METHOD AND DEVICE FOR TRANSMITTING/RECEIVING CHANNEL STATE INFORMATION IN COORDINATED MULTIPOINT COMMUNICATION SYSTEM

• US 20130058307A1
• Filed: 06/08/2011
• Published: 03/07/2013
• Est. Priority Date: 06/08/2010
• Status: Active Grant

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Kim, Hyungtae, Kim, Kijun
• Granted Patent: US 9,054,852 B2
• Time in Patent Office: Days
• US Class Current: 370/329
• 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 7/0626 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 7/065 Variable contents, e.g. long-term or short-short
• CPC Class Codes: H04L 2025/03426 transmission using multiple-input and multiple-output channels
• CPC Class Codes: H04L 2025/03808 Transmission of equaliser coefficients
• CPC Class Codes: H04L 25/03343 Arrangements at the transmitter end
• CPC Class Codes: H04L 25/03955 in combination with downlink estimations, e.g. downlink path losses
• CPC Class Codes: H04L 5/0023 Time-frequency-space
• CPC Class Codes: H04L 5/0035 Resource allocation in a cooperative multipoint environment
• CPC Class Codes: H04L 5/0053 Allocation of signaling, i.e. of overhead other than pilot signals
• CPC Class Codes: H04L 5/0057 Physical resource allocation for CQI
• CPC Class Codes: H04L 5/0091 Signaling for the administration of the divided path

Abstract

The present invention relates to a wireless communication system. More particularly, disclosed are a method and a device for transmitting channel state information in a coordinated multipoint communication system. The method for transmitting channel state information from a terminal to multiple base stations, according to one embodiment of the present invention, comprise the steps of: transmitting the CSI including long-term broadband PMI and short-term sub-band PMI to a first base station; transmitting the CSI including the long-term broadband PMI and not including the short-term sub-band PMI to a second base station; and transmitting the CSI including the short-term sub-band PMI to the second base station, when a request for the short-term sub-band PMI transmission to the second base station is received.

Claims

1. A method for transmitting CSI of multiple base stations from a user equipment, the method comprising:

transmitting Channel State Information (CSI) including long-term-wideband Precoding Matrix Information (PMI) and short-term-subband PMI regarding a first base station;

transmitting CSI which includes long-term-wideband PMI regarding a second base station and does not include short-term-subband PMI regarding the second base station; and

transmitting CSI including the short-term-subband PMI regarding the second base station upon receiving a request for the short-term-subband PMI regarding the second base station.

2. The method according to claim 1, wherein the request for the short-term-subband PMI regarding the second base station is received together with an identifier of the user equipment.

3. The method according to claim 1, wherein a Channel Quality Information (CQI) difference indicating a change of CQI from current CQI to CQI due to a Coordinated Multi-Point (CoMP) operation of the first and second base stations is transmitted together with the CSI including the short-term-subband PMI regarding the second base station.

4. The method according to claim 1, wherein the first base station is a serving base station and the second base station is a neighboring base station which can participate in a CoMP operation.

5. The method according to claim 1, wherein the CSI regarding the first base station is transmitted to the first base station and the CSI regarding the second base station is transmitted to the first base station or the second base station.

6. The method according to claim 1, wherein the CSI regarding the second base station includes a Rank Indicator (RI) and the RI is fixed to 1 or is equal to a rank value regarding the first base station.

7. A method for supporting Coordinated Multi-Point (CoMP) communication in a first base station, the method comprising:

receiving Channel State Information (CSI) including long-term-wideband Precoding Matrix Information (PMI) and short-term-subband PMI regarding the first base station and CSI which includes long-term-wideband PMI regarding a second base station and does not include short-term-subband PMI regarding the second base station from a user equipment;

transmitting CSI regarding the second base station to the second base station;

receiving a request for the short-term-subband PMI regarding the second base station from the second base station and providing the request to the user equipment; and

receiving CSI including the short-term-subband PMI regarding the second base station from the user equipment and providing the CSI to the second base station.

8. The method according to claim 7, wherein the request for the short-term-subband PMI regarding the second base station is received together with an identifier of the user equipment and the request for the short-term-subband PMI regarding the second base station and an identifier of the user equipment are provided to the user equipment.

