Method and apparatus for transmitting and receiving information based on enhanced multi-link single radio mode in wireless LAN system

Abstract

Disclosed are an information transmission and reception method and apparatus based on an Enhanced Multilink Single Radio (EMLSR) mode in a wireless LAN system. According to one embodiment of the present disclosure, a method performed by an STA belonging to a first MLD may comprise the steps of: receiving a multi-link element related to establishment of a plurality of links from an STA belonging to a second MLD; receiving a control frame for initiating an EMLSR mode from the STA belonging to the second MLD; and exchanging a frame with the STA belonging to the second MLD based on the EMLSR mode. Here, the multi-link element may include information on at least one link related to the EMLSR mode among the plurality of links.

Description

TECHNICAL FIELD

[0001] The disclosure relates to a method and apparatus for transmitting and receiving information based on an enhanced multi-link single radio (EMLSR) mode in a wireless local area network (WLAN) system. BACKGROUND

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

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

[0004] TECHNICAL PROBLEM

[0005] The technical object of the disclosure is to provide a method and apparatus for transmitting and receiving information based on an enhanced multi-link single radio (EMLSR) mode in a wireless LAN system.

[0006] An additional technical object of the disclosure is to provide a method and apparatus for indicating a link related to an EMLSR mode in a wireless LAN system.

[0007] The technical objects to be achieved by the disclosure are not limited to the aforementioned technical objects and other technical objects not described herein will be clearly understood by a person skilled in the art from the following description.

[0008] TECHNICAL SOLUTION

[0009] A method performed by a station (STA) belonging to a first multi-link device (MLD) in a wireless LAN system according to an aspect of the disclosure can include receiving, from a STA belonging to a second MLD, a multi-link element related to establishment of a plurality of links, receiving, from the STA belonging to the second MLD, a control frame for initiating an enhanced multi-link single radio (EMLSR) mode, and performing frame exchange with a STA belonging to the second MLD based on the EMLSR mode. Here, the multi-link element can include information for at least one link among the plurality of links related to the EMLSR mode.

[0010] A method performed by a station (STA) belonging to a second multi-link device (MLD) in a wireless LAN system according to an additional aspect of the disclosure can include transmitting, to a STA belonging to a first MLD, a multi-link element related to establishment of a plurality of links, transmitting, to the STA belonging to the first MLD, a control frame for initiating an enhanced multi-link single radio (EMLSR) mode, and performing frame exchange with a STA belonging to the first MLD based on the EMLSR mode. Here, the multi-link element can include information for at least one link among the plurality of links related to the EMLSR mode.

[0011] Technical Effects

[0012] According to the disclosure, a method and apparatus for transmitting and receiving information based on an enhanced multi-link single radio (EMLSR) mode in a wireless LAN system can be provided.

[0013] According to the disclosure, a method and apparatus for indicating a link related to an EMLSR mode in a wireless LAN system can be provided.

[0014] Effects that the disclosure can achieve are not limited to the above-mentioned effects, and other effects not described herein can be clearly understood by those skilled in the relevant art from the following description. BRIEF DESCRIPTION OF DRAWINGS

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

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

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

[0018] Figure 3 is a diagram for explaining a link establishment process to which the disclosure can be applied.

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

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

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

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

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

[0024] Figure 9 illustrates an example of an MLD structure to which the present disclosure can be applied.

[0025] Figure 10 illustrates an example of a structure of an ML element to which the present disclosure can be applied.

[0026] Figure 11 illustrates an EMLSR mode-based operation to which the present disclosure can be applied.

[0027] Figure 12 illustrates an EML capability subfield format included in a common information field within an ML element to which the present disclosure can be applied.

[0028] Figure 13 illustrates an STA control field format and an STA information field format included in a per-STA profile subelement to which the present disclosure can be applied.

[0029] Figure 14 illustrates information of an EMLSR link indicated / provided through a link information field according to an embodiment of the present disclosure.

[0030] Figure 15 illustrates a detailed example of an EMLSR indication bitmap included in a link information field according to an embodiment of the present disclosure.

[0031] Figure 16 illustrates information for an EMLSR link indicated / provided through a common information field according to an embodiment of the present disclosure.

[0032] Figure 17 illustrates a detailed example of an EMLSR indication bitmap included in a common information field according to an embodiment of the present disclosure.

[0033] Figure 18 An EML capability subfield within a public information field including information indicating that it is an EMLSR MLD according to an embodiment of the disclosure is exemplified.

[0034] Figure 19 An operation flowchart of a STA belonging to a first MLD according to an embodiment of the disclosure is exemplified.

[0035] Figure 20 An operation flowchart of a STA belonging to a second MLD according to an embodiment of the disclosure is exemplified. DETAILED DESCRIPTION

[0036] Hereinafter, embodiments according to the disclosure will be described in detail with reference to the accompanying drawings. The detailed description disclosed by the accompanying drawings is to describe exemplary embodiments of the disclosure and is not intended to represent the only embodiments in which the disclosure can be implemented. The following detailed description includes specific details to provide a complete understanding of the disclosure. However, it will be apparent to those skilled in the art that the disclosure can be implemented without the specific details.

[0037] In some cases, known structures and devices can be omitted, or can be shown in the form of a block diagram based on each core function in order to facilitate the prevention of obscuring the concept of the disclosure.

[0038] In the disclosure, when an element is referred to as being "connected", "combined", or "linked" to another element, it can include an indirect connection relationship between the other element and a further element existing therebetween as well as a direct connection relationship. In addition, in the disclosure, the term "including" or "having" specifies the existence of the mentioned features, steps, operations, components, and / or elements, but does not exclude the existence or addition of one or more other features, stages, operations, components, elements, and / or groups thereof.

[0039] In the disclosure, terms such as "first", "second", and the like are used only to distinguish one element from another element and are not used to limit the elements, unless otherwise specified, and do not limit the order or importance between the elements, etc. Therefore, within the scope of the disclosure, a first element in an embodiment can be referred to as a second element in another embodiment, and likewise, a second element in an embodiment can be referred to as a first element in another embodiment.

[0040] The terms used in the present disclosure are used to describe specific embodiments and are not intended to limit the claims. As used in the description of the embodiments and the appended claims, the singular forms are intended to include the plural forms as well, unless the context clearly indicates otherwise. The term "and / or" used in the present disclosure can refer to one of the relevant listed items, or mean that it refers to and includes any and all possible combinations of two or more of them. In addition, unless otherwise stated, " / " between words in the present disclosure has the same meaning as "and / or".

[0041] Examples of the present disclosure can be applied to various wireless communication systems. For example, examples of the present disclosure can be applied to a wireless LAN system. For example, examples of the present disclosure can be applied to a wireless LAN based on IEEE 802.11a / g / n / ac / ax standards. In addition, examples of the present disclosure can be applied to a wireless LAN based on a newly proposed IEEE 802.11be (or EHT) standard. Examples of the present disclosure can be applied to a wireless LAN based on an IEEE 802.11be version 2 standard corresponding to additional enhancement technologies of the IEEE 802.11be version 1 standard. In addition, examples of the present disclosure can be applied to a wireless LAN based on a next-generation standard after the IEEE 802.11be. Furthermore, examples of the present disclosure can be applied to a cellular wireless communication system. For example, it can be applied to a long-term evolution (LTE)-based technology based on a third generation partnership project (3GPP) standard and a cellular wireless communication system based on a 5G new radio (NR) technology.

[0042] Hereinafter, technical features to which examples of the present disclosure can be applied will be described.

[0043] Figure 1 A block diagram of a wireless communication device according to an embodiment of the present disclosure is illustrated.

[0044] Figure 1 The first device 100 and the second device 200 illustrated in the middle can be replaced with various terms such as a terminal, a wireless device, a wireless transmit / receive unit (WTRU), a user equipment (UE), a mobile station (MS), a user terminal (UT), a mobile subscriber station (MSS), a mobile subscriber unit (MSU), a subscriber station (SS), an advanced mobile station (AMS), a wireless terminal (WT), or simply a user, etc. In addition, the first device 100 and the second device 200 include an access point (AP), a base station (BS), a fixed station, a node B, a base transceiver system (BTS), a network. It can be replaced with various terms such as an artificial intelligence (AI) system, a road side unit (RSU), a repeater, a router, a relay, and a gateway.

[0045] Figure 1The apparatuses 100 and 200 exemplified in the middle can be referred to as stations (STAs). For example, Figure 1 The apparatuses 100 and 200 exemplified in the middle can be referred to with various terms such as a transmitting apparatus, a receiving apparatus, a transmitting STA, and a receiving STA. For example, the STAs 110 and 200 can perform an access point (AP) role or a non-AP role. That is, in the present disclosure, the STAs 110 and 200 can perform the functions of an AP and / or a non-AP. When the STAs 110 and 200 perform the AP function, they can be simply referred to as an AP, and when the STAs 110 and 200 perform the non-AP function, they can be simply referred to as a STA. In addition, in the present disclosure, an AP can also be indicated as an AP STA.

[0046] Referring to Figure 1 The first apparatus 100 and the second apparatus 200 can transmit and receive radio signals through various wireless LAN technologies (for example, IEEE 802.11 series). The first apparatus 100 and the second apparatus 200 can include an interface for a medium access control (MAC) layer and a physical layer (PHY) to comply with the IEEE 802.11 standard.

[0047] In addition, the first apparatus 100 and the second apparatus 200 can additionally support various communication standard (for example, 3GPP LTE series, 5G NR series standards, etc.) technologies in addition to the wireless LAN technology. In addition, the apparatuses of the present disclosure can be implemented in various apparatuses such as a mobile phone, a vehicle, a personal computer, an augmented reality (AR) apparatus, and a virtual reality (VR) apparatus. In addition, the STAs of the present specification can support various communication services such as a voice call, a video call, data communication, autonomous driving, machine type communication (MTC), machine-to-machine (M2M), device-to-device (D2D), IoT (Internet of Things), etc.

[0048] The first device 100 may include one or more processors 102 and one or more memories 104, and may additionally include one or more transceivers 106 and / or one or more antennas 108. The processors 102 may control the memories 104 and / or the transceivers 106, and may be configured to implement the descriptions, functions, processes, suggestions, methods, and / or operation flowcharts included in this disclosure. For example, the processor 102 may transmit a wireless signal including the first information / signal via the transceivers 106 after generating first information / signal by processing information in the memories 104. Additionally, the processor 102 may receive a wireless signal including second information / signal via the transceivers 106, and then store information obtained through signal processing of the second information / signal in the memories 104. The memories 104 may be connected to the processor 102 and may store various information related to the operation of the processor 102. For example, the memories 104 may store software code including instructions for performing all or part of the processing controlled by the processor 102 or for performing the descriptions, functions, processes, suggestions, methods, and / or operation flowcharts included in this disclosure. Here, processor 102 and memory 104 may be part of a communication modem / circuit / chip designed to implement wireless LAN technology (e.g., IEEE 802.11 series). Transceiver 106 may be connected to processor 102 and may transmit and / or receive wireless signals via one or more antennas 108. Transceiver 106 may include a transmitter and / or a receiver. Transceiver 106 may be used with an RF (radio frequency) unit. In this disclosure, wireless device may refer to a communication modem / circuit / chip.

[0049] The second device 200 may include one or more processors 202 and one or more memories 204, and may additionally include one or more transceivers 206 and / or one or more antennas 208. The processors 202 may control the memories 204 and / or the transceivers 206, and may be configured to implement the descriptions, functions, processes, suggestions, methods, and / or operation flowcharts included in this disclosure. For example, the processors 202 may generate third information / signals by processing information in the memories 204, and then transmit a wireless signal including the third information / signals via the transceivers 206. Additionally, the processors 202 may receive wireless signals including fourth information / signals via the transceivers 206, and then store information obtained through signal processing of the fourth information / signals in the memories 204. The memories 204 may be connected to the processors 202 and may store various information related to the operation of the processors 202. For example, the memories 204 may store software code including instructions for performing all or part of the processing controlled by the processors 202 or for performing the descriptions, functions, processes, suggestions, methods, and / or operation flowcharts included in this disclosure. Here, processor 202 and memory 204 may be part of a communication modem / circuit / chip designed to implement wireless LAN technology (e.g., IEEE 802.11 series). Transceiver 206 may be connected to processor 202 and may transmit and / or receive wireless signals via one or more antennas 208. Transceiver 206 may include a transmitter and / or a receiver. Transceiver 206 may be used with an RF unit. In this disclosure, apparatus may refer to a communication modem / circuit / chip.

