SYSTEMS AND METHODS FOR MODIFIED FREQUENCY-ISOLATION SELF-INTERFERENCE CANCELLATION

• US 20170353212A1
• Filed: 08/24/2017
• Published: 12/07/2017
• Est. Priority Date: 12/12/2013
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Kumu Networks, Inc.
• Inventors: Bharadia, Dinesh, Mehlman, Jeffrey, Hahn, Wilhelm Steffen
• Granted Patent: US 10,230,422 B2
• Time in Patent Office: Days
• CPC Class Codes: H04B 1/0475 with means for limiting noise, interference or distortion H04B1/0483 takes precedence
• CPC Class Codes: H04B 1/10 Means associated with receiver for limiting or suppressing noise or interference
• CPC Class Codes: H04B 1/525 with means for reducing leakage of transmitter signal into the receiver
• 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 system for frequency isolation modified self-interference cancellation includes a transmit coupler, that samples an RF transmit signal; an RF self-interference canceller that transforms the sampled RF transmit signal to an RF self-interference cancellation signal; a receive coupler that combines the RF self-interference cancellation signal with the RF receive signal to form a reduced-interference receive signal; and a frequency shifter that frequency shifts only one of the RF transmit signal and the reduced-interference receive signal.

Claims

1. A system for frequency isolation modified self-interference cancellation comprising:

a transmit coupler, communicatively coupled to a radio frequency (RF) transmit signal of a wireless communication system, that samples the RF transmit signal to create a sampled RF transmit signal having a first RF carrier frequency;

an RF self-interference canceller that transforms the sampled RF transmit signal to an RF self-interference cancellation signal;

a receive coupler, communicatively coupled to an RF receive signal of the wireless communication system, that combines the RF self-interference cancellation signal with the RF receive signal to form a reduced-interference receive signal;

wherein the RF receive signal has a second RF carrier frequency; and

a frequency shifter that frequency shifts only one of the RF transmit signal and the reduced-interference receive signal;

wherein frequency shifting only one of the RF transmit signal and the reduced-interference receive signal modifies frequency isolation between the RF transmit signal and the reduced-interference receive signal.

2. The system of claim 1, further comprising a delayer, located in a signal path between the RF self-interference canceller and the receive coupler, that delays the RF self-interference cancellation signal.

3. The system of claim 1, wherein the frequency shifter is coupled to the reduced-interference receive signal and shifts the carrier frequency of the reduced-interference receive signal such that frequency isolation between the RF transmit signal and the reduced-interference receive signal is increased.

4. The system of claim 1, wherein the frequency shifter is coupled to the reduced-interference receive signal and shifts the carrier frequency of the reduced-interference receive signal such that frequency isolation between the RF transmit signal and the reduced-interference receive signal is decreased.

5. The system of claim 1, wherein the frequency shifter is coupled to the RF transmit signal and shifts the carrier frequency of the RF transmit signal such that frequency isolation between the RF transmit signal and the reduced-interference receive signal is increased.

6. The system of claim 1, wherein the frequency shifter is coupled to the RF transmit signal and shifts the carrier frequency of the RF transmit signal such that frequency isolation between the RF transmit signal and the reduced-interference receive signal is decreased.

7. The system of claim 4, further comprising a digital self-interference canceller.

8. The system of claim 4, wherein the carrier frequency shift is tunable and is set by a tuning circuit.

9. A system for frequency isolation modified self-interference cancellation comprising:

a transmit coupler, communicatively coupled to a radio frequency (RF) transmit signal of a wireless communication system, that samples the RF transmit signal to create a sampled RF transmit signal having a first RF carrier frequency;

an RF self-interference canceller that transforms the sampled RF transmit signal to an RF self-interference cancellation signal;

a frequency downconverter that converts the RF self-interference cancellation signal to a baseband self-interference cancellation signal;

a receiver coupler, communicatively coupled to a baseband receive signal of the wireless communication system, that combines the baseband self-interference cancellation signal with the baseband receive signal to form a reduced-interference receive signal;

wherein the baseband receive signal is converted from an RF receive signal having a second RF carrier frequency; and

a frequency shifter that frequency shifts only one of the RF transmit signal and the RF receive signal;

wherein frequency shifting only one of the RF transmit signal and the RF receive signal modifies frequency isolation between the RF transmit signal and the RF receive signal.

10. The system of claim 9, further comprising a delayer, located in a signal path between the RF self-interference canceller and the receive coupler, that delays the RF self-interference cancellation signal.

11. The system of claim 9, wherein the frequency shifter is coupled to the RF transmit signal and shifts the carrier frequency of the RF transmit signal such that frequency isolation between the RF transmit signal and the RF receive signal is increased.

12. The system of claim 9, wherein the frequency shifter is coupled to the RF transmit signal and shifts the carrier frequency of the RF transmit signal such that frequency isolation between the RF transmit signal and the RF receive signal is decreased.

13. The system of claim 11, further comprising a digital self-interference canceller.

14. The system of claim 11, wherein the carrier frequency shift is tunable and is set by a tuning circuit.

15. A method for frequency-isolated self-interference cancellation comprising:

receiving an RF transmit signal of a wireless communications system;

shifting a carrier frequency of the RF transmit signal;

transforming the RF transmit signal into an RF self-interference cancellation signal using an RF self-interference canceller;

combining the RF self-interference cancellation signal with a receive signal of the wireless communications system.

16. The method of claim 15, wherein shifting the carrier frequency of the RF transmit signal comprises increasing frequency isolation between the RF transmit signal and the receive signal.

17. The method of claim 16, wherein the receive signal is an RF receive signal.

18. The method of claim 17, wherein the receive signal is a baseband receive signal;

wherein combining the RF self-interference cancellation signal with the receive signal comprises downconverting the RF self-interference cancellation signal to a baseband self-interference cancellation signal and combining the baseband self-interference cancellation signal with the baseband receive signal.

19. The method of claim 15, wherein shifting the carrier frequency of the RF transmit signal comprises decreasing frequency isolation between the RF transmit signal and the receive signal.

20. The method of claim 19, wherein the receive signal is an RF receive signal.

21. The method of claim 19, wherein the receive signal is a baseband receive signal;

wherein combining the RF self-interference cancellation signal with the receive signal comprises downconverting the RF self-interference cancellation signal to a baseband self-interference cancellation signal and combining the baseband self-interference cancellation signal with the baseband receive signal.