Multi-link wireless communication method and wireless communication terminal using the method

Abstract

A non-access point (non-AP) multilink device is disclosed, comprising multiple stations operating on multiple links respectively. The multilink device includes a transceiver and a processor. The processor receives beacon frames including TIM elements and multilink service elements from the AP multilink device, and determines whether services intended for the non-AP multilink device are cached on the AP multilink device based on a partial virtual bitmap subfield of the TIM element.

Description

Technical Field

[0001] This invention relates to a wireless communication method using multiple links and a wireless communication terminal using the method. Background Technology

[0002] In recent years, with the expansion of mobile device supply, Wireless LAN (WLAN) technology, which can provide fast wireless internet services to mobile devices, has gained attention. WLAN 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.

[0003] 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 a maximum communication speed of 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 the communication speed 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 a maximum communication speed of 54 Mbps and meets backward compatibility, which is of significant interest. Moreover, it is superior to IEEE 802.11a in terms of communication range.

[0004] 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.

[0005] As the supply of wireless LANs becomes more active, and further, as applications using wireless LANs diversify, 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 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 at least 1 Gbps can be enabled across multiple stations, and maximum single-link speeds can reach at least 500 Mbps. This is achieved through concepts that extend the wireless interface received by 802.11n, such as wider wireless frequency bandwidth (maximum 160 MHz), more MIMO spatial streams (maximum 8), multi-user MIMO, and high-density modulation (maximum 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 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.

[0006] 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.

[0007] To support new multimedia applications, such as high-definition video and real-time gaming, new wireless LAN standards are being developed to increase maximum 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 / 6GHz band through increased bandwidth, increased spatial streaming, and multi-AP collaboration. Summary of the Invention

[0008] Technical issues

[0009] The embodiments of the present invention aim to provide a wireless communication method using multiple links and a wireless communication terminal using the method.

[0010] Solution

[0011] According to an embodiment of the present invention, a non-AP multi-link device comprising multiple stations operating on multiple links includes a transceiver and a processor. The processor: receives a beacon frame including a TIM element and a multi-link service element from an AP multi-link device; and determines, based on a partial virtual bitmap subfield of the TIM element, whether the service for the non-AP multi-link device is cached on the AP multi-link device. In this case, the partial virtual bitmap subfield includes one or more first bits and one or more second bits, wherein a bit set to 1 among the one or more first bits indicates that the service for the non-AP multi-link device corresponding to the bit is cached on the AP multi-link device, and a bit set to 1 among the one or more second bits indicates whether the service for the non-AP station corresponding to the bit is cached on the AP multi-link device. When a service for a non-AP multi-link device is cached on an AP multi-link device, the processor determines, based on the link service indication list subfields of the multi-link service element, which link among the multiple links the service for the non-AP multi-link device is cached on, or which link among the multiple links the AP multi-link device recommends the non-AP multi-link device to retrieve the service transmission. At this time, each link service indication list subfield includes n link service indication bitmap subfields, where n is the sum of the number of bits set to 1 in the one or more first bits and the number of bits set to 1 in the one or more second bits. Each of the n link service indication bitmap subfields is mapped to the non-AP multi-link device corresponding to the bit set to 1 in the one or more first bits and the non-AP station corresponding to the bit set to 1 in the one or more second bits.

[0012] Each link service indication bitmap subfield of a non-AP station mapped to a bit set to 1 in one or more of the second bits can be set to a reserved bit.

[0013] The value of the reserved bit can be 0.

[0014] When the non-AP multi-link device and the AP multi-link device successfully perform TID-to-link mapping, and all TIDs are not mapped to all links, the service indication bitmap subfield of each link mapped to the non-AP multi-link device can indicate whether there is a service cached for the non-AP multi-link device on each of the multiple links.

[0015] When the default mapping is applied to the link between the non-AP multi-link device and the AP multi-link device, the link service indication bitmap subfield mapped to the non-AP multi-link device can indicate which of the multiple links the non-AP multi-link device is recommended to guide service transmission on. In this case, the default mapping is a mapping where all TIDs are mapped to all links.

[0016] In the bits of each link service indication bitmap subfield mapped to the non-AP multi-link device, the bits corresponding to links not set by the AP multi-link device or the non-AP multi-link device can be set as reserved bits.

[0017] In the bit fields of each link service indication bitmap subfield mapped to the non-AP multi-link device, the bit corresponding to the disabled link of the non-AP multi-link device can be set to a reserved bit. The disabled link can be a link in which uplink and downlink transmissions are suspended.

[0018] The IDs of the multiple links can be mapped in ascending order to the bits of the service indication bitmap subfield of each link mapped to the non-AP multi-link device.

[0019] When the AP transmitting the beacon frame in the AP multilink device does not belong to a multiple BSSID set, the range of values ​​that the AP multilink device can allocate as Association IDs (AIDs) can be determined based on the value of the Group Addressing BU Indicator Index subfield. The value of the Group Addressing BU Indicator Index subfield can indicate the number of bits used to indicate a cached group addressing frame that corresponds to an AP in the AP multilink device that is different from the AP transmitting the beacon frame.

[0020] When the AP transmitting the beacon frame in the AP multi-link device belongs to a multiple BSSID set, the range of values ​​that the AP multi-link device can allocate as AIDs can be determined based on the value of the Group Addressing BU Indicator Index subfield and the bitmap limit. The bitmap limit can be 48 bits.

[0021] According to an embodiment of the present invention, an access point (AP) multilink device comprising multiple stations operating on multiple links includes a transceiver and a processor. The processor sets a TIM element and a multilink service element included in a beacon frame to be sent to a non-AP multilink device. In this case, the TIM element includes a partial virtual bitmap subfield. The partial virtual bitmap subfield includes one or more first bits and one or more second bits, wherein a bit set to 1 among the one or more first bits indicates that the service for the non-AP multilink device corresponding to the bit is cached on the AP multilink device, and a bit set to 1 among the one or more second bits indicates whether the service for the non-AP station corresponding to the bit is cached on the AP multilink device. When the service for the non-AP multilink device is cached on the AP multilink device, the processor sets the link service indication list subfield of the multilink service element based on which link among the multiple links the service for the non-AP multilink device is cached on or which link among the multiple links the AP multilink device recommends the non-AP multilink device to guide (acquire) service transmission.

[0022] The processor uses the transceiver described above to send the beacon frame.

[0023] The link service indication list subfield includes n link service indication bitmap subfields. n is the sum of the number of bits set to 1 in the one or more first bits and the number of bits set to 1 in the one or more second bits. Furthermore, each of the n link service indication bitmap subfields is mapped to a non-AP multi-link device corresponding to the bits set to 1 in the one or more first bits and a non-AP station corresponding to the bits set to 1 in the one or more second bits.

[0024] The processor can set the link service indication bitmap subfields of non-AP stations that are mapped to the bits that are set to 1 in the one or more second bits to reserved bits.

[0025] The value of the reserved bit can be 0.

[0026] When the non-AP multi-link device and the AP multi-link device successfully perform TID to link mapping, and all TIDs are not mapped to all links, the service indication bitmap subfield of each link mapped to the non-AP multi-link device can indicate whether there is a service for the non-AP multi-link device cached on each of the multiple links.

[0027] When the default mapping is applied to a link between the non-AP multi-link device and the AP multi-link device, the link service indication bitmap subfield mapped to the non-AP multi-link device indicates which of the multiple links the non-AP multi-link device is recommended to guide service transmission on. In this case, the default mapping can be a mapping where all TIDs are mapped to all links.

[0028] The processor can set the bits corresponding to the links not set in the AP multi-link device or the non-AP multi-link device in the bit map subfield of each link service indication bitmap mapped to the non-AP multi-link device as reserved bits.

[0029] The processor can reserve the bits corresponding to the disabled links of the non-AP multi-link device in the bitmap subfields of each link service indication bitmap mapped to the non-AP multi-link device. The disabled link can be a link in which uplink and downlink transmissions are suspended.

[0030] The IDs of the multiple links can be mapped in ascending order to the bits of the service indication bitmap subfield of each link mapped to the non-AP multi-link device.

[0031] When the AP transmitting the beacon frame in the AP multilink device does not belong to a multiple BSSID set, the range of values ​​that the AP multilink device can allocate as Association IDs (AIDs) can be determined based on the value of the Group Addressing BU Indicator Index subfield. The value of the Group Addressing BU Indicator Index subfield can indicate the number of bits used to indicate a cached group addressing frame that corresponds to an AP in the AP multilink device that is different from the AP transmitting the beacon frame.

[0032] When the AP transmitting the beacon frame in the AP multi-link device belongs to a multiple BSSID set, the range of values ​​that the AP multi-link device can allocate as AIDs can be determined based on the value of the Group Addressing BU Indicator Index subfield and the bitmap limit. In this case, the bitmap limit can be 48 bits.

[0033] An operation method for a non-access point (non-AP) multi-link device, the non-AP multi-link device comprising multiple stations operating on multiple links respectively, the operation method comprising the following steps: receiving a beacon frame including a TIM element and a multi-link service element from an AP multi-link device; determining, based on a partial virtual bitmap subfield of the TIM element, whether the service for the non-AP multi-link device is cached on the AP multi-link device, wherein the partial virtual bitmap subfield includes one or more first bits and one or more second bits, and a bit set to 1 among the one or more first bits indicates the service for the non-AP multi-link device corresponding to the bit. The services of the link device are cached on the AP multi-link device, and the bits set to 1 in one or more second bits indicate whether the services for the non-AP station corresponding to the bit are cached on the AP multi-link device; and when the services for the non-AP multi-link device are cached on the AP multi-link device, based on the link service indication list subfields of the multi-link service element, it is determined which link among the multiple links the services for the non-AP multi-link device are cached on, or which link among the multiple links the AP multi-link device recommends the non-AP multi-link device to guide (acquire) service transmission. The link service indication list subfields include n link service indication bitmap subfields, where n is the value of adding the number of bits set to 1 in one or more first bits to the number of bits set to 1 in one or more second bits, and each of the n link service indication bitmap subfields is mapped to the non-AP multi-link device corresponding to the bit set to 1 in one or more first bits and the non-AP station corresponding to the bit set to 1 in one or more second bits.

[0034] Each link service indication bitmap subfield of a non-AP station mapped to a bit set to 1 in one or more of the second bits can be set to a reserved bit.

[0035] Beneficial effects

[0036] Embodiments of the present invention provide an effective wireless communication method using multiple links and a wireless communication terminal using the method. Attached Figure Description

[0037] Figure 1 The figure illustrates a wireless LAN system according to an embodiment of the present invention.

[0038] Figure 2 The figure illustrates a wireless LAN system according to another embodiment of the present invention.

[0039] Figure 3The illustration shows the configuration of a station according to an embodiment of the present invention.

[0040] Figure 4 The diagram illustrates the configuration of an access point according to an embodiment of the present invention.

[0041] Figure 5 This diagram illustrates the process of setting up a link between a station and an access point.

[0042] Figure 6 The diagram illustrates the Carrier Sense Multiple Access (CSMA) / Collision Avoidance (CA) method used in wireless LAN communication.

[0043] 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.

[0044] Figure 8 The illustrations depict various Extremely High Throughput (EHT) Physical Protocol Data Unit (PPDU) formats according to embodiments of the present invention, as well as examples of methods for indicating such formats.

[0045] Figure 9 The illustration shows a multi-link device according to an embodiment of the present invention.

[0046] Figure 10 The illustration shows a multi-link mapping method based on a TID-to-link mapping method according to an embodiment of the present invention.

[0047] Figure 11 The illustration shows a power management operation performed by a station according to an embodiment of the present invention.

[0048] Figure 12 The illustration shows the format of a TIM element according to an embodiment of the present invention.

[0049] Figure 13 The illustration shows the format of a multi-link traffic element according to an embodiment of the present invention.

[0050] Figure 14 The illustration shows a method according to an embodiment of the present invention for signaling services cached on an AP multilink device through partial virtual bitmap subfields of multilink service elements and TIM elements.

[0051] Figure 15 The figure illustrates a method for setting up multi-link service elements according to an embodiment of the present invention.

[0052] Figure 16 The illustration illustrates a method for setting the per-link traffic bitmap subfields of a multi-link service element when the link set operated by the AP multi-link device is different from the link set operated by the non-AP multi-link device communicating with the AP multi-link device.

[0053] Figure 17 The illustration shows a method for determining the links indicated by the service bitmap subfields of each link based on the TID-to-link mapping according to an embodiment of the present invention.

[0054] Figure 18 The illustration shows a method for setting the link service indication bitmap subfields of a multi-link service element by an AP multi-link device according to another embodiment of the present invention.

[0055] Figure 19 The figure illustrates an EHT operation element according to an embodiment of the present invention.

[0056] Figure 20 The illustration shows a virtual bitmap of service instructions according to an embodiment of the present invention.

[0057] Figure 21 The illustration shows a virtual bitmap of service instructions according to an embodiment of the present invention.

[0058] Figure 22 The diagram illustrates the signaling associated with multi-link elements and MediumSyncDelay according to an embodiment of the present invention.

[0059] Figure 23 The diagram illustrates a multi-link setup process according to an embodiment of the present invention.

[0060] Figure 24 The illustration shows the format of a Reduced Neighbor Report element according to an embodiment of the present invention.

[0061] Figure 25 The figure illustrates a method for setting the ID of a multi-link device according to an embodiment of the present invention.

[0062] Figure 26 The illustration shows a method for assigning AIDs to non-AP stations attached to a multi-link device according to an embodiment of the present invention.

[0063] Figure 27 The illustration shows a method for assigning AIDs to non-AP stations attached to a multi-link device according to an embodiment of the present invention.

[0064] Figure 28The illustration shows a TID-to-link mapping negotiation process in which an AP multi-link device sends a TID-to-link mapping request according to an embodiment of the present invention.

[0065] Figure 29 The illustration shows a TID-to-link mapping negotiation process in which an AP multi-link device sends a TID-to-link mapping request according to an embodiment of the present invention.

[0066] Figure 30 The illustration shows a TID-to-link mapping negotiation process according to an embodiment of the present invention, when the link group requesting the TID-to-link mapping is different from the link group set by the TID-to-link mapping response.

[0067] Figure 31 The illustration shows a method for a non-AP multi-link device to determine services cached on an AP multi-link device according to an embodiment of the present invention. Detailed Implementation

[0068] 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.

[0069] Throughout this specification, when it is stated that an element is "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 more" or "or less" may be appropriately replaced by "greater than" or "less than," respectively.

[0070] In this invention, fields and subfields can be used interchangeably.

[0071] Figure 1 The figure illustrates a wireless LAN system according to an embodiment of the present invention.

[0072] 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 diagram shows the basic structure BSS between them.

[0073] 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 distributed services, and a distributed system (DS) that connects multiple access points (AP-1 and AP-2).

[0074] 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 station 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).

[0075] 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 station 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 communications with multiple wireless communication terminals.

[0076] 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).

[0077] 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.

[0078] 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.

[0079] Figure 3 The illustration is a block diagram showing 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.

[0080] 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.

[0081] 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.

[0082] 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.

[0083] 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.

[0084] 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.

[0085] Figure 4 The illustration shows a block diagram of the configuration of AP200 according to an embodiment of the present invention. (As shown in...) Figure 4 As illustrated in the figure, the AP200 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.

[0086] Reference Figure 4 The AP200 according to the present 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 AP200 may also include multiple communication modules using different frequency bands. That is, AP200 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, AP200 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 AP200. In embodiments of the present invention, communication unit 220 may represent a radio frequency (RF) communication module for processing RF signals.

[0087] 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 an 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.

[0088] Figure 5 This is a diagram illustrating the process of setting up a link between a STA and an AP.

[0089] Reference Figure 5In a broad sense, the link between STA100 and AP200 is set up through three steps: scanning, authentication, and association. First, the scanning step is where STA100 obtains access information from the BSS operated by AP200. Methods for performing the scan include passive scanning, where AP200 obtains information by periodically transmitting beacon messages (S101), and active scanning, where STA100 transmits a probe request to the AP (S103) and obtains access information by receiving a probe response from the AP (S105).

[0090] In the scanning step, STA100, having successfully received wireless access information, performs an authentication step by transmitting an authentication request (S107a) and receiving an authentication response from AP200 (S107b). After performing the authentication step, STA100 performs an association step by transmitting an association request (S109a) and receiving an association response from AP200 (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.

[0091] 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 STA100, and can exist in the physical association with AP200 or as a standalone server.

[0092] Figure 6 This is a diagram illustrating the Carrier Sense Multiple Access (CSMA) / Collision Avoidance (CA) method used in wireless LAN communication.

[0093] Terminals performing wireless LAN communication determine whether a channel is busy by performing carrier sensing before transmitting data. When a wireless signal with a preset strength or greater is sensed, the corresponding channel is determined to be busy, and the terminal delays access to that channel. This process is called Clear Channel Assessment (CCA), and the level at which a 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 sensed on the corresponding channel, or when a wireless signal with a strength less than the CCA threshold is sensed, the channel is determined to be idle.

[0094] 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 after 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 time by a random number determined by the respective terminal, and terminals that have completely exhausted their time slot time attempt to access the corresponding channel. Thus, the interval during which each terminal performs the backoff procedure is called the contention window interval.

[0095] When a specific terminal successfully accesses the channel, it can transmit data through the channel. However, when a terminal attempting access conflicts with another terminal, the conflicting terminals are each assigned a new random number to re-execute the backoff process. According to an embodiment, the newly assigned random number to each terminal can be determined within a range (2*CW), which is twice the range of random numbers previously assigned to the corresponding terminal (contention window CW). Simultaneously, each terminal attempts access again by re-executing the backoff process in the next contention window interval, and in this case, each terminal begins the backoff process from the remaining time slot of the previous contention window interval. In this way, terminals performing wireless LAN communication can avoid mutual conflicts on the specific channel.

[0096] <Examples of various PPDU formats>

[0097] Figure 7The diagram illustrates an example of the format of the PLCP Protocol Data Unit (PPDU) used in each of the various standard generations. Specifically, Figure 7 The illustration in (a) is based on an embodiment of the conventional PPDU format of 802.11a / g. Figure 7 (b) illustrates an embodiment based on the 802.11ax HE PPDU format, 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.

[0098] 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.

[0099] 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 may 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 may only be used in the HE MU PPDU format.

[0100] 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.

[0101] 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.

[0102] 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.

[0103] 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.

[0104] 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. The obtained number of symbols is multiplied by 4 µs (i.e., the length of one symbol), and then the transmission time of L-STF, L-LTF, and L-SIG (20 µs) is added to obtain the length of the corresponding PPDU, i.e., the reception time RXTIME. This can be represented by Equation 1 below.

[0105] [Equation 1]

[0106]

[0107] in this case, This represents the smallest natural number greater than or equal to x. Since the maximum value of the L_LENGTH field is 4095, the length of the PPDU can be set to up to 5.464 ms. Non-traditional terminals transmitting PPDUs should set the L_LENGTH field as shown in Equation 2 below.

[0108] [Equation 2]

[0109]

[0110] 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.

[0111] [Equation 3]

[0112] TXTIME(us) = T L-STF +T L-LTF +T L-SIG +T RL-SIG +T U-SIG +(T EHT-SIG-A )+(T EHT-SIG-B )

[0113] +T EHT-STF +N EHT-LTF ·T EHT-LTF +T DATA

[0114] 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.

[0115] 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 generations of PPDUs including 11be. U-SIG is based on 64FFT 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.

[0116] 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. By adding TXOP to the PHY header, the PPDU can infer the length of the TXOP included therein without having to decode the MPDU, and TXOP has a value of 7 bits or more.

[0117] 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 contains five basic PPDU BW options (BWs, which can be expressed as powers of 20, and can be referred to as basic BWs) for signal notification at 20, 40, 80, 160 (80+80), and 320 (160+160) MHz, as well as various other PPDU BWs configured via preamble punching. After signal notification at 320 MHz, signaling can be performed in some 80 MHz punched types. 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 signaling operations can be performed, and therefore up to 3 signaling operations can be performed in punctured mode. If the BW field is configured with 4 bits, a total of 16 BW signaling operations can be performed, and therefore up to 11 signaling operations can be performed in punctured mode.

[0118] 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.

[0119] 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.

[0120] 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.

[0121] 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 punctured RUs in order to effectively receive the SUPPDU. Therefore, the AP can transmit a SU PPDU that includes information about the punctured RUs among those assigned to the STA (e.g., the RU's puncturing mode, etc.). That is, in the case of SU PPDU, a puncturing mode field can be included in the EHT-SIG field. This puncturing mode field includes information indicating the puncturing mode in a bitmap format, etc., and whether the puncturing mode has been applied. The puncturing mode field can signal the type of discontinuous channel occurring within the bandwidth.

[0122] 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 punctured resources in the allocated bandwidth via the punctured 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.

[0123] To reduce the signaling overhead of the SU PPDU, only a limited number of discontinuous channel types are signaled. Puncture can be performed on each 20MHz sub-channel. Therefore, if puncturing is performed on a BW (such as 80, 160, and 320MHz) with a large number of 20MHz sub-channels, 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.

[0124] 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.

[0125] 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 SU PPDU 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 as 1 bit to signal whether the EHT ER PPDU uses a 20MHz or 10MHz band PPDU.

[0126] 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.

[0127] 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.

[0128] 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.

[0129] Figure 8The diagram in (a) illustrates an example of the EHT SU PPDU format used 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.

[0130] Figure 8 (b) illustrates 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.

[0131] Figure 8 (c) illustrates an example of the EHT MU PPDU format corresponding to EHT PPDUs 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 follow the U-SIG field.

[0132] Figure 8 The diagram (d) illustrates an example of the EHT ERSU PPDU format, 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.

[0133] 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 that allows multiple STAs to simultaneously receive PPDUs transmitted from the AP. The EHT MU PPDU may transmit the sender's and / or receiver's 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.

[0134] 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 type of resource unit partitioning) 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.

[0135] 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 sender, and the user field corresponding to the remaining resource units not used for data transmission may include a pre-configured null STA ID.

[0136] For ease of description, in this specification, the terms "frame" or "MAC frame" may be used interchangeably with "MPDU".

[0137] When a wireless communication device uses multiple links for communication, its communication efficiency can be improved. In this case, a link is a physical path and can consist of a single wireless medium capable of transmitting MAC service data units (MSDUs). For example, if the frequency band of one link is being used by another wireless communication device, the latter can continue communicating through that link. In this way, the wireless communication device can effectively utilize multiple channels. Furthermore, when a wireless communication device uses multiple links simultaneously, the overall throughput can be increased. However, existing wireless LANs are predicated on one wireless communication device using one link. Therefore, a method for operating a wireless LAN using multiple links is needed. (Refer to...) Figures 9 to 26 This describes a wireless communication method for wireless communication devices using multiple links. First, refer to... Figure 9 Describe the specific form of a wireless communication device that uses multiple links.

[0138] Figure 9 The illustration shows a multi-link device according to an embodiment of the present invention.

[0139] A multi-link device (MLD) can be defined for use in the aforementioned wireless communication methods employing multiple links. A multi-link device can represent a device with one or more affiliated stations. According to a specific embodiment, a multi-link device can represent a device with two or more affiliated stations. Furthermore, the multi-link device can exchange multi-link elements. Multi-link elements include information about one or more stations or one or more links. Multi-link elements can include multi-link setup elements, which will be described later. In this case, the multi-link device can be a logical entity. Specifically, a multi-link device can have multiple affiliated stations. The multi-link device can be referred to as a multi-link logical entity (MLLE) or a multi-link entity (MLE). The multi-link device can have a medium access control service access point (SAP) to the logical link control (LLC). Additionally, the MLD can have a MAC data service.

[0140] Multiple stations included in a multi-link device can operate on multiple links. Furthermore, multiple stations included in a multi-link device can operate on multiple channels. Specifically, multiple stations included in a multi-link device can operate on multiple different links or multiple different channels. For example, multiple stations included in a multi-link device can operate on multiple different channels in 2.4 GHz, 5 GHz, and 6 GHz.

