Method and apparatus for channel access in wireless LAN system

Abstract

Various embodiments of the present disclosure relate to a method and an apparatus for channel access in a wireless LAN system. A method performed by an access point (AP) in a wireless local access network (LAN) system according to an embodiment of the present disclosure comprises the steps of: identifying a transmission related to an overlapping basic service set (OBSS) in a primary channel; setting a non-primary channel access (NPCA) time interval for NPCA in a non-primary channel (NPCH); identifying a truncation of the NPCA before expiration of the NPCA time interval; and transmitting, through the NPCH, a control frame related to the truncation of the NPCA.

Description

Method and device for channel access in a wireless LAN system

[0001] The present disclosure relates generally to a wireless LAN system, and more particularly to a method and apparatus for channel access in a wireless LAN system.

[0002] A wireless local area network (WLAN), also known as Wireless Fidelity (Wi-Fi), is a network that allows users to access the Internet via mobile devices and laptops within a certain distance from an access point (AP). WLAN technology continues to evolve with the rise of the Internet and the expansion of the smartphone market, and WRAN is used to provide high-speed data services to entire cities, including schools, airports, hotels, and offices.

[0003] The WiFi Alliance defines WiFi as a wireless local area network (WLAN) product based on the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standards. IEEE 802.11a and b, published in 1997 and 1999 respectively, are standards that utilize the unlicensed bands at 2.4 GHz and 5 GHz, with IEEE 802.11b providing a transmission rate of 11 Mbps and IEEE 802.11a providing a transmission rate of 54 Mbps. IEEE 802.11g applies orthogonal frequency-division multiplexing (OFDM) at 2.4 GHz to provide a transmission rate of 54 Mbps. IEEE 802.11n uses multiple input multiple output OFDM (MIMO-OFDM) to provide a transmission rate of 300 Mbps using four spatial streams. IEEE 802.11n supports channel bandwidths up to 40 MHz, in which case it provides a transmission rate of 600 Mbps.

[0004] Afterwards, the IEEE 802.11ac standard was introduced, which supports up to 160 MHz bandwidth, 8 spatial streams, and a speed of up to 1 Gbit / s, and IEEE 802.11ax, which provides multi-user MIMO (MU-MIMO) in both uplink and downlink and supports spatial frequency reuse, dynamic fragmentation, etc. Afterwards, 802.11be is being studied, which supports up to 320 ultra-wide channels, multi-link operation, 4kQAM, etc., and aims to theoretically implement a speed of 46 Gbps.

[0005] Various embodiments of the present disclosure may provide a method and device for channel access in a wireless LAN system.

[0006] The technical problems to be achieved in various embodiments of the present disclosure are not limited to those mentioned above, and other technical problems not mentioned can be considered by a person having ordinary skill in the art from various embodiments of the present disclosure described below.

[0007] According to one embodiment of the present disclosure, a method performed by an access point (AP) in a wireless LAN (local access network) system can be provided.

[0008] According to one embodiment of the present disclosure, the method may include identifying a transmission associated with an overlapping basic service set (OBSS) on a primary channel.

[0009] According to one embodiment of the present disclosure, the method may include a step of setting an NPCA time interval for non-primary channel access (NPCA) in a non-primary channel (NPCH).

[0010] According to one embodiment of the present disclosure, the method may include a step of identifying a truncation of the NPCA prior to expiration of the NPCA time interval.

[0011] According to one embodiment of the present disclosure, the method may include a step of transmitting a control frame related to the suspension of the NPCA through the NPCH.

[0012] According to one embodiment of the present disclosure, the control frame may include: a More Data subfield set to 0, or a Type subfield set to 01 and a Subtype subfield set to 0001, or a Type subfield set to 01, a Subtype subfield set to 0110, and a Control Frame Extension subfield set to any one of values ​​from 1011 to 1111.

[0013] According to one embodiment of the present disclosure, the Duration field of the control frame is set to 0, and the TA (transmitter address) field or the RA (receiver address) field of the control frame may correspond to a BSSID (basic service set identifier) ​​or an address of the AP.

[0014] According to one embodiment of the present disclosure, the control frame may be: a CF-End frame including a BSSID (TA) field corresponding to an address of the AP and a frame control field including a specific subfield, wherein the specific subfield indicates that the CF-End frame is related to an interruption of the NPCA or that the CF-End frame is for the NPCH, or a CTS (clear to send)-to-Self frame including a RA field corresponding to an address of the AP and a frame control field including a specific subfield, wherein the specific subfield indicates that the CTS-to-Self frame is related to an interruption of the NPCA or that the CTS-to-Self frame is for the NPCH.

[0015] According to one embodiment of the present disclosure, the control frame, which is the CF-End frame or the CTS-to-Self frame, may not change a network allocation vector (NAV) setting corresponding to the primary channel.

[0016] According to one embodiment of the present disclosure, the method may include a step of transmitting a control frame related to the interruption of the NPCA on the primary channel after the interruption of the NPCA on a channel including the primary channel and the NPCH, if the control frame is identified as not being successfully transmitted through the NPCH for a predetermined time.

[0017] According to one embodiment of the present disclosure, the method may include a step of returning to the primary channel before expiration of a basic NAV corresponding to the primary channel after the interruption of the NPCA is identified.

[0018] According to one embodiment of the present disclosure, if an OBSS PPDU (physical layer protocol data unit) or an OBSS TXOP (transmission opportunity) is identified in the NPCH, and the remaining time of the NPCA time interval after expiration of the OBSS PPDU or OBSS TXOP is less than a predefined threshold for a non-primary channel (NPC) TXOP, an interruption of the NPCA can be identified.

[0019] According to one embodiment of the present disclosure, a specific channel for a channel access procedure related to the NPCA may be set up within the NPCH.

[0020] According to one embodiment of the present disclosure, an interruption of the NPCA can be identified when an OBSS management frame is detected on the specific channel.

[0021] According to one embodiment of the present disclosure, if a response to one or more of the transmitted MU-RTS (multi user-request to send), BSRP (buffer status report poll), or basic trigger frame is not received during a priority inter frame space (PIFS) after transmitting one or more of the MU-RTS, BSRP, or basic trigger frame through the NPCH, the interruption of the NPCA can be identified.

[0022] According to one embodiment of the present disclosure, when an interruption of the OBSS TXOP of the primary channel is identified, an interruption of the NPCA can be identified.

[0023] According to one embodiment of the present disclosure, an access point (AP) of a wireless local access network (LAN) system may be provided.

[0024] According to one embodiment of the present disclosure, the AP may include a transceiver; and a processor connected to the transceiver.

[0025] According to one embodiment of the present disclosure, the processor may be configured to: identify a transmission associated with an overlapping basic service set (OBSS) on a primary channel.

[0026] According to one embodiment of the present disclosure, the processor may be configured to: set an NPCA time interval for non-primary channel access (NPCA) in a non-primary channel (NPCH).

[0027] According to one embodiment of the present disclosure, the processor may be configured to: identify a truncation of the NPCA prior to expiration of the NPCA time interval.

[0028] According to one embodiment of the present disclosure, the processor may be configured to transmit a control frame related to the interruption of the NPCA via the NPCH.

[0029] According to one embodiment of the present disclosure, the control frame may include: a More Data subfield set to 0, or a Type subfield set to 01 and a Subtype subfield set to 0001, or a Type subfield set to 01, a Subtype subfield set to 0110, and a Control Frame Extension subfield set to any one of values ​​from 1011 to 1111.

[0030] According to one embodiment of the present disclosure, the Duration field of the control frame is set to 0, and the TA (transmitter address) field or the RA (receiver address) field of the control frame may correspond to a BSSID (basic service set identifier) ​​or an address of the AP.

[0031] According to one embodiment of the present disclosure, the control frame may be: a CF-End frame including a BSSID (TA) field corresponding to an address of the AP and a frame control field including a specific subfield, wherein the specific subfield indicates that the CF-End frame is related to an interruption of the NPCA or that the CF-End frame is for the NPCH, or a CTS (clear to send)-to-Self frame including a RA field corresponding to an address of the AP and a frame control field including a specific subfield, wherein the specific subfield indicates that the CTS-to-Self frame is related to an interruption of the NPCA or that the CTS-to-Self frame is for the NPCH.

[0032] According to one embodiment of the present disclosure, the control frame, which is the CF-End frame or the CTS-to-Self frame, may not change a network allocation vector (NAV) setting corresponding to the primary channel.

[0033] According to one embodiment of the present disclosure, the processor may be configured to: transmit a control frame related to the interruption of the NPCA on the primary channel after the interruption of the NPCA on a channel including the primary channel and the NPCH, if the control frame is identified as not being successfully transmitted through the NPCH for a predetermined period of time.

[0034] According to one embodiment of the present disclosure, the processor may be configured to: return to the primary channel before expiration of a basic NAV corresponding to the primary channel after an interruption of the NPCA is identified.

[0035] According to one embodiment of the present disclosure, if an OBSS PPDU (physical layer protocol data unit) or an OBSS TXOP (transmission opportunity) is identified in the NPCH, and the remaining time of the NPCA time interval after expiration of the OBSS PPDU or OBSS TXOP is less than a predefined threshold for a non-primary channel (NPC) TXOP, an interruption of the NPCA can be identified.

[0036] According to one embodiment of the present disclosure, a specific channel for a channel access procedure related to the NPCA may be set up within the NPCH.

[0037] According to one embodiment of the present disclosure, an interruption of the NPCA can be identified when an OBSS management frame is detected on the specific channel.

[0038] According to one embodiment of the present disclosure, a method performed by a STA (station) in a wireless LAN (local access network) system can be provided.

[0039] According to one embodiment of the present disclosure, the method may include identifying a transmission associated with an overlapping basic service set (OBSS) on a primary channel.

[0040] According to one embodiment of the present disclosure, the method may include a step of setting an NPCA time interval for non-primary channel access (NPCA) in a non-primary channel (NPCH).

[0041] According to one embodiment of the present disclosure, the method may include receiving a control frame related to truncation of the NPCA via the NPCH.

[0042] According to one embodiment of the present disclosure, the method may include a step of stopping the NPCA before expiration of the NPCA time interval based on the control frame.

[0043] According to one embodiment of the present disclosure, a STA (station) of a wireless LAN (local access network) system can be provided.

[0044] According to one embodiment of the present disclosure, the STA may include a transceiver; and a processor connected to the transceiver.

[0045] According to one embodiment of the present disclosure, the processor may be configured to: identify a transmission associated with an overlapping basic service set (OBSS) on a primary channel.

[0046] According to one embodiment of the present disclosure, the processor may be configured to: set an NPCA time interval for non-primary channel access (NPCA) in a non-primary channel (NPCH).

[0047] According to one embodiment of the present disclosure, the processor may be configured to: receive a control frame related to truncation of the NPCA via the NPCH.

[0048] According to one embodiment of the present disclosure, the processor may be configured to: stop the NPCA before expiration of the NPCA time interval based on the control frame.

[0049] The various embodiments of the present disclosure described above are only some of the preferred embodiments of the present disclosure, and various embodiments reflecting the technical features of the various embodiments of the present disclosure can be derived and understood by a person having ordinary skill in the art based on the detailed description to be described below.

[0050] Various embodiments of the present disclosure may provide a method and device for channel access in a wireless LAN system.

[0051] The effects that can be obtained from various embodiments of the present disclosure are not limited to the effects mentioned above, and other effects not mentioned can be clearly derived and understood by a person having ordinary skill in the art based on the detailed description below.

[0052] The accompanying drawings are intended to aid in understanding various embodiments of the present disclosure, and provide various embodiments of the present disclosure together with detailed descriptions. However, the technical features of the various embodiments of the present disclosure are not limited to specific drawings, and the features disclosed in each drawing may be combined with each other to form new embodiments. Reference numerals in each drawing represent structural elements.

[0053] FIG. 1 is a diagram illustrating an example of a wireless communication network to which various embodiments of the present disclosure can be applied.

[0054] FIG. 2 is a diagram illustrating an example of the structure of an electronic device performing WLAN connection to which various embodiments of the present disclosure are applicable.

[0055] FIG. 3 is a diagram illustrating an example of a link setup process of a general wireless LAN to which various embodiments of the present disclosure are applicable.

[0056] FIG. 4 is a diagram illustrating an example of a hidden node and an exposed node to which various embodiments of the present disclosure are applicable, and an example of an RTS and a CTS for solving the problem of the hidden node and the exposed node.

[0057] FIG. 5 is a diagram illustrating an example of a frame structure used in an IEEE 802.11 system to which various embodiments of the present disclosure are applicable.

[0058] FIG. 6 is a diagram illustrating an example of NAV settings to which various embodiments of the present disclosure can be applied.

[0059] FIG. 7 is a diagram illustrating an example of a TXOP to which various embodiments of the present disclosure can be applied.

[0060] FIG. 8 is a diagram illustrating an example of a channel connection to which various embodiments of the present disclosure can be applied.

[0061] FIG. 9a is a diagram illustrating an example of an implicit notification method of NTC according to one embodiment of the present disclosure.

[0062] FIG. 9b is a diagram illustrating an example of an implicit notification method of NTC according to one embodiment of the present disclosure.

[0063] FIG. 9c is a diagram illustrating an example of an implicit notification method of NTC according to one embodiment of the present disclosure.

[0064] FIG. 9d is a diagram illustrating an example of an implicit notification method of NTC according to one embodiment of the present disclosure.

[0065] FIG. 9e is a diagram illustrating an example of an implicit notification method of NTC according to one embodiment of the present disclosure.

[0066] FIG. 9f is a diagram illustrating an example of an implicit notification method of NTC according to one embodiment of the present disclosure.

[0067] FIG. 9g is a diagram illustrating an example of an implicit notification method of NTC according to one embodiment of the present disclosure.

[0068] FIG. 10 is a diagram showing an example of an NTC format using CF-End according to one embodiment of the present disclosure.

[0069] FIG. 11 is a diagram illustrating an example of an NTC format using CTS-to-Self according to one embodiment of the present disclosure.

[0070] FIG. 12 is a diagram illustrating an example of an operation related to an NPC TXOP within a section for an NPCA operation according to one embodiment of the present disclosure.

[0071] FIG. 13 is a diagram illustrating an example of an operation related to an NPC TXOP within a section for NPCA operation according to one embodiment of the present disclosure.

[0072] FIG. 14 is a diagram illustrating an example of an operation related to an NPC TXOP within a section for an NPCA operation according to one embodiment of the present disclosure.

[0073] FIG. 15 is a diagram illustrating an example of an operation related to an NPC TXOP within a section for an NPCA operation according to one embodiment of the present disclosure.

[0074] FIG. 16 is a diagram illustrating an example of an operation related to an NPC TXOP within a section for an NPCA operation according to one embodiment of the present disclosure.

[0075] FIG. 17 is a diagram illustrating an example of an operation related to an NPC TXOP within a section for an NPCA operation according to one embodiment of the present disclosure.

[0076] FIG. 18 is a diagram illustrating an example of an operation related to an NPC TXOP within a section for an NPCA operation according to one embodiment of the present disclosure.

[0077] FIG. 19 is a diagram illustrating an example of an operation related to an NPC TXOP within a section for NPCA operation according to one embodiment of the present disclosure.

