Channel switching technique for accessing non-primary channel

Abstract

The technical features of the present disclosure may relate to an apparatus or method performed in a wireless local area network (WLAN) system. For example, the present specification proposes a technical feature of suggesting an optimal timing for performing non-primary channel access (NPCA), depending on which PPDU format / type / version an overlapping basic service set (OBSS) traffic has. For example, a station (STA) may receive an OBSS signal. For example, on the basis of the OBSS signal, the STA may access an NPCA primary channel, attempt / perform switching to the NPCA primary channel, or trigger or perform an NPCA operation. The NPCA primary channel may be accessed on the basis of at least one of: a basic network allocation vector (NAV) set for the primary channel on the basis of the OBSS signal; and a wait time associated with the OBSS signal. For example, the wait time associated with the OBSS signal may be set on the basis of NAVWaitTime.

Description

Channel switch technique for accessing non-primary channels

[0001] The present disclosure relates to a wireless LAN system, and more particularly, to an improved method and device for accessing a channel other than a primary channel of a wireless LAN system.

[0002] Wireless local area networks (WLANs) have been improved in various ways. For example, the Extreme High Throughput (EHT) standard can utilize newly proposed increased bandwidth, an improved PHY layer protocol data unit (PPDU) structure, improved sequences, and Hybrid Automatic Repeat Request (HARQ) techniques. The EHT standard can also be referred to as the IEEE 802.11be standard.

[0003] The EHT specification supports high throughput and high data rates, which may include wide bandwidth (e.g., 160 / 320 MHz), 16 streams, and / or multi-link (or multi-band) operation.

[0004] In the EHT specification, wide bandwidth (e.g., 160 / 240 / 320 MHz) can be used to achieve high throughput. Preamble puncturing and multiple RU transmissions can also be used to efficiently utilize bandwidth.

[0005] WLAN systems can be further improved through the Ultra High Reliability (UHR) standard. The UHR system, also known as the IEEE 802.11bn standard, aims to support ultra-high reliability when transmitting signals to STAs. To achieve this, various technologies are being considered for UHR systems, including high throughput, low latency, and extended range support.

[0006] WLAN systems perform media access based on primary channels. For example, information about a primary channel with a bandwidth of 20 MHz is transmitted to multiple STAs via management frames, and any STA attempting to exchange frames can access the primary channel.

[0007] Currently, the 802.11 BSS Operating Channel can be configured based on a Primary Channel (PCH) and one or more Secondary Channels (SCHs). In order to transmit a frame based on the BSS operating channel, a back-off must always be performed on the PCH, and the back-off counter (BC) of the PCH must be 0. Accordingly, if the PCH is determined to be BUSY, the wireless channel / medium cannot be used. However, according to the prior art, only the PCH is BUSY, and even if the SCH (or non-primary channel) other than the PCH is in an IDLE state, the SCH cannot be used, which can significantly reduce medium efficiency. However, various conditions must be considered to trigger an operation to access the SCH (or non-primary channel).

[0008] This specification proposes various technical features. These technical features can be applied to various types of STAs / devices.

[0009] For example, this specification proposes a technical feature that suggests an optimal time when performing Non-Primary Channel Access (NPCA) depending on what PPDU format / type / version OBSS traffic (e.g., OBSS PPDU) has.

[0010] For example, a STA (station) can receive an OBSS (Overlapping Basic Service Set) signal. For example, based on the OBSS signal, the STA can perform access to an NPCA (Non-primary Channel Access) primary channel, attempt / perform a switch to the NPCA primary channel, or trigger / perform an NPCA operation. Access to the NPCA primary channel can be performed based on at least one of a Basic NAV (Network Allocation Vector) set for the primary channel based on the OBSS signal and a wait time related to the OBSS signal. The wait time related to the OBSS signal can be set based on NAVWaitTime.

[0011] The technical features described in this specification can produce various advantageous effects. For example, the NPCA triggering condition proposed in this specification can acquire the information necessary for performing NPCA at the earliest possible time, depending on the PPDU format of OBSS traffic. Furthermore, the technical features proposed in this specification allow the STA performing NPCA to perform NPCA for the longest possible time by switching to a non-primary channel at the earliest or optimal time based on the information acquired by the STA.

[0012] Figure 1 illustrates an example of a transmitting device and / or a receiving device of the present specification.

[0013] Figure 2 is a conceptual diagram showing the structure of a wireless local area network (WLAN).

[0014] Figure 3 is a diagram illustrating a general link setup process.

[0015] Figure 4 illustrates one embodiment of a multi-link (ML).

[0016] Figure 5 illustrates a PPDU transmitted / received by an STA of this specification.

[0017] Figure 6 is a diagram showing the layout of resource units (RUs) used for 20MHz PPDU.

[0018] Figure 7 is a diagram showing the layout of resource units (RUs) used for 40MHz PPDU.

[0019] Figure 8 is a diagram showing the layout of resource units (RUs) used for 80MHz PPDU.

[0020] Figure 9 shows the operation according to UL-MU.

[0021] Figure 10 shows an example of channels used / supported / defined within the 2.4 GHz band.

[0022] Figure 11 illustrates an example of channels used / supported / defined within the 5 GHz band.

[0023] Figure 12 illustrates an example of channels used / supported / defined within the 6 GHz band.

[0024] Figure 13 shows an example of a header of a MAC frame.

[0025] FIG. 14 illustrates a modified example of a transmitting device and / or a receiving device of the present specification.

[0026] Figure 15 illustrates an example of NAV (network allocation vector) settings.

[0027] Figure 16 shows an example related to primary channel, secondary channel, and channel extension / bonding.

[0028] Figure 17 relates to an example of channel access related to an 80 MHz channel.

[0029] Figure 18 illustrates an example of the SCA process.

[0030] Figure 19 is an example of a network topology related to an example of this specification.

[0031] Figure 20 illustrates an example related to Case 2-1.

[0032] Figure 21 is a procedure flow diagram related to a transmitting STA.

[0033] Figure 22 is a procedure flow diagram related to the receiving STA.

[0034] Figure 23 is another flowchart illustrating an example of the present specification.

[0035] Figure 24 is another flowchart illustrating an example of this specification.

[0036] Figure 25 illustrates an example related to channelization.

[0037] Figure 26 illustrates an example of SCA / NPCA performance at 320 MHz.

[0038] Figure 27 illustrates an example of SCA / NPCA performance at 320 MHz.

[0039] As used herein, "A or B" can mean "only A," "only B," or "both A and B." In other words, as used herein, "A or B" can be interpreted as "A and / or B." For example, as used herein, "A, B or C" can mean "only A," "only B," "only C," or "any combination of A, B and C."

[0040] As used herein, a slash ( / ) or a comma can mean "and / or." For example, "A / B" can mean "A and / or B." Accordingly, "A / B" can mean "only A," "only B," or "both A and B." For example, "A, B, C" can mean "A, B, or C."

[0041] In this specification, "at least one of A and B" may mean "only A", "only B" or "both A and B". Additionally, in this specification, the expressions "at least one of A or B" or "at least one of A and / or B" may be interpreted identically to "at least one of A and B".

[0042] In addition, parentheses used in this specification may mean "for example". Specifically, when it is indicated as "control information (UHR-Signal field)", the "UHR-Signal field" may be proposed as an example of "control information". In other words, the "control information" in this specification is not limited to the "UHR-Signal field", and the "UHR-Signal field" may be proposed as an example of "control information". In addition, even when it is indicated as "control information (UHR-Signal field)", the "UHR-Signal field" may be proposed as an example of "control information".

[0043] Additionally, as used herein, "a / an" can mean "at least one" or "one or more." Additionally, terms ending in "(s)" can mean "at least one" or "one or more."

[0044] Additionally, the expressions "based on" or "on the basis of" or "according to" used herein mean "based at least in part on" and not "based solely on".

[0045] Technical features individually described in a single drawing in this specification may be implemented individually or simultaneously.

[0046] The following examples of this specification can be applied to various wireless communication systems. For example, the following examples of this specification can be applied to wireless local area network (WLAN) systems. For example, the present specification can be applied to the IEEE 802.11a / g / n / ac / ax / be / bn standards. In addition, the examples of this specification can be applied to the Ultra High Reliability (UHR) standard or the next-generation wireless LAN standard that enhances IEEE 802.11bn. In addition, the examples of this specification can be applied to mobile communication systems. For example, the examples of this specification can be applied to mobile communication systems based on Long Term Evolution (LTE) and its evolution based on the 3rd Generation Partnership Project (3GPP) standard.

[0047] In order to explain the technical features of this specification, the technical features to which this specification can be applied are described below.

[0048] Figure 1 illustrates an example of a transmitting device and / or a receiving device of the present specification.

[0049] An example of FIG. 1 can perform various technical features described below. FIG. 1 relates to at least one STA (station). For example, the STA (110, 120) of the present specification may also be referred to by various names such as a mobile terminal, a wireless device, a Wireless Transmit / Receive Unit (WTRU), a User Equipment (UE), a Mobile Station (MS), a Mobile Subscriber Unit, or simply a user. The STA (110, 120) of the present specification may also be referred to by various names such as a network, a base station, a Node-B, an access point (AP), a repeater, a router, a relay, etc. The STA (110, 120) of the present specification may also be referred to by various names such as a receiving apparatus, a transmitting apparatus, a receiving STA, a transmitting STA, a receiving device, a transmitting device, etc.

[0050] For example, STA (110, 120) may perform the role of an AP (access point) or a non-AP role. That is, STA (110, 120) of the present specification may perform the functions of an AP and / or a non-AP. In the present specification, AP may also be indicated as an AP STA.

[0051] The STA (110, 120) of this specification can support various communication standards other than the IEEE 802.11 standard. For example, it can support communication standards according to the 3GPP standard (e.g., LTE, LTE-A, 5G NR standard). In addition, the STA of this specification can be implemented in various devices such as mobile phones, vehicles, and personal computers. In addition, the STA of this specification can support communication for various communication services such as voice calls, video calls, data communications, and autonomous driving (Self-Driving, Autonomous-Driving).

[0052] In this specification, STA (110, 120) may include a medium access control (MAC) and a physical layer interface for a wireless medium that follow the provisions of the IEEE 802.11 standard.

[0053] Based on the sub-drawing (a) of Fig. 1, STA (110, 120) is described as follows.

[0054] The first STA (110) may include a processor (111), a memory (112), and a transceiver (113). The illustrated processor, memory, and transceiver may each be implemented as separate chips, or at least two blocks / functions may be implemented through a single chip.

[0055] The transceiver (113) of the first STA performs signal transmission and reception operations. Specifically, it can transmit and receive IEEE 802.11 packets (e.g., IEEE 802.11a / b / g / n / ac / ax / be, etc.).

[0056] For example, the first STA (110) can perform the intended operation of the AP. For example, the processor (111) of the AP can receive a signal through the transceiver (113), process the received signal, generate a transmission signal, and perform control for signal transmission. The memory (112) of the AP can store a signal received through the transceiver (113) (i.e., a reception signal) and store a signal to be transmitted through the transceiver (i.e., a transmission signal).

[0057] For example, the second STA (120) can perform the intended operation of a non-AP STA. For example, the transceiver (123) of the non-AP performs signal transmission and reception operations. Specifically, it can transmit and receive IEEE 802.11 packets (e.g., IEEE 802.11a / b / g / n / ac / ax / be, etc.).

[0058] For example, the processor (121) of the Non-AP STA can receive a signal through the transceiver (123), process the received signal, generate a transmission signal, and perform control for signal transmission. The memory (122) of the Non-AP STA can store a signal received through the transceiver (123) (i.e., a reception signal) and store a signal to be transmitted through the transceiver (i.e., a transmission signal).

[0059] For example, in the specification below, the operation of a device indicated as AP may be performed in the first STA (110) or the second STA (120). For example, if the first STA (110) is an AP, the operation of the device indicated as AP may be controlled by the processor (111) of the first STA (110), and a related signal may be transmitted or received through a transceiver (113) controlled by the processor (111) of the first STA (110). In addition, control information related to the operation of the AP or a transmission / reception signal of the AP may be stored in the memory (112) of the first STA (110). In addition, when the second STA (110) is an AP, the operation of the device indicated as an AP is controlled by the processor (121) of the second STA (120), and a related signal can be transmitted or received through a transceiver (123) controlled by the processor (121) of the second STA (120). In addition, control information related to the operation of the AP or the transmission / reception signal of the AP can be stored in the memory (122) of the second STA (110).

[0060] For example, in the specification below, the operation of a device indicated as a non-AP (or User-STA) may be performed in the STA (110) or the second STA (120). For example, if the second STA (120) is a non-AP, the operation of the device indicated as a non-AP may be controlled by the processor (121) of the second STA (120), and a related signal may be transmitted or received through a transceiver (123) controlled by the processor (121) of the second STA (120). In addition, control information related to the operation of the non-AP or the transmission / reception signal of the AP may be stored in the memory (122) of the second STA (120). For example, if the first STA (110) is a non-AP, the operation of a device indicated as a non-AP is controlled by the processor (111) of the first STA (110), and a related signal may be transmitted or received through a transceiver (113) controlled by the processor (111) of the first STA (120). In addition, control information related to the operation of the non-AP or the transmission / reception signal of the AP may be stored in the memory (112) of the first STA (110).

[0061] In the following specification, devices called (transmitting / receiving) STA, first STA, second STA, STA1, STA2, AP, first AP, second AP, AP1, AP2, (transmitting / receiving) Terminal, (transmitting / receiving) device, (transmitting / receiving) apparatus, network, etc. may refer to the STA (110, 120) of FIG. 1. For example, devices indicated as (transmitting / receiving) STA, first STA, second STA, STA1, STA2, AP, first AP, second AP, AP1, AP2, (transmitting / receiving) Terminal, (transmitting / receiving) device, (transmitting / receiving) apparatus, network, etc. without specific drawing symbols may also refer to the STA (110, 120) of FIG. 1. For example, in the example below, the operation of various STAs transmitting and receiving signals (e.g., PPPDU) may be performed by the transceiver (113, 123) of FIG. 1. In addition, in the example below, the operation of various STAs generating transmission and reception signals or performing data processing or calculations in advance for transmission and reception signals may be performed by the processor (111, 121) of FIG. 1.For example, an example of an operation for generating a transmission / reception signal or performing data processing or operation in advance for a transmission / reception signal may include 1) an operation for determining / obtaining / configuring / computing / decoding / encoding bit information of a subfield (SIG, STF, LTF, Data) field included in a PPDU, 2) an operation for determining / configuring / obtaining time resources or frequency resources (e.g., subcarrier resources) used for a subfield (SIG, STF, LTF, Data) field included in a PPDU, 3) an operation for determining / configuring / obtaining a specific sequence (e.g., a pilot sequence, an STF / LTF sequence, an extra sequence applied to SIG) used for a subfield (SIG, STF, LTF, Data) field included in a PPDU, 4) a power control operation and / or a power saving operation applied to an STA, 5) an operation related to determining / obtaining / configuring / computing / decoding / encoding an ACK signal, etc. Additionally, in the examples below, various information (e.g., information related to fields / subfields / control fields / parameters / power, etc.) used by various STAs for determining / acquiring / configuring / computing / decoding / encoding transmission / reception signals can be stored in the memory (112, 122) of FIG. 1.

[0062] The device / STA of the sub-drawing (a) of the above-described FIG. 1 can be modified as in the sub-drawing (b) of FIG. 1. Hereinafter, the STA (110, 120) of the present specification will be described based on the sub-drawing (b) of FIG. 1.

[0063] For example, the transceiver (113, 123) illustrated in sub-drawing (b) of FIG. 1 may perform the same function as the transceiver illustrated in sub-drawing (a) of FIG. 1 described above. For example, the processing chip (114, 124) illustrated in sub-drawing (b) of FIG. 1 may include a processor (111, 121) and a memory (112, 122). The processor (111, 121) and the memory (112, 122) illustrated in sub-drawing (b) of FIG. 1 may perform the same function as the processor (111, 121) and the memory (112, 122) illustrated in sub-drawing (a) of FIG. 1 described above.

[0064] The mobile terminal, wireless device, Wireless Transmit / Receive Unit (WTRU), User Equipment (UE), Mobile Station (MS), Mobile Subscriber Unit, user, user STA, network, Base Station, Node-B, Access Point (AP), repeater, router, relay, receiving device, transmitting device, receiving STA, transmitting STA, receiving Device, transmitting Device, receiving Apparatus, and / or transmitting Apparatus described below may refer to the STA (110, 120) illustrated in the sub-drawings (a) / (b) of FIG. 1, or may refer to the processing chip (114, 124) illustrated in the sub-drawing (b) of FIG. 1. That is, the technical feature of the present specification may be performed in the STA (110, 120) illustrated in the sub-drawings (a) / (b) of FIG. 1, or may be performed only in the processing chip (114, 124) illustrated in the sub-drawings (b) of FIG. 1. For example, the technical feature that the transmitting STA transmits a control signal may be understood as a technical feature that the control signal generated in the processor (111, 121) illustrated in the sub-drawings (a) / (b) of FIG. 1 is transmitted through the transceiver (113, 123) illustrated in the sub-drawings (a) / (b) of FIG. 1. Alternatively, the technical feature that the transmitting STA transmits a control signal may be understood as a technical feature that the control signal to be transmitted to the transceiver (113, 123) is generated in the processing chip (114, 124) illustrated in the sub-drawings (b) of FIG. 1.

[0065] For example, the technical feature of a receiving STA receiving a control signal can be understood as a technical feature of a control signal being received by a transceiver (113, 123) illustrated in sub-drawing (a) of FIG. 1. Alternatively, the technical feature of a receiving STA receiving a control signal can be understood as a technical feature of a control signal received by a transceiver (113, 123) illustrated in sub-drawing (a) of FIG. 1 being acquired by a processor (111, 121) illustrated in sub-drawing (a) of FIG. 1. Alternatively, the technical feature of a receiving STA receiving a control signal can be understood as a technical feature of a control signal received by a transceiver (113, 123) illustrated in sub-drawing (b) of FIG. 1 being acquired by a processing chip (114, 124) illustrated in sub-drawing (b) of FIG.

[0066] Referring to the sub-drawing (b) of FIG. 1, software code (115, 125) may be included in the memory (112, 122). The software code (115, 125) may include instructions that control the operation of the processor (111, 121). The software code (115, 125) may be included in various programming languages.

