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

Abstract

The present invention relates to a wireless communication method using multiple links and a wireless communication terminal using the same. A multi-link apparatus using a plurality of links is disclosed. The processor receives, on any one of the plurality of links, a first physical layer protocol data unit (PPDU) including access category (AC) restriction signaling and reverse (RD) grant from a station that is a transmission opportunity (TXOP) holder or a service cycle (SP) source; the second PPDU is transmitted to the station as a response to the first PPDU based on the AC restriction signaling over any one of the links. The AC restriction signaling indicates a traffic identifier (TID) of a frame included in the second PPDU or whether the AC is restricted.

Description

[0001] This application is a divisional application of patent application No. 202180046525.7 (International Application No. PCT / KR2021 / 008310), filed on December 28, 2022, with an international application date of June 30, 2021, entitled "A wireless communication method using multiple links and a wireless communication terminal using the method". Technical Field

[0002] This invention relates to a wireless communication method using multiple links and a wireless communication terminal using the method. Background Technology

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

[0004] Since supporting the initial wireless LAN technology using the 2.4 GHz frequency, the Institute of Electrical and Electronics Engineers (IEEE) 802.11 has commercialized or developed various technical standards. First, IEEE 802.11b supported a maximum communication speed of 11 Mbps when using the 2.4 GHz band. Compared to the significantly congested 2.4 GHz band, IEEE 802.11a, commercialized after IEEE 802.11b, uses the 5 GHz band instead of the 2.4 GHz band to reduce interference and increases the communication speed to a maximum of 54 Mbps through the use of orthogonal frequency division multiplexing (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 has attracted significant attention for using the 2.4 GHz frequency band to achieve a maximum communication speed of 54 Mbps and meeting backward compatibility requirements. Moreover, it is superior to IEEE 802.11a in terms of communication range.

[0005] Furthermore, IEEE 802.11n has been developed as a technical standard to overcome the limitations of communication speed, a weakness identified in wireless LANs. IEEE 802.11n aims to improve network speed and reliability and extend the operating range of wireless networks. More specifically, IEEE 802.11n supports High Throughput (HT), with data processing speeds of up to 540 Mbps or higher, and further, it is based on Multiple Inputs and 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 transmits multiple duplicate copies to increase data reliability.

[0006] With the activation of the wireless LAN supply, and further, with the diversification of applications using wireless LAN, the need for new wireless LAN systems supporting higher throughput (Very High Throughput, VHT) than those supported by IEEE 802.11n has gained attention. Among these, IEEE 802.11ac supports wide bandwidth (80 to 160 MHz) in the 5 GHz frequency band. The IEEE 802.11ac standard is defined only in the 5 GHz band, but initial 11ac chipsets even support operation in the 2.4 GHz band for backward compatibility with existing 2.4 GHz band products. Theoretically, according to this standard, wireless LAN speeds of at least 1 Gbps can be achieved across multiple stations, and maximum single-link speeds of at least 500 Mbps can be achieved. This is achieved through concepts that expand the wireless interface accepted 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 60 GHz band instead of the existing 2.4 GHz / 5 GHz band. IEEE 802.11ad is a transmission standard that provides speeds up to 7 Gbps 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 60 GHz band is difficult to penetrate obstacles, limiting its use to devices operating in close proximity.

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

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

[0009] Technical issues

[0010] The purpose of one embodiment of the present invention is to provide a wireless communication method using multiple links and a wireless communication terminal using the method.

[0011] Technical solution

[0012] According to an embodiment of the present invention, a multi-link device using multiple links includes a transceiver and a processor. The processor receives, on any one of the multiple links, a first physical layer protocol data unit (PPDU) including access category (AC) restriction signaling and reverse direction (RD) permission from a station acting as a transmission opportunity (TXOP) holder or service period (SP) source; and on any one of the links, sends a second PPDU to the station as a response to the first PPDU based on the AC restriction signaling. The AC restriction signaling indicates whether the traffic identifier (TID) or AC of the frame included in the second PPDU is restricted.

[0013] An AC or TID is mapped to any one of the plurality of links, and the multi-link device can transmit frames based on the AC or TID mapped to any of the links. In this case, the processor: if the AC restriction signaling indicates that the TID of the data frame included in the second PPDU is allowed to be any TID and the multi-link device includes the data frame in the second PPDU, it may not include the data frame corresponding to the TID not mapped to any of the links in the second PPDU, and may include the data frame corresponding to the TID mapped to any of the links in the second PPDU.

[0014] An AC or TID is mapped to any one of the plurality of links, and the multi-link device can transmit frames based on the AC or TID mapped to any one of the links. In this case, the processor: if the AC restriction signaling indicates that the AC or TID of the frame included in the second PPDU is restricted and the multi-link device includes the data frame in the second PPDU, it may not include the data frame corresponding to a TID or AC that is not mapped to any of the links or has a lower priority than the AC or TID of the frame received from the station in the second PPDU, and may include the data frame corresponding to a TID or AC that is mapped to any of the links and has a priority equal to or higher than the AC or TID of the frame received from the station in the second PPDU.

[0015] When the multi-link device receives multiple frames from the station, the priority of the AC or TID of the frames received from the station can be the lowest priority among the multiple frame priorities.

[0016] The processor can treat the AC of the management frame as a predetermined value.

[0017] When the multi-link device includes a BlockAck frame in the second PPDU, the processor can determine the AC of the BlockAck frame based on the TID field of the BlockAck frame. Similarly, when the multi-link device includes a BlockAckReq frame in the second PPDU, the processor can determine the AC of the BlockAckReq frame based on the TID field of the BlockAckReq frame.

[0018] The AC restriction signaling may be included in the media access control (MAC) header of the frame included in the PPDU that includes the RD license.

[0019] According to an embodiment of the present invention, an operation method of a multi-link device using multiple links includes the following steps: on any one of the multiple links, receiving a first physical layer protocol data unit (PPDU) including access category (AC) restriction signaling and reverse direction (RD) permission from a station that is a transmission opportunity (TXOP) holder or service period (SP) source; and on any one of the links, sending a second PPDU to the station as a response to the first PPDU based on the AC restriction signaling. The AC restriction signaling indicates whether the traffic identifier (TID) or AC of the frame included in the second PPDU is restricted.

[0020] An AC or TID is mapped to any one of the plurality of links, and the multi-link device can send frames based on an AC or TID mapped to any of the links. In this case, the step of sending the second PPDU to the station includes the following steps: if the AC restriction signaling indicates that the TID of the data frame included in the second PPDU is allowed to be any TID and the multi-link device includes the data frame in the second PPDU, then, if the AC restriction signaling indicates that the TID of the data frame included in the second PPDU is allowed to be any TID, then, if the multi-link device includes the data frame in the second PPDU, then, if the data frame corresponding to the TID not mapped to any of the links is included in the second PPDU, then, if the data frame corresponding to the TID mapped to any of the links is included in the second PPDU.

[0021] An AC or TID is mapped to any one of the plurality of links, and the multi-link device can send frames based on an AC or TID mapped to any one of the links. The step of sending the second PPDU to the station includes the following steps: if the AC restriction signaling indicates that the AC or TID of a frame included in the second PPDU is restricted and the multi-link device includes a data frame in the second PPDU, the data frame corresponding to a TID or AC that is not mapped to any of the links or has a lower priority than the AC or TID of the frame received from the station is not included in the second PPDU, and the data frame corresponding to a TID or AC that is mapped to any of the links and has a priority equal to or higher than the AC or TID of the frame received from the station is included in the second PPDU.

[0022] When the multi-link device receives multiple frames from the station, the priority of the AC or TID of the frames received from the station can be the lowest priority among the multiple frame priorities.

[0023] The step of sending the second PPDU to the station may include the following steps: treating the AC of the management frame as a predetermined value.

[0024] The step of sending the second PPDU to the station may include the following steps: if the multi-link device includes a BlockAck frame in the second PPDU, determining the AC of the BlockAck frame based on the TID field of the BlockAck frame; and if the multi-link device includes a BlockAckReq frame in the second PPDU, determining the AC of the BlockAckReq frame based on the TID field of the BlockAckReq frame. The AC restriction signaling may be included in the medium access control (MAC) header of the frame included in the PPDU that includes the RD grant.

[0025] Beneficial effects

[0026] An embodiment of the present invention provides a wireless communication method for efficiently using multiple links and a wireless communication terminal using the method. Attached Figure Description

[0027] Figure 1 The illustration shows a wireless LAN system according to an embodiment of the present invention.

[0028] Figure 2 The illustration shows a wireless LAN system according to another embodiment of the present invention.

[0029] Figure 3 The illustration shows the configuration of a station according to an embodiment of the present invention.

[0030] Figure 4 The diagram illustrates the configuration of an access point according to an embodiment of the present invention.

[0031] Figure 5 This diagram illustrates the process of setting up a link between a station and an access point.

[0032] Figure 6 The diagram illustrates the Carrier Sense Multiple Access (CSMA) / Collision Avoidance (CA) method used in wireless LAN communication.

[0033] Figure 7Examples of physical layer protocol dataunit (PPDU) formats according to various standard generations are shown.

[0034] Figure 8 Examples of various Extremely High Throughput (EHT) Physical Protocol Data Unit (PPDU) formats and their indication methods according to embodiments of the present invention are shown.

[0035] Figure 9 A multi-link device according to an embodiment of the present invention is shown.

[0036] Figure 10 This illustration shows frame exchange between a non-AP multilink device and an AP multilink device with TID-to-link mapping configured according to an embodiment of the present invention.

[0037] Figure 11 This illustrates frame switching based on the reverse direction (RD) protocol according to an embodiment of the present invention.

[0038] Figure 12 An AC restriction signaling according to an embodiment of the present invention is shown.

[0039] Figure 13 The frame format and the format of the signaling field of the frame are shown according to an embodiment of the present invention.

[0040] Figure 14 An embodiment of the invention is shown, in which RD switching without AC restrictions is performed in a link with TID-to-link mapping.

[0041] Figure 15 Another embodiment of the invention is shown, in which RD switching without AC restrictions is performed in a link with TID-to-link mapping.

[0042] Figure 16 Another embodiment of the invention is shown, in which no AC limit is set when RD switching is performed in a link with TID-to-link mapping applied.

[0043] Figure 17 Another embodiment of the invention is shown, in which RD switching is performed when AC restrictions are applied in a link where TID-to-link mapping is applied.

[0044] Figure 18Another embodiment of the invention is shown, in which RD switching is performed when AC restrictions are applied in a link where TID-to-link mapping is applied.

[0045] Figure 19 An embodiment of the present invention illustrates how an RD initiator uses signals to notify information about AC restrictions used in an RD response.

[0046] Figure 20 An embodiment of the invention is shown in which RD switching is performed when a PPDU that has been synchronized upon completion of transmission is sent in multiple links.

[0047] Figure 21 The diagram illustrates a RU configuration that can be assigned to a station in IEEE 802.11ax and a RU configuration that can be assigned to a station according to an embodiment of the present invention.

[0048] Figure 22 The IEEE 802.11ax standard and the OFDMA DL PPDU used in embodiments of the present invention are shown.

[0049] Figure 23 The following is an illustration of an embodiment of the invention, showing the use of a sub-channel that is a non-20MHz main channel to perform a backoff process.

[0050] Figure 24 This illustrates a scenario where, according to an embodiment of the invention, a station successfully accesses a sub-channel that is not a 20MHz main channel and transmits a PPDU, but the length of the PPDU is limited.

[0051] Figure 25 An embodiment of the invention is shown, in which, when the 20MHz main channel is not idle, the station performs channel access through a sub-channel of a segment that is a non-main segment.

[0052] Figure 26 An embodiment of the invention is shown, in which a first AP of a multi-link device signals to a second AP that reception can be performed via a sub-channel that is not a 20MHz main channel.

[0053] Figure 27 The AP multi-link device shown according to an embodiment of the present invention allows a fallback process for uplink transmission to be performed in the segment where a station is docked in a segment other than the 80MHz main channel. Detailed Implementation

[0054] 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 certain cases, there are terms arbitrarily chosen by the applicant, and in such cases, their meaning will be described 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.

[0055] Throughout this specification, when describing an element as being "coupled" to another element, that element can be "directly coupled" to the other element or "electrically coupled" to the other element via a third element. Furthermore, unless explicitly stated otherwise, the word "comprising" will be understood to mean that it does not exclude any other elements but may include others. Additionally, limitations based on specific thresholds, such as "or above" or "or below," may be appropriately replaced by "greater than" or "less than," respectively.

[0056] In this invention, fields and subfields can be used interchangeably.

[0057] Figure 1 The illustration shows a wireless LAN system according to an embodiment of the present invention.

[0058] 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 (BSSs) and independent BSSs (IBSSs). Figure 1 The diagram shows the infrastructure BSS between them.

[0059] 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 as stations providing distribution services, and a distribution system (DS) connecting multiple access points AP-1 and AP-2.

[0060] A station (STA) is any device that includes Medium Access Control (MAC) and a Physical Layer interface for wireless media as defined by the IEEE 802.11 standard, and broadly includes both non-access point (non-AP) stations and access points (APs). Furthermore, in this specification, the term "terminal" is a term that can be used to refer to a non-AP STA, 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 to be 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 used for the station. According to the invention, "terminal" can be used as a term that includes user equipment (UE).

[0061] An Access Point (AP) is an entity that provides access to a Distributed System (DS) via wireless media for its associated stations. In a Base Station Service (BSS) infrastructure, communication between non-AP stations is generally performed via the AP; however, direct communication between non-AP stations is even permitted when a direct link is configured. In this invention, AP is used as a concept including Personal BSS Coordination Point (PCP), and broadly can include concepts such as a central controller, base station (BS), Node B, Base Transceiver System (BTS), or site controller. In this invention, AP can also be referred to as a base station wireless communication terminal. The term "base station wireless communication terminal" can be broadly used to include AP, base station, eNB (eNodeB), and transmission point (TP). Furthermore, in communication with multiple wireless communication terminals, a base station wireless communication terminal can include various types of wireless communication terminals that allocate communication medium resources and perform scheduling.

[0062] 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).

[0063] 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.

[0064] Because in Figure 2 The BSS3 shown in the diagram is an independent BSS and does not include an access point (AP). Therefore, 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 connected to each other.

[0065] Figure 3 This is a block diagram illustrating the configuration of a station 100 according to an embodiment of the present invention. As shown, 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.

[0066] 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 may be implemented independently, or multiple modules may 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.

[0067] 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 means, and the processor 110 can control the station 100 based on the received user input. In addition, the user interface unit 140 can execute the output of commands based on the processor 110 using various output means.

[0068] Next, the display unit 150 outputs an image on the display screen. The display unit 150 can output various display objects, such as content executed by the processor 110 or a user interface based on control commands from the processor 110. 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.

[0069] 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 those 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 sent 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 thereof will be described below.

[0070] 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 integrated into a single chip or implemented 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, may be selectively provided in the station 100.

