Method and apparatus for triggering uplink preemption in wireless lan system

Abstract

A method and apparatus for triggering uplink preemption in a wireless LAN system are disclosed. According to an embodiment of the present invention, the method can include receiving, by a station (STA), an UL preemption trigger frame for allowing UL preemption from an AP, and transmitting, by the station (STA), an UL preemption request in response to the UL preemption trigger frame based on the presence of UL preemption data.

Description

Technical Field

[0001] This disclosure relates to a method and apparatus for sending and receiving trigger frames in a wireless local area network (WLAN) system to allow uplink preemption. Background Technology

[0002] New technologies have been introduced to Wireless LANs (WLANs) to improve transmission rates, increase bandwidth, improve reliability, reduce errors, and reduce latency. Within WLAN technologies, the IEEE 802.11 series of standards can be referred to as Wi-Fi. For example, recent technologies introduced to WLAN include enhancements to the Very High Throughput (VHT) of the 802.11ac standard and enhancements to the High Efficiency (HE) of the IEEE 802.11ax standard.

[0003] To provide a more robust wireless communication environment, enhancement technologies for EHT (Extreme High Throughput) are being discussed. For example, technologies are being researched for multi-access point (AP) coordination and multiple-input multiple-output (MIMO) to support increased bandwidth, efficient utilization of multiple bands, and increased spatial flow. In particular, various technologies are being investigated to support low-latency or real-time services. Furthermore, new technologies to support Ultra-High Reliability (UHR) through improvements or extensions to EHT technologies are being discussed. Summary of the Invention

[0004] Technical issues

[0005] The technical objective of this disclosure is to provide a method and apparatus for sending and receiving trigger frames to allow uplink preemption of one or more stations (STAs) within a transmission opportunity (TXOP) acquired by an access point (AP).

[0006] Furthermore, another technical objective of this disclosure is to provide a method and apparatus for sending and receiving responses to trigger frames to allow uplink preemption.

[0007] The technical objectives achieved through this disclosure are not limited to those described above, 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] A method according to one aspect of this disclosure may include: a station (STA) receiving a UL preemption trigger frame from an access point (AP) to allow uplink (UL) preemption; and the STA sending a UL preemption request in response to the UL preemption trigger frame based on the presence of UL preemption data. The UL preemption trigger frame may include an indication that the UL preemption trigger frame is an indication to trigger a UL preemption request from one or more STAs intending to send UL preemption data within a transmission opportunity (TXOP) obtained by the AP.

[0010] A method according to one aspect of this disclosure may include: sending a UL preemption trigger frame from an access point (AP) to multiple stations (STAs) to allow uplink (UL) preemption; and receiving a UL preemption request from one or more STAs in response to the UL preemption trigger frame. The UL preemption trigger frame may include an indication that the UL preemption trigger frame is an indication to trigger a trigger frame from one or more STAs intending to send UL preemption data within a transmission opportunity (TXOP) obtained by the AP to send a UL preemption request.

[0011] Beneficial effects

[0012] According to embodiments of this disclosure, STAs that have not yet acquired a transmission opportunity (TXOP) can also quickly transmit uplink data (e.g., low-latency packets, etc.), thereby reducing latency and improving wireless communication efficiency.

[0013] Furthermore, according to embodiments of this disclosure, the AP can determine whether UL preemption data exists before transmitting UL preemption data, thereby improving wireless communication efficiency.

[0014] The effects achievable by this disclosure are not limited to those described above, and other effects not described herein can be clearly understood by those skilled in the art from the following description. Attached Figure Description

[0015] The accompanying drawings, included as part of the detailed description for understanding this disclosure, provide embodiments of the disclosure and describe the technical features of the disclosure through detailed description.

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

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

[0018] Figure 3 It is a diagram used to describe the link setup process to which this disclosure can be applied.

[0019] Figure 4 It is a diagram used to describe the retreat process to which this disclosure can be applied.

[0020] Figure 5 This is a diagram used to describe the CSMA / CA-based frame transmission operation to which this disclosure can be applied.

[0021] Figure 6 This is a diagram illustrating an example of a frame structure that can be used in a WLAN system to which this disclosure may be applied.

[0022] Figure 7 This is a diagram illustrating an example of a PPDU that can be applied in the IEEE 802.11 standard of this disclosure.

[0023] Figure 8 This is a diagram illustrating an exemplary format of the trigger frame to which the present disclosure can be applied.

[0024] Figure 9 This is a diagram illustrating an example format of an NFRP trigger frame.

[0025] Figure 10 The figure illustrates a UL preemption parameter set element according to an embodiment of the present disclosure.

[0026] Figure 11 The figure illustrates the user information field of a UL preemption trigger frame according to an embodiment of the present disclosure.

[0027] Figure 12 The illustration shows the format of a TB feedback NDP according to an embodiment of the present disclosure.

[0028] Figure 13 The illustration shows the operation of a station for an uplink preemption triggering method according to an embodiment of the present disclosure.

[0029] Figure 14 The diagram illustrates the operation of an access point for an uplink preemption triggering method according to an embodiment of the present disclosure. Detailed Implementation

[0030] In the following, embodiments according to the present disclosure will be described in detail with reference to the accompanying drawings. The detailed description disclosed with reference to the drawings is intended to describe exemplary embodiments of the present disclosure and not to represent the only embodiments in which the present disclosure may be practiced. The following detailed description includes specific details to provide a complete understanding of the present disclosure. However, those skilled in the art will recognize that the present disclosure may be practiced without these specific details.

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

[0032] In this disclosure, when an element is referred to as “connected,” “combined,” or “linked” to another element, it can include both indirect and direct connections where another element exists therebetween. Furthermore, in this disclosure, the terms “comprising” or “having” specify the presence of the mentioned features, steps, operations, components, and / or elements, but do not exclude the presence or addition of one or more other features, stages, operations, components, elements, and / or groups thereof.

[0033] In this invention, terms such as "first" and "second" are used only to distinguish one element from another and are not used to limit the elements. Unless otherwise stated, they do not limit the order or importance of the elements. Therefore, within the scope of this disclosure, a first element in one embodiment may be referred to as a second element in another embodiment, and similarly, a second element in one embodiment may be referred to as a first element in another embodiment.

[0034] The terminology used in this disclosure is for the purpose of describing particular embodiments and not for limiting 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” as used in this disclosure may refer to one of the associated enumerations, or is intended to refer to and include any and all possible combinations of two or more of them. Furthermore, unless otherwise stated, the “ / ” between words in this disclosure has the same meaning as “and / or”.

[0035] The examples disclosed herein can be applied to various wireless communication systems. For example, the examples disclosed herein can be applied to wireless LAN systems. For example, the examples disclosed herein can be applied to wireless LANs based on the IEEE 802.11a / g / n / ac / ax standards. Furthermore, the examples disclosed herein can be applied to wireless LANs based on the newly proposed IEEE 802.11be (or EHT) standard. The examples disclosed herein can be applied to wireless LANs based on the IEEE 802.11be version 2 standard, corresponding to the additional enhancements of the IEEE 802.11be version 1 standard. Additionally, the examples disclosed herein can be applied to next-generation standards-based wireless LANs following IEEE 802.11be. Furthermore, the examples disclosed herein can be applied to cellular wireless communication systems. For example, it can be applied to cellular wireless communication systems based on 3GPP standards using Long Term Evolution (LTE) technology and 5G New Radio (NR) technology.

[0036] The technical features that can be applied to examples of this disclosure will be described below.

[0037] Figure 1 The figure shows a block diagram of a wireless communication device according to an embodiment of the present disclosure.

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

[0039] Figure 1 The devices 100 and 200 shown in the diagram can be referred to as stations (STAs). For example, Figure 1 The devices 100 and 200 illustrated in the figure can be referred to by various terms such as transmitting device, receiving device, transmitting STA, and receiving STA. For example, STA 110 and 200 can perform an access point (AP) role or a non-AP role. That is, in this disclosure, STA 110 and 200 can perform AP and / or non-AP functions. When STA 110 and 200 perform AP functions, they can be simply referred to as AP, and when STA 110 and 200 perform non-AP functions, they can be simply referred to as STA. In addition, in this disclosure, AP can also be referred to as APSTA.

[0040] refer to Figure 1 The first device 100 and the second device 200 can transmit and receive radio signals via various wireless LAN technologies (e.g., the IEEE 802.11 series). The first device 100 and the second device 200 may include interfaces for the Media Access Control (MAC) layer and Physical Layer (PHY) conforming to the IEEE 802.11 standard.

[0041] Furthermore, the first device 100 and the second device 200 can additionally support various communication standards (e.g., 3GPP LTE series, 5G NR series standards, etc.) besides wireless LAN technology. Additionally, the devices disclosed herein can be implemented in various devices, such as mobile phones, vehicles, personal computers, augmented reality (AR) devices, virtual reality (VR) devices, etc. Furthermore, the STA of this specification can support various communication services, such as voice calls, video calls, data communication, autonomous driving, machine-type communication (MTC), machine-to-machine (M2M), device-to-device (D2D), IoT (Internet of Things), etc.

[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, proposals, methods, and / or operation flowcharts disclosed herein. For example, the processor 102 may transmit a wireless signal including the first information / signal via the transceiver 106 after generating first information / signal by processing information in the memory 104. Additionally, the processor 102 may receive a wireless signal including a second information / signal via the transceiver 106, and then store information obtained through signal processing of the second information / signal in the memory 104. The memory 104 may be connected to the processor 102 and may store various information relating 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 processes controlled by the processor 102 or for performing the descriptions, functions, processes, proposals, methods, and / or operation flowcharts disclosed herein. Here, processor 102 and memory 104 may be part of a communication modem / circuit / chip designed to implement wireless LAN technologies (e.g., LTE 802.11 series). Transceiver 106 may be connected to processor 102 and may transmit and / or receive wireless signals via one or more antennas 108. Transceiver 106 may include a transmitter and / or a receiver. Transceiver 106 may be used with an RF (radio frequency) unit. In this disclosure, "device" may refer to 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, proposals, methods, and / or operation flowcharts disclosed in this disclosure. For example, the processor 202 may generate third information / signals by processing information in the memory 204, and then transmit a wireless signal including the third information / signals via the transceiver 206. Additionally, the processor 202 may receive wireless signals including fourth information / signals via the transceiver 206, and then store information obtained through 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 code including instructions for performing all or part of the processes controlled by the processor 202 or for performing the descriptions, functions, processes, proposals, methods, and / or operation flowcharts disclosed in this disclosure. Here, processor 202 and memory 204 may be part of a communication modem / circuit / chip designed to implement wireless LAN technologies (e.g., IEEE 802.11 series). Transceiver 206 may be connected to processor 202 and may transmit and / or receive wireless signals via one or more antennas 208. Transceiver 206 may include a transmitter and / or a receiver. Transceiver 206 may be used with an RF unit. In this disclosure, "device" may refer to a communication modem / circuit / chip.

[0044] The hardware components of devices 100 and 200 will be described in more detail below. However, they are not limited thereto, but 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, processes, proposals, methods, and / or operation flowcharts disclosed in this disclosure. One or more processors 102 and 202 may generate messages, control information, data, or information according to the descriptions, functions, processes, proposals, methods, and / or operation flowcharts disclosed in this 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, processes, proposals, and / or methods disclosed in this disclosure to provide them to one or more transceivers 106 and 206. One or more processors 102, 202 may receive signals (e.g., baseband signals) from one or more transceivers 106, 206 and obtain PDUs, SDUs, messages, control information, data, or information in accordance with the descriptions, functions, processes, proposals, methods, and / or operation flowcharts disclosed in this disclosure.

