CN116830754A

CN116830754A - Wireless communication method using multilink and wireless communication terminal using the same

Info

Publication number: CN116830754A
Application number: CN202280014346.XA
Authority: CN
Inventors: 高建重; 孙周亨; 金相贤; 郭真三
Original assignee: Wilus Institute of Standards and Technology Inc
Current assignee: Wilus Institute of Standards and Technology Inc
Priority date: 2021-02-10
Filing date: 2022-02-10
Publication date: 2023-09-29

Abstract

A method of transmitting a frame by a Station (STA) in a wireless communication system is disclosed. The STA according to the present invention receives a trigger frame indicating uplink transmission from an Access Point (AP) and transmits a physical layer protocol data unit (PPDU) to the AP and/or another STA within a shared TXOP based on the trigger frame. Here, the trigger frame is used to share part or all of a transmission opportunity (TXOP) obtained by the AP to the STA. Further, the PPDU includes duration information indicating a TXOP for transmitting the PPDU, and wherein the duration information is set based on the shared TXOP.

Description

Wireless communication method using multilink and wireless communication terminal using the same

Technical Field

The present invention relates to a wireless communication method using multiple links and a wireless communication terminal using the same, and more particularly, to a method and terminal for transmitting and receiving data by setting a TXOP.

Background

In recent years, as the supply of mobile devices expands, wireless LAN (Wireless LAN) technology capable of providing rapid wireless internet services to mobile devices has been paid attention to. Wireless LAN technology allows mobile devices, including smart phones, smart tablets, laptop computers, portable multimedia players, embedded devices, etc., to wirelessly access the internet in a home or company or special service providing area based on short-range wireless communication technology.

Since the initial wireless LAN technology is supported using a frequency of 2.4GHz, the institute of electrical and electronics engineers (Institute of Electrical and Electronics Engineers, IEEE) 802.11 has commercialized or developed various technical standards. First, IEEE 802.11b supports a maximum communication speed of 11Mbps when using frequencies of the 2.4GHz band. Compared to the frequency of the significantly congested 2.4GHz band, the IEEE 802.11a commercialized after the IEEE 802.11b uses frequencies other than the 2.4GHz band but the 5GHz band to reduce the influence of interference, and increases the communication speed to a maximum of 54Mbps by using the OFDM technology. However, the disadvantage of IEEE 802.11a is that the communication distance is shorter than IEEE 802.11b. Further, similar to IEEE 802.11b, IEEE 802.11g uses a frequency of 2.4GHz band to achieve a communication speed of a maximum of 54Mbps and satisfies backward compatibility to be significantly focused, and further, is superior to IEEE 802.11a in terms of communication distance.

Further, as a technical standard established to overcome a limitation of a communication speed pointed out as a vulnerability in a wireless LAN, IEEE 802.11n has been provided. IEEE 802.11n aims to increase the speed and reliability of the network and to extend the working distance of the wireless network. In more detail, IEEE 802.11n supports High Throughput (HT), in which a data processing speed is 540Mbps or more at maximum, and further, is based on a multiple input and multiple output (Multiple Inputs Multiple Outputs, MIMO) technology, in which a plurality of antennas are used at both sides of a transmission unit and a reception unit to minimize a transmission error and optimize a data speed. Furthermore, the standard can use a compilation scheme that transmits multiple copies that are superimposed on each other in order to increase data reliability.

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

As wireless LAN standards after 802.11ac and 802.11ad, the IEEE 802.11ax (High Efficiency wireless LAN) standard for providing a High-Efficiency and High-performance wireless LAN communication technology in a High-density environment where an AP and a terminal are concentrated is in a development completion stage. In an 802.11 ax-based wireless LAN environment, in the presence of a high-density station and an Access Point (AP), communication with high frequency efficiency should be provided indoors/outdoors, and various technologies for realizing such communication have been developed.

In order to support new multimedia applications such as high definition video and real-time games, new wireless LAN standards have begun to be developed to increase the maximum transmission rate. In IEEE 802.11be extremely high throughput (Extremely High Throughput, EHT), which is the 7 th generation wireless LAN standard, standard development is underway with the aim of supporting transmission rates up to 30Gbps in the 2.4/5/6GHz band through a comparatively wide band, increased spatial streams, multi-AP cooperation, and the like. Techniques such as 320MHz bandwidth, multi-link (Multi-link) operation, multi-Access Point (Multi-AP) operation, and hybrid automatic repeat request (Hybrid Automatic Repeat Request, HARQ) are proposed in IEEE 802.11 be.

The multilink operation may be operated in various types according to its operation method and implementation method. In this case, since there may occur no problem that has occurred in the existing wireless LAN communication operation based on IEEE 802.11, it is necessary to define a detailed operation method in the multilink operation.

The background of the invention, on the other hand, is written to enhance understanding of the background and thus may contain something that is not in the prior art that is known to a person of ordinary skill in the art to which this technology pertains.

Disclosure of Invention

Technical problem

An object of the present invention is to provide a method and apparatus for transmitting and receiving data by setting a transmission opportunity (TXOP).

Further, another object of the present invention is to provide a method and apparatus for a non-AP STA to transmit and receive data by sharing a TXOP set by an Access Point (AP) to the non-AP STA.

Further, another object of the present invention is to provide a method and apparatus for setting a Network Allocation Vector (NAV) so that a non-AP STA transmits and receives data within a shared TXOP.

The technical problems to be achieved in the present specification are not limited to the above-mentioned technical problems, and other technical problems not mentioned can be clearly understood by those skilled in the art on the basis of the following description.

Solution method

A Station (STA) of a wireless communication system, the STA comprising a transceiver and a processor for controlling the transceiver, wherein the processor: receiving a trigger frame from an Access Point (AP) indicating an uplink transmission, wherein the trigger frame is used to share a portion or all of a transmission opportunity (TXOP) obtained by the AP; and transmitting a physical layer protocol data unit (PPDU) to the AP and/or another STA within the shared TXOP based on the trigger frame, wherein the PPDU includes duration information indicating a TXOP used to transmit the PPDU, wherein the duration information is set based on the shared TXOP.

Further, in the present invention, the termination time point of the duration indicated by the duration information may be the same as the termination time point of the shared TXOP.

Further, in the present invention, the duration indicated by the duration information may be terminated before the termination time point of the shared TXOP.

Further, in the present invention, when a Network Allocation Vector (NAV) is set in a TXOP through a frame transmitted by an AP, a PPDU is transmitted in a shared TXOP regardless of the set NAV.

Further, in the present invention, when the NAV and the NAV timeout period indicating the expiration time of the NAV are set by the other STA in the shared TXOP based on the trigger frame, the NAV set by the other STA in the shared TXOP is not released due to the expiration of the NAV timeout period even if the NAV timeout period expires in the shared TXOP.

Further, in the present invention, the trigger frame includes a subfield indicating whether or not the TXOP is shared through the trigger frame.

Further, in the present invention, when the subfield indicates sharing of the TXOP, a value of the subfield may indicate whether transmission and reception with another STA can be performed within the shared TXOP.

Further, in the present invention, the trigger frame includes a type field indicating a type of the trigger frame, and sharing of a part or all of the TXOP is set according to the type of the trigger frame based on the type field.

Furthermore, the present invention provides a method comprising: receiving a trigger frame from an Access Point (AP) indicating an uplink transmission, wherein the trigger frame is for sharing a portion or all of a transmission opportunity (TXOP) obtained by the AP to a STA; and transmitting a physical layer protocol data unit (PPDU) to the AP and/or another STA within the shared TXOP based on the trigger frame, wherein the PPDU includes duration information indicating a TXOP for transmitting the PPDU, and the duration information is set based on the shared TXOP.

Advantageous effects

According to an embodiment of the present invention, an AP may share a TXOP set by the AP to a non-AP STA, so that the non-AP STA may efficiently transmit and receive data.

Further, according to an embodiment of the present invention, in the shared TXOP, the non-AP STA may set a NAV for transmitting and receiving data based on the shared TXOP or interpret the set NAV according to the shared TXOP, so that data may be effectively transmitted.

The effects obtainable in the present invention are not limited to the above-described effects, and other effects not mentioned can be clearly understood by those skilled in the art to which the present invention pertains from the following description.

Drawings

Fig. 1 illustrates a wireless LAN system according to an embodiment of the present invention.

Fig. 2 illustrates a wireless LAN system according to another embodiment of the present invention.

Fig. 3 illustrates a configuration of a station according to an embodiment of the present invention.

Fig. 4 illustrates a configuration of an access point according to an embodiment of the present invention.

Fig. 5 schematically illustrates a process of setting up links for a station and an access point.

Fig. 6 illustrates a carrier sense multiple access (Carrier Sense Multiple Access, CSMA)/collision avoidance (Collision Avoidance, CA) method used in wireless LAN communication.

Fig. 7 illustrates an embodiment of a format of a PLCP protocol data unit (PLCP Protocol Data Unit, PPDU) for each of various standard generations.

Fig. 8 illustrates examples of various very high throughput (Extremely High Throughput, EHT) Physical Protocol Data Unit (PPDU) formats and methods for indicating the formats, according to an embodiment of the invention.

Fig. 9 is a diagram illustrating a multi-link (multi-link) device according to an embodiment of the present invention.

Fig. 10 is a diagram illustrating an example of a TID-to-link (TID-to-link) mapping method according to one embodiment of the invention.

Fig. 11 is a diagram illustrating an example of a multilink NAV setting operation according to an embodiment of the present invention.

Fig. 12 is a diagram illustrating another example of a multilink NAV setting operation according to an embodiment of the present invention.

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

Fig. 14 illustrates a wireless LAN function according to an embodiment of the present invention.

Fig. 15 illustrates an Uplink (UL) multi-user (MU) operation according to an embodiment of the present invention.

Fig. 16 illustrates a Trigger frame (Trigger frame) format according to an embodiment of the present invention.

Fig. 17 illustrates a method for indicating a trigger-based PPDU format according to an embodiment of the present invention.

Fig. 18 illustrates an example of UL MU operation according to an embodiment of the present invention.

Fig. 19 is a diagram illustrating an example of a method for sharing a TXOP in accordance with an embodiment of the present invention.

Fig. 20 illustrates a diagram of a method of sharing of a TXOP and NAV setting association in accordance with an embodiment of the present invention.

Fig. 21 is a diagram illustrating sharing of a TXOP and transmission of a CTS frame according to an embodiment of the present invention.

Fig. 22 is a diagram illustrating an example of a trigger frame for sharing a TXOP in accordance with an embodiment of the present invention.

Fig. 23 is a diagram illustrating NAV timeout (time out) according to an embodiment of the present invention.

Fig. 24 is a diagram illustrating sharing of TXOPs and NAV timeouts according to an embodiment of the present invention.

Fig. 25 is a diagram illustrating sharing of a TXOP and NAV timeout according to another embodiment of the present invention.

Fig. 26 is a diagram illustrating sharing of a TXOP and NAV timeout according to another embodiment of the present invention.

Fig. 27 is a diagram illustrating an example in which an STA and an AP apply NAV when TXOP sharing is applied according to an embodiment of the present invention.

Fig. 28 is a diagram illustrating STA-terminated TXOP sharing in accordance with an embodiment of the present invention.

Fig. 29 is a flowchart illustrating an example of the operation of a STA according to an embodiment of the present invention.

Detailed Description

The terms used in the present specification adopt general terms that are currently widely used by considering the functions of the present invention, but the terms may be changed according to the intention, habit, and appearance of new technology of those skilled in the art. Furthermore, in a particular case, there are terms arbitrarily selected by the applicant, and in this case, the meanings thereof will be explained in the corresponding description section of the present invention. Therefore, it should be understood that the terms used in the present specification should be analyzed not only based on the names of the terms but also based on the essential meaning of the terms and the contents of the entire specification.

Throughout the specification, when an element is referred to as being "coupled" to another element, it can be "directly coupled" to the other element or be "electrically coupled" to the other element via a third element. Furthermore, unless explicitly stated to the contrary, the word "comprising" will be understood to imply the inclusion of stated elements but not the exclusion of any other elements. Furthermore, restrictions such as "or above" or below "based on particular thresholds may be replaced with" greater than "or" less than "respectively, as appropriate. Hereinafter, in the present invention, fields and subfields may be used interchangeably.

The wireless LAN system includes one or more basic service sets (Basic Service Set, BSS), and the BSS represents a set of devices that are successfully synchronized with each other to communicate with each other. In general, BSSs may be divided into an infrastructure BSS (infrastructure BSS) and an Independent BSS (IBSS), and fig. 1 illustrates the infrastructure BSS therebetween.

As shown in fig. 1, the infrastructure BSS (BSS 1 and BSS 2) includes one or more stations (STA 1, STA 2, STA 3, STA 4, and STA 5), access points (AP-1 and AP-2) as stations providing a distributed service (Distribution Service), and a distributed system (Distribution System, DS) connecting the plurality of access points (AP-1 and AP-2).

A Station (STA) is a predetermined device including a medium access control (Medium Access Control, MAC) compliant with the specifications of the IEEE 802.11 standard and a Physical Layer (Physical Layer) interface for wireless media, and broadly includes both a non-access point (non-AP) Station and an Access Point (AP). Further, in this specification, the term "terminal" may be used to refer to either a non-AP STA or an AP, or both. A station for wireless communication comprises a processor and a communication unit, and may further comprise a user interface unit and a display unit according to an embodiment. The processor may generate a frame to be transmitted via the wireless network or process a frame received via the wireless network, and further, perform various processes for controlling the station. Further, the communication unit is functionally connected to the processor and transmits and receives frames via a wireless network for the station. According to the present invention, a terminal may be used as a term including a terminal (UE).

An Access Point (AP) is an entity that provides Access to a Distributed System (DS) via a wireless medium for stations associated therewith. In an infrastructure BSS, communication among non-AP stations is performed in principle via an AP, but even allows direct communication among non-AP stations when the direct link is configured. Meanwhile, in the present invention, an AP is used as a concept including a personal BSS coordination point (Personal BSS Coordination Point, PCP), and may broadly include a concept including a central controller, a Base Station (BS), a node B, a Base transceiver system (Base Transceiver System, BTS), or a Station controller. In the present invention, an AP may also be referred to as a base station wireless communication terminal. Base station wireless communication terminals may be used as a broad term including AP, base station (base station), enode B (eNodeB, eNB) and Transmission Point (TP). In addition, the base station wireless communication terminal may include various types of wireless communication terminals that allocate communication medium (medium) resources and perform scheduling (scheduling) in communication with a plurality of wireless communication terminals.

Multiple infrastructure BSSs may be interconnected via a Distributed System (DS). In this case, the plurality of BSSs connected via the distributed system are referred to as an extended service set (Extended Service Set, ESS).

Fig. 2 illustrates an independent BSS, which is a wireless LAN system, according to another embodiment of the present invention. In the embodiment of fig. 2, the duplicate explanation of the same as fig. 1 or of the parts corresponding to the embodiment of fig. 1 will be omitted.

Since the BSS3 illustrated in fig. 2 is an independent BSS and does not include an AP, all stations STA6 and STA7 are not connected with the AP. An independent BSS is not allowed to access the distributed system and forms a self-contained network (self-contained network). In an independent BSS, the respective stations STA6 and STA7 may be directly connected to each other.

Fig. 3 illustrates a block diagram of a configuration of a station 100 according to an embodiment of the present invention. As illustrated in fig. 3, a 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.

First, the communication unit 120 transmits and receives wireless signals, such as wireless LAN packets, and the like, and may be embedded in the station 100 or provided as a peripheral. According to an embodiment, the communication unit 120 may comprise at least one communication module using different frequency bands. For example, the communication unit 120 may include communication modules having different frequency bands (such as 2.4GHz, 5GHz, 6GHz, and 60 GHz). According to an embodiment, station 100 may include a communication module using a frequency band of 7.125GHz or more and a communication module using a frequency band of 7.125GHz or less. Each communication module may perform wireless communication with an AP or an external station according to a wireless LAN standard of a frequency band supported by the corresponding communication module. The communication unit 120 may operate only one communication module at a time or a plurality of communication modules together at the same time, depending on the capabilities and requirements of the station 100. When station 100 includes a plurality of communication modules, each communication module may be implemented by a separate element, or the plurality of modules may be integrated into one chip. In an embodiment of the present invention, the communication unit 120 may represent an RF communication module for processing Radio Frequency (RF) signals.

Next, the user interface unit 140 includes various types of input/output devices provided in the station 100. That is, the user interface unit 140 may receive user inputs by using various input devices, and the processor 110 may control the station 100 based on the received user inputs. Further, the user interface unit 140 may perform output based on a command of the processor 110 by using various output devices.

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

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

The station 100 illustrated in fig. 3 is a block diagram according to an embodiment of the invention, where separate blocks are illustrated as elements of logically distinct devices. Thus, the elements of the device may be mounted in a single chip or multiple chips depending on the design of the device. For example, the processor 110 and the communication unit 120 may be implemented when integrated as a single chip, or implemented as separate chips. Furthermore, in an embodiment of the present invention, certain components of the station 100, such as the user interface unit 140 and the display unit 150, etc., may be selectively provided in the station 100.

Fig. 4 illustrates a block diagram of a configuration of an AP 200 according to an embodiment of the present invention. As illustrated in fig. 4, an AP 200 according to an embodiment of the present invention may include a processor 210, a communication unit 220, and a memory 260. In fig. 4, among the components of the AP 200, the duplicate explanation of the same as the components of the station 100 of fig. 2 or the parts corresponding to the components of the station 100 of fig. 2 will be omitted.

Referring to fig. 4, an AP 200 according to the present invention includes a communication unit 220 operating a BSS in at least one frequency band. As illustrated in the embodiment of fig. 3, the communication unit 220 of the AP 200 may also include a plurality of communication modules using different frequency bands. That is, the AP 200 according to an embodiment of the present invention may include two or more communication modules in different frequency bands (e.g., 2.4GHz, 5GHz, 6GHz, and 60 GHz) together. Preferably, the AP 200 may include a communication module using a frequency band of 7.125GHz or more, and a communication module using a frequency band of 7.125GHz or less. Each communication module may perform wireless communication with a station according to a wireless LAN standard of a frequency band supported by the corresponding communication module. The communication unit 220 may operate only one communication module at a time or simultaneously operate a plurality of communication modules together according to the performance and requirements of the AP 200. In an embodiment of the present invention, the communication unit 220 may represent a Radio Frequency (RF) communication module for processing an RF signal.

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

Fig. 5 is a diagram schematically illustrating a procedure in which a STA sets up a link with an AP.

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

The STA 100 that successfully receives the wireless access information in the scanning step performs the authentication step by transmitting an authentication request (authentication request) (S107 a) and receiving an authentication response (authentication response) from the AP 200 (S107 b). After performing the authentication step, the STA 100 performs the association step by transmitting an association request (association request) (S109 a) and receiving an association response (association response) from the AP 200 (S109 b). In this specification, association basically refers to wireless association, but the present invention is not limited thereto, and association may broadly include both wireless association and wired association.

Meanwhile, an authentication step (S111) based on 802.1X and an IP address acquisition step (S113) via DHCP may be additionally performed. In fig. 5, the authentication server 300 is a server that handles 802.1X-based authentication of the STA 100, and may exist in physical association with the AP 200, or exist as a separate server.

Fig. 6 is a diagram illustrating a carrier sense multiple access (Carrier Sense Multiple Access, CSMA)/collision avoidance (Collision Avoidance, CA) method used in wireless LAN communication.

A terminal performing wireless LAN communication confirms whether a channel is in a busy state (busy) by performing carrier sensing before transmitting data. When a wireless signal having a preset intensity or more is sensed, a corresponding channel is determined to be in an occupied state (busy) and a terminal delays access to the corresponding channel. This procedure is referred to as clear channel assessment (Clear Channel Assessment, CCA), and the level of deciding whether a corresponding signal is sensed is referred to as a CCA threshold (CCA threshold). When a terminal receives a wireless signal having a CCA threshold or higher, the terminal instructs the corresponding terminal as a receiver, the terminal processes the received wireless signal. Meanwhile, when no wireless signal is detected or a wireless signal having a strength less than the CCA threshold is detected in the corresponding channel, it is determined that the channel is in an idle state (idle).

When it is determined that the channel is idle, each terminal having data to be transmitted performs a backoff procedure after an inter-frame space (Inter Frame Space, IFS) time, which depends on the condition of each terminal, for example, through an Arbitration IFS (AIFS), a PCF IFS (PIFS), etc. According to this embodiment, AIFS may be used as a component to replace existing DCF IFS (DIFS). Each terminal waits while reducing a slot time as long as a random number (random number) determined by the corresponding terminal during an interval (interval) of an idle state of a channel, and the terminal that completely exhausts the slot time attempts to access the corresponding channel. Thus, an interval in which each terminal performs the backoff procedure is referred to as a contention window interval.

When a particular terminal succeeds in channel access, the corresponding terminal may transmit data through the channel. However, when a terminal attempting access collides with another terminal, terminals that collide with each other are respectively assigned new random numbers to perform the backoff process again. According to an embodiment, the random number newly allocated to each terminal may be determined within a range (2×cw) that is twice the range (contention window CW) of the random number previously allocated to the corresponding terminal. Meanwhile, each terminal attempts access by performing a backoff procedure again in the next contention window interval, and in this case, each terminal performs the backoff procedure starting from the time slot time remaining in the previous contention window interval. In this way, the respective terminals performing wireless LAN communication can avoid collision of the special channels with each other.

Hereinafter, in the present invention, a terminal may be referred to as a non-AP STA, an STA, a receiving device, or a transmitting device, and the present invention is not limited thereto. Further, in the present invention, an AP STA may be referred to as an AP.

< examples of various PPDU formats >

Fig. 7 illustrates an example of a format of a PLCP protocol data unit (PLCP Protocol Data Unit, PPDU) for each of various standard generations. More specifically, fig. 7 (a) illustrates an embodiment of a legacy PPDU format based on 802.11a/g, fig. 7 (b) illustrates an embodiment of a HE PPDU format based on 802.11ax, and fig. 7 (c) illustrates an embodiment of a non-legacy PPDU (i.e., EHT PPDU) format based on 802.11 be. Fig. 7 (d) illustrates detailed field configurations of the RL-SIG and the L-SIG commonly used in the PPDU format.

Referring to fig. 7 (a), the preamble of the legacy PPDU includes a legacy short training field (Legacy Short Training field, L-STF), a legacy long training field (Legacy Long Training field, L-LTF), and a legacy signal field (Legacy Signal field, L-SIG). In embodiments of the invention, the L-STF, L-LTF, and L-SIG may be referred to as legacy preambles.