[0071] Figure 4 This is a block diagram illustrating the configuration of an AP 200 according to an embodiment of the present invention. (As shown in...) Figure 4 As illustrated in the figure, the AP 200 according to an embodiment of the present invention may include a processor 210, a communication unit 220, and a memory 260. Figure 4 In the configuration of AP200, and Figure 3 The configuration of station 100 is the same or corresponds to Figure 3 Repeated descriptions of the configuration of station 100 will be omitted.

[0072] refer to Figure 4 The AP 200 according to the invention includes a communication unit 220 that operates a BSS in at least one frequency band. (As in...) Figure 3 As described in the embodiments, the communication unit 220 of AP 200 may also include multiple communication modules using different frequency bands. That is, AP 200 according to embodiments of the present invention may together include two or more communication modules in different frequency bands (e.g., 2.4 GHz, 5 GHz, 6 GHz, and 60 GHz). Preferably, AP 200 may include communication modules using frequency bands of 7.125 GHz or higher, and communication modules using frequency bands of 7.125 GHz or lower. Each communication module may perform wireless communication with the station according to the wireless LAN standard of the frequency band supported by the respective communication module. Communication unit 220 may operate only one communication module at a time, or operate multiple communication modules simultaneously, depending on the performance and requirements of AP 200. In embodiments of the present invention, communication unit 220 may represent an RF communication module for processing radio frequency (RF) signals.

[0073] Next, memory 260 stores control programs and various data used in AP 200. The control programs may include access programs 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 send 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 requests of stations. 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.

[0074] Figure 5 It is a diagram illustrating the process of configuring the link between the station and the access point.

[0075] refer to Figure 5In a broad sense, the link between STA 100 and AP 200 is set up through three steps: scanning, authentication, and association. First, the scanning step is where STA 100 obtains access information from the BSS operated by AP 200. Methods for performing the scan include passive scanning, where AP 200 obtains information by periodically sending beacon messages (S101), and active scanning, where STA 100 sends a probe request to AP (S103) and obtains access information by receiving a probe response from AP (S105).

[0076] STA 100, having successfully received wireless access information during the scanning step, performs an authentication step by sending an authentication request (S107a) and receiving an authentication response from AP 200 (S107b). After performing the authentication step, STA 100 performs an association step by sending an association request (S109a) and receiving an association response from AP 200 (S109b). In this specification, association primarily refers to wireless association; however, the invention is not limited thereto, and association can broadly include both wireless and wired associations.

[0077] Meanwhile, the 802.1X-based authentication step (S111) and the IP address acquisition step via DHCP (S113) can be performed separately. Figure 5 In this context, authentication server 300 is the server that handles 802.1X-based authentication with STA 100, and can exist in physical association with AP 200 or as a standalone server.

[0078] Figure 6 This is a diagram illustrating the Carrier Sense Multiple Access (CSMA) / Collision Avoidance (CA) method used in wireless LAN communication.

[0079] Terminals performing wireless LAN communication check if a channel is busy by performing carrier sensing before transmitting data. When a wireless signal with a predetermined 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 detected in the corresponding channel, or when a wireless signal with a strength less than the CCA threshold is detected, the channel is determined to be idle.

[0080] 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 (e.g., Arbitration IFS, PCF IFS, etc.) depending on the terminal's situation. 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 decreasing a slot time equal to the length of a random number determined by the corresponding terminal, and terminals that have completely exhausted their 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. In this case, the random number can be called a backoff counter. That is, the terminal sets the initial value of the backoff counter based on the obtained random number integer. When a terminal detects that the channel is idle during the slot time, the terminal can decrement the backoff counter by 1. Furthermore, when the backoff counter reaches 0, the terminal can be allowed to perform channel access in that channel. Therefore, if the channel is idle during the AIFS period and the slot time of the backoff counter, the terminal's transmission can be permitted.

[0081] When a specific terminal successfully accesses a channel, it can transmit data through the channel. However, when a terminal attempting to access a channel conflicts with another terminal, the conflicting terminals are each assigned a new random number to perform a fallback process again. According to an embodiment, the new random number assigned 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 to access the channel again by performing the fallback process in the next contention window interval, and in this case, each terminal begins the fallback process from the remaining time slot time in the previous contention window interval. In this way, terminals performing wireless LAN communication can avoid mutual conflicts on specific channels.

[0082] <Examples of various PPDU formats>

[0083] Figure 7 The illustration shows an example of the format of the PLCP Protocol Data Unit (PPDU) used in each of the various standard generations. More specifically, Figure 7 The illustration in (a) is based on an embodiment of the conventional PPDU format of 802.11a / g. Figure 7 The illustration in (b) is based on an embodiment using 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 L-SIG and RL-SIG, which are commonly used in the PPDU format.

[0084] refer to 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.

[0085] refer to Figure 7(b) The HE PPDU preamble also includes, in a conventional preamble, a Repeated Legacy Short Training field (RL-SIG), a High Efficiency Signal A field (HE-SIG-A), a High Efficiency Signal B field (HE-SIG-B), a High Efficiency Short Training field (HE-STF), and a High Efficiency Long Training field (HE-LTF). In embodiments of the present invention, RL-SIG, HE-SIG-A, HE-SIG-B, HE-STF, and HE-LTF can be referred to as HE preambles. The detailed configuration of the HE preamble can be modified according to the HE PPDU format. For example, HE-SIG-B can be used only in the HE MU PPDU format.

[0086] refer to 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.

[0087] 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, so 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.

[0088] refer to 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 code rates 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.

[0089] The L_LENGTH field is in bytes and is allocated a total of 12 bits, allowing for signaling up to 4095 signals. It can be combined with the L_RATE field to indicate the length of the PPDU. Traditional and non-traditional terminals may interpret the L_LENGTH field differently.

[0090] First, traditional or non-traditional terminals interpret the length of the PPDU using the L_LENGTH field as follows. When the L_RATE field is set to 6 Mbps, 3 bytes (i.e., 24 bits) can be transmitted within 4 µs, where 4 µs is the duration of one symbol in a 64 FFT. Therefore, the number of symbols based on 64 FFT after L-SIG is obtained by adding the 3 bytes corresponding to the SVC field and the tail field to the value of the L_LENGTH field and dividing by the 3 bytes of transmission as a symbol. The length of the corresponding PPDU, i.e., the receive time (RXTIME), is obtained by multiplying the obtained number of symbols by 4 µs as a symbol duration and then adding the 20 µs used for transmitting L-STF, L-LTF, and L-SIG. This can be represented by the following Equation 1.

[0091] [Equation 1]

[0092]

[0093] at this time, 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 5.484 ms. Non-traditional terminals sending PPDUs should set the L_LENGTH field as shown in Equation 2 below.

[0094] [Equation 2]

[0095]

[0096] Here, TXTIME is the total transmission time that constitutes the corresponding PPDU, and is represented by Equation 3 below. In this case, TX represents the transmission time of X.

[0097] [Equation 3]

[0098]

[0099] Referring to the equation above, the length of the PPDU is calculated based on the up-rounded value of L_LENGTH / 3. Therefore, for a random value k, three different values ​​of L_LENGTH={3k+1, 3k+2, 3(k+1)} indicate the same PPDU length.

[0100] refer to Figure 7 (e) The Universal SIG (U-SIG) field continues to exist in EHT PPDUs and subsequent generations of WLAN PPDUs, and is used to distinguish which generation the PPDU belongs to, including 11be. U-SIG is an OFDM 2 symbol based on 64 FFT 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 mainly divided into Version Independent (VI) and Version Dependent (VD) fields.

[0101] 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 distinguish 11be from subsequent generations of wireless LAN standards by version. 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 sent in the MAC header. The length of the TXOP included in the PPDU can be inferred by adding the TXOP to the PHY header without having to decode the MPDU, and the TXOP has a value of 7 bits or more.

[0102] The VD field contains signaling information useful only for PPDUs of version 11be, and can include fields common to any PPDU format such as PPDU format and BW, as well as fields defined differently for each PPDU format. The PPDU format is a classifier that categorizes EHT Single User (SU), EHT Multiple User (MU), EHT Trigger-based (TB), and EHT Extended Range (ER) PPDUs. The BW field signals five basic PPDU BW options at 20, 40, 80, 160 (80+80), and 320 (160+160) MHz (a BW that can be expressed as a power of 20*2 is called a basic BW), as well as various remaining PPDU BWs configured via preamble puncturing. After signaling at 320 MHz, signaling can be signaled in some 80 MHz punctured form. The punctured and modified channel type can be signaled directly in the BW field, or it can be signaled using the BW field along with fields appearing after the BW field (e.g., fields within the EHT-SIG field). If the BW field is configured with 3 bits, a total of 8 BWs can be signaled, and therefore only a maximum of 3 punctured modes can be signaled. If the BW field is configured with 4 bits, a total of 16 BWs can be signaled, and therefore a maximum of 11 punctured modes can be signaled.

[0103] 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. The fields used to distinguish between MU PPDUs and SU PPDUs can be placed before the EHT-SIG field, and additional signaling can be performed for this purpose. Both SU PPDUs and MU PPDUs include the EHT-SIG field, but some fields that are not needed in the SU PPDU can be compressed. The information in the compressed fields 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, different configurations can be used, such as omitting or replacing common fields with EHT-SIG, replacing user-specific fields, or reducing the size to one.

[0104] Alternatively, the SU PPDU may also include a compression field indicating whether compression is performed, and some fields (e.g., the RA field, etc.) may be omitted depending on the value of the compression field.

[0105] 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 intended for simultaneous reception by multiple users, and therefore the EHT-SIG field must be transmitted after the U-SIG field, and the amount of information transmitted may vary. That is, since multiple MU PPDUs are sent to multiple STAs, 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 sent to the STA itself. Therefore, the AP must transmit this information by including the aforementioned information in the EHT-SIG field. For this purpose, information for efficient transmission of the EHT-SIG field is signaled in the U-SIG field, and this may correspond to the MCS as a modulation method and / or the number of symbols in the EHT-SIG field. The EHT-SIG field may include information about the size and location of the RU assigned to each user.

[0106] In the case of SU PPDU, multiple RUs can be assigned to the STA, and these RUs can be consecutive or discontinuous. If the RUs assigned to the STA are discontinuous, the STA should identify the intermediate punched RUs in order to effectively receive the SUPPDU. Therefore, the AP can send a SU PPDU that includes information about the punched RUs among those assigned to the STA (e.g., the punching pattern of the RUs, etc.). That is, in the case of SU PPDU, a punching mode field can be included in the EHT-SIG field. This punching mode field includes information indicating the punching pattern in bitmap form and whether a punching mode has been applied, and the punching mode field can signal the type of discontinuous channel occurring within the bandwidth.

[0107] The types of discontinuous channels notified by signals are limited, and the BW and discontinuous channel information of the SUPPDU are indicated in combination with the value of the BW field. For example, a SU PPDU is a PPDU sent only to a single terminal, so that the STA can identify the bandwidth allocated to itself through the BW field included in the PPDU, and the SU PPDU can identify the punctured resources in the allocated bandwidth through the puncturing mode field of the U-SIG field or EHT-SIG field included in the PPDU. In this case, the terminal can receive the PPDU in the remaining resource units after excluding the specific channels of the punctured resource units. At this time, the multiple RUs allocated to the STA can be configured by different frequency bands or tones.

[0108] To reduce the signaling overhead of the SU PPDU, only a limited number of discontinuous channel types are signaled. Puncture could be performed on each 20MHz sub-channel. Therefore, if puncturing is performed on a BW (such as 80, 160, and 320MHz) with multiple 20MHz sub-channels, in the case of 320MHz, the discontinuous channel type (punch-through of only the edge 20MHz is considered discontinuous) should be signaled by indicating whether each of the remaining 15 20MHz sub-channels after excluding the primary channel is used. Thus, allocating 15 bits to signal the discontinuous channel type transmitted by a single user might constitute excessive signaling overhead, given the low transmission rate of the signaling portion.

[0109] 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.

[0110] Furthermore, in embodiments of the present invention, a technique is proposed for configuring the PPDU indicated by the preamble piercing (BW) value differently depending on the PPDU format notified by signaling in the PPDU format field. Assuming the BW field is 4 bits long, 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 solely through the BW field of U-SIG. However, in the case of EHT MU PPDU, EHT-SIG-B is notified by signaling after U-SIG, thus allowing up to 11 piercing modes to be signaled in a different way than the SU PPDU method. In the case of EHT ER PPDU, the BW field can be configured to 1 bit to signal whether the EHT ERPPDU uses a 20MHz or 10MHz band PPDU.

[0111] Figure 7 (f) illustrates the configuration of the format-specific fields of the VD field when an EHT MU PPDU is indicated in the PPDU format field of the U-SIG. In the case of a MU PPDU, SIG-B is necessary; it is a signaling field used for simultaneous reception by multiple users and can be sent after U-SIG without a separate SIG-A. Therefore, information for decoding SIG-B should be signaled in the U-SIG. These fields include SIG-B MCS, SIG-BDCM, the number of SIG-B symbols, SIG-B compression, and the number of EHT-LTF symbols, etc.

[0112] 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.

[0113] Reference Figure 8 A PPDU can consist of a preamble and a data portion, and the format of an EHT PPDU as a PPDU type can be distinguished 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 in the format of an EHT PPDU.

[0114] Figure 8(a) shows an example of the EHT SU PPDU format for a single STA. The EHT SU PPDU is a PPDU used for single-user (SU) transmissions between an AP and a single STA, and the EHT-SIG-A field for additional signaling can be located after the U-SIG field.

[0115] Figure 8 (b) shows an example of the EHT trigger-based PPDU format corresponding to the EHT PPDU transmitted based on a trigger frame. The EHT trigger-based PPDU is an EHT PPDU transmitted based on a trigger frame and is an uplink PPDU used in response to the trigger frame. Unlike the EHT SU PPDU, the EHT-SIG-A field in the EHT PPDU does not follow the U-SIG field.

[0116] Figure 8 (c) shows an example of an EHT MU PPDU format corresponding to an EHT PPDU for multiple users. An EHT MU PPDU is a PPDU used to send PPDUs to one or more STAs. In the EHT MU PPDU format, the HE-SIG-B field may follow the U-SIG field.

[0117] Figure 8 (d) shows an example of the EHT ERSU PPDU format, which is used for transmission with a single user across an extended range of STAs. Figure 8 Compared to the EHT SU PPDU described in (a), the EHT ER SU PPDU can be used for single-user transmission with a wider range of STAs, and the U-SIG field can be repeatedly positioned on the time axis.

[0118] Figure 8 The EHT MU PPDU described in (c) can be used by the AP to perform downlink transmissions to multiple STAs. Here, the EHT MU PPDU may include scheduling information, enabling multiple STAs to simultaneously receive PPDUs sent from the AP. The EHT MU PPDU may convey the AID information of the receiver and / or sender of the transmitted PPDU to the STA via the user-specific field of EHT-SIG-B. Therefore, multiple terminals receiving the EHT MU PPDU can perform spatial reuse operations based on the AID information included in the user-specific field in the preamble of the received PPDU.

