Method and System for Improved Interference Cancellation by Path Selection

• US 20130077524A1
• Filed: 09/16/2010
• Published: 03/28/2013
• Est. Priority Date: 09/16/2010
• Status: Active Grant

• Current Assignee: Zte Wistron Telecom AB (ZTE Corporation)
• Original Assignee: Zte Wistron Telecom AB (ZTE Corporation)
• Inventors: Grubeck, Hans
• Granted Patent: US 9,203,526 B2
• Time in Patent Office: Days
• US Class Current: 370/252
• CPC Class Codes: H04B 1/7107 Subtractive interference cancellation
• CPC Class Codes: H04B 15/00 Suppression or limitation of noise or interference by means associated with receiver H04B1/10

Abstract

The present invention discloses method and system for improving performance of interference cancellation in a radio communication system. The method comprises: estimating power of an interfering signal contained in a received signal; estimating power of an additive estimate error signal added to the interfering signal; and canceling the interfering signal from the received signal if the estimated power of the additive estimate error signal is lower than the estimated power of the interfering signal. A cellular mobile terminal and a cellular base station comprising the system are also disclosed.

Claims

1. A method for improving performance of interference cancellation in a radio communication system, comprising steps of:

estimating power of an interfering signal contained in a received signal;

estimating power of an additive estimate error signal added to the interfering signal; and

canceling the interfering signal from the received signal if the estimated power of the additive estimate error signal is lower than the estimated power of the interfering signal.

2. A method according to claim 1, wherein the step of estimating power of an interfering signal contained in a received signal comprises:

coherently integrating over reference symbols; and

calculating power of the coherently integrated reference symbols.

3. A method according to claim 1, wherein the step of estimating power of an additive estimate error signal added to the interfering signal comprises:

demodulating the reference symbols; and

calculating a variance of the demodulated reference symbols.

4. A method according to claim 1, wherein the step of canceling the interfering signal from the received signal comprises:

estimating channel coefficients of the interfering signal;

reconstructing the interfering signal by using the estimated channel coefficients and hard decisions made on transmitted symbols; and

canceling the reconstructed interfering signal from the received signal.

5. A method according to claim 4, wherein the channel coefficients are estimated by using a weighted average of the reference symbols.

6. A method according to claim 1, wherein the power of the interfering signal and the power of the additive estimate error signal are scaled by a scaling factor.

7. A method according to claim 2, wherein the reference symbols are one of followings:

received pilot symbols, decoded control symbols, and decoded data symbols.

8. A method according to claim 7, wherein the decoded control symbols are one of followings:

non-pilot DPCCH symbols, E-DPCCH symbols and HS-DPCCH.

9. A method according to claim 7, wherein the decoded data symbols are DPDCH symbols or E-DPDCH symbols.

21. A method according to claim 2, wherein the step of estimating power of an additive estimate error signal added to the interfering signal comprises:

demodulating the reference symbols; and

calculating a variance of the demodulated reference symbols.

10. A system for improving performance of interference cancellation in a radio communication system, comprising:

a first estimator configured to estimate power of an interfering signal contained in a received signal;

a second estimator configured to estimate power of an additive estimate error signal added to the interfering signal; and

a means configured to cancel the interfering signal from the received signal if the estimated power of the additive estimate error signal is lower than the estimated power of the interfering signal.

11. A system according to claim 10, wherein the first estimator comprises:

a means configured to coherently integrate over reference symbols; and

a first calculator configured to calculate power of the coherently integrated reference symbols.

12. A system according to claim 10, wherein the second estimator comprises:

a demodulator configured to demodulate the reference symbols; and

a second calculator configured to calculate a variance of the demodulated reference symbols.

13. A system according to claim 10, wherein the means configured to cancel the interfering signal from the received signal comprises:

a third estimator configured to estimate channel coefficients of the interfering signal;

a means configured to reconstruct the interfering signal by using the estimated channel coefficients and hard decisions made on transmitted symbols; and

a means configured to cancel the reconstructed interfering signal from the received signal.

14. A system according to claim 13, wherein the third estimator is further configured to estimate the channel coefficients of the interfering signal by using a weighted average of the reference symbols.

15. A system according to claim 10, further comprising:

a means configured to scale the power of the interfering signal and the power of the additive estimate error signal by a scaling factor.

16. A system according to claim 11, wherein the reference symbols are one of followings:

received pilot symbols, decoded control symbols, and decoded data symbols.

17. A method according to claim 16, wherein the decoded control symbols are one of followings:

non-pilot DPCCH symbols, E-DPCCH symbols and HS-DPCCH.

18. A method according to claim 16, wherein the decoded data symbols are DPDCH symbols or E-DPDCH symbols.

19. A cellular mobile terminal, comprising the system according to claim 10.

20. A cellular base station, comprising the system according to claim 10.