Ext> referringext> toext> fig.ext> 7ext> (ext> bext>)ext>,ext> theext> preambleext> ofext> theext> HEext> PPDUext> furtherext> includesext> aext> repetitionext> conventionalext> shortext> trainingext> fieldext> (ext> Repeatedext> Legacyext> Shortext> Trainingext> fieldext>,ext> RLext> -ext> SIGext>)ext>,ext> aext> highext> efficiencyext> signalext> aext> fieldext> (ext> Highext> Efficiencyext> Signalext> Aext> fieldext>,ext> HEext> -ext> SIGext> -ext> aext>)ext>,ext> aext> highext> efficiencyext> signalext> bext> fieldext> (ext> Highext> Efficiencyext> Signalext> Bext> fieldext>,ext> HEext> -ext> SIGext> -ext> bext>)ext>,ext> aext> highext> efficiencyext> shortext> trainingext> fieldext> (ext> Highext> Efficiencyext> Shortext> Trainingext> fieldext>,ext> HEext> -ext> stfext>)ext>,ext> andext> aext> highext> efficiencyext> longext> trainingext> fieldext> (ext> Highext> Efficiencyext> Longext> Trainingext> fieldext>,ext> HEext> -ext> ltfext>)ext> inext> theext> conventionalext> preambleext>.ext> In embodiments of the invention, the RL-SIG, HE-SIG-A, HE-SIG-B, HE-STF, and HE-LTF may be referred to as HE preambles. The detailed configuration of the HE preamble may be modified according to the HE PPDU format. For example, the HE-SIG-B may be used only in the HE MU PPDU format.

Ext> referringext> toext> fig.ext> 7ext> (ext> cext>)ext>,ext> theext> EHText> PPDUext> furtherext> includesext> repeatedext> conventionalext> shortext> trainingext> fieldsext> (ext> Repeatedext> Legacyext> Shortext> Trainingext> fieldext>,ext> RLext> -ext> SIGext>)ext>,ext> generalext> signalext> fieldsext> (ext> Universalext> Signalext> fieldext>,ext> Uext> -ext> SIGext>)ext>,ext> andext> veryext> highext> throughputext> signalext> aext> fieldsext> (ext> Extremelyext> Highext> Throughputext> Signalext> Aext> fieldext>,ext> EHText> -ext> SIGext> -ext> aext>)ext>,ext> veryext> highext> throughputext> signalext> bext> fieldsext> (ext> Extremelyext> Highext> Throughputext> Signalext> Bext> fieldext>,ext> EHText> -ext> SIGext> -ext> bext>)ext>,ext> veryext> highext> throughputext> shortext> trainingext> fieldsext> (ext> Extremelyext> Highext> Throughputext> Shortext> Trainingext> fieldext>,ext> EHText> -ext> stfext>)ext>,ext> andext> veryext> highext> throughputext> longext> trainingext> fieldsext> (ext> Extremelyext> Highext> Throughputext> Longext> Trainingext> fieldext>,ext> EHText> -ext> ltfext>)ext> inext> theext> conventionalext> preambleext>.ext> In embodiments of the invention, the RL-SIG, EHT-SIG-A, EHT-SIG-B, EHT-STF, and EHT-LTF may be referred to as EHT preambles. The specific configuration of the non-legacy preamble may be modified according to the EHT PPDU format. Ext> forext> exampleext>,ext> theext> EHText> -ext> SIGext> -ext> Aext> andext> theext> EHText> -ext> SIGext> -ext> Bext> mayext> beext> usedext> inext> onlyext> aext> portionext> ofext> theext> EHText> PPDUext> formatext>.ext>

The 64-FFT OFDM is applied to the L-SIG field included in the preamble of the PPDU, and the L-SIG field includes 64 subcarriers in total. Of the 64 subcarriers, 48 subcarriers other than the guard subcarrier, the DC subcarrier, and the pilot subcarrier are used for transmission of the L-SIG data. The modulation and coding scheme (Modulation and Coding Scheme, MCS) of BPSK and code rate=1/2 is applied in the L-SIG, and thus the L-SIG may include a total of 24 bits of information. Fig. 7 (d) illustrates a configuration of 24-bit information of the L-SIG.

Referring to fig. 7 (d), the L-SIG includes an l_rate field and an l_length field. The l_rate field includes 4 bits and indicates an MCS for data transmission. Specifically, the l_rate field indicates one value of the transmission RATE of 6/9/12/18/24/36/48/54Mbps obtained by combining a modulation scheme of BPSK/QPSK/16-QAM/64-QAM or the like with inefficiency such as 1/2, 2/3, 3/4 or the like. The total LENGTH of the corresponding PPDU may be indicated by combining information of the l_rate field and information of the l_length field. In the non-legacy PPDU format, the l_rate field is configured to a minimum RATE of 6 Mbps.

The unit of the l_length field may be allocated a total of 12 bits per byte, up to 4095 may be signaled, and the LENGTH of the corresponding PPDU may be indicated by a combination with the l_rate field. In this case, the legacy terminal and the non-legacy terminal may interpret the l_length field using different methods.

First, a method in which a legacy terminal or a non-legacy terminal analyzes the LENGTH of a corresponding PPDU using an l_length field is as follows. When the value of the l_rate field is set to indicate 6Mbps, 3 bytes (i.e., 24 bits) may be transmitted during 4us, which is one symbol duration of the 64 FFT. Therefore, 3 bytes corresponding to the SVC field and the tail field are added to the value of the field l_length, and the added value is divided by 3 bytes which are the transmission amount of one symbol, thereby obtaining the number of 64 FFT-based symbols after the L-SIG. The obtained number of symbols is multiplied by 4us (i.e., the length of one symbol), and then the time required for transmission of the L-STF, the L-LTF, and the L-SIG is added by 20us, thereby obtaining the length of the corresponding PPDU, i.e., the reception time RXTIME. This can be expressed by the following equation 1.

[ equation 1]

In this case the number of the elements to be formed is,representing a minimum natural number greater than or equal to x. Since the maximum value of the l_length field is 4095, the LENGTH of the PPDU can be set to be as long as 5.464ms. The non-legacy terminal transmitting the PPDU should set the l_length field as shown in equation 2 below.

[ equation 2]

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

[ equation 3]

TXTIME(us)＝T _L-STF +T _L-LTF +T _L-SLG +T _RL-SIG +T _U-SIG +(T _EHT-SIG-A )+(T _EHT-SIG-B )+T _EHT-STF +N _EHT-LTF ·T _EHT-LTF +T _DATA

Referring to the above equation, the LENGTH of the PPDU is calculated based on the round-up value of l_length/3. Thus, for a random value of k, three different values of l_length= {3k+1,3k+2,3 (k+1) } indicate the same PPDU LENGTH.

Referring to (e) of fig. 7, a common SIG (U-SIG) field continues to exist in EHT PPDUs and wireless LAN PPDUs of the subsequent generation, and is used to classify the generation of PPDUs including 11 be. The U-SIG is a 64 FFT-based OFDM 2 symbol, and can transmit 52 bits of information in total. Of the 52 bits, 43 bits other than the CRC/tail 9 bits are mainly divided into a version independent (Version Independent, VI) field and a version dependent (Version Dependent, VD) field.

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

The VD field is signaling information useful only for an 11be version of the PPDU, and may include a field commonly used in any PPDU format such as PPDU format and BW, and a field differently defined for each PPDU format. The PPDU format is a classifier that classifies EHT Single User (SU), EHT Multi User (MU), EHT based on Trigger (TB), EHT Extended Range (ER) PPDUs, and the like. The BW field signals five basic PPDU BW options (BW, which may be expressed in an exponent power type of 20 x 2, which may be referred to as basic BW) of 20, 40, 80, 160 (80+80), and 320 (160+160) MHz, and various remaining PPDUs BW configured via preamble puncturing (Preamble Puncturing). After signaling at 320MHz, signaling may be performed in some 80MHz punctured types. The punctured and modified channel type may be signaled directly in the BW field or may be signaled using the BW field and a field that occurs after the BW field (e.g., a field within the EHT-SIG field). If the BW field is configured to 3 bits, a total of 8 BW signaling may be performed, and thus only up to 3 signaling may be performed in the puncturing pattern. If the BW field is configured to 4 bits, a total of 16 BW signaling may be performed, and thus up to 11 signaling may be performed in the puncturing pattern.

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

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

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

In the case of SU PPDUs, multiple RUs may be allocated to STAs, and may be contiguous or non-contiguous. If the RUs allocated to the STA are discontinuous, the STA should identify the middle punctured RU in order to effectively receive the SU PPDU. Accordingly, the AP may transmit a SU PPDU including information of a punctured RU among RUs allocated to the STA (e.g., a puncturing pattern of the RU, etc.). That is, in case of the SU PPDU, a puncturing pattern field including information indicating a puncturing pattern and whether or not the puncturing pattern is applied in a bitmap format or the like may be included in the EHT-SIG field, and the puncturing pattern field may signal a discontinuous channel type occurring within the bandwidth.

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

To reduce the signaling overhead of the SU PPDU, only a limited discontinuous channel type is signaled. Puncturing may be performed for each 20MHz subchannel so that if puncturing is performed for BW with a large number of 20MHz subchannels, such as 80, 160 and 320MHz, then in the case of 320MHz, the type of discontinuous channel (if puncturing for only the edge 20MHz is also considered discontinuous) should be signaled by indicating whether each of the remaining 15 20MHz subchannels is used after the primary channel is excluded. Thus, the discontinuous channel type of allocating 15 bits to signal a single user transmission may act as excessive signaling overhead in consideration of the low transmission rate of the signaling portion.

The present invention proposes a technique for signaling the discontinuous channel type of the SU PPDU and illustrates the discontinuous channel type determined according to the proposed technique. The present invention also proposes a technique for signaling each of the Primary (Primary) 160MHz and Secondary (Secondary) 160MHz puncture types in a 320MHz BW configuration of a SU PPDU.

Further, a technique of differently configuring a PPDU indicated by a preamble puncture BW value according to a PPDU format signaled in a PPDU format field is proposed in an embodiment of the present invention. Ext>ext> assumingext>ext> thatext>ext> theext>ext> BWext>ext> fieldext>ext> isext>ext> 4ext>ext> bitsext>ext>,ext>ext> andext>ext> inext>ext> theext>ext> caseext>ext> ofext>ext> anext>ext> EHText>ext> SUext>ext> PPDUext>ext> orext>ext> TBext>ext> PPDUext>ext>,ext>ext> anext>ext> EHText>ext> -ext>ext> SIGext>ext> -ext>ext> aext>ext> ofext>ext> 1ext>ext> symbolext>ext> mayext>ext> beext>ext> additionallyext>ext> signaledext>ext> afterext>ext> theext>ext> Uext>ext> -ext>ext> SIGext>ext> orext>ext> notext>ext> signaledext>ext> atext>ext> allext>ext>,ext>ext> soext>ext> itext>ext> isext>ext> necessaryext>ext> toext>ext> completelyext>ext> signalext>ext> upext>ext> toext>ext> 11ext>ext> puncturingext>ext> patternsext>ext> onlyext>ext> viaext>ext> theext>ext> BWext>ext> fieldext>ext> ofext>ext> theext>ext> Uext>ext> -ext>ext> SIGext>ext> inext>ext> viewext>ext> ofext>ext> thisext>ext>.ext>ext> However, in the case of the EHT MU PPDU, the EHT-SIG-B is additionally signaled after the U-SIG, so that up to 11 puncturing patterns can be signaled in a different method from that of the SU PPDU. In the case of an EHT ER PPDU, the BW field may be configured to be 1 bit to signal whether the EHT ER PPDU uses a 20MHz band or a 10MHz band PPDU.

Fig. 7 (f) illustrates a configuration of a Format specific (Format-specific) field of the VD field when an EHT MU PPDU is indicated in a PPDU Format field of the U-SIG. Ext> inext> theext> caseext> ofext> MUext> PPDUsext>,ext> SIGext> -ext> Bext> isext> necessarilyext> requiredext>,ext> whichext> isext> aext> signalingext> fieldext> forext> simultaneousext> receptionext> byext> multipleext> usersext>,ext> andext> SIGext> -ext> Bext> mayext> beext> transmittedext> afterext> Uext> -ext> SIGext> withoutext> separateext> SIGext> -ext> aext>.ext> For this purpose, the information for decoding SIG-B should be signaled in the U-SIG. These fields include the SIG-B MCS, SIG-B DCM, the number of SIG-B symbols, SIG-B compression, the number of EHT-LTF symbols, etc.

Referring to fig. 8, the PPDU may include a preamble (preamble) and a data portion, and may be classified into an EHT PPDU format as a PPDU type according to a U-SIG field included in the preamble. Specifically, based on a PPDU format field included in the U-SIG field, it may be indicated whether the format of the PPDU is an EHT PPDU.

Fig. 8 (a) illustrates an example of an EHT SU PPDU format for a single STA. Ext> theext> EHText> SUext> PPDUext> isext> aext> PPDUext> forext> Singleext> Userext> (ext> SUext>)ext> transmissionext> betweenext> anext> APext> andext> aext> Singleext> STAext>,ext> andext> anext> EHText> -ext> SIGext> -ext> aext> fieldext> forext> additionalext> signalingext> mayext> beext> locatedext> afterext> theext> uext> -ext> SIGext> fieldext>.ext>

Fig. 8 (b) illustrates an example of an EHT trigger-based PPDU format corresponding to an EHT PPDU transmitted based on a trigger frame. The EHT trigger-based PPDU is an EHT PPDU based on trigger frame transmission and is an uplink PPDU for a response to a trigger frame. Ext> unlikeext> theext> EHText> SUext> PPDUext>,ext> theext> EHText> -ext> SIGext> -ext> Aext> fieldext> isext> notext> locatedext> afterext> theext> Uext> -ext> SIGext> fieldext> inext> theext> EHText> PPDUext>.ext>

Fig. 8 (c) illustrates an example of an EHT MU PPDU format corresponding to EHT PPDUs of a plurality of users. An EHT MU PPDU is a PPDU used to transmit a PPDU to one or more STAs. In the EHT MU PPDU format, the HE-SIG-B field may be located after the U-SIG field.

Fig. 8 (d) illustrates an example of an EHT ER SU PPDU format for single user transmission with STAs within an extended range. In comparison with the EHT SU PPDU illustrated in (a) of fig. 8, 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 relocated on the time axis.

The EHT MU PPDU illustrated in (c) of fig. 8 may be used by the AP to perform downlink transmission toward a plurality of STAs. Here, the EHT MU PPDU may include scheduling information such that a plurality of STAs may simultaneously receive PPDUs transmitted from the AP. The EHT MU PPDU may transmit AID information of a transmitter and/or a receiver of the PPDU transmitted via a user specific (user specific) field of the EHT-SIG-B to the STA. Accordingly, a plurality of terminals having received the EHT MU PPDU may perform a spatial reuse (spatial reuse) operation based on AID information of a user-specific field included in a preamble of the received PPDU.

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

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

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

Further, part of fields or part of information of fields in the fields illustrated in fig. 8 may be omitted, and a case where part of fields or part of information of fields is omitted may be defined as a compressed mode (compressed mode) or a compressed mode (compressed mode).

Referring to fig. 9, a concept of a device (device) to which one or more STAs are affiliated (affile) may be defined. As another embodiment, according to an embodiment of the present invention, a device to which more than one (i.e., more than two) STAs are affiliated may be defined. In this case, the device may be a logical (logical) concept. Thus, a device to which one or more STAs having such a concept depend may be referred to as a multi-link device (MLD), a multi-band device, or a multi-link logical entity (multi-link logical entity: MLLE).

Alternatively, the apparatus of the above concept may be referred to as a multi-link entity (MLE). In addition, the MLD may have one MAC SAP (media access control service access point; medium access control service access point) to LLC (logical Link control; logical link control), and the MLD may have one MAC data service.

STAs included in the MLD may operate on one or more links or channels (channels). That is, STAs included in the MLD may operate on different multiple channels. For example, STAs included in the MLD may operate using channels of different frequency bands of 2.4GHz, 5GHz, 6 GHz. Thus, MLD may gain benefits in channel access (channel access) and may improve the performance of the overall network. The wireless LAN of the related art operates on a single link (single link), but the MLD operation may obtain more channel access opportunities by using multiple links, or the STA may operate efficiently on multiple links in consideration of channel states.

Further, when the STA subordinate to the MLD is an AP, the MLD to which the AP is subordinate may be an AP MLD. However, when an STA subordinate to the MLD is a non-AP STA, the MLD to which the non-AP is subordinate may be a non-AP MLD.

Further, an AP Multi-link Device (MLD) may be a Device including one or more wireless Access Points (APs), or may be a Device connected to an upper layer through one interface. That is, the AP MLD may be connected to the logical link control (Logical Link Control, LLC) layer through one interface. Multiple APs included in the AP MLD may share some functions in the MAC layer. Each AP in the AP MLD may operate on a different link. The STA MLD may be a device including one or more non-AP STAs, or may be a device connected to an upper layer through one interface.

That is, the STA MLD may be connected to the LLC layer through one interface. Multiple STAs included in the STA MLD may share some functions in the MAC layer. In addition, the STA MLD may be referred to as a non-AP MLD. In this case, the AP MLD and the STA MLD may perform a multilink operation for communication using a plurality of individual links. That is, when the AP MLD includes a plurality of APs, each AP may configure a separate link and perform a transceiving operation of frames with each terminal included in the STA MLD using the plurality of links. In this case, each link may operate in a 2.4GHz, 5GHz, or 6GHz band, and a bandwidth extension operation may be performed on each link. For example, when the AP MLD establishes one link in the 2.4GHz band and two links in the 5GHz band, the AP MLD may perform frame transmission with a bandwidth of 40MHz through a bandwidth extension scheme in the 2.4GHz band, and in each link using the 5GHz band, the AP MLD may perform frame transmission with a bandwidth of 320MHz at maximum by using a discontinuous bandwidth.

In addition, the AP MLD or the STA MLD may not perform a reception operation by another terminal similar during a transmission operation performed by one terminal in the MLD due to an interference problem inside the device. As described above, when one AP or terminal in the MLD performs a transmitting operation, an operation in which the other AP or terminal in the MLD performs a receiving is referred to as simultaneous transmitting and receiving (Simultaneous Transimit and Receive, STR). The AP MLD may perform STR operations for all links. Alternatively, in some links of the AP MLD, STR operation may not be possible. A terminal MLD that can perform STR operation can access an AP MLD, and an MLD that cannot perform STR operation for part or all of links can access the AP MLD. In addition, terminals not belonging to the MLD (e.g., ieee802.11a/b/g/n/ac/ax terminals) may additionally access APs included in the AP MLD.

The AP MLD and the STA MLD may perform a negotiation process for multi-link use in the scanning and access process shown in fig. 5. For example, in the scanning process shown in fig. 5, an AP included in the AP MLD may transmit a beacon frame including an indicator indicating that a multilink operation is available, the number of available links, and information of a plurality of available links. In addition, the terminal belonging to the STA MLD may transmit a probe request frame including an indicator indicating that the multilink operation is available, and the AP belonging to the AP MLD may transmit a probe response frame including an indicator indicating that the multilink operation is available. In this case, the AP may additionally transmit including the number of links available during the multi-link operation, link information, and the like.

In the scanning process, the STA MLD, which has checked the multi-link operation of the AP MLD and used the link information, may perform an access procedure with the AP MLD. In this case, the AP MLD and the STA MLD may start a negotiation procedure for the multi-link operation. The negotiation process for the multi-link operation may be performed in an access process between the AP belonging to the AP MLD and the STA belonging to the STA MLD. That is, an arbitrary terminal (e.g., STA 1) belonging to the STA MLD may transmit an access request frame to an arbitrary AP (e.g., AP 1) belonging to the AP MLD to transmit an indicator indicating that the multilink operation of the terminal is available and a request indicator requesting to perform the multilink operation. An AP that receives the access request frame from the STA may check an indicator for requesting the multi-link operation, and if the AP is capable of performing the multi-link operation, the AP may transmit an access response frame for allowing the multi-link operation, including link information to be used for the multi-link operation, parameters for each link, and the like, to the corresponding terminal. Parameters for multilink operation may include one or more of the frequency band of each link used, the bandwidth extension direction, the target beacon transmission time (Target Beacon Transmission Time, TBTT), whether to perform STR operation. The AP MLD and the STA MLD, which confirm the use of the multi-link operation by exchanging the access request frame and the response frame, may perform the frame transmission operation using the plurality of links using the plurality of APs included in the AP MLD and the plurality of terminals included in the STA MLD after responding to the access procedure.

Referring to fig. 9, there may be an MLD including a plurality of STAs, and the plurality of STAs included in the MLD may operate on a plurality of links. In fig. 9, an MLD including an AP (i.e., AP1, AP2, and AP 3) may be referred to as an AP MLD, and an MLD including a non-AP STA (i.e., non-AP STA 1, non-AP STA 2, and non-AP STA 3) may be referred to as a non-AP MLD. STAs included in the MLD may operate on Link1 (Link 1), link2 (Link 2), link3 (Link 3), or some of links 1 to 3.

According to an embodiment of the present invention, the multilink operation may include a multilink setup (multilink setup) operation. The multilink setting operation may correspond to association (association) performed in a single link operation. To exchange frames among multiple links, the multiple links may be set first. The multilink setup operation may be performed using a multilink setup element (multi-link setup element). In this case, the multilink setting element may include capability information (capability information) related to the multilink, and the capability information may include information about frames that another STA included in the MLD may transmit through another link while the STA included in the MLD receives the frames through the certain link. That is, the capability information may include information about whether an STA (non-AP STA) and/or an AP (or AP STA) can simultaneously transmit/receive frames in different transmission directions through links included in the MLD. In addition, the capability information may also include information about available links or operating channels (operating channel). The multilink setting may be set through negotiation (registration) between peer STAs (peer STAs), and the multilink operation may be set through one link.

According to an embodiment of the present invention, there may be a mapping relationship between TID and MLD links. For example, when a TID and a link are mapped, the TID may be sent over the mapped link. The mapping between TID and link may be implemented based on the transmission direction (direct-based). For example, the mapping may be implemented for two directions between MLD1 and MLD2, respectively. In addition, the mapping between TID and link may have default settings. For example, the mapping between TIDs and links may be such that substantially all TIDs are mapped to a link.

Fig. 10 is a diagram illustrating an example of a TID-to-link mapping method according to an embodiment of the invention.

Referring to fig. 10, as described with reference to fig. 9, there may be a mapping relationship between TID and links. Further, in the present invention, the mapping relationship between TID and link may be referred to as TID-to-link mapping, TID mapping, link mapping, etc. The TID may be a traffic identifier (traffic identifier). Further, the TID may be an Identifier (ID) for classifying traffic, data, etc. to support quality of service (QoS).

