Method and apparatus for transmitting and receiving inheritance-based information in a wireless LAN system

Abstract

A method and apparatus for transmitting and receiving inheritance-based information in a wireless LAN system are disclosed. A method performed by a station (STA) in a wireless LAN system according to an embodiment of the present disclosure includes transmitting a request frame including information related to one or more of a second access point (AP) or a first multi-link device (MLD) to a first AP, and receiving a response frame for the request frame from the first AP, wherein the response frame includes a profile for each of one or more STAs, and inheritance or non-inheritance for the profile for each of the one or more STAs may be based on a profile of a non-transmitted (non-Tx) basic service set identifier (BSSID).

Description

Technical Field

[0001] The present disclosure relates to a method and apparatus for transmitting and receiving inheritance-based information in a Wireless Local Area Network (WLAN) system.

Background Art

[0002] New technologies for improving the transmission rate, increasing the bandwidth, improving the reliability, reducing the errors, and reducing the latency of Wireless Local Area Network (WLAN) have been introduced. Among the WLAN technologies, the standards of the Institute of Electrical and Electronics Engineers (IEEE) 802.11 series can be referred to as Wi-Fi. For example, the technologies recently introduced to the WLAN include enhancements for Very High-Throughput (VHT) of the 802.11ac standard, enhancements for High Efficiency (HE) of the IEEE 802.11ax standard, etc.

[0003] To provide a more improved wireless communication environment, improvement technologies for Extremely High Throughput (EHT) are being discussed. For example, technologies for increasing the bandwidth, efficiently utilizing multiple bands, Multiple Input Multiple Output (MIMO) that supports an increased number of spatial streams, and technologies for multi-access point (AP) coordination are being studied. In particular, various technologies for supporting traffic with low latency or real-time characteristics are being studied. In addition, new technologies for supporting ultra high reliability (UHR), including the improvement or extension of EHT technologies, are being discussed.

Summary of the Invention

Problems to be Solved by the Invention

[0004] The technical problem of the present disclosure is to provide a method and an apparatus for transmitting or receiving inheritance-based information in a wireless LAN system.

[0005] A further technical problem of the present disclosure is to provide a method and an apparatus for determining a reference for inheritance based on an MLD (multi-link device) and a multiple BSSID (multiple basic service set identifier (multi-BSSID)) in a wireless LAN system.

[0006] The technical problem to be achieved in the present disclosure is not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly understood by those having ordinary knowledge in the technical field to which the present disclosure pertains from the following description.

Means for Solving the Problem

[0007] A method performed by a station (STA) in a wireless LAN system according to an aspect of the present disclosure includes transmitting a request frame including information related to one or more of a second access point (AP) or a first multi-link device (MLD) to a first access point (AP), and receiving a response frame for the request frame from the first AP, wherein the response frame includes a per-STA profile for each of one or more STAs, and inheritance or non-inheritance for the per-STA profile for each of the one or more STAs may be based on a profile of a non-transmitted (non-Tx) basic service set identifier (BSSID).

[0008] In a wireless LAN system according to a further aspect of the present disclosure, a method performed by a first access point (AP) includes receiving a request frame including information related to one or more of a second access point (AP) or a first multi-link device (MLD) from a station (STA), and transmitting a response frame to the STA in response to the request frame, wherein the response frame includes a profile for each of one or more STAs, and inheritance or non-inheritance for the profile for each of the one or more STAs may be based on a profile of a non-transmitted (non-Tx) basic service set identifier (BSSID).

Advantages of the Invention

[0009] According to the present disclosure, a method and an apparatus for transmitting or receiving inheritance-based information in a wireless LAN system can be provided.

[0010] According to the present disclosure, a method and an apparatus for determining a reference for inheritance based on an MLD (multi-link device) and a multiple BSSID (multiple basic service set identifier) in a wireless LAN system can be provided.

[0011] The effects obtained from the present disclosure are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those of ordinary skill in the technical field to which the present disclosure pertains from the following description.

Brief Description of the Drawings

[0012] The accompanying drawings, which are included as a part of the detailed description to assist in understanding the present disclosure, provide examples of embodiments of the present disclosure and, together with the detailed description, explain the technical features of the present disclosure.

[0013]

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Embodiments for Carrying Out the Invention

[0014] Hereinafter, preferred embodiments according to the present disclosure will be described in detail with reference to the accompanying drawings. The detailed description disclosed below together with the accompanying drawings is for explaining exemplary embodiments of the present disclosure and is not for showing the only embodiments in which the present disclosure can be implemented. The following detailed description includes specific details in order to provide a complete understanding of the present disclosure. However, it is understood by those skilled in the art that the present disclosure can be implemented without such specific details.

[0015] In some cases, to avoid ambiguity of the concept of the present disclosure, known structures and devices may be omitted and may be shown in the form of a block diagram centered on the core functions of each structure and device.

[0016] In the present disclosure, when a certain component is "connected", "coupled" or "connected" to another component, this may include not only a direct connection relationship but also an indirect connection relationship in which there are further other components between them. Also, in the present disclosure, the terms "comprising" or "having" identify the presence of the recited features, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, elements, components and / or groups thereof.

[0017] In the present disclosure, terms such as "first", "second", etc. are only used for the purpose of distinguishing one component from another and are not used to limit the components. Unless otherwise specifically mentioned, they do not limit the order or importance among the components. Therefore, within the scope of the present disclosure, the first component in one embodiment can also be referred to as the second component in another embodiment, and similarly, the second component in one embodiment can also be referred to as the first component in another embodiment.

[0018] The terms used in this disclosure are for the purpose of describing particular embodiments and are not intended to limit the scope of the claims. As used in the description of the embodiments and the appended claims, the singular forms are also intended to include the plural forms unless the context clearly dictates otherwise. The term "and / or" as used in this disclosure may refer to one of the related listed items or may include any and all possible combinations of two or more of them. Also, in this disclosure, " / " between words has the same meaning as "and / or" unless otherwise specified.

[0019] The examples of this disclosure may be applied to various wireless communication systems. For example, the examples of this disclosure may be applied to a wireless LAN system. For example, the examples of this disclosure may be applied to an IEEE 802.11a / g / n / ac / ax standard-based wireless LAN. Note that the examples of this disclosure may be applied to a newly proposed IEEE 802.11bn (or, UHR) standard-based wireless LAN. Furthermore, the examples of this disclosure may also be applied to a next-generation standard-based wireless LAN after IEEE 802.11bn. Also, the examples of this disclosure may be applied to a cellular wireless communication system. For example, it may be applied to a cellular wireless communication system based on the technologies of the LTE (Long Term Evolution) series and the 5G NR (New Radio) series of the 3GPP (registered trademark) (3rd Generation Partnership Project) standard.

[0020] Hereinafter, the technical features to which the examples of this disclosure can be applied will be described.

[0021] FIG. 1 is a block configuration diagram illustrating a wireless communication device according to an embodiment of this disclosure.

[0022] The first device 100 and the second device 200 illustrated in FIG. 1 may be referred to by various terms such as a terminal, a wireless device, a Wireless Transmit Receive Unit (WTRU), a User Equipment (UE), a Mobile Station (MS), a user terminal (UT), a Mobile Subscriber Station (MSS), a Mobile Subscriber Unit (MSS), a Subscriber Station (SS), an Advanced Mobile Station (AMS), a Wireless terminal (WT), or simply a user. Also, the first device 100 and the second device 200 may be referred to by various terms such as an Access Point (AP), a Base Station (BS), a fixed station, a Node B, a Base Transceiver System (BTS), a network, an Artificial Intelligence (AI) system, a Road Side Unit (RSU), a repeater, a router, a relay, a gateway, etc.

[0023] The devices 100 and 200 illustrated in FIG. 1 may also be referred to as a station (STA). For example, the devices 100 and 200 illustrated in FIG. 1 may be referred to by various terms such as a transmitting device, a receiving device, a transmitting STA, a receiving STA, etc. For example, STAs 110 and 200 may play the role of an AP (access point) or a non-AP. That is, in the present disclosure, STAs 110 and 200 may have the functions of an AP and / or a non-AP. When STAs 110 and 200 have the AP function, they may simply be referred to as an AP, and when STAs 110 and 200 have the non-AP function, they may simply be referred to as an STA. Also, in the present disclosure, an AP may be denoted as an AP STA.

[0024] Referring to FIG. 1, the first device 100 and the second device 200 can transmit and receive wireless signals using various wireless LAN technologies (e.g., IEEE 802.11 series). The first device 100 and the second device 200 may include interfaces for a medium access control (MAC) layer and a physical layer (PHY) that comply with the provisions of the IEEE 802.11 standard.

[0025] In addition, the first device 100 and the second device 200 can further support various communication standards other than wireless LAN technologies (e.g., 3GPP LTE series, 5G NR series standards, etc.). Also, the devices of the present disclosure may be embodied by various devices such as mobile phones, vehicles, personal computers, AR (Augmented Reality) equipment, VR (Virtual Reality) equipment, etc. Further, the STAs in this specification can support various communication services such as voice calls, video calls, data communication, autonomous driving, MTC (Machine-Type Communication), M2M (Machine-to-Machine), D2D (Device-to-Device), IoT (Internet-of-Things), etc.

[0026] The first device 100 includes one or more processors 102 and one or more memories 104, and may further include one or more transceivers 106 and / or one or more antennas 108. The processor 102 controls the memory 104 and / or the transceiver 106 and may be configured to implement the descriptions, functions, procedures, proposals, methods, and / or operation flowcharts in the present disclosure. For example, after processing the information in the memory 104 to generate a first piece of information / signal, the processor 102 can transmit a wireless signal including the first piece of information / signal via the transceiver 106. Also, after receiving a wireless signal including a second piece of information / signal via the transceiver 106, the processor 102 can store the information obtained from the signal processing of the second piece of information / signal in the memory 104. The memory 104 may be connected to the processor 102 and can store various information related to the operation of the processor 102. For example, the memory 104 can store software code including instructions to execute part or all of the processes controlled by the processor 102 or to execute the descriptions, functions, procedures, proposals, methods, and / or operation sequence diagrams in the present disclosure. Here, the processor 102 and the memory 104 may be part of a communication modem / circuit / chip designed to implement wireless LAN technology (e.g., the IEEE 802.11 series). The transceiver 106 may be connected to the processor 102 and can transmit and / or receive wireless signals via one or more antennas 108. The transceiver 106 may include a transmitter and / or a receiver. The transceiver 106 may be used in the same sense as an RF (Radio Frequency) unit. In the present disclosure, the device can also mean a communication modem / circuit / chip.

