Method and device for performing delay-sensitive traffic transmission / reception operation in wireless LAN system

Abstract

Disclosed are a method and device for operating in a wireless LAN system. A method performed by a first non-access point (AP) MLD according to an embodiment of the present disclosure may comprise the steps in which: a first STA, which is associated with the first non-AP MLD, receives a first trigger frame including at least one delay bound from a first AP; the first STA transmits, to the first AP, a first frame including first information related to the size of first delay-sensitive traffic to be transmitted within the at least one delay bound; the first STA receives, from the first AP, a second trigger frame including second information related to a first resource unit for the first delay-sensitive traffic; and the first STA transmits, to the first AP, a second frame including the first delay-sensitive traffic on the basis of the second trigger frame.

Description

Method and device for performing delay-sensitive traffic transmission and reception operations in a wireless LAN system

[0001] The present disclosure relates to channel access operations in a wireless local area network (WLAN) system, and more particularly, to a method and device for performing delay-sensitive traffic transmission and reception operations in a next-generation wireless LAN system.

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

[0003] To provide a more advanced wireless communication environment, improved technologies for Extremely High Throughput (EHT) are being discussed. For example, technologies for Multiple Input Multiple Output (MIMO), which supports increased bandwidth, efficient utilization of multiple bands, and increased spatial streams, and for coordination of multiple access points (APs), are being studied. In particular, various technologies are being studied to support low latency or real-time traffic. Furthermore, new technologies are being discussed to support ultra-high reliability (UHR), including improvements or extensions of EHT technology.

[0004] The technical problem of the present disclosure is to provide a method and device for performing delay-sensitive traffic transmission and reception operations in a wireless LAN system.

[0005] The technical problems to be achieved in the present disclosure are not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly understood by a person having ordinary skill in the technical field to which the present disclosure belongs from the description below.

[0006] According to one embodiment of the present disclosure, a method performed by a first non-access point (AP) multi-link device (MLD) may include: receiving, by a first STA affiliated with the first non-AP MLD, a first trigger frame from a first AP, the first trigger frame including at least one delay bound; transmitting, by the first STA, to the first AP, a first frame including first information related to a size of first delay-sensitive traffic to be transmitted within the at least one delay bound; receiving, by the first STA, from the first AP a second trigger frame including second information related to a first resource unit for the first delay-sensitive traffic; and transmitting, by the first STA, a second frame including the first delay-sensitive traffic to the first AP based on the second trigger frame.

[0007] In accordance with another embodiment of the present disclosure, a method performed by a first access point (AP) multi-link device (MLD) may include: transmitting, by a first AP affiliated to the first AP MLD, a first trigger frame including at least one delay bound to a first station (STA); receiving, by the first AP, from the first STA, a first frame including first information related to a size of first delay-sensitive traffic to be transmitted within the at least one delay bound; transmitting, by the first AP, a second trigger frame including second information related to a first resource unit for the first delay-sensitive traffic to the first STA; and receiving, by the first AP, a second frame including the first delay-sensitive traffic from the first STA based on the second trigger frame.

[0008] According to various embodiments of the present disclosure, a method and device for performing delay-sensitive traffic transmission and reception operations in a wireless LAN system can be provided.

[0009] By various embodiments of the present disclosure, not only the amount of delay-sensitive traffic to be transmitted but also the urgency information of the data can be efficiently transmitted and received.

[0010] The effects that can be obtained from the present disclosure are not limited to the effects mentioned above, and other effects that are not mentioned will be clearly understood by a person having ordinary skill in the art to which the present disclosure pertains from the description below.

[0011] The accompanying drawings, which are incorporated in and are part of the detailed description to aid in understanding the present disclosure, provide embodiments of the present disclosure and, together with the detailed description, describe the technical features of the present disclosure.

[0012] FIG. 1 illustrates a block diagram of a wireless communication device according to one embodiment of the present disclosure.

[0013] FIG. 2 is a diagram showing an exemplary structure of a wireless LAN system to which the present disclosure can be applied.

[0014] FIG. 3 is a diagram for explaining a link setup process to which the present disclosure can be applied.

[0015] FIG. 4 is a diagram for explaining a backoff process to which the present disclosure can be applied.

[0016] FIG. 5 is a diagram for explaining a CSMA / CA-based frame transmission operation to which the present disclosure can be applied.

[0017] 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.

[0018] FIG. 7 is a diagram illustrating examples of PPDUs defined in the IEEE 802.11 standard to which the present disclosure can be applied.

[0019] FIG. 8 is a drawing showing an exemplary format of a trigger frame to which the present disclosure can be applied.

[0020] FIG. 9 is a flowchart illustrating a method performed by a first STA according to one embodiment of the present disclosure.

[0021] FIG. 10 is a flowchart illustrating a method performed by a first AP according to one embodiment of the present disclosure.

[0022] FIG. 11, FIG. 12 and FIG. 13 are diagrams for explaining a procedure for transmitting and receiving LL traffic within a delay bound according to one embodiment of the present disclosure.

[0023] FIG. 14, FIG. 15 and FIG. 16 are diagrams for explaining a procedure for transmitting and receiving information on whether LLT traffic is urgent, according to one embodiment of the present disclosure.

[0024] Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. The detailed description set forth below, together with the accompanying drawings, is intended to explain exemplary embodiments of the present disclosure and is not intended to represent the only embodiments in which the present disclosure may be practiced. The following detailed description includes specific details to provide a thorough understanding of the present disclosure. However, one of ordinary skill in the art will appreciate that the present disclosure may be practiced without these specific details.

[0025] In some cases, to avoid obscuring the concepts of the present disclosure, known structures and devices may be omitted or illustrated in block diagram form focusing on the core functions of each structure and device.

[0026] In the present disclosure, when a component is said to be "connected," "coupled," or "connected" to another component, this may include not only a direct connection but also an indirect connection in which another component exists between them. Furthermore, the terms "comprises" or "has" in the present disclosure specify the presence of the mentioned features, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof.

[0027] In this disclosure, terms such as “first,” “second,” etc. are used only to distinguish one component from another and are not used to limit the components, and do not limit the order or importance between the components unless specifically stated otherwise. Accordingly, within the scope of this disclosure, a first component in one embodiment may be referred to as a second component in another embodiment, and similarly, a second component in one embodiment may be referred to as a first component in another embodiment.

[0028] The terminology used herein is for the purpose of describing particular embodiments and is not intended to limit the scope of the claims. As used in the description of the embodiments and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly dictates otherwise. The term "and / or" as used herein may refer to any one of the associated enumerated items, or is meant to refer to and encompass any and all possible combinations of two or more of them. Furthermore, the use of " / " between words in this disclosure has the same meaning as "and / or" unless otherwise stated.

[0029] The examples of the present disclosure can be applied to various wireless communication systems. For example, the examples of the present disclosure can be applied to a wireless LAN system. For example, the examples of the present disclosure can be applied to a wireless LAN based on the IEEE 802.11a / g / n / ac / ax / be standards. Furthermore, the examples of the present disclosure can be applied to a wireless LAN based on the newly proposed IEEE 802.11bn (or UHR) standard. Additionally, the examples of the present disclosure can be applied to a wireless LAN based on the next-generation standard after IEEE 802.11bn. Furthermore, the examples of the present disclosure can be applied to a cellular wireless communication system. For example, the examples of the present disclosure can be applied to a cellular wireless communication system based on the LTE (Long Term Evolution) series of technologies and the 5G NR (New Radio) series of technologies of the 3rd Generation Partnership Project (3GPP) standard.

[0030] Below, technical features to which examples of the present disclosure can be applied are described.

[0031] FIG. 1 illustrates a block diagram of a wireless communication device according to one embodiment of the present disclosure.

[0032] 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 WTRU (Wireless Transmit Receive Unit), a UE (User Equipment), an MS (Mobile Station), a UT (user terminal), an MSS (Mobile Subscriber Station), an MSS (Mobile Subscriber Unit), an SS (Subscriber Station), an AMS (Advanced Mobile Station), a WT (Wireless terminal), or simply a user. In addition, the first device (100) and the second device (200) may be replaced with various terms such as an access point (AP), a BS (Base Station), a fixed station, a Node B, a BTS (Base Transceiver System), a network, an AI (Artificial Intelligence) system, an RSU (road side unit), a repeater, a router, a relay, a gateway, etc.

[0033] The devices (100, 200) illustrated in FIG. 1 may also be referred to as stations (STAs). For example, the devices (100, 200) illustrated in FIG. 1 may be referred to by various terms such as transmitting device, receiving device, transmitting STA, and receiving STA. For example, the STAs (110, 200) may perform an AP (access point) role or a non-AP role. That is, in the present disclosure, the STAs (110, 200) may perform the functions of an AP and / or a non-AP. 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. In addition, in the present disclosure, the APs may also be referred to as AP STAs.

[0034] Referring to FIG. 1, 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 provisions of the IEEE 802.11 standard.

[0035] In addition, the first device (100) and the second device (200) may additionally support various communication standards (e.g., 3GPP LTE series, 5G NR series standards, etc.) other than wireless LAN technology. In addition, the device of the present disclosure may be implemented as various devices such as a mobile phone, a vehicle, a personal computer, an AR (Augmented Reality) device, a VR (Virtual Reality) device, etc. In addition, the STA of the present specification may support various communication services such as voice calls, video calls, data communications, autonomous driving, MTC (Machine-Type Communication), M2M (Machine-to-Machine), D2D (Device-to-Device), and IoT (Internet-of-Things).

[0036] A first device (100) includes one or more processors (102) and one or more memories (104), and may further include one or more transceivers (106) and / or one or more antennas (108). The processor (102) controls the memories (104) and / or the transceivers (106), and may be configured to implement the descriptions, functions, procedures, proposals, methods, and / or operational flowcharts disclosed in the present disclosure. For example, the processor (102) may process information in the memories (104) to generate first information / signals, and then transmit a wireless signal including the first information / signals via the transceivers (106). Furthermore, the processor (102) may receive a wireless signal including second information / signals via the transceivers (106), and then store information obtained from signal processing of the second information / signals in the memory (104). The memory (104) may be connected to the processor (102) and may store various information related to the operation of the processor (102). For example, the memory (104) may perform some or all of the processes controlled by the processor (102), or may store software code including instructions for performing the descriptions, functions, procedures, proposals, methods, and / or operation flowcharts disclosed in the present disclosure. Here, 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. In the present disclosure, a device may also mean a communication modem / circuit / chip.