[0078] FIG. 20 is a diagram illustrating an example of an operation related to an NPC TXOP within a section for an NPCA operation according to one embodiment of the present disclosure.

[0079] FIG. 21 illustrates an example of the operation of an AP according to one embodiment of the present disclosure.

[0080] FIG. 22 illustrates an example of the operation of an STA according to one embodiment of the present disclosure.

[0081] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the attached drawings.

[0082] In describing the embodiments, descriptions of technical details that are well known in the technical field to which the present disclosure pertains and are not directly related to the present disclosure will be omitted. This is to ensure that the gist of the present disclosure is conveyed more clearly without obscuring it by omitting unnecessary explanations.

[0083] For the same reason, some components in the attached drawings are exaggerated, omitted, or schematically depicted. Furthermore, the dimensions of each component do not entirely reflect its actual size. Identical or corresponding components in each drawing are assigned the same reference numbers.

[0084] The advantages and features of the present disclosure, and methods for achieving them, will become clearer with reference to the embodiments described below in detail together with the accompanying drawings. However, the present disclosure is not limited to the embodiments disclosed below and may be implemented in various different forms. The embodiments of the present disclosure are provided only to ensure that the present disclosure is complete and to fully inform those skilled in the art of the scope of the disclosure, and the present disclosure is defined only by the scope of the claims. Like reference numerals refer to like elements throughout the specification.

[0085] At this time, it will be understood that each block of the processing flowchart drawings and combinations of the flowchart drawings can be performed by computer program instructions. These computer program instructions can be installed in a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing equipment, so that the instructions executed by the processor of the computer or other programmable data processing equipment create a means for performing the functions described in the flowchart block(s). These computer program instructions can also be stored in a computer-available or computer-readable memory that can direct a computer or other programmable data processing equipment to implement the functions in a specific manner, so that the instructions stored in the computer-available or computer-readable memory can also produce a manufactured item that includes an instruction means for performing the functions described in the flowchart block(s).

[0086] Since the computer program instructions may be installed on a computer or other programmable data processing device, a series of operational steps may be performed on the computer or other programmable data processing device to create a computer-executable process, so that the instructions that cause the computer or other programmable data processing device to perform the steps for performing the functions described in the flowchart block(s) may also be able to provide steps for performing the functions described in the flowchart block(s).

[0087] Additionally, each block may represent a module, segment, or portion of code that contains one or more executable instructions for performing a specific logical function(s). It should also be noted that in some alternative implementation examples, the functions described in the blocks may occur out of order. For example, two blocks depicted in succession may actually be executed substantially concurrently, or the blocks may sometimes be executed in reverse order, depending on their respective functions.

[0088] Here, the term '~ unit' used in this embodiment means software or hardware components such as FPGA (field programmable gate array) or ASIC (application specific integrated circuit), and the '~ unit' performs certain roles. However, the '~ unit' is not limited to software or hardware. The '~ unit' may be configured to be on an addressable storage medium and may be configured to play one or more processors. Accordingly, according to some embodiments, the '~ unit' includes components such as software components, object-oriented software components, class components, and task components, processes, functions, properties, procedures, subroutines, segments of program code, drivers, firmware, microcode, circuits, data, databases, data structures, tables, arrays, and variables. The functions provided within the components and '~ units' may be combined into a smaller number of components and '~ units' or further separated into additional components and '~ units'. Additionally, the components and '~parts' may be implemented to activate one or more CPUs within the device or secure multimedia card. Furthermore, according to some embodiments, the '~parts' may include one or more processors.

[0089] The exemplary embodiments are described below solely for simplicity with respect to wireless LAN systems. It should be understood that the exemplary embodiments are equally applicable to other wireless networks (e.g., cellular networks, pico-networks, femto-networks, satellite networks), as well as systems that utilize signals of one or more wired standards or protocols (e.g., Ethernet and / or HomePlug, PLC standards). As used herein, the terms WLAN and Wi-Fi® may include communications governed by the IEEE 802.11 family of standards, BLUETOOTH®, HiperLAN (a set of wireless standards primarily used in Europe and comparable to the IEEE 802.11 standards), and other technologies with relatively short radio ranges. Accordingly, the terms WLAN and WiFi may be used interchangeably herein. Additionally, while described below with respect to an infrastructure WLAN system including one or more APs and a plurality of wireless stations (STAs), the exemplary embodiments are equally applicable to other WLAN systems including, for example, multiple WLANs, peer-to-peer (or independent basic service set) systems, Wi-Fi Direct systems, and / or hotspots.

[0090] Additionally, while the present disclosure describes the exchange of data frames between wireless devices, the exemplary embodiments may be applied to the exchange of any data unit, packet, and / or frame between wireless devices. Thus, the term frame may include any frame, packet, or data unit, such as, for example, protocol data units (PDUs), media access control (MAC) protocol data units (MPDUs), and physical layer convergence procedure (PLCP) protocol data units. The term A-MPDU may mean aggregated MPDUs. A wireless local area network, or WLAN network, below may be a network implementing at least one of the IEEE 802.11 family of wireless communication protocol standards, such as those defined by the IEEE 802.11-2016 standard or amendments thereto (including, but not limited to, 802.11ah, 802.11ad, 802.11ay, 802.11ax, 802.11az, 802.11ba, and 802.11be).

[0091] In the following description, numerous specific details are set forth, such as examples of specific components, circuits, and processes, to provide a thorough understanding of the present disclosure. The term "connected," as used herein, means directly connected or connected via one or more intervening components or circuits. The term "connected AP" refers to an access point with which a given wireless station is currently associated and / or connected (e.g., there is an established communications channel or link between the access point and the given wireless station). Furthermore, in the following description and for purposes of explanation, specific nomenclature is set forth to provide a thorough understanding of the exemplary embodiments. However, it will be apparent to one skilled in the art that such specific details may not be necessary to practice the exemplary embodiments. In other instances, well-known circuits and devices are shown in block diagram form to avoid obscuring the present disclosure.

[0092] The operating principles of the present disclosure are described in detail below with reference to the attached drawings. In the following description of the present disclosure, detailed descriptions of related known functions or configurations will be omitted if they are deemed to unnecessarily obscure the gist of the present disclosure. Furthermore, the terms described below are defined based on the functions of the present disclosure and may vary depending on the intent or custom of the user or operator. Therefore, their definitions should be based on the overall content of this specification.

[0093] FIG. 1 is a diagram illustrating an example of a wireless communication network to which various embodiments of the present disclosure can be applied.

[0094] The wireless communication network (100) may be an example of a wireless local area network (LAN), such as a Wi-Fi network. The wireless communication network (100) may include a plurality of wireless communication devices, such as an access point (AP) 102 and a plurality of stations (STAs) 104. Although only one AP (102) is illustrated, the wireless communication network (100) may also include a plurality of APs (102).

[0095] An STA is a logical entity that includes a MAC and a physical layer interface to a wireless medium, and includes an AP and a non-AP STA (Non-AP station). Among the STAs, a portable terminal operated by a user is a Non-AP STA, and when simply referred to as an STA, it also refers to a Non-AP STA. Hereinafter, an STA may refer to a non-AP STA. Each of the STAs (104) may be referred to as a terminal or a device. The term 'terminal' or 'device' used in this specification may be referred to as a mobile station (MS), user equipment (UE), user terminal (UT), wireless terminal, access terminal (AT), terminal, subscriber unit, subscriber station (SS), wireless device, wireless communication device, wireless transmit / receive unit (WTRU), mobile node, mobile, or other terms. Various embodiments of the terminal may include a cellular telephone, a smart phone having wireless communication capabilities, a personal digital assistant (PDA) having wireless communication capabilities, a wireless modem, a portable computer having wireless communication capabilities, a photographic device such as a digital camera having wireless communication capabilities, a gaming device having wireless communication capabilities, a music storage and playback appliance having wireless communication capabilities, an Internet appliance capable of wireless Internet access and browsing, as well as portable units or terminals incorporating combinations of such functions. In addition, the terminal may include, but is not limited to, a machine-to-machine (M2M) terminal, a machine type communication (MTC) terminal / device. In the present specification, the terminal may also be referred to as an electronic device or simply a device.

[0096] An AP (102) is an entity that provides access to a distribution system (DS) via a wireless medium to its associated STAs. An AP may also be called a centralized controller, a base station (BS), a Node-B, a base transceiver system (BTS), or a site controller.

[0097] An exemplary coverage area (106) of an AP (102) that may represent a basic service area (BSA) of a wireless communication network (100) is illustrated. The AP (102) periodically broadcasts beacon frames (beacon frames may be used interchangeably with beacon) containing a basic service set identifier (BSSID) to enable any STAs (104) within the wireless range of the AP (102) to associate or re-associate with the AP (102) and establish or maintain a separate communication link (108) (or may be referred to as a Wi-Fi link) with the AP (102). The AP (102) may provide access to external networks for various STAs (104) within the WLAN via the separate communication links (108).

[0098] A single AP (102) and an associated set of STAs (104) may be referred to as a basic service set (BSS) managed by the individual AP (102). The BSS may be identified to users by a service set identifier (SSID), as well as to other devices by the BSSID, which may be the MAC address of the AP (102).

[0099] BSS can be categorized into infrastructure BSS and independent BSS (IBSS). The BSS illustrated in Figure 1 is an IBSS, but an infrastructure BSS (not shown) can also be established. An infrastructure BSS includes one or more STAs and an AP. In principle, communication between non-AP STAs in an infrastructure BSS occurs via the AP. However, if a direct link is established between non-AP STAs, direct communication between non-AP STAs is also possible.

[0100] Multiple infrastructure BSSs can be interconnected via a DS. Multiple BSSs connected via a DS are called an extended service set (ESS). STAs within an ESS can communicate with each other, and within the same ESS, STAs can seamlessly move from one BSS to another while maintaining seamless communication.

[0101] A DS is a mechanism that connects multiple APs. It doesn't necessarily have to be a network, and there are no restrictions on its form as long as it can provide a certain distribution service. For example, a DS could be a wireless network, such as a mesh network, or a physical structure that connects APs.

[0102] Additionally, the AP (102) and the STA (104) may be referred to as AP-MLD (access point multi-link device) and STA-MLD, respectively. This may mean that the AP and the STA can support multi-link operation.

[0103] Below is an example of a hierarchical structure according to the 802.11 standard.

[0104] The 802.11 standard document is developing the MAC and PHY protocols corresponding to Wi-Fi wireless access technology. The data link layer (DLL) includes the MAC sublayer, which is responsible for media access control, and receives packets from the upper layer, 802.1X Port Filtering, through the MAC_SAP interface, and configures them into IEEE 802.11 MAC frames and transmits them to the physical layer. The physical layer includes the PLCP (physical layer convergence procedure) sublayer and the PDM (physical medium dependent) sublayer, and the PLCP sublayer is responsible for configuring the IEEE 802.11 MAC frame configured in the MAC sublayer into a PLCP frame. The PLCP frame is then transmitted to the opposite terminal through the PMD sublayer.

[0105] Various management frames that manage Wi-Fi wireless access are not transmitted at the upper layer of 802.1X. These management frames are transmitted as requests and responses between the SMEs (station management entities) located within each terminal. The SME is a layer-independent entity that may exist in a separate management plane or may appear to be off to the side. For example, if an AP wants to form a BSS, the AP instructs the transmission of a beacon through the MLME_SAP interface, namely, the MLME-START.reques and MLME-START.confirm primitives. If an STA wants to associate with the AP, the STA instructs the transmission of an association Request / Response frame through the MLME-ASSOCIATE.request, MLME-ASSOCIATE.response, MLME-ASSOCIATE.confirm, and MLME-ASSOCIATE.indication primitives. Meanwhile, if SME wants to set operating parameter values ​​related to the physical layer, it can set various physical layer parameter values ​​through the PLCP_SAP interface.

[0106] FIG. 2 is a diagram illustrating an example of the structure of an electronic device performing WLAN connection to which various embodiments of the present disclosure are applicable.

[0107] Referring to FIG. 2, an electronic device (200) may be connected to an AP (210), and the electronic device (200) may include a processor (230) and a communication module (220). The electronic device (200) may be the STA (104) of FIG. 1, in which case the electronic device (200) may be connected to the AP (210) as illustrated. Alternatively, the electronic device (200) may be the AP (102) of FIG. 1, in which case the electronic device may be connected to the STA (104) and / or another AP as illustrated in FIG. 1.

[0108] The communication module (220) can receive a communication signal from the outside or transmit a communication signal to the outside based on a Wi-Fi communication method (for example, IEEE Std 802.11TM). For example, the communication module (220) can operate based on IEEE 802.11ac, 802.11ax, 802.11be, or 802.11bn among Wi-Fi communication methods, and in particular, IEEE 802.11be or 802.11bn has improved performance by supporting a wider bandwidth, higher data throughput, and shorter delay time compared to IEEE 802.11ax.

[0109] The communication module (220) may include a transceiver (224) for transmitting and receiving data with an external device and a communication processor (222) (e.g., a communication processor (not shown) or a short-range wireless communication module (e.g., a Wi-Fi chipset)). According to various embodiments, the communication module (220) may further include a memory.

[0110] According to various embodiments, the transceiver (224) may convert a baseband transmit signal into a wireless signal or may convert a received wireless signal into a baseband receive signal.

[0111] According to various embodiments, the communication module (220) may further include, in addition to the transceiver (224) and the communication processor (222), components for OFDM or OFDMA (orthogonal frequency division multiple access), for example, a modulator, a digital-analog converter (D / A converter), a frequency converter, an A / D converter, an amplifier, and / or a demodulator.

[0112] Although not shown, according to various embodiments, the electronic device (200) may include at least one antenna module that is electrically connected to the communication module of the AP (210) and supports a communication protocol and / or frequency band supported by the communication module of the AP (210).

[0113] The communication processor (222) may control the transceiver (224) to form a communication connection with the AP (210). For example, the communication connection may include a Wi-Fi network. For example, the communication processor (222) may control the transceiver (224) to form a wireless connection with the AP (200) using a 2.4 GHz, 5 GHz, or 6 GHz band WLAN standard such as IEEE 802.11ac, 802.11ax, 802.11be, or 802.11bn. Alternatively, the communication processor (222) may control the transceiver (191) to form a wireless connection with the AP (210) using a 60 GHz band WLAN standard such as IEEE 802.11ad or 802.11ay. Additionally, a method of communicating between an electronic device (200) and an AP (210) using the WLAN standard may be referred to as a communication method based on the STA mode.

[0114] According to various embodiments, the processor (230) may include an application processor. The processor (230) may perform a specified operation of the electronic device (200) or control other hardware (e.g., a communication module (220)) to perform a specified operation.

[0115] According to various embodiments, the AP (210) may support an operation of transmitting packets to an external network and / or an operation of the plurality of electronic devices receiving packets from an external network based on a connection between a plurality of electronic devices (e.g., the electronic device (200)) and an external network (e.g., the Internet, an external LAN, or a cellular network).

[0116] For example, the AP (210) may be a wireless router. The AP (210) may be a dedicated wireless router or a general-purpose device supporting mobile hotspot functionality, and there are no limitations on its implementation. For example, the AP (210) may include the same components as the electronic device (200), such as a processor and / or a communication module. Furthermore, the AP (210) may transmit and receive data to and from an external device, such as a server. For example, the AP (210) may transmit at least a portion of the data received from the server to the electronic device (200).

