Communication method and communication devices

Abstract

Provided are a communication method and communication devices. The communication method comprises: in response to a first STA in a first BSS receiving a first PPDU, the first STA switching from a primary channel of the first BSS to a non-primary channel, wherein the first PPDU is a PPDU transmitted by a second BSS; and after switching to the non-primary channel, the first STA switching from the non-primary channel back to the primary channel according to a first rule.

Description

Communication methods and communication equipment Technical Field

[0001] This application relates to the field of communication technology, and more specifically, to a communication method and a communication device. Background Technology

[0002] When the primary channel of a station (STA) in a basic service set (BSS) is occupied by transmissions from overlapping BSSs (OBSSs), the STA can switch from the primary channel to a non-primary channel to continue transmission.

[0003] However, there are currently no clear regulations on how the STA switches back from a non-primary channel to the primary channel. Summary of the Invention

[0004] This application provides a communication method and a communication device. The various aspects covered by this application are described below.

[0005] In a first aspect, a communication method is provided, comprising: in response to a first STA of a first BSS receiving a first physical layer protocol data unit (PPDU), the first STA switches from the primary channel of the first BSS to a non-primary channel, wherein the first PPDU is a PPDU transmitted by a second BSS; after switching to the non-primary channel, the first STA switches back to the primary channel from the non-primary channel according to a first rule.

[0006] In a second aspect, a communication device is provided, the communication device being a first STA, the first STA comprising: a processing module, configured to, in response to the first STA of a first BSS receiving a first PPDU, switch from the primary channel of the first BSS to a non-primary channel, the first PPDU being a PPDU transmitted by a second BSS; and, after switching to the non-primary channel, switch back to the primary channel according to a first rule.

[0007] Thirdly, a communication device is provided, including a transceiver, a memory, and a processor, wherein the memory is used to store one or more computer programs, and the processor is used to invoke the computer programs in the memory to cause the communication device to perform the method described in the first aspect.

[0008] Fourthly, a computer-readable storage medium is provided, the computer-readable storage medium storing a computer program that causes a communication device to perform the method described in the first aspect.

[0009] Fifthly, a computer program product is provided, the computer program product including a non-transitory computer-readable storage medium storing a computer program operable to cause a communication device to perform the method described in the first aspect.

[0010] In a sixth aspect, a chip is provided, which includes a memory and a processor, the processor being able to call and run a computer program from the memory to implement the method described in the first aspect above.

[0011] By clearly defining the rules for the first STA to switch back to the primary channel from the non-primary channel, communication reliability can be improved. Attached Figure Description

[0012] Figure 1 is a schematic diagram of a wireless communication system applicable to embodiments of this application.

[0013] Figure 2 is an example diagram of the process of STA switching from the primary channel to a non-primary channel.

[0014] Figure 3 is a schematic flowchart of the communication method provided in an embodiment of this application.

[0015] Figure 4 is an example diagram of the communication process provided in an embodiment of this application.

[0016] Figure 5 is another example diagram of the communication process provided in the embodiments of this application.

[0017] Figure 6 is a schematic structural diagram of the communication device provided in an embodiment of this application.

[0018] Figure 7 is a schematic structural diagram of the communication device provided in an embodiment of this application. Detailed Implementation

[0019] The technical solutions in this application will now be described with reference to the accompanying drawings.

[0020] Communication system

[0021] The technical solutions of this application can be applied to various communication systems, such as wireless local area networks (WLANs), wireless fidelity (WIFI), high-performance radio local area networks (HIPELANs), wide area networks (WANs), cellular networks, or other communication systems. For example, the technical solutions provided in this application can be applied to communication systems using the 802.11 standard. Exemplarily, the 802.11 standard includes, but is not limited to, the 802.11ax standard, the 802.11be standard, the 802.11bn standard, and the next-generation 802.11 standard (post802.11bn).

[0022] Figure 1 shows a schematic diagram of a communication system applicable to embodiments of this application. Referring to Figure 1, the communication devices in the communication system 100 may include access point (AP) 111, AP 112, and station (STA) 121 and STA 122, wherein STA 121 can access the network through AP 111, and STA 122 can access the network through AP 112.

[0023] In some implementations, a STA can establish an association with one or more APs, after which the associated STAs and APs can communicate with each other. Referring to Figure 1, AP 111 and STA 121 can communicate after establishing an association, and AP 112 and STA 122 can communicate after establishing an association.

[0024] In some implementations, the communication in the communication system 100 can be communication between the AP and the Non-AP STA, or communication between the Non-AP STA and the Non-AP STA, or communication between the STA and the peer STA. The peer STA can refer to the device that communicates with the STA. For example, the peer STA may be an AP or a Non-AP STA.

[0025] It should be understood that Figure 1 exemplarily shows two AP STAs and two Non-AP STAs. The communication system 100 may also include more AP STAs, or the communication system 100 may include other numbers of Non-AP STAs. This application embodiment does not limit this.

[0026] In addition, the above-mentioned communication system can be applied to scenarios involving multi-device collaboration, such as multi-AP (multi-access points) collaboration or multi-site collaboration.

[0027] In the embodiments of this application, the names of AP and / or STA are not limited. In some scenarios, AP can also be called AP STA, that is, in a sense, AP is also a type of STA. In other scenarios, STA can be called non-AP STA.

[0028] In some scenarios, the aforementioned communication equipment can also be a "multi-link device (MLD)," meaning a device that can communicate through multiple communication links. These multiple communication links can include communication links in different frequency bands, such as millimeter-wave bands and / or low-frequency bands. Typically, if the multi-link device is an access point (AP), then the AP can also be called an "AP MLD." If the multi-link device is a non-AP STA, then the non-AP STA can also be called a "Non-AP MLD."

[0029] In this application embodiment, the AP can be a device in a wireless network. The AP can be a communication server, router, switch, bridge, or other communication entity. Alternatively, the AP can include various forms of macro base stations, micro base stations, relay stations, etc. Of course, the AP can also be a chip, circuit, or processing system within these various forms of devices, thereby implementing the methods and functions of this application embodiment. APs can be applied in various scenarios, such as sensor nodes in smart cities (e.g., smart water meters, smart electricity meters, smart air quality monitoring nodes), smart devices in smart homes (e.g., smart cameras, projectors, displays, televisions, audio equipment, refrigerators, washing machines, etc.), nodes in the Internet of Things (IoT), entertainment terminals (e.g., AR, VR, and other wearable devices), smart devices in smart offices (e.g., printers, projectors, etc.), vehicle-to-everything (V2X) devices, and some infrastructure in daily life scenarios (e.g., vending machines, supermarket self-service navigation kiosks, self-service checkout machines, self-service ordering machines, etc.).

[0030] In some implementations, the role of the STA in the communication system is not absolute; in some scenarios, the STA can act as an AP. For example, in a scenario where a mobile phone connects to a router, the mobile phone can be a Non-AP STA, while when the mobile phone acts as a hotspot for other mobile phones, it acts as an AP.

[0031] In the embodiments of this application, the STA can be a device with wireless transceiver capabilities, such as one that supports the 802.11 series of protocols and can communicate with the AP or other STAs. For example, an STA is any user communication device that allows users to communicate with the AP and thus with the WLAN. STAs include, for example, user equipment (UE), mobile station (MS), mobile terminal (MT), access terminal, user unit, user station, mobile station, mobile station, remote station, remote terminal, mobile device, user terminal, terminal, wireless communication equipment, user agent, or user device, etc.

[0032] In this application embodiment, the STA can also be a device that provides voice / data / image connectivity to the user, such as a handheld device, vehicle device, home device, home appliance, gaming device, etc., with wireless connection function or equipped with a wireless communication module. Examples include: mobile phones, tablets, laptops, PDAs, mobile internet devices (MIDs), wearable devices, virtual reality (VR) devices, augmented reality (AR) devices, wireless terminals in industrial control, wireless terminals in self-driving vehicles, drones or aerial photography equipment, wireless terminals in remote medical surgery, wireless terminals in smart grids, wireless terminals in transportation safety, wireless terminals in smart cities, wireless terminals in smart homes, cellular phones, cordless phones, session initiation protocol (SIP) phones, wireless local loop (WLL) stations, personal digital assistants (PDAs), handheld devices with wireless communication capabilities, computing devices or other processing devices connected to a wireless modem, in-vehicle devices, wearable devices, terminal devices in 5G networks, or future evolution of public land mobile communication networks. Terminal devices in a network (PLMN) can also be televisions, refrigerators, washing machines, kitchen appliances, door locks, fish tanks, robot vacuum cleaners, game consoles, cameras / camcorders, etc. with wireless connectivity, but this application embodiment is not limited to these.

[0033] By way of example and not limitation, in this embodiment, the STA can also be a wearable device. Wearable devices, also known as wearable smart devices, are a general term for devices that utilize wearable technology to intelligently design and develop everyday wearables, such as glasses, gloves, watches, clothing, and shoes. Examples include smartwatches or smart glasses, as well as devices that focus on a specific type of application function and require cooperation with other devices such as smartphones, such as various smart bracelets and smart jewelry for vital sign monitoring.

[0034] Furthermore, in this embodiment, the STA can also be a terminal device in an Internet of Things (IoT) system. IoT is an important component of future information technology development, and its main technical feature is connecting objects to networks through communication technologies, thereby realizing an intelligent network for human-machine interconnection and object-to-object interconnection. In this embodiment, IoT technology can achieve massive connectivity, deep coverage, and low terminal power consumption through technologies such as narrowband (NB).

[0035] Furthermore, in this embodiment, the STA can be a device in a vehicle-to-everything (V2X) system. The communication methods in a V2X system are collectively referred to as V2X (where X represents anything). For example, V2X communication includes: vehicle-to-vehicle (V2V) communication, vehicle-to-infrastructure (V2I) communication, vehicle-to-pedestrian (V2P) communication, or vehicle-to-network (V2N) communication, etc.

[0036] In addition, in the embodiments of this application, the STA may also include sensors such as smart printers, train detectors, and gas stations. Its main functions include collecting data (some terminal devices), receiving control information and downlink data from the AP, and sending electromagnetic waves to transmit data to the AP.

[0037] In addition, the AP in this application embodiment can be a device for communicating with the STA. The AP can be a network device in a wireless local area network, and the AP can be used to communicate with the STA through the wireless local area network.

[0038] From the perspective of the communication standards supported by the AP, in some implementations, the AP can be a device that supports the 802.11be standard. The AP can also be a device that supports various current and future 802.11 family WLAN standards such as 802.11ax, 802.11ac, 802.11n, 802.11g, 802.11b, and 802.11a.

[0039] From the perspective of the communication standards supported by the STA, in some implementations, Non-AP STAs can support the 802.11be standard. Non-AP STAs can also support various current and future 802.11 family of wireless local area networks (WLAN) standards, such as 802.11ax, 802.11ac, 802.11n, 802.11g, 802.11b, and 802.11a.

[0040] In this application embodiment, the frequency bands supported by WLAN technology are not limited. In some implementations, the frequency bands supported by WLAN technology may include, but are not limited to: low frequency bands (e.g., 2.4GHz, 5GHz, 6GHz) and high frequency bands (e.g., 45GHz, 60GHz).

[0041] It should be understood that the specific forms of STA and AP are not specifically limited in the embodiments of this application, and are merely illustrative examples.

[0042] First, let's introduce some channel-related concepts:

[0043] Primary Channel: This refers to the channel shared by all member stations in the basic service set (BSS). For example, in a BSS corresponding to 20MHz, 40MHz, 80MHz, 160MHz, or 80+80MHz, the primary channel is a main 20MHz channel.