[0037] The second device (200) includes one or more processors (202), one or more memories (204), and may further include one or more transceivers (206) and / or one or more antennas (208). The processor (202) controls the memories (204) and / or the transceivers (206), and may be configured to implement the descriptions, functions, procedures, proposals, methods, and / or operational flowcharts disclosed in the present disclosure. For example, the processor (202) may process information in the memory (204) to generate third information / signals, and then transmit a wireless signal including the third information / signals via the transceivers (206). Furthermore, the processor (202) may receive a wireless signal including fourth information / signals via the transceivers (206), and then store information obtained from signal processing of the fourth information / signals in the memory (204). The memory (204) may be connected to the processor (202) and may store various information related to the operation of the processor (202). For example, the memory (204) may perform some or all of the processes controlled by the processor (202), or may store software code including instructions for performing the descriptions, functions, procedures, proposals, methods, and / or operation flowcharts disclosed in the present disclosure. Here, 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. In the present disclosure, a device may also mean a communication modem / circuit / chip.

[0038] Hereinafter, the hardware elements of the device (100, 200) will be described in more detail. Although not limited thereto, one or more protocol layers may be implemented by one or more processors (102, 202). For example, one or more processors (102, 202) may implement one or more layers (e.g., functional layers such as PHY, MAC). One or more processors (102, 202) may generate one or more 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 the present disclosure. 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 the present 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, proposals and / or methods disclosed in the present 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, proposals, methods and / or operational flowcharts disclosed in the present disclosure.

[0039] One or more processors (102, 202) may be referred to as a controller, a microcontroller, a microprocessor, or a microcomputer. One or more processors (102, 202) may be implemented by hardware, firmware, software, or a combination thereof. For example, one or more Application Specific Integrated Circuits (ASICs), one or more Digital Signal Processors (DSPs), one or more Digital Signal Processing Devices (DSPDs), one or more Programmable Logic Devices (PLDs), or one or more Field Programmable Gate Arrays (FPGAs) may be included in one or more processors (102, 202). The descriptions, functions, procedures, proposals, 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, proposals, methods and / or operation flowcharts disclosed in this disclosure may be implemented using firmware or software configured to perform one or more processors (102, 202) or stored in one or more memories (104, 204) and driven by one or more processors (102, 202). The descriptions, functions, procedures, proposals, methods and / or operation flowcharts disclosed in this disclosure may be implemented using firmware or software in the form of codes, instructions and / or sets of instructions.

[0040] 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 configured as 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.

[0041] 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, proposals, methods and / or flowcharts of the present disclosure, from one or more other devices. For example, one or more transceivers (106, 206) can be coupled to one or more processors (102, 202) and can transmit and receive wireless signals. For example, one or more processors (102, 202) can control one or more transceivers (106, 206) to transmit user data, control information, or wireless signals to one or more other devices. 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, or the like, as referred to in the descriptions, functions, procedures, proposals, methods, and / or operational flowcharts disclosed in the present disclosure, via one or more antennas (108, 208). In the present disclosure, one or more antennas may be multiple physical antennas or multiple logical antennas (e.g., antenna ports). One or more transceivers (106, 206) can 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 user data, control information, wireless signals / channels, etc. processed by one or more processors (102, 202) from baseband signals to RF band signals. For this purpose, one or more transceivers (106, 206) may include an (analog) oscillator and / or filter.

[0042] For example, 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. For example, 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.). In addition, in the present disclosure, operations in which various STAs generate transmission and reception signals or perform data processing or calculations in advance for transmission and reception signals may be performed in the processors (102, 202) of FIG. 1. For example, an example of an operation for generating a transmission / reception signal or performing data processing or operation in advance for a transmission / reception signal may include 1) an operation for determining / obtaining / 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 / obtaining time resources or frequency resources (e.g., subcarrier resources) used for a field (SIG, STF, LTF, Data, etc.) included in a PPDU, 3) an operation for determining / configuring / obtaining a specific sequence (e.g., a pilot sequence, an STF / LTF sequence, an extra sequence applied to SIG) used for a field (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 / obtaining / configuring / computing / decoding / encoding an ACK signal, etc. Additionally, in the examples below, various information (e.g., information related to fields / subfields / control fields / parameters / power, etc.) used by various STAs for determining / acquiring / configuring / computing / decoding / encoding transmission / reception signals can be stored in the memory (104, 204) of FIG. 1.

[0043] Hereinafter, downlink (DL) refers to a link for communication from an AP STA to a non-AP STA, and downlink PPDUs / packets / signals, etc. can be transmitted and received through the downlink. In downlink communication, the transmitter may be part of an AP STA, and the receiver may be part of a non-AP STA. Uplink (UL) refers to a link for communication from a non-AP STA to an AP STA, and uplink PPDUs / packets / signals, etc. can be transmitted and received through the uplink. In uplink communication, the transmitter may be part of a non-AP STA, and the receiver may be part of an AP STA.

[0044] FIG. 2 is a diagram showing an exemplary structure of a wireless LAN system to which the present disclosure can be applied.

[0045] The structure of a wireless LAN system can be composed of multiple components. Through the interaction of multiple components, a wireless LAN that supports transparent STA mobility to the upper layer can be provided. A Basic Service Set (BSS) corresponds to a basic building block of a wireless LAN. FIG. 2 illustrates, by way of example, the existence of two BSSs (BSS1 and BSS2) and the inclusion of two STAs as members of each BSS (STA1 and STA2 are included in BSS1, and STA3 and STA4 are included in BSS2). The oval 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 Basic Service Area (BSA). When an STA moves outside of a BSA, it cannot directly communicate with other STAs within the BSA.

[0046] If we do not consider the DS illustrated in Figure 2, the most basic type of BSS in a wireless LAN is an Independent BSS (IBSS). For example, an IBSS can have a minimal form consisting of only two STAs. For example, assuming other components are omitted, BSS1 consisting of only STA1 and STA2, or BSS2 consisting of only STA3 and STA4, can be representative examples of an IBSS, respectively. Such a configuration is possible when the STAs can communicate directly without an AP. Furthermore, in this type of WLAN, a LAN can be configured when needed rather than being planned in advance, and this can be called an ad-hoc network. Since an IBSS does not include an AP, there is no centralized management entity. That is, in an IBSS, STAs are managed in a distributed manner. In IBSS, all STAs can be mobile STAs, and access to distributed systems (DS) is not permitted, forming a self-contained network.

[0047] An STA's membership in a BSS can dynamically change, for example, when an STA is turned on or off, or when an STA enters or leaves a BSS area. To become a member of a BSS, an STA can join the BSS using a synchronization process. To access all services in the BSS infrastructure, an STA must be associated with the BSS. This association can be dynamically established and may involve the use of a Distribution System Service (DSS).

[0048] In a wireless LAN, the direct STA-to-STA distance can be limited by PHY performance. While this distance limit may be sufficient in some cases, communication between STAs over longer distances may be required in other cases. To support extended coverage, a distributed system (DS) can be configured.

[0049] DS refers to a structure in which BSSs are interconnected. Specifically, a BSS may exist as an extended component of a network composed of multiple BSSs, as illustrated in Figure 2. DS is a logical concept and can be specified by the characteristics of a distributed system medium (DSM). In this regard, the Wireless Medium (WM) and DSM can be logically distinguished. Each logical medium is used for a different purpose and by different components. These media are neither limited to being identical nor limited to being different. This logical difference between multiple media explains the flexibility of the WLAN architecture (DS architecture or other network architectures). In other words, the WLAN architecture can be implemented in various ways, and the physical characteristics of each implementation can independently specify the WLAN architecture.

[0050] A DS can support mobile devices by providing seamless integration of multiple BSSs and the logical services necessary to handle addresses to destinations. Additionally, a DS may further include a component called a portal, which acts as a bridge for connecting wireless LANs to other networks (e.g., IEEE 802.X).

[0051] 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. For example, STA2 and STA3 illustrated in FIG. 2 have the functionality of an STA and provide the function of allowing associated non-AP STAs (STA1 and STA4) to access the DS. In addition, since 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 do not necessarily have to be the same. A BSS consisting of an AP and one or more STAs can be referred to as an infrastructure BSS.

[0052] 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. In addition, if the controlled port is authenticated, the transmitted data (or frame) can be forwarded to the DS.

[0053] In addition to the structure of the DS described above, an extended service set (ESS) may be established to provide wider coverage.

[0054] An ESS is a network of arbitrary size and complexity, consisting of DSs and BSSs. 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 appearing as an IBSS at the Logical Link Control (LLC) layer. STAs within an ESS can communicate with each other, and mobile STAs can move from one BSS to another (within the same ESS) transparently to the LLC. APs within an ESS may have the same SSID (service set identification). The SSID is distinct from the BSSID, which is the identifier of the BSS.

[0055] In a wireless LAN system, no assumptions are made about the relative physical locations of BSSs, and all of the following configurations are possible: BSSs can be partially overlapping, which is commonly used to provide continuous coverage. BSSs can also be physically disconnected, and there is no logical distance limit between them. BSSs can also be physically co-located, which can be used to provide redundancy. Furthermore, one (or more) IBSS or ESS networks can physically co-exist with one (or more) ESS networks. This can occur in cases where an ad-hoc network operates at the same location as an ESS network, where physically overlapping wireless networks are configured by different organizations, or where two or more different access and security policies are required at the same location.

[0056] FIG. 3 is a diagram for explaining a link setup process to which the present disclosure can be applied.

[0057] For an STA to set up a link and transmit and receive data on a network, it must first discover the network, perform authentication, establish an association, and complete security authentication procedures. The link setup process can also be referred to as the session initiation process or session setup process. Furthermore, the discovery, authentication, association, and security setup processes of the link setup process can be collectively referred to as the association process.

[0058] In step S310, the STA may perform a network discovery operation. This network discovery operation may include scanning operations by the STA. That is, for the STA to access a network, it must search for available networks. Before joining a wireless network, the STA must identify compatible networks. The process of identifying networks in a specific area is called scanning.

[0059] Scanning methods include active scanning and passive scanning. Figure 3 illustrates a network discovery operation including an active scanning process as an example. In active scanning, an STA performing scanning transmits a probe request frame to discover any APs in the vicinity while moving between channels and waits for a response. The responder transmits a probe response frame in response to the STA that transmitted the probe request frame. Here, the responder may be the STA that last transmitted a beacon frame in the BSS of the channel being scanned. In the BSS, the AP transmits the beacon frame, so the AP becomes the responder. In the IBSS, the STAs within the IBSS take turns transmitting beacon frames, so the responder is not fixed. For example, 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 requests / responses on channel 2) in the same manner.

