Method and apparatus for transmitting or receiving in enhanced triggen transmission opporty sharing procedure in

Abstract

Disclosed are a method and an apparatus for transmitting or receiving in an enhanced trigger transmission opportunity sharing procedure in a wireless LAN system. According to an embodiment disclosed herein, a method performed by a station (STA) in a wireless LAN system comprises the steps of: receiving a trigger frame related to sharing of a transmission opportunity (TXOP) from an access point (AP); and transmitting a response frame to the trigger frame to the AP. The trigger frame includes a common information field and a plurality of user information fields for a plurality of STAs including the STA, and a starting point of a time period allocated to the STA in the TXOP may be identified based on an order of the user information fields for the STA among the plurality of user information fields.

Description

Technical Field

[0001] The present disclosure relates to a method and apparatus for transmitting or receiving in an enhanced triggered transmission opportunity (TXOP) sharing procedure in a wireless local area network (WLAN) system. Background Art

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

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

[0004] Technical issues

[0005] The technical objective of the present disclosure is to provide a method and apparatus for transmitting or receiving in an enhanced triggered transmission opportunity (TXOP) sharing process in a wireless WLAN system.

[0006] Another technical object of the present disclosure is to provide a method and apparatus for supporting multiple peer-to-peer (P2P) communications in a triggered transmission opportunity sharing process in a wireless LAN system.

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

[0008] Technical Solution

[0009] According to one aspect of the present disclosure, a method performed by a station (STA) in a wireless LAN system may include: receiving a trigger frame related to sharing of a transmission opportunity (TXOP) from an access point (AP); and sending a response frame to the trigger frame to the AP. Here, the trigger frame may include a common information field and a plurality of user information fields for a plurality of STAs including the STA, and the timing of a duration allocated to the STA within the TXOP may be identified based on the order of the user information fields for the STA among the plurality of user information fields.

[0010] According to another aspect of the present disclosure, a method performed by an access point (AP) in a wireless LAN system may include: sending a trigger frame related to sharing of a transmission opportunity (TXOP) to a plurality of stations (STAs); and receiving a response frame to the trigger frame from one or more STAs among the plurality of STAs. Here, the trigger frame may include a common information field and a plurality of user information fields for a plurality of STAs including the STA, and the timing of a duration allocated to the STA within the TXOP may be determined based on an order of the user information field for each STA among the plurality of user information fields.

[0011] Technical Effects

[0012] According to the present disclosure, a method and apparatus for transmitting or receiving in an enhanced triggered transmission opportunity sharing process in a wireless LAN system may be provided.

[0013] According to the present disclosure, a method and apparatus for supporting multiple P2P communications in a triggered transmission opportunity sharing process in a wireless LAN system may be provided.

[0014] According to the present disclosure, a method and apparatus for performing P2P communication by a plurality of stations (STAs) as required in a wireless LAN system can be provided.

[0015] Effects achievable by the present disclosure are not limited to the above-described effects, and other effects not described herein may be clearly understood by those skilled in the relevant art through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

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

[0019] Figure 3 It is a diagram for explaining a link establishment process to which the present disclosure can be applied.

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

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

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

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

[0024] Figure 8 is a diagram illustrating an exemplary format of a trigger frame to which the present disclosure can be applied.

[0025] Fig. 9 is a diagram for explaining an example of a triggered TXOP sharing procedure to which the present disclosure may be applied.

[0026] Fig.10 is a diagram for explaining an operation of an STA in a triggered TXOP sharing procedure according to the present disclosure.

[0027] Fig.11 is a diagram for explaining an operation of an AP in a triggered TXOP sharing procedure according to the present disclosure.

[0028] Fig.12 is a diagram for explaining an example of a triggered TXOP sharing procedure according to an example of the present disclosure.

[0029] Fig.13 is a diagram for explaining an example of a TXOP sharing triggering procedure according to another example of the present disclosure.

[0030] Fig.14 is a diagram for explaining an example of a TXOP sharing triggering procedure according to another example of the present disclosure.

[0031] Fig.15 is a diagram for explaining a TXOP sharing triggering process according to another example of the present disclosure.

[0032] Fig.16 is a diagram for explaining a TXOP sharing triggering process according to another example of the present disclosure. DETAILED DESCRIPTION

[0033] Hereinafter, embodiments according to the present disclosure will be described in detail with reference to the accompanying drawings. The detailed description disclosed by the accompanying drawings is intended to describe exemplary embodiments of the present disclosure, rather than to represent the only embodiment in which the present disclosure can be implemented. The following detailed description includes specific details to provide a complete understanding of the present disclosure. However, those skilled in the relevant art know that the present disclosure can be implemented without these specific details.

[0034] In some cases, well-known structures and devices may be omitted, or may be shown in the form of a block diagram based on the core functions of each structure and device in order to prevent ambiguity of the concepts of the present disclosure.

[0035] In the present disclosure, when an element is referred to as being "connected", "combined" or "linked" to another element, it may include an indirect connection relationship between another element and a direct connection relationship. In addition, in the present disclosure, the term "comprising" or "having" specifies the presence of the mentioned features, steps, operations, components and / or elements, but does not exclude the presence or addition of one or more other features, stages, operations, components, elements and / or groups thereof.

[0036] In the present disclosure, terms such as "first", "second", etc. are only used to distinguish one element from another element and are not used to limit the elements, and unless otherwise specified, they do not limit the order or importance between elements, etc. Therefore, within the scope of the present disclosure, the first element in an embodiment may be referred to as the second element in another embodiment, and similarly, the second element in an embodiment may be referred to as the first element in another embodiment.

[0037] The terms used in this disclosure are intended to describe specific embodiments, rather than to limit the claims. As used in the description of the embodiments and the appended claims, the singular form is intended to include the plural form, unless the context clearly indicates otherwise. The term "and / or" used in this disclosure may refer to one of the related enumerated items, or mean that it refers to and includes any and all possible combinations of two or more of them. In addition, unless otherwise stated, the " / " between words in this disclosure has the same meaning as "and / or".

[0038] Examples of the present disclosure can be applied to various wireless communication systems. For example, examples of the present disclosure can be applied to wireless LAN systems. For example, examples of the present disclosure can be applied to wireless LANs based on IEEE 802.11a / g / n / ac / ax standards. In addition, examples of the present disclosure can be applied to wireless LANs based on the newly proposed IEEE 802.11be (or EHT) standard. Examples of the present disclosure can be applied to wireless LANs based on the IEEE802.11be version 2 standard corresponding to the additional enhanced technology of the IEEE 802.11be version 1 standard. In addition, examples of the present disclosure can be applied to wireless LANs based on next-generation standards after IEEE 802.11be. In addition, examples of the present disclosure can be applied to cellular wireless communication systems. For example, it can be applied to cellular wireless communication systems based on long-term evolution (LTE) technology and 5G new radio (NR) technology based on the third generation partnership project (3GPP) standard.

[0039] Hereinafter, technical features of examples to which the present disclosure can be applied will be described.

[0040] Figure 1 A block diagram of a wireless communication device according to an embodiment of the present disclosure is illustrated.

[0041] Figure 1 The first device 100 and the second device 200 illustrated in the figure may be replaced with various terms such as terminal, wireless device, wireless transmit / receive unit (WTRU), user equipment (UE), mobile station (MS), user terminal (UT), mobile subscriber station (MSS), mobile subscriber unit (MSU), subscriber station (SS), advanced mobile station (AMS), wireless terminal (WT) or simple user, etc. In addition, the first device 100 and the second device 200 include an access point (AP), a base station (BS), a fixed station, a node B, a base transceiver system (BTS), a network. It may be replaced with various terms such as an artificial intelligence (AI) system, a roadside unit (RSU), a repeater, a router, a relay and a gateway.

[0042] Figure 1 The devices 100 and 200 illustrated in the example may be referred to as stations (STAs). Figure 1The devices 100 and 200 illustrated in the figure may be referred to by various terms such as a transmitting device, a receiving device, a transmitting STA, and a receiving STA. For example, the STAs 110 and 200 may perform an access point (AP) role or a non-AP role. That is, in the present disclosure, the STAs 110 and 200 may perform the functions of an AP and / or a non-AP. When the STAs 110 and 200 perform the AP function, they may be simply referred to as APs, and when the STAs 110 and 200 perform the non-AP function, they may be simply referred to as STAs. In addition, in the present disclosure, an AP may also be indicated as an AP STA.

[0043] Reference Figure 1 , the first device 100 and the second device 200 can send and receive radio signals through various wireless LAN technologies (e.g., IEEE802.11 series). The first device 100 and the second device 200 may include interfaces for a media access control (MAC) layer and a physical layer (PHY) that conform to the IEEE802.11 standard.

[0044] In addition, in addition to the wireless LAN technology, the first device 100 and the second device 200 may further support various communication standards (e.g., 3GPP LTE series, 5G NR series standards, etc.) technologies. In addition, the device of the present disclosure may be implemented in various devices such as mobile phones, vehicles, personal computers, augmented reality (AR) devices, and virtual reality (VR) devices. In addition, the STA of the present specification may support various communication services such as voice calls, video calls, data communications, autonomous driving, machine type communications (MTC), machine to machine (M2M), device to device (D2D), IoT (Internet of Things), etc.

[0045] The first device 100 may include one or more processors 102 and one or more memories 104, and may further include one or more transceivers 106 and / or one or more antennas 108. The processor 102 may control the memory 104 and / or the transceiver 106, and may be configured to implement the descriptions, functions, processes, suggestions, methods, and / or operational flowcharts included in the present disclosure. For example, the processor 102 may send a wireless signal including the first information / signal through the transceiver 106 after generating the first information / signal by processing the information in the memory 104. In addition, the processor 102 may receive a wireless signal including the second information / signal through the transceiver 106, and then store the information obtained by the signal processing of the second information / signal in the memory 104. The memory 104 may be connected to the processor 102 and may store various information related to the operation of the processor 102. For example, the memory 104 may store software codes including instructions for executing all or part of the processing controlled by the processor 102 or for executing the descriptions, functions, processes, suggestions, methods, and / or operational flowcharts included in the present disclosure. Here, the processor 102 and the memory 104 may be part of a communication modem / circuit / chip designed to implement wireless LAN technology (e.g., IEEE 802.11 series). The transceiver 106 may be connected to the processor 102 and may send and / or receive wireless signals through one or more antennas 108. The transceiver 106 may include a transmitter and / or a receiver. The transceiver 106 may be used in conjunction with an RF (radio frequency) unit. In the present disclosure, a wireless device may refer to a communication modem / circuit / chip.

[0046] The second device 200 may include one or more processors 202 and one or more memories 204, and may further include one or more transceivers 206 and / or one or more antennas 208. The processor 202 may control the memory 204 and / or the transceiver 206, and may be configured to implement the descriptions, functions, processes, suggestions, methods, and / or operation flowcharts included in the present disclosure. For example, the processor 202 may generate third information / signals by processing the information in the memory 204, and then send a wireless signal including the third information / signal through the transceiver 206. In addition, the processor 202 may receive a wireless signal including fourth information / signals through the transceiver 206, and then store information obtained by signal processing of the fourth information / signal in the memory 204. The memory 204 may be connected to the processor 202 and may store various information related to the operation of the processor 202. For example, the memory 204 may store software codes including instructions for executing all or part of the processing controlled by the processor 202 or for executing the descriptions, functions, processes, suggestions, methods, and / or operation flowcharts included in the present disclosure. Here, the processor 202 and the memory 204 may be part of a communication modem / circuit / chip designed to implement wireless LAN technology (e.g., IEEE 802.11 series). The transceiver 206 may be connected to the processor 202 and may send and / or receive wireless signals through one or more antennas 208. The transceiver 206 may include a transmitter and / or a receiver. The transceiver 206 may be used in conjunction with an RF unit. In the present disclosure, a device may refer to a communication modem / circuit / chip.