[0119] Specifically, the resource unit allocation (RA) field in the HE-SIG-B field included in the HE MU PPDU can include information about the configuration (e.g., the partitioning of resource units) of resource units within a specific bandwidth (e.g., 20MHz) of the frequency axis. That is, 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 each partitioned resource unit.

[0120] For example, the user field corresponding to at least one resource unit among the multiple 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.

[0121] For ease of description, in this specification, the terms "frame" or "MAC frame" may be used interchangeably with "MPDU".

[0122] 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 be configured as a single wireless medium capable of transmitting MAC service data units (MSDUs). For example, when the frequency band of any link is used by another wireless communication device, the wireless communication device can continue communicating through another link. As mentioned above, the wireless communication device can effectively use multiple channels. Furthermore, when a wireless communication device uses multiple links to perform communication simultaneously, the total throughput can be increased. However, in existing wireless LANs, a single wireless communication device is specified to use only one link. Therefore, a method for operating a wireless local area network (WLAN) using multiple links is needed. (Refer to...) Figures 9 to 26 This describes a wireless communication method for a wireless communication device using multiple links. First, it will refer to... Figure 9 Describe the specific structure of a wireless communication device that uses multiple links.

[0123] Figure 9 A multi-link device according to an embodiment of the present invention is shown.

[0124] A multi-link device (MLD) can be defined for the aforementioned wireless communication method using multiple links. A multi-link device can be a device with one or more affiliated stations. According to embodiments of the invention, a multi-link device can be 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 configuration elements. In this case, the multi-link device can be a logical entity. Specifically, the multi-link device can include 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) up to the logical link control (LLC). Furthermore, the MLD can have a MAC data service.

[0125] 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 different links or different channels. For example, multiple stations included in a multi-link device can operate on different channels at 2.4 GHz, 5 GHz, and 6 GHz.

[0126] The operation of a multi-link device can be referred to as multi-link operation, MLD operation, or multi-band operation. Furthermore, when the slave station in a multi-link device is an Access Point (AP), the multi-link device can be called an AP MLD. Conversely, when the slave station in a multi-link device is a non-AP station, the multi-link device can be called a non-AP MLD.

[0127] Figure 9The communication operations of non-AP MLD and AP-MLD are illustrated. Specifically, non-AP MLD and AP-MLD each use three links for communication. AP MLD includes a first AP (AP1), a second AP (AP2), and a third AP (AP3). Non-AP MLD includes a first non-AP station (non-AP STA1), a second non-AP station (non-AP STA2), and a third non-AP station (non-AP STA3). The first AP (AP1) and the first non-AP station (non-AP STA1) communicate with each other via the first link (link 1). Furthermore, the second AP (AP2) and the second non-AP station (non-AP STA2) communicate with each other via the second link (link 2). Additionally, the third AP (AP3) and the third non-AP station (non-AP STA) communicate with each other via the third link (link 3).

[0128] Multilink operation may include a multilink setup operation. Multilink setup corresponds to the association operation described above in single-link operation and can be performed first to exchange frames across multiple links. The multilink device can obtain the information required for setting up the multilink from a 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 the multiple devices included in the multilink device can simultaneously enable one device to transmit while another device performs reception. Furthermore, the capability information may include information about the links available to each station included in the MLD. Additionally, the capability information may include information about the channels available to each station included in the MLD.

[0129] Multi-link configuration can be set up 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 if multiple links are configured from the first to the third, multi-link configuration can still be performed using the first link.

[0130] In addition, a mapping between traffic identifiers (TIDs) and links can be configured. This will refer to... Figure 10 Describe it.

[0131] Figure 10 The present invention illustrates frame switching between a non-AP multilink device and an AP multilink device when TID-to-link mapping is set according to an embodiment of the present invention.

[0132] Specifically, frames corresponding to a specific TID value can be exchanged only through predetermined links. The mapping between TIDs and links can be set directionally. For example, when multiple links are set 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, and the second multi-link device can be configured to send frames with the second TID on the first link. Furthermore, the mapping between TIDs and links can have a default configuration. Specifically, when no additional settings are present in the multi-link setup, the multi-link device can exchange frames corresponding to TIDs on each link according to the default configuration. In this case, the default configuration could be to exchange all TIDs on any one link.

[0133] 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, TIDs can indicate traffic category (TC) and traffic stream (TS). Furthermore, TIDs can be divided into 16 categories. For example, a TID can be specified as any one of 0 to 15. TID values ​​can be specified differently based on 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), TID values ​​from 0 to 7 can be assigned. 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 values ​​can be assigned from 8 to 15. When using HCCA or SPCA, TID can represent TSID. Additionally, when using HEMM or SEMM, TID values ​​can be assigned from 8 to 15. When using HEMM or SEMM, TID can represent TSID.

[0134] User priority (UP) and access category (AC) can be mapped. AC can be a label used to provide QoS in EDCA. AC can also be a label used to indicate EDCA parameter sets. EDCA parameters or EDCA parameter sets are parameters used in channel contention within EDCA. QoS stations can use ACs to ensure QoS. Furthermore, ACs 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. AC_BK, AC_BE, AC_VI, and AC_VO can be classified as lower-level ACs. For example, AC_VI can be subdivided into AC_VI main items and AC_VI replacement items. Similarly, AC_VO can be subdivided into AC_VO main items and AC_VO replacement items. Additionally, UP or TID can be mapped to ACs. 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, AC_VI replacement, AC_VI main item, AC_VO main item, and AC_VO replacement item, respectively. Additionally, UP or TID 1, 2, 0, 3, 4, 5, 6, and 7 can have increasing priorities. That is, the area near 1 can have low priority, while the area near 7 can have 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 ACI (AC index) 0, 1, 2, and 3, respectively. Due to this characteristic of TIDs, the mapping between TIDs and links can represent the mapping between ACs and links. Similarly, the mapping between links and ACs can represent the mapping between TIDs and links.

[0135] As described above, a TID can be mapped to each of multiple links. This mapping can specify the links capable of exchanging services corresponding to a particular TID or AC. Furthermore, it can specify the TIDs or ACs that can be transmitted in the transmission direction within a link. As mentioned above, a default configuration can exist in the mapping between TIDs and links. Specifically, when no additional configuration exists in a multi-link setup, the multi-link device can exchange frames corresponding to TIDs on each link according to the default configuration. In this case, the default configuration could be exchanging all TIDs on any one 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.

[0136] When a link is mapped to a TID or AC, frames can be sent on that link based on the TID or AC mapped to the corresponding link. Specifically, when a link is mapped to a TID or AC, only frames corresponding to the TID or AC mapped to the corresponding link can be sent on that link. Therefore, when a link is mapped to a TID or AC, frames corresponding to TIDs or ACs not mapped to the corresponding link may not be sent on that link. When a link is mapped to a TID or AC, ACKs can also be sent based on the link mapped to the TID or AC. For example, a block ACK agreement can be determined based on the mapping between TIDs and links. In another embodiment, the mapping between TIDs and links can be determined based on a block ACK agreement. Specifically, a block ACK agreement can be set for TIDs mapped to a specific link.

[0137] exist Figure 10 In this embodiment, the AP multi-link device includes a first AP (AP1) and a second AP (AP2). The non-AP multi-link device includes a first station STA1 and a second station STA2. The first AP (AP1) and the first station STA1 are associated in the first link (link 1), and the second AP (AP2) and the second station STA2 are associated in the second link (link 2). All TIDs are mapped to the first link (link 1), and AC_VO or the TID corresponding to AC_VO is mapped to the second link (link 2). In this case, all TIDs are exchanged in the first link (link 1), and the TID corresponding to AC_VO is exchanged in the second link (link 2). Furthermore, data that does not correspond to AC_VO may not be allowed to be exchanged in the second link (link 2).

[0138] QoS can be guaranteed through the mapping between TIDs and links described above. Specifically, a relatively small number of stations or high-priority ACs or TIDs can be mapped to links with good channel conditions. Furthermore, through this mapping between TIDs and links, STAs can maintain power-saving states for longer periods.

[0139] Figure 11 A frame switching based on the reverse direction (RD) protocol according to an embodiment of the present invention is illustrated.

[0140] According to embodiments of the present invention, frames can be exchanged according to a reverse protocol. Specifically, a STA that is a transmit opportunity (TXOP) holder can be allowed to send a frame to a responder, and the responder can send a frame to a STA that is a TXOP holder. When a STA that is not a TXOP holder receives an RD grant (RDG) from a STA that is a TXOP holder, the STA that is not a TXOP holder can send a frame to the STA that is a TXOP holder within the corresponding TXOP. That is, the STA that receives the RDG can send a frame to the STA that is a TXOP holder without requiring additional contention-based channel access or backoff procedures. In this case, the station that sends the RDG can be called the RD initiator, and the station that receives the RDG can be called the RD responder. Furthermore, frame exchange according to the RD protocol can be called RD exchange or RD exchange sequence. HT stations, VHT stations, HE stations, EHT stations, DMG stations, and S1G (below 1 GHz) stations can support RD exchange.

[0141] A station can signal whether it can operate as an RD responder. Specifically, a station can signal whether it can operate as an RD responder using a subfield of the HT Extended Capabilities field of the HE Capabilities element. In this case, the subfield can be referred to as the RD responder field. In another specific embodiment, a station can signal whether it can operate as an RD responder using a 6GHz band capability element or a subfield of a 6GHz band capability element. If the station is signaled that it cannot operate as an RD responder, then RD licenses can be denied to that station.

[0142] A station can use at least one of the RDG / More PPDU subfield and the AC constraint subfield to signal information related to RD switching. In this case, the RDG / More PPDU subfield and the AC constraint subfield can be included in the HTC field. The HTC field can be a high throughput control field. Furthermore, a frame including the HTC field can be referred to as a +HTC frame. Additionally, the MPDU corresponding to a frame including the HTC field can be referred to as a +HTC MPDU. Furthermore, the CAS control subfield can include at least one of the RDG / More PPDU subfield and the AC constraint subfield.

[0143] RD exchanges can be performed as follows.

[0144] An RD initiator can send a PPDU that includes an RDG to an RD responder. In this case, the RD initiator can be a TXOP holder or a Service Cycle (SP) source. Whether an RDG is included can be signaled via the RDG / MorePPDU subfield. If the value of the RDG / MorePPDU subfield is 1, it indicates that the PPDU including the RDG / MorePPDU subfield includes the RDG. When the value of the RDG / MorePPDU subfield is 0, it indicates that the PPDU including the RDG / MorePPDU subfield does not include the RDG.

[0145] The station receiving the RDG can transmit the PPDU immediately after receiving the RDG. That is, the station receiving the RDG can transmit the PPDU without additional contention-based channel access. In this case, the interval between the PPDU including the RDG and the PPDU transmitted by the station receiving the RDG can be a short interframe space (SIFS) or a reduced interframe space (RIFS). In this specification, "immediately after" and "immediately" can represent a predetermined time interval. In this case, the predetermined time interval can be SIFS or RIFS.

[0146] In this embodiment, the station receiving the RDG can send a PPDU to the RD initiator. That is, the PPDU sent by the station receiving the RDG can include frames that the RD initiator expects to receive. Furthermore, the station receiving the RDG can send multiple PPDUs. One or more PPDUs sent by the station receiving the RDG after receiving a PPDU containing the RDG can be referred to as an RD response or an RD response burst. Furthermore, the station receiving the RDG and sending PPDUs (i.e., the station performing or sending an RD response) can be referred to as an RD responder. As described above, the RD responder can continuously send multiple PPDUs after receiving the RDG. The RD responder can send one PPDU and then immediately send another. In this case, the RD responder can signal in the frame contained in the PPDU whether to send an additional PPDU immediately after the PPDU containing that frame. That is, the RD responder can signal in the frame contained in the PPDU whether to send additional PPDUs at SIFS or RIFS intervals relative to the PPDU containing that frame. In this case, the RDG / More PPDU subfield described above can be used. Specifically, the RDG / More PPDU subfield sent by the RD initiator can indicate the RDG, and the RDG / More PPDU subfield sent by the RD responder can indicate whether an additional PPDU should be sent after the PPDU that includes the RDG / More PPDU subfield. Furthermore, an RD response may include at most one immediate BlockACK or ACK frame.

[0147] The RD initiator that receives an RD response can send an acknowledgment (ACK) to the RD responder. Specifically, the RD initiator can send an ACK to the RD responder immediately after receiving the RD response.

[0148] Multiple RD exchange sequences can be included in a single TXOP or SP. In this case, the RD initiators of the multiple RD exchange sequences can be the same, and the RD responders of the multiple RD exchange sequences can be different. In this embodiment, one RD responder can participate in multiple RD exchange sequences.

[0149] An RD responder can send PPDUs intended for multiple stations as an RD response. For example, when the RD responder is a VHTAP, the RD response may include a VHT MU PPDU. When the RD responder is a HE AP, the RD response may include a HE MU PPDU. If the RD responder is an EHT AP, the RD response may include an EHT MU PPDU. Furthermore, the RD responder can send an RD response that includes a trigger frame. In this case, the trigger frame can be limited to a frame that triggers the RD initiator's transmission. The trigger frame disclosed herein can indicate a frame that includes not only the trigger frame but also a triggered responsescheduling (TRS) field. A station receiving the trigger frame can respond to the PPDU including the trigger frame by sending a trigger-based (TB) PPDU. In this case, the interval between the PPDU including the trigger frame and the TB PPDU can be SIFS.

[0150] The AC or TID of frames that an RD responder can send in an RD response may be restricted. In this case, the RD initiator can signal to the RD responder whether the AC or TID of frames that can be sent in the RD response or RD response burst is restricted. Specifically, the RD initiator can use the AC constraint subfield to signal to the RD responder whether the AC or TID of frames that can be sent in the RD response is restricted. Furthermore, when the RD initiator acquires a TXOP via enhanced distributed channel access (EDCA), the AC or TID of frames that the RD responder can send in the RD response may be restricted. The RD initiator may not be allowed to request frames from the RD responder other than those used for ACK (acknowledgement). Therefore, the RD initiator may not request frames other than those used for ACK (acknowledgement) from the RD responder. In this case, frames used for ACK (acknowledgement) may include at least any one of ACK frames, compressed BlockAck frames, extended compressed Block frames, and multi-STA BlockAck frames.

[0151] When the RD responder signals that it will not send an additional PPDU, the RD initiator may send the PPDU immediately after the RD response. Specifically, when the RD initiator receives a frame from the RD responder that includes an HT control field, but the corresponding frame does not include an HT control field, the RD initiator may send the PPDU immediately after the RD response. In another specific embodiment, when the RD initiator receives a frame from the RD responder requesting an immediate response, the RD initiator may send the PPDU immediately after the RD response.

