NPCA-based channel access method and apparatus, device, and medium

Abstract

The present application relates to the field of WiFi, and discloses an NPCA-based channel access method and apparatus, a device, a medium, and a program product. The method is executed by a first station. The method comprises: during switching from a BSS primary channel to an NPCA primary channel, determining whether to start a medium synchronization recovery procedure or to perform channel access without losing medium synchronization. In the method, when the first station switches from the BSS primary channel to the NPCA primary channel, it is determined whether to start the medium synchronization recovery procedure or to perform channel access without losing medium synchronization. If it is determined to start the medium synchronization recovery procedure or to perform channel access with medium synchronization lost, medium synchronization on the NPCA primary channel can be ensured; and if it is determined not to start the medium synchronization recovery procedure or to perform channel access without losing medium synchronization, it is indicated that there is no medium synchronization problem on the NPCA primary channel.

Description

NPCA-based channel access methods, apparatus, devices, and media Technical Field

[0001] This application relates to the field of Wireless-Fidelity (Wi-Fi), and in particular to a channel access method, apparatus, device, medium, and program product based on Non-Primary Channel Access (NPCA). Background Technology

[0002] The Non-Primary Channel Access (NPCA) mechanism allows a site to switch to the NPCA operating channel to perform data transmission when the primary channel is busy due to Overlapping Basic Service Set (OBSS) traffic or other conditions.

[0003] Since access point and non-access point sites originally operated on the Basic Service Set (BSS) operation channel, they could not perform listening operations and idle channel evaluation operations on the NPCA operation channel. Therefore, when access point and non-access point sites switch to the NPCA operation channel at the same time, there is a problem that media synchronization cannot be guaranteed on the NPCA operation channel. Summary of the Invention

[0004] This application provides a channel access method, apparatus, device, medium, and program product based on NPCA, which includes at least:

[0005] According to one aspect of the embodiments of this application, a channel access method based on NPCA is provided, the method being executed by a first site, the method comprising:

[0006] In the event of switching from the BSS primary channel to the NPCA primary channel, determine whether to initiate the media synchronization recovery procedure or to perform channel access without losing media synchronization.

[0007] According to another aspect of the embodiments of this application, a channel access method based on NPCA is provided, the method being executed by a first site, the method comprising:

[0008] The first site to perform channel access on the NPCA main channel switches back to the BSS main channel before the third time T0.

[0009] The third time T0 is determined based on the end time of the duration of the first OBSS event or the first OBSS transmission that makes the BSS main channel busy. The first OBSS event or the first OBSS transmission triggers the first station to switch from the BSS main channel to the NPCA main channel.

[0010] According to another aspect of the embodiments of this application, a first device is provided, the first device comprising:

[0011] The processing module is used to determine whether to initiate the media synchronization recovery process or to perform channel access without losing media synchronization when switching from the BSS primary channel to the NPCA primary channel.

[0012] According to another aspect of the embodiments of this application, a first apparatus is provided, the first apparatus performing channel access on the NPCA main channel, the first apparatus comprising:

[0013] The processing module is used to switch back from the NPCA main channel to the BSS main channel before the third time T0;

[0014] The third time T0 is determined based on the end time of the duration of the first OBSS event or the first OBSS transmission that makes the BSS main channel busy. The first OBSS event or the first OBSS transmission triggers the first station to switch from the BSS main channel to the NPCA main channel.

[0015] According to another aspect of the embodiments of this application, a first site is provided, the first site comprising:

[0016] A processor; a transceiver connected to the processor; a memory for storing executable instructions of the processor; wherein the processor is configured to load and execute the executable instructions to implement the NPCA-based channel access method as described above.

[0017] According to another aspect of the embodiments of this application, a computer-readable storage medium is provided, which stores at least one program that is loaded and executed by a processor to implement the NPCA-based channel access method as described in the various aspects above.

[0018] According to another aspect of the embodiments of this application, a first chip is provided, the first chip including programmable logic circuits and / or program instructions, which, when the first chip is run on a first site, is used to implement the NPCA-based channel access method of the above aspects.

[0019] According to another aspect of the embodiments of this application, a second chip is provided, the second chip including programmable logic circuits and / or program instructions, which, when the second chip is run on a first site, is used to implement the NPCA-based channel access method of the above aspects.

[0020] According to another aspect of the embodiments of this application, a computer program product or computer program is provided, which includes computer instructions stored in a computer-readable storage medium, a processor retrieving the computer instructions from the computer-readable storage medium, and the processor executing the computer instructions to implement the NPCA-based channel access method as described in the various aspects above.

[0021] The technical solutions provided in this application embodiment may include the following beneficial effects:

[0022] This method determines whether to initiate a media synchronization recovery procedure or perform channel access without losing media synchronization when the first site switches from the BSS main channel to the NPCA main channel. If it is determined that the media synchronization recovery procedure should be initiated or channel access should be performed under the condition of losing media synchronization, media synchronization on the NPCA main channel can be guaranteed; if it is determined that the media synchronization recovery procedure should not be initiated or channel access should be performed under the condition of not losing media synchronization, it indicates that there is no media synchronization problem on the NPCA main channel. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 shows a schematic diagram of a communication system provided in an exemplary embodiment of this application;

[0025] Figure 2 shows a schematic diagram of the NPCA mechanism provided by the relevant technology;

[0026] Figure 3 shows a flowchart of an exemplary embodiment of the channel access method based on NPCA provided in this application;

[0027] Figure 4 shows a schematic diagram of an OBSS scenario provided by an exemplary embodiment of this application;

[0028] Figure 5 shows a schematic diagram of an NPCA-based channel access method provided in an exemplary embodiment of this application;

[0029] Figure 6 shows a schematic diagram of an NPCA-based channel access method provided in an exemplary embodiment of this application;

[0030] Figure 7 shows a schematic diagram of an NPCA-based channel access method provided in an exemplary embodiment of this application;

[0031] Figure 8 shows a schematic diagram of the format of an extremely reliable operating element provided in an exemplary embodiment of this application;

[0032] Figure 9 illustrates a schematic diagram of the format of the highly reliable operation parameter field provided in an exemplary embodiment of this application;

[0033] Figure 10 shows a schematic diagram of the format of the NPCA operation information field provided in an exemplary embodiment of this application;

[0034] Figure 11 shows a flowchart of an NPCA-based channel access method provided in an exemplary embodiment of this application;

[0035] Figure 12 shows a schematic diagram of an OBSS scenario provided by an exemplary embodiment of this application;

[0036] Figure 13 shows a schematic diagram of an NPCA-based channel access method provided in an exemplary embodiment of this application;

[0037] Figure 14 shows a schematic diagram of an NPCA-based channel access method provided in an exemplary embodiment of this application;

[0038] Figure 15 shows a schematic diagram of an NPCA-based channel access method provided in an exemplary embodiment of this application;

[0039] Figure 16 shows a block diagram of a first apparatus provided in an exemplary embodiment of this application;

[0040] Figure 17 shows a block diagram of a first apparatus provided in an exemplary embodiment of this application;

[0041] Figure 18 shows a schematic diagram of the structure of a first site provided in an exemplary embodiment of this application;

[0042] Figure 19 shows a schematic diagram of the structure of a first site provided in an exemplary embodiment of this application. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be further described in detail below with reference to the accompanying drawings. Exemplary embodiments will be described in detail here, examples of which are illustrated in the accompanying drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0044] The terminology used in this disclosure is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. The singular forms “a,” “the,” and “the” as used in this disclosure and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any and all possible combinations of one or more of the associated listed items.

[0045] It should be understood that although the terms first, second, third, etc., may be used in this disclosure to describe various information, such information should not be limited to these terms. These terms are used only to distinguish information of the same type from one another. For example, without departing from the scope of this disclosure, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Depending on the context, the word "if" as used herein may be interpreted as "when," "when," or "in response to determination."

[0046] It should be understood that in the description of the embodiments of this application, the term "correspondence" may indicate that there is a direct or indirect correspondence between the two, or that there is an association between the two, or that there is a relationship of instruction and being instructed, configuration and being configured, etc.

[0047] In this embodiment of the application, "predefined" 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 terminal devices and network devices). This application does not limit the specific implementation method. For example, predefined can refer to what is defined in the protocol.

[0048] In this application embodiment, "protocol" may refer to standard protocols in the field of communication, such as IEEE 802.11ax protocol, IEEE 802.11be protocol, IEEE 802.11bn protocol, and related protocols applied in future communication systems. This application does not limit this.

[0049] First, a brief introduction to the terms used in the embodiments of this application:

[0050] Primary Channel: This is the channel shared by all member sites in the Basic Service Set (BSS). For example, in the 20MHz BSS, the primary channel is a main 20MHz channel; in the 40MHz BSS, it is a main 20MHz channel; and in the 80MHz BSS, it is a main 40MHz channel.

[0051] Secondary Channel: This is a channel associated with the primary channel, used to create a wider channel than the primary channel. For example, in the basic service set corresponding to 40MHz, the secondary channel is a minor 20MHz channel; in the basic service set corresponding to 80MHz, the secondary channel is a minor 40MHz channel or a 60MHz channel.

[0052] Nonprimary channel: Any one or more secondary channels other than the primary channel in the basic service set of 40MHz, 80MHz, 160MHz or 80+80MHz.

[0053] Sub-channel: In this embodiment, a sub-channel can be understood as a narrow-bandwidth channel within a wide-bandwidth channel. For example, suppose a wide-bandwidth channel corresponds to an 80MHz channel. Optionally, the 80MHz channel can be divided into four 20MHz narrow-bandwidth channels, each of which is a sub-20MHz channel. Alternatively, the 80MHz channel can also be divided into two 40MHz narrow-bandwidth channels, each of which is a sub-40MHz channel.

[0054] Operating Channel: This is the channel used to transmit beacon frames. It can be a collection of multiple channels used during operation, also known as the operational channel. Specific examples include 20MHz, 40MHz, 80MHz, 160MHz, or 320MHz operating channels.

[0055] Operating Channel Width: This refers to the bandwidth of the channels through which a station (STA) can currently receive signals. Specific examples include 20MHz, 40MHz, 80MHz, 160MHz, or 320MHz.

[0056] NPCA Main Channel: A sub-channel within the current operating channel of the basic service set. This sub-channel is used as the main channel when the access point and its associated STA access the system via a non-main channel. For example, assuming the current operating channel bandwidth of the access point is 160MHz, the sub-channels include: a main 80MHz (P80) and a secondary 80MHz (S80). The main 80MHz includes: a main 20MHz (P20), a secondary 20MHz (S20), and a secondary 40MHz (S40, including S20-1 and S20-2). The secondary 80MHz includes S20-3, S20-4, S20-5, and S20-6.

[0057] Optionally, when performing non-main channel access, S20-3 is used as the NPCA main channel P20, S20-4 is used as S20, S20-5 and S20-6 are used as S40, and P80 is used as S80.

[0058] The NPCA primary channel is also called the anchor channel, second primary channel, temporary primary channel, assistant primary channel, auxiliary primary channel, or target subchannel.

[0059] Figure 1 shows a schematic diagram of a communication system 10 provided in an exemplary embodiment of this application. The communication system 10 includes terminals with terminals, terminals with network devices, or access points (APs) with stations (STAs), and this application does not limit the specific examples. This application uses an example where the communication system 10 includes AP 110 and STA 120 for illustration.

[0060] In some scenarios, an AP can also be called an AP STA, meaning that in a sense, an AP is also a type of STA. In other scenarios, a STA can also be called a non-AP STA.

[0061] In some embodiments, a STA may include an AP STA and a non-AP STA. Communication in the communication system can be between an AP and a non-AP STA, between two non-AP STAs, or between a STA and a peer STA (remote site). A peer STA can refer to a device communicating with the STA from the other end; for example, a peer STA may be an AP or a non-AP STA. Exemplarily, there are two communication scenarios between a STA and an AP: uplink communication and downlink communication. Uplink communication involves the STA sending signals to the AP; downlink communication involves the AP sending signals to the STA. An AP acts as a bridge connecting wired and wireless networks, primarily connecting various wireless network clients together and then connecting the wireless network to the Ethernet. An AP device can be a terminal device (such as a mobile phone) or a network device (such as a router) with a Wireless Fidelity (WiFi) chip.

[0062] In this application's embodiments, the STA can be a device with wireless transceiver capabilities, such as a device supporting the 802.11 series of protocols, capable of communicating with an AP or other STAs. For example, an STA is any user communication device that allows a user to communicate with an AP and subsequently with a WLAN. STAs can be, 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.

[0063] In this application embodiment, the STA can also be a device that provides voice / data / image connectivity to a user. For example, it can be a handheld device, in-vehicle device, home device, home appliance, gaming device, etc., that has wireless connectivity or is 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 evolved Public Land Mobile 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.

[0064] 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.

[0065] 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 of 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).

[0066] Furthermore, in this embodiment, STA can also be an in-vehicle communication device in the vehicle-to-everything (V2X) system or the vehicle itself. The communication methods in the 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.

[0067] It should be understood that the role of a STA in a communication system is not absolute. For example, in some scenarios, when a mobile phone connects to a router, it acts as a non-AP STA; when the phone serves as a hotspot for other mobile phones, it acts as an AP. APs and non-AP STAs can be devices used in vehicle-to-everything (V2X) networks, IoT nodes and sensors in the Internet of Things (IoT), smart cameras, smart remote controls, smart water and electricity meters in smart homes, and sensors in smart cities.

[0068] In some embodiments, the non-AP STA may support, but is not limited to, the 802.11be standard. The non-AP STA may also support various current and future 802.11 family of wireless LAN standards, such as 802.11bn, 802.11ax, 802.11ac, 802.11n, 802.11g, 802.11b, and 802.11a.

[0069] In some embodiments, 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 802.11bn, 802.11ax, 802.11ac, 802.11n, 802.11g, 802.11b, and 802.11a.

[0070] In this embodiment, the STA can be a mobile phone, tablet computer, computer, virtual reality device, augmented reality device, communication device in industrial control, set-top box, communication device in autonomous driving, vehicle communication device, communication device in telemedicine, communication device in smart grid, communication device in transportation safety, communication device in smart city, or communication device in smart home, or wireless communication chip, etc., that supports WLAN / Wi-Fi technology. WLAN technology can support frequency bands including but not limited to: low frequency bands (2.4GHz, 5GHz, 6GHz) and high frequency bands (45GHz, 60GHz).

[0071] One or more links exist between a site and an access point. In some embodiments, the site and access point support multi-band communication, for example, simultaneously communicating on the 2.4 GHz, 5 GHz, 6 GHz, 45 GHz, and 60 GHz bands, or simultaneously communicating on different channels within the same (or different) bands, improving communication throughput and / or reliability between devices. Such devices are commonly referred to as multi-band devices, and may also be called multi-link devices (MLDs), sometimes also called multi-link entities or multi-band entities. A multi-link device can be an access point device or a site device. If the multi-link device is an access point device, it includes one or more access points (APs); if the multi-link device is a site device, it includes one or more non-AP STAs. A multi-link device including one or more APs can also be called an AP, and a multi-link device including one or more non-AP STAs can also be called a Non-AP. In this embodiment, a Non-AP can be called a STA.

[0072] In this embodiment of the application, an AP may include multiple APs, and a Non-AP may include multiple STAs. Multiple links may be formed between the multiple APs in the AP and the multiple STAs in the Non-AP. Data communication may be performed between corresponding APs in the AP and corresponding STAs in the Non-AP through the corresponding links.

