Signaling method and apparatus based on multi-access point operation in wireless LAN system

Abstract

Disclosed are an operation method and apparatus in a wireless LAN system. A method performed by means of a first AP in a wireless LAN system according to one embodiment of the present disclosure comprises the steps of: receiving an MU RTS TXS trigger frame from a second AP; and transmitting a DL PPDU or a first trigger frame to the one or more STAs based on the MU-RTS TXS trigger frame, in which the MU-RTS TXS trigger frame may include first information for indicating a TXOP allocation related to the multi-AP operation and second information related to the first AP.

Description

TECHNICAL FIELD

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

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

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

[0004] TECHNICAL PROBLEM

[0005] The technical problem of the disclosure is to provide a method and apparatus for signaling based on multi-access point (AP) operation in a wireless LAN system.

[0006] The technical problem of the disclosure is to provide a method of triggering a multi-AP operation by a representative AP in a wireless LAN system.

[0007] The technical objects to be achieved by the disclosure are not limited to the aforementioned technical objects and other technical objects not described herein will be clearly understood by a person skilled in the art from the following description.

[0008] TECHNICAL SOLUTION

[0009] According to one embodiment of the disclosure, a method performed by a first access point (AP) in a wireless LAN system can include the steps of: receiving a multi-user (MU) request-to-send (RTS) transmission opportunity sharing (TXS) trigger frame from a second AP; transmitting a downlink (DL) physical layer protocol data unit (PPDU) or a first trigger frame to at least one STA based on the MU-RTS TXS trigger frame, and the MU-RTS TXS trigger frame can include first information indicating that the MU-RTS TXS trigger frame is allocated for a transmission opportunity (TXOP) related to a multi-AP operation and second information related to the first AP.

[0010] According to another embodiment of the disclosure, a method performed by a second access point (AP) in a wireless LAN system can include the steps of: transmitting a multi-user (MU) request-to-send (RTS) transmission opportunity sharing (TXS) trigger frame to a first AP; and receiving data transmission and reception result information between at least one STA from the first AP, and based on the MU-RTS TXS trigger frame, a downlink (DL) physical layer protocol data unit (PPDU) or a first trigger frame can be transmitted from the first AP to the at least one STA, and the MU-RTS TXS trigger frame can include first information indicating that the MU-RTS TXS trigger frame is allocated for a transmission opportunity (TXOP) related to a multi-AP operation and second information related to the first AP.

[0011] Technical Effects

[0012] According to various embodiments of the disclosure, a method and apparatus for signaling based on multi-access point (AP) operation in a wireless LAN system can be provided.

[0013] According to various embodiments of the disclosure, a method of triggering a multi-AP operation by a representative AP in a wireless LAN system can be provided.

[0014] According to various embodiments of the disclosure, by triggering a multi-AP operation, more efficient resource utilization can be achieved.

[0015] Effects that can be achieved by the disclosure are not limited to the above-mentioned effects, and other effects not described herein can be clearly understood by those skilled in the art from the following description. BRIEF DESCRIPTION OF DRAWINGS

[0016] The accompanying drawings, which are included as part of the specific embodiments for understanding the disclosure, provide embodiments of the disclosure and, together with the specific embodiments, describe the technical features of the disclosure.

[0017] Figure 1 A configuration block diagram of a wireless communication apparatus according to an embodiment of the disclosure is illustrated.

[0018] Figure 2 FIG. 1 is a diagram illustrating an exemplary structure of a WLAN system to which the disclosure can be applied.

[0019] Figure 3 FIG. 2 is a diagram for explaining a link setup process to which the disclosure can be applied.

[0020] Figure 4 FIG. 3 is a diagram for explaining a backoff process to which the disclosure can be applied.

[0021] Figure 5 FIG. 4 is a diagram for explaining a CSMA / CA-based frame transmission operation to which the disclosure can be applied.

[0022] Figure 6 FIG. 5 is a diagram for explaining an example of a frame structure used in a WLAN system to which the disclosure can be applied.

[0023] Figure 7 FIG. 6 is a diagram illustrating an example of a PPDU defined in an IEEE 802.11 standard to which the disclosure can be applied.

[0024] Figure 8 FIG. 7 illustrates an exemplary format of a trigger frame to which the disclosure can be applied.

[0025] Figure 9 FIG. 8 is a diagram for explaining operations performed by a first AP according to an embodiment of the disclosure.

[0026] Figure 10 FIG. 9 is a diagram for explaining operations performed by a second AP according to an embodiment of the disclosure. DETAILED DESCRIPTION

[0027] Hereinafter, embodiments according to the disclosure will be described in detail with reference to the accompanying drawings. The detailed description disclosed by the accompanying drawings is to describe exemplary embodiments of the disclosure and is not intended to represent the only embodiments in which the disclosure can be implemented. The following detailed description includes specific details to provide a thorough understanding of the disclosure. However, it will be apparent to those skilled in the art that the disclosure can be practiced without these specific details.

[0028] In some cases, known structures and devices can be omitted or can be shown in the form of block diagrams in order to prevent a concept of the disclosure from being obscured.

[0029] In the disclosure, when an element is referred to as being "connected", "combined", or "linked" to another element, it can include an indirect connection relationship between the other element and a further element existing therebetween as well as a direct connection relationship. Also, in the disclosure, the term "comprising" or "having" specifies the existence of the mentioned features, steps, operations, components, and / or elements, but does not exclude the existence or addition of one or more other features, stages, operations, components, elements, and / or groups thereof.

[0030] In the disclosure, the terms such as "first", "second", and the like are used only to distinguish one element from another element and not to limit the elements, unless otherwise specified, and do not limit the order or importance between the elements, etc. Therefore, within the scope of the disclosure, a first element in an embodiment can be referred to as a second element in another embodiment, and likewise, a second element in an embodiment can be referred to as a first element in another embodiment.

[0031] The terms used in the disclosure are for the purpose of describing specific embodiments, not limiting the claims. As used in the description of embodiments and the appended claims, the singular forms are intended to include the plural forms, unless the context clearly dictates otherwise. The term "and / or" used in the disclosure can refer to one of the related listed items, or mean that it refers to and includes any and all possible combinations of two or more of them. In addition, unless otherwise specified, " / " between words in the disclosure has the same meaning as "and / or".

[0032] Examples of the disclosure can be applied to various wireless communication systems. For example, examples of the disclosure can be applied to a wireless LAN system. For example, examples of the disclosure can be applied to a wireless LAN based on IEEE 802.11a / g / n / ac / ax standards. In addition, examples of the disclosure can be applied to a wireless LAN based on a newly proposed IEEE 802.11be (or EHT) standard. Examples of the disclosure can be applied to a wireless LAN based on an IEEE 802.11be version 2 standard corresponding to additional enhancement technologies of the IEEE 802.11be version 1 standard. In addition, examples of the disclosure can be applied to a wireless LAN based on a next-generation standard after the IEEE 802.11be. Furthermore, examples of the disclosure can be applied to a cellular wireless communication system. For example, it can be applied to a cellular wireless communication system based on Long Term Evolution (LTE) based technology based on the Third Generation Partnership Project (3GPP) standard and 5G New Radio (NR) technology.

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

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

[0035] Figure 1 The first and second devices 100 and 200 exemplified in the middle 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, etc. In addition, the first and second devices 100 and 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 road side unit (RSU), a repeater, a router, a relay, and a gateway.

[0036] Figure 1 The devices 100 and 200 exemplified in the middle can be referred to as a station (STA). For example, Figure 1 The devices 100 and 200 exemplified in the middle can be referred to with various terms such as a transmitting device, a receiving device, a transmitting STA, and a receiving STA. For example, the STAs 110 and 200 can perform an access point (AP) role or a non-AP role. That is, in the present disclosure, the STAs 110 and 200 can perform the functions of the AP and / or the non-AP. When the STAs 110 and 200 perform the AP function, they can be simply referred to as an AP, and when the STAs 110 and 200 perform the non-AP function, they can be simply referred to as a STA. In addition, in the present disclosure, the AP can also be indicated as an AP STA.

[0037] Referring to Figure 1 The first and second devices 100 and 200 can transmit and receive radio signals through various wireless LAN technologies (for example, IEEE 802.11 series). The first and second devices 100 and 200 can include an interface for a medium access control (MAC) layer and a physical layer (PHY) to comply with the IEEE 802.11 standard.

[0038] In addition, the first and second devices 100 and 200 can additionally support various communication standard (for example, 3GPP LTE series, 5G NR series standards, etc.) technologies in addition to the wireless LAN technology. In addition, the devices of the present disclosure can be implemented in various devices such as a mobile phone, a vehicle, a personal computer, an augmented reality (AR) device, and a virtual reality (VR) device, etc. In addition, the STAs of the present specification can support various communication services such as a voice call, a video call, data communication, autonomous driving, machine type communication (MTC), machine to machine (M2M), device to device (D2D), IoT (Internet of Things), etc.

[0039] The first apparatus 100 can include one or more processors 102 and one or more memories 104, and can additionally include one or more transceivers 106 and / or one or more antennas 108. The processor 102 can control the memory 104 and / or the transceiver 106, and can be configured to implement descriptions, functions, procedures, suggestions, methods and / or operational flowcharts included in the present disclosure. For example, the processor 102 can generate first information / signal by processing information in the memory 104, and then transmit a wireless signal including the first information / signal through the transceiver 106. Also, the processor 102 can receive a wireless signal including second information / signal through the transceiver 106, and then store information obtained by signal processing of the second information / signal in the memory 104. The memory 104 can be connected to the processor 102 and can store a variety of information related to operations of the processor 102. For example, the memory 104 can store software code including instructions for performing all or a part of processes controlled by the processor 102 or for performing descriptions, functions, procedures, suggestions, methods and / or operational flowcharts included in the present disclosure. Here, the processor 102 and the memory 104 can be a part of a communication modem / circuit / chip designed to implement a wireless LAN technology (e.g., IEEE 802.11 series). The transceiver 106 can be connected to the processor 102 and can transmit and / or receive a wireless signal through the one or more antennas 108. The transceiver 106 can include a transmitter and / or a receiver. The transceiver 106 can be used together with an RF (Radio Frequency) unit. In the present disclosure, a wireless apparatus can mean a communication modem / circuit / chip.