[0141] The operation of a multi-link device can be referred to as multi-link operation, MLD operation, or multi-band operation. Furthermore, if the station attached to the multi-link device is an AP (Access Point), the multi-link device can be called an AP MLD. Conversely, if the station attached to the multi-link device is a non-AP station, the multi-link device can be called a non-AP MLD.

[0142] Figure 9The diagram illustrates the communication operation between non-AP MLD and AP-MLD. Specifically, both non-AP MLD and AP-MLD use three links for communication. AP MLD includes a first AP (AP1), a second AP (AP2), and a third AP (AP3). Non-AP MLD includes a first non-AP STA (non-AP STA1), a second non-AP STA (non-AP STA2), and a third non-AP STA (non-AP STA3). The first AP (AP1) and the first non-AP STA (non-AP STA1) communicate via the first link (Link1). Furthermore, the second AP (AP2) and the second non-AP STA (non-AP STA2) communicate via the second link (Link2). Finally, the third AP (AP3) and the third non-AP STA (non-AP STA3) communicate via the third link (Link3).

[0143] Multilink operation may include a multilink setup operation. Multilink setup corresponds to the association operation of the aforementioned single-link operation and may need to be performed first for frame switching in the multilink. The multilink device can obtain the information required for multilink setup from the multilink setup element. Specifically, the multilink setup element may include capability information related to the multilink. In this case, the capability information may include information indicating whether one of the multiple devices included in the multilink device can perform reception while one of them is performing transmission. Furthermore, the capability information may include information about the links that can be used by each station included in the MLD. Additionally, the capability information may include information about the channels that can be used by each station included in the MLD.

[0144] Multi-link configuration can be achieved through negotiation between peer stations. Specifically, multi-link configuration can be performed through communication between stations without needing to communicate with the AP. Furthermore, multi-link configuration can be performed using any single link. For example, even when configuring multi-link configuration from the first to the third link, the configuration can still be performed using the first link.

[0145] Furthermore, a mapping between traffic identifiers (TIDs) and links can be configured. Specifically, frames corresponding to a specific TID value can be exchanged only through pre-specified links. The mapping between TIDs and links can be configured directionally. For example, when multiple links are configured between a first multi-link device and a second multi-link device, the first multi-link device can be configured to send frames with the first TID on the first link among the multiple links, and the second multi-link device can be configured to send frames with the second TID on the first link. Additionally, there may be default settings for the mapping between TIDs and links. Specifically, if no additional settings are configured in the multi-link setup, the multi-link devices can exchange frames corresponding to TIDs on each link according to the default settings. In this case, the default setting could be exchanging all TIDs on a single link.

[0146] TIDs will be described in detail. A TID is an ID used to classify services and data to support Quality of Service (QoS). Furthermore, TIDs can be used or assigned at layers higher than the MAC layer. Additionally, a TID can represent a traffic category (TC) or a traffic stream (TS). Furthermore, there are 16 different TID types. For example, a TID can be specified as one of 0 to 15. The TID value used can be specified differently depending on the access policy, channel access, or medium access method. For example, when using enhanced distributed channel access (EDCA) or hybrid coordination function contention based channel access (HCAF), a TID can be assigned a value from 0 to 7. When using EDCA, a TID can represent user priority (UP). In this case, UP can be specified based on TC or TS. UPs can be assigned at layers higher than the MAC layer. Furthermore, when using HCF controlled channel access (HCCA) or SPCA, TID can be assigned a value from 8 to 15. If HCCA or SPCA is used, TID can represent TSID. Additionally, if HEMM or SEMM is used, TID can be assigned a value from 8 to 15. If HEMM or SEMM is used, TID can represent TSID.

[0147] UP and AC can be mapped to each other. AC can be a label used in EDCA to provide QoS. AC can also be a label used to indicate an EDCA parameter set. EDCA parameters or EDCA parameter sets are parameters used in EDCA channel contention. QoS stations can use AC to ensure QoS. Furthermore, AC can include AC_BK, AC_BE, AC_VI, and AC_VO. AC_BK, AC_BE, AC_VI, and AC_VO can represent background, best effort, video, and voice, respectively. Furthermore, AC_BK, AC_BE, AC_VI, and AC_VO can be further subdivided. For example, AC_VI can be subdivided into primary AC_VI and backup AC_VI. Similarly, AC_VO can be subdivided into primary AC_VO and backup AC_VO. Additionally, UP or TID can be mapped to AC. For example, UP or TID 1, 2, 0, 3, 4, 5, 6, and 7 can be mapped to AC_BK, AC_BK, AC_BE, AC_BE, AC_VI, AC_VI, AC_VO, and AC_VO, respectively. Furthermore, UP or TID 1, 2, 0, 3, 4, 5, 6, and 7 can be mapped to AC_BK, AC_BK, AC_BE, AC_BE, spare AC_VI, primary AC_VI, primary AC_VO, and spare AC_VO, respectively. Additionally, UP or TID 1, 2, 0, 3, 4, 5, 6, and 7 can have increasing priorities in sequence. That is, "1" can be a low priority, while "7" can be a high priority. Therefore, the priorities can increase in the order of AC_BK, AC_BE, AC_VI, and AC_VO. Furthermore, AC_BK, AC_BE, AC_VI, and AC_VO can correspond to AC indexes (ACI) 0, 1, 2, and 3, respectively. Due to these characteristics of TIDs, the mapping between TIDs and links can represent the mapping between ACs and links. Furthermore, the mapping between links and ACs can represent the mapping between TIDs and links.

[0148] As mentioned above, a TID can be mapped to each of multiple links. Mapping can mean specifying a link capable of exchanging the corresponding service for a TID or AC. Furthermore, it's possible to specify which TIDs or ACs can be sent within a link for each transmission direction. As mentioned above, there can be default settings for the mapping between TIDs and links. Specifically, if no additional settings are made in the multi-link setup, the multi-link device can exchange frames corresponding to the TIDs on each link according to the default settings. In this case, the default setting could be exchanging all TIDs on a single link. At any given time, any TID or AC can be mapped to at least one link. Management frames and control frames can be transmitted on all links.

[0149] When a link is mapped to a TID or AC, only data frames corresponding to the TID or AC mapped to that link can be transmitted on that link. Therefore, if a link is mapped to a TID or AC, frames that do not correspond to the TID or AC mapped to that link cannot be transmitted on that link. If a link is mapped to a TID or AC, an ACK can also be sent based on the link to which the TID or AC is mapped. For example, a block ACK agreement can be determined based on the mapping between the TID and the link. In another specific embodiment, the mapping between the TID and the link can be determined based on the block ACK agreement. Specifically, a block ACK agreement can be set for a TID mapped to a specific link.

[0150] QoS can be ensured through the mapping between TIDs and links. Specifically, high-priority ACs or TIDs can be mapped to links with a relatively small number of operating stations or with good channel conditions. Furthermore, this mapping allows stations to maintain a power-saving state for longer periods.

[0151] Figure 10 The illustration shows a multi-link mapping method based on a TID-to-link mapping method according to an embodiment of the present invention.

[0152] Reference Figure 10 , as reference Figure 9 As described above, a mapping relationship can exist between TIDs and links. Furthermore, in this invention, the mapping relationship between TIDs and links can be referred to as TID-to-link mapping, TID-to-link mapping, TID mapping, link mapping, etc. A TID can be a traffic identifier. Additionally, a TID can be an identifier (ID) used to classify services, data, etc., to support quality of service (QoS).

[0153] Furthermore, TID can be an ID used or assigned in a layer higher than the MAC layer. TID can represent traffic categories (TC) and traffic streams (TS). Furthermore, TID can have 16 values, for example, it can be represented by values ​​from 0 to 15. Additionally, different TID values ​​can be used depending on the access policy, channel access, and medium access method. For example, when using EDCA (hybrid coordination function (HCF) contention-based channel access, enhanced distributed channel access), possible TID values ​​can be 0 to 7. Furthermore, when using EDCA, the TID value can represent user priority (UP), and this UP can be a value related to TC or TS. Furthermore, UP can be a value assigned in a layer higher than MAC. Furthermore, when using HCCA (HCF controlled channel access) or SPCA, possible TID values ​​can be 8 to 15. Furthermore, when using HCCA or SPCA, TID can represent TSID. Furthermore, when using HEMM or SEMM, the TID value can be between 8 and 15. Additionally, when using HEMM or SEMM, TID can represent TSID.

[0154] Furthermore, a mapping relationship can exist between UP and access category (AC). An AC can be a label indicating the provision of QoS in EDCA, or a label indicating a set of EDCA parameters. EDCA parameters or sets of EDCA parameters can be used for channel connectivity. ACs can be used by QoS STAs.

[0155] The AC value can be set to one of AC_BK, AC_BE, AC_VI, and AC_VO. AC_BK, AC_BE, AC_VI, and AC_VO can represent background, best effort, video, and voice, respectively. Furthermore, AC_BK, AC_BE, AC_VI, and AC_VO can be subdivided. For example, AC_VI can be subdivided into primary AC_VI and alternate AC_VI. Similarly, AC_VO can be subdivided into primary AC_VO and alternate AC_VO. Additionally, UP values ​​or TID values ​​can be mapped to AC values. For example, UP values ​​or TID values ​​1, 2, 0, 3, 4, 5, 6, and 7 can be mapped to AC_BK, AC_BK, AC_BE, AC_BE, AC_VI, AC_VI, AC_VO, and AC_VO, respectively. Alternatively, the UP values ​​or TID values ​​1, 2, 0, 3, 4, 5, 6, and 7 can be mapped to AC_BK, AC_BK, AC_BE, AC_BE, standby AC_VI, primary AC_VI, primary AC_VO, and standby AC_VO, respectively. Furthermore, the UP values ​​or TID values ​​1, 2, 0, 3, 4, 5, 6, and 7 can have increasing priorities in sequence. That is, "1" can be a low priority, while "7" can be a high priority. Therefore, the priorities can increase in the order of AC_BK, AC_BE, AC_VI, and AC_VO. Additionally, AC_BK, AC_BE, AC_VI, and AC_VO can correspond to AC indices (ACI) 0, 1, 2, and 3, respectively.

[0156] Therefore, a relationship can exist between TID and AC. Thus, the TID-to-link mapping of this invention can also be a mapping relationship between AC and link. Furthermore, in this invention, "TID being mapped" can mean that AC is mapped, and vice versa.

[0157] According to embodiments of the present invention, TIDs can be mapped to each link in a multi-link network. For example, a mapping can exist regarding which links a particular TID or AC is allowed to transmit and receive on. Furthermore, this mapping can be defined separately for each of the two directions of the link. Additionally, as mentioned above, the mapping between TIDs and links can have a default configuration. For example, the mapping between TIDs and links can essentially map all TIDs to a certain link. Furthermore, according to embodiments, at a specific point in time, a particular TID or AC can be mapped to at least one link. Moreover, management frames or control frames can be transmitted on all links.

[0158] In this invention, data frames corresponding to a TID or AC mapped for a specific direction of the link can be sent. However, data frames corresponding to a TID or AC not mapped for a specific direction of the link cannot be sent.

[0159] According to embodiments, TID-to-link mapping can also be applied to acknowledgment. For example, a block ack agreement can be based on TID-to-link mapping. Alternatively, TID-to-link mapping can be based on a block ack agreement. For example, a block ack agreement can exist for TIDs in a TID-to-link mapping.

[0160] QoS services can be provided through TID-to-link mapping. For example, data for a given AC or TID can be transmitted quickly by mapping it to a link with good channel conditions or fewer STAs. Alternatively, TID-to-link mapping can enable STAs on a specific link to save power (or enter a doze state).

[0161] Reference Figure 10 An AP MLD can exist that includes AP1 and AP2. Additionally, a non-AP MLD can exist that includes STA1 and STA2. Furthermore, Link 1 and Link 2, as multiple links, can exist within an AP MLD. AP1 and STA1 can be associated on Link 1, and AP2 and STA2 can be associated on Link 2.

[0162] Therefore, Link 1 may include a link transmitting from AP1 to STA1 and / or a link transmitting from STA1 to AP1, and Link 2 may include a link transmitting from AP2 to STA2 and / or a link transmitting from STA2 to AP2. In this case, TID and / or AC can be mapped to each link.

[0163] For example, all TIDs and all ACs can be mapped to links in Link 1 that transmit from AP1 to STA1 and links in Link 1 that transmit from STA1 to AP1. Furthermore, only AC_VO or the TID corresponding to AC_VO can be mapped to links in Link 2 that transmit from STA2 to AP2. Additionally, only data for mapped TIDs and / or ACs can be transmitted through the corresponding links. Furthermore, data for TIDs or ACs not mapped to a link cannot be transmitted on the corresponding link.

[0164] Figure 11 The illustration shows a power management operation performed by a station according to an embodiment of the present invention.

[0165] According to embodiments of the present invention, the station can operate in a power-saving (PS) mode. In this mode, the station can switch between an awake state and a doze state. In the awake state, the station operates at full power. Furthermore, in the awake state, the station can perform transmission and reception. In the doze state, transmission and reception can be restricted. If frames to be transmitted in the power-saving mode are buffered on the station, the station can switch to the awake state and otherwise operate in the doze state. In power-saving mode, the station may frequently switch between the awake and doze states. In active mode, the station always remains capable of transmission and reception. That is, in active mode, the station can always operate in the awake state.

[0166] In this way, when the station is operating in power-saving mode, the station in power-saving mode may not be able to perform reception. Therefore, the AP can perform transmission by signaling to the station that it has buffered the service to be transmitted and receiving a response from the station. For ease of explanation, "the AP signaling to the station that it has buffered the service to be transmitted" is called a traffic indication. Furthermore, the signaling used for traffic indication is called traffic indication signaling. Traffic indication between the AP and the station can be performed as follows. In this specification, the service can include any one of frames, BUs, MSDUs, and MPDUs.

[0167] If an AP has buffered traffic awaiting transmission to a station, the AP can send a traffic indication signaling message indicating that the buffered traffic awaiting transmission to the station is buffered. In this specification, the traffic indication signaling message can indicate buffered traffic depending on the context, and is not limited to traffic for a specific station. The traffic indication signaling message can include at least one of a traffic indication map (TIM) element and a multi-link traffic element. The traffic indication signaling message can be in bitmap format. Specifically, the traffic indication signaling message can indicate whether the traffic corresponding to each bit of the bitmap is buffered on the AP that sent the bitmap. Furthermore, the traffic indication signaling message can indicate the recipient of the buffered traffic. For example, the traffic indication signaling message can indicate that the buffered traffic corresponds to at least one of group-addressed traffic, multicast traffic, broadcast traffic, and individually addressed traffic. The bitmap can signal which group and station the traffic corresponds to based on the position of the bits in the bitmap. Based on the position of the bits in the bitmap, a station can determine whether traffic corresponding to a group including the station is buffered on the AP or whether traffic for the station is buffered on the AP.

[0168] Service indication (SID) signaling can be transmitted based on a pre-specified time point. Therefore, a station in power-saving mode can switch from power-saving mode to wake-up mode based on the transmission time of the SID signaling. SID signaling can be included in beacon frames. Furthermore, SID signaling can be included in TIM frames. Additionally, the AP can periodically transmit SID signaling. Specifically, the AP can transmit SID signaling based on the target beacon transmission time (TBTT). However, if the channel is not idle (occupied) during the TBTT, the AP can transmit SID signaling at a time point later than the TBTT. Stations can receive SID signaling by remaining in wake-up mode during the TBTT. Beacon frames containing SID signaling may not be transmitted precisely during the TBTT. Therefore, stations can remain in wake-up mode for a certain period including the TBTT time point.

[0169] In the foregoing embodiments, a scenario was described where an AP sends a service indication signaling message and a station receives the service indication signaling message. In this case, the station can be a non-AP station. Furthermore, the AP can be included in an AP multi-link device, and the non-AP station can be included in a non-AP multi-link device. Additionally, the aforementioned service can refer to a bufferable unit (BU) or a cached BU.

[0170] Before sending group addressing or broadcast services, a delivery TIM (DTIM) can be sent. A DTIM is a type of TIM that indicates whether group addressing and broadcast services are buffered on the AP. A beacon frame containing a DTIM can be called a DTIM beacon frame. If a station receives a DTIM indicating that it is sending group services for a group that includes that station, the station can send signaling to the AP indicating that it will receive the group services.

[0171] A station receiving a service instruction signaling message can send signaling to initiate (retrieve) a transmission for the station. This signaling can be at least one of a PS-Poll frame or a U-APSD trigger frame. The AP receiving the signaling to initiate (retrieve) a transmission for the station sends the buffered service to the station.

[0172] exist Figure 11In this process, the first AP (AP1) includes the TIM (Time Indicator Memo) in the beacon frame and sends the beacon frame in each TBTT (Total Time To Watch). The TIM sent by the first AP (AP1) indicates that the service for the first STA1 (STA1) is buffered. The first STA1 sends a PS-polling frame and remains awake to receive services. The first AP (AP1) sends the buffered services (data destined for STA1) to the first STA1. The first STA1 can receive the buffered services and enter a power-saving state. Furthermore, the first STA1 can remain awake while sending the next TIM.

[0173] In addition, Figure 11 In this configuration, the first AP (AP1) sends a DTIM (Digital Transmission Information Meter) every three beacon frames. Therefore, the DTIM interval is three beacon frames. During this process, the first station (STA1), operating in power-saving mode, remains awake whenever a DTIM is sent. After sending the DTIM beacon, the first AP (AP1) sends broadcast or group-addressed services. When a DTIM indicates that a broadcast or group-addressed service to be received by the first station (STA1) is buffered, the first station (STA1) remains awake to receive the broadcast or group-addressed service. In this way, even in power-saving mode, the first station (STA1) can reliably receive broadcast or group-addressed services. Figure 12 This describes the format of TIM elements that can be included in business instruction signaling.

[0174] Figure 12 The illustration shows the format of a TIM element according to an embodiment of the present invention.

[0175] The TIM element includes the aforementioned TIM. A TIM element may include at least one of the following: Element ID subfield, Length subfield, DTIM Count subfield, DTIM Period subfield, Bitmap Control subfield, and Partial Virtual Bitmap subfield. The lengths of the Element ID subfield, Length subfield, DTIM Count subfield, DTIM Period subfield, and Bitmap Control subfield are 1 octet or 8 bits. The Partial Virtual Bitmap subfield may have a variable length of up to 251 octets. The length of the Partial Virtual Bitmap subfield may be determined by the Bitmap Control field or the Bitmap Offset subfield of the Bitmap Control field.

[0176] The Element ID subfield indicates the ID of the element that includes the Element ID subfield.

[0177] The length subfield indicates the length of the element that includes the length subfield. Specifically, the length subfield can indicate the length of an element other than the element ID subfield and the length subfield.

[0178] The DTIM count subfield indicates how many beacon frames will be sent before the next DTIM. Specifically, the value of the DTIM count subfield can indicate how many beacon frames, including those containing the DTIM count subfield, will be sent before the next DTIM. For example, if the value of the DTIM count subfield is 0, it can indicate that the DTIM count subfield is included in the DTIM beacon.

[0179] The DTIM Periodicity subfield indicates the number of beacon frames sent between DTIMs. If all TIMs are DTIMs, the value of the DTIM Periodicity subfield is set to 1.

[0180] The bitmap control subfield can include a Traffic Indicator subfield and a Bitmap Offset subfield. The Traffic Indicator subfield can be a 1-bit field, and the Bitmap Offset subfield can be a 7-bit field. The Traffic Indicator subfield indicates whether group-addressed traffic is cached. Specifically, if group-addressed traffic is cached, the AP can set the value of the Traffic Indicator subfield to 1. Group-addressed traffic can be traffic with a receiver AID of 0. The Bitmap Offset subfield indicates the starting point of the bits in the Traffic indication virtual bitmap that correspond to the Partial Virtual Bitmap. The association ID (AID) corresponding to the Partial Virtual Bitmap is determined based on the Bitmap Offset subfield.

[0181] Each bit in the Partial Virtual Bitmap field indicates whether the service to be sent to the station with the corresponding AID is cached on the sending AP of the TIM. If a bit in the Partial Virtual Bitmap field is 1, it indicates that the service to be sent to the station with the corresponding AID is cached on the sending AP of the TIM. If a bit in the Partial Virtual Bitmap field is 0, it indicates that the service to be sent to the station with the corresponding AID is not cached on the sending AP of the TIM. Therefore, if a bit in the Partial Virtual Bitmap field is 1, the receiving station can determine that the service to be sent to the station with the corresponding AID is cached on the sending AP of the TIM. If a bit in the Partial Virtual Bitmap field is 0, the receiving station can determine that the service to be sent to the station with the corresponding AID is not cached on the sending AP of the TIM. Furthermore, the station that receives the TIM can determine that the service to be sent to the station whose AID is not indicated by a partial virtual bitmap is not cached on the AP that sent the TIM.

[0182] A TIM element may include a Service Indication Virtual Bitmap subfield. In this case, the bit number in the Service Indication Virtual Bitmap subfield can indicate the AID of the station corresponding to that bit. Specifically, the bit with bit number n in the Service Indication Virtual Bitmap subfield indicates whether a frame to be sent to the station with AID n is cached on the AP sending the TIM element. Specifically, if the bit number in the Service Indication Virtual Bitmap subfield is N, then that bit can indicate whether services to be sent to the station with AID N or the group with Group ID N are cached on the AP sending the TIM. A TIM may include a partial virtual bitmap subfield instead of a Service Indication Virtual Bitmap subfield. A partial virtual bitmap subfield is equivalent to omitting consecutive bits with a value of 0 from the Service Indication Virtual Bitmap subfield. A partial virtual bitmap subfield can be equivalent to omitting the first or last consecutive bit in a group of consecutive bits with a value of 0 from the Service Indication Virtual Bitmap subfield. Specifically, a partial virtual bitmap subfield can be the bits with octet numbers N1 to N2 in the Service Indication Virtual Bitmap subfield. N1 can be the largest even number in the service indicator virtual bitmap subfield where all bit numbers from 1 to (N1*8-1) are 0. N2 can be the smallest number in the service indicator virtual bitmap subfield where all bit numbers from (N2+1)*8 to 2007 are 0. This may be a method for configuring some virtual bitmap subfields when multiple BSSID sets are not supported (i.e., when dot11MultiBSSIDImplemented is false). In this specification, the bit number n of the bitmap or subfield refers to the (n+1)th bit among the bits of the bitmap or subfield.

[0183] If all bits in the virtual bitmap subfield of the business instruction are 0 except for the bit with bit number 0, then the length of the partial virtual bitmap subfield is 1 octet, and the value of all bits in the partial virtual bitmap subfield can be set to 0. In this case, the value of the bitmap offset field can be 0, and the value of the length field can be set to 4.

[0184] Furthermore, if all bits in the Business Indication Virtual Bitmap subfield and all bits in the Bitmap Control subfield are 0, the TIM element may not include a portion of the Virtual Bitmap field and the Bitmap Control field. In this case, the length field can be set to 2. Thus, a Bitmap Control field can exist even when a portion of the Virtual Bitmap field is present in the TIM.

[0185] When multiple BSSID sets are supported, i.e., when dot11MultiBSSIDImplemented is True, the method for configuring partial virtual bitmap subfields can be performed according to the following embodiment. When using multiple BSSID sets, management frames sent from the AP corresponding to the transmitted BSSID can include information for the BSS corresponding to the nontransmitted BSSID. In this case, the management frame can include at least one of a beacon frame and a probe response frame. The TIM element of the beacon frame sent from the transmitted BSSID can indicate whether the AP corresponding to the nontransmitted BSSID included in the multiple BSSID set including the transmitted BSSID buffers the frame. With this in mind, the method for configuring partial virtual bitmap subfields will be described below.

