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

Abstract

A multi-link device using multiple links is disclosed. The multi-link device includes a transceiving unit; and a processor. When the multi-link device simultaneously transmits multiple PPDUs on multiple links using the transceiving unit, the processor determines an end time of transmission of the multiple PPDUs based on whether the multi-link device transmits a frame requesting an ACK.

Description

TECHNICAL FIELD

[0001] The present application relates to a wireless communication method using multiple links and a wireless communication terminal using the same. BACKGROUND

[0002] In recent years, as the supply of mobile devices expands, wireless LAN technology capable of providing fast wireless Internet services to mobile devices has been highlighted. Wireless LAN technology allows mobile devices including smart phones, smart pads, laptop computers, portable multimedia players, embedded devices, and the like to wirelessly access the Internet in a home or a company or a specific service providing area based on a short distance wireless communication technology.

[0003] Since the initial wireless LAN technology using a 2.4 GHz frequency band, the Institute of Electrical and Electronics Engineers (IEEE) 802.11 has commercialized or developed various technology standards. First, IEEE 802.11b supports a communication speed of a maximum of 11 Mbps when using a 2.4 GHz frequency band. In comparison with the 2.4 GHz frequency band, which is significantly congested, IEEE 802.11a, which was commercialized after IEEE 802.11b, uses a 5 GHz frequency band, not a 2.4 GHz frequency band, to reduce the influence of interference, and by using OFDM technology, increases a communication speed to a maximum of 54 Mbps. However, IEEE 802.11a has a disadvantage in that a communication distance is shorter than IEEE 802.11b. In addition, similar to IEEE 802.11b, IEEE 802.11g uses a 2.4 GHz frequency band to achieve a communication speed of a maximum of 54 Mbps and satisfies backward compatibility to significantly attract attention, and further, is superior to IEEE 802.11a in terms of a communication distance.

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

[0005] With the supply of activated wireless LANs, and further, with the diversification of applications using wireless LANs, a demand for a new wireless LAN system supporting a higher throughput (very high throughput (VHT)) than a data processing speed supported by IEEE 802.11n has been focused on. Among them, IEEE 802.11ac supports a wide bandwidth (80 to 160 MHz) in a 5 GHz frequency. The IEEE 802.11ac standard is defined only in the 5 GHz band, but the initial 11ac chipset even supports operation in the 2.4 GHz band for backward compatibility with existing 2.4 GHz band products. In theory, according to this standard, a wireless LAN speed enabling multiple stations can reach a minimum of 1 Gbps, and a maximum single link speed can reach a minimum of 500 Mbps. This is achieved by expanding the concept of a wireless interface accepted 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 256 QAM). In addition, as a scheme for transmitting data by using a 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 speed of a maximum of 7 Gbps by using a beamforming technique, and is suitable for high-bit-rate moving image streaming, such as large-scale data or uncompressed HD video. However, since the 60 GHz band is difficult to penetrate obstacles, it has a disadvantage in that the 60 GHz band can be used only among devices in a near-distance space.

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

[0007] In order to support new multimedia applications such as high-definition video and real-time games, a new wireless LAN standard has been developed to increase the maximum transmission rate. In IEEE 802.11be (extremely high throughput, EHT) as the 7th generation wireless LAN standard, development of the standard is underway with the aim of supporting a transmission rate of up to 30 Gbps in the 2.4 / 5 / 6 GHz band through a wider bandwidth, increased spatial streams, multi-AP cooperation, etc. SUMMARY

[0008] TECHNICAL PROBLEM

[0009] Embodiments of the present invention are directed to a wireless communication method using multiple links and a wireless communication terminal using the same.

[0010] Technical Solution

[0011] A multi-link device using multiple links according to an embodiment of the present disclosure can include a transceiver; and a processor. When the multi-link device simultaneously transmits a plurality of PPDU in a plurality of links using the transceiver, the processor is configured to determine an end time of transmission of the plurality of PPDU based on whether a frame requesting an ACK is transmitted by the multi-link device.

[0012] When the multi-link device simultaneously transmits a plurality of PPDU in a plurality of links, the processor is configured to align ends of a plurality of PPDU among the plurality of PPDU requesting an ACK.

[0013] When the multi-link device simultaneously transmits a plurality of PPDU in a plurality of links, the processor is configured not to align an end of a PPDU including only a frame not requesting an ACK among the plurality of PPDU with an end of a PPDU including a frame requesting an ACK among the plurality of PPDU.

[0014] Specifically, when the multi-link device simultaneously transmits a plurality of PPDU in a plurality of links, the processor is configured to transmit the plurality of PPDU in such a manner that an end of a PPDU including only a frame not requesting an ACK among the plurality of PPDU is not later than an end of a PPDU including a frame requesting an ACK among the plurality of PPDU.

[0015] Whether a frame requesting an ACK is a frame requesting an ACK can be determined based on an ACK policy.

[0016] The frame requesting an ACK is a data frame.

[0017] The multi-link device is an AP multi-link device, and the processor is configured to transmit the plurality of PPDU to a non-AP multi-link device using the transceiver.

[0018] In a case where the multi-link device receiving the plurality of PPDU performs transmission in any one link, the multi-link device cannot perform reception in another link.

[0019] A multi-link device using multiple links according to an embodiment of the present disclosure can include a transceiver; and a processor. The processor is configured to enable the multi-link device to simultaneously receive a plurality of PPDU from a plurality of links using the transceiver. An end time of transmission of the plurality of PPDU can be determined based on whether a frame requesting an ACK is transmitted in the plurality of PPDU.

[0020] An end of a plurality of PPDU among the plurality of PPDU requesting an ACK is aligned.

[0021] The end of the PPDU including only the frame not requesting ACK among the plurality of PPDUs can not be aligned with the end of the PPDU including the frame requesting ACK among the plurality of PPDUs.

[0022] The end of the PPDU including only the frame not requesting ACK among the plurality of PPDUs can not be later than the end of the PPDU including the frame requesting ACK among the plurality of PPDUs.

[0023] Whether the frame requesting ACK is the frame requesting ACK can be determined based on an ACK policy.

[0024] The frame requesting ACK can be a data frame.

[0025] The multi-link device is a non-AP multi-link device, and the processor is configured to transmit, using the receiver, a plurality of PPDUs from an AP multi-link device.

[0026] In a case where the multi-link device performs transmission in any one of the links, the multi-link device cannot perform reception in the other link.

[0027] The processor is configured to access a channel using a channel access method in the plurality of links, the channel access method using a backoff counter. In this instance, an initial value of the backoff counter is set by an obtained random number, the backoff counter is decremented by 1 when the channel accessed during a slot time is idle, and when the value of the backoff counter is 0, the station is allowed to access the channel. Even when the backoff counter reaches 0 in channel access of any one of the plurality of links, the processor can not perform transmission in any one of the links.

[0028] When transmission is not performed in any one of the links, the processor can maintain the value of the backoff counter.

[0029] A method of operating a multi-link device using a plurality of links according to an embodiment of the disclosure can include receiving, by the multi-link device, a plurality of PPDUs simultaneously from the plurality of links using a transceiver. A transmission end time of the plurality of PPDUs can be determined based on whether a frame requesting ACK is transmitted in the plurality of PPDUs.

[0030] The end of the plurality of PPDUs requesting ACK among the plurality of PPDUs can be aligned.

[0031] Advantageous Effects

[0032] Embodiments of the disclosure provide a wireless communication method effectively using a multi-link and a wireless communication terminal using the same. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 A wireless LAN system according to an embodiment of the disclosure is illustrated.

[0034] Figure 2 A wireless LAN system according to another embodiment of the present application is illustrated.

[0035] Figure 3 A configuration of a station according to an embodiment of the present application is illustrated.

[0036] Figure 4 A configuration of an access point according to an embodiment of the present application is illustrated.

[0037] Figure 5 A procedure in which a STA and an AP set up a link is schematically illustrated.

[0038] Figure 6 A carrier sense multiple access (CSMA) / collision avoidance (CA) method used in wireless LAN communication is illustrated.

[0039] Figure 7 Examples of formats of PLCP protocol data units (PPDUs) for each of various standards generations are illustrated.

[0040] Figure 8 Examples of various extremely high throughput (EHT) physical protocol data unit (PPDU) formats according to embodiments of the present application and methods for indicating the formats are illustrated.

[0041] Figure 9 A multi-link device according to embodiments of the present disclosure is illustrated.

[0042] Figure 10 is a diagram illustrating a case in which transmissions in different links are simultaneously performed in multi-link operation according to embodiments of the present disclosure.

[0043] Figure 11 is a diagram illustrating operation in which a multi-link device simultaneously terminates transmissions in multiple links according to embodiments of the present disclosure.

[0044] Figure 12 is a diagram illustrating operation in which a multi-link device first terminates a transmission in any one link by the multi-link device when the multi-link device performs transmissions in multiple links according to embodiments of the present disclosure.

[0045] Figure 13 is a diagram illustrating operation in which a multi-link device defers a transmission in another link by the multi-link device when the multi-link device performs a transmission in any one link according to embodiments of the present disclosure.

[0046] Figure 14 is a diagram illustrating operation in which a multi-link device first terminates a transmission in any one link by the multi-link device when the multi-link device performs transmissions in multiple links according to embodiments of the present disclosure.

[0047] Figure 15 is a diagram illustrating an operation by which a multi-link device first terminates transmission in any one link in a case where the multi-link device performs transmission in multiple links according to another embodiment of the disclosure.

[0048] Figure 16 is a diagram illustrating an operation by which a multi-link device operates using mapping between a link and a TID according to an embodiment of the disclosure.

[0049] Figure 17 is a diagram illustrating an operation by which a station performs UL MU transmission according to an embodiment of the disclosure.

[0050] Figure 18 is a diagram illustrating an operation by which a multi-link device performs multi-TID aggregation according to an embodiment of the disclosure.

[0051] Figure 19 is a diagram illustrating an element by which information associated with mapping between a link and a TID is signaled according to an embodiment of the disclosure.

[0052] Figure 20 is a diagram illustrating an operation by which a station performs channel access in order to transmit a trigger frame according to an embodiment of the disclosure.

[0053] Figure 21 is a diagram illustrating an operation by which a multi-link device performs transmission in multiple links according to an embodiment of the disclosure.

[0054] Figure 22 is a diagram illustrating an operation by which a multi-link device sets a NAV according to an embodiment of the disclosure.

[0055] Figure 23 is a diagram illustrating an operation by which a multi-link device sets a NAV according to an embodiment of the disclosure.

[0056] Figure 24 is a diagram illustrating an operation by which a station of a multi-link device suspends performing channel access or transmission and resumes performing channel access or transmission due to reception of a PPDU by another station of the multi-link device according to an embodiment of the disclosure.

[0057] Figure 25 is a diagram illustrating a method by which a multi-link device transmits a response to a trigger frame in a case where a NAV is set for the multi-link device and the trigger frame is received according to an embodiment of the disclosure. DETAILED DESCRIPTION

[0058] By considering the functions of the present application, the terms used in the present specification adopt common general terms which are widely used at present, but the terms can be changed according to the intention of those skilled in the art, customs, and appearance of new technologies. Also, in a specific case, there are terms arbitrarily selected by the applicant, and in this case, the meanings thereof will be described in the corresponding description part of the present application. Therefore, it should be understood that the terms used in the present specification should be analyzed based on not only the names of the terms but also the substantial meanings of the terms and the contents of the whole specification.

[0059] Throughout the specification and the subsequent claims, when describing that one element is "coupled" to another element, the one element can be "directly coupled" to the other element, or "electrically coupled" to the other element via a third element. Also, unless explicitly described to the contrary, the word "comprise" will be understood to imply the inclusion of stated elements but not the exclusion of any other elements. Also, a limitation such as "or more" or "or less" based on a specific threshold can be replaced with "greater than" or "less than" respectively, as appropriate.

[0060] Hereinafter, in the present application, a field and a subfield can be used interchangeably.

[0061] Figure 1 FIG. 1 is a diagram illustrating a wireless LAN system according to an embodiment of the present application.

[0062] Figure 1 is a diagram illustrating a wireless LAN system according to an embodiment of the present application. The wireless LAN system includes one or more basic service sets (BSSs), and the BSSs represent a set of devices which successfully synchronize with each other to communicate with each other. Generally, the BSSs can be divided into an infrastructure BSS and an independent BSS (IBSS), and Figure 1 FIG. 1 illustrates infrastructure BSSs between them.

[0063] As Figure 1 illustrated, the infrastructure BSSs (BSS1 and BSS2) include one or more stations STA1, STA2, STA3, STA4, and STA5, access points AP-1 and AP-2 which are stations providing a distributed service, and a distribution system (DS) connecting the plurality of access points AP-1 and AP-2.

[0064] A station (STA) is a predetermined device including a medium access control (MAC) complying with the provisions of the IEEE 802.11 standard and a physical layer interface for a wireless medium, and broadly includes both a non-access point (non-AP) station and an access point (AP). Also, in the present specification, the term "terminal" can 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 according to an embodiment, can further include a user interface unit and a display unit. The processor can generate a frame to be transmitted via a wireless network, or process a frame received via a wireless network, and in addition, perform various processes for controlling the station. Also, the communication unit is functionally connected with the processor, and transmits and receives frames via a wireless network for the station. According to the present application, a terminal can be used as a term including a user equipment (UE).

[0065] An access point (AP) is an entity that provides access to a distribution system (DS) via a wireless medium for stations associated with it. In an infrastructure BSS, communication among non-AP stations is in principle performed via the AP, but even allows direct communication among non-AP stations when a direct link is configured. Meanwhile, in the present application, the AP is used as a concept including a personal BSS coordinator point (PCP), and can broadly include concepts including a central controller, a base station (BS), a node B, a base transceiver system (BTS), and a site controller. In the present application, the AP can also be referred to as a base station wireless communication terminal. The base station wireless communication terminal can be used as a term broadly including an AP, a base station, an eNB (i.e., an eNode B), and a transmission point (TP). Also, the base station wireless communication terminal can include various types of wireless communication terminals that allocate medium resources and perform scheduling of communication with a plurality of wireless communication terminals.

[0066] A plurality of infrastructure BSSs can be connected to each other via a distribution system (DS). In this case, a plurality of BSSs connected via a distribution system is referred to as an extended service set (ESS).

[0067] Figure 2 FIG. 1 illustrates an independent BSS according to another embodiment of the present application, which is a wireless LAN system. In Figure 2 the embodiment, the same or corresponding descriptions as Figure 1 the embodiment of FIG. 1 will be omitted. Figure 1

[0068] Since the BSS 3 illustrated in Figure 2 is an independent BSS, and does not include an AP, all stations STA6 and STA7 are not connected with the AP. The independent BSS is not allowed to access a distribution system, and forms a self-contained network. In the independent BSS, the respective stations STA6 and STA7 can be directly connected with each other.​

[0069] Figure 3 is a block diagram illustrating a configuration of a station 100 according to an embodiment of the present application. As illustrated in Figure 3 the station 100 according to an embodiment of the present application can include a processor 110, a communication unit 120, a user interface unit 140, a display unit 150, and a memory 160.

