Silent channel-based transmission or reception method and apparatus in wireless LAN system

Abstract

Disclosed are a silent channel-based transmission or reception method and apparatus in a wireless LAN system. According to an embodiment of the present disclosure, a method performed by a station (STA) in a wireless LAN system may comprise the steps of: receiving a silent channel element including information indicating one of a plurality of combinations of channels in which communication to a first access point (AP) is allowed or channels in which communication to the first AP is not allowed within a bandwidth; and performing communication to the first AP on one or more channels based on the one combination.

Description

Technical Field

[0001] The present disclosure relates to a silent operation in a wireless local area network (WLAN) system, and more particularly, to a transmission or reception method and apparatus based on a silent channel. Background Art

[0002] New technologies have been introduced for wireless LAN (WLAN) to increase transmission rates, increase bandwidth, improve reliability, reduce errors, and reduce latency. Among WLAN technologies, the Institute of Electrical and Electronics Engineers (IEEE) 802.11 series of standards may be referred to as Wi-Fi. For example, technologies recently introduced to WLAN include the Very High Throughput (VHT) enhancements of the 802.11ac standard and the High Efficiency (HE) enhancements of the IEEE 802.11ax standard.

[0003] In order to provide a more advanced wireless communication environment, improved technologies for extremely high throughput (EHT) are being discussed. For example, technologies for MIMO and multi-access point (AP) coordination that support increased bandwidth, efficient use of multiple frequency bands, and increased spatial streams are being studied, and specifically, various technologies are being studied to support low latency or real-time services. In addition, new technologies are being discussed to support ultra-high reliability (UHR), including improvements or extensions of EHT technologies. Summary of the invention

[0004] Technical issues

[0005] The technical problem of the present disclosure is to provide a silent channel-based sending or receiving method and device in an extended bandwidth in a WLAN system.

[0006] Another technical problem of the present disclosure is to provide a method and device for sending or receiving access point silent mode information based on extended bandwidth in a WLAN system.

[0007] The technical objectives to be achieved by the present disclosure are not limited to the above-mentioned technical objectives, and those skilled in the art can clearly understand other technical objectives not described herein through the following description.

[0008] Technical Solution

[0009] According to one aspect of the present disclosure, a method performed by a station (STA) in a WLAN system may include: receiving a silent channel element, the silent channel element including information indicating one of a plurality of combinations of channels within a bandwidth that allow communication to a first access point (AP) or channels that do not allow communication to the first AP; and performing communication to the first AP on at least one channel based on the one combination.

[0010] According to additional aspects of the present disclosure, a method performed by a first access point (AP) in a WLAN system may include: sending a silent channel element to a station (STA), the silent channel element including information indicating one of multiple combinations of channels within a bandwidth that allow communication to the first AP or channels that do not allow communication to the first AP; and performing communication with the STA on at least one channel based on the one combination.

[0011] Technical Effects

[0012] According to the present disclosure, a silent channel-based transmission or reception method and apparatus in an extended bandwidth in a WLAN system may be provided.

[0013] According to the present disclosure, a method and device for sending or receiving access point silent mode information applicable to extended bandwidth in a WLAN system can be provided.

[0014] Effects achievable by the present disclosure are not limited to the above-described effects, and other effects not described herein may be clearly understood by those skilled in the relevant art through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The accompanying drawings, which are included as a part of the detailed description for understanding the present disclosure, provide embodiments of the present disclosure and describe technical features of the present disclosure together with the detailed description.

[0016] Figure 1 A configuration block diagram of a wireless communication device according to an embodiment of the present disclosure is illustrated.

[0017] Figure 2 is a diagram illustrating an exemplary structure of a WLAN system to which the present disclosure can be applied.

[0018] Figure 3 It is a diagram for explaining a link establishment process to which the present disclosure can be applied.

[0019] Figure 4 This is a diagram for explaining a backoff process to which the present disclosure can be applied.

[0020] Figure 5 It is a diagram for explaining a frame transmission operation based on CSMA / CA to which the present disclosure can be applied.

[0021] Figure 6 is a diagram for explaining an example of a frame structure used in a WLAN system to which the present disclosure can be applied.

[0022] Figure 7 is a diagram illustrating an example of a PPDU defined in the IEEE 802.11 standard to which the present disclosure can be applied.

[0023] Figure 8 This is a diagram for explaining various transmission or reception techniques in a MAP environment to which the present disclosure can be applied.

[0024] Fig. 9 is a diagram for illustrating an example of individual TWT operations to which the present disclosure can be applied.

[0025] Fig.10 is a diagram for illustrating an example of a broadcast TWT operation to which the present disclosure can be applied.

[0026] Fig.11 is a diagram illustrating an exemplary format of a silence element and an exemplary format of a silent channel element to which the present disclosure can be applied.

[0027] Fig.12 is a diagram for explaining an example of an operation of an STA based on a silent channel according to the present disclosure.

[0028] Fig.13 is a diagram for explaining an example of an operation of an AP based on a silent channel according to the present disclosure.

[0029] Figures 14 to 20 is a diagram for explaining various examples of operations based on silent channels according to the present disclosure. DETAILED DESCRIPTION

[0030] Hereinafter, embodiments according to the present disclosure will be described in detail with reference to the accompanying drawings. The detailed description disclosed by the accompanying drawings is intended to describe exemplary embodiments of the present disclosure, rather than to represent the only embodiment in which the present disclosure can be implemented. The following detailed description includes specific details to provide a complete understanding of the present disclosure. However, those skilled in the relevant art know that the present disclosure can be implemented without these specific details.

[0031] In some cases, well-known structures and devices may be omitted, or may be shown in the form of a block diagram based on the core functions of each structure and device in order to prevent ambiguity of the concepts of the present disclosure.

[0032] In the present disclosure, when an element is referred to as being "connected", "combined" or "linked" to another element, it may include an indirect connection relationship between another element and a direct connection relationship. In addition, in the present disclosure, the term "comprising" or "having" specifies the presence of the mentioned features, steps, operations, components and / or elements, but does not exclude the presence or addition of one or more other features, stages, operations, components, elements and / or groups thereof.

[0033] In the present disclosure, terms such as "first", "second", etc. are only used to distinguish one element from another element and are not used to limit the elements, and unless otherwise specified, they do not limit the order or importance between the elements, etc. Therefore, within the scope of the present disclosure, the first element in an embodiment may be referred to as the second element in another embodiment, and similarly, the second element in an embodiment may be referred to as the first element in another embodiment.

[0034] The terms used in this disclosure are intended to describe specific embodiments, rather than to limit the claims. As used in the description of the 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" used in this disclosure may refer to one of the related enumerated items, or mean that it refers to and includes any and all possible combinations of two or more of them. In addition, unless otherwise stated, the " / " between words in this disclosure has the same meaning as "and / or".

[0035] Examples of the present disclosure can be applied to various wireless communication systems. For example, examples of the present disclosure can be applied to wireless LAN systems. For example, examples of the present disclosure can be applied to wireless LANs based on IEEE 802.11a / g / n / ac / ax standards. In addition, examples of the present disclosure can be applied to wireless LANs based on the newly proposed IEEE 802.11be (or EHT) standard. Examples of the present disclosure can be applied to wireless LANs based on the IEEE802.11be version 2 standard corresponding to the additional enhanced technology of the IEEE 802.11be version 1 standard. In addition, examples of the present disclosure can be applied to wireless LANs based on next-generation standards after IEEE 802.11be. In addition, examples of the present disclosure can be applied to cellular wireless communication systems. For example, it can be applied to cellular wireless communication systems based on long-term evolution (LTE) technology and 5G new radio (NR) technology based on the third generation partnership project (3GPP) standard.

[0036] Hereinafter, technical features of examples to which the present disclosure can be applied will be described.

[0037] Figure 1 A block diagram of a wireless communication device according to an embodiment of the present disclosure is illustrated.

[0038] Figure 1The first device 100 and the second device 200 illustrated in the figure may be replaced with various terms such as terminal, wireless device, wireless transmit / receive 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 simple user, etc. In addition, the first device 100 and the second device 200 include an access point (AP), a base station (BS), a fixed station, a node B, a base transceiver system (BTS), a network. It may be replaced with various terms such as an artificial intelligence (AI) system, a roadside unit (RSU), a repeater, a router, a relay and a gateway.

[0039] Figure 1 The devices 100 and 200 illustrated in the example may be referred to as stations (STAs). Figure 1 The devices 100 and 200 illustrated in the figure may be referred to by various terms such as a transmitting device, a receiving device, a transmitting STA, and a receiving STA. For example, the STAs 110 and 200 may perform an access point (AP) role or a non-AP role. That is, in the present disclosure, the STAs 110 and 200 may perform the functions of an AP and / or a non-AP. When the STAs 110 and 200 perform the AP function, they may be simply referred to as APs, and when the STAs 110 and 200 perform the non-AP function, they may be simply referred to as STAs. In addition, in the present disclosure, an AP may also be indicated as an AP STA.

[0040] Reference Figure 1 , the first device 100 and the second device 200 can send and receive radio signals through various wireless LAN technologies (e.g., IEEE802.11 series). The first device 100 and the second device 200 may include interfaces for a media access control (MAC) layer and a physical layer (PHY) that conform to the IEEE802.11 standard.

[0041] In addition, in addition to the wireless LAN technology, the first device 100 and the second device 200 may further support various communication standards (e.g., 3GPP LTE series, 5G NR series standards, etc.) technologies. In addition, the device of the present disclosure may be implemented in various devices such as mobile phones, vehicles, personal computers, augmented reality (AR) devices, and virtual reality (VR) devices. In addition, the STA of the present specification may support various communication services such as voice calls, video calls, data communications, autonomous driving, machine type communications (MTC), machine to machine (M2M), device to device (D2D), IoT (Internet of Things), etc.

[0042] The first device 100 may include one or more processors 102 and one or more memories 104, and may further include one or more transceivers 106 and / or one or more antennas 108. The processor 102 may control the memory 104 and / or the transceiver 106, and may be configured to implement the descriptions, functions, processes, suggestions, methods, and / or operational flowcharts included in the present disclosure. For example, the processor 102 may send a wireless signal including the first information / signal through the transceiver 106 after generating the first information / signal by processing the information in the memory 104. In addition, the processor 102 may receive a wireless signal including the second information / signal through the transceiver 106, and then store the information obtained by the signal processing of the second information / signal in the memory 104. The memory 104 may be connected to the processor 102 and may store various information related to the operation of the processor 102. For example, the memory 104 may store software codes including instructions for executing all or part of the processing controlled by the processor 102 or for executing the descriptions, functions, processes, suggestions, methods, and / or operational flowcharts included in the present disclosure. Here, the processor 102 and the memory 104 may be part of a communication modem / circuit / chip designed to implement wireless LAN technology (e.g., IEEE 802.11 series). The transceiver 106 may be connected to the processor 102 and may send and / or receive wireless signals through one or more antennas 108. The transceiver 106 may include a transmitter and / or a receiver. The transceiver 106 may be used in conjunction with an RF (radio frequency) unit. In the present disclosure, a wireless device may refer to a communication modem / circuit / chip.

