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

Abstract

Disclosed are a method and an apparatus for scheduling based on multiple access point (AP) operation in a wireless LAN system. A method performed by a first type station (STA) in a wireless LAN system according to one embodiment of the present disclosure may comprise the steps of: receiving, from a second type STA, information related to one or more service periods (SP) for a first type STA among a plurality of first type STAs; and performing a frame exchange with one or more third type STAs associated with the first type STA based on the information related to the one or more SPs. The one or more SPs may include SPs that restrict STAs other than the first type STA and the one or more third type STAs to transmit. The information related to the one or more SPs further includes information about the other one or more SPs, the other one or more SPs allow one or more other first type STAs among the plurality of first type STAs or one or more third type STAs associated with the one or more other first type STAs among the one or more other third type STAs to transmit.

Description

Technical Field

[0001] The present disclosure relates to a scheduling method and apparatus based on multi - access point (AP) operation in a wireless local area network (WLAN) system. Background Art

[0002] New technologies for improving transmission rate, increasing bandwidth, improving reliability, reducing errors, and reducing latency have been introduced for wireless local area network (WLAN). Among WLAN technologies, the Institute of Electrical and Electronics Engineers (IEEE) 802.11 series of standards can be referred to as Wi - Fi. For example, recently introduced technologies to WLAN include very high throughput (VHT) enhancements of the 802.11ac standard and high efficiency (HE) enhancements of the IEEE 802.11ax standard.

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

[0004] Technical Problem

[0005] A technical problem of the present disclosure is to provide a scheduling method and apparatus based on multi - AP operation in a WLAN system.

[0006] An additional technical problem of the present disclosure is to provide a method and apparatus in a WLAN system, in which one AP participating in multi - AP operation schedules a service period (SP) of at least one other AP.

[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] A method performed by a first type of station (STA) in a WLAN system according to an aspect of the present disclosure may include: receiving, from a second type of STA, information related to at least one service period (SP) for the first type of STA among a plurality of first type of STAs; and performing frame exchange with at least one third type of STA associated with the first type of STA based on the information related to the at least one SP. The at least one SP may include an SP that restricts transmissions by STAs other than the first type of STA and the at least one third type of STA. The information related to the at least one SP may further include information about at least one other SP that allows at least one of at least one other first type of STA among the plurality of first type of STAs or at least one other third type of STA associated with the at least one other first type of STA to perform transmissions.

[0010] A method performed by a second type of station (STA) in a WLAN system according to an additional aspect of the present disclosure may include: setting information related to at least one service period (SP) based on information provided by a plurality of first type of STAs; and transmitting the information related to the at least one SP to the plurality of first type of STAs. The at least one SP includes an SP that restricts transmissions by STAs other than the first type of STA among the plurality of first type of STAs and at least one third type of STA associated with the first type of STA. The information related to the at least one SP may further include information about at least one other SP that allows at least one of at least one other first type of STA among the plurality of first type of STAs or at least one other third type of STA associated with the at least one other first type of STA to perform transmissions.

[0011] Technical effects

[0012] According to the present disclosure, a scheduling method and apparatus based on multi-AP operation in a WLAN system can be provided.

[0013] According to the present disclosure, a method and apparatus in a WLAN system can be provided, in which one AP participating in multi-AP operation schedules service periods (SPs) of at least one other AP.

[0014] The effects that can be achieved by the present disclosure are not limited to the above effects, and those skilled in the relevant art can clearly understand other effects not described herein through the following description. Brief description of the drawings

[0015] The drawings included as part of the specific embodiments for understanding the present disclosure provide embodiments of the present disclosure and describe the technical features of the present disclosure together with the specific embodiments.

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

[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 Is a diagram for explaining a link establishment process to which the present disclosure can be applied.

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

[0020] Figure 5 Is a diagram for explaining a CSMA / CA-based frame transmission operation 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 Is a diagram for explaining an example of an individual TWT operation to which the present disclosure can be applied.

[0024] Figure 9 Is a diagram for explaining an example of a broadcast TWT operation to which the present disclosure can be applied.

[0025] Figure 10 Is a diagram for explaining various transmission or reception techniques in a MAP environment to which the present disclosure can be applied.

[0026] Figure 11 Is a diagram for explaining the operation of a first type of STA according to the present disclosure.

[0027] Figure 12 Is a diagram for explaining the operation of a second type of STA according to the present disclosure.

[0028] Figure 13 Is a diagram for explaining information transmission or reception between a first type of STA, a second type of STA, and a third type of STA according to an example of the present disclosure.

[0029] Figure 14 Is a diagram for explaining information transmission or reception between a first type of STA, a second type of STA, and a third type of STA according to another example of the present disclosure.

[0030] Figure 15It is a diagram showing an example of the position of the SP for the first type of STA in the time domain according to the present disclosure. Detailed implementation

[0031] Hereinafter, embodiments according to the present disclosure will be described in detail with reference to the accompanying drawings. The detailed description disclosed through the drawings is to describe the exemplary embodiments of the present disclosure, rather than indicating the only embodiments 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.

[0032] In some cases, 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 concept of the present disclosure.

[0033] In the present disclosure, when an element is referred to as "connected", "combined" or "linked" to another element, it may include an indirect connection relationship and a direct connection relationship in which another element exists therebetween. 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.

[0034] In the present disclosure, terms such as "first", "second", etc. are only used to distinguish one element from another element and do not limit the element, unless otherwise specified, which does 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.

[0035] The terms used in the present disclosure are for describing specific embodiments and do not 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 "and / or " in the present disclosure have the same meaning unless otherwise specified.

[0036] Examples of the present disclosure can be applied to various wireless communication systems. For example, examples of the present disclosure can be applied to a wireless LAN system. For example, examples of the present disclosure can be applied to a wireless LAN based on the IEEE 802.11a / g / n / ac / ax standards. In addition, examples of the present disclosure can be applied to a wireless LAN based on the newly proposed IEEE 802.11be (or EHT) standard. Examples of the present disclosure can be applied to a wireless LAN based on the IEEE 802.11be version 2 standard corresponding to additional enhancement technologies of the IEEE 802.11be version 1 standard. Additionally, examples of the present disclosure can be applied to a wireless LAN based on a next-generation standard after IEEE 802.11be. Furthermore, examples of the present disclosure can be applied to a cellular wireless communication system. For example, it can be applied to a cellular wireless communication system based on the Long-Term Evolution (LTE) technology and the 5G New Radio (NR) technology based on the Third Generation Partnership Project (3GPP) standards.

[0037] Hereinafter, technical features to which examples of the present disclosure can be applied will be described.

[0038] Figure 1 A block diagram of a wireless communication device according to an embodiment of the present disclosure is illustrated.

[0039] Figure 1 The first device 100 and the second device 200 illustrated in can be replaced with various terms such as a terminal, a wireless device, a wireless transmit / receive unit (WTRU), a user equipment (UE), a mobile station (MS), a user terminal (UT), a mobile subscriber station (MSS), a mobile subscriber unit (MSU), a subscriber station (SS), an advanced mobile station (AMS), a wireless terminal (WT), or simply a user. Additionally, 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 can 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.

[0040] Figure 1 The devices 100 and 200 illustrated in can be referred to as a station (STA). For example, Figure 1The apparatuses 100 and 200 illustrated in the examples may be referred to by various terms such as a transmitting apparatus, a receiving apparatus, a transmitting STA, and a receiving STA. For example, the STAs 110 and 200 may perform an access point (AP) role or a non-AP role. That is, in the present disclosure, the STAs 110 and 200 may perform AP and / or non-AP functions. When the STAs 110 and 200 perform the AP function, they may be simply referred to as APs, and when the STAs 110 and 200 perform the non-AP function, they may be simply referred to as STAs. In addition, in the present disclosure, an AP may also be indicated as an AP STA.

[0041] Referring to Figure 1 , the first apparatus 100 and the second apparatus 200 may transmit and receive radio signals through various wireless LAN technologies (e.g., the IEEE 802.11 series). The first apparatus 100 and the second apparatus 200 may include interfaces for a media access control (MAC) layer and a physical layer (PHY) compliant with the IEEE 802.11 standard.

[0042] In addition, in addition to wireless LAN technologies, the first apparatus 100 and the second apparatus 200 may additionally support various communication standard (e.g., 3GPP LTE series, 5G NR series standards, etc.) technologies. In addition, the apparatuses of the present disclosure may be implemented in various apparatuses such as mobile phones, vehicles, personal computers, augmented reality (AR) devices, and virtual reality (VR) devices. In addition, the STAs in the present specification may support various communication services such as voice calls, video calls, data communication, autonomous driving, machine type communication (MTC), machine to machine (M2M), device to device (D2D), IoT (Internet of Things), etc.

[0043] The first device 100 may include one or more processors 102 and one or more memories 104, and may additionally include one or more transceivers 106 and / or one or more antennas 108. The 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 operation flowcharts included in the present disclosure. For example, after generating first information / signals by processing information in the memory 104, the processor 102 may transmit a wireless signal including the first information / signals through the transceiver 106. Additionally, the processor 102 may receive a wireless signal including second information / signals through the transceiver 106, and then store the information obtained by signal processing of the second information / signals 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 code including instructions for performing all or part of the processing controlled by the processor 102 or for performing the descriptions, functions, processes, suggestions, methods, and / or operation flowcharts included in 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., the IEEE 802.11 series). The transceiver 106 may be connected to the processor 102 and may transmit 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 with an RF (radio frequency) unit. In the present disclosure, a wireless device may mean a communication modem / circuit / chip.

[0044] The second device 200 may include one or more processors 202 and one or more memories 204, and may additionally include one or more transceivers 206 and / or one or more antennas 208. The 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 transmit wireless signals including the third information / signals through the transceiver 206. Additionally, the processor 202 may receive wireless signals including fourth information / signals through the transceiver 206, and then store the information obtained by signal processing of the fourth information / signals 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 performing all or part of the processing controlled by the processor 202 or for performing 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 technologies (e.g., the IEEE 802.11 series). The transceiver 206 may be connected to the processor 202 and may transmit 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 with an RF unit. In the present disclosure, a device may mean a communication modem / circuit / chip.

[0045] Hereinafter, the hardware components of apparatuses 100 and 200 will be described in more detail. Without being limited thereto, one or more protocol layers may be implemented by one or more processors 102 and 202. For example, one or more processors 102 and 202 may implement one or more layers (e.g., functional layers such as PHY and MAC). One or more processors 102 and 202 may generate one or more PDUs (Protocol Data Units) and / or one or more SDUs (Service Data Units) according to the descriptions, functions, procedures, suggestions, methods, and / or operation flowcharts disclosed in the present disclosure. One or more processors 102 and 202 may generate messages, control information, data, or information according to the descriptions, functions, procedures, suggestions, methods, and / or operation flowcharts disclosed in the present disclosure. One or more processors 102 and 202 may generate signals (e.g., baseband signals) including PDUs, SDUs, messages, control information, data, or information according to the functions, procedures, suggestions, and / or methods disclosed in the present disclosure to provide them to one or more transceivers 106 and 206. One or more processors 102 and 202 may receive signals (e.g., baseband signals) from one or more transceivers 106 and 206 according to the descriptions, functions, procedures, suggestions, methods, and / or operation flowcharts included in the present disclosure, and obtain PDUs, SDUs, messages, control information, data, or information.

