Secondary channel access method and apparatus in wireless LAN system

Abstract

A method and an apparatus for operating in a wireless LAN system are disclosed. According to one embodiment of the present disclosure, a method performed by a first station (STA) in a wireless LAN system comprises the steps of: transmitting, to a second AP, a request frame including first information related to a non-primary channel access procedure on a first channel of a first basic service set (BSS); receiving a response frame from the second AP, the response frame including second information indicating whether to accept the request frame; and transmitting, to the at least one STA, a first frame including third information related to a non-primary channel access procedure on the first channel based on the request frame and the response frame, in which the first channel of the first BSS related to the first AP may completely or partially overlap with the second channel of the second BSS related to the second AP.

Description

Technical Field

[0001] This disclosure relates to methods and apparatus for secondary channel access in wireless local area network (WLAN) systems. Background Technology

[0002] New technologies have been introduced for Wireless LANs (WLANs) to improve transmission rates, increase bandwidth, enhance reliability, reduce errors, and decrease latency. Within WLAN technology, the IEEE 802.11 series of standards can be referred to as Wi-Fi. For example, recent technologies introduced into WLAN include the Ultra High Throughput (VHT) enhancement of the 802.11 ac standard and the High Efficiency (HE) enhancement of the IEEE 802.11 ax standard.

[0003] To provide a more advanced wireless communication environment, improved techniques for Extremely High Throughput (EHT) are being discussed. For example, techniques for MIMO and multiple access point (AP) coordination that support increased bandwidth, efficient use of multiple frequency bands, and increased spatial flow are being investigated. Specifically, various techniques are being explored to support low latency or real-time traffic. Furthermore, new technologies to support Ultra-High Reliability (UHR), including improvements or extensions to EHT techniques, are being discussed. Summary of the Invention

[0004] Technical issues

[0005] The technical problem of this disclosure is to provide a method and apparatus for secondary channel access in a wireless LAN system.

[0006] The technical problem of this disclosure is to provide a method and apparatus in a wireless LAN system for announcing information related to access to one or more secondary channels in addition to the primary channel.

[0007] The technical problem of this disclosure is to provide a method for multiple access points (APs) in a wireless LAN system to negotiate information related to secondary channels for secondary channel access.

[0008] The technical objectives to be achieved by this disclosure are not limited to those described above, and other technical objectives not described herein will be clearly understood by those skilled in the art through the following description.

[0009] Technical solution

[0010] A method performed by a first access point (STA) in a wireless LAN system according to one aspect of the present disclosure may include the following steps: sending a request frame to a second AP, the request frame including first information related to a non-master channel access procedure on a first channel of a first basic service set (BSS); receiving a response frame from the second AP, the response frame including second information indicating whether the request frame is accepted; and based on the request frame and the response frame, sending a first frame including third information related to a non-master channel access procedure on the first channel to at least one STA, wherein the first channel of the first BSS associated with the first AP may wholly or partially overlap with the second channel of the second BSS associated with the second AP.

[0011] A method performed by a second access point (STA) in a wireless LAN system according to one aspect of this disclosure may include the following steps: receiving a request frame from a first AP, the request frame including first information related to a non-primary channel access procedure on a first channel of a first basic service set (BSS); and sending a response frame to the first AP, the response frame including second information indicating whether the request frame is accepted, and based on the request frame and the response frame, sending a first frame including third information related to a non-primary channel access procedure on the first channel from the first AP to at least one STA, and the first channel of the first BSS associated with the first AP may overlap wholly or partially with the second channel of the second BSS associated with the second AP.

[0012] Technical effect

[0013] According to various embodiments of this disclosure, methods and apparatus for secondary channel access in a wireless LAN system can be provided.

[0014] According to various embodiments of the present disclosure, methods and apparatus for announcing information related to access to one or more secondary channels in addition to the primary channel can be provided in a wireless LAN system.

[0015] Various embodiments of this disclosure can provide a method for multiple access points (APs) to negotiate secondary channel access in a wireless LAN system.

[0016] Various embodiments of this disclosure enable more efficient communication using media and channels in wireless LAN systems.

[0017] The effects achievable by this disclosure are not limited to those described above, and those skilled in the art can clearly understand other effects not described herein through the following description. Attached Figure Description

[0018] The accompanying drawings, which are included as part of the detailed description of this disclosure, provide embodiments of the disclosure and, together with the detailed description, describe the technical features of the disclosure.

[0019] Figure 1 A configuration block diagram of a wireless communication device according to an embodiment of the present disclosure is illustrated.

[0020] Figure 2 This is a diagram illustrating an exemplary structure of a WLAN system to which this disclosure can be applied.

[0021] Figure 3 This is a diagram used to illustrate the link establishment process that can be applied to this disclosure.

[0022] Figure 4 This is a diagram used to illustrate the backoff processing that can be applied to this disclosure.

[0023] Figure 5 This is a diagram illustrating the CSMA / CA-based frame transmission operation that can be applied to this disclosure.

[0024] Figure 6 This is a diagram illustrating an example of a frame structure that can be used in a WLAN system to which this disclosure may be applied.

[0025] Figure 7 This is a diagram illustrating an example of a PPDU as defined in the IEEE 802.11 standard of this disclosure.

[0026] Figure 8 This is a diagram illustrating an example of channel access based on the master channel that can be applied according to this disclosure.

[0027] Figure 9 This is a flowchart illustrating a method for a first AP to perform channel access according to an embodiment of the present disclosure.

[0028] Figure 10 This is a flowchart illustrating a method for a second AP to perform channel access according to an embodiment of the present disclosure.

[0029] Figure 11 This is a diagram illustrating an example of secondary channel access according to this disclosure.

[0030] Figure 12 This is a diagram illustrating the overlap of BSS channels between APs according to an embodiment of the present disclosure.

[0031] Figure 13 This is a diagram illustrating the process by which an AP sends announcement information related to SCA according to an embodiment of this disclosure.

[0032] Figure 14 This is a diagram illustrating the backoff process when the bandwidth of the BSS operation channel according to an embodiment of the present disclosure is 160 MHz.

[0033] Figure 15This is a diagram illustrating the backoff process when the bandwidth of the BSS operation channel according to an embodiment of the present disclosure is 320 MHz.

[0034] Figure 16 This is a diagram illustrating the overlapping of different BSS operation channels according to one embodiment of the present disclosure.

[0035] Figure 17 This is a diagram illustrating the process by which an AP negotiates a non-primary channel access procedure with another AP according to one embodiment of the present disclosure. Detailed Implementation

[0036] In the following, embodiments according to this disclosure will be described in detail with reference to the accompanying drawings. The detailed description disclosed with reference to the drawings is intended to describe exemplary embodiments of this disclosure and not to represent the only embodiments in which this disclosure can be implemented. The following detailed description includes specific details to provide a complete understanding of this disclosure. However, those skilled in the art will recognize that this disclosure can be implemented without these specific details.

[0037] In some cases, known structures and devices may be omitted, or they may be shown in block diagram form based on the core functions of each structure and device in order to prevent ambiguity in the concepts of this disclosure.

[0038] In this disclosure, when an element is referred to as “connected,” “combined,” or “linked” to another element, it can include both indirect and direct connections between the two elements. Furthermore, in this disclosure, the terms “comprising” or “having” specify the presence of the mentioned features, steps, operations, components, and / or elements, but do not exclude the presence or addition of one or more other features, stages, operations, components, elements, and / or groups thereof.

[0039] In this disclosure, terms such as "first" and "second" are used only to distinguish one element from another and are not used to limit the elements. Unless otherwise stated, they do not limit the order or importance of the elements. Therefore, within the scope of this disclosure, a first element in one embodiment may be referred to as a second element in another embodiment, and similarly, a second element in one embodiment may be referred to as a first element in another embodiment.

[0040] The terminology used in this disclosure is for the purpose of describing particular embodiments and not for limiting the claims. As used in the description of embodiments and the appended claims, the singular form is intended to include the plural form unless the context clearly indicates otherwise. The term “and / or” as used in this disclosure may refer to one of the associated enumerations, or is intended to refer to and include any and all possible combinations of two or more of them. Furthermore, unless otherwise stated, the “ / ” between words in this disclosure has the same meaning as “and / or”.

[0041] The examples disclosed herein can be applied to various wireless communication systems. For example, the examples disclosed herein can be applied to wireless LAN systems. For example, the examples disclosed herein can be applied to wireless LANs based on the IEEE 802.11a / g / n / ac / ax standards. Furthermore, the examples disclosed herein can be applied to wireless LANs based on the newly proposed IEEE 802.11be (or EHT) standard. The examples disclosed herein can be applied to wireless LANs based on the IEEE 802.11be version 2 standard, corresponding to the additional enhancements of the IEEE 802.11be version 1 standard. Additionally, the examples disclosed herein can be applied to wireless LANs based on next-generation standards following IEEE 802.11be. Furthermore, the examples disclosed herein can be applied to cellular wireless communication systems. For example, it can be applied to cellular wireless communication systems based on 3GPP standards using Long Term Evolution (LTE) technology and 5G New Radio (NR) technology.

[0042] The technical features that can be applied to examples of this disclosure will be described below.

[0043] Figure 1 A block diagram illustrating a wireless communication device according to an embodiment of the present disclosure is shown.

[0044] Figure 1 The first device 100 and the second device 200 illustrated herein can be replaced by various terms such as terminal, wireless device, wireless transceiver unit (WTRU), user equipment (UE), mobile station (MS), user terminal (UT), mobile subscriber station (MSS), mobile subscriber unit (MSU), subscriber station (SS), advanced mobile station (AMS), wireless terminal (WT), or simply user. Furthermore, the first device 100 and the second device 200 include access point (AP), base station (BS), fixed station, node B, base transceiver system (BTS), and network. It can be replaced by various terms such as artificial intelligence (AI) system, roadside unit (RSU), repeater, router, relay, and gateway.

[0045] Figure 1 The devices 100 and 200 illustrated herein may be referred to as stations (STAs). For example, Figure 1The devices 100 and 200 illustrated herein may be referred to by various terms such as transmitting device, receiving device, transmitting STA, and receiving STA. For example, STA 110 and 200 may perform an access point (AP) role or a non-AP role. That is, in this disclosure, STA 110 and 200 may perform AP and / or non-AP functions. When STA 110 and 200 perform AP functions, they may simply be referred to as APs, and when STA 110 and 200 perform non-AP functions, they may simply be referred to as STAs. Alternatively, in this disclosure, AP may also be referred to as AP STA.

[0046] Reference Figure 1 The first device 100 and the second device 200 can transmit and receive radio signals via various wireless LAN technologies (e.g., IEEE 802.11 series). The first device 100 and the second device 200 may include interfaces for the Media Access Control (MAC) layer and Physical Layer (PHY) conforming to the IEEE 802.11 standard.

[0047] In addition to wireless LAN technology, the first device 100 and the second device 200 can also support various communication standards (e.g., 3GPP LTE series, 5G NR series standards, etc.). Furthermore, the devices disclosed herein can be implemented in various devices such as mobile phones, vehicles, personal computers, augmented reality (AR) devices, and virtual reality (VR) devices. Additionally, the STA of this specification can support various communication services such as voice calls, video calls, data communication, autonomous driving, machine-type communication (MTC), machine-to-machine (M2M), device-to-device (D2D), and IoT (Internet of Things).

[0048] The first device 100 may include one or more processors 102 and one or more memories 104, and may additionally include one or more transceivers 106 and / or one or more antennas 108. The processors 102 may control the memories 104 and / or the transceivers 106, and may be configured to implement the descriptions, functions, processes, suggestions, methods, and / or operation flowcharts included in this disclosure. For example, the processor 102 may transmit a wireless signal including the first information / signal via the transceivers 106 after generating first information / signal by processing information in the memories 104. Additionally, the processor 102 may receive a wireless signal including second information / signal via the transceivers 106, and then store information obtained through signal processing of the second information / signal in the memories 104. The memories 104 may be connected to the processor 102 and may store various information related to the operation of the processor 102. For example, the memories 104 may store software code including instructions for performing all or part of the processing controlled by the processor 102 or for performing the descriptions, functions, processes, suggestions, methods, and / or operation flowcharts included in this disclosure. Here, processor 102 and memory 104 may be part of a communication modem / circuit / chip designed to implement wireless LAN technology (e.g., IEEE 802.11 series). Transceiver 106 may be connected to processor 102 and may transmit and / or receive wireless signals via one or more antennas 108. Transceiver 106 may include a transmitter and / or a receiver. Transceiver 106 may be used with an RF (radio frequency) unit. In this disclosure, wireless device may refer to a communication modem / circuit / chip.

[0049] The second device 200 may include one or more processors 202 and one or more memories 204, and may additionally include one or more transceivers 206 and / or one or more antennas 208. The processors 202 may control the memories 204 and / or the transceivers 206, and may be configured to implement the descriptions, functions, processes, suggestions, methods, and / or operation flowcharts included in this disclosure. For example, the processors 202 may generate third information / signals by processing information in the memories 204, and then transmit a wireless signal including the third information / signals via the transceivers 206. Additionally, the processors 202 may receive wireless signals including fourth information / signals via the transceivers 206, and then store information obtained through signal processing of the fourth information / signals in the memories 204. The memories 204 may be connected to the processors 202 and may store various information related to the operation of the processors 202. For example, the memories 204 may store software code including instructions for performing all or part of the processing controlled by the processors 202 or for performing the descriptions, functions, processes, suggestions, methods, and / or operation flowcharts included in this disclosure. Here, processor 202 and memory 204 may be part of a communication modem / circuit / chip designed to implement wireless LAN technology (e.g., IEEE 802.11 series). Transceiver 206 may be connected to processor 202 and may transmit and / or receive wireless signals via one or more antennas 208. Transceiver 206 may include a transmitter and / or a receiver. Transceiver 206 may be used with an RF unit. In this disclosure, apparatus may refer to a communication modem / circuit / chip.

[0050] The hardware elements of devices 100 and 200 will be described in more detail below. Not limited thereto, one or more protocol layers may be implemented by one or more processors 102 and 202. For example, one or more processors 102 and 202 may implement one or more layers (e.g., functional layers such as PHY and MAC). One or more processors 102 and 202 may generate one or more PDUs (Protocol Data Units) and / or one or more SDUs (Service Data Units) according to the descriptions, functions, processes, suggestions, methods, and / or operation flowcharts disclosed in this disclosure. One or more processors 102 and 202 may generate messages, control information, data, or information according to the descriptions, functions, processes, suggestions, methods, and / or operation flowcharts disclosed in this disclosure. One or more processors 102 and 202 may generate signals (e.g., baseband signals) including PDUs, SDUs, messages, control information, data, or information according to the functions, processes, suggestions, and / or methods disclosed in this disclosure to provide them to one or more transceivers 106 and 206. One or more processors 102, 202 may receive signals (e.g., baseband signals) from one or more transceivers 106, 206 and obtain PDUs, SDUs, messages, control information, data or information, in accordance with the description, functions, processes, suggestions, methods and / or operation flowcharts included in this disclosure.