[0040] The second device 200 can include one or more processors 202 and one or more memories 204, and can additionally include one or more transceivers 206 and / or one or more antennas 208. The processor 202 can control the memory 204 and / or the transceiver 206, and can be configured to implement descriptions, functions, procedures, suggestions, methods and / or operational flowcharts included in the present disclosure. For example, the processor 202 can generate third information / signal by processing information in the memory 204, and then transmit a wireless signal including the third information / signal through the transceiver 206. In addition, the processor 202 can receive a wireless signal including fourth information / signal through the transceiver 206, and then store information obtained by signal processing through the fourth information / signal in the memory 204. The memory 204 can be connected to the processor 202 and can store a variety of information related to operations of the processor 202. For example, the memory 204 can store software code including instructions for performing all or part of processes controlled by the processor 202 or for performing descriptions, functions, procedures, suggestions, methods and / or operational flowcharts included in the present disclosure. Here, the processor 202 and the memory 204 can be part of a communication modem / circuit / chip designed to implement a wireless LAN technology (e.g., IEEE 802.11 series). The transceiver 206 can be connected to the processor 202 and can transmit and / or receive a wireless signal through the one or more antennas 208. The transceiver 206 can include a transmitter and / or a receiver. The transceiver 206 can be used together with an RF unit. In the present disclosure, a device can mean a communication modem / circuit / chip.

[0041] Hereinafter, the hardware elements of the apparatuses 100, 200 will be described in more detail. Without limitation, one or more protocol layers can be implemented by the one or more processors 102, 202. For example, the one or more processors 102, 202 can implement one or more layers (e.g., functional layers such as PHY, MAC). The one or more processors 102, 202 can 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 operational flowcharts disclosed in the present disclosure. The one or more processors 102, 202 can generate messages, control information, data, or information according to the descriptions, functions, procedures, suggestions, methods, and / or operational flowcharts disclosed in the present disclosure. The one or more processors 102, 202 can generate signals (e.g., baseband signals) including the PDUs, SDUs, messages, control information, data, or information according to the functions, procedures, suggestions, and / or methods disclosed in the present disclosure to provide the same to the one or more transceivers 106, 206. The one or more processors 102, 202 can receive signals (e.g., baseband signals) from the one or more transceivers 106, 206 according to the descriptions, functions, procedures, suggestions, methods, and / or operational flowcharts included in the present disclosure, and obtain the PDUs, SDUs, messages, control information, data, or information.

[0042] The one or more processors 102, 202 can be referred to as controllers, microcontrollers, microprocessors, or microcomputers. The one or more processors 102, 202 can 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 Processors Devices), one or more PLDs (Programmable Logic Devices), or one or more FPGAs (Field Programmable Gate Arrays) can be included in the one or more processors 102, 202. The descriptions, functions, procedures, suggestions, methods, and / or operational flowcharts included in the present disclosure can be implemented by using firmware or software, and the firmware or software can be implemented as including modules, procedures, functions, etc. The firmware or software configured to perform the descriptions, functions, procedures, suggestions, methods, and / or operational flowcharts included in the present disclosure can be included in the one or more processors 102, 202, or can be stored in the one or more memories 104, 204 and driven by the one or more processors 102, 202. The descriptions, functions, procedures, suggestions, methods, and / or operational flowcharts included in the present disclosure can be implemented by using firmware or software in the form of codes, instructions, and / or instruction sets.

[0043] One or more memories 104, 204 can be connected to one or more processors 102, 202 and can store data, signals, messages, information, programs, codes, instructions, and / or commands in various forms. One or more memories 104, 204 can be configured with ROM, RAM, EPROM, flash memory, hard drives, registers, cache memories, computer-readable storage media, and / or combinations thereof. One or more memories 104, 204 can be located internal and / or external to one or more processors 102, 202. In addition, one or more memories 104, 204 can be connected to one or more processors 102, 202 by various technologies such as wired or wireless connections.

[0044] The one or more transceivers 106, 206 can transmit user data, control information, wireless signals / channels, etc. mentioned in the methods and / or operational flowcharts, etc. of the disclosure to one or more other apparatuses. The one or more transceivers 106, 206 can receive user data, control information, wireless signals / channels, etc. mentioned in the descriptions, functions, processes, suggestions, methods and / or operational flowcharts, etc. included in the disclosure from one or more other apparatuses. For example, the one or more transceivers 106, 206 can be connected to the one or more processors 102, 202 and can transmit and receive wireless signals. For example, the one or more processors 102, 202 can control the one or more transceivers 106, 206 to transmit user data, control information, or wireless signals to one or more other apparatuses. In addition, the one or more processors 102, 202 can control the one or more transceivers 106, 206 to receive user data, control information, or wireless signals from one or more other apparatuses. In addition, the one or more transceivers 106, 206 can be connected to the one or more antennas 108, 208, and the one or more transceivers 106, 206 can be configured to transmit and receive user data, control information, wireless signals / channels, etc. mentioned in the descriptions, functions, processes, suggestions, methods and / or operational flowcharts, etc. included in the disclosure through the one or more antennas 108, 208. In the disclosure, the one or more antennas can be a plurality of physical antennas or a plurality of logical antennas (for example, antenna ports). The one or more transceivers 106, 206 can convert received wireless signals / channels, etc. from RF band signals to baseband signals to process received user data, control information, wireless signals / channels, etc. by using the one or more processors 102, 202. The one or more transceivers 106, 206 can convert user data, control information, wireless signals / channels, etc. processed by using the one or more processors 102, 202 from baseband signals to RF band signals. Accordingly, the one or more transceivers 106, 206 can include (analog) oscillators and / or filters.

[0045] For example, one of the STAs 100 and 200 can perform the intended operation of an AP, and the other of the STAs 100 and 200 can perform the intended operation of a non-AP STA. For example, Figure 1 The transceivers 106 and 206 of the STA 100 and 200 can perform transmission and reception operations of signals (for example, packets or physical layer protocol data units (PPDUs) conforming to IEEE 802.11a / b / g / n / ac / ax / be / bn). In addition, in the disclosure, operations in which various STAs generate transmission / reception signals or perform data processing or calculation in advance for transmission / reception signals can be performed by the one or more processors 102, 202. Figure 1The operations of generating a transmission / reception signal or performing data processing or calculation in advance for the operations of the transmission / reception signal can include, for example, 1) determining / acquiring / configuring / calculating / decoding / encoding bit information of a field (a signal (SIG), a short training field (STF), a long training field (LTF), data, etc.) included in a PPDU, 2) determining / configuring / acquiring a time resource or a frequency resource (e.g., a subcarrier resource) for a field (a SIG, an STF, an 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 a SIG) for a field (a SIG, an STF, an LTF, data, etc.) included in a PPDU action, 4) a power control operation and / or a power saving operation applied to a STA, 5) an operation related to an ACK signal determination / acquisition / configuration / calculation / decoding / encoding, etc. In addition, in the following examples, various information (e.g., information related to a field / subfield / control field / parameter / power, etc.) used by various STAs to determine / acquire / configure / calculate / decode / encode a transmission signal and a reception signal can be stored in the memories 104 and 204 of the processors 102 and 202. Figure 1

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

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

[0048] The structure of the wireless LAN system can be composed of a plurality of components. The wireless LAN supporting mobility transparent to an upper layer can be provided through the interaction of the plurality of components. A basic service set (BSS) corresponds to a basic building block of the wireless LAN. Figure 2 Exemplarily, it is shown that there are two BSSs (BSS1 and BSS2), and two STAs (STA1 and STA2 are included in BSS1, and STA3 and STA4 are included in BSS2) are included as members of each BSS. Figure 2 ​The ellipse representing the BSS can also be interpreted as representing the coverage area within the corresponding BSS where STAs maintain communication. This area can be called the Basic Service Area (BSA). When a STA moves outside the BSA, it cannot communicate directly with other STAs within the BSA.

[0049] If we do not consider Figure 2 The DS shown in the diagram represents the most basic BSS type in a wireless LAN: the Independent BSS (IBSS). For example, an IBSS can have a minimal form containing only two STAs. For instance, assuming other components are omitted, BSS1 containing only STA1 and STA2, or BSS2 containing only STA3 and STA4, can respectively correspond to representative examples of IBSS. This configuration is possible when STAs can communicate directly without an AP. Furthermore, in this type of wireless LAN, it is not pre-configured but can be configured as needed, and this can be called an ad-hoc network. Since an IBSS does not include an AP, there is no centralized management entity. That is, in an IBSS, STAs are managed in a distributed manner. In an IBSS, all STAs can consist of mobile STAs and are not allowed to access the Distributed System (DS), thus forming a self-contained network.

[0050] Membership of an STA in a BSS can be dynamically changed by opening or closing an STA, or by entering or leaving a BSS zone. To become a member of a BSS, an STA can join the BSS using a synchronization process. To access all services of the BSS infrastructure, an STA must be associated with the BSS. This association can be dynamically established and may include the use of Distributed System Services (DSS).

[0051] Direct STA-to-STA distance in a wireless LAN may be limited by PHY performance. In some cases, this distance limitation may be sufficient, but in others, longer distances between STAs may be required for communication. Distributed systems (DS) can be configured to support extended coverage.

