COMMUNICATIONS DEVICE WITH SIMULTANEOUS TRANSMIT AND RECEIVE AND RELATED METHODS

• US 20150146765A1
• Filed: 11/27/2013
• Published: 05/28/2015
• Est. Priority Date: 11/27/2013
• Status: Active Grant

• Current Assignee: Smartsky Networks Llc
• Original Assignee: Harris Corporation (L3Harris Technologies, Inc.)
• Inventors: MOFFATT, Christopher D., Hoffmann, John E., Lilley, Richard
• Granted Patent: US 9,461,698 B2
• Time in Patent Office: Days
• US Class Current: 375/219
• CPC Class Codes: H04B 1/40 Circuits
• CPC Class Codes: H04B 1/525 with means for reducing leakage of transmitter signal into the receiver
• 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

Abstract

A communications device may include a transmit path, a receive path operable simultaneously with the transmit path and at a same frequency as the transmit path, and processing circuitry. The processing circuitry may be configured to generate a baseband signal for the transmit path, generate a feedforward signal based upon the baseband signal, and use the feedforward signal to reduce self-interference in the receive path from the transmit path.

Claims

1. A communications device comprising:

a transmit path;

a receive path operable simultaneously with said transmit path and at a same frequency as said transmit path; and

processing circuitry configured to

generate a baseband signal for said transmit path,

generate a feedforward signal based upon the baseband signal, and

use the feedforward signal to reduce self-interference in said receive path from said transmit path.

2. The communications device of claim 1 wherein said processing circuitry is configured to generate the feedforward signal as an inverted replica of the baseband signal.

3. The communications device of claim 1 wherein said receive path is configured to generate an error signal so that the feedforward signal is further based upon the error signal.

4. The communications device of claim 3 wherein the error signal is based upon a frequency domain response of said receive path.

5. The communications device of claim 1 wherein said transmit path has at least one non-linear characteristic;

and wherein said processing circuitry is configured to pre-distort the baseband signal based upon the at least one non-linear characteristic.

6. The communications device of claim 1 wherein said transmit path has a transmit output signal;

and wherein said processing circuitry is configured to time align the feedforward signal based upon the transmit output signal and scale the feedforward signal based upon the transmit output signal.

7. The communications device of claim 1 wherein said processing circuitry is configured to generate the baseband signal comprising an orthogonal frequency-division multiplexing (OFDM) signal.

8. The communications device of claim 1 wherein said receive path comprises a combiner configured to combine the feedforward signal and a receive signal.

9. The communications device of claim 1 further comprising at least one antenna coupled to said transmit and said receive paths.

10. The communications device of claim 9 wherein said at least one antenna comprises a first antenna coupled to said transmit path, and a second antenna coupled to said receive path.

11. A communications device comprising:

a transmit path;

a receive path operable simultaneously with said transmit path and at a same frequency as said transmit path and configured to generate an error signal;

at least one antenna coupled to said transmit and said receive paths; and

processing circuitry configured to

generate a baseband signal for said transmit path,

generate a feedforward signal as an inverted replica of the baseband signal and based upon the error signal, and

use the feedforward signal to reduce self-interference in said receive path from said transmit path.

12. The communications device of claim 11 wherein the error signal is based upon a frequency domain response of said receive path.

13. The communications device of claim 11 wherein said transmit path has at least one non-linear characteristic;

and wherein said processing circuitry is configured to pre-distort the baseband signal based upon the at least one non-linear characteristic.

14. The communications device of claim 11 wherein said transmit path has a transmit output signal;

and wherein said processing circuitry is configured to time align the feedforward signal based upon the transmit output signal and scale the feedforward signal based upon the transmit output signal.

15. The communications device of claim 11 wherein said processing circuitry is configured to generate the baseband signal comprising an orthogonal frequency-division multiplexing (OFDM) signal.

16. The communications device of claim 11 wherein said receive path comprises a combiner configured to combine the feedforward signal and a receive signal.

17. A method of operating a communications device comprising a transmit path, and a receive path operable simultaneously with the transmit path and at a same frequency as the transmit path, the method comprising:

operating processing circuitry coupled to the transmit and receive paths to

generate a baseband signal for the transmit path,

generate a feedforward signal based upon the baseband signal, and

use the feedforward signal to reduce self-interference in the receive path from the transmit path.

18. The method of claim 17 further comprising operating the processing circuitry to generate the feedforward signal as an inverted replica of the baseband signal.

19. The method of claim 17 further comprising operating the receive path to generate an error signal so that the feedforward signal is further based upon the error signal.

20. The method of claim 19 wherein the error signal is based upon a frequency domain response of the receive path.

21. The method of claim 17 further comprising operating the processing circuitry to pre-distort the baseband signal based upon at least one non-linear characteristic of the transmit path.

22. The method of claim 17 further comprising operating the processing circuitry to time align the feedforward signal based upon a transmit output signal and scale the feedforward signal based upon the transmit output signal.

23. The method of claim 17 further comprising operating the processing circuitry to generate the baseband signal comprising an orthogonal frequency-division multiplexing (OFDM) signal.