[0046] One or more processors 102 and 202 may be referred to as a controller, a microcontroller, a microprocessor, or a microcomputer. One or more processors 102 and 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 Processor 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 and 202. The descriptions, functions, procedures, suggestions, methods, and / or operation flowcharts included in the present disclosure may be implemented by using firmware or software, and the firmware or software may be implemented to include modules, procedures, functions, etc. The firmware or software configured to execute the descriptions, functions, procedures, suggestions, methods, and / or operation flowcharts included in the present disclosure may be included in one or more processors 102 and 202, or may be stored in one or more memories 104 and 204 and driven by one or more processors 102 and 202. The descriptions, functions, procedures, suggestions, methods, and / or operation flowcharts included in the present disclosure may be implemented by using firmware or software in the form of codes, instructions, and / or instruction sets.

[0047] One or more memories 104, 204 may be connected to one or more processors 102, 202 and may store data, signals, messages, information, programs, code, instructions, and / or commands in various forms. One or more memories 104, 204 may be configured with ROM, RAM, EPROM, flash memory, hard disk drives, registers, cache memories, 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. Additionally, one or more memories 104, 204 may be connected to one or more processors 102, 202 through various technologies such as wired or wireless connections.

[0048] One or more transceivers 106, 206 may send user data, control information, wireless signals / channels, etc. mentioned in the methods and / or operation flowcharts, etc. 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 descriptions, functions, processes, suggestions, methods, and / or operation flowcharts, 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. Additionally, 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. Additionally, one or more transceivers 106, 206 may be connected to one or more antennas 108, 208, and one or more transceivers 106, 206 may be configured to send and receive user data, control information, wireless signals / channels, etc. mentioned in the descriptions, functions, processes, suggestions, methods, and / or operation flowcharts, 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 the received wireless signals / channels, etc. from RF band signals into baseband signals to process the 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 the 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 transceivers 106, 206 may include (analog) oscillators and / or filters.

[0049] For example, one of STAs 100 and 200 may perform the expected operations of an AP, and the other of STAs 100 and 200 may perform the expected operations of a non-AP STA. For example, Figure 1 transceivers 106 and 206 may perform the sending and receiving 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). Additionally, in the present disclosure, operations where various STAs generate transmission / reception signals or perform data processing or calculations on the transmission / reception signals in advance may be performed by Figure 1are executed by processors 102 and 202. For example, examples of operations for generating transmission / reception signals or performing data processing or calculations in advance for transmission / reception signals may include: 1) determining / acquiring / configuring / calculating / decoding / encoding bit information of fields (signals (SIG), short training fields (STF), long training fields (LTF), data, etc.) included in a PPDU; 2) determining / configuring / acquiring time resources or frequency resources (e.g., subcarrier resources) for fields (SIG, STF, LTF, data, etc.) included in a PPDU; 3) determining / configuring / acquiring a specific sequence (e.g., a pilot sequence, an STF / LTF sequence, an additional sequence applied to SIG) for fields (SIG, STF, LTF, data, etc.) included in a PPDU operation; 4) power control operations and / or power saving operations applied to a STA; 5) operations related to determining / acquiring / configuring / calculating / decoding / encoding, etc. of an ACK signal. Additionally, in the following examples, various information (e.g., information related to fields / sub-fields / control fields / parameters / power, etc.) used by various STAs to determine / acquire / configure / calculate / decode / encode transmission signals and reception signals may be stored in Figure 1 memories 104 and 204.

[0050] Hereinafter, a downlink (DL) may refer to a link for communication from an AP STA to a non-AP STA, and DL PPDUs / packets / signals may be transmitted and received through the DL. In DL communication, the transmitter may be part of the AP STA, and the receiver may be part of the non-AP STA. An uplink (UL) may refer to a link for communication from a non-AP STA to an AP STA, and UL PPDUs / packets / signals may be transmitted and received through the UL. In UL communication, the transmitter may be part of the non-AP STA, and the receiver may be part of the AP STA.

[0051] Figure 2 is a diagram illustrating an exemplary structure of a wireless LAN system to which the present disclosure may be applied.

[0052] The structure of a wireless LAN system may be composed of multiple components. A wireless LAN that supports STA mobility transparent to the upper layer may be provided through the interaction of multiple components. A basic service set (BSS) corresponds to the basic building block of a wireless LAN. Figure 2 Exemplarily, it is shown that there are two BSSs (BSS1 and BSS2), and two STAs included as members of each BSS (STA 1 and STA 2 are included in BSS1, and STA 3 and STA 4 are included in BSS2). Figure 2The ellipse representing the BSS can also be understood as representing the coverage area where the STAs included in the corresponding BSS maintain communication. This area can be referred to as the Basic Service Area (BSA). When an STA moves outside the BSA, it cannot directly communicate with other STAs within the BSA.

[0053] If the DS shown in Figure 2 is not considered, the most basic type of BSS in a wireless LAN is the Independent BSS (IBSS). For example, an IBSS can have a minimum form that only contains two STAs. For example, assuming other components are omitted, BSS1 that only contains STA 1 and STA 2 or BSS2 that only contains STA 3 and STA 4 can respectively correspond to representative examples of an IBSS. This configuration is possible when STAs can directly communicate without an AP. Additionally, in this type of wireless LAN, it is not pre-configured but can be configured when a LAN is needed, and this can be referred to as an ad-hoc network. Since an IBSS does not include an AP, there is no centralized management entity. That is, in an IBSS, STAs are managed in a distributed manner. In an IBSS, all STAs can be composed of mobile STAs, and access to the Distributed System (DS) is not allowed, thus forming a self-contained network.

[0054] The membership of STAs in a BSS can be dynamically changed by turning on or off STAs, entering or exiting the BSS area, etc. To become a member of a BSS, an STA can use synchronization processing to join the BSS. To access all services of the BSS infrastructure, an STA should be associated with the BSS. This association can be dynamically established and can include using the Distribution System Service (DSS).

[0055] The direct STA-to-STA distance in a wireless LAN may be limited by the PHY performance. In some cases, this distance limitation may be sufficient, but in some cases, communication between STAs at longer distances may be required. The Distributed System (DS) can be configured to support extended coverage.

[0056] DS means the structure for interconnecting BSSs. Specifically, as Figure 2As shown, the BSS can exist as an extended form of a network consisting of multiple BSSs. The DS is a logical concept and can be specified by the characteristics of the distributed system medium (DSM). In this regard, the wireless medium (WM) and the DSM can be logically separated. Each logical medium is used for a different purpose 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 structures) 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.

[0057] The DS can support mobile devices by providing seamless integration of multiple BSSs and providing the logical services necessary for addressing the addresses to the destination. Additionally, the DS can also include a component called a portal, which is used as a bridge for the connection between the wireless LAN and other networks (e.g., IEEE 802.X).

[0058] The AP enables access to the DS via the WM for the associated non-AP STA and refers to an entity that also has the STA function. The data movement between the BSS and the DS can be performed by the AP. For example, Figure 2 STA 2 and STA 3 shown in have the function of the STA and provide the function of allowing the associated non-AP STAs (STA 1 and STA 4) to access the DS. Additionally, since all APs basically correspond to STAs, all APs are addressable entities. The address used by the AP for communication on the WM is not necessarily the same as the address used by the AP for communication on the DSM. The BSS composed of an AP and one or more STAs can be called an infrastructure BSS.

[0059] 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. Additionally, when the controlled port is authenticated, the transmitted data (or frame) can be delivered to the DS.

[0060] In addition to the above DS structure, the extended service set (ESS) can also be configured to provide wide coverage.

[0061] An ESS refers to a network composed of a DS and BSSs with arbitrary size and complexity. An ESS can correspond to a set of BSSs connected to a DS. However, an ESS does not include the DS. The ESS network is characterized by being regarded as an IBSS in the logical link control (LLC) layer. STAs included in an ESS can communicate with each other, and a mobile STA can move from one BSS to another (within the same ESS) transparently to the LLC. APs included in an ESS can have the same service set identifier (SSID). The SSID is distinguished from the BSSID which is the identifier of a BSS.

[0062] The wireless LAN system does not assume anything about the relative physical positions of BSSs, and all of the following forms are possible. BSSs can partially overlap, which is a form commonly used to provide continuous coverage. Additionally, BSSs can be physically unconnected, and logically, there is no limit to the distance between BSSs. Additionally, BSSs can be physically located at the same position, which can be used to provide redundancy. Additionally, one (or more than one) IBSS or ESS network can physically exist in the same space as one (or more than one) ESS network. This can correspond to forms of an ESS network when an ad hoc network operates in the 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 at the same position.

[0063] Figure 3 is a diagram for explaining the link establishment process to which the present disclosure can be applied.

[0064] In order for an STA to establish a link with respect to a network and send / receive data, it first discovers the network, performs authentication, establishes an association, and needs to perform an authentication process for security. The link establishment process can also be referred to as a session initiation process or a session establishment process. Additionally, the processes of discovery, authentication, association, and security establishment in the link establishment process can be collectively referred to as an association process.

[0065] In step S310, the STA can perform a network discovery operation. The network discovery operation can include a scanning operation of the STA. That is, in order for the STA to access a network, it needs to find a network it can participate in. The STA should identify compatible networks before participating in a wireless network, and the process of identifying the networks existing in a specific area is called scanning.

[0066] Scanning schemes include active scanning and passive scanning. Figure 3A network discovery operation including an active scanning process is exemplarily illustrated. In active scanning, the STA performing the scan sends a probe request frame to discover which APs exist around it while moving across channels 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 can be the STA that last sent a beacon frame in the BSS of the channel being scanned. In a BSS, since the AP sends a beacon frame, the AP becomes the responder, and in an IBSS, the STAs in the IBSS rotate to send beacon frames, so the responder is not constant. For example, the STA that sends a probe request frame on channel 1 and receives a probe response frame on channel 1 can store the BSS-related information included in the received probe response frame, and can move to the next channel (e.g., channel 2), and perform the scan in the same way (i.e., send and receive probe requests / responses on channel 2).

[0067] Although not shown in Figure 3 it, the scan operation can be performed in a passive scanning manner. In passive scanning, the STA performing the scan waits for beacon frames while moving across channels. A 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 to allow the STA performing the scan to find the wireless network and participate in the wireless network. In a BSS, the AP is used to periodically send beacon frames, and in an IBSS, the STAs within the IBSS rotate to send beacon frames. When the STA performing the scan receives a beacon frame, the STA stores the information of the BSS included in the beacon frame, and while moving to another channel, records the beacon frame information in each channel. The STA that receives the beacon frame can store the BSS-related information included in the received beacon frame, move to the next channel, and perform the scan in the next channel in the same way. Comparing active scanning with passive scanning, the advantage of active scanning is that it has less latency and less power consumption than passive scanning.

[0068] After the STA discovers the network, the authentication process can be performed in step S320. To clearly distinguish it from the security establishment operation in step S340 to be described later, this authentication process can be referred to as the first authentication process.

[0069] The authentication process includes the following processes: 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.

[0070] The authentication frame includes an authentication algorithm number, an authentication transaction sequence number, a status code, a challenge text, a Robust Security Network (RSN), and a finite cyclic group, 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.

