Method and apparatus for signaling based on multi-access point operation in wireless LAN system

Abstract

Disclosed are an operation method and apparatus in a wireless LAN system. According to an embodiment disclosed herein, a method performed by a first STA in a wireless LAN system comprises the steps of: receiving a first downlink (DL) frame from a first access point (AP); and transmitting a first uplink (UL) frame for the first DL frame within or after a specific duration, where the specific duration may include a duration for transmitting a second DL frame from a second AP to a second STA, the first AP may be an overlapping basic service set (OBSS) AP, and the second AP may be a BSS AP.

Description

Technical Field

[0001] The present disclosure relates to communication operations in a wireless local area network (WLAN) system, and more particularly, to a signaling method and apparatus based on multi-access point operations in the WLAN system. 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 signaling method and device based on multi-access point operation in a wireless LAN system.

[0006] A technical problem of the present disclosure is to provide a method and apparatus for transmitting data using a coordinated spatial multiplexing (C-SR) technique in a wireless LAN system.

[0007] A technical problem of the present disclosure is to provide a method and apparatus for transmitting UL ACK according to DL PPDU transmission of OBSSAP when a multi-access point operation is performed in a wireless LAN system.

[0008] 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.

[0009] Technical Solution

[0010] According to one aspect of the present disclosure, a method for performing communication by a first station (STA) in a wireless LAN system may include: receiving a first downlink (DL) frame from a first access point (AP); and sending a first uplink (UL) frame for the first DL frame to the first AP within or after a specific duration, and the specific duration may include a duration for sending a second DL frame from a second AP to a second STA, and the first AP may be an OBSS (Overlapping Basic Service Set) AP, and the second AP may be a BSS AP.

[0011] According to additional aspects of the present disclosure, a method performed by a first access point (AP) in a wireless LAN system may include: sending a first downlink (DL) frame to a first station (STA); and receiving a first uplink (UL) frame for the first DL frame from the first STA within or after a specific duration, and the specific duration may include a duration for sending a second DL frame from a second AP to a second STA, and the first AP may be an OBSS (Overlapping Basic Service Set) AP, and the second AP may be a BSS AP.

[0012] Technical Effects

[0013] According to various embodiments of the present disclosure, a method and apparatus for signaling based on multiple access point operations in a wireless LAN system may be provided.

[0014] According to various embodiments of the present disclosure, a method and apparatus for transmitting data using the C-SR technology in a wireless LAN system may be provided.

[0015] According to various embodiments of the present disclosure, a method and apparatus for transmitting UL ACK according to DL PPDU transmission of an OBSS AP when a multi-access point operation is performed in a wireless LAN system may be provided.

[0016] 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

[0017] 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.

[0018] Figure 1 A configuration block diagram of a wireless communication device according to an embodiment of the present disclosure is illustrated.

[0019] Figure 2 is a diagram illustrating an exemplary structure of a WLAN system to which the present disclosure can be applied.

[0020] Figure 3 It is a diagram for explaining a link establishment process to which the present disclosure can be applied.

[0021] Figure 4 This is a diagram for explaining a backoff process to which the present disclosure can be applied.

[0022] Figure 5 It is a diagram for explaining a frame transmission operation based on CSMA / CA to which the present disclosure can be applied.

[0023] 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.

[0024] 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.

[0025] Figures 8 to 10 is a diagram for explaining an example of a resource unit of a wireless LAN system to which the present disclosure can be applied.

[0026] Fig.11 is a diagram for explaining an example of a DRU to which the present disclosure can be applied.

[0027] Fig.12 is a diagram showing an exemplary format of a trigger frame to which the present disclosure may be applied.

[0028] Fig.13 An example of a PPDU format to which the present disclosure can be applied is illustrated.

[0029] Fig.14 is a diagram showing an exemplary format of a trigger frame to which the present disclosure may be applied.

[0030] Fig.15 It is a diagram for explaining various transmission and reception techniques in a MAP environment to which the present disclosure can be applied.

[0031] Fig.16 is a diagram for describing a process of obtaining channel state information between BSS / OBSS AP / STA according to an embodiment of the present disclosure.

[0032] Fig.17 is a diagram for describing an operation performed by a first STA according to an embodiment of the present disclosure.

[0033] Fig.18 is a diagram for describing operations performed by a first AP according to an embodiment of the present disclosure.

[0034] Fig.19is a diagram for describing a process of transmitting UL ACK according to DL PPDU transmission of an OBSS AP according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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 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.

[0039] 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".

[0040] 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.

[0041] Hereinafter, technical features of examples to which the present disclosure can be applied will be described.

[0042] Figure 1 A block diagram of a wireless communication device according to an embodiment of the present disclosure is illustrated.

[0043] Figure 1 The 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.

[0044] Figure 1 The devices 100 and 200 illustrated in the example may be referred to as stations (STAs). Figure 1The 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.

[0045] 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.

[0046] 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.

[0047] 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.

[0048] 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.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] 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.

[0053] 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). 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.

[0054] Hereinafter, a 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 a 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.

[0055] Figure 2 is a diagram illustrating an exemplary structure of a wireless LAN system to which the present disclosure can be applied.

[0056] 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.

[0057] 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.

[0058] 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).

[0059] 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.

[0060] 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.

[0061] 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).

[0062] 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.

[0063] 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.

[0064] In addition to the above-mentioned structure of the DS, an extended service set (ESS) may also be configured to provide wide coverage.

[0065] 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.

[0066] 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.

[0067] Figure 3 is a diagram for explaining a link establishment process to which the present disclosure can be applied.

[0068] 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.

[0069] 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.

[0070] 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).

[0071] 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.

[0072] 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.

[0073] 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.

[0074] 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.

[0075] 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.

[0076] 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.

[0077] 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.

[0078] 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.

[0079] 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.

[0080] Figure 4 It is a diagram for explaining a backoff process to which the present disclosure can be applied.

[0081] 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.

[0082] 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).

[0083] Reference Figure 4 , the operation based on the random backoff period will be described. When the occupied / busy medium becomes idle, multiple STAs can attempt to send data (or frames). As a method to minimize conflicts, each of the STAs can 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 can be determined as one of the values ​​ranging from 0 to CW. Here, CW is the contention window parameter value. The CW parameter is assigned CWmin as an initial value, but can take a value twice as large as in the event of a transmission failure (for example, when an ACK for the transmitted frame is not received). When the CW parameter value reaches CWmax, data transmission can be attempted while maintaining the CWmax value until the data transmission is successful, and when the data transmission is successful, the CWmin value is reset. The values ​​of CW, CWmin and CWmax are preferably set to 2.n -1(n=0, 1, 2, . . . ).

[0084] 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.

[0085] exist Figure 4 In the example of , when the packet to be sent arrives at the MAC of STA 3, 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 the 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 occupation 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 4 The 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.

[0086] As in Figure 4In 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.

[0087] 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.

[0088] Figure 5 is a diagram for explaining a frame transmission operation based on CSMA / CA to which the present disclosure can be applied.

[0089] 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.

[0090] 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.

[0091] 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.

[0092] 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.

[0093] 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.

[0094] 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.

[0095] 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.

[0096] 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.

[0097] 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.

[0098] In this manner, information transmission / reception in the wireless LAN system is performed in the form of frames, and for this purpose, a PHY layer protocol data unit (PPDU) frame format is defined.

[0099] The basic PPDU frame may include a short training field (STF), a long training field (LTF), a signal (SIG) field, and a data field. The most basic (e.g., non-high throughput (HT)) PPDU frame format may consist of only L-STF (legacy STF), L-LTF (legacy-LTF), a SIG field, and a data field. In addition, depending on the type of PPDU frame format (e.g., HT mixed format PPDU, HT greenfield format PPDU, VHT (very high throughput) PPDU, etc.), additional (or different types of) STF, LTF, and SIG fields may be included between the SIG field and the data field (to be referred to later). Figure 7 Describe this).

[0100] 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.

[0101] The SIG field may include a rate field and a length field, etc. The rate field may include information about the modulation and coding rate of the data. The length field may include information about the length of the data. In addition, the SIG field may include a parity bit, a SIG tail bit, etc.

[0102] 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.

[0103] 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 frame format.

[0104] 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.

[0105] The Null Data Packet (NDP) frame format means a frame format that does not include a data packet. That is, the NDP frame refers to a frame format that includes a physical layer convergence procedure (PLCP) header portion (i.e., STF, LTF, and SIG fields) in a common PPDU frame format and does not include the remaining portion (i.e., data field). The NDP frame may also be referred to as a short frame format.

[0106] 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.

[0107] 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.

[0108] The HT PPDU format (IEEE 802.11n) additionally includes HT-SIG, HT-STF, and HT-LFT fields with respect to the basic PPDU format. Figure 7 The HT PPDU format shown in the figure 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).

[0109] An example of a VHT PPDU format (IEEE 802.11ac) additionally includes VHT SIG-A, VHT-STF, VHT-LTF, and VHT-SIG-B fields for the basic PPDU format.

[0110] Examples of HE PPDU formats (IEEE 802.11ax) additionally include repeated L-SIG (RL-SIG), HE-SIG-A, HE-SIG-B, HE-STF, HE-LTF, and packet extension (PE) fields with respect to the basic PPDU format. According to the detailed examples of the HE PPDU format, some fields may be excluded or their lengths may vary. For example, the HE-SIG-B field is included in the HE PPDU format for multi-user (MU), while the HE-SIG-B is not included in the HE PPDU format for single user (SU). In addition, the PPDU format based on HE trigger (TB) does not include the HE-SIG-B, and the length of the HE-STF field may vary to 8us. 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 16us.