[0117] If the electronic device (200) of FIG. 2 corresponds to the AP (102), the electronic device (200) may include a separate communication module for connection with an external network, although not shown. This communication module may be controlled by the processor (230) or by a separate processor. The separate communication module may include a transceiver and a processor, and may also include memory. In addition, the electronic device (200) may include a separate antenna module or wired connection device for connection with an external network.

[0118] FIG. 3 is a diagram illustrating an example of a link setup process of a general wireless LAN to which various embodiments of the present disclosure are applicable.

[0119] For an STA to set up a link and transmit and receive data on a network, it must first discover the network, perform authentication, establish an association, and complete security authentication procedures. The link setup process can also be referred to as the session initiation process or session setup process. Furthermore, the discovery, authentication, association, and security setup processes of the link setup process can be collectively referred to as the association process.

[0120] Referring to FIG. 3, an STA (300) can perform a network discovery operation. The network discovery operation may include a scanning operation of the STA (300). That is, in order for the STA (300) to access a network, it must search for a network it can participate in. Before joining a wireless network, the STA (300) must identify a compatible network. The process of identifying networks existing in a specific area is called scanning.

[0121] There are two types of scanning methods: active scanning and passive scanning. In active scanning, an STA (300) performing scanning transmits a probe request frame (322) to search for APs in the vicinity while moving between channels and waits for a response. A responder transmits a probe response frame (324) to the STA that transmitted the probe request frame in response to the probe request frame. Here, the responder may be an AP or STA that last transmitted a beacon frame in the BSS of the channel being scanned. In FIG. 3, an example of a BSS that becomes a responder is shown because an AP (310) transmits a beacon frame (320), and in an IBSS, STAs within the IBSS take turns transmitting beacon frames, so the responder is not constant. For example, if an STA transmits a probe request frame on channel 1 and receives a probe response frame on channel 1, the STA can store BSS-related information included in the received probe response frame and move to the next channel to perform scanning in the same manner.

[0122] The scanning operation can also be performed in a passive scanning manner. In passive scanning, the STA performing the scanning moves through channels and detects beacon frames. A beacon frame is one of the management frames in IEEE 802.11, and is periodically transmitted to announce the presence of a wireless network and to enable the STA performing the scanning to find the wireless network and participate in the wireless network. FIG. 3 illustrates an example of a BSS in which an AP (310) periodically transmits a beacon frame (320) to an STA (300), and in an IBSS, STAs within the IBSS take turns transmitting beacon frames. When the STA performing the scanning receives a beacon frame, it stores information about the BSS included in the beacon frame and moves to another channel, recording the beacon frame information on each channel. Comparing active and passive scanning, active scanning has the advantage of lower delay and power consumption than passive scanning.

[0123] After the STA (300) discovers the network, an authentication process may be performed. This authentication process may be referred to as the first authentication process to clearly distinguish it from the security setup operation (350) described below. The authentication process includes a process in which the STA (300) transmits an authentication request frame (330) to the AP (310), and in response, the AP (310) transmits an authentication response frame (332) to the STA (300). The authentication frame used for the authentication request / response corresponds to a management frame.

[0124] The authentication frame may include information such as an authentication algorithm number, an authentication transaction sequence number, a status code, a challenge text, a Robust Security Network (RSN), and a Finite Cyclic Group. These are just some examples of information that may be included in an authentication request / response frame, and may be replaced with other information or include additional information.

[0125] The AP (310) may determine whether to allow authentication for the STA based on information included in the received authentication request frame. The AP (310) may provide the result of the authentication process to the STA (300) via an authentication response frame.

[0126] After the STA is successfully authenticated, an association process can be performed. The association process includes a process in which the STA (300) transmits an association request frame (340) to the AP (310), and in response, the AP (310) transmits an association response frame (342) to the STA (300).

[0127] For example, the association request frame may include information related to various capabilities, such as beacon listen interval, SSID, supported rates, supported channels, robust security network (RSN), mobility domain, supported operating classes, traffic indication map broadcast request, and interworking service capabilities.

[0128] For example, the association response frame may include information related to various capabilities, status codes, association ID (AID), supported rates, enhanced distributed channel access (EDCA) parameter sets, received channel power indicator (RCPI), received signal to noise indicator (RSNI), mobility domains, timeout interval (association comeback time), overlapping BSS scan parameters, TIM broadcast response, QoS maps, etc.

[0129] These are just some examples of information that may be included in a request / response frame, and may be replaced by other information or include additional information.

[0130] Although not shown, after the STA successfully associates with the network, a security setup process may be performed. The security setup process may be referred to as an authentication process via a robust security network association (RSNA) request / response, the authentication process (330) may be referred to as a first authentication process, and the security setup process may also be referred to as an authentication process.

[0131] The security setup process may include, for example, a private key setup process through a four-way handshaking using an extensible authentication protocol over LAN (EAPOL) frame, or may be performed according to a security method not defined in the IEEE 802.11 standard.

[0132] Below we describe the media access control protocol provided by 802.11.

[0133] In wireless LAN systems based on IEEE 802.11, the basic access mechanism of MAC is based on the distributed coordination function (DCF) that utilizes the carrier sense multiple access with collision avoidance (CSMA / CA) method. There are two methods for detecting carriers in DCF: physical carrier sense and virtual carrier sense. Physical carrier sense is a method in which the physical layer detects the channel status and notifies the MAC layer, and virtual carrier sense is a method in which the channel occupancy time is broadcast to neighboring stations to reserve the channel in advance. An STA or AP that has secured a transmission channel records and transmits this channel occupancy time within the RTS or / and CTS or data frame. Other STAs that receive this determine that the channel is busy during this time and do not compete for the channel, thereby avoiding collisions.

[0134] The physical carrier sensing method basically adopts a listen-before-talk access mechanism, and according to this type of access mechanism, the AP and / or STA can perform a clear channel assessment (CCA) to sense the wireless channel or carrier or medium for a predetermined time period before starting transmission. The predetermined time period is called an inter frame space (IFS) and can vary depending on the priority of the traffic to be transmitted. That is, the priority can be determined by the length of the time period, and the higher the priority packet, the shorter the time period can be.

[0135] The above IFS may include a short IFS (SIFS), a priority IFS (PIFS, a point coordination function (PCF) IFS), a distributed (coordination function) IFS (DIFS), an arbitration IFS (AIFS), etc. The SIFS is the shortest time interval and may be mainly used as a waiting time for control information. The PIFS is a medium-length time interval and may be for a packet with a medium priority (PIFS = SIFS+1 slot time). The DIFS is the longest time interval compared to the SIFS and PIFS, has a low priority, and may be mainly used as a waiting time for checking whether a channel is in use (DIFS=SIFS+2 slot time). That is, for example, an STA that wishes to perform transmission may listen to whether a channel is in use (or detect the channel) during the DIFS period.

[0136] Based on the sensing result, if the medium is determined to be in an idle state, the AP and / or STA initiate frame transmission through the medium. On the other hand, if the medium is detected to be in an occupied state, the AP and / or STA may not initiate its own transmission, but may wait for a delay period (e.g., a random backoff period) for medium access before attempting frame transmission. By applying a random backoff period, multiple STAs are expected to attempt frame transmission after waiting for different periods of time, thereby minimizing collisions.

[0137] However, since this DCF method does not consider the priority between STAs, it has a problem in that it is difficult to support various types of data transmission and QoS (Quality of Service), so the hybrid coordination function (HCF) was introduced. HCF is based on the DCF and the point coordination function (PCF). PCF is a polling-based synchronous access method that periodically polls all receiving APs and / or STAs so that they can receive data frames. HCF includes EDCA (enhanced distributed channel access), which is a contention-based channel access method, and HCCA (HCF controlled channel access), which is a contention-free method using a polling mechanism. In addition, HCF includes a medium access mechanism to improve the QoS of WLAN, and can transmit QoS data in both a contention period (CP) and a contention-free period (CFP).

[0138] FIG. 4 is a diagram illustrating an example of a hidden node and an exposed node to which various embodiments of the present disclosure are applicable, and an example of an RTS and a CTS for solving the problem of the hidden node and the exposed node.

[0139] Figure 4 (a)(400) is an example of a hidden node. When STA A and STA B are communicating and STA C has information to transmit, STA A may determine that the medium is idle when performing carrier sensing before STA C sends data to STA B, even though STA A is transmitting the information to STA B. This is because STA A's transmission (i.e., medium occupancy) may not be sensed at STA C's location. In this case, STA B receives information from STA A and STA C simultaneously, resulting in a collision. In this case, STA A can be said to be a hidden node of STA C.

[0140] (b)(410) is an example of an exposed node. In a situation where STA B is transmitting data to STA A, STA C may have information to transmit to STA D. In this case, if STA C performs carrier sensing, it may determine that the medium is occupied due to the transmission of STA B. Accordingly, STA C must wait until the medium becomes idle even if it has information to transmit to STA D. However, in reality, STA A is outside the transmission range of STA C, so the transmission from STA C and the transmission from STA B may not collide from the perspective of STA A, and thus STA C unnecessarily waits until STA B stops transmitting. In this case, STA C can be called an exposed node of STA B.

[0141] In order to effectively utilize the collision avoidance mechanism in the above situation, short signaling packets such as RTS (request to send) and CTS (clear to send) can be utilized. An STA that wishes to transmit data transmits an RTS to an STA that will receive the data, and the receiving STA that receives the RTS responds to the transmitting STA with a CTS frame. The RTS and / or CTS between two STAs can be overheard by surrounding STA(s), allowing the surrounding STA(s) to consider whether information should be transmitted between the two STAs.

[0142] (c)(420) is an example of a method for solving the hidden node problem. Assume that both STA A and STA C want to transmit data to STA B. When STA A transmits an RTS to STA B, STA B transmits a CTS to STA A. STA C, which overhears the RTS and CTS, delays its medium access until STA A and STA B finish transmitting data, thereby avoiding collisions.

[0143] (d)(430) is an example of a method for solving the exposed node problem. STA B, which wants to transmit data to STA A, transmits an RTS, and STA A, which is to receive the data, can respond to the RTS by transmitting a CTS. In this case, if STA C receives only the RTS transmitted by STA B and does not receive the CTS transmitted by STA A, STA C can know that STA A is outside the carrier sensing area of ​​STA C. In this case, STA C can determine that no collision will occur even if it transmits data to another STA (e.g., STA D), and can transmit the data.

[0144] FIG. 5 is a diagram illustrating an example of a frame structure used in an IEEE 802.11 system to which various embodiments of the present disclosure are applicable.

[0145] The PPDU (physical layer protocol data unit) format can be composed of a short training field (STF), a long training field (LTF), a SIGNAL (SIG) field, and a data field. The most basic (e.g., non-HT (high throughput)) PPDU frame format can be composed of only the legacy-STF (L-STF), legacy-LTF (L-LTF), a SIG field, and a data field.

[0146] STF can be used for frame timing acquisition, automatic gain control (AGC), diversity detection, and coarse frequency / time synchronization. LTF can be used for fine frequency / time synchronization and channel estimation. The STF and LTF can be collectively called the PLCP preamble, which is a signal for OFDM physical layer synchronization and channel estimation.

[0147] The SIG field can be used to transmit control information for demodulation and decoding of the data field. The SIG field can include information about the data rate and data length. Additionally, the SIG field can include a parity bit, a SIG TAIL bit, etc.

[0148] The data field may include a SERVICE field, a physical layer service data unit (PSDU), a PPDU TAIL bit, and, if necessary, padding bits. Some bits of the SERVICE field may be used for a descrambler at the receiver. The PSDU corresponds to an MPDU (mac protocol data unit) defined at the MAC layer and may contain data generated / used by upper layers. The PPDU TAIL bit may be used to return the encoder to a 0 state. The padding bit may be used to adjust the length of the data field to a predetermined unit.

[0149] MPDU is defined according to various MAC frame formats, and a basic MAC frame consists of a MAC header, frame body, and FCS (frame check sequence). MAC frame is composed of MPDU and can be transmitted / received through PSDU of the data part of PPDU format.

[0150] The MAC header is defined as an area that includes a frame control field, a duration / ID field, an address 1 field, an address 2 field, an address 3 field, a sequence control field, an address 4 field, a QoS control field, and an HT control field.

[0151] The Frame Control field contains information about the characteristics of the corresponding MAC frame. The Segment / Identifier field may be implemented to have different values ​​depending on the type and subtype of the corresponding MAC frame.

[0152] The Address 1 field to the Address 4 field are used to indicate the BSSID, source address (SA), destination address (DA), transmitting address (TA) indicating the transmitting STA address, and receiving address (RA) indicating the receiving STA address.

[0153] The sequence control field is set to include a sequence number and a fragment number. The sequence number can indicate the sequence number assigned to the corresponding MAC frame. The fragment number can indicate the number of each fragment of the corresponding MAC frame.

[0154] The QoS Control field contains information related to QoS. The QoS Control field may be included when the Subtype subfield indicates a QoS data frame. The HT Control field contains control information related to HT and / or VHT transmission and reception techniques.

[0155] The frame body is defined as the MAC payload, contains the data to be transmitted from the upper layer, and has a variable size. For example, the maximum MPDU size is 11,454 octets, and the maximum PPDU size can be 5.484 ms.

[0156] FCS is defined as a MAC footer and is used to detect errors in MAC frames.

[0157] The first three fields (Frame Control, Segment / Identifier, and Address 1) and the last field (FCS) constitute the minimum frame format and are present in all frames. The remaining fields may only be present in certain frame types.

[0158] Below is a description of the network allocation vector (NAV) used in wireless LAN networks.

[0159] As mentioned above, the CSMA / CA mechanism includes virtual carrier sensing in addition to physical carrier sensing, in which the AP and / or STA directly sense the medium. Virtual carrier sensing is intended to address potential issues in medium access, such as the hidden node problem. For virtual carrier sensing, the MAC of the wireless LAN system can utilize NAV. NAV is a value that indicates to other APs and / or STAs the remaining time until the medium becomes available, by the AP and / or STA currently using or authorized to use the medium. Therefore, the value set as NAV corresponds to the period during which the medium is scheduled to be used by the AP and / or STA transmitting the frame, and the STA receiving the NAV value is prohibited from accessing the medium during the period. NAV can be set, for example, according to the value of the duration field of the MAC header of the frame.

[0160] FIG. 6 is a diagram illustrating an example of NAV settings to which various embodiments of the present disclosure can be applied.

[0161] Referring to FIG. 6, a source STA (source STA, 600) transmits an RTS frame after DIFS, and a destination (destination) (610) transmits a CTS frame after SIFS. The destination STA designated as the receiver through the RTS frame does not set an NAV. Some of the remaining STAs (620) may receive the RTS frame and set an NAV (630), and some may receive the CTS frame and set an NAV (640).

[0162] If a CTS frame (e.g., PHY-RXSTART.indication primitive) is not received within a certain period from the time when the RTS frame is received (e.g., the time when the MAC receives the PHY-RXEND.indication primitive corresponding to the RTS frame), STAs that have set or updated the NAV through the RTS frame may reset the NAV (e.g., to 0). The certain period may be (2*aSIFSTime + CTS_Time + aRxPHYStartDelay + 2*aSlotTime). The CTS_Time may be calculated based on the length of the CTS frame and the data rate indicated by the RTS frame. The certain period may be a NAVTimeout period.

