Listen interval-based transmission or reception method and device for access point multi-link device supporting power saving in wireless LAN system

Abstract

Disclosed are a listen interval-based transmission or reception method and device for an access point (AP) multi-link device (MLD) supporting power saving (PS) in a wireless LAN system. The method according to an embodiment of the present disclosure may comprise the steps in which: a non-AP station (STA) affiliated with a non-AP MLD receives, from one or more APs affiliated with an AP MLD, at least one of first information related to whether a PS mode is supported or second information related to whether the PS mode is enabled; and the non-AP STA determines a listen interval on the basis of one or more beacon intervals related to the one or more APs.

Description

Listen interval-based transmission or reception method and device for a power-saving supported access point multi-link device in a wireless LAN system

[0001] The present disclosure relates to a transmission or reception method and apparatus based on a listen interval for an access point multi-link device (MLD) that supports power-save (PS) in a Wireless Local Area Network (WLAN) system.

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

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

[0004] The technical problem of the present disclosure is to provide a listening interval setting between an AP MLD and a non-AP MLD that supports access point (AP) power saving in a wireless LAN system, and a transmission or reception method and apparatus based thereon.

[0005] The technical problems to be solved in this disclosure are not limited to those mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art to which this disclosure belongs from the description below.

[0006] A method according to one aspect of the present disclosure may include: receiving one or more of first information or second information from one or more APs affiliated with an access point multi-link device (AP MLD) by a non-AP station (STA) affiliated with a non-AP multi-link device (non-AP MLD); and determining a listen interval by the non-AP STA based on one or more beacon intervals associated with the one or more APs. The first information may relate to the support of a power-saving (PS) mode of one or more links of the AP MLD. The second information may relate to the enable or disable of the PS mode of one or more links of the AP MLD. The one or more beacon intervals may include a specific beacon interval of a specific AP among the one or more APs based on one or more of the first information or the second information of the one or more APs.

[0007] A method according to a further aspect of the present disclosure may include: transmitting one or more of first information or second information to a non-AP station (STA) affiliated with a non-AP multi-link device (non-AP MLD) by a first AP affiliated with an access point multi-link device (AP MLD); and performing transmission or reception with the non-AP STA based on a listen interval based on one or more beacon intervals associated with one or more APs including the first AP affiliated with the AP MLD. The first information may relate to the support of a power-saving (PS) mode of the link of the first AP. The second information may relate to the enable or disable of the PS mode of the link of the first AP. The above one or more beacon intervals may include a specific beacon interval of a specific AP among the one or more APs based on one or more of the first information or the second information of the one or more APs including the first AP.

[0008] According to the present disclosure, a listening interval setting between an AP MLD and a non-AP MLD that supports access point (AP) power saving in a wireless LAN system, and a transmitting or receiving method and device based thereon may be provided.

[0009] The effects obtainable from the present disclosure are not limited to those mentioned above, and other unmentioned effects will be clearly understood by those skilled in the art to which the present disclosure belongs from the description below.

[0010] The accompanying drawings, which are included as part of the detailed description to aid in understanding the present disclosure, provide embodiments of the present disclosure and explain the technical features of the present disclosure together with the detailed description.

[0011] FIG. 1 illustrates a block diagram of a wireless communication device according to one embodiment of the present disclosure.

[0012] FIG. 2 is a drawing showing an exemplary structure of a wireless LAN system to which the present disclosure can be applied.

[0013] FIG. 3 is a diagram illustrating a link setup process to which the present disclosure can be applied.

[0014] FIG. 4 is a drawing illustrating a backoff process to which the present disclosure may be applied.

[0015] FIG. 5 is a diagram illustrating a CSMA / CA-based frame transmission operation to which the present disclosure may be applied.

[0016] FIG. 6 is a drawing for illustrating an example of a frame structure used in a wireless LAN system to which the present disclosure may be applied.

[0017] FIG. 7 is a drawing illustrating examples of PPDUs defined in the IEEE 802.11 standard to which the present disclosure may be applied.

[0018] FIG. 8 is a diagram illustrating an example of an MLD listen interval-based operation related to the present disclosure.

[0019] FIG. 9 is a drawing illustrating an additional example of an MLD listen interval-based operation related to the present disclosure.

[0020] FIG. 10 is a drawing for illustrating an example of a method performed in a non-AP STA according to the present disclosure.

[0021] FIG. 11 is a drawing for illustrating an example of a method performed in an AP according to the present disclosure.

[0022] 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 intended to describe exemplary embodiments of the present disclosure and is not intended to represent the only embodiment in which the present disclosure may be practiced. The following detailed description includes specific details to provide a complete understanding of the present disclosure. However, those skilled in the art will know that the present disclosure may be practiced without such specific details.

[0023] In some cases, to avoid obscuring the concept of the present disclosure, known structures and devices may be omitted or illustrated in the form of a block diagram focusing on the core functions of each structure and device.

[0024] In the present disclosure, when a component is described as being “connected,” “combined,” or “joined” with another component, this may include not only a direct connection but also an indirect connection in which another component exists between them. Furthermore, in the present disclosure, the terms “comprising” or “having” specify the presence of the mentioned features, steps, actions, elements, and / or components, but do not exclude the presence or addition of one or more other features, steps, actions, elements, components, and / or groups thereof.

[0025] In the present disclosure, terms such as "first," "second," etc. are used solely for the purpose of distinguishing one component from another and are not used to limit the components, nor do they limit the order or importance of the components unless specifically stated otherwise. Accordingly, within the scope of the present disclosure, a first component in one embodiment may be referred to as a second component in another embodiment, and likewise, a second component in one embodiment may be referred to as a first component in another embodiment.

[0026] The terms used in this disclosure are for the description of specific embodiments and are not intended to limit the claims. As used in the description of embodiments and in the appended claims, the singular form is intended to include the plural form unless the context clearly indicates otherwise. The term "and / or" as used in this disclosure may refer to any one of the related enumerated items, or refers to and includes any and all possible combinations of two or more of them. Additionally, the " / " between words in this disclosure has the same meaning as "and / or" unless otherwise noted.

[0027] The embodiments of the present disclosure may be applied to various wireless communication systems. For example, the embodiments of the present disclosure may be applied to wireless LAN systems. For example, the embodiments of the present disclosure may be applied to wireless LANs based on IEEE 802.11a / g / n / ac / ax / be standards. Furthermore, the embodiments of the present disclosure may be applied to wireless LANs based on newly proposed IEEE 802.11bn (or UHR) standards. Additionally, the embodiments of the present disclosure may be applied to wireless LANs based on next-generation standards following IEEE 802.11bn. Furthermore, the embodiments of the present disclosure may be applied to cellular wireless communication systems. For example, they may be applied to cellular wireless communication systems based on LTE (Long Term Evolution) series technologies and 5G NR (New Radio) series technologies of 3GPP (3rd Generation Partnership Project) standards.

[0028] The following describes the technical features to which the examples of the present disclosure may be applied.

[0029] FIG. 1 illustrates a block diagram of a wireless communication device according to one embodiment of the present disclosure.

[0030] The first device (100) and the second device (200) exemplified in FIG. 1 may be replaced with various terms such as terminal, wireless device, WTRU (Wireless Transmit Receive Unit), UE (User Equipment), MS (Mobile Station), UT (user terminal), MSS (Mobile Subscriber Station), MSS (Mobile Subscriber Unit), SS (Subscriber Station), AMS (Advanced Mobile Station), WT (Wireless terminal), or simply user. Additionally, the first device (100) and the second device (200) may be replaced with various terms such as access point (AP), base station (BS), fixed station, Node B, base transceiver system (BTS), network, artificial intelligence (AI) system, road side unit (RSU), repeater, router, relay, gateway, etc.

[0031] The device (100, 200) exemplified in FIG. 1 may be referred to as a station (STA). For example, the device (100, 200) exemplified in FIG. 1 may be referred to by various terms such as a transmitting device, a receiving device, a transmitting STA, or a receiving STA. For example, the STA (110, 200) may perform the role of an access point (AP) or a non-AP. That is, in the present disclosure, the STA (110, 200) may perform the functions of an AP and / or a non-AP. If the STA (110, 200) performs the AP function, it may simply be referred to as an AP, and if the STA (110, 200) performs the non-AP function, it may simply be referred to as a STA. Additionally, in the present disclosure, the AP may also be indicated as an AP STA.

[0032] Referring to FIG. 1, the first device (100) and the second device (200) can transmit and receive wireless signals through various wireless LAN technologies (e.g., IEEE 802.11 series). The first device (100) and the second device (200) may include interfaces for the medium access control (MAC) layer and the physical layer (PHY) that comply with the specifications of the IEEE 802.11 standard.

[0033] In addition, the first device (100) and the second device (200) may additionally support various communication standards other than wireless LAN technology (e.g., 3GPP LTE series, 5G NR series standards, etc.). In addition, the device of the present disclosure may be implemented as various devices such as mobile phones, vehicles, personal computers, AR (Augmented Reality) equipment, VR (Virtual Reality) equipment, etc. Furthermore, the STA of the present specification may 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), and IoT (Internet-of-Things).

[0034] The first device (100) includes one or more processors (102) and one or more memories (104), and may additionally include one or more transceivers (106) and / or one or more antennas (108). The processor (102) controls the memory (104) and / or transceivers (106) and may be configured to implement the descriptions, functions, procedures, proposals, methods and / or sequences of operation disclosed in this disclosure. For example, the processor (102) may process information within the memory (104) to generate a first information / signal and then transmit a wireless signal containing the first information / signal through the transceiver (106). Additionally, the processor (102) may receive a wireless signal containing a second information / signal through the transceiver (106) and then store information obtained from the signal processing of the second information / signal in the memory (104). Memory (104) may be connected to the processor (102) and may store various information related to the operation of the processor (102). For example, memory (104) may store software code including instructions for performing some or all of the processes controlled by the processor (102) or for performing the descriptions, functions, procedures, proposals, methods, and / or sequences of operation disclosed in this disclosure. Here, the processor (102) and memory (104) may be part of a communication modem / circuit / chip designed to implement wireless LAN technology (e.g., IEEE 802.11 series). A transceiver (106) may be connected to the processor (102) and may transmit and / or receive wireless signals through one or more antennas (108). The transceiver (106) may include a transmitter and / or receiver. The transceiver (106) may be combined with an RF (Radio Frequency) unit. In the present disclosure, the device may refer to a communication modem / circuit / chip.

[0035] The second device (200) includes one or more processors (202) and one or more memories (204), and may additionally include one or more transceivers (206) and / or one or more antennas (208). The processor (202) controls the memory (204) and / or transceivers (206) and may be configured to implement the descriptions, functions, procedures, proposals, methods and / or sequences of operation disclosed in this disclosure. For example, the processor (202) may process information within the memory (204) to generate a third information / signal and then transmit a wireless signal containing the third information / signal through the transceiver (206). Additionally, the processor (202) may receive a wireless signal containing a fourth information / signal through the transceiver (206) and then store information obtained from the signal processing of the fourth information / signal in the memory (204). The memory (204) may be connected to the processor (202) and may store various information related to the operation of the processor (202). For example, the memory (204) may store software code containing instructions for performing some or all of the processes controlled by the processor (202) or for performing the descriptions, functions, procedures, proposals, methods, and / or sequences of operation disclosed in this 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., IEEE 802.11 series). The transceiver (206) may be connected to the processor (202) and may transmit and / or receive wireless signals through one or more antennas (208). The transceiver (206) may include a transmitter and / or receiver. The transceiver (206) may be used in combination with an RF unit. In the present disclosure, the device may refer to a communication modem / circuit / chip.

[0036] Hereinafter, hardware elements of the device (100, 200) will be described in more detail. Although not limited thereto, one or more protocol layers may be implemented by one or more processors (102, 202). For example, one or more processors (102, 202) may implement one or more layers (e.g., functional layers such as PHY, MAC). One or more processors (102, 202) may generate one or more Protocol Data Units (PDUs) and / or Service Data Units (SDUs) according to the descriptions, functions, procedures, proposals, methods, and / or flowcharts of operation disclosed in this disclosure. One or more processors (102, 202) may generate messages, control information, data, or information according to the descriptions, functions, procedures, proposals, methods, and / or flowcharts of operation disclosed in this disclosure. One or more processors (102, 202) may generate a signal (e.g., a baseband signal) including a PDU, SDU, message, control information, data, or information according to the functions, procedures, proposals, and / or methods disclosed in this disclosure and provide it to one or more transceivers (106, 206). One or more processors (102, 202) may receive a signal (e.g., a baseband signal) from one or more transceivers (106, 206) and may obtain a PDU, SDU, message, control information, data, or information according to the descriptions, functions, procedures, proposals, methods, and / or flowcharts disclosed in this disclosure.

