Method and wireless communication terminal for transmitting and receiving data in a wireless communication system

Abstract

This invention relates to methods for transmitting and receiving data in a wireless communication system and to a wireless communication terminal. A method for transmitting frames in a multi-link device (MLD) of a wireless communication system is disclosed. The MLD transmits a request frame for mapping between traffic identifiers (TIDs) and links. The request frame includes first mapping information for setting a mapping relationship between at least one of a plurality of TIDs and at least one link, and information related to the number of the at least one TID requested to be mapped to the at least one link. The MLD then receives a response frame as a response to the request frame, wherein a first remaining TID, other than the at least one TID, effectively maintains its previously set mapping relationship with the link, or applies a default mapping relationship, and the first remaining TID is not indicated by the first mapping information to have a mapping relationship with a specific link.

Description

[0001] This application is a divisional application of patent application No. 202180068453.6 (International Application No. PCT / KR2021 / 010833), filed on April 6, 2023, with an international application date of August 13, 2021, entitled "Method for transmitting and receiving data in a wireless communication system and wireless communication terminal". Technical Field

[0002] This invention relates to a wireless communication system, and more specifically, to a wireless communication method and a wireless communication terminal for effectively signaling uplink multi-user information in a wireless communication system. Background Technology

[0003] In recent years, with the expansion of mobile device supply, Wireless LAN technology, which can provide fast wireless internet services to mobile devices, has gained attention. Wireless LAN technology allows mobile devices, including smartphones, tablets, laptops, portable multimedia players, embedded devices, and more, to wirelessly access the internet in their homes, offices, or other service areas based on short-range wireless communication technology.

[0004] Since using the 2.4 GHz frequency to support initial wireless LAN technology, the Institute of Electrical and Electronics Engineers (IEEE) 802.11 has commercialized or developed various technical standards. First, IEEE 802.11b, using the 2.4 GHz band, supported communication speeds of up to 11 Mbps. Compared to the significantly congested 2.4 GHz band, IEEE 802.11a, commercialized after IEEE 802.11b, used the 5 GHz band instead of 2.4 GHz to reduce interference and increased communication speeds to a maximum of 54 Mbps through the use of OFDM technology. However, a drawback of IEEE 802.11a is its shorter communication range compared to IEEE 802.11b. Furthermore, similar to IEEE 802.11b, IEEE 802.11g uses the 2.4 GHz frequency band to achieve communication speeds of up to 54 Mbps and meets backward compatibility, which is of significant interest. Moreover, it is superior to IEEE 802.11a in terms of communication range.

[0005] Furthermore, IEEE 802.11n has been developed as a technical standard to overcome the limitations of communication speed, a weakness identified in wireless LANs. IEEE 802.11n aims to improve network speed and reliability and extend the operating range of wireless networks. More specifically, IEEE 802.11n supports High Throughput (HT), with data processing speeds of up to 540 Mbps or higher, and further, it is based on Multiple Inputs Multiple Outputs (MIMO) technology, where multiple antennas are used on both sides of the transmitting and receiving units to minimize transmission errors and optimize data speed. Additionally, the standard can use a compilation scheme that superimposes multiple copies of the transmission to increase data reliability.

[0006] With the activation of the wireless LAN supply, and further, with the diversification of applications using wireless LAN, the need for new wireless LAN systems supporting much higher throughput (Very High Throughput, VHT) than those supported by IEEE 802.11n has gained attention. Among these, IEEE 802.11ac supports wide bandwidth (80 to 160 MHz) in the 5 GHz frequency band. The IEEE 802.11ac standard is defined only in the 5 GHz band, but initial 11ac chipsets even support operation in the 2.4 GHz band for backward compatibility with existing 2.4 GHz band products. Theoretically, according to this standard, wireless LAN speeds of up to 1 Gbps can be enabled for multiple stations, and single-link speeds can reach a minimum of 500 Mbps. This is achieved through the concept of expanding the wireless interface received by 802.11n, such as wider wireless frequency bandwidth (up to 160 MHz), more MIMO spatial streams (up to 8), multi-user MIMO, and high-density modulation (up to 256 QAM). Furthermore, IEEE 802.11ad has been offered as a solution for transmitting data using the 60GHz band instead of the existing 2.4GHz / 5GHz band. IEEE 802.11ad is a transmission standard that provides speeds of up to 7Gbps using beamforming technology and is suitable for high bit-rate motion streaming, such as large-scale data or uncompressed HD video. However, its drawback is that the 60GHz band is difficult to penetrate obstacles, limiting its use to devices operating in close proximity.

[0007] As a wireless LAN standard following 802.11ac and 802.11ad, the IEEE 802.11ax (High-Efficiency Wireless LAN (HEW)) standard, designed to provide efficient and high-performance wireless LAN communication in high-density environments with concentrated access points (APs) and terminals, is nearing completion. In 802.11ax-based wireless LAN environments, where high-density stations and access points (APs) are present, high-frequency efficiency communication should be provided indoors / outdoors, and various technologies have been developed to achieve this.

[0008] To support new multimedia applications, such as high-definition video and real-time gaming, new wireless LAN standards are being developed to maximize transmission rates. The IEEE 802.11be Extremely High Throughput (EHT), a 7th generation wireless LAN standard, is under development with the aim of supporting transmission rates up to 30Gbps in the 2.4 / 5 / 6 GHz band through wider bandwidth, increased spatial streaming, and multi-AP collaboration. Summary of the Invention

[0009] Technical issues

[0010] As described above, one aspect of the present invention is to provide high-speed wireless LAN services for new multimedia applications.

[0011] Furthermore, the present invention aims to provide a method for mapping traffic identifiers (TIDs) and links among multi-link devices, which are sets of logical entities.

[0012] Furthermore, the present invention aims to provide a method for implicitly determining the mapping relationship of TIDs that have not been indicated in the mapping process between TIDs and links.

[0013] The technical problems to be solved in this specification are not limited to those mentioned above, and other technical problems not mentioned can be clearly understood by those skilled in the art based on the following description.

[0014] Technical solution

[0015] A multi-link device (MLD) for a wireless communication system includes: a communication module; and a processor that controls the communication module, wherein the processor: transmits a request frame for mapping between traffic identifiers (TIDs) and links, the request frame including first mapping information for setting a mapping relationship between at least one of a plurality of TIDs and at least one link, and information related to the number of at least one TIDs requested to be mapped to the at least one link; and receives a response frame as a response to the request frame, wherein a first remaining TID, other than the at least one TID, effectively maintains a previously set mapping relationship with the link, or applies a default mapping relationship, the first remaining TID being determined by the first mapping information and not indicating a mapping relationship with a specific link.

[0016] Furthermore, in this invention, one of the at least one links is mapped to one or more of the at least one TIDs.

[0017] Furthermore, in this invention, the default mapping relationship is the state of TID mapping with all links, and the default mapping relationship applies when the first remaining TID is set to the default mapping relationship before the transmission of the request frame.

[0018] Furthermore, in this invention, the request frame also includes transmission direction information that displays the transmission direction for the at least one TID, wherein the plurality of TIDs are mapped only between the MLD and the peer MLD that transmits the request frame on the established link.

[0019] Furthermore, in this invention, the response frame indicates whether or not a mapping relationship between at least one of the plurality of TIDs and the at least one link is permitted.

[0020] Furthermore, in this invention, when the mapping relationship between at least one of the plurality of TIDs and the at least one link is allowed, the response frame does not include second mapping information for different mapping relationships between at least one of the plurality of TIDs and the at least one link.

[0021] Furthermore, in this invention, when the mapping relationship between at least one of the plurality of TIDs and the at least one link is not allowed, the response frame further includes second mapping information indicating a different mapping relationship from the first mapping relationship for at least one of the plurality of TIDs.

[0022] Furthermore, in this invention, the processor receives a management frame, which is transmitted only on the at least one link where the at least one TID and the mapping relationship are set.

[0023] Furthermore, in this invention, the management frame is transmitted based on the assigned Access Category (AC) and is transmitted on the at least one link regardless of the Access Category set on the at least one link.

[0024] Furthermore, in this invention, the processor receives a frame including second mapping information for setting a mapping relationship between one or more TIDs among the plurality of TIDs and one or more links, wherein a second remaining TID among the plurality of TIDs other than the one or more TIDs is indicated as having no preferred special mapping relationship or a preferred mapping relationship.

[0025] Furthermore, in this invention, the preferred special mapping relationship is either a previously set mapping relationship or the default mapping relationship.

[0026] Furthermore, in this invention, when the special mapping relationship does not have the default mapping relationship or the preferred mapping relationship, the response frame does not indicate the mapping relationship for the at least one TID and the TIDs that overlap in the second remaining TIDs.

[0027] Furthermore, the present invention provides a method comprising: transmitting a request frame for mapping between traffic identifiers (TIDs) and links, the request frame including first mapping information for setting a mapping relationship between at least one of a plurality of TIDs and at least one link, and information related to the number of the at least one TIDs requested to be mapped to the at least one link; and receiving a response frame as a response to the request frame, wherein a first remaining TID, other than the at least one TID, effectively maintains a previously set mapping relationship with the link, or applies a default mapping relationship, the first remaining TID being determined by the first mapping information and not indicating a mapping relationship with a specific link.

[0028] Beneficial effects

[0029] According to an embodiment of the present invention, the quality of service (QoS) of multi-link devices can be enhanced.

[0030] According to one embodiment of the present invention, a multi-link device can perform TID-to-link mapping.

[0031] According to one embodiment of the present invention, a multi-link device can perform quality-of-service management frame (QMF) to link mapping.

[0032] According to one embodiment of the present invention, when a multi-link device performs TID-to-link mapping, it may implicitly indicate a request / proposal.

[0033] According to one embodiment of the present invention, when a multi-link device changes its ML setup, it can manage the TID to link mapping.

[0034] The effects that can be obtained in this invention are not limited to those described above, and other effects not mentioned can be clearly understood by those skilled in the art from the following description. Attached Figure Description

[0035] Figure 1 The illustration shows a wireless LAN system according to an embodiment of the present invention.

[0036] Figure 2 The illustration shows a wireless LAN system according to another embodiment of the present invention.

[0037] Figure 3 The illustration shows the configuration of a station according to an embodiment of the present invention.

[0038] Figure 4 The diagram illustrates the configuration of an access point according to an embodiment of the present invention.

[0039] Figure 5 This diagram illustrates the process of setting up a link between a station and an access point.

[0040] Figure 6 The diagram illustrates the Carrier Sense Multiple Access (CSMA) / Collision Avoidance (CA) method used in wireless LAN communication.

[0041] Figure 7 An example of the format of the PLCP Protocol Data Unit (PPDU) for each of the various standard generations is shown.

[0042] Figure 8 Various Extremely High Throughput (EHT) Physical Protocol Data Unit (PPDU) formats according to embodiments of the present invention are illustrated, along with examples of methods for indicating such formats.

[0043] Figure 9This is a view illustrating a multi-link device according to an embodiment of the present invention.

[0044] Figure 10 An embodiment of a method for mapping traffic to its own STA (Link) by an MLD according to an embodiment of the present invention is shown.

[0045] Figure 11 An embodiment of a TID-to-link mapping method for establishing a connection between an AP MLD and a non-AP MLD is shown.

[0046] Figure 12 An embodiment of a TID-to-link mapping method that can be established between AP MLDs and non-AP MLDs is shown.

[0047] Figure 13 An example is shown of a TID-to-link mapping element that indicates a QMF that can be transmitted independently of the link.

[0048] Figure 14 An example of an MLD operation for establishing a QMF policy through a TID-to-link mapping is shown.

[0049] Figure 15 An example of the format of a TID-to-Link Mapping element is shown.

[0050] Figure 16 The TID to link mapping process according to an embodiment of the present invention is illustrated.

[0051] Figure 17 An example is shown in the TLD and link mapping that initiates the MLD indication (or proposal), where the responding MLD selectively responds to a subset of TIDs.

[0052] Figure 18 The response method shown allows (accepts) the initiating MLD to the link mapping from the TID proposed in response to the MLD reverse proposal.

[0053] Figure 19 An embodiment of the TID-to-Link Mapping Response frame transmitted from the AP MLD and the TID-to-Link Mapping negotiation process between the AP MLD and non-AP MLD is illustrated.

[0054] Figure 20 Another embodiment of the TID to link mapping element is shown.

[0055] Figure 21 An example of a TID-to-link mapping element is shown, which includes a variable-length TID field.

[0056] Figure 22 An embodiment of a method for managing the TID-to-link mapping of two MLDs by adding a setup link through a reset is shown.

[0057] Figure 23 An embodiment of a management method is shown that involves resetting the TID-to-link mapping of two MLDs for a link whose settings have been removed.

[0058] Figure 24 A flowchart illustrating an example of a method for mapping TIDs and links according to the present invention is shown. Detailed Implementation

[0059] In consideration of the functionality of this invention, the terminology used in this specification employs currently widely used and common terms; however, the terminology may change according to the intent, habits, and emergence of new technologies of those skilled in the art. Furthermore, in special cases, there are terms arbitrarily chosen by the applicant, and in such cases, their meaning will be explained in the corresponding descriptive section of the invention. Therefore, it should be understood that the terminology used in this specification should be analyzed not only based on the name of the term, but also on its substantive meaning and the content of the entire specification.

[0060] Throughout this specification, when an element is described as being "coupled" to another element, that element can be "directly coupled" to the other element or "electrically coupled" to the other element via a third element. Furthermore, unless explicitly stated otherwise, the word "comprising" will be understood to implicitly include the stated element, but does not exclude any other element. Additionally, limitations based on specific thresholds, such as "or above" or "or below," can be appropriately replaced by "greater than" or "less than," respectively. Hereinafter, in this invention, fields and subfields are used interchangeably.

[0061] Figure 1 The illustration shows a wireless LAN system according to an embodiment of the present invention.

[0062] A wireless LAN system comprises one or more Basic Service Sets (BSSs), and a BSS represents a collection of devices that have successfully synchronized with each other to communicate. Typically, BSSs can be divided into infrastructure BSSs and independent BSSs (IBSSs). Figure 1 The underlying structure BSS between them is shown.

[0063] like Figure 1 As shown, the infrastructure BSS (BSS1 and BSS2) includes one or more stations (STA1, STA2, STA3, STA4 and STA5), access points (AP-1 and AP-2) that serve as stations providing distribution services, and a distribution system (DS) that connects multiple access points (AP-1 and AP-2).

[0064] A station (STA) is a predetermined device comprising Medium Access Control (MAC) conforming to the IEEE 802.11 standard and a Physical Layer interface for wireless media, and broadly includes both non-access point (non-AP) stations and access points (APs). Furthermore, in this specification, the term "terminal" may be used to refer to a non-AP STA or an AP, or both. A station for wireless communication includes a processor and a communication unit, and according to embodiments, may further include a user interface unit and a display unit. The processor can generate frames to be transmitted via a wireless network, or process frames received via a wireless network, and further performs various processes for controlling the station. Additionally, the communication unit is functionally connected to the processor and transmits and receives frames via the wireless network for the station. According to the invention, "terminal" can be used as a term including user equipment (UE).

[0065] An Access Point (AP) is an entity that provides access to a Distributed System (DS) via wireless media used by associated stations. In an infrastructure BSS, communication between non-AP stations is generally performed via the AP; however, direct communication between non-AP stations is even permitted when a direct link is configured. In this invention, AP is used as a concept including Personal BSS Coordination Point (PCP), and broadly can include concepts such as a central controller, base station (BS), node B, base transceiver system (BTS), or site controller. In this invention, AP can also be referred to as a base station wireless communication terminal. The term base station wireless communication terminal can be used broadly to include AP, base station, eNodeB (eNB), and transport point (TP). Furthermore, a base station wireless communication terminal can include various types of wireless communication terminals that allocate communication medium resources and perform scheduling in communication with multiple wireless communication terminals.

[0066] Multiple infrastructure BSSs can be interconnected via a distributed system (DS). In this case, the multiple BSSs connected via the distributed system are called an Extended Service Set (ESS).

[0067] Figure 2 The illustration shows a standalone BSS according to another embodiment of the present invention, which is a wireless LAN system. Figure 2 In the embodiments, with Figure 1 Same or corresponding Figure 1 Repeated descriptions of certain embodiments will be omitted.

[0068] Because in Figure 2 The BSS3 shown in the diagram is an independent BSS and does not include the AP. All stations STA6 and STA7 are not connected to the AP. Independent BSSs are not allowed to access the distributed system and form a self-contained network. Within an independent BSS, the corresponding stations STA6 and STA7 can be directly interconnected.

[0069] Figure 3 This is a block diagram illustrating the configuration of station 100 according to an embodiment of the present invention. (As shown in...) Figure 3 As shown in the figure, the station 100 according to an embodiment of the present invention may include a processor 110, a communication unit 120, a user interface unit 140, a display unit 150, and a memory 160.

[0070] First, the communication unit 120 transmits and receives wireless signals, such as wireless LAN packets, and can be embedded in the station 100 or provided as a peripheral. According to embodiments, the communication unit 120 may include at least one communication module using different frequency bands. For example, the communication unit 120 may include communication modules with different frequency bands (such as 2.4 GHz, 5 GHz, 6 GHz, and 60 GHz). According to embodiments, the station 100 may include communication modules using frequency bands of 7.125 GHz or higher, and communication modules using frequency bands of 7.125 GHz or lower. Each communication module can perform wireless communication with an AP or external station according to the wireless LAN standard of the frequency band supported by the respective communication module. The communication unit 120 may operate only one communication module at a time, or multiple communication modules simultaneously, depending on the performance and requirements of the station 100. When the station 100 includes multiple communication modules, each communication module can be implemented by an independent component, or multiple modules can be integrated into a single chip. In embodiments of the invention, the communication unit 120 may represent an RF communication module for processing radio frequency (RF) signals.

[0071] Secondly, the user interface unit 140 includes various types of input / output devices provided in the station 100. That is, the user interface unit 140 can receive user input using various input devices, and the processor 110 can control the station 100 based on the received user input. Furthermore, the user interface unit 140 can execute outputs based on commands from the processor 110 using various output devices.

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

[0073] The processor 110 of the present invention can execute various commands or programs and process data in station 100. Furthermore, the processor 110 can control various units of station 100 and control data transmission / reception within the units. According to an embodiment of the present invention, the processor 110 can execute a program for accessing an AP stored in memory 160 and receive communication configuration messages transmitted by the AP. Furthermore, the processor 110 can read information about the priority conditions of station 100 included in the communication configuration messages and request access to the AP based on the information about the priority conditions of station 100. The processor 110 of the present invention can represent the main control unit of station 100, and according to an embodiment, the processor 110 can represent a control unit for individually controlling certain components of station 100 (e.g., communication unit 120, etc.). That is, the processor 110 can be a modem or modulator / demodulator for modulating wireless signals transmitted to communication unit 120 and demodulating wireless signals received from communication unit 120. The processor 110 controls various operations of wireless signal transmission / reception of station 100 according to an embodiment of the present invention. Detailed embodiments will be described below.

[0074] exist Figure 3 The station 100 illustrated in the diagram is a block diagram according to an embodiment of the present invention, where the separate blocks are illustrated as logically distinct device elements. Therefore, the device elements can be installed on a single chip or multiple chips depending on the device design. For example, the processor 110 and the communication unit 120 can be implemented as a single chip or as separate chips. Furthermore, in embodiments of the present invention, certain components of the station 100, such as the user interface unit 140 and the display unit 150, can be selectively provided in the station 100.

[0075] Figure 4 This is a block diagram illustrating the configuration of an AP 200 according to an embodiment of the present invention. (As shown in...) Figure 4 As illustrated in the figure, the AP 200 according to an embodiment of the present invention may include a processor 210, a communication unit 220, and a memory 260. Figure 4 In the AP200 components, and... Figure 2 The components of station 100 are the same or correspond to Figure 2 Repeated descriptions of parts of station 100 will be omitted.