[0051] One or more processors 102, 202 may be referred to as controllers, microcontrollers, microprocessors, or microcomputers. One or more processors 102, 202 may be implemented by hardware, firmware, software, or a combination thereof. For example, one or more ASICs (Application-Specific Integrated Circuits), one or more DSPs (Digital Signal Processors), one or more DSPDs (Digital Signal Processing Devices), one or more PLDs (Programmable Logic Devices), or one or more FPGAs (Field-Programmable Gate Arrays) may be included in one or more processors 102, 202. The descriptions, functions, processes, suggestions, methods, and / or operation flowcharts included in this disclosure may be implemented using firmware or software, and the firmware or software may be implemented to include modules, processes, functions, etc. Firmware or software configured to execute the descriptions, functions, processes, suggestions, methods, and / or operation flowcharts included in this disclosure may be included in one or more processors 102, 202, or may be stored in one or more memories 104, 204 and driven by one or more processors 102, 202. The descriptions, functions, processes, suggestions, methods and / or operation flowcharts included in this disclosure may be implemented using firmware or software in the form of code, instructions and / or instruction sets.

[0052] One or more memories 104, 204 may be connected to one or more processors 102, 202 and may store data, signals, messages, information, programs, code, instructions, and / or commands in various forms. One or more memories 104, 204 may be configured with ROM, RAM, EPROM, flash memory, hard disk drive, registers, cache memory, computer-readable storage media, and / or combinations thereof. One or more memories 104, 204 may be located internally and / or externally to one or more processors 102, 202. Furthermore, one or more memories 104, 204 may be connected to one or more processors 102, 202 via various technologies such as wired or wireless connections.

[0053] One or more transceivers 106, 206 can transmit user data, control information, wireless signals / channels, etc., mentioned in the methods and / or operation flowcharts of this disclosure to one or more other devices. One or more transceivers 106, 206 can receive user data, control information, wireless signals / channels, etc., mentioned in the descriptions, functions, processes, suggestions, methods, and / or operation flowcharts included in this disclosure from one or more other devices. For example, one or more transceivers 106, 206 can be connected to one or more processors 102, 202 and can transmit and receive wireless signals. For example, one or more processors 102, 202 can control one or more transceivers 106, 206 to transmit user data, control information, or wireless signals to one or more other devices. Additionally, one or more processors 102, 202 can control one or more transceivers 106, 206 to receive user data, control information, or wireless signals from one or more other devices. Additionally, one or more transceivers 106, 206 may be connected to one or more antennas 108, 208, and one or more transceivers 106, 206 may be configured to transmit and receive user data, control information, wireless signals / channels, etc., mentioned in the descriptions, functions, processes, suggestions, methods, and / or operation flowcharts included in this disclosure, via one or more antennas 108, 208. In this disclosure, one or more antennas may be multiple physical antennas or multiple logical antennas (e.g., antenna ports). One or more transceivers 106, 206 may convert received wireless signals / channels, etc., from RF band signals into baseband signals for processing using one or more processors 102, 202. One or more transceivers 106, 206 may convert user data, control information, wireless signals / channels, etc., processed using one or more processors 102, 202, from baseband signals into RF band signals. Therefore, one or more transceivers 106, 206 may include (analog) oscillators and / or filters.

[0054] For example, one of STAs 100 and 200 can perform the expected operation of an AP, and the other of STAs 100 and 200 can perform the expected operation of a non-AP STA. For example, Figure 1 Transceivers 106 and 206 can perform transmission and reception operations of signals (e.g., packet or physical layer protocol data units (PPDUs) conforming to IEEE 802.11a / b / g / n / ac / ax / be / bn). Additionally, in this disclosure, the various STAs can generate transmit / receive signals or perform data processing or calculations on the transmit / receive signals in advance by [the relevant entity / component]. Figure 1Processors 102 and 202 perform the following operations: For example, examples of generating transmit / receive signals or performing data processing or computations on transmit / receive signals in advance may include: 1) determining / acquiring / configuring / computing / decoding / encoding bit information of fields (signals (SIG), short training field (STF), long training field (LTF), data, etc.) included in the PPDU; 2) determining / configuring / acquiring time or frequency resources (e.g., subcarrier resources) for the fields (SIG, STF, LTF, data, etc.) included in the PPDU; 3) determining / configuring / acquiring specific sequences (e.g., pilot sequences, STF / LTF sequences, additional sequences applied to SIG) for the fields (SIG, STF, LTF, data, etc.) included in the PPDU action; 4) power control operations and / or power saving operations applied to the STA; 5) operations related to determining / acquiring / configuring / computing / decoding / encoding of the ACK signal. Additionally, in the example below, various information used by different STAs to determine / acquire / configure / calculate / decode / encode transmitted and received signals (e.g., information related to fields / subfields / control fields / parameters / power, etc.) can be stored. Figure 1 In memory 104 and 204.

[0055] In the following text, downlink (DL) can refer to a link used for communication from an AP STA to a non-AP STA, and DL PPDU / packets / signals can be sent and received via DL. In DL communication, the transmitter can be part of an AP STA, and the receiver can be part of a non-AP STA. Uplink (UL) can refer to a link used for communication from a non-AP STA to an AP STA, and UL PPDU / packets / signals can be sent and received via UL. In UL communication, the transmitter can be part of a non-AP STA, and the receiver can be part of an AP STA.

[0056] Figure 2 This is a diagram illustrating an exemplary structure of a wireless LAN system to which this disclosure can be applied.

[0057] A wireless LAN system can be structured by multiple components. These components interact to provide STA mobility support that is transparent to upper layers. The Basic Service Set (BSS) corresponds to the basic building blocks of a wireless LAN. Figure 2 An example is shown where there are two BSSs (BSS1 and BSS2), and two STAs included as members of each BSS (STA1 and STA2 are included in BSS1, and STA3 and STA4 are included in BSS2). Figure 2The ellipse representing the BSS can also be interpreted as representing the coverage area within the corresponding BSS where STAs maintain communication. This area can be called the Basic Service Area (BSA). When a STA moves outside the BSA, it cannot communicate directly with other STAs within the BSA.

[0058] If we do not consider Figure 2 The DS shown in the diagram represents the most basic BSS type in a wireless LAN: the Independent BSS (IBSS). For example, an IBSS can have a minimal form containing only two STAs. For instance, assuming other components are omitted, BSS1 containing only STA1 and STA2, or BSS2 containing only STA3 and STA4, can respectively correspond to representative examples of IBSS. This configuration is possible when STAs can communicate directly without an AP. Furthermore, in this type of wireless LAN, it is not pre-configured but can be configured as needed, and this can be called an ad-hoc network. Since an IBSS does not include an AP, there is no centralized management entity. That is, in an IBSS, STAs are managed in a distributed manner. In an IBSS, all STAs can consist of mobile STAs and are not allowed to access the Distributed System (DS), thus forming a self-contained network.

[0059] Membership of an STA in a BSS can be dynamically changed by opening or closing an STA, or by entering or leaving a BSS zone. To become a member of a BSS, an STA can join the BSS using a synchronization process. To access all services of the BSS infrastructure, an STA must be associated with the BSS. This association can be dynamically established and may include the use of Distributed System Services (DSS).

[0060] Direct STA-to-STA distance in a wireless LAN may be limited by PHY performance. In some cases, this distance limitation may be sufficient, but in others, longer distances between STAs may be required for communication. Distributed systems (DS) can be configured to support extended coverage.

[0061] DS refers to the structure of BSS interconnection. Specifically, such as... Figure 2As shown, a BSS can exist as an extension of a network composed of multiple BSSs. A DS is a logical concept and can be specified through the characteristics of the Distributed System Medium (DSM). At this point, the Wireless Medium (WM) and the DSM can be logically separated. Each logical medium is used for a different purpose and by different components. These media are not limited to being the same, nor are they limited to being different. In this way, the flexibility of a wireless LAN architecture (DS architecture or other network architectures) can be interpreted as multiple media being logically different. That is, a wireless LAN architecture can be implemented in various ways, and the corresponding wireless LAN architecture can be independently specified by the physical characteristics of each implementation.

[0062] The DS can support mobile devices by providing seamless integration of multiple BSSs and offering the logical services necessary for addressing to the destination. Additionally, the DS may include a component called a portal, which acts as a bridge between the wireless LAN and other networks, such as IEEE 802.X.

[0063] AP enables access to DS via WM for associated non-AP STAs, and refers to entities that also have STA functionality. Data movement between BSS and DS can be performed through AP. For example, Figure 2 STA2 and STA3, shown in the diagram, have the functionality of STAs and provide the ability for associated non-AP STAs (STA1 and STA4) to access the DS. Furthermore, since all APs essentially correspond to STAs, all APs are addressable entities. The address used by an AP for communication on the WM is not necessarily the same as the address used by the AP for communication on the DSM. A BSS consisting of APs and one or more STAs can be referred to as an infrastructure BSS.

[0064] Data sent from one of the STAs associated with the AP to the corresponding STA address of the AP can always be received on an uncontrolled port and can be processed by the IEEE 802.1X port access entity. Alternatively, when the controlled port is authenticated, the transmitted data (or frames) can be delivered to the DS.

[0065] In addition to the DS structure described above, Extended Service Sets (ESS) can also be configured to provide wide coverage.

[0066] An ESS (Service Set Identity) refers to a network of arbitrary size and complexity consisting of DS (Service Controller) and BSS (Service Set Service). An ESS can correspond to a set of BSSs connected to a DS. However, an ESS does not include the DS. An ESS network is characterized as an IBSS (Integrated Service Set Service) within the Logical Link Control (LLC) layer. STAs included in an ESS can communicate with each other, and a moving STA can transparently move from one BSS to another (within the same ESS) to the LLC. APs included in an ESS can have the same Service Set Identity (SSID). The SSID is distinguished from the BSSID, which serves as the identifier for the BSS.

[0067] Wireless LAN systems make no assumptions about the relative physical locations of BSSs, and all of the following forms are possible: BSSs can partially overlap, a form commonly used to provide continuous coverage. Additionally, BSSs may not be physically connected, and logically, there is no limit to the distance between BSSs. Furthermore, BSSs can be physically located in the same location, which can be used to provide redundancy. Additionally, one (or more) IBSS or ESS networks can physically exist in the same space as one (or more) ESS networks. This can correspond to the form of ESS networks when an ad hoc network operates in a location where an ESS network exists, when physically overlapping wireless networks are configured by different organizations, or when two or more different access and security policies are required in the same location, etc.

[0068] Figure 3 This is a diagram used to illustrate the link establishment process that can be applied to this disclosure.

[0069] In order for a STA to establish a link with the network and send / receive data, it first discovers the network, performs authentication, establishes an association, and performs authentication processing for security. The link establishment process can also be called session initiation processing or session establishment processing. Furthermore, the discovery, authentication, association, and security establishment processes of the link establishment process can be collectively referred to as association processing.

[0070] In step S310, the STA can perform a network discovery operation. The network discovery operation may include a scanning operation by the STA. That is, in order for the STA to access a network, it needs to find networks it can participate in. The STA should identify compatible networks before participating in a wireless network, and the process of identifying networks existing in a specific area is called scanning.

[0071] Scanning schemes include active scanning and passive scanning. Figure 3An exemplary network discovery operation including active scanning processing is illustrated. In active scanning, the STA performing the scan sends a probe request frame to discover which APs are present around it as the channel moves and awaits a response. The responder sends a probe response frame as a response to the probe request frame to the STA that sent the probe request frame. Here, the responder may be the STA that last sent a beacon frame in the BSS of the channel being scanned. In the BSS, the AP becomes the responder because it sends a beacon frame, and in the IBSS, the STAs in the IBSS rotate to send beacon frames, so the responder is not constant. For example, an STA that sends a probe request frame on channel 1 and receives a probe response frame on channel 1 may store the BSS-related information included in the received probe response frame and may move to the next channel (e.g., channel 2) and perform a scan in the same manner (i.e., sending and receiving probe requests / responses on channel 2).

[0072] Although not in Figure 3 As shown, scanning can be performed passively. In passive scanning, the STA performing the scan waits for beacon frames while moving through the channel. Beacon frames are one of the management frames defined in IEEE 802.11 and are sent periodically to notify of the existence of a wireless network and allow the STA performing the scan to find and participate in the wireless network. In the BSS, the AP periodically sends beacon frames, and in the IBSS, the STA within the IBSS rotates to send beacon frames. When the STA performing the scan receives a beacon frame, it stores the BSS information included in the beacon frame and records the beacon frame information for each channel while moving to another channel. The STA receiving the beacon frame can store the BSS-related information included in the received beacon frame, move to the next channel, and perform scanning in the next channel in the same manner. Comparing active and passive scanning, active scanning has the advantages of less latency and less power consumption.

[0073] After the STA discovers the network, an authentication process can be performed in step S320. To clearly distinguish it from the security establishment operation in step S340, which will be described later, this authentication process can be referred to as the first authentication process.

[0074] The authentication process includes the following steps: the STA sends an authentication request frame to the AP, and in response, the AP sends an authentication response frame to the STA. The authentication frame used for the authentication request / response corresponds to the management frame.

[0075] An authentication frame includes the authentication algorithm number, authentication transaction sequence number, status code, challenge text, robust security network (RSN), and finite circular group. These correspond to some examples of information that can be included in the authentication request / response frame and can be replaced with other information, or additional information may be included.

[0076] A STA can send an authentication request frame to an AP. The AP can determine whether to allow the corresponding STA's authentication based on the information included in the received authentication request frame. The AP can then provide the STA with the authentication processing result via an authentication response frame.

[0077] After the STA is successfully authenticated, the association process can be performed in step S330. The association process includes the following steps: the STA sends an association request frame to the AP, and in response, the AP sends an association response frame to the STA.

[0078] For example, an association request frame may include information related to various capabilities, beacon listening intervals, service set identifiers (SSIDs), supported rates, supported channels, RSNs, mobile domains, supported operation classes, traffic indication mapping broadcast requests (TIM broadcast requests), interoperability capabilities, etc. Similarly, an association response frame may include information related to various capabilities, status codes, association IDs (AIDs), supported rates, enhanced distributed channel access (EDCA) parameter sets, received channel power indicators (RCPIs), received signal-to-noise ratio indicators (RSNIs), mobile domains, timeout intervals (e.g., association recovery time), overlapping BSS scan parameters, TIM broadcast responses, quality of service (QoS) mappings, etc. These correspond to some examples of information that can be included in association request / response frames and may be replaced with other information, or additional information may be included.