[0037] One or more processors (102, 202) may be referred to as a controller, microcontroller, microprocessor, or microcomputer. One or more processors (102, 202) may be implemented by hardware, firmware, software, or a combination thereof. For example, one or more Application Specific Integrated Circuits (ASICs), one or more Digital Signal Processors (DSPs), one or more Digital Signal Processing Devices (DSPDs), one or more Programmable Logic Devices (PLDs), or one or more Field Programmable Gate Arrays (FPGAs) may be included in one or more processors (102, 202). The descriptions, functions, procedures, proposals, methods, and / or flowcharts disclosed in this disclosure may be implemented using firmware or software, and the firmware or software may be implemented to include modules, procedures, functions, etc. Firmware or software configured to perform the descriptions, functions, procedures, proposals, methods, and / or operation sequences disclosed in this disclosure may be included in one or more processors (102, 202) or stored in one or more memories (104, 204) and driven by one or more processors (102, 202). The descriptions, functions, procedures, proposals, methods, and / or operation sequences disclosed in this disclosure may be implemented using firmware or software in the form of code, instructions, and / or sets of instructions.

[0038] One or more memories (104, 204) may be connected to one or more processors (102, 202) and may store various forms of data, signals, messages, information, programs, codes, instructions, and / or commands. One or more memories (104, 204) may be composed of ROM, RAM, EPROM, flash memory, hard drive, registers, cache memory, computer read storage media, and / or combinations thereof. One or more memories (104, 204) may be located inside and / or outside of one or more processors (102, 202). Additionally, one or more memories (104, 204) may be connected to one or more processors (102, 202) through various technologies such as wired or wireless connections.

[0039] One or more transceivers (106, 206) may transmit user data, control information, wireless signals / channels, etc., as mentioned in the methods and / or operation flowcharts, etc., of the present disclosure to one or more other devices. One or more transceivers (106, 206) may receive user data, control information, wireless signals / channels, etc., as mentioned in the descriptions, functions, procedures, proposals, methods and / or operation flowcharts, etc., 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 may transmit and receive wireless signals. For example, one or more processors (102, 202) may control one or more transceivers (106, 206) to transmit user data, control information, or wireless signals to one or more other devices. Additionally, one or more processors (102, 202) may control one or more transceivers (106, 206) to receive user data, control information, or wireless signals from one or more other devices. Additionally, one or more transceivers (106, 206) may be connected to one or more antennas (108, 208), and one or more transceivers (106, 206) may be configured to transmit and receive user data, control information, wireless signals / channels, etc., as described in the descriptions, functions, procedures, proposals, methods, and / or flowcharts of operation disclosed in this disclosure through one or more antennas (108, 208). In this disclosure, one or more antennas may be a plurality of physical antennas or a plurality of logical antennas (e.g., antenna ports). One or more transceivers (106, 206) can convert the received wireless signal / channel, etc. from an RF band signal to a baseband signal in order to process the received user data, control information, wireless signal / channel, etc. using one or more processors (102, 202).One or more transceivers (106, 206) can convert user data, control information, wireless signals / channels, etc. processed using one or more processors (102, 202) from baseband signals to RF band signals. To this end, one or more transceivers (106, 206) may include (analog) oscillators and / or filters.

[0040] For example, one of the STAs (100, 200) may perform the intended operation of an AP, and the other of the STAs (100, 200) may perform the intended operation of a non-AP STA. For example, the transceiver (106, 206) of FIG. 1 may perform the operation of transmitting and receiving signals (e.g., packets or PPDU (Physical Layer Protocol Data Unit) according to IEEE 802.11a / b / g / n / ac / ax / be / bn, etc.). Additionally, the operation of generating transmission and reception signals or performing data processing or calculations in advance for transmission and reception signals by various STAs in the present disclosure may be performed by the processor (102, 202) of FIG. 1. For example, an example of an operation to generate a transmission and reception signal or to perform data processing or operations in advance for a transmission and reception signal may include: 1) an operation to determine / acquire / configure / operate / decode / encode bit information of fields (SIG (signal), STF (short training field), LTF (long training field), Data, etc.) included in the PPDU; 2) an operation to determine / configure / acquire time resources or frequency resources (e.g., subcarrier resources) used for fields (SIG, STF, LTF, Data, etc.) included in the PPDU; 3) an operation to determine / configure / acquire specific sequences (e.g., pilot sequence, STF / LTF sequence, extra sequence applied to SIG) used for fields (SIG, STF, LTF, Data, etc.) included in the PPDU; 4) power control operations and / or power saving operations applied to the STA; and 5) operations related to determining / acquiring / configuring / operating / decoding / encoding of an ACK signal. In addition, in the following example, various information (e.g., information related to fields, subfields, control fields, parameters, power, etc.) used by various STAs for determining / acquiring / configuring / calculating / decoding / encoding of transmission and reception signals can be stored in the memory (104, 204) of FIG. 1.

[0041] In the following, the downlink (DL) refers to a link for communication from an AP STA to a non-AP STA, and downlink PPDUs, packets, signals, etc., can be transmitted and received through the downlink. In downlink communication, the transmitter may be part of the AP STA, and the receiver may be part of the non-AP STA. The uplink (UL) refers to a link for communication from a non-AP STA to an AP STA, and uplink PPDUs, packets, signals, etc., can be transmitted and received through the uplink. In uplink communication, the transmitter may be part of the non-AP STA, and the receiver may be part of the AP STA.

[0042] FIG. 2 is a drawing showing an exemplary structure of a wireless LAN system to which the present disclosure can be applied.

[0043] The structure of a wireless LAN system can be composed of multiple components. Through the interaction of multiple components, a wireless LAN that supports STA mobility transparent to the upper layer can be provided. A Basic Service Set (BSS) corresponds to the basic building block of a wireless LAN. Figure 2 exemplarily illustrates the existence of two BSSs (BSS1 and BSS2) and the inclusion of two STAs as members of each BSS (STA1 and STA2 are included in BSS1, and STA3 and STA4 are included in BSS2). In Figure 2, the ellipse representing the BSS can also be understood as representing the coverage area where the STAs included in the corresponding BSS maintain communication. This area can be referred to as a Basic Service Area (BSA). If a STA moves outside the BSA, it becomes unable to communicate directly with other STAs within that BSA.

[0044] Excluding the DS illustrated in Fig. 2, the most basic type of BSS in a wireless LAN is the Independent BSS (IBSS). For example, an IBSS can have a minimal form consisting of only two STAs. For instance, assuming other components are omitted, a BSS1 composed of only STA1 and STA2, or a BSS2 composed of only STA3 and STA4, can each be considered a representative example of an IBSS. Such a configuration is possible when the STAs can communicate directly without an AP. Furthermore, this type of wireless LAN is not configured through pre-planning but can be configured when a LAN is needed, and this can be referred to as an ad-hoc network. Since an IBSS does not include an AP, there is no centralized management entity. In other words, in an IBSS, STAs are managed in a distributed manner. In IBSS, all STAs can be mobile STAs, and since connections to distributed systems (DS) are not allowed, they form a self-contained network.

[0045] The membership of an STA in a BSS can be dynamically changed by the STA being turned on or off, or by the STA entering or leaving the BSS area. To become a member of a BSS, an STA can join the BSS using a synchronization process. To access all services of the BSS infrastructure, an STA must be associated with the BSS. This association can be configured dynamically and may include the use of a Distribution System Service (DSS).

[0046] In a wireless LAN, the direct STA-to-STA distance may be limited by PHY performance. In some cases, this distance limit may be sufficient, but in others, communication between STAs over longer distances may be required. To support extended coverage, a distributed system (DS) may be configured.

[0047] DS refers to a structure in which BSSs are interconnected. Specifically, as shown in FIG. 2, a BSS may exist as a component in an extended form of a network composed of multiple BSSs. DS is a logical concept and can be specified by the characteristics of the Distributed System Medium (DSM). In this regard, the Wireless Medium (WM) and the DSM can be logically distinguished. Each logical medium is used for a different purpose and is utilized by different components. These media are not limited to being identical or different. The flexibility of the wireless LAN structure (DS structure or other network structure) can be explained by the fact that multiple media are logically distinct in this way. That is, the wireless LAN structure can be implemented in various ways, and the corresponding wireless LAN structure can be specified independently by the physical characteristics of each implementation.

[0048] DS can support mobile devices by providing seamless integration of multiple BSSs and providing logical services necessary for handling addresses to destinations. Additionally, DS may include a component called a portal that acts as a bridge for connecting the wireless LAN with another network (e.g., IEEE 802.X).

[0049] An AP refers to an entity that enables access to a DS via a WM for combined non-AP STAs and also possesses the functionality of an STA. Data movement between a BSS and a DS can be performed through the AP. For example, STA2 and STA3 shown in FIG. 2 possess the functionality of an STA and provide the ability for combined non-AP STAs (STA1 and STA4) to access a DS. Furthermore, since all APs fundamentally correspond to STAs, all APs are addressable entities. The address used by the AP for communication on the WM and the address used by the AP for communication on the DSM do not necessarily have to be the same. A BSS composed of an AP and one or more STAs can be referred to as an infrastructure BSS.

[0050] Data transmitted from one of the STA(s) coupled to the AP to the STA address of the AP can always be received at an uncontrolled port and processed by an IEEE 802.1X port access entity. Additionally, if the controlled port is authenticated, the transmitted data (or frame) can be forwarded to the DS.

[0051] In addition to the structure of the aforementioned DS, an Extended Service Set (ESS) may be configured to provide wider coverage.

[0052] An ESS refers to a network of arbitrary size and complexity composed of DSs and BSSs. An ESS can correspond to a set of BSSs connected to a single DS. However, an ESS does not contain a DS. An ESS network is characterized by appearing as an IBSS at the Logical Link Control (LLC) layer. STAs included in an ESS can communicate with each other, and mobile STAs can move from one BSS to another (within the same ESS) transparently to the LLC. APs included in a single ESS can have the same Service Set Identification (SSID). The SSID is distinct from the BSSID, which is the identifier for the BSS.

[0053] In wireless LAN systems, no assumptions are made regarding the relative physical locations of BSSs, and all of the following forms are possible. BSSs may partially overlap, which is a form commonly used to provide continuous coverage. Additionally, BSSs may not be physically connected, and logically, there is no limit to the distance between BSSs. Furthermore, BSSs may be located in the same physical location, which can be used to provide redundancy. Also, one (or more) IBSS or ESS networks may physically exist in the same space as one (or more) ESS networks. This may apply to ESS network forms such as when an ad-hoc network operates at a location where an ESS network exists, when wireless networks that physically overlap are configured by different organizations, or when two or more different access and security policies are required at the same location.

[0054] FIG. 3 is a diagram illustrating a link setup process to which the present disclosure can be applied.

[0055] In order for an STA to set up a link and transmit and receive data on a network, it must first discover the network, perform authentication, establish an association, and go through authentication procedures for security. The link setup process can also be referred to as the session initiation process or the session setup process. Additionally, the processes of discovery, authentication, association, and security setup in the link setup process can be collectively referred to as the association process.

[0056] In step S310, the STA may perform a network discovery operation. The network discovery operation may include the STA's scanning operation. That is, in order for the STA to access a network, it must find a network it can join. Before joining a wireless network, the STA must identify a compatible network, and the process of identifying networks existing in a specific area is called scanning.

[0057] Scanning methods include active scanning and passive scanning. Figure 3 illustrates a network discovery operation that includes an active scanning process as an example. In active scanning, the STA performing the scanning moves between channels to search for nearby APs, transmits a probe request frame, and waits for a response. The responder transmits a probe response frame as a response to the probe request frame to the STA that transmitted the probe request frame. Here, the responder may be the STA that last transmitted a beacon frame from the BSS of the channel being scanned. In a BSS, the AP becomes the responder because it transmits the beacon frame; however, in an IBSS, the responder is not constant because STAs within the IBSS take turns transmitting the beacon frame. For example, an STA that transmits a probe request frame on channel 1 and receives a probe response frame on channel 1 can store BSS-related information included in the received probe response frame and move to the next channel (e.g., channel 2) to perform scanning in the same way (i.e., transmit and receive probe request / response on channel 2).

