Method and system for antenna interference cancellation

• US 7,729,431 B2
• Filed: 02/08/2008
• Issued: 06/01/2010
• Est. Priority Date: 11/17/2003
• Status: Expired due to Fees

• Current Assignee: Intersil Americas LLC (Renesas Electronics Corporation)
• Original Assignee: Quellan, Inc. (Renesas Electronics Corporation)
• Inventors: Laskar, Joy, Kim, Andrew Joo, Tentzeris, Emmanouil M., Gebara, Edward
• Primary Examiner(s): Tran; Khai
• Application Number:
  US12/069,236
• Publication Number:
  US 20080146183A1
• Time in Patent Office: 844 Days
• Field of Search: 375/259, 375/364, 375/284, 375/224, 375/285, 455/63, 455/562, 455/295, 342/357.1
• US Class Current: 375/259
• CPC Class Codes: H01Q 1/521 reducing the coupling between adjacent antennas
• CPC Class Codes: H01Q 1/525 between emitting and receiving antennas
• CPC Class Codes: H04B 1/1027 assessing signal quality or detecting noise/interference for the received signal
• CPC Class Codes: H04B 1/1036 with automatic suppression of narrow band noise or interference, e.g. by using tuneable notch filters H04B1/123 takes precedence; filter circuits H03H
• CPC Class Codes: H04B 1/126 having multiple inputs, e.g. auxiliary antenna for receiving interfering signal aerials in general H01Q
• CPC Class Codes: H04B 1/525 with means for reducing leakage of transmitter signal into the receiver
• CPC Class Codes: H04B 7/15585 by interference cancellation
• CPC Class Codes: H04L 1/24 Testing correct operation
• CPC Class Codes: H04L 7/00 Arrangements for synchronising receiver with transmitter synchronisation of generators of electric oscillations or pulses H03L7/00

Abstract

A wireless communication system can comprise two or more antennas that interfere with one another via free space coupling, surface wave crosstalk, dielectric leakage, or other interference effect. The interference effect can produce an interference signal on one of the antennas. A cancellation device can suppress antenna interference by generating an estimate of the interference signal and subtracting the estimate from the interference signal. The cancellation device can generate the estimate based on sampling signals on an antenna that generates the interference or on an antenna that receives the interference. The cancellation device can comprise a model of the crosstalk effect. Transmitting test signals on the communication system can define or refine the model.

Claims

1. A method for suppressing interference that a first antenna imposes on a second antenna, wherein the first antenna and the second antenna are disposed at a wireless communication device, the method comprising the steps of:

producing a signal in response to processing a sample of the imposed interference; and

reducing the imposed interference in response to applying the produced signal to a feed line for the second antenna,

wherein the feed line comprises a first section of feed line and a second section of feed line, the first section of feed line between the second antenna and the second section of feed line,

wherein the method further comprises the step of obtaining the sample from the first section of feed line, and

wherein the step of applying the produced signal comprises applying the produced signal to the second section of feed line.

2. A method for suppressing interference that a first antenna imposes on a second antenna, wherein the first antenna and the second antenna are disposed at a wireless communication device, the method comprising the steps of:

producing a signal in response to processing a sample of the imposed interference; and

reducing the imposed interference in response to applying the produced signal to a feed line for the second antenna,

wherein the feed line comprises a first section of feed line and a second section of feed line, the first section of feed line between the second antenna and the second section of feed line,

wherein the method further comprises the step of obtaining the sample from the second section of feed line, and

wherein the step of applying the produced signal comprises applying the produced signal to the first section of feed line.

3. A method for suppressing interference that a first antenna imposes on a second antenna, wherein the first antenna and the second antenna are disposed at a wireless communication device, the method comprising the steps of:

producing a signal in response to processing a sample of the imposed interference; and

reducing the imposed interference in response to applying the produced signal to a feed line for the second antenna,

wherein the feed line comprises;

a first feed line section;

a second feed line section between the first feed line section and the second antenna; and

a third feed line section between the second feed line section and the second antenna,

wherein the step of producing the signal in response to processing the sample of the imposed interference comprises;

obtaining the sample from the third feed line section; and

processing the obtained sample according to an adjustable parameter, and

wherein the step of applying the produced signal comprises applying the produced signal to the second feed line section.