[0073] An AP MLD can include one or more APs; that is, an AP MLD's associated STAs include one or more APs. A non-AP MLD can include one or more non-AP STAs; that is, a non-AP MLD's associated STAs include one or more non-AP STAs. One or more links can be formed between AP MLDs and non-AP MLDs, allowing communication between APs associated with an AP MLD and between non-AP STAs associated with a non-AP MLD. One or more peer-to-peer (P2P) links can also be formed between non-AP MLDs, allowing communication between non-AP STAs associated with two different non-AP MLDs. Similarly, one or more P2P links can be formed between AP MLDs, allowing communication between APs associated with two different AP MLDs.

[0074] A Basic Service Set (BSS) is the fundamental topology in WLAN / Wi-Fi communication. The communication devices constituting a BSS include one Access Point (AP) and several non-AP STAs (Standard Target Units). After joining the AP's radio domain, each non-AP STA establishes an association with the AP. Associated non-AP STAs and the AP can transmit data, and non-AP STAs within the same BSS can exchange data through the AP.

[0075] In the embodiments of this application, both STA and AP support the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard, but are not limited to the IEEE 802.11 standard.

[0076] The following section describes the relevant technologies involved in the embodiments of this application:

[0077] • Non-Primary Channel Access (NPCA) mechanism:

[0078] Figure 2 shows a schematic diagram of the non-primary channel access mechanism provided by the relevant technology.

[0079] The NPCA operating mode allows STAs to access secondary channels when the primary channel is busy due to Overlapping Basic Service Set (OBSS) traffic or other conditions. In particular, the NPCA operating mode does not assume that STAs can simultaneously detect or decode frames and obtain Network Allocation Vector (NAV) information on both the primary and secondary channels. Also, a BSS can only have one NPCA primary channel. When the BSS's primary channel is busy due to OBSS traffic or other conditions, STAs can compete for the channel on the NPCA primary channel.

[0080] As shown in Figure 2, the STA operates with a bandwidth of 80MHz. When the STA detects OBSS interference, i.e., 20MHz (or 40MHz) inter-PHY Protocol Data Unit (inter-PPDU), it can compete for the channel on the other 60MHz (or 40MHz) secondary channel. Once it wins the transmission opportunity (TXOP), it can transmit. When the STA detects 20MHz inter-PPDU, it can compete for the channel on the other 60MHz secondary channel. Once it wins the TXOP, it can transmit.

[0081] • Conditions required to switch to the NPCA main channel for NPCA operations:

[0082] When the BSS to which the STA belongs enables NPCA operation and meets either of the following conditions a) or b), the STA can switch to the NPCA main channel to perform NPCA operation:

[0083] a) The STA receives a PPDU on the BSS main channel, and / or receives a PHY-RXSTART.indication primitive for a High Efficiency / Extremely High Throughput / Ultra High Reliability (HE / EHT / UHR) PPDU, and all of the following conditions are met:

[0084] a. Based on the procedures defined in the relevant standards (BSS intra-BSS and cross-BSS PPDU classification), the STA classifies this PPDU as an inter-BSS PPDU;

[0085] b. The duration of the PPDU is greater than the value shown in the minimum duration threshold field of the most recently received or sent NPCA, which corresponds to the BSS where the site is located;

[0086] c. The 20 / 40 / 80 / 160MHz channels occupied by the PPDU are identified by the STA based on the bandwidth field in the physical preamble of the PPDU and the channel allocation of the corresponding frequency band, and the channels occupied by the PPDU do not overlap with the NPCA main channel.

[0087] b) The STA receives a PPDU carrying a control frame and / or a PPDU carrying a response frame corresponding to a control frame exchange on the BSS main channel, and all of the following conditions are met:

[0088] a. Based on the procedures defined in the relevant standards (BSS intra-BSS and cross-BSS PPDU classification), the STA classifies this PPDU as an inter-BSS PPDU;

[0089] b. The duration of the transmission opportunity (TXOP) determined from the duration field of the received frame is greater than the value of the minimum duration threshold field of the most recently received or transmitted NPCA corresponding to its BSS.

[0090] c. The 20 / 40 / 80 / 160MHz channel occupied by the received PPDU is determined by the STA according to the channel allocation of the corresponding frequency band and the PPDU bandwidth indicated in the received PPDU, or obtained from the RXVECTOR parameter CH_BANDWIDTH_IN_NON_HT of the received PPDU, and the bandwidth of the PPDU station does not overlap with the NPCA main channel.

[0091] i. If the control frame is a Request To Send (RTS) frame in a non-High Throughput (HT) (repeated) PPDU, then it includes a bandwidth signaling that indicates the PPDU bandwidth as 20MHz, 40MHz, 80MHz, or 160MHz.

[0092] ii. Determine the channel occupied by the CTS frame received in a non-HT (repeated) PPDU by examining the request to send RTS frame or multi-user RTS frame that elicits a Clear To Send (CTS) frame response.

[0093] The NPCA mechanism allows stations to switch to the NPCA operating channel to perform data transmission when the primary channel is busy due to OBSS traffic or other conditions. Since access point and non-access point stations originally operated on their respective BSS operating channels and could not perform monitoring or idle channel assessment on the NPCA operating channel, there is a problem of media synchronization that cannot be guaranteed when access point and non-access point stations switch to the NPCA operating channel simultaneously.

[0094] To address the aforementioned problems, this application provides a channel access method based on NPCA. Figure 3 shows a flowchart of an exemplary embodiment of the channel access method based on NPCA provided in this application. The method is executed by a first site and includes:

[0095] Step 310: In the case of switching from the BSS primary channel to the NPCA primary channel, determine whether to initiate the media synchronization recovery procedure or to perform channel access without losing media synchronization.

[0096] The determination of whether to perform channel access under the condition of not losing media synchronization corresponds to the determination of whether to initiate the media synchronization recovery procedure. That is, if the first site determines that channel access will be performed under the condition of not losing media synchronization, the first site determines not to initiate the media synchronization recovery procedure; if the first site determines that channel access will be performed under the condition of losing media synchronization, the first site determines to initiate the media synchronization recovery procedure. The media synchronization recovery procedure can also be simply referred to as the media recovery procedure, and this application embodiment does not limit it to that.

[0097] In some embodiments, the first site is an access point (AP) and the second site is a non-access point site (non-AP STA); or, the first site is a non-access point site (non-AP STA) and the second site is an access point (AP). This application does not limit this specific configuration. A non-AP STA can be simply referred to as an STA. An AP that supports NPCA operation can be called an NPCA AP, and a STA that supports NPCA operation (non-AP STA) can be called an NPCA STA.

[0098] Due to interference from OBSS events, both the first and second stations switch from the BSS main channel to the NPCA main channel. The first station switches to the NPCA main channel due to the triggering of the first OBSS event, and the second station switches to the NPCA main channel due to the triggering of the second OBSS event. The first and second OBSS events may be the same or different. This application does not limit this, but it is usually described by assuming that the first and second OBSS events are the same.

[0099] Alternatively, an OBSS event can also be understood as an OBSS transmission. Triggering an OBSS event (OBSS activity) or OBSS transmission (OBSS transmission) has the same meaning, which refers to detecting or receiving an OBSS PPDU (i.e., a PPDU transmitted in OBSS). In this application embodiment, the OBSS event is usually used as an example for explanation.

[0100] The first OBSS event that triggers the first site to switch from the BSS main channel to the NPA main channel can also be understood as the first OBSS PPDU that triggers the first site to switch from the BSS main channel to the NPA main channel; the second OBSS event that triggers the second site to switch from the BSS main channel to the NPA main channel can also be understood as the second OBSS PPDU that triggers the second site to switch from the BSS main channel to the NPA main channel.

[0101] Figure 4 shows a schematic diagram of an OBSS scenario provided by an exemplary embodiment of this application.

[0102] In BSS1, STA1 is associated with AP1. OBSS1 (BSS2) is the OBSS of BSS1, and STA2 corresponding to OBSS1 is associated with AP2.

[0103] Figure 5 shows a schematic diagram of an NPCA-based channel access method provided in an exemplary embodiment of this application.

[0104] BSS1 operates with a bandwidth of 80MHz, as shown in Figure 4. AP1 and STA1 corresponding to this BSS support NPCA operation. The NPCA primary channel is located on the third 20MHz secondary channel. Furthermore, there exists another BSS2, which is the OBSS of BSS1 (i.e., OBSS1), using the same primary channel as BSS1 or having its operation channel covering BSS1's primary channel. AP1 can publish NPCA operation information by carrying Ultra-High Reliability (UHR) operation elements in its transmitted management frames (e.g., beacon frames, probe response frames, association response frames, reassociation response frames). The management frames are transmitted before the data PPDU from BSS1.

[0105] An AP that supports NPCA operation can be called an NPCA AP, and a STA (non-AP STA) that supports NPCA operation can be called an NPCA STA. An NPCA AP can carry a first handover delay field and a first handover return delay field in the management frame, quality of service data frame, or control frame it transmits. The first handover delay field indicates the NPCA AP's NPCA handover delay (the delay of switching from the BSS primary channel to the NPCA primary channel), and the first handover return delay field indicates the NPCA AP's NPCA handover return delay (the delay of switching from the NPCA primary channel back to the BSS primary channel).

[0106] NPCASTA may carry a second handover delay field and a second handover back delay field in the management frame, quality of service data frame or control frame it transmits. The second handover delay field is used to indicate the NPCA handover delay of the NPCA STA (the delay of switching from the BSS primary channel to the NPCA primary channel), and the second handover back delay field is used to indicate the NPCA handover back delay of the NPCA STA (the delay of switching from the NPCA primary channel back to the BSS primary channel).

[0107] If AP1 or STA1, while operating on the BSS primary channel, does not perform Clear Channel Assessment (CCA) on the NPCA primary channel and cannot obtain channel idle / busy or transmission information on the NPCA primary channel, it can be assumed that AP1 or STA1 lost media synchronization on the NPCA primary channel before switching to the NPCA primary channel (including during the switch from the BSS primary channel to the NPCA primary channel).

[0108] AP1 and STA1 in BSS1 perform frame exchange, and the data PPDUs transmitted during the frame exchange cover both the BSS main channel and the NPCA main channel, as shown in Figure 5. The data PPDUs transmitted between AP1 and STA1 occupy 80MHz of bandwidth. After the frame exchange ends, AP1 and / or STA1 detects an OBSS PPDU (i.e., the data PPDU transmitted between AP2 and STA2 in BSS2), which occupies 40MHz of bandwidth. When the NPCA handover conditions are met (e.g., the duration of the OBSS PPDU is greater than the value indicated by the NPCA minimum duration threshold field, which is the NPCA minimum duration threshold field corresponding to BSS1 most recently sent by AP1 or most recently received by STA1), AP1 or STA1 switches to the NPCA main channel. In the case of AP1 or STA1 switching to the NPCA main channel, AP1 or STA1 can determine whether to initiate the media synchronization recovery procedure according to one of the following preset rules.

[0109] 1.1 Preset Rules:

[0110] In some embodiments, when switching from the BSS primary channel to the NPCA primary channel, it is determined whether to initiate a media synchronization recovery procedure or to perform channel access without losing media synchronization based on preset rules; the preset rules are related to at least one of the following factors:

[0111] Whether the first duration is less than or equal to the first threshold; whether the NPCA main channel is detected to be idle after switching to the NPCA main channel; whether the first PPDU is detected or received on the NPCA main channel after switching to the NPCA main channel;

[0112] The first duration is the duration between the first time point and the second time point. The first time point is determined based on the channel access operation or channel idle / busy status before the first site switches from the BSS main channel to the NPCA main channel. The second time point is the start time of the first site switching to the NPCA main channel.

[0113] For example, in Figure 5, the first time S1 is the end time of frame switching performed by the first station before switching from the BSS main channel to the NPA main channel, and the second time S2 is the start time of the first station switching to the NPA main channel.

[0114] In some embodiments, determining whether to initiate a media synchronization recovery process or to perform channel access without losing media synchronization based on preset rules includes at least one of the following:

[0115] (1) If the first duration is less than or equal to the first threshold, determine that the first site does not initiate the media synchronization recovery process or performs channel access in accordance with the condition of not losing media synchronization;

[0116] (2) If the first duration is less than or equal to the first threshold, and the first site detects that the NPCA main channel is idle based on the OFDM ED threshold after switching to the NPCA main channel, it is determined that the first site will not start the media synchronization recovery process or will perform channel access in accordance with the condition of not losing media synchronization.

[0117] (3) If the first duration is less than or equal to the first threshold, and the first site detects that the NPCA main channel is idle within a predetermined time interval after switching to the NPCA main channel, it is determined that the first site will not start the media synchronization recovery process or will perform channel access in accordance with the condition of not losing media synchronization.

[0118] (4) If the first duration is less than or equal to the first threshold, and the first station detects or receives the first PPDU on the NPCA main channel within a predetermined time interval after switching to the NPCA main channel, it is determined that the first station will not start the media synchronization recovery process or will perform channel access in accordance with the condition of not losing media synchronization.

[0119] (5) If the first duration is less than or equal to the first threshold, and the first site detects that the NPCA main channel is idle after switching to the NPCA main channel, it is determined that the first site will not start the media synchronization recovery process or will perform channel access in accordance with the condition of not losing media synchronization.

[0120] (6) If the first duration is less than or equal to the first threshold, and the first site detects that the NPCA main channel is idle within a predetermined time interval after switching to the NPCA main channel, based on the NPCA media synchronization OFDM ED threshold, it is determined that the first site will not start the media synchronization recovery process or will perform channel access in accordance with the condition of not losing media synchronization.

[0121] (7) If the first duration is less than or equal to the first threshold, and the first station detects or receives the first PPDU on the NPCA main channel within a predetermined time interval after switching to the NPCA main channel, it is determined that the first station will not initiate the media synchronization recovery process or will perform channel access in accordance with the condition of not losing media synchronization.

[0122] (8) In the case where the first duration is greater than the first threshold; or in the case where the first station does not detect the NPCA main channel being idle based on the OFDM ED threshold after switching to the NPCA main channel; or in the case where the first station does not detect the NPCA main channel being idle based on the OFDM ED threshold within a predetermined time interval after switching to the NPCA main channel; or in the case where the first station does not detect or receive the first PPDU on the NPCA main channel within a predetermined time interval after switching to the NPCA main channel; or in the case where the first station does not detect the NPCA main channel being idle based on the NPCA media synchronization OFDM ED threshold after switching to the NPCA main channel; or in the case where the first station does not detect or receive the first PPDU on the NPCA main channel within a predetermined time interval ... If the ED threshold does not detect that the NPCA main channel is idle, and no PPDU is detected or received on the NPCA main channel; or if, within a predetermined time interval after switching to the NPCA main channel, the first site determines that it should initiate the media synchronization recovery process or perform channel access as if media synchronization has been lost.

[0123] Regarding (1), based on whether the first duration is less than or equal to the first threshold, it is determined whether to initiate the media synchronization recovery process or whether to perform channel access in accordance with the condition of not losing media synchronization.

[0124] In some embodiments, the first threshold is a media synchronization duration threshold.

[0125] If the first duration is less than or equal to the media synchronization duration threshold, it is determined that the first site will not initiate the media synchronization recovery process. This can also be understood as the first site performing channel access under the condition of not losing media synchronization.