[0060] Although not shown in Figure 3, the scanning operation can also be performed in a passive scanning manner. In passive scanning, the STA performing the scanning moves between channels and waits for a beacon frame. A beacon frame is one of the management frames defined in IEEE 802.11. It announces the existence of a wireless network and is periodically transmitted so that the STA performing the scanning can find the wireless network and participate in the wireless network. In the BSS, the AP performs the role of periodically transmitting the beacon frame, and in the IBSS, the STAs within the IBSS take turns transmitting the beacon frame. When the STA performing the scanning receives a beacon frame, it stores the information about the BSS included in the beacon frame and moves to another channel, recording the beacon frame information on each channel. The STA receiving the beacon frame stores the BSS-related information included in the received beacon frame and moves to the next channel to perform 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.

[0061] After the STA discovers the network, an authentication process may be performed in step S320. This authentication process may be referred to as the first authentication process to clearly distinguish it from the security setup operation of step S340 described below.

[0062] The authentication process involves the STA sending an authentication request frame to the AP, and the AP responding by sending an authentication response frame to the STA. The authentication frame used for the authentication request / response corresponds to a management frame.

[0063] 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), and a Finite Cyclic Group. These are just some examples of information that may be included in an authentication request / response frame, and may be replaced with other information or include additional information.

[0064] An STA can send an authentication request frame to an AP. The AP can determine whether to grant authentication to the STA based on the information contained in the received authentication request frame. The AP can provide the result of the authentication process to the STA via an authentication response frame.

[0065] After the STA is successfully authenticated, 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.

[0066] For example, the association request frame may include information about various capabilities, a beacon listen interval, a service set identifier (SSID), supported rates, supported channels, an RSN, a mobility domain, supported operating classes, a Traffic Indication Map Broadcast request, interworking service capabilities, etc. For example, 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., an association comeback time), overlapping BSS scan parameters, a TIM broadcast response, a Quality of Service (QoS) map, etc. These are just some examples of information that may be included in a combined request / response frame, and may be replaced by other information or include additional information.

[0067] After the STA successfully joins the network, a security setup process may be performed in step S340. The security setup process in step S340 may be referred to as an authentication process through a Robust Security Network Association (RSNA) request / response, the authentication process in step S320 may be referred to as a first authentication process, and the security setup process in step S340 may also be referred to simply as an authentication process.

[0068] The security setup process of step S340 may include, for example, a process of establishing a private key through a four-way handshaking using an Extensible Authentication Protocol over LAN (EAPOL) frame. Furthermore, the security setup process may be performed according to a security method not defined in the IEEE 802.11 standard.

[0069] FIG. 4 is a diagram for explaining a backoff process to which the present disclosure can be applied.

[0070] In wireless LAN systems, the basic access mechanism of MAC (Medium Access Control) is Carrier Sense Multiple Access with Collision Avoidance (CSMA / CA). The CSMA / CA mechanism, also known as the Distributed Coordination Function (DCF) of the IEEE 802.11 MAC, essentially employs a "listen before talk" access mechanism. According to this type of access mechanism, 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. On the other hand, if the medium is detected to be occupied or busy, 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 before attempting to transmit frames. By applying a random backoff period, multiple STAs are expected to attempt to transmit frames after waiting for different periods of time, thereby minimizing collisions.

[0071] In addition, the IEEE 802.11 MAC protocol provides the 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 that periodically polls all receiving APs and / or STAs to ensure that they receive data frames. In addition, the HCF has the Enhanced Distributed Channel Access (EDCA) and the HCF Controlled Channel Access (HCCA). The EDCA is a contention-based access method for a provider to provide data frames to multiple users, while the HCCA uses a non-contention-based channel access method that utilizes a polling mechanism. In addition, the HCF includes a medium access mechanism to improve the Quality of Service (QoS) of the wireless LAN, and can transmit QoS data in both the Contention Period (CP) and the Contention Free Period (CFP).

[0072] Referring to Fig. 4, an operation based on a random backoff period is described. When a medium that was occupied / busy changes to an idle state, multiple STAs can attempt to transmit data (or frames). To minimize collisions, each STA can select a random backoff count, wait for the corresponding slot time, and then attempt transmission. The random backoff count has a pseudo-random integer value and can be determined as one of the values ​​in the range of 0 to CW. Here, CW is a contention window parameter value. The CW parameter is given an initial value of CWmin, but can take a value doubled in case of transmission failure (e.g., when an ACK for a transmitted frame is not received). When the CW parameter value becomes CWmax, data transmission can be attempted while maintaining the CWmax value until data transmission is successful, and if data transmission is successful, it is reset to the CWmin value. The CW, CWmin, and CWmax values ​​are 2. n It is desirable to set it to -1 (n=0, 1, 2, ...).

[0073] Once the random backoff process begins, 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. When the medium becomes idle, the remaining countdown resumes.

[0074] In the example of FIG. 4, when a packet to be transmitted reaches the MAC of STA3, STA3 can immediately transmit a frame if it confirms that the medium is idle for DIFS. The remaining STAs monitor the medium for occupied / busy states and wait. In the meantime, data to be transmitted may also occur in each of STA1, STA2, and STA5, and each STA can count down the backoff slot according to a random backoff count value selected by each STA after waiting for DIFS if the medium is monitored as idle. Assume that STA2 selects the smallest backoff count value and STA1 selects the largest backoff count value. In other words, 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 counting down and wait while STA2 occupies the medium. When STA2's occupation ends and the medium becomes idle again, STA1 and STA5 wait for DIFS and then resume the backoff count that they had stopped. That is, they can start transmitting frames after counting down the remaining backoff slots equal to the remaining backoff time. Since STA5's remaining backoff time is shorter than STA1's, STA5 starts transmitting frames. While STA2 occupies the medium, STA4 may also have data to transmit. From STA4's perspective, when the medium becomes idle, it waits for DIFS, counts down according to its selected random backoff count value, and then starts transmitting frames. In the example of Figure 4, the remaining backoff time of STA5 coincidentally matches the random backoff count value of STA4, in which 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 can start transmitting frames after the remaining backoff time elapses.

[0075] As in the example of Fig. 4, 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. Additionally, 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 elapses, such as DIFS or PIFS (Point coordination function IFS). Subtype frames of a 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 Request-To-Send (RTS), Clear-To-Send (CTS), Acknowledgment (ACK), Power Save-Poll (PS-Poll), Block ACK (BlockAck), Block ACK Request (BlockACKReq), Null Data Packet Announcement (NDP), and Trigger. If the control frame is not a response frame to the previous frame, it is transmitted after a backoff performed after the DIFS (Direct Inverse Frame Stop) has elapsed, and if it is a response frame to the previous frame, it is transmitted without a backoff performed after the SIFS (short IFS). The type and subtype of the frame can be identified by the type field and subtype field in the Frame Control (FC) field.

[0076] 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, i.e., AIFS[i] (where i is a value determined by the AC), has elapsed. Here, the frames for which AIFS[i] can be used can be data frames, management frames, and also control frames that are not response frames.

[0077] FIG. 5 is a diagram for explaining a CSMA / CA-based frame transmission operation to which the present disclosure can be applied.

[0078] As mentioned above, the CSMA / CA mechanism includes virtual carrier sensing in addition to physical carrier sensing, in which STAs directly sense the medium. Virtual carrier sensing is intended to address potential issues in medium access, such as the hidden node problem. For virtual carrier sensing, the MAC of an STA can utilize a Network Allocation Vector (NAV). The NAV is a value that an STA that is currently using or has the right to use the medium indicates to other STAs the remaining time until the medium becomes available. Therefore, the value set as NAV corresponds to the period during which the STA transmitting the frame is scheduled to use the medium, and an STA receiving the NAV value is prohibited from accessing the medium during that period. For example, the NAV can be set based on the value of the "duration" field in the MAC header of the frame.

[0079] In the example of FIG. 5, it is assumed that STA1 wants to transmit data to STA2, and STA3 is in a position to overhear some or all of the frames transmitted and received between STA1 and STA2.

[0080] In order to reduce the possibility of collisions in transmissions of multiple STAs in a CSMA / CA-based frame transmission operation, a mechanism using RTS / CTS frames may be applied. In the example of FIG. 5, while STA1 is transmitting, STA3 may determine that the medium is idle based on carrier sensing results. That is, STA1 may correspond to a hidden node for STA3. Alternatively, in the example of FIG. 5, while STA2 is transmitting, STA3 may determine that the medium is idle based on carrier sensing results. That is, STA2 may correspond to a hidden node for STA3. By exchanging RTS / CTS frames before performing data transmission and reception between STA1 and STA2, STAs outside the transmission range of either STA1 or STA2, or STAs outside the carrier sensing range for transmissions from STA1 or STA3, may not attempt to occupy the channel during data transmission and reception between STA1 and STA2.

[0081] Specifically, STA1 can determine whether a channel is occupied through carrier sensing. In terms of physical carrier sensing, STA1 can determine channel occupancy idleness based on the energy level or signal correlation detected in the channel. Furthermore, in terms of virtual carrier sensing, STA1 can determine the channel occupancy status using a network allocation vector (NAV) timer.

[0082] STA1 can transmit an RTS frame to STA2 after performing a backoff if the channel is idle during the DIFS. STA2 can transmit a CTS frame, which is a response to the RTS frame, to STA1 after an SIFS if it receives the RTS frame.

[0083] If STA3 cannot overhear a CTS frame from STA2 but can overhear an RTS frame from STA1, STA3 can use the duration information contained in the RTS frame to set a NAV timer for the subsequent consecutively transmitted frame transmission period (e.g., SIFS + CTS frame + SIFS + data frame + SIFS + ACK frame). Alternatively, if STA3 cannot overhear an RTS frame from STA1 but can overhear a CTS frame from STA2, STA3 can use the duration information contained in the CTS frame to set a NAV timer for the subsequent consecutively transmitted frame transmission period (e.g., SIFS + data frame + SIFS + ACK frame). That is, if 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. If STA3 receives a new frame before the NAV timer expires, it can update the NAV timer using the duration information contained in the new frame. STA3 does not attempt channel access until the NAV timer expires.

[0084] If STA1 receives a CTS frame from STA2, it can transmit a data frame to STA2 after SIFS from the time when the CTS frame is completely received. 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 another terminal during the DIFS after the NAV timer expires, it can attempt channel access after a contention window (CW) based on a random backoff has elapsed.

