CN116711389A

CN116711389A - Method and apparatus for receiving BSR information in multilink operation of wireless LAN system

Info

Publication number: CN116711389A
Application number: CN202180087933.7A
Authority: CN
Inventors: 金丁起; 崔镇洙
Original assignee: LG Electronics Inc
Current assignee: LG Electronics Inc
Priority date: 2020-12-28
Filing date: 2021-06-07
Publication date: 2023-09-05

Abstract

A method and apparatus for receiving BSR information in a wireless LAN system are provided. Specifically, the receiving MLD receives DL frames from the transmitting MLD. The receiving MLD transmits UL frames to the transmitting MLD. The DL frame includes BSR information about the receiving MLD. BSR information about the receiving MLD is included in a buffer status subfield of the QoS control field. BSR information on the receiving MLD is traffic information on the receiving MLD, which is buffered in the transmitting MLD.

Description

Method and apparatus for receiving BSR information in multilink operation of wireless LAN system

Technical Field

The present specification relates to multilink operation in a Wireless Local Area Network (WLAN) system, and more particularly, to a method and apparatus for receiving BSR information for a receiving MLD.

Background

Wireless Local Area Networks (WLANs) have been improved in various ways. For example, the IEEE 802.11ax standard proposes an improved communication environment using Orthogonal Frequency Division Multiple Access (OFDMA) and downlink multi-user multiple input multiple output (DL MU MIMO) techniques.

The present specification proposes technical features that can be utilized in a new communication standard. For example, the new communication standard may be the very high throughput (EHT) standard currently in question. The EHT standard may use newly proposed increased bandwidth, enhanced PHY layer protocol data unit (PPDU) structure, enhanced sequences, hybrid automatic repeat request (HARQ) scheme, etc. The EHT standard may be referred to as the IEEE 802.11be standard.

In the new wireless LAN standard, an increased number of spatial streams may be used. In this case, in order to properly use the increased number of spatial streams, it may be necessary to improve signaling techniques in the WLAN system.

Disclosure of Invention

Technical problem

The present specification proposes a method and apparatus for receiving BSR information in a multilink operation of a WLAN system.

Technical proposal

Examples of the present specification propose a method for BSR information in a multi-link operation.

The present embodiment may be performed in a network environment supporting a next generation WLAN system (IEEE 802.11be or EHT WLAN system). The next generation wireless LAN system is a WLAN system enhanced from the 802.11ax system, and thus can satisfy backward compatibility with the 802.11ax system.

This embodiment may be performed in a receiving MLD.

The present embodiment proposes a method and apparatus for setting a format of buffer status information transmitted from a transmitting MLD (or AP MLD) to a receiving MLD (or non-AP MLD).

A receiving multi-link device (MLD) receives a Downlink (DL) frame from a transmitting MLD.

The receiving MLD transmits UL frames to the transmitting MLD.

The DL frame includes BSR information for the receiving MLD. BSR information for the receiving MLD is traffic information for the receiving MLD buffered in the transmitting MLD.

BSR information for the receiving MLD is included in a buffer status subfield of a quality of service (QoS) control field. The buffer status subfield is an AP PS buffer status subfield and is allocated to bits 8 to 15 of the QoS control field. That is, this embodiment proposes a method of transmitting MLD informing buffer status of receiving MLD by using AP PS buffer status subfield.

Advantageous effects

According to the embodiments set forth in the present specification, the buffer status of the non-AP MLD can be notified based on the previously defined QoS AP PS buffer status subfield, and there is an effect that the complexity of implementing the design of the buffer status information transmitted from the transmitting MLD (or AP MLD) to the receiving MLD (or non-AP MLD) can be reduced. Further, when the buffer status of the non-AP MLD is notified, a threshold may be set without notifying the queue size itself, and whether the threshold is exceeded is notified, thereby reducing the overhead of the beacon frame.

Drawings

Fig. 1 shows an example of a transmitting device and/or a receiving device of the present specification.

Fig. 2 is a conceptual diagram illustrating a structure of a Wireless Local Area Network (WLAN).

Fig. 3 illustrates a general link setup procedure.

Fig. 4 illustrates an example of a PPDU used in the IEEE standard.

Fig. 5 illustrates UL-MU based operation.

Fig. 6 illustrates an example of a trigger frame.

Fig. 7 illustrates an example of a common information field of a trigger frame.

Fig. 8 illustrates an example of subfields included in the per-user information field.

Fig. 9 depicts the technical features of the UORA scheme.

Fig. 10 illustrates an example of a PPDU used in the present specification.