[0076] Reference Figure 4 The AP 200 according to the invention includes a communication unit 220 that operates a BSS in at least one frequency band. (As in...) Figure 3As illustrated in the embodiments, the communication unit 220 of AP 200 may also include multiple communication modules using different frequency bands. That is, AP 200 according to embodiments of the present invention may together include two or more communication modules in different frequency bands (e.g., 2.4 GHz, 5 GHz, 6 GHz, and 60 GHz). Preferably, AP 200 may include communication modules using frequency bands of 7.125 GHz or higher, and communication modules using frequency bands of 7.125 GHz or lower. Each communication module can perform wireless communication with the station according to the wireless LAN standard of the frequency band supported by the respective communication module. Communication unit 220 may operate only one communication module at a time, or operate multiple communication modules simultaneously, depending on the performance and requirements of AP 200. In embodiments of the present invention, communication unit 220 may represent a radio frequency (RF) communication module for processing RF signals.

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

[0078] Figure 5 This is a diagram illustrating the process of setting up a link between a STA and an AP.

[0079] Reference Figure 5In a broad sense, the link between STA 100 and AP 200 is set up through three steps: scanning, authentication, and association. First, the scanning step is where STA 100 obtains access information from the BSS operated by AP 200. Methods for performing the scan include passive scanning, where AP 200 obtains information by using periodically transmitted beacon messages (S101), and active scanning, where STA 100 transmits a probe request to AP (S103) and obtains access information by receiving a probe response from AP (S105).

[0080] STA 100, having successfully received wireless access information during the scanning step, performs an authentication step by transmitting an authentication request (S107a) and receiving an authentication response from AP 200 (S107b). After performing the authentication step, STA 100 performs an association step by transmitting an association request (S109a) and receiving an association response from AP 200 (S109b). In this specification, association primarily refers to wireless association; however, the invention is not limited thereto, and association can broadly include both wireless and wired associations.

[0081] Simultaneously, the 802.1X-based authentication step (S111) and the IP address acquisition step via DHCP (S113) can be performed additionally. Figure 5 In this context, authentication server 300 is the server that handles 802.1X-based authentication for STA 100, and can exist in a physical association with AP 200 or as a standalone server.

[0082] Figure 6 This is a diagram illustrating the Carrier Sense Multiple Access (CSMA) / Collision Avoidance (CA) method used in wireless LAN communication.

[0083] Terminals performing wireless LAN communication check if a channel is busy by performing carrier sensing before transmitting data. When a wireless signal with a preset strength or greater is sensed, the corresponding channel is determined to be busy, and the terminal delays access to that channel. This process is called Clear Channel Assessment (CCA), and the level at which the corresponding signal is sensed is called the CCA threshold. When a terminal receives a wireless signal with a CCA threshold or higher that indicates it is a receiver, the terminal processes the received wireless signal. Conversely, when no wireless signal is detected in the corresponding channel, or when a wireless signal with a strength less than the CCA threshold is detected, the channel is determined to be idle.

[0084] When the channel is determined to be idle, each terminal with data to transmit performs a backoff procedure after an inter-frame space (IFS) period, the duration of which depends on the specific terminal, such as an Arbitration IFS (AIFS), PCF IFS (PIFS), etc. According to this embodiment, AIFS can be used as a component to replace the existing DCF IFS (DIFS). During the idle period of the channel, each terminal waits while reducing the time slot duration by a random number determined by the respective terminal, and terminals that have completely exhausted their time slots attempt to access the corresponding channel. Thus, the interval during which each terminal performs the backoff procedure is called the contention window interval.

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

[0086] In this invention, the terminal may be referred to as a non-AP STA, AP STA, STA, receiving device, or transmitting device, and the invention is not limited thereto. Furthermore, in this invention, an AP STA may be referred to as an AP.

[0087] <Examples of various PPDU formats>

[0088] Figure 7 The illustration shows 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 of the HE PPDU format of 802.11ax, and Figure 7 (c) illustrates an embodiment based on a non-traditional PPDU (i.e., EHT PPDU) format 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.

[0089] Reference Figure 7 (a) The preamble of a conventional PPDU includes a conventional short training field (L-STF), a conventional long training field (L-LTF), and a conventional signal field (L-SIG). In embodiments of the present invention, L-STF, L-LTF, and L-SIG may be referred to as conventional preambles.

[0090] Reference Figure 7(b) The HE PPDU preamble also includes, in a conventional preamble, 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 embodiments of the present invention, RL-SIG, HE-SIG-A, HE-SIG-B, HE-STF, and HE-LTF can be referred to as HE preambles. The detailed configuration of the HE preamble can be modified according to the HE PPDU format. For example, HE-SIG-B can be used only in the HE MU PPDU format.

[0091] Reference Figure 7 (c) The EHT PPDU also includes, in its conventional preamble, a Repeated Legacy Short Training field (RL-SIG), a Universal Signal field (U-SIG), 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 embodiments of the invention, RL-SIG, EHT-SIG-A, EHT-SIG-B, EHT-STF, and EHT-LTF may be referred to as EHT preambles. The specific configuration of non-conventional preambles can be modified according to the EHT PPDU format. For example, EHT-SIG-A and EHT-SIG-B may be used only in a portion of the EHT PPDU format.

[0092] 64-FFT OFDM is applied to the L-SIG field included in the preamble of the PPDU, and the L-SIG field comprises a total of 64 subcarriers. Of these 64 subcarriers, 48 ​​subcarriers other than the guard subcarrier, DC subcarrier, and pilot subcarrier are used for L-SIG data transmission. BPSK and a modulation and coding scheme (MCS) with a code rate of 1 / 2 are applied to the L-SIG, thus the L-SIG can include a total of 24 bits of information. Figure 7 (d) shows the configuration of the 24-bit information of L-SIG.

[0093] Reference Figure 7 (d) L-SIG includes the L_RATE and L_LENGTH fields. The L_RATE field consists of 4 bits and indicates the MCS used for data transmission. Specifically, the L_RATE field indicates a value of 6 / 9 / 12 / 18 / 24 / 36 / 48 / 54 Mbps obtained by combining modulation schemes such as BPSK / QPSK / 16-QAM / 64-QAM with inefficient values ​​such as 1 / 2, 2 / 3, 3 / 4, etc. The total length of the corresponding PPDU can be indicated by combining the information from the L_RATE and L_LENGTH fields. In non-traditional PPDU formats, the L_RATE field is configured with a minimum rate of 6 Mbps.

[0094] The L_LENGTH field can be allocated a total of 12 bits per byte, can be transmitted via signaling up to 4095, and can indicate the length of the corresponding PPDU by combining it with the L_RATE field. In this case, traditional and non-traditional terminals can use different methods to interpret the L_LENGTH field.

[0095] First, the method for analyzing the length of the corresponding PPDU using the L_LENGTH field in traditional or non-traditional terminals is as follows. When the value of the L_RATE field is set to indicate 6 Mbps, 3 bytes (i.e., 24 bits) can be transmitted during the 4 μs duration of one symbol in a 64FFT. Therefore, the 3 bytes corresponding to the SVC field and the tail field are added to the value of the L_LENGTH field, and the sum is divided by the 3 bytes of transmission as one symbol to obtain the number of symbols based on 64FFT after L-SIG. Multiplying the obtained number of symbols by 4 μs (i.e., the length of one symbol), and then adding the transmission time of L-STF, L-LTF, and L-SIG (20 μs), the length of the corresponding PPDU, i.e., the reception time RXTIME, is obtained. This can be represented by Equation 1 below.

[0096] [Equation 1]

[0097] in this case, This represents the smallest natural number greater than or equal to x. Since the maximum value for the L_LENGTH field is 4095, the length of the PPDU can be set to up to 5.464 ms. Non-traditional terminals transmitting PPDUs should set the L_LENGTH field as shown in Equation 2 below.

[0098] [Equation 2]

[0099] Here, TXTIME is the total transmission time that makes up the corresponding PPDU, and is represented by Equation 3 below. In this case, TX represents the transmission time of X.

[0100] [Equation 3]

[0101] Referring to the equation above, the length of the PPDU is calculated based on the rounded-up value of L_LENGTH / 3. Therefore, for random values ​​of k, three different values ​​of L_LENGTH={3k+1, 3k+2, 3(k+1)} indicate the same PPDU length.

[0102] Reference Figure 7 (e) The Universal SIG (U-SIG) field continues to exist in subsequent generations of EHTPPDU and Wireless LAN PPDU, and is used to classify PPDUs of all generations, including 11be. U-SIG is based on 64 FFT OFDM 2 symbols and can transmit a total of 52 bits of information. Of these 52 bits, excluding the 9 bits for CRC / tail, the remaining 43 bits are primarily divided into Version Independent (VI) and Version Dependent (VD) fields.

[0103] The VI bits enable the current bit configuration to be maintained subsequently, so that even if a next-generation PPDU is defined, current 11be terminals can obtain information about the PPDU through the VI fields of the PPDU. For this purpose, the VI fields include 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 subsequent generations of wireless LAN standards into versions. The value for 11be is 000b. The UL / DL field identifies whether the PPDU is an uplink / downlink PPDU. The BSS color indicates the identifier of each BSS defined in 11ax and has a value of 6 bits or more. TXOP indicates the Transmit Opportunity Duration transmitted in the MAC header. The PPDU can infer the length of the TXOP included in the PHY header by adding the TXOP, without having to decode the MPDU, and the TXOP has a value of 7 bits or more.

[0104] The VD field contains signaling information useful only for the 11be version of the PPDU and can include fields common to any PPDU format, such as the PPDU format and BW, as well as fields defined differently for each PPDU format. The PPDU format is a classifier that categorizes EHT Single User (SU), EHT Multiple User (MU), EHT Trigger-based (TB), and EHT Extended Range (ER) PPDUs. The BW field signals five basic PPDU BW options (BW, which can be set to 20 MHz) at 20 MHz, 40 MHz, 80 MHz, 160 MHz (80+80 MHz), and 320 MHz (160+160 MHz). The signaling is expressed as a power of 2 (which can be referred to as the basic BW), and various remaining PPDU BWs configured via preamble puncturing. After signaling at 320MHz, signaling can be executed in some 80MHz punctured form. The punctured and modified channel type can be signaled directly in the BW field, or it can be signaled using the BW field along with fields appearing after the BW field (e.g., fields within the EHT-SIG field). If the BW field is configured with 3 bits, a total of 8 BW signalings can be executed, and therefore up to 3 signalings can be executed in punctured mode. If the BW field is configured with 4 bits, a total of 16 BW signalings can be executed, and therefore up to 11 signalings can be executed in punctured mode.

[0105] The fields following the BW field vary depending on the type and format of the PPDU. MU PPDUs and SU PPDUs can be signaled in the same PPDU format. Fields used for classification between MU and SU PPDUs can precede the EHT-SIG field, and additional signaling can be applied to this field. Both SU and MU PPDUs include the EHT-SIG field, but some fields not needed in the SU PPDU can be compressed. Information about fields that have been compressed can be omitted or can have a smaller size than the original fields included in the MU PPDU. For example, in the case of SU PPDUs, common fields of EHT-SIG can be omitted or replaced, or the SU PPDU can have a different configuration, where user-specific fields are replaced, reduced to one, etc.

[0106] Alternatively, the SU PPDU may also include a compression field indicating whether compression is performed, and a portion of a field (e.g., the RA field, etc.) may be omitted depending on the value of the compression field.

[0107] If a portion of the EHT-SIG field of the SU PPDU is compressed, the information to be included in the compressed field can also be signaled in the uncompressed field (e.g., the common field, etc.). The MU PPDU corresponds to a PPDU format for simultaneous reception by multiple users, and therefore requires the EHT-SIG field to be transmitted after the U-SIG field, and the amount of information transmitted can vary. That is, multiple MU PPDUs are transmitted to multiple STAs, such that each STA must identify the location of the RU to which the MU PPDU was transmitted, the STA to which the RU was assigned, and whether the transmitted MU PPDU has been transmitted to the STA itself. Therefore, the AP must transmit this information by including the above information in the EHT-SIG field. For this purpose, the information for valid 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 about the size and location of the RU assigned to each user.

[0108] In the case of SU PPDU, multiple RUs can be assigned to a STA, and these RUs can be consecutive or discontinuous. If the RUs assigned to the STA are discontinuous, the STA should identify the intermediate punched RUs in order to effectively receive the SUPPDU. Therefore, the AP can transmit a SU PPDU that includes information about the punched RUs among those assigned to the STA (e.g., the punching pattern of the RUs). That is, in the case of SU PPDU, a punching mode field can be included in the EHT-SIG field. This punching mode field includes information indicating the punching pattern in bitmap format and whether a punching mode has been applied, and the punching mode field can signal the type of discontinuous channel occurring within the bandwidth.

[0109] The types of discontinuous channels notified by signals are limited, and the BW and discontinuous channel information of the SU PPDU are indicated by the combination of the BW field value and the SU PPDU. For example, the SU PPDU is a PPDU transmitted only to a single terminal, so that the STA can identify the bandwidth allocated to itself via the BW field contained in the PPDU, and the SU PPDU can identify the puncturing resources in the allocated bandwidth via the puncturing mode field of the EHT-SIG field or U-SIG field contained in the PPDU. In this case, the terminal can receive the PPDU in the remaining resource units after excluding the special channels of the punctured resource units. Multiple RUs allocated to the STA can be configured by different frequency bands or tones.

[0110] To reduce the signaling overhead of the SU PPDU, only a limited number of discontinuous channel types are signaled. Puncture could be performed on each 20MHz sub-channel, so if puncturing is performed on a BW with a large number of 20MHz sub-channels (such as 80, 160, and 320MHz), then in the case of 320MHz, the discontinuous channel type (if puncturing only the edge 20MHz is also considered discontinuous) should be signaled by indicating whether each of the remaining 15 20MHz sub-channels after excluding the primary channel is used. Thus, considering the low transmission rate of the signaling section, allocating 15 bits to signal the discontinuous channel type transmitted by a single user could be excessive signaling overhead.

[0111] This invention proposes a technique for signaling the discontinuous channel type of a SU PPDU, and illustrates the discontinuous channel type determined according to the proposed technique. This invention also proposes a technique for signaling each of the primary 160MHz and secondary 160MHz puncture types in a 320MHz BW configuration of a SU PPDU.

[0112] Furthermore, embodiments of the present invention propose a technique for configuring the PPDU indicated by the preamble piercing (BW) value differently based on the PPDU format notified by signaling in the PPDU format field. Assuming the BW field is 4 bits, and in the case of EHT SUPPDU or TB PPDU, EHT-SIG-A (symbol 1) can be notified by signaling after U-SIG, or EHT-SIG-A can be notified at all. Therefore, considering this, it is necessary to fully signal up to 11 piercing modes via the BW field of U-SIG alone. However, in the case of EHT MU PPDU, EHT-SIG-B is notified by signaling after U-SIG, thus allowing up to 11 piercing modes to be signaled in a different way than the SU PPDU method. In the case of EHT ER PPDU, the BW field can be configured to be 1 bit to signal whether the EHT ER PPDU uses a 20MHz or 10MHz band PPDU.

[0113] Figure 7 Figure (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 transmitted 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-BDCM, the number of SIG-B symbols, SIG-B compression, and the number of EHT-LTF symbols, etc.

[0114] 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.

[0115] 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.

[0116] 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.

[0117] 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 a trigger frame. Unlike the EHT SU PPDU, the EHT-SIG-A field is not located after the U-SIG field in the EHT PPDU.

[0118] 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 transmit PPDUs to one or more STAs. In the EHT MU PPDU format, the HE-SIG-B field may be located after the U-SIG field.

[0119] Figure 8 (d) shows an example of the EHT ERSU PPDU format, which is used for transmission with a single user across an extended range of STAs. Figure 8 Compared to the EHT SU PPDU described in (a), the EHT ER SU PPDU can be used for single-user transmission with a wider range of STAs, and the U-SIG field can be repeatedly positioned on the timeline.

[0120] Figure 8 The EHT MU PPDU described in (c) can be used by the AP to perform downlink transmissions to multiple STAs. Here, the EHT MU PPDU may include scheduling information, enabling multiple STAs to simultaneously receive PPDUs transmitted from the AP. The EHT MU PPDU may transmit the transmitter and / or receiver AID information of the PPDU transmitted via the user-specific field of EHT-SIG-B to the STA. Therefore, multiple terminals that have received the EHT MU PPDU can perform spatial reuse operations based on the AID information included in the user-specific field of the received PPDU preamble.

[0121] Specifically, the resource unit allocation (RA) field in the HE-SIG-B field of the HE MU PPDU can include information about the configuration (e.g., the partitioning of resource units) of resource units within a specific bandwidth (e.g., 20MHz) of the frequency axis. In other words, the RA field can indicate the configuration of resource units partitioned within the bandwidth used for the transmission of the HE MU PPDU so that the STA can receive the PPDU. Information about the STA allocated (or specified) to each partitioned resource unit can be included in the user-specific fields of the EHT-SIG-B field for transmission to the STA. That is, the user-specific fields can include one or more user fields corresponding to the respective partitioned resource unit.

[0122] For example, the user field corresponding to at least one resource unit among multiple segmented resource units used for data transmission may include the AID of the receiver or transmitter, and the user field corresponding to the remaining resource units not used for data transmission may include a pre-configured null STA ID.

[0123] Figure 8 Two or more PPDUs shown can be indicated by values ​​representing the same PPDU format. That is, two or more PPDUs can be indicated by the same value in the same PPDU format. For example, EHT SU PPDU and EHT MU PPDU can be indicated by the same value in the U-SIG PPDU format subfield. In this case, EHT SU PPDU and EHT MU PPDU can be distinguished by the number of STAs receiving the PPDU. For example, a PPDU receiving only one STA can be identified as an EHT SU PPDU, and when the number of STAs is set to receive two or more STAs, the PPDU can be identified as an EHT MU PPDU. In other words, they can be indicated by the same subfield value. Figure 8 The two or more PPDU formats shown.

[0124] In addition, it can be omitted Figure 8 The fields shown in the diagram may be partially or partially information of the fields, and the case where partially or partially information of the fields is omitted may be defined as compression mode or compressed mode.

[0125] Figure 9 This is a diagram illustrating a multi-link device according to an embodiment of the present invention.

[0126] Reference Figure 9The concept of a device to which one or more STAs belong can be defined. As another embodiment of the invention, devices to which more than one STA (i.e., two or more STAs) belong can be defined. In this case, the device can be a logical concept. Therefore, a device to which one or more STAs with this concept belong can be referred to as a multi-link device (MLD), a multi-band device, or a multi-link logical entity (MLLE).

[0127] Alternatively, the device described above can be referred to as a multi-link entity (MLE). Furthermore, the MLD can have a medium access control service access point (MAC SAP) to logical link control (LLC), and the MLD can have a MAC data service.

[0128] A STA included in an MLD can operate on one or more links or channels. That is, a STA included in an MLD can operate on multiple channels that are different from each other. For example, a STA included in an MLD can operate using channels in different frequency bands such as 2.4 GHz, 5 GHz, and 6 GHz. Thus, MLD can benefit from channel connectivity and can improve the performance of the entire network. In existing wireless LANs, operation is typically on a single link. MLD operation can gain more channel access opportunities by using multiple links, or, considering channel conditions, the STA can effectively operate on multiple links.

[0129] Furthermore, when the STA belonging to an MLD is an AP, the MLD to which the AP belongs can be an AP MLD. However, when the STA belonging to an MLD is a non-AP STA, the MLD to which the non-AP belongs can be a non-AP MLD.

[0130] Reference Figure 9 An MLD can exist that includes multiple STAs, and these multiple STAs within the MLD can operate on multiple links. Figure 9Among them, the MLD including APs (i.e., AP1, AP2, and AP3) can be called AP MLD, and the MLD including non-AP STAs (i.e., non-AP STA1, non-AP STA2, and non-AP STA3) can be called non-AP MLD. The STAs included in the MLD can operate on Link 1, Link 2, Link 3, or some of Links 1 to 3.

