Method and apparatus for transmitting and receiving PPDU within BSS group in wireless LAN system

Abstract

Disclosed are a method and an apparatus for operating in a wireless LAN system. According to an embodiment of the present disclosure, a method performed by a first STA in a wireless LAN system comprises the steps of: receiving, from a first access point (AP) included in a basic service set (BSS) group, a beacon frame including a specific BSSID; performing association on the BSS group based on the specific BSSID; and receiving a first physical layer protocol data unit (PPDU) from at least one AP included in the BSS group, in which the specific BSSID is a common BSSID for transmitting and receiving data to and from the at least one AP, and may receive a second PPDU from a second AP among the at least one AP based on the specific BSSID without performing an association procedure.

Description

Technical Field

[0001] The present disclosure relates to communication operations in a wireless local area network (WLAN) system, and more particularly, to a method and apparatus for transmitting and receiving a physical layer protocol data unit (PPDU) within a basic service set (BSS) group in a next generation wireless LAN 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] A technical problem of the present disclosure is to provide a method and apparatus for transmitting and receiving PPDU within a BSS group in a wireless LAN system.

[0006] A technical problem of the present disclosure is to provide a method and apparatus for supporting a seamless roaming operation within a BSS group without a separate association procedure in a wireless LAN system.

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

[0008] Technical Solution

[0009] According to one embodiment of the present disclosure, a method performed by a first station (STA) in a wireless LAN system may include: receiving a beacon frame including a specific BSSID from a first access point (AP) included in a BSS (Basic Service Set) group; performing association on the BSS group based on the specific BSSID; and receiving a first PPDU (Physical Layer Protocol Data Unit) from at least one AP included in the BSS group, and the specific BSSID may be a public BSSID for receiving and receiving data with at least one AP, and a second PPDU may be received from a second AP among the at least one AP based on the specific BSSID without performing an association process.

[0010] According to one embodiment of the present disclosure, a method performed by a first access point (AP) in a wireless LAN system may include: receiving a trigger frame from a representative AP, the trigger frame including a sending area and a sending method of a first PPDU (physical layer protocol data unit); sending the first PPDU to a first STA based on the trigger frame; receiving response information for the first PPDU from the first STA; and sending the response information for the first PPDU to the representative AP, and the SA (source address) or TA (sending address) of the first trigger frame may be set to a specific BSSID related to a BSS (basic service set) group including the first AP, and a second PPDU may be sent to the first STA from a second AP among multiple APs including the first AP based on the specific BSSID without performing an association process.

[0011] Technical Effects

[0012] According to various embodiments of the present disclosure, a method and apparatus for transmitting and receiving a PPDU within a BSS group in a wireless LAN system may be provided.

[0013] According to various embodiments of the present disclosure, a method and apparatus for supporting a continuous roaming operation within a BSS group without a separate association procedure in a wireless LAN system may be provided.

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

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

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

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

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

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

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

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

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

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

[0024] Fig. 9 is a flowchart for explaining the operation of the first STA according to an embodiment of the present disclosure.

[0025] Fig.10 is a diagram for explaining an operation of a first AP according to an embodiment of the present disclosure.

[0026] Fig.11 is a diagram for explaining a TB PPDU transmission and reception procedure between a transmitting STA and a receiving STA according to an example of the present disclosure. DETAILED DESCRIPTION

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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".

[0032] 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.

[0033] Hereinafter, technical features of examples to which the present disclosure can be applied will be described.

[0034] Figure 1 A block diagram of a wireless communication device according to an embodiment of the present disclosure is illustrated.

[0035] 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.

[0036] Figure 1 The devices 100 and 200 illustrated in the example may be referred to as stations (STAs). Figure 1 The devices 100 and 200 illustrated in the figure may be referred to by various terms such as a transmitting device, a receiving device, a transmitting STA, and a receiving STA. For example, STA110 and 200 may perform an access point (AP) role or a non-AP role. That is, in the present disclosure, STA110 and 200 may perform the functions of an AP and / or a non-AP. When STA110 and 200 perform an AP function, they may be simply referred to as an AP, and when STA110 and 200 perform a non-AP function, they may be simply referred to as a STA. In addition, in the present disclosure, an AP may also be indicated as an APSTA.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] 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.

[0045] For example, one of the STAs 100 and 200 may perform the expected operation of an AP, and the other of the STAs 100 and 200 may perform the expected operation of a non-AP STA. Figure 1 The transceivers 106 and 206 of the present invention may perform transmission and reception operations of signals (e.g., packets or physical layer protocol data units (PPDUs) compliant with IEEE 802.11a / b / g / n / ac / ax / be / bn). In addition, in the present disclosure, operations of various STAs generating transmission / reception signals or performing data processing or calculations on transmission / reception signals in advance may be performed by Figure 1The processors 102 and 202 are executed. For example, examples of operations of generating a transmission / reception signal or performing data processing or calculation for the transmission / reception signal in advance may include: 1) determining / obtaining / configuring / calculating / decoding / encoding bit information of fields (signal (SIG), short training field (STF), long training field (LTF), data, etc.) included in the PPDU; 2) determining / configuring / obtaining time resources or frequency resources (e.g., subcarrier resources) for fields (SIG, STF, LTF, data, etc.) included in the PPDU; 3) determining / configuring / obtaining a specific sequence (e.g., pilot sequence, STF / LTF sequence, additional sequence applied to SIG) for fields (SIG, STF, LTF, data, etc.) included in the PPDU action; 4) power control operations and / or power saving operations applied to STAs; 5) operations related to ACK signal determination / obtaining / configuring / calculating / decoding / encoding, etc. In addition, in the following example, various information used by various STAs to determine / acquire / configure / calculate / decode / encode transmission signals and reception signals (e.g., information related to fields / subfields / control fields / parameters / power, etc.) may be stored in Figure 1 in the memories 104 and 204.

[0046] Hereinafter, downlink (DL) may mean a link for communication from an AP STA to a non-AP STA, and a DL PPDU / packet / signal may be transmitted and received through the DL. In DL communication, a transmitter may be a part of an AP STA, and a receiver may be a part of a non-AP STA. An uplink (UL) may mean a link for communication from a non-AP STA to an AP STA, and an UL PPDU / packet / signal may be transmitted and received through the UL. In UL communication, a transmitter may be a part of a non-AP STA, and a receiver may be a part of an AP STA.

[0047] Figure 2 is a diagram illustrating an exemplary structure of a wireless LAN system to which the present disclosure can be applied.

[0048] 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.

[0049] 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.

[0050] 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).