[0045] One or more processors 102, 202 may be referred to as controllers, microcontrollers, microprocessors, or microcomputers. One or more processors 102, 202 may be implemented by hardware, firmware, software, or a combination thereof. In examples, one or more ASICs (Application-Specific Integrated Circuits), one or more DSPs (Digital Signal Processors), one or more DSPDs (Digital Signal Processing Devices), one or more PLDs (Programmable Logic Devices), or one or more FPGAs (Field-Programmable Gate Arrays) may be included in one or more processors 102, 202. The descriptions, functions, processes, proposals, methods, and / or operation flowcharts included in this disclosure may be implemented using firmware or software, and the firmware or software may be implemented to include modules, processes, functions, etc. Firmware or software configured to execute the descriptions, functions, processes, proposals, methods, and / or operation flowcharts included in this disclosure may be included in one or more processors 102, 202 or may be stored in one or more memories 104, 204 and driven by one or more processors 102, 202. The descriptions, functions, processes, proposals, methods, and / or operation flowcharts included in this invention may be implemented by firmware or software in the form of code, commands, and / or command sets.

[0046] One or more memories 104, 204 may be connected to one or more processors 102, 202 and are capable of storing 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 drive, registers, cache memory, computer-readable storage media, and / or combinations thereof. One or more memories 104, 204 may be located internally and / or externally to one or more processors 102, 202. Furthermore, one or more memories 104, 204 may be connected to one or more processors 102, 202 via various technologies such as wired or wireless connections.

[0047] One or more transceivers 106, 206 can transmit user data, control information, wireless signals / channels, etc., mentioned in the methods and / or operation flowcharts of this disclosure to one or more other devices. One or more transceivers 106, 206 can receive user data, control information, wireless signals / channels, etc., mentioned in the descriptions, functions, processes, proposals, methods, and / or operation flowcharts included in this disclosure from one or more other devices. For example, one or more transceivers 106, 206 can be connected to one or more processors 102, 202 and can transmit and receive wireless signals. For example, one or more processors 102, 202 can control one or more transceivers 106, 206 to transmit user data, control information, or wireless signals to one or more other devices. Furthermore, one or more processors 102, 202 can control one or more transceivers 106, 206 to receive user data, control information, or wireless signals from one or more other devices. Furthermore, 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 transmit and receive user data, control information, wireless signals / channels, etc., mentioned in the descriptions, functions, processes, proposals, methods, and / or operation flowcharts included in this disclosure, via one or more antennas 108, 208. In this invention, one or more antennas may be multiple physical antennas or multiple logical antennas (e.g., antenna ports). One or more transceivers 106, 206 may process the received wireless signals / channels, etc., by converting them from RF band signals to baseband signals 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 one or more processors 102, 202 from baseband signals to RF band signals. Therefore, one or more transceivers 106, 206 may include (analog) oscillators and / or filters.

[0048] For example, one of STA 100 and 200 can perform the expected operation of an AP, and the other of STA 100 and 200 can perform the expected operation of a non-AP STA. For example, Figure 1 Transceivers 106 and 206 can perform transmission and reception operations of signals (e.g., packet or physical layer protocol data units (PPDUs) conforming to IEEE 802.11a / b / g / n / ac / ax / be). Furthermore, in this disclosure, the operations of generating transmit / receive signals or performing data processing or calculations on transmit / receive signals in advance by various STAs can be performed by… Figure 1 Processors 102 and 202 perform the following operations: For example, examples of generating transmit / receive signals or performing data processing or calculations on transmit / receive signals in advance may include 1) determining / acquiring / configuring / calculating / decoding / encoding bit information of fields (signals (SIG), short training field (STF), long training field (LTF), data, etc.) included in the PPDU; 2) determining / configuring / acquiring time resources or frequency resources (e.g., subcarrier resources) for the fields (SIG, STF, LTF, data, etc.) included in the PPDU; 3) determining / configuring / acquiring specific sequences (e.g., preamble sequences, STF / LTF sequences, additional sequences applied to SIG) for the fields (SIG, STF, LTF, data, etc.) included in the PPDU action; 4) power control operations and / or power-saving operations applied to the STA; and 5) operations related to determining / acquiring / configuring / calculating / encoding the ACK signal. Additionally, in the following examples, various information used by various STAs to determine / acquire / configure / calculate / decode / encode transmitted and received signals (e.g., information related to fields / subfields / control fields / parameters / power, etc.) can be stored. Figure 1 In memory 104 and 204.

[0049] In the following text, downlink (DL) can refer to a link used for communication from an AP STA to a non-AP STA, and can be used to send and receive DL PPDUs / packets / signals. In DL communication, the transmitter can be part of an AP STA, and the receiver can be part of a non-AP STA. Uplink (UL) can refer to a link used for communication from a non-AP STA to an AP STA, and can be used to send and receive UL PPDUs / packets / signals. In UL communication, the transmitter can be part of a non-AP STA, and the receiver can be part of an AP STA.

[0050] Figure 2 This is a diagram illustrating an exemplary structure of a wireless LAN system to which this disclosure can be applied.

[0051] A wireless LAN system can be structured by multiple components. Wireless LANs that support STA mobility transparent to upper layers can be provided through the interaction of these components. The Basic Services Set (BSS) corresponds to the basic building blocks of a wireless LAN. Figure 2 An example is shown where there are two BSSs (BSS1 and BSS2) and two STAs are included as members of each BSS (STA1 and STA2 are included in BSS1, and STA3 and STA4 are included in BSS2). Figure 2 The ellipse representing the BSS can also be interpreted as representing the coverage area within the corresponding BSS where STAs maintain communication. This area can be called the Basic Service Area (BSA). When a STA moves out of the BSA, it cannot directly communicate with other STAs within the BSA.

[0052] If we do not consider Figure 2 The DS shown represents the most basic type of BSS in a wireless LAN, which is the Independent BSS (IBSS). For example, an IBSS can have a minimal form consisting of only two STAs. For instance, assuming other components are omitted, BSS1 consisting only of STA1 and STA2, or BSS2 consisting only of STA3 and STA4, can respectively correspond to representative examples of IBSS. This configuration is possible when STAs can communicate directly without an AP. Furthermore, in this type of wireless LAN, it is not pre-configured but can be configured when a LAN is needed, and this can be called a self-organizing network. Because 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 access to the Distributed System (DS) is not allowed, thus forming a self-contained network.

[0053] A STA's membership in the BSS can be dynamically changed by opening or closing the STA, entering or leaving a BSS zone, etc. To become a member of the BSS, an STA can join the BSS using a synchronization process. To access all services of the BSS infrastructure, an STA should be associated with the BSS. This association can be established dynamically and can include the use of Distributed System Services (DSS).

[0054] Direct STA-to-STA distance in a wireless LAN can be limited by PHY performance. In some cases, this distance limit may be sufficient, but in others, communication between STAs at greater distances may be required. Distributed systems (DS) can be configured to support extended coverage.

[0055] DS refers to the structure of BSS interconnection. Specifically, such as... Figure 2As shown, a BSS can exist as an extension of a network composed of multiple BSSs. A DS is a logical concept and can be specified by the characteristics of the Distributed System Medium (DSM). In this respect, the Wireless Medium (WM) and the DSM can be logically separated. Each logical medium is used for a different purpose and by different components. These media are not limited to being the same, nor are they limited to being different. Thus, the flexibility of wireless LAN architectures (DS architectures or other network architectures) can be interpreted as multiple media being logically different. That is, wireless LAN architectures can be implemented in various ways, and the corresponding wireless LAN architectures can be independently specified by the physical characteristics of each embodiment.

[0056] DS can support mobile devices by providing seamless integration of multiple BSSs and the logical services necessary for address addressing to the destination. Additionally, DS can further include a component called a portal, which acts as a bridge for connections between the wireless LAN and other networks, such as IEEE 802.X.

[0057] An AP enables access to a DS via WM for its associated non-AP STA, and also refers to an entity that also functions as a STA. Data movement between the BSS and DS can be performed through the AP. For example, Figure 2 STA2 and STA3, as shown, possess the functionality of STAs and provide the ability for associated non-AP STAs (STA1 and STA4) to access the DS. Furthermore, since all APs essentially correspond to STAs, all APs are addressable entities. The address used by an AP for communication on the WM is not necessarily the same as the address used by an AP for communication on the DSM. A BSS consisting of APs and one or more STAs can be referred to as 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 on an uncontrolled port and can be processed by an IEEE 802.1X port access entity. Alternatively, when the controlled port is authenticated, transmitted data (or frames) can be delivered to the DS.

[0059] In addition to the DS structure described above, an Extended Service Set (ESS) can be configured to provide broad coverage.

[0060] An ESS (Service Set Identity) refers to a network of arbitrary size and complexity consisting of DS (Service Controller) and BSS (Service Set Service). An ESS can correspond to a set of BSSs connected to a DS. However, an ESS does not include the DS. An ESS network is characterized by being treated as an IBSS (Independent Service Set Service) within the Logical Link Control (LLC) layer. STAs included in an ESS can communicate with each other, and mobile STAs can move from one BSS to another BSS (within the same ESS) that is transparent to the LLC. APs included in an ESS can have the same Service Set Identity (SSID). The SSID is distinct from the BSSID, which is the identifier of the BSS.

[0061] Wireless LAN systems do not assume anything about the relative physical location of BSSs, and all of the following forms are possible. BSSs can partially overlap, which is a common form used to provide continuous coverage. Additionally, BSSs may not have physical connections, and logically, there is no limit to the distance between BSSs. Furthermore, BSSs may be physically located in the same location, which can be used to provide redundancy. Additionally, one (or more) IBSS or ESS networks can physically exist in the same space as one (or more) ESS networks. This can be analogous to the form corresponding to ESS networks when self-organizing networks operate in locations where ESS networks exist, when physically overlapping wireless networks are configured by different organizations, or when two or more different access and security policies are required in the same location.

[0062] Figure 3 This is a diagram used to explain the link setup process to which this disclosure can be applied.

[0063] For a STA to establish a link to the network and send / receive data, the process first involves network discovery, authentication, association establishment, and, importantly, security authentication. This link establishment process can also be called the session initiation process or session setup process. Furthermore, the discovery, authentication, association, and security settings within the link establishment process can be collectively referred to as the association process.

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

[0065] Scanning schemes include active scanning and passive scanning. Figure 3An exemplary illustration depicts a network discovery operation including an active scanning process. In an active scan, the STA performing the scan sends probe request frames while moving channels to discover which APs are present in its vicinity and awaits a response. A responder sends a probe response frame to the STA that sent the probe request frame as a response to the probe request frame. Here, the responder could be the STA that last sent a beacon frame in the BSS of the scanned channel. In the BSS, the AP becomes the responder because it sends a beacon frame, and in the IBSS, STAs in the IBSS take turns sending beacon frames, so the responder is not constant. For example, an STA that sends a probe request frame on channel 1 and receives a probe response frame on channel 1 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 a scan in the same manner (i.e., sending / receiving probe requests / responses on channel 2).

[0066] Although Figure 3 Although not shown, scanning operations can be performed passively. In passive scanning, the STA performing the scan waits for beacon frames while moving through channels. Beacon frames are one of the management frames defined in IEEE 802.11, and are periodically sent to notify of the existence of a wireless network and allow the STA performing the scan to find and participate in the network. In a BSS, the AP uses beacon frames to periodically send them, and in an IBSS, STAs within the IBSS take turns sending beacon frames. When a STA performing the scan receives a beacon frame, it stores the BSS information included in the beacon frame and records the beacon frame information for each channel while moving to another channel. The STA receiving the beacon frame can store the BSS-related information included in the received beacon frame, move to the next channel, and perform the scan in the next channel in the same manner. Comparing active and passive scanning, active scanning has the advantages of lower latency and lower power consumption.

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

[0068] The authentication process includes the STA sending an authentication request frame to the AP, and in response, the AP sending an authentication response frame to the STA. The authentication frame used for the authentication request / response corresponds to the management frame.