[0052] DS refers to the structure of BSS interconnection. Specifically, such as... Figure 2As shown, a BSS can exist as an extension of a network composed of multiple BSSs. A DS is a logical concept and can be specified through the characteristics of the Distributed System Medium (DSM). At this point, the Wireless Medium (WM) and the DSM can be logically separated. Each logical medium is used for a different purpose and by different components. These media are not limited to being the same, nor are they limited to being different. In this way, the flexibility of a wireless LAN architecture (DS architecture or other network architectures) can be interpreted as multiple media being logically different. That is, a wireless LAN architecture can be implemented in various ways, and the corresponding wireless LAN architecture can be independently specified by the physical characteristics of each implementation.

[0053] The DS can support mobile devices by providing seamless integration of multiple BSSs and offering the logical services necessary for addressing to the destination. Additionally, the DS may include a component called a portal, which acts as a bridge between the wireless LAN and other networks (e.g., IEEE 802.X).

[0054] AP enables access to DS via WM for associated non-AP STAs, and refers to entities that also have STA functionality. Data movement between BSS and DS can be performed through AP. For example, Figure 2 STA2 and STA3, shown in the diagram, have the functionality of STAs and provide the ability for associated non-AP STAs (STA1 and STA4) to access the DS. Furthermore, since all APs essentially correspond to STAs, all APs are addressable entities. The address used by an AP for communication on the WM is not necessarily the same as the address used by the AP for communication on the DSM. A BSS consisting of APs and one or more STAs can be referred to as an infrastructure BSS.

[0055] Data sent from one of the STAs associated with the AP to the corresponding STA address of the AP can always be received on an uncontrolled port and can be processed by the IEEE 802.1X port access entity. Alternatively, when the controlled port is authenticated, the transmitted data (or frames) can be delivered to the DS.

[0056] In addition to the DS structure described above, Extended Service Sets (ESS) can also be configured to provide wide coverage.

[0057] An ESS (Service Set Identity) refers to a network of arbitrary size and complexity consisting of DS (Service Controller) and BSS (Service Set Service). An ESS can correspond to a set of BSSs connected to a DS. However, an ESS does not include the DS. An ESS network is characterized as an IBSS (Integrated Service Set Service) within the Logical Link Control (LLC) layer. STAs included in an ESS can communicate with each other, and a moving STA can transparently move from one BSS to another (within the same ESS) to the LLC. APs included in an ESS can have the same Service Set Identity (SSID). The SSID is distinguished from the BSSID, which serves as the identifier for the BSS.

[0058] Wireless LAN systems make no assumptions about the relative physical locations of BSSs, and all of the following forms are possible: BSSs can partially overlap, which is commonly used to provide continuous coverage. Additionally, BSSs may not be physically connected, and logically, there is no limit to the distance between BSSs. Furthermore, BSSs can be physically located in the same location, which can be used to provide redundancy. Additionally, one (or more) IBSS or ESS networks can physically exist in the same space as one (or more) ESS networks. This can correspond to the form of ESS networks when an ad hoc network operates in a location where an ESS network exists, when physically overlapping wireless networks are configured by different organizations, or when two or more different access and security policies are required in the same location, etc.

[0059] Figure 3 This is a diagram illustrating the link establishment process that can be applied to this disclosure.

[0060] In order for a STA to establish a link with the network and send / receive data, it first discovers the network, performs authentication, establishes an association, and performs authentication processing for security. The link establishment process can also be called session initiation processing or session establishment processing. Furthermore, the discovery, authentication, association, and security establishment processes of the link establishment process can be collectively referred to as association processing.

[0061] In step S310, the STA can perform a network discovery operation. The network discovery operation may include a scanning operation by the STA. That is, in order for the STA to access a network, it needs to find networks it can participate in. The STA should identify compatible networks before participating in a wireless network, and the process of identifying networks existing in a specific area is called scanning.

[0062] Scanning schemes include active scanning and passive scanning. Figure 3An exemplary network discovery operation including active scanning is illustrated. In active scanning, the STA performing the scan sends a probe request frame to discover which APs are present around it as the channel moves and awaits a response. The responder sends a probe response frame as a response to the probe request frame to the STA that sent the probe request frame. Here, the responder may be the STA that last sent a beacon frame in the BSS of the channel being scanned. In the BSS, the AP becomes the responder because it sends a beacon frame, and in the IBSS, the STAs in the IBSS rotate to send beacon frames, so the responder is not constant. For example, an STA that sends a probe request frame on channel 1 and receives a probe response frame on channel 1 may store the BSS-related information included in the received probe response frame and may move to the next channel (e.g., channel 2) and perform a scan in the same manner (i.e., sending and receiving probe requests / responses on channel 2).

[0063] Although not in Figure 3 As shown, scanning can be performed passively. In passive scanning, the STA performing the scan waits for beacon frames while moving through the channel. Beacon frames are one of the management frames defined in IEEE 802.11 and are sent periodically to notify of the existence of a wireless network and allow the STA performing the scan to find and participate in the wireless network. In the BSS, the AP periodically sends beacon frames, and in the IBSS, the STA within the IBSS rotates to send beacon frames. When the STA performing the scan receives a beacon frame, it stores the BSS information included in the beacon frame and records the beacon frame information for each channel while moving to another channel. The STA receiving the beacon frame can store the BSS-related information included in the received beacon frame, move to the next channel, and perform scanning in the next channel in the same manner. Comparing active and passive scanning, active scanning has the advantages of less latency and less power consumption.

[0064] After the STA discovers the network, an authentication process can be performed in step S320. To clearly distinguish it from the security establishment operation in step S340, which will be described later, this authentication process can be referred to as the first authentication process.

[0065] The authentication process includes the following steps: the STA sends an authentication request frame to the AP, and in response, the AP sends an authentication response frame to the STA. The authentication frame used for the authentication request / response corresponds to the management frame.

[0066] An authentication frame includes the authentication algorithm number, authentication transaction sequence number, status code, challenge text, robust security network (RSN), and finite circular group. These correspond to some examples of information that can be included in the authentication request / response frame and can be replaced with other information, or additional information may be included.

[0067] A STA can send an authentication request frame to an AP. The AP can determine whether to allow the corresponding STA's authentication based on the information included in the received authentication request frame. The AP can then provide the STA with the authentication processing result via an authentication response frame.

[0068] After the STA is successfully authenticated, the association process can be performed in step S330. The association process includes the following steps: the STA sends an association request frame to the AP, and in response, the AP sends an association response frame to the STA.

[0069] For example, an association request frame may include information related to various capabilities, beacon listening intervals, service set identifiers (SSIDs), supported rates, supported channels, RSNs, mobile domains, supported operation classes, service indication mapping broadcast requests (TIM broadcast requests), interoperability capabilities, etc. Similarly, an association response frame may include information related to various capabilities, status codes, association IDs (AIDs), supported rates, enhanced distributed channel access (EDCA) parameter sets, received channel power indicators (RCPIs), received signal-to-noise ratio indicators (RSNIs), mobile domains, timeout intervals (e.g., association recovery time), overlapping BSS scan parameters, TIM broadcast responses, quality of service (QoS) mappings, etc. These correspond to some examples of information that can be included in association request / response frames and may be replaced with other information, or additional information may be included.

[0070] After the STA successfully associates with the network, a security establishment process can be performed in step S340. The security establishment process in step S340 can be referred to as the authentication process via a Robust Secure Network Association (RSNA) request / response, the authentication process in step S320 is referred to as the first authentication process, and the security establishment process in step S340 can also be simply referred to as the authentication process.

[0071] The secure establishment process in step S340 may include, for example, the process of establishing a private key using a four-way handshake via Extensible Authentication Protocol (EAPOL) frames over the LAN. Alternatively, the secure establishment process may be performed according to a security scheme not defined in the IEEE 802.11 standard.

[0072] Figure 4 This is a diagram illustrating the fallback process that can be applied to this disclosure.

[0073] In wireless LAN systems, the basic access mechanism for Media Access Control (MAC) is Carrier Sensing Multiple Access with Collision Avoidance (CSMA / CA). Also known as the Distributed Coordination Function (DCF) of IEEE 802.11 MAC, CSMA / CA essentially employs a "listen-before-talk" access mechanism. Under this type of access mechanism, before commencing transmission, the AP and / or STA can perform explicit channel assessment (CCA) of the sensing radio channel or medium during a predetermined time interval (e.g., the DCF inter-frame interval (DIFS)). As a result of the sensing, if it is determined that the medium is idle, frame transmission begins via the corresponding medium. Conversely, if the medium is detected to be occupied or busy, the corresponding AP and / or STA does not begin its own transmission and can set a delay period for medium access (e.g., a random backoff period) and attempt frame transmission after waiting. By applying a random backoff period, collisions can be minimized because multiple STAs are expected to attempt frame transmission after waiting for different time periods.

[0074] In addition, the IEEE 802.11 MAC protocol provides a Hybrid Coordination Function (HCF). HCF is based on DCF and Point Coordination Function (PCF). PCF is a polling-based synchronous access method, meaning that all receiving APs and / or STAs periodically poll to receive data frames. Furthermore, HCF includes Enhanced Distributed Channel Access (EDCA) and HCF Control Channel Access (HCCA). EDCA is a contention-based access method that provides data frames to multiple users, while HCCA uses a non-contention-based channel access method that utilizes a polling mechanism. Additionally, HCF includes a media access mechanism for improving the QoS (Quality of Service) of wireless LANs and can transmit QoS data during contention periods (CP) and contention-free periods (CFP).