9. The method according to claim 7, wherein a Channel Quality Information (CQI) difference indicating a change of CQI from current CQI to CQI due to a Coordinated Multi-Point (CoMP) operation of the first and second base stations is received together with the CSI including the short-term-subband PMI regarding the second base station from the user equipment and the CSI including the short-term-subband PMI regarding the second base station from the user equipment and the CQI difference are provided to the second base station.

10. The method according to claim 7, wherein the first base station is a serving base station and the second base station is a neighboring base station which can participate in a CoMP operation.

11. The method according to claim 7, wherein the CSI regarding the second base station includes a Rank Indicator (RI) and the RI is fixed to 1 or is equal to a rank value regarding the first base station.

12. A method for supporting Coordinated Multi-Point (CoMP) communication in a second base station, the method comprising:

receiving Channel State Information (CSI) which includes long-term-wideband Precoding Matrix Information (PMI) regarding the second base station and does not include short-term-subband PMI regarding the second base station;

transmitting a request for the short-term-subband PMI regarding the second base station upon determining that CoMP communication is to be performed with a first base station based on the CSI regarding the second base station; and

receiving CSI including the short-term-subband PMI regarding the second base station.

13. The method according to claim 12, wherein the CSI regarding the second base station is received from the first base station or a user equipment that is to perform CoMP communication.

14. The method according to claim 12, wherein the request for the short-term-subband PMI regarding the second base station is transmitted together with an identifier of a user equipment that is to perform CoMP communication.

15. The method according to claim 12, wherein the first base station is a serving base station and the second base station is a neighboring base station which can participate in a CoMP operation.

16. The method according to claim 12, wherein the CSI regarding the second base station includes a Rank Indicator (RI) and the RI is fixed to 1 or is equal to a rank value regarding the first base station.

17. A user equipment for transmitting Channel State Information (CSI) of multiple base stations, the user equipment comprising:

a reception module for receiving a downlink signal from first and second base stations;

a transmission module for transmitting an uplink signal to the first and second base stations; and

a processor for controlling the user equipment including the reception module and the transmission module,

wherein the processor is configured to transmit CSI including long-term-wideband Precoding Matrix Information (PMI) and short-term-subband PMI regarding a first base station through the transmission module, to transmit CSI which includes long-term-wideband PMI regarding a second base station and does not include short-term-subband PMI regarding the second base station through the transmission module, and to transmit CSI including the short-term-subband PMI regarding the second base station through the transmission module upon receiving a request for the short-term-subband PMI regarding the second base station through the reception module.

18. A first base station supporting Coordinated Multi-Point (CoMP) communication, the first base station comprising:

a reception module for receiving an uplink signal from a user equipment and receiving inter-base-station information from a second base station;

a transmission module for transmitting a downlink uplink signal to the user equipment and transmitting inter-base-station information to the second base station; and

a processor for controlling the first base station including the reception module and the transmission module,

wherein the processor is configured to receive Channel State Information (CSI) including long-term-wideband Precoding Matrix Information (PMI) and short-term-subband PMI regarding the first base station and CSI which includes long-term-wideband PMI regarding the second base station and does not include short-term-subband PMI regarding the second base station from the user equipment through the reception module, to transmit CSI regarding the second base station to the second base station through the transmission module, to receive a request for the short-term-subband PMI regarding the second base station from the second base station through the reception module and provide the request to the user equipment through the transmission module, and to receive CSI including the short-term-subband PMI regarding the second base station from the user equipment through the reception module and provide the CSI to the second base station through the transmission module.

19. A second base station supporting Coordinated Multi-Point (CoMP) communication, the second base station comprising:

a reception module for receiving an uplink signal from a user equipment and receiving inter-base-station information from a first base station;

a transmission module for transmitting a downlink uplink signal to the user equipment and transmitting inter-base-station information to the first base station; and

a processor for controlling the second base station including the reception module and the transmission module,

wherein the processor is configured to receive Channel State Information (CSI) which includes long-term-wideband Precoding Matrix Information (PMI) regarding the second base station and does not include short-term-subband PMI regarding the second base station through the reception module, to transmit a request for the short-term-subband PMI regarding the second base station upon determining that CoMP communication is to be performed with a first base station based on the CSI regarding the second base station through the transmission module, and to receive CSI including the short-term-subband PMI regarding the second base station through the reception module.