Method and apparatus for transmitting and receiving aggregated physical layer protocol data unit in wireless LAN system

Abstract

Disclosed are a method and an apparatus for operation in a wireless LAN system. According to one embodiment of the present disclosure, a method performed by a first STA in a wireless LAN system comprises the steps of: receiving a trigger frame for aggregating a physical layer protocol data unit (A-PPDU) transmission from a second STA; and receiving the A-PPDU from the second STA based on a trigger frame, where the trigger frame may include first information related to at least one frequency resource unit for latency sensitive (LS) data transmission and second information related to timing for LS data transmission.

Description

Technical Field

[0001] The present disclosure relates to communication operations in a wireless local area network (WLAN) system, and more particularly, to methods and apparatuses for transmitting and receiving aggregated physical layer protocol data units (PPDUs) in a next-generation wireless LAN system. Background Art

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

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

[0004] Technical Problem

[0005] A technical problem of the present disclosure is to provide methods and apparatuses for performing A (aggregated)-PPDU transmission and reception in a wireless LAN system.

[0006] A technical problem of the present disclosure is to provide methods and apparatuses for indicating a channel and / or timing for transmission of latency-sensitive (LS) data based on a trigger frame.

[0007] The technical objectives to be achieved by the present disclosure are not limited to the above technical objectives, and other technical objectives not described herein will be clearly understood by those skilled in the art from the following description.

[0008] Technical Solution

[0009] According to an embodiment of the present disclosure, a method performed by a first station (STA) in a wireless LAN system may include: receiving, from a second STA, a trigger frame for transmitting an aggregated physical layer protocol data unit (A-PPDU); and receiving, from the second STA, the A-PPDU based on the trigger frame, and the trigger frame may include first information related to at least one frequency resource unit for latency-sensitive (LS) data transmission and second information related to timing for LS data transmission.

[0010] According to another embodiment of the present disclosure, a method performed by a second station (STA) in a wireless LAN system may include: sending a trigger frame for sending an aggregated physical layer protocol data unit (A-PPDU) to a first STA; and sending the A-PPDU to the first STA based on the trigger frame, and the trigger frame may include first information related to at least one frequency resource unit for latency-sensitive (LS) data transmission and second information related to timing for LS data transmission.

[0011] Technical Effects

[0012] According to various embodiments of the present disclosure, methods and apparatuses for efficiently performing A-PPDU transmission and reception in a wireless LAN system may be provided.

[0013] According to various embodiments of the present disclosure, methods and devices for indicating a channel and / or timing for delayed traffic transmission based on a trigger frame may be provided.

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

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

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

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

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

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

[0020] Figure 5 Is a diagram for explaining a CSMA / CA-based frame transmission operation to which the present disclosure may be applied.

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

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

[0023] Figure 8 It illustrates an exemplary format of a trigger frame to which the present disclosure can be applied.

[0024] Figure 9 It is a diagram for explaining the structure of an A-PPDU to which the present disclosure can be applied.

[0025] Figure 10 and Figure 11 It is a diagram for explaining a method of transmitting an A-PPDU and an intercepted PPDU according to an embodiment of the present disclosure.

[0026] Figure 12 It is a diagram illustrating an example of a sub-channel selective transmission (SST) operation element format to which the present disclosure can be applied.

[0027] Figure 13 It is a flowchart for explaining a method for a first STA to transmit and receive a PPDU according to an embodiment of the present disclosure.

[0028] Figure 14 It is a flowchart for explaining a method for a second STA to transmit and receive a PPDU according to an embodiment of the present disclosure.

[0029] Figure 15 It is a diagram for explaining a trigger frame and an A-PPDU transmission process according to an embodiment of the present disclosure. Detailed Embodiments

[0030] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. The detailed description to be disclosed through the drawings is to describe exemplary embodiments of the present disclosure, rather than indicating the only embodiments in which the present disclosure can be implemented. The following detailed description includes specific details to provide a complete understanding of the present disclosure. However, those skilled in the relevant art know that the present disclosure can be implemented without these specific details.

[0031] In some cases, known structures and devices may be omitted, or may be shown in the form of a block diagram based on the core functions of each structure and device in order to prevent the concepts of the present disclosure from being ambiguous.

[0032] 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 as well as a direct connection relationship in which another element exists therebetween. In addition, in the present disclosure, the terms "include" or "have" specify the existence of the recited features, steps, operations, components, and / or elements, but do not exclude the existence or addition of one or more other features, stages, operations, components, elements, and / or groups thereof.

[0033] In the present disclosure, terms such as "first", "second", etc. are only used to distinguish one element from another and do not limit the element, unless otherwise specified, and do not limit the order or importance between elements, etc. Therefore, within the scope of the present disclosure, the first element in an embodiment can be referred to as the second element in another embodiment, and similarly, the second element in an embodiment can be referred to as the first element in another embodiment.

[0034] The terms used in the present disclosure are for the purpose of describing specific embodiments and do not limit the claims. As used in the description of the embodiments and the appended claims, the singular forms are intended to include the plural forms unless the context clearly indicates otherwise. The term "and / or" used in the present disclosure can refer to one of the related listed items or means that it refers to and includes any and all possible combinations of two or more of them. In addition, unless otherwise specified, the " / " between words in the present disclosure has the same meaning as "and / or".

[0035] Examples of the present disclosure can be applied to various wireless communication systems. For example, examples of the present disclosure can be applied to a wireless LAN system. For example, examples of the present disclosure can be applied to a wireless LAN based on the IEEE 802.11a / g / n / ac / ax standards. In addition, examples of the present disclosure can be applied to a wireless LAN based on the newly proposed IEEE 802.11be (or EHT) standard. Examples of the present disclosure can be applied to a wireless LAN based on the IEEE 802.11be version 2 standard corresponding to additional enhancement technologies of the IEEE 802.11be version 1 standard. Additionally, examples of the present disclosure can be applied to a wireless LAN based on the next-generation standard after IEEE 802.11be. Furthermore, examples of the present disclosure can be applied to a cellular wireless communication system. For example, it can be applied to a cellular wireless communication system based on the Long-Term Evolution (LTE) technology and the 5G New Radio (NR) technology based on the Third Generation Partnership Project (3GPP) standards.

[0036] Hereinafter, the technical features to which the examples of the present disclosure can be applied will be described.

[0037] Figure 1 A block diagram of a wireless communication device according to an embodiment of the present disclosure is illustrated.

[0038] Figure 1The first device 100 and the second device 200 illustrated in the example can be replaced with various terms such as a terminal, a wireless device, a wireless transmit / receive unit (WTRU), a user equipment (UE), a mobile station (MS), a user terminal (UT), a mobile subscriber station (MSS), a mobile subscriber unit (MSU), a subscriber station (SS), an advanced mobile station (AMS), a wireless terminal (WT), or simply a user. Additionally, the first device 100 and the second device 200 include an access point (AP), a base station (BS), a fixed station, a Node B, a base transceiver system (BTS), a network. It can be replaced with various terms such as an artificial intelligence (AI) system, a roadside unit (RSU), a repeater, a router, a relay, and a gateway.

[0039] Figure 1 The devices 100 and 200 illustrated in the example can be referred to as a station (STA). For example, Figure 1 The devices 100 and 200 illustrated in the example can be referred to by various terms such as a transmitting device, a receiving device, a transmitting STA, and a receiving STA. For example, STAs 110 and 200 can perform an access point (AP) role or a non-AP role. That is, in the present disclosure, STAs 110 and 200 can perform AP and / or non-AP functions. When STAs 110 and 200 perform the AP function, they can be simply referred to as APs, and when STAs 110 and 200 perform the non-AP function, they can be simply referred to as STAs. Additionally, in the present disclosure, an AP can also be indicated as an AP STA.

[0040] Referring to Figure 1 , the first device 100 and the second device 200 can transmit and receive radio signals through various wireless LAN technologies (e.g., the IEEE 802.11 series). The first device 100 and the second device 200 can include interfaces for a media access control (MAC) layer and a physical layer (PHY) compliant with the IEEE 802.11 standard.

[0041] Additionally, in addition to wireless LAN technologies, the first device 100 and the second device 200 can additionally support various communication standard (e.g., 3GPP LTE series, 5G NR series standards, etc.) technologies. Additionally, the devices of the present disclosure can be implemented in various devices such as a mobile phone, a vehicle, a personal computer, an augmented reality (AR) device, and a virtual reality (VR) device. Additionally, the STAs in this specification can support various communication services such as a voice call, a video call, data communication, autonomous driving, machine type communication (MTC), machine-to-machine (M2M), device-to-device (D2D), and IoT (Internet of Things).

[0042] The first device 100 may include one or more processors 102 and one or more memories 104, and may additionally include one or more transceivers 106 and / or one or more antennas 108. The processor 102 may control the memory 104 and / or the transceiver 106, and may be configured to implement the descriptions, functions, processes, suggestions, methods, and / or operation flowcharts included in the present disclosure. For example, after generating first information / signals by processing information in the memory 104, the processor 102 may transmit a wireless signal including the first information / signals via the transceiver 106. Additionally, the processor 102 may receive a wireless signal including second information / signals via the transceiver 106, and then store the information obtained by signal processing of the second information / signals in the memory 104. The memory 104 may be connected to the processor 102 and may store various information related to the operation of the processor 102. For example, the memory 104 may store software code including instructions for performing all or part of the processing controlled by the processor 102 or for performing the descriptions, functions, processes, suggestions, methods, and / or operation flowcharts included in the present disclosure. Here, the processor 102 and the memory 104 may be part of a communication modem / circuit / chip designed to implement wireless LAN technology (e.g., the IEEE 802.11 series). The transceiver 106 may be connected to the processor 102 and may transmit and / or receive wireless signals via one or more antennas 108. The transceiver 106 may include a transmitter and / or a receiver. The transceiver 106 may be used with an RF (radio frequency) unit. In the present disclosure, a wireless device may mean a communication modem / circuit / chip.