[0050] The hardware elements of devices 100 and 200 will be described in more detail below. Not limited thereto, one or more protocol layers may be implemented by one or more processors 102 and 202. For example, one or more processors 102 and 202 may implement one or more layers (e.g., functional layers such as PHY and MAC). One or more processors 102 and 202 may generate one or more PDUs (Protocol Data Units) and / or one or more SDUs (Service Data Units) according to the descriptions, functions, processes, suggestions, methods, and / or operation flowcharts disclosed in this disclosure. One or more processors 102 and 202 may generate messages, control information, data, or information according to the descriptions, functions, processes, suggestions, methods, and / or operation flowcharts disclosed in this disclosure. One or more processors 102 and 202 may generate signals (e.g., baseband signals) including PDUs, SDUs, messages, control information, data, or information according to the functions, processes, suggestions, and / or methods disclosed in this disclosure to provide them to one or more transceivers 106 and 206. One or more processors 102, 202 may receive signals (e.g., baseband signals) from one or more transceivers 106, 206 and obtain PDUs, SDUs, messages, control information, data or information, in accordance with the description, functions, processes, suggestions, methods and / or operation flowcharts included in this disclosure.

[0051] One or more processors 102, 202 may be referred to as controllers, microcontrollers, microprocessors, or microcomputers. One or more processors 102, 202 may be implemented by hardware, firmware, software, or a combination thereof. For example, one or more ASICs (Application-Specific Integrated Circuits), one or more DSPs (Digital Signal Processors), one or more DSPDs (Digital Signal Processing Devices), one or more PLDs (Programmable Logic Devices), or one or more FPGAs (Field-Programmable Gate Arrays) may be included in one or more processors 102, 202. The descriptions, functions, processes, suggestions, methods, and / or operation flowcharts included in this disclosure may be implemented using firmware or software, and the firmware or software may be implemented to include modules, processes, functions, etc. Firmware or software configured to execute the descriptions, functions, processes, suggestions, methods, and / or operation flowcharts included in this disclosure may be included in one or more processors 102, 202, or may be stored in one or more memories 104, 204 and driven by one or more processors 102, 202. The descriptions, functions, processes, suggestions, methods and / or operation flowcharts included in this disclosure may be implemented using firmware or software in the form of code, instructions and / or instruction sets.

[0052] One or more memories 104, 204 may be connected to one or more processors 102, 202 and may store data, signals, messages, information, programs, code, instructions, and / or commands in various forms. One or more memories 104, 204 may be configured with ROM, RAM, EPROM, flash memory, hard disk drive, registers, cache memory, computer-readable storage media, and / or combinations thereof. One or more memories 104, 204 may be located internally and / or externally to one or more processors 102, 202. Furthermore, one or more memories 104, 204 may be connected to one or more processors 102, 202 via various technologies such as wired or wireless connections.

[0053] One or more transceivers 106, 206 can transmit user data, control information, wireless signals / channels, etc., mentioned in the methods and / or operation flowcharts of this disclosure to one or more other devices. One or more transceivers 106, 206 can receive user data, control information, wireless signals / channels, etc., mentioned in the descriptions, functions, processes, suggestions, methods, and / or operation flowcharts included in this disclosure from one or more other devices. For example, one or more transceivers 106, 206 can be connected to one or more processors 102, 202 and can transmit and receive wireless signals. For example, one or more processors 102, 202 can control one or more transceivers 106, 206 to transmit user data, control information, or wireless signals to one or more other devices. Additionally, one or more processors 102, 202 can control one or more transceivers 106, 206 to receive user data, control information, or wireless signals from one or more other devices. Additionally, one or more transceivers 106, 206 may be connected to one or more antennas 108, 208, and one or more transceivers 106, 206 may be configured to transmit and receive user data, control information, wireless signals / channels, etc., mentioned in the descriptions, functions, processes, suggestions, methods, and / or operation flowcharts included in this disclosure, via one or more antennas 108, 208. In this disclosure, one or more antennas may be multiple physical antennas or multiple logical antennas (e.g., antenna ports). One or more transceivers 106, 206 may convert received wireless signals / channels, etc., from RF band signals into baseband signals for processing using one or more processors 102, 202. One or more transceivers 106, 206 may convert user data, control information, wireless signals / channels, etc., processed using one or more processors 102, 202, from baseband signals into RF band signals. Therefore, one or more transceivers 106, 206 may include (analog) oscillators and / or filters.

[0054] For example, one of STAs 100 and 200 can perform the expected operation of an AP, and the other of STAs 100 and 200 can perform the expected operation of a non-AP STA. For example, Figure 1 Transceivers 106 and 206 can perform transmission and reception operations of signals (e.g., packet or physical layer protocol data units (PPDUs) conforming to IEEE 802.11a / b / g / n / ac / ax / be / bn). Additionally, in this disclosure, the various STAs can generate transmit / receive signals or perform data processing or calculations on the transmit / receive signals in advance by [the relevant entity / component]. Figure 1Processors 102 and 202 perform the following operations: For example, examples of generating transmit / receive signals or performing data processing or computations on transmit / receive signals in advance may include: 1) determining / acquiring / configuring / computing / decoding / encoding bit information of fields (signals (SIG), short training field (STF), long training field (LTF), data, etc.) included in the PPDU; 2) determining / configuring / acquiring time or frequency resources (e.g., subcarrier resources) for the fields (SIG, STF, LTF, data, etc.) included in the PPDU; 3) determining / configuring / acquiring specific sequences (e.g., pilot sequences, STF / LTF sequences, additional sequences applied to SIG) for the fields (SIG, STF, LTF, data, etc.) included in the PPDU action; 4) power control operations and / or power saving operations applied to the STA; 5) operations related to determining / acquiring / configuring / computing / decoding / encoding the ACK signal. Additionally, in the example below, various information used by different STAs to determine / acquire / configure / calculate / decode / encode transmitted and received signals (e.g., information related to fields / subfields / control fields / parameters / power, etc.) can be stored. Figure 1 In memory 104 and 204.

[0055] In the following text, downlink (DL) can refer to a link used for communication from an AP STA to a non-AP STA, and DL PPDU / packets / signals can be sent and received via DL. In DL communication, the transmitter can be part of an AP STA, and the receiver can be part of a non-AP STA. Uplink (UL) can refer to a link used for communication from a non-AP STA to an AP STA, and UL PPDU / packets / signals can be sent and received via UL. In UL communication, the transmitter can be part of a non-AP STA, and the receiver can be part of an AP STA.

[0056] Figure 2 This is a diagram illustrating an exemplary structure of a wireless LAN system to which this disclosure can be applied.

[0057] A wireless LAN system can be structured by multiple components. These components interact to provide STA mobility support that is transparent to upper layers. The Basic Service Set (BSS) corresponds to the basic building blocks of a wireless LAN. Figure 2 An example is shown where there are two BSSs (BSS1 and BSS2), and two STAs included as members of each BSS (STA1 and STA2 are included in BSS1, and STA3 and STA4 are included in BSS2). Figure 2The ellipse representing the BSS can also be interpreted as representing the coverage area within the corresponding BSS where STAs maintain communication. This area can be called the Basic Service Area (BSA). When a STA moves outside the BSA, it cannot communicate directly with other STAs within the BSA.

[0058] If we do not consider Figure 2 The DS shown in the diagram represents the most basic BSS type in a wireless LAN: the Independent BSS (IBSS). For example, an IBSS can have a minimal form containing only two STAs. For instance, assuming other components are omitted, BSS1 containing only STA1 and STA2, or BSS2 containing only STA3 and STA4, can respectively correspond to representative examples of IBSS. This configuration is possible when STAs can communicate directly without an AP. Furthermore, in this type of wireless LAN, it is not pre-configured but can be configured as needed, 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 an IBSS, all STAs can consist of mobile STAs and are not allowed to access the Distributed System (DS), thus forming a self-contained network.

[0059] Membership of an STA in a BSS can be dynamically changed by opening or closing an STA, or by entering or leaving a BSS zone. To become a member of a BSS, an STA can join the BSS using a synchronization process. To access all services of the BSS infrastructure, an STA must be associated with the BSS. This association can be dynamically established and may include the use of Distributed System Services (DSS).

[0060] Direct STA-to-STA distance in a wireless LAN may be limited by PHY performance. In some cases, this distance limitation may be sufficient, but in others, longer distances between STAs may be required for communication. Distributed systems (DS) can be configured to support extended coverage.

[0061] DS refers to the structure of BSS interconnection. Specifically, such as... Figure 2As shown, a BSS can exist as an extension of a network composed of multiple BSSs. A DS is a logical concept and can be specified through the characteristics of the Distributed System Medium (DSM). At this point, the Wireless Medium (WM) and the DSM can be logically separated. Each logical medium is used for a different purpose and by different components. These media are not limited to being the same, nor are they limited to being different. In this way, the flexibility of a wireless LAN architecture (DS architecture or other network architectures) can be interpreted as multiple media being logically different. That is, a wireless LAN architecture can be implemented in various ways, and the corresponding wireless LAN architecture can be independently specified by the physical characteristics of each implementation.

[0062] The DS can support mobile devices by providing seamless integration of multiple BSSs and offering the logical services necessary for addressing to the destination. Additionally, the DS may include a component called a portal, which acts as a bridge between the wireless LAN and other networks, such as IEEE 802.X.

[0063] AP enables access to DS via WM for associated non-AP STAs, and refers to entities that also have STA functionality. Data movement between BSS and DS can be performed through AP. For example, Figure 2 STA2 and STA3, shown in the diagram, have the functionality of STAs and provide the ability for associated non-AP STAs (STA1 and STA4) to access the DS. Furthermore, since all APs essentially correspond to STAs, all APs are addressable entities. The address used by an AP for communication on the WM is not necessarily the same as the address used by the AP for communication on the DSM. A BSS consisting of APs and one or more STAs can be referred to as an infrastructure BSS.

[0064] Data sent from one of the STAs associated with the AP to the corresponding STA address of the AP can always be received on an uncontrolled port and can be processed by the IEEE 802.1X port access entity. Alternatively, when the controlled port is authenticated, the transmitted data (or frames) can be delivered to the DS.

[0065] In addition to the DS structure described above, Extended Service Sets (ESS) can also be configured to provide wide coverage.

[0066] An ESS (Service Set Identity) refers to a network of arbitrary size and complexity consisting of DS (Service Controller) and BSS (Service Set Service). An ESS can correspond to a set of BSSs connected to a DS. However, an ESS does not include the DS. An ESS network is characterized as an IBSS (Integrated Service Set Service) within the Logical Link Control (LLC) layer. STAs included in an ESS can communicate with each other, and a moving STA can transparently move from one BSS to another (within the same ESS) to the LLC. APs included in an ESS can have the same Service Set Identity (SSID). The SSID is distinguished from the BSSID, which serves as the identifier for the BSS.

[0067] Wireless LAN systems make no assumptions about the relative physical locations of BSSs, and all of the following forms are possible: BSSs can partially overlap, which is a common form used to provide continuous coverage. Additionally, BSSs may not be physically connected, and logically, there is no limit to the distance between BSSs. Furthermore, BSSs can be physically located in the same location, which can be used to provide redundancy. Additionally, one (or more) IBSS or ESS networks can physically exist in the same space as one (or more) ESS networks. This can correspond to the form of ESS networks when an ad hoc network operates in a location where an ESS network exists, when physically overlapping wireless networks are configured by different organizations, or when two or more different access and security policies are required in the same location, etc.

[0068] Figure 3 This is a diagram illustrating the link establishment process that can be applied to this disclosure.

[0069] In order for a STA to establish a link with the network and send / receive data, it first discovers the network, performs authentication, establishes an association, and performs authentication processing for security. The link establishment process can also be called session initiation processing or session establishment processing. Furthermore, the discovery, authentication, association, and security establishment processes of the link establishment process can be collectively referred to as association processing.

