Wireless communication method using multiple links and wireless communication terminal using same

Abstract

A non-access point (AP) multilink device (MLD) including a plurality of stations operating on a plurality of links in a wireless communication system of the present invention may receive a frame from an AP MLD including a plurality of APs operating on the plurality of links, and each of the one or more TBTT information fields may be processed based on the TBTT information type subfield and the TBTT information length field included in the frame.

Description

Technical Field

[0001] The present invention relates to a wireless communication method using multi-links and a wireless communication terminal using the method. Background Art

[0002] In recent years, as the supply of mobile devices has expanded, wireless LAN (Wireless LAN) technology that can provide fast wireless Internet services to mobile devices has received attention. Wireless LAN technology allows mobile devices including smart phones, smart tablets, laptops, portable multimedia players, embedded devices, etc. to wirelessly access the Internet in homes, companies, or special service provision areas based on short-range wireless communication technology.

[0003] Since the initial wireless LAN technology was supported using the 2.4 GHz frequency, the Institute of Electrical and Electronics Engineers (IEEE) Electrical and Electronics Engineers (IEEE) 802.11 has been commercialized or developed various technical standards. First, IEEE 802.11b supports a communication speed of up to 11 Mbps when using the frequency of the 2.4 GHz band. Compared with the frequency of the 2.4 GHz band that is significantly congested, the IEEE 802.11a commercialized after IEEE 802.11b uses a frequency of the 5 GHz band instead of the 2.4 GHz band to reduce the influence of interference, and by using OFDM technology, the communication speed is increased to a maximum of 54 Mbps. However, the shortcoming of IEEE 802.11a is that the communication distance is shorter than that of IEEE 802.11b. In addition, similar to IEEE 802.11b, IEEE 802.11g uses the frequency of the 2.4 GHz band to achieve a communication speed of up to 54 Mbps and meets backward compatibility to significantly attract attention, and further, in terms of communication distance, it is superior to IEEE 802.11a.

[0004] In addition, as a technical standard established to overcome the limitation of communication speed pointed out as a weakness in wireless LAN, IEEE 802.11n has been provided. IEEE 802.11n aims to improve the speed and reliability of the network and extend the working distance of the wireless network. In more detail, IEEE 802.11n supports high throughput (HT), in which the data processing speed is a maximum of 540Mbps or higher, and further, based on multiple inputs and multiple outputs (MIMO) technology, in which multiple antennas are used on both sides of the transmission unit and the receiving unit to minimize transmission errors and optimize data speed. In addition, the standard can use a coding scheme of transmitting multiple copies superimposed on each other in order to increase data reliability.

[0005] As the provision of wireless LANs becomes active, and further, as the applications using wireless LANs are diversified, the demand for new wireless LAN systems supporting higher throughput (Very High Throughput (VHT)) than the data processing speed supported by IEEE 802.11n has attracted attention. Among them, IEEE 802.11ac supports a bandwidth (80 to 160 MHz) in the 5 GHz frequency. The IEEE 802.11ac standard is defined only in the 5 GHz band, but the initial 11ac chipset supports even operation in the 2.4 GHz band for backward compatibility with existing 2.4 GHz band products. Theoretically, according to the standard, the wireless LAN speed of multiple stations can be enabled to reach a minimum of 1 Gbps, and the maximum single link speed can be enabled to reach a minimum of 500 Mbps. This is achieved by extending the concept of the wireless interface received by 802.11n, such as a wider wireless frequency bandwidth (maximum 160 MHz), more MIMO spatial streams (maximum 8), multi-user MIMO, and high-density modulation (maximum 256QAM). In addition, as a scheme for transmitting data by using the 60 GHz band instead of the existing 2.4 GHz / 5 GHz, IEEE 802.11ad has been provided. IEEE 802.11ad is a transmission standard that provides a maximum speed of 7 Gbps by using a beamforming technology, and is suitable for high bit rate moving image streams such as large-scale data or non-compressed HD video. However, since the 60 GHz band is difficult to pass through obstacles, it has a disadvantage in that the 60 GHz band can be used only among devices in a close space.

[0006] As a wireless LAN standard following 802.11ac and 802.11ad, the IEEE 802.11ax (High Efficiency Wireless LAN, HEW) standard for providing efficient and high-performance wireless LAN communication technology in a high-density environment where APs and terminals are concentrated is in the development completion stage. In a wireless LAN environment based on 802.11ax, communication with high-frequency efficiency should be provided indoors / outdoors in the presence of high-density stations and access points (APs), and various technologies to achieve such communication have been developed.

[0007] In order to support new multimedia applications, such as high-definition video and real-time gaming, new wireless LAN standards have been developed to increase the maximum transmission rate. In the IEEE 802.11be Extremely High Throughput (EHT), the 7th generation wireless LAN standard, the standard is being developed with the goal of supporting transmission rates up to 30 Gbps in the 2.4 / 5 / 6 GHz band through wider bandwidth, increased spatial streams, multi-AP collaboration, etc. Summary of the invention

[0008] Technical issues

[0009] An embodiment of the present invention is directed to providing a wireless communication method using multi-links and a wireless communication terminal using the method.

[0010] The technical problems to be achieved in this specification are not limited to the technical problems mentioned above, and those skilled in the art can clearly understand other technical problems not mentioned based on the following description.

[0011] Technical methods

[0012] In a multi-link device (MLD) including a plurality of stations each operating in a plurality of links according to the present invention, the multi-link device (MLD) including a plurality of stations each operating in a plurality of links includes a transceiver unit and a processor, wherein the processor receives a frame from an AP of the AP MLD including a plurality of access points (APs), wherein the frame includes a reduced neighbor report (RNR) element, the RNR element includes one or more neighbor AP information fields, the neighbor AP information fields including information related to the AP Information related to other APs included in the MLD, and wherein the neighbor AP information field includes a target beacon transmission time (TBTT) information setting field, and the TBTT information setting field includes a TBTT information field type subfield, a TBTT information length field, and one or more TBTT information fields; based on the TBTT information type subfield and the TBTT information length field, processing is performed on each of the one or more TBTT information fields, wherein, when the value of the TBTT information type subfield is "0", by comparing the value of the TBTT information length field with the first threshold and / or the second threshold, each of the one or more TBTT information fields is only processed to the first octet value or the second octet value, and wherein, when the value of the TBTT information type subfield is "1", by comparing the value of the TBTT information length field with the third threshold, each of the one or more TBTT information fields is only processed to the third octet value.

[0013] In addition, in the present invention, the TBTT information field type subfield is used to indicate the content and / or length of the one or more TBTT information fields, and the TBTT information length field indicates the length of each of the one or more TBTT information fields.

[0014] In addition, in the present invention, when the value of the TBTT information type subfield is "0" and the value of the TBTT information length field is less than the first threshold and equal to or greater than the second threshold, each of the one or more TBTT information fields is processed only up to the second octet value, and the second octet value is less than the first octet value.

[0015] In addition, in the present invention, in each of the one or more TBTT information fields, the remaining octets except the values ​​up to the second octet value are not processed.

[0016] In addition, in the present invention, when the value of the TBTT information type subfield is "0" and the value of the TBTT information length field is equal to or greater than the first threshold, the one or more TBTT information fields are only processed up to the first octet value, and the second octet value is less than the first octet value.

[0017] In addition, in the present invention, in each of the one or more TBTT information fields, the remaining octets except the values ​​up to the first octet value are not processed.

[0018] In addition, in the present invention, when the value of the TBTT information type subfield is "0" and the value of the TBTT information length field is less than the second threshold, the one or more TBTT information fields are not processed.

[0019] In addition, in the present invention, when the value of the TBTT information type subfield is "1" and the value of the TBTT information length field is greater than or equal to the third threshold, the one or more TBTT information fields are only processed up to the third octet value.

[0020] In addition, in the present invention, in each of the one or more TBTT information fields, the remaining octets except the values ​​up to the third octet value are not processed.

[0021] In addition, in the present invention, when the value of the TBTT information type subfield is "1" and the value of the TBTT information length field is less than the third threshold, the one or more TBTT information fields are not processed.

[0022] In addition, in the present invention, each of the one or more TBTT information fields includes a neighbor AP TBTT offset subfield, and the neighbor AP TBTT offset subfield indicates the offset between the TBTT used by the AP to send beacon frames and the TBTT used by another AP to send beacon frames.

[0023] In addition, in the present invention, when the other AP is included in the AP MLD, the offset value indicated by the neighbor AP TBTT offset subfield is set to a value other than a preset value related to "unknown".

[0024] In addition, in the present invention, the preset value is "255".

[0025] In addition, the present invention also provides a method, the method comprising the following steps: receiving a frame from an AP of an APMLD including a plurality of access points (APs), wherein the frame comprises a reduced neighbor report (RNR) element, the RNR element comprises one or more neighbor AP information fields, the neighbor AP information field comprises information related to the AP Information related to other APs included in the MLD, and wherein the neighbor AP information field includes a target beacon transmission time (TBTT) information setting field, and the TBTT information setting field includes a TBTT information field type subfield, a TBTT information length field, and one or more TBTT information fields; and each of the one or more TBTT information fields is processed based on the TBTT information type subfield and the TBTT information length field, wherein, when the value of the TBTT information type subfield is "0", by comparing the value of the TBTT information length field with the first threshold and / or the second threshold, each of the one or more TBTT information fields is only processed to the first octet value or the second octet value, and wherein, when the value of the TBTT information type subfield is "1", by comparing the value of the TBTT information length field with the third threshold, each of the one or more TBTT information fields is only processed to the third octet value.

[0026] Beneficial Effects

[0027] One embodiment of the present invention provides a wireless communication method for effectively using multiple links and a wireless communication terminal using the method.

[0028] Effects obtainable in the present invention are not limited to the above-mentioned effects, and other effects not mentioned can be clearly understood from the following description by those skilled in the art to which the present invention pertains. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 A wireless LAN system according to an embodiment of the present invention is shown.

[0030] Figure 2 A wireless LAN system according to another embodiment of the present invention is shown.

[0031] Figure 3 The configuration of a station according to an embodiment of the present invention is shown.

[0032] Figure 4 The configuration of the access point according to the embodiment of the present invention is shown.

[0033] Figure 5 The process of setting up a link between a station and an access point is schematically shown.

[0034] Figure 6The following describes a Carrier Sense Multiple Access (CSMA) / Collision Avoidance (CA) method used in wireless LAN communications.

[0035] Figure 7 Embodiments of the format of a PLCP Protocol Data Unit (PPDU) for each of the various standard generations are shown.

[0036] Figure 8 Examples of various extremely high throughput (EHT) physical protocol data unit (PPDU) formats and a method for indicating the formats according to an embodiment of the present invention are shown.

[0037] Fig. 9 is a diagram showing a multi-link device according to an embodiment of the present invention.

[0038] Fig.10 is a diagram showing an example of a TID-to-link mapping method according to an embodiment of the present invention.

[0039] Fig.11 is a diagram showing an example of a multi-link NAV setting operation according to an embodiment of the present invention.

[0040] Fig.12 is a diagram showing another example of a multi-link NAV setting operation according to an embodiment of the present invention.

[0041] Fig.13 is a diagram showing an example of BSS classification and an operation based on the BSS classification according to an embodiment of the present invention.

[0042] Fig.14 A wireless LAN function according to an embodiment of the present invention is shown.

[0043] Fig.15 An uplink (UL) multi-user (MU) operation according to an embodiment of the present invention is shown.

[0044] Fig.16 The trigger frame format according to an embodiment of the present invention is shown.

[0045] Fig.17 A method for indicating a trigger-based PPDU format according to an embodiment of the present invention is shown.

[0046] Fig.18An example of UL MU operation according to an embodiment of the present invention is shown.

[0047] Fig.19 A power management operation performed by a station according to an embodiment of the present invention is shown.

[0048] Fig. 20 The format of a TIM element according to an embodiment of the present invention is shown.

[0049] Fig.21 The format of a multi-link traffic element according to an embodiment of the present invention is shown.

[0050] Fig. 22 A method for signaling traffic buffered in an AP multi-link device using a multi-link traffic element and a partial virtual bitmap subfield of a TIM element according to an embodiment of the present invention is shown.

[0051] Fig.23 A method for setting a multi-link traffic element according to an embodiment of the present invention is shown.

[0052] Fig.24 The method for setting the per-link traffic bitmap subfield of a multi-link traffic element according to an embodiment of the present invention is shown when the link set operated by an AP multi-link device and the link set operated by a non-AP multi-link device communicating with the AP multi-link device are different.

[0053] Fig.25 Signaling related to multilink elements and MediumSyncDelay according to an embodiment of the present invention is shown.

[0054] Fig.26 The multi-link setting process according to an embodiment of the present invention is shown.

[0055] Fig. 27 The format of the reduced neighbor report element according to an embodiment of the present invention is shown.

[0056] Fig.28 A method for setting an ID of a multi-link device according to an embodiment of the present invention is shown.

[0057] Fig.29 A method for allocating AIDs to non-AP stations attached to a multi-link device according to an embodiment of the present invention is shown.

[0058] Fig.30 A method for allocating AIDs to non-AP stations attached to a multi-link device according to an embodiment of the present invention is shown.

[0059] Fig.31 A TID-to-link mapping negotiation is shown in which an AP multi-link device sends a TID-to-link mapping request according to an embodiment of the present invention.

[0060] Fig.32 A TID-to-link mapping negotiation is shown in which an AP multi-link device sends a TID-to-link mapping request according to an embodiment of the present invention.

[0061] Fig.33 TID-to-link mapping negotiation is shown when a link set for which TID-to-link mapping is requested is different from a link set set by a TID-to-link mapping response according to an embodiment of the present invention.

[0062] Fig.34 It is a diagram showing an example of the format of the TBTT information field (TBTT Information field format) according to an embodiment of the present invention.

[0063] Fig.35 is a diagram showing an example of a reception and processing operation of a Neighbor AP Information field according to an embodiment of the present invention.

[0064] Fig.36 is a diagram showing an example of a reception and processing operation of a Neighbor AP Information field according to an embodiment of the present invention.

[0065] Fig.37 is a diagram showing an example of transmission of a beacon frame and TBTT offset according to an embodiment of the present invention.

[0066] Fig.38 is a diagram showing a configuration example of a multi-link and a multi-BSSID set according to an embodiment of the present invention.

[0067] Fig.39 is a diagram showing another example of a configuration of a multi-link and a multi-BSSID set according to an embodiment of the present invention.

[0068] Fig.40 is a diagram showing another example of a configuration of a multi-link and a multi-BSSID set according to an embodiment of the present invention.

[0069] Fig.41 is a diagram showing an example of EHT operation elements according to an embodiment of the present invention.

[0070] Fig.42 is a diagram showing an example of a traffic indicator virtual bitmap according to an embodiment of the present invention.

[0071] Fig.43 is a diagram showing another example of a traffic indicator virtual bitmap according to an embodiment of the present invention.

[0072] Fig.44is a diagram showing an example of multi-link setting according to an embodiment of the present invention.

[0073] Fig.45 is a diagram showing an example of configuration of a Reduced Neighbor Report (RNR) element and transmission of a beacon frame according to an embodiment of the present invention.

[0074] Fig.46 is a diagram showing an example of a multilink element according to an embodiment of the present invention.

[0075] Fig.47 is a diagram showing an example of an operation method of an MLD according to an embodiment of the present invention. DETAILED DESCRIPTION

[0076] By considering the functions of the present invention, the terms used in this specification adopt the common terms widely used at present, but the terms can be changed according to the intentions, habits and emergence of new technologies of those skilled in the art. In addition, in special cases, there are terms arbitrarily selected by the applicant, and in this case, their meanings will be explained in the corresponding description part of the present invention. Therefore, it should be understood that the terms used in this specification will not only be analyzed based on the name of the term, but also based on the essential meaning of the term and the content of the entire specification.

[0077] Throughout the specification, when an element is described as being "coupled" to another element, the element may be "directly coupled" to the other element, or "electrically coupled" to the other element via a third element. In addition, unless explicitly stated to the contrary, the word "comprising" will be understood to implicitly include the stated elements, but not to exclude any other elements. In addition, limitations such as "or above" or "or below" based on special thresholds may be appropriately replaced with "greater than" or "less than", respectively.

[0078] Hereinafter, in the present invention, field and subfield may be used interchangeably.

[0079] Figure 1 A wireless LAN system according to an embodiment of the present invention is shown.

[0080] A wireless LAN system includes one or more Basic Service Sets (BSSs), and a BSS represents a collection of devices that successfully synchronize with each other to communicate with each other. Generally, a BSS can be divided into an infrastructure BSS and an independent BSS. Figure 1 An infrastructure BSS is shown between them.

[0081] like Figure 1As shown, the infrastructure BSS (BSS1 and BSS2) includes one or more stations (STA 1, STA 2, STA 3, STA 4 and STA5), access points (AP-1 and AP-2) that serve as stations providing distribution services (Distribution Service), and a distribution system (Distribution System, DS) that connects multiple access points (AP-1 and AP-2).

[0082] A station (STA) is a predetermined device including a medium access control (MAC) and a physical layer (Physical Layer) interface for a wireless medium in accordance with the provisions of the IEEE 802.11 standard, and broadly includes both non-access point (non-AP) stations and access points (APs). In addition, in this specification, the term "terminal" may be used to refer to a non-AP STA or an AP, or both terms. A station for wireless communication includes a processor and a communication unit, and may further include a user interface unit and a display unit according to an embodiment. The processor may generate a frame to be transmitted via a wireless network, or process a frame received via a wireless network, and further, perform various processes for controlling the station. In addition, the communication unit is functionally connected to the processor, and transmits and receives frames via a wireless network for the station. According to the present invention, a terminal may be used as a term including a terminal (user equipment, UE).

[0083] An access point (AP) is an entity that provides access to a distributed system (DS) via a wireless medium for stations associated therewith. In an infrastructure BSS, communication among non-AP stations is performed in principle via an AP, but when a direct link is configured, direct communication is allowed even among non-AP stations. Meanwhile, in the present invention, AP is used as a concept including a personal BSS coordination point (PCP), and in a broad sense may include concepts such as a central controller, a base station (BS), a node B, a base transceiver system (BTS), or a station controller. In the present invention, AP may also be referred to as a base station wireless communication terminal. A base station wireless communication terminal may be used as a term that includes AP, a base station, an eNodeB (eNB), and a transmission point (TP) in a broad sense. In addition, a base station wireless communication terminal may include various types of wireless communication terminals that allocate communication medium resources and perform scheduling in communications with multiple wireless communication terminals.

[0084] Multiple infrastructure BSSs may be connected to each other via a distribution system (DS). In this case, multiple BSSs connected via a distribution system are called an extended service set (ESS).

[0085] Figure 2 FIG. 2 shows an independent BSS according to another embodiment of the present invention, which is a wireless LAN system. Figure 2 In the embodiment, Figure 1 Same as or corresponding to Figure 1 Repetitive description of parts of the embodiments will be omitted.

[0086] Because in Figure 2 The BSS3 shown in FIG. 1 is an independent BSS and does not include an AP, and all stations STA6 and STA7 are not connected to the AP. An independent BSS is not allowed to access a distributed system and forms a self-contained network. In an independent BSS, corresponding stations STA6 and STA7 can be directly connected to each other.

[0087] Figure 3 FIG. 1 is a block diagram showing a configuration of a station 100 according to an embodiment of the present invention. Figure 3 As shown in FIG. 1 , the station 100 according to an embodiment of the present invention may include a processor 110 , a communication unit 120 , a user interface unit 140 , a display unit 150 , and a memory 160 .

[0088] First, the communication unit 120 transmits and receives wireless signals, such as wireless LAN packets, etc., and may be embedded in the station 100 or provided as a peripheral. According to an embodiment, the communication unit 120 may include at least one communication module using different frequency bands. For example, the communication unit 120 may include communication modules having different frequency bands (such as 2.4GHz, 5GHz, 6GHz, and 60GHz). According to an embodiment, the station 100 may include a communication module using a frequency band of 7.125GHz or above, and a communication module using a frequency band of 7.125GHz or below. Each communication module may perform wireless communication with an AP or an external station according to the wireless LAN standard of the frequency band supported by the corresponding communication module. The communication unit 120 may operate only one communication module at a time, or operate multiple communication modules together at the same time, according to the performance and requirements of the station 100. When the station 100 includes multiple communication modules, each communication module may be implemented by an independent component, or multiple modules may be integrated into one chip. In an embodiment of the present invention, the communication unit 120 may represent an RF communication module for processing a radio frequency (RF) signal.

[0089] Second, the user interface unit 140 includes various types of input / output devices provided in the station 100. That is, the user interface unit 140 can receive user input by using various input devices, and the processor 110 can control the station 100 based on the received user input. In addition, the user interface unit 140 can perform output based on the command of the processor 110 by using various output devices.

[0090] Next, the display unit 150 outputs an image on the display screen. The display unit 150 may output various display objects, such as content or a user interface executed by the processor 110, etc., based on the control command of the processor 110. In addition, the memory 160 stores a control program and various data used in the station 100. The control program may include an access program required for the station 100 to access an AP or an external station.

[0091] The processor 110 of the present invention may execute various commands or programs and process data in the station 100. In addition, the processor 110 may control various units of the station 100 and control data transmission / reception among the units. According to an embodiment of the present invention, the processor 110 may execute a program for accessing an AP stored in the memory 160 and receive a communication configuration message transmitted by the AP. In addition, the processor 110 may read information about the priority condition of the station 100 included in the communication configuration message and request access to the AP based on the information about the priority condition of the station 100. The processor 110 of the present invention may represent a main control unit of the station 100, and according to an embodiment, the processor 110 may represent a control unit for individually controlling certain components of the station 100 (e.g., the communication unit 120, etc.). That is, the processor 110 may be a modem or a modulator / demodulator for modulating a wireless signal transmitted to the communication unit 120 and demodulating a wireless signal received from the communication unit 120. The processor 110 controls various operations of wireless signal transmission / reception of the station 100 according to an embodiment of the present invention. A detailed embodiment thereof will be described below.

[0092] exist Figure 3 The station 100 shown in is a block diagram according to an embodiment of the present invention, where the separated blocks are shown as elements of a logically distinguished device. Therefore, the elements of the device can be installed in a single chip or multiple chips according to the design of the device. For example, the processor 110 and the communication unit 120 can be implemented when integrated into a single chip, or as separate chips. In addition, in an embodiment of the present invention, some components of the station 100, such as the user interface unit 140 and the display unit 150, etc., can be selectively provided in the station 100.

[0093] Figure 4 FIG. 2 is a block diagram showing a configuration of an AP 200 according to an embodiment of the present invention. Figure 4 As shown in FIG. 2 , the AP 200 according to the embodiment of the present invention may include a processor 210, a communication unit 220, and a memory 260. Figure 4 Among the components of AP 200, Figure 2 The components of station 100 are the same as or correspond to Figure 2 A repeated description of some of the components of the station 100 will be omitted.

[0094] Reference Figure 4 , the AP 200 according to the present invention includes a communication unit 220 that operates a BSS in at least one frequency band. Figure 3 As described in the embodiment of the present invention, the communication unit 220 of the AP 200 may also include a plurality of communication modules using different frequency bands. That is, the AP 200 according to the embodiment of the present invention may include two or more communication modules in different frequency bands (e.g., 2.4 GHz, 5 GHz, 6 GHz, and 60 GHz) together. Preferably, the AP 200 may include a communication module using a frequency band of 7.125 GHz or above, and a communication module using a frequency band of 7.125 GHz or below. Each communication module may perform wireless communication with a station according to the wireless LAN standard of the frequency band supported by the corresponding communication module. The communication unit 220 may operate only one communication module at a time, or operate a plurality of communication modules together at the same time, according to the performance and requirements of the AP 200. In an embodiment of the present invention, the communication unit 220 may represent a radio frequency (RF) communication module for processing RF signals.

[0095] Next, the memory 260 stores the control program and various result data used in the AP 200. The control program may include an access program for managing the access of the station. In addition, the processor 210 may control the various units of the AP 200 and control the data transmission / reception among the units. According to an embodiment of the present invention, the processor 210 may execute the program for accessing the station stored in the memory 260 and transmit a communication configuration message for one or more stations. In this case, the communication configuration message may include information about the access priority conditions of the various stations. In addition, the processor 210 performs access configuration according to the access request of the station. According to an embodiment, the processor 210 may be a modem or a modulator / demodulator for modulating the wireless signal transmitted to the communication unit 220 and demodulating the wireless signal received from the communication unit 220. The processor 210 controls various operations according to an embodiment of the present invention, such as the wireless signal transmission / reception of the AP 200. Its detailed embodiment will be described below.

[0096] Figure 5 is a diagram schematically showing a process in which a STA sets up a link with an AP.

[0097] Reference Figure 5 In a broad sense, a link between the STA 100 and the AP 200 is set up via three steps of scanning, authentication, and association. First, the scanning step is a step in which the STA 100 obtains access information of a BSS operated by the AP 200. Methods for performing scanning include a passive scanning method in which the AP 200 obtains information by using a beacon message (S101) transmitted periodically, and an active scanning method in which the STA 100 transmits a probe request to the AP (S103), and obtains access information by receiving a probe response from the AP (S105).

[0098] The STA 100 that successfully receives the wireless access information in the scanning step performs an authentication step by transmitting an authentication request (S107a) and receiving an authentication response (S107b) from the AP 200. After performing the authentication step, the STA 100 performs an association step by transmitting an association request (S109a) and receiving an association response (S109b) from the AP 200. In this specification, association basically refers to wireless association, but the present invention is not limited thereto, and association can broadly include both wireless association and wired association.

[0099] At the same time, an authentication step (S111) based on 802.1X and an IP address acquisition step (S113) via DHCP may be further performed. Figure 5 In the present invention, the authentication server 300 is a server that processes 802.1X-based authentication for the STA 100, and may exist in physical association with the AP 200, or exist as a separate server.

[0100] Figure 6 The diagram shows a Carrier Sense Multiple Access (CSMA) / Collision Avoidance (CA) method used in wireless LAN communication.

[0101] A terminal performing wireless LAN communication confirms whether a channel is busy by performing carrier sensing before transmitting data. When a wireless signal with a preset strength or greater is sensed, the corresponding channel is determined to be busy and the terminal delays access to the corresponding channel. This process is called Clear Channel Assessment (CCA), and the level that determines whether the corresponding signal is sensed is called the CCA threshold. When a wireless signal with a CCA threshold or higher received by the terminal indicates the corresponding terminal as a recipient, the terminal processes the received wireless signal. At the same time, when no wireless signal is detected in the corresponding channel or a wireless signal with a strength less than the CCA threshold is detected, the channel is determined to be idle.

[0102] When it is determined that the channel is idle, each terminal with data to be transmitted performs a backoff process after an inter-frame space (IFS) time, which depends on the situation of each terminal, for example, after arbitration IFS (AIFS), PCF IFS (PIFS), etc. According to this embodiment, AIFS can be used as a component to replace the existing DCF IFS (DIFS). Each terminal waits while reducing the time slot time as long as the random number determined by the corresponding terminal during the interval of the idle state of the channel, and the terminal that completely runs out of the time slot time attempts to access the corresponding channel. In this way, the interval in which each terminal performs the backoff process is called a contention window interval. At this time, the random number can be called a backoff counter. That is, the initial value of the backoff counter is set by the random number integer obtained by the terminal. If the terminal detects that the channel is idle within the time slot time, the terminal can reduce the backoff counter by 1. In addition, when the backoff counter reaches 0, the terminal may be allowed to perform channel access on the corresponding channel. Therefore, if the channel is idle within the AIFS time and the time slot time of the backoff counter, the terminal may be allowed to transmit.

[0103] When the special terminal successfully accesses the channel, the corresponding terminal can transmit data through the channel. However, when the terminal attempting to access conflicts with another terminal, the terminals that conflict with each other are respectively assigned new random numbers to perform the backoff process again. According to an embodiment, the random number newly assigned to each terminal can be determined within a range (2*CW), which is twice the range (contention window CW) of the random number previously assigned to the corresponding terminal. At the same time, each terminal attempts to access by performing the backoff process again in the next contention window interval, and in this case, each terminal performs the backoff process from the remaining time slot time in the previous contention window interval. In this way, each terminal performing wireless LAN communication can avoid mutual conflict of special channels.

[0104] <Examples of various PPDU formats>

[0105] Figure 7 An example of the format of a PLCP Protocol Data Unit (PPDU) for each of the various standard generations is shown. More specifically, Figure 7 (a) shows an embodiment of a conventional PPDU format based on 802.11a / g, Figure 7 (b) shows an embodiment of the HE PPDU format based on 802.11ax, and Figure 7(c) shows an embodiment of a non-legacy PPDU (ie, EHT PPDU) format based on 802.11be. Figure 7 (d) shows a detailed field configuration of RL-SIG and L-SIG commonly used in the PPDU format.

[0106] Reference Figure 7 (a), the preamble of the legacy PPDU includes a legacy short training field (Legacy Short Training field, L-STF), a legacy long training field (Legacy Long Training field, L-LTF) and a legacy signal field (Legacy Signal field, L-SIG). In an embodiment of the present invention, L-STF, L-LTF and L-SIG may be referred to as a legacy preamble.

[0107] Reference Figure 7 (b), the preamble of the HE PPDU also includes a repeated legacy short training field (RL-SIG), a high efficiency signal A field (HE-SIG-A), a high efficiency signal B field (HE-SIG-B), a high efficiency short training field (HE-STF) and a high efficiency long training field (HE-LTF) in the legacy preamble. In an embodiment of the present invention, RL-SIG, HE-SIG-A, HE-SIG-B, HE-STF and HE-LTF may be referred to as HE preambles. The detailed configuration of the HE preamble may be modified according to the HE PPDU format. For example, HE-SIG-B may be used only in the HE MU PPDU format.

