CN109511121B

CN109511121B - Interference elimination method and device

Info

Publication number: CN109511121B
Application number: CN201811552339.7A
Authority: CN
Inventors: 赵育仁; 余庆华; 徐彦超; 王泷
Original assignee: Spreadtrum Communications Shanghai Co Ltd
Current assignee: Spreadtrum Communications Shanghai Co Ltd
Priority date: 2018-12-18
Filing date: 2018-12-18
Publication date: 2023-04-07
Anticipated expiration: 2038-12-18
Also published as: CN109511121A

Abstract

The disclosure relates to an interference elimination method and device, the method comprises: when the wireless communication equipment prejudges that the occupied wireless channel changes, sending a self-training field; receiving the self-training field; and carrying out interference elimination processing on the received signal according to the self-training field. The wireless communication device transmits a self-training field for performing interference cancellation training when it is judged that an occupied wireless channel changes, and performs interference cancellation processing on a received signal according to the self-training field, thereby canceling interference in the received signal, and thus being capable of appropriately canceling interference in a wireless time-varying channel.

Description

Interference elimination method and device

Technical Field

The present disclosure relates to the field of communications technologies, and in particular, to an interference cancellation (interference cancellation) method and apparatus.

Background

In a wireless communication system, a Full Duplex (FD) technology can realize simultaneous and same-frequency bidirectional transmission of signals, that is, uplink data communication and downlink data communication are simultaneously realized on a single wireless channel.

When two communication nodes (communication devices) communicate with each other at the same time, a receiving antenna of the communication node receives not only a useful signal from an opposite communication node but also a self-interference signal which is a signal transmitted by the receiving antenna. Since the transmitting antenna and the receiving antenna of the communication node are relatively close to each other, the self-interference signal has a strength much higher than that of the useful signal from the opposite communication node, and thus the self-interference signal causes severe interference to the useful signal received from the opposite communication node.

The inventor has realized that the self-interference cancellation techniques in the prior art all assume that the channel is static or quasi-static, and thus the self-interference cancellation techniques in the prior art are only suitable for scenarios in which the channel is static or quasi-static, however, in practical wireless communication systems, there are scenarios in which the channel is not static or quasi-static, for example, there are cases in which there is relative movement between the transmitting antenna and its neighboring reflectors, and thus the self-interference cancellation techniques in the prior art may not be suitable.

Disclosure of Invention

In view of this, the present disclosure provides an interference cancellation method and apparatus.

According to an aspect of the present disclosure, an interference cancellation method is provided, which is applied to a wireless communication device, and includes:

when the wireless communication equipment prejudges that the occupied wireless channel changes, sending a self-training field;

receiving the self-training field;

and carrying out interference elimination processing on the received signal according to the self-training field.

According to another aspect of the present disclosure, an interference cancellation apparatus is provided, which is applied to a wireless communication device, and includes:

a sending module, configured to send a self-training field when a wireless channel occupied by the wireless communication device is predicted to change;

a receiving module, configured to receive the self-training field;

and the processing module is used for carrying out interference elimination processing on the received signals according to the self-training field.

The technical scheme provided by the embodiment of the disclosure can have the following beneficial effects: when the wireless communication device judges that the wireless channel occupied by the wireless communication device possibly changes, the wireless communication device sends a self-training field for carrying out interference elimination training, and carries out interference elimination processing on the received signal according to the self-training field so as to eliminate the interference in the received signal, thereby being capable of properly eliminating the interference in the wireless time-varying channel.

Other features and aspects of the present disclosure will become apparent from the following detailed description of exemplary embodiments, which proceeds with reference to the accompanying drawings.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate exemplary embodiments, features, and aspects of the disclosure and, together with the description, serve to explain the principles of the disclosure.

Fig. 1 is a diagram illustrating a wireless network in accordance with an example embodiment.

Fig. 2 is a flow chart illustrating a method of interference cancellation in accordance with an example embodiment.

