Communication method and communication apparatus

Abstract

A communication method and a communication apparatus, which can be applied to a WLAN system supporting 802.11 series protocols such as a next-generation WiFi protocol of IEEE 802.11ax, i.e., 802.11be, 802.11bn, and the next generation of 802.11bn, and can also be applied to a UWB-based wireless personal area network system and sensing system. In the method, when a first station detects exchange of unavailability information by an OBSS station, the first station can enable NPCA based on a PPDU length, that is, when detecting a PPDU that satisfies a condition for triggering NPCA, the first station switches from a primary channel to an NPCA primary channel, and switches back to the primary channel on the basis of an end time of the PPDU, thereby enabling timely switching back to the primary channel for channel contention, avoiding waste of transmission resources of the primary channel.

Description

[0001] This application claims priority to Chinese Patent Application No. 202510346901.4, filed with the China National Intellectual Property Administration on March 21, 2025 and entitled "COMMUNICATION METHOD AND COMMUNICATION APPARATUS", which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0002] This application relates to the communication field, and more specifically, to a channel access method and an apparatus. BACKGROUND

[0003] In a wireless local area network (wireless local area network, WLAN), when an access point (access point, AP) communicates with a non-access point station (non-AP station, non-AP STA), access is usually performed on a primary channel, which is referred to as a primary channel access mechanism. However, when the primary channel is busy and a non-primary channel is idle, a station (for example, the AP or the non-AP STA) determines, according to the primary channel access mechanism, that an entire channel is unavailable, wasting resources of the non-primary channel. Therefore, a non-primary channel access (non-primary channel access, NPCA) mechanism is further proposed in a standard. When the primary channel is busy, the station may switch to a sub-channel of a non-primary channel to perform channel contention, so as to perform communication on the non-primary channel.

[0004] However, an existing NPCA mechanism may cause problems such as a resource waste and a transmission failure. SUMMARY

[0005] This application provides a communication method and a communication apparatus, to improve resource utilization.

[0006] According to a first aspect, a communication method is provided. The method may be applied to a first station. For example, the method may be performed by the first station, or may be performed by a component (for example, a chip, a circuit, or a chip system) of the first station.

[0007] The method includes: receiving a first frame from a second station on a first primary channel, where the first frame is used to query or solicit (solicit) unavailability information of a station associated with the second station, or the first frame is used to carry unavailability information of the second station; and a basic service set (basic service set, BSS) to which the second station belongs and a BSS to which the first station belongs are overlapping basic service sets (overlapping basic service set, OBSS) of each other; switching from the first primary channel to a second primary channel when a first physical layer protocol data unit (physical protocol data unit, PPDU) is detected in a transmission opportunity (transmission opportunity, TXOP) of the first frame and the first PPDU meets a condition for triggering NPCA, where the second primary channel is an NPCA primary channel, and the first PPDU is a PPDU sent by the second station or the station associated with the second station; and switching from the second primary channel to the first primary channel based on an end moment of the first PPDU.

[0008] Based on the foregoing solution, when the first station detects exchange of unavailability information by an OBSS station, the first station may enable PPDU length-based NPCA. To be specific, when a PPDU that meets a condition for triggering NPCA is detected, the first station switches from a primary channel to an NPCA primary channel, and switches back to the primary channel based on an end moment of the PPDU. In this way, the first station can switch back to the primary channel in time to perform channel contention, thereby avoiding a waste of transmission resources of the primary channel.

[0009] For example, the condition for triggering NPCA includes: Duration in which the first PPDU occupies the first primary channel is greater than a second threshold, and a channel occupied by the first PPDU does not overlap with the second primary channel.

[0010] For example, the TXOP of the first frame is a time period from a start moment of the first frame to an end indication that is of the TXOP and that is sent by the second station, or a time period from a start moment of the first frame to an end of countdown of an NAV timer set by the first station based on the first frame. Therefore, that the first PPDU is detected in the TXOP of the first frame may be replaced with: The first PPDU is detected before the first station receives the end indication of the TXOP, or the first PPDU is detected before countdown of the NAV timer set based on the first frame ends.

[0011] With reference to the first aspect, in some implementations, the first frame is a first initial control frame (initial control frame, ICF), and the first ICF meets at least one of the following conditions: The first ICF is a buffer status report poll (buffer status report poll, BSRP) frame, the BSRP frame includes response type indication information, and the response type indication information indicates that a response type of a response frame of the first frame is unavailability information feedback; or the first ICF is a BSRP frame, the BSRP frame includes ICF type indication information, and the ICF type indication information indicates that the first ICF is used to query unavailability information; or the first ICF is a BSRP frame, the BSRP frame includes a guard interval and high efficiency / ultra-high reliability long training field type (guard interval and high efficient / ultra high reliability long training field type, GI and HE / UHR-LTF type) field, and a value of the GI and HE / UHR-LTF type field is 3; or the first ICF is a BSRP frame, and the BSRP frame includes an uplink length (uplink length, UL length) field, and a value of the uplink length field is greater than a first threshold; or the first ICF is a BSRP frame, and the BSRP frame includes a carrier sense (carrier sounding, CS) required (required) field, and a value of the CS required field is 1.

[0012] Based on the foregoing solution, the first station may use information carried in the ICF as a determining condition, and no additional indication information is required. This can avoid a waste of a primary channel access opportunity, and more efficiently use resources of a non-primary channel.

[0013] In addition, the ICF may include more information, and is easier to decode. This can improve processing efficiency of the first station, and reduce power consumption.

[0014] With reference to the first aspect, in some implementations, the first frame is used to carry unavailability information of the second station, the first frame is a first initial control response (initial control response, ICR) frame, the first ICR frame is a multi-station block acknowledgment (multi-STA block ack, Multi-STA BA or Multi-STA BlockAck) frame, and the multi-station block acknowledgment frame meets at least one of the following conditions: The multi-station block acknowledgment frame includes the unavailability information of the second station; or a PPDU carrying the multi-station block acknowledgment frame is a non-high throughput (non-high throughput, non-HT) PPDU; or a value of a legacy signal length (legacy signal length, L-SIG LENGTH) field in a PPDU carrying the multi-station block acknowledgment frame is greater than a first threshold. For example, the L-SIG length field is located in a legacy signal (legacy signal, L-SIG) field in the PPDU, and may indicate a length of the PPDU. It should be understood that, in this application, the L-SIG field may also be referred to as a non-high throughput signal (non-HT signal) field. Therefore, the L-SIG length field may also be referred to as a non-high throughput signal length (non-HT signal length) field.

[0015] Based on the foregoing solution, the first station may use information carried in the ICR as a determining condition, and no additional indication information is required. This can avoid a waste of a primary channel access opportunity, and more efficiently use resources of a non-primary channel.

[0016] With reference to the first aspect, in some implementations, the first frame is a first ICF, the first ICF includes first indication information and / or second indication information, the first indication information indicates that there is a possibility of updating the TXOP of the first ICF, and the second indication information indicates that a type of NPCA performed in the TXOP of the first ICF by a station in an OBSS of the BSS to which the second station belongs is PPDU length-based NPCA.

[0017] Based on the foregoing solution, the first indication information is added to the first ICF, so that another station can clearly learn whether a TXOP of the second station may be shortened, and the first station can perform corresponding NPCA behavior based on the first indication information, thereby improving channel utilization efficiency. Alternatively, the second indication information is added to the first ICF, so that the first station can clearly learn, based on this indication bit, which type of NPCA should be performed. This avoids a waste of a primary channel access opportunity, and maximizes utilization efficiency of resources of the NPCA primary channel.

[0018] For example, in this implementation, the first ICF is a BSRP frame, the first indication information is carried in a common information field (Common Info) or special user information (Special User Info) field in the BSRP frame, and the second indication information is carried in the common information field or special user information field in the BSRP frame; or the first ICF is a multi-user request to send (multi-user request to send, MU-RTS) frame, the first indication information is carried in a common information field or special user information field in the MU-RTS frame, and the second indication information is carried in the common information field or special user information field in the MU-RTS frame.

[0019] Optionally, the first indication information further indicates whether the second station allows the first station to reset the network allocation vector (network allocation vector, NAV) timer set based on the first ICF.

[0020] Based on the foregoing solution, the first station can reset the NAV timer when the TXOP of the second station is shortened, thereby avoiding a waste of a primary channel access opportunity.

[0021] Optionally, the method further includes: determining, based on the first indication information, whether to perform opportunistic power save (opportunistic power save) in the TXOP of the first ICF.

[0022] Based on the foregoing solution, the first station may further determine whether to perform opportunistic power save in the TXOP of the first ICF. This can reduce power consumption without wasting a primary channel access opportunity.

[0023] With reference to the first aspect, in some implementations, the first PPDU includes first indication information and / or second indication information, the first indication information indicates that there is a possibility of updating a transmission opportunity TXOP of the first PPDU, the second indication information indicates that a type of NPCA performed in the TXOP of the first PPDU by a station in an OBSS of the BSS to which the second station belongs is PPDU length-based NPCA, and the TXOP of the first PPDU and the TXOP of the first frame are a same TXOP.

[0024] For example, the first indication information is carried in a preamble (preamble) of the first PPDU.

[0025] Based on the foregoing solution, the first indication information and / or the second indication information may be directly located in the first PPDU, so that when detecting the first PPDU, the first station can obtain the latest information about the TXOP, or directly obtain the type of NPCA, to help the first station make a decision in time.

[0026] With reference to the first aspect, in some implementations, the first station is a first non-AP STA. Before receiving the first frame, the method further includes: receiving second indication information from a first AP on the first primary channel, where the second indication information indicates that a type of NPCA of a non-AP STA associated with the first AP is PPDU length-based NPCA, and the non-AP STA associated with the first AP includes the first non-AP STA.

[0027] Based on the foregoing solution, the first AP may indicate, to the non-AP STA associated with the first AP, the type of NPCA that should be performed, so that the non-AP STA selects an appropriate NPCA solution, thereby improving resource utilization.

[0028] With reference to the first aspect, in some implementations, the first station is a first AP. Before receiving the first frame, the method further includes: sending second indication information on the first primary channel when determining that the second station enables a (dynamic unavailability operation DUO) mode, where the second indication information indicates that a type of NPCA of a non-AP STA associated with the first AP is PPDU length-based NPCA.

[0029] Based on the foregoing solution, the first AP may indicate, based on whether the OBSS station enables the DUO mode to the non-AP STA associated with the first AP, the type of NPCA that should be performed, so that the non-AP STA can perform appropriate NPCA, thereby avoiding a waste of resources of the primary channel.

[0030] For example, the second indication information is carried in a beacon frame and / or a probe response frame.

[0031] According to a second aspect, a communication method is provided. The method may be applied to a second station. For example, the method may be performed by the second station, or may be performed by a component (for example, a chip, a circuit, or a chip system) of the second station.

[0032] The method includes: generating first indication information, where the first indication information indicates whether there is a possibility of updating a first TXOP, and the first TXOP is a TXOP of a first ICF carrying the first indication information, or a TXOP of a first PPDU carrying the first indication information; and sending the first indication information on a first primary channel.

[0033] Based on the foregoing solution, the second station may indicate, to another station, whether a TXOP of the second station may be updated, for example, shortened, so that the latest information about the TXOP can be released in time, to facilitate a communication decision of the another station.

[0034] With reference to the second aspect, in some implementations, the first indication information is carried in the first ICF, the first ICF is a BSRP frame, and the first indication information is carried in a common information field or special user information field in the BSRP frame; or the first indication information is carried in the first ICF, the first ICF is an MU-RTS frame, and the first indication information is carried in a common information field or special user information field in the MU-RTS frame; or the first indication information is carried in a preamble of the first PPDU.

[0035] Optionally, the first indication information is carried in the first ICF, the first indication information further indicates whether the second station allows a first station to reset an NAV timer set based on the first ICF, and a BSS to which the second station belongs and a BSS to which the first station belongs are OBSSs of each other.

[0036] According to a third aspect, a communication method is provided. The method may be applied to a first station. For example, the method may be performed by the first station, or may be performed by a component (for example, a chip, a circuit, or a chip system) of the first station.

[0037] The method includes: receiving first indication information on a first primary channel, where the first indication information indicates whether there is a possibility of updating a first TXOP, and the first TXOP is a TXOP of a first ICF carrying the first indication information, or a TXOP of a first PPDU carrying the first indication information; and making a communication decision based on the first indication information.

[0038] Optionally, performing the communication decision based on the first indication information includes: determining, based on the first indication information, whether to perform NPCA, and / or determining a type of NPCA based on the first indication information.

[0039] According to a fourth aspect, a communication method is provided. The method may be applied to a first station. For example, the method may be performed by the first station, or may be performed by a component (for example, a chip, a circuit, or a chip system) of the first station.

[0040] The method includes: receiving second indication information on a first primary channel, where the second indication information indicates that a type of NPCA of the first station is PPDU length-based NPCA; switching from the first primary channel to a second primary channel when a first PPDU is detected and the first PPDU meets a condition for triggering NPCA, where the second primary channel is a non-primary channel access NPCA primary channel, the first PPDU is a PPDU sent by a second station or a station associated with a second station, and a BSS to which the second station belongs and a BSS to which the first station belongs are OBSSs of each other; and switching from the second primary channel to the first primary channel based on an end moment of the first PPDU.

[0041] Based on the foregoing solution, the first station may enable PPDU length-based NPCA based on the second indication information, so that the first station can switch back to the primary channel in time to perform channel contention, thereby avoiding a waste of transmission resources of the primary channel.

[0042] With reference to the fourth aspect, in some implementations, the first station is a first non-AP STA. Receiving the second indication information on the first primary channel includes: receiving the second indication information from a first AP on the first primary channel, where the second indication information indicates that a type of NPCA of a non-AP STA associated with the first AP is PPDU length-based NPCA, and the non-AP STA associated with the first AP includes the first non-AP STA.

[0043] Based on the foregoing solution, the first AP may indicate, to the non-AP STA associated with the first AP, the type of NPCA that should be performed, so that the non-AP STA selects an appropriate NPCA solution, thereby improving resource utilization.

[0044] For example, the second indication information is carried in a beacon frame and / or a probe response frame.

[0045] With reference to the fourth aspect, in some implementations, receiving the second indication information on the first primary channel includes: receiving a first ICF from the second station on the first primary channel, where the first ICF includes the second indication information, the second indication information indicates that a type of NPCA performed in a TXOP of the first ICF by a station in an OBSS of the BSS to which the second station belongs is PPDU length-based NPCA, the first PPDU is the PPDU sent by the second station or the station associated with the second station in the TXOP of the first ICF, and the station in the OBSS of the BSS to which the second station belongs includes the first station.

[0046] Based on the foregoing solution, the second station can explicitly indicate, to an OBSS station of the second station, the type of NPCA to be performed, so that the first station can enable the PPDU length-based NPCA, and the first station can switch back to the primary channel in time to perform channel contention, thereby avoiding a waste of transmission resources of the primary channel.

[0047] For example, the first ICF is a BSRP frame, and the second indication information is carried in a common information field or special user information field in the BSRP frame; or the first ICF is an MU-RTS frame, and the second indication information is carried in a common information field or special user information field in the MU-RTS frame.

[0048] With reference to the fourth aspect, in some implementations, receiving the second indication information on the first primary channel includes: receiving the first PPDU on the first primary channel, where a preamble of the first PPDU includes the second indication information, the second indication information indicates that a type of NPCA performed in a TXOP of the first PPDU by a station in an OBSS of the BSS to which the second station belongs is PPDU lengthbased NPCA, and the station in the OBSS of the BSS to which the second station belongs includes the first station.

[0049] According to a fifth aspect, a communication method is provided. The method includes: generating second indication information, where the second indication information indicates that a type of NPCA of a first station is PPDU length-NPCA; and sending the second indication information on a first primary channel.

[0050] With reference to the fifth aspect, in some implementations, the method is applied to a first AP, the first station is a first non-AP STA, the second indication information indicates that a type of NPCA of a non-AP STA associated with the first AP is PPDU length-based NPCA, and the non-AP STA associated with the first AP includes the first non-AP STA.

[0051] In an example of this implementation, sending the second indication information on the first primary channel includes: sending the second indication information on the first primary channel when determining that a second station enables a DUO mode, where a BSS to which the second station belongs and a BSS to which the first AP belongs are OBSSs of each other.

[0052] In another example of this implementation, sending the second indication information on the first primary channel includes: sending the second indication information on the first primary channel after determining that the first AP and a third AP have reached a Co-BF or CoSR agreement.

[0053] With reference to the fifth aspect, in some implementations, the method is applied to a second station. Sending the second indication information on the first primary channel includes: sending a first ICF on the first primary channel, where the first ICF includes the second indication information, the second indication information indicates that a type of NPCA performed in a TXOP of the first ICF by a station in an OBSS of a BSS to which the second station belongs is PPDU length-based NPCA, and the station in the OBSS of the BSS to which the second station belongs includes the first station.

[0054] With reference to the fifth aspect, in some implementations, the method is applied to a second station. Sending the second indication information on the first primary channel includes: sending a first PPDU on the first primary channel, where a preamble of the first PPDU includes the second indication information, the second indication information indicates that a type of NPCA performed in a TXOP of the first PPDU by a station in an OBSS of a BSS to which the second station belongs is PPDU length-based NPCA, and the station in the OBSS of the BSS to which the second station belongs includes the first station.

[0055] According to a sixth aspect, a communication method is provided. The method may be applied to a first station. For example, the method may be performed by the first station, or may be performed by a component (for example, a chip, a circuit, or a chip system) of the first station.

[0056] The method includes: receiving a first frame from a second station on a first primary channel, where the first frame includes an unavailability start moment, and a BSS to which the second station belongs and a BSS to which the first station belongs are OBSSs of each other; and switching from the first primary channel to a second primary channel when a first PPDU is detected in a TXOP of the first frame and the first PPDU meets a condition for NPCA, where the second primary channel is an NPCA primary channel, and the first PPDU is a PPDU sent by the second station or a station associated with the second station; and switching from the second primary channel to the first primary channel based on the unavailability start moment.

[0057] Based on the foregoing solution, the first station may switch from the NPCA primary channel back to the primary channel before the unavailability start moment, thereby more efficiently using the NPCA primary channel. Specifically, even if the second station shortens the TXOP due to a DUO, a shortened part also belongs to an unavailability time period of an OBSS station. Therefore, the primary channel is still always occupied by the OBSS before the unavailability start moment of the OBSS station, and the first station can still perform NPCA in this time period. However, the first station switches back to the primary channel at the unavailability start moment of the OBSS station, so that the first station can learn of a status of the primary channel in time, and the first station can also contend for the primary channel earlier when an OBSS TXOP is terminated in advance.

[0058] For example, the first frame is a first ICR frame, the first ICR frame is a multi-station block acknowledgment frame, and a PPDU carrying the multi-station block acknowledgment frame is a non-HT PPDU.

[0059] According to a seventh aspect, a communication method is provided. The method may be applied to a first station. For example, the method may be performed by the first station, or may be performed by a component (for example, a chip, a circuit, or a chip system) of the first station.

[0060] The method includes: receiving a first frame from a second station on a first primary channel, where the first frame is used to query unavailability information of a station associated with the second station, or the first frame is used to carry unavailability information of the second station; and a BSS to which the second station belongs and a BSS to which the first station belongs are OBSSs of each other; and staying on the first primary channel in a TXOP of the first frame, that is, not performing NPCA.

[0061] Based on the foregoing solution, the first station can always stay on the first primary channel in the TXOP of the first frame. This can avoid a waste of resources of the primary channel, that is, can avoid a waste of a primary channel access opportunity because the first station switches to an NPCA primary channel when a TXOP of the second station ends in advance.

[0062] According to an eighth aspect, a communication method is provided. The method may be applied to a first station. For example, the method may be performed by the first station, or may be performed by a component (for example, a chip, a circuit, or a chip system) of the first station.