[0108] Reference Figure 7(c), the EHT PPDU also includes a repeated legacy short training field (Repeated Legacy Short Training field, RL-SIG), a universal signal field (U-SIG) and an extremely high throughput signal A field (Extremely High Throughput Signal A field, EHT-SIG-A), an extremely high throughput signal B field (Extremely High Throughput Signal B field, EHT-SIG-B), an extremely high throughput short training field (Extremely High Throughput Short Training field, EHT-STF) and an extremely high throughput long training field (Extremely High Throughput Long Training field, EHT-LTF) in the traditional preamble. In an embodiment of the present invention, RL-SIG, EHT-SIG-A, EHT-SIG-B, EHT-STF and EHT-LTF may be referred to as EHT preambles. The specific configuration of the non-traditional preamble may be modified according to the EHT PPDU format. For example, EHT-SIG-A and EHT-SIG-B may be used only in a portion of the EHT PPDU format.

[0109] 64-FFT OFDM is applied to the L-SIG field included in the preamble of the PPDU, and the L-SIG field includes a total of 64 subcarriers. Among the 64 subcarriers, 48 ​​subcarriers other than the guard subcarrier, the DC subcarrier, and the pilot subcarrier are used for transmission of L-SIG data. BPSK and a modulation and coding scheme (MCS) of code rate = 1 / 2 are applied to the L-SIG, so the L-SIG can include a total of 24 bits of information. Figure 7 (d) shows the configuration of 24-bit information of L-SIG.

[0110] Reference Figure 7(d), L-SIG includes an L_RATE field and an L_LENGTH field. The L_RATE field includes 4 bits and indicates the MCS used for data transmission. Specifically, the L_RATE field indicates a value of a transmission rate of 6 / 9 / 12 / 18 / 24 / 36 / 48 / 54 Mbps obtained by combining a modulation scheme such as BPSK / QPSK / 16-QAM / 64-QAM with a non-efficiency such as 1 / 2, 2 / 3, 3 / 4, etc. The total length of the corresponding PPDU can be indicated by combining the information of the L_RATE field and the information of the L_LENGTH field. In the non-traditional PPDU format, the L_RATE field is configured to a minimum rate of 6 Mbps.

[0111] The unit of the L_LENGTH field can be allocated a total of 12 bits per byte, can be transmitted up to 4095 by signaling, and can indicate the length of the corresponding PPDU by combining with the L_RATE field. In this case, the legacy terminal and the non-legacy terminal can use different methods to interpret the L_LENGTH field.

[0112] First, the method by which a conventional terminal or a non-conventional terminal uses the L_LENGTH field to analyze the length of a corresponding PPDU is as follows. When the value of the L_RATE field is set to indicate 6Mbps, 3 bytes (i.e., 24 bits) can be transmitted during 4us, which is the duration of one symbol of 64FFT. Therefore, 3 bytes corresponding to the SVC field and the tail field are added to the value of the field L_LENGTH, and the added value is divided by 3 bytes as the transmission amount of one symbol, thereby obtaining the number of symbols based on 64FFT after L-SIG. The obtained number of symbols is multiplied by 4 us (ie, the length of one symbol), and then add the time 20us required for the transmission of L-STF, L-LTF and L-SIG to obtain the length of the corresponding PPDU, that is, the reception time RXTIME. This can be expressed by the following equation 1.

[0113] [Equation 1]

[0114]

[0115] in this case, represents the smallest natural number greater than or equal to x. Since the maximum value of the L_LENGTH field is 4095, the length of the PPDU can be set to be as long as 5.464ms. A non-legacy terminal transmitting a PPDU should set the L_LENGTH field as shown in Equation 2 below.

[0116] [Equation 2]

[0117]

[0118] Here, TXTIME is the total transmission time constituting the corresponding PPDU and is represented by the following Equation 3. In this case, TX represents the transmission time of X.

[0119] [Equation 3]

[0120] TXTIME(us)=T L-STF +T L-LTF +T L-SIG +T RL-SIG +T U-SIG +(T EHT-SIG-A )+(T EHT-SIG-B )+T EHT-STF +N EHT-LTF ·T EHT-LTF +T DATA

[0121] Referring to the above equation, the length of the PPDU is calculated based on the rounded-up value of L_LENGTH / 3. Therefore, for random values ​​of k, three different values ​​of L_LENGTH={3k+1, 3k+2, 3(k+1)} indicate the same PPDU length.

[0122] Reference Figure 7 (e), the Universal SIG (U-SIG) field continues to exist in subsequent generations of EHT PPDU and wireless LAN PPDU, and is used to classify the generation of PPDU including 11be. U-SIG is an OFDM 2 symbol based on 64FFT and can transmit a total of 52 bits of information. Of the 52 bits, 43 bits except the 9 bits of CRC / tail are mainly divided into a Version Independent (VI) field and a Version Dependent (VD) field.

[0123] The VI bit enables the current bit configuration to be maintained later, so that even if the next generation of PPDU is defined, the current 11be terminal can obtain information about the PPDU through the VI field of the PPDU. To this end, the VI field includes PHY version, UL / DL, BSS color, TXOP, and reserved fields. The PHY version field is 3 bits and is used to sequentially classify 11be and subsequent generations of wireless LAN standards into versions. The value of 11be is 000b. The UL / DL field identifies whether the PPDU is an uplink / downlink PPDU. The BSS color indicates the identifier of each BSS defined in 11ax and has a value of 6 bits or higher. TXOP indicates the transmission opportunity duration (Transmit Opportunity Duration) transmitted in the MAC header, where, by adding TXOP to the PHY header, the PPDU can infer the length of the TXOP included therein without having to decode the MPDU, and TXOP has a value of 7 bits or higher.

[0124] The VD field is signaling information useful only for the 11be version of the PPDU, and may include fields commonly used in any PPDU format such as PPDU format and BW, and fields defined differently for each PPDU format. The PPDU format is a classifier for classifying EHT Single User (SU), EHT Multiple User (MU), EHT Trigger-based (TB), EHT Extended Range (ER) PPDU, etc. The BW field signals five basic PPDU BW options (BW, which can be expressed in the type of 20*2 exponential power, which can be referred to as basic BW) of 20, 40, 80, 160 (80+80) and 320 (160+160) MHz, and various remaining PPDU BWs configured via preamble puncturing. After signaling at 320MHz, signaling can be performed in the type of some 80MHz puncturing. The punctured and modified channel type may be signaled directly in the BW field, or the punctured and modified channel type may be signaled using the BW field and a field that appears after the BW field (e.g., a field within the EHT-SIG field). If the BW field is configured as 3 bits, a total of 8 BW signalings may be performed, and thus only up to 3 signalings may be performed in the puncturing mode. If the BW field is configured as 4 bits, a total of 16 BW signalings may be performed, and thus up to 11 signalings may be performed in the puncturing mode.

[0125] The field located after the BW field varies depending on the type and format of the PPDU, the MU PPDU and the SU PPDU may be signaled in the same PPDU format, a field for classifying between the MU PPDU and the SU PPDU may be located before the EHT-SIG field, and additional signaling may be performed on the field. Both the SU PPDU and the MU PPDU include the EHT-SIG field, but some fields that are not required in the SU PPDU may be compressed. Information about the field to which compression has been applied may be omitted or may have a size smaller than the size of the original field included in the MU PPDU. For example, in the case of the SU PPDU, the common field of the EHT-SIG may be omitted or replaced, or the SU PPDU may have a different configuration in which a user-specific field is replaced, reduced to one, etc.

[0126] Alternatively, the SU PPDU may further include a compression field indicating whether compression is performed, and a portion of a field (eg, RA field, etc.) may be omitted according to a value of the compression field.

[0127] If a portion of the EHT-SIG field of the SU PPDU is compressed, the information to be included in the compressed field may also be signaled in an uncompressed field (e.g., a common field, etc.). The MU PPDU corresponds to a PPDU format for simultaneous reception by multiple users, and therefore requires the EHT-SIG field to be transmitted after the U-SIG field, and the amount of information transmitted may vary. That is, multiple MU PPDUs are transmitted to multiple STAs, so that each STA should identify the position of the RU to which the MU PPDU is transmitted, the STA to which the RU is respectively allocated, and whether the transmitted MU PPDU has been transmitted to the STA itself. Therefore, the AP should transmit the above information by including it in the EHT-SIG field. To this end, information for effective transmission of the EHT-SIG field is signaled in the U-SIG field, and this may correspond to the MCS as a modulation method and / or the number of symbols in the EHT-SIG field. The EHT-SIG field may include information about the size and position of the RU allocated to each user.

[0128] In the case of a SU PPDU, multiple RUs may be allocated to a STA, and the multiple RUs may be contiguous or discontinuous. If the RUs allocated to the STA are discontinuous, the STA should identify the punctured RUs in the middle in order to effectively receive the SUPPDU. Therefore, the AP may transmit a SU PPDU including information of the punctured RUs among the RUs allocated to the STA (e.g., the puncturing pattern of the RUs, etc.). That is, in the case of a SU PPDU, a puncturing pattern field may be included in the EHT-SIG field, the puncturing pattern field including information indicating the puncturing pattern and whether the puncturing pattern is applied in a bitmap format, etc., and the puncturing pattern field may signal the type of discontinuous channels occurring within the bandwidth.

[0129] The signaled discontinuous channel type is limited and indicates the BW and discontinuous channel information of the SU PPDU combined with the value of the BW field. For example, the SU PPDU is a PPDU transmitted only to a single terminal, so that the STA can identify the bandwidth allocated to itself via the BW field contained in the PPDU, and the SU PPDU can identify the puncturing resources in the allocated bandwidth via the puncturing mode field of the EHT-SIG field or the U-SIG field contained in the PPDU. In this case, the terminal can receive the PPDU in the remaining resource units after excluding the special channels of the punctured resource units. Multiple RUs allocated to the STA can be configured by different frequency bands or tones.

[0130] In order to reduce the signaling overhead of the SU PPDU, only limited discontinuous channel types are signaled. Puncturing can be performed for each 20MHz subchannel, so if puncturing is performed for a BW with a large number of 20MHz subchannels (such as 80, 160, and 320MHz), in the case of 320MHz, the discontinuous channel type (if puncturing only for the edge 20MHz is also considered discontinuous) should be signaled by indicating whether each of the remaining 15 20MHz subchannels after excluding the primary channel is used. In this way, considering the low transmission rate of the signaling part, allocating 15 bits to signal the discontinuous channel type of a single user transmission may act as an excessive signaling overhead.

[0131] The present invention proposes a technique for signaling a discontinuous channel type of a SU PPDU and shows the discontinuous channel type determined according to the proposed technique. The present invention also proposes a technique for signaling each of the puncturing types of the primary 160 MHz and the secondary 160 MHz in the 320 MHz BW configuration of the SU PPDU.

[0132] In addition, a technique for configuring a PPDU indicated by a leading puncturing BW value differently according to a PPDU format signaled in a PPDU format field is proposed in an embodiment of the present invention. Assuming that the BW field is 4 bits, and in the case of an EHT SU PPDU or a TB PPDU, an EHT-SIG-A of 1 symbol may be additionally signaled after the U-SIG, or the EHT-SIG-A may not be signaled at all, therefore, in view of this, it is necessary to fully signal up to 11 puncturing patterns only via the BW field of the U-SIG. However, in the case of an EHT MU PPDU, an EHT-SIG-B is additionally signaled after the U-SIG, so that up to 11 puncturing patterns may be signaled in a method different from that of the SU PPDU. In the case of an EHT ER PPDU, the BW field may be configured as 1 bit to signal whether the EHT ER PPDU is a PPDU using a 20 MHz band or a 10 MHz band.

[0133] Figure 7 (f) shows the configuration of the format-specific field of the VD field when the EHT MU PPDU is indicated in the PPDU format field of the U-SIG. In the case of the MU PPDU, SIG-B is necessarily required, which is a signaling field for simultaneous reception by multiple users, and SIG-B can be transmitted after the U-SIG without a separate SIG-A. To this end, information for decoding SIG-B should be signaled in the U-SIG. These fields include SIG-B MCS, SIG-BDCM, the number of SIG-B symbols, SIG-B compression, and the number of EHT-LTF symbols, etc.

[0134] Figure 8 Examples of various extremely high throughput (EHT) physical protocol data unit (PPDU) formats and a method for indicating the formats according to an embodiment of the present invention are shown.

[0135] Reference Figure 8 , the PPDU may include a preamble and a data part, and the EHT PPDU format as the PPDU type may be classified according to the U-SIG field included in the preamble. Specifically, based on the PPDU format field included in the U-SIG field, it may be indicated whether the format of the PPDU is an EHT PPDU.

[0136] Figure 8(a) shows an example of an EHT SU PPDU format for a single STA. The EHT SU PPDU is a PPDU for single user (SU) transmission between an AP and a single STA, and an EHT-SIG-A field for additional signaling may be located after the U-SIG field.

[0137] Figure 8 (b) shows an example of an EHT triggered PPDU format corresponding to an EHT PPDU transmitted based on a trigger frame. The EHT triggered PPDU is an EHT PPDU transmitted based on a trigger frame and is an uplink PPDU for responding to a trigger frame. Unlike the EHT SU PPDU, the EHT-SIG-A field is not located after the U-SIG field in the EHT PPDU.

[0138] Figure 8 (c) shows an example of an EHT MU PPDU format corresponding to an EHT PPDU of multiple users. The EHT MU PPDU is a PPDU for transmitting a PPDU to one or more STAs. In the EHT MU PPDU format, the HE-SIG-B field may be located after the U-SIG field.

[0139] Figure 8 (d) shows an example of an EHT ER SU PPDU format, which is used for single user transmission with STAs within extended range. Figure 8 Compared with the EHT SU PPDU illustrated in (a), the EHT ER SU PPDU can be used for single-user transmission with a wider range of STAs, and the U-SIG field can be repeatedly positioned on the time axis.

[0140] Figure 8 The EHT MU PPDU described in (c) may be used by the AP to perform downlink transmission toward multiple STAs. Here, the EHT MU PPDU may include scheduling information so that multiple STAs can simultaneously receive the PPDU transmitted from the AP. The EHT MU PPDU may transmit the AID information of the transmitter and / or receiver of the PPDU transmitted via the user specific field of the EHT-SIG-B to the STA. Therefore, multiple terminals that have received the EHT MU PPDU may perform a spatial reuse operation based on the AID information of the user specific field included in the preamble of the received PPDU.

[0141] Specifically, the resource unit allocation (RA) field of the HE-SIG-B field included in the HE MU PPDU may include information about the configuration of the resource unit in a special bandwidth (e.g., 20 MHz, etc.) of the frequency axis (e.g., the division type of the resource unit). That is, the RA field may indicate the configuration of the resource unit divided in the bandwidth used for transmission of the HE MU PPDU so that the STA receives the PPDU. Information about the STA allocated (or designated) to each divided resource unit may be included in the user special field of the EHT-SIG-B so as to be transmitted to the STA. That is, the user special field may include one or more user fields corresponding to the corresponding divided resource unit.

[0142] For example, a user field corresponding to at least one resource unit used for data transmission among multiple segmented resource units may include an AID of a receiver or a transmitter, and a user field corresponding to the remaining resource units not used for data transmission may include a pre-configured Null STA ID.

[0143] For convenience of explanation, frame or MAC frame may be used interchangeably with MPDU in this specification.

[0144] When a wireless communication device uses multiple links to communicate, the communication efficiency of the wireless communication device can be improved. At this time, the link is a physical path and can be composed of a single wireless medium that can be used to transmit a MAC service data unit (MSDU). For example, if the frequency band of one link is being used by another wireless communication device, the wireless communication device can continue to perform communication through another link. In this way, the wireless communication device can effectively use multiple channels. In addition, when the wireless communication device uses multiple links to perform communication simultaneously, the total throughput can be increased. However, in the existing wireless LAN, it is stipulated on the premise that one wireless communication device uses one link. Therefore, a wireless LAN operation method using multiple links is needed. Reference will be made to Figures 9 to 26 A wireless communication method for a wireless communication device using multiple links is described. First, reference will be made to Fig. 9 A specific form of wireless communication device using multiple links is described.

[0145] Fig. 9 A multi-link device according to an embodiment of the present invention is shown.

[0146] A multi-link device (MLD) may be defined for a wireless communication method using the above-mentioned multiple links. A multi-link device may refer to a device having one or more affiliated stations. According to a specific embodiment, a multi-link device may refer to a device having two or more affiliated stations. In addition, a multi-link device may exchange multi-link elements. A multi-link element includes information about one or more stations or one or more links. A multi-link element may include a multi-link setting element to be described later. At this time, a multi-link device may be a logical entity. Specifically, a multi-link device may have multiple affiliated stations. A multi-link device may be referred to as a multi-link logical entity (MLLE) or a multi-link entity (MLE). A multi-link device may have a media access control service access point (MAC SAP) up to a logical link control (LLC). In addition, an MLD may have a MAC data service.

[0147] The multiple stations included in the multi-link device can operate on multiple links. In addition, the multiple stations included in the multi-link device can operate on multiple channels. Specifically, the multiple stations included in the multi-link device can operate on multiple different links or multiple different channels. For example, the multiple stations included in the multi-link device can operate in multiple different channels of 2.4 GHz, 5 GHz and 6 GHz.

[0148] The operation of the multi-link device may be referred to as a multi-link operation, an MLD operation, or a multi-band operation. In addition, if the station attached to the multi-link device is an AP, the multi-link device may be referred to as an AP MLD. In addition, if the station attached to the multi-link device is a non-AP station, the multi-link device may be referred to as a non-AP MLD.

[0149] Fig. 9 The operation of non-AP MLD and AP MLD communication is shown. Specifically, non-AP MLD and AP MLD each use three links for communication. AP MLD includes a first AP AP1, a second AP AP2, and a third AP AP3. Non-AP MLD includes a first non-AP STA (non-AP STA1), a second non-AP STA (non-AP STA2), and a third non-AP STA (non-AP STA3). The first AP AP1 and the first non-AP STA (non-AP STA1) communicate through the first link link1. In addition, the second AP AP2 and the second non-AP STA (non-AP STA2) communicate through the second link link2. In addition, the third AP AP3 and the third non-AP STA (non-AP STA3) communicate through the third link link3.

[0150] The multilink operation may include a multilink setup operation. The multilink setup corresponds to the association operation of the above-mentioned single link operation, and may need to be performed preferentially for frame exchange in the multilink. The multilink device may obtain the information required for the multilink setup from the multilink setup element. Specifically, the multilink setup element may include capability information related to the multilink. At this time, the capability information may include information indicating whether the multiple devices included in the multilink device are capable of receiving while one device is transmitting. In addition, the capability information may include information about the links that can be used by each station included in the MLD. In addition, the capability information may include information about the channels that can be used by each station included in the MLD.

[0151] The multi-link setting can be set by negotiation between peer stations. Specifically, the multi-link setting can be performed by communication between stations without communicating with the AP. In addition, the multi-link setting can be set by any link. For example, even when the first link to the third link are set by multi-link, the multi-link setting can be performed by the first link.

[0152] In addition, a mapping between a traffic identifier (TID) and a link may be set. Specifically, a frame corresponding to a TID of a specific value may only be exchanged through a predetermined link. The mapping between the TID and the link may be set based on a direction. For example, when a plurality of links are set between a first multi-link device and a second multi-link device, the first multi-link device is configured to send a frame of a first TID on a first link among the plurality of links, and the second multi-link device may be configured to send a frame of a second TID on the first link. In addition, a default configuration may exist for the mapping between the TID and the link. Specifically, if no additional configuration is performed in the multi-link setting, the multi-link device may exchange frames corresponding to the TID on each link according to the default configuration. At this time, the default configuration may be to exchange all TIDs on one link.

[0153] TID will be described in detail. TID is an ID that classifies traffic and data to support QoS (Quality of Service). In addition, TID can be used or allocated in a layer higher than the MAC layer. In addition, TID can represent a traffic category (TC: traffic category) or a traffic stream (TS: traffic stream). In addition, TID can be divided into 16 types. For example, TID can be assigned to any one of 0 to 15. The TID value used can be assigned differently according to the access policy, channel access or media access method. For example, when enhanced distributed channel access (EDCA: enhanced distributed channel access) or hybrid coordination function contentionbased channel access (HCAF: hybrid coordination function contentionbased channel access) is used, the TID value can be assigned to 0 to 7. If EDCA is used, TID can represent user priority (UP: user priority). At this time, UP can be specified according to TC or TS. UP can be allocated by a layer higher than MAC. In addition, when HCF controlled channel access (HCCA: HCF controlled channel access) or SPCA is used, TID values ​​can be assigned to 8 to 15. If HCCA or SPCA is used, TID may represent TSID. In addition, when HEMM or SEMM is used, the value of TID may be allocated to 8 to 15. If HEMM or SEMM is used, TID may represent TSID.

[0154] UP can be mapped to AC. AC can be a label used to provide QoS in EDCA. AC can be a label used to indicate an EDCA parameter set. EDCA parameters or EDCA parameter sets are parameters used in channel contention in EDCA. QoS stations can use AC to guarantee QoS. In addition, AC may include AC_BK, AC_BE, AC_VI, and AC_VO. AC_BK, AC_BE, AC_VI, and AC_VO can represent background, best effort, video, and voice, respectively. In addition, AC_BK, AC_BE, AC_VI, and AC_VO can be classified as subordinate ACs. For example, AC_VI can be subdivided into primary AC_VI and standby AC_VI. In addition, AC_VO can be subdivided into primary AC_VO and standby AC_VO. In addition, UP or TID can be mapped to AC. For example, 1, 2, 0, 3, 4, 5, 6, and 7 of UP or TID can be mapped to AC_BK, AC_BK, AC_BE, AC_BE, AC_VI, AC_VI, AC_VO, and AC_VO, respectively. In addition, 1, 2, 0, 3, 4, 5, 6, and 7 of UP or TID can be mapped to AC_BK, AC_BK, AC_BE, AC_BE, spare AC_VI, main AC_VI, main AC_VO, and spare AC_VO, respectively. In addition, 1, 2, 0, 3, 4, 5, 6, and 7 of UP or TID can have higher priority in this order. That is, 1 can be a low priority, and 7 can be a high priority. Therefore, the priority can be increased in the order of AC_BK, AC_BE, AC_VI, and AC_VO. In addition, AC_BK, AC_BE, AC_VI, and AC_VO can correspond to ACI (AC index) 0, 1, 2, and 3, respectively. Due to these characteristics of TID, the mapping between TID and link can represent the mapping between AC and link. In addition, the mapping between link and AC can represent the mapping between TID and link.

[0155] As described above, a TID may be mapped to each of a plurality of links. The mapping may specify a link on which traffic corresponding to a particular TID or AC may be exchanged. In addition, a TID or AC that can be sent for each transmission direction within a link may be specified. As previously described, there may be a default configuration for the mapping between TIDs and links. Specifically, if no additional configuration is performed in the multi-link setting, the multi-link device may exchange frames corresponding to the TID on each link according to the default configuration. At this point, the default configuration may be to exchange all TIDs on one link. At any point in time, any TID or AC may be mapped to at least one link. Management frames and control frames may be transmitted on all links.

[0156] If a link is mapped to a TID or AC, only data frames corresponding to the TID or AC mapped to the link can be transmitted on the link. Therefore, if a link is mapped to a TID or AC, frames that do not correspond to the TID or AC mapped to the link cannot be transmitted on the link. If a link is mapped to a TID or AC, ACK can also be transmitted based on the link to which the TID or AC is mapped. For example, a block ACK agreement can be determined based on the mapping between the TID and the link. In another specific embodiment, the mapping between the TID and the link can be determined based on the block ACK agreement. Specifically, a block ACK agreement can be set for a TID mapped to a specific link.

[0157] Through the mapping between the TID and the link, QoS can be guaranteed. Specifically, a high-priority AC or TID can be mapped to a link operated by a relatively small number of stations or with good channel conditions. In addition, through the mapping between the TID and the link, the station can stay in a sleep state for more time.

[0158] Fig.10 It shows multiple links mapped by the TID-to-link mapping method according to an embodiment of the present invention.

[0159] Reference Fig.10 , as referenced Fig. 9 As described above, there may be a mapping relationship between a TID and a link. In addition, in the present invention, the mapping relationship between a TID and a link may be referred to as a TID-to-link mapping, a TID to link mapping, a TID mapping, a link mapping, etc. The TID may be a traffic identifier. In addition, the TID may be an identifier (ID) for classifying traffic, data, etc. to support quality of service (QoS).

[0160] In addition, TID may be an ID used or allocated in a layer higher than the MAC layer. TID may represent a traffic class (TC) and a traffic stream (TS). In addition, TID may be 16 values, for example, may be represented by values ​​from 0 to 15. In addition, different TID values ​​may be used according to access policies, channel access, and medium access methods. For example, when EDCA (Hybrid Cooperative Function (HCF) Contention-Based Channel Access, Enhanced Distributed Channel Access) is used, possible TID values ​​may be 0 to 7. In addition, in the case of using EDCA, the TID value may indicate a user priority (UP), and the UP may be a value about TC or TS. In addition, UP may be a value allocated in a layer higher than MAC. In addition, when HCCA (HCF Controlled Channel Access) or SPCA is used, possible TID values ​​may be 8 to 15. In addition, when HCCA or SPCA is used, TID may indicate TSID. In addition, when HEMM or SEMM is used, TID values ​​may be 8 to 15. In addition, when HEMM or SEMM is used, TID may represent TSID.

[0161] In addition, there may be a mapping relationship between UP and access category (AC). AC may be a label indicating a label for providing QoS in EDCA, or a label indicating a set of EDCA parameters. EDCA parameters or a set of EDCA parameters may be used for channel access. AC may be used by QoS STA.

[0162] The AC value may be set to one of AC_BK, AC_BE, AC_VI, and AC_VO. AC_BK, AC_BE, AC_VI, and AC_VO may represent background, best effort, video, and voice, respectively. In addition, AC_BK, AC_BE, AC_VI, and AC_VO may be subdivided. For example, AC_VI may be subdivided into main AC_VI and spare AC_VI. In addition, AC_VO may be subdivided into main AC_VO and spare AC_VO. In addition, UP values ​​or TID values ​​may be mapped to AC values. For example, UP values ​​or TID values ​​1, 2, 0, 3, 4, 5, 6, and 7 may be mapped to AC_BK, AC_BK, AC_BE, AC_BE, AC_VI, AC_VI, AC_VO, and AC_VO, respectively. Alternatively, UP values ​​or TID values ​​1, 2, 0, 3, 4, 5, 6, 7 may be mapped to AC_BK, AC_BK, AC_BE, AC_BE, spare AC_VI, main AC_VI, main AC_VO, spare AC_VO, respectively. In addition, UP values ​​or TID values ​​1, 2, 0, 3, 4, 5, 6, and 7 may have priorities that become higher in order. That is, "1" may be a low priority, and "7" may be a high priority. Therefore, the priority may increase in the order of AC_BK, AC_BE, AC_VI, and AC_VO. In addition, AC_BK, AC_BE, AC_VI, and AC_VO may correspond to AC indexes (ACI) 0, 1, 2, and 3, respectively.

[0163] Therefore, there may be a relationship between TID and AC. Therefore, the TID-to-link mapping of the present invention may also be a mapping relationship between AC and link. In addition, in the present invention, "TID is mapped" may mean that AC is mapped, and vice versa.

[0164] According to an embodiment of the present invention, there may be a TID mapped to each link in the multi-link. For example, there may be a mapping about which link in the multiple links a specific TID or a specific AC is allowed to send and receive on. In addition, such a mapping may be defined for each of the two directions of the link. In addition, as described above, the mapping between the TID and the link may have a default configuration. For example, the mapping between the TID and the link may be that basically all TIDs are mapped to a certain link. In addition, according to an embodiment, at a specific time point, a certain TID or a certain AC may be mapped to at least one link. In addition, management frames or control frames may be sent on all links.

[0165] In the present invention, a data frame corresponding to a TID or AC mapped for a specific direction of a link can be transmitted. In addition, a data frame corresponding to a TID or AC not mapped for a specific direction of a link cannot be transmitted.

[0166] According to an embodiment, TID-to-link mapping may also be applied to acknowledgement. For example, a block ack agreement may be based on TID-to-link mapping. Alternatively, TID-to-link mapping may be based on a block ack agreement. For example, there may be a block ack agreement for TIDs mapped by TID-to-link.

[0167] QoS services can be provided through TID-to-link mapping. For example, by mapping ACs and TIDs with high priority to links with good channel status or fewer STAs, data of the corresponding ACs and TIDs can be quickly sent. Alternatively, through TID-to-link mapping, STAs on a specific link can achieve power save (or can enter a doze state).

[0168] Reference Fig.10 , there may be an AP MLD including AP1 and AP2. In addition, there may be a non-AP MLD including STA 1 and STA 2. In addition, Link 1 and Link 2 as multiple links may exist in the AP MLD. AP1 and STA 1 may be associated in Link 1, and AP2 and STA 2 may be associated in Link 2.

[0169] Therefore, link 1 may include a link sent from AP1 to STA 1 and / or a link sent from STA 1 to AP1, and link 2 may include a link sent from AP2 to STA 2 and / or a link sent from STA 2 to AP2. In this case, TID and / or AC may be mapped to each link.

[0170] For example, all TIDs and all ACs may be mapped to a link in link 1 sent from AP1 to STA 1 and a link in link 1 sent from STA 1 to AP1. In addition, only AC_VO or a TID corresponding to AC_VO may be mapped to a link in link 2 sent from STA 2 to AP2. In addition, only data of the mapped TIDs and / or ACs may be sent through the corresponding links. In addition, data of the TIDs or ACs that are not mapped to the links cannot be sent on the corresponding links.

[0171] Fig.11 is a diagram showing an example of a multi-link NAV setting operation according to an embodiment of the present invention.

[0172] A simultaneous transmit and receive (STR) operation in which the MLD transmits or receives simultaneously may be limited and associated with a frequency spacing between multiple links operated through the multi-link.

[0173] Therefore, according to the embodiment of the present invention, when the interval between the links is m MHz, simultaneous transmission or reception is limited, and when the interval between the links is n MHz (n is greater than m), simultaneous transmission or reception may be unlimited. This embodiment can solve the limitation problem of simultaneous transmission or reception, and repeated description can be omitted. In addition, this embodiment can be applied to MLD that cannot STR.