Further, the TID may be an ID used or assigned in a layer higher than the MAC layer. TID may represent Traffic Class (TC) and Traffic Stream (TS). Further, TID may be 16 values, which may be represented by a value from 0 to 15, for example. In addition, different TID values may be used depending on access policies, channel access, and medium access methods. For example, when EDCA (hybrid synergy function (HCF) contention-based channel access, enhanced distributed channel access) is used, the possible TID value may be 0 to 7. Further, in the case of EDCA, the TID value may indicate User Priority (UP), and the UP may be a value regarding TC or TS. Further, UP may be a value allocated in a higher layer than MAC. Further, when HCCA (HCF controlled channel access) or SPCA is used, possible TID values may be 8 to 15. Further, when HCCA or SPCA is used, TID may indicate TSID. Further, when HEMM or SEMM is used, the TID value may be 8 to 15. Furthermore, when HEMM or SEMM is used, TID may represent TSID.

Furthermore, there may be a mapping relationship between UP and Access Category (AC). The AC may be a tag indicating a QoS for providing in EDCA or a tag indicating a set of EDCA parameters. EDCA parameters or a set of EDCA parameters may be used for channel access. The AC may be used by QoS STAs.

The AC value may BE set to one of ac_bk, ac_be, ac_vi, and ac_vo. Ac_bk, ac_be, ac_vi, and ac_vo may represent background, best effort (best effort), video, and voice, respectively. In addition, ac_bk, ac_be, ac_vi, and ac_vo may BE subdivided. For example, ac_vi may be subdivided into a primary ac_vi and a backup ac_vi. In addition, ac_vo can be subdivided into a main ac_vo and a standby ac_vo. Further, the UP value or TID value may be mapped to the AC value. For example, the UP or TID values 1, 2, 0, 3, 4, 5, 6, 7 may BE mapped to AC_BK, AC_BE, AC_VI, AC_VO, respectively. Alternatively, the UP or TID values 1, 2, 0, 3, 4, 5, 6, 7 may BE mapped to AC_BK, AC_BE, backup AC_VI, primary AC_VO, backup AC_VO, respectively. Further, the UP value or TID value 1, 2, 0, 3, 4, 5, 6, and 7 may have priority that becomes higher in order. That is, "1" may be of low priority, while "7" may be of high priority. Accordingly, the priority may BE increased in the order of ac_bk, ac_be, ac_vi, and ac_vo. In addition, ac_bk, ac_be, ac_vi, and ac_vo may correspond to AC indexes (ACI) 0, 1, 2, and 3, respectively.

Thus, there may be a relationship between TID and AC. Therefore, the TID-to-link mapping of the present invention may also be a mapping relationship between ACs and links. Furthermore, in the present invention, "TID mapped" may mean AC mapped and vice versa.

According to an embodiment of the invention, there may be a TID mapped to each of the multiple links. For example, there may be a mapping as to on which of a plurality of links a particular TID or a particular AC is allowed to transmit and receive. Furthermore, such a mapping may be defined separately for each of the two directions of the link. Further, as described above, the mapping between TID and link may have a default (default) configuration. For example, the mapping between TIDs and links may be such that substantially all TIDs are mapped to a link. Furthermore, according to an embodiment, at a particular point in time, a certain TID or a certain AC may be mapped to at least one link. In addition, management frames or control frames may be sent on all links.

In the present invention, a data frame corresponding to TID or AC mapped for a specific direction of a link may be transmitted. Further, a data frame corresponding to TID or AC that is not mapped for a specific direction of the link cannot be transmitted.

According to an embodiment, the TID-to-link mapping may also be applied to acknowledgements (acknowledgements). For example, the block acknowledgement protocol (block ack agreement) may be based on TID-to-link mapping. Alternatively, the TID-to-link mapping may be based on a block acknowledgement protocol. For example, there may be a block acknowledgement protocol for TID of TID-to-link mapping.

QoS services may be provided through TID-to-link mapping. For example, data of the corresponding AC, TID is quickly transmitted by mapping the AC, TID with high priority to links with good channel state or with fewer STAs. Alternatively, through TID-to-link mapping, STAs of a particular link may be enabled to save power (or may enter a doze state).

Referring to fig. 10, there may be an AP MLD including AP1 and AP 2. In addition, there may be a non-AP MLD including STA 1 and STA 2. Further, link 1 and link 2, which are a plurality of links, may exist in the AP MLD. AP1 and STA 1 may be associated in link 1 and AP2 and STA 2 may be associated in link 2.

Thus, link 1 may comprise a link from AP1 to STA 1 and/or a link from STA 1 to AP1, and link 2 may comprise a link from AP2 to STA 2 and/or a link from STA 2 to AP 2. In this case, TIDs and/or ACs may be mapped to each link.

For example, all TIDs and all ACs may be mapped to links from AP1 to STA 1 in link 1 and links from STA 1 to AP1 in link 1. In addition, only ac_vo or TID corresponding to ac_vo may be mapped to a link transmitted from STA 2 to AP2 among links 2. Furthermore, only the mapped TID and/or AC data may be transmitted over the corresponding link. Furthermore, data of TID or AC that is not mapped to a link cannot be transmitted on the corresponding link.

Simultaneous Transmit and Receive (STR) operations, which are simultaneously transmitted or received by the MLD, may be limited and may be associated with frequency spacing between multiple links operating over multiple links.

Thus, according to an embodiment of the present invention, when the interval between links is m MHz, simultaneous transmission or reception is limited, and when the interval between links is n MHz (n is greater than m), simultaneous transmission or reception may not be limited. The present embodiment can solve the problem of limitation of simultaneous transmission or reception, and duplicate description can be omitted. In addition, the present embodiment can be applied to MLD that cannot STR.

According to an embodiment of the invention, the duration information may be shared between links operating over multiple links. The duration information may be TXOP duration information transmitted in a signaling field of the preamble. The signaling field may be the U-SIG field described above. Ext> alternativelyext>,ext> theext> signalingext> fieldext> mayext> beext> theext> HEext> -ext> SIGext> -ext> Aext> fieldext> describedext> aboveext>.ext> In another embodiment, the Duration information may be Duration information indicated by a Duration/ID field included in the MAC header. In another embodiment, the duration information may be duration information indicated by a length field (LLength field) included in the L-SIG field. Ext> accordingext> toext> anext> embodimentext>,ext> theext> durationext> informationext> indicatedext> byext> theext> Uext> -ext> SIGext> fieldext>,ext> theext> HEext> -ext> SIGext> -ext> aext> fieldext>,ext> orext> theext> durationext> /ext> idext> fieldext> mayext> beext> aext> valueext> indicatingext> theext> txopext> durationext>.ext> According to an embodiment, the duration information indicated by the L-SIG field may be a value indicating a length of a physical layer protocol data unit (PPDU) including the L-SIG field or indicating an end of the PPDU including the L-SIG field.

Furthermore, according to an embodiment of the present invention, transmission or channel access may be restricted during a duration based on duration information shared between links. A method of limiting transmission or channel access may include setting a NAV. Alternatively, the NAV may be reset to resume transmission or channel access. At this time, the NAV may be an intra-BSS NAV. The intra-BSS NAV may be a NAV set by an intra-BSS frame (or PPDU). That is, the STA belonging to the MLD may set the NAV based on a frame (or PPDU) directed to another STA belonging to the MLD.

According to an embodiment of the invention, there may be an inter-link NAV. In case of operation through multiple links, the inter-link NAV may be a NAV used by STAs of multiple links belonging to a specific MLD. For example, based on the inter-link NAV set according to the duration information received in link 1, data may not be transmitted on link 2. In addition, inter-link NAVs may exist or be used for MLDs that cannot STR. For example, when the inter-link NAV is set, the MLD in which the inter-link NAV is set may not perform transmission or channel access on a plurality of links (or all links used by the MLD).

Further, the type of NAV may include a basic NAV in addition to an intra-BSS NAV. The basic NAV may be a NAV set by an inter-BSS frame (or PPDU) or may be set by a frame (or PPDU) that is not determined to be intra-BSS or inter-BSS.

In the case of additionally using the inter-link NAV, there may be an advantage in updating the NAV setting, as compared to the case of not using the inter-link NAV. For example, a situation may occur in which even a NAV set through another link is reset. For example, although the inter-link NAV is set based on a specific frame (or PPDU), the set inter-link NAV may be reset when it is determined that the above-mentioned frame (or PPDU) does not point to the same MLD. If there are MLDs operating in link 1 and link 2, the NAV of link 1 may be set based on the frames received in link 1. Thereafter, the NAV of link 1 may be updated based on the frames of link 2. Further, if the NAV of the link 1 is reset when the NAV of the link 2 is not required to be maintained, NAV information set based on the frame received in the link 1 may be lost. If the inter-link NAV is used together with the NAV of each link, the NAV of each link can be maintained even when the inter-link NAV is reset, so that this problem can be solved.

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

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

Fig. 12 is a diagram illustrating another example of a multilink NAV setting operation according to another embodiment of the present invention.

Fig. 12 illustrates a detailed description of a specific method of the embodiment illustrated in fig. 11, and thus, a repetitive description will be omitted.

As described above, another STA belonging to the same MLD may stop or resume channel access or transmission based on a frame or PPDU received by the certain STA belonging to the MLD. In the present invention, stopping channel access or transmission may include setting (updating) a NAV, determining that a channel is busy, or stopping CCA. Further, resuming channel access or transmission may include resetting the NAV, canceling the NAV setting, determining that the channel is idle, or performing CCA, among other operations. Such operation may be indicated hereinafter as stopping and resuming channel access. Further, hereinafter, STA 1 and STA 2 belong to MLD, and STA 1 and STA 2 operate on link 1 and link 2, respectively. In addition, the frame and the PPDU may be mixed. Further, the NAV at this time may be an intra-BSS NAV or an inter-link NAV as described in fig. 11.

According to an embodiment of the present invention, STA 2 may discontinue channel access when STA 1 begins to receive frames. Further, STA 2 may continue to interrupt the state of channel access when STA 1 obtains duration information from the L-SIG. In this case, the state in which the STA 2 interrupts channel access may be determined until the end of the frame received by the STA 1. In addition, STA 2 may resume channel access when STA 1 does not properly decode the L-SIG (i.e., invalid L-SIG).

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

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

Alternatively, if the information obtained from the U-SIG of the frame received by STA 1 indicates that the corresponding frame is a frame that STA 1 does not receive, STA 2 may resume channel access. For example, if the PHY identifier obtained from the U-SIG is an ID corresponding to a future standard or an ID that cannot be identified, the STA 2 may resume channel access.

Ext> furtherext>,ext> althoughext> theext> caseext> ofext> receivingext> theext> Uext> -ext> SIGext> hasext> beenext> describedext>,ext> theext> sameext> embodimentext> mayext> alsoext> beext> appliedext> toext> theext> caseext> ofext> receivingext> theext> HEext> -ext> SIGext> -ext> aext> inext> theext> caseext> ofext> receivingext> theext> HEext> PPDUext>.ext> Ext> forext> exampleext>,ext> HEext> -ext> SIGext> -ext> aext> mayext> includeext> aext> txopext> durationext> andext> bssext> colorext>,ext> andext> thusext> mayext> performext> operationsext> asext> describedext> aboveext>.ext>

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

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

Further, although the case of receiving the EHT-SIG has been described, the same embodiment is also applicable to the case of receiving the HE-SIG-B in the case of receiving the HE PPDU. For example, the HE-SIG-B may include a STA-ID, and thus may perform operations as described above.

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

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

The channel access interruption and resumption described in fig. 12 may sequentially operate according to a decoding order as the reception of a frame (or PPDU) is started in the STA 1 and sequentially decoded. The decoding order may be based on PPDU format, frame format, etc. For example, decoding (in the case of an EHT PPDU) may be performed in the order of L-SIG, U-SIG, EHT-SIG, and MAC header. Ext> alternativelyext>,ext> decodingext> mayext> beext> performedext> inext> theext> orderext> ofext> theext> Lext> -ext> SIGext>,ext> HEext> -ext> SIGext> -ext> Aext>,ext> andext> MACext> headerext> (ext> inext> theext> caseext> ofext> HEext> SUext> PPDUext> andext> HEext> TBext> PPDUext>)ext>.ext> Alternatively, decoding may be performed in the order of L-SIG, HE-SIG-A, HE-SIG-B, and MAC header (in the case of HE MU PPDU). Alternatively, decoding may be performed in the order of the L-SIG and MAC header (in the case of an 11a/g PPDU).

According to an embodiment of the present invention, the STA-ID may be a value indicating an intended receiver of a PPDU or a Resource Unit (RU). Further, the STA-ID may be included in an EHT-SIG field or an HE-SIG-B field. Further, the STA-ID may indicate a value corresponding to a single STA. For example, when a plurality of STAs are included in the MLD, the STA-ID may indicate a value corresponding to one STA of the plurality of STAs. Further, the STA-ID may be a value based on the AID or MAC address of the STA.

In accordance with an embodiment of the present invention, the STA may classify (or judge) the BSS based on the received frame or the received PPDU. The classification of the BSS may include classification according to whether the received frame or the received PPDU corresponds to a BSS to which the STA performing the classification belongs. Alternatively, the classification of the BSS may refer to an operation of classifying according to whether or not a received frame or a received PPDU is transmitted from the BSS to which the STA performing the classification belongs. Further, classifying the BSS may include an operation of classifying according to whether the received frame or the received PPDU is transmitted from a BSS to which the classified STA does not belong. Further, the classification of the BSS may include an operation of classifying according to which BSS the received frame or the received PPDU belongs to. Alternatively, the classification of BSSs may represent an operation of classifying according to which BSS the received frame or the received PPDU is transmitted from. According to an embodiment of the present invention, a BSS to which a classified STA belongs may be referred to as an intra-BSS. Alternatively, a BSS including a BSS to which the classified STA belongs may be referred to as an intra-BSS. Furthermore, BSSs that are not intra-BSS may be referred to as inter-BSSs. Alternatively, BSSs that are not intra-BSS may be BSSs or BSSs that are not classified. Alternatively, the inter-BSS may include unclassified BSSs. In addition, BSSs to which the classified STAs do not belong may be referred to as inter-BSSs.

According to an embodiment of the present invention, when it is determined that the received frame or the received PPDU corresponds to or is transmitted from within the BSS, the received frame or the received PPDU may be referred to as an intra-BSS frame or an intra-BSS PPDU, respectively. Further, when it is determined that the received frame or the received PPDU corresponds to or is transmitted from an inter-BSS, the received frame or the received PPDU may be referred to as an inter-BSS frame or an inter-BSS PPDU, respectively. Further, the PPDU including the intra-BSS frame may be an intra-BSS PPDU. Further, the PPDU including the inter-BSS frame may be an inter-BSS PPDU.

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

BSS classification conditions may include conditions based on BSS color. The BSS color may be an identifier of the BSS. Ext>ext> furtherext>ext>,ext>ext> theext>ext> BSSext>ext> colorext>ext> mayext>ext> beext>ext> includedext>ext> inext>ext> aext>ext> preambleext>ext> ofext>ext> theext>ext> PPDUext>ext>,ext>ext> moreext>ext> specificallyext>ext>,ext>ext> inext>ext> aext>ext> signalingext>ext> fieldext>ext> (ext>ext> e.g.ext>ext>,ext>ext> aext>ext> HEext>ext> -ext>ext> SIGext>ext> -ext>ext> aext>ext> fieldext>ext>,ext>ext> aext>ext> uext>ext> -ext>ext> SIGext>ext> fieldext>ext>,ext>ext> orext>ext> aext>ext> vhtext>ext> -ext>ext> SIGext>ext> -ext>ext> aext>ext> fieldext>ext>)ext>ext>.ext>ext> In addition, BSS color may be included in TXVECTOR transferred from the MAC layer to the PHY layer of the sender. In addition, BSS color may be included in RXVECTOR transferred from the PHY layer to the MAC layer of the receiver. Parameters included in TXVECTOR and RXVECTOR may be referred to as TXVECTOR parameters and RXVECTOR parameters, respectively. Furthermore, BSS colors may be included in the TXVECTOR parameter or the RXVECTOR parameter. Further, the AP may inform the STA of the BSS color set by the AP. According to an embodiment, BSSs may be classified based on BSS colors included in the received PPDUs. If the BSS color included in the PPDU received by the STA is different from the BSS color of the BSS corresponding to the STA, the received PPDU may be classified as an inter-BSS PPDU. Alternatively, if the BSS color included in the PPDU received by the STA is different from the BSS color of the BSS corresponding to the STA and the value thereof is not zero, the received PPDU may be classified as an inter-BSS PPDU. In addition, if the BSS color included in the PPDU received by the STA is the same as the BSS color of the BSS corresponding to the STA, the received PPDU may be classified as an intra-BSS PPDU.

BSS classification conditions may include conditions based on MAC addresses. The MAC address may be included in a MAC header of the frame. Further, the MAC address may include a Receiver Address (RA), a Transmitter Address (TA), a BSSID, a Source Address (SA), a Destination Address (DA), etc. According to an embodiment, BSSs may be classified based on MAC addresses included in received frames. If the MAC address included in the received frame is different from the BSSID of the BSS corresponding to the STA, the received frame may be classified as an inter-BSS PPDU. More specifically, if all MAC addresses included in the received frame are different from BSSIDs of BSSs corresponding to STAs, the received frame may be classified as an inter-BSS PPDU. Further, if the MAC address included in the received frame is the same as the BSSID of the BSS corresponding to the STA, the received frame may be classified as an intra-BSS frame. More specifically, if at least one of the MAC addresses included in the received frame is identical to the BSSID of the BSS corresponding to the STA, the received frame may be classified as an intra-BSS frame.

The corresponding BSS may include a BSS to which the STA is associated. Further, the corresponding BSS may include BSSs included in the same multiple BSSID set as the BSS with which the STA is associated. Further, the corresponding BSS may include BSSs included in the same co-supported BSSID set as the BSS with which the STA is associated. Further, information about one or more BSSs included in the same multiple BSSID set or the same co-sited BSSID set may be transmitted through one frame.

BSS classification conditions may include conditions based on values of partial AID fields included in the VHT PPDU. A partial AID field may be included in a preamble of the VHT PPDU. Ext> furtherext>,ext> aext> partialext> AIDext> fieldext> mayext> beext> includedext> inext> aext> VHText> -ext> SIGext> -ext> aext> fieldext> includedext> inext> theext> VHText> PPDUext>.ext> According to an embodiment of the present invention, the partial AID field may represent a portion of BSS color. For example, when using a partial BSS color function, the partial AID field may indicate a portion of the BSS color. Alternatively, when an AID allocation rule is used, a partial AID field may indicate a portion of BSS color. The AID allocation rule may be a method of allocating AIDs based on BSS colors. Ext> furtherext>,ext> ifext> aext> groupext> idext> fieldext> includedext> inext> aext> VHText> -ext> SIGext> -ext> aext> fieldext> ofext> theext> VHText> PPDUext> hasext> aext> presetext> valueext> (ext> e.g.ext>,ext> theext> groupext> idext> fieldext> isext> setext> toext> 63ext>)ext>,ext> theext> partialext> aidext> fieldext> mayext> indicateext> aext> portionext> ofext> bssext> colorext>.ext> According to an embodiment, when the partial AID field of the received PPDU indicates a part of the BSS color, if the value of the received partial AID field is different from a part of the BSS color corresponding to the received STA, the received PPDU may be classified as an inter-BSS PPDU.

Further, when the partial AID field of the received PPDU indicates a part of BSS color, if the received partial AID field value is equal to a part of BSS color corresponding to the received STA, the received PPDU may be classified as an intra-BSS PPDU. Further, in this case, a portion of the BSS color may be 4 LSBs of the BSS color. According to a further embodiment, the partial AID field may indicate a portion of the BSSID. Ext> forext> exampleext>,ext> ifext> aext> groupext> idext> fieldext> includedext> inext> aext> VHText> -ext> SIGext> -ext> aext> fieldext> ofext> theext> VHText> PPDUext> hasext> aext> presetext> valueext> (ext> e.g.ext>,ext> theext> groupext> idext> fieldext> isext> setext> toext> 0ext>)ext>,ext> theext> partialext> aidext> fieldext> mayext> indicateext> aext> portionext> ofext> theext> bssidext>.ext> According to an embodiment, when the partial AID field of the received PPDU indicates a part of the BSSID, if the received partial AID field value is different from a part of the BSSID corresponding to the received STA, the received PPDU may be classified as an inter-BSS PPDU. Further, when the partial AID field of the received PPDU indicates a part of the BSSID, if the received partial AID field value is equal to a part of the BSSID corresponding to the received STA, the received PPDU may be classified as an intra-BSS PPDU. Further, in this case, a portion of the BSSID may be 9 MSBs of the BSSID. Further, the PARTIAL AID field value may be included in the TXVECTOR parameter partal_aid or the RXVECTOR parameter partal_aid. In addition, the GROUP ID field value may be included in the TXVECTOR parameter group_id or the RXVECTOR parameter group_id.

The BSS classification condition may include a condition that the AP receives a PPDU satisfying a predetermined condition. For example, the PPDU of the predetermined condition may include a downlink PPDU. According to an embodiment, the downlink PPDU may include a VHT MU PPDU. Further, the downlink PPDU may include a PPDU in which signaling indicating whether it is uplink or downlink is set to a preset value. Signaling indicating whether to uplink or downlink may be included in the signaling field of the HE PPDU. Alternatively, signaling indicating whether uplink or downlink may be included in the U-SIG. The U-SIG may be included in a preamble of the EHT PPDU or a PPDU following the EHT standard.

In addition, there may be cases where it cannot be classified as an intra-BSS PPDU or an inter-BSS PPDU. For example, if the above condition classified as an intra-BSS PPDU and the condition classified as an inter-BSS PPDU are not both satisfied, the intra-BSS PPDU or the inter-BSS PPDU may not be classified.

Further, if the classification results according to the plurality of conditions are inconsistent when classifying the BSS, the final result may be determined according to a predetermined condition. For example, when the result according to the BSS color-based condition is inconsistent with the result according to the MAC address-based condition, the result according to the MAC address-based condition may be prioritized or the final result may be determined as the result according to the MAC address-based condition. Alternatively, if both the condition classified as an intra-BSS PPDU and the condition classified as an inter-BSS PPDU are satisfied, they may be classified as an intra-BSS PPDU.