[0071] The STA can send an authentication request frame to the AP. The AP can determine whether to allow the authentication of the corresponding STA based on the information included in the received authentication request frame. The AP can provide the result of the authentication process to the STA through an authentication response frame.

[0072] After the STA is successfully authenticated, the association process can be performed in 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.

[0073] For example, the association request frame can include information related to various capabilities, a beacon listening interval, a Service Set Identifier (SSID), supported rates, supported channels, RSN, a mobility domain, supported operation classes, a Traffic Indication Map Broadcast Request (TIM broadcast request), interoperability service capabilities, etc. For example, the association response frame can 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 Indicator (RSNI), a mobility domain, a timeout interval (e.g., an association recovery time), overlapping BSS scan parameters, a TIM broadcast response, Quality of Service (QoS) mapping, etc. This corresponds to some examples of information that can be included in the association request / response frame, and can be replaced with other information, or additional information can also be included.

[0074] After the STA is successfully associated with the network, the security establishment process can be performed in step S340. The security establishment process in step S340 can be referred to as an authentication process through Robust Security Network Association (RSNA) request / response. The authentication process in step S320 is referred to as the first authentication process, and the security establishment process in step S340 can also simply be referred to as an authentication process.

[0075] The security establishment process in step S340 can, for example, include a process of establishing a private key using the Extensible Authentication Protocol over LAN (EAPOL) frame through a four-way handshake. Additionally, the security establishment process can be performed according to a security scheme not defined in the IEEE 802.11 standard.

[0076] Figure 4 It is a diagram for explaining the backoff process to which the present disclosure can be applied.

[0077] In a wireless LAN system, the basic access mechanism of the Media Access Control (MAC) is the 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 transmit, the AP and / or STA can perform a Clear Channel Assessment (CCA) of sensing the radio channel or medium during a predetermined time interval (e.g., the DCF Interframe Space (DIFS)). As a result of the sensing, if it is determined that the medium is idle, frame transmission is started through the corresponding medium. On the other hand, if the medium is detected to be occupied or busy, the corresponding AP and / or STA does not start its own transmission and can set a delay period for medium access (e.g., a random backoff period) and attempt frame transmission after waiting. By applying a random backoff period, since it is expected that multiple STAs will attempt frame transmission after waiting for different time periods, collisions can be minimized.

[0078] In addition, the IEEE 802.11 MAC protocol provides a Hybrid Coordination Function (HCF). The HCF is based on the DCF and the Point Coordination Function (PCF). The PCF is a polling-based synchronous access method and refers to a method in which all receiving APs and / or STAs are polled periodically to receive data frames. In addition, the HCF has an Enhanced Distributed Channel Access (EDCA) and an HCF Control Channel Access (HCCA). The EDCA is a contention-based access method that provides data frames to multiple users in a directed manner, and the HCCA uses a non-contention-based channel access method that utilizes a polling mechanism. In addition, the HCF includes a medium access mechanism for improving the Quality of Service (QoS) of the wireless LAN and can transmit QoS data during a Contention Period (CP) and a Contention Free Period (CFP).

[0079] Refer to Figure 4, operations based on a random backoff period will be described. When the occupied / busy medium becomes idle, multiple STAs can attempt to send data (or frames). As a method for minimizing collisions, each of the STAs can separately select a random backoff count and attempt to send after waiting for the corresponding slot time. The random backoff count has a pseudo-random integer value and can be determined as one of the values that vary from 0 to the value of CW. Here, CW is the contention window parameter value. The CW parameter is given the initial value of CWmin, but can take a value twice as large in the case 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 can be attempted while maintaining the CWmax value until the data transmission is successful, and when the data transmission is successful, the CWmin value is reset. The values of CW, CWmin, and CWmax are preferably set to 2n - 1 (n = 0, 1, 2,...).

[0080] When the random backoff process starts, the STA continuously monitors the medium during the countdown of the backoff slot according to the determined backoff count value. When monitoring the medium for occupancy, it stops the countdown and waits, and when the medium becomes idle, it resumes the remaining part of the countdown.

[0081] In Figure 4In the example, when the packet to be transmitted arrives at the MAC of STA 3, STA 3 can immediately transmit a frame 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 transmitted can also occur in each of STA 1, STA 2, and STA 5, and when the medium is monitored as idle, each STA waits for up to DIFS and then can perform a countdown of the backoff slots according to the randomly selected backoff count value of each STA. Assume that STA 2 selects the minimum backoff count value and STA 1 selects the maximum backoff count value. That is, an example is shown where the remaining backoff time of STA 5 is shorter than the remaining backoff time of STA 1 when STA 2 finishes the backoff count and starts frame transmission. STA 1 and STA 5 temporarily stop the countdown and wait while STA 2 occupies the medium. When the occupation of STA 2 ends and the medium becomes idle again, STA 1 and STA 5 wait for DIFS and restart the stopped backoff count. That is, frame transmission can start after counting down the remaining backoff slots for the remaining backoff time. Since the remaining backoff time of STA 5 is shorter than the remaining backoff time of STA 1, STA 5 starts frame transmission. While STA 2 occupies the medium, the data to be transmitted can also occur in STA 4. From the perspective of STA 4, when the medium becomes idle, STA 4 can wait for DIFS, then can perform a countdown according to the randomly selected backoff count value by STA 4, and start transmitting a frame. Figure 4 The example shows a situation where the remaining backoff time of STA 5 accidentally conflicts with the randomly selected backoff count value of STA 4. In this case, a conflict may occur between STA 4 and STA 5. When a conflict occurs, neither STA 4 nor STA 5 receives an ACK, so the data transmission fails. In this case, STA 4 and STA 5 can double the CW value, select a randomly selected backoff count value, and perform a countdown. While the medium is occupied due to the transmissions of STA 4 and STA 5, STA 1 waits. When the medium becomes idle, STA 1 waits for DIFS and then starts frame transmission after the remaining backoff time has passed.

[0082] As in Figure 4In the example, a data frame is a frame for transmitting data forwarded to a higher layer and can be transmitted after a backoff executed after the medium becomes idle and after DIFS. Additionally, a management frame is a frame for exchanging management information that is not forwarded to a higher layer and is transmitted after a backoff executed after an IFS such as DIFS or Point Coordination Function IFS (PIFS). As sub - type frames of the management frame, there are beacon, association request / response, re - association request / response, probe request / response, authentication request / response, etc. A control frame is a frame for controlling access to the medium. As sub - type frames of the control frame, there are Request to Send (RTS), Clear to Send (CTS), Acknowledgment (ACK), Power - Save Poll (PS - Poll), Block ACK (BlockAck), Block ACK Request (BlockACKReq), Null Data Packet Announcement (NDP Announcement), and Trigger, etc. If a control frame is not a response frame to a previous frame, it is sent after a backoff executed after DIFS, and if it is a response frame to a previous frame, it is sent without a backoff after Short IFS (SIFS). The type and sub - type of a frame can be identified by the type field and sub - type field in the Frame Control (FC) field.

[0083] A Quality of Service (QoS) STA can execute a backoff executed after Arbitration IFS (AIFS) for the access category (AC) to which the frame belongs (i.e., AIFS (where i is a value determined by the AC)), and then can send the frame. Here, frames that can use AIFS can be data frames, management frames, or control frames other than response frames.

[0084] Figure 5 is a diagram for explaining the CSMA / CA - based frame transmission operation to which the present disclosure can be applied.

[0085] As described above, in addition to the physical carrier sensing in which the STA directly senses the medium, the CSMA / CA mechanism includes virtual carrier sensing. Virtual carrier sensing aims to compensate for problems such as the hidden node problem that may occur in medium access. For virtual carrier sensing, the MAC of the STA can use the Network Allocation Vector (NAV). NAV is a value indicating the remaining time until the medium is available for the current use or for use by the STA having the right to use the medium to other STAs. Therefore, the value set to NAV corresponds to the period during which the STA transmitting the frame plans to use the medium, and during the corresponding period, STAs receiving the NAV value are prohibited from accessing the medium. For example, NAV can be configured based on the value of the "Duration" field in the MAC header of the frame.

[0086] In Figure 5In the example, it is assumed that STA 1 intends to send data to STA 2, and STA 3 is in a position where it can eavesdrop on some or all of the frames transmitted and received between STA 1 and STA 2.

[0087] To reduce the possibility of transmission collisions among multiple STAs in CSMA / CA-based frame transmission operations, a mechanism using RTS / CTS frames can be applied. In Figure 5 the example, when the transmission of STA 1 is being executed, as a result of the carrier sensing of STA 3, it can be determined that the medium is in an idle state. That is, STA 1 can correspond to a hidden node with respect to STA 3. Alternatively, in Figure 5 the example, it can be determined that when the transmission of STA 2 is being executed, the carrier sensing result of STA 3 indicates that the medium is in an idle state. That is, STA 2 can correspond to a hidden node with respect to STA 3. By exchanging RTS / CTS frames before performing data transmission and reception between STA 1 and STA 2, STAs outside the transmission range of either STA 1 or STA 2 or STAs outside the carrier sensing range of the transmission of STA 1 or STA 3 can refrain from attempting to occupy the channel during the data transmission and reception between STA 1 and STA 2.

[0088] Specifically, STA 1 can determine whether the channel is being used through carrier sensing. In terms of physical carrier sensing, STA 1 can determine the occupied or idle state of the channel based on the energy level or signal correlation detected in the channel. Additionally, in terms of virtual carrier sensing, STA 1 can use the Network Allocation Vector (NAV) timer to determine the channel occupancy state.

[0089] When the channel is in an idle state during DIFS, STA 1 can send an RTS frame to STA 2 after performing backoff. When STA 2 receives the RTS frame, STA 2 can send a CTS frame to STA 1 as a response to the RTS frame after SIFS.

[0090] If STA3 cannot overhear the CTS frame from STA 2 but can overhear the RTS frame from STA 1, STA 3 can use the duration information included in the RTS frame to set the NAV timer for the transmission period of the frames continuously transmitted thereafter (e.g., SIFS + CTS frame + SIFS + data frame + SIFS + ACK frame). Alternatively, if STA 3 can overhear the CTS frame from STA 2, even though STA 3 cannot overhear the RTS frame from STA 1, STA 3 can also use the duration information included in the CTS frame to set the NAV timer for the transmission period of the frames continuously transmitted thereafter (e.g., SIFS + data frame + SIFS + ACK frame). That is to say, if STA 3 can overhear one or more of the RTS frames or CTS frames from one or more of STA1 or STA 2, STA 3 can set the NAV accordingly. When STA 3 receives a new frame before the expiration of the NAV timer, STA3 can use the duration information included in the new frame to update the NAV timer. STA 3 does not attempt channel access until the NAV timer expires.

[0091] When STA 1 receives a CTS frame from STA 2, STA 1 can send a data frame to STA 2 after SIFS from the time point when the reception of the CTS frame is completed. When STA2 successfully receives the data frame, STA 2 can send an ACK frame to STA 1 after SIFS as a response to the data frame. When the NAV timer expires, STA 3 can determine whether the channel is being used through carrier sensing. When STA 3 determines during the DIFS period after the expiration of the NAV timer that the channel is not being used by other terminals, STA3 can attempt channel access after the contention window (CW) according to random backoff has elapsed.