[0058] Although not illustrated in FIG. 3, the scanning operation may be performed using a passive scanning method. In passive scanning, the STA performing the scanning waits for a beacon frame while switching between channels. A beacon frame is one of the management frames defined in IEEE 802.11, which is periodically transmitted to announce the presence of a wireless network and to allow the scanning STA to find the wireless network and join it. In a BSS, the AP performs the role of periodically transmitting beacon frames, and in an IBSS, the STAs within the IBSS take turns transmitting beacon frames. When the scanning STA receives a beacon frame, it stores the information about the BSS included in the beacon frame and records the beacon frame information in each channel while moving to another channel. The STA that receives the beacon frame stores the BSS-related information included in the received beacon frame, moves to the next channel, and can perform scanning in the next channel in the same way. When comparing active scanning and passive scanning, active scanning has the advantage of lower delay and power consumption than passive scanning.

[0059] After the STA discovers the network, an authentication process may be performed in step S320. This authentication process may be referred to as the first authentication process to clearly distinguish it from the security setup operation in step S340 described later.

[0060] The authentication process involves the STA sending an authentication request frame to the AP, and the AP sending an authentication response frame to the STA in response. The authentication frame used in the authentication request / response corresponds to a management frame.

[0061] The authentication frame may include information regarding the authentication algorithm number, authentication transaction sequence number, status code, challenge text, Robust Security Network (RSN), Finite Cyclic Group, etc. These are some examples of information that may be included in the authentication request / response frame, and they may be replaced with other information or additional information may be included.

[0062] The STA can send an authentication request frame to the AP. Based on the information contained in the received authentication request frame, the AP can determine whether to allow authentication for the STA. The AP can provide the result of the authentication process to the STA through an authentication response frame.

[0063] After the STA is successfully authenticated, the association process can be performed in step S330. The association process includes the STA transmitting an association request frame to the AP, and in response, the AP transmitting an association response frame to the STA.

[0064] For example, the association request frame may include information regarding various capabilities, beacon listen interval, service set identifier (SSID), supported rates, supported channels, RSN, mobility domain, supported operating classes, Traffic Indication Map Broadcast request, interworking service capabilities, etc. For example, the association response frame may include information regarding various capabilities, status code, Association ID (AID), supported rates, Enhanced Distributed Channel Access (EDCA) parameter set, Received Channel Power Indicator (RCPI), Received Signal to Noise Indicator (RSNI), mobility domain, timeout interval (e.g., association comeback time), overlapping BSS scan parameters, TIM broadcast response, Quality of Service (QoS) map, etc. These are some examples of information that may be included in a combined request / response frame, and may be replaced with other information or additional information may be included.

[0065] After the STA is successfully joined to the network, a security setup process can be performed in step S340. The security setup process in step S340 may be described as an authentication process through RSNA (Robust Security Network Association) requests / responses, and the authentication process in step S320 may be referred to as the first authentication process, and the security setup process in step S340 may simply be referred to as the authentication process.

[0066] The security setup process of step S340 may include, for example, a private key setup process through a 4-way handshake via an EAPOL (Extensible Authentication Protocol over LAN) frame. Additionally, the security setup process may be performed according to a security method not defined in the IEEE 802.11 standard.

[0067] FIG. 4 is a drawing illustrating a backoff process to which the present disclosure may be applied.

[0068] In wireless LAN systems, the basic access mechanism for MAC (Medium Access Control) is the CSMA / CA (Carrier Sense Multiple Access with Collision Avoidance) mechanism. The CSMA / CA mechanism is also known as the Distributed Coordination Function (DCF) of IEEE 802.11 MAC, and it basically employs a "listen before talk" access mechanism. According to this type of access mechanism, the AP and / or STA may perform Clear Channel Assessment (CCA) to sense the wireless channel or medium for a predetermined time interval (e.g., DIFS (DCF Inter-Frame Space)) before starting transmission. If the sensing result determines that the medium is in an idle status, it starts transmitting a frame through that medium. On the other hand, if the medium is detected to be occupied or busy, the AP and / or STA may not start its own transmission but wait by setting a delay period for medium access (e.g., a random backoff period) before attempting to transmit a frame. By applying a random backoff period, multiple STAs are expected to attempt to transmit frames after waiting for different periods of time, thereby minimizing collisions.

[0069] In addition, the IEEE 802.11 MAC protocol provides a Hybrid Coordination Function (HCF). The HCF is based on the aforementioned Point Coordination Function (PCF). The PCF is a polling-based synchronous access method that periodically polls to ensure all receiving APs and / or STAs can receive data frames. Furthermore, the HCF includes Enhanced Distributed Channel Access (EDCA) and Controlled Channel Access (HCCA). EDCA is a contention-based access method for a provider to offer data frames to multiple users, while HCCA uses a non-contention-based channel access method utilizing a polling mechanism. Additionally, the HCF includes a media access mechanism to improve the Quality of Service (QoS) of the wireless LAN and can transmit QoS data during both the Contention Period (CP) and the Contention-Free Period (CFP).

[0070] Referring to FIG. 4, the operation based on the random backoff period is described. When a medium in an occupied / busy state changes to an idle state, multiple STAs may attempt to transmit data (or frames). As a measure to minimize collisions, each STA may select a random backoff count and attempt transmission after waiting for the corresponding slot time. The random backoff count has a pseudo-random integer value and can be determined as one of the values ​​in the range from 0 to CW. Here, CW is the Contention Window parameter value. The CW parameter is given an initial value of CWmin, but in the case of transmission failure (e.g., failure to receive an ACK for a transmitted frame), it may take a value twice that amount. When the CW parameter value becomes CWmax, data transmission may be attempted while maintaining the CWmax value until data transmission is successful; if data transmission is successful, it is reset to the CWmin value. The values ​​of CW, CWmin, and CWmax are 2 n It is desirable to set it to -1 (n=0, 1, 2, ...).

[0071] When the random backoff process begins, the STA continues to monitor the media while counting down the backoff slots according to the determined backoff count value. When the media is monitored as occupied, it stops the countdown and waits, and when the media becomes idle, it resumes the remaining countdown.

[0072] In the example of Fig. 4, when a packet to be transmitted arrives at the MAC of STA3, STA3 confirms that the medium is idle for DIFS and can immediately transmit the frame. The remaining STAs monitor whether the medium is occupied or busy and wait. Meanwhile, data to be transmitted may also arise from each of STA1, STA2, and STA5, and each STA can perform a countdown of the backoff slot according to a random backoff count value selected by each after waiting for DIFS when the medium is monitored to be idle. Assume the case where STA2 selects the smallest backoff count value and STA1 selects the largest backoff count value. That is, this exemplifies a case where, at the point when STA2 finishes the backoff count and starts transmitting the frame, the remaining backoff time of STA5 is shorter than the remaining backoff time of STA1. STA1 and STA5 pause the countdown briefly and wait while STA2 occupies the medium. When STA2's possession ends and the medium becomes idle again, STA1 and STA5 wait for DIFS and then resume the paused backoff count. That is, they can start transmitting a frame after counting down the remaining backoff slots corresponding to the remaining backoff time. Since STA5's remaining backoff time was shorter than STA1's, STA5 starts transmitting the frame. While STA2 is occupying the medium, data to be transmitted may also be generated by STA4. From STA4's perspective, when the medium becomes idle, it waits for DIFS, performs a countdown based on a random backoff count value selected by itself, and can start transmitting a frame. The example in Figure 4 illustrates a case where STA5's remaining backoff time happens to match STA4's random backoff count value; in this case, a collision may occur between STA4 and STA5. If a collision occurs, neither STA4 nor STA5 receives an ACK, resulting in a failure to transmit data.In this case, STA4 and STA5 can double the CW value, select a random backoff count value, and perform a countdown. STA1 waits while the medium is occupied due to transmission by STA4 and STA5, and when the medium becomes idle, it waits for DIFS, and then can start transmitting frames after the remaining backoff time has passed.

[0073] As shown in the example in Fig. 4, a data frame is a frame used for transmitting data that is forwarded to an upper layer, and can be transmitted after a backoff performed after the elapsed time of DIFS from when the medium becomes idle. Additionally, a management frame is a frame used for exchanging management information that is not forwarded to an upper layer, and is transmitted after a backoff performed after the elapsed time of an IFS such as DIFS or PIFS (Point coordination function IFS). Subtypes of management frames include Beacon, Association request / response, re-association request / response, probe request / response, and authentication request / response. A control frame is a frame used to control access to the medium. Subtype frames of control frames include RTS (Request-To-Send), CTS (Clear-To-Send), ACK (Acknowledgment), PS-Poll (Power Save-Poll), Block ACK (BlockAck), Block ACK Request (BlockACKReq), NDP Announcement (null data packet announcement), and Trigger. If a control frame is not an acknowledgment frame of a previous frame, it is transmitted after a backoff performed after the elapsed DIFS; if it is an acknowledgment frame of a previous frame, it is transmitted after the elapsed SIFS (short IFS) without a backoff. The type and subtype of a frame can be identified by the type field and subtype field within the Frame Control (FC) field.

[0074] A QoS (Quality of Service) STA can transmit a frame after backoff, which is performed after the passage of the AIFS (arbitration IFS) for the access category (AC) to which the frame belongs, i.e., AIFS[i] (where i is a value determined by the AC). Here, the frame for which AIFS[i] can be used can be a data frame or a management frame, and can also be a control frame rather than a response frame.

[0075] FIG. 5 is a diagram illustrating a CSMA / CA-based frame transmission operation to which the present disclosure may be applied.

[0076] As previously mentioned, the CSMA / CA mechanism includes virtual carrier sensing in addition to physical carrier sensing, where the STA directly senses the medium. Virtual carrier sensing is intended to mitigate problems that may occur in medium access, such as the hidden node problem. For virtual carrier sensing, the STA's MAC can utilize the Network Allocation Vector (NAV). The NAV is a value that indicates to other STAs the time remaining until the medium becomes available, provided that the STA currently using or authorized to use the medium is using it. Therefore, the value set as the NAV corresponds to the period during which the medium is scheduled to be used by the STA transmitting the frame, and the STA receiving the NAV value is prohibited from accessing the medium during that period. For example, the NAV can be set based on the value of the "duration" field in the frame's MAC header.

[0077] In the example of FIG. 5, it is assumed that STA1 intends to transmit data to STA2, and STA3 is located in a position where it can overhear part or all of the frames transmitted and received between STA1 and STA2.

[0078] In order to reduce the possibility of collisions between multiple STAs in a CSMA / CA-based frame transmission operation, a mechanism utilizing RTS / CTS frames may be applied. In the example of FIG. 5, while STA1 is transmitting, the medium may be determined to be idle based on the carrier sensing result of STA3. That is, STA1 may be a hidden node to STA3. Alternatively, in the example of FIG. 5, while STA2 is transmitting, the medium may be determined to be idle based on the carrier sensing result of STA3. That is, STA2 may be a hidden node to STA3. By exchanging RTS / CTS frames before performing data transmission and reception between STA1 and STA2, it is possible to prevent a STA outside the transmission range of either STA1 or STA2, or a STA outside the carrier sensing range for transmission from STA1 or STA3, from attempting to occupy the channel during data transmission and reception between STA1 and STA2.

[0079] Specifically, STA1 can determine whether the channel is in use through carrier sensing. In terms of physical carrier sensing, STA1 can determine the channel occupancy idle state based on the energy magnitude or signal correlation detected in the channel. Additionally, in terms of virtual carrier sensing, STA1 can determine the channel occupancy state using a NAV (network allocation vector) timer.

[0080] If the channel is idle during DIFS, STA1 can send an RTS frame to STA2 after performing backoff. If STA2 receives the RTS frame, it can send a CTS frame to STA1 as a response to the RTS frame after SIFS.

