APPARATUS AND METHOD FOR MINIMIZING ERRORS BY A CELL EDGE USER IN A MULTI-CELL COMMUNICATION SYSTEM

• US 20120020425A1
• Filed: 04/02/2010
• Published: 01/26/2012
• Est. Priority Date: 04/02/2009
• Status: Active Grant

• Current Assignee: Industry Academic Cooperation Foundation, Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Lee, Joo-Hyun, Lee, Jong-Hyeuk, Lee, Chung-Yong, Kim, Myoung-Seok, Kim, Sunghwan, Noh, Hoon-Dong
• Granted Patent: US 9,391,687 B2
• Time in Patent Office: Days
• US Class Current: 375/267
• 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 7/0639 Using selective indices, e.g. of a codebook, e.g. pre-distortion matrix index [PMI] or for beam selection
• CPC Class Codes: H04L 25/0228 with direct estimation from sounding signals
• CPC Class Codes: H04L 25/0246 with factorisation

Abstract

The present invention relates to performance improvement in a cell edge, particularly, to a method for selecting a precoder for a terminal in a multiple antenna system, wherein the method comprises: performing channel estimation for reference signals of a serving base station and another base station; determining a minimum singular value by using the channel estimation result; and if a complete collaborative feedback structure is used, feeding back a table of the determined, minimum singular value to the base stations.

Claims

1. A precoder selection method of a terminal in a multiple antenna system, the method characterized by comprising:

performing channel estimation for reference signals of a serving base station and another base station;

determining a minimum singular value using the channel estimation result; and

in a case where a full feedback cooperative scheme is used, feeding back a table of the determined minimum singular value to the base station.

2. The method of claim 1, characterized in that determining the minimum singular value using the channel estimation result comprises:

determining a coefficient matrix of a nulling filter of a receive end nulling or reducing a signal of the another base station; and

determining the minimum singular value using a multiplication of a channel estimation matrix for the reference signals of the serving base station and another base station and the coefficient matrix of the nulling filter.

3. The method of claim 1, characterized by further comprising:

in a case where a reduced feedback cooperative scheme is used, selecting a code word combination to be used by the serving base station among the determined minimum singular values; and

feeding back the selected code word combination to the base station.

4. The method of claim 3, characterized in that the code word combination comprises a minimum singular value when a code word used by the another base station is worst selected among all code words available by the serving base station, and an index of a code word maximizing the minimum singular value.

5. The method of claim 1, characterized by further comprising, in a case where a cooperative scheme is not used, feeding back, to the serving base station, an index of a code word maximizing the minimum singular value when a code word used by the another base station is worst selected among all code words available by the serving base station, among the determined minimum singular values.

6. A precoder selection method of a base station in a multiple antenna system, the method characterized by comprising:

receiving setting information from a terminal;

in a case where a cooperative scheme is used, exchanging the setting information with setting information of another base station;

in a case where the cooperative scheme is used, selecting a code word minimizing errors for the entire system based on the setting information and the setting information of the another base station; and

in a case where the cooperative scheme is not used, selecting a code word minimizing errors for the entire system based on the setting information.

7. The method of claim 6, characterized in that the setting information comprises at least one of a minimum singular value table and an index for the minimum singular value table.

8. An apparatus of a terminal of selecting a code word in a multiple antenna system, the apparatus characterized by comprising:

a channel estimator for performing channel estimation for reference signals of a serving base station and another base station;

a minimum singular value calculator for determining a minimum singular value using the channel estimation result; and

a transmitter for, in a case where a full feedback cooperative scheme is used, feeding back a table of the determined minimum singular value to the base station.

9. The apparatus of claim 8, characterized in that the minimum singular value calculator determines the minimum singular value using the channel estimation result, by determining a coefficient matrix of a nulling filter of a receive end nulling or reducing a signal of another base station, and determining the minimum singular value using a multiplication of a channel estimation matrix for the reference signals of the serving base station and another base station and the coefficient matrix of the nulling filter.

10. The apparatus of claim 8, characterized in that, in a case where a reduced feedback cooperative scheme is used, the minimum singular value calculator selects a code word combination to be used by the serving base station among the determined minimum singular values, and

feeds back the selected code word combination to the base station.

11. The apparatus of claim 10, characterized in that the code word combination comprises a minimum singular value when a code word used by the another base station is worst selected among all code words available by the serving base station, and an index of a code word maximizing the minimum singular value.

12. The apparatus of claim 8, characterized in that, in a case where a cooperative scheme is not used, the minimum singular value calculator selects an index of a code word maximizing the minimum singular value when a code word used by the another base station is worst selected among all code words available by the serving base station, among the determined minimum singular values, and

wherein the transmitter feeds back the index of the code word to the serving base station.

13. An apparatus of a base station of selecting a precoder in a multiple antenna system, the apparatus characterized by comprising:

a minimum singular value comparator for receiving setting information from a terminal, and exchanging and comparing with setting information of another base station; and

a code word selector for, in a case where a cooperative scheme is used, exchanging the setting information with setting information of another base station, selecting a code word minimizing errors for the entire system based on the setting information and the setting information of the another base station and, in a case where the cooperative scheme is not used, selecting a code word minimizing errors for the entire system based on the setting information.

14. The apparatus of claim 13, characterized in that the setting information comprises at least one of a minimum singular value table and an index for the minimum singular value table.