CROSS-REFERENCE TO RELATED APPLICATIONS

This application is the National Stage filing under 35 U.S.C. 371 of International Application No. PCT/KR2019/003905, filed on Apr. 2, 2019, which claims benefit of KR Application No. 10-2018-0037963, filed on Apr. 2, 2018, the contents of which are all hereby incorporated by reference herein in their entirety.

TECHNICAL FIELD

The present disclosure relates to a wireless communication system, and more particularly to a method for transmitting and receiving channel state information and a device supporting the same.

BACKGROUND ART

Mobile communication systems have been generally developed to provide voice services while guaranteeing user mobility. Such mobile communication systems have gradually expanded their coverage from voice services through data services up to high-speed data services. However, as current mobile communication systems suffer resource shortages and users demand even higher-speed services, development of more advanced mobile communication systems is needed.

The requirements of the next-generation mobile communication system may include supporting huge data traffic, a remarkable increase in the transfer rate of each user, the accommodation of a significantly increased number of connection devices, very low end-to-end latency, and high energy efficiency. To this end, various techniques, such as small cell enhancement, dual connectivity, massive multiple input multiple output (MIMO), in-band full duplex, non-orthogonal multiple access (NOMA), supporting super-wide band, and device networking, have been researched.

DISCLOSURE

Technical Problem

The present disclosure provides a method for transmitting and receiving channel state information.

The present disclosure also provides a method for grouping a plurality of user equipments using angular information.

The technical problems to be solved by the present disclosure are not limited by the above-mentioned technical problems, and other technical problems which are not mentioned above can be clearly understood from the following description by those skilled in the art to which the present disclosure pertains.

Technical Solution

In one aspect, there is provided a method for a base station to receive channel state information in a wireless communication system.

More specifically, the method comprises transmitting, to a plurality of user equipments (UEs), CSI-RS for calculating the channel state information; receiving, from the plurality of UEs, angular information related to a channel state between the base station and the plurality of UEs based on the CSI-RS; transmitting, to the plurality of UEs, configuration information for calculating the channel state based on the angular information, the configuration information including information determining an operation mode of the plurality of UEs; and receiving, from the plurality of UEs, the channel state information calculated based on the operation mode.

The angular information includes at least one of a signal direction, an angular spread, a spatial rotation parameter, a number of beams of a transformation matrix, and an index of the transformation matrix.

The angular information is received in one of periodic, aperiodic, and semi-persistent transmission types.

The method further comprises, before transmitting to the plurality of UEs the configuration information for calculating the channel state based on the angular information, grouping the plurality of UEs based on the angular information.

The plurality of grouped UEs is configured to be divided into a representative UE and a sub-UE.

The representative UE and the sub-UE are determined based on unique indexes of the plurality of grouped UEs, or determined by a pre-configured criterion.

The representative UE and the sub-UE are determined based on the operation mode. A UE is configured as the representative UE when the operation mode is ‘ON’, and a UE is configured as the sub-UE when the operation mode is ‘OFF’.

Receiving the channel state information calculated based on the operation mode comprises receiving only the channel state information of a UE configured as the representative UE.

In another aspect, there is provided a method for a user equipment (UE) to transmit channel state information in a wireless communication system, the method comprising receiving, from a base station, CSI-RS for calculating the channel state information; transmitting, to the base station, angular information related to a channel state between the base station and the UE based on the received CSI-RS; receiving, from the base station, configuration information for calculating a channel state based on the angular information, the configuration information including information determining an operation mode of the UE; and transmitting, to the base station, the channel state information calculated based on the operation mode.

The UE is configured as a representative UE when the operation mode is ‘ON’, and the UE is configured as a sub-UE when the operation mode is ‘OFF’.

The method further comprises, when the operation mode is ‘ON’, transmitting, to the base station, at least one of a number of beams of a transformation matrix, a beam index of the transformation matrix, a spatial rotation parameter, and a coefficient of a channel to which the spatial rotation parameter is applied.

Transmitting the channel state information calculated based on the operation mode comprises transmitting the channel state information of the UE only when the UE is configured as the representative UE.

In another aspect, there is provided a base station receiving channel state information in a wireless communication system, the base station comprising a radio frequency (RF) module configured to transmit and receive a radio signal; and a processor functionally connected to the RF module, wherein the processor is configured to transmit, to a plurality of user equipments (UEs), CSI-RS for measuring the channel state information; receive, from the plurality of UEs, angular information related to a channel state between the base station and the plurality of UEs based on the CSI-RS; transmit, to the plurality of UEs, configuration information for measuring the channel state based on the angular information, the configuration information including information determining an operation mode of the plurality of UEs; and receive, from the plurality of UEs, the channel state information calculated based on the operation mode.

The processor is configured to group the plurality of UEs based on the angular information.

The plurality of grouped UEs is configured to be divided into a representative UE and a sub-UE. The processor is configured to receive only the channel state information of a UE configured as the representative UE.

Advantageous Effects

The present disclosure has an effect capable of efficiently transmitting and receiving channel state information by providing a method for transmitting and receiving the channel state information.

The present disclosure also has an effect capable of efficiently transmitting and receiving channel state information by providing a method for grouping UEs.

Effects obtainable from the present disclosure are not limited by the effects mentioned above, and other effects which are not mentioned above can be clearly understood from the following description by those skilled in the art to which the present disclosure pertains.