[0043] The second device 200 may include one or more processors 202 and one or more memories 204, and may additionally include one or more transceivers 206 and / or one or more antennas 208. The processor 202 may control the memory 204 and / or the transceiver 206, and may be configured to implement the descriptions, functions, processes, suggestions, methods, and / or operation flowcharts included in the present disclosure. For example, the processor 202 may generate third information / signals by processing the information in the memory 204, and then transmit wireless signals including the third information / signals through the transceiver 206. Additionally, the processor 202 may receive wireless signals including fourth information / signals through the transceiver 206, and then store the information obtained by signal processing of the fourth information / signals in the memory 204. The memory 204 may be connected to the processor 202 and may store various information related to the operation of the processor 202. For example, the memory 204 may store software codes including instructions for performing all or part of the processing controlled by the processor 202 or for performing the descriptions, functions, processes, suggestions, methods, and / or operation flowcharts included in the present disclosure. Here, the processor 202 and the memory 204 may be part of a communication modem / circuit / chip designed to implement wireless LAN technology (e.g., the IEEE 802.11 series). The transceiver 206 may be connected to the processor 202 and may transmit and / or receive wireless signals through one or more antennas 208. The transceiver 206 may include a transmitter and / or a receiver. The transceiver 206 may be used with an RF unit. In the present disclosure, a device may mean a communication modem / circuit / chip.

[0044] Hereinafter, the hardware components of apparatuses 100 and 200 will be described in more detail. Without being limited thereto, one or more protocol layers may be implemented by one or more processors 102 and 202. For example, one or more processors 102 and 202 may implement one or more layers (e.g., functional layers such as PHY and MAC). One or more processors 102 and 202 may generate one or more PDUs (Protocol Data Units) and / or one or more SDUs (Service Data Units) according to the descriptions, functions, procedures, suggestions, methods, and / or operation flowcharts disclosed in the present disclosure. One or more processors 102 and 202 may generate messages, control information, data, or information according to the descriptions, functions, procedures, suggestions, methods, and / or operation flowcharts disclosed in the present disclosure. One or more processors 102 and 202 may generate signals (e.g., baseband signals) including PDUs, SDUs, messages, control information, data, or information according to the functions, procedures, suggestions, and / or methods disclosed in the present disclosure to provide them to one or more transceivers 106 and 206. One or more processors 102 and 202 may receive signals (e.g., baseband signals) from one or more transceivers 106 and 206 according to the descriptions, functions, procedures, suggestions, methods, and / or operation flowcharts included in the present disclosure, and obtain PDUs, SDUs, messages, control information, data, or information.

[0045] One or more processors 102 and 202 may be referred to as a controller, a microcontroller, a microprocessor, or a microcomputer. One or more processors 102 and 202 may be implemented by hardware, firmware, software, or a combination thereof. For example, one or more ASICs (Application Specific Integrated Circuits), one or more DSPs (Digital Signal Processors), one or more DSPDs (Digital Signal Processor Devices), one or more PLDs (Programmable Logic Devices), or one or more FPGAs (Field Programmable Gate Arrays) may be included in one or more processors 102 and 202. The descriptions, functions, procedures, suggestions, methods, and / or operation flowcharts included in the present disclosure may be implemented by using firmware or software, and the firmware or software may be implemented to include modules, procedures, functions, etc. The firmware or software configured to execute the descriptions, functions, procedures, suggestions, methods, and / or operation flowcharts included in the present disclosure may be included in one or more processors 102 and 202, or may be stored in one or more memories 104 and 204 and driven by one or more processors 102 and 202. The descriptions, functions, procedures, suggestions, methods, and / or operation flowcharts included in the present disclosure may be implemented by using firmware or software in the form of code, instructions, and / or instruction sets.

[0046] One or more memories 104, 204 may be connected to one or more processors 102, 202 and may store data, signals, messages, information, programs, code, instructions, and / or commands in various forms. One or more memories 104, 204 may be configured with ROM, RAM, EPROM, flash memory, hard disk drives, registers, cache memories, computer-readable storage media, and / or combinations thereof. One or more memories 104, 204 may be located inside and / or outside one or more processors 102, 202. Additionally, one or more memories 104, 204 may be connected to one or more processors 102, 202 through various techniques such as wired or wireless connections.

[0047] One or more transceivers 106, 206 may send user data, control information, wireless signals / channels, etc. mentioned in the methods and / or operation flowcharts, etc. of the present disclosure to one or more other devices. One or more transceivers 106, 206 may receive user data, control information, wireless signals / channels, etc. mentioned in the descriptions, functions, processes, suggestions, methods, and / or operation flowcharts, etc. included in the present disclosure from one or more other devices. For example, one or more transceivers 106, 206 may be connected to one or more processors 102, 202 and may send and receive wireless signals. For example, one or more processors 102, 202 may control one or more transceivers 106, 206 to send user data, control information, or wireless signals to one or more other devices. Additionally, one or more processors 102, 202 may control one or more transceivers 106, 206 to receive user data, control information, or wireless signals from one or more other devices. Additionally, one or more transceivers 106, 206 may be connected to one or more antennas 108, 208, and one or more transceivers 106, 206 may be configured to send and receive user data, control information, wireless signals / channels, etc. mentioned in the descriptions, functions, processes, suggestions, methods, and / or operation flowcharts, etc. included in the present disclosure through one or more antennas 108, 208. In the present disclosure, one or more antennas may be multiple physical antennas or multiple logical antennas (e.g., antenna ports). One or more transceivers 106, 206 may convert the received wireless signals / channels, etc. from RF band signals into baseband signals to process the received user data, control information, wireless signals / channels, etc. by using one or more processors 102, 202. One or more transceivers 106, 206 may convert the user data, control information, wireless signals / channels, etc. processed by using one or more processors 102, 202 from baseband signals into RF band signals. Thus, one or more transceivers 106, 206 may include (analog) oscillators and / or filters.

[0048] For example, one of STAs 100 and 200 may perform the expected operations of an AP, and the other of STAs 100 and 200 may perform the expected operations of a non-AP STA. For example, Figure 1 the transceivers 106 and 206 may perform the sending and receiving operations of signals (e.g., packets or physical layer protocol data units (PPDUs) compliant with IEEE 802.11a / b / g / n / ac / ax / be / bn). Additionally, in the present disclosure, the operations of various STAs generating transmission / reception signals or pre-performing data processing or calculations for transmission / reception signals may be performed by Figure 1The processors 102 and 202 execute. For example, examples of operations that generate transmission / reception signals or perform data processing or calculations in advance for transmission / reception signals may include: 1) determining / acquiring / configuring / calculating / decoding / encoding bit information of fields (signals (SIG), short training fields (STF), long training fields (LTF), data, etc.) included in a PPDU; 2) determining / configuring / acquiring time resources or frequency resources (e.g., subcarrier resources) for fields (SIG, STF, LTF, data, etc.) included in a PPDU; 3) determining / configuring / acquiring a specific sequence (e.g., a pilot sequence, an STF / LTF sequence, an additional sequence applied to SIG) for fields (SIG, STF, LTF, data, etc.) included in a PPDU operation; 4) power control operations and / or power saving operations applied to a STA; 5) operations related to determining / acquiring / configuring / calculating / decoding / encoding, etc. of an ACK signal. Additionally, in the following examples, various information (e.g., information related to fields / sub-fields / control fields / parameters / power, etc.) used by various STAs to determine / acquire / configure / calculate / decode / encode transmission signals and reception signals may be stored in Figure 1 the memories 104 and 204.

[0049] Hereinafter, a downlink (DL) may refer to a link for communication from an AP STA to a non-AP STA, and DL PPDUs / packets / signals may be transmitted and received through the DL. In DL communication, the transmitter may be part of the AP STA, and the receiver may be part of the non-AP STA. An uplink (UL) may refer to a link for communication from a non-AP STA to an AP STA, and UL PPDUs / packets / signals may be transmitted and received through the UL. In UL communication, the transmitter may be part of the non-AP STA, and the receiver may be part of the AP STA.

[0050] Figure 2 is a diagram illustrating an exemplary structure of a wireless LAN system to which the present disclosure may be applied.

[0051] The structure of a wireless LAN system may be composed of multiple components. A wireless LAN that supports STA mobility transparent to the upper layer may be provided through the interaction of multiple components. A basic service set (BSS) corresponds to the basic building block of a wireless LAN. Figure 2 Exemplarily, it is shown that there are two BSSs (BSS1 and BSS2), and two STAs (STA1 and STA2 are included in BSS1, and STA3 and STA4 are included in BSS2) included as members of each BSS. Figure 2The ellipse representing the BSS can also be understood as representing the coverage area where STAs included in the corresponding BSS maintain communication. This area can be referred to as the Basic Service Area (BSA). When an STA moves outside the BSA, it cannot communicate directly with other STAs within the BSA.

[0052] If the DS shown in Figure 2 is not considered, the most basic type of BSS in a wireless LAN is the Independent BSS (IBSS). For example, an IBSS can have a minimum form that only contains two STAs. For example, assuming other components are omitted, BSS1 that only contains STA1 and STA2 or BSS2 that only contains STA3 and STA4 can respectively correspond to representative examples of an IBSS. This configuration is possible when STAs can communicate directly without an AP. Additionally, in this type of wireless LAN, it is not pre-configured but can be configured when a LAN is needed, and this can be referred to as an ad-hoc network. Since an IBSS does not include an AP, there is no centralized management entity. That is, in an IBSS, STAs are managed in a distributed manner. In an IBSS, all STAs can consist of mobile STAs and are not allowed to access the Distributed System (DS), thus forming a self-contained network.

[0053] The membership of STAs in a BSS can be dynamically changed by turning on or off STAs, entering or exiting the BSS area, etc. To become a member of a BSS, an STA can use synchronization processing to join the BSS. To access all services of the BSS infrastructure, an STA should be associated with the BSS. This association can be dynamically established and can include using the Distribution System Service (DSS).

[0054] The direct STA-to-STA distance in a wireless LAN may be limited by the PHY performance. In some cases, this distance limitation may be sufficient, but in some cases, communication between STAs at longer distances may be required. The Distributed System (DS) can be configured to support extended coverage.

[0055] DS means the structure for interconnecting BSSs. Specifically, as Figure 2As shown, the BSS can exist as an extended form of a network composed of multiple BSSs. The DS is a logical concept and can be specified by the characteristics of the distributed system medium (DSM). In this regard, the wireless medium (WM) and the DSM can be logically separated. Each logical medium is used for 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 structures) can be interpreted as multiple media being logically different. That is to say, 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.