[0081] If STA3 cannot overhear a CTS frame from STA2 but can overhear an RTS frame from STA1, STA3 can set a NAV timer for the duration of subsequently transmitted frames (e.g., SIFS + CTS frame + SIFS + data frame + SIFS + ACK frame) using the duration information included in the RTS frame. Alternatively, if STA3 cannot overhear an RTS frame from STA1 but can overhear a CTS frame from STA2, STA3 can set a NAV timer for the duration of subsequently transmitted frames (e.g., SIFS + data frame + SIFS + ACK frame) using the duration information included in the CTS frame. That is, if STA3 can overhear one or more of the RTS or CTS frames from one or more of STA1 or STA2, it can set a NAV accordingly. If STA3 receives a new frame before the NAV timer expires, it can update the NAV timer using the duration information contained in the new frame. STA3 does not attempt channel access until the NAV timer expires.

[0082] If STA1 receives a CTS frame from STA2, it may transmit a data frame to STA2 after SIFS from the time the reception of the CTS frame is completed. If STA2 successfully receives the data frame, it may transmit an ACK frame to STA1 as an acknowledgment to the data frame after SIFS. STA3 may determine whether the channel is in use through carrier sensing when the NAV timer expires. If STA3 determines that the channel is not in use by another terminal during DIFS from the time the NAV timer expires, it may attempt channel access after a contention window (CW) based on random backoff has passed.

[0083] FIG. 6 is a drawing for illustrating an example of a frame structure used in a wireless LAN system to which the present disclosure may be applied.

[0084] Based on instructions or primitives (meaning a set of instructions or parameters) from the MAC layer, the PHY layer can prepare the MPDU (MAC PDU) to be transmitted. For example, upon receiving an instruction from the MAC layer requesting the start of transmission, the PHY layer switches to transmit mode and can construct the information provided by the MAC layer (e.g., data) into a frame for transmission. Additionally, if the PHY layer detects a valid preamble of a received frame, it monitors the preamble header and sends an instruction to the MAC layer indicating the start of reception.

[0085] As such, information transmission and reception in wireless LAN systems are carried out in the form of frames, and for this purpose, the Physical Layer Protocol Data Unit (PPDU) format is defined.

[0086] A basic PPDU may include a Short Training Field (STF), a Long Training Field (LTF), a Signal (SIGNAL) field, and a Data field. The most basic (e.g., the non-HT (High Throughput)) PPDU format illustrated in FIG. 7 may consist only of Legacy-STF (Legacy-STF), Legacy-LTF (Legacy-LTF), Legacy-SIG (Legacy-SIG) fields and a Data field. In addition, 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 details will be described later with reference to FIG. 7.

[0087] STF is a signal for signal detection, AGC (Automatic Gain Control), diversity selection, and precise time synchronization, while LTF is a signal for channel estimation and frequency error estimation. STF and LTF can be considered signals for synchronization and channel estimation in the OFDM physical layer.

[0088] The SIG field may contain various information related to the transmission and reception of the PPDU. For example, the L-SIG field consists of 24 bits and may include a 4-bit Rate field, a 1-bit Reserved bit, a 12-bit Length field, a 1-bit Parity field, and a 6-bit Tail field. The RATE field may contain information regarding the modulation and coding rates 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 as a multiple of 3. For example, for HE PPDUs, the value of the Length field may be determined as a multiple of 3 + 1 or a multiple of 3 + 2.

[0089] The data field may include a SERVICE field, a PSDU (Physical layer Service Data Unit), and PPDU TAIL bits, and may also include padding bits if necessary. Some bits of the SERVICE field may be used for synchronization of the descrambler at the receiver. The PSDU corresponds to a MAC PDU defined at the MAC layer and may contain data generated or used by the upper layer. The PPDU TAIL bits may be used to return the encoder to a 0 state. Padding bits may be used to adjust the length of the data field to a predetermined unit.

[0090] A MAC PDU is defined according to various MAC frame formats, and a basic MAC frame consists of a MAC header, a frame body, and a Frame Check Sequence (FCS). A MAC frame is composed of a MAC PDU and can be transmitted or received through the PSDU of the data portion in the PPDU format.

[0091] The MAC header includes a Frame Control field, a Duration / ID field, an Address field, etc. The Frame Control field may contain control information necessary for transmitting or receiving frames. The Duration / ID field may be set as the time for transmitting the corresponding frame. Address subfields may indicate the frame's receiver address, transmitter address, destination address, and source address, and some address subfields may be omitted. Specific details regarding each subfield of the MAC header, including Sequence Control, QoS Control, and HT Control subfields, can be found in the IEEE 802.11 standard document.

[0092] The Null-Data PPDU (NDP) format refers to a PPDU format that does not include a data field. In other words, NDP is a frame format that includes the PPDU preamble (i.e., L-STF, L-LTF, L-SIG fields, and additionally, non-legacy SIG, non-legacy STF, and non-legacy LTF if present) from a standard PPDU format, but excludes the remaining parts (i.e., the data field).

[0093] FIG. 7 is a drawing illustrating examples of PPDUs defined in the IEEE 802.11 standard to which the present disclosure may be applied.

[0094] Various forms of PPDU have been used in standards such as IEEE 802.11a / g / n / ac / ax. The basic PPDU format (IEEE 802.11a / g) includes L-LTF, L-STF, L-SIG, and Data fields. The basic PPDU format may also be referred to as the non-HT PPDU format (Fig. 7(a)).

[0095] The HT PPDU format (IEEE 802.11n) additionally includes HT-SIG, HT-STF, and HT-LFT(s) fields in addition to the basic PPDU format. The HT PPDU format illustrated in FIG. 7(b) may be referred to as the HT-mixed format. Additionally, an HT-greenfield format PPDU may be defined, which corresponds to a format consisting of HT-GF-STF, HT-LTF1, HT-SIG, one or more HT-LTFs, and a Data field, without including L-STF, L-LTF, and L-SIG (not shown).

[0096] An example of the VHT PPDU format (IEEE 802.11ac) includes the VHT SIG-A, VHT-STF, VHT-LTF, and VHT-SIG-B fields in addition to the basic PPDU format (Fig. 7(c)).

[0097] An example of the HE PPDU format (IEEE 802.11ax) includes the RL-SIG (Repeated L-SIG), HE-SIG-A, HE-SIG-B, HE-STF, HE-LTF(s), and PE (Packet Extension) fields in addition to the basic PPDU format (Fig. 7(d)). Depending on the specific examples of the HE PPDU format, some fields may be excluded or their lengths may vary. For example, the HE-SIG-B field is included in the HE PPDU format for multiple users (MU), but is not included in the HE PPDU format for single users (SU). Additionally, the HE trigger-based (TB) PPDU format does not include HE-SIG-B, and the length of the HE-STF field may vary to 8 µs. The HE ER (Extended Range) SU PPDU format does not include the HE-SIG-B field, and the length of the HE-SIG-A field may vary to 16 µs. For example, RL-SIG can be configured identically to L-SIG. Based on the presence of RL-SIG, the receiving STA can determine that the received PPDU is a HE PPDU or the EHT PPDU described later.

[0098] 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 RL-SIG following L-SIG, but it may include U (universal)-SIG, EHT-SIG, EHT-STF, and EHT-LTF following RL-SIG.

[0099] The EHT MU PPDU of FIG. 7(e) corresponds to a PPDU that carries one or more data (or PSDU) for one or more users. That is, the EHT MU PPDU can be used for both SU transmission and MU transmission. For example, the EHT MU PPDU can correspond to a PPDU for one receiving STA or multiple receiving STAs.

[0100] The EHT-SIG is omitted in the EHT TB PPDU of FIG. 7(f) 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.

[0101] The L-STF, L-LTF, L-SIG, RL-SIG, U-SIG (Universal SIGNAL), and EHT-SIG fields can be encoded and modulated so that demodulation and decoding can be attempted even on legacy STAs, and 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 can 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) to obtain the information contained in the corresponding fields, and mapped based on a defined subcarrier frequency interval (e.g., 78.125 kHz). These can be referred to as EHT modulated fields.

[0102] Similarly, in the HE PPDU format, the L-STF, L-LTF, L-SIG, RL-SIG, HE-SIG-A, and HE-SIG-B fields can be referred to as pre-HE modulation fields, and the HE-STF, HE-LTF, Data, and PE fields can be referred to as HE modulation fields. 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 modulation fields, and the VHT STF, VHT-LTF, VHT-SIG-B, and Data fields can be referred to as VHT modulation fields.

[0103] The U-SIG included in the EHT PPDU format of FIG. 7 can be constructed based on, for example, two symbols (e.g., two consecutive OFDM symbols). Each symbol for the U-SIG (e.g., OFDM symbol) can have a duration of 4 µs, and the U-SIG can have a total duration of 8 µs. Each symbol of the U-SIG can be used to transmit 26 bits of information. For example, each symbol of the U-SIG can be transmitted and received based on 52 data tones and 4 pilot tones.

[0104] U-SIGs can be configured in 20 MHz units. For example, if an 80 MHz PPDU is configured, the same U-SIG can be duplicated in 20 MHz units. That is, four identical U-SIGs can be included within an 80 MHz PPDU. If 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.

[0105] For example, A number of uncoded bits may be transmitted through U-SIG, and the first symbol of U-SIG (e.g., U-SIG-1 symbol) transmits the first X bits of the total A bit information, and the second symbol of U-SIG (e.g., U-SIG-2 symbol) transmits the remaining Y bits of the total A bit information. The A bit information (e.g., 52 uncoded bits) may include a CRC field (e.g., a field of 4 bits) and a tail field (e.g., a field of 6 bits). The tail field may be used to terminate the trellis of the convolution decoder and may be set to, for example, 0.

[0106] A bit information transmitted by U-SIG can be divided into version-independent bits and version-dependent bits. For example, U-SIG may be included in a new PPDU format not shown in FIG. 7 (e.g., UHR PPDU format), and in the format of the U-SIG field included in the EHT PPDU format and the format of the U-SIG field included in the UHR PPDU format, the version-independent bits may be the same, and some or all of the version-dependent bits may be different.

[0107] 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 to both U-SIG-1 and U-SIG-2 symbols. The version-independent bits and version-dependent bits may be referred to by various names, such as the first control bit and the second control bit.

[0108] For example, the version-independent bits of U-SIG may include a 3-bit physical layer version identifier (PHY version identifier), and this information may indicate the PHY version of the transmitted / 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 relates to UL communication, and the second value of the UL / DL flag field relates to DL communication. The version-independent bits of U-SIG may include information regarding the length of the TXOP (transmission opportunity) and information regarding the BSS color ID.

[0109] For example, the version-dependent bits of U-SIG may contain information that directly or indirectly indicates the type of PPDU (e.g., SU PPDU, MU PPDU, TB PPDU, etc.).

[0110] Information necessary for PPDU transmission and reception may be included in the U-SIG. For example, the U-SIG may further include information regarding bandwidth, information regarding MCS techniques applied to non-legacy SIGs (e.g., EHT-SIG or UHR-SIG, etc.), information indicating whether DCM (dual carrier modulation) techniques (e.g., techniques to achieve an effect similar to frequency diversity by reusing the same signal on two subcarriers) are applied to non-legacy SIGs, information regarding the number of symbols used for non-legacy SIGs, and information regarding whether non-legacy SIGs are generated across the entire band.

[0111] Some of the information required for PPDU transmission and reception may be included in U-SIG and / or non-legacy SIGs (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 non-legacy LTF and cyclic prefix (CP) length, information regarding guard interval (GI) applied to non-legacy LTF, information regarding preamble puncturing applicable to PPDU, information regarding resource unit (RU) allocation, etc., may be included only in U-SIG, may be included only in non-legacy SIG, or may be indicated by a combination of information included in U-SIG and information included in non-legacy SIG.

[0112] Preamble puncturing may refer to the transmission of a PPDU in which a signal is not present in one or more frequency units within the PPDU bandwidth. For example, the size of the frequency unit (or the resolution of 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 larger.

[0113] 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. A non-legacy SIG may be transmitted through at least one symbol, and one symbol may have a length of 4 µs. Information regarding the number of symbols used for EHT-SIG may be included in the previous SIG (e.g., HE-SIG-A, U-SIG, etc.).

[0114] Non-legacy SIGs, such as HE-SIG-B and EHT-SIG, may include common fields and user-specific fields. Common fields and user-specific fields may be coded individually.