[0070] In step S310, the STA can perform a network discovery operation. The network discovery operation may include a scanning operation by the STA. That is, in order for the STA to access a network, it needs to find networks it can participate in. The STA should identify compatible networks before participating in a wireless network, and the process of identifying networks existing in a specific area is called scanning.

[0071] Scanning schemes include active scanning and passive scanning. Figure 3An exemplary network discovery operation including active scanning processing is illustrated. In active scanning, the STA performing the scan sends a probe request frame to discover which APs are present around it as the channel moves and awaits a response. The responder sends a probe response frame as a response to the probe request frame to the STA that sent the probe request frame. Here, the responder may be the STA that last sent a beacon frame in the BSS of the channel being scanned. In the BSS, the AP becomes the responder because it sends a beacon frame, and in the IBSS, the STAs in the IBSS rotate to send beacon frames, so the responder is not constant. For example, an STA that sends a probe request frame on channel 1 and receives a probe response frame on channel 1 may store the BSS-related information included in the received probe response frame and may move to the next channel (e.g., channel 2) and perform a scan in the same manner (i.e., sending and receiving probe requests / responses on channel 2).

[0072] Although not in Figure 3 As shown, scanning can be performed passively. In passive scanning, the STA performing the scan waits for beacon frames while moving through the channel. Beacon frames are one of the management frames defined in IEEE 802.11 and are sent periodically to notify of the existence of a wireless network and allow the STA performing the scan to find and participate in the wireless network. In the BSS, the AP periodically sends beacon frames, and in the IBSS, the STA within the IBSS rotates to send beacon frames. When the STA performing the scan receives a beacon frame, it stores the BSS information included in the beacon frame and records the beacon frame information for each channel while moving to another channel. The STA receiving the beacon frame can store the BSS-related information included in the received beacon frame, move to the next channel, and perform scanning in the next channel in the same manner. Comparing active and passive scanning, active scanning has the advantages of less latency and less power consumption.

[0073] After the STA discovers the network, an authentication process can be performed in step S320. To clearly distinguish it from the security establishment operation in step S340, which will be described later, this authentication process can be referred to as the first authentication process.

[0074] The authentication process includes the following steps: the STA sends an authentication request frame to the AP, and in response, the AP sends an authentication response frame to the STA. The authentication frame used for the authentication request / response corresponds to the management frame.

[0075] An authentication frame includes the authentication algorithm number, authentication transaction sequence number, status code, challenge text, robust security network (RSN), and finite circular group. These correspond to some examples of information that can be included in the authentication request / response frame and can be replaced with other information, or additional information may be included.

[0076] A STA can send an authentication request frame to an AP. The AP can determine whether to allow the corresponding STA's authentication based on the information included in the received authentication request frame. The AP can then provide the STA with the authentication processing result via an authentication response frame.

[0077] After the STA is successfully authenticated, the association process can be performed in step S330. The association process includes the following steps: the STA sends an association request frame to the AP, and in response, the AP sends an association response frame to the STA.

[0078] For example, an association request frame may include information related to various capabilities, beacon listening intervals, service set identifiers (SSIDs), supported rates, supported channels, RSNs, mobile domains, supported operation classes, service indication mapping broadcast requests (TIM broadcast requests), interoperability capabilities, etc. Similarly, an association response frame may include information related to various capabilities, status codes, association IDs (AIDs), supported rates, enhanced distributed channel access (EDCA) parameter sets, received channel power indicators (RCPIs), received signal-to-noise ratio indicators (RSNIs), mobile domains, timeout intervals (e.g., association recovery time), overlapping BSS scan parameters, TIM broadcast responses, quality of service (QoS) mappings, etc. These correspond to some examples of information that can be included in association request / response frames and may be replaced with other information, or additional information may be included.

[0079] After the STA successfully associates with the network, a security establishment process can be performed in step S340. The security establishment process in step S340 can be referred to as the authentication process via a Robust Secure Network Association (RSNA) request / response, the authentication process in step S320 is referred to as the first authentication process, and the security establishment process in step S340 can also be simply referred to as the authentication process.

[0080] The secure establishment process in step S340 may include, for example, the process of establishing a private key using a four-way handshake via Extensible Authentication Protocol (EAPOL) frames over the LAN. Alternatively, the secure establishment process may be performed according to a security scheme not defined in the IEEE 802.11 standard.

[0081] Figure 4 This is a diagram illustrating the fallback process that can be applied to this disclosure.

[0082] In wireless LAN systems, the basic access mechanism for Media Access Control (MAC) is Carrier Sensing Multiple Access with Collision Avoidance (CSMA / CA). Also known as the Distributed Coordination Function (DCF) of IEEE 802.11 MAC, CSMA / CA essentially employs a "listen-before-talk" access mechanism. Under this type of access mechanism, before commencing transmission, the AP and / or STA can perform explicit channel assessment (CCA) of the sensing radio channel or medium during a predetermined time interval (e.g., the DCF inter-frame interval (DIFS)). As a result of the sensing, if it is determined that the medium is idle, frame transmission begins via the corresponding medium. Conversely, if the medium is detected to be occupied or busy, the corresponding AP and / or STA does not begin its own transmission and can set a delay period for medium access (e.g., a random backoff period) and attempt frame transmission after waiting. By applying a random backoff period, collisions can be minimized because multiple STAs are expected to attempt frame transmission after waiting for different time periods.

[0083] In addition, the IEEE 802.11 MAC protocol provides a Hybrid Coordination Function (HCF). HCF is based on DCF and Point Coordination Function (PCF). PCF is a polling-based synchronous access method, meaning that all receiving APs and / or STAs periodically poll to receive data frames. Furthermore, HCF includes Enhanced Distributed Channel Access (EDCA) and HCF Control Channel Access (HCCA). EDCA is a contention-based access method that provides data frames to multiple users, while HCCA uses a non-contention-based channel access method that utilizes a polling mechanism. Additionally, HCF includes a media access mechanism for improving the QoS (Quality of Service) of wireless LANs and can transmit QoS data during both contention-based (CP) and contention-free (CFP) periods.

[0084] Reference Figure 4 This section describes the operation based on a random backoff period. When an occupied / busy medium becomes idle, multiple STAs can attempt to transmit data (or frames). As a method to minimize collisions, each STA can individually select a random backoff count and attempt to transmit after waiting for the corresponding time slot. The random backoff count has a pseudo-random integer value and can be determined as one of the values ​​ranging from 0 to CW. Here, CW is the contention window parameter value. The CW parameter is assigned an initial value of CWmin, but can take a value twice as large as in the event of transmission failure (e.g., when no ACK is received for the transmitted frame). When the CW parameter value reaches CWmax, data transmission can be attempted while maintaining the CWmax value until successful data transmission, and when successful, the CWmin value is reset. The values ​​of CW, CWmin, and CWmax are preferably set to 2.n -1 (n=0, 1, 2,...).

[0085] When random backoff processing begins, the STA continuously monitors the medium during the backoff time slot countdown based on the determined backoff count value. When monitoring the medium for occupancy, it stops the countdown and waits, and restarts the remainder of the countdown when the medium becomes idle.

[0086] exist Figure 4 In the example, when the packet to be sent arrives at STA 3's MAC, STA 3 can send the frame immediately after confirming that the medium has been idle for up to DIFS. The remaining STAs monitor and wait for the medium to be occupied / busy. Meanwhile, the data to be sent can also occur in each of STA 1, STA 2, and STA 5, and when the medium is detected as idle, each STA waits for up to DIFS, and then performs a countdown for the backoff slot based on a random backoff count value chosen by each STA. Assume STA 2 chooses the minimum backoff count value, and STA 1 chooses the maximum backoff count value. That is, the example illustrates the case where STA 5's remaining backoff time is shorter than STA 1's remaining backoff time when STA 2 completes its backoff count and begins frame transmission. STA 1 and STA 5 temporarily stop the countdown and wait while STA 2 occupies the medium. When STA 2's occupancy ends and the medium becomes idle again, STA 1 and STA 5 wait for DIFS and restart the stopped backoff count. In other words, frame transmission can begin after a countdown for the remaining backoff slot based on the remaining backoff time. Since STA5 has a shorter remaining backoff time than STA1, STA5 begins frame transmission. Data to be transmitted can also occur in STA4 while STA2 is occupying the medium. From STA4's perspective, when the medium becomes idle, STA4 can wait for DIFS, then execute a countdown based on a random backoff count value selected by STA4, and begin transmitting frames. Figure 4 The example illustrates a scenario where the remaining backoff time of STA5 accidentally conflicts with the random backoff count value of STA4. In this case, a collision may occur between STA4 and STA5. When a collision occurs, neither STA4 nor STA5 receives an ACK, so data transmission fails. In this situation, STA4 and STA5 can double the CW value, select a random backoff count value, and begin a countdown. While the medium is occupied due to the transmissions of STA4 and STA5, STA1 waits; when the medium becomes idle, STA1 waits for DIFS, and then begins frame transmission after the remaining backoff time has elapsed.

[0087] As in Figure 4In the example, data frames are frames used to send data forwarded to higher layers and can be sent after a backoff performed after DIFS, starting from when the medium becomes idle. Additionally, management frames are frames used to exchange management information that has not been forwarded to higher layers and are sent after a backoff performed after an IFS such as DIFS or Point Coordination Function IFS (PIFS). Subtypes of management frames include beacons, association requests / responses, reassociation requests / responses, probe requests / responses, authentication requests / responses, etc. Control frames are frames used to control access to the medium. Subtypes of control frames include request to send (RTS), clear send (CTS), acknowledge (ACK), power-saving polling (PS-Poll), block ACK (BlockAck), block ACK request (BlockACKReq), empty data packet announcement (NDP announcement), and triggers, etc. If a control frame is not a response frame to the previous frame, it is sent after a backoff performed after DIFS; if it is a response frame to the previous frame, it is sent without a backoff performed after short IFS (SIFS). The type and subtype of a frame can be identified by the type field and subtype field in the Frame Control (FC) field.

[0088] The Quality of Service (QoS) ST can perform a backoff following the Arbitration IFS (AIFS) for the Access Class (AC) to which the frame belongs (i.e., AIFS where i is a value determined by the AC) before the frame can be transmitted. Here, the frame that can use AIFS can be a data frame, management frame, or control frame, rather than a response frame.

[0089] Figure 5 This is a diagram illustrating the CSMA / CA-based frame transmission operation that can be applied to this disclosure.

[0090] As mentioned above, in addition to physical carrier sensing of the medium directly sensed by the STA, the CSMA / CA mechanism also includes virtual carrier sensing. Virtual carrier sensing aims to compensate for problems such as hidden node issues that may occur during medium access. For virtual carrier sensing, the STA's MAC can use the Network Allocation Vector (NAV). The NAV is a value that indicates to other STAs the remaining time until the medium is available for current use or for STAs authorized to use the medium. Therefore, a value set to NAV corresponds to the period during which the STA sending the frame plans to use the medium, and during the corresponding period, STAs receiving the NAV value are prohibited from accessing the medium. For example, the NAV can be configured based on the value of the "Duration" field in the frame's MAC header.

[0091] exist Figure 5 In the example, it is assumed that STA1 intends to send data to STA2, and STA3 is in a position that allows it to eavesdrop on some or all of the frames sent and received between STA1 and STA2.

[0092] To reduce the likelihood of transmission conflicts among multiple STAs in CSMA / CA-based frame transmission operations, a mechanism using RTS / CTS frames can be applied. Figure 5 In the example, when STA1 is transmitting, as a result of carrier sensing by STA3, it can be determined that the medium is in an idle state. That is, STA1 can correspond to a hidden node with respect to STA3. Alternatively, in Figure 5 In the example, it can be determined that while STA2 is transmitting, the carrier sensing result medium of STA3 is in an idle state. That is, STA2 can correspond to a hidden node with respect to STA3. By exchanging RTS / CTS frames before performing data transmission and reception between STA1 and STA2, STAs outside the transmission range of either STA1 or STA2, or STAs outside the carrier sensing range of transmissions from STA1 or STA3, can avoid attempting to occupy the channel during data transmission and reception between STA1 and STA2.

