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WO2025089709A1 - Procédé et appareil de transmission et de réception de données de préemption de liaison montante dans système lan sans fil - Google Patents

Procédé et appareil de transmission et de réception de données de préemption de liaison montante dans système lan sans fil Download PDF

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Publication number
WO2025089709A1
WO2025089709A1 PCT/KR2024/015770 KR2024015770W WO2025089709A1 WO 2025089709 A1 WO2025089709 A1 WO 2025089709A1 KR 2024015770 W KR2024015770 W KR 2024015770W WO 2025089709 A1 WO2025089709 A1 WO 2025089709A1
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WO
WIPO (PCT)
Prior art keywords
preemption
ppdu
data
sta
request
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PCT/KR2024/015770
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English (en)
Korean (ko)
Inventor
천진영
최진수
임동국
박은성
장인선
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LG Electronics Inc
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LG Electronics Inc
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W72/00—Local resource management
    • H04W72/20—Control channels or signalling for resource management
    • H04W72/21—Control channels or signalling for resource management in the uplink direction of a wireless link, i.e. towards the network
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W72/00—Local resource management
    • H04W72/50—Allocation or scheduling criteria for wireless resources
    • H04W72/56—Allocation or scheduling criteria for wireless resources based on priority criteria
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W74/00—Wireless channel access
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W74/00—Wireless channel access
    • H04W74/04—Scheduled access
    • H04W74/06—Scheduled access using polling
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W84/00—Network topologies
    • H04W84/02—Hierarchically pre-organised networks, e.g. paging networks, cellular networks, WLAN [Wireless Local Area Network] or WLL [Wireless Local Loop]
    • H04W84/10—Small scale networks; Flat hierarchical networks
    • H04W84/12—WLAN [Wireless Local Area Networks]

Definitions

  • the present disclosure relates to a method and device for transmitting and receiving uplink preemption data in a wireless local area network (WLAN) system.
  • WLAN wireless local area network
  • Wi-Fi wireless LAN
  • VHT Very High-Throughput
  • HE High Efficiency
  • EHT Extremely High Throughput
  • technologies for MIMO (Multiple Input Multiple Output) and multi-access point (AP) coordination that support increased bandwidth, efficient utilization of multiple bands, and increased spatial streams are being studied, and in particular, various technologies are being studied to support low latency or real-time traffic.
  • new technologies are being discussed to support ultra-high reliability (UHR), including improvements or extensions of EHT technologies.
  • the technical problem of the present disclosure is to provide a method and device for transmitting and receiving uplink preemption data to one or more stations (STAs) within a TXOP acquired by an access point (AP).
  • STAs stations
  • AP access point
  • an additional technical challenge of the present disclosure is to provide a method and device for requesting additional resources required to transmit more data after uplink preemption data transmission.
  • a method may include: receiving, by a station (STA), an uplink (UL) preemption-related trigger frame for triggering transmission of an UL preemption physical protocol data unit (PPDU) within a transmission opportunity (TXOP) obtained by the AP from an access point (AP); and transmitting, by the STA, the UL preemption PPDU to the AP based on the UL preemption-related trigger frame.
  • the UL preemption PPDU may include a request for more resources required by the STA to transmit more data within the TXOP.
  • a method may include: transmitting, by an access point (AP), to one or more first stations (STAs), an uplink (UL) preemption-related trigger frame for triggering transmission of an UL preemption physical protocol data unit (PPDU) within a transmission opportunity (TXOP) obtained by the AP; and receiving, by the AP, the UL preemption PPDU from the one or more first STAs based on the UL preemption-related trigger frame.
  • the UL preemption PPDU received from the one or more second STAs may include a request for more resources required to transmit more data by the one or more second STAs within the TXOP.
  • an STA that has not acquired a TXOP can quickly transmit uplink data (e.g., low-latency packets, etc.), thereby reducing latency and improving wireless communication efficiency.
  • uplink data e.g., low-latency packets, etc.
  • data to be additionally/subsequently transmitted after uplink preemption data transmission can be transmitted quickly, thereby improving wireless communication efficiency.
  • FIG. 1 illustrates a block diagram of a wireless communication device according to one embodiment of the present disclosure.
  • FIG. 2 is a diagram showing an exemplary structure of a wireless LAN system to which the present disclosure can be applied.
  • FIG. 3 is a diagram for explaining a link setup process to which the present disclosure can be applied.
  • FIG. 4 is a diagram for explaining a backoff process to which the present disclosure can be applied.
  • FIG. 5 is a diagram for explaining a CSMA/CA-based frame transmission operation to which the present disclosure can be applied.
  • FIG. 6 is a drawing for explaining an example of a frame structure used in a wireless LAN system to which the present disclosure can be applied.
  • FIG. 7 is a diagram illustrating examples of PPDUs defined in the IEEE 802.11 standard to which the present disclosure can be applied.
  • FIG. 8 is a diagram showing an exemplary format of a trigger frame to which the present disclosure can be applied.
  • FIG. 9 is a diagram illustrating a UL preemption PPDU according to one embodiment of the present disclosure.
  • FIG. 10 illustrates the operation of a station for an uplink preemption data transmission and reception method according to one embodiment of the present disclosure.
  • FIG. 11 illustrates the operation of an access point for an uplink preemption data transmission and reception method according to one embodiment of the present disclosure.
  • first in one embodiment
  • second component in another embodiment
  • first component in another embodiment may be referred to as a first component in another embodiment
  • the examples of the present disclosure can be applied to various wireless communication systems.
  • the examples of the present disclosure can be applied to a wireless LAN system.
  • the examples of the present disclosure can be applied to a wireless LAN based on IEEE 802.11a/g/n/ac/ax/be standards.
  • the examples of the present disclosure can be applied to a wireless LAN based on a newly proposed IEEE 802.11bn (or UHR) standard.
  • the examples of the present disclosure can be applied to a wireless LAN based on a next-generation standard after IEEE 802.11bn.
  • the examples of the present disclosure can be applied to a cellular wireless communication system.
  • the examples of the present disclosure can be applied to a cellular wireless communication system based on a Long Term Evolution (LTE) series technology of the 3rd Generation Partnership Project (3GPP) standard and a New Radio (5G NR) series technology.
  • LTE Long Term Evolution
  • 3GPP 3rd Generation Partnership Project
  • 5G NR New Radio
  • FIG. 1 illustrates a block diagram of a wireless communication device according to one embodiment of the present disclosure.
  • the first device (100) and the second device (200) illustrated in FIG. 1 may be replaced with various terms such as a terminal, a wireless device, a Wireless Transmit Receive Unit (WTRU), a User Equipment (UE), a Mobile Station (MS), a user terminal (UT), a Mobile Subscriber Station (MSS), a Mobile Subscriber Unit (MSS), a Subscriber Station (SS), an Advanced Mobile Station (AMS), a Wireless terminal (WT), or simply a user.
  • WTRU Wireless Transmit Receive Unit
  • UE User Equipment
  • MS Mobile Station
  • UT a Mobile Subscriber Station
  • MSS Mobile Subscriber Unit
  • SS Subscriber Station
  • AMS Advanced Mobile Station
  • WT Wireless terminal
  • first device (100) and the second device (200) may be replaced with various terms such as an Access Point (AP), a Base Station (BS), a fixed station, a Node B, a base transceiver system (BTS), a network, an Artificial Intelligence (AI) system, a road side unit (RSU), a repeater, a router, a relay, a gateway, etc.
  • AP Access Point
  • BS Base Station
  • BTS base transceiver system
  • AI Artificial Intelligence
  • RSU road side unit
  • RSU road side unit
  • repeater a router, a relay, a gateway, etc.
  • the devices (100, 200) illustrated in FIG. 1 may also be referred to as stations (STAs).
  • STAs stations
  • the devices (100, 200) illustrated in FIG. 1 may be referred to by various terms such as a transmitting device, a receiving device, a transmitting STA, and a receiving STA.
  • the STAs (110, 200) may perform an AP (access point) role or a non-AP role. That is, the STAs (110, 200) in the present disclosure may perform functions of an AP and/or a non-AP.
  • the STAs (110, 200) When the STAs (110, 200) perform an AP function, they may simply be referred to as APs, and when the STAs (110, 200) perform a non-AP function, they may simply be referred to as STAs.
  • the APs in the present disclosure may also be indicated as AP STAs.
  • the first device (100) and the second device (200) can transmit and receive wireless signals through various wireless LAN technologies (e.g., IEEE 802.11 series).
  • the first device (100) and the second device (200) can include interfaces for a medium access control (MAC) layer and a physical layer (PHY) that follow the regulations of the IEEE 802.11 standard.
  • MAC medium access control
  • PHY physical layer
  • the first device (100) and the second device (200) may additionally support various communication standards (for example, standards of 3GPP LTE series, 5G NR series, etc.) other than wireless LAN technology.
  • the device of the present disclosure may be implemented as various devices such as a mobile phone, a vehicle, a personal computer, an Augmented Reality (AR) device, and a Virtual Reality (VR) device.
  • the STA of the present specification may support various communication services such as a voice call, a video call, a data communication, autonomous driving, MTC (Machine-Type Communication), M2M (Machine-to-Machine), D2D (Device-to-Device), and IoT (Internet-of-Things).
  • a first device (100) includes 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) controls the memories (104) and/or the transceivers (106), and may be configured to implement the descriptions, functions, procedures, suggestions, methods, and/or operational flowcharts disclosed in this disclosure.
  • the processor (102) may process information in the memory (104) to generate first information/signal, and then transmit a wireless signal including the first information/signal via the transceiver (106).
  • the processor (102) may receive a wireless signal including second information/signal via the transceiver (106), and then store information obtained from signal processing of the second information/signal in the memory (104).
  • the memory (104) may be connected to the processor (102) and may store various information related to the operation of the processor (102). For example, the memory (104) may perform some or all of the processes controlled by the processor (102), or may store software codes including instructions for performing the descriptions, functions, procedures, proposals, methods, and/or operation flowcharts disclosed in the present disclosure.
  • the processor (102) and the memory (104) may be part of a communication modem/circuit/chip designed to implement a wireless LAN technology (e.g., IEEE 802.11 series).
  • the transceiver (106) may be connected to the processor (102) and may transmit and/or receive wireless signals via one or more antennas (108).