[0051] 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.

[0052] 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.

[0053] 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).

[0054] 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.

[0055] 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.

[0056] In addition to the above-mentioned structure of the DS, an extended service set (ESS) may also be configured to provide wide coverage.

[0057] 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.

[0058] 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.

[0059] Figure 3 is a diagram for explaining a link establishment process to which the present disclosure can be applied.

[0060] 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.

[0061] 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.

[0062] 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).

[0063] 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.

[0064] 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.

[0065] 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.

[0066] 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.

[0067] 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.

[0068] 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.

[0069] 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 additional information may also be included.

[0070] 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.

[0071] 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.

[0072] Figure 4 It is a diagram for explaining a backoff process to which the present disclosure can be applied.

[0073] 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.

[0074] 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).

[0075] Reference Figure 4, the operation based on the random backoff period will be described. When the occupied / busy medium becomes idle, multiple STAs may attempt to send data (or frames). As a method of minimizing conflicts, each of the STAs may select a random backoff count respectively and attempt to send after waiting for the corresponding time slot time. The random backoff count has a pseudo-random integer value and may be determined as one of the values ​​ranging from 0 to CW. Here, CW is the contention window parameter value. The CW parameter is assigned CWmin as an initial value, but may take a value twice as large in the event of a transmission failure (e.g., when an ACK for the transmitted frame is not received). When the CW parameter value reaches CWmax, data transmission may 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 2n-1 (n=0, 1, 2, ...).

[0076] 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.

[0077] exist Figure 4 In the example of , when the packet to be sent arrives at the MAC of STA3, STA3 can send the frame immediately after confirming that the medium has been idle for up to DIFS. The remaining STAs monitor and wait for the medium to be occupied / busy. At the same time, the data to be sent can also occur in each of STA1, STA2 and STA5, and when the medium is monitored as idle, each STA waits for up to DIFS, and then the countdown of the backoff slot can be performed according to the random backoff count value selected by each STA. Assume that STA2 selects the minimum backoff count value and STA1 selects the maximum backoff count value. That is, the example illustrates a case where the remaining backoff time of STA5 is shorter than the remaining backoff time of STA1 when STA2 completes the backoff count and starts frame transmission. STA1 and STA5 temporarily stop the countdown and wait when STA2 occupies the medium. When STA2's occupancy ends and the medium becomes idle again, STA1 and STA5 wait for DIFS and restart the stopped backoff count. That is, frame transmission can start after counting down the remaining backoff slot for the remaining backoff time. Since the remaining backoff time of STA5 is shorter than that of STA1, STA5 starts frame transmission. The data to be transmitted may also occur in STA4 while STA2 occupies the medium. From the perspective of STA4, when the medium becomes idle, STA4 may wait for DIFS, and then may perform a countdown according to a random backoff count value selected by STA4, and start transmitting frames. Figure 4The example shows a case where the remaining backoff time of STA5 accidentally collides with the random backoff count value of STA4. In this case, a collision may occur between STA4 and STA5. When a collision occurs, neither STA4 nor STA5 receives an ACK, so data transmission fails. In this case, STA4 and STA5 can double the CW value, select a random backoff count value, and perform a countdown. While the medium is occupied due to the transmission of STA4 and STA5, STA1 waits, and when the medium becomes idle, STA1 waits DIFS, and then starts frame transmission after the remaining backoff time has passed.

[0078] As in Figure 4 In the example of , a data frame is a frame for sending data forwarded to a higher layer, and may be sent after a backoff performed after DIFS has passed since the medium became idle. In addition, a management frame is a frame for exchanging management information that is not forwarded to a higher layer, and is sent after a backoff is performed after an IFS such as DIFS or a point coordination function IFS (PIFS). As subtype frames of the management frame, there are beacons, association requests / responses, reassociation requests / responses, probe requests / responses, authentication requests / responses, and the like. A control frame is a frame for controlling access to a medium. As subtype frames of the control frame, there are request to send (RTS), clear to send (CTS), acknowledgement (ACK), power save poll (PS-Poll), block ACK (BlockAck), block ACK request (BlockACKReq), empty data packet announcement (NDP announcement), and trigger, and the like. If the control frame is not a response frame of the previous frame, it is sent after performing a backoff 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) has passed. The type and subtype of the frame can be identified by the type field and subtype field in the frame control (FC) field.

[0079] 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.

[0080] Figure 5 is a diagram for explaining a frame transmission operation based on CSMA / CA to which the present disclosure can be applied.

[0081] 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.

[0082] 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.

[0083] 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.

[0084] 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.

[0085] 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.

[0086] 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.

[0087] 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.

[0088] 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.

[0089] 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.

[0090] In this manner, information transmission / reception in the wireless LAN system is performed in the form of a frame, and for this purpose, a PHY layer protocol data unit (PPDU) format is defined.

[0091] The basic PPDU may include a short training field (STF), a long training field (LTF), a signal (SIG) field, and a data (Data) field. The most basic PPDU format (e.g., Figure 7 The non-HT (high throughput) shown in the figure may consist of only the legacy-STF (L-STF), the legacy-LTF (L-LTF), the legacy-SIG (L-SIG) field and the data field. In addition, depending on the type of PPDU format (e.g., HT mixed format PPDU, HT greenfield format PPDU, VHT (very high throughput) PPDU, etc.), additional (or different types of) RL-SIG, U-SIG, non-legacy SIG field, non-legacy STF, non-legacy LTF (i.e., xx-SIG, xx-STF, xx-LTF (e.g., xx is HT, VHT, HE, EHT, etc.)) and the like may be included between the L-SIG field and the data field.

[0092] 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.

[0093] The SIG field may include various information related to the transmission and reception of the PPDU. For example, the L-SIG field consists of 24 bits, and the L-SIG field may include a 4-bit rate field, a 1-bit reserved bit, a 12-bit length field, a 1-bit parity field, and a 6-bit tail field. The RATE field may include information about the modulation and coding rate of the data. For example, the 12-bit length field may include information about the length or duration of the PPDU. For example, the value of the 12-bit length field may be determined based on the type of the PPDU. For example, for non-HT, HT, VHT, or EHT PPDUs, the value of the length field may be determined as a multiple of 3. For example, for HEPPDUs, the value of the length field may be determined as a multiple of 3+1 or a multiple of 3+2.

[0094] 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.

[0095] MAC PDU is defined according to various MAC frame formats, and a basic MAC frame consists of a MAC header, a frame body, and a frame check sequence (FCS). A MAC frame may consist of a MAC PDU and be transmitted / received through a PSDU of a data portion of a PPDU format.