[0126] The first time is the time when the frame exchange performed by the first station ends before the first station switches from the BSS main channel to the NPCA main channel, and the operation bandwidth of this frame exchange covers the NPCA main channel.

[0127] For (2), (3), and (4), based on whether the first duration is less than or equal to the first threshold and the detected channel conditions, it is determined whether to initiate the media synchronization recovery process or whether to perform channel access under the condition of not losing media synchronization. Additionally, the OFDM ED threshold (dot11OFDMEDThreshold) is used to detect whether the channel is idle.

[0128] In some embodiments, NPCA main channel idle is detected based on at least one of the following thresholds:

[0129] Orthogonal Frequency Division Multiplexing Energy Detection (OFDM ED) threshold; NPCA media synchronization OFDM ED threshold.

[0130] The OFDM ED threshold is a threshold used for energy detection to determine whether a channel is idle, i.e., whether other stations are using the channel. When the received signal energy is less than or equal to this threshold, the channel is considered idle; when the received signal energy is greater than this threshold, the channel is considered busy.

[0131] Optionally, the NPCA media synchronization OFDM ED threshold is less than or equal to the OFDM ED threshold.

[0132] When the requirement for determining the idle status of the NPCA main channel is high, the NPCA medium synchronization OFDM ED threshold is used; when the requirement for determining the idle status of the NPCA main channel is low, the OFDM ED threshold is used.

[0133] Regarding (2), if the first duration is less than or equal to the media synchronization duration threshold, and the first site detects that the NPCA main channel is idle based on the OFDM ED threshold after switching to the NPCA main channel, it is determined that the first site will not start the media synchronization recovery process or will perform channel access in accordance with the condition of not losing media synchronization.

[0134] Optionally, the first time is the time when the frame exchange performed by the first station ends before the first station switches from the BSS main channel to the NPCA main channel, and the operating bandwidth of the frame exchange covers the NPCA main channel.

[0135] Regarding (3), if the first duration is less than or equal to the first threshold, and the first station detects that the NPCA main channel is idle within a predetermined time interval after switching to the NPCA main channel, it is determined that the first station will not start the media synchronization recovery process or will perform channel access in accordance with the condition of not losing media synchronization.

[0136] In some embodiments, determining whether the NPCA main channel is detected to be idle after switching to the NPCA main channel includes: determining whether the NPCA main channel is detected to be idle during a predetermined time interval after switching to the NPCA main channel.

[0137] For example, the predetermined time interval is the channel detection time (aCCAtime) in the relevant standard, which indicates the time required for a station to perform CCA. The predetermined time interval can also be 0, the Short Inter-Frame Space (SIFS), or other intervals.

[0138] During the channel detection period after the first station switches to the NPCA main channel, if the signal energy received by the first station is less than or equal to the OFDM ED threshold of the BSS main channel (e.g., -62 dBmW) and no PPDU start signal is detected, the NPCA main channel can be considered idle.

[0139] Regarding (4), if the first duration is less than or equal to the first threshold, and the first station detects or receives the first PPDU on the NPCA main channel within a predetermined time interval after switching to the NPCA main channel, it is determined that the first station will not initiate the media synchronization recovery process or will perform channel access in accordance with the condition of not losing media synchronization.

[0140] In some embodiments, detecting or receiving a first PPDU includes at least one of the following:

[0141] Received a Medium Access Control Protocol Data Unit (MPDU); detected that the Transmission Opportunity Duration parameter (TXOP_DURATION) is not an unspecified PPDU.

[0142] The transmission opportunity duration parameter is a parameter in the receive vector (RXVECTOR) used to represent the duration of a transmission opportunity; "not unspecified" means that the transmission opportunity duration parameter has been explicitly specified.

[0143] For (5), (6), and (7), based on whether the first duration is less than or equal to the first threshold and the detected channel conditions, it is determined whether to initiate the media synchronization recovery process or whether to perform channel access under the condition of not losing media synchronization. The NPCA media synchronization OFDM ED threshold (dot11NPCAMSOFDMEDthreshold) is used to detect whether the channel is idle.

[0144] Regarding (5), if the first duration is less than or equal to the first threshold, and the first site detects that the NPCA main channel is idle after switching to the NPCA main channel, it is determined that the first site will not start the media synchronization recovery process or will perform channel access in accordance with the condition of not losing media synchronization.

[0145] Optionally, the first time is the time when the frame exchange performed by the first station ends before the first station switches from the BSS main channel to the NPCA main channel, and the operation bandwidth corresponding to the frame exchange covers the NPCA main channel.

[0146] The NPCA Media Synchronization OFDM ED threshold is a threshold used for energy detection to determine whether the NPCA main channel is idle. When the signal energy received by the first station is less than or equal to this threshold, the NPCA main channel is considered idle; when the received signal energy is greater than this threshold, the NPCA main channel is considered busy. The NPCA Media Synchronization OFDM ED threshold is obtained from the NPCA Media Synchronization OFDM ED threshold field most recently sent or received by the first station.

[0147] Regarding (6), if the first duration is less than or equal to the first threshold, and the first site detects that the NPCA main channel is idle within a predetermined time interval after switching to the NPCA main channel, it is determined that the first site will not start the media synchronization recovery process or will perform channel access in accordance with the condition of not losing media synchronization.

[0148] For details on the specific implementation of the predetermined time interval, please refer to (3), which will not be repeated here.

[0149] During the channel detection period after the first station switches to the NPCA main channel, if the signal energy received by the first station is less than or equal to the NPCA medium synchronization OFDM ED threshold and no PPDU start signal is detected, the NPCA main channel can be considered idle.

[0150] For (7), if the first duration is less than or equal to the first threshold, and the first station detects or receives the first PPDU on the NPCA main channel within a predetermined time interval after switching to the NPCA main channel, it is determined that the first station will not initiate the media synchronization recovery process or will perform channel access in accordance with the condition of not losing media synchronization.

[0151] For specific implementation details of detecting or receiving the first PPDU, please refer to (4), which will not be repeated here.

[0152] Regarding (8), if any of the conditions are met, the first site is determined to initiate the media synchronization recovery process or perform channel access according to the case of lost media synchronization. The specific combination and implementation of each condition in the embodiments of this application are not limited.

[0153] For example, if the first duration exceeds the first threshold, determine whether the first site initiates the media synchronization recovery process or performs channel access as if media synchronization has been lost.

[0154] For example, if the first duration is greater than the first threshold, or if the first site does not detect that the NPCA main channel is idle after switching to the NPCA main channel based on the OFDM ED threshold, it is determined that the first site should initiate the media synchronization recovery process or perform channel access as if media synchronization has been lost.

[0155] For example, if the first duration is less than or equal to the first threshold, or if the first site does not detect that the NPCA main channel is idle within a predetermined time interval after switching to the NPCA main channel, based on the OFDM ED threshold, it is determined that the first site initiates the media synchronization recovery procedure or performs channel access as if media synchronization has been lost.

[0156] For example, if the first duration is less than or equal to the first threshold, and the first site does not detect or receive the first PPDU on the NPCA main channel within a predetermined time interval after switching to the NPCA main channel, it is determined that the first site initiates the media synchronization recovery procedure or performs channel access as if media synchronization has been lost.

[0157] For example, if the first duration is less than or equal to the first threshold, and the first site does not detect that the NPCA main channel is idle after switching to the NPCA main channel based on the NPCA media synchronization OFDM ED threshold, it is determined that the first site should initiate the media synchronization recovery process or perform channel access as if media synchronization has been lost.

[0158] For example, if the first duration is less than or equal to the first threshold, and the first site does not detect that the NPCA main channel is idle within a predetermined time interval after switching to the NPCA main channel, based on the NPCA media synchronization OFDM ED threshold, it is determined that the first site should initiate the media synchronization recovery process or perform channel access as if media synchronization has been lost.

[0159] For example, if the first duration is less than or equal to the first threshold, and the first site does not detect or receive the first PPDU on the NPCA main channel within a predetermined time interval after switching to the NPCA main channel, it is determined that the first site initiates the media synchronization recovery procedure or performs channel access as if media synchronization has been lost.

[0160] For example, if the first duration is less than or equal to the first threshold, and the first site does not detect that the NPCA main channel is idle within a predetermined time interval after switching to the NPCA main channel based on the OFDM ED threshold, and does not detect or receive the first PPDU on the NPCA main channel, it is determined that the first site initiates the media synchronization recovery procedure or performs channel access according to the case of lost media synchronization.

[0161] For example, if the first duration is less than or equal to the first threshold, and the first site does not detect that the NPCA main channel is idle within a predetermined time interval after switching to the NPCA main channel, based on the NPCA media synchronization OFDM ED threshold, and does not detect or receive the first PPDU on the NPCA main channel, it is determined that the first site initiates the media synchronization recovery process or performs channel access as if media synchronization has been lost.

[0162] By determining whether to initiate the media synchronization recovery process based on different types of preset rules, the appropriate preset rules can be flexibly selected according to different scenario requirements, thus expanding the applicability of the NPCA-based channel access method.

[0163] 1.2 First Immediate Response:

[0164] In some embodiments, the first time includes at least one of the following:

[0165] 1) The time when the first station finishes performing frame exchange with any station, and the operation bandwidth corresponding to the frame exchange covers the NPCA main channel;

[0166] 2) The end time of OBSS PPDU transmission carrying control frames, or the end time of the TXOP where the OBSS PPDU is located, OBSS PPDU carrying control frames occupies the NPCA main channel;

[0167] 3) The expiration or clearing time of the inter-BSS network allocation vector (Inter-BSS NAV) generated by the previous OBSS PPDU transmission. The previous OBSS PPDU occupies the NPCA main channel. The previous OBSS PPDU is the most recent OBSS PPDU detected before the handover.

[0168] 4) The expiration or clearing time of the internal BSS NAV generated by the transmission of the previous internal BSS PPDU. The previous internal BSS PPDU occupies the NPCA main channel. The previous internal BSS PPDU is the most recent internal BSS PPDU detected before the handover.

[0169] For the specific implementation details of 1), please refer to (1) to (8) in the preset rules of 1.1, which will not be repeated here.

[0170] Regarding 2), Figure 6 shows a schematic diagram of an NPCA-based channel access method provided in an exemplary embodiment of this application.

[0171] BSS1 operates with a bandwidth of 80MHz, as shown in Figure 6. AP1 and STA1 corresponding to BSS1 support NPCA operation. The NPCA primary channel is located on the third 20MHz secondary channel. Furthermore, there exists another BSS2, which is the OBSS of BSS1 (i.e., OBSS1), using the same primary channel as BSS1 or having its operating channel cover the primary channel of BSS1.

[0172] AP1 and / or STA1 detect OBSS PPDUs carrying control frames and OBSS PPDUs carrying response frames. The OBSS PPDU carrying the control frame occupies 80MHz of bandwidth, and the OBSS PPDU carrying the response frame occupies 40MHz of bandwidth (i.e., it does not occupy the NPCA main channel of BSS1). When the NPCA handover conditions are met, AP1 and / or STA1 switch to the NPCA main channel.

[0173] Taking the implementation of 2) and (6) as an example, if the duration between the end time of the OBSS PPDU transmission carrying the control frame (first time S1) and the second time S2 is less than or equal to the first threshold, and if the first station detects that the NPCA main channel is idle within a predetermined time interval after switching to the NPCA main channel, the first station determines that it will not start the media synchronization recovery process.

[0174] The predetermined time interval is the channel detection time (aCCAtime) in the relevant standard. During the channel detection time after the first station switches to the NPCA main channel, if the signal energy received by the first station is less than or equal to the NPCA medium synchronization OFDM ED threshold and no PPDU start signal is detected, the NPCA main channel can be considered to be idle.

[0175] 2) It can also be implemented in combination with (1) to (5), (7) and (8) in the preset rules of 1.1, and this application does not limit this.

[0176] For 3) and 4), cross-BSS NAV and internal BSS NAV are two types of NAV timers used to manage channel access.

[0177] Inter-BSS NAV is used to manage frame transmission between different BSSs. If the BSS color in a received PPDU differs from the BSS color of the associated AP, the STA will treat the PPDU as an OBSS PPDU and set the value of the inter-BSS NAV timer. When the inter-BSS NAV timer counts down, it is the expiration or reset time of the inter-BSS NAV.

[0178] The internal BSS NAV is used to manage frame transmissions within the same BSS. If the BSS color in a received PPDU is the same as the BSS color of the associated AP, the STA will treat that PPDU as an internal BSS PPDU and set the value of the internal BSS NAV timer. When the internal BSS NAV timer counts down to zero, it is the expiration or reset time of the internal BSS NAV.

[0179] Cross-BSS NAV and internal BSS NAV can also be collectively referred to as basic NAV, which is an NAV timer that does not distinguish between frame transmissions between different BSSs or within the same BSS.

[0180] Regarding 3), Figure 7 shows a schematic diagram of an NPCA-based channel access method provided in an exemplary embodiment of this application.

[0181] BSS1 operates with a bandwidth of 80MHz, as shown in Figure 7. AP1 and STA1 corresponding to BSS1 support NPCA operation. The NPCA primary channel is located on the third 20MHz secondary channel. Furthermore, there exists another BSS2, which is the OBSS of BSS1 (i.e., OBSS1), using the same primary channel as BSS1 or having its operating channel cover the primary channel of BSS1.

[0182] AP1 or STA1, located in BSS1, detects an OBSS PPDU transmission (the previous OBSS PPDU transmission). This OBSS PPDU transmission occupies 80MHz and causes AP1 or STA1 to set the corresponding cross-BSS NAV (or basic NAV; this explanation only uses the cross-BSS NAV as an example). When the cross-BSS NAV expires or is cleared, AP1 and / or STA1 detects another OBSS PPDU transmission (i.e., the PPDU transmitted between AP2 and STA2 in the diagram). When the NPCA handover conditions are met, AP1 or STA1 switches to the NPCA main channel.

[0183] Taking the implementation of 3) and (6) as an example, when the time between the expiration or clearing time of the cross-BSS NAV (first time S1) and the second time S2 is less than or equal to the first threshold, and the first station detects that the NPCA main channel is idle within a predetermined time interval after switching to the NPCA main channel, it is determined that the first station will not start the media synchronization recovery process.

[0184] The predetermined time interval is the channel detection time (aCCAtime) in the relevant standard. During the channel detection time after the first station switches to the NPCA main channel, if the signal energy received by the first station is less than or equal to the NPCA medium synchronization OFDM ED threshold and no PPDU start signal is detected, the NPCA main channel can be considered to be idle.

[0185] 3) It can also be implemented in combination with (1) to (5), (7) and (8) in the preset rules of 1.1, and this application does not limit this.

[0186] Regarding 4), AP1 or STA1 in BSS1 detects a BSS internal PPDU transmission (the previous BSS internal PPDU transmission). This BSS internal PPDU transmission occupies 80MHz and causes AP1 or STA1 to set the corresponding internal BSS NAV. When the internal BSS NAV expires or is cleared, AP1 and / or STA1 detects an OBSS PPDU transmission. When the NPCA handover conditions are met, AP1 or STA1 switches to the NPCA main channel.

[0187] Taking the implementation of 4) and (6) as an example, when the time between the expiration or clearing time (first time) of the internal BSS NAV and the second time is less than or equal to the first threshold, and the first site detects that the NPCA main channel is idle within a predetermined time interval after switching to the NPCA main channel, it is determined that the first site will not start the media synchronization recovery process.