[0070] First, the communication unit 120 transmits and receives a wireless signal such as a wireless LAN packet, and can be embedded in the station 100 or provided as an external device. According to an embodiment, the communication unit 120 can include at least one communication module using different frequency bands. For example, the communication unit 120 can include communication modules having different frequency bands such as 2.4 GHz, 5 GHz, 6 GHz, and 60 GHz. According to an embodiment, the station 100 can include a communication module using a frequency band of 7.125 GHz or more, and a communication module using a frequency band of 7.125 GHz or less. Each communication module can perform wireless communication with an AP or an external station according to a wireless LAN standard of a frequency band supported by the corresponding communication module. The communication unit 120 can operate one communication module at a time according to the performance and requirements of the station 100, or operate a plurality of communication modules together at the same time. When the station 100 includes a plurality of communication modules, each communication module can be implemented by independent elements, or a plurality of modules can be integrated into one chip. In an embodiment of the present application, the communication unit 120 can represent a radio frequency (RF) communication module for processing an RF signal.

[0071] 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 a 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 a command of the processor 110 by using various output devices.

[0072] Next, the display unit 150 outputs an image on a display screen. The display unit 150 can output various display objects such as content or a user interface executed by the processor 110, and the like based on a control command of the processor 110. In addition, the memory 160 stores a control program and various result data used in the station 100. The control program can include an access program required for the station 100 to access an AP or an external station.

[0073] The processor 110 of the present application can execute various commands or programs and process data in the station 100. Further, the processor 110 can control the respective units of the station 100 and control data transmission / reception among the units. According to an embodiment of the present application, the processor 110 can execute a program for accessing an AP, which is stored in the memory 160, and receive a communication configuration message transmitted by the AP. Further, the processor 110 can read information about a 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 application can represent a main control unit of the station 100, and according to an embodiment, the processor 110 can represent a control unit for separately controlling certain components (e.g., the communication unit 120, etc.) of the station 100. That is, the processor 110 can 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 application. Detailed embodiments thereof will be described below.

[0074] In Figure 3 , the station 100 illustrated is a block diagram according to an embodiment of the present application, in which separate blocks are illustrated as elements of logically distinguished devices. Accordingly, the elements of the devices can be mounted in a single chip or in a plurality of chips according to the design of the devices. For example, the processor 110 and the communication unit 120 can be implemented when integrated as a single chip, or implemented as separate chips. Further, in an embodiment of the present application, certain components of the station 100, e.g., the user interface unit 140 and the display unit 150, can be selectively provided in the station 100.

[0075] Figure 4 is a block diagram illustrating a configuration of an AP 200 according to an embodiment of the present application. As illustrated in Figure 4 , the AP 200 according to an embodiment of the present application can include a processor 210, a communication unit 220, and a memory 260. In Figure 4 , among the components of the AP 200, a repeated description of a portion that is the same as or corresponds to the components of the station 100 of Figure 2 will be omitted. Figure 2

[0076] Referring to Figure 4 , the AP 200 according to the present application includes a communication unit 220 that operates a BSS in at least one frequency band. As illustrated in Figure 3 ​The communication unit 220 of the AP 200 described in the embodiments can also include a plurality of communication modules using different frequency bands. That is, the AP 200 according to the embodiments of the present application can include two or more communication modules in different frequency bands (for example, 2.4 GHz, 5 GHz, 6 GHz, and 60 GHz) together. Preferably, the AP 200 can include a communication module using a frequency band of 7.125 GHz or more, and a communication module using a frequency band of 7.125 GHz or less. Each communication module can perform wireless communication with a station according to a wireless LAN standard of a frequency band supported by the corresponding communication module. The communication unit 220 can operate one communication module at a time according to the performance and requirements of the AP 200, or operate a plurality of communication modules together at the same time. In the embodiments of the present application, the communication unit 220 can represent a radio frequency (RF) communication module for processing RF signals.

[0077] Next, the memory 260 stores a control program used in the AP 200 and various result data. The control program can include an access program for managing access of stations. In addition, the processor 210 can control the respective units of the AP 200, and control data transmission / reception among the units. According to the embodiments of the present application, the processor 210 can execute a program for accessing stations stored in the memory 260, and transmit a communication configuration message for one or more stations. In this case, the communication configuration message can include information on access priority conditions of the respective stations. In addition, the processor 210 performs access configuration according to an access request of a station. According to the embodiments, the processor 210 can be a modem or a modulator / demodulator for modulating a wireless signal transmitted to the communication unit 220 and demodulating a wireless signal received from the communication unit 220. The processor 210 controls various operations such as wireless signal transmission / reception of the AP 200 according to the embodiments of the present application, and detailed embodiments thereof will be described below.

[0078] Figure 5 is a diagram schematically illustrating a procedure in which a STA sets a link with an AP.

[0079] Reference Figure 5 In general, a link between the STA 100 and the AP 200 is set 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) periodically transmitted, 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).

[0080] 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 the present specification, association basically refers to wireless association, but the present application is not limited thereto, and association can broadly include both wireless association and wired association.

[0081] Meanwhile, an 802.1X-based authentication step (S111) and an IP address acquisition step (S113) via DHCP can be additionally performed. In the present specification, the 802.1X-based authentication step (S111) is a step of authenticating the STA 100 by using the 802.1X-based authentication protocol, and the IP address acquisition step (S113) is a step of acquiring an IP address of the STA 100 by using the DHCP protocol. Figure 5 In the present specification, the authentication server 300 is a server that processes 802.1X-based authentication of the STA 100, and can exist in physical association with the AP 200 or as a separate server.

[0082] Figure 6 FIG. 1 is a diagram illustrating a carrier sense multiple access (CSMA) / collision avoidance (CA) method used in wireless LAN communication.

[0083] A terminal that performs wireless LAN communication checks whether a channel is busy by performing carrier sensing before transmitting data. When a wireless signal having a predetermined strength or greater is sensed, it is determined that the corresponding channel is busy and the terminal delays access to the corresponding channel. This process is called clear channel assessment (CCA), and the level at which it is decided whether the corresponding signal is sensed is called a CCA threshold value. When a wireless signal having a CCA threshold value or greater that the terminal receives indicates the corresponding terminal as a recipient, the terminal processes the received wireless signal. Meanwhile, when no wireless signal is detected in the corresponding channel or a wireless signal having a strength less than the CCA threshold value is detected, it is determined that the channel is idle.

[0084] When the channel is determined to be idle, each terminal with data to transmit performs a backoff procedure after an inter-frame interval (IFS) period, the duration of which depends on the specific terminal, such as after arbitration IFS (AIFS), PCF IFS (PIFS), etc. According to this embodiment, AIFS can be used as a component to replace the existing DCFIFS (DIFS). During the idle period of the channel, each terminal waits while decreasing the slot time by a random number determined by the corresponding terminal, and the terminal that has completely exhausted the slot time attempts to access the corresponding channel. Thus, the interval during which each terminal performs the backoff procedure is called the contention window interval. In this case, the random number is called a backoff counter. That is, the initial value of the backoff counter can be set as an integer, which is the random number obtained by the UE. If the UE detects that the channel is idle during the slot time, the UE can decrement the backoff counter by 1. Furthermore, if the backoff counter reaches 0, the UE can be allowed to perform channel access in the corresponding channel. Therefore, if the channel is idle during the AIFS time and the slot time of the backoff counter, the UE can be allowed to transmit.

[0085] When a specific terminal successfully accesses the channel, it can transmit data through the channel. However, when a terminal attempting to access the channel conflicts with another terminal, the conflicting terminals are each assigned a new random number to re-execute the backoff process. According to an embodiment, a new random number assigned to each terminal can be determined within a range (2*CW), which is twice the range of the previously assigned random numbers (contention window CW) to the corresponding terminal. Simultaneously, each terminal attempts to access the channel again by re-executing the backoff process in the next contention window interval, and in this case, each terminal begins the backoff process from the remaining time slot of the previous contention window interval. In this way, terminals performing wireless LAN communication can avoid mutual conflicts on a specific channel.

[0086] <Examples of various PPDU formats>

[0087] Figure 7 The diagram illustrates an example of the format of the PLCP Protocol Data Unit (PPDU) used in each of the various standard generations. More specifically, Figure 7 The illustration in (a) is based on an embodiment of the conventional PPDU format of 802.11a / g. Figure 7 The illustration in (b) is based on an embodiment using the 802.11ax HE PPDU format, and Figure 7 (c) illustrates an embodiment based on a non-traditional PPDU (i.e., EHTPPDU) of 802.11be. Figure 7 (d) shows the detailed field configuration of RL-SIG and L-SIG, which are commonly used in the PPDU format.

[0088] Referring to Figure 7 (a) of FIG. 1, a preamble of a legacy PPDU includes a legacy short training field (L-STF), a legacy long training field (L-LTF), and a legacy signal field (L-SIG). In an embodiment of the disclosure, the L-STF, the L-LTF, and the L-SIG can be referred to as a legacy preamble.

[0089] Referring to Figure 7 (b) of FIG. 1, a preamble of an HE PPDU further 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 disclosure, the RL-SIG, the HE-SIG-A, the HE-SIG-B, the HE-STF, and the HE-LTF can be referred to as an HE preamble. Detailed configurations of the HE preamble can be modified according to an HE PPDU format. For example, the HE-SIG-B can be used only in an HE MU PPDU format.

[0090] Referring to Figure 7 (c) of FIG. 1, an EHT PPDU further includes a repeated legacy short training field (RL-SIG), a universal signal field (U-SIG), and an extremely high throughput signal A field (EHT-SIG-A), an extremely high throughput signal B field (EHT-SIG-B), an extremely high throughput short training field (EHT-STF), and an extremely high throughput long training field (EHT-LTF) in the legacy preamble. In an embodiment of the disclosure, the RL-SIG, the EHT-SIG-A, the EHT-SIG-B, the EHT-STF, and the EHT-LTF can be referred to as an EHT preamble. Detailed configurations of the non-legacy preamble can be modified according to an EHT PPDU format. For example, the EHT-SIG-A and the EHT-SIG-B can be used only in a part of an EHT PPDU format.

[0091] A 64-FFT OFDM is applied to an L-SIG field included in a preamble of a PPDU, and the L-SIG field includes a total of 64 subcarriers. Among the 64 subcarriers, 48 subcarriers except for a guard subcarrier, a DC subcarrier, and a pilot subcarrier are used for transmission of L-SIG data. A modulation and coding scheme (MCS) of BPSK and a code rate = 1 / 2 is applied to the L-SIG, and thus the L-SIG can include a total of 24 bits of information. Figure 7 (d) of FIG. 1 illustrates a configuration of the 24 bits of information of the L-SIG.

[0092] Referring to Figure 7The L-SIG includes an L_RATE field and an L_LENGTH field. The L_RATE field includes 4 bits and indicates an MCS used for data transmission. Specifically, the L_RATE field indicates one value among 6 / 9 / 12 / 18 / 24 / 36 / 48 / 54 Mbps transmission rates obtained by combining a modulation scheme of BPSK / QPSK / 16-QAM / 64-QAM, etc. and non-efficiency such as 1 / 2, 2 / 3, 3 / 4, etc. The total length of a corresponding PPDU can be indicated by combining information of the L_RATE field and information of the L_LENGTH field. In the non-legacy PPDU format, the L_RATE field is configured as a minimum rate of 6 Mbps.

[0093] The L_LENGTH field has a unit of byte and is allocated 12 bits in total so that up to 4095 is signaled, and the length of the PPDU can be indicated in conjunction with the L_RATE field. The legacy terminal and the non-legacy terminal can interpret the L_LENGTH field in different ways.

[0094] First, a method of interpreting the length of the PPDU by the legacy terminal or the non-legacy terminal using the L_LENGTH field is as follows. When the L_RATE field is set to 6 Mbps, 3 bytes (i.e., 24 bits) can be transmitted within 4us, which is one symbol duration of 64 FFT. Accordingly, the number of 64 FFT-based symbols after the L-SIG is obtained by adding 3 bytes corresponding to the SVC field and the tail field to the value of the L_LENGTH field and dividing it by 3 bytes, which is a transmission amount of one symbol. The length of the corresponding PPDU, i.e., the reception time (i.e., RXTIME) is obtained by multiplying the obtained number of symbols by 4us, which is one symbol duration, and then adding 20us for transmitting the L-STF, the L-LTF, and the L-SIG. This can be represented by Equation 1 below.

[0095] [Equation 1]

[0096]

[0097] 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 up to 5.464ms. The non-legacy terminal transmitting the PPDU should set the L_LENGTH field as shown in Equation 2 below.

[0098] [Equation 2]

[0099]

[0100] Here, TXTIME is the total transmission time of the corresponding PPDU, and is expressed by Equation 3 below. In this case, TX denotes the transmission time of X.

[0101] [Equation 3]

[0102] 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

[0103] Referring to the above equation, the length of the PPDU is calculated based on the upward rounding value of L_LENGTH / 3. Therefore, for a random value of k, three different values of L_LENGTH = {3k+1, 3k+2, 3(k+1)} indicate the same PPDU length.

[0104] Referring to Figure 7 (e), the general SIG (U-SIG) field continues to exist in the EHT PPDU and the WLAN PPDU of the subsequent generation, and is used to classify the generations of the PPDU including 11be. The U-SIG is a 64 FFT-based OFDM 2 symbol, and can transmit a total of 52 bits of information. Among the 52 bits, 43 bits other than 9 bits of CRC / tail are mainly divided into a version-independent (VI) field and a version-dependent (VD) field.

[0105] The VI bits enable the current bit configuration to be maintained in the subsequent, so that even if the PPDU of the next generation 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 a PHY version, UL / DL, BSS color, TXOP, and a reserved field. The PHY version field is 3 bits, and is used to sequentially classify 11be and the subsequent generation wireless LAN standards into each version. The value of 11be is 000b. The UL / DL field identifies whether the PPDU is an uplink / downlink PPDU. The BSS color indicates an identifier of each BSS defined in 11ax, and has a value of 6 bits or more. The TXOP indicates a transmission opportunity duration transmitted in the MAC header, in which the PPDU can infer the length of the TXOP included therein without having to decode the MPDU by adding the TXOP to the PHY header, and the TXOP has a value of 7 bits or more.

[0106] The VD field is signaling information useful only for the 11be version of the PPDU, and can include fields commonly used in any PPDU format such as PPDU format and BW, and fields differently defined for each PPDU format. The PPDU format is a classifier classifying EHT Single User (SU), EHT Multi 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 form of an exponential power of 20*2, can be referred to as a 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 in 320 MHz, signaling can be performed in the form of some 80 MHz punctured. The punctured and modified channel type can be directly signaled in the BW field, or can be signaled using the BW field with a field (e.g., a field within the EHT-SIG field) that occurs after the BW field. If the BW field is configured as 3 bits, a total of 8 BW signaling can be performed, and thus up to 3 signaling can be performed only in the puncturing mode. If the BW field is configured as 4 bits, a total of 16 BW signaling can be performed, and thus up to 11 signaling can be performed in the puncturing mode.

[0107] The field located after the BW field varies according to the type and format of the PPDU, and the MU PPDU and the SU PPDU can be signaled in the same PPDU format, the field for classifying between the MU PPDU and the SU PPDU can be located before the EHT-SIG field, and additional signaling can be performed on the field. The SU PPDU and the MU PPDU both include the EHT-SIG field, but some fields that are not required in the SU PPDU can be compressed. Information about the field on which compression has been applied can be omitted or can have a size smaller than that 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 can be omitted or replaced, or the SU PPDU can have a different configuration in which the user-specific field is replaced, reduced to one, etc.

[0108] Alternatively, the SU PPDU can also include a compression field indicating whether compression is performed, and a part of the field (e.g., the RA field, etc.) can be omitted according to the value of the compression field.