[0186] Assuming the maximum number of BSSIDs that a multi-BSSID set can have is n, bits 1 to (2^n-1) of the Service Indication Virtual Bitmap subfield can indicate whether a group-addressed frame is cached on the AP sending the TIM element. In this case, the group-addressed frame can be a frame cached on the AP corresponding to a non-transmitting BSSID. Therefore, the group-addressed frame is a group-addressed frame of the AP or BSS corresponding to a non-transmitting BSSID. Each bit 1 to (2^n-1) of the Service Indication Virtual Bitmap subfield can indicate whether a frame is cached on the AP corresponding to each bit. In this case, bits with bit numbers greater than (2^n-1) in the Service Indication Virtual Bitmap subfield indicate whether a frame to be sent to the station with AID n is cached on the AP sending the TIM element. Therefore, the AP may not assign bits 1 to (2^n-1) as AIDs. In this embodiment, the bits corresponding to inactive non-transmitting BSSIDs can be set as reserved bits. At this point, the reserved bit value can be set to 0. Furthermore, the AP can assign a value equal to or greater than 2^n as the station's AID. Specifically, the AP can assign values ​​between 2^n and 2007 as the station's AID. The EHT AP may not assign 2007 as an AID. This range of assignable AIDs is called the AID space. Transmit BSSIDs and non-transmit BSSIDs can share the same AID space. In a specific embodiment, the EHT AP may not assign 2007 as the station's AID.

[0187] The maximum number of BSSIDs a multi-BSSID set can have can be signaled through the multi-BSSID element. n can be the value indicated by the MaxBSSID indicator of the multi-BSSID element.

[0188] A configuration method for the partial virtual bitmap subfield will be described below. The configuration method for the partial virtual bitmap subfield may vary depending on the function related to the multiple BSSID set of the AP that transmits the TIM element. A non-S1G AP may configure the partial virtual bitmap subfield through method A or method B. In addition, an S1G AP may configure the partial virtual bitmap subfield through method C. Non-HT APs, HT APs, VHT APs, HE APs and EHT APs may all be non-S1G APs. An S1G AP refers to an AP that operates in a frequency band below 1 GHz, and a non-S1G AP refers to an AP that operates in a frequency band above 1 GHz.

[0189] First, method A will be described. The partial virtual bitmap subfield may consist of bits from octet number 0 to N2 of the traffic indication virtual bitmap. N2 is the smallest number among all numbers that satisfy the condition that all bits from bit number (N2+1)*8 to 2007 in the traffic indication virtual bitmap are 0. If no N2 satisfying this condition exists, N2 is 250. In method A, the value of the bitmap offset field is 0. In addition, the value of the length field is N2+4.

[0190] Method B will be described. The partial virtual bitmap subfield may consist of bits from octet number 0 to (N0-1) of the traffic indication virtual bitmap and bits from octet number N1 to N2 of the traffic indication virtual bitmap. N0 may be the maximum positive integer that satisfies (N0*8-2^n<8). If N0 is an odd number, N1 is greater than N0 and is the maximum even number that satisfies the condition that all bits from bit number N0*8 to (N1*8-1) are 0. If no value of N1 greater than N0 exists, N1 may be N0. In addition, N2 is the smallest positive integer that satisfies the condition that all bits from bit number (N2+1)*8 to 2007 in the traffic indication virtual bitmap are 0. If no N2 satisfying this condition exists, N2 may be 250. In method B, the value of the bitmap offset field is (N1-N0) / 2. In addition, the value of the length field is (N0+N2-N1+4). If there is no buffered frame on any BSS corresponding to a transmitting BSS and a non-transmitting BSS, the length of the partial virtual bitmap subfield is 1 octet, and all bits in the partial virtual bitmap subfield may be set to 0. At this time, the value of the bitmap offset field is 0. In addition, the value of the Length field is 4.

[0191] When no individually addressed frames are cached on any BSS corresponding to the transport BSSID and non-transport BSSID, and group addressed frames are cached on one or more BSSs, a portion of the virtual bitmap subfield may consist of eight bits numbered from 0 to (N0-1). N0 is the largest positive integer satisfying (N0*8-2^n)<8.

[0192] It may be necessary to instruct the cached traffic on each of the multiple links operated by the multi-link device. This will be achieved through... Figures 13 to 18 Describe it.

[0193] Figure 13 The illustration shows the format of a multi-link traffic element according to an embodiment of the present invention.

[0194] APs operating in a multi-link device can share an AID space. Specifically, a multi-link device can have only one AID space. In this case, when referring to... Figure 12 When a TIM element indicates a frame cached on an AP, the station may have difficulty determining which link the frame is cached on. A service indication signaling method is needed to address this problem. Specifically, a multi-link device can execute service indication signaling on a link-by-link basis. In a specific embodiment, the multi-link device can execute service indication signaling for each station attached to it. The TIM element sent by the multi-link device can indicate whether a cached frame exists on each of the multiple links operated by the multi-link device. In this case, the TIM element sent by the multi-link device is called a multi-link service element.

[0195] Multilink devices can transmit multilink service elements via beacon frames or TIM frames. Furthermore, multilink service elements can be included in frames that also contain TIM elements.

[0196] exist Figure 13 In this context, a multi-link traffic element may include an element ID subfield, a length subfield, an element ID extension subfield, a multi-link traffic control subfield, and a per-link traffic indication list subfield.

[0197] The element ID subfield is an octet field that indicates the ID of the element that includes the element ID subfield.

[0198] The length subfield is an octet field that indicates the length of the element including the length subfield. Specifically, the length subfield can indicate the length of the element other than the element ID subfield and the length subfield.

[0199] The Element ID extended subfield is an octet field, and is combined with the value of the Element ID subfield, which includes the Element ID extended subfield, to indicate the value used to identify the element.

[0200] The multi-link service control subfield is an octet field and includes a bitmap size subfield and an AID offset subfield. The bitmap size subfield is a 4-bit subfield that indicates the size of each link service indicator bitmap subfield. If the bitmap size value is M, the size of each link service indicator bitmap subfield can be M+1. A bitmap size value of 0 is a reserved value.

[0201] The AID offset subfield is an 11-bit subfield that indicates the starting position of the bits in the service indication virtual bitmap indicated by each link service indication list or each link service indication bitmap subfield. Therefore, the AID (Associated ID) corresponding to each link service indication list or each link service indication bitmap subfield is determined based on the AID offset subfield. If the AID offset value is K, then each link service indication list or each link service indication bitmap subfield indicates from bit number K of the service indication virtual bitmap. Furthermore, if the AID offset subfield value is K, then the minimum value among the AIDs corresponding to each link service indication list or each link service indication bitmap subfield is K. Each link service indication list subfield is a variable-length field and may include one or more link service indication bitmap subfields. If the AID offset subfield value is K, then each link service indication bitmap subfield indicates from bit number K of the service indication virtual bitmap. The number of each link service indication bitmap subfield included in each link service indication list subfield can be the number of bits set to 1 in the bits corresponding to the AID of the non-AP multi-link device in the partial virtual bitmap. Multiple link service indication bitmap subfields can be arranged according to the AID corresponding to each link service indication bitmap subfield in each link service indication list subfield. Specifically, multiple link service indication bitmap subfields can be arranged in ascending order according to the AID corresponding to each link service indication bitmap subfield in each link service indication list subfield.

[0202] If the value of the bitmap size field is m, then the size of each link service indicator bitmap subfield is m+1 bits. If the TID-to-link mapping negotiation is successful, the bits in each link service indicator bitmap subfield indicate whether the service to be sent to a non-AP station operating on the link corresponding to that bit is cached. Specifically, when the value of a bit in each link service indicator bitmap subfield is 1, the bits in each link service indicator bitmap subfield can indicate that the service to be sent to a non-AP station operating on the link corresponding to that bit is cached. If the value of a bit in each link service indicator bitmap subfield is 0, the bits in each link service indicator bitmap subfield can indicate whether the service to be sent to a non-AP station operating on the link corresponding to that bit is not cached. If the TID-to-link mapping is the default mapping, the bits in each link service indicator bitmap subfield can indicate whether it is recommended to request (retrieve) the transmission of cached services on the link corresponding to that bit. Specifically, when the value of a bit in each link service indication bitmap subfield is 1, the bit in each link service indication bitmap subfield can indicate the recommended transmission of cached services on the link corresponding to that bit. If the TID-to-link mapping of a link corresponds to the default mapping, uplink and downlink transmissions on that link can be performed without TID restrictions. Furthermore, the default mapping applies to links where TID-to-link mapping negotiation was not successfully performed. Therefore, successful TID-to-link mapping negotiation can indicate the case where TID-to-link mapping negotiation was successfully performed and all TIDs were not mapped to all links.

[0203] In each link service indication bitmap subfield, the bits are mapped to links based on their bit numbers. Specifically, in each link service indication bitmap subfield, the bit corresponding to bit number n can be mapped to the link with link ID n. Furthermore, each link service indication list subfield may include a padding field. Therefore, each link service indication list subfield can have a length in octets. The padding field can have a length between 0 and 7 bits.

[0204] AP multilink devices can send frames that include both multilink service elements and TIM elements. In this case, the frame can be a beacon frame. (See reference...) Figure 14 This describes a method for AP multi-link devices to signal services cached on the AP multi-link device using multi-link service elements and TIM elements.

[0205] Figure 14 The illustration shows a method according to an embodiment of the present invention for signaling services cached on an AP multilink device through partial virtual bitmap subfields of multilink service elements and TIM elements.

[0206] In the TIM element sent by the AP multi-link device, bits corresponding to non-AP multi-link devices in certain virtual bitmap subfields or service indication virtual bitmaps can be set to 1. At this time, the non-AP multi-link device can parse the multi-link service element. Based on the service indication bitmap subfields corresponding to the non-AP multi-link device in each link of the multi-link service element, the non-AP multi-link device can determine on which link it is recommended to request (retrieve) the transmission of cached services, or determine on which link the service is cached. (See reference...) Figure 13 As described, when TID-to-link mapping negotiation is successfully performed, a non-AP multi-link device can determine whether a service to be sent to a station of the non-AP multi-link device operating on the link corresponding to that bit is cached based on the value of the bit in the service indication bitmap subfield corresponding to the non-AP multi-link device. Furthermore, when the TID-to-link mapping is the default mapping, the non-AP multi-link device can instruct the AP multi-link device whether to recommend requesting the transmission of cached services on the link corresponding to that bit, based on the value of the bit in the service indication bitmap subfield corresponding to the non-AP multi-link device.

[0207] A non-AP multi-link device can request the transmission of cached services from an AP multi-link device on the links corresponding to the bits set to 1 in the service indication bitmap subfields of the links corresponding to the non-AP multi-link device. Specifically, if the TID-to-link mapping negotiation is successfully performed, the non-AP multi-link device can request the transmission of cached services from the AP multi-link device on the links corresponding to the bits set to 1 in the service indication bitmap subfields of the links corresponding to the non-AP multi-link device. If the TID-to-link mapping is the default mapping, the non-AP multi-link device can request the transmission of cached services from the AP multi-link device on one or more links, including the links corresponding to the bits set to 1 in the service indication bitmap subfields of the links corresponding to the non-AP multi-link device. In these embodiments, the non-AP multi-link device can request the transmission of services cached on the AP multi-link device by sending a U-APSD trigger frame or a PS-polling frame. When a request for the transmission of cached services is received, the AP multi-link device can send the cached services to the non-AP multi-link device. Furthermore, when a request for transmission of cached services is received, the AP multi-link device can send a QoS empty frame instead of the cached service.

[0208] exist Figure 14In this embodiment, legacy stations prior to EHT, or stations whose TID-to-link mapping is set to the default mapping, are assigned a value less than K as their AID value. Non-AP stations that successfully negotiated the TID-to-link mapping are assigned a value equal to or greater than K as their AID value. Figure 14 In the service indication virtual bitmap, all bits with bit numbers less than (N-1)*8 are set to 0. Therefore, the AP multilink device will not cache services for stations with AIDs less than (N-1)*8. In the bits corresponding to bit numbers of (N-1)*8 or greater, at least one bit is set to 1. N-1 is an even number, and N*8 is the value of k. Therefore, bits starting from bit number (N-1)*8 in the service indication virtual bitmap are included in the partial virtual bitmap subfield. At this time, the value of the bitmap offset subfield of the partial virtual bitmap subfield is set to (N-1) / 2. Furthermore, the bits in the partial virtual bitmap subfield corresponding to AIDs of (N-1)*8, (N-1)*8+2, (N-1)*8+3, k, k+2, and k+3 are set to 1.

[0209] As described above, the AID offset subfield of a multi-link service element can indicate the AID of the multi-link device corresponding to the first of the link service indication bitmap subfields in each link service indication bitmap subfield of the multi-link service element. Figure 14 In this context, the value of the AID offset subfield is set to K. Multi-link service elements include individual link service indication bitmap subfields corresponding to multi-link devices where a portion of the virtual bitmap subfield indicates 1. Figure 14 In this context, the multi-link service element includes a link service indication bitmap subfield for each of the stations or non-AP multi-link devices whose AIDs correspond to k, k+2, and k+3. At this time, the link service indication bitmap subfields are arranged in ascending order according to the AID.

[0210] The value of the bitmap size field of the multi-link service element is 2. Therefore, each link service indicator bitmap subfield of the multi-link service element includes 3 bits. At this time, the first bit B0 of each link service indicator bitmap subfield is mapped to the link with link ID 0, the second bit B1 is mapped to the link with link ID 1, and the third bit B2 is mapped to the link with link ID 2.

[0211] As described above, the multi-link device with AID value corresponding to K uses the default mapping, while the multi-link devices with AID values ​​corresponding to K+2 and K+3 successfully performed TID-to-link mapping. Therefore, the link service indication bitmap subfields corresponding to AID K indicate that it is recommended to request the transmission of cached services on the link with link ID 1. Furthermore, the link service indication bitmap subfields corresponding to AID K+2 indicate that the AP multi-link device is caching services on both links with link ID 1 and link ID 2. In this case, the services cached on the link with link ID 1 and the services cached on the link with link ID 2 can be the same or different. Additionally, the link service indication bitmap subfields corresponding to AID K+3 indicate that the AP multi-link device is caching services on the link with link ID 1.

[0212] However, it cannot be guaranteed that the AIDs of non-AP multi-link devices connected to the AP multi-link device will be assigned consecutively. Furthermore, the AIDs of non-AP stations not included in the multi-link device may be assigned to AIDs among the AIDs of the non-AP multi-link devices. In this case, the non-AP multi-link device may have difficulty determining which AID belongs to a station not included in the non-AP multi-link device. Therefore, if the multi-link service element does not include the individual link service bitmap subfields for stations not included in the non-AP multi-link device, the non-AP multi-link device may have difficulty parsing the individual link service bitmap subfields. For example, in... Figure 14 In this embodiment, AID K+1 is assigned to a non-AP multi-link device, and the value of the bit corresponding to AID K+1 in a partial virtual bitmap subfield of the TIM element can be 1. In this case, a non-AP multi-link device with AID K+2 or K+3 may not be able to determine which of the three link service bitmap subfields is used for the corresponding non-AP multi-link. Therefore, a method for setting multi-link service elements is needed to solve this problem. This will be achieved through... Figure 15 To describe.

[0213] Figure 15 The figure illustrates a method for setting up multi-link service elements according to an embodiment of the present invention.

[0214] In embodiments of the present invention, the AP multi-link device may include in the multi-link service element each link service bitmap subfield for non-AP stations not included in the multi-link device. Specifically, even for non-AP stations not included in the multi-link device, if the value of a bit in the service indication bitmap subfield or a partial virtual bitmap subfield corresponding to that non-AP station is 1, the AP multi-link device may include in the multi-link service element each link service bitmap subfield for the non-AP station. Therefore, the AP multi-link device may include in the multi-link service element each link service bitmap subfield for all stations corresponding to the bits of the service indication bitmap subfield or the partial virtual bitmap subfield that are set to 1. For ease of explanation, the station corresponding to the bits of the service indication bitmap subfield or the partial virtual bitmap subfield that are set to 1 is referred to as the station pointed to by the cached service.

[0215] At this point, the AP multi-link device can include each link service bitmap subfield in the multi-link service element for all stations pointed to by the cache service, regardless of whether the station pointed to by the cache service is attached to the multi-link device, corresponds to a non-AP multi-link device, or is attached to any AP or BSS. The AP or BSS to which the station pointed to by the cache service is attached can indicate whether the station pointed to by the cache service belongs to a multi-BSSID set.

[0216] AP multi-link devices can include as many link service bitmap subfields in the multi-link service element as the number of stations to which the cached service points. The method for setting the link service bitmap subfields corresponding to stations not attached to the multi-link device will be described.

[0217] An AP multi-link device can set all bits of the link service bitmap subfields corresponding to stations not attached to the multi-link device to 0. That is, the AP multi-link device can set the bits of the link service bitmap subfields corresponding to stations not attached to the multi-link device to reserved fields. In another specific embodiment, the AP multi-link device can set the bits of the link service bitmap subfields corresponding to stations not attached to the multi-link device to arbitrary values. In another specific embodiment, the AP multi-link device can set the bits of the link service bitmap subfields corresponding to stations not attached to the multi-link device to 1. In this case, non-AP multi-link devices can ignore the bits of the link service bitmap subfields corresponding to stations not attached to the multi-link device. In another specific embodiment, the AP multi-link device can set the bits of the link service bitmap subfields corresponding to stations not attached to the multi-link device to 1. In another specific embodiment, the AP multi-link device sets the bits of each link service bitmap subfield corresponding to the link operated by the station not attached to the multi-link device to 1, and sets the remaining bits to 0.

[0218] exist Figure 15 In the embodiments, the settings of the service indication virtual bitmap and the settings of some virtual bitmap subfields can be combined with... Figure 14 The settings for the business instruction virtual bitmap are the same as the settings for some virtual bitmap subfields. However, in Figure 15 In this embodiment, AID k and AID k+3 correspond to non-AP multi-link devices. AID k+2 corresponds to a station not included in the multi-link device. The link service bitmap subfields corresponding to AID k and AID k+3 of the multi-link service element are as follows: Figure 14 The configuration is as described in the previous embodiment. Since AID K+2 is a station not included in the multi-link device, all bits in the link service bitmap subfield corresponding to AID k+2 in the multi-link service element are set to 0.

[0219] The AID offset subfield of a multi-link service element can indicate the bits following all bits corresponding to the group ID and group addressing frame in the bits of the service indication virtual bitmap and the bits of the partial virtual bitmap subfield. In this case, the group ID can include the AID value 0. Furthermore, the group ID can include the bit number of the service indication virtual bitmap corresponding to the multiple BSSID set, i.e., the AID corresponding to the bit number. Additionally, the group ID can include the bit number of the service indication virtual bitmap corresponding to the transport BSSID and non-transport BSSID, i.e., the AID corresponding to the bit number. When the maximum possible number of BSSIDs in a multiple BSSID set is 2^n, the group ID can include values ​​corresponding to AID 0 to (2^n-1). When using a multiple BSSID set and the maximum possible number of BSSIDs in a multiple BSSID set is 2^n, the AID offset subfield can indicate the value following the value corresponding to AID 0 to (2^n-1). The reason for setting the AID offset field in this way is that since group-addressed frames are not limited to transmission over a specific link, it may not be very meaningful to signal for each link.

[0220] According to another embodiment of the present invention, even if the AID offset subfield indicates the bits preceding the bit indicating the group ID in the bits of the service indication virtual bitmap and the bits of the partial virtual bitmap subfield, the link service indication bitmap subfields corresponding to the group ID may not be included in the multi-link service element. Even if the AID offset subfield indicates the bits preceding the bit indicating the group ID in the bits of the service indication virtual bitmap and the bits of the partial virtual bitmap subfield, the multi-link service element may only include the link service indication bitmap subfields corresponding to individual stations among the stations pointed to by the cached service. Specifically, when the maximum number of BSSIDs that can be set to multiple BSSID sets is 2^n, the AID offset subfield may indicate the bits corresponding to AIDs of (2^n-1) or less in the bits of the service indication virtual bitmap and the bits of the partial virtual bitmap subfield. In this case, the multi-link service element may only include the link service indication bitmaps corresponding to the bits set to 1 in the bits of the service indication virtual bitmap and the bits of the partial virtual bitmap subfields corresponding to AID 2^n. The station receiving the multi-link service element can determine that the multi-link service element only includes the service indication bitmap of each link, which is the bit set to 1 in the bits of the service indication virtual bitmap and the bits of some virtual bitmap subfields that correspond to AID 2^n.

[0221] According to another embodiment of the present invention, a multi-link service element may include each link service indication bitmap corresponding to each of all bits that are set to 1 after the bits indicated by the AID offset subfield in the service indication virtual bitmap and the partial virtual bitmap subfield, regardless of whether the AID offset subfield indicates the bits before the bits indicating the group ID in the bits of the service indication virtual bitmap and the partial virtual bitmap subfield. In this case, the AP multi-link device may set the values ​​of all link service indication bitmap fields corresponding to the bits of the service indication virtual bitmap and the partial virtual bitmap subfield corresponding to the group address to a predetermined value. The predetermined value may be 0. In another specific embodiment, the AP multi-link device may set the values ​​of all link service indication bitmap fields corresponding to the bits of the service indication virtual bitmap and the partial virtual bitmap subfield corresponding to the group address to arbitrary values. The AP multi-link device may set the bits corresponding to the link in which the group addressing frame is transmitted to 1 in the bits of all link service indication bitmap fields corresponding to the bits of the service indication virtual bitmap and the partial virtual bitmap subfield corresponding to the group address to 0.

[0222] Figure 16 The illustration illustrates a method for setting the per-link traffic bitmap subfields of a multi-link service element when the link set operated by the AP multi-link device is different from the link set operated by the non-AP multi-link device communicating with the AP multi-link device.

[0223] The link groups operated by an AP multi-link device and the link groups operated by non-AP multi-link devices communicating with it can be different. For example, an AP multi-link device can communicate with a first non-AP multi-link device on links one through three, and it can communicate with a second non-AP multi-link device on links one through two. In this case, there may be issues with the method of setting the sub-fields of the link service bitmap for each multi-link service element.

[0224] Even if the link group operated by the AP multi-link device is different from the link group operated by the non-AP multi-link device communicating with the AP multi-link device, the AP can still set the size of all the link service indicator bitmap subfields included in the multi-link service element to be the same, and can set the link mapped to each bit of all the link service indicator bitmap subfields to be the same. Specifically, the AP multi-link device can set the number of bits of all the link service indicator bitmap subfields included in the multi-link service element to be greater than the number of links set by the AP multi-link device. This is because the multiple link IDs set by the AP multi-link device may not start from 0 or the IDs of multiple links may not be consecutive. For example, the AP multi-link device can set the number of bits of all the link service indicator bitmap subfields included in the multi-link service element to the maximum number of links that the AP multi-link device can set. In another specific embodiment, the AP multi-link device can set the number of bits of all the link service indicator bitmap subfields included in the multi-link service element to the value of the maximum link ID that the AP multi-link device can set plus 1.

[0225] The method for setting the bit values ​​of links not configured by the AP multi-link device and the corresponding service indication bitmap subfields of links not configured by the non-AP multi-link device may have problems. For ease of explanation, the bits of links not configured by the AP multi-link device and the corresponding service indication bitmap subfields of links not configured by the non-AP multi-link device are referred to as no-link bits. The AP multi-link device can set the value of the no-link bit to a predetermined value. Therefore, the AP multi-link device can set the bits of the service indication bitmap subfields corresponding to links not configured by the AP multi-link device or non-AP multi-link devices to a predetermined value. In this case, the predetermined value can be 0. In another specific embodiment, the AP multi-link device can set the value of the no-link bit to any value. In this case, non-AP stations can ignore the value of the no-link bit.