[0093] Specifically, STA1 can determine whether a channel is in use through carrier sensing. Regarding physical carrier sensing, STA1 can determine the channel occupancy / idle status based on the energy level or signal correlation detected in the channel. Alternatively, regarding virtual carrier sensing, STA1 can use a Network Allocation Vector (NAV) timer to determine the channel occupancy status.

[0094] When the channel is idle during DIFS, STA1 can send an RTS frame to STA2 after performing backoff. When STA2 receives the RTS frame, STA2 can send a CTS frame to STA1 after SIFS as a response to the RTS frame.

[0095] If STA3 cannot eavesdrop on CTS frames from STA2 but can eavesdrop on RTS frames from STA1, STA3 can use the duration information included in the RTS frame to set the NAV timer for the subsequent consecutive frame transmission period (e.g., SIFS+CTS frame+SIFS+data frame+SIFS+ACK frame). Alternatively, if STA3 can eavesdrop on CTS frames from STA2, STA3 can also use the duration information included in the CTS frame to set the NAV timer for the subsequent consecutive frame transmission period (e.g., SIFS+data frame+SIFS+ACK frame) even though STA3 cannot eavesdrop on RTS frames from STA1. In other words, if STA3 can eavesdrop on one or more RTS or CTS frames from either STA1 or STA2, STA3 can set the NAV accordingly. When STA3 receives a new frame before the NAV timer expires, STA3 can update the NAV timer using the duration information included in the new frame. STA3 does not attempt channel access until the NAV timer expires.

[0096] When STA1 receives a CTS frame from STA2, STA1 can send a data frame to STA2 after SIFS, starting from the time point when the CTS frame reception is complete. When STA2 successfully receives the data frame, STA2 can send an ACK frame to STA1 after SIFS as a response to the data frame. When the NAV timer expires, STA3 can determine whether the channel is in use through carrier sensing. If STA3 determines that the channel is not in use by other terminals during DIFS after the NAV timer expires, STA3 can attempt channel access after the contention window (CW) for random backoff has passed.

[0097] Figure 6 This is a diagram illustrating an example of a frame structure that can be used in a WLAN system to which this disclosure may be applied.

[0098] Using instructions or primitives (meaning a set of instructions or parameters) from the MAC layer, the PHY layer can prepare the MAC PDU (MPDU) to be transmitted. For example, when the PHY layer receives a command from the MAC layer requesting the start of transmission, it switches to transmit mode, configures the information (e.g., data) provided by the MAC layer in the form of a frame, and transmits it. Additionally, when the PHY layer detects a valid preamble in a received frame, it monitors the preamble header and sends a command to the MAC layer notifying the PHY layer of the start of reception.

[0099] In this way, information transmission / reception in a wireless LAN system is performed in the form of frames, and for this purpose, the PHY layer Protocol Data Unit (PPDU) format is defined.

[0100] A basic PPDU can include a Short Training Field (STF), a Long Training Field (LTF), a Signal (SIG) field, and a Data field. The most basic PPDU format (e.g., Figure 7 The non-HT (High Throughput) fields shown can consist solely of a Traditional-STF (L-STF), Traditional-LTF (L-LTF), Traditional-SIG (L-SIG) field, and a data field. Additionally, depending on the PPDU format type (e.g., HT mixed format PPDU, HT green format PPDU, VHT (Very High Throughput) PPDU, etc.), additional (or different types) RL-SIG, U-SIG, non-traditional SIG fields, non-traditional STF, non-traditional LTF (i.e., xx-SIG, xx-STF, xx-LTF (e.g., xx is HT, VHT, HE, EHT, etc.)) can be included between the L-SIG field and the data field.

[0101] STF is a signal used for signal detection, automatic gain control (AGC), diversity selection, precise time synchronization, etc., while LTF is a signal used for channel estimation and frequency error estimation. STF and LTF can be referred to as signals used for synchronization and channel estimation in the OFDM physical layer.

[0102] The SIG field can include various information related to PPDU transmission and reception. For example, the L-SIG field consists of 24 bits and can include a 4-bit rate field, a 1-bit reserved bit, a 12-bit length field, a 1-bit parity field, and a 6-bit tail field. The RATE field can include information about the modulation and coding rate of the data. For example, the 12-bit length field can include information about the length or duration of the PPDU. For example, the value of the 12-bit length field can be determined based on the type of PPDU. For example, for non-HT, HT, VHT, or EHT PPDUs, the value of the length field can be determined to be a multiple of 3. For example, for HE PPDUs, the value of the length field can be determined to be a multiple of 3 + 1 or a multiple of 3 + 2.

[0103] The data field may include a service field, a physical layer service data unit (PSDU), and PPDU tail bits, and may also include padding bits if necessary. Some bits of the service field can be used for synchronization of the descrambler at the receiver. The PSDU corresponds to the MAC PDU defined in the MAC layer and may include data generated / used in the upper layer. The PPDU tail bits can be used to return the encoder to a 0 state. Padding bits can be used to adjust the length of the data field by predetermined units.

[0104] 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). MAC frames can be composed of MAC PDUs and transmitted / received via PSDUs in the data portion of the PPDU format.

[0105] The MAC header includes a frame control field, a duration / ID field, and an address field. The frame control field can include control information required for frame transmission / reception. The duration / ID field can be set to the time used to transmit the corresponding frame, etc. For details on the sequence control, QoS control, and HT control subfields of the MAC header, refer to the IEEE 802.11 standard document.

[0106] The Narrow Data PPDU (NDP) format refers to a PPDU format that does not include the data field. In other words, NDP is a frame format that includes the PPDU preamble of the general PPDU format (i.e., the L-STF, L-LTF, L-SIG fields and other non-traditional SIG, non-traditional STF, and non-traditional LTF (if present)) and does not include the remaining part (i.e., the data field).

[0107] Figure 7 This is a diagram illustrating an example of a PPDU as defined in the IEEE 802.11 standard of this disclosure.

[0108] Various types of PPDUs have been used in standards such as IEEE 802.11a / g / n / ac / ax. The basic PPDU format (IEEE 802.11a / g) includes L-LTF, L-STF, L-SIG, and a data field. The basic PPDU format can also be referred to as a non-HT PPDU format (such as...). Figure 7 (as shown in (a)).

[0109] Compared to the basic PPDU format, the HT PPDU format (IEEE 802.11n) additionally includes the HT-SIG, HT-STF, and HT-LFT fields. Figure 7 The HT PPDU format shown in (b) can be referred to as the HT hybrid format. Furthermore, an HT green format PPDU can be defined, and this corresponds to a format consisting of HT-GF-STF, HT-LTF1, HT-SIG, one or more HT-LTFs and data fields, excluding L-STF, L-LTF, and L-SIG (not shown).

[0110] Compared to the basic PPDU format, examples of the VHT PPDU format (IEEE 802.11ac) additionally include VHTSIG-A, VHT-STF, VHT-LTF, and VHT-SIG-B fields (such as...).Figure 7 (as shown in (c)).

[0111] Compared to the basic PPDU format, examples of the HE PPDU format (IEEE 802.11ax) additionally include repeated L-SIG (RL-SIG), HE-SIG-A, HE-SIG-B, HE-STF, HE-LTF, and Packet Extension (PE) fields (such as...). Figure 7 (as shown in (d)). Some fields can be excluded, or their lengths can vary depending on the detailed examples of the HE PPDU format. For example, the HE-SIG-B field is included in the HE PPDU format for multi-user (MU), but not in the HE PPDU format for single-user (SU). Furthermore, the HE-Trigger-Based (TB) PPDU format does not include HE-SIG-B, and the length of the HE-STF field can vary up to 8 μs. The Extended Range (HE ER) SU PPDU format does not include the HE-SIG-B field, and the length of the HE-SIG-A field can vary up to 16 μs. For example, RL-SIG can be configured to be the same as L-SIG. Based on the presence of RL-SIG, the receiving STA can determine whether the received PPDU is an HE PPDU or an EHT PPDU, which will be described later.

[0112] EHT PPDU format can include Figure 7 EHT MU (Multi-user) in (e) and Figure 7 The EHT TB (trigger-based) PPDU in (f). The EHT PPDU format is similar to the HE PPDU format in that it includes RL-SIG following L-SIG, but it can include U (generic)-SIG, EHT-SIG, EHT-STF and EHT-LTF following RL-SIG.

[0113] Figure 7 In (e), the EHT MU PPDU corresponds to a PPDU carrying one or more data (or PSDU) for one or more users. That is, the EHT MU PPDU can be used for both SU and MU transmissions. For example, the EHT MU PPDU can correspond to a PPDU for one or more receiving STAs.

[0114] Compared to EHT MU PPDU, Figure 7 In (f), the EHT-SIG is omitted from the EHT TB PPDU. The STA that receives the trigger for UL MU transmission (e.g., trigger frame or trigger response schedule (TRS)) can perform UL transmission based on the EHT TB PPDU format.

[0115] The L-STF, L-LTF, L-SIG, RL-SIG, U-SIG (general signal), and EHT-SIG fields can be encoded and modulated so that even conventional STAs can attempt demodulation and decoding, and can be mapped based on a determined subcarrier frequency interval (e.g., 312.5 kHz). These can be referred to as pre-EHT modulated fields. Next, the EHT-STF, EHT-LTF, data, and PE fields can be encoded and modulated to be demodulated and decoded by an STA that has successfully decoded a non-conventional SIG (e.g., U-SIG and / or EHT-SIG) and obtained the information contained in that field, and can be mapped based on a determined subcarrier frequency interval (e.g., 78.125 kHz). These can be referred to as EHT modulated fields.

[0116] Similarly, in the HE PPDU format, the L-STF, L-LTF, L-SIG, RL-SIG, HE-SIG-A, and HE-SIG-B fields can be referred to as pre-HE modulation fields, and the HE-STF, HE-LTF, data, and PE fields can be referred to as HE modulation fields. Additionally, in the VHT PPDU format, the L-STF, L-LTF, L-SIG, and VHT-SIG-A fields can be referred to as non-VHT modulation fields, and the VHT STF, VHT-LTF, VHT-SIG-B, and data fields can be referred to as VHT modulation fields.

[0117] Included Figure 7 In the EHT PPDU format, U-SIG can be configured based on, for example, two symbols (e.g., two consecutive OFDM symbols). Each symbol used for U-SIG (e.g., an OFDM symbol) can have a duration of 4 μs, and U-SIG can have a total duration of 8 μs. Each symbol of U-SIG can be used to transmit 26 bits of information. For example, each symbol of U-SIG can be transmitted and received based on 52 data tones and 4 pilot tones.

[0118] U-SIGs can be constructed in 20MHz units. For example, if an 80MHz PPDU is constructed, U-SIGs can be replicated. That is, the same four U-SIGs can be included in an 80MHz PPDU. PPDUs with bandwidths exceeding 80MHz can include different U-SIGs.

[0119] For example, A uncoded bits can be sent via U-SIG. The first symbol of U-SIG (e.g., U-SIG-1 symbol) can send the first X bits of the total A-bit information, and the second symbol of U-SIG (e.g., U-SIG-2 symbol) can send the remaining Y bits of the total A-bit information. The A-bit information (e.g., 52 uncoded bits) may include a CRC field (e.g., a 4-bit field) and a tail field (e.g., a 6-bit field). For example, the tail field can be used to terminate the lattice structure of the convolutional decoder and can be set to 0.

[0120] Bit information sent via U-SIG can be divided into version-independent bits and version-dependent bits. For example, U-SIG can be included in... Figure 7 The new PPDU format (e.g., UHR PPDU format) not shown in the figure, and may be included in the format of the U-SIG field included in the EHT PPDU format and the format of the U-SIG field included in the UHR PPDU format, the version-independent bits may be the same, and some or all of the version-related bits may be different.

[0121] For example, the size of the version-independent bits in U-SIG can be fixed or variable. Version-independent bits can be assigned only to the U-SIG-1 symbol, or to both the U-SIG-1 and U-SIG-2 symbols. Version-independent bits and version-dependent bits can be referred to by various names, such as first control bits and second control bits.