[0115] In some cases, the common field may be omitted. For example, in a compression mode where non-OFDMA (orthogonal frequency multiple access) is applied, the common field may be omitted, and multiple STAs may receive PPDUs (e.g., the data field of the PPDU) over the same frequency band. In a non-compression mode where OFDMA is applied, multiple users may receive PPDUs (e.g., the data field of the PPDU) over different frequency bands.

[0116] The number of user-specific fields can be determined based on the number of users. A single user block field can contain up to two user fields. Each user field may be related to MU-MIMO allocation or non-MU-MIMO allocation.

[0117] 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 set to 000000. The common field may include RU allocation information. The RU allocation information may include information regarding the location of the RU to which a plurality of users (i.e., a plurality of receiving STAs) are allocated.

[0118] An RU may include multiple subcarriers (or tones). An RU may be used when transmitting signals to multiple STAs based on the OFDMA technique. Additionally, an RU may be defined when transmitting signals to a single STA. Resources may be allocated on an RU basis for non-legacy STF, non-legacy LTF, and Data fields.

[0119] Applicable RU sizes can be defined according to the PPDU bandwidth. RUs may be defined identically or differently for the applicable PPDU format (e.g., HE PPDU, EHT PPDU, UHR PPDU, etc.). For example, in the case of an 80 MHz PPDU, the RU placement for HE PPDU and EHT PPDU may differ. The applicable RU sizes, number of RUs, RU locations, DC (direct current) subcarrier locations and numbers, null subcarrier locations and numbers, and guard subcarrier locations and numbers for each PPDU bandwidth can be referred to as a tone-plan. For example, a tone-plan for a wide bandwidth may be defined as a multiple repetition of a tone-plan for a low bandwidth.

[0120] RUs of various sizes can be defined as 26-ton RUs, 52-ton RUs, 106-ton RUs, 242-ton RUs, 484-ton RUs, 996-ton RUs, 2x996-ton RUs, 4x996-ton RUs, etc. An MRU (multiple RU) is distinguished from multiple individual RUs and corresponds to a group of subcarriers composed of multiple RUs. For example, one MRU can be defined as 52+26-tons, 106+26-tons, 484+242-tons, 996+484-tons, 996+484+242-tons, 2x996+484-tons, 3x996-tons, or 3x996+484-tons. In addition, multiple RUs constituting a single MRU may be continuous or non-continuous in the frequency domain.

[0121] The specific size of the RU may be reduced or expanded. Accordingly, the specific size of each RU (i.e., the number of corresponding tones) in this disclosure is not limited and is exemplary. Additionally, within a given bandwidth (e.g., 20, 40, 80, 160, 320 MHz, ...) in this disclosure, the number of RUs may vary depending on the RU size.

[0122] The names of the respective fields in the PPDU formats of FIG. 7 are exemplary and the scope of the present disclosure is not limited by such names. Furthermore, the examples of the present disclosure may be applied not only to the PPDU formats exemplified in FIG. 7, but also to new PPDU formats based on the PPDU formats of FIG. 7 in which some fields are excluded and / or some fields are added.

[0123] Multi-link operation

[0124] The following describes the multi-link (ML) operations supported by the STA according to the present disclosure.

[0125] The STA (AP STA and / or non-AP STA) described in this disclosure may support multi-link (ML) communication. ML communication may refer to communication that supports multiple links. The links involved in ML communication may include channels (e.g., 20 / 40 / 80 / 160 / 240 / 320 MHz channels) in the frequency band (e.g., 2.4 GHz band, 5 GHz band, 6 GHz band, etc.) in which the STA operates. The multiple links used for ML communication may be configured in various ways. For example, the multiple links supported by a single STA for ML communication may belong to the same frequency band or to different frequency bands. Additionally, each link may correspond to a frequency unit of a predetermined size (e.g., channel, subchannel, RU, etc.). Furthermore, some or all of the multiple links may be frequency units of the same size or frequency units of different sizes.

[0126] When a single STA supports multiple links, the transmitting and receiving devices supporting each link can operate as a single logical STA. That is, an MLD refers to a device that, as a logical entity, has one or more affiliated STAs and a single MAC Service Access Point (SAP) for a single MAC data service and logical link control (LLC). A non-AP MLD refers to an MLD where each STA affiliated with the MLD is a non-AP STA. A multi-radio non-AP MLD refers to a non-AP MLD that supports the reception or exchange of frames on one or more links at a time. An AP MLD refers to an MLD where each STA affiliated with the MLD is an AP STA.

[0127] Multi-Link Operation (MLO) can enable a non-AP MLD to discover, authenticate, associate, and set up multiple links for an AP MLD. Based on the supported capabilities exchanged during the association process, each link can enable channel access and frame exchange between the non-AP MLD and the AP MLD. An STA affiliated with an MLD can select and manage its capabilities and operation parameters independently of other STA(s) affiliated with the same MLD.

[0128] Through a 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: whether simultaneous transmit and receive (STR) operations that allow simultaneous transmission and receive on multiple links supported by the MLD, or non-simultaneous transmit and receive (NSTR) operations that do not allow simultaneous transmission and receive; information regarding the number / upper limit of UL / DL links; information regarding the location / band / resource of UL / DL links; information regarding frame types available or preferred on at least one UL / DL link (e.g., management, control, data, etc.); information regarding ACK policies available or preferred on at least one UL / DL link; or information regarding traffic identifiers (TID) available on at least one UL / DL link.

[0129] An AP MLD (e.g., an NSTR mobile AP MLD) may set one of the multiple links as the primary link. The AP MLD may perform beacon frames, probe response frames, and group-addressed data frames only on the primary link. The remaining other links of the multiple links may be non-primary links. An AP MLD operating on a non-primary link may operate so as not to transmit beacon frames or probe response frames. Additionally, a non-AP MLD may perform frame exchange during authentication, (re)association, and 4-way handshake only on the primary link.

[0130] A setup link is defined as enabled if at least one traffic identifier (TID) is mapped to the link through the multi-link setup process, and may be defined as disabled if no TID is mapped to the link. A TID must always be mapped to at least one setup link unless admission control is used. By default, TIDs are mapped to all setup links, so all setup links can be enabled.

[0131] When a link is activated, it may be used for frame switching depending on the power state of the non-AP STA operating on that link. Only MSDUs or A-MSDUs with TIDs mapped to the activated link may be transmitted on that link. Management frames and control frames may only be transmitted on the activated link.

[0132] If a link is disabled, it may not be used for frame exchange, including management frames for both DL and UL.

[0133] During the multi-link setup process, the activation / deactivation of each link can be directed through TID-to-Link mapping. TID-to-Link mapping can be performed in default mapping mode or / and negotiation mapping mode.

[0134] One of the STAs belonging to the MLD may provide information about one or more links other than the link where it is located for multi-link discovery (e.g., obtaining information about multiple links including the link on a single link) or multi-link setup (e.g., associating simultaneously on multiple links through the exchange of association request / response frames on a single link). To provide this information, a multi-link (ML) element may be defined.

[0135] AP and AP MLD Aging Function

[0136] The AP aging function or AP MLD aging function can be defined so that the bufferable unit (BU) buffered in the listen interval field of a (re)combination request frame is not discarded after a period shorter than that indicated by the STA. That is, according to the AP aging function or AP MLD aging function, the data buffered for the STA (e.g., DL BU) can be discarded after the STA's listen interval has passed.

[0137] These aging functions can be implemented in various ways. Additionally, aging functions may be applied independently of or in addition to other causes for MSDU disposal in MAC entities (e.g., data lifetime-related behaviors).

[0138] Listen Interval Field

[0139] In the case of general (or non-MLD) coupling, the listen interval field may be used to inform the AP how often a STA in power-save mode wakes up to listen for beacon frames. It may also be used to inform the AP of the duration required for a STA with non-TIM mode enabled to transmit one or more frames addressed to the coupled AP. This listen interval field may have a value in units of beacon intervals or short beacon intervals.

[0140] In the case of (re)joining for MLD joining, the listen interval field may be used to inform the AP MLD how often one or more STAs belonging to the non-AP MLD wake up and listen for beacon frames when all STAs belonging to the non-AP MLD are in power-saving mode. This listen interval field may have a value in units of the maximum value among multiple beacon intervals corresponding to multiple links that the non-AP MLD intends to set up in the (re)joining request frame.

[0141] The length of the listen interval field can be 2 octets. A value of 0 for the listen interval field may be used by a STA that does not belong to an MLD, or when all STAs belonging to a non-AP MLD do not enter power saving mode.

[0142] In the case of a general (or non-MLD) (re)joining, the AP can use the listen interval to determine the lifetime of the frame buffered for the STA.

[0143] In the case of (re)joining for MLD joining, the AP can use the listen interval to determine the lifetime of the frame buffered for non-AP MLD.

[0144] Action for MLD listen intervals

[0145] During a multi-link (re)setup, the value included in the listen interval field of a (re)join request frame transmitted by a non-AP STA belonging to a non-AP MLD to an AP belonging to an AP MLD is requested at the MLD level. The value of the listen interval field may have a value based on the maximum value among multiple beacon intervals corresponding to the multiple links that the non-AP MLD intends to set up in the (re)join request frame. The AP belonging to the AP MLD may refuse the (re)setup because the listen interval requested by the non-AP MLD is too large. After a successful multi-link (re)setup, the AP MLD may use the listen interval to determine the lifetime of the frames buffered for the non-AP MLD. For example, the value of the listen interval field may be defined as not changing after a successful multi-link (re)setup.

[0146] AP MLDs may delete buffered BUs for various reasons, including the use of aging functions and the availability of buffers (e.g., AP MLD aging functions, etc.). Here, aging functions may be based on a listen interval specified by a non-AP MLD in a (re)join request frame or a WNM sleep interval specified by a non-AP MLD in a WNM (wireless network management) sleep mode request frame.

[0147] If all non-AP STAs operating on enabled links belonging to a non-AP MLD are in power saving mode, one or more of these non-AP STAs need to wake up and listen for one or more beacon frames. These one or more beacon frames are scheduled within an interval of the same duration as the listen interval indicated by the non-AP MLD in the (re)join request frame, and this may start from the last target beacon transmission time (TBTT) when the corresponding non-AP STA or another non-AP STA belonging to the non-AP MLD was in the awake state.

[0148] FIG. 8 is a diagram illustrating an example of an MLD listen interval-based operation related to the present disclosure.

[0149] In the example of Fig. 8, it is assumed that the AP MLD has three affiliated APs, namely, AP 1 operating on Link 1, AP 2 operating on Link 2, and AP 3 operating on Link 3. It is assumed that the beacon intervals of Link 1, Link 2, and Link 3 are 250 ms, 200 ms, and 70 ms, respectively.

[0150] A non-AP STA 1 belonging to a non-AP MLD can transmit a join request frame to an AP 1 belonging to an AP MLD. Non-AP STA 1 can request setup for three links (i.e., Link 1 between AP 1 and non-AP STA 1, Link 2 between AP 2 and non-AP STA 2, and Link 3 between AP 3 and non-AP STA 3). The value of the listen interval field included in the join request frame can be set to 1, and that value corresponds to a value in units of the maximum beacon interval (i.e., 250 ms). Therefore, the listen interval value requested by the non-AP MLD is 250 ms.

[0151] AP 1, which belongs to the AP MLD, can accept three links for the ML setup (i.e., Link 1 between AP 1 and non-AP STA 1, Link 2 between AP 2 and non-AP STA 2, and Link 3 between AP 3 and non-AP STA 3) by sending a combined response frame to non-AP STA 1, which belongs to the non-AP MLD.

[0152] After a successful ML setup, non-AP STA 2 and non-AP STA 3 can enter power saving mode. After that, non-AP STA 1 can enter power saving mode. For example, it can signal a PM set to a value of 1.

[0153] In this case, the AP MLD can buffer the DL BU(s) for the non-AP MLD for at least 250 ms. For example, at time T1, non-AP STA 1 receives a beacon frame on Link 1, and non-AP STAs belonging to the non-AP MLD are required to wake up before time T2 (e.g., T2 = T1 + 250 ms) to receive one or more beacon frames. For example, non-AP STA 1 may receive a second beacon frame on Link 1 (at T1 + 250 ms), or non-AP STA 2 may receive a second beacon frame on Link 2 (at T1 + 200 ms), or non-AP STA 3 may receive a fourth beacon frame on Link 3 (at T1 + 280 ms). In the example of Fig. 8, for the sake of simplicity, the case where the first beacon frame on all links is aligned at the same time is shown as an example, but in reality, the first TBTT on all links may not be aligned.