[0096] 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.

[0097] The null data PPDU (NDP) format refers to a PPDU format that does not include a data field. In other words, NDP refers to a frame format that includes a PPDU preamble (i.e., L-STF, L-LTF, L-SIG fields and additional non-legacy SIG, non-legacy STF, non-legacy LTF (if present)) of a general PPDU format and does not include the remaining part (i.e., the data field).

[0098] 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.

[0099] In standards such as IEEE 802.11a / g / n / ac / ax, various types of PPDUs have been used. The basic PPDU format (IEEE 802.11a / g) includes L-LTF, L-STF, L-SIG, and data fields. The basic PPDU format may also be referred to as a non-HT PPDU format (such as Figure 7 (as shown in (a)).

[0100] Compared to the basic PPDU format, the HT PPDU format (IEEE 802.11n) additionally includes HT-SIG, HT-STF, and HT-LFT fields. Figure 7The HT PPDU format shown in (b) may be referred to as an HT mixed format. In addition, an HT greenfield format PPDU may be defined, and this corresponds to a format consisting of HT-GF-STF, HT-LTF1, HT-SIG, one or more HT-LTFs, and a data field, excluding L-STF, L-LTF, and L-SIG (not shown).

[0101] Compared to the basic PPDU format, an example of the VHT PPDU format (IEEE 802.11ac) additionally includes VHTSIG-A, VHT-STF, VHT-LTF, and VHT-SIG-B fields (eg, Figure 7 (as shown in (c)).

[0102] Compared to the basic PPDU format, an example of the HE PPDU format (IEEE 802.11ax) additionally includes a repeated L-SIG (RL-SIG), HE-SIG-A, HE-SIG-B, HE-STF, HE-LTF, a packet extension (PE) field (such as Figure 7 (d) of the HE PPDU format). Some fields may be excluded or their lengths may vary according to the detailed example of the HE PPDU format. For example, the HE-SIG-B field is included in the HE PPDU format for multi-user (MU), and the HE-SIG-B is not included in the HE PPDU format for single user (SU). In addition, the HE trigger-based (TB) PPDU format does not include the HE-SIG-B, and the length of the HE-STF field may vary to 8μs. The extended range (HE ER) SU PPDU format does not include the HE-SIG-B field, and the length of the HE-SIG-A field may vary to 16μs. For example, the RL-SIG may be configured to be the same as the L-SIG. Based on the presence of the RL-SIG, the receiving STA may know that the received PPDU is a HE PPDU or an EHT PPDU, which will be described later.

[0103] The EHT PPDU format may include Figure 7 (e) EHT MU (multi-user) and Figure 7 The EHTTB (trigger-based) PPDU in (f) of FIG. The EHT PPDU format is similar to the HE PPDU format in that it includes the RL-SIG following the L-SIG, but may include the U (Universal)-SIG, the EHT-SIG, the EHT-STF, and the EHT-LTF following the RL-SIG.

[0104] Figure 7The EHT MU PPDU in (e) corresponds to a PPDU carrying one or more data (or PSDU) for one or more users. That is, the EHT MU PPDU can be used for both SU transmission and MU transmission. For example, the EHT MU PPDU can correspond to a PPDU for one receiving STA or multiple receiving STAs.

[0105] Compared with EHT MU PPDU, Figure 7 The EHT TB PPDU in (f) omits the EHT-SIG. A STA that receives a trigger for ULMU transmission (eg, a trigger frame or a triggered response schedule (TRS)) may perform UL transmission based on the EHT TB PPDU format.

[0106] The L-STF, L-LTF, L-SIG, RL-SIG, U-SIG (Universal Signal), EHT-SIG fields may be coded and modulated so that even legacy STAs may attempt to demodulate and decode, and may be mapped based on a determined subcarrier frequency interval (e.g., 312.5kHz). These may be referred to as pre-EHT modulation fields. Next, the EHT-STF, EHT-LTF, data, PE fields may be coded and modulated so that they may be demodulated and decoded by a STA that successfully decodes a non-legacy SIG (e.g., U-SIG and / or EHT-SIG) and obtains the information included in the field, and may be mapped based on a determined subcarrier frequency interval (e.g., 78.125kHz). These may be referred to as EHT modulation fields.

[0107] Similarly, in the HE PPDU format, the L-STF, L-LTF, L-SIG, RL-SIG, HE-SIG-A, and HE-SIG-B fields may be referred to as pre-HE modulation fields, and the HE-STF, HE-LTF, data, and PE fields may be referred to as HE modulation fields. In addition, in the VHT PPDU format, the L-STF, L-LTF, L-SIG, and VHT-SIG-A fields may be referred to as non-VHT modulation fields, and the VHT STF, VHT-LTF, VHT-SIG-B, and data fields may be referred to as VHT modulation fields.

[0108] Included in Figure 7The U-SIG in the EHT PPDU format may be configured based on, for example, two symbols (e.g., two consecutive OFDM symbols). Each symbol (e.g., OFDM symbol) used for the U-SIG may have a duration of 4 μs, and the U-SIG may have a total duration of 8 μs. Each symbol of the U-SIG may be used to send 26 bits of information. For example, each symbol of the U-SIG may be sent and received based on 52 data tones and 4 pilot tones.

[0109] The U-SIG may be constructed in units of 20 MHz. For example, if an 80 MHz PPDU is constructed, the U-SIG may be duplicated. That is, the same 4 U-SIGs may be included in the 80 MHz PPDU. A PPDU with a bandwidth exceeding 80 MHz may include a different U-SIG.

[0110] For example, A uncoded bits may be sent via U-SIG, the first symbol of U-SIG (e.g., U-SIG-1 symbol) may send the first X bits of information out of a total of A bits of information, and the second symbol of U-SIG (e.g., U-SIG-2 symbol) may send the remaining Y bits of information out of a total of A bits of information. The A bits of information (e.g., 52 uncoded bits) may include a CRC field (e.g., a 4-bit long field) and a tail field (e.g., a 6-bit long field). For example, the tail field may be used to terminate the trellis structure of the convolutional decoder and may be set to 0.

[0111] The bit information sent through U-SIG can be divided into version-independent bits and version-dependent bits. For example, U-SIG can be included in Figure 7 In a new PPDU format not shown in the EHT PPDU format (e.g., UHR PPDU format), and may be included in the format of the U-SIG field included in the EHT PPDU format and the format of the U-SIG field included in the UHR PPDU format, the version-independent bits may be the same, and some or all of the version-related bits may be different.