[0075] Reference Figure 4This section describes the operation based on a random backoff period. When an occupied / busy medium becomes idle, multiple STAs can attempt to transmit data (or frames). As a method to minimize collisions, each STA can individually select a random backoff count and attempt to transmit after waiting for the corresponding time slot. The random backoff count has a pseudo-random integer value and can be determined as one of the values ​​ranging from 0 to CW. Here, CW is the contention window parameter value. The CW parameter is assigned an initial value of CWmin, but can take a value twice as large as in the event of transmission failure (e.g., when no ACK is received for the transmitted frame). When the CW parameter value reaches CWmax, data transmission can be attempted while maintaining the CWmax value until successful data transmission, and when successful, the CWmin value is reset. The values ​​of CW, CWmin, and CWmax are preferably set to 2n-1 (n = 0, 1, 2, ...).

[0076] When random backoff processing begins, the STA continuously monitors the medium during the backoff time slot countdown based on the determined backoff count value. When monitoring the medium for occupancy, it stops the countdown and waits, and restarts the remainder of the countdown when the medium becomes idle.

[0077] exist Figure 4 In the example, when the packet to be sent arrives at STA 3's MAC, STA 3 can send the frame immediately after confirming that the medium has been idle for up to DIFS. The remaining STAs monitor and wait for the medium to be occupied / busy. Meanwhile, the data to be sent can also occur in each of STA 1, STA 2, and STA 5, and when the medium is detected as idle, each STA waits for up to DIFS, and then performs a countdown for the backoff slot based on a random backoff count value chosen by each STA. Assume STA 2 chooses the minimum backoff count value, and STA 1 chooses the maximum backoff count value. That is, the example illustrates the case where STA 5's remaining backoff time is shorter than STA 1's remaining backoff time when STA 2 completes its backoff count and begins frame transmission. STA 1 and STA 5 temporarily stop the countdown and wait while STA 2 occupies the medium. When STA 2's occupancy ends and the medium becomes idle again, STA 1 and STA 5 wait for DIFS and restart the stopped backoff count. In other words, frame transmission can begin after a countdown for the remaining backoff slot based on the remaining backoff time. Since STA5 has a shorter remaining backoff time than STA1, STA5 begins frame transmission. Data to be transmitted can also occur in STA4 while STA2 is occupying the medium. From STA4's perspective, when the medium becomes idle, STA4 can wait for DIFS, then execute a countdown based on a random backoff count value selected by STA4, and begin transmitting frames. Figure 4The example illustrates a scenario where the remaining backoff time of STA5 accidentally conflicts with the random backoff count value of STA4. In this case, a collision may occur between STA4 and STA5. When a collision occurs, neither STA4 nor STA5 receives an ACK, so data transmission fails. In this situation, STA4 and STA5 can double the CW value, select a random backoff count value, and begin a countdown. While the medium is occupied due to the transmissions of STA4 and STA5, STA1 waits; when the medium becomes idle, STA1 waits for DIFS, and then begins frame transmission after the remaining backoff time has elapsed.

[0078] As in Figure 4 In the example, data frames are frames used to send data forwarded to higher layers and can be sent after a backoff performed after DIFS (Distributed Access Frame) from the time the medium becomes idle. Additionally, management frames are frames used to exchange management information that has not been forwarded to higher layers and are sent after a backoff performed after an IFS (Information Support Function) such as DIFS or Point Coordination Function IFS (PIFS). Subtypes of management frames include beacons, association requests / responses, reassociation requests / responses, probe requests / responses, authentication requests / responses, etc. Control frames are frames used to control access to the medium. Subtypes of control frames include request-to-transmit (RTS), clear-to-transmit (CTS), acknowledgment (ACK), power-saving polling (PS-Poll), block ACK (BlockAck), block ACK request (BlockACKReq), empty data packet advertisement (NDP advertisement), and triggers, etc. If the control frame is not a response frame to the previous frame, it is sent after backoff following the DIFS; if it is a response frame to the previous frame, it is sent without backoff following the Short IFS (SIFS). The type and subtype of a frame can be identified by the type field and subtype field in the Frame Control (FC) field.

[0079] The Quality of Service (QoS) STAR can perform a backoff following the Arbitration IFS (AIFS) for the Access Class (AC) to which the frame belongs (i.e., AIFS where i is a value determined by the AC) before the frame can be transmitted. Here, the frame that can use AIFS can be a data frame, management frame, or control frame, rather than a response frame.

[0080] Figure 5 This is a diagram illustrating the CSMA / CA-based frame transmission operation that can be applied to this disclosure.

[0081] As mentioned above, in addition to physical carrier sensing of the medium directly sensed by the STA, the CSMA / CA mechanism also includes virtual carrier sensing. Virtual carrier sensing aims to compensate for problems such as hidden node issues that may occur during medium access. For virtual carrier sensing, the STA's MAC can use the Network Allocation Vector (NAV). The NAV is a value that indicates to other STAs the remaining time until the medium is available for current use or for STAs authorized to use the medium. Therefore, a value set to NAV corresponds to the period during which the STA sending the frame plans to use the medium, and during the corresponding period, STAs receiving the NAV value are prohibited from accessing the medium. For example, the NAV can be configured based on the value of the "Duration" field in the frame's MAC header.

[0082] exist Figure 5 In the example, it is assumed that STA1 intends to send data to STA2, and STA3 is in a position that can eavesdrop on some or all of the frames sent and received between STA1 and STA2.

[0083] To reduce the likelihood of transmission conflicts among multiple STAs in CSMA / CA-based frame transmission operations, a mechanism using RTS / CTS frames can be applied. Figure 5 In the example, when STA1 is transmitting, as a result of carrier sensing by STA3, it can be determined that the medium is in an idle state. That is, STA1 can correspond to a hidden node with respect to STA3. Alternatively, in Figure 5 In the example, it can be determined that while STA2 is transmitting, the carrier sensing result medium of STA3 is in an idle state. That is, STA2 can correspond to a hidden node with respect to STA3. By exchanging RTS / CTS frames before performing data transmission and reception between STA1 and STA2, STAs outside the transmission range of either STA1 or STA2, or STAs outside the carrier sensing range of transmissions from STA1 or STA3, can avoid attempting to occupy the channel during data transmission and reception between STA1 and STA2.

[0084] Specifically, STA1 can determine whether a channel is in use through carrier sensing. Regarding physical carrier sensing, STA1 can determine the channel occupancy / idle status based on the energy level or signal correlation detected in the channel. Alternatively, regarding virtual carrier sensing, STA1 can use a Network Allocation Vector (NAV) timer to determine the channel occupancy status.

[0085] When the channel is idle during DIFS, STA1 can send an RTS frame to STA2 after performing backoff. When STA2 receives the RTS frame, STA2 can send a CTS frame to STA1 after SIFS as a response to the RTS frame.

[0086] If STA3 cannot eavesdrop on CTS frames from STA2 but can eavesdrop on RTS frames from STA1, STA3 can use the duration information included in the RTS frame to set the NAV timer for the subsequent consecutive frame transmission period (e.g., SIFS+CTS frame+SIFS+data frame+SIFS+ACK frame). Alternatively, if STA3 can eavesdrop on CTS frames from STA2, STA3 can also use the duration information included in the CTS frame to set the NAV timer for the subsequent consecutive frame transmission period (e.g., SIFS+data frame+SIFS+ACK frame), even though STA3 cannot eavesdrop on RTS frames from STA1. In other words, if STA3 can eavesdrop on one or more RTS or CTS frames from either STA1 or STA2, STA3 can set the NAV accordingly. When STA3 receives a new frame before the NAV timer expires, STA3 can update the NAV timer using the duration information included in the new frame. STA3 does not attempt channel access until the NAV timer expires.

[0087] When STA1 receives a CTS frame from STA2, STA1 can send a data frame to STA2 after the completion time of CTS frame reception, following SIFS. When STA2 successfully receives the data frame, STA2 can send an ACK frame to STA1 after SIFS as a response to the data frame. When the NAV timer expires, STA3 can determine whether the channel is in use through carrier sensing. If STA3 determines that the channel is not in use by other terminals during the DIFS period after the NAV timer expires, STA3 can attempt channel access after the contention window (CW) for random backoff has expired.

[0088] Figure 6 This is a diagram illustrating an example of a frame structure that can be used in a WLAN system to which this disclosure may be applied.

[0089] Using instructions or primitives (meaning a set of instructions or parameters) from the MAC layer, the PHY layer can prepare the MAC PDU (MPDU) to be transmitted. For example, when the PHY layer receives a command from the MAC layer requesting the start of transmission, it switches to transmit mode, configures the information (e.g., data) provided by the MAC layer in the form of a frame, and transmits it. Additionally, when the PHY layer detects a valid preamble in a received frame, it monitors the preamble header and sends a command to the MAC layer notifying the PHY layer of the start of reception.

[0090] 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.

[0091] A basic PPDU can include a Short Training Field (STF), a Long Training Field (LTF), a Signal (SIG) field, and a Data field. The most basic PPDU format (e.g., Figure 7 The non-HT (high throughput) fields shown can consist solely of a conventional-STF (L-STF), conventional-LTF (L-LTF), conventional-SIG (L-SIG) field, and a data field. Additionally, depending on the PPDU format type (e.g., HT mixed format PPDU, HT green format PPDU, VHT (very high throughput) PPDU, etc.), additional (or different types of) RL-SIG, U-SIG, non-conventional SIG fields, non-conventional STF, non-conventional LTF (i.e., xx-SIG, xx-STF, xx-LTF (e.g., xx is HT, VHT, HE, EHT, etc.)) can be included between the L-SIG field and the data field.

[0092] STF is a signal used for signal detection, automatic gain control (AGC), diversity selection, precise time synchronization, etc., while LTF is a signal used for channel estimation and frequency error estimation. STF and LTF can be referred to as signals used for synchronization and channel estimation in the OFDM physical layer.

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

[0094] The data field may include a service field, a physical layer service data unit (PSDU), and a PPDU tail bit, and may also include padding bits if necessary. Some bits of the service field can be used for synchronization of the descrambler at the receiver. The PSDU corresponds to the MAC PDU defined in the MAC layer and may include data generated / used in the upper layer. The PPDU tail bit can be used to return the encoder to a 0 state. Padding bits can be used to adjust the length of the data field by predetermined units.