[0079] After the STA successfully associates with the network, a security establishment process can be performed in step S340. The security establishment process in step S340 can be referred to as the authentication process via a Robust Secure Network Association (RSNA) request / response, the authentication process in step S320 is referred to as the first authentication process, and the security establishment process in step S340 can also be simply referred to as the authentication process.

[0080] The secure establishment process in step S340 may include, for example, the process of establishing a private key using a four-way handshake via Extensible Authentication Protocol (EAPOL) frames over the LAN. Alternatively, the secure establishment process may be performed according to a security scheme not defined in the IEEE 802.11 standard.

[0081] Figure 4 This is a diagram used to illustrate the backoff processing that can be applied to this disclosure.

[0082] In wireless LAN systems, the basic access mechanism for Media Access Control (MAC) is Carrier Sensing Multiple Access with Collision Avoidance (CSMA / CA). Also known as the Distributed Coordination Function (DCF) of IEEE 802.11 MAC, CSMA / CA essentially employs a "listen-before-talk" access mechanism. Under this type of access mechanism, before commencing transmission, the AP and / or STA can perform explicit channel assessment (CCA) of the sensing radio channel or medium during a predetermined time interval (e.g., the DCF inter-frame interval (DIFS)). As a result of the sensing, if it is determined that the medium is idle, frame transmission begins via the corresponding medium. Conversely, if the medium is detected to be occupied or busy, the corresponding AP and / or STA does not begin its own transmission and can set a delay period for medium access (e.g., a random backoff period) and attempt frame transmission after waiting. By applying a random backoff period, collisions can be minimized because multiple STAs are expected to attempt frame transmission after waiting for different time periods.

[0083] In addition, the IEEE 802.11 MAC protocol provides a Hybrid Coordination Function (HCF). HCF is based on DCF and Point Coordination Function (PCF). PCF is a polling-based synchronous access method, meaning that all receiving APs and / or STAs periodically poll to receive data frames. Furthermore, HCF includes Enhanced Distributed Channel Access (EDCA) and HCF Control Channel Access (HCCA). EDCA is a contention-based access method that provides data frames to multiple users, while HCCA uses a non-contention-based channel access method that utilizes a polling mechanism. Additionally, HCF includes a media access mechanism for improving the QoS (Quality of Service) of wireless LANs and can transmit QoS data during contention periods (CP) and contention-free periods (CFP).

[0084] Reference Figure 4 This section describes the operation based on a random backoff period. When an occupied / busy medium becomes idle, multiple STAs can attempt to transmit data (or frames). As a method to minimize collisions, each STA can individually select a random backoff count and attempt to transmit after waiting for the corresponding time slot. The random backoff count has a pseudo-random integer value and can be determined as one of the values ​​ranging from 0 to CW. Here, CW is the contention window parameter value. The CW parameter is assigned an initial value of CWmin, but can take a value twice as large as in the event of transmission failure (e.g., when no ACK is received for the transmitted frame). When the CW parameter value reaches CWmax, data transmission can be attempted while maintaining the CWmax value until successful data transmission, and when successful, the CWmin value is reset. The values ​​of CW, CWmin, and CWmax are preferably set to 2.n -1 (n=0, 1, 2, ...).

[0085] When random backoff processing begins, the STA continuously monitors the medium during the backoff time slot countdown based on the determined backoff count value. When monitoring the medium for occupancy, it stops the countdown and waits, and restarts the remainder of the countdown when the medium becomes idle.

[0086] exist Figure 4 In the example, when the packet to be sent arrives at STA 3's MAC, STA 3 can send the frame immediately after confirming that the medium has been idle for up to DIFS. The remaining STAs monitor and wait for the medium to be occupied / busy. Meanwhile, the data to be sent can also occur in each of STA 1, STA 2, and STA 5, and when the medium is detected as idle, each STA waits for up to DIFS, and then performs a countdown for the backoff slot based on a random backoff count value chosen by each STA. Assume STA 2 chooses the minimum backoff count value, and STA 1 chooses the maximum backoff count value. That is, the example illustrates the case where STA 5's remaining backoff time is shorter than STA 1's remaining backoff time when STA 2 completes its backoff count and begins frame transmission. STA 1 and STA 5 temporarily stop the countdown and wait while STA 2 occupies the medium. When STA 2's occupancy ends and the medium becomes idle again, STA 1 and STA 5 wait for DIFS and restart the stopped backoff count. In other words, frame transmission can begin after a countdown for the remaining backoff slot based on the remaining backoff time. Since STA5 has a shorter remaining backoff time than STA1, STA5 begins frame transmission. Data to be transmitted can also occur in STA4 while STA2 is occupying the medium. From STA4's perspective, when the medium becomes idle, STA4 can wait for DIFS, then execute a countdown based on a random backoff count value selected by STA4, and begin transmitting frames. Figure 4 The example illustrates a scenario where the remaining backoff time of STA5 accidentally conflicts with the random backoff count value of STA4. In this case, a collision may occur between STA4 and STA5. When a collision occurs, neither STA4 nor STA5 receives an ACK, so data transmission fails. In this situation, STA4 and STA5 can double the CW value, select a random backoff count value, and begin a countdown. While the medium is occupied due to the transmissions of STA4 and STA5, STA1 waits; when the medium becomes idle, STA1 waits for DIFS, and then begins frame transmission after the remaining backoff time has elapsed.

[0087] As in Figure 4In the example, data frames are frames used to send data forwarded to higher layers and can be sent after a backoff performed after DIFS, starting from when the medium becomes idle. Additionally, management frames are frames used to exchange management information that has not been forwarded to higher layers and are sent after a backoff performed after an IFS such as DIFS or Point Coordination Function IFS (PIFS). Subtypes of management frames include beacons, association requests / responses, reassociation requests / responses, probe requests / responses, authentication requests / responses, etc. Control frames are frames used to control access to the medium. Subtypes of control frames include request-to-transmit (RTS), clear-to-transmit (CTS), acknowledgment (ACK), power-saving polling (PS-Poll), block ACK (BlockAck), block ACK request (BlockACKReq), empty data packet announcement (NDP announcement), and triggering, etc. If a control frame is not a response frame to the previous frame, it is sent after a backoff performed after DIFS; if it is a response frame to the previous frame, it is sent without a backoff performed after short IFS (SIFS). The type and subtype of a frame can be identified by the type field and subtype field in the Frame Control (FC) field.

[0088] The Quality of Service (QoS) ST can perform a backoff following the Arbitration IFS (AIFS) for the Access Class (AC) to which the frame belongs (i.e., AIFS where i is a value determined by the AC) before the frame can be transmitted. Here, the frame that can use AIFS can be a data frame, management frame, or control frame, rather than a response frame.

[0089] Figure 5 This is a diagram illustrating the CSMA / CA-based frame transmission operation that can be applied to this disclosure.

[0090] As mentioned above, in addition to physical carrier sensing of the medium directly sensed by the STA, the CSMA / CA mechanism also includes virtual carrier sensing. Virtual carrier sensing aims to compensate for problems such as hidden node issues that may occur during medium access. For virtual carrier sensing, the STA's MAC can use the Network Allocation Vector (NAV). The NAV is a value that indicates to other STAs the remaining time until the medium is available for current use or for STAs authorized to use the medium. Therefore, a value set to NAV corresponds to the period during which the STA sending the frame plans to use the medium, and during the corresponding period, STAs receiving the NAV value are prohibited from accessing the medium. For example, the NAV can be configured based on the value of the "Duration" field in the frame's MAC header.

[0091] exist Figure 5 In the example, assume that STA1 is intended to send data to STA2, and STA3 is located in a position that allows it to eavesdrop on some or all of the frames being sent and received between STA1 and STA2.

[0092] To reduce the likelihood of transmission conflicts among multiple STAs in CSMA / CA-based frame transmission operations, a mechanism using RTS / CTS frames can be applied. Figure 5 In the example, when STA1 is transmitting, as a result of carrier sensing by STA3, it can be determined that the medium is in an idle state. That is, STA1 can correspond to a hidden node with respect to STA3. Alternatively, in Figure 5 In the example, it can be determined that while STA2 is transmitting, the carrier sensing result medium of STA3 is in an idle state. That is, STA2 can correspond to a hidden node with respect to STA3. By exchanging RTS / CTS frames before performing data transmission and reception between STA1 and STA2, STAs outside the transmission range of either STA1 or STA2, or STAs outside the carrier sensing range of transmissions from STA1 or STA3, can avoid attempting to occupy the channel during data transmission and reception between STA1 and STA2.

[0093] Specifically, STA1 can determine whether a channel is in use through carrier sensing. Regarding physical carrier sensing, STA1 can determine the channel occupancy / idle status based on the energy level or signal correlation detected in the channel. Alternatively, regarding virtual carrier sensing, STA1 can use a Network Allocation Vector (NAV) timer to determine the channel occupancy status.

[0094] When the channel is idle during DIFS, STA1 can send an RTS frame to STA2 after performing backoff. When STA2 receives the RTS frame, STA2 can send a CTS frame to STA1 after SIFS as a response to the RTS frame.

[0095] If STA3 cannot eavesdrop on CTS frames from STA2 but can eavesdrop on RTS frames from STA1, STA3 can use the duration information included in the RTS frame to set the NAV timer for the subsequent consecutive frame transmission period (e.g., SIFS+CTS frame+SIFS+data frame+SIFS+ACK frame). Alternatively, if STA3 can eavesdrop on CTS frames from STA2, STA3 can also use the duration information included in the CTS frame to set the NAV timer for the subsequent consecutive frame transmission period (e.g., SIFS+data frame+SIFS+ACK frame) even though STA3 cannot eavesdrop on RTS frames from STA1. That is, if STA3 can eavesdrop on one or more RTS frames or CTS frames from STA1 or STA2, STA3 can set the NAV accordingly. When STA3 receives a new frame before the NAV timer expires, STA3 can use the duration information included in the new frame to update the NAV timer. STA3 does not attempt channel access until the NAV timer expires.

[0096] When STA1 receives a CTS frame from STA2, STA1 can send a data frame to STA2 after SIFS, starting from the time point when the CTS frame reception is complete. When STA2 successfully receives the data frame, STA2 can send an ACK frame to STA1 after SIFS as a response to the data frame. When the NAV timer expires, STA3 can determine whether the channel is being used through carrier sensing. If STA3 determines that the channel is not being used by other terminals during the DIFS period after the NAV timer expires, STA3 can attempt channel access after the contention window (CW) for random backoff has expired.

[0097] Figure 6 This is a diagram illustrating an example of a frame structure that can be used in a WLAN system to which this disclosure may be applied.

[0098] Using instructions or primitives (meaning a set of instructions or parameters) from the MAC layer, the PHY layer can prepare the MAC PDU (MPDU) to be transmitted. For example, when the PHY layer receives a command from the MAC layer requesting the start of transmission, it switches to transmit mode, configures the information (e.g., data) provided by the MAC layer in the form of a frame, and transmits it. Additionally, when the PHY layer detects a valid preamble in a received frame, it monitors the preamble header and sends a command to the MAC layer notifying the PHY layer of the start of reception.

[0099] In this way, information transmission / reception in a wireless LAN system is performed in the form of frames, and for this purpose, the PHY layer Protocol Data Unit (PPDU) format is defined.

[0100] A basic PPDU can include a Short Training Field (STF), a Long Training Field (LTF), a Signal (SIG) field, and a Data field. The most basic PPDU format (e.g., Figure 7 The non-HT (High Throughput) fields shown can consist solely of a Traditional-STF (L-STF), Traditional-LTF (L-LTF), Traditional-SIG (L-SIG) field, and a data field. Additionally, depending on the PPDU format type (e.g., HT mixed format PPDU, HT green format PPDU, VHT (Very High Throughput) PPDU, etc.), additional (or different types) RL-SIG, U-SIG, non-traditional SIG fields, non-traditional STF, non-traditional LTF (i.e., xx-SIG, xx-STF, xx-LTF (e.g., xx is HT, VHT, HE, EHT, etc.)) can be included between the L-SIG field and the data field.

[0101] STF is a signal used for signal detection, automatic gain control (AGC), diversity selection, precise time synchronization, etc., while LTF is a signal used for channel estimation and frequency error estimation. STF and LTF can be referred to as signals used for synchronization and channel estimation in the OFDM physical layer.

[0102] The SIG field can include various information related to PPDU transmission and reception. For example, the L-SIG field consists of 24 bits and can include a 4-bit rate field, a 1-bit reserved bit, a 12-bit length field, a 1-bit parity field, and a 6-bit tail field. The RATE field can include information about the modulation and coding rate of the data. For example, the 12-bit length field can include information about the length or duration of the PPDU. For example, the value of the 12-bit length field can be determined based on the type of PPDU. For example, for non-HT, HT, VHT, or EHT PPDUs, the value of the length field can be determined to be a multiple of 3. For example, for HEPPDUs, the value of the length field can be determined to be a multiple of 3+1 or 3+2.

[0103] The data field may include a service field, a physical layer service data unit (PSDU), and a PPDU tail bit, and may also include padding bits if necessary. Some bits of the service field can be used for synchronization of the descrambler at the receiver. The PSDU corresponds to the MAC PDU defined in the MAC layer and may include data generated / used in the upper layer. The PPDU tail bit can be used to return the encoder to a 0 state. Padding bits can be used to adjust the length of the data field by predetermined units.

[0104] MAC PDUs are defined according to various MAC frame formats, and a basic MAC frame consists of a MAC header, a frame body, and a Frame Check Sequence (FCS). MAC frames can be composed of MAC PDUs and transmitted / received via PSDUs in the data portion of the PPDU format.

[0105] The MAC header includes a frame control field, a duration / ID field, and an address field. The frame control field can include control information required for frame transmission / reception. The duration / ID field can be set to the time used to transmit the corresponding frame, etc. For details on the sequence control, QoS control, and HT control subfields of the MAC header, refer to the IEEE 802.11 standard document.

[0106] The Narrow Data PPDU (NDP) format refers to a PPDU format that does not include the data field. In other words, NDP is a frame format that includes the PPDU preamble of the general PPDU format (i.e., the L-STF, L-LTF, L-SIG fields and other non-traditional SIG, non-traditional STF, and non-traditional LTF (if present)) and does not include the remaining part (i.e., the data field).