[0027] The second device 200 includes one or more processors 202 and one or more memories 204, and may further include one or more transceivers 206 and / or one or more antennas 208. The processor 202 controls the memory 204 and / or the transceiver 206 and may be configured to implement the descriptions, functions, procedures, proposals, methods, and / or operation sequence diagrams disclosed in the present disclosure. For example, after processing the information in the memory 204 to generate a third piece of information / signal, the processor 202 can transmit a wireless signal including the third piece of information / signal via the transceiver 206. Also, after receiving a wireless signal including a fourth piece of information / signal via the transceiver 206, the processor 202 can store the information obtained from the signal processing of the fourth piece of information / signal in the memory 204. The memory 204 may be connected to the processor 202 and can store various information related to the operation of the processor 202. For example, the memory 204 can store software code including instructions for executing part or all of the processes controlled by the processor 202 or for implementing the descriptions, functions, procedures, proposals, methods, and / or operation sequence diagrams disclosed in the present disclosure. Here, the processor 202 and the memory 204 may be part of a communication modem / circuit / chip designed to implement wireless LAN technology (e.g., the IEEE 802.11 series). The transceiver 206 may be connected to the processor 202 and can transmit and / or receive wireless signals via one or more antennas 208. The transceiver 206 may include a transmitter and / or a receiver. The transceiver 206 may be used in the same sense as an RF unit. In the present disclosure, the device may also mean a communication modem / circuit / chip.

[0028] Hereinafter, the hardware elements of devices 100 and 200 will be described in more detail. Although not limited thereto, one or more protocol layers may be implemented by one or more processors 102 and 202. For example, one or more processors 102 and 202 can implement one or more layers (for example, functional layers such as PHY and MAC). One or more processors 102 and 202 can generate one or more PDUs (Protocol Data Units) and / or one or more SDUs (Service Data Units) according to the descriptions, functions, procedures, proposals, methods, and / or operation sequence diagrams in the present disclosure. One or more processors 102 and 202 can generate messages, control information, data, or information according to the descriptions, functions, procedures, proposals, methods, and / or operation sequence diagrams in the present disclosure. One or more processors 102 and 202 can generate a signal (for example, a baseband signal) including a PDU, an SDU, a message, control information, data, or information according to the functions, procedures, proposals, and / or methods in the present disclosure and provide it to one or more transceivers 106 and 206. One or more processors 102 and 202 can receive a signal (for example, a baseband signal) from one or more transceivers 106 and 206 and obtain a PDU, an SDU, a message, control information, data, or information according to the descriptions, functions, procedures, proposals, methods, and / or operation sequence diagrams in the present disclosure.

[0029] One or more processors 102, 202 can be referred to as a controller, microcontroller, microprocessor, or microcomputer. The one or more processors 102, 202 may be embodied by hardware, firmware, software, or a combination thereof. As an 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 the one or more processors 102, 202. The descriptions, functions, procedures, proposals, methods, and / or operation sequence diagrams disclosed in the present disclosure may be embodied using firmware or software, and the firmware or software may be embodied to include modules, procedures, functions, etc. The firmware or software configured to execute the descriptions, functions, procedures, proposals, methods, and / or operation sequence diagrams disclosed in the present disclosure may be included in the one or more processors 102, 202, stored in the one or more memories 104, 204, and driven by the one or more processors 102, 202. The descriptions, functions, procedures, proposals, methods, and / or operation sequence diagrams disclosed in the present disclosure may be embodied by firmware or software in the form of code, instruction words, and / or a set of instruction words.

[0030] One or more memories 104, 204 may be coupled to one or more processors 102, 202 and can store various forms of data, signals, messages, information, programs, code, instructions and / or commands. The one or more memories 104, 204 may be constituted by a ROM, a RAM, an EPROM, a flash memory, a hard drive, a register, a cache memory, a computer-readable storage medium and / or a combination thereof. The one or more memories 104, 204 may be located inside and / or outside the one or more processors 102, 202. Also, the one or more memories 104, 204 may be coupled to the one or more processors 102, 202 by various techniques such as wired or wireless connections.

[0031] One or more transceivers 106, 206 can transmit user data, control information, radio signals / channels, etc. mentioned in the methods and / or operation sequence diagrams of the present disclosure to one or more other devices. One or more transceivers 106, 206 can receive user data, control information, radio signals / channels, etc. mentioned in the descriptions, functions, procedures, proposals, methods, and / or operation sequence diagrams disclosed in the present disclosure from one or more other devices. For example, one or more transceivers 106, 206 may be connected to one or more processors 102, 202 and can transmit and receive radio signals. For example, one or more processors 102, 202 can control one or more transceivers 106, 206 to transmit user data, control information, or radio signals to one or more other devices. Also, one or more processors 102, 202 can control one or more transceivers 106, 206 to receive user data, control information, or radio signals from one or more other devices. Also, 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, radio signals / channels, etc. mentioned in the descriptions, functions, procedures, proposals, methods, and / or operation sequence diagrams disclosed in the present disclosure via one or more antennas 108, 208. In the present disclosure, one or more antennas may be multiple physical antennas or multiple logical antennas (e.g., antenna ports). One or more transceivers 106, 206 may convert received radio signals / channels, etc. from RF band signals to baseband signals in order to process received user data, control information, radio signals / channels, etc. using one or more processors 102, 202. One or more transceivers 106, 206 may convert user data, control information, radio signals / channels, etc. processed using one or more processors 102, 202 from baseband signals to RF band signals. For this purpose, one or more transceivers 106, 206 may include (analog) oscillators and / or filters.

[0032] For example, either one of STA100 and 200 can perform the intended operation of the AP, and the other one of STA100 and 200 can perform the intended operation of a non-AP STA. For example, the transceivers 106 and 206 in FIG. 1 can perform the transmission and reception operations of signals (e.g., packets or PPDUs (Physical layer Protocol Data Units) conforming to IEEE 802.11a / b / g / n / ac / ax / be / bn, etc.). Also, in the present disclosure, operations in which various STAs generate transmission and reception signals or perform data processing and calculations in advance for the transmission and reception signals may be performed by the processors 102 and 202 in FIG. 1. For example, an example of an operation of generating a transmission and reception signal or performing data processing and calculations in advance for the transmission and reception signal includes: 1) an operation of determining / acquiring / configuring / calculating / decoding / encoding bit information of fields (such as SIG (signal), STF (short training field), LTF (long training field), Data, etc.) included in the PPDU; 2) an operation of determining / configuring / acquiring time resources and frequency resources (e.g., subcarrier resources) used for fields (such as SIG, STF, LTF, Data, etc.) included in the PPDU; 3) an operation of determining / configuring / acquiring a specific sequence (e.g., pilot sequence, STF / LTF sequence, extra sequence applied to SIG) used for fields (such as SIG, STF, LTF, Data, etc.) included in the PPDU; 4) a power control operation and / or a power saving operation applied to the STA; 5) operations related to determining / acquiring / configuring / calculating / decoding / encoding an ACK signal, etc. Also, in the following example, various information (e.g., information regarding fields / sub-fields / control fields / parameters / power, etc.) used by various STAs for determining / acquiring / configuring / calculating / decoding / encoding transmission and reception signals may be stored in the memories 104 and 204 in FIG. 1.

[0033] Hereinafter, the downlink (DL) means a link for communication from the AP STA to the non-AP STA, and downlink PPDUs / packets / signals, etc. may be transmitted and received through the downlink. In downlink communication, the transmitter may be part of the AP STA and the receiver may be part of the non-AP STA. The uplink (UL) means a link for communication from the non-AP STA to the AP STA, and uplink PPDUs / packets / signals, etc. may be transmitted and received through the uplink. In uplink communication, the transmitter may be part of the non-AP STA and the receiver may be part of the AP STA.

[0034] FIG. 2 is a diagram showing an exemplary structure of a wireless LAN system to which the present disclosure is applicable.

[0035] The structure of the wireless LAN system may be composed of a plurality of components. A wireless LAN that supports STA mobility transparent to the upper layer may be provided by the interaction of the plurality of components. A BSS (Basic Service Set) corresponds to the basic building block of the wireless LAN. In FIG. 2, an example is shown in which two BSSs (BSS1 and BSS2) exist and two STAs are included as members of each BSS (STA1 and STA2 are included in BSS1, and STA3 and STA4 are included in BSS2). In FIG. 2, the ellipse representing the BSS may be understood to represent the coverage area in which the STAs included in the BSS maintain communication. This area can be referred to as the BSA (Basic Service Area). When a STA moves outside the BSA, it can no longer communicate directly with other STAs within the BSA.

[0036] If the DS shown in FIG. 2 is not considered, the most basic type of BSS in a wireless LAN is an Independent BSS (IBSS). For example, an IBSS can have the smallest form composed of only two STAs. For example, assuming that other components are omitted, BSS1 composed of only STA1 and STA2, or BSS2 composed of only STA3 and STA4 can each correspond to a typical example of an IBSS. Such a configuration is possible when an STA can communicate directly without an AP. Also, such a form of wireless LAN is not pre-planned and configured, but can be configured when a LAN is needed, and this can also be referred to as an ad-hoc network. Since an IBSS does not include an AP, there is no centralized management entity that performs management functions centrally. That is, in an IBSS, STAs are managed in a distributed manner. In an IBSS, all STAs may be composed of mobile STAs, connection to a distributed system (DS) is not allowed, and it forms a self-contained network.

[0037] The membership of STAs in a BSS may be dynamically changed due to an STA joining or leaving, or an STA entering or leaving the BSS area. In order to become a member of a BSS, an STA can join the BSS using a synchronization process. In order to access all services of the BSS-based structure, an STA needs to be associated with the BSS. Such an association may be set dynamically and may include the use of a Distribution System Service (DSS).

[0038] In a wireless LAN, the direct STA-to-STA distance may be limited by PHY performance. In some cases, such distance limitations may be sufficient, but in some cases, communication between STAs at a greater distance may be required. A distributed system (DS) may be configured to support extended coverage.

[0039] DS means a structure in which BSSs are interconnected. Specifically, as shown in FIG. 2, a BSS may exist as a component of an extended form of a network composed of a plurality of BSSs. DS is a logical concept and may be specified by the characteristics of a distributed system medium (DSM). In this regard, a wireless medium (Wireless Medium, WM) and DSM may be logically separated. Each logical medium is used for different purposes and is used by different components. These media are not limited to being the same or different. The flexibility of the wireless LAN structure (DS structure or other network structures) can be explained by the fact that a plurality of media are logically different from each other. That is, the wireless LAN structure may be implemented in various ways, and the wireless LAN structure may be specified independently according to the physical characteristics of each implementation example.

[0040] DS can support mobile devices by providing seamless integration of a plurality of BSSs and providing the logical services necessary for handling addresses to destinations. Further, DS may further include a component called a portal that acts as a bridge for connecting a wireless LAN and other networks (e.g., IEEE 802.X).