[0131] According to an embodiment of the present invention, multi-link operation may include a multi-link setup operation. The multi-link setup operation may correspond to the association operation performed in a single-link operation. In order to exchange frames in multiple links, multiple links may be set up first. The multi-link setup operation may be performed using a multi-link setup element. Here, the multi-link configuration element may include capability information related to multi-link, and the capability information may include information related to whether another STA included in the MLD can transmit frames through another link while a STA included in the MLD receives frames through a certain link. That is, the capability information may include information related to whether the STAs (non-AP STAs and / or AP STAs) included in the MLD can transmit / receive frames simultaneously in different transmission directions through the link. In addition, the capability information may further include information related to the available links or operating channels. The multi-link setup may be set through negotiation between peer STAs, and the multi-link operation may be set through one link.

[0132] According to an embodiment of the present invention, there may be a mapping relationship between the TID and the links of the MLD. For example, when the TID and the link are mapped, the TID may be transmitted through the mapped link. The mapping between the TID and the link may be implemented based on the transmission direction. For example, the mapping may be performed in both directions between MLD1 and MLD2. In addition, there may be a default setting for the mapping between the TID and the link. For example, the mapping between the TID and the link may be such that basically all TIDs are mapped to a certain link.

[0133] <Wi-Fi Quality of Service Support>

[0134] Wi-Fi (IEEE 802.11) data rates have increased dramatically with each new protocol version, with the recently finalized 802.11ax expected to support data rates up to approximately 10 Gbps. This improved Wi-Fi data rate is attributed to enhanced hardware performance, with the PHY protocol supporting wider bandwidth (BW) and higher MCS processing, and the ability to utilize multiple antennas.

[0135] However, despite such a dramatic increase in data rates, Wi-Fi still suffers from transmission latency issues. All communication systems, including Wi-Fi, support limited data rates, resulting in a certain amount of latency when transmitting traffic. However, Wi-Fi's latency is problematic because it is unpredictable. In other words, while communication systems using dedicated communication resources (wired or wireless licensed bands) can predict the required latency based on the amount of traffic to be transmitted, communication systems using unlicensed bands (such as Wi-Fi) may experience unpredictable latency when the medium is occupied by other devices. If such unpredictable latency occurs, short-lifetime traffic (such as voice traffic) may lose its utilization, making it difficult to predict improvements in Quality of Service (QoS) even if Wi-Fi supports high data rates.

[0136] The IEEE 802.11 standardization body has continuously developed MAC protocols to overcome the aforementioned restrictions on unlicensed frequency bands. The Enhanced Distributed Channel Access (EDCA) introduced in 802.11e can be considered one of these achievements. In the following explanation, for ease of explanation, QoS AP will be written as AP, QoS STA as STA, and QoS BSS as BSS. Therefore, referring to AP can be interpreted as referring to a QoS AP.

[0137] EDCA provides a mechanism for classifying and managing traffic into four access categories (ACs) based on its characteristics. These four ACs are AC_VO (AC Voice), AC_VI (AC Video), AC_BE (AC Best Effort), and AC_BK (AC Background). Each AC can have different contention windows (CW), transmission opportunities (TXOP), and AIFSN parameters. Simply put, EDCA is a mechanism that adjusts the transmission priority of traffic using each AC by differentiating the CW, TXOP, and AIFSN parameters for each of the four ACs. To this end, EDCA can map the traffic (MSDU) to be served by the MAC to one of the four ACs based on traffic category (TC) or traffic stream (TS). Traffic mapped to one of the four ACs via EDCA is then classified and managed in four queues for each AC. In this case, the four queues can be physically inseparable but logically separate.

[0138] AC_VO is an AC that, while having a relatively small absolute volume of traffic (e.g., voice traffic), can be used for traffic sensitive to transmission latency. It also has relatively small CW and AIFSN parameter values ​​to increase the probability of traffic being served prior to other ACs. However, because AC_VO's TXOP parameter is limited to a relatively small value compared to other ACs, it can only guarantee shorter transmission times than other ACs.

[0139] AC_VI is a more robust protocol for transmission latency than voice traffic, but it can still be used for traffic that requires low-latency transmission and handles large volumes of data (such as video). AC_VI has larger CW and AIFSN parameter values ​​than AC_VO, but smaller than other ACs, while TXOP is approximately twice as long as AC_VI.

[0140] AC_BE is an AC that can be used for traffic with high transmission latency. Most general traffic, except for voice data and streaming video data, can be classified as AC_BE. AC_BE uses CW and AIFSN parameters with larger values ​​than AC_VO and AC_VI. Furthermore, AC_BE does not have an additional TXOP, therefore it cannot use the TXOP transmission sequence of receiving an ACK response after transmitting a PPDU and retransmitting the PPDU after SIFS.

[0141] AC_BK is an AC type similar to AC_BE, but with strong transmission delay and can be used for traffic with lower priority than BE traffic. AC_BK uses the same CW parameter value as AC_BE, but uses a larger AIFSN parameter value. Furthermore, like AC_BE, AC_BK does not have an additional TXOP, so TXOP transmission sequences cannot be used.

[0142] The above four types of EDCA ACs are mapped to 802.1D user-priority (UP), and the EDCA AC is determined based on the UP value of the wired received traffic or the TID of the MSDU indicated from the higher level. In this case, when the TID of the MSDU indicates a value from 0 to 7, the value indicated by the TID can correspond one-to-one with UP.

[0143] The mapping rules between 802.1D UP and EDCA AC are shown in Table 1 below.

[0144] [Table 1]

[0145] In addition, the above four EDCA ACs define their own default CW (CWmin, CWmax), AIFSN, and TXOP parameters in the standard. The parameter values ​​of each AC are changed by AP, so different values ​​can be used in each BSS.

[0146] Using the EDCA mechanism, Wi-Fi traffic is stored in one of four queues corresponding to four ACs. Traffic can only be transmitted to the destination device when the AC containing the traffic successfully obtains channel access based on competition with other ACs. At this time, channel access operations between the EDCA functions (EDCAF) corresponding to the ACs can be performed through competition, using the access parameters (CW[AC], AIFSN[AC]) allocated to each AC during the competition. The channel access competition operation performed for each AC is the same as that of DCF. If there is no traffic in the queue required for a specific AC, that specific AC cannot participate in the competition.

[0147] However, as mentioned above, since the CW and AIFSN parameter values ​​used by each AC are different, AC_VO with the smallest CW and AIFSN parameters has a higher probability of successfully gaining channel access in competition with other ACs, and thus AC_VO's traffic is more likely to be served with priority over traffic from other ACs.

[0148] In addition, when internal collisions occur between ACs, the EDCA machine uses the AC with higher priority (see Table 1) and stipulates internal competition rules such as increasing the CW of other ACs that caused the collision, and rules that include the traffic of other ACs that did not win the competition (primary AC) and constitute PPDUs.

[0149] In addition to EDCA mentioned above, the 802.11 MAC protocol also defines an HCF controlled channel access (HCCA) mechanism for QoS management. HCCA provides a centralized / hybrid coordinator function to ensure the QoS of traffic streams (TS) for applications that require periodic services (such as voice and video). Furthermore, there are Service Period Channel Access (SPCA) and Dynamic Allocation of Service Period mechanisms, but these can only utilize DMG STAs. EDCA, mentioned earlier, is arguably the most representative Wi-Fi QoS MAC protocol.

[0150] <Quality of Service (QoS) MLD Operations>

[0151] When considering the operation of the EDCA mechanism described above, it can be seen that the purpose of applying different CW and AIFSN parameters to each AC is to adjust the transmission priority based on traffic characteristics.

[0152] Consider passing Figure 9 The described structure of an MLD involves one or more STAs used in different links, so each STA in an MLD can have its own independent transmission queue. In this case, the queues can be logically separate, which means that an MLD can be a logical concept.

[0153] EDCA separates and utilizes queues for the four ACs, thus mimicking the principle of enhanced QoS service. MLD, to enhance QoS, considers the traffic it serves and the characteristics of that traffic, and can map it to one of the STAs it uses. In other words, similar to the EDCA mechanism mapping traffic to one of the four ACs, MLD can map traffic to one of the STAs it uses. In this case, the operation of MLD mapping specific traffic to a specific STA can be understood as MLD mapping specific traffic to the link used by that specific STA. To make this easier to understand, through... Figure 10 Describes a method for MLD to enhance QoS using multiple STAs (Links).

[0154] Figure 10 An embodiment of a method for mapping traffic to its own STA (Link) by an MLD according to an embodiment of the present invention is shown.

[0155] Reference Figure 10 (a) AP MLD and (b) non-AP MLD are AP1, AP2, AP3 and AP4 as 4 STAs, and non-AP STA1, non-AP STA2, non-AP STA3 and non-AP STA4 as MLDs, respectively. The 4 STAs of the two MLDs can be associated with each other.

[0156] If the AP MLD uses the queues of its four STAs (AP1, AP2, AP3, and AP4) in a manner similar to the AC-based queueing in EDCA, then as shown in Table 1, traffic mapped to the AP1 queue uses AC_BK, traffic mapped to the AP2 queue uses AC_BE, traffic mapped to the AP3 queue uses AC_VI, and traffic mapped to the AP4 queue uses AC_VO. In this way, traffic mapped to each STA can be served according to the channel access procedure performed by each STA, thus traffic with different ACs will not be affected by the transmission delays incurred by traffic from other ACs during transmission. That is, the QoS enhancement effect obtained by MLD by separating STAs mapped according to traffic characteristics is similar to EDCA assigning transmission priority to traffic with higher priority, but with the difference that traffic with different ACs can be unaffected by each other's transmission.

[0157] On the other hand, since the channel quality and load conditions of the links used by each STA of MLD may be different, the PHY performance and operating bandwidth of each STA may be different. Therefore, depending on which STA MLD maps special traffic to, the BW and MCS of the PPDU of the special traffic may be different.

[0158] For example, if AP1, as a STA of AP MLD, operates in the 2.4 GHz band, AP1 can have an operating bandwidth of up to 40 MHz, and AP4, as another STA of AP MLD, operates in the 6 GHz band, AP4 can use up to 320 MHz of bandwidth as its operating bandwidth. In this case, if the MLD needs to map traffic requiring high throughput and low latency, it can enhance QoS by mapping that traffic to AP4. Thus, by performing STA mapping that takes into account the characteristics of the traffic it serves, the MLD can achieve the effect of differentiating not only the transmission priority of the traffic but also the amount of resources (hardware and frequency) available during transmission.

[0159] Mapping of traffic identifiers (TIDs) to links>

[0160] pass Figure 10 One embodiment described herein illustrates how MLD, for QoS enhancement, can perform traffic mapping for the STA (link) it utilizes, taking into account the characteristics of the traffic it serves. Figure 10 In one embodiment, for comparison with EDCA, traffic mapped to each AC is represented as traffic mapped to each STA, but when MLD maps traffic to STAs (links), for higher decomposition efficiency, it may attempt to map according to TID.

[0161] According to embodiments of the present invention, a TID belonging to a frame may exist. For example, signaling indicating a TID belonging to a frame may be included in the frame, and the signaling may be a TID subfield. More specifically, the signaling indicating a TID may be included in the MAC header of the frame. For example, the signaling indicating a TID may be included in the QoS control field. For example, the frame type may be a data frame or a QoS data frame. 802.11, to enhance QoS, displays a TID based on the traffic type in the TID subfield of the QoS control field present in the MAC frame. In this case, the TID represents the user priorities (UPs) or traffic stream identifier (TSID) included in the MSDU or fragment or A-MSDU in the frame body. The TID subfield consists of 4 bits and can represent a value from 0 to 15.

[0162] When the TID subfield represents a value from 0 to 7, it means that the value of the TID subfield is the value of the UPs for MSDU included in the frame body, and EDCA is used for the access policy and processed in the MAC entity using the AC parameter corresponding to the UP.

[0163] When the TID subfield represents a value of 8 to 15, it indicates that the value of the TID subfield is the TSID value of the MSDU included in the frame body, the MSDU being processed according to the UP indicated by the User Priority subfield of the TS Information field in the MAC entity in the TSPEC, and following the values ​​indicated by other parameters of the TSPEC.

[0164] At this time, the UP of TSID traffic can also be confirmed through the user priority field of TCLAS instead of TSPEC. Furthermore, the access policy applicable to MSDUs with values ​​of 8 to 15 in the TID subfield is indicated by the access policy of other subfields of the TS Info field, and can be interpreted as the access policy (Bit7, Bit8) of the TS Info field indicating EDCA when displayed as (1,0), and indicating HCCA when displayed as (1,0) or (1,1).

[0165] Furthermore, when mapping the TID corresponding to the TS to the link, the ADDTS request frame used when generating the TS can display the internal access class priority element, and can include the backup queue (AC queue) information used by the user priority and EDCA when requesting the transmission of the corresponding TS from the internal access priority field present in the element. In this case, MLD can consider processing the traffic with TID corresponding to the TS in the UP and queue information indicated by the internal access priority field.

[0166] Thus, since TID has the meaning of UPs corresponding to traffic, it is similar to Figure 10 In one embodiment, traffic corresponding to each AC is mapped to different STAs. Alternatively, an MLD can be used to map traffic for each TID to a different STA. This can be conceptually understood as TID-to-STA mapping or TID-to-link mapping, and in order to perform TID-to-link mapping, a protocol between communicating MLDs is necessary.

[0167] In other words, a specific MLD can send its own TID-to-link mapping plan signaling to other MLDs. MLDs receiving the TID-to-link mapping plan from a specific MLD can accept or reject the TID-to-link mapping plan from that specific MLD. In this case, if two interconnected MLDs do not have a separate TID-to-link mapping protocol, each MLD can transmit traffic through all links connected to the other MLD, regardless of the traffic's TID. This can be understood as all TIDs mapping to all links, which could be the implicit default TID-to-link mode between two MLDs initially establishing a connection.

[0168] The detailed rules to be followed when executing TID-to-link mapping may not be defined. However, when executing TID-to-link mapping, MLDs must map all TIDs to one or more links. According to embodiments of the present invention, frames with TIDs mapped to a link can be transmitted to that link. Alternatively, frames with TIDs not mapped to a link can not be transmitted to that link. Furthermore, the mapping between TIDs and links can be formed separately for each MLD. Additionally, the mapping between TIDs and links can be formed separately according to the transmission direction of the link. For example, the mapping between TIDs and links can exist for each uplink and downlink. Furthermore, in this invention, TID-to-link mapping can be a combination of TID-to-link, TID-to-link mapping, and mapping between TIDs and links. Furthermore, in this invention, TID-to-link mapping can also refer to mapping between ACs and links, mapping between user priorities and links, mapping between traffic levels and links, or mapping between traffic flows and links.

[0169] Furthermore, the aforementioned TID-to-link mapping can be implemented differently between interconnected MLDs. As an example, when MLD1 and MLD2 are connected via Link 1 and Link 2, MLD1 maps traffic with TID values ​​of 0 to 3 to Link 1, and MLD2 maps traffic with TID values ​​of 4 to 7 to Link 1.

[0170] Furthermore, the signaling for TID-to-link mapping can be implicitly formed. As an example, when MLD1 and MLD2 are connected via Link 1 and Link 2, MLD1 can map only traffic with TID values ​​from 0 to 3 to Link 1 without separately signaling to map the remaining TIDs to the corresponding Link. In this case, other traffic with TID values ​​other than 0 to 3 can be interpreted as being mapped to Link 2. That is, a TID not mapped to a specific Link in the TID-to-link mapping signaling can be interpreted as being mapped to another Link not separately indicated in the TID-to-link mapping signaling. In this case, the Link not separately indicated can be interpreted as a Link where all TIDs are mapped.

[0171] In addition, when the two MLDs establish an initial MLD connection, and when changes are needed during use, 1) when the MLD switches the STA of a special link to disassociation / disable according to the application policy (such as Power Save); 2) when the MLD determines that it is difficult to guarantee the QoS of traffic mapped to a special link, it can request the other MLD to change its own TID to link mapping settings.

[0172] In addition, a special MLD can request a change to the link mapping of the other MLD. For example, when an AP MLD maps traffic with TIDs 0 to 3 to Link 1 for traffic to be transmitted to a non-AP MLD, the non-AP MLD can request a change to map the link mapping of that traffic to another link other than Link 1 (e.g., Link 2).

[0173] Furthermore, when a TID-to-link mapping request executed by a specific MLD is rejected by the counterpart MLD, the specific MLD's request for the same TID-to-link configuration mapping can be restricted for a period of time. This is to prevent duplicate TID-to-link mapping requests and rejections, and the time limit for the same TID-to-link request after rejection can be indicated by the AP.

[0174] That is, after a special MLD requests a link mapping for a special TID through the TID to link mapping element of the request frame, if the other MLD rejects the requested mapping relationship through the request frame, the special MLD will be restricted from re-requesting the rejected mapping relationship through the request frame for a period of time.

[0175] Therefore, the AP MLD can use parameters from the BSS to signal time information related to the TID-to-link mapping request interval to its own BSS's STA. In this case, the restriction on the rejected TID-to-link mapping can apply to each rejected TID. In other words, when multiple TID and link mapping requests submitted at once are rejected for a specific TID, re-requesting the mapping of that specific TID for the rejected link may be restricted.

[0176] Figure 11 An embodiment of a TID-to-link mapping method for establishing a connection between an AP MLD and a non-AP MLD is shown.

[0177] In order to establish TID-to-link mapping rules between AP MLDs and non-AP MLDs, it is necessary to explicitly indicate which TID is mapped to which link.

[0178] According to embodiments of the present invention, there may be signaling indicating which TID is mapped to which link. For example, the signaling may be a TID-to-link mapping element. The TID-to-link mapping element may include a Link ID field. The Link ID field may include a value indicating the link mapped by the TID-to-link mapping element that includes the Link ID field.

[0179] Alternatively, the Link ID field may include a value indicating which link information is displayed in the TID information field corresponding to the Link ID field.

[0180] In addition, the TID-to-link mapping element may include a TID information field. The TID information field may include information about the mapped TID. For example, the TID information field may include information about the TID mapped to a link, which is the link indicated by the Link ID contained in the TID-to-link mapping element that includes the TID information field. For example, the TID information field may include one or more bits corresponding to each TID value. If a TID is mapped to a link, the bits corresponding to that TID can be set to a preset value (e.g., 1). Furthermore, when a TID is not mapped to a link, the bits corresponding to that TID can be set to a different preset value (e.g., 0).

[0181] Figure 11 (a) AP MLD can plan to transmit (0,1,2,3) traffic with TID 0 to 3 through AP1 used in Link1 in the traffic (MSDU) to be transmitted to non-AP MLD.

[0182] Therefore, AP MLD will use the Link ID field of the TID to Link mapping element (c) to indicate Link 1, and then use the TID information field to map non-AP MLD signaling TIDs 0 to 3 to Link 1. At this time, (c) the TID to Link mapping element is an element format used for example and can be easily understood to be used for the same purpose as elements in other structures.

[0183] After a non-AP MLD confirms each TID transmission link in the AP MLD plan through the TID-to-link mapping element, it can allow or deny this.

[0184] Figure 12(b) After the non-AP MLD confirms the TID-to-link mapping received from (a) AP MLD, it can be understood as agreeing to map traffic corresponding to TIDs 0 to 3 to Link 1 and traffic corresponding to TIDs 4 to 7 to Link 2. In this case, the TID-to-link mapping element transmitted by the AP MLD to the non-AP MLD can be composed of two Link ID and TID information subfields. At this time, the two Link ID subfields can indicate Link 1 and Link 2 respectively, and the two TID information subfields can be indicated by values ​​representing 0 to 3 and values ​​representing 4 to 7 respectively.

[0185] At this point, the TID information subfield consists of 8 bits, which can be understood as each bit corresponding to TID 0 to TID 7. That is, to indicate TID 0 to 3, the 8 bits of the TID information subfield can be displayed as 1111 0000, and to indicate TID 4 to 7, the 8 bits of the TID information subfield can be displayed as 0000 1111.