Fig. 3 is a timing diagram illustrating processing by a wireless communication device in accordance with an example embodiment.

Fig. 4 is a diagram illustrating the structure of an RTS/CTS frame, according to an example embodiment.

Fig. 5 is a block diagram illustrating a structure of an RTS/CTS frame according to an example embodiment.

Fig. 6 is a block diagram illustrating a structure of an RTS/CTS frame according to an example embodiment.

Fig. 7 is a block diagram illustrating a structure of an RTS/CTS frame according to an example embodiment.

Fig. 8 is a block diagram illustrating a structure of an RTS/CTS frame according to an example embodiment.

Fig. 9 is a block diagram illustrating a structure of an RTS/CTS frame according to an example embodiment.

Fig. 10 is a block diagram illustrating a structure of an RTS/CTS frame according to an example embodiment.

Fig. 11 is a block diagram illustrating a structure of an RTS/CTS frame according to an example embodiment.

Fig. 12 is a timing diagram illustrating processing by a wireless communication device according to an example embodiment.

Fig. 13 is a timing diagram illustrating processing by a wireless communication device according to an example embodiment.

Fig. 14 is a timing diagram illustrating a process performed by a wireless communication device according to an example embodiment.

Fig. 15 is a timing diagram illustrating processing by a wireless communication device according to an example embodiment.

Fig. 16 is a timing diagram illustrating a process performed by a wireless communication device according to an example embodiment.

Fig. 17 is a block diagram illustrating an interference cancellation arrangement according to an example embodiment.

Fig. 18 is a block diagram illustrating a hardware structure of an apparatus for interference cancellation according to an example embodiment.

Detailed Description

Various exemplary embodiments, features and aspects of the present disclosure will be described in detail below with reference to the accompanying drawings. In the drawings, like reference numbers can indicate functionally identical or similar elements. While the various aspects of the embodiments are presented in drawings, the drawings are not necessarily drawn to scale unless specifically indicated.

The word "exemplary" is used exclusively herein to mean "serving as an example, embodiment, or illustration. Any embodiment described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments.

Furthermore, in the following detailed description, numerous specific details are set forth in order to provide a better understanding of the present disclosure. It will be understood by those skilled in the art that the present disclosure may be practiced without some of these specific details. In some instances, methods, means, elements and circuits that are well known to those skilled in the art have not been described in detail so as not to obscure the present disclosure.

For convenience of explanation, some terms related to the present disclosure will be first explained below.

An Access Point (AP) may also be referred to as a wireless Access Point, a bridge, a hotspot, and the like, and may Access a server or a communication network.

A Station (STA) may be a wireless communication terminal or a mobile terminal, such as a mobile phone (may be referred to as a "cellular" phone) supporting a wireless fidelity (WiFi) communication function, a tablet computer supporting a WiFi communication function, a computer with a wireless communication function, and the like.

And a Request To Send (RTS) frame, which indicates the channel time to be occupied by the wireless communication device for subsequent data transmission in the Duration (Duration) field of the RTS frame, so that the wireless communication device capable of receiving the RTS frame does not occupy the channel in the time.

And a Clear To Send (CTS) frame, and a channel time corresponding to the Duration field of the RTS frame is set in the Duration field of the CTS frame so that a wireless communication device that has not received the RTS frame but can receive the CTS frame does not occupy the channel during the time.

Fig. 1 is a diagram illustrating a wireless network in accordance with an example embodiment. As shown in fig. 1, the wireless network includes an AP and a plurality of STAs (e.g., mobile phones) within the coverage of the AP, such as STA-1, STA-2, and STA-3. Both the AP and the STA are provided with an antenna, which may be a receiving antenna for receiving data only, a transmitting antenna for transmitting data only, or a transceiving antenna for transceiving data. The AP and the STA may operate in full duplex mode. For convenience of description, only STA-1 is taken as an example for description, and the descriptions of AP, STA-2 and STA-3 are similar and will not be repeated herein.