[0041] AP means an entity that enables access to the DS through the WM for an associated non-AP STA and also has the functionality of the STA. Data movement between the BSS and the DS can be performed via the AP. For example, STA2 and STA3 shown in FIG. 2 provide the function of enabling the associated non-AP STAs (STA1 and STA4) to access the DS while having the functionality of the STA. Also, since all APs basically correspond to STAs, all APs are addressable entities. The address used by the AP for communication on the WM does not necessarily have to be the same as the address used by the AP for communication on the DSM. A BSS composed of an AP and one or more STAs can be referred to as an infrastructure BSS.

[0042] Data transmitted from one of the STAs associated with an AP to the STA address of the AP is always received at the uncontrolled port and may be processed by the IEEE 802.1X port access entity. Also, when the controlled port is authenticated, the transmitted data (or frame) can be transmitted to the DS.

[0043] An Extended Service Set (ESS) for providing a wider coverage may be set in the structure of the DS described above.

[0044] An ESS means a network composed of a DS and BSSs, having an arbitrary size and complexity. An ESS may correspond to a set of BSSs connected to one DS. However, an ESS does not include a DS. The ESS network is characterized in that it appears as an IBSS at the LLC (Logical Link Control) layer. STAs included in an ESS can communicate with each other, and a mobile STA can transparently move from one BSS to another (within the same ESS) to the LLC. APs included in one ESS may have the same SSID (service set identification). The SSID is distinguished from the BSSID which is the identifier of the BSS.

[0045] In a wireless LAN system, without making any assumptions about the relative physical positions of BSSs, any of the following forms are possible. BSSs may partially overlap, which is a commonly used form to provide continuous coverage. Also, BSSs do not have to be physically connected, and logically there is no limit to the distance between BSSs. Also, BSSs may be physically located at the same position, which may be used to provide redundancy. Also, one (or one or more) IBSS or ESS networks may physically exist in the same space as one (or one or more) ESS networks. This may correspond to the ESS network form when an ad hoc network operates at the location where an ESS network exists, when wireless networks physically overlapping are configured by different organizations, or when two or more different access and security policies are required at the same location.

[0046] Figure 3 is a diagram for explaining a link setup process to which the present disclosure is applicable.

[0047] In order for a STA to set up a link with a network and transmit and receive data, it must first discover the network, perform authentication, establish an association, and carry out authentication procedures for security. The link setup process can be referred to as the session start process or the session setup process. Also, the processes of discovery, authentication, association, and security setup in the link setup process can be collectively referred to as the association process.

[0048] In step S310, the STA can perform a network discovery operation. The network discovery operation may include the scanning operation of the STA. That is, in order for the STA to access the network, it must search for networks that it can participate in. The STA must identify compatible networks before participating in a wireless network, and the process of identifying networks existing in a specific area is called scanning.

[0049] Scanning methods include active scanning and passive scanning. In FIG. 3, an example of a network discovery operation including an active scanning process is shown. In active scanning, the STA performing the scanning sends a probe request frame (probe request frame) to search for what APs exist in the vicinity while moving channels, and waits for a response thereto. The responder sends a probe response frame as a response to the probe request frame to the STA that 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. Since the AP sends a beacon frame in the BSS, the AP becomes the responder. In an IBSS, since STAs within the IBSS send beacon frames alternately, the responder is not constant. For example, a STA that sends a probe request frame on channel 1 and receives a probe response frame on channel 1 saves the BSS-related information included in the received probe response frame, moves to the next channel (e.g., channel 2), and can perform scanning in the same way (i.e., send and receive probe requests / responses on channel 2).

[0050] Although not shown in FIG. 3, the scanning operation may be performed in a passive scanning mode. In passive scanning, the STA that performs scanning waits for beacon frames while moving channels. A beacon frame is one of the management frames defined in IEEE 802.11, which notifies the existence of a wireless network and is periodically transmitted so that a STA performing scanning can search for a wireless network and participate in the wireless network. In a BSS, the AP plays the role of periodically transmitting beacon frames, and in an IBSS, the STAs within the IBSS transmit beacon frames alternately. When a STA performing scanning receives a beacon frame, it stores the information about the BSS contained in the beacon frame and records the beacon frame information on each channel while moving to other channels. The STA that has received a beacon frame can store the BSS-related information contained in the received beacon frame and move to the next channel to perform scanning on the next channel in the same way. Comparing active scanning and passive scanning, active scanning has the advantage that the delay and power consumption are smaller than those of passive scanning.

[0051] After the STA discovers the network, an authentication process may be performed in step S320. Such an authentication process can be called the first authentication process in order to clearly distinguish it from the security setup operation in step S340 described later.

[0052] The authentication process includes a process in which the STA transmits an authentication request frame (authentication request frame) to the AP and, in response, the AP transmits an authentication response frame to the STA. The authentication frame used for authentication request / response corresponds to a management frame.

[0053] The authentication frame may include information regarding an authentication algorithm number, an authentication transaction sequence number, a status code, a challenge text, a Robust Security Network (RSN), a Finite Cyclic Group, etc. This corresponds to an exemplification of some of the information that may be included in an authentication request / response frame, and may be replaced by other information or further additional information may be included.

[0054] The STA can send an authentication request frame to the AP. The AP can determine whether to allow authentication for the STA based on the information included in the received authentication request frame. The AP can provide the result of the authentication process to the STA using an authentication response frame.

[0055] After the STA is successfully authenticated, an association process may be performed at step S330. The association process includes a process in which the STA sends an association request frame to the AP, and in response, the AP sends an association response frame to the STA.

[0056] For example, the association request frame may include information regarding various capabilities, beacon listen interval, SSID (service set identifier), supported rates, supported channels, RSN, mobility domain, supported operating classes, TIM (Traffic Indication Map) broadcast request, information regarding interworking service capabilities, and the like. For example, the association response frame may include information regarding various capabilities, status code, AID (Association ID), supported rates, EDCA (Enhanced Distributed Channel Access) parameter set, RCPI (Received Channel Power Indicator), RSNI (Received Signal to Noise Indicator), mobility domain, timeout interval (e.g., association comeback time), overlapping BSS scan parameters, TIM broadcast response, QoS (Quality of Service) map, and the like. This corresponds to an example of some of the information that may be included in the association request / response frame, and may be replaced by other information or may further include additional information.

[0057] After the STA is successfully associated with the network, the security setup process may be performed in step S340. The security setup process in step S340 can also be said to be an authentication process using RSNA (Robust Security Network Association) requests / responses. The authentication process in step S320 is referred to as the first authentication process, and the security setup process in step S340 can also be simply referred to as the authentication process.

[0058] The security setup process in step S340 may include, for example, a process of setting up a private key using a 4-way handshaking using EAPOL (Extensible Authentication Protocol over LAN) frames. Also, the security setup process may be performed by a security method not defined by the IEEE 802.11 standard.

[0059] FIG. 4 is a diagram for explaining a backoff process to which the present disclosure is applicable.

[0060] In a wireless LAN system, the basic access mechanism of MAC (Medium Access Control) is the CSMA / CA (Carrier Sense Multiple Access with Collision Avoidance) mechanism. The CSMA / CA mechanism, also called the Distributed Coordination Function (DCF) of IEEE 802.11 MAC, basically adopts a "listen before talk" access mechanism. According to such a type of access mechanism, the AP and / or STA can perform a Clear Channel Assessment (CCA) to sense the wireless channel or medium (for example, DIFS (DCF Inter-Frame Space)) for a predetermined time interval before starting transmission. As a result of the sensing, if it is determined that the medium is in an idle status, frame transmission is started through the medium. On the other hand, if the medium is sensed as being in an occupied or busy state, the AP and / or STA do not start their own transmission and can set a delay period for medium access (for example, a random backoff period) and wait, and then attempt frame transmission. By applying the random backoff period, it is expected that multiple STAs will attempt frame transmission after waiting for different times from each other, so collisions can be minimized.

[0061] In addition, the IEEE 802.11 MAC protocol provides HCF (Hybrid Coordination Function). HCF is based on the above-mentioned DCF and PCF (Point Coordination Function). PCF refers to a polling-based synchronous access method, which means a method of periodically polling so that all receiving APs and / or STAs can receive data frames. In addition, HCF has EDCA (Enhanced Distributed Channel Access) and HCCA (HCF Controlled Channel Access). EDCA is an access method in which the provider makes the access method for providing data frames to multiple users be competition-based, and HCCA is to use a non-competition-based channel access method using a polling mechanism. In addition, HCF includes a medium access mechanism for improving the QoS (Quality of Service) of a wireless LAN, and QoS data can be transmitted in both the Contention Period (CP) and the Contention Free Period (CFP).

[0062] With reference to FIG. 4, the operation based on the random backoff period will be described. When the medium that was in the occupied / busy state changes to the idle state, a plurality of STAs can attempt to transmit data (or frames). As a measure to minimize collisions, each STA can select a random backoff count and attempt transmission after waiting for the corresponding slot time. The random backoff count has a pseudo-random integer value and can be determined to be any one of the values in the range of 0 to CW. Here, CW is the contention window parameter value. The CW parameter is given an initial value of CWmin, but can take on a value twice as large in the case of a transmission failure (for example, when an ACK for the transmitted frame cannot be received). When the CW parameter value reaches CWmax, data transmission can be attempted while maintaining the CWmax value until successful data transmission, and is reset to the CWmin value when successful data transmission occurs. The CW, CWmin, and CWmax values are preferably set to 2 n -1 (n = 0, 1, 2,...).

[0063] When the random backoff process starts, the STA continues to monitor the medium while counting down the backoff slots by the determined backoff count value. When the medium is monitored as being in the occupied state, the countdown stops and waits, and when the medium becomes idle, the remaining countdown resumes.

[0064] In the illustration of FIG. 4, when a packet to be transmitted arrives at the MAC of STA3, STA3 can confirm that the medium has been idle for only the DIFS and immediately transmit the frame. The remaining STAs monitor that the medium is in the occupied / busy state and wait. During this time, data to be transmitted may occur in each of STA1, STA2, and STA5. When each STA monitors that the medium is in the idle state, after waiting for only the DIFS, it can count down the backoff slots according to the random backoff count value it has selected. Assume that STA2 selects the minimum backoff count value and STA1 selects the maximum backoff count value. That is, an example is illustrated in which when STA2 finishes the backoff count and starts frame transmission, the remaining backoff time of STA5 is shorter than the remaining backoff time of STA1. STA1 and STA5 stop counting down for a while and wait while STA2 occupies the medium. When STA2's occupation ends and the medium becomes idle again, STA1 and STA5 wait for only the DIFS and then resume the stopped backoff count. That is, after counting down the remaining backoff slots for only the remaining backoff time, frame transmission can be started. Since the remaining backoff time of STA5 is shorter than that of STA1, STA5 starts frame transmission. Data to be transmitted may also occur at STA4 while STA2 occupies the medium. From the perspective of STA4, when the medium becomes idle, after waiting for only the DIFS, it can count down according to the random backoff count value it has selected and start frame transmission. The illustration of FIG. 4 shows a case where the remaining backoff time of STA5 accidentally coincides with the random backoff count value of STA4. In this case, a collision may occur between STA4 and STA5. If a collision occurs, neither STA4 nor STA5 can receive the ACK, and the data transmission will fail. In this case, STA4 and STA5 can select a random backoff count value after doubling the CW value and perform the countdown.STA1 waits while the medium is occupied by the transmissions of STA4 and STA5. However, when the medium becomes idle, after waiting for only DIFS, when the remaining backoff time has elapsed, it can start frame transmission.