According to an embodiment of the present invention, the STA may perform the operation of the class-based BSS. The operation of the class-based BSS may include a power saving operation within the PPDU. The power saving operation within the PPDU may be a power saving operation based on the received PPDU. When a predetermined condition is satisfied, a power saving operation within the PPDU may be performed. The predetermined condition may include a condition to classify the received PPDU as an intra-BSS PPDU. Further, the predetermined condition may include a condition in which the forced receiver of the received PPDU is not an STA that receives the PPDU. For example, if an ID or address included in the PPDU does not correspond to an STA that receives the PPDU, the forced receiver of the PPDU may not correspond to an STA that receives the PPDU. The ID may be included in a preamble of the PPDU. For example, the ID may be an sta_id included in a preamble of the PPDU. In addition, the sta_id may be included in the HE MU PPDU or the EHT PPDU. Further, the address may be the MAC address described above. Further, when the signaling included in the received PPDU indicates uplink or downlink, the forced receiver of the PPDU may not be the STA that receives the PPDU. Further, when an STA receiving the PPDU is configured not to support the configuration of the received PPDU, the forced receiver of the PPDU may not be the STA receiving the PPDU. The configuration of the received PPDU may include MCS, number of spatial streams, channel width, etc. of the PPDU. In addition, if the STA receiving the PPDU does not support the configuration of the received PPDU, a PHY-rxend. In addition, if the received PPDU has a preset format, the mandatory receiver of the PPDU may not be the STA that receives the PPDU. The predetermined format may include a TB PPDU. The TB PPDU may include a HE TB PPDU and an EHT TB PPDU. Further, the TB PPDU may be a PPDU transmitted in response to a triggered frame. The triggered frames may include triggered frames. The triggered frames may include frames containing trigger information. The trigger information may be included in a MAC header (e.g., an a-control field). Further, the trigger information or information included in the trigger frame may include a length of the response PPDU, RU to be used in response, PHY configuration to be used in response, MAC configuration, and the like. The intra-PPDU power saving operation may be an operation of entering a doze state until the end of the received PPDU. In another embodiment, the reception or decoding of the PPDU or frame may be interrupted when the STA determines that the forced receiver of the received PPDU or frame is not the STA.

The operation of the class-based BSS may include an operation of setting (or updating) a NAV. According to an embodiment, the STA may operate one or more NAVs. Further, when the STA receives the PPDU or frame, the STA may set a NAV corresponding to the classified BSS based on the received PPDU or frame. For example, the intra-BSS NAV may be a NAV corresponding to an intra-BSS PPDU. Further, the basic NAV may be a NAV corresponding to a PPDU other than the intra-BSS PPDU. Alternatively, the basic NAV may be a NAV corresponding to an inter-BSS PPDU. Further, when the NAV is set based on the received PPDU or the received frame, duration information included in the received PPDU or the received frame may be used. The duration information may include a TXOP. For example, the TXOP may indicate a value included in the TXOP field. The TXOP field may be included in a preamble of the PPDU. Ext> forext> exampleext>,ext> theext> TXOPext> fieldext> mayext> beext> includedext> inext> aext> HEext> -ext> SIGext> -ext> aext> fieldext> ofext> theext> HEext> PPDUext>.ext> Alternatively, the TXOP field may be included in the EHT PPDU or a U-SIG field of a standard PPDU after the EHT. Further, duration information may be included in the MAC header. For example, the duration information may be included in a duration/ID field included in the MAC header.

The operation of the class-based BSS may include a spatial reuse operation. Further, the operation of the class-based BSS may include a channel access operation. The spatial reuse operation may be a channel access operation. When the STA receives the PPDU or the frame, if a preset condition is satisfied, the STA may perform a spatial reuse operation. The preset condition may include a condition corresponding to the inter-BSS with the received PPDU or the received frame. In addition, the preset condition may include a condition that the signal strength of the received PPDU or frame is less than a threshold value. For example, the threshold may be variable. Further, the threshold may be a threshold for OBSS PD-based spatial reuse operation. Further, the threshold may be a value greater than or equal to the CCA threshold. Further, the threshold may be a value based on the power to be transmitted. The spatial reuse operation may include an operation of transmitting a PPDU. Further, the spatial reuse operation may include an operation to reset the PHY. For example, the operation to reset the PHY may be an operation to issue a PHY-ccareset. Further, the spatial reuse operation may include an operation of not setting a NAV based on the received PPDU or the received frame. If the STA performs the spatial reuse operation, the STA may transmit the PPDU during which the received PPDU or frame is transmitted or received.

Referring to fig. 13, BSS a and BSS B may exist, and BSS a and BSS B may be different BSSs. Further, BSS a and BSS B may correspond to each other between BSSs. That is, PPDUs or frames transmitted by STAs associated with BSS a in BSS B may be classified as inter-BSS PPDUs or inter-BSS frames. Further, there may be STAs 1 and 2 belonging to (or associated with) BSS a (or an AP operating BSS a). There may be STAs 3 and 4 belonging to (or associated with) BSS B (or AP running BSS B). Referring to fig. 13, sta 1 may transmit a PPDU. In addition, the PPDU transmitted by the STA 1 may include information about the BSS. For example, the information about the BSS may be information for classifying the BSS. In addition, the PPDU transmitted by the STA 1 may include duration information.

STA 2 may receive the PPDU transmitted by STA 1 and classify the BSS of the PPDU. In addition, since STA 2 and STA 1 belong to BSS a, PPDUs received by STA 2 may be classified as intra-BSS PPDUs. In addition, the PPDU received by the STA 2 may be a UL PPDU or may be a PPDU whose mandatory receiver is not an STA. Therefore, according to the above-described embodiments, STA 2 can perform power saving within the PPDU. Referring to fig. 13, sta 2 may enter a doze state until the end time of the received PPDU. STA 2 may set the NAV based on duration information included in the received PPDU. Since STA 2 classifies the received PPDU as an intra-BSS PPDU, STA 2 may set an intra-BSS NAV.

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

STA 4 may receive the PPDU transmitted from STA 1 and classify the BSS of the PPDU. In addition, since STA 4 and STA 1 belong to BSS B and BSS a, respectively, PPDUs received by STA 4 may be classified as inter-BSS PPDUs. Further, the signal strength of the PPDU received by the STA 4 may be less than the threshold. Accordingly, since PPDUs received by the STA 4 are classified as inter-BSS PPDUs and signal strengths of PPDUs received by the STA 4 are less than a threshold, the STA 4 can perform a spatial reuse operation. Thus, the STA 4 can perform channel access and backoff procedures and can start transmission. For example, STA 4 may start transmitting at a point in time when the PPDU transmitted by STA 1 has not ended.

Fig. 14 illustrates the functions of a station according to an embodiment of the present invention.

According to an embodiment of the present invention, a station following a certain wireless LAN standard may include the functions of the previous wireless LAN standard. This is for downward compatibility. For example, a station supporting a specific wireless LAN standard may support a previous generation wireless LAN standard function, and may also support a new function. For example, the HT station may support basic functions of an OFDM PHY station. Accordingly, the HT station may be classified as an OFDM PHY station. In addition, the HT station supports not only the function of the OFDM PHY station but also additional functions not supporting the OFDM PHY station. The VHT station may support functions not supported by the HT station while supporting basic functions of the HT station. VHT stations may be classified as HT stations. In addition, the HE station may support functions not supported by the VHT station while supporting basic functions of the VHT station. HE stations may be classified as VHT stations. The EHT STA may be an HE STA. In addition, the EHT station may support functions not supported by the HE station while supporting basic functions of the HE station. Further, the EHT station may be classified as an HE station. Further, the wireless LAN standard after the EHT standard may be redefined. In the present invention, a standard following the EHT standard is referred to as a NEXT standard, and a station following the NEXT standard is referred to as a NEXT station. The NEXT station may support functions that the EHT station does not support while supporting the basic functions of the EHT station. NEXT stations may be classified as EHT stations.

Fig. 14 is a diagram illustrating a relationship between stations supporting respective wireless LAN standards. Referring to fig. 11, the eht station may be an HE station, may be a VHT station, may be an HT station, and may be an OFDM PHY station. Further, the NEXT station may be an EHT station, may be an HE station, may be a VHT station, may be an HT station, may be an OFDM PHY station.

Fig. 16 illustrates UL MU operation according to an embodiment of the present invention.

In one embodiment of the present invention, an access point may send a frame that causes a multi-user (MU) transmission. Such frames are called trigger frames. In this case, one or more stations that have received the trigger frame may perform uplink transmission based on the trigger frame. In particular, one or more stations that have received the trigger frame may transmit a response frame for the frame. In this case, an interval (inter-space) between the PPDU including the trigger frame and the PPDU for uplink transmission may be SIFS. Specifically, multiple stations may receive the trigger frame and simultaneously (simultaneity) transmit an immediate (immediate) response. The immediate response indicates that the interval between the previously received PPDU and the PPDU including the response is SIFS.

The trigger frame is a control frame and may be a trigger frame including trigger information. Further, the trigger frame may be a frame including trigger information in the MAC header. In this case, the trigger information may be a trigger response schedule (TRS; triggered response scheduling) included in an HT control field, a control subfield, or an A-control subfield of the MAC header. Further, the trigger information may be information causing transmission of the TB PPDU.

The TB PPDU is a PPDU format including a response frame to a trigger frame. The TB PPDU may include a HE TB PPDU and an EHT TB PPDU. In addition, the TB PPDU may include a NEXT TB PPDU defined in the NEXT wireless LAN standard. The HETB PPDU may include a preamble sequentially including L-STF, L-LTF, L-SIG, RL-SIG, HE-SIG-A, HE-STF, and HE-LTF, and may include data and Packet Extension (PE) after the preamble. In addition, the EHT TB PPDU and the NEXT TB PPDU may include preambles sequentially including L-STF, L-LTF, L-SIG, RL-SIG, U-SIG, (EHT-/NEXT-) STF, and (EHT-/NEXT-) LTF, and may include data and Packet Extensions (PEs) after the preambles.

The trigger frame may include information required to transmit the TB PPDU. If the value of the type subfield (B3B 2) of the MAC frame is 01 _b And the value of the subtype subfield (B7B 6B 5B 4) is 0010 _b The frame may be a MAC frame trigger frame.

When a plurality of stations responding to a trigger frame transmit TB PPDUs of different formats, it may be difficult for an access point to receive the TB PPDUs. In addition, when preambles of PPDUs transmitted by a plurality of stations are different from each other, it may be difficult for an access point to receive a TB PPDU. In particular, when RUs transmitting different formats of TB PPDUs overlap each other, it may be difficult for an access point to receive the TB PPDUs. Thus, a plurality of stations transmitting a response for one trigger frame may use the same format TB PPDU. Further, the preamble information of the TB PPDU transmitted by a plurality of stations transmitting a response for one trigger frame may be the same.

As described with reference to fig. 14, the HE station may transmit the HE TB PPDU. Further, the EHT station may transmit an EHT TB PPDU or an HE TB PPDU. Further, the NEXT station may transmit a NEXT TB PPDU, an EHT TB PPDU, or an HE TB PPDU.

In the embodiment of fig. 15, the AP transmits a trigger frame for scheduling transmission of the HE station (HE STA) and transmission of the EHT station (EHT STA). In this case, in a case where the trigger frame does not indicate the format of the TB PPDU to be transmitted in response to the trigger frame, the HE station (HE STA) and the EHT station (EHT STA) or EHT stations (EHT STA) different from each other may transmit the TB PPDU of different formats. Thus, transmission of the TB PPDU may fail and transmission opportunities may be wasted. For convenience of description, trigger frames defined in the HE, EHT, and NEXT standards are referred to as an HE trigger frame, an EHT trigger frame, and a NEXT trigger frame, respectively. Further, TRSs defined in the HE, EHT, and NEXT standards are referred to as HE TRS, EHT TRS, and NEXT TRS. The format of the trigger frame will be described with reference to fig. 13.

Fig. 16 illustrates a format of a trigger frame and subfields included in the trigger frame according to an embodiment of the present invention.

Specifically, fig. 16 (a) illustrates a format of a trigger frame, fig. 16 (b) illustrates a Common information (Common Info) field of the trigger frame, and fig. 16 (c) illustrates a User information (User Info) field of the trigger frame. The MAC header of the trigger Frame includes a Frame Control (Frame Control) field, a Duration (Duration) field, and an Address (Address) field. In this case, the address field includes an RA field and a TA field. The trigger frame includes a common information field and a User information List (User Info List) field. The common information field includes information for all stations triggered by the trigger frame. Further, the user information list field may include a user information field. In particular embodiments, a particular type of trigger frame may not include a user information list field. Further, the trigger frame may include a Padding (Padding) field and an FCS field. The padding field may be used to increase the frame length to ensure the time required for the STA receiving the trigger frame to prepare for the response, and an optional (optional) field may be present.

The common information field may include a Trigger Type (Trigger Type) subfield. The trigger type subfield identifies a trigger frame variant (varait). The trigger frame may indicate the type of trigger frame by the value of the trigger frame subfield. Further, the information contained in the trigger-related public information (Trigger Dependent Common Info) subfield, the trigger-related user information (Trigger Dependent User Info) subfield, and the length of the trigger-related public information subfield, the trigger-related user information subfield may be determined according to the trigger type subfield. For example, the trigger type subfield may be represented by bits of B0 to B3 bits of the common information field.

Further, the common information field may include a UL length subfield (UL Length subfield). The UL length subfield may include information on the length of the TB PPDU in response to the trigger frame. Alternatively, the UL length subfield may include information on the length of a frame in response to a trigger frame. Further, the UL length subfield may indicate a value to be included in a length subfield of an L-SIG of a TB PPDU in response to a trigger frame. Accordingly, the STA responding with the TB PPDU may set the length subfield of the L-SIG of the TB PPDU based on the value of the UL length subfield included in the received trigger frame. More specifically, the STA responding with the TB PPDU may set the length subfield of the L-SIG of the TB PPDU to a value of the UL length subfield included in the received trigger frame. For example, the UL length subfield may be represented by bits of B4 to B15 of the common information field.

Further, the common information field may include a UL BW subfield. Ext> theext> ULext> BWext> subfieldext> mayext> indicateext> aext> bandwidthext> (ext> BWext>)ext> valueext> includedext> inext> aext> signalingext> fieldext> (ext> e.g.ext>,ext> aext> HEext> -ext> SIGext> -ext> aext> fieldext> orext> aext> uext> -ext> SIGext> fieldext>)ext> ofext> aext> TBext> PPDUext> inext> responseext> toext> aext> triggerext> frameext>.ext> Further, the UL BW subfield may indicate a maximum bandwidth of the TB PPDU in response to the trigger frame.

Ext> furtherext>,ext> theext> commonext> informationext> fieldext> mayext> includeext> aext> signalingext> fieldext> ofext> aext> TBext> PPDUext> inext> responseext> toext> aext> triggerext> frameext>,ext> forext> exampleext>,ext> anext> HEext> -ext> SIGext> -ext> aext> fieldext> orext> informationext> toext> beext> includedext> inext> aext> uext> -ext> SIGext> fieldext>,ext> etcext>.ext>

The user information field may include an AID12 subfield. The AID12 subfield may serve to indicate an intended recipient of the user information field including the AID12 subfield or to indicate a function of the user information field. Thus, the AID12 subfield may serve to indicate an intended recipient of a trigger frame including the AID12 subfield or to indicate a function of the trigger frame. For example, when the value of the AID12 subfield is a predetermined value, it may be indicated that the user information field indicates a random access resource unit (RA-RU; random access resource unit). More specifically, if the value of the AID12 subfield is 0, the user information field may indicate an RA-RU for the associated (associated) station. Further, if the value of the AID12 subfield is 2045, the user information field may indicate RA-RU for unassociated (unassigned) stations. Further, for a station corresponding to a STA ID (e.g., AID (association ID)) indicated by a value of the AID12 subfield, a user information field including the AID12 subfield or a trigger frame including the AID12 subfield may indicate a trigger response. For example, the AID12 subfield may represent AID or 12 LSBs of AID. A station corresponding to the value of the AID12 subfield may respond to the trigger frame with a TB PPDU. Further, the value of the AID12 subfield may be in the range of 1 to 2007 (including 1 and 2007). Further, when the AID12 subfield has a predetermined value (e.g., 2046), the corresponding RU may indicate that it is not allocated to any station. Further, when the AID12 subfield has a predetermined value (e.g., 4095), the start of the padding of the trigger frame may be indicated.

Further, the information of the user information field including the AID12 subfield may be information corresponding to the station indicated by the AID12 subfield. For example, an RU Allocation (RU Allocation) subfield may indicate the size and location of an RU. In this case, the value of the RU allocation subfield of the user information field including the AID12 subfield may be information corresponding to the station indicated by the AID12 subfield. Further, the user information field may indicate an encoding method (UL FEC encoding type), a modulation method (UL HE-MCS, UL DCM) and a transmission power (UL target RSSI) for a response to a trigger frame including the user information field.

As described above, depending on which PPDU format the TB PPDUs simultaneously transmitted in response to the trigger frame are transmitted in, problems may occur. A transmission method of the trigger frame related thereto will be described with reference to fig. 14.

Fig. 17 illustrates information indicated by a value of an AID12 subfield of a trigger frame according to an embodiment of the present invention.

According to an embodiment of the present invention, the EHT station may selectively transmit the HE TB PPDU and the EHT TB PPDU. In addition, the NEXT station may selectively transmit the HE TB PPDU, the EHT TB PPDU, and the NEXT TB PPDU. Thus, stations of a plurality of wireless LAN standards can be scheduled using one frame or one PPDU. Therefore, the use efficiency of the transmission medium can be improved. For example, an HE station and an EHT station that do not support the EHT standard may be caused to respond with an HE TB PPDU of one frame.

Further, information for selecting a TB PPDU format may be included in a trigger frame, a TRS, or a PPDU including a trigger frame, or a PPDU including a TRS.

According to an embodiment of the present invention, information on the response TB PPDU format may exist at the MAC layer. According to an embodiment of the present invention, the trigger frame may be divided into an HE trigger frame, an EHT trigger frame, and a NEXT trigger frame. In addition, the responses triggered by the HE trigger frame, the EHT trigger frame, and the NEXT trigger frame may be responded with the HE TB PPDU, the EHT TB PPDU, and the NEXT TB PPDU, respectively.

Further, distinguishing the HE trigger frame, the EHT trigger frame, and the NEXT trigger frame may mean distinguishing the TB PPDU format to be responsive to the trigger frame into the HE TB PPDU, the EHT TB PPDU, and the NEXT TB PPDU, respectively. That is, depending on the format of the trigger frame, the format of the TB PPDU for the trigger frame may also be changed, and the next generation trigger frame may simultaneously indicate the transmission of the previous generation TB PPDU. That is, the EHT trigger frame may indicate the transmission of the HE TB PPDU and the EHT TB PPDU at the same time. However, the HE trigger frame cannot indicate the transmission of the EHT TB PPDU.

In a specific embodiment, it may be determined which of the HE trigger frame, the EHT trigger frame, and the NEXT trigger frame the trigger frame corresponds to according to a frame control field of a MAC header included in the trigger frame. For example, it may be determined which of the HE trigger frame, the EHT trigger frame, and the NEXT trigger frame corresponds to the trigger frame according to at least one of a Type (Type) subfield, a Subtype (Subtype) subfield, or a control frame extension (Control Frame Extension) subfield of a frame control field of a MAC header included in the trigger frame. For example, when a type subfield, a subtype subfield, or a control frame extension subfield of a frame control field of a MAC header included in a trigger frame is a first value, the trigger frame may be classified as an HE trigger frame. Further, when the type subfield, the subtype subfield, or the control frame extension subfield of the frame control field of the MAC header included in the trigger frame is a second value, the trigger frame may be classified as an EHT trigger frame. Further, when the type subfield, the subtype subfield, or the control frame extension subfield of the frame control field of the MAC header included in the trigger frame is a third value, the trigger frame may be classified as a NEXT trigger frame. When the value of the type subfield of the frame control field of the MAC header is 01 _b And the value of the subtype subfield is 0010 _b When the trigger frame may be classified as HE trigger frame. Each of the type subfield, the subtype subfield, and the control frame extension subfield is limited to 2 bits, 4 bits, and 4 ratiosBits. Thus, such an embodiment has the disadvantage of using the value of the limited bit field to limit the types available in the future.

In another particular embodiment, it may be determined which of the HE trigger frame, the EHT trigger frame, and the NEXT trigger frame the trigger frame corresponds to according to a common information field included in the trigger frame. For example, when the value of the trigger type subfield of the common information field of the trigger frame is a first value, the trigger frame may be classified as an HE trigger frame. When the value of the trigger type subfield of the common information field of the trigger frame is a second value, the trigger frame may be classified as an EHT trigger frame. When the value of the trigger type subfield of the common information field of the trigger frame is a third value, the trigger frame may be classified as a NEXT trigger frame. Specifically, when the value of the trigger type subfield of the common information field of the trigger frame is 0 to 7, the trigger frame may be classified as an HE trigger frame. Further, when the value of the trigger type subfield of the common information field of the trigger frame is not 0 to 7, the trigger frame may be classified as an EHT trigger frame or a NEXT trigger frame. Since the number of bits of the trigger type subfield is limited, this embodiment has the disadvantage of using the value of the limited bit field to limit the trigger types that can be used in the future.

In another specific embodiment, it may be determined which trigger frame of the HE trigger frame, the EHT trigger frame, and the NEXT trigger frame corresponds to the trigger frame according to the UL length field included in the trigger frame. For example, when a remainder obtained by dividing a value of an UL length field of the trigger frame by 3 is a first value, the trigger frame may be classified as an HE trigger frame. When a remainder value obtained by dividing a value of an UL length field of the trigger frame by 3 is a second value, the trigger frame may be classified as an EHT trigger frame. When the remainder obtained by dividing the value of the UL length field of the trigger frame by 3 is a third value, the trigger frame may be classified as a NEXT trigger frame. When the remainder obtained by dividing the value of the UL length field of the trigger frame by 3 is not 0, the trigger frame may be classified as an HE trigger frame. When the remainder obtained by dividing the value of the UL length field of the trigger frame by 3 is 1, the trigger frame may be classified as an HE trigger frame. When the remainder obtained by dividing the value of the UL length field of the trigger frame by 3 is 0, the trigger frame may be classified as an EHT trigger frame or a NEXT trigger frame. Further, it may be determined which of the HE trigger frame, the EHT trigger frame, and the NEXT trigger frame the trigger frame corresponds to according to a value of an UL length field of the trigger frame and at least one of a format identifier (Format Identifier), a PHY identifier, and TB PPDU format signaling of the trigger frame.