[0111] Figures 8 to 10 is a diagram for explaining an example of a resource unit of a WLAN system to which the present disclosure can be applied.

[0112] Reference Figures 8 to 10 , a resource unit (RU) defined in a wireless LAN system will be described. A RU may include multiple subcarriers (or tones). When a signal is transmitted to multiple STAs based on an OFDMA scheme, an RU may be used. In addition, an RU may be defined even when a signal is transmitted to one STA. An RU may be used for a data field, an STF, an LTF, etc. of a PPDU.

[0113] like Figures 8 to 10 As shown in , RUs corresponding to different numbers of tones (i.e., subcarriers) are used to construct some fields of a 20 MHz, 40 MHz, or 80 MHz X-PPDU (X is HE, EHT, etc.). For example, resources may be allocated in RU units as shown for the X-STF, X-LTF, and data fields.

[0114] Figure 8 is a diagram illustrating exemplary allocation of resource units (RUs) used on a 20 MHz frequency band.

[0115] like Figure 8As shown at the top of , 26-units (i.e., units corresponding to 26 tones) may be allocated. 6 tones may be used as a guard band in the leftmost band of the 20 MHz band, and 5 tones may be used as a guard band in the rightmost band of the 20 MHz band. In addition, 7 DC tones are inserted into the center band (that is, the DC band), and 26-units corresponding to each of the 13 tones may exist on the left and right sides of the DC band. In addition, 26-units, 52-units, and 106-units may be allocated to other bands. Each unit may be allocated for STA or user.

[0116] Figure 8 The RU allocation is used not only for the multi-user (MU) case but also for the single-user (SU) case, and in this case, a 242-unit can be used, such as Figure 8 In this case, three DC tones can be inserted.

[0117] exist Figure 8 In the examples, various sizes of RUs are illustrated, that is, 26-RU, 52-RU, 106-RU, 242-RU, etc., but the specific sizes of these RUs can be reduced or expanded. Therefore, in the present disclosure, the specific size of each RU (i.e., the number of corresponding tones) is exemplary and not restrictive. In addition, within a predetermined bandwidth (e.g., 20 MHz, 40 MHz, 80 MHz, 160 MHz, 320 MHz, ...) in the present disclosure, the number of RUs can vary according to the size of the RU. In the following description, Fig. 9 and / or Fig.10 The fact that the size and / or number of RUs can vary is related to Figure 8 The same example.

[0118] Fig. 9 is a diagram illustrating exemplary allocation of resource units (RUs) used on a 40 MHz frequency band.

[0119] As in Figure 8 As in the example using various RU sizes, you can also Fig. 9 In the example of , 26-RU, 52-RU, 106-RU, 242-RU, 484-RU, etc. are used. In addition, 5 DC tones can be inserted at the center frequency, 12 tones can be used as a guard band in the leftmost band of the 40 MHz band, and 11 tones can be used as a guard band in the rightmost band of the 40 MHz band.

[0120] Additionally, as shown, when used for a single user, a 484-RU may be used.

[0121] Fig.10 is a diagram illustrating exemplary allocation of resource units (RUs) used on an 80 MHz frequency band.

[0122] As in Figure 8 and Fig. 9 As in the example using various RU sizes, you can also Fig.10 In the example of 26-RU, 52-RU, 106-RU, 242-RU, 484-RU, 996-RU, etc. are used. In addition, in the case of 80MHz PPDU, the RU allocation of HE PPDU and EHT PPDU can be different, and Fig.10 The example of FIG. 4 shows an example of RU allocation for an 80 MHz EHT PPDU. Fig.10 The scheme in which 12 tones in the example are used as a guard band in the leftmost band of the 80 MHz band and 11 tones are used as a guard band in the rightmost band of the 80 MHz band is the same as in the HE PPDU and the EHT PPDU. Unlike the HE PPDU in which 7 DC tones are inserted in the DC band and there is a 26-RU corresponding to each of the 13 tones on the left and right sides of the DC band, in the EHT PPDU, 23 DC tones are inserted in the DC band and there is a 26-RU on the left and right sides of the DC band. Unlike the HE PPDU in which one empty subcarrier exists between the 242-RUs instead of the center band, there are five empty subcarriers in the EHT PPDU. In the HE PPDU, one 484-RU does not include an empty subcarrier, but in the EHT PPDU, one 484-RU includes 5 empty subcarriers.

[0123] Additionally, as shown, when used for a single user, 996-RU may be used, and in this case, 5 DC tones are inserted as with HEPPDU and EHT PPDU.

[0124] exist Fig.10 In the example, the EHT PPDU on 160MHz can be configured with multiple 80MHz sub-blocks. The RU allocation for each 80MHz sub-block can be the same as Fig.10 If the 80 MHz sub-block of a 160 MHz or 320 MHz EHT PPDU is not punctured and the entire 80 MHz sub-block is used as a RU or part of a multiple RU (MRU), the 80 MHz sub-block can be used Fig.10 The 996-RU.

[0125] Here, the MRU corresponds to a group of subcarriers (or tones) consisting of multiple RUs, and the multiple RUs constituting the MRU may be RUs of the same size or RUs of different sizes. For example, a single 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. Here, the multiple RUs constituting one MRU may correspond to a small size (e.g., 26, 52, or 106) RU or a large size (e.g., 242, 484, or 996) RU. That is, one MRU including a small size RU and a large size RU may not be configured / defined. In addition, the multiple RUs constituting one MRU may be continuous in the frequency domain, or may not be continuous.

[0126] When an 80 MHz sub-block includes RUs less than 996-tones or a portion of the 80 MHz sub-block is punctured, the 80 MHz sub-block may use RU allocations other than the 996-tone RUs.

[0127] The RU of the present disclosure may be used for uplink (UL) and / or downlink (DL) communication. For example, when trigger-based UL-MU communication is performed, the STA (e.g., AP) that sends the trigger may allocate a first RU (e.g., 26 / 52 / 106 / 242-RU, etc.) to the first STA through trigger information (e.g., a trigger frame or a trigger response schedule (TRS)), and allocate a second RU (e.g., 26 / 52 / 106 / 242-RU, etc.) to the second STA. Thereafter, the first STA may send a first trigger-based (TB) PPDU based on the first RU, and the second STA may send a second TB PPDU based on the second RU. The first / second TB PPDU may be sent to the AP in the same time period.

[0128] For example, when a DL MU PPDU is configured, the STA (e.g., AP) that transmits the DL MU PPDU may allocate a first RU (e.g., 26 / 52 / 106 / 242-RU, etc.) to the first STA, and allocate a second RU (e.g., 26 / 52 / 106 / 242-RU, etc.) to the second STA. That is, the transmitting STA (e.g., AP) may transmit the HE-STF, HE-LTF, and data fields for the first STA through the first RU in one MU PPDU, and transmit the HE-STF, HE-LTF, and data fields for the second STA through the second RU.

[0129] Information about the allocation of RUs may be signaled in HE PPDU format through HE-SIG-B.

[0130] Fig.11 An example structure of the HE-SIG-B field is illustrated.

[0131] As shown, the HE-SIG-B field may include common fields and user-specific fields. If HE-SIG-B compression is applied (e.g., full bandwidth MU-MIMO transmission), the common fields may not be included in the HE-SIG-B, and the HE-SIG-B content channel may include only user-specific fields. If HE-SIG-B compression is not applied, the common fields may be included in the HE-SIG-B.

[0132] The common field may include information about RU allocation (eg, RU assignment, RUs allocated for MU-MIMO, the number of MU-MIMO users (STAs), etc.).

[0133] The common field may include N*8 RU allocation subfields. Here, N is the number of subfields, N=1 in the case of 20 or 40MHz MU PPDU, N=2 in the case of 80MHz MU PPDU, N=4 in the case of 160MHz or 80+80MHz MU PPDU, and so on. An 8-bit RU allocation subfield may indicate the size (26, 52, 106, etc.) and frequency position (or RU index) of the RU included in the 20MHz band.

[0134] For example, if the value of the 8-bit RU Allocation subfield is 00000000, this may indicate that Figure 8 In the example, nine 26-RUs are allocated in sequence from the leftmost side to the rightmost side, if the value is 00000001, this may indicate that seven 26-RUs and one 52-RU are allocated in sequence from the leftmost side to the rightmost side, and if the value is 00000010, this may indicate that five 26-RUs, one 52-RU, and two 26-RUs are allocated in sequence from the leftmost side to the rightmost side.

[0135] As an additional example, if the value of the 8-bit RU Allocation subfield is 01000y2y1y0, this may indicate that Figure 8 In the example, one 106-RU and five 26-RUs are allocated from the leftmost to the rightmost. In this case, in the MU-MIMO scheme, multiple users / STAs can be allocated to the 106-RU. Specifically, up to 8 users / STAs can be allocated to the 106-RU, and the number of users / STAs allocated to the 106-RU is determined based on the 3-bit information (i.e., y2y1y0). For example, when the 3-bit information (y2y1y0) corresponds to a decimal value N, the number of users / STAs allocated to the 106-RU can be N+1.

[0136] Basically, one user / STA can be assigned to each of multiple RUs, and different users / STAs can be assigned to different RUs. For RUs larger than a predetermined size (e.g., 106, 242, 484, 996-tones, ...), multiple users / STAs can be assigned to one RU, and the MU-MIMO scheme can be applied to multiple users / STAs.