[0043] The second device 200 may include one or more processors 202 and one or more memories 204, and may further include one or more transceivers 206 and / or one or more antennas 208. The processor 202 may control the memory 204 and / or the transceiver 206, and may be configured to implement the descriptions, functions, processes, suggestions, methods, and / or operation flowcharts included in the present disclosure. For example, the processor 202 may generate third information / signals by processing the information in the memory 204, and then send a wireless signal including the third information / signal through the transceiver 206. In addition, the processor 202 may receive a wireless signal including fourth information / signals through the transceiver 206, and then store information obtained by signal processing of the fourth information / signal in the memory 204. The memory 204 may be connected to the processor 202 and may store various information related to the operation of the processor 202. For example, the memory 204 may store software codes including instructions for executing all or part of the processing controlled by the processor 202 or for executing the descriptions, functions, processes, suggestions, methods, and / or operation flowcharts included in the present disclosure. Here, the processor 202 and the memory 204 may be part of a communication modem / circuit / chip designed to implement wireless LAN technology (e.g., IEEE 802.11 series). The transceiver 206 may be connected to the processor 202 and may send and / or receive wireless signals through one or more antennas 208. The transceiver 206 may include a transmitter and / or a receiver. The transceiver 206 may be used in conjunction with an RF unit. In the present disclosure, a device may refer to a communication modem / circuit / chip.

[0044] In the following, the hardware elements of the apparatus 100, 200 will be described in more detail. Without limitation thereto, one or more protocol layers may be implemented by one or more processors 102, 202. For example, one or more processors 102, 202 may implement one or more layers (e.g., functional layers such as PHY, MAC). One or more processors 102, 202 may generate one or more PDUs (protocol data units) and / or one or more SDUs (service data units) according to the description, function, process, suggestion, method, and / or operation flow chart disclosed in the present disclosure. One or more processors 102, 202 may generate messages, control information, data, or information according to the description, function, process, suggestion, method, and / or operation flow chart disclosed in the present disclosure. One or more processors 102, 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 the present disclosure to provide them to one or more transceivers 106, 206. One or more processors 102, 202 may receive a signal (e.g., a baseband signal) from one or more transceivers 106, 206 according to the descriptions, functions, processes, suggestions, methods, and / or operational flow charts included in the present disclosure and obtain a PDU, SDU, message, control information, data, or information.

[0045] 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 operational flow charts included in the present disclosure may be implemented using firmware or software, and the firmware or software may be implemented to include modules, processes, functions, and the like. Firmware or software configured to execute the descriptions, functions, processes, suggestions, methods, and / or operational flow charts included in the present 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 operational flow charts included in the present disclosure may be implemented using firmware or software in the form of codes, instructions and / or instruction sets.

[0046] One or more memories 104, 204 may be connected to one or more processors 102, 202 and may store data, signals, messages, information, programs, codes, instructions, and / or commands in various forms. One or more memories 104, 204 may be configured with ROM, RAM, EPROM, flash memory, hard drive, registers, cache memory, computer-readable storage media, and / or combinations thereof. One or more memories 104, 204 may be located inside and / or outside one or more processors 102, 202. In addition, 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.

[0047] One or more transceivers 106, 206 may send user data, control information, wireless signals / channels, etc. mentioned in the method and / or operation flow chart of the present disclosure to one or more other devices. One or more transceivers 106, 206 may receive user data, control information, wireless signals / channels, etc. mentioned in the description, function, process, suggestion, method and / or operation flow chart, etc. included in the present disclosure from one or more other devices. For example, one or more transceivers 106, 206 may be connected to one or more processors 102, 202 and may send and receive wireless signals. For example, one or more processors 102, 202 may control one or more transceivers 106, 206 to send user data, control information or wireless signals to one or more other devices. In addition, one or more processors 102, 202 may control one or more transceivers 106, 206 to receive user data, control information or wireless signals from one or more other devices. In addition, 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 send and receive user data, control information, wireless signals / channels, etc. mentioned in the description, functions, processes, suggestions, methods and / or operation flow charts, etc. included in the present disclosure through one or more antennas 108, 208. In the present 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 to process received user data, control information, wireless signals / channels, etc. by using one or more processors 102, 202. One or more transceivers 106, 206 may convert user data, control information, wireless signals / channels, etc. processed by using one or more processors 102, 202 from baseband signals into RF band signals. Thus, one or more of the transceivers 106 , 206 may include (analog) oscillators and / or filters.

[0048] For example, one of the STAs 100 and 200 may perform the expected operation of an AP, and the other of the STAs 100 and 200 may perform the expected operation of a non-AP STA. Figure 1 The transceivers 106 and 206 of the present invention may perform transmission and reception operations of signals (e.g., packets or physical layer protocol data units (PPDUs) compliant with IEEE 802.11a / b / g / n / ac / ax / be / bn). In addition, in the present disclosure, operations of various STAs generating transmission / reception signals or performing data processing or calculations on transmission / reception signals in advance may be performed by Figure 1The processors 102 and 202 are executed. For example, examples of operations of generating a transmission / reception signal or performing data processing or calculation for the transmission / reception signal in advance may include: 1) determining / obtaining / configuring / calculating / decoding / encoding bit information of fields (signal (SIG), short training field (STF), long training field (LTF), data, etc.) included in the PPDU; 2) determining / configuring / obtaining time resources or frequency resources (e.g., subcarrier resources) for fields (SIG, STF, LTF, data, etc.) included in the PPDU; 3) determining / configuring / obtaining a specific sequence (e.g., pilot sequence, STF / LTF sequence, additional sequence applied to SIG) for fields (SIG, STF, LTF, data, etc.) included in the PPDU action; 4) power control operations and / or power saving operations applied to STAs; 5) operations related to ACK signal determination / obtaining / configuring / calculating / decoding / encoding, etc. In addition, in the following example, various information used by various STAs to determine / acquire / configure / calculate / decode / encode transmission signals and reception signals (e.g., information related to fields / subfields / control fields / parameters / power, etc.) may be stored in Figure 1 in the memories 104 and 204.

[0049] Hereinafter, downlink (DL) may mean a link for communication from an AP STA to a non-AP STA, and a DL PPDU / packet / signal may be transmitted and received through the DL. In DL communication, a transmitter may be a part of an AP STA, and a receiver may be a part of a non-AP STA. An uplink (UL) may mean a link for communication from a non-AP STA to an AP STA, and an UL PPDU / packet / signal may be transmitted and received through the UL. In UL communication, a transmitter may be a part of a non-AP STA, and a receiver may be a part of an AP STA.

[0050] Figure 2 is a diagram illustrating an exemplary structure of a wireless LAN system to which the present disclosure can be applied.

[0051] The structure of the wireless LAN system may be composed of a plurality of components. A wireless LAN supporting STA mobility transparent to an upper layer may be provided through the interaction of the plurality of components. A basic service set (BSS) corresponds to a basic building block of a wireless LAN. Figure 2 It is exemplarily shown that two BSSs (BSS1 and BSS2) exist, and two STAs (STA1 and STA2 are included in BSS1, and STA3 and STA4 are included in BSS2) are included as members of each BSS. Figure 2The ellipse representing the BSS in the figure can also be understood as representing the coverage area in which the STAs included in the corresponding BSS maintain communication. This area can be called a basic service area (BSA). When a STA moves outside the BSA, it cannot communicate directly with other STAs in the BSA.

[0052] If you don't consider Figure 2 , the most basic BSS type in the wireless LAN is an independent BSS (IBSS), if the DS is shown in FIG. 1 . For example, an IBSS may have a minimum form containing only two STAs. For example, assuming that other components are omitted, a BSS1 containing only STA1 and STA2 or a BSS2 containing only STA3 and STA4 may correspond to representative examples of IBSSs, respectively. This configuration is possible when STAs can communicate directly without an AP. In addition, in this type of wireless LAN, it is not pre-configured but can be configured when a LAN is needed, and this may be referred to as an ad-hoc network. Since the IBSS does not include an AP, there is no centralized management entity. That is, in the IBSS, STAs are managed in a distributed manner. In the IBSS, all STAs may be composed of mobile STAs, and access to the distributed system (DS) is not allowed, thereby forming a self-contained network.

[0053] The membership of a STA in a BSS can be changed dynamically by turning the STA on or off, entering or exiting a BSS region, etc. In order to become a member of a BSS, a STA can join the BSS using a synchronization process. In order to access all services of the BSS infrastructure, a STA should associate with the BSS. This association can be established dynamically and can include the use of a distributed system service (DSS).

[0054] The 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 some cases, communication between STAs at longer distances may be required. A distributed system (DS) can be configured to support extended coverage.

[0055] DS refers to the structure of BSS interconnection. Specifically, Figure 2As shown, the BSS can exist as an extended form of a network composed of multiple BSSs. DS is a logical concept and can be specified by 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 different purposes and is used 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 the wireless LAN structure (DS structure or other network structure) can be interpreted as multiple media being logically different. That is, the wireless LAN structure can be implemented in various ways, and the corresponding wireless LAN structure can be independently specified by the physical characteristics of each implementation.

[0056] DS can support mobile devices by providing seamless integration of multiple BSSs and providing logical services necessary to address the address leading to the destination. In addition, DS can also include a component called a portal, which is used as a bridge for connection between wireless LAN and other networks (e.g., IEEE 802.X).

[0057] The AP enables access to the DS through the WM for associated non-AP STAs and means an entity that also has STA functionality. Data movement between the BSS and the DS can be performed through the AP. For example, Figure 2 STA2 and STA3 shown in the figure have the function of STA and provide the function of allowing the associated non-AP STA (STA1 and STA4) to access the DS. In addition, since all APs basically correspond to STAs, all APs are addressable entities. The address used by the AP to communicate on the WM is not necessarily the same as the address used by the AP to communicate on the DSM. A BSS composed of an AP and one or more STAs may be referred to as an infrastructure BSS.

[0058] Data sent from one of the STAs associated with the AP to the STA address of the corresponding AP can always be received at the uncontrolled port and can be processed by the IEEE 802.1X port access entity. In addition, when the controlled port is authenticated, the transmitted data (or frame) can be delivered to the DS.

[0059] In addition to the above-mentioned structure of the DS, an extended service set (ESS) may also be configured to provide wide coverage.

[0060] ESS means a network with arbitrary size and complexity consisting of DS and BSS. ESS may correspond to a set of BSSs connected to one DS. However, ESS does not include DS. The ESS network is characterized by being regarded as an IBSS in the logical link control (LLC) layer. The STAs included in the ESS can communicate with each other, and the mobile STA can move from one BSS to another (within the same ESS) transparently for LLC. The APs included in one ESS may have the same service set identifier (SSID). SSID is distinguished from BSSID, which is an identifier of BSS.

[0061] The wireless LAN system does not assume anything about the relative physical location of the BSS, and all of the following forms are possible. The BSS may partially overlap, which is a form commonly used to provide continuous coverage. In addition, the BSS may not be physically connected, and logically, there is no limit on the distance between the BSS. In addition, the BSS may be physically located in the same location, which can be used to provide redundancy. In addition, one (or more than one) IBSS or ESS network may physically exist in the same space as one (or more than one) ESS network. 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, this may correspond to the form of an ESS network, etc.

[0062] Figure 3 is a diagram for explaining a link establishment process to which the present disclosure can be applied.

[0063] In order for a STA to establish a link with respect to a network and send / receive data, it first discovers the network, performs authentication, establishes association, and needs to perform authentication processing for security. The link establishment processing may also be referred to as a session initiation processing or a session establishment processing. In addition, the discovery, authentication, association, and security establishment processing of the link establishment processing may be collectively referred to as an association processing.

[0064] In step S310, the STA may perform a network discovery operation. The network discovery operation may include a scanning operation of the STA. That is, in order for the STA to access a network, it needs to find a network that it can participate in. The STA should identify compatible networks before participating in a wireless network, and the process of identifying networks present in a specific area is called scanning.