In another specific embodiment, it may be determined which trigger frame of the HE trigger frame, the EHT trigger frame, and the NEXT trigger frame corresponds to the trigger frame according to the user information field included in the trigger frame. In particular, it may be determined which of the HE trigger frame, the EHT trigger frame, and the NEXT trigger frame the trigger frame corresponds to according to the value of the AID12 subfield of the user information field of the trigger frame. For example, it may be determined which of the HE trigger frame, the EHT trigger frame, and the NEXT trigger frame the trigger frame corresponds to according to whether the value of the AID12 subfield of the user information field of the trigger frame is a pre-specified value. In this case, the user information field including the AID12 subfield indicating the type of the trigger frame may be the first user information field in the user information field list. The user information field including the AID12 subfield indicating the type of the trigger frame may be located before the user information field including the AID12 subfield indicating the AID of the station. Thus, the station receiving the trigger frame can determine the type of the trigger frame at an early stage. In another particular embodiment, the user information field including the AID12 subfield indicating the type of the trigger frame may be located after the user information field for the HE station in the user information field list. Thus, problems due to the fact that the legacy station (i.e., HE station) cannot determine the meaning of the value of the AID12 subfield can be prevented. Further, the user information field including the AID12 subfield indicating the type of the trigger frame may not include subfields other than the AID12 subfield. This is because the corresponding user information field is used to indicate the trigger frame type, and thus information other than the trigger frame type may not be required. In this embodiment, the length of the user information field varies according to the value of the AID12 subfield. Fig. 17 illustrates the meaning represented by the value of the AID12 subfield when this embodiment is applied. When the value of the AID12 subfield is a first value, the AID12 subfield may indicate that a trigger frame including the AID12 subfield triggers transmission of the EHT TB PPDU. The first value may be 2047. When the value of the AID12 subfield is the second value, the AID12 subfield may indicate that a trigger frame including the AID12 subfield triggers transmission of a NEXT TB PPDU. The second value may be 2048.

In another particular embodiment, the station may determine the format of the TB PPDU transmitted as a response to the trigger frame according to the location of the user information field of the trigger station. In particular, the station may determine the format of the TB PPDU transmitted as a response to the trigger frame based on whether the user information field of the trigger station is located after the user information field including the AID12 subfield having a predetermined value. In this case, the station may determine the format of the TB PPDU transmitted as a response to the trigger frame based on whether the user information field of the trigger station is located after the user information field including the AID12 subfield having the first value and whether the user information field is located after the user information field including the AID12 subfield having the second value. In the embodiment of fig. 17, when the user information field of the trigger station is located after the user information field including the AID12 subfield having 2047, the station may transmit the EHT TB PPDU in response to the trigger frame. Further, when the user information field of the trigger station is located after the user information field including the AID12 subfield having 2048, the station may transmit the NEXT TB PPDU in response to the trigger frame. Further, when the user information field of the trigger station is located after the user information field including the AID12 subfield having 2047 and the user information field including the AID12 subfield having 2048, the station may transmit the NEXT TB PPDU in response to the trigger frame. Further, when the user information field of the trigger station is located before the user information field including the AID12 subfield having 2047 and the user information field including the AID12 subfield having 2048, the station may transmit the HE TB PPDU in response to the trigger frame.

Which of the HE trigger frame, the EHT trigger frame, and the NEXT trigger frame corresponds to may be determined by subfields other than the AID12 subfield in the user information field.

It may be determined which trigger frame of the HE trigger frame, the EHT trigger frame, and the NEXT trigger frame corresponds to the trigger frame according to the padding field of the trigger frame. For example, it may be determined which trigger frame of the HE, EHT, and NEXT trigger frames the trigger frame corresponds to according to whether the padding field of the trigger frame contains a pre-specified value.

Furthermore, the foregoing embodiments may be applied in combination. For example, the determination may be made by combining elements affecting whether the trigger frame is the HE trigger frame, the EHT trigger frame, or the NEXT trigger frame described above.

Further, the foregoing embodiments may be used to determine the format of a TB PPDU to be transmitted as a response to a TRS field.

Fig. 18 illustrates UL MU operation according to an embodiment of the present invention.

As described above, the trigger frame may include a TRS in the MAC frame header. As described above, the TRS may be included in the HT control field. In particular, when the HT control field includes an a-control field, the HT control field may include a TRS. Further, the TRS may be included in a TRS control field. The Control List field may be located continuously in the a-Control field. In this case, the control list field may include a TRS.

A station corresponding to an intended receiver of a MAC frame including a TRS may transmit a PPDU based on the TRS field. In this case, the TRS may include information (UL Data Symbols) on the length of a PPDU or frame to be transmitted by the station in response to the MAC frame including the TRS. Information on power (AP Tx power, UL target RSSI) transmitted for a response to a MAC frame including a TRS, a location and a size (RU allocation) of an RU for transmitting a response to a MAC frame including a TRS, and information on a modulation method (UL HE-MCS) transmitted for a response to a MAC frame including a TRS.

The TRS may be defined according to a wireless LAN standard. In this case, the station having received the MAC frame including the TRS may determine the format of the TB PPDU to be transmitted as a response to the TRS according to the format of the TRS (i.e., according to the TRS defined in which wireless LAN standard). Specifically, when the station receives the HE TRS, the station may transmit the HE TB PPDU in response to the TRS. Further, when the station receives the EHT TRS, the station may transmit the EHT TB PPDU in response to the TRS. Further, when the station receives the NEXT TRS, the station may transmit a NEXT TB PPDU in response to the TRS. In this case, the station may determine which wireless LAN standard the TRS defined in based on the control ID subfield of the a-control subfield. The TRSs may be classified into HE TRSs and TRSs other than HE TRSs.

The format of the TRS may be determined according to whether an HT control field including the TRS is a HE variant (variant), an EHT variant, or a NEXT variant. The TRS may be an EHT TRS if the HT control field including the TRS is an EHT variant. Further, if the HT control field including the TRS is a NEXT variant, the TRS may be a NEXT TRS. Further, the format of the TRS may be determined according to a value of a predetermined bit among bits including the HT control field of the TRS, according to whether the HT control field is the HE variant, the EHT variant, or the NEXT variant. For example, when the values of the first bit B0 and the second bit B1 of the HT control field are 11 _b In this case, the HT control field may be a HE variant. Further, whether the HT control field is the HE variant, the EHT variant, or the NEXT variant may be determined based on the first and second bits B0 and B1 of the HT control field and additional bits (e.g., bit 32B 31).

In an embodiment of fig. 18, when a TRS is included in the HE PPDU, a station receiving the HE PPDU may transmit the HE TB PPDU in response to the TRS. When the TRS is included in the EHT PPDU, a station that receives the EHT PPDU transmits the EHT TB PPDU in response to the TRS. When a TRS is included in the NEXT PPDU, a station receiving the NEXT PPDU transmits the NEXT TB PPDU in response to the TRS.

Further, the information represented by the subfields included in the TRS may be changed according to a PPDU format including the TRS. If the TRS is included in the HE PPDU, an MCS-related subfield (e.g., UL HE-MCS subfield) included in the TRS may indicate a value corresponding to the HE MCS table. Further, if a TRS is included in the EHT PPDU, an MCS-related subfield (e.g., UL HE-MCS subfield) included in the TRS may indicate a value corresponding to the EHT MCS table. Further, if a TRS is included in the NEXT PPDU, an MCS-related subfield (e.g., UL HE-MCS subfield) included in the TRS may indicate a value corresponding to the NEXT MCS table. Further, the information represented by the RU-allocation subfield may be changed according to a PPDU format including the TRS.

Fig. 19 illustrates an example of a method for sharing a TXOP in accordance with an embodiment of the present invention.

Referring to fig. 19, a part or all of a TXOP set by an AP may be shared to a non-AP STA, and the non-AP STA may transmit a PPDU (PLCP protocol data unit) to another non-AP STA (third STA) and/or an AP using the shared TXOP. Hereinafter, in the present invention, an operation of sharing a TXOP to another STA may be referred to as TXOP sharing. Further, the STA may be an AP or an AP-STA that transmits a trigger frame, or may be a non-AP STA that receives a trigger frame. The STAs may share or be shared with the TXOP.

Specifically, the STA may set (or obtain) the TXOP by receiving a response to a frame for setting the TXOP after transmitting the frame. After setting the TXOP, the STA may perform TXOP sharing by sharing the set TXOP. The response to the frame for setting the TXOP may include information about the length of the TXOP, and the length of the TXOP may be greater than 0. In this case, the response to the frame for setting the TXOP may be an immediate response (immediate response), and the response may be transmitted after a certain time (e.g., SIFS) elapses from the end of the frame for setting the TXOP (e.g., PPDU).

The length of the TXOP may be indicated based on duration information included in a frame transmitted by the STA. For example, the duration information may be included in a duration/ID field of a MAC header of the PPDU, and the length of the TXOP may be based on the duration information. The length of the TXOP may be included in a preamble included in a PPDU of a frame transmitted by the STA. Ext> thatext> isext>,ext> theext> durationext> informationext> mayext> beext> includedext> inext> aext> TXOPext> fieldext> includedext> inext> aext> signalingext> fieldext> (ext> signalingext> fieldext>)ext> ofext> theext> PPDUext>,ext> andext> theext> signalingext> fieldext> mayext> beext> aext> HEext> -ext> SIGext> -ext> aext> fieldext> orext> aext> uext> -ext> SIGext> fieldext>.ext>

The TXOPs may be shared within the set TXOPs and one or more TXOPs may be shared during the set TXOPs. For example, within a TXOP set by a STA, one or more TXOPs may be shared with another STA.

During the shared TXOP, the STA receiving the TXOP share may transmit a PPDU to the STA sharing the TXOP or another STA, and in this case, the transmitted PPDU may not be a TB PPDU (e.g., a non-TB PPDU). That is, STAs receiving TXOP sharing may transmit PPDUs during the shared TXOP even if a trigger frame is not received from the AP. In other words, even if RU is not separately allocated, an STA receiving TXOP sharing may transmit PPDUs during the shared TXOP with RU allocated by a trigger frame transmitted at the time of receiving the TXOP sharing (even if additional trigger frames are not received) until the TXOP is terminated. Thus, examples of PPDUs transmitted by STAs during the shared TXOP may include non-HT PPDUs, HE PPDUs, VHT PPDUs, HE SU PPDUs, or EHT MU PPDUs.

For TXOP sharing, an STA receiving TXOP sharing during the shared TXOP may transmit a frame to the STA or a third STA (another STA) sharing the TXOP. For example, when the AP sets a TXOP and shares a part or all of the set TXOP to the STA, the STA receiving the TXOP may transmit a frame to the AP or the third STA sharing the TXOP. In this case, since the frame transmitted from the STA to the third STA may be a frame transmitted between non-AP STAs, the frame may be a peer-to-peer (P2P) frame.

Sharing of TXOPs may be set by a particular frame. That is, a part or all of the set TXOPs may be indicated to be shared by a specific frame, and the STA may receive a corresponding frame to use the shared TXOPs. In this case, a specific frame may be transmitted by STAs sharing the TXOP. For example, TXOP sharing may be performed by a trigger frame transmitted by an AP. In this case, the trigger frame for TXOP sharing may be a specific type of trigger frame (e.g., MU-RTS frame or MU-RTS trigger frame, etc.), and may be identified by the value of the trigger type subfield of the trigger frame described in fig. 16. That is, when the value of the trigger type subfield is set to a predetermined value (e.g., "3"), the STA receiving the trigger frame may recognize that the TXOP is shared and may transmit the PPDU through the shared TXOP.

The MU-RTS frame, which is a frame for TXOP sharing, may be a frame indicating that a CTS frame is transmitted from one or more STAs. For example, a CTS frame may be sent as an immediate response to a MU-RTS frame, and the CTS frame may be a non-HT PPDU. Hereinafter, in the present invention, the MU-RTS frame for sharing the TXOP may be referred to as a modified MU-RTS frame or a MU-RTS TXS trigger frame. However, the present invention is not limited thereto, and frames for TXOP sharing may have various names.

The sharing of a part or all of the TXOP may be set to only one STA or may be set to one or more STAs. That is, in the case of sharing a TXOP by a frame, one or more STAs for TXOP sharing may be indicated by the frame. In this case, as described above, sharing of the TXOP may be set within the TXOP set by the sharing STA. That is, the shared TXOP cannot exceed the TXOP set by the sharing STA.

The duration of the shared TXOP may be indicated by a particular frame (e.g., a modified MU-RTS frame) used to share the TXOP. For example, the modified MU-RTS frame may include a UL length subfield, and the UL length subfield may include the duration of the shared TXOP. In this case, the UL length subfield may be the UL length subfield described with reference to fig. 16. When the trigger frame indicates transmission of the TB PPDU, the UL length subfield may include information about the length of the indicated TB PPDU (or interval information for transmission of the TB PPDU).

Whether the transmitted MU-RTS frame is a MU-RTS frame for sharing the TXOP (modified MU-RTS frame) or a MU-RTS frame not for sharing the TXOP may be indicated by a specific field included in the frame. For example, if the value of a specific field included in the frame is a predetermined value, the corresponding MU-RTS frame may be a modified MU-RTS frame for TXOP sharing. In this case, the specific frame may be a GI And HE-LTF type (GI And HE-LTF) subfield. For example, when the type field included in the trigger frame indicates the MU-RTS frame, whether the MU-RTS frame is a trigger frame for sharing the TXOP may be identified according to the values of the GI and HE-LTF type subfields. That is, when the GI and HE-LTF type subfields are set to predetermined values, the corresponding trigger frame may be a trigger frame for the shared TXOP (e.g., a modified MU-RTS frame or a MU-RTS TXS trigger frame).

Alternatively, it may be determined whether the received frame is a MU-RTS frame (modified MU-RTS frame or MU-RTS TXS trigger frame) for the shared TXOP based on whether a specific field and/or the number of specific fields are included in the MU-RTS frame. In this case, the specific field may be a User information field (User Info field) or a User information list field (User Info List field) described with reference to fig. 16. In particular, whether the received MU-RTS frame is a frame for TXOP sharing may be determined based on the number of user information fields included in the MU-RTS frame. For example, if the MU-RTS frame does not include a user information field (if the number of user information fields is "0"), the corresponding MU-RTS frame may be a frame for TXOP sharing. In this case, if the MU-RTS frame is not a frame for TXOP sharing, the corresponding MU-RTS frame may be a MU-RTS frame indicating to one or more STAs to transmit an existing CTS frame, or the existing MU-RTS frame may be a MU-RTS frame defined in the 802.11ax standard.

Immediately after transmitting the CTS frame as a response to the existing MU-RTS frame, the STA (e.g., AP) that transmitted the existing MU-RTS frame may transmit a frame or PPDU. Further, immediately after transmitting the CTS frame as a response to the modified MU-RTS frame, the STA that transmitted the CTS frame may transmit a frame or PPDU. Alternatively, in response to the modified MU-RTS frame, the STA receiving the TXOP share may send a frame or PPDU that is not a CTS frame. In this case, the frame and the PPDU may be a frame transmitted by the STA shared by the receiving TXOP during the above-described shared TXOP and a PPDU including a frame transmitted by the STA shared by the receiving TXOP during the shared TXOP, respectively. That is, the frame or PPDU may be a frame or PPDU toward the AP or a P2P frame.

In the present invention, the referred MU-RTS frame may be an existing MU-RTS frame. That is, in the present invention, the referred MU-RTS frame may not be a modified MU-RTS frame.

According to an embodiment of the invention, the CTS frame may be transmitted in response to a modified MU-RTS frame. The CTS frame may be transmitted by STAs that receive the TXOP share. In this case, the STA receiving the TXOP sharing may transmit a frame immediately after transmitting the CTS frame. The STA receiving the TXOP sharing may transmit a frame immediately after transmitting a PPDU including a CTS frame. The frame transmitted immediately after the CTS frame is transmitted may be included in a PPDU transmitted by an STA shared by the receiving TXOP during the shared TXOP. Alternatively, a frame transmitted immediately after the CTS frame is transmitted may be included in the non-TB PPDU and transmitted as described above. Further, in the present invention, immediately transmitting may mean transmitting after SIFS or PIFS time elapses from the end of the PPDU including the CTS frame. The CTS frame may be used to inform STAs receiving TXOP sharing that TXOP sharing has been received.

According to a further embodiment, a CTS frame may not be transmitted in response to a modified MU-RTS frame. STAs receiving TXOP sharing immediately after the modified MU-RTS frame may send frames. Alternatively, STAs receiving TXOP sharing immediately after the PPDU including the modified MU-RTS frame may transmit the PPDU. In this case, the transmitted frame may be included in a PPDU transmitted by an STA that receives the TXOP sharing during the TXOP shared as described above. Alternatively, the frame transmitted in this case may be included in the non-TB PPDU and transmitted as described above. Further, in the present invention, immediately transmitting may mean transmitting after SIFS or PIFS time elapses from the end of the PPDU including the modified MU-RTS frame.

According to an embodiment, the modified MU-RTS frame may include signaling as to whether STAs receiving the TXOP share should send a CTS frame. According to an embodiment, when a STA receiving TXOP sharing transmits a frame to be transmitted to an AP, the shared TXOP may be used without a CTS frame. Further, when a STA receiving TXOP sharing transmits a P2P frame, a CTS frame may be transmitted and the shared TXOP may be used. In addition, when the STA receiving the TXOP sharing transmits a P2P frame, the RA field of the CTS frame transmitted immediately after the modified MU-RTS frame may also be set to the MAC address of the STA transmitting the modified MU-RTS frame. This is because, when an STA receiving the TXOP sharing does not transmit a frame including an address of an STA that transmitted the modified MU-RTS frame after receiving the modified MU-RTS frame, an STA performing TXOP sharing may have difficulty in knowing whether the STA receiving the TXOP sharing successfully received the modified MU-RTS frame.

Referring to fig. 19, STA 1 and STA 2 may exist, and STA 1 and STA 2 may be associated with each other (association). Further, STA 1 may be an AP. STA 2 may be a non-AP STA. STA 1 may send a MU-RTS frame. The MU-RTS frame may be an existing MU-RTS frame. The MU-RTS frame may include duration information regarding the TXOP duration. The MU-RTS frame may request (solicit) CTS frames from one or more STAs. In this case, the one or more STAs may include STA 2.STA 2 may send a CTS frame in response to the MU-RTS frame. In this case, STA 1 may be the TXOP holder. The TXOP holder may be an STA that obtains the TXOP. During a TXOP, the TXOP holder may transmit the desired frame. Further, in this case, STA 2 may become a TXOP responder. The TXOP responders may be STAs that transmit responses to frames transmitted by the TXOP holder. The TXOP responders may send a response to the frame sent by the TXOP holder during the TXOP. Alternatively, during a TXOP, the TXOP responder may send frames allowed by the TXOP holder. In the embodiment of fig. 19, an example of obtaining a TXOP based on exchange of MU-RTS frames, CTS frames is described, but the present invention is not limited thereto, but is also applicable to an example of obtaining a TXOP based on exchange of other frames.

In fig. 19, STA 1 may perform TXOP sharing after acquiring the TXOP. For example, STA 1 may send a modified MU-RTS frame, which is a frame informing of TXOP sharing. For example, a modified MU-RTS frame may be sent to STA 2. The Transmitter Address (TA) of the modified MU-RTS frame may be set to the MAC address of STA 1 or a value based on the MAC address of STA 1. The Receiver Address (RA) of the modified MU-RTS frame may be set to the MAC address of STA 2 or a value based on the MAC address of STA 2. Further, the AID12 subfield value of the user information field included in the modified MU-RTS frame may indicate STA 2. That is, the AID12 subfield value of the user information field included in the modified MU-RTS frame may indicate 12 LSBs of the AID of STA 2. The modified MU-RTS frame may include information about the duration of the shared TXOP.

According to an embodiment, STA 2 may send a CTS frame in response to a modified MU-RTS frame. Further, STA 2 may transmit a frame after transmitting the CTS frame. The frame transmitted after STA 2 transmits the CTS frame may not be a CTS frame. According to another embodiment, STA 2 may not send a CTS frame as a response to a modified MU-RTS frame. In this case, STA 2 may transmit a frame other than the CTS frame after the modified MU-RTS frame is transmitted. Further, the frame that is not a CTS frame, which is transmitted after STA 2 receives the modified MU-RTS frame, may be a frame to be transmitted to STA 1 according to an embodiment. According to another embodiment, the frame that is not a CTS frame, which is transmitted after STA 2 receives the modified MU-RTS frame, may be a frame to be transmitted to STA 3.

For example, the AP may set the TXOP of the AP by sending a trigger frame to a non-AP STA (or STA). In this case, when the AP wants to share a part or all of the TXOP set by the AP with the non-AP STA to which the trigger frame is transmitted, the AP may set specific fields (e.g., GI and HE-LTF type subfields) of the trigger frame to a predetermined value to transmit. In this case, the specific field may be referred to as a TXOP shared mode subfield of GI and HE-LTF type/trigger (triggered TXOP sharing mode subfield). In particular, when the AP does not share the TXOP set by the AP, the GI and HE-LTF type/triggered TXOP sharing mode subfield may be set to "0" and may be interpreted as a GI and HE-LTF type subfield. However, when the AP does not share the TXOP set by the AP, the GI and HE-LTF type/triggered TXOP sharing mode subfield may be interpreted as being set to a value of "1" or "2" and may be interpreted as a TXOP sharing mode subfield. If the value of the GI and HE-LTF type/triggered TXOP shared mode subfield is "1" or "2", the corresponding trigger frame may be referred to as a modified MU-RTS frame or MU-RTS TXS trigger frame. When the AP shares a part or all of the TXOPs set by the AP, the GI and HE-LTF type/triggered TXOP sharing mode subfield of the trigger frame for TXOP sharing indicates a sharing mode of the TXOP. For example, the GI and HE-LTF type/triggered TXOP sharing mode subfield indicates whether the sharing of the TXOP is shared only in transmission and reception with an AP that sets the TXOP or in transmission and reception with a third STA (another STA) and transmission and reception of the AP. That is, when the value of the TXOP sharing mode subfield of the GI and HE-LTF types/triggers is "1", the STA may transmit only the PPDU to the AP during the shared TXOP. However, when the value of the TXOP sharing mode subfield of the GI and HE-LTF type/trigger is "2", the STA may transmit the PPDU to the AP and another STA during the shared TXOP. For example, when the value of the TXOP sharing mode subfield of the GI and HE-LTF types/triggers is "2", the STA may also perform P2P communication during the shared TXOP.

Table 1 below shows an example of TXOP sharing or not according to the values of the GI and HE-LTF types/triggered TXOP sharing mode subfields and modes thereof.

TABLE 1

Fig. 20 illustrates a diagram of a method related to sharing of TXOPs and NAV setting, in accordance with an embodiment of the present invention.

The embodiment of fig. 20 may be an embodiment describing a problem that the operation described in fig. 19 is difficult to perform and a method of solving the problem. What has been described in fig. 19 may be omitted.