It is assumed that the wireless channel occupied by STA-1 includes channel 1, STA-1 uses channel 1 to perform full duplex communication with the AP, and therefore, as described in the background, STA-1 receives, in addition to the above-mentioned useful signal, an interference signal transmitted by STA-1 to the AP using channel 1 on channel 1, and it is obvious that the interference signal interferes with the useful signal, and the interference may be referred to as "co-channel self-interference" or "in-band full duplex self-interference".

Assuming that the wireless channel occupied by STA-1 further includes channel 2 and

channels

1 and 2 are adjacent frequencies, channel 1 and channel 2 may be directly adjacent in frequency domain or not far apart, because

channels

1 and 2 are adjacent frequencies, other signals transmitted by STA-1 using channel 2 will leak onto adjacent channel 1, which results in STA-1 receiving the above mentioned other signals in addition to the above mentioned useful signals on channel 1, obviously, the other signals will interfere with the useful signals, and this interference may be referred to as "adjacent frequency self-interference". In other words, in the case where STA-1 occupies multiple wireless channels (e.g., multiple links exist for STA-1), there is also "adjacent frequency self-interference".

Thus, "self-interference" (self-interference) includes "same-frequency self-interference" and "adjacent-frequency self-interference". The term "self-interference" includes, but is not limited to, in-band Full Duplex (IBFD).

Methods for eliminating "self-interference" are proposed in the related art. However, after carefully investigating the methods for "self-interference" cancellation in the related art, the inventors found that these methods may require the assumption that the channel is static or quasi-static, and thus these methods may be applicable only to scenarios where the channel is approximately static. However, as is well known to those skilled in the art, a wireless channel has a time-varying characteristic, that is, an actual wireless channel may be a wireless time-varying channel, and thus the method in the related art may not be applicable to a scenario in which the channel is a wireless time-varying channel.

Based on this, the present disclosure provides an interference cancellation method and apparatus.

Fig. 2 is a flow chart illustrating an interference cancellation method applied to a wireless communication device, such as may be applied to the AP, STA-1, STA-2, or STA-3 of fig. 1, according to an example embodiment. As shown in fig. 2, the interference cancellation method may include the following steps.

In step S210, when the wireless communication device pre-determines that the occupied wireless channel changes, a self-training field is sent.

Alternatively, the wireless communication device may transmit the self-training field together when transmitting a signal to the peer wireless communication device, and of course, the wireless communication device may also transmit the self-training field directly without transmitting a signal to the peer wireless communication device.

In step S220, the self-training field is received.

In step S230, an interference cancellation process is performed on the received signal according to the self-training field (received self-training field).

In this embodiment, the wireless communication device transmits the self-training field(s) through one or more antennas and may receive the self-training field through the one or more antennas, although the wireless communication device may also receive the self-training field through other antennas. The self-training field is used for the wireless communication device to perform interference cancellation training by itself, that is, the wireless communication device may perform interference cancellation training according to the self-training field to adjust an interference cancellation coefficient used for performing interference cancellation processing on a received signal to a proper value (i.e., to perform parameter adaptation on an interference cancellation processing mechanism), and then directly use the adjusted interference cancellation coefficient to perform interference cancellation processing on the signal (data) when the signal is received.

For example, the self-training field may provide the wireless communication device with the information (which may also be referred to as data or information) and/or manner, etc. needed to perform interference cancellation training. The setting of the self-training field includes, but is not limited to, setting of a training length and/or setting of a training pattern, etc.

In this embodiment, the wireless communication device may set the self-training field according to the actual application requirement, or may select the self-training field satisfying the actual application requirement from the existing self-training fields. For example, if the interference cancellation training algorithm used requires only a short amount of time to complete the interference cancellation training, the wireless communication device may set a self-training field with a shorter training length or select a self-training field that may cause the interference cancellation training algorithm to take a shorter amount of time.