[0067] The processor (111, 121) or processing chip (114, 124) illustrated in FIG. 1 may include an application-specific integrated circuit (ASIC), another chipset, a logic circuit, and / or a data processing device. The processor may be an application processor (AP). For example, the processor (111, 121) or processing chip (114, 124) illustrated in FIG. 1 may include at least one of a digital signal processor (DSP), a central processing unit (CPU), a graphics processing unit (GPU), and a modem (modulator and demodulator). For example, the processor (111, 121) or processing chip (114, 124) illustrated in FIG. 1 may be a SNAPDRAGON® series processor manufactured by Qualcomm®, an EXYNOS® series processor manufactured by Samsung®, an A series processor manufactured by Apple®, a HELIO® series processor manufactured by MediaTek®, an ATOM® series processor manufactured by INTEL®, or an enhanced processor thereof.

[0068] In this specification, uplink may mean a link for communication from a non-AP STA to an AP STA, and uplink PPDU / packet / signal, etc. may be transmitted through the uplink. In addition, in this specification, downlink may mean a link for communication from an AP STA to a non-AP STA, and downlink PPDU / packet / signal, etc. may be transmitted through the downlink.

[0069] Figure 2 is a conceptual diagram showing the structure of a wireless local area network (WLAN).

[0070] The upper part of Figure 2 shows the structure of the infrastructure BSS (basic service set) of IEEE (institute of electrical and electronic engineers) 802.11.

[0071] Referring to the top of FIG. 2, the wireless LAN system may include one or more infrastructure BSSs (200, 205) (hereinafter, BSS). The BSSs (200, 205) are a collection of APs and STAs, such as an access point (AP) 225 and a station (STA1, 200-1), that have successfully synchronized and can communicate with each other, and are not a concept that designates a specific area. The BSS (205) may also include one or more STAs (205-1, 205-2) that can be associated with one AP (230).

[0072] A BSS may include at least one STA, an AP (225, 230) providing a distribution service, and a distribution system (DS, 210) connecting multiple APs.

[0073] A distributed system (210) can connect multiple BSSs (200, 205) to implement an extended service set (ESS) 240. An ESS (240) can be used as a term to indicate a network formed by connecting one or more APs through the distributed system (210). APs included in a single ESS (240) can have the same SSID (service set identification).

[0074] The portal (portal, 220) can act as a bridge to connect a wireless LAN network (IEEE 802.11) to another network (e.g., 802.X).

[0075] In a BSS such as the upper part of Fig. 2, a network between APs (225, 230) and a network between APs (225, 230) and STAs (200-1, 205-1, 205-2) can be implemented. However, it may also be possible to establish a network and perform communication between STAs without an AP (225, 230). A network that establishes a network and performs communication between STAs without an AP (225, 230) is defined as an ad-hoc network or an independent basic service set (IBSS).

[0076] The bottom of Figure 2 is a conceptual diagram showing IBSS.

[0077] Referring to the bottom of Fig. 2, the IBSS is a BSS that operates in ad-hoc mode. Since the IBSS does not include an AP, there is no centralized management entity. That is, in the IBSS, the STAs (250-1, 250-2, 250-3, 255-4, 255-5) are managed in a distributed manner. In the IBSS, all STAs (250-1, 250-2, 250-3, 255-4, 255-5) can be mobile STAs, and access to the distributed system is not permitted, forming a self-contained network.

[0078] Figure 3 is a diagram illustrating a general link setup process.

[0079] In step S310, the STA may perform a network discovery operation. This network discovery operation may include scanning by the STA. That is, for the STA to access the network, it must find a network it can join. Before joining a wireless network, the STA must identify compatible networks. The process of identifying networks in a specific area is called scanning. Scanning methods include active scanning and passive scanning.

[0080] Figure 3 illustrates a network discovery operation that includes an active scanning process as an example. In active scanning, an STA performing scanning transmits a probe request frame to discover which APs exist in the vicinity while moving between channels and waits for a response. A responder transmits a probe response frame to the STA that transmitted the probe request frame in response to the probe request frame. Here, the responder may be the STA that last transmitted a beacon frame in the BSS of the channel being scanned. In a BSS, the AP transmits the beacon frame, so the AP becomes the responder. In an IBSS, the STAs within the IBSS take turns transmitting beacon frames, so the responder is not constant. For example, an STA that transmits a probe request frame on channel 1 and receives a probe response frame on channel 1 can store BSS-related information included in the received probe response frame and move to the next channel (e.g., channel 2) to perform scanning (i.e., transmitting and receiving probe requests / responses on channel 2) in the same manner.

[0081] Although not shown in the example of FIG. 3, the scanning operation can also be performed in a passive scanning manner. An STA performing scanning based on passive scanning can wait for a beacon frame while moving between channels. A beacon frame is one of the management frames in IEEE 802.11. It announces the presence of a wireless network and is periodically transmitted so that the scanning STA can find the wireless network and participate in the wireless network. In the BSS, the AP periodically transmits the beacon frame, and in the IBSS, the STAs within the IBSS take turns transmitting the beacon frame. When the scanning STA receives a beacon frame, it stores the information about the BSS included in the beacon frame and moves to another channel, recording the beacon frame information on each channel. An STA that receives a beacon frame can store the BSS-related information included in the received beacon frame, move to the next channel, and perform scanning on the next channel in the same manner.

[0082] An STA that discovers a network can perform an authentication process through step S320. This authentication process may be referred to as the first authentication process to clearly distinguish it from the security setup operation of step S340 described below. The authentication process of S320 may include a process in which the STA transmits an authentication request frame to the AP, and the AP responds by transmitting an authentication response frame to the STA. The authentication frame used for the authentication request / response corresponds to a management frame.

[0083] 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.

[0084] An STA can transmit an authentication request frame to an AP. The AP can determine whether to grant authentication to the STA based on the information contained in the received authentication request frame. The AP can provide the result of the authentication process to the STA via an authentication response frame.

[0085] A successfully authenticated STA may perform an association process based on step S330. The association process includes a process in which the STA transmits an association request frame to the AP, and the AP transmits an association response frame to the STA in response. For example, the association request frame may include information related to various capabilities, such as a beacon listen interval, a service set identifier (SSID), supported rates, supported channels, RSN, mobility domain, supported operating classes, a Traffic Indication Map Broadcast request, and interworking service capabilities. For example, the association response frame may contain 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.

[0086] In step S340, the STA may perform a security setup process. The security setup process of step S340 may include, for example, a process of setting up a private key through a four-way handshaking using an Extensible Authentication Protocol over LAN (EAPOL) frame.

[0087] Figure 4 illustrates one embodiment of a multi-link (ML).

[0088] As illustrated in FIG. 4, multiple multi-link devices (MLDs) can communicate over a remote link. The MLDs can be categorized into AP MLDs including multiple AP STAs and non-AP MLDs including multiple non-AP STAs. That is, the AP MLD can include affiliated APs (i.e., AP STAs), and the non-AP MLD can include affiliated STAs (i.e., non-AP STAs, or user-STAs).

[0089] A multilink may include a first link and a second link, and different channels / subchannels / frequency resources may be allocated to the first and second links. The first and second multilinks may be identified through a link ID of 4 bits (or other n bits). The first and second links may be configured in the same 2.4 GHz, 5 GHz, or 6 GHz band. Alternatively, the first link and the second link may be configured in different bands.

[0090] The AP MLD of FIG. 4 includes three affiliated APs. In the example of FIG. 4, AP1 may operate in the 2.4 GHz band, AP2 may operate in the 5 GHz band, and AP3 may operate in the 6 GHz band. In the example of FIG. 4, the first link in which AP1 and non-AP1 operate may be defined as a channel / subchannel / frequency resource within the 2.4 GHz band. Furthermore, in the example of FIG. 4, the second link in which AP2 and non-AP2 operate may be defined as a channel / subchannel / frequency resource within the 5 GHz band. Furthermore, in the example of FIG. 4, the third link in which AP3 and non-AP3 operate may be defined as a channel / subchannel / frequency resource within the 6 GHz band.

[0091] In the example of FIG. 4, AP1 may initiate a multi-link setup procedure (ML setup procedure) by transmitting an Association Request frame to non-AP STA1. In the example of FIG. 4, non-AP STA1 may transmit an Association Response frame in response to the Association Request frame. Each AP (e.g., AP1 / 2 / 3) illustrated in FIG. 4 may be identical to the AP illustrated in FIG. 1 and / or FIG. 2, and each non-AP (e.g., non-AP1 / 2 / 3) illustrated in FIG. 4 may be identical to the STA (i.e., user-STA or non-AP STA) illustrated in FIG. 1 and / or FIG. 2.

[0092] The specific features of this specification are not limited to the specific features of FIG. 4. That is, the number of links can be defined in various ways, and multiple links can be defined in various ways within at least one band.

[0093] FIG. 5 illustrates a PPDU (physical protocol data unit or physical layer (PHY) protocol data unit) transmitted / received by an STA of this specification.

[0094] The STA (e.g., AP STA, non-AP STA, AP MLD, non-AP MLD) of the present specification can transmit and / or receive the PPDU of FIG. 5. The PPDU described in the present specification may have, for example, the structure of FIG. 5. In addition, the PPDU described in the present specification may be called by various names such as a transmission PPDU, a reception PPDU, a first type PPDU, or an Nth type PPDU, etc. The PPDU described in the present specification can be used in a WLAN system defined according to IEEE 802.11bn and / or a next-generation WLAN system that improves IEEE 802.11bn.

[0095] The PPDU of FIG. 5 may be related to various PPDU types used in a UHR system. For example, the example of FIG. 5 may be used for at least one of a single-user (SU) mode / type / transmission, a multi-user (MU) mode / type / transmission, and a null data packet (NDP) mode / type / transmission related to channel sounding. For example, if the example of FIG. 5 is related to NDP, the Data field illustrated may be omitted. If the PPDU of FIG. 5 is used for a trigger-based (TB) mode, the UHR-SIG of FIG. 5 may be omitted. In other words, an STA that has received a trigger frame for UL-MU (Uplink-MU) communication may transmit a PPDU with the UHR-SIG omitted in the example of FIG. 5.

[0096] In FIG. 5, L-STF or UHR-LTF may be called a preamble or physical preamble, and may be generated / transmitted / received / acquired / decoded in the physical layer (included in the transmitting / receiving STA).

[0097] Each block illustrated in Fig. 5 may be called a field / subfield / signal, etc. The names of these fields / subfields / signals may be, as illustrated in Fig. 5, L-STF (legacy short training field), L-LTF (legacy long training field), L-SIG (legacy signal), RL-SIG (repeated L-SIG), U-SIG (Universal Signal), UHR-SIG (UHR-signal), etc.

[0098] The subcarrier spacing of the L-STF, L-LTF, L-SIG, RL-SIG, U-SIG, and UHR-SIG fields in FIG. 5 may be set to 312.5 kHz, and the subcarrier spacing of the UHR-STF, UHR-LTF, and Data fields may be set to 78.125 kHz. That is, the tone index (or subcarrier index) of the L-STF, L-LTF, L-SIG, RL-SIG, U-SIG, and UHR-SIG fields may be expressed in units of 312.5 kHz, and the tone index (or subcarrier index) of the UHR-STF, UHR-LTF, and Data fields may be expressed in units of 78.125 kHz.

[0099] In the PPDU of Fig. 5, L-LTF and L-STF may be identical to conventional fields (e.g., non-HT LTF and non-HT STF defined in conventional WLAN standards).

[0100] The L-SIG field of FIG. 5 may include, for example, 24 bits of bit information. For example, the 24 bits of information may include a 4 bit Rate field, a 1 bit Reserved bit, a 12 bit Length field, a 1 bit Parity bit, and a 6 bit Tail bit. For example, the 12 bit Length field may include information about the length or time duration of the PPDU. For example, the value of the 12 bit Length field may be determined based on the type of the PPDU. For example, if the PPDU is a non-HT (non-High Throughput), HT (High Throughput), VHT (Very High Throughput) PPDU, or an EHT (extremely high throughput) PPDU or UHR PPDU, the value of the Length field may be determined as a multiple of 3. For example, if the PPDU is a HE PPDU, the value of the Length field may be determined as "a multiple of 3 + 1" or "a multiple of 3 + 2". In other words, for non-HT, HT, VHT PPDU, EHT PPDU, UHR PPDU, the value of the Length field can be determined as a multiple of 3, and for HE (High Efficiency) PPDU, the value of the Length field can be determined as "a multiple of 3 + 1" or "a multiple of 3 + 2". In other words, the Length field in an UHR PPDU is set to a value satisfying the condition that the remainder is zero when LENGTH is divided by 3.

[0101] For example, (non-AP and AP) STAs can apply BCC encoding based on a code rate of 1 / 2 to the 24 bits of information in the L-SIG field. Then, the transmitting STA can obtain 48 BCC coded bits. BPSK modulation can be applied to the 48 coded bits to generate 48 BPSK symbols. The transmitting STA can map the 48 BPSK symbols to positions excluding the pilot subcarriers {subcarrier index -21, -7, +7, +21} and the DC subcarrier {subcarrier index 0}. As a result, the 48 BPSK symbols can be mapped to subcarrier indices -26 to -22, -20 to -8, -6 to -1, +1 to +6, +8 to +20, and +22 to +26. The transmitting STA can additionally map the signal {-1, -1, -1, 1} to the subcarrier indices {-28, -27, +27, +28}. The above signal can be used for channel estimation for the frequency domain corresponding to {-28, -27, +27, +28}.

[0102] For example, (non-AP and AP) STA can generate RL-SIG, which is generated in the same manner as L-SIG. BPSK modulation can be applied to RL-SIG. Receiving (non-AP and AP) STA can determine whether the received PPDU is a HE PPDU, EHT PPDU, or UHR PPDU based on the presence of RL-SIG. In other words, if RL-SIG is present, receiving (non-AP and AP) STA can determine whether the received PPDU is one of HE PPDU, EHT PPDU, or UHR PPDU. In other words, if RL-SIG is not present, receiving (non-AP and AP) STA can determine whether the received PPDU is one of non-HT PPDU, HT PPDU, or VHT PPDU. In other words, the RL-SIG field is a repeat of the L-SIG field and is used to differentiate an UHR PPDU from a non-HT PPDU, HT PPDU, and VHT PPDU.

[0103] After the RL-SIG in Fig. 5, a U-SIG (Universal SIG) may be inserted. The U-SIG may be called by various names such as the first SIG field, the first SIG, the first type SIG, the control signal, the control signal field, the first (type) control signal, the common control field, and the common control signal.

[0104] A U-SIG can contain N bits of information and can include information for identifying the type of EHT PPDU. For example, a U-SIG can be formed based on two symbols (e.g., two consecutive OFDM symbols). Each symbol (e.g., an OFDM symbol) for a U-SIG can have a duration of 4 microseconds. Each symbol of a U-SIG can be used to transmit 26 bits of information. For example, each symbol of a U-SIG can be transmitted and received based on 52 data tones and 4 pilot tones.

[0105] For example, A bit information (e.g., 52 uncoded bits) can be transmitted through U-SIG, and the first symbol of U-SIG can transmit the first X bits of information (e.g., 26 uncoded bits) out of the total A bit information, and the second symbol of U-SIG can transmit the remaining Y bits of information (e.g., 26 uncoded bits) out of the total A bit information. For example, the transmitting STA can obtain 26 uncoded bits included in each U-SIG symbol. The transmitting STA can perform convolutional encoding (i.e., BCC encoding) based on a rate of R=1 / 2 to generate 52 coded bits, and perform interleaving on the 52 coded bits. The transmitting STA can perform BPSK modulation on the interleaved 52 coded bits to generate 52 BPSK symbols allocated to each U-SIG symbol. A single U-SIG symbol can be transmitted based on 56 tones (subcarriers) from subcarrier index -28 to subcarrier index +28, excluding DC index 0. The 52 BPSK symbols generated by the transmitting STA can be transmitted based on the remaining tones (subcarriers) excluding the pilot tones -21, -7, +7, and +21.

[0106] For example, A bit information (e.g., 52 uncoded bits) transmitted by U-SIG may include a CRC field (e.g., a 4-bit long field) and a tail field (e.g., a 6-bit long field). The CRC field and the tail field may be transmitted through the second symbol of the U-SIG. The CRC field may be generated based on 26 bits allocated to the first symbol of the U-SIG and the remaining 16 bits excluding the CRC / tail field within the second symbol, and may be generated based on a conventional CRC calculation algorithm. In addition, the tail field may be used to terminate the trellis of the convolutional decoder and may be set to, for example, "000000".

[0107] The A bit information (e.g., 52 uncoded bits) transmitted by the U-SIG (or U-SIG field) can be divided into version-independent bits and version-dependent bits. For example, the size of the version-independent bits can be fixed or variable. For example, the version-independent bits can be assigned only to the first symbol of the U-SIG, or the version-independent bits can be assigned to both the first symbol and the second symbol of the U-SIG. For example, the version-independent bits and the version-dependent bits can be called by various names, such as the first control bit and the second control bit.

[0108] For example, the version-independent bits of the U-SIG may include a 3-bit PHY version identifier. For example, the 3-bit PHY version identifier may include information related to the PHY version of the transmitted and received PPDU. For example, a first value (e.g., a value of 000) of the 3-bit PHY version identifier may indicate that the transmitted and received PPDU is an EHT PPDU. In addition, a second value (e.g., a value of 001) of the 3-bit PHY version identifier may indicate that the transmitted and received PPDU is an UHR PPDU.

[0109] In other words, when the (AP / non-AP) STA transmits an EHT PPDU, it can set the 3-bit PHY version identifier to the first value. In other words, the receiving (AP / non-AP) STA can determine that the received PPDU is an EHT PPDU based on the PHY version identifier having the first value, and can determine that the received PPDU is an UHR PPDU based on the PHY version identifier having the second value.

[0110] For example, the version-independent bits of U-SIG may include a 1-bit UL / DL flag field. The first value of the 1-bit UL / DL flag field relates to UL communication, and the second value of the UL / DL flag field relates to DL communication.

[0111] For example, the version-independent bits of U-SIG may contain information about the length of the TXOP and information about the BSS color ID.