[0056] The DS can support mobile devices by providing seamless integration of multiple BSSs and providing the logical services necessary for addressing the addresses to the destination. In addition, the DS can also include a component called a portal, which is used as a bridge for the connection between the wireless LAN and other networks (such as IEEE 802.X).

[0057] The AP enables access to the DS via the WM for the associated non-AP STA and refers to an entity that also has the STA function. The data movement between the BSS and the DS can be performed by the AP. For example, Figure 2 STA2 and STA3 shown in have the functions of the STA and provide the functions that allow the associated non-AP STAs (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 for communication on the WM is not necessarily the same as the address used by the AP for communication on the DSM. The BSS composed of an AP and one or more STAs can be called an infrastructure BSS.

[0058] 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.

[0059] In addition to the above DS structure, the extended service set (ESS) can also be configured to provide wide coverage.

[0060] An ESS means a network consisting of a DS and BSSs, with any size and complexity. An ESS can correspond to a set of BSSs connected to a DS. However, an ESS does not include the DS. The ESS network is characterized by an IBSS in the logical link control (LLC) layer. STAs included in an ESS can communicate with each other, and a mobile STA can move from one BSS to another (within the same ESS) transparently to the LLC. APs included in an ESS can have the same service set identifier (SSID). The SSID is distinguished from the BSSID which is the identifier of a BSS.

[0061] The wireless LAN system does not assume anything about the relative physical positions of BSSs, and all of the following forms are possible. BSSs can partially overlap, which is a form often used to provide continuous coverage. Additionally, BSSs can be not physically connected, and logically, there is no limit to the distance between BSSs. Additionally, BSSs can be physically located at the same position, which can be used to provide redundancy. Additionally, one (or more than one) IBSS or ESS network can physically exist in the same space as one (or more than one) ESS network. This can correspond to forms of an ESS network when an ad-hoc network operates at the location where an ESS network exists, when physically overlapping wireless networks are configured by different organizations, or when two or more different access and security policies are required at the same position.

[0062] Figure 3 is a diagram for explaining the link establishment process to which the present disclosure can be applied.

[0063] In order for an STA to establish a link with respect to a network and send / receive data, it first discovers the network, performs authentication, establishes an association, and an authentication process is required for security. The link establishment process can also be referred to as a session initiation process or a session establishment process. Additionally, the processes of discovery, authentication, association, and security establishment in the link establishment process can be collectively referred to as an association process.

[0064] In step S310, the STA can perform a network discovery operation. The network discovery operation can include a scanning operation of the STA. That is, in order for the STA to access the network, it needs to find the network it can participate in. The STA should identify compatible networks before participating in the wireless network, and the process of identifying the networks existing in a specific area is called scanning.

[0065] Scanning schemes include active scanning and passive scanning. Figure 3A network discovery operation including an active scanning process is exemplarily illustrated. In active scanning, the STA performing the scan sends a probe request frame to discover which APs exist around it while moving across channels and waits for a response thereto. The responder sends a probe response frame as a response to the probe request frame to the STA that has sent the probe request frame. Here, the responder can be the STA that last sent a beacon frame in the BSS of the channel being scanned. In a BSS, since the AP sends a beacon frame, the AP becomes the responder, and in an IBSS, the STAs in the IBSS rotate to send beacon frames, so the responder is not constant. For example, the STA that sends a probe request frame on channel 1 and receives a probe response frame on channel 1 can store the BSS-related information included in the received probe response frame, and can move to the next channel (e.g., channel 2), and perform the scan in the same way (i.e., send and receive probe requests / responses on channel 2).

[0066] Although not shown in Figure 3 it, the scan operation can be performed in a passive scanning manner. In passive scanning, the STA performing the scan waits for beacon frames while moving across channels. A beacon frame is one of the management frames defined in IEEE 802.11 and is periodically sent to notify the existence of a wireless network and to allow the STA performing the scan to find the wireless network and participate in the wireless network. In a BSS, the AP is used to periodically send beacon frames, and in an IBSS, the STAs within the IBSS rotate to send beacon frames. When the STA performing the scan receives a beacon frame, the STA stores the information of the BSS included in the beacon frame, and while moving to another channel, records the beacon frame information in each channel. The STA that receives a beacon frame can store the BSS-related information included in the received beacon frame, move to the next channel, and perform the scan in the next channel in the same way. Comparing active scanning with passive scanning, the advantage of active scanning is that it has less latency and less power consumption than passive scanning.

[0067] After the STA discovers the network, the authentication process can be performed in step S320. To clearly distinguish it from the security establishment operation in step S340 to be described later, this authentication process can be referred to as the first authentication process.

[0068] The authentication process includes the following processes: the STA sends an authentication request frame to the AP, and in response thereto, the AP sends an authentication response frame to the STA. The authentication frames for authentication request / response correspond to management frames.

[0069] The authentication frame includes an authentication algorithm number, an authentication transaction serial number, a status code, a challenge text, a Robust Security Network (RSN), a finite cyclic group, etc. This corresponds to some examples of information that can be included in the authentication request / response frame, and can be replaced with other information, or additional information can also be included.

[0070] The STA can send an authentication request frame to the AP. The AP can determine whether to allow the authentication of the corresponding STA based on the information included in the received authentication request frame. The AP can provide the result of the authentication process to the STA through an authentication response frame.

[0071] After the STA is successfully authenticated, the association process can be performed in step S330. The association process includes the following processes: the STA sends an association request frame to the AP, and in response, the AP sends an association response frame to the STA.

[0072] For example, the association request frame can include information related to various capabilities, a beacon listening interval, a Service Set Identifier (SSID), supported rates, supported channels, RSN, a mobility domain, supported operation classes, a Traffic Indication Map Broadcast Request (TIM broadcast request), interoperable service capabilities, etc. For example, the association response frame can include information related to various capabilities, a status code, an Association ID (AID), supported rates, an Enhanced Distributed Channel Access (EDCA) parameter set, a Received Channel Power Indicator (RCPI), a Received Signal-to-Noise Ratio Indicator (RSNI), a mobility domain, a timeout interval (e.g., an association recovery time), overlapping BSS scan parameters, a TIM broadcast response, Quality of Service (QoS) mapping, etc. This corresponds to some examples of information that can be included in the association request / response frame, and can be replaced with other information, or additional information can also be included.

[0073] After the STA is successfully associated with the network, the security establishment process can be performed in step S340. The security establishment process in step S340 can be referred to as an authentication process through Robust Security Network Association (RSNA) request / response. The authentication process in step S320 is referred to as the first authentication process, and the security establishment process in step S340 can also be simply referred to as an authentication process.

[0074] The security establishment process in step S340 can include, for example, a process of establishing a private key using the Extensible Authentication Protocol over LAN (EAPOL) frame through a four-way handshake. Additionally, the security establishment process can be performed according to a security scheme not defined in the IEEE 802.11 standard.

[0075] Figure 4 It is a diagram for explaining the backoff process to which the present disclosure can be applied.

[0076] In a wireless LAN system, the basic access mechanism of the Media Access Control (MAC) is the Carrier Sense Multiple Access with Collision Avoidance (CSMA / CA) mechanism. The CSMA / CA mechanism is also known as the Distributed Coordination Function (DCF) of the IEEE 802.11 MAC and basically adopts a "listen before talk" access mechanism. According to this type of access mechanism, before starting to transmit, the AP and / or STA can perform a Clear Channel Assessment (CCA) of sensing the radio channel or medium during a predetermined time interval (e.g., DCF Inter-Frame Space (DIFS)). As a result of the sensing, if it is determined that the medium is idle, frame transmission is started through the corresponding medium. On the other hand, if the medium is detected to be occupied or busy, the corresponding AP and / or STA does not start its own transmission and can set a delay period for medium access (e.g., a random backoff period) and attempt frame transmission after waiting. By applying a random backoff period, since it is expected that multiple STAs will attempt frame transmission after waiting for different time periods, collisions can be minimized.

[0077] In addition, the IEEE 802.11 MAC protocol provides a Hybrid Coordination Function (HCF). The HCF is based on the DCF and the Point Coordination Function (PCF). The PCF is a polling-based synchronous access method and refers to a method in which all receiving APs and / or STAs are periodically polled to receive data frames. In addition, the HCF has Enhanced Distributed Channel Access (EDCA) and HCF Control Channel Access (HCCA). The EDCA is a contention-based access method that provides data frames to multiple users in a directed manner, and the HCCA uses a non-contention-based channel access method that utilizes a polling mechanism. In addition, the HCF includes a medium access mechanism for improving the Quality of Service (QoS) of the wireless LAN and can transmit QoS data during a Contention Period (CP) and a Contention-Free Period (CFP).

[0078] Refer to Figure 4, operations based on a random backoff period will be described. When the occupied / busy medium becomes idle, multiple STAs can attempt to transmit data (or frames). As a method of minimizing collisions, each of the STAs can separately select a random backoff count and attempt to transmit after waiting for the corresponding slot time. The random backoff count has a pseudo-random integer value and can be determined as one of the values that vary from 0 to the value of CW. Here, CW is the contention window parameter value. The CW parameter is given the initial value of CWmin, but can take a value twice as large in the case of a transmission failure (e.g., when an ACK for the transmitted frame is not received). When the CW parameter value reaches CWmax, data transmission can be attempted while maintaining the CWmax value until the data transmission is successful, and when the data transmission is successful, the CWmin value is reset. The values of CW, CWmin, and CWmax are preferably set to 2n - 1 (n = 0, 1, 2,...).

[0079] When the random backoff process starts, the STA continuously monitors the medium during the countdown of the backoff slot according to the determined backoff count value. When monitoring the medium for occupancy, it stops the countdown and waits, and when the medium becomes idle, it resumes the remaining part of the countdown.