[0065] Scanning schemes include active scanning and passive scanning. Figure 3The network discovery operation including active scanning processing is exemplarily illustrated. In active scanning, the STA performing the scan sends a probe request frame to discover which APs exist around it while the channel moves and waits for a response thereto. The responder sends a probe response frame as a response to the probe request frame to the STA that has 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, since the AP sends a beacon frame, the AP becomes the responder, and in the IBSS, the STAs in the IBSS rotate to send beacon frames, so the responder is not constant. For example, a 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 scanning in the same manner (i.e., sending and receiving probe requests / responses on channel 2).

[0066] Although not in Figure 3 , but the scanning operation can be performed in a passive scanning manner. In passive scanning, the STA performing the scan waits for a beacon frame while the channel moves. The beacon frame is one of the management frames defined in IEEE 802.11, and is periodically sent to notify the existence of a wireless network and allow the STA performing the scan to find the wireless network and participate in the wireless network. In the BSS, the AP is used to periodically send beacon frames, and in the IBSS, the STAs within the IBSS rotate to send beacon frames. When the STA performing the scan receives the beacon frame, the STA stores the information of the BSS included in the beacon frame, and records the beacon frame information in 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 scanning with passive scanning, the advantage of active scanning is that it has less delay and less power consumption than passive scanning.

[0067] After the STA discovers the network, an authentication process may be performed at step S320. In order to clearly distinguish from the security establishment operation of step S340 to be described later, this authentication process may be referred to as a first authentication process.

[0068] The authentication process includes the following process: the STA sends an authentication request frame to the AP, and in response thereto, the AP sends an authentication response frame to the STA. The authentication frame for authentication request / response corresponds to a management frame.

[0069] The authentication frame includes an authentication algorithm number, an authentication transaction sequence number, a status code, a challenge text, a robust security network (RSN), a limited cycle group, etc. This corresponds 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 can also be included.

[0070] The STA may send an authentication request frame to the AP. The AP may determine whether to allow authentication of the corresponding STA based on the information included in the received authentication request frame. The AP may provide the result of the authentication process to the STA via an authentication response frame.

[0071] After the STA is successfully authenticated, an association process may be performed at step S330. The association process includes the following processes: the STA sends an association request frame to the AP, and in response, the AP sends an association response frame to the STA.

[0072] For example, the association request frame may include information related to various capabilities, a beacon listening interval, a service set identifier (SSID), supported rates, supported channels, RSN, a mobile domain, supported operation categories, a traffic indication map broadcast request (TIM broadcast request), interworking service capabilities, etc. For example, the association response frame may include information related to various capabilities, a status code, an association ID (AID), supported rates, an enhanced distributed channel access (EDCA) parameter set, a received channel power indicator (RCPI), a received signal-to-noise ratio indicator (RSNI), a mobile domain, a timeout interval (e.g., an association recovery time), an overlapping BSS scan parameter, a TIM broadcast response, a quality of service (QoS) map, etc. This corresponds to some examples of information that may be included in an association request / response frame, and may be replaced with other information, or may also include additional information.

[0073] After the STA successfully associates with the network, a security establishment process may be performed at step S340. The security establishment process at step S340 may be referred to as an authentication process through a robust security network association (RSNA) request / response, the authentication process at step S320 may be referred to as a first authentication process, and the security establishment process at step S340 may also be referred to simply as an authentication process.

[0074] The security establishment process of step S340 may include, for example, a process of establishing a private key through an Extensible Authentication Protocol over LAN (EAPOL) frame using a four-way handshake. In addition, the security establishment process may be performed according to a security scheme not defined in the IEEE 802.11 standard.

[0075] Figure 4 It is a diagram for explaining a backoff process to which the present disclosure can be applied.

[0076] In a wireless LAN system, the basic access mechanism of the medium access control (MAC) is a carrier sense multiple access with collision avoidance (CSMA / CA) mechanism. The CSMA / CA mechanism is also known as the distributed coordination function (DCF) of the IEEE 802.11 MAC, and basically adopts a "listen before talk" access mechanism. According to this type of access mechanism, before starting to send, the AP and / or STA may perform a clear channel assessment (CCA) of sensing the radio channel or medium during a predetermined time interval (e.g., DCF interframe space (DIFS)). As a result of the sensing, if it is determined that the medium is in an idle state, frame transmission is started through the corresponding medium. On the other hand, if it is detected that the medium is occupied or busy, the corresponding AP and / or STA does not start its own transmission, and a delay period (e.g., a random backoff period) for medium access may be set and frame transmission may be attempted after waiting. By applying a random backoff period, since multiple STAs are expected to attempt frame transmission after waiting for different time periods, conflicts can be minimized.

[0077] 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 synchronous access method based on polling, and refers to a method in which all receiving APs and / or STAs periodically poll to receive data frames. In addition, HCF has enhanced distributed channel access (EDCA) and HCF controlled channel access (HCCA). EDCA is a contention-based access method that provides data frames to multiple users in a direction, and HCCA uses a non-contention-based channel access method that utilizes a polling mechanism. In addition, HCF includes a medium access mechanism for improving the QoS (quality of service) of a wireless LAN, and QoS data can be sent during a contention period (CP) and a contention-free period (CFP).

[0078] Reference Figure 4, the operation based on the random backoff period will be described. When the occupied / busy medium becomes idle, multiple STAs may attempt to send data (or frames). As a method of minimizing conflicts, each of the STAs may select a random backoff count respectively and attempt to send after waiting for the corresponding time slot time. The random backoff count has a pseudo-random integer value and may be determined as one of the values ​​ranging from 0 to CW. Here, CW is a contention window parameter value. The CW parameter is assigned CWmin as an initial value, but may take a value twice as large in the event of a transmission failure (e.g., when an ACK for a transmitted frame is not received). When the CW parameter value reaches CWmax, data transmission may be attempted while maintaining the CWmax value until data transmission is successful, and when data transmission is successful, the CWmin value is reset. The values ​​of CW, CWmin, and CWmax are preferably set to 2n-1 (n=0, 1, 2, ...).

[0079] When the random backoff process starts, the STA continuously monitors the medium in the backoff slot countdown according to the determined backoff count value. When the medium is monitored for occupancy, it stops the countdown and waits, and restarts the remaining part of the countdown when the medium becomes idle.

[0080] exist Figure 4 In the example of , when the packet to be sent arrives at the MAC of STA3, STA3 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. At the same time, the data to be sent can also occur in each of STA1, STA2 and STA5, and when the medium is monitored as idle, each STA waits for up to DIFS, and then the countdown of the backoff slot can be performed according to the random backoff count value selected by each STA. Assume that STA2 selects the minimum backoff count value and STA1 selects the maximum backoff count value. That is, the example illustrates a case where the remaining backoff time of STA5 is shorter than the remaining backoff time of STA1 when STA2 completes the backoff count and starts frame transmission. STA1 and STA5 temporarily stop the countdown and wait when STA2 occupies the medium. When STA2's occupancy ends and the medium becomes idle again, STA1 and STA5 wait for DIFS and restart the stopped backoff count. That is, frame transmission can start after counting down the remaining backoff slot for the remaining backoff time. Since the remaining backoff time of STA5 is shorter than that of STA1, STA5 starts frame transmission. The data to be transmitted may also occur in STA4 while STA2 occupies the medium. From the perspective of STA4, when the medium becomes idle, STA4 may wait for DIFS, and then may perform a countdown according to a random backoff count value selected by STA4, and start transmitting frames. Figure 4The example shows a case where the remaining backoff time of STA5 accidentally collides 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 case, STA4 and STA5 can double the CW value, select a random backoff count value, and perform a countdown. While the medium is occupied due to the transmission of STA4 and STA5, STA1 waits, and when the medium becomes idle, STA1 waits DIFS, and then starts frame transmission after the remaining backoff time has passed.

[0081] As in Figure 4 In the example of , a data frame is a frame for sending data forwarded to a higher layer, and may be sent after a backoff performed after DIFS has passed since the medium became idle. In addition, a management frame is a frame for exchanging management information that is not forwarded to a higher layer, and is sent after a backoff is performed after an IFS such as DIFS or a point coordination function IFS (PIFS). As subtype frames of the management frame, there are beacons, association requests / responses, reassociation requests / responses, probe requests / responses, authentication requests / responses, and the like. A control frame is a frame for controlling access to a medium. As subtype frames of the control frame, there are request to send (RTS), clear to send (CTS), acknowledgement (ACK), power save poll (PS-Poll), block ACK (BlockAck), block ACK request (BlockACKReq), empty data packet announcement (NDP announcement), and trigger, and the like. If the control frame is not a response frame of the previous frame, it is sent after a backoff is performed after DIFS has passed, and if it is a response frame of the previous frame, it is sent without performing a backoff after a short IFS (SIFS). The type and subtype of a frame may be identified by the type field and subtype field in the frame control (FC) field.

[0082] Quality of Service (QoS) STA can perform a backoff performed after arbitration IFS (AIFS) (i.e., AIFS (where i is a value determined by AC)) for the access category (AC) to which the frame belongs, and then can send the frame. Here, the frame that can use AIFS may be a data frame, a management frame, or a control frame instead of a response frame.

[0083] Figure 5 is a diagram for explaining a frame transmission operation based on CSMA / CA to which the present disclosure can be applied.

[0084] As described above, in addition to the physical carrier sensing in which the STA directly senses the medium, the CSMA / CA mechanism also includes virtual carrier sensing. Virtual carrier sensing is intended to compensate for problems such as hidden node problems that may occur in medium access. For virtual carrier sensing, the MAC of the STA can use a network allocation vector (NAV). NAV is a value that indicates to other STAs the remaining time until the medium is available for use by the STA that is currently using or has the right to use the medium. Therefore, the 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, the STA receiving the NAV value is prohibited from accessing the medium. For example, the NAV can be configured based on the value of the "Duration" field of the MAC header of the frame.

[0085] exist Figure 5 In the example of FIG. 1 , it is assumed that STA1 intends to send data to STA2, and STA3 is in a position to be able to eavesdrop on some or all frames sent and received between STA1 and STA2.

[0086] In order to reduce the possibility of transmission conflicts among multiple STAs in the CSMA / CA-based frame transmission operation, a mechanism using RTS / CTS frames can be applied. Figure 5 In the example of , when STA1's transmission is being performed, as a result of STA3's carrier sensing, it can be determined that the medium is in an idle state. That is, STA1 may correspond to a hidden node with respect to STA3. Alternatively, in Figure 5 In the example of , it can be determined that the carrier sensing result medium of STA3 is in an idle state while the transmission of STA2 is being performed. That is, STA2 may 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 one of STA1 or STA2 or STAs outside the carrier sensing range of the transmission from STA1 or STA3 may not attempt to occupy the channel during data transmission and reception between STA1 and STA2.

[0087] Specifically, STA1 can determine whether the channel is being used by carrier sensing. In terms of physical carrier sensing, STA1 can determine the channel occupancy idle state based on the energy level or signal correlation detected in the channel. In addition, in terms of virtual carrier sensing, STA1 can use the network allocation vector (NAV) timer to determine the channel occupancy state.

[0088] When the channel is in an idle state during DIFS, STA1 may send an RTS frame to STA2 after performing backoff. When STA2 receives the RTS frame, STA2 may send a CTS frame to STA1 as a response to the RTS frame after SIFS.