[0069] The authentication frame includes the authentication algorithm number, authentication transaction sequence number, status code, challenge text, robust security network (RSN), and finite cycle group, etc. This corresponds to some examples of information that can be included in the authentication request / response frame, as well as additional information that can be replaced with other information or further included.

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

[0071] After successful STA authentication, the association process can be performed in step S330. The association process includes the STA sending an association request frame to the AP, and the AP sending an association response frame to the STA in response.

[0072] For example, an association request frame may include information related to various capabilities, beacon listening intervals, service set identifiers (SSIDs), supported rates, supported channels, RSNs, mobile domains, supported operation classes, service indication map broadcast requests (TIM broadcast requests), and interoperability capabilities. Similarly, an association response frame may include information related to various capabilities, status codes, association IDs (AIDs), supported rates, enhanced distributed channel access (EDCA) parameter sets, received channel power indicators (RCPIs), received signal-to-noise ratio indicators (RSNIs), mobile domains, timeout intervals (e.g., association recovery time), overlapping BSS scan parameters, TIM broadcast responses, and quality of service (QoS) maps. This corresponds to some examples of information that can be included in association request / response frames, and can be replaced with other information or further supplementary information.

[0073] After the STA successfully associates with the network, a security setup process can be performed in step S340. The security setup process in step S340 can be referred to as the authentication process via a Robust Secure Network Association (RSNA) request / response, and the authentication process in step S320 can be referred to as the first authentication process. The security setup process in step S340 can also be simply referred to as the authentication process.

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

[0075] Figure 4 This is a diagram used to explain the retreat process to which this disclosure can be applied.

[0076] In wireless LAN systems, the basic access mechanism for Media Access Control (MAC) is Carrier Sense Multiple Access with Collision Avoidance (CSMA / CA). CSMA / CA is also known as the Distributed Coordination Function (DCF) of IEEE 802.11 MAC, and essentially employs a "listen-before-speak" access mechanism. Under this type of access mechanism, the AP and / or STA can perform a sensed free channel assessment (CCA) of the wireless channel or medium within a predetermined time interval (e.g., the DCF inter-frame interval (DIFS)) before initiating transmission. As a result of the sensing, if it is determined that the medium is idle, frame transmission is initiated 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 initiate its own transmission, and a delay period (e.g., a random backoff period) can be set for medium intervention, and frame transmission can be attempted after waiting. By applying a random backoff period, collisions can be minimized because several STAs are expected to attempt frame transmission after waiting for different time periods.

[0077] In addition, the IEEE 802.11 MAC protocol provides Hybrid Coordination Function (HCF). HCF is based on DCF and Point Coordination Function (PCF). PCF is a polling-based synchronous access method, referring to a method in which all receiving APs and / or STAs periodically poll to receive data frames. Furthermore, HCF includes Enhanced Distributed Channel Access (EDCA) and HCF-Controlled Channel Access (HCCA). EDCA is a contention-based access method used by providers to deliver data frames to multiple users, while HCCA uses a polling mechanism to use a non-contention-based channel access method. Additionally, HCF includes a media access mechanism for improving the QoS (Quality of Service) of wireless LANs, and allows QoS data to be transmitted in both contention-based (CP) and contention-free (CFP) periods.

[0078] refer to Figure 4 This section describes the operation based on a random backoff period. When a occupied / busy medium becomes idle, several STAs may attempt to transmit data (or frames). As a method to minimize collisions, each STA can individually select a random backoff count and attempt transmission after waiting for the corresponding time slot. The random backoff count has a pseudo-random integer value and can be determined as one of the values ​​from 0 to CW. Here, CW is the contention window parameter value. The CW parameter is assigned an initial value of CWmin, but can take a value twice as large if a transmission failure occurs (e.g., when an ACK for a transmitted frame is not received). When the CW parameter value reaches CWmax, data transmission can be attempted while maintaining the CWmax value until data transmission is successful, and when data transmission is successful, the CWmin value is reset. The values ​​of CW, CWmin, and CWmax are preferably set to 2.n -1 (n = 0, 1, 2, ...).

[0079] When the random backoff process begins, the STA continuously monitors the medium while counting down the backoff time slot based on the determined backoff count value. When medium occupancy is detected, it stops counting down and waits; when the medium becomes free, it resumes the remaining countdown.

[0080] exist Figure 4 In the example, when the packet to be sent arrives at STA3's MAC, STA3 can send the frame immediately after confirming that the medium is free for as long as DIFS. The remaining STAs monitor and wait for the medium to be occupied / busy. Meanwhile, data to be sent may also occur in each of STA1, STA2, and STA5, and when the medium is detected as free, each STA waits for as long as DIFS, and then performs a countdown on the backoff slot based on a random backoff count value selected by each STA. It is assumed that STA2 selects the minimum backoff count value, and STA1 selects the maximum backoff count value. That is, the case where STA5's remaining backoff time is less than STA1's remaining backoff time when STA2 completes the backoff count and starts frame transmission is illustrated. STA1 and STA5 temporarily stop the countdown and wait, while STA2 occupies the medium. When STA2 finishes occupying the medium and the medium becomes free again, STA1 and STA5 wait for DIFS and resume the stopped backoff count. That is, after counting down the remaining backoff slots for the remaining backoff time, frame transmission can begin. Because STA5's remaining backoff time is less than STA1's, STA5 begins frame transmission. While STA2 occupies the medium, data to be transmitted may also appear in STA4. From STA4's perspective, when the medium becomes idle, STA4 can wait for DIFS, and then execute a countdown based on a random backoff count value selected by STA4 before starting frame transmission. Figure 4 The example illustrates a scenario where the remaining backoff time of STA5 coincides exactly with the random backoff count value of STA4. In this case, a collision may occur between STA4 and STA5. When a collision occurs, neither STA4 nor STA5 receives an ACK, thus data transmission fails. In this situation, STA4 and STA5 can double their CW value, choose a random backoff count value, and begin a countdown. STA1 waits while the medium is occupied due to the transmissions of STA4 and STA5, waits for DIFS when the medium becomes idle, and then begins frame transmission after the remaining backoff time has elapsed.

[0081] like Figure 4As shown in the examples, data frames are frames used to transmit data forwarded to higher layers, and can be sent after a backoff performed after the DIFS (Distributed Information Function) begins to elapse when the medium becomes idle. Additionally, management frames are frames used to exchange management information that is not forwarded to higher layers, and can be sent after a backoff performed after an IFS (Information Function Sequence) such as a DIFS or a Point Coordination Function IFS (PIFS). Subtypes of management frames include beacons, association requests / responses, reassociation requests / responses, probe requests / responses, authentication requests / responses, etc. Control frames are frames used to control access to the medium. Subtypes of control frames include request to send (RTS), allow to send (CTS), acknowledge (ACK), power-saving polling (PS-Poll), block ACK (BlockAck), block ACK request (BlockACKReq), empty data packet announcement (NDP announcement), and triggers, etc. If a control frame is not a response frame to a previous frame, it is sent after a backoff performed after the DIFS elapses; if it is a response frame to a previous frame, it is sent without a backoff performed after the short IFS (SIFS) elapses. The type and subtype of a frame can be identified by the type field and subtype field in the Frame Control (FC) field.

[0082] The Quality of Service (QoS) ST can perform a backoff following the Arbitration IFS (AIFS) of the Access Class (AC) to which the frame belongs, i.e., AIFS[i] (where i is a value determined by the AC), and then the frame can be sent. Here, the frames that can use AIFS[i] can be data frames, management frames, or control frames other than response frames.

[0083] Figure 5 This is a diagram used to explain the CSMA / CA-based frame transmission operation to which this disclosure can be applied.

[0084] As mentioned above, the CSMA / CA mechanism includes virtual carrier sensing in addition to physical carrier sensing, which is directly sensed by the STA. Virtual carrier sensing is designed to compensate for problems that may arise in media access, such as hidden node issues. For virtual carrier sensing, the STA's MAC can use a Network Allocation Vector (NAV). The NAV is a value that indicates to other STAs the remaining time until the media becomes available for use by the currently available or authorized STA. Therefore, a value set to NAV corresponds to a period of time during which the media is scheduled for use by the STA sending the frame, and a period during which the STA receiving the NAV value is prohibited from accessing the media. For example, the NAV can be configured based on the value of the "Duration" field in the MAC header of the frame.

[0085] exist Figure 5In the example, it is assumed that STA1 intends to send data to STA2, and STA3 is in a position that allows it to eavesdrop on some or all of the frames being sent and received between STA1 and STA2.

[0086] To reduce the likelihood of transmission conflicts between multiple STAs in CSMA / CA-based frame transmission operations, a mechanism using RTS / CTS frames can be applied. Figure 5 In the example, while STA1 is transmitting, as a result of STA3's carrier sensing, it can be determined that the medium is in an idle state. That is, STA1 can correspond to a hidden node of STA3. Alternatively, in Figure 5 In the example, it can be determined that the carrier sensing result medium of STA3 is idle while the transmission of STA2 is being performed. That is, STA2 can correspond to a hidden node of 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 for transmissions from STA1 or STA3, can not attempt to occupy the channel during data transmission and reception between STA1 and STA2.

[0087] Specifically, STA1 can determine whether a channel is in use through carrier sensing. Regarding physical carrier sensing, STA1 can determine the channel occupancy status based on the energy level or signal correlation detected in the channel. Furthermore, regarding virtual carrier sensing, STA1 can use a network allocation vector (NAV) timer to determine the channel occupancy status.

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

[0089] If STA3 cannot eavesdrop on CTS frames from STA2 but can eavesdrop on RTS frames from STA1, STA3 can use the duration information included in the RTS frame to set the NAV timer for subsequent consecutive frame transmission cycles (e.g., SIFS+CTS frame+SIFS+data frame+SIFS+ACK frame). Alternatively, if STA3 can eavesdrop on CTS frames from STA2, even though STA3 cannot eavesdrop on RTS frames from STA1, STA3 can use the duration information included in the CTS frame to set the NAV timer for subsequent consecutive frame transmission cycles (e.g., SIFS+data frame+SIFS+ACK frame). That is, if STA3 can eavesdrop on one or more RTS or CTS frames from 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 before the NAV timer expires.

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

[0091] Figure 6 This is a diagram used to explain an example of the frame structure that can be used in a WLAN system to which this disclosure can be applied.

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

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

[0094] A basic PPDU frame can include a Short Training Field (STF), a Long Training Field (LTF), a Signal (SIG) field, and a Data field. The most basic PPDU format (e.g., Figure 7 The non-HT (high throughput) fields shown may consist only of legacy STF (L-STF), legacy LTF (L-LTF), legacy SIG (L-SIG) fields, and a data field. Additionally, depending on the PPDU format type (e.g., HT mixed format PPDU, HT-greenfield format PPDU, VHT (very high throughput) PPDU, etc.), additional (or different types) 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.)) may be included between the L-SIG field and the data field.

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

[0096] The SIG field can include various information related to PPDU transmission and reception. For example, the L-SIG field consists of 24 bits and can include a 4-bit rate field, a 1-bit reserved bit, a 12-bit length field, a 1-bit parity field, and a 6-bit tail field. The RATE field can include information about the modulation and coding rate of the data. For example, the 12-bit length field can include information about the length or duration of the PPDU. For example, the value of the 12-bit length field can be determined based on the type of PPDU. For example, for non-HT, HT, VHT, or EHT PPDUs, the value of the length field can be determined to be a multiple of 3. For example, for HE PPDUs, the value of the length field can be determined to be 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 a PPDU TAIL bit, as well as padding bits if necessary. Some bits of the SERVICE field can be used for synchronization of the descrambler at the receiver. The PSDU corresponds to the MAC PDU defined in the MAC layer, and may include data generated / used in the upper layers. The PPDU TAIL bit can be used to return the encoder to a 0 state. Padding bits can be used to adjust the length of the data field in predetermined units.

