Method and system for automatic control in an interference cancellation device

• US 20070060059A1
• Filed: 06/09/2006
• Published: 03/15/2007
• Est. Priority Date: 12/14/2004
• Status: Active Grant

• Current Assignee: Intersil Americas LLC (Renesas Electronics Corporation)
• Original Assignee: Quellan, Inc. (Renesas Electronics Corporation)
• Inventors: Laskar, Joy, Summers, Charles, Gebara, Edward, Farrell, Michael, Kim, Andrew, Schmukler, Bruce, Stelliga, David, Dickmann, Mark, Vrazel, Michael
• Granted Patent: US 7,725,079 B2
• Time in Patent Office: Days
• US Class Current: 455/63.100
• CPC Class Codes: H04B 1/123 using adaptive balancing or compensation means adaptive filter circuits and algorithms H03H
• CPC Class Codes: H04B 1/7103 the interference being multiple access interference

Abstract

Signals propagating on an aggressor communication channel can cause detrimental interference in a victim communication channel. A signal processing circuit can generate an interference cancellation signal that, when applied to the victim communication channel, cancels the detrimental interference. The signal processing circuit can dynamically adjust or update two or more aspects of the interference cancellation signal, such as an amplitude or gain parameter and a phase or delay parameter. Via the dynamic adjustments, the signal processing circuit can adapt to changing conditions, thereby maintaining an acceptable level of interference cancellation in a fluctuating operating environment. A control circuit that implements the parametric adjustments can have at least two modes of operation, one for adjusting the amplitude parameter and one for adjusting the phase parameter. The modes can be selectable or can be intermittently available, for example.

Claims

1. A method for reducing interference imposed on a first communication signal by a second communication signal, comprising the steps of:

obtaining a sample of the second communication signal;

generating an interference compensation signal in response to processing the sample using a signal processing parameter;

reducing the interference in response to applying the generated interference compensation signal to the first communication channel;

changing the signal processing parameter;

attributing a change in the reduced interference to the change in the signal processing parameter; and

adjusting the signal processing parameter based on the attributed change.

2. The method of claim 1, wherein changing the signal processing parameter comprises perturbing the signal processing parameter and wherein adjusting the signal processing parameter comprises refining the signal processing parameter.

3. The method of claim 1, wherein adjusting the signal processing parameter comprises optimizing the signal processing parameter for improved interference compensation.

4. The method of claim 1, wherein imposing interference on the first communication signal by the second communication signal comprises an effect transferring energy from the second communication signal to the first communication signal, and

wherein adjusting the signal processing parameter comprises compensating for a change in the effect.

5. The method of claim 1, wherein at least one of the first communication signal and the second communication signal is associated with a wireless signal.

6. The method of claim 1, wherein reducing the interference comprises improving reception in a handheld cellular communication device.

7. The method of claim 1, wherein the step of changing the signal processing parameter comprises increasing the signal processing parameter,

wherein the step of attributing the change in the reduced interference comprises determining whether the reduced interference increased or decreased in response to the increase in the signal processing parameter, and

wherein the step of adjusting the signal processing parameter further comprises the steps of:

if the reduced interference is determined to have decreased in response to the increase in the signal processing parameter, further increasing the signal processing parameter; and

if the reduced interference is determined to have increased in response to the increase in the signal processing parameter, decreasing the signal processing parameter.

8. The method of claim 1, wherein the generating step comprises generating the interference compensation signal in response to processing the sample with an interference model having a plurality of signal processing parameters,

wherein the step of changing the signal processing parameter comprises perturbing at least two of the plurality of signal processing parameters, and

wherein the step of adjusting the signal processing parameter comprises optimizing the at least two of the plurality of signal processing parameters.

9. The method of claim 8, wherein perturbing the at least two of the plurality of signal processing parameters comprises simultaneously perturbing the at least two of the plurality of signal processing parameters, and

wherein optimizing the at least two of the plurality of signal processing parameters comprises simultaneously optimizing the at least two of the plurality of signal processing parameters.