[0089] If STA3 cannot eavesdrop on the CTS frame from STA2 but can eavesdrop on the RTS frame from STA1, STA3 can set the NAV timer for the frame transmission period (e.g., SIFS+CTS frame+SIFS+data frame+SIFS+ACK frame) that is continuously transmitted thereafter using the duration information included in the RTS frame. Alternatively, if STA3 can eavesdrop on the CTS frame from STA2, STA3 can set the NAV timer for the frame transmission period (e.g., SIFS+data frame+SIFS+ACK frame) that is continuously transmitted thereafter using the duration information included in the CTS frame even though STA3 cannot eavesdrop on the RTS frame from STA1. That is, if STA3 can eavesdrop on one or more of the RTS frame or the CTS frame from one or more of STA1 or STA2, STA3 can set the NAV accordingly. When STA3 receives a new frame before the NAV timer expires, STA3 can update the NAV timer using the duration information included in the new frame. STA3 does not attempt channel access until the NAV timer expires.

[0090] When STA1 receives a CTS frame from STA2, STA1 may send a data frame to STA2 after SIFS, starting from the time point when reception of the CTS frame is completed. When STA2 successfully receives the data frame, STA2 may send an ACK frame to STA1 after SIFS as a response to the data frame. When the NAV timer expires, STA3 may determine whether the channel is being used by carrier sensing. When STA3 determines that the channel is not being used by other terminals during the DIFS period after the NAV timer expires, STA3 may attempt channel access after the contention window (CW) according to the random backoff has passed.

[0091] Figure 6 is a diagram for explaining an example of a frame structure used in a WLAN system to which the present disclosure can be applied.

[0092] With the help of instructions or primitives (meaning a set of instructions or parameters) from the MAC layer, the PHY layer can prepare a MAC PDU (MPDU) to be transmitted. For example, when a command requesting the PHY layer to start transmitting is received from the MAC layer, the PHY layer switches to a transmission mode, and configures information (e.g., data) provided from the MAC layer in the form of a frame and transmits it. In addition, when the PHY layer detects a valid preamble of a received frame, the PHY layer monitors the header of the preamble and transmits a command notifying the start of reception of the PHY layer to the MAC layer.

[0093] In this manner, information transmission / reception in the wireless LAN system is performed in the form of a frame, and for this purpose, a PHY layer protocol data unit (PPDU) format is defined.

[0094] The basic PPDU may include a short training field (STF), a long training field (LTF), a signal (SIG) field, and a data (Data) field. The most basic PPDU format (e.g., Figure 7 The non-HT (high throughput) shown in the figure may consist of only the legacy-STF (L-STF), the legacy-LTF (L-LTF), the legacy-SIG (L-SIG) field and the data field. In addition, depending on the type of PPDU format (e.g., HT mixed format PPDU, HT greenfield format PPDU, VHT (very high throughput) PPDU, etc.), additional (or different types of) RL-SIG, U-SIG, non-legacy SIG field, non-legacy STF, non-legacy LTF (i.e., xx-SIG, xx-STF, xx-LTF (e.g., xx is HT, VHT, HE, EHT, etc.)) and the like may be included between the L-SIG field and the data field.

[0095] STF is a signal used for signal detection, automatic gain control (AGC), diversity selection, precise time synchronization, etc., and LTF is a signal used for channel estimation and frequency error estimation. STF and LTF can be called signals for synchronization and channel estimation of the OFDM physical layer.

[0096] The SIG field may include various information related to the transmission and reception of the PPDU. For example, the L-SIG field consists of 24 bits, and the L-SIG field may 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 may include information about the modulation and coding rate of the data. For example, the 12-bit length field may include information about the length or duration of the PPDU. For example, the value of the 12-bit length field may be determined based on the type of the PPDU. For example, for non-HT, HT, VHT, or EHT PPDUs, the value of the length field may be determined as a multiple of 3. For example, for HEPPDUs, the value of the length field may be determined as a multiple of 3+1 or a multiple of 3+2.

[0097] The data field may include a service (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 may be used for synchronization of the descrambler at the receiving end. 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 may be used to return the encoder to the 0 state. The padding bit may be used to adjust the length of the data field in predetermined units.

[0098] MAC PDU is 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). A MAC frame may consist of a MAC PDU and be transmitted / received through a PSDU of a data portion of a PPDU format.

[0099] The MAC header includes a frame control field, a duration / ID field, an address field, etc. The frame control field may include control information required for frame transmission / reception. The duration / ID field may be set to the time for transmitting the corresponding frame, etc. For details of the sequence control, QoS control, and HT control subfields of the MAC header, refer to the IEEE 802.11 standard document.

[0100] The null data PPDU (NDP) format refers to a PPDU format that does not include a data field. In other words, NDP refers to a frame format that includes a PPDU preamble (i.e., L-STF, L-LTF, L-SIG fields and additional non-legacy SIG, non-legacy STF, non-legacy LTF (if present)) of a general PPDU format and does not include the remaining part (i.e., the data field).

[0101] Figure 7 is a diagram illustrating an example of a PPDU defined in the IEEE 802.11 standard to which the present disclosure can be applied.

[0102] In standards such as IEEE 802.11a / g / n / ac / ax, various types of PPDUs have been used. The basic PPDU format (IEEE 802.11a / g) includes L-LTF, L-STF, L-SIG, and data fields. The basic PPDU format may also be referred to as a non-HT PPDU format (such as Figure 7 (as shown in (a)).

[0103] Compared to the basic PPDU format, the HT PPDU format (IEEE 802.11n) additionally includes HT-SIG, HT-STF, and HT-LFT fields. Figure 7The HT PPDU format shown in (b) may be referred to as an HT mixed format. In addition, an HT greenfield format PPDU may be defined, and this corresponds to a format consisting of HT-GF-STF, HT-LTF1, HT-SIG, one or more HT-LTFs, and a data field, excluding L-STF, L-LTF, and L-SIG (not shown).

[0104] Compared to the basic PPDU format, an example of the VHT PPDU format (IEEE 802.11ac) additionally includes VHTSIG-A, VHT-STF, VHT-LTF, and VHT-SIG-B fields (eg, Figure 7 (as shown in (c)).

[0105] Compared to the basic PPDU format, an example of the HE PPDU format (IEEE 802.11ax) additionally includes a repeated L-SIG (RL-SIG), HE-SIG-A, HE-SIG-B, HE-STF, HE-LTF, a packet extension (PE) field (such as Figure 7 (d) of the HE PPDU format). Some fields may be excluded or their lengths may vary according to the detailed example of the HE PPDU format. For example, the HE-SIG-B field is included in the HE PPDU format for multi-user (MU), and the HE-SIG-B is not included in the HE PPDU format for single user (SU). In addition, the HE trigger-based (TB) PPDU format does not include the HE-SIG-B, and the length of the HE-STF field may vary to 8μs. 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 may vary to 16μs. For example, the RL-SIG may be configured to be the same as the L-SIG. Based on the presence of the RL-SIG, the receiving STA may know that the received PPDU is a HE PPDU or an EHT PPDU, which will be described later.

[0106] The EHT PPDU format may include Figure 7 (e) EHT MU (multi-user) and Figure 7 The EHT TB (trigger-based) PPDU in (f) of FIG. The EHT PPDU format is similar to the HE PPDU format in that it includes the RL-SIG following the L-SIG, but may include the U (Universal)-SIG, the EHT-SIG, the EHT-STF, and the EHT-LTF following the RL-SIG.

[0107] Figure 7The EHT MU PPDU in (e) 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 transmission and MU transmission. For example, the EHT MU PPDU can correspond to a PPDU for one receiving STA or multiple receiving STAs.

[0108] Compared with EHT MU PPDU, Figure 7 The EHT TB PPDU in (f) omits the EHT-SIG. A STA that receives a trigger for ULMU transmission (eg, a trigger frame or a triggered response schedule (TRS)) may perform UL transmission based on the EHT TB PPDU format.

[0109] The L-STF, L-LTF, L-SIG, RL-SIG, U-SIG (Universal Signal), EHT-SIG fields may be coded and modulated so that even legacy STAs may attempt to demodulate and decode, and may be mapped based on a determined subcarrier frequency interval (e.g., 312.5kHz). These may be referred to as pre-EHT modulation fields. Next, the EHT-STF, EHT-LTF, data, PE fields may be coded and modulated so that they may be demodulated and decoded by a STA that successfully decodes a non-legacy SIG (e.g., U-SIG and / or EHT-SIG) and obtains the information included in the field, and may be mapped based on a determined subcarrier frequency interval (e.g., 78.125kHz). These may be referred to as EHT modulation fields.

[0110] Similarly, in the HE PPDU format, the L-STF, L-LTF, L-SIG, RL-SIG, HE-SIG-A, and HE-SIG-B fields may be referred to as pre-HE modulation fields, and the HE-STF, HE-LTF, data, and PE fields may be referred to as HE modulation fields. In addition, in the VHT PPDU format, the L-STF, L-LTF, L-SIG, and VHT-SIG-A fields may be referred to as non-VHT modulation fields, and the VHT STF, VHT-LTF, VHT-SIG-B, and data fields may be referred to as VHT modulation fields.

[0111] Included in Figure 7The U-SIG in the EHT PPDU format may be configured based on, for example, two symbols (e.g., two consecutive OFDM symbols). Each symbol (e.g., OFDM symbol) used for the U-SIG may have a duration of 4 μs, and the U-SIG may have a total duration of 8 μs. Each symbol of the U-SIG may be used to send 26 bits of information. For example, each symbol of the U-SIG may be sent and received based on 52 data tones and 4 pilot tones.

[0112] The U-SIG may be constructed in units of 20 MHz. For example, if an 80 MHz PPDU is constructed, the U-SIG may be duplicated. That is, the same 4 U-SIGs may be included in the 80 MHz PPDU. A PPDU with a bandwidth exceeding 80 MHz may include a different U-SIG.

[0113] For example, A uncoded bits may be sent via U-SIG, the first symbol of U-SIG (e.g., U-SIG-1 symbol) may send the first X bits of information out of a total of A bits of information, and the second symbol of U-SIG (e.g., U-SIG-2 symbol) may send the remaining Y bits of information out of a total of A bits of information. The A bits of information (e.g., 52 uncoded bits) may include a CRC field (e.g., a 4-bit long field) and a tail field (e.g., a 6-bit long field). For example, the tail field may be used to terminate the trellis structure of the convolutional decoder and may be set to 0.

[0114] The bit information sent through U-SIG can be divided into version-independent bits and version-dependent bits. For example, U-SIG can be included in Figure 7 In a new PPDU format not shown in the EHT PPDU format (e.g., UHR PPDU format), and may be included in the format of the U-SIG field included in the EHT PPDU format and the format of the U-SIG field included in the UHR PPDU format, the version-independent bits may be the same, and some or all of the version-related bits may be different.

[0115] For example, the size of the version-independent bit of the U-SIG may be fixed or variable. The version-independent bit may be assigned only to the U-SIG-1 symbol, or to both the U-SIG-1 symbol and the U-SIG-2 symbol. The version-independent bit and the version-dependent bit may be referred to by various names, such as a first control bit and a second control bit.

[0116] For example, the version-independent bits of the U-SIG may include a 3-bit physical layer version identifier (PHY version identifier), and this information may indicate the PHY version (e.g., EHT, UHR, etc.) of the transmitted / received PPDU. The version-independent bits of the 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 of the UL / DL flag field is related to DL communication. The version-independent bits of the U-SIG may include information about the length of a transmit opportunity (TXOP) and information about a BSS color ID.

[0117] For example, the version-related bits of the U-SIG may include information directly or indirectly indicating the type of the PPDU (eg, SU PPDU, MU PPDU, TB PPDU, etc.).

[0118] Information required for PPDU transmission and reception may be included in the U-SIG. For example, the U-SIG may also include information about bandwidth, information about an MCS technology applied to a non-legacy SIG (e.g., EHT-SIG or UHR-SIG, etc.), information indicating whether a DCM (dual carrier modulation) technology (e.g., a technology for achieving an effect similar to frequency diversity by reusing the same signal on two subcarriers) is applied to the non-legacy SIG, information about the number of symbols used for the non-legacy SIG, and information about whether the non-legacy SIG is generated across the entire frequency band.