[0044] Nonprimary channel: refers to any 20MHz channel other than the primary 20MHz channel within a 40MHz, 80MHz, 160MHz, or 80+80MHz basic service set (BSS).

[0045] Primary 20MHz Channel: This refers to the 20MHz channel used to transmit 20MHz physical layer (PHY) protocol data units (PPDUs) within a basic service set (BSS) of 20MHz, 40MHz, 80MHz, 160MHz, or 80+80MHz.

[0046] The primary 40MHz channel is a 40MHz channel used to transmit 40MHz physical layer (PHY) protocol data units (PPDUs) within an 80MHz, 160MHz, or 80+80MHz basic service set (BSS).

[0047] Primary 80MHz Channel: Within a 160MHz or 80+80MHz basic service set (BSS), this 80MHz channel is used to transmit 80MHz physical layer (PHY) protocol data units (PPDUs).

[0048] Primary 160MHz Channel: Within a 320MHz basic service set (BSS), this is the 160MHz channel that includes the primary 20MHz channel.

[0049] Sometimes the aforementioned main 20MHz channel, main 40MHz channel, main 80MHz channel, and main 160MHz channel are collectively referred to as the main channel.

[0050] A secondary channel is a channel associated with a primary channel and used to create a channel wider than the primary channel. In a 40MHz, 80MHz, 160MHz, or 80+80MHz basic service set (BSS), the secondary channel is a secondary 20MHz channel.

[0051] Secondary 20MHz Channel: In the 40MHz very high throughput basic service set, the 20MHz channel adjacent to the primary 20MHz channel together forms the 40MHz channel corresponding to the 40MHz very high throughput basic service set. In the 80MHz very high throughput basic service set, the 20MHz channel adjacent to the primary 20MHz channel together forms the primary 40MHz channel corresponding to the 80MHz very high throughput basic service set. In the 160MHz or 80+80MHz very high throughput basic service set, the 20MHz channel adjacent to the primary 20MHz channel together forms the primary 40MHz channel corresponding to the 160MHz or 80+80MHz very high throughput basic service set. (In a 40MHz very high throughput(VHT)basic service set(BSS), the 20MHz channel adjacent to the primary 20MHz channel that together form the 40MHz channel of the 40MHz VHT BSS.In an 80MHz VHT BSS, the 20MHz channel adjacent to the primary 20MHz channel that together form the primary 40MHz channel of the 80MHz VHT BSS.In a 160MHz or 80+80MHz VHT BSS, the 20MHz channel adjacent to the primary 20MHz channel that together form the primary 40MHz channel of the 160MHz or 80+80MHz VHT BSS.In a VHT BSS, the secondary 20MHz channel is also the secondary channel.)

[0052] The secondary 40MHz channel: In an 80MHz very high throughput (VHT) basic service set (BSS), the 40MHz channel adjacent to the primary 40MHz channel together forms the 80MHz channel of the 80MHz VHT BSS. In a 160MHz or 80+80MHz VHT BSS, the 40MHz channel adjacent to the primary 40MHz channel together forms the primary 80MHz channel.

[0053] Secondary 80MHz Channel: In a 160MHz or 80+80MHz very high throughput (VHT) basic service set (BSS), the 80MHz channel, excluding the primary 20MHz channel, together with the primary 80MHz channel, forms the 160MHz or 80+80MHz channel corresponding to the 160MHz or 80+80MHz VHT BSS.

[0054] The Secondary 160MHz Channel: Within a 320MHz basic service set (BSS), the 160MHz channel, excluding the primary 20MHz channel, together with the primary 160MHz channel, forms the 320MHz channel corresponding to the 320MHz extremely high throughput (EHT) BSS.

[0055] Sometimes the aforementioned 20MHz, 40MHz, 80MHz, and 160MHz channels are collectively referred to as secondary channels.

[0056] Operating Channel: This refers to the channel used to transmit beacon frames. It can be a collection of multiple channels used during operation. Specific examples include 20MHz, 40MHz, 80MHz, 160MHz, or 320MHz operating channels.

[0057] Operating Channel Width: This refers to the bandwidth of the channel through which the station (STA) is currently able to receive signals. Examples include 20MHz, 40MHz, 80MHz, 160MHz, or 320MHz.

[0058] Anchor Channel: Also known as Non-Primary Channel Access (NPCA) Primary Channel, Second Primary Channel, Temporary Primary Channel, Assistant Primary Channel, Auxiliary Primary Channel, or Target Subchannel. A subchannel within the current operating channel of the basic service set, used as the primary channel when the access point and associated site perform non-primary channel access. Specifically, assuming the access point's current operating channel bandwidth is 160MHz, the subchannels include: Primary 80MHz (P80, including Primary 20MHz (P20), Secondary 20MHz (S20), Secondary 40MHz (S40, including S20-1, S20-2)), and Secondary 80MHz (S80, including S20-3, S20-4, S20-5, S20-6). For example, when access points and associated sites perform non-primary channel access, they use S20-3 as P20, S20-4 as S20, S20-5 and S20-6 as S40, and P80 as S80.

[0059] Non-primary channel access (NPCA)

[0060] When the primary channel is detected to be busy, both the AP and non-AP STA can switch to a non-primary channel for transmission (see reference: 11-23-1891-00-00bn-nonprimary-channel-access-follow-up).

[0061] After the AP switches to a non-primary channel, it can query the non-AP STA for availability through multi-user request-to-send (MU-RTS) and clear to send (CTS) frame interactions.

[0062] The relevant technologies define the conditions for APs and STAs to switch to non-primary channels to access the primary channel (NPCA primary channel), and define the channel access rules and transmission rules for NPCA APs and NPCA STAs on the NPCA primary channel.

[0063] Transmission failure.

[0064] The proposed technology states that if a STA does not receive a corresponding CTS frame within the CTSTimeout period after sending an RTS frame, the RTS frame transmission is considered to have failed, and a backoff procedure must be initiated. See the description below for details.

[0065] After transmitting an RTS frame,the STA shall wait for a CTSTimeout interval with a value of aSIFSTime+aSlotTime+aRxPHYStartDelay.This interval begins when the MAC receives a PHY-TXEND.confirm primitive.If a PHY-RXEARLYSIG.indication or PHY-RXSTART.indication primitive does not occur during the CTSTimeout interval,the STA shall conclude that the transmission of the RTS frame has failed,and this STA shall invoke its backoff procedure upon expiration of the CTSTimeout interval.If aPHYRXEARLYSIG.indication or PHY-RXSTART.indication primitive does occur during the CTSTimeout interval,the STA shall wait for the corresponding PHY-RXEND.indication primitive to determine whether the RTS frame transmission was successful.The reception of a CTS frame addressed to the STA,corresponding to this PHY-RXEND.indication primitive,shall be interpreted as successful response,permitting the frame exchange sequence to continue.Anything else, including the reception of any other frame, shall be interpreted as failure of the RTS frame transmission. In this instance, the STA shall invoke its backoff procedure at the PHY-RXEND.indication primitive and may process the received frame.

[0066] The relevant technology proposes that if the STA does not receive a corresponding signal within the AckTimeout period after sending a Media Access Control Protocol Data Unit (MPDU) that requires an Ack or BlockAck frame response, the MPDU transmission is considered to have failed, and a backoff procedure must be initiated. See the description below for details.

[0067] After transmitting an MPDU that requires an Ack or BlockAck frame as a response, the STA shall wait for an AckTimeout interval,with a value of aSIFSTime+aSlotTime+aRxPHYStartDelay,starting at the PHYTXEND.confirm primitive.If a PHY-RXEARLYSIG.indication or PHY-RXSTART.indication primitive does not occur during the AckTimeout interval,the STA concludes that the transmission of the MPDU has failed, and this STA shall invoke its backoff procedure upon expiration of the AckTimeout interval.

[0068] The relevant technical definition for successful or failed MPDU transmission is as follows: After sending an MPDU that requires an immediate response, the STA needs to wait for a timeout period. If no response is received within this timeout period, the MPDU transmission is lost. See the description below for details.

[0069] For the purposes of this subclause, transmission success or failure of an MPDU is defined as follows:

[0070] After transmitting an MPDU(even if it is carried in an A-MPDU,as part of a VHT or S1G MU PPDU,or as part of an HE MU PPDU that is sent using TXVECTOR parameter NUM_USERS>1)that requires an immediate response:

[0071] The STA shall wait for a timeout interval of duration aSIFSTime+aSlotTime+aRxPHYStartDelay,starting when the MAC receives a PHY-TXEND.confirm primitive.If a PHY-RXEARLYSIG.indication or PHY-RXSTART.indication primitive does not occur during the timeout interval, the transmission of the MPDU has failed.

[0072] If a PHY-RXEARLYSIG.indication or PHY-RXSTART.indication primitive does occur during the timeout interval, the STA shall wait for the corresponding PHY-RXEND.indication primitive to receive a response MPDU that either does not have a TA field or is sent by the recipient of the MPDU requiring a response. Anything else, including the reception of any other frame, is defined to be a failure.

[0073] The nonfinal(re)transmission of an MPDU that is delivered using the GCR unsolicited retry retransmission policy is defined to be a failure.

[0074] In all other cases, the transmission of the MPDU is considered to be a successful transmission.

[0075] Furthermore, related technologies propose that the enhanced distributed channel access function (EDCAF) must initiate a backoff procedure when any of the following events occur: The MPDU carried in the initial PPDU sent by the transmission opportunity (TXOP) owner fails to transmit, and this initial PPDU does not request a high-efficiency (HE) trigger-based (TB) PPDU; or all MPDUs carried in the initial PPDU sent by the TXOP owner fail to transmit, and this initial PPDU includes an MPDU requesting an HE TB PPDU. Details are as follows.

[0076] The backoff procedure shall be invoked by an EDCAF if any of the following events occurs:

[0077] c)For the EDCAF that is the TXOP holder,the transmission of an MPDU in the initial PPDU of a TXOP fails,as defined in this subclause,and the initial PPDU does not solicit an HE TB PPDU.

[0078] f)The transmission of all MPDUs in the initial PPDU of a TXOP fails,as defined in this subclause,and the PPDU contains an MPDU that solicits an HE TB PPDU.

[0079] If the backoff procedure is invoked for reason c),d),f),i),or j)above,CW[AC]and QSRC[AC]shall be updated as follows:

[0080] If QSRC[AC]is less than dot11ShortRetryLimit,

[0081] QSRC[AC]shall be incremented by 1.

[0082] CW[AC]shall be set to the lesser of CWmax[AC]and 2QSRC[AC]×(CWmin[AC]+1)–1.

[0083] Else

[0084] QSRC[AC]shall be set to 0.

[0085] CW[AC] shall be set to CWmin[AC].

[0086] Media access recovery process

[0087] Related technologies propose that when the STA loses media synchronization for more than aMediumSyncThreshold (72 microseconds), a MediumSyncDelay timer must be started to restore media access. When the STA receives an MPDU or a PPDU with a valid TXOP_DURATION value, the STA resets this timer to 0. When the timer is non-zero, if the STA can acquire a TXOP using dot11MSDOFDMEDthreshold, the STA must send an RTS as the initial frame for the TXOP, and the total number of attempts to initiate a TXOP after the timer starts must not exceed dot11MSDTXOPMax. The default value of dot11MSDOFDMEDthreshold is –72dBm. The default value of dot11MSDTXOPMax is 1. Details are as follows.

[0088] A non-AP STA affiliated with a non-AP MLD or an AP affiliated with an NSTR mobile AP MLD that operates on an NSTR link pair is considered to have lost medium synchronization when the other STA, which is affiliated with the same MLD and operates on that link pair,transmits a PPDU,except when both STAs ended a transmission at the same time.