  • the transceiver (106) may include a transmitter and/or a receiver.
  • the transceiver (106) may be used interchangeably with an RF (Radio Frequency) unit.
  • a device may also mean a communication modem/circuit/chip.
  • the second device (200) includes one or more processors (202), 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 be configured to control the memories (204) and/or the transceivers (206), and implement the descriptions, functions, procedures, suggestions, methods, and/or operational flowcharts disclosed in this disclosure.
  • the processor (202) may process information in the memory (204) to generate third information/signal, and then transmit a wireless signal including the third information/signal via the transceiver (206).
  • the processor (202) may receive a wireless signal including fourth information/signal via the transceiver (206), and then store information obtained from signal processing of the fourth information/signal in the memory (204).
  • the memory (204) may be connected to the processor (202) and may store various information related to the operation of the processor (202). For example, the memory (204) may perform some or all of the processes controlled by the processor (202), or may store software codes including instructions for performing the descriptions, functions, procedures, proposals, methods, and/or operational flowcharts disclosed in the present disclosure.
  • the processor (202) and the memory (204) may be part of a communication modem/circuit/chip designed to implement a wireless LAN technology (e.g., IEEE 802.11 series).
  • the transceiver (206) may be connected to the processor (202) and may transmit and/or receive wireless signals via one or more antennas (208).
  • the transceiver (206) may include a transmitter and/or a receiver.
  • the transceiver (206) may be used interchangeably with an RF unit.
  • a device may also mean a communication modem/circuit/chip.
  • one or more protocol layers may be implemented by one or more processors (102, 202).
  • one or more processors (102, 202) may implement one or more layers (e.g., functional layers such as PHY, MAC).
  • One or more processors (102, 202) may generate one or more Protocol Data Units (PDUs) and/or one or more Service Data Units (SDUs) according to the descriptions, functions, procedures, proposals, methods, and/or operational flowcharts disclosed in this disclosure.
  • PDUs Protocol Data Units
  • SDUs Service Data Units
  • One or more processors (102, 202) may generate messages, control information, data, or information according to the descriptions, functions, procedures, proposals, methods, and/or operational flowcharts disclosed in this disclosure.
  • One or more processors (102, 202) can generate signals (e.g., baseband signals) including PDUs, SDUs, messages, control information, data or information according to the functions, procedures, suggestions and/or methodologies disclosed in this disclosure, and provide the signals to one or more transceivers (106, 206).
  • One or more processors (102, 202) can receive signals (e.g., baseband signals) from one or more transceivers (106, 206) and obtain PDUs, SDUs, messages, control information, data or information according to the descriptions, functions, procedures, suggestions, methods and/or operational flowcharts disclosed in this disclosure.
  • signals e.g., baseband signals
  • the one or more processors (102, 202) may be referred to as a controller, a microcontroller, a microprocessor, or a microcomputer.
  • the one or more processors (102, 202) may be implemented by hardware, firmware, software, or a combination thereof.
  • ASICs Application Specific Integrated Circuits
  • DSPs Digital Signal Processors
  • DSPDs Digital Signal Processing Devices
  • PLDs Programmable Logic Devices
  • FPGAs Field Programmable Gate Arrays
  • the descriptions, functions, procedures, suggestions, methods, and/or operational flowcharts disclosed in this disclosure may be implemented using firmware or software, and the firmware or software may be implemented to include modules, procedures, functions, etc.
  • the descriptions, functions, procedures, suggestions, methods and/or operational flowcharts disclosed in this disclosure may be implemented using firmware or software configured to perform one or more of the following: included in one or more processors (102, 202), or stored in one or more memories (104, 204) and driven by one or more of the processors (102, 202).
  • the descriptions, functions, procedures, suggestions, methods and/or operational flowcharts disclosed in this disclosure may be implemented using firmware or software in the form of codes, instructions and/or sets of instructions.
  • One or more memories (104, 204) may be coupled to one or more processors (102, 202) and may store various forms of data, signals, messages, information, programs, codes, instructions, and/or commands.
  • the one or more memories (104, 204) may be comprised of ROM, RAM, EPROM, flash memory, hard drives, registers, cache memory, computer readable storage media, and/or combinations thereof.
  • the one or more memories (104, 204) may be located internally and/or externally to the one or more processors (102, 202). Additionally, the one or more memories (104, 204) may be coupled to the one or more processors (102, 202) via various technologies, such as wired or wireless connections.
  • One or more transceivers (106, 206) can transmit user data, control information, wireless signals/channels, etc., as mentioned in the methods and/or flowcharts of the present disclosure, to one or more other devices.
  • One or more transceivers (106, 206) can receive user data, control information, wireless signals/channels, etc., as mentioned in the descriptions, functions, procedures, suggestions, methods and/or flowcharts of the present disclosure, from one or more other devices.
  • one or more transceivers (106, 206) can be coupled to one or more processors (102, 202) and can transmit and receive wireless signals.
  • 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. Additionally, one or more processors (102, 202) may control one or more transceivers (106, 206) to receive user data, control information, or wireless signals from one or more other devices. Additionally, one or more transceivers (106, 206) may be coupled 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, and the like, as described in the description, function, procedure, proposal, method, and/or operational flowchart, etc.
  • one or more antennas may be multiple physical antennas, or multiple logical antennas (e.g., antenna ports).
  • One or more transceivers (106, 206) may convert received user data, control information, wireless signals/channels, etc. from RF band signals to baseband signals in order to process the received user data, control information, wireless signals/channels, etc. using one or more processors (102, 202).
  • One or more transceivers (106, 206) may convert processed user data, control information, wireless signals/channels, etc. from baseband signals to RF band signals using one or more processors (102, 202).
  • one or more transceivers (106, 206) may include an (analog) oscillator and/or filter.
  • one of the STAs (100, 200) may perform the intended operation of an AP, and the other of the STAs (100, 200) may perform the intended operation of a non-AP STA.
  • the transceivers (106, 206) of FIG. 1 may perform transmission and reception operations of signals (e.g., packets or PPDUs (Physical layer Protocol Data Units) according to IEEE 802.11a/b/g/n/ac/ax/be/bn, etc.).
  • signals e.g., packets or PPDUs (Physical layer Protocol Data Units) according to IEEE 802.11a/b/g/n/ac/ax/be/bn, etc.
  • operations of various STAs generating transmission and reception signals or performing data processing or calculations in advance for transmission and reception signals may be performed in the processors (102, 202) of FIG. 1.
  • an example of an operation for generating a transmit/receive signal or performing data processing or calculation in advance for a transmit/receive signal may include: 1) an operation for determining/acquiring/configuring/computing/decoding/encoding bit information of a field (SIG (signal), STF (short training field), LTF (long training field), Data, etc.) included in a PPDU, 2) an operation for determining/configuring/acquiring time resources or frequency resources (e.g., subcarrier resources) used for the fields (SIG, STF, LTF, Data, etc.) included in a PPDU, 3) an operation for determining/configuring/acquiring specific sequences (e.g., pilot sequences, STF/LTF sequences, extra sequences applied to SIG) used for the fields (SIG, STF, LTF, Data, etc.) included in a PPDU, 4) a power control operation and/or a power saving operation applied to an STA, 5) an operation related to determining/acquiring/acquiring/
  • various information e.g., information related to fields/subfields/control fields/parameters/power, etc.
  • various information e.g., information related to fields/subfields/control fields/parameters/power, etc.
  • various STAs for determining/acquiring/configuring/computing/decoding/encoding transmission/reception signals can be stored in the memory (104, 204) of FIG. 1.
  • downlink means a link for communication from an AP STA to a non-AP STA, and downlink PPDU/packet/signal, etc. can be transmitted and received through the downlink.
  • a transmitter may be part of an AP STA, and a receiver may be part of a non-AP STA.
  • Uplink (UL) means a link for communication from a non-AP STA to an AP STA, and uplink PPDU/packet/signal, etc. can be transmitted and received through the uplink.
  • a transmitter may be part of a non-AP STA, and a receiver may be part of an AP STA.
  • FIG. 2 is a diagram showing an exemplary structure of a wireless LAN system to which the present disclosure can be applied.
  • a wireless LAN supporting transparent STA mobility to a higher layer can be provided through the interaction of multiple components.
  • a BSS Basic Service Set
  • FIG. 2 illustrates an example in which two BSSs (BSS1 and BSS2) exist 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).
  • An ellipse representing a BSS in FIG. 2 can also be understood as representing a coverage area in which STAs included in the corresponding BSS maintain communication. This area can be referred to as a BSA (Basic Service Area). If an STA moves out of the BSA, it cannot directly communicate with other STAs within the corresponding BSA.
  • BSA Basic Service Area
  • an IBSS can have a minimal form consisting of only two STAs.
  • BSS1 consisting of only STA1 and STA2
  • BSS2 consisting of only STA3 and STA4
  • This configuration is possible when STAs can communicate directly without an AP.
  • a LAN can be configured when needed rather than being planned in advance, and this can be called an ad-hoc network.
  • an IBSS does not include an AP, there is no centralized management entity that performs management functions. That is, in an IBSS, STAs are managed in a distributed manner. In IBSS, all STAs can be mobile STAs, and access to distributed systems (DS) is not permitted, forming a self-contained network.
  • DS distributed systems
  • the membership of an STA in a BSS can be dynamically changed by the STA turning on or off, the STA entering or leaving the BSS area, etc.
  • an STA can join the BSS using a synchronization process.
  • an STA In order to access all services of the BSS infrastructure, an STA must be associated with a BSS. This association can be dynamically established and may include the use of a Distribution System Service (DSS).
  • DSS Distribution System Service
  • the direct STA-to-STA distance may be limited by the PHY performance. In some cases, this distance limitation may be sufficient, but in some cases, communication between STAs over longer distances may be required.
  • a distributed system may be configured.
  • DS refers to a structure in which BSSs are interconnected.
  • a BSS may exist as an extended component of a network composed of multiple BSSs, as shown in FIG. 2.
  • DS is a logical concept and can be specified by the characteristics of a distributed system medium (DSM).
  • DSM distributed system medium
  • WM wireless medium
  • DSM distributed system medium
  • Each logical medium is used for a different purpose and is used by different components. These media are neither limited to being the same nor limited to being different.
  • the flexibility of a wireless LAN structure can be explained in that multiple media are logically different.