[0109] If a part of the EHT-SIG field of the SU PPDU is compressed, information to be included in the compressed field can 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 a plurality of users, and thus requires the EHT-SIG field to be transmitted after the U-SIG field, and the amount of information transmitted can vary. That is, a plurality of MU PPDUs are transmitted to a plurality of STAs, such that each STA should recognize the location of the RU in 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. Accordingly, the AP should transmit the above information by including the information in the EHT-SIG field. To this end, information for efficient transmission of the EHT-SIG field is signaled in the U-SIG field, and this can correspond to the MCS as a modulation method and / or the number of symbols in the EHT-SIG field. The EHT-SIG field can include information on the size and location of the RU allocated to each user.

[0110] In the case of the SU PPDU, a plurality of RUs can be allocated to the STA, and the plurality of RUs can be continuous or discontinuous. If the RUs allocated to the STA are discontinuous, the STA should recognize the punctured RUs in the middle in order to efficiently receive the SU PPDU. Accordingly, the AP can transmit the SU PPDU including information of the punctured RUs (e.g., a puncturing pattern of the RUs, etc.) in the RUs allocated to the STA. That is, in the case of the SU PPDU, a puncturing pattern field including information indicating a puncturing pattern in a bitmap format, etc., and whether a puncturing pattern is applied can be included in the EHT-SIG field, and the puncturing pattern field can signal a discontinuous channel type occurring within the bandwidth.

[0111] The signaled discontinuous channel type is limited, and indicates the BW and discontinuous channel information of the SU PPDU in combination with the value of the BW field. For example, the SU PPDU is a PPDU transmitted only to a single terminal, such that the STA can recognize the bandwidth allocated to itself via the BW field included in the PPDU, and the SU PPDU can recognize the punctured resources in the allocated bandwidth via the puncturing pattern field of the EHT-SIG field or the U-SIG field included in the PPDU. In this case, the terminal can receive the PPDU in the remaining resource units after excluding the specific channel of the resource units punctured. The plurality of RUs allocated to the STA can be configured by different frequency bands or tones.

[0112] To reduce the signaling overhead of the SU PPDU, only a limited discontinuous channel type is signaled. Puncturing can be performed per 20MHz subchannel, so if puncturing is performed for BWs with a large number of 20MHz subchannels, such as 80, 160, and 320MHz, in the case of 320MHz, the discontinuous channel (if puncturing of only the edge 20MHz is also considered discontinuous) type 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 can act as excessive signaling overhead.

[0113] The present disclosure proposes a technique for signaling the discontinuous channel type of the SU PPDU, and illustrates the discontinuous channel type determined according to the proposed technique. The present disclosure also proposes a technique for signaling each of the puncturing types of the primary 160MHz and the secondary 160MHz in the 320MHz BW configuration of the SU PPDU.

[0114] One embodiment of the present disclosure proposes a technique for differently configuring the PPDU indicated by the preamble puncturing BW value according to the PPDU format signaled in the PPDU format field. Assuming that the BW field is 4 bits, and in the case of the EHT SU PPDU or TB PPDU, 1 symbol of EHT-SIG-A can be additionally signaled after the U-SIG, or EHT-SIG-A can not be signaled at all, so, considering this, it is necessary to completely signal up to 11 puncturing patterns only via the BW field of the U-SIG. However, in the case of the EHT MU PPDU, EHT-SIG-B is additionally signaled after the U-SIG, so up to 11 puncturing patterns can be signaled in a method different from that of the SU PPDU. In the case of the EHT ER PPDU, the BW field can be configured as 1 bit to signal whether the EHT ER PPDU is a PPDU using a 20MHz band or a 10MHz band. Details of the detailed puncturing pattern of each PPDU type will be described later in Figure 11 and Figure 12

[0115] Figure 7 ​(f) illustrates the configuration of the format-specific fields of the VD field when an EHT MU PPDU is indicated in the PPDU format field of the U-SIG. In the case of a MU PPDU, SIG-B is necessary; it is a signaling field used for simultaneous reception by multiple users and can be sent after U-SIG without a separate SIG-A. Therefore, information for decoding SIG-B should be signaled in the U-SIG. These fields include SIG-B MCS, SIG-B DCM, the number of SIG-B symbols, SIG-B compression, and the number of EHT-LTF symbols.

[0116] Figure 8 The illustrations show examples of various Extremely High Throughput (EHT) Physical Protocol Data Unit (PPDU) formats according to embodiments of the present invention, as well as methods for indicating such formats.

[0117] Reference Figure 8 A PPDU can include a preamble and a data portion, and can be classified as an EHT PPDU format based on the U-SIG field included in the preamble. Specifically, the PPDU format field included in the U-SIG field can indicate whether the PPDU is an EHT PPDU.

[0118] Figure 8 (a) shows an example of the EHT SU PPDU format for a single STA. The EHT SU PPDU is a PPDU used for single-user (SU) transmissions between an AP and a single STA, and the EHT-SIG-A field for additional signaling can be located after the U-SIG field.

[0119] Figure 8 (b) shows an example of the EHT trigger-based PPDU format corresponding to the EHT PPDU transmitted based on a trigger frame. The EHT trigger-based PPDU is an EHT PPDU transmitted based on a trigger frame and is an uplink PPDU used in response to the trigger frame. Unlike the EHT SU PPDU, the EHT-SIG-A field is not located after the U-SIG field in the EHT PPDU.

[0120] Figure 8 (c) shows an example of an EHT MU PPDU format corresponding to an EHT PPDU for multiple users. An EHT MU PPDU is a PPDU used to send PPDUs to one or more STAs. In the EHT MU PPDU format, the HE-SIG-B field may follow the U-SIG field.

[0121] Figure 8(d) shows an example of an EHT ER SU PPDU format used for single user transmission with STAs within an extended range. Compared to the EHT SU PPDU described in (a), Figure 8 The EHT ER SU PPDU can be used for single user transmission with a wider range of STAs compared to the EHT SU PPDU described in (a), and the U-SIG field can be repositioned in the time axis.

[0122] Figure 8 The EHT MU PPDU described in (c) can be used by an AP to perform downlink transmission toward multiple STAs. Here, the EHT MU PPDU can include scheduling information so that multiple STAs can simultaneously receive the PPDU transmitted from the AP. The EHT MU PPDU can transmit AID information of the transmitter and / or receiver of the PPDU transmitted via the user-specific field of the EHT-SIG-B to the STAs. Accordingly, multiple terminals that have received the EHT MU PPDU can perform a spatial reuse operation based on the AID information of the user-specific field included in the preamble of the received PPDU.

[0123] Specifically, a resource unit allocation (RA) field of the HE-SIG-B field included in the HE MU PPDU can include information about the configuration of resource units (e.g., a division form of resource units) in a specific bandwidth (e.g., 20 MHz, etc.) of a frequency axis. That is, the RA field can indicate the configuration of resource units divided in the bandwidth for transmission of the HE MU PPDU in order for the STAs to receive the PPDU. Information about the STAs allocated (or designated) to each divided resource unit can be included in the user-specific field of the EHT-SIG-B in order to be transmitted to the STAs. That is, the user-specific field can include one or more user fields corresponding to the respective divided resource units.

[0124] For example, the user field corresponding to at least one resource unit for data transmission among the multiple divided resource units can include an AID of the receiver or transmitter, and the user field corresponding to the remaining resource units not used for data transmission can include a pre-configured null STAID.

[0125] When a wireless communication device communicates by using multiple links, communication efficiency of the wireless communication device can be improved. In this case, a link can be a physical path and can consist of one wireless medium that can be used to deliver a MAC service data unit (MSDU). For example, in a case where a frequency band of one of the links is used by another wireless communication device, the wireless communication device can continue to perform communication through another link. As such, the wireless communication device can usefully use multiple channels. In addition, when the wireless communication device simultaneously performs communication by using multiple links, total throughput can be increased. However, in the existing wireless LAN, it has been stipulated that one wireless communication device uses one link. Therefore, a WLAN operation method using multiple links is needed. This will be described in detail. Figure 9 to Figure 25 A wireless communication method of a wireless communication device using multiple links is described. First, this will be described Figure 9 A specific form of a wireless communication device using multiple links is described.

[0126] Figure 9 A multi-link device according to an embodiment of the disclosure is illustrated.

[0127] A multi-link device (MLD) can be defined for a wireless communication method using multiple links described above. The multi-link device can mean a device having one or more affiliated stations. According to a specific embodiment, the multi-link device can mean a device having two or more affiliated stations. In addition, the multi-link device can exchange a multi-link element. The multi-link element includes information about one or more stations or one or more links. The multi-link element can include a multi-link setup element, which will be described later. In this case, the multi-link device can be a logical entity. Specifically, the multi-link device can have multiple affiliated stations. The multi-link device can be referred to as a multi-link logical entity (MLLE) or a multi-link entity (MLE). The multi-link device can have one media access control (MAC) service access point (SAP) up to a logical link control (LLC). The MLD can also have one MAC data service.

[0128] 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 on multiple different channels. For example, the multiple stations included in the multi-link device can operate on multiple different channels of 2.4 GHz, 5 GHz, and 6 GHz.

[0129] Operations of a multi-link device can be referred to as multi-link operation, MLD operation, or multi-band operation. In addition, when a station attached to a multi-link device is an AP, the multi-link device can be referred to as an AP MLD. In addition, when a station attached to a multi-link device is a non-AP station, the multi-link device can be referred to as a non-AP MLD.

[0130] Figure 9 Operations of a non-AP MLD and an AP-MLD communication are illustrated. Specifically, the non-AP MLD and the AP-MLD respectively communicate by using three links. The AP MLD includes a first AP AP1, a second AP AP2, and a third AP AP3. The 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 a first link Link1. In addition, the second AP AP2 and the second non-AP STA (non-AP STA2) communicate through a second link Link2. In addition, the third AP AP3 and the third non-AP STA (non-AP STA3) communicate through a third link Link3.

[0131] The multi-link operation can include a multi-link setup operation. The multi-link setup can correspond to the association operation of the above-described single-link operation, and can be first performed in the multi-link for frame exchange. The multi-link device can obtain information required for the multi-link setup from a multi-link setup element. Specifically, the multi-link setup element can include capability information associated with the multi-link. In this case, the capability information can include information indicating whether any one of the plurality of devices included in the multi-link device performs transmission and the other device can perform reception at the same time. In addition, the capability information can include information about a link available for each station included in the MLD. In addition, the capability information can include information about a channel available for each station included in the MLD.

[0132] The multi-link setup can be set through negotiation between peer stations. Specifically, the multi-link setup can be performed through communication between stations without communication with an AP. In addition, the multi-link setup can be set through any one link. For example, even though the first link to the third link are set through the multi-link, the multi-link setup can be performed through the first link.

[0133] In addition, a mapping between a traffic identifier (TID) and a link can be set. Specifically, frames corresponding to a TID of a specific value can be exchanged only through a pre-designated link. The mapping between the TID and the link can 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 can be set to transmit frames of a first TID to a plurality of first links, and the second multi-link device can be set to transmit frames of a second TID to the first link. Further, there can be a default setting for the mapping between the TID and the link. Specifically, in the case where no additional setting is made in a multi-link setting, the multi-link device can exchange frames corresponding to a TID at each link according to the default setting. In this case, the default setting can be to exchange all TIDs in any one link.

[0134] The TID will be described in detail. The TID is an ID used to classify traffic and data in order to support quality of service (QoS). In addition, the TID can be used or assigned in a layer higher than the MAC layer. Further, the TID can indicate a traffic class (TC) or a traffic stream (TS). Furthermore, the TID can be classified into 16 types. For example, the TID can be designated as one of values in the range of 0 to 15. The TID value to be used can be designated differently according to an access policy and a channel access or medium access method. For example, in the case of using enhanced distributed channel access (EDCA) or channel access based on hybrid coordination function contention (HCAF), a value in the range of 0 to 7 can be assigned to the TID. In the case of using EDCA, the TID can indicate a user priority (UP). In this example, the UP can be designated based on the TC or the TS. The UP can be assigned in a layer higher than the MAC. In addition, in the case of using HCF controlled channel access (HCCA) or SPCA, a value in the range of 8 to 15 can be assigned to the TID. In the case of using HCCA or SPCA, the TID can indicate a TSID. In addition, in the case of using HEMM or SEMM, a value in the range of 8 to 15 can be assigned to the TID. In the case of using HEMM or SEMM, the TID can indicate a TSID.

[0135] The UPs and ACs can be mapped. The ACs can be tags for providing QoS in EDCA. The ACs can be tags for indicating EDCA parameter sets. The EDCA parameters or EDCA parameter sets can be parameters for EDCA channel contention. The QoS stations can use the ACs to guarantee QoS. In addition, the ACs can include AC_BK, AC_BE, AC_VI, and AC_VO. The AC_BK, AC_BE, AC_VI, and AC_VO can indicate background, best effort, video, and voice, respectively. In addition, each of the AC_BK, AC_BE, AC_VI, and AC_VO can be classified as a dependent AC. For example, the AC_VI can be subdivided into AC_VI primary and AC_VI secondary. Also, the AC_VO can be subdivided into AC_VO primary and AC_VO secondary. In addition, the UPs or TIDs can be mapped to the ACs. For example, the UPs or TIDs having values 1, 2, 0, 3, 4, 5, 6, and 7 can be mapped to the AC_BK, AC_BK, AC_BE, AC_BE, AC_VI, AC_VI, AC_VO, and AC_VO, respectively. In addition, the UPs or TIDs having values 1, 2, 0, 3, 4, 5, 6, and 7 can be mapped to the AC_BK, AC_BK, AC_BE, AC_BE, AC_VI secondary, AC_VI primary, AC_VO primary, and AC_VO secondary, respectively. In addition, the UPs or TIDs having values 1, 2, 0, 3, 4, 5, 6, and 7 can sequentially have high priority. That is, 1 indicates low priority, and 7 indicates high priority. Accordingly, the AC_BK, AC_BE, AC_VI, and AC_VO can sequentially have high priority. In addition, the AC_BK, AC_BE, AC_VI, and AC_VO can correspond to AC indices (ACIs) 0, 1, 2, and 3, respectively. Due to these characteristics of the TIDs, the mapping between the TIDs and the links can indicate the mapping between the ACs and the links. In addition, the mapping between the links and the ACs can indicate the mapping between the TIDs and the links.

[0136] As described above, the TIDs can be mapped to each of the plurality of links. The mapping can designate links capable of exchanging traffic corresponding to a predetermined TID or AC. In addition, the TIDs or ACs transmittable for each transmission direction in the links can be designated. As described above, there can be a default configuration for the mapping between the TIDs and the links. Specifically, in the case where there is no additional configuration for the multi-link configuration, the multi-link device can exchange frames corresponding to the TIDs in each link according to the default configuration. In this instance, the default configuration can exchange all of the TIDs in any one link. Any TID or AC at any point in time can always be mapped to at least any one link. The management frames and control frames can be transmitted in all of the links.

[0137] In case a link is mapped to a TID or an AC, only data frames corresponding to the TID or the AC mapped to the corresponding link can be transmitted in the corresponding link. Thus, in case a link is mapped to a TID or an AC, frames not corresponding to the TID or the AC mapped to the corresponding link can not be transmitted in the corresponding link. In case a link is mapped to a TID or an AC, ACKs can also be transmitted based on the link to which the TID or the AC is mapped. For example, a block ACK protocol can be determined based on the mapping between TIDs and links. According to another embodiment, the mapping between TIDs and links can be determined based on a block ACK protocol. In particular, a block ACK protocol can be set for TIDs mapped to a predetermined link.