[0098] MAC PDUs are defined according to various MAC frame formats, and a basic MAC frame consists of a MAC header, frame body, and frame check sequence (FCS). MAC frames can be composed of MAC PDUs and are transmitted / received through the PSDU in the data portion of the PPDU frame format.

[0099] The MAC header includes a frame control field, a duration / ID field, and an address field. The frame control field can include control information required for frame transmission / reception. The duration / ID field can be set to the time for transmitting the corresponding frame. For detailed information on the sequence control, QoS control, and HT control subfields of the MAC header, please refer to the IEEE 802.11 standard document.

[0100] The NDP (Narrow Data PPDU) format refers to a PPDU format that does not include the data field. In other words, NDP refers to a frame format that includes the PPDU preamble (i.e., L-STF, L-LTF, L-SIG fields and additional non-legacy SIG, non-legacy STF, and non-legacy LTF (if present)) but does not include the remaining portion (i.e., the data field) in the general PPDU frame format.

[0101] Figure 7 This is a diagram illustrating an example of a PPDU as defined in the IEEE 802.11 standard that can be applied to this disclosure.

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

[0103] In addition to the basic PPDU format, the HT PPDU format (IEEE 802.11n) also includes the HT-SIG, HT-STF and HT-LFT fields. Figure 7 The HT PPDU format shown in (b) can be called the HT-mixed format. Alternatively, an HT-greenfield format PPDU can be defined, which corresponds to a format consisting of HT-GF-STF, HT-LTF1, HT-SIG, one or more HT-LTFs and a data field, excluding L-STF, L-LTF and L-SIG (not shown).

[0104] Examples of VHT PPDU format (IEEE 802.11ac) include, in addition to the basic PPDU format, VHT SIG-A, VHT-STF, VHT-LTF, and VHT-SIG-B fields (such as...). Figure 7 (as shown in (c)).

[0105] Examples of HE PPDU format (IEEE 802.11ax) include, in addition to the basic PPDU format, repeated L-SIG (RL-SIG), HE-SIG-A, HE-SIG-B, HE-STF, HE-LTF(s), and packet extension (PE) fields (such as...). Figure 7 (as shown in (d)). Based on the detailed example of the HE PPDU format, some fields may be excluded or their lengths may vary. For example, the HE-SIG-B field is included in the HE PPDU format for multi-user (MU), while it is not included in the HE PPDU format for single-user (SU). Additionally, the HE trigger (TB) based PPDU format does not include HE-SIG-B, and the length of the HE-STF field may vary to 8µs. The extended range (HE ER) SU PPDU format does not include the HE-SIG-B field, and the length of the HE-SIG-A field may vary to 16µs. For example, RL-SIG can be configured to be the same as L-SIG. The receiving STA can determine whether the received PPDU is an HE PPDU or an EHT PPDU based on the presence of RL-SIG, which will be described later.

[0106] EHT PPDU format can include Figure 7 (e) EHT MU (Multi-user) and Figure 7 (f) EHT TB (trigger-based) PPDU. The EHT PPDU format is similar to the HE PPDU format in that it includes RL-SIG, followed by L-SIG, but may include U (generic)-SIG, EHT-SIG, EHT-STF and EHT-LTF following RL-SIG.

[0107] Figure 7 In (e), the EHT MU PPDU corresponds to a PPDU that carries one or more data (or PSDU) for one or more users. That is, the EHT MU PPDU can be used for both SU and MU transmissions. For example, the EHT MU PPDU can correspond to a PPDU used for one or more receiving STAs.

[0108] Compared to EHT MU PPDU, Figure 7In (f), the EHT-SIG is omitted from the EHT TB PPDU. A STA that receives a trigger (e.g., a trigger frame or trigger response schedule (TRS)) for UL MU transmission 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 legacy STAs can attempt demodulation and decoding, and can be mapped based on a determined subcarrier frequency interval (e.g., 312.5 kHz). These can be referred to as pre-EHT modulated fields. Next, the EHT-STF, EHT-LTF, Data, and PE fields can be encoded and modulated for demodulation and decoding by an STA that has successfully decoded a non-legacy SIG (e.g., U-SIG and / or EHT-SIG) and obtained the information contained in the fields, and can be mapped based on a determined subcarrier frequency interval (e.g., 78.125 kHz). These can be referred to as EHT modulated fields.

[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 free VHT modulation fields, and the VHT STF, VHT-LTF, VHT-SIG-B, and Data fields can be referred to as VHT modulation fields.

[0111] Figure 7 The U-SIG included in the EHT PPDU format can be configured based on, for example, two symbols (e.g., two consecutive OFDM symbols). Each symbol used for the U-SIG (e.g., an OFDM symbol) 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 preamble tones.

[0112] U-SIGs can be constructed in 20MHz units. For example, if an 80MHz PPDU is constructed, the U-SIGs may be repeated. That is, an 80MHz PPDU can include the same four U-SIGs. PPDUs with bandwidths exceeding 80MHz can include different U-SIGs.

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

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

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

[0116] For example, the version-independent bits of U-SIG may include a 3-bit Physical Layer Version Identifier (PHY Version Identifier), and this information can indicate the PHY version (e.g., EHT, UHR, etc.) of the transmitted / received PPDU. The version-independent bits of U-SIG may include a 1-bit UL / DL Flag field. The first value of the 1-bit UL / DL Flag field is related to UL communication, and the second value is related to DL communication. The version-independent bits of 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 U-SIG may include information that directly or indirectly indicates the type of PPDU (e.g., SUPPDU, MU PPDU, TB PPDU, etc.).

[0118] The information necessary for PPDU transmission and reception can be included in the U-SIG. For example, the U-SIG may further include information about the bandwidth, information about the MCS technique applied to the non-legacy SIG (e.g., EHT-SIG or UHR-SIG), information indicating whether a DCM (dual-carrier modulation) technique (e.g., a technique that achieves a frequency diversity-like effect by repeating the same signal on two subcarriers) is applied to the non-legacy SIG, information about the number of symbols used for the non-legacy SIG, and may also include information about whether the non-legacy SIG is generated across the entire band, etc.

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

[0120] A preamble can refer to the transmission of a PPDU in which no signal is present in one or more frequency units within the bandwidth of the PPDU. For example, the size of the frequency unit (or the resolution of the preamble) can be defined as 20MHz, 40MHz, etc. For example, a preamble can be applied to a PPDU of a predetermined size or larger bandwidth.

[0121] exist Figure 7 In the examples, non-legacy SIGs such as HE-SIG-B and EHT-SIG can include control information for receiving STAs. Non-legacy SIGs can be transmitted on at least one symbol, and a symbol can have a length of 4 µs. Information regarding the number of symbols used for EHT-SIGs can be included in previous SIGs (e.g., HE-SIG-A, U-SIG, etc.).

[0122] Non-legacy SIGs such as HE-SIG-B and EHT-SIG can include public fields and user-specific fields. Public fields and user-specific fields can be encoded separately.

[0123] In some cases, the common field can be omitted. For example, in compressed mode using non-OFDMA (Orthogonal Frequency Multiple Access), the common field can be omitted, and multiple STAs can receive PPDUs (e.g., the data field of the PPDU) through the same frequency band. In uncompressed mode using OFDMA, multiple users can receive PPDUs (e.g., the data field of the PPDU) through different frequency bands.

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

[0125] The common fields may include CRC bits and tail bits, where 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 fields may include RU allocation information. RU allocation information may include information about the locations of RUs assigned to multiple users (i.e., multiple receiving STAs).

[0126] An RU can include multiple subcarriers (or tones). RUs can be used when transmitting signals to multiple STAs based on OFDMA technology. Additionally, RUs can be defined even when transmitting signals to a single STA. Resources can be allocated in units of RUs for non-legacy STFs, non-legacy LTFs, and data fields.

[0127] The appropriate RU size can be defined based on the PPDU bandwidth. For the applied PPDU format (e.g., HE PPDU, EHT PPDU, UHR PPDU, etc.), the RUs can be defined the same or different. For example, in the case of an 80MHz PPDU, the RU placement for HEPPDU and EHT PPDU may differ. The applicable RU size, number and location, DC (direct current) subcarrier location and number, empty subcarrier location and number, guard subcarrier location and number, etc., for each PPDU bandwidth can be referred to as the tone scheme. For example, a tone scheme for high bandwidth can be defined as multiple iterations of a low bandwidth tone scheme.

[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. MRUs (multiple RUs) are distinguished from multiple individual RUs and correspond to a group of subcarriers composed of multiple RUs. For example, an MRU can be defined as 52+26-tone, 106+26-tone, 484+242-tone, 996+484-tone, 996+484+242-tone, 2×996+484-tone, 3×996-tone, or 3×996+484-tone. Furthermore, the multiple RUs constituting an MRU can be continuous or non-contiguous in the frequency domain.

[0129] The specific size of the RU can be reduced or increased. Therefore, the specific size of each RU (i.e., the number of corresponding tones) in this disclosure is not limiting or illustrative. In addition, in this disclosure, the number of RUs can vary depending on the RU size within a predetermined bandwidth (e.g., 20, 40, 80, 160, 320 MHz, ...).

[0130] Figure 7 The names of each field in the PPDU format are exemplary, and the scope of this disclosure is not limited to the names. Furthermore, the examples of this disclosure can be applied to... Figure 7 The PPDU format illustrated in the figure, and its application in... Figure 7 The PPDU format excludes some fields and / or adds some fields to the new PPDU format.

[0131] Trigger Frame

[0132] Figure 8 The diagram illustrates an exemplary format of the trigger frame that can be applied to this disclosure.

[0133] A trigger frame can allocate resources for one or more TB PPDU transmissions and request TB PPDU transmissions. The trigger frame may also include additional information required by the STA in response to sending the TB PPDU. The trigger frame may include a public information field and a user information list field in the frame body.

[0134] The public information field may include information typically applied to the transmission of one or more TB PPDUs requested by the trigger frame, such as trigger type, UL length, whether there are subsequent trigger frames (e.g., more TFs), whether CS (channel sensing) is required, UL BW (bandwidth), etc.

[0135] 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 Polling (BFRP), Multi-User Block Acknowledgment Request (MU-BAR), Multi-User Request Transmission (MU-RTS), Buffer Status Report Polling (BSRP), Multicast with Retry (GCR) MU-BAR, Bandwidth Query Report Polling (BQRP), and NDP Feedback Report Polling (NFRP), respectively, and values ​​8 to 15 are defined as reserved.

[0136] Within public information, the trigger-related public information subfields can include information selectively included based on the trigger type.

[0137] Special user information fields can be included within the trigger frame. These special user information fields do not include user-specific information, but rather include extended public information not provided in the public information fields.

[0138] The user information list includes zero or more user information fields. Figure 8 An example illustration shows the EHT variant user information field format.

[0139] The AID12 subfield primarily indicates that it is a user information field for a STA with the corresponding AID. Additionally, if the AID12 field has a predetermined specific value, it can be used for other purposes, such as assigning a Random Access (RA)-RU, or configuring it as a specific user information field. A specific user information field is a user information field that does not include user-specific information but includes extended public information not provided in the public information field. For example, a specific user information field can be identified by an AID12 value of 2007, and the specific user information field flag subfield in the public information field can indicate whether a specific user information field is included.

[0140] The RU allocation subfield indicates the size and location of the RU / MRU. Therefore, the RU allocation subfield can be interpreted together with the PS160 (primary / secondary 160MHz) subfield of the user information field, the UL BW subfield of the public information field, and so on.

[0141] Figure 9 This is a diagram illustrating an exemplary format of an NFRP trigger frame.