[0107] Figure 7 This is a diagram illustrating an example of a PPDU as defined in the IEEE 802.11 standard of this disclosure.

[0108] Various types of PPDUs have been used in standards such as IEEE 802.11a / g / n / ac / ax. The basic PPDU format (IEEE 802.11a / g) includes L-LTF, L-STF, L-SIG, and a data field. The basic PPDU format can also be referred to as a non-HT PPDU format (such as...). Figure 7 (as shown in (a)).

[0109] Compared to the basic PPDU format, the HT PPDU format (IEEE 802.11n) additionally includes the HT-SIG, HT-STF, and HT-LFT fields. Figure 7 The HT PPDU format shown in (b) can be referred to as the HT hybrid format. Furthermore, an HT green format PPDU can be defined, and this corresponds to a format consisting of HT-GF-STF, HT-LTF1, HT-SIG, one or more HT-LTFs and data fields, excluding L-STF, L-LTF, and L-SIG (not shown).

[0110] Compared to the basic PPDU format, examples of the VHT PPDU format (IEEE 802.11ac) additionally include VHTSIG-A, VHT-STF, VHT-LTF, and VHT-SIG-B fields (such as...). Figure 7 (as shown in (c)).

[0111] Compared to the basic PPDU format, examples of the HE PPDU format (IEEE 802.11ax) additionally include repeated L-SIG (RL-SIG), HE-SIG-A, HE-SIG-B, HE-STF, HE-LTF, and Packet Extension (PE) fields (such as...). Figure 7 (as shown in (d)). Some fields can be excluded, or their lengths can vary depending on the detailed examples of the HE PPDU format. For example, the HE-SIG-B field is included in the HE PPDU format for multi-user (MU), but not in the HE PPDU format for single-user (SU). Furthermore, the HE-Trigger-Based (TB) PPDU format does not include HE-SIG-B, and the length of the HE-STF field can vary up to 8 μs. The Extended Range (HE ER) SU PPDU format does not include the HE-SIG-B field, and the length of the HE-SIG-A field can vary up to 16 μs. For example, RL-SIG can be configured to be the same as L-SIG. Based on the presence of RL-SIG, the receiving STA can determine whether the received PPDU is an HE PPDU or an EHT PPDU, which will be described later.

[0112] EHT PPDU format can include Figure 7 EHT MU (Multi-user) in (e) and Figure 7 The EHT TB (trigger-based) PPDU in (f). The EHT PPDU format is similar to the HE PPDU format in that it includes RL-SIG following L-SIG, but it can include U (generic)-SIG, EHT-SIG, EHT-STF and EHT-LTF following RL-SIG.

[0113] Figure 7 In (e), the EHT MU PPDU corresponds to a PPDU carrying one or more data (or PSDU) for one or more users. That is, the EHT MU PPDU can be used for both SU and MU transmissions. For example, the EHT MU PPDU can correspond to a PPDU for one or more receiving STAs.

[0114] Compared to EHT MU PPDU, Figure 7 In (f), the EHT-SIG is omitted from the EHT TB PPDU. The STA that receives the trigger for UL MU transmission (e.g., trigger frame or trigger response schedule (TRS)) can perform UL transmission based on the EHT TB PPDU format.

[0115] The L-STF, L-LTF, L-SIG, RL-SIG, U-SIG (general signal), and EHT-SIG fields can be encoded and modulated so that even conventional STAs can attempt demodulation and decoding, and can be mapped based on a determined subcarrier frequency interval (e.g., 312.5 kHz). These can be referred to as pre-EHT modulated fields. Next, the EHT-STF, EHT-LTF, data, and PE fields can be encoded and modulated for demodulation and decoding by an STA that has successfully decoded a non-conventional SIG (e.g., U-SIG and / or EHT-SIG) and obtained the information contained in that field, and can be mapped based on a determined subcarrier frequency interval (e.g., 78.125 kHz). These can be referred to as EHT modulated fields.

[0116] Similarly, in the HE PPDU format, the L-STF, L-LTF, L-SIG, RL-SIG, HE-SIG-A, and HE-SIG-B fields can be referred to as pre-HE modulation fields, and the HE-STF, HE-LTF, data, and PE fields can be referred to as HE modulation fields. Additionally, in the VHT PPDU format, the L-STF, L-LTF, L-SIG, and VHT-SIG-A fields can be referred to as non-VHT modulation fields, and the VHT STF, VHT-LTF, VHT-SIG-B, and data fields can be referred to as VHT modulation fields.

[0117] Included Figure 7 In the EHT PPDU format, U-SIG can be configured based on, for example, two symbols (e.g., two consecutive OFDM symbols). Each symbol used for U-SIG (e.g., an OFDM symbol) can have a duration of 4 μs, and U-SIG can have a total duration of 8 μs. Each symbol of U-SIG can be used to transmit 26 bits of information. For example, each symbol of U-SIG can be transmitted and received based on 52 data tones and 4 pilot tones.

[0118] U-SIGs can be constructed in 20 MHz units. For example, if an 80 MHz PPDU is constructed, U-SIGs can be replicated. That is, the same four U-SIGs can be included in an 80 MHz PPDU. PPDUs with bandwidths exceeding 80 MHz can include different U-SIGs.

[0119] For example, A uncoded bits can be sent via U-SIG. The first symbol of U-SIG (e.g., U-SIG-1 symbol) can send the first X bits of the total A bits, and the second symbol of U-SIG (e.g., U-SIG-2 symbol) can send the remaining Y bits of the total A bits. The A bits (e.g., 52 uncoded bits) can include a CRC field (e.g., a 4-bit field) and a tail field (e.g., a 6-bit field). For example, the tail field can be used to terminate the lattice structure of the convolutional decoder and can be set to 0.

[0120] Bit information sent via U-SIG can be divided into version-independent bits and version-dependent bits. For example, U-SIG can be included in... Figure 7 The new PPDU format (e.g., UHR PPDU format) not shown in the figure can be included in the format of the U-SIG field included in the EHTPPDU format and the format of the U-SIG field included in the UHR PPDU format. The version-independent bits can be the same, and some or all of the version-related bits can be different.

[0121] For example, the size of the version-independent bits in U-SIG can be fixed or variable. Version-independent bits can be assigned only to the U-SIG-1 symbol, or to both the U-SIG-1 and U-SIG-2 symbols. Version-independent and version-dependent bits can be referred to by various names, such as first control bit and second control bit.

[0122] For example, the version-independent bits of U-SIG may include a 3-bit Physical Layer Version Identifier (PHY Version Identifier), which can indicate the PHY version (e.g., EHT, UHR, etc.) of the transmitted / received PPDU. 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 is related to UL communication, and the second value is related to DL communication. The version-independent bits of U-SIG may include information about the length of the Transmission Opportunity (TXOP) and information about the BSS color ID.

[0123] For example, the version-related bits of U-SIG may include information that directly or indirectly indicates the type of PPDU (e.g., SU PPDU, MU PPDU, TB PPDU, etc.).

[0124] Information required for PPDU transmission and reception can be included in the U-SIG. For example, the U-SIG may also include information about bandwidth, information about the MCS technique applied to non-traditional SIGs (e.g., EHT-SIG or UHR-SIG), information indicating whether DCM (dual-carrier modulation) techniques (e.g., techniques used to achieve effects similar to frequency diversity by reusing the same signal on two subcarriers) are applied to non-traditional SIGs, information about the number of symbols used for non-traditional SIGs, and information about whether non-traditional SIGs are generated across the entire frequency band.

[0125] Some of the information required for PPDU transmission and reception may be included in U-SIG and / or non-traditional SIG (e.g., EHT-SIG or UHR-SIG). For example, information about the type of non-traditional LTF / STF (e.g., EHT-LTF / EHT-STF or UHR-LTF / UHR-STF), the length of the non-traditional LTF and the CP (cyclic prefix) length, the GI (guard interval) applicable to the non-traditional LTF, the preamble punching information applicable to the PPDU, and the resource unit (RU) allocation may be included only in U-SIG, only in non-traditional SIG, or may be indicated by a combination of information included in U-SIG and information included in non-traditional SIG.

[0126] Preamble puncturing can represent the transmission of a PPDU where no signal is present in one or more frequency units within the bandwidth of the PPDU. For example, the size of the frequency unit (or the resolution of the preamble puncturing) can be defined as 20 MHz, 40 MHz, etc. For example, preamble puncturing can be applied to PPDU bandwidths of a predetermined size or larger.

[0127] exist Figure 7 In the examples, non-traditional SIGs such as HE-SIG-B and EHT-SIG can include control information for receiving STAs. Non-traditional SIGs can be transmitted on at least one symbol, and a symbol can have a length of 4 μs. Information regarding the number of symbols used for EHT-SIGs can be included in previous SIGs (e.g., HE-SIG-A, U-SIG, etc.).

[0128] Non-traditional SIGs such as HE-SIG-B and EHT-SIG can include both public and user-specific fields. These public and user-specific fields can be encoded separately.

[0129] In some cases, the common field can be omitted. For example, in compressed mode using non-OFDMA (Orthogonal Frequency Division Multiple Access), the common field can be omitted, and multiple STAs can receive PPDUs (e.g., the data field of the PPDU) through the same frequency band. In uncompressed mode using OFDMA, multiple users can receive PPDUs (e.g., the data field of the PPDU) through different frequency bands.

[0130] The number of user-specific fields can be determined based on the number of users. A user block field can include up to two user fields. Each user field can be associated with either a MU-MIMO allocation or a non-MU-MIMO allocation.

[0131] The common fields may include CRC bits and a tail bit, where the length of the CRC bits can be determined to be 4 bits, and the length of the tail bit can be determined to be 6 bits and set to 000000. The common fields may include RU allocation information. RU allocation information may include information about the locations of RUs assigned to multiple users (i.e., multiple receiving STAs).

[0132] An RU can include multiple subcarriers (or tones). RUs can be used when transmitting signals to multiple STAs based on OFDMA technology. Additionally, RUs can be defined even when transmitting signals to a single STA. Resources can be allocated in units of RUs for non-traditional STFs, non-traditional LTFs, and data fields.

[0133] The appropriate RU size can be defined based on the PPDU bandwidth. RUs can be defined the same or different for the applied PPDU format (e.g., HEPPDU, EHT PPDU, UHR PPDU, etc.). For example, in the case of an 80 MHz PPDU, the RU layout for HEPPDU and EHT PPDU can be different. The appropriate RU size, number and location of RUs, DC (direct current) subcarrier locations and numbers, empty subcarrier locations and numbers, guard subcarrier locations and numbers, etc., for each PPDU bandwidth can be referred to as the tone scheme. For example, a tone scheme for high bandwidth can be defined as multiple iterations of a low-bandwidth tone scheme.

[0134] RUs of various sizes can be defined as 26-tone RUs, 52-tone RUs, 106-tone RUs, 242-tone RUs, 484-tone RUs, 996-tone RUs, 2×996-tone RUs, 3×996-tone RUs, etc. MRUs (Multiple RUs) differ from multiple individual RUs and correspond to a group of subcarriers composed of multiple RUs. For example, an MRU can be defined as 52+26 tones, 106+26 tones, 484+242 tones, 996+484 tones, 996+484+242 tones, 2×996+484 tones, 3×996 tones, or 3×996+484 tones. Furthermore, the multiple RUs constituting an MRU can be consecutive or non-consecutive in the frequency domain.

[0135] The specific size of the RU can be reduced or expanded. Therefore, the specific size of each RU in this disclosure (i.e., the number of corresponding tones) is not limiting but illustrative. In addition, in this disclosure, the number of RUs can vary depending on the RU size within a predetermined bandwidth (e.g., 20 MHz, 40 MHz, 80 MHz, 160 MHz, 320 MHz...).

[0136] Figure 7 The names of each field in the PPDU format are exemplary, and the scope of this disclosure is not limited to these names. Furthermore, the examples in this disclosure can be applied to… Figure 7 The PPDU format shown and based on Figure 7 A new PPDU format that excludes some fields and / or adds some fields, based on the PPDU format.

[0137] Channel access based on the main channel

[0138] Channel access in a wireless LAN system is performed based on the primary channel. For example, if the primary channel is idle and the backoff counter (BC) expires, the STA can transmit frames on a channel that includes both the primary channel and an idle secondary channel. Therefore, all STAs preferably perform CCA on the primary channel. Furthermore, the AP announces information about the primary channel of the BSS, and the primary channel is always included in the channels through which management frames (e.g., beacon frames, probe response frames, etc.) are transmitted.

[0139] Figure 8 This is a diagram illustrating an example of channel access based on the master channel that can be applied according to this disclosure.

[0140] Figure 8 The example illustrates a primary channel-based channel access scenario within an 80 MHz bandwidth. (See reference...) Figure 8 The channels in an 80MHz bandwidth can be referred to as follows.

[0141] P20: Main 20 MHz channel

[0142] S20: Secondary 20 MHz channel (if the bandwidth is 40 MHz, it corresponds to the remaining 20 MHz secondary channel excluding P20)

[0143] S40: Secondary 40 MHz channel (if the bandwidth is 80 MHz, it corresponds to the remaining 40 MHz secondary channel excluding P20 and S20)

[0144] Similarly, channels with bandwidths exceeding 80 MHz can be referred to as follows.

[0145] S80: Secondary 80 MHz channel (if the bandwidth is 160 MHz, it corresponds to the remaining 80 MHz secondary channel excluding P20, S20 and S40)

[0146] S160: Secondary 160 MHz channel (if the bandwidth is 320 MHz, this corresponds to the remaining 160 MHz secondary channel excluding P20, S20, S40, and S80)

[0147] S320: Secondary 320 MHz channel (if the bandwidth is 640 MHz, it corresponds to the remaining 320 MHz secondary channel excluding P20, S20, S40, S80 and S160)

[0148] In conventional wireless LAN systems, a backoff counter is set for the primary channel. For example, the STA can perform CCA (e.g., physical CS and virtual CS) to determine whether the medium on the primary channel is idle or busy. Figure 8 In the example, if the state of the medium on P20 is determined to be busy based on a CCA for P20 (e.g., physical CS and / or virtual CS (NAV)), the STA does not decrement the backoff counter (BC). However, if the state of the medium on P20 is determined to be idle, the STA can decrement the BC. Through this backoff process, when the BC expires (i.e., when the value of the BC becomes 0), the STA can check (e.g., perform a CCA) the state of the medium on S20 and S40. The STA can then transmit PPDUs (or frames) on idle channels in S20 and S40, as well as on the main channel. Figure 8 In the example, when the BC for P20 expires, S40 is busy and S20 is idle, so a 40 MHz PPDU can be sent on both P20 and S20.