[0085] 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.

[0086] The PHY layer can prepare an MPDU (MAC PDU) to be transmitted based on 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 the information (e.g., data) provided by 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.

[0087] In this way, information transmission / reception in a wireless LAN system is done in the form of frames, and for this purpose, the PHY layer Protocol Data Unit (PPDU) format is defined.

[0088] A basic PPDU may include a Short Training Field (STF), a Long Training Field (LTF), a SIGNAL (SIG) field, and a Data field. The most basic (e.g., non-HT (High Throughput) as illustrated in FIG. 7) PPDU format may consist of only the Legacy-STF (L-STF), Legacy-LTF (L-LTF), Legacy-SIG (L-SIG) fields, and a Data field. Additionally, depending on the type of PPDU format (e.g., HT-mixed format PPDU, HT-greenfield format PPDU, VHT (Very High Throughput) PPDU, etc.), additional (or different types of) RL-SIG, U-SIG, non-legacy SIG field, non-legacy STF, non-legacy LTF, (i.e., xx-SIG, xx-STF, xx-LTF (e.g., xx is HT, VHT, HE, EHT, etc.)) may be included between the L-SIG field and the data field. More specific details will be described later with reference to FIG. 7.

[0089] STF is a signal for signal detection, AGC (Automatic Gain Control), diversity selection, and precise time synchronization, while LTF is a signal for channel estimation, frequency error estimation, etc. STF and LTF can be said to be signals for synchronization and channel estimation of the OFDM physical layer.

[0090] The SIG field may include various information related to PPDU transmission and reception. For example, 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 the modulation and coding rate of data. For example, the 12-bit Length field may include information about the length or time duration of the PPDU. For example, the value of the 12-bit Length field may be determined based on the type of the PPDU. For example, for a non-HT, HT, VHT, or EHT PPDU, the value of the Length field may be determined as a multiple of 3. For example, for HE PPDU, the value of the Length field can be determined as a multiple of 3 + 1 or a multiple of 3 + 2.

[0091] The data field may include a SERVICE field, a Physical layer Service Data Unit (PSDU), a PPDU TAIL bit, and, if necessary, padding bits. Some bits of the SERVICE field may be used to synchronize the descrambler at the receiving end. The PSDU corresponds to a MAC PDU defined at the MAC layer and may contain data generated / used by upper layers. The PPDU TAIL bit may be used to return the encoder to a 0 state. The padding bit may be used to adjust the length of the data field to a predetermined unit.

[0092] MAC PDUs are defined according to various MAC frame formats, and a basic MAC frame consists of a MAC header, a frame body, and a Frame Check Sequence (FCS). A MAC frame is composed of MAC PDUs and can be transmitted / received through the PSDU in the data portion of the PPDU format.

[0093] 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 the receiver address, transmitter address, destination address, and 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.

[0094] The Null-Data PPDU (NDP) format refers to a PPDU format that does not include a data field. In other words, NDP refers to a frame format that includes a PPDU preamble (i.e., L-STF, L-LTF, L-SIG fields, and, if additionally present, non-legacy SIG, non-legacy STF, and non-legacy LTF) in the general PPDU format, and does not include the remaining part (i.e., data field).

[0095] FIG. 7 is a diagram illustrating examples of PPDUs defined in the IEEE 802.11 standard to which the present disclosure can be applied.

[0096] Standards such as IEEE 802.11a / g / n / ac / ax use various PPDU formats. 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 referred to as the non-HT PPDU format (Fig. 7(a)).

[0097] The HT PPDU format (IEEE 802.11n) additionally includes HT-SIG, HT-STF, and HT-LFT(s) fields in addition to the basic PPDU format. The HT PPDU format illustrated in Fig. 7(b) may be referred to as an HT-mixed format. Additionally, an HT-greenfield format PPDU may be defined, which corresponds to a format that does not include L-STF, L-LTF, and L-SIG, but consists of HT-GF-STF, HT-LTF1, HT-SIG, one or more HT-LTF, and Data fields (not illustrated).

[0098] An example of the VHT PPDU format (IEEE 802.11ac) includes VHT SIG-A, VHT-STF, VHT-LTF, and VHT-SIG-B fields in addition to the basic PPDU format (Fig. 7(c)).

[0099] An example of a 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 addition to the basic PPDU format (Fig. 7(d)). Depending on specific examples of the HE PPDU format, some fields may be excluded or their lengths may vary. For example, the HE-SIG-B field is included in the HE PPDU format for multi-users (MUs), but the HE PPDU format for single users (SUs) does not include the HE-SIG-B. In addition, the HE trigger-based (TB) PPDU format does not include the HE-SIG-B, and the length of the HE-STF field may vary to 8us. The 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. For example, RL-SIG can be configured identically to L-SIG. The receiving STA can determine that the received PPDU is a HE PPDU or an EHT PPDU, described later, based on the presence of RL-SIG.

[0100] 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 may include a U (universal)-SIG, an EHT-SIG, an EHT-STF, and an EHT-LTF following the RL-SIG.

[0101] The EHT MU PPDU in FIG. 7(e) corresponds to a PPDU that carries one or more data (or PSDUs) for one or more users. That is, the EHT MU PPDU can be used for both SU transmission and MU transmission. For example, the EHT MU PPDU can correspond to a PPDU for one receiving STA or multiple receiving STAs.

[0102] The EHT TB PPDU of Fig. 7(f) omits the 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)) can perform UL transmission based on the EHT TB PPDU format.

[0103] The L-STF, L-LTF, L-SIG, RL-SIG, U-SIG (Universal SIGNAL), and EHT-SIG fields can be encoded and modulated so that even legacy STAs can attempt demodulation and decoding, and can be mapped based on a predetermined subcarrier frequency interval (e.g., 312.5 kHz). These can be referred to as pre-EHT modulated fields. Next, the EHT-STF, EHT-LTF, Data, and PE fields can be encoded and modulated so that they can be demodulated and decoded by an STA that has successfully decoded a non-legacy SIG (e.g., U-SIG and / or EHT-SIG) and obtained the information contained in the corresponding field, and can be mapped based on a predetermined subcarrier frequency interval (e.g., 78.125 kHz). These can be referred to as EHT modulated fields.

[0104] Similarly, in the HE PPDU format, the L-STF, L-LTF, L-SIG, RL-SIG, HE-SIG-A, and HE-SIG-B fields may be referred to as pre-HE modulation fields, and the HE-STF, HE-LTF, Data, and PE fields may be referred to as HE modulation fields. Additionally, in the VHT PPDU format, the L-STF, L-LTF, L-SIG, and VHT-SIG-A fields may be referred to as pre-VHT modulation fields, and the VHT STF, VHT-LTF, VHT-SIG-B, and Data fields may be referred to as VHT modulation fields.

[0105] 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 4 us, and the U-SIG can have a total duration of 8 us. Each symbol of the U-SIG can be used to transmit 26 bits of information. For example, each symbol of the U-SIG can be transmitted and received based on 52 data tones and 4 pilot tones.

[0106] U-SIGs can be configured in 20MHz units. For example, when an 80MHz PPDU is configured, the same U-SIG can be duplicated 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-SIGs in the first 80MHz unit and the U-SIGs in the second 80MHz unit can be different.

[0107] For example, A uncoded bits may be transmitted via U-SIG, and a first symbol of U-SIG (e.g., a U-SIG-1 symbol) may transmit the first X bits of information out of a total A bits of information, and a second symbol of U-SIG (e.g., a U-SIG-2 symbol) may transmit the remaining Y bits of information out of a total A bits of information. The A bits of information (e.g., 52 uncoded bits) may include a CRC field (e.g., a field of 4 bits in length) and a tail field (e.g., a field of 6 bits in length). The tail field may be used to terminate the trellis of the convolutional decoder and may be set to 0, for example.

[0108] The A bit information transmitted by U-SIG can be divided into version-independent bits and version-dependent bits. For example, U-SIG can 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 can be the same, and some or all of the version-dependent bits can be different.

[0109] For example, 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.

[0110] For example, the version-independent bits of the 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 PPDUs. The version-independent bits of the U-SIG may include a 1-bit UL / DL flag field. The first value of the 1-bit UL / DL flag field relates to UL communication, and the second value of the UL / DL flag field relates to DL communication. The version-independent bits of the U-SIG may include information about the length of a transmission opportunity (TXOP) and information about a BSS color ID.

[0111] For example, the version-dependent bits of the U-SIG may contain information that directly or indirectly indicates the type of PPDU (e.g., SU PPDU, MU PPDU, TB PPDU, etc.).

[0112] Information required for PPDU transmission and reception may be included in the U-SIG. For example, the U-SIG may further include information about bandwidth, information about the MCS technique applied to the non-legacy SIG (e.g., EHT-SIG or UHR-SIG), information indicating whether a dual carrier modulation (DCM) technique (e.g., a technique to achieve 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 across the entire band, etc.

[0113] Some of the information required for transmitting and receiving a PPDU may be included in the U-SIG and / or the non-legacy SIG (e.g., EHT-SIG or UHR-SIG, etc.). For example, information about the type of the 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, information about the guard interval (GI) applicable to the non-legacy LTF, information about preamble puncturing applicable to the PPDU, information about resource unit (RU) allocation, etc. may be included only in the U-SIG, may be included only in the non-legacy SIG, or may be indicated by a combination of the information included in the U-SIG and the information included in the non-legacy SIG.

[0114] Preamble puncturing may refer to the transmission of a PPDU in which no signal is present in one or more frequency units within the PPDU's bandwidth. For example, the size of the frequency unit (or the resolution of the preamble puncturing) may be defined as 20 MHz, 40 MHz, etc. For example, preamble puncturing may be applied to a PPDU bandwidth greater than a certain size.

[0115] In the example of FIG. 7, non-legacy SIGs such as HE-SIG-B and EHT-SIG may include control information for the receiving STA. The non-legacy SIG may be transmitted over at least one symbol, and each symbol may have a length of 4 us. Information regarding the number of symbols used for the EHT-SIG may be included in a previous SIG (e.g., HE-SIG-A, U-SIG, etc.).

[0116] Non-legacy SIGs, such as HE-SIG-B and EHT-SIG, may contain common fields and user-specific fields. Common and user-specific fields may be coded separately.

[0117] In some cases, common fields may be omitted. For example, in a compressed mode where non-OFDMA (orthogonal frequency multiple access) is applied, common fields may be omitted, and multiple STAs may receive PPDUs (e.g., data fields of PPDUs) over the same frequency band. In a non-compressed mode where OFDMA is applied, multiple users may receive PPDUs (e.g., data fields of PPDUs) over different frequency bands.