[0112] For example, if a UHR PPDU is classified into various types (e.g., a type related to SU transmission (performed based on UL or DL), a type related to DL transmission, a type related to NDP transmission, a type related to DL non-MU-MIMO, a type related to DL MU-MIMO, a type related to Multi-AP operation, a type related to CBF (Coordinated beamforming), SR (Spatial Reuse), a type related to C-OFDMA (Coordinated OFDMA), a type related to C-TDMA (Coordinated TDMA)), information about the type of the EHT PPDU (e.g., 2-bit or 3-bit information) can be included in the version-dependent bits of the U-SIG.

[0113] For example, U-SIG may include 1) a bandwidth field including information about bandwidth, 2) a field including information about a Modulation and Coding Scheme (MCS) technique applied to UHR-SIG, 3) an indication field including information about whether a dual subcarrier modulation (DCM) technique is applied to UHR-SIG, 4) a field including information about the number of symbols used for UHR-SIG, 5) a field including information about whether UHR-SIG is generated over the entire band, 6) a field including information about the type of UHR-LTF / STF, and 7) a field indicating the length of UHR-LTF and the CP length.

[0114] Preamble puncturing may be applied to the PPDU of FIG. 5. Preamble puncturing refers to applying puncturing to a portion of the entire bandwidth of the PPDU (e.g., the secondary 20 MHz band). For example, when an 80 MHz PPDU is transmitted, the STA applies puncturing to the secondary 20 MHz band within the 80 MHz band, and can transmit the PPDU only through the primary 20 MHz band and the secondary 40 MHz band.

[0115] For example, the pattern of preamble puncturing can be preset. For example, when the first puncturing pattern is applied, puncturing can be applied only to the secondary 20 MHz band within the 80 MHz band. For example, when the second puncturing pattern is applied, puncturing can be applied only to one of the two secondary 20 MHz bands included in the secondary 40 MHz band within the 80 MHz band. For example, when the third puncturing pattern is applied, puncturing can be applied only to the secondary 20 MHz band included in the primary 80 MHz band within the 160 MHz band (or 80+80 MHz band). For example, when the fourth puncturing pattern is applied, a primary 40 MHz band included in the primary 80 MHz band within the 160 MHz band (or 80+80 MHz band) may be present, and puncturing may be applied to at least one 20 MHz channel that does not belong to the primary 40 MHz band.

[0116] Information regarding preamble puncturing applied to the PPDU may be included in the U-SIG and / or UHR-SIG. For example, the first field of the U-SIG may include information regarding the contiguous bandwidth of the PPDU, and the second field of the U-SIG may include information regarding preamble puncturing applied to the PPDU.

[0117] For example, U-SIG and UHR-SIG may include information regarding preamble puncturing based on the following method. If the bandwidth of the PPDU exceeds 80 MHz, the U-SIG may be individually configured in units of 80 MHz. For example, if the bandwidth of the PPDU is 160 MHz, the PPDU may include a first U-SIG for the first 80 MHz band and a second U-SIG for the second 80 MHz band. In this case, the first field of the first U-SIG may include information regarding the 160 MHz bandwidth, and the second field of the first U-SIG may include information regarding preamble puncturing applied to the first 80 MHz band (i.e., information regarding the preamble puncturing pattern). Additionally, the first field of the second U-SIG may include information about a 160 MHz bandwidth, and the second field of the second U-SIG may include information about preamble puncturing applied to the second 80 MHz band (i.e., information about a preamble puncturing pattern). Meanwhile, the UHR-SIG consecutive to the first U-SIG may include information about preamble puncturing applied to the second 80 MHz band (i.e., information about a preamble puncturing pattern), and the UHR-SIG consecutive to the second U-SIG may include information about preamble puncturing applied to the first 80 MHz band (i.e., information about a preamble puncturing pattern).

[0118] Additionally or alternatively, U-SIG and UHR-SIG may include information regarding preamble puncturing based on the following methods. U-SIG may include information regarding preamble puncturing for all bands (i.e., information regarding preamble puncturing patterns). That is, UHR-SIG may not include information regarding preamble puncturing, and only U-SIG may include information regarding preamble puncturing (i.e., information regarding preamble puncturing patterns).

[0119] U-SIGs can be configured in 20 MHz units. For example, if an 80 MHz PPDU is configured, U-SIGs can be duplicated. That is, four identical U-SIGs can be included within an 80 MHz PPDU. PPDUs exceeding the 80 MHz bandwidth can contain different U-SIGs.

[0120] The UHR-SIG of FIG. 5 may include control information for a receiving STA. The UHR-SIG may be transmitted via at least one symbol, and each symbol may have a length of 4 us. Information regarding the number of symbols used for the UHR-SIG may be included in the U-SIG.

[0121] UHR-SIG provides additional signals to the U-SIG field to enable STAs to interpret / decode UHR PPDUs. The UHR-SIG field may contain U-SIG overflow bits that are common to all users. The UHR-SIG field also contains resource allocation information, allowing STAs to look up resources used in fields containing data fields / UHR-STF / UHR-LTF (i.e., UHR modulated fields of an UHR PPDU).

[0122] The frequency resources of the UHR-LTF, UHR-STF, and data fields illustrated in FIG. 5 can be determined based on RUs (resource units) defined by multiple subcarriers / tones. That is, the UHR-LTF, UHR-STF, and data fields of this specification can be transmitted / received through RUs (resource units) defined by multiple subcarriers / tones.

[0123] FIG. 6 is a diagram illustrating the layout of resource units (RUs) used for a 20 MHz PPDU. That is, the UHR-LTF, UHR-STF, and / or data fields included in the 20 MHz PPDU can be transmitted / received through at least one of the various RUs defined in FIG. 6.

[0124] As shown at the top of Fig. 6, 26 units (i.e., units corresponding to 26 tones) can be arranged. Six tones can be used as a guard band in the leftmost band of the 20 MHz band, and five tones can be used as a guard band in the rightmost band of the 20 MHz band. In addition, seven DC tones can be inserted in the center band, i.e., the DC band, and 26 units corresponding to 13 tones can exist on each side of the DC band. In addition, 26 units, 52 units, and 106 units can be allocated to other bands. Each unit can be allocated for a receiving station, i.e., a user.

[0125] Meanwhile, the RU arrangement of FIG. 6 is utilized not only in a situation for multiple users (MUs) but also in a situation for a single user (SU), in which case it is possible to use one 242-unit as shown at the bottom of FIG. 4, in which case three DC tones can be inserted.

[0126] In the example of Fig. 6, RUs of various sizes, such as 26-RU, 52-RU, 106-RU, and 242-RU, are proposed. Since the specific sizes of these RUs can be expanded or increased, the present embodiment is not limited to the specific size of each RU (i.e., the number of corresponding tones). In this specification, N-RU may be represented as N-tone RU, etc. For example, 26-RU may be represented as 26-tone RU.

[0127] Figure 7 is a diagram showing the layout of resource units (RUs) used for 40MHz PPDU.

[0128] As in the example of Fig. 6 where RUs of various sizes were used, the example of Fig. 7 can also use 26-RU, 52-RU, 106-RU, 242-RU, 484-RU, etc. In addition, 5 DC tones can be inserted at the center frequency, 12 tones can be used as a guard band in the leftmost band of the 40 MHz band, and 11 tones can be used as a guard band in the rightmost band of the 40 MHz band.

[0129] Additionally, as illustrated, 484 RUs may be used when used for a single user. Meanwhile, the specific number of RUs may be changed, as in the example of FIG. 6.

[0130] Figure 8 is a diagram illustrating the layout of resource units (RUs) used for an 80MHz PPDU. The layout of resource units (RUs) used in this specification may vary. For example, the layout of resource units (RUs) used in the 80MHz band may vary.

[0131] Figure 9 illustrates an operation according to UL-MU. As illustrated, a transmitting STA (e.g., AP) can acquire a TXOP (925) by performing channel access through contending (i.e., backoff operation) and transmit a trigger frame (930). That is, the transmitting STA (e.g., AP) can transmit a PPDU including a trigger frame (930). When a PPDU including a trigger frame is received, a TB (trigger-based) PPDU is transmitted after a delay of SIFS.

[0132] TB PPDUs (941, 942) are transmitted at the same time and can be transmitted from multiple STAs (e.g., User STAs) whose AIDs are indicated in the Trigger frame (930). The ACK frame (950) for the TB PPDU can be implemented in various forms. For example, the ACK frame (950) for the TB PPDU can be implemented in the form of a BA (block ACK).

[0133] In FIG. 9, transmission(s) of a Trigger Frame (930), TB PPDU (941, 942) and / or ACK frame (950) can be performed within a TXOP (925).

[0134] Figure 10 shows an example of channels used / supported / defined within the 2.4 GHz band.

[0135] The 2.4 GHz band may be referred to by other names, such as the first band (band). Furthermore, the 2.4 GHz band may refer to a frequency range in which channels with a center frequency adjacent to 2.4 GHz (e.g., channels with a center frequency between 2.4 and 2.5 GHz) are used / supported / defined.

[0136] The 2.4 GHz band may include multiple 20 MHz channels. The 20 MHz within the 2.4 GHz band may have multiple channel indices (e.g., indices 1 through 14). For example, the center frequency of a 20 MHz channel assigned channel index 1 may be 2.412 GHz, the center frequency of a 20 MHz channel assigned channel index 2 may be 2.417 GHz, and the center frequency of a 20 MHz channel assigned channel index N may be (2.407 + 0.005*N) GHz. The channel indices may be referred to by various names, such as channel numbers. The specific numerical values ​​of the channel indices and center frequencies may change.

[0137] Figure 10 exemplarily illustrates four channels within the 2.4 GHz band. The illustrated first frequency region (1010) to fourth frequency region (1040) may each include one channel. For example, the first frequency region (1010) may include channel 1 (a 20 MHz channel having an index of 1). In this case, the center frequency of channel 1 may be set to 2412 MHz. The second frequency region (1020) may include channel 6. In this case, the center frequency of channel 6 may be set to 2437 MHz. The third frequency region (1030) may include channel 11. In this case, the center frequency of channel 11 may be set to 2462 MHz. The fourth frequency region (1040) may include channel 14. In this case, the center frequency of channel 14 may be set to 2484 MHz.

[0138] Figure 11 illustrates an example of channels used / supported / defined within the 5 GHz band.

[0139] The 5 GHz band may be referred to by other names, such as a second band / band, etc. The 5 GHz band may refer to a frequency range in which channels with center frequencies greater than or equal to 5 GHz and less than 6 GHz (or less than 5.9 GHz) are used / supported / defined. Alternatively, the 5 GHz band may include multiple channels between 4.5 GHz and 5.5 GHz. The specific figures shown in FIG. 11 are subject to change.

[0140] Multiple channels within the 5 GHz band include Unlicensed National Information Infrastructure (UNII)-1, UNII-2, UNII-3, and ISM. UNII-1 may be referred to as UNII Low. UNII-2 may include frequency ranges called UNII Mid and UNII-2Extended. UNII-3 may be referred to as UNII-Upper.

[0141] Within the 5 GHz band, multiple channels can be configured, and the bandwidth of each channel can be variously configured, such as 20 MHz, 40 MHz, 80 MHz, or 160 MHz. For example, the 5170 MHz to 5330 MHz frequency domain / range within UNII-1 and UNII-2 can be divided into eight 20 MHz channels. The 5170 MHz to 5330 MHz frequency domain / range can be divided into four channels through a 40 MHz frequency domain. The 5170 MHz to 5330 MHz frequency domain / range can be divided into two channels through an 80 MHz frequency domain. Alternatively, the 5170 MHz to 5330 MHz frequency domain / range can be divided into one channel through a 160 MHz frequency domain.

[0142] Figure 12 illustrates an example of channels used / supported / defined within the 6 GHz band.

[0143] The 6 GHz band may also be referred to by other names, such as the third band / band. The 6 GHz band may refer to the frequency range in which channels with center frequencies above 5.9 GHz are used, supported, or defined. The specific figures shown in Figure 12 are subject to change.

[0144] For example, the 20 MHz channel of FIG. 12 can be defined from 5.940 GHz. Specifically, the leftmost channel among the 20 MHz channels of FIG. 12 can have an index of 1 (or channel index, channel number, etc.), and a center frequency of 5.945 GHz can be assigned. That is, the center frequency of the indexed channel N can be determined as (5.940 + 0.005*N) GHz.

[0145] Accordingly, the indexes (or channel numbers) of the 20 MHz channels of FIG. 12 are 1, 5, 9, 13, 17, 21, 25, 29, 33, 37, 41, 45, 49, 53, 57, 61, 65, 69, 73, 77, 81, 85, 89, 93, 97, 101, 105, 109, 113, 117, 121, 125, 129, 133, 137, 141, 145, 149, 153, 157, 161, 165, 169, 173, 177, 181, 185, 189, 193, It can be 197, 201, 205, 209, 213, 217, 221, 225, 229, 233. Also, according to the (5.940 + 0.005*N) GHz rule mentioned above, the indices of the 40 MHz channels in Fig. 12 can be 3, 11, 19, 27, 35, 43, 51, 59, 67, 75, 83, 91, 99, 107, 115, 123, 131, 139, 147, 155, 163, 171, 179, 187, 195, 203, 211, 219, 227.

[0146] Below, the structure and types / subtypes of MAC frames are described.

[0147] Fig. 13 illustrates an example of a header of a MAC frame. As illustrated, the MAC frame may include a frame control field / information of 2 octets in length, a duration field / information of 2 octets in length, a RA (Receiver Address) field / information of 6 octets in length, and a TA (Transmitter Address) field / information of 6 octets in length. As illustrated in Fig. 13, the four fields may be consecutive to each other. The MAC header of Fig. 13 may be modified in various ways, and a new field may be inserted between the four illustrated fields, or at least one of the illustrated fields may be omitted.

[0148] The MAC header illustrated in Fig. 13 may be positioned at the very front of a MAC frame. That is, the MAC frame may include a MAC header as illustrated in Fig. 13 and MAC body fields / information subsequent to the MAC header. The MAC frame including the MAC header of Fig. 13 is inserted / included in the data field of the PPDU (e.g., UHR PPDU) illustrated in Fig. 5.

[0149] The MAC frames included in the data field of the PPDU of this specification can be classified into various types. For example, the MAC frames of this specification can be classified into control frames, management frames, and data frames.

[0150] For example, the management frame includes Association Request, Association Response, Reassociation Request, Reassociation Response, Probe Request, Probe Response, Beacon, Disassociation, Authentication, and Deauthentication frames / signals defined in conventional WLAN. For the management frame, the values ​​of the type fields (B3 and B2) in FIG. 13 are set to 00. In addition, the values ​​of the subtype fields (B7, B6, B5, B4) in FIG. 13 are as follows: Association Request (0000), Association Response (0001), Reassociation Request (0010), Reassociation Response (0011), Probe Request (0100), Probe Response (0101), Beacon (1000), Disassociation (1010), Authentication (1011), Deauthentication (1100).

[0151] For example, the control frame includes Trigger Beamforming Report Poll, NDP Announcement (NDPA), Control Frame Extension, Control Wrapper, Block Ack Request (BlockAckReq), Block Ack (BlockAck), PS-Poll, RTS, CTS, Ack, and CF-End frames / signals defined in conventional WLAN. For the control frame, the value of the type field (B3 and B2) in FIG. 13 is set to 01. Also, the values ​​of the subtype fields (B7, B6, B5, B4) of FIG. 13 are as follows: Trigger (0010), Beamforming Report Poll (0100), NDP Announcement (0101), Control Frame Extension (0110), Control Wrapper (0111), BlockAckReq (1000), BlockAck (1001), PS-Poll (1010), RTS (1011), CTS (1100), Ack (1101), CF-End (1110).

[0152] For example, the data frame includes (QoS) Data, (QoS) Null, etc. defined in conventional WLAN. For the management frame, the value of the type field (B3 and B2) of Fig. 13 is set to 10.

[0153] The MAC frame / signal used in this specification can be identified through the type field / information and subtype field / information described above. For example, the "trigger frame" in this specification can mean a MAC frame in which the type bits B3 and B2 bits in the frame control field of the MAC header are set to 01, and the subtype bits B7, B6, B5, B4 bits in the frame control field are also set to 0010. Various MAC frames described in this specification are inserted / included in the data fields of various PPDUs (e.g., HE / VHT / HE / EHT / UHR PPDUs).

[0154] FIG. 14 illustrates a modified example of a transmitting device and / or a receiving device of the present specification.

[0155] The devices (e.g., AP STA, non-AP STA) illustrated in FIGS. 1 to 4 may be modified as illustrated in FIG. 14. The transceiver (630) of FIG. 14 may be identical to the transceivers (113, 123) of FIG. 1. The transceiver (630) of FIG. 14 may include a receiver and a transmitter.

[0156] The processor (610) of FIG. 14 may be identical to the processor (111, 121) of FIG. 1. Alternatively, the processor (610) of FIG. 14 may be identical to the processing chip (114, 124) of FIG. 1.

[0157] The memory (150) of FIG. 14 may be the same as the memory (112, 122) of FIG. 1. Alternatively, the memory (150) of FIG. 14 may be a separate external memory different from the memory (112, 122) of FIG. 1.

[0158] Referring to FIG. 14, a power management module (611) manages power to a processor (610) and / or a transceiver (630). A battery (612) supplies power to the power management module (611). A display (613) outputs results processed by the processor (610). A keypad (614) receives input to be used by the processor (610). The keypad (614) may be displayed on the display (613). A SIM card (615) may be an integrated circuit used to securely store an international mobile subscriber identity (IMSI) and an associated key used to identify and authenticate a subscriber in a mobile phone device, such as a mobile phone or computer.

[0159] Referring to FIG. 14, the speaker (640) can output sound-related results processed by the processor (610). The microphone (641) can receive sound-related input to be used by the processor (610).

[0160] Figure 15 illustrates an example of a network allocation vector (NAV) setting. The example in Figure 15 relates to the exchange of RTS (Ready To Send) frames and CTS (Clear To Send) frames. Figure 15 relates to an example in which a NAV is set based on an RTS / CTS exchange.

