SYSTEMS AND METHODS FOR NON-LINEAR DIGITAL SELF-INTERFERENCE CANCELLATION

• US 20150043323A1
• Filed: 08/11/2014
• Published: 02/12/2015
• Est. Priority Date: 08/09/2013
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Kumu Networks, Inc.
• Inventors: Choi, Jung-Il, Jain, Mayank, Mehlman, Jeff, Hong, Steven
• Granted Patent: US 8,976,641 B2
• Time in Patent Office: Days
• US Class Current: 370/203
• CPC Class Codes: G06F 17/11 for solving equations , e.g. nonlinear equations, general mathematical optimization problems optimization specially adapted for a specific administrative, business or logistic context G06Q10/04
• CPC Class Codes: G06F 7/483 Computations with numbers represented by a non-linear combination of denominational numbers, e.g. rational numbers, logarithmic number system or floating-point numbers G06F7/4806, G06F7/4824, G06F7/49, G06F7/491, G06F7/544 take precedence
• CPC Class Codes: H04B 1/40 Circuits
• 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: H04L 5/14 Two-way operation using the same type of signal, i.e. duplex
• CPC Class Codes: H04L 5/143 for modulated signals H04L5/1469 takes precedence
• CPC Class Codes: H04L 5/1461 Suppression of signals in the return path, i.e. bidirectional control circuits

Abstract

A system and method for non-linear digital self-interference cancellation including a pre-processor that generates a first pre-processed digital transmit signal from a digital transmit signal of a full-duplex radio, a non-linear transformer that transforms the first pre-processed digital transmit signal into a non-linear self-interference signal according to a transform configuration, a transform adaptor that sets the transform configuration of the non-linear transformer, and a post-processor that combines the non-linear self-interference signal with a digital receive signal of the full-duplex radio.

Claims

1. A system for non-linear digital self-interference cancellation comprising:

a pre-processor communicatively coupled to a digital transmit signal of a full-duplex wireless communication system that generates a first pre-processed digital transmit signal from the digital transmit signal;

a non-linear transformer that transforms the first pre-processed digital transmit signal into a non-linear self-interference signal according to a transform configuration;

a transform adaptor that sets the transform configuration of the non-linear transformer; and

a post-processor that combines the non-linear self-interference signal with a digital receive signal of the full-duplex wireless communication system.

2. The system of claim 1, wherein the first pre-processed digital transmit signal is unmodified from the digital transmit signal.

3. The system of claim 1, wherein the non-linear transformer comprises a first transform path and a second transform path;

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

4. The system of claim 3, wherein the first transform path includes a model component that generates a first order non-linear self-interference signal component from the first pre-processed digital transmit signal.

5. The system of claim 4, wherein the second transform path includes an upsampler that upsamples the first pre-processed digital transmit signal by a factor of three to create an upsampled signal, a model component that generates a third order non-linear self-interference signal component from the upsampled signal, a low-pass filter that removes undesired high frequency components from the third order non-linear self-interference signal component, and a downsampler that downsamples the third order non-linear self-interference signal component by a factor of three.

6. The system of claim 5, wherein the non-linear transformer creates the non-linear self-interference signal from a weighted sum of the first order and third-order non-linear self-interference signal components.

7. The system of claim 5, further comprising a linear transformer that transforms a second preprocessed digital transmit signal into a linear self-interference signal according to a transform configuration.

8. The system of claim 7, wherein the first pre-processed and second pre-processed digital transmit signals are substantially identical.

9. The system of claim 7, wherein the pre-processor splits the digital transmit signal into non-linear components and linear components, wherein the first pre-processed digital transmit signal is primarily composed of the non-linear components and the second pre-processed digital transmit signal is primarily composed of the linear components.

10. The system of claim 3, wherein the non-linear transformer uses a generalized memory polynomial model.

11. system of claim 10, wherein the transform configuration comprises generalized memory polynomial coefficients and the generalized memory polynomial coefficients are adapted by the transform adaptor according to a gradient-descent optimization algorithm.

12. The system of claim 3, further comprising a digital pre-distortion circuit that performs digital pre-distortion on the digital transmit signal and passes a pre-distorted digital transmit signal to a transmitter of the full-duplex wireless communication system, and an analog signal sampler that provides RF transmit signal samples to the system 100, wherein the RF transmit signal samples are used to adjust the digital pre-distortion circuit.

13. A method for non-linear digital self-interference cancellation comprising:

receiving a digital transmit signal of a full-duplex wireless communication system;

transforming the digital transmit signal into a non-linear self-interference signal according to a transform configuration; and

combining the non-linear self-interference signal with a digital receive signal of the full-duplex wireless communication system.

14. The method of claim 13, wherein transforming the digital transmit signal comprises generating a first non-linear self-interference signal component and a second non-linear self-interference signal component, and combining the first and second non-linear self-interference signal components to create the non-linear self-interference signal.

15. The method of claim 14, wherein generating the first non-linear self-interference signal component comprises processing the digital transmit signal with a first-order model component and generating the second non-linear self-interference signal component comprises upsampling the digital transmit signal by a factor of three, processing the digital transmit signal with a third-order model component, filtering the digital transmit signal, and downsampling the digital transmit signal by a factor of three.

16. The method of claim 13 further comprising adapting the transform configuration dynamically based on the non-linear self-interference signal and the digital receive signal.

17. The method of claim 16, wherein adapting the transform configuration comprises adapting the transform configuration according to a gradient descent algorithm.

18. The method of claim 13, further comprising pre-processing the digital transmit signal into a linear digital transmit signal and a non-linear digital transmit signal, further comprising transforming the linear digital transmit signal into a linear self-interference signal, wherein transforming the digital transmit signal into a non-linear self-interference signal comprises transforming the non-linear digital transmit signal into a non-linear self-interference signal.

19. The method of claim 13, further comprising digitally pre-distorting the digital transmit signal using a digital pre-distortion circuit.

20. The method of claim 19, wherein the digital pre-distortion circuit is adapted according to samples of an RF transmit signal of the full-duplex wireless communication system.