[0138] QoS can be guaranteed via the above-described mapping between TIDs and links. In particular, ACs or TIDs having a high priority can be mapped to a link operated by a relatively small number of stations or a link having good channel conditions. In addition, via the above-described mapping between TIDs and links, stations can be enabled to maintain a power saving state during a long period of time.

[0139] Figure 10 FIG. 1 is a diagram illustrating a case in which transmissions in different links are simultaneously performed in a multi-link operation according to an embodiment of the present disclosure.

[0140] According to implementation of the multi-link device, the multi-link device can perform transmission in multiple links simultaneously, can perform reception in multiple links simultaneously, or can perform transmission in any one link and can not support reception in another link simultaneously. This is because reception or transmission performed in any one link can affect reception or transmission performed in another link. Specifically, transmission in one link can act as interference in another link. The interference from one link of a single multi-link device that is applied to another link can be referred to as internal leakage. When a frequency interval between the links is small, the internal leakage can be high. When transmission is performed in any one link, transmission can be performed in another link in a case where a magnitude of the internal leakage is not too high. In a case where the magnitude of the internal leakage is too high when transmission is performed in any one link, transmission can not be performed in another link. As described above, a case where the multi-link device performs transmission in multiple links simultaneously, the multi-link device performs transmission in any one link and performs reception in another link simultaneously, or the multi-link device performs reception in multiple links simultaneously can be referred to as STR (Simultaneous Transmission and Reception, Simultaneous Transmission and Reception). As described above, the multi-link device can not support STR. According to another detailed embodiment, the multi-link device can support STR with limitations. Specifically, the multi-link device can support STR only under predetermined conditions. For example, in a case where the multi-link device operates using a single radio, the multi-link device can not be able to perform STR. In addition, in a case where the multi-link device operates using a single antenna, the multi-link device can not be able to perform STR. In addition, in a case where a magnitude of the internal leakage is detected to be greater than or equal to a predetermined magnitude, the multi-link device can not be able to perform STR.

[0141] The station can exchange information associated with the STR capability of the station with another station. Specifically, the station can exchange information associated with whether the station capability of performing transmission or reception in multiple links is limited with another station. Specifically, the information associated with whether the capability of performing transmission or reception in multiple links is limited can indicate whether simultaneous transmission in multiple links, simultaneous reception in multiple links, or simultaneous transmission and reception in multiple links can be performed. In addition, the information associated with whether the capability of performing transmission or reception in multiple links is limited can be information indicated for each level. Specifically, the information associated with whether the capability of performing transmission or reception in multiple links is limited can be information indicating a level representing a magnitude of internal leakage. According to a detailed embodiment, the information indicating a level representing a magnitude of internal leakage can be information indicating a level representing a magnitude of interference due to internal leakage. According to another detailed embodiment, it can be information indicating a level representing a frequency interval between links that can affect internal leakage. In addition, the information indicating a level representing a magnitude of internal leakage can be information indicating a relationship between internal leakage and a frequency interval between links for each level.

[0142] In Figure 10 In this case, the first station (STA1) can not receive the response (ACK for Data1) to the first data (Data1). In the case where the second station (STA2) performs transmission in the second link (Link2), reception performed by the first station (STA1) in the first link (Link1) can be interfered with. For example, the second station (STA2) can transmit first data (Data1) in the second link (Link2), and the first AP (AP1) transmits a response (ACK for Data1) to the first data (Data1) to the first station (STA1). The second station (STA2) transmits second data (Data2) in the second link (Link2). In this case, the transmission time of the second data (Data2) and the transmission time of the response (ACK for Data1) to the first data (Data1) can overlap. In this example, interference in the first link (Link1) can occur due to transmission to the second station (STA2) in the second link (Link2). Therefore, the first station (STA1) can not receive the response (ACK for Data1) to the first data (Data1). Figure 10(a) illustrates a case where transmission is started at the same time in multiple links. However, as Figure 10 (b) shows, transmission can be started at different points in time in multiple links.

[0143] Specifically, the multi-link device can perform channel access, e.g., backoff, independently in multiple links. In this example, simultaneous transmission in multiple links can be started when the backoff counter reaches 0 in multiple links. According to another detailed embodiment, in a case where the backoff counter reaches 0 in any one link of the multi-link device, the multi-link device can perform energy detection (ED) only in a link different from the corresponding link, and can perform channel access. In a case where energy greater than or equal to a predetermined value is not detected, the multi-link device can perform channel access in the link where energy detection is performed. With the above, the multi-link device can start simultaneous transmission in multiple links. The value of the threshold for energy detection can be lower than the value of the threshold for determining whether to decrease the backoff counter. In addition, in determining whether to decrease the backoff counter, the station can detect any type of signal as well as a wireless LAN signal. In addition, in the above energy detection, the station can detect any type of signal as well as a wireless LAN signal. Internal leakage can not be detected via a wireless LAN signal. In this example, the station can sense a signal detected due to internal leakage via energy detection. In addition, as described above, the value of the threshold for energy detection can be lower than the value of the threshold for determining whether to decrease the backoff counter. Thus, although transmission is being performed in another link, the multi-link device can decrease the backoff counter in any one link, as Figure 10 (a) and Figure 10 (b) shown.

[0144] An operation method in a case where the STR of the multi-link device is restricted will be described with reference to Figure 11 to 25 However, embodiments of the present disclosure can be applied even in a case where the STR of the multi-link device is not restricted.

[0145] With reference to Figure 11 to 15 , a case where multiple PPDUs are transmitted or can be transmitted simultaneously in multiple links will be described. In addition, when the STR is not available in multiple links where multiple PPDUs are transmitted, the embodiments described with reference to Figure 11 to Figure 15 may be applicable. In a case where the multi-link device receiving multiple PPDUs performs transmission in any one link but cannot perform reception in another link, the embodiments described with reference to Figure 11 to 15 may be applicable. In a case where the multi-link device transmitting multiple PPDUs performs transmission in any one link but cannot perform reception in another link, the embodiments described with reference to Figure 11 to 15 may be applicable.

[0146] Figure 11 is a diagram illustrating an operation of terminating transmission in multiple links by a multi-link device simultaneously according to an embodiment of the disclosure.

[0147] In a case where a multi-link device performs transmission in multiple links, the multi-link device can terminate simultaneous transmission in the multiple links. Specifically, the end time of a PPDU transmitted in the multiple links can be the same. In addition, such embodiments can be applied to a case where transmission is not started simultaneously in addition to a case where transmission is started simultaneously by the multi-link device in the multiple links. Such an operation can be used for a multi-link device that cannot perform transmission and reception simultaneously. For example, this can be an operation for a case where a multi-link device that receives multiple PPDUs cannot perform transmission and reception simultaneously. Alternatively, this can be an operation for a case where a multi-link device that transmits multiple PPDUs cannot perform transmission and reception simultaneously. Specifically, as Figure 10 (a) shown, this can prevent the failure of reception of an ACK in another link while transmission is performed in any one link. Accordingly, in a case where a multi-link device does not support performing reception in another link while transmission is performed in any one link, the multi-link device can terminate simultaneous transmission in multiple links.

[0148] When a response frame to transmission by a multi-link device is transmitted in one link, the multi-link device can cause transmission in another link not to be performed. Specifically, based on whether a frame transmitted by the multi-link device requests an ACK, the multi-link device can determine the end time of transmission in multiple links. Based on whether a frame transmitted by the multi-link device requests an ACK, the multi-link device can terminate simultaneous transmission in multiple links. That is, based on whether a frame included in at least one of multiple PPDUs requests an ACK, simultaneous transmission in multiple links can be terminated. Whether a frame requests an ACK can be determined according to an ACK policy. For example, in a case where the ACK policy of a frame is "no ACK", the multi-link device can determine that the frame does not request an ACK. In addition, in a case where the type and subtype of a frame correspond to an "action no ACK frame", the multi-link device can determine that the frame does not request an ACK. The ACK policy as well as the type and subtype of a frame can be indicated by a MAC header of the frame. As Figure 11 As shown in the embodiment of FIG. 2, a frame requesting an ACK can be a data frame. Specifically, the frame requesting an ACK can be a QoS data frame. This is because information indicating an ACK policy can be included in a QoS data frame.

[0149] In a case where a multi-link device performs transmission in multiple links, the multi-link device can terminate simultaneous transmission in the multiple links. Specifically, the end time of a PPDU transmitted in the multiple links can be the same. In addition, such embodiments can be applied to a case where transmission is not started simultaneously in addition to a case where transmission is started simultaneously by the multi-link device in the multiple links. Such an operation can be used for a multi-link device that cannot perform transmission and reception simultaneously. For example, this can be an operation for a case where a multi-link device that receives multiple PPDUs cannot perform transmission and reception simultaneously. Alternatively, this can be an operation for a case where a multi-link device that transmits multiple PPDUs cannot perform transmission and reception simultaneously. Specifically, as Figure 11In embodiments according to the present disclosure, a multi-link device can not be able to perform reception in another link while performing transmission in any one link. A first station (STA1) and a second station (STA2) of the multi-link device can transmit first data (Data1) and second data (Data2), respectively. The first station (STA1) and the second station (STA2) can terminate transmission of the first data (Data1) and the second data (Data2), respectively, at the same time. Thus, a response to the first data (Ack for Data1) and a response to the second data (Ack for Data2) can be transmitted at the same time without internal leakage, and the multi-link device can receive the response to the first data (Ack for Data1) and the response to the second data (Ack for Data2) at the same time.

[0150] Figure 12 is a diagram illustrating an operation in which a multi-link device according to embodiments of the present disclosure first terminates transmission in any one link when performing transmission in multiple links.

[0151] In a case where the multi-link device starts transmission in another link while performing transmission in any one link or starts simultaneous transmission in multiple links, the multi-link device can not be allowed to terminate transmission in the other link after transmission in any one link. Thus, the multi-link device can terminate transmission in another link earlier than or at the same time as transmission in any one link. In particular, in a case where the multi-link device starts transmission in another link while performing transmission in any one link and a response frame with respect to a frame transmitted in the other link is not expected, the multi-link device can terminate transmission in the other link before or at the same time as transmission in the any one link. In this example, the response frame can be an immediate response frame. The immediate response frame can correspond to a case where an interval between a frame and a response frame falls within a predetermined time interval. In this example, the predetermined time interval can be SIFS. In addition, the case where the response frame is not expected can include a case where the response frame has been referred to as a response frame with respect to a frame transmitted in the other link. Figure 11The described no-ACK requesting case. Specifically, the frame requesting an immediate response frame can include a frame requesting an ACK. In addition, the frame requesting an immediate response can include a frame triggering an uplink transmission. In addition, the frame requesting an immediate response can include a QoS data frame requesting an immediate response. In addition, the frame requesting an immediate response can include a control frame requesting an immediate response. In addition, the frame requesting an immediate response can include a management frame requesting an immediate response. In addition, the case where the PPDU includes a frame requesting an immediate response can be the case where at least one of the frames included in the PPDU requests an immediate response. The case where the PPDU includes a frame requesting an immediate response from a station can be the case where at least one of the frames included in the PPDU requests an immediate response from a station. In the case where the multi-link device performs a transmission of a response frame that is not expected in any one of the links, the multi-link device can be allowed not to terminate the transmission in the other link before terminating the transmission in any one of the links. Thus, in the case where the multi-link device performs a transmission of a response frame that is not expected in any one of the links, the multi-link device can terminate the transmission in the other link after terminating the transmission in any one of the links. In the case where the multi-link device performs a transmission of a response frame that is not expected in any one of the links and a frame transmitted in the other link requests an immediate frame, the multi-link device can be allowed not to terminate the transmission in the other link before terminating the transmission in any one of the links. In this instance, the response frame can be an immediate response frame. Thus, in the case where the multi-link device transmits only a plurality of PPDUs including no frame requesting a response or a single PPDU including a frame requesting a response and a PPDU requesting a response at the same time, the multi-link device can not terminate the transmission of the plurality of PPDUs at the same time. In this instance, the multi-link device can transmit the plurality of PPDUs in a manner that the end time of the transmission of the PPDUs including no frame requesting a response is not later than the end time of the transmission of the PPDUs including a frame requesting a response.

[0152] In Figure 12 In an embodiment, the multi-link device can not be able to perform reception in the other link when performing transmission in any one of the links. A first station (STA1) and a second station (STA2) of the multi-link device can transmit first data (Data1) and second data (Data2), respectively. When the first station (STA1) transmits the first data (Data1) to a first AP (AP1), the second station (STA2) starts to transmit the second data (Data2). The second data (Data2) can not request an ACK. The second station (STA2) terminates the transmission of the second data (Data2) before the first station (STA1) terminates. Thus, when the first station (STA1) receives an ACK for the first data (Ack for Data1), the transmission of the second station (STA2) can not interfere with the first station (STA1).

[0153] In addition, the above embodiments can be applied to situations where a multi-link device cannot perform reception on another link while transmission is being performed on any one link.

[0154] Figure 13 This is a diagram illustrating a multi-link device delaying a transmission in another link when a transmission is performed in either link, according to an embodiment of the present disclosure.

[0155] Multi-link devices may not perform simultaneous transmission across multiple links. Specifically, a multi-link device may perform transmission only on a single link among multiple links. For example, if a multi-link device performs transmission on any one link and cannot receive on another, it may be able to perform transmission only on one of the multiple links. In such embodiments, the multi-link device may defer transmission when performing channel access. The channel access described herein may be referred to as including [the categories already referenced]. Figure 6 The described backoff process pertains to channel access. Specifically, a multi-link device can postpone transmissions on all links except the single link where transmission is to be performed. For example, the multi-link device can perform a backoff process on all of these links. In this example, the multi-link device can perform transmission on the link whose backoff counter first reaches 0, and can reset the backoff counters on the remaining links. Alternatively, if the backoff counters on multiple links reach 0, the multi-link device can perform transmission on any of the multiple links. In this example, the multi-link device can randomly select any of the multiple links and perform transmission on the selected link. Additionally, the multi-link device can reset the backoff counters on the unselected links. Resetting means setting a value randomly selected by the multi-link device within the CW to the backoff counter. Furthermore, the multi-link device can reset the CW of links where transmission is not performed. Specifically, the multi-link device can set the CW of links where transmission is not performed to CWmin, where CWmin is the minimum value of the CW. This type of embodiment can be applied to situations where the multi-link device performs transmission on any one link and cannot perform reception on another link.

[0156] According to another detailed embodiment, the multi-link device can determine a method for performing channel access across multiple links based on whether it performs transmission on any one link and cannot perform reception on another link. Specifically, if the multi-link device performs transmission on any one link and cannot perform reception on another link, the multi-link device may not independently perform channel access across multiple links. Conversely, if the multi-link device performs transmission on any one link and can perform reception on another link, the multi-link device can independently perform channel access across multiple links.

[0157] likeFigure 11 to 12 As described above, the multi-link device can control the length of the PPDU according to the simultaneous capability condition to satisfy the constraint condition. In this instance, in a case where the multi-link device is difficult to complete the control of the length of the PPDU until the transmission time arrives, the multi-link device can perform the transmission in any one of the plurality of links. In addition, in a case where the allowed transmission time in any one link is shorter than the traffic that needs to be transmitted in the corresponding link, the multi-link device can postpone the transmission in the corresponding link. For example, according to an embodiment of Figure 11 and Figure 12 , the allowed transmission time in the link can be shorter than the traffic that needs to be transmitted in the corresponding link.