[0174] According to an embodiment of the present invention, duration information may be shared between links operated through multiple links. Duration information may be TXOP duration information sent in a signaling field of a preamble. The signaling field may be the above-mentioned U-SIG field. Alternatively, the signaling field may be the above-mentioned HE-SIG-A field. In another embodiment, the duration information may be duration information indicated by a Duration / ID field included in a MAC header. In another embodiment, the duration information may be duration information indicated by a length field (LLength field) included in an L-SIG field. According to one embodiment, the duration information indicated by a U-SIG field, a HE-SIG-A field, or a Duration / ID field may be a value indicating a TXOP duration. According to one embodiment, the duration information indicated by the L-SIG field may be a value indicating the length of a physical layer protocol data unit (PPDU) including an L-SIG field or indicating the end of a PPDU including an L-SIG field.

[0175] In addition, according to an embodiment of the present invention, transmission or channel access may be limited to a duration based on duration information shared between links. The method of limiting transmission or channel access may include setting a NAV. Alternatively, the NAV may be reset to restore transmission or channel access. At this time, the NAV may be an intra-BSS NAV. The intra-BSS NAV may be a NAV set by a frame (or PPDU) within the BSS. That is, a STA attached to the MLD may set the NAV based on a frame (or PPDU) pointing to another STA attached to the MLD.

[0176] According to an embodiment of the present invention, an inter-link NAV may exist. In the case of multi-link operation, the inter-link NAV may be a NAV used by STAs of multiple links affiliated to a specific MLD. For example, based on the inter-link NAV set according to the duration information received in link 1, data may not be sent on link 2. In addition, the inter-link NAV may exist or be used for MLDs that cannot STR. For example, when the inter-link NAV is set, the MLD that sets the inter-link NAV may not perform transmission or channel access on multiple links (or all links used by the MLD).

[0177] In addition, in addition to the intra-BSS NAV, the type of NAV may also include a basic NAV. The basic NAV may be a NAV set by an inter-BSS frame (or PPDU), or may be a NAV set by a frame (or PPDU) that is not sure whether it is intra-BSS or inter-BSS.

[0178] Compared to the case where the inter-link NAV is not used, in the case where the inter-link NAV is additionally used, there may be an advantage in updating the NAV setting. For example, a situation may occur where it does not matter even if the NAV set by another link is reset. For example, although the inter-link NAV is set based on a specific frame (or PPDU), when it is determined that the above frame (or PPDU) is not directed to the same MLD, the set inter-link NAV may be reset. If there is an MLD operating in link 1 and link 2, the NAV of link 1 may be set based on the frame received in link 1. Thereafter, the NAV of link 1 may be updated based on the frame of link 2. In addition, if the NAV of link 1 is reset when there is no need to maintain the NAV of link 2, the NAV information set based on the frame received in link 1 may be lost. If the inter-link NAV is used together with the NAV of each link, the NAV of each link can be maintained even when the inter-link NAV is reset, so that this problem can be solved.

[0179] In the embodiment of the present invention, setting NAV is taken as an example for explanation, but the embodiment of the present invention is not limited thereto, but can be applied to the case where the physical layer is instructed to interrupt channel access or the channel state is busy. In addition, the present invention is not limited to the case where NAV is reset, but can also be applied to the case where the physical layer is instructed to continue channel access or the channel state is idle. In this case, primitives exchanged between the physical layer and the MAC layer can be used. Alternatively, primitives exchanged between one STA and another STA of the MLD can be used. Alternatively, primitives exchanged between one MAC layer and another MAC layer of the MLD can be used.

[0180] According to an embodiment of the present invention, when an STA attached to an MLD starts receiving a PPDU, another STA attached to the MLD may stop channel access. As described above, channel access may be stopped based on the received duration information, but due to the time required for the location of the field including the duration information or decoding, etc., there may be time from the start of receiving the PPDU to the acquisition of the duration information. Therefore, if the channel is accessed and transmission starts during this time, the above-mentioned problem may occur. Therefore, according to an embodiment of the present invention, the STA of the MLD may stop channel access from the point in time when another STA of the MLD starts receiving. In addition, when it is determined that the frame received after another STA of the MLD starts receiving is not directed to another STA, channel access may be restarted.

[0181] Fig.12 is a diagram showing another example of a multi-link NAV setting operation according to another embodiment of the present invention.

[0182] Fig.12 Show Fig.11 The detailed description of the specific methods of the embodiments shown in FIG. 1 is not provided, and thus a repeated description will be omitted.

[0183] As described above, based on a frame or PPDU received by a STA attached to the MLD, another STA attached to the same MLD may stop or resume channel access or transmission. In the present invention, stopping channel access or transmission may include operations such as setting (updating) NAV, determining that the channel is busy, or stopping CCA. In addition, resuming channel access or transmission may include operations such as resetting NAV, canceling NAV setting, determining that the channel is idle, or performing CCA. In the following, such operations may be indicated as stopping and resuming channel access. In addition, in the following, STA 1 and STA 2 are attached to MLD, and STA 1 and STA 2 operate on link 1 and link 2, respectively. In addition, frames and PPDUs may be mixed. In addition, the NAV at this time may be such as Fig.11 Intra-BSS NAV or Inter-Link NAV as described in.

[0184] According to an embodiment of the present invention, when STA 1 starts receiving a frame, STA 2 may interrupt channel access. In addition, when STA 1 obtains duration information from L-SIG, STA 2 may continue the state of interrupting channel access. In this case, the state in which STA 2 interrupts channel access may be determined to be until the end of the frame received by STA 1. In addition, when STA 1 does not correctly decode L-SIG (i.e., invalid L-SIG), STA 2 may resume channel access.

[0185] In addition, STA 1 may receive the TXOP duration and BSS color from the U-SIG of the received frame. If the received BSS color is within the BSS, or the BSS color is the BSS color corresponding to STA 1, the channel access may be interrupted. In one embodiment, the time period for interrupting the channel access at this time may be until the end of the received frame. In this case, after the end of the received frame, the channel access may be started more quickly. In another embodiment, the duration of interrupting the channel access may be the TXOP duration. In this case, the duration of the interrupted channel access may be updated based on the L-SIG. In this case, the subsequent sequence after the received frame may be better protected.

[0186] Alternatively, there may be a case where STA 1 may receive the TXOP duration and the BSS color from the U-SIG of the received frame, and the received BSS color may indicate that it is not within the BSS, or the BSS color is not the BSS color corresponding to STA 1. Alternatively, there may be a case where STA 1 fails to successfully decode the U-SIG. In this case, STA 2 may resume channel access.

[0187] Alternatively, if the information obtained from the U-SIG of the frame received by STA 1 indicates that the corresponding frame is a frame not received by STA 1, STA 2 can restore the channel access. For example, if the PHY identifier obtained from the U-SIG is an ID corresponding to a future standard or an ID that cannot be recognized, STA 2 can restore the channel access.

[0188] In addition, although the case of receiving U-SIG has been described, the same embodiment can also be applied to the case of receiving HE-SIG-A when receiving HE PPDU. For example, HE-SIG-A may include TXOP duration and BSS color, so the above operation can be performed.

[0189] In addition, the STA-ID may be received from the EHT-SIG of the frame received by STA 1. If the received STA-ID is an indicator that should be received by STA 1, for example, if the STA-ID indicates STA 1, the STA-ID indicates a group to which STA 1 belongs, or the STA-ID indicates broadcasting, STA 2 may maintain a state in which channel access is interrupted.

[0190] Alternatively, the STA-ID may be received from the EHT-SIG of the frame received by STA 1. If the received STA-ID is an indicator that does not correspond to STA 1, for example, if the STA-ID does not indicate an indicator corresponding to STA 1, the STA-ID does not indicate a group to which STA 1 belongs, and the STA-ID does not indicate broadcasting, STA 2 may resume channel access. Alternatively, even if STA 1 does not successfully decode the EHT-SIG, STA 2 may resume channel access.

[0191] In addition, although the case of receiving EHT-SIG has been described, the same embodiment can also be applied to the case of receiving HE-SIG-B in the case of receiving HEPPDU. For example, HE-SIG-B may include STA-ID, and thus the operation described above may be performed.

[0192] In addition, STA 1 may receive a MAC header of a frame to be received. If a reception address (RA) or a destination address (DA) included in the received MAC header indicates a value that STA 1 should receive, for example, if RA or DA indicates a group to which STA 1 belongs or STA-ID indicates broadcast, STA 2 may maintain the interrupted state of channel access. In this case, the channel duration may be determined based on duration information included in the received MAC header. More specifically, the duration of the interrupted channel access may be based on duration information indicated by a Duration / ID field included in the received MAC header.

[0193] In addition, STA 1 may receive a MAC header of a frame to be received. If RA or DA included in the received MAC header is an indicator that does not correspond to STA 1, for example, if RA or DA does not indicate an indicator corresponding to STA 1, does not indicate a group to which STA 1 belongs, and does not indicate broadcast, STA 2 may resume channel access. Alternatively, STA 1 may not have received all MAC headers. For example, STA 1 may not have successfully received all MPDUs included in the A-MPDU. In this case, STA 2 may resume channel access.

[0194] exist Fig.12The channel access interruption and recovery described in the above may be performed sequentially according to the decoding order as STA 1 starts receiving frames (or PPDUs) and decoding is performed sequentially. The decoding order may be based on the PPDU format, the frame format, etc. For example, decoding may be performed in the order of L-SIG, U-SIG, EHT-SIG, and MAC header (in the case of EHT PPDU). Alternatively, decoding may be performed in the order of L-SIG, HE-SIG-A, and MAC header (in the case of HE SU PPDU and HE TB PPDU). Alternatively, decoding may be performed in the order of L-SIG, HE-SIG-A, HE-SIG-B, and MAC header (in the case of HE MU PPDU). Alternatively, decoding may be performed in the order of L-SIG and MAC header (in the case of 11a / g PPDU).

[0195] According to an embodiment of the present invention, the above-mentioned STA-ID may be a value indicating the desired recipient of the PPDU or resource unit (RU). In addition, the STA-ID may be included in the EHT-SIG field or the HE-SIG-B field. In addition, the STA-ID may indicate a value corresponding to a single STA. For example, when multiple STAs are included in the MLD, the STA-ID may indicate a value corresponding to one STA among the multiple STAs. In addition, the STA-ID may be a value based on the AID or MAC address of the STA.

[0196] Fig.13 is a diagram showing an example of BSS classification and an operation based on the BSS classification according to an embodiment of the present invention.

[0197] According to an embodiment of the present invention, the STA may classify (or judge) the BSS based on the received frame or the received PPDU. The classification of the BSS may include classification according to whether the received frame or the received PPDU corresponds to the BSS to which the classified STA is attached. Alternatively, the classification of the BSS may refer to the operation of classifying according to whether the received frame or the received PPDU is sent from the BSS to which the classified STA is attached. In addition, the classification of the BSS may include the operation of classifying according to whether the received frame or the received PPDU is sent from the BSS to which the classified STA is not attached. In addition, the classification of the BSS may include the operation of classifying according to which BSS the received frame or the received PPDU is attached. Alternatively, the classification of the BSS may represent the operation of classifying according to which BSS the received frame or the received PPDU is sent from. According to an embodiment of the present invention, the BSS to which the classified STA is attached may be referred to as intra-BSS. Alternatively, the BSS including the BSS to which the classified STA is attached may be referred to as intra-BSS. In addition, a BSS that is not intra-BSS may be referred to as inter-BSS. Alternatively, a BSS that is not an intra-BSS may be an inter-BSS or an unclassified BSS. Alternatively, an inter-BSS may include an unclassified BSS. In addition, a BSS to which a classified STA is not affiliated may be referred to as an inter-BSS.

[0198] According to an embodiment of the present invention, when it is determined that the received frame or the received PPDU corresponds to or is sent from within the BSS, the received frame or the received PPDU may be referred to as an intra-BSS frame or an intra-BSS PPDU, respectively. In addition, when it is determined that the received frame or the received PPDU corresponds to or is sent from between BSSs, the received frame or the received PPDU may be referred to as an inter-BSS frame or an inter-BSS PPDU, respectively. In addition, a PPDU including an intra-BSS frame may be an intra-BSS PPDU. In addition, a PPDU including an inter-BSS frame may be an inter-BSS PPDU.

[0199] According to an embodiment of the present invention, the BSS may be classified based on one or more BSS classification conditions. For example, the BSS may be classified according to whether at least one of the one or more BSS classification conditions is satisfied.

[0200] The BSS classification condition may include a condition based on the BSS color. The BSS color may be an identifier of the BSS. In addition, the BSS color may be included in the preamble of the PPDU, more specifically, in a signaling field (e.g., a HE-SIG-A field, a U-SIG field, or a VHT-SIG-A field). In addition, the BSS color may be included in the TXVECTOR transmitted from the MAC layer of the sender to the PHY layer. In addition, the BSS color may be included in the RXVECTOR transmitted from the PHY layer of the receiver to the MAC layer. The parameters included in the TXVECTOR and the RXVECTOR may be referred to as TXVECTOR parameters and RXVECTOR parameters, respectively. In addition, the BSS color may be included in the TXVECTOR parameter or the RXVECTOR parameter. In addition, the AP may notify the STA of the BSS color set by the AP. According to an embodiment, the BSS may be classified based on the BSS color included in the received PPDU. If the BSS color included in the PPDU received by the STA is different from the BSS color of the BSS corresponding to the STA, the received PPDU may be classified as an inter-BSS PPDU. Alternatively, if the BSS color included in the PPDU received by the STA is different from the BSS color of the BSS corresponding to the STA and its value is not zero, the received PPDU can be classified as an inter-BSS PPDU. In addition, if the BSS color included in the PPDU received by the STA is the same as the BSS color of the BSS corresponding to the STA, the received PPDU can be classified as an intra-BSS PPDU.

[0201] The BSS classification condition may include a condition based on a MAC address. The MAC address may be included in a MAC header of a frame. In addition, the MAC address may include a receiver address (RA), a transmitter address (TA), a BSSID, a source address (SA), a destination address (DA), and the like. According to an embodiment, the BSS may be classified based on the MAC address included in the received frame. If the MAC address included in the received frame is different from the BSSID of the BSS corresponding to the STA, the received frame may be classified as an inter-BSS PPDU. More specifically, if all MAC addresses included in the received frame are different from the BSSID of the BSS corresponding to the STA, the received frame may be classified as an inter-BSS PPDU. In addition, if the MAC address included in the received frame is the same as the BSSID of the BSS corresponding to the STA, the received frame may be classified as an intra-BSS frame. More specifically, if at least one of the MAC addresses included in the received frame is the same as the BSSID of the BSS corresponding to the STA, the received frame may be classified as an intra-BSS frame.

[0202] The above-mentioned corresponding BSS may include the BSS associated with the STA. In addition, the corresponding BSS may include a BSS included in the same multi-BSSID set as the BSS associated with the STA. In addition, the corresponding BSS may include a BSS included in the same co-hosted BSSID set as the BSS associated with the STA. In addition, information about one or more BSSs included in the same multi-BSSID set or the same co-hosted BSSID set may be transmitted through one frame.

[0203] The BSS classification condition may include a condition based on the value of the partial AID field included in the VHT PPDU. The partial AID field may be included in the preamble of the VHT PPDU. In addition, the partial AID field may be included in the VHT-SIG-A field included in the VHT PPDU. According to an embodiment of the present invention, the partial AID field may represent a portion of the BSS color. For example, when the partial BSS color function is used, the partial AID field may indicate a portion of the BSS color. Alternatively, when the AID allocation rule is used, the partial AID field may indicate a portion of the BSS color. The AID allocation rule may be a method of allocating AIDs based on BSS colors. In addition, if the group ID field included in the VHT-SIG-A field of the VHT PPDU has a preset value (for example, the group ID field is set to 63), the partial AID field may indicate a portion of the BSS color. According to an embodiment, when the partial AID field of the received PPDU indicates a portion of the BSS color, if the value of the received partial AID field is different from a portion of the BSS color corresponding to the received STA, the received PPDU may be classified as an inter-BSS PPDU.

[0204] In addition, when the partial AID field of the received PPDU indicates a part of the BSS color, if the received partial AID field value is equal to a part of the BSS color corresponding to the received STA, the received PPDU may be classified as an intra-BSS PPDU. In addition, in this case, the part of the BSS color may be 4 LSBs of the BSS color. According to another embodiment, the partial AID field may indicate a part of the BSSID. For example, if the group ID field included in the VHT-SIG-A field of the VHT PPDU has a preset value (for example, the group ID field is set to 0), the partial AID field may indicate a part of the BSSID. According to an embodiment, when the partial AID field of the received PPDU indicates a part of the BSSID, if the received partial AID field value is different from a part of the BSSID corresponding to the received STA, the received PPDU may be classified as an inter-BSS PPDU. In addition, when the partial AID field of the received PPDU indicates a part of the BSSID, if the received partial AID field value is equal to a part of the BSSID corresponding to the received STA, the received PPDU may be classified as an intra-BSS PPDU. In addition, in this case, a portion of the BSSID may be the 9 MSBs of the BSSID. In addition, the Partial AID field value may be included in the TXVECTOR parameter PARTIAL_AID or the RXVECTOR parameter PARTIAL_AID. In addition, the Group ID field value may be included in the TXVECTOR parameter GROUP_ID or the RXVECTOR parameter GROUP_ID.

[0205] The BSS classification condition may include a condition for the AP to receive a PPDU that satisfies a predetermined condition. For example, the PPDU of the predetermined condition may include a downlink PPDU. According to an embodiment, the downlink PPDU may include a VHT MU PPDU. In addition, the downlink PPDU may include a PPDU in which the signaling indicating whether it is an uplink or a downlink is set to a preset value. The signaling indicating whether it is an uplink or a downlink may be included in the signaling field of the HE PPDU. Alternatively, the signaling indicating whether it is an uplink or a downlink may be included in the U-SIG. The U-SIG may be included in the preamble of the EHT PPDU or the PPDU after the EHT standard.

[0206] In addition, there may be cases where it cannot be classified as an intra-BSS PPDU or an inter-BSS PPDU. For example, if both the above-mentioned conditions for classification as an intra-BSS PPDU and the conditions for classification as an inter-BSS PPDU are not met, it may not be classified as an intra-BSS PPDU or an inter-BSS PPDU.

[0207] In addition, when the classification results according to multiple conditions are inconsistent when classifying the BSS, the final result can be determined according to a predetermined condition. For example, when the result according to the condition based on the BSS color is inconsistent with the result according to the condition based on the MAC address, the result according to the condition based on the MAC address can be given priority or the final result can be determined as the result according to the condition based on the MAC address. Alternatively, if both the condition for classification as an intra-BSS PPDU and the condition for classification as an inter-BSS PPDU are met, it can be classified as an intra-BSS PPDU.

[0208] According to an embodiment of the present invention, a STA may perform an operation based on a classified BSS. The operation based on the classified BSS may include a power saving operation within a PPDU. The power saving operation within a PPDU may be a power saving operation based on a received PPDU. When a predetermined condition is met, the power saving operation within the PPDU may be performed. The predetermined condition may include a condition for classifying the received PPDU as a PPDU within the BSS. In addition, the predetermined condition may include a condition in which the mandatory recipient of the received PPDU is not the STA that receives the PPDU. For example, if the ID or address included in the PPDU does not correspond to the STA that receives the PPDU, the mandatory recipient of the PPDU may not correspond to the STA that receives the PPDU. The ID may be included in the preamble of the PPDU. For example, the ID may be the STA_ID included in the preamble of the PPDU. In addition, the STA_ID may be included in the HE MU PPDU or the EHT PPDU. In addition, the address may be the above-mentioned MAC address. In addition, when the signaling indicating whether it is an uplink or a downlink included in the received PPDU indicates an uplink, the mandatory recipient of the PPDU may not be the STA that receives the PPDU. In addition, when the STA receiving the PPDU is configured not to support the configuration of the received PPDU, the mandatory recipient of the PPDU may not be the STA receiving the PPDU. The configuration of the received PPDU may include the MCS, the number of spatial streams, the channel width, etc. of the PPDU. In addition, if the STA receiving the PPDU does not support the configuration of the received PPDU, the PHY-RXEND.indication (UnsupportedRate) primitive may be received. In addition, if the received PPDU has a preset format, the mandatory recipient of the PPDU may not be the STA receiving the PPDU. The predetermined format may include a TB PPDU. The TB PPDU may include an HE TB PPDU and an EHT TB PPDU. In addition, the TB PPDU may be a PPDU sent in response to a triggered frame. The triggered frame may include a trigger frame. The triggered frame may include a frame containing trigger information. The trigger information may be included in a MAC header (e.g., an A-control field). In addition, the trigger information or the information included in the trigger frame may include the length of the response PPDU, the RU to be used in response, the PHY configuration to be used in response, the MAC configuration, etc. The power saving operation within the PPDU may be an operation of entering a doze state until the end of the received PPDU. In another embodiment, when the STA determines that the mandatory recipient of the received PPDU or frame is not the STA, the reception or decoding of the PPDU or frame may be interrupted.

[0209] The operation based on the classified BSS may include the operation of setting (or updating) NAV. According to one embodiment, the STA may operate one or more NAVs. In addition, when the STA receives a PPDU or a frame, the STA may set the NAV corresponding to the classified BSS based on the received PPDU or frame. For example, the intra-BSS NAV may be a NAV corresponding to the intra-BSS PPDU. In addition, the basic NAV may be a NAV corresponding to a PPDU other than the intra-BSS PPDU. Alternatively, the basic NAV may be a NAV corresponding to an inter-BSS PPDU. In addition, when the NAV is set based on the received PPDU or the received frame, the duration information included in the received PPDU or the received frame may be used. The duration information may include a TXOP. For example, the TXOP may indicate a value included in a TXOP field. The TXOP field may be included in the preamble of the PPDU. For example, the TXOP field may be included in the HE-SIG-A field of the HE PPDU. Alternatively, the TXOP field may be included in the U-SIG field of the EHT PPDU or the standard PPDU after the EHT. In addition, the duration information may be included in the MAC header. For example, the duration information may be included in a Duration / ID field included in a MAC header.

[0210] The operation of the classified BSS may include a spatial reuse operation. In addition, the operation of the classified BSS may include a channel access operation. The spatial reuse operation may be a channel access operation. When the STA receives a PPDU or a frame, if the preset condition is met, the STA may perform a spatial reuse operation. The preset condition may include a condition corresponding to the BSS between the received PPDU or the received frame. In addition, the preset condition may include a condition that the signal strength of the received PPDU or frame is less than a threshold. For example, the threshold may be variable. In addition, the threshold may be a threshold for a spatial reuse operation based on an OBSS PD. In addition, the threshold may be a value greater than or equal to a CCA threshold. In addition, the threshold may be a value based on the power to be transmitted. The spatial reuse operation may include an operation of sending a PPDU. In addition, the spatial reuse operation may include an operation of resetting the PHY. For example, the operation of resetting the PHY may be an operation of issuing a PHY-CCARESET.request primitive. In addition, the spatial reuse operation may include an operation of not setting the NAV based on the received PPDU or the received frame. If the STA performs a spatial reuse operation, the STA may send a PPDU during the transmission or reception of the received PPDU or frame.

[0211] Reference Fig.13, there may be BSS A and BSS B, and BSS A and BSS B may be different BSSs. In addition, BSS A and BSS B may correspond to each other as inter-BSSs. That is, a PPDU or frame transmitted in BSS B by a STA associated with BSS A may be classified as an inter-BSS PPDU or an inter-BSS frame. In addition, there may be STA 1 and STA 2 attached to BSS A (or associated with an AP running BSS A). There may be STA 3 and STA 4 attached to BSS B (or associated with an AP running BSS B). Fig.13 , STA 1 may send a PPDU. In addition, the PPDU sent by STA 1 may include information about the BSS. For example, the information about the BSS may be information for classifying the above-mentioned BSS. In addition, the PPDU sent by STA 1 may include duration information.

[0212] STA 2 may receive the PPDU transmitted by STA 1 and classify the BSS of the PPDU. In addition, since STA 2 and STA 1 are attached to BSS A, the PPDU received by STA 2 may be classified as an intra-BSS PPDU. In addition, the PPDU received by STA 2 may be a UL PPDU, or may be a PPDU whose mandatory recipient is not a STA. Therefore, according to the above-mentioned embodiment, STA 2 may perform intra-PPDU power saving. Referring to Fig.13 , STA 2 may enter the sleep state until the end time of the received PPDU. STA 2 may set the NAV based on the duration information included in the received PPDU. Since STA 2 classifies the received PPDU as an intra-BSS PPDU, STA 2 may set the intra-BSS NAV.

[0213] STA 3 may receive the PPDU transmitted from STA 1 and classify the BSS of the PPDU. In addition, since STA 3 and STA 1 are respectively attached to BSS B and BSS A, the PPDU received by STA 3 may be classified as an inter-BSS PPDU. In addition, STA 3 may set the NAV based on the duration information included in the received PPDU. Since STA 3 classifies the received PPDU as an inter-BSS PPDU, STA 3 may set the basic NAV.

[0214] STA 4 may receive a PPDU transmitted from STA 1 and classify the BSS of the PPDU. In addition, since STA 4 and STA 1 are respectively attached to BSS B and BSS A, the PPDU received by STA 4 may be classified as an inter-BSS PPDU. In addition, the signal strength of the PPDU received by STA 4 may be less than a threshold. Therefore, since the PPDU received by STA 4 is classified as an inter-BSS PPDU and the signal strength of the PPDU received by STA 4 is less than a threshold, STA 4 may perform a spatial reuse operation. Therefore, STA 4 may perform a channel access and backoff procedure and may start transmitting. For example, STA 4 may start transmitting at a time point when the PPDU transmitted by STA 1 has not yet ended.

[0215] Fig.14 A wireless LAN function according to an embodiment of the present invention is shown.

[0216] Reference Fig.14 , wireless LANs of certain standards may include the functions of wireless LANs of other standards. Or, in the case of wireless LANs of certain standards, they may also be wireless LANs of other standards. Here, wireless LAN may represent STA. In addition, the wireless LAN herein may represent MLD including STA. For example, the wireless LAN standard may include standard functions and additional functions of previous generations. For example, HT STA may be OFDM PHY STA. In addition, HT STA may perform the functions of OFDM PHY STA as well as additional functions. For example, VHT STA may also be HT STA. In addition, VHT STA may perform the functions of HT STA as well as additional functions. For example, HE STA may also be VHT STA. In addition, HE STA may perform the functions of VHT STA as well as additional functions. In addition, EHT STA may also be HE STA. In addition, EHT STA may perform the functions of HE STA as well as additional functions. In addition, there may be standards after the EHT standard. In the present invention, the standard after the EHT standard may be referred to as the NEXT standard, and the STA following the NEXT standard may be referred to as the NEXT STA. NEXT STA may also be the EHT STA. Furthermore, the NEXT STA can perform the functions of the EHT STA as well as additional functions.

[0217] Fig.14 is a diagram showing the relationship between STAs of each standard. Fig.14, the EHT STA may be a HE STA, a VHT STA, a HT STA, or an OFDM PHY STA. In addition, the NEXT STA may be an EHT STA, a HE STA, a VHT STA, a HT STA, or an OFDM PHY STA.

[0218] Fig.15 An uplink (UL) multi-user (MU) operation according to an embodiment of the present invention is shown.

[0219] Reference Fig.15 , the AP may instruct at least one STA to send a PPDU through a specific frame (eg, a trigger frame), and the at least one STA may simultaneously send PPDUs of the same or different formats based on the specific frame sent from the AP.

[0220] Specifically, Fig.15 As shown, a frame indicating (solicit) or triggering (trigger) multi-user (MU) transmission may be sent, and one or more STAs may send or respond to the frame. In this case, when one or more STAs send a response to the frame, one or more STAs may respond immediately (simultaneious) based on the frame, and start sending a response to the frame after SIFS at the end of the PPDU including the frame. For example, when the frame indicates an immediate response, one or more STAs may immediately send a response to the frame. The frame that instructs or triggers one or more STAs to transmit may be a trigger frame or a frame that includes information in the MAC header for indicating or triggering uplink transmission of one or more STAs. In this case, the frame may include information in the MAC header that triggers or indicates uplink transmission of only one STA (e.g., a TRS control subfield).

[0221] For example, the information indicating or triggering uplink transmission included in the MAC header may be a trigger response schedule (TRS) or a TRS control subfield included in an HT control field, a control subfield, or an A control subfield.

[0222] The frame for indicating or triggering uplink transmission can be sent by the AP, and when the frame for indicating or triggering uplink transmission is a trigger frame, a response thereto can be sent in a trigger-based PPDU (TB PPDU) format. In this case, the TB PPDU can include not only the above-mentioned HE TB PPDU and EHT TB PPDU, but also the NEXT TB PPDU defined in the next generation standard.

[0223] HE TB PPDU may include a preamble, data, and a packet extension (PE). The preamble may include L-STF, L-LTF, L-SIG, RL-SIG, HE-SIG-A, HE-STF, and HE-LTF in sequence.

[0224] The EHT TB PPDU and NEXT TB PPDU may also include a preamble, data, PE, etc. The preamble of the EHT TB PPDU and NEXTTB PPDU may include L-STF, L-LTF, L-SIG, RL-SIG, U-SIG, (EHT- / NEXT-)STF, and (EHT- / NEXT-)LTF in sequence.

[0225] A frame that instructs or triggers one or more STAs to send a PPDU may include information required for one or more STAs to send a TB PPDU. For example, when the type subfield included in the frame is "01" (B3 B2) and the subtype subfield is "0010" (B7B6 B5 B4), the frame including the type subfield and the subtype subfield may be a trigger frame as a control frame.

[0226] When multiple STAs are instructed or triggered to respond to a TB PPDU, if the formats of the PPDUs to which the multiple STAs respond are different from each other, a problem may occur that it is difficult for the AP that instructs or triggers the response to receive the PPDUs as responses sent from the multiple STAs. Alternatively, if the information included in the preamble of the PPDUs to which the multiple STAs respond is different according to the format, a problem may occur that it is difficult for the AP that instructs or triggers the response to receive the PPDUs as responses sent from the multiple STAs.

