Wireless full-duplex system and method using sideband test signals

• US 10,063,364 B2
• Filed: 10/25/2016
• Issued: 08/28/2018
• Est. Priority Date: 11/30/2013
• Status: Active Grant

• Current Assignee: Amir Keyvan Khandani
• Original Assignee: Amir Keyvan Khandani
• Inventors: Khandani, Amir Keyvan
• Primary Examiner(s): HO, DUC CHI
• Application Number:
  US15/334,013
• Publication Number:
  US 20170041124A1
• Time in Patent Office: 672 Days
• CPC Class Codes: H04B 1/50 using different frequencies for the two directions of communication
• 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 17/0085 using test signal generators
• CPC Class Codes: H04B 7/0413 MIMO systems
• CPC Class Codes: H04L 1/0031 Multiple signaling transmission H04L1/1664, F15 take precedence
• CPC Class Codes: H04L 5/0048 Allocation of pilot signals, i.e. of signals known to the receiver
• CPC Class Codes: H04L 5/14 Two-way operation using the same type of signal, i.e. duplex
• CPC Class Codes: H04L 5/1423 for simultaneous baseband signals
• CPC Class Codes: H04L 5/1461 Suppression of signals in the return path, i.e. bidirectional control circuits

Abstract

A full-duplex transceiver is provided with componentry and methods for cancellation of nonlinear self-interference signals. The transceiver is capable of receiving an incoming radio-frequency signal that includes both a desired radio-frequency signal component and a self-interference component caused by the transceiver'"'"'s own radio-frequency transmission. The transceiver demodulates the incoming radio-frequency signal to generate a first demodulated signal. The transceiver combines an analog corrective signal with the first demodulated signal to generate a second demodulated signal with reduced self-interference. The transceiver processes the first and second demodulated signals to determine a desired incoming baseband signal and to determine nonlinear components of the self-interference signal, such as nonlinearities introduced by the transceiver'"'"'s power amplifier.

Claims

1. A full-duplex amplify-and-forward relay comprising:

a transmit up-converter operative to up-convert a relay signal to generate an outgoing radio-frequency communication signal having a center frequency;

a transmit antenna operative to transmit the outgoing radio-frequency communication signal;

an auxiliary up-converter operative to up-convert the relay signal to generate an auxiliary radio-frequency signal having substantially the same center frequency as the outgoing radio-frequency communication signal;

a receive antenna operative to receive an incoming radio-frequency signal, wherein the incoming radio-frequency signal includes (i) an incoming radio-frequency communication signal having substantially the same center frequency as the outgoing radio-frequency communication signal and (ii) a self-interference component caused by the transmitted radio-frequency communication signal;

a coupler operative to combine the auxiliary radio-frequency signal with the incoming radio-frequency signal to at least partially cancel the self-interference component from a coupler output signal; and

a down-converter operative to down-convert the coupler output signal to generate the relay signal.

2. The method of claim 1, wherein the transmit up-converter is operative to cancel remaining self-interference in the relay signal.

3. The method of claim 1, wherein the auxiliary up-converter is operative to cancel remaining self-interference in the relay signal.

4. The method of claim 1,

wherein the transmit up-converter uses a first carrier with a first carrier frequency that is offset in frequency from a second carrier with a second carrier frequency, and

wherein the down-converter uses the second carrier.

5. The full-duplex amplify-and-forward relay of claim 1, further comprising:

a second receive antenna operative to receive a second incoming radio-frequency signal, wherein the second incoming radio-frequency signal includes (i) a second radio-frequency communication signal having substantially the same center frequency as the outgoing radio-frequency communication signal and (ii) a self-interference component caused by the transmitted radio-frequency communication signal; and

a second coupler operative to combine the first coupler output signal with the second incoming radio-frequency signal to at least partially cancel the self-interference component from a second coupler output signal,

wherein the coupler operative to combine the auxiliary radio-frequency signal with the incoming radio-frequency signal is the first coupler operative to combine the auxiliary radio-frequency signal with the incoming radio-frequency signal to at least partially cancel the self-interference component from the first coupler output signal, and

wherein the down-converter operative to down-convert the coupler output signal is operative to down-convert the second coupler output signal.

6. A method performed by a full-duplex amplify-and-forward relay, the method comprising:

up-converting a relay signal with a primary up-converter to generate an outgoing radio-frequency communication signal having a center frequency;

transmitting the outgoing radio-frequency communication signal;

up-converting the relay signal with an auxiliary up-converter to generate an auxiliary radio-frequency signal having substantially the same center frequency as the outgoing radio-frequency communication signal;

receiving an incoming radio-frequency signal, wherein the incoming radio-frequency signal includes (i) an incoming radio-frequency communication signal having substantially the same center frequency as the outgoing radio-frequency communication signal and (ii) a self-interference component caused by the transmitted radio-frequency communication signal;

combining the auxiliary radio-frequency signal with the incoming radio-frequency signal to generate an incoming radio-frequency signal with reduced self-interference; and

down-converting the incoming radio-frequency signal with reduced self-interference to generate the relay signal.

