# US 9,520,973 B2 · Method for transmitting reference signal to antenna port in wireless access system

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- Number: US 9,520,973 B2
- Document ID: US9520973B2
- Status: Granted
- Kind: B2
- Application number: 14/414,064
- Filed: 2013-07-12
- Published: 2015-06-25
- Granted: 2016-12-13
- Earliest claimed: 2012-07-12
- Assignees: LG Electronics Inc.
- Applicants: LG Electronics Inc.
- Inventors: Jinmin Kim; Hyunsoo Ko; Jaehoon Chung
- Web page: https://patentgrep.com/patent/US9520973B2

## CPC

- 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)}
- H04B 7/0667: {of delayed versions of same signal (using space-time coding H04L1/0618)}
- H04B 7/0671: {using different delays between antennas}
- H04B 7/0891: {Space-time diversity (rake receivers H04B1/7115; space-time decoding H04L1/0631)}
- H04B 7/0894: {using different delays between antennas}
- H04L 5/0053: {Allocation of signalling, i.e. of overhead other than pilot signals}
- H04W 72/21: in the uplink direction of a wireless link, i.e. towards the network
- H04W 88/02: Terminal devices
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)
- H04B: TRANSMISSION
- H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72)

## Abstract

The present invention provides various methods for transmitting a channel state information reference signal (CSI-RS) by varying a transmission period for each antenna port or antenna port group, and also provides apparatuses supporting the methods. The method for receiving a CSI-RS in a wireless access system according to one aspect of the present invention may comprise the steps of: receiving a CSI-RS component information element for setting CSI-RS transmission periods for two or more antenna ports to be mutually different; receiving CSI-RSs for each of the two or more antenna ports based on the CSI-RS component information element; and acquiring channel state information for each of the two or more antenna ports based on the received CSI-RS.

## Claims

### Claim 1

A method for receiving a channel state information reference signal (CSI-RS) in a wireless access system, the method comprising:
receiving a CSI-RS configuration information element to be used for 3 dimensional beamforming, wherein the CSI-RS configuration information element includes antenna set number parameters indicating antenna port groups and CSI-RS subframe configuration parameters indicating different transmission periods of the CSI-RS for each of the antenna port groups;
receiving the CSI-RS for the each of the antenna port groups based on the CSI-RS configuration information element; and
obtaining a channel state information for the each of the antenna port groups based on the received CSI-RS for the each of the antenna port groups,
wherein the each of the antenna port groups has grouped for vertical beamforming and horizontal beamforming of the 3 dimensional beamforming, and
wherein the each of the antenna port groups includes two or more antennas.

### Claim 2 (depends on 1)

The method of claim 1, wherein the CSI-RS configuration information element is received via a higher layer signal.

### Claim 3 (depends on 1)

The method of claim 1, further comprising: reporting the channel state information to a base station.

### Claim 4

A user equipment (UE) for receiving a channel state information reference signal (CSI-RS) in a wireless access system, the UE comprising:
a transceiver; and
a processor configured to control the CSI-RS reception, the processor configured to receive a CSI-RS configuration information element to be used for 3 dimensional beamforming to receive the CSI-RS for each of antenna port groups based on the CSI-RS configuration information element, and to obtain a channel state information for the each of the antenna port groups based on the received CSI-RS, using the transceiver,
wherein the CSI-RS configuration information element includes antenna set number parameters indicating the each of the antenna port groups and CSI-RS subframe configuration parameters indicating different transmission periods of the CSI-RS for the each of the antenna port groups,
wherein the each of the antenna port groups has grouped for vertical beamforming and horizontal beamforming of the 3 dimensional beamforming, and
wherein the each of the antenna port groups includes two or more antennas.

### Claim 5 (depends on 4)

The user equipment of claim 4, wherein the CSI-RS configuration information element is received via a higher layer signal.

### Claim 6 (depends on 4)

The user equipment of claim 4, wherein the processor is configured to report the channel state information to a base station using the transceiver.

### Claim 7

Method for transmitting a channel state information reference signal (CSI-RS) in a wireless access system, the method comprising:
transmitting a CSI-RS configuration information element to be used for 3 dimensional beamforming, wherein the CSI-RS configuration information element includes antenna set number parameters indicating antenna port groups and CSI-RS subframe configuration parameters indicating different transmission periods of the CSI-RS for each of the antenna port groups; and
transmitting the CSI-RS for the each of the antenna port groups based on the CSI-RS configuration information element;
wherein the each of the antenna port groups has grouped for vertical beamforming and horizontal beamforming of the 3 dimensional beamforming, and
wherein the each of the antenna port groups includes two or more antennas.

### Claim 8 (depends on 7)

The method of claim 7, wherein the CSI-RS configuration information element is received via a higher layer signal.

### Claim 9 (depends on 7)

The method of claim 7, further comprising:
receiving a report including channel state information for the each of the antenna port groups obtained based on the CSI-RS.

### Claim 10

An evolved Node B (eNB) for transmitting a channel state information reference signal (CSI-RS) in a wireless access system, the eNB comprising:
a transceiver; and
a processor configured to control the CSI-RS transmission, the processor configured to transmit a CSI-RS configuration information element to be used for 3 dimensional beamforming, to transmit the CSI-RS for each of antenna port groups based on the CSI-RS configuration information element,
wherein the CSI-RS configuration information element includes antenna set number parameters indicating the each of the antenna port groups and CSI-RS subframe configuration parameters indicating different transmission periods of the CSI-RS for the each of the antenna port groups,
wherein the each of the antenna port groups has grouped for vertical beamforming and horizontal beamforming of the 3 dimensional beamforming, and
wherein the each of the antenna port groups includes two or more antennas.

### Claim 11 (depends on 10)

The eNB of claim 10, wherein the CSI-RS configuration information element is transmitted via a higher layer signal.

### Claim 12 (depends on 10)

The eNB of claim 10, wherein the processor is configured to receive a report including channel state information for the each of antenna port groups obtained based on the CSI-RS.