[0227] Therefore, in order to solve this problem, when multiple STAs respond to the frame of the AP, the format of the responded PPDU and / or the type of information included in the preamble of the PPDU can be set to be the same. For example, when multiple STAs send HETB PPDUs in response to the frame of the AP, the AP can send information so that the information included in L-STF, L-LTF, L-SIG, RL-SIG and HE-SIG-A are the same, or the information included in the HE TB PPDU can be agreed upon so that the AP can successfully receive the preambles sent by multiple STAs. However, if the HE TB PPDU, the EHT TB PPDU and the NEXT TB PPDU are simultaneously transmitted through overlapping subbands, it may be difficult for the AP to receive them because the TB PPDU formats are different from each other.

[0228] According to an embodiment of the present invention, HE STA may send HE TB PPDU. In addition, EHT STA may send EHT TB PPDU or HE TB PPDU. In addition, NEXT STA may send NEXT TB PPDU, EHT TB PPDU or HE TB PPDU. This is because as shown in FIG. Fig.10 As mentioned above, STA of certain standards may include the functions of previous standards.

[0229] like Fig.15 As shown in the figure, when the AP sends a frame for scheduling the transmission of a TB PPDU to the HE STA and the EHT STA, and indicates or triggers the transmission of the TB PPDU through the frame, there may not be an accurate indication or protocol for the TB PPDU format. In this case, the HE STA may send the HE TB PPDU in response to the frame, and the EHT STA may respond with the EHT TB PPDU or the HE TB PPDU. In this case, it may be difficult for the AP to receive the TB PPDU sent by the STA, and the following problem may also occur, that is, the AP fails to successfully receive the TB PPDU from multiple STAs and fails to achieve successful transmission, but the medium is occupied, so the transmission opportunities of other STAs are reduced.

[0230] Hereinafter, in the present invention, "instructing the STA" may mean "instructing the STA to respond", and triggering and instructing may have the same meaning.

[0231] In addition, the HE trigger frame, the EHT trigger frame, and the NEXT trigger frame may be trigger frames defined in the HE, EHT, and NEXT standards. In addition, in the present invention, the HE TRS, the EHT TRS, and the NEXT TRS may be TRSs defined in the HE, EHT, and NEXT standards.

[0232] Fig.16 The trigger frame format according to an embodiment of the present invention is shown.

[0233] Fig.16 (a) shows the trigger frame format, Fig.16 (b) and Fig.16 (c) respectively show the common information field and the user information field included in the trigger frame.

[0234] Reference Fig.16 (a), as a trigger MAC header, the frame includes a frame control field, a duration field, and an address field, and may include a common information field and a user information list field. The address field may include a resource allocation (RA) field and a transmission address (TA) field.

[0235] The common information field may include information common to all STAs indicated by the trigger frame. Fig.16 (b) shows an example of the public information field.

[0236] The user information list field may include 0 or more user information fields, and the user information list field of a trigger frame other than a specific type of a trigger frame may include one or more user information fields. Fig.16 (c) shows an example of a user information field.

[0237] The trigger frame may also include a padding field and a frame check sequence (FCS) field. The padding field may be used to increase the length of the frame to ensure the time required for the STA receiving the trigger frame to prepare a response to the trigger frame, and may be selectively included in the trigger frame.

[0238] Reference Fig.16 (b) The common information field may include a trigger type subfield. The trigger type subfield may be used to identify a trigger frame variant. Alternatively, the type of trigger frame may be indicated based on the value of the trigger frame subfield. In addition, based on the trigger type subfield, it may be determined whether the trigger frame is included in the trigger frame variant. Fig.12 The information and length in the Trigger Dependent Common Info subfield and the Trigger Dependent User Info subfield are shown. For example, the Trigger Type subfield can be represented by bits B0 to B3 of the Common Info field.

[0239] The common information field may include an uplink (UL) length subfield. The UL length subfield may include information about the length of the TB PPDU as a response to the trigger frame, and may include information about the length of the frame responding to the trigger frame. In addition, the UL length subfield may indicate a value included in the length subfield of the L-SIG of the TB PPDU responding to the trigger frame. Therefore, the STA that receives the trigger frame and responds with the TB PPDU may set the value of the length subfield included in the L-SIG of the TB PPDU based on the value of the UL length subfield included in the received trigger frame. Specifically, the STA that responds with the TB PPDU may set the length subfield included in the L-SIG of the TB PPDU to the value of the UL length subfield included in the received trigger frame. For example, the STA may set the length subfield included in the L-SIG of the TB PPDU based on the values ​​B4 to B15 of the common information field indicating the UL length subfield, and send the TB PPDU.

[0240] In addition, the common information field may further include a UL bandwidth (BW) subfield. The UL BW subfield may indicate a BW value included in a signaling field (e.g., HE-SIG-A or U-SIG, etc.) of a TB PPDU in response to a trigger frame, and may indicate a maximum BW of a TB PPDU sent in response to a trigger frame. Therefore, the STA may set a BW value included in a signaling field of a TB PPDU based on a value of a UL BW subfield included in a trigger frame.

[0241] In addition, the common information field may also include information included in the signaling field of the TB PPDU as a response to the trigger frame. Therefore, after receiving the trigger frame, the STA may set the information included in the TB PPDU based on the information included in the trigger frame.

[0242] Reference Fig.16 (c), the user information field may include an AID12 subfield. The AID12 subfield may be used to indicate the intended recipient of the user information field including the AID12 subfield or the function of the user information field. Therefore, the AID12 subfield may also serve to indicate the intended recipient of the trigger frame including the AID12 subfield or the function of the trigger frame. For example, if the value of the AID12 subfield is a preset value, the user information field may indicate a random access resource unit (RA-RU). That is, the preset value of the AID12 subfield may indicate that the user information field indicates the RA-RU. Specifically, if the value of the AID12 subfield is "0", the user information field may indicate the RA-RU for the associated STA. For example, when the value of the AID12 subfield is "0", the user information field may indicate the RA-RU for the associated STA, and when the value of the AID12 subfield is "2045", the user information field may indicate the RA-RU for the unassociated STA. The STA corresponding to the STA ID (e.g., AID (Association ID)) indicated by the value of the AID12 subfield may indicate a response through a user information field including the AID12 subfield or a trigger frame including the AID subfield. For example, the AID12 subfield may represent the AID or the 12 LSBs of the AID. The STA corresponding to the value indicated by the AID12 subfield may send a TB PPDU in response to the received trigger frame. In this case, the value of the AID12 subfield may be in the range of "1" to "2007" (including 1 and 2007), and when the value of the AID12 subfield is a preset value (e.g., "2046"), the RU corresponding to the preset value of the AID12 subfield may not be allocated to any STA. In addition, when the AID subfield is a preset value (e.g., "4095", etc.), the preset value may indicate the start of padding of the trigger frame.

[0243] The information of the user information field including the AID12 subfield may be information corresponding to the STA indicated by the AID12 subfield. For example, the resource unit (RU) allocation subfield may indicate the size and position of the RU. In this case, the value of the RU allocation subfield of the user information field including the AID12 subfield may be information corresponding to the STA indicated by the AID12 subfield. That is, the RU indicated by the RU allocation subfield of the AID12 subfield may be the RU allocated to the STA indicated by the AID12 subfield.

[0244] In addition, the user information field may indicate a coding method (UL FEC coding type), a modulation method (UL HE-MCS, UL DCM), power (UL target RSSI), etc. used to generate a TB PPDU sent in response to a trigger frame.

[0245] Fig.17 A method for indicating a trigger-based (TB) PPDU format according to an embodiment of the present invention is shown.

[0246] Reference Fig.17 , a STA can selectively send PPDUs of different formats based on the indication of the trigger frame indicating the transmission of the PPDU.

[0247] Specifically, the EHT STA may selectively send a legacy PPDU (e.g., HE TB PPDU) and an EHT TB PPDU, and the NEXT STA may selectively send an HE TB PPDU, an EHT TB PPDU, and / or a NEXT TB PPDU. In this case, one frame or one PPDU may be used to separately schedule STAs to which various standards are applied. In a wireless LAN, since STAs to which multiple standards are applied use common resources together, this method may be advantageous. For example, HE STAs (HE STAs other than EHT STAs) and EHT STAs may respond with HE TB PPDUs through one frame. That is, a non-AP STA may instruct not only the HE STA but also the EHT STA to send an HE TB PPDU by sending a trigger frame.

[0248] In addition, information for selecting the TB PPDU format may be included in a trigger frame as a triggered frame, a TRS, a PPDU including a trigger frame, or a PPDU including a TRS control subfield. That is, the AP STA may include information for selecting the TB PPDU format in a trigger frame and send the trigger frame to at least one non-AP STA, and the non-AP STA may select the format of the PPDU of the response based on the information included in the sent trigger frame. Then, the at least one non-AP STA may send the PPDU to the AP based on the selected format.

[0249] Information about the format of the PPDU as a response to the trigger frame (TB PPDU format) may exist at the MAC layer level. The trigger frame as one of the triggered frames may be classified into HE trigger frames, EHT trigger frames, and NEXT trigger frames, and the response to each trigger frame may be classified into HE TB PPDU, EHT TB PPDU, and NEXT TB PPDU.

[0250] In addition, dividing the trigger frame into the HE trigger frame, the EHT trigger frame, and the NEXT trigger frame may mean dividing the TB PPDU format as a response to the trigger frame into the HE TB PPDU, the EHT TB PPDU, and the NEXT TB PPDU.

[0251] The format of the trigger frame used to distinguish the format of the TB PPDU can be identified based on the frame control field included in the MAC header as a HE trigger frame, an EHT trigger frame, or a NEXT trigger frame. Specifically, the format of the trigger frame can be distinguished based on the type subfield, the subtype subfield, and / or the control frame extension subfield. In addition, when the value of the type subfield, the subtype subfield, and / or the control frame extension subfield is a preset value, the trigger frame can be identified as an HE trigger frame, and when the value of the type subfield, the subtype subfield, and / or the control frame extension subfield is another preset value, the trigger frame can be identified as an EHT trigger frame. In addition, when the value of the type subfield, the subtype subfield, and / or the control frame extension subfield is another preset value, the trigger frame can be identified as a NEXT trigger frame.

[0252] For example, when the type subfield is 01 (B3 B2) and the subtype subfield is 0010 (B7 B6 B5 B4), the format of the frame including the type subfield and the subtype subfield may be an HE trigger frame. In this case, an entry using a type subfield, a subtype subfield, and / or a control frame extension subfield having a limited number of bits may be additionally used in the EHT standard and the NEXT standard.

[0253] Alternatively, it is possible to identify whether the format of the trigger frame is a HE trigger frame or an EHT trigger frame based on the common information field included in the trigger frame. That is, the format of the PPDU to be sent as a response to the trigger frame can be determined based on the value of a specific subfield (first subfield) included in the common information field. For example, the non-AP STA can select HE TB PPDU or EHT TB PPDU according to the value of the common information field, and send the selected HE TB PPDU or EHT TB PPDU through the allocated RU. In this case, in addition to the common information field, a specific subfield (second subfield) of the user information field can also be used to identify the format of the PPDU.

[0254] That is, a variant for determining the format of the PPDU as a response to the trigger frame may be determined based on the common information field of the trigger frame, and the format of the PPDU may be determined according to the determined variant. For example, if the variant for determining the PPDU format is determined by the common information field to be a HE variant, the non-AP STA may respond with a HE TB PPDU. If the variant for determining the PPDU format is determined by the common information field to be an EHT variant, the non-AP STA may respond with an EHT TB PPDU.

[0255] In this case, in addition to the common information field, a variant for determining the format of the PPDU may additionally use the user information field.

[0256] For example, the trigger frame may be divided into an HE trigger frame, an EHT trigger frame, or a NEXT trigger frame based on the trigger type subfield. For example, when the trigger type subfield value is a preset value, the trigger frame may be an HE trigger frame. In addition, when the trigger type subfield value is a preset value, the trigger frame may be an EHT trigger frame. When the trigger type subfield value is a preset value, the trigger frame may be a NEXT trigger frame.

[0257] For example, when the trigger type subfield value is 0 to 7, it may be a HE trigger frame, and when the trigger type subfield value is not 0 to 7, it may be an EHT trigger frame or a NEXT trigger frame. The trigger type subfield indicates various types of trigger frame types, however, in this case, there may be a disadvantage that a limited trigger type subfield space needs to be used.

[0258] According to another embodiment, it is possible to distinguish whether the trigger frame is a HE trigger frame, an EHT trigger frame, or a NEXT trigger frame based on the UL length subfield of the trigger frame. For example, it is possible to determine whether the frame is a HE trigger frame, an EHT trigger frame, or a NEXT trigger frame based on a value obtained by performing a mod (remainder) operation on the UL length subfield value. That is, the value of the UL length subfield can be used to determine whether the format of the PPDU sent as a response to the trigger frame is a HE PPDU or an EHT PPDU.

[0259] More specifically, whether the frame is an HE triggered frame, an EHT triggered frame, or a NEXT triggered frame may be determined based on a value obtained by performing a mod (remainder) 3 operation on the UL length subfield value (the remainder when the UL length subfield is divided by 3). For example, when the result obtained by performing a mod 3 operation on the UL length subfield value is not 0, the trigger frame may be an HE triggered frame. Alternatively, when the result obtained by performing a mod 3 operation on the UL length subfield value is 1, the trigger frame may be an HE triggered frame. Alternatively, when the result obtained by performing a mod 3 operation on the UL length subfield value is 0, the trigger frame may not be an HE triggered frame. Alternatively, when the result obtained by performing a mod 3 operation on the UL length subfield value is 0, the trigger frame may be an EHT triggered frame or a NEXT triggered frame.

[0260] That is, when the value obtained by performing mod3 on the value of the UL length subfield of the trigger frame is not 0, the response to the trigger frame can be sent in HETB PPDU, and when the value obtained by performing mod3 on the value of the UL length subfield is 1, the response to the trigger frame can be sent in HETB PPDU.

[0261] In addition, when a value obtained by performing mod3 on the value of the UL Length subfield of the trigger frame is 0, the format of the PPDU transmitted as a response to the trigger frame may be an EHT TB PPDU.

[0262] In addition, in this method, the HE trigger frame, the EHT trigger frame, and the NEXT trigger frame can be distinguished by using an additional trigger frame distinguishing method together. Fig.16 The division method shown is to divide the HE trigger frame, the EHT trigger frame and the NEXT trigger frame.

[0263] According to an embodiment, the format of the trigger frame may be distinguished as a HE trigger frame, an EHT trigger frame, or a NEXT trigger frame based on the user information field of the trigger frame.

[0264] That is, similar to the above-mentioned common information field, whether the format of the trigger frame is a HE trigger frame or an EHT trigger frame can be identified based on the user information field included in the trigger frame. That is, the format of the PPDU sent as a response to the trigger frame can be determined based on the value of the specific subfield (second subfield) included in the user information field. For example, the non-AP STA can select HE TB PPDU or EHT TB PPDU according to the value of the user information field, and send the selected HE TB PPDU or EHT TB PPDU through the allocated RU. In this case, in addition to the user information field, the specific subfield (first subfield) of the common information field can be additionally used to identify the format of the PPDU.

[0265] That is, a variant for determining the format of the PPDU as a response to the trigger frame may be determined based on the user information field of the trigger frame, and the format of the PPDU may be determined according to the determined variant. For example, when the variant for determining the PPDU format is determined by the user information field to be a HE variant, the non-AP STA may respond with a HE TB PPDU, and when the variant for determining the PPDU format is determined by the user information field to be an EHT variant, the non-AP STA may respond with an EHT TB PPDU.

[0266] In this case, a variant for determining the PPDU format may additionally use a common information field in addition to the user information field.

[0267] For example, HE trigger frames, EHT trigger frames, or NEXT trigger frames may be distinguished based on the AID12 subfield. According to an embodiment, HE trigger frames, EHT trigger frames, or NEXT trigger frames may be distinguished based on whether the AID12 subfield includes a preset value. In addition, in this case, there is a problem as to whether the STA indicated by a certain user information field needs to continuously check the AID12 subfield present after the above-mentioned certain user information field to determine the trigger frame format. In order to solve this problem, a user information field including an AID12 subfield indicating which type of trigger frame it is may be present in front of the user information list. In addition, in order to prevent erroneous operation of HE STAs that cannot understand this signaling method, a user information field including an AID12 subfield indicating which type of trigger frame it is may exist after the user information field corresponding to the HE STA.

[0268] In addition, since information of other subfields except the AID12 subfield included in the user information field may not be necessary for the TB PPDU response, the subfield of the user information field including the AID12 subfield indicating which trigger frame is may be omitted. That is, the length of the user information field may be different according to the AID12 subfield. Fig.15 , the AID12 subfield may play a role in indicating the TB PPDU format of the response. For example, when the AID12 subfield has a preset value, the response of the trigger frame including the AID12 subfield set to the preset value may be an EHT TB PPDU. For example, when the AID12 subfield value is 2047, the response of the trigger frame including the AID12 subfield may be an EHT TB PPDU. In addition, when the AID12 subfield has a preset value, the response of the trigger frame including the AID12 subfield set to the preset value may be a NEXT TB PPDU. For example, when the AID12 subfield value is 2048, the response of the trigger frame including the AID12 subfield may be a NEXT TB PPDU.

[0269] According to another embodiment, when responding based on a user information field present at a predetermined position relative to an AID12 subfield having a preset value, a response may be made in a TB PPDU format corresponding to the preset value. For example, when responding based on a user information field present after an AID12 subfield having a preset value, a response may be made in a TB PPDU format corresponding to the preset value. If there are multiple values ​​indicating a TB PPDU format, when responding based on a user information field present after both a preset value 1 and a preset value 2, a response may be made in a TB PPDU format corresponding to the preset value 1 and a TB PPDU format corresponding to the preset value 2 according to a preset priority order. Reference Fig.15 , when responding based on the user information field existing after the AID12 subfield set to 2047, the EHT TB PPDU may be used to respond. In addition, when responding based on the user information field existing after the AID12 subfield set to 2048, the NEXT TB PPDU may be used to respond. In addition, when responding based on the user information field existing after both the AID12 subfield set to 2047 and the AID12 subfield set to 2048, the NEXT TB PPDU may be used to respond. In addition, when responding based on the user information field existing before both the AID12 subfield set to 2047 and the AID12 subfield set to 2048, the HE TB PPDU may be used to respond.

[0270] In this embodiment, the AID12 subfield is used as an example to indicate the type of the trigger frame, but the present invention is not limited thereto, and the type of the trigger frame may be indicated by another subfield of the user information field.

[0271] According to an embodiment, a HE trigger frame, an EHT trigger frame, or a NEXT trigger frame may be distinguished based on a padding field of a trigger frame. For example, whether it is an HE trigger frame, an EHT trigger frame, or a NEXT trigger frame may be determined based on whether the padding field includes a preset value indicating an HE trigger frame, an EHT trigger frame, or a NEXT trigger frame.

[0272] According to an embodiment of the present invention, HE trigger frames, EHT trigger frames, and NEXT trigger frames can be distinguished by combining multiple trigger frame distinction methods described in the present invention. In addition, the description of the trigger frame in the present invention is not limited thereto, but can also be applied to TRS.

[0273] According to another embodiment of the present invention, the AP may not indicate the transmission of both the EHT PPDU and the HE PPDU through a trigger frame. That is, the EHT AP may not send a trigger frame indicating both the HE TB PPDU and the EHT TB PPDU at the same time, but may indicate only one PPDU format.

[0274] Fig.18 A UL MU operation according to another embodiment of the present invention is shown.

[0275] As described above, the transmission of the TB PPDU may be indicated not only by a trigger frame but also by a TRS. In addition, as described above, the TRS may be included in the HT control field. For example, when the HT control field includes an A-control field, the TRS may be included. The TRS may be transmitted through the TRS control subfield. The A-control field may have a form in which the control list field may be continuously connected. In addition, the control list field may include the TRS.

[0276] In addition, the intended receiver of the frame including the TRS may respond to the TRS. For example, the STA corresponding to the RA included in the frame including the TRS may respond to the TRS. The TRS may include information about the length of the PPDU or frame in response to the TRS (UL Data Symbols), the location and size of the RU to be used in response to the TRS (RU Allocation), information about the power in response to the TRS (AP Tx Power, UL Target RSSI), and information about the modulation scheme in response to the TRS (UL HE-MCS), etc.

[0277] Fig.18An embodiment may be used to solve the reference Figure 14 to Figure 15 In addition, as described above, the aforementioned embodiments regarding the trigger frame can also be applied to the TRS. In addition, the above description can be omitted.

[0278] According to an embodiment of the present invention, in addition to the TRS defined in the HE standard (HE TRS), there may also be a TRS defined in the EHT standard or the NEXT standard (EHT TRS, NEXT TRS). Therefore, depending on whether the indicated TRS is HE TRS, EHT TRS, or NEXT TRS, the TB PPDU responding to the TRS may be HE TB PPDU, EHT TB PPDU, or NEXT TB PPDU, respectively. For example, the control ID subfield of the A-control subfield may be used to determine in which standard the TRS is defined. In an additional embodiment, the TRS may be divided into two types, namely, HE TRS and TRS other than HE TRS.

[0279] Alternatively, it may be determined in which standard the TRS is defined according to whether the HT control field is a HE variant, an EHT variant, or a NEXT variant. In addition, the predetermined bit of the HT control field may be determined according to which value the predetermined bit of the HT control field is (HE variant, EHT variant, or NEXT variant). For example, when B0 and B1 of the HT control field are 1 and 1, respectively, it may be an HE variant. In addition, it may be determined whether it is an HE variant, an EHT variant, or a NEXT variant by using B0 and B1 of the HT control field and an additional bit (e.g., B31).

[0280] According to an embodiment of the present invention, the TB PPDU format in response to the TRS may be determined based on the PPDU format including the TRS. That is, when the PPDU indicating the transmission of the PPDU includes the TRS control subfield, the format of the PPDU may be determined based on the format of the PPDU including the TRS control subfield. For example, if the format of the PPDU including the TRS control subfield is HE PPDU, the format of the indicated PPDU may be HE PPDU. However, if the format of the PPDU including the TRS control subfield is EHT PPDU, the format of the indicated PPDU may be EHT PPDU.

[0281] Reference Fig.18When TRS is transmitted through HE PPDU, the TB PPDU in response to TRS may be HE TB PPDU. In addition, when TRS is transmitted through EHT PPDU, the TB PPDU in response to TRS may be EHT TB PPDU. In addition, when TRS is transmitted through NEXT PPDU, the TB PPDU in response to TRS may be NEXT TB PPDU.

[0282] According to an embodiment of the present invention, the subfield included in the TRS may be interpreted differently based on the PPDU format including the TRS. For example, if the TRS is included in the HE PPDU, the UL HE-MCS subfield (or the subfield related to the MCS) included in the TRS may indicate a value corresponding to the HE MCS table. If the TRS is included in the EHT PPDU, the UL HE-MCS subfield (or the subfield related to the MCS) included in the TRS may indicate a value corresponding to the EHT MCS table. If the TRS is included in the NEXT PPDU, the UL HE-MCS subfield (or the subfield related to the MCS) included in the TRS may indicate a value corresponding to the NEXT MCS table. In addition, the interpretation of the RU allocation subfield may also be different based on the PPDU format including the TRS.

[0283] Fig.19 A power management operation performed by a station according to an embodiment of the present invention is shown.

[0284] According to an embodiment of the present invention, a station can operate in a power saving mode (PS). At this time, the station operating in the power saving mode can switch back and forth between an awake state and a doze state. In the awake state, the station operates at full power. In addition, in the awake state, the station can perform transmission and reception. In the doze state, the station can be restricted from sending and receiving. If there are frames to be sent in the cache of the station in the power saving mode, the station can switch to the awake state, and in other cases can operate in the doze state. In the power saving mode, the station may frequently switch between the awake state and the doze state. In the active mode, the station always maintains a state capable of sending and receiving. That is, in the active mode, the station can always operate in the awake state.

[0285] When a station operates in a power saving mode like this, a station in a dormant state may not be able to perform reception. Therefore, the AP may signal the station that traffic to be sent has been buffered, and the station receives a response thereto and performs transmission. For ease of explanation, the AP signaling the station that traffic to be sent is buffered thereon is referred to as traffic indication. In addition, the signaling for traffic indication is referred to as traffic indication signaling. Traffic indication between the AP and the station may be performed as follows. In this specification, traffic may include any one of a frame, a BU, an MSDU, and an MPDU.

[0286] If traffic to be sent to a station is cached on the AP, the AP may send traffic indication signaling indicating that traffic to be sent to the station is cached. In the present specification, according to the context, traffic indication signaling may indicate that traffic is cached, and is not limited to traffic for a specific station. Traffic indication signaling may include at least one of a traffic indication map (TIM: traffic indication map) element and a multilink traffic element. Traffic indication signaling may be in a bitmap format. Specifically, traffic indication signaling may indicate whether traffic corresponding to each bit of the bitmap is cached on the AP that sends the bitmap. In addition, traffic indication signaling may indicate the recipient of the cached traffic. For example, traffic indication signaling may indicate which of group addressed traffic, multicast traffic, broadcast traffic, and individually addressed traffic the cached traffic corresponds to. The bitmap may signal which group the traffic corresponds to and which station the traffic corresponds to based on the position of the bit in the bitmap. Based on the position of the bit in the bitmap, the station may determine whether traffic corresponding to the group including the station is cached on the AP, or whether traffic for the station is cached on the AP.

[0287] The flow indication signaling can be sent based on a predetermined time point. Accordingly, a station in a dormant state can switch from a dormant state to an awake state according to the sending time point of the flow indication signaling. The flow indication signaling can be included in a beacon frame. In addition, the flow indication signaling can be included in a TIM frame. In addition, the AP can periodically send flow indication signaling. Specifically, the AP can send flow indication signaling based on the target beacon transmission time (TBTT). However, if the channel is not idle (busy) within the TBTT, the AP can send the flow indication signaling at a time point later than the TBTT. The station can receive the flow indication signaling by staying awake in the TBTT. The beacon frame including the flow indication signaling may not be accurately sent within the TBTT. Therefore, the station can remain awake for a certain period of time including the TBTT time point.

[0288] In the previously described embodiment, a case where the flow indication signaling is sent by the AP and received by the station is described. At this time, the station may be a non-AP station. In addition, the AP may be included in an AP multi-link device, and the non-AP station may be included in a non-AP multi-link device. In addition, the above-mentioned flow may refer to a bufferable unit (BU) or a buffered BU.

[0289] The AP may send a delivery TIM (DTIM) before sending group-addressed traffic or broadcast traffic. DTIM is a type of TIM that indicates whether group-addressed traffic and broadcast traffic have been cached in the AP. A beacon frame including a DTIM may be referred to as a DTIM beacon frame. If a DTIM received by a station indicates that group traffic for a group including the station is being sent, the station may send signaling to the AP indicating that the group traffic will be received.

[0290] The station receiving the traffic indication signaling may send a signaling for retrieving the transmission for the station. At this time, the signaling for retrieving the transmission for the station may be at least one of a PS-Poll frame or a U-APSD trigger frame. The AP receiving the signaling for retrieving the transmission for the station sends the buffered traffic to the station.

[0291] exist Fig.19 In the embodiment, the first AP AP1 includes a TIM in a beacon frame and sends a beacon frame at each TBTT. The TIM sent by the first AP AP1 indicates that there is traffic for the first station STA1 in the cache. The first station STA1 sends a PS-poll frame and remains awake to receive traffic. The first AP AP1 sends the cached traffic (data sent to STA1) to the first station STA1. The first station STA1 can receive the cached traffic and enter a sleep state. In addition, the first station STA1 can remain awake when sending the next TIM.

[0292] In addition, Fig.19 , the first AP AP1 sends DTIM in every three beacon frames. Therefore, the DTIM interval is 3 beacon frames. At this time, the first station STA1 operating in the power saving mode remains awake whenever a TIM is sent. The first AP AP1 sends broadcast traffic or group-addressed traffic after sending the DTIM beacon. When the DTIM indicates that the broadcast traffic or group-addressed traffic to be received by the first station STA1 is cached, the first station STA1 remains awake to receive the broadcast traffic or group-addressed traffic. As a result, even in the power saving mode, the first station STA1 can stably receive the broadcast traffic or group-addressed traffic. Refer to Fig. 20 , the format of the TIM element that may be included in the traffic indication signaling will be described.

[0293] Fig. 20 The format of a TIM element according to an embodiment of the present invention is shown.

[0294] The TIM element includes the TIM as described above. The TIM element may include at least any one of an element ID subfield, a length subfield, a DTIM count subfield, a DTIM period subfield, a bitmap control subfield, and a partial virtual bitmap subfield. The length of the element ID subfield, the length subfield, the DTIM count subfield, the DTIM period subfield, and the bitmap control subfield is 1 octet, i.e., 8 bits. The partial virtual bitmap subfield may have a variable length within a maximum of 251 octets. The length of the partial virtual bitmap subfield may be determined by the bitmap control field or the bitmap offset subfield of the bitmap control field.

[0295] The element ID subfield indicates the ID of the element including the element ID subfield.

[0296] The length subfield indicates the length of the element including the length subfield. Specifically, the length subfield may indicate the length of the element excluding the element ID subfield and the length subfield.

[0297] The DTIM count subfield indicates how many beacon frames will be sent until the next DTIM. Specifically, the value of the DTIM count subfield may indicate how many beacon frames will be sent until the next DTIM, including the beacon frame containing the DTIM count subfield. For example, if the value of the DTIM count subfield is 0, it may indicate that the DTIM count subfield is included in the DTIM beacon.

[0298] The DTIM Period subfield indicates the number of beacon frames sent between DTIMs. If all TIMs are DTIMs, the value of the DTIM Period subfield is set to 1.

[0299] The bitmap control subfield may include a traffic indicator subfield and a bitmap offset subfield. The traffic indicator subfield may be a 1-bit field, and the bitmap offset subfield may be a 7-bit field. The traffic indicator subfield may indicate whether the group-addressed traffic is cached. Specifically, if the group-addressed traffic is cached, the AP may set the value of the traffic indicator subfield to 1. The group-addressed traffic may be traffic whose AID of the receiver is 0. The bitmap offset subfield indicates the starting point of the bit corresponding to the partial virtual bitmap in the traffic indication virtual bitmap. The AID (association ID) corresponding to the partial virtual bitmap is determined according to the bitmap offset subfield.

