Method and apparatus for transmitting information about a channel in a wireless communication system

• US 9,479,299 B2
• Filed: 03/19/2014
• Issued: 10/25/2016
• Est. Priority Date: 06/09/2009
• Status: Active Grant

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Kim, Hyung Tae, Seo, Han Byul, Kim, Ki Jun, Kim, Byoung Hoon
• Primary Examiner(s): LY, ANH VU H
• Application Number:
  US14/219,637
• Publication Number:
  US 20140204874A1
• Time in Patent Office: 951 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: H04B 7/024 Co-operative use of antennas of several sites, e.g. in co-ordinated multipoint or co-operative multiple-input multiple-output [MIMO] systems
• CPC Class Codes: H04B 7/0452 Multi-user MIMO systems
• CPC Class Codes: H04B 7/063 Parameters other than those covered in groups H04B7/0623 - H04B7/0634, e.g. channel matrix rank or transmit mode selection
• CPC Class Codes: H04B 7/0632 Channel quality parameters, e.g. channel quality indicator [CQI]
• CPC Class Codes: H04B 7/0639 Using selective indices, e.g. of a codebook, e.g. pre-distortion matrix index [PMI] or for beam selection
• CPC Class Codes: H04L 5/0035 Resource allocation in a cooperative multipoint environment
• CPC Class Codes: H04L 5/0048 Allocation of pilot signals, i.e. of signals known to the receiver
• CPC Class Codes: H04L 5/005 of common pilots, i.e. pilots destined for multiple users or terminals
• CPC Class Codes: H04L 5/0051 of dedicated pilots, i.e. pilots destined for a single user or terminal

Abstract

A method for feeding back channel information, and a user equipment (UE) therefore are discussed. The method according to one embodiment includes, if one or more cells are configured, performing a first feedback process and a second feeding process. The first feedback process is configured to transmit first channel information including rank information. The second feedback process is configured to transmit second channel information generated based on the same rank information as the rank information of the first feedback process.

Claims

1. A method for feeding back channel information, the method comprising:

receiving information on a maximum number of ranks;

if one or more cells are configured, performing a first feedback process and a second feedback process,

wherein the first feedback process is configured to transmit first channel information generated based on rank information,

wherein the second feedback process is configured to transmit second channel information,

wherein the second channel information is generated based on the same rank information as the rank information used for generating the first channel information of the first feedback process, and

wherein the maximum number of ranks is used to determine the rank information; and

receiving rank-related information determined by a base station based on the rank information.

2. The method of claim 1, wherein the second channel information transmitted according to the second feedback process includes at least one of a precoding matrix indicator (PMI) and channel quality information (CQI).

3. The method of claim 1, further comprising:

determining the rank information corresponding the number of antenna layers.

4. The method of claim 1, wherein the first feedback process is related to a first reference signal, and

wherein the second feedback process is related to a second reference signal.

5. The method of claim 4, wherein each of the first and second reference signals corresponds to at least one of a cell-specific reference signal (CRS) and a channel state information reference signal (CSI-RS).

6. The method of claim 1, wherein each of the first and second channel information is channel state information (CSI).

7. The method of claim 1, further comprising:

receiving a dedicated reference signal (DRS) which is beamformed based on the first channel information or the second channel information; and

transmitting updated channel information which is measured using the DRS.

8. The method of claim 1, wherein the first channel information or the second channel information is transmitted on a Physical Uplink Control Channel (PUCCH) or a Physical Uplink Shared Channel (PUSCH).

15. The method of claim 1, wherein the rank-related information is received through a downlink control information (DCI) scrambled with a radio network temporary identity (RNTI).

16. The method of claim 15, wherein the RNTI is a rank indicator-RNTI.

9. A user equipment (UE), comprising:

a Radio Frequency (RF) unit configured to transmit and receive a radio signal; and

a processor coupled to the RF unit and configured to;

receive information on a maximum number of ranks; and

perform a first feedback process and a second feedback process if one or more cells are configured,

wherein the first feedback process is configured to transmit first channel information venerated based on rank information,

wherein the second feedback process is configured to transmit channel information,

wherein the second channel information is generated based on the same rank information as the rank information used for generating the first channel information of the first feedback process, and

wherein the maximum number of ranks is used to determine the rank information; and

receive rank-related information determined by a base station based on the rank information.

10. The user equipment of claim 9, wherein the second channel information transmitted according to the second feedback process includes at least one of a precoding matrix indicator (PMI) and channel quality information (CQI).

11. The user equipment of claim 9, wherein the processor is further configured to determine the rank information corresponding to the number of antenna layers.

12. The user equipment of claim 9, wherein the first feedback process is related to a first reference signal, and

wherein the second feedback process is related to a second reference signal.

13. The user equipment of claim 12, Wherein each of the first and second reference signals corresponds to at least one of a cell-specific reference signal (CRS) and a channel state information reference signal (CSI-RS).

14. The user equipment of claim 9, wherein each of the first and second channel information is channel state information (CSI).