[0092] Figure 6 It is a diagram for explaining an example of the frame structure used in a WLAN system to which the present disclosure can be applied.

[0093] With an instruction or primitive (meaning a set of instructions or parameters) from the MAC layer, the PHY layer can prepare the MAC PDU (MPDU) to be transmitted. For example, when receiving a command from the MAC layer to start transmission from the PHY layer, the PHY layer switches to the transmission mode, configures the information (e.g., data) provided by the MAC layer in the form of a frame, and transmits it. In addition, when the PHY layer detects a valid preamble of the received frame, the PHY layer monitors the header of the preamble and sends a command to the MAC layer notifying the start of reception by the PHY layer.

[0094] In this way, information transmission / reception in a wireless LAN system is performed in the form of frames, and for this purpose, the PHY layer protocol data unit (PPDU) format is defined.

[0095] The basic PPDU may include a Short Training Field (STF), a Long Training Field (LTF), a Signal (SIG) field, and a Data field. The most basic PPDU format (e.g., the non-HT (High Throughput) shown in Figure 7 can consist only of a Legacy-STF (L-STF), a Legacy-LTF (L-LTF), a Legacy-SIG (L-SIG) field, and a Data field. Additionally, 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 fields, non-legacy STF, non-legacy LTF (i.e., xx-SIG, xx-STF, xx-LTF (e.g., xx is HT, VHT, HE, EHT, etc.)) etc. may be included between the L-SIG field and the Data field.

[0096] The STF is a signal for signal detection, automatic gain control (AGC), diversity selection, precise time synchronization, etc., and the LTF is a signal for channel estimation and frequency error estimation. The STF and LTF can be referred to as signals for synchronization and channel estimation of the OFDM physical layer.

[0097] The SIG field may include various information related to PPDU transmission and reception. 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 can be determined based on the type of PPDU. For example, for non-HT, HT, VHT, or EHT PPDU, the value of the Length field can be determined to be a multiple of 3. For example, for HE PPDU, the value of the Length field can be determined to be a multiple of 3 + 1 or 3 + 2.

[0098] The data field may include a SERVICE field, a Physical Layer Service Data Unit (PSDU), and PPDU tail bits, 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 bits may be used to return the encoder to the 0 state. The padding bits may be used to adjust the length of the data field in predetermined units.

[0099] The MAC PDU is defined according to various MAC frame formats, and the basic MAC frame consists of a MAC header, a frame body, and a Frame Check Sequence (FCS). The MAC frame may be composed of MAC PDUs and transmitted / received through the PSDU of the data part in the PPDU format.

[0100] 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 sub-fields of the MAC header, refer to the IEEE 802.11 standard document.

[0101] The Null Data PPDU (NDP) format refers to a PPDU format that does not include a data field. In other words, the NDP refers to a frame format that includes the PPDU preamble of the general PPDU format (i.e., the L-STF, L-LTF, L-SIG fields, and additional non-conventional SIG, non-conventional STF, non-conventional LTF (if any)) and does not include the remaining part (i.e., the data field).

[0102] Figure 7 FIG. is an example of a PPDU defined in the IEEE 802.11 standard to which the present disclosure can be applied.

[0103] 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 a data field. The basic PPDU format may also be referred to as the non-HT PPDU format (as shown in (a) of Figure 7 ).

[0104] Compared with 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) of can be referred to as the HT mixed format. Additionally, an HT greenfield format PPDU can be defined, and this corresponds to a format (not shown) consisting of an HT-GF-STF, HT-LTF1, HT-SIG, one or more HT-LTFs, and a data field, excluding the L-STF, L-LTF, and L-SIG.

[0105] Compared to the basic PPDU format, an example of the VHT PPDU format (IEEE 802.11ac) additionally includes VHT SIG-A, VHT-STF, VHT-LTF, and VHT-SIG-B fields (as Figure 7 shown in (c) of .

[0106] 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, and packet extension (PE) fields (as Figure 7 shown in (d) of . Some fields can be excluded, or their lengths can 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). Additionally, the HE trigger-based (TB) PPDU format does not include the HE-SIG-B, and the length of the HE-STF field can vary up to 8 μs. The extended range (HE ER) SU PPDU format does not include the HE-SIG-B field, and the length of the HE-SIG-A field can vary up to 16 μs. For example, the RL-SIG can be configured to be the same as the L-SIG. Based on the presence of the RL-SIG, the receiving STA can know that the received PPDU is an HE PPDU or an EHT PPDU, which will be described later.

[0107] The EHT PPDU format can include Figure 7 the EHT MU (multi-user) in (e) of and Figure 7 the EHT TB (trigger-based) PPDU in (f) of . The EHT PPDU format is similar to the HE PPDU format in including an RL-SIG following the L-SIG, but can include a U (universal)-SIG, EHT-SIG, EHT-STF, and EHT-LTF following the RL-SIG.

[0108] 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.

[0109] Compared with the EHT MU PPDU, Figure 7 The EHT TB PPDU in (f) omits the EHT-SIG. A STA that receives a trigger for UL MU transmission (e.g., a trigger frame or a triggered response schedule (TRS)) can perform UL transmission based on the EHT TB PPDU format.

[0110] The L-STF, L-LTF, L-SIG, RL-SIG, U-SIG (general signal), and EHT-SIG fields can be encoded and modulated so that even a legacy STA can attempt to demodulate and decode, and can be mapped based on the determined subcarrier frequency spacing (e.g., 312.5 kHz). These can be referred to as pre-EHT modulation fields. Next, the EHT-STF, EHT-LTF, data, and PE fields can be encoded and modulated to 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 this field, and can be mapped based on the determined subcarrier frequency spacing (e.g., 78.125 kHz). These can be referred to as EHT modulation fields.

[0111] Similarly, in the HE PPDU format, the L-STF, L-LTF, L-SIG, RL-SIG, HE-SIG-A, and HE-SIG-B fields can be referred to as pre-HE modulation fields, and the HE-STF, HE-LTF, data, and PE fields can be referred to as HE modulation fields. Additionally, in the VHT PPDU format, the L-STF, L-LTF, L-SIG, and VHT-SIG-A fields can be referred to as non-VHT modulation fields, and the VHT STF, VHT-LTF, VHT-SIG-B, and data fields can be referred to as VHT modulation fields.

[0112] Included in Figure 7The U-SIG in the EHT PPDU format can be configured based on, for example, two symbols (e.g., two consecutive OFDM symbols). Each symbol (e.g., OFDM symbol) for the U-SIG can have a duration of 4 μs, and the U-SIG can have a total duration of 8 μs. Each symbol of the U-SIG can be used to transmit 26 bits of information. For example, each symbol of the U-SIG can be transmitted and received based on 52 data tones and 4 pilot tones.

[0113] The U-SIG can be constructed in units of 20 MHz. For example, if an 80 MHz PPDU is constructed, the U-SIG can be replicated. That is, the same 4 U-SIGs can be included in the 80 MHz PPDU. A PPDU with a bandwidth exceeding 80 MHz can include different U-SIGs.

[0114] For example, A uncoded bits can be sent through the U-SIG. The first symbol of the U-SIG (e.g., the U-SIG-1 symbol) can send the first X bits of information out of the total A bits of information, and the second symbol of the U-SIG (e.g., the U-SIG-2 symbol) can send the remaining Y bits of information out of the total A bits of information. The A bits of information (e.g., 52 uncoded bits) can 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 can be used to terminate the trellis structure of the convolutional decoder and can be set to 0.

[0115] The bit information sent through the U-SIG can be divided into version-independent bits and version-dependent bits. For example, the U-SIG can be included in Figure 7 a new PPDU format (e.g., the UHR PPDU format) not shown, and can 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 can be the same, and some or all of the version-dependent bits can be different.

[0116] For example, the size of the version-independent bits of the U-SIG can be fixed or variable. The version-independent bits can be assigned only to the U-SIG-1 symbol, or assigned to both the U-SIG-1 symbol and the U-SIG-2 symbol. The version-independent bits and the version-dependent bits can be called various names, such as the first control bit and the second control bit.

[0117] 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 of the transmitted / received PPDU (e.g., EHT, UHR, etc.). 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 the Transmission Opportunity (TXOP) and information about the BSS Color ID.

[0118] For example, the version-dependent bits of the U-SIG may include information that directly or indirectly indicates the type of the PPDU (e.g., SU PPDU, MU PPDU, TB PPDU, etc.).

[0119] The information required for PPDU transmission and reception may be included in the U-SIG. For example, the U-SIG may also include information about the bandwidth, information about the MCS technique applied to non-traditional SIGs (e.g., EHT-SIG or UHR-SIG, etc.), information indicating whether the DCM (Dual Carrier Modulation) technique (e.g., a technique for achieving an effect similar to frequency diversity by reusing the same signal on two subcarriers) is applied to non-traditional SIGs, information about the number of symbols for non-traditional SIGs, information about whether non-traditional SIGs are generated across the entire frequency band.

[0120] Some of the information required for PPDU transmission and reception may be included in the U-SIG and / or non-traditional SIGs (e.g., EHT-SIG or UHR-SIG, etc.). For example, information about the type of non-traditional LTF / STF (e.g., EHT-LTF / EHT-STF or UHR-LTF / UHR-STF, etc.), information about the length of non-traditional LTF and the CP (Cyclic Prefix) length, information about the GI (Guard Interval) applicable to non-traditional LTF, information about the preamble puncturing applicable to the PPDU, information about the Resource Unit (RU) allocation, etc. may be included only in the U-SIG, included only in the non-traditional SIG, or may be indicated by a combination of the information included in the U-SIG and the information included in the non-traditional SIG.

[0121] Preamble puncturing may represent the transmission of the following PPDU, where there is no signal in one or more frequency units among 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 larger.

[0122] In Figure 7In an example, non - traditional SIGs such as HE - SIG - B and EHT - SIG can include control information for receiving STAs. The non - traditional SIG can be sent on at least one symbol, and one symbol can have a length of 4 μs. Information about the number of symbols for EHT - SIG can be included in a previous SIG (e.g., HE - SIG - A, U - SIG, etc.).

[0123] Non - traditional SIGs such as HE - SIG - B and EHT - SIG can include a common field and user - specific fields. The common field and user - specific fields can be encoded separately.

[0124] In some cases, the common field can be omitted. For example, in a compressed mode that does not apply OFDMA (Orthogonal Frequency Division Multiple Access), the common field can be omitted, and multiple STAs can receive a PPDU (e.g., the data field of the PPDU) through the same frequency band. In a non - compressed mode that applies OFDMA, multiple users can receive a PPDU (e.g., the data field of the PPDU) through different frequency bands.

[0125] The number of user - specific fields can be determined based on the number of users. One user block field can include up to two user fields. Each user field can be associated with MU - MIMO allocation or can be associated with non - MU - MIMO allocation.

[0126] The common field can include CRC bits and tail bits. The length of the CRC bits can be determined to be 4 bits, and the length of the tail bits can be determined to be 6 bits and set to 000000. The common field can include RU allocation information. The RU allocation information can include information about the positions of the RUs assigned to multiple users (i.e., multiple receiving STAs).

[0127] An RU can include multiple sub - carriers (or tones). When sending signals to multiple STAs based on OFDMA technology, RUs can be used. Additionally, even when sending signals to one STA, RUs can be defined. Resources can be allocated for non - traditional STF, non - traditional LTF, and data fields in units of RUs.

