Systems and methods for non-linear digital self-interference cancellation

• US 10,050,659 B2
• Filed: 04/25/2017
• Issued: 08/14/2018
• 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
• Primary Examiner(s): LAM, KENNETH T
• Application Number:
  US15/496,225
• Publication Number:
  US 20170279480A1
• Time in Patent Office: 476 Days
• 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 communication system that generates a first pre-processed digital transmit signal and a second 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 first transform configuration;

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

a transform adaptor that sets the first and second transform configurations; and

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

2. The system of claim 1, wherein the first pre-processed digital transmit signal and the second pre-processed digital transmit signal are non-identical.

3. The system of claim 2, wherein the pre-processor samples the digital transmit signal at a first sample rate;

wherein the second pre-processed digital transmit signal is generated at the first sample rate;

wherein the first pre-processed digital transmit signal is generated at a second sample rate;

wherein the second sample rate is reduced from the first sample rate.

4. The system of claim 2, wherein the pre-processor splits the digital transmit signal into linear and non-linear components;

wherein the first pre-processed digital transmit signal comprises the non-linear components;

wherein the second pre-processed digital transmit signal comprises the linear components.

5. The system of claim 4, wherein the pre-processor samples the digital transmit signal at a first sample rate;

wherein the second pre-processed digital transmit signal is generated at the first sample rate;

wherein the first pre-processed digital transmit signal is generated at a second sample rate;

wherein the second sample rate is reduced from the first sample rate.

6. The system of claim 5, wherein the linear components change at a first change rate;

wherein the non-linear components change at a second change rate;

wherein the transform adaptor sets the second sample rate based on the first and second change rates.

7. The system of claim 1, further comprising an analog signal sampler;

wherein the digital transmit signal is converted to a radio-frequency (RF) analog transmit signal by an RF receiver;

wherein the analog signal sampler generates an analog-sourced digital transmit signal from the RF analog transmit signal;

wherein the transform adaptor sets the first and second transform configurations based on the analog-sourced digital transmit signal.

8. The system of claim 7, wherein the pre-processor generates the first and second pre-processed digital transmit signals from a combination of the digital transmit signal and the analog-sourced digital transmit signal.

9. The system of claim 7, wherein the pre-processor generates the first and second pre-processed digital transmit signals from the digital transmit signal when transmitter power is below a threshold level;

wherein the pre-processor generates the first and second pre-processed digital transmit signals from the analog-sourced digital transmit signal when transmitter power is above or equal to the threshold level.

10. The system of claim 7, further comprising a digital pre-distortion circuit coupled to digital transmit signal after the pre-processor that distorts the digital transmit signal to create inverse non-linearity in the digital transmit signal;

wherein the inverse non-linearity results in reduced non-linearity when the digital transmit signal is converted to the RF analog transmit signal by the RF receiver.

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

receiving a digital transmit signal of a communication system;

pre-processing the digital transmit signal to generate first and second pre-processed digital transmit signals from the digital transmit signal;

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

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

combining the linear and non-linear self-interference signals with a digital receive signal of the communication system.

12. The method of claim 11, wherein the first pre-processed digital transmit signal and the second pre-processed digital transmit signal are non-identical.

13. The method of claim 12, further comprising sampling the digital transmit signal at a first sample rate;

generating the second pre-processed transmit signal at the first sample rate; and

generating the first pre-processed transmit signal at a second sample rate;

wherein the second sample rate is reduced from the first sample rate.

14. The method of claim 12, further comprising splitting the digital transmit signal into linear and non-linear components;

wherein the first pre-processed digital transmit signal comprises the non-linear components;

wherein the second pre-processed transmit signal comprises the linear components.

15. The method of claim 14, further comprising sampling the digital transmit signal at a first sample rate;

generating the second pre-processed transmit signal at the first sample rate; and

generating the first pre-processed transmit signal at a second sample rate;

wherein the second sample rate is reduced from the first sample rate.

16. The method of claim 15, wherein the linear components change at a first change rate;

wherein the non-linear components change at a second change rate;

further comprising setting the second sample rate based on the first and second change rates.

17. The method of claim 11, further comprising converting the digital transmit signal to a radio-frequency (RF) analog transmit signal;

generating an analog-sourced digital transmit signal from the RF analog transmit signal; and

setting the first and second transform configurations based on the analog-sourced digital transmit signal.

18. The method of claim 17, wherein generating the first and second pre-processed digital transmit signals comprises generating the first and second pre-processed digital transmit signals from a combination of the digital transmit signal and the analog-sourced digital transmit signal.

19. The method of claim 17, wherein generating the first and second pre-processed digital transmit signals comprises generating the first and second pre-processed digital transmit signals from the digital transmit signal when transmitter power is below a threshold level;

wherein generating the first and second pre-processed digital transmit signals comprises generating the first and second pre-processed digital transmit signals from the analog-sourced digital transmit signal when transmitter power is above or equal to the threshold level.

20. The method of claim 17, further comprising distorting the digital transmit signal to create inverse non-linearity in the digital transmit signal;

wherein the inverse non-linearity results in reduced non-linearity when the digital transmit signal is converted to the RF analog transmit signal.