Apparatus and method for minimizing errors by a cell edge user in a multi-cell communication system

• US 9,391,687 B2
• Filed: 04/02/2010
• Issued: 07/12/2016
• Est. Priority Date: 04/02/2009
• Status: Active Grant

• Current Assignee: Industry Academic Cooperation Foundation, Samsung Electronics Co. Ltd.
• Original Assignee: Industry Academic Cooperation Foundation, Samsung Electronics Co. Ltd.
• Inventors: Lee, Joo-Hyun, Kim, Sunghwan, Lee, Jong-Hyeuk, Lee, Chung-Yong, Kim, Myoung-Seok, Noh, Hoon-Dong
• Primary Examiner(s): Washburn, Daniel
• Assistant Examiner(s): Tadese, Berhanu
• Application Number:
  US13/262,485
• Publication Number:
  US 20120020425A1
• Time in Patent Office: 2,293 Days
• Field of Search: 375/267, 375/260
• 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 7/0639 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, by the terminal, channel estimation based on reference signals of a serving base station and another base station;

determining, by the terminal, an effective channel that applies to a first plurality of code words of the serving base station by cancelling an interference channel that applies to a second plurality of code words of the other base station based on the channel estimation;

determining, by the terminal, a plurality of minimum singular values of the effective channel, according to a combination of the first plurality of code words and the second plurality of code words; and

transmitting, to the serving base station, at least one of at least one minimum singular value from the determined plurality of minimum singular values of the effective channel to the serving base station and one of the first plurality of code words.

2. The method of claim 1, further comprising:

selecting the one of the first plurality of code words.

3. The method of claim 2, wherein the step of selecting the one of the first plurality of code words comprising:

selecting a minimum value of minimum singular values of each of the first plurality of code words;

selecting a maximum value of each minimum values of the first plurality of code words; and

selecting a code word corresponding to the maximum value from the first plurality of code words.

4. The method of claim 1, further comprising:

selecting the at least one minimum singular value from the determined plurality of minimum singular values of the effective channel.

5. The method of claim 4, wherein the step of selecting the at least one minimum singular value comprising:

selecting a minimum value of minimum singular values of each of the first plurality of code words;

selecting a first maximum value of each minimum values of the first plurality of code words; and

selecting first minimum singular values of a first code word corresponding to the maximum value from the first plurality of code words.

6. The method of claim 5, further comprising:

selecting a minimum value of minimum singular values of each of the second plurality of code words;

selecting a second maximum value of each minimum values of the second plurality of code words; and

selecting second minimum singular values of a second code word corresponding to the second maximum value from the second plurality of code words.

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

receiving at least one of at least one first minimum singular value of a first effective channel and a first code word of first plurality of code words from a first terminal;

receiving at least one of at least one second minimum singular value of a second effective channel and a second code word of second plurality of code words from a second terminal; and

determining a code word set for the first terminal and a second terminal by comparing the at least one minimum singular value of the first terminal with at least one minimum singular value of the second terminal.

8. The method of claim 7, wherein the step of determining the code word set for the first terminal and a second terminal comprising:

generating at least one new minimum singular value by comparing the at least one minimum singular value of the first terminal with at least one minimum singular value of the second terminal;

selecting a maximum value of at least one new minimum singular value; and

determining the code word set of the new minimum singular value corresponding to the maximum value.

9. The method of claim 8, wherein the new minimum singular comprises a minimum value of the minimum singular value of the first terminal and the minimum singular value of the second terminal.

10. The method of claim 7, wherein if the first code word of the first terminal is different from a code word of the first terminal of the code word set, selecting the code word of the first terminal of the code word set as a code word for the first terminal, and

if the second code word of the second terminal is different from a code word of the second terminal of the code word set, selecting the code word of the second terminal of the code word set as a code word for the second terminal.

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

a channel estimator configured to perform channel estimation based on reference signals of a serving base station and another base station;

a minimum singular value calculator configured to determine an effective channel that applies to a first plurality of code words of the serving base station by cancelling an interference channel that applies to a second plurality of code words of the other base station based on the channel estimation and determine a plurality of minimum singular values of the effective channel according to a combination of the first plurality of code words and the second plurality of code words; and

a transmitter configured to transmit, to the serving base station, at least one of at least one minimum singular value from the determined plurality of minimum singular values of the effective channel and one of the first plurality of code words.

12. The apparatus of claim 11, wherein the minimum singular value calculator is further configured to selects the one of the first plurality of code words.

13. The apparatus of claim 12, wherein the minimum singular value calculator is configured to:

select a minimum value of minimum singular values of each of the first plurality of code words;

select a maximum value of each minimum values of the first plurality of code words; and

select a code word corresponding to the maximum value from the first plurality of code words.

14. The apparatus of claim 11, wherein the minimum singular value calculator is further configured to select the at least one minimum singular value from the determined plurality of minimum singular values of the effective channel.

15. The apparatus of claim 14, wherein the minimum singular value calculator is configured to:

select a minimum value of minimum singular values of each of the first plurality of code words;

select a first maximum value of each minimum values of the first plurality of code words; and

select first minimum singular values of a first code word corresponding to the maximum value from the first plurality of code words.

16. The apparatus of claim 15, wherein the minimum singular value calculator is configured to:

select a minimum value of minimum singular values of each of the second plurality of code words;

select a second maximum value of each minimum values of the second plurality of code words; and

select second minimum singular values of a second code word corresponding to the second maximum value from the second plurality of code words.

17. 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 configured to receive at least one second minimum singular value of a second effective channel and a second code word of second plurality of code words from a second terminal from a first terminal and receive at least one of at least one second minimum singular value of a second effective channel and a second code word of second plurality of code words from a second terminal; and

a code word selector configured to determine a code word set of the first terminal and a second terminal by comparing the at least one of minimum singular value of the first terminal with at least one of minimum singular value of the second terminal.

18. The apparatus of claim 17, wherein the code word selector is further configured to:

generate at least one new minimum singular value by comparing the at least one minimum singular value of the first terminal with at least one minimum singular value of the second terminal;

select a maximum value of at least one new minimum singular value; and

determine the code word set of the new minimum singular value corresponding to the maximum value.

19. The apparatus of claim 18, wherein the new minimum singular comprises a minimum value of the minimum singular value of the first terminal and the minimum singular value of the second terminal.

20. The apparatus of claim 17, wherein if the first code word of the first terminal is different from a code word of the first terminal of the code word set, the code word selector selects the code word of the first terminal of the code word set as a code word for the first terminal, and

if the second code word of the second terminal is different from a code word of the second terminal of the code word set, the code word selector selects the code word of the second terminal of the code word set as a code word for the second terminal.