According to an embodiment of the present invention, the STA may set a Network Allocation Vector (NAV) based on duration information included in the received frame or the received PPDU. Whether the virtual Carrier Sense (CS) result is idle or busy may be determined based on whether the NAV is set. When the NAV value is 0, the virtual CS result may be an idle state. When the NAV value is greater than 0, the virtual CS result may be an occupied state. The physical CS may be Clear Channel Assessment (CCA). If at least one of the virtual CS and the physical CS is an occupied state, the CS result may be an occupied state. If both the virtual CS and the physical CS are idle states, the CS result may be an idle state. Further, the STA may include a plurality of NAVs. For example, the STA may include an intra-BSS (intra-BSS) NAV and a basic NAV. The intra-BSS NAV may be a NAV set by an intra-BSS frame or an intra-BSS PPDU. The regular NAV may be a NAV set by an inter-BSS frame or an inter-BSS PPDU or a frame or PPDU that cannot determine whether it is intra-BSS or inter-BSS. Further, the virtual CS may be in an occupied state when at least one of the NAV and the basic NAV within the BSS has a value greater than 0. Alternatively, the NAV may have a value greater than 0 when at least one of the NAV and the basic NAV within the BSS has a value greater than 0. The virtual CS may be in an idle state when both the intra-BSS NAV and the basic NAV are 0. Alternatively, the NAV may be 0 when both the NAV and the basic NAV are 0 within the BSS.

For a certain STA, an intra-BSS frame or intra-BSS PPDU may be a frame or PPDU determined to be transmitted from the same BSS as the STA. For a certain STA, an inter-BSS frame or an inter-BSS PPDU may be a frame or PPDU determined to be transmitted from a different BSS from the STA. Further, whether the PPDU is transmitted from the same BSS or from a different BSS may be determined based on a BSS color field included in a preamble of the PPDU, an address field included in a MAC header, and the like. For example, when the BSS color field or address field corresponds to the same BSS, it may be determined as an intra-BSS frame or intra-BSS PPDU. Further, when the BSS color field or the address field does not include a value corresponding to the same BSS, it may be determined as an inter-BSS frame or an inter-BSS PPDU. The address field may include an RA field, a TA field, a BSSID field, etc.

According to an embodiment, when a resource allocation field (RA field) of a frame received by a STA is not its own MAC address, the STA may set a NAV based on the received frame. Alternatively, the STA may set the NAV based on the received trigger frame. More specifically, the STA may set the NAV based on a received trigger frame as an intra-BSS frame. In this case, the NAV may be an intra-BSS NAV. At this time, the NAV may be set regardless of whether the trigger frame triggers the STA. Alternatively, the STA may set the NAV when the received frame or the received PPDU does not indicate an immediate response from the STA.

According to an embodiment of the present invention, when the CS is in an occupied state, the STA may not be able to transmit a frame or PPDU.

According to an embodiment of the present invention, an STA whose NAV is set to a value greater than 0 may not transmit a frame or PPDU. More specifically, an STA whose NAV is set to a value greater than 0 may not transmit a frame or PPDU.

According to an embodiment, when a frame received by a STA is addressed to the STA and an immediate response is requested, the STA may transmit independent of (or irrespective of) the NAV. More specifically, the received frame may not be an RTS frame, but rather a trigger frame. That is, even if the NAV is set to a value greater than 0, when a frame received by an STA is addressed to the STA and an immediate response is requested, the STA can transmit regardless of the NAV. Further, the case where the frame is addressed to the STA may include a case where the RA field of the frame is set to the address of the STA. Alternatively, the case where the frame is addressed to the STA may include the case where the frame includes an identifier corresponding to the STA described above. The identifier may include a MAC address, an Association ID (AID), a MAC address-based ID, an AID-based ID, and the like.

According to another embodiment, when a received frame is sent from the TXOP holder, the STA may send a response to it independent of the NAV. In this case, the NAV may be a NAV set by a frame or PPDU transmitted by the TXOP holder. Alternatively, the NAV may be an intra-BSS NAV. Further, the received frame may be an RTS frame. The frame may be determined to be transmitted from the TXOP holder based on a TA field included in the frame. The STA may store the TXOP holder address. If an STA receives an RTS frame sent by a TXOP holder and the RTS frame is addressed to the STA, the STA may respond to the RTS frame regardless of the NAV. In this case, the CTS frame may be transmitted in response to an RTS frame.

According to another embodiment, when a trigger frame is received, the STA may send a response to it independent of the NAV. In this case, the NAV may be limited to an intra-BSS NAV. Thus, when the NAV is set by the STA of the same BSS or the AP of the same BSS, the STA may transmit a response thereto regardless of the NAV when the trigger frame indicates the response. Upon receiving the trigger frame, the STA may consider the NAV within the BSS, but not the basic NAV, to determine whether to transmit a response thereto. Further, when the STA receives the trigger frame, the STA may determine whether to transmit a response to the trigger frame based on the CS result. For example, the trigger frame may include signaling indicating whether to determine whether to send a response based on CS results when the trigger frame is received. For example, the signaling may be the CS required subfield shown in fig. 16. If the CS needs subfield indication to determine whether to respond based on the CS result, the STA may respond to the trigger frame when the virtual CS and the physical CS indicate the idle state, and the STA may not respond to the trigger frame when the virtual CS or the physical CS indicate the occupied state. In this case, as the virtual CS, a basic NAV may be considered without considering an intra-BSS NAV. Further, if the CS required subfield indicates not to respond based on the CS result, the STA may respond to the trigger frame without checking the CS result.

In the embodiment of fig. 19, the STA receiving the modified MU-RTS frame may not be able to transmit frames other than the CTS frame during the shared TXOP because the NAV is set. This will be described in more detail in fig. 20.

With respect to fig. 20, what has been described in fig. 19 may be omitted. Referring to fig. 20, STA 1 and STA 2 may exist, and STA 1 and STA 2 may be associated with each other. Further, STA 1 may be an AP. STA 2 may be a non-AP STA. STA 1 may send a MU-RTS frame. Further, STA 2 may transmit a CTS frame in response to the MU-RTS frame. In this case, the STA 2 transmits the CTS frame may be because the physical CS result of the STA 2 is an idle state and the basic NAV is not set. Alternatively, STA 2 transmits a CTS frame may be because STA 2 receives a frame addressed to itself and requesting an immediate response. In this case, even in the case where another frame exchange occurs in addition to the exchange of MU-RTS frame, CTS frame, STA 2 can transmit a response frame based on the frame received from STA 1 because the frame is addressed to STA 2 and requests an immediate response. Further, STA 2 may set the NAV based on the MU-RTS frame or another frame other than the MU-RTS frame transmitted by STA 1. The NAV may be an intra-BSS NAV.

Further, STA 1 may perform TXOP sharing for STA 2. That is, STA 1 may transmit a modified MU-RTS frame to STA 2. In this case, as described above, STA 2 may use a shared TXOP: 1) Sending a CTS frame, and then sending other frames; 2) Other frames are sent without sending CTS frames. However, in this case, since the STA 2 is set with the NAV, it may be difficult to transmit the frame. For example, STA 2 may be set with a NAV by a frame for obtaining a TXOP transmitted before STA 1 allocates a shared TXOP. That is, STA 2 may be set to the NAV by receiving a frame transmitted before STA 1 transmits the modified MU-RTS frame. Alternatively, STA 2 may receive a frame sent from another STA during the same TXOP and set the NAV before STA 2 receives a modified MU-RTS frame addressed to itself. Alternatively, STA 2 may be set to NAV based on the modified MU-RTS frame addressed to itself. That is, since STA 2 receives at least the modified MU-RTS frame when using the shared TXOP, the NAV may be set. Thus, STA 2 may have difficulty transmitting frames using the shared TXOP.

Thus, according to an embodiment of the present invention, STAs receiving TXOP sharing may transmit frames independent of the NAV. For example, STAs receiving a TXOP share may transmit frames during the shared TXOP regardless of the NAV. For example, STAs receiving TXOP sharing may transmit frames even if they are set with a NAV (or the NAV is greater than 0). According to a more specific embodiment, the NAV may be limited to an intra-BSS NAV at this time. For example, STAs receiving TXOP sharing may transmit frames independent of the NAV within the BSS. Further, STAs receiving TXOP sharing may not be able to transmit frames when set with the basic NAV. Alternatively, the STA receiving the TXOP sharing may transmit the frame regardless of the frame transmitted by the associated AP or the NAV set by the PPDU. For example, when the NAV of an STA receiving TXOP sharing is set by a frame transmitted by the STA instead of an associated AP, it may not be possible to transmit the frame during the shared TXOP.

That is, when receiving the TXOP sharing, the STA may transmit the PPDU regardless of the NAV set within the shared TXOP. Specifically, when the AP transmits a trigger frame (a modified MU-RTS frame or MU-RTS TXS trigger frame) for sharing the TXOP, the NAV is set by the AP within the shared TXOP. In this case, the STA receiving the TXOP share may not be able to transmit the PPDU due to the NAV set within the shared TXOP. Thus, the STA receiving the TXOP share may ignore the NAV set by the AP sharing the TXOP within the shared TXOP to transmit the PPDU.

In the present invention, a so-called frame may be replaced with a PPDU including the frame and applied in the present invention.

Further, in this case, a frame transmitted by an STA receiving TXOP sharing regardless of NAV may correspond to a case of being transmitted after an SIFS has passed since a previous PPDU.

According to another embodiment, when receiving a frame transmitted by a STA shared by TXOPs, a NAV may be considered in case the frame is transmitted after a previous PPDU passes through a PIFS.

Referring to fig. 20, sta 2 may set the NAV based on the MU-RTS frame or the modified MU-RTS frame. For example, an intra-BSS NAV may be set. Alternatively, STA 2 may set the NAV based on the intra-BSS frame. Alternatively, STA 2 may set the NAV based on frames transmitted by the associated AP. In this embodiment, the so-called NAV may be a generic name of the NAV as described above. STA 1 may share a TXOP with STA 2. STA 2 may receive TXOP sharing through the modified MU-RTS frame. When transmitting frames within the shared TXOP, STA 2 may transmit frames independent of the NAV. At this time, according to an embodiment, the transmitted frame may be a frame that is transmitted immediately after a CTS frame that is transmitted immediately after the received modified MU-RTS frame. According to another embodiment, the frame transmitted at this time may be a frame transmitted immediately after the received modified MU-RTS frame. Further, according to an embodiment, the frame transmitted by STA 2 may be a frame to be transmitted to the STA that transmitted the modified MU-RTS frame. That is, the RA field of the transmitted frame may be set to the value of the TA field of the received modified MU-RTS frame. Alternatively, the RA field of the frame to be transmitted may be set to the MAC address of the AP. According to another embodiment, the frame transmitted by STA 2 may be a frame to be transmitted to STA 3. Further, immediately transmitting the frame may mean a case where a transmission start time point of a PPDU including the frame is located at a position after SIFS from the end of a previous PPDU.

The embodiment of fig. 21 may be a method for solving the problems described in fig. 19 and 20. Therefore, what has been described above may be omitted.

According to an embodiment of the present invention, in order to solve the problem of difficulty in transmitting frames during a shared TXOP in consideration of a NAV, a sequence of frames may be made continuous to satisfy a condition of transmitting a response irrespective of the NAV.

In accordance with an embodiment of the present invention, a STA receiving a TXOP share may send a CTS-to-self (self-cleaning send) frame in response to a modified MU-RTS frame. The CTS-to-self frame may be a CTS frame in which the RA field is set to the MAC address of the STA transmitting the CTS-to-self frame. In this case, when the STA sharing the TXOP receives a frame including the MAC address of the STA receiving the TXOP sharing after transmitting the modified MU-RTS frame, the STA sharing the TXOP may determine that the allocation of the shared TXOP has been successfully performed.

Referring to fig. 21, STA 2 may receive a modified MU-RTS frame from STA 1. Further, STA 2 may send a CTS-to-self frame immediately after the modified MU-RTS frame. That is, STA 2 may transmit the CTS frame by setting the RA field of the CTS frame to the MAC address of STA 2. In this case, the CTS-to-self frame transmitted by STA 2 may be considered as a frame addressed to itself and requesting an immediate response. Alternatively, STA 2 may consider the transmitted CTS-to-self frame as a frame addressed to itself and requesting an immediate response. Therefore, even if the NAV is set, STA 2 can transmit a frame immediately after the CTS-to-self frame.

According to an embodiment of the present invention, the RA field of the CTS frame, which is transmitted as a response to an RTS frame or MU-RTS frame, may be set to the TA field value of the RTS frame or MU-RTS frame or to a value in the TA field value that sets an Individual/Group (indivisual/Group) bit to 0. However, in order to transmit the CTS-to-self frame as shown in fig. 21, a method for setting the RA field of the additional CTS frame may be defined. For example, the RA field of the CTS frame, which is sent in response to the modified MU-RTS frame, may be set to the MAC address of the STA that sent the CTS frame.

In accordance with an embodiment of the present invention, STAs receiving TXOP sharing may perform recovery (recovery) within the shared TXOP. That is, when a STA receiving the TXOP share fails to transmit a frame within the shared TXOP, the STA may perform recovery. For example, when a STA receiving a TXOP share fails to transmit a frame within the shared TXOP, the STA may transmit the frame after the PIFS. In accordance with an embodiment of the present invention, the TXOP holder may perform a resume. In addition, when the TXOP holder performs TXOP sharing, the STA receiving the TXOP sharing may perform recovery. That is, when 1) an STA that is neither a TXOP holder nor a TXOP responder becomes an STA that receives TXOP sharing, it may perform recovery. In addition, when the STA receiving the TXOP sharing transmits a first frame other than the CTS frame after receiving the modified MU-RTS frame, if the frame other than the CTS frame fails, a recovery operation may also be performed. For example, when the first transmitted frame in the sequence fails, the TXOP holder may not perform a recovery operation, in which case the TXOP holder may not obtain the TXOP. However, when a STA receiving the TXOP share fails to transmit a first frame other than the CTS frame in the shared TXOP, it may also perform a recovery operation.

Referring to fig. 21, sta 2 may transmit the UL frame illustrated in the drawing and perform a recovery operation when the UL frame fails. That is, when STA 2 transmits an UL frame and fails to receive the DL frame illustrated in the drawing, STA 2 may retransmit the frame. In this case, the retransmitted frame may be transmitted after passing through the PIFS from the end of the PPDU including the failed UL frame shown in the figure. Further, it may be determined during recovery whether the channel is in an idle state. Further, in the recovery operation performed by the STA receiving the TXOP sharing, only the physical CS may be considered without considering the virtual CS.

As described in fig. 19, whether or not it is a modified MU-RTS frame may be determined based on the number of user information fields. However, the trigger frame defined in the 802.11ax standard may be designed without regard to the functional extension of the subsequent standard. Thus, for example, the common information field shown in (b) of fig. 16 may not have a signaling space enough to include an extended function. Thus, according to an embodiment of the present invention, the user information field including the preset AID12 subfield value may have a format different from that shown in (c) of fig. 16. Further, the user information field including the preset AID12 subfield value may include information corresponding to all recipients or one or more recipients of the trigger frame including the user information field. For example, the user information field including the preset AID12 subfield value may include at least one piece of information of PHY version ID, bandwidth extension, bandwidth, spatial reuse, and U-SIG reserved bits. Further, the preset AID12 subfield value may be based on a value not assigned to the actual AID. The preset AID12 subfield value may be 12 LSBs of the value to which the actual AID is not assigned. For example, the preset AID12 subfield value may be 2007.

Furthermore, the above-described extended functions may include, for example, a widened bandwidth. For example, the bandwidth may extend from a maximum of 160MHz to a maximum of 320MHz. Further, the extension function may include information for generating the U-SIG field.

Thus, according to an embodiment of the invention, the modified MU-RTS frame may include a user information field including an AID12 subfield value preset as described above to use extended functionality within the modified MU-RTS frame or the shared TXOP.

According to an embodiment of the present invention, the modified MU-RTS frame may not include any user information field, or may include only a user information field including the AID12 subfield value preset as described above as the user information field. That is, when the received trigger frame does not include any user information field or includes only a user information field including the AID12 subfield value preset as described above as the user information field, the above trigger frame may be judged as a modified MU-RTS frame. Alternatively, the received MU-RTS frame may be determined as a modified MU-RTS frame when it does not include any user information field or only includes a user information field including an AID12 subfield value preset as described above as the user information field. In this case, the STA receiving the TXOP sharing may be indicated by the RA field of the trigger frame.

Referring to fig. 22, a type subfield of a modified MU-RTS frame may be set to MU-RTS. Further, the modified MU-RTS frame may include one user information field, in which case the AID12 subfield included in the user information field may be set to a predetermined value. In this case, the predetermined value may be a value that is not assigned to the AID. Further, the predetermined value may be different from a value of 12 LSBs of the AID of the STA in which the RA field value of the modified MU-RTS frame is the MAC address. For example, the predetermined value may be 2007. Alternatively, the modified MU-RTS frame may not include any user information fields. That is, an STA that receives a trigger frame may determine the trigger frame as a modified MU-RTS frame when the trigger frame does not include any user information field or includes only a user information field including an AID12 subfield of a predetermined value in the case where the type of the trigger frame is set as the MU-RTS frame.

According to an embodiment of the invention, the STA may release (reset) the set NAV. For example, when the NAV is set based on the RTS frame or the MU-RTS frame, the NAV may be released. More specifically, when the NAV is set based on the RTS frame or the MU-RTS frame, the NAV may be released if PPDU reception is not successfully started within a predetermined period of time. Such an operation may be referred to as a NAV timeout or NAVTimeout. The predetermined time period may be a NAVTimeout period or a NAV timeout period. The NAVTimeout period may begin when a PHY-rxend.indication primitive corresponding to an RTS frame or MU-RTS frame is received.

In an embodiment of the present invention, the case of setting the NAV based on the RTS frame or the MU-RTS frame may be the case of performing the latest NAV update based on the RTS frame or the MU-RTS frame. If the duration information received from the RTS frame or the MU-RTS frame is greater than the current NAV value of the STA, the STA may set or update the NAV based on the RTS frame or the MU-RTS frame. The duration information may be obtained based on a duration/ID field included in the MAC header or a TXOP duration or TXOP field included in the preamble of the PPDU.

Further, in an embodiment of the present invention, a PHY-rxstart.indication primitive may be received when PPDU reception is successfully started. Alternatively, a PHY-rxstart.indication primitive may be issued when PPDU reception is successfully started. The PHY-rxstart.indication primitive may be transmitted from PHY to MAC. For example, a PHY-rxstart.indication primitive may be generated when the PHY receives a valid (valid) start of a PPDU. Further, the case where the valid start of the PPDU is received may be the case where a valid PHY header is received. Further, a PHY-rxstart.indication primitive may be generated after the PPDU format is determined. When generating the PHY-rxstart.indication primitive, the PHY may keep the physical medium in an occupied state during the length of the PPDU or the length indicated by the preamble of the PPDU. If the PHY-rxstart.indication primitive is generated, the PHY may maintain the physical medium in an occupied state during the length of the PPDU or the length indicated by the preamble of the PPDU even if the PPDU fails to be received halfway. Further, when PPDU reception ends, PHY-rxend.

According to embodiments of the invention, the NAV timeout period as described above may be based on a response time for an RTS frame or MU-RTS frame. That is, when the response to the RTS frame or MU-RTS frame is a CTS frame, the NAV timeout period may be based on the CTS frame time. The CTS frame Time may be denoted as cts_time. Alternatively, the response Time for the RTS frame or MU-RTS frame may be denoted cts_time. In this case. The response time to the RTS frame or MU-RTS frame may be the length of the PPDU that includes the response.

According to an embodiment, the NAV timeout period may be based on at least one of the following.

1)CTS_Time

2)aSIFSTime

3)aRxPHYStartDelay

4)aSlotTime

According to an embodiment, cts_time may be calculated based on a preset rate. That is, cts_time may be the length of CTS frame calculated based on a preset rate. Alternatively, that is, the cts_time may be the length of a PPDU including a CTS frame calculated based on a preset rate. For example, the preset rate may be 6Mbps. For example, cts_time may be calculated based on a data rate of 6Mbps. Alternatively, the preset rate may be a rate of an RTS frame or MU-RTS frame setting the NAV. Alternatively, the preset rate may be a ratio indicated by an RTS frame or MU-RTS frame setting the NAV.

According to an embodiment, aSIFSTime may be SIFS length. For example, in the case of operation in the 2.4GHz band, aSIFSTime may be 10us. For example, in the case of operation in the 5GHz band or the 6GHz band, the aSIFSTime may be 16us.

According to an embodiment, aRxPHYStartDelay may be the delay required from the start of the PPDU to the receiver generating the PHY-rxstart. For example, aRxPHYStartDelay may be the time taken from the start of the PPDU to determining the PPDU format. For example, aRxPHYStartDelay may be different according to PPDU format. For non-HT PPDU, aRxPHYStartDelay it may be 20us. Further, the HT PPDU, aRxPHYStartDelay for having the HT mixed format may be 28us. In addition, HT PPDU, aRxPHYStartDelay for HT-greenfield format may be 24us. Furthermore, for VHT PPDU, aRxPHYStartDelay may be (36+4 (maximum possible value supported for n_vht-LTF) +4) us. N_VHT-LTF may be the number of VHT-LTFs. Further, 32us may be used for HE SU PPDU or HE TB PPDU, aRxPHYStartDelay. Further, SU PPDU, aRxPHYStartDelay may be 40us for HE ER. Further, the MU PPDU, aRxPHYStartDelay for HE may be (32+4×n_he-SIG-B) us. The N_HE-SIG-B may be the number of OFDM symbols of the HE-SIG-B field. Further, 32us may be for the EHT MU PPDU or the EHT TB PPDU, aRxPHYStartDelay.

According to an embodiment, the NAV timeout period may be ((2 x asifstime) + (cts_time) +arxphystartdelay+ (2 x alslottime)).

According to an embodiment of the present invention, the RTS frame may be a frame indicating a CTS frame. Alternatively, the RTS frame may be a frame indicating a CTS frame from a single STA. The RTS frame may include a frame control field, a duration field, a RA field, a TA field, and an FCS field. The duration field may include time information for the STA receiving the duration field to set the NAV. Further, the RA field may include the address of the desired immediate responder (intended immediate recipient). For example, when the RA field included in the RTS frame received by the STA is the address of the STA, the STA may respond with a CTS frame for the RTS frame. Further, it may be determined that the frame is an RTS frame based on a frame control field included in the frame. For example, it may be determined that the frame is an RTS frame based on a type subfield and a subtype subfield included in a frame control field included in the frame. For example, when the type subfield is 01 (B3B 2) and the subtype subfield is 1011 (B7B 6B 5B 4), it may be indicated that the frame including the type subfield and the subtype subfield is an RTS frame. For example, the RTS frame may be a control frame.

The CTS frame may include a frame control field, a duration field, an RA field, and an FCS field. In this case, the duration field may include time information required for the STA receiving the duration field to set the NAV. For example, when the type subfield is 01 (B3B 2) and the subtype subfield is 1100 (B7B 6B 5B 4), it may be indicated that the frame including the type subfield and the subtype subfield is a CTS frame. For example, the CTS frame may be a control frame.