[0063] The method includes: receiving a second frame from a second station on a first primary channel, where the second frame is used to transmit control information in a first multi-AP coordination procedure, the first multi-AP coordination procedure is a coordinated spatial reuse (coordinated spatial reuse, Co-SR, or CoSR, or COSR, or CSR, or co-SR) procedure or a coordinated beamforming (coordinated beamforming, Co-BF, or CoBF, or COBF, or CBF, or co-BF) procedure, and the second station participates in the first multi-AP coordination procedure; and switching from the first primary channel to a second primary channel when the first station does not participate in the first multi-AP coordination procedure and it is detected that a first PPDU meets a condition for triggering NPCA, where the second primary channel is an NPCA primary channel, the first PPDU is a downlink data PPDU in the first multi-AP coordination procedure, and a BSS to which the second station belongs and a BSS to which the first station belongs are OBSSs of each other; or staying on the first primary channel in a TXOP of the first multi-AP coordination procedure when the first station participates in the first multi-AP coordination procedure and the second frame or a first PPDU is detected, that is, not performing NPCA.

[0064] Based on the foregoing solution, when the first station does not participate in a first multi-AP coordination procedure that is being performed by an OBSS station, the first station may start, after detecting a downlink data PPDU of the OBSS station, to switch to the NPCA primary channel. When the first station participates in the first multi-AP coordination procedure, the first station does not perform NPCA in the TXOP of the first multi-AP coordination procedure. In other words, an OBSS control frame or the downlink data PPDU in the multi-AP coordination procedure in which the first station participates cannot trigger the first station to switch to the NPCA primary channel. The first station switches to the NPCA primary channel only when detecting a downlink data PPDU in a multi-AP coordination procedure in which the first station does not participate. This can prevent the first station from switching to the NPCA primary channel when necessary, thereby avoiding a transmission failure in the multi-AP coordination procedure in which the first station participates, and avoiding a waste of transmission resources of the primary channel.

[0065] For example, the second frame is a control frame before the downlink data PPDU in the first multi-AP coordination procedure. For example, the second frame is any one of the following: an ICF in the Co-BF procedure, an ICR frame in the Co-BF procedure, an ICF in the Co-SR procedure, or an ICR frame in the Co-SR procedure.

[0066] With reference to the eighth aspect, in some implementations, the method further includes: switching from the second primary channel to the first primary channel based on an end moment of a TXOP of the first multi-AP coordination procedure; or switching from the second primary channel to the first primary channel based on an end moment of the first PPDU.

[0067] Based on the foregoing solution, the first station may switch back to the first primary channel based on the end moment of the TXOP of the first multi-AP coordination procedure. This can prevent the first station from frequently performing channel switching, thereby reducing overheads. Alternatively, the first station may switch back to the first primary channel based on the end moment of the first PPDU, so that the first station can participate in primary channel contention in time, thereby maximizing utilization of resources of the primary channel.

[0068] With reference to the eighth aspect, in some implementations, the first PPDU includes N basic service set colors BSS colors, and the N BSS colors include a BSS color of a basic service set BSS to which a station participating in the first multi-AP coordination procedure belongs. When the first station does not participate in the first multi-AP coordination procedure, all the N BSS colors are different from a BSS color of the BSS to which the first station belongs; or when the first station does not participate in the first multi-AP coordination procedure, the N BSS colors include a BSS color of the BSS to which the first station belongs. N is an integer greater than or equal to 2.

[0069] Based on the foregoing solution, the first station may determine, based on the BSS color included in the first PPDU, whether the first station participates in the first multi-AP coordination procedure. In this way, the first station can determine an appropriate NPCA solution, so that the first multi-AP coordination procedure can be normally performed.

[0070] For example, switching from the first primary channel to the second primary channel includes: after detecting a universal signal field (universal signal field, U-SIG) of the first PPDU, starting to switch from the first primary channel to the second primary channel.

[0071] Based on the foregoing solution, because the U-SIG field and a field preceding the U-SIG field include necessary information for determining whether to perform NPCA, for example, an L-SIG field preceding the U-SIG field includes a length field, and the U-SIG field includes a TXOP field and a BSS color field, after detecting the U-SIG field in the first PPDU, the first station starts to switch, to obtain the necessary information for determining whether to perform NPCA, to help the first station make a decision.

[0072] With reference to the eighth aspect, in some implementations, the first station is a first AP. Before receiving the second frame, the method further includes: sending second indication information on the first primary channel after determining that the first AP and a third AP have reached a Co-BF or Co-SR agreement, where the second indication information indicates that a type of NPCA of a non-AP STA associated with the first AP is PPDU length-based NPCA.

[0073] For example, when the first AP does not participate in the first multi-AP coordination procedure, the third AP also does not participate in the first multi-AP coordination procedure, and both the first AP and the third AP may participate in a second multi-AP coordination procedure.

[0074] For example, when the first AP participates in the first multi-AP coordination procedure, the third AP may be a second AP. In other words, both the first AP and the third AP participate in the first multi-AP coordination procedure.

[0075] With reference to the eighth aspect, in some implementations, the first station is a first non-AP STA. Before receiving the second frame, the method further includes: receiving second indication information from a first AP on the first primary channel, where the second indication information indicates that a type of NPCA of a non-AP STA associated with the first AP is PPDU length-based NPCA, and the non-AP STA associated with the first AP includes the first non-AP STA.

[0076] According to a ninth aspect, a communication method is provided. The method may be applied to a first station. For example, the method may be performed by the first station, or may be performed by a component (for example, a chip, a circuit, or a chip system) of the first station.

[0077] The method includes: switching from a first primary channel to a second primary channel when a first PPDU is detected on the first primary channel and the first PPDU meets a condition for triggering NPCA, where the second primary channel is an NPCA primary channel, the first PPDU is a PPDU sent by a second station or a station associated with a second station, and a BSS to which the second station belongs and a BSS to which the first station belongs are OBSSs of each other; and switching from the second primary channel to the first primary channel based on an end moment of the first PPDU.

[0078] Based on the foregoing solution, the first station may always enable PPDU lengthbased NPCA, so that the first station can switch back to the primary channel in time to perform channel contention, thereby avoiding a waste of transmission resources of the primary channel.

[0079] With reference to the ninth aspect, in some implementations, the first station is a first non-AP STA. Before detecting the first PPDU, the method further includes: receiving second indication information from a first AP on the first primary channel, where the second indication information indicates that a type of NPCA of a non-AP STA associated with the first AP is PPDU length-based NPCA, and the non-AP STA associated with the first AP includes the first non-AP STA.

[0080] With reference to the ninth aspect, in some implementations, the first station is a first AP. Before detecting the first PPDU, the method further includes: sending second indication information on the first primary channel when determining that the second station enables a DUO mode, where the second indication information indicates that a type of NPCA of a non-AP STA associated with the first AP is PPDU length-based NPCA.

[0081] With reference to the ninth aspect, in some implementations, the first station is a first AP. Before detecting the first PPDU, the method further includes: sending second indication information on the first primary channel after determining that the first AP and a third AP have reached a Co-BF or Co-SR agreement, where the second indication information indicates that a type of NPCA of a non-AP STA associated with the first AP is PPDU length-based NPCA.

[0082] According to a tenth aspect, a communication apparatus is provided. The apparatus may be a first station, or may be a component (for example, a chip, a circuit, or a chip system) of a first station. The apparatus may have a function of implementing the first aspect. For example, the apparatus includes a corresponding module, unit, or means (means) for performing the related operation in the first aspect. The module, unit, or means may be specifically implemented by software, or hardware, or a combination of software and hardware.

[0083] Specifically, the apparatus includes: a transceiver unit, configured to receive a first frame from a second station on a first primary channel, where the first frame is used to query unavailability information of a station associated with the second station, or the first frame is used to carry unavailability information of the second station; and a BSS to which the second station belongs and a BSS to which the first station belongs are OBSSs of each other; and a processing unit, configured to switch from the first primary channel to a second primary channel when a first PPDU is detected in a TXOP of the first frame and the first PPDU meets a condition for triggering NPCA, where the second primary channel is an NPCA primary channel, and the first PPDU is a PPDU sent by the second station or the station associated with the second station. The processing unit is further configured to switch from the second primary channel to the first primary channel based on an end moment of the first PPDU.

[0084] Optionally, the processing unit is further configured to perform opportunistic power save in a TXOP of a first ICF based on the first indication information.

[0085] With reference to the tenth aspect, in some implementations, the first station is a first non-AP STA. Before receiving the first frame, the transceiver unit is further configured to receive second indication information from a first AP on the first primary channel, where the second indication information indicates that a type of NPCA of a non-AP STA associated with the first AP is PPDU length-based NPCA, and the non-AP STA associated with the first AP includes the first non-AP STA.

[0086] With reference to the tenth aspect, in some implementations, the first station is a first AP. Before receiving the first frame, the transceiver unit is further configured to send second indication information on the first primary channel when determining that the second station enables a DUO mode, where the second indication information indicates that a type of NPCA of a non-AP STA associated with the first AP is PPDU length-based NPCA.

[0087] According to an eleventh aspect, a communication apparatus is provided. The apparatus may be a second station, or may be a component (for example, a chip, a circuit, or a chip system) of a second station. The apparatus may have a function of implementing the second aspect. For example, the apparatus includes a corresponding module, unit, or means for performing the related operation in the second aspect. The module, unit, or means may be specifically implemented by software, or hardware, or a combination of software and hardware.

[0088] Specifically, the apparatus includes: a processing unit, configured to generate first indication information, where the first indication information indicates whether there is a possibility of updating a first TXOP, and the first TXOP is a TXOP of a first ICF carrying the first indication information, or a TXOP of a first PPDU carrying the first indication information; and a transceiver unit, configured to send the first indication information on a first primary channel.

[0089] According to a twelfth aspect, a communication apparatus is provided. The apparatus may be a first station, or may be a component (for example, a chip, a circuit, or a chip system) of a first station. The apparatus may have a function of implementing the third aspect. For example, the apparatus includes a corresponding module, unit, or means for performing the related operation in the third aspect. The module, unit, or means may be specifically implemented by software, or hardware, or a combination of software and hardware.

[0090] Specifically, the apparatus includes: a transceiver unit, configured to receive first indication information on a first primary channel, where the first indication information indicates whether there is a possibility of updating a first TXOP, and the first TXOP is a TXOP of a first ICF carrying the first indication information, or a TXOP of a first PPDU carrying the first indication information; and a processing unit, configured to make a communication decision based on the first indication information.

[0091] According to a thirteenth aspect, a communication apparatus is provided. The apparatus may be a first station, or may be a component (for example, a chip, a circuit, or a chip system) of a first station. The apparatus may have a function of implementing the fourth aspect. For example, the apparatus includes a corresponding module, unit, or means for performing the related operation in the fourth aspect. The module, unit, or means may be specifically implemented by software, or hardware, or a combination of software and hardware.

[0092] Specifically, the apparatus includes: a transceiver unit, configured to receive second indication information on a first primary channel, where the second indication information indicates that a type of NPCA of the first station is PPDU length-based NPCA; and a processing unit, configured to switch from the first primary channel to a second primary channel when a first PPDU is detected and the first PPDU meets a condition for triggering NPCA, where the second primary channel is a non-primary channel access NPCA primary channel, the first PPDU is a PPDU sent by a second station or a station associated with a second station, and a BSS to which the second station belongs and a BSS to which the first station belongs are OBSSs of each other. The processing unit is further configured to switch from the second primary channel to the first primary channel based on an end moment of the first PPDU.

[0093] According to a fourteenth aspect, a communication apparatus is provided. The apparatus may be a first AP or second station, or may be a component (for example, a chip, a circuit, or a chip system) of a first AP or a second station. The apparatus may have a function of implementing the fifth aspect. For example, the apparatus includes a corresponding module, unit, or means for performing the related operation in the fifth aspect. The module, unit, or means may be specifically implemented by software, or hardware, or a combination of software and hardware.

[0094] Specifically, the apparatus includes: a processing unit, configured to generate second indication information, where the second indication information indicates that a type of NPCA of the first station is PPDU length-based NPCA; and a transceiver unit, configured to send the second indication information on a first primary channel.

[0095] According to a fifteenth aspect, a communication apparatus is provided. The apparatus may be a first station, or may be a component (for example, a chip, a circuit, or a chip system) of a first station. The apparatus may have a function of implementing the sixth aspect. For example, the apparatus includes a corresponding module, unit, or means for performing the related operation in the sixth aspect. The module, unit, or means may be specifically implemented by software, or hardware, or a combination of software and hardware.

[0096] Specifically, the apparatus includes: a transceiver unit, configured to receive a first frame from a second station on a first primary channel, where the first frame includes an unavailability start moment, and a BSS to which the second station belongs and a BSS to which the first station belongs are OBSSs of each other; and a processing unit, configured to switch from the first primary channel to a second primary channel when a first PPDU is detected in a TXOP of the first frame and the first PPDU meets a condition for NPCA, where the second primary channel is an NPCA primary channel, and the first PPDU is a PPDU sent by the second station or a station associated with the second station. The processing unit is further configured to switch from the second primary channel to the first primary channel based on the unavailability start moment.

[0097] According to a sixteenth aspect, a communication apparatus is provided. The apparatus may be a first station, or may be a component (for example, a chip, a circuit, or a chip system) of a first station. The apparatus may have a function of implementing the seventh aspect. For example, the apparatus includes a corresponding module, unit, or means for performing the related operation in the seventh aspect. The module, unit, or means may be specifically implemented by software, or hardware, or a combination of software and hardware.

[0098] Specifically, the apparatus includes: a transceiver unit, configured to receive a first frame from a second station on a first primary channel, where the first frame is used to query unavailability information of a station associated with the second station, or the first frame is used to carry unavailability information of the second station; and a BSS to which the second station belongs and a BSS to which the first station belongs are OBSSs of each other; and a processing unit, configured to stay on the first primary channel before receiving an end indication of a TXOP of the first frame, or configured to stay on the first primary channel before countdown of an NAV timer set based on the first frame ends.

[0099] According to a seventeenth aspect, a communication apparatus is provided. The apparatus may be a first station, or may be a component (for example, a chip, a circuit, or a chip system) of a first station. The apparatus may have a function of implementing the eighth aspect. For example, the apparatus includes a corresponding module, unit, or means for performing the related operation in the eighth aspect. The module, unit, or means may be specifically implemented by software, or hardware, or a combination of software and hardware.

[0100] Specifically, the apparatus includes: a transceiver unit, configured to receive a second frame from a second station on a first primary channel, where the second frame is used to transmit control information in a first multi-AP coordination procedure, the first multi-AP coordination procedure is a Co-SR procedure or a Co-BF procedure, and the second station participates in the first multi-AP coordination procedure; and a processing unit, configured to switch from the first primary channel to a second primary channel when the first station does not participate in the first multi-AP coordination procedure and it is detected that a first PPDU meets a condition for triggering NPCA, where the second primary channel is an NPCA primary channel, the first PPDU is a downlink data PPDU in the first multi-AP coordination procedure, and a BSS to which the second station belongs and a BSS to which the first station belongs are OBSSs of each other; or a processing unit configured to stay on the first primary channel in a TXOP of the first multi-AP coordination procedure when the first station participates in the first multi-AP coordination procedure and the second frame or a first PPDU is detected.

[0101] With reference to the seventeenth aspect, in some implementations, the processing unit is further configured to: switch from the second primary channel to the first primary channel based on an end moment of the TXOP of the first multi-AP coordination procedure; or switch from the second primary channel to the first primary channel based on an end moment of the first PPDU.

[0102] With reference to the seventeenth aspect, in some implementations, the first station is a first AP. Before receiving the second frame, the transceiver unit is further configured to send second indication information on the first primary channel after determining that the first AP and a third AP have reached a Co-BF or Co-SR agreement, where the second indication information indicates that a type of NPCA of a non-AP STA associated with the first AP is PPDU length-based NPCA.

[0103] With reference to the seventeenth aspect, in some implementations, the first station is a first non-AP STA. Before receiving the second frame, the transceiver unit is further configured to receive second indication information from a first AP on the first primary channel, where the second indication information indicates that a type of NPCA of a non-AP STA associated with the first AP is PPDU length-based NPCA, and the non-AP STA associated with the first AP includes the first non-AP STA.

[0104] According to an eighteenth aspect, a communication apparatus is provided. The apparatus may be a first station, or may be a component (for example, a chip, a circuit, or a chip system) of a first station. The apparatus may have a function of implementing the ninth aspect. For example, the apparatus includes a corresponding module, unit, or means for performing the related operation in the ninth aspect. The module, unit, or means may be specifically implemented by software, or hardware, or a combination of software and hardware.

[0105] Specifically, the apparatus includes a processing unit, configured to switch from a first primary channel to a second primary channel when a first PPDU is detected on the first primary channel and the first PPDU meets a condition for triggering NPCA, where the second primary channel is an NPCA primary channel, the first PPDU is a PPDU sent by a second station or a station associated with a second station, and a BSS to which the second station belongs and a BSS to which the first station belongs are OBSSs of each other. The processing unit is further configured to switch from the second primary channel to the first primary channel based on an end moment of the first PPDU.

[0106] With reference to the eighteenth aspect, in some implementations, the first station is a first non-AP STA. The apparatus further includes a transceiver unit, configured to receive second indication information from a first AP on the first primary channel, where the second indication information indicates that a type of NPCA of a non-AP STA associated with the first AP is PPDU length-based NPCA, and the non-AP STA associated with the first AP includes the first non-AP STA.

[0107] With reference to the eighteenth aspect, in some implementations, the first station is a first AP. The apparatus further includes a transceiver unit, configured to send second indication information on the first primary channel when determining that the second station enables a DUO mode, where the second indication information indicates that a type of NPCA of a non-AP STA associated with the first AP is PPDU length-based NPCA.

[0108] With reference to the eighteenth aspect, in some implementations, the first station is a first AP. The apparatus further includes a transceiver unit, configured to send second indication information on the first primary channel after determining that the first AP and a third AP have reached a Co-BF or Co-SR agreement, where the second indication information indicates that a type of NPCA of a non-AP STA associated with the first AP is PPDU length-based NPCA.

[0109] It should be understood that, for details not described in the tenth aspect to the eighteenth aspect, refer to the first aspect to the ninth aspect. Details are not described herein again.

[0110] According to a nineteenth aspect, a communication apparatus is provided. The apparatus includes: a memory, configured to store a program; and at least one processor, configured to execute a computer program or instructions stored in the memory, to perform the method provided in any one of the foregoing aspects or the implementations of the foregoing aspects.

[0111] In an implementation, the apparatus is a first station or a second station.

[0112] In another implementation, the apparatus is a chip, a chip system, or a circuit used in a first station or a second station.

[0113] According to a twentieth aspect, a communication apparatus is provided. The apparatus includes at least one processor and a communication interface. The at least one processor is configured to obtain, through the communication interface, a computer program or instructions stored in a memory, to perform the method provided in any one of the foregoing aspects or the implementations of the foregoing aspects. The communication interface may be implemented by hardware or software.

[0114] In an implementation, the apparatus further includes the memory.

[0115] According to a twenty-first aspect, a processor is provided, and is configured to perform the method provided in any one of the foregoing aspects.

[0116] Unless otherwise specified, or if operations such as sending and obtaining / receiving related to the processor do not conflict with actual functions or internal logic of the operations in related descriptions, the operations may be understood as operations such as outputting, receiving, and inputting of the processor, or may be understood as sending and receiving operations performed by a radio frequency circuit and an antenna. This is not limited in this application.

[0117] According to a twenty-second aspect, a computer-readable storage medium is provided. The computer-readable medium stores program code to be executed by a device, and the program code is used to perform the method provided in any one of the foregoing aspects or the implementations of the foregoing aspects.

[0118] According to a twenty-third aspect, a computer program product including instructions is provided. When the computer program product runs on a computer, the computer is enabled to perform the method provided in any one of the foregoing aspects or the implementations of the foregoing aspects.

[0119] According to a twenty-fourth aspect, a chip is provided. The chip includes a processor and a communication interface. The processor reads, through the communication interface, instructions stored in a memory, to perform the method provided in any one of the foregoing aspects or the implementations of the foregoing aspects. The communication interface may be implemented by hardware or software.

[0120] Optionally, in an implementation, the chip further includes the memory. The memory stores a computer program or instructions. The processor is configured to execute the computer program or instructions stored in the memory. When the computer program or instructions are executed, the processor is configured to perform the method provided in any one of the foregoing aspects or the implementations of the foregoing aspects.

[0121] When the method provided in this application is performed by the chip, a number of chips that specifically implement the method in this application is not limited in this application. For example, the method may be performed by one chip, or may be performed by two or more chips. In addition, when there are two or more chips that implement the method in this application, a chip vendor is not limited. The chips may be from a same vendor or from different vendors.

[0122] According to a twenty-fifth aspect, a computer program is provided. When the computer program runs on a computer, the method provided in any one of the foregoing aspects or the implementations of the foregoing aspects is performed.