[0149] Channel Access Based on Secondary Channel

[0150] The aforementioned channel access operation based on the primary channel can prevent interference and protect PPDU transmission because all frame exchanges between STAs and APs are performed according to the status of the primary channel. On the other hand, if only the primary channel is busy and the secondary channel is idle, channel access cannot be performed only on the secondary channel, which does not include the primary channel, resulting in inefficiency from a media usage perspective. For example, in Figure 8 In the example, if P20 is busy and S20 and S40 are both idle, then a portion of the 60 MHz bandwidth is wasted.

[0151] To improve wireless LAN systems, a new method for accessing secondary channels based on secondary channels is needed, even when the primary channel is not idle.

[0152] Various examples of secondary channel access described below are presented in this disclosure.

[0153] In describing this disclosure, Secondary Channel Access (SCA) means that the STA accesses the secondary channel (i.e., the medium on the secondary channel), while the primary channel (i.e., the medium on the primary channel) is busy (e.g., due to OBSS traffic or other circumstances). Here, the AP or non-APSTA may determine that the primary channel is busy based on physical carrier sensing and / or virtual carrier sensing and / or NAV settings, etc.

[0154] In this disclosure, for ease of explanation, the term "secondary channel" is used to refer to one or more channels other than the primary channel. However, this disclosure is not limited to this, and channels may also be referred to as non-primary channels. Furthermore, secondary channel access may be referred to as non-primary channel access (NPCA).

[0155] Figure 9 This is a flowchart illustrating a method for a first STA to perform channel access according to an embodiment of the present disclosure. In the description... Figure 9 and Figure 10 In this context, "non-primary channel" can refer to any channel other than the primary channel (e.g., secondary channel).

[0156] The first AP may send a request frame (S910) to the second AP, which includes first information related to the non-main channel access procedure on the first channel of the first BSS (basic service set).

[0157] Here, the first channel of the first BSS associated with the first AP may overlap entirely or partially with the second channel of the second BSS associated with the second AP. For example, if the operating channels of both the first BSS and the second BSS are 320 MHz, then the first channel (e.g., 160 MHz) of the operating channels of the first BSS and the second channel of the operating channels of the second BSS may overlap. Accordingly, the first AP may send a request frame to the second AP to negotiate and perform non-primary channel access on the first channel.

[0158] Here, the first information may include at least one of the following: 1) a first bit map indicating the second channel that overlaps with the first channel among all operating channels of the second BSS; 2) a second bit map indicating at least one secondary channel in the first channel to perform backoff; 3) the set of EDCA parameters used in at least one secondary channel; 4) the maximum bandwidth of the frame transmitted based on the backoff process on at least one secondary channel; or 5) information related to a threshold for determining whether the state of a particular channel adjacent to at least one secondary channel is idle.

[0159] The first AP can receive a response frame (S920) from the second AP, which includes second information indicating whether the request frame is accepted.

[0160] In other words, the first AP can receive a response frame from the second AP, which includes second information indicating whether the second AP accepts the first information sent via the request frame. Here, the second information can be indicated by a status code field included in the response frame. For example, the second information could indicate acceptance of the first information, rejection of the first information, or a suggestion of information other than the first information.

[0161] For example, based on the suggestions of the second information regarding other information besides the first information, the response frame may include other information suggested by the second AP.

[0162] The first AP may send a first frame (S930) to at least one STA, including third information related to the non-master channel access procedure on the first channel, based on a request frame and / or a response frame. Here, the at least one STA may be an STA that has performed an association operation for the first BSS (i.e., at least one STA within the first BSS).

[0163] In other words, the first AP can determine the information related to non-primary channel access to be sent through the first frame based on the second information in the response frame. Here, the first frame may include a beacon frame or a probe response frame.

[0164] For example, based on the second information indicating that the first information is accepted, the third information may include at least one of the following: the total bandwidth of the first BSS operating channel, the bandwidth of the first channel, or a second bitmap indicating at least one secondary channel (on which backoff will be performed). Here, the at least one secondary channel (on which backoff will be performed) included in the third information may be the same as the at least one secondary channel on which backoff will be performed as indicated by the first information. Additionally, the bandwidth of the first channel included in the third information may be the same as the bandwidth of the channel indicated by the first bitmap included in the first information.

[0165] Additionally, the first AP, together with at least one STA transmitting the beacon frame, can perform a backoff procedure for at least one secondary channel based on the first frame. Here, a network allocation vector (NAV) can be set on the primary channel within the first channel (i.e., the state of the first channel can be set to busy).

[0166] Based on the backoff count value becoming 0 according to the backoff process on the primary channel, at least one STA can perform an idle channel assessment (CCA) on a specific channel adjacent to at least one secondary channel. For example, if the state of the specific channel is idle based on the CCA result value for the specific channel, the first AP can send a second frame to at least one STA in the channel group including at least one secondary channel and the specific channel, or receive a second frame from at least one STA.

[0167] Figure 9 The methods described in the examples can be derived from... Figure 1 The first device (100) is executed. For example, Figure 1 One or more processors (102) of the first apparatus (100) may send a request frame, including first information relating to a non-primary channel access procedure on a first channel of the first BSS, to the second AP via one or more transceivers (106). One or more processors (102) may receive a response frame, including second information indicating whether the request frame is accepted, from the second AP via one or more transceivers (106). One or more processors (102) may send a first frame, including third information relating to a non-primary channel access procedure on the first channel, to at least one STA via one or more transceivers (106) based on the request frame and the response frame.

[0168] Furthermore, one or more memories (104) of the first device (100) may store information for execution by one or more processors (102) in order to perform the operation. Figure 9 The example or the command described in the example below.

[0169] Figure 10This is a flowchart illustrating a method for a second AP to perform channel access according to one embodiment of the present disclosure.

[0170] The second AP can receive a request frame (S1010) from the first AP, which includes first information related to the non-main channel access procedure on the first channel of the first BSS.

[0171] In other words, if some or all of the operating channels of the BSS associated with the second AP overlap with the operating channels of the first BSS associated with the first AP, the second AP can receive a request frame from the first AP, which includes information related to non-primary channel access on the overlapping channels of the first AP.

[0172] The second AP can send a response frame to the first AP, including second information indicating whether the request frame is accepted (S1020).

[0173] In other words, the second AP can send a second message to the first AP via a response frame, indicating whether to accept the information related to non-main channel access included in the request frame.

[0174] For reference Figure 9 As described, based on request and response frames, a backoff procedure can be performed between a first AP and at least one STA on at least one non-primary channel within the first channel. Taking the backoff procedure into account, a second AP can determine / perform operations on a second channel overlapping with the first channel.

[0175] Figure 10 The methods described in the examples can be derived from... Figure 1 The second device (200) is executed. For example, Figure 1 One or more processors (202) of the second device (200) may receive a request frame from the first AP via one or more transceivers (206) including first information relating to a non-master channel access procedure on a first channel of the first BSS. One or more processors (202) may send a response frame to the first AP via one or more transceivers (206) including second information indicating whether the request frame is accepted.

[0176] Furthermore, one or more memories (204) of the second device (200) may store information for execution by one or more processors (202) in order to perform the operation. Figure 10 The example or the command described in the example below.

[0177] Figure 9 and Figure 10 The examples may correspond to some of the various examples in this disclosure. The various examples in this disclosure will be described in more detail below, including... Figure 9 and Figure 10 Examples.

[0178] Implementation Method 1

[0179] This implementation relates to the STA's ability to access secondary channels.

[0180] Unlike existing primary channel access, which is largely supported by STAs, secondary channel access (SCA) can be performed by STAs with SCA capabilities (e.g., AP STAs and / or non-AP STAs). For example, AP STAs and non-AP STAs can notify each other whether they support SCA capabilities and / or whether SCA capabilities are enabled.

[0181] The capability for SCA can be defined by whether Type 1 CCA can be performed based on whether a WLAN frame is decoded / identified on the secondary channel (i.e., whether a preamble defined by the WLAN system is detected in the frame of the received PPDU (PD). For Type 1 CCA for the secondary channel, similar to NAV setting / resetting (for the primary channel) performed on an existing primary channel via PD-based CCA (i.e., NAV update based on the duration information of the detected preamble), NAV setting / resetting for the secondary channel can be applied based on the duration information of the preamble detected by Type 1 CCA on the secondary channel.

[0182] Additionally, the capability for SCA can be defined based on whether a second type of CCA based on Guard Interval Detection (GID) or Energy Detection (ED) can be performed on the secondary channel. GID may include determining whether a guard interval symbol defined by the wireless LAN system is detected, and ED may include determining whether a signal greater than or equal to any strength is detected, regardless of whether it is a signal / packet defined by the wireless LAN system. Furthermore, different or independent detection thresholds (e.g., thresholds for received signal strength) can be defined for the first type of CCA and the second type of CCA.

[0183] Based on these various types of CCAs, various levels of SCA capabilities can be defined.

[0184] SCA capability level 0 corresponds to the ability not to perform backoff on the secondary channel. That is, similar to traditional primary channel-based channel access, a second type of CCA (e.g., GID-based CCA and / or ED-based CCA) can be performed on the secondary channel.

[0185] SCA capability level 1 can correspond to the ability to perform backoff simultaneously on a secondary channel. If there is more than one secondary channel in the operation channel, type 1 CCA (e.g., PD-based CCA) can be performed on one secondary channel at a time, and type 1 CCA / backoff on multiple secondary channels at the same time may not be supported.

[0186] SCA capability level 2 can correspond to the ability to perform backoff on multiple secondary channels simultaneously. If there is one or more secondary channels in the operational channel, Type 1 CCA (e.g., PD-based CCA) can be performed on one or more secondary channels.

[0187] Such SCA capabilities can be included in capability information elements (e.g., UHR capability IEs) specific to a particular version / generation of the wireless LAN system. For example, an AP can send a capability IE containing information indicating whether it supports SCA capabilities in beacon frames, probe response frames, association request frames, reassociation request frames, etc. Similarly, a STA can send a capability IE containing information indicating whether it supports SCA capabilities in probe request frames, association request frames, reassociation request frames, etc.

[0188] Implementation Method 2

[0189] This implementation method relates to the operation process of secondary channel access.

[0190] For STAs, a basic NAV and an intra-BSS NAV can be set. The basic NAV can be updated based on PPDUs identified as inter-BSS or PPDUs that cannot be identified as intra-BSS or inter-BSS. The intra-BSS NAV can be updated based on PPDUs identified as intra-BSS.

[0191] Specifically, the STA behavior when the NAV for the main channel is running (i.e., the NAV is set / reset and has not yet expired) can be assumed as follows.

[0192] For example, when the AP performs frame exchange with the first STA associated with the BSS within the TXOP acquired by the AP, it can set / reset the BSS-based NAV for the primary channel for the second STA within the BSS. Alternatively, it can be assumed that the second STA, which is operating the BSS-based NAV for the primary channel, accesses a secondary channel (e.g., on a secondary channel identified as idle) and sends frames to the AP. In this case, while the AP is performing a transmission within the TXOP (e.g., sending downlink data on the primary channel, sending ACKs for uplink data, etc.), the AP may not receive frames sent to the AP by the second STA on the secondary channel.

[0193] With this in mind, it can be expected that if the default NAV is set / reset on the primary channel by a PPDU associated with a BSS other than its own (e.g., an OBSS), or by a PPDU not classified / identified as its own or another BSS, the STA can successfully perform frame switching on the SCA, and the STA can perform the SCA while the default NAV for the primary channel is in operation. In other words, the STA can perform the SCA while the default NAV for the primary channel is set (or in operation).

[0194] Implementation Method 2-1

[0195] This implementation relates to frame transmission on a secondary channel.

[0196] Figure 11 This is a diagram illustrating an example of secondary channel access according to this disclosure.

[0197] In reference Figure 8 In the case of conventional primary channel-based channel access, when backoff is performed at P20 and the backoff counter expires (i.e., the BC value becomes 0), frames can be transmitted on one or more secondary channels and P20, depending on whether one or more secondary channels are idle or busy.

[0198] First, when P20 is busy, STA performs the backoff process on one or more secondary channels (referred to as "first one or more secondary channels") that are capable of performing backoff.

[0199] In this regard, assuming that a backoff process based on a randomly selected backoff counter is not performed on the secondary channel, if multiple adjacent STAs with similar operating channels immediately perform frame transmission on an idle channel (without performing a backoff process) based on the CCA result for a short time interval (e.g., one time slot) on a channel including the secondary channel (or overlapping with the secondary channel), multiple STAs may transmit frames simultaneously, and the channel may be wasted due to this possibility of collision. Therefore, to improve channel utilization, a backoff process can be performed on the secondary channel.

[0200] Furthermore, if the remaining length of the NAV timer for the primary channel is less than a predetermined threshold, the STA may not perform secondary channel access (or backoff on the secondary channel). In other words, if the remaining length of the NAV timer for the primary channel is greater than or equal to the predetermined threshold, secondary channel access (or backoff on the secondary channel) may be performed.

[0201] For example, such a predetermined threshold can be associated with the TXOP length on the secondary channel. For instance, if the current remaining NAV timer for the primary channel does not have enough time to acquire the TXOP on the secondary channel, the STA may not perform backoff on the secondary channel.

[0202] Next, when the backoff counter on the first or more secondary channels expires (i.e., the BC value becomes 0), the STA may perform a second type of CCA on one or more additional secondary channels, in addition to the first or more secondary channels on which the backoff process was performed. For example, the STA may determine whether the result of the second type of CCA on another secondary channel (i.e., the additional secondary channel) is idle or busy during a predetermined time length (e.g., PIFS) before the backoff counter on the first secondary channel performing the backoff process becomes 0.

[0203] Therefore, the STA can perform backoff on the first one or more secondary channels whose backoff counters have expired and on the second one or more secondary channels corresponding to the additional secondary channels determined to be idle according to the second type CCA, in order to perform PPDU / frame transmission. If all secondary channels except the first one or more secondary channels on which backoff has been performed (i.e., the secondary channels on which the second type CCA has been performed) are busy, the second one or more secondary channels may not include any secondary channels other than the secondary channels on which the backoff counters have expired.

[0204] For example, in Figure 11 In the example, S20 is a secondary channel on which a backoff process based on the first type of CCA is performed, and a second type of CCA can be performed on S40 without backoff. When the backoff counter on S20 expires, and as a result of the second type of CCA for a predetermined period of time prior to this, both 20 MHz channels of S40 are idle, and PPDUs corresponding to 60 MHz of S20 and S40 within an 80 MHz bandwidth, excluding P20, can be transmitted (i.e., a second one or more secondary channels include S20 and S40). In this case, the PPDU transmitted on the second one or more secondary channels can be an 80 MHz bandwidth PPDU including information indicating that P20 has been punctured, and the MAC frame transmitted by the STA performing secondary channel access can be included in the punctured PPDU.