[0122] For example, the version-independent bits of U-SIG may include a 3-bit Physical Layer Version Identifier (PHY Version Identifier), which can indicate the PHY version (e.g., EHT, UHR, etc.) of the transmitted / received PPDU. The version-independent bits of U-SIG may include a 1-bit UL / DL Flag field. The first value of the 1-bit UL / DL Flag field is related to UL communication, and the second value is related to DL communication. The version-independent bits of U-SIG may include information about the length of the Transmission Opportunity (TXOP) and information about the BSS color ID.

[0123] For example, the version-related bits of U-SIG may include information that directly or indirectly indicates the type of PPDU (e.g., SUPPDU, MU PPDU, TB PPDU, etc.).

[0124] Information required for PPDU transmission and reception can be included in the U-SIG. For example, the U-SIG may also include information about bandwidth, information about the MCS technique applied to non-traditional SIGs (e.g., EHT-SIG or UHR-SIG), information indicating whether DCM (dual-carrier modulation) techniques (e.g., techniques used to achieve effects similar to frequency diversity by reusing the same signal on two subcarriers) are applied to non-traditional SIGs, information about the number of symbols used for non-traditional SIGs, and information about whether non-traditional SIGs are generated across the entire frequency band.

[0125] Some of the information required for PPDU transmission and reception may be included in U-SIG and / or non-traditional SIG (e.g., EHT-SIG or UHR-SIG). For example, information about the type of non-traditional LTF / STF (e.g., EHT-LTF / EHT-STF or UHR-LTF / UHR-STF), the length of the non-traditional LTF and the CP (cyclic prefix) length, the GI (guard interval) applicable to the non-traditional LTF, the preamble punching information applicable to the PPDU, and the resource unit (RU) allocation may be included only in U-SIG, only in non-traditional SIG, or may be indicated by a combination of information included in U-SIG and information included in non-traditional SIG.

[0126] Preamble puncturing can represent the transmission of a PPDU where no signal is present in one or more frequency units within the bandwidth of the PPDU. For example, the size of the frequency unit (or the resolution of the preamble puncturing) can be defined as 20MHz, 40MHz, etc. For example, preamble puncturing can be applied to PPDU bandwidths of a predetermined size or larger.

[0127] exist Figure 7 In the examples, non-traditional SIGs such as HE-SIG-B and EHT-SIG can include control information for receiving STAs. Non-traditional SIGs can be transmitted on at least one symbol, and a symbol can have a length of 4 μs. Information regarding the number of symbols used for EHT-SIGs can be included in previous SIGs (e.g., HE-SIG-A, U-SIG, etc.).

[0128] Non-traditional SIGs such as HE-SIG-B and EHT-SIG can include both public and user-specific fields. These public and user-specific fields can be encoded separately.

[0129] In some cases, the common field can be omitted. For example, in compressed mode using non-OFDMA (Orthogonal Frequency Division Multiple Access), the common field can be omitted, and multiple STAs can receive PPDUs (e.g., the data field of the PPDU) through the same frequency band. In uncompressed mode using OFDMA, multiple users can receive PPDUs (e.g., the data field of the PPDU) through different frequency bands.

[0130] The number of user-specific fields can be determined based on the number of users. A user block field can include up to two user fields. Each user field can be associated with either a MU-MIMO allocation or a non-MU-MIMO allocation.

[0131] The common fields may include CRC bits and tail bits, where the length of the CRC bits can be determined to be 4 bits, and the length of the tail bits can be determined to be 6 bits and set to 000000. The common fields may include RU allocation information. RU allocation information may include information about the locations of RUs assigned to multiple users (i.e., multiple receiving STAs).

[0132] An RU can include multiple subcarriers (or tones). RUs can be used when transmitting signals to multiple STAs based on OFDMA technology. Additionally, RUs can be defined even when transmitting signals to a single STA. Resources can be allocated in units of RUs for non-traditional STFs, non-traditional LTFs, and data fields.

[0133] The appropriate RU size can be defined based on the PPDU bandwidth. RUs can be defined the same or different for the applied PPDU format (e.g., HEPPDU, EHT PPDU, UHR PPDU, etc.). For example, in the case of an 80MHz PPDU, the RU layout for HEPPDU and EHT PPDU can be different. The appropriate RU size, number and location of RUs, DC (direct current) subcarrier locations and numbers, empty subcarrier locations and numbers, guard subcarrier locations and numbers, etc., for each PPDU bandwidth can be referred to as the tone scheme. For example, a tone scheme for high bandwidth can be defined as multiple iterations of a low-bandwidth tone scheme.

[0134] RUs of various sizes can be defined as 26-tone RUs, 52-tone RUs, 106-tone RUs, 242-tone RUs, 484-tone RUs, 996-tone RUs, 2×996-tone RUs, 3×996-tone RUs, etc. MRUs (Multiple RUs) differ from multiple individual RUs and correspond to a group of subcarriers composed of multiple RUs. For example, an MRU can be defined as 52+26-tone, 106+26-tone, 484+242-tone, 996+484-tone, 996+484+242-tone, 2×996+484-tone, 3×996-tone, or 3×996+484-tone. Furthermore, the multiple RUs constituting an MRU can be consecutive or non-consecutive in the frequency domain.

[0135] The specific size of the RU can be reduced or expanded. Therefore, the specific size of each RU in this disclosure (i.e., the number of corresponding tones) is not limiting but illustrative. In addition, in this disclosure, the number of RUs can vary depending on the RU size within a predetermined bandwidth (e.g., 20MHz, 40MHz, 80MHz, 160MHz, 320MHz...).

[0136] Figure 7 The names of each field in the PPDU format are exemplary, and the scope of this disclosure is not limited to these names. Furthermore, the examples in this disclosure can be applied to… Figure 7 The PPDU format shown and based on Figure 7 A new PPDU format that excludes some fields and / or adds some fields, based on the PPDU format.

[0137] Trigger frame

[0138] Figure 8 This is a diagram illustrating an example format of the trigger frame that can be applied according to this disclosure.

[0139] A trigger frame can allocate resources for sending at least one TB PPDU and request the TB PPDU to be sent. The trigger frame may also include other information required by the STA that sends the TB PPDU in response. The trigger frame may include common info and user info list fields in the frame body.

[0140] The public information field may include information that is publicly applied to at least one TB PPDU sent by the trigger frame request, such as trigger type, UL length, whether there are subsequent trigger frames (e.g., more TFs), whether channel sensing (CS) is required, UL bandwidth (BW), etc. Figure 8 The EHT variant public information field format is illustrated as an example.

[0141] The 4-bit trigger type subfield can have values ​​from 0 to 15. Among them, the values ​​0, 1, 2, 3, 4, 5, 6, and 7 of the trigger type subfield are defined to correspond to Basic, BFRP (Beamforming Report Polling), MU-BAR (Multi-User Block Acknowledgment Request), MU-RTS (Multi-User Request Sending), BSRP (Buffer Status Report Polling), GCR (Multicast with Retry) MU-BAR, BQRP (Bandwidth Query Report Polling), and NFRP (NDP Feedback Report Polling), and values ​​8-15 are defined as reserved.

[0142] In public information, the trigger-related public information subfields can include information selectively included based on the trigger type.

[0143] Special user information fields can be included in the trigger frame. These fields do not include user-specific information, but do include extended public information not provided in the public information fields.

[0144] The user information list includes at least 0 user information fields. Figure 8 The EHT variant user information field format is illustrated as an example.

[0145] The AID12 subfield essentially indicates that it is a user information field for an STA with a corresponding AID. Additionally, when an AID12 field has a predetermined specific value, it can be used for other purposes, such as allocating Random Access (RA)-RU or configuring it as a special user information field. A special user information field is a user information field that does not include user-specific information but includes extended public information not provided in the public information field. For example, a special user information field can be identified by the AID12 value 2007, and the special user information field flag subfield in the public information field can indicate whether a special user information field is included.

[0146] The RU allocation subfield can indicate the size and location of the 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 public information field, etc.

[0147] Multi-link operation

[0148] The following describes multi-link operation supported by STA according to this disclosure.

[0149] The STAs (AP STAs and / or non-AP STAs) described in this disclosure can support multi-link (ML) communication. ML communication can refer to communication that supports multiple links.

[0150] Links associated with ML communication can include channels (e.g., 20 / 40 / 80 / 160 / 240 / 320MHz channels) in the frequency bands (e.g., 2.4 GHz band, 5 GHz band, 6 GHz band, etc.) where the STA operates. Multiple links for ML communication can be configured in various ways. For example, multiple links for ML communication supported by a single STA can belong to the same frequency band or different frequency bands. For example, multiple links can include multiple frequency bands; that is, multiple links can represent links spanning multiple frequency bands, or multiple links within a single frequency band.

[0151] In addition, each link can correspond to a frequency unit of a predetermined size (e.g., channel, sub-channel, RU, etc.). Furthermore, all or part of multiple links can be frequency units of the same size, or they can be frequency units of different sizes.

[0152] When a STA supports multiple links, the transmitting or receiving device supporting each link can operate as a logical STA. In other words, an MLD refers to a device that is a logical entity with at least one affiliated STA and a single MAC Service Access Point (SAP) for a MAC data service and logical link control (LLC).

[0153] Figure 9 Exemplary MLD structures that can be applied to this disclosure are illustrated.

[0154] refer to Figure 9 A STA MLD may have one or more subordinate STAs (e.g., STA1, STA2, ..., STAn), and associated with these, may have one or more links (e.g., link1, link2, ..., linkM).

[0155] Here, a STA belonging to a STA MLD can correspond to a non-AP STA or an AP STA. In this respect, a non-AP MLD means that each STA belonging to the corresponding MLD is a non-AP STA MLD. A multi-radio non-AP MLD means a non-AP MLD that supports receiving or exchanging frames on at least one link at a time. An AP MLD means that each STA belonging to the corresponding MLD is an AP STA MLD.

[0156] A non-AP MLD refers to an MLD in which each STA belonging to the corresponding 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 at least one link at a time. An AP MLD refers to an MLD in which each STA belonging to the corresponding MLD is an AP STA.

[0157] Multi-link operation (MLO) enables non-AP MLDs to discover, authenticate, and associate with AP MLDs and establish multiple links. Based on the supported capabilities exchanged during the association process, each link can enable channel access and frame switching between a non-AP MLD and an AP MLD. STAs belonging to an MLD can independently select and manage their capabilities and operating parameters from other STAs belonging to the same MLD.

[0158] Through the multi-link establishment process, the AP MLD and / or non-AP MLD can send or receive link-related information that can be supported by the corresponding MLD. Link-related information may include at least one of the following: whether it is simultaneous transmit and receive (STR) operation that can be sent or received simultaneously on multiple links or non-simultaneous transmit and receive (NSTR) operation that cannot be sent or received simultaneously; information about the number / upper limit of UL / DL links; information about the location / band / resources of UL / DL links; information about the available or preferred frame types (e.g., management, control, data) in at least one UL / DL link; information about the available or preferred ACK policies in at least one UL / DL link; or information about the service identifier (TID) available in at least one UL / DL link supported by the corresponding MLD.

[0159] An AP MLD (e.g., an NSTR mobile AP MLD) can configure one of multiple links as the primary link. An AP MLD can perform beacon frames, probe response frames, and group-addressed data frames only on the primary link. The remaining links among the multiple links can be referred to as non-primary links. An AP MLD operating on a non-primary link can operate without sending beacon frames or probe response frames. Additionally, a non-AP MLD can perform frame switching only on the primary link during authentication, (re)association, and the 4-way handshake.

[0160] When at least one Service Identifier (TID) is mapped to a corresponding link through a multi-link establishment process, the established link can be defined as enabled, and when no TID is mapped to a corresponding link, the established link can be defined as disabled. Unless admission control is used, a TID should always be mapped to at least one established link. Essentially, a TID is mapped to all established links, therefore all established links can be activated.

[0161] When a link is activated, it can be used for frame switching based on the power status of the non-AP STA operating on that link. Only MSDUs or A-MSDUs with a TID mapped to the active link can be transmitted on that link. Management and control frames can be transmitted only on the active link.

