Method for reporting channel state information in wireless communication system, and device therefor

1. A method of reporting channel state information (CSI) by a terminal in a wireless communication system, the method comprising:

obtaining a CSI measurement by measuring a CSI-RS (reference signal) that is transmitted from a base station through a plurality of panels of the base station, with the plurality of panels;

reporting, to the base station, the CSI that is generated based on the CSI measurement, wherein reporting the CSI comprises: reporting, for the plurality of panels, a first phase parameter for WB (Wideband) among (i) the first phase parameter for WB and (ii) a second phase parameter for SB (Subband),

wherein the first phase parameter for WB and the second phase parameter for SB are used for phase correction between the plurality of panels; and

reporting, for the plurality of panels, a third phase parameter which is used for phase correction between cross polarization antenna ports included in each of the plurality of panels,

wherein values of the third phase parameter applied to each of the plurality of panels are same.

2. The method of claim 1 , wherein the first phase parameter for WB is reported based on QPSK (quadrature phase-shift keying).

3. The method of claim 1 , wherein a number of the plurality of panels is set by higher-layer signaling.

4. The method of claim 1 , wherein the first phase parameter for WB provides a first compensation amount for an overall co-phase, and the second phase parameter for SB provides a second compensation amount for the overall co-phase, in addition to the first compensation amount.

5. The method of claim 1 , the second phase parameter for SB first phase parameter for is reported based on BPSK (binary phase-shift keying).

6. The method of claim 1 , wherein the plurality of panels comprises a first panel and a second panel,

wherein reporting the CSI further comprises: reporting, for the second panel among the plurality of panels, both (i) the first phase parameter for WB and (ii) the second phase parameter for SB, and

wherein the first phase parameter for WB is reported using 2 bits and the second phase parameter for SB is reported using 1 bit.

7. The method of claim 6 , wherein whether to report (i) only the first phase parameter for WB among the first phase parameter for WB and the second phase parameter for SB or (ii) the first phase parameter for WB and the second phase parameter for SB among the first phase parameter for WB and the second phase parameter for SB is set by the higher-layer signalling.

8. The method of claim 6 , wherein the first phase parameter for WB and the second phase parameter for SB are reported in a PMI (Precoding Matrix Index) in the CSI.

9. The method of claim 6 , wherein the first phase parameter for WB and the second phase parameter for SB are reported independently at least for each of the plurality of panels or for each of a plurality of polarizations.

10. The method of claim 6 , wherein each of the first panel and the second panel comprises a plurality of antenna elements, and

wherein the first phase parameter for WB and the second phase parameter for SB provide phase correction for antenna elements between the first panel and the second panel.

11. The method of claim 6 , wherein the second phase parameter for SB is reported for a plurality of subbands, using 1 bit for each of the plurality of subbands.

12. A terminal configured to report channel state information (CSI) in a wireless communication system, the terminal comprising:

a radio frequency (RF) unit;

at least one processor; and

at least one computer memory operably connectable to the at least one processor and storing instructions that, when executed by the at least one processor, perform operations comprising:

obtaining a CSI measurement by measuring a CSI-RS (reference signal) that is transmitted from a base station through a plurality of panels of the base station, with the plurality of panels;

reporting, to the base station, the CSI that is generated based on the CSI measurement, wherein reporting the CSI comprises: reporting, for the plurality of panels, a first phase parameter for WB (Wideband) among (i) the first phase parameter for WB and (ii) a second phase parameter for SB (Subband),

wherein the first phase parameter for WB and the second phase parameter for SB are used for phase correction between the plurality of panels; and

reporting, for the plurality of panels, a third phase parameter which is used for phase correction between cross polarization antenna ports included in each of the plurality of panels,

wherein values of the third phase parameter applied to each of the plurality of panels are same.

13. The terminal of claim 12 , wherein the first phase parameter for WB is reported based on QPSK (quadrature phase-shift keying).

14. The terminal of claim 12 , wherein the first phase parameter for WB provides a first compensation amount for an overall co-phase, and the second phase parameter for SB provides a second compensation amount for the overall co-phase, in addition to the first compensation amount.

15. The terminal of claim 12 , wherein the plurality of panels comprises a first panel and a second panel,

wherein reporting the CSI further comprises: reporting, for the second panel among the plurality of panels, both (i) the first phase parameter for WB (Wideband) and (ii) the second phase parameter for SB (Subband),

wherein the first phase parameter for WB is reported using 2 bits and the second phase parameter for SB is reported using 1 bit.

16. The terminal of claim 15 , wherein each of the first panel and the second panel comprises a plurality of antenna elements, and

wherein the first phase parameter for WB and the second phase parameter for SB provide phase correction for antenna elements between the first panel and the second panel.

17. The terminal of claim 15 , wherein the second phase parameter for SB is reported for a plurality of subbands, using 1 bit for each of the plurality of subbands.