[0142] Instead of channel probing, the AP uses a Non-Packet Feedback Reporting (NDP) procedure to collect feedback from multiple non-AP STAs. To do this, the AP sends an NDP Feedback Report Pool (NFRP) trigger frame to request NDP feedback reporting responses from numerous non-AP STAs identified by the scheduling AID range in the trigger frame. NDP feedback reporting responses from non-AP STAs are TB Feedback NDPs. Non-AP STAs use the information sent in the NFRP trigger frame to determine if they are scheduled, and if so, derive the parameters used to send their responses.

[0143] In the case of an NFRP triggered frame, the UL BW subfield within the Common Information field indicates the bandwidth of the NDP feedback report response.

[0144] In addition, in the case of an NFRP triggered frame, one or more subfields within the common information field (e.g., the Space-Time Block Coding (STBC) subfield, the UL spatial reuse subfield, the pre-FEC (Forward Error Correction) padding factor subfield, the PE (Packet Extension) disambiguation subfield, etc.) can be retained.

[0145] Scheduled non-AP STAs are identified by the range of AIDs. The Start AID subfield defines the first AID of the AID range scheduled in response to an NFRP trigger frame.

[0146] A value of 0 in the feedback type subfield indicates a resource request, and all other values ​​are reserved.

[0147] The Uplink Target Received Power (UL Target Received Power) subfield indicates the expected received signal power measured at the AP's antenna connector and is averaged across the antenna for the non-legacy portion of the triggered (TB) PPDU transmitted from the assigned RU.

[0148] The Spatial Multiplexing User Count subfield indicates the number of STAs multiplexed for the same tone set within the same RU, and is encoded as the number of STAs minus 1.

[0149] Preemptive data transmission

[0150] In wireless LAN systems, preemption refers to the method by which an AP or STA transmits specific UL data faster without waiting to acquire its TXOP, or transmits designated data faster than other UL data within its own TXOP. In other words, preemption can be applied to data transmission by a STA that has not yet acquired its TXOP.

[0151] For example, specific data transmitted based on preemption might be packets / services requiring low latency (LL). LL services are unpredictable, have relatively small sizes, and must be transmitted quickly. However, in existing wireless LAN systems, during the TXOP period when a STA acquires the TXOP, other STAs must wait until that TXOP ends before attempting media access. Therefore, preemption techniques can be applied to support STAs that do not hold the TXOP for transmitting LL services during the TXOP period. However, the application of preemption-based data transmission is not limited to LL services and can also be applied to services for other purposes.

[0152] This disclosure presents a method for a STA other than the TXOP holder to attempt UL preemption within a DL (downlink) TXOP. The following method can be considered as an example of the UL preemption process.

[0153] After the TXOP holder's DL PPDU transmission is completed and a specific time has elapsed (e.g., xIFS, SIFS, PIFS), the STA attempting to preempt can send a preemption request packet (PPDU). Upon receiving the preemption request, the TXOP holder can send a UL preemption trigger to allow UL preemption. As another example, the TXOP holder can send a UL preemption trigger without a separate preemption request. The UL preemption trigger can be sent alone or together with other DL PPDUs. For example, the UL preemption trigger can be sent alone as a non-HT DUP (replica) PPDU or a DL MU PPDU, or it can be sent together with other DL PPDUs as a DL MU PPDU.

[0154] In the following, this disclosure presents the transmission of UL preemption triggering and subsequent processes (hereinafter referred to as "UL preemption process" or "UL preemption triggering process").

[0155] From the perspective of the AP as the TXOP holder, the UL preemption process can be as follows.

[0156] Step 1) The AP can send a UL preemption trigger frame to allow UL preemption. For example, a Non-Packet Feedback Report Pool (NFRP) trigger frame can be used as a UL preemption trigger frame. A detailed description of the content and format of the UL preemption trigger frame will be provided later.

[0157] Step 2) Following xIFS (e.g., SIFS), the AP can receive UL preemption messages / requests. As an example of a UL preemption message / request, a Triggered-Based (TB) Feedback NDP can be used. A detailed description of the format and content of UL preemption messages / requests (e.g., TB Feedback NDPs) will be provided later.

[0158] Step 3) Then, after xIFS (e.g., SIFS), or at a timing arbitrarily determined by the AP, the AP may send a trigger frame based on the information of the UL preemption message / request received in step 2, for (triggering) the transmission of UL preemption data of the STA.

[0159] Step 4) Then, after xIFS (e.g., SIFS), the AP can receive one or more UL TB PPDUs from one or more STAs. If there are requests for more resources from one or more STAs (e.g., the transmission of a UL TB PPDU includes a request for more resources), the AP can repeat the process of steps 3 and 4.

[0160] - From the perspective of the STA associated with the AP as the TXOP holder, the UL preemption process is as follows.

[0161] Step 1) The STA receives the UL preemption trigger frame, and the STA intending to attempt UL preemption can prepare to send a UL preemption message / request (e.g., TB feedback NDP) according to the instructions in the UL preemption trigger frame. A detailed description of the content and format of the UL preemption trigger frame is provided below.

[0162] Step 2) Furthermore, following xIFS (e.g., SIFS), among the STAs indicated / identified by the UL preemption trigger frame, the STA intending to attempt UL preemption can send a UL preemption message / request from the specified resource. An example of a UL preemption message / request could be a TB Feedback NDP. A detailed description of the format and content of a UL preemption message / request (e.g., a TB Feedback NDP) is provided below.

[0163] Step 3) Then, after xIFS (e.g., SIFS), or at a timing arbitrarily determined by the AP, the STA that sent the UL preemption message / request of Step 2 receives a trigger frame from the AP for (triggering) the transmission of UL preemption data, and determines whether they can send UL preemption data.

[0164] Step 4) Then, following the xIFS (e.g., SIFS), one or more STAs, indicated / identified by the trigger frame of Step 3, construct a UL preemption PPDU including the UL preemption data and send the UL preemption PPDU to the AP as indicated by the trigger frame of Step 3. Here, if the UL preemption PPDU configured for a specified resource is insufficient to carry all the UL preemption data, the STA can send a request for more resources (e.g., include a request for more resources when sending the UL preemption PPDU). In this case, the process of Steps 3 and 4 can be repeated.

[0165] Example 1: Format and content of UL preemption trigger frame

[0166] This disclosure presents a method for using an NFRP trigger frame for UL preemption triggering. In this disclosure, the NFRP trigger frame for UL preemption triggering is referred to as a UL preemption trigger frame to distinguish it from a general NFRP trigger frame.

[0167] Unless otherwise stated in this disclosure, the UL preemption trigger frame may retain the format of the NFRP trigger frame described above (see...). Figure 9 ).

[0168] In order to use an NFRP trigger frame for UL preemption triggering, it is necessary to indicate that the trigger frame is an NFRP trigger frame for UL preemption, which is different from existing NFRP trigger frames (i.e., indicating that the NFRP trigger frame is a UL preemption trigger frame). That is, there is the above indication, and in the indicated AID, only the STA that sends UL preemption data will respond.

[0169] Here, as an example of an indication method, one of the reserved bits in the public information field of a UL preemption trigger frame can be used to indicate whether an NFRP trigger frame is a UL preemption trigger frame. In other words, a 1-bit UL preemption indication subfield can be defined in the public information field to indicate whether an NFRP trigger frame is a UL preemption trigger frame. For example, if the subfield is "0" (or "1"), it indicates an existing NFRP trigger frame, and conversely, if it is "1" (or "0"), it indicates that the NFRP trigger frame (i.e., a UL preemption trigger frame) is a UL preemption-related message.

[0170] As another example of the method of indication, the feedback type subfield in the user information field of the NFRP trigger frame can be used. That is, as mentioned above, since the feedback type is currently specified as 0 for the resource request, other values ​​can be specified for UL preemption (e.g., feedback type = 1).

[0171] The following is an example of a method to provide the STA's AID to send a UL preemption message / request request.

[0172] Similar to existing methods, based on bandwidth, UL preemption messages / requests for N STAs can be triggered from the initial AID (i.e., the first AID in the AID range). For example, 18 AIDs can be specified for 20 MHz, and similarly, based on bandwidth, it is possible to extend this to 36 AIDs for 40 MHz, 72 AIDs for 80 MHz, and so on.

[0173] In this case, the RU tone set index (RU_TONE_SET_INDEX) can be mapped to each AID, as shown in Table 1 below.

[0174] Table 1 illustrates an example of (UHR or HE)-LTF subcarrier mapping for (UHR or HE)TB feedback NDP at a 20 MHz bandwidth.

[0175] Table 1

[0176] In Table 1, FEEDBACK_STATUS=0 means that the amount of buffered data in the STA does not exceed the resource request buffer threshold. Conversely, FEEDBACK_STATUS=1 means that the amount of buffered data in the STA exceeds the resource request buffer threshold.

[0177] Referring to Table 1, the STA checks whether its AID is included in the AID range indicated by the start AID subfield in the user field within the UL preemption trigger frame. If its AID is included in that range, it uses the LTF tone index determined by the amount of buffered data in the tone used indicated by RU_TONE_SET_INDEX corresponding to its AID (e.g., {-113, -77, -41, 6, 42, 78} or {-112, -76, -40, 7, 43, 79} if RU_TONE_SET_INDEX=1 is mapped to the AID) to send the TB feedback NDP (i.e., UL preemption message / request) (i.e., power supply to the determined LTF tone).

[0178] Here, the UL preemption process can be used to quickly transfer specific UL data within a TXOP that has not yet been acquired, and the resource request buffer threshold can be defined separately from the existing NDP feedback report parameter set. For example, as Figure 10 As shown, it can be defined separately for low-latency services.

[0179] Figure 10 The UL preemption parameter set elements according to embodiments of this disclosure are shown.

[0180] refer to Figure 10 The UL preemption (or low latency) parameter set can be configured to include subfields for element ID, length, element ID extension, and resource request buffer threshold index.

[0181] Here, the element ID and element ID extension can indicate that the element is a UL preemptive (or low-latency) parameter set element. The length subfield can indicate the number of octets in the element, excluding the element ID and length subfield.

[0182] The resource request buffer threshold index subfield can be used to calculate the buffer threshold for resource requests in TB feedback NDP (i.e., UL preemption messages / requests). For example, the resource request buffer threshold could be 2. （资源请求缓冲阈值指数） Eight bits.

[0183] This UL preemption (or low latency) parameter set can be sent in beacon frames or probe response frames, etc.

[0184] Alternatively, the UL preemption trigger frame can indicate 36 AIDs at a 20 MHz bandwidth. In this case, it can be similarly extended to other bandwidths, such as 72 AIDs at a 40 MHz bandwidth and 144 AIDs at an 80 MHz bandwidth. Unlike the method of indicating 18 AIDs at a 20 MHz bandwidth, both '0' and '1' of FEEDBACK_STATUS can be configured as AID indications. That is, in this case, different UL preemption messages / requests cannot be sent based on the resource request buffer threshold.

[0185] In this case, the (UHR or HE)-LTF subcarrier mapping can be shown in Table 2 below.

[0186] Table 2 illustrates the (HUR or HE)-LTF subcarrier mapping for (UHR or HE)TB feedback NDP at 20 MHz.

[0187] Table 2

[0188] Referring to Table 2, the STA checks whether its AID is included in the AID range indicated by the starting AID subfield in the user field within the UL preemption trigger frame. If its AID is included in that range, it sends the TB feedback NDP (i.e., UL preemption message / request) (i.e., power supply for the determined LTF tone) using the LTF tone index indicated by the RU_TONE_SET_INDEX corresponding to its AID (e.g., {-113, -77, -41, 6, 42, 78} when RU_TONE_SET_INDEX=1 is mapped to the AID).

[0189] In this method, it is not necessary to... Figure 10 Define a separate set of UL preemption (or low latency) parameters, as in the example.