[0112] For example, the size of the version-independent bit of the U-SIG may be fixed or variable. The version-independent bit may be assigned only to the U-SIG-1 symbol, or to both the U-SIG-1 symbol and the U-SIG-2 symbol. The version-independent bit and the version-dependent bit may be referred to by various names, such as a first control bit and a second control bit.

[0113] For example, the version-independent bits of the U-SIG may include a 3-bit physical layer version identifier (PHY version identifier), and this information may indicate the PHY version (e.g., EHT, UHR, etc.) of the transmitted / received PPDU. The version-independent bits of the U-SIG may include a 1-bit UL / DL flag field. The first value of the 1-bit UL / DL flag field is related to UL communication, and the second value of the UL / DL flag field is related to DL communication. The version-independent bits of the U-SIG may include information about the length of a transmit opportunity (TXOP) and information about a BSS color ID.

[0114] For example, the version-related bits of the U-SIG may include information directly or indirectly indicating the type of the PPDU (eg, SU PPDU, MU PPDU, TB PPDU, etc.).

[0115] Information required for PPDU transmission and reception may be included in the U-SIG. For example, the U-SIG may also include information about bandwidth, information about an MCS technology applied to a non-legacy SIG (e.g., EHT-SIG or UHR-SIG, etc.), information indicating whether a DCM (dual carrier modulation) technology (e.g., a technology for achieving an effect similar to frequency diversity by reusing the same signal on two subcarriers) is applied to the non-legacy SIG, information about the number of symbols used for the non-legacy SIG, and information about whether the non-legacy SIG is generated across the entire frequency band.

[0116] Some of the information required for PPDU transmission and reception may be included in the U-SIG and / or the non-legacy SIG (e.g., EHT-SIG or UHR-SIG, etc.). For example, information about the type of non-legacy LTF / STF (e.g., EHT-LTF / EHT-STF or UHR-LTF / UHR-STF, etc.), information about the length of the non-legacy LTF and the CP (cyclic prefix) length, information about the GI (guard interval) applicable to the non-legacy LTF, information about preamble puncturing applicable to the PPDU, information about resource unit (RU) allocation, etc. may be included only in the U-SIG, only in the non-legacy SIG, or may be indicated by a combination of information included in the U-SIG and information included in the non-legacy SIG.

[0117] Preamble puncturing may indicate the transmission of a PPDU in which there is no signal in one or more frequency units in the bandwidth of the PPDU. For example, the size of the frequency unit (or the resolution of the preamble puncturing) may be defined as 20 MHz, 40 MHz, etc. For example, preamble puncturing may be applied to a PPDU bandwidth of a predetermined size or greater.

[0118] exist Figure 7In the example of , non-legacy SIGs such as HE-SIG-B and EHT-SIG may include control information for receiving STAs. The non-legacy SIG may be transmitted on at least one symbol, and one symbol may have a length of 4 μs. Information about the number of symbols used for the EHT-SIG may be included in a previous SIG (eg, HE-SIG-A, U-SIG, etc.).

[0119] Non-legacy SIGs such as HE-SIG-B and EHT-SIG may include a common field and a user-specific field. The common field and the user-specific field may be encoded separately.

[0120] In some cases, the common field may be omitted. For example, in a compressed mode that does not apply OFDMA (Orthogonal Frequency Division Multiple Access), the common field may be omitted, and multiple STAs may receive the PPDU (e.g., the data field of the PPDU) through the same frequency band. In a non-compressed mode that applies OFDMA, multiple users may receive the PPDU (e.g., the data field of the PPDU) through different frequency bands.

[0121] The number of user-specific fields may be determined based on the number of users. A user block field may include up to two user fields. Each user field may be associated with a MU-MIMO allocation or may be associated with a non-MU-MIMO allocation.

[0122] The common field may include a CRC bit and a tail bit, and the length of the CRC bit may be determined to be 4 bits, and the length of the tail bit may be determined to be 6 bits and set to 000000. The common field may include RU allocation information. The RU allocation information may include information about the positions of RUs to which multiple users (ie, multiple receiving STAs) are assigned.

[0123] RU can include multiple subcarriers (or tones). RU can be used when sending signals to multiple STAs based on OFDMA technology. In addition, RU can be defined even when sending signals to one STA. Resources can be allocated to non-traditional STF, non-traditional LTF and data fields in units of RU.

[0124] The RU of applicable size may be defined according to the PPDU bandwidth. The RU may be defined identically or differently for the applied PPDU format (e.g., HEPPDU, EHT PPDU, UHR PPDU, etc.). For example, in the case of an 80MHz PPDU, the RU layout of the HEPPDU and EHT PPDU may be different. The applicable RU size, the number of RUs and RU positions, the DC (direct current) subcarrier positions and numbers, the empty subcarrier positions and numbers, the guard subcarrier positions and numbers, etc. for each PPDU bandwidth may be referred to as a tone plan. For example, a tone plan for high bandwidth may be defined in the form of multiple iterations of a low bandwidth tone plan.

[0125] RUs of various sizes may be defined as 26-tone RUs, 52-tone RUs, 106-tone RUs, 242-tone RUs, 484-tone RUs, 996-tone RUs, 2×996-tone RUs, 3×996-tone RUs, etc. MRUs (multi-RUs) are different from multiple individual RUs and correspond to a group of subcarriers consisting of multiple RUs. For example, one MRU may be defined as 52+26 tones, 106+26 tones, 484+242 tones, 996+484 tones, 996+484+242 tones, 2×996+484 tones, 3×996 tones, or 3×996+484 tones. In addition, the multiple RUs constituting one MRU may or may not be continuous in the frequency domain.

[0126] The specific size of the RU may be reduced or expanded. Therefore, the specific size of each RU in the present disclosure (i.e., the number of corresponding tones) is not restrictive but illustrative. In addition, in the present disclosure, within a predetermined bandwidth (e.g., 20 MHz, 40 MHz, 80 MHz, 160 MHz, 320 MHz ...), the number of RUs may vary according to the RU size.

[0127] Figure 7 The names of each field in the PPDU format are exemplary, and the scope of the present disclosure is not limited by these names. In addition, the examples of the present disclosure can be applied to Figure 7 The PPDU format shown in Figure 7 A new PPDU format that excludes some fields and / or adds some fields.

[0128] Multiple BSSID Process

[0129] A single beacon frame may include elements for multiple BSSID set members. Only the AP corresponding to the transmitting BSSID may transmit a beacon frame. If the beacon and probe response frames include corresponding BSSID information, the AP corresponding to the transmitting BSSID may search for non-transmitting BSSIDs. However, the AP may not perform the above operations on all frames.