[0152] Furthermore, if the RD initiator does not receive an RD response to a PPDU including the RDG, the RD initiator may send a PPDU. Specifically, if the RD initiator does not receive a response to a PPDU including the RDG within a predetermined time, the RD initiator may send a PPDU after a predetermined time has elapsed since the PPDU including the RDG was sent. Specifically, the RD initiator may send the PPDU after a PIFS has elapsed since the PPDU including the RDG was sent. Additionally, the RD initiator may perform channel sensing before sending the PPDU and only send the PPDU when the channel is idle. This can be part of the RD initiator's error recovery operation.

[0153] RD responders can execute RD responses under the following conditions.

[0154] Furthermore, when an RD responder sends an RD response, the RD responder can send the RD response independently of the set network allocation vector (NAV).

[0155] Furthermore, the RD responder can execute an RD response only within the TXOP or SP obtained by the RD initiator. The RD responder can obtain the duration of the TXOP or SP from the MAC header of the frame included in the PPDU that includes the RDG. Specifically, the RD responder can obtain the duration of the TXOP or SP from the duration / ID field of the MAC header of the frame included in the PPDU that includes the RDG.

[0156] Furthermore, the frames that an RD responder can send as an RD response can be restricted. Specifically, the frames that an RD responder can send as an RD response can be limited to frames for ACK (acknowledgement), QoS data frames, QoS empty frames, management frames, and basic trigger frames. In this case, frames for ACK (acknowledgement) can include at least any one of ACK frames, compressed BlockAck frames, extended compressed Block frames, and multi-STA BlockAck frames.

[0157] Furthermore, the intended receiver of at least one frame included in the RD response can be limited to the RD initiator. The intended receiver of the frame can be indicated by a MAC address. Specifically, the station corresponding to the MAC address indicated by the Address 1 field of the frame can be the intended receiver of the frame. In another specific embodiment, the station that triggers the transmission by the trigger frame can be the intended receiver of the trigger frame.

[0158] Furthermore, when an RD responder sends an RD response, it may send only a PPDU with a width equal to or less than the channel width of the PPDU including the RDG. In this case, the RD responder can determine the channel width of the PPDU including the RDG by the value of CH_BANDWIDTH of RXVECTOR obtained when receiving the PPDU including the RDG.

[0159] When an RD responder requests an immediate block ACK response via a PPDU that includes an RDG, the RD responder may include a BlockAck frame in the first PPDU of the RD response. As described above, when the RD responder sends multiple PPDUs as an RD response, the RD responder may signal to send additional PPDUs in PPDUs that are not the last PPDU of the RD response. Specifically, the RD responder may set the value of the RDG / MorePPDU field of the PPDU that is not the last PPDU of the RD response to indicate that additional PPDUs should be sent. Furthermore, the RD responder may set the value of the RDG / MorePPDU field of the PPDU that is not the last PPDU of the RD response to indicate that additional PPDUs should not be sent. In this case, if the value of the RDG / MorePPDU field is 1, it indicates that additional PPDUs should be sent. Furthermore, if the value of the RDG / MorePPDU field is 0, it indicates that additional PPDUs should not be sent. Additionally, the RD responder may not be permitted to send additional PPDUs after sending a PPDU that includes a frame requesting an immediate response. Therefore, the RD responder may signal not to send additional PPDUs when sending a PPDU that includes a frame requesting a response. Furthermore, after the RD responder signals that it will not send an additional PPDU, the RD responder may choose not to send an additional PPDU as an RD response.

[0160] When an RD responder sends a trigger frame, the RD responder can set fields in the trigger frame so that channel sensing is not required in the response to the trigger frame. Specifically, the RD responder can set the CS required field of the trigger frame to 1. In this case, the trigger frame can be a basic trigger frame.

[0161] As described above, the TID or AC of frames included in a PPDU sent by the RD responder as an RD response can be restricted. When the RD initiator signals to the RD responder that the AC or TID of frames that can be sent is restricted, the RD responder may include frames corresponding to the same AC as the frame that includes the RDG in its PPDU. Specifically, when the RD initiator sets the RDG / More PPDU subfield to 1 and the AC constraint subfield to 1, the RD responder may include frames corresponding to the same AC as the frame that includes the RDG in its PPDU. Furthermore, when the RD initiator signals to the RD responder that the AC or TID of frames that can be sent is restricted, the RD responder may be configured such that the preferred AC subfield of the triggering frame included in the RD response indicates the same AC as the frame that includes the RDG. The preferred AC subfield may indicate a recommendation for the AC of the MPDU included in the PPDU sent as a response to a frame that includes the preferred AC subfield. Specifically, the preferred AC subfield can indicate the AC with the lowest priority among the ACs of the MPDU included in the PPDU that is recommended to be sent as a response to a frame including the preferred AC subfield. As mentioned above, the preferred AC subfield can be included in the trigger frame. Specifically, the preferred AC subfield can be included in the base trigger frame.

[0162] exist Figure 11 In this embodiment, the first station (STA A) is the RD initiator. Furthermore, the second station (STA B) and the third station (STA C) can be RD responders. Figure 11 In one embodiment, eight PPDU exchanges are performed during TXOP.

[0163] In the first PPDU exchange (a), the first station (STA A) sends a PPDU that includes a QoS data frame for which the second station (STA B) is the desired receiver. In this case, the Ack policy field of the QoS data frame, which indicates the response rules for the data frame, can be set to an implicit BlockAckReq indicating a request for an immediate response using a BlockAck frame. Furthermore, the RDG / MorePPDU subfields of the two QoS data frames included in the PPDU represent RDG. Additionally, the duration / ID field of the QoS data frame indicates the duration of the remaining TXOP.

[0164] In the second PPDU exchange (b), the second station (STA B) sends a PPDU to the first station (STA A) that includes a BlockAck frame as a +HTC frame. The value of the RDG / More PPDU field of the BlockAck frame is set to 1, and a signal is given to send an additional PPDU after the transmission of the PPDU including the BlockAck frame.

[0165] In the third PPDU exchange (c), the second station (STA B) sends a PPDU including the QoS data frame to the first station (STA A). In this case, the second station (STA B) sets the RDG / More PPDU subfield value of the QoS data frame to 0 and signals that no additional PPDU will be sent after the PPDU including the BlockAck frame.

[0166] In the fourth PPDU exchange (d), the first station (STA A) can regain control of the TXOP. STA A1 sends a PPDU including a BlockAck frame for the second station (STA B). In this case, the BlockAck frame may include ACKs for QoS data frames sent in the second and third PPDU exchanges.

[0167] In the fifth PPDU exchange (e), the first station (STA A) sends a PPDU that includes a QoS data frame for which the third station (STA C) is the intended receiver. In this case, the Ack policy field of the QoS data frame can be set to an implicit BlockAck request. Furthermore, the first station (STA A) signals the RDG by setting the RDG / MorePPDU subfield of the two QoS data frames included in the PPDU to 1. Additionally, the duration / ID field of the QoS data frame indicates the duration of the remaining TXOP.

[0168] In the sixth PPDU exchange (f), the third station (STA C) sends a PPDU to the first station (STA A) that includes a BlockAck frame as a +HTC frame and a QoS data frame. In this case, the third station (STA C) sets the Ack policy field of the QoS data frame to an implicit BlockAck request. Furthermore, the third station (STA C) sets the RDG / More PPDU subfield value of the QoS data frame to 0 to signal that no additional PPDU will be sent after the PPDU including the BlockAck frame.

[0169] In the seventh PPDU exchange (g), the first station (STA A) can regain control of the TXOP. The first station (STA A) sends a PPDU that includes a BlockAck frame for the third station (STA C). In this case, the BlockAck frame may include an ACK for the QoS data frame sent in the sixth PPDU exchange. The first station (STA A) signals the RDG by setting the RDG / More PPDU subfield of the BlockAck frame included in the PPDU to 1.

[0170] In the eighth PPDU exchange (h), the third station (STA C) sends a PPDU containing two QoS data frames as a +HTC frame to the first station (STA A). In this case, the third station (STA C) sets the Ack policy field of the QoS data frame to an implicit BlockAck request. Furthermore, the third station (STA C) sets the RDG / More PPDU subfield value of the QoS data frame to 0 to signal that no additional PPDU will be sent after the PPDU containing the BlockAck frame.

[0171] In the ninth PPDU exchange (i), the first station (STA A) sends a PPDU including a BlockAck frame to the third station (STA C), the BlockAck frame including an ACK for the QoS data frame sent in the eighth PPDU exchange.

[0172] As mentioned above, in the RD protocol, the AC or TID of the frame included in the PPDU sent by the RD responder as an RD response may be limited. This may be because the TXOP holder obtains the TXOP using channel access parameters corresponding to a specific AC, taking into account the balance with other stations. (See also...) Figure 12 Describe in detail the AC or TID constraints of the frames included in the PPDU sent as an RD response. For ease of description, the AC or TID constraints of the frames included in the PPDU sent as an RD response are referred to as AC constraints.

[0173] Figure 12 AC restriction signaling according to an embodiment of the present invention is shown.

[0174] AC limiting signaling can indicate that the TID of a data frame included in a PPDU of an RDG response is unrestricted. That is, AC limiting signaling can signal that a PPDU of an RDG response can include data frames with any TID. Furthermore, AC limiting signaling can indicate that the AC or TID of a frame included in a PPDU of an RDG response can be limited. Specifically, AC limiting signaling can limit the AC or TID of a frame included in a PPDU of an RDG response to the AC or TID value indicated by the RD initiator. In another specific embodiment, AC limiting signaling can indicate that the AC or TID of a data frame included in a PPDU of an RDG response is limited to a value set based on the TID or AC of a frame received from the RD initiator. For example, AC limiting signaling can indicate that the AC or TID of a data frame included in a PPDU of an RDG response is limited to the TID or AC of a frame received from the RD initiator. Furthermore, AC limiting signaling can indicate that the AC or TID of a frame included in a PPDU of an RDG response is limited to a TID or AC with a priority equal to or higher than the priority of the TID or AC of a frame received from the RD initiator. In this embodiment, a frame received from the RD initiator may represent the last frame received from the RD initiator. In another specific embodiment, when the RD responder receives multiple frames from the RD initiator, the frame received from the RD initiator may represent the TID or AC with the lowest priority among the frames received from the RD initiator.

[0175] The RD responder can treat the AC of the management frame as a predetermined value. In this case, the predetermined value can be AC_VO. Furthermore, the RD responder can determine the AC of the BlockAckReq frame based on the TID field of the BlockAckReq frame, and determine the AC of the BlockAck frame based on the indication of the TID field of the BlockAck frame. Specifically, the RD responder can determine the AC of the BlockAckReq frame as the AC of the TID indicated by the TID field of the BlockAckReq frame, and determine the AC of the BlockAck frame as the AC of the TID indicated by the TID field of the BlockAck frame. In this case, the TID fields of the BlockAck frame and the BlockAckReq frame can indicate the TID of the transmitted Ack. Additionally, when the RD initiator sends a frame whose AC cannot be determined, the RD initiator may not be allowed to set the RDG of the corresponding frame. Specifically, when the RD initiator sends a frame whose AC cannot be determined, the RD initiator may not be allowed to set the RDG / More PPDU field of the corresponding frame to 1.

[0176] AC restriction signaling can be indicated by the aforementioned AC constraint subfield. Specifically, when the value of the AC constraint subfield is 0, it indicates that the TID of the data frame included in the PPDU of the RDG response is not restricted. Furthermore, when the value of the AC constraint subfield is 1, it indicates that the TID or AC of the frame included in the PPDU of the RDG response is restricted.

[0177] exist Figure 12 In this embodiment, the RD initiator sends a QoS data frame as AC_BE to the RD responder via a PPDU that includes the RDG. In this case, the RD initiator sets the value of the AC constraint field to 1, thereby indicating that the TID or AC of the data frame included in the RD response PPDU is restricted. Since the TID or AC of the data frame included in the RD response PPDU is restricted, the RD responder includes the QoS data frame corresponding to AC_BE in the RD response PPDU.

[0178] Figure 13 The frame format and the format of the signaling field of the frame are shown according to an embodiment of the present invention.

[0179] Figure 13 (a) illustrates the format of a MAC frame. A MAC frame may include a MAC header, a frame body, and an FCS. The MAC header may include at least one of the RDG / More PPDU subfields and the AC constraint subfield.

[0180] Specifically, the MAC header may include a frame control field, a duration / ID field, a MAC address field, a sequence control field, a QoS control field, and an HT control field. The frame control field may include a type subfield and a subtype subfield. Each of the type subfield and subtype subfield can indicate the type and subtype of the frame. Additionally, the frame control field may include a +HTC subfield, which can indicate whether the frame including the frame control field includes an HT control field. The duration / ID field indicates the duration. If the frame including the duration / ID field is not a PS-Poll frame, the duration / ID field indicates the duration. Furthermore, the station receiving the MAC frame can set the NAV based on the duration indicated by the duration / ID field. The duration / ID field can indicate an ID, such as an AID. If the MAC frame including the duration / ID field is a PS-Poll frame, the duration / ID field can indicate the ID.

[0181] In addition, the MAC address field may include one or more address fields. The address field indicates the MAC address. Furthermore, the address field may include at least any one of the following: a basic service set identifier (BSSID) field, a source address (SA) field, a destination address (DA) field, a transmitting STA address or transmitter address (TA) field, and a receiving STA address or receiver address (RA) field. Additionally, the sequence control field may indicate the fragment number or sequence number corresponding to the MAC frame including the sequence control field. Furthermore, the QoS control field may indicate at least any one of the following: the TID of the MAC frame including the QoS control field, the Ack policy corresponding to the MAC frame including the QoS control field, the TXOP limit, the buffer status of the station sending the MAC frame including the QoS control field, and the queue size of the station sending the MAC frame including the QoS control field. Additionally, the QoS control field may include at least one of the RDG / More PPDU subfields and AC constraint subfields described above. For example, the QoS control field included in the DMG PPDU may include the RDG / More PPDU subfields and AC constraint subfields as described above.

[0182] The HT control field may include at least one of the RDG / More PPDU subfields and the AC constraint subfield. The HT control field may consist of 4 octets (i.e., 32 bits).

[0183] The MAC header and the fields included in the MAC header can have a predetermined length.

[0184] The frame body field includes the contents of the MAC frame. For example, the frame body field may include information corresponding to the frame type and subtype.

[0185] The FCS field indicates the frame check sequence (FCS) of the MAC frame, which includes the FCS field. The value of the FCS field can be obtained based on the values ​​of the MAC header and frame body fields. The station receiving the MCA frame can determine whether the MAC frame was successfully received based on the value of the FCS field.

[0186] Figure 13 (b) shows the format of the HT control field. The HT control field may include at least one of the AC constraint subfield and the RDG / more PPDU subfield.