[0047] In the following, the hardware elements of the apparatus 100, 200 will be described in more detail. Without limitation thereto, one or more protocol layers may be implemented by one or more processors 102, 202. For example, one or more processors 102, 202 may implement one or more layers (e.g., functional layers such as PHY, MAC). One or more processors 102, 202 may generate one or more PDUs (protocol data units) and / or one or more SDUs (service data units) according to the description, function, process, suggestion, method, and / or operation flow chart disclosed in the present disclosure. One or more processors 102, 202 may generate messages, control information, data, or information according to the description, function, process, suggestion, method, and / or operation flow chart disclosed in the present disclosure. One or more processors 102, 202 may generate signals (e.g., baseband signals) including PDUs, SDUs, messages, control information, data, or information according to the functions, processes, suggestions, and / or methods disclosed in the present disclosure to provide them to one or more transceivers 106, 206. One or more processors 102, 202 may receive a signal (e.g., a baseband signal) from one or more transceivers 106, 206 according to the descriptions, functions, processes, suggestions, methods, and / or operational flow charts included in the present disclosure and obtain a PDU, SDU, message, control information, data, or information.

[0048] One or more processors 102, 202 may be referred to as controllers, microcontrollers, microprocessors, or microcomputers. One or more processors 102, 202 may be implemented by hardware, firmware, software, or a combination thereof. For example, one or more ASICs (Application Specific Integrated Circuits), one or more DSPs (Digital Signal Processors), one or more DSPDs (Digital Signal Processing Devices), one or more PLDs (Programmable Logic Devices), or one or more FPGAs (Field Programmable Gate Arrays) may be included in one or more processors 102, 202. The descriptions, functions, processes, suggestions, methods, and / or operational flow charts included in the present disclosure may be implemented using firmware or software, and the firmware or software may be implemented to include modules, processes, functions, and the like. Firmware or software configured to execute the descriptions, functions, processes, suggestions, methods, and / or operational flow charts included in the present disclosure may be included in one or more processors 102, 202, or may be stored in one or more memories 104, 204 and driven by one or more processors 102, 202. The descriptions, functions, processes, suggestions, methods and / or operational flow charts included in the present disclosure may be implemented using firmware or software in the form of codes, instructions and / or instruction sets.

[0049] One or more memories 104, 204 may be connected to one or more processors 102, 202 and may store data, signals, messages, information, programs, codes, instructions, and / or commands in various forms. One or more memories 104, 204 may be configured with ROM, RAM, EPROM, flash memory, hard drive, registers, cache memory, computer-readable storage media, and / or combinations thereof. One or more memories 104, 204 may be located inside and / or outside one or more processors 102, 202. In addition, one or more memories 104, 204 may be connected to one or more processors 102, 202 via various technologies such as wired or wireless connections.

[0050] One or more transceivers 106, 206 may send user data, control information, wireless signals / channels, etc. mentioned in the method and / or operation flow chart of the present disclosure to one or more other devices. One or more transceivers 106, 206 may receive user data, control information, wireless signals / channels, etc. mentioned in the description, function, process, suggestion, method and / or operation flow chart, etc. included in the present disclosure from one or more other devices. For example, one or more transceivers 106, 206 may be connected to one or more processors 102, 202 and may send and receive wireless signals. For example, one or more processors 102, 202 may control one or more transceivers 106, 206 to send user data, control information or wireless signals to one or more other devices. In addition, one or more processors 102, 202 may control one or more transceivers 106, 206 to receive user data, control information or wireless signals from one or more other devices. In addition, one or more transceivers 106, 206 may be connected to one or more antennas 108, 208, and one or more transceivers 106, 206 may be configured to send and receive user data, control information, wireless signals / channels, etc. mentioned in the description, functions, processes, suggestions, methods and / or operation flow charts, etc. included in the present disclosure through one or more antennas 108, 208. In the present disclosure, one or more antennas may be multiple physical antennas or multiple logical antennas (e.g., antenna ports). One or more transceivers 106, 206 may convert received wireless signals / channels, etc. from RF band signals into baseband signals to process received user data, control information, wireless signals / channels, etc. by using one or more processors 102, 202. One or more transceivers 106, 206 may convert user data, control information, wireless signals / channels, etc. processed by using one or more processors 102, 202 from baseband signals into RF band signals. Thus, one or more of the transceivers 106 , 206 may include (analog) oscillators and / or filters.

[0051] For example, one of the STAs 100 and 200 may perform the expected operation of an AP, and the other of the STAs 100 and 200 may perform the expected operation of a non-AP STA. Figure 1 The transceivers 106 and 206 of the present invention may perform transmission and reception operations of signals (e.g., packets or physical layer protocol data units (PPDUs) compliant with IEEE 802.11a / b / g / n / ac / ax / be / bn). In addition, in the present disclosure, operations of various STAs generating transmission / reception signals or performing data processing or calculations on transmission / reception signals in advance may be performed by Figure 1The processors 102 and 202 are executed. For example, examples of operations of generating a transmission / reception signal or performing data processing or calculation for the transmission / reception signal in advance may include: 1) determining / obtaining / configuring / calculating / decoding / encoding bit information of fields (signal (SIG), short training field (STF), long training field (LTF), data, etc.) included in the PPDU; 2) determining / configuring / obtaining time resources or frequency resources (e.g., subcarrier resources) for fields (SIG, STF, LTF, data, etc.) included in the PPDU; 3) determining / configuring / obtaining a specific sequence (e.g., pilot sequence, STF / LTF sequence, additional sequence applied to SIG) for fields (SIG, STF, LTF, data, etc.) included in the PPDU action; 4) power control operations and / or power saving operations applied to STAs; 5) operations related to ACK signal determination / obtaining / configuring / calculating / decoding / encoding, etc. In addition, in the following example, various information used by various STAs to determine / acquire / configure / calculate / decode / encode transmission signals and reception signals (e.g., information related to fields / subfields / control fields / parameters / power, etc.) may be stored in Figure 1 in the memories 104 and 204.

[0052] Hereinafter, a downlink (DL) may mean a link for communication from an AP STA to a non-AP STA, and a DL PPDU / packet / signal may be transmitted and received through the DL. In DL communication, a transmitter may be a part of an AP STA, and a receiver may be a part of a non-AP STA. An uplink (UL) may mean a link for communication from a non-AP STA to an AP STA, and a UL PPDU / packet / signal may be transmitted and received through the UL. In UL communication, a transmitter may be a part of a non-AP STA, and a receiver may be a part of an AP STA.

[0053] Figure 2 is a diagram illustrating an exemplary structure of a wireless LAN system to which the present disclosure can be applied.

[0054] The structure of the wireless LAN system may be composed of a plurality of components. A wireless LAN supporting STA mobility transparent to an upper layer may be provided through the interaction of the plurality of components. A basic service set (BSS) corresponds to a basic building block of a wireless LAN. Figure 2 It is exemplarily shown that two BSSs (BSS1 and BSS2) exist, and two STAs (STA1 and STA2 are included in BSS1, and STA3 and STA4 are included in BSS2) are included as members of each BSS. Figure 2The ellipse representing the BSS in the figure can also be understood as representing the coverage area in which the STAs included in the corresponding BSS maintain communication. This area can be called a basic service area (BSA). When a STA moves outside the BSA, it cannot communicate directly with other STAs in the BSA.

[0055] If you don't consider Figure 2 , the most basic BSS type in the wireless LAN is an independent BSS (IBSS), if the DS is shown in FIG. 1 . For example, an IBSS may have a minimum form containing only two STAs. For example, assuming that other components are omitted, a BSS1 containing only STA1 and STA2 or a BSS2 containing only STA3 and STA4 may correspond to representative examples of IBSSs, respectively. This configuration is possible when STAs can communicate directly without an AP. In addition, in this type of wireless LAN, it is not pre-configured but can be configured when a LAN is needed, and this may be referred to as an ad-hoc network. Since the IBSS does not include an AP, there is no centralized management entity. That is, in the IBSS, STAs are managed in a distributed manner. In the IBSS, all STAs may be composed of mobile STAs, and access to the distributed system (DS) is not allowed, thereby forming a self-contained network.

[0056] The membership of a STA in a BSS can be changed dynamically by turning the STA on or off, entering or exiting a BSS region, etc. In order to become a member of a BSS, a STA can join the BSS using a synchronization process. In order to access all services of the BSS infrastructure, a STA should associate with the BSS. This association can be established dynamically and can include the use of a distributed system service (DSS).

[0057] The direct STA-to-STA distance in a wireless LAN may be limited by PHY performance. In some cases, this distance limitation may be sufficient, but in some cases, communication between STAs at longer distances may be required. A distributed system (DS) can be configured to support extended coverage.

[0058] DS refers to the structure of BSS interconnection. Specifically, Figure 2As shown, the BSS can exist as an extended form of a network composed of multiple BSSs. DS is a logical concept and can be specified by the characteristics of the distributed system medium (DSM). At this point, the wireless medium (WM) and the DSM can be logically separated. Each logical medium is used for different purposes and is used by different components. These media are not limited to being the same, nor are they limited to being different. In this way, the flexibility of the wireless LAN structure (DS structure or other network structure) can be interpreted as multiple media being logically different. That is, the wireless LAN structure can be implemented in various ways, and the corresponding wireless LAN structure can be independently specified by the physical characteristics of each implementation.

[0059] DS can support mobile devices by providing seamless integration of multiple BSSs and providing logical services necessary to address the address leading to the destination. In addition, DS can also include a component called a portal, which is used as a bridge for connection between wireless LAN and other networks (e.g., IEEE 802.X).

[0060] The AP enables access to the DS through the WM for associated non-AP STAs and means an entity that also has STA functionality. Data movement between the BSS and the DS can be performed through the AP. For example, Figure 2 STA2 and STA3 shown in the figure have the function of STA and provide the function of allowing the associated non-AP STA (STA1 and STA4) to access the DS. In addition, since all APs basically correspond to STAs, all APs are addressable entities. The address used by the AP to communicate on the WM is not necessarily the same as the address used by the AP to communicate on the DSM. A BSS composed of an AP and one or more STAs may be referred to as an infrastructure BSS.

[0061] Data sent from one of the STAs associated with the AP to the STA address of the corresponding AP can always be received at the uncontrolled port and can be processed by the IEEE 802.1X port access entity. In addition, when the controlled port is authenticated, the transmitted data (or frame) can be delivered to the DS.

[0062] In addition to the above-mentioned structure of the DS, an extended service set (ESS) may also be configured to provide wide coverage.

[0063] ESS means a network with arbitrary size and complexity consisting of DS and BSS. ESS may correspond to a set of BSSs connected to one DS. However, ESS does not include DS. The ESS network is characterized by being regarded as an IBSS in the logical link control (LLC) layer. The STAs included in the ESS can communicate with each other, and the mobile STA can move from one BSS to another (within the same ESS) transparently for LLC. The APs included in one ESS may have the same service set identifier (SSID). SSID is distinguished from BSSID, which is an identifier of BSS.

[0064] The wireless LAN system does not assume anything about the relative physical location of the BSS, and all of the following forms are possible. The BSS may partially overlap, which is a form commonly used to provide continuous coverage. In addition, the BSS may not be physically connected, and logically, there is no limit on the distance between the BSS. In addition, the BSS may be physically located in the same location, which can be used to provide redundancy. In addition, one (or more than one) IBSS or ESS network may physically exist in the same space as one (or more than one) ESS network. When an ad hoc network operates in a location where an ESS network exists, when physically overlapping wireless networks are configured by different organizations, or when two or more different access and security policies are required in the same location, this may correspond to the form of an ESS network, etc.

[0065] Figure 3 is a diagram for explaining a link establishment process to which the present disclosure can be applied.

[0066] In order for a STA to establish a link with respect to a network and send / receive data, it first discovers the network, performs authentication, establishes association, and needs to perform authentication processing for security. The link establishment processing may also be referred to as a session initiation processing or a session establishment processing. In addition, the discovery, authentication, association, and security establishment processing of the link establishment processing may be collectively referred to as an association processing.