[0130] The AP that sends the EHT NDP announcement frame identifying the EHT STA can set the TA field of the frame to the MAC address of the AP. In addition, the EHT NDP announcement frame can identify STAs in at least two different BSSs among the multiple BSSID sets. In this case, the AP can set the TA field of the frame to the sending BSSID.

[0131] When the EHT NDP announcement frame is transmitted in a non-HT repetition PPDU, the TA field of the EHT NDP announcement frame may be a bandwidth signal TA.

[0132] HE BSSs that are not part of a multi-BSSID set but share the same operating category, channel, receive antenna connector, and transmit antenna connector may belong to a co-hosted BSSID set. All APs that are members of a multi-BSSID set or a co-hosted BSSID set may use the same BSS color.

[0133] Multiple Access Point (MAP) Operation

[0134] Hereinafter, examples of the present disclosure for multiple access point (MAP) operations are described.

[0135] 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).

[0136] 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.

[0137] 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.

[0138] A STA in MAP operation may associate with a slave AP or a master AP to configure a BSS.

[0139] 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.

[0140] 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.

[0141] Figure 8 It is a diagram for explaining various transmission and reception techniques in a MAP environment to which the present disclosure can be applied.

[0142] 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 neighbors. Figure 8 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.

[0143] In MAP technology, performance can be improved by reducing inter-symbol interference (ISI) through cooperation between neighbors or by performing joint transmission. Figure 8 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.

[0144] Figure 8 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.

[0145] Figure 8 (d) shows an AP selection method in which an AP having a good channel condition among neighbors performs transmission.

[0146] Can be applied as Figure 8As in the example of (e), multiple APs cooperate to simultaneously transmit or receive joint transmission (JTX) or joint reception (JRX), and further, joint MU-MIMO can be supported.

[0147] BSS Group

[0148] When describing the present disclosure, a BSS group may be described as a virtual BSS or a seamless roaming (SR) BSS. A BSS group may refer to a BSS infrastructure with a set of coordinated APs. A coordinated AP group may include a multi-AP coordinator and one or more member APs. An anchor AP may refer to an AP selected to serve a STA.

[0149] All member APs within a BSS group may share the same SSID and share association / authentication. In addition, all member APs within a BSS group may have the same BSSID, but are not limited thereto.

[0150] When a (non-AP) STA roams within a BSS group, no additional association / authentication may be required. A STA may use the same AID within a BSS group and may have a local copy with the capabilities of the anchor AP and neighbors.

[0151] In addition, a STA can receive or send packets from any AP within the BSS group. A STA can process all data packets based on the anchor AP as if they were sent to or received from a single AP.

[0152] In the past, in order to move from a specific BSS to a neighbor BSS, the STA disconnected from the specific BSS and then performed an association process with the neighbor BSS. That is, there was a problem that the STA had to repeat the connection termination and association process every time it performed the BSS movement process.

[0153] Hereinafter, methods for configuring BSS groups and procedures within the BSS group are described to ensure that there is no separate joining process or data transmission interruption when moving the BSS.

[0154] Fig. 9 is a flowchart for explaining the operation of the first STA according to one embodiment of the present disclosure. Fig. 9 and Fig.10 In the embodiment, the first STA is a non-AP STA, and the first AP and the second AP may be shared APs (Shared APs) included in the same BSS group. The first AP and the second AP may share a specific BSSID (i.e., a public BSSID) associated with the BSS group. In addition, the representative AP may refer to a shared AP (Sharing AP).

[0155] The first STA may receive a beacon frame including a specific BSSID from a first access point (AP) included in a BSS (Basic Service Set) group ( S910 ).

[0156] For example, a beacon frame may be sent to the first STA based on a unique BSSID of the first AP. The first STA may obtain a specific BSSID based on the beacon frame. Here, the specific BSSID may be a public BSSID used for data transmission and reception with at least one AP.

[0157] Here, the first STA may have a capability associated with the BSS group. And, the unique BSSID may be, but is not limited to, one of the transmission BSSIDs included in the multi-BSSID set.

[0158] The first STA may perform association with a BSS group based on a specific BSSID ( S920 ).

[0159] That is, the first STA can perform seamless data transmission and reception with at least one AP in the BSS group by associating with the BSS group via a specific BSSID. For example, the first STA can receive a second PPDU from a second AP among at least one AP based on the specific BSSID without an association process.

[0160] The first STA may receive a first PPDU (Physical Layer Protocol Data Unit) from at least one AP included in the BSS group ( S930 ).

[0161] For example, the first STA may simultaneously receive the first PPDU from at least one AP included in the BSS group. A trigger frame including a transmission area and a transmission method of the first PPDU may be sent from the representative AP to at least one AP. The DA or RA of the trigger frame may be set to a specific BSSID, and at least one AP may send the first PPDU to the first STA based on the trigger frame.

[0162] The first STA may transmit response information for the first PPDU to the at least one AP. An RA (reception address) field or a DA (destination address) field of the first frame including the response information may be set to a specific BSSID.

[0163] For example, the response information may include information on the reception status of the first PPDU and channel information. The channel information may include at least one of a received signal strength indicator (RSSI) or a signal to interference plus noise ratio (SINR).

[0164] And, the first frame may be at least one of an ACK (Acknowledgement) frame or a BA (Block ACK) frame. And, at least one of the ACK frame or the BA frame may include a HT (High Throughput) control field including channel information.

[0165] Based on the transmission area and transmission method included in the trigger frame, response information can be sent from at least one AP to the representative AP via the second frame. The SA (source address) or TA (transmission address) of the second frame can be set to a unique BSSID of each AP in the at least one AP.

[0166] exist Fig. 9 The method performed by the first STA described in the example of Figure 1 The first device (100) performs. For example, Figure 1 One or more processors (102) of a first device (100) may be configured to receive a beacon frame including a specific BSSID from a first access point (AP) included in a BSS group through one or more transceivers (106). The one or more processors (102) may perform association for the BSS group based on the specific BSSID. The one or more processors (102) may receive a first PPDU from at least one AP included in the BSS group through the one or more transceivers (106).

[0167] In addition, one or more memories (104) of the first device (100) may store instructions for executing when executed by one or more processors (102). Fig. 9 Instructions for the methods described in the examples.

[0168] Fig.10 is a diagram for describing the operation of a first AP according to one embodiment of the present disclosure.

[0169] The first AP may receive a trigger frame including a transmission region and a transmission method of a first PPDU from a representative AP ( S1010 ).