4. The method of claim 3, further comprising the steps of:

obtaining another sample from the third feed line section; and

changing the adjustable parameter according to the another sample.

5. The method of claim 4, wherein the adjusting step comprises evaluating residual interference in response to assessing the another sample for residual interference, and wherein changing the adjustable parameter comprises refining interference cancellation.

6. A system, for managing interference in a wireless communication device that comprises a first antenna and a second antenna and that is operable to transmit wireless information in response to operating the first antenna and the second antenna, the system comprising signal processing circuitry operable to:

cancel first interference on the first antenna according to a first signal propagating on the second antenna; and

cancel second interference on the second antenna according to a second signal propagating on the first antenna,

wherein the operability to cancel the first interference on the first antenna comprises a first circuit that is operable to;

obtain a first sample of the first signal from the second antenna;

emulate the first interference in response to processing the first sample with a first interference model; and

apply the processed first sample to the first antenna, and

wherein the operability to cancel the second interference on the second antenna comprises a second circuit that is operable to;

obtain a second sample of the second signal from the first antenna;

emulate the second interference in response to processing the second sample with a second interference model; and

apply the processed second sample to the second antenna.

7. A system for suppressing interference between a first antenna and a second antenna, comprising

a first circuit comprising:

a first input port that is operable to receive first signals from a first signal path leading to the first antenna;

first signal processing circuitry that is operable to produce first interference cancellation signals in response to processing the received first signals; and

a first output port that is operable to output the first interference cancellation signals for delivery to a second signal path leading to the second antenna; and

a second circuit comprising;

a second input port that is operable to receive second signals from the second signal path;

second signal processing circuitry that is operable to produce second interference cancellation signals in response to processing the received second signals; and

a second output port that is operable to output the second interference cancellation signals for delivery to the first signal path.

8. The system of claim 7, wherein the system comprises two standardized modules, one of the two standardized modules comprising the first circuit, the other of the two standardized modules comprising the second circuit.

9. The system of claim 7, wherein the first signal processing circuitry comprises a first emulation filter corresponding to a first antenna frequency, and wherein the second signal processing circuitry comprises a second emulation filter corresponding to a second antenna frequency that is distinct from the first antenna frequency.

10. The system of claim 7, wherein the first input port, the second input port, the first output port, and the second output port each comprises a respective pin out.

11. The system of claim 7, wherein the first signal processing circuitry comprises a first phase adjuster in electrical series with a first variable gain amplifier, and

wherein the second signal processing circuitry comprises a second phase adjuster in electrical series with a second variable gain amplifier.

12. A pair of modules for suppressing interference on a system of two antennas, each of the modules comprising:

a port operable to receive a portion of a signal intended for propagation on one of the two antennas;

signal processing circuitry for processing the received portion of the signal to produce an interference cancellation signal; and

another port operable to output the interference cancellation signal for application to a feed line of the other one of the two antennas.

13. The pair of modules of claim 12, wherein one module is operable to cancel interference propagating in one direction between the two antennas, and wherein the other module is operable to cancel interference propagating in an opposite direction between the two antennas.

14. The pair of modules of claim 12, wherein one of the two modules is operable to suppress interference transferring from a first of the two antennas to a second of the two antennas, and

wherein the other of the two modules is operable to suppress interference transferring from the second of the two antennas to the first of the two antennas.

15. The pair of modules of claim 12, wherein one of the two modules is oriented for suppressing interference transferring from a first of the two antennas to a second of the two antennas, and

wherein the other of the two modules is oriented for suppressing interference transferring from the second of the two antennas to the first of the two antennas.

16. A method for suppressing interference, comprising the steps of:

receiving a first signal from a first signal path leading to a first antenna;

producing a first interference cancellation signal in response to processing the received first signal;

outputting the first interference cancellation signal for delivery to a second signal path leading to a second antenna;

receiving a second signal from the second signal path;

producing a second interference cancellation signal in response to processing the received second signal; and

outputting the second interference cancellation signal for delivery to the first signal path.