EFFICIENT FEEDBACK TRANSMISSION METHOD IN MULTI-ANTENNA WIRELESS COMMUNICATION SYSTEM AND DEVICE FOR SAME

• US 20150236773A1
• Filed: 09/03/2013
• Published: 08/20/2015
• Est. Priority Date: 09/05/2012
• Status: Active Grant

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Kim, Youngtae, Park, Jonghyun, Kim, Kijun, Seo, Hanbyul
• Granted Patent: US 9,369,193 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H04B 7/0452 Multi-user MIMO systems
• CPC Class Codes: H04B 7/0456 Selection of precoding matrices or codebooks, e.g. using matrices antenna weighting
• CPC Class Codes: H04B 7/0617 for beam forming
• CPC Class Codes: H04B 7/0626 Channel coefficients, e.g. channel state information [CSI]
• 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: H04B 7/0645 Variable feedback
• CPC Class Codes: H04B 7/065 Variable contents, e.g. long-term or short-short
• CPC Class Codes: H04W 24/10 Scheduling measurement reports ; Arrangements for measurement reports
• CPC Class Codes: H04W 72/23 in the downlink direction of a wireless link, i.e. towards a terminal

Abstract

The present invention relates to a method for feeding back channel state information with respect to downlink transmission of a terminal in a wireless communication system supporting multiple antennas. Particularly, the method comprises the steps of measuring a channel with respect to downlink transmission; and transmitting a precoding matrix indicator (PMI) to which a precoding matrix for multiple antennas is applied, on the basis of the channel measuring result, wherein the multiple antennas are defined as a group of N antenna (N>0, N is an integer), and the precoding matrix for multiple antennas is determined by a precoding matrix for the group of N antennas and a phase coefficient matrix with respect to the precoding matrix for the group of N antennas.

Claims

1. A method for feeding back channel state information with respect to downlink transmission by a user equipment in a wireless communication system supporting multiple antennas, the method comprising the steps of:

performing channel measurement for the downlink transmission; and

transmitting a precoding matrix indicator (PMI) to which precoding matrixes for multiple antennas are applied, on the basis of the result of the channel measurement,

wherein the multiple antennas are defined by N number of antenna groups (N>

0, N is an integer), and the precoding matrixes for multiple antennas are determined by precoding matrixes for the N number of antenna groups and phase coefficient matrixes corresponding to the precoding matrix for the N number of antenna groups.

2. The method according to claim 1, wherein the precoding matrixes for the antenna groups are determined by a precoding matrix based on the number of antennas and a diagonal matrix based on the number of layers.

3. The method according to claim 1, wherein each of the precoding matrixes for the N number of antenna groups has a precoding pattern determined on the basis of a channel correlation between the N number of antenna groups.

4. The method according to claim 1, wherein each of the phase coefficient matrixes has a phase coefficient determined using channel state information (CSI).

5. The method according to claim 1, wherein each of the phase coefficient matrixes has a phase coefficient corresponding to a specific index, which is set to 0.

6. The method according to claim 1, further comprising the step of identifying grouping information for determining antenna groups for the multiple antennas.

7. The method according to claim 1, wherein each of the N number of antenna groups has the number of antennas set independently.

8. The method according to claim 1, wherein each of the precoding matrixes for the N number of antenna groups has the number of layers set independently.

9. The method according to claim 1, wherein each of the phase coefficient matrixes has phase factors for the N number of precoding matrixes, which are set independently.

10. The method according to claim 1, further comprising the step of receiving indication information for selecting M number of antennas selected from the N number of antenna groups (N≧

M>

0, N and M are integers).

11. A user equipment for feeding back channel state information with respect to downlink transmission in a wireless communication system supporting multiple antennas, the user equipment comprising:

a radio frequency (RF) unit; and

a processor,

wherein the processor is configured to perform channel measurement for the downlink transmission and transmitting a precoding matrix indicator (PMI) to which precoding matrixes for multiple antennas are applied, on the basis of the result of the channel measurement,

the multiple antennas are defined by N number of antenna groups (N>

0, N is an integer), and the precoding matrixes for multiple antennas are determined by precoding matrixes for the N number of antenna groups and phase coefficient matrixes corresponding to the precoding matrixes for the N number of antenna groups.