[0188] The predetermined time interval is the channel detection time (aCCAtime) in the relevant standard. During the channel detection time after the first station switches to the NPCA main channel, if the signal energy received by the first station is less than or equal to the NPCA medium synchronization OFDM ED threshold and no PPDU start signal is detected, the NPCA main channel can be considered to be idle.

[0189] 4) It can also be implemented in combination with (1) to (5), (7) and (8) in the preset rules of 1.1, and this application does not limit this.

[0190] 1.3 First Threshold:

[0191] In some embodiments, the first threshold is the minimum PPDU duration carrying control frames or data frames, or the sum of the minimum PPDU duration carrying control frames or data frames and a preset frame spacing.

[0192] For example, the minimum PPDU duration carrying control frames or data frames can be set to 72 microseconds. 72 microseconds is chosen to cover the PPDU length of RTS frames, CTS frames, or acknowledgment frames using a data rate of 6 MB / s and a non-HT or non-HT repeating PPDU format, as well as the PPDU length of most block acknowledgment frames.

[0193] By way of example and not limitation, the preset inter-frame spacing includes at least one of the following: Short Inter-Frame Space (SIFS), Point Coordination Function Inter-Frame Space (PIFS), and Arbitration Inter-Frame Space (AIFS).

[0194] For example, the preset frame interval is SIFS, and the first threshold is the sum of 72 microseconds and SIFS.

[0195] In some embodiments, the first threshold is carried in the NPCA media synchronization threshold field, which is carried in the first frame sent by the second station.

[0196] 1.4 Channel Access Rules:

[0197] If, after the first site switches to the NPCA main channel, it is determined that the first site has not lost media synchronization on the NPCA main channel, or it is determined that the media synchronization recovery process will not be initiated, then one or more of the following channel access rules shall be adopted.

[0198] Taking STA as the first station as an example, when STA is ready to transmit on the NPCA main channel, STA can initiate TXOP on the NPCA main channel, but the following rules apply:

[0199] a. Each time the STA switches to the NPCA main channel, the NPCA contention window [Access Category] (CW_NPCA[AC]) is initialized to a predetermined value, and a new initial value is randomly selected between 0 and CW_NPCA[AC] as the value of the backoff counter.

[0200] b. Set the queued service resource [access class] (Queued Service Resource_NPCA[AC], QSRC_NPCA[AC]) of NPCA to 0.

[0201] c. If the STA is a non-AP STA and the associated AP has prohibited untriggered uplink transmissions on the NPCA main channel, then the non-AP STA must not initiate a TXOP on the NPCA main channel.

[0202] d.STA initiates frame switching on the NPCA main channel using the NPCA initial control frame, using non-HT PPDU or non-HT repeated PPDU format, at a rate of 6MB / s, 12MB / s, or 24MB / s.

[0203] If the first site switches to the NPCA main channel and initiates a media synchronization recovery process due to lost media synchronization, in addition to following the above channel access rules (i.e., a to d) regarding the channel access rules of the NCPA main channel, a medium synchronization delay (MediumSyncDelay) timer will also be started.

[0204] Taking the first station as STA as an example, the media synchronization delay timer is a timer shared by all EDCA function modules (EDCAF) within STA, and its value is set to the media synchronization delay timer duration (dot11MSDTimerDuration).

[0205] The media synchronization delay timer will be reset to zero when any of the following events occur: the STA receives an MPDU; or the STA detects that the transmission opportunity duration parameter (TXOP_DURATION) is not an unspecified PPDU.

[0206] For STAs that can obtain TXOP, when their media synchronization delay timer is non-zero, the media synchronization delay OFDM ED threshold (dot11MSDOFDMEDthreshold) or NPCA media synchronization OFDM ED threshold (dot11NPCAMSOFDMEDthreshold) should be used instead of the OFDM ED threshold (dot11OFDMEDThreshold) to detect the channel idle / busy state in the primary 20MHz channel.

[0207] If the STA obtains a TXOP while the media synchronization delay timer is non-zero, the STA should do the following: After the media synchronization delay timer begins its countdown, it should not attempt to initiate more TXOPs than the maximum number of media synchronization delay TXOPs (dot11MSDTXOPMax). Otherwise, the STA will execute a CCA (Continuous Acceptance Assist) until the media synchronization delay timer expires before initiating transmission.

[0208] The default value for `dot11MSDOFDMEDthreshold` is -72 dB / mW, and the default value for the maximum media synchronization delay (TXOP) is 1. Specifically, the values ​​for the media synchronization delay timer duration (`dot11MSDTimerDuration`), the media synchronization delay OFDM ED threshold (`dot11MSDOFDMEDthreshold`), the maximum media synchronization delay (`dot11MSDTXOPMax`), and the NPCA media synchronization OFDM ED threshold (`dot11NPCAMSOFDMEDthreshold`) must be updated using the values ​​of the corresponding fields most recently sent by the AP or most recently received by the STA.

[0209] In some embodiments, the first station uses a first set of parameters on the NPCA main channel to perform a fallback procedure to compete for the channel.

[0210] By way of example and not limitation, the first parameter set includes at least one of the Enhanced Distributed Channel Access (EDCA) parameter set on the BSS primary channel and the Multi-User EDCA (MU EDCA) parameter set.

[0211] 1.5 First Frame:

[0212] In some embodiments, the method further includes: receiving a first frame sent by a second station, the first frame being used to indicate NPCA operation information of the second station and / or the first station.

[0213] When the first site is a non-AP STA, the non-AP STA receives the NPCA operation information sent by the AP and performs the NPCA operation according to the received NPCA operation information; when the first site is an AP, the non-AP STA performs the NPCA operation according to the NPCA operation information sent by the AP itself.

[0214] In some embodiments, NPCA operation information includes the NPCA media synchronization OFDM ED threshold used by the first site.

[0215] In some embodiments, the NPA media synchronization OFDM ED threshold used by the first site is carried in the NPA media synchronization OFDM ED threshold field, which is carried in the first frame.

[0216] Optionally, the NPCA media synchronization OFDM ED threshold field is carried in the NPCA operation information field, the NPCA operation information field is carried in the UHR operation information field, the UHR operation information field is carried in the UHR operation element, and the UHR operation element is carried in the first frame.

[0217] In some embodiments, NPCA operation information includes the OFDM ED threshold used by the first site.

[0218] Optionally, the OFDM ED threshold is carried in the OFDM ED threshold field.

[0219] Figure 8 illustrates a schematic diagram of the format of a UHR operation element provided in an exemplary embodiment of this application. The numbers below each field indicate the number of bytes it may occupy. In this embodiment, subfields may be simply referred to as fields.

[0220] UHR operation elements include at least one of the following subfields: Element ID, Length, Element ID Extension, UHR Operation Parameter, Basic UHR MCS and NSS Set, and UHR Operation information.

[0221] The element ID field occupies 1 byte, the length field occupies 1 byte, the element ID extension field occupies 1 byte, the UHR operation parameter field occupies a variable number of bytes, the basic UHR MCS and NSS collection fields occupies a variable number of bytes, and the UHR operation information field occupies a variable number of bytes.

[0222] The format of the UHR operation element field described above is an exemplary possibility. In different embodiments or designs, it is possible that at least one of the following designs may change: the position of the field in the frame, its arrangement order with other fields, the number of bytes occupied, the number of bits occupied, the element name, and the field name. This embodiment does not limit this.

[0223] Figure 9 illustrates the format of a UHR operation parameter field provided in an exemplary embodiment of this application. The numbers below each field indicate the number of bits it may occupy. In this embodiment, subfields may be simply referred to as fields.

[0224] The UHR operation parameter field includes at least one of the following subfields: NPCA Operation Information Present field and Reserved field.

[0225] Among them, the NPCA operation information field occupies 1 bit, and the reserved field occupies 7 bits.

[0226] The presence of the NPCA operation information field indicates whether the AP sending the field has enabled NPCA operation, and whether the UHR operation information field contains the NPCA operation information field.

[0227] For example, if the value of the NPCA operation information field is 1, it means that the NPCA operation is enabled and the NPCA operation information field exists in the UHR operation information field; if the value of the NPCA operation information field is 0, it means that the NPCA operation is not enabled and the NPCA operation information field does not exist in the UHR operation information field.

[0228] The format of the above UHR operation parameter field is an exemplary possibility. In different embodiments or different designs, it is possible that at least one of the following designs may change: the position of the above field in the frame, the order of arrangement with other fields, the number of bytes occupied, the number of bits occupied, the element name, and the field name. This embodiment does not limit this.

[0229] In some embodiments, the media synchronization duration threshold is carried in the NPCA media synchronization threshold field, which is carried in the first frame.

[0230] Figure 10 illustrates the format of an NPCA operation information field provided in an exemplary embodiment of this application. The numbers below each field indicate the number of bits it may occupy. In this embodiment, subfields may be simply referred to as fields.

[0231] The NPCA operation information field includes at least one of the following subfields: NPCA Primary Channel, NPCA Minimum Duration Threshold, NPCA Switching Delay, NPCA Switch Back Delay, NPCA Medium Synchronization Threshold, and NPCA Medium Synchronization OFDM ED Threshold.

[0232] Among them, the NPCA main channel field occupies 8 bits, the NPCA minimum duration threshold field occupies a variable number of bits, the NPCA handover delay field occupies 6 bits, the NPCA handback delay field occupies 6 bits, the NPCA media synchronization threshold field occupies 6 bits, and the NPCA media synchronization OFDM ED threshold field occupies 6 bits.

[0233] The NPCA primary channel field indicates the channel number of a channel within the BSS bandwidth range. NPCA APs and / or their associated NPCA non-AP STAs switch to this channel and perform NPCA operations on that channel. An NPCA AP is an AP that supports NPCA operations, and an NPCA non-AP STA (abbreviated as NPCA STA) is a STA that supports NPCA operations.

[0234] The NPCA Minimum Duration Threshold field represents the minimum duration of inter-BSS behavior (inter-BSS PPDU or inter-BSS TXOP), which is a necessary condition for allowing an NPCA STA to switch to the NPCA primary channel to perform NPCA operations. The encoding and maximum value of this field are yet to be determined.

[0235] The NPCA handover delay field indicates the time required for the NPCA STA to switch from the BSS main channel to the NPCA main channel, and the unit can be 4 microseconds.

[0236] The NPCA handover delay field indicates the time required for the NPCA STA to switch from the NPCA main channel to the BSS main channel, and the unit can be 4 microseconds.

[0237] The NPCA Media Synchronization Threshold field indicates the minimum duration of media synchronization loss required to trigger the start of the media synchronization recovery process on the NPCA channel, and can be in units of 4 microseconds.

[0238] In some embodiments, the value of the NPCA media synchronization OFDM ED threshold is the sum of a first preset value and a media synchronization duration threshold;

[0239] The media synchronization duration threshold indicates the minimum duration of media synchronization loss required to trigger the media synchronization recovery process on the NPCA main channel. The first preset value can be -72, 0, or other optional values.

[0240] The NPCA Media Synchronization OFDM ED Threshold field indicates the NPCA Media Synchronization OFDM ED threshold (dot11NPCAMSOFDMEDthreshold) used when a site switches to the NPCA main channel for media synchronization purposes. Its description is shown in Table 1.

[0241] Table 1

[0242] Optionally, the NPCA media synchronization OFDM ED threshold can be used as the OFDM ED threshold for channel idle detection when the first site has just switched to the NPCA main channel (this detection can be used to determine whether to start the media synchronization recovery process); or it can be used as the OFDM ED threshold after the media synchronization recovery process has been started (e.g., when the media synchronization delay timer is non-zero) during the media synchronization recovery process.

[0243] The format of the NPCA operation information field described above is an exemplary possibility. In different embodiments or designs, it is possible that at least one of the following designs may change: the position of the field in the frame, its arrangement order with other fields, the number of bytes occupied, the number of bits occupied, the element name, and the field name. This embodiment does not limit this.

[0244] In summary, the method provided in this embodiment determines whether to initiate a media synchronization recovery process when the first site switches from the BSS main channel to the NPCA main channel. If it is determined that the media synchronization recovery process should be initiated, media synchronization on the NPCA main channel can be guaranteed; if it is determined that the media synchronization recovery process should not be initiated, it indicates that there is no media synchronization problem on the NPCA main channel.

[0245] The method provided in this embodiment also determines whether to initiate the media synchronization recovery process based on different types of preset rules. According to different scenario requirements, it flexibly selects appropriate preset rules, thereby expanding the applicability of the NPCA-based channel access method.

[0246] The method provided in this embodiment also expands the applicability of the NPCA-based channel access method by listing different first times and selecting the first time that matches the scenario requirements according to different scenario requirements.

[0247] The method provided in this embodiment also lists different NPCA operation information and corresponding fields by receiving the first frame sent by the second station, and clarifies the indication method of thresholds such as NPCA media synchronization OFDM ED threshold, media synchronization duration threshold, and OFDM ED threshold.

[0248] Figure 11 shows a flowchart of an NPCA-based channel access method provided in an exemplary embodiment of this application. The method is performed by a first site and includes:

[0249] Step 1110: The first site to perform channel access on the NPCA main channel switches back to the BSS main channel from the NPCA main channel before the third time T0.

[0250] The third time T0 is determined based on the end time of the duration of the first OBSS event or the first OBSS transmission that makes the BSS main channel busy. The first OBSS event or the first OBSS transmission triggers the first station to switch from the BSS main channel to the NPCA main channel.

[0251] In some embodiments, the third time T0 is the end time of the duration of the first OBSS event or the first OBSS transmission; or, the third time T0 is the time corresponding to the sum of the end time of the duration of the first OBSS event or the first OBSS transmission and the preset frame interval.

[0252] For example, if the preset frame interval is SIFS, then the third time T0 is the time corresponding to the sum of the end time of the first OBSS event or the duration of the first OBSS transmission and SIFS.

[0253] The first OBSS event that makes the BSS primary channel busy could be a cross-BSS PPDU or a cross-BSS control frame exchange. Assuming the duration of the first OBSS event is the OBSS duration (OBSS_DURATION), then the first station needs to switch back to the BSS primary channel before the end of the OBSS duration.

[0254] Assuming the first handover delay (STA_NPCA_SWITCH_BACK_DELAY) represents the time it takes for the first station to switch back from the NPCA main channel to the BSS main channel, and the second handover delay (PeerSTA_NPCA_SWITCH_BACK_DELAY) represents the time it takes for the peer station (the second station) to switch back from the NPCA main channel to the BSS main channel, then the maximum value of the two is the maximum handover delay (MAX__NPCA_SWITCH_BACK_DELAY).

[0255] In some embodiments, the first site is an access point (AP) and the second site is a non-access point site (non-AP STA); or, the first site is a non-access point site (non-AP STA) and the second site is an access point (AP). This application does not limit this specific configuration. A non-AP STA can be simply referred to as an STA. An AP that supports NPCA operation can be called an NPCA AP, and a STA that supports NPCA operation (non-AP STA) can be called an NPCA STA.

[0256] Due to interference from OBSS events, both the first and second sites switched from the BSS primary channel to the NPCA primary channel. The first site switched to the NPCA primary channel after triggering the first OBSS event, and the second site switched to the NPCA primary channel after triggering the second OBSS event.

[0257] In some embodiments, the first OBSS event and the second OBSS event may be the same or different, or the first OBSS transmission and the second OBSS transmission may be the same or different; the embodiments of this application do not limit this.