[0190] As another method for configuring AIDs, the UL preemption trigger frame can indicate AID groups, and thus also non-contiguous AIDs. Group identifiers (IDs) 1 to M can be pre-configured, and P AIDs can be mapped to each group ID (where P is an integer greater than 0). For example, UL preemption group ID set elements can be defined so that the AP can notify the STA in advance (e.g., via a beacon frame or probe response frame).

[0191] In this case, the group ID index can be indicated in the starting AID subfield within the user information field of the UL preemption trigger frame.

[0192] Alternatively, the AID p (1 ≤ p ≤ P) among the P AIDs included in the group ID index m (1 ≤ m ≤ M) can be indicated in the starting AID subfield of the user information field in the UL preemption trigger frame. In this case, the index of the group ID can be directly indicated when the new group ID index subfield is defined, or the number of groups in the group ID index m can be indicated when the new group number subfield is defined.

[0193] As an alternative method for configuring AIDs, multiple user information fields can be configured within the NFRP trigger frame for UL preemption (i.e., UL preemption trigger frame). In other words, user information fields can be included for each AID, just as in the basic trigger frame.

[0194] Figure 11 The user information field of a UL preemption trigger frame according to an embodiment of the present disclosure is shown.

[0195] Figure 11 This is an example of a user information field in a UL preemption trigger frame, but this disclosure is not limited thereto, and the number of bits required for each subfield can be defined differently.

[0196] Reference Figure 11 (a) Just like the basic trigger frame, each AID in the UL preemption trigger frame can include a user information field.

[0197] Each user information field in the UL preemption trigger frame can be configured to include one or more of the following: AID subfield, RU_TONE_SET_INDEX subfield, reserved bit, feedback type subfield, UL target received power subfield, and number of spatially multiplexed users subfield.

[0198] Here, unlike existing NFRP trigger frames, the AID subfield indicates one AID for each user information field, thus allowing requests for NFRs based on a single AID.

[0199] The RU_TONE_SET_INDEX subfield can indicate the RU_TONE_SET_INDEX sent by the corresponding AID. This subfield can be omitted, in which case the STA can derive its own RU_TONE_SET_INDEX by calculating the cumulative number of previous user fields.

[0200] Reference Figure 11 (b) can indicate the starting AID and the number of consecutive AIDs for each user information field.

[0201] Each user information field in the UL preemption trigger frame can be configured to include one or more of the following: start AID subfield, AID quantity subfield, reserved bits, feedback type subfield, start RU_TONE_SET_INDEX subfield, UL target received power subfield, and spatial multiplexing user quantity subfield.

[0202] In this scenario, a range of AIDs can be indicated for each user field, and the start AID subfield can indicate the first AID within the range of AIDs indicated by a single user field. If the number of AID subfields (e.g., 5 to 8 bits) is "0", NFR can be requested by indicating the number of consecutive AIDs from the start AID until the end of the bandwidth (the number of remaining RU_TONE_SET_INDEX), and if the value is "1" or greater, NFR can be requested by indicating the number of consecutive AIDs.

[0203] The starting RU_TONE_SET_INDEX subfield (e.g., 5 to 8 bits) indicates the RU_TONE_SET_INDEX to be sent by the STA using the starting AID included in the corresponding user information field. For example, if the starting AID = 2000, the number of AIDs = 3, and the starting RU_TONE_SET_INDEX = 10, then the STA with AID 2000 can send the NFR to RU_TONE_SET_INDEX = 1, the STA with AID 2001 can send the NFR to RU_TONE_SET_INDEX = 11, and the STA with AID 2002 can send the NFR to RU_TONE_SET_INDEX = 12. Alternatively, this field can be omitted, in which case the STA can derive its own RU_TONE_SET_INDEX by calculating the cumulative number of AIDs from the previous user information field.

[0204] Reference Figure 11 (c) The group ID method described above can be applied to each user information field.

[0205] Each user information field in the UL preemption trigger frame can be configured to include one or more of the following: group ID subfield, AID bitmap subfield, feedback type subfield, start RU_TONE_SET_INDEX subfield, UL target received power subfield, and number of spatially multiplexed users subfield.

[0206] As mentioned above, group IDs 1 to M (including P AIDs for each group) can be pre-configured, and the group ID subfield can indicate a single group ID.

[0207] If the group ID includes AIDs 1 to P, then the bit P can be used to indicate the AID bitmap subfield in bitmap format so that only some AIDs included in the group ID are indicated, and NFRs are requested only from some STAs. This subfield can be omitted, in which case NFRs are requested sequentially from all AIDs since all AIDs included in the group ID are indicated.

[0208] The starting RU_TONE_SET_INDEX subfield indicates the RU_TONE_SET_INDEX to be sent by the STA with the first AID included in the corresponding user information field. This subfield can be omitted, in which case the STA can derive its own RU_TONE_SET_INDEX by calculating the cumulative number of AIDs in the previous user information fields.

[0209] Example 2: Format of TB Feedback NDP

[0210] Figure 12 The format of a TB feedback NDP according to an embodiment of the present disclosure is shown.

[0211] Figure 12 (a) illustrates the conventional HE TB Feedback NDP format. That is, a STA attempting to perform UL preemption (with UL preemption data) can send a conventional HE TB Feedback NDP in response to a UL preemption trigger frame.

[0212] Figure 12 (b) illustrates the newly defined UHR TB Feedback NDP format. The UHR TB Feedback NDP may include L-STF, L-LTF, L-SIG, RL-SIG, UHR-STF, and UHR-LTF. The UHR TB Feedback NDP may include a U-SIG (which may follow the EHT configuration, or have a SIG field with a different name performing the same role as the U-SIG, or a newly defined generic / common SIG field in the UHR), and may be a UHR SU or MUPPDU that does not perform the same role as the EHT-SIG, as well as a data portion. The RU tone assignment in the LTF used for the UHR may remain the same as before.

[0213] In other words, a STA attempting to preempt UL (with UL preempt data) can send a newly defined UHR TB feedback NDP in response to a UL preempt trigger frame.

[0214] STA can send TB feedback NDP (e.g., according to the AID indicated in the UL preemption trigger frame) by adding power to the used tone. Figure 12After receiving the TB feedback NDP, the AP can determine whether to execute a UL preemption request based on each AID by detecting the power of each used tone.

[0215] Example 3: Method for sending TB feedback NDP based on UL preemption classification

[0216] This invention proposes a method for using NFRP trigger frames for UL preemption triggering, and this embodiment proposes a method for classifying and triggering UL preemption based on UL preemption data.

[0217] The AP can configure classification criteria for UL preemption data and trigger UL preemption data that meets the classification criteria only. The STA can send a UL preemption message / request only when there is UL preemption data that meets the classification criteria.

[0218] As an example of a classification criterion, a Service Identifier (TID) can be configured as a classification criterion and can be defined to include a TID subfield within the UL preemption trigger frame. In this case, only STAs with UL preemption data that belong to the TID indicated by the TID subfield (i.e., buffered) can send a TB feedback NDP.

[0219] As another example, the delay limit can be configured as a classification criterion, and can be defined as a delay limit subfield that includes the UL preemption trigger frame. In this case, only STAs with UL preemption data less than or equal to the delay limit value indicated by the delay limit subfield (i.e., buffered) can send TB feedback NDP.

[0220] As another example, the required latency value can be configured as a classification criterion. In this case, the required latency value can be predefined (e.g., specified in the criterion) or configured by the AP. In this case, only STAs with (i.e., buffered) UL preemptive data that have a latency less than or equal to a specific predefined (or configured) value (e.g., 1ms) can send TB feedback NDP.

[0221] Furthermore, the buffer size, queue size, or resource request buffer threshold used for the aforementioned UL preemptive data can be configured as a classification criterion, and in this case, only STAs with UL preemptive data that meet the classification criteria (i.e., buffered) can send TB feedback NDP.

[0222] Furthermore, the flag bit can be configured to indicate whether triggering is performed according to the classification criteria described above. For example, if the flag = '0', STAs included in the AID identified by the UL preemption trigger frame among STAs with UL preemption data can send a TB feedback NDP (i.e., a UL preemption message / request) even without a classification criterion (even if the classification criterion is set). On the other hand, if the flag = "1", STAs included in the AID identified by the UL preemption trigger frame among STAs with UL preemption data can send a TB feedback NDP (i.e., a UL preemption message / request) only if the classification criteria described above are met. Alternatively, "All UL Preemption" can be configured as an option for each classification criterion value (TID, delay limit, required delay, etc.), and when "All UL Preemption" is indicated, STAs with UL preemption data without a classification criterion and included in the AID identified by the UL preemption trigger frame can send a TB feedback NDP.

[0223] In another approach, a single STA can send one or more TB feedback NDPs for UL preemption data belonging to various categories. That is, the AP can trigger the sending of individual TB feedback NDPs based on the category of the UL preemption data, and the STA can send a TB feedback NDP for each UL preemption data for each category.

[0224] For example, using the existing FEEDBACK_STATUS can trigger UL preemption for two categories.

[0225] Table 3 illustrates the (UHR or HE)-LTF subcarrier mapping for (UHR or HE) TB feedback NDP at 20MHz.

[0226] Table 3

[0227] For example, referring to Table 3, if the required latency is less than or equal to a specific value (e.g., 1 millisecond), the STA can use the RU_tone index with FEEDBACK_STATUS='0' to configure the LTF field and send a TB feedback NDP. On the other hand, if the required latency is greater than or equal to a specific value (e.g., 1 millisecond), the STA can use the RU_tone index with FEEDBACK_STATUS='1' to configure the LTF field and send a TB feedback NDP.

[0228] Here, the required latency can be replaced by the latency limits, queue size, or buffer size mentioned above, and the classification criteria can also be configured to be two or more.

[0229] When the AP receives the TB feedback NDP, it performs power detection for each tone used in order to determine not only whether a UL preemption message / request is sent per AID, but also to determine information about the classification of UL preemption data.

[0230] As another example, if there are three categories, the UL preemption trigger for the three categories might be as follows.

[0231] Table 4 illustrates the (UHR or HE)-LTF subcarrier mapping for (UHR or HE)TB feedback NDP at a 20 MHz bandwidth.

[0232] Table 4

[0233] Referring to Table 4, categories can be configured as follows: Category 1 (required latency less than or equal to a specific value 1 (e.g., 1ms)), Category 2 (required latency less than or equal to a specific value 2 (e.g., 5ms)), and Category 3 (required latency less than or greater than a specific value 3 (e.g., 10ms)). In this case, the STA can consider which category the latency required for its UL preemption data belongs to, configure the LTF field using the RU_tone index corresponding to that category, and send the TB feedback NDP.

[0234] Upon receiving the TB feedback NDP, the AP performs power detection for each tone used in order to determine not only whether a UL preemption message / request has been sent for each AID, but also to determine information about the classification of the UL preemption data.

[0235] This allows for the expansion to four or more categories. However, as the number of categories increases, the number of AIDs that can be assigned may decrease.

[0236] As another example, orthogonal codes can be applied when the tone is sent according to the following classifications. In this case, there is an advantage that the number of AIDs that can be assigned does not decrease even as the number of classifications increases.

[0237] Table 5 illustrates the (UHR or HE)-LTF subcarrier mapping at 20 MHz for (UHR or HE) TB feedback NDP.

[0238] Table 5

[0239] Referring to Table 5, since there are 6 used tones, up to 6 orthogonal codes can be applied, and therefore up to 6 categories can be configured. Alternatively, as shown in Table 5, only 4 orthogonal codes can be applied, and up to 4 categories can be configured. In this case, the orthogonal codes can be applied to only 4 of the 6 used tones. For example, assuming that the orthogonal codes are not applied to the 2nd and 5th tones, and that power P is applied to the used tones, then signals according to category 1 ([PPPPPP]), category 2 ([PPP -PP -P]), category 3 ([PP -PP PP]), and category 4 ([PP –P -PPP]) can be mapped to each used tone. In the same way, other numbers of categories can also be applied, up to 6. The STA can send TB feedback NDP (i.e., UL preemption message / request) according to one or more of categories 1 to 4, based on the category of the UL preemption data it intends to send. Upon receiving the TB feedback NDP, the AP applies an orthogonal code to each tone used and performs power detection to determine not only whether a UL preemption message / request is sent per AID, but also to determine information about the classification of UL preemption data.