[0119] Some of the information required for PPDU transmission and reception may be included in the U-SIG and / or the non-legacy SIG (e.g., EHT-SIG or UHR-SIG, etc.). For example, information about the type of non-legacy LTF / STF (e.g., EHT-LTF / EHT-STF or UHR-LTF / UHR-STF, etc.), information about the length of the non-legacy LTF and the CP (cyclic prefix) length, information about the GI (guard interval) applicable to the non-legacy LTF, information about preamble puncturing applicable to the PPDU, information about resource unit (RU) allocation, etc. may be included only in the U-SIG, only in the non-legacy SIG, or may be indicated by a combination of information included in the U-SIG and information included in the non-legacy SIG.

[0120] Preamble puncturing may indicate the transmission of a PPDU in which there is no signal in one or more frequency units in the bandwidth of the PPDU. For example, the size of the frequency unit (or the resolution of the preamble puncturing) may be defined as 20 MHz, 40 MHz, etc. For example, preamble puncturing may be applied to a PPDU bandwidth of a predetermined size or greater.

[0121] exist Figure 7In the example of , non-legacy SIGs such as HE-SIG-B and EHT-SIG may include control information for receiving STAs. The non-legacy SIG may be transmitted on at least one symbol, and one symbol may have a length of 4 μs. Information about the number of symbols used for the EHT-SIG may be included in a previous SIG (eg, HE-SIG-A, U-SIG, etc.).

[0122] Non-legacy SIGs such as HE-SIG-B and EHT-SIG may include a common field and a user-specific field. The common field and the user-specific field may be encoded separately.

[0123] In some cases, the common field may be omitted. For example, in a compressed mode that does not apply OFDMA (Orthogonal Frequency Division Multiple Access), the common field may be omitted, and multiple STAs may receive the PPDU (e.g., the data field of the PPDU) through the same frequency band. In a non-compressed mode that applies OFDMA, multiple users may receive the PPDU (e.g., the data field of the PPDU) through different frequency bands.

[0124] The number of user-specific fields may be determined based on the number of users. A user block field may include up to two user fields. Each user field may be associated with a MU-MIMO allocation or may be associated with a non-MU-MIMO allocation.

[0125] The common field may include a CRC bit and a tail bit, and the length of the CRC bit may be determined to be 4 bits, and the length of the tail bit may be determined to be 6 bits and set to 000000. The common field may include RU allocation information. The RU allocation information may include information about the positions of RUs to which multiple users (ie, multiple receiving STAs) are assigned.

[0126] RU can include multiple subcarriers (or tones). RU can be used when sending signals to multiple STAs based on OFDMA technology. In addition, RU can be defined even when sending signals to one STA. Resources can be allocated to non-traditional STF, non-traditional LTF and data fields in units of RU.

[0127] The RU of applicable size may be defined according to the PPDU bandwidth. The RU may be defined identically or differently for the applied PPDU format (e.g., HEPPDU, EHT PPDU, UHR PPDU, etc.). For example, in the case of an 80MHz PPDU, the RU layout of the HEPPDU and EHT PPDU may be different. The applicable RU size, the number of RUs and RU positions, the DC (direct current) subcarrier positions and numbers, the empty subcarrier positions and numbers, the guard subcarrier positions and numbers, etc. for each PPDU bandwidth may be referred to as a tone plan. For example, a tone plan for high bandwidth may be defined in the form of multiple iterations of a low bandwidth tone plan.

[0128] RUs of various sizes may 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 (multi-RUs) are different from multiple individual RUs and correspond to a group of subcarriers consisting of multiple RUs. For example, one MRU may 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. In addition, the multiple RUs constituting one MRU may or may not be continuous in the frequency domain.

[0129] The specific size of the RU may be reduced or expanded. Therefore, the specific size of each RU in the present disclosure (i.e., the number of corresponding tones) is not restrictive but illustrative. In addition, in the present disclosure, within a predetermined bandwidth (e.g., 20 MHz, 40 MHz, 80 MHz, 160 MHz, 320 MHz ...), the number of RUs may vary according to the RU size.

[0130] Figure 7 The names of each field in the PPDU format are exemplary, and the scope of the present disclosure is not limited by these names. In addition, the examples of the present disclosure can be applied to Figure 7 The PPDU format shown in Figure 7 A new PPDU format that excludes some fields and / or adds some fields.

[0131] Multiple Access Point (MAP) Operation

[0132] Hereinafter, an example of the present disclosure for a multiple access point (MAP) operation will be described.

[0133] MAP operation may be defined as an operation between a master AP (or sharing AP) and a slave AP (or shared AP).

[0134] The master AP plays a role in initiating and controlling MAP operations for transmission or reception between multiple APs. The master AP groups slave APs and manages links with the slave APs to share information between the slave APs. The master AP manages information of the BSS configured with the slave APs and information of the STA associated with the corresponding BSS.

[0135] The slave AP can be associated with the master AP and share control information, management information, and data traffic with each other. The slave AP performs the basic function of an AP that can establish a BSS in a wireless LAN in the same manner.

[0136] A STA in MAP operation may associate with a slave AP or a master AP to configure a BSS.

[0137] In a MAP environment, a master AP and a slave AP may perform direct transmission or reception with each other. A master AP and a STA may not be able to perform direct transmission or reception with each other. A slave AP (e.g., a slave AP associated with a STA) may perform direct transmission or reception with a STA. One of the slave APs may become a master AP.

[0138] MAP operation is a technology in which at least one AP sends and receives information to at least one STA. For example, a coordinated-time division multiple access (C-TDMA) technology that divides allocations between APs on a time axis, a coordinated-orthogonal frequency division multiple access (C-OFDMA) technology that divides allocations between APs on a frequency axis, a coordinated-spatial reuse (C-SR) technology using spatial reuse, etc. can be applied to MAP operation. Alternatively, C-BF (coordinated beamforming) or joint beamforming technology that collaboratively performs simultaneous transmission or reception can also be applied to MAP operation.

[0139] Figure 8 This is a diagram for explaining various transmission or reception techniques in a MAP environment to which the present disclosure can be applied.

[0140] When the BSS AP performs transmission to the BSS STA as in the existing method, it can be called single transmission (STX). In STX, there is a problem that the performance of transmission or reception of users / STAs located at the edge of the cell is reduced due to interference with neighboring APs. Fig.15 In (a), when AP1 and AP2 transmit to STA1 and STA2 simultaneously in the same frequency bandwidth, a conflict may occur on the wireless medium.

[0141] In the MAP technology, performance can be improved by a method for reducing inter-symbol interference (ISI) by cooperating between adjacent APs or performing transmission together. Figure 8 In the C-OFDMA method of (b), AP1 can perform transmission to STA1 in the first bandwidth, and AP2 can perform transmission to STA2 in the second bandwidth at the same time to avoid interference. Figure 8 The example in (c) shows a collaborative beamforming or nulling technique in which AP1 nulls interference to AP2 and / or STA2 when performing transmission to STA1, and AP2 nulls interference to AP1 and / or STA1 when performing transmission to STA2. Figure 8 (d) shows an AP selection method that enables an AP with good channel conditions among neighboring APs to perform transmission. Figure 8 In the example of (e), joint transmission (JTX) or joint reception (JRX) in which multiple APs cooperate to simultaneously perform transmission or reception can be applied, and further, joint MU-MIMO can be supported.

[0142] In an example of the present disclosure, it is assumed that a multi-AP operation is performed as follows.

[0143] Step 1: Allocate a resource region to each AP through a trigger frame from a master AP (ie, an AP-to-AP trigger frame or a master trigger frame).

[0144] Step 2: Each AP performs DL (i.e., from AP to STA) data transmission in the resource region allocated to it, or sends a trigger frame (i.e., AP to STA trigger frame) for UL (i.e., from STA to AP) data transmission in the resource region allocated to it.

[0145] Step 3: The STA sends a response to the DL data, or sends it through UL data (eg, TB PPDU).

[0146] When the resources allocated between APs are frequency resources, it can correspond to the C-OFDMA method, when the resources allocated between APs are time resources, it can correspond to the C-TDMA technology, and when the resources allocated between APs are space resources (or beams), it can correspond to the CBF method. In the example described below, it is representatively described by assuming that the C-OFDMA technology is performed, that is, multi-AP operation of resources distinguished in the frequency domain. However, the scope of the present disclosure is not limited to this, and may additionally or alternatively include multi-AP operation of resources distinguished in another domain (e.g., time domain and / or spatial domain).

[0147] Target Wake Time (TWT)

[0148] Hereinafter, a target wake time (TWT) is described.

[0149] TWT is a power saving (PS) technology that can improve the energy efficiency of non-AP STAs by defining the service period (SP) between the AP and the non-AP STA and sharing information about the SP with each other to reduce medium contention. The STA that performs a request / suggestion / requirement, etc. in the TWT setup step may be referred to as a TWT requesting STA. In addition, the AP that responds to the corresponding request such as acceptance / rejection may be referred to as a TWT responding STA. The setup step may include the STA's TWT request to the AP, the type of TWT operation performed, and the process of determining / defining the type of frame sent or received. TWT operations can be divided into individual TWT and broadcast TWT.

[0150] Fig. 9 is a diagram for illustrating an example of individual TWT operations to which the present disclosure can be applied.

[0151] Individual TWT is a mechanism for the AP and non-AP STA to perform data exchange after performing negotiation on the wake-up / sleep state of the non-AP STA by sending or receiving TWT request / response frames. Fig. 9 In the example of , AP and STA1 can form a triggered TWT agreement through a TWT request frame and a TWT response frame. Here, the method used by STA1 is the solicited TWT method, which is a method in which STA1 receives information for TWT operation from AP through a TWT response frame when STA1 sends a TWT request frame to AP. On the other hand, STA2, which performs a non-solicitation TWT method, can receive information about the configuration of the triggered TWT agreement from AP through a non-solicitation TWT response. Specifically, STA2 can calculate the next TWT by adding a specific number from the current TWT value. During the triggered TWT SP, the AP can send a trigger frame to the STA. The trigger frame can notify the STA that the AP has buffered the data. In response to this, STA1 can notify the AP of its wake-up state by sending a PS-poll frame. In addition, STA2 can notify the AP of its wake-up state by sending a QoS empty frame. Here, the data frame sent by STA1 and STA2 can be a frame in the form of a TB PPDU. The AP that confirms the status of STA1 and STA2 can send a DLMU PPDU to wake up the STA. When the corresponding TWT SP expires, STA1 and STA2 can switch to a sleep state.

[0152] Fig.10 is a diagram for illustrating an example of a broadcast TWT operation to which the present disclosure can be applied.

[0153] Broadcast TWT is a TWT in which a non-AP STA (or TWT scheduling STA) obtains information about the target beacon transmission time (TBTT) and the listening interval, etc. by sending or receiving TWT request / response frames with the AP (or TWT scheduled STA). Here, a negotiation operation for TBTT can be performed. Based on this, the AP can define a frame that will include the scheduling information of the TWT through a beacon frame. Fig.10 In the broadcast TWT, STA1 performs a solicited TWT operation and STA2 performs a non-solicited TWT operation. The AP can send a DLMU PPDU after confirming the wake-up state of the STA through a trigger sent by the AP. This can be the same as the process of individual TWT. In the broadcast TWT, the triggered TWT SP including the beacon frame can be repeated several times at a certain interval.