Fig. 11 illustrates an example of a transmitting apparatus and/or a receiving apparatus of the modification of the present specification.

Fig. 12 shows an example in which an AP MLD notifies a non-AP MLD that there is buffer traffic for all links in a multi-link operation.

Fig. 13 shows an example of informing an AP MLD of buffering traffic for STA1 through a DL frame in a multilink operation.

Fig. 14 shows an example in which the AP MLD notifies the existence of buffer traffic for STA1 through a beacon frame in the multilink operation.

Fig. 15 shows an example in which the AP MLD notifies the existence of the buffered traffic of the non-AP MLD1 through a beacon frame in the multi-link operation.

Fig. 16 shows an example of notifying the AP MLD that there is buffering traffic for STAs 1 to 3 through a beacon frame in a multi-link operation.

Fig. 17 illustrates an example of an ML-BSR element including BSR information included in a beacon frame.

Fig. 18 shows an example of ML-BSR elements using method 1.

Fig. 19 shows an example of ML-BSR elements using method 2.

Fig. 20 illustrates an example of a format in which scaling factor information is additionally included in the ML-BSR element of fig. 18.

Fig. 21 illustrates an example of a format in which scaling factor information is additionally included in the ML-BSR element of fig. 19.

Fig. 22 shows an example of ML-BSR elements with a scaling factor for each non-AP MLD.

Fig. 23 shows an example of an ML-BSR element indicating whether a queue size exceeds a certain threshold.

Fig. 24 illustrates an example of a format in which threshold information is additionally included in the ML-BSR element of fig. 23.

Fig. 25 shows an example of ML-BSR element having threshold information for each non-AP MLD.

Fig. 26 shows an example of negotiating a threshold value based on a request/response frame.

Fig. 27 shows an example of negotiating a threshold based on an association request/response frame.

Fig. 28 shows an example of transmitting a recommendation threshold in a request frame.

Fig. 29 illustrates another example of an ML-BSR element including BSR information included in a beacon frame.

Fig. 30 shows another example of an ML-BSR element.

Fig. 31 shows another example of an ML-BSR element.

Fig. 32 shows an example in which an AP MLD notifies a non-AP MLD of the existence of a buffered service in a multi-link operation.

Fig. 33 illustrates an example of including a lower delay traffic indicator and transmitting the lower delay traffic indicator through a beacon frame.

Fig. 34 shows an example of transmission by including a lower delay traffic indicator in a DL frame transmitted to a corresponding non-AP MLD instead of a beacon.

Fig. 35 illustrates an example in which an AP MLD notifies BSR information for a non-AP MLD through a DL frame in a multi-link operation.

Fig. 36 illustrates another example in which an AP MLD notifies BSR information for a non-AP MLD through a DL frame in a multi-link operation.

Fig. 37 illustrates another example in which an AP MLD notifies BSR information about a non-AP MLD through a DL frame in a multi-link operation.

Fig. 38 shows an example of an HT control field.

Fig. 39 shows an example of an a control subfield.

Fig. 40 shows an example of a control subfield format.

Fig. 41 shows an example of a non-AP BSR (NMB) control subfield.

Fig. 42 shows an example of a format in which a scaling factor is added in the subfield of fig. 41.

Fig. 43 shows an example of an NMB control subfield including all the above information.

Fig. 44 shows the format of the BSR control subfield in the 802.11ax system.

Fig. 45 shows an example of an AP PS buffer status subfield.

Fig. 46 shows an example of an AP PS buffer status subfield including BSR information for a non-AP MLD.

Fig. 47 is a flowchart illustrating a procedure for transmitting BSR information in a multilink operation according to the present embodiment.

Fig. 48 is a flowchart illustrating a procedure for receiving BSR information in a multilink operation according to the present embodiment.

Detailed Description

In this specification, "a or B" may mean "a only", "B only" or "both a and B". In other words, in the present specification, "a or B" may be interpreted as "a and/or B". For example, in this specification, "A, B or C" may mean any combination of "a only", "B only", "C only" or "A, B, C".

Slash (/) or comma as used in this specification may mean "and/or". For example, "A/B" may mean "A and/or B". Thus, "a/B" may mean "a only", "B only" or "both a and B". For example, "A, B, C" may mean "A, B or C".

In the present specification, "at least one of a and B" may mean "a only", "B only", or "both a and B". In addition, in the present specification, the expression "at least one of a or B" or "at least one of a and/or B" may be interpreted as "at least one of a and B".