[0300] Each bit in the partial virtual bitmap field indicates whether the traffic to be sent to the station of the AID corresponding to each bit is cached in the AP that sends the TIM. If the value of the bit in the partial virtual bitmap field is 1, it can indicate that the traffic to be sent to the station of the AID corresponding to the bit in the partial virtual bitmap field has been cached in the AP that sends the TIM. If the value of the bit in the partial virtual bitmap field is 0, it can indicate that the traffic to be sent to the station of the AID corresponding to the bit in the partial virtual bitmap field has not been cached in the AP that sends the TIM. Therefore, if the value of the bit in the partial virtual bitmap field is 1, the station that receives the TIM can determine that the traffic to be sent to the station of the AID corresponding to the bit in the partial virtual bitmap field has been cached in the AP that sends the TIM. If the value of the bit in the partial virtual bitmap field is 0, the station that receives the TIM can determine that the traffic to be sent to the station of the AID corresponding to the bit in the partial virtual bitmap field is not cached in the AP that sends the TIM. In addition, the station receiving the TIM may determine that traffic to be sent to stations of AIDs not indicated by the partial virtual bitmap is not cached in the AP that sends the TIM.

[0301] The TIM element may include a traffic indication virtual bitmap subfield. At this time, the bit number in the traffic indication virtual bitmap subfield may indicate the AID of the station corresponding to the bit. Specifically, the bit numbered n in the traffic indication virtual bitmap subfield indicates whether the frame to be sent to the station with AID n is cached in the AP that sends the TIM element. Specifically, if the bit number in the traffic indication virtual bitmap subfield is N, the bit may indicate whether the traffic to be sent to the station with AID N or the group with group ID N is cached in the AP that sends the TIM. The TIM may include a partial virtual bitmap subfield instead of a traffic indication virtual bitmap subfield. The partial virtual bitmap subfield is formed by omitting continuous bits with a value of 0 from the traffic indication virtual bitmap subfield. The partial virtual bitmap subfield may omit the first continuous bit in the set of continuous bits with a value of 0 in the traffic indication virtual bitmap subfield or omit the last continuous bit. Specifically, the partial virtual bitmap subfield may be the bits of the octet numbers N1 to N2 of the traffic indication virtual bitmap subfield. N1 can be the largest even number in the traffic indication virtual bitmap subfield with bit numbers 1 to (N1*8-1) all being 0. N2 can be the smallest number in the traffic indication virtual bitmap subfield with bit numbers (N2+1)*8 to 2007 all being 0. This can be a method of configuring a partial virtual bitmap subfield when multiple BSSID sets are not supported, i.e., when dot11MultiBSSIDImplemented is "false". In this specification, the bit number n of a bitmap or subfield refers to the n+1th bit among the bits of the bitmap or subfield.

[0302] If the values ​​of all bits except the bit number 0 in the traffic indication virtual bitmap subfield are 0, the length of the partial virtual bitmap subfield is 1 octet, and the values ​​of all bits in the partial virtual bitmap subfield may be set to 0. At this time, the value of the bitmap offset field may be 0, and the value of the length field may be set to 4.

[0303] In addition, when the value of all bits of the traffic indication virtual bitmap subfield is 0 and the value of all bits of the bitmap control subfield is 0, the TIM element may not include the partial virtual bitmap field and the bitmap control field. At this time, the value of the length field may be set to 2. In this way, when the TIM has a partial virtual bitmap field, it may have a bitmap control field.

[0304] When multiple BSSID sets are supported, that is, when dot11MultiBSSIDImplemented is true ("True"), the method for configuring the partial virtual bitmap subfield can be performed according to the following embodiment. When using multiple BSSID sets, the management frame sent by the AP corresponding to the transmitted BSSID may include information for the BSS corresponding to the non-transmitted BSSID. At this time, the management frame may include at least any one of a beacon frame and a probe response frame. The TIM element of the beacon frame sent from the transmitted BSSID may indicate whether the AP corresponding to the non-transmitted BSSID included in the multi-BSSID set including the transmitted BSSID caches the frame. A method for configuring the partial virtual bitmap subfield taking this into account will be described.

[0305] When the maximum number of BSSIDs that a multi-BSSID set can have is n, the bits of bitmap number 1 to bitmap number (2^n-1) of the traffic indication virtual bitmap subfield can indicate whether the group-addressed frame is cached in the AP that sends the TIM element. At this time, the group-addressed frame can be a frame cached in the AP corresponding to the non-transmission BSSID. Therefore, the group-addressed frame is a group-addressed frame of the AP or BSS corresponding to the non-transmission BSSID. Each of the bits of bitmap number 1 to bitmap number (2^n-1) in the traffic indication virtual bitmap subfield can indicate whether a frame is cached in the AP corresponding to each bit. At this time, the bits with bit numbers greater than (2^n-1) in the traffic indication virtual bitmap subfield indicate whether the frame to be sent to the station with AID n is cached in the AP that sends the TIM element. Therefore, the AP may not allocate 1 to (2^n-1) as AIDs. In this embodiment, the bit corresponding to the inactive non-transmission BSSID can be set to a reserved bit. At this time, the value of the reserved bit can be set to 0. In addition, the AP can allocate a number equal to or greater than 2^n as the AID of the station. At this time, the AP can allocate the AID of the station from a value between 2^n and 2007. The EHT AP may not allocate 2007 as the AID. In this way, the range that can be allocated as an AID is called an AID space. The transmission BSSID and the non-transmission BSSID can share an AID space. In a specific embodiment, the EHT AP may not allocate 2007 as the AID of the station.

[0306] The maximum number n of BSSIDs that a multi-BSSID set can have may be signaled through the multi-BSSID element. n may be the value indicated by the MaxBSSID indicator of the multi-BSSID element.

[0307] A method for configuring sub-fields of a partial virtual bitmap will be described. The method for configuring sub-fields of a partial virtual bitmap may vary according to the functions related to the multi-BSSID set of the AP that sends the TIM element. A non-S1G AP can configure sub-fields of the partial virtual bitmap by method A or method B. Additionally, an S1G AP can configure sub-fields of the partial virtual bitmap by method C. A non-HT AP, HT AP, VHT AP, HE AP, and EHT AP can all be non-S1G APs. An S1G AP refers to an AP that operates in a frequency band below 1 GHz, and a non-S1G AP refers to an AP that operates in a frequency band greater than 1 GHz.

[0308] First, method A will be explained. The sub-fields of the partial virtual bitmap can consist of the bits of byte numbers 0 to N2 of the traffic indication virtual bitmap. N2 is the smallest number that satisfies the condition that all bit values from bit number (N2 + 1)*8 to 2007 in the traffic indication virtual bitmap are 0. If there is no N2 that satisfies this condition, then N2 is 250. In method A, the value of the bitmap offset field is 0. Additionally, the value of the length field is N2 + 4.

[0309] Method B will be explained. The sub-fields of the partial virtual bitmap can consist of the bits of byte numbers 0 to (N0 - 1) of the traffic indication virtual bitmap and the bits of byte numbers N1 to N2 of the traffic indication virtual bitmap. N0 can be the largest positive integer that satisfies (N0*8 - 2^n < 8). When N0 is odd, N1 can be the largest even number that satisfies N0 < N1 and all bit values from bit number N0*8 to (N1*8 - 1) are 0. If there is no value N1 > N0, then N1 can be N0. Additionally, N2 is the smallest positive integer that satisfies the condition that all bit values from bit number (N2 + 1)*8 to 2007 in the traffic indication virtual bitmap are 0. If there is no N2 that satisfies this condition, N2 can be 250. In method B, the value of the bitmap offset field is (N1 - N0) / 2. Additionally, the value of the length field is (N0 + N2 - N1 + 4). If there are no buffered frames in any BSS corresponding to the transmitting BSSID and non-transmitting BSSID, the length of the partial virtual bitmap sub-field is 1 byte, and all bit values of the partial virtual bitmap sub-field can be set to 0. At this time, the value of the bitmap offset field is 0. Additionally, the value of the length field is 4.

[0310] If the individually addressed frame is not cached in any of the BSSs corresponding to the transmitting BSSID and the non-transmitting BSSID, and the group addressed frame is cached in one or more BSSs, the subfield of the partial virtual bitmap consists of the bits of octet numbers 0 to (N0-1). N0 is the largest positive integer that satisfies (N0*8-2^n)<8.

[0311] It may be necessary to indicate the amount of traffic buffered on each of the multiple links operated by a multilink device. This will be done by Figures 13 to 18 To explain.

[0312] Fig.21 The format of a multi-link traffic element according to an embodiment of the present invention is shown.

[0313] APs operating on a multi-link device can share an AID space. Specifically, a multi-link device can have one AID space. In this case, when Fig. 20 When the TIM element described indicates a cached frame to the AP, it may be difficult for the station to determine on which link the frame is cached. A flow indication signaling method is needed to solve this problem. Specifically, the multi-link device can perform flow indication signaling for each link. In a specific embodiment, the multi-link device can perform flow indication signaling for each station attached to the multi-link device. The TIM element sent by the multi-link device can indicate whether there is a cached frame in each of the multiple links operated by the multi-link device. At this time, the TIM element sent by the multi-link device is called a multi-link flow element.

[0314] The multilink device may transmit the multilink traffic element through a beacon frame or a TIM frame. In addition, the multilink traffic element may be included in a frame including a TIM element.

[0315] exist Fig.21 In the multi-link traffic element, the multi-link traffic element may include an element ID subfield, a length subfield, an element ID extension subfield, a multi-link traffic control subfield, and a per-link traffic indication list (Per-Link Traffic Indication List) subfield.

[0316] The element ID subfield is a 1-octet field and indicates the ID of the element including the element ID subfield.

[0317] The length subfield is a 1-octet field and indicates the length of the element including the length subfield. Specifically, the length subfield may indicate the length of the element excluding the element ID subfield and the length subfield.

[0318] The Element ID Extension subfield is a 1-octet field and is combined with the value of the Element ID subfield including the Element ID Extension subfield to indicate a value that identifies an element.

[0319] The Multi-Link Traffic Control subfield is a 1-octet field and includes a Bitmap Size subfield and an AID Offset subfield. The Bitmap Size subfield is a 4-bit subfield and indicates the size of the Per-Link Traffic Indication Bitmap subfield. If the value of the Bitmap Size is M, the size of the Per-Link Traffic Indication Bitmap subfield may be M+1. The value 0 for the Bitmap Size is a reserved value.

[0320] The AID offset subfield is an 11-bit subfield and indicates the starting position of the bit of the flow indication virtual bitmap indicated by each link flow indication list or each link flow indication bitmap subfield. Therefore, for the AID offset subfield, the AID (association ID) corresponding to each link flow indication list or each link flow indication bitmap subfield is determined according to the AID offset subfield. If the value of the AID offset is K, each link flow indication list or each link flow indication bitmap subfield starts indicating from the bit number K of the flow indication virtual bitmap. In addition, if the value of the AID offset subfield is K, the minimum value in the AID corresponding to each link flow indication list or each link flow indication bitmap subfield is K. Each link flow indication list subfield is a variable length field and may include one or more link flow indication bitmap subfields. If the value of the AID offset subfield is K, each link flow indication bitmap subfield starts indicating from the bit number K of the flow indication virtual bitmap. The number of each link traffic indication bitmap subfield included in each link traffic indication list subfield may be the number of bits set to 1 among the bits corresponding to the AID of the non-AP multi-link device in the partial virtual bitmap. The plurality of each link traffic indication bitmap subfields may be sorted according to the AID corresponding to each link traffic indication bitmap subfield in each link traffic indication list subfield. Specifically, the plurality of each link traffic indication bitmap subfields may be arranged in ascending order of the AID corresponding to each link traffic indication bitmap subfield in each link traffic indication list subfield.

[0321] If the value of the bitmap size field is m, the size of each link traffic indication bitmap subfield is m+1 bits. If the TID-to-link mapping negotiation is successfully performed, the bit in each link traffic indication bitmap subfield indicates whether to cache traffic to be sent to the non-AP station operating on the link corresponding to the bit. Specifically, when the value of the bit in each link traffic indication bitmap subfield is 1, the bit in each link traffic indication bitmap subfield may indicate that traffic to be sent to the non-AP station operating on the link corresponding to the link is cached. If the value of the bit in each link traffic indication bitmap subfield is 0, the bit in each link traffic indication bitmap subfield may indicate that traffic to be sent to the non-AP station operating on the link corresponding to the bit is not cached. If the TID-to-link mapping is the default mapping, the bit in each link traffic indication bitmap subfield may indicate whether to request (acquire) the transmission of the cached traffic on the link corresponding to the bit. Specifically, when the value of the bit in each link traffic indication bitmap subfield is 1, the bit in each link traffic indication bitmap subfield may indicate that it is recommended to request to transmit the cached traffic on the link corresponding to the bit. If the TID to link mapping of a certain link corresponds to the default mapping, the uplink transmission and the downlink transmission performed on the link may be performed without TID restriction. In addition, the default mapping is applicable to the link for which the TID to link mapping negotiation is not successfully performed. Therefore, the case where the TID to link mapping negotiation is successfully performed may indicate the case where the TID to link mapping negotiation is successfully performed and not all TIDs are mapped to all links.

[0322] The bits in each link traffic indication bitmap subfield are mapped to the link according to the bit number of the bit. Specifically, in each link traffic indication bitmap subfield, the bit corresponding to the bit number n can be mapped to the link with the link ID n. In addition, each link traffic indication list subfield can include a padding field. Thus, each link traffic indication list subfield can have a length in octets. The padding field can have a length between 0 bits and 7 bits.

[0323] The AP multilink device may send a frame including both a multilink traffic element and a TIM element. In this case, the frame may be a beacon frame. Fig.14 A method in which an AP multi-link device uses a multi-link traffic element and a TIM element to signal traffic buffered in the AP multi-link device is described.

[0324] Fig. 22 A method for signaling traffic buffered in an AP multi-link device by using a multi-link traffic element and a partial virtual bitmap subfield of a TIM element according to an embodiment of the present invention is shown.

[0325] The bits corresponding to the non-AP multi-link device in the partial virtual bitmap subfields or traffic indication virtual bitmap of the TIM element sent by the AP multi-link device may be set to 1. At this time, the non-AP multi-link device may parse the multi-link traffic element. The non-AP multi-link device determines which link the request (acquisition) for transmission of the cached traffic is recommended or which link has the traffic cached based on the link traffic indication bitmap subfields corresponding to the non-AP multi-link device in the multi-link traffic element. Fig.21 As shown, when the TID-to-link mapping negotiation is successfully performed, the non-AP multi-link device can determine whether to cache traffic to be sent to a station of the non-AP multi-link device operating on the link corresponding to the bit based on the value of the bit in the traffic indication bitmap subfield of each link corresponding to the non-AP multi-link device. In addition, when the TID-to-link mapping is the default mapping, the non-AP multi-link device can indicate whether to recommend requesting the transmission of the cached traffic on the link corresponding to the bit based on the value of the bit in the traffic indication bitmap subfield of each link corresponding to the non-AP multi-link device.

[0326] The non-AP multi-link device may request the AP multi-link device to transmit the cached traffic on the link corresponding to the bit set to 1 in the bit of the traffic indication bitmap subfield of each link corresponding to the non-AP multi-link device. Specifically, if the TID-to-link mapping negotiation is successfully performed, the non-AP multi-link device may request the AP multi-link device to transmit the cached traffic on the link corresponding to the bit set to 1 in the bit of the traffic indication bitmap subfield of each link corresponding to the non-AP multi-link device. If the TID-to-link mapping is a default mapping, the non-AP multi-link device may request the AP multi-link device to transmit the cached traffic on one or more links including the link corresponding to the bit set to 1 in the bit of the traffic indication bitmap subfield of each link corresponding to the non-AP multi-link device. In these embodiments, the non-AP multi-link device may request the AP multi-link device to transmit the cached traffic by sending a U-APSD trigger frame or sending a PS-poll frame. When receiving the request for transmission of the cached traffic, the AP multi-link device may send the cached traffic to the non-AP multi-link device. Additionally, when receiving a request for transmission of buffered traffic, the AP multi-link device may send a QoS Null frame instead of the buffered traffic.

[0327] exist Fig. 22 In the embodiment of the present invention, a legacy station before EHT or a station whose TID-to-link mapping is set as a default mapping is assigned a value less than K as the AID value. A non-AP station that has successfully performed negotiation on the TID-to-link mapping is assigned a value equal to or greater than K as the AID value. Fig. 22In the traffic indication virtual bitmap, all bits less than bit number (N-1)*8 are set to 0. Therefore, the AP multilink device does not cache traffic for stations with AIDs less than (N-1)*8. Among the bits corresponding to the bits with bit number (N-1)*8 or more, at least one bit is set to 1. N-1 is an even number, and the value of N*8 is k. Therefore, starting from bit number (N-1)*8 of the traffic indication virtual bitmap, it is included in the partial virtual bitmap subfield. At this time, the value of the bitmap offset subfield of the partial virtual bitmap subfield is set to (N-1) / 2. In addition, among the bits of the partial virtual bitmap subfield, the values ​​of the bits corresponding to AIDs (N-1)*8, (N-1)*8+2, (N-1)*8+3, k, k+2, and k+3 are set to 1.

[0328] As described above, the AID offset subfield of the multilink traffic element may indicate the AID of the multilink device corresponding to the frontmost of each link traffic indication bitmap subfield of the multilink traffic element. Fig. 22 In the AID offset subfield, the value of the AID offset subfield is set to K. The multilink traffic element includes each link traffic indication bitmap subfield corresponding to the multilink device indicated as 1 in the partial virtual bitmap subfield. Fig. 22 In the multi-link traffic element, each link traffic indication bitmap subfield is used for each of the stations or non-AP multi-link devices whose AIDs correspond to k, k+2, and k+3. At this time, each link traffic indication bitmap subfield is sorted in ascending order of AID.

[0329] The value of the bitmap size field of the multi-link traffic element is 2. Therefore, each link traffic indication bitmap subfield of the multi-link traffic element includes 3 bits. At this time, the first bit (B0) of each link traffic indication bitmap subfield is mapped to the link with link ID 0, the second bit (B1) is mapped to the link with link ID 1, and the third bit (B2) is mapped to the link with link ID 2.

[0330] As described above, the corresponding multi-link device with an AID value of K applies the default mapping, and the multi-link devices corresponding to AID values ​​K+2 and K+3 successfully perform TID-to-link mapping. Therefore, the traffic indication bitmap subfield corresponding to AID K indicates that it is recommended to request the transmission of cached traffic on the link with link ID 1. In addition, the traffic indication bitmap subfield corresponding to AID K+2 indicates that there is traffic cached on two links with link ID 1 and link ID 2 in the AP multi-link device. At this time, the traffic cached on the link with link ID 1 and the traffic cached on the link with link ID 2 may be the same or different. In addition, the traffic indication bitmap subfield corresponding to AID K+3 indicates that there is traffic cached on the link with link ID 1 in the AP multi-link device.

[0331] However, it may not be guaranteed that the AIDs of the non-AP multi-link devices connected to the AP multi-link device are continuously allocated. In addition, the AIDs of the non-AP stations not included in the multi-link device may be allocated to the AIDs among the AIDs of the non-AP multi-link device. At this time, it may be difficult for the non-AP multi-link device to determine which AID is attached to the station not included in the non-AP multi-link device. Therefore, if the multi-link traffic element does not include the link traffic bitmap subfields for the stations not included in the non-AP multi-link device, it may be difficult for the non-AP multi-link device to parse the link traffic bitmap subfields. For example, in Fig. 22 In the embodiment of the present invention, AID K+1 can be assigned to the non-AP multi-link device, and the value of the bit corresponding to AID K+1 in the partial virtual bitmap subfield of the TIM element can be 1. At this time, the non-AP multi-link device with AID K+2 or K+3 may not be able to determine which of the three link traffic bitmap subfields is the link traffic bitmap subfield for the non-AP multi-link device. Therefore, a method for setting a multi-link traffic element is needed to solve this problem. This will be achieved by Fig.23 To explain.

[0332] Fig.23 A method for setting a multi-link traffic element according to an embodiment of the present invention is shown.

[0333] In an embodiment of the present invention, an AP multi-link device may include, in a multi-link traffic element, a respective link traffic bitmap subfield for a non-AP station not included in the multi-link device. Specifically, if the value of the bit of the traffic indication bitmap subfield or the partial virtual bitmap subfield corresponding to the non-AP station is 1, even if the non-AP station is a non-AP station not included in the multi-link device, the AP multi-link device may include, in the multi-link traffic element, the respective link traffic bitmap subfield for the non-AP station. Therefore, the AP multi-link device may include, in the multi-link traffic element, the respective link traffic bitmap subfield for all stations corresponding to the bit set to 1 among the bit of the traffic indication bitmap subfield or the bit of the partial virtual bitmap subfield. For ease of explanation, a station corresponding to the bit set to 1 among the bit of the traffic indication bitmap subfield or the bit of the partial virtual bitmap subfield is referred to as a station instructed to cache traffic.

[0334] At this time, the AP multi-link device may include, in the multi-link traffic element, the link traffic bitmap subfields for all stations instructed to cache traffic, regardless of whether the stations instructed to cache traffic are stations attached to the multi-link device, whether they correspond to non-AP multi-link devices, or to which AP or BSS they are attached. Which AP or BSS the stations instructed to cache traffic are attached to may indicate whether the stations instructed to cache traffic are attached to multiple BSSID sets.

[0335] The AP multilink device may include the same number of link traffic bitmap subfields as the number of stations instructed to buffer traffic in the multilink traffic element. A method for the AP multilink device to set the link traffic bitmap subfields corresponding to stations not attached to the multilink device will be described.

[0336] The AP multi-link device may set the value of all bits in each link traffic bitmap subfield corresponding to the station not attached to the multi-link device to 0. That is, the AP multi-link device may set the value of the bit in each link traffic bitmap subfield corresponding to the station not attached to the multi-link device to a reserved field. In another specific embodiment, the AP multi-link device may set the value of the bit in each link traffic bitmap subfield corresponding to the station not attached to the multi-link device to an arbitrary value. In another specific embodiment, the AP multi-link device may set the value of the bit in each link traffic bitmap subfield corresponding to the station not attached to the multi-link device to 1. At this time, the non-AP multi-link device may ignore the value of the bit in each link traffic bitmap subfield corresponding to the station not attached to the multi-link device. In another specific embodiment, the AP multi-link device may set the value of the bit in each link traffic bitmap subfield corresponding to the station not attached to the multi-link device to 1. In another specific embodiment, the AP multi-link device may set the value of the bit corresponding to the link operated by the station not attached to the multi-link device among the bits of each link traffic bitmap subfield to 1, and set the value of the remaining bits to 0.

[0337] exist Fig.23 In the embodiment of the present invention, the setting of the flow indication virtual bitmap and the setting of the partial virtual bitmap subfield can be Fig. 22 The traffic indication virtual bitmap setting is the same as the partial virtual bitmap subfield setting. Fig.23 In the embodiment of the present invention, AID k and AID k+3 correspond to non-AP multilink devices. AID k+2 corresponds to a station not included in the multilink device. The link traffic bitmap subfields of the multilink traffic element corresponding to AID k and AID k+3 are as follows: Fig. 22 Since AID K+2 is a station not included in the multi-link device, all bits in the link traffic bitmap subfield corresponding to AID k+2 of the multi-link traffic element are set to 0.

[0338] The AID offset subfield of the multi-link traffic element may indicate the bits of the traffic indication virtual bitmap and the bits of the partial virtual bitmap subfield that are after all the bits corresponding to the group ID and the group addressed frame. At this time, the group ID may include an AID value of 0. In addition, the group ID may include the bit number of the traffic indication virtual bitmap corresponding to the multi-BSSID set, that is, the AID corresponding to the bit number. In addition, the group ID may include the bit number of the traffic indication virtual bitmap corresponding to the transmission BSSID and the non-transmission BSSID, that is, the AID corresponding to the bit number. When the maximum number of BSSIDs that can be used as a multi-BSSID set is 2^n, the group ID may include values ​​corresponding to AID 0 to (2^n-1). When a multi-BSSID set is used and the maximum number of BSSIDs that can be used as a multi-BSSID set is 2^n, the AID offset subfield may indicate a value after the value corresponding to AID 0 to (2^n-1). This setting of the AID offset field is because the group addressed frame is not limited to being sent over a specific link, so it may not make much sense to signal each link.

[0339] According to another embodiment of the present invention, even if the AID offset subfield indicates the bits before the bits indicating the group ID in the bits of the flow indication virtual bitmap and the bits of the partial virtual bitmap subfield, the link flow indication bitmap subfields corresponding to the group ID may not be included in the multi-link flow element. Even if the AID offset subfield indicates the bits before the bits indicating the group ID in the bits of the flow indication virtual bitmap and the bits of the partial virtual bitmap subfield, the multi-link flow element may only include the link flow indication bitmap subfields corresponding to the individual stations in the stations indicated to cache the flow. Specifically, when the maximum number of BSSIDs that can be set to a multi-BSSID set is 2^n, the AID offset subfield may indicate the bits corresponding to the AIDs below (2^n-1) in the bits of the flow indication virtual bitmap and the bits of the partial virtual bitmap subfield. At this time, the multi-link flow element may only include the link flow indication bitmaps corresponding to the bits set to 1 in the bits of the flow indication virtual bitmap and the bits corresponding to the AID 2^n in the bits of the partial virtual bitmap subfield. The station receiving the multi-link traffic element may determine that the multi-link traffic element includes only the link traffic indication bitmaps corresponding to the bits of the traffic indication virtual bitmap and the bits of the partial virtual bitmap subfield corresponding to AID 2^n and the bits set to 1.

[0340] According to another embodiment of the present invention, regardless of whether the AID offset subfield indicates the bit before the bit indicating the group ID in the bit of the traffic indication virtual bitmap and the bit of the partial virtual bitmap subfield, the multi-link traffic element may include the link traffic indication bitmaps corresponding to each of all the bits set to 1 among the bits after the bit indicated by the AID offset subfield in the traffic indication virtual bitmap and the partial virtual bitmap subfield. At this time, the AP multi-link device may set all the values ​​of the link traffic indication bitmap fields corresponding to the bits of the traffic indication virtual bitmap and the partial virtual bitmap subfield corresponding to the group address to a predetermined value. The predetermined value may be 0. In another specific embodiment, the AP multi-link device may set the values ​​of the link traffic indication bitmap fields corresponding to the bits of the traffic indication virtual bitmap and the partial virtual bitmap subfield corresponding to the group address to any value. The AP multi-link device may set the bits corresponding to the links in which the group addressed frames are sent among the bits of the link traffic indication bitmap fields corresponding to the bits of the traffic indication virtual bitmap and the partial virtual bitmap subfield corresponding to the group address to 1, and set the remaining bits to 0.

[0341] Fig.24 The method for setting each link traffic bitmap subfield of a multi-link traffic element according to an embodiment of the present invention is shown when the link set operated by an AP multi-link device and the link set operated by a non-AP multi-link device communicating with the AP multi-link device are different.

[0342] The link set operated by the AP multi-link device and the link set operated by the non-AP multi-link device communicating with the AP multi-link device may be different. For example, the AP multi-link device may communicate with the first non-AP multi-link device in the first link to the third link, and the AP multi-link device may communicate with the second non-AP multi-link device in the first link to the second link. In this case, there may be problems with the method for setting the link traffic bitmap subfields of the multi-link traffic element.

[0343] Even if the link set operated by the AP multi-link device is different from the link set operated by the non-AP multi-link device communicating with the AP multi-link device, the AP can set the sizes of all the link traffic indication bitmap subfields included in the multi-link traffic element to be the same, and can set the links to which each bit of all the link traffic indication bitmap subfields is mapped to be the same. Specifically, the AP multi-link device can set the number of bits of all the link traffic indication bitmap subfields included in the multi-link traffic element to be greater than the number of links set by the AP multi-link device. This is because the multiple link IDs set by the AP multi-link device may not start from 0 or the IDs of the multiple links may not be continuous. For example, the AP multi-link device can set the number of bits of all the link traffic indication bitmap subfields included in the multi-link traffic element to the maximum number of links that the AP multi-link device can set. In another specific embodiment, the AP multi-link device can set the number of bits of all the link traffic indication bitmap subfields included in the multi-link traffic element to the number obtained by adding 1 to the value of the maximum link ID that the AP multi-link device can set.

[0344] There may be a problem when setting the bit value of each link flow indication bitmap subfield corresponding to the link not set by the AP multi-link device and the link not set by the non-AP multi-link device corresponding to the link flow indication bitmap subfield. For the convenience of explanation, the bit of each link flow indication bitmap subfield corresponding to the link not set by the AP multi-link device and the link not set by the non-AP multi-link device corresponding to the link flow indication bitmap subfield is called a no-link bit. The AP multi-link device can set the value of the no-link bit to a predetermined value. Therefore, the AP multi-link device can set the bit of each link flow indication bitmap subfield corresponding to the link not set by the AP multi-link device or the non-AP multi-link device to a predetermined value. At this time, the predetermined value can be 0. In another specific embodiment, the AP multi-link device can set the value of the no-link bit to an arbitrary value. At this time, the non-AP station can ignore the value of the no-link bit.

[0345] In addition, the value of the bit corresponding to the disabled link in each link traffic indication bitmap subfield may be set to reserved. Specifically, the value of the bit corresponding to the disabled link in each link traffic indication bitmap subfield may be set to 0. At this time, the disabled link may be a link on which uplink and downlink transmissions have been stopped. Specifically, the disabled link may be a link on which uplink transmission and downlink transmission for individually addressed frames have been stopped. At this time, the non-AP station may ignore the value of the non-disabled bit.