[0095] MAC PDUs are defined according to various MAC frame formats, and a basic MAC frame consists of a MAC header, a frame body, and a Frame Check Sequence (FCS). MAC frames can be composed of MAC PDUs and transmitted / received via PSDUs in the data portion of the PPDU format.

[0096] The MAC header includes a frame control field, a duration / ID field, and an address field. The frame control field can include control information required for frame transmission / reception. The duration / ID field can be set to the time used to transmit the corresponding frame, etc. For details on the sequence control, QoS control, and HT control subfields of the MAC header, refer to the IEEE 802.11 standard document.

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

[0098] Figure 7 This is a diagram illustrating an example of a PPDU as defined in the IEEE 802.11 standard of this disclosure.

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

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

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

[0102] Compared to the basic PPDU format, examples of the HE PPDU format (IEEE 802.11ax) additionally include repeated L-SIG (RL-SIG), HE-SIG-A, HE-SIG-B, HE-STF, HE-LTF, and Packet Extension (PE) fields (such as...). Figure 7 (as shown in (d)). Some fields can be excluded, or their lengths can vary depending on the detailed examples of the HE PPDU format. For example, the HE-SIG-B field is included in the HE PPDU format for multi-user (MU), but not in the HE PPDU format for single-user (SU). Furthermore, the HE-Trigger-Based (TB) PPDU format does not include HE-SIG-B, and the length of the HE-STF field can vary up to 8 μs. The Extended Range (HE ER) SU PPDU format does not include the HE-SIG-B field, and the length of the HE-SIG-A field can vary up to 16 μs. For example, RL-SIG can be configured to be the same as L-SIG. Based on the presence of RL-SIG, the receiving STA can determine whether the received PPDU is an HE PPDU or an EHT PPDU, which will be described later.

[0103] EHT PPDU format can include Figure 7 EHT MU (Multi-user) in (e) and Figure 7 The EHT TB (trigger-based) PPDU in (f). The EHT PPDU format is similar to the HE PPDU format in that it includes RL-SIG following L-SIG, but it can include U (generic)-SIG, EHT-SIG, EHT-STF and EHT-LTF following RL-SIG.

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

[0105] Compared to EHT MU PPDU, Figure 7 In (f), the EHT-SIG is omitted from the EHT TB PPDU. The STA that receives the trigger for UL MU transmission (e.g., trigger frame or trigger response schedule (TRS)) can perform UL transmission based on the EHT TB PPDU format.

[0106] The L-STF, L-LTF, L-SIG, RL-SIG, U-SIG (general signal), and EHT-SIG fields can be encoded and modulated so that even conventional STAs can attempt demodulation and decoding, and can be mapped based on a determined subcarrier frequency interval (e.g., 312.5 kHz). These can be referred to as pre-EHT modulated fields. Next, the EHT-STF, EHT-LTF, data, and PE fields can be encoded and modulated to be demodulated and decoded by an STA that has successfully decoded a non-conventional SIG (e.g., U-SIG and / or EHT-SIG) and obtained the information contained in that field, and can be mapped based on a determined subcarrier frequency interval (e.g., 78.125 kHz). These can be referred to as EHT modulated fields.

[0107] 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.

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

[0109] U-SIGs can be constructed in 20MHz units. For example, if an 80MHz PPDU is constructed, U-SIGs can be replicated. That is, the same four U-SIGs can be included in an 80MHz PPDU. PPDUs with bandwidths exceeding 80MHz can include different U-SIGs.

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

[0111] Bit information sent via U-SIG can be divided into version-independent bits and version-dependent bits. For example, U-SIG can be included in... Figure 7 The new PPDU format (e.g., UHR PPDU format) not shown in the figure, 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-related bits can be different.

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

[0113] For example, the version-independent bits of the U-SIG may include a 3-bit Physical Layer Version Identifier (PHY Version Identifier), which can indicate the PHY version (e.g., EHT, UHR, etc.) of the transmitted / received PPDU. The version-independent bits of 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 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.

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

[0115] Information required for PPDU transmission and reception can be included in the U-SIG. For example, the U-SIG may also include information about bandwidth, information about the MCS technique applied to non-traditional SIGs (e.g., EHT-SIG or UHR-SIG), information indicating whether DCM (dual-carrier modulation) techniques (e.g., techniques used to achieve effects similar to frequency diversity by reusing the same signal on two subcarriers) are applied to non-traditional SIGs, information about the number of symbols used for non-traditional SIGs, and information about whether non-traditional SIGs are generated across the entire frequency band.

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

[0117] Preamble puncturing can represent the transmission of a PPDU where no signal is present in one or more frequency units within the bandwidth of the PPDU. For example, the size of the frequency unit (or the resolution of the preamble puncturing) can be defined as 20MHz, 40MHz, etc. For example, preamble puncturing can be applied to PPDU bandwidths of a predetermined size or larger.

[0118] exist Figure 7In the examples, non-traditional SIGs such as HE-SIG-B and EHT-SIG can include control information for receiving STAs. Non-traditional SIGs can be transmitted on at least one symbol, and a symbol can have a length of 4 μs. Information regarding the number of symbols used for EHT-SIGs can be included in previous SIGs (e.g., HE-SIG-A, U-SIG, etc.).

[0119] Non-traditional SIGs such as HE-SIG-B and EHT-SIG can include both public and user-specific fields. These public and user-specific fields can be encoded separately.

[0120] In some cases, the common field can be omitted. For example, in compressed mode using non-OFDMA (Orthogonal Frequency Division Multiple Access), the common field can be omitted, and multiple STAs can receive PPDUs (e.g., the data field of the PPDU) through the same frequency band. In uncompressed mode using OFDMA, multiple users can receive PPDUs (e.g., the data field of the PPDU) through different frequency bands.

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

[0122] The common fields may include CRC bits and a tail bit, where the CRC bits can be 4 bits long and the tail bit can be 6 bits long and set to 000000. The common fields may also include RU allocation information. RU allocation information may include information about the locations of RUs to which multiple users (i.e., multiple receiving STAs) are assigned.

[0123] An RU can include multiple subcarriers (or tones). RUs can be used when transmitting signals to multiple STAs based on OFDMA technology. Additionally, RUs can be defined even when transmitting signals to a single STA. Resources can be allocated to non-traditional STFs, non-traditional LTFs, and data fields on a RU basis.

[0124] The appropriate RU size can be defined based on the PPDU bandwidth. RUs can be defined the same or different for the applied PPDU format (e.g., HEPPDU, EHT PPDU, UHR PPDU, etc.). For example, in the case of an 80MHz PPDU, the RU layout for HEPPDU and EHT PPDU can be different. The applicable RU size, number and location of RUs, DC (direct current) subcarrier locations and numbers, empty subcarrier locations and numbers, guard subcarrier locations and numbers, etc., for each PPDU bandwidth can be referred to as the tone scheme. For example, a tone scheme for high bandwidth can be defined as multiple iterations of a low-bandwidth tone scheme.

[0125] RUs of various sizes can be defined as 26-tone RUs, 52-tone RUs, 106-tone RUs, 242-tone RUs, 484-tone RUs, 996-tone RUs, 2×996-tone RUs, 3×996-tone RUs, etc. MRUs (Multiple RUs) differ from multiple individual RUs and correspond to a group of subcarriers composed of multiple RUs. For example, an MRU can be defined as 52+26 tones, 106+26 tones, 484+242 tones, 996+484 tones, 996+484+242 tones, 2×996+484 tones, 3×996 tones, or 3×996+484 tones. Furthermore, the multiple RUs constituting an MRU can be consecutive or non-consecutive in the frequency domain.

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

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

[0128] Figure 8 This is a diagram illustrating an example format of the trigger frame that can be applied to this disclosure.

[0129] A trigger frame can allocate resources for the transmission of one or more TB PPDUs and request the transmission of TB PPDUs. The trigger frame may also include additional information required by the STA sending the TB PPDU in response. The trigger frame may include public information and user information list fields in the frame body.

[0130] The common info field is information typically used for the transmission of one or more TB PPDUs requested by a trigger frame, such as trigger type, UL length, presence or absence of subsequent trigger frames (e.g., more TFs), CS (channel sensing) request, UL BW (bandwidth), HE / EHT P160, special user information field flags, etc.

[0131] The 4-bit trigger type subfield can have values ​​from 0 to 15. Values ​​0, 1, 2, 3, 4, 5, 6, and 7 are defined to correspond to Basic, Beamforming Report Polling (BFRP), Multi-User Block Acknowledgment Request (MU-BAR), Multi-User Request Transmission (MU-RTS), Buffer Status Report Polling (BSRP), Multicast with Retry (GCR), MU-BAR, Bandwidth Query Report Polling (BQRP), and NDP Feedback Report Polling (NFRP), respectively. Values ​​8 through 15 are reserved.

[0132] In public information, the trigger-related public information subfields may include information that can be optionally included based on the trigger type.

[0133] Special user information fields can be included in the trigger frame. These fields do not include user-specific information, but rather extended public information not provided in the public information fields.

[0134] The user information list includes zero or more user information fields. Figure 8 An example of the EHT variant user information field format is shown.

[0135] The AID12 subfield essentially indicates that it is a user information field for a STA with the corresponding AID. Furthermore, if the AID12 field has a specific predetermined value, it can be used for other purposes, such as assigning a Random Access (RA)-RU or being configured as a special user information field. A special user information field is a user information field that does not include user-specific information but includes extended public information not provided in the public information field. For example, a special user information field can be identified by the AID12 value 2007, and the special user information field flag subfield within the public information field can indicate whether a special user information field is included.

