Method for reducing self-interference signal in communications system, and apparatus

• US 10,033,428 B2
• Filed: 05/27/2016
• Issued: 07/24/2018
• Est. Priority Date: 11/29/2013
• 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
• Primary Examiner(s): Smarth, Gerald A
• Application Number:
  US15/167,609
• Publication Number:
  US 20160277063A1
• Time in Patent Office: 788 Days
• CPC Class Codes: H04B 1/525 with means for reducing leakage of transmitter signal into the receiver
• CPC Class Codes: H04B 5/70 specially adapted for specific purposes
• 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

Abstract

Embodiments of the present invention provide a method for reducing a self-interference signal in a communications system, and an apparatus. The method includes: sending a sounding signal and a first communication signal; receiving an input signal; separating a near-field reflection signal corresponding to the sounding signal from an echo signal of the input signal; determining, based on the near-field reflection signal, a near-field reflection channel parameter; determining, based on the near-field reflection channel parameter, a reconstructed near-field reflected self-interference signal; and subtracting the reconstructed near-field reflected self-interference signal from a received second communication signal. The present invention can effectively recognize and reconstruct a near-field reflection signal, thereby reducing a near-field reflected self-interference signal in self-interference.

Claims

1. A wireless full duplex communications apparatus, wherein the apparatus comprises:

a transmitter, configured to send a sounding signal and a first communication signal through at least one antenna wherein a timeslot used for sending the sounding signal is different from a timeslot used for sending the first communication signal, and the sounding signal is a large time-bandwidth product signal;

a receiver, configured to receive an input signal through at least one antenna, wherein the input signal comprises a second communication signal sent by another apparatus and an echo signal that corresponds to the sounding signal and the first communication signal; and

a processor, configured to separate a near-field reflection signal corresponding to the sounding signal from the echo signal, wherein

the processor is further configured to determine, based on the near-field reflection signal, a near-field reflection channel parameter; and

the processor is further configured to determine, based on the near-field reflection channel parameter, a reconstructed near-field reflected self-interference signal, and subtract the reconstructed near-field reflected self-interference signal from the second communication signal.

2. The apparatus according to claim 1, wherein the processor is specifically configured to determine the reconstructed near-field reflected self-interference signal according to the near-field reflection channel parameter and the first communication signal, and subtract the reconstructed near-field reflected self-interference signal from the second communication signal.

3. The apparatus according to claim 1, wherein the apparatus further comprises:

a coupler, configured to sample a signal to be sent, to obtain a self-interference radio frequency reference signal, wherein

the processor is specifically configured to determine the reconstructed near-field reflected self-interference signal according to the near-field reflection channel parameter and the self-interference radio frequency reference signal, and subtract the reconstructed near-field reflected self-interference signal from the second communication signal.

4. The apparatus according to claim 1, wherein the transmitter is specifically configured to send the sounding signal by using a bandwidth greater than a bandwidth used for sending the first communication signal;

and

the processor is specifically configured to perform matched filtering on the near-field reflection signal, to obtain a filtered near-field reflection signal, and determine the near-field reflection channel parameter according to the filtered near-field reflection signal.

5. The apparatus according to claim 1, wherein the transmitter is specifically configured to send the sounding signal by using a bandwidth greater than or equal to a bandwidth used for sending the first communication signal;

and

the processor is specifically configured to determine, by using a super-resolution delay algorithm, the near-field reflection channel parameter corresponding to the near-field reflection signal.

6. The apparatus according to claim 5, wherein

the processor is specifically configured to determine the near-field reflection channel parameter by using the following formulas:

7. The apparatus according to claim 6, wherein when B is a conjugate matrix,

the processor is specifically configured to perform calculation through iteration from m=1 to m=M by using the following formula, to obtain (B+diag {w^(k)})⁻

1;

8. A method for canceling a self-interference signal in a communications system, wherein the method is executed by an apparatus supporting wireless full duplex, and the method comprises:

sending a sounding signal and a first communication signal, wherein a timeslot used for sending the sounding signal is different from a timeslot used for sending the first communication signal, and the sounding signal is a large time-bandwidth product signal;

receiving an input signal, wherein the input signal comprises a second communication signal sent by another apparatus and an echo signal that corresponds to the sounding signal and the first communication signal;

separating a near-field reflection signal corresponding to the sounding signal from the echo signal;

determining, based on the near-field reflection signal, a near-field reflection channel parameter;

determining, based on the near-field reflection channel parameter, a reconstructed near-field reflected self-interference signal; and

subtracting the reconstructed near-field reflected self-interference signal from the second communication signal, wherein the second communication signal is sent by another apparatus.

9. The method according to claim 8, wherein the determining, based on the near-field reflection channel parameter, a reconstructed near-field reflected self-interference signal comprises:

determining the reconstructed near-field reflected self-interference signal according to the near-field reflection channel parameter and the first communication signal.

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

sampling a signal to be sent, to obtain a self-interference radio frequency reference signal, wherein

the determining, based on the near-field reflection channel parameter, a reconstructed near-field reflected self-interference signal comprises;

determining the reconstructed near-field reflected self-interference signal according to the near-field reflection channel parameter and the self-interference radio frequency reference signal.

11. The method according to claim 8, wherein the sending a sounding signal comprises:

sending the sounding signal in a transmit timeslot in a sounding timeslot.

12. The method according to claim 11, wherein the sending a sounding signal comprises:

stopping sending the sounding signal in an idle timeslot in the sounding timeslot, wherein the idle timeslot comprises a first silent timeslot and a second silent timeslot; and

sending the first communication signal in a data transmission timeslot.

13. The method according to claim 12, wherein duration of the first silent timeslot is a maximum multi-path delay of the near-field reflection channel, and

a value of the second silent timeslot enables a delay of an echo component to exceed a sum of the duration of the first silent timeslot and duration of the second silent timeslot, and a power of the echo multi-path component is less than a preset threshold.