[0067] In step S310, the STA may perform a network discovery operation. The network discovery operation may include a scanning operation of the STA. That is, in order for the STA to access a network, it needs to find a network that it can participate in. The STA should identify compatible networks before participating in a wireless network, and the process of identifying networks present in a specific area is called scanning.

[0068] Scanning schemes include active scanning and passive scanning. Figure 3The network discovery operation including active scanning processing is exemplarily illustrated. In active scanning, the STA performing the scan sends a probe request frame to discover which APs exist around it while the channel moves and waits for a response thereto. The responder sends a probe response frame as a response to the probe request frame to the STA that has sent the probe request frame. Here, the responder may be the STA that last sent a beacon frame in the BSS of the channel being scanned. In the BSS, since the AP sends a beacon frame, the AP becomes the responder, and in the IBSS, the STAs in the IBSS rotate to send beacon frames, so the responder is not constant. For example, a STA that sends a probe request frame on channel 1 and receives a probe response frame on channel 1 may store the BSS-related information included in the received probe response frame, and may move to the next channel (e.g., channel 2), and perform scanning in the same manner (i.e., sending and receiving probe requests / responses on channel 2).

[0069] Although not in Figure 3 , but the scanning operation can be performed in a passive scanning manner. In passive scanning, the STA performing the scan waits for a beacon frame while the channel moves. The beacon frame is one of the management frames defined in IEEE 802.11, and is periodically sent to notify the existence of a wireless network and allow the STA performing the scan to find the wireless network and participate in the wireless network. In the BSS, the AP is used to periodically send beacon frames, and in the IBSS, the STAs within the IBSS rotate to send beacon frames. When the STA performing the scan receives the beacon frame, the STA stores the information of the BSS included in the beacon frame, and records the beacon frame information in each channel while moving to another channel. The STA receiving the beacon frame can store the BSS-related information included in the received beacon frame, move to the next channel, and perform scanning in the next channel in the same manner. Comparing active scanning with passive scanning, the advantage of active scanning is that it has less delay and less power consumption than passive scanning.

[0070] After the STA discovers the network, an authentication process may be performed at step S320. In order to clearly distinguish from the security establishment operation of step S340 to be described later, this authentication process may be referred to as a first authentication process.

[0071] The authentication process includes the following process: the STA sends an authentication request frame to the AP, and in response thereto, the AP sends an authentication response frame to the STA. The authentication frame for authentication request / response corresponds to a management frame.

[0072] The authentication frame includes an authentication algorithm number, an authentication transaction sequence number, a status code, a challenge text, a robust security network (RSN), a limited cycle group, etc. This corresponds to some examples of information that can be included in the authentication request / response frame, and can be replaced with other information, or additional information can also be included.

[0073] The STA may send an authentication request frame to the AP. The AP may determine whether to allow authentication of the corresponding STA based on the information included in the received authentication request frame. The AP may provide the result of the authentication process to the STA via an authentication response frame.

[0074] After the STA is successfully authenticated, an association process may be performed at step S330. The association process includes the following processes: the STA sends an association request frame to the AP, and in response, the AP sends an association response frame to the STA.

[0075] For example, the association request frame may include information related to various capabilities, a beacon listening interval, a service set identifier (SSID), supported rates, supported channels, RSN, a mobile domain, supported operation categories, a traffic indication map broadcast request (TIM broadcast request), interworking service capabilities, etc. For example, the association response frame may include information related to various capabilities, a status code, an association ID (AID), supported rates, an enhanced distributed channel access (EDCA) parameter set, a received channel power indicator (RCPI), a received signal-to-noise ratio indicator (RSNI), a mobile domain, a timeout interval (e.g., an association recovery time), an overlapping BSS scan parameter, a TIM broadcast response, a quality of service (QoS) map, etc. This corresponds to some examples of information that may be included in an association request / response frame, and may be replaced with other information, or may also include additional information.

[0076] After the STA successfully associates with the network, a security establishment process may be performed at step S340. The security establishment process at step S340 may be referred to as an authentication process through a robust security network association (RSNA) request / response, the authentication process at step S320 may be referred to as a first authentication process, and the security establishment process at step S340 may also be referred to simply as an authentication process.

[0077] The security establishment process of step S340 may include, for example, a process of establishing a private key through an Extensible Authentication Protocol over LAN (EAPOL) frame using a four-way handshake. In addition, the security establishment process may be performed according to a security scheme not defined in the IEEE 802.11 standard.

[0078] Figure 4 It is a diagram for explaining a backoff process to which the present disclosure can be applied.

[0079] In a wireless LAN system, the basic access mechanism of the medium access control (MAC) is a carrier sense multiple access with collision avoidance (CSMA / CA) mechanism. The CSMA / CA mechanism is also known as the distributed coordination function (DCF) of the IEEE 802.11 MAC, and basically adopts a "listen before talk" access mechanism. According to this type of access mechanism, before starting to send, the AP and / or STA may perform a clear channel assessment (CCA) of sensing the radio channel or medium during a predetermined time interval (e.g., DCF interframe space (DIFS)). As a result of the sensing, if it is determined that the medium is in an idle state, frame transmission is started through the corresponding medium. On the other hand, if it is detected that the medium is occupied or busy, the corresponding AP and / or STA does not start its own transmission, and a delay period (e.g., a random backoff period) for medium access may be set and frame transmission may be attempted after waiting. By applying a random backoff period, since multiple STAs are expected to attempt frame transmission after waiting for different time periods, conflicts can be minimized.

[0080] In addition, the IEEE 802.11 MAC protocol provides a hybrid coordination function (HCF). HCF is based on DCF and point coordination function (PCF). PCF is a synchronous access method based on polling, and refers to a method in which all receiving APs and / or STAs periodically poll to receive data frames. In addition, HCF has enhanced distributed channel access (EDCA) and HCF controlled channel access (HCCA). EDCA is a contention-based access method that provides data frames to multiple users in a direction, and HCCA uses a non-contention-based channel access method that utilizes a polling mechanism. In addition, HCF includes a medium access mechanism for improving the QoS (quality of service) of a wireless LAN, and QoS data can be sent during a contention period (CP) and a contention-free period (CFP).

[0081] Reference Figure 4, the operation based on the random backoff period will be described. When the occupied / busy medium becomes idle, multiple STAs may attempt to send data (or frames). As a method of minimizing conflicts, each of the STAs may select a random backoff count respectively and attempt to send after waiting for the corresponding time slot time. The random backoff count has a pseudo-random integer value and may be determined as one of the values ​​ranging from 0 to CW. Here, CW is a contention window parameter value. The CW parameter is assigned CWmin as an initial value, but may take a value twice as large in the event of a transmission failure (e.g., when an ACK for a transmitted frame is not received). When the CW parameter value reaches CWmax, data transmission may be attempted while maintaining the CWmax value until data transmission is successful, and when data transmission is successful, the CWmin value is reset. The values ​​of CW, CWmin, and CWmax are preferably set to 2n-1 (n=0, 1, 2, ...).

[0082] When the random backoff process starts, the STA continuously monitors the medium in the backoff slot countdown according to the determined backoff count value. When the medium is monitored for occupancy, it stops the countdown and waits, and restarts the remaining part of the countdown when the medium becomes idle.

[0083] exist Figure 4 In the example of , when the packet to be sent arrives at the MAC of STA 3, STA3 can send the frame immediately after confirming that the medium has been idle for up to DIFS. The remaining STAs monitor and wait for the medium to be occupied / busy. At the same time, the data to be sent can also occur in each of STA1, STA2 and STA5, and when the medium is monitored as idle, each STA waits for up to DIFS, and then the countdown of the backoff slot can be performed according to the random backoff count value selected by each STA. Assume that STA2 selects the minimum backoff count value and STA1 selects the maximum backoff count value. That is, the example illustrates the case where the remaining backoff time of STA5 is shorter than the remaining backoff time of STA1 when STA2 completes the backoff count and starts frame transmission. STA1 and STA5 temporarily stop the countdown and wait when STA2 occupies the medium. When STA2's occupation ends and the medium becomes idle again, STA1 and STA5 wait for DIFS and restart the stopped backoff count. That is, frame transmission can start after counting down the remaining backoff slot for the remaining backoff time. Since the remaining backoff time of STA5 is shorter than that of STA1, STA5 starts frame transmission. The data to be transmitted may also occur in STA4 while STA2 occupies the medium. From the perspective of STA4, when the medium becomes idle, STA4 may wait for DIFS, and then may perform a countdown according to a random backoff count value selected by STA4, and start transmitting frames. Figure 4The example shows a case where the remaining backoff time of STA5 accidentally collides with the random backoff count value of STA4. In this case, a collision may occur between STA4 and STA5. When a collision occurs, neither STA4 nor STA5 receives an ACK, so data transmission fails. In this case, STA4 and STA5 can double the CW value, select a random backoff count value, and perform a countdown. While the medium is occupied due to the transmission of STA4 and STA5, STA1 waits, and when the medium becomes idle, STA1 waits DIFS, and then starts frame transmission after the remaining backoff time has passed.

[0084] As in Figure 4 In the example of , a data frame is a frame for sending data forwarded to a higher layer, and may be sent after a backoff performed after DIFS has passed since the medium became idle. In addition, a management frame is a frame for exchanging management information that is not forwarded to a higher layer, and is sent after a backoff is performed after an IFS such as DIFS or a point coordination function IFS (PIFS). As subtype frames of the management frame, there are beacons, association requests / responses, reassociation requests / responses, probe requests / responses, authentication requests / responses, and the like. A control frame is a frame for controlling access to a medium. As subtype frames of the control frame, there are request to send (RTS), permission to send (CTS), acknowledgement (ACK), power save polling (PS-Poll), block ACK (BlockAck), block ACK request (BlockACKReq), empty data packet announcement (NDP announcement), and trigger, and the like. If the control frame is not a response frame of the previous frame, it is sent after a backoff is performed after DIFS has passed, and if it is a response frame of the previous frame, it is sent without performing a backoff after a short IFS (SIFS). The type and subtype of a frame may be identified by the type field and subtype field in the frame control (FC) field.

[0085] Quality of Service (QoS) STA can perform a backoff performed after arbitration IFS (AIFS) (i.e., AIFS (where i is a value determined by AC)) for the access category (AC) to which the frame belongs, and then can send the frame. Here, the frame that can use AIFS may be a data frame, a management frame, or a control frame instead of a response frame.

[0086] Figure 5 is a diagram for explaining a frame transmission operation based on CSMA / CA to which the present disclosure can be applied.

[0087] As described above, in addition to the physical carrier sensing in which the STA directly senses the medium, the CSMA / CA mechanism also includes virtual carrier sensing. Virtual carrier sensing is intended to compensate for problems such as hidden node problems that may occur in medium access. For virtual carrier sensing, the MAC of the STA can use a network allocation vector (NAV). NAV is a value that indicates to other STAs the remaining time until the medium is available for use by the STA that is currently using or has the right to use the medium. Therefore, the value set to NAV corresponds to the period during which the STA sending the frame plans to use the medium, and during the corresponding period, the STA receiving the NAV value is prohibited from accessing the medium. For example, the NAV can be configured based on the value of the "Duration" field of the MAC header of the frame.

[0088] exist Figure 5 In the example of FIG. 1 , it is assumed that STA1 intends to send data to STA2, and STA3 is in a position to be able to eavesdrop on some or all frames sent and received between STA1 and STA2.

[0089] In order to reduce the possibility of transmission conflicts among multiple STAs in the frame transmission operation based on CSMA / CA, a mechanism using RTS / CTS frames can be applied. Figure 5 In the example of , when STA1's transmission is being performed, as a result of STA3's carrier sensing, it can be determined that the medium is in an idle state. That is, STA1 may correspond to a hidden node with respect to STA3. Alternatively, in Figure 5 In the example of , it can be determined that the carrier sensing result medium of STA3 is in an idle state while the transmission of STA2 is being performed. That is, STA2 may correspond to a hidden node with respect to STA3. By exchanging RTS / CTS frames before performing data transmission and reception between STA1 and STA2, STAs outside the transmission range of one of STA1 or STA2 or STAs outside the carrier sensing range of the transmission from STA1 or STA3 may not attempt to occupy the channel during data transmission and reception between STA1 and STA2.