[0136] The RU allocation subfield can indicate the size and location of the RU / MRU. For this purpose, the RU allocation subfield can be interpreted together with the PS160 (primary / secondary 160MHz) subfield of the user information field and the UL BW subfield of the public information field.

[0137] Multiple Access Point (MAP) Operation

[0138] The following describes an example of this disclosure for multi-access point (MAP) operation.

[0139] MAP operation can be a general term for a technique in which multiple APs / STAs cooperate with each other to send and receive data when performing communication with other STAs. MAP operation can include a first method (i.e., a multi-AP / STA cooperative transmission method) and a second method (i.e., a multi-AP / STA coordination method). In the first method, multiple APs simultaneously send data to a STA. In the second method, appropriate APs among the multiple APs divide an appropriate area (e.g., a frequency / time / spatial area) and then send data to a specific STA (i.e., the appropriate STA).

[0140] Specifically, the first method may include a method in which multiple APs / STAs perform a common transmission method (e.g., a coordinated space reuse (C-SR) method) to each STA and a method in which multiple APs / STAs perform joint transmission (e.g., a joint transmission (J-TX) method) to the same STA.

[0141] In the C-SR scheme, multiple APs / STAs can share channel information with the STA (e.g., transmit power (Tx power), RSSI (Received Signal Strength Indicator), etc.) and can simultaneously perform communication with the STA based on the channel information. In the J-TX scheme, multiple APs / STAs can share channels and data with the STA and can simultaneously perform communication with the STA based on the shared channels and data.

[0142] As mentioned above, the second method refers to the method of dividing the AP / STA into frequency domain, time domain, or spatial domain and communicating with other STAs in the divided domain. Frequency domain-based communication methods may include the C (concurrent)-OFDMA method, time domain-based communication methods may include AP selection, relay operation, and V (virtual)-BSS method, and spatial domain-based communication methods may include the C (coordination)-BF (beamforming) method, etc.

[0143] For example, in frequency-domain-based communication methods, multiple APs / STAs can share channel information with STAs based on frequency bands, and select appropriate frequency bands based on the shared channel information. Multiple APs / STAs can then perform communication with STAs within the selected frequency bands.

[0144] As another example, in the case of a time-domain-based communication method, a representative AP can be configured to guide communication by having the STA select the appropriate AP / STA (here, also including the representative AP).

[0145] As another example, in the case of spatially based communication methods, multiple APs / STAs can share channel information with STAs and calculate a BF matrix suitable for communication by each AP or without interfering with other APs. Multiple APs / STAs can then perform communication with STAs based on the calculated BF matrix.

[0146] To support the MAP operation described above, the representative AP can select and designate the AP / STA (hereinafter referred to as the participating AP / STA) to communicate with the STA.

[0147] The representative AP (here, the representative AP can be replaced by the primary AP, sharing AP, or main AP) initiates and controls MAP operations for transmission and reception among multiple APs. The representative AP groups participating APs and manages links with them, enabling information sharing among the participating APs. The representative AP manages information about the BSS comprised of the participating APs and about the STAs associated with the BSS.

[0148] Participating APs (which can be replaced by slave APs, shared APs, auxiliary APs, etc.) are associated with the representative AP and can share control information, management information, and data services with each other. Participating APs perform the same basic functions as APs that can establish a BSS in a wireless LAN.

[0149] In MAP operations, participating STAs can be associated with participating APs or representative APs and form BSSs.

[0150] In a MAP environment, the representative AP and participating APs can directly send and receive data from each other. The representative AP and STA can choose not to directly send and receive data from each other. A participating AP (e.g., a participating AP already bound to an STA) can directly send and receive data with the STA. One of the participating APs can become the representative AP.

[0151] Here, the DL or UL process for MAP operation can consist of the following steps: 1) the step of guiding / selecting participating APs by the representative AP, 2) the step of sending DL data or DL ​​trigger frames to the STAs of the participating APs, 3) the step of sending ACK or UL data from the receiving STAs to the participating APs, and 4) the step of reporting the results to the representative AP of the participating APs.

[0152] Here, the steps between step 1) and step 2) may include: the participating AP sends an ACK indicating the representative AP, and the representative AP sends a (re)scheduling indication message to the participating AP that sent the ACK. Additionally, the steps between step 3) and step 4) may include: when performing the UL procedure, the participating AP sends an ACK to the STA.

[0153] Previously, there was no defined process or related protocol for triggering the DL / UL procedure for the aforementioned MAP operation to achieve efficient resource utilization. The following section will specifically describe step 1 of the DL / UL procedure for the aforementioned MAP operation (i.e., the steps for a representative AP to trigger a MAP operation).

[0154] Figure 9 This is a diagram used to explain the operations performed by the first AP according to one embodiment of this disclosure. Figure 9 and Figure 10 In this context, the first AP can be a participating AP in a multi-AP operation, and the second AP can be a representative AP that triggers the multi-AP operation.

[0155] The first AP can receive a Multi-User (MU) Request to Send (RTS) Transmission Opportunity Sharing (TXS) trigger frame (S910) from the second AP.

[0156] Here, the MU-RTS TXS trigger frame may include first information instructing the MU-RTS TXS trigger frame to allocate / share for transmission opportunities (TXOPs) associated with multi-AP operation and second information associated with the first AP.

[0157] For example, the first information can be indicated by the triggered TXOP shared mode subfield included in the common information field of the MU-RTS TXS trigger frame. Here, the value of the triggered TXOP shared mode subfield can be set to 3. However, this is only one implementation, and the value of the triggered TXOP shared mode subfield can also be set to 1 or 2.

[0158] Furthermore, the second information may include at least one of the first AP's BSSID (Basic Service Set Identifier) ​​or BSS color.

[0159] Additionally, the MU-RTS TXS trigger frame may include third information indicating the multi-AP operation type and fourth information related to the multi-AP operation type. For example, the third information may indicate at least one of Coordinated (C)-TDMA (Time Division Multiple Access), Coordinated (C)-OFDMA (Orthogonal Frequency Division Multiplexing), Coordinated (C)-SR (Spatial Reuse), Joint Transmission (J-TX), or Coordinated (C)-BF (Beamforming).

[0160] The fourth information can be set differently depending on the multi-AP operation type indicated by the third information. For example, if the third information indicates C-SR, the fourth information may include the ID of the first AP and recommended TX power information, etc. If the third information indicates J-TX, the fourth information may include common BSS color information to be used in the U-SIG field, etc.

[0161] Furthermore, the MU-RTS TXS trigger frame may include one or more user information fields. The specific user information field corresponding to the first AP among the one or more user information fields may include information instructing the first AP to send at least one of the frequency resources or time periods of the first AP to transmit the DL PPDU or the first trigger frame.

[0162] As an example of this disclosure, a time period for the first AP to send a DL PPDU or a first trigger frame (or / and a TXOP allocated by the MU-RTS TXS trigger frame) can be allocated within the target wake-up time (TWT) period set by the second AP.

[0163] Based on the MU-RTS TXS trigger frame, the first AP can send a downlink (DL) physical layer protocol data unit (PPDU) or a first trigger frame (S920) to at least one STA. Here, at least one STA can refer to a STA associated with the first AP (i.e., connected to the first AP) (e.g., a non-AP STA).

[0164] For example, the first AP can send a DL PPDU to at least one STA associated with the first AP based on a MU-RTS TXS trigger frame.

[0165] As another example, a first AP may send a first trigger frame to at least one STA. The first trigger frame may request uplink (UL) TB (trigger-based) PPDU transmission from at least one STA associated with the first AP. That is, at least one STA may send a UL TB PPDU to the first AP based on the first trigger frame.

[0166] As another example of this disclosure, the first AP may send a response frame (e.g., an ACK frame) to the second AP in response to the MU-RTS TXS trigger frame. The first AP may receive a second trigger frame from the second AP to participate in multi-AP operation and / or rescheduling.

[0167] Here, the second trigger frame (or MAD, described later) may include fifth information indicating whether the first AP sends a DL PPDU or the first trigger frame. Accordingly, the first AP may send a DL PPDU or the first trigger frame to at least one STA based on the MU-RTS TXS trigger frame and / or the second trigger frame. Additionally, the second trigger frame may include a trigger type subfield indicating the association of the second trigger frame with multi-AP operation, and the value of the trigger type subfield may be set to one of 9 to 15.

[0168] The first AP can receive an ACK frame for a DL PPDU or UL TB PPDU from at least one STA based on a first trigger frame. The first AP can report to the second AP the results of data transmission and reception between at least one STA (e.g., information related to the UL TB PPDU and / or ACK frame received from at least one STA).

[0169] Figure 9 The method described in the example, executed by the first AP, can be performed by... Figure 1 The first device (100) is executed. For example, Figure 1 One or more processors (102) of the first device (100) may receive MU-RTS TXS trigger frames from the second AP via one or more transceivers (106). One or more processors (102) may send DL PPDU or first trigger frames to at least one STA via one or more transceivers (106) based on the MU-RTS TXS trigger frames.

[0170] The aforementioned memory (104) can store data that is executed by one or more processors (102). Figure 9 The instructions for the methods described in the example.

[0171] Figure 10 This is a diagram used to explain the operation performed by the second AP according to one embodiment of the present disclosure.

[0172] The second AP can send a MU-RTS TXS trigger frame (S1010) to the first AP.

[0173] As an example of this disclosure, the second AP may send a MU-RTS TXS trigger frame to at least one AP including the first AP. As an example, at least one of various methods (e.g., C-TDMA method, C-OFDMA method, C-SR method, J-TX method, etc.) may be indicated by the MU-RTS TXS trigger frame, and at least one AP may perform various communication operations in the indicated method.

[0174] As another example, the second AP can send MU-RTS TXS trigger frames to at least one AP including the first AP in various ways (e.g., C-TDMA, C-OFDMA, C-SR, J-TX, etc.).