[0137] The set of user-specific fields includes information about how all users (STAs) of the corresponding PPDU decode their payloads. The user-specific field may contain zero or more user block fields. The non-end-user block field includes two user fields (ie, information to be used for decoding in two STAs). The end-user block field contains one or two user fields. The number of user fields may be indicated by the RU allocation subfield of the HE-SIG-B, the number of symbols of the HE-SIG-B, or the MU-MIMO user field of the HE-SIG-A. The user-specific field may be encoded separately from the common field or independently of the common field.

[0138] Fig.12 is a diagram for explaining a MU-MIMO method in which multiple users / STAs are assigned to one RU.

[0139] exist Fig.12 In the example, assume that the value of the RU allocation subfield is 01000010. This corresponds to the case where y2y1y0=010 in 01000y2y1y0. 010 corresponds to 2 in decimal (i.e., N=2) and may indicate that 3 (=N+1) users are allocated to one RU. In this case, one 106-RU and five 26-RUs may be allocated sequentially from the leftmost to the rightmost of a specific 20 MHz band / channel. Three users / STAs may be allocated to the 106-RU in a MU-MIMO manner. As a result, a total of 8 users / STAs are allocated to the 20 MHz band / channel, and the user-specific field of the HE-SIG-B may include 8 user fields (i.e., 4 user block fields). Eight user fields may be assigned to an RU, such as Fig.12 shown.

[0140] The user field may be constructed based on two formats. The user field for MU-MIMO allocation may be constructed in a first format, and the user field for non-MU-MIMO allocation may be constructed in a second format. Fig.12 For example, user fields 1 to 3 may be based on a first format, and user fields 4 to 8 may be based on a second format. The first format and the second format may contain bit information of the same length (eg, 21 bits).

[0141] The user field of the first format (i.e., the format allocated for MU-MIMO) may be constructed as follows. For example, among all 21 bits of a user field, B0-B10 include identification information of the user (e.g., STA-ID, AID, partial AID, etc.), B11-B14 include spatial configuration information such as the number of spatial streams of the corresponding user, B15-B18 include modulation and coding scheme (MCS) information applied to the data field of the corresponding PPDU, B19 is defined as a reserved field, and B20 may include information about the coding type (e.g., binary convolutional coding (BCC) or low-density parity check (LDPC)) applied to the data field of the corresponding PPDU.

[0142] The user field of the second format (i.e., the format for non-MU-MIMO allocation) can be constructed as follows. For example, among all 21 bits of a user field, B0-B10 include identification information of the user (e.g., STA-ID, AID, partial AID, etc.), B11-B13 include information about the number of spatial streams (NSTS) applied to the corresponding RU, B14 includes information indicating whether beamforming is performed (or whether a beamforming control matrix is ​​applied), B15-B18 include modulation and coding scheme (MCS) information applied to the data field of the corresponding PPDU, B19 includes information indicating whether DCM (dual carrier modulation) is applied, and B20 may include information about the coding type (e.g., BCC or LDPC) applied to the data field of the corresponding PPDU.

[0143] The MCS, MCS information, MCS index, MCS field, etc. used in the present disclosure may be indicated by a specific index value. For example, the MCS information may be indicated as index 0 to index 11. The MCS information includes information about the constellation modulation type (e.g., BPSK, QPSK, 16-QAM, 64-QAM, 256-QAM, 1024-QAM, etc.) and the coding rate (e.g., 1 / 2, 2 / 3, 3 / 4, 5 / 6, etc.). Information about the channel coding type (e.g., BCC or LDPC) may be excluded from the MCS information.

[0144] Fig.13 An example of a PPDU format to which the present disclosure can be applied is illustrated.

[0145] Fig.13The PPDU of the present disclosure may be referred to as various names such as EHT PPDU, transmitted PPDU, received PPDU, first type or Nth type PPDU. For example, the PPDU or EHT PPDU of the present disclosure may be referred to as various names such as transmitted PPDU, received PPDU, first type or Nth type PPDU. In addition, the EHT PPU may be used in an EHT system and / or a new wireless LAN system in which the EHT system is improved.

[0146] Fig.13 The EHT MU PPDU corresponds to a PPDU carrying one or more data (or PSDU) for one or more users. That is, the EHT MU PPDU can be used for SU transmission and MU transmission. For example, the EHT MU PPDU can correspond to a PPDU for one receiving STA or multiple receiving STAs.

[0147] exist Fig.13 In the EHT TB PPDU, the EHT-SIG is omitted compared to the EHT MU PPDU. Upon receiving a trigger for ULMU transmission (eg, a trigger frame or TRS), the STA may perform UL transmission based on the EHT TB PPDU format.

[0148] exist Fig.13 In the example of the EHT PPDU format, L-STF to EHT-LTF correspond to a preamble or a physical preamble and can be generated / transmitted / received / acquired / decoded in a physical layer.

[0149] The subcarrier frequency spacing of the L-STF, L-LTF, L-SIG, RL-SIG, Universal Signal (U-SIG), EHT-SIG fields (these are called pre-EHT modulation fields) can be set to 312.5kHz. The subcarrier frequency spacing of the EHT-STF, EHT-LTF, data and PE fields (these are called EHT modulation fields) can be set to 78.125kHz. That is, the tone / subcarrier index of the L-STF, L-LTF, L-SIG, RL-SIG, U-SIG and EHT-SIG fields can be indicated in units of 312.5kHz, and the tone / subcarrier index of the EHT-STF, EHT-LTF, data and PE fields can be indicated in units of 78.125kHz.

[0150] Fig.13 The L-LTF and L-STF can be used with Figure 6 to Figure 7 The corresponding fields of the PPDU described in are constructed identically.

[0151] Fig.13The L-SIG field may consist of 24 bits and may be used to transmit rate and length information. For example, the L-SIG field includes 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. For example, the 12-bit length field may include information about the duration or length 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 HE PPDUs, the value of the length field may be determined as a multiple of 3 + 1 or a multiple of 3 + 2.

[0152] For example, the transmitting STA may apply BCC encoding based on the coding rate of 1 / 2 to 24 bits of information of the L-SIG field. Thereafter, the transmitting STA may obtain 48 BCC coded bits. BPSK modulation may be applied to the 48 coded bits to generate 48 BPSK symbols. The transmitting STA may map the 48 BPSK symbols to any position except the pilot subcarrier (e.g., {subcarrier index -21, -7, +7, +21}) and the DC subcarrier (e.g., {subcarrier index 0}). As a result, the 48 BPSK symbols may be mapped to subcarrier indexes -26 to -22, -20 to -8, -6 to -1, +1 to +6, +8 to +20, and +22 to +26. The transmitting STA may additionally map the signal of {-1, -1, -1, 1} to the subcarrier index {-28, -27, +27, +28}. The above signal can be used for channel estimation in the frequency domain corresponding to {-28, -27, +27, +28}.

[0153] The transmitting STA can construct the RL-SIG with the same structure as the L-SIG. BPSK modulation is applied to the RL-SIG. Based on the existence of the RL-SIG, the receiving STA can identify whether the received PPDU is a HE PPDU or an EHT PPDU.

[0154] exist Fig.13 After the RL-SIG, a universal SIG (U-SIG) may be inserted. The U-SIG may be referred to by various names such as a first SIG field, a first SIG, a first type SIG, a control signal, a control signal field, and a first (type) control signal.

[0155] The U-SIG may include N bits of information and may include information for identifying the EHT PPDU type. For example, the U-SIG may be configured based on two symbols (e.g., two consecutive OFDM symbols). Each symbol of the U-SIG (e.g., OFDM symbol) may have a duration of 4us, and the U-SIG may have a total duration of 8us. 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.

[0156] For example, through U-SIG (or U-SIG field), A-bit information (e.g., 52 uncoded bits) may be transmitted, the first symbol of U-SIG (e.g., U-SIG-1) may transmit the first X-bit information (e.g., 26 uncoded bits) of the total A-bit information, and the second symbol of U-SIG (e.g., U-SIG-2) may transmit the remaining Y-bit information (e.g., 26 uncoded bits) of the total A-bit information. For example, the transmitting STA may obtain the 26 uncoded bits included in each U-SIG symbol. The transmitting STA may generate 52 coded bits by performing convolution encoding (e.g., BCC encoding) based on a rate of R=1 / 2, and perform interleaving on the 52 coded bits. The transmitting STA may generate 52 BPSK symbols assigned to each U-SIG symbol by performing BPSK modulation on the interleaved 52 coded bits. Except for DC index 0, one U-SIG symbol may be transmitted based on 56 tones (subcarriers) from subcarrier index -28 to subcarrier index +28. The 52 BPSK symbols generated by the transmitting STA may be transmitted based on the remaining tones (subcarriers) except for the pilot tones -21, -7, +7, and +21.

[0157] For example, the A-bit information (e.g., 52 uncoded bits) sent by the U-SIG includes a CRC field (e.g., a 4-bit field) and a tail field (e.g., a 6-bit length field). The CRC field and the tail field may be sent through the second symbol of the U-SIG. The CRC field may be constructed based on the 26 bits of the first symbol allocated to the U-SIG and the remaining 16 bits in the second symbol excluding the CRC / tail field, and may be constructed based on a conventional CRC calculation algorithm. In addition, the tail field may be used to terminate the trellis of the convolutional decoder, and, for example, the tail field may be set to 0.

