SYSTEMS AND METHODS FOR FULL-DUPLEX SIGNAL SHAPING

• US 20160234005A1
• Filed: 04/19/2016
• Published: 08/11/2016
• Est. Priority Date: 02/08/2012
• Status: Active Grant

• Current Assignee: Board of Trustees of the Leland Stanford Junior University (Stanford Management Co.)
• Original Assignee: Board of Trustees of the Leland Stanford Junior University (Stanford Management Co.)
• Inventors: HONG, Steven, MEHLMAN, Jeff, KATTI, Sachin
• Granted Patent: US 10,243,718 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H04B 1/0475 with means for limiting noise, interference or distortion H04B1/0483 takes precedence
• CPC Class Codes: H04B 1/18 Input circuits, e.g. for coupling to an antenna or a transmission line coupling networks between antennas or lines and receivers independent of the nature of the receiver H03H
• 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: H04B 15/00 Suppression or limitation of noise or interference by means associated with receiver H04B1/10
• CPC Class Codes: H04L 27/2626 Arrangements specific to the transmitter only
• CPC Class Codes: H04L 27/2647 Arrangements specific to the receiver only equalisation H04L27/01
• CPC Class Codes: H04L 5/1423 for simultaneous baseband signals
• CPC Class Codes: H04L 5/143 for modulated signals H04L5/1469 takes precedence

Abstract

A system for processing signals includes an interference cancellation component that samples an RF transmit signal, transforms the sampled RF transmit signal into a self-interference cancellation signal, and combines the sampled RF transmit signal and self-interference cancellation signal to remove a first portion of interference from the RF receive signal, the combination forming a processed RF signal; and a filtering component that removes a second portion of interference from the processed signal by downconverting the processed RF signal to a processed baseband signal, sampling the processed baseband signal to create a processed digital signal, and filtering the processed digital signal to remove the second portion of interference.

Claims

1-22. -22. (canceled)

23. A system for processing signals, comprising:

a transmitter that transmits an RF transmit signal;

a receiver that receives an RF receive signal, wherein transmission of the RF transmit signal and reception of the RF receive signal occur simultaneously;

an interference cancellation component that samples the RF transmit signal and transforms the sampled RF transmit signal into a self-interference cancellation signal, wherein the self-interference cancellation signal is combined with the RF receive signal to remove a first portion of interference from the RF receive signal, said combination forming a processed RF signal; and

a filtering component that removes a second portion of interference from the processed signal by;

downconverting the processed RF signal to a processed baseband signal,

sampling, at a first sample rate, the processed baseband signal at an analog-to-digital converter to create a processed digital signal, and

filtering the processed digital signal to remove the second portion of interference.

24. The system of claim 23, wherein downconverting the processed RF signal comprises downconverting the processed RF signal into a narrowband stream.

25. The system of claim 23, wherein removal of the first portion of interference results in prevention of receiver saturation at the filtering component.

26. The system of claim 25, wherein the first portion of interference is larger than a dynamic range of the analog-to-digital converter.

27. The system of claim 23, wherein the interference cancellation component is configured to remove at least a predetermined amount of power from the RF receive signal through combination of the RF receive signal with the self-interference cancellation signal.

28. The system of claim 27, wherein the predetermined amount of power is set according to a dynamic range of the RF transmit signal.

29. The system of claim 27, wherein the predetermined amount of power is set according to a dynamic range of the RF receive signal.

30. The system of claim 27, wherein the predetermined amount of power is set according to a range of expected signal strength.

31. The system of claim 23, wherein the filtering component resamples the processed digital signal from the first sample rate to a second sample rate, wherein the second sample rate is higher than the first sample rate.

32. The system of claim 31, wherein the filtering component resamples the processed digital signal prior to filtering the processed digital signal.

33. The system of claim 32, wherein the filtering component further comprises an anti-aliasing filter that removes aliasing from the processed digital signal after resampling.

34. The system of claim 23, wherein the filtering component resamples the processed digital signal from the first sample rate to a second sample rate, wherein the second sample rate is lower than the first sample rate.

35. The system of claim 23, wherein the processed digital signal comprises a first digital signal stream and a second digital signal stream, wherein the filtering component resamples the first digital signal stream from the first sample rate to a second sample rate, wherein the filtering component filters the first digital signal stream after resampling and filters the second digital signal stream without resampling.

36. The system of claim 35, wherein the filtering component resamples the filtered first digital signal stream from the second sample rate to the first sample rate.

37. The system of claim 23, wherein the filtering component performs mapping of a digital transmit signal, using a digital intermediate frequency converter, to a frequency fragment in a wireless frequency band for transmission by the transmitter, wherein the transmitter converts the mapped digital transmit signal into the RF transmit signal.

38. A method for processing signals, comprising:

transmitting an RF transmit signal;

receiving an RF receive signal, wherein transmission of the RF transmit signal and reception of the RF receive signal occur simultaneously;

sampling the RF transmit signal;

transforming the sampled RF transmit signal into a self-interference cancellation signal;

combining the self-interference cancellation signal with the RF receive signal to remove a first portion of interference from the RF receive signal, said combination forming a processed RF signal;

downconverting the processed RF signal to a processed baseband signal;

sampling, at a first sample rate, the processed baseband signal at an analog-to-digital converter to create a processed digital signal; and

filtering the processed digital signal to remove a second portion of interference.

39. The method of claim 38, wherein downconverting the processed RF signal comprises downconverting the processed RF signal into a narrowband stream.

40. The method of claim 38, wherein removal of the first portion of interference results in prevention of receiver saturation, wherein the first portion of interference is larger than a dynamic range of the analog-to-digital converter.

41. The method of claim 38, wherein transforming the sampled RF transmit signal into a self-interference cancellation signal comprises transforming the sampled RF transmit signal such that, when combined with the RF receive signal, the self-interference cancellation signal enables removal of at least a predetermined amount of power from the RF receive signal.

42. The method of claim 41, wherein the predetermined amount of power is set according to at least one of:

a dynamic range of the RF transmit signal;

a dynamic range of the RF receive signal; and

a range of expected signal strength.

43. The method of claim 38, further comprising resampling the processed digital signal from the first sample rate to a second sample rate, wherein the second sample rate is higher than the first sample rate.

44. The method of claim 43, wherein resampling the processed digital signal comprises resampling the processed digital signal prior to filtering the processed digital signal.

45. The method of claim 44, further comprising filtering the processed digital signal to remove aliasing resulting from resampling.

46. The method of claim 38, wherein the processed digital signal comprises a first digital signal stream and a second digital signal stream, further comprising resampling the first digital signal stream from the first sample rate to a second sample rate, wherein filtering the processed digital signal comprises filtering the first digital signal stream after resampling and filtering the second digital signal stream without resampling.

47. The method of claim 46, further comprising resampling the filtered first digital signal stream from the second sample rate to the first sample rate.

48. The method of claim 38, further comprising performing mapping of a digital transmit signal, using a digital intermediate frequency converter, to a frequency fragment in a wireless frequency band for transmission, further comprising converting the mapped digital transmit signal into the RF transmit signal.