[0162] When a link is deactivated, the corresponding link may not be used for frame switching by including management frames for both DL and UL.

[0163] During the multi-link establishment process, TID-to-link mapping can be used to indicate the activation / deactivation of each link. TID-to-link mapping can be performed in the default mapping mode or / and the negotiated mapping mode.

[0164] One of the STAs belonging to the MLD can provide information about at least one link other than its own link for use in multi-link discovery (e.g., obtaining information about multiple links including the corresponding link on one link) or multi-link establishment (e.g., simultaneously associating on multiple links by exchanging association request / response frames on one link). To provide this information, a multi-link (ML) element can be defined.

[0165] Figure 10 The structure of the ML element to which this disclosure can be applied is illustrated by way of example.

[0166] exist Figure 10 In the ML element (or ML information element (IE)) of (a), the element ID field and the element ID extension field may have specific values ​​indicating that they are ML elements (e.g., 255 and 107), and the length field may have a value indicating the length of the remaining fields (e.g., octet units) other than the element ID field and the length field.

[0167] Figure 10 (b) shows Figure 10 An exemplary format for the multilink control field in (a) is provided. For example, the multilink control field is defined as having a size of two octets and may include a 3-bit type subfield, a 1-bit reserved bit, and a 12-bit presence bitmap subfield. The type subfield may have a value indicating one of the types such as basic, probe request, reconfiguration, tunneled direct link establishment (TDLS), priority access, etc. The presence bitmap subfield indicates the presence of various subfields within the public information field and may be defined in different formats depending on various variants of the ML element (or the types described above).

[0168] Figure 10 (c) shows Figure 10The exemplary format of the public information field in (a) is as follows. The public information field may contain information common to all links based on the ML element. The public information field may be defined as having a variable size. The public information length subfield may indicate the number of octets included in the public information field (including one octet of the public information length subfield). The 6-octet MLD MAC address subfield may have a value specifying the MAC address of the MLD to which the STA sending the basic ML element belongs. Furthermore, the link ID information subfield, BSS parameter change count subfield, media synchronization delay information subfield, enhanced multilink (EML) capability subfield, MLD capability and operation subfield, AP MLD ID subfield, extended MLD capability and operation subfield, etc., may be included in the public information field or may not be included in the public information field.

[0169] Figure 10 The link information field in (a) is defined as having a variable size and may include link-specific information, and may optionally exist. The link information field may contain information applied independently to each link based on the ML element. When the link information field exists, it may include at least one sub-element. The format and order of the sub-elements can be defined in various ways. As an example of the optional sub-element ID of the basic variant ML element, the value of sub-element ID 0 corresponds to the name of each STA profile and is extensible, and the value of sub-element ID 221 corresponds to a vendor-specific name, and whether it is extensible can be determined by the vendor, and the value of sub-element ID 254 corresponds to the name of the fragment and is not extensible, and the remaining values ​​1-220, 222-253, and 255 may be reserved.

[0170] Figure 10 (d) illustrates an exemplary format for each STA profile sub-element. Each STA profile sub-element may include a 1-octet sub-element ID sub-field, a 1-octet length sub-field, a 2-octet STA control sub-field, a variable-size STA information sub-field, and a variable-size STA profile sub-field. The STA control sub-field may include information such as the link ID, whether a complete profile is included, and whether a STA MAC address is present. The STA information sub-field may include information such as the STA MAC address. Depending on whether the reported STA is an AP STA or a non-AP STA, the STA profile sub-field may include information included in the probe response or probe request frame body, information included in the (re)association response or (re)association request frame body, etc.

[0171] Figure 10The format of ML elements in the MLD is descriptive, and the order, name, size, etc. of fields / subfields can be changed. Additional fields / subfields can be further defined, and some fields / subfields can be excluded. In other words, the public information field can include public information between STAs in the MLD, and the link information field can include specific information about each STA / link (e.g., in the per STA profile sub-element that includes the link ID corresponding to the corresponding STA).

[0172] Link indication related to enhanced multi-link single radio (EMLSR) mode

[0173] Regarding the aforementioned multi-link-based operations, this disclosure describes specific methods for indicating links associated with EMLSR modes.

[0174] Regarding EMLSR mode, a STA MLD can perform a listening operation on multiple links as an initial operation. In this respect, a link with EMLSR mode enabled can be referred to as an EMLSR link. Upon receiving an initial control frame (e.g., MU-RTS trigger frame (TF), BSRP TF, etc.) on a specific link through a listening operation, a STA MLD can perform frame exchange with another STA MLD on the link using a single radio.

[0175] Figure 11 An example is shown of an EMLSR-based operation that can be applied to this disclosure.

[0176] refer to Figure 11 In EMLSR mode, a non-AP MLD can perform listening operations on multiple links. Subsequently, the AP MLD can send a MU-RTS trigger frame, and the non-AP MLD can receive a MU-RTS trigger frame on one of the EMLSR links. In response, the non-AP MLD can send a CTS frame (a response frame to the MU-RTS trigger frame) to the AP MLD on that link. Then, the non-AP MLD can perform frame exchange with the AP MLD on that link.

[0177] Information related to the aforementioned EMLSR pattern can be obtained through ML elements (e.g., Figure 10 (The ML element shown in (a) is used to provide this).

[0178] For example, information related to the EMLSR schema can be provided through the EML Capability subfield included in the public information field within the ML element.

[0179] Figure 12 An example is provided of the format of an EML capability subfield included in a public information field within an ML element to which this disclosure may be applied.

[0180] refer toFigure 12 The EML capability subfield format can include information related to the EMLSR mode and information related to the Enhanced Multi-Link Multi-Radio (EMLMR) mode. Specifically, the EML capability subfield format can include an EMLSR support subfield, an EMLSR padding delay subfield, an EMLSR transition delay subfield, an EMLMR support subfield, an EMLMR delay subfield, and a handover timeout subfield.

[0181] Here, the EMLSR support subfield indicates whether the MLD described in the ML element supports EMLSR operation and can consist of 1 bit. Additionally, the EMLSR padding delay subfield indicates the minimum MAC padding duration requested by the non-AP MLD for the initial control preamble. Furthermore, the EMLSR handover delay subfield indicates the handover delay required for a non-AP MLD to switch from PPDU exchange operation on one of the active links (i.e., the link with EMLSR mode enabled) to a listening operation on the active link. Finally, the handover timeout subfield indicates the timeout value used for EML operation mode notification frame exchange in EMLSR and EMLMR modes.

[0182] In other words, the public information field within the ML element can provide information about whether EMLSR operations are supported through the EML capability subfield, and if supported, it can provide specific information related to EMLSR operations (e.g., EMLSR fill delay).

[0183] Additionally, as mentioned above, the link information field within an ML element can consist of one or more per-STA profile sub-elements (e.g., Figure 10 Each STA profile element shown in (d) is composed of sub-elements.

[0184] Figure 13 Examples include the STA control field format and STA information field format included in each STA profile sub-element where this disclosure may be applied.

[0185] refer to Figure 13 (a) The STA control field format within each STA profile sub-element may include a link ID sub-field, a complete profile sub-field, a STA MAC address presence sub-field, a beacon interval presence sub-field, a TSF offset presence sub-field, a DTIM information presence sub-field, a non-simultaneous transmit and receive (NSTR) link pair presence sub-field, an NSTR bitmap size sub-field, and a BSS parameter change count presence sub-field.

[0186] refer to Figure 13(b) The format of the STA information field within each STA profile sub-element may include the STA information length sub-field, STA MAC address sub-field, beacon interval sub-field, TSF offset sub-field, DTIM information sub-field, NSTR indicator bitmap sub-field, and BSS parameter change count sub-field.

[0187] At this point, the link ID can be used to map each perSTA profile to information specific to each link. Specifically, when a link is configured as a link pair with another link, each perSTA profile can indicate whether the link pair is operating in NSTR operation / mode via bitmap information (e.g., an NSTR indicator bitmap). For example, a bit set to "1" in the bitmap information can indicate that the link pair corresponds to an NSTR link pair operating in NSTR operation / mode, and a bit set to "0" in the bitmap information can indicate that the link pair corresponds to a STR link pair operating in STR operation / mode. Additionally, if the bitmap information is not present in the perSTA profile, it may mean that all link pairs are operating in STR operation / mode.

[0188] In this regard, when performing the multilink establishment procedure (i.e., exchanging association request / response frames), information about STR link pairs and NSTR link pairs is indicated by the ML element of each frame, but information about EMLSR links (and / or EMLSR link pairs) is not indicated. The EML Operation Mode Notification (OMN) frame, along with EMLSR mode enablement, can indicate the EMLSR links used for EMLSR operation as described above after the multilink establishment procedure.

[0189] Therefore, EMLSR links may not always operate in STR operation / mode, where frame switching can occur simultaneously on multiple links regardless of the eavesdropping operation in EMLSR, potentially leading to ambiguity. That is, for a link pair indicated as operating in STR operation / mode during multi-link establishment, a STA MLD knowing that the link pair is for STR operation / mode may not perform basic eavesdropping operations before activating EMLSR mode. In other words, because a STA MLD with a set of links that can operate only in EMLSR mode may not operate in STR operation / mode until EMLSR mode is activated, the STA MLD may not perform frame switching correctly / appropriately.

[0190] To address the aforementioned issues, this disclosure presents a method for indicating / providing information about links (hereinafter referred to as EMLSR links) for EMLSR operation / mode through detailed examples.

[0191] In embodiments of this disclosure, the detailed name may be replaced / changed with other names, and the STA may include an AP STA or a non-AP STA.

[0192] Embodiment 1

[0193] This embodiment relates to a method for indicating / providing information about an EMLSR link through a link information field within an ML element.

[0194] To address this, a new EMLSR indicator bitmap field can be defined. For example, an EMLSR indicator bitmap field, such as the NSTR indicator bitmap field of the link information field within an ML element, can be utilized.

[0195] An EMLSR indicator bitmap can be defined as indicating whether the links in the indicator bitmap (i.e., the links indicated by the link IDs included in the STA control field of the ML element) and the links corresponding to each bit constituting the bitmap can operate only in EMLSR mode. Specifically, the bits constituting the EMLSR indicator bitmap can indicate pairs / sets of links in the indicator bitmap and links that support EMLSR mode. For example, if the value of at least one bit among a plurality of bits constituting the EMLSR indicator bitmap is set to a specific value (e.g., the value "1"), then a pair / set consisting of the links indicative of the EMLSR indicator bitmap and at least one other link corresponding to that at least one bit can correspond to a pair / set of links that only support EMLSR mode.

[0196] In other words, since a link consisting of each link pair according to the indicated bits can operate as an EMLSR link only, frame switching should always be initiated during a listening operation via an initial control frame.

[0197] In this regard, for link pairs that are indicated as EMLSR links by the aforementioned EMLSR indicator bitmap (e.g., link pairs indicated by a specific value (e.g., value '1') in the EMLSR indicator bitmap), the values ​​for the corresponding link pairs in the NSTR indicator bitmap can be ignored.

[0198] Figure 14 This illustrates information about an EMLSR link indicated / provided via a link information field according to an embodiment of this disclosure.

[0199] refer to Figure 14 (a) Figure 13 The STA control field format shown in (a) can be supplemented with an EMLSR link pair existence subfield indicating the existence of an EMLSR link pair (i.e., the existence of an EMLSR indicator bitmap) and an EMLSR bitmap size subfield indicating the size of the EMLSR bitmap.

[0200] In this regard, the EMLSR bitmap size subfield can be defined to indicate whether it is one octet or two octets, but is not limited to this. Furthermore, considering the case of implementing EMLSR links with a finite number of links, the EMLSR bitmap size subfield can be defined to indicate 2 bits, 4 bits, etc.

[0201] Reference Figure 14 (b) can add the above EMLSR indicator bitmap field to Figure 13 The STA information field format shown in (b) is as follows.

[0202] In this regard, if the MLD receiving the corresponding ML element is a single-radio MLD, the EMLSR indication bitmap field may not exist. In the case of a single-radio MLD, the EMLSR indication bitmap is unnecessary because the value of the maximum number of simultaneous links subfield in the MLD capability and operation subfields included in the common information field of the ML element is 0. Additionally or alternatively, the EMLSR indication bitmap field may not exist even if no link is operating in EMLSR mode.