[0089] A STA that has lost medium synchronization as described above shall start a MediumSyncDelay timer and begin counting down from the end of that transmission if that transmission duration is greater than aMediumSyncThreshold unless its previous MediumSyncDelay timer has not expired.The STA may choose not to(re)start the MediumSyncDelay timer if the transmission duration is less than or equal to aMediumSyncThreshold.The aMediumSyncThreshold is set to 72μs.

[0090] NOTE 1—The value of 72μs is chosen to cover at least the PPDU lengths of RTS / CTS / Ack frames using non-HT or non-HT duplicate PPDU format with 6Mb / s data rate,as well as the PPDU lengths of most typical BlockAck frames.

[0091] The MediumSyncDelay timer is a single timer,shared by all EDCAFs within a STA,whose value is set to dot11MSDTimerDuration.The STA initializes dot11MSDTimerDuration to aPPDUMaxTime defined in Table36-70(EHT PHY characteristics).A non-AP STA shall update dot11MSDTimerDuration with the value contained in the Medium Synchronization Delay Information field,if present,of the Basic Multi-Link element in the most recent frame received from its associated AP.In addition,the timer resets to zero when any of the following events occur:

[0092] —The STA receives an MPDU.

[0093] —The STA receives a PPDU for which the RXVECTOR parameter TXOP_DURATION is not UNSPECIFIED.

[0094] A STA that is capable of obtaining a TXOP while the MediumSyncDelay timer has a nonzero value shall use dot11MSDOFDMEDthreshold instead of dot11OFDMEDThreshold as specified in 36.3.21.6.3(CCA sensitivity for the primary 20MHz channel)in order to detect a channel busy condition in the primary 20MHz channel if the MediumSyncDelay timer has a nonzero value.

[0095] If a STA is capable of obtaining a TXOP while the MediumSyncDelay timer has a nonzero value,it shall perform the following when the timer has a nonzero value:

[0096] —If it is a non-AP STA,it shall transmit an RTS frame to its associated AP as the initial frame in an obtained TXOP.

[0097] —If it is an AP affiliated with an NSTR mobile AP MLD,then the AP shall transmit an RTS frame to an associated non-AP STA as the initial frame in an obtained TXOP and follow the rules defined in 35.3.19(NSTR mobile AP MLD operation).

[0098] —Shall not attempt to initiate a TXOP more than dot11MSDTXOPMax times since the start of the timer.

[0099] Otherwise,it shall perform CCA until the MediumSyncDelay timer has expired before it initiates atransmission.

[0100] A STA that has a nonzero MediumSyncDelay timer shall not transmit any PPDU using OBSS PD-based spatial reuse operation.

[0101] An AP affiliated with an AP MLD may include the Medium Synchronization Delay Information subfield in the Common Info field of the Basic Multi-Link element carried in transmitted(Re)Association Response frame or multi-link probe response to provide medium synchronization information used by the AP MLD.

[0102] The default value of dot11MSDOFDMEDthreshold is–72dBm and the default value of dot11MSDTXOPMax is 1,respectively.Each non-AP STA affiliated with a non-AP MLD shall set dot11MSDTXOPMax and dot11MSDOFDMEDthreshold to the most recent values carried in the Medium Synchronization Maximum Number Of TXOPs subfield and Medium Synchronization OFDM ED Threshold subfield,respectively,if they are present in the Common Info field of the Basic Multi-Link element received by any non-AP STA affiliated with the same non-AP MLD from its associated AP affiliated with the AP MLD with which the non-AP MLD has performed ML setup.

[0103] NOTE—If either the intra-BSS NAV or the basic NAV is nonzero in the non-AP STA affiliated with the non-AP MLD when it starts the MediumSyncDelay timer,the non-AP STA does not initiate any TXOP and follows the same rules as an HE STA to respond to any RTS or MU-RTS frame until both NAVs expire.

[0104] During the aCCAtime immediately following the end of the transmission that caused loss of medium synchronization and subsequent initiation of the MediumSyncDelay timer at the non-AP STA, if the received signal strength exceeds the–62dBm threshold for the primary 20MHz channel and no start of a PPDU is detected, the STA should defer for EIFS beginning when the received signal strength falls below the threshold.

[0105] As described in the previous introduction to NPCA technology, when the primary channel of a STA in a BSS is occupied by the transmission of an OBSS, the STA can switch from the primary channel to a non-primary channel to continue transmission.

[0106] However, there are currently no clear regulations on how the STA switches back from a non-primary channel to the primary channel.

[0107] The embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0108] Figure 3 is a schematic flowchart of the communication method provided in an embodiment of this application. The method shown in Figure 3 is described from the perspective of a first STA. The first STA mentioned here can be a non-AP STA, AP, non-AP MLD, or AP MLD.

[0109] The first STA can be a STA of the first BSS, meaning it can be an AP of the first BSS or a STA associated with an AP of the first BSS. The first BSS and the second BSS are spatially adjacent BSSs. For example, the first BSS and the second BSS might be two adjacent BSSs located in a relatively densely deployed Wi-Fi network environment, and the first BSS and the second BSS satisfy one or more of the following: partial or complete overlap of subchannels between the first BSS and the second BSS; partial or complete overlap of the basic service area (BSA) between the first BSS and the second BSS. The first BSS and the second BSS can be each other's OBSS. During the operation of the first BSS and the second BSS, if, for a period of time, one of the subchannels occupied by the second BSS's transmission, such as a 20MHz subchannel, is the primary channel of the first BSS, such as the primary 20MHz channel, then the first BSS may be unable to transmit on the primary channel due to primary channel congestion, or in other words, the primary channel medium is busy. To improve spectrum efficiency, the first station within the first BSS, which can be an AP or non-AP STA of the first BSS, can switch to a non-primary channel of the first BSS for transmission when the primary channel is detected to be busy.

[0110] In some implementations, the operation of the first STA switching from the primary channel to a non-primary channel for channel access and communication can be called an NPCA operation. Correspondingly, the non-primary channel mentioned above can be called the NPCA primary channel. Without conflict, the non-primary channel and NPCA primary channel mentioned in the various embodiments of this application can be used interchangeably.

[0111] The first STA can determine whether the primary channel is occupied by the second BSS by detecting PPDUs. For example, if the first STA detects a first PPDU, or if the detection of the first PPDU triggers the corresponding internal primitive PHY-RXSTART.indication primitive, and the first PPDU comes from the second BSS, or in other words, the first PPDU is an inter-BSS PPDU, then as shown in step S310 of Figure 3, in response to receiving the first PPDU, the first STA switches from the primary channel of the first BSS to a non-primary channel.

[0112] In some implementations, the first PPDU can be a high-efficiency (HE) PPDU, an extremely high-throughput (EHT) PPDU, or an ultra-high-reliability (UHR) PPDU. Alternatively, the first PPDU can be a PPDU containing a control frame, such as an initial control frame, or a response frame to a control frame, or an initial response frame.

[0113] In some implementations, after the first STA detects the first PPDU, it can further determine whether the first PPDU meets certain conditions. If the first PPDU meets certain conditions, it can then switch from the primary channel of the first BSS to a non-primary channel.

[0114] Taking a first PPDU as an HE PPDU, EHT PPDU, or UHR PPDU as an example, the first STA can switch from the primary channel to a non-primary channel or the NPCA primary channel when some or all of the following conditions are met: the first PPDU is a PPDU of the second BSS or an inter-BSS PPDU; the duration or remaining duration of the first PPDU is greater than the first value corresponding to the first BSS; and the channel occupied by the first PPDU does not overlap with the non-primary channel or the NPCA primary channel. The remaining duration of the first PPDU mentioned in the various embodiments of this application refers to the remaining duration of the first PPDU's transmission duration from the third moment, where the third moment is the moment when the primary channel begins to switch to the non-primary channel. A detailed description of the third moment is provided below. The first value is the value indicated by the NPCA minimum duration threshold field in the most recently received or transmitted relevant frame.

[0115] Taking a PPDU containing a control frame, such as an initial control frame or a response frame of a control frame, as an example, the first STA can switch from the primary channel to a non-primary channel or the NPCA primary channel when some or all of the following conditions are met: the first PPDU is a PPDU of the second BSS or an inter-BSS PPDU; the TXOP duration determined by the duration field in the control or response frame of the first PPDU is greater than the first value corresponding to the first BSS; and the channel occupied by the first PPDU does not overlap with the non-primary channel or the NPCA primary channel. The first value is the value indicated by the NPCA minimum duration threshold field in the most recently received or transmitted relevant frame.

[0116] As a more concrete example, the first STA can determine whether to switch from the primary channel to a non-primary channel or the NPCA primary channel according to the following rules:

[0117] a)the STA received a PPDU and / or received a PHY-RXSTART.indication primitive for an HE / EHT / UHR PPDU on the BSS primary channel and all of the following conditions are true:

[0118] a.the PPDU is classified by the STA as an inter-BSS PPDU following the procedure defined in 26.2.2(Intra-BSS and inter-BSS PPDU classification).

[0119] b.the duration of the PPDU or the remaining duration of the PPDU is greater than the value indicated in the most recently received or transmitted NPCA Minimum Duration Threshold field corresponding to its BSS.

[0120] c.the 20 / 40 / 80 / 160MHz channel occupied by the PPDU is identified by the STA,based on the Bandwidth field in the PHY preamble of the PPDU and the channel allocations in the corresponding band,and the channel occupied by the PPDU does not overlap with the NPCA primary channel.

[0121] b)the STA received a PPDU containing a Control frame and / or a PPDU containing an initial response frame of a Control frame exchange on the BSS primary channel and all of the following conditions apply:

[0122] a.the received PPDU(s)are classified by the STA as inter-BSS PPDU(s)following the procedure defined in 26.2.2(Intra-BSS and inter-BSS PPDU classification).

[0123] b.the TXOP duration,determined from the Duration field of the received frame(s),is greater than the value indicated in the most recently received or transmitted NPCA Minimum Duration Threshold field corresponding to its BSS.

[0124] c.the 20 / 40 / 80 / 160MHz channel occupied by the received PPDU(s) is identified by the STA,based on the channel allocations in the corresponding band and the PPDU bandwidth that is signaled in the received PPDU(s)or obtained from the RXVECTOR parameter CH_BANDWIDTH_IN_NON_HT of the received PPDU(s)and the channel occupied by the received PPDU(s),does not overlap with the NPCA primary channel.

[0125] i.if the Control frame is an RTS frame in a non-HT(duplicate)PPDU, then it includes a bandwidth signaling TA and the signaled PPDU bandwidth is 20MHz,40MHz,80MHz,or 160MHz.

[0126] ii.identification of the channel occupied by a received CTS frame in a non-HT(duplicate)PPDU is determined by examining the RTS frame or the MU-RTS frame that elicited the CTS response.

[0127] The moment when the first STA switches from the primary channel to a non-primary channel can be called the NPCA handover moment or the third moment. The definition of the NPCA handover moment can be related to the type of the first PPDU.

[0128] For example, if the first PPDU is an HE PPDU, EHT PPDU, or UHR PPDU, the NPCA switch time can be represented as the NPCA HE switch time, which can be defined as the time when the first STA successfully decodes the first SIG field in the first PPDU. The first SIG field mentioned here can be, for example, the HE-SIG-A field or the U-SIG field (where NPCA HE switch time is defined as the time the STA successfully decodes the HE-SIG-A field or the U-SIG field of the inter-BSS PPDU).

[0129] For example, if the first PPDU is a PPDU containing a control frame, such as an initial control frame or a response frame of a control frame, then the NPCA switching time can be represented by the NPCA NHT switch time, which can be defined as the time when the first STA receives the response frame of the control frame (where NPCA NHT switch time is defined as the time the STA receives the corresponding inter-BSS control response frame).