[0240] The trigger frame mentioned above in this disclosure can be a non-HT DUP (replicated) PPDU format. A non-HT DUP PPDU means that it is replicated every 20 MHz and includes the same legacy PPDU. Here, legacy PPDU means that it is... Figure 7 The configuration includes legacy components (L-STF, L-LTF, and L-SIG), but does not include the SIG, STF, or LTF components.

[0241] Alternatively, the trigger frame mentioned above in this disclosure may be in EHT MU PPDU format or UHR MU PPDU format. UHR MU PPDU may include some format features of EHT MU PPDU (see...). Figure 7 ).

[0242] Figure 13 The operation of a station for an uplink preemption triggering method according to an embodiment of the present disclosure is illustrated.

[0243] Figure 13 The operation of the STA device based on the previously proposed method is shown. Figure 13 The examples in this document are for illustrative purposes only and are not intended to limit the scope of this disclosure. They may be omitted depending on the circumstances and / or configuration. Figure 13 Some of the steps shown.

[0244] Reference Figure 13 The STA device receives a UL preemption trigger frame from the AP device to allow UL preemption (S1301).

[0245] Here, as mentioned above, preemption can refer to the method of sending specific UL data earlier without waiting for the AP or STA to obtain its TXOP. The term UL preemption trigger frame is for ease of explanation and is not limited thereto. Therefore, UL preemption trigger frames can be collectively referred to as all trigger frames that allow preemption actions / procedures, regardless of their names.

[0246] Here, the UL preemption trigger frame may include the following indication: The UL preemption trigger frame is a trigger frame that triggers one or more STAs that intend to send UL preemption data within a transmission opportunity (TXOP) obtained by the AP to send a UL preemption request.

[0247] For example, the Non-Packet Data Feedback Report Pool (NFRP) trigger frame format can be used for UL preemption trigger frames. In this case, the UL preemption trigger frame can be distinguished from the NFRP trigger frame based on an indication. For example, this indication may include one of the reserved bits in the feedback type subfield within the public information field or the user information field of the UL preemption trigger frame.

[0248] Multiple AIDs can be identified / assigned / scheduled via a UL preemption trigger frame. Furthermore, each of the identified / assigned / scheduled AIDs can correspond to a Resource Unit (RU) tone set index used to transmit the UL preemption request. Additionally, for each RU tone set index, one tone set (e.g., one "used tone") can be associated, or multiple tone sets (e.g., multiple "used tones") can be associated.

[0249] To identify / assign / schedule multiple AIDs in a UL preemption trigger frame, the UL preemption trigger frame can indicate the starting AID and the number of consecutive AIDs starting from the starting AID, depending on the bandwidth of the UL preemption request. For example, 18 consecutive AIDs can be indicated every 20 MHz, or 36 consecutive AIDs can be indicated every 20 MHz.

[0250] Alternatively, a group identifier for one of M (where M is a non-zero integer) AID groups can be indicated via a UL preemption trigger frame. In this case, each AID group may include P AIDs, where the P AIDs may be arranged contiguously or non-contiguously.

[0251] In addition, in order to identify / assign / schedule multiple AIDs in the UL preemption trigger frame, the UL preemption trigger frame may include multiple user information fields.

[0252] In this scenario, i) the AID and ii) the RU tone set index can be indicated in each user information field. That is, a single user information field can be configured for each AID, and a single RU tone set index can be indicated in the corresponding user information field.

[0253] Alternatively, each user information field may indicate: i) the starting AID, ii) the number of consecutive AIDs starting from the starting AID, and iii) the RU tone set index corresponding to the starting AID. That is, since the RU tone set index corresponding to the starting AID is indicated in each user information field, a consecutive RU tone set index equal to the number of AIDs can be indicated.

[0254] Alternatively, each user information field may indicate: i) a group identifier for identifying one of M preset AID groups (where M is a non-zero integer), ii) an AID bitmap for identifying one or more AIDs within an AID group, and iii) an RU tone set index corresponding to the starting AID. That is, each user information field may indicate one or more AIDs within an AID group, and since the RU tone set index corresponding to the starting AID is indicated, a number of consecutive RU tone set indices equal to the number of indicated AIDs may be indicated in the bitmap.

[0255] In addition, the UL preemption trigger frame can be configured with classification criteria to trigger only UL preemption data that meets the classification criteria.

[0256] Based on the existence of UL preemption data (i.e., when attempting UL preemption), the STA device responds to the UL preemption trigger frame by sending a UL preemption request to the AP device (S1302).

[0257] Here, the HE or UHR TB Feedback NDP format can be used to send a UL preemption request (UL preemption message). That is, when UL preemption data exists (i.e., when attempting UL preemption), the STA can send a TB Feedback NDP by powering the tone set (e.g., the tone used) corresponding to its own AID indicated by the UL preemption trigger frame. In this case, upon receiving the TB Feedback NDP, the AP can determine whether to execute a UL preemption request for each AID by detecting the power of each tone set (e.g., the tone used).

[0258] Furthermore, if a classification criterion is configured by the UL preemption trigger frame, the UL preemption request can be sent only if it meets the classification criterion configured by the UL preemption trigger frame. Here, the UL preemption trigger frame may include a flag bit indicating whether a classification criterion is applied, and if a classification criterion is applied according to the flag bit value, the UL preemption request can be sent only if the classification criterion configured by the UL preemption trigger frame is met.

[0259] In addition, UL preemption requests can be sent individually based on the classification of UL preemption data according to classification criteria.

[0260] In steps S1301 and S1302, the PPDU can be configured to include a legacy portion, a SIG portion (e.g., U-SIG, UHR-SIG, etc.), an STF portion (e.g., UHR-STF), an LTF portion (e.g., UHR-LTF), and a data portion.

[0261] Each part (i.e., field) can be divided into multiple subparts / subfields, either wholly or partially. Each field (and its subfields) can be divided into 4µs. N (where N is an integer) is transmitted in units. Additionally, a guard interval (GI) may be included. The common subcarrier frequency spacing value (delta_f = 312.5 kHz / N or 312.5 kHz) N, where N is an integer, can be applied to the entire field, or the first delta_f can be applied to the first part (e.g., the entire legacy part, all / part of the SIG part), and the second delta_f (e.g., a value less than the first delta_f) can be applied to all or part of the remaining part.

[0262] Some of the fields mentioned above can be omitted, and the order of the fields can be changed in various ways. For example, subfields of the signal section can be placed before the STF section, and the remaining subfields of the SIG section can be placed after the STF section.

[0263] The aforementioned legacy portion may include at least one of the following: traditional L-STF (non-HT short training field), L-LTF (non-HT long training field), and L-SIG (non-HT signal field).

[0264] The aforementioned SIG section (e.g., including the U-SIG field, UHR-SIG field, etc.) may include various control information for the PPDU being transmitted. For example, it may include the STF section, the LTF section, and control information for decoding data.

[0265] The STF portion mentioned above may include an STF sequence.

[0266] The LTF portion may include training fields (i.e., LTF sequences) for channel estimation.

[0267] The data section may include user data and groupings for higher levels.

[0268] Trigger frames can be sent via non-HT DUP PPDU format, EHT MU PPDU format, or UHR MU PPDU format.

[0269] Non-HT DUP PPDU means that every 20 MHz is replicated and includes the same legacy PPDU. Here, the legacy PPDU includes... Figure 7 The legacy components in the configuration (L-STF, L-LTF, and L-SIG), but excluding the SIG, STF, or LTF components.

[0270] UHR MU PPDU can include some format features of EHT MU PPDU.

[0271] As mentioned above, the TB feedback NDP format can conform to the HE TB feedback NDP format. Alternatively, a new UHR TB feedback NDP format can be defined. For example, as Figure 12 As shown in (b), the U-SIG can follow the EHT configuration or may include a newly defined general / common SIG in the UHR. It can be a UHR-SIG performing the same role as the EHT-SIG, or it can be a UHR SU or MU PPDU excluding the data portion. The RU tone assignment in the LTF used for the UHR can remain the same as before.

[0272] Afterwards, AP and STA can perform steps 3 and 4 of the UL preemption process described above.

[0273] Figure 13 The methods described in the examples can be derived from... Figure 1 The first device (100) executes. For example, Figure 1 One or more processors (102) of the first device (100) can be configured to perform PPDU exchange with another device via a transceiver (106). Furthermore, one or more memories (104) of the first device (100) can store data for execution by one or more processors (102). Figure 13 The example or instructions of the method described in the example above.

[0274] Figure 14 The operation of an access point for an uplink preemption triggering method according to an embodiment of the present disclosure is shown.

[0275] Figure 14 The operation of an AP device based on the previously proposed method is shown. Figure 14 The examples in this document are for illustrative purposes only and are not intended to limit the scope of this disclosure. They may be omitted depending on the circumstances and / or configuration. Figure 14 Some steps are shown in the diagram.

[0276] Reference Figure 14 The AP device sends a UL preemption trigger frame to multiple STA devices to allow UL preemption (S1401).

[0277] Here, as mentioned above, preemption can refer to the method of sending specific UL data earlier without waiting for the AP or STA to obtain its TXOP. The term UL preemption trigger frame is for ease of explanation and is not limited thereto. Therefore, UL preemption trigger frames can be collectively referred to as all trigger frames that allow preemption actions / procedures, regardless of their names.

[0278] Here, the UL preemption trigger frame may include an indication that the UL preemption trigger frame is an indication that triggers one or more STAs that intend to send a UL preemption request within a transmission opportunity (TXOP) obtained by the AP.

[0279] For example, the Non-Packet Data Feedback Report Pool (NFRP) trigger frame format can be used for UL preemption trigger frames. In this case, the UL preemption trigger frame can be distinguished from the NFRP trigger frame based on an indication. For example, this indication may include one of the reserved bits in the feedback type subfield within the public information field or the user information field of the UL preemption trigger frame.

[0280] Multiple AIDs can be identified / assigned / scheduled via a UL preemption trigger frame. Furthermore, each of the identified / assigned / scheduled AIDs can correspond to a Resource Unit (RU) tone set index used to transmit the UL preemption request. Additionally, for each RU tone set index, one tone set (e.g., one "used tone") can be associated, or multiple tone sets (e.g., multiple "used tones") can be associated.

[0281] To identify / allocate / schedule multiple AIDs in a UL preemption trigger frame, the starting AID can be indicated by the UL preemption trigger frame, and the number of consecutive AIDs starting from the starting AID can be indicated based on the bandwidth of the UL preemption request. For example, 18 consecutive AIDs can be indicated every 20 MHz, or 36 consecutive AIDs can be indicated every 20 MHz.

[0282] Alternatively, a group identifier for one of M (where M is a non-zero integer) AID groups can be indicated by a UL preemption trigger frame. In this case, each AID group can include P AIDs, where the P AIDs can be arranged consecutively or non-consecutively.

[0283] In addition, in order to identify / assign / schedule multiple AIDs in the UL preemption trigger frame, the UL preemption trigger frame may include multiple user information fields.

[0284] In this scenario, i) the AID and ii) the RU tone set index can be indicated in each user information field. That is, a single user information field can be configured for each AID, and a separate RU tone set index can be indicated in the corresponding user information field.

[0285] Alternatively, each user information field may indicate: i) the starting AID, ii) the number of consecutive AIDs starting from the starting AID, and iii) the RU tone set index corresponding to the starting AID. That is, since the RU tone set index corresponding to the starting AID is indicated in each user information field, a consecutive RU tone set index equal to the number of AIDs can be indicated.

