Interference cancellation apparatus and method

• US 9,973,224 B2
• Filed: 12/22/2016
• Issued: 05/15/2018
• Est. Priority Date: 06/26/2014
• Status: Active Grant

• Current Assignee: Huawei Technologies Co., Ltd. (Huawei Investment & Holding Co., Ltd.)
• Original Assignee: Huawei Technologies Co., Ltd. (Huawei Investment & Holding Co., Ltd.)
• Inventors: Liu, Sheng, Chen, Teyan
• Primary Examiner(s): Nguyen, Duc M
• Application Number:
  US15/388,968
• Publication Number:
  US 20170104506A1
• Time in Patent Office: 509 Days
• Field of Search: 455295, 455296, 455304, 455305, 455310-312
• CPC Class Codes: H04B 1/10 Means associated with receiver for limiting or suppressing noise or interference
• CPC Class Codes: H04B 1/1027 assessing signal quality or detecting noise/interference for the received signal
• CPC Class Codes: H04B 1/109 by improving strong signal performance of the receiver when strong unwanted signals are present at the receiver input
• CPC Class Codes: H04B 1/123 using adaptive balancing or compensation means adaptive filter circuits and algorithms H03H
• CPC Class Codes: H04B 1/525 with means for reducing leakage of transmitter signal into the receiver
• CPC Class Codes: H04B 7/15585 by interference cancellation
• CPC Class Codes: H04L 27/26 Systems using multi-frequency codes H04L27/32 takes precedence
• CPC Class Codes: H04W 84/042 Public Land Mobile systems, e.g. cellular systems
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]

Abstract

Embodiments of the present invention provide an interference cancellation apparatus and method. The method includes: receiving a radio frequency receive signal by using a main receive antenna; canceling a first-type self-interference component in the radio frequency receive signal according to a radio frequency reference signal, to generate a first processed signal; acquiring the reconstructed self-interference signal according to a self-interference channel parameter and the radio frequency reference signal; canceling a second-type self-interference component in the first processed signal according to the reconstructed self-interference signal to generate a second processed signal; performing down-conversion processing on the second processed signal to generate a third processed signal; performing analog to digital conversion on the third processed signal to generate a digital signal; and acquiring a digital baseband reference signal, and performing self-interference channel estimation according to the digital baseband reference signal and the digital signal to acquire the self-interference channel parameter.

Claims

1. An interference cancellation apparatus, comprising:

a main receive antenna, configured to receive a radio frequency receive signal, and transmit the radio frequency receive signal to a first-type interference canceller;

a splitter, configured to acquire a radio frequency reference signal generated according to a transmit signal, and transmit the radio frequency reference signal to the first-type interference canceller and a second-type interference reconstructor;

the first-type interference canceller, configured to receive the radio frequency reference signal transmitted by the splitter and the radio frequency receive signal transmitted by the main receive antenna, and cancel a first-type self-interference component in the radio frequency receive signal according to the radio frequency reference signal to generate a first processed signal, wherein the first-type self-interference component comprises a main-path self-interference component;

the second-type interference reconstructor, configured to generate a reconstructed self-interference signal according to a self-interference channel parameter and the radio frequency reference signal transmitted by the splitter;

a coupler, configured to receive the first processed signal and the reconstructed self-interference signal transmitted by the second-type interference reconstructor, and cancel a second-type self-interference component in the first processed signal according to the reconstructed self-interference signal to generate a second processed signal;

a down converter, configured to perform down-conversion processing on the second processed signal to generate a third processed signal; and

an analog to digital converter (ADC), configured to perform analog to digital conversion on the third processed signal to generate a digital signal;

wherein the second-type interference reconstructor is further configured to acquire a digital baseband reference signal, receive the digital signal generated by the ADC and the radio frequency reference signal transmitted by the splitter, and perform self-interference channel estimation according to the digital baseband reference signal and the digital signal to generate the self-interference channel parameter;

wherein the second-type interference reconstructor comprises;

a self-interference estimation module configured to acquire the digital baseband reference signal receive the digital signal generated by the ADC, and perform self-interference channel estimation according to the digital baseband reference signal and the digital signal to generate the self-interference channel parameter; and