[0187] For example, an HT control field can consist of 32 bits (B0 to B31). In this case, B30 and B31 can be the AC constraint subfield and the RDG / More PPDU subfield, respectively. The format of the HT control field can vary depending on the format of the PPDU that includes the HT control field. The aforementioned HT control field can be an HT variant included in an HT PPDU or a VHT variant included in a VHT PPDU. Furthermore, the format of the HT control field can include an HE variant included in an HE PPDU or an EHT variant included in an EHT PPDU. In this case, the HE variant can represent a variant of the HT control field included in PPDUs introduced in versions of the 802.11ax standard and later. The HT control field can include signaling indicating which variant the HT control field is. For example, some bits of the HT control field can indicate which variant the HT control field is. When the value of B0 is 0, B0 can indicate that the HT control field is an HT variant. When the value of B0 is 1, B0 can indicate that the HT control field is a VHT variant, HE variant, or EHT variant. When the value of B0 is 1 and the value of B1 is 0, B0 and B1 can indicate that the HT control field is a VHT variant. When the value of B0 is 1 and the value of B1 is 1, B0 and B1 can indicate that the HT control field is an HE variant or an EHT variant. In another specific embodiment, when the value of B0 is 1 and the value of B1 is 1, B0 and B1 can indicate that the HT control field is an HE variant, an EHT variant, or a variant of the HT control field included in a PPDU introduced after the 802.11be standard. Furthermore, when the HT control field is an HE variant, an EHT variant, or a variant of the HT control field included in a PPDU introduced after the 802.11be standard, the HT control field can include an A (aggregate control) - control subfield. For example, HT control fields B2 to B31 can be A-control subfields. The A-control subfield can include control information.

[0188] Figure 13 (c) shows Figure 13(b) The A-control subfield. The A-control subfield may include a control list subfield and a padding subfield. The control list subfield may include one or more control information. The control list subfield may include one or more control subfields. Furthermore, the A-control subfield may or may not include a padding subfield. For example, the remainder of a predetermined length of the A-control subfield, excluding the control list subfield, may be a padding subfield. In a specific embodiment, the padding subfield may be set to a predetermined value. Alternatively, the padding subfield may begin with a predetermined value.

[0189] Figure 13 (d) shows Figure 13 The format of the control subfield of (c). The control subfield may include a control ID subfield and a control information subfield.

[0190] The control ID subfield can indicate what content is included in the control information subfield or what control information is included in the control subfield that includes the control ID subfield. Furthermore, the station can determine the length of the control information subfield based on the value of the control ID subfield. The length of the control ID subfield can be 4 bits. The information that the control subfield can include may include triggered response scheduling (TRS) control as described above. The control subfield can include the TRS, which is information used to trigger the transmission of the station receiving the control subfield. The control ID value corresponding to the TRS can be 0. In addition, the control subfield can include information about the operating mode (OM). The control ID value corresponding to the OM can be 1. Furthermore, the control subfield can include information about link adaptation. The control ID value corresponding to the link adaptation information can be 2. Furthermore, the control subfield can include information about buffers. The information about buffers can be a buffer status report (BSR). The control ID value corresponding to the BSR can be 3. Furthermore, the control subfield can include information about uplink power headroom (UL). Information regarding uplink power headroom can indicate how much remaining capacity is available in the transmittable power or a value used for power pre-correction. The control ID value corresponding to the uplink power headroom information can be 4. Additionally, the control subfield can include signaling indicating the status of a subchannel. Signaling indicating the subchannel status can include a bandwidth query report (BQR). The control ID value corresponding to the BQR can be 5. For example, a BQR can indicate whether a subchannel is available. Furthermore, the control subfield can include information about command and status (CAS). The control ID value corresponding to the CAS can be 6.

[0191] Figure 13(e) illustrates the format of the control information subfield when the control subfield includes CAS. According to an embodiment of the invention, the A-control subfield may include an AC constraint subfield and an RDG / More PPDU subfield. Specifically, when the A-control subfield includes CAS, the control information subfield corresponding to CAS may include an AC constraint subfield and an RDG / More PPDU subfield. For example, the first bit and the second bit of the control information subfield corresponding to CAS may be the AC constraint subfield and the RDG / More PPDU subfield, respectively. Furthermore, CAS may include a PSRT PPDU subfield. The PSRT subfield may indicate whether the PPDU including the PSRT subfield is a PSRT (Parameterized Spatial Reuse Transmission) PPDU. Furthermore, a PSRT PPDU is a PPDU transmitted via a parameterized spatial reuse (PSR) opportunity. Additionally, when the control subfield includes CAS, the control information subfield may include a Reserved field.

[0192] exist Figure 13 The AC constraint subfield and RDG / more PPDU subfield described in the figure can be the AC constraint subfield and RDG / more PPDU subfield described in the previous figure.

[0193] Even when performing RD switching, the aforementioned TID-to-link mapping can still be applied. In this case, AC restrictions can also be applied to RD switching. Therefore, when performing RD switching on a link with applied TID-to-link mapping, the range of frames that the RD responder can send in the RD response may be problematic. This will refer to... Figures 14 to 20 Describe it.

[0194] Figure 14 An embodiment of the invention is shown, in which RD switching without AC restrictions is performed in a link with TID-to-link mapping.

[0195] When RD switching is performed on a link with TID-to-link mapping and no AC restrictions are applied in the RD switching, the RD responder can perform an RD response based on the TID or AC mapped to the link. Specifically, when RD switching is performed on a link with TID-to-link mapping and no AC restrictions are applied in the RD switching, the RD responder can send frames in the RD response corresponding to either the TID or AC mapped to the link. In this case, the RD responder can select any AC or TID from the TID and AC mapped to the link and can send data frames corresponding to the AC or TID selected in the RD response. Specifically, the RD responder can include data frames corresponding to the TID mapped to the link in the PPDU sent as a response to a PPDU including the RDG, and can exclude data frames corresponding to TIDs not mapped to the link from the sent PPDU. That is, even without AC restrictions, the RD responder may not be allowed to send frames corresponding to TIDs or ACs that are not mapped to the link.

[0196] In another specific embodiment, when RD switching is performed on a link with TID-to-link mapping and no AC restrictions are applied in the RD switching, the RD responder can send a data frame in the RD response corresponding to a TID or AC with a priority equal to or higher than the priority of the TID or AC mapped to the link. Specifically, when RD switching is performed on a link with TID-to-link mapping and no AC restrictions are applied in the RD switching, the RD responder can send a data frame in the RD response corresponding to a TID or AC with a priority higher than the lowest priority among the TIDs or ACs mapped to the link. Therefore, when RD switching is performed on a link with TID-to-link mapping and no AC restrictions are applied in the RD switching, the RD responder may not be able to send a data frame in the RD response corresponding to the lowest priority among the TIDs or ACs mapped to the link.

[0197] In the above embodiments, the TID-to-link mapping can represent the TID-to-link mapping applied in the transmission of the RD responder. This is because the TID-to-link mapping applied to the RD initiator is not applied to the RD responder. Furthermore, embodiments of the present invention can be applied to situations where the RD responder performs transmissions to multiple stations in the RD response.

[0198] exist Figure 14In this embodiment, the AP multi-link device includes a first AP (AP1) and a second AP (AP2). Additionally, the non-AP multi-link device includes a first station STA1 and a second station STA2. The first AP (AP1) and the first station STA1 are associated in the first link (Link 1), and the second AP (AP2) and the second station STA2 are associated in the second link (Link 2). All TIDs are mapped to the first link (Link 1). In the second link (Link 2), the second AP (AP2) can send all TIDs. However, in the second link (Link 2), when the second station STA2 sends a data frame, the second station STA2 can send data frames corresponding to AC_VO and AC_VI in the second link (Link 2) according to the TID-to-link mapping.

[0199] In the second link (link 2), the second AP (AP2) sends an RDG to the second station. In this case, the second AP (AP2) sets the value of the AC constraint subfield to 0 to signal that the AC constraint is not applied. The second station STA2 sends a data frame corresponding to AC_VI or AC_VO in the RD response. Furthermore, the second station STA2 cannot send data frames that do not correspond to AC_VI or AC_VO in the RD response.

[0200] Figure 15 Another embodiment of the invention is shown, in which RD switching without AC restrictions is performed in a link with TID-to-link mapping.

[0201] When RD switching is performed on a link with TID-to-link mapping and no AC restrictions are applied in the RD switching, the RD responder can perform an RD response regardless of the TID-to-link mapping. Specifically, when RD switching is performed on a link with TID-to-link mapping and no AC restrictions are applied in the RD switching, the RD responder can send a data frame corresponding to any TID in the RD response, regardless of the TID-to-link mapping. In a specific embodiment, when RD switching is performed on a link with TID-to-link mapping and no AC restrictions are applied in the RD switching, the RD responder can send a data frame corresponding to an AC or TID that is not mapped to the link in the RD response.

[0202] In the above embodiments, the TID-to-link mapping can represent the TID-to-link mapping applied in the transmission of the RD responder. This is because the TID-to-link mapping applied to the RD initiator is not applied to the RD responder. Furthermore, embodiments of the present invention can be applied to situations where the RD responder performs transmissions to multiple stations in the RD response.

[0203] exist Figure 15 In this embodiment, the AP multi-link device includes a first AP (AP1) and a second AP (AP2). Additionally, the non-AP multi-link device includes a first station STA1 and a second station STA2. The first AP (AP1) and the first station STA1 are associated in the first link (Link 1), and the second AP (AP2) and the second station STA2 are associated in the second link (Link 2). All TIDs are mapped to the first link (Link 1). In the second link (Link 2), the second AP (AP2) can transmit all TIDs; however, when the second station STA2 transmits data frames in the second link (Link 2) according to the TID-to-link mapping, the second station STA2 can transmit data frames corresponding to AC_VO and AC_VI in the second link (Link 2).

[0204] In the second link (Link 2), the second AP (AP2) sends an RDG to the second station. In this case, the second AP (AP2) sets the value of the AC constraint subfield to 0 to signal that AC restrictions are not applied. In the RD response, the second station STA2 can send a data frame corresponding to any TID, regardless of the TID-to-link mapping applied to the second link (Link 2). Therefore, the second station STA2 sends a QoS data frame in the RD response corresponding to an AC_BE that is not mapped to the second link (Link 2).

[0205] Figure 16 Another embodiment of the invention is shown, in which no AC limit is set when RD switching is performed in a link with TID-to-link mapping applied.

[0206] If the TID or AC of a frame sent by the RD initiator via a PPDU including the RDG does not map to the link used by the RD responder in the RD response, the RD initiator may not be allowed to apply the AC restriction. That is, when the TID or AC of a frame sent by the RD initiator via a PPDU including the RDG does not map to the link used by the RD responder in the RD response, the RD initiator may not apply the AC restriction. In this case, the RD initiator can signal that it is not applying the AC restriction.

[0207] In another specific embodiment, the RD initiator may not be allowed to apply the AC restriction when a TID or AC with a higher priority than the TID or AC of a frame sent by the RD initiator via a PPDU including the RDG is not mapped to the link used by the RD responder in the RD response. That is, the RD initiator may not apply the AC restriction when a TID or AC with a higher priority than the TID or AC of a frame sent by the RD initiator via a PPDU including the RDG is not mapped to the link used by the RD responder in the RD response. In this case, the RD initiator can signal that the AC restriction is not applied.

[0208] In the above embodiments, the TID or AC of a frame sent by the RD initiator via a PPDU including the RDG can be the TID or AC with the lowest priority among the TIDs or ACs of frames sent by the RD initiator via a PPDU including the RDG. In another specific embodiment, the TID or AC of a frame sent by the RD initiator via a PPDU including the RDG can be the TID or AC with the lowest priority among the TIDs or ACs of frames received by the RD responder from a PPDU including the RDG. In another specific embodiment, the TID or AC of a frame sent by the RD initiator via a PPDU including the RDG can be the TID or AC of the last frame received by the RD initiator via a PPDU including the RDG. In another specific embodiment, the TID or AC of a frame sent by the RD initiator via a PPDU including the RDG can be the TID or AC of the last frame received by the RD responder from a PPDU including the RDG.

[0209] In the above embodiments, the TID-to-link mapping can represent the TID-to-link mapping applied in the transmission of the RD responder. This is because the TID-to-link mapping applied to the RD initiator is not applied to the RD responder. Furthermore, embodiments of the present invention can be applied to situations where the RD responder performs transmissions to multiple stations in the RD response.

[0210] exist Figure 16In this embodiment, the AP multi-link device includes a first AP (AP1) and a second AP (AP2). Additionally, the non-AP multi-link device includes a first station STA1 and a second station STA2. The first AP (AP1) and the first station STA1 are associated in the first link (Link 1), and the second AP (AP2) and the second station STA2 are associated in the second link (Link 1). All TIDs are mapped to the first link (Link 1). In the second link (Link 2), the second AP (AP2) can transmit all TIDs. However, in the second link (Link 2), when the second station STA2 transmits a data frame, according to the TID-to-link mapping, the second station STA2 can transmit frames corresponding to AC_VO and AC_VI in the second link (Link 2).

[0211] In the second link (link 2), the second AP (AP2) sends an RDG to the second station. In this case, the second AP (AP2) sets the value of the AC constraint subfield to 0 to signal that AC restrictions are not applied. This is because the second AP (AP2) sends a QoS data frame corresponding to AC_BE via a PPDU that includes the RDG, and AC_B is not mapped to the second link (link 2) sent by the second station STA2. The second station STA2 can refer to... Figure 14 and Figure 15 Any of the described embodiments is used to perform the RD response.

[0212] Figure 17 This illustrates RD switching when AC restrictions are applied in a link with TID-to-link mapping, according to another embodiment of the invention.

[0213] When the RD initiator signals that the AC is restricted in the RD response, the RD responder may be permitted to send frames in the RD response corresponding to a TID or AC not mapped to the link executing the RD response. In this case, the RD responder may determine the TID or AC of the frame sent in the RD response based on the TID or AC of the frame received via the PPDU including the RDG. Specifically, the RD responder may determine the TID or AC of the frame sent in the RD response to be the same as the TID or AC of the frame received via the PPDU including the RDG. In another specific embodiment, the RD responder may determine the TID or AC of the frame sent in the RD response to be an AC or TID with a priority equal to or higher than the priority of the TID or AC of the frame received via the PPDU including the RDG. The TID or AC of the frame received via the PPDU including the RDG may be the TID or AC of the last frame received via the PPDU including the RDG. Furthermore, as described in the embodiments above, exception transmissions for TID-to-link mapping may only be permitted for RD exchanges where the AC restriction is signaled.

[0214] In the above embodiments, the TID-to-link mapping can represent the TID-to-link mapping applied in the transmission of the RD responder. This is because the TID-to-link mapping applied to the RD initiator is not applied to the RD responder. Furthermore, embodiments of the present invention can be applied to situations where the RD responder performs transmissions to multiple stations in the RD response.

[0215] exist Figure 17 In this embodiment, the AP multi-link device includes a first AP (AP1) and a second AP (AP2). Additionally, the non-AP multi-link device includes a first STA1 and a second STA2. The first AP (AP1) and the first STA1 are associated in the first link (Link 1), and the second AP (AP2) and the second STA2 are associated in the second link (Link 1). All TIDs are mapped to the first link (Link 1). Although the second AP (AP2) in the second link (Link 2) can transmit all TIDs, according to the TID-to-link mapping, the second STA2 can only transmit frames corresponding to AC_VO and AC_VI in the second link (Link 2).