[0123] According to a twenty-sixth aspect, a communication system is provided, including the first station and the second station.

[0124] It should be understood that, for beneficial effect of any one of the tenth aspect to the twenty-sixth aspect and the implementations of the tenth aspect to the twenty-sixth aspect, refer to any one of the first aspect to the ninth aspect and the implementations of the first aspect to the ninth aspect. BRIEF DESCRIPTION OF DRAWINGS

[0125] FIG. 1 is a diagram of a network architecture to which embodiments of this application are applicable;

[0126] FIG. 2 is a diagram of an NPCA procedure;

[0127] FIG. 3 is a schematic flowchart of a Co-BF transmission phase;

[0128] FIG. 4 is a diagram of a Co-BF sounding procedure;

[0129] FIG. 5 is a schematic flowchart of a Co-SR transmission phase;

[0130] FIG. 6 is a diagram of shortening a TXOP due to unavailability information;

[0131] FIG. 7 is a schematic flowchart of a communication method 700 according to this application;

[0132] FIG. 8 is a diagram of an NPCA trigger mechanism according to this application;

[0133] FIG. 9 is a diagram of a common information field and a special user information field according to an embodiment of this application;

[0134] FIG. 10 is a schematic flowchart of a communication method 1000 according to this application;

[0135] FIG. 11 is another diagram of an NPCA trigger mechanism according to this application;

[0136] FIG. 12 is another diagram of an NPCA trigger mechanism according to this application; and

[0137] FIG. 13 and FIG. 14 are diagrams of communication apparatuses according to this application. DESCRIPTION OF EMBODIMENTS

[0138] The following describes technical solutions of this application with reference to accompanying drawings.

[0139] Embodiments of this application may be applied to a WLAN, for example, support the Institute of Electrical and Electronics Engineers (institute of electrical and electronics engineers, IEEE) 802.11 related standards (or referred to as protocols), for example, the 802.11a / b / g standard, the 802.11n standard, the 802.11ac standard, the 802.11ax standard (namely, Wi-Fi 6, also referred to as a high efficiency (high efficiency, HE) standard), the 802.11be standard (namely, Wi-Fi 7, also referred to as an extremely high throughput (extremely high throughput, EHT)) standard, the 802.11bn standard (namely, Wi-Fi 8, also referred to as an ultra high reliability (ultra high reliability, UHR) standard), or a next-generation standard of Wi-Fi 8; and 802.11ad, 802.11ay, and the like are further included. Embodiments of this application may be further applied to a wireless local area network system that supports an integrated millimeter wave (integrated millimeter wave, IMMW), may be further applied to a wireless local area network system that supports an ultra-wideband (ultra wide band, UWB), for example, 802.15 series standards, may be further applied to a sensing (sensing) system, for example, 802.11bf series standards, or may be applied to wireless positioning, for example, 802.11az. This application may also support standards such as SparkLink (spark link) and Nearlink (nearlink).

[0140] It should be understood that, in this application, a standard and a protocol may be replaced with each other. Unless otherwise specified, the IEEE 802.11 standard is referred to as the 802.11 standard for short.

[0141] The technical solutions in embodiments of this application may be further applied to various communication systems, for example, a 5th generation (5th generation, 5G) system or new radio (new radio, NR), a future communication system, an internet of things (internet of things, IoT), or a vehicle to everything (vehicle to x, V2X) network.

[0142] The foregoing communication systems to which this application is applicable are merely examples for description, and the communication systems to which this application is applicable are not limited thereto. This is uniformly described herein, and details are not described below again.

[0143] The WLAN may include a plurality of basic service sets (basic service set, BSS), and network nodes in the BSS are collectively referred to as stations (station, STA). The BSS is a basic module of an IEEE 802.11 local area network. Based on different topology structures, functions, and the like, the BSS may be classified into an infrastructure BSS (infrastructure BSS), an independent BSS (independent BSS), and the like.

[0144] From a perspective of a topology structure of a station, a station in the infrastructure BSS is configured to access a distribution system (distribution system, DS), and the station is referred to as an AP station, which is referred to as an AP for short. Another station is referred to as a non-access point station, which is referred to as a non-AP station (non-AP STA) for short, and the non-AP STA can access the DS only through the AP. Therefore, STAs in the infrastructure BSS may be specifically classified into an AP and a non-AP STA, and each BSS may include one AP and a plurality of non-AP STAs associated with the AP. In a BSS, data may be transmitted between an AP and each non-AP STA. A BSS may also be understood as a cell. STAs in the independent BSS are equal, and there is no distinction between an AP and a non-AP STA. Data may be transmitted between the STAs. Unless otherwise specified in this application, the BSS is an infrastructure BSS, and the station may be an AP or a non-AP STA.

[0145] An AP in embodiments of this application may also be referred to as a wireless access point, a hotspot, or the like. The AP is an access point for a mobile user to access a wired network, and is mainly deployed at home, in a building, and in a campus, with a typical coverage radius of tens of meters to hundreds of meters. Certainly, the AP may alternatively be deployed outdoors. The AP is equivalent to a bridge that connects a wired network and a wireless network. The AP is mainly used to connect wireless network clients together and then connect the wireless network to an ethernet. Specifically, the AP may be a device that supports 802.11 series standards. For example, the AP may be a device that supports one or more WLAN standards such as 802.11ac, 802.11ax, 802.11be, 802.11bn, or a later version.

[0146] A non-AP STA in embodiments of this application may be a wireless communication chip, a wireless sensor, or a wireless communication terminal, for example, a mobile phone supporting a Wi-Fi communication function, a tablet computer supporting a Wi-Fi communication function, a set-top box supporting a Wi-Fi communication function, a smart television supporting a Wi-Fi communication function, an intelligent wearable device supporting a Wi-Fi communication function, a vehicle-mounted communication device supporting a Wi-Fi communication function, and a computer supporting a Wi-Fi communication function. The nonAP STA may be a device that supports 802.11 series standards. For example, the non-AP STA may be a device that supports one or more WLAN standards such as 802.11ac, 802.11ax, 802.11be, 802.11bn, or a later version.

[0147] In embodiments of this application, the non-AP STA or the AP includes a hardware layer, an operating system layer running above the hardware layer, and an application layer running above the operating system layer. The hardware layer includes hardware such as a central processing unit (central processing unit, CPU), a memory management unit (memory management unit, MMU), and a memory (also referred to as a main memory). An operating system may be any one or more computer operating systems that implement service processing through a process (process), for example, a Linux operating system, a Unix operating system, an Android operating system, an iOS operating system, or a Windows operating system. The application layer includes applications such as a browser, an address book, word processing software, and instant messaging software. In addition, a specific structure of an execution body of a method provided in embodiments of this application is not specifically limited in embodiments of this application, provided that a program that records code of the method provided in embodiments of this application can be run to perform communication according to the method provided in embodiments of this application. For example, the execution body of the method provided in embodiments of this application may be the non-AP STA or the AP, or may be a functional module that is in the non-AP STA or the AP and that can invoke and execute the program.

[0148] In addition, aspects or features of this application may be implemented as a method, an apparatus, or a product that uses standard programming and / or engineering technologies. The term "product" used in this application covers a computer program that can be accessed from any computer-readable component, carrier or medium. For example, a computer-readable medium may include but is not limited to: a magnetic storage component (for example, a hard disk, a floppy disk or a magnetic tape), an optical disc (for example, a compact disc (compact disc, CD), a digital versatile disc (digital versatile disc, DVD)), a smart card and a flash memory component (for example, an erasable programmable read-only memory (erasable programmable read-only memory, EPROM), a card, a stick, or a key drive). In addition, various storage media described in this specification may represent one or more devices and / or other machine-readable media that are configured to store information. The term "machine-readable media" may include but is not limited to a radio channel, and various other media that can store, contain and / or carry instructions and / or data.

[0149] FIG. 1 is a diagram of a network architecture of a wireless local area network to which an embodiment of this application is applicable. FIG. 1 includes (a) of FIG. 1 and (b) of FIG. 1.

[0150] As shown in (a) of FIG. 1, one BSS may include one AP and one or more non-AP STAs associated with the AP. The network architecture of the wireless local area network may further include a plurality of BSSs. For example, as shown in (b) of FIG. 1, a BSS #1, a BSS #2, and a BSS #3 are three infrastructure BSSs that access a DS. The AP #1, the AP #2, and the AP #3 are configured to access the DS, and the AP #1, the AP #2, and the AP #3 may also communicate with each other. A non-AP STA 11, a non-AP STA 12, and a non-AP STA 13 in the BSS #1 access the DS via the AP #1, a non-AP STA 21, a non-AP STA 22, and a non-AP STA 23 in the BSS #2 access the DS via the AP #2, and a non-AP STA 31 and a non-AP STA 32 in the BSS #3 access the DS via the AP #3. The BSS #1 and the BSS #2 partially overlap with each other, that is, the two BSSs are overlapping basic service sets (overlapped basic service set, OBSS) of each other, and the nonAP STA 11, the non-AP STA 12, and the non-AP STA 23 are mutually overlapping parts of the two BSSs. The BSS #3 does not overlap with the BSS #1, and the BSS #3 does not overlap with the BSS #2. Non-AP STAs may communicate with each other through an AP.

[0151] In this application, an OBSS is a BSS that has overlapping coverage and that uses an overlapping channel. Specifically, to reduce signal coverage blind spots, coverage of APs may overlap with each other during AP deployment. However, a spectrum is limited, and a same channel is repeatedly used by a plurality of BSSs. In this way, BSSs whose coverage overlap with each other may use overlapping channels. Therefore, OBSSs may communicate with each other, but also interfere with each other. An OBSS station is a station in a BSS that is an OBSS of a BSS to which a local station belongs. For example, in (b) of FIG. 1, the BSS #1 and the BSS #2 are OBSSs of each other. Therefore, for any one of the AP #1, the non-AP STA 11, the non-AP STA 12, and the non-AP STA 13, any one of the AP #2, the non-AP STA 21, the non-AP STA 22, and the non-AP STA 23 is an OBSS station; and for any one of the AP #2, the non-AP STA 21, the non-AP STA 22, and the non-AP STA 23, any one of the AP #1, the non-AP STA 11, the non-AP STA 12, and the non-AP STA 13 is an OBSS station.

[0152] It should be understood that FIG. 1 is merely an example, and should not limit the network architecture of the wireless local area network to which this application is applicable. For example, the network architecture may further include more BSSs, each BSS may further include more non-AP STAs, or some BSSs may not include an AP. An overlapping area of a plurality of BSSs may further include more non-AP STAs and the like. This is not limited in embodiments of this application.

[0153] For ease of understanding this application, some terms that may be used in this application are first briefly described.

[0154] 1. NPCA

[0155] In an 802.11 protocol, an AP may operate on frequency bands such as 2.4 GHz, 5 GHz, and 6 GHz. The AP occupies a specific channel (channel) on a frequency band, for example, an 80 MHz channel in 5 GHz, and communicates with a non-AP STA on these channels. With development of the 802.11 protocol, a bandwidth of a channel that can be occupied by an AP is increasingly large. In 802.11be, a maximum bandwidth of a channel available to the AP may reach 320 MHz. These large-bandwidth channels are logically divided into 20 MHz sub-channels. For example, an 80 MHz channel may be divided into four 20 MHz sub-channels. A 20 MHz subchannel in a BSS is classified into a primary channel (Primary channel) and a non-primary channel (non-primary channel). Which sub-channel is specifically selected as a primary channel is determined based on a configuration of the BSS. A non-primary channel in an operating bandwidth (operating bandwidth) of the AP may also be referred to as a secondary channel (secondary channel), a subordinate channel, or the like. The "bandwidth of a channel that can be occupied by an AP" may be understood as a bandwidth that can be supported by the AP or a bandwidth that can be theoretically occupied by the AP. The "operating bandwidth of the AP" may be understood as an operating bandwidth of the AP, a bandwidth for actual communication of the AP, or a bandwidth actually occupied by the AP. The operating bandwidth of the AP is a part or all of the bandwidth of the channel that can be occupied by the AP.

[0156] Unless otherwise specified in this application, the primary channel mentioned herein is a primary 20 MHz sub-channel, and the non-primary channel is a 20 MHz sub-channel other than the primary 20 MHz sub-channel. It should be understood that, in addition to the primary 20 MHz sub-channel, there is also a primary 40 MHz channel, a primary 80 MHz channel, and the like, each of which includes a primary 20 MHz sub-channel. Correspondingly, a secondary 40 MHz channel, a secondary 80 MHz channel, or the like indicates a part that does not include the primary 20 MHz sub-channel.

[0157] When the AP communicates with a non-AP STA, to avoid a collision, the station (for example, the AP or the non-AP STA) needs to perform carrier sense (carrier sense) to ensure that a channel is idle. Specifically, the station may perform energy detection (ED, energy detection) on all sub-channels, and perform preamble detection (PD, preamble detection) on a primary channel. In ED, strength of a wireless signal on the sub-channel is detected. If there is a strong wireless signal, the sub-channel is determined to be in a busy (busy) state. In PD, whether there is a PPDU on the primary channel is detected, and the detected PPDU is decoded to extract related information. The information extracted from the PPDU may include a duration (Duration) field, which indicates how long it takes to complete frame exchange after the PPDU. The station may set a corresponding NAV timer (NAV timer) based on the duration field obtained through decoding in PD on the primary channel. An end moment of the NAV timer is an end time indicated by the duration field. Before the NAV timer ends, the station cannot contend for a channel, thereby protecting a TXOP of another station (for example, a station that sends the PPDU). Due to high complexity of PD, the protocol requires that PD is performed on only the primary channel, that is, "primary channel access (primary channel access)". ED and the PD may be collectively referred to as clear channel assessment (clear channel assessment, CCA).

[0158] A primary channel access mechanism is simple to implement, and has been able to meet requirements of most scenarios for a long period of time. However, with development of the 802.11 protocol, an available bandwidth of a station is increasingly large. When the primary channel is busy and a non-primary channel is idle, primary channel access determines that an entire channel is unavailable, resulting in a waste of resources of the non-primary channel. Although operating bandwidths (operating bandwidth) of the station are increased, these bandwidths cannot be well used.

[0159] Therefore, a "non-primary channel access" mechanism is proposed in 802.11bn. Specifically, when the primary channel is busy, the station may switch to a sub-channel of a nonprimary channel to perform PD, thereby improving channel utilization. For example, an operating bandwidth of an AP is 160 MHz, and an 80 MHz PPDU is detected through PD on a primary channel. In this case, the AP may switch to a 20 MHz sub-channel of an idle secondary 80 MHz channel to perform PD. A sub-channel that is of a non-primary channel and that is used for PD is referred to as an NPCA primary channel (NPCA primary channel), and may also be referred to as a temporary primary channel or an NPCA anchor channel (anchor channel). Generally, NPCA is applied on a per BSS basis. If an AP and a non-AP STA in a BSS (for example, a BSS 1) detect transmission of an OBSS on a primary channel, for example, a TXOP of a BSS 2, both the AP and the non-AP STA in the BSS 1 switch to an NPCA primary channel for communication. It should be noted that, if transmission of the BSS, for example, a TXOP of the BSS 1, is detected, it indicates that the AP in the BSS is performing communication. Therefore, the station does not perform NPCA switching.

[0160] FIG. 2 is a diagram of NPCA. An operating bandwidth of an AP 1 is 160 MHz, and includes a primary 80 MHz channel (namely, "P80" in FIG. 2) and a secondary 80 MHz channel (namely, "S80" in FIG. 2); and an NPCA primary channel is set on a sub-channel of the secondary 80 MHz channel (indicated by "NPCA P20" in FIG. 2). When the AP 1 performs PD on a primary channel (indicated by "P20" in FIG. 2) and finds that the channel is occupied by an OBSS, the AP 1 does not need to perform backoff on the primary channel, but switches to the NPCA primary channel to perform PD for channel contention, so that transmission can be performed on a channel that is not occupied by the OBSS.

[0161] 2. TXOP

[0162] The TXOP is a period of time (or referred to as a time period) in which a station may initiate a frame exchange sequence, and may be defined based on a start moment and maximum duration. When a channel is idle, the station may obtain a TXOP through contention, and the station may perform transmission in the TXOP. In addition, a plurality of PPDUs may be transmitted in one TXOP. The station that obtains the TXOP is referred to as a TXOP holder (TXOP holder), and a peer station that performs transmission with the station in the TXOP is referred to as a TXOP responder (TXOP responder). A length of the TXOP is a length of a 1st PPDU in the TXOP plus a length indicated by a duration field in the 1st PPDU in the TXOP. Another station does not perform channel contention before an end moment of the PPDU and before an NAV timer ends, so that the TXOP of the station can be protected. If the TXOP of the station ends in advance, even if the channel is idle, another station still needs to wait until countdown of the original NAV timer ends before starting to contend for the channel. To enable another station to contend for the channel in time, the station may reset an NAV timer of the another station to 0 in some manners after the TXOP ends in advance. For example, a manner of indicating reset of an NAV of the another station may be that the station sends a contention free end (contention free end, CF-End) frame.

[0163] It should be understood that both the length of the PPDU and the length of the TXOP mentioned above are time lengths, namely, duration.

[0164] 3. In-device coexistence (in-device coexistence, IDC) and unavailability information (unavailability information)

[0165] In the 802.11 protocol, interference caused by coexistence of a plurality of wireless technologies in a station (including an AP or a non-AP STA) is considered in IDC. Specifically, because the IEEE 802.11 protocol (or referred to as Wi-Fi) and another wireless technology (for example, Bluetooth) may use overlapping channels, different technologies interfere with each other during transmission. For example, Bluetooth may interfere with Wi-Fi, and consequently cannot normally perform transmission. To avoid interference caused by transmission of another wireless technology and to reduce interference caused by transmission performed by using the 802.11 protocol to transmission of the another wireless technology, the station needs to perform backoff during transmission of the another wireless technology (that is, during IDC). As a result, the station is in an unavailability (unavailability) state during this period, and cannot normally perform transmission by using the 802.11 protocol. In other words, the station has unavailability information due to IDC.

[0166] For example, the AP or the non-AP STA is completely unavailable or partially unavailable during IDC, depending on a channel occupied by the another wireless technology. Optionally, unavailability (unavailability) caused by IDC may be reflected in a plurality of aspects, for example, a device cannot perform transmission in a specific time period, or an available bandwidth (bandwidth) is reduced, or a number of available spatial streams (NSS, number of spatial streams) is reduced.

[0167] IDC can be classified into periodic IDC and aperiodic IDC. Generally, periodic IDC occurs periodically, lasts for a specific time period, and is easy to predict in advance; and aperiodic IDC is mostly burst IDC, has an uncertain start moment and uncertain duration, and is difficult to predict in advance. In addition, IDC may be further classified into long-term IDC and short-term IDC. Periodic IDC is generally long-term IDC, and aperiodic IDC is generally short-term IDC. Because IDC causes device unavailability, the station may notify, in advance, a peer station of the unavailability information caused by IDC, to avoid invalid transmission and a resource waste.

[0168] When the unavailability information is notified, different methods may be used in consideration of a difference between periodic IDC and aperiodic IDC. An operation mode that supports the AP or the non-AP STA to notify periodic unavailability information may be referred to as a periodic unavailability operation (periodic unavailability operation, PUO) mode. An operation mode that supports the AP or the non-AP STA to notify aperiodic or dynamic unavailability information may be referred to as a DUO mode. The PUO mode may also be referred to as a PUO mechanism, and the DUO mode may also be referred to as a DUO mechanism.

[0169] For example, IDC mainly occurs on a non-AP STA side because the non-AP STA usually supports a plurality of wireless technologies, but may also occur on an AP side, especially a mobile AP (mobile AP).

[0170] It should be noted that IDC may also be referred to as coexistence (coexistence, CoEx) or another name. This is not limited in this application. For ease of description, IDC is used as an example for description in this specification. In addition, the foregoing unavailability information caused by IDC may also be referred to as IDC information, PUO information, DUO information, or the like.

[0171] 4. Co-BF

[0172] In the IEEE 802.11bn protocol, to further improve transmission efficiency of an air interface, a multi-AP coordination (Multi-AP Coordination, MAPC) framework is proposed. In the multi-AP coordination framework, APs may perform transmission via air interface resources more efficiently based on various coordination mechanisms.