[0158] Figure 13 The multi-link device in an embodiment of

[0159] In the above-described embodiments, the multi-link device resets the backoff counter when postponing the transmission. According to another detailed embodiment, when the multi-link device postpones the transmission, the multi-link device can maintain the value of the backoff counter as it is. Through the above, it is possible to guarantee the fairness of the transmission between the links that can be deteriorated due to the postponing of the transmission.

[0160] Figure 14 is a diagram illustrating an operation in which the multi-link device according to an embodiment of the disclosure terminates the transmission in any one link first when the multi-link device performs the transmission in a plurality of links.

[0161] In a case where the multi-link device performs the transmission in a plurality of links, as described in an embodiment with reference to Figure 11 , the multi-link device can terminate the transmission in the plurality of links at the same time. Specifically, the multi-link device can terminate the PPDU transmission in the plurality of links at the same time. The termination of the transmission of a plurality of PPDUs at the same time can be referred to as aligning the ends of the PPDUs. In addition, the ends of a plurality of PPDUs are considered to be aligned in a case where the difference between the transmission end times of the plurality of PPDUs is less than or less than or equal to a threshold value. In this instance, the threshold value can be a predetermined value. Specifically, the threshold value can be a value set based on SIFS. In addition, the threshold value can be a value set based on SIFS and a signal extension length. For example, the threshold value can be a value obtained by dividing the sum of SIFS and the signal extension length by 2. In this instance, the threshold value can be 8us.

[0162] In a case where a multi-link device transmits multiple PPDUs to another multi-link device in multiple links, the multi-link device can align ends of the multiple PPDUs. In a case where a multi-link device transmits multiple PPDUs to another multi-link device in multiple links, the multi-link device can align ends of two or more PPDUs. In this instance, the multi-link device can be referred to as a transmitter multi-link device, and the other multi-link device can be referred to as a receiver multi-link device. The transmitter multi-link device or the receiver multi-link device can be a multi-link device that does not support STR or supports STR with limitations. The multi-link device that does not support STR or supports STR with limitations can be referred to as a non-STR multi-link device. In addition, the multi-link device that supports STR can be referred to as an STR multi-link device.

[0163] The receiver multi-link device can be a non-STR multi-link device. In a case where the transmitter multi-link device transmits multiple PPDUs to the non-STR multi-link device in multiple links, the transmitter multi-link device can align ends of the multiple PPDUs. The non-AP multi-link device can be a non-STR multi-link device. Accordingly, in a case where the AP multi-link device transmits multiple PPDUs to the non-STR non-AP multi-link device in multiple links, the AP multi-link device can align ends of the multiple PPDUs.

[0164] The transmitter multi-link device can be a non-STR multi-link device. In a case where the non-STR multi-link device transmits multiple PPDUs to the receiver multi-link device in multiple links, the transmitter multi-link device can align ends of the multiple PPDUs. Accordingly, in a case where the non-STR non-AP multi-link device transmits multiple PPDUs to the AP multi-link device in multiple links, the non-STR non-AP multi-link device can align ends of the PPDUs.

[0165] In such embodiments, a transmission direction from an AP or an AP multi-link device to a non-AP STA or a non-AP multi-link device can be referred to as a downlink (DL). In addition, a transmission direction from a non-AP STA or a non-AP multi-link device to an AP or an AP multi-link device can be referred to as an uplink (UL). A frame and a PPDU transmitted by the AP or the AP multi-link device to the non-AP STA or the non-AP multi-link device can be referred to as a DL frame and a DL PPDU, respectively. A frame and a PPDU transmitted by the non-AP STA or the non-AP multi-link device to the AP or the AP multi-link device can be referred to as an UL frame and an UL PPDU, respectively.

[0166] The above-described embodiments of aligning ends of multiple PPDUs can be applied to a case where only at least one of the multiple PPDUs includes a frame requesting an immediate response.

[0167] In the above embodiments, a plurality of PPDUs can be transmitted to a single multi-link device in a plurality of links. Specifically, a receiver multi-link device can receive a plurality of PPDUs from a plurality of stations belonging to a single multi-link device in a plurality of links. For example, the receiver multi-link device can operate in a first link and a second link. A first station of the receiver multi-link device operates in the first link, and a second station of the receiver multi-link device operates in the second link. When a first PPDU is transmitted to the first station in the first link, a second PPDU is transmitted to the second station in the second link, and in a case where each of the first PPDU and the second PPDU includes a frame requesting an immediate response, an end of the first PPDU and an end of the second PPDU can be aligned.

[0168] In the above embodiments, a case where a plurality of PPDUs are transmitted in a plurality of links can be simultaneous transmission of the plurality of PPDUs. In addition, a case where a plurality of PPDUs are transmitted in a plurality of links can be simultaneous transmission at any point in time. Although transmission start times of the plurality of PPDUs are different from each other, simultaneous transmission of the plurality of PPDUs can have a point in time at which the PPDUs are transmitted simultaneously. Although transmission end times of the plurality of PPDUs are different from each other, simultaneous transmission of the plurality of PPDUs can have a point in time at which the PPDUs are transmitted simultaneously.

[0169] According to other detailed embodiments, in a case where at least one PPDU among a plurality of PPDUs transmitted in a plurality of links includes a frame having a high priority, a multi-link device can not align ends of the plurality of PPDUs. In this example, the frame having the high priority can be a frame having a higher priority than a predetermined priority. In addition, the frame having the high priority can be a predetermined frame. Through the above, the multi-link device can improve transmission efficiency of the frame having the high priority.

[0170] In the above embodiments, in a case where only some of a plurality of PPDUs satisfy a predetermined condition, a multi-link device can align ends of the some of the plurality of PPDUs satisfying the predetermined condition. In a case where the multi-link device transmits a plurality of PPDUs, the multi-link device can align ends of a plurality of PPDUs among the plurality of PPDUs including a frame requesting an immediate response. For example, only two of a plurality of PPDUs include a frame requesting an immediate response, the multi-link device can align ends of only the two of the plurality of PPDUs including the frame requesting the immediate response. In these embodiments, the multi-link device can not align ends of PPDUs not including the frame requesting the immediate response with the ends of the plurality of PPDUs including the frame requesting the immediate response. Specifically, the multi-link device can perform transmission in a manner that the end of the PPDU not including the frame requesting the immediate response is not later than the end of the PPDU including the frame requesting the immediate response.

[0171] InFigure 14 In an embodiment of the disclosure, an AP multi-link device can include a first AP (AP1), a second AP (AP2), and a third AP (AP3). In addition, a non-AP multi-link device can include a first station (STA1), a second station (STA2), and a third station (STA3). The AP multi-link device or the non-AP multi-link device can be a non-STR multi-link device. Specifically, the non-AP multi-link device can be a non-STR multi-link device. The first AP (AP1), the second AP (AP2), and the third AP (AP3) can transmit a first PPDU (PPDU1), a second PPDU (PPDU2), and a third PPDU (PPDU3) to the first station (STA1), the second station (STA2), and the third station (STA3) via a first link (Link1), a second link (Link2), and a third link (Link3), respectively. The first PPDU (PPDU1) can include first data (Data1) requesting an immediate response, and the second PPDU (PPDU2) can include second data (Data2) requesting an immediate response. The third PPDU (PPDU3) can include only third data (Data3) not requesting an immediate response. The AP multi-link device can align an end of the first PPDU (PPDU1) with an end of the second PPDU (PPDU2), and can not align an end of the third PPDU (PPDU3) with the ends of the first PPDU (PPDU1) and the second PPDU (PPDU2). In this instance, an end time of the third PPDU (PPDU3) can be the same as or earlier than end times of the first PPDU (PPDU1) and the second PPDU (PPDU2).

[0172] Figure 15 is a diagram illustrating an operation of first terminating transmission in any one link by a multi-link device in a case where the multi-link device performs transmission in a plurality of links according to another embodiment of the disclosure.

[0173] In a case where a transmitter multi-link device transmits a plurality of PPDUs to a receiver multi-link device in a plurality of links, the transmitter multi-link device can determine a transmission length of each of the plurality of PPDUs depending on whether each corresponding PPDU includes a frame requesting an immediate response. Specifically, the transmitter multi-link device can determine such that the end of transmission of a PPDU not including a frame requesting an immediate response can be performed simultaneously or earlier than the end of transmission of a PPDU including a frame requesting an immediate response. Accordingly, the transmitter multi-link device can determine such that the end of transmission of a PPDU including a frame requesting an immediate response can be performed simultaneously or later than the end of transmission of a PPDU not including a frame requesting an immediate response. In this embodiment, the transmitter multi-link device or the receiver multi-link device can be a non-STR multi-link device.

[0174] In Figure 15 embodiments, an AP multi-link device can include a first AP (AP1) and a second AP (AP2). In addition, a non-AP multi-link device can include a first station (STAl) and a second station (STA2). The AP multi-link device or the non-AP multi-link device can be a non-STR multi-link device. Specifically, the non-AP multi-link device can be a non-STR multi-link device. The first AP (AP1) and the second AP (AP2) can transmit a first PPDU (PPDU1) and a second PPDU (PPDU2) to the first station (STAl) and the second station (STA2) via a first link (Link1) and a second link (Link2), respectively. The first PPDU (PPDU1) can include first data (Data1) requesting an immediate response, and the second PPDU (PPDU2) can include only second data (Data2) not requesting an immediate response. In this instance, the second data (Data2) can be an A-MPDU including only MPDUs not requesting an immediate response. In addition, a receiver of the first data (Data1) can be the first station (STAl), and a receiver of the second data (Data2) can be the second station (STA2). In addition, the first PPDU (PPDU1) and the second PPDU (PPDU2) can be one of an SU PPDU or an MU PPDU. The AP multi-link device can transmit the first PPDU (PPDU1) and the second PPDU (PPDU2) in a manner that a transmission end time of the second PPDU (PPDU2) is the same as or earlier than a transmission end time of the first PPDU (PPDU1). Embodiments described with reference to Figure 15 may be applied regardless of a transmission start time of the PPDU. Specifically, as shown in (a) of Figure 15 , a transmission start of the first PPDU (PPDU1) can be earlier than a transmission start of the second PPDU (PPDU2). In addition, as shown in (b) of Figure 15 , a transmission start of the first PPDU (PPDU1) can be later than a transmission start of the second PPDU (PPDU2).

[0175] Via Figure 10 to Figure 15 embodiments, a problem that can be caused by internal leakage can be overcome.

[0176] A mapping between a link and a TID can be configured as shown in embodiments described with reference to Figure 9 . In this instance, detailed operation methods of a multi-link device will be described with reference to Figure 16 to Figure 20 .

[0177] Figure 16 is a diagram illustrating that a multi-link device according to an embodiment of the disclosure operates using a mapping between a link and a TID.

[0178] In an embodiment of the disclosure, although there is a mapping between TIDs and links, a multi-link device can transmit traffic without following the mapping between TIDs and links. Specifically, MPDUs corresponding to TIDs not mapped to any one of the links can be transmitted via the corresponding links. For example, an aggregated MPDU (A-MPDU) transmitted in any one of the links can be an aggregation of MPDUs corresponding to TIDs mapped to the corresponding link and MPDUs corresponding to TIDs not mapped to the corresponding link. In addition, a PPDU transmitted in any one of the links can include MPDUs corresponding to TIDs mapped to the corresponding link and MPDUs corresponding to TIDs not mapped to the corresponding link. As described above, as an exception to the mapping between TIDs and links.

[0179] Specifically, in the case where a limit on a transmission end time in any one of the links is applied, frames corresponding to TIDs not mapped to the corresponding link can be transmitted in the corresponding link. According to a detailed embodiment, in the case where a multi-link device performs, the multi-link device can set a transmission end time of a second link based on a transmission end time of a first link. In this instance, the multi-link device can transmit MPDUs corresponding to TIDs mapped to the second link and MPDUs corresponding to TIDs not mapped to the second link together. In addition, the multi-link device can compare values of TIDs not mapped to the link with values of TIDs mapped to the link, and based on a result of the comparison, it can determine whether to transmit MPDUs corresponding to TIDs mapped to the second link and MPDUs corresponding to TIDs not mapped to the second link together. For example, in the case where the values of TIDs not mapped to the link are greater than the values of TIDs mapped to the link, the multi-link device can transmit MPDUs corresponding to TIDs mapped to the link and MPDUs corresponding to TIDs not mapped to the second link together. According to another detailed embodiment, in the case where the values of TIDs not mapped to the link are less than the values of TIDs mapped to the link, the multi-link device can transmit MPDUs corresponding to TIDs mapped to the link and MPDUs corresponding to TIDs not mapped to the second link together.

[0180] According to another detailed embodiment, the multi-link device can compare priorities corresponding to TIDs not mapped to the link with priorities corresponding to TIDs mapped to the link, and based on a result of the comparison, it can determine whether to transmit MPDUs corresponding to TIDs mapped to the link and MPDUs corresponding to TIDs not mapped to the link together in the corresponding link. In this instance, the priorities can be traffic categories (TCs) or access categories (ACs).

[0181] An AP multi-link device can include a first AP (AP1) and a second AP (AP2). Also, a non-AP multi-link device can include a first station (STAl) and a second station (STA2). A first TID (TID 0) and a third TID (TID 2) can be mapped to a first link (Linkl), and a second TID (TID 1) can be mapped to a second link (Link2). The non-AP multi-link device can transmit, in the second link (Link2), an MPDU corresponding to the third TID (TID 2) that is not mapped to the second link (Link2). Specifically, the non-AP multi-link device can transmit, in the second link (Link2), a PPDU including an MPDU mapped to the first TID (TID 0) that is mapped to the second link (Link2) and an MPDU corresponding to the third TID (TID 2) that is not mapped to the second link (Link2). In this instance, the non-AP multi-link device satisfies a predetermined condition, whereby the non-AP multi-link device can transmit, in the second link (Link2), the MPDU corresponding to the third TID (TID 2) that is not mapped to the second link (Link2). Specifically, since the value of the third TID (TID 2) is greater than the value of the second TID (TID 1), the non-AP multi-link device can transmit, in the second link (Link2), the MPDU corresponding to the third TID (TID 2) that is not mapped to the second link (Link2). Also, in the case where the non-AP multi-link device aligns the transmission end in the first link with the transmission end in the second link, the traffic that needs to be transmitted in the second link (Link2) is insufficient, whereby the non-AP multi-link device can transmit, in the second link (Link2), the MPDU corresponding to the third TID (TID 2) that is not mapped to the second link (Link2).

[0182] In the case where a multi-link device selects a link to be used for transmission among a plurality of links, the multi-link device can transmit, in the selected link, a frame corresponding to a TID that is not mapped to the selected link. Specifically, in the case where a multi-link device selects a link to be used for transmission among a plurality of links, the multi-link device can transmit, in the selected link, a frame corresponding to a TID that is mapped to a link that is not selected among the plurality of links. Specifically, this embodiment can be applied to the description of the embodiments with reference to Figure 13 the described embodiments.

[0183] In these embodiments, the problem to be solved can be to determine a link in which a multi-link device is to transmit a response to a frame corresponding to a TID that is not mapped to a link. In the link in which the frame corresponding to the TID that is not mapped to the link is transmitted, the multi-link device can transmit a response to the corresponding frame. In this instance, the response to the corresponding frame can be an ACK. For example, Figure 16The AP multi-link device in embodiments of the present disclosure can transmit an ACK associated with a frame corresponding to the first TID (TID 0) in the first link (Link1), and can transmit an ACK associated with a frame corresponding to the third TID (TID 2) in the first link (Link1). For example, the AP multi-link device can transmit an ACK associated with a frame corresponding to the second TID (TID 1) in the second link (Link2), and can transmit an ACK associated with a frame corresponding to the third TID (TID 2) in the second link (Link2). In these embodiments, the multi-link device transmits a response to a frame in the link in which the frame is received, and thus the complexity of implementation can be low.