[0205] If the backoff counter for S20 expires, and S40 is busy as a result of a second type of CCA during a predetermined time interval prior to this, a PPDU corresponding to 20 MHz of S20 can be transmitted (i.e., a second or more secondary channels include S20). In this case, the PPDU transmitted on the second or more secondary channels can be an 80 MHz bandwidth PPDU including information indicating that P20 and S40 are punctured, and the punctured PPDU can include a MAC frame transmitted by the STA performing secondary channel access.

[0206] Additionally, PPDU / frames transmitted by a STA on one or more secondary channels can be sent to an AP or another STA.

[0207] exist Figure 11 In the example, the STA can set / reset the basic NAV based on frames received simultaneously with the backoff procedure performed on the primary channel. During the basic NAV operation on the primary channel, the STA can perform the backoff procedure on S20. Backoff on S20 can be performed via PD-based CCA, and the time delay due to the handover operation can occur between the PD-based CCA or backoff stop on the primary channel and the PD-based CCA or backoff start on the secondary channel. The CCA on S20 is not limited to PD-based CCA (i.e., Type 1 CCA), and can also be performed using GID-based or ED-based CCA (i.e., Type 2 CCA).

[0208] Implementation Method 2-2

[0209] This implementation is for TXOP on the secondary channel.

[0210] Since a CCA must be performed on P20 when the default NAV for the primary channel expires, the termination point of the TXOP on the secondary channel can be before the default NAV for the primary channel expires. Accordingly, the TXOP for the secondary channel can be acquired / set to end before the default NAV for the primary channel expires.

[0211] If a STA acquires / sets a TXOP for the secondary channel to end after the default NAV for the primary channel expires, other STAs that do not support secondary channel access (e.g., traditional STAs) can transmit frames on a channel including the primary channel (i.e., both the primary and secondary channels) after the default NAV for the primary channel expires. Furthermore, the STA performing secondary channel access may not receive frames transmitted by other STAs on a channel including the primary channel. Additionally, if the Target Beacon Transmission Time (TBTT) is set while the default NAV is running, the AP should prepare to transmit beacons on a channel including the primary channel immediately after the default NAV expires. However, it may be unable to transmit beacons in time due to the TXOP on the secondary channel, and other STAs may not receive the beacons that the AP will transmit at the scheduled time and may have to wait for a longer period. Therefore, by setting the TXOP for the secondary channel to end before the primary NAV expires, frame switching can be performed normally on a channel including the primary channel.

[0212] Additionally, if there is insufficient time to set / acquire a TXOP on the secondary channel (e.g., when the default NAV expiration time for the primary channel is less than a predetermined threshold (related to the TXOP length)), the STA may not transmit frames on the secondary channel or may perform backoff on the secondary channel. For example, if the time interval between the backoff counter expiration time for the secondary channel and the default NAV end time for the primary channel is insufficient for frame switching (or insufficient for setting / acquiring a TXOP), the STA may not perform frame transmission on the secondary channel.

[0213] Reference Figure 11 For example, a STA that wants to acquire TXOP through the backoff process on S20 and whose backoff counter has expired can set / acquire TXOP such that its length is shorter than the remaining time of the basic NAV for the main channel (i.e., so that TXOP ends before the basic NAV ends).

[0214] Implementation Method 3

[0215] This implementation relates to the transmission or reception operations of a STA performing secondary channel access.

[0216] A STA performing secondary channel access can transmit frames / PPDUs on a secondary channel during the time when the NAV for the primary channel is operating. For example, a STA can transmit frames / PPDUs on one or more idle secondary channels (e.g., the primary channel and (if any) busy secondary channels) by excluding / punching some channels, based on the backoff process performed on one or more first secondary channels and the CCA results of one or more additional secondary channels for which backoff has not yet been performed.

[0217] Additionally or alternatively, a TXOP for the secondary channel that begins with frame / PPDU transmission on the secondary channel may be set to end before the NAV on the primary channel. The TXOP length can be set / indicated by the duration information of the frame sent or received by the STA performing secondary channel access (e.g., the value of the duration / ID field). For example, the value of the duration / ID field can be set to the value of the time required for the exchange of frames / PPDUs following the corresponding frame / PPDU (e.g., the length of the corresponding frame / PPDU and the inter-frame gap (IFS)).

[0218] Alternatively or additionally, the EDCA parameter set for each (first) secondary channel for which backoff is performed at the transmitting STA can be set to the EDCA parameter set for the primary channel, the MU EDCA parameter set, or a new EDCA parameter set. This EDCA parameter set can be applied equally to all (first) secondary channels, or it can be applied differently.

[0219] In this disclosure, the STA receiving frames transmitted via a secondary channel can perform frame detection on the secondary channel while the NAV operates on the primary channel. For example, the STA may have frames to transmit and perform backoff on the secondary channel, receive frames during the backoff period on the secondary channel, or attempt to receive frames addressed to itself on the secondary channel even when there are no frames to transmit. Furthermore, the STA can perform NAV setup / reset for the secondary channel based on the duration information of frames detected on the secondary channel.

[0220] Alternatively or additionally, the EDCA parameter set for each (first) secondary channel that performs backoff at the receiving STA can be set to the EDCA parameter set for the primary channel, the MU EDCA parameter set, or a new EDCA parameter set. This EDCA parameter set can be applied equally to all (first) secondary channels, or it can be applied differently.

[0221] Implementation Method 4

[0222] Implementation 4 relates to a process for an AP to announce information related to secondary channel access and information related to secondary access.

[0223] If the BSS operating channel of an AP (or AP MLD) overlaps with the BSS (i.e., OBSS) operating channel of an adjacent AP (i.e., a neighboring AP), the SCA within the AP's BSS and the SCA within the neighboring AP's BSS may interfere with each other. For example, if an AP successfully performs SCA within its BSS and uses two secondary channels to transmit / receive PPDUs / frames, and the AP's secondary channel for transmitting PPDUs / frames overlaps with the primary channel of another AP, it may reduce the channel access opportunities of that other AP.

[0224] For example, suppose Figure 11 STA is Figure 12 AP 1. Due to Figure 12 AP 1's S20 corresponds to AP 2's P20 (i.e., AP 1's S20 and AP 2's P20 overlap). Therefore, if AP 1 uses all secondary channels to transmit PPDU / frames, AP 2 may not be able to use P20 and S20. In other words, if AP 1 performs SCA, the following problem may occur: AP 2 will not have the opportunity to perform PCH-based channel access.

[0225] Additionally, if one AP has SCA capability but another AP does not, the following problem arises: the longer the AP with SCA capability occupies the channel, the less opportunity the other AP has to access the channel.

[0226] Therefore, the AP can notify the STA of information related to SCA operation, so that the STA can use SCH while taking into account the surrounding circumstances (e.g., whether another STA has the capability for SCA, the operating channel of the BSS to which the STA is connected, channel state information related to the STA, information related to the OBSS, etc.).

[0227] Implementation Method 4-1

[0228] Implementation 4-1 relates to information related to SCA operations sent from the AP to the STA.

[0229] The AP can send various types of information related to SCA operation to the STA via management frames (e.g., beacon frames, probe response frames, etc.). For example, a management frame may include a UHR operation IE or an SCA operation-related IE, and the UHR operation IE or SCA operation-related IE may include various types of information related to SCA operation. The STA can perform SCA-related operations based on the various types of SCA operation-related information received from the AP.

[0230] As an example of this disclosure, information related to SCA operation may include information about whether SCA is permitted, the maximum bandwidth on which frames / PPDUs can be transmitted on the SCH when SCA is performed, information about one or more secondary channels used as references for SCA (i.e., channels on which backoff is to be performed), and / or CCA threshold information related to the secondary channels.

[0231] Specifically, information about whether an SCA is allowed can be indicated through fields related to whether an SCA is allowed (e.g., an SCA allow field), but the name of the field can be changed. For example, suppose the SCA allow field consists of 1 bit. In this case, if the SCA allow field value is 1 (or 0), it can mean that the SCA is allowed, and if the SCA allow field value is 0 (or 1), it can mean that the SCA is not allowed.

[0232] Additionally or alternatively, one of the bandwidths of 20 MHz, 40 MHz, 80 MHz, 160 MHz, 320 MHz, and 640 MHz may be indicated as the maximum bandwidth through which a STA can transmit frames / PPDUs on the SCH when performing SCA. The maximum bandwidth through which a STA can transmit frames / PPDUs on the SCH may not exceed the operating bandwidth of the BSS (or the bandwidth of the BSS operating channel) associated with the STA. The operating bandwidth of the BSS (or the bandwidth of the BSS operating channel) may be collectively referred to as the bandwidth on which the BSS operates. As described above, the AP may send information to the STA via management frames (e.g., beacon frames and / or probe response frames) regarding the maximum bandwidth through which it can transmit frames / PPDUs on the SCH. Information regarding the maximum bandwidth through which frames / PPDUs can be transmitted on the SCH may be indicated via the SCA bandwidth field, but the name of this field may be changed.

[0233] For example, suppose the BSS operating bandwidth is 160 MHz, and one or more SCHs of the S80 are idle. In this case, if the maximum bandwidth advertised by the AP (i.e., the maximum bandwidth that can be used to send frames / PPDUs on the SCH) is 80 MHz, then the STA can send and receive frames in 80 MHz PPDU form on the excluded channels.

[0234] Additionally or alternatively, information regarding one or more secondary channels used as a reference for SCA (i.e., channels on which backoff is to be performed) can be used to indicate the channels on which backoff is to be performed, based on the BSS operating bandwidth or the maximum bandwidth on which frames / PPDUs can be transmitted. For example, information regarding one or more secondary channels used as the basis for SCA can be configured via a bitmap.

[0235] For example, such as Figure 11As shown, if the total bandwidth (e.g., the bandwidth of the BSS operating channel) is 80 MHz and backoff is performed based on the first secondary channel, one or more secondary channels used as the basis for SCA can be configured with a 3-bit bitmap. Each bit constituting the 3-bit bitmap can correspond to each 20 MHz secondary channel. For example, the bitmap can be configured with "100" (i.e., the bitmap is configured to indicate backoff on the first 20 MHz secondary channel). However, this is merely an example, and the bitmap can include bits corresponding to the PCH. In this case, information indicating one or more secondary channels used as the basis for SCA can be configured with a 4-bit bitmap.

[0236] As described above, the first bit of the bitmap can correspond to the highest frequency 20 MHz channel, and the last bit of the bitmap can correspond to the lowest frequency 20 MHz channel. However, this is only an example, and the first bit of the bitmap can correspond to the lowest frequency 20 MHz channel, and the last bit of the bitmap can correspond to the highest frequency 20 MHz channel. Furthermore, the bandwidth used as the basis for the bitmap is not limited to 20 MHz, and can be implemented as 40 MHz, 80 MHz, or 160 MHz, etc.

[0237] Additionally or alternatively, the CCA threshold information associated with the secondary channel may include information about a threshold used as a criterion for determining the channel state (e.g., a criterion for determining whether the channel state is idle or busy) through CCA in one or more SCHs on which SCA is performed. The lower the threshold used as the criterion for determining the channel state via CCA (i.e., the threshold compared to channel measurements), the higher the probability that the channel state will be determined to be busy, even if the channel measurements (e.g., Received Signal Strength Indicator (RSSI)) are low. In this case, the CCA may include a first type of CCA and / or a second type of CCA.

[0238] For example, the threshold used as a criterion for determining the channel state can be determined / set to a fixed / predefined value (e.g., -82 dBM or -72 dBM, etc.). Additionally or alternatively, the threshold used as a criterion for determining the channel state can be determined / set to add / subtract a variable value (e.g., 4 dBM, 8 dBM, etc.) to / from the fixed / predefined value. In this case, the AP can send only the value added / subtracted from the threshold to the STA.

[0239] As an example of this disclosure, Figure 13 This illustrates a procedure for executing an SCA based on SCA-related information declared by the AP. For example... Figure 13As shown, the AP can announce to the STA information regarding the BSS operating bandwidth set to 160 MHz, information indicating SCA permission, information regarding the maximum bandwidth of PPDUs that can be transmitted through the SCA set to 40 MHz, and information regarding the secondary channel used as a reference for the SCA (i.e., the channel on which backoff is performed). The AP can send / announce the above information to the STA via beacon frames.

[0240] Here, information about the channel on which backoff is performed can be configured in bitmap format. For example, as... Figure 13 As shown, if the information about the channel on which backoff is performed is set to an 8-bit bitmap (e.g., "00100000"), this can indicate that the first 20 MHz (i.e., the second SCH) of S40 is the channel on which backoff is performed. Here, it is assumed that the first bit of the bitmap corresponds to the 20 MHz channel with the lowest frequency, and the last bit of the bitmap corresponds to the 20 MHz channel with the highest frequency (i.e., in ascending order).

[0241] If the AP announces information related to SCA, the STA can perform backoff based on the information announced according to the first SCH of S40. If the backoff count becomes 0 and the second SCH of S40 is idle, the STA can transmit a frame on S40 (to another STA (e.g., AP)). Furthermore, even if the channel state of S80 is idle, since the maximum bandwidth of the PPDU that can be transmitted via SCA is 40 MHz, the STA may not perform CCA on a specific SCH of S80 and may not use it.

[0242] The above example demonstrates that even if the PCH is busy, the STA can still use the SCH to send frames, thereby improving the efficiency of channel usage.

[0243] Implementation Method 5

[0244] Implementation method 5 relates to operations related to the SCA of the STA.

[0245] In one embodiment of this disclosure, during the NAV setting period in the PCH, the STA can transmit frames / PPDUs on the SCH by performing SCA. For example, the STA can identify / determine the channel state of one or more SCHs based on backoff performed on one or more SCHs and CCA results of one or more SCHs on which backoff was not performed. If the channel state of one or more SCHs is idle, the STA can transmit frames / PPDUs on one or more SCHs (to another STA (e.g., AP)) where the PCH is excluded / punctured.

[0246] Additionally or alternatively, the set of TXOPs based on SCAs (i.e., backoffs, etc.) performed on one or more SCHs can be set to end before the NAV on the PCH. That is, the end time of a TXOP that begins with a frame / PPDU transmission on an SCH can be set / determined to end before the NAV on the PCH.