7. The method of claim 6, wherein the primary up-converter uses a carrier with magnitude and phase adjusted according to remaining self-interference in the relay signal.

8. The method of claim 6, wherein the auxiliary up-converter uses a carrier with magnitude and phase adjusted according to remaining self-interference in the relay signal.

9. The method of claim 6,

wherein the primary up-converter uses a first carrier with a first carrier frequency that is offset in frequency from a second carrier with a second carrier frequency, and

wherein down-converting the incoming radio-frequency signal with reduced self-interference uses the second carrier.

10. The method of claim 6, further comprising:

receiving a second incoming radio-frequency signal, wherein the second incoming radio-frequency signal includes (i) a second incoming radio-frequency communication signal having substantially the same center frequency as the outgoing radio-frequency communication signal and (ii) a second self-interference component caused by the transmitted radio-frequency communication signal; and

combining the first incoming radio-frequency signal with reduced self-interference with the second incoming radio-frequency signal to generate a second incoming radio-frequency signal with reduced self-interference,

wherein combining the auxiliary radio-frequency signal with the incoming radio-frequency signal combines the auxiliary radio-frequency signal with the first incoming radio-frequency signal to generate the combined incoming radio-frequency signal with reduced self-interference, and

wherein down-converting the incoming radio-frequency signal down-converts the combined incoming radio-frequency signal with reduced self-interference to generate the relay signal.

11. The method of claim 6, further comprising:

searching for a preamble in the received incoming radio-frequency signal;

detecting a link direction from the preamble;

exchanging the transmit and receive antennas if the detected link direction is different than a current link direction; and

matching a polarization of each transmit antenna with a corresponding receive antenna.

12. A method performed by a full-duplex amplify-and-forward relay, the method comprising:

transmitting a combined radio-frequency signal including (i) an outgoing radio-frequency communication signal having a center frequency and (ii) a primary radio-frequency training signal;

while transmitting the combined radio-frequency signal, receiving an incoming radio-frequency signal, wherein the incoming radio-frequency signal includes (i) an incoming radio-frequency communication signal having substantially the same center frequency as the outgoing radio-frequency communication signal, (ii) a primary radio-frequency training component caused by the transmitted primary radio-frequency training signal, and (iii) a self-interference component caused by the transmitted radio-frequency communication signal;

measuring a self-interference channel based on the received primary radio-frequency training component;

using the measured self-interference channel, at least partly canceling the self-interference component and the radio-frequency training component from the incoming radio-frequency signal to obtain the incoming radio-frequency communication signal;

down-converting the incoming radio-frequency communication signal to obtain a baseband communication signal; and

using the baseband communication signal to measure the self-interference channel.

13. The method of claim 12, wherein at least partially canceling the self-interference component comprises generating an auxiliary signal, weighting the auxiliary signal based on the measured self-interference channel, and combining the weighted auxiliary signal with the incoming radio-frequency communication signal.

14. The method of claim 13, further comprising:

superimposing an auxiliary radio-frequency training signal on the auxiliary signal, wherein the incoming radio-frequency signal includes an auxiliary radio-frequency training component caused by the superimposed auxiliary training signal;

measuring an auxiliary channel based on the received primary radio-frequency training component; and

further weighting the auxiliary signal based on the measured auxiliary channel.

15. The method of claim 14, wherein the auxiliary training signal is spread with a pseudorandom sequence.

16. The method of claim 12, wherein the primary training signal is spread with a pseudorandom sequence.

17. The method of claim 12, wherein the primary training signal has a substantially lower power than the outgoing radio-frequency communication signal.

18. The method of claim 12, further comprising:

while transmitting the combined radio-frequency signal, receiving a second incoming radio-frequency signal, wherein the second incoming radio-frequency signal includes (i) a second incoming radio-frequency communication signal having substantially the same center frequency as the outgoing radio-frequency communication signal, (ii) a second primary radio-frequency training component caused by the transmitted primary radio-frequency training signal, and (iii) a second self-interference component caused by the transmitted radio-frequency communication signal;

using the measured self-interference channel, at least partly canceling the second self-interference component and the second primary radio-frequency training component from the second incoming radio-frequency signal to obtain the second incoming radio-frequency communication signal; and

combining the second incoming radio-frequency communication signal with the incoming radio-frequency communication signal to obtain a combined incoming radio-frequency communication signal,

wherein down-converting the incoming radio-frequency communication signal down-converts the combined incoming radio-frequency communication signal to obtain the baseband communication signal.

19. The method of claim 12, wherein down-converting the incoming radio-frequency communication signal to obtain the baseband communication signal comprises:

down-converting the incoming radio-frequency communication signal to an intermediate frequency signal; and

down-converting the intermediate frequency signal to the baseband communication signal.

20. The method of claim 12, further comprising:

searching for a preamble in the received incoming radio-frequency signal;

detecting a link direction from the preamble;

exchanging the transmit and receive antennas if the detected link direction is different than a current link direction; and

matching a polarization of each transmit antenna with a corresponding receive antenna.