[0154] FIG. 9 is a drawing illustrating an additional example of an MLD listen interval-based operation related to the present disclosure.

[0155] In the example of Fig. 9, it is assumed that the AP MLD has three affiliated APs, namely AP 1 operating on Link 1, AP 2 operating on Link 2, and AP 3 operating on Link 3. It is assumed that the beacon intervals of Link 1, Link 2, and Link 3 are 250 ms, 200 ms, and 70 ms, respectively.

[0156] A non-AP STA 2 belonging to a non-AP MLD can transmit a join request frame to an AP 2 belonging to an AP MLD. Non-AP STA 2 can request setup for three links (i.e., Link 1 between AP 1 and non-AP STA 1, Link 2 between AP 2 and non-AP STA 2, and Link 3 between AP 3 and non-AP STA 3). The value of the listen interval field included in the join request frame can be set to 1, and that value corresponds to a value in units of the maximum beacon interval (i.e., 250 ms). Therefore, the listen interval value requested by the non-AP MLD is 250 ms.

[0157] AP 2, which belongs to the AP MLD, can accept two links for the ML setup (i.e., Link 2 between AP 2 and non-AP STA 2, and Link 3 between AP 3 and non-AP STA 3) by sending a combined response frame to non-AP STA 1, which belongs to the non-AP MLD.

[0158] Here, the listen interval requested by the non-AP MLD is still 250 ms, and this does not change depending on the link accepted in the ML setup procedure.

[0159] After a successful ML setup, non-AP STA 3 can enter power saving mode. After that, non-AP STA 2 can enter power saving mode. For example, it can signal a PM set to a value of 1.

[0160] In this case, the AP MLD can buffer the DL BU(s) for the non-AP MLD for at least 250 ms. For example, at time T1, non-AP STA 2 receives a beacon frame on Link 2, and one of the non-AP STA 2 or non-AP STA 3 belonging to the non-AP MLD is required to wake up before time T2 (e.g., T2 = T1 + 250 ms) to receive one or more beacon frames. For example, non-AP STA 2 may receive a second beacon frame on Link 2 (at T1 + 200 ms), or non-AP STA 3 may receive a fourth beacon frame on Link 3 (at T1 + 280 ms). For simplicity, the example in Fig. 9 illustrates the case where the first beacon frames on all links are aligned at the same time, but in reality, the first TBTTs on all links may not be aligned.

[0161] As described above, the STA can transmit to the AP by setting the listen interval field within the (re)join request frame to a value corresponding to the listen interval length desired / requested by the STA. The length of the listen interval requested by the STA can be determined by the STA based on information such as TIM, DTIM (delivery TIM), and beacon interval included in the beacon frame or probe response frame received by the STA from the AP. If the AP cannot accept the listen interval requested by the STA, it may send a (re)assemble response frame to the STA containing a status code set to a value indicating rejection and the reason therefor (e.g., status code value 51 (Denied_LISTEN_INTERVAL_Too_LARGE)). If the AP can accept the listen interval requested by the STA, the AP may send a (re)assemble response frame to the STA with the status code value set to a value indicating acceptance.

[0162] Based on the listen interval set through this process, the AP buffers data (e.g., beacon frames, DL BU, etc.) to the STA, and when the STA becomes awake after the listen interval from the doze / sleep state and transmits a PS-Poll frame to the AP, the AP can respond by transmitting the buffered data / frame to the STA. If the AP does not receive a PS-Poll frame from the STA even after the listen interval and cannot determine whether the STA in the doze / sleep state has become awake, or if it is determined that the STA has not become awake, the AP can delete / discard the buffered data / frame for the STA after a predetermined time.

[0163] The listen interval on the MLD can be set through negotiation involving the exchange of an ML (re)setup request and an ML (re)setup response. The ML (re)setup request and the ML (re)setup response can be performed through the transmission and reception of a (re)join request frame and a (re)join response frame, respectively. The STA can set the value of the listen interval field included in the (re)join request frame based on the longest value among the beacon intervals of multiple APs within the AP MLD (i.e., using the maximum value among the beacon intervals as a unit, for example, as an integer multiple of the maximum value). For example, APs belonging to the AP MLD may have different beacon interval values, and the listen interval at the MLD level may be set based on one of them (e.g., the maximum) beacon interval (i.e., as an integer multiple of one beacon interval).

[0164] AP MLD-based listen interval supporting Power Saving (PS)

[0165] An AP can generally remain in an active or awake state to provide high throughput and fast service to associated STAs. For example, a non-AP STA can switch between sleep / doze and active / awake states to reduce battery consumption, and various power-saving (PS) modes can be applied for this purpose.

[0166] APs can perform frame switching using the highest possible bandwidth and a large number of spatial streams. Additionally, APs are typically fixed in a single location and receive constant power to provide such services. Consequently, due to the high power consumption of APs, issues such as increased network maintenance costs and reduced battery life for battery-operated APs (e.g., mobile APs) are arising.

[0167] In addition, considering multi-link operation and multi-AP cooperative networks, the number of STAs operating on the links of multi-link devices (MLDs) can increase further. Consequently, the power consumption of the AP can increase further.

[0168] A novel method of the present disclosure for reducing the power consumption of an AP is described below. The scope of the present disclosure is not limited thereto, and the examples of the present disclosure may be applied to all STAs without distinguishing between AP and non-AP.

[0169] It can be assumed that an AP affiliated with an AP MLD supports AP Power Saving (PS), and that the beacon interval of that AP is the longest among the beacon intervals of multiple APs belonging to that AP MLD. According to the existing listen interval operation for AP MLDs, the AP MLD and non-AP MLDs can determine and apply the listen interval based on the beacon interval of the corresponding AP. For example, the existing operation can determine the listen interval based on the longest beacon interval within the AP MLD without distinguishing whether the AP supports or enables AP PS operation.

[0170] APs within an AP MLD that support / enable AP PS can set a long beacon interval to reduce the number of times they switch between active and awake states to transmit beacon frames, taking into account the time spent in sleep / doze states. If the listen interval is determined based on the long beacon interval of an AP that supports / enables AP PS, it may be difficult for APs within an AP MLD that do not support / enable AP PS to store / maintain buffered DL data frames during the long listen interval.

[0171] Accordingly, in determining the listen interval of a non-AP MLD in the present disclosure, the remaining beacon interval(s) may be considered, excluding the beacon interval of an AP that supports / enables AP PS (e.g., based on the longest value among the remaining beacon interval(s). To this end, various examples of the present disclosure are described below for a non-AP STA belonging to a non-AP MLD to determine whether the AP(s) belonging to the AP MLD support / enable AP PS, and to determine / apply a listen interval based on the beacon interval(s) based thereon.

[0172] FIG. 10 is a drawing for illustrating an example of a method performed in a non-AP STA according to the present disclosure.

[0173] In the example of Fig. 10, non-AP STAs belong to non-AP MLDs, and one or more APs may belong to AP MLDs.

[0174] In step S1010, a non-AP STA may receive one or more of the first information or the second information from one or more APs.

[0175] In some examples, the first information may relate to the support of PS mode of one or more links of the AP MLD, and the second information may relate to the enable or disable of PS mode of one or more links of the AP MLD.

[0176] In some examples, the first information and / or the second information may be provided to a non-AP STA via a beacon frame from each of one or more APs.

[0177] In some examples, the first information may be provided to a non-AP STA through a multi-link setup process (e.g., through an ML setup response frame, (re)combination response frame, etc.). After the multi-link setup process, the second information may be provided to a non-AP STA through a control frame, a management frame, and / or a data frame.

[0178] In step S1020, the non-AP STA can determine the listen interval based on one or more beacon intervals associated with one or more APs.

[0179] For example, a non-AP STA can be determined based on the maximum value among one or more beacon intervals (e.g., equal to the maximum value of the beacon interval).

[0180] In some examples, one or more beacon intervals that form the basis for determining the listen interval may be determined based on first information and / or second information of one or more APs received in step S1010.

[0181] For example, one or more beacon intervals may not include the beacon intervals of all APs / links of the AP MLD, but may exclude the beacon interval(s) of some AP(s) and include the beacon interval(s) of specific AP(s). Whether the beacon intervals of which APs / links are excluded or included may be determined based on the first information and / or the second information.

[0182] In some examples, one or more beacon intervals that form the basis for determining the listen interval may not include the beacon interval of the AP / link where the support of PS mode is indicated by the first information.

[0183] In some examples, one or more beacon intervals that form the basis for determining the listen interval may include a beacon interval of an AP / link where the PS mode is indicated as not supported by the first information.

[0184] In some examples, one or more beacon intervals that form the basis for determining the listen interval may not include the beacon interval of the AP / link where the enable of the PS mode is indicated by the second information.

[0185] In some examples, one or more beacon intervals that form the basis for determining the listen interval may include the beacon interval of the AP / link where the disable of the PS mode is indicated by the second information.

[0186] In some examples, one or more beacon intervals that form the basis for determining the listen interval may not include a beacon interval of an AP / link in which the support of PS mode is indicated by the first information and the enable of PS mode is indicated by the second information.

[0187] In some examples, one or more beacon intervals that form the basis for determining the listen interval may include a beacon interval of an AP / link in which the support of PS mode is indicated by the first information, but the disable of PS mode is indicated by the second information.

[0188] In some examples, where one or more beacon intervals forming the basis for determining the listen interval include a beacon interval of an AP / link where PS mode is not supported by the first information, the one or more beacon intervals forming the basis for determining the listen interval may be determined without relying on (or regardless of) the second information regarding the said AP / link (e.g., the AP / link where PS mode is not supported by the first information).

[0189] Although not illustrated in the example of FIG. 10, in some examples, when one or more beacon intervals forming the basis for determining the listen interval do not include the beacon interval of the AP / link for which the enable of the PS mode is indicated by the second information, a request for an update of the listen interval of a value based on such one or more beacon intervals may be sent from the non-AP STA to the AP MLD. In this case, the updated listen interval may be applied by the non-AP STA based on the receipt of a response from the AP MLD indicating permission for the request.

[0190] The method described in the example of FIG. 10 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 (e.g., a non-AP STA belonging to a non-AP MLD) may be configured to receive first information and / or second information from one or more second devices (200) (e.g., one or more APs belonging to an AP MLD) via one or more transceivers (106), and to determine a listen interval based on one or more beacon intervals based on the first information and / or second information (e.g., including the beacon interval of a specific AP / link or excluding the beacon interval of another AP / link). Furthermore, one or more memories (104) of the first device (100) may store instructions for performing the method described in the example of FIG. 10 or the examples described below when executed by one or more processors (102).

[0191] FIG. 11 is a drawing for illustrating an example of a method performed in a first AP according to the present disclosure.

[0192] In the example of Fig. 11, the first AP belongs to the AP MLD together with other AP(s), and the non-AP STA may belong to the non-AP MLD.

[0193] In step S1110, the first AP may transmit the first information and / or the second information to a non-AP STA.

[0194] In step S1120, the first AP can perform transmission / reception based on a listen interval determined by a non-AP STA based on one or more beacon intervals associated with one or more APs (e.g., including the first AP) belonging to the AP MLD.

[0195] In the example of FIG. 11, the specific description of the first information, the second information, and one or more beacon intervals that form the basis for determining the listen interval is the same as in the example of FIG. 10, so the redundant description is omitted.

[0196] The method described in the example of FIG. 11 can 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 (e.g., a first AP belonging to an AP MLD) can be configured to transmit first information and / or second information to the first device (100) (e.g., a non-AP STA belonging to a non-AP MLD) through one or more transceivers (206), and to perform transmission / reception with the non-AP STA through one or more transceivers (206) according to a listen interval determined among one or more beacon intervals of one or more APs based on the first information and / or second information of one or more APs (e.g., including the first AP). Furthermore, one or more memories (204) of the second device (200) may store instructions for performing the method described in the example of FIG. 11 or the examples described below when executed by one or more processors (202).