  • a wireless LAN structure can be implemented in various ways, and each wireless LAN structure can be independently specified by the physical characteristics of each implementation example.
  • a DS can support mobile devices by providing seamless integration of multiple BSSs and providing logical services necessary to handle addresses to destinations.
  • a DS can further include a component called a portal that acts as a bridge for connecting wireless LANs to other networks (e.g., IEEE 802.X).
  • An AP is an entity that enables access to a DS through a WM for associated non-AP STAs, and also has the functionality of an STA. Data movement between a BSS and a DS can be performed through an AP.
  • STA2 and STA3 illustrated in FIG. 2 have the functionality of an STA, and provide a function that allows associated non-AP STAs (STA1 and STA4) to access the DS.
  • all APs are basically STAs, all APs are addressable entities.
  • the address used by an AP for communication on a WM and the address used by an AP for communication on a DSM need not necessarily be the same.
  • a BSS consisting of an AP and one or more STAs can be called an infrastructure BSS.
  • Data transmitted from one of the STA(s) associated with an AP to the STA address of that AP is always received on an uncontrolled port and can be processed by an IEEE 802.1X port access entity.
  • the transmitted data (or frame) can be forwarded to the DS.
  • an Extended Service Set may be established to provide wider coverage.
  • An ESS is a network of arbitrary size and complexity consisting of DS and BSS.
  • An ESS may correspond to a set of BSSs connected to a DS. However, an ESS does not include a DS.
  • An ESS network is characterized by being seen as an IBSS in the LLC (Logical Link Control) 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) transparently to the LLC.
  • APs included in an ESS may have the same SSID (service set identification). The SSID is distinct from the BSSID, which is an identifier of the BSS.
  • the BSSs can be partially overlapped, which is a common configuration used to provide continuous coverage.
  • the BSSs can be physically unconnected, and logically there is no limit to the distance between the BSSs.
  • the BSSs can be physically co-located, which can be used to provide redundancy.
  • one (or more) IBSS or ESS networks can physically co-exist in the same space as one (or more) ESS networks. This can correspond to ESS network configurations such as cases where ad-hoc networks operate at locations where ESS networks exist, cases where physically overlapping wireless networks are configured by different organizations, or cases where two or more different access and security policies are required at the same location.
  • FIG. 3 is a diagram for explaining a link setup process to which the present disclosure can be applied.
  • the link setup process may also be referred to as a session initiation process or a session setup process.
  • the discovery, authentication, association, and security setup processes of the link setup process may be collectively referred to as the association process.
  • the STA may perform a network discovery operation.
  • the network discovery operation may include a scanning operation of the STA. That is, in order for the STA to access the network, it must find a network that it can participate in. The STA must identify a compatible network before participating in the wireless network, and the process of identifying networks existing in a specific area is called scanning.
  • FIG. 3 illustrates a network discovery operation including an active scanning process as an example.
  • active scanning an STA performing scanning transmits a probe request frame to search for APs in the vicinity while moving between channels and waits for a response thereto.
  • a responder transmits a probe response frame to the STA that transmitted the probe request frame as a response to the probe request frame.
  • the responder may be an STA that last transmitted a beacon frame in the BSS of the channel being scanned.
  • the AP transmits a beacon frame, so the AP becomes the responder, and in the IBSS, the STAs within the IBSS take turns transmitting beacon frames, so the responder is not fixed.
  • an STA that transmits a probe request frame on channel 1 and receives a probe response frame on channel 1 can store BSS-related information included in the received probe response frame and move to the next channel (e.g., channel 2) to perform scanning (i.e., transmitting and receiving probe request/response on channel 2) in the same manner.
  • the next channel e.g., channel 2
  • scanning i.e., transmitting and receiving probe request/response on channel 2
  • the scanning operation can also be performed in a passive scanning manner.
  • passive scanning an STA performing scanning moves through channels and waits for a beacon frame.
  • a beacon frame is one of the management frames defined in IEEE 802.11, and is periodically transmitted to notify the existence of a wireless network and to enable an STA performing scanning to find a wireless network and participate in the wireless network.
  • an AP In a BSS, an AP periodically transmits a beacon frame, and in an IBSS, STAs in the IBSS take turns transmitting beacon frames.
  • an STA performing scanning receives a beacon frame, it stores information about the BSS included in the beacon frame and moves to another channel, recording beacon frame information on each channel.
  • An STA receiving a beacon frame stores information related to the BSS included in the received beacon frame, moves to the next channel, and performs scanning on the next channel in the same manner. Comparing active scanning and passive scanning, active scanning has the advantage of lower delay and power consumption than passive scanning.
  • step S320 After the STA discovers the network, an authentication process may be performed in step S320.
  • This authentication process may be referred to as a first authentication process to clearly distinguish it from the security setup operation of step S340 described below.
  • the authentication process includes the STA sending an authentication request frame to the AP, and the AP sending an authentication response frame to the STA in response.
  • the authentication frame used for the authentication request/response corresponds to a management frame.
  • the authentication frame may include information such as an authentication algorithm number, an authentication transaction sequence number, a status code, a challenge text, a Robust Security Network (RSN), a Finite Cyclic Group, etc. These are just some examples of information that may be included in an authentication request/response frame, and may be replaced by other information or may include additional information.
  • RSN Robust Security Network
  • the STA may transmit an authentication request frame to the AP.
  • the AP may determine whether to allow authentication for the STA based on information included in the received authentication request frame.
  • the AP may provide the result of the authentication processing to the STA through an authentication response frame.
  • an association process may be performed in step S330.
  • the association process includes a process in which the STA transmits an association request frame to the AP, and in response, the AP transmits an association response frame to the STA.
  • the association request frame may include information about various capabilities, a beacon listen interval, a service set identifier (SSID), supported rates, supported channels, RSN, mobility domains, supported operating classes, a Traffic Indication Map Broadcast request, interworking service capabilities, etc.
  • the association response frame may include information about various capabilities, a status code, an Association ID (AID), supported rates, an Enhanced Distributed Channel Access (EDCA) parameter set, a Received Channel Power Indicator (RCPI), a Received Signal to Noise Indicator (RSNI), a mobility domain, a timeout interval (e.g., association comeback time), overlapping BSS scan parameters, a TIM broadcast response, a Quality of Service (QoS) map, etc.
  • AID Association ID
  • EDCA Enhanced Distributed Channel Access
  • RCPI Received Channel Power Indicator
  • RSNI Received Signal to Noise Indicator
  • timeout interval e.g., association comeback time
  • overlapping BSS scan parameters e.g., TIM broadcast response
  • a security setup process may be performed in step S340.
  • the security setup process of step S340 may be referred to as an authentication process through a Robust Security Network Association (RSNA) request/response
  • the authentication process of step S320 may be referred to as a first authentication process
  • the security setup process of step S340 may be referred to simply as an authentication process.
  • RSNA Robust Security Network Association
  • the security setup process of step S340 may include a process of performing private key setup, for example, through 4-way handshaking via an Extensible Authentication Protocol over LAN (EAPOL) frame. Additionally, the security setup process may be performed according to a security method not defined in the IEEE 802.11 standard.
  • EAPOL Extensible Authentication Protocol over LAN
  • FIG. 4 is a diagram for explaining a backoff process to which the present disclosure can be applied.
  • the basic access mechanism of MAC is the CSMA/CA (Carrier Sense Multiple Access with Collision Avoidance) mechanism.
  • the CSMA/CA mechanism is also called the Distributed Coordination Function (DCF) of IEEE 802.11 MAC, and basically adopts the "listen before talk" access mechanism.
  • DCF Distributed Coordination Function
  • the AP and/or STA may perform a Clear Channel Assessment (CCA) to sense the wireless channel or medium for a predetermined time period (e.g., a DCF Inter-Frame Space (DIFS)) before starting transmission. If the sensing result determines that the medium is in an idle state, the AP and/or STA may start transmitting frames through the medium.
  • CCA Clear Channel Assessment
  • DIFS DCF Inter-Frame Space
  • the AP and/or STA may not start its own transmission, but may wait for a delay period (e.g., a random backoff period) for medium access and then attempt to transmit frames.
  • a delay period e.g., a random backoff period
  • the IEEE 802.11 MAC protocol provides a Hybrid Coordination Function (HCF).
  • the HCF is based on the DCF and the Point Coordination Function (PCF).
  • the PCF is a polling-based synchronous access method in which all receiving APs and/or STAs periodically poll to receive data frames.
  • the HCF has EDCA (Enhanced Distributed Channel Access) and HCCA (HCF Controlled Channel Access).
  • EDCA is a contention-based access method in which a provider provides data frames to multiple users, and HCCA uses a non-contention-based channel access method using a polling mechanism.
  • the HCF includes a medium access mechanism for improving the QoS (Quality of Service) of a wireless LAN, and can transmit QoS data in both a contention period (CP) and a contention-free period (CFP).
  • QoS Quality of Service
  • a random backoff period When an occupied/busy medium changes to an idle state, multiple STAs may attempt to transmit data (or frames). As a measure to minimize collisions, each STA may select a random backoff count, wait for a corresponding slot time, and then attempt to transmit.
  • the random backoff count has a pseudo-random integer value and may be determined as one of the values in the range of 0 to CW.
  • CW is a contention window parameter value.
  • the CW parameter is initially given CWmin, but may take a double value in case of a transmission failure (e.g., when an ACK for a transmitted frame is not received).
  • the STA continues to monitor the medium while counting down the backoff slots according to the determined backoff count value. If the medium is monitored as occupied, the countdown stops and waits, and when the medium becomes idle, the remaining countdown is resumed.
  • STA3 when a packet to be transmitted reaches the MAC of STA3, STA3 can check that the medium is idle for DIFS and transmit the frame right away. The remaining STAs monitor whether the medium is occupied/busy and wait. In the meantime, data to be transmitted may also occur in each of STA1, STA2, and STA5, and each STA can perform a countdown of the backoff slot according to a random backoff count value selected by each STA after waiting for DIFS when the medium is monitored as idle. Assume that STA2 selects the smallest backoff count value and STA1 selects the largest backoff count value.
  • this example shows a case where the remaining backoff time of STA5 is shorter than the remaining backoff time of STA1 when STA2 finishes the backoff count and starts frame transmission.
  • STA1 and STA5 briefly stop the countdown and wait while STA2 occupies the medium.