[0226] Furthermore, the values ​​of the bits in the link service indication bitmap subfields corresponding to disabled links can be reserved. Specifically, the values ​​of the bits in the link service indication bitmap subfields corresponding to disabled links can be set to 0. In this case, a disabled link can be a link in which uplink and downlink transmissions are suspended. Specifically, a disabled link can be a link in which uplink and downlink transmissions of a single addressed frame are suspended. In this case, non-AP stations can ignore the value of the undisabled bit.

[0227] exist Figure 16 In the embodiments, such as Figure 16As shown in (a), the AP multi-link device AP MLD operates on the first link Link0 to the third link Link2. The first multi-link device MLD1 and the AP MLD set the first link Link0 to the third link Link2. The second multi-link device MLD2 and the AP MLD set the first link Link0 to the second link Link1. The AP MLD sets the number of bits in each link bitmap subfield of the multi-link service element to 3 bits. The multi-link service element sent by the AP MLD includes each link bitmap subfield corresponding to each of the first multi-link device MLD1, the first station STA1, and the second multi-link device MLD2. The AP MLD operates according to a reference... Figure 14 and Figure 15 The described embodiment sets the values ​​of each link bitmap subfield corresponding to the first multi-link device MLD1. Furthermore, the AP multi-link device AP MLD is configured according to a reference... Figure 15 The described embodiment sets the values ​​of each link bitmap subfield corresponding to the first station STA1. The AP multi-link device AP MLD is based on the reference... Figure 14 and Figure 15 The described embodiment sets the values ​​of the first bit B0 to the second bit B1 of each link bitmap subfield corresponding to the second multi-link device MLD2. Furthermore, the AP multi-link device AP MLD sets the value of the third bit B2 of each link bitmap subfield corresponding to the second multi-link device MLD2 to 0, i.e., a predetermined value, as described above.

[0228] In the foregoing embodiments, the bit number of each bit in the link service indication bitmap subfield and the ID of the link corresponding to that bit are described as the same. According to a specific embodiment, the bit number of each bit in the link service indication bitmap subfield and the ID of the link corresponding to that bit may be different. The link IDs of the links set by the AP multi-link device that sends each link service indication bitmap subfield can be mapped in ascending order to the bit numbers of the bits in each link service indication bitmap subfield. The AP multi-link device can set a link with ID 1 and a link with ID 3, and each link service indication bitmap subfield can be a 2-bit field. In this case, the first bit B0 of each link service indication bitmap subfield is mapped to the link with ID 1, and the second bit B1 is mapped to the link with ID 3.

[0229] Figure 17 The illustration shows a method for determining the links indicated by the service bitmap subfields of each link based on the TID-to-link mapping according to an embodiment of the present invention.

[0230] As described above, if the TID-to-link mapping negotiation is successfully executed, the bits in each link service indication bitmap subfield indicate whether the service to be sent to a non-AP station operating on the link corresponding to that bit is cached. Specifically, when the value of a bit in each link service indication bitmap subfield is 1, the bits in each link service indication bitmap subfield can indicate that the service to be sent to a non-AP station operating on the link corresponding to that bit is cached. When the value of a bit in each link service indication bitmap subfield is 0, the bits in each link service indication bitmap subfield can indicate that the service to be sent to a non-AP station operating on the link corresponding to that bit is not cached. If the TID-to-link mapping is the default mapping, the bits in each link service indication bitmap subfield can indicate whether it is recommended to request (obtain) cached service transmission on the link corresponding to that bit. Specifically, when the value of a bit in each link service indication bitmap subfield is 1, the bits in each link service indication bitmap subfield can indicate that it is recommended to request cached service transmission on the link corresponding to that bit. If a link's TID-to-link mapping corresponds to the default mapping, uplink and downlink transmissions on that link can be performed without TID restrictions. Furthermore, the default mapping applies to links where TID-to-link mapping negotiation failed or where TID-to-link mapping negotiation was teardown.

[0231] The aforementioned successful execution of TID-to-link mapping negotiation indicates that TID-to-link mapping is applied instead of the default mapping. Furthermore, as mentioned above, TID-to-link mapping can be applied individually for each transmission direction. Therefore, in the aforementioned embodiments, successful execution of TID-to-link mapping negotiation indicates successful execution of TID-to-link mapping negotiation for downlink transmission. Furthermore, the application of the default mapping indicates that the TID-to-link mapping used for downlink transmission is the default mapping.

[0232] exist Figure 17In this embodiment, the AP multi-link device AP MLD and the non-AP multi-link device (non-AP MLD1) successfully performed TID-to-link mapping negotiation. The AP multi-link device AP MLD and the non-AP multi-link device (non-AP MLD1) mapped TID value 0 to uplink transmission on the first link Link0. Furthermore, the AP multi-link device AP MLD and the non-AP multi-link device (non-AP MLD1) mapped TID values ​​1 to 7 to uplink transmission on the second link Link1. At this time, the AP multi-link device AP MLD and the non-AP multi-link device (non-AP MLD1) applied default mappings for downlink transmission on the first link Link0 and downlink transmission on the second link Link1. Therefore, if the value of a bit in the link service indication bitmap subfield sent by the AP multi-link device AP MLD is 1, the non-AP multi-link device (non-AP MLD1) determines that the AP multi-link device AP MLD recommends that the non-AP multi-link device (non-AP MLD1) request service transmission on the link corresponding to the bit set to 1. Because... Figure 17 In (a), the value of the bit corresponding to the second link Link1 in each link service indication bitmap subfield is 1, so the non-AP multi-link device (non-AP MLD1) is determined to be recommended to request service transmission on the second link Link1.

[0233] Figure 17 (b) illustrates the TID-to-link mapping element used in TID-to-link mapping negotiation. Multilink devices may include the TID-to-link mapping element in the (re)association request frame, (re)association response frame, TID-to-link mapping request frame, and TID-to-link mapping response frame. When a multilink device requests TID-to-link mapping, it may include the TID-to-link mapping element in either the (re)association request frame or the TID-to-link mapping request frame. When a multilink device responds to a TID-to-link mapping request, it may include the TID-to-link mapping element in either the (re)association response frame or the TID-to-link mapping response frame.

[0234] The TID-to-Link Mapping element includes an Element ID subfield, a Length subfield, an Element ID Extension subfield, a TID-to-Link MappingControl subfield, and seven Link Mapping subfields corresponding to TIDs 0 through 7. The TID-to-Link MappingControl subfield may include a Direction subfield, a Default LinkMapping subfield, a Reserved subfield, and a Link Mapping PresenceIndicator subfield. The Direction subfield indicates which transmission direction the mapping is applied to. The Direction subfield can represent at least one of downlink, uplink, and bidirectional link. The Default LinkMapping subfield indicates whether the TID-to-Link Mapping element, including the Default LinkMapping subfield, is used in TID-to-Link Mapping negotiation to apply the default mapping. Specifically, the default link mapping subfield can indicate whether a TID-to-link mapping element including the default link mapping subfield is used for TID-to-link mapping negotiation to apply the default mapping to the transmission direction indicated by the direction subfield.

[0235] Each bit of the Link Map Existence Indicator subfield indicates whether the corresponding Link Map subfield is included in the TID-to-Link Map element. Each bit of the Link Map Existence Indicator subfield can be mapped to a Link Map subfield of a TID with the same value as the bit index. That is, the nth bit Bn-1 of the Link Map Existence Indicator subfield can be mapped to the Link Map subfield corresponding to TID n-1. The Link Map subfield indicates the TID corresponding to it is the object of the TID-to-Link Map negotiation performed by the TID-to-Link Map element.

[0236] Figure 18 The illustration shows a method for setting the link service indication bitmap subfields of a multi-link service element by an AP multi-link device according to another embodiment of the present invention.

[0237] In reference Figure 16In the described embodiments, the multi-link service element includes each link service indicator bitmap subfield for the station to which the cache service is pointed, regardless of whether the station to which the cache service is pointed is included in the multi-link device. In another embodiment of the invention, the multi-link service element may include each link service indicator bitmap subfield for some of the stations to which the cache service is pointed, and may not include each link service indicator bitmap subfield for the remaining stations to which the cache service is pointed. In this case, the station to which the cache service is pointed may be limited to the station to which the cache service is pointed after the bit corresponding to the AID indicated by the AID offset subfield. Specifically, if the station to which the cache service is pointed is not included in the multi-link device, the AP multi-link device may not include each link service indicator bitmap subfield for the station to which the cache service is pointed in the multi-link service element. In this way, the length of the multi-link service element can be prevented from becoming too long.

[0238] In another specific embodiment, the AP multi-link device may exclude the link service indicator bitmap subfields for stations after a specific bit position within the station pointed to by the cached service from the multi-link service element. The station receiving the multi-link service element can determine the last link service indicator bitmap subfield included in the multi-link service element based on the length subfield of the multi-link service element. Therefore, even if the link service indicator bitmap subfields for stations after a specific bit position within the station pointed to by the cached service are not included in the multi-link service element, the station receiving the multi-link service element can still parse the multi-link service element normally. In this embodiment, the AP multi-link device may assign a smaller value to the AID of stations included in the multi-link device than the AID of stations not included in the multi-link device.

[0239] exist Figure 18 In this embodiment, the AID offset of the multi-link service element indicates the AID value K. The stations pointed to by cached services with AID greater than K are not included in the two multi-link devices with AIDs K and K+2, nor in the multi-link devices with AIDs K+6 and K+7. The multi-link service element includes a bitmap subfield for each link service indication bitmap used by the two multi-link devices with AIDs K and K+2.

[0240] In another specific embodiment, a multi-link service element may include an AID offset 2 subfield. The station receiving the multi-link service element can parse each link service indicator bitmap subfield of the multi-link service element based on the AID offset 2 subfield. The AID offset 2 subfield can indicate which AID corresponds to each of the last link service indicator bitmap subfields of the multi-link service element. In this case, the AID offset 2 subfield can represent all AID values. In another specific embodiment, the AID offset 2 subfield can indicate the maximum value of the AID that can correspond to each of the last link service indicator bitmap subfields.

[0241] In another specific embodiment, the AID offset 2 subfield can indicate the AID corresponding to each of the last link service indication bitmap subfields in a preset number of units. For example, when the value of the AID offset 2 subfield is n, the AID offset 2 subfield can indicate the AID corresponding to each of the last link service indication bitmap subfields as 2^N. Here, N is an integer. In this embodiment, the AID offset 2 subfield can have a length of (11-N) bits.

[0242] When the value of the AID offset 2 subfield is n, the AID offset 2 subfield can indicate an AID value of 2^N*n. Here, n is an integer. For example, the AID can be indicated in units of 8 bits. In this case, the AID offset 2 subfield can have a length of 8 bits. In this embodiment, the AID offset 2 subfield can indicate AIDs such as 8, 16, 24, and 32. Therefore, the length of the AID offset 2 subfield can be defined as less than 11 bits.

[0243] In another specific embodiment, the AID offset 2 subfield can indicate the AID in the same unit as the AID offset subfield. In this way, the number of bits occupied by the AID offset 2 subfield and the AID offset subfield can be reduced.

[0244] In the foregoing embodiments, a frame may include multiple multi-link service elements. Specifically, the AP multi-link device may generate multi-link service elements including link service indication bitmaps for one or more multi-link devices corresponding to AID values ​​within the range of: from the first AID in an AID list arranged in ascending order according to the AID values ​​of the station pointed to by the cached service, starting with the AID before the AID corresponding to the station not included in the multi-link device, to the excluded AIDs thereafter. At this time, AIDs up to the excluded AIDs are removed from the AID list, and the AP multi-link device generates multi-link service elements including multi-link service indication bitmaps for one or more multi-link devices corresponding to the new excluded AIDs in the AID list. The AP multi-link device may repeat this operation until the end of the AID list to additionally generate multi-link service elements including link service indication bitmaps for one or more multi-link devices. In this way, even if there are AIDs not included in the multi-link devices among the AIDs of the multi-link devices, the multi-link service element can include the link service indicator bitmap subfields for each link device, but not the link service indicator bitmap subfields not included in the multi-link devices.

[0245] In this embodiment, a non-AP multi-link device can ignore multi-link service elements that do not include the link service indication bitmap sub-fields corresponding to the AID of the non-AP multi-link device. The non-AP multi-link device can determine whether a multi-link service element includes the link service indication bitmap sub-fields corresponding to the AID of the non-AP multi-link device based on at least one of the values ​​of the AID offset sub-field and the length sub-field. The non-AP multi-link device can also determine whether a multi-link service element includes the link service indication bitmap sub-fields corresponding to the AID of the non-AP multi-link device based on at least one of the values ​​of the AID offset sub-field and the AID offset 2 sub-field.

[0246] Furthermore, in the aforementioned embodiments, if the non-AP multi-link device is not the station to which the cache service is directed, the non-AP multi-link device can ignore the multi-link service element.

[0247] Will pass Figures 19 to 21 This describes the method used to determine the AID space. First, referencing... Figure 19 Describe the EHT operation elements.

[0248] Figure 19 The figure illustrates an EHT operation element according to an embodiment of the present invention.

[0249] Figure 19 (a) shows the format of EHT operation elements, while Figure 19 (b) illustrates the EHT Operation Parameters field. EHT operation elements may include an Operation Parameters field. The Operation Parameters field can be a 1-byte field. EHT operation elements may also include an EHT Operation Information field. The EHT Operation Information field can be 0, 3, or 5 byte fields. The EHT Operation Information field may include either an EHT Operation Information field or a Disabled Subchannel Bitmap field.

[0250] The EHT operation parameter fields may include the EHT Operation Information Present subfield, the Disabled Subchannel Bitmap Present subfield, the Group Addressed BU Indication Limit subfield, and the Group Addressed BU Indication Exponent subfield. The EHT Operation Information Present subfield, the Disabled Subchannel Bitmap Present subfield, the Group Addressed BU Indication Limit subfield, and the Group Addressed BU Indication Exponent subfield are all 1-bit fields.

[0251] The EHT operation information presence subfield indicates whether an EHT operation element includes an EHT operation information subfield. If the value of the EHT operation information presence subfield is 0, the EHT operation element may not include the EHT operation information subfield. That is, when the EHT operation information presence subfield is set to 0, the length of the EHT operation information subfield can be 0 octets. If the value of the EHT operation information presence subfield is 1, the EHT operation element may include the EHT operation information field. In this case, the length of the EHT operation information subfield can be 3 or 5 octets.

[0252] The Disabled Subchannel Bitmap Presence subfield indicates whether the EHT Operation Information field includes this subfield. If the value of the Disabled Subchannel Bitmap Presence subfield is 0, the EHT Operation Information subfield may not include it. In this case, the size of the EHT Operation Information subfield can be 3 octets. If the value of the Disabled Subchannel Bitmap Presence subfield is 1, the EHT Operation Information subfield may include it. In this case, the size of the EHT Operation Information subfield can be 5 octets.

[0253] The Group Addressing BU Indication Limitation subfield can indicate whether there are buffered group addressing frames for other APs attached to AP multilink devices that share the same non-transmitting BSSID as all APs in the multi-BSSID set, and whether there are limitations when indicated in the TIM element. The specific method for setting the Group Addressing BU Indication Limitation subfield is as follows.

[0254] The Group Addressing BU Indicator Restriction subfield may be set to 0 if at least one of the following conditions is met; otherwise, the Group Addressing BU Indicator Restriction subfield may be set to 1.

[0255] -Condition 1. The AP (the AP that sends the EHT operation element) does not belong to the multi-BSSID set.

[0256] - Condition 2. The AP (the AP that sends EHT operation elements, the AP that sends beacon frames, or the AP corresponding to the transport BSSID) belongs to a multi-BSSID set, and the number of bits required to indicate whether there is a buffered group addressing frame corresponding to all other APs of the AP multilink device that are all non-transport BSSIDs is no more than 48 bits.

[0257] In addition, the Group Addressing BU Indicator Index subfield can indicate the number of bits (N) of the buffered group addressing frames that will be used to indicate the other APs corresponding to the multilink device corresponding to each non-transmitter BSSID. The value of N will be explained further below.

[0258] Furthermore, the 48 bits mentioned above can be replaced by other numbers of bits. Therefore, the number of bits in the bitmap used to indicate group addressing services for other APs attached to the same multi-link device as the AP that does not transmit the BSSID in the service indication virtual bitmap can be changed. In this invention, 48 bits or other bit numbers can be referred to as "bitmap limits".

[0259] Figure 20 The illustration shows a virtual bitmap of service instructions according to an embodiment of the present invention.

[0260] The service indication virtual bitmap can indicate group-addressed services corresponding to APs on multi-link devices with the same transmission BSSID or APs on multi-link devices without the same transmission BSSID. A station receiving the service indication virtual bitmap can determine whether a group-addressed service is cached on the AP (or BSS) associated with the station. Furthermore, the station can use this bitmap to receive cached group-addressed services.

[0261] In an embodiment of the present invention, in the service indication virtual bitmap, the bit for group addressing services is located at the front, and the bit for services individually addressing stations or multi-link devices can be located after the bit for group addressing services.

[0262] An AP sending a TIM element can indicate buffered group-addressed frames corresponding to other APs in a multi-link device to which it is attached. The buffered group-addressed frames corresponding to other APs in a multi-link device to which the AP is attached can be indicated using the TIM element, a partial virtual bitmap subfield, or N bits following the last bit in the Service Indication Virtual Bitmap used to indicate a non-transmitting BSSID. If the AP does not belong to a multi-BSSID set, the buffered group-addressed frames corresponding to other APs in a multi-link device to which the AP is attached can be indicated using the TIM element, a partial virtual bitmap subfield, or N bits starting from the first bit B0 of the Service Indication Virtual Bitmap. In this case, the N bits are mapped according to the link ID order, and each of the N bits indicates whether a group-addressed frame is buffered on the link mapped to that bit.

[0263] Bits X through X+N-1 of the partial virtual bitmap subfield or service indication virtual bitmap can indicate the group addressing frame corresponding to the reporting AP (or, if the AP belongs to a multiple BSSID set, the AP corresponding to the transmitting BSSID) and other APs attached to the multi-link device to which the reporting AP belongs. In this case, the reporting AP refers to the AP that sends the TIM element. Furthermore, X-1 can be the last bit in the TIM element, the partial virtual bitmap subfield, or the service indication virtual bitmap used to indicate a non-transmitting BSSID. If a multiple BSSID set is not used, X-1 can be 0. Additionally, N can be the N previously mentioned in the description of EHT operation elements. Specifically, if the AP sending the TIM element does not belong to a multiple BSSID set, X-1 can be 0. Furthermore, N can be the N previously mentioned in the description of EHT operation elements. The value of N can be determined based on the group addressing BU indication index subfield. The value of N can be 2^(the value of the group addressing BU indication index subfield + 1) - 1. In other words, if the value of the group addressing BU indicator subfield is 1, then the value of N can be 2^(1+1)-1. That is, the value of N can be 3. Furthermore, the N bits from bit X to X+N-1 can indicate whether the group addressing service used for each link is cached in ascending order of link ID. Of the N bits, the first n bits can indicate the group addressing frames corresponding to other APs in the AP multi-link device to which the AP is attached, while the remaining bits can be set to 0.

[0264] The last bit indicating a non-transmitting BSSID in the TIM element, a partial virtual bitmap subfield, or a service indication virtual bitmap can be determined based on the theoretical maximum number of BSSIDs in the multiple BSSID set. When the theoretical maximum number of BSSIDs in the multiple BSSID set is 2^n, AID1 to (2^n-1) are reserved for non-transmitting BSSIDs, and the last bit indicating a non-transmitting BSSID in the TIM element, a partial virtual bitmap subfield, or a service indication virtual bitmap can correspond to AID(2^n-1). Therefore, starting from bit 2^n in the TIM element, a partial virtual bitmap subfield, or a service indication virtual bitmap, a group addressing frame can be indicated on other APs of the multi-link device to which the transmitting BSSID AP (reporting AP) is attached.

[0265] In another specific embodiment of the invention, the last bit indicating a non-transmitting BSSID in the TIM element, a partial virtual bitmap subfield, or a service indication virtual bitmap can be determined based on the actual bits used as the non-transmitting BSSID. If the maximum number of non-transmitting BSSIDs that are actually unused, equivalent to the maximum possible number of BSSIDs in a set of multiple BSSIDs, is actually used, then it may be the last bit among the bits in the TIM element, the partial virtual bitmap subfield, or the service indication virtual bitmap corresponding to the actually used non-transmitting BSSIDs.

[0266] exist Figure 20 In this configuration, a portion of the service indication virtual bitmap is used to configure a partial virtual bitmap subfield. Each bit in the service indication virtual bitmap and the partial virtual bitmap subfield indicates whether a cached service exists to be sent to the station with the AID corresponding to that bit. At this point, the bit number of the bits in the service indication virtual bitmap and the partial virtual bitmap subfield can be mapped to an AID value. Figure 20 In this embodiment, the first bit B0 of the service indication virtual bitmap is mapped to the transmission BSSID. In another specific embodiment, the first bit B0 of the service indication virtual bitmap can be mapped to the reporting AP (the AP sending the TIM element). That is, if the reporting AP belongs to a multi-BSSID set, the first bit B0 of the service indication virtual bitmap is mapped to either the reporting AP or the transmission BSSID. If the reporting AP does not belong to a multi-BSSID set, the first bit B0 of the service indication virtual bitmap is mapped to the reporting AP. The cached service corresponding to the AP can be a group-addressed service.

[0267] exist Figure 20In this embodiment, bits B1 to B3 of the service indication virtual bitmap are mapped to a non-transmitting BSSID. In this case, the aforementioned (X-1) is 3. Furthermore, bits B4 to B6 of the service indication virtual bitmap can correspond to other APs attached to the AP multilink device to which the reporting AP or the transmitting BSSID belongs. That is, in this case, the value of the group addressing BU indication index subfield is 1. Therefore, N is 3.

[0268] The reporting AP can use the last bit (i.e., BX+N-1) of the TIM element, a partial virtual bitmap subfield, or the N bits in the service indication virtual bitmap that indicate whether group-addressed frames corresponding to other APs in the AP MLD with the same transmission BSSID are cached, to indicate whether group-addressed frames corresponding to other APs in the AP multilink device to which each non-transmission BSSID is attached are cached. Specifically, to indicate the group-addressed frames corresponding to other APs in the AP multilink device to which the k-th non-transmission BSSID is attached, the reporting AP can use the k-th N bits after the last bit (i.e., BX+N-1) of the TIM element, a partial virtual bitmap subfield, or the service indication virtual bitmap that indicate whether group-addressed frames are cached on the link corresponding to the AP MLD to which the transmission BSSID is attached. In this case, the N bits corresponding to each non-transmission BSSID are mapped to N links in link ID order, and each of the N bits indicates whether a group-addressed frame is cached on the link corresponding to that bit.

[0269] The bits in the virtual bitmap subfield of the report section or the service indication virtual bitmap, from bit number Y+(k-1)*N to bit number Y+k*N-1, can indicate whether group addressing frames corresponding to other APs in the AP multilink device attached to the AP that is not transmitting BSSID are cached. This embodiment only applies to the case where the bit number is less than a pre-specified bit number. A predetermined value can be determined based on the bitmap limit. The predetermined value can be Y+(bitmap limit). In this case, k in the k-th non-transmitting BSSID can start from 1. Y-1 can be the last bit used to indicate whether the group addressing frame corresponding to the AP multilink device attached to the AP that corresponds to the transmitting BSSID is cached. That is, Y-1 can be the same value as X+N-1. In addition, N can be the N mentioned in the aforementioned EHT operation element related embodiments. N can be determined based on the group addressing BU indication index subfield. N can be 2^(the value of the group addressing BU indication index subfield + 1)-1. Furthermore, in TIM elements, partial virtual bitmap subfields, or service indication virtual bitmaps, N bits numbered Y+(k-1)*N to Y+k*N-1 are mapped to N links in link ID order, and each of the N bits indicates whether a group addressing frame is cached on the link corresponding to that bit. Of the N bits, the first n bits can indicate whether a group addressing frame corresponding to other APs in the AP multilink device attached to the AP attached to the k-th non-transmitting BSSID is cached, while the remaining bits can be set to 0.