[0163] In Fig. 6, for convenience, setting or updating NAV through an RTS frame or a CTS frame is illustrated, but NAV setting / resetting / updating may also be performed based on various other frames, such as a non-HT PPDU, HT PPDU, VHT PPDU, or an interval field of a HE PPDU (for example, an interval field in a MAC header of a MAC frame).

[0164] 802.11ax also introduces basic NAV and intra-BSS NAV. Basic NAV is always set by frames transmitted by APs or STAs other than itself (mandatory), and intra-BSS NAV can be optionally set by frames transmitted from the BSS to which the AP or STA belongs. An AP or STA can access the medium when both NAV timers have expired (or after all NAV time intervals have elapsed).

[0165] Below, we describe TXOP (transmission opportunity). TXOP is a new feature introduced in the 802.11e MAC to ensure QoS and improve channel utilization. To ensure QoS, TXOP can be used to assign priority transmission opportunities when two or more packets fall into the same access category (AC).

[0166] FIG. 7 is a diagram illustrating an example of a TXOP to which various embodiments of the present disclosure can be applied.

[0167] STAs participating in QoS transmission can obtain TXOPs, which allow them to transmit traffic for a certain period of time, using two channel access methods: EDCA and HCCA. TXOPs can be acquired either by successfully competing in EDCA or by receiving a QoS CF-Poll (Contention-Free Poll) frame from the AP. The former is called an EDCA TXOP, and the latter is called a Polled TXOP. In this way, the concept of TXOP can be used to grant a certain amount of time for a STA to transmit a frame, or to forcibly limit the transmission time.

[0168] The transmission start time and maximum transmission time of TXOP are determined by the AP, which is notified to the STA by a beacon frame for EDCA TXOP and by a QoS CF-Poll frame for Polled TXOP.

[0169] NAV can be understood as a type of timer to protect the TXOP of a transmitting STA (e.g., a TXOP holder). An STA can protect the TXOP of another STA by not performing channel access while its NAV is valid. In the current wireless LAN system, the TXOP duration is set through the duration field of the MAC header. That is, the TXOP holder and the TXOP responder (e.g., the Rx STA) transmit the entire TXOP information required for transmitting and receiving frames by including it in the duration field of the frames they transmit and receive. Third-party STAs that are not the TXOP holder or the TXOP responder (e.g., third-party STAs) check the Duration field of the frames exchanged between the TXOP holder and the TXOP responder, and postpone channel use until the NAV duration by setting / updating the NAV.

[0170] Below we describe the 802.11be standard. 802.11be, also known as EHT (extremely high throughput), operates in the 2.4, 5, and 6 GHz bands and is being developed to provide speeds up to 46 Gbps, which is 4.8 times faster than WiFi 6, by introducing 320 MHz of bandwidth, 4096QAM, multiple resource units (RUs), and multi-link operation (MLO), while providing low latency and high network throughput. Specifically, 802.11be provides a wide bandwidth of 320 MHz in the 6 GHz band, and can transmit data via MU-MIMO with 16 spatial streams in both the uplink and downlink, and adopts 4096QAM to achieve high transmission efficiency. In addition, it has the characteristics of increasing spectrum efficiency by flexibly performing spectrum resource scheduling through multiple RUs, and simultaneously transmitting and receiving data in various frequency bands and channels through multi-link operation.

[0171] Below, we describe the overlapping basic service set (OBSS). Existing wireless LAN networks experience significant performance degradation, including throughput, as users increase. This is because wireless LAN systems fundamentally utilize CSMA / CA, a time-division access control scheme. When a neighboring network is detected, the system divides the frequency resources in the same band by the amount of time the neighboring network is active.

[0172] Currently, there are many cases where multiple APs are operating in a specific area, and in this case, the performance of the wireless LAN network deteriorates due to overlapping coverage between APs. This is because the APs of each BSS and the STAs connected to the APs are affected by the signals of the neighboring BSS, resulting in interference by the neighboring BSS, which in turn causes a decrease in the transmission rate due to collisions between signals transmitted at the same time. BSSs that can affect signal transmission in this way (or whose coverage overlaps) can be referred to as overlapping BSSs (OBSS). To solve this problem, interference avoidance technologies that divide the bands available to each user so that they do not overlap or perform channel switching to unused channels, as well as interference alignment technologies that reduce the impact of interference even when using the same band, are being studied.

[0173] FIG. 8 is a diagram illustrating an example of channel access to which various embodiments of the present disclosure may be applied. FIG. 8 is for explaining non-primary channel access (NPCA). In FIG. 8, a wideband channel is illustrated as being composed of a 20 MHz primary channel (primary 20 MHz channel) and multiple 20 MHz secondary channels (secondary 20 MHz channels). This is for convenience of explanation and the present disclosure is not limited thereto.

[0174] A primary channel is a common channel operated by all STAs that are members of a BSS. For example, in a 20 MHz, 40 MHz, 80 MHz, 160 MHz, or 80 + 80 MHz BSS, the primary channel may be the primary 20 MHz channel.

[0175] A secondary channel is a channel associated with a primary channel and is used to create a wider channel than the primary channel. For example, in a 40 MHz, 80 MHz, 160 MHz, or 80 + 80 MHz BSS, the secondary channel may be a secondary 20 MHz channel.

[0176] According to the current 801.11 standard, for any transmission (e.g., transmission on 20 / 40 / 80 / 160 / 320MHz channels), the primary channel (primary 20MHz channel) must be idle to allow access to wideband channels larger than 20MHz. Therefore, if the primary channel is busy, the AP / STA cannot transmit on any idle secondary channel. In other words, if the primary channel is busy, no transmission can be performed on the secondary channel even if the secondary channel is idle.

[0177] For example, referring to Fig. 8(a), even if the secondary channel is available, transmission cannot be performed if the primary channel is busy.

[0178] For example, the primary channel may be busy due to interference from a 20MHz PPDU corresponding to an overlapping BSS (OBSS), in which case transmission cannot be performed even if secondary channels of 60MHz are available.

[0179] For example, the primary channel may be busy due to interference from a 40MHz PPDU corresponding to an OBSS, in which case transmission cannot be performed even if the 40MHz secondary channels are available.

[0180] That is, according to the current 801.11 standard, when the primary channel is idle, the STA can transmit packets. That is, when the primary channel is idle, the STA can perform transmission (e.g., transmission of 80MHz PPDU) using the primary channel and the secondary channel. This applies equally to the UL (uplink) transmission of the STA as well as the DL (downlink) transmission of the AP.

[0181] Therefore, the current secondary channel access mechanism (or scheme) is inefficient for wideband channels (e.g., 160MHz channel, 320MHz channel) or large bandwidth, and a better secondary channel access mechanism (or scheme) is required to fully utilize wideband channels.

[0182] Non-primary channel access (NPCA) is being discussed as a solution to the above-mentioned problems. NPCA can be triggered based on OBSS PPDUs and / or OBSS TXOPs. According to NPCA, if the primary channel is busy and the secondary channel is available, the AP / STA can transmit on the available secondary channel.

[0183] An NPCA primary channel may be defined among the secondary channels (or within the secondary channels). The NPCA primary channel may be a channel on which channel access (e.g., EDCA) is performed while the primary channel is busy. That is, the NPCA primary channel may be a 20 MHz channel on which channel access is performed while the primary channel is busy within the secondary channels. The NPCA primary channel may be referred to as an anchor channel, but the present disclosure is not limited to this specific name.

[0184] For example, referring to FIG. 8(b), when the primary channel is busy, transmission can be performed on available secondary channels.

[0185] For example, if the primary channel is busy due to interference by a 20MHz PPDU corresponding to an OBSS, the STA can transmit packets (e.g., 60MHz PPDU) on available secondary channels while the primary channel is busy. Channel access can be performed on an anchor channel within the secondary channels, thereby allowing packets to be transmitted on the secondary channels when the anchor channel is idle. This applies equally to UL transmissions of the STA as well as DL transmissions of the AP.

[0186] For example, if the primary channel is busy due to interference by a 40MHz PPDU corresponding to an OBSS, the STA can transmit packets (e.g., 40MHz PPDU) on available secondary channels while the primary channel is busy. Channel access can be performed on an anchor channel within the secondary channels, thereby allowing packets to be transmitted on the secondary channels when the anchor channel is idle. This applies equally to UL transmissions of the STA as well as DL transmissions of the AP.

[0187] In the description of one embodiment of the present disclosure, an NPCA AP may mean an AP having the capability to perform NPCA (or an AP performing / capable of performing operations related to NPCA), and an NPCA STA may mean an STA associated with an NPCA AP having the capability to perform NPCA (or an STA performing / capable of performing operations related to NPCA). Unless specifically stated otherwise, AP, NPCA AP, STA, and NPCA STA may be used interchangeably in the present disclosure.

[0188] When the OBSS initiates the OBSS TXOP, the NPCA AP and / or NPCA STA within the BSS may set BasicNAV (Basic NAV. NAV) and perform NPCA. For example, the BasicNAV may be set for the primary channel. For example, when the OBSS identifies that the OBSS has initiated the OBSS TXOP based on the RTS-CTS exchange, the NPCA AP and / or NPCA STA within the BSS may set BasicNAV and perform NPCA. Here, whether or not to perform NPCA may be identified based on a comparison between the OBSS TXOP and a specific duration threshold. For example, when the OBSS TXOP is shorter than (or less than) the specific duration threshold, NPCA may not be performed. Conversely, NPCA may be performed if the OBSS TXOP is longer than (or greater than) a certain interval threshold. This is because, if the OBSS TXOP is relatively short, it may be more advantageous to wait until the end of the OBSS TXOP than to perform an operation based on NPCA.

[0189] Secondary channels on which NPCA will operate and anchor channels (e.g., a 20 MHz anchor channel) on which channel access (e.g., EDCA) procedures will be performed within the secondary channels may be pre-configured / pre-agreed upon between NPCA APs and / or NPCA STAs within a BSS. The secondary channels on which NPCA will operate may be named NPCHs (non-primary channels), but the present disclosure is not limited to these specific names.

[0190] The operation of NPCA AP can be as follows:

[0191] An NPCA AP may not perform NPCA in a band outside of its operating bandwidth. That is, an NPCA AP may perform NPCA within its operating bandwidth.

[0192] An NPCA AP can perform NPCA if the secondary channel is idle during the PIFS interval immediately preceding the starting point of an OBSS TXOP.

[0193] If an NPCA AP has a separate NAV timer, i.e., a separate NPCH NAV timer is configured for the anchor channel, and the NPCH NAV timer has a non-zero value, the NPCA AP may not be able to initiate a TXOP within the NPCH. If an NPCA AP has a separate NAV timer, i.e., a separate NPCH NAV timer is configured for the anchor channel, and the NPBCH NAV timer is 0, the NPCA AP may initiate a TXOP within the NPCH.

[0194] An NPCA AP can perform channel access (e.g., EDCA contention) on an anchor channel where OBSS transmissions do not overlap, and the remaining channels within the NPCH (excluding the anchor channel) can be accessed by ED (energy detection). For example, if the PIFS is idle just before the backoff counter of the anchor channel expires, the remaining channels can be accessed.

[0195] The operation of NPCA STA can be as follows.

[0196] NPCA STAs can switch their operating bandwidths to perform NPCA. Unlike NPCA APs, which do not perform NPCA outside their operating bandwidth, NPCA STAs can also switch their operating bandwidths to perform NPCA. For example, NPCA STAs can perform NPCA based on AP instructions / configurations and / or by switching to predefined / promised operating bandwidths.

[0197] The NPCA capability of an STA and / or the on / off status of the NPCA capability can be established through prior information and / or message exchange. An STA and an AP can confirm whether NPCA can be performed, i.e., NPCA capability, by exchanging Probe requests and Probe responses or Association requests and Association responses. Thereafter, an AP and STA capable of performing NPCA exchange OBSS information (e.g., MAC addresses or color information of OBSS APs and STAs) visible (detected in the vicinity) to establish a list of OBSSs that are not in a hidden relationship with each other, and can perform NPCA when transmission occurs due to the OBSS. When performing NPCA, an anchor channel for performing EDCA and an NPCH capable of transmitting data including the anchor channel can be established in advance through information exchange between the NPCA AP and the NPCA STA.

[0198] Unless specifically stated otherwise, in the description of an embodiment of the present disclosure, the word "more than" may be replaced with "more than," and the word "more than" may be replaced with "more than." Unless specifically stated otherwise, in the description of an embodiment of the present disclosure, the word "less than" may be replaced with "less than."

[0199] Various embodiments of the present disclosure may provide a method for terminating and / or stopping NPCA. If NPCA has been initiated, a method for terminating and / or stopping it may be provided. If NPCA is terminated and / or stopped, the NPCA AP and / or NPCA STA may return to the primary channel. After returning to the primary channel, the AP and / or STA may participate in contention and perform transmission based on the contention result.

[0200] According to various embodiments of the present disclosure, an NTC (NPCA termination and truncation Control) frame (hereinafter, NTC or NTC frame) may be used to terminate and / or suspend NPCA. The name is an example, and the present disclosure is not limited thereto.

[0201] Various embodiments of the present disclosure may provide rules for using NTC, methods for defining NTC, and conditions for transmitting NTC.

[0202] The various embodiments of the present disclosure described above will be described in more detail below. The following embodiments may be applied independently, or at least some of them may be applied in combination.

[0203] Hereinafter, the basic rules of NTC according to one embodiment of the present disclosure are described. This may relate to a method of notifying NTC. According to one embodiment of the present disclosure, NTC may be delivered according to implicit notification or explicit notification.

[0204] (1) Implicit notification

[0205] According to one embodiment of the present disclosure, NTC can be indicated / notified using a specific subfield of the frame control field. A specific subfield of the frame control field can be used for implicit notification without defining a separate NTC frame.

[0206] According to one embodiment of the present disclosure, NTC can be indicated using the More Data subfield of the Frame Control field. The More Data subfield of the Frame Control field can be used for implicit notification without defining a separate NTC frame.

[0207] According to one embodiment of the present disclosure, when multiple PPDUs are transmitted through NPCH, NPCA may be terminated if the More Data subfield of the frame control field of a recently received PPDU is set to 0. The NPCA AP and / or NPCA STA may set the value of the More Data subfield to 1 during NPCA operation, and if set to 0, it may indicate the termination of NPCA.

[0208] According to one embodiment of the present disclosure, when the More Data subfield of the frame control field included in the PPDU transmitted from the NPCA AP is set to 0, this may indicate that the entire NPCA has been terminated. That is, the NPCA AP and the NPCA STA associated with the NPCA AP may terminate the NPCA.

[0209] According to one embodiment of the present disclosure, when the More Data subfield of the frame control field included in a PPDU transmitted from an NPCA STA is set to 0, it may indicate that the NPCA operation of the corresponding NPCA STA has ended. That is, the NPCA STA that transmitted the PPDU may end the NPCA.

[0210] FIGS. 9A to 9G are diagrams showing an example of an implicit notification method of NTC according to one embodiment of the present disclosure.

