI-RS) configuration from a base station;

receive first CSI-RS from the base station;

report, to the base station, first CSI generated based on the first CSI-RS; and

report, to the base station, codebook configuration information about a codebook configuration which is a basis for generating the first CSI,

wherein the codebook configuration information represents a determined codebook configuration among a plurality of codebook configurations, the determined codebook configuration being related to a largest number of preferred beams with respect to a channel quality,

wherein the first CSI includes a plurality of precoding matrix indicators (PMIs) derived based on the codebook configuration,

wherein the plurality of PMIs includes at least one PMI having best performance and at least one PMI having worst performance, and

wherein the at least one PMI having worst performance is related to MU (Multi-User) scheduling.

13. The user equipment of claim 12 , wherein:

the plurality of codebook configurations is previously defined to have different beam patterns.

14. The user equipment of claim 13 , wherein the codebook configuration information is reported to the base station independently of the CSI or is joint-encoded with the CSI and reported to the base station.