[0184] According to another detailed embodiment, the multi-link device can transmit a response to a corresponding frame in the link to which the corresponding TID is mapped, as opposed to the link in which a frame corresponding to a TID that is not mapped to the link is transmitted. In this instance, the response to the corresponding frame can be an ACK. For example, Figure 16 The AP multi-link device in embodiments of the present disclosure can transmit an ACK associated with a frame corresponding to the first TID (TID 0) in the first link (Link1) and an ACK associated with a frame corresponding to the third TID (TID 2). In addition, the AP multi-link device can transmit an ACK associated with a frame corresponding to the second TID (TID 1) in the second link (Link2). In these embodiments, the multi-link device can transmit a response to a frame corresponding to a TID via a link to which the TID is not mapped, and thus the processing burden of collecting responses transmitted in multiple links can be reduced.

[0185] An exception to performing a transmission regardless of the mapping between a link and a TID has been described with reference to Figure 16 An exception to performing a transmission regardless of the mapping between a link and a TID is described again with reference to Figure 17 and Figure 18 , according to other detailed embodiments.

[0186] Figure 17 is a diagram illustrating an operation of a station performing UL MU transmission according to an embodiment of the present disclosure. Figure 18 is a diagram illustrating a multi-link device performing multi-TID aggregation according to an embodiment of the present disclosure.

[0187] As described above, in case that the restriction on the transmission end time is applied, the multi-link device can compare the priority corresponding to the TID not mapped to the link and the priority corresponding to the TID mapped to the link. In this instance, the multi-link device can determine whether to transmit the MPDU corresponding to the TID not mapped to the link in the corresponding link based on the comparison result. Specifically, in case that the priority of the MPDU corresponding to the TID mapped to the link is higher than the priority of the MPDU corresponding to the TID not mapped to the link, the multi-link device can transmit the MPDU corresponding to the TID not mapped to the link in the corresponding link. For example, in case that the priority of the MPDU corresponding to the TID not mapped to the link has the highest priority, the multi-link device can transmit the MPDU corresponding to the TID not mapped to the link in the corresponding link.

[0188] According to another detailed embodiment, in case that the priority of the MPDU corresponding to the TID not mapped to the link is lower than the priority of the MPDU corresponding to the TID mapped to the link, the multi-link device can transmit the MPDU corresponding to the TID not mapped to the link in the corresponding link. For example, in case that the priority of the MPDU corresponding to the TID not mapped to the link has the lowest priority, the multi-link device can transmit the MPDU corresponding to the TID not mapped to the link in the corresponding link. Through the above, the multi-link device can have an opportunity to transmit traffic having a low priority and having a little opportunity for transmission.

[0189] The situation in which the multi-link device can transmit the MPDU corresponding to the TID not mapped to the link in the corresponding link can be allowed only when the MPDU corresponding to the TID mapped to the link and the MPDU corresponding to the TID not mapped to the link are transmitted together. Specifically, the transmission of the MPDU corresponding to the TID mapped to the link and the MPDU corresponding to the TID not mapped to the link together can be performed as follows. An aggregated MPDU (A-MPDU) transmitted in any one link can be an aggregation of the MPDU corresponding to the TID mapped to the corresponding link and the MPDU corresponding to the TID not mapped to the corresponding link. In addition, a PPDU transmitted in any one link can include the MPDU corresponding to the TID mapped to the corresponding link and the MPDU corresponding to the TID not mapped to the corresponding link.

[0190] These embodiments can be applied to the UL MU transmission operation. First, the UL MU transmission operation will be described with reference to FIG. 10. Figure 17 The UL MU transmission operation will be described.

[0191] Multiple stations can transmit PPDUs simultaneously. Such a transmission or series of procedures for the transmission is referred to as uplink (UL) multi-user (MU) operation or UL MU transmission. For the UL MU transmission, an operation of triggering the transmission of the multiple stations can be performed in advance.

[0192] In addition, in a case where the multiple stations transmit a single PPDU simultaneously, the multiple stations can use a trigger-based (TB) PPDU. The TB PPDU can include the HE TB PPDU and the EHT TB PPDU, which have been described in advance. In addition, the TB PPDU can be a PPDU supporting simultaneous transmission by the multiple stations. The multiple stations can receive a frame triggering the UL MU transmission, and can perform the UL MU transmission based on the received frame. The AP can transmit the frame triggering the UL MU transmission to the multiple stations. In addition, the frame triggering the UL MU transmission can indicate a resource unit (RU) in which the UL MU transmission is to be performed and is allocated to each of the multiple stations in the performed UL MU transmission. The station can transmit the TB PPDU via the RU allocated to the station. In addition, the frame triggering the UL MU transmission can be a trigger frame or a frame including trigger information. The frame including the trigger information can include the trigger information in a MAC header. Specifically, the frame including the trigger information can include the trigger information in an A-control field. Specifically, the trigger information can be a trigger response scheduling (TRS) control field. In addition, the UL MU transmission can be transmitted via the above-described TB PPDU. In addition, the multiple stations can perform the UL MU transmission as an immediate response. That is, an interval between a PPDU including the frame triggering the UL MU transmission and a PPDU including the UL MU transmission can be SIFS.

[0193] The frame triggering the UL MU transmission can include information associated with a length of the PPDU including the UL MU transmission. For ease of description, the information associated with the length of the PPDU including the UL MU transmission can be referred to as response length information. The response length information can be the length of the PPDU including the UL MU transmission. Based on the response length information included in the frame triggering the UL MU transmission, the station can determine the length of the PPDU including the UL MU transmission. Specifically, the response length information can indicate a value of a length field of an L-SIG field of the PPDU including the UL MU transmission. For example, based on the length field of the triggering frame, the station can determine the value of the length field of the L-SIG field of the TB PPDU. In addition, although the station does not have enough traffic to generate the PPDU corresponding to the response length information, the station can determine the length of the TB PPDU according to the response length information. Specifically, the station can insert padding to the TB PPDU. For example, in a case that the station has empty bits of the TB PPDU even after inserting all the traffic of the buffer to the TB PPDU, the station can insert the padding to the empty bits. With the above, the station can satisfy the length of the TB PPDU indicated by the response length information. In addition, the response length information can indicate a number of OFMD symbols included in the TB PPDU. Accordingly, when the station performs the UL MU transmission, the station can perform the transmission according to the length indicated by the frame triggering the UL MU transmission. Further, all the stations performing the UL MU transmission can transmit the TB PPDUs having the same length. In addition, the response to the UL MU transmission can be an immediate response to the UL MU transmission. Accordingly, the interval between the UL MU transmission and the response to the UL MU transmission can be SIFS.

[0194] REFERENCE Figure 17, the AP transmits a trigger frame to the first station (STA 1) and the second station (STA 2). Each of the first station (STA 1) and the second station (STA 2) can transmit a TB PPDU via an RU, where the allocation to each of the first station (STA 1) and the second station (STA 2) is indicated by the trigger frame. In this example, the length of the TB PPDU transmitted by each of the first station (STA 1) and the second station (STA 2) can be determined based on the response length information indicated by the trigger frame. The length of the TB PPDUs transmitted by the first station (STA 1) and the second station (STA 2) is equal. In addition, the first station (STA 1) and the second station (STA 2) can transmit the TB PPDUs as an immediate response to the trigger frame. The AP can transmit an ACK associated with the frames included in the TB PPDUs transmitted by each of the first station (STA 1) and the second station (STA 2). As described above, the limitation on the end of transmission time can be applied even in the case where the stations transmit the TB PPDUs. In this example, the embodiments regarding the exception embodiments associated with the mapping between the links and the TIDs can be applied. This will be described with reference to Figure 18 in further detail.

[0195] In the case where the stations perform the UL MU transmission, the stations can transmit the frames corresponding to the TIDs which are not mapped to the link in which the UL MU transmission is performed. Specifically, in the case where the stations perform the UL MU transmission, the stations can transmit the frames mapped to the link in which the UL MU transmission is performed and the frames corresponding to the TIDs which are not mapped to the corresponding link together. In this example, the length of the TB PPDU transmitted by each of the stations can be determined based on the response length information indicated by the trigger frame. The length of the TB PPDUs transmitted by the stations is equal. In addition, the stations can transmit the TB PPDUs as an immediate response to the trigger frame. The AP can transmit an ACK associated with the frames included in the TB PPDUs transmitted by each of the stations. As described above, the limitation on the end of transmission time can be applied even in the case where the stations transmit the TB PPDUs. In this example, the embodiments regarding the exception embodiments associated with the mapping between the links and the TIDs can be applied. This will be described with reference to Figure 18 In this example, the uplink of the first link (Link 1) can be mapped to AC_VI and AC_BE. In this example, as described above with reference to Figure 18 (b), the stations can transmit a TB PPDU including a PDSU or a data frame corresponding to AC_VI and AC_BE and padding. In this example, in these embodiments, in the case where the length of the padding is significantly long, the transmission efficiency can be deteriorated. In addition, the station (e.g., the AP) which transmits the trigger frame cannot accurately identify the traffic stored in the buffer of each of the stations which perform the UL MU transmission, and thus, the length of the padding included in the TB PPDU has an increased possibility. Accordingly, the stations can additionally include another AC which is not mapped to the first link (Link 1), i.e., a PDSU or a data frame corresponding to AC_VO, in the TB PPDU, as shown in Figure 18 (c).

[0196] As described above, the priority of the TIDs mapped to the station link and the priority of the TIDs not mapped to the link can be compared, and based on the comparison result, it can be determined whether to transmit frames corresponding to the TIDs not mapped to the link in the corresponding link. For example, in Figure 18 In (c), AC_VO can have a higher priority than the priority of AC_VI or AC_BE as an AC mapped to the first link (Link1). Also, the station as described above can not transmit a PPDU including only frames corresponding to the TIDs not mapped to the link, but can transmit frames corresponding to the TIDs mapped to the link and frames corresponding to the TIDs not mapped to the link together. Although Figure 18 Embodiments of the disclosure are illustrated with reference to AC, but the above-described embodiments can also be applied to a case in which TIDs or TSIDs, not AC, are mapped to a link.

[0197] Also, the above-described embodiments can be applied together with a multi-TID aggregation rule. The multi-TID aggregation rule can determine a rule in which MPDUs corresponding to different TIDs should be aggregated in a single A-MPDU. Thus, MPDUs aggregated according to the multi-TID aggregation rule can not follow the mapping between the link and the TID. Specifically, in the case in which the station aggregates MPDUs according to the multi-TID aggregation rule, the station can transmit MPDUs corresponding to TIDs not mapped to the link in the corresponding link. The multi-TID aggregation rule can be as follows.

[0198] 1) The TXOP limit of the transmission sequence according to which multi-TID aggregation is performed is greater than or equal to 0.

[0199] 2) At least one of frames or MPDUs of a primary AC or an AC for obtaining a TXOP is included in the aggregated A-MPDU.

[0200] 3) The TIDs corresponding to the frames or MPDUs aggregated in the A-MPDU are the primary AC or TIDs having a higher priority than the primary AC.

[0201] 4) The length of the A-MPDU does not exceed the TXOP obtained by the primary AC.

[0202] 5) The number of TIDs of the frames or MPDUs aggregated in the A-MPDU does not exceed the number of TIDs indicated by the multi-TID aggregation Rx support.

[0203] In another detailed embodiment, condition 3) for the described multi-TID aggregation rule can be replaced with the following condition 3-1).

[0204] 3) The TIDs corresponding to the frames or MPDUs aggregated in the A-MPDU are the primary AC or TIDs having a lower priority than the primary AC.

[0205] In another detailed embodiment, the station can transmit a frame corresponding to a TID not mapped to the link in the corresponding link based on the PPDU format. Specifically, in case the station transmits a DL MU PPDU, the station can transmit a frame corresponding to a TID not mapped to the link in the corresponding link. In this instance, the DL MU PPDU can be a DL HE MU PPDU or an EHT PPDU transmitted to a plurality of users. In addition, the station can transmit any frame corresponding to any TID not mapped to the link in the corresponding link.

[0206] Specifically, in case the station transmits a TB PPDU, the station can transmit a frame corresponding to a TID not mapped to the link in the corresponding link. In this instance, the TB PPDU can be a HE TB PPDU or an EHT TB PPDU. In a detailed embodiment, in case the preferred AC subfield of the trigger frame indicates a predetermined AC and even a TID not mapped to the link has a priority higher than or equal to the priority of the predetermined AC, the station can transmit a frame corresponding to the corresponding TID using the TB PPDU. In another detailed embodiment, in case the preferred AC subfield of the trigger frame indicates a predetermined AC and even a TID not mapped to the link has a priority lower than the priority of the predetermined AC, the station can transmit a frame corresponding to the corresponding TID using the TB PPDU. A case in which the present embodiment is applied can be a case in which there is no frame corresponding to a priority higher than the priority of the predetermined AC in the transmission buffer. In addition, as described above, the station can transmit a frame corresponding to a TID using the TB PPDU, although the TID is not mapped to the link, within a range allowing the length of the TB PPDU. In this instance, the number of TIDs of frames aggregated in the A-MPDU can be limited. Specifically, a TID aggregation limit subfield included in the trigger frame can indicate the maximum number of TIDs aggregated in the A-MPDU.

[0207] Figure 19 FIG. 1 is a diagram illustrating an element for signaling information associated with mapping between a link and a TID according to an embodiment of the disclosure.

[0208] The station can perform whether to support or allow the mapping between the link and the TID, which has been described with reference to FIGS. 1 to 5, based on the PPDU format. Figure 16 to Figure 18Signaling associated with the described embodiments. In addition to the TIDs mapped to the link, receiving a frame corresponding to a TID can require the station to perform additional operations. Specifically, where a limit on the end of transmission time is applied, the station can perform signaling associated with whether or not frame transmissions that do not follow the mapping between the link and the TID are supported or allowed. Where the information indicating whether or not frame transmissions that do not follow the mapping between the link and the TID are supported or allowed indicates a first predetermined value, the corresponding information can indicate that the station supports or allows frame transmissions that do not follow the mapping between the link and the TID. Specifically, where the information indicating whether or not frame transmissions that do not follow the mapping between the link and the TID are supported or allowed indicates a first predetermined value, the corresponding information can indicate that the station supports or allows frame transmissions that do not follow the mapping between the link and the TID if a limit on the end of transmission time is applied.

[0209] Where the information indicating whether or not frame transmissions that do not follow the mapping between the link and the TID are supported or allowed indicates a second predetermined value, the corresponding information can indicate that the station does not support or allow frame transmissions that do not follow the mapping between the link and the TID. Specifically, where the information indicating whether or not frame transmissions that do not follow the mapping between the link and the TID are supported or allowed indicates a second predetermined value, the corresponding information can indicate that the station does not support or allow frame transmissions that do not follow the mapping between the link and the TID if a limit on the end of transmission time is applied.

[0210] Additionally, the information indicating whether or not frame transmissions that do not follow the mapping between the link and the TID are supported or allowed can indicate whether or not the station supports or allows transmissions according to a limit on the end of transmission time. In this instance, allowing indicates whether or not the corresponding transmissions can be received.