Referring to the first sequence of fig. 23, there may be STA 1, STA 2, and STA 3. Further, STA 1 may send an RTS frame or MU-RTS frame to STA 2. For example, if the RA field of the RTS frame or MU-RTS frame is set to the address of STA 2, the RTS frame or MU-RTS frame may be transmitted to STA 2. Alternatively, the MU-RTS frame may be transmitted to STA 2 if the user information field included in the MU-RTS frame indicates STA 2. If STA 2 successfully receives an RTS frame or MU-RTS frame, STA 2 may respond with a CTS frame. In this case, the STA 2 may respond based on the carrier sense result. Further, when STA 3 receives the RTS frame or the MU-RTS frame, STA 3 may set the NAV based on duration information included in the RTS frame or the MU-RTS frame or duration information included in a PPDU including the RTS frame or the MU-RTS frame. Further, when STA 1 successfully receives the CTS frame transmitted by STA 2, STA 1 may transmit a frame to STA 2. Further, after setting the NAV, the STA 3 may receive a CTS frame transmitted from the STA 2 or a frame transmitted to the STA 2 by the STA 1. In this case, the STA 3 may receive the PHY-rxstart.indication primitive within the NAV timeout period. Therefore, the NAV set by STA 3 may not be released.

Referring to the second sequence of fig. 23, there may be STA 1, STA 2, and STA 3. Further, STA 1 may send an RTS frame or MU-RTS frame to STA 2. STA 2 may not be able to respond with a CTS frame if STA 2 did not successfully receive an RTS frame or a MU-RTS frame. Alternatively, although STA 2 successfully receives the RTS frame or the MU-RTS frame, STA 2 may not respond with a CTS frame based on the carrier sense result. In this case, the frame sequence transmitted from STA 1 to STA 2 may not be consecutive.

Further, when STA 3 receives the RTS frame or the MU-RTS frame, STA 3 may set the NAV based on duration information included in the RTS frame or the MU-RTS frame or duration information included in a PPDU including the RTS frame or the MU-RTS frame. Further, after setting the NAV, the STA 3 may not be able to receive the CTS frame transmitted from the STA 2 or the frame transmitted from the STA 1 to the STA 2. In this case, STA 3 may not receive the PHY-rxstart.indication primitive within the NAV timeout period. Thus, the NAV set by STA 3 may be released. Therefore, even if the sequence is discontinuous, the problem that the STA 3 cannot access the channel because it holds the NAV can be solved.

Referring to fig. 24, as described above, STA 1 may perform TXOP sharing with STA 2. For example, STA 1 may be an STA providing TXOP sharing, and STA 2 may be an STA receiving TXOP sharing. STA 1 may send the first frame of the sequence to STA 2. Referring to fig. 24, the first frame of the sequence that STA 1 transmits to STA 2 may be a MU-RTS frame. Further, a CTS frame may be transmitted in response to a MU-RTS frame.

For example, a CTS frame may be transmitted from an STA including STA 2. STA 1 may obtain the TXOP. Further, STA 3 may not successfully receive the MU-RTS frame and CTS frame. STA 1 may send a modified MU-RTS frame to STA 2. That is, STA 1 may perform TXOP sharing with STA 2. In addition, STA 3 may successfully receive the modified MU-RTS frame. Thus, STA 3 may set the NAV based on the modified MU-RTS frame. In this case, STA 3 may set the NAV based on the MU-RTS frame. Further, according to the TXOP sharing sequence described above, STA 2 may transmit 1) a CTS frame for a modified MU-RTS frame, and may transmit a frame immediately after transmitting the CTS frame. Alternatively, for a modified MU-RTS frame, STA 2 may 2) send the frame without sending a CTS frame. In addition, STA 3 may fail to receive a frame or PPDU from STA 2. For example, STA 3 may exist in a hidden (hidden) position with respect to STA 2. For example, the power transmitted by STA 2 may not be sufficient for reception by STA 3. In this case, STA 3 may not be able to receive the PPDU during the NAV timeout period. This may be because the NAV timeout period is determined based on cts_time. That is, when STA 2 transmits a frame after transmitting a CTS frame, the NAV timeout period of STA 3 may end during which the frame is transmitted. Alternatively, when STA 2 transmits a frame without transmitting a CTS frame, since the length of the frame is likely to be greater than that of the CTS frame, the NAV timeout period of STA 3 may end during which the above frame is transmitted. Thus, STA 3 may release the NAV. If STA 3 releases the NAV, STA 3 may connect to the channel and may interfere with sequences during the shared TXOP.

Referring to fig. 25, when a TXOP is shared by an AP, another STA (third STA) other than the STA with which the AP shares the TXOP may not release the shared TXOP even though the STA shared the TXOP does not transmit a CTS frame or another frame for a predetermined time. The embodiment of fig. 25 may be used to solve the problems described with reference to fig. 23 to 24. Further, what has been described above may be omitted.

In particular, NAV timeout for releasing a TXOP may be allowed or not allowed based on whether a trigger frame (e.g., MU-RTS frame) sent from an AP is a modified MU-RTS frame or MU-RTS TXS trigger frame for sharing the TXOP. That is, whether to allow a NAV timeout for releasing the set TXOP for another STA that is not the set TXOP may be determined according to whether it is a conventionally set TXOP or whether all or a part of the set TXOP is shared by the AP.

For example, NAV timeout may be allowed when the NAV is set based on the MU-RTS frame, rather than based on a frame (modified MU-RTS frame or MU-RTS TXS trigger frame) that is used to share part or all of the set TXOPs. That is, when the STA sets the NAV based on the MU-RTS frame, if the MU-RTS frame is not a modified MU-RTS frame, the NAV may be released when PPDU reception is not successfully started during a NAV timeout period.

However, when the NAV is set by a modified MU-RTS frame or MU-RTS TXS trigger frame (which is a frame for sharing part or all of the set TXOP), the NAV timeout may not be allowed. That is, when the STA sets the NAV based on the MU-RTS frame, if the corresponding MU-RTS frame is a modified MU-RTS frame or MU-RTS TXS trigger frame for TXOP sharing, the STA cannot release the NAV even if PPDU reception is not successfully started during a NAV timeout period.

That is, if the most recently received frame for updating the NAV is a MU-RTS frame or a MU-RTS TXS trigger frame that is a modification of the frame for TXOP sharing, the STA cannot reset the NAV after expiration of the NAV timeout.

Whether the received MU-RTS frame is a modified MU-RTS frame may follow the embodiments described above. For example, whether the frame is a modified MU-RTS frame may be determined based on GI and HE-LTF type subfields included in the MU-RTS frame. For example, when the GI and HE-LTF type subfield values are 0, the MU-RTS frame including the GI and HE-LTF type subfields may not be a modified MU-RTS frame. Further, when the GI and HE-LTF type subfield values are not 0, the MU-RTS frame including the GI and HE-LTF type subfields may be a modified MU-RTS frame. For example, when the GI and HE-LTF type subfield values are 1 or 2, the MU-RTS frame including the GI and HE-LTF type subfields may be a modified MU-RTS frame.

According to the embodiment of the present invention, the problem described in fig. 24, that is, after the STA sets the NAV based on the modified MU-RTS frame, the STA can avoid interfering with the sequence of the shared TXOP by performing a NAV timeout operation, can be prevented.

Further, a terminal after the 802.11be standard (a terminal after a standard including the EHT standard) may perform the embodiment, while a terminal (HE STA) at the 802.11ax standard may not be able to perform the embodiment. Although the HE STA cannot perform this embodiment, the occurrence probability of the problem described by the above-described embodiment can be reduced.

Referring to fig. 25, there may be STA 1, STA 2, and STA 3. Further, STA 1 may send a MU-RTS frame to STA 2. For example, STA 1 may send a MU-RTS frame instead of a modified MU-RTS frame. However, STA 2, which is the intended recipient of the MU-RTS frame, may not respond to the MU-RTS frame. Therefore, STA 2 may not transmit the CTS frame. Further, STA 3 may set the NAV based on the MU-RTS frame. However, since STA 2 cannot transmit the CTS frame, STA 3 may not successfully start PPDU reception during the NAV timeout period. In this case, the STA 3 may release the set NAV based on the NAV timeout operation. This is because the frame that causes STA 3 to set the NAV is a MU-RTS frame, not a modified MU-RTS frame.

In addition, STA 1 may send a modified MU-RTS frame. In fig. 25, the previous frame of the modified MU-RTS frame may be omitted. STA 2, which is the intended recipient of the modified MU-RTS frame, may respond to the modified MU-RTS frame. Furthermore, STA 3 may set the NAV based on the modified MU-RTS frame. However, STA 3 may fail to receive the response sent by STA 2 for the modified MU-RTS frame. For example, the response sent from STA 2 may not have sufficient power for STA 3. For example, the reason may be that STA 3 and STA 2 are far apart from each other. In this case, STA 3 may not successfully start PPDU reception during the NAV timeout period. This is possible because STA 2 transmits a frame after transmitting a CTS frame after the modified MU-RTS frame. Alternatively, this may be because STA 2 sent a frame longer than the CTS frame after the modified MU-RTS frame. Alternatively, this may be because STA 2 transmitted a longer PPDU than the PPDU including the CTS frame after the modified MU-RTS frame. In this case, the STA 3 may not perform a NAV release operation based on the NAV timeout operation. This is because the frame that causes STA 3 to set the NAV is an MU-RTS frame that is a modified MU-RTS frame.

Fig. 26 is a diagram illustrating TXOP sharing and NAV timeout according to another embodiment of the present invention.

The embodiment of fig. 26 may be used to solve the problems described with reference to fig. 23 to 24. Further, what has been described above may be omitted.

According to an embodiment of the invention, the NAV timeout period may be determined differently based on whether the MU-RTS frame is a modified MU-RTS frame. For example, cts_time may be determined differently based on whether the MU-RTS frame is a modified MU-RTS frame. According to an embodiment, if the MU-RTS frame is a modified MU-RTS frame, the NAV timeout period may be longer than if the MU-RTS frame is not a modified MU-RTS frame. In this embodiment, if the MU-RTS frame is a modified MU-RTS frame, the NAV timeout period may be referred to as an extended NAV timeout period. The NAV timeout period and extended NAV timeout period described in fig. 23 may start at the same point in time. That is, it may start when a PHY-rxend. Indication primitive corresponding to a MU-RTS frame is received. The NAV timeout period described in fig. 23 may be a time based on the CTS frame time. For example, the NAV timeout period described in fig. 23 may be a time based on the time required to transmit a CTS frame at a rate of 6 Mbps.

According to an embodiment of the present invention, when the STA sets the NAV based on the modified MU-RTS frame, the NAV may be released if PPDU reception is not successfully started during the extended NAV timeout period. When the STA sets the NAV based on the modified MU-RTS frame, the NAV may not be released even if PPDU reception is not successfully started during the NAV timeout period as described in fig. 23.

Further, when the STA sets the NAV based on the MU-RTS frame that is not the modified MU-RTS frame, the NAV may be released when PPDU reception is not successfully started during the NAV timeout period as described in fig. 23.

According to embodiments of the present invention, the extended NAV timeout period may be determined based on length information included in the modified MU-RTS frame. For example, cts_time may be determined based on length information included in the modified MU-RTS frame. Alternatively, the extended NAV timeout period may be determined based on the length information included in the modified MU-RTS frame and the rate corresponding to the modified MU-RTS frame. For example, cts_time may be determined based on length information included in the modified MU-RTS frame and a rate corresponding to the modified MU-RTS frame. For example, the length information included in the modified MU-RTS frame may be included in the UL length subfield shown in fig. 16. In another embodiment, the length information included in the modified MU-RTS frame may be included in the user information field shown in fig. 16. More specifically, the length information included in the modified MU-RTS frame may be included in a user information field indicating STAs receiving TXOP sharing among the user information fields of fig. 16.

Further, the STA receiving the TXOP sharing may transmit a PPDU based on the length information included in the modified MU-RTS frame. For example, a STA receiving the TXOP share may transmit a first PPDU of the shared TXOP based on length information included in the modified MU-RTS frame. Alternatively, the STA receiving the TXOP sharing may transmit a first PPDU excluding the CTS frame of the shared TXOP based on the length information included in the modified MU-RTS frame. The first PPDU excluding the CTS frame sharing the TXOP may be a first PPDU subsequent to the PPDU including the CTS frame.

Referring to fig. 26, there may be STA 1, STA 2, and STA 3. Further, STA 1 may send a MU-RTS frame to STA 2. For example, STA 1 may transmit a MU-RTS frame that is not a modified MU-RTS frame. However, STA 2, which is the intended recipient of the MU-RTS frame, may not respond to the MU-RTS frame. Therefore, STA 2 may not transmit the CTS frame. Further, STA 3 may set the NAV based on the MU-RTS frame. However, since STA 2 does not transmit the CTS frame, STA 3 may not successfully start PPDU reception during the NAV timeout period. In this case, the STA 3 may release the set NAV based on the NAV timeout operation. This is based on the operation of having STA 3 set the frame of the NAV to be based on the NAV timeout period that is not determined for the MU-RTS frame of the modified MU-RTS. That is, since the frame for causing STA 3 to set the NAV is an MU-RTS frame that is not a modified MU-RTS, the NAV timeout period may be determined based on the time required to transmit the CTS frame.

In addition, STA 1 may send a modified MU-RTS frame. In fig. 26, the frame preceding the modified MU-RTS frame may be omitted. STA 2, which is the intended recipient of the modified MU-RTS frame, may respond to the modified MU-RTS frame. Furthermore, STA 3 may set the NAV based on the modified MU-RTS frame. However, STA 3 may fail to receive the response sent by STA 2 for the modified MU-RTS frame. For example, the response sent from STA 2 may not have sufficient power for STA 3. For example, the reason may be that STA 3 and STA 2 are far apart from each other. In this case, the STA 3 may not successfully start PPDU reception during the NAV timeout period shown in fig. 23. In this case, however, STA 3 may successfully start PPDU reception during the extended NAV timeout period. Thus, STA 3 may not perform a NAV timeout operation. When the NAV timeout period described in fig. 23 expires, the STA 3 may wait for the extended NAV timeout period without performing a NAV release operation because the frame for which the STA 3 sets the NAV is an MU-RTS frame that is a modified MU-RTS frame.

STA 1 may perform a recovery operation if STA 2, which received the modified MU-RTS frame, does not respond. Thus, PPDU reception may be successfully started before STA 3 performs a NAV timeout operation.

Alternatively, if STA 2, which received the modified MU-RTS frame, does not respond, the sequence of shared TXOPs may be interrupted. In this case, the STA 3 solves the problem that it cannot access a channel by unnecessarily setting the NAV without an actual frame change by performing the NAV timeout operation.

The problem that the scheduled STA that receives the sharing of a part or all of the TXOPs set by the AP in the TXOP sharing has difficulty in performing transmission due to the set NAV and its solution have been described with reference to fig. 20. A solution according to another embodiment will be described with reference to fig. 27. In the following description, the scheduled STA and the STA that is shared with the TXOP are the same STA and may be used confused with each other.

Fig. 27 is a diagram illustrating a case in which an STA and an AP apply a NAV when TXOP sharing is applied according to an embodiment of the present invention.

In TXOP sharing, the scheduled STAs may not set NAV. In particular, in TXOP sharing, the scheduled STAs may not set NAV based on a MU-RTS frame or a MU-RTS TXS trigger frame that is a modification of the MU-RTS frame for TXOP sharing settings. The STA receiving the MU-RTS frame for the TXOP sharing settings may not set the NAV based on the MU-RTS frame for the TXOP sharing settings. STAs scheduled by the MU-RTS frame for TXOP sharing settings may not set NAV based on the MU-RTS frame for TXOP sharing settings. Thus, when the STA receives the trigger frame and the trigger frame schedules TXOP sharing to the STA, the STA may not set the NAV based on the trigger frame. That is, the STA may set the NAV based on the received trigger frame according to whether the trigger frame is a trigger frame for sharing the TXOP. For example, if the received MU-RTS frame is a modified MU-RTS frame or MU-RTS TXS trigger frame for shared TXOP, the STA does not set a NAV based on the received MU-RTS frame. However, if the received MU-RTS frame is not a modified MU-RTS frame or a MU-RTS TXS trigger frame for the shared TXOP, the STA sets the NAV based on the received MU-RTS frame.

Further, in TXOP sharing, the scheduled STAs may not set NAVs based on frames received within the shared TXOP.

In this case, "within" the shared TXOP may indicate until the shared TXOP is terminated, even if the duration of the shared TXOP is not fully utilized. When the scheduled STA of the shared TXOP transmits the PPDU and the PPDU includes only frames that do not request an immediate response, the TXOP is terminated when the STA transmits the PPDU. Thus, "within a shared TXOP" may be from the time the TXOP share is set to the time the TXOP shared scheduled STA sends a PPDU that includes only frames that do not request immediate responses. In the case where the scheduled STA of the TXOP sharing signals the end of the shared TXOP, the shared TXOP may terminate. Thus, the "within shared TXOP" may be made from the time the TXOP sharing is set to the time the scheduled STA of the TXOP sharing signals the end of the shared TXOP. Further, "within a TXOP" may be a time after the shared TXOP duration has elapsed since the time the TXOP sharing was set. Alternatively, the shared TXOP may be terminated when the STA receiving the TXOP sharing (or the STA providing the TXOP sharing) transmits and receives signaling regarding termination of the shared TXOP. In this case, the duration of the shared TXOP and the duration of the AP for the shared TXOP (the TXOP obtained from the frame of the original AP) may be the same, or the duration of the shared TXOP may be shorter than the duration of the TXOP. Thus, even if the shared TXOP is terminated, the TXOP may not be terminated. That is, when the duration of the shared TXOP is the same as the duration of the TXOP, if the shared TXOP is terminated, the TXOP is also terminated together, however, when the duration of the shared TXOP is shorter than the duration of the TXOP, the TXOP may be maintained even if the shared TXOP is terminated.

In another particular embodiment, the "within shared TXOP period" may be from the time the TXOP sharing is set to the time after the duration of the shared TXOP has elapsed, even though the shared TXOP is terminated before the shared TXOP period.

As described above, in TXOP sharing, the scheduled STA may transmit frames independent of the NAV. That is, when a NAV (e.g., a NAV set by an intra-BSS PPDU) is set in a TXOP set by an AP, a scheduled STA may transmit the PPDU in a shared TXOP regardless of the set NAV. In other words, the STA receiving the TXOP share may ignore the NAV set by the frame transmitted by the STA sharing the TXOP within the shared TXOP. In this case, the shared TXOP may terminate before the period set by the MU-RTS frame. That is, within the shared TXOP, STAs receiving the TXOP sharing may cease sharing of the TXOP by sending signaling requesting to cease sharing of the TXOP prior to the period set by the MU-RTS. For example, when receiving a share regarding all or a portion of the TXOP from the AP, the non-AP STA may stop the TXOP sharing by transmitting signaling for terminating the TXOP sharing to the AP to end the shared TXOP without a (pending) PPDU to be transmitted. The time point at which TXOP sharing is stopped may be one of a time point at which a non-AP STA transmits signaling for requesting stopping TXOP sharing or a time point at which a response frame for the corresponding signaling is received. In this case, signaling for sharing the TXOP may or may not request an immediate response. Further, in this case, since the non-AP STA stops sharing the TXOP before the period in which the TXOP set by the MU-RTS frame is shared, the non-AP STA may ignore the set NAV only until the point in time when the sharing of the TXOP is terminated.

In this case, STAs that set TXOP sharing may also transmit frames independent of the NAV. In the embodiment of fig. 27, a first STA (STA 1) transmits a MU-RTS frame for TXOP sharing settings to a second STA (STA 2). In this case, the first STA (STA 1) may be an AP. The second STA (STA 2) receives the MU-RTS frame for the TXOP sharing setting and transmits a CTS frame in response to the MU-RTS frame for the TXOP sharing setting. The second STA (STA 2) may perform frame exchange within the shared TXOP. The first STA (STA 1) may set the NAV based on a frame transmitted from the second STA (STA 2) or a frame transmitted to the second STA (STA 2). For example, within the shared TXOP, the second STA (STA 2) may perform frame exchanges with the third STA (STA 3). In this case, the first STA (STA 1) may set the NAV based on a frame transmitted by the third STA (STA 3) to the second STA (STA 2). Further, the first STA (STA 1) may set the NAV based on a frame transmitted from the second STA (STA 2) to the third STA (STA 3). As such, when the first STA (STA 1) sets the NAV, it may be difficult to transmit a frame within the TXOP to which the shared TXOP is allocated. For example, when the first STA (STA 1) is to transmit a frame after termination of the shared TXOP, the first STA (STA 1) may not be able to transmit the frame due to the NAV set within the shared TXOP. Specifically, when the PPDU transmitted in the shared TXOP includes a frame that is not a frame that causes an immediate response from the first STA (STA 1), the first STA (STA 1) may not transmit the frame due to the set NAV.

The STA having set TXOP sharing may transmit frames within the TXOP obtained by the STA regardless of the NAV. In another particular embodiment, STAs that set TXOP sharing may transmit frames within the acquired TXOP starting at the time when the shared TXOP is terminated, regardless of the NAV. The STA that sets the TXOP sharing may be an STA or a TXOP holder that transmits a MU-RTS frame for setting the TXOP sharing.

In this case, as described above, the shared TXOP may be terminated prior to the period set by the MU-RTS frame. For example, within a shared TXOP, STAs receiving the TXOP sharing may cease sharing of the TXOP by sending signaling requesting to cease TXOP sharing prior to a period set by the MU-RTS. For example, when receiving a share for all or a portion of a TXOP from an AP, a non-AP STA may stop the TXOP sharing by transmitting signaling to the AP to terminate the TXOP sharing to terminate the shared TXOP without a PPDU to be transmitted (or to be processed). The time point at which TXOP sharing is stopped may be one of a time point at which a non-AP STA transmits signaling for requesting stopping TXOP sharing or a time point at which a response frame for the corresponding signaling is received. In this case, signaling for sharing the TXOP may or may not request an immediate response. Further, in this case, since TXOP sharing is stopped before a period in which the TXOP set by the MU-RTS frame is shared, the AP may ignore the NAV set by the AP based on the PPDU transmitted and received by the non-AP STA from a point in time when the TXOP sharing is terminated.