[0173] Co-BF is one of multi-AP coordination mechanisms. A plurality of APs that have a plurality of antennas and that participate in Co-BF adjust a signal transmission direction based on channel state information (channel state information, CSI), to obtain better throughput and reliability and reduce a delay. Specifically, two APs (an AP 1 and an AP 2) participating in Co-BF may implement simultaneous transmission with respective associated non-AP STAs based on CSI between a local AP and a non-AP STA of the other AP (for example, the AP 1 and a non-AP STA 2, where the non-AP STA 2 is associated with the AP 2), and minimize interference to an OBSS station.

[0174] To obtain CSI between an AP and a non-AP STA, a Co-BF sounding (sounding) procedure needs to be performed before data transmission. A phase in which an AP participating in Co-BF obtains CSI through sounding may be referred to as a Co-BF sounding phase, and a phase in which data transmission (transmission) is performed through Co-BF may be referred to as a Co-BF transmission phase.

[0175] In IEEE 802.11bn, two APs participating in Co-BF transmission is limited. During Co-BF transmission, one AP obtains a TXOP and initiates Co-BF transmission to the other AP. In this case, the AP that initiates Co-BF transmission may be referred to as a sharing (sharing) AP, and the other AP may be referred to as a shared (shared) AP. In this application, an example in which there is one shared AP is used for description. However, a number of shared APs is not limited in this application. In addition, in this application, the sharing AP may also be referred to as a sharing AP, a primary AP, an initiating (initiating) AP, a coordinating (coordinating) AP, an inviting (inviting) AP, or the like. Similarly, the shared AP may also be referred to as a shared AP, a secondary AP, a responding (responding) AP, a coordinated (coordinated) AP, an invited (invited) AP, or the like.

[0176] FIG. 3 is a schematic flowchart of a Co-BF transmission phase. As shown in FIG. 3, the AP 1 is a sharing AP, the AP 2 is a shared AP, a BSS to which the AP 1 belongs and a BSS to which the AP 2 belongs are OBSSs of each other, and the two APs may simultaneously transmit downlink data PPDUs without interfering with each other. Specifically, after obtaining a TXOP, the AP 1 initiates Co-BF transmission to the AP 2 by sending a Co-BF invite (Co-BF invite) frame; and the AP 2 indicates, by replying with a Co-BF response (Co-BF response) frame, to participate in Co-BF transmission, and includes parameter information required for the Co-BF transmission. After the Co-BF invite frame and the Co-BF response frame are exchanged, if necessary, the two APs sequentially exchange an ICF and an ICR frame with respective non-AP STAs. Functions of the ICF and the ICR frame include: enabling an enhanced multi-link single-radio (EMLSR, enhanced multi-link single-radio) STA to switch from a listening state to a state in which frame exchange can be performed, enabling a dynamic power save (DPS, dynamic power save) STA to switch from a low-capability mode to a high-capability mode, and the like. In FIG. 3, an ICF 1 and an ICR 1 represent an ICF and an ICR between the sharing AP and a non-AP STA 1, and an ICF 2 and an ICR 2 represent an ICF and an ICR between the shared AP and a non-AP STA 2. Then, the sharing AP sends a Co-BF trigger (Co-BF trigger) frame, to trigger Co-BF transmission of a downlink (downlink, DL) PPDU (namely, a Co-BF data PPDU or a data PPDU for short). Data PPDUs transmitted by different APs need to be aligned (that is, the data PPDUs start at the same time and end at the same time), preambles of data PPDUs sent by the AP 1 and the AP 2 are the same, and a U-SIG field in each preamble includes BSS colors of the two APs. After receiving the data PPDUs from the respective APs, the non-AP STAs associated with the two APs reply with block acknowledgment (block acknowledgment, BA) frames to acknowledge that the data PPDUs have been received. In FIG. 3, for example, the two non-AP STAs simultaneously reply the associated APs with BA. Alternatively, the two non-AP STAs may reply with BA in sequence.

[0177] It should be understood that there may be another form of frame exchange procedure in the Co-BF transmission phase, but the procedure is basically similar to that in FIG. 3, and includes frame exchange between the two APs, ICF or ICR frame exchange between each AP and a non-AP STA associated with the AP, aligned DL PPDU transmission, and replying the associated AP with BA from the non-AP STA. A frame exchange procedure in the Co-BF transmission phase is not limited in this application.

[0178] In addition, in this application, the ICR frame may be referred to as an ICR for short. Unless otherwise specified, the ICR represents the ICR frame.

[0179] FIG. 4 is a diagram of a Co-BF sounding procedure. As shown in FIG. 4, there are two Co-BF sounding procedures: sequential sounding (sequential sounding) as shown in (a) of FIG. 4, and joint sounding (joint sounding) as shown in (b) of FIG. 4. Through sounding, the AP 1 may obtain CSI between the AP 1 and the non-AP STA 1 and CSI between the AP 1 and the non-AP STA 2, and the AP 2 may obtain CSI between the AP 2 and the non-AP STA 2 and CSI between the AP 2 and the non-AP STA 1. The two sounding procedures are generally similar. A main difference lies in that, when each non-AP STA performs sounding, in sequential sounding, the AP 1 and the AP 2 sequentially send null data PPDU (null data PPDU, NDP) frames, and in joint sounding, the two APs simultaneously send NDPs. In the two sounding procedures, there is sounding invite (sounding invite) frame and sounding response (sounding response) frame exchange between the AP 1 and the AP 2, and ICF and ICR frame exchange between each AP and a respective non-AP STA. Functions of an ICF and an ICR frame are similar to those of corresponding frames in the Co-BF transmission procedure. In FIG. 4, an NDPA is a null data PPDU announcement (null data PPDU announcement) frame, and a BFRP is a beamforming report poll (beamforming report poll) frame. In FIG. 4, CSI may represent a frame carrying CSI information, for example, an EHT compressed beamforming / channel quality indication (compressed beamforming / channel quality indication, compressed beamforming / CQI) frame or a UHR compressed beamforming / channel quality indication frame.

[0180] 5. Co-SR

[0181] Co-SR is another multi-AP coordination mechanism introduced in IEEE 802.11bn. A plurality of APs participating in Co-SR perform transmit power control (transmit power control) in a coordinated manner, thereby reducing interference to an OBSS station, and effectively performing parallel transmission with respective non-AP STAs via an air interface. In other words, the AP performs transmission in a manner of limiting transmit power, so that strength of signals received by another AP and a non-AP STA associated with the another AP falls within a range in which no interference is generated. The APs may notify each other of related information of transmit power control in a coordinated manner.

[0182] There may be two or more APs participating in Co-SR transmission. In this application, two APs are used as an example for description. Similar to Co-BF, during Co-SR transmission, one AP obtains a TXOP and initiates Co-SR transmission to another AP. In this case, the AP that initiates Co-SR transmission may be referred to as a sharing AP, and the another AP is referred to as a shared AP.

[0183] FIG. 5 is a schematic flowchart of a Co-SR transmission phase. In FIG. 5, an AP 1 is a sharing AP, an AP 2 is a shared AP, a BSS to which the AP 1 belongs and a BSS to which the AP 2 belongs are OBSSs of each other, and the two APs may simultaneously transmit downlink data PPDUs without interfering with each other. A frame exchange procedure of Co-SR transmission is similar to a Co-BF transmission procedure, and a function of each frame is not described herein again. A main difference between Co-SR and Co-BF lies in different DL PPDU transmission manners.

[0184] It can be learned from the foregoing description that there are a plurality of different mechanisms in a WLAN protocol. When an NPCA mechanism and another mechanism (for example, a DUO mechanism or a multi-AP coordination mechanism) coexist, problems such as a resource waste and a transmission failure may be caused.

[0185] For example, when the NPCA mechanism and the DUO mechanism coexist, if a station is triggered for NPCA by a frame that is sent by the OBSS station and that is used to query or notify unavailability information, channel utilization efficiency of the station may be reduced. The unavailability information may be understood as unavailability information in the DUO mechanism, namely, DUO information.

[0186] Specifically, after the OBSS station (for example, a non-AP STA 2) enables a DUO mode, an AP (for example, the AP 2) associated with the OBSS station needs to send an ICF for querying unavailability information, before initiating data transmission to the OBSS station. After receiving the ICF, the non-AP STA 2 replies with an ICR, and indicates the unavailability information in the ICR, for example, unavailability target start time (unavailability target start time, which may also be referred to as unavailability start moment) and unavailability duration (unavailability duration). The ICF sent by the AP 2 is used as a start of frame exchange, and the ICF is used to query unavailability information of a non-AP STA. In this case, the ICF is a BSRP frame. After receiving the ICF sent by the AP 2, the non-AP STA 2 needs to reply with the ICR, and includes the unavailability information in the ICR. In this case, the ICR may be a multi-STA BA frame. In addition, if the non-AP STA is a TXOP holder, the non-AP STA may also actively send an ICF to the AP, and include the unavailability information of the non-AP STA in the ICF. In this case, the ICF may be a BSRP frame.

[0187] After the AP 2 learns of the unavailability information of the non-AP STA 2 as a TXOP holder, if the non-AP STA 2 is unavailable in this TXOP period, to avoid a transmission failure between the AP 2 and the non-AP STA 2, the AP 2 may choose to shorten the TXOP in this case, perform transmission with the non-AP STA 2 only before the unavailability start moment of the non-AP STA 2, and send a CF-End to end the TXOP in advance after transmission is completed; or the AP 2 may directly terminate the TXOP after ICF and ICR exchange. Because the AP 2 operates on a primary channel (for example, a primary 20 MHz channel, denoted as P20), for a station in the BSS (for example, the AP 1 or a non-AP STA 1), an ICF or ICR on the primary channel triggers the AP 1 or the non-AP STA 1 to perform NPCA. According to a current NPCA rule, both the AP 1 and the non-AP STA 1 switch to an NPCA primary channel (for example, an NPCA primary 20 MHz channel, denoted as NPCA P20) after the ICR, and switch from the NPCA primary channel back to the primary channel before an end moment of an initial TXOP (namely, the TXOP before shortening or an unterminated TXOP) of the AP 2. However, because the AP 2 shortens or terminates the TXOP in advance, the primary channel is in an idle state before the end moment of the initial TXOP. In addition, the AP 1 and the non-AP STA 1 do not participate in contention for the primary channel in this period of time, wasting resources of the primary channel. The following provides descriptions with reference to FIG. 6.

[0188] (a) of FIG. 6 is a diagram of shortening the TXOP due to a DUO. As shown in the figure, the AP 2 and the non-AP STA 1 communicate on the primary channel. After learning of the unavailability information of the non-AP STA 2 from the ICR, the AP 2 ends transmission with the non-AP STA 2 before the unavailability start moment, and sends the CF-End to end the TXOP in advance. The AP 1 and the non-AP STA 1 are not triggered for NPCA based on the ICF or the ICR, for example, switch to the NPCA primary channel after detecting a downlink PPDU of the AP 2 (for example, at a moment #1), and switch back to the primary channel at an end moment (for example, at a moment #3) of the initial TXOP of the AP 2. However, the AP 2 has ended the TXOP at a moment #2. No signaling is transmitted on the primary channel between the moment 2 and the moment 3, wasting resources of the primary channel. In the accompanying drawings of this application, P20 represents a primary channel, and NPCA P20 represents an NPCA primary channel. An unavailability time period is a period of time determined based on the unavailability start moment and the unavailability duration.

[0189] (b) of FIG. 6 is a diagram of directly terminating the TXOP after the ICR due to a DUO. As shown in the figure, after learning of the unavailability information of the non-AP STA 2 from the ICR, the AP 2 directly terminates the TXOP because there is no sufficient time for data transmission. The AP 1 and the non-AP STA 1 are triggered for NPCA based on the ICF or the ICR, for example, switch to the NPCA primary channel after the ICR (for example, at a moment #1), and switch back to the primary channel at an end moment (for example, at a moment #3) of the initial TXOP of the AP 2. However, the AP 2 has ended the TXOP at a moment #2'. No signaling is transmitted on the primary channel between the moment # 2' and the moment # 3, wasting resources of the primary channel.

[0190] In addition, in the foregoing process, after the TXOP of the AP 2 ends in advance, another station may obtain a channel through contention and set a new NAV, but the AP 1 and the non-AP STA 1 do not have latest NAV information after switching back to the primary channel at the moment #3. As a result, the AP 1 and the non-AP STA 1 may incorrectly determine a channel status in a medium synchronization (medium sync) loss state, and interfere with transmission of another station.

[0191] It should be understood that, in the current NPCA rule, NPCA may be triggered by control frame exchange of an OBSS, or an HE PPDU, an EHT PPDU, or a UHR PPDU of the OBSS; and switching back to the primary channel is performed based on the end time of the OBSS TXOP.

[0192] For another example, when the NPCA mechanism and the Co-BF mechanism coexist, a non-AP STA associated with a Co-BF AP is triggered for NPCA by a Co-BF ICF or ICR. As a result, the non-AP STA cannot reply the AP associated with the non-AP STA with the ICR, and cannot participate in the sounding and transmission procedures.

[0193] Specifically, the frame exchange procedure in the Co-BF transmission phase in FIG. 3 is used as an example. Frame exchange in the Co-BF transmission phase is performed on the primary channel. However, due to the NPCA mechanism, the ICF 1 and the ICR 1 are OBSS control frames for the non-AP STA 2, and may trigger NPCA of the non-AP STA 2. If the non-AP STA 2 is triggered for NPCA by the ICF 1 or the ICR 1, for example, the non-AP STA 2 switches to the NPCA primary channel at the moment #1, the non-AP STA 2 switches to the NPCA primary channel until the entire TXOP ends. As a result, the non-AP STA 2 cannot reply with the ICR 2 on the primary channel, and cannot receive a DL PPDU from the AP 2, resulting in a transmission failure, and wasting transmission resources.

[0194] Similarly, in the Co-BF sounding phase and the Co-SR transmission phase, ICF or ICR exchange between the AP 1 and the non-AP STA 1 also triggers the non-AP STA 2 to perform NPCA. As a result, the non-AP STA 2 cannot participate in Co-BF sounding or Co-SR transmission, wasting transmission resources.

[0195] In view of this, this application provides a communication method and a communication apparatus, to improve resource utilization when the NPCA mechanism and the DUO mechanism coexist or when the NPCA mechanism and the multi-AP coordination mechanism coexist.

[0196] It should be understood that in the following embodiments, the method is illustrated by using an example in which a first station, a second station, and the like are used as execution bodies. However, the execution body is not limited in this application, provided that communication can be performed according to the method provided in embodiments of this application by running a program that records code of the method provided in embodiments of this application. The method provided in embodiments of this application may be performed by the first station, the second station, or the like, or may be performed by a functional module, that can invoke a program and execute the program, in the first station, the second station, or the like. This is not limited.

[0197] FIG. 7 is a schematic flowchart of a communication method 700 according to this application. The method may be used to resolve a problem that occurs when an NPCA mechanism and a DUO mechanism coexist. As shown in FIG. 7, the method 700 includes the following steps.

[0198] S710: A second station sends a first frame to a first station on a first primary channel, and correspondingly, the first station receives the first frame on the first primary channel, where the first frame is used to query unavailability information of a station associated with the second station, or the first frame is used to carry unavailability information of the second station.

[0199] The first frame is a frame exchanged between the second station and the station associated with the second station. A BSS to which the second station belongs and a BSS to which the first station belongs are OBSSs of each other. In other words, the second station is an OBSS station of the first station. Therefore, the first station can receive the first frame, and obtain a part or all of information in the first frame through parsing.

[0200] In an example, the second station may be a second AP. The second AP sends the first frame to query unavailability information of a second non-AP STA, and the second non-AP STA is associated with the second AP.

[0201] Specifically, after the second non-AP STA enables a DUO mode, the second AP queries the unavailability information of the second non-AP STA via the first frame; and after receiving the first frame, the second non-AP STA may feed back the unavailability information of the second non-AP STA to the second AP.

[0202] In another example, the second station may be a second non-AP STA. The second nonAP STA sends the first frame to carry unavailability information of the second non-AP STA.

[0203] Specifically, after the second non-AP STA enables a DUO mode, a second AP queries the unavailability information of the second non-AP STA; and the second non-AP STA may feed back the unavailability information of the second non-AP STA to the second AP via the first frame.

[0204] The first station may be referred to as an NPCA station; and is a first AP, or may be a first non-AP STA. The first non-AP STA is associated with the first AP. The BSS to which the first non-AP STA and the first AP belong may be denoted as a first BSS, and a BSS to which the second non-AP STA and the second AP belong may be denoted as a second BSS. The first BSS and the second BSS are OBSSs of each other.

[0205] For example, the unavailability information may be information about time in which the second station cannot use a WLAN technology for communication. For example, the unavailability information may include one or more of an unavailability start moment, an unavailability end moment, unavailability duration, and the like. Specifically, the unavailability information in this application may be unavailability information in the DUO mechanism, namely, DUO information.

[0206] For example, the first primary channel is a primary 20 MHz channel.

[0207] S720: The first station switches from the first primary channel to a second primary channel when the first station detects a first PPDU in a TXOP of the first frame and the first PPDU meets a condition for triggering NPCA.

[0208] The TXOP of the first frame may be set by the second station via the first frame. For example, a duration field in the first frame may indicate an end moment of the TXOP. As shown in (b) of FIG. 6, the first frame is an ICF. Alternatively, the TXOP of the first frame may be updated by the second station via a CF-End frame. For example, as shown in (a) of FIG. 6, the first frame is an ICF, and the AP 2 indicates an end moment of the TXOP via a duration field in the ICF, and further sends the CF-End frame, indicating that the TXOP ends in advance. That is, the CF-End frame updates the TXOP, and the TXOP of the first frame ends when sending of the CF-End frame is completed.

[0209] If the first station detects, before the end moment of the TXOP of the first frame, the first PPDU that can trigger NPCA, the first station is triggered for NPCA, to be specific, switches from the first primary channel to the second primary channel, where the second primary channel is an NPCA primary channel, for example, an NPCA primary 20 MHz channel different from the primary 20 MHz channel.

[0210] The first PPDU may be a PPDU sent by the second station, or may be a PPDU sent by the station associated with the second station. In other words, a sender of the first PPDU and a sender of the first frame may be the same or different. It should be understood that, for the first station, the first PPDU is an OBSS PPDU, or is referred to as an inter-BSS PPDU (Inter-BSS PPDU).

[0211] For example, the condition for triggering NPCA may include: Duration in which the first PPDU occupies the first primary channel is greater than a second threshold, and a channel occupied by the first PPDU does not overlap (overlap) with the second primary channel. That the channel occupied by the first PPDU does not overlap with the second primary channel may also be described as follows: The first PPDU does not occupy the second primary channel, or the channel occupied by the first PPDU is in a channel other than the second primary channel.

[0212] Optionally, in this application, the "condition for triggering NPCA" may be a condition for triggering NPCA of the first station. For example, conditions for NPCA may be different for different stations. In this case, the "condition for triggering NPCA" mentioned in this application is a condition dedicated to the first station.

[0213] The first PPDU may be a data PPDU, and the first PPDU and the first frame belong to a same TXOP.

[0214] In an implementation, the second threshold may be an NPCA minimum duration threshold (NPCA minimum duration threshold) or a PPDU length-based NPCA minimum duration threshold. The threshold may be defined in a protocol, or may be set by an AP corresponding to the NPCA station. It should be understood that, when the NPCA station is the first AP, the AP corresponding to the NPCA station is the first AP; or when the NPCA station is the first non-AP STA, the AP corresponding to the NPCA station is a station associated with the NAPC station, namely, the first AP. The threshold may be set by the first AP.

[0215] For example, a moment at which the first station starts to switch to the second primary channel is after a start moment of the first PPDU. For example, the moment is after an L-SIG length field in the first PPDU. Because the L-SIG length field may indicate a length of the first PPDU, a value relationship between duration of the first PPDU and the second threshold may be determined. For another example, the moment is after a high efficiency signal A (high efficiency signal A, HE-SIG-A) or U-SIG field in the first PPDU.

[0216] S730: The first station switches from the second primary channel to the first primary channel based on an end moment of the first PPDU.