[0118] The number of user-specific fields can be determined based on the number of users. A single user block field can contain up to two user fields. Each user field can be associated with either MU-MIMO allocation or non-MU-MIMO allocation.

[0119] The common field may include CRC bits and Tail bits, the length of the CRC bits may be determined as 4 bits, and the length of the Tail bits may be determined as 6 bits and 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.

[0120] An RU can contain multiple subcarriers (or tones). RUs can be used when transmitting signals to multiple STAs based on OFDMA techniques. RUs can also be defined when transmitting signals to a single STA. Resources can be allocated on an RU basis for non-legacy STFs, non-legacy LTFs, and data fields.

[0121] Depending on the PPDU bandwidth, an applicable RU size 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.). For example, in the case of an 80MHz PPDU, 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. For example, a tone plan for a wide bandwidth can be defined in the form of multiple repetitions of a low bandwidth tone plan.

[0122] RUs of different sizes can be defined, such as 26-ton RU, 52-ton RU, 106-ton RU, 242-ton RU, 484-ton RU, 996-ton RU, 2X996-ton RU, 3X996-ton RU, etc. A multiple RU (MRU) is distinguished from multiple individual RUs and corresponds to a group of subcarriers consisting of multiple RUs. For example, one MRU can be defined as 52+26-tons, 106+26-tons, 484+242-tons, 996+484-tons, 996+484+242-tons, 2X996+484-tons, 3X996-tons, or 3X996+484-tons. Additionally, multiple RUs constituting one MRU may or may not be consecutive in the frequency domain.

[0123] The specific size of an 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. Furthermore, within a given bandwidth (e.g., 20, 40, 80, 160, 320 MHz, etc.) in the present disclosure, the number of RUs may vary depending on the RU size.

[0124] The names of each field in the PPDU formats of FIG. 7 are exemplary and the scope of the present disclosure is not limited by those names. Furthermore, 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.

[0125] FIG. 8 is a drawing showing an exemplary format of a trigger frame to which the present disclosure can be applied.

[0126] A trigger frame may allocate resources for the transmission of one or more TB PPDUs and request the transmission of TB PPDUs. The trigger frame may also include other information required by the STA transmitting the TB PPDU in response. The trigger frame may include common information and a user information list field in the frame body.

[0127] The common information field may include information that is common to one or more TB PPDU transmissions requested by a 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. Fig. 8 illustrates an example of an EHT variant common information field format.

[0128] The 4-bit trigger type subfield can have values ​​from 0 to 15. Among them, the values ​​0, 1, 2, 3, 4, 5, 6, and 7 of the trigger type subfield are defined to correspond to basic, Beamforming Report Poll (BFRP), multi user-block acknowledgement request (MU-BAR), multi user-request to send (MU-RTS), Buffer Status Report Poll (BSRP), groupcast with retries (GCR), MU-BAR, Bandwidth Query Report Poll (BQRP), and NDP Feedback Report Poll (NFRP), respectively, and the values ​​8 to 15 are defined as reserved.

[0129] Among the common information, the trigger dependent common info subfield may include information that is optionally included based on the trigger type.

[0130] 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 extended common information not provided in the common information field.

[0131] A user information list contains zero or more user information fields. Figure 8 illustrates an example of an EHT variant user information field format.

[0132] The AID12 subfield basically indicates that it is a user information field for an STA with the corresponding AID. In addition, if 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 information field. The special user information field is a user information field that does not contain user-specific information, but contains extended common information not provided in the common information field. For example, the special user information field can be identified by the AID12 value of 2007, and the special user information field flag subfield within the common information field can indicate whether the special user information field is included.

[0133] The RU allocation subfield can indicate the size and location of an RU / MRU. For this purpose, the RU allocation subfield can be interpreted together with the PS160 (primary / secondary 160MHz) subfield of the user information field, the UL BW subfield of the common information field, etc.

[0134] A method for transmitting and receiving delayed private traffic in an improved wireless LAN system.

[0135] Broader frequency bandwidth allocation and the resulting advancements in transmission technology are increasingly supporting services and applications requiring low-latency communications. For example, augmented reality (AR) technology is being widely utilized for XR (eXtended Reality) devices, which require low-latency communications.

[0136] For example, data / traffic requiring low latency (e.g., delay-sensitive data / traffic or / and transmission delay data / traffic) has a requirement for a pre-given / defined transmission delay. The scheduling algorithm currently used in WLAN systems can utilize information about the amount of data that STA(s) are waiting (queued) or storing in a buffer for transmission. If the scheduler is provided with information about the amount of data waiting / stored in a buffer and the urgency of the transmission delay requirement for the data, the scheduler can process the transmission delay data more efficiently. The data can be designated by AC (Access Category), UP (User Priority), TID (Traffic Identifier), etc.

[0137] The restricted (R) target wake time (TWT) feature introduced / defined in IEEE 802.11be-based (e.g., EHT-based) wireless LAN systems can enable low-latency transmission by including STA(s) in the SP (service period).

[0138] Here, TWT is a PS (Power Saving) technology that can improve the energy efficiency of non-AP STAs by defining SPs between APs and non-AP STAs and sharing information about SPs to reduce media contention. That is, STAs and APs can negotiate the time to send and receive data, and STAs can be activated only when data transmission and reception is required, and doze off the rest of the time, thereby reducing battery consumption.

[0139] R-TWT can support securing data transmission availability for low-latency STAs that transmit latency-sensitive data preferentially over other STAs by having the AP configure a special broadcast TWT for the low-latency STA. An STA can establish membership in one or more R-TWT schedules with the AP.

[0140] Here, the R-TWT agreement can be established by the same process as the broadcast TWT agreement, and the broadcast TWT element for this can be defined to include an r-TWT parameter set field. For example, the r-TWT parameter set can refer to a specific broadcast TWT parameter set field that is distinct from other broadcast TWT parameter set fields. In other words, the r-TWT parameter set field can correspond to a special case of the broadcast TWT parameter set field. In addition, the AP can announce the R-TWT SP.

[0141] Membership in R-TWT refers to the process by which a specific STA acquires and manages the right to participate in and use an R-TWT service (SP) reserved by an AP. When an STA joins / participates as a "member" in an R-TWT service (SP) set by an AP, the STA is granted exclusive channel access during that service. Other STAs that have not joined the membership may have their channel access restricted or prohibited during that service.

[0142] When one or more STAs requiring low latency are included in the same R-TWT SP, transmission support may be required depending on the delay bound that each STA(s) must meet (e.g., the maximum delay time that may occur during data / traffic processing).

[0143] Below, a method for supporting uplink transmission according to delay bound is described when one or more STAs are assigned to and operate in R-TWT SP membership.

[0144] As an example, a method for supporting uplink transmission in cases where the delay bounds and traffic identification (TID) of STA(s) are the same and different is described. In addition, a method utilizing the exchange of various frames (e.g., a BSRP (buffer status report poll) (trigger) frame and a frame containing a BSR (buffer status report), etc.) and a method for piggybacking transmission time-related information when transmitting QoS data are described.

[0145] In describing the present disclosure, one or more STAs (MLDs) may be assigned to a membership associated with the same R-TWT SP. STAs (MLDs) assigned to the same membership may have the same delay bound and / or TID.

[0146] At the initiation time of the R-TWT SP, the AP (MLD) may request / request information about the amount / size of data to be processed / transmitted within the delay bound to the STA (MLD)(s) based on the traffic request information (e.g., TID information, etc.) of each STA (MLD)(s). That is, the AP (MLD) may transmit a frame requesting / requesting the amount / size of data to be processed / transmitted within the delay bound to the STA (MLD) using a solicited method.

[0147] STA(s) that receive the request / request may transmit information on the amount / size of data to be processed within a delay time (e.g., delay bound) specified by the AP (MLD) to the AP (MLD). The AP (MLD) may transmit a (RU(resource unit)) trigger frame to the STA (MLD) for allocating resources to support transmission of the STA (MLD)(s) based on the information related to the amount / size of data received from the STA (MLD)(s). The STA (MLD)(s) may transmit low-latency data (e.g., delay-sensitive traffic, etc.) to the AP (MLD) by using the resources allocated by the received trigger frame so as to satisfy the delay bound (e.g., conditions related to data transmission within the delay bound, etc.).

[0148] As an example of the present disclosure, assume that one or more STAs (MLDs) request different delay bounds. The AP (MLD) may specify one or more delay bounds and request information about the amount / size of data to be processed within the specified one or more delay bounds from one or more STAs (MLDs). In this case, the delay bound information may be mapped to a TID.

[0149] After receiving information on the amount / size of data to be processed within a delay bound from the STA (MLD)(s), the AP (MLD) can instruct / request single-user (SU) or multi-user (MU) transmission to the STA (MLD) using a trigger frame. The AP (MLD) can receive data (e.g., delay-sensitive traffic, etc.) from the STA (MLD) based on the trigger frame. The AP (MLD) can transmit information related to whether the data transmitted by the STA MLD(s) was received to the STA MLD(s) through MU-BA (multi-user Block Acknowledgement) or BA.

[0150] As an example of the present disclosure, STA (MLD)(s) assigned to R-TWT SP membership may include information on the amount / size of low-latency data (e.g., delay-sensitive traffic) that needs to be transmitted within a certain period of time in the QoS data when transmitting the QoS data. After receiving the information on the amount / size of the low-latency data, the AP (MLD) may transmit a trigger frame to the STA (MLD)(s) based on the urgency. The STA (MLD)(s) may transmit data (e.g., delay-sensitive traffic) (within a delay bound) based on the tripper frame.

[0151] Meanwhile, the STA (AP STA and / or non-AP STA) described in the present disclosure may support multi-link (ML) communication. ML communication may refer to communication that supports multiple links. Links related to ML communication may include channels (e.g., 20 / 40 / 80 / 160 / 240 / 320MHz channels) of a frequency band (e.g., 2.4GHz band, 5GHz band, 6GHz band, etc.) in which the STA operates. The multiple links used for ML communication may be configured in various ways. For example, the multiple links supported for one STA for ML communication may belong to the same frequency band or may belong to different frequency bands. In addition, each link may correspond to a frequency unit of a predetermined size (e.g., a channel, a subchannel, an RU, etc.). In addition, some or all of the multiple links may be frequency units of the same size or may be frequency units of different sizes.