[0080] In Figure 4 the example, when the packet to be transmitted arrives at the MAC of STA 3, STA3 can transmit 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 transmitted 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 can perform the countdown of the backoff slot 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, an example is shown 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 while STA2 occupies the medium. When the occupancy of STA2 ends and the medium becomes idle again, STA1 and STA5 wait for DIFS and resume the stopped backoff count. That is, frame transmission can start after counting down the remaining backoff slots for the remaining backoff time. Since the remaining backoff time of STA5 is shorter than the remaining backoff time of STA1, STA5 starts frame transmission. While STA2 occupies the medium, the data to be transmitted can also occur in STA4. From the perspective of STA4, when the medium becomes idle, STA4 can wait for DIFS and then can perform the countdown according to the random backoff count value selected by STA4 and start transmitting the frame. Figure 4The example shows a situation where the remaining backoff time of STA5 accidentally conflicts with the random backoff counter 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 the data transmission fails. In this case, STA4 and STA5 can double the CW value, select a random backoff counter value, and perform countdown. When the medium is occupied due to the transmissions of STA4 and STA5, STA1 waits. When the medium becomes idle, STA1 waits for DIFS, and then starts frame transmission after the remaining backoff time has passed.

[0081] As in Figure 4 the example, a data frame is a frame for transmitting data forwarded to a higher layer, and can be transmitted after a backoff executed after DIFS has elapsed 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 transmitted after a backoff executed after an IFS such as DIFS or Point Coordination Function IFS (PIFS). As subtype frames of the management frame, there are beacons, association requests / responses, re-association requests / responses, probe requests / responses, authentication requests / responses, etc. A control frame is a frame for controlling access to the medium. As subtype frames of the control frame, there are Request to Send (RTS), Clear to Send (CTS), Acknowledgment (ACK), Power Save Poll (PS-Poll), Block Ack (BlockAck), Block ACK Request (BlockACKReq), Null Data Packet Announcement (NDP Announcement), and Trigger, etc. If a control frame is not a response frame to a previous frame, it is transmitted after a backoff executed after DIFS, and if it is a response frame to a previous frame, it is transmitted without performing a backoff after Short IFS (SIFS). The type and subtype of a frame can be identified by the type field and subtype field in the Frame Control (FC) field.

[0082] A Quality of Service (QoS) STA can perform a backoff executed after Arbitration IFS (AIFS) for the access category (AC) to which the frame belongs (i.e., AIFS (where i is a value determined by the AC)), and then can transmit the frame. Here, frames for which AIFS can be used can be data frames, management frames, or control frames other than response frames.

[0083] Figure 5 is a diagram for explaining the CSMA / CA-based frame transmission operation to which the present disclosure can be applied.

[0084] As described above, in addition to the physical carrier sensing of the medium directly by the STA, the CSMA / CA mechanism also includes virtual carrier sensing. Virtual carrier sensing aims to compensate for problems such as the hidden node problem that may occur in medium access. For virtual carrier sensing, the MAC of the STA can use the Network Allocation Vector (NAV). The NAV is a value that indicates to other STAs the remaining time until the medium is available for the current STA using it or the STA authorized to use the medium. Therefore, the value set as the NAV corresponds to the period during which the STA transmitting 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 in the MAC header of the frame.

[0085] In Figure 5 the example, it is assumed that STA1 aims to send data to STA2, and STA3 is in a position where it can overhear some or all of the frames transmitted and received between STA1 and STA2.

[0086] To reduce the possibility of transmission conflicts among multiple STAs in the CSMA / CA-based frame transmission operation, a mechanism using RTS / CTS frames can be applied. In Figure 5 the example, when the transmission of STA1 is being executed, as a result of the carrier sensing of STA3, it can be determined that the medium is in an idle state. That is, STA1 can correspond to a hidden node with respect to STA3. Alternatively, in Figure 5 the example, it can be determined that when the transmission of STA2 is being executed, the carrier sensing result of STA3 indicates that the medium is in an idle state. That is, STA2 can correspond to a hidden node with respect to STA3. By exchanging RTS / CTS frames before data transmission and reception between STA1 and STA2, STAs outside the transmission range of either STA1 or STA2 or STAs outside the carrier sensing range of the transmission from STA1 or STA3 can refrain from attempting to occupy the channel during the data transmission and reception between STA1 and STA2.

[0087] Specifically, STA1 can determine whether the channel is being used through carrier sensing. In terms of physical carrier sensing, STA1 can determine the occupied or idle state of the channel based on the energy level detected in the channel or signal correlation. Additionally, in terms of virtual carrier sensing, STA1 can use the Network Allocation Vector (NAV) timer to determine the channel occupancy state.

[0088] When the channel is in an idle state during DIFS, STA1 can send an RTS frame to STA2 after performing backoff. When STA2 receives the RTS frame, STA2 can send a CTS frame to STA1 as a response to the RTS frame after SIFS.

[0089] If STA3 cannot overhear the CTS frame from STA2 but can overhear the RTS frame from STA1, STA3 can use the duration information included in the RTS frame to set the NAV timer for the transmission period of the frames continuously sent thereafter (e.g., SIFS + CTS frame + SIFS + data frame + SIFS + ACK frame). Alternatively, if STA3 can overhear the CTS frame from STA2, even though STA3 cannot overhear the RTS frame from STA1, STA3 can also use the duration information included in the CTS frame to set the NAV timer for the transmission period of the frames continuously sent thereafter (e.g., SIFS + data frame + SIFS + ACK frame). That is, if STA3 can overhear one or more of the RTS frames or CTS frames 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 use the duration information included in the new frame to update the NAV timer. STA3 does not attempt channel access until the NAV timer expires.

[0090] When STA1 receives a CTS frame from STA2, STA1 can send a data frame to STA2 after SIFS from the time point when the reception of the CTS frame is completed. When STA2 successfully receives the data frame, STA2 can send an ACK frame to STA1 after SIFS as a response to the data frame. When the NAV timer expires, STA3 can determine whether the channel is being used through carrier sensing. When STA3 determines during the DIFS period after the NAV timer expires that the channel is not being used by other terminals, STA3 can attempt channel access after the contention window (CW) based on random backoff has elapsed.

[0091] Figure 6 is a diagram for illustrating an example of the frame structure used in a WLAN system to which the present disclosure can be applied.

[0092] With instructions or primitives (meaning a set of instructions or parameters) from the MAC layer, the PHY layer can prepare the MAC PDU (MPDU) to be transmitted. For example, when receiving a command from the MAC layer to request the start of transmission from the PHY layer, the PHY layer switches to the transmission mode, configures the information (e.g., data) provided from the MAC layer in the form of a frame, and transmits it. Additionally, when the PHY layer detects a valid preamble of the received frame, the PHY layer monitors the header of the preamble and sends a command to the MAC layer notifying the start of reception by the PHY layer.

[0093] In this way, information transmission / reception in a wireless LAN system is performed in the form of frames, and for this purpose, a PHY layer protocol data unit (PPDU) format is defined.

[0094] The basic PPDU may include a Short Training Field (STF), a Long Training Field (LTF), a Signal (SIG) field, and a Data field. The most basic PPDU format (e.g., the non-HT (High Throughput) shown in Figure 7 can consist only of a legacy-STF (L-STF), a legacy-LTF (L-LTF), a legacy-SIG (L-SIG) field, and a Data field. Additionally, depending on the type of PPDU format (e.g., HT Mixed format PPDU, HT Greenfield format PPDU, VHT (Very High Throughput) PPDU, etc.), additional (or different types of) RL-SIG, U-SIG, non-legacy SIG fields, non-legacy STF, non-legacy LTF (i.e., xx-SIG, xx-STF, xx-LTF (e.g., xx is HT, VHT, HE, EHT, etc.)) etc. may be included between the L-SIG field and the Data field.

[0095] The STF is a signal for signal detection, automatic gain control (AGC), diversity selection, precise time synchronization, etc., and the LTF is a signal for channel estimation and frequency error estimation. The STF and LTF can be referred to as signals for synchronization and channel estimation of the OFDM physical layer.

[0096] The SIG field may include various information related to PPDU transmission and reception. For example, the L-SIG field consists of 24 bits, and the L-SIG field may include a 4-bit Rate field, a 1-bit Reserved bit, a 12-bit Length field, a 1-bit Parity field, and a 6-bit Tail field. The RATE field may include information about the modulation and coding rate of the data. For example, the 12-bit Length field may include information about the length or duration of the PPDU. For example, the value of the 12-bit Length field can be determined based on the type of PPDU. For example, for non-HT, HT, VHT, or EHT PPDU, the value of the Length field can be determined as a multiple of 3. For example, for HE PPDU, the value of the Length field can be determined as a multiple of 3 + 1 or 3 + 2.

[0097] The data field may include a SERVICE field, a Physical Layer Service Data Unit (PSDU), and PPDU tail bits, and may also include padding bits if necessary. Some bits of the SERVICE field may be used for synchronization of the descrambler at the receiving end. The PSDU corresponds to the MAC PDU defined in the MAC layer and may include data generated / used in the upper layer. The PPDU tail bits may be used to return the encoder to the 0 state. The padding bits may be used to adjust the length of the data field in predetermined units.

[0098] The MAC PDU is defined according to various MAC frame formats, and the basic MAC frame consists of a MAC header, a frame body, and a Frame Check Sequence (FCS). The MAC frame may be composed of MAC PDUs and transmitted / received through the PSDU of the data part in the PPDU format.

[0099] The MAC header includes a Frame Control field, a Duration / ID field, an Address field, etc. The Frame Control field may include control information required for frame transmission / reception. The Duration / ID field may be set to the time for transmitting the corresponding frame, etc. For details of the Sequence Control, QoS Control, and HT Control sub-fields of the MAC header, refer to the IEEE 802.11 standard document.

[0100] The Null Data PPDU (NDP) format refers to the PPDU format that does not include a data field. In other words, the NDP refers to a frame format that includes the PPDU preamble of the general PPDU format (i.e., L-STF, L-LTF, L-SIG fields, and additional non-conventional SIG, non-conventional STF, non-conventional LTF (if any)) and does not include the remaining part (i.e., the data field).

[0101] Figure 7 FIG. illustrates an example of the PPDU defined in the IEEE 802.11 standard to which the present disclosure can be applied.