[0211] Figure 9a illustrates the Frame Control field format in non-S1G (sub 1GHz) PPDUs when the Type subfield is not equal to 1 or the Subtype subfield is not equal to 6. The Frame Control field may include a Protocol Version subfield (2 bits, B0 to B1), a Type subfield (2 bits, B2 to B3), a Subtype subfield (4 bits, B4 to B7), a To DS (Distribution System) subfield (1 bit, B8), a From DS subfield (1 bit, B9), a More Fragments subfield (1 bit, B10), a Retry subfield (1 bit, B11), a Power Management subfield (1 bit, B12), a More Data subfield (1 bit, B13), a Protected Frame subfield (1 bit, B14), and a +HTC (high-throughput control) subfield (1 bit, B15). According to one embodiment of the present disclosure, the More Data subfield (1 bit, B13) may be used for implicit notification.

[0212] FIG. 9B illustrates the Frame Control field format in non-S1G PPDUs when the Type subfield is equal to 1 and the Subtype subfield is equal to 6. The Frame Control field may include a Protocol Version subfield (2 bits, B0 to B1), a Type subfield (2 bits, B2 to B3), a Subtype subfield (4 bits, B4 to B7), a Control Frame Extension subfield (4 bits, B8 to B11), a Power Management subfield (1 bit, B12), a More Data subfield (1 bit, B13), a Protected Frame subfield (1 bit, B14), and a +HTC subfield (1 bit, B15). According to one embodiment of the present disclosure, the More Data subfield (1 bit, B13) may be used for implicit notification.

[0213] FIG. 9c illustrates the Frame Control field format in S1G PPDUs when the Type subfield is equal to 0 or 2. The Frame Control field may include a Protocol Version subfield (2 bits, B0 to B1), a Type subfield (2 bits, B2 to B3), a Subtype subfield (4 bits, B4 to B7), a To DS subfield (1 bit, B8), a From DS subfield (1 bit, B9), a More Fragments subfield (1 bit, B10), a Retry subfield (1 bit, B11), a Power Management subfield (1 bit, B12), a More Data subfield (1 bit, B13), a Protected Frame subfield (1 bit, B14), and a +HTC subfield (1 bit, B15). According to one embodiment of the present disclosure, the More Data subfield (1 bit, B13) can be used for implicit notification.

[0214] FIG. 9d illustrates subfield values ​​within the Frame Control field of a control frame carried in a non-S1G PPDU. The Frame Control field may include a Protocol Version subfield (2 bits, B0 to B1), a Type (Control) subfield (2 bits, B2 to B3), a Subtype subfield (4 bits, B4 to B7), a To DS (0) subfield (1 bit, B8), a From DS (0) subfield (1 bit, B9), a More Frag (Fragment) (0) subfield (1 bit, B10), a Retry (0) subfield (1 bit, B11), a Power Management subfield (1 bit, B12), a More Data subfield (1 bit, B13), a Protected Frame (0) subfield (1 bit, B14), and a +HTC (0) subfield (1 bit, B15). According to one embodiment of the present disclosure, the More Data subfield (1 bit, B13) can be used for implicit notification.

[0215] FIG. 9e illustrates the subfield values ​​included in the Frame Control field format in Control frames carried in an S1G PPDU when the Subtype subfield is not equal to 3 and not equal to 10. The Frame Control field may include a Protocol Version subfield (2 bits, B0 to B1), a Type subfield (2 bits, B2 to B3), a Subtype subfield (4 bits, B4 to B7), a Bandwidth Indication subfield (3 bits, B8 to B10), a Dynamic Indication subfield (1 bit, B11), a Power Management subfield (1 bit, B12), a More Data subfield (1 bit, B13), a Protected Frame subfield (1 bit, B14), and a +HTC subfield (1 bit, B15). According to one embodiment of the present disclosure, the More Data subfield (1 bit, B13) can be used for implicit notification.

[0216] FIGS. 9A to 9E illustrate examples of frame control fields to which various embodiments of the present disclosure may be applied, and are not limited to the frame control fields illustrated in FIGS. 9A to 9E . Any More Data subfield included in any frame control field may be used for implicit notification according to an embodiment of the present disclosure. Furthermore, although an embodiment of the present disclosure primarily describes the More Data subfield as an example, other subfields may be used for implicit notification according to an embodiment of the present disclosure.

[0217] For example, since the TXOP set during NPCA operation is trigger-based and the AP operates to preempt the TXOP, the More TF subfield can be used for implicit notification. The Common Info field in the Trigger frame transmitted by the NPCA AP can include the More TF subfield. The More TF subfield can be a 1-bit indicator. For example, if the value of More TF is 1, it can mean that an additional TF is scheduled. Conversely, if it is 0, it can mean that an additional TF is not scheduled. If the NPCA operation is continuous / continuous, the value of More TF can be set to 1. If the value of More TF is set to 0, it indicates that an additional TF is not scheduled, which can implicitly indicate that the NPCA operation has ended.

[0218] That is, according to one embodiment of the present disclosure, when the More TF subfield of the Common Info field included in the Trigger frame transmitted from the NPCA AP within the NPC TXOP during the NPCA operation is set to 0, it may indicate that the NPCA operation of the NPCA AP and NPCA STAs has been terminated. That is, all NPCA STAs that have received a TF with the More TF subfield as 0 may terminate the NPCA. Accordingly, when the NPCA AP continues / continues an additional NPCA operation, that is, transmits an additional TF within the NPC TXOP or attempts to additionally set an NPC TXOP after the termination of the NPC TXOP, the More TF subfields within all TFs transmitted immediately before may be set to 1.

[0219] Figure 9f illustrates an example of a HE (High Efficiency) variant Common Info field format. The HE variant Common Info field contains the Trigger Type subfield (4 bits, B0 to B3), the UL Length subfield (12 bits, B4 to B15), the More TF subfield (1 bit, B16), the CS (carrier sense) Required subfield (1 bit, B17), the UL BW (bandwidth) subfield (2 bits, B18 to B19), the GI (guard interval) And HE-LTF (high efficiency long training field) Type / Triggered TXOP Sharing Mode subfield (2 bits, B20 to B21), the MU-MIMO (multi user-multi input multi output) HE-LTF Mode subfield (1 bit, B22), the Number Of HE-LTF Symbols And Midamble Periodicity subfield (3 bits, B23 to B25), the UL STBC (space-time block coding) subfield (1 bit, B26), and the LDPC (low-density parity check) Extra Symbol Segment subfield (1 bit, B27), AP Tx Power subfield (6 bits, B28 to B33), Pre-FEC (forward error correction) Padding Factor subfield (2 bits, B34 to B35), PE (packet extension) Disambiguity subfield (1 bit, B36), UL Spatial Reuse subfield (16 bits, B37 to B52), Doppler subfield (1 bit, B53), UL HE-SIG-A2 (high efficiency signal A2) Reserved subfield (9 bits,B54 to B62), a Reserved subfield (1 bit, B63) and a Trigger Dependent Common Info subfield (variable). According to one embodiment of the present disclosure, the More TF subfield (1 bit, B16) may be used for implicit notification.

[0220] Figure 9g illustrates the EHT variant Common Info field format. The EHT variant Common Info field includes a Trigger Type subfield (4 bits, B0 to B3), a UL Length subfield (12 bits, B4 to B15), a More TF subfield (1 bit, B16), a CS Required subfield (1 bit, B17), a UL BW (bandwidth) subfield (2 bits, B18 to B19), a GI And HE-LTF Type / Triggered TXOP Sharing Mode subfield (2 bits, B20 to B21), a Reserved subfield (1 bit, B22), a Number Of HE / EHT-LTF Symbols subfield (3 bits, B23 to B25), a Reserved subfield (1 bit, B26), an LDPC Extra Symbol Segment subfield (1 bit, B27), an AP Tx Power subfield (6 bits, B28 to B33), a Pre-FEC Padding Factor subfield (2 bits, B34 to B35), and a PE It may include a Disambiguity subfield (1 bit, B36), a UL Spatial Reuse subfield (16 bits, B37 to B52), a Reserved subfield (1 bit, B53), a HE / EHT P160 subfield (1 bit, B54), a Special User Info Field Flag subfield (1 bit, B55), an EHT Reserved subfield (7 bits, B56 to B62), a Reserved subfield (1 bit, B63), and a Trigger Dependent Common Info subfield (variable). According to one embodiment of the present disclosure, the More TF subfield (1 bit, B16) may be used for implicit notification.

[0221] FIGS. 9F to 9G illustrate examples of frames to which various embodiments of the present disclosure may be applied, and are not limited to the frames illustrated in FIGS. 9F to 9G . A More TF subfield included in any frame control field may be used for implicit notification according to an embodiment of the present disclosure.

[0222] (2) Explicit notification according to NTC transmission in NPCH

[0223] According to one embodiment of the present disclosure, the NTC may be explicitly notified / indicated. The NTC may be transmitted on the NPCH.

[0224] According to one embodiment of the present disclosure, upon transmitting or receiving an NTC, the NPCA AP and / or the NPCA STA may terminate the NPCA. Upon transmitting or receiving an NTC, the NPCA AP and / or the NPCA STA may immediately terminate the NPCA. An NPCA interval may include one or more TXOPs (NPC (non-primary channel) TXOPs), and the last TXOP may include an NTC for indicating the termination of the NPCA. The last TXOP of the NPCA may include an NTC transmission that does not solicit any response, transmitted by the NPCA AP.

[0225] According to one embodiment of the present disclosure, an NPCA AP and / or an NPCA STA may return to the primary channel before the expiration of the BasicNAV. The timing of transmitting the NTC may be based on a channel switching delay. The NTC may be transmitted earlier than the end of the OBSS TXOP, taking into account the channel switching delay, so that both the NPCA AP and the NPCA STA are locked to the primary channel before the BasicNAV of the primary channel becomes 0. This is because a synchronization problem may occur when the AP and / or the STA returns to the primary channel after the expiration of the BasicNAV. For example, if an STA returns to the primary channel after the BasicNAV, a problem may occur when the STA attempts to participate in EDCA contention for transmission, which may be caused by another STA having already initiated the EDCA contention.

[0226] For example, if an OBSS TXOP ends earlier than it was initially announced, the NPCA AP and NPCA STAs that are transmitting and receiving on the NPCH may not be able to recognize the early termination of the OBSS TXOP and thus may not be able to participate in contention on the primary channel. In this case, if an STA that is associated with the NPCA AP and has not performed NPCA attempts an uplink transmission, the NPCA AP will not be able to receive it. Furthermore, even if the OBSS acquires the TXOP on the primary channel again, the NPCA AP and NPCA STAs may not be able to recognize the new transmission and thus may not be able to accurately determine when the OBSS transmission ends, making it difficult to determine whether to perform / continue NPCA.

[0227] According to one embodiment of the present disclosure, the NTC may be transmitted earlier than the end of the OBSS TXOP by taking into account the channel switching delay, so that the above-described problem may not occur.

[0228] According to one embodiment of the present disclosure, when an NPCA truncation is confirmed, an NPCA truncation timer may be run for a predetermined time. The name of the timer is an example, and the present disclosure is not limited thereto. When the NPCA truncation timer expires, the NPCA may be terminated even if the NTC was not successfully transmitted. While the NPCA truncation timer is running, an NTC transmission may be attempted, and even if the NTC was not successfully transmitted, the AP may return to the primary channel when the NPCA truncation timer expires. This may be because, in particular, the AP may consider that an STA that cannot perform NPCA operation may be operating on a conventional channel (primary channel), and thus the AP should return to the primary channel for the STA. An example of a case where the NTC is not successfully transmitted on the NPCH may be a case where EDCA contention is performed for NTC transmission on the NPCH, but the channel is not occupied due to the EDCA contention.

[0229] (3) Explicit notification of NTC transmission on primary channel

[0230] According to one embodiment of the present disclosure, the NTC can be explicitly notified / indicated. The NTC can be transmitted on the primary channel. This can be applied in combination with and / or separately from the case of explicit notification according to NTC transmission on the NPCH according to one embodiment of the present disclosure described above. For example, if the NPCA interruption timer described above expires and the NTC cannot be transmitted on the NPCH and the AP returns to the primary channel, the AP can transmit the NTC on the primary channel (or the entire bandwidth including the primary channel (entire channel)).

[0231] According to one embodiment of the present disclosure, the NTC may be in the form of non-HT or non-HT duplicate. The NTC being in the form of non-HT or non-HT duplicate may enable the NPCA AP to transmit the NTC via the NPCH within the NPCA TXOP and / or enable the NPCA AP to transmit the NTC in the full bandwidth after performing EDCA contention on the primary channel after NPCA termination.

[0232] According to one embodiment of the present disclosure, if the NPCA AP confirms the suspension of NPCA or fails to transmit NTC on NPCH, the NPCA AP may terminate NPCA and transmit NTC on the entire band including NPCH after EDCA contention on the primary channel. An example of a case where NTC transmission on NPCH fails may be a case where EDCA contention for NTC transmission on NPCH is performed but the channel is not occupied due to EDCA contention.

[0233] Hereinafter, a method for defining an NTC format according to an embodiment of the present disclosure will be described. The method for defining an NTC format according to an embodiment of the present disclosure may include a method of introducing a new control frame design or a method of (re)using a specific control frame (e.g., CF-End or CTS-to-Self).

[0234] (1) New control frame design

[0235] According to one embodiment of the present disclosure, the Type field (subfield) and / or the Subtype field (subfield) in the Frame Control field of the frame (control frame) may be used to indicate the NTC format. If the Type subfield in the Frame Control field of the frame (control frame) is 01 and the Subtype subfield is 0001, the frame may be an NTC frame. If the frame is an NTC frame, the value of the Duration field of the frame may be 0. In addition, if the frame is an NTC frame, one of the TA (transmitter address or transmitting station address) field or the RA field (receiver address or receiving station address) of the frame may correspond to the BSSID or MAC address of the NPCA AP.

[0236] According to one embodiment of the present disclosure, the Type field (subfield) and / or the Subtype field (subfield) and / or the Control Frame Extension field (subfield) in the Frame Control field of a frame (control frame) may be used to indicate an NTC format. If the Type subfield of the Frame Control field of the frame is 01, the Subtype subfield is 0110, and the Control Frame Extension subfield is one of values ​​from 1011 to 1111, the frame may be an NTC frame. If the frame is an NTC frame, the value of the Duration field of the frame may be 0. In addition, if the frame is an NTC frame, one of the TA field or the RA field of the frame may correspond to the BSSID or (MAC) address of the NPCA AP.

[0237] (2) How to (re)use specific control frames (e.g., CF-End or CTS-to-Self).

[0238] According to one embodiment of the present disclosure, a specific control frame (e.g., CF-End or CTS-to-Self) may be used to indicate the NTC format.

[0239] FIG. 10 is a diagram showing an example of an NTC format using CF-End according to one embodiment of the present disclosure.

[0240] FIG. 11 is a diagram illustrating an example of an NTC format using CTS-to-Self according to one embodiment of the present disclosure.

[0241] Referring to FIGS. 10 and 11, according to one embodiment of the present disclosure, an NPCA STA can immediately terminate NPCA by referring to the BSSID (TA) field of CF-End or the RA field of CTS-to-Self if the address indicates an NPCA AP.