[0258] Alternatively, an OBSS event can also be understood as an OBSS transmission. Triggering an OBSS event (OBSS activity) or OBSS transmission (OBSS transmission) has the same meaning, which refers to detecting or receiving an OBSS PPDU (i.e., a PPDU transmitted in OBSS). In this application embodiment, the OBSS event is usually used as an example for explanation.

[0259] The first OBSS event that triggers the first site to switch from the BSS main channel to the NPA main channel can also be understood as the first OBSS PPDU that triggers the first site to switch from the BSS main channel to the NPA main channel; the second OBSS event that triggers the second site to switch from the BSS main channel to the NPA main channel can also be understood as the second OBSS PPDU that triggers the second site to switch from the BSS main channel to the NPA main channel.

[0260] Figure 12 shows a schematic diagram of an OBSS scenario provided by an exemplary embodiment of this application.

[0261] In Figure 12(a), within BSS1, STA1 is associated with AP1. OBSS1 (BSS2) is the OBSS of BSS1, and STA2 corresponding to OBSS1 is associated with AP2. The OBSS events that trigger AP1 and STA1 to switch from the BSS primary channel to the NPCA primary channel are the same.

[0262] In Figure 12(b), within BSS1, STA1 is associated with AP1. OBSS1 (BSS2) is the OBSS of BSS1, and STA2 corresponding to OBSS1 is associated with AP2; OBSS2 (BSS3) is also the OBSS of BSS1, and STA3 corresponding to OBSS2 is associated with AP3.

[0263] The OBSS events that trigger AP1 and STA1 to switch from the BSS master channel to the NPCA master channel are different. The OBSS event corresponding to OBSS1 triggers STA1 to switch from the BSS master channel to the NPCA master channel, while the OBSS event corresponding to OBSS2 triggers AP1 to switch from the BSS master channel to the NPCA master channel.

[0264] In some embodiments, switching back from the NPCA main channel to the BSS main channel before the third time T0 includes: starting the switch from the NPCA main channel to the BSS main channel before the fourth time T1;

[0265] The fourth time T1 is determined based on the third time T0 and the first handover delay, which is the duration for the first station to switch back from the NPCA main channel to the BSS main channel.

[0266] The start of switching from the NPCA main channel to the BSS main channel can be understood as the start of switching from the NPCA main channel to the BSS main channel.

[0267] Optionally, the fourth time T1 is determined based on the first difference between the third time T0 and the first switchback delay.

[0268] Figure 13 shows a schematic diagram of an NPCA-based channel access method provided in an exemplary embodiment of this application.

[0269] Wherein, the third time T0 is the end time of the duration of the first OBSS event or the first OBSS transmission, and the fourth time T1 is the first difference between the third time T0 and the first handover delay. The first station needs to start switching from the NPCA main channel to the BSS main channel before the fourth time T1.

[0270] In some embodiments, the duration of the first OBSS event or the first OBSS transmission is the duration of the first OBSS TXOP or the first OBSS PPDU. The duration of the first OBSS event or the first OBSS transmission can be obtained from the preamble of the first OBSS PPDU or the frame carried by the first OBSS PPDU.

[0271] 2.1 End TXOP on the NPCA main channel:

[0272] In some embodiments, the first site is the TXOP owner, and the method further includes:

[0273] If there is not enough time to complete frame exchange before the fifth time T2 and / or the sixth time T3, terminate TXOP on the NPCA main channel or terminate frame exchange with the second station.

[0274] The second station is the peer station of the first station. The fifth time T2 is determined based on the third time T0 and the target delay. The target delay includes the first handover delay and / or the second handover delay. The first handover delay is the time it takes for the first station to switch from the NPCA main channel back to the BSS main channel, and the second handover delay is the time it takes for the second station to switch from the NPCA main channel back to the BSS main channel.

[0275] The sixth time T3 is determined based on the seventh time T4 and the second handover delay. The seventh time T4 is determined based on the end time of the duration of the second OBSS event or the second OBSS transmission. The second OBSS event or the second OBSS transmission triggers the second station to switch from the BSS main channel to the NPCA main channel.

[0276] Once both the first and second stations detect the OBSS PPDU, they switch to the NPCA main channel for channel access. For example, if the first station is the TXOP owner, it should ensure that the TXOP ends before the time corresponding to (third time T0 - first handover delay).

[0277] Optionally, the method further includes: before starting the transmission of any PPDU, checking whether there is sufficient time to complete frame switching before the fifth time T2 and / or the sixth time T3.

[0278] If there is not enough time to complete the frame exchange, the TXOP is terminated on the NPCA main channel, or the frame exchange with the second station is terminated; if there is enough time to complete the frame exchange, then the frame exchange continues.

[0279] In some embodiments, the seventh time T4 is the end time of the duration of the second OBSS event or the second OBSS transmission; or, the seventh time T4 is the time corresponding to the sum of the end time of the duration of the second OBSS event or the second OBSS transmission and the preset frame interval.

[0280] For example, if the preset frame interval is SIFS, then the seventh time T4 is the time corresponding to the sum of the end time of the duration of the second OBSS event or the second OBSS transmission and SIFS. This application does not limit this, but typically uses the example of the seventh time T4 being the end time of the duration of the second OBSS event or the second OBSS transmission for illustration.

[0281] Figure 14 shows a schematic diagram of an NPCA-based channel access method provided in an exemplary embodiment of this application.

[0282] In Figure 14(a), the third time T0 is the end time of the duration of the first OBSS event (the OBSS event corresponding to BSS2). Assuming the first station is STA, it should be ensured that the TXOP ends before the time corresponding to (third time T0 - maximum switchback delay). Since the first switchback delay is greater than the second switchback delay, the maximum switchback delay is the first switchback delay. The fifth time T2 is the difference between the third time T0 and the first switchback delay. There is not enough time to complete frame switching before the fifth time T2, therefore the first station ends the TXOP on the NPCA main channel or ends the frame switching with the second station.

[0283] In Figure 14(b), the seventh time T4 is the end time of the duration of the second OBSS event (the OBSS event corresponding to BSS3), and the sixth time T3 is the difference between the seventh time T4 and the second handover delay. There is not enough time to complete frame switching before the sixth time T3, so the first station ends TXOP on the NPCA main channel or ends frame switching with the second station.

[0284] In some embodiments, the first site is the TXOP owner, the first site is the AP, and the second site is the associated site (current STA) that performs frame exchange with the AP on the NPCA main channel. The AP's first handover delay is less than or equal to the current STA's second handover delay. If the AP performs frame exchange with the current STA after switching to the NPCA main channel, then the AP should stop frame exchange with the current STA before (third time T0 - second handover delay).

[0285] Optionally, before starting to transmit any PPDU, the AP checks whether there is enough time to complete frame switching before the third time T0 - the second switchback delay. If there is not enough time, the AP can delay data transmission with the current STA by performing frame switching with other STAs located on the NPCA main channel.

[0286] By ending TXOP on the NPCA main channel or ending frame exchange with the second station when there is not enough time to complete frame exchange before the fifth time T2 and / or the sixth time T3, channel resources are released in advance.

[0287] 2.2 Delay and data transmission between the second station:

[0288] In some embodiments, the method further includes:

[0289] If there is not enough time to complete frame switching before the fifth time T2 and / or the sixth time T3, data transmission between the second station is delayed on the NPCA main channel.

[0290] The second station is the peer station of the first station. The fifth time T2 is determined based on the third time T0 and the target delay. The target delay includes the first handover delay and / or the second handover delay. The first handover delay is the time it takes for the first station to switch from the NPCA main channel back to the BSS main channel, and the second handover delay is the time it takes for the second station to switch from the NPCA main channel back to the BSS main channel.

[0291] The sixth time T3 is determined based on the seventh time T4 and the second handover delay. The seventh time T4 is determined based on the end time of the duration of the second OBSS event or the second OBSS transmission. The second OBSS event or the second OBSS transmission triggers the second station to switch from the BSS main channel to the NPCA main channel.

[0292] Optionally, the method further includes: before starting the transmission of any PPDU, checking whether there is sufficient time to complete frame switching before the fifth time T2 and / or the sixth time T3.

[0293] If there is not enough time to complete the frame exchange, the data transmission between the second station and the NPCA main channel is delayed; if there is enough time to complete the frame exchange, then the frame exchange continues.

[0294] In some embodiments, if there is insufficient time to complete frame switching before the fifth time T2 and / or the sixth time T3, the delay in data transmission with the second station on the NPCA main channel includes at least one of the following:

[0295] If there is not enough time to complete frame switching before the fifth time T2 and / or the sixth time T3, on the NPCA main channel, data transmission with the second station is delayed by switching from the NPCA main channel to the BSS main channel.

[0296] If there is insufficient time to complete frame switching before the fifth time T2 and / or the sixth time T3, on the NPCA main channel, a random backoff count is selected by using the value of the current contention window parameter (CW[AC]), delaying data transmission with the second station.

[0297] In some embodiments, the target latency is: the maximum switchback latency, which is the larger of the first switchback latency and the second switchback latency; or, the second switchback latency; or, the first switchback latency.

[0298] Optionally, if the first OBSS event and the second OBSS event are the same, or if the first OBSS transmission and the second OBSS transmission are the same, the target delay is the maximum switchback delay.

[0299] In the case that the first OBSS event and the second OBSS event are different and the second site is an AP, or the first OBSS transmission and the second OBSS transmission are different and the second site is an AP, the target delay is the second switchback delay;

[0300] In the case that the first OBSS event and the second OBSS event are different and the first site is an AP, or the first OBSS transmission and the second OBSS transmission are different and the first site is an AP, the target delay is the first switchback delay.

[0301] Figure 15 shows a schematic diagram of an NPCA-based channel access method provided in an exemplary embodiment of this application.

[0302] The specific timing details for the fifth time T2, sixth time T3, and seventh time T4 are detailed in section 2.1 and will not be repeated here. Assuming the first and second OBSS events are the same, both corresponding to BSS2 OBSS events, the target delay is the maximum switchback delay. Since the first switchback delay is greater than the second switchback delay, the target delay is the first switchback delay. Because the first and second OBSS events are the same, the seventh time T4 is the same as the third time T0, and the fifth time T2 is the difference between the third time T0 and the first switchback delay. There is insufficient time to complete frame switching before the fifth time T2; therefore, the first station, on the NPCA main channel, delays data transmission with the second station by switching from the NPCA main channel to the BSS main channel.

[0303] In some embodiments, the seventh time T4 is determined based on the end time of the OBSS duration fed back by the second station, the OBSS duration being used to indicate the duration of the cross-BSS PPDU that triggers the second station to switch from the BSS main channel to the NPCA main channel, or the duration of the cross-BSS control frame exchange.

[0304] The OBSS duration corresponding to a cross-BSS PPDU is obtained through the TXOP duration (TXOP_DURATION) or PPDU length (PPDU Length) field in the receive vector (RXVECTOR) parameter of the cross-BSS PPDU, or the duration field of the frame carried by the cross-BSS PPDU; or,

[0305] The duration of the OBSS corresponding to the cross-BSS control frame exchange is obtained through the TXOP duration (TXOP_DURATION) parameter in the receive vector (RXVECTOR) parameter of the cross-BSS PPDU carrying the control frame, or the duration field of the frame carried by the cross-BSS PPDU carrying the control frame.

[0306] By delaying data transmission with the second station on the NPCA main channel when there is insufficient time to complete frame switching before the fifth time T2 and / or the sixth time T3, erroneous or invalid frame switching is avoided, thereby improving transmission efficiency.

[0307] 2.3 Switchback delay and corresponding fields:

[0308] In some embodiments, the first station may publish NPCA operation information by carrying UHR operation elements in the management frames it sends (e.g., beacon frames, probe response frames, association response frames, reassociation response frames).

[0309] In some embodiments, the first switchback delay is carried in the first switchback delay field sent by the first site.

[0310] Optionally, the first switchback delay field is carried in the management frame, quality of service (QoS) data frame, or control frame sent by the first site.

[0311] The NPCA AP can carry a first handover delay field and a first handover return delay field in the management frame, quality of service data frame or control frame it sends. The first handover delay field is used to indicate the NPCA AP's NPCA handover delay (the delay of switching from the BSS primary channel to the NPCA primary channel), and the first handover return delay field is used to indicate the NPCA AP's NPCA handover return delay (the delay of switching from the NPCA primary channel back to the BSS primary channel, i.e., the first handover return delay).

[0312] In some embodiments, the second switchback delay is carried in the second switchback delay field sent by the second site.

[0313] Optionally, the second switchback delay field is carried in the management frame, QoS data frame, or control frame sent by the second station.

[0314] The NPCA STA may carry a second handover delay field and a second handover return delay field in the management frame, quality of service data frame or control frame it transmits. The second handover delay field is used to indicate the NPCA handover delay of the NPCA STA (the delay of switching from the BSS primary channel to the NPCA primary channel), and the second handover return delay field is used to indicate the NPCA handover return delay of the NPCA STA (the delay of switching from the NPCA primary channel back to the BSS primary channel, i.e., the second handover return delay).

[0315] For specific implementation details of the UHR operation element and the switchback delay field, please refer to 1.5 of the embodiment in Figure 3, which will not be repeated here.

[0316] In summary, the method provided in this embodiment involves a first station performing channel access on the NPCA main channel switching back to the BSS main channel before a third time T0. The third time T0 is determined based on the end time of the duration of a first OBSS event or first OBSS transmission that makes the BSS main channel busy. The first OBSS event or first OBSS transmission triggers the first station to switch back to the NPCA main channel from the BSS main channel. This ensures that the first station can switch back to the BSS main channel before the third time T0, thus clearly defining the switchback time for the first station.

[0317] The method provided in this embodiment also releases channel resources in advance by ending TXOP on the NPCA main channel or ending frame exchange with the second station when there is not enough time to complete frame exchange before the fifth time T2 and / or the sixth time T3.

[0318] The method provided in this embodiment also improves transmission efficiency by delaying data transmission with the second station on the NPCA main channel when there is insufficient time to complete frame switching before the fifth time T2 and / or the sixth time T3, thereby avoiding erroneous or invalid frame switching.

[0319] The method provided in this embodiment also clarifies the indication method of the first and second switchback delays by listing the fields and carried frames corresponding to the first and second switchback delays.

[0320] In the above embodiments, the embodiments corresponding to FIG3 and FIG11 can be implemented individually or in combination, and this application does not limit them.

[0321] Figure 16 shows a block diagram of a first device provided in an exemplary embodiment of this application. The device can be implemented as a first site, or as part of a first site, by software or hardware or a combination of both. The device includes:

[0322] Processing module 1610 is used to determine whether to initiate the media synchronization recovery process when switching from the BSS primary channel to the NPCA primary channel.

[0323] Determining whether media synchronization is lost corresponds to determining whether to initiate the media synchronization recovery process. Specifically, if the first device determines that media synchronization is not lost, it determines not to initiate the media synchronization recovery process; if the first device determines that media synchronization is lost, it determines to initiate the media synchronization recovery process. The media synchronization recovery process can also be simply referred to as the media recovery process, and this application embodiment does not limit it to that term.

[0324] In one possible design of this embodiment, the first device is an access point (AP) and the second device is a non-access point site (non-AP STA); or, the first device is a non-access point site (non-AP STA) and the second device is an access point (AP). This embodiment does not limit the specific design, and a non-AP STA can be simply referred to as a STA. An AP that supports NPCA operation can be called an NPCA AP, and a STA that supports NPCA operation (non-AP STA) can be called an NPCA STA.

