Method for transmitting and receiving channel state information in wireless communication system, and apparatus therefor
Disclosed are a method for transmitting and receiving channel state information in a wireless communication system and an apparatus therefor. Specifically, a method for transmitting, by a terminal, channel state information (CSI) in a wireless communication system comprises the steps of: receiving a CSI process setting from a base station; and reporting, to the base station, CSI corresponding to a CSI process set by the CSI process setting, wherein when the CSI process is set to a beamformed CSI-reference signal (CSI-RS) type, and the CSI process is associated with a single CSI-RS resource, a codebook used for deriving the CSI may be indicated by the CSI process setting.
1. A method for transmitting channel state information (CSI) by a user equipment (UE) in a wireless communication system, the method comprising:
receiving, from a base station (B S), configuration information for a CSI process,
wherein based on that i) the CSI process is associated with a beamformed CSI-reference signal (CSI-RS) and ii) a single CSI-RS resource is configured for the CSI process, the configuration information includes information for indicating whether a codebook for a beam selection and co-phasing is configured to be used for deriving a CSI for the CSI process or not;
based on configurations that i) the CSI process is associated with the beamformed CSI-RS, ii) the single CSI-RS resource is configured for the CSI process and iii) the codebook for the beam selection and co-phasing is configured to be used for deriving the CSI based on the information, obtaining the CSI for the CSI process using the codebook for the beam selection and co-phasing; and
transmitting, to the BS, the CSI for the CSI process.
2. The method of claim 1 , wherein the CSI for the CSI process includes a single index for specifying a precoding matrix in the codebook as a Precoding Matrix Indicator (PMI), based on the codebook being configured to be used for deriving the CSI based on the information.
3. The method of claim 1 , wherein the CSI for the CSI process includes a pair of a first index for selecting a set of precoding matrixes from another codebook and a second index for specifying a precoding matrix in the set of precoding matrixes specified by the first index as a Precoding Matrix Indicator (PMI), based on the codebook being configured not to be used for deriving the CSI based on the information.
4. The method of claim 1 , wherein the codebook is not used for deriving the CSI, based on a CSI measurement restriction (MR) being configured to the CSI process.
5. The method of claim 1 , wherein the codebook is used for deriving the CSI, based on a CSI measurement restriction (MR) being skipped to be configured to the CSI process.
6. The method of claim 1 , wherein the configuration information includes measurement restriction (MR) indication information for whether a CSI MR is configured.
7. The method of claim 1 , wherein, based on the CSI process including a first CSI-RS configuration associated with more than one CSI-RS resources of a beamformed CSI-RS type and a second CSI-RS configuration associated with one CSI-RS resource of the beamformed CSI-RS type,
the codebook is not used for a CSI-RS resource of the more than one CSI-RS resources configured in the first CSI-RS configuration, and the codebook is used for the one CSI-RS resource in the second CSI-RS configuration.
8. A user equipment (UE) transmitting channel state information (CSI) in a wireless communication system, the UE comprising:
a radio frequency (RF) unit for transmitting and receiving a radio signal; and
a processor for controlling the RF unit,
wherein the processor is configured to perform operations comprising:
receiving, from a base station (BS), configuration information for a CSI process,
wherein based on that i) the CSI process is associated with a beamformed CSI-reference signal (CSI-RS) and ii) a single CSI-RS resource is configured for the CSI process, the configuration information includes information for indicating whether a codebook for a beam selection and co-phasing is configured to be used for deriving a CSI for the CSI process or not;
based on configurations that i) the CSI process is associated with the beamformed CSI-RS, ii) the single CSI-RS resource is configured for the CSI process and iii) the codebook for the beam selection and co-phasing is configured to be used for deriving the CSI based on the information, obtaining the CSI for the CSI process using the codebook for the beam selection and co-phasing; and
transmitting, to the BS, the CSI for the CSI process.
9. The UE of claim 8 , wherein a single index for specifying a precoding matrix in the codebook is reported to the BS as a Precoding Matrix Indicator (PMI), based on the codebook being configured to be used for deriving the CSI based on the information.
10. The UE of claim 8 , wherein a pair of a first index for selecting a set of precoding matrixes from another codebook and a second index for specifying a precoding matrix in the set of precoding matrixes specified by the first index is reported to the BS as a Precoding Matrix Indicator (PMI), based on the codebook being configured not to be used for deriving the CSI based on the information.