[0158] The bit information (e.g., 52 uncoded bits) transmitted by the U-SIG (or U-SIG field) may be divided into version-dependent bits and version-independent bits. For example, the size of the version-independent bits may be fixed or variable. For example, the version-independent bits may be assigned only to the first symbol of the U-SIG, or the version-independent bits may be assigned to the first symbol and the second symbol of the U-SIG. For example, the version-independent bits and the version-dependent bits may be referred to as various names such as the first control bit and the second control bit.

[0159] For example, the version-independent bit of the U-SIG may include a 3-bit physical layer version identifier (PHY version identifier). For example, the 3-bit PHY version identifier may include information related to the PHY version of the transmitted / received PPDU. For example, the first value of the 3-bit PHY version identifier may indicate that the transmitted / received PPDU is an EHT PPDU. In other words, when transmitting an EHT PPDU, the transmitting STA may set the 3-bit PHY version identifier to a first value. In other words, the receiving STA may determine that the received PPDU is an EHT PPDU based on the PHY version identifier having the first value.

[0160] For example, the version-independent bits of the U-SIG may include a 1-bit UL / DL flag field. A first value of the 1-bit UL / DL flag field is associated with UL communication, and a second value of the UL / DL flag field is associated with DL communication.

[0161] For example, the version-independent bits of the U-SIG may include information about a transmit opportunity length (TXOP) and information about a BSS color ID.

[0162] For example, if the EHT PPDU is classified into various types (e.g., EHT PPDU associated with SU mode, EHT PPDU associated with MU mode, EHT PPDU associated with TB mode, EHT PPDU associated with extended range transmission, etc.), information about the EHT PPDU type may be included in the version-related bit of the U-SIG.

[0163] For example, U-SIG may include information about the following items: 1) a bandwidth field containing information about the bandwidth, 2) a field containing information about the MCS scheme applied to the EHT-SIG, 3) an indication field containing information related to whether the DCM technology is applied to the EHT-SIG, 4) a field containing information about the number of symbols used for the EHT-SIG, 5) a field containing information about whether the EHT-SIG is constructed on all frequency bands, 6) a field containing information about the type of EHT-LTF / STF, and 7) a field indicating the EHT-LTF length and the CP length.

[0164] Preamble puncturing can be applied to Fig.13 PPDU. Preamble puncturing may mean the transmission of a PPDU in which no signal exists in one or more 20 MHz subchannels in the bandwidth of the PPDU. Preamble puncturing may be applied to a PPDU sent to one or more users. For example, for an EHT MU PPDU in OFDMA transmission with a bandwidth greater than 40 MHz and a non-OFDMA transmission with a bandwidth of 80 MHz and 160 MHz, the resolution of preamble puncturing may be 20 MHz. That is, in the above scenario, puncturing of subchannels less than 242 tone RUs is not allowed. In addition, for an EHT MU PPDU in a non-OFDMA transmission with a bandwidth of 320 MHz, the resolution of preamble puncturing may be 40 MHz. That is, puncturing of subchannels less than 484 tone RUs in a 320 MHz bandwidth is not allowed. In addition, preamble puncturing may not be applied to the primary 20 MHz channel in the EHT MU PPDU.

[0165] Information about the preamble puncturing applied to the PPDU may be included in the U-SIG and / or the EHT-SIG. For example, the first field of the U-SIG may include information about the continuous bandwidth of the PPDU, and the second field of the U-SIG may include information about the preamble puncturing applied to the PPDU.

[0166] For example, the U-SIG and the EHT-SIG may include information about preamble puncturing based on the following method. If the bandwidth of the PPDU exceeds 80 MHz, the U-SIG may be independently constructed in units of 80 MHz. For example, if the bandwidth of the PPDU is 160 MHz, the PPDU may include a first U-SIG for a first 80 MHz band and a second U-SIG for a second 80 MHz band. In this case, the first field of the first U-SIG includes information about the 160 MHz bandwidth, and the second field of the first U-SIG includes information about the preamble puncturing applied to the first 80 MHz band (i.e., information about the preamble puncturing pattern). In addition, the first field of the second U-SIG includes information about the 160 MHz bandwidth, and the second field of the second U-SIG includes information about the preamble puncturing applied to the second 80 MHz band (i.e., information about the preamble puncturing pattern). The EHT-SIG after the first U-SIG may include information about preamble puncturing applied to the second 80 MHz frequency band (i.e., information about the preamble puncturing pattern), and the EHT-SIG after the second U-SIG may include information about preamble puncturing applied to the first 80 MHz frequency band (i.e., information about the preamble puncturing pattern).

[0167] Additionally or alternatively, the U-SIG and the EHT-SIG may include information about preamble puncturing based on the following method. The U-SIG may include information about preamble puncturing of all bands (ie, information about a preamble puncturing pattern). That is, the EHT-SIG does not include information about preamble puncturing, and only the U-SIG may include information about preamble puncturing (ie, information about a preamble puncturing pattern).

[0168] The U-SIG can be constructed in units of 20MHz. For example, if an 80MHz PPDU is constructed, the U-SIG can be duplicated. That is, the same 4 U-SIGs can be included in the 80MHz PPDU. PPDUs with bandwidths exceeding 80MHz can include different U-SIGs.

[0169] Fig.13 The EHT-SIG may include control information for the receiving STA. The EHT-SIG may be transmitted through at least one symbol, and one symbol may have a length of 4us. Information on the number of symbols used for the EHT-SIG may be included in the U-SIG.

[0170] The EHT-SIG may include Fig.11 and Fig.12 The technical features of HE-SIG-B are described. For example, Figure 8 As in the example of , the EHT-SIG may include a common field and a user-specific field. The common field of the EHT-SIG may be omitted, and the number of user-specific fields may be determined based on the number of users.

[0171] As in Fig.11 As in the example of , the common field of EHT-SIG and the user-specific field of EHT-SIG can be encoded separately. One user block field included in the user-specific field can contain information for two user fields, but the last user block field included in the user-specific field can contain one or two user fields. That is, one user block field of EHT-SIG can contain up to two user fields. As in Fig.12 As in the example of , each user field may be associated with a MU-MIMO allocation or a non-MU-MIMO allocation.

[0172] With Fig.11 In the same manner as in the example of , the common field of the EHT-SIG may include a CRC bit and a tail bit. The length of the CRC bit may be determined as 4 bits, and the length of the tail bit may be determined as 6 bits and may be set to 000000.

[0173] As in Fig.11As in the example of , the common field of the EHT-SIG may include RU allocation information. The RU allocation information may be information about the locations of the RUs to which multiple users (ie, multiple receiving STAs) are allocated. The RU allocation information may be configured in units of 9 bits (or N bits).

[0174] A mode in which the common field of the EHT-SIG is omitted may be supported. A mode in which the common field of the EHT-SIG is omitted may be referred to as a compressed mode. When the compressed mode is used, multiple users of the EHT PPDU (ie, multiple receiving STAs) may decode the PPDU (eg, the data field of the PPDU) based on non-OFDMA. That is, multiple users of the EHT PPDU may decode the PPDU (eg, the data field of the PPDU) received via the same frequency band. When the non-compressed mode is used, multiple users of the EHT PPDU may decode the PPDU (eg, the data field of the PPDU) based on OFDMA. That is, multiple users of the EHT PPDU may receive the PPDU (eg, the data field of the PPDU) via different frequency bands.

[0175] The EHT-SIG may be constructed based on various MCS schemes. As described above, information related to the MCS scheme applied to the EHT-SIG may be included in the U-SIG. The EHT-SIG may be constructed based on the DCM scheme. The DCM scheme may reuse the same signal on two subcarriers to provide an effect similar to frequency diversity, reduce interference, and improve coverage. For example, modulation symbols applying the same modulation scheme may be repeatedly mapped on available tones / subcarriers. For example, a modulation symbol (e.g., a BPSK modulation symbol) applying a specific modulation scheme may be mapped to the first continuous half tone (e.g., the 1st to the 26th tone) among the N data tones (e.g., 52 data tones) allocated for the EHT-SIG, and a modulation symbol (e.g., a BPSK modulation symbol) applying the same specific modulation scheme may be mapped to the remaining continuous half tones (e.g., the 27th to the 52nd tone). That is, the modulation symbol mapped to the 1st tone and the modulation symbol mapped to the 27th tone are the same.

[0176] As described above, information related to whether the DCM scheme is applied to the EHT-SIG (eg, a 1-bit field) may be included in the U-SIG. Fig.13 The EHT-STF can be used to enhance automatic gain control (AGC) estimation in a MIMO environment or an OFDMA environment. Fig.13 The EHT-LTF can be used to estimate channels in a MIMO environment or an OFDMA environment.

[0177] Information about the type of STF and / or LTF (including information about a guard interval (GI) applied to LTF) may be included in Fig.13 The U-SIG field and / or EHT-SIG field of the RFID tag may be used.

[0178] Can be based on Figures 8 to 10 Example construction of RU allocation Fig.13 PPDU (ie, EHT PPDU).

[0179] For example, based on Figure 8 The RU constructs an EHT PPDU to be sent on the 20 MHz band, that is, a 20 MHz EHT PPDU. Figure 8 As shown in , the RU positions of the EHT-STF, EHT-LTF, and data fields included in the EHT PPDU can be determined. Fig. 9 The RU constructs an EHT PPDU to be sent on the 40 MHz band, that is, a 40 MHz EHT PPDU. Fig. 9 As shown in , RU positions of EHT-STF, EHT-LTF, and data fields included in the EHT PPDU may be determined.