[0090] Specifically, STA1 can determine whether the channel is being used by carrier sensing. In terms of physical carrier sensing, STA1 can determine the channel occupancy idle state based on the energy level or signal correlation detected in the channel. In addition, in terms of virtual carrier sensing, STA1 can use the network allocation vector (NAV) timer to determine the channel occupancy state.

[0091] When the channel is in an idle state during DIFS, STA1 may send an RTS frame to STA2 after performing backoff. When STA2 receives the RTS frame, STA2 may send a CTS frame to STA1 as a response to the RTS frame after SIFS.

[0092] If STA3 cannot eavesdrop on the CTS frame from STA2 but can eavesdrop on the RTS frame from STA1, STA3 can set the NAV timer for the frame transmission period (e.g., SIFS+CTS frame+SIFS+data frame+SIFS+ACK frame) that is continuously transmitted thereafter using the duration information included in the RTS frame. Alternatively, if STA3 can eavesdrop on the CTS frame from STA2, STA3 can set the NAV timer for the frame transmission period (e.g., SIFS+data frame+SIFS+ACK frame) that is continuously transmitted thereafter using the duration information included in the CTS frame even though STA3 cannot eavesdrop on the RTS frame from STA1. That is, if STA3 can eavesdrop on one or more of the RTS frame or the CTS frame from one or more of STA1 or STA2, STA3 can set the NAV accordingly. When STA3 receives a new frame before the NAV timer expires, STA3 can update the NAV timer using the duration information included in the new frame. STA3 does not attempt channel access until the NAV timer expires.

[0093] When STA1 receives a CTS frame from STA2, STA1 may send a data frame to STA2 after SIFS, starting from the time point when reception of the CTS frame is completed. When STA2 successfully receives the data frame, STA2 may send an ACK frame to STA1 after SIFS as a response to the data frame. When the NAV timer expires, STA3 may determine whether the channel is being used by carrier sensing. When STA3 determines that the channel is not being used by other terminals during the DIFS period after the NAV timer expires, STA3 may attempt channel access after the contention window (CW) according to the random backoff has passed.

[0094] Figure 6 is a diagram for explaining an example of a frame structure used in a WLAN system to which the present disclosure can be applied.

[0095] With the help of instructions or primitives (meaning a set of instructions or parameters) from the MAC layer, the PHY layer can prepare a MAC PDU (MPDU) to be transmitted. For example, when a command requesting the PHY layer to start transmitting is received from the MAC layer, the PHY layer switches to a transmission mode, and configures information (e.g., data) provided from the MAC layer in the form of a frame and transmits it. In addition, when the PHY layer detects a valid preamble of a received frame, the PHY layer monitors the header of the preamble and transmits a command notifying the start of reception of the PHY layer to the MAC layer.

[0096] In this manner, information transmission / reception in the wireless LAN system is performed in the form of a frame, and for this purpose, a PHY layer protocol data unit (PPDU) format is defined.

[0097] The basic PPDU may include a short training field (STF), a long training field (LTF), a signal (SIG) field, and a data (Data) field. The most basic PPDU format (e.g., Figure 7 The non-HT (high throughput) shown in the figure may consist of only the legacy-STF (L-STF), the legacy-LTF (L-LTF), the legacy-SIG (L-SIG) field and the data field. In addition, depending on the type of PPDU format (e.g., HT mixed format PPDU, HT greenfield format PPDU, VHT (very high throughput) PPDU, etc.), additional (or different types of) RL-SIG, U-SIG, non-legacy SIG field, non-legacy STF, non-legacy LTF (i.e., xx-SIG, xx-STF, xx-LTF (e.g., xx is HT, VHT, HE, EHT, etc.)) and the like may be included between the L-SIG field and the data field.

[0098] STF is a signal used for signal detection, automatic gain control (AGC), diversity selection, precise time synchronization, etc., and LTF is a signal used for channel estimation and frequency error estimation. STF and LTF can be called signals for synchronization and channel estimation of the OFDM physical layer.

[0099] The SIG field may include various information related to the transmission and reception of the PPDU. For example, the L-SIG field consists of 24 bits, and the L-SIG field may include a 4-bit rate field, a 1-bit reserved bit, a 12-bit length field, a 1-bit parity field, and a 6-bit tail field. The RATE field may include information about the modulation and coding rate of the data. For example, the 12-bit length field may include information about the length or duration of the PPDU. For example, the value of the 12-bit length field may be determined based on the type of the PPDU. For example, for non-HT, HT, VHT, or EHT PPDUs, the value of the length field may be determined as a multiple of 3. For example, for HEPPDUs, the value of the length field may be determined as a multiple of 3+1 or a multiple of 3+2.

[0100] The data field may include a service (SERVICE) field, a physical layer service data unit (PSDU) and a PPDU tail bit, and may also include padding bits if necessary. Some bits of the service field may be used for synchronization of the descrambler at the receiving end. The PSDU corresponds to the MAC PDU defined in the MAC layer and may include data generated / used in the upper layer. The PPDU tail bit may be used to return the encoder to the 0 state. The padding bit may be used to adjust the length of the data field in predetermined units.

[0101] MAC PDU is defined according to various MAC frame formats, and a basic MAC frame consists of a MAC header, a frame body, and a frame check sequence (FCS). A MAC frame may consist of a MAC PDU and be transmitted / received through a PSDU of a data portion of a PPDU format.

[0102] The MAC header includes a frame control field, a duration / ID field, an address field, etc. The frame control field may include control information required for frame transmission / reception. The duration / ID field may be set to the time for transmitting the corresponding frame, etc. For details of the sequence control, QoS control, and HT control subfields of the MAC header, refer to the IEEE 802.11 standard document.

[0103] The null data PPDU (NDP) format refers to a PPDU format that does not include a data field. In other words, NDP refers to a frame format that includes a PPDU preamble (i.e., L-STF, L-LTF, L-SIG fields and additional non-legacy SIG, non-legacy STF, non-legacy LTF (if present)) of a general PPDU format and does not include the remaining part (i.e., the data field).

[0104] Figure 7 is a diagram illustrating an example of a PPDU defined in the IEEE 802.11 standard to which the present disclosure can be applied.

[0105] In standards such as IEEE 802.11a / g / n / ac / ax, various types of PPDUs have been used. The basic PPDU format (IEEE 802.11a / g) includes L-LTF, L-STF, L-SIG, and data fields. The basic PPDU format may also be referred to as a non-HT PPDU format (such as Figure 7 (as shown in (a)).

[0106] Compared to the basic PPDU format, the HT PPDU format (IEEE 802.11n) additionally includes HT-SIG, HT-STF, and HT-LFT fields. Figure 7The HT PPDU format shown in (b) may be referred to as an HT mixed format. In addition, an HT greenfield format PPDU may be defined, and this corresponds to a format consisting of HT-GF-STF, HT-LTF1, HT-SIG, one or more HT-LTFs, and a data field, excluding L-STF, L-LTF, and L-SIG (not shown).

[0107] Compared to the basic PPDU format, an example of the VHT PPDU format (IEEE 802.11ac) additionally includes VHTSIG-A, VHT-STF, VHT-LTF, and VHT-SIG-B fields (eg, Figure 7 (as shown in (c)).

[0108] Compared to the basic PPDU format, an example of the HE PPDU format (IEEE 802.11ax) additionally includes a repeated L-SIG (RL-SIG), HE-SIG-A, HE-SIG-B, HE-STF, HE-LTF, a packet extension (PE) field (such as Figure 7 (d) of the HE PPDU format). Some fields may be excluded or their lengths may vary according to the detailed example of the HE PPDU format. For example, the HE-SIG-B field is included in the HE PPDU format for multi-user (MU), and the HE-SIG-B is not included in the HE PPDU format for single user (SU). In addition, the HE trigger-based (TB) PPDU format does not include the HE-SIG-B, and the length of the HE-STF field may vary to 8μs. The extended range (HE ER) SU PPDU format does not include the HE-SIG-B field, and the length of the HE-SIG-A field may vary to 16μs. For example, the RL-SIG may be configured to be the same as the L-SIG. Based on the presence of the RL-SIG, the receiving STA may know that the received PPDU is a HE PPDU or an EHT PPDU, which will be described later.

[0109] The EHT PPDU format may include Figure 7 (e) EHT MU (multi-user) and Figure 7 The EHT TB (trigger-based) PPDU in (f) of FIG. The EHT PPDU format is similar to the HE PPDU format in that it includes the RL-SIG following the L-SIG, but may include the U (Universal)-SIG, the EHT-SIG, the EHT-STF, and the EHT-LTF following the RL-SIG.

[0110] Figure 7The EHT MU PPDU in (e) corresponds to a PPDU carrying one or more data (or PSDU) for one or more users. That is, the EHT MU PPDU can be used for both SU transmission and MU transmission. For example, the EHT MU PPDU can correspond to a PPDU for one receiving STA or multiple receiving STAs.

[0111] Compared with EHT MU PPDU, Figure 7 The EHT TB PPDU in (f) omits the EHT-SIG. A STA that receives a trigger for UL MU transmission (eg, a trigger frame or a triggered response schedule (TRS)) may perform UL transmission based on the EHT TB PPDU format.

[0112] The L-STF, L-LTF, L-SIG, RL-SIG, U-SIG (Universal Signal), EHT-SIG fields may be coded and modulated so that even legacy STAs may attempt to demodulate and decode, and may be mapped based on a determined subcarrier frequency interval (e.g., 312.5kHz). These may be referred to as pre-EHT modulation fields. Next, the EHT-STF, EHT-LTF, data, PE fields may be coded and modulated so that they may be demodulated and decoded by a STA that successfully decodes a non-legacy SIG (e.g., U-SIG and / or EHT-SIG) and obtains the information included in the field, and may be mapped based on a determined subcarrier frequency interval (e.g., 78.125kHz). These may be referred to as EHT modulation fields.

[0113] Similarly, in the HE PPDU format, the L-STF, L-LTF, L-SIG, RL-SIG, HE-SIG-A, and HE-SIG-B fields may be referred to as pre-HE modulation fields, and the HE-STF, HE-LTF, data, and PE fields may be referred to as HE modulation fields. In addition, in the VHT PPDU format, the L-STF, L-LTF, L-SIG, and VHT-SIG-A fields may be referred to as non-VHT modulation fields, and the VHT STF, VHT-LTF, VHT-SIG-B, and data fields may be referred to as VHT modulation fields.

[0114] Included in Figure 7The U-SIG in the EHT PPDU format may be configured based on, for example, two symbols (e.g., two consecutive OFDM symbols). Each symbol (e.g., OFDM symbol) used for the U-SIG may have a duration of 4 μs, and the U-SIG may have a total duration of 8 μs. Each symbol of the U-SIG may be used to send 26 bits of information. For example, each symbol of the U-SIG may be sent and received based on 52 data tones and 4 pilot tones.

[0115] The U-SIG may be constructed in units of 20 MHz. For example, if an 80 MHz PPDU is constructed, the U-SIG may be duplicated. That is, the same 4 U-SIGs may be included in the 80 MHz PPDU. A PPDU with a bandwidth exceeding 80 MHz may include a different U-SIG.

[0116] For example, A uncoded bits may be sent via U-SIG, the first symbol of U-SIG (e.g., U-SIG-1 symbol) may send the first X bits of information out of a total of A bits of information, and the second symbol of U-SIG (e.g., U-SIG-2 symbol) may send the remaining Y bits of information out of a total of A bits of information. The A bits of information (e.g., 52 uncoded bits) may include a CRC field (e.g., a 4-bit long field) and a tail field (e.g., a 6-bit long field). For example, the tail field may be used to terminate the trellis structure of the convolutional decoder and may be set to 0.

[0117] The bit information sent through U-SIG can be divided into version-independent bits and version-dependent bits. For example, U-SIG can be included in Figure 7 In a new PPDU format not shown in the EHT PPDU format (e.g., UHR PPDU format), and may be included in the format of the U-SIG field included in the EHT PPDU format and the format of the U-SIG field included in the UHR PPDU format, the version-independent bits may be the same, and some or all of the version-related bits may be different.