[0102] In standards such as IEEE 802.11a / g / n / ac / ax, various types of PPDUs have been used. The basic PPDU format (IEEE 802.11a / g) includes L-LTF, L-STF, L-SIG, and a data field. The basic PPDU format may also be referred to as the non-HT PPDU format (as shown in (a) of Figure 7 ).

[0103] Compared with the basic PPDU format, the HT PPDU format (IEEE 802.11n) additionally includes HT-SIG, HT-STF, and HT-LFT fields. Figure 7The HT PPDU format shown in (b) thereof 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 (not shown) consisting of an HT-GF-STF, HT-LTF1, HT-SIG, one or more HT-LTFs, and a data field, excluding the L-STF, L-LTF, and L-SIG.

[0104] Compared with the basic PPDU format, an example of the VHT PPDU format (IEEE 802.11ac) additionally includes VHT SIG-A, VHT-STF, VHT-LTF, and VHT-SIG-B fields (as shown in Figure 7 (c) thereof).

[0105] Compared with the basic PPDU format, an example of the HE PPDU format (IEEE 802.11ax) additionally includes a repeated L-SIG (RL-SIG), HE-SIG-A, HE-SIG-B, HE-STF, HE-LTF, and packet extension (PE) fields (as shown in Figure 7 (d) thereof). 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 can vary to 8 μs. The extended range (HE ER) SU PPDU format does not include the HE-SIG-B field, and the length of the HE-SIG-A field can vary to 16 μs. For example, the RL-SIG can be configured to be the same as the L-SIG. Based on the presence of the RL-SIG, the receiving STA can know that the received PPDU is an HE PPDU or an EHT PPDU, which will be described later.

[0106] The EHT PPDU format may include Figure 7 the EHT MU (multi-user) in (e) thereof and Figure 7 the EHT TB (trigger-based) PPDU in (f) thereof. The EHT PPDU format is similar to the HE PPDU format in including an RL-SIG following the L-SIG, but may include a U (universal)-SIG, EHT-SIG, EHT-STF, and EHT-LTF following the RL-SIG.

[0107] 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.

[0108] Compared with the EHT MU PPDU, Figure 7 the EHT TB PPDU in (f) omits the EHT-SIG. A STA that receives a trigger for UL MU transmission (e.g., a trigger frame or a triggered response schedule (TRS)) can perform UL transmission based on the EHT TB PPDU format.

[0109] The L-STF, L-LTF, L-SIG, RL-SIG, U-SIG (general signal), and EHT-SIG fields can be encoded and modulated so that even traditional STAs can attempt to demodulate and decode, and can be mapped based on the determined subcarrier frequency spacing (e.g., 312.5 kHz). These can be referred to as pre-EHT modulation fields. Next, the EHT-STF, EHT-LTF, data, and PE fields can be encoded and modulated to be demodulated and decoded by a STA that successfully decodes a non-traditional SIG (e.g., U-SIG and / or EHT-SIG) and obtains the information included in this field, and can be mapped based on the determined subcarrier frequency spacing (e.g., 78.125 kHz). These can be referred to as EHT modulation fields.

[0110] Similarly, in the HE PPDU format, the L-STF, L-LTF, L-SIG, RL-SIG, HE-SIG-A, and HE-SIG-B fields can be referred to as pre-HE modulation fields, and the HE-STF, HE-LTF, data, and PE fields can be referred to as HE modulation fields. Additionally, in the VHT PPDU format, the L-STF, L-LTF, L-SIG, and VHT-SIG-A fields can be referred to as non-VHT modulation fields, and the VHT STF, VHT-LTF, VHT-SIG-B, and data fields can be referred to as VHT modulation fields.

[0111] Included in Figure 7The U-SIG in the EHT PPDU format can be configured based on, for example, two symbols (e.g., two consecutive OFDM symbols). Each symbol (e.g., OFDM symbol) for the U-SIG can have a duration of 4 μs, and the U-SIG can have a total duration of 8 μs. Each symbol of the U-SIG can be used to transmit 26 bits of information. For example, each symbol of the U-SIG can be transmitted and received based on 52 data tones and 4 pilot tones.

[0112] The U-SIG can be constructed in units of 20 MHz. For example, if an 80 MHz PPDU is constructed, the U-SIG can be replicated. That is, the same 4 U-SIGs can be included in the 80 MHz PPDU. A PPDU with a bandwidth exceeding 80 MHz can include different U-SIGs.

[0113] For example, A uncoded bits can be transmitted through the U-SIG. The first symbol of the U-SIG (e.g., the U-SIG-1 symbol) can transmit the first X bits of information out of the total A bits of information, and the second symbol of the U-SIG (e.g., the U-SIG-2 symbol) can transmit the remaining Y bits of information out of the total A bits of information. The A bits of information (e.g., 52 uncoded bits) can include a CRC field (e.g., a 4-bit long field) and a tail field (e.g., a 6-bit long field). For example, the tail field can be used to terminate the trellis structure of the convolutional decoder and can be set to 0.

[0114] The bit information transmitted through the U-SIG can be divided into version-independent bits and version-dependent bits. For example, the U-SIG can be included in Figure 7 a new PPDU format not shown (e.g., the UHR PPDU format), and can be included in the format of the U-SIG field included in the EHT PPDU format and the format of the U-SIG field included in the UHR PPDU format. The version-independent bits can be the same, and some or all of the version-dependent bits can be different.

[0115] For example, the size of the version-independent bits of the U-SIG can be fixed or variable. The version-independent bits can be assigned only to the U-SIG-1 symbol, or assigned to both the U-SIG-1 symbol and the U-SIG-2 symbol. The version-independent bits and the version-dependent bits can be called various names, such as the first control bit and the second control bit.

[0116] For example, the version - independent bits of the U - SIG may include 3 - bit physical layer version identifiers (PHY version identifiers), and this information may indicate the PHY version of the transmitted / received PPDU (e.g., EHT, UHR, etc.). The version - independent bits of the U - SIG may include a 1 - bit UL / DL flag field. The first value of the 1 - bit UL / DL flag field is associated with UL communication, and the second value of the UL / DL flag field is associated with DL communication. The version - independent bits of the U - SIG may include information about the length of the transmission opportunity (TXOP) and information about the BSS color ID.

[0117] For example, the version - related bits of the U - SIG may include information that directly or indirectly indicates the type of the PPDU (e.g., SU PPDU, MU PPDU, TB PPDU, etc.).

[0118] The information required for PPDU transmission and reception may be included in the U - SIG. For example, the U - SIG may also include information about the bandwidth, information about the MCS technique applied to non - traditional SIGs (e.g., EHT - SIG or UHR - SIG, etc.), information indicating whether the DCM (dual - carrier modulation) technique (e.g., a technique for achieving an effect similar to frequency diversity by reusing the same signal on two sub - carriers) is applied to non - traditional SIGs, information about the number of symbols for non - traditional SIGs, information about whether non - traditional SIGs are generated across the entire frequency band.

[0119] Some of the information required for PPDU transmission and reception may be included in the U - SIG and / or non - traditional SIGs (e.g., EHT - SIG or UHR - SIG, etc.). For example, information about the type of non - traditional LTF / STF (e.g., EHT - LTF / EHT - STF or UHR - LTF / UHR - STF, etc.), information about the length of non - traditional LTF and the CP (cyclic prefix) length, information about the GI (guard interval) applicable to non - traditional LTF, information about the preamble punching applicable to the PPDU, information about the resource unit (RU) allocation, etc. may be included only in the U - SIG, only in the non - traditional SIG, or may be indicated by a combination of the information included in the U - SIG and the information included in the non - traditional SIG.

[0120] Preamble punching may represent the transmission of the following PPDU, where there is no signal in one or more frequency units among the bandwidth of the PPDU. For example, the size of the frequency unit (or the resolution of the preamble punching) may be defined as 20 MHz, 40 MHz, etc. For example, preamble punching may be applied to a PPDU bandwidth of a predetermined size or larger.

[0121] In Figure 7In an example, non - traditional SIGs such as HE - SIG - B and EHT - SIG can include control information for receiving STAs. The non - traditional SIG can be sent on at least one symbol, and one symbol can have a length of 4 μs. Information about the number of symbols for EHT - SIG can be included in a previous SIG (e.g., HE - SIG - A, U - SIG, etc.).

[0122] Non - traditional SIGs such as HE - SIG - B and EHT - SIG can include a common field and user - specific fields. The common field and user - specific fields can be encoded separately.

[0123] In some cases, the common field can be omitted. For example, in a compressed mode that does not apply OFDMA (Orthogonal Frequency Division Multiple Access), the common field can be omitted, and multiple STAs can receive a PPDU (e.g., the data field of the PPDU) through the same frequency band. In a non - compressed mode that applies OFDMA, multiple users can receive a PPDU (e.g., the data field of the PPDU) through different frequency bands.

[0124] The number of user - specific fields can be determined based on the number of users. One user block field can include up to two user fields. Each user field can be associated with MU - MIMO allocation or can be associated with non - MU - MIMO allocation.

[0125] The common field can include CRC bits and tail bits. The length of the CRC bits can be determined to be 4 bits, and the length of the tail bits can be determined to be 6 bits and set to 000000. The common field can include RU allocation information. The RU allocation information can include information about the positions of the RUs assigned to multiple users (i.e., multiple receiving STAs).

[0126] An RU can include multiple sub - carriers (or tones). When sending signals to multiple STAs based on OFDMA technology, RUs can be used. Additionally, even when sending signals to one STA, RUs can be defined. Resources for non - traditional STF, non - traditional LTF, and data fields can be allocated in units of RUs.

[0127] The RU of an applicable size can be defined according to the PPDU bandwidth. The RU can be defined identically or differently for the applied PPDU format (e.g., HE PPDU, EHT PPDU, UHR PPDU, etc.). For example, in the case of an 80 MHz PPDU, the RU layouts of the HE PPDU and the EHT PPDU can be different. The applicable RU size, the number and position of RUs, the DC (direct current) subcarrier position and number, the null subcarrier position and number, the guard subcarrier position and number, etc. for each PPDU bandwidth can be referred to as a tone plan. For example, the tone plan for high bandwidth can be defined in the form of multiple iterations of a low-bandwidth tone plan.