[0203] Figure 15 A detailed example of an EMLSR indicator bitmap included in a link information field according to an embodiment of the present disclosure is illustrated.

[0204] refer to Figure 15 MLD can operate on three links (i.e., link 0, link 1 and link 2), and it is assumed that MLD can operate in EMLSR mode only on link 0 and link 1.

[0205] In this case, the EMLSR indicator bitmap is based on the per-STA profile of link 0. For example, in the EMLSR indicator bitmap, the first bit (e.g., bit 0) may be associated with link 0, the second bit (e.g., bit 1) may be associated with link 1, and the third bit (e.g., bit 2) may be associated with link 2.

[0206] Specifically, in Figure 15 In the example shown, the second bit corresponding to the link pair consisting of link ID 0 and link ID 1 in the EMLSR indicator bitmap can indicate a specific value (e.g., the value '1'). For example, if the size of the EMLSR indicator bitmap is indicated as one octet, the bitmap can be represented as "010000000". As another example, if the size of the EMLSR indicator bitmap is indicated as two octets, the bitmap can be represented as "01000000000000000".

[0207] In this regard, the operation in a link pair consisting of link 0 and link 2 can be determined by the NSTR indicator bitmap field in the STA information field format. Furthermore, even if information about the relationship between link 0 and link 1 is indicated by the NSTR indicator bitmap, this information can be ignored based on the EMLSR indicator bitmap.

[0208] Embodiment 2

[0209] This implementation relates to a method for indicating / providing information for an EMLSR link via a public information field within an ML element.

[0210] The method proposed in Implementation 1 may incur significant overhead because information for EMLSR links is indicated through each perSTA profile. To reduce this overhead, a method could be considered for indicating / providing information for EMLSR links via a common information field within an ML element.

[0211] To address this, a new EMLSR indicator bitmap field can be defined. Here, the size of the EMLSR indicator bitmap field can be predefined to a certain value (e.g., 1 octet, 2 octets, etc.).

[0212] Only EMLSR mode can operate between links indicated by the EMLSR indicator bitmap. In other words, the bitmap can be defined as an indication of the set of links that can operate only in EMLSR mode. For example, if the value of at least one bit among the bits constituting the EMLSR indicator bitmap is set to a specific value (e.g., '1'), then the set of links consisting of at least one link corresponding to that at least one bit can correspond to the set of links that only support that mode.

[0213] In the case of the EMLSR indicator bitmap described in Implementation 1, each bit can indicate whether one link and another link (i.e., link pair) can operate only in EMLSR mode. In contrast, the EMLSR indicator bitmap described in Implementation 2 can indicate only the link indicated by a specific value (e.g., value '1') can operate only in EMLSR mode, rather than indicating each link pair.

[0214] In other words, since a set of links based on the indicated bits (e.g., a link indicated by the value '1') can operate as EMLSR links only, frame switching should always be initiated via the initial control frame in the listening operation.

[0215] In this regard, for links that are indicated as EMLSR links via the EMLSR indicator bitmap (e.g., links indicated by the value '1' in the EMLSR indicator bitmap), the values ​​for the corresponding links in the NSTR indicator bitmap can be ignored.

[0216] The EMLSR indicator bitmap can be included as a subfield within the public information field. Additionally or alternatively, the EMLSR indicator bitmap can be included within the EML capability subfield or the extended MLD capability and operation subfield within the public information field. In this case, to reduce overhead, information regarding the EMLSR bitmap size, as in Embodiment 1, can be included with the EMLSR indicator bitmap. Figure 1 It is included in the public information field.

[0217] Figure 16 This illustrates information for an EMLSR link indicated / provided via a public information field according to an embodiment of this disclosure.

[0218] refer to Figure 16 ,for Figure 12 The EML capability subfield format shown can be used to add an EMLSR indicator bitmap field as described above.

[0219] In this regard, if the MLD receiving the corresponding ML element is a single-radio MLD, the EMLSR indication bitmap field may not exist. In the case of a single-radio MLD, the EMLSR indication bitmap is unnecessary because the value of the maximum number of simultaneous links subfield in the MLD capability and operation subfields included in the common information field of the ML element is 0. Additionally or alternatively, the EMLSR indication bitmap field may not exist even if EMLSR mode is not supported. Additionally or alternatively, the presence or absence of the EMLSR indication bitmap field can be indicated by a field indicating presence or absence as described in Embodiment 1 (e.g., the EMLSR link pair presence subfield).

[0220] Figure 17 A detailed example of an EMLSR indicator bitmap included in a public information field according to an embodiment of the present disclosure is illustrated.

[0221] refer to Figure 17 MLD can operate on three links (i.e., link 0, link 1 and link 2), and it is assumed that MLD can operate in EMLSR mode only on link 0 and link 1.

[0222] For example, in an EMLSR indicator bitmap, the first bit (e.g., bit 0) can be associated with link 0, the second bit (e.g., bit 1) can be associated with link 1, and the third bit (e.g., bit 2) can be associated with link 2.

[0223] Specifically, in Figure 17In the example shown, the first and second bits corresponding to Link ID 0 and Link ID 1 in the EMLSR indicator bitmap can indicate a specific value (e.g., the value '1'). For example, if the size of the EMLSR indicator bitmap is defined / indicated as one octet, the corresponding bitmap can be represented as "11000000". As another example, if the size of the EMLSR indicator bitmap is defined / indicated as two octets, the corresponding bitmap can be represented as "11000000000000000".

[0224] In this regard, operations in link pairs consisting of link 0 and link 2, and link pairs consisting of link 1 and link 2, can be determined by the NSTR indicator bitmap field in the STA information field format. Furthermore, even if information regarding the relationship between link 0 and link 1 is indicated by the NSTR indicator bitmap, this information can be ignored based on the EMLSR indicator bitmap.

[0225] Embodiment 3

[0226] This embodiment relates to a method for indicating that a specific MLD corresponds to an EMLSR MLD in multi-link-based operations.

[0227] Here, EMLSR MLD can refer to STA MLD, where all STAs belonging to STA MLD are configured / instructed to operate only in EMLSR mode on the links they operate on.

[0228] Figure 18 An example is provided of an EML capability subfield within a public information field that includes information indicating that it is an EMLSR MLD, according to an embodiment of this disclosure.

[0229] refer to Figure 18 A new EMLSR-only support subfield can be defined, indicating whether all STAs belonging to / included in the MLD can operate on the link in EMLSR mode only. For example, the EMLSR-only support subfield can consist of 1 bit.

[0230] Additional or alternative land, though Figure 18 The example shows that the EML Capability subfield is included in the Common Information field, but the EML Capability subfield can be included in another subfield within the Common Information field.

[0231] Additionally or alternatively, the EMLSR Support Only subfield may exist / include the EMLSR Indicator Bitmap subfield described above in this disclosure. In this case, if the EMLSR Support Only subfield indicates that the EMLSR MLD corresponds to (e.g., if the EMLSR Support Only subfield is set to the value '1'), the EMLSR Indicator Bitmap subfield may not exist.

[0232] Embodiment 4

[0233] This implementation relates to a method for defining rules for EMLSR operations.

[0234] Specifically, the following operations can be predefined / configured as rules related to EMLSR patterns.

[0235] (Rule 1)

[0236] If an MLD is indicated / set to support EMLSR mode in the EML capability subfield within an ML element (e.g., EMLSR support = 1), then an MLD aware of this can send initial control frames (e.g., MU-RTS trigger frames, BSRP trigger frames, etc.) to the MLD supporting EMLSR mode on all established active links. Based on this, frame exchange between MLDs can be initiated. That is, due to EMLSR mode support, frame exchange is not performed immediately regardless of the information in the NSTR indicator bitmap. However, rule-based operation may degrade performance on links that can be used as STR operations.

[0237] (Rule 2)

[0238] Based on the EMLSR indicator bitmap described above in this disclosure (e.g., the EMLSR indicator bitmap in embodiments 1 / 2 / 3), that is, for information about a link that must operate only in EMLSR mode, at least one of the following operations can be performed.

[0239] For example, in a link that will only operate in EMLSR mode, one or more frames may not be sent after the indication message until EMLSR mode is activated.

[0240] As another example, frame switching can be performed using only one or more links required for operation in EMLSR mode (e.g., an EMLSR indicator bitmap) instead of all links required for operation in EMLSR mode before activating EMLSR mode. Additionally, operation-related information can be indicated. For example, a link ID for a specific link capable of frame switching can be indicated. Additionally or alternatively, additional link bitmap information can be used to indicate the links capable of performing frame switching. For example, in Figure 17In the MLD structure shown, if the link capable of performing frame switching is link 1 and the bitmap size is defined / set to 1 octet, additional link bitmap information '01000000' can be indicated in the common information field.

[0241] In the following, the transmission and reception operations of the STA according to the foregoing embodiments of this disclosure will be described. Here, the STA may correspond to a non-AP STA or an AP, and may correspond to a STA belonging to a multi-link MLD.

[0242] The first MLD that supports EMLSR mode can send a first PPDU to the second MLD. The first PPDU includes information about whether one or more links that are in operation (among multiple links) can operate only in EMLSR mode.

[0243] In this regard, the first PPDU can be sent during the association phase or a subsequent phase. For example, the first PPDU can be included in the association request / response frame.

[0244] Additionally or alternatively, information may be included in the multi-link (ML) element. In this regard, information may be included in a common information field within the ML element. For example, a link bitmap (e.g., an EMLSR link indicator bitmap) may be used to set bits corresponding to links operating only in EMLSR mode to '1'. Additionally or alternatively, this information may be included in the per-STA profile corresponding to each link in the link information field within the ML element. For example, the per-STA profile for link 1 may include a link bitmap (e.g., an EMLSR link indicator bitmap) consisting of one or more bits indicating a pair between link 1 and each other link. Here, each bit may be set to the value '1' to indicate that a link pair consisting of link 1 and one other link can operate only in EMLSR mode.

[0245] In this respect, before the EMLSR mode is activated, the first MLD that sends the first PPDU may not send one or more frames / PPDUs on one or more links that operate only in EMLSR mode.

[0246] Additionally or alternatively, prior to activating EMLSR mode, the first MLD transmitting the first PPDU may use at least one of, but not all of, one or more links operating only in EMLSR mode to transmit one or more PPDUs / frames. For example, if Link 1 and Link 2 are links operating only in EMLSR mode, then only Link 1 may be used to transmit frames / PPDUs prior to activating EMLSR mode.

[0247] Additionally or alternatively, the first PPDU may include information about a link that can send one or more PPDUs / frames before activating EMLSR mode, in links operating only in EMLSR mode. This information may be indicated / provided in the form of an additional link bitmap. For example, bits for links that can send one or more PPDUs / frames may be set to the value '1' in the bitmap.

[0248] The second MLD can receive a first PPDU from the first MLD, which includes information about whether the link in operation can operate only in EMLSR mode.

[0249] In this regard, the second MLD that receives the first PPDU may not send one or more frames / PPDUs to the first MLD on one or more links that are only operating in EMLSR mode as indicated by the first MLD before activating EMLSR mode.

[0250] Additionally or alternatively, the second MLD that receives the first PPDU may use at least one, but not all, of the links that operate only in EMLSR mode as indicated by the first MLD to send one or more frames / PPDUs to the first MLD before activating EMLSR mode. For example, if links 1 and 2 of the first MLD are links that operate only in EMLSR mode, then only link 1 may be used to send frames / PPDUs to the first MLD before activating EMLSR mode.

[0251] Additionally or alternatively, the second MLD may receive information from the first PPDU received from the first MLD regarding a link that operates only in EMLSR mode, as indicated by the first MLD before activating EMLSR mode, and which may send one or more PPDUs / frames to the first MLD.

[0252] In the following text, reference will be made to Figure 19 and Figure 20 The operation of the STA according to the foregoing embodiments of this disclosure is described.