[0065] As shown in the example of FIG. 4, a data frame is a frame used for transmitting data to be forwarded to the upper layer, and may be transmitted after a backoff that occurs after the elapse of DIFS since the medium became idle. Further, a management frame is a frame used for exchanging management information that is not forwarded to the upper layer, and is transmitted after a backoff that occurs after the elapse of an IFS such as DIFS or PIFS (Point coordination function IFS). As subtypes of management frames, there are Beacon, Association request / response, re-Association request / response, probe request / response, authentication request / response, etc. A control frame is a frame used for controlling access to the medium. As subtypes of control frames, there are RTS (Request-To-Send), CTS (Clear-To-Send), ACK (Acknowledgment), PS-Poll (Power Save-Poll), BlockAck, BlockACKReq (Block ACK request), NDP announcement (null data packet announcement), Trigger, etc. A control frame is transmitted after a backoff that occurs after the elapse of DIFS when it is not a response frame to a previous frame, and is transmitted without a backoff after the elapse of SIFS (short IFS) when it is a response frame to a previous frame. The type and subtype of a frame may be identified by the type field and subtype field in the frame control (FC) field.

[0066] A QoS (Quality of Service) STA can transmit a frame after a backoff that occurs after the expiration of AIFS (Arbitration IFS) for the access category (AC) to which the frame belongs, that is, AIFS[i] (where i is a value determined by the AC). Here, the frames for which AIFS[i] can be used can be data frames, management frames, or control frames that are not response frames.

[0067] FIG. 5 is a diagram for explaining a CSMA / CA-based frame transmission operation to which the present disclosure is applicable.

[0068] As described above, the CSMA / CA mechanism includes virtual carrier sensing in addition to physical carrier sensing in which a STA directly senses the medium. Virtual carrier sensing is for complementing problems that may occur in medium access, such as the hidden node problem. For virtual carrier sensing, the MAC of a STA can use a NAV (Network Allocation Vector). The NAV is a value that indicates to other STAs the time remaining until the medium becomes available for a STA that is currently using the medium or has the authority to use it. Therefore, the value set as the NAV corresponds to the period during which the use of the medium is planned by the STA that transmits the frame, and the STA that receives the NAV value is prohibited from accessing the medium during that period. For example, the NAV may be set based on the value of the "duration" field in the MAC header of the frame.

[0069] In the example of FIG. 5, assume that STA1 is about to transmit data to STA2, and STA3 is in a position where it can overhear some or all of the frames transmitted and received between STA1 and STA2.

[0070] In the CSMA / CA-based frame transmission operation, a mechanism using RTS / CTS frames may be applied to reduce the possibility of transmission collisions among multiple STAs. In the example of FIG. 5, while the transmission of STA1 is in progress, as a result of the carrier sensing of STA3, it may be determined that the medium is idle. That is, STA1 may be a hidden node to STA3. Or, in the example of FIG. 5, while the transmission of STA2 is in progress, as a result of the carrier sensing of STA3, it may be determined that the medium is idle. That is, STA2 may be a hidden node to STA3. Before data transmission and reception between STA1 and STA2, by exchanging RTS / CTS frames, STAs outside the transmission range of either STA1 or STA2, or STAs outside the carrier sensing range for transmissions from STA1 or STA3, can be prevented from attempting to occupy the channel during the data transmission and reception between STA1 and STA2.

[0071] Specifically, STA1 can use carrier sensing to determine whether the channel is in use. In terms of physical carrier sensing, STA1 can determine the channel occupancy idle state based on the energy magnitude or signal correlation detected from the channel. Also, in terms of virtual carrier sensing, STA1 can use the NAV (network allocation vector) timer to determine the occupancy state of the channel.

[0072] When the channel is idle at DIFS, STA1 can transmit an RTS frame to STA2 after performing backoff. When STA2 receives the RTS frame, it can transmit a CTS frame, which is a response to the RTS frame, to STA1 after SIFS.

[0073] Although STA3 cannot overhear the CTS frame from STA2, if it can overhear the RTS frame from STA1, STA3 can set the NAV timer for the subsequent consecutive frame transmission period (e.g., SIFS + CTS frame + SIFS + data frame + SIFS + ACK frame) using the duration information contained in the RTS frame. Or, although STA3 cannot overhear the RTS frame from STA1, if it can overhear the CTS frame from STA2, STA3 can set the NAV timer for the subsequent consecutive frame transmission period (e.g., SIFS + data frame + SIFS + ACK frame) using the duration information contained in the CTS frame. That is, when STA3 can overhear one or more of the RTS or CTS frames from at least one of STA1 or STA2, it can set the NAV based on this. If STA3 receives a new frame before the NAV timer expires, it can update the NAV timer using the duration information contained in the new frame. STA3 does not attempt channel access until the NAV timer expires.

[0074] When STA1 receives a CTS frame from STA2, it can transmit a data frame to STA2 after SIFS from the time when the reception of the CTS frame is completed. When STA2 successfully receives the data frame, it can transmit an ACK frame, which is a response to the data frame, to STA1 after SIFS. When the NAV timer of STA3 expires, it can determine whether the channel is in use using carrier sensing. If STA3 determines that the channel is not used by other terminals during the period from the expiration of the NAV timer to DIFS, it can attempt channel access after the contention window (CW) by random backoff has passed.

[0075] FIG. 6 is a diagram for explaining an example of a frame structure used in a wireless LAN system to which the present disclosure is applicable.

[0076] By an instruction or primitive (meaning a set of an instruction or parameters) from the MAC layer, the PHY layer can prepare an MPDU (MAC PDU) to be transmitted. For example, when receiving an instruction from the MAC layer requesting the start of transmission in the PHY layer, the PHY layer can switch to the transmission mode and configure and transmit the information (e.g., data) provided from the MAC layer in the form of a frame. Also, in the PHY layer, when detecting a valid preamble of a received frame, the PHY layer monitors the preamble header and sends an instruction to the MAC layer notifying the start of reception in the PHY layer.

[0077] As described above, information transmission / reception in a wireless LAN system is performed in the form of a frame, and for this purpose, a Physical layer Protocol Data Unit (PPDU) frame format is defined.

[0078] A basic PPDU may include an STF (Short Training Field), an LTF (Long Training Field), a SIG (SIGNAL) field, and a Data field. The most basic (e.g., non-HT (High Throughput) as shown in FIG. 7) PPDU format may be composed of only an L-STF (Legacy-STF), an L-LTF (Legacy-LTF), an L-SIG (Legacy-SIG) field, and a Data field. Also, depending on the type of PPDU format (e.g., HT-mixed format PPDU, HT-greenfield format PPDU, VHT (Very High Throughput) PPDU, etc.), additional (or other types of) RL-SIG, U-SIG, non-legacy SIG fields, non-legacy STF, non-legacy LTF (i.e., xx-SIG, xx-STF, xx-LTF (e.g., xx is HT, VHT, HE, EHT, etc.)) may be included between the L-SIG field and the Data field. More specific matters will be described later with reference to FIG. 7.

[0079] The STF is a signal for signal detection, AGC (Automatic Gain Control), diversity selection, precise time synchronization, etc., and the LTF is a signal for channel estimation, frequency error estimation, etc. It can be said that the STF and the LTF are signals for synchronization and channel estimation of the OFDM physical layer.

[0080] The SIG field may contain various information related to PPDU transmission and reception. For example, the L-SIG field is composed of 24 bits, and the L-SIG field may include a 4-bit Rate field, a 1-bit Reserved bit, a 12-bit Length field, a 1-bit Parity field, and a 6-bit Tail field. The RATE field may contain information regarding the modulation and coding rate of the data. For example, the 12-bit Length field may contain information regarding the length or time duration of the PPDU. For example, the value of the 12-bit Length field may be determined based on the type of the PPDU. For example, for non-HT, HT, VHT, or EHT PPDUs, the value of the Length field may be determined to be a multiple of 3. For example, for HE PPDUs, the value of the Length field may be determined to be a multiple of 3 + 1 or a multiple of 3 + 2.

[0081] The data field may include a SERVICE field, a PSDU (Physical layer Service Data Unit), PPDU TAIL bits, and, if necessary, padding bits. Some bits of the SERVICE field may be used for the synchronization of the descrambler at the receiving end. The PSDU corresponds to the MAC PDU defined at the MAC layer and may include data generated / used at the upper layer. The PPDU TAIL bits may be used to return the encoder to the 0 state. The padding bits may be used to align the length of the data field to a predetermined unit.

[0082] The MAC PDU is defined by various MAC frame formats, and the basic MAC frame is composed of a MAC header, a frame body, and an FCS (Frame Check Sequence). The MAC frame is composed of MAC PDUs and may be transmitted / received by the PSDU in the data part of the PPDU format.

[0083] The MAC header includes a Frame Control field, a Duration / ID field, an Address field, etc. The Frame Control field may include control information necessary for frame transmission / reception. The Duration / ID field may be set to the time for transmitting the frame, etc. The address sub-field can indicate the receiver address, transmitter address, destination address, and source address of the frame, and some address sub-fields may be omitted. It includes Sequence Control, QoS Control, and HT Control sub-fields. For the specific content of each sub-field of the MAC header, reference can be made to the IEEE 802.11 standard document.

[0084] The Null Data PPDU (NDP) format means a PPDU format that does not include a data field. That is, NDP means a frame format that includes PPDU preambles (i.e., L-STF, L-LTF, L-SIG fields, and, if present, further non-legacy SIG, non-legacy STF, non-legacy LTF) in the general PPDU format and does not include the remaining part (i.e., the data field).

[0085] FIG. 7 is a diagram showing an illustration of a PPDU defined in the IEEE 802.11 standard to which the present disclosure is applicable.

[0086] In standards such as IEEE 802.11a / g / n / ac / ax, various forms of PPDUs are used. The basic PPDU format (IEEE 802.11a / g) includes L-LTF, L-STF, L-SIG, and Data fields. The basic PPDU format can also be referred to as the non-HT PPDU format (FIG. 7(a)).

[0087] The HT PPDU format (IEEE 802.11n) further includes the HT-SIG, HT-STF, and HT-LFT(s) fields in the basic PPDU format. The HT PPDU format shown in Figure 7(b) can be referred to as the HT-mixed format. An HT-greenfield format PPDU may be further defined, which corresponds to a format composed of HT-GF-STF, HT-LTF1, HT-SIG, one or more HT-LTFs, and a Data field without including L-STF, L-LTF, and L-SIG (not shown).