[0170] For example, the transmission region of the first PPDU may include information about at least one resource region used to transmit the first PPDU. In addition, the transmission method of the first PPDU may include at least one of a coding type, a modulation and coding scheme (MCS), and a number of streams related to the transmission of the first PPDU.

[0171] Here, the SA (source address) or TA (transmission address) of the first trigger frame may be set to a specific BSSID associated with the BSS group including the first AP.

[0172] The first AP may send a first PPDU to the first STA based on the trigger frame ( S1020 ).

[0173] That is, the first AP may transmit the first PPDU to the first STA based on the at least one resource region indicated by the trigger frame, the coding type, the MCS, and the number of streams associated with the first PPDU transmission.

[0174] The first AP may send response information for the first PPDU to the representative AP (S1030). Accordingly, the representative AP may determine a channel state between the first AP and the first STA.

[0175] Furthermore, a second PPDU may be sent to the first STA from a second AP among a plurality of APs including the first AP based on a specific BSSID without an association process. Here, the plurality of APs including the first AP may refer to shared APs included in the same BSS group. That is, the plurality of APs may include the first AP, the second AP, and the like. That is, the second AP may send a second PPDU to the first STA based on a specific BSSID without a separate association process.

[0176] exist Fig.10 The method performed by the first AP described in the example may be performed by Figure 1 The second device (200) is executed. For example, Figure 1 One or more processors (202) of the second device (200) may receive a trigger frame including a transmission area and a transmission method of a first PPDU from a representative AP through one or more transceivers (206). The one or more processors (202) may transmit the first PPDU to the first STA through the one or more transceivers (206) based on the trigger frame. The one or more processors (202) may receive response information (206) for the first PPDU from the first STA through the one or more transceivers. The one or more processors (202) may transmit the response information for the first PPDU to the representative AP through the one or more transceivers (206).

[0177] In addition, the one or more memories (204) of the second device (200) may store instructions for executing when executed by the one or more processors (202). Fig.10 Instructions for the methods described in the examples.

[0178] Hereinafter, a method of forming a group of one or more APs (or / and BSSs) and a MAP operation within the group are described in detail.

[0179] Implementation Method 1

[0180] A BSS group (i.e., a virtual (V)-BSS or SR-BSS) may include one or more BSSs. A STA that transmits and receives data with an AP included in the BSS group may perform continuous roaming between APs without separate association with each AP (or through a simple (re)association process).

[0181] Here, one or more BSSs may be configured as a BSS group within an ESS with the same SSID. The BSS group may be configured differently for each STA, and multiple BSS groups may exist within the same ESS. In addition, the same BSS may operate overlappingly within multiple BSS groups.

[0182] The representative AP may schedule the selection of APs for operation within the BSS group (ie, V-BSS or SR-BSS operation) and communication with STAs. Here, the representative AP may also be expressed as a shared AP, a master AP, an AP coordinator, a multi-AP coordinator, etc.

[0183] Each AP within a BSS group may have multiple BSSIDs, and all APs may commonly use one BSSID among the multiple BSSIDs to send and receive BSS group data.

[0184] For example, when an AP has multiple BSSID sets, each AP within the BSS group can have a unique transmit BSSID, and beacon frames can be sent based on the unique transmit BSSID. In addition, the APs within the BSS group can have a common non-transmit BSSID. In this case, the non-transmit BSSID can be used to send and receive data within the BSS group.

[0185] As another example, MAC addresses or BSSIDs of APs included in the same BSS group may be set to a common value, and the STA may regard these APs as one AP.

[0186] Hereinafter, a unique BSSID of each AP is referred to as a unique BSSID, and a BSSID commonly used for data transmission and reception within a BSS group (ie, V-BSS / SR-BSS data transmission and reception) is referred to as a common BSSID.

[0187] Here, AP may refer to a single physical AP, but may also refer to a co-located AP. In addition, a different AP may be set for each BSSID. For example, one of the physically co-located APs may have a common BSSID and the other may have a unique BSSID.

[0188] Alternatively, when a multi-link device (MLD) or a multi-BSSID set is applied to the BSSID related operation, the BSSID may be set according to the method described below.

[0189] In the first method, one of the MLD links can be set to the BSSID for the BSS group, and the dual connectivity operation described below is possible. Specifically, in the 2.4 / 5 / 6GHz band with wide coverage, seamless roaming between APs can be supported by setting it to the BSSID for the BSS group, and in the 5 / 6 / 60GHz band with heavy transmission, operations based on the AP's own BSSID can be supported.

[0190] Alternatively, one link may be designated for a BSS group, and the link may be used only for data transmission without sending management frames (eg, beacon frames), thereby supporting seamless data roaming.

[0191] In the second method, one of the transmission BSSIDs included in the multi-BSSID set can be set as the BSSID for the BSS group, and the dual connection operation described below can be supported. For example, the transmission BSSID can be used for management frames (e.g., beacon frames, etc.) and communications in the BSS of one AP. The non-transmission BSSID can be used to support seamless roaming between APs.

[0192] Within a BSS group, an association operation may be performed using a common BSSID or a unique BSSID. Data transmission and reception may be performed using another BSSID within the BSS group without a separate (re) association operation (or by a simplified (re) association operation). The above operation may be applied to both the first method and the second method.

[0193] That is, in a basic wireless LAN system, when operating multiple links, an association operation must be performed individually for each link. However, when operating a BSS group, if an association operation is performed based on one BSSID, separate association operations may not be required for other links.

[0194] Implementation Method 1-1

[0195] Implementation 1-1 relates to the data sending and receiving process within a BSS group.

[0196] A non-AP STA with BSS group-related capabilities within the BSS group can receive a beacon frame sent using a unique BSSID. The non-AP STA can obtain the public BSSID information (e.g., public BSSID, public capabilities, etc.) of the BSS group through the beacon frame and perform association based on the public BSSID, thereby publicly associating with the BSS group.

[0197] As another example, a non-AP STA may perform association via a unique BSSID and then report association related information to a shared AP. Thus, a shared AP may perform association with other APs / non-APs via a public BSSID or share associated STA information with an AP.

[0198] For example, a common BSSID can be used for data transmission and reception within a BSS group. When a non-AP STA transmits and receives data with multiple APs within a BSS group, it can operate as if it is transmitting and receiving data with a single AP without a separate association process (or only using a simple association process) (e.g., information sharing between APs).

[0199] As an example of the present disclosure, the AP operating in the BSS group must follow the instructions of the shared AP when sending data, and can report information about data reception from non-AP STAs to the shared AP. That is, data transmission and reception within the BSS group can be performed according to the process described below.