[0186] At this point, the TID information subfield consists of 8 bits, which can be understood as each bit corresponding to TID 0 to TID 15. That is, to indicate TID 0 to 3, the 16 bits of the TID information subfield can be displayed as 1111 0000 0000 0000, and to indicate TID 4 to 7, the 16 bits of the TID information subfield can be displayed as 0000 1111 0000 0000.

[0187] Alternatively, the TID information subfield can consist of two subfields: Min TID and Max TID. In this case, the Min TID subfield indicates the lowest TID value among the TIDs to be mapped to the corresponding link, while the Max TID subfield indicates the maximum TID to be mapped to the corresponding link. In this case, Min TID and Max TID can be represented using 3 bits or 4 bits, respectively.

[0188] As a 3-bit implementation, when the Min TID subfield of the TID information subfield represents 000 and the Max TID subfield represents 011, the TID indicated by the TID information subfield can be interpreted as 0 to 3. When the Min TID subfield represents 100 and the Max TID subfield represents 111, the TID indicated by the TID information subfield can be interpreted as 4 to 7.

[0189] As a 4-bit implementation, when the Min TID subfield of the TID information subfield represents 0000 and the Max TID subfield represents 0011, the TID indicated by the TID information subfield can be interpreted as 0 to 3. When the Min TID subfield represents 0100 and the Max TID subfield represents 0111, the TID indicated by the TID information subfield can be interpreted as 4 to 7.

[0190] exist Figure 11 After (a) AP MLD confirms the TID to link mapping received from (b) non-AP MLD, it can be understood as agreeing to the situation where traffic corresponding to TID 0 to 3 is mapped to Link 1, and traffic corresponding to TID 0 to 7 is mapped to Link 2.

[0191] In this scenario, (b) the non-AP MLD only shows that TIDs 0 to 3 are mapped to Link 1 via the TID-to-Link mapping element, without separately showing that TIDs 0 to 7 are mapped to Link 2. In other words, since (b) the non-AP MLD does not separately indicate the TIDs to be mapped to Link 2 in the TID-to-Link mapping element transmitted to (a) the AP MLD, (a) the AP MLD can implicitly interpret that all TIDs can be mapped to Link 2 where they are not indicated.

[0192] Using the TID-to-link mapping described above, an MLD can map traffic to be served to one or more STAs (Links) using the traffic's TID. If a TID mapped to a specific link corresponds to two or more EDCA ACs, the QoS STA (MLD) using that specific link will distinguish the ACs and provide services for the traffic of the mapped TID according to the EDCA mechanism. In other words, an MLD can use TID-to-link mapping to map a TID to each link, and each STA of the MLD can apply the EDCA mechanism to the traffic of the TID mapped to its own link.

[0193] As an example, if a specific MLD maps the traffic corresponding to AC_VO and the traffic corresponding to AC_BK to a specific link via TID-to-link mapping, then the STA operating on that specific link will prioritize serving the traffic corresponding to AC_VO over the traffic corresponding to AC_BK. In this case, if the STA operating on the specific link sets the sum of the CWmax and AIFSN parameters of AC_VO to be less than the AIFSN of AC_BK, then the STA operating on the specific link can consistently prioritize serving the traffic corresponding to AC_VO over the traffic corresponding to AC_BK.

[0194] In this way, MLDs can adjust and change the TIDs mapped to each link according to their application objectives, enhance QoS, or perform operations that take into account the performance characteristics of each link, and there is no separate definition of the rules to be followed when performing TID-to-link mapping. This means that, unlike the EDCA mechanism which provides UP to AC rules, MLDs can freely use TID-to-link mapping based on their application policies. However, all TIDs must be mapped to at least one link, and an MLD may not request a TID-to-link mapping from another MLD for at least one TID that is not mapped to any link. Therefore, when a TID mapping for at least one link is not implicitly formed, all TIDs must be explicitly mapped to at least one or more links.

[0195] Figure 12 An embodiment of a TID-to-link mapping method that can be established between AP MLDs and non-AP MLDs is shown.

[0196] Figure 12 (a) is an embodiment where both AP MLD and non-AP MLD use the default TID to link mapping, considering the scenarios where AP MLD and non-AP MLD use AP1 and AP2 respectively on Link 1 and Link 2, and AP STA1 and non-AP STA2 respectively. In this case, when AP MLD and non-AP are associated with MLD without a separate TID to link mapping request / acknowledgment, the same default TID to link mapping state as considered in this embodiment can be maintained.

[0197] Reference Figure 12 (a) confirms that the AP MLD maps not only TIDs but also TSIDs to all links, and that TSIDs are not individually mapped to links; therefore, the mapping to all links can be the default mapping state. In this case, if the MLD wants to change the mapping of TSIDs to a form other than the default mode (e.g., mapping TSID 9 only to Link 2), it can use the same method as TID-to-link mapping. The specific method of TSID-to-link mapping can be easily understood when considering the TID-to-link method, therefore its detailed description will be omitted.

[0198] <Quality-of-Service Management Frame (QMF) Policy>

[0199] As mentioned above, MLD uses TID-to-link mapping to enhance QoS, thus enabling service link differentiation that considers the traffic characteristics served by the MAC. This can be understood as similar to traditional Wi-Fi using the EDCA mechanism to differentiate ACs based on traffic characteristics; MLD treats each link as an access link (AL) and differentiates ALs based on traffic characteristics.

[0200] However, the traffic that Wi-Fi MAC needs to process includes not only MSDU requests to be processed at the upper layer, but also management frames containing information for using the BSS. In the case of these management frames, unlike each MSDU which has a TID, they do not have a separate TID.

[0201] Therefore, the QoS STA needs to determine the AC to use when transmitting QoS management frames. The traditional 802.11 standard provides a default QMF policy for QoS management frames so that the QoS STA can determine the AC to use when transmitting QoS management (hereinafter referred to as management frames) frames. In this case, the QMF policy may be modified by the QoS AP using the QoS BSS. According to one embodiment, there may be an AC corresponding to the management frame.

[0202] Furthermore, the Access Class (AC) corresponding to the management frame can be determined by the QMF policy. In this case, the AC corresponding to the management frame can be referred to as the QMF Access Class. Additionally, the type or QMF AC of the management frame can be determined based on the type, subtype, or class value corresponding to the management frame. Furthermore, services with an AC corresponding to the management frame, or services based on the AC access channel when transmitting management frames according to the QMF policy, can be referred to as QMF services. Moreover, frame transmission based on the QMF policy can be limited to situations where both the transmitting STA and the receiving STA support QMF.

[0203] Table 2 below shows some examples of the default QMF policy.

[0204] [Table 2]

[0205] Referring to Table 2, for (re)association requests / responses, AC_VO is set to the default AC. Therefore, when the QoS STA transmits an association request or a response association response, it uses the CW and AIFSN parameters of AC_VO for transmission. On the other hand, in the case of Timing Advertisement, if the default AC is set to AC_BE and the QoS AP does not separately change the QMF policy of the QoS BSS, the QoS STA uses the CW and AIFSN parameters of AC_BE for transmission when transmitting the timing advertisement.

[0206] Thus, in the default QMF policy, different QMF access categories are assigned according to the type of management frame because there are management frame types with low processing urgency even as management frames, and in order to prevent the services of other traffic and management frames from being delayed during the processing of management frames with low processing urgency.

[0207] As described above, management frames also need to distinguish ACs according to the information and functions they contain. Therefore, similar to differentiating AL according to TID through the TID-to-link mapping, MLD maps management frames to different links according to their types.

[0208] However, the default QMF policy of MLD can be set so that all QMFs can use all ACs. That is, the default QMF policy of MLD can set the QMF access category to AC_Any for all subtypes of management frames.

[0209] According to an embodiment of the present invention, when QMF service is permitted, the management frame can be transmitted based on the access category corresponding to the management frame. However, the access category may be limited to channel access. According to an embodiment of the present invention, when transmitting a management frame when QMF service is permitted, it is transmitted based on the access category corresponding to the management frame, but regardless of the TID-to-link mapping, it can be transmitted on any link. For example, even if the AC corresponding to the management frame is mapped to a link based on the TID-to-link mapping, the management frame can be transmitted on the link.

[0210] That is, in the case of general frames, they are transmitted on the link mapped to the assigned TID. However, in the case of management frames, since a TID may not be assigned, there is no special link for transmission. In this case, since a TID is not assigned to the management frame, there is no need to set a mapping relationship between the TID and the link. Therefore, the management frame can be transmitted regardless of the mapping between the TID and the link.

[0211] <QMF (quality-of-service management frame) to Link Mapping>

[0212] As the simplest method for performing QMF-to-link mapping, each management frame can be mapped to the link to which the traffic corresponding to the AC is mapped, based on the QMF access class assigned to each management frame (see Table 2). In other words, management frames can be transmitted based on TID-to-link mapping.

[0213] For example, when an AC (or TID) is mapped to a link, and the AC (or TID) corresponding to the management frame is that AC (or TID), the management frame can be transmitted from the link. Conversely, when an AC (or TID) is not mapped to a link, and the AC (or TID) corresponding to the management frame is that AC (or TID), the management frame cannot be transmitted on the link.

[0214] More specifically, if a specific MLD indicates that the TID corresponding to traffic of AC_VO is mapped to a specific link, then the associated request / response management frame assigned to AC_VO by the QMF access class can be mapped to the specific link. The QoS STA can change the AC used to process each management frame without adhering to the default QMF policy; correspondingly, by changing the AC assigned to each management frame, it is free to change the link to which each management frame is mapped.

[0215] Therefore, even for QMFs without TIDs, MLD can perform QMF-to-link mapping for each QMF in a manner similar to TID-to-link mapping.

[0216] However, in the case of special QMFs, such as general MSDUs, information may be exchanged not at the MLD level, but rather between each STA within the MLD. In this case, if the MLD only maps the special QMF to a specific link, there is a problem that STAs on other links that are not special links cannot transmit the special QMF.

[0217] In other words, in the case of QMF, regardless of the type of AC assigned to the QMF, there may be a QMF that must be able to be transmitted on all links. Therefore, MLD can indicate the QMF mapped by all links independently of the assigned AC.

[0218] In other words, in the case of management frames, no specific TID is assigned. Since no TID is assigned, the mapping between TIDs and links can be ignored. Therefore, regardless of the mapping between TIDs and links, management frames can be transmitted to all links. In this case, the link transmitting the management frame can be an enabled link that has established a mapping between TIDs and links. In this context, an enabled link is a link that has established a mapping relationship with at least one TID.

[0219] In this scenario, when management frames are transmitted only through an enabled link, there may be situations where management frames cannot be transmitted when the link is not enabled, except for broadcast management frames transmitted independently of the link. Therefore, in the case of special management frames, transmission is possible even without a enabled link.

[0220] Figure 13 An example is shown of a TID-to-link mapping element that indicates a QMF that can be transmitted independently of the link.

[0221] Reference Figure 13 When performing TID to link mapping, regardless of the AC assigned by the QMF policy, MLD can indicate the QMF that can be mapped to all links.

[0222] Specifically, information related to the management frame subtype can be indicated in the TID-to-link mapping element, and the management frame of the indicated subtype can be mapped to all links, regardless of the AC (or TID) assigned to the management frame.

[0223] like Figure 13 As shown, a TID-to-link mapping element can have a QMF support field corresponding to each Link ID. The QMF support field indicates whether all types of QMFs can be mapped in the Link indicated by the corresponding Link ID field. More specifically, when the QMF support field corresponding to a particular link is set to 1 (true), all types of QMFs can be mapped to the particular link, regardless of the QMF policy of each QMF.

[0224] Furthermore, the (QMF) management frame subtype may be displayed in the TID to link mapping element. In this case, the QMF subtype corresponding to the value indicated by the management frame subtype field is independent of the assigned AC and can be mapped to all links. For example, when the management frame subtype field is 0101 (probe response), the probe response frame, assigned / indicated by the QMF policy, is AC independent and can be mapped to all links.

[0225] In other words, the TID-to-link mapping element can include a QMF support field to indicate whether all QMFs are mapped to each link. Additionally, the TID-to-link mapping element can include a (QMF) management frame subtype to indicate whether a specific subtype of management frame can be mapped to all links. Alternatively, when transmitting QMFs, there may be signaling indicating whether transmission is based on TID-to-link mapping. That is, when transmitting QMFs on a specific link, there may be signaling indicating whether transmission can be determined based on TID-to-link mapping.

[0226] In other words, according to one embodiment, when the signaling indicates a preset value, QMF can be transmitted regardless of the TID-to-link mapping. That is, even if the AC corresponding to the QMF is not mapped to a link based on the TID-to-link mapping, it can still be transmitted on that link. In another embodiment, when the signaling displays a preset value, QMF can be transmitted based on the TID-to-link mapping. That is, when the AC corresponding to the QMF is mapped to a link based on the TID-to-link mapping, it can be transmitted on that link. Furthermore, if the AC corresponding to the QMF is not mapped to a link based on the TID-to-link mapping, it cannot be transmitted on that link.

[0227] However, when the MLD receives a request-response QMF (such as a probe request / response) via a special link, the QMF frame can be responded to via the special link, regardless of the MLD's QMF-to-link mapping strategy. In other words, when a request-type QMF frame is received on a special link, a response-type QMF frame can be responded to via the special link, regardless of the AC (Access Control Point). Furthermore, when a request-type QMF frame is received on a special link, a response-type QMF frame can be responded to via the special link, regardless of the QMF-to-link mapping.

[0228] Figure 14 An example of an MLD operation for establishing a QMF policy through a TID-to-link mapping is shown.

[0229] Figure 14 (a) is an example of a TID-to-link mapping element that can be generated to perform TID-to-link mapping on three links. In this case, if the MLD that generated this element is associated with more than 4 other MLDs, it is implicitly shown that the links not explicitly indicated by the link ID field of this element are using the default TID-to-link mapping, which can then be interpreted by the receiving MLD.

[0230] At this point, a special MLD is generated. Figure 14 As shown in (a), the TID is mapped to the link element and the other party's MLD is accepted. In this case, the special MLD can be generated by, for example... Figure 14 The method shown in (a) transmits traffic and QMF frames. For reference, Figure 14 (a_1), (a_2), and (a_3) of (a) represent the subfields of Link 1, Link 2, and Link 3, respectively, while (a_common) is inserted to represent the subfield that is commonly applied to all links.

[0231] Reference Figure 14For (b), MLD can use Link 1 to map and transmit traffic with TIDs 0 to 3. In this case, TIDs 0 to 3 can be the TIDs in the AC corresponding to AC_BK (UP 1, 2) and AC_BE (UP 0, 3). At this time, referring to Figure 14 For (a_1) of (a), the QMF support of Link 1 is indicated as 1 (true). Therefore, MLD, regardless of the AC assigned to each QMF, can transmit (map) all subtypes of QMF through Link 1.

[0232] As Figure 14 Shown in (b), MLD, similar to Link 1, can transmit (map) traffic with TIDs 0 to 3 through Link 2. However, the QMF support field corresponding to Link 2 (refer to Figure 16 For (a_2) of (a)) is indicated as 0. Therefore, only the QMFs of the ACs assigned the same TIDs as those mapped to Link 2 can be mapped and transmitted to Link 2. However, since 1111 is indicated by the (QMF) management frame subtype field ( Figure 16 For (a_common) of (a)), MLD can transmit (map) the QMF with the management frame subtype field of 1111 (1111) through Link 2. At this time, in order for the STA of Link 2 to transmit the QMF (1111), the AC assigned (indicated by the QMF policy) to the QMF (1111) can be applied to attempt channel access.

[0233] Traffic with TIDs 4 to 7 can be transmitted (mapped) to Link 3 of MLD. At this time, TIDs 4 to 7 can be the traffic mapped to AC_VI and AC_VO. At this time, the QMF support field corresponding to Link 3 ( Figure 16 For (a_3) of (a)) is indicated as 0. Therefore, MLD can only transmit or map the QMFs of AC_VI / AC_VO through Link 3. However, since 1111 is indicated by the QMF management frame subtype field, MLD can transmit (map) the QMF with the management frame subtype field of 1111 (1111) through Link 3. At this time, in order for the STA of Link 3 to transmit the QMF (1111), the AC assigned (indicated by the QMF policy) to the QMF (1111) can be applied to attempt channel access.

[0234] <TID (traffic identifier) to Link Mapping Negotiation>

[0235] According to one embodiment of the present invention described above, MLDs can enhance QoS by performing TID-to-link mapping to map each TID to a different link. The following embodiment of the present invention provides specific signaling methods and negotiation process methods for performing TID-to-link mapping between MLDs.

[0236] For reference, in the accompanying drawings of the various embodiments provided below, the immediate Ack frame may be omitted for the sake of brevity. For example, an MLD that receives a TID to Link Mapping Request frame may transmit an immediate Ack frame (response after SIFS) as a response, and this may be omitted for brevity.

[0237] The MLD (AP MLD or non-AP MLD) requesting TID-to-link mapping uses the TID-to-link mapping element to indicate a specific TID and a specific Link, thereby requesting that the indicated TID be mapped to the indicated Link. In this case, the TID-to-link mapping element can also be used to indicate multiple TIDs combined with multiple Link groups.

[0238] As an example, a single TID-to-link mapping element can indicate that TID groups #1, #2, and #3 correspond to Link groups #1, #2, and #3, respectively. In this case, if TID group #1 is indicated to correspond to Link group #1, it can be understood as an attempt to map the TID corresponding to TID group #1 to the link corresponding to Link group #1. At this point, a TID-to-link mapping element including the TIDs and Link information to be mapped can be transmitted via a TID-to-link mapping request frame (enclosed within the TID-to-link mapping request frame). The MLD transmitting the TID-to-link mapping request frame can be called an Initiating MLD or a Requesting MLD.

[0239] As described above, an MLD that receives a TID-to-link mapping element (TID-to-link mapping request frame) containing indication information for the TID and Link can confirm the TID-Link mapping information required by the MLD that transmitted the TID-to-link mapping request frame. Subsequently, the MLD that received the TID-to-link mapping request frame can respond with a TID-to-link mapping response frame in order to allow (accepts / adopts) or refuse (refuses / rejects / denies) the mapping between the TID and Link that initiated the MLD request. Since the MLD receiving the request frame must respond with the TID-to-link mapping response frame, this can be called a responding MLD.

[0240] To allow mapping between TID-Links from the initiating MLD request, the responding MLD can respond without including a TID-link mapping frame in its own response TID-link mapping response frame. In other words, if the received TID-link mapping response frame, which is a response to its own transmitted TID-link mapping request frame, does not contain a TID-link mapping element, then the initiating MLD can recognize that the mapping between the requested TID-Links has been allowed by the responding MLD.

[0241] In other words, when the transmission / reception of a response frame that does not contain a TID-to-link mapping element is completed, it can be understood that a new TID-to-link mapping has been negotiated between the two MLDs transmitting / receiving the response frame. At this time, the two MLDs may have a grace period to communicate based on the newly negotiated TID-to-link mapping.

[0242] At this point, the grace period can be used to manage the transmission queues of STAs (STAs) that are connected to each link in each MLD. More specifically, after the TID-to-link mapping negotiation is completed, each MLD has a grace period for managing the transmission queues of the STAs corresponding to each Link, based on the TID-to-link mapping status of the protocol. That is, after the grace period corresponding to the predetermined time has elapsed, the two MLDs that have completed the TID-to-link mapping communicate according to the TID-to-link mapping status of the protocol. At this time, communicating according to the TID-to-link mapping status means that only traffic (frames, etc.) mapped to the corresponding link's TID can be transmitted / received on a particular link.

[0243] On the other hand, when the responding MLD attempts to reject the mapping between the TID and the link from the MLD request, it can respond by including a TID-to-link mapping element in its own response frame. In this case, the TID-to-link mapping element included in the response frame can indicate a different TID and Link than the TID-to-link mapping element included in the request frame. For example, the TID-to-link mapping element included in the request frame can indicate that TID 0 corresponds to Link 1. In this case, if the responding MLD indicates TID 0 and Link 2 in the corresponding TID-to-link mapping element included in its response frame, the initiating MLD of the transmission request frame can recognize that its own proposal to map TID 0 to Link 1 has been rejected. Furthermore, the initiating MLD can recognize that the responding MLD needs to map TID 0 to Link 2 by confirming that TID 0 corresponds to Link 2 in the response frame from the responding MLD.