[0088] An example of the VHT PPDU format (IEEE 802.11ac) further includes the VHT SIG-A, VHT-STF, VHT-LTF, and VHT-SIG-B fields in the basic PPDU format (Figure 7(c)).

[0089] An example of the HE PPDU format (IEEE 802.11ax) further includes the RL-SIG (Repeated L-SIG), HE-SIG-A, HE-SIG-B, HE-STF, HE-LTF(s), and PE (Packet Extension) fields in the basic PPDU format (Figure 7(d)). Depending on the detailed illustration of the HE PPDU format, some fields may be excluded or their lengths may change. For example, the HE-SIG-B field is included in the HE PPDU format for multi-user (MU), and the HE-SIG-B is not included in the HE PPDU format for single-user (SU). Also, the HE trigger-based (TB) PPDU format does not include the HE-SIG-B, and the length of the HE-STF field may change to 8 us. The HE ER (Extended Range) SU PPDU format does not include the HE-SIG-B field, and the length of the HE-SIG-A field may change to 16 us. For example, RL-SIG may be configured identically to L-SIG. The receiving STA can determine that the received PPDU is an HE PPDU or an EHT PPDU described later based on the presence of RL-SIG.

[0090] The EHT PPDU format may include the EHT MU (multi-user) of FIG. 7(e) and the EHT TB (trigger-based) PPDU of FIG. 7(f). The EHT PPDU format is similar to the HE PPDU format in that it includes an RL-SIG following the L-SIG, but may include a U (universal)-SIG, an EHT-SIG, an EHT-STF, and an EHT-LTF following the RL-SIG.

[0091] The EHT MU PPDU of FIG. 7(e) corresponds to a PPDU that carries one or more data (or PSDUs) for one or more users. That is, the EHT MU PPDU may be used for either SU transmission or MU transmission. For example, the EHT MU PPDU may correspond to a PPDU for one receiving STA or multiple receiving STAs.

[0092] The EHT TB PPDU of FIG. 7(f) omits the EHT-SIG compared to the EHT MU PPDU. A STA that receives a trigger for UL MU transmission (e.g., a trigger frame or TRS (triggered response scheduling)) can perform UL transmission based on the EHT TB PPDU format.

[0093] The L-STF, L-LTF, L-SIG, RL-SIG, U-SIG (Universal SIGNAL), and EHT-SIG fields may be encoded and modulated so that they can also be demodulated and decoded in a legacy STA, and may be mapped based on a defined 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 may be encoded and modulated so that they can be demodulated and decoded by a STA that has successfully decoded a non-legacy SIG (e.g., U-SIG and / or EHT-SIG) and obtained the information contained in the field, and may be mapped based on a defined subcarrier frequency interval (e.g., 78.125 kHz). These can be referred to as EHT modulated fields.

[0094] 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 modulated fields, and the HE-STF, HE-LTF, Data, and PE fields can be referred to as HE modulated fields. Also, in the VHT PPDU format, the L-STF, L-LTF, L-SIG, and VHT-SIG-A fields can be referred to as pre-VHT modulated fields, and the VHT STF, VHT-LTF, VHT-SIG-B, and Data fields can be referred to as VHT modulated fields.

[0095] The U-SIG included in the EHT PPDU format of FIG. 7 may be configured based on, for example, 2 symbols (e.g., 2 consecutive OFDM symbols). Each symbol (e.g., OFDM symbol) for the U-SIG may have a duration of 4 us, and the U-SIG may have an overall duration of 8 us. Each symbol of the U-SIG may be used to transmit 26-bit information. For example, each symbol of the U-SIG may be transmitted and received based on 52 data tones and 4 pilot tones.

[0096] The U-SIG may be configured in units of 20 MHz. For example, when an 80 MHz PPDU is configured, the same U-SIG may be replicated in units of 20 MHz. That is, the same four U-SIGs may be included in the 80 MHz PPDU. When the bandwidth exceeds 80 MHz, for example, for a 160 MHz PPDU, the U-SIG of the first 80 MHz unit and the U-SIG of the second 80 MHz unit may be different from each other.

[0097] In the U-SIG, for example, A uncoded bits may be transmitted. The first symbol of the U-SIG (for example, the U-SIG-1 symbol) may transmit the first X bits of the total A-bit information, and the second symbol of the U-SIG (for example, the U-SIG-2 symbol) may transmit the remaining Y bits of the total A-bit information. The A-bit information (for example, 52 uncoded bits) may include a CRC field (for example, a 4-bit field) and a tail field (for example, a 6-bit field). The tail field may be used to terminate the trellis of the convolutional decoder and may be set to 0, for example.

[0098] The A-bit information transmitted by the U-SIG can be distinguished into version-independent bits and version-dependent bits. For example, the U-SIG may be included in a new PPDU format (for example, the UHR PPDU format) not shown in FIG. 7. In the format of the U-SIG field included in the EHT PPDU format and the format of the U-SIG field included in the UHR PPDU format, the version-independent bits may be the same, and some or all of the version-dependent bits may be different.

[0099] For example, the size of the version-independent bits of U-SIG may be fixed or variable. The version-independent bits may be assigned only to U-SIG-1 symbols, or may be assigned to both U-SIG-1 symbols and U-SIG-2 symbols. The version-independent bits and the version-dependent bits may be called by various names such as the first control bit and the second control bit.

[0100] For example, the version-independent bits of U-SIG may include a 3-bit physical layer version identifier, and this information can indicate the PHY version of the transmitted and received PPDU (e.g., EHT, UHR, etc.). 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 of the UL / DL flag field is related to DL communication. The version-independent bits of U-SIG may include information regarding the length of the TXOP (transmission opportunity) and information regarding the BSS color ID.

[0101] For example, the version-dependent bits of U-SIG may include information that directly or indirectly indicates the type of PPDU (e.g., SU PPDU, MU PPDU, TB PPDU, etc.).

[0102] The information necessary for the transmission and reception of PPDU may be included in U-SIG. For example, U-SIG may further include information regarding bandwidth, information regarding the MCS method applied to non-legacy SIG (e.g., EHT-SIG or UHR-SIG, etc.), information indicating whether a DCM (dual carrier modulation) method (e.g., reusing the same signal on two subcarriers) is applied to achieve an effect similar to frequency diversity for non-legacy SIG, information regarding the number of symbols used for non-legacy SIG, information regarding whether non-legacy SIG is generated across the entire band, etc.

[0103] Some of the information necessary for PPDU transmission and reception may be included in the U-SIG and / or non-legacy SIG (e.g., EHT-SIG or UHR-SIG, etc.). For example, information regarding the type of non-legacy LTF / STF (e.g., EHT-LTF / EHT-STF or UHR-LTF / UHR-STF, etc.), information regarding the length of the non-legacy LTF and the CP (cyclic prefix) length, information regarding the GI (guard interval) applied to the non-legacy LTF, information regarding preamble puncturing applicable to the PPDU, information regarding RU (resource unit) allocation, etc. may be included only in the U-SIG, may be included only in the non-legacy SIG, or may be indicated by a combination of the information included in the U-SIG and the information included in the non-legacy SIG.

[0104] Preamble puncturing can mean the transmission of a PPDU where there is no signal present in one or more frequency units in the bandwidth of the PPDU. For example, the size of the frequency unit (or the resolution of the preamble puncturing) may be defined as 20 MHz, 40 MHz, etc. For example, preamble puncturing may be applied to a PPDU bandwidth of a predetermined size or more.

[0105] In the example of FIG. 7, non-legacy SIGs such as HE-SIG-B and EHT-SIG may include control information for the receiving STA. The non-legacy SIG may be transmitted in at least one symbol, and one symbol may have a length of 4 us. Information regarding the number of symbols used for the EHT-SIG may be included in a previous SIG (e.g., HE-SIG-A, U-SIG, etc.).

[0106] Non-legacy SIGs such as HE-SIG-B and EHT-SIG may include a common field and a user-specific field. The common field and the user-specific field may be coded individually.

[0107] In some cases, the common field may be omitted. For example, the common field may be omitted in a compression mode where non-OFDMA (orthogonal frequency multiple access) is applied, and multiple STAs can receive a PPDU (e.g., the data field of the PPDU) in the same frequency band. In a non-compression mode where OFDMA is applied, multiple users can receive a PPDU (e.g., the data field of the PPDU) in individual frequency bands.

[0108] The number of user-specific fields may be determined based on the number of users. One user block field may include at most two user fields. Each user field may be related to MU-MIMO allocation or non-MU-MIMO allocation.

[0109] The common field may include CRC bits and Tail bits. The length of the CRC bits may be determined to be 4 bits, and the length of the Tail bits may be determined to be 6 bits and may be set to 000000. The common field may include RU allocation information. The RU allocation information may include information regarding the location of the RUs allocated to multiple users (i.e., multiple receiving STAs).

[0110] An RU may include a plurality of subcarriers (or tones). The RU may be used when transmitting signals to a plurality of STAs based on the OFDMA technique. Also, the RU may be defined even when transmitting a signal to one STA. Resources may be allocated in units of RU for the non-legacy STF, non-legacy LTF, and Data fields.

[0111] The RU of an applicable size may be defined by the PPDU bandwidth. The RU may be defined to be the same or different for the applicable PPDU format (e.g., HE PPDU, EHT PPDU, UHR PPDU, etc.). For example, in the case of an 80 MHz PPDU, the RU arrangements of the HE PPDU and the EHT PPDU may be different from each other. The size of the applicable RU, the number of RUs, the RU position, the DC (direct current) subcarrier position and number, the null subcarrier position and number, the guard subcarrier position and number, etc. for each PPDU bandwidth can be referred to as a tone-plan. For example, the tone-plan for a wide bandwidth may be defined in the form of multiple repetitions of the tone-plan for a low bandwidth.

[0112] RUs of various sizes may be defined such as 26-tone RU, 52-tone RU, 106-tone RU, 242-tone RU, 484-tone RU, 996-tone RU, 2×996-tone RU, 4×996-tone RU, etc. An MRU (multiple RU) is distinguished from a plurality of individual RUs and corresponds to a group of subcarriers composed of a plurality of RUs. For example, one MRU may be defined as 52 + 26 tones, 106 + 26 tones, 484 + 242 tones, 996 + 484 tones, 996 + 484 + 242 tones, 2×996 + 484 tones, 3×996 tones, or 3×996 + 484 tones. Also, the plurality of RUs constituting one MRU may or may not be continuous in the frequency domain.

[0113] The specific size of the RU may be reduced or expanded. Therefore, in the present disclosure, the specific size of each RU (i.e., the number of corresponding tones) is illustrative rather than restrictive. Also, in the present disclosure, within a predetermined bandwidth (e.g., 20, 40, 80, 160, 320 MHz,...), the number of RUs may vary depending on the size of the RU.