[0242] According to one embodiment of the present disclosure, the NPCA AP may notify the NTC by assigning the address (e.g., MAC address) of the NPCA AP to the BSSID (TA) field of the CF-End. The NPCA STA may immediately terminate the NPCA if the BSSID (TA) field of the CF-End indicates the NPCA AP.

[0243] According to one embodiment of the present disclosure, an NPCA AP may notify NTC by assigning the address of the NPCA AP to the RA field of the CTS-to-Self. An NPCA STA may immediately terminate NPCA if the RA field of the CTS-to-Self indicates an NPCA AP.

[0244] According to one embodiment of the present disclosure, when an NPCA AP transmits NTC using CF-End or CTS-to-Self, one reserved bit of the frame control field of CF-End or CTS-to-Self may be used to indicate that CF-End or CTS-to-Self is used for NTC. For example, referring to FIGS. 9A to 9E , this may be indicated using B12 of the frame control field, i.e., the Power Management subfield.

[0245] According to one embodiment of the present disclosure, when an NPCA AP transmits an NTC, the NPCA AP may use one reserved bit of the frame control field to determine whether the NTC is for the NPCH only or for the entire bandwidth including the primary channel. Referring to FIGS. 9A to 9E , B12 of the frame control field, i.e., the Power Management subfield (Power Management bit), may be used to indicate whether the NTC is for the NPCH only or for the entire bandwidth including the primary channel. When an NPCA AP transmits an NTC, one bit of the frame control field may be used to indicate whether the NTC is for the NPCH or for the entire bandwidth including the primary channel. For example, when one bit is set to 1 (or 0), it may indicate that the NTC is for the NPCH, and when one bit is set to 0 (or 1), it may indicate that the NTC is for the entire bandwidth including the primary channel. A 1 bit indicating that the NTC is for the NPCH may correspond to an explicit notification that the NTC is for an NTC transmission on the NPCH according to an embodiment of the present disclosure, and a 1 bit indicating that the NTC is for the entire bandwidth including the primary channel may correspond to an explicit notification that the NTC is for an NTC transmission on the primary channel according to an embodiment of the present disclosure. Alternatively, a 1 bit indicating that the NTC is for the NPCH may correspond to a CF-End or CTS-to-Self including that 1 bit was used for an NTC, and a 1 bit indicating that the NTC is for the entire bandwidth including the primary channel may correspond to a CF-End or CTS-to-Self including that 1 bit was not used for an NTC.

[0246] According to one embodiment of the present disclosure, CF-End and / or CTS-to-Self used for NTC may not change existing NAV settings. An STA that has previously received CF-End on a primary channel (or a bandwidth including the primary channel) must reset (suspend) its NAV settings and update its NAV with the Duration field value of the corresponding frame when receiving CTS-to-Self. Applying the same, if a specific STA sets BasicNAV on the primary channel and receives CF-End during NPCA operation, it resets the BasicNAV. However, according to one embodiment of the present disclosure, since CF-End and / or CTS-to-Self used for NTC do not change existing NAV settings, the STA may identify the end of NPCA from CF-End and / or CTS-to-Self used for NTC and not reset / update BasicNAV. It can be distinguished from the above 1 bit whether CF-End and / or CTS-to-Self are used for the termination of NPC TXOP or for the conventional purpose (NAV setting reset / update).

[0247] For example, CF-End / CTS-to-Self received on NPCH may not change existing NAV settings.

[0248] According to one embodiment of the present disclosure, the Duration field of CF-End and / or CTS-to-Self for termination of NPCA may be set to 0.

[0249] According to one embodiment of the present disclosure, the Duration field of CTS-to-Self for terminating NPCA is basically set to 0, but if the NPCA AP starts a TXOP with CTS-to-Self on the primary channel, the Duration field of CTS-to-Self may have a non-zero value. In this case, the NPCA STA running NPCA on the NPCH may update the NAV of the primary channel and immediately terminate NPCA. That is, if CTS-to-Self is used both for the purpose of terminating NPCA and for the purpose of ICF (initial control frame), the Duration field of CTS-to-Self may be set to a non-zero value. If CTS-to-Self is used for the purpose of ICF on the primary channel, the NPCA STA that receives it during NPCA operation may immediately terminate NPCA.

[0250] Hereinafter, the transmission conditions of NTC and / or NPCA truncation conditions according to one embodiment of the present disclosure will be described.

[0251] In the following description, it is assumed that the NPCA AP or NPCA STA performs the EDCA procedure on the anchor channel while performing NPCA in the NPCA interval (T_NPCA). In addition, in the following description, it is assumed that when the NPCA AP or NPCA STA terminates or aborts the NPCA operation, the NPCA AP or NPCA STA reverts to the primary channel while complying with the existing channel access (e.g., the EDCA procedure and BasicNAV rules). This is for convenience of description and the present disclosure is not limited thereto.

[0252] NPCA termination conditions according to one embodiment of the present disclosure may be as follows.

[0253] (1) According to one embodiment of the present disclosure, when an OBSS PPDU is received on the NPCH or an OBSS TXOP is detected on the NPCH, NPCA may be suspended. When an OBSS PPDU is received on the NPCH or an OBSS TXOP is detected on the NPCH, and the detected OBSS PPDU duration or OBSS TXOP duration is long, making it difficult for the NPCA AP or NPCA STA to acquire TXOP on the NPCH channel during a given T_NPCA, NPCA may be suspended. When an OBSS PPDU is received on the NPCH or an OBSS TXOP is detected on the NPCH, and the length of the detected OBSS PPDU duration or OBSS TXOP duration makes it difficult for the NPCA AP or NPCA STA to acquire TXOP on the NPCH channel during a given T_NPCA, NPCA may be suspended.

[0254] - For example, if the OBSS PPDU interval or OBSS TXOP interval of NPCH exceeds the remaining T_NPCA, NPCA may be interrupted.

[0255] - For example, if the remaining time before expiration of T_NPCA after the end of the OBSS PPDU period or OBSS TXOP period on NPCH is expected to be less than the TXOP limit (TXOPlimit) established for transmission of NPCA AP or NPCA STA, NPCA may be aborted. The NPC TXOP established within the NPC TXOP shall be greater than or equal to the predefined / configured minimum reference time, and if the remaining time before expiration of T_NPCA after the end of the OBSS PPDU period or OBSS TXOP period on NPCH is (or is expected to be) less than the minimum reference time for NPC TXOP, NPCA may be aborted.

[0256] - For example, if a separate NPC NAV timer (NPCNAVTimer) is used on the anchor channel, NPCA termination may occur even if the NPCNAVTimer value satisfies the requirements described above. That is, if the value of NPCNAVTimer exceeds the remaining T_NPCA, NPCA may be aborted. Alternatively, if after the termination of NPCNAVTimer, the remaining time before expiration of T_NPCA is less than (or expected to be less than) the minimum reference time for NPC TXOP, NPCA may be aborted.

[0257] - Conversely, if the OBSS PPDU interval or OBSS TXOP interval of NPCH (or the value of NPCNAVTimer) does not exceed (is less than) the remaining T_NPCA, and if the remaining time before the expiration of T_NPCA after the expiration of NPCNAVTimer is not expected to be less than (is expected to be greater than) TXOPlimit, NPCA may not be interrupted.

[0258] (2) According to one embodiment of the present disclosure, if a management frame is found on the anchor channel, NPCA may be stopped. For example, if a management frame such as a beacon, a probe response, and / or a (re)association response is found on the anchor channel, NPCA may be stopped. Since the management frame is transmitted on the primary channel (20 MHz), NPCA may be stopped if a management frame for another AP / STA (or of the OBSS) exists on the anchor channel.

[0259] (3) According to one embodiment of the present disclosure, if there is no active NPCA STA on the anchor channel (or it is expected that there will be no active NPCA STA), the NPCA AP may suspend NPCA. For example, if there is no NPCA STA responding to a multi user-request to send (MU-RTS), a buffer status report poll (BSRP), or a basic trigger frame sent by the NPCA AP, the NPCA AP may suspend NPCA.

[0260] (4) According to one embodiment of the present disclosure, if the NPCA AP and / or the NPCA STA does not have a BU (buffered unit) to be transmitted or received on the NPCH, the NPCA AP and / or the NPCA STA may stop NPCA.

[0261] - For example, if there is no DL (downlink) BU of NPCA AP, NPCA may be interrupted.

[0262] - For example, if there is no DL TIM (traffic indication map) allocation for an NPCA STA and there is no UL (uplink) BU for the NPCA STA, the NPCA may be interrupted.

[0263] - For example, if an NPCA STA does not receive any kind of frame from an NPCA AP for a certain time interval (NPCASchedTimer), NPCA may be interrupted.

[0264] (5) According to one embodiment of the present disclosure, when the OBSS TXOP of the primary channel is interrupted, NPCA may be interrupted. For example, when an interruption of the OBSS TXOP on the primary channel is observed due to reception of a CF-End, etc., the NPCA AP and / or NPCA STA may interrupt NPCA.

[0265] Below, examples of operations according to various embodiments of the present disclosure are described with reference to the drawings. The following description may be applied to the various embodiments of the present disclosure described above. The following examples are provided to facilitate understanding of the various embodiments of the present disclosure, and the present disclosure is not limited to the following examples.

[0266] Hereinafter, an 80MHz bandwidth (P80) including (or configured as) a primary channel and an 80MHz bandwidth (S80, NPCH) including (or configured as) a secondary channel are configured in a 160MHz bandwidth. This is an example and the present disclosure is not limited thereto. Hereinafter, an NPCA AP is illustrated as being capable of operating in a 160MHz bandwidth and an NPCA STA is illustrated as being capable of operating in 80MHz or 160MHz, but the present disclosure is not limited thereto. In the following, unless otherwise stated, in examples where an NTC is transmitted and received, it is assumed that the NTC is successfully transmitted and received.

[0267] FIG. 12 is a diagram illustrating an example of an operation related to an NPC TXOP within a period for an NPCA operation according to an embodiment of the present disclosure. FIG. 12 illustrates an example of NPC TXOPs within the period of an NPCA operation (NPCA TXOPs). FIG. 12 illustrates an example of an NPCA AP explicitly terminating NPCA by sending an NTC to NPCA STAs (Explicit termination of NPCA for NPCA AP to send NTC to NPCA STAs).

[0268] Referring to FIG. 12, in an 80 MHz bandwidth (P80), OBSS ICF, OBSS ICR, multiple OBSS PPDUs, and multiple OBSS BA (block ACK (acknowledgement)) can be transmitted.

[0269] An NPCA AP can detect an OBSS ICF-ICR exchange on the primary channel. This may be the case when an OBSS TXOP is detected on the primary channel. NPCA can be initiated by the detection of an OBSS TXOP on the primary channel. An NPCA AP can configure BasicNAV and T_NPCA. T_NPCA can be configured after receiving an OBSS ICR or after receiving an OBSS PPDU.

[0270] An NPCA STA can detect an OBSS ICF-ICR exchange on the primary channel. This may be the case when an OBSS TXOP is detected on the primary channel. NPCA can be initiated by the detection of an OBSS TXOP on the primary channel. An NPCA STA can set BasicNAV and T_NPCA. T_NPCA can be set after receiving an OBSS ICR or after receiving an OBSS PPDU.

[0271] An NPCA AP can acquire NPC TXOP#1 through EDCA contention on the anchor channel within the NPCH. Multiple data can be exchanged between the NPCA AP and NPCA STA within NPC TXOP#1. For example, TF, response, NPCA PPDU, and BA can be exchanged.

[0272] After the termination of NPC TXOP#1, the NPCA AP can acquire NPC TXOP#2 through EDCA contention on the anchor channel in the NPCH. Multiple data can be exchanged between the NPCA AP and the NPCA STA in NPC TXOP#2. For example, TF, NPCA TB (trigger-based) PPDU, BA, etc. can be exchanged. For example, TF can contain resource allocation information for NPCA TB PPDU, and transmission of NPCA TB PPDU can be based on it.

[0273] An NPCA AP can transmit an NTC in NPC TXOP#N. An NPCA AP can transmit an NTC at the end of NPC TXOP#N. NPC TXOP#N can be the last TXOP of an NPC operation. If there is only one TXOP during an NPCA, the NPCA AP can transmit an NTC at the end of the TXOP. An NPCA AP and an NPCA STA can terminate T_NPCA. The termination point of T_NPCA can be the termination point of NPC TXOP#N and / or the termination point of N_TPCA initially established by OBSS TXOP detection and / or the NTC transmission / reception point. An NPCA STA can terminate T_NPCA based on the received NTC. An NPCA AP and an NPCA STA can return to the primary channel.

[0274] The NPCA AP can return to the primary channel and participate in the contention after BasicNAV ends, and can perform transmission (e.g., transmission of DL MU PPDU) based on the contention result. Here, transmission of DL MU PPDU can be performed through the entire bandwidth (P80 and S80).

[0275] FIG. 13 is a diagram illustrating an example of an operation related to an NPC TXOP within a period for an NPCA operation according to an embodiment of the present disclosure. FIG. 13 illustrates an example of NPC TXOPs within the period of an NPCA operation. FIG. 13 illustrates an example of a case where an OBSS TXOP is detected in an NPCH.

[0276] Referring to FIG. 13, OBSS ICF, OBSS ICR, multiple OBSS PPDUs, and multiple OBSS BAs can be transmitted in an 80 MHz bandwidth (P80).

[0277] An NPCA AP can detect an OBSS ICF-ICR exchange on the primary channel. This may be the case when an OBSS TXOP is detected on the primary channel. NPCA can be initiated by the detection of an OBSS TXOP on the primary channel. An NPCA AP can configure BasicNAV and T_NPCA. T_NPCA can be configured after receiving an OBSS ICR or after receiving an OBSS PPDU.

[0278] An NPCA STA can detect an OBSS ICF-ICR exchange on the primary channel. This may be the case when an OBSS TXOP is detected on the primary channel. NPCA can be initiated by the detection of an OBSS TXOP on the primary channel. An NPCA STA can set BasicNAV and T_NPCA. T_NPCA can be set after receiving an OBSS ICR or after receiving an OBSS PPDU.

[0279] An NPCA AP can acquire NPC TXOP#1 through EDCA contention on the anchor channel within the NPCH. Multiple data can be exchanged between the NPCA AP and NPCA STA within NPC TXOP#1. For example, TF, response, NPCA PPDU, and BA can be exchanged.

[0280] After the termination of NPC TXOP#1, the NPCA AP can acquire NPC TXOP#2 through EDCA contention on the anchor channel in the NPCH. Multiple data can be exchanged between the NPCA AP and the NPCA STA in NPC TXOP#2. For example, TF, NPCA TB (trigger-based) PPDU, BA, etc. can be exchanged. For example, TF can contain resource allocation information for NPCA TB PPDU, and transmission of NPCA TB PPDU can be based on it.