[0180] Can be based on Fig.10 The RU constructs an EHT PPDU to be sent on the 80 MHz band, that is, an 80 MHz EHT PPDU. Fig.10 As shown in , RU positions of EHT-STF, EHT-LTF, and data fields included in the EHT PPDU may be determined. Fig.10 The tone plan for 80 MHz in may correspond to Fig. 9 Two repetitions of the tone plan for 40 MHz.

[0181] The tone plan for 160 / 240 / 320MHz can be repeated multiple times Fig. 9 or Fig.10 The mode is configured in the form of.

[0182] Fig.13 A PPDU can be identified as an EHT PPDU based on the following method.

[0183] The receiving STA may determine the type of the received PPDU as an EHT PPDU based on the following. For example, when 1) the first symbol after the L-LTF signal of the received PPDU is BPSK, 2) the RL-SIG that repeats the L-SIG of the received PPDU is detected, and 3) the result of applying the modulo 3 calculation to the value of the length field of the L-SIG of the received PPDU (i.e., the remainder after division by 3) is detected as 0, the received PPDU may be determined to be an EHT PPDU. When the received PPDU is determined to be an EHT PPDU, the receiving STA may determine the type of the received PPDU as an EHT PPDU based on Fig.13 In other words, the receiving STA can determine that the received PPDU is an EHT PPDU based on 1) the first symbol (BSPK) after the L-LTF signal, 2) the RL-SIG that is adjacent to the L-SIG field and is the same as the L-SIG, and 3) the L-SIG including the length field in which the result of applying modulo 3 is set to 0.

[0184] For example, the receiving STA may determine the type of the received PPDU as the HE PPDU based on the following: For example, when 1) the first symbol after the L-LTF signal is BPSK, 2) the RL-SIG repeating the L-SIG is detected, and 3) the result of applying modulo 3 to the length value of the L-SIG is detected as 1 or 2, the received PPDU may be determined as the HE PPDU.

[0185] For example, the receiving STA may determine the type of the received PPDU as non-HT, HT, and VHT PPDU based on the following: For example, when 1) the first symbol after the L-LTF signal is BPSK and 2) the RL-SIG repeating the L-SIG is not detected, the received PPDU may be determined as non-HT, HT, and VHT PPDU.

[0186] In addition, if the receiving STA detects that the RL-SIG of the L-SIG is repeated in the received PPDU, it can be determined that it is a HE PPDU or an EHT PPDU. In this case, if the rate (6Mbps) check fails, the received PPDU can be determined as a non-HT, HT, or VHT PPDU. If the rate (6Mbps) check and parity check pass, if the result of applying modulo 3 to the length value of the L-SIG is detected as 0, the received PPDU can be determined as an EHT PPDU, and if the result of the length modulo 3 is not 0, the received PPDU can be determined as an HE PPDU.

[0187] Fig.13 The PPDU can be used to send and receive various types of frames. For example, Fig.13 The PPDU can be used to (simultaneously) send and receive one or more of control frames, management frames, or data frames.

[0188] Hereinafter, U-SIG included in the EHT PPDU will be described in more detail.

[0189] For 40MHz EHT PPDU or extended range (ER) preamble, the U-SIG content is the same in both 20MHz subchannels. For 80MHz EHT PPDU or ER preamble, the U-SIG content is the same in all unpunctured 20MHz subchannels. For 160 / 320MHz EHT PPDU or ER preamble, the U-SIG content is the same on all unpunctured 20MHz subchannels within each 80MHz subblock and may be different from the U-SIG content in other 80MHz subblocks.

[0190] The U-SIG-1 part of the U-SIG of the EHT MU PPDU may include a PHY version identifier (B0-B2), BW (B3-B5), UL / DL (B6), BSS color (B7-B12), TXOP (B13-B19), discard (B20-B24), and verification (B25).

[0191] Also, the U-SIG-2 part of the EHT MU PPDU may include PPDU type and compression mode (B0-B1), verification (B2), puncturing channel information (B3-B7), verification (B8), EHT-SIG MCS (B9-B10), the number of EHT-SIG symbols (B11-B15), CRC (B16-B19), and tail (B20-B25).

[0192] For example, assume that the UL / DL field value is set to 0. When the PPDU Type and Compression Mode (B0-B1) field value of the U-SIG-2 part is 0, this indicates DL OFDMA transmission. When the PPDU Type and Compression Mode (B0-B1) field value of the U-SIG-2 part is 1, this indicates EHT SU transmission or EHT sounding NDP. When the PPDU Type and Compression Mode (B0-B1) field value of the U-SIG-2 part is 2, this indicates non-OFDMA DL MU-MIMO transmission.

[0193] As another example, assume that the UL / DL field value is set to 1. When the PPDU Type and Compression Mode (B0-B1) field value of the U-SIG-2 part is 0, this may indicate a TB PPDU (e.g., UL OFDMA or UL-non-OFDMA). And, when the PPDU Type and Compression Mode (B0-B1) field value of the U-SIG-2 part is 1, this may indicate an EHT SU transmission or an EHT sounding NDP.

[0194] Here, an example of a 5-bit punctured channel indication for a non-OFDMA case in an EHT MU PPDU is shown below in Table 1.

[0195] [Table 1]

[0196]

[0197]

[0198] In the puncturing pattern of Table 1, 1 represents a non-punctured subchannel, and x represents a punctured subchannel. The puncturing granularity of 80 MHz and 160 MHz PPDU bandwidths may be 20 MHz, and the puncturing granularity of 320 MHz PPDU bandwidth may be 40 MHz.

[0199] Next, the U-SIG-1 part of the U-SIG of the EHT TB PPDU may include a version identifier (B0-B2), BW (B3-B5), UL / DL (B6), BSS color (B7-B12), TXOP (B13-B19), and ignore (B20-B25), and the U-SIG-2 part may include a PPDU type and compression mode (B0-B1), verification (B2), spatial multiplexing 1 (B3-B6), spatial multiplexing 2 (B7-B10), ignore (B11-B15), CRC (B16-B19), and tail (B20-B25).

[0200] As described above, the U-SIG field of the EHT MU PPDU includes 5-bit puncturing channel information, but the EHT TB PPDU does not include puncturing channel information. This is because it is assumed that the EHT TB PPDU is constructed according to the resource allocation indicated by the trigger frame or TRS control information, so that the STA does not need to notify the AP of the resource information of the EHT TB PPDU.

[0201] Fig.14 An example format of a trigger frame to which the present disclosure may be applied is shown.

[0202] The trigger frame may allocate resources for the transmission of one or more TB PPDUs and request the transmission of a TB PPDU. The trigger frame may also include other information required for the STA to send a TB PPDU in response. The trigger frame may include common information and user information list fields in the frame body.

[0203] The common information (info) field is information that is generally applied to the transmission of one or more TB PPDUs requested by a trigger frame, such as trigger type, UL length, presence or absence of subsequent trigger frames (e.g., more TFs), CS (channel sensing) request, UL BW (bandwidth), HE / EHT P160, special user information field flag, etc.

[0204] The 4-bit Trigger Type subfield may have a value from 0 to 15. Among them, the value 0, value 1, value 2, value 3, value 4, value 5, value 6, and value 7 of the Trigger Type subfield are defined to correspond to Basic, Beamforming Report Poll (BFRP), Multi-User Block Acknowledgement Request (MU-BAR), Multi-User Request to Send (MU-RTS), Buffer Status Report Poll (BSRP), Multicast with Retry (GCR), MU-BAR, Bandwidth Query Report Poll (BQRP), and NDP Feedback Report Poll (NFRP), respectively, and values ​​8 to 15 are defined as reserved.

[0205] Among the common information, the trigger-related common information subfield may include information that is optionally included based on the trigger type.

[0206] A special user information field may be included in the trigger frame. The special user information field does not include user-specific information but includes extended common information that is not provided in the common information field.

[0207] A user information list includes zero or more user information fields. Fig.14 An example of the EHT variant user information field format is shown.

[0208] The AID12 subfield basically indicates that it is a user information field of the STA with the corresponding AID. In addition, if the AID12 field has a specific predetermined value, it can be used for other purposes, such as allocating a random access (RA)-RU or being configured as a special user information field. The special user information field is a user information field that does not include user-specific information but includes extended public information that is not provided in the common information field. For example, the special user information field can be identified by the AID12 value 2007, and the special user information field flag subfield within the common information field can indicate whether the special user information field is included.

[0209] The RU allocation subfield may indicate the size and location of the RU / MRU. To this end, the RU allocation subfield may be interpreted together with the PS160 (primary / secondary 160 MHz) subfield of the user information field and the UL BW subfield of the common information field.

[0210] Multiple Access Point (MAP) Operation

[0211] Hereinafter, examples of the present disclosure for multiple access point (MAP) operations are described.

[0212] MAP operation may be defined as an operation between a master AP (or an AP performing sharing) and a slave AP (or an AP being shared).

[0213] The master AP initiates and controls MAP operations for transmission and reception between multiple APs. The master AP groups slave APs and manages links with the slave APs so that information can be shared between the slave APs. The master AP manages information about the BSS configured by the slave APs and information about the STAs associated with the BSS.

[0214] The slave AP may be associated with the master AP and share control information, management information, and data traffic with each other. The slave AP performs the same basic function of an AP capable of establishing a BSS in a wireless LAN.

[0215] A STA in MAP operation may associate with a slave AP or a master AP to configure a BSS.