[0128] RUs of various sizes can be defined as 26-tone RUs, 52-tone RUs, 106-tone RUs, 242-tone RUs, 484-tone RUs, 996-tone RUs, 2×996-tone RUs, 3×996-tone RUs, etc. An MRU (multi-RU) is different from multiple individual RUs and corresponds to a set of subcarriers composed of multiple RUs. For example, an MRU can be defined as 52 + 26 tones, 106 + 26 tones, 484 + 242 tones, 996 + 484 tones, 996 + 484 + 242 tones, 2×996 + 484 tones, 3×996 tones, or 3×996 + 484 tones. Additionally, the multiple RUs constituting an MRU can be continuous or non-continuous in the frequency domain.

[0129] The specific size of an RU can be reduced or extended. Therefore, the specific size (i.e., the number of corresponding tones) of each RU in this disclosure is illustrative rather than restrictive. Additionally, in this disclosure, within a predetermined bandwidth (e.g., 20 MHz, 40 MHz, 80 MHz, 160 MHz, 320 MHz...), the number of RUs can vary according to the RU size.

[0130] Figure 7 The name of each field in the PPDU format is exemplary, and the scope of this disclosure is not limited by these names. Additionally, the examples of this disclosure can be applied to Figure 7 the PPDU format shown in Figure 7 and new PPDU formats that exclude some fields and / or add some fields based on the

[0131] Figure 8 is a diagram illustrating an example format of a trigger frame to which this disclosure can be applied.

[0132] The trigger frame can allocate resources for the transmission of one or more TB PPDUs and request the transmission of TB PPDUs. The trigger frame can also include other information required by the STA to send a TB PPDU as a response. The trigger frame can include common information and a user information list field in the frame body.

[0133] The common info field is information that is typically applied to the transmission of one or more TB PPDUs requested by the trigger frame, such as trigger type, UL length, presence or absence of subsequent trigger frames (e.g., more TFs), CS (channel sensing) request, UL BW (bandwidth), HE / EHT P160, special user information field flag, etc.

[0134] The 4-bit trigger type subfield can have values from 0 to 15. Among them, the 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 acknowledgment 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 the values 8 to 15 are defined as reserved.

[0135] Among the common information, the trigger-related common information subfield can include information optionally included based on the trigger type.

[0136] The special user information field can be included in the trigger frame. The special user information field does not include user-specific information but includes extended common information not provided in the common information field.

[0137] The user information list includes zero or more user information fields. Figure 8 An example of the EHT variant user information field format is shown.

[0138] The AID12 subfield basically indicates that it is a user information field of the STA with the corresponding AID. In addition, if the AID12 field has a specific predetermined value, it can be used for other purposes, such as allocating a random access (RA)-RU or being configured as a special user information field. The special user information field is a user information field that does not include user-specific information but includes extended common information not provided in the common information field. For example, the special user information field can be identified by the AID12 value 2007, and the special user information field flag subfield within the common information field can indicate whether the special user information field is included.

[0139] 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 and the UL BW subfield of the common information field.

[0140] Structure of Aggregate PPDU (A-PPDU)

[0141] To improve the efficiency and throughput in a wireless LAN system, A-PPDU transmission may be defined, in which PPDUs of different formats / versions are transmitted simultaneously.

[0142] An A-PPDU may correspond to a new format that combines multiple PPDU formats in the frequency domain. For example, referring to Figure 9 , in A-PPDU transmission, a first sub-PPDU (S-PPDU) format may be transmitted in a first frequency band (e.g., 160 MHz), a second S-PPDU format may be transmitted in a second frequency band (e.g., 80 MHz), and a third S-PPDU format may be transmitted in a third frequency band (e.g., 80 MHz).

[0143] However, this is only one implementation, and in A-PPDU transmission, a first S-PPDU format may be transmitted in the first frequency band, and a second S-PPDU format may be transmitted in the second frequency band.

[0144] Each S-PPDU that constitutes an A-PPDU may be a PPDU of a different format. For example, each S-PPDU may be one of a HE PPDU, an EHT PPDU, and a new format of PPDU after EHT (hereinafter referred to as "UHR") (i.e., the next version of the PPDU).

[0145] Here, each of the HE PPDU, EHT PPDU, and UHR PPDU may include a HE MU PPUD, an EHT MUPPUD, and a UHR MU PPDU. The UHR MU PPDU may have a structure similar to that of the EHT MU PPDU of OFDMA transmission or MU MIMO transmission. However, the dependent field of the U-SIG field of the UHR MU PPDU may be different from the dependent field of the U-SIG field of the EHTMU PPDU. In addition, the EHT MU PPUD may include a UHR SIG field instead of an EHT SIG field.

[0146] Intercepted A-PPDU

[0147] A STA may have a Transmission Opportunity (TXOP). Here, a TXOP refers to a time interval during which a specific STA has the permission to initiate a frame exchange sequence over a Wireless Medium (WM). A TXOP may be defined by a start time (during which the STA may have the permission) and a maximum duration value.

[0148] For example, as shown in (a) of Figure 10 , it is assumed that during a TXOP, latency-sensitive (LS) traffic arrives while the STA is transmitting non-LS traffic. If the STA continuously transmits non-LS traffic within the TXOP, the transmission of the LS traffic has to wait until the end of the TXOP, thus requiring channel contention.

[0149] To reduce the latency of LS traffic, a preemptable PPDU can be introduced. Thus, LS traffic can be transmitted within the current TXOP (i.e., Figure 10 TXOP1 in (a) of

[0150] For example, as shown in (b) of Figure 10 , when LS traffic arrives while PPDU-3 is being transmitted in an 80 MHz bandwidth, PPDU-4 based on the LS traffic can be transmitted within that bandwidth.

[0151] As an example of the present disclosure, for a non-LS PPDU with a length of 4 ms, the transmitting STA may choose to interrupt the transmission and reassign the TXOP to the LS traffic.

[0152] For this purpose, as shown in (c) of Figure 10 , when the LS traffic does not arrive, the PHY layer can encode the 4 ms PPDU payload into 4 PPDU payloads (i.e., each PPDU payload is 1 ms).

[0153] As shown in (d) of Figure 10 , when LS traffic arrives during the transmission of non-LS traffic, the PHY layer can terminate the transmission of the non-LS traffic at the nearest boundary with a PPDU end marker. The receiving STA can forward the received segment to the upper layer.

[0154] In another example of the present disclosure, the transmitting STA may choose to terminate the ongoing transmission and then transmit the LS traffic.

[0155] For example, as shown in (a) of Figure 11 , if the non-LS traffic does not arrive, the PHY layer can encode the PPDU and wait for the ACK reception.

[0156] As shown in Figure 11 (b) of FIG., when the LS traffic arrives during the transmission of non-LS traffic, the PHY layer may insert an end-of-PPDU sequence marker at the end of the PPDU. Accordingly, subsequent frame exchanges may be stopped, and the sender STA may send the LS traffic.

[0157] If an end-of-PPDU sequence marker is detected at the end of the PPDU, the receiving STA may expect to receive an LS PPDU after SIFS without sending a BA.

[0158] In another example of the present disclosure, the sender STA may choose to immediately stop the currently ongoing transmission.

[0159] For example, as shown in Figure 11 (c) of FIG., if the LS traffic does not arrive, the PHY layer may encode the PPDU and wait for the ACK reception.

[0160] As shown in Figure 11 (d) of FIG., when the LS traffic arrives, the PHY layer may stop the current transmission with the PPDU end marker and send the LS traffic after SIFS. The receiving STA may remove all or part of the received bits depending on whether the entire MPDU has been received.

[0161] SST (Sub-Channel Selective Transmission)

[0162] SST may include dynamically changing the primary channel within the total bandwidth. For example, the SST operation may include operating under the assumption that only a portion of the total bandwidth is full bandwidth.

[0163] As an example of the present disclosure, SST may be applied based on the Figure 12 subchannel selective transmission (SST) operation elements illustrated in FIG.

[0164] The format of the SST operation elements in existing wireless LAN systems may include an 8-bit element ID field, an 8-bit length field, an 8-bit SST-enabled channel bitmap field, a 3-bit primary channel offset field, a 1-bit SST channel unit field, and 4-bit reserved bits.

[0165] The element ID field is used to identify the element of the format, and the length field may indicate the number of octets of the element excluding the element ID field and the length field.

[0166] The SST-enabled channel bitmap field may include a bitmap indicating the channels enabled for SST operation. Each bit of the bitmap corresponds to one channel with a width equal to the value of the SST channel unit field, and the least significant bit (LSB) may correspond to the lowest-numbered subchannel in the SST-enabled channel bitmap field.

[0167] The channel number of each channel in the SST-enabled channel bitmap field can be equal to the PCN minus (-) the OPC plus (+) the POS, where the PCN is the value of the primary channel number subfield of the most recently transmitted S1G operation element. The OPC is the offset of the primary channel relative to the lowest-numbered subchannel in the bitmap specified by the value of the primary channel offset field. The POS is the position of the channel in the bitmap.

[0168] Setting the bit position in the bitmap to 1 can indicate that the subchannel is enabled for SST operation, but according to the rules defined in the specification, transmissions from SST STAs on that subchannel are allowed. One or more bits in the bitmap can be equal to 1.

[0169] The primary channel offset field can indicate the relative position of the primary channel with respect to the lowest-numbered channel in the SST-enabled channel bitmap field. For example, setting the primary channel offset field to 2 can indicate that the primary channel is the third subchannel in the SST-enabled channel bitmap.

[0170] The SST channel unit field can indicate the channel width unit of each SST channel. Setting the field to 1 can indicate that the channel width unit is 1 MHz, and setting the field to 2 can indicate that the channel width unit is 2 MHz.

[0171] In the following, the configuration of a trigger frame for an A-PPDU transmission enabling interception and its related processes, as an embodiment of the present disclosure, are described to solve the transmission delay problem of delay-sensitive traffic.

[0172] Method for Transmitting and Receiving A-PPDU Based on Trigger Frame

[0173] As described above, intercepted A-PPDUs can be introduced to prevent delays in A-PPDU transmissions. This is a method of sending LS traffic within an A-PPDU through a specific channel using a preemptive PPDU merging method when LS traffic arrives during an A-PPDU transmission.