In addition, in the present specification, "at least one of A, B and C" may mean "a only", "B only", "C only", or "A, B and C in any combination. In addition, "at least one of A, B or C" or "at least one of A, B and/or C" may mean "at least one of A, B and C".

In addition, brackets used in this specification may mean "for example". Specifically, when indicated as "control information (EHT-signal)", it may represent that "EHT-signal" is proposed as an example of "control information". In other words, the "control information" of the present specification is not limited to the "EHT-signal," and the "EHT-signal" may be proposed as an example of the "control information. In addition, when indicated as "control information (i.e., EHT-signal)", it may also mean that "EHT-signal" is proposed as an example of "control information".

The technical features described separately in one drawing of the present specification may be implemented separately or may be implemented simultaneously.

The following examples of the present specification may be applied to various wireless communication systems. For example, the following examples of the present specification may be applied to a Wireless Local Area Network (WLAN) system. For example, the present description may be applied to the IEEE 802.11a/g/n/ac standard or the IEEE 802.11ax standard. In addition, the present specification can also be applied to the newly proposed EHT standard or IEEE 802.11be standard. Furthermore, the examples of the present specification can also be applied to a new WLAN standard enhanced from the EHT standard or the IEEE 802.11be standard. In addition, examples of the present specification may be applied to a mobile communication system. For example, it may be applied to a mobile communication system based on Long Term Evolution (LTE) depending on 3 rd generation partnership project (3 GPP) standards and LTE-based evolution. In addition, examples of the present specification may be applied to a communication system of a 5G NR standard based on a 3GPP standard.

Hereinafter, in order to describe technical features of the present specification, technical features applicable to the present specification will be described.

In the example of fig. 1, various technical features described below may be performed. Fig. 1 relates to at least one Station (STA). For example, STAs 110 and 120 of the present description may also be referred to as various terms such as mobile terminals, wireless devices, wireless transmit/receive units (WTRUs), user Equipment (UEs), mobile Stations (MSs), mobile subscriber units, or simply users. STAs 110 and 120 of the present description may also be referred to as various terms such as networks, base stations, node bs, access Points (APs), repeaters, routers, repeaters, and the like. STAs 110 and 120 of the present specification may also be referred to as various names such as a receiving device, a transmitting device, a receiving STA, a transmitting STA, a receiving apparatus, a transmitting apparatus, etc.

For example, STAs 110 and 120 may function as APs or non-APs. That is, STAs 110 and 120 of the present description may function as an AP and/or a non-AP.

In addition to the IEEE 802.11 standard, STAs 110 and 120 of the present specification may together support various communication standards. For example, communication standards based on 3GPP standards (e.g., LTE-A, 5G NR standards) and the like may be supported. In addition, the STA of the present description may be implemented as various devices such as a mobile phone, a vehicle, a personal computer, and the like. In addition, the STA of the present specification may support communication for various communication services such as voice call, video call, data communication, and self-driving (autonomous driving).

STAs 110 and 120 of the present description may include a Medium Access Control (MAC) compliant with the IEEE 802.11 standard and a physical layer interface for a radio medium.

STAs 110 and 120 will be described below with reference to sub-picture (a) of fig. 1.

The first STA 110 may include a processor 111, a memory 112, and a transceiver 113. The illustrated processor, memory, and transceiver may be implemented separately as separate chips, or at least two blocks/functions may be implemented by a single chip.

The transceiver 113 of the first STA performs a signal transmission/reception operation. Specifically, IEEE 802.11 packets (e.g., IEEE 802.11a/b/g/n/ac/ax/be, etc.) may be transmitted/received.

For example, the first STA 110 may perform operations expected by the AP. For example, the processor 111 of the AP may receive signals through the transceiver 113, process Received (RX) signals, generate Transmit (TX) signals, and provide control over signal transmission. The memory 112 of the AP may store signals (e.g., RX signals) received through the transceiver 113 and may store signals (e.g., TX signals) to be transmitted through the transceiver.

For example, the second STA 120 may perform operations expected by a non-AP STA. For example, the non-AP transceiver 123 performs a signal transmission/reception operation. Specifically, IEEE 802.11 packets (e.g., IEEE 802.11a/b/g/n/ac/ax/be packets, etc.) may be transmitted/received.

For example, the processor 121 of the non-AP STA may receive signals through the transceiver 123, process RX signals, generate TX signals, and provide control over signal transmission. The memory 122 of the non-AP STA may store signals (e.g., RX signals) received through the transceiver 123 and may store signals (e.g., TX signals) to be transmitted through the transceiver.