[0118] For example, the size of the version-independent bit of the U-SIG may be fixed or variable. The version-independent bit may be assigned only to the U-SIG-1 symbol, or to both the U-SIG-1 symbol and the U-SIG-2 symbol. The version-independent bit and the version-dependent bit may be referred to by various names, such as a first control bit and a second control bit.

[0119] For example, the version-independent bits of the U-SIG may include a 3-bit physical layer version identifier (PHY version identifier), and this information may indicate the PHY version (e.g., EHT, UHR, etc.) of the transmitted / received PPDU. The version-independent bits of the U-SIG may include a 1-bit UL / DL flag field. The first value of the 1-bit UL / DL flag field is related to UL communication, and the second value of the UL / DL flag field is related to DL communication. The version-independent bits of the U-SIG may include information about the length of a transmit opportunity (TXOP) and information about a BSS color ID.

[0120] For example, the version-related bits of the U-SIG may include information directly or indirectly indicating the type of the PPDU (eg, SU PPDU, MU PPDU, TB PPDU, etc.).

[0121] Information required for PPDU transmission and reception may be included in the U-SIG. For example, the U-SIG may also include information about bandwidth, information about an MCS technology applied to a non-legacy SIG (e.g., EHT-SIG or UHR-SIG, etc.), information indicating whether a DCM (dual carrier modulation) technology (e.g., a technology for achieving an effect similar to frequency diversity by reusing the same signal on two subcarriers) is applied to the non-legacy SIG, information about the number of symbols used for the non-legacy SIG, and information about whether the non-legacy SIG is generated across the entire frequency band.

[0122] Some of the information required for PPDU transmission and reception may be included in the U-SIG and / or the non-legacy SIG (e.g., EHT-SIG or UHR-SIG, etc.). For example, information about the type of non-legacy LTF / STF (e.g., EHT-LTF / EHT-STF or UHR-LTF / UHR-STF, etc.), information about the length of the non-legacy LTF and the CP (cyclic prefix) length, information about the GI (guard interval) applicable to the non-legacy LTF, information about preamble puncturing applicable to the PPDU, information about resource unit (RU) allocation, etc. may be included only in the U-SIG, only in the non-legacy SIG, or may be indicated by a combination of information included in the U-SIG and information included in the non-legacy SIG.

[0123] Preamble puncturing may indicate the transmission of a PPDU in which there is no signal in one or more frequency units in the bandwidth of the PPDU. For example, the size of the frequency unit (or the resolution of the preamble puncturing) may be defined as 20 MHz, 40 MHz, etc. For example, preamble puncturing may be applied to a PPDU bandwidth of a predetermined size or greater.

[0124] exist Figure 7In the example of , non-legacy SIGs such as HE-SIG-B and EHT-SIG may include control information for receiving STAs. The non-legacy SIG may be transmitted on at least one symbol, and one symbol may have a length of 4 μs. Information about the number of symbols used for the EHT-SIG may be included in a previous SIG (eg, HE-SIG-A, U-SIG, etc.).

[0125] Non-legacy SIGs such as HE-SIG-B and EHT-SIG may include a common field and a user-specific field. The common field and the user-specific field may be encoded separately.

[0126] In some cases, the common field may be omitted. For example, in a compressed mode that does not apply OFDMA (Orthogonal Frequency Division Multiple Access), the common field may be omitted, and multiple STAs may receive the PPDU (e.g., the data field of the PPDU) through the same frequency band. In a non-compressed mode that applies OFDMA, multiple users may receive the PPDU (e.g., the data field of the PPDU) through different frequency bands.

[0127] The number of user-specific fields may be determined based on the number of users. A user block field may include up to two user fields. Each user field may be associated with a MU-MIMO allocation or may be associated with a non-MU-MIMO allocation.

[0128] The common field may include a CRC bit and a tail bit, and the length of the CRC bit may be determined to be 4 bits, and the length of the tail bit may be determined to be 6 bits and set to 000000. The common field may include RU allocation information. The RU allocation information may include information about the positions of RUs to which multiple users (ie, multiple receiving STAs) are assigned.

[0129] RU can include multiple subcarriers (or tones). RU can be used when sending signals to multiple STAs based on OFDMA technology. In addition, RU can be defined even when sending signals to one STA. Resources can be allocated to non-traditional STF, non-traditional LTF and data fields in units of RU.

[0130] The RU of applicable size may be defined according to the PPDU bandwidth. The RU may be defined identically or differently for the applied PPDU format (e.g., HEPPDU, EHT PPDU, UHR PPDU, etc.). For example, in the case of an 80MHz PPDU, the RU layout of the HEPPDU and EHT PPDU may be different. The applicable RU size, the number of RUs and RU positions, the DC (direct current) subcarrier positions and numbers, the empty subcarrier positions and numbers, the guard subcarrier positions and numbers, etc. for each PPDU bandwidth may be referred to as a tone plan. For example, a tone plan for high bandwidth may be defined in the form of multiple iterations of a low bandwidth tone plan.

[0131] RUs of various sizes may be defined as 26-tone RUs, 52-tone RUs, 106-tone RUs, 242-tone RUs, 484-tone RUs, 996-tone RUs, 2×996-tone RUs, 3×996-tone RUs, etc. MRUs (multi-RUs) are different from multiple individual RUs and correspond to a group of subcarriers consisting of multiple RUs. For example, one MRU may be defined as 52+26 tones, 106+26 tones, 484+242 tones, 996+484 tones, 996+484+242 tones, 2×996+484 tones, 3×996 tones, or 3×996+484 tones. In addition, the multiple RUs constituting one MRU may or may not be continuous in the frequency domain.

[0132] The specific size of the RU may be reduced or expanded. Therefore, the specific size of each RU in the present disclosure (i.e., the number of corresponding tones) is not restrictive but illustrative. In addition, in the present disclosure, within a predetermined bandwidth (e.g., 20 MHz, 40 MHz, 80 MHz, 160 MHz, 320 MHz ...), the number of RUs may vary according to the RU size.

[0133] Figure 7 The names of each field in the PPDU format are exemplary, and the scope of the present disclosure is not limited by these names. In addition, the examples of the present disclosure can be applied to Figure 7 The PPDU format shown in Figure 7 A new PPDU format that excludes some fields and / or adds some fields.

[0134] Figure 8 is a diagram illustrating an exemplary format of a trigger frame to which the present disclosure can be applied.

[0135] The trigger frame may allocate resources for one or more TB PPDU transmissions and may request TB PPDU transmissions. The trigger frame may also include other information required by the STA that sends the TB PPDU in response to the trigger frame. The trigger frame may include a common information field and a user information list field in the frame body.

[0136] The common information field may include information common to one or more TB PPDU transmissions requested by the trigger frame, such as trigger type, UL length, presence of subsequent trigger frames (e.g., more TFs), presence of required channel sensing (CS), ULBW (bandwidth), etc. Figure 8 The EHT variant common information field format is exemplarily shown.

[0137] The 4-bit Trigger Type subfield may have a value from 0 to 15. Among these values, values ​​0, 1, 2, 3, 4, 5, 6, and 7 of the Trigger Type subfield are defined to correspond to Basic, Beamforming Report Poll (BFRP), Multi-User Block Acknowledgement Request (MU-BAR), Multi-User Request to Send (MU-RTS), Buffer Status Report Poll (BSRP), Multicast with Retry (GCR) MU-BAR, Bandwidth Query Report Poll (BQRP), and NDP Feedback Report Poll (NFRP), respectively, and values ​​8 to 15 are defined as reserved.

[0138] Among the common information, the trigger-related common information subfield may include information selectively included based on the trigger type.

[0139] A special user information field may be included in the trigger frame. The special user information field does not contain user-specific information, but contains extended common information that is not provided in the common information field.

[0140] A user information list contains zero or more user information fields. Figure 8 The EHT variant user information field format is exemplarily shown.

[0141] The AID12 subfield basically indicates that it is a user information field for the STA with the corresponding AID. In addition, if the AID12 field has a predetermined specific value, it can be used for other purposes, such as allocating a random access (RA)-RU, or configured in the form of a special user information field. The special user information field is a user information field that does not include user-specific information but includes extended public information that is not provided in the public information field. For example, the special user information field can be identified by the AID12 value 2007, and the special user information field flag subfield in the public information field can indicate whether the special user information field is included.

[0142] The RU Allocation subfield may indicate the size and location of the RU / MRU. For this purpose, the RU Allocation subfield may be interpreted together with the PS160 (Primary / Secondary 160 MHz) subfield of the User Information field, the UL BW subfield of the Common Information field, and the like.

[0143] Triggered TXOP sharing procedure for multiple peer-to-peer (P2P) communications

[0144] Triggering the TXOP sharing procedure may allow an AP to allocate a portion of its TXOP to an associated non-AP STA for transmitting one or more non-TB PPDUs.

[0145] A TXOP may correspond to a duration during which a specific QoS STA (eg, an AP STA and / or a non-AP STA) has the right to initiate a frame exchange sequence over a wireless medium (WM). For example, a TXOP may be defined by a start time and a maximum duration.

[0146] When a TXOP sharing mode subfield related to triggering a TXOP sharing mode is defined in a MU-RTS frame and a value of the subfield is not 0, the frame may be referred to as a MU-RTS TXOP sharing (TXS) trigger frame.

[0147] For example, the TXOP Sharing Mode subfield may be encoded as follows.

[0148] If a value of the TXOP Sharing Mode subfield of the MU-RTS frame is 0, it corresponds to a MU-RTS that does not initiate a MU-RTS TXOP sharing procedure.

[0149] If the value of the TXOP Sharing Mode subfield of the MU-RTS frame is 1, it corresponds to a MU-RTS initiating a MU-RTS TXOP sharing procedure, in which the scheduled STA may only send MPDUs addressed to its associated AP.

[0150] If the value of the TXOP Sharing Mode subfield of the MU-RTS frame is 2, it corresponds to a MU-RTS that initiates a MU-RTS TXOP sharing procedure, which enables a scheduled STA to send an MPDU addressed to its associated AP or to another STA.

[0151] A value 3 of the TXOP Sharing Mode subfield of the MU-RTS frame may be defined as a reserved value.

[0152] Specifically, according to triggered TXOP sharing mode 1, the AP may send a MU-RTS TXS trigger frame to allocate time for the STA to send a non-TB PPDU to the AP, and the STA may respond thereto.

[0153] According to triggered TXOP sharing mode 2, the AP may send a MU-RTS TXS trigger frame to allocate time for the STA to send a non-TB PPDU to other STAs or the AP, and the STA may respond to this. In triggered TXOP sharing mode 2, the transmission of a STA to other STAs may be referred to as peer-to-peer (P2P) transmission.

[0154] A STA that uses information from a received MU-RTS TXS Trigger frame as the latest basis for its Network Allocation Vector (NAV) update shall not reset its NAV after the NAV Timeout Timer expires unless it receives a CF-End frame that meets the conditions for TXOP truncation.

[0155] NAV is maintained by each STA and is an indicator of a time period during which the STA does not initiate transmission on the wireless medium (WM), regardless of whether the clear channel assessment (CCA) function of the STA senses that the WM is busy. For example, the expected channel occupancy time may be indicated by duration information in a frame (e.g., RTS / CTS frame) exchanged between a transmitting STA and a receiving STA, and the remaining STAs (e.g., third-party STAs) other than the transmitting STA and the receiving STA may set a NAV timer corresponding to the indicated time period and may not perform transmission on the WM until the value of the NAV timer expires (or becomes 0).

[0156] After sending the CTS frame requested by the MU-RTS TXS trigger frame received from the AP to which the STA is associated, the STA may ignore the NAV set by the AP within the time allocation signaled in the MU-RTS TXS trigger frame. That is, if the NAV is set, the wireless medium is considered busy or no transmission is initiated, so in order to allow transmission by the STA that has been allocated / shared the AP's TXOP during the triggered TXOP sharing process, the STA may ignore the NAV set by the AP.

