Systems and methods for multi-rate digital self-interference cancellation

• US 9,276,682 B2
• Filed: 05/26/2015
• Issued: 03/01/2016
• Est. Priority Date: 05/23/2014
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Kumu Networks, Inc.
• Inventors: Bharadia, Dinesh, Choi, Jung-Il, Jain, Mayank, Moorti, Rajendra Tushar
• Primary Examiner(s): PANWALKAR, VINEETA S
• Application Number:
  US14/722,087
• Publication Number:
  US 20150341125A1
• Time in Patent Office: 280 Days
• Field of Search: 375/229, 375/230, 375/316, 375/346, 379/406.01, 379/406.05, 379/406.06, 379/406.08, 379/3, 455/70, 455/570, 370/276, 370/282, 370/286, 370/290
• US Class Current: 1/1
• CPC Class Codes: H04B 1/00 Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
• CPC Class Codes: H04B 1/123 using adaptive balancing or compensation means adaptive filter circuits and algorithms H03H
• CPC Class Codes: H04B 1/38 Transceivers, i.e. devices in which transmitter and receiver form a structural unit and in which at least one part is used for functions of transmitting and receiving
• CPC Class Codes: H04B 1/48 in circuits for connecting transmitter and receiver to a common transmission path, e.g. by energy of transmitter H04B1/46 takes precedence
• CPC Class Codes: H04B 1/525 with means for reducing leakage of transmitter signal into the receiver
• CPC Class Codes: H04B 1/62 for providing a predistortion of the signal in the transmitter and corresponding correction in the receiver, e.g. for improving the signal/noise ratio
• CPC Class Codes: H04B 15/00 Suppression or limitation of noise or interference by means associated with receiver H04B1/10
• CPC Class Codes: H04B 2001/485 inhibiting unwanted transmission
• CPC Class Codes: H04L 27/32 Carrier systems characterised by combinations of two or more of the types covered by groups H04L27/02, H04L27/10, H04L27/18 or H04L27/26
• CPC Class Codes: H04L 5/14 Two-way operation using the same type of signal, i.e. duplex

Abstract

A system for multi-rate digital self-interference cancellation including a signal component generation system coupled to a digital transmit signal of a communication system that generates a set of signal components from the digital transmit signal; a multi-rate adaptive filter that transforms the set of signal components into a digital self-interference cancellation signal, according to a transform configuration, to form an interference-reduced receive signal; and a transform adaptor that dynamically sets the transform configuration in response to changes in the interference-reduced receive signal.

Claims

1. A system for multi-rate digital self-interference cancellation comprising:

a signal component generation system coupled to a digital transmit signal of a communication system that generates a set of signal components from the digital transmit signal;

wherein the signal component generation system comprises a set of transform paths;

wherein each transform path comprises a component generator and an anti-aliasing filter;

wherein a majority of the set of transform paths further comprise an upsampler, a downsampler, and a signal multiplier;

wherein signal multipliers couple transform paths to at least one other transform path;

a multi-rate adaptive filter that transforms the set of signal components into a digital self-interference cancellation signal according to a transform configuration, wherein the digital self-interference cancellation signal is combined with a receive signal of the communication system to form an interference-reduced receive signal; and

a transform adaptor that dynamically sets the transform configuration in response to changes in the interference-reduced receive signal.

2. The system of claim 1, wherein each transform path further comprises a frequency shifter.

3. The system of claim 1, wherein the set of transform paths comprises a first transform path and a second transform path;

the first transform path having a component generator of order one, and the second transform path having a component generator of order three.

4. The system of claim 3, wherein the first transform path comprises a downsampler that downsamples by a first factor;

wherein the second transform path comprises a downsampler that downsamples by a second factor.

5. The system of claim 4, wherein the first factor and the second factor are equal.

6. The system of claim 4, wherein the second transform path further comprises an upsampler that upsamples by a third factor.

7. The system of claim 3, wherein the multi-rate adaptive filter comprises a first filter and a second filter;

wherein the self-interference cancellation signal is generated from a combination of outputs of the first filter and the second filter;

wherein the first filter transforms only first order signal components;

wherein the second filter transforms only non-first order signal components.

8. The system of claim 1, further comprising a blocker filter that removes undesired components of the self-interference cancellation signal.

9. The system of claim 8, further comprising a filter inverter coupled to the transform adaptor that reduces the effect of the blocker filter on the interference-reduced receive signal as sampled by the transform adaptor.

10. The system of claim 8, further comprising a filter inverter coupled to the transform adaptor that reduces the effect of receiver components on the interference-reduced receive signal as sampled by the transform adaptor.

11. The system of claim 1, further comprising a gain/phase compensator that modifies gain and phase of the digital self-interference cancellation signal to reduce gain/phase error relative to the receive signal.

12. The system of claim 1, further comprising a gain/phase compensator that modifies gain and phase of the receive signal to reduce gain/phase error relative to the digital self-interference cancellation signal.

13. The system of claim 1, wherein size of the set of signal components is determined by the transform configuration.

14. The system of claim 1, wherein the transform adaptor dynamically sets the transform configuration in response to changes in a ratio of a frequency-domain-transformed interference-reduced receive signal to a frequency-domain-transformed digital transmit signal.

15. A method for multi-rate digital self-interference cancellation comprising:

receiving a digital transmit signal of a communication system;

generating a set of signal components from the digital transmit signal;

wherein generating the set of signal components comprises;

generating a first signal component by upsampling the digital transmit signal;

performing signal component generation, according to a self-interference model, on the upsampled digital transmit signal;

downsampling the generated signal component; and

performing anti-aliasing filtering on the downsampled signal component;

transforming the set of signal components into a digital self-interference cancellation signal according to a transform configuration;

combining the digital self-interference cancellation signal with a receive signal of the communication system to form an interference-reduced receive signal; and

dynamically adapting the transform configuration in response to changes in the interference-reduced receive signal.

16. The method of claim 15, wherein generating the set of signal components comprises generating a second signal component by downsampling the digital transmit signal;

and performing anti-aliasing filtering on the downsampled signal.

17. The method of claim 16, wherein dynamically adapting the transform configuration comprises dynamically adapting the transform configuration in response to changes in a ratio of receive and transmit signals.

18. The method of claim 16, wherein dynamically adapting the transform configuration comprises dynamically adapting the transform configuration in response to changes in a frequency-domain-converted ratio of receive and transmit signals.

19. The method of claim 16, wherein dynamically adapting the transform configuration comprises dynamically adapting the transform configuration in response to changes in a time-averaged ratio of receive and transmit signals;

wherein the time-averaged ratio is averaged over a first number of samples.

20. The method of claim 19, wherein dynamically adapting the transform configuration further comprises dynamically changing the first number of samples.

21. The method of claim 20, wherein dynamically changing the first number of samples comprises increasing the first number of samples in response to a decrease in the time-averaged ratio of receive and transmit signals.

22. The method of claim 16, wherein dynamically adapting the transform configuration comprises dynamically adapting the transform configuration in response to changes in a ratio of a first product and a second product;

wherein the first product is a product of a receive signal and a conjugate of a transmit signal;

wherein the second product is a product of the transmit signal and the conjugate of the transmit signal.