[0114] In the PPDU format of FIG. 7, the names of the respective fields are illustrative and the scope of the present disclosure is not limited by the names. Also, the examples of the present disclosure may be applied to new PPDU formats in which some fields are excluded and / or some fields are added based on the PPDU format illustrated in FIG. 7 in addition to the PPDU format illustrated in FIG. 7.

[0115] Multi-link operation

[0116] Hereinafter, the multi-link (ML) operation supported by the STA according to the present disclosure will be described.

[0117] The STA (AP STA and / or non-AP STA) described in the present disclosure can support multi-link (ML) communication. ML communication can mean communication that supports a plurality of links. The links related to ML communication may include channels (e.g., 20 / 40 / 80 / 160 / 240 / 320 MHz channels) in the frequency bands in which the STA operates (e.g., 2.4 GHz band, 5 GHz band, 6 GHz band, etc.). The plurality of links used for ML communication may be set in various ways. For example, the plurality of links supported by one STA for ML communication may belong to the same frequency band or may belong to different frequency bands. Also, each link may correspond to a frequency unit of a predetermined size (e.g., channel, sub-channel, RU, etc.). Also, some or all of the plurality of links may be frequency units of the same size as each other or may be frequency units of different sizes from each other.

[0118] When one STA supports multiple links, the transmit-receive devices that support each link may operate as one logical STA. That is, an MLD is a logical entity that has one or more affiliated STAs and means a device that has a single MAC service access point (SAP) for one MAC data service and logical link control (LLC). A non-AP MLD means an MLD in which each STA belonging to the MLD is a non-AP STA. A multi-radio non-AP MLD means a non-AP MLD that supports receiving or exchanging frames on one or more links at a time. An AP MLD means an MLD in which each STA belonging to the MLD is an AP STA.

[0119] Multi-link operation (MLO) enables a non-AP MLD to perform discovery, authentication, association, and set up multiple links with an AP MLD. Based on the supported capabilities exchanged during the association procedure, each link can enable channel access and frame exchange between the non-AP MLD and the AP MLD. STAs affiliated with an MLD can select and manage their own capabilities and operating parameters independently of other STAs belonging to the same MLD.

[0120] During the multi-link setup process, the AP MLD and / or non-AP MLD can transmit and receive link-related information that the MLD can support. The link-related information may include one or more of the following: the presence or absence of simultaneous transmit and receive (STR) operations or non-simultaneous transmit and receive (NSTR) operations that can be supported by the MLD on multiple links, information regarding the number / upper limit of UL / DL links, information regarding the location / bandwidth / resources of UL / DL links, information regarding the frame type (e.g., management, control, data, etc.) that can be used or preferred on at least one UL / DL link, information regarding the ACK policy that can be used or preferred on at least one UL / DL link, or information regarding the traffic identifier (TID) that can be used on at least one UL / DL link.

[0121] The AP MLD (e.g., NSTR mobile AP MLD) can set one of the multiple links as the primary link. The AP MLD can perform beacon frames, probe response frames, and group addressed data frames only on the primary link. The remaining other links of the multiple links can be set as non-primary links. The AP MLD operating on a non-primary link can also operate so as not to transmit beacon frames or probe response frames. Also, the non-AP MLD can perform frame exchanges only on the primary link during authentication, (re)association, and 4-way handshaking.

[0122] In the multi-link setup process, when at least one TID (traffic identifier) is mapped to the link, the setup link is defined as enabled, and when there is no TID mapped to the link, the setup link may be defined as disabled. The TID must always be mapped to one or more setup links unless admission control is used. Basically, since the TID is mapped to all setup links, all setup links may be enabled.

[0123] When the link is enabled, the link may be used for frame exchange depending on the power state of the non-AP STA operating on the link. Only an MSDU or A-MSDU with a TID mapped to the enabled link may be transmitted on the link. Management frames and control frames may be transmitted only on the enabled link.

[0124] When the link is disabled, the link may include management frames for both DL and UL and may not be used for frame exchange.

[0125] In the multi-link setup process, the activation / deactivation of each link can be indicated by TID-to-Link mapping. The TID-to-Link mapping may be performed in the default mapping mode or / and the negotiation mapping mode.

[0126] Access point (AP) related information in multi-link operation

[0127] One of the STAs belonging to the MLD can provide information about one or more links other than the link where it is located for multi-link discovery (e.g., obtaining information about a plurality of links including the link on one link) or multi-link setup (e.g., simultaneously associating on a plurality of links by exchanging association request / response frames on one link). A multi-link (ML) element may be defined to provide such information.

[0128] FIG. 8 illustrates the structure of an ML element to which the present disclosure is applicable.

[0129] In the ML element (or ML information element (IE)) of FIG. 8(a), the element ID field and the element ID extension field have specific values (e.g., 255 and 107) indicating that it is an ML element, and the length field may have a value indicating the length of the remaining fields excluding the element ID field and the length field (e.g., in octets).

[0130] Figure 8(b) shows an exemplary format of the multi-link control field of Figure 8(a). For example, the multi-link control field may be defined as 2 octets in size 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 types such as basic, probe request, reconfiguration, TDLS (tunneled direct-link setup), priority access, etc. The presence bitmap subfield indicates the presence or absence of various subfields within the common info field and may be defined with different formats depending on various variants (or types as described above) of the ML elements.

[0131] Figure 8(c) shows an exemplary format of the common info field of Figure 8(a). The common info field may be defined with a variable size. The common info length subfield can indicate the number of octets included in the common info field (including one octet of the common info length subfield). The 6-octet MLD MAC address subfield may have a value that identifies the MAC address of the MLD to which the STA transmitting the basic ML element belongs. Additionally, each of the link ID info subfield, BSS parameter change count subfield, medium synchronization delay information subfield, EML (enhanced multi-link) capability subfield, MLD capabilities and operations subfield, AP MLD ID subfield, extended MLD capabilities and operations subfield, etc. may or may not be included in the common info field.

[0132] The link info field of FIG. 8(a) may be defined with a variable size, may include link identification information, and may optionally exist. When the link info field exists, it may include one or more subelements. The format and order of the subelements may be defined in various ways. As examples of selective subelement IDs for the basic variant ML element, the value of subelement ID 0 corresponds to the name of the per-STA profile, is extensible, the value of subelement ID 221 corresponds to the vendor-specific name, and the extensibility may be determined by the vendor, the value of subelement ID 254 corresponds to the name of the fragment and is not extensible, and the remaining 1-220, 222-253, and 255 may be reserved.

[0133] FIG. 8(d) shows an exemplary format of the per-STA profile subelement. The per-STA profile subelement may include a 1-octet subelement ID subfield, a 1-octet length subfield, a 2-octet STA control subfield, a variable-size STA info subfield, and a variable-size STA profile subfield. The STA control subfield may include information such as the link ID, whether a complete profile is included, and the presence or absence of the STA MAC address. The STA info subfield may include information such as the STA MAC address. The STA profile subfield 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., depending on whether the reported STA is an AP STA or a non-AP STA.

[0134] The format of the ML element in FIG. 8 is exemplary, and the order, name, size, etc. of the fields / sub-fields may be changed, additional fields / sub-fields may be further defined, and some fields / sub-fields may be excluded. In short, the common information field includes information common among STAs in the MLD, and the link information field may include specific information for each STA / link (e.g., in the profile sub-element for each STA including the link ID corresponding to the STA).

[0135] FIG. 9 is a diagram showing an exemplary relationship between a multiple BSSID set and a multi-link device to which the present disclosure is applicable.

[0136] The multiple BSSID operation may include that one physical access point (AP) generates and operates multiple virtual APs on one channel. In the following description, the multiple BSSID can be denoted as MBSSID.

[0137] The MBSSID set may include one or more non-transmitted BSSIDs, and one transmitted BSSID may be defined.

[0138] In the example of FIG. 9, x, y, p, q, r, a, b correspond to exemplary values of BSSIDs, [T] represents the transmitted BSSID (or, Tx BSSID), and the BSSID without [T] displayed represents the non-transmitted BSSID (or, non-Tx BSSID).

[0139] In the example of FIG. 9, when considering the MBSSID operation and the ML operation simultaneously, any BSSID within one MBSSID set may belong to an MLD, and each of the multiple links belonging to one MLD may correspond to one channel (or the BSSID operating on that channel). Different MLDs can operate on multiple links on the same or different channels from each other. For example, link 0 (L0), link 1 (L1), and link 2 (L2) of MLD1 may be set on CH1, CH2, and CH3, respectively. For example, L0 and L1 of MLD2 may be set on CH2 and CH3, respectively. For example, L0 and L1 of MLD3 may be set on CH1 and CH2, respectively. BSSID-c does not have to belong to an MLD.

[0140] FIG. 10 is a diagram for explaining an example of the ML element of the MBSSID element to which the present disclosure is applicable.

[0141] Information for multiple (virtual) APs can be provided included in one management frame (for example, beacon, probe response, (re)association response), and for this purpose, an MBSSID element (or an MBSSID information element (IE)) may be defined.

[0142] For example, in the example of FIG. 9, BSSID-a of MLD1 belongs to the MBSSID set on CH3 and may correspond to the Tx BSSID of the MBSSID set. The Tx BSSID (for example, BSSID-a) can use the MBSSID element included in the management frame (for example, beacon, probe response, (re)association response frame) containing its own information to provide information about non-Tx BSSIDs such as BSSID-b and BSSID-c to the STA together. Here, BSSID-c does not belong to an MLD, but BSSID-b belongs to MLD2. The MBSSID element included in the management frame transmitted by BSSID-a may include an ML element in the profile of the AP corresponding to non-Tx BSSID BSSID-b.

[0143] For example, in a probe response frame or a beacon frame that is not a multi-link (ML) probe response frame transmitted by a Tx BSSID, an ML element (e.g., a basic ML element carrying information about an AP MLD to which an AP corresponding to a non-Tx BSSID belongs) may be included in the non-Tx BSSID profile within the MBSSID element. Alternatively, in an ML probe response transmitted by a Tx BSSID, the ML element may be included in the body part of the ML probe response (which is not an MBSSID element). Alternatively, in a probe response frame or a beacon frame that is not an ML probe response frame, when an AP corresponding to the non-Tx BSSID profile in the MBSSID element belongs to an MLD, the ML element in the non-Tx BSSID profile may include a common information field and may not include a per-STA profile that is information about an AP on another link of the MLD. Alternatively, the ML element included in the body part of the ML probe response (which is not an MBSSID element) in an ML probe response may include a per-STA profile field that is information about an AP on another link of the MLD. In the illustration of FIG. 10, the ML element is described as being included within the MBSSID element, but the illustration of the present disclosure is also applicable when the ML element is included in the body part of the ML probe response frame.