[0128] The RU of an applicable size can be defined according to the PPDU bandwidth. The RU can be defined identically or differently for the applied PPDU format (e.g., HE PPDU, EHT PPDU, UHR PPDU, etc.). For example, in the case of an 80 MHz PPDU, the RU layouts of the HE PPDU and the EHT PPDU can be different. The applicable RU size, the number of RUs, and the RU positions, the DC (direct current) subcarrier positions and number, the null subcarrier positions and number, the guard subcarrier positions and number, etc. for each PPDU bandwidth can be referred to as a tone plan. For example, the tone plan for a high bandwidth can be defined in the form of multiple iterations of a low bandwidth tone plan.

[0129] RUs of various sizes can be defined as 26-tone RUs, 52-tone RUs, 106-tone RUs, 242-tone RUs, 484-tone RUs, 996-tone RUs, 2×996-tone RUs, 3×996-tone RUs, etc. An MRU (multi-RU) is different from multiple individual RUs and corresponds to a set of subcarriers composed of multiple RUs. For example, an MRU can be defined as 52 + 26 tones, 106 + 26 tones, 484 + 242 tones, 996 + 484 tones, 996 + 484 + 242 tones, 2×996 + 484 tones, 3×996 tones, or 3×996 + 484 tones. Additionally, the multiple RUs constituting an MRU can be continuous or non-continuous in the frequency domain.

[0130] The specific size of an RU can be reduced or extended. Therefore, the specific size (i.e., the number of corresponding tones) of each RU in this disclosure is illustrative rather than restrictive. Additionally, in this disclosure, within a predetermined bandwidth (e.g., 20 MHz, 40 MHz, 80 MHz, 160 MHz, 320 MHz...), the number of RUs can vary according to the RU size.

[0131] Figure 7 The name of each field in the PPDU format is exemplary, and the scope of this disclosure is not limited by these names. Additionally, the examples of this disclosure can be applied to Figure 7 the PPDU format shown in Figure 7 and new PPDU formats that exclude some fields and / or add some fields based on the

[0132] Target Wake Time (TWT)

[0133] Hereinafter, the target wake-up time (TWT) is described.

[0134] TWT is a power saving (PS) technique that can improve the energy efficiency of non-AP STAs by defining a service period (SP) between an AP and non-AP STAs and sharing information about the SP with each other to reduce medium contention. In the TWT setup step, the STA that executes requests / suggestions / requirements, etc. can be called a TWT requesting STA. In addition, the AP that responds to the corresponding request, such as accepting / rejecting, can be called a TWT responding STA. The setup step may include the TWT request of the STA to the AP, the type of TWT operation to be executed, and the process of determining / defining the frame type to be sent or received. TWT operations can be divided into individual TWT and broadcast TWT.

[0135] Figure 8 It is a diagram for explaining an example where the individual TWT operation of the present disclosure can be applied.

[0136] Individual TWT is a mechanism in which an AP and non-AP STAs perform data exchange after negotiating the wake / sleep state of the non-AP STA by sending or receiving TWT request / response frames. In Figure 8 the example, the AP and STA 1 can form a trigger-enabled TWT agreement through TWT request frames and TWT response frames. Here, the method used by STA 1 is the pleading TWT method, which is a method in which when STA 1 sends a TWT request frame to the AP, STA 1 receives information for TWT operation from the AP through the TWT response frame. On the other hand, STA 2 that executes the non-pleading TWT method can receive information about the trigger-enabled TWT agreement configuration from the AP through a non-pleading TWT response. Specifically, STA 2 can calculate the next TWT by adding a specific amount to the current TWT value. During the trigger-enabled TWT SP, the AP can send a trigger frame to the STA. The trigger frame can notify the STA that the AP has buffered data. In response to this, STA 1 can notify the AP of its wake state by sending a PS poll frame. In addition, STA 2 can notify the AP of its wake state by sending a QoS null frame. Here, the data frames sent by STA 1 and STA 2 can be frames in the form of TB PPDU. The AP that confirms the states of STA 1 and STA 2 can send a DL MU PPDU to wake up the STA. When the corresponding TWT SP expires, STA 1 and STA 2 can switch to the sleep state.

[0137] Figure 9 It is a diagram for explaining an example where the broadcast TWT operation of the present disclosure can be applied.

[0138] The broadcast TWT is a TWT in which a non-AP STA (or TWT-scheduled STA) obtains information such as the target beacon transmission time (TBTT) and the listening interval by sending or receiving TWT request / response frames to / from an AP (or TWT-scheduling STA). Here, a negotiation operation for the TBTT can be performed. Based on this, the AP can define a frame that will include scheduling information for the TWT by means of a beacon frame. In Figure 9 , STA 1 performs a solicited TWT operation, and STA 2 performs an unsolicited TWT operation. The AP can send a DL MU PPDU after triggering to confirm the wake-up state of the STA by the AP. This can be the same as the process of the individual TWT. In the broadcast TWT, the TWT SP including the beacon frame enabled trigger can be repeated several times at regular intervals.

[0139] The delivery of TWT information can be performed by means of a TWT information frame and a TWT information element.

[0140] With the recent explosion of wired and wireless traffic, delay-sensitive traffic has also increased significantly. Delay-sensitive traffic includes real-time audio / video transmission, and with the proliferation of multimedia devices, the demand for supporting such traffic in a wireless environment has increased. However, compared with a wired environment, many things need to be considered to support delay-sensitive traffic in a wireless environment. This is because the transmission speed in a wireless environment is lower than that in a wired environment, and the interference problem from the surrounding environment must also be considered. Specifically, in a WLAN system, multiple STAs must equally compete for the occupancy of the medium in the industrial, scientific, and medical (ISM) band. Therefore, compared with a cellular communication network based on radio resource scheduling by a central base station, it is relatively more difficult to support delay-sensitive traffic. The present disclosure describes a new method for supporting delay-sensitive traffic in a WLAN system.

[0141] In the present disclosure, the delay can refer to the delay defined in the IEEE 802.11 series of standards. For example, it can refer to the time starting from when the frame to be sent enters the queue of the MAC layer of the sending STA until the transmission of the sending STA is successfully completed in the PHY layer, and until the corresponding frame is deleted from the queue of the MAC layer of the sending STA after the sending STA receives an ACK / block ACK, etc. from the receiving STA. In addition, in the present disclosure, a non-AP STA that supports the transmission of delay-sensitive data can be referred to as a low-delay STA. And data other than delay-sensitive data can be referred to as regular data.

[0142] Since the AP configures a special broadcast TWT for low-latency STAs that send latency-sensitive data, a restricted TWT (restricted TWT, r-TWT) can support ensuring the data transmission possibility of low-latency STAs prior to other STAs. The STA can establish membership for at least one r-TWT schedule with the AP. Here, the r-TWT agreement can be established through the same process as the broadcast TWT agreement, and the broadcast TWT element for this can be defined to include an r-TWT parameter set field. For example, the r-TWT parameter set can refer to a specific broadcast TWT parameter set field different from other broadcast TWT parameter set fields. In other words, the r-TWT parameter set field can correspond to a special case of the broadcast TWT parameter set field. In addition, the AP can announce the r-TWT SP.

[0143] Basically, if another STA that supports r-TWT operation is a TXOP holder, the TXOP must end before the start time of the r-TWT SP announced in the associated AP. Thus, the STA associated with the corresponding r-TWT (i.e., the low-latency STA) can perform traffic transmission or reception prior to other STAs within the r-TWT SP.

[0144] In the present disclosure, as described above, the low-latency STA associated with a specific r-TWT is referred to as the STA of the member r-TWT schedule, and other STAs are referred to as non-member STAs. The non-member STA has the ability to support r-TWT operation, but it may not be a member of any r-TWT, or may support r-TWT operation and may be a member of another r-TWT, or may be a STA that does not have the ability to support r-TWT operation.

[0145] A STA (e.g., a low-latency STA) that supports the operation of a restricted SP (or r-TWT SP) for broadcast TWT can notify the AP that latency-sensitive data must be sent based on r-TWT operation. If the AP supports r-TWT operation / mode, the AP can send a frame including scheduling information of the TWT requested by each STA to the low-latency STA and other STAs. For example, to perform the operation for r-TWT, a non-AP STA can obtain r-TWT-related information from the AP through a beacon frame, a probe response frame, a (re)association response frame, or other frame formats not yet defined (e.g., frames for broadcast, announcement, and advertisement).

[0146] According to the restricted TWT operation, a separate TXOP can be ensured within the r-TWT SP by using, for example, NAV or silent intervals such as (MU)RTS / CTS or CTS-to-self (i.e., access by other STAs is restricted). Before a specific r-TWT SP starts, if there is a TXOP of another STA (i.e., a non-member STA) other than the STA having membership for the specific r-TWT scheduling, the specific r-TWT SP must stop. Also, a TXOP of another STA (i.e., a non-member STA) can be additionally executed after the specific r-TWT SP ends.

[0147] Multi-Access Point (MAP) Operation

[0148] Hereinafter, examples of the present disclosure for multi-access point (MAP) operation will be described.

[0149] MAP operation can be defined as an operation between a master AP (or a sharing AP) and a slave AP (or a shared AP).

[0150] The master AP serves to initiate and control the MAP operation for transmission or reception between multiple APs. The master AP groups the slave APs and manages the links with the slave APs to share information among the slave APs. The master AP manages the information of the BSS configured with the slave APs and the information of the STAs associated with the corresponding BSS.

[0151] The slave APs can be associated with the master AP and share control information, management information, and data traffic with each other. The slave APs perform the basic functions of an AP that can establish a BSS in the wireless LAN in the same manner.

[0152] The STAs in the MAP operation can be associated with the slave APs or the master AP to configure a BSS.

[0153] In the MAP environment, the master AP and the slave APs can perform direct transmission or reception with each other. The master AP and the STAs may not be able to perform direct transmission or reception with each other. A slave AP (e.g., a slave AP associated with an STA) can perform direct transmission or reception with the STA. One of the slave APs can become the master AP.

[0154] The MAP operation is a technique in which at least one AP sends and receives information to / from at least one STA. For example, techniques such as coordinated-time division multiple access (C-TDMA) that divides the allocation among APs on the time axis, coordinated-orthogonal frequency division multiple access (C-OFDMA) that divides the allocation among APs on the frequency axis, coordinated-space reuse (C-SR) technique that uses spatial reuse, etc. can be applied to the MAP operation. Alternatively, C-BF (coordinated beamforming) or joint beamforming techniques that cooperatively perform simultaneous transmission or reception can also be applied to the MAP operation.

[0155] Figure 10 It is a diagram for explaining various transmission or reception techniques in the MAP environment to which the present disclosure can be applied.

[0156] When a BSS AP performs transmission to a BSS STA as in the existing method, it can be referred to as single transmission (STX). In STX, there is a problem that the performance of transmission or reception of users / STAs located at the cell edge is degraded due to interference with adjacent APs. For example, as Figure 10 shown in (a) of, when AP1 and AP2 simultaneously perform transmission to STA 1 and STA 2 in the same frequency bandwidth, a conflict may occur on the wireless medium.