[0346] exist Fig.24 In the embodiment, Fig.24As shown in (a), the AP multi-link device AP MLD operates on the first link Link0 to the third link Link2. The first multi-link device MLD1 and the AP multi-link device AP MLD set the first link Link0 to the third link Link2. The second multi-link device MLD2 and the AP multi-link device AP MLD set the first link Link0 to the second link Link1. The AP multi-link device AP MLD sets the number of bits of each link bitmap subfield of the multi-link traffic element to 3 bits. The multi-link traffic element sent by the AP multi-link device AP MLD includes each link bitmap subfield corresponding to the first multi-link device MLD1, the first station STA1 and the second multi-link device MLD2 respectively. The AP multi-link device AP MLD Fig. 22 and Fig.23 The described embodiment sets the value of each link bitmap subfield corresponding to the first multi-link device MLD1. Fig.23 The described embodiment sets the value of each link bitmap subfield corresponding to the first station STA1. The AP multi-link device AP MLD sets the value of each link bitmap subfield corresponding to the first station STA1 according to the reference Fig. 22 and Fig.23 The described embodiment sets the values ​​of the first bit B0 to the second bit B1 of each link bitmap subfield corresponding to the second multi-link device MLD2. In addition, the AP multi-link device AP MLD sets the value of the third bit B2 of each link bitmap subfield corresponding to the second multi-link device MLD2 to a predetermined value, i.e., 0, as described above.

[0347] In the implementation described above, the bit number of the bit in each link traffic indication bitmap subfield and the ID of the link corresponding to the bit are described as being the same. According to a specific embodiment, the bit number of the bit in each link traffic indication bitmap subfield and the ID of the link corresponding to the bit may be different. The link ID of the link set by the AP multi-link device that sends each link traffic indication bitmap subfield may be mapped to the bit number of the bit in each link traffic indication bitmap subfield in ascending order. The AP multi-link device sets a link with an ID of 1 and a link with an ID of 3, and each link traffic indication bitmap subfield may be a 2-bit field. At this time, the first bit B0 of each link traffic indication bitmap subfield is mapped to the link with an ID of 1, and the second bit B1 is mapped to the link with an ID of 3.

[0348] Will pass Figure 25 to Figure 29 A method for setting up multilink is described. First, reference will be made to Fig.25 Describes a multilink element.

[0349] Fig.25Signaling related to multilink elements and MediumSyncDelay according to an embodiment of the present invention is shown.

[0350] The multilink device may use the multilink element to perform multilink discovery and multilink setting. At this time, the multilink element may be included in the management frame. Specifically, the multilink element may be included in at least any one of a beacon frame, a probe request frame, a probe response frame, an authentication frame, an association request frame, an association response frame, a reassociation request frame, and a reassociation response frame.

[0351] The multilink element may include an element ID subfield, a length subfield, an element ID extension subfield, a multilink control subfield, a public information subfield, and a link information subfield. The element ID subfield or the element ID extension subfield may indicate the ID of the element including the element ID subfield or the element ID extension subfield. The length subfield may indicate the length of the element including the length subfield. The multilink control subfield may include a type subfield and an existence bitmap subfield. The type subfield may indicate what type the multilink element is. In addition, the format of the multilink element may be determined based on the type of the multilink element. The existence bitmap subfield may indicate whether a subfield that may be included in the multilink element is included. For example, the existence bitmap subfield may indicate whether a subfield that may be included in the public information subfield included in the multilink element is included. The subfields indicated by the existence bitmap subfield as being included may include a MAC address subfield of a multilink device, a link ID information subfield, a BSS parameter change count subfield, a media synchronization delay information subfield, an EML capability subfield, and an MLD capability subfield. In addition, the media synchronization delay information subfield may include MediumSyncDelay related information.

[0352] The common information subfield may include information about multiple links or all links. The common information subfield may include information commonly required by multiple links or all links or commonly applied to multiple links or all links. The link information subfield may include information about the link corresponding to the link information subfield.

[0353] The MediumSyncDelay related information indicates a value to be set as the duration of the MediumSyncDelay and may have a default value. In certain cases, the multi-link device may initialize the duration of the MediumSyncDelay to a default value. In addition, if the multi-link device (non-AP multi-link device) fails to receive the MediumSyncDelay related information from the peer multi-link device (AP multi-link device), the multi-link device may set the duration of the MediumSyncDelay to a default value. When the multi-link device (non-AP multi-link device) receives the MediumSyncDelay related information from the peer multi-link device (AP multi-link device), the duration of the MediumSyncDelay may be set to the value indicated by the received MediumSyncDelay related information.

[0354] exist Fig.25 In the embodiment, the media synchronization delay information subfield may include a media synchronization duration subfield, a media synchronization OFDM ED threshold subfield, and a media synchronization TXOP maximum number subfield.

[0355] The Media Sync Duration subfield may indicate MediumSyncDelay. That is, the Media Sync Duration subfield may indicate a value for setting the MediumSyncDelay timer. For example, the Media Sync Duration subfield may be an 8-bit field. In addition, the Media Sync Duration subfield may indicate a duration in units of 32us. That is, if the Media Sync Duration subfield is set to A, the time indicated by the Media Sync Duration subfield may be A*32us.

[0356] The media synchronization OFDM ED threshold subfield may indicate a CCA threshold when MediumSyncDelay is applied. The CCA threshold indicated by the media synchronization OFDM ED threshold subfield may be a CCA ED threshold. That is, the media synchronization OFDM ED threshold subfield may indicate dot11MSDOFDMEDthreshold. The media synchronization OFDM ED threshold subfield may be a 4-bit field. The CCA threshold indicated by the media synchronization OFDM ED threshold subfield may be a value of -72 plus the value of the media synchronization OFDM ED threshold subfield, and the unit of the CCA threshold may be dBm. Therefore, when the value of the media synchronization OFDM ED threshold subfield is 0 or greater, the CCA threshold indicated by the media synchronization OFDM ED threshold subfield may be a value of -72dBm or greater. In addition, the maximum value of the CCA threshold indicated by the media synchronization OFDM ED threshold subfield may be -62dBm. In this case, the value of the media synchronization OFDM ED threshold subfield may be set within 0 to 10. At this time, as the value of the media synchronization OFDM ED threshold subfield, 11 to 15 may be reserved. That is, the value of the media synchronization OFDM ED threshold subfield may be set to 0 to 10, and at this time, the media synchronization OFDM ED threshold subfield may indicate that the CCA threshold is -72dBm to -62dBm. That is, if the value of the media synchronization OFDM ED threshold subfield is x, the media synchronization OFDM ED threshold subfield may indicate that the CCA threshold is (x-72dBM).

[0357] The maximum number of media synchronization TXOPs subfield may indicate MSD_TXOP_MAX. That is, the maximum number of media synchronization TXOPs subfield may indicate the maximum number of transmission attempts that a station may attempt to transmit during the application of MediumSyncDelay. The maximum number of media synchronization TXOPs subfield may be a 4-bit field. In a specific embodiment, the value of the maximum number of media synchronization TXOPs subfield may be MSD_TXOP_MAX. In another specific embodiment, the value of the maximum number of media synchronization TXOPs subfield may be (MSD_TXOP_MAX+1). In another specific embodiment, the value of the maximum number of media synchronization TXOPs subfield may be (MSD_TXOP_MAX-1). This embodiment may be applied when the value of the maximum number of media synchronization TXOPs subfield is not set to a maximum value. If the value of the maximum number of media synchronization TXOPs subfield is set to a maximum value, for example, if the maximum number of media synchronization TXOPs subfield is a 4-bit field and is set to 15, the maximum number of media synchronization TXOPs subfield may indicate that a station may be allowed to attempt to transmit without being limited by the number of transmission attempts during the application of MediumSyncDelay.

[0358] Fig.26 The multi-link setting process according to an embodiment of the present invention is shown.

[0359] exist Fig.26 In the embodiment, the AP multi-link device includes a first AP AP1, a second AP AP2, and a third AP AP3. The non-AP multi-link device (non-AP MLD) includes a first non-AP station STA1, a second non-AP station STA2, and a third non-AP station STA3. The first AP AP1 and the first non-AP station STA1 operate on a first link link1. In addition, the second AP AP2 and the second non-AP station STA2 operate on a second link link2. In addition, the third AP AP3 operates on a third link link3.

[0360] The first AP AP1 may signal the existence of the AP multi-link device AP MLD and parameters related to the AP multi-link device AP MLD by sending a reduced neighbor report element. The reduced neighbor report element sent by the first AP AP1 may include information about the second AP AP2 or the third AP AP3. The reduced neighbor report element may be included in a beacon frame or a probe response frame.

[0361] In addition, the first non-AP station STA1 that receives the frame including the reduced neighbor report element can identify the AP or AP multi-link device indicated by the reduced neighbor report element. At this time, the first non-AP station STA1 can request the first AP AP1 for information about the AP multi-link device AP MLD or multiple links operated by the AP multi-link device AP MLD by sending a probe request frame including a multi-link element to the first AP AP1. At this time, the multi-link element may include information about the non-AP multi-link device or information about the AP included in the non-AP multi-link device.

[0362] The first AP AP1 may send a probe response frame to the non-AP station STA1 in response to the probe request frame. At this time, the probe response frame may include a multilink element. The multilink element may include information about an AP multilink device or information about an AP included in an AP multilink device AP MLD. Specifically, the multilink element may include information requested by the first non-AP station STA1.

[0363] The first non-AP station STA1 may send an association request frame or a reassociation request frame to the first AP AP1. The association request frame and the reassociation request frame may include a multilink element. At this time, the multilink element may include information about the link for which the non-AP multilink device wants to perform multilink setup. For example, in Fig.25 In the embodiment, the multilink element may include information about the first link link1 and the second link link2.

[0364] The first AP AP1 may send an association response frame or a reassociation response frame to the first non-AP station STA1. At this time, the association response frame and the reassociation response frame may include a multilink element. At this time, the multilink element may include information about the link for which the multilink setup is performed. The link for which the multilink setup is performed may be determined based on the link on which the non-AP multilink device wants to perform the multilink setup. Fig.25 In the multi-link element, the multi-link element may include information about a first link link1 and a second link link2 on which the first non-AP station STA1 wants to perform multi-link setting.

[0365] If the association response frame or the re-association response frame is successfully transmitted, it can be considered that the multilink setting for the link indicated by the multilink element included in the association response frame or the re-association response frame has been successfully performed.

[0366] Fig. 27 The format of the reduced neighbor report element according to an embodiment of the present invention is shown.

[0367] It will be further described Fig.26 The Abbreviated Neighbor Report element described in .

[0368] The station or AP that sends the element is called the reporting station and the reporting AP. In addition, the station or AP indicated by the element is called the reported station or the reported AP. The station or AP that sends the reduced neighbor report element or the multilink element is called the reporting station or the reporting AP. The station or AP indicated by the reduced neighbor report element or the multilink element is called the reported station and the reported AP.

[0369] Reference Fig. 27 (a) of the reduced neighbor report element, the reduced neighbor report element may include an element ID subfield, a length subfield, and one or more neighbor AP information subfields. The element ID subfield may indicate the ID of the element. The element ID subfield of the reduced neighbor report element may indicate the ID of the reduced neighbor report element. The length subfield may indicate the size of the reduced neighbor report element. For example, the length subfield may indicate the length of the reduced neighbor report element excluding the element ID subfield and the length subfield. That is, in Fig. 27 In the embodiment of (a), the length subfield may indicate the length of the neighbor AP information subfield.

[0370] Each of the one or more neighbor AP information fields included in the reduced neighbor report element may be associated with Fig. 27 The neighbor AP information subfield may include a TBTT information header subfield, an operation category subfield, a channel number subfield, and a TBTT information set subfield.

[0371] The TBTT information header subfield can be a 2-octet field. In addition, the format of the TBTT information header subfield can be as follows: Fig. 27 (c) of FIG. 10 . The TBTT information header subfield may include a TBTT information field type subfield, a filtered neighbor AP subfield, a reserved subfield, a TBTT information count subfield, and a TBTT information length subfield. The TBTT information field type subfield may be a 2-bit field, the filtered neighbor AP subfield may be a 1-bit field, the reserved subfield may be a 1-bit field, the TBTT information count subfield may be a 4-bit field, and the TBTT information length subfield may be an 8-bit field.

[0372] The TBTT information field type subfield and the TBTT information length subfield together identify the TBTT information subfield. The value of the TBTT information field type subfield can be set to 0, and 1, 2, and 3 in the TBTT information field type subfield value can be reserved values.

[0373] If the Filter Neighbor AP subfield is not included in the probe response frame sent by the TVHT AP, the Filter Neighbor AP subfield is set to a reserved field. It is reserved unless a Reduced Neighbor Report element is carried in the probe response frame sent by the TVHT AP. If the probe response frame sent by the TVHT AP includes the Filter Neighbor AP subfield and all BSSs of the AP in the Filter Neighbor AP subfield correspond to a specific SSID, the value of the Filter Neighbor AP subfield may be set to 1. Otherwise, the value of the Filter Neighbor AP subfield may be set to 0.

[0374] The TBTT information count subfield may indicate the number of TBTT information subfields included in the neighbor AP information subfield including the TBTT information count subfield. For example, the TBTT information count subfield may be set to a value obtained by subtracting 1 from the number of TBTT information subfields included in the neighbor AP information subfield including the TBTT information count subfield.

[0375] The TBTT information length subfield may indicate the length of each TBTT information subfield included in the neighbor AP information subfield including the TBTT information length subfield. In addition, the TBTT information length subfield may indicate the configuration of each TBTT information subfield included in the neighbor AP information subfield including the TBTT information length subfield. At this time, the TBTT information length subfield may indicate the length and configuration of each TBTT information subfield.

[0376] The TBTT information set subfield may include one or more TBTT information subfields.

[0377] The TBTT information subfield can be as follows Fig. 27 The TBTT information subfield may include a neighbor AP TBTT offset subfield, a BSSID subfield, a short SSID subfield, a BSS parameter subfield, a 20MHz PSD subfield, and an MLD parameter subfield. The size of each subfield may be as follows: Fig. 27 At this time, the TBTT information subfield may be optionally included.

[0378] The Neighbor AP TBTT Offset subfield may indicate an offset obtained by rounding down the interval between the previous TBTT to the next TBTT of the AP sending the Reduced Neighbor Report element to the nearest TU. If the value of the Neighbor AP TBTT Offset subfield is 254, it may indicate that the offset is 254TU or greater. If the value of the Neighbor AP TBTT Offset subfield is 255, it may indicate a situation where the offset value is unknown.

[0379] The BSSID subfield may indicate a BSSID.

[0380] The Short SSID subfield may indicate the SSID. Specifically, the Short SSID subfield may indicate abbreviated SSID information.

[0381] The BSS parameter subfield may indicate information about the BSS. The information about the BSS may include information about BSS operation.

[0382] The 20MHz PSD subfield may indicate the maximum transmission power for the default class in the 20MHz primary channel. At this time, the 20MHz PSD subfield may indicate the maximum transmission power in dBm / MHz. The value of the 20MHz PSD subfield is a signed integer, and the value -128 of the 20MHz PSD subfield is a reserved value. The value 127 of the 20MHz PSD subfield may indicate that there is no limit on the maximum transmission power for the default class. In addition, when the value Y of the 20MHz PSD subfield is between -127 and 126, the 20MHz PSD subfield may indicate that the maximum transmission power for the default class in the MHz primary channel is Y / 2dBM / MHz.

[0383] The TBTT information field configuration indicated by the value of the TBTT information length subfield can be as follows. If the value of the TBTT information length subfield is 1, the TBTT information subfield may include a neighbor AP TBTT offset subfield. If the value of the TBTT information length subfield is 2, the TBTT information subfield may include a neighbor AP TBTT offset subfield and a BSS parameter subfield. If the value of the TBTT information length subfield is 4, the TBTT information subfield may include a neighbor AP TBTT offset subfield and an MLD parameter subfield. If the value of the TBTT information length subfield is 5, the TBTT information subfield may include a neighbor AP TBTT offset subfield and a short SSID subfield. If the value of the TBTT information length subfield is 6, the TBTT information subfield may include a neighbor AP TBTT offset subfield, a short SSID subfield, and a BSS parameter subfield. If the value of the TBTT information length subfield is 7, the TBTT information subfield may include a neighbor AP TBTT offset subfield and a BSSID subfield. If the TBTT information length subfield value is 8, the TBTT information subfield may include the neighbor AP TBTT offset subfield, the BSSID subfield, and the BSS parameter subfield. If the TBTT information length subfield value is 9, the TBTT information subfield may include the neighbor AP TBTT offset subfield, the BSSID subfield, the BSS parameter subfield, and the 20MHz PSD subfield. If the TBTT information length subfield value is 10, the TBTT information subfield may include the neighbor AP TBTT offset subfield, the BSSID subfield, and the MLD parameter subfield. If the TBTT information length subfield value is 11, the TBTT information subfield may include the neighbor AP TBTT offset subfield, the BSSID subfield, and the short SSID subfield. If the TBTT information length subfield value is 12, it may include the TBTT information subfield, the neighbor AP TBTT offset subfield, the BSSID subfield, the short SSID subfield, and the BSS parameter subfield. If the value of the TBTT information length subfield is 13, the TBTT information subfield may include the neighbor AP TBTT offset subfield, BSSID subfield, short SSID subfield, BSS parameter subfield, and 20MHz PSD subfield. If the value of the TBTT information length subfield is 16, the TBTT information subfield may include the neighbor AP TBTT offset subfield, BSSID subfield, short SSID subfield, BSS parameter subfield, 20MHz PSD subfield, and MLD parameter subfield.If the value of the TBTT information length subfield is 17 or greater, the TBTT information subfield may include the neighbor AP TBTT offset subfield, BSSID subfield, short SSID subfield, BSS parameter subfield, 20MHz PSD subfield, and MLD parameterizable subfield in the first 16 octets. The remaining subfields of the TBTT information subfield not previously described may be designated as reserved. That is, when the TBTT information length subfield is 4, 10, 16, or more than 17, the MLD parameter subfield may be included.

[0384] The MLD parameter subfield can be Fig. 27 As shown in (e). The MLD parameter subfield may include an MLD ID subfield, a link ID subfield, a BSS parameter change count subfield, and a reserved subfield. The MLD ID subfield may be an 8-bit field. In addition, the link ID subfield may be a 4-bit field. In addition, the BSS parameter change count subfield may be an 8-bit field. In addition, the reserved subfield may be a 4-bit field.

[0385] The MLD ID subfield may indicate the ID of a multi-link device, such as the ID of an AP multi-link device. The MLD ID subfield may indicate the ID of a multi-link device corresponding to the TBTT information subfield including the MLD ID subfield. The specific setting method of the MLD ID subfield may be as follows: Fig.28 shown.

[0386] The Link ID subfield may indicate the ID of the link corresponding to the reported AP. If the reported AP is not attached to a multi-link device or the reporting AP does not have relevant information, the link ID may be set to 15.

[0387] The BSS parameter change count subfield may indicate a value that is incremented when a critical update occurs in a beacon frame of the reported AP. The value of the BSS parameter change count subfield may be initialized to 0. The value of the BSS parameter change count subfield may be incremented by 1 whenever a critical update occurs to the AP or BSS corresponding to the BSS parameter change count subfield. The critical update may include a predetermined parameter being updated. The predetermined parameter may include an operating parameter. If the reported AP is not attached to a multi-link device or the reporting AP does not have information about the multi-link device to which the reported AP is attached, the value of the BSS parameter change count subfield may be set to 255.

[0388] Fig.28 A method for setting an ID of a multi-link device according to an embodiment of the present invention is shown.

[0389] The ID of a multilink device can be Fig. 27The value indicated by the MLD ID subfield described in. In addition, the MLD ID subfield can be 8 bits. The MLD ID subfield can represent a value from 0 to 255. In an embodiment of the present invention, the reporting AP can represent the AP that sets and sends the MLD ID subfield. In addition, the reported AP can represent the AP indicated by the MLD ID subfield or the TBTT information subfield including the MLD ID subfield.

[0390] According to an embodiment of the present invention, the MLD ID subfield may be set as follows. The MLD ID subfield may indicate the ID of the AP multi-link device to which the reported AP is attached. If the reported AP is attached to the AP multi-link device to which the reporting AP is attached, the MLD ID subfield may be set to 0. If the reported AP is attached to the multi-link device set to which the non-transmission BSSID in the multi-BSSID set to which the reporting AP is attached is attached, the value of the MLD ID subfield may be set to the same value as the value of the BSSID index field of the multiple BSSID index element of the non-transmission BSSID profile corresponding to the non-transmission BSSID. If the reported AP is part of another AP multi-link device and the frame including the MLD ID subfield does not include the multiple BSSID element, the value of the MLD ID subfield may be set to a value greater than 0 and less than 255. In addition, if the reported AP is part of another AP multi-link device and the frame including the MLD ID subfield includes the multiple BSSID element, the value of the MLD ID subfield may be set to a value greater than 2^n-1 and less than 255. At this time, n is the value of the MaxBSSID indicator subfield of the multi-BSSID element. If the reported AP is not part of the multi-link device or the reporting AP does not have information about the multi-link device to which the reported AP is attached, the value of the MLD ID subfield may be set to 255. That is, if the reported AP is attached to the multi-link device to which the reporting AP is attached, the value of the MLD ID subfield may be set to 0. Specifically, if the reported AP is not part of the multi-link device or the reporting AP does not have information about whether the reported AP is attached to the multi-link device, the value of the MLD ID subfield may be set to 255. That is, if the reported AP is attached to the multi-link device to which the reporting AP is attached, the value of the MLD ID subfield may be set to 0.

[0391] exist Fig.28In the embodiment of the present invention, the reporting AP operates on the first link link1. The reporting AP is attached to the first multi-link device, and the reporting AP sends the reduced neighbor report element and the MLD ID subfield. In addition, the first multi-link device MLD1 operates on the first link link1, the second link link2, and the third link link3. At this time, the reporting AP sets the value of the MLD ID subfield corresponding to the AP operating in each of the second link link2 and the third link link3 to 0.

[0392] In addition, the reporting AP may send the multi-BSSID element together with the reduced neighbor report element. In another specific embodiment, the reporting AP may not send the multi-BSSID element. In this case, the situation where the reporting AP sends the multi-BSSID element may be a situation where the reporting AP is attached to a multi-BSSID set. In addition, the situation where the reporting AP does not send the multi-BSSID element may be a situation where the reporting AP is not attached to a multi-BSSID set.

[0393] According to an embodiment of the present invention, when the reported AP is included in the multi-BSSID set to which the reporting AP is attached, the value of the MLD ID subfield may be set to the BSSID index of the multi-BSSID set. In addition, when the reported AP is attached to a multi-link device to which an AP in the multi-BSSID set to which the reporting AP is attached is attached, the value of the MLD ID subfield may be set to the BSSID index of the AP attached to the multi-BSSID set. If the reported AP is attached to a multi-link device to which an AP of a non-transmission BSSID in the multi-BSSID set to which the reported AP is attached is attached, the value of the MLD ID subfield may be set to the BSSID index of the reported AP.

[0394] The multi-BSSID set to which the reporting AP is attached may include an AP operating on the first link link1 and attached to the second multi-link device MLD2. The second multi-link device MLD2 may include an AP operating on the first link link1 and an AP operating on the second link link2. The reporting AP may set the value of the MLD ID subfield corresponding to the AP attached to the second multi-link device MLD2 and operating on the first link link1 and the AP attached to the second multi-link device MLD2 and operating on the second link link2 to the BSSID index of the reported AP. This is because the AP of the second multi-link device MLD2 operating on the first link link1 and the AP of the second multi-link device MLD2 operating on the second link link2 are attached to the same multi-BSSID set as the reporting AP or to a multi-link device set included in the multi-BSSID set to which the reporting AP is attached.

[0395] When the reporting AP sends a multi-BSSID element, if the reported AP is not affiliated with a multi-link device to which the reporting AP is affiliated, the reported AP is not affiliated with a multi-BSSID set to which the reporting AP is affiliated, and the reported AP is not affiliated with a multi-link device to which an AP in the multi-BSSID set to which the reporting AP is affiliated is affiliated, the value of the MLD ID subfield may be set to a value greater than (2^n-1) and less than a predetermined value.

[0396] In addition, when the reporting AP sends a multi-BSSID element, if the reported AP is not attached to a multi-link device to which the reporting AP is attached, the reported AP is not attached to a multi-BSSID set to which the reporting AP is attached, and the reported AP is not attached to a multi-link device to which an AP in the multi-BSSID set to which the reporting AP is attached is attached, then the value of the MLD ID subfield may be set to a value greater than (2^n-1) and less than a predetermined value. In addition, this may be limited to the case where the reported AP is attached to MLD. The above-mentioned predetermined value may be the maximum value that the MLD ID subfield can represent. The above-mentioned predetermined value may be 255. In addition, n may be a MaxBSSID indicator value corresponding to the multi-BSSID set including the reporting AP.

[0397] exist Fig.28 , the third multi-link device MLD3 may include an AP operating on the first link link1 and an AP operating on the second link link2. In addition, the AP affiliated with the third multi-link device MLD3 and operating on the first link link1 may not be affiliated with the multi-BSSID set to which the reporting AP is affiliated. At this time, the value of the MLDID subfield of the AP affiliated with the third multi-link device MLD3 and operating on the first link link1 and the AP affiliated with the third multi-link device MLD3 and operating on the second link link2 may be set to a value greater than 2^n-1 and less than 255. This is because the AP affiliated with the third multi-link device MLD3 and operating on the first link link1 and the AP affiliated with the third multi-link device MLD3 and operating on the second link link2 are not affiliated with the multi-link device to which the reporting AP is affiliated, and these two APs are not included in the multi-link devices to which the APs in the multi-BSSID set to which the reporting AP is affiliated are affiliated.

[0398] If the reporting AP does not send a multi-BSSID element and if the reported AP is not attached to a multi-link device to which the reporting AP is attached, the value of the MLD ID subfield may be set to a value greater than 0 and less than a predetermined value. In addition, this may be limited to the case where the reported AP is attached to a multi-link device. In addition, the predetermined value may be the maximum value that the MLD ID subfield can represent. The predetermined value may be 255.

[0399] In addition, if 1) the reported AP is not attached to the multi-link device, or 2) the reporting AP does not have information on whether the reported AP is attached to the multi-link device, or 3) the reporting AP does not have the above-mentioned information for setting the value of the MLD ID subfield, the reporting AP may set the value of the MLD ID subfield to a predetermined value. In another specific embodiment, if 1) the reported AP is not attached to the multi-link device, or 2) the reporting AP does not have information on whether the reported AP is attached to the multi-link device, or 3) the reporting AP does not have the above-mentioned information for setting the value of the MLD ID subfield, the reporting AP may set the value of the MLD ID subfield to a predetermined value or greater. The predetermined value may be a maximum value that the MLD ID subfield may represent. The predetermined value may be 255.

[0400] exist Fig.28 In FIG. 1 , the fourth AP AP4 operates on the first link link1. At this time, the fourth AP AP4 is not attached to any multi-link device. Therefore, the reporting AP may set the value of the MLD ID subfield corresponding to the fourth AP AP4 to 255.

[0401] The station determines from which BSS the frame is sent based on the MAC address field of the MAC header of the received frame. Specifically, the station can determine whether the received frame is sent from the AP associated with the station or from an AP of multiple BSSIDs to which the AP associated with the station is attached based on the MAC address field of the MAC header of the received frame. In a specific embodiment, the station can determine whether the received frame is sent from the AP associated with the station or from an AP of multiple BSSIDs to which the AP associated with the station is attached based on the TA field of the MAC header of the received frame. At this time, if the TA field of the frame received by the station indicates the MAC address of the AP associated with the station or the MAC address of the AP of the multiple BSSID set to which the AP associated with the station is attached, the station can determine whether the received frame is sent from the AP associated with the station or the AP of the multiple BSSID set to which the AP associated with the station is attached. If the TA field of the frame received by the station does not indicate the MAC address of the AP associated with the station and the MAC address of the AP affiliated to the multi-BSSID set to which the AP associated with the station belongs, the station can determine that the received frame is sent from the AP associated with the station and the AP affiliated to the multi-BSSID set to which the AP associated with the station belongs.

[0402] The station can determine to which AP the frame is sent based on the MAC address field of the MAC header of the received frame. In a specific embodiment, the station can determine whether the received frame is sent to the AP associated with the station or to the AP of the multiple BSSIDs to which the AP associated with the station is attached based on the RA field of the MAC header of the frame. At this time, if the RA field of the frame received by the station indicates the MAC address of the AP associated with the station or the MAC address of the AP of the multiple BSSID set to which the AP associated with the station is attached, the station can determine that the received frame is sent to the AP associated with the station or the AP of the multiple BSSID set to which the AP associated with the station is attached. If the RA field of the frame received by the station does not indicate the MAC address of the AP associated with the station and the MAC address of the AP of the multiple BSSID set to which the AP associated with the station is attached, the station can determine that the received frame is sent to the AP associated with the station and the AP of the multiple BSSID set to which the AP associated with the station is attached.

[0403] The station may determine whether the frame is an Inter-BSS frame based on the MAC address field of the MAC header of the received frame. The MAC address field may include at least any one of the RA field, the TA field, and the BSSID field. If the RA field, the TA field, and the BSSID field of the frame received by the station do not all indicate the MAC address of the AP associated with the station and the MAC address of the AP attached to the multi-BSSID set to which the AP associated with the station is attached, the station may determine the received frame to be an Inter-BSS frame. If at least any one of the RA field, the TA field, and the BSSID field of the frame received by the station indicates the MAC address of the AP associated with the station and the MAC address of the AP attached to the multi-BSSID set to which the AP associated with the station is attached, the station may determine the received frame to be an Intra-BSS frame.

[0404] In these embodiments, the BSSID may be used instead of the AP's MAC address.

[0405] If the BSS color included in the preamble of the PPDU received by the station is the same as the BSS color of the BSS to which the station is attached, and the preamble of the PPDU received by the station indicates that it is used for downlink transmission, the station can determine that the received PPDU is sent by the AP associated with the station or an AP attached to the multi-BSSID set to which the AP associated with the station is attached. If the BSS color included in the preamble of the PPDU received by the station is different from the BSS color of the BSS to which the station is attached, or if the preamble of the PPDU received by the station does not indicate that it is used for downlink transmission, the station can determine that the received PPDU is not sent by the AP associated with the station or an AP attached to the multi-BSSID set to which the AP associated with the station is attached.