[0161] Referring to Figure 15, the Source STA transmits an RTS frame, and the Destination transmits a CTS frame. As described above, the destination STA designated as the receiver through the RTS frame does not set a NAV. Some of the remaining STAs may receive the RTS frame and set a NAV, and others may receive the CTS frame and set a NAV.

[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., 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.

[0163] In Fig. 15, for convenience, setting or updating NAV through RTS frame or CTS frame is illustrated, but NAV setting / resetting / updating can be performed based on a duration field (e.g., duration field in MAC header of MAC frame) included in one PPDU based on various other frames, for example, non-HT PPDU, HT PPDU, VHT PPDU, HE PPDU, EHT PPDU, and / or UHR PPDU. For example, if the RA field in the received MAC frame does not match its own address (e.g., MAC address), the STA can set / reset / update NAV.

[0164] The Source STA of FIG. 15 may be modified in various ways. For example, the Source STA of FIG. 15 may be a non-AP STA or an AP. Additionally or alternatively, the Source STA of FIG. 15 may be at least one non-AP STA included in a non-AP MLD, or at least one AP included in an AP MLD. Additionally or alternatively, the Source STA of FIG. 15 may be various STAs, such as STA 1, STA 2, AP 1, and AP 2, as described below.

[0165] Below, primary channels, secondary channels, channel extension / bonding, etc. are explained.

[0166] For example, in an IEEE 802.11n system, two 20MHz channels can be combined to perform 40MHz channel extension / bonding. Additionally, in an IEEE 802.11ac system, 40 / 80 / 160MHz channel extension / bonding can be performed.

[0167] For example, an STA can perform channel extension / bonding for a Primary 20 MHz channel (or P20 channel) and a Secondary 20 MHz channel (S20 channel). For channel extension / bonding, a backoff count / counter can be used. The backoff count value can be randomly selected and decremented during the backoff interval. Typically, when the backoff count value becomes 0, an STA (e.g., a non-AP STA or AP) can attempt to connect to the channel.

[0168] An STA performing channel extension / bonding determines whether the S20 channel has been in the Idle state for a certain period of time (e.g., point coordination function interframe space (PIFS)) when the P20 channel is determined to be in the Idle state during the backoff interval and the backoff count value for the P20 channel becomes 0. If the S20 channel is in the Idle state, the STA can perform bonding for the P20 channel and the S20 channel. That is, the STA can transmit a signal (e.g., PPDU) through a 40 MHz channel including the P20 channel and the S20 channel (i.e., a 40 MHz bonding channel).

[0169] Figure 16 illustrates an example related to a primary channel, a secondary channel, and channel extension / bonding. As illustrated in Figure 16, a primary 20 MHz channel and a secondary 20 MHz channel can form a 40 MHz channel (primary 40 MHz channel) through channel extension / bonding. That is, an extended / bonded 40 MHz channel can include a primary 20 MHz channel and a secondary 20 MHz channel.

[0170] The positions of the channels (e.g., P20 / S20 / S40 / S80 channels) shown in Fig. 16 can be varied in the frequency domain.

[0171] According to the prior art, channel expansion / bonding can be performed when a channel consecutive to a primary channel is in an idle state. That is, a primary 20 MHz channel (or P20 channel), a secondary 20 MHz channel (or S20 channel), a secondary 40 MHz channel (or S40 channel), and a secondary 80 MHz channel (or S40 channel) can be sequentially expanded / bonded. However, if the secondary 20 MHz channel (or S20 channel) is determined to be busy, channel expansion / bonding may not be performed even if all other secondary channels are in an idle state. In addition, if the secondary 20 MHz channel (or S20 channel) is determined to be idle and the secondary 40 MHz channel is determined to be busy, channel expansion / bonding can be performed only for the primary 20 MHz channel (or P20 channel) and the secondary 20 MHz channel (or S20 channel).

[0172] For example, in a wireless LAN system (e.g., 802.11 system), Channel Access can be performed based on the Primary channel (e.g., P20 channel). For example, as described above, an STA can transmit a frame (e.g., 40 MHz PPDU) including an IDLE Secondary channel (e.g., S20 channel) when the Primary channel (e.g., P20 channel) is IDLE and the Back-off counter (BC) is 0. For this purpose, it is desirable for all STAs to perform CCA on the Primary channel (e.g., P20 channel).

[0173] Therefore, the AP can announce the BSS's Primary channel (e.g., P20 channel). For example, information related to the Primary channel can always be included in Management frames transmitted by the AP, such as Beacon and Probe Response frames. This mechanism is effective for ensuring interference-free frame exchange between all STAs and the AP (or for adequate medium protection). However, if only the primary channel (e.g., P20 channel) is BUSY and the surrounding secondary channels are IDLE, the STA can access the IDLE secondary channel. Consequently, there is a technical characteristic that may reduce efficiency from a medium utilization perspective.

[0174] Figure 17 relates to an example of channel access related to an 80 MHz channel. For example, Figure 17 relates to channel access based on a primary channel defined on a wireless medium having an 80 MHz bandwidth. The three channels / subchannels illustrated in Figure 17 are denoted as P20, S20, S40, etc., and the related terminology can be explained as follows.

[0175] P20: Primary 20MHz Channel

[0176] S20: Secondary 20MHz Channel

[0177] S40: Secondary 40MHz Channel

[0178] S80: Secondary 80MHz Channel

[0179] S160: Secondary 160MHz Channel

[0180] The above-described P20, S20, S40, S80, and S160 can correspond to each channel / subchannel shown in Fig. 16.

[0181] For example, if the CCA result for P20 (channel) is determined to be BUSY, or if NAV (as described in FIG. 15) is set for P20 and determined to be BUSY, the BC for P20 is not decreased. In this case, the BC may not be decreased until P20 becomes IDLE. When the BC becomes 0 through this back-off process (e.g., BC decrease process), the STA can check the channel states of S20 (channel) and S40 (channel) (e.g., check based on the CCA technique). In addition, the STA can transmit a frame through the extended channel / resource according to the check result. In the example of FIG. 17, since S40 (channel) is BUSY, a frame corresponding to a 40MHz PPDU is transmitted through P20 and S20. In other words, the example of FIG. 17 relates to an example in which a 40 MHz channel including a P20 channel and an S20 channel is configured through the channel expansion / bonding described above.

[0182] As in the example of Fig. 17, when P20 is determined to be BUSY and S20 and S40 are determined to be IDLE, an STA operating according to a conventional access technique wastes a bandwidth equivalent to 60 MHz. Consequently, the efficiency of medium usage decreases. The example of this specification proposes various techniques / methods / devices to improve this. For example, the example of this specification proposes various techniques / methods / devices that enable access to a secondary channel (or non-primary channel) even when P20 is BUSY.

[0183] The various examples below are preferably applied to STAs of a wireless LAN system. For example, the STAs (or STA1 to STA#N, etc.) below may be at least one non-AP STA (included in a non-AP MLD) or at least one AP (included in an AP MLD).

[0184] This specification relates to an operation for performing Access to a Secondary Channel (e.g., S20). Access to a Secondary Channel may be expressed as Secondary Channel Access (SCA). When an SCA is initiated / performed / triggered, an STA may switch to a Secondary Channel (e.g., S20) and subsequently perform CCA sensing (and / or backoff counter decrement) on the switched Secondary Channel.

[0185] The term "SCA" can be variously modified. For example, "SCA" can have the same meaning as "Non-Primary Channel Access" (NPCA). For example, in the examples below, the term "SCA" can be replaced with the term "NPCA." For example, in the examples below, the term "SCA mode" can be replaced with the term "NPCA mode." Furthermore, in the examples below, the term "SCA enabled presence" can be replaced with the term "NPCA enabled presence."

[0186] Additionally or alternatively, the term "Secondary Channel" may be variously modified. For example, the secondary 20MHz channel described above may also be called the NPCA primary channel (or NPCH), since the primary operations related to SCA / NPCA are performed by STAs (e.g., by APs / non-AP STAs).

[0187] Below is information related to Capabilities for Secondary Channel Access.

[0188] For example, Capabilities for SCA (or NPCA) can be defined / exchanged / negotiated in advance. For example, non-AP STAs and APs can inform each other of the defined / exchanged / negotiated information. For example, Capabilities for SCA (or NPCA) can be related to CCA (e.g., an operation based on conventional preamble detection (PD)) that can identify Wi-Fi frames performed on a primary channel (e.g., the P20 channel described above). For example, as in the specific example below, Capabilities for SCA (or NPCA) can include information on whether frames can be decoded on the SCH (or the S20 channel or the NPCA primary channel or the NPCH). Through these Capabilities for SCA / NPCA, additional NAV(s) (e.g., at least one Intra-BSS NAV and / or Basic NAV) can be set on the SCH (or the NPCA primary channel or the NPCH).

[0189] For example, Capabilities for SCA (or NPCA) can be configured based on 2-bit information. For example, Level 0 / 1 / 2 as shown below can be identified through the first / second / third values ​​of the 2-bit information. The length of the 2-bit information can be varied. Accordingly, the 2-bit information can also be configured through 3 / 4 / 5 bits, etc. Not all of Level 0 / 1 / 2 below must be used, and at least one can be selectively used.

[0190] The three specific levels of Capabilities for the above-mentioned SCA (or NPCA) are explained below.

[0191] Level 0: For example, Level 0 may mean "No Back-off on SCH." For example, when the level is set, CCA as before may be performed on the SCH (by the STA). In this case, CCA capable of detecting a Wi-Fi signal (e.g., referred to as guard interval detection (GID)) and / or CCA capable of detecting a signal above a certain strength (e.g., referred to as energy detection (ED)) may be performed.

[0192] Level 1: For example, Level 1 may mean "Back-off on a SCH at a time." For example, when this level is set, PD can only be performed on one secondary channel at a time.

[0193] Level 2: For example, Level 2 may mean "Back-off on SCHs at the same time." For example, when this level is set, PD can be performed on multiple secondary channels simultaneously.

[0194] For example, the Capabilities described above may be included in various management frames, such as Beacon, Probe Response frame, (Re)Association Request frame, etc., generated / transmitted by the AP, including UHR capabilities IE, etc. Additionally or alternatively, the Capabilities described above may be included in various management frames, such as Probe Request frame, (Re)Association Request frame, etc., generated / transmitted by non-AP STAs.

[0195] The NAV described in Fig. 15 can be distinguished into Intra-BSS NAV and Basic NAV. Intra-BSS NAV may be a NAV set by Intra-BSS frame / PPDU, and Basic NAV may be a NAV set by OBSS (overlapping BSS) frame / PPDU.

[0196] For example, if an Intra-BSS NAV is set for the PCH by an STA (e.g., a non-AP STA or an AP), SCA (or NPCA) may not be performed. For example, when an AP exchanges frames with an STA (e.g., a non-AP STA) within the TXOP it acquired, the other STA may set an intra-BSS NAV based on the primary channel. At this time, the STA that set the intra-BSS NAV can transmit the frame to the AP after accessing the SCH, and in this case, if the AP is performing Tx (e.g., DL Data, Ack, etc.), the AP will not receive the related signal. Accordingly, it is desirable for the STA to initiate / trigger SCA only when the Basic NAV is set on the PCH.

[0197] The above technical characteristic can be expressed in various ways. For example, the above technical characteristic can be expressed as: an STA (e.g., a non-AP STA or AP) can perform SCA when Basic NAV is configured on the PCH.

[0198] Figure 18 illustrates an example of an SCA process. The example of Figure 18 (e.g., SCA / NPCA operation) can be performed by STA1 (e.g., an AP or a non-AP STA). As illustrated, if a Basic NAV is set while performing a back-off on the P20 channel, the back-off can be performed on the S20 channel (or NPCA primary channel or NPCH) at the time the Basic NAV is set. In this case, the back-off on the S20 channel (or NPCA primary channel) may be performed after a delay from the time the Basic NAV is set, rather than immediately after the time the Basic NAV is set. For example, a switching delay may occur to perform PD from the P20 channel to the S20 channel. The above example differs from the CCA method in that CCA can be performed on the S20 channel, and can be performed at all levels. The reason why back-off is performed on the S20 channel (or NPCA primary channel) is that if a neighboring STA with the same or similar operation channel as STA 1 does not perform back-off and is IDLE, frames can be transmitted simultaneously. In this case, a collision may occur, which may result in channel waste.

[0199] SCA / NPCA can be performed based on the following technical features:

[0200] First, an example of transmitting a Frame on a secondary channel (e.g., at least one channel including an NPCA primary channel (or NPCH)) is described.

[0201] Previously, the P20 channel had to be determined to be IDLE, and then preamble puncturing could be performed based on the IDLE / BUSY determination of at least one SCH channel. For the SCA / NPCA of this specification, since the P20 channel is considered to be BUSY, the rule for this can be changed as follows. For example, if the P20 channel is determined to be BUSY, the P20 channel can be punctured, and other BUSY SCH(s) based on the S20 channel can also be punctured, and as a result, a frame can be transmitted through the IDLE SCH(s). For example, in the example of FIG. 18, all three 20MHz channels included in the S20 and S40 channels are determined to be IDLE. Accordingly, STA1 can transmit an 80MHz PPDU (including a MAC frame) while performing preamble puncturing on the P20 channel of the 80MHz PPDU. That is, the U-SIG field of the 80 MHz PPDU may include information indicating puncturing of the P20 channel.

[0202] Second, here is an example of setting TXOP on the secondary channel (or NPCA primary channel or NPCH):

[0203] For example, when the Basic NAV on the P20 channel expires, a CCA may need to be performed on the P20 channel. Accordingly, it is desirable that the end time of the TXOP for the secondary channel (e.g., the S20 channel or the NPCA primary channel or NPCH) be set to end before the time when the Basic NAV on the primary channel (e.g., the P20 channel) expires.

[0204] Additionally or alternatively, if there is not enough time to set up the TXOP of the secondary channel, the Frame may not be transmitted (on the secondary channel).

[0205] For example, if the end time of the TXOP of the secondary channel is set to end after the time when the Basic NAV (of the primary channel) expires, a problem may occur in which STA1 of FIG. 18 cannot receive the frame because Legacy STAs, etc. may transmit the frame through the P20 channel. In addition, if the TBTT is set in the middle of the Basic NAV, a problem may occur because STA1 of FIG. 18 must prepare to transmit the Beacon immediately after the Basic NAV.

[0206] To efficiently perform SCA / NPCA, the technical characteristics described above must be further improved. For example, it is desirable to optimize the timing of SCA / NPCA execution, or the timing of switching to the SCH (or NPCA primary channel, or NPCH) for SCA / NPCA execution.

[0207] For example, initiating a switch to the SCH (or NPCA primary channel or NPCH l) to perform SCA / NPCA may involve triggering the SCA / NPCA (action). For example, triggering the SCA / NPCA (action) may mean switching to the SCH (or NPCA primary channel) or accessing that channel. Additionally or alternatively, triggering the SCA / NPCA (action) may mean determining whether to switch to the SCH (or NPCA primary channel) (or whether to access that channel). Additionally or alternatively, triggering the SCA / NPCA (action) may mean switching to the SCH (or NPCA primary channel) after acquiring control information for switching to the SCH (or NPCA primary channel) (e.g., acquiring information about an OBSS PPDU). For example, switching to the SCH (or NPCA primary channel) may mean performing a procedure prior to receiving a signal (e.g., CCA / ED / PD) on the SCH (or NPCA primary channel) after completing an operation on the PCH.

[0208] This specification describes various triggering conditions for SCA / NPCA (operations). If the various triggering conditions proposed in this specification are satisfied, the corresponding STA (e.g., AP or non-AP STA) can initiate / attempt switching to the above-described SCH (or NPCA primary channel or NPCH). If the various triggering conditions proposed in this specification are not satisfied, the corresponding STA (e.g., AP or non-AP STA) cannot initiate / attempt switching to the above-described SCH (or NPCA primary channel).

[0209] The NPCA triggering condition proposed in this specification can be determined based on 1) the version (or type) of the OBSS PPDU (or received traffic) received by the STA and / or 2) a predefined or negotiated rule. For example, the NPCA triggering condition may vary depending on which version (or type) of OBSS PPDU is received by the STA. Additionally or alternatively, the NPCA triggering condition may vary based on a predefined or negotiated rule.

[0210] The aforementioned NPCA triggering conditions (e.g., conditions / timing for switching to NPCA-related channels, conditions / timing for accessing those channels) should be optimized to take into account various circumstances. Improving NPCA triggering conditions can impact NPCA / SCA performance as follows:

[0211] For example, for higher performance of NPCA / SCA, it is desirable for an STA performing NPCA / SCA to switch to the NPCA primary channel (e.g., S20 channel or NPCH) as soon as possible after acquiring information to perform NPCA / SCA. Additionally or alternatively, it is desirable for multiple SCAs to switch to the NPCA primary channel (e.g., S20 channel) as simultaneously as possible. For example, if the switch is performed / initiated quickly, an STA performing NPCA / SCA can acquire / set a longer TXOP on the NPCA primary channel (e.g., S20 channel). Additionally, if the switch is performed / initiated as close or at the same time as possible, unnecessary FE (Frame Exchange) initiating on the NPCA primary channel (e.g., S20 channel) can be prevented.

[0212] In other words, improving the NPCA triggering conditions (e.g., the timing / action of switching to the NPCA primary channel (e.g., S20 channel or NPCH), or the start / action of accessing that channel) can result in various technical effects.

[0213] For example, when to switch to the NPCA primary channel (e.g., S20 channel or NPCH) or when to trigger NPCA can be defined differently depending on the version / type of the PPDU (e.g., OBSS PPDU). For example, in order to perform NPCA / SCA, at least one STA (e.g., AP or non-AP STA) can 1) determine whether the received traffic is an OBSS PPDU or an intra-BSS PPDU, and 2) obtain information on how long to perform NPCA / SCA (e.g., TXOP information or PPDU Length information). Additionally or alternatively, the STA can 3) determine whether the SCH on which backoff is performed (e.g., NPCA primary channel or NPCH or S20 channel) overlaps with OBSS traffic (e.g., OBSS PPDU received on the PCH). For example, if the channel / subchannel / frequency resource on which the OBSS traffic is received overlaps with the SCH (or NPCH, S20 channel, etc.), it may not make sense for the STA to switch to the corresponding SCH and perform SCA (or NPCA). For example, the time at which the above-described information can be acquired may vary depending on the PPDU version / type (Non-HT, HT, VHT, HE, EHT, or UHR PPDU). In addition, for example, initiating / performing the switch (or triggering NPCA) at the earliest time (and as close or at the same time as possible) after acquiring the above-described information may affect the performance of NPCA / SCA.