[0144] Specifically, FIG. 10 corresponds to an illustration of inheritance of a complete per-STA profile for an MBSSID scenario. For example, in FIG. 10, the inheritance is illustrated when the per-STA profile carries a complete profile in the basic ML element included in the non-Tx BSSID profile of the MBSSID element. This illustration shows management frames transmitted by an AP corresponding to the Tx BSSID. The management frames carry one or more elements each having an element ID, and the element IDs are shown as A, B, C,... within parentheses. The frame also carries an MBSSID element including a profile for the Non-Tx BSSID N. The Non-Tx BSSID profile includes a basic ML element carrying a complete profile for the AP x. BSSID N inherits elements having the IDs of B, C, and E. Elements having the IDs of D and F are specific to BSSID N and appear in its non-Tx BSSID profile. Also, BSSID N does not inherit the element having the ID of A and the elements included in the non-inheritance elements. Since the value of element F for BSSID N is not the same as that advertised by the Tx BSSID, the element is included in the profile for BSSID N. The element having the ID of Y is specific to BSSID N and is included in its profile. AP x inherits elements having the IDs of D and F from BSSID N and indirectly (e.g., through inheritance of BSSID N) inherits the element having the ID of C from the Tx BSSID. AP x does not inherit element A (which is the same as the non-Tx BSSID). Elements having the IDs of B and Y are specific to AP x and are included in its profile. Also, AP x does not inherit element E from the Tx BSSID and does not inherit the IDs included in the non-inheritance elements present in its profile.

[0145] That is, as described above, one AP within one MLD can include information of other APs within the same MLD in the ML element and transmit it to the STA. Also, when an MBSSID set and an MLD are mixed as exemplified in FIG. 9, the ML element may be included in the MBSSID element and provided from the AP to the STA.

[0146] Here, since the ML element basically includes information for various APs, it may exceed 255 octets when the number of AP STAs is large and / or the number of inherited elements is small. Generally, fragmentation may be applied to elements exceeding 255 octets, but for the MBSSID element, fragmentation is basically not applied, and when fragmentation is applied to the non-Tx BSSID profile, a plurality of MBSSID elements may be used.

[0147] That is, when the ML element is included in the non-Tx BSSID, when fragmentation for the MBSSID element is allowed, hierarchical fragmentation for a plurality of (sub) elements is required, which requires complex rules and may make the decoding of the MBSSID element (based on fragmentation) received by the non-AP STA from the AP STA difficult.

[0148] Regarding this, fragmentation can also be prevented by defining and applying the MLD ID. For example, the MLD ID of the MLD to which the non-Tx BSSID belongs is included in the (basic) ML element included in a request frame (e.g., a probe request frame, an ML (multi-link) probe request frame, a (re) association request frame) from the STA, and complete profile information for the MLD may be requested. In this case, the information corresponding to the non-Tx BSSID is included in the non-Tx BSSID profile of the MBSSID element in the response frame (e.g., a probe response frame, an ML probe response frame, a (re) association response frame), and the information for other APs belonging to the same MLD as the reporting AP is included in each per-STA profile together with the signaling information for the MLD ID in the (basic) ML element that is not the MBSSID element of the response frame.

[0149] Here, the AP that transmits the response frame can be referred to as the reporting AP, and other APs belonging to the same MLD as the reporting AP can be referred to as the reported APs. The information for the reporting AP is included in the body of the response frame (i.e., the element of the response frame that is not included in the MBSSID element (i.e., outside the MBSSID element)), and the information for the reported AP may be included in the per-STA profile in the (basic) ML element of the response frame.

[0150] When complete profile information is requested by the request frame, inheritance rules may be applied between the information included in the frame body of the response frame (i.e., the element not included in the MBSSID element and / or the ML element) (i.e., the complete profile for the reporting AP) and the per-STA profile information in the (basic) ML element (i.e., the complete profile for each of the reported APs).

[0151] When there are reported AP information / elements that match the information / elements of the reporting AP, they may be omitted in the per-STA profile of the reported AP within the (basic) ML element, thus reducing overhead. Reported AP information / elements that do not match the information of the reporting AP, and / or information / elements (i.e., additional information / elements) not included in the body of the response frame corresponding to the information of the reporting AP (i.e., elements not included in the MBSSID element and / or ML element) may be included in the per-STA profile of the reported AP within the (basic) ML element. Also, when there are information / elements that do not apply to the reported AP in the information / elements of the reporting AP, it may be indicated by the non-inherited element which information / elements are not inherited.

[0152] Summarizing the inheritance rules described above, it is as follows. According to the inheritance rule for the MBSSID element, for multiple BSSIDs within the same MBSSID set, among the information of the non-Tx BSSID, the information that is the same as the information of the Tx BSSID is omitted, and the information different from the information of the Tx BSSID or additional information may be included in the MBSSID profile. Next, according to the inheritance rule for the (basic) ML element, for multiple APs within the same MLD, among the information of the reported AP, the information that is the same as the information of the reporting AP is omitted, and the information different from the information of the reporting AP or additional information may be included in the per-STA profile.

[0153] Such inheritance rules are applicable when the reporting AP and the reported AP belong to the same MLD. That is, inheritance rules applicable when the reporting AP and the reported AP belong to separate MLDs are not defined. As a result, without fragment application for the MBSSID element, a new scheme regarding inheritance for the AP to efficiently provide the (basic) ML element is required.

[0154] In the present disclosure, various examples for new inheritance rules applicable when the reporting AP and the reported AP belong to different MLDs and different MBSSID sets in a situation where MBSSIDs and MLDs coexist are described. For example, in the present disclosure, various examples for determining a reference for inheritance based on MLD and MBSSID sets including non-Tx BSSID and applying inheritance rules based thereon to efficiently provide information are described.

[0155] FIG. 11 is a diagram for explaining an example of a method by which a STA acquires information related to a plurality of APs according to the present disclosure.

[0156] In step S1110, the STA can transmit a request frame including information related to other APs / MLDs to the first AP. For example, the request frame may include information indicating one or more of the second AP or the first MLD. For example, the first AP may belong to the second MLD. For example, the first AP may be an AP corresponding to the transmitted (Tx) BSSID.

[0157] For example, the request frame may correspond to a probe request frame, an ML probe request frame, an association request frame, or a reassociation request frame.

[0158] In step S1120, the STA can receive, from the first AP, a response frame including information to which inheritance or non-inheritance based on a non-transmitted (non-Tx) BSSID profile is applied as a response to the request frame. For example, the response frame may include a per-STA profile for one or more STAs. Inheritance or non-inheritance for the per-STA profile for one or more STAs may be based on the non-Tx BSSID profile. That is, the non-Tx BSSID profile may be a reference for inheritance or non-inheritance. Also, the first AP may correspond to the reporting AP.

[0159] The profile of non-Tx BSSID as an inherited or non-inherited reference may be included in the Multiple BSSID (MBSSID) element. That is, the information (including the non-Tx BSSID profile among them) included in the MBSSID element contained in the response frame (i.e., the element not included in the MBSSID element), may be defined or applied as an inherited or non-inherited reference. For example, the profile of non-Tx BSSID may correspond to the profile of an AP belonging to the same MLD as the second AP (indicated by the request frame), or the profile of an AP belonging to the first MLD (indicated by the request frame).

[0160] For example, inheritance may include that for each profile of one or more STAs, the same information or elements as the profile of non-Tx BSSID (i.e., the inherited reference) are omitted.

[0161] For example, non-inheritance may include that for each profile of one or more STAs, one or more information or elements different from the profile for the AP corresponding to non-Tx BSSID (i.e., the non-inherited reference), or one or more information or elements not included in the profile for the AP corresponding to non-Tx BSSID (i.e., the non-inherited reference) are included. The information indicating the information or elements to be non-inherited in this way may be included in the non-inherited field in the response frame.

[0162] The profile for each one or more STAs may be included in the (basic) ML element. The (basic) ML element may be included in the MBSSID element or in the ML probe response. The (basic) ML element may include a complete per-STA profile for one or more reported APs.

[0163] For example, the response frame may correspond to a probe response frame, an ML probe response frame, an association response frame, or a reassociation response frame, etc.

[0164] The method described in the example of FIG. 11 may be performed by the first device 100 of FIG. 1. For example, one or more processors 102 of the first device 100 of FIG. 1 may be configured to transmit a request frame via one or more transceivers 106 and receive a response frame thereto. Note that one or more memories 104 of the first device 100 can store instructions for performing the method described in the example of FIG. 11 or the examples described later when executed by one or more processors 102.

[0165] FIG. 12 is a diagram for explaining an example of a method in which an AP provides information about a plurality of APs to a STA according to the present disclosure.

[0166] In step S1210, the first AP can receive a request frame including information related to other APs / MLDs from the STA. The other APs / MLDs may correspond to one or more of the second AP or the first MLD, and information indicating the other APs / MLDs may be included in the request frame. For example, the first AP may belong to the second MLD. For example, the first AP may be an AP corresponding to the Tx BSSID.

[0167] In step S1220, the first AP can transmit a response frame including information to which inheritance or non-inheritance based on the non-Tx BSSID profile is applied as a response to the request frame to the STA. For example, the response frame may include a profile for each one or more STAs, and the inheritance or non-inheritance thereto may be based on the non-Tx BSSID profile. That is, the non-Tx BSSID profile may be a reference for inheritance or non-inheritance. Also, the first AP may correspond to the reporting AP.

[0168] Specific matters regarding non-Tx BSSID-based inheritance or non-inheritance for the profiles for each one or more STAs included in the response frame, and examples of the request frame and the response frame are the same as those described in the example of FIG. 11, and the overlapping descriptions are omitted.

[0169] The method described in the example of FIG. 12 may be performed by the second device 200 of FIG. 1. For example, one or more processors 202 of the second device 200 of FIG. 1 may be configured to receive a request frame via one or more transceivers 206 and transmit a response frame thereto. Note that one or more memories 204 of the second device 200 can store instructions for performing the method described in the example of FIG. 12 or the examples described later when executed by one or more processors 202.

[0170] The examples of FIGS. 11 and 12 may correspond to a part of various examples of the present disclosure. Hereinafter, various examples of the present disclosure including the examples of FIGS. 11 and 12 will be described more specifically.

[0171] In the embodiments described later, probe request frames and probe response frames are described as representative examples to which the present disclosure is applied. However, the same application of the embodiments described later is also possible when the probe request / response frames are replaced with ML probe request / response frames, association request / response frames, reassociation request / response frames, or other management frames.

[0172] Example 1

[0173] As described above, when the STA requests information on the MLD to which the AP corresponding to the non-Tx BSSID belongs and some or all of the APs belonging thereto, the body part of the ML probe response transmitted by the AP corresponding to the Tx BSSID (that is, the elements not included in the MBSSID element and / or the ML element) includes the information of the Tx BSSID. The non-Tx BSSID profile of the MBSSID element in the ML probe response includes the information regarding the non-Tx BSSID, and the (basic) ML element in the MBSSID element or in the ML probe response may include information on other APs (for example, requested by the STA) belonging to the MLD to which the AP corresponding to the non-Tx BSSID belongs.