[0157] Fig. 9 is a diagram for explaining an example of a triggered TXOP sharing procedure to which the present disclosure may be applied.

[0158] Fig. 9 The example corresponds to an example of triggering TXOP sharing mode 2. That is, it is assumed that the value of the TXOP sharing mode subfield of the MU-RTS TXS trigger frame sent by the AP to the non-AP STA1 is set to 2.

[0159] Here, the MU-RTS TXS trigger frame sent by the AP to the non-AP STA1 may include time allocation information.

[0160] For example, the user information field format of the MU-RTS TXS trigger frame may include an AID12 subfield, an RU allocation subfield, an allocation duration subfield, a PS160 subfield, and a reserved bit.

[0161] Here, the AID12 subfield corresponds to the identification information of the STA, and the allocation duration subfield may indicate the duration allocated to the corresponding STA. At this time, the corresponding duration may be indicated in units of 16us. In this regard, with respect to STA1 (ie, non-AP STA), the corresponding duration may be applied from the time when the indication primitive (eg, PHY-RXEND. indication primitive) of the physical layer of the PPDU including the MU-RTS TXS trigger frame is generated.

[0162] STA1 may send a CTS frame in response to a MU-RTS TXS trigger frame from the AP, and transmit data (i.e., P2P transmission) to STA2 during the time allocated by the MU-RTS TXS trigger frame (corresponding to a portion of the AP's TXOP) and receive a block ACK. When the time allocated by the MU-RTS TXS trigger frame expires (e.g., after PIFS from the expiration of the allocated time), the AP may perform transmission during its TXOP (e.g., data transmission to another STA (STA3)). Although Fig.15 Not shown in the figure, STA1 may also send frames to the AP during the time allocated by the MU-RTS TXS trigger frame.

[0163] Regarding the above process, an AP (eg, an EHT AP) in an existing wireless LAN system may allocate time to only one STA for P2P transmission by using only one user information field in the MU-RTSTXS trigger frame.

[0164] However, in order to support the situation where multiple STAs perform P2P transmission, the above-mentioned triggered TXOP sharing process needs to be modified. Therefore, the present disclosure proposes a process (ie, a frame sequence and time allocation method) for supporting P2P transmission of multiple STAs.

[0165] Fig.10 is a diagram for explaining an operation of an STA in a triggered TXOP sharing procedure according to the present disclosure.

[0166] In step S1010 , the STA may receive a trigger frame related to sharing of the TXOP from the AP.

[0167] For example, the STA may be a non-AP STA, a STA associated with an AP, or a STA within the coverage of a Basic Service Set (BSS) to which the AP belongs.

[0168] Here, the trigger frame may include a common information field and a plurality of user information fields for a plurality of STAs including a corresponding STA.

[0169] For example, the trigger frame in step S1010 may be a trigger frame defined to allocate a duration related to TXOP sharing to multiple STAs. That is, it may be defined to send the trigger frame to multiple STAs.

[0170] In step S1020 , the STA may send a response frame to the trigger frame to the AP.

[0171] For example, the trigger frame in step S1010 may correspond to a multi-user request to send (MU-RTS) TXOP sharing (TXS) trigger frame, and the response frame in step S1020 may correspond to a clear to send (CTS) frame for the MU-RTS TXS trigger frame.

[0172] In this regard, the timing of the duration allocated to the corresponding STA within the TXOP of the AP may be identified based on the order of the user information field for the corresponding STA among a plurality of user information fields included in the trigger frame.

[0173] For example, if one or more user information fields for one or more other STAs included in the plurality of STAs exist before the user information field for the corresponding STA, the timing of the duration allocated to the corresponding STA may be located after the sum of the one or more durations allocated to the one or more other STAs. In this case, the corresponding STA may (sequentially) decode the one or more user information fields for the one or more other STAs to obtain the sum of the one or more durations.

[0174] In addition, the STA may perform transmission of a frame addressed to another STA in the duration allocated thereto (e.g., P2P transmission). In this case, the TXOP Shared Mode subfield included in the Common Information field of the trigger frame may be set to a value (e.g., a value of 2) indicating a TXOP shared mode in which a time is allocated to transmit a frame addressed to another STA from the STA.

[0175] Additionally or alternatively, a user information field for another STA included in the multiple STAs may be located before the user information field for the corresponding STA, and there may be a TXOP return by another STA. Here, the TXOP return may mean a process performed for the AP for the purpose of terminating the time allocation when all transmissions are completed within the duration allocated to the STA. In this case, the STA may receive an additional frame from the AP that triggers the duration allocation within the TXOP. Here, the frame may correspond to at least one of a control frame (e.g., a MU-RTS TXS frame, an RTS frame, etc.), a quality of service (QoS) data frame, or a QoS empty frame.

[0176] Additionally or alternatively, the user information field for another STA included in the multiple STAs may be located before the user information field for the corresponding STA, and there may be no transmission of a response frame for the trigger frame by another STA. That is, it may happen that some STAs among the multiple STAs that have received the corresponding trigger frame do not send a response frame. In this case, the STA may receive an additional frame from the AP that triggers the duration allocation within the TXOP. Here, the frame may correspond to at least one of a control frame (e.g., a MU-RTS TXS frame, an RTS frame, etc.), a QoS data frame, or a QoS empty frame.

[0177] Additionally or alternatively, a user information field for another STA included in the multiple STAs may be located before a user information field for the corresponding STA, and in order to prevent a conflict, a case where the AP determines whether the channel is in an idle (IDLE) state at the end of the duration allocated to the other STA may be considered. If the channel is in an IDLE state, the STA may receive an additional frame from the AP that triggers the duration allocation within the TXOP after the PIFS based on the end time. Here, the frame may correspond to at least one of a control frame (e.g., a MU-RTS TXS frame, an RTS frame, etc.), a QoS data frame, or a QoS empty frame.

[0178] In addition, various methods for signaling a TXOP sharing mode for allocating time to multiple STAs based on multiple user information fields included in the above-mentioned single trigger frame may be considered. For example, in order to indicate the TXOP sharing mode, the TXOP sharing mode subfield included in the common information field may be set to a value indicating the TXOP sharing mode for allocating time to multiple STAs based on multiple user information fields. Alternatively, with respect to indicating the TXOP sharing mode, the common information field may include specific 1-bit information for indicating the TXOP sharing mode for allocating time to multiple STAs based on multiple user information fields.

[0179] Fig.10The method performed by STA described in the example of Figure 1 The first device (100) performs. For example, Figure 1 One or more processors (102) of the first device (100) may be configured to receive a trigger frame related to sharing of a TXOP from an AP (200) through one or more transceivers (106) and send a response frame to the trigger frame to the AP (200).

[0180] In addition, the one or more processors (102) may be configured to identify a time point of the duration allocated to the first device (100) based on the order of the user information field for the first device (100) among the plurality of user information fields included in the trigger frame. For example, if there are one or more user information fields for one or more other STAs before the user information field for the first device (100), the one or more processors (102) may be configured to decode the one or more user information fields for the one or more other STAs to calculate the sum of the durations allocated to the one or more other STAs. Based on this, the one or more processors (102) may be configured to confirm that the time point of the duration allocated to the first device (100) is located after the sum of the durations calculated based on the reception of the trigger frame.

[0181] Additionally, the one or more processors (102) may be configured to transmit, via the one or more transceivers (106), a frame or non-TBPPDU transmission addressed to another STA to the AP (200) during a time period allocated for the first device (100) within the TXOP.

[0182] In addition, one or more memories (104) of the first device (100) may store instructions for executing the operation when executed by one or more processors (102). Fig.10 Examples or instructions of the methods described in the examples described below.

[0183] Fig.11 is a diagram for explaining an operation of an AP in a triggered TXOP sharing procedure according to the present disclosure.

[0184] In step S1110 , the AP may send a trigger frame related to sharing of TXOP to multiple STAs.

[0185] For example, the multiple STAs may be non-AP STAs, or may be STAs associated with an AP, or STAs within the coverage of a basic service set (BSS) to which the AP belongs.

[0186] Here, the trigger frame may include a common information field and a plurality of user information fields for a plurality of STAs including a corresponding STA.

[0187] For example, the trigger frame in step S1110 may be a trigger frame defined to allocate a duration related to TXOP sharing to a plurality of STAs.

[0188] In step S1120 , the AP may receive a response frame to the trigger frame from one or more STAs among the plurality of STAs.

[0189] In this regard, the timing of the duration allocated to the corresponding STA within the TXOP of the AP may be determined based on the order of the user information field for the corresponding STA among a plurality of user information fields included in the trigger frame.

[0190] exist Fig.11 In the example, the characteristics of the transmission and reception of trigger frames, response frames, TXOP sharing mode and additional frames are as follows: Fig.10 The features described in the examples are the same, so redundant descriptions are omitted.

[0191] Fig.11 The method performed by the AP described in the example may be performed by Figure 1 The second device (200) is executed. For example, Figure 1 One or more processors (202) of the second device (200) may be configured to send a trigger frame related to sharing of a TXOP to a plurality of STAs (100) through one or more transceivers (206), and receive a response frame to the trigger frame from one or more STAs (100) among the plurality of STAs (100).

[0192] In addition, the one or more processors (202) may be configured to determine a time point in the duration allocated to each STA (100) based on the order of the user information field relative to the plurality of user information fields when generating the trigger frame. For example, the one or more processors (202) may be configured to sequentially encode the plurality of user information fields for the plurality of STAs to generate the trigger frame.

[0193] In addition, one or more memories (204) of the second device (200) may store instructions for executing the operation when executed by one or more processors (202). Fig.11 Examples or commands of the methods described in the examples described below.

[0194] In the following, reference will be made to Fig. 9 , Fig.10 and Fig.11 A more detailed example of the present disclosure is described.

[0195] In the present disclosure, for the sake of clarity of explanation, STAs (eg, Fig. 9 The non-APSTA1 in is called P2P TX STA, and the ... P2P TX STA Fig. 9 The STA that receives the frame from the non-AP STA2) in the P2P-RX STA is referred to as a P2P-RX STA. However, the scope of the present disclosure is not limited by these names. In addition, in the following description, a STA that is not designated as a non-AP or AP may correspond to an AP STA or a non-AP STA.

[0196] Implementation Method 1

[0197] The present embodiment relates to a method for supporting P2P transmission of multiple STAs by allocating time to each STA using multiple user information fields corresponding to multiple STAs in one MU-RTS TXS trigger frame.

[0198] Specifically, in order to extend the triggered TXOP sharing process to multiple users, a method of allocating time by allocating a user information field to each of multiple STAs through a MU-RTS TXS trigger frame can be applied. In this case, the STA that has received the MU-RTS TXS trigger frame (ie, its own user information field) can send a CTS frame at the same time.

[0199] At this time, the STAs need to know exactly the time they are allocated to perform non-TB PPDU transmission or P2P transmission to the AP.

[0200] Below, a specific method for indicating a duration allocated to each STA based on a user information field is described.

[0201] As described above, in order to allocate time to a plurality of STAs (ie, a plurality of users), a plurality of user information fields may be present / included in the user information list field of the MU-RTS TXS trigger frame.

[0202] In this case, each user information field is defined to allocate time to each STA, and the time can be calculated in sequence from the first allocated user information field to the last user information field. That is, the duration allocated to each STA can be indicated based on the order of the user information fields included in the user information list field.

[0203] At this time, each STA can confirm / identify the start point of the duration allocated thereto by adding the time of the user information field located / existing in front of its own user information field.

[0204] Fig.12is a diagram for explaining an example of a triggered TXOP sharing procedure according to an example of the present disclosure.

[0205] Reference Fig.12 , the AP may send a MU-RTS TXS trigger frame with the TXOP sharing mode set to 2 to multiple STAs (ie, STA1, STA2, STA3) corresponding to the P2P TX STA. Fig.12 The AP in may correspond to an AP in an existing wireless LAN system (eg, an EHT AP) or an AP in a next-generation wireless LAN system (eg, a UHR AP, a next wifi AP, etc.).