  • STA1 and STA5 resume the stopped backoff count after waiting for DIFS. That is, they can start frame transmission after counting down the remaining backoff slots by the remaining backoff time. Since the remaining backoff time of STA5 is shorter than that of STA1, STA5 starts frame transmission. While STA2 occupies the medium, STA4 may also have data to transmit.
  • STA4 From STA4's perspective, when the medium becomes idle, it waits for DIFS, performs a countdown according to the random backoff count value it selected, and starts frame transmission.
  • the remaining backoff time of STA5 coincidentally matches the random backoff count value of STA4, and in this case, a collision may occur between STA4 and STA5. If a collision occurs, neither STA4 nor STA5 will receive an ACK, resulting in a failure in data transmission. In this case, STA4 and STA5 can select a random backoff count value and perform a countdown after doubling the CW value.
  • STA1 waits while the medium is occupied by transmissions from STA4 and STA5, and when the medium becomes idle, it waits for DIFS, and then starts transmitting frames after the remaining backoff time has elapsed.
  • a data frame is a frame used for transmitting data forwarded to a higher layer, and can be transmitted after a backoff performed after DIFS elapses from when the medium becomes idle.
  • a management frame is a frame used for exchanging management information that is not forwarded to a higher layer, and is transmitted after a backoff performed after an IFS such as DIFS or PIFS (Point coordination function IFS) elapses.
  • Subtype frames of the management frame include a beacon, an association request/response, a re-association request/response, a probe request/response, and an authentication request/response.
  • a control frame is a frame used to control access to the medium.
  • the subtype frames of the control frame include RTS (Request-To-Send), CTS (Clear-To-Send), ACK (Acknowledgment), PS-Poll (Power Save-Poll), Block ACK (BlockAck), Block ACK Request (BlockACKReq), NDP notification (null data packet announcement), and Trigger. If the control frame is not a response frame to the previous frame, it is transmitted after the backoff performed after the DIFS (DIFS), and if it is a response frame to the previous frame, it is transmitted without the backoff performed after the SIFS (short IFS).
  • DIFS DIFS
  • SIFS short IFS
  • a QoS (Quality of Service) STA can transmit a frame after a backoff performed after the AIFS (arbitration IFS) for the access category (AC) to which the frame belongs, that is, AIFS[i] (where i is a value determined by the AC), has elapsed.
  • AIFS aromatic IFS
  • the frames for which AIFS[i] can be used can be data frames, management frames, and also control frames that are not response frames.
  • FIG. 5 is a diagram for explaining a CSMA/CA-based frame transmission operation to which the present disclosure can be applied.
  • the CSMA/CA mechanism includes virtual carrier sensing in addition to physical carrier sensing in which an STA directly senses the medium.
  • Virtual carrier sensing is intended to complement problems that may occur in medium access, such as the hidden node problem.
  • the MAC of the STA may utilize a Network Allocation Vector (NAV).
  • NAV Network Allocation Vector
  • the NAV is a value that indicates to other STAs the remaining time until the medium becomes available, by an STA that is currently using or has the right to use the medium. Therefore, the value set as NAV corresponds to the period during which the medium is scheduled to be used by the STA transmitting the corresponding frame, and the STA that receives the NAV value is prohibited from accessing the medium during the corresponding period.
  • the NAV may be set based on the value of the "duration" field of the MAC header of the frame.
  • STA1 wants to transmit data to STA2, and STA3 is in a position to overhear part or all of the frames transmitted and received between STA1 and STA2.
  • a mechanism using RTS/CTS frames may be applied.
  • STA3 may determine that the carrier sensing result of the medium is idle. That is, STA1 may correspond to a hidden node to STA3.
  • STA2 may transmitting, STA3 may determine that the carrier sensing result of the medium is idle. That is, STA2 may correspond to a hidden node to STA3.
  • STAs outside the transmission range of either STA1 or STA2, or STAs outside the carrier sensing range for transmission from STA1 or STA3 may not attempt to occupy the channel during data transmission and reception between STA1 and STA2.
  • STA1 can determine whether a channel is occupied through carrier sensing.
  • STA1 can determine a channel occupied idle state based on energy magnitude or signal correlation detected in the channel.
  • STA1 can determine a channel occupied state using a network allocation vector (NAV) timer.
  • NAV network allocation vector
  • STA1 can transmit an RTS frame to STA2 after performing a backoff if the channel is idle during DIFS.
  • STA2 can transmit a CTS frame, which is a response to the RTS frame, to STA1 after SIFS if it receives the RTS frame.
  • STA3 can set a NAV timer for the subsequently transmitted frame transmission period (e.g., SIFS + CTS frame + SIFS + data frame + SIFS + ACK frame) using the duration information included in the RTS frame.
  • STA3 can set a NAV timer for the subsequently transmitted frame transmission period (e.g., SIFS + data frame + SIFS + ACK frame) using the duration information included in the CTS frame.
  • STA3 can overhear one or more of the RTS or CTS frames from one or more of STA1 or STA2, it can set a NAV accordingly.
  • STA3 can update the NAV timer using the duration information contained in the new frame if it receives a new frame before the NAV timer expires. STA3 does not attempt to access the channel until the NAV timer expires.
  • STA1 receives a CTS frame from STA2, it can transmit a data frame to STA2 after SIFS from the time when reception of the CTS frame is completed. If STA2 successfully receives the data frame, it can transmit an ACK frame in response to the data frame to STA1 after SIFS.
  • STA3 can determine whether the channel is in use through carrier sensing if the NAV timer expires. If STA3 determines that the channel is not in use by other terminals during DIFS after the expiration of the NAV timer, it can attempt channel access after a contention window (CW) following a random backoff has elapsed.
  • CW contention window
  • FIG. 6 is a drawing for explaining an example of a frame structure used in a wireless LAN system to which the present disclosure can be applied.
  • the PHY layer can prepare an MPDU (MAC PDU) to be transmitted by an instruction or primitive (meaning a set of instructions or parameters) from the MAC layer. For example, when a command requesting the start of transmission of the PHY layer is received from the MAC layer, the PHY layer can switch to transmission mode and transmit information (e.g., data) provided from the MAC layer in the form of a frame. In addition, when the PHY layer detects a valid preamble of the received frame, it monitors the header of the preamble and sends a command to the MAC layer notifying the start of reception of the PHY layer.
  • MPDU MPDU
  • an instruction or primitive meaning a set of instructions or parameters
  • PPDU PHY layer Protocol Data Unit
  • a basic PPDU may include a Short Training Field (STF), a Long Training Field (LTF), a SIGNAL (SIG) field, and a Data field.
  • STF Short Training Field
  • LTF Long Training Field
  • SIG SIGNAL
  • PPDU format may consist of only a Legacy-STF (L-STF), a Legacy-LTF (L-LTF), a Legacy-SIG (Legacy-SIG) field, and a Data field.
  • RL-SIG RL-SIG
  • U-SIG non-legacy SIG field
  • non-legacy STF non-legacy LTF
  • xx-SIG xx-SIG
  • xx-LTF e.g., xx represents HT, VHT, HE, EHT, etc.
  • STF is a signal for signal detection, AGC (Automatic Gain Control), diversity selection, precise time synchronization, etc.
  • LTF is a signal for channel estimation, frequency error estimation, etc. STF and LTF can be said to be signals for OFDM physical layer synchronization and channel estimation.
  • the SIG field may include various information related to PPDU transmission and reception.
  • the L-SIG field may consist of 24 bits and may include a 4-bit Rate field, a 1-bit Reserved bit, a 12-bit Length field, a 1-bit Parity field, and a 6-bit Tail field.
  • the RATE field may include information about a modulation and coding rate of data.
  • the 12-bit Length field may include information about the length or time duration of the PPDU.
  • the value of the 12-bit Length field may be determined based on the type of the PPDU. For example, for a non-HT, HT, VHT, or EHT PPDU, the value of the Length field may be determined as a multiple of 3.
  • the value of the Length field can be determined as a multiple of 3 + 1 or a multiple of 3 + 2.
  • the data field may include a SERVICE field, a Physical layer Service Data Unit (PSDU), a PPDU TAIL bit, and, if necessary, padding bits.
  • PSDU Physical layer Service Data Unit
  • PPDU TAIL bit may be used to return the encoder to the 0 state.
  • padding bit may be used to adjust the length of the data field to a predetermined unit.
  • MAC PDU is defined according to various MAC frame formats, and the basic MAC frame consists of a MAC header, frame body, and FCS (Frame Check Sequence).
  • MAC frame consists of MAC PDU and can be transmitted/received through PSDU of the data part of PPDU format.
  • the MAC header includes a Frame Control field, a Duration/ID field, an Address field, etc.
  • the Frame Control field may include control information required for frame transmission/reception.
  • the Duration/ID field may be set to a time for transmitting the corresponding frame, etc.
  • the Address subfields may indicate a receiver address, a transmitter address, a destination address, and a source address of the frame, and some Address subfields may be omitted. For specific details of each subfield of the MAC header, including the Sequence Control, QoS Control, and HT Control subfields, refer to the IEEE 802.11 standard document.
  • Null-Data PPDU (NDP) format refers to a PPDU format that does not include a data field. That is, NDP refers to a frame format that includes a PPDU preamble (i.e., L-STF, L-LTF, L-SIG fields, and additionally, non-legacy SIG, non-legacy STF, non-legacy LTF if present) in a general PPDU format, and does not include the remaining part (i.e., data field).
  • a PPDU preamble i.e., L-STF, L-LTF, L-SIG fields, and additionally, non-legacy SIG, non-legacy STF, non-legacy LTF if present
  • FIG. 7 is a diagram illustrating examples of PPDUs defined in the IEEE 802.11 standard to which the present disclosure can be applied.
  • the basic PPDU format (IEEE 802.11a/g) includes L-LTF, L-STF, L-SIG, and Data fields.
  • the basic PPDU format can also be called a non-HT PPDU format (Fig. 7(a)).
  • the HT PPDU format (IEEE 802.11n) additionally includes HT-SIG, HT-STF, and HT-LFT(s) fields in the basic PPDU format.
  • the HT PPDU format illustrated in Fig. 7(b) may be referred to as an HT-mixed format.