[0216] In a MAP environment, a master AP and a slave AP may perform direct transmission and reception with each other. A master AP and a STA may not perform direct transmission and reception with each other. A slave AP (e.g., a slave AP associated with a STA) may perform direct transmission and reception with a STA. One of the slave APs may become a master AP.

[0217] MAP operation is a technology in which one or more APs transmit and receive information with one or more STAs. For example, coordinated-time division multiple access (C-TDMA) that divides allocations between APs along the time axis, coordinated-orthogonal frequency division multiple access (C-OFDMA) that divides allocations between APs along the frequency axis, and coordinated-spatial multiplexing (C-SR) using spatial multiplexing can be applied to MAP operation. Alternatively, coordinated beamforming (C-BF) or joint beamforming technology that collaboratively performs simultaneous transmission and reception can also be applied to MAP operation.

[0218] Fig.15 It is a diagram for explaining various transmission and reception techniques in a MAP environment to which the present disclosure can be applied.

[0219] As in the conventional method, when the BSS AP transmits to the BSS STA, it can be called STX (Single Transmission). In STX, there is a problem of reducing the performance of transmission and reception of users / STAs located at the edge of the cell due to interference with neighboring APs. Fig.15 As shown in (a), when AP1 and AP2 transmit to STA1 and STA2 respectively, at the same time in the same frequency bandwidth, a conflict may occur with respect to the wireless medium.

[0220] In MAP technology, performance can be improved by reducing inter-symbol interference (ISI) through cooperation between neighboring APs or by performing joint transmission. Fig.15 In the C-OFDMA method of (b), interference can be avoided by simultaneously allowing AP1 to transmit to STA1 in the first bandwidth and allowing AP2 to transmit to STA2 in the second bandwidth.

[0221] Fig.15 The example of (c) illustrates a collaborative beamforming or nulling technique in which interference to AP2 and / or STA2 is nulled when AP1 transmits to STA1 and interference to AP1 and / or STA1 is nulled when AP2 transmits to STA2.

[0222] Fig.15 (d) shows an AP selection method in which an AP having a good channel condition among neighboring APs performs transmission.

[0223] Can be applied as Fig.15 As in the example of (e), multiple APs cooperate to perform joint transmission (JTX) or joint reception (JRX) to transmit or receive simultaneously, and further, joint MU-MIMO can be supported.

[0224] Coordinated Spatial Multiplexing (C-SR) Technology

[0225] When the SP technology is applied to the basic wireless LAN system, the state of the BSS AP can be sent (by the BSS AP) through a trigger frame or TB PPDU, etc. If the OBSS AP can send data while satisfying Equation 1, the C-SR technology can control the power of the BSS AP / STA and the power of the OBSS AP / STA.

[0226] [Formula 1]

[0227] TxPower PSRT，总 -10×log 10 N PSRT，nonpunc ≤PSR min -RPL PSRR，20MHz

[0228] In Formula 1, PSR is the SR value of the trigger frame and the SIG field of the TB PPDU, and RPL may represent received signal power.

[0229] In order to apply the C-SR technology, the interference situation of the BSS AP / STA and / or OBSS AP / STA must be confirmed.

[0230] The following describes the process of performing C-SR with OBSS AP / STA from the perspective of BSS AP / STA. Here, BSS AP is a sharing AP (Sharing AP) or a shared AP (Shared AP), and OBSS AP can be interpreted as a shared AP that performs C-SR together.

[0231] The C-SR process may include a pre-process, a shared AP candidate selection process, a C-SR establishment process, and a data transmission process.

[0232] The pre-process refers to a process for pre-reporting and collecting information to be exchanged for C-SR operation. The AP / STA can obtain the channel information of the BSS / OBSS AP / STA based on the direction of the frame (e.g., DL direction or UL direction) that is the target of the C-SR operation.

[0233] For example, the BSS STA may obtain channel information from a persistent packet or an NDP sounding frame of the OBSS AP and transmit the obtained channel information to the BSS AP.

[0234] In addition, in order to apply C-SR in RU units, it may be necessary to obtain channel information in RU units rather than in the full band. For example, the BSS STA can obtain channel information in RU units from the NDP detection frame of the OBSS AP and report the obtained channel information in RU units to the BSS AP.

[0235] In case of the shared AP candidate selection process, the shared AP may select shared AP candidates by collecting information about neighboring APs.

[0236] For example, assuming that zeroing is not required based on the distance between APs (e.g., the distance between APs is not too close). In this case, if the RSSI measurement value associated with the AP is within a specific value (e.g., -82dBM), the shared AP can select the shared AP from the APs with busy channel status.

[0237] The C-SR establishment process may include a process for selecting a shared AP to exchange C-SR data (before starting C-SR data transmission) and confirming whether C-SR data can be sent or received using the selected shared AP. The C-SR establishment process may be performed before the SIFS of the C-SR data transmission process.

[0238] Some parts of the C-SR establishment process may be omitted. For example, at least one of a process for checking whether the selected shared AP can send and receive C-SR data or a process for selecting a shared AP with which to exchange C-SR data may be omitted.

[0239] For example, when a trigger frame for C-SR establishment is sent to a shared AP (by a sharing AP), the shared AP that is capable of sending and receiving C-SR data may send a confirmation message to the sharing AP indicating whether C-SR data sending and receiving is possible. Thus, the sharing AP may confirm whether the shared AP is capable of sending and receiving C-SR data.

[0240] The data transmission process may include a process for sending a C-SR trigger frame (or a separate DL frame) for C-SR data transmission and a process for the OBSS / BSS AP to send and receive C-SR data based on the C-SR trigger frame. Fig.14 Configure the C-SR trigger frame according to the trigger frame shown in .

[0241] Here, the C-SR trigger frame (or a separate DL frame) may include basic information for performing a C-SR operation (i.e., C-SR data transmission and reception). For example, the basic information may include information such as the transmit power (Tx power) of the BSS AP (or shared AP), the Tx power limit value to be used by the shared AP, the acceptable interference level of the BSS AP (or shared AP), the TXOP duration, the DL frame length, the DL / UL type of the sharing / shared AP, and the like.

[0242] The shared AP receiving the trigger frame may transmit its own data based on the C-SR technology, or may include C-SR information in a trigger frame for data transmission of OBSS / BSS STA and transmit it.

[0243] Method for obtaining channel information in pre-process during C-SR process

[0244] Hereinafter, a method of acquiring channel information in a pre-process during a C-SR process is described. The AP / STA should acquire the channel information of the BSS / OBSS AP / STA based on the direction of the frame to which the C-SR technology is to be applied (i.e., DL direction or UL direction).

[0245] Here, a method in which the BSS AP / STA and the OBSS AP / STA adjust Tx power using a channel value (eg, interference value) of the BSS and a method for implementing C-SR may be implemented in various manners.

[0246] Method 1

[0247] like Fig.16 As illustrated in (a), method 1 relates to a method for obtaining channel information when performing DL transmission of a BSS AP and DL transmission of an OBSS AP (hereinafter, "DL / DL"). In order for the BSS AP to transmit a DL frame using the C-SR technology in the DL / DL situation, interference information of the OBSS AP to the BSS STA is required. Therefore, the BSS STA can measure the channel value of the DL frame of the OBSS AP and report it to the BSS AP.

[0248] For example, the BSS STA may measure the channel value of an ongoing packet (e.g., a beacon frame, etc.) of the OBSS AP. That is, the OBSS AP may send the ongoing packet to the BSS STA, and the BSS STA may obtain the channel value through the received ongoing packet. The operation of obtaining the channel value based on the ongoing packet may be performed by an instruction of the BSS AP or according to the decision of the BSS STA.

[0249] As another example, an NDP sounding process (hereinafter, "OBSS NDP sounding") may be performed between an OBSS AP and a BSS STA under the guidance of the BSS AP (or shared AP). That is, the BSS STA may obtain a channel value based on the NDP transmitted by the OBSS AP.

[0250] When describing the present disclosure, a “channel value” may include at least one of a received signal strength indication (RSSI), an Rx power indicator (RPI), an average noise power indicator (ANPI), an idle power indicator (IPI), an Rx channel power indicator (RCPI), or an Rx signal-to-noise ratio indicator (RSNI).

[0251] In addition, the channel value measured by the BSS / OBSS AP / STA in the present disclosure may include a total channel value for a frequency band indicated (by the BSS / OBSSAP), or a channel value for an indicated / allocated RU.

[0252] Method 2

[0253] like Fig.16As illustrated in (b) of FIG. 1 , method 2 relates to a method for obtaining channel information when performing UL reception of a BSS AP and DL transmission of an OBSS AP (hereinafter, “UL / DL”). In the UL / DL scenario, in order for a BSS STA to transmit an UL frame using a C-SR technique, interference information of an OBSS AP directed to the BSS AP may be required. That is, the BSS AP may measure a channel value of a DL frame from an OBSS AP.

[0254] For example, the BSS AP may measure the channel value of an ongoing packet (eg, beacon frame, etc.) of the OBSS AP. In this case, since the BSS AP directly measures / obtains the channel value, a separate reporting process for the channel value may not be required.

[0255] As another example, the BSS AP may obtain the channel value through the OBSS NDP sounding process. Since the measurement value feedback process of the OBSS NDP for C-SR is not required in the UL / DL case, the NDP sounding process may be completed through OBSS NDP transmission or ACK transmission of the BSS AP for OBSS NDP transmission.

[0256] As another example, when the OBSS sounding process is performed considering a DL / DL situation, the OBSS sounding process may include a process in which the BSS STA transmits feedback after the OBSS AP transmits the NDP.