[0217] Switching from the second primary channel to the first primary channel based on the end moment of the first PPDU may be replaced with completing switching from the second primary channel to the first primary channel not later than the end moment of the first PPDU. Specifically, switching may be completed before the end moment of the first PPDU, or the end moment of the first PPDU may be aligned with a moment at which switching from the second primary channel to the first primary channel is completed. "Aligned" is approximate alignment. As long as a difference between the end moment of the first PPDU and the moment at which switching to the first primary channel is completed is less than specific duration, it may be considered that the two moments are aligned. Alternatively, switching from the second primary channel to the first primary channel based on the end moment of the first PPDU may be replaced with starting, not later than the end moment of the first PPDU, to switch from the second primary channel to the first primary channel. In other words, a switching start moment is before the end moment of the first PPDU, or is aligned with the end moment of the first PPDU.

[0218] For example, the end moment of the first PPDU may be obtained from a length field (namely, the L-SIG length field in the first PPDU) in an L-SIG field in a preamble of the first PPDU.

[0219] For example, S720 and S730 may be considered as an PPDU length-based NPCA (PPDU length-based NPCA) mechanism. To be specific, when a PPDU that meets the condition for triggering NPCA is detected, switching from a primary channel to an NPCA primary channel is performed, and switching back to the primary channel is performed based on an end moment of the PPDU.

[0220] Based on the foregoing solution, when the first station detects exchange of unavailability information by an OBSS station, the first station may enable PPDU length-based NPCA. To be specific, when the PPDU that meets the condition for triggering NPCA is detected, the first station switches from the primary channel to the NPCA primary channel, and switches back to the primary channel based on the end moment of the PPDU. In this way, the first station can switch back to the primary channel in time to perform channel contention, thereby avoiding a waste of transmission resources of the primary channel when an OBSS TXOP on the primary channel ends in advance.

[0221] In addition, because the first station can switch back to the primary channel in time, the first station can learn of a latest status of the primary channel, thereby avoiding losing medium synchronization.

[0222] For example, FIG. 8 is used as an example. An AP 2 sends an ICF to a non-AP STA 2 to query unavailability information of the non-AP STA 2. The non-AP STA 2 replies with an ICR carrying the unavailability information of the non-AP STA 2. Further, the AP 2 sends a downlink PPDU to the non-AP STA 2, and the non-AP STA 2 replies with BA. An AP 1 and a non-AP STA 1 switch to an NPCA primary channel after detecting the downlink PPDU of the AP 2 (for example, at a moment #1), and switch back to a primary channel at an end moment (for example, at a moment #4) of an initial TXOP of the AP 2. Further, based on the unavailability information of the non-AP STA 2, the AP 2 may learn that the non-AP STA 2 is unavailable in this TXOP period of the AP 2. To avoid a failure of transmission between the AP 2 and the non-AP STA 2, the AP 2 sends CF-End before an unavailability start moment of the non-AP STA 2, to end the TXOP in advance. In this case, the AP 1 and the non-AP STA 1 have switched back to the primary channel, and can learn of information that the TXOP ends in advance, and the AP 1 and the non-AP STA 1 may contend for the primary channel after the TXOP ends, to avoid a waste of resources of the primary channel.

[0223] Optionally, the NPCA mechanism shown in (a) and (b) of FIG. 6 may be considered as TXOP length-based NPCA (TXOP length-based NPCA). To be specific, switching to the NPCA primary channel is performed when the condition for triggering NPCA is met, and switching back to the primary channel is performed based on the end moment of the TXOP. In contrast, in PPDU length-based NPCA provided in this application, switching back to the primary channel can be performed based on the end moment ofthe PPDU. PPDU length-based NPCA may also be referred to as PPDU duration-based NPCA (PPDU duration-based NPCA), PPDU-based NPCA (PPDU-based NPCA), PPDU-level NPCA (PPDU-level NPCA), or the like. Similarly, TXOP lengthbased NPCA may also be referred to as TXOP duration-based NPCA (TXOP duration-based NPCA), TXOP-based NPCA (TXOP-based NPCA), TXOP-level NPCA (TXOP-level NPCA), or the like.

[0224] Considering that a plurality of PPDUs may be transmitted in one TXOP, a main difference between TXOP length-based NPCA and PPDU length-based NPCA lies in that moments of switching from the NPCA primary channel back to the primary channel are different. It is assumed that a 1st PPDU in an OBSS TXOP triggers NPCA ofa station. In this case, the station switches to the NPCA primary channel. In a TXOP length-based NPCA mode, the station switches back to the primary channel at an end of the OBSS TXOP. In a PPDU length-based NPCA mode, the station switches back to the primary channel at an end of a 1st OBSS PPDU. A following OBSS PPDU may trigger NPCA of the station again. For example, the station switches to the NPCA primary channel again when a 2nd OBSS PPDU is detected, and then switches back to the primary channel at an end of the 2nd OBSS PPDU.

[0225] It should be understood that, after the first station is triggered for TXOP length-based NPCA, the first station may perform NPCA based on a length of an OBSS TXOP, that is, the first station switches from the NPCA primary channel back to the primary channel based on an end time of the OBSS TXOP. If NPCA is triggered by OBSS control frame exchange, TXOP length information may be obtained from a duration field in a media access control (medium access control, MAC) frame header (header) of a control frame. If NPCA is triggered by an OBSS HE PPDU, TXOP length information may be obtained from a TXOP field in an HE-SIG-A field in a preamble of the PPDU. If NPCA is triggered by an OBSS EHT PPDU or UHR PPDU, TXOP length information may be obtained from a TXOP field in a U-SIG field in a preamble of the PPDU.

[0226] For example, an NPCA minimum duration threshold (denoted as a third threshold) corresponding to TXOP length-based NPCA and an NPCA minimum duration threshold (that is, the second threshold) corresponding to PPDU length-based NPCA may be the same or different. The second threshold and / or the third threshold may be predefined in a protocol, or may be set by the NPCA station or an NPCA-associated station (for example, the first AP).

[0227] The following describes a specific case of the first frame.

[0228] In an implementation 1, the first frame is a first initial control frame ICF, and the first ICF meets at least one of the following conditions:

[0229] (1) The first ICF is a BSRP frame, the BSRP frame includes response type (response type) indication information, and the response type indication information indicates that a response type of a response frame of the first frame is unavailability information feedback (unavailability feedback). The condition (1) may also be understood as that the response type of the ICF is DUO feedback.

[0230] (2) The first ICF is a BSRP frame, the BSRP frame includes ICF type (ICF type) indication information, and the ICF type indication information indicates that the first ICF is used to query unavailability information. The condition (2) may also be understood as that an ICF type is a DUO ICF or an ICF that supports a DUO mode of a non-AP STA.

[0231] (3) The first ICF is a BSRP frame, the BSRP frame includes a GI and HE / UHR-LTF type field, and a value of the GI and HE / UHR-LTF type field is 3. The condition (3) may also be understood as that the ICF is a BSRP GI3 frame, and the BSRP GI3 frame is a BSRP frame that solicits a multi-STA BA frame carried in a non-HT PPDU as a response.

[0232] (4) The first ICF is a BSRP frame, the BSRP frame includes a UL length field, and a value of the UL length field is greater than a first threshold. The condition (4) may be understood as that a response frame of the first ICF needs to be set to be long enough, so that a peer station can include unavailability information in the response frame.

[0233] (5) The first ICF is a BSRP frame, the BSRP frame includes a CS required field, and a value of the CS required field is 1.

[0234] It should be understood that, in this application, the BSRP frame may be replaced with a BSRP trigger frame, and the BSRP GI3 frame may be replaced with a BSRP GI3 trigger frame. In this application, querying the unavailability information may be replaced with soliciting the unavailability information or requesting the unavailability information.

[0235] When the first frame is the ICF and meets at least one of the foregoing conditions, it indicates that the first frame may be an ICF for querying the unavailability information or an ICF for carrying the unavailability information. In this case, the first ICF may be referred to as a DUO ICF, and the first station may determine that there is a possibility of shortening the TXOP of the first frame. Therefore, the first station may enable PPDU length-based NPCA, to switch back to the primary channel in time, thereby avoiding a waste of resources of the primary channel and improving resource utilization.

[0236] In addition, the first station may use information carried in the ICF as a determining condition, and no additional indication information is required. This can avoid a waste of a primary channel access opportunity, and more efficiently use resources of a non-primary channel.

[0237] In addition, the ICF may include more information, and is easier to decode. This can improve processing efficiency of the first station, and reduce power consumption.

[0238] In the foregoing conditions, the response type and the ICF type may correspond to each other. The ICF type indicates that the first ICF is the ICF for querying the unavailability information. Correspondingly, the response type is the unavailability information feedback. When the second AP indicates, in the first ICF, that the response type is the unavailability information feedback, the second non-AP STA replies with the unavailability information after detecting the response type. Similarly, when the second AP indicates, in the first ICF, that the ICF type is the ICF for querying the unavailability information, the second non-AP STA replies with the unavailability information after detecting the ICF type.

[0239] For example, the indication of the response type of the ICF may be carried in a common info field or a special user info field.

[0240] For example, any one of the foregoing BSRPs may include a user information (User Info) field, and an association identifier (association identifier, AID) 12 field in the user info field may be set to an AID of a STA whose unavailability information is queried. For example, when the second AP queries the unavailability information of the second non-AP STA, the AID 12 field in the BSRP may be an AID of the second non-AP STA.

[0241] It should be understood that the first ICF may be sent by the second AP, or may be sent by the second non-AP STA. For example, after the second non-AP STA enables the DUO mode, the second AP, as a TXOP holder, sends the ICF to the second non-AP STA as a start of frame exchange. The ICF is used to query the unavailability information of the second non-AP STA. In this case, the ICF is a BSRP frame. For another example, if the second non-AP STA is a TXOP holder, the second non-AP STA may also actively send an ICF to the second AP, and include the unavailability information of the second non-AP STA in the ICF. In this case, the ICF may be a BSRP frame.

[0242] In an implementation 2, the first frame is used to carry the unavailability information of the second station, the first frame is a first ICR frame, and the first ICR frame meets at least one of the following conditions:

[0243] (1) The first frame is a multi-STA BA frame.

[0244] (2) The first frame is a multi-STA BA frame, and the multi-STA BA frame includes the unavailability information of the second station.

[0245] (3) The first frame is a multi-STA BA frame, and a PPDU carrying the multi-STA BA frame is a non-HT PPDU.

[0246] (4) The first frame is a multi-STA BA frame, and a value of an L-SIG length field in a PPDU carrying the multi-STA BA frame is greater than a first threshold.

[0247] In this application, the ICR frame may be referred to as an ICR for short. Therefore, all ICRs in this specification may represent ICR frames, and all first ICRs may represent first ICR frames.

[0248] For example, the first ICR may be sent by the second non-AP STA. For example, after receiving the ICF sent by the second AP, the second non-AP STA needs to reply with the ICR, and includes the unavailability information in the ICR. In this case, the ICR may be a multi-STA BA frame. For example, the unavailability information is carried in a per association identifier traffic identifier information (per association identifier traffic identifier information, Per AID TID Info) field in the multi-STA BA frame.

[0249] When the first frame is the ICR and meets at least one of the foregoing conditions, it indicates that the first frame may be an ICR for carrying the unavailability information. In this case, the first ICR may be referred to as a DUO ICR, and the first station may determine that there is a possibility of shortening the TXOP of the first frame. Therefore, the first station may enable PPDU length-based NPCA, to switch back to the primary channel in time, thereby avoiding a waste of resources of the primary channel and improving resource utilization.

[0250] In addition, the first station may use information carried in the ICR as a determining condition, and no additional indication information is required. This can avoid a waste of a primary channel access opportunity, and more efficiently use resources of a non-primary channel.

[0251] In an implementation 3, the first frame is a first ICF, the first ICF includes first indication information, and the first indication information indicates whether there is a possibility of updating the transmission opportunity TXOP of the first ICF.

[0252] Whether there is the possibility of updating the TXOP may include one or more of the information, for example, whether duration of the TXOP is shortened, whether the duration of the TXOP is prolonged, and whether a transmission bandwidth in the TXOP is updated.

[0253] For example, the first indication information may be one bit. For example, when the indication bit is set to 1, it indicates that the TXOP of the ICF is definitely not to be shortened, or there is no possibility of shortening. When the indication bit is set to 0, it indicates that whether the TXOP of the ICF is shortened is uncertain, or there is the possibility of shortening. For another example, when the indication bit is set to 1, it indicates that the TXOP may be shortened; or when the indication bit is set to 0, it indicates another case.

[0254] For example, the first indication information may alternatively use more bits, to correspond to a more refined case. For example, two bits are used for indication. When the two bits are set to 0, it indicates that whether the duration and a bandwidth of the TXOP may be updated is uncertain; when the two bits are set to 1, it indicates that whether the duration of the TXOP may be updated is uncertain but a bandwidth is definitely not to be updated; when the two bits are set to 2, it indicates that the duration of the TXOP is definitely not to be updated but whether a bandwidth may be updated is uncertain; or when the two bits are set to 3, it indicates that neither the duration nor a bandwidth of the TXOP is updated.

[0255] It should be understood that the foregoing specific indication manner of the first indication information is merely an example for description, and this application is not limited to the foregoing manner.

[0256] When the first indication information indicates that there is the possibility of updating the transmission opportunity TXOP of the first ICF, the first station may enable PPDU lengthbased NPCA, that is, perform S720 and S730 until an end moment of the TXOP indicated in the ICF or until the first station receives a CF-End frame. Alternatively, when the first indication information indicates that there is the possibility of updating the transmission opportunity TXOP of the first ICF, the first station may not perform NPCA, that is, always stay on the primary channel and not perform channel switching until an end moment of the TXOP indicated in the ICF or until the first station receives a CF-End frame. When the first indication information indicates that there is no possibility of updating the transmission opportunity TXOP of the first ICF, the first station may enable TXOP length-based NPCA until an end moment of the TXOP.

[0257] It should be noted that, when the first indication information indicates that there is the possibility of updating the transmission opportunity TXOP of the first ICF, the OBSS may update NAV information in frame exchange. For example, an NAV end moment indicated in the ICR is earlier than an NAV end moment indicated in the ICF, or an NAV end moment indicated in the PPDU after the ICR is earlier than an NAV end moment indicated in the ICR. If the station still needs to perform TXOP length-based NPCA in this case, the station may perform NPCA based on an updated TXOP length. For example, the station is triggered for NPCA by an OBSS ICF, but does not start to switch to the NPCA primary channel, until a moment after the ICR is received. If the received ICR indicates an earlier NAV end moment, duration of staying on the NPCA primary channel is set based on an updated NAV.

[0258] For example, the first ICF may be a BSRP frame, and the first indication information is carried in a common information field or special user information field in the BSRP frame; or the first ICF is an MU-RTS frame, and the first indication information is carried in a common information field or special user information field in the MU-RTS frame.

[0259] FIG. 9 is a diagram of a common information field and special user information field in an ICF according to an embodiment of this application. As shown in (a) of FIG. 9, B22, B26, B53, and B61 to B63 in the common information field are currently reserved bits, and the first indication information may be located in any one of the foregoing bits. As shown in (b) of FIG. 9, B37 to B39 in the special user information field are currently reserved bits, and the first indication information may be located in any one of the foregoing bits.

[0260] Based on the foregoing solution, the first indication information is added to the first ICF, so that another station can clearly learn whether a TXOP of the second station may be updated, and the first station can perform corresponding NPCA behavior based on the first indication information, thereby improving channel utilization efficiency.

[0261] Optionally, the first indication information may further indicate that the second station allows the first station to reset an NAV timer set based on the first frame. For example, in BSRP, the indication may also indicate whether NAV reset is allowed. When there is the possibility of shortening the TXOP, it also indicates that NAV reset is allowed. When there is no possibility of shortening the TXOP, NAV reset is not allowed. The reason for such setting is that NAV reset can only occur when the TXOP is terminated in advance.

[0262] Optionally, the method 700 further includes: The first station determines, based on the first indication information, whether to perform opportunistic power save in the TXOP of the first ICF.

[0263] Specifically, if the first indication information indicates that there is no possibility of shortening the TXOP, the first station may perform TXOP length-based NPCA and opportunistic power save in the TXOP until the end moment of the TXOP indicated in the ICF. This can prevent the first station from frequently performing channel switching, thereby reducing overheads. If the first indication information indicates that there is the possibility of shortening the TXOP, the first station may perform PPDU length-based NPCA until the end moment of the TXOP indicated in the ICF or until the CF-End frame is received. This can prevent the first station from missing necessary information and losing medium synchronization, thereby reducing power consumption without wasting the primary channel access opportunity. Alternatively, if the first indication information indicates that there is the possibility of shortening the TXOP, the first station may not perform NPCA. In this way, the first station may not perform opportunistic power save.

[0264] In an implementation 4, the first frame is a first ICF, the first ICF includes second indication information, and the second indication information indicates a type of NPCA performed in a TXOP of the first ICF by a station in an OBSS of the BSS to which the second station belongs.

[0265] In this application, the type of NPCA may also be referred to as an NPCA mode, an NPCA form, or the like. This is not limited.

[0266] Specifically, the second indication information may indicate a type of NPCA of the OBSS station. The type may include PPDU length-based NPCA, TXOP length-based NPCA, no NPCA, or the like. The following separately provides three specific indication manners of the second indication information, which may be implemented by one bit or two bits.

[0267] Manner 1: One bit is used for indication.

[0268] When the indication bit is set to 1, if a station is triggered for NPCA by the ICF, TXOP length-based NPCA should be performed. When the indication bit is set to 0, if a station is triggered for NPCA by the ICF, PPDU length-based NPCA should be performed.

[0269] Manner 2: One bit is used for indication.

[0270] When the indication bit is set to 0, a station should not be triggered for NPCA by the ICF. When the indication bit is set to 1, if a station is triggered for NPCA by the ICF, TXOP lengthbased NPCA should be performed.

[0271] Manner 3: Two bits are used for indication. When the indication bits are set to 0, a station should not be triggered for NPCA by the ICF. When the indication bits are set to 1, if a station is triggered for NPCA by the ICF, PPDU length-based NPCA should be performed. When the indication bits are set to 2, if a station is triggered for NPCA by the ICF, TXOP length-based NPCA should be performed. When the indication bits are set to 3, a meaning is reserved (which may be used for another purpose later).

[0272] It should be understood that the foregoing specific indication manner of the second indication information is merely an example for description, and this application is not limited to the foregoing manner.

[0273] For example, the first ICF is a BSRP frame, and the second indication information is carried in a common information field or special user information field in the BSRP frame; or the first ICF is an MU-RTS frame, and the second indication information is carried in a common information field or special user information field in the MU-RTS frame.

[0274] Formats of the common information field and special user information field in the ICF are shown in FIG. 9. Similar to the first indication information, the second indication information may also be located in any reserved bit in the common information field or the special user information field.

[0275] Based on the foregoing solution, after detecting the ICF, another station (for example, the first station) may determine, according to the foregoing indication, which type of NPCA is to be performed or whether NPCA is to be performed, so that the first station can clearly learn, based on this indication bit, which type of NPCA should be performed. This avoids a waste of a primary channel access opportunity, and maximizes utilization efficiency of resources of the NPCA primary channel.

[0276] In an implementation 5, the first PPDU includes first indication information and / or second indication information, the first indication information indicates whether there is a possibility of updating a transmission opportunity TXOP of the first PPDU, the second indication information indicates a type of NPCA performed in a TXOP of the first PPDU by a station in an OBSS of the BSS to which the second station belongs, and the TXOP of the first PPDU and the TXOP of the first frame are a same TXOP.

[0277] Specifically, the first indication information and / or the second indication information may be directly located in the first PPDU, for example, carried in a preamble of the first PPDU, like a U-SIG field or a UHR signal (UHR signal, UHR-SIG) field. In this way, when the first station is triggered for NPCA by the first PPDU, the first station may obtain an indication indicating whether the TXOP is to be updated, or may obtain the type of NPCA, so that the first station performs NPCA of the corresponding type, or does not perform NPCA, thereby improving channel utilization efficiency.

[0278] For specific indication manners and meanings of the first indication information and the second indication information, refer to the implementation 3 and the implementation 4.

[0279] In an implementation 6, the first station is a first non-AP STA or a first AP. Before S710, the method 700 further includes: The first AP sends second indication information to the first nonAP STA on the first primary channel. Correspondingly, the first non-AP STA receives the second indication information on the first primary channel.

[0280] The second indication information of a non-AP STA indicates a type of NPCA of a nonAP STA associated with the first AP, and the non-AP STA associated with the first AP includes the first non-AP STA.