[0211] Additionally, the station can perform signaling of the maximum number of TIDs that the station is able to aggregate in a single A-MPDU. In this instance, the maximum number of TIDs that a single A-MPDU is able to aggregate can be greater than or equal to the maximum number indicated by the TID aggregation limit field of the trigger frame. Specifically, the station can perform signaling of the maximum number of TIDs that the station is able to aggregate in addition to the TIDs mapped to the link. In another detailed embodiment, the station can perform signaling of the maximum number of TIDs that the station is able to aggregate, including the TIDs mapped to the link. In the above embodiments, the signaling can be of the maximum number of TIDs that the station is able to aggregate if a limit on the end of transmission time is applied. Additionally, the station can perform signaling of the maximum number of TIDs that the station is able to receive.

[0212] In the above embodiments, a capability element or an operation element can be used for signaling. The station can use the capability element or the operation element to perform signaling about whether the station supports or allows frame transmissions that do not follow the mapping between links and TIDs. In addition, the station can use the capability element or the operation element to perform signaling of the maximum number of TIDs that the station can aggregate. The capability element can include an EHT capability element. The operation element can include an EHT operation element.

[0213] Figure 19 (a) illustrates a capability element according to an embodiment of the disclosure, and Figure 19 (b) illustrates an operation element according to another embodiment of the disclosure. A multi-link multi-TID aggregation support subfield of the capability element can perform signaling to an AP about whether a non-AP station supports frame transmissions that do not follow the mapping between links and TIDs. A TID number subfield of the capability element indicates the maximum number of TIDs that the station can aggregate. A multi-link multi-TID aggregation permission subfield of the operation element can indicate to the non-AP station whether the AP allows frame transmissions that do not follow the mapping between links and TIDs. In addition, the TID number subfield of the capability element indicates the maximum number of TIDs that the AP can receive.

[0214] The support-related signaling and the permission-related signaling can be included in the same type of element. In addition, the signaling indicating whether frame transmissions that do not follow the mapping between links and TIDs are supported and the signaling indicating whether frame transmissions that do not follow the mapping between links and TIDs are allowed can be included in the same type of subfield of the same type of element. In this instance, the information indicating the subfield of the element can differ according to the role of the station that transmits the element. Specifically, depending on whether the element is transmitted by a non-AP station or by an AP, the information indicating the subfield of the element can differ. For example, in the case where the respective element is transmitted by a non-AP station, the subfield of the respective element can indicate whether frame transmissions that do not follow the mapping between links and TIDs are supported. In addition, in the case where the respective element is transmitted by an AP, the subfield of the respective element can indicate whether frame transmissions that do not follow the mapping between links and TIDs are allowed.

[0215] In case that the restriction on the transmission end time is applied, it can be determined for each PPDU format whether the frame transmission not following the mapping between the link and the TID is allowed. In case that the information indicating whether the frame transmission not following the mapping between the link and the TID is allowed is included in the frame or the PPDU, the corresponding information can be applied to the response to the corresponding frame or PPDU. In case that the information indicating whether the frame transmission not following the mapping between the link and the TID is allowed is included in the frame or the PPDU, the corresponding information can be applied in a TXOP including the corresponding frame or PPDU. The maximum number of TIDs that a station can aggregate can be determined for each PPDU format. In case that the information indicating the maximum number of TIDs that a station can aggregate is included in the frame or the PPDU, the corresponding information can be applied to the response to the corresponding frame or PPDU. In case that the information indicating the maximum number of TIDs that a station can aggregate is included in the frame or the PPDU, the corresponding information can be applied to the response to the corresponding frame or PPDU. In case that the information indicating the maximum number of TIDs that a station can aggregate is included in the frame or the PPDU, the corresponding information can be applied in a TXOP including the corresponding frame or PPDU.

[0216] In particular, the frame triggering the UL MU transmission can include information indicating whether the frame transmission not following the mapping between the link and the TID is allowed. In case that the station transmits the response to the frame triggering the UL MU transmission, the station can determine whether to transmit the frame corresponding to the TID not mapped to the link based on the information indicating whether the frame transmission not following the mapping between the link and the TID is allowed. In a detailed embodiment, the information indicating whether the frame transmission not following the mapping between the link and the TID is allowed can be included in a common information field of the triggering frame. For example, the information indicating whether the frame transmission not following the mapping between the link and the TID is allowed can be included in the 64th bit (i.e., B63) of the common information field.

[0217] In another detailed embodiment, information indicating whether transmission of a frame not following the mapping between a link and a TID is allowed can be included in the subsequent bits of the reserved subfield of the UL HE-SIG-A2. In another detailed embodiment, information indicating whether transmission of a frame not following the mapping between a link and a TID is allowed can be included in the bits preceding the trigger-related common information field. In another detailed embodiment, information indicating whether transmission of a frame not following the mapping between a link and a TID is allowed can be included in the user information field of the trigger frame. In addition, the embodiments applied to the information indicating whether transmission of a frame not following the mapping between a link and a TID is allowed can also be applied to the information indicating the maximum number of TIDs that a station is capable of aggregating. The aforementioned common information field can include information commonly applied to the TB PPDU or all stations responding to the trigger frame. The user information field can include information applied to the transmitted TB PPDU or the station providing a response in the RU indicated by the user information field.

[0218] Figure 21 is a diagram illustrating a station performing channel access in order to transmit a trigger frame according to an embodiment of the disclosure.

[0219] In the case of transmission of a frame triggering UL MU transmission, the station can perform channel access that has been described with reference to Figure 6 In this instance, the AIFS can be determined based on the AC, TID, or priority of traffic to be transmitted by the station. Specifically, the AIFS can be a value obtained by adding SIFS to the product of AIFSN and slot time. In the case where the station desires to transmit traffic having a relatively high priority, the length of the AIFS can be relatively short. In addition, in the case where the station desires to transmit traffic having a relatively low priority, the length of the AIFS can be relatively long. In the case where the station performs channel access in order to transmit a trigger frame, how to determine the AC, TID, or priority to be applied by the station can be important.

[0220] In a case where the station performs channel access to transmit the trigger frame, the station can perform channel access based on an AC, a TID, or a priority corresponding to a frame transmitted in response to the trigger frame and a mapping between a link and a TID. Specifically, in a case where the station performs channel access to transmit the trigger frame, the station can perform channel access based on an AC corresponding to a frame transmitted in response to the trigger frame and a mapping between a link and a TID. In this instance, the mapping between the link and the TID can be configured between a transmitter of the trigger frame and a receiver of the trigger frame. In a detailed embodiment, the mapping between the link and the TID can be a mapping between a TID and a link in a direction from the receiver of the trigger frame to the transmitter of the trigger frame. In a case where the station performs channel access in order to transmit the trigger frame, the station can apply an AC or a TID defined in the mapping between the TID and the link in the direction from the receiver of the trigger frame to the transmitter of the trigger frame. In a case where the station performs channel access in order to transmit the trigger frame, the station can not apply an AC or a TID not defined in the mapping between the TID and the link in the direction from the receiver of the trigger frame to the transmitter of the trigger frame. In a case where the station performs channel access in order to transmit the trigger frame, the station can apply a TID or an AC determined based on a TID or an AC defined in the mapping between the TID and the link in the direction from the receiver of the trigger frame to the transmitter of the trigger frame. In addition, if a plurality of receivers receive the trigger frame, the mapping between the link and the TID can be a mapping between a TID and a link in a direction from the plurality of receivers to the transmitter. These embodiments can be applied in a case where the PPDU including only the frame triggering the UL MU transmission includes only the frame triggering the UL MU transmission. In addition, these embodiments can be applied only in a case where the PPDU including the frame triggering the UL MU transmission does not include the QoS data frame.

[0221] In addition, the above-described embodiments can be applied to a case where each receiver of the PPDU including the frame triggering the UL MU transmission is a multi-link device. Accordingly, the above-described embodiments can be applied to a case where each receiver of the PPDU including the trigger frame is a station included in the multi-link device. In a case where the receiver of the PPDU including the trigger frame is a station not included in the multi-link device, the station can use any AC.

[0222] In addition, in a case where the frame triggering the UL MU transmission does not specify a station and triggers random access, the station can perform channel access regardless of the mapping between the link and the TID.

[0223] In Figure 20In the middle, the AP multi-link device includes a first AP (AP 1). In addition, the first non-AP multi-link device (non-AP MLD 1) includes a first station (STA 1). In addition, the second non-AP multi-link device (non-AP MLD 2) includes a second station (STA 2). A first link (Link1) is configured between the first station (STA 1) and the first AP (AP 1). The first link (Link1) is configured between the second station (STA 2) and the first AP (AP 1). A mapping between links and TIDs in the first link (Link1) is configured. AC_VI and AC_VO are mapped to the link from the first station (STA 1) to the first AP (AP 1). In addition, all TIDs are mapped to the link from the first AP (AP 1) to the first station (STA 1). A mapping between links and TIDs in the second link (Link2) is configured. AC_VO is mapped to the link from the second station (STA 2) to the first AP (AP 1). In addition, all TIDs are mapped to the link from the second AP (AP 2) to the first station (STA 1). In Figure 20 In (b), in a case where the first AP (AP 1) transmits a trigger frame to the first station (STA 1) and the second station (STA 2), the first AP (AP 1) can perform channel access based on AC_VI and AC_VO. This is because AC_VI and AC_VO are mapped to the link from the first station (STA 1) to the first AP (AP 1), and AC_VO is mapped to the link from the second station (STA 2) to the first AP (AP 1). In a case where the first AP (AP 1) transmits a trigger frame to the first station (STA 1) and a third station (STA 3) that do not belong to any multi-link device, the first AP (AP 1) can perform channel access using any AC. In a case where the first AP (AP 1) transmits a trigger frame that triggers random access, the first AP (AP 1) can perform channel access using any AC.

[0224] According to another detailed embodiment, in a case where a station performs channel access to transmit a frame that triggers UL MU transmission, the station can perform channel access regardless of a mapping between links and TIDs. In this example, the station can use any AC. In this example, the mapping between links and TIDs can be a mapping between UL links and TIDs. In addition, the mapping between links and TIDs can be a mapping between TIDs and links in a direction in which the trigger frame is transmitted.

[0225] As described above, when a station sends a TB PPDU, it can send frames corresponding to the TIDs of links not mapped to the corresponding links. If a station does not acquire a TXOP through a contention process, it can perform a transmission regardless of the mapping between links and TIDs. If a station acquires a TXOP through a contention process, it can perform a transmission based on the mapping between links and TIDs. For example, if a station does not acquire a TXOP through a contention process, it can send frames corresponding to the TIDs of links not mapped to the corresponding links. If a station acquires a TXOP through a contention process, it can send only frames corresponding to the TIDs of links mapped to the corresponding links.

[0226] Figure 21 This is a diagram illustrating the operation of a multi-link device performing transmission across multiple links according to an embodiment of the present disclosure.

[0227] For reference Figure 10 to Figure 15 In the described embodiments, limitations on the transmission end time of multi-link transmissions can be applied. In detailed embodiments, the multi-link device can determine whether to apply limitations on the transmission end time based on the frequency intervals between the links. The degree of internal leakage may vary depending on the frequency interval. When the frequency intervals between the links fall within a predetermined frequency interval, the multi-link device can be limited to performing simultaneous transmission and reception on multiple links. Furthermore, when the frequency intervals between the links are greater than the predetermined frequency interval, the multi-link device is not limited to performing simultaneous transmission or simultaneous reception on multiple links.

[0228] Additionally, bandwidth restrictions can be applied to multi-link devices that perform restrictive STR execution or communicate with other multi-link devices that perform restrictive STR execution. Furthermore, under predetermined conditions, multi-link devices that perform restrictive STR execution or communicate with other multi-link devices that perform restrictive STR execution can use bandwidth narrower than a predetermined width.

[0229] exist Figure 21 In a multi-link system, a non-AP device can include a first station (STA1) and a second station (STA2). The first station (STA1) and the second station (STA2) can operate in the first link (Link1) and the second link (Link2), respectively. Non-AP multi-link devices can restrict STR (Signal Streaming) support. Specifically, the STR support of a non-AP multi-link device can be limited based on the link's bandwidth or channel location. Figure 21In a detailed embodiment, in a case where the non-AP multi-link device operates in the channel P20 of the first link (Link1) and the channels of the second link, the non-AP multi-link device can perform STR. In addition, in a case where the non-AP multi-link device operates in the channel S20 or the channel S40 of the first link (Link1) and the channels of the second link, the non-AP multi-link device cannot perform STR.

[0230] As described above, a station performing a transmission associated with a non-AP multi-link can transmit a PPDU using limited bandwidth. Specifically, as described above, a station performing a transmission associated with a non-AP multi-link can transmit a PPDU using limited bandwidth when the non-AP multi-link device performs a transmission. In Figure 21 In an embodiment, in a case where the second station (STA 2) is performing a transmission, the first AP (AP 1) can perform a transmission to the second station (STA 2) using a channel other than the channel S20 or the channel S40, which is a channel that the first station (STA 1) is restricted to use in the first link (Link1).

[0231] A multi-link device can autonomously make a decision associated with the use of the above-described restricted channel. In another detailed embodiment, the use of the restricted channel can be specifically indicated. For example, a frame triggering a UL MU transmission can allocate a restricted channel. In addition, the multi-link device can perform signaling of whether STR is available for each channel when a corresponding channel is used. For example, when each of the channel P20, the channel P40, and the channel P80 is used, the multi-link device can perform signaling of whether STR is available for each channel.

[0232] Figure 22 FIG. 1 is a diagram illustrating an operation of setting a NAV by a multi-link device according to an embodiment of the disclosure.

[0233] As described above, a transmission can fail due to internal leakage caused when transmission and reception are simultaneously performed in a plurality of adjacent links. In Figure 22In this case, the multi-link device also performs transmission in the second link while performing reception via the first link. Due to the transmission in the second link, the multi-link device can fail in reception in the first link. A station operating in the second link can access the channel and can perform transmission in case the station determines that the channel of the second link is idle. A station operating in the first link (Linkl) can set a network allocation vector (NAV) based on a PPDU or a frame transmitted in the first link (Linkl). The station operating in the first link (Linkl) can determine that the channel is busy due to the NAV when another station performs transmission in the first link (Linkl). As described above, in case a frame or a PPDU transmitted in the first link can set a NAV in the second link, the probability of transmission failure due to internal leakage can be reduced. This will be described with reference to Figure 23 to Figure 25

[0234] Figure 23 is a diagram illustrating an operation of setting a NAV by a multi-link device according to an embodiment of the disclosure.

[0235] The multi-link device can share duration information between the links. In this instance, the duration information can be a TXOP duration field of a signaling field of a PPDU. In this instance, the signaling field can be a HE-SIG-A field. Further, the signaling field can be a U-SIG field. In addition, the duration information can be a value indicated by a duration / ID field of a MAC header. The TXOP duration field and the duration / ID field can indicate a TXOP. In another detailed embodiment, the duration information can be a value indicated by a length field of an L-SIG field of a PPDU. The length field can indicate a length from an end of the L-SIG field to an end of the PPDU in the PPDU including the L-SIG field.

[0236] Based on the shared duration information, the multi-link device can limit channel access or transmission in each link. Specifically, based on the shared duration information, the multi-link device can set a NAV of a station of each link. For example, based on a frame or a PPDU transmitted to another station included in the multi-link device, a station included in the multi-link device can set the NAV. In this instance, in case the multi-link device performs channel access or transmission, the multi-link device can reset the NAV. In this instance, the NAV can be an intra-BSS NAV. The intra-BSS NAV can be a NAV set by an intra-BSS frame or an intra-BSS PPDU.