[0197] The non-AP STA of FIG. 10 corresponds to the receiving STA of the first information and / or the second information, and the first AP of FIG. 11 may correspond to the transmitting STA of the first information and / or the second information.

[0198] For example, before configuring the PPDU, the transmitting STA may generate / determine information regarding the AP PS of the APs belonging to the AP MLD (information indicating whether the AP PS is supported and / or enabled) and / or information indicating whether the value(s) of the beacon interval of specific AP(s) belonging to the AP MLD should be included or excluded on the basis of the listen interval determination. The transmitting STA may generate a MAC frame containing this information and generate a PPDU containing it and transmit it to the receiving STA.

[0199] For example, when a receiving STA receives a PPDU from a transmitting STA, it can parse a MAC frame obtained through PHY decoding of the data field of the PPDU and obtain from the parsed MAC frame information related to the AP PS of the AP belonging to the AP MLD (information indicating whether the AP PS is supported and / or enabled) and / or information indicating whether to include or exclude the beacon interval value(s) of the specific AP(s) belonging to the AP MLD on the basis for determining the listen interval. Based on this decoded data, when determining / applying the listen interval value at the MLD level between the AP MLD and the non-AP MLD, the receiving STA can determine / apply the listen interval by excluding the beacon interval(s) of the specific AP(s) based on the information provided by the transmitting STA.

[0200] For example, according to the examples of the present disclosure, when (re)combining between an AP MLD and a non-AP MLD or performing a multi-link (ML) setup, the beacon interval value of an AP that supports / enables AP PS among the APs belonging to the AP MLD may be excluded from the determination / setting of the listen interval. To this end, a method is required for the non-AP MLD to recognize which AP(s) belonging to the AP MLD support / enable AP PS. Specific examples of how the non-AP MLD recognizes which AP(s) among the APs belonging to the AP MLD support / enable (or are enabled) AP PS are described below.

[0201] The first information described in this disclosure (e.g., information regarding support for AP PS mode) and / or the second information (e.g., information regarding enable / disable of AP PS mode) may be transmitted through various management frames or control frames (e.g., (re)combination request / response, ML setup request / response, beacon frame, or new management / control frame), or various elements / fields within various control / management frames (e.g., UHR MAC capability field, or new elements / fields).

[0202] In the present disclosure, the method of indicating whether any AP(s) within an AP MLD support / enable AP PS may include explicit indication and implicit indication methods.

[0203] The examples of FIGS. 10 and 11 may correspond to some of the various examples of the present disclosure. Hereinafter, various examples of the present disclosure including the examples of FIGS. 10 and 11 will be described in more detail.

[0204] Example 1

[0205] This embodiment relates to an AP power saving support (sub)field. For example, the AP power saving support (sub)field may be a new (sub)field.

[0206] First, I will explain the power saving modes of various APs.

[0207] An AP that supports a scheduled power save mode can periodically perform a transition operation between the awake state and the doze state. For example, the AP can schedule periods for periodically transitioning from the sleep state to the awake state based on a target wake time (TWT) method and / or a link disablement / enablement method. The AP can notify the combined STA(s) of information regarding the scheduled periods. The AP can maintain the awake state within the notified scheduled periods, but can maintain the sleep state during periods excluding the scheduled periods.

[0208] An AP that supports unscheduled power save mode is a mode that transitions from sleep state to awake state only when there is a request from a STA. For example, if a STA transmits a request signal related to power save mode (e.g., a polling signal) to the AP, the AP may transition from doze state to awake state in response to the request signal, but is not limited thereto.

[0209] An AP supporting dynamic power save mode can transition from the doze state to the awake state upon receiving an initial control frame (ICF) from a STA, and can transmit an initial control response (ICR) frame to the STA in the awake state. For example, the AP can transition from the doze state, where data transmission and reception are impossible, to the awake state, and / or operate in a listening mode capable of receiving data from the combined STA(s). Additionally, dynamic power save mode can be operated in conjunction with other power save (PS) modes and active modes. For example, the AP can enter the listening mode / state based on the dynamic PS mode from the awake state of the active mode or scheduled / unscheduled PS mode, thereby reducing power consumption.

[0210] According to one example of the present disclosure, if the AP supports a scheduled power saving mode and / or an unscheduled power saving mode, the value of the AP power saving support (sub)field may be set to a first value (e.g., 1). Otherwise (e.g., if it does not support a scheduled power saving mode, or if it does not support an unscheduled power saving mode, or if it does not support both a scheduled power saving mode and an unscheduled power saving mode), the value of the corresponding (sub)field may be set to a second value (e.g., 0).

[0211] For example, a non-AP MLD can determine whether AP power saving is supported based on the value of the corresponding (sub)field, and exclude the AP's beacon interval when setting the listen interval if AP power saving is supported.

[0212] Additionally or alternatively, if the AP supports dynamic (AP) power saving, which can be defined as AP power saving, the corresponding (sub)field may be set to a value (e.g., 1) indicating that AP power saving is supported. In this case, the non-AP MLD may not exclude the beacon interval of the AP when setting the listen interval based on the value of the corresponding (sub)field. This is because, since an AP supporting dynamic power saving mode can be switched from a doze state to an awake state by an ICF from the STA, the beacon interval of an AP supporting dynamic power saving mode can be considered by the STA when determining the listen interval (unlike scheduled / unscheduled AP power saving modes).

[0213] As an additional example, we will explain the case where an AP power saving enable / disable (sub)field exists.

[0214] In addition to the AP power saving support (sub)field having a value (e.g., 1) indicating that AP power saving is supported, if the value of the AP power saving enable / disable (sub)field is a value (e.g., 1) indicating that AP power saving is enabled, the non-AP MLD can exclude the beacon interval of the corresponding AP when setting the listen interval.

[0215] If the AP Power Saving Support (sub)field has a value (e.g., 1) indicating that AP Power Saving is supported, and the AP Power Saving Enable / Disable (sub)field has a value (e.g., 0) indicating that AP Power Saving is disabled, the non-AP MLD may or may not exclude the beacon interval of the corresponding AP when setting the listen interval. For example, if the beacon interval of an AP that supports AP Power Saving is greater than or equal to a specific TU value, the beacon interval of that AP may be excluded when setting the listen interval. Or, if the beacon interval of an AP that supports AP Power Saving is less than or equal to a specific TU value, the beacon interval of that AP may be included when setting the listen interval.

[0216] Alternatively, if the AP power saving support (sub)field has a value (e.g., 1) indicating that AP power saving is supported, and the AP power saving enable / disable (sub)field has a value (e.g., 0) indicating that AP power saving is disabled, the non-AP MLD may not exclude the beacon interval of the corresponding AP (regardless of the TU value criteria) when setting the listen interval.

[0217] Example 2

[0218] This embodiment relates to a scheduled AP power saving support (sub)field. For example, the scheduled AP power saving support (sub)field may be a new (sub)field.

[0219] If the AP supports a scheduled power saving mode, which is one of the AP power saving modes, the corresponding (sub)field can be set to a first value (e.g., 1). Otherwise, the corresponding (sub)field can be set to a second value (e.g., 0).

[0220] The non-AP MLD determines whether the scheduled AP power saving mode is supported based on the relevant information, and if an AP supports the scheduled AP power saving mode, it can exclude the beacon interval of that AP when setting the listen interval.

[0221] As an additional example, we will explain the case where a scheduled AP power saving enable / disable (sub)field exists.

[0222] In the case where the Scheduled AP Power Saving Support (sub)field has a value (e.g., 1) indicating that the Scheduled AP Power Saving Support (sub)field supports the Scheduled AP Power Saving mode, and the value of the Scheduled AP Power Saving Enable / Disable (sub)field is a value (e.g., 1) indicating that the Scheduled AP Power Saving mode is enabled, the non-AP MLD can exclude the beacon interval of the corresponding AP when setting the listen interval.

[0223] If the Scheduled AP Power Saving Support (sub)field has a value (e.g., 1) indicating that the Scheduled AP Power Saving Support (sub)field supports the Scheduled AP Power Saving mode, and the value of the Scheduled AP Power Saving Enable / Disable (sub)field is a value (e.g., 0) indicating that the Scheduled AP Power Saving mode is disabled, the non-AP MLD may or may not exclude the beacon interval of the corresponding AP when setting the listen interval. For example, if the beacon interval of the AP supporting the Scheduled AP Power Saving mode is greater than or equal to a specific TU value, the beacon interval of the corresponding AP may be excluded when setting the listen interval. Or, if the beacon interval of the AP supporting the Scheduled AP Power Saving mode is less than or equal to a specific TU value, the beacon interval of the corresponding AP may be included when setting the listen interval.

[0224] Alternatively, if the Scheduled AP Power Saving Support (sub)field has a value (e.g., 1) indicating that the Scheduled AP Power Saving Support (sub)field supports the Scheduled AP Power Saving mode, and the value of the Scheduled AP Power Saving Enable / Disable (sub)field is a value (e.g., 0) indicating that the Scheduled AP Power Saving mode is disabled, the non-AP MLD may not exclude the beacon interval of the corresponding AP (regardless of the TU value criteria) when setting the listen interval.

[0225] Example 3

[0226] This embodiment relates to an unscheduled AP power saving support (sub)field. For example, the unscheduled AP power saving support (sub)field may be a new (sub)field.

[0227] If the AP supports an unscheduled power saving mode, which is one of the AP power saving modes, the corresponding (sub)field can be set to a first value (e.g., 1). Otherwise, the corresponding (sub)field can be set to a second value (e.g., 0).

[0228] Based on this information, the non-AP MLD determines whether an unscheduled AP power saving mode is supported, and if an AP supports an unscheduled AP power saving mode, the beacon interval of that AP can be excluded when setting the listen interval.

[0229] As an additional example, we will explain the case where an unscheduled AP power saving enable / disable (sub)field exists.

[0230] In the case where the non-scheduled AP power saving support (sub)field has a value (e.g., 1) indicating that the non-scheduled AP power saving mode is supported, and the value of the non-scheduled AP power saving enable / disable (sub)field is a value (e.g., 1) indicating that the non-scheduled AP power saving mode is enabled, the non-AP MLD can exclude the beacon interval of the corresponding AP when setting the listen interval.

[0231] If the Unscheduled AP Power Saving Support (sub)field has a value (e.g., 1) indicating that the Unscheduled AP Power Saving mode is supported, and the Unscheduled AP Power Saving Enable / Disable (sub)field has a value (e.g., 0) indicating that the Unscheduled AP Power Saving mode is disabled, the non-AP MLD may or may not exclude the beacon interval of the corresponding AP when setting the listen interval. For example, if the beacon interval of an AP supporting the Unscheduled AP Power Saving mode is greater than or equal to a specific TU value, the beacon interval of that AP may be excluded when setting the listen interval. Or, if the beacon interval of an AP supporting the Unscheduled AP Power Saving mode is less than or equal to a specific TU value, the beacon interval of that AP may be included when setting the listen interval.

[0232] Or, if the unscheduled AP power saving support (sub)field has a value (e.g., 1) indicating that the unscheduled AP power saving mode is supported, and the value of the unscheduled AP power saving enable / disable (sub)field is a value (e.g., 0) indicating that the unscheduled AP power saving mode is disabled, the non-AP MLD may not exclude the beacon interval of the corresponding AP (regardless of the TU value criteria) when setting the listen interval.

[0233] Example 4

[0234] This embodiment relates to the AP power saving enable / disable (sub)field. For example, the AP power saving enable / disable (sub)field may be a new (sub)field.

[0235] The AP power saving enable / disable (sub)field can be set to a first value (e.g., 1) when the AP power saving operation is enabled, and can be set to a second value (e.g., 0) when the AP power saving operation is disabled, when the operation that can be defined as AP power saving is supported by the AP.

[0236] Based on the information, the non-AP MLD can determine whether the AP power saving operation is enabled or disabled, and if the AP power saving operation of a certain AP is enabled (or has a value of 1), the beacon interval of that AP can be excluded when setting the listen interval.

[0237] If the value of the corresponding (sub)field is disabled (or a value of 0) for AP power saving behavior, the non-AP MLD may or may not exclude the beacon interval of the corresponding AP when setting the listen interval. For example, if the beacon interval of an AP with disabled AP power saving behavior is greater than or equal to a specific TU value, the beacon interval of that AP may be excluded when setting the listen interval. Or, if the beacon interval of an AP with disabled AP power saving behavior is less than or equal to a specific TU value, the beacon interval of that AP may be included when setting the listen interval.