[0406] A multi-BSSID set may be a set of multiple BSSs, in which information about the BSS may be signaled by a (single) beacon frame or a (single) probe response frame. Specifically, a set of BSSIDs indicated by a multi-BSSID element may be referred to as a multi-BSSID set. In addition, a TIM element included in a beacon frame or a TIM frame may indicate a cached frame in a plurality of BSSIDs included in a multi-BSSID set. In addition, a (single) beacon frame or a (single) probe response frame may include a multi-BSSID element. The multi-BSSID element may signal information about multiple BSSs. The BSSID of the BSS to which the above-mentioned beacon frame or probe response frame is sent is referred to as a transmitted BSSID. In a multi-BSSID set, the remaining BSSIDs except the transmitted BSSID may be referred to as non-transmitted BSSIDs. In addition, in a BSS corresponding to a non-transmitted BSSID, a beacon frame or a probe response frame may not occur.

[0407] As described above, the maximum number of BSSIDs that a multi-BSSID set can include may be 2^n. At this time, n may be a value signaled in a multi-BSSID element. For example, n may be a value indicated by a MaxBSSID indicator included in a multi-BSSID element. A station receiving a multi-BSSID element may determine a MAC address or BSSID of an AP included in a multi-BSSID set based on the received multi-BSSID element. In addition, each of a plurality of BSSID indexes may be mapped to each BSSID included in a multi-BSSID set. Therefore, a BSSID included in a multi-BSSID set may be identified by a BSSID index. The maximum value of the MaxBSSID indicator may be 8.

[0408] However, in the above-described embodiments of the method for setting the MLD ID subfield, there may be a case where the value of the MLD ID subfield cannot be set.

[0409] In the above embodiment, when at least any one of the predetermined conditions is met, the reporting AP may set the value of the MLD ID subfield to a predetermined value. In another specific embodiment, when the predetermined condition is met, the reporting AP may set the value of the MLD ID subfield to a predetermined value or greater. The predetermined value may be the maximum value that the MLD ID subfield can represent. At this time, the predetermined value may be 255. The predetermined condition may include at least one of the following: 1) the reported AP is not attached to a multi-link device, 2) the reporting AP does not have information about whether the reported AP is attached to a multi-link device, and 3) the reporting AP does not have the above-mentioned information for setting the value of the MLD ID subfield. In addition, the predetermined condition may include: when the value of the MaxBSSID indicator field corresponding to the reporting AP is the maximum value, the reported AP is not included in the multi-link device to which the AP of the multi-BSSID set to which the reporting AP is attached is not included. The condition may be that the reporting AP sends a multi-BSSID element. The maximum value of the MaxBSSID indicator field may be 8.

[0410] When the reporting AP sends a multi-BSSID element, if the reported AP is an AP included in the multi-BSSID set including the reporting AP, or the reported AP is attached to a multi-link device to which the AP in the multi-BSSID set including the reporting AP is attached, the MLD ID subfield may be set to the BSSID index of the AP included in the multi-BSSID set. If the value of the MaxBSSID indicator subfield is 8, the maximum number of BSSIDs that the multi-BSSID set may include may be 2^8=256. Therefore, according to the above conditions, there may be no value greater than 2^n-1 and less than 255.

[0411] In addition, when the value of the MaxBSSID indicator subfield corresponding to the reporting AP is the maximum value, the reporting AP may not be able to set the value of the MLD ID subfield even if the reported AP is attached to a multi-link device to which an AP of the multi-BSSID set to which the reporting AP is attached is attached. For example, the reporting AP cannot indicate a multi-link device with a BSSID index of 255. This is because, according to the previously described embodiment, the value of the MLD ID subfield can be set to 255. Therefore, when the value of the MLD ID subfield is 255, it is difficult to distinguish whether it is 255 set based on the BSSID index or 255 set based on a predetermined value.

[0412] Therefore, the condition for setting the value of the MLD ID subfield to a predetermined value may also include: when the value of the MaxBSSID indicator subfield corresponding to the reporting AP is the maximum value, the reported AP is attached to a multi-link device to which an AP in the multi-BSSID set to which the reporting AP is attached is attached. In another specific embodiment, the use of 255 as a BSSID index in the multi-BSSID set may not be allowed.

[0413] In addition, when following the previously described embodiments, regardless of whether the reporting AP sends a multi-BSSID element, it may be difficult for the reporting AP to set the value of the MLD ID subfield. For example, when the reporting AP indicates information about a large number of APs, it may be difficult for the reporting AP to set the value of the MLD ID subfield. Since the number of reported APs is greater than the number of IDs of multi-link devices that can be set, the reported AP may not be identified by the ID of the multi-link device. For example, when the reporting AP sends a multi-BSSID element and the reporting AP passes information about more than (254-2^n+1) APs, the reported AP may not be identified by the ID of a limited range of multi-link devices. When the reporting AP does not send a multi-BSSID element and the reporting AP passes information about more than (254-1+1) APs, the reported AP may not be identified by a limited range of IDs. The conditions for setting the value of the MLD ID subfield to a predetermined value may also include: a situation where the reported AP cannot be identified by a limited range of IDs.

[0414] In order to solve the above problem, the size of the MLD ID subfield may be set to be greater than 8 bits. In this case, the predetermined value may be the maximum value that the MLD ID subfield may indicate. That is, if the size of the MLD ID subfield is N bits, the predetermined value may be 2^N-1. For example, the size of the MLD ID subfield may be 9 bits, and the predetermined value may be 511. As another example, the size of the MLD ID subfield may be 16 bits, and the predetermined value may be 65535.

[0415] Fig.29 and Fig.30 A method for allocating AIDs to non-AP stations attached to a multi-link device according to an embodiment of the present invention is shown.

[0416] According to an embodiment of the present invention, one AID (Association ID) may be allocated to a multi-link device. That is, the AIDs of stations included in one multi-link device may be the same.

[0417] The AID allocation may be performed by the AP. For example, the AID allocated by the AP may be sent to the non-AP STA. The non-AP STA may recognize that the AID received from the AP is the AID corresponding to itself. The non-AP station that receives the subfield containing the AID value allocated to the non-AP station may recognize that the subfield containing the AID value allocated to the non-AP station indicates the non-AP station.

[0418] The AID allocated to the non-AP station may be included in the association response frame or the reassociation response frame. If the AP performs multilink setup after allocating the AID to the non-AP station, the AID allocated to the non-AP station may be allocated to a multilink device to which the non-AP station is attached.

[0419] The AID or information about the AID may be included in the preamble of the PPDU. At this time, the PPDU preamble may use the AID to indicate that the intended recipient of the PPDU is a non-AP station corresponding to the AID. The PPDU preamble may use the AID to indicate that the sender of the PPDU is a non-AP station corresponding to the AID. In addition, as described above, the AID may be used to indicate traffic. The frame may use the AID to indicate that the station corresponding to the AID is the recipient of the frame. For example, a trigger frame may use the AID to indicate the station triggered by the trigger frame.

[0420] The AID assigned to the multilink device may not be allowed to be assigned to other stations or other multilink devices. In a specific embodiment, the AID assigned to the multilink device may not be allowed to be assigned to a station or multilink device operating on a non-operating link among the links used by the multilink device.

[0421] exist Fig.29 In the example, the first multi-link device MLD1 operates on the first link Link1 and the second link Link2. In addition, the second multi-link device MLD2 operates on the third link Link3 and the fourth link Link4. At this time, X is assigned as the AID of the first multi-link device MLD1. Therefore, as the AID of the second multi-link device MLD2, X is not allowed to be assigned, but Y is assigned.

[0422] In a specific embodiment of the present invention, the AP multi-link device may reallocate the AID assigned to a certain multi-link device to another station or another multi-link device. When a predetermined condition is met, the AP multi-link device may reallocate the AID assigned to a certain multi-link device to another station or another multi-link device. At this time, the predetermined condition may include: the multi-link devices or stations to which one AID is commonly assigned operate on links different from each other. That is, the predetermined condition may include: the multi-link devices or stations to which one AID is commonly assigned operate on links that do not overlap with each other. At this time, a station or multiple multi-link devices operating on one link may not be allowed to be assigned one AID. In another specific embodiment, it may include: the multi-link devices or stations to which one AID is commonly assigned operate on channels that do not overlap with each other.

[0423] exist Fig.30 In (a), the first multi-link device MLD1 operates on the first link Link1 and the second link Link2. The AP multi-link device allocates X as the AID of the station of the first multi-link device MLD1. At this time, the AP multi-link device may allocate X as the AID of the first station STA1 which is not affiliated with the first multi-link device MLD1 and operates on the third link Link3 instead of the first link Link1 and the second link Link2.

[0424] In such an embodiment, when a frame includes information about multiple links, one AID assigned to multiple multi-link devices or stations may cause confusion. To prevent this, information sent on a certain link may be applied to the stations or multi-link devices operating on the link. For example, information sent on a first link may be applied to the station or multi-link device with AID X operating on the first link, but not to the station or multi-link device with AID X operating on the second link.

[0425] exist Fig.30 In (b), a beacon frame including a TIM is sent on each of the first link link1 and the second link link2. At this time, the TIMs sent on the first link Link1 and the second link Link2 both indicate that traffic corresponding to AID X is cached. The TIM sent on the first link Link1 indicates that traffic for the multi-link device MLD1 operating on the first link Link1 is cached, and the TIM sent on the second link Link2 indicates that traffic for the station STA1 operating on the second link Link2 is cached.

[0426] Will pass Figure 31 to Figure 33 Describes the TID to link mapping negotiation.

[0427] Fig.31is a diagram illustrating TID-to-link mapping negotiation according to an embodiment of the present invention.

[0428] As mentioned above, the default mapping may be applied to a link for which TID-to-link mapping has not been performed. In addition, when the TID-to-link mapping on a link for which TID-to-link mapping negotiation has been completed is torn down, the default mapping may be reapplied to the link.

[0429] The TID to link mapping negotiation may be performed by a TID to link mapping request and a TID to link mapping response. Specifically, the multilink device may perform the TID to link mapping request by sending a frame containing a TID to link mapping element. At this time, the frame may include an association request frame, a reassociation request frame, and a TID to link mapping request frame. Therefore, a non-AP station or a non-AP multilink device may request TID to link mapping by sending an association request frame, a reassociation request frame, or a TID to link mapping request frame. An AP or an AP multilink device may request TID to link mapping by sending a TID to link mapping request frame. A multilink device that receives a TID to link mapping request may perform a TID to link mapping response by sending a frame containing a TID to link mapping element. At this time, the frame may include an association response frame, a reassociation response frame, and a TID to link mapping response frame. Therefore, an AP or an AP multilink device may respond to a TID to link mapping request by sending an association response frame, a reassociation response frame, or a TID to link mapping request frame. A non-AP station or a non-AP multilink device may respond to a TID to link mapping request by sending a TID to link mapping response frame.

[0430] The multi-link device may initiate TID-to-link mapping by sending a TID-to-link mapping request. At this time, the multi-link device may request a default mapping by sending a frame including a TID-to-link mapping element. The multi-link device that has received the TID-to-link mapping request may accept the TID-to-link mapping by sending a TID-to-link mapping response to the TID-to-link mapping request. At this time, the multi-link device that has received the TID-to-link mapping request may accept the TID-to-link mapping by sending a frame that does not include a TID-to-link mapping element. In another specific embodiment, the multi-link device that has received the TID-to-link mapping request may accept the TID-to-link mapping by sending a frame including a TID-to-link mapping element having the same content as the TID-to-link mapping request content received from the non-AP multi-link device.

[0431] In addition, the multi-link device that receives the TID-to-link mapping request may reject the TID-to-link mapping by sending a TID-to-link mapping response to the TID-to-link mapping request. At this time, the multi-link device that receives the TID-to-link mapping request may reject the TID-to-link mapping by sending a frame that does not include a TID-to-link mapping element. In another specific embodiment, the multi-link device that receives the TID-to-link mapping request may reject the TID-to-link mapping by sending a frame that includes a TID-to-link mapping element having content different from that of the received TID-to-link mapping element. If the TID-to-link mapping is rejected, a default mapping may be applied to the link.

[0432] In these embodiments, the frames for TID to link mapping request and response sent by the multilink device may include at least any one of the association request frame, association response frame, reassociation request frame, reassociation response frame, TID to link mapping request frame, and TID to link mapping response frame as described above. Specifically, the multilink device that receives the TID to link mapping request may send a TID to link mapping response frame for the TID to link mapping request. At this time, the multilink device that receives the TID to link mapping request may accept or reject the TID to link mapping request by inserting a status code in the TID to link mapping response frame. Specifically, the multilink device that receives the TID to link mapping request may accept the TID to link mapping request by setting the status code of the TID to link mapping response frame to SUCCESS. In addition, the multilink device that receives the TID to link mapping request may reject the TID to link mapping request by setting the status code of the TID to link mapping response frame to REJECT or DENIED_TID_TO_LINK_MAPPING. In addition, the multi-link device that receives the TID to link mapping request may reject the TID to link mapping request by setting the status code of the TID to link mapping response frame to PREFERRED_TID_TO_LINK_MAPPING_SUGGESTED. At this time, the multi-link device that receives the TID to link mapping request may reject the TID to link mapping request while suggesting a preferred TID to link mapping. In addition, the multi-link device that receives the TID to link mapping request may reject the TID to link mapping request by sending a TID to link mapping rejection frame.

[0433] The TID to link mapping element included in the TID to link matching request indicates the TID to link mapping that is the object of the TID to link mapping request. In addition, the TID to link mapping element sent when the TID to link mapping is accepted may indicate the accepted TID to link mapping. In addition, the TID to link mapping element sent when the TID to link mapping is rejected may indicate a newly proposed TID to link mapping.

[0434] If the TID to link mapping request is accepted, the TID to link mapping included in the TID to link mapping request is set on the link that is the object of the TID to link mapping. In addition, if the TID to link mapping request is rejected, a default mapping may be applied to the link that is the object of the TID to link mapping.

[0435] In addition, for TID to link mapping negotiation, the TID to link mapping request frame and the TID to link mapping response frame may include a dialogue token. The dialogue token maps the TID to link mapping request frame with the TID to link mapping response frame. Specifically, if the value of the dialogue token of the TID to link mapping request frame is the same as the value of the dialogue token of the TID to link mapping response frame, the TID to link mapping response frame is sent as a response to the TID to link mapping request frame. Therefore, when the multi-link device that receives the TID to link mapping request frame sends the TID to link mapping response frame, the multi-link device may set the dialogue token of the TID to link mapping response frame to the value of the dialogue token of the TID to link mapping request frame. If the multi-link device sends the TID to link mapping response frame without receiving the TID to link mapping request frame, the multi-link device may set the dialogue token value of the TID to link mapping response frame to a predetermined value. At this time, the predetermined value may be 0. That is, when the multi-link device sends an unsolicited TID to link mapping response frame, the multi-link device may set the conversation token value of the TID to link mapping response frame to a predetermined value. The field indicating the conversation token in the TID to link mapping request frame and the TID to link mapping response frame may be a 1-octet field. The value of the conversation token may be any value from 0 to 255.

[0436] When the capabilities of the multilink device support TID to link mapping, the multilink device may perform TID to link mapping. In addition, depending on the capabilities of the multilink device, the range in which the multilink device can perform TID to link mapping may be different. For example, depending on the capabilities of the multilink device, the number of TIDs that the multilink device can map to links or the number of combinations of TID and link mapping that can be applied may be different. The capabilities of the multilink device may indicate whether the multilink device can map all TIDs to the same link set. In addition, the capabilities of the multilink device may indicate how many link sets the multilink device can map TIDs to.

[0437] exist Fig.31 In the embodiment of the present invention, the AP multi-link device AP ML includes a first AP AP1, a second AP AP2, and a third AP AP3. The non-AP multi-link device (non-AP MLD) includes a first non-AP station (non-AP STA1) and a second non-AP station (non-AP STA2). The non-AP multi-link device (non-AP MLD) sends an association request frame including a TID-to-link mapping element to the AP multi-link device AP ML. The AP multi-link device AP ML may accept or reject the TID-to-link mapping corresponding to the TID-to-link mapping element by sending an association response frame including a TID-to-link mapping element to the non-AP multi-link device (non-AP MLD). In addition, the non-AP multi-link device (non-AP MLD) may renegotiate the TID-to-link mapping by sending a TID-to-link mapping request frame to the AP multi-link device AP ML. At this time, the AP multi-link device AP ML may accept or reject the TID-to-link mapping corresponding to the TID-to-link mapping element by sending a TID-to-link mapping response frame to the non-AP multi-link device (non-AP MLD).

[0438] Fig.32 FIG. 1 shows a TID-to-link mapping negotiation in which an AP multi-link device sends a TID-to-link mapping request according to an embodiment of the present invention.

[0439] The AP multi-link device may send a TID to link mapping request through an association response frame, a re-association response frame, and a TID to link mapping request frame. Specifically, the AP multi-link device may initiate TID to link mapping negotiation through an association response frame, a re-association response frame, and a TID to link mapping request frame. At this time, the AP multi-link device may include a TID to link mapping element in the association response frame, the re-association response frame, and the TID to link mapping request frame. Specifically, the AP multi-link device may initiate TID to link mapping negotiation by including a TID to link mapping element in the association response frame, the re-association response frame, and the TID to link mapping request frame. This may be because the TID to link mapping request sent by the non-AP multi-link device may be in a form that the AP multi-link device does not expect, and the non-AP multi-link device may not send a TID to link mapping request. In addition, the AP multi-link device may understand the entire network situation more easily than the non-AP multi-link device, so that the TID to link mapping can be effectively determined. At this time, the AP multi-link device may first send an association response frame or a re-association response frame before completing the TID to link mapping negotiation to complete the multi-link setting and resetting. If the non-AP multi-link device that received the TID-to-link mapping request sends a TID-to-link mapping response, the TID-to-link mapping negotiation is successfully completed.

[0440] The case where the AP multi-link device can send a TID to link mapping request through an association response frame and a re-association response frame may be limited. Specifically, if the association request frame does not request TID to link mapping, the AP multi-link device may send a TID to link mapping request through an association response frame. If the association request frame does not include a TID to link mapping element, the AP multi-link device may determine that the association request frame does not request TID to link mapping. In addition, if the re-association request frame does not request TID to link mapping, the AP multi-link device may send a TID to link mapping request through a re-association response frame. If the re-association request frame does not include a TID to link mapping element, the AP multi-link device may determine that the re-association request frame does not request TID to link mapping. If the association request frame sent by the non-AP multi-link device does not include a TID to link mapping element, the non-AP multi-link device may determine that the association response frame received as a response to the association request frame and including a TID to link mapping element requests TID to link mapping. If the reassociation request frame sent by the non-AP multi-link device does not include a TID-to-link mapping element, the non-AP multi-link device may determine that the reassociation response frame received as a response to the reassociation request frame and including the TID-to-link mapping element requests TID-to-link mapping. This is because, in these embodiments, when the association request frame includes the TID-to-link mapping element and the association response frame includes the TID-to-link mapping element, the non-AP multi-link device may be confused about the intention of the association response frame to include the TID-to-link mapping element. This also applies to the reassociation request frame.

[0441] In addition, in these embodiments, the AP multi-link device may not determine that the TID to link mapping has been successfully completed until it receives a TID to link mapping response from a non-AP multi-link device. Therefore, the AP multi-link device may operate according to the default mapping until it receives a TID to link mapping response from a non-AP multi-link device. In addition, even if the AP multi-link device receives an ACK for an association response frame or a re-association response frame, the AP multi-link device may not determine that the TID to link mapping has been successfully completed.

[0442] According to the above embodiment, the non-AP multi-link device may respond to the TID to link mapping request sent by the AP multi-link device through the association frame or the reassociation frame. However, it is necessary for the non-AP multi-link device to indicate that it is responding to the TID to link mapping request sent by the AP multi-link device through the association frame or the reassociation frame. The non-AP multi-link device may send a TID to link mapping response as a response frame to the association response frame requesting TID to link mapping or the reassociation response frame requesting TID to link mapping. In addition, the non-AP multi-link device may set the conversation token value of the TID to link mapping response to be the same as the conversation token value included in the association response frame requesting TID to link mapping or the reassociation response frame requesting TID to link mapping. However, the association response frame requesting TID to link mapping and the reassociation response frame requesting TID to link mapping may not include a conversation token.

[0443] Therefore, the TID to link mapping element may include a response indication field indicating that it is a response to the TID to link mapping request. At this time, the response indication field may be included in the TID to link mapping control field as described above. Specifically, the response indication field may be included in the reserved field of the TID to link mapping control field as described above. For example, the response indication field may be any one of the fourth bit B3 to the eighth bit B8 of the TID to link mapping control field. The multi-link device that receives the TID to link element may determine whether the TID to link mapping element requests TID to link mapping based on the response indication field.

[0444] Since the non-AP multi-link device sends a TID to link mapping response frame in response to an association request frame or a re-association request frame, it is necessary for the AP multi-link device to distinguish which frame the TID to link mapping response frame is a response to. Specifically, when the non-AP multi-link device sends a TID to link mapping response frame in response to an association request frame or a re-association request frame, the non-AP multi-link device may set the value of the conversation token in the TID to link mapping response frame to a random value. In addition, if the value of the conversation token in the TID to link mapping response frame is the same as the value of the conversation token in the TID to link mapping request frame sent by the AP multi-link device, then for the AP multi-link device, the TID to link mapping response frame may be a response to the TID to link mapping request frame. In addition, if the value of the conversation token in the TID to link mapping response frame is different from the value of the conversation token in the TID to link mapping request frame sent by the AP multi-link device, then for the AP multi-link device, the TID to link mapping response frame may be a response to the association request frame or the re-association request frame.

[0445] In another specific embodiment, when the AP multi-link device sends a TID-to-link mapping request through an association response frame or a re-association response frame, the value of the conversation token in the TID-to-link mapping response frame sent in response to the TID-to-link mapping request may be set to a predetermined value. At this time, the predetermined value may be 0, 1, or 255. When the AP multi-link device sends a TID-to-link mapping request through an association frame or a re-association frame and receives a TID-to-link mapping response frame in which the value of the conversation token is the predetermined value, the AP multi-link device may determine that the received TID-to-link mapping response frame is a response to the sent TID-to-link mapping request.

[0446] In another specific embodiment, when the AP multi-link device sends a TID to link mapping request through an association response frame or a re-association response frame, the status code of the TID to link mapping response frame sent in response to the TID to link mapping request may be a predetermined value. At this time, the predetermined value of the status code may be different from the value of the status code of the TID to link mapping response frame sent in response to the TID to link mapping request sent by the multi-link device through a frame other than the association frame and the re-association frame. Thus, based on the status code of the received TID to link mapping response frame, the AP multi-link device may determine whether the received TID to link mapping response frame is a response to the TID to link mapping request sent by the AP multi-link device through the association response frame or the re-association response frame. Specifically, if the status code of the received TID to link mapping response frame is a predetermined value, the AP multi-link device may determine that the received TID to link mapping response frame is a response to the TID to link mapping request sent by the AP multi-link device through the association response frame or the re-association response frame.

[0447] In another specific embodiment, the AP multi-link device may determine whether the received TID to link mapping response frame is a response to a TID to link mapping request sent by the AP multi-link device through an association response frame or a re-association response frame based on the value of the Link Mapping field corresponding to the TID of the received TID to link mapping response frame. Specifically, if the value of the Link Mapping field corresponding to the TID of the received TID to link mapping response frame is the same as the value of the Link Mapping field corresponding to the TID of the TID to link mapping request sent by the AP multi-link device through an association response frame or a re-association response frame, the AP multi-link device may determine that the received TID to link mapping response frame is a response to the TID to link mapping request sent by the AP multi-link device through an association response frame or a re-association response frame. Specifically, the received TID to link mapping response frame may include Link Mapping fields for multiple TIDs. At this time, if the values ​​of all link mapping fields included in the TID to link mapping response frame are the same as the values ​​of all link mapping fields in the TID to link mapping request sent by the AP multi-link device through the association response frame or the re-association response frame, the AP multi-link device may determine that the received TID to link mapping response frame is a response to the TID to link mapping request sent by the AP multi-link device through the association response frame or the re-association response frame. If the value of the link mapping field corresponding to the TID of the TID to link mapping response frame received by the AP multi-link device is different from the value of the link mapping field corresponding to the TID of the TID to link mapping request sent by the AP multi-link device through the association response frame or the re-association response frame, the AP multi-link device may not send an ACK for the received TID to link mapping response frame. In addition, when the link mapping field corresponding to the TID of the TID-to-link mapping response frame received by the AP multi-link device includes at least any one of the values ​​of the link mapping field corresponding to the TID of the link mapping request sent by the AP multi-link device through the association response frame or the re-association response frame, the AP multi-link device may not send an ACK for the received TID-to-link mapping response frame. In addition, when the TID-to-link mapping response frame received by the AP multi-link device does not include any one of the link mapping fields corresponding to the TID of the TID-to-link mapping request sent by the AP multi-link device through the association response frame, or the value of the link mapping field of the TID-to-link mapping response frame received by the multi-link device is different from the value of the link mapping field corresponding to the TID of the TID-to-link mapping request sent through the association response frame or the re-association response frame, the AP multi-link device may not send an ACK for the received TID-to-link mapping response frame. The above embodiment is also applicable to the embodiment in which the TID-to-link mapping request is not sent through the association response frame or the re-association response frame.

[0448] exist Fig.32 In the embodiment of the present invention, the AP multi-link device AP MLD includes a first AP AP1, a second AP AP2, and a third AP AP3. The non-AP multi-link device (non-AP MLD) includes a first non-AP station (non-AP STA1) and a second non-AP station (non-AP STA2). The non-AP multi-link device (non-AP MLD) sends an association request frame not including a TID-to-link mapping element to the AP multi-link device AP ML. The AP multi-link device AP ML requests a TID-to-link mapping corresponding to the TID-to-link mapping element by sending an association response frame including a TID-to-link mapping element to the non-AP multi-link device (non-AP MLD). At this time, the non-AP multi-link device (non-AP MLD) accepts the TID-to-link mapping request by sending a TID-to-link mapping response frame to the AP multi-link device AP ML.

[0449] Fig.33 TID-to-link mapping negotiation is shown when a link set for which TID-to-link mapping is requested is different from a link set set by a TID-to-link mapping response according to an embodiment of the present invention.

[0450] The link set for which TID-to-link mapping is requested in the association request frame or the reassociation request frame may be different from the link set for which TID-to-link mapping is to be set in the association response frame or the reassociation response frame. For example, TID-to-link mapping may be requested for three links in the association request frame or the reassociation request frame, and TID-to-link mapping may be set for two links in the association response frame or the reassociation response frame. In addition, the link sets being different from each other may include a case where the settings for the link sets are different. Specifically, the settings for the link sets being different may include a case where the operating channels of the link sets are different. In addition, the link sets being different from each other may include a case where the configurations of the link sets are different from each other.

[0451] exist Fig.31 In some embodiments, when the AP multi-link device receives an association request frame or a re-association request frame including a TID-to-link mapping element, the AP multi-link device may set up the multi-link by sending an association response frame or a re-association response frame that does not include a TID-to-link mapping element. However, as described above, the link set for which TID-to-link mapping is requested in the association request frame or the re-association request frame may be different from the link set for which TID-to-link mapping is to be set in the association response frame or the re-association response frame.

[0452] Therefore, in another embodiment of the present invention, when the AP multi-link device receives an association request frame or a re-association request frame including a TID to link mapping element, and wants to set a link set different from the link set of the multi-link to be set by the association request frame or the re-association request frame, the AP multi-link device may send an association response frame or a re-association response frame that does not include a TID to link mapping element. Thus, the AP multi-link device may reject the TID to link mapping. At this time, the AP multi-link device and the non-AP multi-link device may apply the default mapping.

[0453] When an AP multi-link device receives an association request frame or a re-association request frame including a TID-to-link mapping element, and sends an association response frame or a re-association response frame for setting a link set different from the link set of the multi-link to be set by the association request frame or the re-association request frame, the AP multi-link device may send an association response frame or a re-association response frame that does not include the TID-to-link mapping element. In addition, when a non-AP multi-link device sends an association request frame or a re-association request frame including a TID-to-link mapping element, and receives an association response frame or a re-association response frame for setting a link set different from the link set of the multi-link to be set by the association request frame or the re-association request frame, the non-AP multi-link device may determine that the TID-to-link mapping request is rejected even if the received association response frame or the re-association response frame does not include the TID-to-link mapping element. At this time, the AP multi-link device and the non-AP multi-link device may apply a default mapping.

[0454] In another specific embodiment, when the AP multi-link device receives an association request frame or a re-association request frame including a TID-to-link mapping element and wants to set a link set different from the link set of the multi-link to be set by the association request frame or the re-association request frame, the AP multi-link device may send an association response frame or a re-association response frame including a TID-to-link mapping element. At this time, the TID-to-link mapping element included in the association response frame or the re-association response frame may indicate the TID-to-link mapping suggested by the AP multi-link device. At this time, the operation of the non-AP multi-link device may be the same as that of the reference Fig.28 The embodiments described are the same.

[0455] In the above-mentioned embodiments, for the convenience of explanation, the operation of the multi-link device is described, but the operation of the multi-link device may also be performed by the stations included in the multi-link device.

[0456] Fig.34 is a diagram showing an example of the format of a TBTT information field according to an embodiment of the present invention.

[0457] Fig.34 Yes Fig. 27 Supplementary description of the TBTT information fields described in , and Fig. 27 The contents described in also apply to this embodiment, but will be omitted.