[0244] In other words, if the initiating MLD receives a response frame to the responding MLD that includes a TID-to-link mapping element, then when the initiating MLD configures and sends a response MLD (re)transmission request frame, it can similarly indicate the mapping information between the TID-Links indicated in the received response frame.

[0245] Furthermore, the response MLD can receive only a portion of the mappings between TID-Links indicated (requested) by the initiating MLD via the TID-to-link mapping element. For example, the initiating MLD can request TID 0 to be mapped to Link 1 by indicating that TID 0 corresponds to Link 1, and simultaneously request TID 1 to be mapped to Link 2 by indicating that TID 1 corresponds to Link 2. In this case, the response MLD can only allow one of the two mapping requests requested by the initiating MLD (TID 0 to Link 1, TID 1 to Link 2). In this scenario, the response MLD can allow TID-Link mapping requests associated with specific TIDs by indicating only the TIDs to be allowed, excluding the specific TID, in the TID-to-link mapping element contained in the response frame. In other words, if the list of TID-Link mappings (which can be fields or subfields) indicated by the initiating MLD contains TID-Link mappings to be allowed (included in the TID-to-link mapping element of the request frame), the response MLD can implicitly indicate the allow intention by not indicating the corresponding TID (the TID to be allowed) in the response frame. Therefore, if the TID indicated in the request frame of the initiating MLD contains a TID that is not indicated in the response frame of the responding MLD (no reverse proposal), the initiating MLD can recognize (interpret) that the TID-Link mapping request for that TID is allowed.

[0246] By including TID-to-link mapping elements in beacon frames, AP MLDs can help non-AP STAs (MLDs) receiving beacon frames identify their preferred TID-Link mapping states. In this case, when a non-AP STA MLD transmits an association request frame to the corresponding AP MLD, it can request TID-to-link mapping negotiation from the TID-to-link mapping elements. At this point, the non-AP STA MLD, considering the AP's preferred TID-Link mapping state indicated by the beacon frame, can set the TID-to-link mapping elements to be included in its own transmitted association request frames. In this case, AP MLDs that include TID-to-link mapping elements in their beacon frames can be restricted to AP MLDs that support TID-to-link mapping negotiation.

[0247] TID-to-link mapping elements can be included in (re)association request / response frames or can be transmitted via TID-to-link mapping request / response frames. In this case, the TID-to-link mapping elements included in either type of response frame can be included to propose a preferred TID-Link mapping to the MLD in the transmission request frame. Alternatively, a response frame (unsolicited response frame) transmitted without receiving a request frame including a TID-to-link mapping element can be transmitted to propose (indicate) a preferred TID-to-link mapping state to the MLD of a single-destination device as the response frame.

[0248] Figure 15 An example of the format of TID to link mapping elements is shown.

[0249] Since the TID-to-link mapping element needs to indicate TID-Link pairs, it can be configured to include subfields indicating the TID and subfields indicating the Link. In this case, the subfields indicating the TID and Link can be used to indicate a single TID and Link, or they can be used to indicate a TID group and a Link group. The methods for indicating TID and Link, or TID group and Link group, can then be similar to... Figure 11 One embodiment describes a TID indication method using an 8-bit TID information field.

[0250] That is, in order to indicate that the Link group can use an 8-bit link information field, each bit of the link information field can be used to indicate whether the link corresponding to each index corresponds to the indicated TID. For example, when the TID information field is indicated as 1111 0000 and the link information field is indicated as 1100 0000 in a pair of TID to link mapping elements, it can be understood that TID 0 to TID 3 proposals / reverse proposals are mapped to Link 1 (0) to Link 2 (1).

[0251] Reference Figure 15 (a) A TID to link mapping element may have multiple TID to link mapping information fields (see [reference]). Figure 15 The configuration of (c) means that multiple TID and link pairs can be proposed / reverse proposed using a single TID-to-link mapping element. In other words, the TID-to-link mapping element, in order to indicate the mapping between one or more TIDs and one or more links, can include mapping information representing each mapping relationship. In this case, multiple TIDs can be mapped to one link.

[0252] In other words, a TID-to-link mapping element can indicate different TIDs and links in each of the multiple TID-to-link mapping information fields. However, within a single TID-to-link mapping element, a specific TID cannot be indicated in more than one TID-to-link mapping information field.

[0253] In other words, there may be a limitation that each TID is indicated only once (or less) within a TID-to-link mapping element. For example, if TID 0 is indicated in the TID information subfield of the first TID-to-link mapping information field of a TID-to-link mapping element, then TID 0 may not be indicated in the remaining TID-to-link mapping information fields included in the corresponding element. In this case, indicating TID 0 can be either TID 0 indicated alone, or a group of TIDs including TID 0 (e.g., TID 0 to TID 3).

[0254] like Figure 15 As shown, the format of a TID-to-link mapping element can vary depending on the number of TID-to-link mapping information fields included. Therefore, a TID-to-link mapping element can include fields indicating information related to its own length.

[0255] exist Figure 15 In (a), the TID-to-link mapping control field can be indicated before the TID-to-link mapping information field to indicate information related to the length of the TID-to-link mapping information field. In this case, the length-related information can be the TID-to-link mapping information field included within the TID-to-link mapping information field. Figure 15 The number of (c) and the length (size) of each TID to link mapping information field. That is, the information for the length can be related to the number of one or more TIDs mapped to one or more links.

[0256] Reference Figure 15 (b) The TID-to-link mapping control field may include a TID-to-link mapping information size subfield and a link bitmap size subfield. The TID-to-link mapping information size subfield may indicate information related to the length of the TID-to-link mapping information fields included in the TID-to-link mapping element. For example, the TID-to-link mapping information size subfield may indicate the number of TID-to-link mapping information fields included in the TID-to-link mapping element. Alternatively, the TID-to-link mapping information size subfield may indicate the size (octet units, etc.) of the TID-to-link mapping information fields included in the TID-to-link mapping element.

[0257] The Link Bitmap Size subfield can be used to indicate the size of the link information subfield contained in each TID to Link Mapping Information field. The reason for needing the Link Bitmap Size subfield is that, unlike the fixed number of TIDs (TID 0 to TID 7), the number of Links in an MLD is variable. Therefore, the Link Bitmap Size subfield can indicate a value related to the size of the link information subfield included in the TID to Link Mapping Information field. For example, a 4-bit Link Bitmap Size subfield can indicate a link information subfield size from 1 bit (Link Bitmap Size = 0000) to 16 bits (Link Bitmap Size = 1111). Alternatively, a 1-bit Link Bitmap Size subfield can indicate one of the set sizes of the link information subfield. For example, a Link Bitmap Size subfield displaying as 0 indicates a link information subfield size of 8 bits, and a Link Bitmap Size subfield displaying as 1 indicates a link information subfield size of 16 bits.

[0258] Furthermore, as mentioned above, the TID-to-link mapping negotiation can be formed independently for the DL and UL directions (see reference). Figure 11 Therefore, TID-to-link mapping negotiation performed between MLDs via TID-to-link mapping elements can also be performed simultaneously in both the DL and UL directions. That is, information for both DL and UL TID-to-link mapping negotiation can be indicated in a single TID-to-link mapping element. With this in mind, the TID-to-link mapping information field can include both DL and UL TID-to-link mapping information fields.

[0259] Furthermore, to separately indicate the size of the DL TID-to-link mapping information field and the UL TID-to-link mapping information field, the TID-to-link mapping information size subfield can consist of two types of TID-to-link mapping information size subfields (DL TID-to-link mapping information size subfield and UL TID-to-link mapping information size subfield). However, if the information for DL ​​and UL is not separately indicated in the TID-to-link mapping element, it can be either the transmission of an MLD that includes a request frame containing the TID-to-link mapping element or unidirectional TID-to-link mapping information applicable to the receiving direction.

[0260] Simultaneously, there may be cases where each TID is indicated more than once within the TID-to-link mapping element. For example, in the first of the two TID-to-link mapping information fields contained in the TID-to-link mapping element of the request frame, the TID group containing TID 0 is mapped to Link 1. In the second of the second TID-to-link mapping information field, other TID groups containing TID 0 may again be indicated to be mapped to Link 2. In this case, the MLD receiving this (response MLD) can interpret that TID 0 is mapped to both Link 1 indicated by the first TID-to-link mapping information field and Link 2 indicated by the second TID-to-link mapping information field. Therefore, in this case, by responding with a response frame that does not include a TID-to-link mapping element, the response MLD can complete the TID-to-link mapping negotiation by mapping TID 0 to both Link 1 and Link 2.

[0261] <Methods for negotiating TID to link mapping (propose / allow / reject (reverse proposal)>

[0262] As described above, TID-to-link mapping negotiation can be performed between MLDs using TID-to-link mapping elements. The initiating MLD can use the TID-to-link mapping element contained in a request frame (TID-to-link mapping request frame or (re)association request frame) to indicate the TID-Link mapping it wishes to propose (prefer). After receiving the request frame from the initiating MLD, the responding MLD can determine whether to allow the TID-Link mapping indicated by the TID-to-link mapping element. Both the responding MLD and the initiating MLD can use TID-to-link mapping request frames, TID-to-link mapping response frames, TID-to-link mapping dismantling frames, etc., to perform TID-to-link mapping negotiation.

[0263] TID-to-link mapping request / response / teardown frames can be in the same frame format as TID-to-link mapping action frames. That is, the value of the TID-to-link mapping action frame is indicated in the category field of the action field, and the value used to distinguish TID-to-link mapping request frames, TID-to-link mapping response frames, and TID-to-link mapping teardown frames is indicated in the action details field. For example, a TID-to-link mapping action frame can be indicated as a category value between 32 and 125 reserved in 11ax (example: 32). In this case, TID-to-link mapping request / response / teardown frames can be distinguished by being indicated as 0, 1, or 2 respectively in the 1 octet following the category field. In other words, if the value of the action frame's category field is indicated as 32 and the next octet of the category field indicates 0 (0000 0000), then the corresponding action frame can be a TID-to-link mapping request frame.

[0264] If the responding MLD rejects all or part of the TID-Link mapping method proposed by the initiating MLD, it includes the TID-to-link mapping element in the response frame (TID-to-link mapping response frame, (re)association response frame), thus rejecting the TID-Link mapping proposed by the initiating MLD. In other words, when the TID-to-link mapping element is included in the response frame and is responded to, it can be understood that the TID-to-link mapping negotiation between the initiating MLD and the responding MLD is not complete. At this time, the TID-to-link mapping information field in the TID-to-link mapping element included in the response frame can indicate the TID-Link mapping information proposed by the responding MLD in the reverse proposal to the initiating MLD. For example, if the initiating MLD proposes (instructions / requests) to map TID 0 to Link 1 (via a request frame), and the responding MLD indicates via a request frame to map TID 0 to Link 2, then the initiating MLD can interpret the responding MLD's (reverse) proposal to map TID 0 to Link 2.

[0265] Furthermore, in the TID-Link mapping from the initiating MLD proposal (request), the responding MLD only indicates (reverse proposes) a portion of the TID-Link mapping via the response frame, thus allowing link mapping requests for all TIDs other than the indicated TID (indicated (proposed) via the request frame). In other words, it can be understood that the responding MLD's TID-Link mapping for the initiating MLD for TIDs not indicated via the response frame is permitted by the responding MLD. Therefore, after the initiating MLD indicates a link mapping for a specific TID in the TID-to-link mapping element of the request frame, if the responding frame's TID-to-link mapping element does not indicate the specific TID, it can be interpreted that a link mapping request for the specific TID is permitted by the responding MLD.

[0266] As described above, the response MLD does not include mapping information related to the mapping relationship between TIDs in the TID-to-link mapping element contained in the response frame, thus implicitly allowing the initiating MLD to request (or propose) the mapping relationship between TIDs and links via the request frame. Similarly, the initiating MLD does not include mapping information for the mapping relationship between some TIDs in the TID-to-link mapping element contained in the request frame, thereby implicitly proposing the mapping relationship between links with some TIDs to the response MLD.

[0267] When an MLD initiates a request frame to set up a mapping transmission between the response MLD, TID, and link, it excludes the mapping information of some TIDs among the multiple TIDs used for link mapping from the TID-to-link mapping element of the request frame. This implicitly indicates the mapping relationship of the partially omitted TIDs to the response MLD. In other words, if the request frame lacks mapping information about the mapping relationship between a specific TID and a link, the mapping relationship between the specific TID and the link can be implicitly indicated (or proposed).

[0268] In this case, the implicit proposal could be: 1) not to change the previously set mapping relationship and keep it valid, or 2) the mapping relationship between TID and link could be the default mapping relationship.

[0269] In this case, the default mapping relationship could be a mapping relationship where all links are mapped to one TID.

[0270] Specifically, an implicit proposal can be a proposal to map a TID not indicated in the TID-to-link mapping element to all links. That is, if the initiating MLD does not indicate a specific TID in the TID-to-link mapping element contained in the request frame, the specific TID can be (implicitly) indicated / requested to be mapped to all links.

[0271] Alternatively, an implicit proposal could be to propose a TID not indicated in the TID-to-link mapping element as maintaining the link mapping state for the previous corresponding TID. In other words, if the initiating MLD does not indicate a specific TID in the TID-to-link mapping element contained in the request frame, the specific TID (implicitly) indicates / requests to maintain the established TID-Link mapping state before transmitting a request frame containing the corresponding TID-to-link mapping element.

[0272] In other words, when a TID-Link mapping requested in a previously transmitted request frame is allowed for a specific TID, the initiating MLD does not indicate information about the specific TID in the next transmitted request frame. Therefore, the link mapping state that is already allowed for the specific TID can be maintained effectively without changing it.

[0273] Alternatively, if a TID-to-link mapping mode (including the default TID-to-link mapping mode) has been agreed upon and you do not wish to change the link mapping state of a specific TID, you can initiate an MLD request frame without indicating information about the specific TID, thereby maintaining the link mapping state of the specific TID.

[0274] At this point, the state of having a completed TID-to-link mapping mode can be either the state where the default TID-to-link mapping mode is applied between the two MLDs after the association is executed, or the state where the most recent TID-to-link mapping response frame transmitted / received between the MLDs does not include a TID-to-link mapping element.

[0275] On the other hand, if the responding MLD wants to allow all TID-Link mappings proposed (explicitly / implicitly) from the initiating MLD, then after receiving a TID-to-link mapping request frame from the initiating MLD, the responding MLD can respond with a TID-to-link mapping request frame that does not include a TID-to-link mapping element. In other words, the responding MLD does not perform a reverse proposal of TID-Link mapping via the response frame, thus allowing TID-to-link mappings indicated (proposed) by the initiating MLD. When the responding MLD receives a TID-to-link mapping response frame that does not include a TID-to-link mapping element, the initiating MLD can confirm that the TID-to-link mapping negotiation has been completed. Furthermore, based on the time point at which the TID-to-link mapping negotiation is completed, TID-Link mappings allowed by the responding MLD can be applied.

[0276] The above-described TID-to-link mapping negotiation proposal / allow / reject (reverse proposal) methods can be applied to the TIDs of DL and UL respectively, or to all TIDs of DL or UL at once. For example, when the initiating MLD does not indicate the TID for DL ​​through the TID-to-link mapping element (when the DL TID-to-link mapping information size indication is 0), the initiating MLD can implicitly propose to maintain the TID-Link mapping state for DL ​​as the agreed state. Alternatively, in order to change the TID-to-link mapping state for DL ​​to the default TID-to-link mapping state, the initiating MLD can not indicate the TID for DL.

[0277] In other words, when the MLD initiator only indicates the TID for the UL in the TID-to-link mapping element of the request frame, the MLD response can be interpreted as the initiator requesting that the TID-to-link mapping state for the UL be maintained as before. Alternatively, the MLD response can be interpreted as the initiator requesting that the TID-to-link mapping state for the DL be changed to the default TID-to-link mapping state.

[0278] Similarly, if the response MLD does not indicate all TIDs for DL ​​or UL in the response frame (when the size of the DL or UL TID to link mapping information is 0), then the unindicated DL or UL is interpreted by the initiating MLD as allowing all TID to link mappings proposed by the initiating MLD.

[0279] As described above, once the TID-to-link mapping negotiation process between the initiating MLD and the responding MLD is completed, the two MLDs will execute the link usage according to the TID-to-link mapping state completed by the protocol within a certain period of time. In other words, after the TID-to-link mapping negotiation process is completed, when the two MLDs perform transmissions themselves, they can only handle traffic mapped to the corresponding TID of the corresponding link and direction (DL / UL).

[0280] Furthermore, when the TID-to-link mapping between two MLDs is deactivated, i.e., when switching back to the default TID-to-link mapping mode, both MLDs will process traffic for all TIDs on all links for a certain period of time. For example, an MLD that has switched to the default TID-to-link mapping mode will remain able to perform immediate BA frame responses for all TIDs on all links after a certain period of time. In this case, "all TIDs" may simply refer to the TIDs that establish a BA session between the two MLDs. That is, when a mapping relationship is formed between TIDs and links, the MLDs can transmit / receive frames and corresponding BAs with each other through the formed mapping relationship.

[0281] Figure 16 The TID to link mapping process according to an embodiment of the present invention is illustrated.

[0282] Reference Figure 15 (a) AP MLD and non-AP MLD maintain the default TID to link mapping state. AP MLD and non-AP MLD are associated through two links (Link 1 and Link 2), and all TIDs (including TID 0 to TID 7 or TSID) are mapped to the state of said two links.

[0283] In order to perform AP MLD and TID to link mapping negotiation, such as Figure 16As shown in (b), the non-AP MLD can transmit a TID-to-link mapping request frame to the AP MLD. In this case, in the request frame transmitted via STA1, the non-AP MLD does not indicate the TIDs of the DL, but indicates that UL TIDs 0 to 3 be mapped to Link 1, and may indicate that UL TIDs 4 to 7 be mapped to Link 2. In order to indicate that TIDs 0 to 3 be mapped to Link 1, the non-AP MLD indicates TIDs 0 to 3 in the TID information subfield of the first UL TID-to-link mapping information field, and may indicate Link 1 in the corresponding link information subfield of the UL TID-to-link mapping information field. Similarly, to indicate that TIDs 4 to 7 be mapped to Link 2, the non-AP MLD indicates TIDs 4 to 7 in the TID information subfield of the second UL TID-to-link mapping information field, and may indicate Link 2 in the corresponding link information subfield of the UL TID-to-link mapping information field.

[0284] After receiving a TID-to-link mapping request frame from STA1 of a non-AP MLD, the AP MLD maintains the default TID-to-link mapping state for the DL's TIDs by including the TID-to-link mapping element in the received frame. It can also identify UL TIDs 0 to 3 that wish to be mapped to Link 1, and UL TIDs 4 to 7 that wish to be mapped to Link 2. If the AP MLD wishes to allow TID-to-link mappings indicated (requested) by the non-AP MLD, then... Figure 18 As shown in (b), a TID-to-link mapping response frame that does not include a TID-to-link mapping element can be responded to.

[0285] A non-AP MLD receiving a TID-to-link mapping response frame that does not include the TID-to-link mapping element from an AP MLD can recognize that the TID-to-link mapping negotiation has been completed. Thereafter, the following applies between the AP MLD and non-AP MLD: Figure 16 As shown in (c), the TID to link mapping status means that the non-AP MLD can only transmit traffic for TID 0 to TID 3 to UL via Link 1, and can only transmit traffic for TID 4 to TID 7 to UL via Link 2.

[0286] Figure 17 An example is shown in the TLD and link mapping that initiates the MLD indication (or proposal), where the responding MLD selectively responds to a subset of TIDs.