[0237] In Figure 23 ​In an embodiment, a multi-link device can perform reception in a first link. Duration information received in the first link can be communicated to a second link, and a station operating in the second link can set a NAV based on the communicated duration information. As described above, the NAV is also set for the station operating in the second link, and thus, the station operating in the second link does not perform channel access or transmission when a transmission is performed in the first link.

[0238] In another detailed embodiment, a plurality of stations included in a multi-link device can use an inter-link NAV. Specifically, a station included in the multi-link device can perform channel access based on an inter-link NAV, which is a NAV set based on a PPDU or frame exchanged by another station included in the same multi-link device. For example, in a case where the multi-link device operates in a first link and a second link, a station among stations of the multi-link device operating in the second link can set an inter-link NAV based on a PPDU or frame transmitted in the first link. In this instance, the corresponding station can not perform transmission in the second link based on a value of the set inter-link NAV. Specifically, based on the value of the set inter-link NAV, the corresponding station can determine that the channel in the second link is busy. In addition, a multi-link device not supporting STR can access the channel based on the inter-link NAV. In this instance, the multi-link device setting the inter-link NAV can determine whether to perform channel access or transmission in the multi-link device or in all links in which the multi-link device operates based on the inter-link NAV.

[0239] In addition, a station can access the channel based on a basic NAV as well as an intra-BSS NAV. The basic NAV can be a NAV set by an inter-BSS frame or an inter-BSS PPDU. In addition, in a case where the station cannot determine whether a received frame is an inter-BSS frame or an intra-BSS frame, or in a case where the station cannot determine whether a received PPDU is an inter-BSS PPDU or an intra-BSS PPDU, the station can set the basic NAV based on the received frame or PPDU.

[0240] In the case where the inter-link NAV is set as described above, although the NAV set in association with the transmission in another link is reset, the NAV value set in association with the transmission in the link can be maintained as it is. For example, in the case where a multi-link device operates in a first link and a second link, a station of the multi-link device operating in the second link among the stations of the multi-link device can set the NAV based on a PPDU or a frame transmitted in the second link. Subsequently, in the case where the TXOP expires in the first link and the NAV is reset after the corresponding station sets the NAV based on a PPDU or a frame transmitted in the first link, the NAV set for the transmission in the second link can also be reset. In the case of the inter-link NAV operation, although the TXOP expires in the first link and the inter-link NAV is reset, the multi-link device can maintain the NAV set for the transmission in the second link. Accordingly, the multi-link device can reliably operate using the inter-link NAV.

[0241] In the above-described embodiments, the operation of the station setting the NAV can be replaced with the operation of the station suspending channel access or transmission in the physical layer. Alternatively, in the above-described embodiments, the operation of the station setting the NAV can be replaced with the operation of the station determining that the channel is busy. In this instance, the operation of the station resetting the NAV can be replaced with the operation of the station performing channel access, performing transmission, or determining that the channel is idle. To this end, a primitive exchanged between the physical layer and the MAC layer can be used. Specifically, a primitive connecting the MAC layer of a single station of a multi-link device and the physical layer of another station of the corresponding multi-link device can be used. Alternatively, the MAC layer of a single station of a multi-link device and the MAC layer of another station of the corresponding multi-link device can be connected.

[0242] In addition, in the case where a single station of a multi-link device starts receiving a PPDU, another station of the multi-link device can suspend performing channel access. As described above, the other station can suspend performing channel access based on the duration information. However, due to the location of the field including the duration information, the suspension of performing channel access can be delayed. Accordingly, since channel access is performed until the duration information is obtained, internal leakage can occur when transmission is performed. Accordingly, as described above, in the case where a single station of a multi-link device starts receiving a PPDU, another station of the multi-link device can suspend performing channel access. In addition, in the case where the intended receiver of the PPDU received by any one station or the frame included in the PPDU is not the corresponding station, the other station can resume the suspended channel access. This will be described in detail with reference to Figure 24 In detail.

[0243] Figure 24 is a diagram illustrating a station of a multi-link device suspending performing channel access or transmission and resuming performing channel access or transmission due to another station of the multi-link device receiving a PPDU according to an embodiment of the disclosure.

[0244] As described above, a station of a multi-link device can suspend channel access or transmission due to another station of the multi-link device receiving a PPDU. In this instance, the station can resume channel access or transmission in a case where the receiver of the PPDU or the frame included in the PPDU received by the other station is different from the other station. Specifically, the station can resume channel access or transmission in a case where the other station fails to perform PPDU decoding. In a detailed embodiment, the station can continuously suspend channel access or transmission in a case where the other station obtains duration information from the L-SIG field of the PPDU. In a case where the station does not obtain duration information from the L-SIG field of the PPDU, the station can resume channel access or transmission. For example, in a case where the station fails to decode the L-SIG field of the PPDU, the station can resume channel access or transmission. Also, in a case where the other station fails to decode the U-SIG field or the HE-SIG-A field of the PPDU, the station can resume channel access or transmission. In a detailed embodiment, the station can continuously suspend channel access or transmission in a case where the other station obtains duration information from the U-SIG field or the HE-SIG-A field of the PPDU. Also, in a case where the PHY identifier of the PPDU received by the other station is a PPDU format that is not supported by the other station, the station can resume channel access or transmission.

[0245] Also, in a case where the BSS color of the PPDU received by the other station does not indicate the BSS to which the other station belongs, the station can resume channel access or transmission. In a case where the BSS color of the PPDU received by the other station indicates the BSS to which the other station belongs, the station can continuously suspend channel access or transmission. In a case where the station fails to obtain the BSS color from the U-SIG field or the HE-SIG-A field of the PPDU, the station can resume channel access or transmission.

[0246] Also, in a case where the intended receiver of the PPDU received by the other station is not the other station, the station can resume channel access or transmission. In a case where the intended receiver of the PPDU received by the other station is the other station, the station can continuously suspend channel access or transmission. In a case where the other station is the intended receiver of the received PPDU, at least one STA-ID included in the EHT-SIG or the HE-SIG-B of the PPDU can indicate the other station. Specifically, in a case where the other station is the intended receiver of the received PPDU, one of the STA-IDs included in the EHT-SIG or the HE-SIG-B of the PPDU can indicate a group including the other station. For example, in a case where one of the STA-IDs indicates a broadcast, the station can determine that the other station is the intended receiver of the received PPDU.

[0247] Additionally, if the intended receiver of a PPDU received by another station is not that other station, the station can restore channel access or transmission. In this example, if the station indicated by the RA or DA field in the MAC header is another station, the station can determine that the intended receiver of frames included in a PPDU received by that other station is that other station. If the RA or DA field in the MAC header indicates a group including another station, the station can determine that the intended receiver of frames included in a PPDU received by that other station is that other station. If the RA or DA field in the MAC header indicates a broadcast, the station can determine that the intended receiver of frames included in a PPDU received by that other station is that other station.

[0248] If the intended receiver of a frame included in a PPDU received at another station is another station, the station can continuously suspend channel access or transmission.

[0249] In the above embodiments, if a station continuously suspends channel access or transmission, it can suspend channel access or transmission until the end of the PPDU received by another station. In this embodiment, the station can quickly resume transmission. In another detailed embodiment, if a station continuously suspends channel access or transmission, it can suspend channel access or transmission until the TXOP duration. In this embodiment, the station more reliably protects the frame exchange sequence performed in another link. In this example, the TXOP duration can be obtained from the duration / ID field of the MAC header or the signaling field of the PPDU.

[0250] When another station receives a PPDU and sequentially decodes the signaling fields of the received PPDU, the aforementioned suspension / resumption of channel access or transmission can be applied. In this example, the decoding sequence can be determined based on the PPDU format and frame format. For example, if the received PPDU is as follows... Figure 24 In the case of the EHT PPDU shown, another station can sequentially decode the L-SIG, U-SIG, EHT-SIG, and MAC headers. Additionally, in the case of a HE SU PPDU or HE TB PPDU, another station can sequentially decode the L-SIG, HE-SIG-A, and MAC headers. Furthermore, in the case of a HE MUPPDU, another station can sequentially decode the L-SIG, HE-SIG-A, HE-SIG-B, and MAC headers. Finally, in the case of an 11a / g PPDU, another station can sequentially decode the L-SIG and MAC headers.

[0251] The intended receiver of the PPDU or frame described above can be the intended receiver of the RU in which the PPDU is transmitted. In addition, the identifier used to determine whether the receiver is the intended receiver can be a value determined based on a station's AID or MAC address. In addition, the identifier used to determine whether the receiver is the intended receiver can be an identifier that indicates a single station.

[0252] Figure 25 is a diagram illustrating a method of transmitting, by a multi-link device, a response to a trigger frame in a case where a NAV is configured for the multi-link device and the trigger frame is received, according to an embodiment of the disclosure.

[0253] In a case where a station transmits a response to a frame triggering UL MU transmission, the station can not consider the intra-BSS NAV and the inter-link NAV described above. Specifically, in a case where a station transmits a response to a frame triggering UL MU transmission and from a BSS to which the station belongs, the station can not consider the intra-BSS NAV and the inter-link NAV described above. In a case where a station transmits a response to a frame triggering UL MU transmission and from a multi-link device including a station to which the station belongs, the station can not consider the intra-BSS NAV and the inter-link NAV described above. In this instance, the station can be an AP.

[0254] In a case where a station receives a trigger frame from a multi-link device including a station that transmits a frame setting the currently set intra-BSS NAV or inter-link NAV and the station transmits a response to the trigger frame, the station can not consider the intra-BSS NAV and the inter-link NAV. In addition, in a case where a station receives a trigger frame from a station that transmits a frame setting the currently set intra-BSS NAV or inter-link NAV and the station transmits a response to the trigger frame, the station can not consider the intra-BSS NAV and the inter-link NAV.

[0255] In the embodiments described above, the fact that the station does not consider the NAV means that the station ignores the NAV, determines virtual carrier sensing to be idle, or determines not to perform virtual carrier sensing, although the NAV is set.

[0256] In these embodiments, although an AP multi-link device sets a NAV for a non-AP multi-link device, the AP multi-link device can trigger a transmission by the non-AP multi-link device. Accordingly, the AP multi-link device can improve the efficiency of the network.

[0257] In Figure 25In an embodiment of the above, the non-AP multi-link device can include a first station (STA1) and a second station (STA2). The first station (STA1) and the second station (STA2) can operate in a first link (Link1) and a second link (Link2), respectively. The second station (STA2) sets a NAV based on a frame or PPDU transmitted to the first station (STA1). In this instance, the second station (STA2) can transmit a response to a trigger frame without considering the NAV set for the second station (STA2) in a case where the second station (STA2) receives the trigger frame triggering the second station (STA2) from an AP associated with the second station (STA2) or an AP included in a multi-link device including the AP associated with the second station (STA2).

[0258] Although the present disclosure is described above using WLAN communication as an example, the present disclosure is not limited thereto and can be equally applied to other communication systems such as cellular communication. In addition, although the method, device, and system of the present disclosure have been described in conjunction with certain embodiments, some or all components, operations of the present disclosure can be implemented using a computer system having a general hardware architecture.

[0259] The features, structures, effects, and the like described in the above-described embodiments are included in at least one embodiment of the present disclosure, and are not necessarily limited to one embodiment. Furthermore, a person of ordinary skill in the art to which the embodiments belong can combine or modify the features, structures, effects, and the like shown in each of the embodiments for other embodiments. Therefore, matters related to these combinations and modifications should be interpreted as falling within the scope of the present disclosure.

[0260] Although the above has focused on the embodiments, this is merely an example and is not limited to the present disclosure, and a person of ordinary skill in the art to which the present disclosure belongs will appreciate that various modifications and applications not exemplified above are possible without departing from the essential characteristics of the present embodiments. For example, each component specifically shown in the embodiments is a component that can be modified and implemented. In addition, differences related to these modifications and applications should be interpreted as falling within the scope of the present disclosure as defined in the appended claims.

Claims

1. An access point (AP) multi-link device using multiple links, the AP multi-link device comprising: transceiver; as well as processor, Specifically, when the AP multi-link device uses the transceiver to simultaneously send multiple PPDUs to non-AP multi-link devices across multiple links, the processor is configured to: align the ends of the multiple PPDUs that request immediate responses, and not align the ends of PPDUs that only include frames not requesting immediate responses with the ends of PPDUs that include frames requesting immediate responses. If the AP multilink device performs a transmission in another link, the reception by the non-AP multilink device in one of the multiple links is limited due to internal leakage from the other link.

2. The AP multi-link device according to claim 1, wherein, When the AP multi-link device transmits multiple PPDUs simultaneously across multiple links, the processor is configured to transmit the multiple PPDUs in such a manner that the end of the PPDUs that include only frames that do not request an immediate response is no later than the end of the PPDUs that include frames that request an immediate response.

3. The AP multi-link device according to claim 1, wherein, The ACK strategy is used to determine whether the frame that requests an immediate response is a frame that requests an ACK.

4. The AP multi-link device according to claim 3, wherein, The frame requesting ACK is a data frame.

5. A non-access point (AP) multi-link device using multiple links, the non-AP multi-link device comprising: transceiver; as well as processor, The processor is configured as follows: This enables the non-AP multi-link device to simultaneously receive multiple PPDUs from the AP multi-link device on multiple links using the transceiver. Among the plurality of PPDUs, the ends of the PPDUs requesting immediate response are aligned. Specifically, the ends of PPDUs that only include frames that do not request an immediate response are not aligned with the ends of PPDUs that include frames that request an immediate response. If the AP multilink device performs a transmission in another link, the reception by the non-AP multilink device in one of the multiple links is limited due to internal leakage from the other link.

6. The non-AP multi-link device according to claim 5, wherein, The end of the PPDU that includes only frames that do not request an immediate response is no later than the end of the PPDU that includes frames that request an immediate response.

7. The non-AP multi-link device according to claim 5, wherein, The ACK strategy is used to determine whether a frame that requests an immediate response is a frame that requests an ACK.

8. The non-AP multi-link device according to claim 7, wherein, The frame requesting ACK is a data frame.

9. The non-AP multi-link device according to claim 5, wherein, The processor is configured to: access a channel using a channel access method on the plurality of links, the channel access method using a backoff counter, wherein the initial value of the backoff counter is set by an obtained random number, the backoff counter is decremented by 1 when the accessed channel is idle during the time slot period, and when the value of the backoff counter is 0, the station is allowed to perform transmission in the channel; and Even if the backoff counter reaches 0 in the channel access of any of the plurality of links, no transmission is performed on any of the links.

10. The non-AP multi-link device according to claim 9, wherein, When no transmission is performed on any of the links, the processor is configured to maintain the value of the backoff counter.

11. A method of operating a non-access point (AP) multilink device using multiple links, the method comprising: The non-AP multi-link device uses a transceiver to simultaneously receive multiple PPDUs from the AP multi-link device on the multiple links; as well as The transmission end time of the plurality of PPDUs is determined based on whether a frame requesting an immediate response is sent in the plurality of PPDUs. Among the plurality of PPDUs, the ends of the PPDUs requesting immediate response are aligned. Specifically, the ends of PPDUs that only include frames that do not request an immediate response are not aligned with the ends of PPDUs that include frames that request an immediate response. If the AP multilink device performs a transmission in another link, the reception by the non-AP multilink device in one of the multiple links is limited due to internal leakage from the other link.

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