[0130] In some implementations, when the first STA switches from the primary channel to a non-primary channel, the switch needs to be completed within a certain switching delay starting from the NPCA switching time. This switching delay will be referred to as the NPCA switching delay of the first STA.

[0131] As a more concrete example, the first STA can follow these rules when switching from the primary channel to a non-primary channel:

[0132] a)If the STA switches from the BSS primary channel to the NPCA primary channel based on an inter-BSS HE / EHT / UHR PPDU reception on the BSS primary channel,the STA shall initiate the switch at the NPCA HE switch time and it shall be ready to transmit and receive frames(subject to its capabilities and operating mode)on the NPCA primary channel no later than the value of its most recently indicated NPCA switching delay after the NPCA HE switch time.

[0133] b)If the STA switches from the BSS primary channel to the NPCA primary channel based on an inter-BSS Control frame exchange reception on the primary channel,the STA shall initiate the switch at the NPCA NHT switch time and it shall be ready to transmit and receive frames addressed to it(subject to its capabilities and operating mode)on the NPCA primary channel no later than the value of its most recently indicated NPCA switching delay after the NPCA NHT switch time.

[0134] c)The STA shall use the same EDCA parameter set,MU EDCA parameter set,and EPCS EDCA parameter set values for operation on the NPCA primary channel as it uses on the BSS primary channel.

[0135] d)Once the STA becomes ready to transmit on the NPCA primary channel,the STA may initiate a TXOP on the NPCA primary channel by following the rules defined in 10.23.2.2(EDCA backoff procedure)and10.23.2.4(Obtaining an EDCA TXOP)with the following exceptions:

[0136] a.Each time that the STA switches to the NPCA primary channel,it shall initialize CW_NPCA[AC]to TBD value and randomly choose a new initial value between 0and CW_NPCA[AC]for the backoff counter(BO_NPCA[AC]).

[0137] b.QSRC_NPCA[AC]shall be set to 0.

[0138] c.If the STA is a non-AP STA and the associated AP has disabled the use of untriggered UL transmissions on the NPCA primary channel for that STA,then the STA shall not initiate a TXOP on the NPCA primary channel.

[0139] NOTE–The baseline EDCA procedure is followed on the BSS primary channel.The values of CW_NPCA[AC]and BO_NPCA[AC]are discarded by the NPCA STA when it switches back to the BSS primary channel.

[0140] e)The STA shall not initiate a transmission on the NPCA primary channel to another STA until that STA’s NPCA switching delay time has elapsed since the NPCA HE switch time or NPCA NHT switch time,whichever is relevant

[0141] f)The STA shall begin all frame exchanges on the NPCA primary channel with an NPCA initial Control frame using non-HT PPDU or non-HT duplicate PPDU format using a rate of 6Mb / s,12Mb / s,or 24Mb / s.

[0142] g)An NPCA AP that transmits a Trigger frame on the NPCA primary channel shall indicate RU index values that use the NPCA primary channel as the reference primary channel.The Trigger frame shall include an explicit indication that it is being transmitted on the NPCA primary channel.

[0143] h)The 20MHz channels occupied by PPDUs transmitted by the STA while performing NPCA operation on the NPCA primary channel shall meet all of the following conditions:

[0144] a.include at least the NPCA primary channel

[0145] b.all be within the AP’s BSS bandwidth

[0146] c.not include any of the channels occupied by the inter-BSS traffic that caused the STA to switch from the BSS primary channel to the NPCA primary channel

[0147] d.not include the channels that are indicated as punctured in the Disabled Subchannel Bitmap field in the EHT Operation element

[0148] e.a frame that solicits a response other than TB PPDUs may puncture 20MHz subchannels not indicated as punctured in the Disabled Subchannel Bitmap field of the EHT Operation element.

[0149] Referring again to step S320 in Figure 3, after switching to a non-primary channel, the first STA can switch back to the primary channel according to a first rule. This first rule may be related to the timing of the first STA's switchback from the non-primary channel to the primary channel, the duration of the first STA's operation on the non-primary channel, or the number of times the first STA transmits initial control frames (ICFs) or attempts to initiate or acquire TXOPs on the non-primary channel. A detailed description follows. By clearly defining the rule for the first STA to switch back to the primary channel from the non-primary channel, communication reliability can be improved.

[0150] The implementation of the first rule will be illustrated in detail below with several examples.

[0151] Method 1 of implementing the first rule

[0152] In some implementations, the first rule can be related to the moment when the first STA begins to switch from the non-primary channel back to the primary channel. That is, the first rule can be used to limit the moment when the first STA begins to switch from the non-primary channel back to the primary channel, so that the first STA can start switching from the non-primary channel back to the primary channel at an appropriate time. For ease of description, this moment will be referred to as the first moment below.

[0153] The embodiments of this application do not specifically limit the definition of the first moment. It can be determined by protocol predefined information, preconfiguration information, AP in the first BSS, indication information of the first STA, or negotiation between the first STA and the second STA in the first BSS.

[0154] In some implementations, the first rule can be related to the second time. The second time can be the time determined based on the first PPDU. For example, the second time is the time corresponding to the second duration after the third time, and the second duration is determined based on the first PPDU. Here, the third time refers to the NPCA handover time mentioned above, that is, the time when the first STA begins to handover from the primary channel to a non-primary channel. For detailed definitions, please refer to the above, and it will not be repeated here. Exemplarily, the second duration can be the duration of the first PPDU, or the duration of the first PPDU determined based on the preamble in the first PPDU, or the remaining duration of the first PPDU, or the remaining duration of the first PPDU determined based on the preamble in the first PPDU, where the definition of the remaining duration is described above. Alternatively, the second duration can be the duration determined based on the transmission opportunity field of the preamble in the first PPDU, or the duration determined based on the frame duration field in the first PPDU, such as TXOP duration.

[0155] Alternatively, in some implementations, the second duration can be referred to as the expected NPCA operation duration. This expected NPCA operation duration can be determined based on the duration of the first PPDU, the remaining duration of the first PPDU, the duration determined by the transmission opportunity field of the preamble in the first PPDU, or the duration determined by the duration field of the frame in the first PPDU. The definition of the remaining duration is explained above. For example, the expected NPCA operation duration can be equal to the duration of the first PPDU, the remaining duration of the first PPDU, the duration determined by the transmission opportunity field of the preamble in the first PPDU, or the duration determined by the duration field of the frame in the first PPDU. The definition of the remaining duration is explained above. In this implementation, the second moment can be referred to as the expected end moment of the NPCA operation duration.

[0156] The above describes one possible definition of the second time. Other definitions are also possible. For example, in some implementations, the second time is determined based on the target wake-up time service period (TWT SP) or the restricted target wake-up time service period (R-TWT SP) of the second BSS. For instance, the second time can be the end time of the target wake-up time service period of the second BSS. Alternatively, the second time can be the time after adding or subtracting a certain offset from the end time of the target wake-up time service period of the second BSS. Or, the second time can be the end time of the restricted target wake-up time service period of the second BSS. Of course, in this implementation, the first STA needs to first obtain the target wake-up time information or the restricted target wake-up time information of the second BSS. This information can be obtained, for example, through the AP of the first BSS, or by receiving beacon frames from the second BSS.

[0157] In some implementations, the first rule is related to a first moment or a second moment, and may include: the time interval between the first moment and the second moment is greater than or equal to a first duration. Alternatively, the time interval between the first moment and the second moment is less than or equal to the first duration. The first duration may be determined based on one or more of the following: protocol predefined information, negotiation between the first STA and the second STA, indication information sent by the first STA, or indication information sent by the second STA.

[0158] The first duration can be greater than or equal to the handover delay of the first STA switching from the non-primary channel back to the primary channel. The handover delay of the first STA switching from the primary channel to a non-primary channel can be, for example, called the NPCA switching delay, and the handover delay of the first STA switching back to the primary channel can be, for example, called the NPCA switch-back delay. Both of these delays can be defined as values ​​from 0 microseconds to 252 microseconds. For example, both of these delays can be defined as values ​​between 0 microseconds and 252 microseconds in 4-microsecond increments.

[0159] For example, the first rule could include: if the first STA, upon successfully decoding the first SIG field of the first PPDU (which could be either the HE-SIG-A field or the U-SIG field), begins switching to a non-primary channel, then the time interval between the first moment and the second moment is equal to the first duration, and the first duration is equal to the handover delay of the first STA switching back to the primary channel from the non-primary channel. This setting is intended to allow the first STA to remain on the non-primary channel for data transmission for as long as possible, thereby improving data transmission efficiency, because the primary channel is occupied by the first PPDU at this time, and even if the first STA switches back to the primary channel, it cannot transmit.

[0160] For example, the first rule could include: if the first PPDU is an HE PPDU, EHT PPDU, or UHR PPDU, then the time interval between the first moment and the second moment is equal to the first duration, and the first duration is equal to the handover delay of the first STA switching from the non-primary channel back to the primary channel. This setting is to allow the first STA to remain on the non-primary channel for data transmission for as long as possible, thereby improving data transmission efficiency, because the primary channel is occupied by the first PPDU at this time, and even if the first STA switches back to the primary channel, it cannot transmit.

[0161] For example, the first rule could include: if the first STA switches to a non-primary channel at the moment it receives the response frame corresponding to the initial control frame, where the initial control or response frame is carried in the first PPDU mentioned above, then the time interval between the first moment and the second moment is greater than or equal to the first duration, and the first duration is greater than the handover delay of the first STA switching back to the primary channel from the non-primary channel. The fact that the first STA switches to a non-primary channel at the moment it receives the response frame corresponding to the initial control frame indicates that the first STA switched to the non-primary channel because the STA in the second BSS reserved a TXOP of a certain duration on the primary channel through the initial control frame. However, in some cases, the TXOP reserved by the STA may be approximately 3 milliseconds longer than the transmission duration required, and the STA will release the TXOP early using a contention-free end (CF-End) frame after transmission is completed. In this case, if the first STA still operates on the non-primary channel according to the time period indicated by the TXOP duration, it will result in the first STA losing media synchronization when switching back to the primary channel. If media synchronization is lost, the first STA needs to execute the medium access recovery procedure mentioned earlier, which leads to a decrease in transmission efficiency. Therefore, in this situation, a first rule can be set to allow the first STA to return to the main channel earlier, thereby confirming or completing media synchronization in advance and starting transmission on the main channel as soon as possible.

[0162] For example, the first rule could include: if the first PPDU contains a control frame, such as an initial control frame or an initial response frame of a control frame, then the time interval between the first moment and the second moment is greater than or equal to the first duration, and the first duration is greater than the handover delay of the first STA switching back to the primary channel from the non-primary channel. The first STA switching to the non-primary channel at the moment it receives the response frame corresponding to the initial control frame indicates that the first STA switched to the non-primary channel because the STA in the second BSS reserved a TXOP of a certain duration on the primary channel through the initial control frame. However, in some cases, the STA reserves a TXOP of approximately 3 milliseconds longer than it needs for transmission and releases it early using a CF-End frame after transmission is complete. In this case, if the first STA is still operating in NPCA at the time indicated by the TXOP, it will result in the first station losing media synchronization when switching back to the primary channel. Once media synchronization is lost, the first station needs to execute the aforementioned medium access recovery procedure, which will lead to a decrease in transmission efficiency. Therefore, in this situation, by setting a first rule, the first STA can return to the main channel earlier, thereby confirming or completing media synchronization in advance, so as to start transmission on the main channel as soon as possible.