[0200] 1. Send a shared AP indication message

[0201] The shared AP may determine an AP (i.e., a shared AP) that transmits and receives data within the BSS group. The shared AP may then send an indication message including an ID of the determined AP (e.g., a BSSID of a corresponding AP for distinguishing the corresponding AP), a transmission area (e.g., resource allocation information), and a transmission method (e.g., coding type, MCS, number of streams, etc.) to the determined AP. The transmission area and the method for transmitting and receiving data may be common information to the shared AP.

[0202] Additionally or alternatively, the indication message sent by the shared AP may include the transmit power of the shared AP.

[0203] Here, the shared AP may send the above-mentioned indication message to the AP via a trigger frame. For example, the destination address (DA) or receiving address (RA) of the indication message may be set to a public BSSID or a broadcast ID. That is, the DA or RA of the trigger frame including the indication message may be set to a public BSSID or a broadcast ID.

[0204] 2. Data transmission while being shared by AP

[0205] The method of data transmission within the BSS group may include a method in which shared APs simultaneously transmit the same data in the same area using the same method, which is different from other multi-AP operations such as C-TX (coordinated transmission) or J-TX (joint transmission).

[0206] Here, the TA (transmission address) or SA (source address) of the data frame transmitted within the BSS group may be set to a common BSSID within the BSS group. And, the shared AP may simultaneously transmit the corresponding data frames in the same PPDU format.

[0207] In the basic wireless LAN system, the format of the frame sent after the trigger format is UL TB PPDU. However, within the BSS group, instead of UL, SU (Single User) or MU (Multi-User) DL messages (e.g., DL MU OFDMA format of the IEEE 802.11be standard) sent by the shared AP to the non-AP STA can be sent and received.

[0208] 3. The non-AP STA that receives the data sends an ACK message

[0209] Assume that the shared AP sends data (simultaneously). The non-AP STA receiving data from the shared AP cannot know which shared AP in the BSS group sent the data. Therefore, the non-AP STA can send a response message for the received data by setting the DA (destination address) or RA (receiving address) to the public BSSID, which is the TA (transmitting address) or SA (source address) of the received data.

[0210] Here, the response message may include channel information and information about a reception status (eg, ACK / NACK information). For example, the response message may be included in an ACK frame or a BA frame defined in the IEEE 802.11 standard, and the frame may include HT control including channel information.

[0211] Alternatively, an MPDU including information such as RSSI (Received Signal Strength Indicator) or SINR (Signal to Interference plus Noise Ratio) may be incorporated into the frame and transmitted to the shared AP.

[0212] 4. The shared AP reports the received ACK message to the sharing AP.

[0213] The shared AP may report a response message (eg, an ACK message, etc.) received from the non-AP STA to the shared AP.

[0214] As an example of the present disclosure, the shared AP may set the SA or TA of the report message reported to the sharing AP to a unique BSSID. Therefore, the shared APs may each send a report message to the sharing AP.

[0215] Here, the indication message (i.e., the trigger frame including the indication message) transmitted by the shared AP described in process 1 may respectively indicate the transmission area (e.g., resource allocation, etc.) and data transmission method (e.g., coding type, MCS, number of streams, etc.) of each shared AP. Each shared AP may report link quality information (e.g., received power, RSSI, SINR, etc.) of the response message received from the non-AP STA to the shared AP. Therefore, the shared AP may recognize the channel status between the non-AP STA and each shared AP.

[0216] As another example of the present disclosure, the shared AP may directly forward the response message received from the non-AP STA to the shared AP, but may change the DA or RA of the response message to information related to the shared AP (e.g., the ID of the shared AP, etc.). As another example, the shared AP may encapsulate a response message in which the SA or TA is set to a common BSSID in the BSS group and the DA or RA is set to the BSSID of the shared AP, and report it to the shared AP.

[0217] Uplink data transmission and reception within the BSS group may be performed based on UL TB PPDU transmission and reception through a trigger frame, or based on UL SU PPDU after acquiring a TXOP (transmission opportunity).

[0218] For example, when uplink data transmission / reception based on ULTB PPDU through a trigger frame is performed within the BSS group, the sending of the indication message of the shared AP described in process 1 can be performed before sending the trigger frame of the shared AP. In addition, after receiving the uplink data, the shared AP can transmit the data to the shared AP as in process 4.

[0219] Implementation Method 2

[0220] Embodiment 2 relates to a method for setting a set of shared APs capable of transmitting and receiving data with each non-AP STA within a BSS group.

[0221] A non-AP STA may accidentally hear a beacon message that can be heard within the BSS group. The non-AP STA may report the accidentally heard channel information (e.g., received power, RSSI, SINR, etc.) to each shared AP based on a unique BSSID, and each shared AP may report the reported information to the shared AP.

[0222] The shared AP may determine the shared AP to transmit and receive with the non-AP STA based on the information reported by the shared AP. The reported information may be updated by periodic indication from the shared AP or by self-reporting from the non-AP STA.

[0223] The above report information may also be updated through the link quality information of the ACK message in process 4 of implementation mode 1-1. Additionally or alternatively, the update of the above report information may be performed based on the NDP detection process.

[0224] Fig.11 is a diagram for explaining a PPDU transmission and reception process between a transmitting STA and a receiving STA according to one embodiment of the present disclosure. Fig.11 Some steps shown in . The transmitting device and the receiving STA can be an AP and / or a non-AP STA.

[0225] The transmitting STA may obtain control information related to the above tone plan (or RU) (S105). The control information related to the tone plan may include the size and location of the RU, control information related to the RU, information about the frequency band including the RU, information about the STA receiving the RU, etc.

[0226] The transmitting STA may configure / generate a PPDU based on the acquired control information (S110). Configuring / generating a PPDU may mean configuring / generating each field of the PPDU. That is, the step of configuring / generating a PPDU may include a step of configuring an EHT-SIG-A / B / C field including control information about a tone plan.

[0227] That is, the step of configuring / generating the PPDU may include the step of configuring a field including control information (e.g., N bitmap) indicating the size / location of the RU and / or the step of configuring a field including an identifier (e.g., AID) of the STA receiving the RU.

[0228] In addition, the step of configuring / generating the PPDU may include the step of generating an STF / LTF sequence to be transmitted via a specific RU. The STF / LTF sequence may be generated based on a preset STF generation sequence / LTF generation sequence.

[0229] In addition, the step of constructing / generating the PPDU may include the step of generating a data field (ie, MPDU) to be transmitted via a specific RU.