[0214] For example, an STA (e.g., an AP) can announce information about whether information required for NPCA / SCA is provided based on a) the PHY Header (e.g., the PHY preamble included in the OBSS PPDU), and b) whether information for NPCA / SCA is provided based on the MAC Header (e.g., the MAC Header included in the OBSS PPDU). Additionally or alternatively, the STA can announce information about whether the duration for performing NPCA / SCA is set based on the TXOP or the PPDU Length. Additionally or alternatively, the STA can announce information about a threshold value (e.g., TXOP Duration Threshold or PPDU Length Threshold) for performing NPCA / SCA to obtain a TXOP, because performing NPCA / SCA does not allow sufficient FE (Frame Exchange) if the TXOP or PPDU length is too short. For example, the STA (e.g., AP) may include at least one of the information elements (IEs) described below for NPCA / SCA operation. The information element (UE) may be included in the Management frame including the STA's Beacon and Probe Response within the UHR Operation IE or in the form of a new IE.

[0215] Below are examples of various information elements.

[0216] First Information Element (IE): PHY / MAC based NPCA

[0217] The above first information element (IE) may be information that indicates whether to acquire information required for NPCA / SCA based on a PHY Header (e.g., PHY preamble of a PPDU received on a PCH) and switch to an SCH channel based on the acquired information, or to switch to an SCH channel based on information obtained from a MAC Header (e.g., MAC header of a MAC frame included in a Data field of a PPDU received on a PCH).

[0218] For example, if the first information element (IE) has a length of 1 bit, when it is set to the first value (or value 0), information required for NPCA / SCA can be obtained based on the PHY Header, and when it is set to the second value (or value 1), information required for NPCA / SCA can be obtained based on the MAC Header. For example, the first information element (IE) can have various bit lengths. For example, when the first information element (IE) has the third value (or value 2), information required for NPCA / SCA can be obtained based on both the PHY and MAC headers.

[0219] For example, if the information required for NPCA / SCA is obtained based on the PHY Header, there is an advantage in that NPCA / SCA can be performed at a faster time, thereby securing a longer TXOP on the SCH. On the other hand, considering that the information required for NPCA / SCA may not be sufficient in the PHY Header depending on the PPDU type, if the information required for NPCA / SCA is obtained based on the MAC Header, there is an advantage in that NPCA / SCA can be performed for more OBSS PPDU types.

[0220] For example, when the first information element (IE) is set to the third value (e.g., when PHY / MAC based NPCA is set to 2), the time at which information required for NPCA / SCA can be obtained may vary depending on the PPDU format of the OBSS traffic. Specifically, the time at which information required for NPCA / SCA can be obtained may be determined together with the second information element (e.g., TXOP / PPDU based NPCA field) described below. For example, when the second information element (e.g., TXOP / PPDU based NPCA field) is the first value (e.g., 0) (e.g., when TXOP based), NPCA / SCA may be performed after TXOP information is obtained from the MAC header for non-HT / HT / VHT OBSS PPDU, and NPCA / SCA may be performed after TXOP information is obtained from the PHY header for HE / EHT / UHR OBSS PPDU. For example, if the second information element (e.g., TXOP based NPCA field) is the second value (e.g., 1) (e.g., based on PPDU Length), for non-HT / HT OBSS PPDU, NPCA / SCA is performed after checking the RA / TA address that can determine whether it is an OBSS PPDU from the MAC header. In this case, for VHT / HE / EHT / UHR OBSS PPDU, it is possible to determine whether it is an OBSS PPDU based on the BSS color of the PHY header and then perform NPCA / SCA.

[0221] Second Information Element (IE): TXOP / PPDU based NPCA

[0222] For example, the second information element (IE) may indicate whether the duration for performing NPCA / SCA is set based on the TXOP value or based on the PPDU Length value.

[0223] For example, if the second information element (IE) has a length of 1 bit, when the information element is set to a first value (eg, 0), the NPCA / SCA duration may be set based on the TXOP value, and when the information element is set to a second value (eg, 1), the NPCA / SCA duration may be set based on the PPDU Length value.

[0224] For example, when TXOP based NPCA is set, when performing NPCA / SCA, the TXOP value is generally longer than the PPDU Length, so there is an advantage that the duration for performing NPCA / SCA is longer.

[0225] For example, when PPDU Length NPCA is set, there is an advantage that when returning from SCH (e.g., S20 channel) to PCH (e.g., P20 channel) after performing NPCA / SCA, there is no issue of medium synchronization loss in PCH.

[0226] Third Information Element (IE): TXOP Duration Threshold

[0227] For example, the third information element (IE) may include information about the minimum TXOP duration that must be guaranteed when the value of the second information element (eg, TXOP / PPDU based NPCA) described above is the first value (eg, 0) (eg, when performing NPCA / SCA based on TXOP value). That is, when the TXOP value (eg, Basic NAV value) of the OBSS PPDU is smaller than the value set by the third information element, NPCA / SCA may not be performed even if the PCH (eg, P20 channel) is BUSY.

[0228] For example, the unit of the third information element can be expressed in ms. Additionally or alternatively, if the third information element has a length of 8 bits, for example, a value of 0000 0011 can indicate that the TXOP Duration Threshold is set to 3 ms. In this case, based on the third information element, the STA can perform NPCA / SCA only if the Basic NAV (value) is longer than 3 ms. Additionally or alternatively, the unit of the field can be us and the bit length can also be changed in various ways.

[0229] Information Element 4 (IE): PPDU Length Threshold:

[0230] For example, the fourth information element (IE) may include information about the minimum TXOP duration that must be guaranteed when the second information element (e.g., TXOP / PPDU based NPCA) described above is related to the PPDU Length value. For example, if the Length value of the OBSS PPDU is smaller than the value of the fourth information element, the STA may not perform NPCA / SCA even if the PCH (e.g., P20 channel) is determined to be BUSY. For example, the Length value of the PPDU can be identified / obtained through the LENGTH field of the L-SIG field of the PPDU.

[0231] For example, the unit of the fourth information element can be expressed in ms. Additionally or alternatively, if the fourth information element has a length of 8 bits, for example, a value of 0000 0011 can indicate that the PPDU Length Threshold is set to 3 ms. In this case, based on the fourth information element, the STA can perform NPCA / SCA only if the Length of the OBSS PPDU is longer than 3 ms. Additionally or alternatively, the unit of the corresponding field can be us and the bit length can also be changed in various ways.

[0232] At least one of the first to fourth information elements described above is related to a condition for triggering NPCA (or a condition for switching / accessing the NPCA primary channel (or NPCH)). In other words, in order for NPCA to be triggered (or to perform a switch / access to the NPCA primary channel), a condition related to at least one of the first to fourth information elements must be satisfied (e.g., a condition that the OBSS PPDU length is greater than the fourth information element is satisfied or a condition that the TXOP value of the OBSS PPDU is greater than the third information element is satisfied).

[0233] As for the condition for NPCA trigger (or the condition for switching / accessing the NPCA primary channel (or NPCH)), it can be based on the Version / type of the PPDU as described above. For example, the Version / type of the PPDU can be one of a non-HT (non-High Throughput) PPDU (Physical Protocol Data Unit), HT (High Throughput) PPDU, VHT (Very High Throughput) PPDU, HE (High Efficiency) PPDU, EHT (Extremely High Throughput) PPDU, and UHR (Ultra High Reliability) PPDU. Additionally or alternatively, the Version / type of the PPDU can be related to whether the PPDU contains RTS or MU-RTS. Additionally or alternatively, the Version / type of the PPDU can be related to whether the PPDU is a non-HT PPDU containing RTS or MU-RTS.

[0234] Specific technical characteristics related to the PPDU Version / type are as follows.

[0235] Version 1 / Type PPDU (e.g., RTS in Non-HT PPDU)

[0236] For example, if a PPDU (e.g., OBSS PPDU received on PCH) received by an STA (e.g., AP or non-AP STA) is a non-HT PPDU containing RTS or MU-RTS, the following may be considered.

[0237] In other words, the first version / type PPDU may be a PPDU including RTS or MU-RTS (e.g., Non-HT PPDU or Non-HT Duplicate PPDU). When the first version / type PPDU is received on the PCH, the condition for NPCA triggering (or the condition for switching / accessing the NPCA primary channel (or NPCH)) is determined by considering the following.

[0238] The PHY header of the non-HT PPDU may not contain sufficient information for NPCA / SCA. Accordingly, duration information for performing NPCA / SCA and information on whether it is OBSS traffic can be obtained through the MAC header of the non-HT PPDU.

[0239] In a conventional wireless LAN system, if a NAV is set due to RTS or MU-RTS, and a PPDU detection (e.g., detection of PHY-RXEARLYSIG.indication or PHY-RXSTART.indication primitive) is not received for a specific time (hereinafter referred to as NAVWaitTime or "NAV wait time"), the NAV set due to the RTS or MU-RTS can be reset (e.g., set to 0). The above-described NAVWaitTime can be calculated as (2 Х aSIFSTime) + (CTS_Time) + aRxPHYStartDelay + (2 Х aSlotTime), and the CTS_Time can be calculated according to the length of the CTS frame and the PHY data rate. The aSIFSTime, CTS_Time, aRxPHYStartDelay, and aSlotTime described above are parameter values ​​widely known in wireless LAN technology, and aSIFSTime can have a value corresponding to the length of SIFS (Short IFS), and CTS_Time can have a value corresponding to the length of the CTS frame corresponding to RTS / MU-RTS. In addition, for example, aRxPHYStartDelay is an integer delay value determined according to the related PPDU version, and each delay, in microseconds, can be the delay time from the start of the PPDU at the receiver's antenna to the issuance of the earlier of the PHYRXEARLYSIG.indication if sent or the PHY-RXSTART.indication primitive.Also, for example, aSlotTime can be the slot time in microseconds used by the MAC layer of the wireless LAN device to define the IFS.

[0240] For example, for an STA (e.g., non-AP / AP) that performs NPCA / SCA by switching to SCH (e.g., S20 channel or NPCA primary channel or NPCH) due to an RTS (or MU-RTS) received from an OBSS (e.g., OBSS PPDU on PCH), the following issues may occur when the NAV set by the RTS (or MU-RTS) is reset. For example, the NAV should be reset when: a) a related CTS is not received due to a failure in RTS transmission (or MU-RTS transmission), or b) the RTS transmission (or MU-RTS transmission) is successful, but transmission / reception of the CTS corresponding to the RTS fails.

[0241] The following issues may arise in the situation described above:

[0242] When Basic NAV is set due to RTS or MU-RTS on OBSS (e.g., OBSS PPDU on PCH), but PPDU detection (e.g., detection of PHY-RXEARLYSIG.indication or PHY-RXSTART.indication primitive) is not performed for a certain period of time (e.g., NAVWaitTime described above), the Basic NAV should be reset (e.g., set to 0). However, an STA (e.g., AP / non-AP) that has set the Basic NAV may not be aware of the reset of the Basic NAV since it has already switched to the SCH. Due to this, an issue of losing medium synchronization may exist when an STA (e.g., AP and non-AP) performing NPCA / SCA returns to the PCH. Additionally, for example, a legacy STA that has reset the Basic NAV (e.g., a legacy STA prior to 11bn or a legacy STA prior to UHR) may transmit frames based on the PCH, so there may be an issue in which frame collision occurs.

[0243] To solve the above issue, the STA of the present specification can perform the following operations. For example, when the STA (e.g., AP / non-AP) sets the Basic NAV due to RTS (or MU-RTS) (received on the PCH), it is preferable not to perform NPCA / SCA by switching to the SCH immediately after the Basic NAV is set. In other words, the NPCA may not be triggered immediately after the Basic NAV is set. Instead, the STA of the present specification can wait for the maximum NAVWaitTime (e.g., wait for the maximum NAVWaitTime from the time the Basic NAV is set). If PPDU detection occurs during the NAVWaitTime (e.g., when a Data frame is detected on the PCH or a CTS frame is detected on the PCH), the STA may determine that a non-reset Basic NAV is set and switch to the SCH (or trigger access to the SCH or NPCA).

[0244] Additionally or alternatively, if the STA does not detect any PPDU (on the PCH) while waiting for the maximum NAVWaitTime, the STA may reset the Basic NAV in the PCH (e.g., set to 0) and perform a back-off procedure in the PCH without switching to the SCH.

[0245] Figure 19 is an example of a network topology related to an example of this specification.

[0246] As illustrated in FIG. 19, when Non-AP STA 1-1 transmits RTS to AP 1, Non-AP STA 2-1, Non-AP STA 2-2, and AP2, which can overhear the frame of Non-AP STA 1-1, can set Basic NAV due to RTS. In this case, the STA that has set Basic NAV may not immediately switch to SCH but may wait during the NAVWaitTime. For example, if PPDU detection is confirmed during the NAVWaitTime, the Basic NAV will not be reset, and the STA can switch to SCH.

[0247] Referring to Figure 19, the technical features applicable to individual STAs are explained by dividing them into Case 1 and Case 2.

[0248] Case 1:

[0249] The operation of an STA (e.g., AP / non-AP) based on Case 1 may be as follows.

[0250] For example, the following are cases in which an OBSS PPDU can be received and immediately switched to the SCH. For example, Non-AP STA 2-1, Non-AP STA 2-2, and AP 2 can receive the RTS transmitted by Non-AP STA 1-1 and immediately switch to the SCH to perform NPCA / SCA. This case has the advantage that the STAs performing NPCA / SCA can hold the TXOP on the SCH for a longer period of time. Additionally or alternatively, the OBSS PPDU can be an RTS or MU-RTS.

[0251] In other words, an STA operating based on Case 1 receives an OBSS PPDU received on the PCH, and if the OBSS PPDU includes RTS (or MU-RTS), sets Basic NAV for the PCH, and immediately performs a switch to the NPCA primary channel (or NPCH) (or immediately performs an NPCA trigger) when the Basic NAV starts.

[0252] Case 2:

[0253] Case 2 is described below. The technical features of Case 2 are described based on Case 2-1 and Case 2. An STA operating based on Case 2 does not immediately switch to the SCH after the Basic NAV is set, but waits for a certain period of time to detect a PPDU on the PCH. If PPDU detection is confirmed on the PCT during the wait, the STA can switch to the SCH and perform NPCA / SCA based on the confirmation of the PPDU detection.

[0254] Case 2-1:

[0255] Fig. 20 illustrates an example related to Case 2-1. For example, an STA (e.g., non-AP STA 2-1 in Fig. 20) can receive a response frame for an OBSS PPDU (e.g., CTS from AP 1 to Non-AP STA 1-1 in Fig. 20). The STA can switch to the SCH based on the corresponding response received on the PCH. For example, Non-AP STA 2-1 in Fig. 20 is within the overhearing range for the PPDU transmitted by AP 1, so that when AP 1 transmits a response to the OBSS PPDU within the NAVWaitTime, Non-AP STA 2-1 can detect it. For example, if PPDU detection is determined, Non-AP STA 2-1 can switch to the SCH. Additionally or alternatively, the response frame for the OBSS PPDU can be a CTS.

[0256] Another way to express an example of FIG. 20 is as follows. An STA (e.g., Non-AP STA 2-1) can receive an OBSS PPDU through a primary channel (e.g., P20 channel). For example, the OBSS PPDU can include an RTS (or MU-RTS). If the received OBSS PPDU includes an RTS (or MU-RTS), a) the STA sets a Basic NAV for the primary channel, b) may not immediately perform a switch to the NPCA primary channel (or NPCH) (or immediately perform an NPCA trigger) when the Basic NAV starts, and c) may defer a switch to the SCH (or an NPCA trigger) by the NAVWaitTime described above. For example, if PPDU detection (e.g., CTS) is confirmed during the NAVWaitTime, the STA can immediately perform a switch to the NPCA primary channel (or immediately perform an NPCA trigger) at the time when PPDU detection is confirmed, even during the NAVWaitTime.

[0257] Case 2-2:

[0258] The above-described Case 2-1 is an example of performing a switch to the NPCA primary channel (or NPCH) (or performing an NPCA trigger immediately) when a response frame (e.g., CTS) for an OBSS PPDU is confirmed, but Case 2-2 relates to an example of performing a switch to the NPCA primary channel (or performing an NPCA trigger immediately) when a frame (e.g., Data frame) received after the response frame is confirmed.

[0259] For example, AP 2 and Non-AP STA 2-2 in FIG. 19 may not receive a response to an OBSS PPDU transmitted by AP1. In this case, AP 2 and Non-AP STA 2-2 may detect and switch to the SCH if Non-AP STA 1-1 transmits a frame following the response frame to the OBSS PPDU within the NAVWaitTime. Additionally or alternatively, the frame following the response frame to the OBSS PPDU may be a data frame.

[0260] The above Case 2-2 can be expressed differently as follows.

[0261] An STA (e.g., AP2 or Non-AP STA 2-2) can receive an OBSS PPDU through a primary channel (e.g., P20 channel). For example, the OBSS PPDU may include an RTS (or MU-RTS). If the received OBSS PPDU includes an RTS (or MU-RTS), a) the STA may set a Basic NAV for the primary channel, b) may not immediately perform a switch to an NPCA primary channel (or NPCH) (or immediately perform an NPCA trigger) when the Basic NAV starts, and c) may defer a switch to an SCH (or an NPCA trigger) by the NAVWaitTime described above. For example, even if the STA does not receive the response frame (e.g., CTS) of the OBSS during the NAVWaitTime, if a frame (e.g., Data frame related to RTS) following the response frame of the OBSS is confirmed, the STA can immediately perform a switch to the NPCA primary channel (or immediately perform an NPCA trigger) at the time when the frame (e.g., Data frame related to RTS) is confirmed, even during the NAVWaitTime.

[0262] Case 2, including Case 2-1 and Case 2-2 described above, can perform a switch to the SCH (e.g., the S20 channel or the NPCA primary channel or NPCH illustrated in FIG. 20) after confirming that the Basic NAV set in the PCH is not reset. This has the advantage that the STA does not lose medium synchronization in the PCH when returning to the PCH after performing NPCA / SCA.