[0287] Reference Figure 17In order to map TID 0 to TID 3 to Link 1 and TID 4 to TID 7 to Link 2 via TID to Link Mapping Request Frame #1, an MLD (Medium-Level Distributed Decision) is initiated via a TID to Link Mapping Element Indication (Proposal). At this point, the MLD response allows the proposal to map TID 0 to TID 3 to Link 1, but may refuse to map TID 4 to TID 7 to Link 2.

[0288] In this scenario, the responding MLD, in response to the TID-to-link mapping request frame #1 received from the initiating MLD, transmits the TID-to-link mapping request frame #1, which includes the TID-to-link mapping elements, to the initiating MLD. At this time, when configuring the TID-to-link mapping elements, the responding MLD indicates (reverse proposal) that TID 4 to TID 5 are mapped to Link 2, and TID 6 to TID 7 are mapped to Link 3, thereby allowing Link 1 mapping for TID 0 to TID 3, and indicating that Link 2 mapping for TID 4 to TID 7 is rejected.

[0289] Upon receiving a TID-to-link mapping response frame #1 from the responding MLD, the initiating MLD considers the TID-Link mapping state (TID 4 ~ 5 = Link 2, TID 6 ~ 7 = Link 3) indicated by the responding MLD in the TID-to-link mapping response frame #1 and reconfigures the TID-to-link mapping request frame #2. At this point, the initiating MLD considers the TID-to-link mapping state proposed in reverse by the responding MLD and can transmit the TID-to-link mapping request frame #2, which indicates that TID 4 to TID 5 are mapped to Link 2 and TID 6 to TID 7 are mapped to Link 3 in the TID-to-link mapping elements. To allow the TID-Link mapping state indicated in the TID-to-link mapping request frame #2 received from the initiating MLD, the responding MLD responds with a TID-to-link mapping request frame #2 that does not include TID-to-link mapping elements, thus ending the TID-to-link mapping negotiation process.

[0290] At this time, the TID-to-link mapping state established (by the protocol) between the initiating MLD and the responding MLD can be the state merged from the TID-Link mapping states allowed by the TID-to-link mapping response frame #1 (TID 0 to 3 = Link 1) and the TID-to-link mapping response frame #2 (TID 4 to 5 = Link 2, TID 6 to 7 = Link 3). If in the TID-to-link mapping response frame #2, the initiating MLD re-indicates (proposes) a special TID (link mapping for the special TID) allowed by the TID-to-link mapping response frame #1, then the link mapping state of the special TID finally established (by the protocol) through the TID-to-link mapping response frame #2 that does not contain the TID-to-link mapping element can be the link mapping state of the special TID indicated in the TID-to-link mapping request frame #2.

[0291] <Restrictions on TID-to-Link Mapping Negotiation>

[0292] MLD may support or not support TID-to-link mapping negotiation according to its capability. For example, an MLD for which dot11TIDtoLinkMappingActivated is not indicated as true may be an MLD that does not support TID-to-link mapping negotiation. Therefore, before initiating TID-to-link mapping negotiation, the initiating MLD may need to confirm whether the responding MLD supports TID-to-link mapping negotiation. That is, the initiating MLD only transmits the TID-to-link mapping request frame to an MLD for which dot11TIDtoLinkMappingActivated is indicated as true.

[0293] In addition, even for an MLD that supports TID-to-link mapping negotiation, there may be a limit to the number of Link groups for which the MLD supports TID-to-link mapping. For example, an MLD that can manage the links of TIDs differentiated by TID-to-link mapping for 4 links may not support TID-to-link mapping negotiation for more than 4 links. Therefore, when configuring the TID-to-link mapping request frame for TID-to-link mapping negotiation, the initiating MLD configures the request frame considering the number of Link groups supported by the responding MLD. In addition, since the initiating MLD can attempt TID-to-link mapping negotiation for both the DL / UL directions, when configuring the TID-to-link mapping request frame, not only the number of Link groups supported by the responding MLD but also the number of Link groups it can support itself need to be considered.

[0294] Similarly, when the MLD responds to the link mapping request frame after receiving the TID from the initiating MLD, it transmits the TID to the link mapping response frame (in reverse) to propose TID-Link mapping, and configures the response frame considering the number of Link groups it can support and the number of Link groups the initiating MLD can support.

[0295] Therefore, in order to negotiate TID-to-link mappings between MLDs, it is necessary to identify the number of link groups that can support each other. For this purpose, a TID-to-link mapping negotiation support subfield can be indicated in the EHT MAC capability information field. The TID-to-link mapping negotiation support subfield can indicate a value related to the maximum number of link groups that it can manage through TID-to-link mapping negotiation. If a particular MLD does not support TID-to-link mapping negotiation at all (dot11TIDtoLinkMappingActivated = false), then the particular MLD can indicate 0 in the TID-to-link mapping negotiation support subfield. On the other hand, an MLD that can manage 4 link groups through TID-to-link mapping may need to indicate a value implying 4 in the TID-to-link mapping negotiation support subfield.

[0296] In summary, when each MLD proposes / reverses a TID-Link mapping status to another MLD via its own transmitted TID-to-link mapping request / response frame, it considers the maximum number of Link groups it can support and the maximum number of Link groups of the other MLD confirmed by the TID-to-link mapping support subfield when performing TID-Link mapping. That is, the MLD initiating the request frame cannot indicate more than the minimum number of Link groups (the number of Link groups it supports plus the number of Link groups supported by the responding MLD) through the TID-to-link mapping element (explicitly / implicitly) in the request frame. Similarly, the MLD responding to the response frame cannot indicate (reverse propose) more than the minimum number of Link groups (the number of Link groups it supports plus the number of Link groups supported by the initiating MLD) through the TID-to-link mapping element (explicitly / implicitly) in the request frame.

[0297] Furthermore, when a TID-Link mapping for a specific TID is rejected by the response MLD (reverse proposal), the initiating MLD cannot re-request the same link mapping that was rejected within a certain period of time. In this case, the certain period of time can be a value determined by parameters indicated by the AP MLD. In this case, the certain period of time can be the time from receiving an unindicated response frame from the response MLD. In this case, the certain period of time can refer to the lifecycle.

[0298] For example, if the initiating MLD maps TID 0 to Link 1 via a TID-to-Link Mapping Request Frame (proposal / request), and then receives a response MLD (reverse proposal) mapping TID 0 to Link 2, the initiating MLD must not execute a request to map TID 0 to Link 1 for a certain period (either a pre-set time or a time indicated by the AP MLD). This is likely to prevent wasted frequency resources and network congestion caused by repeated TID-to-Link Mapping Request / Response Frame exchanges. However, if the proposal to map TID 0 to Link 3 is never rejected, the initiating MLD might execute a new request to map TID 0 to Link 3 without following the response MLD's proposal.

[0299]

[0300] The aforementioned TID-to-link mapping negotiation process involves the initiating MLD proposing a mapping between TIDs and links, and the responding MLD allowing or rejecting the mapping state proposed by the initiating MLD. In this case, the responding MLD might only allow proposals for a subset of TIDs based on the TID-Link mapping state proposed by the initiating MLD, and reject proposals for the remaining TIDs. The responding MLD can then indicate (a reverse proposal) a preferred link mapping state for the TIDs whose proposals were rejected. The starting point for completing the TID-to-link mapping negotiation between the initiating MLD and the responding MLD is limited to when the responding MLD responds with a TID-to-link mapping response frame that does not include TID-to-link mapping elements.

[0301] Considering the TID-to-link mapping negotiation process described above, even if the initiating MLD, upon receiving the reverse proposal TID-Link mapping state from the responding MLD, allows the (reverse) proposal from the responding MLD, there is an inefficiency in retransmitting the TID-to-link mapping request frame. That is, in order to allow the reverse proposal TID-Link mapping state received from the responding MLD, the initiating MLD needs to retransmit the same TID-to-link mapping element that indicates the acceptance of the reverse proposal from the TID-to-link mapping element. Similarly, the responding MLD re-receives the same TID-Link mapping proposal as its own reverse proposal from the initiating MLD and re-responds with a TID-to-link mapping response frame that does not contain a TID-to-link mapping element, thus completing the TID-to-link mapping negotiation process. In this case, the precise starting point for the completion of the TID-to-link mapping negotiation process can be the starting point of executing an Ack response on the TID-to-link mapping response frame.

[0302] Thus, even if the initiating MLD has the intention to follow the TID-Link mapping state proposed in reverse from the responding MLD, initiating an MLD retransmission request frame, and the responding MLD also needs to retransmit the response frame, the retransmission request frame and response frame may be a TID-to-link mapping negotiation process that induces unnecessary overhead.

[0303] Therefore, it is possible to consider initiating a TID-to-link mapping negotiation process that allows the TID-Link mapping state from the response MLD (reverse) proposal. That is, after initiating the MLD and transmitting a TID-to-link mapping request frame, when the response MLD's TID-to-link mapping response frame includes a TID-to-link mapping element, the TID-Link mapping state indicated by the TID-to-link mapping element can be allowed. At this point, after initiating the MLD and receiving the TID-to-link mapping response frame from the response MLD, the transmitted TID-to-link mapping request frame does not contain a TID-to-link mapping element, or the TID-to-link mapping element does not indicate a specific TID, thus (implicitly) allowing the response MLD's (reverse) proposal for a specific TID. The response method for the initiating MLD's TID-to-link mapping request frame, as described above, is similar to the response method for the response MLD's TID-to-link mapping response frame, and therefore will not be repeated. At this point, initiating an MLD transmission TID-to-link mapping response frame (without containing TID-to-link mapping elements) instead of a TID-to-link mapping request frame can also allow a response to the TID-Link mapping status proposed by the MLD.

[0304] However, if the initiating MLD transmission does not contain a TID-to-link mapping request frame, the responding MLD can complete the TID-to-link mapping negotiation process at the beginning of the Ack frame responding to the TID-to-link mapping request frame. In other words, when a TID-to-link mapping request frame is received that does not contain a TID-to-link mapping element, the responding MLD can complete the TID-to-link mapping negotiation process by responding to the Ack frame.

[0305] Figure 18 The response method shown allows (accepts) the initiating MLD to the link mapping from the TID proposed in response to the MLD reverse proposal.

[0306] Reference Figure 18 To initiate the TID-to-link mapping negotiation process, the initiating MLD transmits a TID-to-link mapping request frame #1 to the responding MLD. The responding MLD, in response to response frame #1, can reject the link mapping for TIDs 4 to 7 and execute a (reverse) proposal. At this point, the initiating MLD can decide to allow the responding MLD to proceed with the TID-Link mapping status indicated by the TID-to-link mapping request frame #1 and request the responding MLD to complete the TID-to-link mapping.

[0307] exist Figure 18 In Example 1, after the initiating MLD receives the TID-to-link mapping request frame #1, it can transmit a TID-to-link mapping response frame #2 to complete the TID-to-link mapping process. Strictly speaking, the TID-to-link mapping response frame #2 transmitted by the initiating MLD can be an unsolicited response frame. In this case, the TID-to-link mapping response frame #2 transmitted by the initiating MLD has a configuration that does not contain TID-to-link mapping elements, and the responding MLD that receives the TID-to-link mapping response frame #2 from the initiating MLD can recognize the TID-Link mapping state that the initiating MLD wants to allow itself to (reversely) propose and complete the TID-to-link mapping process. Therefore, the responding MLD can complete the TID-to-link mapping negotiation process with the initiating MLD by responding with an Ack frame after receiving the TID-to-link mapping request frame #2.

[0308] exist Figure 18 In Example 2, after the initiating MLD receives the TID-to-link mapping request frame #1, it can transmit a TID-to-link mapping request frame #2 to complete the TID-to-link mapping process. At this time, the TID-to-link mapping request frame #2 transmitted by the initiating MLD does not contain any TID-to-link mapping elements. The responding MLD, having received the TID-to-link mapping request frame #2 from the initiating MLD, can recognize the initiating MLD's desire to allow its (reverse) proposed TID-Link mapping and complete the TID-to-link mapping process. Therefore, the responding MLD, after receiving the TID-to-link mapping response frame #2, can complete the TID-to-link mapping negotiation process with the initiating MLD by responding with an Ack frame or a TID-to-link mapping response frame that does not contain any TID-to-link mapping elements.

[0309] <Uninstructed TID to link mapping response frame usage>

[0310] Typically, the TID-to-link mapping negotiation process between MLDs begins with a TID-to-link mapping request frame that initiates the MLD transmission. This typical TID-to-link mapping negotiation is formed between the initiating MLD and the responding MLD, and the request / response frames sent and received by the two MLDs can be individually addressed frames.

[0311] However, in the case of AP MLDs, TID-to-link mapping negotiation needs to be performed with multiple non-AP MLDs in the BSS. Therefore, performing individual TID-to-link mapping negotiation with each non-AP MLD can be an expensive operation. Therefore, AP MLDs can notify non-AP MLDs of their preferred TID-Link mapping configuration by transmitting a non-individually addressed TID-to-link mapping response frame. As mentioned above, when AP MLDs notify non-AP MLDs of their preferred TID-Link mapping status, non-AP MLDs have the advantage of knowing in advance the preferred TID-Link mapping configuration of the AP MLD responding to them before initiating the TID-to-link mapping negotiation process. In other words, the non-AP MLD, as the initiating MLD, already knows the responding MLD's preference at the start of transmitting the TID-to-link mapping request frame, thus facilitating a smoother TID-to-link mapping negotiation process.

[0312] Unindicated TID-to-link mapping response frames transmitted by the AP MLD may differ from the general TID-to-link mapping request / response frames configured in the TID-to-link mapping element. More specifically, unindicated TID-to-link mapping response frames transmitted by the AP MLD may indicate the same TID once or multiple times through the TID-to-link mapping element. For example, in a special (DL / UL) TID-to-link mapping information field included in the TID-to-link mapping element, TID 0 to TID 1 may correspond to (map to) Link 1 to Link 2, while in other (DL / UL) TID-to-link mapping information fields, TID 0 to TID 4 may correspond to Link 1 to Link 3. Therefore, a non-AP MLD receiving unindicated TID-to-link mapping response frames from the AP MLD has the purpose of distinguishing between links from TID 0 to TID 1 and from TID 2 to TID 3, and can choose to set Link 1 or / to Link 2 for TID 0 to TID 1, and Link 3 for TID 3 or TID 4, etc. In other words, the AP MLD includes TID-to-link mapping elements in its transmitted beacon frames, thus helping non-AP MLDs select and configure links during the association phase. More specifically, non-AP MLDs can confirm the AP MLD's preferred TID-Link mapping status through beacon frames, and can then select and configure links according to their desired TID separation method.

[0313] Figure 19Shows an embodiment of the process of negotiating the mapping of an unsolicited TID transmitted from an AP MLD to a link mapping response frame (UnsolicitedTID-to-link mapping Response frame), as well as the TID-to-link mapping negotiation process between an AP MLD and a non-AP MLD.

[0314] Referring to Figure 19 , the AP MLD can transmit an unsolicited TID-to-link mapping response frame. In this case, the unsolicited TID-to-link mapping response frame can be transmitted as a non-individually addressed frame. That is, the unsolicited TID-to-link mapping response frame transmitted by the AP MLD can target one or more non-AP MLDS.

[0315] As Figure 19 shown, the AP MLD can map TID 0 to TID 3 to Link 1, map TID 4 to TID 5 to Link 2, and map TID 6 to TID 7 to Link 3 through the unsolicited TID-to-link mapping response frame.

[0316] As Figure 21 shown in Sequence 1 of , the non-AP MLD (initiating MLD) that receives this transmits a TID-to-link mapping request frame that does not include a TID-to-link mapping element, thereby allowing the AP MLD (responding MLD) to indicate the TID-Link mapping indicated by the unsolicited response frame, and can indicate that it wishes to execute and complete the TID-to-link mapping protocol. After receiving the TID-to-link mapping request frame that does not contain a TID-to-link mapping, the AP MLD can respond to the completion of the TID-to-link mapping protocol through a response Ack frame.

[0317] In the case of Sequence 2, the non-AP MLD (initiating MLD) can confirm that there are two link mapping options for the TID-Link mapping indicated by the AP MLD (responding MLD) through the unsolicited TID-to-link mapping response frame for TID 4 to TID 7. At this time, the non-AP MLD selects the option of mapping TID 4 to TID 7 to Link 2 to Link 3 and transmits a TID-to-link mapping request frame to the AP MLD. At this time, since the non-AP MLD does not indicate TID 0 to TID 3 in the TID-to-link mapping element of the request frame, it can be interpreted as allowing the link mapping proposal of the AP MLD for TID 0 to TID 3 (indicated by the unsolicited TID-to-link mapping response frame).

[0318] <Release of TID-to-link mapping>

[0319] The TID-to-link mapping protocol established between two MLDs can be released by one MLD transmitting a TID-to-link mapping dismantling frame and the other MLD executing an Ack response. If the TID-to-link mapping protocol established between the two MLDs is released via a TID-to-link mapping dismantling frame, then both MLDs can operate in the default TID-to-link mapping mode. That is, traffic to all TIDs of both DL and UL can be converted to the same state as when mapped to all links.

[0320] Considering the TID-to-link mapping protocol method of the present invention described above, when an MLD configuration as a TID-to-link mapping request frame is initiated, the TID-to-link mapping information field of the TID-to-link mapping element indicates all TIDs and all Links. Therefore, it can also be converted to the default TID-to-link mapping mode. More specifically, in the DL TID-to-link mapping information field contained in the TID-to-link mapping element, if the TID information subfield is indicated as 1111 1111 (8-bit embodiment) and the link information subfield is indicated as 1111 1111 (8-bit embodiment), then the TID-to-link mapping in the DL direction can be indicated by the default mode.

[0321] Alternatively, in one embodiment of the invention as described above, if the DL TID-to-link mapping information size subfield of the TID-to-link mapping element is indicated as 0, the receiving MLD can recognize that the other MLD indicates (proposes) the default TID-to-link mapping mode for the DL direction. Therefore, if the initiating MLD indicates both the DL TID-to-link mapping information size subfield and the UL TID-to-link mapping information size subfield as 0 in the TID-to-link mapping request frame, the responding MLD can recognize that the initiating MLD indicates (proposes) the default TID-to-link mapping mode. Similarly, if the responding MLD indicates both the DL / UL TID-to-link mapping information size field as 0 in the TID-to-link mapping response frame, the initiating MLD can recognize that the responding MLD indicates (reverse proposal) the default TID-to-link mapping mode.

[0322] As mentioned above, although it's possible to switch to the default TID-to-link mapping mode via a TID-to-link mapping request frame and a TID-to-link mapping response frame, the reason for needing a TID-to-link mapping dismantling frame is that the TID-to-link mapping protocol dismantling process is not formed by a protocol between the two MLDs, but rather based on the intent (will) of a specific MLD. That is, when a specific MLD needs to operate in the default TID-to-link mapping mode, the other MLD must switch to the default TID-to-link mapping mode according to the specific MLD's request. Therefore, when the specific MLD transmits a TID-to-link mapping dismantling frame, the other MLD cannot execute the reverse proposal using the TID-to-link mapping response frame and must allow the switch to the default TID-to-link mapping mode. In this case, to transmit the permission intent, the other MLD may respond with an Ack frame or a TID-to-link mapping response frame that does not include TID-to-link mapping elements.

[0323] At this point, after the special MLD and the other MLD agree to change to the default TID-to-link mapping mode, each link can be used in the default TID-to-link mapping mode for a certain period of time. That is, the two MLDs that have switched from TID-to-link mapping frame splitting to the default TID-to-link mapping mode operate (switched) to a state where they can perform transmission / reception and BA (BlockAck) responses for all TIDs on all links within a certain period of time. At this time, the certain period of time can be the time set by the EHT standard or BSS, or the time reserved between the two MLDs performing TID-to-link mapping.