[0253] In other words, Figure 19 and Figure 20 The examples in this document may correspond to some of the various examples in this disclosure. For example, in Figure 19 and Figure 20 In this context, a STA belonging to the first MLD can be an STA that transmits ML elements including information about the link associated with the EMLSR mode, and a STA belonging to the second MLD can be an STA that receives ML elements. For example, a STA belonging to the first MLD can be a non-AP STA belonging to a non-AP MLD, and a STA belonging to the second MLD can be an AP belonging to an AP MLD.

[0254] Figure 19 An operational flowchart of a STA belonging to a first MLD according to an embodiment of the present disclosure is illustrated.

[0255] refer to Figure 19 A STA belonging to the first MLD can receive multilink elements related to the establishment of multiple links (e.g., a multilink establishment process) from a STA belonging to the second MLD (e.g., see [link]). Figure 10 (S1910).

[0256] For example, multilink elements can be sent via probe response frames, ML probe response frames, association response frames, reassociation response frames, etc. In other words, multilink elements can be included in response frames of request frames (e.g., probe request frames, ML probe request frames, association request frames, reassociation request frames, etc.) in which an STA belonging to a first MLD requests an STA belonging to a second MLD to perform multilink establishment.

[0257] In this regard, the multi-link element may include information about at least one of the multiple links that is associated with the EMLSR mode.

[0258] For example, information about at least one link associated with the EMLSR pattern can be included in a common information field within the multi-link element (see, for example, see...). Figure 10 and Figure 16 ).

[0259] Specifically, this information may include bitmap information (e.g., an EMLSR indication bitmap included in the public information field) indicating at least one of the multiple links that can operate only in EMLSR mode. In this regard, this information may be included in the Enhanced Multilink (EML) Capability subfield within the public information field.

[0260] For example, information about at least one link associated with the EMLSR pattern can be included in the link information field within the multi-link element.

[0261] Specifically, this information may include bitmap information (e.g., an EMLSR indicator bitmap included in the link information field), which indicates a link pair between the link indicated by the link information field and a link that can operate only in EMLSR mode. In this regard, the bitmap information may be included in the STA information field within the per STA profile sub-element of the configuration link information field (e.g., see...). Figure 10 and Figure 14 In addition, the STA control field within each STA profile sub-element may include a first sub-field indicating the existence of the corresponding link pair (e.g., Figure 14The EMLSR link pair shown has a subfield) or a second subfield indicating the size of the corresponding bitmap information (e.g., Figure 14 At least one of the EMLSR bitmap size subfields shown.

[0262] After completing the establishment process for multiple links as described above (e.g., multi-link establishment process), the STA belonging to the first MLD can receive control frames for initiating EMLSR mode (e.g., the initial control frame described above in this disclosure) from the STA belonging to the second MLD (S1920).

[0263] In this regard, the reception of control frames can be performed based on listening operations on at least one link associated with the EMLSR mode.

[0264] After the process based on the above control frame (e.g., receiving control frames and / or sending response frames to control frames), the STA belonging to the first MLD can perform frame exchange with the STA belonging to the second MLD based on EMLSR mode (S1930).

[0265] Regarding the above Figure 19 The process described herein, for at least one link associated with the EMLSR mode, allows the STA belonging to the first MLD to be configured to ignore information via the Non-Simultaneous Transmission and Reception (NSTR) indicator bitmap included in the multi-link element.

[0266] Additionally or alternatively, a multilink element may be defined to further include information indicating that the aforementioned multilink only supports EMLSR mode (e.g., Figure 18 The EMLSR only supports subfields shown.

[0267] Depend on Figure 19 The method described in the example, which belongs to the STA of the first MLD, can be executed by Figure 1 The first device (100) is executed. For example, Figure 1 One or more processors (102) of the first device (100) can be configured to receive multilink elements from STAs (200) belonging to the second MLD via one or more transceivers (106), receive control frames for initiating EMLSR mode from STAs (200) belonging to the second MLD, and perform frame exchange with STAs (200) belonging to the second MLD based on EMLSR mode. Furthermore, when executed by one or more processors (102), one or more memories (104) of the first device (100) can store information for execution. Figure 19 The example or instructions of the method described in the example above.

[0268] Figure 20An operational flowchart of a STA belonging to a second MLD according to an embodiment of the present disclosure is illustrated.

[0269] refer to Figure 20 A STA attached to a second MLD can send multilink elements related to the establishment of multiple links (e.g., a multilink establishment process) to a STA belonging to a first MLD (e.g., see [link]). Figure 10 (S2010).

[0270] In this regard, the multi-link element may include information about at least one link among multiple links that is associated with the EMLSR mode.

[0271] After the establishment process for multiple links is completed (e.g., multi-link establishment process), the STA belonging to the second MLD can send a control frame for initiating EMLSR mode (e.g., the initial control frame described above in this disclosure) to the STA belonging to the first MLD (S2020).

[0272] After the above-described control frame-based process (e.g., receiving a control frame and / or sending a response frame to the control frame), the STA belonging to the second MLD can perform frame exchange with the STA belonging to the first MLD based on EMLSR mode (S2030).

[0273] Details / examples regarding information included in multi-link elements for at least one link related to EMLSR mode, control frames used to initiate EMLSR mode, information related to supporting EMLSR mode, etc., are presented in [the relevant documentation / information]. Figure 19 The examples described are the same, and therefore redundant descriptions are omitted.

[0274] Depend on Figure 20 The method described in the example, which belongs to the STA execution of the second MLD, can be performed by... Figure 1 The second device (200) is executed. For example, Figure 1 One or more processors (202) of the second device (200) can be configured to send multilink elements to STAs (100) belonging to the first MLD via one or more transceivers (206), send control frames for initiating EMLSR mode to STAs (200) belonging to the first MLD, and perform frame exchange with STAs (200) belonging to the first MLD based on EMLSR mode. Furthermore, when executed by one or more processors (202), one or more memories (204) of the second device (200) can store information for execution. Figure 20 The example or the command of the method described in the example above.

[0275] In existing wireless LAN systems, only STR links or NSTR links are defined to be indicated during the multi-link establishment process. That is, information regarding links associated with EMLSR mode is not indicated during the multi-link establishment process, and is only indicated through subsequent processes (EML operation mode notification frame exchange). By default, EMLSR mode is disabled; therefore, how each link pair operates before being enabled is not defined. On the other hand, indicating information regarding links associated with EMLSR mode according to various examples of this disclosure during the multi-link establishment process achieves a novel effect of effectively utilizing EMLSR mode during the EMLSR mode enable / disable process.

[0276] The above embodiments combine the elements and features of this disclosure in a predetermined form. Unless otherwise expressly stated, each element or feature should be considered optional. Each element or feature may be implemented without being combined with other elements or features. Furthermore, embodiments of this disclosure may include combinations of some elements and / or features. The order of operations described in embodiments of this disclosure may be changed. Some elements or features of one embodiment may be included in other embodiments, or may be replaced by corresponding elements or features of other embodiments. Obviously, embodiments may include claims that are not explicitly referenced in the claims, or may be included as new claims after the application has been amended.

[0277] It will be apparent to those skilled in the art that this disclosure may be implemented in other specific forms without departing from its essential characteristics. Therefore, the above detailed description should not be construed as restrictive in every respect, but rather as illustrative. The scope of this disclosure should be determined by a reasonable interpretation of the appended claims, and all variations within the equivalent scope of this disclosure are included within its scope.

[0278] The scope of this disclosure includes software or machine-executable commands (e.g., operating systems, applications, firmware, programs, etc.) that operate in a device or computer according to methods of various embodiments, as well as non-transitory computer-readable media that cause software or commands to be stored and executable in a device or computer. Commands that can be used to program a processing system to perform the features described in this disclosure can be stored in a storage medium or a computer-readable storage medium, and the features described in this disclosure can be implemented by using a computer program product including such a storage medium. The storage medium may include, but is not limited to, high-speed random access memory, such as DRAM, SRAM, DDR RAM, or other random access solid-state storage devices, and may include non-volatile memory, such as one or more disk storage devices, optical disk storage devices, flash memory devices, or other non-volatile solid-state storage devices. The memory may optionally include one or more storage devices located remotely from the processor. The memory, or alternatively, the non-volatile memory devices in the memory include non-transitory computer-readable storage media. The features described in this disclosure can be stored in any machine-readable medium to control the hardware of a processing system and can be integrated into software and / or firmware that allows the processing system to interact with other mechanisms using the results of embodiments of this disclosure. Such software or firmware may include, but is not limited to, application code, device drivers, operating systems, and execution environments / containers.

[0279] Industrial applicability

[0280] The method presented in this disclosure is primarily described based on examples applied to IEEE 802.11-based systems (5G systems), but can be applied to various WLAN or wireless communication systems other than IEEE 802.11-based systems.

Claims

1. A method performed by a station (STA) belonging to a first multilink device (MLD) in a wireless LAN system, the method comprising: The STA belonging to the second MLD receives multi-link elements related to the establishment of multiple links; Receive control frames from the STA belonging to the second MLD for initiating the Enhanced Multilink Single Radio EMLSR mode; as well as Based on the EMLSR mode, the STA execution frame is exchanged with the second MLD. The multi-link element includes information about at least one link among the plurality of links that is related to the EMLSR mode.

2. The method according to claim 1, wherein, The reception of the control frame is performed based on the listening operation of the at least one link.

3. The method according to claim 1, wherein, Information for the at least one link is included in the common information field of the multi-link element.

4. The method according to claim 3, wherein, The information for the at least one link includes bitmap information indicating at least one of the plurality of links that can only operate in the EMLSR mode.

5. The method according to claim 3, wherein, The information for the at least one link is included in the Enhanced Multi-Link EML Capability subfield of the Public Information field.

6. The method according to claim 1, wherein, The information for the at least one link is included in the link information field of the multi-link element.

7. The method according to claim 6, wherein, The information for the at least one link includes bitmap information indicating a link pair between the link indicated by the link information field and a link that can only operate in the EMLSR mode.

8. The method according to claim 7, wherein, The bitmap information is included in the STA information field of each STA profile sub-element that configures the link information field.

9. The method according to claim 8, wherein, The STA control field in each STA profile sub-element includes at least one of a first sub-field indicating whether the link pair exists or a second sub-field indicating the size of the bitmap information.

10. The method according to claim 1, wherein, For the at least one link associated with the EMLSR mode The STA belonging to the first MLD is configured to ignore information by sending and receiving NSTR indication bitmaps not simultaneously in the multi-link element.

11. The method according to claim 1, wherein, The multi-link element is defined to also include information indicating that the multiple links only support the EMLSR mode.

12. An apparatus for a station STA belonging to a first multi-link device (MLD) in a wireless local area network (WLAN) system, the apparatus comprising: At least one transceiver; as well as At least one processor, said at least one processor being connected to said at least one transceiver, Wherein, the at least one processor is configured to: The STA belonging to the second MLD receives multi-link elements related to the establishment of multiple links; The STA belonging to the second MLD receives a control frame for initiating an enhanced multilink single radio EMLSR mode; and Based on the EMLSR mode, the STA execution frame is exchanged with the second MLD. The multi-link element includes information about at least one link among the plurality of links that is related to the EMLSR mode.

13. A method performed by a station STA belonging to a second multilink device (MLD) in a wireless local area network (LAN) system, the method comprising: Send multi-link elements related to the establishment of multiple links to the STA belonging to the first MLD; Send a control frame to the STA belonging to the first MLD to initiate the Enhanced Multilink Single Radio EMLSR mode; as well as Based on the EMLSR mode, the STA execution frame is exchanged with the first MLD. The multi-link element includes information about at least one link among the plurality of links that is related to the EMLSR mode.

14. An apparatus for a station STA belonging to a second multi-link device (MLD) in a wireless local area network (WLAN) system, the apparatus comprising: At least one transceiver; as well as At least one processor, said at least one processor being connected to said at least one transceiver, Wherein, the at least one processor is configured to: Send multi-link elements related to the establishment of multiple links to the STA belonging to the first MLD; Send a control frame to the STA belonging to the first MLD to initiate the Enhanced Multilink Single Radio EMLSR mode; and Based on the EMLSR mode, the STA execution frame is exchanged with the first MLD. The multi-link element includes information about at least one link among the plurality of links that is related to the EMLSR mode.

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

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

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