[0263] In the above-described Case 2, there are additional issues to consider. For example, depending on the network topology, the timing at which the Non-AP STA and the AP switch to the SCH may differ, as in Case 2-1) and Case 2-2). In that case, the Non-AP STA that switched to the SCH first may attempt meaningless frame exchange with the Non-AP STA that has not switched, which may waste resources. Accordingly, a method may be proposed that allows STAs (e.g., Non-AP and AP) to switch at the same timing (or allows frame exchange to begin only when it can be guaranteed that the receiving STA has switched to the SCH, regardless of which STA switches first). This method can be implemented through Method-1, Method-2, and Method-3 below.

[0264] Method-1)

[0265] According to Method-1, even if all STAs receive the RTS (or MU-RTS) and then receive the responding frame (e.g., CTS) for the RTS (or MU-RTS), they may not switch to the SCH right away. In this case, the STAs wait until they receive the frame following the responding frame (e.g., Data frame related to the RTS), and then can switch to the SCH when the frame (e.g., Data frame) is received. At this time, the transmitting STA only needs to transmit the frame by considering the channel switch delay that occurs when the receiving STA switches to the SCH. This Method-1) can guarantee that the receiving STA has completed the switch to the SCH.

[0266] Method-2)

[0267] An STA that receives a responding frame (e.g., CTS) for RTS (or MU-RTS) and switches can perform back-off considering a preset time (T) for an STA that receives a frame after the responding frame (e.g., a Data frame related to RTS) and switches. In this case, if the value of T is greater than the back-off counter value, the STA can wait for the T-backoff counter value and then start frame exchange. Additionally or alternatively, the T can be set to a value of CTS_TIME + aSIFSTime + aRxPHYStartDelay + Diff (channel switch delay). For example, the Diff (channel switch delay) can have a value of 0 if the channel switch delay of the transmitting STA is greater. Also, for example, the Diff can have a value obtained by subtracting the channel switch delay of the transmitting STA from the channel switch delay of the receiving STA if the channel switch delay of the receiving STA is greater.

[0268] Method-3)

[0269] STAs whose Basic NAV set due to RTS (or MU RTS) is not reset during NAVTimeout (i.e., NAVWaitTime described above) can initiate a switch to SCH after NAVTimeout.

[0270] PPDU version 2 / type (Non-HT PPDU without RTS)

[0271] The above-described second version / type PPDU may be a non-HT (or non-HT duplicate PPDU) that does not include an RTS (or MU-RTS). When the second version / type PPDU is received on the PCH, the conditions for triggering NPCA (or the conditions for switching / accessing the NPCA primary channel (or NPCH)) are determined by considering the following.

[0272] If the received PPDU is a non-HT PPDU (or non-HT duplicate PPDU) that does not include RTS (or MU-RTS), the following should be considered. In other words, if the received PPDU is the second version / type PPDU, the following should be considered. First, OBSS PPDU identification should be performed based on the RA / TA address of the MAC header of the received PPDU. For example, if the PHY / MAC based NPCA is the first value (e.g., 0) (e.g., PHY header based), NPCA / SCA of TXOP-based duration may not be performed for non-HT PPDU that does not include RTS (or MU-RTS). For example, if the PHY / MAC based NPCA is the second value (e.g., 1) or the third value (e.g., 2), OBSS PPDU identification may be performed based on the RA / TA address of the MAC header of the received PPDU. For example, if the TXOP / PPDU based NPCA field value is the first value (e.g., 0), the STA can determine the Duration field value of the MAC header of the received PPDU, decode up to RA / TA of the MAC header, and then switch to SCH.

[0273] Additionally or alternatively, the STA can determine the duration field value of the MAC header of the received PPDU, decode up to RA / TA of the MAC header, perform an FCS check, and then switch to the SCH after confirming the validation check.

[0274] Additionally or alternatively, if the PHY / MAC based NPCA is 1 or 2 and the TXOP / PPDU based NPCA field value is 1, NPCA / SCA may be performed based on the Length field value of the L-SIG field of the received PPDU. In this case, the STA may decode from the MAC header of the received PPDU to RA / TA and then switch to the SCH.

[0275] Additionally or alternatively, the STA may decode the MAC header of the received PPDU to RA / TA, perform an FCS check, and switch to the SCH at the time the validation check is completed.

[0276] Version 3 / Type PPDU (HT PPDU)

[0277] The third version / type PPDU described above may be an HT PPDU. When the third version / type PPDU is received on the PCH, the conditions for NPCA triggering (or conditions for switching / accessing the NPCA primary channel (or NPCH)) are determined by considering the following:

[0278] If the received PPDU is an HT PPDU, OBSS PPDU identification may be performed based on the RA / TA address of the MAC header of the received PPDU. For example, if the PHY / MAC based NPCA is the first value (e.g., 0) (e.g., based on the PHY header), NPCA / SCA may not be performed for the HT PPDU. Accordingly, if the PHY / MAC based NPCA is the second value (e.g., 1) or the third value (e.g., 2), OBSS PPDU identification may be performed based on the RA / TA address of the MAC header of the received PPDU. In addition, if the TXOP / PPDU based NPCA field value is 0, the STA may determine the Duration field value of the MAC header of the received PPDU, confirm the RA / TA of the corresponding MAC header, complete a validation check through an FCS check, and then switch to the SCH.

[0279] Additionally or alternatively, the STA can check the Duration, RA, and TA fields in the MAC header of the received PPDU, skip the validation check through FCS, and switch directly to the SCH.

[0280] Additionally or alternatively, when an A-MPDU included in an HT PPDU is received, the STA can switch to the SCH after completing the FCS check for the first MPDU, after checking the Duration, RA, and TA information included in the MAC header of the first MPDU.

[0281] In addition, for example, if the TXOP / PPDU based NPCA field value is 1, the STA can perform NPCA / SCA based on the Length field value of the L-SIG field of the received PPDU. In this case, the STA can switch to the SCH after decoding from the MAC header of the received PPDU to RA / TA.

[0282] Additionally or alternatively, the STA may switch to the SCH after decoding the MAC header of the received PPDU to the RA / TA and completing a validation check through the FCS check.

[0283] Additionally or alternatively, when an A-MPDU included in an HT PPDU is received, the STA can switch to the SCH after checking the RA and TA information through the MAC header of the first MPDU and completing the FCS check for the first MPDU.

[0284] Version 4 / Type PPDU (if VHT PPDU)

[0285] The above-described 4th version / type PPDU may be a VHT PPDU. When the 4th version / type PPDU is received on the PCH, the conditions for NPCA triggering (or conditions for switching / accessing the NPCA primary channel (or NPCH)) are determined by considering the following:

[0286] If the received PPDU is a VHT PPDU, OBSS PPDU identification can be performed based on the Partial AID and Group ID field values ​​of the VHT-SIG-A field of the PHY header of the received PPDU. If the PHY / MAC based NPCA is the first value (e.g., 0) (e.g., in the case of a PHY header) and the TXOP / PPDU based NPCA field value is the second value (e.g., 1), OBSS PPDU identification can be performed through the Group ID and Partial AID fields of the VHT-SIG-A field. In this case, after the OBSS PPDU identification is performed, the STA can immediately switch to the SCH and perform NPCA / SCA during the PPDU Length based on the LENGTH field of the L-SIG field of the VHT PPDU.

[0287] Additionally or alternatively, if the OBSS PPDU received through the PCH corresponds to the VHT PPDU, the STA may switch to the SCH after completing a validation check through a CRC check of the VHT-SIG-A field of the VHT PPDU.

[0288] In addition, when the TXOP / PPDU based NPCA field is the first value (e.g., 0), OBSS PPDU identification can be performed through the Group ID and Partial AID fields of the VHT-SIG-A field. After OBSS PPDU identification is performed, the STA can decode only the duration field of the MAC header of the VHT PPDU and then immediately switch to the SCH to perform NPCA / SCA.

[0289] Additionally or alternatively, if the OBSS PPDU received through the PCH corresponds to the VHT PPDU, the STA may perform NPCA / SCA based on the PPDU length of the VHT PPDU after completing a validation check through an FCS check of the MAC header of the VHT PPDU.

[0290] Additionally or alternatively, when a version 2 / type PPDU (e.g., Non-HT without RTS), a version 3 / type PPDU (e.g., HT PPDU), and / or a version 4 / type PPDU (e.g., VHT PPDU) described above is received, the STA may obtain information from the MAC header of the received PDU, decode information from the MAC header of the first MPDU of the A-MPDU included in the PPDU, and switch to the SCH after the FCS check is completed. This allows the STA to initiate the switch to the SCH at an earlier time, thereby obtaining a longer TXOP from the SCH.

[0291] Additionally or alternatively, the processing delay (or delay, such as the delay in performing an FCS check) incurred in decoding the MAC header of the received PPDU may vary depending on the capabilities of the STAs. In other words, the point in time when switching starts may vary for each STA. Considering this, switching may be performed after a certain time (e.g., referred to as Starting Switching Alignment Time, and the terminology may be changed) after the received OBSS PPDU, thereby ensuring that STAs (e.g., AP and non-AP STAs) start switching simultaneously. Additionally or alternatively, the Starting Switching Alignment Time may start after the MAC receives the PHYRXEND.indication from the PHY. For example, the value may be defined as SIFS, and may be defined as SIFS + alpha (α). For example, the AP may include Starting Switching Alignment Time information for the Secondary Channel Access Operation. This information can be included in the UHR Operation IE or in a new IE format in the Management frame, including the AP's Beacon and Probe Response. Additionally or alternatively, STAs can switch after the Starting Switching Alignment Time, which begins when the MAC receives the PHYRXEND.indication from the PHY, without the AP's announcement, such as through a NAVTimeout operation.

[0292] PPDU Version 5 / Type

[0293] For example, the 5th version / type PPDU described above may mean a PPDU with a PHY version starting with HE and EHT (PHY version starting with EHT). For example, the PPDU with a PHY version starting with EHT (PHY version starting with EHT) may include an EHT PPDU and an UHR PPDU. For example, the UHR PPDU may mean a PPDU defined by 802.11bn, and the specific name may be changed. When the 5th version / type PPDU is received on the PCH, the condition for NPCA triggering (or the condition for switching / accessing the NPCA primary channel (or NPCH)) is determined by considering the following.

[0294] PPDUs starting from 11ax have a TXOP field in the PHY header. In addition, since a BSS color field is added to the PHY header, it is possible to identify whether a PPDU is received from an OBSS based on the BSS color field. Therefore, for subsequent PPDU formats, including HE PPDUs, STAs can switch based on either the PHY header of the received PPDU or the MAC header of the received PPDU (based on the value set in the PHY / MAC based NPCA). For example, if an OBSS PPDU received on the PCH is a HE PPDU, the HE-SIG-A field includes the corresponding TXOP field and BSS color field. For example, if an OBSS PPDU received on the PCH is an EHT PPDU, the U-SIG field includes the TXOP field and BSS Color field. For example, if the OBSS PPDU received on the PCH is a UHR PPDU, some / all of the U-SIG field of the EHT standard will be maintained (although the PPDU structure is still under discussion). Assuming this, the UHR PPDU will include the TXOP field and the BSS Color field in the U-SIG field, just like the conventional EHT PPDU. For example, based on the above, STAs (e.g., AP and non-AP STAs) that receive an OBSS PPDU corresponding to a HE PPDU through the PCH can (immediately) switch to the SCH after completing decoding up to the BSS color and TXOP fields of the HE-SIG-A field. Additionally or alternatively, a PPDU (e.g., PHY version starting with EHT) having a PHY version starting with EHT, EHT PPDU, UHR PPDU) on the PCH, STAs (e.g., AP and non-AP STAs) can decode the BSS color and TXOP fields of the U-SIG field and then (immediately) switch to the SCH. Based on this, STAs (e.g., AP and non-AP STAs) can switch to the SCH at a faster time based on the PHY Header of the received OBSS PPDU without decoding the MAC header of the received OBSS PPDU. Through this, the STA can have the advantageous technical effect of obtaining a longer TXOP on the SCH while performing NPCA / SCA.

[0295] Additionally or alternatively, if an OBSS PPDU received through the PCH corresponds to a HE PPDU, STAs (e.g., AP and non-AP STAs) that have received the HE PPDU can decode the BSS color and TXOP fields of the HE-SIG-A field included in the received PPDU and perform a validation check through a CRC check for the HE-SIG-A field before switching to the SCH.

[0296] Additionally or alternatively, if an OBSS PPDU received through the PCH corresponds to an EHT / UHR PPDU, STAs (e.g., AP and non-AP STAs) that have received the PPDU can decode the BSS color and TXOP fields of the U-SIG field included in the received PPDU and perform a validation check through a CRC check for the U-SIG field before switching to the SCH.

[0297] Additionally or alternatively, the technical characteristics for cases where OBSS traffic is received after EHT and EHT PPDU are described as follows. In other words, if OBSS traffic (or OBSS PPDU) received via PCH corresponds to EHT PPDU and PPDU defined after EHT (e.g., UHR PPDU), a restriction rule may be additionally or alternatively defined.

[0298] Figure 25 illustrates an example related to channelization. For example, the channelization of Figure 25 may be IEEE 802.11 be (or EHT)-based channelization. For example, according to IEEE 802.11 be-based channelization, 320 MHz MHz (or 320 MHz band / channel / subchannel / resource) may be composed of two adjacent 160 MHz channels in the 6 GHz band. For example, 320 MHz (or 320 MHz band / channel, etc.) may be distinguished as 320MHz-1 and 320MHz-2. For example, 320MHz-1 may be defined as a 320 MHz channel with channel center frequency numbers 31, 95, and 159, and 320MHz-2 may be defined as a 320 MHz channel with channel center frequency numbers 63, 127, and 191.

[0299] As illustrated in Fig. 25, a BSS configured based on 320 MHz can be configured in the 320 MHz-1 band / channel and in the 320 MHz-2 band / channel. For example, depending on the configuration of 320 MHz-1 and 320 MHz-2, the OBSS BSS and the lower 160 MHz (and / or the higher 160 MHz) can overlap.

[0300] Figure 26 illustrates an example of SCA / NPCA performance at 320 MHz.

[0301] For example, when the NPCA BSS operates based on a 320MHz-1 band / channel as in FIG. 26, an OBSS PPDU having a bandwidth of 320 MHz (e.g., an EHT / UHR PPDU having a bandwidth of 320 MHz) may be received. For example, various examples of OBSS PPDUs (e.g., an EHT / UHR PPDU related to an OBSS) may be OBSS1, OBSS2, OBSS3, and / or OBSS4 as illustrated in FIG. 26.

[0302] Additionally or alternatively, OBSS1 of FIG. 26 relates to an example in which a 160 MHz band / channel (e.g., lower 160 MHz band / channel) among the entire 320 MHz band / channel (e.g., 320 MHz-1 band / channel) is configured as a PCH. For example, OBSS2 of FIG. 26 relates to an example in which a 160 MHz band / channel (e.g., lower 160 MHz band / channel) among the entire 320 MHz band / channel (e.g., 320 MHz-2 band / channel) is configured as a PCH. For example, OBSS3 of FIG. 26 relates to an example in which a 160 MHz band / channel (e.g., upper 160 MHz band / channel) among the entire 320 MHz band / channel (e.g., 320 MHz-2 band / channel) is configured as a PCH. For example, OBSS4 of FIG. 26 relates to an example in which a 160 MHz band / channel (e.g., lower 160 MHz band / channel) out of the entire 320 MHz band / channel (e.g., 320 MHz-2 band / channel) is configured as a PCH. For example, the band / channel occupied by OBSS1 of FIG. 26 may completely coincide with the band / channel of the NPCA BSS, and the band / channel occupied by the PCH of OBSS1 may completely coincide with the band / channel occupied by the PCH of NPCA BSS. For example, the band / channel occupied by OBSS2 of FIG. 26 may partially overlap with the band / channel of the NPCA BSS, and the band / channel occupied by the PCH of OBSS2 may not overlap with the NPCA BSS. For example, the band / channel occupied by OBSS3 in FIG. 26 may partially overlap with the band / channel of NPCA BSS, and the band / channel occupied by the PCH of OBSS3 may not overlap with the NPCA BSS (e.g., the band / channel occupied by the PCH of NPCA BSS).For example, the band / channel occupied by OBSS4 of FIG. 26 may partially overlap with the band / channel of NPCA BSS, and the band / channel occupied by PCH of OBSS4 may overlap with the band / channel occupied by NCPH of NPCA BSS.

[0303] As illustrated in FIG. 26, when an OBSS PPDU (e.g., EHT / UHR PPDU) is received, the Bandwidth information / field / subfield included in the U-SIG of the received PPDU may include information regarding the bandwidth value occupied by the corresponding PPDU. Specifically, information regarding whether the corresponding PPDU is transmitted and received through a 320MHz-1 or 320MHz-2 band / channel may be indicated by the U-SIG. When the Bandwidth information / field / subfield of the U-SIG is received, the STA that has received the corresponding PPDU (e.g., EHT / UHR PPDU) may determine whether the SCH on which it performs SCA / NPCA (e.g., the NPCH having a width of 160 MHz as illustrated in FIG. 26) overlaps with the channel / band occupied by OBSS traffic (e.g., OBSS1, OBSS2, OBSS3, and / or OBSS4). For example, SCA / NPCA may not be performed based on the overlap between the band / channel occupied by the NPCH illustrated in FIG. 26 and the received OBSS traffic (e.g., the channel / resource / band through which OBSS1, OBSS2, OBSS3, and / or OBSS4 are transmitted and received). For example, SCA / NPCA may be performed based on the non-overlap between the band / channel related to the NPCH illustrated in FIG. 26 and the band / channel related to the received OBSS traffic (e.g., the channel / resource / band through which OBSS1, OBSS2, OBSS3, and / or OBSS4 are transmitted and received). Through the above judgment, unnecessary switching to SCH / NPCH can be prevented. Meanwhile, the terminology of FIG. 26 may be changed in various ways. For example, the name NPCA BSS used in FIG. 26 may be changed to various names such as SCA BSS, and the technical features of the present specification are not limited by the specific terminology of FIG. 26.