[0163] As described above, setting the first duration to be greater than the handover delay of the first STA from the non-primary channel to the primary channel helps the first STA to switch back to the primary channel as early as possible for media synchronization confirmation or to complete media synchronization as early as possible. This application does not limit the specific setting of the first duration; it can be set to be greater than or equal to the sum of the handover delay from the non-primary channel to the primary channel and the third duration. Several possible settings for the third duration are given below.

[0164] In some implementations, the third duration can be determined based on one or more of the following: protocol predefined information, negotiation between the first STA and the second STA, indication information sent by the first STA, or indication information sent by the second STA.

[0165] In some implementations, this third duration can be greater than or equal to one of the following: the duration corresponding to the medium synchronization threshold (aMediumSyncThreshold), 72 microseconds, 128 microseconds, or a fourth duration. The fourth duration represents the duration corresponding to one ICF and ICR interaction.

[0166] For example, the third duration is equal to the duration corresponding to aMediumSyncThreshold. That is, the first duration is greater than or equal to the sum of the handover delay of the first STA from the non-primary channel to the primary channel (such as NPCA Switch Back Delay) and aMediumSyncThreshold. The value of aMediumSyncThreshold can be 72 microseconds. In this way, after the first STA switches back to the primary channel, it has at least 72 microseconds to receive a short PPDU that the OBSS, including the second BSS, may transmit. For example, a non-HT PPDU or non-HT duplicate PPDU carrying RTS frames, CTS frames, Ack frames, or BlockAck frames and transmitted at a data rate of 6Mb / s. This is beneficial for confirming that media synchronization is maintained or for completing media synchronization as early as possible. For example, if the duration field of the MPDU carried in the short PPDU received by the first STA indicates a time no later than the second time mentioned above, then the first STA confirms that it is maintaining media synchronization on the primary channel. If the duration field of the MPDU carried in the short PPDU received by the first STA indicates a time greater than the second time mentioned above, then the first STA can set or update its own network allocation vector (NAV) value corresponding to the main channel according to the value of the duration field, thereby completing media synchronization.

[0167] For example, the third duration is equal to 128 microseconds. That is, the first duration is greater than or equal to the sum of the handover delay of the first STA from the non-primary channel to the primary channel (such as the NPCA Switch Back Delay) and 128 microseconds. In this way, after switching back to the primary channel, the first STA has at least 128 microseconds to receive a short TB PPDU that the OBSS, including the second BSS, may transmit. This TB PPDU could carry a quality of service null data (QoS Null) frame or a block acknowledgment (BA) frame, which is beneficial for confirming media synchronization or completing media synchronization as early as possible. For example, if the duration field of the MPDU carried in the short TB PPDU received by the first STA indicates a time no later than the second time mentioned above, then the first STA confirms that it is maintaining media synchronization on the primary channel. If the duration field of the MPDU carried in the short TB PPDU received by the first STA indicates a time greater than the second time mentioned above, then the first STA can set or update its own NAV value corresponding to the main channel according to the value of the duration field, thereby completing media synchronization.

[0168] Taking Figure 4 as an example, AP1 and STA1 belong to BSS1, and AP2 and STA2 belong to BSS2. The first STA mentioned earlier can correspond to AP1 in Figure 4, BSS1 can correspond to the first BSS mentioned earlier, and BSS2 can correspond to the second BSS mentioned earlier. BSS1 and BSS2 are each other's OBSS.

[0169] In the scenario shown in Figure 4, AP2 and STA2 preempt the main channel of BSS1 through a random backoff procedure and transmit on that main channel. After preempting the main channel, AP2 sends an RTS to STA2. After receiving the RTS, STA2 returns a CTS to AP2 via SIFS.

[0170] During the transmission of AP2 and STA2 through the main channel, AP1 detects a PPDU containing the RTS or CTS on the main channel of BSS1 (this PPDU may correspond to the first PPDU mentioned above). At this time, AP1 and STA1 begin to switch to the non-main channel or the NPCA main channel at time T0, which is the end time of CTS transmission, and complete the switch before the end of time T1. The time interval between T0 and T1 can be less than or equal to the switching delay of AP1 from the main channel to the NPCA main channel (NPCA switching delay).

[0171] After switching to the NPCA main channel, AP1 preempts the NPCA main channel based on a random backoff procedure and transmits an NPCA ICF to STA1 to initiate or acquire a TXOP. If the ICF transmission fails (STA1 may determine that the NPCA main channel is in a medium busy state and fail to respond to the ICF), AP1 can restart the random backoff procedure and attempt to transmit the NPCA ICF again.

[0172] In Figure 4, time T3 represents the expected end time of the NPCA operation by AP1. This time can be the time elapsed since time T0, corresponding to the expected duration of the NPCA operation. The expected duration of the NPCA operation can be equal to the TXOP duration reserved in the duration field of the RTS frame transmitted by AP2, as mentioned earlier.

[0173] In the event of an NPCA ICF transmission failure at AP1, AP1 can begin switching back to the primary channel at time T2, as shown in Figure 4. This time T2 can be equal to the sum of the following two durations: the NPCA switch-back delay, 72 milliseconds (or 128 milliseconds). Therefore, AP1 will switch back to the primary channel no later than the time corresponding to the NPCA switch-back delay after time T2.

[0174] After switching back to the primary channel, AP1 has at least 72 milliseconds or 128 milliseconds to detect the primary channel to determine whether it is still in a media synchronization state. For example, referring to Figure 4, after switching back to the primary channel, AP1 can receive an ACK or BA frame sent by STA2 to AP2. Then, AP1 confirms based on the ACK or BA frame that the TXOP of AP2 and STA2 will end at time T3. Based on this, AP1 can confirm that it is still in a media synchronization state.

[0175] Taking Figure 5 as an example, AP1 and STA1 belong to BSS1, and AP2 and STA2 belong to BSS2. The first STA mentioned earlier can correspond to AP1 in Figure 5, BSS1 can correspond to the first BSS mentioned earlier, and BSS2 can correspond to the second BSS mentioned earlier. BSS1 and BSS2 are each other's OBSS. AP3 and STA3 can belong to BSS1, BSS2, or BSS3 (each being an OBSS with BSS1).

[0176] In the scenario shown in Figure 5, AP2 and STA2 preempt the main channel of BSS1 through a random backoff procedure and transmit on that main channel. After preempting the main channel, AP2 sends a MU-RTS to STA2. After receiving the RTS, STA2 returns a CTS to AP2 via SIFS.

[0177] During the transmission of AP2 and STA2 through the main channel, AP1 detects a PPDU containing the MU-RTS or CTS on the main channel of BSS1 (this PPDU can correspond to the first PPDU mentioned above). At this time, AP1 and STA1 begin to switch to the non-main channel or the NPCA main channel at time T0, which is the end time of CTS transmission, and complete the switch before the end of time T1. The time interval between T0 and T1 can be less than or equal to the switching delay of AP1 from the main channel to the NPCA main channel (NPCA switching delay).

[0178] After switching to the NPCA main channel, AP1 preempts the NPCA main channel based on a random backoff procedure and transmits an NPCA ICF to STA1 to initiate or acquire a TXOP. If the ICF transmission fails (STA1 may determine that the NPCA main channel is in a medium busy state and fail to respond to the ICF), AP1 can restart the random backoff procedure and attempt to initiate the NPCA ICF again.

[0179] In Figure 5, time T3 represents the expected end time of the NPCA operation by AP1. This time can be the time elapsed since time T0, corresponding to the expected duration of the NPCA operation. The expected duration of the NPCA operation can be equal to the TXOP duration stored in the duration field of the RTS frame mentioned earlier.

[0180] In the event of an NPCA ICF transmission failure at AP1, AP1 can begin switching back to the primary channel at time T2, as shown in Figure 5. This time T2 can be equal to the sum of the following two durations: the NPCA switch-back delay, 72 milliseconds (or 128 milliseconds). Therefore, AP1 will switch back to the primary channel no later than the time corresponding to the NPCA switch-back delay after time T2.

[0181] After switching back to the primary channel, AP1 has at least 72 milliseconds or 128 milliseconds to detect the primary channel to determine whether it is still in a media synchronization state.

[0182] In the example in Figure 5, after AP2 transmits DL data to STA2 and receives an ACK or BA frame from STA2, it prematurely releases the main channel of BSS1 using a CF-End frame. Then, STA3 preempts the main channel of BSS1 based on a random backoff procedure and exchanges frame sequences with AP3 on that main channel. For example, referring to Figure 5, STA3 first sends an RTS to AP3, and after SIFS, receives a CTS returned by AP3. Next, STA3 sends UL data to AP3 and, after SIFS, receives an ACK or BA frame from AP3.

[0183] After switching back to the primary channel, AP1 can detect the primary channel. In the scenario shown in Figure 5, AP1 detects the CTS sent by AP3 to STA3 and determines the remaining duration of frame sequence exchange between AP3 and STA3 based on the duration field in the CTS. Then, AP1 can set or update its own NAV value corresponding to the primary channel according to the value of the duration field, thereby completing media synchronization.

[0184] For example, the third duration equals the fourth duration, which represents the duration corresponding to one ICF and ICR interaction. That is, the first duration is greater than or equal to the sum of the first STA's handover delay from the non-primary channel to the primary channel (e.g., NPCA Switch Back Delay) and the fourth duration. This ensures the first STA has sufficient time to switch back to the primary channel before the second time point, without wasting energy or non-primary channel spectrum resources due to insufficient remaining time to complete one NPCA ICF and NPCA ICR interaction. The fourth duration mentioned here can be determined, for example, based on the transmission duration corresponding to one ICF, the transmission duration corresponding to one ICR, and at least two SIFSs. As an example, the fourth duration can be equal to the transmission duration corresponding to one ICF, the transmission duration corresponding to one ICR, and the sum of two SIFSs ​​(the time, in microseconds, required to transmit one NPCA ICF, plus one NPCA ICR, plus two SIFSs). In this example, the fourth duration is 232 microseconds. As another example, the fourth duration can be equal to the transmission duration of one ICF, the transmission duration of one ICR, and the sum of three SIFS.

[0185] For example, the third duration is greater than or equal to the sum of the fourth and fifth durations. The fourth duration represents the duration corresponding to one ICF and ICR interaction, as detailed above. The fifth duration is greater than or equal to one of the following: the duration corresponding to the medium synchronization threshold (aMediumSyncThreshold), 72 microseconds, or 128 microseconds. In other words, the first duration is greater than or equal to the handover delay of the first STA from the non-primary channel to the primary channel (such as the NPCA Switch Back Delay), the fourth duration, and the fifth duration. In this way, after the first STA switches back to the primary channel, it can confirm that it maintains medium synchronization or completes medium synchronization as early as possible, and also avoids wasting energy and non-primary channel spectrum resources because there is not enough remaining time to complete one NPCA ICF and NPCA ICR interaction.

[0186] Method 2 for implementing the first rule

[0187] In some implementations, the first rule may include that, after switching to a non-primary channel, the duration for which the first STA operates on the non-primary channel is less than or equal to a sixth duration. This sixth duration can be understood as the maximum duration for which the first STA can remain on the non-primary channel. This sixth duration may be determined based on one or more of the following: protocol predefined information, negotiation between the first and second STAs, indication information sent by the first STA, or indication information sent by the second STA.