[0257] Method 3

[0258] like Fig.16 As illustrated in (c), method 3 relates to a method for obtaining channel information when performing DL transmission of a BSS AP and UL reception of an OBSS AP (hereinafter, "DL / UL"). In the DL / UL scenario, the BSS AP may need interference information of the OBSS STA to the BSS STA to send a DL frame using the C-SR technology.

[0259] Therefore, the BSS STA can measure and report the channel values ​​for all OBSS STAs supporting the C-SR process. At this time, the BSS STA can use the ongoing grouping or OBSS NDP sounding process.

[0260] On the other hand, STAs may not be able to measure and report channel values ​​as smoothly as APs. Since there is no regular ongoing grouping and as many measurements as the number of OBSS STAs are required, the feedback overhead value of BSS STAs may increase in DL / UL situations. Therefore, C-SR technology may not be allowed in DL / UL situations.

[0261] Method 4

[0262] like Fig.16 As illustrated in (d), method 4 relates to a method for obtaining channel information when performing UL reception of a BSS AP and UL reception of an OBSS AP (hereinafter, "UL / UL"). In the UL / UL case, the BSS STA may need interference information of the OBSS AP to the BSS AP to send a UL frame using the C-SR technology.

[0263] In the "DL / DL" case, the BSS STA may report the interference channel measurement value from the OBSS AP to the BSS AP. Therefore, the OBSS AP may receive the channel measurement value from the BSS AP based on the OBSS STA. The OBSS AP may send the interference channel measurement value received from the OBSS STA to the BSS AP. For example, the OBSS AP may send the interference channel measurement value to the BSS AP via a control message over the air or on a backbone network.

[0264] Therefore, the BSS AP may instruct the BSS STA to adjust the Tx power for C-SR through a trigger frame. That is, in the UL / UL scenario, C-SR transmission may require a data sharing process between the BSS AP and the OBSS AP.

[0265] In a basic wireless LAN system, within the duration of a BSS STA sending a HE TB PPDU to a BSS AP, at least one OBSS STA may send a PPDU and / or an ACK for the PPDU. The present disclosure describes a method for determining a channel and time for sending and receiving an ACK between an OBSS AP / STA when sending and receiving a DL frame between a BSS AP / STA.

[0266] Hereinafter, "duration" may refer to a duration in the time domain (i.e., a time period). That is, the duration for the BSS STA to send the HE TB PPDU to the BSS AP may refer to the duration in the time domain for the BSS STA to send the HE TB PPDU to the BSS AP. However, the present invention is not limited thereto, and "duration" may also refer to a duration in the frequency domain.

[0267] Fig.17is a diagram for describing an operation performed by a first STA according to an embodiment of the present disclosure. In the following, the first STA may be an OBSS STA, the second STA may be a BSS STA, the first AP may be an OBSS AP (or a shared AP), and the second AP may be a BSS AP (or a shared AP). That is, the first AP and the second AP may perform a multi-AP operation based on (C-)SR.

[0268] A first STA may receive a first downlink (DL) frame from a first access point (AP) ( S1710 ).

[0269] For example, when the first STA receives the first DL frame from the first AP, the second STA can receive the second DL frame from the second AP. As another example, the second STA can receive the second DL frame before the first STA receives the first DL frame, and the second STA can receive the second DL frame after the first STA completes receiving the first DL frame.

[0270] The first STA may transmit an uplink (UL) frame for a first DL frame to the first AP within or after a specific duration (S1720).

[0271] Here, the specific duration (e.g., a specific time period) may include a section in which the second DL frame is sent from the second AP to the second STA. For example, the first STA may send a first UL frame (e.g., a UL ACK / BA frame, etc.) within the duration in which the second DL frame is sent from the second AP to the second STA. As another example, the first STA may be configured / instructed / defined not to send the first UL frame in the section in which the second DL frame is sent from the second AP to the second STA, and may send the first UL frame after the duration.

[0272] Specifically, based on the first STA being a STA capable of performing a spatial multiplexing (SR) operation, the first STA may be permitted to transmit the first UL frame in a specific section.

[0273] For example, the first AP may check whether the first STA has SR capability. If it is confirmed that the first STA is a STA capable of performing SR operation, the first AP may allow the first UL frame to be sent within a specific duration. For example, the first AP may send information indicating that immediate transmission of the first UL frame is permitted to the first STA (e.g., information indicating that transmission of the first UL frame is permitted after SIFS after the first DL frame is sent).

[0274] Therefore, the first STA may obtain the transmission power of the first UL frame based on the interference level of the second DL frame transmitted from the second AP to the second STA. The first STA may transmit the first UL frame to the first AP (within a specific duration) using the obtained transmission power.

[0275] In another example of the present disclosure, based on the fact that the first STA is a STA that cannot perform SR operation, the first UL frame transmission of the first STA may be permitted after a specific duration. That is, if it is determined that the first STA is a STA that cannot perform SR operation, the first AP may not permit the first UL frame transmission within a specific duration. For example, the first AP may send information indicating a delay in the transmission of the first UL frame to the first STA. Therefore, the first STA may transmit the first UL frame after a specific duration.

[0276] Additionally or alternatively, the end time of the first DL frame may be aligned with the end time of the second DL frame.Therefore, interference caused by transmission of the first UL frame may not affect transmission and reception of the second DL frame.

[0277] Additionally or alternatively, a dedicated channel may be allocated (by the first AP and / or the second AP) for sending the first UL frame. The first STA may send the first UL frame to the first AP via the dedicated channel. In this case, the second AP may send the second DL frame to the second STA on a channel other than the dedicated channel.

[0278] When a dedicated channel is allocated, the first STA can independently / regardlessly transmit the first UL frame in a specific duration. That is, the first STA can freely transmit the first UL frame through the allocated dedicated channel.

[0279] Additionally or alternatively, after the dedicated channel is allocated, the first STA may choose to send the first UL frame within a specific duration or after a specific time interval. For example, the first STA may send the first UL frame on the dedicated channel within a specific duration, but is not limited thereto. The first STA may send the first UL frame on the dedicated channel after a specific duration.

[0280] As an example of the present disclosure, the first AP or the second AP may send information to the first STA via a C-SR trigger frame, which sets a method for sending a first UL frame within a specific duration or after a specific duration (for example, a method for setting a dedicated channel, a method for checking the SR capability of the STA to determine whether sending the first UL frame within a specific duration is allowed, etc.).

[0281] However, this is merely one implementation, and the second AP may send information to the first AP / first STA through a C-SR trigger frame, the information setting a method for sending the first UL frame within or after a specific duration.

[0282] exist Fig.17 The method performed by the first STA described in the example of Figure 1 For example, Figure 1 One or more processors (102) of a first device (100) may be configured to receive a first DL frame from a first AP via one or more transceivers (106). One or more processors (102) may be configured to send a first UL frame for the first DL frame to a second AP via one or more transceivers (106) within or after a specific duration.

[0283] In addition, one or more memories (104) of the first device (100) may store instructions for executing the operation when executed by one or more processors (102). Fig.17 Instructions for the methods described in the examples.

[0284] Fig.18 is a diagram for explaining operations performed by a first PA according to one embodiment of the present disclosure.

[0285] The first AP may transmit a first downlink (DL) frame to a first station (STA) ( S1810 ).

[0286] For example, while the first AP sends the first DL frame to the first STA, the second AP can send the second DL frame to the second STA. As another example, the second AP can send the second DL frame before the first AP sends the first DL frame, and the second AP can send the second DL frame after the first AP completes sending the first DL frame.

[0287] The first AP may receive a first UL frame for a first DL frame from a first STA within or after a specific duration ( S1820 ).

[0288] For example, the first AP may receive information from the second AP that sets how to send the first UL frame within a specific duration or after a specific duration. As another example, the first AP may send information to the first STA that sets how to send the first UL frame within a specific duration or after a specific duration.

[0289] However, this is merely one embodiment, and a method of transmitting the first UL frame within a specific duration or after a specific duration may be predefined.

[0290] Already referred to Fig.17 S1720 describes an operation of receiving, by the first AP, a first UL frame for a first DL frame within a specific duration or within a specific segment, and thus any repeated description will be omitted.

[0291] exist Fig.18 The method performed by the first AP described in the example may be performed by Figure 1 For example, Figure 1 One or more processors (202) of the second device (200) may be configured to receive a first DL frame from a first STA through one or more transceivers (206). The one or more processors (202) may receive a first UL frame for the first DL frame from the first STA through one or more transceivers (206) within a specific duration or after a specific duration.

[0292] In addition, the one or more memories (204) of the second device (200) may store instructions for executing the operation when executed by the one or more processors (202). Fig.18 Instructions for the methods described in the examples.

[0293] As an example of the present disclosure, it is assumed that the BSS / OBSS AP / STA is based on Fig.19 The "DL / UL" illustrated in (a) performs a C-SR-based operation (i.e., an operation according to the above method 3). During the duration that the BSS AP (or shared AP) sends a DL frame to the BSS STA, the OBSS STA may send a UL frame including a ULACK / BA frame, etc., in response to the DL frame sent by the OBSS AP (or shared AP).

[0294] Here, if the interference level between the BSS STA and the OBSS STA is high, the BSS STA may not smoothly receive the BSS DL frame due to the OBSS UL frame transmission (ie, due to an interference effect according to the OBSS UL frame transmission).