[0154] The delivery of TWT information can be performed through TWT information frames and TWT information elements.

[0155] With the recent surge in wired and wireless services, delay-sensitive services have also increased significantly. Delay-sensitive services include real-time audio / video transmission, and with the surge in multimedia devices, the demand for supporting such services in a wireless environment has increased. However, compared with a wired environment, many things must be considered in a wireless environment to support delay-sensitive services. This is because the transmission speed in a wireless environment is lower than that in a wired environment, and interference issues from the surrounding environment must also be considered. Specifically, in a WLAN system, multiple STAs must equally compete for medium occupancy in the Industrial Scientific Medical (ISM) band, so supporting delay-sensitive services is relatively more difficult than in a cellular communication network based on radio resource scheduling by a central base station. The present disclosure describes a new method for supporting delay-sensitive services in a WLAN system.

[0156] In the present disclosure, latency may refer to latency defined in the IEEE 802.11 series of standards. For example, it may refer to the time from when a frame to be transmitted enters the queue of the MAC layer of the transmitting STA until the transmission of the transmitting STA is successfully completed in the PHY layer, and the corresponding frame is deleted from the queue of the MAC layer of the transmitting STA after the transmitting STA receives ACK / block ACK, etc. from the receiving STA. In addition, in the present disclosure, a non-AP STA that supports transmission of latency-sensitive data may be referred to as a low-latency STA. And, data other than latency-sensitive data may be referred to as regular data.

[0157] Since the AP configures a special broadcast TWT for the low-latency STA that sends latency-sensitive data, the restricted TWT (restricted TWT, r-TWT) can support ensuring that the data transmission possibility of the low-latency STA takes precedence over other STAs. The STA can establish membership for the AP for at least one r-TWT scheduling. Here, the r-TWT agreement can be established through the same process as the broadcast TWT agreement, and the broadcast TWT element used for this can be defined to include an r-TWT parameter set field. For example, the r-TWT parameter set may refer to a specific broadcast TWT parameter set field that is different from other broadcast TWT parameter set fields. In other words, the r-TWT parameter set field may correspond to a special case of the broadcast TWT parameter set field. In addition, the AP can announce the r-TWT SP.

[0158] Basically, if another STA supporting r-TWT operation is the TXOP holder, the TXOP must end before the start time of the r-TWT SP announced in the associated AP. Therefore, the STA associated with the corresponding r-TWT (i.e., the low-latency STA) can perform service transmission or reception in priority to other STAs within the r-TWT SP.

[0159] In the present disclosure, as described above, a low-latency STA associated with a specific r-TWT is referred to as a member r-TWT scheduled STA, and other STAs are referred to as non-member STAs. A non-member STA has the ability to support r-TWT operations, but it may not be a member of any r-TWT, or may support r-TWT operations and may be a member of another r-TWT, or may be a STA that does not have the ability to support r-TWT operations.

[0160] A STA (e.g., a low-latency STA) that supports restricted SP (or r-TWT SP) operation of broadcast TWT can notify the AP that delay-sensitive data must be sent based on r-TWT operation. If the AP supports r-TWT operation / mode, the AP can send a frame including scheduling information of the TWT requested by each STA to the low-latency STA and other STAs. For example, in order to perform operations for r-TWT, a non-AP STA can obtain r-TWT related information from the AP through a beacon frame, a probe response frame, a (re)association response frame, or other format frames that have not yet been defined (e.g., frames for broadcasts, notifications, and announcements).

[0161] According to the restricted TWT operation, a separate TXOP (i.e., access of other STAs is restricted) can be ensured within the r-TWT SP by using NAVs or silent intervals such as (MU)RTS / CTS or CTS to itself. Before a specific r-TWT SP starts, if there is a TXOP of another STA (i.e., a non-member STA) other than the STA with membership for a specific r-TWT scheduling, the specific r-TWT SP must be stopped. And, the TXOP of another STA (i.e., a non-member STA) can be additionally performed after the specific r-TWT SP ends.

[0162] Silent interval

[0163] The silence interval may be indicated by a silence element or a silence channel element. Basically, a STA receiving the silence element or the silence channel element may not perform transmission (or channel access) in the corresponding channel during the indicated silence interval.

[0164] Fig.11 is a diagram illustrating an exemplary format of a silence element and an exemplary format of a silent channel element to which the present disclosure can be applied.

[0165] Fig.11 (a) shows an exemplary format of a silence element.

[0166] The silence element may define an interval during which no transmission is performed in the current channel. The corresponding interval may also be used to assist in performing channel measurements (or channel tests) without interference from other STAs in the BSS.

[0167] The Element ID field may have a value corresponding to a silent element (eg, 40). The Length field may have a value corresponding to the length of the subsequent field (eg, 6 octets).

[0168] The silence count field may have a value corresponding to the number of TBTTs just before (until) the beacon interval at which the next silence interval starts. Among the values ​​of the corresponding fields, 0 may be reserved.

[0169] The Silent Period field may have a value corresponding to the number of beacon intervals between the starting points of the regularly scheduled silent intervals defined by the corresponding silent element. If the value of the Silent Period field is 0, it may indicate that no periodic silent interval is defined.

[0170] The silence duration field may have a value indicating the duration of the silence interval in time units (TUs). For example, 1 TU may correspond to 1024 microseconds (μs).

[0171] The Silence Offset field may have a value representing an offset from the TBTT specified by the Silence Count field to the starting point of the silence interval in units of TU. The value of the Silence Offset field may be a value less than one beacon interval.

[0172] The silence element may be included in a beacon frame, a probe response frame, etc. For example, the AP may schedule a silence interval by sending a beacon / probe response frame including a silence element. Multiple independent silence intervals may be scheduled. The STA may set a NAV (on a silence channel) for a length corresponding to the silence interval.

[0173] Fig.11 (b) shows an exemplary format of a silent channel element.

[0174] The Silent Channel element indicates that a secondary channel (e.g., a secondary 80 MHz channel of a VHT BSS) will be silent during a silent interval, and may also be used to indicate whether a primary channel (e.g., a primary 80 MHz channel of a VHT BSS) may be used during a silent interval in an infrastructure BSS. A silent interval may be established by using a Silent Channel element, or in an infrastructure BSS, a silent interval may be established by using a Silent Channel element when the value of the AP Silent Mode field is 1.

[0175] The silent channel element may be included in a beacon frame, a probe response frame, or the like.

[0176] The AP Silent Mode field may specify STA operation in the infrastructure BSS during the silent interval. If communication to the AP in the primary 80 MHz channel (during the silent interval) is allowed, the AP Silent Mode field may have a value of 1. Otherwise, the AP Silent Mode field may have a value of 0.

[0177] When the value of the AP Silent Mode field is 1, the Silent Channel element may include a Silent Count field, a Silent Period field, a Silent Duration field, and a Silent Offset field. Otherwise, the corresponding fields may not be included in the Silent Channel element.

[0178] The silence count field, silence period field, silence duration field, and silence offset field in the silent channel element are the same as the corresponding fields in the silent element field, so repeated description is omitted.

[0179] Next, a silent interval may be scheduled for the r-TWT SP. For example, an AP supporting r-TWT (e.g., an EHT AP or an AP supporting a subsequent EHT (e.g., UHR) standard) may schedule a silent interval that overlaps with the r-TWT SP. It may be referred to as an overlapping silent interval. If scheduled, the overlapping silent interval may be required to have a duration of 1TU and to start at the same time point as the starting point of the corresponding r-TWT SP.

[0180] The overlapping silence interval may be configured by including at least one silence element in a beacon frame, a probe response frame, etc. transmitted by an AP supporting r-TWT (eg, an EHT AP).

[0181] Non-AP EHT STAs may behave as if there are no overlapping silent intervals.

[0182] Alternatively, the AP may use the silent interval for channel measurement / testing by managing or avoiding overlap between the scheduled silent interval and the r-TWT SP.

[0183] Silent channel based operation for extended bandwidth

[0184] The above-mentioned silent channel element is defined based on a WLAN system (e.g., VHT technology) with a 160MHz bandwidth, and specifically, the values ​​0 and 1 of the AP silent mode field in the silent channel element are defined to indicate whether communication to the AP is allowed only for the main 80MHz channel during the silent interval. In a WLAN system that supports an extended bandwidth exceeding 160MHz bandwidth (e.g., 240MHz, 320MHz, 480MHz, 640MHz, etc.), it is necessary to indicate whether communication is allowed during the silent interval on various combinations of channels, and a new method is needed to support this. The present disclosure includes a method for newly defining the AP silent mode field of the silent channel element to indicate one of various combinations of channels within the extended bandwidth that allow and / or do not allow communication to the AP.

[0185] Fig.12 is a diagram for explaining an example of an operation of an STA based on a silent channel according to the present disclosure.

[0186] In S1210, the STA may receive information from the AP indicating one of a plurality of combinations of channels within a bandwidth that allow or do not allow communication to the AP. The corresponding information may be included, for example, in an AP silent mode field within a silent channel element. Whether communication to the AP is allowed may be based on a predetermined time interval (e.g., a silent interval).

[0187] The plurality of combinations may include a combination of channels that allow communication to the AP. The plurality of combinations may include a combination of channels that do not allow communication to the AP. The plurality of combinations may include a combination of channels that allow communication to the AP and a combination of channels that do not allow communication to the AP. One of the plurality of combinations may correspond to a combination indicating that communication to the AP is not allowed in all channels within the bandwidth (i.e., the entire bandwidth).

[0188] The combination of allowed channels or the combination of disallowed channels may include continuous channels in the frequency domain, or may include non-contiguous channels.

[0189] In the bandwidth, the main channel can be defined with various channel widths. For example, in the 320MHz bandwidth, the main 160MHz channel (P160), the main 80MHz channel (P80), the main 40MHz channel (P40) and the main 20MHz channel (P20) can be defined. In the 240MHz bandwidth, the P160, P80, P40 and P20 channels can be defined. In the 640MHz bandwidth, the P320, P160, P80, P40 and P20 channels can be defined. In the 480MHz bandwidth, the P320, P160, P80, P40 and P20 channels can be defined. In the bandwidth, the main channel with a wider channel width can be defined as including the main channel with a narrower channel width. The remaining channels except the main channel can correspond to the auxiliary channels, and the auxiliary channels can also be defined with various channel widths. Therefore, in a bandwidth, a combination of a main channel with various channel widths and at least one auxiliary channel with various channel widths can be defined.

[0190] The allowed channels may include only one allowed primary channel, or may include one allowed primary channel and one allowed secondary channel. For example, for a 320MHz bandwidth, a first combination may correspond to P160, a second combination may correspond to P160 and a first secondary 80MHz channel (S80), and a third combination may correspond to P160 and a second secondary 80MHz channel (S80-1). For example, for a 320MHz bandwidth, a first combination may correspond to P80, a second combination may correspond to P80 and S80, a third combination may correspond to P80 and S80-1, and a fourth combination may correspond to P80 and a third secondary 80MHz channel (S80-2).

[0191] Additionally or alternatively, the allowed channels may include one allowed primary channel and multiple allowed secondary channels. For example, for a 320 MHz bandwidth, a first combination may correspond to P80, S80, and S80-1, a second combination may correspond to P80, S80-1, and S80-2, and a third combination may correspond to P80, S80, and S80-2.

[0192] Additionally or alternatively, a combination of channels that are allowed to be configured with only auxiliary channels but no primary channels may be defined. Although generally defined to operate on channels including the primary channel, operations related to subchannel selective transmission, etc. may support operation only in the auxiliary channel during some time intervals, and the corresponding channel may also be indicated by a silent channel.