The inventors have realised that on recognising the problem of interference in a wireless time-varying channel: when the wireless communication equipment judges that the occupied wireless channel is possibly changed, the wireless communication equipment sends a signal to the opposite-end wireless communication equipment and simultaneously sends a self-training field, or directly sends the self-training field without sending the signal to the opposite-end wireless communication equipment, and fast parameter adaptation is carried out on an interference elimination processing mechanism according to the self-training field.

In one implementation, the inventors note that: the wireless communication device needs to perform a channel contention mechanism before performing full-duplex communication processing, if the full-duplex communication processing period is short, the transmission interval of the RTS/CTS frame is short, the transmission frequency of the RTS/CTS frame may be close to the change frequency of the wireless time-varying channel, and there is no interference in the transmission of the RTS/CTS frame because the transmission of the RTS/CTS frame is not full-duplex. On this basis, the inventors further think that: the self-training field is transmitted together with the RTS/CTS frame, that is, when a signal such as an RTS/CTS frame is transmitted to the counterpart wireless communication device, whereby, once the RTS/CTS frame is transmitted, the self-training field can be transmitted using the RTS/CTS frame, interference cancellation training is performed according to the received self-training field, and interference cancellation processing is performed on the received signal using the trained interference cancellation coefficient, so that interference cancellation processing can be performed in conformity with the wireless time-varying channel.

Illustratively, as shown in fig. 3, the self-training field may be sent when the wireless communication device predicts that the occupied wireless channel changes as follows: sending a self-training field using an RTS/CTS frame when the wireless channel changes, wherein the RTS/CTS frame carries the self-training field.

In this embodiment, the RTS/CTS frame includes a PHY Header (english: header) and Data (Data), wherein the Data field may be referred to as a Data field, and the RTS/CTS frame may carry a self-training field, which, in one implementation, is located between the PHY Header and the Data, as shown in fig. 4-7; in another implementation, the self-training field is located after the data, i.e., the self-training field is located at the end of the RTS/CTS frame, as shown in fig. 8-11.

It should be noted that, if the RTS/CTS frame is frequently sent after the self-training field is currently sent using the RTS/CTS frame, the self-training field is not carried in the frequently sent RTS/CTS frame. In other words, in one implementation, since the self-training field is transmitted using an RTS frame, if a transmission interval of a next RTS frame is less than a third time period, the next RTS frame may not carry the self-training field. In one implementation, since the self-training field is transmitted using a CTS frame, if a transmission interval of a next CTS frame is less than a fourth time period, the next CTS frame may not carry the self-training field. The present embodiment does not limit the magnitude relationship of the third and fourth time periods.

In another implementation, the inventors have noted, on recognizing the interference problem in wireless time-varying channels: if the full-duplex communication processing period is long, the transmission interval of the RTS/CTS frame is long, and the transmission frequency of the RTS/CTS frame may not be close to the variation frequency of the wireless time-varying channel, in which case it may not be appropriate to transmit the self-training field using only the RTS/CTS frame. On this basis, the inventors further conceived: the self-training field is transmitted during full-duplex communication processing (e.g., within an IBFD period), and when one wireless communication device of full-duplex communication transmits the self-training field, the other wireless communication device of the full-duplex communication is prohibited from transmitting data, whereby the self-training field is transmitted within a short period of time, interference cancellation training is performed according to the received self-training field, and interference cancellation processing is performed on a received signal using the trained interference cancellation coefficient, so that interference cancellation processing can be performed in adaptation to a wireless time-varying channel. Reference may be made specifically to the timing diagram of the processing performed by the wireless communication apparatus shown in fig. 12.

Illustratively, as shown in fig. 13-14, the self-training field may be sent when the wireless communication device predicts that the occupied wireless channel changes as follows: when the wireless channel is changed, if a signal transmission period is greater than a predetermined period, using mid-amble codes in an Orthogonal Frequency Division Multiplexing (OFDM) data packet to transmit the self-training field in the signal transmission period, wherein when the self-training field is transmitted, the wireless communication device at the opposite end of the wireless communication device does not transmit signals. The mid-amble code can also be selected to be shared with a mid-amble code for overcoming doppler effect for the receiving end, i.e. the same mid-amble code can be used as self-interference cancellation parameter adaptation for the transmitting end and also as channel estimation update for the receiving end.