[0295] In order to solve the above problem, a method for transmitting a UL frame of an OBSS STA during a duration in which a BSS AP transmits a DL frame to a BSS STA is described below.

[0296] Implementation Method 1

[0297] The transmission of OBSS UL frames (transmission from OBSS STA to OBSS AP) may be prohibited during the duration of the transmission of DL frames from BSS AP to BSS STA.

[0298] For example, when an OBSS AP sends a DL frame that requires an ACK response, it may set the ACK policy for ACK / BA frame transmission to "delayed ACK".

[0299] Specifically, if it is determined that the UL ACK / BA frame will be sent within the duration of sending the DL frame from the BSS AP to the BSS STA, or / and if the interference level between the BSS STA and the OBSS STA exceeds a threshold, the OBSS AP can instruct / configure the OBSS STA to send the UL ACK / BA frame after the duration of sending the DL frame from the BSS AP to the BSS STA.

[0300] Therefore, if the time point after SIFS after receiving the DL frame from the OBSS AP is within the duration of sending the DL frame from the BSS AP to the BSS STA, the OBSS STA may not send a UL frame (e.g., UL ACK / BA frame) for the DL frame within the duration according to the "delayed ACK" set by the OBSS AP. The OBSS STA may send a UL frame for the DL frame after the duration.

[0301] Additionally or alternatively, the end time of each of the OBSSDL frame / packet and the BSSDL frame / packet may be aligned. That is, the end time of the OBSSDL frame / packet sent by the OBSS AP may be set / defined to coincide with the end time of the BSSDL frame / packet sent by the BSSAP.

[0302] For example, if the packet length of one of the OBSSDL frame / packet or the BSSDL frame is shorter than the packet length of the other, padding bits and / or dummy signals may be added to the DL frame having the shorter packet length.

[0303] The operation / parameter according to Embodiment 1 can be applied to the operation based on C-SR as well as the operation based on C-SR.

[0304] Implementation Method 2

[0305] Only STAs that are capable of performing SR-based operations (SR-capable) may be configured / defined / instructed to send OBSS UL frames.

[0306] Specifically, the OBSS AP may check the SR capability of one or more OBSS STAs. For example, the OBSS AP may check the SR capability of one or more OBSS STAs by receiving a frame including fields (eg, SR capability-related fields) respectively indicating whether the OBSS STAs can perform SR-based operations.

[0307] The OBSS AP may allow OBSS UL frames to be sent only to OBSS STAs with SR capabilities.

[0308] For example, the OBSS AP may send a field (e.g., an "Immediate ACK" field, etc.) to the SR-capable OBSS STA indicating that its reception of the OBSS DL frame allows the immediate transmission of the OBSS UL frame. Therefore, the SR-capable OBSS STA may send an OBSS UL frame for the OBSS DL frame (received from the OBSS AP).

[0309] That is, even during the duration of sending DL frames from the BSS AP to the BSS STA, the OBSS STA with SR capability sends OBSS UL frames to the OBSS AP. For example, the OBSS STA with SR capability can determine and allow the interference information of the BSS DL frame to calculate the allowable Tx power. Then, the OBSS STA can send the OBSS UL frame with the calculated Tx power.

[0310] Furthermore, an OBSS STA that does not have SR capability may not be permitted to send an OBSS UL frame to the OBSS AP within the duration for which a DL frame is sent from the BSS AP to the BSS STA.

[0311] The operation / parameter according to Embodiment 1 can be applied not only to the operation based on C-SR but also to the operation based on C-SR.

[0312] Implementation 3

[0313] When performing C-SR-based operation, considering UL frame (e.g., UL ACK frame) transmission, RU for U transmission can be allocated to each AP. That is, BSS / OBSS AP / STA can send and receive UL frames by combining C-SR-based operation and C-OFDMA-based operation.

[0314] Specifically, a dedicated channel may be separately allocated for UL (control) frames (e.g., UL ACK frames, etc.). For example, the BSSAP may send DL frames to the BSS STA through a channel other than the dedicated channel. In this case, the OBSS AP may send DL frames to the OBSS STA based on the C-SR. The OBSS STA may send UL frames for DL ​​frames to the OBSS AP through a dedicated channel.

[0315] It may be fixed / limited to at least one of the above-mentioned implementation modes 1, 2, and 3, but is not limited thereto. The BSS / OBSS AP may select at least one of implementation modes 1, 2, and 3, and notify the BSS / OBSS STA to perform operations according to the selected implementation mode.

[0316] That is, the BSS / OBSS AP may apply / instruct / set an operation / parameter based on at least one of Embodiment 1, Embodiment 2, and Embodiment 3 to the BSS / OBSS STA.

[0317] For example, the BSS AP (e.g., shared AP) may select at least one of implementation modes 1, 2, and 3, and transmit information related to the selected implementation mode to the OBSS AP or / and the BSS / AP STA via a trigger frame for C-SR (i.e., C-SR trigger frame). The OBSS AP or / and the BSS / AP STA may perform an operation according to the information related to the selected implementation mode included in the C-SR trigger frame.

[0318] 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 regarded 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 a combination of some 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.

[0319] 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.

[0320] 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, for example, DRAM, SRAM, DDR RAM, or other random access solid-state storage devices, but is not limited thereto, and it may include non-volatile memory, such as, for example, 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.

[0321] Industrial Applicability

[0322] The method proposed in the present disclosure is mainly described based on an example applied to a system based on IEEE 802.11, but may 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 first station STA in a wireless LAN system, the method comprising the following steps: receiving a first downlink DL frame from a first access point AP; and sending a first uplink (UL) frame for the first DL frame to the first AP within or after a specific duration, The specific duration includes a duration for sending a second DL frame from the second AP to the second STA, and The first AP is an Overlapping Basic Service Set (OBSS) AP, and the second AP is a BSS AP.

2. The method according to claim 1, wherein: Based on the first STA being a STA capable of performing a spatial multiplexing SR operation, the first STA is permitted to send the first UL frame within the specific duration.

3. The method according to claim 2, wherein: After a SIFS after transmitting the first DL frame, information indicating that transmission of the first UL frame is permitted is received from the first AP.

4. The method according to claim 2, wherein: obtaining a transmission power of the first UL frame based on an interference level of the second DL frame transmitted from the second AP to the second STA, and The first UL frame is sent to the first AP using the obtained transmission power.

5. The method according to claim 1, wherein: Based on the first STA being a STA that is incapable of performing a spatial multiplexing (SR) operation, the first STA is permitted to transmit the first UL frame after the specific duration.

6. The method according to claim 5, wherein: Information indicating a delay in the transmission of the first UL frame is sent from the first AP to the first AP.

7. The method according to claim 1, wherein: An end time of the first DL frame is aligned with an end time of the second DL frame.

8. The method according to claim 1, wherein: allocating a dedicated channel for sending the first UL frame, and The first UL frame is transmitted from the first STA to the first AP through the dedicated channel within the specific time duration.

9. The method according to claim 8, wherein: The second DL frame is sent from the second AP to the second STA on any channel except the dedicated channel.

10. The method according to claim 1, wherein: Information on a method of configuring transmitting the first UL frame within or after the specific duration is received from the first AP or the second AP via a coordinated C-SR trigger frame.

11. The method according to claim 1, wherein: The first STA is an OBSS STA, and the second STA is a BSS STA.

12. A first station STA in a wireless LAN system, the first 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 first downlink DL frame from a first access point AP; and transmitting, by the at least one transceiver, a first uplink (UL) frame for the first DL frame to the first AP within a specific duration or after the specific duration, The specific duration includes a duration for sending a second DL frame from the second AP to the second STA, and The first AP is an Overlapping Basic Service Set (OBSS) AP, and the second AP is a BSS AP.

13. A method performed by a first access point (AP) in a wireless LAN system, the method comprising the following steps: Sending a first downlink DL frame to a first station STA; and receiving a first uplink (UL) frame for the first DL frame from the first STA within or after a specific duration, The specific duration includes a duration for sending a second DL frame from the second AP to the second STA, and The first AP is an Overlapping Basic Service Set (OBSS) AP, and the second AP is a BSS AP.

14. A first access point (AP) in a wireless LAN system, the first 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 a first downlink DL frame to a first station STA through the at least one transceiver; and receiving, by the at least one transceiver, a first uplink (UL) frame for the first DL frame from the first STA within a specific duration or after the specific duration, The specific duration includes a duration for sending a second DL frame from the second AP to the second STA, and The first AP is an Overlapping Basic Service Set (OBSS) AP, and the second AP is a BSS AP.

15. A processing device configured to control a first station STA in a wireless LAN system, the processing device comprising: at least one processor; as well as at least one computer memory operatively connected to the at least one processor and storing instructions that, upon execution by the at least one processor, perform operations comprising: receiving a first downlink DL frame from a first access point AP; and sending a first uplink (UL) frame for the first DL frame to the first AP within or after a specific duration, The specific duration includes a duration for sending a second DL frame from the second AP to the second STA, and The first AP is an Overlapping Basic Service Set (OBSS) AP, and the second AP is a BSS AP.

16. At least one non-transitory computer-readable medium storing at least one instruction, in, The at least one instruction executable by at least one processor controls a device in a wireless LAN system to: receiving a first downlink DL frame from a first access point AP; and sending a first uplink (UL) frame for the first DL frame to the first AP within or after a specific duration, The specific duration includes a duration for sending a second DL frame from the second AP to the second STA, and The first AP is an Overlapping Basic Service Set (OBSS) AP, and the second AP is a BSS AP.

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