[0157] In the MAP technology, performance can be improved by a method for reducing inter-symbol interference (ISI) through cooperation or joint execution of transmission among neighbor APs. For example, in Figure 10 the C-OFDMA method of (b), AP1 can perform transmission to STA1 in the first bandwidth, and at the same time, AP2 can perform transmission to STA 2 in the second bandwidth, thus avoiding interference. Figure 10 The example in (c) of shows the cooperative beamforming or nulling technique, in which when AP1 performs transmission to STA 1, it nulls the interference to AP2 and / or STA 2, and when AP2 performs transmission to STA 2, it nulls the interference to AP1 and / or STA 1. Figure 10 The example in (d) of shows an AP selection method in which an AP with good channel conditions among adjacent APs performs transmission. As in the example of Figure 10 shown in (e), a joint transmission (JTX) or joint reception (JRX) in which multiple APs cooperate to simultaneously perform transmission or reception can be applied, and further, joint MU-MIMO can be supported.

[0158] Scheduling Based on Multi-AP Operation

[0159] As described above, a method is applied in which STAs (e.g., AP STAs and non-AP STAs) in an existing WLAN system attempt to access the wireless medium based on carrier sensing, or in which an AP STA provides scheduling information for uplink transmission to non-AP STAs by triggering, or in which an AP STA sets a time period (e.g., an SP based on r-TWT) to restrict the transmission of STAs other than specific non-AP STAs. In contrast, in multi-AP operation, one AP can act as the primary AP or the shared AP, and at least one other AP can act as the secondary AP or the shared-by AP, so it is necessary to effectively schedule the time resources for multiple APs and non-AP STAs associated with the corresponding APs to perform transmissions.

[0160] In the following example, in a multi-AP operation group, a STA acting as the secondary (or shared-by) AP can be referred to as a first-type STA, a STA acting as the primary (or shared) AP can be referred to as a second-type STA, and a non-AP STA associated with the secondary AP or the primary AP can be referred to as a third-type STA.

[0161] Examples of the present disclosure are described by assuming a multi-AP operation group, but the scope of the present disclosure is not limited thereto, and even when a STA belongs to multiple multi-AP operation groups, it can perform operations corresponding to the types (e.g., first type, second type, or third type) of the corresponding STAs within each multi-AP operation group. In other cases, a STA can act as the primary AP role, the secondary AP role, or the non-AP STA role within the corresponding group according to the settings of the multi-AP operation group to which it belongs. For example, a STA can act as the primary AP role in one group and the secondary AP role in another group.

[0162] The following describes various examples of the present disclosure for new scheduling methods based on or requiring support for multi-AP operation.

[0163] Figure 11 is a diagram for illustrating the operation of a first-type STA according to the present disclosure.

[0164] Figure 11 The first-type STA in the example of can correspond to Figure 13 or Figure 14 one of the first-type STA 1, the first-type STA 2, or the first-type STA 3 in the example of, and can be referred to as a secondary AP STA or a shared-by AP STA in multi-AP operation.

[0165] Figure 11 The second-type STA in the example of can correspond to Figure 13 or Figure 14a second type of STA in the example, and may be referred to as a primary AP STA or a shared AP STA in a multi-AP operation.

[0166] Figure 11 at least one third type of STA in the example may correspond to the following described Figure 13 or Figure 14 the third type of STA A and the third type of STA B in the example, or may correspond to the third type of STA C, or may correspond to the third type of STA D, the third type of STA E, and the third type of STA F, and may correspond to at least one non-AP STA associated with a slave AP STA or a shared AP STA in a multi-AP operation.

[0167] In this way, a multi-AP operation group may include a second type of STA and multiple (or at least one) first type of STAs. Each first type of STA may be associated with at least one third type of STA.

[0168] In S1110, the first type of STA may receive information related to the SP for multiple first type of STAs from the second type of STA.

[0169] When the second type of STA provides the SP for multiple first type of STAs, it may include scheduling, allocation, guarantee, and sharing of the SP. The SP-related information may include information directly indicating the SP or information for determining the SP.

[0170] When Figure 11 the operation in is performed by one (e.g., STA1) of multiple first type of STAs (e.g., STA 1, STA 2, and STA 3), the information related to at least one SP may include the information related to at least one SP for STA 1, and may additionally include the information related to at least one SP for STA2 or STA3. STA 1 may identify the information related to at least one SP provided to it, and STA2 and STA3 may also respectively identify the information related to at least one SP provided to them.

[0171] For example, at least one SP for STA 1 may include an SP that restricts STAs other than at least one third type of STA (e.g., STA A and STA B) associated with the STA and STA 1 from transmitting.

[0172] For example, the information related to at least one SP for multiple first-type STAs may also include information about at least one other SP that allows additional first-type STAs (e.g., STA 2, STA 3, …) or additional third-type STAs (e.g., STA C, STA D, STA E, STA F, …) to transmit.

[0173] In S1120, the first-type STA may perform frame exchange with at least one third-type STA associated with it based on the information related to at least one SP.

[0174] For example, STA1 may identify the information related to at least one SP regarding it from the information related to at least one SP for multiple first-type STAs, and may perform frame exchange with the third-type STAs (e.g., STA A and STA B) associated with it based on this. In at least one corresponding SP, the transmissions of other STAs (e.g., first-type STA 2 and first-type STA3, and third-type STAC, third-type STA D, third-type STA E, and third-type STA F) are restricted.

[0175] For example, STA2 may identify the information related to at least one SP regarding it from the information related to at least one SP for multiple first-type STAs, and may perform frame exchange with the third-type STA (e.g., STAC) associated with it based on this. In at least one corresponding SP, the transmissions of other STAs (e.g., first-type STA 1 and first-type STA 3, and third-type STA A, third-type STAB, third-type STAD, third-type STA E, and third-type STA F) are restricted.

[0176] For example, STA3 may identify the information related to at least one SP regarding it from the information related to at least one SP for multiple first-type STAs, and may perform frame exchange with the third-type STAs (e.g., STAD, STA E, and STAF) associated with it based on this. In at least one corresponding SP, the transmissions of other STAs (e.g., first-type STA 1 and first-type STA 2, and third-type STA A, third-type STA B, and third-type STA C) are restricted.

[0177] In Figure 11In the example, the information related to at least one SP for multiple first-type STAs generated or set by the second-type STA can be based on the predetermined information sent from at least one first-type STA among the multiple first-type STAs to the second-type STA. For example, the predetermined information can include the information provided by the third-type STA associated with each first-type STA. The information provided by the third-type STA can include, for example, the information about the buffer amount of the latency-sensitive traffic.

[0178] For example, the first-type STA can send the corresponding information to the second-type STA without additional processing of the information provided by the third-type STA. In addition, the information related to at least one SP provided by the second-type STA can include the information indicating at least one SP for each third-type STA, and the first-type STA can send the corresponding information to the third-type STA without additional processing of it.

[0179] Additionally or alternatively, the first-type STA can generate or set the information to be provided to the second-type STA based on the information provided by the third-type STA. For example, STA 1 can generate or set the information to be sent to the second-type STA based on the information received from STA A and STA B. For example, the information provided by the first-type STA to the second-type STA can include at least one of the information about the minimum interval (i.e., the time interval between SPs when multiple SPs are allocated), the maximum interval, the minimum duration, the maximum duration, or the start time of the SP requested by the corresponding first-type STA, and additionally or alternatively, can include the information about the total amount of data buffered by the corresponding first-type STA and at least one third-type STA associated with the corresponding first-type STA.

[0180] In addition, the first-type STA can determine at least one SP to be indicated to the third-type STA associated with it based on the information related to at least one SP provided by the second-type STA. For example, STA 1 can determine the SPs commonly or separately allocated to STA A and STA B within at least one SP allocated from the second-type STA. The information indicating at least one SP determined by the first-type STA can be sent to the corresponding third-type STA.

[0181] For example, the information related to at least one SP for multiple first-type STAs provided by a second-type STA may include the number of multiple first-type STAs, identification information for each of the multiple first-type STAs, information about the SPs assigned to each of the multiple first-type STAs, and so on. For example, the information about the SP assigned to a first-type STA may include information such as the identification information of the first-type STA, the interval for the assigned SP (i.e., the time interval between SPs when multiple SPs are assigned), the duration, the start time, and so on.

[0182] In this way, the information related to at least one SP for multiple first-type STAs can be generated or set through a negotiation process between multiple first-type STAs and one second-type STA. For example, a first-type STA can provide the information obtained from a third-type STA associated with it to the second-type STA by responding to a request from the second-type STA, either as is or after processing, even without a request from the second-type STA. In addition, a first-type STA can request information about at least one SP from the second-type STA. The other party can return information accepting or rejecting the information exchanged between the first-type STA and the second-type STA, and through this process, the information related to at least one SP assigned to multiple first-type STAs (and multiple third-type STAs) can be determined.

[0183] The SPs assigned to different first-type STAs may not overlap in the time domain or may partially (or completely) overlap. In the overlapping time domain region, one first-type STA with priority among different first-type STAs (and at least one third-type STA associated with the corresponding first-type STA) can perform transmission and reception (i.e., frame exchange). This priority can be determined based on a predetermined rule, and the second-type STA can signal information indicating the first-type STA with priority.

[0184] Figure 11 The method described in the example of Figure 1 can be executed by the first device 100 in Figure 1 For example, at least one processor 102 of the first device 100 in Figure 11 can be configured to receive information about at least one SP for multiple devices from the second device 200, and perform frame exchange with a third device associated with it based on the corresponding information. In addition, at least one memory 104 of the first device 100 can store instructions for executing the method described in the example of

[0185] Figure 12 This is a diagram for explaining the operation of a second type of STA according to the present disclosure.

[0186] Figure 12 The first type of STA, the second type of STA, and the third type of STA in the example of Figure 11 are the same as those described by referring to Figure 13 and Figure 14 in the description of

[0187] In S1210, the second type of STA can set information related to at least one SP for multiple corresponding first type of STAs based on the information provided by multiple first type of STAs.

[0188] Since the description of the example of Figure 11 can be applied to the information provided by multiple first type of STAs (or at least one of them) to the second type of STA and the information related to at least one SP for multiple first type of STAs, the repeated description is omitted.

[0189] In S1220, the second type of STA can send information related to at least one SP to multiple first type of STAs.

[0190] Therefore, each first type of STA can determine at least one SP that is limitedly allocated to it (i.e., other first type of STAs and third type of STAs are not allowed to send and receive) based on the information sent by the second type of STA, and can perform frame sending and receiving with at least one third type of STA associated with it based on this.

[0191] Figure 12 The method described in the example of Figure 1 can be executed by the second device 200 in Figure 1 For example, at least one processor 202 of the second device 200 in Figure 12 can be configured to set information related to at least one SP based on the information provided by multiple first devices 100, and send the corresponding information to multiple first devices 100. In addition, at least one memory 204 of the second device 200 can store instructions for executing the method described in the example of

[0192] Figure 11 and Figure 12 when executed by at least one processor 202. Figure 11 and Figure 12 The examples of

[0193] In the embodiments described below, as a representative example to which the present disclosure is applied, the SP is described as a time domain unit provided to a plurality of first type STAs (or a plurality of third type STAs), but the term SP is not limited to the term defined in the r-TWT, and the embodiments described below can be equivalently applied to time units under other names that allow transmission and reception of a specific STA while restricting transmission and reception of other STAs.