10. The method of claim 8, wherein the at least two of the plurality of signal processing parameter comprise an amplitude parameter and a phase parameter.

11. The method of claim 1, further comprising the step of iterating the obtaining step, the generating step, the reducing step, the changing step, the attributing step, and the adjusting step.

12. The method of claim 1, wherein the attributing step further comprises monitoring energy of the reduced interference.

13. The method of claim 1, wherein the attributing step further comprises assessing the reduced interference via monitoring bit error rate of the first communication signal.

14. The method of claim 1, wherein the attributing step comprises using a processor to evaluate fidelity of the first communication signal.

15. A method for canceling interference associated with an interference effect between a first communication signal and a second communication signal, comprising the steps of:

generating an interference compensation signal in response to processing a sample of the first communication signal with a model of the interference effect, the model comprising a first modeling parameter and a second modeling parameter;

canceling at least a portion of the interference in response to applying the generated interference compensation signal to the second communication signal;

monitoring the second communication signal for residual interference;

determining a state of a control signal;

if the control signal is determined to have a first state, adjusting the first modeling parameter according to the monitored residual interference; and

if the control signal is determined to have a second state, adjusting the second modeling parameter according to the monitored residual interference.

16. The method of claim 15, wherein the step of adjusting the first modeling parameter further comprises holding the second modeling parameter constant, and

wherein the step of adjusting the second modeling parameter further comprises holding the first modeling parameter constant.

17. The method of claim 15, wherein the first modeling parameter comprises a gain and the second modeling parameter comprises a phase shift.

18. The method of claim 15, wherein the first modeling parameter comprises an amplitude parameter and wherein the second modeling parameter comprises a signal delay parameter.

19. The method of claim 15, wherein adjusting the first modeling parameter comprises a controller optimizing the first modeling parameter, and

wherein adjusting the second modeling parameter comprises the controller optimizing the second modeling parameter.

20. The method of claim 15, wherein monitoring the second communication signal comprises monitoring energy of the residual interference.

21. The method of claim 15, wherein monitoring the second communication signal for residual energy comprises evaluating bit error rate of the second communication signal.

22. The method of claim 15, wherein monitoring the second communication signal comprises evaluating fidelity of the second communication based on information obtained from a receiver of the second communication signal.

23. A system for canceling interference on a first communication channel associated with a transmission on a second communication channel, comprising:

a signal processing circuit, comprising;

a first port for applying an interference cancellation signal to the first communication channel;

a second port for receiving a sample of the transmission from the second communication channel; and

an operability to produce the interference cancellation signal in response to processing the transmission sample according to a first signal processing setting and a second signal processing setting; and

a controller, connected to the signal processing circuit, comprising;

a third port for obtaining interference information from the first communication channel;

a first operational mode for manipulating the first signal processing setting using the obtained interference information as feedback; and

a second operational mode for manipulating the second signal processing setting using the obtained interference information as feedback.

24. The system of claim 23, wherein the controller further comprises:

an operability to perturb at least one of the first signal processing setting and the second signal processing setting;

an operability to detect an interference response to the perturbation of the at least one of the first signal processing setting and the second signal processing setting; and

an operability to change at least one of the first signal processing setting and the second signal processing setting according to the detected interference response.

25. The system of claim 23, wherein the first signal processing setting comprises one of a gain setting and an amplitude setting,

wherein the second signal processing setting comprises one of a phase setting, a delay setting, and a signal timing setting,

wherein the first operational mode is further for manipulating the first signal processing setting while maintaining the second signal processing setting in a defined state,

wherein the second operational mode is further for manipulating the second signal processing setting while maintaining the first signal processing setting in a defined state, and

wherein the system further comprises an operability to shift the controller between the first operational mode and the second operational mode in response to an occurrence of a time event.