[0270] exist Figure 20 In this context, Y is 7 and N is 3. Therefore, in the TIM element, partial virtual bitmap subfield, or service indication virtual bitmap, bit numbers 7+(k-1)*3 to 7+k*3-1 can indicate the group addressing frames corresponding to other APs in the AP multilink device attached to the AP corresponding to the k-th non-transmitting BSSID. That is, bit numbers 7 to 9 in the TIM element, partial virtual bitmap subfield, or service indication virtual bitmap indicate the group addressing frames corresponding to other APs in the AP multilink device attached to the AP corresponding to the first non-transmitting BSSID. Furthermore, the k-th non-transmitting BSSID can be the non-transmitting BSSID corresponding to AID k.

[0271] The service indication virtual bitmap and partial virtual bitmap subfields may include portions corresponding to the reporting AP (or, if the reporting AP belongs to a multi-BSSID set, the transmission BSSID), portions corresponding to non-transmission BSSIDs (if the reporting AP belongs to a multi-BSSID set), portions corresponding to other APs attached to the AP multi-link device to which the reporting AP is attached, portions corresponding to other APs attached to the AP multi-link device to which the non-transmission BSSID is attached (if the reporting AP belongs to a multi-BSSID set), and portions corresponding to group-addressed frames. Furthermore, the order in which the various portions are included in the service indication virtual bitmap and partial virtual bitmap subfields may be the same as the order mentioned above.

[0272] according to Figure 14 In the embodiments described, the value of the AID offset subfield may not indicate the portion of the Service Indication Virtual Bitmap and Partial Virtual Bitmap subfields corresponding to the Group ID and Group Addressing Frame. That is, the value of the AID offset subfield may indicate a value greater than the maximum value corresponding to the Group ID and Group Addressing Frame in the Service Indication Virtual Bitmap and Partial Virtual Bitmap subfields. Alternatively, the value of the AID offset subfield may indicate an individually addressed frame in the Service Indication Virtual Bitmap and Partial Virtual Bitmap subfields. Alternatively, the AID offset subfield value may indicate the value corresponding to a non-AP station or non-AP multi-link device in the Service Indication Virtual Bitmap and Partial Virtual Bitmap subfields.

[0273] More specifically, in Figure 14 In the embodiments described, in order to prevent the value of the AID offset subfield from indicating the portion of the service indication virtual bitmap and partial virtual bitmap subfield corresponding to the group-addressed frame, the value of the AID offset subfield can be determined based on the maximum number of BSSIDs in the multiple BSSID set. According to Figures 19 to 20 In this embodiment, the value of the AID offset subfield can be determined by taking additional factors into consideration. This is because the service indication virtual bitmap and partial virtual bitmap subfields have more bits to indicate group-addressed frames compared to the maximum number of BSSIDs that can be included in a multi-BSSID set.

[0274] According to embodiments of the present invention, the range of values ​​that the AID offset subfield can indicate can be determined based on the number of bits required to indicate the group addressing frames corresponding to other APs in the AP multilink device to which the AP corresponding to the transmitted BSSID or non-transmitted BSSID is attached. For example, the range of values ​​that the AID offset subfield can indicate can be determined based on the maximum number of BSSIDs that can be included in the aforementioned multiple BSSID set, and the number of bits required to indicate the group addressing frames corresponding to other APs in the AP multilink device to which the AP corresponding to the transmitted BSSID or non-transmitted BSSID is attached. Furthermore, the range of values ​​that the AID offset subfield can indicate can be determined based on the maximum number of BSSIDs that can be included in the multiple BSSID set, the number of bits required to indicate the group addressing frames corresponding to other APs in the AP multilink device to which the AP corresponding to the transmitted BSSID or non-transmitted BSSID is attached, and bitmap limits.

[0275] According to embodiments of the present invention, the AID offset subfield may be disallowed from indicating the portion of the Service Indicator Virtual Bitmap and the Partial Virtual Bitmap subfield that corresponds to a group-addressed frame. Alternatively, the AID offset subfield may indicate the portion of the Service Indicator Virtual Bitmap and the Partial Virtual Bitmap subfield that does not correspond to a group-addressed frame.

[0276] The portion of the service indication virtual bitmap and the portion of the virtual bitmap subfield corresponding to the group addressing frame may include the portion corresponding to the reporting AP (or, if the reporting AP belongs to the multi-BSSID set, the transmission BSSID), the portion corresponding to the non-transmission BSSID (if the reporting AP belongs to the multi-BSSID set), the portion corresponding to other APs in the same AP multilink device as the reporting AP, and the portion corresponding to other APs in the AP multilink device to which the non-transmission BSSID (if the reporting AP belongs to the multi-BSSID set) belongs.

[0277] In other words, the value of the AID offset subfield may not be allowed to be equal to or less than the smaller of (X-1) plus N*((the number of non-transmitted BSSIDs or the maximum number of non-transmitted BSSIDs) + 1) and (X-1) plus the bitmap limit (either of these two values ​​if they are the same). The value of the AID offset subfield may be set to a value greater than the smaller of (X-1) plus N*((the number of non-transmitted BSSIDs or the maximum number of non-transmitted BSSIDs) + 1) and (X-1) plus the bitmap limit (either of these two values ​​if they are the same). As mentioned above, (X-1) may be the last bit of the group addressing frame used to indicate the APs attached to the AP multilink device to which the AP corresponding to the reporting AP or the transmitted BSSID is attached. That is, the AID offset subfield may not be allowed to indicate a value equal to or less than min((X-1) + N*X, X-1 + bitmap limit). The value of the AID offset subfield can be set to a value greater than min((X-1)+N*X, X-1+bitmap limit). In this case, the previously described terms for N and the bitmap limit are omitted.

[0278] As another way of describing the same content, (the maximum number of BSSIDs that a multi-BSSID set can include) or (the number of BSSIDs in a multi-BSSID set) can be referred to as M. The value of the AID offset subfield cannot be set to be equal to or less than the smaller of 1) the sum of M-1 and M*N, and 2) the sum of M-1 and N + bitmap limit. The value of the AID offset subfield can be set to be greater than the smaller of 1) the sum of M-1 and M*N, and 2) the sum of M-1 and N + bitmap limit. If the reported AP does not belong to a multi-BSSID set, then M can be 1.

[0279] Furthermore, the same content can be explained separately for the case where the reported AP belongs to a multiple BSSID set and the case where it does not belong to a multiple BSSID set. If the reported AP belongs to a multiple BSSID set, the value of the AID offset subfield cannot be set to be equal to or less than N. However, the value of the AID offset subfield can be set to a value greater than N. If the reported AP belongs to a multiple BSSID set, the AID offset is not allowed to be set to the smaller of the sum of (X-1) and N*(the number of non-transmitting BSSIDs or the maximum number of non-transmitting BSSIDs) and (X-1) and the bitmap limit (if the two values ​​are the same, either value will be used). The value of the AID offset subfield can be set to a value greater than the smaller of the sum of (X-1) and N*(the number of non-transmitting BSSIDs or the maximum number of non-transmitting BSSIDs) and (X-1) and the bitmap limit (if the two values ​​are the same, either value will be used). For min(A, B), if the values ​​of A and B are different, it can be the smaller of A and B, while if the values ​​of A and B are the same, it can be A = B.

[0280] In the foregoing embodiments, the number of non-transmitted BSSIDs or the number of BSSIDs in a multiple BSSID set can be the number of BSSIDs actually used in the multiple BSSID set. Furthermore, the maximum number of non-transmitted BSSIDs or the maximum number of BSSIDs that a multiple BSSID set can include can be the maximum number that can be included in the multiple BSSID set based on the MaxBSSID indicator value.

[0281] exist Figures 19 to 20 In this embodiment, the AID (Associated ID) space (for non-AP stations or non-AP MLDs) may be limited. This is because in Figure 19 and Figure 20 In this embodiment, the AID range assigned to the group addressing frame has changed. The AID is assigned by the AP to non-AP stations (or non-AP multi-link devices). Furthermore, the AID can be sent to non-AP stations (or non-AP multi-link devices) in an association response frame or a reassociation response frame.

[0282] In the existing IEEE 802.11 standard, an Access Point (AP) can assign a value of 1 (2007) as an AID to a non-AP station. However, if the AP belongs to a multiple BSSID set, it cannot assign an AID value corresponding to a non-transmitting BSSID as an AID to a non-AP station. In other words, if the AP belongs to a multiple BSSID set, it cannot assign a value equal to or less than the maximum number of BSSIDs in the multiple BSSID set minus 1 as an AID for a non-AP station. That is, the AP can assign values ​​up to 2007 (the maximum number of BSSIDs in the multiple BSSID set) as AIDs for non-AP stations.

[0283] Furthermore, the EHT standard may not allow an AP to assign 2007 as an AID for a non-AP station. This is because the AID value 2007 is used to indicate a special user information field included in the trigger frame. That is, if the AP is not included in a multiple BSSID set, the AP can assign an AID in the range of 1 to 2006 to a non-AP station. However, when using a multiple BSSID set, the AP can assign AIDs in the range up to 2006 to a non-AP station (the maximum number of BSSIDs in the multiple BSSID set).

[0284] Furthermore, according to embodiments of the present invention, the AID space can be limited based on the value of the group addressing BU indicator index field or the bitmap limit.

[0285] In a specific implementation, if the AP does not belong to the multiple BSSID set, the AP can assign an AID in the range N+1 to 2006 to non-AP stations. If the AP belongs to the multiple BSSID set, the AP may not be able to assign an AID to a non-AP station up to the smaller of the sum of (X-1) and N*((the number of non-transmitting BSSIDs or the maximum number of non-transmitting BSSIDs) + 1) and (X-1) plus the bitmap limit (if the two values ​​are the same, either value will be used) as an AID. That is, the AP can assign an AID to a non-AP station up to the smaller of the sum of (X-1) and N*((the number of non-transmitting BSSIDs or the maximum number of non-transmitting BSSIDs) + 1) and (X-1) plus the bitmap limit (if the two values ​​are the same, either value will be used) up to 2006. Therefore, if an AP belongs to a multi-BSSID set, the AP can assign a value in the range of 2^(MaxBSSID indicator) + (2^(MaxBSSID indicator)) * (2^(Group Addressing BU indicator index subfield value + 1) - 1) to 2006 as an AID for non-AP stations.

[0286] If the AP does not belong to a multi-BSSID set, the AID space can be determined based on the value of the Group Addressing BU Indicator Index subfield. Alternatively, if the AP belongs to a multi-BSSID set, the AID space can be determined based on the values ​​of the MaxBSSID Indicator subfield and the Group Addressing BU Indicator Index subfield.

[0287] The MaxBSSID indicator subfield can be included in the Multiple BSSID element and the Reduced Neighbor Report element. The Multiple BSSID element or the Reduced Neighbor Report element can be included in beacon frames, probe response frames, association response frames, and reassociation response frames.

[0288] Figure 21 The illustration shows a virtual bitmap of service instructions according to an embodiment of the present invention.

[0289] In another embodiment of the invention, Figure 19 and Figure 20 In the embodiments described, (X-1) can be replaced with (Y-1). Specifically, when (X-1) is added to the bitmap limit, (X-1) can be replaced with (Y-1). The bitmap limit can be a number from the end of the bits corresponding to other APs in the AP multilink device attached to the AP corresponding to the transmission BSSID in the service indication virtual bitmap, indicating the last bit of the group addressing frame. Furthermore, in the embodiments described later, (Y-1) can be replaced with (X-1).

[0290] As described above, an AP can generate a partial virtual bitmap subfield by extracting a portion of the service indication virtual bitmap. Furthermore, each bit of the service indication virtual bitmap or partial virtual bitmap subfield can indicate whether the service of the station for the respective bit's AID is cached. The bit number of the bits in the service indication virtual bitmap or partial virtual bitmap subfield can be mapped to an AID. The first bit B0 of the service indication virtual bitmap or partial virtual bitmap subfield can be mapped to a transmission BSSID. In another specific embodiment, the first bit B0 of the service indication virtual bitmap or partial virtual bitmap subfield can be mapped to a reporting AP. If the reporting AP belongs to a multi-BSSID set, the first bit B0 of the service indication virtual bitmap is mapped to either the reporting AP or the transmission BSSID. If the reporting AP does not belong to a multi-BSSID set, the first bit B0 of the service indication virtual bitmap is mapped to the reporting AP.

[0291] exist Figure 21In this embodiment, bits B1 to B3 of the service indication virtual bitmap can be mapped to a non-transmitting BSSID. In this case, the value of (X-1) is 3. Furthermore, bits B4 to B6 of the service indication virtual bitmap can be mapped to other APs attached to the reporting AP or the AP multilink device to which the transmitting BSSID belongs. In this case, the value of the group addressing BU indication index subfield can be set to 1. In this case, N is 3.

[0292] exist Figure 21 In this embodiment, Y is 7. Furthermore, N is 3. Therefore, bit numbers 7+(k-1)*3 to 7+k*3-1 of the service indication virtual bitmap indicate whether group addressing frames corresponding to other APs in the AP multilink device to which the AP corresponding to the k-th non-transmitting BSSID is attached are cached. That is, bits B7 to B9 of the service indication virtual bitmap can indicate whether group addressing frames corresponding to other APs in the AP multilink device to which the AP corresponding to the first non-transmitting BSSID is attached are cached. Furthermore, the k-th non-transmitting BSSID can be the non-transmitting BSSID corresponding to AID k.

[0293] The service indication virtual bitmap or partial virtual bitmap subfields may include a portion corresponding to the reporting AP (or, if using a multiple BSSID set, the transmission BSSID), a portion corresponding to (if using a multiple BSSID set) the non-transmission BSSID, a portion corresponding to other APs attached to the AP multilink device attached to the reporting AP, and a portion corresponding to (if using a multiple BSSID set) the other APs attached to the AP multilink device attached to the non-transmission BSSID, as a portion corresponding to the group addressing frame. Furthermore, the order in which the various portions are included in the service indication virtual bitmap may be the same as the order mentioned above.

[0294] In a specific embodiment, the AID space can be the same as the range of AIDs that the AID offset subfield can indicate. Furthermore, the range of AIDs that an AP cannot be assigned as an AID can be the same as the range of AIDs that the AID offset subfield cannot indicate. Additionally, the AID space can be a set of bit numbers in the service indication virtual bitmap that do not indicate whether a group addressing frame is cached. That is, the AID space may not include bit numbers in the service indication virtual bitmap that indicate whether a group addressing frame is cached. The AIDs that an AP cannot be assigned as AIDs can be a set of bit numbers in the service indication virtual bitmap that indicate whether a group addressing frame is cached.

[0295] In a first embodiment of the invention regarding the AID space, the AID space can be determined based on X or X-1. The AID space can be determined based on the maximum number of non-transmitting BSSIDs. Therefore, the AID space can be determined based on the Group Addressing BU Indicator Index subfield. Specifically, the AID space can be determined based on the sum of (X-1) and N*((the number of non-transmitting BSSIDs or the maximum number of non-transmitting BSSIDs) + 1). For example, the minimum value of the AID space can be the value of (X-1) + N*((the number of non-transmitting BSSIDs or the maximum number of non-transmitting BSSIDs) + 1). Furthermore, the maximum value of the AID space can be 2006. (X-1) can be the bit number used to indicate the last bit of a non-transmitting BSSID in a TIM element, a partial virtual bitmap subfield, or a service indication virtual bitmap. If the reporting AP does not belong to the multi-BSSID set, then X-1 is 0. If the reporting AP belongs to the multi-BSSID set, then (X-1) is (2^(the value of the MaxBSSID indicator) - 1). The MaxBSSID indicator value indicates the maximum number of BSSIDs in a multi-BSSID set. The maximum number of BSSIDs in a multi-BSSID set is 2^(MaxBSSID indicator value).

[0296] In another specific embodiment, the minimum value of the AID space can be the sum of (X-1) and N*X+1. If the reporting AP does not belong to the multiple BSSID set, the minimum value of the AID space can be N+1. If the reporting AP belongs to the multiple BSSID set, the minimum value of the AID space can be the sum of (X-1) and N*((the number of non-transmitting BSSIDs or the maximum number of non-transmitting BSSIDs)+1)+1. That is, if the AP belongs to the multiple BSSID set, the minimum value of the AID space can be (2^(MaxBSSID indicator value)-1)+(2^(MaxBSSID indicator value))*(2^(Group Addressing BU indicator index subfield value +1)-1)+1. If the AP belongs to the multiple BSSID set, the minimum value of the AID space can be 2^((MaxBSSID indicator value)+(Group Addressing BU indicator index subfield value +1)).

[0297] In a second embodiment of the invention regarding the AID space, the AID space can be determined based on a bitmap limit. In this case, the bitmap limit may be 48 bits. The AID space can be determined based on Y and the bitmap limit. Specifically, the AID space can be determined based on Y-1 and the bitmap limit. More specifically, the AID space can be determined based on the sum of Y-1 and the bitmap limit. In a specific embodiment, the minimum value of the AID space can be (Y-1) + bitmap limit + 1.

[0298] As mentioned above, Y can be replaced by X. Therefore, the AID space can be determined based on X and the bitmap limit. Specifically, the AID space can be determined based on X-1 and the bitmap limit. More specifically, the AID space can be determined based on the sum of X-1 and the bitmap limit. In a specific embodiment, the minimum value of the AID space can be (X-1) + bitmap limit + 1.

[0299] (Y-1) can be the last bit of the group addressing frame of the AP multilink device to which the AP corresponding to the transport BSSID is attached in the service indication virtual bitmap. That is, Y-1 can be the same value as X+N-1. Furthermore, N is the N described in the aforementioned embodiments regarding EHT operating elements. N can be determined based on the value of the group addressing BU indication index subfield. N can be 2^(the value of the group addressing BU indication index subfield + 1) - 1. N can be the value of the number of bits in the service indication virtual bitmap indicating the group addressing frame for a multilink device minus 1. Alternatively, N can be the number of bits in the group addressing frame corresponding to the reporting AP, other APs of the multilink device to which the reporting AP is attached, or the AP corresponding to the transport BSSID or non-transport BSSID. If the reporting AP does not belong to the multiple BSSID set, then Y-1 can be N. If the reporting AP belongs to the multiple BSSID set, then Y-1 can be X-1+N. That is, if the reporting AP belongs to the multiple BSSID set, then Y-1 can be ((the maximum number of BSSIDs in the multiple BSSID set) - 1) + N.

[0300] An AP may not be permitted to assign an AID corresponding to up to a bit limit after the bit number (Y-1) in the service indication virtual bitmap to a non-AP site or a non-AP multi-link device. In other words, an AP can assign a value greater than (Y-1) + (bitmap limit) to a non-AP site or a non-AP multi-link device. Figure 20 In this embodiment, the AP can assign a value greater than 6+48 and greater than or equal to 55 to the AID of a non-AP station or a non-AP multi-link device.

[0301] If the bit limit is 48, then when the reporting AP does not belong to a multi-BSSID set, the AID value that the reporting AP can be assigned can be (N+1) or greater. Furthermore, if the AP belongs to a multi-BSSID set, then the AID value that the AP can be assigned can be (Y+48) or greater.

[0302] In the third embodiment of the present invention regarding the AID space, the AID space can be determined based on the first and second embodiments. The AID space can be determined based on X, N, Y, the number of non-transmitting BSSIDs (or the maximum number of non-transmitting BSSIDs), and the bitmap limit. The minimum value of the AID space can be the smaller of the sum of (X-1) and N*((the number of non-transmitting BSSIDs or the maximum number of non-transmitting BSSIDs) + 1) and the sum of (Y-1) and the bitmap limit, plus 1. The minimum value of the AID space can be min((X-1) + N*X, Y-1 + bitmap limit) + 1. That is, the minimum value of the AID space can be min(X + N*X, Y + bitmap limit).

[0303] If the reporting AP does not belong to the multi-BSSID set, the minimum value of the AID space can be N+1. If the reporting AP belongs to the multi-BSSID set, the minimum value of the AID space can be the smaller of N+1 and Y+bitmap limit. If the reporting AP belongs to the multi-BSSID set, the minimum value of the AID space can be the smaller of (X-1) plus N*((the number of non-transmitting BSSIDs or the maximum number of non-transmitting BSSIDs)+1) and (Y-1) plus the bitmap limit, plus 1. That is, if the reporting AP belongs to the multi-BSSID set, the minimum value of the AID space can be min(X+N*X, Y+bitmap limit). This can be expressed as follows. If the reporting AP belongs to the multi-BSSID set, the minimum value of the AID space can be min((a), (b)).

[0304] (a)(2^(MaxBSSID indicator value)-1)+(2^(MaxBSSID indicator value))*(2^(Group Addressing BU indicator index subfield value+1)-1)+1

[0305] (b) (Y-1) + (Bitmap Limit) + 1 = 2^(MaxBSSID Indicator Value) - 1 + 2^(Group Addressing BU Indicator Index Subfield Value + 1) - 1 + (Bitmap Limit) + 1 = 2^(MaxBSSID Indicator Value) + 2^(Group Addressing BU Indicator Index Subfield Value + 1) - 1 + (Bitmap Limit)

[0306] If the bitmap limit is 48 and the reported AP does not belong to the multi-BSSID set, then the minimum value of the AID space is N+1. If the bitmap limit is 48 and the reported AP belongs to the multi-BSSID set, then the minimum value of the AID space can be min(Y+48, Y+N*(number of non-transmitting BSSIDs or maximum number of non-transmitting BSSIDs)).

[0307] In the formulas applied when reporting an AP that does not belong to a multi-BSSID set and when reporting an AP that does belong to a multi-BSSID set, the value of the MaxBSSID indicator can be 0, and the number of non-transmitting BSSIDs or the maximum number of non-transmitting BSSIDs can also be 0. In the foregoing embodiments, the number of non-transmitting BSSIDs or the number of BSSIDs in the multi-BSSID set can represent the number of BSSIDs actually used in the multi-BSSID set. Furthermore, the maximum number of non-transmitting BSSIDs or the maximum number of BSSIDs that the multi-BSSID set can have can be determined based on the MaxBSSID indicator value. A non-AP station can obtain the number of non-transmitting BSSIDs from a multi-BSSID element. In another specific embodiment, a non-AP station can obtain the number of non-transmitting BSSIDs from an element or frame indicating the maximum number of BSSIDs in the multi-BSSID set.

[0308] Furthermore, bitmap limits can be predetermined values. For example, a bitmap limit can be 48.

[0309] In the foregoing embodiments, multiple BSSIDs or sets of multiple BSSIDs can be replaced by co-located BSSIDs or sets of co-located BSSIDs (a list of co-located BSSIDs). Furthermore, a co-located BSSID can be the BSSID of a reporting BSS or a BSS having the same physical location as a reporting AP. A co-located BSSID can also be a BSSID corresponding to the same physical device as the reporting BSS or reporting AP.

[0310] In the first embodiment of the invention regarding the AID space, when the number of BSSIDs in the multiple BSSID set is small or N is small, there is an advantage of fewer bits in the indicator group addressing frame in the service indication virtual bitmap and a wider AID space. However, if the number of BSSIDs in the multiple BSSID set is large or N is large, there is a disadvantage of increased bits in the indicator group addressing frame in the service indication virtual bitmap and a narrower AID space. A wide or narrow AID space may mean a large or small number of stations or multi-link devices that can be associated. Furthermore, compared to the third embodiment of the invention regarding the AID space, the first embodiment of the invention regarding the AID space has the advantage of simpler calculation and implementation.

