# US 10,122,430 B2 · Method of transmitting channel state information and apparatus therefor

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- Number: US 10,122,430 B2
- Document ID: US10122430B2
- Status: Granted
- Kind: B2
- Application number: 15/268,078
- Filed: 2016-09-16
- Published: 2017-03-23
- Granted: 2018-11-06
- Earliest claimed: 2015-09-18
- Assignees: LG Electronics Inc.
- Applicants: LG Electronics Inc.
- Inventors: Kunil Yum; Jonghyun Park
- Web page: https://patentgrep.com/patent/US10122430B2

## CPC

- H04B 7/0626: {Channel coefficients, e.g. channel state information [CSI]}
- H04B 7/0417: Feedback systems
- H04B 7/06952: {Selecting one or more beams from a plurality of beams, e.g. beam training, management or sweeping}
- H04L 5/0048: {Allocation of pilot signals, i.e. of signals known to the receiver (allocation of control signalling H04L5/0053; use of control signalling H04L5/0091)}
- H04L 5/0057: {Physical resource allocation for CQI}
- H04B: TRANSMISSION
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)

## Abstract

A method of reporting a downlink channel state, which is performed by a terminal in a wireless communication system, includes receiving a CSI process configuration including a plurality of channel state information-reference signal (CSI-RS) resources to which a different vertical precoding is applied from each other, measuring a CSI-RS on the plurality of the CSI-RS resources under an assumption that all of the plurality of the CSI-RS resources have the predetermined number of antenna ports, and reporting a beam index (BI) indicating a CSI-RS resource having a highest channel quality indicator (CQI) among the plurality of the CSI-RS resources corresponding to the measured CSI-RS resources to a base station.

## Claims

### Claim 1

A method of reporting a downlink channel state, which is performed by a terminal in a wireless communication system, the method comprising:
receiving a CSI (channel state information) process configuration containing a plurality of channel state information-reference signal (CSI-RS) resources to which a different vertical precoding is applied;
measuring a CSI-RS on each of the plurality of the CSI-RS resources under an assumption that all of the plurality of CSI-RS resources have a predetermined number of antenna ports; and
reporting, to a base station, a beam index (BI) indicating a CSI-RS resource having a highest channel quality indicator (CQI) among the plurality of CSI-RS resources,
wherein when the number of CSI-RS resources contained in the CSI process is equal to or greater than a preconfigured number of antenna ports, the BI is reported after a specific number (nCQI-ref) of subframes from a subframe which includes the plurality of CSI-RS resources.

### Claim 2 (depends on 1)

The method of claim 1, wherein the plurality of CSI-RS resources is configured to have a different number of antenna ports.

### Claim 3 (depends on 1)

The method of claim 1, wherein measuring the CSI-RS on each of the plurality of the CSI-RS resources includes calculating a CQI for one or more BI candidates; and
wherein the number of the one or more BI candidates is restricted to a number equal to or less than a predefined number.

### Claim 4

A terminal configured to report a downlink channel state in a wireless communication system, comprising:
a transmitter and a receiver; and
a processor that:
controls the receiver to receive a CSI process configuration containing a plurality of channel state information-reference signal (CSI-RS) resources to which a different vertical precoding is applied,
measures a CSI-RS on each of the plurality of CSI-RS resources under an assumption that all of the plurality of CSI-RS resources have a predetermined number of antenna ports,
reports, to a base station, a beam index (BI) indicating a CSI-RS resource having a highest channel quality indicator (CQI) among the plurality of CSI-RS resources,
wherein when the number of CSI-RS resources contained in the CSI process is equal to or greater than a preconfigured number of antenna ports, the BI is reported after a specific number (nCQI-ref) of subframes from a subframe which includes the plurality of CSI-RS resources.

### Claim 5 (depends on 4)

The user equipment of claim 4, wherein the plurality of CSI-RS resources is configured to have a different number of antenna ports.

### Claim 6 (depends on 4)

The user equipment of claim 4, wherein the processor is configured to calculate a CQI for one or more BI candidates to measure the CSI-RS on each of the plurality of CSI-RS resources, and wherein the number of the one or more BI candidates is restricted to a number equal to or less than a predefined number.