[0325] Due to interference from OBSS events, the first device and the second device switch from the BSS main channel to the NPCA main channel. The first device switches to the NPCA main channel due to triggering the first OBSS event, and the second device switches to the NPCA main channel due to triggering the second OBSS event. The first OBSS event and the second OBSS event may be the same or different. This application does not limit this, and it is usually described by taking the first OBSS event and the second OBSS event being the same.

[0326] Alternatively, an OBSS event can also be understood as an OBSS transmission. Triggering an OBSS event (OBSS activity) or OBSS transmission (OBSS transmission) has the same meaning, which refers to detecting or receiving an OBSS PPDU (i.e., a PPDU transmitted in OBSS). In this application embodiment, the OBSS event is usually used as an example for explanation.

[0327] The first OBSS event that triggers the first device to switch from the BSS main channel to the NPCA main channel can also be understood as the first OBSS PPDU that triggers the first device to switch from the BSS main channel to the NPCA main channel; the second OBSS event that triggers the second device to switch from the BSS main channel to the NPCA main channel can also be understood as the second OBSS PPDU that triggers the second device to switch from the BSS main channel to the NPCA main channel.

[0328] For specific implementation details, please refer to step 310 of the embodiment in Figure 3, which will not be repeated here.

[0329] 3.1 Preset Rules:

[0330] In one possible design of this embodiment, the processing module 1610 is used to determine, based on preset rules, whether to initiate a media synchronization recovery process or to perform channel access without losing media synchronization when switching from the BSS main channel to the NPCA main channel; the preset rules are related to at least one of the following factors:

[0331] Whether the first duration is less than or equal to the first threshold; whether the NPCA main channel is detected to be idle after switching to the NPCA main channel; whether the first PPDU is detected or received on the NPCA main channel after switching to the NPCA main channel;

[0332] The first duration is the duration between the first time and the second time. The first time is determined based on the channel access operation or channel idle / busy state before the first device switches from the BSS main channel to the NPCA main channel. The second time is the start time of the first device switching to the NPCA main channel.

[0333] In one possible design of this embodiment, the processing module 1610 is used to determine, based on preset rules, whether to initiate the media synchronization recovery process or whether to perform channel access without losing media synchronization, including at least one of the following:

[0334] (1) If the first duration is less than or equal to the first threshold, determine that the first device does not initiate the media synchronization recovery process or performs channel access in accordance with the condition of not losing media synchronization;

[0335] (2) If the first duration is less than or equal to the first threshold, and the first device detects that the NPCA main channel is idle based on the OFDM ED threshold after switching to the NPCA main channel, it is determined that the first device will not start the media synchronization recovery process or will perform channel access in accordance with the condition of not losing media synchronization.

[0336] (3) If the first duration is less than or equal to the first threshold, and the first device detects that the NPCA main channel is idle within a predetermined time interval after switching to the NPCA main channel, it is determined that the first device will not start the media synchronization recovery process or will perform channel access in accordance with the condition of not losing media synchronization.

[0337] (4) If the first duration is less than or equal to the first threshold, and the first device detects or receives the first PPDU on the NPCA main channel within a predetermined time interval after switching to the NPCA main channel, it is determined that the first device does not start the media synchronization recovery process or performs channel access in accordance with the condition of not losing media synchronization.

[0338] (5) If the first duration is less than or equal to the first threshold, and the first device detects that the NPCA main channel is idle based on the NPCA media synchronization OFDM ED threshold after switching to the NPCA main channel, it is determined that the first device will not start the media synchronization recovery process or will perform channel access in accordance with the condition of not losing media synchronization.

[0339] (6) If the first duration is less than or equal to the first threshold, and the first device detects that the NPCA main channel is idle within a predetermined time interval after switching to the NPCA main channel, based on the NPCA media synchronization OFDM ED threshold, the first device shall determine that it shall not start the media synchronization recovery process or perform channel access in accordance with the condition of not losing media synchronization.

[0340] (7) If the first duration is less than or equal to the first threshold, and the first device detects or receives the first PPDU on the NPCA main channel within a predetermined time interval after switching to the NPCA main channel, it is determined that the first device does not start the media synchronization recovery process or performs channel access in accordance with the condition of not losing media synchronization.

[0341] (8) In the case where the first duration is greater than the first threshold; or in the case where the first device does not detect that the NPCA main channel is idle based on the OFDM ED threshold after switching to the NPCA main channel; or in the case where the first device does not detect that the NPCA main channel is idle based on the OFDM ED threshold within a predetermined time interval after switching to the NPCA main channel; or in the case where the first device does not detect or receive the first PPDU on the NPCA main channel within a predetermined time interval after switching to the NPCA main channel; or in the case where the first device does not detect that the NPCA main channel is idle based on the NPCA media synchronization OFDM ED threshold after switching to the NPCA main channel; or in the case where the first device does not detect that the NPCA main channel is idle based on the NPCA media synchronization OFDM ED threshold within a predetermined time interval after switching to the NPCA main channel; or in the case where the first device does not detect or receive the first PPDU on the NPCA main channel within a predetermined time interval after switching to the NPCA main channel; or in the case where the first site does not detect or receive the first PPDU on the NPCA main channel within a predetermined time interval after switching to the NPCA main channel based on OFDM... If the ED threshold does not detect that the NPCA main channel is idle, and no PPDU is detected or received on the NPCA main channel; or if the first site, within a predetermined time interval after switching to the NPCA main channel, determines that the first device initiates the media synchronization recovery process or performs channel access as in the case of lost media synchronization, based on the NPCA media synchronization OFDM ED threshold not detecting that the NPCA main channel is idle, and no PPDU is detected or received on the NPCA main channel.

[0342] In one possible design of this embodiment, the first threshold is a media synchronization duration threshold.

[0343] In one possible design of this embodiment, whether the NPCA main channel is detected to be idle after switching to the NPCA main channel includes: whether the NPCA main channel is detected to be idle during a predetermined time interval after switching to the NPCA main channel.

[0344] In one possible design of this embodiment, NPCA primary channel idle is detected based on at least one of the following thresholds: OFDM ED threshold; NPCA media synchronization OFDM ED threshold.

[0345] Optionally, the NPCA media synchronization OFDM ED threshold is less than or equal to the OFDM ED threshold.

[0346] In one possible design of this embodiment, detecting or receiving a first PPDU includes at least one of the following: receiving an MPDU; detecting that the transmission opportunity duration parameter is not an unspecified PPDU.

[0347] For specific implementation details, please refer to section 1.1 of the embodiment shown in Figure 3, which will not be repeated here.

[0348] 3.2 First Immediate Response:

[0349] In one possible design of this embodiment, the first time includes at least one of the following:

[0350] 1) The time when the first device finishes performing frame exchange with any station, and the operation bandwidth corresponding to the frame exchange covers the NPCA main channel;

[0351] 2) The end time of OBSS PPDU transmission carrying control frames, or the end time of the TXOP where the OBSS PPDU is located, OBSS PPDU carrying control frames occupies the NPCA main channel;

[0352] 3) The expiration or clearing time of the inter-BSS network allocation vector (Inter-BSS NAV) generated by the previous OBSS PPDU transmission. The previous OBSS PPDU occupies the NPCA main channel. The previous OBSS PPDU is the most recent OBSS PPDU detected before the handover.

[0353] 4) The expiration or clearing time of the internal BSS NAV generated by the transmission of the previous internal BSS PPDU. The previous internal BSS PPDU occupies the NPCA main channel. The previous internal BSS PPDU is the most recent internal BSS PPDU detected before the handover.

[0354] For specific implementation details, please refer to section 1.2 of the embodiment shown in Figure 3, which will not be repeated here.

[0355] 3.3 First Threshold:

[0356] In one possible design of this embodiment, the first threshold is the minimum PPDU duration carrying control frames or data frames, or the sum of the minimum PPDU duration carrying control frames or data frames and the preset frame spacing.

[0357] For example, the minimum PPDU duration carrying control frames or data frames can be set to 72 microseconds. 72 microseconds is chosen to cover the PPDU length of RTS frames, CTS frames, or acknowledgment frames using a data rate of 6 MB / s and a non-HT or non-HT repeating PPDU format, as well as the PPDU length of most block acknowledgment frames.

[0358] By way of example and not limitation, the preset frame spacing includes at least one of SIFS, PIFS, and AIFS.

[0359] For example, the preset frame interval is SIFS, and the first threshold is the sum of 72 microseconds and SIFS.

[0360] In one possible design of this embodiment, the first threshold is carried in the NPCA media synchronization threshold field, which is carried in the first frame sent by the second device.

[0361] 3.4 Channel Access Rules:

[0362] If, after the first device switches to the NPCA main channel, it is determined that the first device has not lost media synchronization on the NPCA main channel, or it is determined that the media synchronization recovery process will not be initiated, then one or more of the following channel access rules shall be adopted.

[0363] Taking the first device as STA as an example, when STA is ready to transmit on the NPCA main channel, STA can initiate TXOP on the NPCA main channel, but the following exception rules apply:

[0364] a. Each time the STA switches to the NPCA main channel, the NPCA contention window [Access Category] (CW_NPCA[AC]) is initialized to a predetermined value, and a new initial value is randomly selected between 0 and CW_NPCA[AC] as the value of the backoff counter.

[0365] b. Set the queued service resource [access class] (Queued Service Resource_NPCA[AC], QSRC_NPCA[AC]) of NPCA to 0.

[0366] c. If the STA is a non-AP STA and the associated AP has prohibited untriggered uplink transmissions on the NPCA main channel, then the non-AP STA must not initiate a TXOP on the NPCA main channel.

[0367] d.STA initiates frame switching on the NPCA main channel using the NPCA initial control frame, using non-HT PPDU or non-HT repeated PPDU format, at a rate of 6MB / s, 12MB / s, or 24MB / s.

[0368] If the first device switches to the NPCA main channel and initiates a media synchronization recovery process due to loss of media synchronization, in addition to following the above channel access rules (i.e., a to d) regarding the channel access rules of the NCPA main channel, a medium synchronization delay (MediumSyncDelay) timer will also be started.

[0369] Taking the first device as an example, the media synchronization delay timer is a timer shared by all EDCA function modules (EDCAF) within the STA, and its value is set to the media synchronization delay timer duration (dot11MSDTimerDuration).

[0370] The media synchronization delay timer will be reset to zero when any of the following events occur: the STA receives an MPDU; or the STA detects that the transmission opportunity duration parameter (TXOP_DURATION) is not an unspecified PPDU.

[0371] For STAs that can obtain TXOP, when their media synchronization delay timer is non-zero, the media synchronization delay OFDM ED threshold (dot11MSDOFDMEDthreshold) or NPCA media synchronization OFDM ED threshold (dot11NPCAMSOFDMEDthreshold) should be used instead of the OFDM ED threshold (dot11OFDMEDThreshold) to detect the channel idle / busy state in the primary 20MHz channel.

[0372] If the STA obtains a TXOP while the media synchronization delay timer is non-zero, the STA should do the following: After the media synchronization delay timer begins its countdown, it should not attempt to initiate more TXOPs than the maximum number of media synchronization delay TXOPs (dot11MSDTXOPMax). Otherwise, the STA will execute a CCA (Continuous Acceptance Assist) until the media synchronization delay timer expires before initiating transmission.

[0373] The default value for `dot11MSDOFDMEDthreshold` is -72 dB / mW, and the default value for the maximum media synchronization delay (TXOP) is 1. Specifically, the values ​​for the media synchronization delay timer duration (`dot11MSDTimerDuration`), the media synchronization delay OFDM ED threshold (`dot11MSDOFDMEDthreshold`), the maximum media synchronization delay (`dot11MSDTXOPMax`), and the NPCA media synchronization OFDM ED threshold (`dot11NPCAMSOFDMEDthreshold`) must be updated using the values ​​of the corresponding fields most recently sent by the AP or most recently received by the STA.

[0374] In one possible design of this embodiment, the first device uses a first parameter set on the NPCA main channel to perform a fallback procedure to compete for the channel.

[0375] By way of example and not limitation, the first parameter set includes at least one of the EDCA parameter set on the BSS main channel and the MU EDCA parameter set.

[0376] 3.5 First Frame:

[0377] In one possible design of this embodiment, the receiving module 1620 is used to receive a first frame sent by the second device, the first frame being used to indicate NPCA operation information of the second device.

[0378] In one possible design of this embodiment, the NPCA operation information includes the NPCA media synchronization OFDM ED threshold used by the first device.

[0379] In one possible design of this embodiment, the NPCA media synchronization OFDM ED threshold used by the first device is carried in the NPCA media synchronization OFDM ED threshold field, which is carried in the first frame.

[0380] Optionally, the NPCA media synchronization OFDM ED threshold field is carried in the NPCA operation information field, the NPCA operation information field is carried in the UHR operation information field, the UHR operation information field is carried in the UHR operation element, and the UHR operation element is carried in the first frame.

[0381] In one possible design of this embodiment, the media synchronization duration threshold is carried in the NPCA media synchronization threshold field, which is carried in the first frame.

[0382] In one possible design of this embodiment, the value of the NPCA media synchronization OFDM ED threshold is the sum of a first preset value and a media synchronization duration threshold; wherein, the media synchronization duration threshold is used to indicate the minimum duration of media synchronization loss required to trigger the initiation of the media synchronization recovery procedure on the NPCA main channel. The first preset value can be -72 or 0 or other optional values.

[0383] In one possible design of this embodiment, the NPCA operation information includes the OFDM ED threshold used by the first device.

[0384] Optionally, the OFDM ED threshold is carried in the OFDM ED threshold field.

[0385] For specific implementation details, please refer to section 1.5 of the embodiment shown in Figure 3, which will not be repeated here.

[0386] This embodiment uses one processing module 1610 and one receiving module 1620 as an example for illustration, and the number of processing modules 1610 and receiving modules 1620 is not limited.

[0387] For a description of the functions of the processing module 1610, please refer to step 310 in the embodiment shown in Figure 3. For a description of the functions of the receiving module 1620, please refer to step 310 in the embodiment shown in Figure 3.

[0388] Figure 17 shows a block diagram of a first device provided in an exemplary embodiment of this application. This device can be implemented as a first device or as part of a first device by software or hardware or a combination of both. The device performs channel access on the NPCA main channel. The device includes:

[0389] Processing module 1710 is used to switch back from the NPCA main channel to the BSS main channel before the third time T0;

[0390] The third time T0 is determined based on the end time of the duration of the first OBSS event or the first OBSS transmission that makes the BSS main channel busy. The first OBSS event or the first OBSS transmission triggers the first device to switch from the BSS main channel to the NPCA main channel.

[0391] In one possible design of this embodiment, the third time T0 is the end time of the duration of the first OBSS event or the first OBSS transmission; or, the third time T0 is the time corresponding to the sum of the end time of the duration of the first OBSS event or the first OBSS transmission and the preset frame interval.

[0392] In one possible design of this embodiment, the first device is an access point (AP) and the second device is a non-access point site (non-AP STA); or, the first device is a non-access point site (non-AP STA) and the second device is an access point (AP). This embodiment does not limit the specific design, and a non-AP STA can be simply referred to as a STA. An AP that supports NPCA operation can be called an NPCA AP, and a STA that supports NPCA operation (non-AP STA) can be called an NPCA STA.

[0393] Due to interference from OBSS events, both the first and second devices switched from the BSS main channel to the NPCA main channel. The first device switched to the NPCA main channel after triggering the first OBSS event, and the second device switched to the NPCA main channel after triggering the second OBSS event.