[0174] That is, with reference to the AP corresponding to the non-Tx BSSID, inheritance rules may be applied to the reported APs (for example, other APs belonging to the same MLD as the non-Tx BSSID) for each STA belonging to the (basic) ML element profile.

[0175] For example, the profile of the non-Tx BSSID belonging to the same MBSSID set as the reported AP (or, Tx BSSID), while belonging to the MLD requested by the STA, may be a reference for inheritance / non-inheritance applied to the response frame.

[0176] For example, while belonging to an MLD different from the MLD to which the reported AP belongs, and applying the information of the AP corresponding to the non-Tx BSSID belonging to the MBSSID set to which the reported AP belongs as a reference for inheritance / non-inheritance, information regarding other APs / BSSIDs may be provided to the STA by the response frame.

[0177] FIG. 13 shows an example of the application of non-Tx BSSID profile-based inheritance / non-inheritance according to the present disclosure.

[0178] In explaining the example of FIG. 13, referring to the example of FIG. 9 together, it is assumed that BSSID-q corresponding to the Tx BSSID among the MBSSID sets on CH2 corresponds to the AP that exchanges request / response frames with the STA, that is, the reporting AP. The request frame from the STA may include, for example, information indicating MLD1 as information indicating the target for which information is requested by the STA (that is, the AP to be reported). That is, the STA can request information of the AP belonging to MLD1 to BSSID-q belonging to MLD2. In this case, the inheritance / non-inheritance reference for the information included in the response frame may be the profile of BSSID-p belonging to MLD1 requested by the STA among the non-Tx BSSIDs of the MBSSID set (that is, the MBSSID set on CH2) to which the AP corresponding to the Tx BSSID belongs, rather than the profile of BSSID-q which is the Tx BSSID. The profile of BSSID-p may be included not in the body part of the response frame (that is, the element not included in the MBSSID element), but in the MBSSID element of the response frame.

[0179] Thus, the application of the inheritance rule may be based on the relationship between APs belonging to different MLDs. When providing information of an AP belonging to MLD1 to the STA, if the inheritance rule is applied with reference to the information of the AP belonging to MLD2, the probability of duplication of AP information may decrease. Therefore, the effect of reducing the overhead of the response frame, which is the purpose of applying the inheritance rule, may not be obtained.

[0180] Therefore, when requesting MLD information for a non-Tx BSSID, it is necessary to change the existing inheritance rule in order to efficiently apply the inheritance rule in the response thereto.

[0181] Basically, the inheritance rule can be applied by referring to the information existing in the non-Tx BSSID profile. That is, by referring to the AP corresponding to the non-Tx BSSID, the inheritance rule can be applied to the reported APs of the profile for each STA included in the (basic) ML element (i.e., the APs belonging to the same MLD as the AP corresponding to the non-Tx BSSID which is the reference).

[0182] Specifically, among the information / elements of the profile for each STA of the reported AP of the (basic) ML element, if there are information / elements that match the information / elements belonging to the non-Tx BSSID profile which is the reference, such information / elements can be omitted to reduce the overhead of the response frame.

[0183] Among the information / elements of the profile for each STA of the reported AP of the (basic) ML element, if there are information / elements that do not match the information / elements belonging to the non-Tx BSSID profile which is the reference, or if there are additional information / elements existing in the body part of the response frame or not existing in the non-Tx BSSID profile which is the reference, such information / elements may be included in the response frame.

[0184] Among the information / elements of the non-Tx BSSID profile which is the reference, if there are information / elements that do not match the information of the reported AP, the non-inherited elements included in the response frame can be used to indicate (e.g., in list form) which information / elements are not inherited.

[0185] In an existing wireless LAN system, the reference in the inheritance / non-inheritance rule applied to a response frame is the information / profile of the reporting AP (or, Tx BSSID) included in the body of the response frame (i.e., the elements not included in the MBSSID element), whereas the reference in the inheritance / non-inheritance rule according to various exemplary embodiments of the present disclosure may be the information / profile of the AP corresponding to the non-Tx BSSID. Thereby, when the STA provides information for the requested MLD, by using the profile of the non-Tx BSSID, which is likely to include information common to the information of the AP to which the MLD belongs, as the reference for inheritance / non-inheritance, the effect of reducing the overhead of the response frame can be efficiently achieved.

[0186] The embodiments described above are those in which the components and features of the present disclosure are combined in a predetermined form. Each component or feature should be considered as optional unless otherwise explicitly mentioned. Each component or feature may be implemented in a form that does not combine with other components or features. Also, it is possible to configure embodiments of the present disclosure by combining some components and / or features. The order of operations described in the embodiments of the present disclosure may be changed. Some configurations or features of one embodiment may be included in other embodiments, or may be replaced with corresponding configurations or features of other embodiments. It is obvious that embodiments can be configured by combining claims that do not have an explicit citation relationship in the claims, or can be included as new claims by amendment after filing.

[0187] It is obvious to those skilled in the art that the present disclosure can be embodied in other specific forms without departing from the essential features of the present disclosure. Therefore, the above detailed description should not be construed as restrictive in any way and should be considered as exemplary. The scope of the present disclosure should be determined by a reasonable interpretation of the appended claims, and any changes within the equivalent scope of the present disclosure are included in the scope of the present disclosure.

[0188] The scope of the present disclosure includes software or machine-executable instructions (e.g., operating systems, applications, firmware, programs, etc.) that cause operations according to the methods of various embodiments to be executed on a device or computer, and a non-transitory computer-readable medium on which such software or instructions are stored and executable on a device or computer. Instructions that can be used to program a processing system to execute the features described in the present disclosure may be stored on / within a storage medium or computer-readable storage medium, and the features described in the present disclosure may be implemented using a computer program product including such a storage medium. The storage medium can include, but is not limited to, high-speed random access memory such as DRAM, SRAM, DDR RAM, or other random access solid-state memory devices, and can include non-volatile memory such as one or more magnetic disk storage devices, optical disk storage devices, flash memory devices, or other non-volatile solid-state storage devices. The memory can optionally include one or more storage devices located remotely from the processor. The memory or, alternatively, the non-volatile memory device within the memory includes a non-transitory computer-readable storage medium. The features described in the present disclosure may be stored on any one of the machine-readable media, integrated with software and / or firmware that can control the hardware of the processing system and cause the processing system to interact with other mechanisms that utilize the results according to the embodiments of the present disclosure. Such software or firmware can include, but is not limited to, application code, device drivers, operating systems, and execution environments / containers.

Industrial Applicability

[0189] Although the method proposed in the present disclosure has been mainly described with examples applied to IEEE 802.11-based systems, it can also be applied to various wireless LANs or wireless communication systems other than IEEE 802.11-based systems.

Claims

1. A method performed by a station (STA) in a wireless LAN system, the method comprising: transmitting a request frame to a first access point (AP), the request frame including information related to one or more of a second access point (AP) or a first multi-link device (MLD); receiving a response frame for the request frame from the first AP, wherein the response frame includes a per-STA profile for each of one or more STAs, wherein inheritance or non-inheritance of the per-STA profile for each of the one or more STAs is based on a profile of a non-transmitted (non-Tx) basic service set identifier (BSSID).

2. The method of claim 1, wherein the profile of the non-Tx BSSID is included in a multi-BSSID (MBSSID) element.

3. The method of claim 2, wherein the per-STA profile for each of the one or more STAs is included in a multi-link (ML) element.

4. The method of claim 3, wherein the ML element includes a complete per-STA profile for one or more reported APs.

5. The method of claim 3, wherein the ML element is included in the response frame body outside the MBSSID element.

6. The method of claim 1, wherein the profile of the non-Tx BSSID corresponds to a profile of an AP belonging to the same MLD as the second AP or a profile of an AP belonging to the first MLD.

7. The method of claim 1, wherein the first AP affiliates with a second MLD.

8. The method of claim 1, wherein the first AP corresponds to a transmitted (Tx) BSSID.

9. The method of claim 1, wherein the inheritance includes omission of the same information or elements as in the profile of the non-Tx BSSID for each of the per-STA profiles for the one or more STAs.

10. The non-inheritance includes, for each of the one or more STAs and for each profile, one or more information or elements different from the profile for the AP corresponding to the non-Tx BSSID, or one or more information or elements not included in the profile for the AP corresponding to the non-Tx BSSID, the method according to claim 1.

11. The non-inheritance field in the response frame is the method according to claim 1, including information indicating one or more information or elements different from the profile for the AP corresponding to the non-Tx BSSID, or one or more information or elements not included in the profile for the AP corresponding to the non-Tx BSSID.

12. The request frame is one of a probe request frame, an ML probe request frame, an association request frame, or a reassociation request frame, the method according to claim 1, wherein the response frame is one of a probe response frame, an ML probe response frame, an association response frame, or a reassociation response frame.

13. A station (STA) device in a wireless LAN system, the device comprising one or more transceivers, and one or more processors coupled to the one or more transceivers, wherein the one or more processors are configured to transmit, via the one or more transceivers, a request frame including information related to one or more of a second access point (AP) or a first multi-link device (MLD) to a first access point (AP), and receive, from the first AP via the one or more transceivers, a response frame to the request frame, wherein the response frame includes a profile for each of one or more STAs, and the inheritance or non-inheritance for the profile for each of the one or more STAs is based on a profile of a non-transmitted (non-Tx) basic service set identifier (BSSID), the device.

14. A method performed by a first access point (AP) in a wireless LAN system, the method comprising receiving, from a station (STA), a request frame including information related to one or more of a second access point (AP) or a first multi-link device (MLD), and transmitting, to the STA, a response frame to the request frame. The response frame includes a profile for each of one or more STAs, and inheritance or non-inheritance for the profile for each of the one or more STAs is based on a profile of a non-transmitted (non-Tx) basic service set identifier (BSSID). **Claim 15** A first access point (AP) device in a wireless LAN system, the device comprising: one or more transceivers; one or more processors coupled to the one or more transceivers, wherein the one or more processors are configured to: receive, from a station (STA), a request frame including information related to one or more of a second access point (AP) or a first multi-link device (MLD) via the one or more transceivers; transmit, to the STA, a response frame for the request frame via the one or more transceivers, wherein the response frame includes a profile for each of one or more STAs, and inheritance or non-inheritance for the profile for each of the one or more STAs is based on a profile of a non-transmitted (non-Tx) basic service set identifier (BSSID). **Claim 16** A processing device configured to control a station (STA) in a wireless LAN system, the processing device comprising: one or more processors; one or more computer memories operably coupled to the one or more processors and storing instructions for performing the method according to any one of claims 1 to 12 based on execution by the one or more processors. **Claim 17** One or more non-transitory computer-readable media storing one or more instructions, wherein the one or more instructions are executed by one or more processors to control a device in a wireless LAN system to perform the method according to any one of claims 1 to 12.

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