[0304] Additionally or alternatively, when NPCA / SCA is performed according to the present specification, there may be an assumption that the decision on NPCH is made within the Secondary (i.e., half of the BSS operating channel width) channel / subchannel / resource. In other words, the example of FIG. 26 may be an example in which the NPCH is decided within the Secondary (i.e., half of the BSS operating channel width) channel / subchannel / resource. According to this assumption, an AP operating at 320 MHz may decide the Secondary 160 channel (i.e., Secondary 160 MHz) as the NPCH. In other words, in the example of FIG. 26, the NPCH may exist on the Secondary 160 MHz.

[0305] Specific examples related to the above are explained based on the following Examples 1, 2, and 3.

[0306] Example 1)

[0307] Example 1 described below is relevant when the 320MHz bandwidth (e.g., 320MHz-1 band / channel / band / resource) on which the NPCA BSS operates and the PPDU bandwidth (e.g., 320MHz-1 band / channel / band / resource) of the OBSS traffic are identical. For example, the following technical features may be relevant when comparing the NPCA BSS and OBSS1 illustrated in FIG. 26.

[0308] For example, based on the channelization of FIG. 25, the BSS operating channel width (e.g., 320MHz-1 band / channel / band / resource) in which the NPCA BSS operates may be the same as the bandwidth (or band / channel / band / resource) of the OBSS traffic (e.g., EHT PPDU). For example, if the Bandwidth field included in the U-SIG field of the OBSS traffic (e.g., EHT PPDU) indicates 320MHz-1, the bandwidth of the OBSS traffic may be determined to be the same as the BSS operating channel width in which the NPCA BSS operates. In this case, it is preferable that the STA not perform NPCA / SCA because the band / channel related to the NPCH of the NPCA BSS always overlaps with the band / channel related to the OBSS traffic. That is, if the above condition is satisfied, the STA does not switch to the NPCH / SCH.

[0309] Example 2)

[0310] Example 2 described below is relevant when the 320MHz bandwidth (e.g., 320MHz-1 band / channel / band / resource) on which the NPCA BSS operates is different from the PPDU bandwidth (e.g., 320MHz-2 band / channel / band / resource) of the OBSS traffic. For example, the technical features below may be relevant when comparing the NPCA BSS and OBSS2 (or OBSS3) illustrated in FIG. 26.

[0311] For example, based on the channelization of FIG. 25, the BSS operating channel width (e.g., 320MHz-1 band / channel / band / resource) on which the NPCA BSS operates may be different from the bandwidth (or band / channel / band / resource) of the OBSS traffic (e.g., EHT PPDU). For example, if the Bandwidth field included in the U-SIG field of the OBSS traffic (e.g., EHT PPDU) indicates 320MHz-2, 1) the bandwidth of the OBSS traffic overlaps with the 160 MHz channel including the PCH of the NPCA BSS (e.g., Primary 160 MHz), but 2) the bandwidth of the OBSS traffic does not overlap with the 160 MHz channel including the NPCH of the NPCA BSS (e.g., Secondary 160 MHz). For example, if the above condition is satisfied, the STA can perform a switch to NPCH / SCH. In other words, in Example 2, the bands / channels related to the NPCA BSS and the bands / channels related to OBSS2 (or OBSS3) partially overlap, and the bands / channels related to the PCH on the NPCA BSS and the bands / channels related to OBSS2 (or OBSS3) overlap, but the bands / channels related to the NPCH on the NPCA BSS do not overlap with the bands / channels related to OBSS2 (or OBSS3). Based on this, the STA can perform a switch to the NPCH / SCH allocated on the NPCA BSS.

[0312] Example 3)

[0313] Example 3 described below is relevant when the 320MHz bandwidth (e.g., 320MHz-1 band / channel / band / resource) on which the NPCA BSS operates is different from the PPDU bandwidth (e.g., 320MHz-2 band / channel / band / resource) of the OBSS traffic. For example, the following technical features may be relevant when comparing the NPCA BSS and OBSS4 illustrated in FIG. 26.

[0314] For example, based on the channelization of FIG. 25, the BSS operating channel width (e.g., 320MHz-1) in which the NPCA BSS operates and the bandwidth of the OBSS traffic (e.g., EHT PPDU) may be different. For example, if the Bandwidth field included in the U-SIG field of the OBSS traffic (e.g., EHT PPDU) indicates 320MHz-2, the bandwidth of the OBSS traffic may overlap with the 160 MHz channel (e.g., Secondary 160 MHz) containing the NPCH of the NPCA BSS. For example, if the above condition is satisfied, the PCH may not be busy and thus the NPCA execution conditions may not be satisfied, and thus NPCA / SCA may not be performed. As a result, NPCA / SCA may not be performed, and PCH-based channel access may be performed according to the conventional baseline operation. In other words, in Example 3, the bands / channels associated with the NPCA BSS and the bands / channels associated with OBSS4 partially overlap, but the bands / channels associated with the PCH on the NPCA BSS do not overlap with the bands / channels associated with OBSS4. Based on this, the STA does not need to perform NPCA / SCA, and channel access can be performed based on the PCH on the NPCA BSS.

[0315] Additionally or alternatively, the examples related to FIGS. 25 and 26 may be modified in various ways. For example, the above-described examples were described based on the assumption that the NPCH is determined within the Secondary (i.e., half of the BSS operating channel width) channel / subchannel / resource. This assumption may be modified. For example, the NPCH may exist anywhere within the BSS operating channel width. Accordingly, the NPCH may not be configured as the Secondary 160 MHz, but may be allocated / determined on the Secondary 80 MHz in various frequency ranges.

[0316] Figure 27 illustrates an example of SCA / NPCA implementation at 320 MHz. For example, in the example of Figure 26, the NPCH is allocated / determined on the Secondary 160 MHz, but in the example of Figure 27, the NPCH can exist anywhere within the BSS Operating channel width. Accordingly, in the example of Figure 27, the NPCH can be allocated / determined on various Secondary 80 MHz.

[0317] Example 4)

[0318] For example, Example 4 relates to the case where the 320MHz band / channel (e.g., 320MHz-1 band / channel) on which the NPCA BSS operates and the band / channel (e.g., 320MHz-1 band / channel) occupied by the received OBSS traffic (e.g., OBSS PPDU or EHT / UHR PPDU associated with the OBSS) are the same. For example, Example 4 relates to an example in which an NPCA BSS and an OBSS1 are compared in FIG. 27. In other words, Example 4 relates to the case where the band occupied by the NPCA BSS and the band / channel occupied by the OBSS PPDU are completely identical.

[0319] Based on the channelization (e.g., 802.11be / EHT channelization) of FIG. 25, if the channel / band indicated by the U-SIG field of the OBSS traffic (e.g., EHT / UHR PPDU) matches the channel / band related to the BSS operating channel width where the NPCA BSS operates, NPCA / SCA may not be performed. For example, in the above case, the STA may not switch to NPCH. In other words, as in the example of OBSS1 of FIG. 27, if the band / channel indicated by the Bandwidth field of the U-SIG of the OBSS traffic (EHT PPDU) corresponds to 320 MHz-1 and the band / channel corresponding to the BSS operating channel width is also 320 MHz-1, NPCA / SCA may not be performed. This is because NPCH and OBSS traffic (e.g., EHT / UHR PPDU related to OBSS) on NPCA BSS always overlap.

[0320] Example 5)

[0321] For example, Example 5 may be relevant when the 320 MHz band / channel (e.g., 320 MHz-1 band / channel) on which the NPCA BSS operates and the band / channel (e.g., 320 MHz-1 band / channel) occupied by OBSS traffic (e.g., OBSS PPDU or EHT / UHR PPDU associated with the OBSS) are not the same. In other words, Example 5 may be relevant when the 320 MHz band / channel (e.g., 320 MHz-1 band / channel) on which the NPCA BSS operates and the band / channel (e.g., 320 MHz-1 band / channel) occupied by OBSS traffic (e.g., OBSS PPDU or EHT / UHR PPDU associated with the OBSS) partially overlap. In other words, Example 5 is relevant to an example in which an NPCA BSS and an OBSS2 (or OBSS3) are compared in FIG. 27. In other words, Example 5 relates to the case where the band occupied by the NPCH on the NPCA BSS overlaps with the band / channel occupied by the OBSS PPDU.

[0322] Based on the channelization (e.g., 802.11be / EHT channelization) of FIG. 25, if the channel / band indicated by the U-SIG field of the OBSS traffic (e.g., EHT / UHR PPDU) partially overlaps with the channel / band related to the BSS operating channel width where the NPCA BSS operates, NPCA / SCA may not be performed. In other words, as in the example of OBSS2 (or OBSS3) of FIG. 27, if the band / channel indicated by the Bandwidth field of the U-SIG of the OBSS traffic (e.g., EHT / UHR PPDU) corresponds to 320 MHz-2 and the band / channel corresponding to the BSS operating channel width is also 320 MHz-1, NPCA / SCA may not be performed. In other words, if the band / channel indicated by the Bandwidth field of the U-SIG of the NPCH located at Secondary 80MHz and the OBSS traffic (EHT / UHR PPDU) overlap, NPCA / SCA may not be performed.

[0323] Example 6)

[0324] For example, Example 6 may be relevant when the 320 MHz band / channel (e.g., 320 MHz-1 band / channel) on which the NPCA BSS operates and the band / channel (e.g., 320 MHz-2 band / channel) occupied by OBSS traffic (e.g., OBSS PPDU or EHT / UHR PPDU associated with the OBSS) are not the same. In other words, Example 6 may be relevant when the 320 MHz band / channel (e.g., 320 MHz-1 band / channel) on which the NPCA BSS operates and the band / channel (e.g., 320 MHz-2 band / channel) occupied by OBSS traffic (e.g., OBSS PPDU or EHT / UHR PPDU associated with the OBSS) partially overlap. In other words, Example 6 is relevant to an example in which an NPCA BSS and an OBSS4 are compared in FIG. 27. In other words, Example 6 relates to the case where the band / channel occupied by the NPCH on the NPCA BSS does not overlap with the band / channel occupied by the OBSS PPDU.

[0325] In the case of Example 6, when judged based on the channelization (e.g., 802.11be / EHT channelization) of Fig. 25, the BSS operating channel width where the NPCA BSS operates is related to the 320MHz-1 band / channel, and the Bandwidth field of the U-SIG of the OBSS traffic (e.g., EHT / UHR PPDU) is related to the 320MHz-2 band / channel. For example, in the case of OBSS4 of Fig. 27, the OBSS traffic (e.g., EHT / UHR PPDU) may not overlap with the NPCH. In this case, the PCH is not busy, so the NPCA execution condition is not satisfied, and thus NPCA / SCA may not be performed. As a result, PCH-based channel access is performed based on the conventional baseline operation. In other words, in Example 6, although the bands / channels associated with the NPCA BSS and the bands / channels associated with OBSS4 partially overlap, NPCA / SCA does not need to be performed because the bands / channels associated with the PCH on the NPCA BSS do not overlap with the bands / channels associated with OBSS4. Based on this, the STA can perform channel access based on the PCH on the NPCA BSS.

[0326] Examples of this specification may be expressed in various procedure flowcharts.

[0327] For example, FIG. 21 is a flowchart of a procedure related to a transmitting STA. The operation of FIG. 21 may be performed by an AP or a non-AP STA. For example, the AP performing FIG. 21 may be any one of multiple APs affiliated with a multi-link device (e.g., AP MLD). For example, the non-AP STA performing FIG. 21 may be any one of multiple non-AP STAs affiliated with a multi-link device (e.g., non-AP STA MLD).

[0328] As shown in step S2110, when an STA receives a frame (e.g., OBSS frame) from another BSS, it can set a Basic NAV on the Primary channel.

[0329] The illustrated step S2120 is relevant when operating based on the aforementioned Case 1. For example, as described above, Case 1 may be relevant when receiving an OBSS PPDU on the PCH and immediately switching to the SCH. For example, as in the illustrated step S2120, the STA may immediately switch to the SCH (e.g., the NPCA primary channel, the S20 channel, or the NPCH) and perform back-off.

[0330] The illustrated step S2130 is relevant to the case where the STA operates based on the above-described Case 2 (e.g., including Case 2-1 and Case 2-2). For example, as described above, an STA operating based on Case 2 may defer access or switch to the SCH for the maximum NAV wait time (e.g., NAVWaittime) rather than immediately switching to the SCH after receiving an OBSS PPDU on the PCH. If PPDU detection (e.g., detection of CTS and / or Data frame) is performed during the NAV wait time, the STA may switch / access to the SCH. For example, as in the illustrated step S2130, if PPDU Detection is confirmed while the STA is waiting for the wait time (e.g., NAVWaitTime), the STA may immediately switch to the SCH (e.g., NPCA primary channel or NPCH or S20 channel) and perform Back-off.

[0331] For example, after step S2120 or step S2130 is performed, step S2130 may be performed. For example, as in step S2140 illustrated, if the BC counter becomes 0 in the SCH (e.g., NPCA primary channel or NPCH) on which back-off is performed, the STA may perform CCA on another SCH (e.g., S40 / S80).

[0332] For example, if channel extension is applied to an additional SCH, step S2150 may be performed. For example, as illustrated in step S2150, the STA may transmit a PPDU including a frame having a bandwidth that includes the SCH for which back-off has been performed and another SCH for which the CCA result is determined to be Idle.

[0333] For example, FIG. 22 is a procedure flow diagram related to a receiving STA. The operation of FIG. 22 may be performed by an AP or a non-AP STA. For example, the AP performing FIG. 22 may be any one of multiple APs affiliated with a multi-link device (e.g., AP MLD). For example, the non-AP STA performing FIG. 22 may be any one of multiple non-AP STAs affiliated with a multi-link device (e.g., non-AP STA MLD).

[0334] As shown in step S2210, when an STA receives a frame (e.g., OBSS frame) from another BSS, it can set a Basic NAV on the Primary channel.

[0335] The illustrated step S2220 is relevant when operating based on the aforementioned Case 1. For example, as described above, Case 1 may be relevant when receiving an OBSS PPDU on the PCH and immediately switching to the SCH. For example, as in the illustrated step S2220, the STA may immediately switch to the SCH (e.g., NPCA primary channel, NPCH, or S20 channel) and perform back-off.

[0336] The illustrated step S2230 is relevant to the case where the STA operates based on the above-described Case 2 (e.g., including Case 2-1 and Case 2-2). For example, as described above, the STA operating based on Case 2 may defer access or switch to the SCH for the maximum NAV waiting time (e.g., NAVWaittime) instead of immediately switching to the SCH after receiving an OBSS PPDU on the PCH. If PPDU detection (e.g., detection of CTS and / or Data frame) is performed during the NAV waiting time, the STA may switch / access to the SCH. For example, as in the illustrated step S2230, if PPDU Detection is confirmed while the STA is waiting for the waiting time (e.g., NAVWaitTime), the STA may immediately switch to the SCH (e.g., NPCA primary channel or NPCH or S20 channel) and perform Back-off.

[0337] For example, after step S2220 or step S2230 is performed, step S2230 may be performed. For example, as in step S2240 shown, when a PPDU including at least one frame is received while performing back-off, the STA may determine whether the frame is addressed to itself (e.g., determine whether the RA field matches the MAC address of the receiving STA).

[0338] If the judgment result indicates that the frame is addressed to the STA, step S2260 may be performed. For example, according to step S2260, the STA may decode the frame body of the received frame.

[0339] If the frame is not addressed to the STA, step S2250 may be performed. For example, according to step S2250, the STA may set the NAV based on the value of the duration field included in the MAC header of the received frame.

[0340] The examples in this specification may be modified in various ways. The examples in this specification may be modified in consideration of the following.

[0341] For example, an STA (e.g., an AP or a non-AP STA) performing NPCA / SCA may transmit a frame / PPDU on an SCH even during the time when a NAV (e.g., a Basic NAV set by a received OBSS PPDU) is set on a PCH (e.g., a channel including a Primary 20 MHz channel). For example, the STA may transmit a PPDU on at least one SCH that is in an IDLE state determined through a backoff (and a CCA result of one or more SCHs on which backoff is not performed) performed on one or more SCHs (e.g., a channel including an S20 channel or an NPCA primary channel). For example, the PPDU may have preamble puncturing performed on a subchannel corresponding to the PCH.

[0342] Additionally or alternatively, a TXOP acquired for transmitting a frame / PPDU on the SCH may be set to end before the NAV (e.g., Basic NAV) on the PCH ends. For example, the length of the TXOP may be set / indicated via a duration / ID field of the corresponding frame (e.g., a MAC header of the frame / PPDU transmitted on the SCH). For example, the value of the duration / ID field may be set to a value corresponding to a time required for an exchange of a frame / PPDU following the corresponding frame / PPDU (e.g., a time including an interframe gap (IFS)).

[0343] Additionally or alternatively, the EDCA Parameter Set for each SCH on which back-off is performed may be set to the EDCA Parameter Set in the PCH, the MU EDCA Parameter Set, or a new EDCA Parameter Set. This EDCA Parameter Set may be applied equally to all SCHs or individually (or differently) from each other.

[0344] In this specification, an STA (e.g., an AP or non-AP STA) receiving a frame transmitted via SCA / NPCA can perform frame detection on the SCH (e.g., S20 channel or NPCA primary Channel or NPCH) even during the time when a NAV (e.g., Basic NAV) is set in the PCH. For example, the STA (e.g., an AP or non-AP STA) may perform backoff on the SCH because it has a frame to transmit, or may attempt to receive a frame addressed to itself on the SCA even when it has no frame to transmit. In addition, the STA may perform NAV setting / resetting based on the value of the duration / ID field of a frame detected on the SCH.

[0345] Additionally or alternatively, the EDCA Parameter Set for each SCH on which back-off is performed may be set to the EDCA Parameter Set in the PCH, the MU EDCA Parameter Set, or a new EDCA Parameter Set. This EDCA Parameter Set may be applied equally or individually (or differently) to all SCHs.

[0346] Additionally or alternatively, an STA (e.g., an AP or non-AP STA) may trigger NPCA, switch to the NPCA primary channel (or NPCH), or access the NPCA primary channel based on the technical features of Case 1 or Case 2 described above, if Basic NAV is set on the PCH due to an OBSS PPDU. For example, an STA based on Case 1 described above may immediately trigger NPCA (or switch to the NPCA primary channel, or access the NPCA primary channel) based on the Basic NAV being set on the PCH.