[0188] The rule that the first STA operates on a non-primary channel for a duration less than or equal to the sixth duration can be triggered by certain conditions. For example, if the first STA switches to a non-primary channel upon receiving the response frame corresponding to the ICF, where the first PPDU mentioned earlier is used to carry the ICF or response frame, then the first STA operates on a non-primary channel for a duration less than or equal to the sixth duration. Alternatively, if the first PPDU contains a control frame, such as an initial control frame or an initial response frame of a control frame, then the first STA operates on a non-primary channel for a duration less than or equal to the sixth duration. This is because if the first STA switches to a non-primary channel upon receiving the response frame corresponding to the ICF, it means that the first STA switched to a non-primary channel because the STA in the second BSS reserved a TXOP of a certain duration on the primary channel through the initial control frame. However, in some cases, the STA reserves a TXOP of approximately 3 milliseconds longer than the transmission duration required, and releases the TXOP early using a CF-End frame after transmission is complete. In this scenario, if the first STA is still operating on the NPCA at the time indicated by the TXOP, it will result in a loss of media synchronization when switching back to the primary channel. Once media synchronization is lost, the first STA needs to execute the aforementioned medium access recovery procedure, which may lead to a decrease in transmission efficiency. Therefore, limiting the maximum duration the first STA stays on the non-primary channel in this situation allows it to return to the primary channel earlier, thereby confirming or completing media synchronization in advance and starting transmission on the primary channel as soon as possible.

[0189] After the first STA switches from the primary channel to a non-primary channel, it can send an ICF (Initial Communication Message) on the non-primary channel to initiate or acquire a TXOP (Transmission of TX). In some implementations, the first STA can follow the rule that its stay on the non-primary channel does not exceed the sixth duration after an ICF transmission failure. Alternatively, regardless of whether the ICF transmission succeeds or fails, the first STA's stay on the non-primary channel must not exceed the sixth duration.

[0190] Method 3 of implementing the first rule

[0191] In some implementations, the switching conditions for the first STA from the non-primary channel to the primary channel can be defined, so that the first STA switches back to the primary channel when one or more conditions (hereinafter referred to as the first condition for ease of description) are met, so as to confirm or complete the media synchronization in advance, thereby starting transmission on the primary channel as early as possible.

[0192] This application does not specifically limit the content of the first condition in its embodiments. For example, the first condition may be related to one or more of the following: the busy / idle state of the non-primary channel, whether the first STA successfully transmits the ICF on the non-primary channel, whether the first STA receives the PPDU of the third BSS on the non-primary channel, whether the first STA receives the first ICF on the non-primary channel and the target STA of the first ICF does not include the first STA, and whether the first STA receives the second ICF on the non-primary channel and the second ICF is used to trigger the first STA to transmit data. The first condition will be illustrated in more detail below.

[0193] In some implementations, the first condition includes: after the first STA switches from the primary channel to a non-primary channel, the first STA determines that the non-primary channel is busy. Alternatively, the first condition includes: after the first STA switches from the primary channel to a non-primary channel, the first STA determines that the duration of the non-primary channel being busy is greater than or equal to a seventh duration. For example, after the first STA switches to a non-primary channel, if it does not compete for the non-primary channel or the medium for the non-primary channel within the seventh duration (e.g., the non-primary channel is occupied by OBSS transmissions and is in a busy state), or if the first STA learns that the duration of OBSS transmissions occupying the non-primary channel will exceed the seventh duration, then the first STA can switch back to the primary channel. The seventh duration mentioned here can be determined based on one or more of the following: protocol predefined information, negotiation between the first STA and the second STA, indication information sent by the first STA, or indication information sent by the second STA. Furthermore, in some implementations, the seventh duration can be a value that increases in increments of 72 microseconds, such as 1024 microseconds, 1096 microseconds, and so on up to 2608 microseconds (1024 + 72 * 22). The seventh duration can also be a value that increases in increments of 128 microseconds, such as 1024 microseconds, 1148 microseconds, and so on up to 2560 microseconds.

[0194] In some implementations, the first condition includes: after the first STA switches from the primary channel to a non-primary channel, the first STA fails to successfully transmit the ICF. Alternatively, the first condition includes: after the first STA switches from the primary channel to a non-primary channel, the first STA fails to successfully transmit the ICF within an eighth duration. The eighth duration mentioned here can be determined based on one or more of the following: protocol predefined information, negotiation between the first and second STAs, indication information sent by the first STA, or indication information sent by the second STA. Furthermore, in some implementations, the eighth duration can be a value increasing in increments of 72 microseconds, such as 1024 microseconds, 1096 microseconds, and so on up to 2608 microseconds (1024 + 72 * 22). The eighth duration can also be a value increasing in increments of 128 microseconds, such as 1024 microseconds, 1148 microseconds, and so on up to 2560 microseconds.

[0195] In some implementations, the first condition includes: after switching to a non-primary channel, the first STA receives a PPDU (or inter-BSS PPDU) from the third BSS. Upon receiving this PPDU from the third BSS, the first STA can switch back from the non-primary channel to the primary channel. Alternatively, after receiving the PPDU from the third BSS, if the duration of the non-primary channel being busy is determined based on the PPDU from the third BSS to be greater than or equal to a ninth duration, then the first STA can switch back from the non-primary channel to the primary channel. The ninth duration mentioned here can be determined based on one or more of the following: protocol predefined information, negotiation between the first and second STAs, indication information sent by the first STA, or indication information sent by the second STA. Furthermore, in some implementations, the ninth duration can be a value that increases in increments of 72 microseconds, such as 1024 microseconds, 1096 microseconds, and so on up to 2608 microseconds (1024 + 72 * 22). The ninth duration can also be a value that increases in increments of 128 microseconds, such as 1024 microseconds, 1148 microseconds, and so on up to 2560 microseconds. The duration at which a non-primary channel is busy, determined based on the PPDU of the third BSS, is greater than or equal to the ninth duration. This can include, for example, the duration or remaining duration of the PPDU of the third BSS being greater than or equal to the ninth duration; or the duration or remaining duration of the PPDU indicated by the LENGTH field and / or RATE field and / or HE-MCS field and / or EHT-SIG MCS field and / or UHR-SIG MCS field in the preamble of the third BSS being greater than or equal to the ninth duration; or the duration of the reserved TXOP indicated by the TXOP field in the preamble of the third BSS being greater than or equal to the ninth duration; or the duration of the reserved TXOP indicated by the Duration field in the frame of the third BSS being greater than or equal to the ninth duration.

[0196] In some implementations, the first condition includes: after switching to a non-primary channel, the first STA receives a first ICF (Individually Addressed Frame), where the first ICF is an individually addressed frame, meaning the receiver address (RA) field in the MAC header of the first ICF indicates a unicast address, and the MAC address indicated by the RA field in the MAC header of the first ICF is different from the MAC address of the first STA; that is, the first STA is not the target STA of the first ICF. In other words, after switching to a non-primary channel, if the first STA receives the first ICF, where the first ICF is an individually addressed frame, and the MAC address in the RA field of the MAC header of the first ICF is different from the MAC address of the first STA, then the first STA switches back from the non-primary channel to the primary channel.

[0197] In some implementations, the first condition includes: after switching to a non-primary channel, the first STA receives a first ICF (Initial Class Frame), where the first ICF is a broadcast frame or a group-addressed frame; that is, the RA field in the MAC header of the first ICF indicates a broadcast address or multicast address, and the AID indicated by the user information field of the first ICF frame does not include the AID of the first STA. In other words, after switching to a non-primary channel, if the first STA receives the first ICF, the RA field in the MAC header of the first ICF indicates a broadcast address or multicast address, and the AID indicated by the user information field of the first ICF frame does not include the AID of the first STA, meaning the first STA is not the target STA of the first ICF, then the first STA switches back from the non-primary channel to the primary channel.

[0198] In some implementations, the first condition includes: the first STA uses a triggered UL transmission only mode or does not use untriggered UL transmissions, and after switching to a non-primary channel, the first STA does not receive a second ICF within a tenth time period. That is, if the first STA uses a triggered UL transmission only mode or does not use untriggered UL transmissions, and after switching to a non-primary channel, the first STA does not receive a second ICF within a tenth time period, then the first STA switches back to the primary channel from the non-primary channel. It should be understood that the "triggered UL transmission only mode" or "does not use untriggered UL transmissions" mentioned above can be enabled by the AP of the first BSS. Furthermore, the tenth time period mentioned above can be determined based on one or more of the following: protocol predefined information, negotiation between the first STA and the second STA, indication information sent by the first STA, or indication information sent by the second STA. Furthermore, in some implementations, the tenth duration can be a value that increases in increments of 72 microseconds, such as 1024 microseconds, 1096 microseconds (1024 microseconds + 72 microseconds * n, where n is the number of increments), and so on up to 2608 microseconds (1024 microseconds + 72 microseconds * 22). The tenth duration can also be a value that increases in increments of 128 microseconds, such as 1024 microseconds, 1148 microseconds (1024 microseconds + 128 microseconds * n, where n is the number of increments), and so on up to 2560 microseconds.

[0199] The fourth way to implement the first rule

[0200] The first rule can be related to the number of times a first STA is allowed to initiate or acquire transmission opportunities on a non-primary channel.

[0201] For example, the duration of a transmission opportunity is limited, and its specific value is indicated by the EDCA parameter set element in the beacon and probe response frames of the AP. For example, the duration limit for a transmission opportunity for data transmission in the audio access category (AC_VO) may be 2080 microseconds, for the video access category (AC_VI) it is 4096 microseconds, and for the background traffic category (AC_BK) or best-effort category (AC_BE) it is 2528 microseconds.

[0202] The duration of a PPDU is also finite, defined by the internal constant aPPDUMaxTime of the STA, which can be a non-AP STA or AP. For example, the maximum duration of an HT PPDU is 10,000 microseconds, while the maximum duration of a VHT PPDU, HE PPDU, EHT PPDU, and UHR PPDU is 5,484 microseconds.

[0203] If the first STA is a non-AP STA, then the first STA needs at least one distributed coordination function interframe space (DIFS) of 34 microseconds for one channel contention.

[0204] If the first STA is an AP, then a contention by the first STA requires at least one priority interframe space (PIFS) of about 25 microseconds.

[0205] A single interaction between an NPCA ICF and an NPCA ICR on a non-primary channel requires a minimum of approximately 232 microseconds.

[0206] The first STA switching to a non-primary channel requires the duration indicated by the NPCA switching delay, for example, 32 microseconds. The first STA switching back to the primary channel requires the duration indicated by the NPCA switching back delay, for example, 32 microseconds.

[0207] If the first STA detects an inter-BSS HE PPDU, EHT PPDU, or UHR PPDU, the first STA must receive the entire traditional preamble of that first PPDU (including the L-STF, L-LTF, L-SIG, and RL-SIG fields) before initiating the handover. This reception process of the traditional preamble takes at least approximately 16 microseconds. In this case, if the first STA is an AP, it can theoretically attempt to acquire transmission opportunities on a non-primary channel a maximum of 21 times. If the first STA is a non-AP STA, then theoretically it can attempt to acquire transmission opportunities a maximum of 20 times on a non-primary channel, that is...

[0208] If the first STA detects a PPDU containing an initial control frame, the first STA must wait for at least one ICF and ICR interaction before it can begin switching from the primary channel to a non-primary channel, a process that takes approximately 232 microseconds. In this case, if the first STA is an AP, it can theoretically attempt to acquire transmission opportunities on the non-primary channel a maximum of 14 times, i.e. If the first STA is a non-AP STA, then theoretically it can attempt to acquire transmission opportunities a maximum of 14 times on a non-primary channel, i.e.

[0209] As mentioned earlier, in some cases, the STA in the second BSS reserves a transmission opportunity for approximately 3 milliseconds longer than the time required for transmission, and will release this opportunity early using a CF-End frame after transmission is complete. In this case, the first STA should ideally switch back to the primary channel before the transmission opportunity reserved by the second BSS is released. Therefore, considering this factor, if the first STA is an AP, the access point can theoretically attempt to acquire a transmission opportunity on a non-primary channel a maximum of 3 times, i.e. If the first STA is a non-AP STA, then theoretically it can attempt to acquire transmission opportunities a maximum of 3 times on a non-primary channel.