[0174] For example, the above method can include a method in which the sub-PPDU transmission of the STA among the STAs assigned to each sub-PPDU transmission within the A-PPDU is stopped, and the channel is used to send LS traffic to the STA in the form of an intercepted PPDU. In the case of the above method, an instruction regarding the channel to be used for sending the intercepted PPDU during an A-PPDU transmission may not be required.

[0175] However, if no sub-PPDU is sent to the STA where LS traffic has occurred, it may be necessary to pre-determine a specific channel for sending the intercepted PPDU.

[0176] Additionally or alternatively, the STA may indicate in advance that a specific sub-PPDU within the A-PPDU is short, and thus the channel can be used for LS traffic transmission from a specific timing.

[0177] Additionally or alternatively, a specific channel may be configured / defined to be used only for LS traffic transmission when transmitting an A-PPDU. For example, only dummy signals may be transmitted on the specific channel and may be used for LS traffic transmission only when LS traffic occurs.

[0178] Figure 13 is a flowchart for explaining a method for a first STA to transmit and receive a PPDU according to an embodiment of the present disclosure. In Figure 13 and Figure 14 each of the first STA and the second STA may be one of the APs among the non-AP STAs.

[0179] The first STA may receive a trigger frame for transmitting an aggregated physical layer protocol data unit (A-PPDU) from the second STA (S1310).

[0180] As an example of the present disclosure, the trigger frame may include first information related to at least one frequency resource unit for latency-sensitive (LS) data transmission and second information related to the timing for LS data transmission.

[0181] Specifically, the trigger frame may include at least one of a common information field, an STA information field, or a special STA information field. Also, the first information may be included in the special STA information field or the common information field, and the second information may be indicated by a latency-sensitive traffic transmission timing sub-field included in the special STA information field of the trigger frame.

[0182] As an example of the present disclosure, the first information may be indicated by i) an RU allocation sub-field and ii) a P (primary) S (secondary) 160 sub-field or a PS320 sub-field included in the special STA information field.

[0183] As an example of the present disclosure, the common information field may include a trigger type sub-field, and the trigger type sub-field may include information indicating that the trigger frame is a trigger frame for A-PPDU transmission (or / and, intercepted PPDU transmission).

[0184] As an example of the present disclosure, based on the allocation of a specific channel by information related to sub-channel selective transmission, all or part of the specific channel may be indicated as at least one frequency resource unit for LS data transmission by the first information.

[0185] In addition, the common information field may include at least one of the following: an A-PPDU structure field indicating the structure of the A-PPDU, a field indicating the bandwidth of at least one sub-PPDU included in the A-PPDU, or a field indicating the length of the A-PPDU.

[0186] The first STA may receive an A-PPDU from the second STA based on a trigger frame (S1320). That is, the first STA may receive an A-PPDU from the second STA based on the information included in the trigger frame.

[0187] As an example of the present disclosure, a dummy signal may be transmitted in at least one frequency resource unit based on the absence of LS data.

[0188] Moreover, the A-PPDU may include a plurality of sub-PPDUs. Based on the arrival of LS data when receiving a specific sub-PPDU corresponding to at least one resource unit among the plurality of received sub-PPDUs, the reception of the specific sub-PPDU is stopped, and the first STA may receive LS data through at least one resource unit based on the first information and the second information.

[0189] In Figure 13 the example described, the method performed by the first STA may be performed by Figure 1 the first device (100) of Figure 1 For example, one or more processors (102) of the first device (100) of

[0190] may receive a trigger frame for A-PPDU transmission from the second STA through one or more transceivers (106). One or more processors (102) may be configured to receive an A-PPDU from the second STA through one or more transceivers (106) based on the trigger frame. Figure 13 In addition, one or more memories (104) of the first device (100) may store instructions for performing the method described in the example of

[0191] Figure 14 is a flowchart illustrating a method for a second STA to transmit and receive a PPDU according to an embodiment of the present disclosure.

[0192] The second STA may send a trigger frame including information related to A-PPDU transmission to the first STA (S1410).

[0193] The structure of the trigger frame and the information included in the trigger frame have been described with reference to Figure 13 and thus any repeated description will be omitted.

[0194] The second STA may send an A-PPDU to the first STA based on the trigger frame (S1420).

[0195] For example, when LS traffic is generated / arrives while an A-PPDU is being sent, the second STA may send the LS traffic to the first STA based on at least one of first information related to at least one frequency resource unit for LS data transmission and second information related to the timing for LS data transmission.

[0196] In Figure 14 the example described by the method performed by the second STA can be performed by Figure 1 the second device (200). For example, Figure 13 one or more processors (202) of the second device (200) may be configured to send a trigger frame to the first STA via one or more transceivers (206). One or more processors (202) of the second device (200) may be configured to send an A-PPDU to the first STA based on the trigger frame via one or more transceivers (206).

[0197] In addition, one or more memories (204) of the second device (200) may store instructions for performing the method described in Figure 14 the example when executed by one or more processors (202).

[0198] Hereinafter, the structure of the trigger frame for implementing intercepted A-PPDU transmission and the related processes are described in detail.

[0199] Embodiment 1

[0200] A trigger-like frame may be used to indicate the channel and / or timing for LS traffic transmission during A-PPDU transmission. That is, a trigger-like frame may be sent, and an A-PPDU may be sent after SIFS. The trigger-like frame may include information related to the channel and / or timing for LS traffic transmission.

[0201] When describing the present disclosure, a frame such as a trigger may be in the form of, but not limited to, a trigger frame. A separate frame containing information indicating the channel and / or timing for LS traffic transmission may also be sent before A-PPDU transmission.

[0202] For ease of explanation of the present disclosure, a frame including information indicating the channel and / or timing for LS traffic transmission before A-PPDU transmission is referred to as a trigger frame in the following description. That is, in the following description, the trigger frame may be replaced by a separate frame (e.g., a frame related to A-PPDU transmission), a trigger-like frame, etc.

[0203] As an example of the present disclosure, the trigger frame may include at least one of the following: information indicating the transmission of an A-PPDU, the structure of the A-PPDU, an indication of the bandwidth associated with the A-PPDU transmission, information for allocating a specific channel to each STA, or information indicating a specific channel / timing to be used for LS traffic transmission.

[0204] As an example of the present disclosure, as Figure 15 shown, a trigger frame may be sent, and after the SIFS, an A-PPDU based on the trigger frame may be sent. The A-PPDU may send sub-PPDUs corresponding to each bandwidth. For example, when LS traffic arrives, the transmission of sub-PPDU-3 may be stopped, and the LS traffic may be sent based on the information included in the trigger frame.

[0205] The trigger frame may include a common information field, an STA information field, and a special STA information field. The configuration of each field of the trigger frame is described below.

[0206] Embodiment 2-1

[0207] Embodiment 2-1 relates to the configuration of the common information field of the trigger frame.

[0208] As an example of the present disclosure, the common information field of the trigger frame may include a trigger type sub-field indicating the subtype (or variant) of the trigger frame. The trigger type sub-field may include information indicating that the trigger frame is a trigger frame for DL A-PPDU transmission.

[0209] For example, if the value of the trigger type sub-field is set to one of 8 to 15, this may mean that the trigger frame is a trigger frame for DL A-PPDU transmission.

[0210] As an example of the present disclosure, the common information field of the trigger frame may include an A-PPDU structure sub-field. The A-PPDU structure sub-field may indicate the A-PPDU structure (e.g., the configuration of the sub-PPDUs), etc.

[0211] Additionally or alternatively, the common information field of the trigger frame may include an A-PPDU structure sub-field and one or more sub-PPDU bandwidth sub-fields. The bandwidth of the A-PPDU and / or one or more sub-PPDUs constituting the A-PPDU may be indicated by the A-PPDU structure sub-field and one or more sub-PPDU bandwidth sub-fields.

[0212] For example, based on the number and type of sub-PPDUs indicated in the A-PPDU structure field, the sub-PPDU bandwidth field may be composed of multiple fields.

[0213] As another example, the bandwidth of the sub-PPDU can be pre-determined based on the A-PPDU structure and the bandwidth. In this case, the sub-PPDU bandwidth field may not be included in the common information field of the trigger frame.

[0214] As an example of the present disclosure, the common information field of the trigger frame may include a DL length sub-field. The DL length sub-field may indicate the length of the DL A-PPDU transmitted based on the trigger frame (taking into account the longest sub-PPDU).

[0215] In addition, the common information field of the trigger frame may include some reserved sub-fields.

[0216] Embodiment 2-2

[0217] Embodiment 2-2 relates to the configuration of the STA information field of the trigger frame.

[0218] The STA information field may include an AID12 sub-field indicating a specific STA. For example, the STA information field including the AID12 sub-field indicating a specific STA may include information for that specific STA.

[0219] As an example of the present disclosure, the STA information field may only indicate UHR STAs, but is not limited thereto, and may also indicate other types of STAs.

[0220] The STA information field may include an RU allocation sub-field and a PS160 sub-field. Based on the RU allocation sub-field and the PS160 sub-field, the type of the sub-PPDU allocated to the corresponding STA and the RU / MRU information associated with the corresponding sub-PPDU can be indicated.

[0221] For example, when the 480 / 640 MHz bandwidth is defined / introduced, the STA information field may include a PS320 sub-field. The PS320 sub-field may indicate whether the bandwidth allocated to the corresponding sub-PPDU and / or the corresponding STA is the primary 320 MHz or the secondary 320 MHz. The corresponding STA may perform channel switching and wait in advance using at least one of the RU allocation sub-field, the PS160 sub-field, or the PS320 sub-field.

[0222] As an example of the present disclosure, the STA information field may include specific sub-fields for indicating coding, the number of spatial streams, the modulation and coding scheme (MCS), etc. However, coding, the number of spatial streams, MCS, etc. may be indicated in the SIG field of the A-PPDU, and the STA information field of the trigger frame may not include the above information.

[0223] As another example, if a specific channel is pre-allocated to each STA by SST or the like, the STA information field may not include an RU allocation sub-field because the RU allocation information is indicated in the SIG field when transmitting an A-PPDU.