For example, as shown in fig. 15 to 16, the self-training field may be sent when the wireless communication device predicts that the occupied wireless channel changes as follows: when the wireless channel is changed, if a signal transmission period is greater than a predetermined period and a plurality of data packets are transmitted in the signal transmission period, transmitting the self-training field in a gap for transmitting the plurality of data packets by using a training data packet, wherein when the self-training field is transmitted, a wireless communication device at a peer end of the wireless communication device does not transmit a signal. The training data packet is a trigger frame, and the trigger frame carries time synchronization information and a self-training field of the full-duplex data packet.

In this embodiment, the signal transmission period corresponds to the full-duplex communication processing period (for example, the IBFD period in fig. 12) in the foregoing, and the wireless communication apparatus may set a predetermined period according to the change frequency of the wireless time-varying channel, and determine whether the signal transmission period is greater than the set predetermined period, and if the signal transmission period is determined to be greater than the set predetermined period, it indicates that the signal transmission period is longer and the self-training field needs to be sent in the signal transmission period.

The wireless communication apparatus may determine the number of packets transmitted in a signal transmission period, may transmit the self-training field in the signal transmission period if the number is 1, may transmit the self-training field in an interval between any two packets if the number is plural, and may transmit the number of the self-training fields to be 1 or more.

In one implementation, the self-training field may also be sent periodically.

In this embodiment, the self-training field is sent again every time a first time period elapses since the self-training field is sent. The first time period is a period sent from the training field.

In one implementation, the self-training field may be further sent again if a signal needs to be transmitted when a second time period elapses since the self-training field is sent.

The present embodiment does not limit the magnitude relationship of the first to fourth time periods.

In one implementation, the step S230 may include:

performing interference cancellation processing on the received signal according to the self-training field only (see fig. 4 and 8); or

Performing interference cancellation processing on the received signal according to the self-training field and the channel estimation field (see fig. 5 and 9); or

Performing interference cancellation processing on the received signal according to the self-training field, the channel estimation field, and a physical layer (PHY) header of the RTS/CTS frame (see FIGS. 6 and 10); or

Performing interference cancellation processing on the received signal according to the self-training field, the channel estimation field, a physical layer (PHY) header of the RTS/CTS frame, and a data field of the RTS/CTS frame (see FIGS. 7 and 11).

In this embodiment, when it is determined that a wireless channel occupied by the wireless communication device may change, the wireless communication device sends a self-training field for performing interference cancellation training, and performs interference cancellation processing on a received signal according to the self-training field, so as to cancel interference in the received signal, thereby being capable of appropriately canceling interference in a wireless time-varying channel.

Fig. 17 is a block diagram illustrating an interference cancellation arrangement according to an example embodiment. As shown in fig. 17, the apparatus may include a transmitting module 310, a receiving module 320, and a processing module 330.

The sending module 310 is configured to send a self-training field when the wireless communication device prejudges that the occupied wireless channel changes.

A receiving module 320, configured to receive the self-training field.

The processing module 330 is connected to the transmitting module 310 and the receiving module 320, and configured to perform interference cancellation processing on the received signal according to the self-training field.

In a possible implementation manner, the sending module 310 is further configured to:

and after the self-training field is transmitted, the self-training field is transmitted again every first time period.

and under the condition that a second time period passes since the self-training field is transmitted, if a signal needs to be transmitted, the self-training field is transmitted again.

In one possible implementation, the sending module 310 is configured to:

sending the self-training field using a Request To Send (RTS) frame when the wireless channel changes, wherein the RTS frame carries the self-training field.