[0281] Specifically, when determining that the OBSS station (for example, the second station) enables the DUO mode, the first AP may send the second indication information on the first primary channel. The second indication information indicates the type of NPCA of the non-AP STA associated with the first AP, or indicates a type of NPCA of a station in the first BSS, and the first BSS is a BSS to which the first non-AP STA and the first AP belong. For example, the second indication information may indicate at least one of the following types of NPCA:

[0282] (1) NPCA of a station in the BSS is disabled, or the station in the first BSS is prohibited from performing NPCA, or it indicates the station in the first BSS not to perform NPCA.

[0283] (2) A station in the BSS is limited to perform only PPDU length-based NPCA, or the second indication information indicates that the type of NPCA of the station in the first BSS is PPDU length-based NPCA.

[0284] (3) The second indication information indicates that the non-AP STA associated with the first AP should not be triggered for NPCA by an OBSS. Whether a BSS is the OBSS may be determined by notifying a BSSID or BSS color of the OBSS (for example, the BSS to which the second station belongs).

[0285] (4) The second indication information indicates that the non-AP STA associated with the first AP can be triggered for NPCA by only an OBSS in a list for, and the list does not include the OBSS.

[0286] (5) The second indication information indicates that only PPDU length-based NPCA can be triggered for the non-AP STA associated with the first AP when the OBSS is detected.

[0287] For example, the second indication information may be carried in a beacon (beacon) frame or a probe response (probe response) frame sent by the first AP.

[0288] Optionally, when determining that the second station does not enable the DUO mode, the first AP may send the second indication information on the first primary channel, where the second indication information may indicate that the type of NPCA of the non-AP STA associated with the first AP is TXOP length-based NPCA; or the first AP may not send the second indication information.

[0289] The first AP may determine, in any one of the following manners, whether the second station enables the DUO mode.

[0290] Manner a: Whether the second station enables the DUO mode is determined via an ICF or ICR is sent by the second station. The ICF or ICR may be sent before the first frame. For example, the second AP sends a second ICF in a TXOP before the TXOP of the first frame, and the second ICF may be used to query whether the second non-AP STA has the unavailability information. The second non-AP STA replies with a second ICR, and includes the unavailability information of the second non-AP STA. Based on the second ICF or the second ICR, the first AP may determine that the second non-AP STA enables the DUO mode. Therefore, the second indication information may be sent to the first non-AP STA before S710.

[0291] Manner b: The first AP detects at least one of a beacon frame, a probe response frame, or another management frame of the second BSS. Specifically, if the second AP or the second nonAP STA in the second BSS enables the DUO mode, the second AP may perform indication via at least one of the beacon frame, the probe response frame, or the another management frame. Therefore, the first AP can determine, by detecting the beacon frame, the probe response frame, or the another management frame of the second BSS, whether the second station enables the DUO mode.

[0292] Manner c: The non-AP STA associated with the first AP may also detect whether the second station enables the DUO mode, and may report to the first AP, so that the first AP can determine whether the second station enables the DUO mode.

[0293] Optionally, in this implementation, when the first AP indicates the type of NPCA to the first non-AP STA, the first non-AP STA may always perform NPCA based on the type of NPCA indicated by the first AP, until the first AP sends new second indication information.

[0294] It should be understood that the foregoing implementations may be used in combination, and are jointly used by the first station to determine whether to enable PPDU length-based NPCA. The following provides descriptions by using examples.

[0295] In an example, various conditions in the implementation 1 and the implementation 2 may be combined. For example, when the second AP sends the first ICF to query the unavailability information of the second non-AP STA, it may explicitly indicate, in the first ICF, that the response type of the ICF is unavailability information feedback. When detecting that the response type of the first ICF is unavailability information feedback, the second non-AP STA replies with the multi-STA BA frame as the first ICR, and includes the unavailability information of the second non-AP STA in the multi-STA BA frame. For another example, it may also indicate a type of the ICF in the first ICF, for example, indicate that the type of the ICF is an ICF for querying the unavailability information. After detecting the type of the ICF, the second non-AP STA replies with the unavailability information via the first ICR. In the two examples, the first station may receive both the first ICF and the first ICR, and further determine, based on both the first ICF and the first ICR, to enable PPDU length-based NPCA.

[0296] In another example, the implementation 1 and the implementation 3 may be combined. For example, the first AP sends an ICF, where the ICF is BSRP, a response type is unavailability information, and it indicates that the ICF is used to query unavailability information. The second AP may include the first indication information in the ICF, to indicate that there is a possibility of shortening the TXOP. In this case, the first station may determine, based on the first ICF, PPDU length-based NPCA. For another example, if the second AP protects a channel from interference via an ICF, and determines that the entire TXOP is used for transmission, the ICF is not used to query unavailability information, and the ICF carries the first indication information, to indicate that there is no possibility of shortening the TXOP. In this case, the first station may determine, based on the first ICF, TXOP length-based NPCA.

[0297] In another example, the implementation 1 and the implementation 4 may be combined. For example, when the second AP sends an ICF, a bit value of the second indication information needs to be set by considering a type of the ICF and a feature of a TXOP of the ICF. For example, if the indication manner 1 is used for the second indication information and the ICF is used to query the unavailability information of the second non-AP STA, the second indication information is set to 0, indicating that the NPCA station should perform PPDU length-based NPCA.

[0298] Similarly, other different implementations may also be combined with each other. Details are not described herein.

[0299] Optionally, the foregoing implementations may also be decoupled from the method 700 and implemented independently. The following provides examples for description.

[0300] For example, the implementation 3 may be implemented independently. Specifically, the second station may generate a first ICF, and send the first ICF. The first ICF includes first indication information, and the first indication information indicates whether there is a possibility of updating a TXOP of the first ICF. A station (for example, the first station) receiving the first ICF may learn whether there is the possibility of updating the TXOP of the first ICF. Further, the first station may perform PPDU length-based NPCA in the method 700, or may perform another operation related to or unrelated to NPCA.

[0301] For another example, the implementation 4 may be implemented independently. Specifically, the second station may generate a first ICF, and send the first ICF. The first ICF includes second indication information, and the second indication information indicates a type of NPCA performed in a TXOP of the first ICF by a station in an OBSS of the BSS to which the second station belongs. A station (for example, the first station) receiving the first ICF may learn of a type of NPCA that should be performed in the TXOP of the first ICF. Further, the first station may perform PPDU length-based NPCA in the method 700, or may perform another operation related to or unrelated to NPCA.

[0302] For another example, the implementation 5 may be implemented independently. Specifically, the second station may generate a first PPDU, and send the first PPDU. The first PPDU includes first indication information and / or second indication information. The first indication information indicates whether there is a possibility of updating a TXOP of the first PPDU. The second indication information indicates a type of NPCA performed in the TXOP of the first PPDU by a station in an OBSS of the BSS to which the second station belongs. A station (for example, the first station) receiving the first PPDU may learn, based on the first indication information, whether there is the possibility of updating the TXOP of the first PPDU, and learn, based on the second indication information, a type of NPCA that should be performed in the TXOP of the first PPDU. Further, the first station may perform PPDU length-based NPCA in the method 700, or may perform another operation related to or unrelated to NPCA. Optionally, the foregoing first frame may be encapsulated in the first PPDU.

[0303] For another example, the implementation 6 may be implemented independently. Specifically, the first AP may generate a beacon frame, a probe response frame, or another management frame, and send the beacon frame, the probe response frame, or the another management frame. The beacon frame, the probe response frame, or the another management frame includes second indication information, and the second indication information indicates a type of NPCA of a non-AP STA associated with the first AP. A station (for example, the first nonAP STA) receiving the second indication information may learn of a type of NPCA that should be performed. Further, the first non-AP STA may perform PPDU length-based NPCA in the method 700, or may perform another operation related to or unrelated to NPCA.

[0304] It should be understood that, in this application, "not performing NPCA" may be considered as a type of NPCA, that is, may be considered as an operation related to NPCA, or may be considered as an operation unrelated to NPCA. This is not limited.

[0305] Optionally, in an alternative solution of the method 700, S710 may not be performed, to be specific, the first station performs PPDU length-based NPCA by default. Provided that the first PPDU meets the condition for triggering NPCA, the first station may switch from the primary channel to the NPCA primary channel when detecting the PPDU, and switch back to the primary channel based on the end moment of the PPDU.

[0306] Optionally, in an alternative solution of the method 700, when the first frame meets the condition in the implementation 2, the first station may further perform NPCA based on the first frame (namely, the first ICR). For example, a time for staying on the NPCA primary channel may be set based on NAV information indicated by a duration field in the first ICR.

[0307] Specifically, in some cases, the first station can detect only the OBSS ICR (namely, the first ICR), but cannot detect the first ICF. For example, the second AP communicates with the second non-AP STA, the second AP sends the first ICF, the second non-AP STA replies with the first ICR, and the first station can detect only a frame of the second non-AP STA (in other words, the second AP is a hidden node in the first BSS). Therefore, the first ICR is detected. In a manner, NPCA of the first station may be triggered by detecting only the OBSS ICR. In this case, length information of the OBSS TXOP may be learned of from the duration field in the ICR. However, if the ICR is a multi-STA BA frame, considering that the multi-STA BA may be used to carry the unavailability information of the second non-AP STA and the second AP may directly terminate the TXOP based on the unavailability information, the first station cannot determine, based on only the first ICR, whether the second AP or the second non-AP STA continues to perform transmission. If the first station performs NPCA, a primary channel access opportunity may be wasted. Therefore, the following rules may be introduced:

[0308] If the first station detects only the OBSS ICR but does not detect an ICF corresponding to the OBSS ICR, and the ICR meets at least one condition in the implementation 2, NPCA of the first station needs to comply with the following rule 1 or rule 2:

[0309] Rule 1: NPCA is not performed unless an OBSS PPDU following the OBSS ICR is detected.

[0310] Rule 2: If a BSRP frame corresponding to the ICF allows NAV reset (NAV reset), NPCA is not performed unless an OBSS PPDU following the OBSS ICR is detected. If a BSRP frame corresponding to the ICF does not allow NAV reset, NPCA may be performed based on the OBSS ICR, and the time for staying on the NPCA primary channel may be set based on the NAV information indicated by the duration field in the ICR.

[0311] The foregoing rule 1 directly prohibits the first station from performing NPCA behavior based on only the OBSS ICR that meets the foregoing condition. This is because whether the OBSS TXOP continues cannot be determined unless the following OBSS PPDU (for example, the first PPDU) is detected. In this case, staying on the primary channel helps obtain a primary channel access opportunity. If the station detects the PPDU (for example, the first PPDU) following the OBSS ICR, NPCA may still be performed. For example, PPDU length-based NPCA may be performed, that is, the implementation 2 in the method 700, or TXOP length-based NPCA may be performed.

[0312] Whether the BSRP frame allows NAV reset is considered in the foregoing rule 2. NAV reset means that, if the station detects an OBSS ICF but does not detect a following PPDU, the station may reset, after timeout (NAVTimeout), an NAV set by the ICF to 0, to participate in channel contention. If NAV reset is allowed and transmission is stopped in the OBSS after the ICF, the station may contend for the primary channel after NAVTimeout. Therefore, not performing NPCA based on the ICR helps obtain a primary channel access opportunity. If NAV reset is not allowed, even if transmission is stopped in the OBSS after the ICF, an NAV of the station is not reset, and the station cannot contend for the primary channel before the NAV is reset to 0. Therefore, switching to the NPCA primary channel helps improve channel utilization efficiency.

[0313] Optionally, in an alternative solution of the method 700, when the first frame meets the condition in the implementation 1 or the implementation 2 and the first frame includes the unavailability start moment, the first station may switch from the second primary channel to the first primary channel based on the unavailability start moment. In this case, the first frame in S710 includes the unavailability start moment, and S730 may be replaced with: The first station switches from the second primary channel to the first primary channel based on the unavailability start moment.

[0314] In other words, if the first frame indicates the unavailability start moment and the unavailability start moment is earlier than the end moment of the TXOP of the first frame, the first station may switch from the NPCA primary channel back to the primary channel before the unavailability start moment. In this way, the NPCA primary channel can be used more efficiently. Specifically, even if the second station shortens the TXOP due to the DUO, a shortened part also belongs to an unavailability time period of the OBSS station. Therefore, the primary channel is still always occupied by the OBSS before the unavailability start moment of the OBSS station, and the first station can still perform NPCA in this time period. However, the first station switches back to the primary channel at the unavailability start moment of the OBSS station, so that the first station can learn of a status of the primary channel in time, and the first station can also contend for the primary channel earlier when an OBSS TXOP is terminated in advance.

[0315] In the alternative solution, the first frame may be a first ICR, the first ICR frame is a multi-STA BA frame, and a PPDU carrying the multi-STA BA frame is a non-HT PPDU. In this way, the first station can decode the first frame to obtain the unavailability start moment.

[0316] Optionally, in an alternative solution of the method 700, when the first frame meets the condition in the implementation 1 or the implementation 2, the first station may not perform NPCA. In this case, S720 and S730 may be replaced with: Stop performing NPCA before an end indication of the TXOP of the first frame is received; or stop performing NPCA before countdown of the NAV timer set based on the first frame ends. This can avoid a waste of resources of the primary channel, that is, can avoid a waste of a primary channel access opportunity because the first station switches to the NPCA primary channel when a TXOP of the second station ends in advance.

[0317] FIG. 10 is a schematic flowchart of a communication method 1000 according to this application. The method may be used to resolve a problem that occurs when an NPCA mechanism and a Co-BF mechanism or Co-SR mechanism coexist. As shown in FIG. 10, the method 1000 includes the following steps.

[0318] S1010: A second station sends a second frame on a first primary channel, and correspondingly, a first station receives the second frame on the first primary channel, where the second frame is used to transmit control information in a first multi-AP coordination procedure, and the second station participates in the first multi-AP coordination procedure.

[0319] In this application, a multi-AP coordination procedure may also be referred to as a multi-AP coordination mechanism. Therefore, the first multi-AP coordination procedure may be referred to as a first multi-AP coordination mechanism, for example, a Co-SR procedure or a Co-BF procedure. Specifically, the first multi-AP coordination procedure may be a Co-SR transmission procedure, or may be a Co-BF transmission procedure, or may be a Co-BF sounding procedure.

[0320] In the method 1000, the second station may be a station participating in the first multi-AP coordination procedure, or the second station is related to the first multi-AP coordination procedure. Therefore, the second frame may be a frame in the first multi-AP coordination procedure. Specifically, the second frame is a frame that is exchanged between the second station and a station associated with the second station in the first multi-AP coordination procedure and that is used to transmit the control information.

[0321] For example, the second station is a second AP, the first multi-AP coordination procedure is a Co-BF procedure, and the second frame may be an ICF in the Co-BF procedure. Specifically, when the second AP is a sharing AP, the second frame may be a Co-BF invite frame or an ICF 1 in FIG. 3, for example, a sounding invite frame or an ICF in FIG. 4. When the second AP is a shared AP, the second frame may be a Co-BF response frame or an ICF 2 in FIG. 3, for example, a sounding response frame in FIG. 4.

[0322] For another example, the second station is a second non-AP STA, the first multi-AP coordination procedure is a Co-BF procedure, and the second frame may be an ICR in the Co-BF procedure. Specifically, when the AP associated with the second non-AP STA is a sharing AP, the second frame may be an ICR 1 in FIG. 3 or an ICR in FIG. 4. When the AP associated with the second non-AP STA is a shared AP, the second frame may be an ICR 2 in FIG. 3.

[0323] For another example, the second station is a second AP, the first multi-AP coordination procedure is a Co-SR procedure, and the second frame may be an ICF in the Co-SR procedure. Specifically, when the second AP is a sharing AP, the second frame may be a Co-SR invite frame, an ICF 1, or the like in FIG. 5. When the second AP is a shared AP, the second frame may be a CoSR response frame, an ICF 2, or the like in FIG. 5.

[0324] For another example, the second station is a second non-AP STA, the first multi-AP coordination procedure is a Co-SR procedure, and the second frame may be an ICR in the Co-SR procedure. Specifically, when the AP associated with the second non-AP STA is a sharing AP, the second frame may be an ICR 1 in FIG. 5. When the AP associated with the second non-AP STA is a shared AP, the second frame may be an ICR 2 in FIG. 5.

[0325] For example, the Co-BF invite frame, the sounding invite frame, and the Co-SR invite frame may be BSRP frames, and the Co-BF response frame, the sounding response frame, and the Co-SR response frame may be multi-STA BA frames.

[0326] The first station may be referred to as an NPCA station. Specifically, the first station may be a first AP, or may be a first non-AP STA. The first non-AP STA is associated with the first AP.

[0327] In addition, a BSS to which the first non-AP STA and the first AP belong may be denoted as a first BSS, and a BSS to which the second non-AP STA and the second AP belong may be denoted as a second BSS. The first BSS and the second BSS are OBSSs of each other.

[0328] A BSS to which the second station belongs and a BSS to which the first station belongs are OBSSs of each other. In other words, the second station is an OBSS station of the first station. Therefore, the first station can receive the second frame, and obtain a part or all of information in the second frame through parsing. Specifically, the first station may determine, by detecting a type indication of the second frame, whether the second frame is a frame in the Co-SR procedure or the Co-BF procedure, or whether the second frame is used in the Co-SR procedure or the Co-BF procedure.

[0329] It should be understood that a PPDU is from a BSS (that is, an intra-BSS PPDU) or an OBSS (that is, an inter-BSS PPDU) may be determined based on a basic service set identifier (basic service set identifier, BSSID) or a BSS color. The BSSID includes 48 bits, and may be carried in a MAC frame header. The BSS color includes six bits, and is carried in a preamble of an HE PPDU, an EHT PPDU, or a UHR PPDU. Different BSS colors are usually set for different BSSs. Based on the BSS color, the first station may distinguish that a received PPDU is from the BSS or the OBSS. In the Co-SR procedure or the Co-BF procedure, a preamble of a downlink data PPDU may include BSS colors of all APs participating in the Co-SR procedure or the Co-BF procedure.

[0330] S1020a: The first station switches from the first primary channel to a second primary channel when the first station does not participate in the first multi-AP coordination procedure and it is detected that a first PPDU meets a condition for triggering NPCA, where the second primary channel is an NPCA primary channel.

[0331] For descriptions of the first primary channel and the second primary channel and descriptions of the condition for triggering NPCA, refer to the method 700. Details are not described herein again.

[0332] The first PPDU is a downlink data PPDU in the first multi-AP coordination procedure, for example, a Co-BF data PPDU or a Co-SR data PPDU. The Co-BF data PPDU may also be referred to as a Co-BF PPDU or a Co-BF DL PPDU, and the Co-SR data PPDU may also be referred to as a Co-SR PPDU or a Co-SR DL PPDU. In addition, the first PPDU may be sent by a sharing AP, or may be sent by a shared AP.

[0333] In other words, the first station may be a station that does not participate in the first multi-AP coordination procedure, or the first station is unrelated to the first multi-AP coordination procedure. Only when detecting the downlink data PPDU in the first multi-AP coordination procedure, the first station starts to switch from the first primary channel to the second primary channel.

[0334] For example, after detecting a universal signal field U-SIG in the first PPDU, the first station may start to switch from the first primary channel to the second primary channel. Specifically, a moment at which switching from the first primary channel to the second primary channel starts is any one of the following: (1) a moment at which signal time (SIG_TIME) expires from a start moment of the first PPDU, in other words, switching starts after SIG_TIME elapses from the start moment of the first PPDU; (2) a moment at which SIG_TIME and a slot time (aSlotTime) expire from a start moment of the first PPDU, in other words, switching starts after SIG_TIME and the slot time elapse from the start moment of the first PPDU; or (3) a moment at which SIG_TIME, a receiver physical layer start delay (aRxPHYStartDelay), and a slot time expire from a start moment of the first PPDU, in other words, switching starts after SIG_TIME, aRxPHYStartDelay, and the slot time elapse from the start moment of the first PPDU.

[0335] SIG_TIME is duration from a start of the PPDU to an end of an HE-SIG-A field or a U-SIG field, and is usually 32 microseconds (gs). aSlotTime and aRxPHYStartDelay are values defined in the IEEE 802.11 protocol.

[0336] Corresponding to the foregoing three options, if the switching start moment starts from an end moment of a Co-BF trigger frame or a Co-SR trigger frame, only a short interframe space (short interframe space, SIFS) time (aSIFSTime) needs to be added to duration in each of the foregoing three options, where aSIFSTime is a value defined in the IEEE 802.11 protocol.