[0230] The transmitting STA may transmit the configured / generated PPDU to the receiving STA (S115).

[0231] Specifically, the transmitting STA may perform at least one of cyclic shift diversity (CSD), spatial mapping, inverse discrete Fourier transform (IDFT) / inverse fast Fourier transform (IFFT) operations, and guard interval (GI) insertion operations.

[0232] The receiving STA may decode the PPDU and obtain control information related to the tone plan (or RU) (S120).

[0233] Specifically, the receiving STA can decode the L-SIG and EHT-SIG of the PPDU based on the L-STF / LTF and obtain the information included in the L-SIG and EHT SIG fields. Information about various tone plans (ie, RU) of the present disclosure may be included in the EHT-SIG (eg, EHT-SIG-A / B / C), and the receiving STA may obtain information about the tone plan (ie, RU) through the EHT-SIG.

[0234] The receiving STA may decode the rest of the PPDU based on the information about the acquired tone plan (ie, RU) (S125). For example, the receiving STA may decode the STF / LTF field of the PPDU based on the information about the tone plan (ie, RU). In addition, the receiving STA may decode the data field of the PPDU based on the information about the tone plan (ie, RU) and obtain the MPDU included in the data field.

[0235] In addition, the receiving STA may perform a processing operation to transmit the decoded data to a higher layer (eg, MAC layer). In addition, if the generation of a signal is indicated from the higher layer to the PHY layer in response to the data transmitted to the higher layer, the receiving STA may perform subsequent operations.

[0236] 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.

[0237] 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.

[0238] 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.

[0239] Industrial Applicability

[0240] The method proposed in the present disclosure has been described focusing on an example of application to a system based on IEEE 802.11, but the method proposed in the present disclosure may be applied to various WLANs or wireless communication systems in addition to 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 beacon frame including a specific BSSID from a first access point AP included in a basic service set BSS group; performing association for the BSS group based on the specific BSSID; as well as receiving a first physical layer protocol data unit PPDU from at least one AP included in the BSS group, The specific BSSID is a public BSSID used to send and receive data with the at least one AP, and Wherein, without performing an association process, a second PPDU is received from a second AP among the at least one AP based on the specific BSSID.

2. The method according to claim 1, wherein: sending response information for the first PPDU to the at least one AP, and A reception address RA field or a destination address DA field of a first frame including the response information is set to the specific BSSID.

3. The method according to claim 2, wherein: The response information includes information about a reception status of the first PPDU and channel information, and The channel information includes at least one of a received signal strength indicator (RSSI) or a signal to interference plus noise ratio (SINR).

4. The method according to claim 2, wherein: The first frame is at least one of an acknowledgement ACK frame or a block ACK BA frame, and At least one of the ACK frame or the BA frame includes a high throughput HT control field including channel information.

5. The method according to claim 1, wherein: The first PPDU is sent from at least one AP to the first STA simultaneously.

6. The method according to claim 1, wherein: A trigger frame is sent from the representative AP to the at least one AP, the trigger frame including a transmission area and a transmission method of the first PPDU, and The DA or RA of the trigger frame is set to the specific BSSID.

7. The method according to claim 6, wherein: transmitting response information from the at least one AP to the representative AP through a second frame based on the transmission area and the transmission method included in the trigger frame, and A source address SA or a transmission address TA of the second frame is set to a unique BSSID of each of the at least one AP.

8. The method according to claim 1, wherein: The specific BSSID is one of the transmitting BSSIDs included in the multi-BSSID set.

9. The method according to claim 1, wherein: The first STA has a capability associated with the BSS group.

10. A first station STA operating in a wireless LAN system, the first STA comprising: at least one transceiver; as well as at least one processor coupled to the at least one transceiver, Wherein, the at least one processor is configured to: receiving, by the at least one transceiver, a beacon frame including a specific BSSID from a first access point AP included in a basic service set BSS group; performing association for the BSS group based on the specific BSSID; and receiving, through the at least one transceiver, a first physical layer protocol data unit (PPDU) from at least one AP included in the BSS group, The specific BSSID is a public BSSID used to send and receive data with the at least one AP, and Wherein, without performing an association process, a second PPDU is received from a second AP among the at least one AP based on the specific BSSID.

11. A method performed by a first access point (AP) in a wireless LAN system, the method comprising the following steps: receiving a trigger frame from a representative AP, the trigger frame including a transmission area and a transmission method of a first physical layer protocol data unit PPDU; Sending the first PPDU to the first STA based on the trigger frame; receiving, from the first STA, response information for the first PPDU; as well as sending response information for the first PPDU to the representative AP, The source address SA or the sending address TA of the first trigger frame is set to a specific BSSID related to the basic service set BSS group including the first AP, and Wherein, without performing an association process, a second PPDU is sent to the first STA from a second AP among a plurality of APs including the first AP based on the specific BSSID.

12. A first access point (AP) operating in a wireless LAN system, the first AP comprising: at least one transceiver; as well as at least one processor coupled to the at least one transceiver, Wherein, the at least one processor is configured to: receiving, by the at least one transceiver, a trigger frame from the representative AP, the trigger frame including a transmission area and a transmission method of a first physical layer protocol data unit PPDU; Sending the first PPDU to a first STA based on the trigger frame by the at least one transceiver; receiving, through the at least one transceiver, response information for the first PPDU from the first STA; and sending, through the at least one transceiver, response information for the first PPDU to the representative AP, The source address SA or the sending address TA of the first trigger frame is set to a specific BSSID related to the basic service set BSS group including the first AP, and Wherein, without performing an association process, a second PPDU is sent to the first STA from a second AP among a plurality of APs including the first AP based on the specific BSSID.

13. A processing device, the processing device being configured to control a first station (STA) operating 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 beacon frame including a specific BSSID from a first access point AP included in a basic service set BSS group; performing association for the BSS group based on the specific BSSID; and receiving a first physical layer protocol data unit PPDU from at least one AP included in the BSS group, The specific BSSID is a public BSSID used to send and receive data with the at least one AP, and Wherein, without performing an association process, a second PPDU is received from a second AP among the at least one AP based on the specific BSSID.

14. 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 beacon frame including a specific BSSID from a first access point AP included in a basic service set BSS group; performing association for the BSS group based on the specific BSSID; and receiving a first physical layer protocol data unit PPDU from at least one AP included in the BSS group, The specific BSSID is a public BSSID used to send and receive data with the at least one AP, and Wherein, without performing an association process, a second PPDU is received from a second AP among the at least one AP based on the specific BSSID.

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