[0210] Based on the preceding description, in some implementations, the first rule may include: after switching to a non-primary channel, the first STA shall not attempt to initiate a TXOP more than dot11NPCATXOPMax times since the start of the NPCA operation. Alternatively, after switching to a non-primary channel, the first STA shall be allowed to transmit ICFs less than or equal to the first number of times, where ICFs are used to initiate or acquire transmission opportunities. This first number may include 1, 2, 3, or 4, etc.

[0211] Furthermore, in some implementations, the aforementioned first rule can be triggered under certain conditions. For example, if the first STA switches to a non-primary channel at the moment it receives the response frame corresponding to the initial control frame, where the first PPDU mentioned above is used to carry the initial control frame or response frame, then after switching to the non-primary channel, the number of times the first STA is allowed to initiate or acquire transmission opportunities on the non-primary channel is less than or equal to the first number.

[0212] In some implementations, the first rule may include that if the first STA fails to transmit the ICF on the first attempt on a non-primary channel, the first STA is allowed to re-initiate or acquire a transmission opportunity less than or equal to the second number. Alternatively, after switching to a non-primary channel, if the first STA fails to transmit the ICF on the first attempt on the non-primary channel, the first STA is allowed to re-transmit the ICF on the non-primary channel less than or equal to the second number, where the ICF is used to initiate or acquire a transmission opportunity. This second number may include 0, 1, 2, or 3, etc.

[0213] Furthermore, in some implementations, the aforementioned first rule can be triggered under certain conditions. For example, if the first STA switches to a non-primary channel at the moment it receives the response frame corresponding to the initial control frame, where the first PPDU mentioned above is used to carry the initial control frame or response frame, then after switching to the non-primary channel, if the first STA fails to transmit the ICF for the first time on the non-primary channel, the number of times the first STA is allowed to initiate or obtain a transmission opportunity again is less than or equal to the second time.

[0214] In some implementations, the first STA knows in advance the target wake-up time and / or restricted target wake-up time information of the second BSS. If the first STA fails to transmit ICF on a non-primary channel during the target wake-up time service period of the second BSS or the restricted target wake-up time service period, the first STA may not be subject to the aforementioned first or second count. For example, the first STA may determine the time to switch from the non-primary channel to the primary channel according to the first duration mentioned above.

[0215] It should be noted that the preceding text mentioned multiple implementations of the first rule, which can be used individually or in combination. For example, while satisfying the first duration limit mentioned above, the number of times the first STA can attempt to initiate or acquire transmission opportunities on a non-primary channel can also be limited. As an example, if the remaining time is sufficient to attempt to initiate transmission opportunities four times while satisfying the first duration limit, but the first rule limits the total number of times the first STA can attempt to initiate transmission opportunities on a non-primary channel to no more than two, then the first STA can only attempt to initiate transmission opportunities a maximum of two times. As another example, if the remaining time is sufficient to attempt to initiate transmission opportunities four times while satisfying the first duration limit, but the first rule limits the total number of times the first STA can attempt to initiate transmission opportunities on a non-primary channel to no more than five, then the first STA can attempt to initiate transmission opportunities a maximum of four times.

[0216] It should be noted that in some implementations, the first STA can decide when to switch back to the primary channel. For example, if the first STA fails to transmit ICF data on a non-primary channel, it can decide to initiate a backoff procedure or immediately switch back to the primary channel.

[0217] It should be noted that the first rule provided in each embodiment of this application can be implemented in the event of ICF transmission failure on the non-primary channel of the first STA. The method for determining ICF transmission failure can be found in the description of the "Transmission Failure" section above. When ICF transmission failure occurs, if the first STA does not choose to immediately switch back to the primary channel, the first STA can execute a backoff procedure.

[0218] The method embodiments of this application have been described in detail above. The apparatus embodiments of this application are described in detail below. It should be understood that the descriptions of the method embodiments correspond to the descriptions of the apparatus embodiments. Therefore, any parts not described in detail can be referred to the foregoing method embodiments.

[0219] Figure 6 is a schematic structural diagram of a communication device 600 provided in an embodiment of this application. The communication device 600 is a first STA, and the first STA includes a processing module 610. The processing module 610 is used to switch from the primary channel of the first BSS to a non-primary channel in response to the first STA of the first BSS receiving a first PPDU, wherein the first PPDU is a PPDU transmitted by the second BSS; after switching to the non-primary channel, it switches back to the primary channel according to a first rule.

[0220] In this embodiment, the communication device 600 can be used to execute some or all of the method steps performed by the first STA in the above method embodiments. The communication device 600 includes units or modules for executing the aforementioned method steps. The method flow has been described in detail in the foregoing embodiments. The modules in this embodiment have the same function or perform the same steps, and will not be described again here. However, those skilled in the art should know that the textual descriptions corresponding to the foregoing method embodiments can be incorporated into this embodiment and correspond to the modules in the communication device 600.

[0221] In an optional embodiment, the processing module 610 may be a processor. The communication device 600 may also include a memory and a transceiver, as shown in FIG7.

[0222] Figure 7 is a schematic structural diagram of a communication device according to an embodiment of this application. The dashed lines in Figure 7 indicate that the unit or module is optional. This device 700 can be used to implement the methods described in the above method embodiments. The device 700 can be a chip or a communication device.

[0223] The apparatus 700 may include one or more processors 710. The processor 710 may support the apparatus 700 in implementing the methods described in the preceding method embodiments. The processor 710 may be a general-purpose processor or a special-purpose processor. For example, the processor may be a central processing unit (CPU). Alternatively, the processor may be other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or any conventional processor.

[0224] The apparatus 700 may also include one or more memories 720. The memories 720 store a program that can be executed by the processor 710, causing the processor 710 to perform the methods described in the preceding method embodiments. The memories 720 may be independent of the processor 710 or integrated within the processor 710.

[0225] The device 700 may also include a transceiver 730. The processor 710 can communicate with other devices or chips via the transceiver 730. For example, the processor 710 can send and receive data with other devices or chips via the transceiver 730.

[0226] This application also provides a computer-readable storage medium for storing a program. This computer-readable storage medium can be applied to the communication device provided in this application, and the program causes a computer to execute the methods performed by the communication device in various embodiments of this application.

[0227] This application also provides a computer program product. The computer program product includes a program. The computer program product can be applied to the communication device provided in this application embodiment, and the program causes a computer to execute the methods performed by the communication device in various embodiments of this application.

[0228] This application also provides a computer program. This computer program can be applied to the communication device provided in this application, and causes the computer to execute the methods performed by the communication device in various embodiments of this application.

[0229] It should be understood that the terms "system" and "network" in this application can be used interchangeably. Furthermore, the terminology used in this application is only for explaining specific embodiments of the application and is not intended to limit the application. The terms "first," "second," "third," and "fourth," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish different objects, not to describe a specific order. In addition, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion.

[0230] In the embodiments of this application, a "field" may also be referred to as a "domain", "subfield", or "subfield". A field may occupy one or more bytes (byte / octet), or a field may occupy one or more bits (bit).

[0231] The field names defined in the embodiments of this application are merely examples, and the field may have other names.

[0232] In the embodiments of this application, the term "instruction" can be a direct instruction, an indirect instruction, or an indication of a relationship. For example, A instructing B can mean that A directly instructs B, such as B being able to obtain information through A; it can also mean that A indirectly instructs B, such as A instructing C, so B can obtain information through C; or it can mean that there is a relationship between A and B.

[0233] In the embodiments of this application, "B corresponding to A" means that B is associated with A, and B can be determined based on A. However, it should also be understood that determining B based on A does not mean that B is determined solely based on A; B can also be determined based on A and / or other information.

[0234] In the embodiments of this application, the term "correspondence" can indicate a direct or indirect correspondence between two things, or an association between two things, or a relationship such as instruction and being instructed, configuration and being configured.

[0235] In this application embodiment, "predefined" or "preconfigured" can be implemented by pre-storing corresponding codes, tables, or other means that can be used to indicate relevant information in the device (e.g., including AP and STA). This application does not limit the specific implementation method. For example, predefined can refer to what is defined in the protocol.

[0236] In the embodiments of this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0237] In the embodiments of this application, "comprising" can refer to direct inclusion or indirect inclusion. Optionally, "comprising" mentioned in the embodiments of this application can be replaced with "indicating" or "used to determine". For example, "A includes B" can be replaced with "A indicates B" or "A is used to determine B".

[0238] In the various embodiments of this application, the order of the above-mentioned processes does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0239] In this application embodiment, the "protocol" may refer to a standard protocol in the field of communication, such as the 802.11 (WIFI) protocol and related protocols applied to future 802.11 (WIFI) communication systems. This application does not limit this.

[0240] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0241] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0242] In addition, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0243] In the above embodiments, implementation can be achieved entirely or partially through software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented entirely or partially in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of this application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium that a computer can read or a data storage device such as a server or data center that integrates one or more available media. The available media may be magnetic media (e.g., floppy disks, hard disks, magnetic tapes), optical media (e.g., digital video discs, DVDs) or semiconductor media (e.g., solid-state disks, SSDs), etc.

[0244] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A communication method, characterized in that, include: In response to the first STA of the first basic service set (BSS) receiving the first physical layer protocol data unit (PPDU), the first STA switches from the primary channel of the first BSS to a non-primary channel. The first PPDU is a PPDU transmitted by the second BSS. After switching to the non-primary channel, the first STA switches back to the primary channel from the non-primary channel according to the first rule.

2. The method according to claim 1, characterized in that, The first rule includes that the time interval between the first moment and the second moment is greater than or equal to the first duration; Wherein, the first moment is the moment when the first STA begins to switch back from the non-primary channel to the primary channel; The second time is determined based on the first PPDU, or the second time is determined based on the target wake-up time service period or the restricted target wake-up time service period of the second BSS.

3. The method according to claim 2, characterized in that, The second time, determined based on the first PPDU, includes: the second time being the time corresponding to the second duration after the third time, wherein the third time is the time when the first STA begins to switch from the main channel to the non-main channel, and the second duration is determined based on the first PPDU.

4. The method according to claim 3, characterized in that, The second duration is one of the following: the duration of the first PPDU, the duration of the first PPDU determined based on the preamble in the first PPDU, the remaining duration of the first PPDU, the remaining duration of the first PPDU determined based on the preamble in the first PPDU, the duration determined based on the transmission opportunity field of the preamble in the first PPDU, and the duration determined based on the duration field of the frame in the first PPDU.

5. The method according to claim 2, characterized in that, The second time is determined based on the target wake-up time service period or the restricted target wake-up time service period of the second BSS, including: the second time is the end time of the target wake-up time service period of the second BSS or the end time of the restricted target wake-up time service period.

6. The method according to any one of claims 2 to 5, characterized in that, The first duration is greater than or equal to the switching delay of the first STA switching back to the primary channel from the non-primary channel.

7. The method according to claim 6, characterized in that, The first rule includes: if the first STA starts switching to the non-master channel when it successfully decodes the first signal SIG field of the first PPDU, then the time interval between the first time and the second time is equal to the first duration, wherein the first duration is equal to the switching delay.

8. The method according to claim 6, characterized in that, The first duration is greater than or equal to the sum of the switching delay and the third duration, wherein the third duration is greater than or equal to one of the following: The duration corresponding to the media synchronization threshold; 72 microseconds; 128 microseconds; The fourth duration represents the duration of an initial control frame (ICF) and initial control response (ICR) frame interaction.

9. The method according to claim 8, characterized in that, The fourth duration is determined based on the following durations: the transmission duration corresponding to one ICF, the transmission duration corresponding to one ICR, and at least two SIFS.