In one possible implementation, the processing module 330 is configured to:

performing interference cancellation processing on the received signal only according to the self-training field; or

Carrying out interference elimination processing on the received signal according to the self-training field and the channel estimation field; or

Performing interference cancellation processing on the received signal according to the self-training field, the channel estimation field and a physical layer (PHY) header of the RTS frame; or

And carrying out interference elimination processing on the received signal according to the self-training field, the channel estimation field, the physical layer (PHY) header of the RTS frame and the data field of the RTS frame.

In one possible implementation, the self-training field is located after a physical layer PHY header of the RTS frame or at the end of the RTS frame.

In a possible implementation manner, since the self-training field is sent using an RTS frame, if a sending interval of a next RTS frame is smaller than a third time period, the next RTS frame may not carry the self-training field.

In one possible implementation, the sending module 310 is configured to:

sending the self-training field using a clear-to-send (CTS) frame when the wireless channel changes, wherein the CTS frame carries the self-training field.

In one possible implementation, the processing module 330 is configured to:

Performing interference cancellation processing on the received signal according to the self-training field, the channel estimation field and a physical layer (PHY) header of the CTS frame; or

And carrying out interference elimination processing on the received signal according to the self-training field, the channel estimation field, the physical layer (PHY) header of the CTS frame and the data section of the CTS frame.

In one possible implementation, the self-training field is located after a physical layer PHY header of the CTS frame or at the end of the CTS frame.

In one possible implementation, since the self-training field is transmitted using a CTS frame, if a transmission interval of a next CTS frame is less than a fourth time period, the next CTS frame does not carry the self-training field.

In one possible implementation, the sending module 310 is configured to:

when the wireless channel is changed, if a signal transmission period is greater than a predetermined period, using mid-amble codes in an Orthogonal Frequency Division Multiplexing (OFDM) data packet to transmit the self-training field in the signal transmission period, wherein when the self-training field is transmitted, opposite-end communication equipment of the wireless communication equipment does not transmit signals.

In one possible implementation, the sending module 310 is configured to:

when the wireless channel is changed, if a signal transmission period is greater than a predetermined period and a plurality of data packets are transmitted in the signal transmission period, using a self-training data packet to transmit the self-training field in a gap for transmitting the plurality of data packets, wherein when the self-training field is transmitted, a peer communication device of the wireless communication device does not transmit a signal.

In a possible implementation manner, the self-training data packet is a trigger frame, and the trigger frame carries time synchronization information of a full-duplex data packet and the self-training field.

In one possible implementation, the interference in the received signal includes in-band full duplex self-interference and adjacent frequency self-interference.

With regard to the apparatus in the above embodiment, the specific manner in which each module performs the operation has been described in detail in the embodiment related to the method, and will not be described in detail here.

Fig. 18 is a block diagram illustrating a hardware structure of an apparatus for interference cancellation according to an example embodiment. Referring to fig. 18, the apparatus 900 may include a processor 901, a machine-readable storage medium 902 having stored thereon machine-executable instructions. The processor 901 and the machine-readable storage medium 902 may communicate via a system bus 903. Also, the processor 901 performs the interference cancellation method described above by reading machine executable instructions in the machine readable storage medium 902 corresponding to the logic of interference cancellation.

The machine-readable storage medium 902 referred to herein may be any electronic, magnetic, optical, or other physical storage device that can contain or store information such as executable instructions, data, and the like. For example, the machine-readable storage medium may be: a RAM (random Access Memory), a volatile Memory, a non-volatile Memory, a flash Memory, a storage drive (e.g., a hard drive), a solid state drive, any type of storage disk (e.g., an optical disk, a dvd, etc.), or similar storage medium, or a combination thereof.

Having described embodiments of the present disclosure, the foregoing description is intended to be exemplary, not exhaustive, and not limited to the disclosed embodiments. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The terms used herein were chosen in order to best explain the principles of the embodiments, the practical application, or technical improvements to the techniques in the marketplace, or to enable others of ordinary skill in the art to understand the embodiments disclosed herein.