[0194] Embodiment 1

[0195] This embodiment relates to a method in which the SP for all STAs (i.e., the first type STAs corresponding to the shared AP STA or the slave AP, and the third type STAs corresponding to the non-AP STAs associated with the first type STAs) is determined by a second type STA (e.g., the shared AP or the master AP). Information related to the corresponding SP can be sent from the second type STA to the first type STA, and through the first type STA to the third type STA. In other words, frame exchange can be performed between the first type STA and the third type STA within the allocated SP according to the scheduling of the second type STA.

[0196] Figure 13 It is a diagram for explaining information transmission or reception among the first type STA, the second type STA, and the third type STA according to an example of the present disclosure.

[0197] In Figure 13 In the example of (a), the third type STA can be associated with the first type STA instead of the second type STA. Here, the first type STA can obtain information about the third type STA associated with it. The first type STA can send all or part of the data (e.g., a part of the data required by the second type STA) required or obtained during the process of establishing an association with each third type STA to the second type STA.

[0198] For example, the first type STA 1 can obtain information T_A about the buffered data of the third type STA A, and information T_B about the buffered data of the third type STA B. The first type STA1 can send T_A and T_B to the second type STA. Similarly, the remaining first type STA 2 or first type STA 3 can also send information T_C about the buffered data of the third type STA C associated with it, or information T_D, T_E, T_F about the buffered data of STAs D, E, and F to the second type STA.

[0199] In Figure 13In the example of (b), the second type of STA can provide scheduling information (e.g., information related to the SP) to each first type of STA based on the information of the third type of STA received from the first type of STA. For example, the second type of STA can receive from the first type of STA the information of the third type of STA that requests the r-TWT SP among the third type of STAs. The second type of STA can allocate an r-TWT SP of an appropriate length to each third type of STA based on the information of the delay-sensitive traffic that is scheduled to be sent and received (or buffered) by each third type of STA received from the first type of STA. The first type of STA can receive from the second type of STA the information related to the r-TWT SP allocated to the third type of STA associated therewith, and based on this, can perform the sending and receiving of the delay-sensitive traffic with the third type of STA.

[0200] For example, the second type of STA can schedule the SP for STA A and the SP for STA B, and provide the information SP_A and SP_B indicating this to the first type of STA 1. The first type of STA 1 can send SP_A and SP_B to STA A and STA B respectively. Similarly, the second type of STA can provide the first type of STA 2 or the first type of STA 3 with the information indicating the SPs for the third type of STAs C or D, STA E, and STA F associated with the corresponding first type of STA, and STA2 or STA 3 can send SP_C or SP_D, SP_E, and SP_F to STA C or STAD, STA E, and STA F.

[0201] For example, the SPs SP_A, SP_B, SP_C, SP_D, SP_E, and SP_F provided by the second type of STA can be included in one frame or element, or can be included in multiple frames or elements. Therefore, in addition to the scheduling information of the third type of STA associated therewith, one first type of STA can also receive the scheduling information of the third type of STA associated with at least one other first type of STA.

[0202] In this way, the second type of STA can schedule time resources for data transmission and reception of all third type of STAs and the first type of STA. Correspondingly, the first type of STA can perform a simple operation for transmitting scheduling information, and the second type of STA can have the ability to support complex operations for performing scheduling by considering information about all STAs in the multi-AP operation group. In addition, in this embodiment, in the case where the BSS of the first type of STA and the BSS of the second type of STA are different and the third type of STA is associated with the first type of STA rather than the second type of STA, the second type of STA can perform scheduling for the third type of STA based on information sent from the first type of STA (e.g., information about the third type of STA) without establishing an association between the second type of STA and the third type of STA.

[0203] Embodiment 2

[0204] This embodiment relates to a method for the second type of STA to provide an SP to the first type of STA. The first type of STA can autonomously schedule the transmission and reception of the third type of STA associated with it within the SP provided by the second type of STA. In other words, the SP provided by the second type of STA can correspond to a superset on the time domain region of the SP, where frame exchange between the first type of STA and the third type of STA is allowed, and the first type of STA can determine the SP (i.e., the time domain region corresponding to all or part of the superset) allocated to the third type of STA associated with it without scheduling the second type of STA.

[0205] In Embodiment 1, the second type of STA receives information about all third type of STAs associated with the first type of STA to perform scheduling (i.e., allocate an SP) for each third type of STA, while in Embodiment 2, the second type of STA allocates the entire SP required for data transmission and reception (with the third type of STA) to the first type of STA without the need for all information about the third type of STAs associated with the first type of STA. Each first type of STA can perform scheduling for each third type of STA associated with it by subdividing the SP allocated from the second type of STA.

[0206] Embodiment 2-1

[0207] Figure 14 It is a diagram for illustrating information transmission or reception among the first type of STA, the second type of STA, and the third type of STA according to another example of the present disclosure.

[0208] In Figure 14In the example of (a), the second type of STA can perform negotiation related to SP allocation with the first type of STA. For example, the second type of STA can request information necessary for allocating an SP to the first type of STA. In response to this, the first type of STA can calculate parameters / values related to the SP that needs to be allocated to it (i.e., the first type of STA) based on the information received from the third type of STA associated with it, and send the calculated result to the second type of STA. Alternatively, the first type of STA can also provide the calculation result to the second type of STA without a request from the second type of STA.

[0209] For example, the information requested by the second type of STA or provided by the first type of STA to the second type of STA can include at least one of the following information in the examples:

[0210] - Minimum SP interval: The minimum time interval between SPs requested by the first type of STA

[0211] - Maximum SP interval: The maximum time interval between SPs requested by the first type of STA

[0212] - Minimum SP duration: The minimum time length of an SP requested by the first type of STA

[0213] - Maximum SP duration: The maximum time length of an SP requested by the first type of STA

[0214] - SP start time: The start time of the SP requested by the first type of STA (e.g., the time offset compared to a predetermined reference time)

[0215] - Buffered data volume: The total amount of data buffered by the third type of STA associated with the first type of STA or buffered by the first type of STA (e.g., delay-sensitive data to be sent and received)

[0216] For example, a first type of STA 1 can obtain information T_A on the buffered data of a third type of STA A and information T_B on the buffered data of a third type of STA B. Instead of sending T_A and T_B to a second type of STA, STA 1 can calculate values of parameters such as minimum interval, maximum interval, minimum duration, maximum duration, start time, buffered data volume (e.g., the sum of T_A, T_B, and the buffered data of STA 1) for SP_1 based on T_A and T_B and provide them to the second type of STA. Similarly, the remaining first type of STA 2 or STA 3 can also calculate parameters for the requested SP_2 or SP_3 based on information T_C on the buffered data of a third type of STA C associated with it or information T_D, T_E, and T_F on the buffered data of STA D, STA E, and STA F and provide them to the second type of STA.

[0217] In Figure 14 In the example of (b), the second type of STA can schedule the SP for the first type of STA based on the parameters for the SP requested from the first type of STA. The second type of STA can provide information related to the SP assigned to the first type of STA to the first type of STA.

[0218] For example, the SP_1, SP_2, and SP_3 provided by the second type of STA can be included in one frame or element, or can be included in multiple frames or elements. Thus, one first type of STA can receive scheduling information assigned to at least one other first type of STA in addition to the scheduling information assigned to it.

[0219] For example, the SP allocation information provided by the second type of STA to the first type of STA can include at least one of the following information in the following examples:

[0220] - The number of first type of STAs: The number of first type of STAs to which the second type of STA allocates SPs

[0221] - Identification information of the first type of STA: The AP ID used to distinguish each first type of STA

[0222] - Information specific to the first type of STA (or information for each first type of STA): Information on the SPs assigned to each first type of STA

[0223] For example, the information specific to the first type of STA can be provided by using the TWT element format. For example, the information on the SP assigned to the corresponding first type of STA can be provided by the control field and the (individual or broadcast) TWT parameter set field included in the TWT element format.

[0224] Additionally or alternatively, a new SP information element including only information necessary to identify the SPs for the first type of STAs according to the present disclosure may be defined. The SP information element may include at least one piece of information in the following examples:

[0225] - Identification information of the first type of STA: The AP ID for distinguishing each first type of STA

[0226] - SP interval: The time interval between the SPs assigned to the first type of STA

[0227] - SP duration: The time length of the SP assigned to the first type of STA

[0228] - SP start time: The start time of the SP assigned to the first type of STA (e.g., the time offset compared to a predetermined reference time)

[0229] - Amount of buffered data: The total amount of data buffered by the third type of STA associated with the first type of STA or buffered by the first type of STA (e.g., time-sensitive data to be sent and received)

[0230] As in the above examples, the second type of STA may receive an SP allocation request from the first type of STA through a negotiation process and allocate SPs to the corresponding first type of STA based on the requested information. Additionally or alternatively, in the case where no SP allocation request is received from the first type of STA, the second type of STA may allocate SPs to the corresponding first type of STA based on the information about the first type of STA obtained in the previous process. For the case where there is an SP allocation request or no request from the first type of STA, the first type of STA may subsequently or additionally perform negotiation on the desired interval / length / start time, etc. by responding to accept or reject the interval / length / start time, etc. of the SPs allocated by the second type of STA.

[0231] Embodiment 2-2

[0232] In this embodiment, the characteristics of the SPs allocated by the second type of STA to multiple first type of STAs in the time domain are described according to the example of Embodiment 2-1.

[0233] Figure 15 is a diagram showing an example of the position of the SPs for the first type of STA according to the present disclosure in the time domain.

[0234] In Figure 15In the example of (a), SP_1, SP_2, and SP_3 that can respectively send and receive data with a third type of STA associated with each of the first type of STA 1, the first type of STA 2, and the first type of STA 3 can be allocated. Based on this, the first type of STA can schedule the third type of STA associated with each of them to send and receive data. For example, the lengths of SP_1, SP_2, and SP_3 can be the same or different. Since all the environments of each first type of STA are different, each first type of STA can adjust the length of the SP to be allocated through negotiation with the second type of STA.

[0235] In Figure 15 the example, frame exchange with the third type of STA can be periodically or cyclically performed within the corresponding SP in the order that the first type of STA 1 is allocated the longest SP, the first type of STA 2 is allocated the second longest SP, and the first type of STA 3 is allocated the shortest SP (i.e., in descending order of SP length). For example, SP_3 can start periodically or cyclically after SP_1 and SP_2. For example, the SPs for the first type of STA can be scheduled in a different order (e.g., in ascending order of SP length), and SPs of the same length for different first type of STAs can also be positioned in the time domain according to different criteria (e.g., in ascending or descending order of AP ID).

[0236] Within the SP of each first-type STA allocated by the second-type STA, data transmission and reception of the third-type STA associated with the corresponding first-type STA can have priority. In other words, during SP_1, only data transmission and reception between STA1 and STA A / STA B can be allowed, and during SP_2, only data transmission and reception between STA 2 and STA C can be allowed, and during SP_3, only data transmission and reception between STA 3 and STA D / STA E / STA F can be allowed. For this purpose, the second-type STA can limit data transmission and reception attempts of first-type STAs other than the corresponding first-type STA within the SP corresponding to each first-type STA. In addition, before the start of the SP of another first-type STA, the previous first-type STA can terminate data transmission and reception. For example, when STA 1 needs to transmit and receive data after SP_1 (i.e., when it fails to complete the required data transmission and reception within SP_1), data transmission and reception of the first-type STA 1 can be terminated for the SP_2 of STA 2 (i.e., before the start of SP_2). In this case, STA 1 can resume the remaining data transmission and reception in the next SP_1. For this purpose, the second-type STA can set a guard region (or guard time) between the SPs of each first-type STA. The guard region can be set in all or part of the SPs, or the guard region can be not set.