[0337] In the foregoing three options, switching to the NPCA primary channel starts after a U-SIG field in a preamble of the first PPDU is detected. In the options 2 and 3, additional duration is added. This can ensure the first station can have a sufficient time to determine whether to perform NPCA.

[0338] Based on the foregoing solution, because the U-SIG field and a field preceding the U-SIG field include necessary information for determining whether to perform NPCA, for example, an L-SIG field preceding the U-SIG field includes a length field, and the U-SIG field includes a TXOP field and a BSS color field, after detecting the U-SIG field in the first PPDU, the first station starts to switch, to obtain the necessary information for determining whether to perform NPCA, to help the first station make a decision.

[0339] For example, the first PPDU includes N BSS colors, and the N BSS colors include a BSS color of a BSS to which a station participating in the first multi-AP coordination procedure belongs. When the first station does not participate in the first multi-AP coordination procedure, all the N BSS colors are different from a BSS color of the BSS to which the first station belongs; or when the first station does not participate in the first multi-AP coordination procedure, the N BSS colors include a BSS color of the BSS to which the first station belongs. N is an integer greater than or equal to 2. In other words, the first station may determine, based on the BSS color included in the first PPDU, whether the first station participates in the first multi-AP coordination procedure.

[0340] Specifically, because the first PPDU is the downlink data PPDU in the first multi-AP coordination procedure, the U-SIG field in the first PPDU includes BSS colors of all APs participating in the first multi-AP coordination procedure. For example, there are N APs participating in the first multi-AP coordination procedure. In this case, the first PPDU includes the N BSS colors, and the N BSS colors include a second BSS color of the second station. The first station may parse the U-SIG field, and compare the N BSS colors with the BSS color of the first station one by one. If all the N BSS colors different from the BSS color of the first station, it indicates that the first station is unrelated to the first multi-AP coordination procedure, and the first station may be triggered for NPCA. If one of the N BSS colors is the same as the BSS color of the first station, it indicates that the first station is related to the first multi-AP coordination procedure, and the first station is not triggered for NPCA.

[0341] For example, there are two APs participating in the first multi-AP coordination procedure, that is, N=2, BSS colors of the two APs are denoted as a BSS color 1 and a BSS color 2. When the BSS color of the BSS to which the first station belongs is different from the BSS color 1, and is also different from the BSS color 2, it indicates that the first station is unrelated to the first multi-AP coordination procedure.

[0342] Optionally, the method 1000 may also be understood as follows: Even if the second frame meets the condition for triggering NPCA and the first station is unrelated to the first multi-AP coordination procedure in which the second frame is, the first station does not switch to the second primary channel immediately after the second frame, but starts, when detecting the downlink data PPDU in the first multi-AP coordination procedure, to switch from the first primary channel to the second primary channel. Alternatively, it is understood that the second frame cannot meet the condition for triggering NPCA. Therefore, the first station performs NPCA when detecting that the first PPDU meets the condition for triggering NPCA.

[0343] S1020b: The first station stays on the first primary channel in a TXOP of the first multi- AP coordination procedure when the first station participates in the first multi-AP coordination procedure and a second frame or a first PPDU is detected, and does not perform NPCA.

[0344] Specifically, the first station may participate in the first multi-AP coordination procedure. For example, the first station is a first AP, and the first AP participates in the first multi-AP coordination procedure. Alternatively, the first station is a first non-AP STA, and a first AP associated with the first non-AP STA participates in the first multi-AP coordination procedure.

[0345] S1020b may also be understood as follows: When the first station participates in the first multi-AP coordination procedure, neither a control frame (for example, the second frame) in the first multi-AP coordination procedure nor a downlink data PPDU (for example, the first PPDU) in the first multi-AP coordination procedure triggers the first station to perform NPCA. This can ensure that the first multi-AP coordination procedure in which the first station participates is normally performed.

[0346] Based on the foregoing solution, when the first station does not participate in a first multi-AP coordination procedure that is being performed by an OBSS station, the first station may start, after detecting a downlink data PPDU of the OBSS station, to switch to the NPCA primary channel. When the first station participates in the first multi-AP coordination procedure, the first station does not perform NPCA in the TXOP of the first multi-AP coordination procedure. In other words, an OBSS control frame or the downlink data PPDU in the multi-AP coordination procedure in which the first station participates cannot trigger the first station to switch to the NPCA primary channel. The first station switches to the NPCA primary channel only when detecting a downlink data PPDU in a multi-AP coordination procedure in which the first station does not participate. This can prevent the first station from switching to the NPCA primary channel when necessary, thereby avoiding a transmission failure in the multi-AP coordination procedure in which the first station participates, and avoiding a waste of transmission resources of the primary channel.

[0347] Optionally, when the first station does not participate in the first multi-AP coordination procedure, the first station and a third station may participate in a second multi-AP coordination procedure.

[0348] For example, the first station is a first AP, the third station is a third AP, and the first AP and the third AP participate in the second multi-AP coordination procedure; or the first station is a first non-AP STA, the third station is a third non-AP STA, and a first AP associated with the first non-AP STA and a third AP associated with the third non-AP STA participate in the second multi-AP coordination procedure.

[0349] In this case, the method 1000 may be understood as follows: When the first station detects the second frame in the first multi-AP coordination procedure, and a third frame or second PPDU in the second multi-AP coordination procedure, the first station does not perform NPCA; or when the first station detects the first PPDU in the first multi-AP coordination procedure, the first station performs NPCA. The third frame is used to transmit control information in the second multi-AP coordination procedure. For example, the third frame is an ICF in Co-BF, an ICR in Co-BF, an ICF in Co-SR, or an ICR in Co-SR. For details, refer to the foregoing description of the second frame. The second PPDU is a downlink data PPDU in the second multi-AP coordination procedure. For details, refer to the description of the first PPDU in the method 1000. In other words, when the first station participates in the second multi-AP coordination procedure, a control frame in the first multi-AP coordination procedure, a control frame in the second multi-AP coordination procedure, or a downlink data PPDU in the second multi-AP coordination procedure does not trigger the first station to switch to the NPCA primary channel. This can ensure that the second multi-AP coordination procedure in which the first station participates is normally performed. However, a downlink data PPDU in the first multi-AP coordination procedure triggers the first station to switch to the NPCA primary channel, thereby avoiding interference.

[0350] For example, FIG. 11 is used as an example. An AP 1 and an AP 2 are performing a first Co-BF procedure, the AP 1 is a sharing AP, and the AP 2 is a shared AP. An AP 3 and an AP 4 are performing a second Co-BF procedure, the AP 3 is a sharing AP, and the AP 4 is a shared AP. A non-AP STA 1 is associated with the AP 1, a non-AP STA 2 is associated with the AP 2, a nonAP STA 3 is associated with the AP 3, and a non-AP STA 4 is associated with the AP 4. The AP 1 and the non-AP STA 1 communicate with each other on the primary channel, and the AP 2 and the non-AP STA 2 also communicate with each other on the primary channel. For the non-AP STA 2 (an example of the first station), because the non-AP STA 2 participates in the first Co-BF procedure, a Co-BF invite frame, an ICF 1, and a downlink data PPDU 1 that are in the first Co-BF procedure do not trigger the non-AP STA 2 to switch to the NPCA primary channel. This can ensure that the first multi-AP coordination procedure is normally performed. Similarly, for the non-AP STA 4 (another example of the first station), because the non-AP STA 4 participates in the second Co-BF procedure, a Co-BF invite frame, an ICF 1, and a downlink data PPDU 1 that are in the second Co-BF procedure do not trigger the non-AP STA 4 to switch to the NPCA primary channel. This can ensure that the second multi-AP coordination procedure is normally performed. It should be understood that the Co-BF invite frame, the ICF 1, and the downlink data PPDU 1 that are in the second Co-BF procedure are not shown in FIG. 11.

[0351] However, for the non-AP STA 4 (another example of the first station), because the nonAP STA 4 does not participate in the first Co-BF procedure, the downlink data PPDU 1 or a downlink data PPDU 2 in the first Co-BF procedure triggers the non-AP STA 4 to switch to the NPCA primary channel. For example, the non-AP STA 4 may switch to the NPCA primary channel at a moment #1. Similarly, stations participating in the second Co-BF procedure, such as the AP 3, the AP 4, and the non-AP STA 3, are triggered for NPCA by the downlink data PPDU 1 or the downlink data PPDU 2 in the first Co-BF procedure, to switch to the NPCA primary channel. This can avoid interference between the first multi-AP coordination procedure and the second multi-AP coordination procedure.

[0352] Optionally, the AP 3, the AP 4, the non-AP STA 3, and the non-AP STA 4 may switch back to the primary channel at an end moment of the downlink data PPDU 2, or may switch back to the primary channel at an end moment of a TXOP of the first Co-BF procedure. For details, refer to S1030a and S1030b below. FIG. 11 shows a case of switching back to the primary channel at the end moment of the downlink data PPDU 2.

[0353] Optionally, in an implementation scenario, when the method 1000 includes S1020a, the method 1000 further includes: S1030a: The first station switches from the second primary channel to the first primary channel based on an end moment of the TXOP of the first multi-AP coordination procedure.

[0354] Switching from the second primary channel to the first primary channel based on the end moment of the TXOP of the first multi-AP coordination procedure may be replaced with completing switching from the second primary channel to the first primary channel not later than an end moment of a second TXOP, where the second TXOP may be the TXOP of the first multi-AP coordination procedure. Specifically, the first station may complete switching before the end moment of the second TXOP, or the end moment of the second TXOP is aligned with a moment at which switching from the second primary channel to the first primary channel is completed. "Aligned" is approximate alignment. As long as a difference between the end moment of the second TXOP and the moment at which switching to the first primary channel is less than specific duration is completed, it may be considered that the two moments are aligned.

[0355] Specifically, in the implementation scenario, the first station may switch from the NPCA primary channel to the first primary channel based on the end moment of the TXOP of the first multi-AP coordination procedure. In other words, the first station may perform TXOP lengthbased NPCA. However, a difference from TXOP length-based NPCA mentioned above is that an occasion for starting to switch to the NPCA primary channel is changed. As mentioned above, FIG. 3 is used as an example. The non-AP STA 2 is triggered for NPCA by the ICF 1 or the ICR 1. For example, the non-AP STA 2 switches to the NPCA primary channel at the moment #1. In this case, the non-AP STA 2 switches to the NPCA primary channel until the entire TXOP ends. In contrast, according to the method in this implementation scenario, the non-AP STA 2 is not triggered for NPCA by the ICF 1 or the ICR 1 for. This avoids a case in which the first multi-AP coordination procedure cannot be normally performed.

[0356] (a) of FIG. 12 shows an example of the implementation scenario. As shown in (a) of FIG. 12, if a station #1 (an example of the first station) is triggered for NPCA by an ICF or ICR before a Co-BF DL PPDU and the station #1 is unrelated to current Co-BF transmission, a moment at which the station #1 starts to switch to the NPCA primary channel is after a start moment of the Co-BF DL PPDU, and the station #1 switches back to the primary channel before a TXOP of Co-BF ends.

[0357] Optionally, in another implementation scenario, when the method 1000 includes S1020a, the method 1000 further includes S1030b: The first station switches from the second primary channel to the first primary channel based on an end moment of the first PPDU.

[0358] For specific descriptions of S1030b, refer to S730. The implementation scenario may be understood as PPDU length-based NPCA. Because a length of a PPDU carrying the second frame does not meet a condition for triggering PPDU length-based NPCA, the first station is not triggered for NPCA by the second frame. This can avoid a Co-BF transmission failure. However, a length of the downlink data PPDU in the first multi-AP coordination procedure usually meets a condition of an NPCA minimum duration threshold. The first station may determine whether to perform NPCA based on a sender of the PPDU.

[0359] (b) of FIG. 12 shows an example of the implementation scenario. As shown in (b) of FIG. 12, if a station #1 (an example of the first station) detects an ICF or ICR before a Co-BF DL PPDU, PPDU length-based NPCA is enabled until a TXOP of Co-BF ends. The station #1 switches to the NPCA primary channel based on each Co-BF DL PPDU, and switches back to the primary channel before each PPDU ends.

[0360] It should be understood that effect that can be achieved in both the two implementation scenarios is as follows: If the first station is related to the first multi-AP coordination procedure, the first station does not perform NPCA, that is, always stays on the primary channel, to ensure that the first multi-AP coordination procedure is normally performed. If the first station is unrelated to the first multi-AP coordination procedure, the first station may switch to the NPCA primary channel at a start of a data PPDU in the first multi-AP coordination procedure. In addition, if the first PPDU is not transmitted due to a result of exchange of the second frame, the first station also always stays on the primary channel, thereby increasing a primary channel access opportunity.

[0361] A difference between the two implementation scenarios lies in that if the first station performs NPCA, times for switching back to the primary channel are different. The first multi-AP coordination procedure may include transmission of a plurality of downlink data PPDUs in one TXOP. In S1030a, the first station switches back to the primary channel at the end moment of the TXOP. In S1030b, the first station switches back to the primary channel at an end moment of a 1st downlink data PPDU.

[0362] In addition, if the first multi-AP coordination procedure is a Co-BF sounding procedure, the effect achieved in both the two implementation scenarios is as follows: In an entire Co-BF sounding phase, a non-AP STA is not triggered for NPCA, to ensure that Co-BF sounding can succeed. Specifically, in a first implementation scenario, because there is no downlink data PPDU, NPCA is not triggered; and in a second implementation scenario, because there is no PPDU with a sufficient length in the Co-BF sounding phase, NPCA is not triggered.

[0363] Optionally, in any one of the implementation scenarios, the first station is the first nonAP STA or the first AP. Before S1010, the method 1000 further includes: The first AP sends second indication information on the first primary channel, and correspondingly, the first non-AP STA receives the second indication information.

[0364] The second indication information indicates a type of NPCA of a non-AP STA associated with the first AP, and the non-AP STA associated with the first AP includes the first non-AP STA.

[0365] Specifically, after determining that a Co-BF or Co-SR agreement is reached with another AP (for example, the third AP), the first AP may limit NPCA of the first BSS. For example, the first AP may indicate, in at least one of a beacon frame, a probe response frame, or another management frame, that a station in the first BSS performs only PPDU length-based NPCA, and an effective time of this mode is a valid time of the Co-BF or Co-BF agreement. Alternatively, when the first AP predicts that the Co-BF procedure or the Co-BF procedure may be performed in one or more beacon intervals (beacon interval), the first AP may indicate, in at least one of a beacon frame, a probe response frame, or another management frame, that a station in the first BSS performs only PPDU length-based NPCA in these beacon intervals. Alternatively, the first AP may indicate, in a beacon interval in which the Co-BF procedure or the Co-BF procedure is expected to be performed, a station in the first BSS to enable or disable PPDU length-based NPCA.

[0366] The first AP and the third AP reach the Co-BF or Co-SR agreement. In other words, both the first AP and the third AP participate in the second multi-AP coordination procedure. The second multi-AP coordination procedure is a Co-BF procedure or a Co-BF procedure.

[0367] Optionally, in the method 1000, a solution in which the first AP sends the second indication information may also be implemented independently. Specifically, the first AP may generate the second indication information, and send the second indication information on the first primary channel, where the second indication information indicates the type of NPCA of the nonAP STA associated with the first AP. A station (for example, the first non-AP STA) receiving the second indication information may learn, based on the second indication information, of a type of NPCA that should be performed. Further, the first station may perform PPDU length-based NPCA in the method 1000, or may perform another operation related to or unrelated to NPCA.

[0368] It should be understood that, in this application, a frame (frame) is a MAC layer protocol data unit (MAC layer protocol data unit, MPDU), that is, a MAC frame, which is a concept of a MAC layer, and a PPDU is a concept of a physical layer (PHY, physical). In an actual communication process, a MAC frame is usually encapsulated in a PPDU before being sent. Unless otherwise specified in this specification, "frame exchange" may also be understood as "PPDU exchange".

[0369] The methods provided in embodiments of this application are described above with reference to FIG. 1 to FIG. 12. It may be understood that, to implement functions in the foregoing embodiments, the first station and the second station include corresponding hardware structures and / or software modules for performing the functions. A person skilled in the art should easily be aware that, in combination with units and method steps in the examples described in embodiments disclosed in this application, this application can be implemented by hardware or a combination of hardware and computer software. Whether a function is performed by hardware or hardware driven by computer software depends on particular application scenarios and design constraint conditions of the technical solutions.

[0370] FIG. 13 and FIG. 14 are diagrams of structures of communication apparatuses according to an embodiment of this application. These communication apparatuses may be configured to implement functions of the first station and second station in the foregoing method embodiments, and therefore can also achieve beneficial effect of the foregoing method embodiments. In embodiments of this application, the communication apparatus may be the first station or the second station, or may be a module (for example, a chip) used in the first station or the second station.

[0371] As shown in FIG. 13, a communication apparatus 2000 includes a transceiver unit 2020. Optionally, the communication apparatus 2000 may further include a processing unit 2010. The communication apparatus 2000 is configured to implement a function of the first station or the second station in the method embodiment shown in FIG. 7 or FIG. 10.

[0372] When the communication apparatus 2000 is configured to implement the function of the first station in the method embodiment shown in FIG. 7, the transceiver unit 2020 is configured to receive a first frame on a first primary channel. The processing unit 2010 is configured to switch from the first primary channel to a second primary channel when a first PPDU is detected in a TXOP of the first frame and the first PPDU meets a condition for triggering NPCA, where the second primary channel is an NPCA primary channel, and the first PPDU is a PPDU sent by the second station or a station associated with the second station. The processing unit 2010 is further configured to switch from the second primary channel to the first primary channel based on an end moment of the first PPDU.

[0373] When the communication apparatus 2000 is configured to implement the function of the second station in the method embodiment shown in FIG. 7, the transceiver unit 2020 is configured to send a first frame on a first primary channel, where the first frame is used to query unavailability information of a station associated with the second station, or the first frame is used to carry unavailability information of the second station.

[0374] When the communication apparatus 2000 is configured to implement the function of the first station in the method embodiment shown in FIG. 10, the transceiver unit 2020 is configured to receive a second frame on a first primary channel. The processing unit 2010 is configured to switch from the first primary channel to a second primary channel when the first station does not participate in a first multi-AP coordination procedure and it is detected that a first PPDU meets a condition for triggering NPCA, where the second primary channel is an NPCA primary channel, the first PPDU is a downlink data PPDU in the first multi-AP coordination procedure, and a BSS to which the second station belongs and a BSS to which the first station belongs are OBSSs of each other. Alternatively, the processing unit 2010 is configured to stay on the first primary channel in a TXOP of the first multi-AP coordination procedure when the first station participates in a first multi-AP coordination procedure and a second frame or a first PPDU is detected.

[0375] When the communication apparatus 2000 is configured to implement the function of the second station in the method embodiment shown in FIG. 10, the transceiver unit 2020 is configured to send a second frame on a first primary channel, where the second frame is used to transmit control information in a first multi-AP coordination procedure.

[0376] For more detailed functions of the transceiver unit 2020 and the processing unit 2010, refer to the foregoing method embodiments.

[0377] Optionally, the communication apparatus 2000 may further include a storage unit. The storage unit may be configured to store program code, program instructions, and / or data. The processing unit 2010 may read the instructions and / or the data in the storage unit, to enable the communication apparatus 2000 to implement the foregoing method embodiments.

[0378] Optionally, the transceiver unit 2020 may include a sending unit and a receiving unit. The sending unit is configured to: implement a sending operation in the foregoing method embodiments, that is, perform a sending action of the communication apparatus 2000. The receiving unit is configured to: implement a receiving operation in the foregoing method embodiments, that is, perform a receiving action of the communication apparatus 2000.

[0379] It should be noted that the communication apparatus 2000 may include the sending unit, but does not include the receiving unit, or the communication apparatus 2000 may include the receiving unit, but does not include the sending unit. Specifically, this may depend on whether the foregoing solution performed by the communication apparatus 2000 includes a sending action and a receiving action. For detailed descriptions of the functions performed by the processing unit 2010 and the transceiver unit 2020, refer to the related descriptions in the method shown in FIG. 7 or FIG. 10.

[0380] In this application, the transceiver unit may also be referred to as a transceiver module, and includes a sending module and a receiving module. The storage unit may also be referred to as a storage module.