[0193] Next, the disallowed channels may include one disallowed secondary channel. For example, within a 320 MHz bandwidth, the first combination may correspond to S80, the second combination may correspond to S80-1, and the third combination may correspond to S80-2.

[0194] Additionally or alternatively, the disallowed channels may include multiple disallowed secondary channels. For example, within a 320 MHz bandwidth, the first combination may correspond to S80 and S80-1, the second combination may correspond to S80-1 and S80-2, and the third combination may correspond to S80 and S80-2.

[0195] Additionally or alternatively, the disallowed channels may include only one disallowed primary channel, or may include one disallowed primary channel and at least one disallowed secondary channel. For example, within a 320 MHz bandwidth, a first combination may correspond to P80, a second combination may correspond to P80 and S80, a third combination may correspond to P80 and S80-1, and a fourth combination may correspond to P80 and S80-2.

[0196] Additionally or alternatively, the disallowed channels may include one disallowed primary channel and multiple disallowed secondary channels. For example, for a 320 MHz bandwidth, a first combination may correspond to P80, S80, and S80-1, a second combination may correspond to P80, S80-1, and S80-2, and a third combination may correspond to P80, S80, and S80-2.

[0197] These allowed and / or disallowed channels may be related to multi-AP operations between an AP and another AP. For example, by exchanging information about channels, usage time, etc. for multi-AP operations between APs, resources allocated to each AP may be determined. For example, when different frequency resources (e.g., channels) are allocated to multiple APs during the same time interval, as described above, the channel to which the corresponding AP is allocated may be directly / indirectly indicated to the STA as an allowed channel, and the channel to which another AP is allocated may be directly / indirectly indicated to the STA as an unallowed channel.

[0198] In S1220, the STA may perform communication to the AP on at least one channel based on the one combination indicated in S1210. The communication to the AP may be performed during a predetermined time interval (eg, a silent interval).

[0199] As described above, one combination indicated to the STA may directly indicate a channel where communication to the AP is allowed, or may indirectly indicate that communication to the AP is allowed among the remaining channels by directly indicating a channel where communication to the AP is not allowed.

[0200] The channel on which the STA actually performs or attempts communication with the AP (or performs channel access) may be all or part of the channels on which communication with the AP is allowed determined directly / indirectly based on the indicated one combination.

[0201] Fig.12 The method described in the example can be Figure 1 The first device (100) performs. For example, Figure 1 At least one processor (102) of the first device (100) may be configured to receive information indicating a combination of channels for which communication to the second device (200) is allowed / not allowed through at least one transceiver (106), and based on this, perform communication to the second device (200) in all or part of the allowed channels or channel access for this purpose. In addition, at least one memory (104) of the first device (100) may store instructions for executing when executed by the at least one processor (102). Fig.12 Examples or instructions of the methods described in the examples described below.

[0202] Fig.13 is a diagram for explaining an example of an operation of an AP based on a silent channel according to the present disclosure.

[0203] In S1310, the AP may send information indicating one of a plurality of combinations of channels within a bandwidth that allow or do not allow communication from the STA to the STA. The corresponding information may be included in, for example, an AP silent mode field within a silent channel element. Whether communication from the STA to the AP is allowed may be based on a predetermined time interval (e.g., a silent interval).

[0204] In S1320, the AP may perform communication with the STA on at least one channel based on the one combination indicated in S1310. The communication with the STA may be performed during a predetermined time interval (eg, a silent interval).

[0205] exist Fig.13 In the example of the combination of the allowed channel / the disallowed channel and the channel for performing communication determined based on the corresponding combination are the same as Fig.12 are the same as those in the examples, so repeated description is omitted.

[0206] Fig.13 The method described in the example can be Figure 1 The second device (200) is executed. For example, Figure 1At least one processor (202) of the second device (200) may be configured to send information indicating a combination of channels for which communication is permitted / not permitted to the first device (100) through at least one transceiver (206), and based on this, perform communication with the first device (100) in all or part of the permitted channels. In addition, at least one memory (204) of the second device (200) may store instructions for executing when executed by the at least one processor (202). Fig.13 Examples or instructions of the methods described in the examples described below.

[0207] Fig.12 and Fig.13 Examples of may correspond to some of the various examples of the present disclosure. In the following, the present disclosure is described in more detail including Fig.12 and Fig.13 Various examples of examples.

[0208] In the embodiments described below, the extended bandwidth is described by using a 320 MHz bandwidth and a 240 MHz bandwidth as representative examples to which the present disclosure is applied, but examples of the present disclosure may be equally applied to other extended bandwidths such as 480 MHz, 640 MHz, and the like.

[0209] In addition, the scope of the present disclosure is not limited by the names of silent channel elements, AP silent mode fields, etc., but elements and fields of any names corresponding to the information included in elements and fields of such exemplary names are also included in the scope of the present disclosure.

[0210] Implementation Method 1

[0211] This embodiment includes an example based on indication information about a channel that allows / does not allow frame exchange between an AP and a STA in a 320 MHz bandwidth.

[0212] For example, a specific value of the AP Silent Mode field in the Silent Channel element may indicate that data transmission or reception (or frame exchange) between the AP and the STA is allowed during the silent interval in a specific channel on a specific bandwidth. Since the AP Silent Mode field of the Silent Channel element has a length of 8 bits (1 octet), it can indicate 256 values ​​from 0 to 255. An example for indicating a combination of allowed / disallowed channels by using values ​​other than the two values ​​0 and 1 previously defined in the AP Silent Mode field is described below. The scope of the present disclosure is not limited to the exemplary correspondence between a specific value of the AP Silent Mode field and a combination of a specific channel indicated thereby, and may include various correspondences other than the exemplary correspondence.

[0213] Figures 14 to 16is a diagram for explaining various examples of operations based on silent channels according to the present disclosure.

[0214] exist Fig.14 In the example of (a), when the value of the AP silent mode field is 2, the STA may be defined as transmitting or receiving data with the AP in P160 during the silent interval. It may indirectly indicate that data transmission or reception is not allowed in the remaining S160 except P160.

[0215] The STA may receive a frame (e.g., a beacon frame) in which 2 is included as the value of the AP Silent Mode field within the Silent Channel element from the AP. Thereafter, since data transmission or reception is allowed only in P160 during the silent interval announced from the AP through the Silent Element, the corresponding STA may perform data transmission or reception within P160.

[0216] exist Fig.14 In the example of (b), when the value of the AP silent mode field is 0, it can be defined that all channels within the bandwidth (ie, P80, P160, and auxiliary channels) are silent during the silent interval (ie, communication is not allowed in all channels within the bandwidth).

[0217] The STA may receive a frame in which 0 is included as a value of the AP silent mode field within the silent channel element from the AP. Thereafter, during the silent interval announced from the AP through the silent element, the corresponding STA does not perform data transmission or reception in the entire bandwidth.

[0218] exist Fig.15 In the example of (a), for a STA (e.g., EHTSTA) supporting operation in a bandwidth of 320 MHz or higher, when the bandwidth configured by the AP for the corresponding STA is 320 MHz and the value of the AP silent mode field is 1, the corresponding STA is allowed to send or receive data with the AP only in P80 during the silent interval. It can indirectly indicate that data transmission or reception is not allowed in S80, S80-1, and S80-2 other than P80.

[0219] The STA may receive a frame in which 1 is included as the value of the AP Silent Mode field in the Silent Channel element from the AP. Thereafter, since data transmission or reception is allowed only in P80 during the silent interval announced from the AP through the Silent Element, the corresponding STA may perform data transmission or reception in P80.

[0220] Fig.15 The example of (a) corresponds to a case where communication is allowed during the silent interval only for one primary channel, and Fig.15 (b) Fig.16 (a) and Fig.16The example of (b) corresponds to a case where communication is allowed during a silent interval on one primary channel and one secondary channel.

[0221] For example, when a STA performs communication on multiple channels, it can send data (e.g., PPDU) on the multiple channels simultaneously. Fig.15 (b) Fig.16 (a) and Fig.16 In the example of (b), the starting point and the end point of the data sent on a primary channel and a secondary channel may be the same. For example, in the exemplary drawings of the present disclosure, data sent / received at the same starting point and the same end point on multiple channels may represent sending / receiving one data (e.g., PPDU) on multiple channels.

[0222] exist Fig.15 In the example of (b), the AP indicates to the STA that the value of the AP silent mode field of the silent channel element is 3, so the STA can perform data transmission or reception on P80 and S80 during the silent interval. Fig.16 In (a), the AP indicates to the STA that the value of the AP Silent Mode field of the Silent Channel Element is 4, so the STA can perform data transmission or reception on P80 and S80-1 during the silent interval. Fig.16 In (b), the AP indicates to the STA that the value of the AP Silent Mode field of the Silent Channel Element is 5, so the STA can perform data transmission or reception on P80 and S80-2 during the silent interval.

[0223] Fig.17 and Fig.18 is a diagram for explaining an additional example of an operation based on a silent channel according to the present disclosure.

[0224] Fig.17 (a) Fig.17 (b) and Fig.18 The example of (a) relates to a method for instructing a STA to be silent (i.e., not allow data transmission or reception) during a silent interval only in one of the secondary channels allocated to the STA. In other words, it is possible to indirectly indicate that data transmission or reception is allowed in the remaining channels except for the silent (i.e., not allowed) channel.

[0225] Fig.17 The example of (a) shows a case where the STA receives a frame in which the AP silent mode field is configured as 6. In the corresponding case, the STA can be silent only on S80 among its secondary channels during the silent interval, and can perform data transmission or reception with the AP in the remaining primary and secondary channels (ie, P80, S80-1, S80-2).

[0226] Fig.17 The example of (b) shows a case where the STA receives a frame in which the AP silent mode field is configured as 7. In the corresponding case, the STA can be silent only on S80-1 among its secondary channels during the silent interval, and can perform data transmission or reception with the AP in the remaining primary and secondary channels (ie, P80, S80, S80-2).

[0227] Fig.18 The example of (a) shows a case where the STA receives a frame in which the AP silent mode field is configured to be 8. In the corresponding case, the STA can be silent only on S80-1 among its secondary channels during the silent interval, and can perform data transmission or reception with the AP in the remaining primary and secondary channels (ie, P80, S80, S80-2).

[0228] In the above-described example, a combination of allowed channels / disallowed channels according to a value of the AP silent mode field may be shown in the following table.

[0229] [Table 1]

[0230]

[0231]

[0232] Fig.18 (b) shows an example in which the silent channel-based operation according to the present disclosure is applied to scheduling coordination between APs in a multi-AP environment. However, the silent channel-based operation according to the present disclosure is not only applied to multi-AP operation, but can also be applied to other operations / purposes.

[0233] Fig.18 The example of (b) assumes a case where AP1 and AP2 perform multi-AP operation. For example, AP1 and AP2 may correspond to slave APs under one master AP, or one of AP1 or AP2 may be a master AP and the other may be a slave AP. For example, a silent channel element according to the present disclosure may be used so that AP2 allocates an R-TWT SP for a predetermined time interval to a STA associated with AP2.

[0234] AP2 may send a request frame including information about the total time length / interval required for data transmission or reception to AP1. When AP1 may accept the corresponding request, it may send a response frame to AP2, which includes success status information indicating success, information about the start time of data transmission or reception allowed for AP2 (which may correspond to the start time of the silent interval that AP1 intends to allocate to the STA associated with it), or information such as the channel position used, channel width, etc. If AP1 may not accept AP2's request, it may send a response frame including status code information for rejecting the corresponding request to AP2.