[0237] In Figure 15 In the example of (b), when C-SR or joint beamforming (or joint transmission) method is supported in multi-AP operation, all or part of the SPs allocated to different first-type STAs can overlap in the time domain. In the overlapping region, data transmission and reception of multiple first-type STAs and the STAs associated with them can be performed simultaneously, or data transmission and reception permission or priority can be granted only to one of the multiple first-type STAs. For example, the second-type STA can authorize data transmission priority only to one first-type STA based on information such as buffer data information of the first-type STA corresponding to the overlapping SP, the priority of the data to be transmitted, etc. The second-type STA can signal information indicating that one first-type STA has priority for the first-type STA, or can determine which first-type STA has priority for data transmission and reception in the overlapping region without separate signaling based on predefined rules. For example, for the region where SP_1 and SP_2 overlap, the second-type STA can compare information such as the priority of the buffer data volume / to-be-transmitted volume of STA 1 and STA2 to set only one first-type STA (e.g., STA1 or STA 2) to transmit and receive data with the third-type STA associated with it in the overlapping region.

[0238] In existing WLAN systems, a method is applied where the AP and STA attempt to access the wireless medium based on carrier sensing, or the AP provides scheduling information for uplink transmission from the STA to the AP by triggering, or the AP sets a time period for restricting the transmission of STAs other than a specific STA (e.g., SP based on r-TWT). In contrast, the scheduling method based on multi-AP operation according to an example of the present disclosure can efficiently support scheduling (e.g., SP allocation) for at least one first type of STA (e.g., shared AP or slave AP), a second type of STA (e.g., shared AP or master AP), and / or at least one third type of STA (e.g., non-AP STA). To this end, as in the example described above, the following new effects can be achieved: where the efficient scheduling based on multi-AP operation as described above is performed based on information exchanged through frame exchange (e.g., negotiation) on the wireless medium between at least one first type of STA and a second type of STA.

[0239] The above-described embodiments combine the elements and features of the present disclosure in a predetermined form. Unless otherwise explicitly mentioned, each element or feature should be considered optional. Each element or feature can be implemented in a form that does not combine with other elements or features. Additionally, the embodiments of the present disclosure can include combining some elements and / or features. The order of operations described in the embodiments of the present disclosure can be changed. Some elements or features of one embodiment can be included in other embodiments, or can be replaced by corresponding elements or features of other embodiments. Obviously, the embodiments can include combining claims that do not have an explicit citation relationship in the claims, or can be included as new claims through amendment after the application.

[0240] Those skilled in the relevant art will appreciate that the present disclosure can be implemented in other specific forms without departing from the essential features of the present disclosure. Therefore, the above detailed description should not be construed restrictively in every aspect, but should be considered illustrative. The scope of the present disclosure should be determined by a reasonable interpretation of the appended claims, and all changes within the equivalent scope of the present disclosure are included within the scope of the present disclosure.

[0241] The scope of the present disclosure includes software or machine-executable instructions (e.g., operating systems, applications, firmware, programs, etc.) that perform operations according to various embodiments in a device or computer, and non-transitory computer-readable media that cause the software or instructions, etc. to be stored and executable in the device or computer. The instructions that can be used to program a processing system to perform the features described in the present disclosure can be stored in a storage medium or computer-readable storage medium, and the features described in the present disclosure can be implemented by using a computer program product including such a storage medium. The storage medium can include high-speed random access memory, e.g., DRAM, SRAM, DDR RAM, or other random access solid-state storage devices, but is not limited thereto, and it can include non-volatile memory, e.g., one or more 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 remotely from the processor. The memory, or alternatively, the non-volatile memory device in the memory, includes non-transitory computer-readable storage medium. The features described in the present disclosure can be stored in any kind of machine-readable medium to control the hardware of the processing system, and can be integrated into software and / or firmware that allows the processing system to interact with other mechanisms using the results from the embodiments of the present disclosure. Such software or firmware can include application code, device drivers, operating systems, and execution environments / containers, but is not limited thereto.

[0242] Industrial Applicability

[0243] The method proposed in the present disclosure is mainly described based on examples applied to IEEE 802.11-based systems (5G systems), but can be applied to various WLAN or wireless communication systems other than IEEE 802.11-based systems.

Claims

1. A method performed by a first type of station STA in a Wireless Local Area Network (WLAN) system, the method comprising the steps of: receiving, from a second type of STA, information related to at least one Service Period (SP) for the first type of STA among a plurality of first type of STAs; and performing frame exchange with at least one third type of STA associated with the first type of STA, based on the information related to the at least one SP, wherein the at least one SP includes an SP that restricts STAs other than the first type of STA and the at least one third type of STA from transmitting, wherein the information related to the at least one SP further includes information about at least one other SP that allows at least one of at least one other first type of STA among the plurality of first type of STAs or at least one other third type of STA associated with the at least one other first type of STA to transmit.

2. The method according to claim 1, wherein the at least one SP is set by the second type of STA based on information provided to the second type of STA from the first type of STA and information provided to the second type of STA from the at least one other first type of STA, the information provided to the second type of STA includes information provided to the first type of STA from the at least one third type of STA and information provided to the at least one other first type of STA from the at least one other third type of STA.

3. The method according to claim 2, wherein the information related to the at least one SP includes information indicating the at least one SP set by the second type of STA, the information indicating the at least one SP set by the second type of STA is provided from the first type of STA to the at least one third type of STA.

4. The method according to claim 1, wherein the at least one SP is determined by the first type of STA based on the information related to the at least one SP, information indicating the at least one SP determined by the first type of STA is provided from the first type of STA to the at least one third type of STA.

5. The method according to claim 4, wherein the information related to the at least one SP includes at least one of the following: the number of the plurality of first type of STAs, identification information about each first type of STA among the plurality of first type of STAs, or information about the SPs assigned to each first type of STA among the plurality of first type of STAs.

6. The method according to claim 5, wherein the information about the SPs assigned to each first type of STA among the plurality of first type of STAs includes at least one of the following: identification information of the corresponding first type of STA; or information about at least one of the interval, duration, or start time of the assigned SP.

7. The method according to claim 4, wherein The information related to the at least one SP is set by the second type of STA based on information provided to the second type of STA from at least one first type of STA among the multiple first type of STAs.

8. The method according to claim 7, wherein, the information provided to the second type of STA from at least one first type of STA among the multiple first type of STAs is based on information received by the corresponding first type of STA from at least one third type of STA associated with the corresponding first type of STA.

9. The method according to claim 7, wherein, the information provided to the second type of STA from at least one first type of STA among the multiple first type of STAs includes at least one of the following: information about at least one of a minimum interval, a maximum interval, a minimum duration, a maximum duration, or a start time of an SP requested by the corresponding first type of STA; or information about the total amount of data buffered in the corresponding first type of STA and at least one third type of STA associated with the corresponding first type of STA.

10. The method according to claim 7, wherein, in response to a request from the second type of STA or in the absence of a request from the second type of AP, the information provided to the second type of STA from at least one first type of STA among the multiple first type of STAs is provided to the second type of STA.

11. The method according to claim 4, wherein, based on a request from at least one first type of STA among the multiple first type of STAs, the information related to the at least one SP is provided to the multiple first type of STAs.

12. The method according to claim 4, wherein, for the information related to the at least one SP, information indicating acceptance or rejection from each first type of STA among the multiple first type of STAs is sent to the second type of STA.

13. The method according to claim 1, wherein, the at least one SP corresponding to the first type of STA and at least one other SP corresponding to at least one other first type of STA do not overlap in the time domain.

14. The method according to claim 1, wherein, the at least one SP corresponding to the first type of STA and at least one other SP corresponding to at least one other first type of STA include an overlapping region in the time domain.

15. The method according to claim 14, wherein, based on a predetermined rule, a first type of STA among the first type of STA and the at least one other first type of STA having priority for transmission and reception in the overlapping region is determined, or information indicating the first type of STA having the priority for the transmission and the reception is signaled by the second type of STA.

16. The method according to claim 1, wherein, the first type and the second type correspond to an access point AP, The third type corresponds to a non-AP STA.

17. The method according to claim 1, wherein, the first type corresponds to a shared AP, the second type corresponds to a sharing AP, the third type corresponds to a non-AP STA associated with the shared AP.

18. A first type of station STA device in a wireless local area network WLAN system, the first type of station STA device comprises: at least one transceiver; and at least one processor connected to the at least one transceiver, wherein the at least one processor is configured to: receive, via the at least one transceiver, information related to at least one service period SP for the first type of STA among a plurality of first type of STAs from a second type of STA; and perform frame exchange with at least one third type of STA associated with the first type of STA via the at least one transceiver based on the information related to the at least one SP, wherein the at least one SP includes an SP that restricts STAs other than the first type of STA and the at least one third type of STA from transmitting, wherein the information related to the at least one SP further includes information about at least one other SP that allows at least one of at least one other first type of STA among the plurality of first type of STAs or at least one other third type of STA associated with the at least one other first type of STA to transmit.

19. A method performed by a second type of station STA in a wireless local area network WLAN system, the method comprises the following steps: setting information related to at least one service period SP based on information provided by a plurality of first type of STAs; and and sending the information related to the at least one SP to the plurality of first type of STAs, wherein the at least one SP includes an SP that restricts STAs other than the first type of STA among the plurality of first type of STAs and at least one third type of STA associated with the first type of STA from transmitting, wherein the information related to the at least one SP further includes information about at least one other SP that allows at least one of at least one other first type of STA among the plurality of first type of STAs or at least one other third type of STA associated with the at least one other first type of STA to transmit.

20. A second type of station STA device in a wireless local area network WLAN system, the second type of station STA device comprises: at least one transceiver; and at least one processor connected to the at least one transceiver, wherein the at least one processor is configured to: set information related to at least one service period SP based on information provided by a plurality of first type of STAs; and send the information related to the at least one SP to the plurality of first type of STAs via the at least one transceiver, Wherein, the at least one SP includes an SP that restricts STAs other than the first type STA among the plurality of first type STAs and at least one third type STA associated with the first type STA from transmitting. Wherein, the information related to the at least one SP further includes information about at least one other SP, and the at least one other SP allows at least one of at least one other first type STA among the plurality of first type STAs or at least one other third type STA associated with the at least one other first type STA to transmit.

21. A processing device configured to control a station STA in a wireless local area network WLAN system, the processing device comprising: at least one processor; and at least one computer memory operatively connected to the at least one processor, the at least one computer memory storing instructions for performing the method according to claim 1 when executed by the at least one processor.

22. At least one non-transitory computer-readable medium storing at least one instruction, wherein, the at least one instruction controls a device to perform the method according to claim 1 in a wireless local area network WLAN system when executed by at least one processor.

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