[0175] The second AP can receive information from the first AP about the results of data transmission and reception between at least one STA (S1020).

[0176] Specifically, the second AP can receive information from the first AP about the results of data transmission and reception performed between at least one STA.

[0177] For example, based on the MU-RTS TXS trigger frame, a DL PPDU or a first trigger frame can be sent from a first AP to at least one STA. Furthermore, the first AP can receive an ACK frame for the DL PPDU or UL TB PPDU from at least one STA based on the first trigger frame. The first AP can also send information related to the ACK frame for the DL PPDU or UL TB PPDU as result information to a second AP based on the first trigger frame.

[0178] Figure 10 The method described in the example, executed by the second AP, can be performed by... Figure 1 The second device (200) performs the operation. For example, Figure 10 One or more processors (202) of the second device (200) can send MU RTS TXS trigger frames to the first AP via one or more transceivers (206). One or more processors (202) can receive data transmission / reception result information between at least one STA and the first AP via one or more transceivers (206).

[0179] Furthermore, one or more memories (204) of the second device (200) may store data that is executed by one or more processors (202). Figure 10 The instructions for the methods described in the example.

[0180] The method for indicating / triggering a representative AP will be described in detail below. The representative AP can indicate / trigger a MAP by applying at least one of the embodiments 1 to 3 described below.

[0181] In describing this disclosure, the MAP DL trigger frame is represented as MAD. MAD can be based on... Figure 8 The structure configuration of the trigger frame shown can also be a trigger frame defined for a new trigger type used to trigger MAP operations. As another example, MAD can be defined as a new control frame for MAP operations.

[0182] Figure 8 The trigger frame shown is sent to trigger a UL TB PPDU, but in this disclosure, a MAD can be sent to trigger a DL PPDU participating in an AP.

[0183] Embodiment 1

[0184] Implementation 1 relates to a method (or, a short-term method) in which a representative AP directly instructs participating APs to send a MAP (e.g., a transmission). The representative AP can trigger a DL PPDU transmission by sending a MAD to the participating APs.

[0185] As an example of this disclosure, the MAD may include at least one of the following: information indicating trigger frame indicating multi-AP operation, DL / UL indication information, TA / RA information, multi-AP type information, address information of participating APs, ID information of participating APs, length or transmission opportunity (TXOP) information, frequency band information, GI and LTF information, and Tx power information.

[0186] Specifically, the trigger frame can be used to indicate whether it triggers a MAP (e.g., triggering a DL PPDU transmission to a STA participating in the AP or triggering a trigger frame transmission to the AP) by including a trigger type field in the common information field of the trigger frame. Here, the value of the trigger type field can be set to one of 9 to 15. Alternatively, the MAD can be defined as a new control frame used to trigger the MAP.

[0187] The DL / UL indication information can indicate whether the MAD indicates a DL transmission by a participating AP or a trigger frame transmission by the participating AP. For example, if the DL / UL indication information indicates a DL transmission by a participating AP, the participating AP can send a DL PPDU to the STA based on the MAD. As another example, if the DL / UL indication information indicates a trigger frame transmission by a participating AP, the participating AP can send a trigger frame to the STA based on the MAD, and the STA can send a UL PPDU to the participating AP / representative AP based on the received trigger frame.

[0188] The TA field of the MAD can be set to the address of the STA (i.e., the representative AP) that sent the MAD. If there is a participating AP, the RA field of the MAD can be set to the address of the participating AP. If there is more than one participating AP, the RA field of the MAD can be set to the broadcast address. Alternatively or additionally, the MAD may include the addresses of the participating APs (e.g., BSSID, BSS color, or MAP group ID, etc.). That is, the MAD may include the ID information of the participating APs (such as BSS color or BSSID) instead of the existing STA ID (e.g., AID).

[0189] MAP type information can indicate at least one of MAP-related methods such as J-TX, C-OFDMA, C-SR, and C-BF.

[0190] The length information included in the MAD may include the value of the L-SIG length field of the requested DL PPDU transmitted from the participating AP. The TXOP information included in the MAD may include information related to the TXOP for the DL PPDU transmitted by the participating AP. The frequency band information included in the MAD may include the entire frequency band and / or frequency zone (BW or RU allocation information) of the PPDU of each participating AP.

[0191] The GI and LTF information included in the MAD can include the GI, LTF type, and symbol count information of the PPDUs sent from each participating AP. The GI and LTF information can be set collectively for each participating AP, but is not limited to this. The GI and LTF information can be set for each participating AP individually.

[0192] The Tx power information included in the MAD may include the TX power information of a representative AP or the Tx power information of each participating AP.

[0193] Embodiment 2

[0194] Implementation 2 relates to a method for a representative AP to indicate the MAP period (i.e., the transmission duration and / or mid-term) to participating APs. As an example, the representative AP may indicate the MAP period to participating APs via a MU-RTS (Request to Send) TXS (Transmission Opportunity Sharing) frame.

[0195] In a basic wireless LAN system, the MU-RTS TXS trigger frame may include a triggered TXOP sharing mode subfield. When the value of the triggered TXOP sharing mode subfield is set to 1 or 2, it can indicate the duration of the TXOP between the scheduled STA and its associated AP or another STA.

[0196] In one embodiment of this disclosure, the value of the triggered TXOP sharing mode subfield can be set to 1 or 2 to indicate TXOP-related information for a MAP operation. As another example, the triggered TXOP sharing mode subfield can be newly defined (i.e., a triggered TXOP sharing mode subfield with a value of 3) to indicate information related to TXOPs for a MAP operation (e.g., TXOP interval, TXOP allocation method, etc.).

[0197] A MU-RTS TXS trigger frame may include one or more user information fields. These user information fields may include at least one of the following: information about the participating AP (e.g., the BSSID or BSS color of the participating AP instead of an existing AID), an RU allocation subfield, a PS160 subfield, an allocation duration subfield, information related to the MAP operation type, or a group ID for the MAP operation.

[0198] Here, the RU allocation subfield and PS160 subfield can include (frequency) allocation information for each participating AP, rather than information about which band among the main 20 / 40 / 80 / 160 bands should be used to transmit CTS. Information related to the MAP operation type can include the MAP operation type (e.g., C-TDMA, C-OFDMA, C-SR, J-TX, etc.) and information related to the corresponding MAP operation type (e.g., recommended TX power information, common BSS color information to be used in the U-SIG field in J-TX, etc.).

[0199] After sending the MU-RTS TXS trigger frame indicating MAP operation, the participating AP can send a response CTS frame after SIFS. In this case, the response CTS frame can be sent through the RU allocation area indicated by the MU-RTS TXS trigger frame instead of through the main 20 / 40 / 80 / 160 units. The operation of the participating AP can begin immediately after sending the response CTS frame.

[0200] Here, the area allocated to participating APs that did not send a response CTS frame may be wasted. Therefore, a rescheduling or approval trigger frame for the representative AP can be sent to the participating AP. Here, the trigger frame can be MAD or as defined in Implementation 1. Figure 8 The trigger frame.

[0201] Embodiment 2-1

[0202] Implementation 2-1 relates to the case of MAP operation type indication C-TDMA. The representative AP can sequentially allocate a portion of the TXOP duration to each participating AP.

[0203] For example, a MU-RTS TXS trigger frame can allocate a portion of a TXOP to a participating AP. Here, the additional (more) TF (trigger frame) subfield of the common information field of the MU-RTS TXS trigger frame can indicate that the transmission of a subsequent trigger frame is scheduled. A portion of a TXOP can be allocated to another participating AP via the next MU-RTS TXS trigger frame indicated by the more TF subfield.

[0204] Embodiment 2-2

[0205] Implementation 2-2 relates to the case of MAP operation type indication C-OFDMA. Representative APs can collectively allocate a portion of the TXOP duration to all participating APs.

[0206] For example, a MU-RTS TXS trigger frame may include multiple user information fields, and each user information field may include the ID information and frequency domain information of the participating AP. Here, the allocation duration value included in each user information field can be the same.

[0207] Embodiment 2-3

[0208] Implementation methods 2-3 involve the case of MAP operation type indication C-SR (space reuse). Representative APs can collectively allocate a portion of the TXOP duration to all participating APs.

[0209] For example, a MU-RTS TXS trigger frame may include multiple user information fields, and each user information field may include the ID information of the participating AP and the recommended TX power information and / or MCS (modulation and coding scheme). Here, the frequency domain information and the allocation interval value included in each user information field may be the same.

[0210] Embodiment 3

[0211] Implementation 3 relates to a method by which a representative AP indicates to participating APs the duration (e.g., long duration) of a MAP operation. As an example, the representative AP may assign a TWT (Target Wake-Up Time) interval to the participating APs.

[0212] Here, TWT stands for Power Saving Technology (PS). This PS technology can improve the energy efficiency of non-AP STAs by defining the service period (SP) between AP STAs and non-AP STAs and sharing information about the SP, thereby reducing media contention.

[0213] The STA that executes requests / suggestions / requirements during the TWT establishment phase can be called a TWT request STA. Additionally, the AP that responds to the request (such as accept / reject) can be called a TWT response STA.

[0214] The setup phase may include the process of determining / defining the TWT request from the STA to the AP, the type of TWT operation to be performed, and the types of frames to be sent and received. TWT operations can be divided into individual TWTs and broadcast TWTs.

[0215] A standalone TWT is a mechanism used to perform data exchange after the AP and non-AP STAs have negotiated the wake-up / sleep state of the non-AP STA through the sending and receiving of TWT request / response frames.

[0216] A broadcast TWT is a TWT in which a non-AP STA (or a TWT-scheduled STA) obtains information about the Target Beacon Transmission Time (TBTT) and listening interval by sending and receiving TWT request / response frames with the AP (or the TWT-scheduled STA). Negotiation of the TBTT can be performed here. Based on this, the AP can define frames that include scheduling information for the TWT via beacon frames.