  • an HT-greenfield format PPDU may be defined, which corresponds to a format that does not include L-STF, L-LTF, and L-SIG, and consists of HT-GF-STF, HT-LTF1, HT-SIG, one or more HT-LTF, and Data fields (not illustrated).
  • VHT PPDU format includes VHT SIG-A, VHT-STF, VHT-LTF, and VHT-SIG-B fields in addition to the basic PPDU format (Fig. 7(c)).
  • HE PPDU format (IEEE 802.11ax) additionally includes RL-SIG (Repeated L-SIG), HE-SIG-A, HE-SIG-B, HE-STF, HE-LTF(s), and PE (Packet Extension) fields in the basic PPDU format (Fig. 7(d)).
  • RL-SIG Repeated L-SIG
  • HE-SIG-A HE-SIG-B
  • HE-STF HE-LTF(s)
  • PE Packet Extension
  • some fields may be excluded or their lengths may vary.
  • the HE-SIG-B field is included in a HE PPDU format for multi-users (MUs), and the HE PPDU format for single users (SUs) does not include the HE-SIG-B.
  • a HE trigger-based (TB) PPDU format does not include the HE-SIG-B, and the length of the HE-STF field may vary to 8us.
  • a HE ER (Extended Range) SU PPDU format does not include the HE-SIG-B field, and the length of the HE-SIG-A field may vary to 16us.
  • RL-SIG can be configured identically to L-SIG. The receiving STA can know that the received PPDU is a HE PPDU or an EHT PPDU, described later, based on the presence of RL-SIG.
  • the EHT PPDU format may include the EHT MU (multi-user) PPDU of Fig. 7(e) and the EHT TB (trigger-based) PPDU of Fig. 7(f).
  • the EHT PPDU format is similar to the HE PPDU format in that it includes an RL-SIG following an L-SIG, but it may include a U (universal)-SIG, an EHT-SIG, an EHT-STF, and an EHT-LTF following the RL-SIG.
  • the EHT MU PPDU in Fig. 7(e) 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 transmission and MU transmission.
  • the EHT MU PPDU can correspond to a PPDU for one receiving STA or multiple receiving STAs.
  • the EHT TB PPDU of Fig. 7(f) omits EHT-SIG compared to the EHT MU PPDU.
  • An STA that has received a trigger for UL MU transmission e.g., a trigger frame or TRS (triggered response scheduling)
  • TRS triggered response scheduling
  • the L-STF, L-LTF, L-SIG, RL-SIG, U-SIG (Universal SIGNAL), and EHT-SIG fields can be encoded and modulated and mapped based on a predetermined subcarrier frequency interval (e.g., 312.5 kHz) so that even legacy STAs can attempt to demodulate and decode them. These can be referred to as pre-EHT modulated fields.
  • the EHT-STF, EHT-LTF, Data, and PE fields can be encoded and modulated and mapped based on a predetermined subcarrier frequency interval (e.g., 78.125 kHz) so that they can be demodulated and decoded by an STA that successfully decodes a non-legacy SIG (e.g., U-SIG and/or EHT-SIG) and obtains the information included in the corresponding fields.
  • a predetermined subcarrier frequency interval e.g., 78.125 kHz
  • a non-legacy SIG e.g., U-SIG and/or EHT-SIG
  • EHT modulated fields e.g., U-SIG and/or EHT-SIG
  • the L-STF, L-LTF, L-SIG, RL-SIG, HE-SIG-A, and HE-SIG-B fields may be referred to as pre-HE modulation fields, and the HE-STF, HE-LTF, Data, and PE fields may be referred to as HE modulation fields.
  • the L-STF, L-LTF, L-SIG, and VHT-SIG-A fields may be referred to as pre-VHT modulation fields
  • the VHT STF, VHT-LTF, VHT-SIG-B, and Data fields may be referred to as VHT modulation fields.
  • the U-SIG included in the EHT PPDU format of Fig. 7 can be configured based on, for example, two symbols (e.g., two consecutive OFDM symbols).
  • Each symbol (e.g., OFDM symbol) for the U-SIG can have a duration of 4us, and the U-SIG can have a total duration of 8us.
  • Each symbol of the U-SIG can be used to transmit 26 bits of information.
  • each symbol of the U-SIG can be transmitted and received based on 52 data tones and 4 pilot tones.
  • U-SIG can be configured in 20MHz units. For example, when an 80MHz PPDU is configured, the same U-SIG can be replicated in 20MHz units. That is, four identical U-SIGs can be included in an 80MHz PPDU. When the bandwidth exceeds 80MHz, for example, for a 160MHz PPDU, the U-SIG of the first 80MHz unit and the U-SIG of the second 80MHz unit can be different.
  • a uncoded bits can be transmitted, and a first symbol of U-SIG (e.g., U-SIG-1 symbol) can transmit the first X bits of information out of the total A bits of information, and a second symbol of U-SIG (e.g., U-SIG-2 symbol) can transmit the remaining Y bits of information out of the total A bits of information.
  • the A bits of information e.g., 52 uncoded bits
  • the tail field can be used to terminate the trellis of the convolutional decoder and can be set to 0, for example.
  • the A bit information transmitted by U-SIG can be divided into version-independent bits and version-dependent bits.
  • U-SIG may be included in a new PPDU format (e.g., UHR PPDU format) not shown in FIG. 7, 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-dependent bits may be different.
  • the size of the version-independent bits of U-SIG can be fixed or variable.
  • the version-independent bits can be assigned only to U-SIG-1 symbols, or to both U-SIG-1 symbols and U-SIG-2 symbols.
  • the version-independent bits and the version-dependent bits can be called by various names, such as the first control bit and the second control bit.
  • the version-independent bits of U-SIG may include a 3-bit PHY version identifier, which may indicate the PHY version (e.g., EHT, UHR, etc.) of the transmitted and 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 relates to UL communication, and the second value of the UL/DL flag field relates to DL communication.
  • the version-independent bits of U-SIG may include information about the length of a TXOP (transmission opportunity) and information about a BSS color ID.
  • the version-dependent bits of the U-SIG may contain information that directly or indirectly indicates the type of the PPDU (e.g., SU PPDU, MU PPDU, TB PPDU, etc.).
  • the U-SIG may further include information about bandwidth, information about an MCS technique applied to a non-legacy SIG (e.g., EHT-SIG or UHR-SIG, etc.), information indicating whether a dual carrier modulation (DCM) technique (e.g., a technique for achieving an effect similar to frequency diversity by reusing the same signal on two subcarriers) is applied to the non-legacy SIG, information about the number of symbols used for the non-legacy SIG, information about whether the non-legacy SIG is generated over the entire band, etc.
  • DCM dual carrier modulation
  • Some of the information required for PPDU transmission and reception may be included in the U-SIG and/or the non-legacy SIG (e.g., EHT-SIG or UHR-SIG, etc.).
  • 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 cyclic prefix (CP) length e.g., EHT-LTF/EHT-STF or UHR-LTF/UHR-STF, etc.
  • information about the length of the non-legacy LTF and the cyclic prefix (CP) length e.g., information about the guard interval (GI) applied to the non-legacy LTF
  • information about the preamble puncturing applicable to the PPDU e.g., information about the resource unit (RU) allocation, etc.
  • RU resource unit
  • Preamble puncturing may mean transmission of a PPDU in which no signal is present in one or more frequency units within the bandwidth of the PPDU.
  • the size of the frequency unit (or the resolution of the preamble puncturing) may be defined as 20 MHz, 40 MHz, etc.
  • preamble puncturing may be applied to a PPDU bandwidth greater than a predetermined size.
  • non-legacy SIGs such as HE-SIG-B, EHT-SIG, etc. may include control information for the receiving STA.
  • the non-legacy SIG may be transmitted through at least one symbol, and one symbol may have a length of 4 us.
  • Information about the number of symbols used for EHT-SIG may be included in a previous SIG (e.g., HE-SIG-A, U-SIG, etc.).
  • Non-legacy SIGs such as HE-SIG-B, EHT-SIG, etc.
  • HE-SIG-B may contain common fields and user-specific fields. Common fields and user-specific fields may be coded separately.
  • the common field may be omitted.
  • the common field may be omitted, and multiple STAs may receive a PPDU (e.g., a data field of a PPDU) over the same frequency band.
  • a PPDU e.g., a data field of a PPDU
  • multiple users may receive a PPDU (e.g., a data field of a PPDU) over different frequency bands.
  • the number of user-specific fields can be determined based on the number of users.
  • One user block field can include at most two user fields.
  • Each user field can be associated with an MU-MIMO allocation or associated with a non-MU-MIMO allocation.
  • the common field may include CRC bits and Tail bits, the length of the CRC bits may be determined as 4 bits, the length of the Tail bits may be determined as 6 bits and may be set to 000000.
  • the common field may include RU allocation information.
  • the RU allocation information may include information about the location of RUs to which multiple users (i.e., multiple receiving STAs) are allocated.
  • An RU may include multiple subcarriers (or tones). An RU may be used when transmitting signals to multiple STAs based on the OFDMA technique. An RU may also be defined when transmitting signals to one STA. Resources may be allocated in RU units for non-legacy STFs, non-legacy LTFs, and Data fields.
  • an applicable size of RU can be defined.
  • the RU may be defined identically or differently for the applicable PPDU format (e.g., HE PPDU, EHT PPDU, UHR PPDU, etc.).
  • the RU arrangements of HE PPDU and EHT PPDU may be different.
  • the applicable RU size, RU number, RU position, DC (direct current) subcarrier position and number, null subcarrier position and number, guard subcarrier position and number, etc. for each PPDU bandwidth can be referred to as a tone plan.
  • a tone plan for a wide bandwidth can be defined in the form of multiple repetitions of a tone plan for a low bandwidth.
  • RUs of different sizes can be defined, such as 26-tone RU, 52-tone RU, 106-tone RU, 242-tone RU, 484-tone RU, 996-tone RU, 2 ⁇ 996-tone RU, 3 ⁇ 996-tone RU, etc.
  • a multiple RU is distinct from multiple individual RUs and corresponds to a group of subcarriers consisting of multiple RUs.
  • one MRU can be defined as 52+26-tones, 106+26-tones, 484+242-tones, 996+484-tones, 996+484+242-tones, 2 ⁇ 996+484-tones, 3 ⁇ 996-tones, or 3 ⁇ 996+484-tones.
  • multiple RUs constituting one MRU may or may not be consecutive in the frequency domain.