[0311] In the second embodiment of the invention regarding the AID space, there is an advantage that even when the number of BSSIDs in the multiple BSSID set is large or N is large, the number of bits used to indicate group-addressed frames in the service indication virtual bitmap is limited, and the AID space is wide. However, when the number of BSSIDs in the multiple BSSID set is small or N is small, there is also a disadvantage that the AID space may be limited to some extent. Therefore, there may be AID values ​​that are not used as AIDs and also not used to indicate group-addressed frames. Furthermore, compared to the third embodiment of the invention regarding the AID space, the second embodiment of the invention regarding the AID space can have the advantage of being simpler to calculate and implement.

[0312] The third embodiment of the present invention regarding AID space can combine the advantages of the first and second embodiments while reducing their disadvantages. However, the third embodiment of the present invention regarding AID space may be more computationally or practically complex than the first or second embodiments.

[0313] Will pass Figures 22 to 26 This describes the method used to set up multiple links. First, refer to... Figure 22 Describe multi-link elements.

[0314] Figure 22 The diagram illustrates the signaling associated with multi-link elements and MediumSyncDelay according to an embodiment of the present invention.

[0315] Multilink devices can use multilink elements to perform multilink discovery and multilink setup. In this case, the multilink element can be included in a management frame. Specifically, the multilink element can be included in at least one of a beacon frame, probe request frame, probe response frame, authentication frame, association request frame, association response frame, reassociation request frame, and reassociation response frame.

[0316] A multi-link element can include an Element ID subfield, a Length subfield, an Element ID Extension subfield, a Multi-Link Control subfield, a Common Info subfield, and a Link Info subfield. The Element ID or Element ID Extension subfield indicates the ID of the element that includes it. The Length subfield indicates the length of the element that includes it. The Multi-Link Control subfield can include a Type subfield and a Presence Bitmap subfield. The Type subfield indicates the type of the multi-link element. Furthermore, the format of the multi-link element can be determined based on its type. The Presence Bitmap subfield indicates whether to include any subfields that can be included in a multi-link element. For example, the Presence Bitmap subfield can indicate whether to include any subfields that can be included in the Common Info subfield of the multi-link element. The subfields indicated by the presence / absence bitmap subfields may include the MAC address subfield of the multi-link device, the Link ID Info subfield, the BSS Parameters Change Count subfield, the Medium Synchronization Delay Information subfield, the EML Capabilities subfield, and the MLD Capabilities subfield. Furthermore, the Medium Synchronization Delay Information subfield may include information related to MediumSyncDelay.

[0317] The Public Information subfield may include information about multiple links or all links. The Public Information subfield may include information commonly needed or applicable to multiple links or all links. The Link Information subfield may include information about the link corresponding to the Link Information subfield.

[0318] Information related to MediumSyncDelay can represent the duration to be set to MediumSyncDelay, and can have a default value. Under certain circumstances, the multilink device can initialize the duration of MediumSyncDelay to the default value. Furthermore, if the multilink device (non-AP multilink device) does not receive information related to MediumSyncDelay from the peer multilink device (AP multilink device), the multilink device can set the duration of MediumSyncDelay to the default value. When the multilink device (non-AP multilink device) receives information related to MediumSyncDelay from the peer multilink device (AP multilink device), it can set the duration of MediumSyncDelay to the value indicated by the received information related to MediumSyncDelay.

[0319] exist Figure 22 In this context, the medium synchronization delay information subfield may include the medium synchronization duration subfield, the medium synchronization OFDM ED threshold subfield, and the medium synchronization maximum number of TXOPs subfield.

[0320] The Medium Synchronization Duration subfield can indicate the MediumSyncDelay timer. In other words, it can indicate the value used to set the MediumSyncDelay timer. For example, the Medium Synchronization Duration subfield can be an 8-bit field. Furthermore, it can indicate the duration in 32µs units. That is, if the Medium Synchronization Duration subfield is set to A, the time indicated by it can be A * 32µs.

[0321] When MediumSyncDelay is applied, the Medium Synchronization OFDM ED Threshold subfield can indicate the CCA threshold. The CCA threshold indicated by the Medium Synchronization OFDM ED Threshold subfield can be the CCA ED threshold. That is, the Medium Synchronization OFDM ED Threshold subfield can indicate dot11MSDOFDMEDthreshold. The Medium Synchronization OFDM ED Threshold subfield can be a 4-bit field. The CCA threshold indicated by the Medium Synchronization OFDM ED Threshold subfield is the value of the Medium Synchronization OFDM ED Threshold subfield added to -72, and the unit of the CCA threshold can be dBm. Therefore, when the value of the Medium Synchronization OFDM ED Threshold subfield is 0 or greater, the CCA threshold indicated by the Medium Synchronization OFDM ED Threshold subfield can be -72dBm or greater. Furthermore, the maximum value of the CCA threshold indicated by the Medium Synchronization OFDM ED Threshold subfield can be -62dBm. In this case, the value of the Medium Synchronization OFDM ED Threshold subfield can be set between 0 and 10. At this point, values ​​of 11 to 15 can be reserved for the media synchronization OFDM ED threshold subfield. That is, the media synchronization OFDM ED threshold subfield is set to 0 to 10, at which point it can indicate a CCA threshold of -72dBm to -62dBm. Specifically, if the value of the media synchronization OFDM ED threshold subfield is x, then it can indicate a CCA threshold of (x - 72dBm).

[0322] The Medium Synchronization Maximum TXOP subfield can indicate MSD_TXOP_MAX. That is, the Medium Synchronization Maximum TXOP subfield can indicate the maximum number of transmission attempts a station can attempt during the application of MediumSyncDelay. The Medium Synchronization Maximum TXOP subfield can be a 4-bit field. In a specific embodiment, the value of the Medium Synchronization Maximum TXOP subfield can be MSD_TXOP_MAX. In another specific embodiment, the value of the Medium Synchronization Maximum TXOP subfield can be (MSD_TXOP_MAX + 1). In yet another specific embodiment, the value of the Medium Synchronization Maximum TXOP subfield can be (MSD_TXOP_MAX - 1). This embodiment can be applied when the value of the Medium Synchronization Maximum TXOP subfield is not set to the maximum value. If the value of the Medium Synchronization Maximum TXOP subfield is set to the maximum value, for example, if the Medium Synchronization Maximum TXOP subfield is a 4-bit field and is set to 15, then the Medium Synchronization Maximum TXOP subfield can indicate that there is no limit to the number of transmission attempts allowed by the station during the application of MediumSyncDelay.

[0323] Figure 23 The diagram illustrates a multi-link setup process according to an embodiment of the present invention.

[0324] Figure 23 In this configuration, the AP multi-link device includes a first AP (AP1), a second AP (AP2), and a third AP (AP3). The non-AP multi-link device (non-AP MLD) includes a first non-AP station (STA1), a second non-AP station (STA2), and a third non-AP station (STA3). The first AP (AP1) and the first non-AP station (STA1) operate on the first link (Link1). Furthermore, the second AP (AP2) and the second non-AP station (STA2) operate on the second link (Link2). Additionally, the third AP (AP3) operates on the third link (Link3).

[0325] The first AP (AP1) can signal the presence of the AP Multilink Device (AP MLD) and related parameters by sending a Reduced Neighbor Report element. The Reduced Neighbor Report element sent by the first AP (AP1) can include information about the second AP (AP2) or the third AP (AP3). The Reduced Neighbor Report element can be included in a beacon frame or a probe response frame.

[0326] Furthermore, upon receiving a frame including a reduced neighbor report element, the first non-AP station STA1 can identify the AP or AP multilink device indicated by the reduced neighbor report element. At this time, the first non-AP station STA1 sends a probe request frame including multilink elements to the first AP AP1, requesting information about the multilinks operated by the AP multilink device AP MLD or AP MLD. The multilink elements may include information about non-AP multilink devices or information about APs included in the non-AP multilink devices.

[0327] The first AP (AP1) can respond to a probe request frame by sending a probe response frame to a non-AP station (STA1). In this case, the probe response frame may include multi-link elements. These multi-link elements may include information about the AP multi-link device or information about the APs included in the AP MLD (AP Multi-Link Device). Specifically, the multi-link elements may include the information requested by the first non-AP station (STA1).

[0328] The first non-AP station STA1 can send an association request frame or a reassociation request frame to the first AP AP1. Both the association request frame and the reassociation request frame can include multi-link elements. In this case, the multi-link elements can include information about the links on which the non-AP multi-link device wants to perform multi-link settings. For example, in... Figure 22 In this context, the multi-link element can include information about the first link Link1 and the second link Link2.

[0329] The first AP (AP1) can send an association response frame or a reassociation response frame to the first non-AP (STA1) station. In this case, the association response frame and the reassociation response frame can include multi-link elements. These multi-link elements can include information about the link on which multi-link configuration is performed. The link on which multi-link configuration is performed can be determined based on the link on which the non-AP multi-link device wants to perform multi-link configuration. Figure 22 In this context, the multilink element can include information about the first link Link1 and the second link Link2 that the first non-AP station STA1 wants to perform multilink settings on.

[0330] If the associated response frame or reassociated response frame is successfully sent, it can be considered that the multilink setup for the link indicated by the multilink element included in the associated response frame or reassociated response frame has been successfully performed.

[0331] Figure 24 The illustration shows the format of a Reduced Neighbor Report element according to an embodiment of the present invention.

[0332] Further description Figure 23 The Reduced Neighbor Report element described in [the document].

[0333] The station or AP that sends the element is called the reporting station and reporting AP. Furthermore, the station or AP indicated by the element is called the reported station or reported AP. The station or AP that sends the reduced neighbor report element or multi-link element is called the reporting station or reporting AP. The station or AP indicated by the reduced neighbor report element or multi-link element is called the reported station or reported AP.

[0334] Reference Figure 24 (a) A reduced neighbor report element may include an Element ID subfield, a Length subfield, and one or more Neighbor AP Information subfields. The Element ID subfield indicates the ID of the element. The Length subfield indicates the size of the reduced neighbor report element. For example, the Length subfield can indicate the length of the reduced neighbor report element in addition to the Element ID and Length subfields. That is, in Figure 24 In embodiment (a), the length subfield may indicate the length of the neighbor AP information subfield.

[0335] Each of the one or more neighbor AP information fields included in the reduced neighbor report element can be compared with... Figure 24The neighbor AP information subfields shown in (b) are the same. The neighbor AP information subfields may include the TBTT Information Header subfield, the Operating Class subfield, the Channel Number subfield, and the TBTT Information Set subfield.

[0336] The TBTT message header subfields can be two octet fields. Furthermore, the format of the TBTT message header subfields can be as follows: Figure 24 As shown in (c), the TBTT information header subfields may include the TBTT Information Field Type subfield, the Filtered Neighbor AP subfield, the Reserved subfield, the TBTT Information Count subfield, and the TBTT Information Length subfield. The TBTT Information Field Type subfield is a 2-bit field, the Filtered Neighbor AP subfield is a 1-bit field, the Reserved subfield is a 1-bit field, the TBTT Information Count subfield is a 4-bit field, and the TBTT Information Length subfield is an 8-bit field.

[0337] The TBTT Information Field Type subfield, together with the TBTT Information Length subfield, identifies the TBTT Information subfield. The value of the TBTT Information Field Type subfield can be set to 0, and the values ​​1, 2, and 3 in the TBTT Information Field Type subfield can be reserved values.

[0338] If the probe response frame sent by the TVHT AP does not include the Filter Neighbor AP subfield, the Filter Neighbor AP subfield is set to a reserved field. It is reserved unless the Reduced Neighbor Report element is carried in the probe response frame sent by the TVHT AP. If the probe response frame sent by the TVHT AP includes the Filter Neighbor AP subfield and all BSSs of the APs in the Filter Neighbor AP subfield correspond to a specific SSID, the value of the Filter Neighbor AP subfield can be set to 1. Otherwise, the value of the Filter Neighbor AP subfield can be set to 0.

[0339] The TBTT Information Count subfield can indicate the number of TBTT Information Subfields included in the neighboring AP Information Subfield that includes the TBTT Information Count subfield. For example, the TBTT Information Count subfield can be set to a value obtained by subtracting 1 from the number of TBTT Information Subfields included in the neighboring AP Information Subfield that includes the TBTT Information Count subfield.

[0340] The TBTT Information Length subfield can indicate the length of each TBTT Information subfield included in the neighbor AP Information subfield that includes the TBTT Information Length subfield. Furthermore, the TBTT Information Length subfield can indicate the configuration of each TBTT Information subfield included in the neighbor AP Information subfield that includes the TBTT Information Length subfield. In this case, the TBTT Information Length subfield can indicate both the length and configuration of each TBTT Information subfield.

[0341] The TBTT information set subfields can include one or more TBTT information subfields.

[0342] TBTT information subfields can be like Figure 24 As shown in (d), the TBTT information subfields may include the Neighbor AP TBTT Offset subfield, the BSSID subfield, the Short SSID subfield, the BSS Parameters subfield, the 20MHz PSD subfield, and the MLD Parameters subfield. The size of each subfield can be as follows: Figure 24 As shown in (d). At this point, the TBTT information subfield can be optionally included.

[0343] The Neighbor AP TBTT Offset subfield indicates the offset value obtained by rounding down the interval between the previous TBTT and the next TBTT of the AP sending the Reduced Neighbor Report element to the nearest TU. A value of 254 indicates an offset value of 254TU or greater. A value of 255 indicates an unknown offset value.

[0344] The BSSID subfield can indicate the BSSID.

[0345] The Short SSID subfield can indicate the SSID. Specifically, the Short SSID subfield can indicate a shortened SSID.

[0346] The BSS parameter subfields can indicate information about the BSS. This information can include details about BSS operation.

[0347] The 20MHz PSD subfield indicates the maximum transmission power for the default category in the 20MHz main channel. In this case, the 20MHz PSD subfield indicates the maximum transmission power in dBm / MHz. The value of the 20MHz PSD subfield is a signed integer, and the value -128 is reserved. A value of 127 in the 20MHz PSD subfield indicates that there is no limit to the maximum transmission power for the default category. Furthermore, when the value Y of the 20MHz PSD subfield is between -127 and 126, the 20MHz PSD subfield indicates that the maximum transmission power for the default category in the MHz main channel is Y / 2dBm / MHz.

[0348] The TBTT information field configuration, indicated by the value of the TBTT information length subfield, can be as follows: If the value of the TBTT information length subfield is 1, the TBTT information subfield may include the neighbor AP TBTT offset subfield. If the value of the TBTT information length subfield is 2, the TBTT information subfield may include the neighbor AP TBTT offset subfield and the BSS parameter subfield. If the value of the TBTT information length subfield is 4, the TBTT information subfield may include the neighbor AP TBTT offset subfield and the MLD parameter subfield. If the value of the TBTT information length subfield is 5, the TBTT information subfield may include the neighbor AP TBTT offset subfield and the short SSID subfield. If the value of the TBTT information length subfield is 6, the TBTT information subfield may include the neighbor AP TBTT offset subfield, the short SSID subfield, and the BSS parameter subfield. If the value of the TBTT information length subfield is 7, the TBTT information subfield may include the neighbor AP TBTT offset subfield and the BSSID subfield. If the TBTT information length subfield value is 8, then the TBTT information subfield can include the neighbor AP TBTT offset subfield, BSSID subfield, and BSS parameter subfield. If the TBTT information length subfield value is 9, then the TBTT information subfield can include the neighbor AP TBTT offset subfield, BSSID subfield, BSS parameter subfield, and 20MHz PSD subfield. If the TBTT information length subfield value is 10, then the TBTT information subfield can include the neighbor AP TBTT offset subfield, BSSID subfield, and MLD parameter subfield. If the TBTT information length subfield value is 11, then the TBTT information subfield can include the neighbor AP TBTT offset subfield, BSSID subfield, and short SSID subfield. If the TBTT information length subfield value is 12, then it can include the TBTT information subfield, the neighbor AP TBTT offset subfield, BSSID subfield, short SSID subfield, and BSS parameter subfield. If the value of the TBTT information length subfield is 13, then the TBTT information subfields may include the neighbor AP TBTT offset subfield, BSSID subfield, short SSID subfield, BSS parameter subfield, and 20MHz PSD subfield. If the value of the TBTT information length subfield is 16, then the TBTT information subfields may include the neighbor AP TBTT offset subfield, BSSID subfield, short SSID subfield, BSS parameter subfield, 20MHz PSD subfield, and MLD parameter subfield.If the value of the TBTT information length subfield is 17 or greater, the TBTT information subfield may include the neighbor AP TBTT offset subfield, BSSID subfield, short SSID subfield, BSS parameter subfield, 20MHz PSD subfield, and MLD parameter subfield in the first 16 octets. The remaining subfields of the TBTT information subfield not previously described may be designated as reserved. That is, when the TBTT information length subfield is 4, 10, 16, or 17 or more, the MLD parameter subfield may be included.

[0349] MLD parameter subfields can be like... Figure 24 As shown in (e), the MLD parameter subfields may include an MLD ID subfield, a Link ID subfield, a BSS parameter change count subfield, and a reserved subfield. The MLD ID subfield may be an 8-bit field. Additionally, the Link ID subfield may be a 4-bit field. Furthermore, the BSS parameter change count subfield may be an 8-bit field. Additionally, the reserved subfield may be a 4-bit field.

[0350] The MLD ID subfield can indicate the ID of a multi-link device, such as the ID of an AP multi-link device. The MLD subfield can also indicate the ID of a multi-link device corresponding to a TBTT information subfield that includes the MLD ID subfield. Specific methods for setting the MLD ID subfield can be found as follows... Figure 25 As shown.

[0351] The Link ID subfield indicates the ID of the link corresponding to the reported AP. If the reported AP is not attached to a multi-link device or the reporting AP does not have relevant information, the Link ID can be set to 15.

[0352] The BSS parameter change count subfield indicates the value that increments when a critical update occurs in the beacon frame of the reported AP. The value of the BSS parameter change count subfield can be initialized to 0. The value of the BSS parameter change count subfield can be incremented by 1 each time a critical update occurs in the AP or BSS corresponding to the BSS parameter change count subfield. Critical updates can include updates to pre-specified parameters. Pre-specified parameters can include operation parameters. If the reported AP is not attached to a multilink device or the reporting AP does not have information about the multilink device to which the reported AP is attached, the value of the BSS parameter change count subfield can be set to 255.

[0353] Figure 25 The figure illustrates a method for setting the ID of a multi-link device according to an embodiment of the present invention.

[0354] The ID of a multi-link device can be determined by... Figure 24The value indicated by the MLD ID subfield described herein. Furthermore, the MLD ID subfield can be 8 bits. The MLD ID subfield can represent a value from 0 to 255. In embodiments of the invention, the reporting AP can represent the AP that sets and sends the MLD ID subfield. Furthermore, the reported AP can indicate the AP indicated by the MLD ID subfield or a TBTT information subfield including the MLD ID subfield.

[0355] According to an embodiment of the present invention, the MLD ID subfield can be set as follows: The MLD ID subfield can indicate the ID of the AP multilink device to which the reported AP is attached. If the reported AP is attached to the AP multilink device to which the reporting AP is attached, the MLD ID subfield can be set to 0. If the reported AP belongs to the multilink device set to which a non-transport BSSID belongs in the multi-BSSID set, the value of the MLD ID subfield can be set to the same value as the value of the BSSID index field of the multi-BSSID index element in the non-transport BSSID profile corresponding to the non-transport BSSID. If the reported AP is part of another AP multilink device, and the frame including the MLD ID subfield does not include a multi-BSSID element, the value of the MLD ID subfield can be set to a value greater than 0 and less than 255. Furthermore, if the reported AP is part of another AP multilink device, and the frame including the MLD ID subfield includes a multi-BSSID element, the value of the MLD ID subfield can be set to a value greater than 2^n-1 and less than 255. In this case, n is the value of the MaxBSSID indicator subfield of the multi-BSSID element. If the reported AP is not part of a multilink device or the reporting AP does not have information about the multilink device, the value of the MLD ID subfield can be set to 255. That is, if the reported AP is attached to the multilink device to which the reporting AP is attached, the value of the MLD ID subfield can be set to 0. Specifically, if the reported AP is not part of a multilink device or the reporting AP does not have information about whether the reported AP is attached to a multilink device, the value of the MLD ID subfield can be set to 255. That is, if the reported AP is attached to the multilink device to which the reporting AP is attached, the value of the MLD ID subfield can be set to 0.

[0356] exist Figure 25In this embodiment, the reporting AP operates on the first link, Link1. The reporting AP is attached to the first multi-link device and sends a reduced neighbor report element and an MLD ID subfield. Furthermore, the first multi-link device, MLD1, operates on the first link, Link1, the second link, Link2, and the third link, Link3. In this case, the reporting AP sets the value of the MLD ID subfield corresponding to the AP operating in each of the second and third links, Link2, to 0.

[0357] Furthermore, the reporting AP can send the multiple BSSID element along with the reduced neighbor report element. In another specific embodiment, the reporting AP may not send the multiple BSSID element. In this case, the reporting AP may send the multiple BSSID element if it belongs to a set of multiple BSSIDs. Conversely, the reporting AP may not send the multiple BSSID element if it does not belong to a set of multiple BSSIDs.

[0358] According to an embodiment of the present invention, when the reported AP is included in a multi-BSSID set to which the reporting AP belongs, the value of the MLDID subfield can be set to the BSSID index of the multi-BSSID set. Furthermore, if the reported AP is attached to a multi-link device attached to an AP in the multi-BSSID set to which the reporting AP belongs, the value of the MLDID subfield can be set to the BSSID index of the AP belonging to the corresponding multi-BSSID set. If the reported AP is attached to a multi-link device attached to an AP that does not transmit a BSSID in the multi-BSSID set to which the reported AP belongs, the value of the MLDID subfield can be set to the BSSID index of the reported AP.

[0359] The set of multiple BSSIDs to which the reporting AP is attached can include APs operating on the first link (Link1) and attached to the second multi-link device (MLD2). The second multi-link device (MLD2) can include both APs operating on the first link (Link1) and APs operating on the second link (Link2). The reporting AP can set the value of the MLD ID subfield corresponding to the APs attached to the second multi-link device (MLD2) and operating on the first link (Link1) and the APs attached to the second multi-link device (MLD2) and operating on the second link (Link2) to the BSSID index of the reported AP. This is because the APs attached to the second multi-link device (MLD2) and operating on the first link (Link1) and the second multi-link device (MLD2) operating on the second link (Link2) belong to the same set of multiple BSSIDs as the reporting AP, or are multi-link devices included in the set of multiple BSSIDs to which the reporting AP belongs.

[0360] When a reporting AP sends a multiple BSSID element, if the reported AP is not attached to the multilink device to which the reporting AP is attached, the reported AP does not belong to the multiple BSSID set to which the reporting AP belongs, and the reported AP is not attached to the multilink device to which the AP in the multiple BSSID set to which the reporting AP belongs, then the value of the MLD ID subfield can be set to a value greater than (2^n-1) and less than a predetermined value.

[0361] Furthermore, when the reporting AP sends a multiple BSSID element, if the reported AP is not attached to the multilink device to which the reporting AP is attached, the reported AP does not belong to the multiple BSSID set to which the reporting AP belongs, and the reported AP is not attached to the multilink device to which the AP belongs in the multiple BSSID set to which the reporting AP belongs, then the value of the MLD ID subfield can be set to a value greater than (2^n-1) and less than a predetermined value. This can be limited to the case where the reported AP is attached to an MLD. The predetermined value can be the maximum value that the MLD ID subfield can represent. The default value can be 255. Additionally, n can be the MaxBSSID indicator value corresponding to the multiple BSSID set including the reporting AP.