[0324] For this purpose, the AP MLD can simultaneously (in one go) de-associate TID-to-link mapping modes with multiple associated non-AP MLD protocols and can switch back to the default TID-to-link mapping mode. In this case, the AP MLD can transmit non-individually addressed TID-to-link mapping disassembly frames to all associated non-AP MLDs, instead of transmitting individual TID-to-link mapping disassembly frames. At this time, after transmitting the DTIM beacon frame, the AP MLD transmits the TID-to-link mapping disassembly frame via a group-addressed frame. After receiving the DTIM beacon frame, the non-AP MLDs, during the process of receiving group-addressed frames, can identify and receive the TID-to-link mapping disassembly frame, thus switching their TID-to-link mapping mode from the AP MLD protocol to the default TID-to-link mapping mode.

[0325] At this time, a non-AP MLD that receives a TID-to-link mapping disassociation frame from a group addressing frame using a DTIM beacon frame does not perform an Ack or use a response with a TID-to-link mapping response frame and is to be converted to the default TID-to-link mapping mode. That is, a TID-to-link mapping disassociation frame transmitted by an AP MLD with multiple non-AP MLDs as objects can be directly applicable without an acknowledgment (such as Ack and TID-to-link mapping response) from a non-response MLD (non-AP MLD). This may be because a TID-to-link mapping disassociation frame transmitted after a DTIM is considered to be well received by a response MLD even without a separate response.

[0326] <Other embodiments of the TID-to-link mapping element>

[0327] Since the TID-to-link mapping element is a simple element having a function of indicating a TID-Link pair, various formats can be considered. In the above Figure 15 In one embodiment, a TID-to-link mapping element format having a structure capable of mapping one or more TID groups to one or more Link groups is considered, and other element formats having the same function can also be configured in various ways.

[0328] Figure 20 Another embodiment of the TID-to-link mapping element is shown.

[0329] Referring to Figure 20 In (a) of, the TID-to-link mapping element may include an element ID, a length (Length), an element ID extension (Extension), TID-to-link mapping control, and link mapping of TID 0 to 7 fields. The element ID, length, and element ID extension fields indicate information of the TID-to-link mapping element and information related to the element length for a response element, and have the same uses as the fields included in other elements, so detailed descriptions are omitted.

[0330] The link mappings of the TID 0 to 7 fields are each composed of 2-octet (16 bits), and each bit can correspond to a Link ID of each link. At this time, each bit of the link mapping of the TID field corresponds to a Link with a Link ID smaller by 1 than the order of the bit. More specifically, the first bit of the link mapping of the TID field corresponds to the Link with Link ID 0 (1 - 1), the second bit of the link mapping of the TID field corresponds to the Link with Link ID 1 (2 - 1), and the tenth bit of the link mapping of the TID field can correspond to the Link with Link ID 9 (10 - 1).

[0331] In other words, in the TID to link mapping element of the TID to link mapping request frame, if the link mapping of the TID'n' field is indicated as 1100 0000 0000 0000, then TID'n' can be requested to be mapped to the link corresponding to Link ID 0 to Link 1.

[0332] Reference Figure 20 (b) The TID to link mapping control field can have configurations including Direction, Default Link Mapping, and Link Mapping PresenceIndicator subfield.

[0333] The direction subfield indicates information related to the directionality of the information included in the TID-to-link mapping element. More specifically, the direction subfield indicates whether the TID-to-link mapping element is used for UL-direction TID-to-link mapping, DL-direction TID-to-link mapping, or whether it is used for UL / DL (bidirectional) direction TID-to-link mapping. For example, the direction subfield can be set to 0 / 1 / 2 respectively, thus indicating that the corresponding TID-to-link mapping element includes DL / UL / bidirectional TID-to-link mapping information respectively. In this case, the other value 3 indicated by the direction subfield (2 bits) can be reserved.

[0334] The default link mapping subfield can be a subfield indicating that the TID-to-link mapping mode proposed by the corresponding TID-to-link mapping element is the default mode (all TIDs map to all configured links). For example, a device transmitting a TID-to-link mapping element can propose (reverse proposal) the default mapping mode by setting the default link mapping subfield to 1.

[0335] That is, if the default link mapping subfield of the TID to link mapping element, which indicates DL direction information, is indicated as 1, then the TID to link mapping for the DL direction can be proposed as the default mode.

[0336] Conversely, if the default link mapping subfield of the TID to link mapping element, which indicates UL direction information, is indicated as 1, then the TID to link mapping for UL direction can be proposed as the default mode.

[0337] Alternatively, if the default link mapping subfield of the TID to link mapping element, which indicates bidirectional direction information via the direction subfield, is indicated as 1, then bidirectional (DL / UL) direction TID to link mapping can be proposed as the default mode.

[0338] As described above, a TID-to-link mapping element can include TID-to-link mapping information for UL, DL, or bidirectional directions. Therefore, a TID-to-link mapping request frame and a (indicated or unindicated) TID-to-link mapping response frame can contain one or two TID-to-link mapping elements. However, a TID-to-link mapping (request and map) frame including two TID-to-link mapping elements can have its direction subfield (TID-to-link mapping control field) set to 0 and 1 respectively. That is, it is not allowed for both TID-to-link mapping elements included in a single TID-to-link mapping frame to have their direction subfields set to 0 or 1. Furthermore, when a TID-to-link mapping frame contains a TID-to-link element with its direction subfield set to 2, no other TID-to-link elements can be included.

[0339] In this scenario, "default mode for TID-to-link mapping in the DL direction" means that for all DL directions, all TIDs are mapped to the state of the configured link. Similarly, "default mode for TID-to-link mapping in the UL direction" means that for all UL directions, all TIDs are mapped to the state of all configured links. Finally, "default mode for TID-to-link mapping in both directions" means that for both DL and UL directions, all TIDs are mapped to the state of all configured links.

[0340] As mentioned above, the default TID to link mapping mode means that for all DL and UL directions between MLDs, all TIDs are mapped to all configured links. Conversely, the default TID to link mapping state for either the DL or UL direction can be defined separately.

[0341] In addition, a default TID-to-link mapping state can be defined for each TID and Link. More specifically, the state of a specific TID mapped to all configured links can be understood as the specific TID being in the default (TID-to-link) mapping state. Similarly, the state of all TIDs mapped to specific Links can be understood as the specific Link being in the default (TID-to-link) mapping state.

[0342] For example, if a specific TID in the DL direction is in the default mapping mode (state), it means that traffic transmitted in the DL direction with that specific TID is mapped (transmittable) to the state of all configured links. As another example, if a specific link in the UL direction is in the default mapping mode (state), it means that all traffic in the UL direction is mapped to the state of that specific link.

[0343] However, the default link mapping mode in the TID to link mapping control field is not used to establish a default mapping mode for each TID and each link, but rather to establish a default mapping mode for the minimum DL or UL direction.

[0344] Alternatively, the default link mapping mode in the TID-to-link mapping control field can be used to convert the TID-to-link mapping mode between two MLDs to the default mode. That is, for both bidirectional directions to be converted to the default TID-to-link mapping mode, the default link mapping subfield is indicated as 1, so the default link mapping subfield can only be set to 1 when the direction subfield is set to 2.

[0345] The Link Map Existence Identifier subfield consists of 8 bits and indicates whether the link mapping (TID to Link Mapping Element) for each TID is included in the TID to Link Mapping Element. More specifically, if the i-th bit of the Link Map Existence Identifier subfield is indicated as 1, it means that the link mapping (i) subfield for TID i is included in the TID to Link Mapping Element. When the default link mapping subfield for the TID to Link Mapping Element is set to 1, the inclusion of the Link Map Existence Identifier subfield in the corresponding TID to Link Mapping Element can be reserved, and all bits need to be set to 0.

[0346] For example, when the identifier subfield of the link mapping is indicated as 1100 1000, the TID to link mapping element can sequentially include the link mapping subfields of TID for TID 0, TID 1, and TID 4 (i.e., the link mapping 0 subfield of TID, the link mapping 1 subfield of TID, and the link mapping 4 subfield of TID).

[0347] At this time, in TID-to-link mapping elements where the default link mapping subfield is indicated as 0, the special TID (for the TID of the direction indicated by the direction subfield) that does not include a separate TID in the link mapping subfield can be implicitly indicated by the device transmitting the TID-to-link mapping element to maintain the current link mapping state for the special TID. That is, in the above embodiment, the link mapping states for TID 2 to TID 3 and TID 5 to TID 7 can remain unchanged and maintain the previous link mapping state even if negotiated by the corresponding TID-to-link mapping elements (including the request frames of the corresponding TID-to-link mapping elements).

[0348] In other words, a TID-to-link mapping request MLD transmission does not include the TID-to-link mapping element in the link mapping subfield of the TID for a specific TID, thus allowing a request (proposal) to maintain the link mapping state already established for the specific TID. In this case, if no separate link mapping has been established for the specific TID, the specific TID can maintain its default link mapping state (mapped to all configured links). In this scenario, a TID-to-link mapping request MLD could mean transmitting a TID-to-link mapping request frame or an MLD containing a (re)association request frame with TID-to-link mapping elements.

[0349] In addition, the MLD (response MLD) that transmits an unindicated TID to link mapping response frame can indicate (reverse proposal) to the other MLD that it prefers to maintain the link mapping state that has been established for the specific TID by transmitting a TID to link mapping element that does not include the TID field for the specific TID.

[0350] Before an MLD transmits a request frame from another MLD to set up the mapping between TIDs and links, it can transmit an unindicated TID-to-link mapping response frame indicating the preferred mapping between TIDs and links. In this case, if the unindicated TID-to-link mapping response frame does not contain mapping information related to the mapping between one or more TIDs and one or more links, it can implicitly indicate the preferred mapping between one or more TIDs and one or more links.

[0351] In this case, the implicitly indicated mapping relationship can be one of the following: 1) not changing the existing mapping relationship and maintaining it effectively, 2) a mapping relationship without special preference, or 3) the default mapping relationship.

[0352] First, when an MLD implicitly prefers to maintain an existing mapping relationship without changing it by not including mapping information related to the mapping relationship in an unindicated TID to link mapping response frame, and if there is no separate link mapping established for a specific TID, it can be interpreted by the other MLD as one or more TIDs preferring a default mapping relationship (mapped on all configured links). In this case, the unindicated TID to link mapping response frame can be a (separately addressed) unindicated TID to link mapping response frame responding to the MLD's transmission of the other MLD (requesting MLD, peer MLD) to the destination device.

[0353] Second, when an MLD requests a TID-to-link mapping relationship through an unindicated TID-to-link mapping response frame that does not contain mapping information related to the mapping relationship, implicitly indicating that it has no particularly preferred mapping relationship, then the MLD does not have a particularly preferred mapping relationship. Therefore, the MLD cannot refuse the TID-to-link mapping relationship requested by the other MLD through a request frame, and must allow it. That is, since the MLD does not have a preferred TID-to-link mapping relationship, when the other MLD requests a TID-to-link mapping relationship through a request frame, the response frame must not refuse and must allow it.

[0354] Third, if the MLD implicitly prefers the default mapping relationship by not including mapping information related to the mapping relationship in the unindicated TID to link mapping response frame, then one or more TIDs are indicated as preferring the default mapping relationship in the link mapping relationship. Therefore, unlike the second case, even if the mapping relationship of the link to one or more TIDs from the other MLD is requested by the request frame, the MLD can reject the mapping relationship requested by the response frame.

[0355] However, if the other MLD requests a TID-to-link mapping in the same way as the preferred mapping indicated in the unindicated TID-to-link mapping response frame transmitted from the MLD, the MLD cannot refuse the requested mapping and must allow it. In other words, when the requesting MLD transmission from the other MLD and the responding MLD transmission from the MLD both contain the same TID-to-link mapping element in their TID-to-link mapping request frames, the responding MLD must accept the proposed (or requested) TID-to-link mapping.

[0356] The above-described method for interpreting the mapping relationship between preferred TIDs and links can be applied not only to cases where the mapping relationship between preferred TIDs and links is indicated by mapping information in response frames from unindicated TIDs to links, but also to cases where the mapping relationship between preferred TIDs and links is indicated by mapping information in response frames from (re)association response frames or TIDs to links mapping response frames.

[0357] That is, if the mapping relationship between a TID and a link requested by the request frame is not allowed, such as an association request frame or a TID to link mapping request frame, and the (re)association response frame or TID to link mapping response frame is rejected or reversed, the mapping relationship between the preferred TID and the link indicated by the (re)association response frame or TID to link mapping response frame can be interpreted by one of the three methods described above.

[0358] Specifically, as described above, the MLD requests the setting of the mapping relationship between a TID and a link from the mapping information included in the TID-to-link mapping element of the request frame (e.g., an association request frame or a TID-to-link mapping request frame). At this time, the MLD may allow or refuse the TID-to-link mapping relationship requested via the request frame. If the MLD refuses the TID-to-link mapping relationship requested via the request frame, the MLD may also refuse the mapping relationship requested via a response frame (e.g., a (re)association response frame or a TID-to-link mapping response frame).

[0359] In this scenario, the MLD rejects the mapping relationship requested via the response frame, but includes the mapping relationship between the MLD's preferred TID and the link in the mapping information of the TID-to-link mapping element, thus allowing it to be transmitted to the other MLD via the response frame. In this case, when the mapping information for the preferred mapping relationship does not include the mapping relationship between some or all TIDs and the link, the mapping relationship between the excluded TIDs and the link can be implicitly indicated as described above. The implicitly indicated mapping relationship can be one of 1) maintaining the existing mapping relationship without change, 2) having no particularly preferred mapping relationship, or 3) the default mapping relationship, and the specific interpretation method is the same as above.

[0360] After that, the other party's MLD can identify the mapping relationship preferred by the MLD through the response frame, and can retransmit the request frame to the MLD based on this.

[0361] As another embodiment of the present invention, it may explicitly include the case where the MLD rejects the requested mapping relationship between TID and link through the above-mentioned response frame, the case where the MLD includes the mapping information of the preferred TID and link mapping relationship in the TID-to-link mapping element through the response frame, and the mapping relationship between all TIDs and links. In this case, since the mapping relationship between all TIDs and links is explicitly indicated by the mapping information, the implicit interpretation method of the mapping relationship between TID and link is not applicable.

[0362] In another embodiment, the TID-to-link mapping element by default indicates a TID-to-link mapping for a specific direction (UL or DL), and may also include TID-to-link mapping proposal / indication information for other directions that are not specific directions (DL direction when the specific direction is UL, UL direction when the specific direction is DL). More specifically, when the direction subfield of the specific TID-to-link mapping element is indicated as 0 (DL direction) and the default link mapping subfield is indicated as 1, the specific TID-to-link mapping element includes the function of allowing the TID-to-link mapping request element to request the DL direction TID-to-link mapping as the default mapping. Simultaneously, the specific TID-to-link mapping element may be configured to include link mappings with one or more TID fields in the TID-to-link mapping element; in this case, to request a TID-to-link mapping to the UL direction (the opposite direction of DL indicated by the direction), a link mapping with one or more TID fields may be included.

[0363] In other words, when a TID-to-link mapping element that requests / indicates a default TID-to-link mapping for a specific direction includes a link mapping with a TID field, the link mapping with the TID field, for the direction opposite to the direction requested by the default mapping, can include information requesting the TID-to-link mapping. In this case, the link mapping existence identifier subfield of the TID-to-link mapping element can indicate which TID information is associated with the link mapping (one or more) of the TID field in the opposite direction. That is, in this situation, even if a default TID-to-link mapping for a specific direction is requested / indicated, the link mapping existence identifier subfield may not be reserved. Therefore, when the default link mapping subfield of the received TID-to-link mapping element is indicated as 1, and the corresponding link mapping existence identifier subfield of the TID-to-link mapping element is not 0, MLD can identify that a link mapping with the TID field in the opposite direction is indicated by the direction subfield.

[0364] <TID to Link Mapping Proposal Rules Considering Link Configuration>

[0365] As described above, in order to establish a TID-to-link mapping, the Requesting MLD (Initiating MLD) transmits a TID-to-link mapping request frame to the Response MLD (Response MLD). The Response MLD's response to the TID-to-link mapping response frame can allow the TID-to-link mapping proposed by the Requesting STA.

[0366] If a TID to link mapping is established / negotiated between two MLDs, then when the two MLDs transmit traffic corresponding to a specific TID, the link mapped to that specific TID will be used for transmission only.

[0367] When establishing a TID-to-link mapping between two MLDs, if a specific TID is mapped only to a link that is not yet established between the two MLDs, then that specific TID is subject to the restriction that it can only be transmitted through the unestablished link and therefore cannot be transmitted. This means that TID mappings for links that have not yet been established (associated) are invalid. Therefore, MLDs that want to establish a TID-to-link mapping negotiation may need to try mapping only the TIDs of links that are already established between them.

[0368] Therefore, an MLD that transmits a TID to a link mapping request frame to another MLD may only need to request TID mapping for links that have already been configured with that MLD. That is, it cannot request any TID mapping for links that have not yet been configured.

[0369] Therefore, when requesting an MLD to indicate which link to map to a specific TID, the bit corresponding to the ID of the link that has not been configured is always set to 0, and the TID to link mapping request can be executed.

[0370] Similarly, the MLD (response MLD) that suggests a TID-to-link mapping to the requesting MLD will always set the bit corresponding to the link that has not been configured to 0, thus enabling the TID-to-link mapping response. That is, no TID mapping can be suggested for a link that has not been configured.

[0371] Therefore, when responding to an MLD's proposal to map a link to a specific TID, the bit corresponding to the ID of the link for which the setting has not yet been performed is always set to 0 (either indicated or unindicated) to execute the TID-to-link mapping response. In this case, an unindicated TID-to-link mapping response may mean that the specific MLD is proposing its preferred TID-to-link mapping suggestion to the other MLD, transmitting a TID-to-link mapping response frame.

[0372] In summary, the MLD transmitting the TID to the link mapping element will always set the Link ID bit (TID to link mapping element) of the link corresponding to the link between the other MLD that has not been configured. In other words, the TID to link mapping element transmitted / received between two MLDs will always set the Link ID of the link between the two MLDs that has not been configured.

[0373] However, including the TID-to-link mapping element in the MLD transmitted in the (re)association request frame only requests the TID mapping for links that have been requested to be set by the other MLD. That is, in the MLD transmitted in the (re)association request frame, the bit of the Link ID corresponding to the link that has not been requested to be set by the other MLD (TID-to-link mapping element) is always set to 0.

[0374] Similarly, MLDs that include TID-to-link mapping elements in the (re)association response frame transmission only favor TID mappings for link suggestions that accept the configuration. That is, MLDs that include TID-to-link mapping elements in the (re)association response frame transmission will always set the bit of the Link ID (TID-to-link mapping element) corresponding to the link that the other MLD has not accepted the configuration to 0.

[0375] At this point, since the maximum number of Link IDs that can be set between MLDs is limited to a maximum of 14 (Link IDs use 0 to Link ID 14 to distinguish a maximum of 15 Links), the 16th bit of the link mapping in the TID field (i.e., the bit corresponding to Link ID 15) is always set to 0.

[0376] <Methods for configuring link mapping for valid TID fields>

[0377] Referring to the above embodiments of the present invention, the TID-to-link mapping element transmitted / received between MLDs can be configured such that a portion of the bits in the link mapping of the TID field is always indicated as 0.

[0378] If the number of links between the two MLDs performing TID-to-link mapping negotiation is only two, then 14 bits of the 16 bits in the link mapping of the TID field (the 13 bits corresponding to the Link ID of the unconfigured link + the 16th bit) may always be indicated as 0. This repeated indication of 0 bits in the TID-to-link mapping element can cause overhead issues, so a more efficient TID field link mapping configuration should be considered.

[0379] According to one embodiment of the present invention, the size of the link mapping included in each TID field of the TID-to-link mapping element can be determined based on the number of Links set between the MLDs of the transmission / reception TID-to-link mapping elements.

[0380] For example, if the request MLD and response MLD are set up through three links, the TID to link mapping element for the request MLD and response MLD transmission / reception can include a 3-bit TID field for the link mapping.