  • the specific size of the RU may be reduced or expanded. Therefore, the specific size of each RU (i.e., the number of corresponding tones) in the present disclosure is not limited and is exemplary. In addition, within a given bandwidth (e.g., 20, 40, 80, 160, 320 MHz, ...) in the present disclosure, the number of RUs may vary depending on the RU size.
  • each field in the PPDU formats of FIG. 7 are exemplary, and the scope of the present disclosure is not limited by the names.
  • the examples of the present disclosure can be applied not only to the PPDU format exemplified in FIG. 7, but also to a new PPDU format in which some fields are excluded and/or some fields are added based on the PPDU formats of FIG. 7.
  • FIG. 8 is a diagram showing an exemplary format of a trigger frame to which the present disclosure can be applied.
  • a trigger frame may allocate resources for one or more TB PPDU transmissions and may request TB PPDU transmissions.
  • the trigger frame may also include other information required by an STA transmitting a TB PPDU in response thereto.
  • the trigger frame may include common info and user info list fields in the frame body.
  • the common information field may include information common to one or more TB PPDU transmissions requested by the trigger frame, such as trigger type, UL length, presence of a subsequent trigger frame (e.g., More TF), whether CS (channel sensing) is required, UL BW (bandwidth), etc.
  • 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, BFRP (Beamforming Report Poll), MU-BAR (multi user-block acknowledgement request), MU-RTS (multi user-request to send), BSRP (Buffer Status Report Poll), GCR (groupcast with retries) MU-BAR, BQRP (Bandwidth Query Report Poll), and NFRP (NDP Feedback Report Poll), respectively, and the values 8 to 15 are defined as reserved.
  • BFRP Beamforming Report Poll
  • MU-BAR multi user-block acknowledgement request
  • MU-RTS multi user-request to send
  • BSRP Buffer Status Report Poll
  • GCR groupcast with retries
  • MU-BAR BQRP (Bandwidth Query Report Poll)
  • NFRP NDP Feedback Report Poll
  • the trigger dependent common info subfield may include information that is optionally included based on the trigger type.
  • a special user info field may be included within the trigger frame.
  • the special user info field does not contain user-specific information, but rather contains extended common information not provided in the common information field.
  • a user info list contains zero or more user info fields.
  • Figure 8 illustrates an example of an EHT variant user info field format.
  • the AID12 subfield basically indicates that it is a user information field for an STA having the corresponding AID.
  • the AID12 field has a predetermined specific value, it may be utilized for other purposes, such as allocating a random access (RA)-RU, or being configured in the form of a special user info field.
  • the special user info field is a user info field that does not include user specific information but includes extended common information that is not provided in the common information field.
  • the special user info field can be identified by the AID12 value of 2007, and the special user info field flag subfield in the common information field can indicate whether the special user info field is included.
  • the RU allocation subfield can indicate the size and location of RU/MRU.
  • 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 common information field, etc.
  • Figure 9 is a diagram showing an exemplary format of an NFRP trigger frame.
  • the non-data packet (NDP) feedback reporting procedure is used by an AP to collect non-channel sounding feedback from multiple non-AP STAs.
  • the AP transmits an NDP feedback report pool (NFRP) trigger frame to request NDP feedback report responses from a number of non-AP STAs identified in the AID range scheduled in the trigger frame.
  • the NDP feedback report response from a non-AP STA is a TB feedback NDP.
  • the non-AP STA uses the information conveyed in the NFRP trigger frame to determine whether it is scheduled, and if so, to derive parameters for transmitting the response.
  • the UL BW subfield in the Common Information field indicates the bandwidth of the NDP Feedback Report Response.
  • one or more subfields within the common information field may be reserved.
  • STBC space-time block coding
  • UL spatial reuse subfield e.g., an uplink space-time block coding (STBC) subfield, an UL spatial reuse subfield, a pre-FEC (forward error correction) padding factor subfield, a PE (packet extension) disambiguity subfield, etc.
  • PE packet extension
  • a scheduled non-AP STA is identified by a range of AIDs.
  • the starting AID subfield defines the first AID in the range of AIDs scheduled to respond to an NFRP trigger frame.
  • a value of 0 in the feedback type subfield indicates a resource request, and all other values are reserved.
  • the UL target receive power subfield indicates the expected received signal power, measured at the AP's antenna connector and averaged at the antenna, for the non-legacy portion of a trigger-based (TB) PPDU transmitted on the allocated RU.
  • the Number of spatially multiplexed users subfield indicates the number of STAs multiplexed to the same set of tones in the same RU, encoded as the number of STAs minus 1.
  • preemption may refer to a method for transmitting specific UL data earlier without waiting for an AP or STA to acquire its own TXOP, or to transmit specific data earlier than other UL data within its own TXOP. In other words, preemption may be applied to data transmission of an STA that has not acquired its TXOP.
  • LL traffic For example, specific data transmitted based on preemption may be packets/traffic that require low latency (LL).
  • LL traffic is difficult to predict, has a relatively small size, and must be transmitted quickly.
  • a preemption technique can be applied to support an STA that does not hold a TXOP to transmit LL traffic during a TXOP.
  • the application of preemption-based data transmission is not limited to LL traffic, and can also be applied to traffic for other purposes.
  • STAs attempting preemption can transmit a preemption request packet (PPDU).
  • PPDU preemption request packet
  • the TXOP holder that receives the preemption request can transmit a UL preemption trigger to allow UL preemption.
  • the TXOP holder can arbitrarily transmit a UL preemption trigger without a separate preemption request.
  • the UL preemption trigger can be transmitted alone or together with other DL PPDU(s).
  • the UL preemption trigger can be transmitted alone in the form of a Non-HT DUP (Duplicate) PPDU or a DL MU PPDU, or the UL preemption trigger can be transmitted in the form of a DL MU PPDU together with other DL PPDU(s).
  • a Non-HT DUP Downlicate
  • DL MU PPDU Downlink MU PPDU
  • the UL preemption trigger can be transmitted in the form of a DL MU PPDU together with other DL PPDU(s).
  • the present disclosure proposes a transmission of a UL preemption trigger and the procedure thereafter (hereinafter referred to as 'UL preemption procedure' or 'UL preemption trigger procedure').
  • the UL preemption procedure from the perspective of the AP, which is the TXOP holder, can be as follows.
  • Step 1) The AP can transmit a UL preemption trigger frame to allow UL preemption.
  • a non-data packet (NDP) feedback report pool (NFRP) trigger frame can be used as the UL preemption trigger frame.
  • NDP non-data packet
  • NFRP feedback report pool
  • Step 2) the AP can receive UL preemption message/request(s).
  • UL preemption message/request is trigger-based (TB) feedback NDP.
  • Step 3 the AP may transmit a trigger frame to (trigger) UL preemption data transmission of STA(s) based on the information of the UL preemption message/request received in step 2.
  • xIFS e.g., SIFS
  • the AP may transmit a trigger frame to (trigger) UL preemption data transmission of STA(s) based on the information of the UL preemption message/request received in step 2.
  • Step 4 And after xIFS (e.g., SIFS), the AP can receive UL TB PPDU(s) from STA(s). If there is a request for more resources from the STA(s) here (e.g., a more resource request is included in the UL TB PPDU transmission), the AP can repeat the procedure of steps 3 and 4 again. In this case, ACK (acknowledgement) information for the UL PPDU can be transmitted together with the trigger frame in the procedure of step 3. A detailed description of a method for requesting more resources will be described later.
  • ACK acknowledgement
  • Step 5 And after xIFS (e.g., SIFS) or after a certain time (a predetermined time or an arbitrary timing), the AP may transmit an ACK or NACK (negative ACK) message/information to the STA(s) that transmitted the UL TB PPDU.
  • the ACK or NACK message/information may be transmitted together with the trigger frame of Step 3 or another PPDU.
  • a specific description of the ACK or NACK message/information is provided below.
  • the UL preemption procedure from the perspective of STA(s) associated with an AP that is a TXOP holder is as follows.
  • Step 1) STAs receive a UL preemption trigger frame, and STAs attempting UL preemption may prepare to transmit UL preemption message/request (e.g., TB feedback NDP)(s) as instructed by the UL preemption trigger frame.
  • UL preemption message/request e.g., TB feedback NDP
  • Step 2 And after xIFS (e.g., SIFS), STAs that are indicated/identified by the UL preemption trigger frame and want to attempt UL preemption can transmit a UL preemption message/request in the designated resource.
  • xIFS e.g., SIFS
  • STAs that are indicated/identified by the UL preemption trigger frame and want to attempt UL preemption can transmit a UL preemption message/request in the designated resource.
  • An example of a UL preemption message/request can be TB Feedback NDP.
  • Step 3 And after xIFS (e.g., SIFS) or at a timing randomly determined by the AP, the STAs that transmitted the UL preemption message/request in Step 2 receive a trigger frame from the AP for (triggering) transmission of UL preemption data and determine whether they can transmit UL preemption data.
  • xIFS e.g., SIFS
  • Step 4 And after xIFS (e.g., SIFS), the STA(s) indicated/identified from the trigger frame of step 3 can configure a UL preemption PPDU carrying UL preemption data, and transmit the UL preemption PPDU to the AP according to the indication of the trigger frame of step 3.
  • the STA(s) can transmit a request for additional resources (more resources) (e.g., including a request for additional resources when transmitting the UL preemption PPDU). In this case, the procedures of steps 3 and 4 can be repeated.
  • ACK information for the UL PPDU can be received together with the trigger frame in step 3.
  • the Ack information for the UL PPDU can be received together with the Trigger frame in the procedure of step 3.
  • Step 5 the STAs that transmitted the UL preemption PPDU can receive an ACK or NACK message/information from the AP.
  • the ACK or NACK message/information can be received together with the trigger frame of Step 3 or another PPDU.
  • a specific description of the ACK or NACK message/information is provided below.
  • Example 1 Method for requesting additional resources when transmitting UL preemption data/PPDU
  • Step 1 when a UL preemption message/request is triggered with a non-data packet (NDP) feedback report pool (NFRP) trigger frame, the AP cannot know the buffer size or queue size, etc., for the UL preemption data for the STA(s) attempting to transmit the UL preemption data.
  • NDP non-data packet
  • NFRP feedback report pool
  • the STA may request additional UL resources from the AP when transmitting the UL preemption PPDU in step 4 described above.