[0347] Additionally or alternatively, an STA based on the above-described Case 2 may not immediately trigger NPCA (or switch to the NPCA primary channel (or NPCH), or access the NPCA primary channel) based on the Basic NAV being set in the PCH. Specifically, an STA based on the above-described Case 2 may not immediately trigger NPCA, but may wait (or defer the triggering of NPCA, defer the access to NPCA, or defer the switch to SCH) for a preset waiting time (e.g., referred to as NAVWaitTime). For example, during the above-described waiting, if PPDU detection is performed on the STA, NPCA may be triggered (or switched to the NPCA primary channel, or accessed). For example, the PPDU detection may mean that a PPDU including a CTS is received on the PCH, or a PPDU including a Data frame related to an RTS / CTS exchange is received on the PCH. As previously explained, the NAV wait time or NAVWaitTime can be calculated based on parameters widely known in wireless LAN systems. For example, the NAVWaitTime can be calculated as (2 Х aSIFSTime) + (CTS_Time) + aRxPHYStartDelay + (2 Х aSlotTime), and the CTS_Time can be calculated based on the length and PHY data rate for the CTS frame.

[0348] Figure 23 is another flowchart illustrating an example of the present specification.

[0349] Steps S2310 and S2320 illustrated relate to an example of the present specification. The operation of FIG. 23 may be performed by an AP or a non-AP STA. For example, the operation of FIG. 23 may be performed by a device performing FIG. 21 or FIG. 22.

[0350] For example, as in step S2310, the STA can obtain information related to the triggering of NPCA. For example, the procedure for obtaining information related to the triggering of NPCA (or information related to the trigger condition) may be a procedure for obtaining information about an OBSS PPDU (or an OBSS signal / traffic / frame, etc.) received on the PCH (a channel including a primary 20 MHz channel). Additionally or alternatively, step S2310 may include a procedure for determining whether the BSS PPDU received on the PCT is an OBSS PPDU or an Intra-BSS PPDU. A specific method for performing OBSS PPDU identification based on the Version / Type of the received PPDU may be the same as the example of the present specification described above.

[0351] Additionally or alternatively, step S2310 may include at least one of a procedure for receiving an OBSS PPDU by the STA, a procedure for determining whether the OBSS PPDU includes RTS / MU-RTS, and / or a procedure for determining whether the OBSS PPDU is a non-HT / HT / VHT / HE / EHT / UHR PPDU. Additionally or alternatively, step S2310 may include a process for confirming / acquiring a TXOP length and / or a PPDU length of the OBSS PPDU by the STA.

[0352] For example, as in step S2320, the STA may perform a switch to an NPCA primary channel (e.g., a channel including an SCH or an S20 channel) based on information related to the triggering of the NPCA. Additionally or alternatively, performing a switch to the NPCA primary channel may be expressed as attempting / performing access to the NPCA primary channel or attempting / performing NPCA / SCA.

[0353] As in step S2320, a switch to an NPCA primary channel (e.g., a channel including an SCH or an S20 channel) may be performed based on information related to the triggering of the NPCA. For example, if various triggering conditions proposed in this specification are satisfied, the STA (e.g., an AP or a non-AP STA) may initiate / attempt a switch to the SCH (or NPCA primary channel or NPCH) described above. For example, if various triggering conditions proposed in this specification are not satisfied, the STA (e.g., an AP or a non-AP STA) may not initiate / attempt a switch to the SCH (or NPCA primary channel) described above.

[0354] For example, information related to the triggering of the NPCA may include information about the Basic NAV related to the PCH. For example, an STA operating based on Case-1 of the present specification may, according to step S2320, immediately perform a switch to an NPCA primary channel (e.g., a channel including an SCH or an S20 channel) when the Basic NAV is set on the PCH.

[0355] For example, information related to triggering of the NPCA may include information related to the Version / type of the received PPDU (e.g., OBSS PPDU). In addition, information related to triggering of the NPCA may include information on whether the received PPDU (e.g., OBSS PPDU) includes RTS (or MU-RTS). Accordingly, an STA operating based on Case 2 of the present specification may wait for the maximum NAVWaitTime without immediately performing a switch to an NPCA primary channel (e.g., a channel including an SCH or S20 channel) according to step S2320 when the received PPDU (e.g., OBSS PPDU) includes RTS (or MU-RTS). While the STA is waiting for NAVWaitTime, if a response frame (e.g., a Data frame or CTS related to RTS / CTS exchange) is received on the PCH, the STA can immediately perform a switch to an NPCA primary channel (e.g., a channel including an SCH or S20 channel).

[0356] Additionally or alternatively, when steps S2310 and S2320 are performed, at least one of steps S2140 and S2150 may be performed sequentially. Additionally or alternatively, when steps S2310 and S2320 are performed, at least one of steps S2240 to S2260 may be performed sequentially.

[0357] Figure 24 is another flowchart illustrating an example of the present specification. The operations of Figure 24 may be performed by an AP or a non-AP STA. For example, the operations of Figure 24 may be performed by a device performing Figures 21, 22, or 23.

[0358] According to the illustrated step S2410, the STA can receive an Overlapping Basic Service Set (OBSS) signal. For example, the OBSS signal can be the OBSS PPDU (or traffic / frame, etc.). For example, the OBSS signal can be received through the PCH (a channel including the Primary 20 MHz channel) described above. For example, a Basic NAV can be set for the PCH based on the OBSS signal.

[0359] According to the illustrated step S2420, the STA may perform access to a Non-primary Channel Access (NPCA) primary channel by the STA based on the OBSS signal. For example, access to the NPCA primary channel may include performing switching to the NPCA primary channel by the STA. For example, access to the NPCA primary channel may mean performing the NPCA / SCH operation. For example, access to the NPCA primary channel may mean triggering the NPCA. For example, when access to the NPCA primary channel is performed, the STA may perform a back-off for the NPCA primary channel.

[0360] According to step S2420, access / switch for the NPCA primary channel is performed based on the received OBSS signal (e.g., OBSS PPDU). For example, the start time of access / switch for the NPCA primary channel can be determined based on the received OBSS signal (e.g., OBSS PPDU). For example, whether to access / switch for the NPCA primary channel can be determined based on the received OBSS signal (e.g., OBSS PPDU).

[0361] According to step S2420, the access / switch to the NPCA primary channel may be performed based on at least one of a Basic NAV (Network Allocation Vector) set for the primary channel based on the OBSS signal and a wait time related to the OBSS signal. In other words, the access / switch to the NPCA primary channel may be performed immediately after the Basic NAV is set, or may be performed after waiting for a wait time related to the OBSS signal (e.g., the NAV Wait Time described above). In other words, the STA may defer access to the NPCA primary channel based on the NAV wait time (e.g., the NAV Wait Time described above). For example, if a CTS or a Data frame (related to an RTS / CTS exchange) is received (over the PCH) during the NAV waiting time, the STA may immediately perform access to the NPCA primary channel based on the CTS / Data-frame detection. In other words, if the STA receives the CTS during the NAV waiting time, the STA may perform access to the NPCA primary channel based on receiving a data frame or the CTS through the primary channel. This case relates to an example of Case 2 described herein. For example, even if the received PPDU includes an RTS / MU-RTS, the STA may (immediately) perform access to the NPCA primary channel based on the Basic NAV without considering the NAV waiting time (e.g., the NAV Wait Time described above). This case relates to an example of Case 1 described herein. For example, the NAV waiting time (e.g.,, the NAV Wait Time described above can be calculated as (2 Х aSIFSTime) + (CTS_Time) + aRxPHYStartDelay + (2 Х aSlotTime) based on parameters well known in the art. In other words, the NAV Wait Time can be set based on the length of the RTS (or CTS related to MU-RTS).

[0362] Additionally or alternatively, when steps S2410 and S2420 are performed, at least one of steps S2140 and S2150 may be performed sequentially. Additionally or alternatively, when steps S2410 and S2420 are performed, at least one of steps S2240 to S2260 may be performed sequentially.

[0363] Additionally or alternatively, when steps S2410 and S2420 are performed, transmission and reception of PPDUs on channels other than the PCH are possible due to NPCA / SCA. Accordingly, based on access to the NPCA primary channel, the STA can perform PPDU transmission based on a first channel including the NPCA primary channel. Also, for example, based on access to the NPCA primary channel, the STA can receive PPDUs through a second channel including the NPCA primary channel. For example, the PPDU transmitted and received through the first / second channel may be at least one of the non-HT (non-High Throughput) PPDU (Physical Protocol Data Unit), HT (High Throughput) PPDU, VHT (Very High Throughput) PPDU, HE (High Efficiency) PPDU, EHT (Extremely High Throughput) PPDU, and / or UHR (Ultra High Reliability) PPDU described above.

[0364] The technical features of the present disclosure may be implemented by various devices. The devices of the present disclosure may be the devices described in FIG. 1 / FIG. 14. The devices of the present disclosure may include at least one processor; and at least one computer memory operably connectable to the at least one processor, the computer memory storing instructions for performing operations based on execution by the at least one processor.

[0365] For example, the processor may be a processor described in FIG. 1 and / or FIG. 14. That is, as described above, the processor of the present specification may include at least one of a digital signal processor (DSP), a central processing unit (CPU), a graphics processing unit (GPU), and a modem (modulator and demodulator). The processor may include not only computers having various architectures such as single / multiprocessor architecture, sequential (Von Neumann) / parallel architecture, but also specialized circuits such as FPGAs, ASICs, signal processing devices, and other devices. For example, the processor of the present specification may be a SNAPDRAGON® series processor manufactured by Qualcomm®, an EXYNOS® series processor manufactured by Samsung®, an A series processor manufactured by Apple®, a HELIO® series processor manufactured by MediaTek®, an ATOM® series processor manufactured by INTEL®, or a processor that enhances the same.

[0366] For example, the instructions may refer to computer program instructions executed by the at least one processor. The (computer program) instructions provide logic and / or routines that enable the technical features of the present specification to be performed by the processor. The at least one processor can load and execute a computer program by reading the at least one memory.

[0367] The computer program(s) defined by the above instructions may be delivered to the device (e.g., STA) of the present specification via an appropriate delivery mechanism. The delivery mechanism may be, for example, a computer-readable storage medium, a computer program product, a memory device, a recording medium such as a CD-ROM or DVD, or a product tangibly embodying the computer program. The delivery mechanism may be a signal configured to reliably transmit the computer program via a wireless or electrical connection.

[0368] The above (computer program) instructions may include software or firmware for a programmable processor (e.g., programmable content of a hardware device whether instructions for a processor, or configuration settings for a fixed-function device, gate array or programmable logic device, etc.).

[0369] For example, the memory may be the memory described in FIG. 1 and / or FIG. 14. That is, as described above, the memory of the present specification may store control information related to the operation of the STA of the present specification or information about signals transmitted and received by the STA (e.g., PPDU including management / control / data frames).

[0370] The technical features of this specification may be implemented in at least one computer-readable recording medium (CRM). The CRM includes instructions that are executed by at least one processor as described above. The instructions stored in the CRM may be computer program instructions as described above.

[0371] The device of the present disclosure may further include a transceiver. The transceiver may be operably connectable to the memory / processor, etc. The transceiver may be the transceiver illustrated in FIG. 1 and / or FIG. 14.

[0372] The technical features of this specification described above are applicable to various applications and business models. For example, the technical features described above can be applied to wireless communication in devices that support artificial intelligence (AI).

[0373] Artificial intelligence (AI) is the study of artificial intelligence or the methodologies for creating it, while machine learning (ML) defines various problems in the field of AI and studies the methodologies for solving them. Machine learning is also defined as an algorithm that improves performance on a task through consistent experience.

[0374] An artificial neural network (ANN) is a model used in machine learning. It can refer to a model with problem-solving capabilities, consisting of artificial neurons (nodes) formed by the connection of synapses to form a network. An ANN can be defined by the connection patterns between neurons in different layers, the learning process that updates model parameters, and the activation function that generates output values.

[0375] An artificial neural network may include an input layer, an output layer, and optionally one or more hidden layers. Each layer contains one or more neurons, and the artificial neural network may include synapses connecting neurons. In an artificial neural network, each neuron can output a function value of an activation function based on input signals, weights, and biases received through the synapses.

[0376] Model parameters are parameters determined through learning, including synaptic connection weights and neuron biases. Hyperparameters are parameters that must be set before learning in machine learning algorithms, including the learning rate, number of iterations, mini-batch size, and initialization function.

[0377] The goal of artificial neural network training can be seen as determining model parameters that minimize a loss function. The loss function can be used as an indicator for determining optimal model parameters during the artificial neural network training process.

[0378] Machine learning can be classified into supervised learning, unsupervised learning, and reinforcement learning depending on the learning method.

[0379] Supervised learning refers to a method for training an artificial neural network when given labels for the training data. The labels can refer to the correct answer (or output value) that the artificial neural network must infer when the training data is input to the artificial neural network. Unsupervised learning can refer to a method for training an artificial neural network when the training data is not given labels. Reinforcement learning can refer to a learning method in which an agent defined within a given environment is trained to select actions or action sequences that maximize the cumulative reward in each state.

[0380] Machine learning implemented with a deep neural network (DNN) containing multiple hidden layers among artificial neural networks is also called deep learning, and deep learning is a subset of machine learning. Hereinafter, the term "machine learning" is used to encompass deep learning.

[0381] Additionally, the above-described technical features can be applied to wireless communication of robots.

[0382] A robot can be defined as a machine that automatically performs or operates a given task based on its own capabilities. Specifically, a robot capable of perceiving its environment, making independent judgments, and performing actions can be called an intelligent robot.

[0383] Robots can be categorized into industrial, medical, household, and military applications based on their intended use or field. Robots are equipped with actuators or motors, enabling them to perform various physical actions, such as moving robot joints. Furthermore, mobile robots incorporate wheels, brakes, and propellers into their actuators, enabling them to move on the ground or fly in the air.

[0384] Additionally, the above-described technical features can be applied to devices that support extended reality.

[0385] Extended reality is a general term for virtual reality (VR), augmented reality (AR), and mixed reality (MR). VR technology presents real-world objects and backgrounds as CG images only, AR technology presents virtual CG images over images of real objects, and MR technology is a computer graphics technology that blends and combines virtual objects with the real world.

[0386] MR technology is similar to AR in that it presents both real and virtual objects simultaneously. However, while AR uses virtual objects to complement real objects, MR uses virtual and real objects on an equal footing.

[0387] XR technology can be applied to HMD (Head-Mount Display), HUD (Head-Up Display), mobile phones, tablet PCs, laptops, desktops, TVs, digital signage, etc., and devices to which XR technology is applied can be called XR devices.

Claims

1. A step of receiving an OBSS (Overlapping Basic Service Set) signal by a STA (station); and Based on the above OBSS signal, access to the NPCA (Non-primary Channel Access) primary channel is performed by the STA, Access to the above NPCA primary channel is performed based on at least one of a Basic NAV (Network Allocation Vector) set for the primary channel based on the OBSS signal and a wait time related to the OBSS signal. Including method.

2. In paragraph 1, Access to the above NPCA primary channel includes performing switching to the NPCA primary channel by the STA, Based on the switching to the above NPCA primary channel, the STA performs a back-off for the above NPCA primary channel. method.

3. In paragraph 1, The above OBSS signal includes RTS or MU-RTS, The wait time related to the above OBSS signal is the NAV wait time related to the RTS or MU-RTS, The above NAV waiting time is set based on the length of the CTS related to the RTS or MU-RTS. method.

4. In paragraph 3, The above STA defers access to the NPCA primary channel based on the NAV waiting time. method.

5. In paragraph 4, If the STA receives the CTS during the above NAV waiting time, The above STA performs access to the NPCA primary channel based on receiving a data frame or the CTS through the primary channel. method.

6. In paragraph 1, The above OBSS signal includes RTS or MU-RTS, The above STA performs access to the NPCA primary channel based on the Basic NAV without considering the wait time related to the OBSS signal. method.

7. In paragraph 1, The above primary channel includes a Primary 20 MHz channel, and the above NPCA primary channel includes a Secondary 20 MHz channel. method.

8. In paragraph 1, The above OBSS signal includes at least one of a non-HT (non-High Throughput) PPDU (Physical Protocol Data Unit), an HT (High Throughput) PPDU, a VHT (Very High Throughput) PPDU, a HE (High Efficiency) PPDU, an EHT (Extremely High Throughput) PPDU, and / or a UHR (Ultra High Reliability) PPDU, Based on the PPDU version of the above OBSS signal, the time at which access to the NPCA (Non-primary Channel Access) primary channel is performed is determined. method.

9. In paragraph 1, Based on access to the above NPCA primary channel, the STA performs PPDU transmission based on a first channel including the above NPCA primary channel. method.

10. In paragraph 1, Based on access to the above NPCA primary channel, the STA receives a PPDU through a second channel including the above NPCA primary channel. method.

11. In paragraph 1, The above STA is an AP (Access Point) or a non-AP STA. method.

12. At least one processor included in the STA (station); and At least one computer memory operably connectable to said at least one processor, said computer memory storing instructions for performing operations based on being executed by said at least one processor, The instructions of at least one computer memory, A step of receiving the above STA (station) OBSS (Overlapping Basic Service Set) signal; and Based on the above OBSS signal, access to the NPCA (Non-primary Channel Access) primary channel is performed by the STA, Access to the above NPCA primary channel is a step performed based on at least one of a Basic NAV (Network Allocation Vector) set for the primary channel based on the OBSS signal and a wait time related to the OBSS signal. Performing the action of STA.

13. In the 12th paragraph, the command of at least one computer memory performs an operation related to any one of the 2nd to 11th paragraphs. STA.

14. In a wireless local area network (WLAN) system, at least one computer readable medium including instructions based on being executed by at least one processor, A step of receiving an OBSS (Overlapping Basic Service Set) signal by a STA (station); and Based on the above OBSS signal, access to the NPCA (Non-primary Channel Access) primary channel is performed by the STA, Access to the above NPCA primary channel is performed based on at least one of a Basic NAV (Network Allocation Vector) set for the primary channel based on the OBSS signal and a wait time related to the OBSS signal. Performing an operation that includes Recording medium.

15. In the 14th paragraph, the recording medium performs an operation related to any one of the 2nd to 11th paragraphs. Recording medium.

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