[0224] As another example, if a specific channel is pre-allocated to each STA by SST or the like, the trigger frame may not include an STA information field that contains information about a specific STA.

[0225] That is, the trigger frame may only include information related to the channel and / or timing allocation of the intercepted A-PPDU. Also, the trigger type sub-field in the common information field of the trigger frame may indicate that the trigger frame is a trigger frame for the intercepted DL A-PPDU.

[0226] Embodiment 2-3

[0227] Embodiment 2-3 relates to the configuration of a special STA information field of a trigger frame.

[0228] The special STA information field of the trigger frame may include an AID12 sub-field. When the AID12 sub-field is set to a specific value (e.g., 2007, etc.), this may indicate that the special STA information field may include information for LS traffic.

[0229] The special STA information field may include an RU allocation sub-field and a PS160 sub-field. Based on the RU allocation sub-field and the PS160 sub-field, the type of sub-PPDU associated with the intercepted PPDU (allocated to the corresponding STA) and the RU / MRU information associated with the corresponding sub-PPDU can be indicated.

[0230] For example, when a 480 / 640 MHz bandwidth is defined / introduced, the STA information field may include a PS320 sub-field. The PS320 sub-field may indicate whether the bandwidth allocated to the corresponding intercepted PPDU and / or the corresponding STA is the primary 320 MHz or the secondary 320 MHz.

[0231] Here, the intercepted PPDU can be allocated to a specific channel / RU / MRU within the channel of the transmitting sub-UHR PPDU (i.e., a sub-PPDU based on the UHR format). Also, the intercepted A-PPDU (or sub-PPDU) can be configured in the UHR PPDU format.

[0232] Additionally or alternatively, assume a situation where the transmission of a specific sub-PPDU can be terminated in advance because the specific sub-PPDU is a short packet. Here, compared with the length of the A-PPDU, the amount of data corresponding to a specific STA may be small, so the data sent to the specific STA can be defined as a short packet. As another example, if the length of a specific sub-PPDU is less than a threshold, the specific sub-PPDU can be defined as a short packet.

[0233] Here, a specific channel / RU / MRU within the channel can be indicated to be used for LS traffic transmission based on the RU allocation sub-field and the PS160 / PS320 sub-field included in the special STA information field.

[0234] Additionally or alternatively, the special STA information field may include a delay-sensitive traffic transmission timing sub-field. The delay-sensitive traffic transmission timing sub-field can indicate the timing when LS traffic transmission is possible.

[0235] If there is no specific LS traffic after the transmission of the sub-PPDU of the short packet is completed, a dummy signal can be sent on the corresponding channel / RU / MRU.

[0236] Additionally or alternatively, the specific channel / RU / MRU indicated via the RU allocation sub-field and the PS160 / PS320 sub-field can be allocated only for LS traffic transmission.

[0237] Here, if there is no LS traffic during the DL A-PPDU transmission, a dummy signal can be sent in the channel / RU / MRU indicated by the RU allocation sub-field and the PS160 / PS320 sub-field.

[0238] As an example of the present disclosure, when a specific STA sends periodic LS traffic, a specific channel can be allocated to the STA through the SST. And, through the above RU allocation sub-field and PS160 / PS320 sub-field, it can be indicated that the channel / RU / MRU within the specific channel is only used for LS traffic transmission.

[0239] As an example of the present disclosure, if the trigger frame does not include a STA information field containing information for a specific STA, the information for LS traffic may not be included in the special STA information field.

[0240] Here, all sub-fields other than the AID12 sub-field among the sub-fields described as included in the special STA information field can be included in the common information field. That is, the trigger frame may not include the STA information field and the special user field.

[0241] The above-described embodiments combine the elements and features of the present disclosure in a predetermined form. Unless otherwise explicitly mentioned, each element or feature should be considered optional. Each element or feature can be implemented in a form that does not combine with other elements or features. Additionally, embodiments of the present disclosure can include combining some elements and / or features. The order of operations described in the embodiments of the present disclosure can be changed. Some elements or features of one embodiment can be included in other embodiments, or can be replaced with corresponding elements or features of other embodiments. Obviously, embodiments can include combining claims that do not have an explicit citation relationship in the claims, or can be included as new claims through amendment after the application.

[0242] It is clear to those skilled in the relevant art that the present disclosure can be implemented in other specific forms without exceeding the essential characteristics of the present disclosure. Therefore, the above detailed description should not be construed restrictively in every aspect, but should be considered illustrative. The scope of the present disclosure should be determined by a reasonable interpretation of the appended claims, and all changes within the equivalent scope of the present disclosure are included within the scope of the present disclosure.

[0243] The scope of the present disclosure includes software or machine-executable commands (e.g., operating systems, applications, firmware, programs, etc.) that perform operations according to the methods of various embodiments in a device or computer, and non-transitory computer-readable media that enable the software or commands, etc. to be stored and executable in the device or computer. Commands that can be used to program a processing system for performing 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 can include high-speed random access memories, such as DRAM, SRAM, DDR RAM, or other random access solid-state storage devices, but is not limited thereto, and it can include non-volatile memories, such as one or more disk storage devices, optical disk storage devices, flash memory devices, or other non-volatile solid-state storage devices. The memory optionally includes one or more storage devices located remotely from the processor. The memory, or alternatively, the non-volatile memory device in the memory, includes a non-transitory computer-readable storage medium. The features described in the present disclosure can be stored in any kind of machine-readable medium to control the hardware of the processing system, and can be integrated into software and / or firmware that allows the processing system to interact with other mechanisms using the results from the embodiments of the present disclosure. Such software or firmware can include application code, device drivers, operating systems, and execution environments / containers, but is not limited thereto.

[0244] Industrial Applicability

[0245] The method proposed by the present disclosure is mainly described based on examples applied to IEEE 802.11-based systems (5G systems), but can be applied to various WLANs or wireless communication systems other than IEEE 802.11-based systems.

Claims

1. A method performed by a first station STA in a wireless LAN system, the method comprising the steps of: receiving, from a second STA, a trigger frame for transmitting an aggregated physical layer protocol data unit A-PPDU; and receiving, from the second STA, an A-PPDU based on the trigger frame, wherein the trigger frame includes first information related to at least one frequency resource unit for latency-sensitive LS data transmission and second information related to the timing for the LS data transmission.

2. The method according to claim 1, wherein the trigger frame includes at least one of a common information field, a STA information field, or a special STA information field, and the first information is included in the special STA information field or the common information field.

3. The method according to claim 2, wherein the first information is indicated by i) a resource unit RU allocation subfield and ii) a primary P secondary S160 subfield or a PS320 subfield included in the special STA information field.

4. The method according to claim 3, wherein dummy signals are transmitted in at least one frequency resource unit based on the absence of the LS data.

5. The method according to claim 3, wherein based on a specific channel being allocated by information related to subchannel selective transmission, all or part of the specific channel is indicated by the first information as at least one frequency resource unit for the LS data transmission.

6. The method according to claim 2, wherein the common information field includes at least one of an A-PPDU structure field indicating the structure of the A-PPDU, a field indicating the bandwidth of at least one sub-PPDU included in the A-PPDU, or a field indicating the length of the A-PPDU.

7. The method according to claim 2, wherein the common information field includes a trigger type subfield, and the trigger type subfield includes information indicating that the trigger frame is a trigger frame for transmitting the A-PPDU.

8. The method according to claim 2, wherein the special STA information field includes a latency-sensitive traffic transmission timing subfield, and the second information is indicated by the latency-sensitive traffic transmission timing subfield.

9. The method according to claim 1, wherein the A-PPDU includes a plurality of sub-PPDUs, and based on the LS data arriving when receiving a specific sub-PPDU corresponding to the at least one resource unit among the plurality of sub-PPDUs received, the reception of the specific sub-PPDU is stopped, and the LS data is received through the at least one resource unit based on the first information and the second information.

10. A first station STA operating in a wireless LAN system, the first STA comprising: at least one transceiver; and at least one processor connected to the at least one transceiver, wherein the at least one processor is configured to: receive, through the at least one transceiver, a trigger frame for transmitting an aggregated physical layer protocol data unit A-PPDU from a second STA; and Receiving an A-PPDU from the second STA based on the trigger frame by means of the at least one transceiver wherein the trigger frame includes first information related to at least one frequency resource unit for latency-sensitive LS data transmission and second information related to the timing for the LS data transmission.

11. A method performed by a second station STA in a wireless LAN system, the method comprising the steps of: Sending a trigger frame for transmitting an aggregated physical layer protocol data unit A-PPDU to a first STA; and Sending an A-PPDU to the first STA based on the trigger frame, wherein the trigger frame includes first information related to at least one frequency resource unit for latency-sensitive LS data transmission and second information related to the timing for the LS data transmission.

12. A second station STA operating in a wireless LAN system, the second STA comprising: At least one transceiver; and At least one processor connected to the at least one transceiver, wherein the at least one processor is configured to: Send a trigger frame for transmitting an aggregated physical layer protocol data unit A-PPDU to a first STA by means of the at least one transceiver; and Send an A-PPDU to the first STA based on the trigger frame by means of the at least one transceiver, wherein the trigger frame includes first information related to at least one frequency resource unit for latency-sensitive LS data transmission and second information related to the timing for the LS data transmission.

13. A processing device configured to control a first station STA in a wireless LAN system, the processing device comprising: At least one processor; and At least one computer memory operatively connected to the at least one processor and storing instructions that, when executed by the at least one processor, perform operations including: Receiving a trigger frame for transmitting an aggregated physical layer protocol data unit A-PPDU from a second STA; and Receiving an A-PPDU from the second STA based on the trigger frame, wherein the trigger frame includes first information related to at least one frequency resource unit for latency-sensitive LS data transmission and second information related to the timing for the LS data transmission.

14. At least one non-transitory computer-readable medium storing at least one instruction, wherein the at least one instruction executable by at least one processor controls a device in a wireless LAN system to: Receive a trigger frame for transmitting an aggregated physical layer protocol data unit A-PPDU from a second STA; and Receive an A-PPDU from the second STA based on the trigger frame, wherein the trigger frame includes first information related to at least one frequency resource unit for latency-sensitive LS data transmission and second information related to the timing for the LS data transmission.

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