[0247] Here, the length of the TXOP set on the SCH can be set / indicated by the duration / ID field of the frame sent in the corresponding TXOP. For example, the value of the duration / ID field can be set to a value corresponding to the time required for the exchange of frames / PPDUs after the corresponding frame / PPDU (including the inter-frame interval (IFS)).

[0248] Additionally or alternatively, the STA may obtain information about one or more SCHs for which backoff is performed, such as through management frames (e.g., beacon frames) sent from the AP. In this case, the information about one or more SCHs may include information about whether frame / PPDU transmission is possible on one or more SCHs. For example, if the STA performing SCA is the AP, the STA may utilize information sent by the STA (e.g., information about whether frame / PPDU transmission is possible on the SCH and / or information about one or more SCHs for which backoff is performed, etc.).

[0249] Additionally or alternatively, the STA can obtain information from the AP via management frames (e.g., beacon frames) about the maximum bandwidth that the STA can transmit frames / PPDUs on the SCH. If the STA performing SCA is the AP, the STA can utilize the information about the maximum bandwidth that the STA can transmit frames / PPDUs on the SCH that the STA transmits.

[0250] Additionally or alternatively, the STA may obtain a threshold for either a first type or a second type of CCA for determining the channel state (i.e., whether the channel is busy or idle) via a management frame (e.g., a beacon frame). That is, if the value measured by the STA on the SCH (e.g., channel-related RSSI or power) exceeds the threshold, the channel state of the corresponding SCH can be determined to be busy.

[0251] Alternatively or additionally, the EDCA parameter set for each SCH on which backoff is performed can be set to the EDCA parameter set in the PCH, the MU EDCA parameter set, or a new EDCA parameter set. The EDCA parameter set can be applied equally or differently to all SCHs.

[0252] As an example of this disclosure, even during the time period when NAV is set in the PCH, the STA receiving frames transmitted via the SCA can perform frame detection on the SCH. For example, the STA can perform backoff on the SCH for a frame to be transmitted. As another example, when there are no frames to be transmitted, the STA can attempt to receive a frame addressed to itself on the SCA. Furthermore, the STA can perform NAV setting / resetting based on the value of the interval / ID field of the frames detected on the SCH.

[0253] Additionally or alternatively, the STA may obtain information about one or more SCHs for which backoff is performed, such as through management frames (e.g., beacon frames) sent from the AP. In this case, the information about one or more SCHs may include information about whether frame / PPDU transmission is possible on one or more SCHs. For example, if the STA performing SCA is the AP, the STA may utilize information sent by the STA (e.g., information about whether frame / PPDU transmission is possible on the SCH and / or information about one or more SCHs for which backoff is performed, etc.).

[0254] Additionally or alternatively, the STA may obtain a threshold for either a first type or a second type of CCA for determining the channel state (i.e., whether the channel is busy or idle) via a management frame (e.g., a beacon frame). That is, if the value measured by the STA on the SCH (e.g., RSSI or channel-related power) exceeds the threshold, the channel state of the corresponding SCH can be determined to be busy.

[0255] Alternatively or additionally, the EDCA parameter set for each SCH on which backoff is performed can be set to the EDCA parameter set in the PCH, the MU EDCA parameter set, or a new EDCA parameter set. The EDCA parameter set can be applied equally or differently to all SCHs.

[0256] Implementation Method 5-1

[0257] Implementation 5-1 relates to a method for achieving efficient SCA by dividing the channel, including the BSS operating channel, into multiple sets to perform backoff. In this case, in addition to the information advertised by the AP for SCA as described in Implementations 4, 4-1, and 5, information described below (e.g., channel subset element information, SCA channel bitmap size information, etc.) may also be advertised / transmitted.

[0258] As an example of this disclosure, the AP may announce information about the bandwidth criteria (or units) used to divide the bandwidth of the entire BSS operating channel into one or more channel subsets for SCA (i.e., channel subset unit information).

[0259] For example, suppose the (sub)field size for indicating channel subset element information is 2 bits. If the (sub)field value for indicating channel subset element information is 0 (i.e., if the (sub)field indicates no subset), this could mean that the BSS operating channel has not been divided into one or more subsets. If the (sub)field value is 1, this could mean that the bandwidth reference / unit value used to divide the BSS operating channel into one or more subsets is 40 MHz. If the (sub)field value is 2, this could mean that the bandwidth reference / unit value used to divide the BSS operating channel into one or more subsets is 80 MHz. If the (sub)field value is 3, this could mean that the bandwidth reference / unit value used to divide the BSS operating channel into one or more subsets is 160 MHz.

[0260] However, this is only one implementation, and the size of the (sub)field indicating channel subset cell information can be set to 3 bits. In this case, the bandwidth reference / cell value can be indicated as 320 MHz through this (sub)field.

[0261] Additionally, the AP can notify the STA of the size of the bitmap of one or more SCHs (i.e., the SCHs on which backoff is performed) used as a reference when performing SCA (i.e., SCHs on which backoff is performed).

[0262] For example, suppose the size of the (sub)field indicating the SCA channel bitmap size information is 2 bits. If the value of the (sub)field indicating the SCA channel bitmap size information is 0, this can mean that the SCA channel bitmap size is 4 bits. If the value of the (sub)field indicating the SCA channel bitmap size information is 1, this can mean that the SCA channel bitmap size is 8 bits. If the value of the (sub)field indicating the SCA channel bitmap size information is 2, this can mean that the SCA channel bitmap size is 16 bits. If the value of the (sub)field indicating the SCA channel bitmap size information is 3, this can mean that the SCA channel bitmap size is 32 bits. Here, if there is no SCA channel bitmap indicator P20, the SCA channel bitmap size can be reduced by 1.

[0263] Here, the size of the (sub)field indicating the SCA channel bitmap size information can vary depending on the BSS operating channel. For example, if the size of the BSS operating channel is 320 MHz, the SCA channel bitmap size can be set / determined to a maximum of 16 bits.

[0264] For example, if information indicating one or more SCHs used as references when performing SCA is configured as a bitmap, then information for configuring / indicating / describing a subset of channels may not be needed. That is, it may not be necessary to configure a separate field for the bitmap corresponding to each subset. If information indicating one or more SCHs used as references when performing SCA is configured as a bitmap, then setting a bit in the bitmap corresponding to a specific channel to 1 may indicate that backoff is performed on the corresponding channel. Additionally or alternatively, there may not be a specific SCH for which backoff is performed within a subset of channels.

[0265] As an example of this disclosure, Figure 14 This example illustrates a BSS operation channel with a bandwidth of 160 MHz. Figure 14 In the diagram, the shaded portion excluding P20 can represent the SCH used as a reference for SCA (i.e., the SCH capable of performing backoff).

[0266] For example, Figure 14 (a) illustrates the case where the channel subset unit is 40 MHz. When information indicating one or more SCHs used as references during P20 and SCA execution is configured as a bitmap, the bitmap can be set to "01101001". In this case, when P20 is not indicated by the bitmap, the bitmap can be set to "01101001". In other words, one or more SCHs used as references during SCA execution for all channel subsets can be expressed / set by a single bitmap.

[0267] For example, Figure 14 (b) illustrates the case where the channel subset unit is 80 MHz. If information indicating one or more SCHs used as references when performing P20 and SCA is configured as a bitmap, the bitmap can be set to "01001000". In this case, if P20 is not indicated by the bitmap, the bitmap can be set to "1001000". In other words, one or more SCHs used as references when performing SCA for all channel subsets can be expressed / set by a single bitmap.

[0268] As another example of this disclosure Figure 15 This is a diagram used to explain the SCA channel bitmap when the bandwidth of the BSS operating channel is 320 MHz. That is, it assumes the bandwidth of the BSS operating channel is 320 MHz and the channel subset unit is 80 MHz. Figure 15 In the diagram, the shaded portion excluding P20 can indicate the channel used as a reference for SCA (i.e., a backoff SCH can be performed).

[0269] For example, if information indicating one or more SCHs used as references when performing P20 and SCA is configured as a bitmap, then the bitmap can be set to "0100100001001000". Here, if P20 is not indicated by the bitmap, then the bitmap can be set to "100100001001000". That is, one or more SCHs used as references when performing SCA for all subsets of channels can be expressed / set using a single bitmap.

[0270] Implementation Method 6

[0271] Implementation method 6 relates to a multi-AP coordination process for secondary channel access.

[0272] For example, the information related to the SCA described in Embodiments 4, 4-1, 5, and 5-1 can be information that is sent, received, and processed within a single BSS. That is, the AP and / or STA can send and receive SCA-related information associated with the BSS associated with the STA (i.e., the AP's BSS).

[0273] The operating channels of adjacent BSSs may partially or completely overlap, but are not limited to this, and the operating channels of each BSS may not overlap with each other. If the operating channels of adjacent BSSs do not overlap, the operating channels may not affect each other. However, if the operating channels of adjacent BSSs partially or completely overlap, the SCAs performed on the operating channels of each BSS may affect each other.

[0274] The following describes a method to reduce the impact / interference related to SCA by having multiple APs negotiate SCA-related information with each other.

[0275] Implementation method 6-1

[0276] Implementation 6-1 relates to sending and receiving request / response frames between multiple APs to negotiate SCA-related information. That is, a sending AP can send a request frame to a receiving AP to negotiate SCA-related information, and a receiving AP can send a response frame to the sending AP containing information about whether negotiation has been performed.

[0277] Here, request frames and / or response frames can be configured in the form of action frames. For example, request frames and / or response frames can be examples of management frames, but are not limited to this.

[0278] A request frame can be represented as an SCA protocol request frame, and a response frame can be represented as an SCA protocol response frame, but is not limited to these.

[0279] As an example of this disclosure, request frames and / or response frames may include information related to the channel on which SCA is to be performed (or the channel on which SCA can be performed) (e.g., permitted channel information), information related to one or more secondary channels on which backoff is to be performed (e.g., information about the secondary backoff channels), the maximum bandwidth on which PPDU / frames can be transmitted when performing SCA (e.g., information about the SCA bandwidth), information about the EDCA parameter set, information about the secondary channel CCA threshold, and a status code.

[0280] Specifically, the information related to the channel to which SCA is to be performed may include information indicating the channel to which SCA is to be performed (or the channel that can perform SCA). Information indicating the channel to which SCA is to be performed (or the channel that can perform SCA) among the channels constituting the BSS operation channel can be configured, taking into account the primary channel.

[0281] In other words, information related to the channel for which SCA is to be performed can indicate the channel (or the channel for which SCA can be performed) among all channels, including the primary channel. In describing this disclosure, BSS operating bandwidth (or the bandwidth of the BSS operating channel) may refer to the bandwidth of BSS operation.

[0282] For example, the sending AP can configure information indicating the channel for performing SCA (or a channel capable of performing SCA) based on whether it knows the BSS operation channel information of the receiving AP. In other words, it can configure information indicating the channel for performing SCA (or a channel capable of performing SCA) based on the BSS operation channel information of the receiving AP.

[0283] For example, if the transmitting AP knows information about the BSS operation channel of the receiving AP (e.g., if the transmitting AP has obtained / received information about the BSS operation channel of the receiving AP in advance), the transmitting AP can use a bitmap configuration to indicate the channel to perform SCA (or the channel on which SCA can be performed).

[0284] For example, if the bandwidth of the operating channel of the receiving AP is 160 MHz, the information indicating the channel to be used for SCA (or the channel that can be used for SCA) can be configured as an 8-bit bitmap, where each bit corresponds to a 20 MHz channel. For example, the first bit of the bitmap could correspond to the first unit bandwidth channel among the unit bandwidth channels constituting the BSS operating channel (e.g., the 20 MHz channel with the lowest frequency), and the last bit of the bitmap could correspond to the last unit bandwidth channel among the unit bandwidth channels constituting the BSS operating channel (e.g., the 20 MHz channel with the highest frequency) (i.e., in ascending order). As another example, the first bit of the bitmap could correspond to the last unit bandwidth channel among the unit bandwidth channels constituting the BSS operating channel (e.g., the 20 MHz channel with the highest frequency), and the last bit of the bitmap could correspond to the first unit bandwidth channel among the unit bandwidth channels constituting the BSS operating channel (e.g., the 20 MHz channel with the lowest frequency) (i.e., in descending order).

[0285] As another example, if the transmitting AP is unaware of information about the receiving AP's BSS operation channel (e.g., if the transmitting AP has not prior knowledge / received information about the receiving AP's BSS operation channel), the transmitting AP can configure information indicating the channel to be used for SCA by using the CCF (Channel Center Frequency). Here, CCF can represent the CF (Center Frequency) of the entire channel for which SCA is to be performed.

[0286] For example, if the channel for which SCA is to be performed is 20 MHz, 40 MHz, or 80 MHz, one CCF can be used to configure information about the channel for which SCA is to be performed. As another example, if the channel for which SCA is to be performed is 160 MHz or 320 MHz, two or three CCFs can be used to configure information about the channel for which SCA is to be performed.

[0287] As an example of this disclosure, information about one or more secondary channels for which backoff is to be performed can be configured using a bitmap. A bitmap indicating information about one or more secondary channels for which backoff is to be performed can be configured based on bitmap indication information indicating the channel for which SCA is to be performed (or the channel for which SCA can be performed).

[0288] For example, if a bitmap indicating the channel to be subject to SCA (or a channel where SCA can be performed) has a bandwidth of 80 MHz, then the bitmap indicating information about one or more secondary channels to be backed up can consist of four bits corresponding to a bandwidth of 20 MHz. Each bit of the bitmap can correspond to a bandwidth of 20 MHz. Furthermore, when a bit value in the bitmap is set to 1 (or 0), this can indicate that backing up is performed on the channel with the bandwidth corresponding to that bit. When a bit value in the bitmap is set to 0 (or 1), this can indicate that backing up is not performed on the channel with the bandwidth corresponding to that bit.

[0289] For example, the first bit of the bitmap may correspond to the first unit bandwidth channel among the channels to which SCA is to be performed (e.g., a 20 MHz channel with the lowest frequency), and the last bit of the bitmap may correspond to the last unit bandwidth channel among the channels to which SCA is to be performed (e.g., a 20 MHz channel with the highest frequency) (i.e., in ascending order). As another example, the first bit of the bitmap may correspond to the last unit bandwidth channel among the channels to which SCA is to be performed (e.g., a 20 MHz channel with the highest frequency), and the last bit of the bitmap may correspond to the first unit bandwidth channel among the channels to which SCA is to be performed (e.g., a 20 MHz channel with the lowest frequency) (i.e., in descending order).