[0206] Here, the MU-RTS TXS trigger frame may include a common information field and a user information list field, and the user list information field may include a plurality of user information fields for a plurality of STAs.

[0207] Specifically, the user information list field may include a first user information field (user information field #1) for allocating a T_1 duration to STA1, a second user information field (user information field #2) for allocating a T_2 duration to STA2, and a third user information field (user information field #3) for allocating a T_3 duration to STA3. Through multiple user information fields, the AP can allocate a duration for non-TB PPDU transmission or P2P transmission to each STA.

[0208] At this time, multiple STAs (ie, STA1, STA2, STA3) may simultaneously send a CTS frame to the AP in response to the MU-RTS TXS trigger frame.

[0209] In the case of STA1, since its own user information field is located in front, STA1 can perform P2P transmission within the allocated T_1 duration after receiving the MU-RTS TXS trigger frame, as described above Fig. 9 The process is shown in the figure.

[0210] STA2 to which T_2 duration has been allocated can recognize / identify that T_2 duration is the duration allocated thereto, starting from T_1 duration corresponding to the allocated duration information of STA1.

[0211] STA3 to which T_3 duration has been allocated can recognize / identify that T_3 duration is the duration allocated to it after the sum of T_1 duration and T_2 duration (T_1+T_2) based on T_1 duration corresponding to the allocated duration information of STA1 and T_2 duration corresponding to the allocated duration information of STA2.

[0212] Fig.12 The method described in has the advantage of low design complexity as far as multiple users (MU) are concerned.

[0213] Regarding this method, when each STA decodes the User Information List field, it is necessary to decode the Allocation Duration subfield of the User Information field except for its AID until it confirms the User Information field in which its AID is recognized.

[0214] Additionally or alternatively, with respect to this method, any STA may complete all transmissions before the time allocated to it expires, thereby performing a TXOP return to the AP. In this case, a channel corresponding to a portion of the duration allocated to the STA (i.e., the remaining duration after all transmissions are completed) may not be operated by any STA.

[0215] Additionally or alternatively, with respect to this method, some STAs may not respond (e.g., send a CTS frame to the AP) based on their channel status. For example, if Fig.12 If STA2 in the STA_1 does not respond to the CTS frame due to a busy (BUSY) channel, the T_2 duration may correspond to an inoperable duration. That is, there may be a situation where the channels corresponding to the T_1 duration and the T_3 duration are not operated by any STA.

[0216] Considering these points, in order to improve the utilization of duration / channel, a method can be additionally applied in which the AP notifies other STAs allocated with duration about information about duration / channel not operated by other STAs. In this regard, the AP can send a trigger frame to the corresponding STA.

[0217] First, a method in which an AP transmits a trigger frame to other STAs when a specific STA performs a TXOP return is described.

[0218] Fig.13 is a diagram for explaining an example of a TXOP sharing triggering procedure according to another example of the present disclosure.

[0219] Reference Fig.13 , the AP may send a MU-RTS TXS trigger frame with the TXOP sharing mode set to 2 to STA1 and STA2 corresponding to the P2P TX STA. Here, the MU-RTS TXS trigger frame may include a common information field and a user information list field, and the user list information field may include multiple user information fields for multiple STAs.

[0220] Specifically, the user information list field may include a first user information field (user information field #1) for allocating a T_1 duration to STA1 and a second user information field (user information field #2) for allocating a T_2 duration to STA2. Through multiple user information fields, the AP can allocate a duration for non-TB PPDU transmission or P2P transmission to each STA.

[0221] In this regard, STA1 and STA2 may simultaneously send a CTS frame to the AP in response to the MU-RTS TXS trigger frame.

[0222] STA1 may perform P2P operations during the T_1 duration allocated thereto.

[0223] If STA1 has no more frames to send within the duration of T_1, STA1 may perform a TXOP return to the AP to terminate the time allocated to it. For example, the TXOP return may be indicated by setting the RDG / More PPDU subfield of the HT Control in the MAC header to a value of 0. In this regard, QoS data / null frames may also be used.

[0224] At this time, STA2 needs to wait until the start of T_2 duration because it has not yet reached the start of T_2 duration and cannot recognize the TXOP return of STA1.

[0225] Taking this into consideration, in order to prevent channel waste during the duration before the start of the T_2 duration, the AP may send a frame to STA2 that triggers STA2 to perform P2P transmission using the duration.

[0226] Control frames or QoS data / null frames can be used as trigger frames to trigger corresponding operations.

[0227] For example, as an example of a control frame, the MU-RTS TXS trigger frame may be (re)used. This method may be the same as the method of allocating time for a single user (SU). At this time, the information for the duration for STA2 (ie, T_2 duration) may be changed to another time.

[0228] Since the trigger frame in the example corresponds to the MU-RTS TXS trigger frame occurring in the middle of the TXOP, and the pre-allocated time is changed based on this, it can be Fig.13 For example, for this operation, a reserved value (ie, 3) of the existing TXOP shared mode field may be used, or a reserved bit of the common information field included in the MU-RTS TXS trigger frame may be used.

[0229] Additionally or alternatively, due to Fig.13The trigger frame related to the operation in the QoS data / empty frame can be sent to STA2 separately, so the allocation time information for STA2 can be sent in the A-Control field of the MAC header by using the QoS data / empty frame. That is, a new type of A-Control field can be defined. In this case, the corresponding type of A-Control field includes the allocation duration subfield as described above, and may also include the RU allocation subfield and / or the PS160 subfield, etc.

[0230] Additionally or alternatively, with respect to Fig.13 For the operations in, the case where the RU location information (e.g., RU allocation subfield) or the time allocation information (e.g., allocation duration subfield) does not change can be considered. In this case, in order to reduce overhead, the AP can send an RTS frame corresponding to the QoS data / empty frame and a control frame to STA2 without information such as the above-mentioned A-Control field. At this time, the STA receiving the frame can recognize this and start transmission immediately because it has been allocated RU and / or duration through the previous MU-RTS TXS trigger frame.

[0231] Next, a method in which the AP transmits a trigger frame to another STA when a specific STA does not respond to a CTS frame is described.

[0232] Fig.14 is a diagram for explaining an example of a TXOP sharing triggering procedure according to another example of the present disclosure.

[0233] Reference Fig.14 , the AP may send a MU-RTS TXS trigger frame whose TXOP sharing mode is set to 2 to a plurality of STAs (i.e., STA1, STA2, and STA3) corresponding to the P2P TX STA. Here, the MU-RTS TXS trigger frame may include a common information field and a user information list field, and the user list information field may include a plurality of user information fields for a plurality of STAs.

[0234] Specifically, the user information list field may include a first user information field (user information field #1) for allocating a T_1 duration to STA1, a second user information field (user information field #2) for allocating a T_2 duration to STA2, and a third user information field (user information field #3) for allocating a T_3 duration to STA3. Through multiple user information fields, the AP can allocate a duration for non-TB PPDU transmission or P2P transmission to each STA.

[0235] In this regard, STA1 and STA3 simultaneously send CTS frames to the AP in response to the MU-RTS TXS trigger frame, and STA2 may not send a CTS frame to the AP. In this case, since there is no CTS frame response from STA2, the channel may not be operated during the T_2 duration allocated to STA2.

[0236] Therefore, in order to prevent the channel from being wasted during the duration of T_2, the AP may send a frame to STA3, which triggers STA3 to perform P2P transmission using the duration.

[0237] Control frames or QoS data / null frames can be used as trigger frames to trigger corresponding operations.

[0238] For example, as an example of a control frame, the MU-RTS TXS trigger frame may be (re)used. This method may be the same as the method of allocating time to a single user (SU). At this time, the information for the duration for STA3 (ie, T_3 duration) may be changed to another time.

[0239] Since the trigger frame in the example corresponds to the MU-RTS TXS trigger frame occurring in the middle of the TXOP, and the pre-allocated time is changed based on this, it can be Fig.14 For example, for this operation, a reserved value (ie, 3) of the existing TXOP shared mode field may be used, or a reserved bit of the common information field included in the MU-RTS TXS trigger frame may be used.

[0240] Additionally or alternatively, due to Fig.14 The trigger frame related to the operation in the QoS data / empty frame can be sent to STA3 separately, so the allocation time information for STA3 can be sent in the A-Control field of the MAC header by using the QoS data / empty frame. That is, a new type of A-Control field can be defined. In this case, the corresponding type of A-Control field includes the allocation duration subfield as described above, and may also include the RU allocation subfield and / or the PS160 subfield, etc.

[0241] Additionally or alternatively, with respect to Fig.14For the operations in, the case where the RU location information (e.g., RU allocation subfield) or the time allocation information (e.g., allocation duration subfield) does not change can be considered. In this case, in order to reduce overhead, the AP can send an RTS frame corresponding to the QoS data / empty frame and a control frame to STA3 without information such as the above-mentioned A-Control field. At this time, the STA receiving the frame can recognize this and start transmission immediately because it has been allocated RU and / or duration through the previous MU-RTS TXS trigger frame.

[0242] In addition, in order to prevent collision, a method of transmitting a trigger frame to another STA after a time allocated to one STA is described.

[0243] Fig.15 is a diagram for explaining a TXOP sharing triggering process according to another example of the present disclosure.

[0244] Reference Fig.15 , the AP may send a MU-RTS TXS trigger frame with the TXOP sharing mode set to 2 to STA1 and STA2 corresponding to the P2P TX STA. Here, the MU-RTS TXS trigger frame may include a common information field and a user information list field, and the user list information field may include multiple user information fields for multiple STAs.

[0245] Specifically, the user information list field may include a first user information field (user information field #1) for allocating a T_1 duration to STA1 and a second user information field (user information field #2) for allocating a T_2 duration to STA2. Through multiple user information fields, the AP can allocate a duration for non-TB PPDU transmission or P2P transmission to each STA.

[0246] In this regard, STA1 and STA2 may simultaneously send a CTS frame to the AP in response to the MU-RTS TXS trigger frame.

[0247] STA1 may perform P2P operations during the T_1 duration allocated thereto.

[0248] After STA1 completes the P2P operation, the AP may perform CCA during the PIFS period from the end of the time allocated to STA1 to avoid collision. If the channel is in the IDLE state according to the CCA, the AP may send a trigger frame to STA2.

[0249] STA2 that has received the trigger frame sends a response frame to the AP, and may perform a P2P operation (or send a non-TB PPDU to the AP) within a T_2 duration based on the response time.

[0250] Here, the trigger frame can be a control frame or a QoS data / null frame, similar to the above Fig.13 and 14 Those in .

[0251] For example, as an example of a control frame, the MU-RTS TXS trigger frame may be (re)used. This method may be the same as the method of allocating time for a single user (SU). At this time, the information for the duration for STA2 (ie, T_2 duration) may be changed to another time.

[0252] Since the trigger frame in this example corresponds to the MU-RTS TXS trigger frame that occurs in the middle of the TXOP, and the pre-allocated time is changed based on this, it can be Fig.15 For example, for this operation, a reserved value (ie, 3) of the existing TXOP shared mode field may be used, or a reserved bit of the common information field included in the MU-RTS TXS trigger frame may be used.

[0253] Additionally or alternatively, due to Fig.15 The trigger frame related to the operation in the QoS data / empty frame can be sent to STA2 separately, so the allocation time information for STA2 can be sent in the A-Control field of the MAC header by using the QoS data / empty frame. That is, a new type of A-Control field can be defined. In this case, the corresponding type of A-Control field includes the allocation duration subfield as described above, and may also include the RU allocation subfield and / or the PS160 subfield, etc.

[0254] Additionally or alternatively, with respect to Fig.15 For the operations in , the case where the RU location information (e.g., RU allocation subfield) or the time allocation information (e.g., allocation duration subfield) does not change can be considered. In this case, in order to reduce overhead, the AP can send an RTS frame corresponding to the QoS data / empty frame and a control frame to STA2 without information such as the above-mentioned A-Control field. At this time, the STA receiving the frame can recognize this and start transmission immediately because it has been allocated RU and / or duration through the previous MU-RTS TXS trigger frame.