  • additional resources can be requested from the AP by including a QoS Control field or a buffer status report (BSR) control (BSR Control) subfield in the UL Preemption PPDU.
  • BSR buffer status report
  • An STA can transmit a BSR using the QoS Control field or the BSR Control subfield, which may include a Queue size subfield indicating the amount of buffered traffic or a TXOP Duration Requested subfield indicating the duration that the STA determines is necessary for the next TXOP.
  • a new subfield for requesting additional resources for UL preemption data e.g., a required latency subfield or a buffer size subfield for UL preemption
  • These newly defined subfields can indicate values (e.g., requested latency or buffer size) in units such as milliseconds (ms) or octets (or multiples thereof, e.g., multiples of 4 ms or multiples of 256 octets).
  • the size of the resource requested as the additional resource can be determined as follows.
  • various types for resource requests can be defined, and the STA can select one type and request additional resources according to the type.
  • Example 1 It may be a resource request for the remaining data that was not sent among the UL preemption packets/data that were previously transmitted in the UL preemption message/request.
  • the STA transmits the UL preemption message/request to the AP, it may request additional resources to transmit the remaining data that was not sent among the UL preemption data that the STA intended to transmit.
  • Example 2 It can be a resource request for all remaining UL preemption data including other UL preemption packets/data in addition to the value of Example 1 (i.e., the size of the requested additional resources).
  • the STA when the STA transmits a UL preemption message/request to the AP, the STA can request additional resources for transmitting all remaining UL preemption data including other UL preemption data other than the UL preemption data that the STA intended to transmit.
  • Example 3 In addition to the value of Example 2 (i.e., the size of the requested additional resources), the STA may request resources for all remaining UL data that it needs/wants to transmit. In other words, the STA may request additional resources to transmit all remaining UL data that it needs/wants to transmit as well as all remaining UL preemption data.
  • an STA can request additional resources from the AP by selecting one of the values (i.e., the size of the additional resources requested) from examples 1, 2, and 3 above.
  • the STA can indicate the size of the requested resource along with the indication of the type of resource request.
  • the STA can indicate to the AP what value the additional resource request is for (i.e., what type of additional resource is requested).
  • a subfield indicating this e.g., a resource type subfield
  • the STA can select multiple types for the resource request and indicate the size of the resource requested for each type.
  • multiple UL resource values e.g., queue sizes
  • an indication of which value the resource request is for i.e., which type of additional resource is requested
  • Table 1 illustrates the subfields for requesting additional resources.
  • the subfield for additional resource request may include a resource type subfield indicating which data the STA is requesting resources for and a queue size subfield indicating the size of the requested resource. If the STA requests additional resources for multiple resource types, the subfield for the additional resource request may be included in multiple UL preemption PPDUs.
  • the more data subfield in the MAC header of the UL preemption PPDU can be set to '1'.
  • the more data subfield was used to notify STAs in power saving (PS) mode that the AP has buffered data for the STA, and was set to '0' otherwise.
  • the STA can set the more data subfield in the MAC header to '1'.
  • a new subfield may be included in the MAC header to indicate the size of the additional resources requested by the STA.
  • Embodiment 2 the AP may transmit an ACK or NACK message/information for UL preemption data/PPDU transmitted by one or more STAs.
  • the AP may transmit an ACK or NACK message/information to the STA(s) through a Multi-STA BlockAck frame or a Multi-TID BlockAck frame.
  • the value of the Block Ack bitmap corresponding to the UL preemption data, MSDU (MAC service data unit), may be determined as ACK when '1' is determined, and may be determined as NACK when '0' is determined.
  • the AP can transmit a 3-step trigger frame together with the block ACK (BA: blockACK) frame in the 5 steps described above (referred to as 'transmission T').
  • the AP can also allocate UL resources for the MSDU (i.e., UL preemption data) corresponding to the NACK message/information. Since latency is important due to the characteristics of the UL preemption data, the AP can support rapid transmission by immediately reallocating resources.
  • the STA(s) receive the 'transmission T' including its AID
  • the STA(s) can transmit part or all of the remaining UL preemption data, including the data of the MSDU corresponding to the NACK in the BA frame, according to the resources allocated by the trigger frame. Since latency is important due to the characteristics of the UL preemption data, the STA can immediately retransmit. For example, the already transmitted MSDUs can be stored in a buffer until the ACK message/information is received.
  • FIG. 9 is a diagram illustrating a UL preemption PPDU according to one embodiment of the present disclosure.
  • the format of the UL TB PPDU carrying UL preemption data (referred to as UL preemption PPDU) may be UHR TB PPDU.
  • UHR TB PPDU may include some format features of HE TB PPDU and EHT TB PPDU.
  • UHR TB PPDU may be composed of L-STF, L-LTF, L-SIG, RL-SIG, U-SIG, UHR-STF, UHR-LTF(s), and data fields.
  • U-SIG may follow the configuration of EHT or may be a universal/common SIG newly defined in UHR.
  • UHR-STF and UHR-LTF may follow the configuration of EHT-STF and EHT-LTF or may be newly defined in UHR, but the feature that only UHR-STF/LTF included in the frequency range where UL resources are allocated, such as the data part, is transmitted can be maintained.
  • Non-HT DUP PPDU means that the same legacy PPDU is copied and included every 20MHz.
  • the legacy PPDU means that it includes the legacy part (L-STF, L-LTF, and L-SIG) in the configuration of FIG. 7, and does not include the SIG part, STF part, and LTF part.
  • the trigger frame mentioned in the above 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 FIG. 7).
  • FIG. 10 illustrates the operation of a station for an uplink preemption data transmission and reception method according to one embodiment of the present disclosure.
  • Fig. 10 illustrates the operation of a STA device based on the previously proposed methods.
  • the example in Fig. 10 is provided for convenience of explanation and does not limit the scope of the present disclosure. Some of the step(s) illustrated in Fig. 10 may be omitted depending on the situation and/or setting.
  • a STA device receives a UL preemption related trigger frame for triggering transmission of a UL preemption PPDU within a TXOP acquired by the AP device from the AP device (S1001).
  • preemption may refer to a method of transmitting specific UL data earlier without waiting for an AP or STA to acquire its TXOP.
  • the term UL preemption related trigger frame is for convenience of explanation and the present disclosure is not limited thereto. Accordingly, the UL preemption related trigger frame may collectively refer to all trigger frames that trigger UL preemption data transmission regardless of the name.
  • the STA device transmits a UL preemption PPDU to the AP device based on a UL preemption-related trigger frame (S1002).
  • the UL preemption PPDU may include a request for additional resources (more resources) required by the STA to transmit more data within the TXOP.
  • the UL preemption related trigger frame can be received. That is, the AP device can transmit the UL preemption related trigger frame to the STA(s) that transmitted the UL preemption request.
  • the size of the additional resource may correspond to the resource size required for transmission of the remaining first UL preemption data that was not sent within the UL preemption PPDU among the UL preemption data related to the UL preemption request (resource type 1).
  • the size of the additional resource may correspond to the resource size required for transmission of the first UL preemption data and all remaining second UL preemption data that are not related to the UL preemption request (resource type 2).
  • the size of the additional resource may correspond to the resource size required for transmission of the first UL preemption data, the second UL preemption data, and all UL data required to be transmitted by the STA device (resource type 3).
  • the request for the additional resource may include a resource type indicating for which data the additional resource is requested and a size of the additional resource. That is, the STA device may inform the AP device as a resource type what data the request for the additional resource is to transmit. For example, it may indicate which resource type among the resource types 1 to 3 corresponds to which.
  • a request for the above additional resources may be transmitted within the Quality of Service (QoS) control field or the buffer status report (BSR) control field (within a defined/configured subfield) included in the UL preemption PPDU.
  • QoS Quality of Service
  • BSR buffer status report
  • a request for the additional resources may be transmitted within a specific subfield within the MAC (medium access control) header of the UL preemption PPDU, with the more data subfield set to 1.
  • the STA device may receive a block ACK frame including ACK/NACK information (i.e., a block ACK bitmap) for an MSDU (MAC service data unit) transmitted within the UL preemption PPDU from the AP device.
  • the block ACK frame and a trigger frame that triggers transmission of the UL preemption PPDU may be transmitted together (for example, transmitted as one MAC frame or within one PPDU, or multiplexed and transmitted in the frequency/time domain).
  • the STA device may receive a frame including a NACK (negative acknowledgment) for an MSDU (MAC service data unit) transmitted within the UL preemption PPDU from the AP device and UL resource allocation.
  • the STA device may transmit, to the AP device, i) data of the MSDU and ii) some or all of the remaining UL preemption data, to which the NACK is indicated, based on the UL resource allocation.
  • a PPDU may be composed of a legacy part, a SIG part (e.g., U-SIG, UHR-SIG, etc.), an STF part (e.g., UHR-STF), an LTF part (e.g., UHR-LTF), and a data part.
  • a SIG part e.g., U-SIG, UHR-SIG, etc.
  • an STF part e.g., UHR-STF
  • an LTF part e.g., UHR-LTF
  • All or part of any part may be divided into multiple sub-parts/sub-fields.
  • Each field (and its sub-fields) may be transmitted in units of 4us * N (N is an integer).
  • a guard interval may be included.
  • the subfields of the signal part may be placed before the STF part, and the remaining subfields of the SIG part may be placed after the STF part.
  • the legacy portion described above may include at least one of a conventional L-STF (Non-HT Short Training Field), L-LTF (Non-HT Long Training Field), and L-SIG (Non-HT Signal Field).
  • L-STF Non-HT Short Training Field
  • L-LTF Non-HT Long Training Field
  • L-SIG Non-HT Signal Field
  • the above-mentioned SIG-part may include various control information for the transmitted PPDU.
  • it may include the STF-part, the LTF-part, and control information for decoding data.
  • the above-described STF portion may contain an STF sequence.
  • the above-described LTF portion may include a training field (i.e., an LTF sequence) for channel estimation.
  • a training field i.e., an LTF sequence
  • the data-part described above may include user data and may include packets for upper layers.
  • the above-described trigger frame can be transmitted in Non-HT DUP PPDU format, EHT MU PPDU or UHR MU PPDU format.
  • Non-HT DUP PPDU means that the same legacy PPDU is copied and included every 20MHz.