[0362] exist Figure 25 In this context, the third multi-link device MLD3 can include an AP operating on the first link Link1 and an AP operating on the second link Link2. Furthermore, the AP attached to the third multi-link device MLD3 and operating on the first link Link1 may not belong to the multi-link BSSID set to which the reporting AP belongs. In this case, the value of the MLD ID subfield for the AP attached to the third multi-link device MLD3 and operating on the first link Link1, and the AP attached to the third multi-link device MLD3 and operating on the second link Link2, can be set to a value greater than 2^n-1 and less than 255. This is because the AP attached to the third multi-link device MLD3 and operating on the first link Link1, and the AP attached to the third multi-link device MLD3 and operating on the second link Link2, are not included in the multi-link devices to which the reporting AP belongs, and these two APs are not included in the multi-link devices to which the AP belongs in the multi-link BSSID set to which the reporting AP belongs.

[0363] If the reporting AP does not send multiple BSSID elements and the reported AP is not attached to a multilink device to which the reporting AP is attached, the value of the MLD ID subfield can be set to a value greater than 0 and less than a predetermined value. Furthermore, this may be limited to cases where the reported AP is attached to a multilink device. Additionally, the predetermined value can be the maximum value that the MLD ID subfield can represent. The predetermined value can be 255.

[0364] Furthermore, if 1) the reported AP is not attached to a multilink device, 2) the reporting AP does not have information regarding whether the reported AP is attached to a multilink device, or 3) the reporting AP does not have the aforementioned information for setting the value of the MLD ID subfield, then the reporting AP may set the value of the MLD ID subfield to a predetermined value. In another specific embodiment, if 1) the reported AP is not attached to a multilink device, 2) the reporting AP does not have information regarding whether the reported AP is attached to a multilink device, or 3) the reporting AP does not have the aforementioned information for setting the value of the MLD ID subfield, then the reporting AP may set the value of the MLD ID subfield to a predetermined value or a larger value. The predetermined value may be the maximum value that the MLD ID subfield can represent. The predetermined value may be 255.

[0365] exist Figure 25 In this scenario, the fourth AP (AP4) operates on the first link (Link1). At this time, the fourth AP (AP4) is not attached to any multi-link device. Therefore, the reporting AP can set the value of the MLD ID subfield corresponding to the fourth AP (AP4) to 255.

[0366] A station can determine which BSS a frame originated from based on the MAC address field in the MAC header of a received frame. Specifically, the station can determine whether the received frame originated from an AP associated with the station or from an AP belonging to one of the multiple BSSIDs to which the AP associated with the station belongs. In a specific embodiment, the station can determine whether the received frame originated from an AP associated with the station or from an AP belonging to one of the multiple BSSIDs to which the AP associated with the station belongs based on the TA field in the MAC header of the received frame. In this case, if the TA field of the frame received by the station indicates the MAC address of the AP associated with the station or the MAC address of an AP belonging to one of the multiple BSSIDs to which the AP associated with the station belongs, then the station can determine that the received frame originated from the AP associated with the station or from an AP belonging to one of the multiple BSSIDs to which the AP associated with the station belongs. If the TA field of a frame received by a station does not indicate the MAC address of the AP associated with the station or the MAC address of the AP in the multi-BSSID set to which the AP associated with the station belongs, the station can determine that the received frame was sent from the AP associated with the station or from the AP in the multi-BSSID set to which the AP associated with the station belongs.

[0367] A station can determine which access point (AP) a frame is sent to based on the MAC address field in the MAC header of a received frame. In a specific embodiment, the station can determine whether the received frame is sent to an AP associated with the station or an AP belonging to one of the multiple BSSIDs of the AP associated with the station based on the RA field in the MAC header of the received frame. In this case, if the RA field of the frame received by the station indicates the MAC address of the AP associated with the station or the MAC address of an AP belonging to one of the multiple BSSIDs of the AP associated with the station, the station determines that the received frame is sent to an AP associated with the station or an AP belonging to one of the multiple BSSIDs of the AP associated with the station. If the RA field of the frame received by the station does not indicate the MAC address of the AP associated with the station or the MAC address of an AP belonging to one of the multiple BSSIDs of the AP associated with the station, the station can determine that the received frame is sent to an AP associated with the station or an AP belonging to one of the multiple BSSIDs of the AP associated with the station.

[0368] A station can determine whether a frame is an Inter-BSS frame based on the MAC address field in the MAC header of a received frame. The MAC address field can include at least one of the RA field, TA field, and BSSID field. If none of the RA, TA, and BSSID fields of a frame received by the station indicate the MAC address of the AP associated with the station or the MAC address of the AP belonging to the multiple BSSID set to which the AP associated with the station belongs, then the station can determine that the received frame is an Inter-BSS frame. If at least one of the RA, TA, and BSSID fields of a frame received by the station indicates the MAC address of the AP associated with the station or the MAC address of the AP belonging to the multiple BSSID set to which the AP associated with the station belongs, then the station can determine that the received frame is an Intra-BSS frame.

[0369] In these embodiments, BSSID can be used instead of the AP's MAC address.

[0370] If the BSS color included in the preamble of a PPDU received by a station is the same as the BSS color of the BSS to which the station belongs, and the preamble of the PPDU received by the station indicates that it is used for downlink transmission, the station can determine that the received PPDU was sent by the AP associated with the station or by an AP belonging to one of the multiple BSSIDs of the AP associated with the station. If the BSS color included in the preamble of a PPDU received by the station is different from the BSS color of the BSS to which the station belongs, or if the preamble of the PPDU received by the station does not indicate that it is used for downlink transmission, the station can determine that the received PPDU was not sent by the AP associated with the station or by an AP belonging to one of the multiple BSSIDs of the AP associated with the station.

[0371] A multiple BSSID set can be a collection of multiple BSSs capable of signaling information about a BSS using a single beacon frame or a single probe response frame. Specifically, a set of BSSIDs indicated by a single multiple BSSID element can be called a multiple BSSID set. Furthermore, a TIM element included in a single beacon frame or a single TIM frame can indicate a frame buffered in the multiple BSSIDs included in the multiple BSSID set. Additionally, a single beacon frame or a single probe response frame can include multiple BSSID elements. Multiple BSSID elements can signal information about multiple BSSs. The BSSID of the BSS that sends the aforementioned single beacon frame or probe response frame is called a transport BSSID. In a multiple BSSID set, the remaining BSSIDs besides the transport BSSIDs can be called non-transport BSSIDs. Furthermore, the BSS corresponding to a non-transport BSSID may not send a beacon frame or probe response frame.

[0372] As mentioned above, the maximum number of BSSIDs that a multiple BSSID set can include can be 2^n. Here, n can be a value signaled in the multiple BSSID element. For example, n can be a value indicated by the MaxBSSID indicator included in the multiple BSSID element. A station receiving the multiple BSSID element can determine the MAC address or BSSID of the AP included in the multiple BSSID set based on the received multiple BSSID element. Furthermore, multiple BSSID indices can be mapped to individual BSSIDs included in the multiple BSSID set. Therefore, BSSIDs included in the multiple BSSID set can be identified through their BSSID indices. The maximum value of the MaxBSSID indicator can be 8.

[0373] However, there may be situations where the value of the MLDID subfield cannot be set using the aforementioned embodiments of the method for setting the MLD ID subfield.

[0374] In the foregoing embodiments, if at least one predetermined condition is met, the reporting AP can set the value of the MLD ID subfield to a predetermined value. In another specific embodiment, if a predetermined condition is met, the reporting AP can set the value of the MLD ID subfield to a predetermined value or a larger value. The predetermined value can be the maximum value that the MLD ID subfield can represent. In this case, the predetermined value can be 255. The predetermined conditions can include at least one of the following: 1) the reported AP is not attached to a multilink device, 2) the reporting AP does not have information about whether the reported AP is attached to a multilink device, and 3) the reporting AP does not have the aforementioned information used to set the value of the MLD ID subfield. Furthermore, the predetermined conditions can include: when the value of the MaxBSSID indicator field corresponding to the reporting AP is the maximum value, the reported AP is not included in the multilink device to which the AP of the multilink set to which the reporting AP belongs. This condition can be: the reporting AP sends a multilink BSSID element. The maximum value of the MaxBSSID indicator field can be 8.

[0375] When a reporting AP sends a multiple BSSID element, if the reported AP is an AP included in the multiple BSSID set that includes the reporting AP, or if the reported AP is attached to a multi-link device attached to an AP that includes the reporting AP in the multiple BSSID set, then the MLD ID subfield can be set to the BSSID index of the AP included in the multiple BSSID set. If the value of the MaxBSSID indicator subfield is 8, then the maximum number of BSSIDs that the multiple BSSID set can include can be 2^8 = 256. Therefore, based on the aforementioned conditions, there may not be a value greater than 2^n-1 and less than 255.

[0376] Furthermore, when the value of the MaxBSSID indicator subfield corresponding to the reporting AP is the maximum value, the reporting AP may be unable to set the value of the MLDID subfield even if the reporting AP is attached to a multi-link device attached to an AP belonging to a multi-BSSID set to which the reporting AP belongs. For example, the reporting AP cannot indicate a multi-link device with a BSSID index of 255. This is because, according to the aforementioned embodiment, the value of the MLD ID subfield can be set to 255. Therefore, when the value of the MLD ID subfield is 255, it is difficult to distinguish whether the 255 is set based on the BSSID index or based on a predetermined value.

[0377] Therefore, the condition for setting the value of the MLD ID subfield to a predetermined value may also include: when the value of the MaxBSSID indicator subfield corresponding to the reporting AP is the maximum value, the multi-link device to which the reported AP belongs belongs to the multi-link BSSID set to which the reporting AP belongs. In another specific embodiment, in a multi-link BSSID set, the use of 255 as the BSSID index may not be allowed.

[0378] Furthermore, according to the foregoing embodiments, regardless of whether the reporting AP sends multiple BSSID elements, the reporting AP may have difficulty setting the value of the MLD ID subfield. For example, if the reporting AP indicates information about a large number of APs, the reporting AP may have difficulty setting the value of the MLD ID subfield. Since the number of reported APs is greater than the number of configurable multilink device IDs, the reported APs may not be identifiable using multilink device IDs. For example, if the reporting AP sends multiple BSSID elements and transmits information about more than (254-2^n+1) APs, the reported APs may not be identifiable using a limited range of multilink device IDs. If the reporting AP does not send multiple BSSID elements and transmits information about more than (254-1+1) APs, the reported APs may not be identifiable using a limited range of IDs. The condition for setting the value of the MLD ID subfield to a predetermined value may also include the situation where the reported AP cannot be identified using a limited range of IDs.

[0379] To address the aforementioned issue, the size of the MLD ID subfield can be set to more than 8 bits. In this case, the predetermined value can be the maximum value that the MLD ID subfield can indicate. That is, if the MLD ID subfield size is N bits, the predetermined value can be 2^N-1. For example, the MLD ID subfield size can be 9 bits, and the predetermined value can be 511. As another example, the MLD ID subfield size can be 16 bits, and the predetermined value can be 65535.

[0380] Figures 26 to 27 The illustration shows a method for assigning AIDs to non-AP stations attached to multi-link devices according to an embodiment of the present invention.

[0381] According to an embodiment of the present invention, a multi-link device can be assigned an AID (Association ID). That is, stations included in a multi-link device can have the same AID.

[0382] AID assignment can be performed by the AP. For example, an AID assigned by the AP can be sent to a non-AP STA. A non-AP STA can recognize that the AID received from the AP is the AID corresponding to itself. A non-AP STA that receives a subfield including the AID value assigned to it can recognize that the subfield including the AID value assigned to it indicates that it is a non-AP STA.

[0383] The AID assigned to a non-AP station can be included in the association response frame or the reassociation response frame. If the AP performs multi-link configuration after assigning an AID to a non-AP station, the AID assigned to the non-AP station can be the AID assigned to the multi-link device to which the non-AP station is attached.

[0384] An AID or AID-related information can be included in the preamble of a PPDU. In this case, the PPDU preamble can use the AID to indicate that the intended receiver of the PPDU is a non-AP station corresponding to the AID. The PPDU preamble can also use the AID to indicate that the sender of the PPDU is a non-AP station corresponding to the AID. Furthermore, as mentioned above, the AID can be used to indicate traffic. A frame can use the AID to indicate that the station corresponding to that AID is the receiver of the frame. For example, a trigger frame can use the AID to indicate which station the trigger frame triggers.

[0385] An AID assigned to a multi-link device may not be allowed to be assigned to other stations or other multi-link devices. In a specific embodiment, an AID assigned to a multi-link device may not be allowed to be assigned to a station or multi-link device operating on a link not used by the multi-link device.

[0386] exist Figure 26 In this scenario, the first multi-link device MLD1 operates on the first link (Link1) and the second link (Link2). Furthermore, the second multi-link device MLD2 operates on the third link (Link3) and the fourth link (Link4). At this time, X is assigned as the AID of the first multi-link device MLD1. Therefore, the AID of the second multi-link device MLD2 is not allowed to be assigned as X; instead, it is assigned as Y.

[0387] In a specific embodiment of the present invention, an AP multi-link device can reassign the AID assigned to one multi-link device to another station or another multi-link device. If predetermined conditions are met, the AP multi-link device can reassign the AID assigned to one multi-link device to another station or another multi-link device. These predetermined conditions may include situations where multi-link devices or stations sharing the same AID operate on different links. That is, the predetermined conditions may include situations where multi-link devices sharing the same AID operate on non-overlapping links. In this case, it may be disallowed for a station or multiple multi-link devices operating on a single link to be assigned the same AID. In another specific embodiment, this may include situations where multi-link devices sharing the same AID operate on non-overlapping channels.

[0388] exist Figure 27 In (a), the first multi-link device MLD1 operates on the first link Link1 and the second link Link2. The AP multi-link device assigns X as the AID of the station of the first multi-link device MLD1. At this time, the AP multi-link device is not attached to the first multi-link device MLD1 and can assign X as the AID of the first station STA1 that operates on the third link Link3 instead of the first link Link1 and the second link Link2.

[0389] In these embodiments, if a frame includes information about multiple links, assigning a single AID to multiple multilink devices or stations could lead to confusion. To prevent this, information sent on one link can be applied to the station or multilink device operating on that link. For example, information sent on a first link can be applied to a station or multilink device operating on the first link with AID X, but not to a station or multilink device operating on a second link with AID X.

[0390] exist Figure 27 In (b), a beacon frame including a TIM is transmitted on each of the first link (Link1) and the second link (Link2). At this time, the TIMs transmitted on both the first link (Link1) and the second link (Link2) indicate that the service with AID X is cached. The TIM transmitted on the first link (Link1) indicates that the service of the multi-link device MLD1 operating on the first link (Link1) is cached, and the TIM transmitted on the second link (Link2) indicates that the service of the station STA1 operating on the second link (Link2) is cached.

[0391] Will pass Figures 28 to 30 Describe the TID to link mapping negotiation.

[0392] Figure 28This is a diagram illustrating the TID to link mapping negotiation according to an embodiment of the present invention.

[0393] As mentioned above, the default mapping can be applied to links where TID-to-link mapping has not been performed. Furthermore, if the TID-to-link mapping on a link where TID-to-link mapping negotiation has been completed is teared down, the default mapping can be reapplied to that link.

[0394] TID-to-link mapping negotiation can be performed through TID-to-link mapping requests and responses. Specifically, a multi-link device can execute a TID-to-link mapping request by sending a frame containing TID-to-link mapping elements. This frame can include an association request frame, a reassociation request frame, and a TID-to-link mapping request frame. Therefore, a non-AP station or a non-AP multi-link device can request TID-to-link mapping by sending an association request frame, a reassociation request frame, or a TID-to-link mapping request frame. An AP or an AP multi-link device can request TID-to-link mapping by sending a TID-to-link mapping request frame. A multi-link device that receives a TID-to-link mapping request can execute a TID-to-link mapping response by sending a frame containing TID-to-link mapping elements. This frame can include an association response frame, a reassociation response frame, and a TID-to-link mapping response frame. Therefore, an AP or an AP multi-link device can respond to a TID-to-link mapping request by sending an association response frame, a reassociation response frame, or a TID-to-link mapping request frame. Non-AP stations or non-AP station multi-link devices can respond to TID-to-link mapping requests by sending a TID-to-link mapping response frame.

[0395] A multi-link device can initiate TID-to-link mapping by sending a TID-to-link mapping request. In this case, the multi-link device can request a default mapping by sending a frame including TID-to-link mapping elements. A multi-link device receiving a TID-to-link mapping request can accept the TID-to-link mapping by sending a TID-to-link mapping response to the request. Alternatively, a multi-link device receiving a TID-to-link mapping request can accept the TID-to-link mapping by sending a frame that does not include TID-to-link mapping elements. In another specific embodiment, a multi-link device receiving a TID-to-link mapping request can accept the TID-to-link mapping by sending a TID-to-link mapping element that includes the same content as the TID-to-link mapping element received from a non-AP multi-link device.

[0396] Furthermore, a multi-link device receiving a TID-to-link mapping request can reject the TID-to-link mapping by sending a TID-to-link mapping response to the request. Alternatively, the multi-link device receiving the TID-to-link mapping request can reject it by sending a frame that does not include a TID-to-link mapping element. In another specific embodiment, a multi-link device receiving a TID-to-link mapping request can reject the TID-to-link mapping by sending a TID-to-link mapping element that includes content different from the content of the TID-to-link mapping element received from a non-AP multi-link device. If the TID-to-link mapping is rejected, a default mapping can be applied to the link.

[0397] In these embodiments, the frames sent by the multi-link device for TID-to-link mapping requests and responses may include at least one of an association request frame, an association response frame, a re-association request frame, a re-association response frame, a TID-to-link mapping request frame, and a TID-to-link mapping response frame. Specifically, the multi-link device receiving the TID-to-link mapping request may send a TID-to-link mapping response frame in response to the TID-to-link mapping request. At this time, the multi-link device receiving the TID-to-link mapping request can accept or reject the TID-to-link mapping request by inserting a status code into the TID-to-link mapping response frame. Specifically, the multi-link device receiving the TID-to-link mapping request can accept the TID-to-link mapping request by setting the status code of the TID-to-link mapping response frame to SUCCESS. Furthermore, the multi-link device receiving the TID-to-link mapping request can reject the TID-to-link mapping request by setting the status code of the TID-to-link mapping response frame to REJECT or DENIED_TID_TO_LINK_MAPPING. Furthermore, a multi-link device receiving a TID-to-link mapping request can reject the request by setting the status code of the TID-to-link mapping response frame to PREFERRED_TID_TO_LINK_MAPPING_SUGGESTED. In this case, the multi-link device receiving the request can suggest a preferred TID-to-link mapping while rejecting the request. Alternatively, a multi-link device receiving a TID-to-link mapping request can also reject the request by sending a TID-to-link mapping rejection frame.

[0398] The TID-to-link mapping element included in the TID-to-link mapping request indicates the TID-to-link mapping that is the object of the TID-to-link mapping request. Furthermore, the TID-to-link mapping element sent when accepting a TID-to-link mapping can indicate the accepted TID-to-link mapping. Additionally, the TID-to-link mapping element sent when rejecting a TID-to-link mapping can indicate a newly proposed TID-to-link mapping.

[0399] If a TID-to-link mapping request is accepted, the TID-to-link mapping included in the request is set on the link that is the object of the TID-to-link mapping. Alternatively, if a TID-to-link mapping request is rejected, a default mapping may be applied to the link that is the object of the TID-to-link mapping.

[0400] Furthermore, for TID-to-link mapping negotiation, both the TID-to-link mapping request frame and the TID-to-link mapping response frame may include a dialog token. The dialog token maps the TID-to-link mapping request frame to the TID-to-link mapping response frame. Specifically, if the value of the dialog token in the TID-to-link mapping request frame is the same as the value of the dialog token in the TID-to-link mapping response frame, then the TID-to-link mapping response frame is sent as a response to the TID-to-link mapping request frame. Therefore, when a multi-link device that received a TID-to-link mapping request frame sends a TID-to-link mapping response frame, the multi-link device can set the value of the dialog token in the TID-to-link mapping response frame to the value of the dialog token in the TID-to-link mapping request frame. When a multi-link device sends a TID-to-link mapping response frame without receiving a TID-to-link mapping request frame, the multi-link device sets the value of the dialog token in the TID-to-link mapping response frame to a predetermined value. In this case, the predetermined value can be 0. That is, when a multi-link device sends an unsolicited TID to link mapping response frame, the multi-link device can set the value of the session token in the TID to link mapping response frame to a predetermined value. The field indicating the session token in the TID to link mapping request frame and the TID to link mapping response frame can be a single octet. The value of the session token can be any value from 0 to 255.

[0401] If a multi-link device's capabilities support TID-to-link mapping, then the multi-link device can perform TID-to-link mapping. Furthermore, the scope of TID-to-link mapping that a multi-link device can perform can vary depending on its capabilities. For example, the number of TIDs that a multi-link device can map to links, or the number of combinations of TID and link mappings that can be applied, can vary depending on its capabilities. The capabilities of a multi-link device can indicate whether it can map all TIDs to the same link group. Additionally, the capabilities of a multi-link device can indicate how many link groups a multi-link device can map TIDs to.

[0402] exist Figure 28 In this embodiment, the AP multi-link device (AP ML) includes a first AP (AP1), a second AP (AP2), and a third AP (AP3). The non-AP multi-link device (non-AP MLD) includes a first non-AP station (non-AP STA1) and a second non-AP station (non-AP STA2). The non-AP multi-link device (non-AP MLD) sends an association request frame including a TID-to-link mapping element to the AP multi-link device (AP ML). The AP multi-link device (AP ML) sends an association response frame including a TID-to-link mapping element to the non-AP multi-link device (non-AP MLD) to accept or reject the TID-to-link mapping corresponding to the TID-to-link mapping element. Furthermore, the non-AP multi-link device (non-AP MLD) can renegotiate the TID-to-link mapping by sending a TID-to-link mapping request frame to the AP multi-link device (AP ML). In this case, the AP multi-link device (AP ML) sends a TID-to-link mapping response frame to the non-AP multi-link device (non-AP MLD) to accept or reject the TID-to-link mapping corresponding to the TID-to-link mapping element.

[0403] Figure 29 The illustration shows a TID-to-link mapping negotiation process in which an AP multi-link device sends a TID-to-link mapping request according to an embodiment of the present invention.

[0404] AP multi-link devices can send TID-to-link mapping requests through association response frames, reassociation response frames, and TID-to-link mapping request frames. Specifically, AP multi-link devices can initiate TID-to-link mapping negotiation through these frames. In this case, the AP multi-link device can include TID-to-link mapping elements within these frames. This is because TID-to-link mapping requests sent by non-AP multi-link devices may be in a form that the AP multi-link device does not expect, and non-AP multi-link devices may not send their own TID-to-link mapping requests. Furthermore, AP multi-link devices have a better understanding of the overall network situation than non-AP multi-link devices, thus enabling them to determine valid TID-to-link mappings. At this point, before completing the TID-to-link mapping negotiation, the AP multi-link device first sends an association response frame or a re-association response frame, thereby completing the multi-link setup and reset. If a non-AP multi-link device that received the TID-to-link mapping request sends a TID-to-link mapping response, the TID-to-link mapping negotiation is successfully completed.

[0405] The situations in which an AP multi-link device can send a TID-to-link mapping request via an association response frame and a reassociation response frame are limited. Specifically, if the association request frame does not request TID-to-link mapping, the AP multi-link device can send the TID-to-link mapping request via an association response frame. If the association request frame does not include a TID-to-link mapping element, the AP multi-link device can determine that the association request frame does not request TID-to-link mapping. Furthermore, if the reassociation request frame does not request TID-to-link mapping, the AP multi-link device can send the TID-to-link mapping request via a reassociation response frame. If the reassociation request frame does not include a TID-to-link mapping element, the AP multi-link device can determine that the reassociation request frame does not request TID-to-link mapping. If an association request frame sent by a non-AP multi-link device does not include a TID-to-link mapping element, the non-AP multi-link device can determine that the association response frame received as a response to the association request frame, which includes a TID-to-link mapping element, requests TID-to-link mapping. If a reassociation request frame sent by a non-AP multilink device does not include a TID-to-link mapping element, the non-AP multilink device may interpret the received reassociation response frame, which includes the TID-to-link mapping element, as a response to the reassociation request frame. This is because, in these embodiments, when both the association request frame and the reassociation response frame include a TID-to-link element, the non-AP multilink device may be confused about its intention to include the TID-to-link element in the association response frame. The same applies to the reassociation request frame.