[0290] As an example of this disclosure, the maximum bandwidth that can be used to transmit PPDU / frames during SCA execution can be 20 MHz, 40 MHz, 80 MHz, 160 MHz, 320 MHz, or 640 MHz. The bandwidth of the channel for which SCA is to be performed, indicated by information associated with the channel, can be less than the maximum bandwidth that can be used to transmit PPDU / frames.

[0291] As an example of this disclosure, information about the EDCA parameter set may include the EDCA parameter set to be used on the channel performing backoff when performing SCA.

[0292] As an example of this disclosure, information regarding the secondary channel CCA threshold can indicate a threshold used as a reference value for determining whether the state of one or more secondary channels performing SCA is idle or busy. As an example, the STA can determine whether the state of one or more secondary channels is idle or busy by comparing measurements obtained by performing CCA (e.g., Type 1 CCA or Type 2 CCA) on one or more secondary channels with the threshold.

[0293] For example, the threshold indicated by information regarding the secondary channel CCA threshold can be determined / set to a fixed / predefined value (e.g., -82 dBM or -72 dBM, etc.). Alternatively, the threshold indicated by information regarding the secondary channel CCA threshold can be determined / set to be added to / subtracted from the fixed / predefined value as a variable value (e.g., 4 dBm, 8 dBm, etc.). In this case, the AP can send only the value added to / subtracted from the threshold to another AP.

[0294] As an example of this disclosure, a status code may be included only in the response frame. For example, the status code may include information about whether the information included in the request frame is accepted / rejected. Alternatively, the status code may include information indicating that the information included in the request frame is rejected while suggesting new information. That is, if the status code indicates that new information is suggested, the response frame may include information related to the SCA proposed by the receiving AP.

[0295] Implementation method 6-2

[0296] Implementation method 6-2 relates to a multi-AP coordination process for SCA.

[0297] As an example of this disclosure, such as Figure 16 As shown in (a), a portion of the operating channel of each of the BSS of AP 1 (i.e., the BSS with BSS color value 5) and the BSS of AP 2 (i.e., the BSS with BSS color value 10) can overlap. For example, as Figure 16 As shown in (b), the bandwidth of the BSS operation channel of each of AP 1 and AP 2 can be 320 MHz, and the bandwidth of the overlapping channel of the BSS operation channels of each of AP 1 and AP 2 can be 160 MHz.

[0298] Additionally, STA 1-2 (i.e., STAs connected to the BSS of AP 1) and STA 2-1 (i.e., STAs connected to the BSS of AP 2) may exist, wherein the BSS operating channels of each of AP 1 and AP 2 overlap, but are not limited thereto.

[0299] As an example of this disclosure, such as Figure 17 As shown, AP 1 can send a request frame to AP 2 to request SCA to be performed on a channel where the BSS of AP 1 and the BSS of AP 2 overlap, which has a bandwidth (e.g., 160 MHz).

[0300] Here, if AP 1 knows information about the BSS operation channel of AP 2 (e.g., if AP 1 has previously acquired / received information about the BSS operation channel of AP 2), AP 1 can configure information about the channels through which AP 2 can perform SCA via a bitmap, and the bitmap can be included in the request frame.

[0301] For example, in the BSS operation channel of AP 2 (e.g., 320 MHz), a channel with overlapping bandwidths of the BSSs of AP 1 and AP 2 (e.g., 160 MHz) can be identified as a channel capable of performing SCA, and a bitmap indicating the channel capable of performing SCA can be configured (e.g., "0000000011111111"). In the bitmap, 0 can represent a channel with a unit bandwidth (20 MHz) that does not perform SCA, and 1 can represent a channel with a unit bandwidth that can perform SCA. Additionally, the first bit of the bitmap can represent the unit bandwidth with the lowest frequency value, and the last bit of the bitmap can represent the unit bandwidth with the highest frequency value. That is, the bits corresponding to each unit bandwidth within the bitmap can be configured in ascending order of frequency, but are not limited to this.

[0302] Additionally, information regarding secondary channels capable of backoff in channels with overlapping bandwidths of the BSS of AP 1 and the BSS of AP 2 can be included in the request frame. For example, such as Figure 17 As shown, information about the secondary channels that can perform backoff can be configured in the form of a bitmap. If the bitmap for the secondary channels that can perform backoff is configured as "01001000", this can indicate that backoff is performed on the second and fifth channels. Figure 17 The shaded area in the diagram represents a channel where backoff can be performed.

[0303] Here, the first channel of the bitmap can be the main channel, and the bits corresponding to each unit bandwidth within the bitmap can be configured in ascending order of frequency. However, this is merely one implementation, and the bits corresponding to the main channel can be omitted from the bitmap, and the bits corresponding to each unit bandwidth can be configured in descending order of frequency.

[0304] Alternatively or concurrently, the request frame sent by AP 1 to AP 2 may include the set of EDCA parameters to be used when performing SCA (i.e., the set of EDCA parameters applicable to the secondary channel for performing backoff), the maximum size of the bandwidth of the frame / PPDU sent according to SCA, or a threshold related to the CCA to be performed on one or more secondary channels (i.e., a threshold for determining the channel state of one or more secondary channels).

[0305] Here, the EDCA parameter set applied to the secondary channel performing backoff can be set to the EDCA parameter set of the primary channel, the MU EDCA parameter set, or a new EDCA parameter set. The above types of EDCA parameter sets can be applied equally or differently to all secondary channels.

[0306] For example, if AP 1 accepts the SCA-related information included in the request frame sent by AP 1, then AP 2 can send a response frame to AP 1, which includes a status code indicating that it accepts the request frame.

[0307] As another example, AP 2 can reject the SCA-related information included in a request frame sent by AP 1 and send a response frame to AP 1 containing the SCA-related information proposed by AP 2. Here, the status code included in the response frame sent by AP 2 can be set to "recommendation".

[0308] AP 1 can send a beacon frame based on a response frame received from AP 2. For example, if AP 2 accepts SCA-related information included in a request frame sent by AP 1, then AP 1 can send the SCA-related information via a beacon frame.

[0309] For example, such as Figure 17 As shown, the SCA-related information included in the beacon frame may include the bandwidth of the BSS operating channel, information indicating permission for SCA, information about the bandwidth of the auxiliary channel, and information about the channel to be backed up. In this case, the information about the bandwidth of the auxiliary channel and the information about the channel to be backed up may be information negotiated between AP 1 and AP 2 via request / response frames. AP 1 may perform SCA on at least one of the negotiated channels.

[0310] As mentioned above, an AP can negotiate an SCA (e.g., negotiate the channel on which to perform the SCA) by exchanging request / response frames with other APs.

[0311] Unlike existing wireless LAN systems that perform channel access based on the state of the primary channel, the SCA according to various examples of this disclosure can efficiently perform frame / PPDU transmission / reception on one or more secondary channels even when the primary channel is busy, thereby improving the utilization of channel resources.

[0312] The above embodiments combine the elements and features of this disclosure in a predetermined form. Unless otherwise expressly stated, each element or feature should be considered optional. Each element or feature may be implemented without being combined with other elements or features. Furthermore, embodiments of this disclosure may include combinations of some elements and / or features. The order of operations described in embodiments of this disclosure may be changed. Some elements or features of one embodiment may be included in other embodiments, or may be replaced by corresponding elements or features of other embodiments. Obviously, embodiments may include claims that are not explicitly referenced in the claims, or may be included as new claims after the application has been amended.

[0313] It will be apparent to those skilled in the art that this disclosure may be implemented in other specific forms without departing from its essential characteristics. Therefore, the above detailed description should not be construed as restrictive in every respect, but rather as illustrative. The scope of this disclosure should be determined by a reasonable interpretation of the appended claims, and all variations within the equivalent scope of this disclosure are included within its scope.

[0314] The scope of this disclosure includes software or machine-executable commands (e.g., operating systems, applications, firmware, programs, etc.) that operate in a device or computer according to methods of various embodiments, as well as non-transitory computer-readable media that cause software or commands to be stored and executable in a device or computer. Commands that can be used to program a processing system to perform the features described in this disclosure can be stored in a storage medium or a computer-readable storage medium, and the features described in this disclosure can be implemented by using a computer program product including such a storage medium. The storage medium may include, but is not limited to, high-speed random access memory, such as DRAM, SRAM, DDR RAM, or other random access solid-state storage devices, and may include non-volatile memory, such as one or more disk storage devices, optical disk storage devices, flash memory devices, or other non-volatile solid-state storage devices. The memory may optionally include one or more storage devices located remotely from the processor. The memory, or alternatively, the non-volatile memory devices in the memory include non-transitory computer-readable storage media. The features described in this disclosure can be stored in any machine-readable medium to control the hardware of a processing system and can be integrated into software and / or firmware that allows the processing system to interact with other mechanisms using the results of embodiments of this disclosure. Such software or firmware may include, but is not limited to, application code, device drivers, operating systems, and execution environments / containers.

[0315] Industrial applicability

[0316] The method proposed in this disclosure has been described in reference to examples applied to IEEE 802.11-based systems, but the method can also be applied to various wireless LAN or wireless communication systems other than IEEE 802.11-based systems.

Claims

1. A method performed by a first access point (AP) in a wireless local area network (WLAN) system, the method comprising the following steps: Send a request frame to the second AP, the request frame including first information related to the non-master channel access procedure on the first channel of the first basic service set BSS; Receive a response frame from the second AP, the response frame including second information indicating whether the request frame is accepted; as well as Based on the request frame and the response frame, a first frame including third information related to the non-master channel access procedure on the first channel is sent to at least one STA. The first channel of the first BSS associated with the first AP and the second channel of the second BSS associated with the second AP overlap in whole or in part.

2. The method according to claim 1, wherein, The first information includes a first bit map indicating the second channel in the total operation channel of the second BSS that overlaps with the first channel, and a second bit map indicating at least one auxiliary channel in the first channel that is to perform backoff.

3. The method according to claim 2, wherein, The first information includes at least one of the Enhanced Distributed Channel Access (EDCA) parameter set used in the at least one secondary channel or the maximum bandwidth of a frame transmitted based on the backoff procedure on the at least one secondary channel.

4. The method according to claim 1, wherein, The second information is indicated by the status code field included in the response frame, and The second information indicates one of the following: acceptance of the first information, rejection of the first information, or suggestion of other information besides the first information.

5. The method according to claim 4, wherein, The response frame includes the other information suggested by the second AP, based on the suggestions made by the second information regarding other information besides the first information.

6. The method according to claim 2, wherein, The third information, based on the second information indicating acceptance of the first information, includes at least one of the following: the total bandwidth of the first BSS operating channel, the bandwidth of the first channel, or the second bitmap indicating the at least one secondary channel.

7. The method according to claim 1, wherein, Based on the backoff process performed for the at least one secondary channel according to the first frame, a second frame is sent from the first AP to the at least one STA within a channel group including the at least one secondary channel, or the second frame is sent from the at least one STA to the first AP.

8. The method according to claim 7, wherein, At least one STA performs a Clear Channel Assessment (CCA) on a specific channel in the channel group that is adjacent to at least one secondary channel, and The state of the specific channel is determined based on the CCA result value for that specific channel.

9. The method according to claim 8, wherein, The first information includes information related to a threshold used to determine whether the state of the particular channel is idle.

10. The method according to claim 1, wherein, Set the network allocation vector NAV on the primary channel in the first channel.

11. The method according to claim 1, wherein, The first frame includes a beacon frame or a probe response frame.

12. A first access point (AP) operating in a wireless LAN system, the first AP comprising: At least one transceiver; as well as At least one processor, said at least one processor being connected to said at least one transceiver, Wherein, the at least one processor is configured to: The request frame is sent to the second AP via the at least one transceiver, the request frame including first information related to the non-master channel access procedure on the first channel of the first basic service set BSS; The at least one transceiver receives a response frame from the second AP, the response frame including second information indicating whether the request frame is accepted; and Based on the request frame and the response frame, a first frame including third information related to the non-master channel access procedure on the first channel is transmitted to at least one STA via the at least one transceiver. The first channel of the first BSS associated with the first AP and the second channel of the second BSS associated with the second AP overlap in whole or in part.

13. A method performed by a second access point (AP) in a wireless LAN system, the method comprising the following steps: Receive a request frame from the first AP, the request frame including first information related to a non-primary channel access procedure on a first channel of the first basic service set BSS; as well as A response frame is sent to the first AP, the response frame including second information indicating whether the request frame is accepted. Specifically, based on the request frame and the response frame, a first frame including third information related to the non-master channel access procedure on the first channel is sent from the first AP to at least one STA, and The first channel of the first BSS associated with the first AP and the second channel of the second BSS associated with the second AP overlap in whole or in part.

14. A second access point (AP) operating in a wireless LAN system, the second AP comprising: At least one transceiver; as well as At least one processor, said at least one processor being connected to said at least one transceiver, Wherein, the at least one processor is configured to: The at least one transceiver receives a request frame from the first AP, the request frame including first information related to a non-primary channel access procedure on a first channel of the first basic service set (BSS); and The at least one transceiver sends a response frame to the first AP, the response frame including second information indicating whether the request frame is accepted. Specifically, based on the request frame and the response frame, a first frame including third information related to the non-master channel access procedure on the first channel is sent from the first AP to at least one STA, and The first channel of the first BSS associated with the first AP and the second channel of the second BSS associated with the second AP overlap in whole or in part.

15. A processing apparatus configured to control a first access point (AP) in a wireless LAN system, the processing apparatus comprising: At least one processor; as well as At least one computer memory, operatively coupled to the at least one processor and storing instructions for performing operations when executed by the at least one processor. The operation includes: Send a request frame to the second AP, the request frame including first information related to the non-master channel access procedure on the first channel of the first basic service set BSS; Receive a response frame from the second AP, the response frame including second information indicating whether the request frame is accepted; and Based on the request frame and the response frame, a first frame including third information related to the non-master channel access procedure on the first channel is sent to at least one STA. The first channel of the first BSS associated with the first AP and the second channel of the second BSS associated with the second AP overlap in whole or in part.

16. At least one non-transitory computer-readable medium, said at least one non-transitory computer-readable medium storing at least one instruction, wherein, The at least one instruction executed by at least one processor controls a device in a wireless LAN system to perform the following operations: Send a request frame to the second AP, the request frame including first information related to the non-master channel access procedure on the first channel of the first basic service set BSS; Receive a response frame from the second AP, the response frame including second information indicating whether the request frame is accepted; as well as Based on the request frame and the response frame, a first frame including third information related to the non-master channel access procedure on the first channel is sent to at least one STA. The first channel of the first BSS associated with the first AP and the second channel of the second BSS associated with the second AP overlap in whole or in part.

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