Multi-tap adaptive filter for transmit signal leakage cancellation

Patent metadata

Field	Value
Publication number	US-9252831-B2
Application number	US-201313782366-A
Country	US
Kind code	B2
Filing date	Mar 1, 2013
Priority date	Mar 1, 2013
Publication date	Feb 2, 2016
Grant date	Feb 2, 2016

Abstract

Exemplary embodiments are directed to systems, devices, and methods for mitigating effects of transmit signal leakage. A transceiver may include a transmitter and a receiver. The transceiver may further include a multi-tap analog adaptive filter coupled to each of the transmitter and the receiver and configured to generate an estimated transmit leakage signal based on at least a portion of a transmit signal from the transmitter and an error signal from the receiver.

First claim

What is claimed is:

1. A transceiver, comprising:
a transmitter;
a receiver; and
a multi-tap analog adaptive filter coupled to each of the transmitter and the receiver and configured to generate an estimated transmit leakage signal based on at least a portion of a transmit signal from the transmitter and an error signal from the receiver, and to convey the estimated transmit leakage signal to a coupler connected to an input of the receiver.

2. The transceiver of claim 1 , the multi-tap analog adaptive filter comprising
a plurality of least means square (LMS) algorithm units configured to generate a plurality of coefficients in response to receipt of the at least a portion of the transmit signal and the error signal.

3. The transceiver of claim 2 , the plurality of LMS algorithm units comprising:
a first LMS algorithm unit configured to generate a first coefficient of the plurality of coefficients in response to receipt of the at least a portion of the transmit signal and the error signal; and
a second LMS algorithm unit configured to generate a second coefficient of the plurality of coefficients in response to receipt of the at least a portion of the transmit signal and the error signal.

4. The transceiver of claim 1 , further comprising a coupler for summing the estimated transmit leakage signal and a composite signal including transmit signal leakage.

5. The transceiver of claim 1 , the multi-tap analog adaptive filter coupled to an output of a low-noise amplifier of the receiver and an output of a power amplifier of the transmitter.

6. The transceiver of claim 1 , the at least a portion of the transmit signal comprising a third harmonic of the transmit signal.

7. The transceiver of claim 1 , further comprising a coupler coupled between an output of a power amplifier of the transmitter and an input of the multi-tap analog adaptive filter and configured as one of a broadband coupler and a frequency selective filter.

8. The transceiver of claim 7 , the coupler configured as the frequency selective filter for conveying a harmonic of the transmit signal to the multi-tap analog adaptive filter.

9. The transceiver of claim 1 , the multi-tap analog adaptive filter comprising:
a first multiplier for multiplying the error signal and the at least a portion of the transmit signal;
a second multiplier for multiplying the error signal and a time-delayed version of the at least a portion of the transmit signal;
a first integrator for receiving an output of the first multiplier and generating a first coefficient; and
a second integrator for receiving an output of the second multiplier and generating a second coefficient.

10. The transceiver of claim 9 , further comprising:
a third multiplier for multiplying the first coefficient and the at least a portion of the transmit signal;
a fourth multiplier for multiplying the second coefficient and the time-delayed version of the at least a portion of the transmit signal; and
a summer for summing an output of the third multiplier and an output of the fourth multiplier.

11. A multi-tap analog adaptive filter, comprising:
a first unit for receiving an error signal from a receiver and generating a first weight based on the error signal from the receiver;
a second unit for receiving the error signal from the receiver and generating a second weight based on the error signal from the receiver;
a filter configured to generate a transmit signal leakage estimate based on a harmonic of a transmit signal, a time-delayed version of the harmonic, the first weight, and the second weight; and
a coupler for summing the transmit signal leakage estimate and a composite signal including transmit signal leakage.

12. The multi-tap analog adaptive filter of claim 11 , the first unit comprising:
a quadrature splitter for receiving the harmonic;
a multiplier for receiving the error signal and an output of the quadrature splitter; and
a low-pass filter for receiving an output of the multiplier and conveying the first weight.

13. The multi-tap analog adaptive filter of claim 11 , the second unit comprising:
a quadrature splitter for receiving the time-delayed version of the harmonic;
a multiplier for receiving the error signal and an output of the quadrature splitter; and
a low-pass filter for receiving an output of the multiplier and conveying the second weight.

14. The multi-tap analog adaptive filter of claim 11 , the filter comprising:
a first path including a first quadrature splitter for receiving the harmonic, a first multiplier for multiplying an output of the first quadrature splitter and the second weight, and a first summer for combining in-phase and quadrature signals of the first multiplier;
a second path including a second quadrature splitter for receiving the time-delayed version of the harmonic, a second multiplier for receiving an output of the second quadrature splitter and the second weight, and a second summer for combining in-phase and quadrature signals of the second multiplier; and
a summer for combining an output of the first summer with an output of the second summer.

15. A transceiver, comprising:
a plurality of transmitters;
at least one receiver; and
a multi-tap analog adaptive filter coupled to a receiver of the at least one and configured for selective coupling to a transmitter of the plurality of transmitters, the multi-tap analog adaptive filter configured to generate an estimated transmit leakage signal based on at least a portion of a transmit signal from the transmitter selectively coupled thereto and an error signal from a receiver, and to convey the estimated transmit leakage signal a coupler connected to an input of the receiver.

16. The transceiver of claim 15 , wherein the receiver for receiving a signal via a first antenna and the transmitter selectively coupled to the multi-tap analog adaptive filter is configured to either transmit a signal via the first antenna or transmit a signal via a second, different antenna.

17. The transceiver of claim 15 , further comprising another multi-tap analog adaptive filter coupled to another receiver of the at least one receiver and configured for selectively coupling to another transmitter of the plurality of transmitters, the another multi-tap analog adaptive filter configured to generate another estimated transmit leakage signal based on at least a portion of another transmit signal from the another transmitter selectively coupled thereto and another receive signal from the another receiver.

18. A method, comprising:
generating an estimated transmit leakage signal using a plurality of weights based on at least a portion of a transmit signal and an error signal including a receive signal, the error signal being from a receiver;
subtracting the estimated transmit leakage from a composite signal including the receive signal to produce a resulting signal; and
conveying the resulting signal to an input of the receiver.

19. The method of claim 18 , the generating an estimated transmit leakage signal using a plurality of weights comprising generating the estimated transmit leakage signal with a multi-tap least means square (LMS) analog adaptive filter.

20. The method of claim 18 , the generating an estimated transmit leakage signal using a plurality of weights comprising:
generating a first weight of the plurality of weights based on the at least a portion of the transmit signal and the error signal; and
generating a second weight of the plurality of weights based on a time-delayed version of

Assignees

• Qualcomm Inc

Inventors

• Rimini Roberto
• Nguyen Cong T
• Heidmann Peter D
• Burke Joseph Patrick
• Aparin Vladimir

Classifications

• H04B1/525 Primary

  with means for reducing leakage of transmitter signal into the receiver · CPC title

• H04B1/44 Primary

  Transmit/receive switching · CPC title