Claims

1. An interference cancellation method applied to a wireless communication device, the method comprising:

receiving the self-training field;

carrying out interference elimination processing on the received signals according to the self-training word;

wherein the interference in the received signal comprises in-band full-duplex self-interference and adjacent-frequency self-interference.

2. The method of claim 1, further comprising:

3. The method of claim 1 or 2, further comprising:

4. The method according to claim 1 or 2, wherein when the wireless communication device prejudges that the occupied wireless channel changes, sending a self-training field comprises:

5. The method of claim 4, wherein performing interference cancellation processing on the received signal according to the self-training field comprises:

6. The method of claim 4, wherein the self-training field is located after a physical layer (PHY) header of the RTS frame or at an end of the RTS frame.

7. The method of claim 4, further comprising:

and if the sending interval of the next RTS frame is less than a third time period since the self-training field is sent by using the RTS frame, the next RTS frame does not carry the self-training field.

8. The method according to claim 1 or 2, wherein when the wireless communication device prejudges that the occupied wireless channel changes, sending a self-training field comprises:

9. The method of claim 8, wherein performing interference cancellation processing on the received signal according to the self-training field comprises:

10. The method of claim 8, wherein the self-training field is located after a physical layer (PHY) header of the CTS frame or at an end of the CTS frame.

11. The method of claim 8, further comprising:

and if the sending interval of the next CTS frame is less than a fourth time period since the self-training field is sent by using the CTS frame, the next CTS frame does not carry the self-training field.

12. The method according to claim 1 or 2, wherein when the wireless communication device prejudges that the occupied wireless channel changes, sending a self-training field comprises:

when the wireless channel is changed, if a signal transmission period is greater than a predetermined period, using mid-amble codes in an Orthogonal Frequency Division Multiplexing (OFDM) data packet to transmit the self-training field in the signal transmission period, wherein when the self-training field is transmitted, the wireless communication device at the opposite end of the wireless communication device does not transmit signals.

13. The method according to claim 1 or 2, wherein when the wireless communication device prejudges that the occupied wireless channel changes, sending a self-training field comprises:

when the wireless channel is changed, if a signal transmission period is greater than a predetermined period and a plurality of data packets are transmitted in the signal transmission period, transmitting the self-training field in a gap for transmitting the plurality of data packets by using a self-training data packet, wherein when the self-training field is transmitted, a wireless communication device at a peer end of the wireless communication device does not transmit a signal.

14. The method of claim 13, wherein the self-training packet is a trigger frame, and wherein the trigger frame carries the self-training field and time synchronization information of a full-duplex packet.

15. An interference cancellation apparatus applied to a wireless communication device, the apparatus comprising:

a sending module, configured to send a self-training field when the wireless communication device prejudges that an occupied wireless channel changes;

a receiving module, configured to receive the self-training field;

the processing module is used for carrying out interference elimination processing on the received signals according to the self-training field;

16. The apparatus of claim 15, wherein the sending module is further configured to:

17. The apparatus of claim 15 or 16, wherein the sending module is further configured to:

18. The apparatus of claim 15 or 16, wherein the sending module is configured to:

19. The apparatus of claim 18, wherein the processing module is configured to:

20. The apparatus of claim 18, wherein the self-training field is located after a physical layer (PHY) header of the RTS frame or at an end of the RTS frame.

21. The apparatus of claim 18,

22. The apparatus of claim 15 or 16, wherein the transmitting module is configured to:

23. The apparatus of claim 22, wherein the processing module is configured to:

24. The apparatus of claim 22, wherein the self-training field is located after a physical layer (PHY) header of the CTS frame or at an end of the CTS frame.

25. The apparatus of claim 22,

26. The apparatus of claim 15 or 16, wherein the transmitting module is configured to:

27. The apparatus of claim 15 or 16, wherein the transmitting module is configured to:

28. The apparatus of claim 27, wherein the self-training packet is a trigger frame, and wherein the trigger frame carries time synchronization information and the self-training field of a full-duplex packet.