[0381] According to one embodiment of the present invention, the link ID corresponding to each bit of the link mapping included in the TID field of the TID-to-link mapping element can be determined based on the Link ID set between the transmission / reception TID and the MLD of the link mapping element. In this case, the Link corresponding to the link mapping in the TID field can correspond to each bit in descending order of Link ID.

[0382] For example, if the request MLD and response MLD are set through three links (Link ID 0, Link ID 3, Link ID 10), then the 3 bits of the link mapping in the TID field of the link mapping element transmitted / received by the request MLD and response MLD can correspond to Link ID 0, Link ID 3, and Link ID 10, respectively. That is, when the 3 bits of the link mapping in the TID field of a specific TID are indicated as 010, the specific TID can be interpreted as a request / indication mapping to the link corresponding to Link ID 3.

[0383] In other words, after performing multi-link (re)configuration, the MLD of the transmit / receive TID to link mapping element determines (selects and identifies) the link mapping of the TID field based on the number of links configured with the peer MLD.

[0384] In other words, after performing multi-link (re)configuration, the MLD of the transmit / receive TID to link mapping element considers the Link ID set with the peer MLD to determine the Link corresponding to each bit of the link mapping in the TID field.

[0385] Furthermore, when using a link mapping with a variable-length TID field according to an embodiment of the present invention, a padding field for maintaining the length of the TID-to-link mapping element to multiple octets may be included in the TID-to-link mapping element. In this case, the padding field may be included after the link mapping of the TID field and may have a size of less than 1 octet.

[0386] Figure 21 An example of a TID-to-link mapping element is shown, which includes a variable-length TID field.

[0387] Reference Figure 21 The TID to link mapping element can have a configuration that includes a link mapping with a variable-length TID field and a padding field.

[0388] The link mapping of the TID field is a field whose size is determined by the number of links set between the transmit / receive TID and the MLD of the link mapping element (including frames). That is, if 3 links are set between the transmit / receive TID and the MLD of the link mapping element, the link mapping of the TID field has a size of 3 bits, and if 5 links are set, the link mapping of the TID field can have a size of 5 bits.

[0389] If the link mapping of the TID field has a size of 3 bits, and the link mapping of the TID field for 3 TIDs is included in the TID-to-link mapping element, then the size of the link mapping of the TID field can be a total of 9 bits. In this case, a 7-bit padding field is included in the TID-to-link mapping element, so the size of the link mapping of the TID field plus the size of the padding field can be configured as 2-octets.

[0390] Furthermore, each bit of the link mapping in the TID field corresponds to the link for which the setting was performed. For example, in the TID-to-link mapping element transmitted and received between two MLDs performing ML settings via LinkID 0, Link ID 3, and Link ID 7, the link mapping in the TID field is 3 bits in size. The first bit of each TID field's link mapping can correspond to Link ID 0, the second bit to Link ID 3, and the third bit to Link ID 7. That is, if the bit of Link ID 3 in the link mapping of the TID field corresponding to a special TID (the 'Special TID' field of the TID's link mapping) is indicated as 1, then the special TID will be requested (proposed) to be mapped to the link with Link ID 3.

[0391] <(Re-configured) TID to Link Mapping Management>

[0392] AP MLDs and non-AP MLDs can perform (re)setting changes to the configuration of links. That is, AP MLDs and non-AP MLDs can add or remove configured links by resetting. In this case, the reset between AP MLDs and non-AP MLDs can be performed through (re)association request / response frame exchanges. When a reset is performed between two MLDs, it must be accompanied by the management of TID mappings associated with the configured links added or deleted through the reset. For ease of description, the following embodiments of the invention do not mention the directionality (UL or DL) of TID-to-link mappings. However, since all TID-to-link mappings are directional, even without a separate mention of the TID-to-link mapping direction, it can be understood that a description of a specific direction or bidirectional (two-way) mapping is provided.

[0393] First, when adding a configuration link by resetting, the added configuration link can be set to the state of all TID mappings (the default TID mapping state of the link).

[0394] This can be an additional setting applied to the link's TID mapping state when the (re)association request frame for resetting the exchange does not include a TID-to-link mapping element.

[0395] However, when a setup link is added via a (re)association request frame containing a TID-to-link mapping element, the added setup link can map TIDs based on the information indicated in the TID-to-link mapping element. In this case, since the method for determining the link mapped to the added setup link is no different from the aforementioned TID-to-link mapping negotiation process, a detailed description will be omitted.

[0396] Next, when a configured link is removed (deconfigured) by resetting, the TID mapped to the removed link can be changed to the default mapping state. More specifically, by resetting the TID mapped to the deconfigured link, it can be changed to a state mapped to all configured links (excluding the deconfigured link) after the reset (i.e., the default link mapping state of the TID). This can be a TID-to-link mapping management method considered when a special TID is only mapped to a special link, and the special link is deconfigured by resetting, thus preventing the special TID from changing to a state not mapped to any configured link.

[0397] However, if the TID mapped to the special link whose setting has been removed is also mapped to the state of other setting links (which remain in the setting state after the reset), then even if the setting of the special link is removed, the special TID will not be converted to the state mapped to all setting links.

[0398] Furthermore, when a (re)association request frame for resetting the exchange includes a TID-to-link mapping element, the TID mapped to the link whose setting has been removed can be mapped to other set links based on the information indicated by the TID-to-link mapping element.

[0399] That is, after MLD is reset, if a special TID becomes unmapped on any set link, the special TID can be changed (set) to be mapped to all set links (the default link mapping state of the TID).

[0400] Alternatively, MLD can change (set) a special TID (which is a TID that is not mapped to any set link) to a state mapped to a special set link in a pre-reserved manner. In this case, the pre-reserved manner can have several methods, such as changing it to be mapped to the set link with the smallest Link ID index, or changing it to be mapped to the most recently set link (excluding deactivated links).

[0401] In special cases, if a special link is reset while other links are deconfigured (i.e., the number of configured links remains unchanged, only the Link ID of the configured link changes), the TID mapped to the deconfigured link can be automatically mapped to the added configured link. This can be understood as a limited application of TID-to-link mapping conversion when the (re)association request frame exchanged during the reset does not include TID-to-link mapping elements. A similar TID-to-link mapping conversion can also be applied when the number of links added during the reset is one or more, and the number of deconfigured links is one or more. For example, if two configured links are deconfigured and one link is added (configured) during the reset, the TID mapped to the two deconfigured links can be automatically mapped to the one added link. As another example, if one configured link is deconfigured and two links are added (configured) during the reset, the TID mapped to the one deconfigured link can be automatically mapped to the two added links. As another example, if two setup links are reset and two links are attached (set), the TIDs mapped to the two reset links (the sum of the TIDs mapped to the two links) can be automatically mapped to the two attached links respectively.

[0402] Alternatively, to simplify TID-to-link mapping management, removing an MLD that sets up a link via Resetup might require a conversion of all TIDs to the default TID-to-link mapping mode (all TIDs to all set links). In this case, the condition for converting an MLD that removes a link via Reset to the default TID-to-link mapping mode can be limited to a request frame that does not contain a TID-to-link mapping element in the (re)association request frame exchanged to perform the reset. That is, if a new TID-to-link mapping negotiation is not performed (completed) along with the reset, the MLD whose set link is removed via Reset might need to be converted to the default TID-to-link mapping mode. In this case, converting an MLD to the default TID-to-link mapping mode might mean that the TID-to-link mappings established between MLDs are released (the negotiated TID-to-link mappings are torn down). Alternatively, converting an MLD to the default TID-to-link mapping mode might consider TID-to-link mappings that were not negotiated by the MLD.

[0403] Therefore, in order to remove the TID-to-link mapping element from the (re)association request frame that has been set up for transmission by resetting, a function similar to / the same as the (re)association request frame containing the disassembly element can be performed.

[0404] Alternatively, when two MLDs with negotiated TID-to-link mappings (excluding the default mode) de-link by resetting, a new TID-to-link mapping negotiation may be forced to be performed via a (re)association request / response frame. That is, the MLD with negotiated TID-to-link mappings and the requesting MLD to de-link by resetting may require the (re)association request frame to include a TID-to-link mapping element.

[0405] Furthermore, when an MLD with negotiated TID-to-link mapping and an AP MLD that performs a reset receive a link reset, it can respond to a (re)association response frame that does not include a TID-to-link mapping element. That is, when an AP MLD receives a link reset, it may be required to accept a TID-to-link mapping request along with the TID-to-link mapping.

[0406] Figure 22 An embodiment of a method for managing the TID-to-link mapping of two MLDs by adding a setup link through a reset is shown.

[0407] Reference Figure 22 AP MLD and non-AP MLD can perform ML settings through Link 1 and Link 2. In addition, AP MLD and non-AP MLD can be in a state of performing TID to link mapping negotiation, mapping TID 0 to TID 3 to Link 1 and mapping TID 4 to TID 7 to Link 2.

[0408] The AP MLD and non-AP MLD can additionally configure Link 3 to perform ML settings through all three links. For this purpose, the non-AP MLD can perform a reset via a (re)association request frame. When the AP MLD allows (accepts) additional settings for Link 3, the AP MLD and non-AP MLD change to the ML setting state through Link 1 to Link 3.

[0409] Since Link 3 was not configured when AP MLD and non-AP MLD performed TID-to-link mapping negotiation on Link 1 and Link 2, there was no established negotiated TID mapping state. Therefore, by resetting the newly configured Link 3, the default TID mapping state (the state where all TIDs are mapped) is set to be completed for both bidirectional (UL and DL, bidirectional).

[0410] If a non-AP MLD contains a TID-to-link mapping element in a (re)association request frame used for reset, and the contained TID-to-link mapping element requests a separate TID-to-link mapping for Link 3, then Link 3 can be set to a non-default TID mapping state.

[0411] Figure 23 An embodiment of a management method is shown that involves resetting the TID-to-link mapping of two MLDs for a link whose settings have been removed.

[0412] Reference Figure 23 The AP MLD and non-AP MLD perform ML settings through the initial three links. Furthermore, the AP MLD and non-AP MLD perform TID-to-link mapping negotiation for Links 1 to 3, such that for bidirectional (bidirectional) Link 1 is mapped to TID 0 to TID 2, Link 2 is mapped to TID 3 to TID 4, and Link 3 is mapped to TID 5 to TID 7. The non-AP MLD can transmit a (re)association request frame to the AP MLD to change the ML settings, maintaining only the links for Links 1 and 2 and removing the setting for Link 3. Upon receiving the (re)association request frame, the AP MLD recognizes that the requested association for Link 1 is only Links 1 and 2, and responds to the (re)association request frame, maintaining the settings for Links 1 and 2 and allowing the removal of the setting for Link 3. In this case, the reset process of both the AP MLD and non-AP MLD is successfully completed, thereby removing the setting of Link 3 that was already configured between the AP MLD and non-AP MLD.

[0413] As mentioned above, if the connection between the AP MLD and non-AP MLD is removed, the mapping will be to the connection where the connection was removed. Figure 23 The TID of Link 3) has space to change to a state where it is not mapped to any set link.

[0414] Therefore, as Figure 23 As shown in Case 1 of (a), both AP MLD and non-AP MLD can automatically map TID 5 to TID 7, which are mapped to Link 3, to Links that remain set. In Case 1 of (a), even if Link 3 is deactivated (reset complete), since Link 1 and Link 2 remain set links, TID 5 to TID 7, which are mapped to Link 3, are automatically mapped to Link 1 and Link 2.

[0415] Or, such as Figure 23As shown in case (b) 2, during the reset process of Link 3 being deactivated, both AP MLD and non-AP MLD can be converted to the default TID-to-link mapping mode, such as deactivating the negotiated TID-to-link mapping. In other words, after the two MLDs are reset, they can perform TID-to-link mapping management similar to the TID-to-link mapping deactivation process.

[0416] Figure 24 A flowchart illustrating an example of a method for mapping TIDs and links according to the present invention is shown.

[0417] Reference Figure 24 As a logical entity, a STA (Standard Operating System) can be affiliated with one or more devices' MLDs, which can map one or more TIDs and one or more links to each other's MLDs. In the following text, an MLD can be an AP MLD or a non-AP MLD.

[0418] Specifically, an MLD can transmit a request frame (S24010) to another MLD for mapping between traffic identifiers (TIDs) and links. At this time, the request frame may include first mapping information for setting the mapping relationship between at least one TID and at least one link among a plurality of TIDs, as well as information related to the number of at least one TID that needs to be mapped.

[0419] Before transmitting the request frame, the MLD can receive a frame containing second mapping information from the other MLD. This second mapping information is used to set the mapping relationship between one or more TIDs and one or more links. That is, the MLD can receive an unindicated TID-to-link mapping response frame from the other MLD, which contains the second mapping information, representing a preferred mapping relationship between one or more TIDs and one or more links.

[0420] In this case, as described above, it can be implicitly indicated that the second remaining TID among multiple TIDs, other than one or more TIDs, does not have a preferred special mapping relationship or a preferred mapping relationship.

[0421] If the preferred special mapping is a previously set mapping or a default mapping, and there is no default mapping or preferred mapping for the special mapping, the mapping for at least one TID that overlaps with the second remaining TID may not be indicated by the response frame.

[0422] After this, the MLD can receive a response frame from the other MLD as a response to the request frame (S24020).

[0423] At this point, the first remaining TID among the multiple TIDs, excluding at least one TID, effectively maintains the mapping relationship previously set with the link, or applies the default mapping relationship. The first remaining TID is not indicated by the first mapping information to have a mapping relationship with a specific link.

[0424] One of the links in at least one link can be mapped to one or more TIDs in at least one TID. The default mapping relationship can refer to the state of mapping TIDs and all links.

[0425] In addition, the default mapping can be applied when the first remaining TID is set to the default mapping before the transmission of the request frame.

[0426] The request frame may also include transmission direction information showing the transmission direction for at least one TID, and multiple TIDs may be mapped only between the MLD and the peer MLD that transmits the request frame on the established link.

[0427] In addition, the response frame can indicate whether a mapping relationship between at least one of a plurality of TIDs and at least one link is allowed.

[0428] Furthermore, when a mapping relationship between at least one of the multiple TIDs and at least one link is allowed, the response frame may not include second mapping information for other mapping relationships between at least one of the multiple TIDs and at least one link. And when a mapping relationship between at least one of the multiple TIDs and at least one link is not allowed, the response frame may also include second mapping information indicating a mapping relationship different from the first mapping relationship for at least one of the multiple TIDs.

[0429] At this time, as Figures 10 to 16 The MLD can receive management frames from the other MLD, and the management frames can be transmitted only on at least one link that is mapped to at least one TID. Furthermore, the management frames are transmitted based on the assigned Access Category (AC), and can be transmitted on at least one link regardless of the Access Category set on the at least one link.

[0430] In the case of management frames, no special TID is assigned and there is no TID allocation, so the mapping between TIDs and links may not be applied. Therefore, regardless of the mapping between TIDs and links, management frames can be transmitted to all links. In this case, the link to which the management frame is transmitted may be an enabled link where the mapping between TIDs and links is set.

[0431] In this scenario, when management frames are transmitted solely by enabling the link, situations may arise where management frames cannot be transmitted when the link is not enabled, except for broadcast management frames transmitted independently of the link. Therefore, in the case of special management frames, transmission is possible even without enabling the link.

[0432] The description of this invention is for illustrative purposes, and those skilled in the art will understand that the invention can be readily modified into other specific forms without changing the technical concept or essential features. Therefore, it should be understood that the embodiments described above are intended to be illustrative in various senses and not restrictive. For example, each component described as a single type can be implemented in a distributed manner, and similarly, components described as distributed can also be implemented in a combined manner.

[0433] The scope of this invention is indicated by the claims to be set forth below, rather than by a detailed description, and the meaning and scope of the claims and all variations or modifications derived therefrom shall be construed as being covered within the scope of this invention.

Claims

1. A non-access point multilink device (NMPMLD) configured to operate in a wireless communication system, the NMPMLD comprising: Communication module; as well as A processor configured to control the communication module. The processor is configured as follows: A request frame is transmitted to the AP MLD, the request frame including a TID-to-link mapping element associated with the link mapped to each of one or more Traffic Identifiers (TIDs), and Receive a response frame as a response to the request frame. Specifically, when all of the first links of a first TID mapped to one or more TIDs are removed based on a multi-link reconfiguration process related to the removal or addition of links, the first TID is mapped to all remaining enabled links.

2. The non-AP MLD according to claim 1, wherein The response frame indicates whether the mapping indicated by the TID to the link mapping element is accepted.

3. The non-AP MLD according to claim 1, in, When the first TID is mapped to any remaining setup link due to the removal of some of the setup links mapped to the first TID, the state of the first TID mapped to all remaining enabled links is not changed.

4. The non-AP MLD according to claim 1, in, The TID-to-link mapping element includes: i) a link mapping field for one or more TIDs, and ii) a link mapping presence subfield indicating the presence or absence of each of the link mapping fields for the one or more TIDs.

5. The non-AP MLD according to claim 4, in, Each indication in the link mapping field of the one or more TIDs is mapped to the link of the corresponding TID in the one or more TIDs.

6. The non-AP MLD according to claim 4, in, When the link mapping field of the TID used for the first TID does not exist, the most recent TID to link mapping of the first TID remains unchanged and is valid.

7. The non-AP MLD according to claim 1, in, When no TID-to-link mapping is performed for any of the one or more TIDs, the TID is mapped to all the remaining enabled links.

8. The non-AP MLD according to claim 1, in, The request frame further includes transmission direction information indicating the transmission direction of the one or more TIDs.

9. The non-AP MLD according to claim 1, wherein, The processor is configured as follows: Receive management frames, The management frame is transmitted only on the link mapped to the one or more TIDs.

10. The non-AP MLD according to claim 9, in, The management frame is transmitted based on the assigned Access Class (AC).

11. A method for transmitting frames in a wireless communication system by a non-access point multilink device (Non-AP MLD), the method comprising: Transmit a request frame to the AP MLD, the request frame including a TID-to-link mapping element associated with the link mapped to each of the one or more traffic identifiers (TIDs); as well as Receive a response frame as a response to the request frame. Specifically, when all of the first links of a first TID mapped to one or more TIDs are removed based on a multi-link reconfiguration process related to the removal or addition of links, the first TID is mapped to all remaining enabled links.

12. The method according to claim 11, in, The response frame indicates whether the mapping indicated by the TID to the link mapping element is accepted.

13. The method according to claim 11, in, When the first TID is mapped to any remaining setup link due to the removal of some of the setup links mapped to the first TID, the state of the first TID mapped to all remaining enabled links is not changed.

14. The method according to claim 11, in, The TID-to-link mapping element includes: i) a link mapping field for one or more TIDs, and ii) a link mapping presence subfield indicating the presence or absence of each of the link mapping fields for the one or more TIDs.

15. The method according to claim 14, in, Each indication in the link mapping field of the one or more TIDs is mapped to the link of the corresponding TID in the one or more TIDs.

16. The method according to claim 14, in, When the link mapping field of the TID used for the first TID does not exist, the most recent TID to link mapping of the first TID remains unchanged and is valid.

17. The method according to claim 11, in, When no TID-to-link mapping is performed for any of the one or more TIDs, the TID is mapped to all the remaining enabled links.

18. The method according to claim 11, in, The request frame further includes transmission direction information indicating the transmission direction of the one or more TIDs.

19. The method of claim 11, further comprising: Receive management frames, The management frame is transmitted only on the link mapped to the one or more TIDs.

20. The method according to claim 19, in, The management frame is transmitted based on the assigned Access Class (AC).

21. An access point multilink device (AP MLD) for a wireless communication system, the AP MLD comprising: Communication module; as well as A processor configured to control the communication module. The processor is configured as follows: Receive a request frame from a non-AP MLD, the request frame including a TID-to-link mapping element associated with the link mapped to each of one or more Traffic Identifiers (TIDs), and Transmit a response frame as a response to the request frame. Specifically, when all of the first links of a first TID mapped to one or more TIDs are removed based on a multi-link reconfiguration process related to the removal or addition of links, the first TID is mapped to all remaining enabled links.

Images