[0281] After the termination of NPC TXOP#2, an OBSS TXOP may be detected on the NPCH. If the detected OBSS TXOP period is long and it becomes difficult for the NPCA AP or NPCA STA to acquire the TXOP on the NPCH channel during the given T_NPCA, the NPCA may be aborted. The T_NPCA may be aborted before the initially configured T_NPCA termination time due to the detection of an OBSS TXOP. In this case, the NTC may not be allowed to be transmitted within the T_NPCA. In this case, the NPCA AP may explicitly transmit the NTC including the NPCH on the primary channel after the termination of the NPCA. Or, in this case, the NPCA AP may not explicitly transmit the NTC. In this case, the NPCA STA may abort T_NPCA upon detection of OBSS TXOP / terminate NPCA upon termination of the initialized T_NPCA even if OBSS TXOP is not detected. The NPCA AP and NPCA STA may revert to the primary channel.

[0282] The NPCA AP can return to the primary channel and participate in the competition after BasicNAV ends, and can perform transmission (e.g., transmission of DL MU PPDU) based on the competition result. Here, since OBSS TXOP has bandwidth (S80) when transmitting DL MU PPDU, DL MU PPUU can be performed through bandwidth (P80).

[0283] FIG. 14 is a diagram illustrating an example of an operation related to an NPC TXOP within a period for an NPCA operation according to an embodiment of the present disclosure. FIG. 14 illustrates an example of NPC TXOPs within the period of an NPCA operation. FIG. 14 illustrates an example of a case where the remaining T_NPCA is shorter than the TXOPlimit established on the NPCH.

[0284] Referring to FIG. 14, OBSS ICF, OBSS ICR, multiple OBSS PPDUs, and multiple OBSS BAs can be transmitted in an 80 MHz bandwidth (P80).

[0285] An NPCA AP can detect an OBSS ICF-ICR exchange on the primary channel. This may be the case when an OBSS TXOP is detected on the primary channel. NPCA can be initiated by the detection of an OBSS TXOP on the primary channel. An NPCA AP can configure BasicNAV and T_NPCA. T_NPCA can be configured after receiving an OBSS ICR or after receiving an OBSS PPDU.

[0286] An NPCA STA can detect an OBSS ICF-ICR exchange on the primary channel. This may be the case when an OBSS TXOP is detected on the primary channel. NPCA can be initiated by the detection of an OBSS TXOP on the primary channel. An NPCA STA can set BasicNAV and T_NPCA. T_NPCA can be set after receiving an OBSS ICR or after receiving an OBSS PPDU.

[0287] An NPCA AP can acquire NPC TXOP#1 through EDCA contention on the anchor channel within the NPCH. Multiple data can be exchanged between the NPCA AP and NPCA STA within NPC TXOP#1. For example, TF, response, NPCA PPDU, and BA can be exchanged.

[0288] After the termination of NPC TXOP#1, an OBSS TXOP can be detected on the NPCH. Accordingly, if the remaining time of T_NPCA (based on the initially set T_NPCA by OBSS TXOP detection) is shorter than TXOPlimit, T_NPCA can be terminated before the end time of the initially set N_TPCA. The NPCA AP can transmit an NTC according to EDCA contention after the expiration of the OBSS TXOP. The NPCA AP and NPCA STA can terminate T_NPCA. The end time of T_NPCA can be the time of transmitting or receiving an NTC. The NPCA STA can terminate T_NPCA based on the received NTC. The NPCA AP and NPCA STA can return to the primary channel.

[0289] The NPCA AP can return to the primary channel and participate in the contention after BasicNAV ends, and can perform transmission (e.g., transmission of DL MU PPDU) based on the contention result. Here, transmission of DL MU PPDU can be performed through the entire bandwidth (P80 and S80).

[0290] Meanwhile, if there is no UL BU to be transmitted by the NPCA STA and no scheduled DL BU, NPCA may not be performed.

[0291] FIG. 15 is a diagram illustrating an example of an operation related to an NPC TXOP within a period for an NPCA operation according to an embodiment of the present disclosure. FIG. 15 illustrates an example of NPC TXOPs within the period of an NPCA operation. FIG. 15 illustrates an example of a case where a management frame from an OBSS (e.g., a beacon) is received in an NPCH.

[0292] Referring to FIG. 15, OBSS ICF, OBSS ICR, multiple OBSS PPDUs, and multiple OBSS BAs can be transmitted in an 80 MHz bandwidth (P80).

[0293] An NPCA AP can detect an OBSS ICF-ICR exchange on the primary channel. This may be the case when an OBSS TXOP is detected on the primary channel. NPCA can be initiated by the detection of an OBSS TXOP on the primary channel. An NPCA AP can configure BasicNAV and T_NPCA. T_NPCA can be configured after receiving an OBSS ICR or after receiving an OBSS PPDU.

[0294] An NPCA STA can detect an OBSS ICF-ICR exchange on the primary channel. This may be the case when an OBSS TXOP is detected on the primary channel. NPCA can be initiated by the detection of an OBSS TXOP on the primary channel. An NPCA STA can set BasicNAV and T_NPCA. T_NPCA can be set after receiving an OBSS ICR or after receiving an OBSS PPDU.

[0295] An NPCA AP can acquire NPC TXOP#1 through EDCA contention on the anchor channel within the NPCH. Multiple data can be exchanged between the NPCA AP and NPCA STA within NPC TXOP#1. For example, TF, response, NPCA PPDU, and BA can be exchanged.

[0296] After the end of NPC TXOP#1, a beacon can be received on NPCH. If an OBSS beacon is received on the anchor channel, NPCA can be stopped after transmitting NTC. That is, T_NPCA can be stopped before the end time of the initially configured N_TPCA. The NPCA AP can transmit NTC according to EDCA contention after receiving the beacon frame. The NPCA AP and NPCA STA can terminate T_NPCA. The end time of T_NPCA of the NPCA AP can be the time of transmitting the NTC. The NPCA STA can terminate T_NPCA based on the detection of the beacon frame or the received NTC. When based on the detection of a beacon frame, the end point of T_NPCA of an NPCA STA can be the detection point of a beacon frame, and when based on the received NTC, the end point of T_NPCA of an NPCA STA can be the reception point of an NTC. The NPCA AP and NPCA STA can return to the primary channel.

[0297] The NPCA AP can return to the primary channel and participate in the contention after BasicNAV ends, and can perform transmission (e.g., transmission of DL MU PPDU) based on the contention result. Here, transmission of DL MU PPDU can be performed through the entire bandwidth (P80 and S80).

[0298] FIG. 16 is a diagram illustrating an example of an operation related to an NPC TXOP within a period for an NPCA operation according to an embodiment of the present disclosure. FIG. 16 illustrates an example of NPC TXOPs within the duration of an NPCA operation. FIG. 16 illustrates an example of a case where there is no response after sending a Trigger frame at an NPCA AP.

[0299] Referring to FIG. 16, OBSS ICF, OBSS ICR, multiple OBSS PPDUs, and multiple OBSS BAs can be transmitted in an 80 MHz bandwidth (P80).

[0300] An NPCA AP can detect an OBSS ICF-ICR exchange on the primary channel. This may be the case when an OBSS TXOP is detected on the primary channel. NPCA can be initiated by the detection of an OBSS TXOP on the primary channel. An NPCA AP can configure BasicNAV and T_NPCA. T_NPCA can be configured after receiving an OBSS ICR or after receiving an OBSS PPDU.

[0301] An NPCA STA may not perform NPCA if there are no UL BUs to be transmitted and no DL BUs scheduled.

[0302] An NPCA AP can transmit a trigger frame. If there is no response from an NPCA STA within PIFS after transmitting the trigger frame, the NPCA AP can transmit an NTC and abort the NPCA. That is, T_NPCA can be aborted before the end time of the initially configured N_TPCA. The end time of the T_NPCA of the NPCA AP can be the time of transmitting the NTC. If the NPCA TXOP is not successfully initiated, the NPCA AP may need to invoke the EDCA procedure on the anchor channel to transmit the NTC. That is, the NPCA AP can transmit the NTC through the EDCA procedure. Otherwise (i.e., if the NPCA TXOP is initiated), the NTC can be transmitted immediately. That is, if there is no response from an NPCA STA within PIFS after transmitting the trigger frame when the NPCA TXOP is initiated, the NTC can be transmitted immediately.

[0303] The NPCA AP can return to the primary channel and participate in the contention after BasicNAV ends, and can perform transmission (e.g., transmission of DL MU PPDU) based on the contention result. Here, transmission of DL MU PPDU can be performed through the entire bandwidth (P80 and S80).

[0304] FIG. 17 is a diagram illustrating an example of an operation related to an NPC TXOP within a period for an NPCA operation according to an embodiment of the present disclosure. FIG. 17 illustrates an example of NPC TXOPs within the period of an NPCA operation. FIG. 17 illustrates an example of a case where an NPCA STA does not receive any kind of frame from an NPCA AP for a specific time period (NPCASchedTimer).

[0305] Referring to FIG. 17, in an 80 MHz bandwidth (P80), OBSS ICF, OBSS ICR, multiple OBSS PPDUs, and multiple OBSS BAs can be transmitted.

[0306] An NPCA AP may not perform NPCA if there are no DL BUs to transmit and no UL BUs with DL BUs scheduled.

[0307] An NPCA STA can detect an OBSS ICF-ICR exchange on the primary channel. This may be the case when an OBSS TXOP is detected on the primary channel. NPCA can be initiated by the detection of an OBSS TXOP on the primary channel. An NPCA AP can set BasicNAV and T_NPCA. T_NPCA can be set after receiving an OBSS ICR or after receiving an OBSS PPDU.

[0308] Afterwards, if the NPCA STA does not receive any kind of frame from the NPCA AP during a specific time interval (NPCASchedTimer), the NPCA STA may abort the NPCA. That is, the T_NPCA may be aborted before the end time of the initially configured N_TPCA. The end time of the T_NPCA of the NPCA AP may be the expiration time of the specific time interval (NPCASchedTimer).

[0309] An NPCA AP can participate in contention after BasicNAV is terminated on the primary channel, and can perform transmission (e.g., transmission of DL MU PPDU) based on the contention result. Here, transmission of DL MU PPDU can be performed through the entire bandwidth (P80 and S80).

[0310] FIG. 18 is a diagram illustrating an example of an operation related to an NPC TXOP within a period for an NPCA operation according to an embodiment of the present disclosure. FIG. 18 illustrates an example of NPC TXOPs within the period of an NPCA operation. FIG. 18 illustrates an example of a case where a CF-End is received in the primary channel, and then the NPCA AP sends an NTC over the NPCH.

[0311] Referring to FIG. 18, OBSS ICF, OBSS ICR, OBSS PPDU, OBSS BA, and OBSS CF-End can be transmitted in an 80 MHz bandwidth (P80). OBSS CF-End can indicate an interruption of OBSS TXOP.

[0312] An NPCA AP can detect an OBSS ICF-ICR exchange on the primary channel. This may be the case when an OBSS TXOP is detected on the primary channel. NPCA can be initiated by the detection of an OBSS TXOP on the primary channel. An NPCA AP can configure BasicNAV and T_NPCA. T_NPCA can be configured after receiving an OBSS ICR or after receiving an OBSS PPDU.

[0313] An NPCA STA can detect an OBSS ICF-ICR exchange on the primary channel. This may be the case when an OBSS TXOP is detected on the primary channel. NPCA can be initiated by the detection of an OBSS TXOP on the primary channel. An NPCA STA can set BasicNAV and T_NPCA. T_NPCA can be set after receiving an OBSS ICR or after receiving an OBSS PPDU.

[0314] An NPCA AP can acquire NPC TXOP#1 through EDCA contention on the anchor channel within the NPCH. Multiple data can be exchanged between the NPCA AP and the NPCA STA within NPC TXOP#1. For example, TF, response, NPCA PPDU, BA, etc. can be exchanged. After NPC TXOP#1, one or more NPC TXOPs (... NPC TXOP#N) can be established.

[0315] When CF-End is detected on the primary channel, the NPCA AP may abort BasicNAV. That is, BasicNAV may be aborted before the initially configured BasicNAV end point.

[0316] When CF-End is detected on the primary channel, the NPCA AP can transmit NTC and stop NPCA. That is, T_NPCA can be stopped before the end time of the initially configured N_TPCA. The end time of T_NPCA of the NPCA AP can be the time of NTC transmission.

[0317] When CF-End is detected on the primary channel, NPCA STA can stop BasicNAV. That is, BasicNAV can be stopped before the end time of the initially configured BasicNAV. When CF-End (OBSS CF-End) is not detected on the primary channel (when detection fails, when CF-End detection fails and NTC is detected), BasicNAV of NPCA STA can be maintained, in which case NPCA STA can reset BasicNAV based on CF-End of NPCA AP described later.

[0318] When CF-End is detected on the primary channel, the NPCA STA can stop NPCA. Or, when NTC is received, the NPCA STA can stop NPCA. That is, T_NPCA can be stopped before the end time of the initially set N_TPCA, and the end time of T_NPCA of the NPCA STA can be the time of detection of CF-End or the time of receiving NTC. That is, an STA that receives CF-End of the primary channel can immediately stop NPCA, and an STA that fails to receive CF-End of the primary channel can stop NPCA when it receives NTC on the NPCH.

[0319] After NPCA termination, the NPCA AP can transmit CF-End on the primary channel to induce a reset of the BasicNAV of NPCA STAs on the primary channel. The NPCA AP can use CF-End as an NTC to command / instruct NPCA termination and simultaneously induce a reset of the BasicNAV settings of NPCA STAs.

[0320] An RTS-CTS exchange can be performed between an NPCA AP and an NPCA STA that have returned to the primary channel. The NPCA AP can transmit MU-RTS over the entire bandwidth (P80 and S80). The NPCA STA can transmit CTS over the entire bandwidth (P80 and S80). Afterwards, the NPCA AP can perform transmission (e.g., transmission of DL MU PPDU) over the entire bandwidth (P80 and S80). The NPCA STA can transmit the corresponding BA over the entire bandwidth (P80 and S80).

[0321] FIGS. 19 and 20 are diagrams illustrating an example of an operation related to an NPC TXOP within a period for an NPCA operation according to an embodiment of the present disclosure. FIGS. 19 and 20 illustrate an example of NPC TXOPs within the duration of an NPCA operation. FIG. 19 illustrates an example of a case where a CF-End is received in the primary channel, and then the NPCA AP tries to send an NTC over the NPCH, but the NPCA truncation timer expires before finishing sending the NTC. FIG. 20 illustrates an example of an NTC transmission over the primary channel (or the entire bandwidth including the primary channel (entire channel)). The example of Fig. 20 can be applied to both cases where the NPCA interrupt timer is in operation, as in the example of Fig. 19, and / or where the NPCA interrupt timer is not in operation and the NPCA AP immediately terminates NPCA upon receiving CF-End, participates in contention on the primary channel, and then transmits NTC over the whole channel (CF-End reception in the primary channel, and then the NPCA AP sends NTC over the whole channel).

[0322] Referring to FIGS. 19 and 20, OBSS ICF, OBSS ICR, OBSS PPDU, OBSS BA, and OBSS CF-End can be transmitted in an 80 MHz bandwidth (P80). OBSS CF-End can indicate an interruption of OBSS TXOP.

[0323] An NPCA AP can detect an OBSS ICF-ICR exchange on the primary channel. This may be the case when an OBSS TXOP is detected on the primary channel. NPCA can be initiated by the detection of an OBSS TXOP on the primary channel. An NPCA AP can configure BasicNAV and T_NPCA. T_NPCA can be configured after receiving an OBSS ICR or after receiving an OBSS PPDU.