[0235] When AP1 accepts the request of AP2, AP1 may configure the value of the AP silent mode within the silent channel element to 2, and transmit it to STA1 associated with AP1 through a beacon frame, etc. Therefore, it is not possible to indicate to STA1 that data transmission or reception of STA1 in the primary 160 MHz channel is allowed and data transmission or reception of STA1 in the secondary 160 MHz channel is not allowed for STA1 during the silent interval for STA1 associated with AP1.

[0236] Accordingly, during the silent interval, communication from STA2 associated with AP2 to AP2 may be allowed in the secondary 160 MHz channel. At this point, AP2 may provide STA2 with a silent channel element including an AP silent mode field through a beacon frame (not shown), the AP silent mode field being configured to indicate a value (e.g., a value other than 0 to 8 described above) indicating that communication is not allowed in P160 or communication is allowed only in S160.

[0237] Fig.18 The example of (b) corresponds to Fig.14 The example of (a) is applied to an example of multi-AP operation. Similarly, Fig.14 (b) to Fig.18 An example of (a) and Fig.19 The example and the following example described later are used to indicate a channel for allowing / not allowing communication to a STA associated with each of the corresponding APs when the APs operate on different frequency resources in the same time interval in a multi-AP operation. In other words, when the APs are directed to Fig.18 When the negotiation of multi-AP operation (i.e., resource allocation) between AP1 and AP2 in (b) is successful, the AP silent mode value in the silent channel element can be announced to each STA by configuring the AP silent mode value in the silent channel element to indicate that communication is allowed in the channel corresponding to the frequency resources allocated to it (or communication is not allowed in the channel corresponding to the frequency resources not allocated to it).

[0238] Thus, during a predetermined time interval, each AP may be scheduled to use an allocated channel and may allow data transmission or reception of the STA during a silent interval in a specific channel within the bandwidth.

[0239] Implementation Method 2

[0240] This embodiment includes an example based on indication information about a channel that allows / does not allow frame exchange between an AP and a STA in a 240 MHz bandwidth.

[0241] Fig.19 and Fig. 20 is a diagram for explaining an additional example of an operation based on a silent channel according to the present disclosure.

[0242] Fig.19 The example of (a) shows a case where the value of the AP Silent Mode field in the Silent Channel element provided from the AP through a beacon frame or the like is configured to be 0 to indicate that communication is not allowed in all channels within the bandwidth including P80. Therefore, when the STA receives an announcement through the Silent element, a case is shown where communication from the STA to the AP is not allowed (i.e., data transmission or reception is not performed) in all of P80, S80, and S80-1 during the silent interval.

[0243] Fig.19 The example of (b) shows a case where the value of the AP Silent Mode field in the Silent Channel element provided from the AP through a beacon frame or the like is configured to be 1 to indicate that communication is allowed within P80. This may correspond to a case where communication is indirectly indicated not to be allowed in S80 and S80-1 other than P80. Therefore, a case is shown where, when the STA receives an announcement through the Silent Element, communication from the STA to the AP may be performed within P80 during the silent interval and communication from the STA to the AP is not allowed in S80 and S80-1.

[0244] Fig. 20 The example of (a) shows a case where the value of the AP silent mode field in the silent channel element provided from the AP through a beacon frame or the like is configured to be 2 to indicate that communication is allowed in P80 and S80. This may correspond to a case where communication is indirectly indicated not to be allowed in S80-1 in addition to P80 and S80. Therefore, a case is shown where, when the STA receives an announcement through the silent element, communication from the STA to the AP may be performed in P80 and S80 during the silent interval and communication from the STA to the AP is not allowed in S80-1.

[0245] Fig. 20The example of (b) shows a case where the value of the AP Silent Mode field in the Silent Channel element provided from the AP through a beacon frame or the like is configured to be 3 to indicate that communication is allowed in P80 and S80-1. It may correspond to a case where communication is not allowed in S80 other than P80 and S80-1, which is indirectly indicated. Therefore, it is shown that when the STA receives an announcement through the Silent Element, communication from the STA to the AP can be performed in P80 and S80-1 during the silent interval and communication from the STA to the AP is not allowed in S80.

[0246] In the above-described example, a combination of allowed channels / disallowed channels according to a value of the AP silent mode field may be shown in the following table.

[0247] [Table 2]

[0248]

[0249] Regarding the examples in Table 1 and Table 2, a value of 0 for the AP Silent Mode field is conventionally defined as a case where communication to the AP is allowed only in the primary 80 MHz channel (corresponding to a value of 1). When defined in this manner, in a system where the bandwidth exceeds 160 MHz or operation is allowed only in a secondary channel other than the primary channel, it may be clear that communication is not allowed in the primary 80 MHz channel, but there is a problem in that it is unclear whether communication is allowed in the remaining channels. Therefore, as described above, the present disclosure includes an example in which a value of 0 for the AP Silent Mode field is novel and clearly indicates that communication is not allowed in all channels within the bandwidth.

[0250] When the AP silent mode field in the existing WLAN system can only indicate whether communication to the AP in the main 80 MHz channel within the 160 MHz bandwidth is allowed, in the present disclosure, the value of the AP silent mode field can indicate one of various combinations of allowed channels or various combinations of disallowed channels in the extended bandwidth (e.g., 240 MHz, 320 MHz, 480 MHz, 640 MHz, etc.). Therefore, it is possible to clearly indicate allowed channels / disallowed channels within the bandwidth in various environments, and provide a new method for flexibly and efficiently allocating frequency resources.

[0251] The above-mentioned embodiments are to combine the elements and features of the present disclosure in a predetermined form. Unless otherwise explicitly mentioned, each element or feature should be considered as optional. Each element or feature can be implemented in a form that is not combined with other elements or features. In addition, the embodiments of the present disclosure may include combined partial elements and / or features. The order of the operations described in the embodiments of the present disclosure may be changed. Some elements or features of an embodiment may be included in other embodiments, or may be replaced by corresponding elements or features of other embodiments. Obviously, the embodiments may include claims that do not have a clear reference relationship in the combined claims, or may be included as new claims by modification after application.

[0252] It is clear to those skilled in the relevant art that the present disclosure can be implemented in other specific forms within the scope of the essential features of the present disclosure. Therefore, the above detailed description should not be interpreted restrictively in every aspect, but should be considered as illustrative. The scope of the present disclosure should be determined by the reasonable interpretation of the attached claims, and all changes within the equivalent scope of the present disclosure are included in the scope of the present disclosure.

[0253] The scope of the present disclosure includes software or machine executable commands (e.g., operating systems, applications, firmware, programs, etc.) that perform operations in a device or computer according to the methods of various embodiments, and non-transitory computer-readable media that enable software or commands, etc. to be stored and executable in a device or computer. Commands that can be used to program a processing system that performs the features described in the present disclosure can be stored in a storage medium or a computer-readable storage medium, and the features described in the present disclosure can be implemented by using a computer program product that includes such a storage medium. The storage medium may include a high-speed random access memory, such as DRAM, SRAM, DDRRAM, or other random access solid-state storage devices, but is not limited thereto, and it may include non-volatile memory, such as one or more magnetic disk storage devices, optical disk storage devices, flash memory devices, or other non-volatile solid-state storage devices. The memory optionally includes one or more storage devices located away from the processor. The memory, or alternatively, the non-volatile memory device in the memory includes a non-transitory computer-readable storage medium. The features described in this disclosure may be stored in any machine-readable medium to control the hardware of a processing system, and may be integrated into software and / or firmware that allows the processing system to interact with other mechanisms using the results from the 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.

[0254] Industrial Applicability

[0255] The method proposed in the present disclosure is mainly described based on an example applied to a system based on IEEE 802.11 (5G system), but can be applied to various WLAN or wireless communication systems other than the system based on IEEE 802.11.

Claims

1. A method performed by a station STA in a wireless local area network WLAN system, the method comprising the following steps: receiving a silent channel element, the silent channel element including information indicating one of a plurality of combinations of channels within a bandwidth that allow communication to a first access point AP or channels that do not allow the communication to the first AP; as well as The communication to the first AP is performed on at least one channel based on the one combination.

2. The method according to claim 1, wherein: The plurality of combinations includes combinations of one allowed primary channel and zero or more allowed secondary channels.

3. The method according to claim 2, wherein: The one allowed primary channel in combination with the zero or more allowed secondary channels comprises the at least one channel over which the communication to the first AP is performed.

4. The method according to claim 2, wherein: The bandwidth is 320 MHz, the width of the primary channel is 160 MHz, and the width of the secondary channel is 160 MHz or 80 MHz.

5. The method according to claim 2, wherein: The bandwidth is 320 MHz or 240 MHz, the width of the primary channel is 80 MHz, and the width of the secondary channel is 80 MHz.

6. The method according to claim 2, wherein: At least one remaining secondary channel within the bandwidth other than the allowed primary channel and the zero or more allowed secondary channels corresponds to at least one secondary channel for which the communication to the first AP is not allowed.

7. The method according to claim 1, wherein: The plurality of combinations include a combination of at least one secondary channel among a plurality of secondary channels that does not allow the communication to the first AP.

8. The method according to claim 7, wherein: At least one remaining channel within the bandwidth other than at least one disallowed secondary channel comprises the at least one channel through which the communication to the first AP is performed.

9. The method according to claim 1, wherein: Based on the one combination indicated by the information, at least one secondary channel for which the communication to the first AP is not allowed includes at least one channel used by a second AP of a multi-AP operation.

10. The method according to claim 9, wherein: The multi-AP operation includes exchanging requests and responses for information including a used channel and a used time between the first AP and the second AP.

11. The method according to claim 1, wherein: The multiple combinations respectively correspond to different values ​​of the AP silent mode field of the silent channel element.

12. The method according to claim 1, wherein: The plurality of combinations include a combination indicating that the communication to the first AP is not allowed in all channels within the bandwidth.

13. The method according to claim 1, wherein: The silent channel element is included in a beacon frame or a probe response frame.

14. A station STA in a wireless local area network WLAN system, the STA comprising: at least one transceiver; as well as at least one processor connected to the at least one transceiver, Wherein, the at least one processor is configured to: receiving, by the at least one transceiver, a silent channel element, the silent channel element comprising information indicating one of a plurality of combinations of channels within a bandwidth that allow communication to a first access point AP or channels that do not allow the communication to the first AP; and The communication to the first AP is performed on at least one channel based on the one combination.

15. A method performed by a first access point (AP) in a wireless local area network (WLAN) system, the method comprising the following steps: Sending a silent channel element to a station STA, the silent channel element including information indicating one of a plurality of combinations of channels within a bandwidth that allow communication to the first AP or channels that do not allow the communication to the first AP; as well as Communication with the STA is performed on at least one channel based on the one combination.

16. A first access point (AP) in a wireless local area network (WLAN) system, the AP comprising: at least one transceiver; as well as at least one processor connected to the at least one transceiver, Wherein, the at least one processor is configured to: Sending, by the at least one transceiver, a silent channel element to a station STA, the silent channel element including information indicating one of a plurality of combinations of channels within a bandwidth that allow communication to the first AP or channels that do not allow the communication to the first AP; and Communication with the STA is performed on at least one channel based on the one combination through the at least one transceiver.

17. A processing unit configured to control a station (STA) in a wireless local area network (WLAN) system, the processing unit comprising: at least one processor; as well as At least one computer memory operatively connected to the at least one processor, the at least one computer memory storing instructions for performing the method according to any one of claims 1 to 13 based on execution by the at least one processor.

18. At least one non-transitory computer-readable medium storing at least one instruction, wherein: The at least one instruction is executed by at least one processor to control a station STA device to perform the method according to any one of claims 1 to 13 in a wireless local area network WLAN system.

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