# US 10,374,664 B2 · Method for reporting channel state in wireless communication system and apparatus therefor

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- Number: US 10,374,664 B2
- Document ID: US10374664B2
- Status: Granted
- Kind: B2
- Application number: 15/773,097
- Filed: 2016-10-31
- Published: 2018-11-15
- Granted: 2019-08-06
- Earliest claimed: 2015-11-03
- Assignees: LG Electronics Inc.
- Applicants: LG Electronics Inc.
- Inventors: Kunil Yum; Jonghyun Park; Kijun Kim
- Web page: https://patentgrep.com/patent/US10374664B2

## CPC

- H04B 7/0626: {Channel coefficients, e.g. channel state information [CSI]}
- H04B 7/0417: Feedback systems
- H04B 7/0621: {Feedback content}
- H04B 7/063: {Parameters other than those covered in groups H04B7/0623 - H04B7/0634, e.g. channel matrix rank or transmit mode selection}
- H04B 7/0643: {Feedback on request}
- H04B 7/0814: {based on current reception conditions, e.g. switching to different antenna when signal level is below threshold}
- H04L 27/2613: {Structure of the reference signals}
- H04B: TRANSMISSION
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)

## Abstract

A method for reporting an aperiodic channel condition in a wireless communication system, according to an embodiment of the present invention, is performed by a terminal. The method comprises the steps of: receiving, from a base station, setting for one or more channel state information (CSI) processes including a plurality of channel state information-reference signals (CSI-RS) resources, wherein precoding is applied to each of the plurality of CSI-RS resources; receiving an aperiodic CSI report request from the base station; and transmitting, to the base station, an aperiodic CSI for a CSI process indicated by the aperiodic CSI report request, wherein, if a certain time has not elapsed after a CSI-RS resource index for the CSI process indicated by the aperiodic CSI report request is reported, the transmitted aperiodic CSI may include a CSI-RS resource index for a CSI process which has not been updated.

## Claims

### Claim 1

A method of reporting an aperiodic channel state by a terminal in a wireless communication system, the method comprising:
receiving a configuration for one or more channel state information (CSI) processes including a plurality of CSI-reference signal (CSI-RS) resources from a base station, wherein a precoding is applied to each of the plurality of the CSI-RS resources;
receiving an aperiodic CSI report request from the base station at subframe #n; and
transmitting an aperiodic CSI on a CSI process indicated by the received aperiodic CSI report request to the base station at subframe #n+4,
wherein the transmitted aperiodic CSI includes a CSI-RS resource index for the indicated CSI process,
wherein, when a predetermined time does not elapse after the CSI-RS resource index for the indicated CSI process was reported and last updated to the base station, the CSI-RS resource index for the indicated CSI process included in the transmitted aperiodic CSI is not updated, and
wherein the predetermined time corresponds to a time period for 5 subframes.

### Claim 2 (depends on 1)

The method of claim 1, wherein remaining channel state-related information included in the transmitted aperiodic CSI is calculated on a CSI-RS resource indicated by the CSI-RS resource index.

### Claim 3 (depends on 1)

The method of claim 1, wherein the CSI-RS resource index is always transmitted together with other channel state-related information.

### Claim 4 (depends on 1)

The method of claim 1, wherein the transmitted aperiodic CSI includes the CSI-RS resource index for the CSI process which is not updated when a specific time does not elapse after the CSI-RS resource index for the CSI process indicated by the aperiodic CSI report request was reported and the total number of antenna ports for all CSI-RS resources of the CSI process exceeds a threshold.

### Claim 5 (depends on 1)

The method of claim 1, wherein the transmitted aperiodic CSI includes the CSI-RS resource index for the CSI process which is not updated when a specific time does not elapse after the CSI-RS resource index for the CSI process indicated by the aperiodic CSI report request was reported and the number of the plurality of the CSI-RS resources exceeds a threshold.

### Claim 6

A terminal configured to report an aperiodic channel state in a wireless communication system, comprising:
a transmitter;
a receiver; and
a processor operatively coupled to and controlling the transmitter and the receiver,
wherein the processor is configured to:
receive a configuration for one or more channel state information (CSI) processes including a plurality of CSI-reference signal (CSI-RS) resources from a base station, wherein a precoding is applied to each of the plurality of the CSI-RS resources,
receive an aperiodic CSI report request from the base station at subframe #n, and
transmit an aperiodic CSI on a CSI process indicated by the received aperiodic CSI report request to the base station at subframe #n+4,
wherein the transmitted aperiodic CSI includes a CSI-RS resource index for the indicated CSI process,
wherein, when a predetermined time does not elapse after the CSI-RS resource index for the indicated CSI process was reported and last updated to the base station, the CSI-RS resource index for the indicated CSI process included in the transmitted aperiodic CSI is not updated, and
wherein the predetermined time corresponds to a time period for 5 subframes.

### Claim 7 (depends on 6)

The terminal of claim 6, wherein remaining channel state-related information included in the transmitted aperiodic CSI is calculated on a CSI-RS resource indicated by the CSI-RS resource index.

### Claim 8 (depends on 6)

The terminal of claim 6, wherein the CSI-RS resource index is always transmitted together with other channel state-related information.

### Claim 9 (depends on 6)

The terminal of claim 6, wherein the transmitted aperiodic CSI includes the CSI-RS resource index for the CSI process which is not updated when a specific time does not elapse after the CSI-RS resource index for the CSI process indicated by the aperiodic CSI report request was reported and the total number of antenna ports for all CSI-RS resources of the CSI process exceeds a threshold.

### Claim 10 (depends on 6)

The terminal of claim 6, wherein the transmitted aperiodic CSI includes the CSI-RS resource index for the CSI process which is not updated when a specific time does not elapse after the CSI-RS resource index for the CSI process indicated by the aperiodic CSI report request was reported and the number of the plurality of the CSI-RS resources exceeds a threshold.