[0394] In one possible design of this embodiment, the first OBSS event and the second OBSS event may be the same or different, and this application embodiment does not limit this.

[0395] Alternatively, an OBSS event can also be understood as an OBSS transmission. Triggering an OBSS event (OBSS activity) or OBSS transmission (OBSS transmission) has the same meaning, which refers to detecting or receiving an OBSS PPDU (i.e., a PPDU transmitted in OBSS). In this application embodiment, the OBSS event is usually used as an example for explanation.

[0396] The first OBSS event that triggers the first device to switch from the BSS main channel to the NPCA main channel can also be understood as the first OBSS PPDU that triggers the first device to switch from the BSS main channel to the NPCA main channel; the second OBSS event that triggers the second device to switch from the BSS main channel to the NPCA main channel can also be understood as the second OBSS PPDU that triggers the second device to switch from the BSS main channel to the NPCA main channel.

[0397] For specific implementation details, please refer to step 1110 of the embodiment in Figure 11, which will not be repeated here.

[0398] In one possible design of this embodiment, switching back from the NPCA main channel to the BSS main channel before the third time T0 includes: starting the switch from the NPCA main channel to the BSS main channel before the fourth time T1.

[0399] The fourth time T1 is determined based on the third time T0 and the first switchback delay, which is the duration for the first device to switch back from the NPCA main channel to the BSS main channel.

[0400] The start of switching from the NPCA main channel to the BSS main channel can be understood as the start of switching from the NPCA main channel to the BSS main channel.

[0401] Optionally, the fourth time T1 is determined based on the first difference between the third time T0 and the first switchback delay.

[0402] For specific implementation details, please refer to the embodiment shown in Figure 13, which will not be repeated here.

[0403] 4.1 End TXOP on the NPCA main channel:

[0404] In one possible design of this embodiment, the first device is the TXOP owner, and the method further includes:

[0405] If there is not enough time to complete frame exchange before the fifth time T2 and / or the sixth time T3, the TXOP is terminated on the NPCA main channel, or the frame exchange with the second device is terminated.

[0406] Wherein, the second device is the peer station of the first device, and the fifth time T2 is determined based on the third time T0 and the target delay. The target delay includes the first handover delay and / or the second handover delay. The first handover delay is the time for the first device to switch from the NPCA main channel back to the BSS main channel, and the second handover delay is the time for the second device to switch from the NPCA main channel back to the BSS main channel.

[0407] The sixth time T3 is determined based on the seventh time T4 and the second handover delay. The seventh time T4 is determined based on the end time of the duration of the second OBSS event or the second OBSS transmission. The second OBSS event or the second OBSS transmission triggers the second device to switch from the BSS main channel to the NPCA main channel.

[0408] After both the first and second devices detect the OBSS PPDU, they switch to the NPCA main channel for channel access. For example, if the first device is the TXOP owner, it should ensure that the TXOP ends before the time corresponding to (third time T0 - first switchback delay).

[0409] Optionally, the method further includes: before starting the transmission of any PPDU, checking whether there is sufficient time to complete frame switching before the fifth time T2 and / or the sixth time T3.

[0410] If there is not enough time to complete the frame exchange, the TXOP is terminated on the NPCA main channel, or the frame exchange with the second device is terminated; if there is enough time to complete the frame exchange, then the frame exchange continues.

[0411] In one possible design of this embodiment, the seventh time T4 is the end time of the duration of the second OBSS event or the second OBSS transmission; or, the seventh time T4 is the time corresponding to the sum of the end time of the duration of the second OBSS event or the second OBSS transmission and the preset frame interval.

[0412] For example, if the preset frame interval is SIFS, then the seventh time T4 is the time corresponding to the sum of the end time of the duration of the second OBSS event or the second OBSS transmission and SIFS. This application does not limit this, but typically uses the example of the seventh time T4 being the end time of the duration of the second OBSS event or the second OBSS transmission for illustration.

[0413] For specific implementation details, please refer to section 2.1 of the embodiment shown in Figure 11, which will not be repeated here.

[0414] 4.2 Delay in data transmission between the second device and the third device:

[0415] In one possible design of this embodiment, the method further includes:

[0416] If there is not enough time to complete frame switching before the fifth time T2 and / or the sixth time T3, data transmission between the second device is delayed on the NPCA main channel.

[0417] Wherein, the second device is the peer station of the first device, and the fifth time T2 is determined based on the third time T0 and the target delay. The target delay includes the first handover delay and / or the second handover delay. The first handover delay is the time for the first device to switch from the NPCA main channel back to the BSS main channel, and the second handover delay is the time for the second device to switch from the NPCA main channel back to the BSS main channel.

[0418] The sixth time T3 is determined based on the seventh time T4 and the second handover delay. The seventh time T4 is determined based on the end time of the duration of the second OBSS event or the second OBSS transmission. The second OBSS event or the second OBSS transmission triggers the second device to switch from the BSS main channel to the NPCA main channel.

[0419] Optionally, the method further includes: before starting the transmission of any PPDU, checking whether there is sufficient time to complete frame switching before the fifth time T2 and / or the sixth time T3.

[0420] If there is not enough time to complete the frame exchange, the data transmission between the second device and the NPCA main channel is delayed; if there is enough time to complete the frame exchange, then the frame exchange continues.

[0421] In one possible design of this embodiment, if there is insufficient time to complete frame switching before the fifth time T2 and / or the sixth time T3, the delay in data transmission with the second device on the NPCA main channel includes at least one of the following:

[0422] If there is not enough time to complete frame switching before the fifth time T2 and / or the sixth time T3, on the NPCA main channel, by switching from the NPCA main channel to the BSS main channel, the data transmission with the second device is delayed;

[0423] If there is insufficient time to complete frame switching before the fifth time T2 and / or the sixth time T3, on the NPCA main channel, a random backoff count is selected by using the value of the current contention window parameter (CW[AC]) to delay data transmission with the second device.

[0424] In one possible design of this embodiment, the target latency is: the maximum switchback latency, which is the larger of the first switchback latency and the second switchback latency; or, the second switchback latency; or, the first switchback latency.

[0425] Optionally, if the first OBSS event and the second OBSS event are the same, or if the first OBSS transmission and the second OBSS transmission are the same, the target delay is the maximum switchback delay.

[0426] In the case that the first OBSS event and the second OBSS event are different and the second device is an AP, or the first OBSS transmission and the second OBSS transmission are different and the second device is an AP, the target delay is the second switchback delay;

[0427] In the case that the first OBSS event and the second OBSS event are different and the first device is an AP, or the first OBSS transmission and the second OBSS transmission are different and the first device is an AP, the target delay is the first switchback delay.

[0428] In one possible design of this embodiment, the seventh time T4 is determined based on the end time of the OBSS duration fed back by the second device. The OBSS duration is used to indicate the duration of the cross-BSS PPDU that triggers the second device to switch from the BSS main channel to the NPCA main channel, or the duration of the cross-BSS control frame exchange.

[0429] For specific implementation details, please refer to section 2.2 of the embodiment shown in Figure 11, which will not be repeated here.

[0430] 4.3 Switchback delay and corresponding fields:

[0431] In one possible design of this embodiment, the first device can publish NPCA operation information by carrying UHR operation elements in the transmitted management frames (e.g., beacon frames, probe response frames, association response frames, reassociation response frames).

[0432] In one possible design of this embodiment, the first switchback delay is carried in the first switchback delay field sent by the first device.

[0433] Optionally, the first switchback delay field is carried in the management frame, quality of service (QoS) data frame, or control frame sent by the first device.

[0434] In one possible design of this embodiment, the second switchback delay is carried in the second switchback delay field sent by the second device.

[0435] Optionally, the second switchback delay field is carried in the management frame, QoS data frame, or control frame sent by the second device.

[0436] For specific implementation details of the UHR operation element and the switchback delay field, please refer to 1.5 of the embodiment in Figure 3, which will not be repeated here.

[0437] For specific implementation details, please refer to section 2.3 of the embodiment shown in Figure 11, which will not be repeated here.

[0438] This embodiment uses one processing module 1710 as an example, and the number of processing modules 1710 is not limited.

[0439] For a description of the functions of the processing module 1710, please refer to step 1110 in the embodiment shown in Figure 11.

[0440] Figure 18 shows a schematic diagram of the structure of a first station provided in an exemplary embodiment of this application. The first station 1800 may include a processor 1801, a transceiver 1802, and a memory 1803. The processor 1801 can be used to control transmission and / or reception, such as to perform the functions of the processing module 1610 described above. The transceiver 1802 can be used to implement transmission and / or reception functions, such as to implement the functions of the receiving module 1620 described above.

[0441] Processor 1801 includes one or more processing cores. Processor 1801 executes various functional applications and information processing by running software programs and modules. Processor 1801 is used to determine whether to initiate the media synchronization recovery process when switching from the BSS main channel to the NPCA main channel.

[0442] The transceiver 1802 may include a receiver and a transmitter, for example, the receiver and transmitter may be implemented as the same wireless communication component, which may include a wireless communication chip and a radio frequency antenna.

[0443] The memory 1803 can be connected to the processor 1801 and the transceiver 1802.

[0444] The memory 1803 can be used to store a computer program executed by the processor, and the processor 1801 is used to execute the computer program to implement the various steps in the above method embodiments.

[0445] Furthermore, the memory 1803 can be implemented by any type of volatile or non-volatile storage device or a combination thereof, including but not limited to: magnetic disks or optical disks, electrically erasable programmable read-only memory, erasable programmable read-only memory, static on-demand memory, read-only memory, magnetic memory, flash memory, and programmable read-only memory.

[0446] For details not described in this embodiment, please refer to the method-side embodiment above, which will not be repeated here.

[0447] Figure 19 shows a schematic diagram of the structure of a first station provided in an exemplary embodiment of this application. The first station 1900 may include a processor 1901, a transceiver 1902, and a memory 1903. The processor 1901 can be used to control transmission and / or reception, such as to perform the functions of the processing module 1710 described above. The transceiver 1902 can be used to implement transmission and / or reception functions.

[0448] Processor 1901 includes one or more processing cores. Processor 1901 executes various functional applications and information processing by running software programs and modules. Processor 1901 is used to perform channel access for a first station on the NPCA main channel, switching back from the NPCA main channel to the BSS main channel before a third time T0; wherein the third time T0 is determined based on the end time of the duration of a first OBSS event or first OBSS transmission that makes the BSS main channel busy, and the first OBSS event or first OBSS transmission triggers the first station to switch from the BSS main channel to the NPCA main channel.

[0449] Transceiver 1902 may include a receiver and a transmitter. For example, transceiver 1902 may include a wired communication component, which may include a wired communication chip and a wired interface (such as a fiber optic interface). Optionally, transceiver 1902 may also include a wireless communication component, which may include a wireless communication chip and a radio frequency antenna.

[0450] The memory 1903 can be connected to the processor 1901 and the transceiver 1902.

[0451] The memory 1903 can be used to store a computer program executed by the processor, and the processor 1901 is used to execute the computer program to implement the various steps in the above method embodiments.

[0452] Furthermore, the memory 1903 can be implemented by any type of volatile or non-volatile storage device or a combination thereof, including but not limited to: magnetic disks or optical disks, electrically erasable programmable read-only memory, erasable programmable read-only memory, static on-demand memory, read-only memory, magnetic memory, flash memory, and programmable read-only memory.

[0453] For details not described in this embodiment, please refer to the method-side embodiment above, which will not be repeated here.

[0454] This application also provides a computer-readable storage medium storing a computer program for execution by a processor to implement the NPCA-based channel access method at the first site. In some embodiments, the computer-readable storage medium may include ROM (Read-Only Memory), RAM (Random-Access Memory), SSD (Solid State Drives), or optical disc, etc. The random access memory may include ReRAM (Resistance Random Access Memory) and DRAM (Dynamic Random Access Memory).

[0455] This application also provides a chip, which includes programmable logic circuits and / or program instructions. When the chip is running on a first site, it is used to implement the above-described NPCA-based channel access method on the first site side.

[0456] This application also provides a chip, which includes programmable logic circuits and / or program instructions. When the chip is running on a first site, it is used to implement the above-described NPCA-based channel access method on the first site side.

[0457] This application embodiment also provides a first chip, which includes programmable logic circuits and / or program instructions. When the first chip is running on a first site, it is used to "determine whether to initiate the media synchronization recovery process in the event of switching from the BSS main channel to the NPCA main channel".

[0458] This application embodiment also provides a second chip, which includes programmable logic circuits and / or program instructions. When the second chip is running on a first site, it is used to "execute channel access on the NPCA main channel of the first site, and switch from the NPCA main channel back to the BSS main channel before a third time T0; wherein the third time T0 is determined based on the end time of the duration of a first OBSS event or a first OBSS transmission that makes the BSS main channel busy, and the first OBSS event or the first OBSS transmission triggers the first site to switch from the BSS main channel to the NPCA main channel."

[0459] This application also provides a computer program product, which includes a computer program stored in a computer-readable storage medium. The processor reads and executes the computer program from the computer-readable storage medium to implement the above-described NPCA-based channel access method at the first site.

[0460] It should be understood that the term "instruction" mentioned in the embodiments of this application 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.

[0461] In the description of the embodiments of this application, the term "correspondence" may indicate that there is a direct or indirect correspondence between two things, or that there is an association between two things, or that there is a relationship of instruction and being instructed, configuration and being configured, etc.

[0462] In some embodiments of this application, "predefined" 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 a first site and a second site). This application does not limit the specific implementation method. For example, predefined can refer to what is defined in the protocol.

[0463] In some embodiments of this application, "protocol" may refer to standard protocols in the field of communications, such as LTE protocol, NR protocol and related protocols applied to future communication systems, and this application does not limit it.

[0464] In this article, "multiple" refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone. The character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0465] In this article, "greater than or equal to" can mean greater than or equal to, and "less than or equal to" can mean less than or equal to.

[0466] Furthermore, the step numbers described herein are merely illustrative of one possible execution order between steps. In some other embodiments, the steps may not be executed in the order of their numbers, such as two steps with different numbers being executed simultaneously, or two steps with different numbers being executed in the reverse order of the illustration. This application does not limit this.

[0467] Those skilled in the art will recognize that the functions described in the embodiments of this application in one or more of the above examples can be implemented using hardware, software, firmware, or any combination thereof. When implemented using software, these functions can be stored in a computer-readable medium or transmitted as one or more instructions or code on a computer-readable medium. Computer-readable media include computer storage media and communication media, wherein communication media include any medium that facilitates the transfer of a computer program from one place to another. Storage media can be any available medium that can be accessed by a general-purpose or special-purpose computer.

[0468] The above are merely exemplary embodiments of this application and are not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application shall be included within the protection scope of this application.

Claims

1. A channel access method based on Non-Master Channel Access (NPCA), characterized in that, The method is performed by a first site, and the method includes: In the event of switching from the Basic Service Set (BSS) primary channel to the NPCA primary channel, determine whether to initiate the media synchronization recovery procedure or to perform channel access without losing media synchronization.