  • the legacy PPDU here includes the legacy parts (L-STF, L-LTF, and L-SIG) in the configuration of Fig. 7, and does not include the SIG part, STF part, or LTF part.
  • UHR MU PPDU may include some format features of EHT MU PPDU.
  • the method described in the example of FIG. 10 may be performed by the first device (100) of FIG. 1.
  • one or more processors (102) of the first device (100) of FIG. 1 may be configured to perform PPDU exchange with other devices via the transceiver(s) (106).
  • one or more memories (104) of the first device (100) may store commands for performing the method described in the example of FIG. 10 or the examples described above when executed by one or more processors (102).
  • FIG. 11 illustrates the operation of an access point for an uplink preemption data transmission and reception method according to one embodiment of the present disclosure.
  • Fig. 11 illustrates the operation of an AP device based on the proposed methods.
  • the example in Fig. 11 is provided for convenience of explanation and does not limit the scope of the present disclosure. Some of the step(s) illustrated in Fig. 11 may be omitted depending on the situation and/or setting.
  • an AP device transmits a UL preemption related trigger frame to one or more first STA devices to trigger transmission of a UL preemption PPDU within a TXOP acquired by the AP (S1101).
  • preemption may refer to a method of transmitting specific UL data earlier without waiting for an AP or STA to acquire its TXOP.
  • the term UL preemption related trigger frame is for convenience of explanation and the present disclosure is not limited thereto. Accordingly, the UL preemption related trigger frame may collectively refer to all trigger frames that trigger UL preemption data transmission regardless of the name.
  • the AP device receives a UL preemption PPDU based on a UL preemption-related trigger frame from one or more first STAs (S1102).
  • the UL preemption PPDU received from one or more second STAs may include a request for more resources required to transmit more data by one or more of the second STAs in the TXOP.
  • the UL preemption related trigger frame can be received. That is, the AP device can transmit the UL preemption related trigger frame to the STA(s) that transmitted the UL preemption request.
  • the size of the additional resource may correspond to the resource size required for transmission of the remaining first UL preemption data that was not sent within the UL preemption PPDU among the UL preemption data related to the UL preemption request (resource type 1).
  • the size of the additional resource may correspond to the resource size required for transmission of the first UL preemption data and all remaining second UL preemption data that are not related to the UL preemption request (resource type 2).
  • the size of the additional resource may correspond to the resource size required for transmission of the first UL preemption data, the second UL preemption data, and all UL data required to be transmitted by the STA device (resource type 3).
  • the request for the additional resource may include a resource type indicating for which data the additional resource is requested and a size of the additional resource. That is, the STA device may inform the AP device as a resource type what data the request for the additional resource is to transmit. For example, it may indicate which resource type among the resource types 1 to 3 corresponds to which.
  • a request for the above additional resources may be transmitted within the Quality of Service (QoS) control field or the buffer status report (BSR) control field (within a defined/configured subfield) included in the UL preemption PPDU.
  • QoS Quality of Service
  • BSR buffer status report
  • a request for the additional resources may be transmitted within a specific subfield within the MAC (medium access control) header of the UL preemption PPDU, with the more data subfield set to 1.
  • the AP device may transmit to the STA device a block ACK frame including ACK/NACK information (i.e., a block ACK bitmap) for the MSDU (MAC service data unit) conveyed within the UL preemption PPDU.
  • the block ACK frame and a trigger frame that triggers transmission of the UL preemption PPDU may be transmitted together (for example, transmitted as one MAC frame or within one PPDU, or multiplexed and transmitted in the frequency/time domain).
  • the AP device may transmit to one or more STA devices a frame including a negative acknowledgment (NACK) for the MSDU (MAC service data unit) conveyed within the UL preemption PPDU and UL resource allocation.
  • the one or more STA devices may transmit, to the AP device, i) data of the MSDU to which the NACK is indicated and ii) part or all of the remaining UL preemption data.
  • a PPDU may be composed of a legacy part, a SIG part (e.g., U-SIG, UHR-SIG, etc.), an STF part (e.g., UHR-STF), an LTF part (e.g., UHR-LTF), and a data part.
  • a SIG part e.g., U-SIG, UHR-SIG, etc.
  • an STF part e.g., UHR-STF
  • an LTF part e.g., UHR-LTF
  • All or part of any part may be divided into multiple sub-parts/sub-fields.
  • Each field (and its sub-fields) may be transmitted in units of 4us * N (N is an integer).
  • a guard interval may be included.
  • the subfields of the signal part may be placed before the STF part, and the remaining subfields of the SIG part may be placed after the STF part.
  • the legacy portion described above may include at least one of a conventional L-STF (Non-HT Short Training Field), L-LTF (Non-HT Long Training Field), and L-SIG (Non-HT Signal Field).
  • L-STF Non-HT Short Training Field
  • L-LTF Non-HT Long Training Field
  • L-SIG Non-HT Signal Field
  • the above-mentioned SIG-part may include various control information for the transmitted PPDU.
  • it may include the STF-part, the LTF-part, and control information for decoding data.
  • the above-described STF portion may contain an STF sequence.
  • the above-described LTF portion may include a training field (i.e., an LTF sequence) for channel estimation.
  • a training field i.e., an LTF sequence
  • the data-part described above may include user data and may include packets for upper layers.
  • the above-described trigger frame can be transmitted in Non-HT DUP PPDU format, EHT MU PPDU or UHR MU PPDU format.
  • Non-HT DUP PPDU means that the same legacy PPDU is copied and included every 20MHz.
  • the legacy PPDU here includes the legacy parts (L-STF, L-LTF, and L-SIG) in the configuration of Fig. 7, and does not include the SIG part, STF part, or LTF part.
  • UHR MU PPDU may include some format features of EHT MU PPDU.
  • the method described in the example of FIG. 11 may be performed by the second device (200) of FIG. 1.
  • one or more processors (202) of the second device (200) of FIG. 1 may be configured to perform PPDU exchange with other devices via the transceiver(s) (206).
  • one or more memories (204) of the second device (200) may store commands for performing the method described in the example of FIG. 11 or the examples described above when executed by one or more processors (202).
  • an STA can transmit UL data within a TXOP acquired by an AP, and thus, by transmitting and receiving low latency traffic, latency can be reduced and wireless communication efficiency can be increased.
  • the scope of the present disclosure includes software or machine-executable instructions (e.g., an operating system, an application, firmware, a program, etc.) that cause operations according to the various embodiments to be executed on a device or a computer, and a non-transitory computer-readable medium having such software or instructions stored thereon and executable on the device or computer.
  • Instructions that can be used to program a processing system to perform the features described in the present disclosure can be stored on/in a storage medium or a computer-readable storage medium, and a computer program product including such a storage medium can be used to implement the features described in the present disclosure.
  • the storage medium can include, but is not limited to, high-speed random access memory, such as DRAM, SRAM, DDR RAM, or other random access solid state memory devices, and can include non-volatile memory, such as one or more magnetic disk storage devices, optical disk storage devices, flash memory devices, or other non-volatile solid state storage devices.
  • the memory optionally includes one or more storage devices remotely located from the processor(s).
  • the memory or alternatively the non-volatile memory device(s) within the memory comprises a non-transitory computer-readable storage medium.
  • the features described in this disclosure may be incorporated into software and/or firmware stored on any one of the machine-readable media to control the hardware of the processing system and to allow the processing system to interact with other mechanisms that utilize results according to embodiments of the present disclosure.
  • Such software or firmware may include, but is not limited to, application code, device drivers, operating systems, and execution environments/containers.
  • the method proposed in this disclosure has been described with a focus on examples applied to IEEE 802.11-based systems, but can be applied to various wireless LANs or wireless communication systems in addition to IEEE 802.11-based systems.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Mobile Radio Communication Systems (AREA)

Abstract

Sont divulgués un procédé et un appareil de transmission et de réception de données de préemption de liaison montante dans un système LAN sans fil. Un procédé selon un mode de réalisation de la présente divulgation peut comprendre les étapes consistant à : recevoir, par une STA, en provenance d'un AP, une trame de déclenchement liée à la préemption UL pour déclencher la transmission d'une PPDU de préemption UL dans une TXOP obtenue par l'AP ; et transmettre, par la STA, la PPDU de préemption UL à l'AP sur la base de la trame de déclenchement liée à la préemption UL.
PCT/KR2024/015770 2023-10-23 2024-10-17 Procédé et appareil de transmission et de réception de données de préemption de liaison montante dans système lan sans fil Pending WO2025089709A1 (fr)

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Citations (3)

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Publication number Priority date Publication date Assignee Title
US20220400503A1 (en) * 2022-06-29 2022-12-15 Intel Corporation Communication of asynchronous ultra-low latency transmissions within a synchronized transmission opportunity (s-txop)
WO2023284648A1 (fr) * 2021-07-13 2023-01-19 华为技术有限公司 Procédé et appareil d'accès à un canal
US20230208774A1 (en) * 2023-01-04 2023-06-29 Intel Corporation Preemption for low latency application

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Publication number Priority date Publication date Assignee Title
WO2023284648A1 (fr) * 2021-07-13 2023-01-19 华为技术有限公司 Procédé et appareil d'accès à un canal
US20220400503A1 (en) * 2022-06-29 2022-12-15 Intel Corporation Communication of asynchronous ultra-low latency transmissions within a synchronized transmission opportunity (s-txop)
US20230208774A1 (en) * 2023-01-04 2023-06-29 Intel Corporation Preemption for low latency application

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Title
KISEON RYU (NXP): "TXOP preemption follow up", IEEE DRAFT; 11-23-1174-00-0UHR-TXOP-PREEMPTION-FOLLOW-UP, vol. 802.11 UHR, no. 0, 7 August 2023 (2023-08-07), US, pages 1 - 10, XP068204656 *
LIUMING LU (OPPO): "Multi-AP Coordination for Low Latency Traffic Delivery: Usage Scenarios and potential features", IEEE DRAFT; 11-23-0046-00-0UHR-MULTI-AP-COORDINATION-FOR-LOW-LATENCY-TRAFFIC-DELIVERY-USAGE-SCENARIOS-AND-POTENTIAL-FEATURES, vol. 802.11 UHR, no. 0, 13 March 2023 (2023-03-13), US, pages 1 - 15, XP068201618 *

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