[0152] When one STA supports multiple links, the transmitting and receiving devices supporting each link can operate as one logical STA. That is, an MLD is a device that has one or more affiliated STAs as a logical entity and a single MAC service access point (SAP) for one MAC data service and logical link control (LLC). A non-AP MLD refers to an MLD in which each STA affiliated with the MLD is a non-AP STA. A multi-radio non-AP MLD refers to a non-AP MLD that supports receiving or exchanging frames on more than one link at a time. An AP MLD refers to an MLD in which each STA affiliated with the MLD is an AP STA.

[0153] Multi-link operation (MLO) can enable a non-AP MLD to discover, authenticate, associate, and set up multiple links with an AP MLD. Based on the supported capabilities exchanged during the association procedure, each link can enable channel access and frame exchange between the non-AP MLD and the AP MLD. An STA affiliated with an MLD can select and manage its capabilities and operating parameters independently from other STA(s) affiliated with the same MLD.

[0154] FIG. 9 is a diagram illustrating the operation of a first STA according to one embodiment of the present disclosure. Here, the first STA may belong to a first non-AP MLD, and the operation of the first STA described with reference to FIG. 9 may be expressed as the operation of the first non-AP MLD. In other words, FIG. 9 may also be interpreted as the operation of the first non-AP MLD to which the first STA belongs.

[0155] A first STA may receive a first trigger frame including at least one delay bound from a first AP (S910). Here, the first AP may belong to an AP MLD, and the operation of the first AP may be expressed as the operation of the AP MLD. That is, the first STA (e.g., the first non-AP MLD) may receive the first trigger frame from the AP MLD.

[0156] For example, the first trigger frame may include a buffer status report poll (BSRP) trigger frame or a trigger frame associated with a request for information related to delay-sensitive traffic (e.g., a low latency (LL) BSRP trigger frame). If the first trigger frame is an LL BSRP trigger frame, the value of the trigger type subfield of the first trigger frame may be set to one of 9 to 15.

[0157] For example, the first trigger frame may include at least one of a first field related to a request for first information or a second field related to a reference point in time.

[0158] For example, if the first field value is set to 1 (or 0), this may mean that the first trigger frame requests the size (or amount) of traffic to be transmitted within at least one delay bound. In addition, the reference point in time may include at least one of the transmission start point, the reception start point, the transmission completion point, or the reception completion point of the first trigger frame.

[0159] The first STA may transmit a first frame containing first information related to the size of first delay-sensitive traffic to be transmitted within at least one delay bound to the first AP (S920). In describing the present disclosure, delay-sensitive traffic may be expressed as low-latency data (or traffic) or traffic (or data). This may be indicated using AC (Access Category), UP (User Priority), TID (Traffic Identifier), etc.

[0160] Specifically, based on receiving the first trigger frame, the first STA can identify whether there is first delay-sensitive traffic that needs to be transmitted up to at least one delay bound from the reference time. If there is first delay-sensitive traffic that needs to be transmitted up to at least one delay bound from the reference time, the first STA can transmit a first frame containing first information including the size (or amount) of the first delay-sensitive traffic to the first AP.

[0161] The first STA may receive a second trigger frame including second information related to a first resource unit for first delay-sensitive traffic from the first AP (S930).

[0162] For example, information related to a first resource unit may be determined based on the size of the first delay-sensitive traffic. The information related to the first resource unit may include, but is not limited to, at least one of the size of the first resource unit (e.g., the number and / or size of the first resource unit) or the time period of the first resource unit.

[0163] For example, the size of the unit of the first resource allocated by the first trigger frame may be determined based on the size of the first delay-sensitive traffic. The larger the number of first delay-sensitive traffics, the larger the unit of the first resource allocated by the first trigger frame.

[0164] The first STA can transmit a second frame containing the first delay-sensitive traffic to the first AP based on the second trigger frame (S940).

[0165] The first STA may transmit a second frame including the first delay-sensitive traffic within at least one delay bound based on the first resource unit allocated by the second trigger frame. Having identified / decoded at least one delay bound through the first trigger frame, the first STA may transmit the second frame to the first AP based on the first resource unit within at least one delay bound (based on the reference time).

[0166] For example, the time period during which the first STA transmits the second frame may be included within a restricted target wake time (R-TWT) service period (SP). That is, the first STA may transmit the second frame to the first AP within a time period that does not exceed at least one delay bound within the R-TWT SP. In addition, the first STA may receive an MU BA frame or a BA frame related to whether the second frame is received from the first AP.

[0167] Additionally or alternatively, the first trigger frame may be transmitted to a second STA as well as the first STA. In this case, the second STA may belong to the first non-AP MLD, similar to the first STA, but is not limited thereto. The second STA may also be transmitted to the second non-AP MLD.

[0168] For example, each of the first STA and the second STA may be assigned to the same R-TWT membership or different R-TWT memberships. In addition, based on the fact that a traffic identifier (TID) mapped to the first delay-sensitive traffic and a TID mapped to the second delay-sensitive traffic (e.g., delay-sensitive traffic to be transmitted by the second STA) are the same, the first trigger frame may include a single delay bound. Based on the fact that the TID mapped to the first delay-sensitive traffic and the TID mapped to the second delay-sensitive traffic are different, the first trigger frame may include multiple delay bounds.

[0169] Additionally or alternatively, the first STA may transmit second information related to the urgency of the first delay-sensitive traffic to the first AP. The third field containing the second information may be included in the first frame or the third frame. The third field containing the second information may indicate whether the transmission of the first delay-sensitive traffic is urgent.

[0170] For example, based on the inclusion of the second information in the third frame, the first frame can be transmitted to the first AP after the transmission of the third frame. That is, the first STA can notify the first AP of the urgency of transmitting the first delay-sensitive traffic through the third frame, and then notify the first AP of the size of the first delay-sensitive traffic through the second frame.

[0171] For example, based on the second information indicating that the first delay-sensitive traffic is urgent being transmitted to the first AP, the first delay-sensitive traffic may be transmitted to the first AP with priority over delay-sensitive traffic of another STA (e.g., the second STA). For example, the size of the first resource unit allocated by the first trigger frame may be larger than the size of the second resource unit allocated by the second trigger frame. Additionally or alternatively, the time point of the first resource unit allocated by the first trigger frame may be earlier than the time point of the second resource unit allocated by the second trigger frame.

[0172] The method performed by the first STA described in the example of FIG. 9 may be performed by the first device (100) of FIG. 1. For example, one or more processors (102) of the first device (100) of FIG. 1 may receive a first trigger frame including at least one delay bound from a first AP via one or more transceivers (106). The one or more processors (102) may transmit, to the first AP via one or more transceivers (106), a first frame including first information related to a size of first delay-sensitive traffic to be transmitted within the at least one delay bound. The one or more processors (102) may receive, from the first AP via one or more transceivers (106), a second trigger frame including second information related to a first resource unit for the first delay-sensitive traffic. One or more processors (102) can transmit a second frame containing first delay-sensitive traffic to the first AP via one or more transceivers (106) based on the second trigger frame.

[0173] The above memory (104) can store instructions for performing the method described in the example of FIG. 9 when executed by one or more processors (102).

[0174] FIG. 10 is a diagram illustrating the operation of a first AP according to one embodiment of the present disclosure. As described above, the first AP may belong to an AP MLD, and the operation of the first AP may be expressed as the operation of the AP MLD.

[0175] The first AP can transmit a first trigger frame including at least one delay bound to the first STA (S1010).

[0176] For example, the first AP can transmit the first trigger frame not only to the first STA (or, the first non-AP MLD to which the first STA belongs) but also to other STA(s) (e.g., the second STA). The other STA(s) may belong to the first non-AP MLD, but may also belong to other non-AP MLDs. That is, the first AP can transmit the first trigger frame to at least one STA (MLD) that includes the first STA (MLD).

[0177] For example, if the delay-sensitive traffic of the first STA and the second STA have different TIDs mapped thereto, the first AP may transmit a first trigger frame including multiple delay bounds to the first STA and the second STA. The configuration of the first trigger frame has been described with reference to FIG. 9, and thus, a duplicate description will be omitted.

[0178] The first AP may receive a first frame from the first STA, which includes first information related to the size of first delay-sensitive traffic to be transmitted within at least one delay bound (S1020).

[0179] Additionally or alternatively, the first AP may receive the size of the second delay-sensitive traffic to be transmitted by the second STA within at least one delay bound through a frame transmitted by the second STA. Each of the first frame transmitted by the first STA and the frame transmitted by the second STA may include an urgency for transmitting the delay-sensitive traffic.

[0180] The first AP may receive a second trigger frame from the first AP, which includes second information related to the first resource unit for the first delay-sensitive traffic (S1030). For example, the first AP may determine the size and / or time of the resource unit to be allocated to each of the first STA and / or the second STA based on the size of the first delay-sensitive traffic and / or the size of the second delay-sensitive traffic.

[0181] For example, a first AP may allocate a first resource unit to a first STA and a second resource unit to a second STA via a second trigger frame. That is, the first AP may transmit the second trigger frame to at least one STA including the first STA. In this case, the first resource unit and the second resource unit may be allocated within the same time period, but are not limited thereto.

[0182] The first AP may receive a second frame containing first delay-sensitive traffic from the first STA based on the second trigger frame (S1040). For example, the first AP may receive the first delay-sensitive traffic from the first STA based on the first resource unit up to at least one delay bound (based on the reference time).

[0183] The method performed by the first AP described in the example of FIG. 10 may be performed by the second device (200) of FIG. 1. For example, one or more processors (202) of the second device (200) of FIG. 10 may transmit a first trigger frame including at least one delay bound to a first STA via one or more transceivers (106). The one or more processors (102) may receive, from the first STA via one or more transceivers (106), a first frame including first information related to a size of first delay-sensitive traffic to be transmitted within the at least one delay bound. The one or more processors (102) may receive, from the first AP via one or more transceivers (106), a second trigger frame including second information related to a first resource unit for the first delay-sensitive traffic. One or more processors (102) may receive a second frame containing first delay-sensitive traffic from a first STA through one or more transceivers (106) based on a second trigger frame.

[0184] Furthermore, one or more memories (204) of the second device (200) may store instructions for performing the method described in the example of FIG. 10 when executed by one or more processors (202).

[0185] Hereinafter, a delay-sensitive traffic transmission and reception operation method according to the present disclosure will be specifically described.

[0186] Example 1

[0187] Embodiment 1 relates to a method for exchanging information about the amount / size of low-latency traffic (e.g., delay-sensitive traffic) to be transmitted within a delay bound.