[0458] The AP or AP MLD may send a Reduced Neighbor Report (RNR) element, and the non-AP STA or non-AP MLD may receive the RNR element. The RNR element may include information about the AP or AP MLD or the BSS. The non-AP STA or non-AP MLD may probe the AP or AP MLD based on the received RNR element. The non-AP STA or non-AP MLD may further request indication information from the AP or AP MLD based on the received RNR element. For example, the non-AP STA or non-AP MLD may send a probe request frame to the AP or AP MLD based on the received RNR element. Alternatively, the non-AP STA or non-AP MLD may perform (re)association or multi-link (re)setting based on the received RNR element. The (re)association or multi-link (re)setting may be performed by the non-AP STA or non-AP MLD sending a (re)association request frame.

[0459] The RNR element may include one or more neighbor AP information fields.

[0460] The neighbor AP information field may include a TBTT information set field.

[0461] The TBTT information set field may include one or more TBTT information fields. The number of TBTT information fields included in the TBTT information set field may be indicated by the TBTT information count subfield included in the above-mentioned TBTT information set field.

[0462] The length of each TBTT information field included in the TBTT information set field included in the neighbor AP information field can be indicated by the TBTT information length subfield included in the above neighbor AP information field. That is, the length of the TBTT information field included in one neighbor AP information field can be the same.

[0463] The format and content of the TBTT information field can be determined based on the TBTT information header field included in the neighbor AP information field that includes the TBTT information field. More specifically, the format and content of the TBTT information field can be determined based on the TBTT information field type and the TBTT information field length indicated by the neighbor AP information field that includes the TBTT information field. The above-mentioned TBTT information field type can be indicated by a TBTT information field type subfield. In addition, the above-mentioned TBTT information field length can be indicated by a TBTT information length subfield. The neighbor AP information field includes a TBTT information field type subfield and a TBTT information length subfield. Therefore, the format and content of the TBTT information field included in a neighbor AP information field can be the same.

[0464] Specifically, the TBTT information fields included in the neighbor AP information field may all have the same format, and the length and content, etc. may be the same, and the length may be indicated by the TBTT information length subfield. If the length of the TBTT information field is indicated by the TBTT information length subfield, the format and content of the TBTT information field may be determined based on the length. For example, the included content may be different depending on the length of the TBTT information field.

[0465] In addition, the operation of the terminal that processes the TBTT information field may be different based on the value of the TBTT information field type subfield and the value of the TBTT information length subfield included in the TBTT information header field of the neighbor AP information field. Specifically, the length of the TBTT information field processed by the terminal may be different depending on whether the value of the TBTT information field type subfield indicating the type (or format) of the TBTT information field is a first value (e.g., "0") or a second value (e.g., "1"). In addition, the length of the TBTT information field processed may additionally consider the value of the TBTT information length subfield. That is, when the value of the TBTT information field subfield is set to the first value or the second value, the terminal processes all or only part of the TBTT information field by comparing the value of the TBTT information length subfield with the first threshold (e.g., 16 octets), the second threshold (e.g., 13 octets) and / or the third threshold (e.g., 3 octets), or may not process it at all. For example, if the length of the TBTT information field indicated by the TBTT information length subfield is equal to or less than the second threshold value when the recognizable value of the TBTT information field subfield is "0", the terminal may not process and ignore the entire TBTT information field of the received frame (e.g., a beacon frame or a probe response frame, etc.). However, if the length of the TBTT information field indicated by the TBTT information length subfield is greater than the second threshold value and equal to or less than the first threshold value when the recognizable value of the TBTT information field subfield is "0", the terminal may only process up to the first second octet value (e.g., 13 octets) of the TBTT information field of the received frame, and may not process and ignore the remaining octets. However, if the length of the TBTT information field indicated by the TBTT information length subfield is greater than the first threshold value when the recognizable value of the TBTT information field subfield is "0", the terminal may only process up to the first first octet value (e.g., 16 octets) of the TBTT information field of the received frame, and may not process and ignore the remaining octets.

[0466] If the length of the TBTT information field indicated by the TBTT information length subfield is less than the third threshold value when the recognizable value of the TBTT information field subfield is "1", the terminal may not process and ignore all TBTT information fields of the received frame (e.g., beacon frame or probe response frame, etc.). However, if the length of the TBTT information field indicated by the TBTT information length subfield is equal to or greater than the third threshold value when the recognizable value of the TBTT information field subfield is "1", the terminal may only process up to the first third octet value (e.g., 3 octets) of the TBTT information field of the received frame, and may not process and ignore the remaining octets.

[0467] As another embodiment of the present invention, the TBTT information field can be processed up to a specific threshold value according to whether the value of the TBTT information length subfield includes a specific threshold value. That is, if the value of the TBTT information length subfield is less than the specific threshold value, the corresponding TBTT information field may not be processed. However, if the value of the TBTT information length subfield is above the specific threshold value (equal to or greater than the specific threshold value), the TBTT information field may be processed up to the length (eight bits) corresponding to the specific threshold value. At this time, if the value of the TBTT information length field is a value between two thresholds (for example, above the second threshold value and less than the first threshold value), the TBTT information field may be processed up to the length corresponding to the second threshold value.

[0468] For example, when the value of the TBTT information field subfield is set to the first value or the second value, the terminal processes all or only part of the TBTT information field by comparing the value of the TBTT information length subfield with the first threshold (e.g., 16 octets), the second threshold (e.g., 13 octets) and / or the third threshold (e.g., 3 octets), or may not process all of the TBTT information field. Specifically, if the length of the TBTT information field indicated by the TBTT information length subfield is less than the second threshold value when the identifiable value of the TBTT information field subfield is "0", the terminal may not process and ignore the entire TBTT information field of the received frame (e.g., a beacon frame or a probe response frame, etc.). However, if the length of the TBTT information field indicated by the TBTT information length subfield is equal to or greater than the second threshold value and less than the first threshold value when the identifiable value of the TBTT information field subfield is "0", the terminal may only process up to the first second octet value (e.g., 13 octets) of the TBTT information field of the received frame, and may not process and ignore the remaining octets. However, if the length of the TBTT information field indicated by the TBTT information length subfield is equal to or greater than the first threshold when the recognizable value of the TBTT information field subfield is "0", the terminal may only process up to the first eight-bit byte value (for example, 16 eight-bit bytes) of the TBTT information field of the received frame, and may not process and ignore the remaining eight-bit bytes.

[0469] If the length of the TBTT information field indicated by the TBTT information length subfield is less than the third threshold value when the recognizable value of the TBTT information field subfield is "1", the terminal may not process and ignore all TBTT information fields of the received frame (e.g., beacon frame or probe response frame, etc.). However, if the length of the TBTT information field indicated by the TBTT information length subfield is equal to or greater than the third threshold value when the recognizable value of the TBTT information field subfield is "1", the terminal may only process up to the first third octet value (e.g., 3 octets) of the TBTT information field of the received frame, and may not process and ignore the remaining octets.

[0470] The TBTT information field type subfield may have a value of 0 to 3. In addition, the EHT STA may understand, recognize, and identify the case where the TBTT information field type subfield value is 0 or 1. In addition, the EHT STA may not recognize the case where the TBTT information field type subfield value is 2 or 3. A HE STA or a STA of a previous standard that is different from the EHT STA may understand, recognize, and identify the case where the TBTT information field type subfield value is 0, but may not recognize the case where the TBTT information field type subfield value is 1 to 3.

[0471] Fig. 27 The TBTT information field configuration described in can be an embodiment in which the TBTT information field type subfield value is 0. Fig.34 (a) shows Fig.21 According to one embodiment, when the TBTT information field type subfield value is 0 and the TBTT information length subfield value is 1, 2, 5, 6, 7, 8, 9, 11, 12, 13, 16 or 17 or greater, the corresponding TBTT information field content (the subfields included in the TBTT information field) can be the same as Fig. 27 In addition, when the TBTT information field type subfield value is 0 and the TBTT information length subfield value is 0, 3, 4, 10, 14, or 15, the corresponding TBTT information field may be undefined (reserved). In addition, when the TBTT information field type subfield value is 0, the corresponding TBTT information field may always include the neighbor AP TBTT offset subfield.

[0472] Fig.34(b) shows the TBTT information field format when the TBTT information field type subfield value is 1. If the TBTT information field type subfield value is 1, the corresponding TBTT information field may include the MLD parameter field. For example, if the TBTT information field type subfield value is 1, the corresponding TBTT information field may always include the MLD parameter field. In addition, when the TBTT information field type subfield value is 1 and the TBTT information length subfield value is 3, the corresponding TBTT information field may include the MLD parameter field.

[0473] In the present invention, the TBTT information field corresponding to the TBTT information field type subfield or the TBTT information length subfield may represent the TBTT information field included in the neighbor AP information field including the TBTT information field type subfield or the TBTT information length subfield.

[0474] The MLD parameter field may include Fig. 27 The All Updates Included subfield may include the subfield described in the BSS parameter change count subfield, and may additionally include the All Updates Included subfield in the bit at position B20. The All Updates Included subfield may indicate whether the frame in which the RNR element including the All Updates Included subfield is located includes all update elements that change the value of the BSS parameter change count subfield. If all are included, it may be set to 1, otherwise, it may be set to 0.

[0475] According to an embodiment of the present invention, the plurality of STAs may include a STA (ie, AP) attached to an AP MLD. For example, there may be a case where the AP MLD operates on an NSTR link pair. The AP MLD may be referred to as an NSTR AP MLD, an NSTR mobile AP MLD, or an NSTR soft AP MLD.

[0476] The NSTR mobile AP MLD can set, allocate and specify the main link and the non-main link. In addition, the non-AP MLD that has performed multi-link setting with the NSTR mobile AP MLD can receive information about which link is the main link and which link is the non-main link from the NSTR mobile AP MLD and make a judgment. The NSTR mobile AP MLD may only send beacon frames, probe response frames, association response frames and re-association response frames on the main link. The NSTR mobile AP MLD may not be able to send beacon frames, probe response frames, association response frames and re-association response frames on the non-main link. In addition, the non-AP MLD that has set up (or wants to set up) multi-links with the NSTR mobile AP MLD may only send probe request frames, association request frames and re-association request frames on the main link. The non-AP MLD associated with the NSTR mobile AP MLD or set up (or wants to set up) multi-links with the NSTR mobile AP MLD may not be able to send probe request frames, association request frames or re-association request frames on the non-main link.

[0477] In addition, the NSTR mobile AP MLD or the non-AP MLD associated with the NSTR mobile AP MLD may need to use the main link together to start TXOP (start frame transmission) on the non-main link. For example, in order to start PPDU transmission on the non-main link, PPDU transmission may need to be started simultaneously on the main link and on the non-main link. In addition, there may be a backoff process to start PPDU transmission on the main link and the non-main link at the same time. For example, on the link where the backoff counter reaches 0, the backoff counter value 0 may be maintained, and on the link where the backoff counter is 0, when the backoff counter on another link reaches 0, PPDU transmission may be started.

[0478] In addition, the AP MLD can indicate whether it is an NSTR mobile AP MLD or an AP MLD (AP MLD operating on an STR link pair) instead of an NSTR mobile AP MLD. For example, Fig. 20 The multilink element described in the description may include the above indication. More specifically, the MLD capability field of the common information field included in the multilink element may include the above indication. More specifically, bit B7 of the MLD capability field may represent the above indication. The above indication may exist when the AP MLD sends a multilink element. For example, when the NSTR mobile AP MLD sends a multilink element, the above bit value may be set to 1. If an AP MLD other than the NSTR mobile AP MLD sends a multilink element, the above bit value may be set to 0. The non-AP MLD that receives the above bit may determine whether the multilink element including the above bit is an NSTR mobile AP MLD based on the above bit.

[0479] In addition, when sending the RNR element, the NSTR mobile AP MLD may include only the MLD parameter subfield in the TBTT information field corresponding to the NSTR mobile AP MLD. In addition, there may not be a situation where an AP MLD other than the NSTR mobile AP MLD includes only the MLD parameter subfield in the TBTT information field corresponding to the above AP MLD when sending the RNR element. The RNR element may be included in a beacon frame, a probe response frame, an association response frame, and a reassociation response frame. Therefore, a non-AP MLD receiving the TBTT information field may determine whether the AP MLD corresponding to the above TBTT information field is an NSTR mobile AP MLD based on whether the TBTT information field includes only the MLD parameter field. Whether the TBTT information field includes only the MLD parameter subfield may be determined based on a field indicating the length or type of the TBTT information field. For example, the MLD parameter subfield may have a preset length, such as 3 octets. In addition, when the value indicating the length of the TBTT information field indicates a preset length, it may be determined that the above TBTT information field includes only the MLD parameter subfield and the above TBTT information field corresponds to the NSTR mobile AP MLD.

[0480] Alternatively, the AP or AP MLD (e.g., NSTR mobile AP MLD) may set the neighbor AP information field of the corresponding link differently to indicate which link is the primary link or the non-primary link. For example, when the TBTT information field type subfield is set to a preset value, the neighbor AP information field including the above-mentioned TBTT information field type subfield or the TBTT information field corresponding to the above-mentioned TBTT information field type subfield may indicate whether the corresponding AP is operating on the primary link or the non-primary link. More specifically, when the TBTT information field type subfield is set to a preset value, the neighbor AP information field including the above-mentioned TBTT information field type subfield or the TBTT information field corresponding to the above-mentioned TBTT information field type subfield may indicate that the corresponding AP is operating on the non-primary link. The above-mentioned preset value may be 1.

[0481] Alternatively, when the TBTT information field includes the MLD parameter field but does not include all of the neighbor AP TBTT offset subfield, the BSSID subfield, the short SSID subfield, the BSS parameter subfield, and the 20MHz PSD subfield, it can indicate whether the AP corresponding to the above TBTT information field is operating on the primary link or on a non-primary link. More specifically, when the TBTT information field includes the MLD parameter field but does not include all of the neighbor AP TBTT offset subfield, the BSSID subfield, the short SSID subfield, the BSS parameter subfield, and the 20MHz PSD subfield, it can indicate that the AP corresponding to the above TBTT information field is operating on a non-primary link.

[0482] Therefore, among the APs affiliated to the NSTR mobile AP MLD, the AP operating on the primary link can send a neighbor AP information field or a TBTT information field corresponding to a non-primary link or an AP operating on a non-primary link. At this time, the TBTT information field type subfield value included in the neighbor AP information field can be set to 1. In addition, the above-mentioned TBTT information field may include the MLD parameter field, and may not include all of the neighbor AP TBTT offset subfield, the BSSID subfield, the short SSID subfield, the BSS parameter subfield, and the 20MHz PSD subfield.

[0483] In addition, among the APs affiliated to the NSTR mobile AP MLD, the AP operating on the main link can send a neighbor AP information field or a TBTT information field corresponding to the main link or the above-mentioned AP. At this time, the TBTT information field type subfield value included in the neighbor AP information field can be set to 0. In addition, the TBTT information field can include an MLD parameter field.

[0484] A STA or non-AP MLD that receives the neighbor AP information field or TBTT information field set according to the above embodiment can determine whether the received neighbor AP information field or the received TBTT information field corresponds to the NSTR mobile AP MLD, or corresponds to the AP operating on the main link, or corresponds to the AP operating on the non-main link.

[0485] Fig.35 is a diagram of operations of receiving and parsing a neighbor AP information field according to an embodiment of the present invention.

[0486] According to an embodiment of the present invention, when a STA receives a neighbor AP information field including an unrecognized (unrecognizable, unknown) TBTT information field type subfield value, the neighbor AP information field or the remaining part of the RNR element including the neighbor AP information field can be ignored.

[0487] According to an embodiment of the present invention, an AP (reporting AP) included in an AP MLD may send a frame (e.g., a beacon frame or a probe response frame) including a reduced neighbor report (RNR) element to a STA included in a non-AP MLD. The non-AP STA may obtain information of other APs (reported APs) included in the AP MLD based on the received RNR element. At this time, the content and format of the TBTT information related to the information of other APs may be identified based on the TBTT information field type subfield and the TBTT information length subfield included in the RNR element of the frame. In addition, depending on the value of the TBTT information field type subfield, the non-AP STA may be able to process the length of the TBTT information field based on the TBTT information length field, which may be different. In this case, the content (or information) of the unprocessed TBTT information field may be ignored.

[0488] The TBTT information field type subfield and the TBTT information length subfield may be included in a TBTT information header included in the neighbor AP information field of the RNR element.

[0489] The TBTT information length subfield may indicate the length (e.g., octets) of each TBTT information field included in the TBTT information set, and its value may be 1, 5, 7, or 11. However, this is just an example, and the TBTT information length subfield may have a value other than 1, 5, 7, or 11. In addition, the TBTT information length subfield may indicate the content of the TBTT information field.

[0490] There may be a method of operation when a STA receives a neighbor AP information field including an identified (identifiable, knowable) TBTT information field type subfield value and an unidentified TBTT information length subfield value. For example, as described above, there may be a method based on threshold 1 and threshold 2.

[0491] For example, when the TBTT information length subfield is less than or equal to threshold 1, the neighbor AP information field including the TBTT information length subfield may be ignored, and the subsequent neighbor AP information field may be processed (decoded). (Operation 1)

[0492] When the TBTT information length subfield is greater than threshold 1, the first octet of threshold 1 of each corresponding TBTT information field can be processed as if the TBTT information length subfield value is threshold 1, the remaining octets of each corresponding TBTT information field ((TBTT information length subfield value - threshold 1) octets) are ignored, and the subsequent neighbor AP information field is processed. In addition, this can be an embodiment with threshold 1 being less than threshold 2 and the TBTT information length subfield being less than threshold 2 as additional conditions. (Operation 2)

[0493] When the TBTT information length subfield is greater than threshold 2, the first threshold 2 octet of each corresponding TBTT information field may be processed as if the TBTT information length subfield value is threshold 2, the remaining octets of each corresponding TBTT information field ((TBTT information length subfield value - threshold 2) octets) are ignored, and subsequent neighbor AP information fields are processed. (Operation 3)

[0494] According to an embodiment, threshold 1 may be 13. In addition, threshold 2 may be 16.

[0495] As an additional embodiment, there may be a threshold value 3 that is greater than threshold value 2. In the aforementioned embodiment regarding threshold value 1 and threshold value 2, there may be an embodiment in which threshold value 1 and threshold value 2 are changed to threshold value 2 and threshold value 3, respectively.

[0496] That is, as available operation methods, there may be operation 1, operation 2, and operation 3. STA may perform operation 1 according to the condition described for operation 1. In addition, HE STA may perform operation 2 according to the condition described for operation 2. Non-HE STA may perform operation 1 or operation 2 according to the condition described for operation 2. EHT STA may perform operation 3 according to the condition described for operation 3. Non-EHT STA may perform operation 1, operation 2, or operation 3 according to the condition described for operation 3.

[0497] In the described embodiment, processing the portion of the TBTT information field with the unknown TBTT information length subfield value equivalent to the threshold and ignoring the rest may be for forward compatibility. This may be to enable parsing as much as possible when it is defined that the TBTT information field includes information different from the information included in the TBTT information field known to the STA.

[0498] Reference Fig.35, the STA may receive a neighbor AP information field including an identified TBTT information field type subfield value and an unidentified TBTT information length subfield value. In this case, it may be confirmed whether the TBTT information length subfield value is less than or equal to 13. If it is "yes", the neighbor AP information field may be ignored. If it is "no", it may be confirmed whether the TBTT information length subfield value is greater than 16. If it is "no" (the case where the TBTT information length subfield value is greater than 13 and less than 16), the first 13 octets of each TBTT information field included in the neighbor AP information field may be processed as if the TBTT information length subfield value is 13, and the remaining TBTT information fields except the first 13 octets may be ignored. If it is "yes" (the case where the TBTT information length subfield value is greater than 16), the first 16 octets of each TBTT information field included in the neighbor AP information field may be processed as if the TBTT information length subfield value is 16, and the remaining TBTT information fields except the first 16 octets may be ignored.

[0499] However, considering the forward compatibility of the design of the TBTT information field, it may be in the direction of increasing the length of the TBTT information field, but this may correspond to a TBTT information field type subfield value. That is, for other TBTT information field type subfield values, it may not be defined in the direction of increasing the length of the TBTT information field. Therefore, when an unrecognized TBTT information length subfield value is received, it will cause problems in parsing the neighbor AP information field.

[0500] For example, Fig.35 As shown in Example 1, a neighbor AP information field with a TBTT information length subfield value greater than 3 and less than or equal to 13 may be received. In addition, the TBTT information field type subfield value included in the neighbor AP information field may be 1. In this case, the TBTT information field actually sent may be the same as Fig.35 The same as shown in Example 1. That is, the MLD parameter field that may include 3 octets may be included in the front, and the new field 1 may be followed. In addition, for example, the length of the new field 1 may be 3 octets. The EHT STA is able to recognize that the TBTT information field type subfield value is 1, but cannot recognize that the TBTT information length subfield value is greater than 3, so it can operate according to the embodiment described in 35. Therefore, since the value of the TBTT information length subfield is less than or equal to 13, the neighbor AP information field can be ignored. Therefore, the STA cannot obtain information from the resolvable MLD parameter field.

[0501] like Fig.35As shown in Example 2, a neighbor AP information field with a TBTT information length subfield value greater than 16 may be received. In addition, the TBTT information field type subfield value included in the neighbor AP information field may be 1. In this case, the TBTT information field actually sent may be the same as Fig.35 The same as shown in Example 2. That is, the MLD parameter field of 3 octets may be included in the front, followed by the new field 2. In addition, for example, the length of the new field 2 may be 14 octets. The EHT STA may recognize that the TBTT information field type subfield value is 1, but cannot recognize that the TBTT information length subfield value is greater than 3, so it may be based on Fig.35 Therefore, since the TBTT information length subfield value is greater than 16, the first 16 octets of the TBTT information field included in the neighbor AP information field can be parsed as if the TBTT information length subfield value is 16. However, since the TBTT information field when the TBTT information length subfield value is 16 is different from Fig.35 The interpretation of STA in (Example 2) is the same as shown, so in practice the information consisting of the MLD parameter and the new field 2 (Example 2) is incorrectly parsed as the interpretation of STA.

[0502] Fig.36 is a diagram of operations of receiving and parsing a neighbor AP information field according to an embodiment of the present invention.

[0503] Fig.36 An embodiment may be used to solve Fig.35 In addition, the aforementioned contents may have been omitted in the present embodiment. In addition, the terms "above" (greater than or equal to), "below" (less than or equal to), "exceed" (greater than), "less than" (less than) and the like in the present invention or embodiments having the same meanings may be extended to embodiments in which the embodiments of "exceed" (greater than), "less than" (less than), "above" (greater than or equal to), "below" (less than or equal to) are replaced respectively.

[0504] According to an embodiment of the present invention, when a STA receives a neighbor AP information field including an unrecognized (unrecognizable, unknown) TBTT information field type subfield value, the neighbor AP information field or the rest of the RNR element including the neighbor AP information field can be ignored.

[0505] That is, the AP (reporting AP) included in the AP MLD may send a frame (e.g., a beacon frame or a probe response frame, etc.) including an RNR element to the non-AP STA included in the non-AP MLD, and the non-AP STA may acquire and discover information about other APs (reported APs) included in the AP MLD based on this. At this time, when the value of the TBTT information field type subfield included in the RNR element is an unrecognizable (or unknown) value, the non-AP STA may not process and ignore the remaining fields (or octets) of the RNR element. However, when the value of the TBTT information field type subfield included in the RNR element is a recognizable (or knowable) value, the non-AP STA may process only a partial length (or partial octets) of the TBTT information field included in the TBTT information set or process all of it based on the value of the TBTT information field type subfield and according to the value of the TBTT information length subfield. At this time, the unprocessed portion may be ignored.

[0506] Specifically, the TBTT information fields included in the neighbor AP information field may all have the same format, and the length and content, etc. may be the same, and the length may be indicated by the TBTT information length subfield. If the length of the TBTT information field is indicated by the TBTT information length subfield, the format and content of the TBTT information field may be determined based on the length. For example, the included content may be differen...

Claims

1. A multi-link device (MLD) comprising a plurality of stations each operating in a plurality of links, wherein: processor: receiving a frame from an access point (AP) of an AP MLD including a plurality of APs, wherein the frame includes a Reduced Neighbor Report (RNR) element, the RNR element includes one or more neighbor AP information fields, the neighbor AP information fields include information related to other APs included in the AP MLD, and The neighbor AP information field includes a target beacon transmission time (TBTT) information setting field, and the TBTT information setting field includes a TBTT information field type subfield, a TBTT information length field, and one or more TBTT information fields. performing processing on each of the one or more TBTT information fields based on the TBTT information type subfield and the TBTT information length field, wherein, when the value of the TBTT information type subfield is "0", by comparing the value of the TBTT information length field with the first threshold value and / or the second threshold value, each of the one or more TBTT information fields is processed only up to the first octet value or the second octet value, and When the value of the TBTT information type subfield is "1", each of the one or more TBTT information fields is processed only up to the third octet value by comparing the value of the TBTT information length field with the third threshold.

2. The MLD according to claim 1, wherein: The TBTT information field type subfield is used to indicate the content and / or length of the one or more TBTT information fields, and The TBTT information length field indicates the length of each of the one or more TBTT information fields.

3. The MLD according to claim 1, wherein: When the value of the TBTT information type subfield is "0" and the value of the TBTT information length field is less than the first threshold and equal to or greater than the second threshold, each of the one or more TBTT information fields is processed only up to the second octet value, and The second octet value is less than the first octet value.

4. The MLD according to claim 3, wherein: In each of the one or more TBTT information fields, the remaining octets except the value up to the second octet value are not processed.

5. The MLD according to claim 1, wherein: When the value of the TBTT information type subfield is "0" and the value of the TBTT information length field is equal to or greater than the first threshold, the one or more TBTT information fields are processed only up to the first octet value, and The second octet value is less than the first octet value.

6. The MLD according to claim 5, wherein: In each of the one or more TBTT information fields, the remaining octets except the value up to the first octet value are not processed.

7. The MLD according to claim 1, wherein: When the value of the TBTT information type subfield is "0" and the value of the TBTT information length field is less than the second threshold, the one or more TBTT information fields are not processed.

8. The MLD according to claim 1, wherein: When the value of the TBTT information type subfield is "1" and the value of the TBTT information length field is greater than or equal to the third threshold, the one or more TBTT information fields are only processed up to the third octet value.

9. The MLD according to claim 8, wherein: In each of the one or more TBTT information fields, the remaining octets except for the value up to the third octet value are not processed.

10. The MLD according to claim 1, wherein: When the value of the TBTT information type subfield is "1" and the value of the TBTT information length field is less than the third threshold, the one or more TBTT information fields are not processed.

11. The MLD according to claim 1, wherein: Each of the one or more TBTT information fields includes a Neighbor AP TBTT Offset subfield, and The neighbor AP TBTT offset subfield indicates the offset between the TBTT used by the AP to send beacon frames and the TBTT used by another AP to send beacon frames.

12. The MLD according to claim 11, wherein: When the other AP is included in the AP MLD, the offset value indicated by the neighbor AP TBTT offset subfield is set to a value other than a preset value associated with "unknown".

13. The MLD according to claim 12, wherein: The preset value is "255".

14. A method performed by a multi-link device (MLD) in a wireless communication system, the MLD comprising a plurality of stations operating on a plurality of links respectively, the method comprising the following steps: receiving a frame from an access point (AP) of an AP MLD including a plurality of APs, wherein the frame includes a Reduced Neighbor Report (RNR) element, the RNR element includes one or more neighbor AP information fields, the neighbor AP information fields include information related to other APs included in the AP MLD, and The neighbor AP information field includes a target beacon transmission time (TBTT) information setting field, and the TBTT information setting field includes a TBTT information field type subfield, a TBTT information length field, and one or more TBTT information fields; and processing each of the one or more TBTT information fields based on the TBTT information type subfield and the TBTT information length field, wherein, when the value of the TBTT information type subfield is "0", by comparing the value of the TBTT information length field with the first threshold value and / or the second threshold value, each of the one or more TBTT information fields is processed only up to the first octet value or the second octet value, and Wherein, when the value of the TBTT information type subfield is "1", by comparing the value of the TBTT information length field with the third threshold, each of the one or more TBTT information fields is only processed to the third octet value.

15. The method according to claim 14, wherein: The TBTT information field type subfield is used to indicate the content and / or length of the one or more TBTT information fields, and The TBTT information length field indicates the length of each of the one or more TBTT information fields.

16. The method according to claim 14, wherein: When the value of the TBTT information type subfield is "0" and the value of the TBTT information length field is less than the first threshold and equal to or greater than the second threshold, each of the one or more TBTT information fields is processed only up to the second octet value, and The second octet value is less than the first octet value.

17. The method according to claim 16, wherein: In each of the one or more TBTT information fields, the remaining octets except the value up to the second octet value are not processed.

18. The method according to claim 14, wherein: When the value of the TBTT information type subfield is "0" and the value of the TBTT information length field is equal to or greater than the first threshold, the one or more TBTT information fields are processed only up to the first octet value, and The second octet value is less than the first octet value.

19. The method according to claim 18, wherein: In each of the one or more TBTT information fields, the remaining octets except the value up to the first octet value are not processed.

20. The method according to claim 14, wherein: When the value of the TBTT information type subfield is "0" and the value of the TBTT information length field is less than the second threshold, the one or more TBTT information fields are not processed.

21. The method according to claim 14, wherein: When the value of the TBTT information type subfield is "1" and the value of the TBTT information length field is greater than or equal to the third threshold, the one or more TBTT information fields are only processed up to the third octet value.

22. The method according to claim 21, wherein: In each of the one or more TBTT information fields, the remaining octets except for the value up to the third octet value are not processed.

23. The method according to claim 14, wherein: When the value of the TBTT information type subfield is "1" and the value of the TBTT information length field is less than the third threshold, the one or more TBTT information fields are not processed.

24. The method according to claim 14, wherein: Each of the one or more TBTT information fields includes a Neighbor AP TBTT Offset subfield, and The neighbor AP TBTT offset subfield indicates the offset between the TBTT used by the AP to send beacon frames and the TBTT used by another AP to send beacon frames.

25. The method according to claim 24, wherein: When the other AP is included in the AP MLD, the offset value indicated by the neighbor AP TBTT offset subfield is set to a value other than a preset value associated with "unknown".

26. The method according to claim 25, wherein: The preset value is "255".

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