10. The method according to claim 8 or 9, characterized in that, The third duration is greater than or equal to the sum of the fourth and fifth durations, and the fifth duration is greater than or equal to one of the following: The duration corresponding to the media synchronization threshold; 72 microseconds; 128 microseconds.

11. The method according to any one of claims 6 and 8 to 10, characterized in that, The first rule includes: if the first STA switches to the non-primary channel at the moment it receives the response frame corresponding to the initial control frame, then the first duration is greater than the switching delay; wherein, the first PPDU is used to carry the initial control frame or the response frame.

12. The method according to any one of claims 2 to 11, characterized in that, The first duration is determined based on one or more of the following: protocol predefined information, negotiation between the first STA and the second STA, indication information sent by the first STA, or indication information sent by the second STA.

13. The method according to any one of claims 1 to 12, characterized in that, The first rule includes that after switching to the non-primary channel, the first STA operates on the non-primary channel for a duration less than or equal to a sixth duration.

14. The method according to claim 13, characterized in that, The first rule includes: if the first STA switches to the non-primary channel at the moment it receives the response frame corresponding to the initial control frame, then the duration for which the first STA operates on the non-primary channel is less than or equal to the sixth duration, wherein the first PPDU is used to carry the initial control frame or the response frame.

15. The method according to any one of claims 1 to 14, characterized in that, The first rule includes that after switching to the non-primary channel, if a first condition is met, the first STA switches back to the primary channel from the non-primary channel; The first condition is related to one or more of the following: The busy / idle status of the non-master channel; Did the first STA successfully transmit ICF on the non-master channel? Whether the first STA receives the PPDU of the third BSS on the non-primary channel; Whether the first STA receives the first ICF on the non-master channel, and whether the target STA of the first ICF does not include the first STA; Whether the first STA receives the second ICF on the non-master channel, and whether the second ICF is used to trigger the first STA to perform data transmission.

16. The method according to claim 15, characterized in that, The first condition includes one or more of the following: After switching to the non-primary channel, the first STA determines that the duration of the non-primary channel being busy is greater than or equal to the seventh duration; After switching to the non-primary channel, the first STA failed to successfully transmit ICF within the eighth time period; After switching to the non-primary channel, the first STA receives the PPDU from the third BSS; After switching to the non-primary channel, the first STA receives the PPDU of the third BSS and determines, based on the PPDU of the third BSS, that the duration of the non-primary channel being busy is greater than or equal to the ninth duration. After switching to the non-primary channel, the first STA receives the first ICF, which is a separately addressed frame, and the Media Access Control MAC address in the Receiver Address RA field of the MAC header of the first ICF is different from the MAC address of the first STA. After switching to the non-primary channel, the first STA receives the first ICF. The RA field in the MAC header of the first ICF indicates the broadcast address or multicast address, and the AID indicated by the user information field of the first ICF frame does not include the AID of the first STA. The first STA uses a trigger-based uplink transmission mode or does not use a non-trigger uplink transmission, and after switching to the non-primary channel, the first STA does not receive the second ICF within a tenth time period.

17. The method according to any one of claims 1 to 16, characterized in that, The first rule includes one or more of the following: After switching to the non-primary channel, the first STA is allowed to initiate or acquire transmission opportunities on the non-primary channel a number that is less than or equal to the number of times it was the first time. or, If the first STA fails to transmit ICF on the first non-main channel, the first STA is allowed to initiate or acquire transmission opportunities again less than or equal to the second number.

18. The method according to claim 17, characterized in that: The first number is determined based on one or more of the following: protocol predefined information, negotiation between the first STA and the second STA, indication information sent by the first STA, or indication information sent by the second STA; And / or, The second number is determined based on one or more of the following: protocol predefined information, negotiation between the first STA and the second STA, indication information sent by the first STA, or indication information sent by the second STA.

19. The method according to claim 17 or 18, characterized in that: The first number is equal to 1, 2 or 3 The second number is equal to 0, 1, or 2.

20. The method according to any one of claims 17 to 19, characterized in that, The first STA is a non-access point STA, an access point, a non-access point multi-link device, or an access point multi-link device.

21. A communication device, characterized in that, The communication device is a first station (STA), and the first STA includes: The processing module is configured to, in response to a first STA of a first basic service set (BSS) receiving a first physical layer protocol data unit (PPDU), switch from the primary channel of the first BSS to a non-primary channel, wherein the first PPDU is a PPDU transmitted by a second BSS; and after switching to the non-primary channel, switch back to the primary channel according to a first rule.

22. The communication device according to claim 21, characterized in that, The first rule includes that the time interval between the first moment and the second moment is greater than or equal to the first duration; Wherein, the first moment is the moment when the first STA begins to switch back from the non-primary channel to the primary channel; The second time is determined based on the first PPDU, or the second time is determined based on the target wake-up time service period or the restricted target wake-up time service period of the second BSS.

23. The communication device according to claim 22, characterized in that, The second time, determined based on the first PPDU, includes: the second time being the time corresponding to the second duration after the third time, wherein the third time is the time when the first STA begins to switch from the main channel to the non-main channel, and the second duration is determined based on the first PPDU.

24. The communication device according to claim 23, characterized in that, The second duration is one of the following: the duration of the first PPDU, the duration of the first PPDU determined based on the preamble in the first PPDU, the remaining duration of the first PPDU, the remaining duration of the first PPDU determined based on the preamble in the first PPDU, the duration determined based on the transmission opportunity field of the preamble in the first PPDU, and the duration determined based on the duration field of the frame in the first PPDU.

25. The communication device according to claim 22, characterized in that, The second time is determined based on the target wake-up time service period or the restricted target wake-up time service period of the second BSS, including: the second time is the end time of the target wake-up time service period of the second BSS or the end time of the restricted target wake-up time service period.

26. The communication device according to any one of claims 22 to 25, characterized in that, The first duration is greater than or equal to the switching delay of the first STA switching back to the primary channel from the non-primary channel.

27. The communication device according to claim 26, characterized in that, The first rule includes: if the first STA starts switching to the non-master channel when it successfully decodes the first signal SIG field of the first PPDU, then the time interval between the first time and the second time is equal to the first duration, wherein the first duration is equal to the switching delay.

28. The communication device according to claim 26, characterized in that, The first duration is greater than or equal to the sum of the switching delay and the third duration, wherein the third duration is greater than or equal to one of the following: The duration corresponding to the media synchronization threshold; 72 microseconds; 128 microseconds; The fourth duration represents the duration of an initial control frame (ICF) and initial control response (ICR) frame interaction.

29. The communication device according to claim 28, characterized in that, The fourth duration is determined based on the following durations: the transmission duration corresponding to one ICF, the transmission duration corresponding to one ICR, and at least two SIFS.

30. The communication device according to claim 28 or 29, characterized in that, The third duration is greater than or equal to the sum of the fourth and fifth durations, and the fifth duration is greater than or equal to one of the following: The duration corresponding to the media synchronization threshold; 72 microseconds; 128 microseconds.

31. The communication device according to any one of claims 26 and 28 to 30, characterized in that, The first rule includes: if the first STA switches to the non-primary channel at the moment it receives the response frame corresponding to the initial control frame, then the first duration is greater than the switching delay; wherein, the first PPDU is used to carry the initial control frame or the response frame.

32. The communication device according to any one of claims 22 to 31, characterized in that, The first duration is determined based on one or more of the following: protocol predefined information, negotiation between the first STA and the second STA, indication information sent by the first STA, or indication information sent by the second STA.

33. The communication device according to any one of claims 21 to 32, characterized in that, The first rule includes that after switching to the non-primary channel, the first STA operates on the non-primary channel for a duration less than or equal to a sixth duration.

34. The communication device according to claim 23, characterized in that, The first rule includes: if the first STA switches to the non-primary channel at the moment it receives the response frame corresponding to the initial control frame, then the duration for which the first STA operates on the non-primary channel is less than or equal to the sixth duration, wherein the first PPDU is used to carry the initial control frame or the response frame.

35. The communication device according to any one of claims 21 to 34, characterized in that, The first rule includes that after switching to the non-primary channel, if a first condition is met, the first STA switches back to the primary channel from the non-primary channel; The first condition is related to one or more of the following: The busy / idle status of the non-master channel; Did the first STA successfully transmit ICF on the non-master channel? Whether the first STA receives the PPDU of the third BSS on the non-primary channel; Whether the first STA receives the first ICF on the non-master channel, and whether the target STA of the first ICF does not include the first STA; Whether the first STA receives the second ICF on the non-master channel, and whether the second ICF is used to trigger the first STA to perform data transmission.

36. The communication device according to claim 35, characterized in that, The first condition includes one or more of the following: After switching to the non-primary channel, the first STA determines that the duration of the non-primary channel being busy is greater than or equal to the seventh duration; After switching to the non-primary channel, the first STA failed to successfully transmit ICF within the eighth time period; After switching to the non-primary channel, the first STA receives the PPDU from the third BSS; After switching to the non-primary channel, the first STA receives the PPDU of the third BSS and determines, based on the PPDU of the third BSS, that the duration of the non-primary channel being busy is greater than or equal to the ninth duration. After switching to the non-primary channel, the first STA receives the first ICF, which is a separately addressed frame, and the Media Access Control MAC address in the Receiver Address RA field of the MAC header of the first ICF is different from the MAC address of the first STA. After switching to the non-primary channel, the first STA receives the first ICF. The RA field in the MAC header of the first ICF indicates the broadcast address or multicast address, and the AID indicated by the user information field of the first ICF frame does not include the AID of the first STA. The first STA uses a trigger-based uplink transmission mode or does not use a non-trigger uplink transmission, and after switching to the non-primary channel, the first STA does not receive the second ICF within a tenth time period.

37. The communication device according to any one of claims 21 to 36, characterized in that, The first rule includes one or more of the following: After switching to the non-primary channel, the first STA is allowed to initiate or acquire transmission opportunities on the non-primary channel a number that is less than or equal to the number of times it was the first time. or, If the first STA fails to transmit ICF on the first non-main channel, the first STA is allowed to initiate or acquire transmission opportunities again less than or equal to the second number.

38. The communication device according to claim 37, characterized in that: The first number is determined based on one or more of the following: protocol predefined information, negotiation between the first STA and the second STA, indication information sent by the first STA, or indication information sent by the second STA; And / or, The second number is determined based on one or more of the following: protocol predefined information, negotiation between the first STA and the second STA, indication information sent by the first STA, or indication information sent by the second STA.

39. The communication device according to claim 37 or 38, characterized in that: The first number is equal to 1, 2 or 3 The second number is equal to 0, 1, or 2.

40. The communication device according to any one of claims 37 to 39, characterized in that, The first STA is a non-access point STA, an access point, a non-access point multi-link device, or an access point multi-link device.

41. A communication device, characterized in that, The device includes a transceiver, a memory, and a processor. The memory stores a program, and the processor invokes the program in the memory and controls the transceiver to receive or transmit signals so that the communication device performs the method as described in any one of claims 1 to 20.

42. An apparatus, characterized in that, Includes a processor for calling a program from memory to cause the apparatus to perform the method as described in any one of claims 1 to 20.

43. A chip, characterized in that, Includes a processor for calling a program from memory, causing a device on which the chip is mounted to perform the method as described in any one of claims 1 to 20.

44. A computer-readable storage medium, characterized in that, It contains a program that causes a computer to perform the method as described in any one of claims 1 to 20.

45. A computer program product, characterized in that, Includes a program that causes a computer to perform the method as described in any one of claims 1 to 20.

46. ​​A computer program, characterized in that, The computer program causes the computer to perform the method as described in any one of claims 1 to 20.

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