a self-interference signal reconstruction module, configured to receive the radio frequency reference signal transmitted by the splitter and the self-interference channel parameter generated by the self-interference estimation module, and generate the reconstructed self-interference signal according to the self-interference channel parameter and the radio frequency reference signal;

wherein the self-interference signal reconstruction module comprises;

a first delayer group, a first amplitude and phase adjuster group, and a first combiner, wherein;

the first delayer group comprises at least one delayer, wherein the at least one delayer is connected in series, and the first delayer group is configured to receive the radio frequency reference signal, and perform delay processing on the radio frequency reference signal by using the at least one delayer sequentially, to form a delay signal of at least one radio frequency reference signal;

the first amplitude and phase adjuster group comprises at least one amplitude and phase adjuster wherein each amplitude and phase adjuster is configured to perform amplitude and phase adjustment on a delay signal of one radio frequency reference signal according to the self-interference channel parameter; and

the first combiner is configured to perform combination processing on delay signals that are of radio frequency reference signals and obtained after amplitude and phase adjustment, to generate the reconstructed self-interference signal.

2. The apparatus according to claim 1, further comprising a first amplifier, wherein the first amplifier is configured to amplify the second processed signal.

3. The apparatus according to claim 1, further comprising a second amplifier and a third amplifier, wherein:

the second amplifier is configured to amplify the first processed signal; and

the third amplifier is configured to amplify the radio frequency reference signal received by the second-type interference reconstructor.

4. The apparatus according to claim 1, wherein the self-interference signal reconstruction module further comprises:

a first radio frequency selection switch, configured to receive the delay signal of the at least one radio frequency reference signal, select, from delay signals of all radio frequency reference signals, a delay signal of at least one radio frequency reference signal according to the self-interference channel parameter, and transmit the selected delay signal of the at least one radio frequency reference signal to the first amplitude and phase adjuster group.

5. The apparatus according to claim 1, wherein the amplitude and phase adjuster comprises an attenuator and a phase shifter, wherein:

the attenuator is configured to perform, according to the self-interference channel parameter, amplitude adjustment processing on the received delay signal that is of the radio frequency reference signal and that is transmitted by a radio frequency selection switch; and

the phase shifter is configured to perform, according to the self-interference channel parameter, phase shift processing on a delay signal that is of the radio frequency reference signal and that is obtained after amplitude adjustment processing is performed by the attenuator.

6. The apparatus according to claim 1, wherein the first-type interference canceller is further configured to:

perform, based on the radio frequency receive signal, delay processing, amplitude adjustment processing, and phase adjustment processing on the radio frequency reference signal, so that an amplitude of the radio frequency reference signal is in a direction opposite or approximately opposite to an amplitude of the first-type self-interference component in the radio frequency receive signal, and that a phase of the radio frequency reference signal is the same or approximately the same as a phase of the first-type self-interference component in the radio frequency receive signal;

or

perform, based on the radio frequency receive signal, delay processing, amplitude adjustment processing, and phase adjustment processing on the radio frequency reference signal, so that an amplitude of the radio frequency reference signal is the same or approximately the same as an amplitude of the first-type self-interference component in the radio frequency receive signal, and that a difference between a phase of the radio frequency reference signal and a phase of the first-type self-interference component in the radio frequency receive signal is 180 degrees or approximately 180 degrees.

7. The apparatus according to claim 1, wherein the self-interference estimation module comprises a field programmable gate array (FPGA), a central processing unit (CPU), or an application-specific integrated circuit (ASIC).

8. An interference cancellation method, comprising:

acquiring, by an interference cancellation apparatus, a radio frequency reference signal generated according to a transmit signal;

receiving, by the interference cancellation apparatus, a radio frequency receive signal by using a main receive antenna;

cancelling, by the interference cancellation apparatus, a first-type self-interference component in the radio frequency receive signal according to the radio frequency reference signal, to generate a first processed signal, wherein the first-type self-interference component comprises a main-path self-interference component;

generating, by the interference cancellation apparatus, a reconstructed self-interference signal according to a self-interference channel parameter and the radio frequency reference signal;

cancelling, by the interference cancellation apparatus, a second-type self-interference component in the first processed signal according to the reconstructed self-interference signal to generate a second processed signal;

performing by the interference cancellation apparatus, down-conversion processing on the second processed signal to generate a third processed signal;