[0406] Furthermore, in these embodiments, the AP multi-link device may not determine that the TID-to-link mapping has been successfully completed until it receives a TID-to-link mapping response from a non-AP multi-link device. Therefore, the AP multi-link device may operate according to the default mapping before receiving a TID-to-link mapping response from a non-AP multi-link device. Additionally, even if the AP multi-link device receives an ACK for an association response frame or a reassociation response frame, the AP multi-link device may not determine that the TID-to-link mapping has been successfully completed.

[0407] Non-AP multi-link devices can respond to TID-to-link mapping requests sent by AP multi-link devices via association frames or reassociation frames, according to the foregoing embodiments. However, it is necessary to explicitly indicate that the non-AP multi-link device is responding to a TID-to-link mapping request sent via an association frame or reassociation frame from the AP multi-link device. The non-AP multi-link device can send a TID-to-link mapping response as a response frame to either an association response frame or a reassociation response frame for a TID-to-link mapping request. Furthermore, the non-AP multi-link device can set the dialogue token value of the TID-to-link mapping response to the same value as the dialogue token value included in either the association response frame or the reassociation response frame for a TID-to-link mapping request. However, the association response frame and the reassociation response frame for a TID-to-link mapping request may not include a dialogue token.

[0408] Therefore, a TID-to-link mapping element may include a response indication field indicating that it is a response to a TID-to-link mapping request. In this case, the response indication field may be included within the aforementioned TID-to-link mapping control field. Specifically, the response indication field may be included within a reserved field of the reserved fields of the aforementioned TID-to-link mapping control field. For example, the response indication field may be any bit from the fourth bit B3 to the eighth bit B8 of the TID-to-link mapping control field. The multi-link device receiving the TID-to-link element can determine whether the TID-to-link mapping element requests TID-to-link mapping based on the response indication field.

[0409] Because non-AP multi-link devices send a TID to link mapping response frame in response to an association request frame or a reassociation request frame, AP multi-link devices need to distinguish which frame the TID to link mapping response frame is responding to. Specifically, when a non-AP multi-link device sends a TID to link mapping response frame in response to an association request frame or a reassociation request frame, the non-AP multi-link device can set the session token value of the TID to link mapping response frame to a random value. Furthermore, if the session token value of the TID to link mapping response frame is the same as the session token value of the TID to link mapping request frame sent by the AP multi-link device, the AP multi-link device considers the TID to link response frame to be a response to the TID to link mapping request frame. Conversely, if the session token value of the TID to link mapping response frame is different from the session token value of the TID to link mapping request frame sent by the AP multi-link device, the AP multi-link device considers the TID to link response frame to be a response to either an association request frame or a reassociation request frame.

[0410] In another specific embodiment, when the AP multi-link device sends a TID-to-link mapping request via an association response frame or a reassociation response frame, the value of the session token in the TID-to-link mapping response frame sent in response to the TID-to-link mapping request can be set to a predetermined value. This predetermined value can be 0, 1, or 255. When the AP multi-link device sends a TID-to-link mapping request via an association frame or a reassociation frame and receives a TID-to-link mapping response frame with the predetermined value as the session token, the AP multi-link device can determine that the received TID-to-link mapping response frame is a response to the sent TID-to-link mapping request.

[0411] In another specific embodiment, when the AP multi-link device sends a TID-to-link mapping request via an association response frame or a reassociation response frame, the status code of the TID-to-link mapping response frame sent in response to the TID-to-link mapping request can be a predetermined value. In this case, the predetermined value of the status code can be different from the value of the status code of the TID-to-link mapping response frame sent in response to a TID-to-link mapping request sent by the multi-link device via frames other than association and reassociation frames. Therefore, the AP multi-link device can determine whether the received TID-to-link mapping response frame is a response to a TID-to-link mapping request sent by the AP multi-link device via an association response frame or a reassociation response frame based on the status code of the received TID-to-link mapping response frame. Specifically, if the status code of the received TID-to-link mapping response frame is a predetermined value, the AP multi-link device can determine that the received TID-to-link mapping response is a response to a TID-to-link mapping request sent by the AP multi-link device via an association response frame or a reassociation response frame.

[0412] In another specific embodiment, the AP multi-link device can determine whether the received TID-to-link mapping response frame is a response to a TID-to-link mapping request sent by the AP multi-link device through an association response frame or a reassociation response frame, based on the value of the link mapping field for TID in the received TID-to-link mapping response frame. Specifically, if the value of the link mapping field for TID in the received TID-to-link mapping response frame is the same as the value of the link mapping field for TID in the TID-to-link mapping request sent by the AP multi-link device through an association response frame or a reassociation response frame, then the AP multi-link device can determine that the received TID-to-link mapping response frame is a response to a TID-to-link mapping request sent by the AP multi-link device through an association response frame or a reassociation response frame. Specifically, the received TID-to-link mapping response frame may include link mapping fields for multiple TIDs. At this point, if the values ​​of all link mapping fields included in the TID-to-link mapping response frame are the same as the values ​​of all link mapping fields in the TID-to-link mapping request sent by the AP multi-link device through an association response frame or a reassociation response frame, the AP multi-link device can determine that the received TID-to-link mapping response frame is a response to the TID-to-link mapping request sent by the AP multi-link device through an association response frame or a reassociation response frame. If the values ​​of the link mapping fields used for TID in the TID-to-link mapping response frame received by the AP multi-link device are different from the values ​​of the link mapping fields used for TID in the TID-to-link mapping request sent by the AP multi-link device through an association response frame or a reassociation response frame, the AP multi-link device may not send an ACK for the received TID-to-link mapping response frame. Furthermore, if the link mapping field for TID in the TID-to-link mapping response frame received by the AP multi-link device includes at least one value from the value of the link mapping field for TID in the TID-to-link mapping request sent by the AP multi-link device via an association response frame or a reassociation response frame, the AP multi-link device may not send an ACK for the received TID-to-link mapping response frame. Furthermore, if the TID-to-link mapping response frame received by the AP multi-link device does not include the link mapping field for TID in the TID-to-link mapping request sent by the AP multi-link device via an association response frame or a reassociation response frame, or if the value of the link mapping field in the TID-to-link mapping response frame received by the multi-link device differs from the value of the link mapping field for TID in the link mapping request sent via an association response frame or a reassociation response frame, the AP multi-link device may not send an ACK for the received TID-to-link mapping response frame. The above embodiments can still be applied even when the TID-to-link mapping request is not sent via an association response frame or a reassociation response frame.

[0413] exist Figure 29 In this embodiment, the AP multi-link device AP ML includes a first AP AP1, a second AP AP2, and a third AP AP3. The non-AP multi-link device (non-AP MLD) includes a first non-AP station (non-AP STA1) and a second non-AP station (non-AP STA2). The non-AP multi-link device (non-AP MLD) sends an association request frame to the AP multi-link device AP ML that does not include the TID-to-link mapping element. The AP multi-link device AP ML sends an association response frame to the non-AP multi-link device (non-AP MLD) that includes the TID-to-link mapping element to request the TID-to-link mapping corresponding to the TID-to-link mapping element. At this time, the non-AP multi-link device (non-AP MLD) sends a TID-to-link mapping response frame to the AP multi-link device AP ML to accept the TID-to-link mapping request.

[0414] Figure 30 The illustration shows a TID-to-link mapping negotiation process according to an embodiment of the present invention, when the link group requesting the TID-to-link mapping is different from the link group set by the TID-to-link mapping response.

[0415] The link group requesting TID-to-link mapping in an association request frame or reassociation request frame may be different from the link group for which TID-to-link mapping is expected to be set in an association response frame or reassociation response frame. For example, TID-to-link mapping may be requested for three links in an association request frame or reassociation request frame, and TID-to-link mapping may be set for two links in an association response frame or reassociation response frame. Furthermore, link groups differing from each other can include situations where link groups have different settings. Specifically, different settings for link groups can include situations where the operating channels of link groups are different. Additionally, different link groups can include situations where link groups have different configurations.

[0416] exist Figure 28 In some embodiments, when the AP multilink device receives an association request frame or reassociation request frame that includes a TID-to-link mapping element, the AP multilink device can set up the multilink by sending an association response frame or reassociation response frame that does not include a TID-to-link mapping element. However, as mentioned above, the link group requesting TID-to-link mapping in the association request frame or reassociation request frame may be different from the link group that expects to set up TID-to-link mapping in the association response frame and reassociation response frame.

[0417] Therefore, in another embodiment of the present invention, when an AP multi-link device receives an association request frame or a reassociation request frame that includes a TID-to-link mapping element, and desires to set a link group different from the link group desired by the association request frame or reassociation request frame, the AP multi-link device can send an association response frame or a reassociation response frame that does not include the TID-to-link mapping element. Thus, the AP multi-link device can reject the TID-to-link mapping. At this time, the default mapping can be applied to both the AP multi-link device and non-AP multi-link devices.

[0418] When an AP multi-link device receives an association request frame or reassociation request frame that includes a TID-to-link mapping element, and sends an association response frame or reassociation response frame that requests a link group different from the link group requested in the association request frame or reassociation request frame, the AP multi-link device may send an association response frame or reassociation response frame that does not include the TID-to-link mapping element. Furthermore, when a non-AP multi-link device sends an association request frame or reassociation request frame that includes a TID-to-link mapping element, and receives an association response frame or reassociation response frame that requests a link group different from the link group requested in the association request frame or reassociation request frame, even if the received association response frame or reassociation response frame does not include the TID-to-link mapping element, the non-AP multi-link device can determine that the TID-to-link mapping request has been rejected. In this case, the default mapping can be applied to both the AP multi-link device and the non-AP multi-link device.

[0419] In another specific embodiment, when an AP multi-link device receives an association request frame or reassociation request frame that includes a TID-to-link mapping element, and desires to set a link group different from the link group desired by the association request frame or reassociation request frame, the AP multi-link device can send an association response frame or reassociation response frame that includes a TID-to-link mapping element. In this case, the TID-to-link mapping element included in the association response frame or reassociation response frame can indicate the TID-to-link mapping suggested by the AP multi-link device. At this time, the operation of non-AP multi-link devices can be compared with the reference... Figure 28 The described embodiments are the same.

[0420] In the foregoing embodiments, the operation of the multi-link device was described for ease of explanation, but the operation of the multi-link device can also be performed by the stations included in the multi-link device.

[0421] Figure 31 The illustration shows a method for a non-AP multi-link device to determine services cached on an AP multi-link device according to an embodiment of the present invention.

[0422] Non-AP multi-link devices receive beacon frames, including beacon frames, from AP multi-link devices (S3101).

[0423] The non-AP multi-link device determines whether services for the non-AP multi-link device are cached on the multi-link device based on a partial virtual bitmap subfield of the TIM element (S3103). At this time, the partial virtual bitmap subfield includes one or more first bits and one or more second bits, and a bit set to 1 among the one or more first bits indicates that services for the non-AP multi-link device corresponding to that bit are cached on the AP multi-link device. Furthermore, a bit set to 1 among the one or more second bits indicates whether services for the non-AP station corresponding to that bit are cached on the AP multi-link device. The specific format and settings of the partial virtual bitmap subfield can be referenced in [reference needed]. Figures 13 to 18 The described embodiments.

[0424] When services intended for non-AP multi-link devices are cached on AP multi-link devices, the link on which the service is cached or which link the AP multi-link device recommends for service transmission to be initiated (acquired) by the AP multi-link device can be determined based on the link service indication list subfields of the multi-link service element. Each link service indication list subfield can include n link service indication bitmap subfields. Here, n is the sum of the number of bits set to 1 in one or more first bits and the number of bits set to 1 in one or more second bits. Furthermore, each of the n link service indication bitmap subfields can be mapped to the non-AP multi-link device corresponding to one or more first bits set to 1 and the non-AP station corresponding to one or more second bits set to 1, respectively. Additionally, multiple link IDs can be mapped in ascending order to the bits of the link service indication bitmap subfields mapped to the non-AP multi-link devices.

[0425] Furthermore, the link service indication bitmap subfields of non-AP stations mapped to bits that are set to 1 among one or more second bits can be set to reserved bits. In this case, the value of the reserved bit may be 0.

[0426] If a non-AP multi-link device successfully performs TID-to-link mapping with an AP multi-link device, and none of the TIDs are mapped to all links, then the service indication bitmap subfields of each link mapped to the non-AP multi-link device can indicate whether services for the non-AP multi-link device are cached on each of the multiple links. Furthermore, when the default mapping is applied to links between a non-AP multi-link device and an AP multi-link device, the service indication bitmap subfields of each link mapped to the non-AP multi-link device can indicate which of the multiple links the non-AP multi-link device is recommended to use for guiding service transmission. In this case, the default mapping allows all TIDs to be mapped to all links.

[0427] In the bits of the link service indication bitmap subfield mapped to non-AP multi-link devices, the bits corresponding to links not configured on either the AP multi-link device or the non-AP multi-link device can be set to reserved bits. Furthermore, in the bits of the link service indication bitmap subfield mapped to non-AP multi-link devices, the bits corresponding to disabled links on the non-AP multi-link device can be set to reserved bits. In this case, a disabled link can be a link where uplink and downlink transmissions are suspended.

[0428] The specific subfields of the service indication list for each link of a multi-link service element can be referenced. Figures 13 to 18 Described Examples

[0429] As described above, the present invention has been illustrated using a wireless LAN as an example; however, the invention is not limited thereto and can also be applied to other communication systems such as cellular communication. Furthermore, although the methods, apparatus, and systems of the present invention have been described with reference to specific embodiments, some or all of the requirements and operations of the invention can be implemented using a computer system with a general-purpose hardware architecture.

[0430] The features, structures, effects, etc., described in the above embodiments are included in at least the embodiments of the present invention, but are not necessarily limited to the embodiments. Furthermore, the features, structures, effects, etc., described in the various embodiments can be implemented by those skilled in the art in combination or modification of other embodiments. Therefore, content related to such combinations and modifications should be interpreted as being included within the scope of the present invention.

[0431] The foregoing description focuses on embodiments, but these are merely illustrative and do not limit the invention. Those skilled in the art should understand that various modifications and applications not illustrated above can be made without departing from the essential characteristics of these embodiments. For example, the constituent elements specifically shown in the embodiments can be implemented through modifications. Furthermore, differences related to such modifications and applications should be interpreted as being included within the scope of the invention as defined in the appended claims.

Claims

1. A non-access point (non-AP) multi-link device, comprising multiple stations operating on multiple links respectively, wherein the non-AP multi-link device includes: transceiver; as well as processor, Wherein, the processor: Receive beacon frames from the AP multilink device, including Service Indication Map (TIM) elements and multilink service elements; Based on a partial virtual bitmap subfield of the TIM element, it is determined whether the service for the non-AP multi-link device is cached on the AP multi-link device. The partial virtual bitmap subfield includes one or more first bits and one or more second bits. A bit set to 1 among the one or more first bits indicates that the service for the non-AP multi-link device corresponding to that bit is cached on the AP multi-link device. Furthermore, a bit set to 1 among the one or more second bits indicates whether the service for a non-AP station not affiliated with any multi-link device, corresponding to that bit, is cached on the AP multi-link device. When a service intended for a non-AP multi-link device is cached on an AP multi-link device, based on the link service indication list subfields of the multi-link service element, it is determined which link among the multiple links the service intended for the non-AP multi-link device is cached on, or which link among the multiple links the AP multi-link device recommends the non-AP multi-link device to obtain service transmission on. The link service indication list subfield includes n link service indication bitmap subfields. Where n is equal to the sum of the number of bits set to 1 in the one or more first bits and the number of bits set to 1 in the one or more second bits. Wherein, each of the n link service indication bitmap subfields is respectively mapped to the non-AP multi-link device corresponding to the bit set to 1 in the one or more first bits and the non-AP station corresponding to the bit set to 1 in the one or more second bits, and The link service indication bitmap subfield of the non-AP station, which is mapped to the bit that is set to 1 in one or more of the second bits, is configured as a reserved bit.

2. The non-AP multi-link device according to claim 1, wherein, The value of the reserved bit is 0.

3. The non-AP multi-link device according to claim 1, wherein, When the non-AP multi-link device and the AP multi-link device successfully perform service identifier (TID) to link mapping, and not all TIDs are mapped to all links in the TID to link mapping, the service indicator bitmap subfield of each link mapped to the non-AP multi-link device indicates whether the service for the non-AP multi-link device is cached on each of the multiple links. When the default mapping is applied to the link between the non-AP multi-link device and the AP multi-link device, the link service indication bitmap subfield mapped to the non-AP multi-link device indicates which of the multiple links is recommended for the non-AP multi-link device to guide service transmission, and The default mapping is a mapping where all TIDs are mapped to all links.

4. The non-AP multi-link device according to claim 3, wherein, In the bits of each link service indication bitmap subfield mapped to the non-AP multi-link device, the bits corresponding to links not set by the AP multi-link device or the non-AP multi-link device are set as reserved bits.

5. The non-AP multi-link device according to claim 3, wherein, In the bits of each link service indication bitmap subfield mapped to the non-AP multi-link device, the bits corresponding to the disabled links of the non-AP multi-link device are set as reserved bits, and The disabled link is a link in which both uplink and downlink transmissions are suspended.

6. The non-AP multi-link device according to claim 1, wherein, The identifiers IDs of the multiple links are mapped in ascending order to the bits of the link service indication bitmap subfield mapped to the non-AP multi-link device.

7. The non-AP multi-link device according to claim 1, wherein, When the AP sending the beacon frame in the AP multilink device does not belong to the Multiple Basic Service Set Identifier (BSSID) set, the range of values ​​that the AP multilink device can allocate as the Association ID (AID) is determined based on the value of the Group Addressing Unit (BU) Indicator Index subfield. The value of the Group Addressing BU Indicator Index subfield indicates the number of bits used to indicate the group addressing frame that is cached and corresponds to an AP in the AP multilink device that is different from the AP that sent the beacon frame.

8. The non-AP multi-link device according to claim 7, wherein, When the AP sending the beacon frame in the AP multi-link device belongs to a multiple BSSID set, the range of values ​​that the AP multi-link device can allocate as AIDs is determined based on the value of the Group Addressing BU Indicator Index subfield and the bitmap limit. The bitmap limit is 48 bits.

9. An access point (AP) multi-link device, comprising multiple stations operating on multiple links respectively, the AP multi-link device comprising: transceiver; as well as processor, Wherein, the processor: Configure the beacon frame to be sent to non-AP multilink devices to include a Service Indication Map (TIM) element and a multilink service element. The TIM element includes a partial virtual bitmap subfield, which includes one or more first bits and one or more second bits. The bits set to 1 in the one or more first bits indicate that the service of the non-AP multilink device corresponding to the bit in the one or more first bits is cached on the AP multilink device. The bits set to 1 in the one or more second bits indicate whether the service of the non-AP station that is not attached to any multilink device corresponding to the bit in the one or more second bits is cached on the AP multilink device. When services for the non-AP multi-link device are cached on the AP multi-link device, based on which link among the multiple links the services for the non-AP multi-link device are cached on, or which link among the multiple links the AP multi-link device recommends the non-AP multi-link device to obtain service transmission on, the link service indication list subfields of the multi-link service element are set; and The transceiver is used to send the beacon frame. The link service indication list subfield includes n link service indication bitmap subfields. Where n is equal to the sum of the number of bits set to 1 in the one or more first bits and the number of bits set to 1 in the one or more second bits. Wherein, each of the n link service indication bitmap subfields is respectively mapped to the non-AP multi-link device corresponding to the bit set to 1 in the one or more first bits and the non-AP station corresponding to the bit set to 1 in the one or more second bits, and The link service indication bitmap subfield of the non-AP station, which is mapped to the bit that is set to 1 in one or more of the second bits, is configured as a reserved bit.

10. The AP multi-link device according to claim 9, wherein, The value of the reserved bit is 0.

11. The AP multi-link device according to claim 9, wherein, When the non-AP multi-link device and the AP multi-link device successfully perform service identifier (TID) to link mapping, and not all TIDs are mapped to all links in the TID to link mapping, the service indicator bitmap subfield of each link mapped to the non-AP multi-link device indicates whether the service for the non-AP multi-link device is cached on each of the multiple links. When the default mapping is applied to the link between the non-AP multi-link device and the AP multi-link device, the link service indication bitmap subfield mapped to the non-AP multi-link device indicates which of the multiple links is recommended for the non-AP multi-link device to guide service transmission, and The default mapping is a mapping where all TIDs are mapped to all links.

12. The AP multi-link device according to claim 11, wherein, The processor: The bits in the link service indication bitmap subfield mapped to the non-AP multi-link device that correspond to the links not set in the AP multi-link device or the non-AP multi-link device are set as reserved bits.

13. The AP multi-link device according to claim 11, wherein, The processor: The bits corresponding to the disabled links of the non-AP multi-link device in the link service indication bitmap subfield mapped to each link of the non-AP multi-link device are set as reserved bits. The disabled link is a link in which uplink and downlink transmissions are suspended.

14. The AP multi-link device according to claim 11, wherein, The identifiers IDs of the multiple links are mapped in ascending order to the bits of the link service indication bitmap subfield mapped to the non-AP multi-link device.

15. The multi-link device according to claim 9, wherein, When the AP sending the beacon frame in the AP multilink device does not belong to the Multiple Basic Service Set Identifier (BSSID) set, the range of values ​​that the AP multilink device can allocate as the Association ID (AID) is determined based on the value of the Group Addressing Unit (BU) Indicator Index subfield. The value of the Group Addressing BU Indicator Index subfield indicates the number of bits used to indicate the group addressing frame that is cached and corresponds to an AP in the AP multilink device that is different from the AP that sent the beacon frame.

16. The AP multi-link device according to claim 15, wherein, When the AP sending the beacon frame in the AP multi-link device belongs to a multiple BSSID set, the range of values ​​that the AP multi-link device can allocate as AIDs is determined based on the value of the Group Addressing BU Indicator Index subfield and the bitmap limit. The bitmap limit is 48 bits.

17. An operation method for a non-access point (non-AP) multi-link device, the non-AP multi-link device comprising multiple stations operating on multiple links respectively, the operation method comprising the following steps: Receive beacon frames from the AP multilink device, including Service Indication Map (TIM) elements and multilink service elements; Based on a partial virtual bitmap subfield of the TIM element, it is determined whether the service for the non-AP multi-link device is cached on the AP multi-link device. The partial virtual bitmap subfield includes one or more first bits and one or more second bits. A bit set to 1 among the one or more first bits indicates that the service for the non-AP multi-link device corresponding to that bit is cached on the AP multi-link device. Furthermore, a bit set to 1 among the one or more second bits indicates whether the service for a non-AP station not affiliated with any multi-link device, corresponding to that bit, is cached on the AP multi-link device. When a service intended for a non-AP multi-link device is cached on an AP multi-link device, based on the link service indication list subfields of the multi-link service element, it is determined which link among the multiple links the service intended for the non-AP multi-link device is cached on, or which link among the multiple links the AP multi-link device recommends the non-AP multi-link device to obtain service transmission on. The link service indication list subfield includes n link service indication bitmap subfields. Where n is equal to the sum of the number of bits set to 1 in the one or more first bits and the number of bits set to 1 in the one or more second bits. Wherein, each of the n link service indication bitmap subfields is respectively mapped to the non-AP multi-link device corresponding to the bit set to 1 in the one or more first bits and the non-AP station corresponding to the bit set to 1 in the one or more second bits, and The link service indication bitmap subfield of the non-AP station, which is mapped to the bit that is set to 1 in one or more of the second bits, is configured as a reserved bit.

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