[0381] As shown in FIG. 14, a communication apparatus 3000 includes a processor 3010 and an interface circuit 3020. The processor 3010 and the interface circuit 3020 are coupled to each other. It may be understood that the interface circuit 3020 may be a transceiver or an input / output interface. Optionally, the communication apparatus 3000 may further include a memory 3030, configured to: store instructions executed by the processor 3010, or store input data required by the processor 3010 to run the instructions, or store data generated after the processor 3010 runs the instructions. Sometimes, the interface circuit 3020 may also be understood as a part of the processor 3010. In this case, the communication apparatus 3000 includes the processor 3010.

[0382] When the communication apparatus 3000 is configured to implement the method shown in FIG. 7 or FIG. 10, the processor 3010 is configured to implement a function of the processing unit 2010, and the interface circuit 3020 is configured to implement a function of the transceiver unit 2020. For example, when the interface circuit 3020 is the transceiver, the interface circuit 3020 may include a transmitter and / or a receiver, configured to implement functions of a sending unit and a receiving unit. When the interface circuit 3020 is the input / output interface, the interface circuit 3020 may include an output interface and / or an input interface, configured to implement functions of a sending unit and a receiving unit.

[0383] When the communication apparatus 3000 is a chip, the chip includes a processor and a transceiver. The processor may be a processing module, a microprocessor, or an integrated circuit integrated on the chip. The transceiver may be an input / output circuit or a communication interface. A sending operation in the foregoing method embodiments may be understood as an output of the chip, and a receiving operation in the foregoing method embodiments may be understood as an input of the chip. Optionally, when the communication apparatus 3000 is the chip, the communication apparatus 3000 may include a memory, for example, a memory built in the chip; or the communication apparatus 3000 may not include a memory, for example, although the chip is connected to the memory, the memory and the chip are independent of each other.

[0384] In addition, when the communication apparatus is a chip used in the first station (or the second station), the chip implements the function of the first station (or the second station) in the foregoing method embodiments. That the chip receives information may be understood as: The information is first received by another module (for example, a radio frequency module or an antenna) in the first station (or the second station), and then sent to the chip by these modules. That the chip sends information may be understood as: The information is first sent to another module (for example, a radio frequency module or an antenna) in the first station (or the second station), and then sent by these modules.

[0385] It may be understood that, the processor in embodiments of this application may be a central processing unit (central processing unit, CPU), or may be another general-purpose processor, a digital signal processor (digital signal processor, DSP), an application-specific integrated circuit (application specific integrated circuit, ASIC), a field programmable gate array (field programmable gate array, FPGA) or another programmable logic device, a transistor logic device, a hardware component, or any combination thereof. The general-purpose processor may be a microprocessor or any conventional processor.

[0386] The method steps in embodiments of this application may be implemented in hardware, or may be implemented in software instructions that may be executed by the processor. The software instructions may include a corresponding software module. The software module may be stored in a random access memory, a flash memory, a read-only memory, a programmable readonly memory, an erasable programmable read-only memory, an electrically erasable programmable read-only memory, a register, a hard disk drive, a removable hard disk drive, a CD-ROM, or any other form of storage medium well-known in the art. For example, a storage medium is coupled to a processor, so that the processor can read information from the storage medium and write information into the storage medium. The storage medium may alternatively be a component of the processor. The processor and the storage medium may be disposed in an ASIC. In addition, the ASIC may be disposed in a base station or a terminal. The processor and the storage medium may alternatively exist in a base station or terminal as discrete components.

[0387] All or a part of the foregoing embodiments may be implemented by software, hardware, firmware, or any combination thereof. When the software is used for implementation, all or a part of embodiments may be implemented in a form of a computer program product. The computer program product includes one or more computer programs or instructions. When the computer programs or instructions are loaded and executed on a computer, all or a part of procedures or functions in embodiments of this application are performed. The computer may be a generalpurpose computer, a dedicated computer, a computer network, a network device, user equipment, or another programmable apparatus. The computer program or instructions may be stored in a computer-readable storage medium, or may be transmitted from a computer-readable storage medium to another computer-readable storage medium. For example, the computer program or instructions may be transmitted from a website, computer, server, or data center to another website, computer, server, or data center in a wired or wireless manner. The computer-readable storage medium may be any usable medium that can be accessed by the computer, or a data storage device, for example, a server or a data center, integrating one or more usable media. The usable medium may be a magnetic medium, for example, a floppy disk, a hard disk drive, or a magnetic tape, may be an optical medium, for example, a digital video disc, or may be a semiconductor medium, for example, a solid-state drive. The computer-readable storage medium may be a volatile or non volatile storage medium, or may include two types of storage media: a volatile storage medium and a non-volatile storage medium.

[0388] In embodiments of this application, unless otherwise stated or there is a logic conflict, terms and / or descriptions in different embodiments are consistent and may be mutually referenced, and technical features in different embodiments may be combined based on an internal logic relationship thereof, to form a new embodiment.

[0389] In this application, "at least one" means one or more, and "a plurality of" means two or more. The term "and / or" describes an association relationship between associated objects and indicates that three relationships may exist. For example, A and / or B may indicate the following cases: Only A exists, both A and B exist, and only B exists. A and B may be singular or plural. In text descriptions of this application, the character " / " usually indicates an "or" relationship between associated objects. "Including at least one of A, B, and C" may indicate: including A; including B; including C; including A and B; including A and C; including B and C; and including A, B, and C.

[0390] In this application, descriptions such as "when...", "in a case of...", and "if..." all mean that a device performs corresponding processing in a specific objective situation, and are not intended to limit a time. The device is not required to have a determining action during implementation. This does not mean that there is another limitation.

[0391] It should be understood that, in various embodiments of this application, first, second, and various numerical numbers are merely used for differentiation for ease of description, and are not intended to limit the scope of embodiments of this application. Sequence numbers of the foregoing processes do not mean an execution sequence, and the execution sequence of the processes should be determined based on functions and internal logic of the processes.

[0392] A person of ordinary skill in the art may be aware that, in combination with the examples described in embodiments disclosed in this specification, units and algorithm steps can be implemented by electronic hardware or a combination of computer software and electronic hardware. Whether the functions are performed by hardware or software depends on particular applications and design constraints of the technical solutions. A person skilled in the art may use different methods to implement the described functions for each particular application, but it should not be considered that this implementation goes beyond the scope of this application.

[0393] It may be clearly understood by a person skilled in the art that, for ease and brevity of description, for a detailed working process of the foregoing system, apparatus, and unit, refer to a corresponding process in the foregoing method embodiments. Details are not described herein again.

[0394] In the several embodiments provided in this application, it should be understood that the disclosed system, apparatus, and method may be implemented in another manner. For example, the described apparatus embodiment is merely an example. For example, division into the units is merely logic function division and may be other division during actual implementation. For example, a plurality of units or components may be combined or integrated into another system, or some features may be ignored or not performed. In addition, the displayed or discussed mutual couplings or direct couplings or communication connections may be implemented through some interfaces. The indirect couplings or communication connections between the apparatuses or units may be implemented in an electrical form, a mechanical form, or another form.

[0395] The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units may be selected based on actual requirements to achieve the objectives of the solutions in embodiments.

[0396] In addition, functional units in embodiments of this application may be integrated into one processing unit, each of the units may exist alone physically, or two or more units are integrated into one unit.

[0397] When the functions are implemented in a form of a software functional unit and sold or used as an independent product, the functions may be stored in a computer-readable storage medium. Based on such an understanding, the technical solutions of this application essentially, or the part contributing to the conventional technology, or some of the technical solutions may be implemented in a form of a software product. The software product is stored in a storage medium, and includes several instructions for instructing a computer device (which may be a personal computer, a server, or a network device) to perform all or some of the steps of the methods described in embodiments of this application. The foregoing storage medium includes any medium that can store program code, for example, a USB flash drive, a removable hard disk drive, a readonly memory (read-only memory, ROM), a random access memory (random access memory, RAM), a magnetic disk, or an optical disc.

[0398] The foregoing descriptions are merely specific implementations of this application, but are not intended to limit the protection scope of this application. Any variation or replacement readily figured out by a person skilled in the art within the technical scope disclosed in this application shall fall within the protection scope of this application. Therefore, the protection scope of this application shall be subject to the protection scope of the claims.

Claims

1. A communication method, applied to a first station, wherein the method comprises:receiving a first frame from a second station on a first primary channel, wherein the first frame is used to query unavailability information of a station associated with the second station, or the first frame is used to carry unavailability information of the second station; and a BSS to which the second station belongs and a BSS to which the first station belongs are overlapping basic service sets OBSSs of each other;switching from the first primary channel to a second primary channel when a first physical layer protocol data unit PPDU is detected in a transmission opportunity TXOP of the first frame and the first PPDU meets a condition for triggering non-primary channel access NPCA, wherein the second primary channel is an NPCA primary channel, and the first PPDU is a PPDU sent by the second station or the station associated with the second station; andswitching from the second primary channel to the first primary channel based on an end moment of the first PPDU.

2. The method according to claim 1, wherein the first frame is a first initial control frame ICF, and the first ICF meets at least one of the following conditions:the first ICF is a buffer status report poll BSRP frame, the BSRP frame comprises response type indication information, and the response type indication information indicates that a response type of a response frame of the first frame is unavailability information feedback; orthe first ICF is a BSRP frame, the BSRP frame comprises ICF type indication information, and the ICF type indication information indicates that the first ICF is used to query unavailability information; orthe first ICF is a BSRP frame, the BSRP frame comprises a guard interval and high efficiency / ultra-high reliability long training field type GI and HE / UHR-LTF type field, and a value of the GI and HE / UHR-LTF type field is 3; orthe first ICF is a BSRP frame, the BSRP frame comprises an uplink length field, and a value of the uplink length field is greater than a first threshold; orthe first ICF is a BSRP frame, the BSRP frame comprises a carrier sense CS required field, and a value of the CS required field is 1.

3. The method according to claim 1, wherein the first frame is used to carry the unavailability information of the second station, the first frame is a first initial control response ICR frame, the first ICR frame is a multi-station block acknowledgment Multi-STA BlockAck frame, and the multi-station block acknowledgment frame meets at least one of the following conditions:the multi-station block acknowledgment frame comprises the unavailability information ofthe second station; ora PPDU carrying the multi-station block acknowledgment frame is a non-high throughput non-HT PPDU; ora value of a legacy signal length L-SIG length field in a PPDU carrying the multi-station block acknowledgment frame is greater than a first threshold.

4. The method according to claim 1, wherein the first frame is a first ICF, the first ICF comprises first indication information and / or second indication information, the first indication information indicates that there is a possibility of updating the transmission opportunity TXOP of the first ICF, and the second indication information indicates that a type of NPCA performed in the TXOP of the first ICF by a station in an OBSS of the BSS to which the second station belongs is PPDU length-based NPCA.

5. The method according to claim 4, whereinthe first ICF is a BSRP frame, the first indication information is carried in a common information field or special user information field in the BSRP frame, and the second indication information is carried in the common information field or special user information field in the BSRP frame; orthe first ICF is a multi-user request to send MU-RTS frame, the first indication information is carried in a common information field or special user information field in the MU-RTS frame, and the second indication information is carried in the common information field or special user information field in the MU-RTS frame.

6. The method according to claim 1, wherein the first station is a first non-access point station non-AP STA, and before receiving the first frame, the method further comprises:receiving second indication information from a first access point AP on the first primary channel, wherein the second indication information indicates that a type of NPCA of a non-AP STA associated with the first AP is PPDU length-based NPCA, and the non-AP STA associated with the first AP comprises the first non-AP STA.

7. The method according to claim 1, wherein the first station is a first AP, and before receiving the first frame, the method further comprises:sending second indication information on the first primary channel when determining that the second station enables a dynamic unavailability operation DUO mode, wherein the second indication information indicates that a type of NPCA of a non-AP STA associated with the first AP is PPDU length-based NPCA.

8. The method according to claim 6 or 7, wherein the second indication information is carried in a beacon frame and / or a probe response frame.

9. A communication method, applied to a second station, wherein the method comprises:generating first indication information, wherein the first indication information indicates whether there is a possibility of updating a first TXOP, and the first TXOP is a TXOP of a first ICF carrying the first indication information, or a TXOP of a first PPDU carrying the first indication information; andsending the first indication information on a first primary channel.

10. The method according to claim 9, whereinthe first indication information is carried in the first ICF, the first ICF is a BSRP frame, and the first indication information is carried in a common information field or special user information field in the BSRP frame; orthe first indication information is carried in the first ICF, the first ICF is an MU-RTS frame, and the first indication information is carried in a common information field or special user information field in the MU-RTS frame; orthe first indication information is carried in a preamble of the first PPDU.

11. A communication method, applied to a first station, wherein the method comprises:receiving a second frame from a second station on a first primary channel, wherein the second frame is used to transmit control information in a first multi-AP coordination procedure, the first multi-AP coordination procedure is a coordinated spatial reuse Co-SR procedure or a coordinated beamforming Co-BF procedure, and the second station participates in the first multi-AP coordination procedure; andswitching from the first primary channel to a second primary channel when a first PPDU is detected and the first PPDU meets a condition for triggering NPCA, wherein the second primary channel is an NPCA primary channel, the first PPDU is a downlink data PPDU in the first multi-AP coordination procedure, the first station does not participate in the first multi-AP coordination procedure, and a BSS to which the second station belongs and a BSS to which the first station belongs are OBSSs of each other.

12. The method according to claim 11, wherein the method further comprises:switching from the second primary channel to the first primary channel based on an end moment of a TXOP of the first multi-AP coordination procedure; orswitching from the second primary channel to the first primary channel based on an end moment of the first PPDU.

13. The method according to claim 11 or 12, wherein the first PPDU comprises N basic service set colors BSS colors, the N BSS colors comprise a BSS color of a basic service set BSS to which a station participating in the first multi-AP coordination procedure belongs, all the N BSS colors are different from a BSS color of the BSS to which the first station belongs, and N is an integer greater than or equal to 2.

14. The method according to any one of claims 11 to 13, wherein switching from the first primary channel to the second primary channel comprises: after detecting a universal signal field U-SIG of the first PPDU, starting to switch from the first primary channel to the second primary channel.

15. The method according to any one of claims 11 to 14, wherein the first station is a first AP, and before receiving the second frame, the method further comprises:sending second indication information on the first primary channel after determining that the first AP and a third AP have reached a Co-BF or Co-SR agreement, wherein the second indication information indicates that a type of NPCA of a non-AP STA associated with the first AP is PPDU length-based NPCA, and the third AP does not participate in the first multi-AP coordination procedure.

16. The method according to any one of claims 11 to 14, wherein the first station is a first non-AP STA, and before receiving the second frame, the method further comprises:receiving second indication information from a first AP on the first primary channel, wherein the second indication information indicates that a type of NPCA of a non-AP STA associated with the first AP is PPDU length-based NPCA, and the non-AP STA associated with the first AP comprises the first non-AP STA.

17. A communication method, applied to a first station, wherein the method comprises:receiving first indication information on a first primary channel, wherein the first indication information indicates whether there is a possibility of updating a first TXOP, and the first TXOP is a TXOP of a first ICF carrying the first indication information, or a TXOP of a first PPDU carrying the first indication information; andmaking a communication decision based on the first indication information.

18. A communication method, applied to a first station, wherein the method comprises:receiving second indication information on a first primary channel, wherein the second indication information indicates that a type of NPCA of the first station is PPDU length-based NPCA;switching from the first primary channel to a second primary channel when a first PPDU is detected and the first PPDU meets a condition for triggering NPCA, wherein the second primary channel is an NPCA primary channel, the first PPDU is a PPDU sent by a second station or a station associated with a second station, and a BSS to which the second station belongs and a BSS to which the first station belongs are OBSSs of each other; andswitching from the second primary channel to the first primary channel based on an end moment of the first PPDU.

19. The method according to claim 18, wherein the first station is a first non-AP STA, andreceiving the second indication information on the first primary channel comprises:receiving the second indication information from a first AP on the first primary channel, wherein the second indication information indicates that a type of NPCA of a non-AP STA associated with the first AP is PPDU length-based NPCA, and the non-AP STA associated with the first AP comprises the first non-AP STA.

20. The method according to claim 18, wherein receiving the second indication information on the first primary channel comprises:receiving a first ICF from the second station on the first primary channel, wherein the first ICF comprises the second indication information, the second indication information indicates that a type of NPCA performed in a TXOP of the first ICF by a station in an OBSS of the BSS to which the second station belongs is PPDU length-based NPCA, the first PPDU is the PPDU sent by the second station or the station associated with the second station in the TXOP of the first ICF, and the station in the OBSS of the BSS to which the second station belongs comprises the first station.

21. The method according to claim 18, wherein receiving the second indication information on the first primary channel comprises:receiving the first PPDU on the first primary channel, wherein a preamble of the first PPDU comprises the second indication information, the second indication information indicates that a type of NPCA performed in a TXOP of the first PPDU by a station in an OBSS of the BSS to which the second station belongs is PPDU length-based NPCA, and the station in the OBSS of the BSS to which the second station belongs comprises the first station.

22. A communication method, comprising:generating second indication information, wherein the second indication information indicates that a type of NPCA of a first station is PPDU length-NPCA; andsending the second indication information on a first primary channel.

23. The method according to claim 22, wherein the method is applied to a first AP, the first station is a first non-AP STA, the second indication information indicates that a type of NPCA of a non-AP STA associated with the first AP is PPDU length-based NPCA, and the non-AP STA associated with the first AP comprises the first non-AP STA.

24. The method according to claim 23, wherein sending the second indication information on the first primary channel comprises:sending the second indication information on the first primary channel when determining that a second station enables a DUO mode, wherein a BSS to which the second station belongs and a BSS to which the first AP belongs are OBSSs of each other.

25. The method according to claim 23, wherein sending the second indication information on the first primary channel comprises:sending the second indication information on the first primary channel after determining that the first AP and a third AP have reached a Co-BF or Co-SR agreement.

26. The method according to claim 22, wherein the method is applied to a second station, and sending the second indication information on the first primary channel comprises:sending a first ICF on the first primary channel, wherein the first ICF comprises the second indication information, the second indication information indicates that a type of NPCA performed in a TXOP of the first ICF by a station in an OBSS of a BSS to which the second station belongs is PPDU length-based NPCA, and the station in the OBSS of the BSS to which the second station belongs comprises the first station.

27. The method according to claim 22, wherein the method is applied to a second station, and sending the second indication information on the first primary channel comprises:sending a first PPDU on the first primary channel, wherein a preamble of the first PPDU comprises the second indication information, the second indication information indicates that a type of NPCA performed in a TXOP of the first PPDU by a station in an OBSS of a BSS to which the second station belongs is PPDU length-based NPCA, and the station in the OBSS of the BSS to which the second station belongs comprises the first station.

28. A communication method, applied to a first station, wherein the method comprises:receiving a first frame from a second station on a first primary channel, wherein the first frame comprises an unavailability start moment, and a BSS to which the second station belongs and a BSS to which the first station belongs are OBSSs of each other; andswitching from the first primary channel to a second primary channel when a first PPDU is detected in a TXOP of the first frame and the first PPDU meets a condition for NPCA, wherein the second primary channel is an NPCA primary channel, and the first PPDU is a PPDU sent by the second station or a station associated with the second station; andswitching from the second primary channel to the first primary channel based on the unavailability start moment.

29. A communication method, applied to a first station, wherein the method comprises:receiving a first frame from a second station on a first primary channel, wherein the first frame is used to query unavailability information of a station associated with the second station, or the first frame is used to carry unavailability information of the second station; and a BSS to which the second station belongs and a BSS to which the first station belongs are OBSSs of each other; andstaying on the first primary channel in a TXOP of the first frame.

30. A communication apparatus, comprising a unit configured to perform the method according to any one of claims 1 to 29.

31. A communication apparatus, comprising:a processor, wherein the processor is coupled to a memory, the memory is configured to store a computer program, and the processor is configured to execute the computer program stored in the memory, so that the apparatus performs the method according to any one of claims 1 to 29.5        32. A computer-readable storage medium, wherein the storage medium stores a computerprogram or instructions, and when the computer program or the instructions are executed by a communication apparatus, the method according to any one of claims 1 to 29 is implemented.

33. A computer program product, comprising a computer program, wherein when the computer program runs, the method according to any one of claims 1 to 29 is implemented.10

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