[0216] In the second link (Link 2), the second AP (AP2) sends an RDG to the second station. In this case, the second AP (AP2) sets the value of the AC constraint subfield to 1 to signal that the AC restriction is applied. Furthermore, the second AP (AP2) sends a QoS data frame corresponding to AC_BE via a PPDU including the RDG. Although AC_BE is not mapped to the second link (Link 2), the second station STA2 sends a frame corresponding to AC_BE in its RD response.

[0217] Figure 18 This illustrates RD switching when AC restrictions are applied in a link with TID-to-link mapping, according to another embodiment of the invention.

[0218] In another implementation, when the RD initiator signals that the AC is limited in the RD response and the TID-to-link mapping is applied to the link executing the RD response, the RD responder can send any TID in the RD response. That is, when the RD initiator signals that the AC is limited in the RD response and the TID-to-link mapping is applied to the link executing the RD response, the RD responder can send any TID in the RD response. Figure 15 The described embodiment sends an RD response.

[0219] exist Figure 18 In this embodiment, the AP multi-link device includes a first AP (AP1) and a second AP (AP2). Additionally, the non-AP multi-link device includes a first station STA1 and a second station STA2. The first AP (AP1) and the first station STA1 are associated in the first link (Link 1), and the second AP (AP2) and the second station STA2 are associated in the second link (Link 1). All TIDs are mapped to the first link (Link 1). In the second link (Link 2), the second AP (AP2) can send all TIDs. However, in the second link (Link 2), when the second station STA2 sends a data frame, the second station STA2 can send data frames corresponding to AC_VO and AC_VI in the second link (Link 2) according to the TID-to-link mapping.

[0220] In the second link (link 2), the second AP (AP2) sends an RDG to the second station. In this case, the second AP (AP2) sets the value of the AC constraint subfield to 1 to signal that the AC constraint is applied. In the RD response, the second station STA2 can send a data frame corresponding to any TID, including TIDs that do not correspond to the AC or TID mapped to the second link.

[0221] When RD switching is performed on a link with TID-to-link mapping and AC restrictions are applied in the RD switching, the RD responder can perform an RD response based on the TID or AC mapped to the link. Specifically, when RD switching is performed on a link with TID-to-link mapping and AC restrictions are applied in the RD switching, the RD responder can send a data frame corresponding to an AC or TID with a priority equal to or higher than the AC or TID of the frame received from the RD initiator, and corresponding to any of the TID or AC of the link mapped to the RD response. For ease of description, the PPDU sent in response to a PPDU including an RDG is called an RD response PPDU. Specifically, when the RD responder sends a data frame in the RD response, the RD responder may not include in the RD response PPDU a data frame corresponding to a TID or AC with a priority lower than the TID or AC of the frame received from the RD initiator, or a TID or AC not mapped to the link. In this case, the RD responder may include in the PPDU sent as a response to the RDG a data frame corresponding to a TID or AC with a priority equal to or higher than the TID or AC of the frame received from the RD initiator, and corresponding to the TID or AC mapped to the link, and include it in the RD response PPDU.

[0222] A frame received from the RD initiator can represent the last frame received by the RD responder from the RD initiator. In another specific embodiment, when the RD responder receives multiple frames from the RD initiator, the frame received from the RD initiator can represent the TID or AC with the lowest priority among the frames received from the RD initiator. In this case, the multiple frames can be multiple frames included in the last PPDU received from the RD initiator.

[0223] Figure 19 An embodiment of the present invention illustrates how an RD initiator uses signals to notify information about AC restrictions used in an RD response.

[0224] The RD initiator can signal information about the AC restrictions applied in the RD exchange. For ease of description, this signaling is called AC restriction information signaling. The RD responder can determine the AC or TID of the frame to be sent in the RD response based on the AC restriction information signaling. Information about the AC restrictions applied in the RD exchange can be referenced... Figures 11 to 18 Information used in the described embodiments. For example, information regarding AC limits may indicate references. Figures 11 to 18The described embodiment describes an AC limiting method. For example, AC limiting information signaling can indicate whether a TID-to-link mapping should be applied in an RD response. If the AC limiting information signaling is a predetermined first value and the AC constraint subfield indicates that the TID or AC is not limited, the RD responder can send an RD response regardless of the TID-to-link mapping. If the AC limiting information signaling is a predetermined second value and the AC constraint subfield indicates that the TID or AC is not limited, the RD responder can send an RD response based on the TID-to-link mapping. Specifically, when the AC limiting information signaling is a predetermined second value and the AC constraint subfield indicates that the TID or AC is not limited, the RD responder can perform the RD response using only the TID or AC mapped to the link performing the RD response, based on the TID-to-link mapping.

[0225] If the AC constraint subfield indicates that the TID or AC is restricted, the RD responder can determine whether to perform an RD response by applying the TID-to-link mapping based on the AC constraint information signaling.

[0226] AC restriction information signaling can be included in the A-control subfield. In another specific embodiment, AC restriction information signaling can be included in the CAS. Figure 19 The control information subfield of CAS according to an embodiment of the present invention is shown. In this case, the control information subfield includes AC restriction information signaling (i.e., AC indication subfield). In another specific embodiment, the AC restriction information signaling may be included in the control information subfield. Figure 13 (e) describes the reserved fields of the control information field.

[0227] Figure 20 An embodiment of the invention is shown in which RD switching is performed when a PPDU that has been synchronized upon completion of transmission is sent in multiple links.

[0228] A multi-link device can synchronize PPDUs transmitted across multiple links. Specifically, a multi-link device can synchronize the ends of PPDUs transmitted across multiple links. In another embodiment, a multi-link device can synchronize the beginnings of PPDUs transmitted across multiple links. This operation can be applied when the transmission / reception capability of a multi-link device receiving PPDUs on at least any of the multiple links is limited. This operation can also be applied when a multi-link device receiving PPDUs on at least any of the multiple links cannot simultaneously receive and transmit PPDUs. A multi-link device that can perform reception on one link while performing transmission on another is called a simultaneous transmit and receive (STR) multi-link device. A multi-link device that can perform reception on one link but cannot perform transmission on another is called a non-STR multi-link device. Therefore, a multi-link device that performs transmission for a non-STR multi-link device across multiple links can transmit synchronized PPDUs.

[0229] RD switching can be configured based on whether or not to send synchronous PPDUs.

[0230] When transmitting synchronized PPDUs across multiple links, a multi-link device may transmit RDGs only on any one of the links. In this case, the RD response may be transmitted only on the link that transmitted the RDG. For example, when the multi-link device transmits synchronized PPDUs on a first link and a second link, the multi-link device may include the RDG in the PPDU transmitted on the first link. In this case, a first PPDU may be transmitted as a response to a synchronized PPDU on the first link, and a second PPDU may be transmitted as a response to a synchronized PPDU on the second link. A first frame may be transmitted in the first PPDU, and a second frame may be transmitted in the second PPDU, and the length of the first frame may be greater than the length of the second frame. For example, the first frame may include a data frame, and the second frame may include an ACK. In this case, the second PPDU may include padding to synchronize the first and second PPDUs. Therefore, this may increase transmission inefficiency.

[0231] If a synchronous PPDU is transmitted across multiple links, the RDG can be transmitted on all links or not on any of them. When a multi-link device transmits synchronous PPDUs across multiple links, it can set the values ​​of the RDG / More PPDU subfields transmitted on all links to the same value. Alternatively, it can set all the values ​​of the RDG / More PPDU subfields transmitted on all links to 1 or all to 0. This improves transmission efficiency.

[0232] In another specific embodiment, regardless of whether a synchronous PPDU is sent, the RDG can be sent on multiple links, or the RDG can be not sent on any of the multiple links.

[0233] In another embodiment, if the multi-link device receiving PPDUs on multiple links is a non-STR multi-link device, then RDG may be sent on all links or not sent on any of them. If the multi-link device receiving PPDUs on multiple links is a non-STR multi-link device, then the multi-link device may set the value of the RDG / MorePPDU subfield sent on multiple links to the same value. If the multi-link device receiving PPDUs on multiple links is a non-STR multi-link device, then the multi-link device may set the value of all RDG / MorePPDU subfields sent on multiple links to 1 or all to 0. This is because when RD exchange with a non-STR multi-link device is performed only on any one link, transmission on other links may be restricted.

[0234] exist Figure 20 In this embodiment, the AP multi-link device includes a first AP (AP1) and a second AP (AP2). The non-AP multi-link device includes a first station STA1 and a second station STA2. The first AP (AP1) and the first station STA1 are associated in the first link (link 1), and the second AP (AP2) and the second station STA2 are associated in the second link (link 2). In this case, the first AP (AP1) and the second AP (AP2) send synchronized PPDUs and set the values ​​of the RDG / MorePPDU subfields to be the same. Specifically, the first AP (AP1) and the second AP (AP2) set the values ​​of the RDG / MorePPDU subfields to 1 and send synchronized PPDUs. In addition, the first station STA1 and the second station STA2 set the values ​​of the RDG / MorePPDU subfields to 1 and send synchronized PPDUs. The first station STA1 and the second station STA2 set the values ​​of the RDG / MorePPDU subfields to 0 and send synchronized additional PPDUs.

[0235] Furthermore, when a multi-link device initiates RD exchanges and performs error recovery on multiple links, error recovery can be performed simultaneously on multiple links. That is, error recovery can be performed on all of the multiple links, or it can be performed on none of the multiple links. This embodiment can be applied when the RD initiator is a non-STR multi-link device or the RD responder is a non-STR device. This is because when error recovery is performed only on any one link, it may be difficult to send synchronized PPDUs on multiple links.

[0236] When the RD initiator is a multi-link device and the RD responder is also a multi-link device, and signaling regarding RD exchange is transmitted through any one of the links, the signaling regarding RD exchange can be applied not only to the corresponding link but also to the remaining links in the multiple links. In this case, the signaling regarding RD exchange can include at least any one of the aforementioned RDG, information about additional PPDUs, and AC restriction signaling information. In this case, information about RDG and additional PPDUs can be transmitted through the aforementioned RDG / More PPDU subfield. For example, the RD initiator as a multi-link device and the RD responder as a multi-link device can be associated with each other in the first and second links. In this case, when an RDG is transmitted in the first link, it can be assumed that an RDG was transmitted in the second link. Furthermore, if an additional PPDU is signaled as being transmitted in the first link, it can be assumed that the additional PPDU was also transmitted in the second link. This embodiment can be applied to the case of transmitting synchronization PPDUs. Furthermore, even if a frame is successfully received in one link but fails to be received in another link, the signaling regarding RD exchange can be applied not only to the corresponding link but also to the remaining links in the multiple links. Thus, even if transmission fails in any one link, RD exchange can be reliably performed in multiple links.

[0237] The IEEE 802.11be standard supports 320MHz, twice the maximum bandwidth of the traditional IEEE 802.11 standard's 160MHz. Furthermore, in standards prior to IEEE 802.11be, preamble puncturing was limited to DL (downlink) MU PPDUs, and the resource unit (RU) allocated to each station was restricted to a single, consecutive RU (996 per tone). In IEEE 802.11be, preamble puncturing is allowed even in uplink (UL) transmissions, and two or more non-consecutive RUs can be allocated to each station. In this case, considering implementation difficulty and efficiency, some combinations of RUs may not be permitted.

[0238] Figure 21 The diagram illustrates a RU configuration that can be assigned to a station in IEEE 802.11ax and a RU configuration that can be assigned to a station according to an embodiment of the present invention.

[0239] Furthermore, the IEEE 802.11be standard also supports small RUs (rulers) with frequencies less than 20MHz and 242 tones. Specifically, in the IEEE 802.11be standard, 26+52 tone RUs, 26+52 tone RUs, and 26+52 tone RUs can be assigned to stations. Figure 21 The description of small RU has been omitted.

[0240] Figure 11 (a) illustrates a 996-tone RU in an 80MHz channel and a 996-tone H RU in a 160MHz channel according to the IEEE 802.11ax standard. In IEEE 802.11ax, when an AP triggers a UL transmission over a bandwidth exceeding 40MHz to a station using a trigger frame, the AP can allocate only consecutive 80MHz or 160MHz RUs to the station. In this case, when the AP triggers a UL OFDMA transmission to the station and allocates a bandwidth exceeding 40MHz to the station, the AP can allocate only 80MHz RUs to the station. Furthermore, when the AP performs DL OFDMA in IEEE 802.11ax while using RUs exceeding 40MHz, only 80MHz RUs are allowed.

[0241] Figure 11 (b) illustrates the four types of 60MHz (242+484 tone size) RUs allowed in an 80MHz channel and the four types of 120MHz (484+996 tone size) RUs allowed in a 160MHz channel according to the IEEE 802.11be standard. In the IEEE 802.11be standard, when an AP uses a trigger frame to allocate RUs exceeding 40MHz to a station, the AP can allocate not only 80MHz RUs but also the four types of 60MHz RUs. Furthermore, the AP can allocate either the four types of 120MHz RUs or the four types of 160MHz RUs to a station. Moreover, these various types of RUs can be used not only for UL transmissions but also for DL ​​PPDUs using OFDMA. (See reference...) Figure 22 Describe the effects obtained when using various types of RUs.

[0242] Figure 22 The IEEE 802.11ax standard and the OFDMA DL PPDU used in embodiments of the present invention are shown.

[0243] exist Figure 22 In this example, the AP transmits OFDMA DL PPDUs to the first station STA1 and the second station STA2. In this case, the OFDMA DL PPDU includes a first PPDU (PPDU1) and a second PPDU (PPDU2). The frequency bandwidth allocated to the first PPDU (PPDU1) and the second PPDU (PPDU2) varies due to different modulation and coding schemes (MCS) used to encode the first PPDU (PPDU1) and the second PPDU (PPDU2). As mentioned above, using minimum padding among multiple PPDUs is efficient when the frequency bandwidth that can be allocated to multiple PPDUs transmitted simultaneously differs from each other. However, if the available RUs are limited, it may be necessary to abandon transmission to any one station or over-padding may be necessary.

[0244] Figure 22 (a) illustrates the case where the AP transmits OFDMA DLPPDUs using only the RU allocations allowed by the IEEE 802.11ax standard. The AP uses an 80MHz RU to transmit the first PPDU (PPDU1) and the second PPDU (PPDU2) to both the first station STA1 and the second station STA2. Therefore, a large amount of padding is used in the transmission of the first PPDU (PPDU1).

[0245] Figure 22 (b) illustrates a scenario where the AP transmits OFDMA DLPPDUs using only the RU allocations permitted by the IEEE 802.11ax standard. Since RUs with varying bandwidths can be allocated, this is related to... Figure 22 Compared to (a), Figure 22 (b) uses less padding. Not only in Figure 22 The OFDMA DL PPDU described herein can also improve transmission efficiency when using RUs of various bandwidths in a TB PPDU.