[0286] Alternatively, each user information field may indicate: i) a group identifier for identifying one of M preset AID groups (where M is a non-zero integer), ii) an AID bitmap for identifying one or more AIDs within an AID group, and iii) an RU tone set index corresponding to the starting AID. That is, each user information field may indicate one or more AIDs within an AID group, and since the RU tone set index corresponding to the starting AID is indicated, a number of consecutive RU tone set indices equal to the number of indicated AIDs may be indicated in the bitmap.

[0287] In addition, the UL preemption trigger frame can be configured with classification criteria to trigger only UL preemption data that meets the classification criteria.

[0288] The AP device receives a UL preemption request from one or more STAs in response to a UL preemption trigger frame (S1402).

[0289] Here, the HE or UHR TB Feedback NDP format can be used to send the UL preemption request (UL preemption message). That is, when UL preemption data exists (i.e., when attempting UL preemption), the STA can send a TB Feedback NDP by powering the tone set (e.g., the tone used) corresponding to its own AID indicated by the UL preemption trigger frame. In this case, after receiving the TB Feedback NDP, the AP can determine whether to execute a UL preemption request for each AID by detecting the power of each tone set (e.g., the tone used).

[0290] Furthermore, if a classification criterion is configured by the UL preemption trigger frame, a UL preemption request can be sent only if it meets the classification criterion configured by the UL preemption trigger frame. Here, the UL preemption trigger frame may include a flag bit indicating whether a classification criterion is applied, and if a classification criterion is applied according to the flag bit value, the UL preemption request can be sent only if it meets the classification criterion configured by the UL preemption trigger frame.

[0291] In addition, UL preemption requests can be sent individually based on the classification of UL preemption data according to classification criteria.

[0292] In steps S1401 and S1402, the PPDU can be configured to include a legacy portion, a SIG portion (e.g., U-SIG, UHR-SIG, etc.), an STF portion (e.g., UHR-STF), an LTF portion (e.g., UHR-LTF), and a data portion.

[0293] Each part (i.e., field) can be divided into multiple subparts / subfields, either wholly or partially. Each field (and its subfields) can be divided into 4µs. N (where N is an integer) is transmitted in units. Additionally, a guard interval (GI) may be included. The common subcarrier frequency spacing value (delta_f = 312.5 kHz / N or 312.5 kHz) is also included. N, where N is an integer, can be applied to the entire field, or the first delta_f can be applied to the first part (e.g., the entire legacy part, all / part of the SIG part), and the second delta_f (e.g., a value less than the first delta_f) can be applied to all or part of the remaining part.

[0294] Some of the fields mentioned above can be omitted, and the order of the fields can be changed in various ways. For example, subfields of the signal section can be placed before the STF section, and the remaining subfields of the SIG section can be placed after the STF section.

[0295] The aforementioned legacy portion may include at least one of the following: traditional L-STF (non-HT short training field), L-LTF (non-HT long training field), and L-SIG (non-HT signal field).

[0296] The aforementioned SIG section (e.g., including the U-SIG field, UHR-SIG field, etc.) may include various control information for the PPDU being transmitted. For example, it may include the STF section, the LTF section, and control information for decoding data.

[0297] The STF portion mentioned above may include an STF sequence.

[0298] The LTF portion may include training fields (i.e., LTF sequences) for channel estimation.

[0299] The data section may include user data and groupings for higher levels.

[0300] Trigger frames can be sent via non-HT DUP PPDU format, EHT MU PPDU format, or UHR MU PPDU format.

[0301] Non-HT DUP PPDU means that every 20 MHz is replicated and includes the same legacy PPDU. Here, the legacy PPDU includes... Figure 7 The legacy components in the configuration (L-STF, L-LTF, and L-SIG), but excluding the SIG, STF, or LTF components.

[0302] UHR MU PPDU can include some format features of EHT MU PPDU.

[0303] As mentioned above, the TB feedback NDP format can conform to the HE TB feedback NDP format. Alternatively, a new UHR TB feedback NDP format can be defined. For example, as Figure 12 As shown in (b), the U-SIG can follow the EHT configuration or may include a newly defined generic / general SIG in the UHR. It can be a UHR-SIG that performs the same function as the EHT-SIG, or it can be a UHR SU or MU PPDU that excludes the data portion. The RU tone assignment in the LTF for the UHR can be the same as before.

[0304] Afterwards, AP and STA can perform steps 3 and 4 of the UL preemption process described above.

[0305] Figure 14 The methods described in the examples can be derived from... Figure 1 The second device (200) performs the operation. For example, Figure 1 One or more processors (202) of the second device (200) can be configured to perform PPDU exchange with another device via a transceiver (206). Furthermore, one or more memories (204) of the second device (200) can store data for execution by one or more processors (202). Figure 14 The example or instructions of the method described in the example above.

[0306] In existing wireless LAN systems, no preemption method is defined for the STA to transmit data within the TXOP obtained by the AP. In contrast, the UL preemption method according to embodiments of this disclosure allows the STA to transmit UL data within the TXOP obtained by the AP, thereby enabling the transmission and reception of low-latency services, reducing latency, and improving wireless communication efficiency.

[0307] The above embodiments combine the elements and features of this disclosure in a predetermined form. Unless otherwise expressly stated, each element or feature should be considered optional. Each element or feature can be implemented without combination with other elements or features. Furthermore, embodiments of this disclosure may include combinations of certain elements and / or features. The order of operations described in the embodiments of this disclosure may be changed. Some elements or features of one embodiment may be included in other embodiments, or may be replaced by corresponding elements or features of other embodiments. It is clear that embodiments may include combinations of claims where there is no explicit dependency in the claims, or may be included as new claims by amendment after the application.

[0308] It will be apparent to those skilled in the art that this disclosure may be practiced in other specific forms without departing from the essential characteristics of this disclosure. Therefore, the foregoing detailed description should not be construed as restrictive in every respect, but rather as illustrative. The scope of the invention should be determined by a reasonable interpretation of the appended claims, and all variations within the equivalent scope of this disclosure are included within the scope of the invention.

[0309] The scope of this disclosure includes software or machine-executable commands (e.g., operating systems, applications, firmware, programs, etc.) that operate in a device or computer according to methods of various embodiments, and non-transitory computer-readable media that store such software or commands and are executable in a device or computer. Commands that can be used to program a processing system to perform the features described in this disclosure can be stored in a storage medium or a computer-readable storage medium, and the features described in this disclosure can be implemented using a computer program product including such a storage medium. The storage medium may include, but is not limited to, high-speed random access memory, such as DRAM, SRAM, DDR RAM, or other random access solid-state storage devices, and may include non-volatile memory, such as one or more disk storage devices, optical disk storage devices, flash memory devices, or other non-volatile solid-state storage devices. The memory may optionally include one or more storage devices located remotely from the processor. Alternatively, the non-volatile memory devices in the memory may include non-transitory computer-readable storage media. The features described in this disclosure can be stored in any machine-readable medium to control the hardware of a processing system, and can be integrated into software and / or firmware that allows the processing system to interact with other mechanisms using results from embodiments of this disclosure. Such software or firmware may include, but is not limited to, application code, device drivers, operating systems, and execution environments / containers.

[0310] [Industrial Applicability]

[0311] The method proposed in this disclosure is mainly described based on examples applied to IEEE 802.11-based systems and 5G systems, but it can also be applied to various WLAN or wireless communication systems other than those based on IEEE 802.11.

Claims

1. A method comprising: The station (STA) receives an uplink (UL) preemption trigger frame from the access point (AP) to allow UL preemption; as well as Based on the existence of UL preemption data, the STA sends a UL preemption request in response to the UL preemption trigger frame. The UL preemption trigger frame includes the following indication: the UL preemption trigger frame is a trigger frame that triggers one or more STAs that intend to send UL preemption data within a transmission opportunity (TXOP) obtained by the AP to send a UL preemption request.

2. The method according to claim 1, wherein, The Non-Packet Feedback Report Pool (NFRP) trigger frame format was used for the UL preemption trigger frame. Based on the indication, the UL preemption trigger frame is distinguished from the NFRP trigger frame.

3. The method according to claim 1, wherein, The UL preemption trigger frame indicates the start AID, and Based on the bandwidth of the UL preemption request, multiple consecutive AIDs are indicated from the starting AID.

4. The method according to claim 1, wherein, The group identifier of one of M (where M is a non-zero integer) pre-configured AID groups is indicated by the UL preemption trigger frame.

5. The method according to claim 1, wherein, The UL preemption trigger frame includes multiple user information fields, and In each user information field, i) AID and ii) RU tone set index are indicated.

6. The method according to claim 1, wherein, The UL preemption trigger frame includes multiple user information fields, and In each user information field, i) the starting AID, ii) the number of consecutive AIDs starting from the starting AID, and iii) the RU tone set index corresponding to the starting AID are indicated.

7. The method according to claim 1, wherein, The UL preemption trigger frame includes multiple user information fields, and In each user information field, i) a group identifier is used to identify one of M (where M is a non-zero integer) pre-configured AID groups, ii) an AID bitmap is used to identify one or more AIDs within the AID group, and iii) the RU tone set index corresponding to the starting AID is indicated.

8. The method according to claim 1, wherein, The UL preemption request is sent only if the classification criteria configured by the UL preemption trigger frame are met.

9. The method according to claim 1, wherein, The UL preemption trigger frame includes a flag bit that indicates whether the classification criteria are applied.

10. The method according to claim 1, wherein, The UL preemption request is sent individually based on the classification of UL preemption data according to the classification criteria.

11. A station (STA) device in a wireless local area network (WLAN) system, the device comprising: At least one transceiver; as well as At least one processor is connected to the at least one transceiver. Wherein, the at least one processor is configured to: Receive an uplink (UL) preemption trigger frame from the access point (AP) to allow UL preemption; and Based on the existence of UL preemption data, in response to the UL preemption trigger frame, a UL preemption request is sent. The UL preemption trigger frame includes the following indication: the UL preemption trigger frame is a trigger frame that triggers one or more STAs that intend to send UL preemption data within a transmission opportunity (TXOP) obtained by the AP to send a UL preemption request.

12. A method comprising: Uplink (UL) preemption trigger frames are sent from the access point (AP) to multiple stations (STA) to allow UL preemption; as well as In response to the UL preemption trigger frame, the AP receives a UL preemption request from one or more STAs. The UL preemption trigger frame includes the following indication: the UL preemption trigger frame is a trigger frame that triggers one or more STAs that intend to send UL preemption data within a transmission opportunity (TXOP) obtained by the AP to send a UL preemption request.

13. An access point (AP) device in a wireless local area network (WLAN) system, the device comprising: At least one transceiver; as well as At least one processor, said at least one processor being connected to at least one transceiver, Wherein, the at least one processor is configured to: Send uplink (UL) preemption trigger frames to multiple stations (STAs) to allow UL preemption; and In response to the UL preemption trigger frame, a UL preemption request is received from one or more STAs. The UL preemption trigger frame includes the following indication: the UL preemption trigger frame is a trigger frame that triggers one or more STAs that intend to send UL preemption data within a transmission opportunity (TXOP) obtained by the AP to send a UL preemption request.

14. A processing device configured to control a station (STA) in a wireless local area network (WLAN) system, the processing device comprising: At least one processor; as well as At least one computer memory, operatively connected to at least one processor, and based on execution by at least one processor, storing instructions for performing the method according to any one of claims 1 to 11.

15. At least one non-transitory computer-readable medium, said non-transitory computer-readable medium storing at least one instruction, wherein: The at least one instruction is executed by at least one processor to control the device to perform the method according to any one of claims 1 to 11 in a wireless local area network (WLAN) system.

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