performing, by the interference cancellation apparatus, analog to digital conversion on the third processed signal to generate a digital signal; and

acquiring, by the interference cancellation apparatus, a digital baseband reference signal, and performing self-interference channel estimation according to the digital baseband reference signal and the digital signal to generate the self-interference channel parameter;

wherein generating the reconstructed self-interference signal according to the self-interference channel parameter and the radio frequency reference signal further comprises;

performing delay processing on the radio frequency reference signal for at least one time, to form a delay signal of at least one radio frequency reference signal;

performing amplitude and phase adjustment on a delay signal of each radio frequency reference signal according to the self-interference channel parameter; and

performing combination processing on delay signals that are of radio frequency reference signals and obtained after amplitude and phase adjustment, to generate the reconstructed self-interference signal.

9. The method according to claim 8, wherein the method further comprises:

amplifying the second processed signal.

10. The method according to claim 8, wherein the method further comprises:

amplifying the first processed signal; and

before generating the reconstructed self-interference signal according to the self-interference channel parameter and the radio frequency reference signal, amplifying the radio frequency reference signal.

11. The method according to claim 8, wherein before performing amplitude and phase adjustment on the delay signal of each radio frequency reference signal according to the self-interference channel parameter, the method further comprises:

selecting, from delay signals of all radio frequency reference signals, a delay signal of at least one radio frequency reference signal according to the self-interference channel parameter; and

wherein performing amplitude and phase adjustment on the delay signal of each radio frequency reference signal according to the self-interference channel parameter further comprises;

performing amplitude and phase adjustment on the delay signal of each radio frequency reference signal in the selected delay signal of the at least one radio frequency reference signal.

12. The method according to claim 8, wherein performing amplitude and phase adjustment on the delay signal of each radio frequency reference signal according to the self-interference channel parameter comprises:

performing amplitude adjustment processing on the delay signal of the radio frequency reference signal according to the self-interference channel parameter; and

performing, according to the self-interference channel parameter, phase shift processing on a delay signal that is of the radio frequency reference signal and that is obtained after amplitude adjustment processing is performed.

13. The method according to claim 8, wherein cancelling the first-type self-interference component in the radio frequency receive signal according to the radio frequency reference signal comprises:

performing, based on the radio frequency receive signal, delay processing, amplitude adjustment processing, and phase adjustment processing on the radio frequency reference signal, so that an amplitude of the radio frequency reference signal is in a direction opposite or approximately opposite to an amplitude of the first-type self-interference component in the radio frequency receive signal, and that a phase of the radio frequency reference signal is the same or approximately the same as a phase of the first-type self-interference component in the radio frequency receive signal;

or

performing, based on the radio frequency receive signal, delay processing, amplitude adjustment processing, and phase adjustment processing on the radio frequency reference signal, so that an amplitude of the radio frequency reference signal is the same or approximately the same as an amplitude of the first-type self-interference component in the radio frequency receive signal, and that a difference between a phase of the radio frequency reference signal and a phase of the first-type self-interference component in the radio frequency receive signal is 180 degrees or approximately 180 degrees.

14. An interference cancellation apparatus, comprising:

a main receive antenna, configured to receive a radio frequency receive signal, and transmit the radio frequency receive signal to a first-type interference canceller;

a splitter, configured to acquire a radio frequency reference signal generated according to a transmit signal, and transmit the radio frequency reference signal to the first-type interference canceller and a second-type interference reconstructor;

the first-type interference canceller, configured to receive the radio frequency reference signal transmitted by the splitter and the radio frequency receive signal transmitted by the main receive antenna, and cancel a first-type self-interference component in the radio frequency receive signal according to the radio frequency reference signal to generate a first processed signal, wherein the first-type self-interference component comprises a main-path self-interference component;

the second-type interference reconstructor, configured to generate a reconstructed self-interference signal according to a self-interference channel parameter and the radio frequency reference signal transmitted by the splitter;

a coupler, configured to receive the first processed signal and the reconstructed self-interference signal transmitted by the second-type interference reconstructor, and cancel a second-type self-interference component in the first processed signal according to the reconstructed self-interference signal to generate a second processed signal;

a down converter, configured to perform down-conversion processing on the second processed signal to generate a third processed signal; and