In the above-described embodiments, the STA having set the TXOP sharing to transmit the frame irrespective of the NAV may mean that the frame is transmitted in the TXOP sharing irrespective of the NAV set based on the frame exchanged by the scheduled STA. Because when an STA that has set TXOP sharing transmits a frame in TXOP sharing regardless of a NAV set based on frames that the scheduled STA does not exchange, frame exchange of other STAs may be interfered. Further, the STA may determine whether or not to be a frame exchanged by the scheduled STA in TXOP sharing based on the MAC header of the frame. In particular, the STA may determine whether or not to be a frame exchanged by a scheduled STA in TXOP sharing based on an address field of the frame. The address field may include at least one of an RA field, a TA field, and a BSSID field. For example, when one of the address fields of the frame indicates the MAC address of the STA, the STA may determine to be a frame exchanged by the scheduled STA in TXOP sharing. Further, the STA may determine whether or not to be a frame exchanged by the scheduled STA in TXOP sharing based on a preamble of a PPDU including the frame. Further, the STA may determine whether to be a frame exchanged by the scheduled STA in the TXOP sharing based on at least one of a BSS color and an STA ID included in a preamble of a PPDU including the frame. When the preamble of the PPDU includes a BSS color of a BSS to which the scheduled STA shared by the TXOPs belongs and the preamble of the PPDU includes an STA ID corresponding to the scheduled STA shared by the TXOPs, the STA may determine a frame included in the PPDU as a frame exchanged by the scheduled STA. In this case, the STA ID may be a value set based on the AID of the STA.

In another particular embodiment, STAs set up for TXOP sharing may use only a physical CS (e.g., CCA) as a CS when transmitting frames independent of the NAV. Thus, the STA may not perform virtual CS.

In this specification, the setting of the NAV may be used with the updating of the NAV. Further, in the present specification, the NAV may include at least one of an intra-BSS NAV and a basic NAV. Further, if the type of NAV is not specifically described, the NAV may represent an intra-BSS NAV. Further, in the present specification, the STA setting the NAV based on a specific frame may include setting the NAV based on a PPDU including the frame. Thus, in this specification, the STA not setting the NAV based on a particular frame may include not setting the NAV based on a PPDU including the frame.

The MU-RTS frame for setting TXOP sharing may use a MAC address (e.g., RA field) or a user information field to indicate the scheduled STA of the TXOP. Setting the NAV based on the duration information of the frame or PPDU may indicate that the most recently set NAV is set based on the duration information of the frame or PPDU.

In another particular embodiment, the duration/ID field of a frame transmitted within a shared TXOP or a TXOP of a PPDU including the frame may be set based on the shared TXOP. Specifically, the duration/ID field of a frame transmitted within the shared TXOP or the TXOP of a PPDU including the frame may not be allowed to be set to exceed the shared TXOP. Thus, it is possible to prevent a problem that a STA having set a shared TXOP cannot transmit a frame even after the shared TXOP is terminated.

That is, when a TXOP set by an AP is shared to an STA through a trigger frame, duration information (e.g., a duration/ID field) included in a frame (e.g., PPDU) transmitted within the shared TXOP may be set based on the shared TXOP. Specifically, the TXO of frames that are not allowed to be transmitted within the shared TXOP is set to be greater than the shared TXOP. Accordingly, the TXOP of the PPDU transmitted to the AP setting the TXOP or the third STA for P2P communication within the shared TXOP should end the same as or earlier than the shared TXOP. Accordingly, the termination time point of the duration indicated by the duration information included in the PPDU may be the same as or earlier than the termination time point of the shared TXOP. In other words, when a part or all of the TXOP set by the AP is shared to a specific STA, the TXOP of the PPDU transmitted by the specific STA cannot exceed the shared TXOP and must expire before it. Therefore, the termination time point of the length (or TXOP) of the PPDU transmitted to the AP or the third STA for P2P communication by the specific STA cannot be later than and must be before the termination time point of the shared TXOP. In this case, since the termination time point of the length (or TXOP) of the PPDU should be equal to or earlier than the termination time point of the shared TXOP, a value indicated by the duration information included in the PPDU may be set based on the shared TXOP.

In another particular embodiment, STAs that set the shared TXOP may not set a NAV based on frames exchanged by scheduled STAs that are shared by the TXOP.

Within the shared TXOP, STAs that set the shared TXOP may not transmit a trigger frame. This is because, when an STA having set a shared TXOP within the shared TXOP transmits a trigger frame, the frame triggered by the trigger frame may overlap with the frame exchange of the scheduled STA. Further, when an STA having set a shared TXOP within the shared TXOP transmits a trigger frame to a scheduled STA, the scheduled STA may need to transmit a response to the trigger frame. Thus, this may not be consistent with the purpose of setting the shared TXOP. In these embodiments, the trigger frame may include a MU-RTS frame for setting TXOP sharing. In these embodiments, after termination of the shared TXOP, the STA that set the shared TXOP may send a trigger frame.

In the above-described embodiments, the trigger frame that the STA having set the shared TXOP cannot transmit may be the remaining trigger frames except for the trigger frame of the scheduled STA shared only for the TXOP. Thus, STAs that set the shared TXOP may send trigger frames only to scheduled STAs within the shared TXOP. For example, STAs that set a shared TXOP may send MU-RTS frames for setting a TXOP share to extend the shared TXOP. In this case, the STA receiving the MU-RTS frame for setting TXOP sharing may start frame exchange without transmitting the CTS frame. Specifically, when only frame exchange with an STA that has set TXOP sharing is allowed in TXOP sharing, an STA that receives a MU-RTS frame for setting TXOP sharing may start frame exchange without transmitting a CTS frame.

In this specification, the operation performed during the shared TXOP may be an operation using the TXOP shared by scheduled STAs shared by the TXOP. The operations performed during the shared TXOP may be: the TXOP-shared scheduled STA transmits a frame in response to the MU-RTS frame for setting the TXOP sharing, or the TXOP-shared scheduled STA transmits a frame within the shared TXOP. In this case, the response frame for the MU-RTS frame for setting TXOP sharing may be a CTS frame.

Signaling for TXOP sharing operations will be described. The STA may signal whether it can operate as a scheduled STA for TXOP sharing. In this case, the STA may signal through the EHT capability element whether it may operate as a scheduled STA that is shared by the TXOPs. Further, the STA may use the (re) connection request frame or the probe request frame to transmit signaling indicating whether the STA can operate as a scheduled STA for TXOP sharing. An STA desiring to set TXOP sharing may transmit an MU-RTS frame for setting TXOP sharing only to STAs that are signaled to operate as scheduled STAs for TXOP sharing. Further, STAs desiring to set TXOP sharing may not transmit an MU-RTS frame for setting TXOP sharing to STAs signaled to operate as scheduled STAs that cannot be shared by the TXOPs.

Further, the MU-RTS frame may include information indicating whether the MU-RTS frame is a MU-RTS frame for setting TXOP sharing. Further, if the MU-RTS frame is a MU-RTS frame for setting TXOP sharing, the MU-RTS frame may indicate a mode of TXOP sharing. The mode of TXOP sharing may indicate to which STAs the TXOP shared scheduled STAs are able to send frames. For example, in the first mode, the scheduled STA of the TXOP sharing may transmit only the frame to the STA to which the TXOP sharing is set. Further, in the second mode, the scheduled STA of the TXOP sharing may transmit a frame or transmit a P2P frame to the STA to which the TXOP sharing is set. The first mode may be indicated if the value of the information indicating whether the MU-RTS frame is the MU-RTS frame used to set TXOP sharing is 1. Further, if the value of the information indicating whether the MU-RTS frame is the MU-RTS frame for setting TXOP sharing is 2, the second mode may be indicated. Further, if the value of the information indicating whether the MU-RTS frame is the MU-RTS frame for setting TXOP sharing is 0, it may be indicated that the MU-RTS frame is not the MU-RTS frame for setting TXOP sharing.

In the above embodiments, the GI and HE-LTF type subfields may indicate whether the MU-RTS frame is a MU-RTS frame for setting TXOP sharing. When the MU-RTS frame is a MU-RTS frame for setting TXOP sharing, the GI and HE-LTF type subfields may indicate a mode of TXOP sharing, as described above. In this case, the GI and HE-LTF type subfields may be referred to as TXOP shared mode subfields. The TXOP sharing mode subfield may be a subfield from bit 21B 20 to bit 22B 21 of the common information field of fig. 16.

A method of terminating TXOP sharing is described with reference to fig. 28.

Fig. 28 is an example illustrating STA-terminated TXOP sharing in accordance with an embodiment of the present invention.

The scheduled STA of the TXOP sharing may signal termination of the TXOP sharing. When the STA set with TXOP sharing receives the termination signaling of the TXOP sharing, the STA set with TXOP sharing may be a TXOP holder. In addition, when the STA set with TXOP sharing receives a termination signaling of the TXOP sharing, the STA set with TXOP sharing may transmit a frame or PPDU. Specifically, when the STA having set the TXOP sharing receives the termination signaling of the TXOP sharing, the STA having set the TXOP sharing may transmit a frame or PPDU even within the shared TXOP. Further, when the scheduled STA of the TXOP sharing signals the termination of the TXOP sharing, the scheduled STA of the TXOP sharing may not transmit any frame or any PPDU within the remaining shared TXOPs.

The scheduled STA of the TXOP sharing may signal termination of the TXOP sharing using an a-control subfield. Specifically, an SRS (single response scheduling) control subfield of the a-control subfield may signal termination of TXOP sharing. The STA that receives the SRS control subfield may respond with a PPDU that is not a TB PPDU for a frame including the SRS control subfield. Further, a length of the response PPDU to the frame including the SRS control subfield may be determined based on the SRS control subfield. Specifically, the STA that receives the SRS control subfield may set the length of the PPDU, which is a response to the frame including the SRS control subfield, to the length indicated by the SRS control subfield.

Fig. 28 (a) illustrates the format of the SRS control subfield. As described above, the SRS control subfield may include a field indicating a length of the PPDU as a response to the MAC frame including the SRS control subfield. In this case, this field may be referred to as a PPDU response duration field. The PPDU response duration field may indicate time in units of 4us. The length of the PPDU indicated by the PPDU response duration field may be a value x4us of the PPDU response duration field. Further, the PPDU response duration field may be an 8-bit field.

Further, the STA may signal the capability regarding the SRS control subfield. Specifically, the STA may signal whether or not the SRS control subfield can be received. Further, the STA may signal whether it may respond to a frame including an SRS control subfield. The STA may not transmit the SRS control subfield to the STA that has signaled that the operation on the SRS control subfield is not supported. The STA may transmit the SRS control subfield to the STA that has signaled support for operations with respect to the SRS control subfield.

Further, the SRS control field may include a field signaling termination of TXOP sharing. The field signaling termination of TXOP sharing may be referred to as a shared TXOP termination field. The shared TXOP termination field may be a 1-bit field. The shared TXOP termination field may indicate that TXOP sharing is terminated when the value of the shared TXOP termination field is 1. When the value of the shared TXOP termination field is 0, the shared TXOP termination field may indicate that TXOP sharing is not terminated. When the STA receives a QoS data frame or a QoS Null (Null) frame with a value of 1 for the shared TXOP termination field, the STA may determine that the TXOP sharing is terminated.

In another particular embodiment, a frame with a predetermined setting may signal termination of TXOP sharing. In this case, the frame having the predetermined setting may be a Qos null frame. In particular, the frame having the predetermined setting may be a QoS null frame excluding the a-control subfield. Further, the frame having the predetermined setting may be a QoS null frame excluding the SRS control subfield. The scheduled STA of the TXOP sharing may signal termination of the TXOP sharing by transmitting a frame with a predetermined setting. Further, when the STA set with TXOP sharing receives a frame with a predetermined setting, the STA set with TXOP sharing may determine that TXOP sharing is terminated.

In the case where the scheduled STA of the TXOP sharing transmits the termination signaling of the TXOP sharing, the STA set with the TXOP sharing may not receive the signaling. In this case, the scheduled STA of the TXOP sharing may determine that the TXOP sharing is terminated so that no frame is transmitted. In addition, the STA that sets the TXOP sharing may determine that the TXOP sharing is not terminated, and thus, does not transmit a frame.

In a specific embodiment, when a TXOP-shared scheduled STA that has transmitted a TXOP-shared termination signaling receives a response to the signaling, the TXOP-shared scheduled STA may determine that the TXOP sharing is terminated. In this case, the scheduled STA of the TXOP sharing may determine that the TXOP sharing is terminated so that no frame is transmitted. The response to the termination signaling shared by the TXOPs may be an immediate response. Further, the response to the termination signaling for TXOP sharing may include an ACK (acknowledgement). However, this embodiment can be applied only when the Ack Policy (Policy) of termination signaling shared by TXOPs is set to require an immediate response. Specifically, when an Ack policy of a termination signaling of TXOP sharing requires an immediate response, if a scheduled STA of TXOP sharing that transmitted the termination signaling of TXOP sharing receives a response to the signaling, the scheduled STA of TXOP sharing may determine that the TXOP sharing is terminated. When the Ack policy of the termination signaling of the TXOP sharing does not require an immediate response (e.g., no Ack), the scheduled STA of the TXOP sharing may determine that the TXOP sharing is terminated even in a case where the scheduled STA of the TXOP sharing that transmitted the termination signaling of the TXOP sharing does not receive a response to the signaling. In this case, the scheduled STA of the TXOP sharing may determine the TXOP sharing termination when transmitting termination signaling of the TXOP sharing. In addition, when the termination signaling transmission of the TXOP sharing fails, an error recovery operation may be performed. Specifically, the scheduled STAs shared by the TXOPs may perform error recovery operations. In addition, the STA set with TXOP sharing may perform an error recovery operation.

In fig. 28 (b), the first STA (STA 1) transmits an MU-RTS frame for TXOP sharing to the second STA (STA 2). In this case, the first STA (STA 1) may be an AP. The second STA (STA 2) receives the MU-RTS frame for the TXOP sharing setting and transmits a CTS frame in response to the MU-RTS frame for the TXOP sharing setting. Within the shared TXOP, the second STA (STA 2) may send termination signaling for the TXOP sharing to the first STA (STA 1) (a frame to STA1 and indicating termination). The first STA (STA 1) does not receive termination signaling (a frame to STA1 and indicating termination) for TXOP sharing. In this case, the first STA (STA 1) may determine that TXOP sharing is not terminated. As described above, the first STA (STA 1) or the second STA (STA 2) may perform an error recovery operation. After the error recovery operation, the second STA (STA 2) may send termination signaling (a frame addressed to STA1 and indicating termination) for TXOP sharing to the first STA (STA 1). The first STA (STA 1) may transmit an ACK (acknowledgement to STA 2) to the second STA (STA 2) as a response to termination signaling (a frame to STA1 and indicating termination) shared by the TXOPs. A second STA (STA 2) receiving the ACK (acknowledgement to STA 2) may determine that the TXOP sharing has terminated.

Even after termination of TXOP sharing, if an STA indication response of TXOP sharing is set, a scheduled STA of TXOP sharing may still transmit a frame.

As described above, the SRS control subfield may not be transmitted to the STA that is signaled not to support the operation regarding the SRS control subfield. When the termination of the TXOP sharing is signaled through the SRS control subfield, an STA that has signaled that the operation regarding the SRS control subfield is not supported may not receive the termination signaling of the TXOP sharing. Thus, the scheduled STA of the TXOP sharing may transmit an SRS control subfield signaling termination of the TXOP sharing to STAs that do not support operations with respect to the SRS control subfield. The SRS control subfield signaling the termination of the TXOP sharing may be an SRS control subfield having a value of 1 of the TXOP termination subfield. The scheduled STA shared by the TXOPs cannot transmit the SRS control subfield with the value 0 of the TXOP termination subfield to the STA that is signaled not to support the operation on the SRS control subfield. Further, only when the SRS control subfield is transmitted outside the shared TXOP, a restriction that the SRS control subfield cannot be transmitted to the STA that signals that the operation of the SRS control subfield is not supported may be applied.

The PPDU response duration subfield may be set to a reserved field when the SRS control subfield signals termination of TXOP sharing. All bits of the reserved field may be set to 0. The PPDU response duration subfield may indicate a length of a PPDU including a frame as a response to the frame including the SRS control subfield if the SRS control subfield does not signal termination of the TXOP sharing.

When the SRS control subfield signals termination of the TXOP sharing, the STA receiving the SRS control subfield may not transmit a response to the frame including the SRS control subfield. In another particular embodiment, when the SRS control subfield signals termination of the TXOP sharing, the STA receiving the SRS control subfield may transmit a response to the frame including the SRS control subfield regardless of information signaled by the SRS control subfield. In this case, the STA that receives the SRS control subfield may transmit the response PPDU regardless of the length of the response PPDU for the frame including the SRS control subfield, which is signaled by the SRS control subfield.

STAs that receive the SRS control subfield within the shared TXOP may not transmit a response to a frame including the SRS control subfield. In another particular embodiment, STAs that receive the SRS control subfield within the shared TXOP may transmit a response to a frame including the SRS control subfield independent of information signaled by the SRS control field. In this case, the STA that receives the SRS control subfield may transmit the response PPDU regardless of the length of the response PPDU for the frame including the SRS control subfield, which is signaled by the SRS control subfield.

Alternatively, the STA that receives the SRS control subfield within the shared TXOP may not respond based on the duration information (PPDU response duration subfield value) included in the SRS control subfield. For example, STAs receiving the SRS control subfield within the shared TXOP may respond irrespective of duration information (PPDU response duration subfield value) included in the SRS control subfield.

According to an embodiment of the invention, the modified MU-RTS frame may not be the first frame within the TXOP. For example, the TXOP holder may not send a modified MU-RTS frame, but send another frame to obtain the TXOP. Thus, the NAV may be set by a particular STA before setting the NAV based on the modified MU-RTS frame. That is, the STA may set the NAV based on frames transmitted before the modified MU-RTS frame in the TXOP. The above-described NAV timeout operation may be performed in the case where NAV setting is completed based on an RTS frame or a MU-RTS frame, however, by having a frame transmission before the modified MU-RTS frame in the TXOP, the case where NAV is set based on the RTS frame or the MU-RTS frame can be reduced. The modified duration information of the MU-RTS frame may not increase the TXOP.

Referring to fig. 29, the sta may receive a share for a part or all of the TXOP from the AP and, based thereon, transmit a PPDU within the shared TXOP.

Specifically, the STA may receive a trigger frame indicating uplink transmission from an Access Point (AP) (S29010). In this case, the trigger frame may be used to share a part or all of a transmission opportunity (TXOP) obtained by the AP to the STA, and when the trigger frame is used to share a part or all of the TXOP, the trigger frame may be referred to as a modified MU-RTS frame or MU-TXS trigger frame. In this case, the STA may identify whether the received frame is a frame for TXOP sharing through the type field of the trigger frame as described above.

Subsequently, the STA may transmit a PPDU to the AP and/or another STA within the shared TXOP based on the trigger frame (S29020). The PPDU may include duration information indicating a TXOP for transmitting the PPDU, and the duration information may be set based on the shared TXOP.

The termination time point of the duration indicated by the duration information may be the same as or end before the termination time point of the shared TXOP.

When a Network Allocation Vector (NAV) is set for a frame transmitted by an AP in a TXOP, a PPDU is transmitted in a shared TXOP regardless of the NAV.

When the NAV and the NAV timeout period indicating the end time of the NAV are set by the other STA in the shared TXOP based on the trigger frame, the NAV set by the other STA in the shared TXOP may not be released due to expiration of the NAV timeout period even if the NAV timeout period expires in the shared TXOP.

The trigger frame may include a subfield indicating whether or not the TXOP is shared through the trigger frame.

When the above-described subfield indicates sharing of the TXOP, a value of the subfield may indicate whether transmission and reception with another STA are possible within the shared TXOP.

The trigger frame may include a type field indicating a type of the trigger frame, and sharing for a part or all of the TXOPs may be set according to the type of the trigger frame based on the type field.

The description of the present invention has been given for illustrative purposes and those skilled in the art to which the present invention pertains will appreciate that it can be readily modified into other specific embodiments without altering the technical spirit or essential features of the present invention. Accordingly, it should be understood that the above-described embodiments are illustrative in all respects, rather than restrictive. For example, each constituent element described as a single form may be implemented discretely, and constituent elements described as scattered may be implemented in a combined type.

The scope of the invention is defined by the appended claims rather than by the description, and all changes or modification embodiments that come within the meaning and range of equivalency of the claims are intended to be embraced therein.

Claims

1. A Station (STA) of a wireless communication system, comprising:

a transceiver; and

a processor, controlling the transceiver,

wherein the processor:

receiving a trigger frame from an Access Point (AP) indicating an uplink transmission, wherein the trigger frame is used to share a portion or all of a transmission opportunity (TXOP) obtained by the AP to the STA, and

based on the trigger frame, a physical layer protocol data unit (PPDU) is transmitted to the AP and/or another STA within the shared TXOP,

wherein the PPDU includes duration information indicating a TXOP for transmitting the PPDU, and

wherein the duration information is set based on the shared TXOP.

2. The STA of claim 1, wherein,

the termination time point of the duration indicated by the duration information is the same as the termination time point of the shared TXOP.

3. The STA of claim 1, wherein,

The duration indicated by the duration information ends before a termination time point of the shared TXOP.

4. The STA of claim 1, wherein,

when a Network Allocation Vector (NAV) is set in a frame transmitted by the AP in the TXOP, the PPDU is transmitted in the shared TXOP regardless of the set NAV.

5. The STA of claim 1, wherein,

when a NAV is set by another STA within the shared TXOP based on the trigger frame and a NAV timeout period indicating an end time of the NAV, the NAV set by the other STA within the shared TXOP is not released due to expiration of the NAV timeout period even if the NAV timeout period expires within the shared TXOP.

6. The STA of claim 1, wherein,

the trigger frame includes a subfield indicating whether the TXOP is shared through the trigger frame.

7. The STA of claim 6, wherein,

when the subfield indicates that the TXOP is shared, a value of the subfield indicates whether transmission and reception with the other STA are possible within the shared TXOP.

8. The STA of claim 1, wherein,

The trigger frame includes a type field indicating a type of the trigger frame, and

the sharing of a part or all of the TXOP is set according to the type of the trigger frame based on the type field.

9. A method of transmitting a frame by a Station (STA) in a wireless communication system, the method comprising:

receiving a trigger frame from an Access Point (AP) indicating an uplink transmission, wherein the trigger frame is used to share a portion or all of a transmission opportunity (TXOP) obtained by the AP to the STA; and

the duration information is set based on the shared TXOP.

10. The method of claim 9, wherein,

11. The method of claim 9, wherein,

12. The method of claim 9, wherein,

when a Network Allocation Vector (NAV) is set in a frame transmitted by an AP in the TXOP, the PPDU is transmitted in the shared TXOP regardless of the set NAV.

13. The method of claim 9, wherein,

14. The method of claim 9, wherein,

15. The method of claim 14, wherein,

16. The method of claim 9, wherein