[0255] The P2P transmission method (or non-TBPPDU transmission to the AP) for multiple users (eg, multiple STAs) proposed in this embodiment may be set to a specific mode.

[0256] That is, the STA receiving the MU-RTS TXS trigger frame can find / confirm the indication of the corresponding mode, thereby recognizing that the corresponding MU-RTS TX trigger frame is allocated to multiple users. In other words, the STA receiving the corresponding MU-RTS TXS trigger frame can recognize the existence of the multiple user information field and recognize that an operation may occur within the TXOP of the AP (for example, Fig.13 / Fig.14 transmission of the trigger frame in ).

[0257] Signaling of this mode may be performed as follows.

[0258] For example, a method of changing the meaning of the value 1 and the value 2 of the TXOP sharing mode subfield of the MU-RTS frame may be considered. That is, in the meaning of the value 1 and the value 2 of the TXOP sharing mode subfield of the above-mentioned MU-RTS frame, mode signaling may be performed by extending / changing the operation for one STA to the operation for one or more STAs.

[0259] For another example, a mode for P2P transmission to multiple STAs or non-TB PPDU transmission to an AP may be defined as a new TXOP sharing mode. That is, the value 3 (i.e., the previously reserved value) of the TXOP sharing mode subfield of the above-mentioned MU-RTS frame may be used to signal the mode.

[0260] As another example, the mode for P2P transmission to multiple STAs or non-TB PPDU transmission to the AP may be signaled through the common information field of the MU-RTS TXS trigger frame. For this purpose, a reserved bit (e.g., value 1) of the common information field may be used.

[0261] Implementation Method 2

[0262] The embodiment relates to a method for sequentially performing operations of transmitting a MU-RTS TXS frame to each STA and receiving a CST frame from the corresponding STA in order to support P2P transmission of a plurality of STAs.

[0263] Specifically, unlike the method of performing triggering for multiple STAs at one time in Embodiment 1, the AP can sequentially allocate a duration to each STA using the MU-RTS TXS trigger frame within one TXOP.

[0264] According to this method, when multiple STAs perform CTS responses at the same time, there may not be a situation where the AP cannot completely determine which STA performs the response. In addition, there may not be a situation where some durations / channels allocated to a certain STA are not operated.

[0265] Fig.16 is a diagram for explaining a TXOP sharing triggering process according to another example of the present disclosure.

[0266] Reference Fig.16 , the MU-RTS TXS trigger frame can be used to continuously allocate a duration for P2P operation to each STA.

[0267] That is, when P2P transmission is terminated during the allocated duration of each STA within one TXOP, the AP may allocate a duration for P2P transmission by sending a MU-RTS TXS trigger frame to the next STA.

[0268] For example, the AP may send a MU-RTS TXS trigger frame with the TXOP sharing mode set to 2 to STA1 corresponding to the P2P TX STA. Here, the MU-RTS TXS trigger frame may include a common information field and a user information list field. The user information list field may include a first user information field (user information field #1) for allocating a T_1 duration to STA1. STA1 may send a CTS frame to the AP as a response to the MU-RTS TXS trigger frame and perform a P2P operation during the T_1 duration.

[0269] When the P2P operation of STA1 is terminated, the AP may send a MU-RTS TXS trigger frame with the TXOP sharing mode set to 2 to STA2 corresponding to another P2P TX STA. Here, the MU-RTS TXS trigger frame may include a common information field and a user information list field. The user information list field may include a second user information field (user information field #2) for allocating a T_2 duration to STA2. STA2 may send a CTS frame to the AP as a response to the MU-RTS TXS trigger frame and perform a P2P operation during the T_2 duration.

[0270] If, such as Fig.13 As shown, if STA1 performs TXOP return or does not perform transmit / receive (TX / RS) operation during the operation duration, the AP may send a MU-RST TXS trigger frame for duration allocation to STA2.

[0271] Regarding the method described in the present disclosure, the method proposed in Embodiment 1 has the effect of reducing the overhead for trigger frame signaling by being able to allocate durations to multiple STAs at once. In addition, even if some time intervals / channels are not operable, the above additional proposed methods (e.g., Fig.13 and Fig.14 QoS data / empty frame / RTS frame transmission) triggers the next STA to resolve.

[0272] If this situation occurs frequently, a method of allocating a duration for P2P transmission by individually transmitting a MU-RTS TXS trigger frame to each STA using the method proposed in Embodiment 2 may be applied.

[0273] In existing wireless LAN systems, the trigger frame for TXOP sharing (i.e., the MU-RTS TXS trigger frame) includes only one user information field. Therefore, the duration allocation for P2P transmission or non-TB PPDU transmission may only be for one STA. In contrast, the method proposed in the present disclosure may include one or more user information fields, i.e., multiple user message fields, in the MU-RTS TXS trigger frame. In this way, it has a new feature, namely, it is possible to use one MU-RTS TXS trigger frame to allocate duration for P2P transmission or non-TB PPDU transmission for multiple STAs. Therefore, multiple P2P transmissions can be supported within one TXOP, and since time allocation can be performed for multiple STAs at a time, signaling overhead is reduced and efficiency is improved, which can achieve new effects.

[0274] The above-mentioned embodiments are to combine the elements and features of the present disclosure in a predetermined form. Unless otherwise explicitly mentioned, each element or feature should be considered as optional. Each element or feature can be implemented in a form that is not combined with other elements or features. In addition, the embodiments of the present disclosure may include combined partial elements and / or features. The order of the operations described in the embodiments of the present disclosure may be changed. Some elements or features of an embodiment may be included in other embodiments, or may be replaced by corresponding elements or features of other embodiments. Obviously, the embodiments may include claims that do not have a clear reference relationship in the combined claims, or may be included as new claims by modification after application.

[0275] It is clear to those skilled in the relevant art that the present disclosure can be implemented in other specific forms within the scope of the essential features of the present disclosure. Therefore, the above detailed description should not be interpreted restrictively in every aspect, but should be considered as illustrative. The scope of the present disclosure should be determined by the reasonable interpretation of the attached claims, and all changes within the equivalent scope of the present disclosure are included in the scope of the present disclosure.

[0276] The scope of the present disclosure includes software or machine executable commands (e.g., operating systems, applications, firmware, programs, etc.) that perform operations in a device or computer according to the methods of various embodiments, and non-transitory computer-readable media that enable software or commands, etc. to be stored and executable in a device or computer. Commands that can be used to program a processing system that performs the features described in the present disclosure can be stored in a storage medium or a computer-readable storage medium, and the features described in the present disclosure can be implemented by using a computer program product including such a storage medium. The storage medium may include a high-speed random access memory, such as DRAM, SRAM, DDR RAM, or other random access solid-state storage devices, but is not limited thereto, and it may include a non-volatile memory, such as one or more magnetic disk storage devices, optical disk storage devices, flash memory devices, or other non-volatile solid-state storage devices. The memory optionally includes one or more storage devices located away from the processor. The memory, or alternatively, the non-volatile memory device in the memory includes a non-transitory computer-readable storage medium. The features described in this disclosure may be stored in any machine-readable medium to control the hardware of a processing system, and may be integrated into software and / or firmware that allows the processing system to interact with other mechanisms using the results from the embodiments of this disclosure. Such software or firmware may include, but is not limited to, application code, device drivers, operating systems, and execution environments / containers.

[0277] Industrial Applicability

[0278] The method proposed in the present disclosure is mainly described based on an example applied to a system based on IEEE 802.11 (5G system), but can be applied to various WLAN or wireless communication systems other than the system based on IEEE 802.11.

Claims

1. A method performed by a station STA in a wireless LAN system, the method comprising the following steps: receiving a trigger frame related to sharing of a transmission opportunity TXOP from an access point AP; as well as sending a response frame to the trigger frame to the AP, The trigger frame includes a common information field and multiple user information fields for multiple STAs including the STA, and Wherein, the timing of the duration allocated to the STA within the TXOP is identified based on the order of the user information field for the STA among the plurality of user information fields.

2. The method according to claim 1, in, Based on the presence of one or more user information fields for one or more other STAs included in the multiple STAs before the user information field for the STA, the timing of the duration allocated to the STA is positioned after the sum of the one or more durations allocated to the one or more other STAs.

3. The method according to claim 2, in, The sum of the one or more durations is calculated by the STA by decoding the one or more user information fields.

4. The method according to claim 1, further comprising the steps of: performing transmission of a frame addressed to another STA during a duration allocated to said STA, The TXOP sharing mode subfield included in the common information field is set to a value indicating a TXOP sharing mode for allocating time to transmit a frame addressed to the other STA from the STA.

5. The method according to claim 1, further comprising the steps of: Based on that a user information field for another STA included in the plurality of STAs is located before the user information field for the STA and there is a TXOP return by the another STA, a frame triggering duration allocation within the TXOP is received from the AP.

6. The method according to claim 5, in, The frame corresponds to at least one of a control frame, a Quality of Service (QoS) data frame, or a QoS null frame.

7. The method according to claim 1, further comprising the steps of: A frame for triggering duration allocation within the TXOP is received from the AP based on a user information field for another STA included in the plurality of STAs being located before the user information field for the STA and there being no response frame transmitted by the another STA to the trigger frame.

8. The method according to claim 7, in, The frame corresponds to at least one of a control frame, a Quality of Service (QoS) data frame, or a QoS null frame.

9. The method according to claim 1, further comprising the steps of: Based on the fact that a user information field for another STA included in the multiple STAs is located before the user information field for the STA and that a channel is in an idle state at an end timing of the duration allocated to the other STA, a frame that triggers duration allocation within the TXOP after PIFS based on the end timing is received from the AP.

10. The method according to claim 1, in, The TXOP sharing mode subfield included in the common information field is set to a value indicating a TXOP sharing mode for allocating time to the plurality of STAs based on the plurality of user information fields.

11. The method according to claim 1, in, The common information field includes specific 1-bit information for indicating a TXOP sharing mode for allocating time to the plurality of STAs based on the plurality of user information fields.

12. The method according to claim 1, in, The trigger frame corresponds to a multi-user request to send a MU-RTS TXOP shared TXS trigger frame, and The response frame corresponds to a Clear to Send (CTS) frame for the MU-RTS TXS trigger frame.

13. The method according to claim 12, in, The STA is a STA associated with the AP or a STA within the coverage of a BSS to which the AP belongs.

14. A device for a station STA in a wireless local area network (WLAN) system, the device comprising: at least one transceiver; as well as at least one processor connected to the at least one transceiver, Wherein, the at least one processor is configured to: receiving a trigger frame related to sharing of a transmission opportunity TXOP from an access point AP; and sending a response frame to the trigger frame to the AP, The trigger frame includes a common information field and multiple user information fields for multiple STAs including the STA, and Wherein, the timing of the duration allocated to the STA within the TXOP is identified based on the order of the user information field for the STA among the plurality of user information fields.

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

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

17. A method performed by an access point (AP) in a wireless LAN system, the method comprising the following steps: Sending a trigger frame related to sharing of a transmission opportunity TXOP to a plurality of stations STA; as well as receiving a response frame to the trigger frame from one or more STAs among the plurality of STAs, The trigger frame includes a common information field and multiple user information fields for the multiple STAs, and Wherein, the timing of the duration allocated to the STA within the TXOP is determined based on the order of the user information field for each STA among the plurality of user information fields.

18. A device for an access point AP in a wireless local area network (WLAN) system, the device comprising: at least one transceiver; as well as at least one processor connected to the at least one transceiver, Wherein, the at least one processor is configured to: Sending a trigger frame related to sharing of a transmission opportunity TXOP to a plurality of stations STA; and receiving a response frame to the trigger frame from one or more STAs among the plurality of STAs, The trigger frame includes a common information field and multiple user information fields for the multiple STAs, and Wherein, the timing of the duration allocated to the STA within the TXOP is determined based on the order of the user information field for each STA among the plurality of user information fields.

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