an analog to digital converter (ADC), configured to perform analog to digital conversion on the third processed signal to generate a digital signal;

wherein the second-type interference reconstructor is further configured to acquire a digital baseband reference signal, receive the digital signal generated by the ADC and the radio frequency reference signal transmitted by the splitter, and perform self-interference channel estimation according to the digital baseband reference signal and the digital signal to generate the self-interference channel parameter;

wherein the second-type interference reconstructor comprises;

a self-interference estimation module, configured to acquire the digital baseband reference signal, receive the digital signal generated by the ADC, and perform self-interference channel estimation according to the digital baseband reference signal and the digital signal to generate the self-interference channel parameter; and

a self-interference signal reconstruction module, configured to receive the radio frequency reference signal transmitted by the splitter and the self-interference channel parameter generated by the self-interference estimation module, and generate the reconstructed self-interference signal according to the self-interference channel parameter and the radio frequency reference signal;

wherein the self-interference signal reconstruction module comprises;

a second delayer group, a second amplitude and phase adjuster group, and a second combiner, wherein;

the second delayer group comprises at least one circulator and at least one delayer, wherein the at least one circulator is connected in series by using a first port and a third port, and one end of the delayer is connected to a second port of the circulator;

the first delayer group is configured to receive the radio frequency reference signal, and perform delay processing on the radio frequency reference signal by using the at least one delayer sequentially, to form a delay signal of at least one radio frequency reference signal;

the second amplitude and phase adjuster group comprises at least one amplitude and phase adjuster, wherein each amplitude and phase adjuster is configured to perform amplitude and phase adjustment on a delay signal of one radio frequency reference signal according to the self-interference channel parameter; and

the second combiner is configured to perform combination processing on delay signals that are of radio frequency reference signals and obtained after amplitude and phase adjustment, to generate the reconstructed self-interference signal.

15. The apparatus according to claim 14, further comprising a first amplifier, wherein the first amplifier is configured to amplify the second processed signal.

16. The apparatus according to claim 14, further comprising a second amplifier and a third amplifier, wherein:

the second amplifier is configured to amplify the first processed signal; and

the third amplifier is configured to amplify the radio frequency reference signal received by the second-type interference reconstructor.

17. The apparatus according to claim 14, wherein the self-interference signal reconstruction module further comprises:

a second radio frequency selection switch, configured to receive the delay signal of the at least one radio frequency reference signal, select, from delay signals of all radio frequency reference signals, a delay signal of at least one radio frequency reference signal according to the self-interference channel parameter, and transmit the selected delay signal of the at least one radio frequency reference signal to the second amplitude and phase adjuster group.

18. The apparatus according to claim 14, wherein the amplitude and phase adjuster comprises an attenuator and a phase shifter, wherein:

the attenuator is configured to perform, according to the self-interference channel parameter, amplitude adjustment processing on the received delay signal that is of the radio frequency reference signal and that is transmitted by a radio frequency selection switch; and

the phase shifter is configured to perform, according to the self-interference channel parameter, phase shift processing on a delay signal that is of the radio frequency reference signal and that is obtained after amplitude adjustment processing is performed by the attenuator.

19. The apparatus according to claim 14, wherein the first-type interference canceller is further configured to:

perform, based on the radio frequency receive signal, delay processing, amplitude adjustment processing, and phase adjustment processing on the radio frequency reference signal, so that an amplitude of the radio frequency reference signal is in a direction opposite or approximately opposite to an amplitude of the first-type self-interference component in the radio frequency receive signal, and that a phase of the radio frequency reference signal is the same or approximately the same as a phase of the first-type self-interference component in the radio frequency receive signal;

or

perform, based on the radio frequency receive signal, delay processing, amplitude adjustment processing, and phase adjustment processing on the radio frequency reference signal, so that an amplitude of the radio frequency reference signal is the same or approximately the same as an amplitude of the first-type self-interference component in the radio frequency receive signal, and that a difference between a phase of the radio frequency reference signal and a phase of the first-type self-interference component in the radio frequency receive signal is 180 degrees or approximately 180 degrees.

20. The apparatus according to claim 14, wherein the self-interference estimation module comprises a field programmable gate array (FPGA), a central processing unit (CPU), or an application-specific integrated circuit (ASIC).