[0188] As an example of the present disclosure, information related to the amount / size (or buffer status) of low-latency traffic to be transmitted based on a delay bound may be transmitted and received via various types of frames. For example, the frames may include a BSRP (trigger) frame or / and a BSR frame.

[0189] For example, a BSRP (trigger) frame may include information indicating that the frame requires a buffer state related to low latency (LL) traffic (or delay-sensitive traffic) (e.g., information indicating that the frame is an LL-BSRP (trigger) frame). For example, the (trigger) type subfield value of the LL-BSRP (trigger) frame may be one of 9 to 15.

[0190] For example, the LL-BSRP (trigger) frame, the LL-BSR (prime) or / and the LL traffic frame may include time information for calculating the BSR value of the membership STA(s) of the R-TWT SP (e.g., the STA(s) that have joined the membership).

[0191] STA (MLD)(s) can calculate the amount of data to be transmitted as BSR based on the time / point in time information indicated by the LL-BSRP (trigger) frame. The (reference) time / point in time indicated by the LL-BSRP (trigger) frame may include the start time of transmission of the LL-BSRP (trigger) frame of the AP (MLD) (for calculating the amount of data), the completion time of transmission, the start time of reception (of the LL-BSRP (trigger) frame) of STA (MLD) and / or the completion time of reception. STA (MLD)(s) can calculate the amount of data to be transmitted within a delay bound from the time / point in time indicated by the LL-BSRP (trigger) frame.

[0192] And, the STA (MLD)(s) that received the LL-BSRP (trigger) frame can transmit the amount / size of LL traffic to be transmitted to the AP (MLD) through BSR. For example, the STA (MLD)(s) can transmit the amount / size of the corresponding LL traffic to the AP (MLD) through the LL-BSR frame.

[0193] As an example of the present disclosure, if the TIDs of the R-TWT SP membership STA(s) are different, the LL-BSRP (trigger) frame may include one or more (reference) time / point information. If the TIDs of the R-TWT SP membership STA(s) are the same, the LL-BSRP (trigger) frame may include one (reference) time / point information.

[0194] After receiving an LL-BSR frame from the STA (MLD)(s), the AP (MLD) can determine the required resources of the STA (MLD)(s), which are members that will perform a transmission operation within the R-TWT SP. The AP (MLD) can transmit a trigger frame indicating the determined resources to the STA (MLD)(s). The frame including the LL traffic transmitted by the STA (s) can be configured in the form of a SU or MU frame. The required resources of the STA (MLD)(s) (e.g., the resources required for the STA (MLD)(s) to transmit the LL traffic) can include one or more RUs, etc. determined based on the information included in the LL-BSR frame.

[0195] For example, LL traffic can be transmitted to the AP (MLD) via resources indicated / allocated by a trigger frame. The AP (MLD) can transmit a BA (e.g., MU-BA, etc.) containing information about the reception status and / or reception of the LL traffic to the STA (MLD).

[0196] Example 1-1

[0197] Example 1-1 is a diagram illustrating a procedure for transmitting and receiving LL traffic within a delay bound. FIGS. 11, 12, and 13 are diagrams illustrating a procedure for transmitting and receiving LL traffic within a delay bound according to one embodiment of the present disclosure.

[0198] As an example of the present disclosure, FIG. 11(a) and FIG. 12 relate to a case where R-TWT SP membership STA(s) have the same TID with the same delay bound set. That is, STA (MLD)(s) (e.g., STA (MLD) 1 and STA (MLD) 2) may have the same TID and / or the same delay bound associated with R-TWT SP membership.

[0199] As illustrated in (a) and (b) of FIG. 11 and FIG. 12, the AP (MLD) may transmit an LL-BSRP (trigger) frame including one delay bound value to the STA (MLD)(s) (e.g., STA (MLD) 1 and STA (MLD) 2). The STA (MLD)(s) may transmit the amount of LL traffic to be transmitted up to the delay bound to the AP (MLD) through the LL-BSR frame based on the reference point / time associated with the LL-BSRP (trigger) frame. The reference point / time associated with the LL-BSRP (trigger) frame may be, but is not limited to, the start / completion point of transmission or reception of the LL-BSRP (trigger) frame.

[0200] Accordingly, the AP (MLD) may transmit a trigger frame to the STA (MLD)(s) for allocating resources for transmission of LL traffic based on the LL-BSR frame. For example, as illustrated in FIG. 12, if the amount of data to be processed / transmitted by STA (MLD) 1 up to the delay bound is greater than the amount of data to be processed / transmitted by STA (MLD) 2 up to the delay bound, the amount of resources (e.g., RUs) allocated to the first STA (MLD) by the trigger frame may be greater than the amount of resources (e.g., RUs) allocated to the second STA (MLD) by the trigger frame.

[0201] Accordingly, STA (MLD)(s) (e.g., STA (MLD) 1 and STA (MLD) 2) may transmit frames containing LL traffic (e.g., QoS data) to AP (MLD) based on trigger frames within delay bounds. AP (MLD) may transmit MU-BA containing information related to whether LL traffic is received to STA (MLD)(s).

[0202] As an example of the present disclosure, FIG. 11(b) and FIG. 13 relate to a case where R-TWT SP membership STA(s) have different delay bounds and different TIDs. That is, STA (MLD)(s) (e.g., STA (MLD) 1 and STA (MLD) 2) may have different TIDs and / or delay bounds associated with R-TWT SP membership.

[0203] For example, as illustrated in (b) of FIG. 11 and FIG. 13, an AP (MLD) may transmit an LL-BSRP (trigger) frame containing multiple delay bound values ​​(e.g., two delay bound values) to STA (MLD)(s) (e.g., STA (MLD) 1 and STA (MLD) 2).

[0204] STA (MLD)(s) may transmit to AP (MLD) via LL-BSR frame the amount of LL traffic to be transmitted up to the delay bound based on the reference point / time associated with the LL-BSRP (trigger) frame. The reference point / time associated with the LL-BSRP (trigger) frame may be, but is not limited to, the initiation / completion point of transmission or reception of the LL-BSRP (trigger) frame.

[0205] Accordingly, the AP (MLD) may transmit a trigger frame to the STA (MLD)(s) for allocating resources for transmission of LL traffic based on the LL-BSR frame. For example, as illustrated in FIG. 13, if the amount of data to be processed / transmitted by STA (MLD) 1 up to the delay bound is greater than the amount of data to be processed / transmitted by STA (MLD) 2 up to the delay bound, the amount of resources (e.g., RUs) allocated to STA (MLD) 1 by the trigger frame may be greater than the amount of resources (e.g., RUs) allocated to STA (MLD) 2 by the trigger frame.

[0206] Additionally or alternatively, the urgency of traffic transmission of STA (MLD) 1 may be higher than the urgency of traffic transmission of STA (MLD) 2. For example, the delay bound value of STA (MLD) 1 may be smaller than the delay bound value of STA (MLD) 2, and thus, data transmission of STA (MLD) 1 may need to be performed with priority. However, this is only one embodiment, and as described in Embodiment 2, if STA (MLD) 1 transmits the presence or absence of data requiring urgency to AP (MLD), the urgency of traffic transmission of STA (MLD) 1 may be higher.

[0207] Accordingly, STA (MLD)(s) (e.g., STA (MLD) 1 and STA (MLD) 2) may transmit frames containing LL traffic (e.g., QoS data) to AP (MLD) based on trigger frames within delay bounds. AP (MLD) may transmit MU-BA containing information related to whether LL traffic is received to STA (MLD)(s).

[0208] Additionally, the AP (MLD) may transmit an additional trigger frame to the STA (MLD) 2 that has not transmitted all of the LL traffic. The STA (MLD) 2 may transmit a frame containing LL traffic (e.g., QoS data) to the AP (MLD) based on the additional trigger frame within its delay bound. The AP (MLD) may transmit a BA containing information regarding whether the LL traffic has been received to the STA (MLD) 2.

[0209] Example 2

[0210] Example 2 relates to a method for indicating the urgency of data transmission (e.g., data imminent to delay bound).

[0211] STA (MLD)(s) assigned to R-TWT SP membership can notify AP (MLD) that there is data requiring urgency (e.g., LL traffic). That is, STA (MLD)(s) can transmit information indicating whether there is data requiring urgency to AP (MLD). For example, if the field value in which the above information is set is set to 0 (or 1), this may mean that STA (MLD)(s) do not have urgent data. If the field value in which the above information is set is set to 1 (or 0), this may mean that STA (MLD)(s) have urgent data.

[0212] For example, when STA (MLD)(s) have urgent data, data exchange may be performed between AP (MLD) and STA (MLD)(s) to confirm the amount / size of the urgent data. For example, STA (MLD)(s) may transmit a frame containing the amount / size of the urgent data to AP (MLD) (at AP (MLD) request).

[0213] Additionally or alternatively, the STA (MLD)(s) may transmit to the AP (MLD) information about the presence of data requiring urgency and the amount / size of the data. For example, the STA (MLD)(s) may transmit to the AP (MLD) information about the presence of data requiring urgency and the amount / size of the data via a BSR frame (e.g., an LL-BSR frame). In addition to the amount / size of the data, the STA (MLD) may transmit to the AP (MLD) characteristics of the data (e.g., the degree of urgency, etc.).

[0214] The AP (MLD) may transmit a trigger frame to the STA (MLD)(s) immediately or after a certain period of time after receiving information about the presence of data requiring urgency and / or the amount / size of the data (depending on the urgency of the data). The trigger frame may request transmission of the data. The STA (MLD) may transmit the data to the AP (MLD) using the resources allocated by the trigger frame.

[0215] Example 2-1

[0216] Example 2-1 is a diagram illustrating a procedure for transmitting and receiving LL traffic within a delay bound. FIGS. 14, 15, and 16 are diagrams illustrating a procedure for transmitting and receiving LL traffic within a delay bound according to one embodiment of the present disclosure.

[0217] As an example of the present disclosure, FIG. 14(a) and FIG. 15 relate to a case where R-TWT SP membership STA(s) have the same TID with the same delay bound set. That is, STA (MLD)(s) (e.g., STA (MLD) 1 and STA (MLD) 2) may have the same TID and / or the same delay bound associated with R-TWT SP membership.

[0218] As illustrated in (a) of FIG. 14 and FIG. 15, STA (MLD)(s) (e.g., STA (MLD) 1 and STA (MLD) 2) may transmit QoS data (e.g., LL-BSR information) to the AP (MLD). For example, the LL-BSR information may include information about the presence of data requiring urgency and / or the amount / size of the data and / or the level of urgency.