[0238] Alternatively, if the value of the corresponding (sub)field is disabled (or 0 value) for AP power saving operation, the non-AP MLD may not exclude the beacon interval of the corresponding AP (regardless of the TU value criteria) when setting the listen interval.

[0239] The AP Power Saving Enable / Disable (sub)field may be defined separately from the AP Power Saving Support (sub)field, or the AP Power Saving Enable / Disable (sub)field alone may indicate whether the AP supports AP Power Saving. For example, if the AP supports Power Saving, the value of the AP Power Saving Enable / Disable (sub)field may have a value indicating that the AP Power Saving operation is enabled (e.g., 1) or disabled (e.g., 0). For example, if the AP does not support Power Saving, the value of the AP Power Saving Enable / Disable (sub)field may have only a value indicating that the AP Power Saving operation is disabled (e.g., 0). Accordingly, when the AP power saving enable / disable (sub)field is set to a value corresponding to enable (e.g., 1), it may be indicated that the AP supports AP power saving and performs AP power saving operations.

[0240] Additionally or alternatively, the AP Power Saving Enable / Disable (sub)field may be defined separately for different modes of AP Power Saving. For example, a Scheduled AP Power Saving Enable / Disable (sub)field, an Unscheduled AP Power Saving Enable / Disable (sub)field, and / or a Dynamic (AP) Power Saving Enable / Disable (sub)field may be defined separately.

[0241] Example 5

[0242] This embodiment relates to a listen interval exclusion (sub)field. For example, the listen interval exclusion (sub)field may be a new (sub)field.

[0243] If the value of the Listen Interval Exclusion (sub)field is the first value (e.g., 1), it may indicate that the beacon interval of the corresponding AP is excluded when setting the listen interval. Accordingly, the non-AP MLD may exclude the beacon interval of the corresponding AP and set the listen interval based on the beacon interval(s) of the remaining AP(s).

[0244] Additionally or alternatively, if a listen interval exclusion (sub)field exists, various (sub)field(s) described in Examples 1 to 4 above may be defined together. Instead of the non-AP STA of the non-AP MLD implicitly or indirectly determining whether to include or exclude the beacon interval of the said AP from the beacon interval(s) that form the basis of the listen interval based on the instruction information of the (sub)field of Examples 1 to 4 of the said AP, the determination of whether to include or exclude the beacon interval of the said AP from the beacon interval(s) that form the basis of the listen interval may be made according to the instruction of the explicit or direct listen interval exclusion (sub)field of the said AP.

[0245] In the example of FIG. 9, it can be assumed that AP1 of Link 1 provides first information related to its AP power saving (e.g., information on whether AP power saving is supported, whether scheduled AP power saving mode is supported, and / or whether unscheduled AP power saving mode is supported) and / or second information (e.g., information on AP power saving enable / disable, scheduled AP power saving mode enable / disable, and / or unscheduled AP power saving mode enable / disable). Such first information and / or second information may be provided from AP1 during the ML setup process. For example, if AP1's AP power saving support and / or enable is indicated, and / or a listen interval exclusion instruction is provided, the non-AP STA may exclude AP1's beacon interval from the beacon interval(s) that form the basis for the listen interval determination. Accordingly, the beacon interval (250ms) of Link 1 is excluded, and the listen interval of the non-AP STA(s) belonging to the non-AP MLD can be determined / applied based on the beacon interval (200ms) of Link 2.

[0246] Example 6

[0247] After the listen interval is set, if the AP power saving enable / disable (sub)field in the frame transmitted by the AP (e.g., data frame) has a value indicating that AP power saving is enabled, the STA of the non-AP MLD that receives this may send a request to the AP MLD for the purpose of changing / updating the listen interval (e.g., a listen interval update request).

[0248] A listen interval update request may include a listen interval value different from the initially configured listen interval value. If the AP MLD receiving the request accepts it, the new listen interval value included in the listen interval update request may be applied.

[0249] For example, in the example of FIG. 9, the value of the initially set listen interval between the AP MLD and the non-AP MLD may be set based on the value of the beacon interval of AP1, which indicates that AP power saving within the AP MLD is supported but disabled. Then, when the non-AP MLD receives the value indicating that AP1 enables AP power saving, the non-AP MLD may request a change to a shorter listen interval value by including the value of the beacon interval of AP2, another AP within the same AP MLD, instead of the value of the beacon interval of AP1, in the listen interval update request.

[0250] Alternatively, in the example of FIG. 9, after the listen interval is initially set or updated based on the beacon interval of AP2, AP1 may be disabled while supporting AP power saving, and the STA of the non-AP MLD may be instructed to do so. In this case, the non-AP MLD may request a change to a longer listen interval value by including the value of the beacon interval of AP1, rather than the value of the beacon interval of AP2, within the listen interval update request.

[0251] The embodiments described above are combinations of the components and features of the present disclosure in a specific form. Each component or feature should be considered optional unless otherwise explicitly stated. Each component or feature may be implemented in a form not combined with other components or features. Additionally, it is possible to construct embodiments of the present disclosure by combining some components and / or features. The order of operations described in the embodiments of the present disclosure may be changed. Some components or features of one embodiment may be included in another embodiment, or may be replaced with corresponding components or features of another embodiment. It is obvious that embodiments may be constructed by combining claims that are not explicitly related in the claims, or that they may be included as new claims by amendment after filing.

[0252] It is obvious to those skilled in the art that the present disclosure may be embodied in other specific forms without departing from the essential features of the present disclosure. Accordingly, the detailed description set forth above should not be interpreted restrictively in all respects and should be considered exemplary. The scope of the present disclosure shall be determined by a reasonable interpretation of the appended claims, and all modifications within the equivalent scope of the present disclosure are included within the scope of the present disclosure.

[0253] The scope of the present disclosure includes software or machine-executable instructions (e.g., operating systems, applications, firmware, programs, etc.) that enable 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, etc. are stored and executable on a device or computer. Instructions that may be used to program a processing system to perform the features described in the present disclosure may be stored on or within a storage medium or a computer-readable storage medium, and the features described in the present disclosure may be implemented using a computer program product comprising such a storage medium. The storage medium may include, but is not limited to, high-speed random access memory such as DRAM, SRAM, DDR RAM, or other random access solid-state memory devices, and may 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 may optionally include one or more storage devices located remotely from the processor(s). Memory or alternatively, non-volatile memory device(s) within memory comprises a non-transient computer-readable storage medium. The features described in this disclosure may be stored in any one of the machine-readable media and integrated into software and / or firmware that can control the hardware of a processing system and allow the processing system to interact with other mechanisms utilizing results according to the embodiments of this disclosure. Such software or firmware may include, but is not limited to, application code, device drivers, operating systems, and execution environments / containers.

[0254] Although the method proposed in this disclosure has been described with an example applied to an IEEE 802.11-based system, it can be applied to various wireless LANs or wireless communication systems in addition to IEEE 802.11-based systems.

Claims

1. A step of receiving one or more of a first information or a second information from one or more APs affiliated with an access point multi-link device (AP MLD) by a non-AP station (STA) affiliated with a non-AP multi-link device (non-AP MLD), The first information above relates to the support of a power-saving (PS) mode of one or more links of the AP MLD, and The second information above relates to the enable or disable of the PS mode of one or more links of the AP MLD; and The method includes the step of determining a listen interval by the non-AP STA based on one or more beacon intervals associated with the one or more APs, and A method wherein the one or more beacon intervals include a specific beacon interval of a specific AP among the one or more APs, based on one or more of the first information or the second information of the one or more APs.

2. In Paragraph 1, A method in which the above one or more beacon intervals do not include the beacon interval of an AP or link in which the support of the PS mode is indicated by the first information.

3. In Paragraph 1, A method in which one or more beacon intervals include a beacon interval of an AP or link in which the PS mode is not supported by the first information.

4. In Paragraph 1, A method in which the above one or more beacon intervals do not include the beacon interval of an AP or link in which the enable of the PS mode is indicated by the second information.

5. In Paragraph 1, A method in which one or more beacon intervals include a beacon interval of an AP or link in which the disable of the PS mode is indicated by the second information.

6. In Paragraph 1, A method in which the one or more beacon intervals above do not include a beacon interval of an AP or link in which the support of the PS mode is indicated by the first information and the enable of the PS mode is indicated by the second information.

7. In Paragraph 1, A method comprising one or more beacon intervals, wherein the beacon interval of an AP or link is indicated by the first information that the PS mode is supported and by the second information that the PS mode is disabled.

8. In Paragraph 3, A method in which the above one or more beacon intervals are not based on the second information regarding the AP or the link in which the PS mode is not supported by the first information.

9. In Paragraph 1, A method in which, based on the enable of the PS mode for a specific link being indicated by the second information above, an update request for a listen interval based on one or more beacon intervals not including the beacon interval of the specific link is transmitted from the non-AP STA to the AP MLD.

10. In Paragraph 9, A method in which an updated listen interval is applied by the non-AP STA based on receiving from the AP MLD a response indicating permission for the above request.

11. In Paragraph 1, The above-mentioned listen interval is based on the maximum value among the above-mentioned one or more beacon intervals.

12. In Paragraph 1, A method provided to the non-AP STA through a beacon frame from one or more of the first information or the second information.

13. In Paragraph 1, A method in which the above first information is provided to the above non-AP STA through a multi-link setup process.

14. In Paragraph 1, A method in which, after a multi-link setup process, the second information is provided to the non-AP STA through one or more of a control frame, a management frame, or a data frame.

15. In a non-AP station (STA) affiliated with a non-access point multi-link device (non-AP MLD), the non-AP STA is: One or more transceivers; and It includes one or more processors connected to the above one or more transmitters and receivers, and The above one or more processors are: Through the above-mentioned one or more transceivers, one or more of the first information or the second information are received from one or more APs belonging to an access point multi-link device (AP MLD), and The first information above relates to the support of a power-saving (PS) mode of one or more links of the AP MLD, and The second information above relates to the enable or disable of the PS mode of one or more links of the AP MLD; and It is configured to determine a listen interval based on one or more beacon intervals associated with the above one or more APs, and The above one or more beacon intervals include a specific beacon interval of a specific AP among the one or more APs, based on one or more of the first information or the second information of the one or more APs, a non-AP STA.

16. A step of transmitting one or more of the first information or the second information to a non-AP station (STA) affiliated with a non-access point multi-link device (non-AP MLD) by a first AP affiliated with an access point multi-link device (AP MLD). The above first information relates to the support of a power-saving (PS) mode of the link of the above first AP, and The second information above relates to the enable or disable of the PS mode of the link of the first AP; and The method includes the step of performing transmission or reception with the non-AP STA based on a listen interval based on one or more beacon intervals associated with one or more APs, including the first AP belonging to the AP MLD. A method wherein the one or more beacon intervals include a specific beacon interval of a specific AP among the one or more APs based on one or more of the first information or the second information of the one or more APs including the first AP.

17. In a first AP affiliated with an access point multi-link device (AP MLD), the first AP: One or more transceivers; and It includes one or more processors connected to the above one or more transmitters and receivers, and The above one or more processors are: One or more of the first information or the second information are transmitted to a non-AP station (STA) belonging to a non-access point multi-link device (non-AP MLD) through the above-mentioned one or more transceivers, and The above first information relates to the support of a power-saving (PS) mode of the link of the above first AP, and The second information above relates to the enable or disable of the PS mode of the link of the first AP; and Based on a listen interval based on one or more beacon intervals associated with one or more APs including the first AP belonging to the AP MLD, transmission or reception with the non-AP STA is configured to be performed through the one or more transceivers, and The above one or more beacon intervals include a first AP comprising a specific beacon interval of a specific AP among the one or more APs, based on one or more of the first information or the second information of the one or more APs including the first AP.

18. One or more processors; and A processing device comprising one or more computer memories that are operably connected to one or more processors and store instructions for performing a method according to any one of claims 1 to 14 based on execution by one or more processors.

19. One or more non-transitory computer-readable media storing one or more instructions that are executed by one or more processors to control the execution of a method according to any one of claims 1 through 14.

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