[0324] An NPCA STA can detect an OBSS ICF-ICR exchange on the primary channel. This may be the case when an OBSS TXOP is detected on the primary channel. NPCA can be initiated by the detection of an OBSS TXOP on the primary channel. An NPCA STA can set BasicNAV and T_NPCA. T_NPCA can be set after receiving an OBSS ICR or after receiving an OBSS PPDU.

[0325] An NPCA AP can acquire NPC TXOP#1 through EDCA contention on the anchor channel within the NPCH. Multiple data can be exchanged between the NPCA AP and the NPCA STA within NPC TXOP#1. For example, TF, response, NPCA PPDU, BA, etc. can be exchanged. After NPC TXOP#1, one or more NPC TXOPs (... NPC TXOP#N) can be established.

[0326] When CF-End is detected on the primary channel, the NPCA AP may abort BasicNAV. That is, BasicNAV may be aborted before the initially configured BasicNAV end point.

[0327] When CF-End is detected on the primary channel, the NPCA AP may transmit an NTC and abort NPCA, but the NPCA abort timer may expire before completing the transmission of the NTC as described above. In this case, the NPCA AP may terminate NPCA and return to the primary channel. That is, T_NPCA may be aborted before the end time of the initially configured N_TPCA, and the end time of T_NPCA of the NPCA AP may be the time of detection of CF-End or the time of reception of the NTC.

[0328] When CF-End is detected on the primary channel, the NPCA STA can stop BasicNAV. That is, BasicNAV can be stopped before the end time of the initially set BasicNAV. When CF-End (OBSS CF-End) is not detected on the primary channel (when detection fails, when detection of CF-End fails and NTC is detected), the BasicNAV of the NPCA STA can be maintained, and in this case, the NPCA STA can reset BasicNAV based on the CF-End of the NPCA AP. That is, as described above, the NPCA AP can transmit CF-End on the primary channel to induce reset of BasicNAV of NPCA STAs on the primary channel after NPCA termination. NPCA AP can use CF-End to command / instruct NPCA termination with NTC and simultaneously induce reset of BasicNAV settings of NPCA STA.

[0329] When CF-End is detected on the primary channel, the NPCA STA can stop NPCA. Or, when NTC is received, the NPCA STA can stop NPCA. That is, T_NPCA can be stopped before the end time of the initially set N_TPCA, and the end time of T_NPCA of the NPCA STA can be the time of detection of CF-End or the time of receiving NTC. That is, the STA that receives CF-End of the primary channel can immediately stop NPCA, and the STA that fails to receive CF-End of the primary channel can stop NPCA after listening to NTC on NPCH. However, if the NPCA AP returns to the primary channel first according to the NPCA stop timer as in the example of Fig. 19, the NPCA STA may not be aware of this.

[0330] Accordingly, as shown in the example of FIG. 20, the NPCA AP can transmit an NTC on the entire channel (full bandwidth) (P80 and S80) including the primary channel via EDCA after returning to the primary channel. The NTC can be used by the NPCA AP to initiate a TXOP on the entire channel (full bandwidth) (P80 and S80) including the primary channel. If the NTC cannot initiate a TXOP (for example, if CF-End is used as the NTC), the NPCA AP can initiate a new TXOP using an ICF such as MU-RTS, BSRP, or basic trigger frame by calling the EDCA procedure. In FIG. 20, a case where a TXOP is set to an NTC is exemplified. An MU-RTS can be transmitted after the NTC. The NPCA STA can receive the NTC and stop the NPCA.

[0331] An RTS-CTS exchange can be performed between an NPCA AP and an NPCA STA that have returned to the primary channel. The NPCA AP can transmit MU-RTS over the entire bandwidth (P80 and S80). The NPCA STA can transmit CTS over the entire bandwidth (P80 and S80). Afterwards, the NPCA AP can perform transmission (e.g., transmission of DL MU PPDU) over the entire bandwidth (P80 and S80). The NPCA STA can transmit the corresponding BA over the entire bandwidth (P80 and S80).

[0332] FIG. 21 illustrates an example of the operation of an AP according to one embodiment of the present disclosure. The flowchart of FIG. 21 illustrates an exemplary method that may be implemented according to the principles of the present disclosure, and various modifications may be made to the method illustrated in the flowchart. For example, although illustrated as a series of steps, various steps in each drawing may overlap, occur in parallel, occur in different orders, or occur multiple times. In other examples, steps may be omitted or replaced with other steps.

[0333] Referring to FIG. 21, in operation 2110 according to one embodiment of the present disclosure, an AP may identify a transmission associated with an overlapping basic service set (OBSS) on a primary channel.

[0334] In operation 2120 according to one embodiment of the present disclosure, the AP may set an NPCA time interval for non-primary channel access (NPCA) in a non-primary channel (NPCH).

[0335] In operation 2130 according to one embodiment of the present disclosure, the AP can identify a truncation of the NPCA before the expiration of the NPCA time interval.

[0336] In operation 2140 according to one embodiment of the present disclosure, the AP may transmit a control frame related to the suspension of the NPCA through the NPCH.

[0337] For more specific details on the operation of the AP according to one embodiment of the present disclosure described above, reference may be made to the description of various embodiments of the present disclosure described above.

[0338] FIG. 22 illustrates an example of the operation of an STA according to one embodiment of the present disclosure. The flowchart of FIG. 22 illustrates an exemplary method that may be implemented according to the principles of the present disclosure, and various modifications may be made to the method illustrated in the flowchart. For example, although illustrated as a series of steps, the various steps in each drawing may overlap, occur in parallel, occur in different orders, or occur multiple times. In other examples, steps may be omitted or replaced with other steps.

[0339] Referring to FIG. 22, in operation 2210 according to one embodiment of the present disclosure, an STA may identify a transmission associated with an overlapping basic service set (OBSS) on a primary channel.

[0340] In operation 2220 according to one embodiment of the present disclosure, the STA may set an NPCA time interval for non-primary channel access (NPCA) in a non-primary channel (NPCH).

[0341] In operation 2230 according to one embodiment of the present disclosure, the STA may receive a control frame related to truncation of the NPCA through the NPCH.

[0342] In operation 2240 according to one embodiment of the present disclosure, the STA may suspend the NPCA before the expiration of the NPCA time interval based on the control frame.

[0343] For more specific details on the operation of the STA according to one embodiment of the present disclosure described above, reference may be made to the description of various embodiments of the present disclosure described above.

[0344] The methods according to the embodiments described in the claims or specification of the present disclosure may be implemented in the form of hardware, software, or a combination of hardware and software.

[0345] When implemented in software, a computer-readable storage medium storing one or more programs (software modules) may be provided. The one or more programs stored in the computer-readable storage medium are configured for execution by one or more processors within an electronic device. The one or more programs include instructions that cause the electronic device to execute methods according to embodiments described in the claims or specification of the present disclosure.

[0346] These programs (software modules, software) may be stored in random access memory, non-volatile memory including flash memory, read only memory (ROM), electrically erasable programmable read only memory (EEPROM), magnetic disc storage device, compact disc ROM (CD-ROM), digital versatile discs (DVDs) or other forms of optical storage device, magnetic cassette. Or, they may be stored in a memory configured as a combination of some or all of these. In addition, each configuration memory may be included in multiple numbers.

[0347] Additionally, the program may be stored on an attachable storage device that is accessible via a communication network, such as the Internet, an intranet, a local area network (LAN), a wide local area network (WLAN), a storage area network (SAN), or a combination thereof. Such a storage device may be connected to a device implementing an embodiment of the present disclosure via an external port. Additionally, a separate storage device on the communication network may be connected to a device implementing an embodiment of the present disclosure.

[0348] In the specific embodiments of the present disclosure described above, components included in one embodiment are expressed singularly or plurally, depending on the specific embodiment presented. However, the singular or plural expressions are selected to suit the presented situation for convenience of explanation, and the present disclosure is not limited to singular or plural components. Components expressed in plural may be composed of singular elements, or components expressed in singular may be composed of plural elements.

[0349] Meanwhile, the embodiments of the present disclosure disclosed in this specification and drawings are merely specific examples to easily explain the technical content of the present disclosure and facilitate understanding of the present disclosure, and are not intended to limit the scope of the present disclosure. In other words, it will be apparent to those skilled in the art to which the present disclosure pertains that other modifications based on the technical concept of the present disclosure are possible. Furthermore, each of the above embodiments can be combined and operated as needed.

[0350] Meanwhile, the order of description in the drawings explaining the method of the present disclosure does not necessarily correspond to the order of execution, and the order of precedence may be changed or executed in parallel.

[0351] Alternatively, the drawings illustrating the method of the present disclosure may omit some components and include only some components without detracting from the essence of the present disclosure.

[0352] In addition, the method of the present disclosure may be implemented by combining some or all of the contents included in each embodiment within a scope that does not harm the essence of the present disclosure.

[0353] Various embodiments of the present disclosure have been described above. The foregoing description of the present disclosure is for illustrative purposes only, and the embodiments of the present disclosure are not limited to the disclosed embodiments. Those skilled in the art will appreciate that the present disclosure can be readily modified into other specific forms without altering the technical spirit or essential characteristics of the present disclosure. The scope of the present disclosure is indicated by the claims described below rather than the detailed description above, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included within the scope of the present disclosure.

Claims

1. In a method performed by an AP (access point) in a wireless LAN (local access network) system, A step of identifying a transmission associated with an overlapping basic service set (OBSS) on a primary channel; A step for setting an NPCA time interval for NPCA (non-primary channel access) in NPCH (non-primary channel); a step of identifying a truncation of the NPCA before the expiration of the NPCA time interval; and A method comprising the step of transmitting a control frame related to the suspension of the NPCA through the NPCH.

2. In paragraph 1, The above control frame: Contains a More Data subfield set to 0, or Contains a Type subfield set to 01 and a Subtype subfield set to 0001, or Contains a Type subfield set to 01, a Subtype subfield set to 0110, and a Control Frame Extension subfield set to one of the values ​​1011 through 1111. A method in which the Duration field of the control frame is set to 0, and the TA (transmitter address) field or the RA (receiver address) field of the control frame corresponds to a BSSID (basic service set identifier) ​​or an address of the AP.

3. In paragraph 1, The above control frame: A CF-End frame including a BSSID (TA) field corresponding to the address of the AP and a frame control field including a specific subfield, wherein the specific subfield indicates that the CF-End frame is related to the suspension of the NPCA or that the CF-End frame is for the NPCH, or A CTS (clear to send)-to-Self frame including a RA field corresponding to the address of the AP and a frame control field including a specific subfield, wherein the specific subfield indicates that the CTS-to-Self frame is related to the suspension of the NPCA or that the CTS-to-Self frame is for the NPCH, A method in which the control frame, which is the CF-End frame or the CTS-to-Self frame, does not change the NAV (network allocation vector) setting corresponding to the primary channel.

4. In paragraph 1, A method comprising the step of transmitting a control frame related to the interruption of the NPCA on the primary channel after the interruption of the NPCA on the channel including the primary channel and the NPCH, if it is identified that the control frame has not been successfully transmitted through the NPCH for a predetermined period of time.

5. In paragraph 1, A method comprising the step of returning to the primary channel before the expiration of the basic NAV corresponding to the primary channel after the interruption of the NPCA is identified.

6. In paragraph 1, A method in which an OBSS PPDU (physical layer protocol data unit) or an OBSS TXOP (transmission opportunity) is identified in the NPCH, and the remaining time of the NPCA time interval after the expiration of the OBSS PPDU or OBSS TXOP is less than a predefined threshold for a NPC (non-primary channel) TXOP, and an interruption of the NPCA is identified.

7. In paragraph 1, A specific channel for the channel access procedure related to the above NPCA is set up within the above NPCH, A method in which an interruption of the NPCA is identified when an OBSS management frame is detected on the specific channel.

8. In paragraph 1, After transmitting one or more of MU-RTS (multi user-request to send), BSRP (buffer status report poll) or basic trigger frames through the NPCH, if no response is received to one or more of the transmitted MU-RTS, BSRP or basic trigger frames during PIFS (priority inter frame space), the interruption of the NPCA is identified. A method in which an interruption of the NPCA is identified when an interruption of the OBSS TXOP of the primary channel is identified.

9. In the AP (access point) of a wireless LAN (local access network) system, Transmitter and receiver; and A processor connected to the transceiver, the processor comprising: Identify transmissions associated with an overlapping basic service set (OBSS) on a primary channel; Setting up NPCA time interval for NPCA (non-primary channel access) in NPCH (non-primary channel); Identifying truncation of the NPCA prior to expiration of the NPCA time interval; and An AP configured to transmit a control frame related to the suspension of the above NPCA through the above NPCH.

10. In paragraph 9, The above control frame: Contains a More Data subfield set to 0, or Contains a Type subfield set to 01 and a Subtype subfield set to 0001, or Contains a Type subfield set to 01, a Subtype subfield set to 0110, and a Control Frame Extension subfield set to one of the values ​​1011 through 1111. The Duration field of the above control frame is set to 0, and the TA (transmitter address) field or the RA (receiver address) field of the above control frame corresponds to the BSSID (basic service set identifier) ​​or the address of the AP.

11. In paragraph 9, The above control frame: A CF-End frame including a BSSID (TA) field corresponding to the address of the AP and a frame control field including a specific subfield, wherein the specific subfield indicates that the CF-End frame is related to the suspension of the NPCA or that the CF-End frame is for the NPCH, or A CTS (clear to send)-to-Self frame including a RA field corresponding to the address of the AP and a frame control field including a specific subfield, wherein the specific subfield indicates that the CTS-to-Self frame is related to the suspension of the NPCA or that the CTS-to-Self frame is for the NPCH, The control frame, which is the CF-End frame or the CTS-to-Self frame, does not change the NAV (network allocation vector) setting corresponding to the primary channel.

12. In paragraph 7, The AP is configured to transmit a control frame related to the interruption of the NPCA on the primary channel after the interruption of the NPCA on the channel including the primary channel and the NPCH, if the processor determines that the control frame has not been successfully transmitted through the NPCH for a predetermined period of time.

13. In paragraph 7, The above processor is: an AP configured to revert to the primary channel before expiration of the basic NAV corresponding to the primary channel after an outage of the NPCA is identified.

14. In a method performed by a STA (station) in a wireless LAN (local access network) system, A step of identifying a transmission associated with an overlapping basic service set (OBSS) on a primary channel; A step for setting an NPCA time interval for NPCA (non-primary channel access) in NPCH (non-primary channel); A step of receiving a control frame related to truncation of the NPCA through the NPCH; and A method comprising the step of stopping the NPCA before the expiration of the NPCA time interval based on the control frame.

15. In the STA (station) of a wireless LAN (local access network) system, Transmitter and receiver; and A processor connected to the transceiver, the processor comprising: Identify transmissions associated with an overlapping basic service set (OBSS) on a primary channel; Setting up NPCA time interval for NPCA (non-primary channel access) in NPCH (non-primary channel); Receiving a control frame related to truncation of the above NPCA through the above NPCH; and An STA configured to stop the NPCA before the expiration of the NPCA time interval based on the above control frame.

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