SYSTEMS AND METHODS FOR ADAPTIVELY-TUNED DIGITAL SELF-INTERFERENCE CANCELLATION

• US 20170310508A1
• Filed: 07/12/2017
• Published: 10/26/2017
• Est. Priority Date: 12/16/2015
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Kumu Networks, Inc.
• Inventors: Moorti, Rajendra Tushar, Choi, Jung-Il, Jain, Mayank
• Granted Patent: US 10,200,217 B2
• Time in Patent Office: Days
• CPC Class Codes: H04B 1/525 with means for reducing leakage of transmitter signal into the receiver
• CPC Class Codes: H04B 1/56 with provision for simultaneous communication in two directions
• CPC Class Codes: H04L 25/0204 of multiple channels
• CPC Class Codes: H04L 25/03006 Arrangements for removing intersymbol interference
• CPC Class Codes: H04L 25/0328 with interference cancellation circuitry adaptations for interference cancellation within a sequence estimator H04L25/03305; interference related aspects of direct sequence spread spectrum H04B1/7097; interference related aspects of frequency hopping spread spectrum H04B1/715; see also H04B1/10
• CPC Class Codes: H04L 27/2651 Modification of fast Fourier transform [FFT] or discrete Fourier transform [DFT] demodulators for performance improvement
• CPC Class Codes: H04L 47/29 using a combination of thresholds
• CPC Class Codes: H04L 5/14 Two-way operation using the same type of signal, i.e. duplex
• CPC Class Codes: H04L 5/1461 Suppression of signals in the return path, i.e. bidirectional control circuits

Abstract

A method for adaptively-tuned digital self-interference cancellation includes generating a digital self-interference cancellation signal from a digital transmit signal based on a transform configuration; combining the digital self-interference cancellation signal with a receive signal to form a digital residue signal; generating a composite residue signal from the digital residue signal and the digital transmit signal; and updating the transform configuration based on the composite residue signal.

Claims

1. A method for adaptively-tuned digital self-interference cancellation comprising:

at a digital self-interference canceller of a communication system, receiving a digital transmit signal from a transmitter of the communication system;

receiving a transform configuration of the digital self-interference canceller;

generating a digital self-interference cancellation signal from the digital transmit signal based on the transform configuration;

combining the digital self-interference cancellation signal with a receive signal to form a digital residue signal;

generating a composite residue signal from the digital residue signal and the digital transmit signal;

wherein the composite residue signal is non-identical to the digital residue signal; and

updating the transform configuration based on the composite residue signal.

2. The method of claim 1, wherein updating the transform configuration based on the composite residue signal comprises computing a self-interference channel from the composite residue signal and updating the transform configuration based on the computed self-interference channel.

3. The method of claim 2, wherein computing the self-interference channel comprises converting the composite residue signal to a frequency domain to form a frequency-domain-converted composite residue signal;

and computing the self-interference channel based on the frequency-domain-converted composite residue signal.

4. The method of claim 3, wherein computing the self-interference channel comprises computing the self-interference channel in a time domain based on the frequency-domain-converted composite residue signal to form a time-domain-converted self-interference channel.

5. The method of claim 2, wherein generating the composite residue signal from the digital residue signal and the digital transmit signal comprises:

converting the digital residue signal to a frequency domain to form a frequency-domain-converted digital residue signal;

converting the digital transmit signal to the frequency domain to form a frequency-domain-converted digital transmit signal; and

generating a frequency-domain composite residue signal from the frequency-domain-converted digital residue signal and the frequency-domain-converted digital transmit signal.

6. The method of claim 4, wherein computing the self-interference channel further comprises computing the self-interference channel based on the frequency-domain composite residue signal.

7. The method of claim 6, wherein computing the self-interference channel comprises computing the self-interference channel in a time domain based on the frequency-domain composite residue signal to form a time-domain-converted self-interference channel.

8. The method of claim 1, wherein updating the transform configuration based on the composite residue signal comprises:

generating an updated transform configuration in a frequency domain based on the composite residue signal;

modifying the updated transform configuration in the frequency domain according to a transform modification configuration;

converting the modified updated transform configuration to a time domain; and

updating the transform configuration based on the time-domain-converted modified updated transform configuration.

9. The method of claim 8, wherein modifying the updated transform configuration comprises smoothing, in the frequency domain, at least one of a magnitude response of the updated transform configuration and a phase response of the updated transform configuration.

10. The method of claim 9, wherein smoothing a response comprises identifying a rapidly varying section of the response and modifying the response in the rapidly varying section.

11. A method for adaptively-tuned digital self-interference cancellation comprising:

at a digital self-interference canceller of a communication system, receiving a digital transmit signal from a transmitter of the communication system;

receiving a transform configuration of the digital self-interference canceller;

generating a digital self-interference cancellation signal from the digital transmit signal based on the first transform configuration;

combining the digital self-interference cancellation signal with a receive signal to form a digital residue signal;

generating a composite residue signal from the digital residue signal and the digital transmit signal;

wherein the composite residue signal is non-identical to the digital residue signal; and

generating an updated transform configuration in a frequency domain based on the composite residue signal;

modifying the updated transform configuration in the frequency domain according to a transform modification configuration;

converting the modified updated transform configuration to a time domain; and

updating the transform configuration based on the time-domain-converted modified updated transform configuration.

12. The method of claim 11, wherein modifying the updated transform configuration in the frequency domain causes a size reduction of the time-domain-converted modified updated transform configuration.

13. The method of claim 11, wherein modifying the updated transform configuration comprises smoothing a magnitude response in the frequency domain of the updated transform configuration.

14. The method of claim 13, wherein smoothing the magnitude response comprises identifying a rapidly varying section of the magnitude response based on a derivative of the magnitude response with respect to frequency, and modifying the rapidly varying section to reduce the derivative of the magnitude response.

15. The method of claim 14, wherein modifying the rapidly varying section comprises replacing the rapidly varying section with an exponential decay response fit to the rapidly varying section.

16. The method of claim 14, wherein modifying the rapidly varying section comprises replacing the rapidly varying section with a polynomial response fit to the rapidly varying section.

17. The method of claim 14, wherein modifying the rapidly varying section comprises filtering the rapidly varying section using median filtering or convolution filtering.

18. The method of claim 11, wherein modifying the updated transform configuration comprises smoothing a phase response in the frequency domain of the updated transform configuration.

19. The method of claim 18, wherein smoothing the phase response comprises identifying a rapidly varying section of the phase response based on a derivative of the phase response with respect to frequency, and modifying the rapidly varying section to reduce the derivative of the phase response.

20. The method of claim 19, wherein modifying the rapidly varying section comprises replacing the rapidly varying section with a linear response fit to the rapidly varying section.

21. The method of claim 19, wherein modifying the rapidly varying section comprises filtering the rapidly varying section using median filtering or convolution filtering.