[0246] In the existing 802.11 standard, the CCA (Continuous Channel Access) process is based on the 20MHz primary channel for backoff procedures. (In this specification, the 20MHz primary channel refers to a primary channel with a bandwidth of 20MHz.) Specifically, even when accessing channels exceeding 20MHz, access to channels other than the 20MHz primary channel is only permitted if the CCA result of the 20MHz primary channel is idle. As the maximum bandwidth available to a station increases, the inefficiency of this channel access method may increase. Therefore, even when the 20MHz primary channel is busy, a method is needed to perform channel access via channels other than the 20MHz primary channel.

[0247] In a specific embodiment, the station can use a sub-channel that is not the 20MHz main channel to perform the backoff procedure. In this case, the station can only use a sub-channel that is not the 20MHz main channel to perform the backoff procedure if the 20MHz main channel is detected to be busy. Specifically, if the 20MHz main channel is detected to be busy and the destination station of the PPDU transmitted on the 20MHz main channel is not the station, the station can use a sub-channel that is not the 20MHz main channel to perform the backoff procedure. Therefore, the station can use a sub-channel that is not the 20MHz main channel to perform the backoff procedure only when the station decodes the preamble of the PPDU received on the 20MHz main channel. Furthermore, the station can determine the STA-ID of the EHT-SIG by decoding the preamble of the PPDU. In another specific embodiment, the station can determine the expected receiver of the MAC frame by decoding the first MAC frame of the PPDU. Furthermore, when a station determines that a PPDU received on the 20MHz main channel was transmitted in a BSS that is not part of its own BSS (i.e., an inter-BSS PPDU), the station can use a sub-channel that is not the 20MHz main channel to perform a backoff procedure. For this purpose, the station can determine the BSS color (HE-SIG or U-SIG) by decoding the PPDU's preamble. When a station determines that a PPDU transmitted on the 20MHz main channel is an inter-BSS PPDU, the station can omit the process of determining whether the intended receiver of the PPDU is itself.

[0248] In addition, if a subchannel is to be idle during DIFS, the station can initiate a backoff process using a subchannel that is not the 20MHz main channel.

[0249] An embodiment can be applied to compensate for the time required to decode the preamble of a PPDU transmitted on a 20MHz main channel. During a backoff process using a subchannel instead of the 20MHz main channel, the backoff counter can be decremented by a predetermined number, and the backoff process can begin. In this case, the predetermined number can be determined based on the time required to decode the PPDU preamble. For example, if the time required to decode the PPDU preamble is three time slots (e.g., 27µs), the predetermined number could be 3. In another specific embodiment, the backoff process can be performed without such compensation. (See also...) Figures 23 to 27 Describes a method for performing a backoff process using a sub-channel that is not a 20MHz main channel.

[0250] Figure 23 The backoff process for using a sub-channel as a non-20MHz main channel according to an embodiment of the present invention is illustrated.

[0251] During the backoff process, the station performs CCA on a time-slot basis. As a result of CCA, when the channel is idle, the station decrements the backoff counter value by 1. As a result of CCA, if the channel is not idle, the station retains the backoff counter value. As described above, even when performing the backoff process in a sub-channel that is not a 20MHz main channel, CCA can be performed on a time-slot basis. Furthermore, the bandwidth of a sub-channel that is not a 20MHz main channel can also be 20MHz.

[0252] The number of channels that a station can use as a non-20MHz primary channel for performing a backoff procedure can be two or more. For example, when a station operates on an 80MHz channel, it can perform channel access based on a backoff procedure using three 20MHz sub-channels. The number of sub-channels that a station can use as a non-20MHz primary channel for performing a backoff procedure can be determined based on the station's capabilities. In another specific embodiment, the number of sub-channels that a station can use as a non-20MHz primary channel for performing a backoff procedure can be a predetermined number. In this case, the predetermined number can be 1 or 2.

[0253] The station can separately set and manage the back-off counter used in the 20MHz main channel and the back-off counter used in sub-channels that are not 20MHz main channels. Specifically, the station can change the back-off counter for each channel based on the channel access result. That is, when the station successfully transmits on a channel, the station can obtain a new back-off counter for the corresponding channel within the CW_min period of the back-off counter used for that channel. If the station fails to transmit on a channel, the station can either double the CW value of the back-off counter used for that channel or obtain a new back-off counter for the corresponding channel within the CWmax period. Figure 23 (b) shows the settings and management of the backoff counter for each sub-channel. Figure 23 In (b), the station sets the initial value of the back-off counter to 4 in the 20MHz main channel P20 and sets the initial value of the back-off counter to 5 in the first sub-channel S20_1. After the station transmits PPDUs in the first sub-channel S20_1, the second sub-channel S20_2, and the third sub-channel S20_3, the station performs channel access again in the 20MHz main channel. In this case, the station uses the back-off counter for the 20MHz main channel as before.

[0254] The station can set up and manage a backoff counter shared in the 20MHz main channel and in sub-channels that are not 20MHz main channels. Figure 23 (a) illustrates the use of a common backoff counter in both the 20MHz main channel and the sub-channels that are not part of the 20MHz main channel. Figure 23In (a), the station sets the initial value of the back-off counter to 5 in the 20MHz main channel P20. Because the 20MHz main channel P20 is idle for three time slots, the station decrements the back-off counter by 3. Then, since the 20MHz main channel P20 is not idle, and the first sub-channel S20_1 is idle during the DIFS period, the station begins the back-off process in the first sub-channel S20_1. In this case, since the first sub-channel S20_1 is idle for three time slots, and the second sub-channel S20_2 and the third sub-channel S20_3 are idle during the PIFS period, the station transmits PPDUs in the first sub-channel S20_1, the second sub-channel S20_2, and the third sub-channel S20_3. The station then performs channel access by obtaining a new back-off counter. Figure 23 Unlike embodiment (a), when it is detected that the first subchannel S20_1 is also not idle and the station can perform a backoff procedure in the second subchannel S20_2, the station can perform a backoff procedure in the second subchannel S20_2. In this case, if the backoff procedure cannot be performed even in the second subchannel S20_2, the station can wait until the 20MHz main channel P20 or the first subchannel S20_1 is idle.

[0255] When a station successfully accesses and transmits a PPDU on a sub-channel that is not the 20MHz main channel, the length of the PPDU can be limited. First, when a station performs channel access and transmission via a sub-channel that is not the 20MHz main channel, the AP associated with the station cannot perform transmission and reception on the 20MHz main channel. Therefore, scanning and other operations performed via the 20MHz main channel cannot be performed. Furthermore, since inter-BSS PPDUs transmitted via the 20MHz main channel cannot be received, NAV cannot be set based on inter-BSS PPDUs. Therefore, the length of the PPDU needs to be limited when a station successfully accesses and transmits a PPDU on a sub-channel that is not the 20MHz main channel. Furthermore, considering the balance with stations according to existing standards, the length of the PPDU also needs to be limited when a station successfully accesses the channel and transmits a PPDU on a sub-channel that is not the 20MHz main channel. Additionally, as mentioned above, the number of sub-channels on which a station can perform a backoff procedure can be limited. (Refer to...) Figure 24 This embodiment will be described in detail.

[0256] Figure 24 This illustrates a scenario where, according to an embodiment of the invention, a station successfully accesses a sub-channel that is not a 20MHz main channel and transmits a PPDU, but the length of the PPDU is limited.

[0257] When a station successfully accesses a sub-channel that is not the 20MHz main channel and transmits a PPDU, the station can terminate the transmission of the PPDU within a time point determined based on the transmission of the inter-BSS PPDU transmitted in the 20MHz main channel. In this case, the time point determined based on the transmission of the inter-BSS PPDU can be the end time point of the inter-BSS PPDU. In another specific embodiment, the time point determined based on the transmission of the inter-BSS PPDU can be the time point at which the ACK for the transmission of the inter-BSS PPDU is completed. The station can determine the time point determined based on the value of the length field of the L-SIG of the inter-BSS PPDU. Furthermore, the station can determine the time point determined based on the value of the TXOP field of the signaling field of the inter-BSS PPDU.

[0258] exist Figure 24 In one embodiment, the station transmits PPDUs within the length of the inter-BSS PPDU (OBSS PPDU) transmitted in the 20MHz main channel P20 via the first sub-channel S20_1, the second sub-channel S20_2, and the third sub-channel S20_3.

[0259] When a station is permitted channel access in a sub-channel that is not the 20MHz main channel, the AP must perform PPDU detection not only on the 20MHz main channel but also on other sub-channels in order to receive PPDUs. Specifically, when transmitting inter-BSS PPDUs on the 20MHz main channel, the AP can perform PPDU detection not only on the 20MHz main channel but also on sub-channels. PPDU detection can detect the PPDU preamble. In this embodiment, the AP can detect PPDUs in sub-channels where no inter-BSS PPDUs are being transmitted. In this case, the order in which the AP detects PPDUs on sub-channels can be predetermined. For example, when transmitting an inter-BSS PPDU with a bandwidth of 40MHz on the 20MHz main channel, the AP can detect PPDUs on a sub-channel 40MHz away from the 20MHz main channel.

[0260] Additional processing is required to receive PPDUs transmitted on channels that do not include the 20MHz main channel. Therefore, a station may not support the reception of PPDUs transmitted on channels that do not include the 20MHz main channel. A station can signal whether it supports the reception of PPDUs transmitted on channels that do not include the 20MHz main channel. Specifically, a station can use a capability element to signal to the AP whether it supports the reception of PPDUs transmitted on channels that do not include the 20MHz main channel. When the AP configures a PPDU on a channel that does not include the 20MHz main channel, the AP can include only frames from stations that have signaled support for the reception of PPDUs transmitted on channels that do not include the 20MHz main channel in the PPDU.

[0261] In the IEEE 802.11be standard, segments can be divided in 80MHz increments; this can be referred to as 80MHz segmentation. Furthermore, within a single PPDU, different signaling fields (e.g., EHT-SIG or U-SIG) are transmitted in 80MHz segments. Figure 25 The text describes a scenario where a station performs channel access through segments that do not include the 20MHz main channel.

[0262] Figure 25 An embodiment of the invention is shown, in which, when the 20MHz main channel is not idle, the station performs channel access through a sub-channel of a segment that is a non-main segment.

[0263] As described above, a station can perform channel access by excluding segments of the 20MHz main channel. Specifically, if the 20MHz main channel is not idle, the station can perform channel access by excluding segments of the 20MHz main channel.

[0264] In another specific embodiment, the station can be configured to receive and decode the preamble via sub-channels other than the 20MHz main channel. In this case, the station can perform channel access via segments excluding the 20MHz main channel. In this embodiment, the station can perform channel access via segments excluding the 20MHz main channel without detecting whether a PPDU has been transmitted on the 20MHz main channel. Transmission via segments excluding the 20MHz main channel can be referred to as subchannel selective transmission (SST). Furthermore, a station that receives the preamble and PPDU via segments excluding the 20MHz main channel can be referred to as a parked station.

[0265] A subchannel for performing channel access can be specified for each segment. If the 20MHz main channel is not idle, the station can perform channel access in segments that do not include the 20MHz main channel, and in the specified subchannel.

[0266] exist Figure 15 In this embodiment, the AP detects an inter-BSS PPDU with a bandwidth of 40MHz transmitted on the 20MHz main channel P20. The AP performs a back-off procedure in the first sub-channel S20_1 of the second segment (Segment 2). In this case, when performing the back-off procedure in the second segment (Segment 2), the first sub-channel S20_1 can be the channel designated as the channel for performing the back-off procedure. The station docked in the second segment (Segment 2) detects the preamble of the PPDU in the first sub-channel S20_1. In this case, the station docked in the second segment (Segment 2) can wait for the reception of the PPDU in the first sub-channel S20_1, regardless of whether the channel on which the AP performs the back-off procedure is the 20MHz main channel P20 or the first sub-channel S20_1. Furthermore, stations docked in the second segment (Segment2) can detect the preamble of the HE MU PPDU or EHT MU PPDU in the first sub-channel S20_1, and stations docked in the second segment (Segment2) can decode the preamble of the PPDU in sub-channels other than the first sub-channel S20_1 of the second segment (Segment2) to determine the special stream and RU of the PPDU to be sent to the station.

[0267] The AP can transmit PPDUs not only in Segment 2, but also on sub-channels that were idle during the previous PIFS period at the time the fallback process ends in Segment 2. In this case, the AP can determine whether to transmit PPDUs in each segment during the PIFS period before the fallback process ends, based on whether the channel designated to perform the fallback process in each segment is idle. Specifically, if the channel designated to perform the fallback process in each segment is idle during the PIFS period before the fallback process ends, the AP can transmit PPDUs in the corresponding segment. If the channel designated to perform the fallback process in each segment is not idle during the PIFS period before the fallback process ends, the AP may not transmit PPDUs in the corresponding segment.

[0268] exist Figure 25In the embodiment, during the PIFS period prior to the end of the backoff process in the second segment (Segment 2), it is detected that the second sub-channel S20_2, which is the sub-channel performing the backoff process in the third segment (Segment 3), is not idle. Furthermore, during the PIFS period prior to the end of the backoff process in the second segment (Segment 2), it is detected that the third sub-channel S20_3, which is the sub-channel performing the backoff process in the fourth segment (Segment 4), is idle. Therefore, the AP transmits PPDUs in both the second and fourth segments (Segment 2 and Segment 4).

[0269] As described above, constraints can be applied to the length of the transmitted PPDU, the expected receiver of the MAC frame included in the PPDU, and the RU assigned to the station receiving the PPDU.

[0270] Although the transmission of an AP has been described in the above embodiments, the above embodiments can also be applied to non-AP stations. This will be referred to... Figure 26 Provide a detailed description.

[0271] Figure 26 An embodiment of the invention is shown, in which a first AP of a multi-link device signals to a second AP that reception can be performed via a sub-channel that is not a 20MHz main channel.

[0272] When the first access point (AP) of a multi-link device detects that its 20MHz main channel is not idle, the first AP can signal to perform a backoff procedure via a sub-channel that is not the 20MHz main channel, through a second AP (another AP in the multi-link device). In this case, the first AP can indicate the sub-channel to be used for the backoff procedure through the second AP. In another specific embodiment, the first AP can signal the sub-channel to be used for the backoff procedure without using the second AP. In this case, the station can perform the backoff procedure through a predetermined sub-channel.

[0273] Furthermore, the first AP can signal to the second AP the time it needs to wait for reception in a sub-channel that is not the 20MHz main channel. The station can determine the length of the UL PPDU based on the signaled waiting time. Specifically, the station can determine the length of the UL PPDU such that the transmission of the UL PPDU does not continue beyond the signaled waiting time. In another specific embodiment, the station can determine the length of the UL PPDU such that it exceeds the signaled waiting time before completing the response to the UL PPDU (e.g., ACK).

[0274] In this embodiment, the second AP may send a control frame including information related to receive waiting, such as information related to the first AP's sub-channel as a non-20MHz primary channel and information related to the waiting time. In this case, the receiver address of the control frame may be the MAC address of a specific station. In this case, only the station corresponding to the receiver address can perform the backoff procedure on the sub-channel as a non-20MHz primary channel. In another specific embodiment, the receiver address may be a multicast address. In this case, only the station corresponding to the multicast address can perform the backoff procedure on the sub-channel as a non-20MHz primary channel. In this case, multiple stations can compete for channel access. In another specific embodiment, the receiver address may be a broadcast address. Stations not corresponding to the receiver address can maintain a power-saving state during the receive waiting time.

