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

Abstract

The present disclosure relates to a method, performed by a user equipment (UE), for reporting channel state information (CSI) in a wireless communication system and an apparatus therefor. According to the present disclosure, the UE receives a channel state information reference signal (CSI-RS) from a base station through a multiple antenna port; and reports the CSI to the base station, wherein the CSI includes a precoding matrix indicator for a codebook generated by linear combination, wherein the codebook is generated based on a specific parameter set, and wherein the specific parameter set is differently set/applied based on at least one of a rank value or at least one layer index of a specific rank.

What is claimed is: 
     
         1 . A method, by a user equipment (UE), of reporting channel state information (CSI) in a wireless communication system, the method comprising:
 receiving, from a base station, configuration information related to a codebook configuration,   wherein a plurality of codebook parameter configurations for a parameter set are pre-defined,   wherein for each of the pre-defined plurality of codebook parameter configurations, a specific parameter of the parameter set is separately configured (i) for rank 1 and rank 2 and (ii) for rank 3 and rank 4, respectively, and   wherein a specific codebook parameter configuration is configured among the pre-defined plurality of codebook parameter configurations;   receiving, from the base station, a channel state information reference signal (CSI-RS); and   reporting, to the base station, the CSI based on the CSI-RS,   wherein the CSI includes a precoding matrix indicator (PMI) based on a codebook configured based on the specific codebook parameter configuration.   
     
     
         2 . The method of  claim 1 ,
 wherein the parameter set includes (i) a parameter for a number of beams to be linearly combined and (ii) a parameter related to the subband PMI.   
     
     
         3 . The method of  claim 2 ,
 wherein a payload of the CSI is determined based on (i) the parameter for the number of the beams to be linearly combined and (ii) the parameter related to the subband PMI.   
     
     
         4 . The method of  claim 1 , further comprising:
 receiving, from the base station, information for configuring specific codebook parameter configuration.   
     
     
         5 . The method of  claim 2 , wherein the separately configured specific parameter (i) for the rank 1 and the rank 2 and (ii) for the rank 3 and the rank 4, respectively, is the parameter related to the subband PMI. 
     
     
         6 . The method of  claim 2 , wherein a maximum number of the beams to be linearly combined for the rank 1 and the rank 2 is greater than a maximum number of the beams to be linearly combined for the rank 3 and the rank 4. 
     
     
         7 . A user equipment (UE) for transmitting channel state information (CSI) in a wireless communication system, the UE comprising:
 a RF (Radio Frequency) module including a transceiver for transmitting and receiving a radio signal; and   a processor for controlling the RF module, wherein the processor,   receiving, from a base station, configuration information related to a codebook configuration,   wherein a plurality of codebook parameter configurations for a parameter set are pre-defined,   wherein for each of the pre-defined plurality of codebook parameter configurations, a specific parameter of the parameter set is separately configured (i) for rank 1 and rank 2 and (ii) for rank 3 and rank 4, respectively, and   wherein a specific codebook parameter configuration is configured among the pre-defined plurality of codebook parameter configurations;   receiving, from the base station, a channel state information reference signal (CSI-RS); and   reporting, to the base station, the CSI based on the CSI-RS,   wherein the CSI includes a precoding matrix indicator (PMI) based on a codebook configured based on the specific codebook parameter configuration.   
     
     
         8 . A base station for receiving channel state information (CSI) in a wireless communication system, the base station comprising:
 a RF (Radio Frequency) module including a transceiver for transmitting and receiving a radio signal; and   a processor for controlling the RF module, wherein the processor,   transmitting, to a user equipment (UE), configuration information related to a codebook configuration,   wherein a plurality of codebook parameter configurations for a parameter set are pre-defined,   wherein for each of the pre-defined plurality of codebook parameter configurations, a specific parameter of the parameter set is separately configured (i) for rank 1 and rank 2 and (ii) for rank 3 and rank 4, respectively, and   wherein a specific codebook parameter configuration is configured among the pre-defined plurality of codebook parameter configurations;   transmitting, from the UE, a channel state information reference signal (CSI-RS); and   receiving, from the UE, the CSI based on the CSI-RS,   wherein the CSI includes a precoding matrix indicator (PMI) based on a codebook configured based on the specific codebook parameter configuration.