[0219] Accordingly, the AP (MLD) may transmit a trigger frame to the STA (MLD)(s) for allocating resources for transmission of LL traffic. For example, as illustrated in FIG. 15, if the amount of data to be processed / transmitted by STA (MLD) 1 up to the delay bound is greater than the amount of data to be processed / transmitted by STA (MLD) 2 up to the delay bound, the amount of resources (e.g., RUs) allocated to the first STA (MLD) by the trigger frame may be greater than the amount of resources (e.g., RUs) allocated to the second STA (MLD) by the trigger frame.

[0220] Accordingly, STA (MLD)(s) (e.g., STA (MLD) 1 and STA (MLD) 2) may transmit frames containing LL traffic (e.g., QoS data) to AP (MLD) based on trigger frames within delay bounds. AP (MLD) may transmit MU-BA containing information related to whether LL traffic is received to STA (MLD)(s).

[0221] As an example of the present disclosure, FIG. 14(b) and FIG. 15 relate to a case where R-TWT SP membership STA(s) have different delay bounds and different TIDs. That is, STA (MLD)(s) (e.g., STA (MLD) 1 and STA (MLD) 2) may have different TIDs and / or delay bounds associated with R-TWT SP membership.

[0222] For example, as illustrated in (b) of FIG. 14 and FIG. 15, STA (MLD)(s) (e.g., STA (MLD) 1 and STA (MLD) 2) may transmit QoS data (e.g., LL-BSR information) to the AP (MLD). For example, the LL-BSR information may include information about the presence of data requiring urgency and / or the amount / size of the data. In the following, it is assumed that the LL traffic transmission of STA (MLD) 1 is urgent.

[0223] STA (MLD)(s) may transmit to AP (MLD) via LL-BSR frame the amount of LL traffic to be transmitted up to the delay bound based on the reference point / time associated with the LL-BSRP (trigger) frame. The reference point / time associated with the LL-BSRP (trigger) frame may be, but is not limited to, the initiation / completion point of transmission or reception of the LL-BSRP (trigger) frame.

[0224] Accordingly, the AP (MLD) may transmit a trigger frame to the STA (MLD)(s) for allocating resources for transmission of LL traffic based on the LL-BSR frame. For example, as illustrated in FIG. 15, if the amount of data to be processed / transmitted by STA (MLD) 1 up to the delay bound is greater than the amount of data to be processed / transmitted by STA (MLD) 2 up to the delay bound, the amount of resources (e.g., RUs) allocated to STA (MLD) 1 by the trigger frame may be greater than the amount of resources (e.g., RUs) allocated to STA (MLD) 2 by the trigger frame.

[0225] Additionally or alternatively, as described above, the urgency of traffic transmission of STA (MLD) 1 may be higher than the urgency of traffic transmission of STA (MLD) 2. Accordingly, the STA (MLD)(s) (e.g., STA (MLD) 1 and STA (MLD) 2) may transmit frames containing LL traffic (e.g., QoS data) to the AP (MLD) based on a trigger frame within a delay bound. The AP (MLD) may transmit an MU-BA containing information related to whether or not the LL traffic is received to the STA (MLD)(s). In this case, the LL traffic transmission of STA (MLD) 1 may be performed preferentially.

[0226] Additionally, after STA (MLD) 1 completes transmitting LL traffic, AP (MLD) may transmit an additional trigger frame to STA (MLD) 2, which has not yet transmitted all of its LL traffic. STA (MLD) 2 may transmit a frame containing LL traffic (e.g., QoS data) to AP (MLD) based on the additional trigger frame within its delay bound. AP (MLD) may transmit a BA containing information related to whether LL traffic was received to STA (MLD) 2.

[0227] Various embodiments of the present disclosure enable efficient support of services / applications using low-latency communication across multiple devices. Furthermore, various embodiments of the present disclosure enable efficient transmission and reception of not only the amount of low-latency data to be transmitted, but also the urgency of the data.

[0228] The various examples of the present disclosure can be extended to multi-link operations. For example, when multi-links are set up, the STA (MLD) can transmit data to be transmitted within a delay bound and / or the urgency of the data to the AP (MLD) along with link information. The link information may include identification information for the link through which the data will be transmitted.

[0229] The embodiments described above are combinations of components and features of the present disclosure in a predetermined form. Each component or feature should be considered optional unless explicitly stated otherwise. Each component or feature may be implemented without being combined with other components or features. Furthermore, it is also possible to form embodiments of the present disclosure by combining some components and / or features. The order of operations described in the embodiments of the present disclosure may be changed. Some components or features of one embodiment may be included in another embodiment or may be replaced with corresponding components or features of another embodiment. It is self-evident that claims that do not have an explicit citation relationship in the patent claims may be combined to form embodiments or incorporated as new claims through post-application amendments.

[0230] It will be apparent to those skilled in the art that the present disclosure may be embodied in other specific forms without departing from the essential characteristics of the present disclosure. Therefore, the above detailed description should not be construed as limiting in any respect, but rather as illustrative. The scope of the present disclosure should be determined by a reasonable interpretation of the appended claims, and all modifications within the scope of equivalents of the present disclosure are intended to be included within the scope of the present disclosure.

[0231] 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 methods of 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 comprise a non-transitory computer-readable storage medium. The features described in this disclosure may be incorporated into software and / or firmware stored on any of the machine-readable media, which may control the hardware of the processing system and 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.

[0232] 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.

Claims

1. A method performed by a first non-access point (AP) multi-link device (MLD), the method comprising: A step of receiving a first trigger frame including at least one delay bound from a first AP by a first STA affiliated to the first non-AP MLD; A step of transmitting, by the first STA, to the first AP a first frame including first information related to a size of first delay sensitive traffic to be transmitted within the at least one delay bound; A step of receiving, by the first STA, from the first AP a second trigger frame including second information related to a first resource unit for the first delay-sensitive traffic; and A method comprising the step of transmitting a second frame including the first delay-sensitive traffic to the first AP by the first STA based on the second trigger frame.

2. In paragraph 1, A method wherein the first trigger frame comprises a buffer status report poll (BSRP) trigger frame or a trigger frame related to a request for information related to delay-sensitive traffic.

3. In paragraph 1, The first information includes the size of the first delay-sensitive traffic to be transmitted by the first STA up to the at least one delay bound based on a reference point in time, The above reference point is a method related to the transmission or reception point of the first trigger frame.

4. In paragraph 3, A method wherein the first trigger frame includes at least one of a first field related to a request for the first information or a second field related to the reference point in time.

5. In paragraph 1, A method in which the second frame is transmitted from the first STA to the first AP based on the first resource unit within a restricted target wake time (R-TWT) service period (SP).

6. In paragraph 1, Information related to the first resource unit is determined based on the size of the first delay-sensitive traffic, A method wherein the information related to the first resource unit includes at least one of the size of the first resource unit or the time period of the first resource unit.

7. In paragraph 1, A second resource unit is allocated to a second STA having second delay-sensitive traffic by the second trigger frame, The first resource unit and the second resource unit are allocated within the same time period, A method wherein each of the first STA and the second STA is assigned to the same R-TWT membership or different R-TWT memberships.

8. In paragraph 7, Based on the fact that the traffic identifier (TID) mapped to the first delay-sensitive traffic and the TID mapped to the second delay-sensitive traffic are the same, the first trigger frame includes a single delay bound, A method wherein the first trigger frame includes a plurality of delay bounds based on the difference between the TID mapped to the first delay-sensitive traffic and the TID mapped to the second delay-sensitive traffic.

9. In paragraph 1, A method in which second information related to the urgency of the first delay-sensitive traffic is transmitted from the first STA to the first AP.

10. In paragraph 9, The third field in which the second information is set is included in the first frame or the third frame, A method wherein the first frame is transmitted to the first AP after the third frame is transmitted, based on the second information being included in the third frame.

11. In paragraph 9, A method in which the first delay-sensitive traffic is transmitted to the first AP with priority over delay-sensitive traffic of other STAs based on the second information indicating that the first delay-sensitive traffic is urgent.

12. In a first STA affiliated with a first non-access point (AP) multi-link device (MLD), the first STA: one or more transmitters and receivers; and comprising one or more processors connected to said one or more transceivers, One or more of the above processors: Receiving a first trigger frame including at least one delay bound from a first AP through said one or more transceivers; Transmitting a first frame including first information related to a size of first delay-sensitive traffic to be transmitted within at least one delay bound to the first AP via the one or more transceivers; Receiving a second trigger frame including second information related to a first resource unit for the first delay-sensitive traffic from the first AP through the one or more transceivers; and A first STA configured to transmit a second frame including the first delay-sensitive traffic to the first AP through the one or more transceivers based on the second trigger frame.

13. A method performed by a first access point (AP) multi-link device (MLD), the method comprising: A step of transmitting a first trigger frame including at least one delay bound to a first station (STA) by a first AP affiliated to the first AP MLD; A step of receiving, by the first AP, from the first STA a first frame including first information related to a size of first delay sensitive traffic to be transmitted within the at least one delay bound; A step of transmitting a second trigger frame including second information related to a first resource unit for the first delay-sensitive traffic to the first STA by the first AP; and A method comprising the step of receiving, by the first AP, a second frame including the first delay-sensitive traffic from the first STA based on the second trigger frame.

14. In the first AP affiliated to the first access point (AP) multi-link device (MLD), the first AP: one or more transmitters and receivers; and comprising one or more processors connected to said one or more transceivers, One or more of the above processors: Transmitting a first trigger frame including at least one delay bound to a first STA via the one or more transceivers; Receiving a first frame from the first STA via the one or more transceivers, the first frame including first information related to a size of first delay-sensitive traffic to be transmitted within the at least one delay bound; Transmitting a second trigger frame including second information related to a first resource unit for the first delay-sensitive traffic to the first STA via the one or more transceivers; and A first AP configured to receive a second frame including the first delay-sensitive traffic from the first STA through the one or more transceivers based on the second trigger frame.

15. In a processing device configured to control a station (STA) in a wireless local area network (WLAN) system, the processing device: one or more processors; and A processing device comprising one or more computer memories operatively connected to said one or more processors and storing instructions for performing a method according to any one of claims 1 to 11 based on execution by said one or more processors.

16. One or more non-transitory computer-readable media storing one or more instructions, A computer-readable medium, wherein the one or more commands are executed by one or more processors to control a device in a wireless LAN system to perform a method according to any one of claims 1 to 11.

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