[0275] In the above embodiments, a control frame including information about receiving a pending message may be sent as a single frame or multiple frames may be sent. A control frame including information about receiving a pending message may be sent alone. In another specific embodiment, a control frame including information about receiving a pending message may be sent together with a data frame, another control frame, or a management frame.

[0276] Furthermore, the second AP can signal the TID, which can be transmitted based on a backoff process using a sub-channel that is not the 20MHz main channel. Specifically, the aforementioned control frame can include information about the TID, which can be used in uplink transmissions transmitted based on a backoff process using a sub-channel that is not the 20MHz main channel. In this case, the information about the TID can be represented by an 8-bit field. Specifically, each bit of the 8-bit field can correspond to a TID value from 0 to 7. If the value of each bit is 1, it can indicate that the TID corresponding to the corresponding bit is allowed. If the value of the sub-field is 11111111 2b This allows TID values ​​from 0 to 7. In another specific embodiment, if the value of the subfield is 11111111 2b This indicates that the transmission of all TIDs is permitted. In another embodiment, the information about the TID can be represented by a 16-bit field. Specifically, each bit of the 16-bit field can correspond to a TID value from 0 to 15. If the value of each bit is 1, it indicates that the TID corresponding to the corresponding bit is permitted.

[0277] Furthermore, the second AP can signal the EDCA parameters used during the back-off process in a sub-channel that is not a 20MHz main channel. Specifically, the control frame mentioned above may include information about the EDCA parameters used during the back-off process in a sub-channel that is not a 20MHz main channel. The first station STA1 performs the back-off process on the sub-channel that is not a 20MHz main channel using the back-off parameters signaled. In a specific embodiment, even if the first station STA1 uses the MU-EDCA parameters, the first station STA1 can still perform the back-off process on the sub-channel that is not a 20MHz main channel using the back-off parameters signaled. In this case, when the first station STA1 completes the back-off process in a sub-channel that is not a 20MHz main channel or performs the back-off process in a 20MHz main channel, the first station STA1 can again use the MU-EDCA parameters to perform the back-off process.

[0278] exist Figure 16 In one embodiment, the AP multilink device includes a first AP (AP1) and a second AP (AP2). The non-AP multilink device includes a first station STA1 and a second station STA2. The first AP (AP1) and the first station STA1 are associated on a first link (link 1). The second AP (AP2) and the second station STA2 are associated on a second link (link 2). In this case, it is detected that the 20MHz main channel of the first AP (AP1) is not idle. The second AP (AP2) sends information about the receive wait of the first AP (AP1) to the second station STA2, for example, information about the receive wait sub-channel and the receive wait time. In this case, the second AP (AP2) uses a control frame to send the receive wait information on the second link (link 2). In this case, the receiver address of the control frame can be the first station STA1. In another embodiment, the receiver address of the control frame can be the MAC address of the non-AP multilink device including the first station STA1 and the second station STA2. In another embodiment, the receiver address of the control frame can be a multicast address. The first station STA1 performs a backoff procedure on a sub-channel (P20) that is not the 20MHz main channel. After the rollback process is successful, the PPDU is sent to the first AP (AP1).

[0279] According to an embodiment of the invention, the AP can dock the station associated with the AP in a segment that is a non-80MHz main channel. In this case, the station associated with the AP can operate on a sub-channel in the segment where the station is docked, just like a 20MHz main channel. Specifically, the station associated with the AP can detect the preamble of the PPDU from the segment where the station is docked. Furthermore, even if the AP transmits a PPDU with a bandwidth of 320MHz, the station associated with the AP can receive it as if it were receiving a PPDU with a bandwidth of 80MHz or 160MHz. This is because, as described above, the signaling fields of the PPDU (e.g., the U-SIG field and the EHT-SIG field) can be transmitted as different content in each segment. Furthermore, since the signaling fields can be transmitted as different content in each segment, excessive increases in the length of the signaling fields can be prevented.

[0280] In a segment where a station associated with an AP is docked, a subchannel used like a 20MHz main channel is called a virtual main channel. In this case, preamble piercing may not be performed in the virtual main channel. Furthermore, a virtual main channel can be designated for each segment. Specifically, within a segment, the lowest 20MHz channel can be designated as the virtual main channel. If the AP cannot transmit the preamble of a PPDU in the virtual main channel of any segment, the AP can pierce the corresponding segment. In another specific embodiment, when the AP cannot transmit the preamble of a PPDU in the virtual main channel of any segment, the AP can send the PPDU to a station not docked in that segment. That is, if the AP cannot transmit the preamble of a PPDU on the virtual main channel of any segment, the station docked in that segment cannot receive the PPDU. Furthermore, when the AP pierces any segment, the AP may not trigger uplink transmissions at stations docked in that segment. Specifically, the AP may not send trigger frames to stations docked in that segment to allocate RUs for uplink transmissions.

[0281] When a station docked in a segment of a non-80MHz main channel is restricted to channel access in the 20MHz main channel (non-virtual main channel), the channel used by the AP for transmission and the channel used to detect the preamble of the PPDU can be different. Furthermore, the channel used by the station for backoff for uplink transmission and the channel used to detect the preamble of the PPDU can also be different. Therefore, when the AP performs backoff for a station docked in a segment of a non-80MHz main channel, the AP may be unable to receive PPDUs transmitted by the station docked in that segment. Therefore, the AP can allow stations docked in segments of a non-80MHz main channel to perform backoff procedures for uplink transmission on the segment in which they are docked. This will refer to... Figure 27 Describe it.

[0282] Figure 27 The AP multi-link device shown according to an embodiment of the present invention allows a station docked in a segment of a non-80MHz main channel to perform a backoff process for uplink transmission in the segment in which it is docked.

[0283] When an inter-BSS PPDU is detected being transmitted on the 20MHz main channel, a station may allow stations docked in segments other than the 80MHz main channel to perform a backoff procedure for uplink transmission on the virtual main channel. In this case, the AP can determine the segments for which the station will perform the backoff procedure for uplink transmission based on the bandwidth of the inter-BSS PPDU transmitted on the 20MHz main channel. Specifically, the AP may determine segments for which no inter-BSS PPDUs have been transmitted as segments for which the station will perform a backoff procedure for uplink transmission. In this case, the AP may allow stations docked in the determined segments to perform the backoff procedure using the virtual main channel of the determined segments. In this case, the AP may only allow some of the stations docked in the determined segments to perform the backoff procedure using the virtual main channel. For example, when an inter-BSS PPDU with a bandwidth of 160MHz is transmitted through two segments, the AP may allow stations docked in the remaining two segments to perform the backoff procedure using the virtual main channel. In this scenario, the AP may allow only stations docked in one of the two segments to perform the backoff process using the virtual master channel.

[0284] Furthermore, the AP can use a 2-bit subfield to signal which segments are allowed to perform a fallback procedure using the virtual master channel. For ease of description, the segments allowed to perform a fallback procedure using the virtual master channel are referred to as designated segments. In this case, the subfield can represent the index of the designated segment. For example, if the value of the subfield is 0, it can indicate that the segment corresponding to the lowest frequency band is the designated segment. If the value of the subfield is 3, it can indicate that the segment corresponding to the highest frequency band is the designated segment. In another specific embodiment, if the value of the subfield is 0, it can indicate that the segment corresponding to the 80MHz master channel is the designated segment. In this case, if the value of the subfield is 1, it can indicate that the segment corresponding to the 80MHz subchannel is the designated segment. Furthermore, when the value of the subfield is 2 or 3, it can indicate that each of the two segments corresponding to the 160MHz subchannel is a designated segment.

[0285] In addition, the AP can signal PPDU reception waiting time information to the station. This PPDU reception waiting time information is information about the time the AP waits for PPDU reception on the virtual master channel. Specifically, the AP can signal the PPDU reception waiting time information along with a specified segment to the station. In this case, the station can determine the length of the PPDU to be transmitted based on the PPDU reception waiting time information. Specifically, the station can determine the length of the PPDU such that the PPDU transmission completion time does not exceed the PPDU reception waiting time. In another specific embodiment, the station can determine the length of the PPDU such that the PPDU and the response to the PPDU completion time do not exceed the PPDU reception waiting time. The response to the PPDU can be an ACK (e.g., an ACK frame and a BlockAck frame).

[0286] In addition, the AP can signal to the station the type of service sent according to the backoff procedure on the virtual master channel. Specific AP and station operations can be found in the reference. Figure 26 The operation of the AP and station in the described embodiment is the same. Furthermore, the AP can use signaling to notify the station of the EDCA parameters to be used when the station performs a backoff procedure on the virtual master channel. Specific AP and station operations can be found in the referenced... Figure 26 The AP and station operate identically in the described embodiments. In this case, the EDCA parameters used when the station performs a backoff procedure on the 20MHz main channel and the EDCA parameters used when the station performs a backoff procedure on the virtual main channel can be independent. For example, the backoff counter used when performing a backoff procedure on the 20MHz main channel and the backoff counter used when performing a backoff procedure on the virtual main channel can be independent.

[0287] In addition, the AP multi-link device can send the above information to the station associated with the first AP through the second AP of the multi-link device.

[0288] Furthermore, stations docked on segments other than those of the virtual master channel that allow the AP to perform a backoff procedure can enter a power-saving state based on the reception waiting time information described above. Specifically, stations docked on segments other than those of the virtual master channel that allow the AP to perform a backoff procedure can remain in a power-saving state during the reception waiting time.

[0289] exist Figure 27In this embodiment, the AP multi-link device includes a first AP and a second AP. In this case, the first AP detects that an inter-BSS PPDU has been transmitted in its 20MHz master channel P20. The first AP (AP1) signals permission for a backoff process for uplink transmission via the second AP (AP2) on the virtual master channel of the second segment (Segment2) instead of the first segment (Segment1) which includes the 20MHz master channel P20. In this case, while the first AP (AP1) is allowed to perform the backoff process for uplink transmission in the second segment (Segment2), it signals the link operated by the first AP (AP1), the uplink transmission time limit, the TID of the service to be transmitted in the uplink transmission, and the EDCA parameters to be used in the backoff process for uplink transmission.

[0290] 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 constituent elements and operations of the invention can be implemented using a computer system with a general-purpose hardware architecture.

[0291] The features, structures, effects, etc., described in the above embodiments are included in at least one embodiment of the present invention, but are not necessarily limited to one embodiment. Furthermore, the features, structures, effects, etc., described in the various embodiments can be combined or modified by those skilled in the art to create other embodiments. Therefore, anything relating to such combinations and modifications should be interpreted as being included within the scope of the present invention.

[0292] The above 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 shown, 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 multi-link apparatus using multiple links, the multi-link apparatus comprising: a transceiver; and a processor, wherein the processor is configured to receive, in a first link of the multiple links, a first physical layer protocol data unit, PPDU, including reverse direction, RD, grant and access category, AC, restriction signaling from a station that is a transmission opportunity, TXOP, holder or a service period, SP, source, wherein an AC or a traffic identifier, TID, is mapped to the first link, wherein the multi-link apparatus transmits a frame based on the AC or TID mapped in the first link, when the AC restriction signaling indicates that any TID is allowed as a TID of a data frame to be included in a second PPDU, and the multi-link apparatus includes a data frame in the second PPDU, including in the second PPDU a data frame corresponding to a TID mapped to the first link and not including in the second PPDU a data frame corresponding to a TID not mapped to the first link, and in response to the first PPDU, transmitting the second PPDU to the station in the first link, wherein an AC of a management frame is considered a predetermined value, and wherein the AC restriction signaling is included in a medium access control (MAC) header of a frame included in the first PPDU.

2. The multi-link apparatus of claim 1, wherein, when the AC restriction signaling indicates that an AC or TID of a frame to be included in the second PPDU is restricted, and the multi-link apparatus includes a data frame in the second PPDU, the processor is configured to include in the second PPDU a data frame corresponding to an AC or TID that is mapped to the first link and has a priority higher than or equal to a priority of the AC or TID of a frame included in the first PPDU, and not to include in the second PPDU a data frame corresponding to a TID or AC that is not mapped to the first link or has a priority lower than the priority of the AC or TID of the frame included in the first PPDU.

3. The multi-link device of claim 2, wherein, when the first PPDU includes a plurality of frames, the priority of the AC or TID of the frame included in the second PPDU is the lowest priority among priorities of the plurality of frames.

4. The multi-link device of claim 1, wherein, when a BlockAck frame is included in the second PPDU, the processor is configured to determine an AC of the BlockAck frame based on a TID field of the BlockAck frame, and when a BlockAckReq frame is included in the second PPDU, the processor is configured to determine an AC of the BlockAckReq frame based on a TID field of the BlockAckReq frame.

5. A method of operating a multi-link apparatus using multiple links, the method comprising: receiving, in a first link of the plurality of links, a first physical layer protocol data unit, PPDU, including reverse direction, RD, grant and access category, AC, restriction signaling from a station that is a transmission opportunity, TXOP, holder or a service period, SP, source, wherein an AC or a traffic identifier, TID, is mapped to the first link of the plurality of links, wherein the multi-link apparatus transmits a frame based on the mapped AC or TID in the first link; including a data frame corresponding to a TID mapped to the first link in the second PPDU; when the AC restriction signaling indicates that any TID is allowed as a TID of a data frame to be included in a second PPDU, and the multi-link apparatus includes a data frame in the second PPDU, not including a data frame corresponding to a TID not mapped to the first link in the second PPDU; and transmitting, in the first link, the second PPDU to the station in response to the first PPDU, wherein an AC of a management frame is considered as a predetermined value, and wherein the AC restriction signaling is included in a medium access control (MAC) header of a frame included in the first PPDU.

6. The method of claim 5, wherein transmitting the second PPDU to the station includes including a data frame corresponding to an AC or TID mapped to the first link and having a priority higher than or equal to a priority of an AC or TID of a frame included in the first PPDU in the second PPDU, and when the AC restriction signaling indicates that an AC or TID of a frame to be included in the second PPDU is restricted, and the multi-link apparatus includes a data frame in the second PPDU, not including a data frame corresponding to a TID or AC not mapped to the first link or having a priority lower than the priority of the AC or TID of the frame included in the first PPDU in the second PPDU.

7. The method of claim 6, wherein, when the first PPDU includes a plurality of frames from the station, the priority of the AC or TID of the frame included in the second PPDU is a lowest priority among priorities of the plurality of frames.

8. The method of claim 5, wherein, transmitting the second PPDU to the station includes determining an AC of a BlockAck frame based on a TID field of the BlockAck frame when the BlockAck frame is included in the second PPDU, and determining an AC of a BlockAckReq frame based on a TID field of the BlockAckReq frame when the BlockAckReq frame is included in the second PPDU.

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