2. The method of claim 1, wherein, In the case of switching from the Basic Service Set (BSS) primary channel to the NPCA primary channel, determining whether to initiate the media synchronization recovery procedure or to perform channel access without losing media synchronization includes: In the event of switching from the BSS main channel to the NPCA main channel, a decision is made based on preset rules to determine whether to initiate a media synchronization recovery procedure or to perform channel access without losing media synchronization; the preset rules are related to at least one of the following factors: Whether the first duration is less than or equal to the first threshold; whether the NPCA main channel is detected to be idle after switching to the NPCA main channel; whether the first physical layer protocol data unit (PPDU) is detected or received on the NPCA main channel after switching to the NPCA main channel; wherein, the first duration is the duration between the first time and the second time, the first time is determined based on the channel access operation or channel idle / busy state before the first station switches from the BSS main channel to the NPCA main channel, and the second time is the start time of the first station switching to the NPCA main channel.

3. The method of claim 2, wherein, The first threshold is the media synchronization duration threshold.

4. The method of claim 2, wherein, The step of determining whether the NPCA main channel is detected to be idle after switching to the NPCA main channel includes: whether the NPCA main channel is detected to be idle during a predetermined time interval after switching to the NPCA main channel.

5. The method of claim 4, wherein, The NPCA main channel idle is detected based on at least one of the following thresholds: Orthogonal Frequency Division Multiplexing Energy Detection (OFDM) ED threshold; NPCA Media Synchronization (OFDM) ED threshold.

6. The method according to any one of claims 2 to 5, characterized in that, The step of determining whether to initiate the media synchronization recovery process or to perform channel access without losing media synchronization based on preset rules includes at least one of the following: If the first duration is less than or equal to the first threshold, it is determined that the first site does not initiate the media synchronization recovery process or performs channel access without losing media synchronization. If the first duration is less than or equal to the first threshold, and the first station detects that the NPCA main channel is idle based on the OFDM ED threshold after switching to the NPCA main channel, it is determined that the first station will not start the media synchronization recovery process or will perform channel access without losing media synchronization. If the first duration is less than or equal to the first threshold, and the first station detects that the NPCA main channel is idle within a predetermined time interval after switching to the NPCA main channel, based on the OFDM ED threshold, it is determined that the first station will not initiate the media synchronization recovery process or will perform channel access without losing media synchronization. In a case that the first duration is less than or equal to the first threshold, and the first PPDU is detected or received on the NPCA primary channel within the predetermined time interval after the first station switches to the NPCA primary channel, the first station is determined to not initiate the medium synchronization recovery procedure or perform channel access as if no medium synchronization is lost. In a case that the first duration is less than or equal to the first threshold, and the NPCA primary channel is detected to be idle based on a NPCA medium synchronization OFDM ED threshold after the first station switches to the NPCA primary channel, the first station is determined to not initiate the medium synchronization recovery procedure or perform channel access as if no medium synchronization is lost. In a case that the first duration is less than or equal to the first threshold, and the NPCA primary channel is detected to be idle based on the NPCA medium synchronization OFDM ED threshold within the predetermined time interval after the first station switches to the NPCA primary channel, the first station is determined to not initiate the medium synchronization recovery procedure or perform channel access as if no medium synchronization is lost. In a case that the first duration is less than or equal to the first threshold, and the first PPDU is detected or received on the NPCA primary channel within the predetermined time interval after the first station switches to the NPCA primary channel, the first station is determined to not initiate the medium synchronization recovery procedure or perform channel access as if no medium synchronization is lost. In the following situations: the first duration exceeds the first threshold; or the first station, after switching to the NPCA main channel, does not detect the NPCA main channel being idle based on the OFDM ED threshold; or the first station, within the predetermined time interval after switching to the NPCA main channel, does not detect the NPCA main channel being idle based on the OFDM ED threshold; or the first station, within the predetermined time interval after switching to the NPCA main channel, does not detect or receive the first PPDU on the NPCA main channel; or the first station, after switching to the NPCA main channel, does not detect the NPCA main channel being idle based on the NPCA media synchronization OFDM ED threshold; or the first station, within the predetermined time interval after switching to the NPCA main channel, does not detect the NPCA main channel being idle based on the NPCA media synchronization OFDM ED threshold; or the first station, within the predetermined time interval after switching to the NPCA main channel, does not detect or receive the first PPDU on the NPCA main channel; or the first station, within the predetermined time interval after switching to the NPCA main channel, based on the OFDM ED threshold; If the ED threshold does not detect that the NPCA main channel is idle, and the first PPDU is not detected or received on the NPCA main channel; or if the first station, within the predetermined time interval after switching to the NPCA main channel, determines that the first station initiates the media synchronization recovery process or performs channel access as in the case of lost media synchronization, based on the NPCA media synchronization OFDM ED threshold not detecting that the NPCA main channel is idle, and the first PPDU is not detected or received on the NPCA main channel.

7. The method of claim 6, wherein, The detection or receipt of the first PPDU includes at least one of the following: Received Media Access Control Protocol Data Unit (MPDU); detected that the Transmission Opportunity Duration parameter is not an unspecified PPDU.

8. The method according to any one of claims 5 to 7, characterized in that, The NPCA media synchronization OFDM ED threshold is less than or equal to the OFDM ED threshold.

9. The method according to any one of claims 2 to 8, characterized in that, The first threshold is the minimum PPDU duration carrying control frames or data frames, or the first threshold is the sum of the minimum PPDU duration carrying control frames or data frames and the preset frame spacing.

10. The method of claim 9, wherein, The preset frame spacing includes at least one of Short Inter-Frame Spacing (SIFS), Point Coordination Function Inter-Frame Spacing (PIFS), and Arbitration Inter-Frame Spacing (AIFS).

11. The method according to any one of claims 2 to 10, characterized in that, The first time includes at least one of the following: the time when the first station finishes performing frame exchange with any station, wherein the operating bandwidth corresponding to the frame exchange covers the NPCA main channel; the time when the transmission of an Overlapping Basic Service Set (OBSS) PPDU carrying a control frame ends, or the time when the transmission opportunity (TXOP) to which the OBSS PPDU is located ends, wherein the OBSS PPDU carrying the control frame occupies the NPCA main channel; the time when the cross-BSS network allocation vector (NAV) generated by the transmission of the previous OBSS PPDU expires or is cleared, wherein the previous OBSS PPDU occupies the NPCA main channel; the time when the internal BSS NAV generated by the transmission of the previous internal BSS PPDU expires or is cleared, wherein the previous internal BSS PPDU occupies the NPCA main channel.

12. The method according to any one of claims 1 to 11, characterized in that, The method further includes: Receive a first frame sent by the second station, the first frame being used to indicate NPCA operation information of the second station and / or the first station.

13. The method of claim 12, wherein, The NPCA operation information includes the NPCA media synchronization OFDM ED threshold used by the first site.

14. The method of claim 13, wherein, The NPCA media synchronization OFDM ED threshold used by the first site is carried in the NPCA media synchronization OFDM ED threshold field, which is carried in the first frame.

15. The method according to claim 13 or 14, characterized in that, The value of the NPCA media synchronization OFDM ED threshold is the sum of a first preset value and a media synchronization duration threshold; wherein, the media synchronization duration threshold is used to indicate the minimum duration of media synchronization loss required to trigger the start of the media synchronization recovery process on the NPCA main channel.

16. The method of claim 15, wherein, The media synchronization duration threshold is carried in the NPCA media synchronization threshold field, and the NPCA media synchronization threshold field is carried in the first frame.

17. The method of claim 12, wherein, The NPCA operation information includes the OFDM ED threshold used by the first site.

18. The method of claim 12, wherein, The OFDM ED threshold is carried in the OFDM ED threshold field.

19. A method for channel access based on non-primary channel access (NPCA), the method comprising: The method is performed by a first site, and the method includes: The first site that performs channel access on the NPCA main channel switches back from the NPCA main channel to the Basic Service Set (BSS) main channel before the third time T0. The third time T0 is determined based on the end time of the duration of the first overlapping basic service set (OBSS) event or the first OBSS transmission that makes the BSS main channel busy. The first OBSS event or the first OBSS transmission triggers the first station to switch from the BSS main channel to the NPCA main channel.

20. The method of claim 19, wherein, The switching from the NPCA main channel back to the BSS main channel before the third time T0 includes: starting the switching from the NPCA main channel to the BSS main channel before the fourth time T1; The fourth time T1 is determined based on the third time T0 and the first switchback delay, where the first switchback delay is the duration for the first station to switch back from the NPCA main channel to the BSS main channel.

21. The method of claim 20, wherein, The fourth time T1 is determined based on the first difference between the third time T0 and the first cut-back delay.

22. The method of any one of claims 19 to 21, wherein, The first site is the owner of the transmission opportunity (TXOP), and the method further includes: If there is not enough time to complete frame exchange before the fifth time T2 and / or the sixth time T3, the TXOP shall be terminated on the NPCA main channel, or the frame exchange with the second station shall be terminated. Wherein, the second station is the peer station of the first station, the fifth time T2 is determined based on the third time T0 and the target delay, the target delay includes a first switchback delay and / or a second switchback delay, the first switchback delay is the duration for the first station to switch from the NPCA main channel back to the BSS main channel, and the second switchback delay is the duration for the second station to switch from the NPCA main channel back to the BSS main channel; the sixth time T3 is determined based on the seventh time T4 and the second switchback delay, the seventh time T4 is determined based on the end time of the duration of the second OBSS event or the second OBSS transmission, the second OBSS event or the second OBSS transmission triggers the second station to switch from the BSS main channel to the NPCA main channel.

23. The method of any one of claims 19 to 21, wherein, The method further includes: If there is not enough time to complete frame exchange before the fifth time T2 and / or the sixth time T3, data transmission between the second station is delayed on the NPCA main channel. Wherein, the second station is the peer station of the first station, the fifth time T2 is determined based on the third time T0 and the target delay, the target delay includes a first switchback delay and / or a second switchback delay, the first switchback delay is the duration for the first station to switch from the NPCA main channel back to the BSS main channel, and the second switchback delay is the duration for the second station to switch from the NPCA main channel back to the BSS main channel; the sixth time T3 is determined based on the seventh time T4 and the second switchback delay, the seventh time T4 is determined based on the end time of the duration of the second OBSS event or the second OBSS transmission, the second OBSS event or the second OBSS transmission triggers the second station to switch from the BSS main channel to the NPCA main channel.

24. The method of claim 22 or 23, wherein, The seventh time T4 is the end time of the duration of the second OBSS event or the second OBSS transmission; or, the seventh time T4 is the time corresponding to the sum of the end time of the duration of the second OBSS event or the second OBSS transmission and the preset frame interval.

25. The method of any one of claims 22 to 24, wherein, The first OBSS event and the second OBSS event are the same or different, or the first OBSS transmission and the second OBSS transmission are the same or different.

26. The method of any one of claims 23 to 25, wherein, The method further includes: Before starting the transmission of any PPDU, check whether there is enough time to complete frame switching before the fifth time T2 and / or the sixth time T3.

27. The method of any one of claims 23 to 26, wherein, In the event that there is insufficient time to complete frame switching before the fifth time T2 and / or the sixth time T3, the delay in data transmission with the second station on the NPCA main channel includes at least one of the following: If there is insufficient time to complete frame exchange before the fifth time T2 and / or the sixth time T3, data transmission with the second station is delayed on the NPCA main channel by switching from the NPCA main channel to the BSS main channel; if there is insufficient time to complete frame exchange before the fifth time T2 and / or the sixth time T3, data transmission with the second station is delayed on the NPCA main channel by selecting a random backoff count using the value of the current contention window parameter.

28. The method of any one of claims 22 to 27, wherein, The target latency is: the maximum switchback latency, which is the larger of the first switchback latency and the second switchback latency; or, the second switchback latency; or, the first switchback latency.

29. The method of claim 28, wherein, When the first OBSS event and the second OBSS event are the same, or when the first OBSS transmission and the second OBSS transmission are the same, the target latency is the maximum switchback latency; when the first OBSS event and the second OBSS event are different and the second site is an AP, or when the first OBSS transmission and the second OBSS transmission are different and the second site is an AP, the target latency is the second switchback latency; when the first OBSS event and the second OBSS event are different and the first site is an AP, or when the first OBSS transmission and the second OBSS transmission are different and the first site is an AP, the target latency is the first switchback latency.

30. The method of any one of claims 22 to 29, wherein, The seventh time T4 is determined based on the end time of the OBSS duration fed back by the second station. The OBSS duration is used to indicate the duration of the cross-BSS PPDU that triggers the second station to switch from the BSS main channel to the NPCA main channel, or the duration of the cross-BSS control frame exchange.

31. The method of claim 30, wherein, The duration of the OBSS is obtained through the receive vector parameters of the cross-BSS PPDU, or the PPDU length, or the duration field of the frame carried by the cross-BSS PPDU; or, the duration of the OBSS is obtained through the receive vector parameters of the cross-BSS PPDU carrying the control frame, or the duration field of the frame carried by the cross-BSS PPDU carrying the control frame.

32. The method of any one of claims 20 to 31, wherein, The first switchback delay is carried in the first switchback delay field sent by the first site.

33. The method of claim 32, wherein, The first switchback delay field is carried in the management frame, QoS data frame, or control frame sent by the first site.

34. The method of any one of claims 22 to 31, wherein, The second switchback delay is carried in the second switchback delay field sent by the second station.

35. The method of claim 34, wherein, The second switchback delay field is carried in the management frame, QoS data frame, or control frame sent by the second station.

36. The method of any one of claims 19 to 35, wherein, The third time T0 is the end time of the duration of the first OBSS event or the first OBSS transmission; or, the third time T0 is the time corresponding to the sum of the end time of the duration of the first OBSS event or the first OBSS transmission and the preset frame interval.

37. A first apparatus, comprising: The first device includes: The processing module is used to determine whether to initiate the media synchronization recovery process or to perform channel access without losing media synchronization when switching from the Basic Service Set (BSS) primary channel to a non-primary channel accessing the NPCA primary channel.

38. A first apparatus, comprising: The first device performs channel access on the NPCA main channel (non-main channel access), and the first device includes: The processing module is used to switch back from the NPCA main channel to the Basic Service Set (BSS) main channel before the third time T0. The third time T0 is determined based on the end time of the duration of the first overlapping basic service set (OBSS) event or the first OBSS transmission that makes the BSS main channel busy. The first OBSS event or the first OBSS transmission triggers the first station to switch from the BSS main channel to the NPCA main channel.

39. A first station, comprising: The first site includes: A processor; a transceiver connected to the processor; a memory for storing executable instructions of the processor; wherein the processor is configured to load and execute the executable instructions to implement the NPCA-based channel access method as claimed in any one of claims 1 to 18; and / or the NPCA-based channel access method as claimed in any one of claims 19 to 36.

40. A computer-readable storage medium, comprising: The computer-readable storage medium stores at least one program, which is loaded and executed by a processor to implement the NPCA-based channel access method as described in any one of claims 1 to 18; and / or the NPCA-based channel access method as described in any one of claims 19 to 36.

41. A first chip, comprising: The first chip includes programmable logic circuits and / or program instructions, and the first chip is used to implement the NPCA-based channel access method according to any one of claims 1 to 18.

42. A second chip comprising: The second chip includes programmable logic circuits and / or program instructions, and is used to implement the NPCA-based channel access method as described in any one of claims 19 to 36.

43. A computer program product, characterised in that, The computer program product includes computer instructions stored in a computer-readable storage medium, a processor retrieving the computer instructions from the computer-readable storage medium, and the processor executing the computer instructions to implement the NPCA-based channel access method as described in any one of claims 1 to 18; and / or the NPCA-based channel access method as described in any one of claims 19 to 36.

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