[0217] In one embodiment of this disclosure, a representative AP may indicate that it is a portion of the MAP operation (i.e., the TWT interval) and may not indicate the active / sleep state separately.

[0218] Therefore, STAs without MAP-related capabilities can enter a sleep state, and a silence interval can be set for the corresponding STA. Here, MAP-related capabilities can be set / defined for each MAP technology and the entire MAP operation. Here, STAs entering TWT and sleep states can be set for each MAP technology. When the TWT interval begins, the representative AP can send the MAD trigger frame defined in Implementation 1 to the participating APs.

[0219] Each of the methods described in Embodiment 1, Embodiment 2 and Embodiment 3 can be used / applied in combination with each other.

[0220] As an example of this disclosure, if the representative AP supports STR (Simultaneous Transmission and Receive), it may not be necessary to match DL or UL transmission synchronization when allocating FDM resources among participating APs. Therefore, trigger frames for simultaneous transmissions may not be required. Additionally, the representative AP may send frames defining transmission intervals (e.g., frames defining TWT intervals, etc.) and / or MU-RTS TXS trigger frames to participating APs.

[0221] As another example of this disclosure, when the representative AP is an NSTR (non-simultaneous transmit and receive), DL or UL transmission synchronization may be required when allocating FDM resources among participating APs. Therefore, a trigger frame for simultaneous DL transmission may be needed, and after sending the trigger frame and SIFS, simultaneous FDM transmissions (e.g., DL MU A-PPDU transmissions, etc.) can be performed among the participating APs. Transmission intervals for MAP operations can be defined in advance (e.g., TWT intervals and / or intervals determined by MU-RTS TXS trigger frames).

[0222] The above embodiments combine the elements and features of this disclosure in a predetermined form. Unless otherwise expressly stated, each element or feature should be considered optional. Each element or feature may be implemented without being combined with other elements or features. Furthermore, embodiments of this disclosure may include combinations of some elements and / or features. The order of operations described in embodiments of this disclosure may be changed. Some elements or features of one embodiment may be included in other embodiments, or may be replaced by corresponding elements or features of other embodiments. Obviously, embodiments may include claims that are not explicitly referenced in the claims, or may be included as new claims after the application has been amended.

[0223] It will be apparent to those skilled in the art that this disclosure may be implemented in other specific forms without departing from its essential characteristics. Therefore, the foregoing detailed description should not be construed as restrictive in every respect, but rather as illustrative. The scope of this disclosure should be determined by a reasonable interpretation of the appended claims, and all variations within the equivalent scope of this disclosure are included within its scope.

[0224] The scope of this disclosure includes software or machine-executable commands (e.g., operating systems, applications, firmware, programs, etc.) that operate in a device or computer according to methods of various embodiments, and non-transitory computer-readable media that cause software or commands to be stored and executable in a device or computer. Commands that can be used to program a processing system to perform the features described in this disclosure can be stored in a storage medium or a computer-readable storage medium, and the features described in this disclosure can be implemented by using a computer program product including such a storage medium. The storage medium may include, but is not limited to, high-speed random access memory, such as DRAM, SRAM, DDR RAM, or other random access solid-state storage devices, and may include non-volatile memory, such as one or more disk storage devices, optical disk storage devices, flash memory devices, or other non-volatile solid-state storage devices. The memory may optionally include one or more storage devices located remotely from the processor. The memory, or alternatively, the non-volatile memory devices in the memory include non-transitory computer-readable storage media. The features described in this disclosure can be stored in any machine-readable medium to control the hardware of a processing system and can be integrated into software and / or firmware that allows the processing system to interact with other mechanisms using results from embodiments of this disclosure. Such software or firmware may include, but is not limited to, application code, device drivers, operating systems, and execution environments / containers.

[0225] Industrial applicability

[0226] The methods proposed in this disclosure have been described with emphasis on examples applied to IEEE 802.11-based systems, but in addition to IEEE 802.11-based systems, the methods proposed in this disclosure can also be applied to various WLAN or wireless communication systems.

Claims

1. A method performed by a first access point (AP) in a wireless LAN system, the method comprising the following steps: Receive a multi-user MU request from the second AP and send an RTS transmission opportunity-sharing TXS trigger frame; Based on the MU-RTS TXS trigger frame, a downlink DL physical layer protocol data unit (PPDU) or a first trigger frame is sent to at least one STA. The MU-RTS TXS trigger frame includes first information indicating the allocation of a transmission opportunity (TXOP) related to multi-AP operation and second information related to the first AP.

2. The method according to claim 1, wherein, The first trigger frame requests an uplink UL TB based trigger PPDU transmission for at least one STA associated with the first AP.

3. The method according to claim 1, wherein, The second information includes at least one of the BSSID (Basic Service Set Identifier) ​​or BSS color of the first AP.

4. The method according to claim 1, wherein, The first information is indicated by the triggered TXOP shared mode subfield included in the public information field of the MU-RTS TXS trigger frame, and The value of the triggered TXOP shared mode subfield is set to 3.

5. The method according to claim 1, wherein, The MU-RTS TXS trigger frame includes third information indicating the multi-AP operation type and fourth information related to the multi-AP operation type, and The third information indicates at least one of C-coordinated-TDMA time division multiple access, C-coordinated-OFDMA orthogonal frequency division multiplexing, C-coordinated-SR spatial reuse, J-TX joint transmission, or C-coordinated-BF beamforming.

6. The method according to claim 1, wherein, The MU-RTS TXS trigger frame includes at least one user information field, and The specific user information field corresponding to the first AP in the at least one user information field includes information instructing the first AP to send at least one of the frequency resources or time periods of the DL PPDU or the first trigger frame.

7. The method according to claim 1, wherein, The first AP sends a response frame to the second AP in response to the MU-RTS TXS trigger frame, and A second trigger frame is sent from the second AP to the first AP to confirm participation in the multi-AP operation.

8. The method according to claim 7, wherein, The second trigger frame includes fifth information indicating whether the first AP will send the DL PPDU or the first trigger frame.

9. The method according to claim 7, wherein, The second trigger frame includes a trigger type subfield indicating the relationship between the second trigger frame and the multi-AP operation, and The value of the trigger type subfield is set to one of 9 to 15.

10. The method according to claim 6, wherein, The time period during which the first AP sends the DL PPDU or the first trigger frame is allocated within the TWT period set by the second AP.

11. The method according to claim 1, wherein, The first AP is a participating AP in a multi-AP operation, and The second AP is a representative AP that triggers multi-AP operations.

12. A first access point (AP) operating in a wireless LAN system, the first AP comprising: At least one transceiver; as well as At least one processor, said at least one processor being coupled to said at least one transceiver, Wherein, the at least one processor is configured to: The at least one transceiver receives a multi-user MU request from the second AP to send an RTS transmission opportunity sharing TXS trigger frame; Based on the MU-RTS TXS trigger frame, a downlink DL physical layer protocol data unit (PPDU) or a first trigger frame is sent to at least one STA via the at least one transceiver. The MU-RTS TXS trigger frame includes first information indicating the allocation of a transmission opportunity (TXOP) related to multi-AP operation and second information related to the first AP.

13. A method performed by a second access point (AP) in a wireless LAN system, the method comprising the following steps: Send a multi-user MU request to the first AP and send an RTS transmission opportunity sharing TXS trigger frame; as well as Receive data transmission and reception result information between at least one STA from the first AP. Specifically, based on the MU-RTS TXS trigger frame, the first AP sends a downlink DL physical layer protocol data unit (PPDU) or a first trigger frame to the at least one STA, and The MU-RTS TXS trigger frame includes first information indicating the allocation of a transmission opportunity (TXOP) related to multi-AP operation and second information related to the first AP.

14. A second access point (AP) operating in a wireless LAN system, the second AP comprising: At least one transceiver; as well as At least one processor, said at least one processor being coupled to said at least one transceiver, Wherein, the at least one processor is configured to: The at least one transceiver sends a multi-user MU request to the first AP to send an RTS transmission opportunity sharing TXS trigger frame; and The at least one transceiver receives data transmission and reception result information between at least one STA from the first AP. Specifically, based on the MU-RTS TXS trigger frame, the first AP sends a downlink DL physical layer protocol data unit (PPDU) or a first trigger frame to the at least one STA, and The MU-RTS TXS trigger frame includes first information indicating the allocation of a transmission opportunity (TXOP) related to multi-AP operation and second information related to the first AP.

15. A processing device configured to control a first access point (AP) operating in a wireless LAN system, the processing device comprising: At least one processor; as well as At least one computer memory, operatively connected to the at least one processor and storing instructions that perform operations based on execution by the at least one processor, the operations including: Receive a multi-user MU request from the second AP and send an RTS transmission opportunity-sharing TXS trigger frame; Based on the MU-RTS TXS trigger frame, a downlink DL physical layer protocol data unit (PPDU) or a first trigger frame is sent to at least one STA. The MU-RTS TXS trigger frame includes first information indicating the allocation of a transmission opportunity (TXOP) related to multi-AP operation and second information related to the first AP.

16. At least one non-transitory computer-readable medium, said non-transitory computer-readable medium storing at least one instruction, in, The at least one instruction, executable by at least one processor, can control a device in a wireless LAN system: Receive a multi-user MU request from the second AP and send an RTS transmission opportunity-sharing TXS trigger frame; Based on the MU-RTS TXS trigger frame, a downlink DL physical layer protocol data unit (PPDU) or a first trigger frame is sent to at least one STA. The MU-RTS TXS trigger frame includes first information indicating the allocation of a transmission opportunity (TXOP) related to multi-AP operation and second information related to the first AP.

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