For example, the operations of the apparatus indicated as an AP in the description described below may be performed in the first STA 110 or the second STA 120. For example, if the first STA 110 is an AP, the operation of the device indicated as an AP may be controlled by the processor 111 of the first STA 110, and the related signals may be transmitted or received through the transceiver 113 controlled by the processor 111 of the first STA 110. In addition, control information related to the operation of the AP or TX/RX signals of the AP may be stored in the memory 112 of the first STA 110. In addition, if the second STA 120 is an AP, the operation of the device indicated as the AP may be controlled by the processor 121 of the second STA 120, and the related signal may be transmitted or received through the transceiver 123 controlled by the processor 121 of the second STA 120. In addition, control information related to the operation of the AP or TX/RX signals of the AP may be stored in the memory 122 of the second ST a 120.

For example, in the description described below, the operation of a device indicated as a non-AP (or user STA) may be performed in the first STA 110 or the second STA 120. For example, if the second STA 120 is non-AP, the operation of the device indicated as non-AP may be controlled by the processor 121 of the second STA 120, and the related signal may be transmitted or received through the transceiver 123 controlled by the processor 121 of the second STA 120. In addition, control information related to the operation of the non-AP or the TX/RX signal of the non-AP may be stored in the memory 122 of the second STA 120. For example, if the first STA 110 is non-AP, the operation of the device indicated as non-AP may be controlled by the processor 111 of the first STA 110, and the related signals may be transmitted or received through the transceiver 113 controlled by the processor 111 of the first STA 110. In addition, control information related to operation of the non-AP or TX/RX signals of the non-AP may be stored in the memory 112 of the first STA 110.

In the description described below, devices called (transmitting/receiving) STA, first STA, second STA, STA1, STA2, AP, first AP, second AP, AP1, AP2, (transmitting/receiving) terminal, (transmitting/receiving) device, (transmitting/receiving) apparatus, network, and the like may refer to STAs 110 and 120 of fig. 1 in an implied manner. For example, devices indicated (but not specifically numbered) (transmitting/receiving) STA, first STA, second STA, STA1, STA2, AP, first AP, second AP, AP1, AP2, (transmitting/receiving) terminal, (transmitting/receiving) device, (transmitting/receiving) apparatus, network, etc. may implicitly refer to STA 110 and 120 of fig. 1. For example, in the following examples, operations of various STAs transmitting/receiving signals (e.g., PPDUs) may be performed in the transceivers 113 and 123 of fig. 1. In addition, in the following examples, operations of various STAs generating TX/RX signals or performing data processing and calculation in advance for the TX/RX signals may be performed in the processors 111 and 121 of fig. 1. Examples of operations for generating TX/RX signals or performing data processing and computation in advance may include, for example: 1) An operation of determining/obtaining/configuring/calculating/decoding/encoding bit information of subfields (SIG, STF, LT F, data) included in the PPDU; 2) An operation of determining/configuring/obtaining time resources or frequency resources (e.g., subcarrier resources) for subfields (SIG, STF, LTF, data) included in the PPDU, etc.; 3) An operation of determining/configuring/obtaining a specific sequence (e.g., pilot sequence, STF/LTF sequence, additional sequence applied to SIG) for a subfield (SIG, STF, LTF, data) field included in the PPDU, etc.; 4) Power control operation and/or power save operation applied to the STA; and 5) operations related to determination/acquisition/configuration/decoding/encoding of an ACK signal, and the like. In addition, in the following examples, various information (e.g., information related to fields/subfields/control fields/parameters/power, etc.) used by various STAs to determine/obtain/configure/calculate/decode TX/RX signals may be stored in the memories 112 and 122 of fig. 1.

The foregoing apparatus/STA of sub-graph (a) of fig. 1 may be modified as shown in sub-graph (b) of fig. 1. Hereinafter, STA 110 and STA120 of the present specification will be described based on sub-diagram (b) of fig. 1.

For example, transceivers 113 and 123 shown in sub-graph (b) of fig. 1 may perform the same functions as the aforementioned transceivers shown in sub-graph (a) of fig. 1. For example, the processing chips 114 and 124 shown in sub-graph (b) of fig. 1 may include processors 111 and 121 and memories 112 and 122. The processors 111 and 121 and memories 112 and 122 shown in sub-graph (b) of fig. 1 may perform the same functions as the aforementioned processors 111 and 121 and memories 112 and 122 shown in sub-graph (a) of fig. 1.

A mobile terminal, a wireless device, a wireless transmit/receive unit (WTRU), a User Equipment (UE), a Mobile Station (MS), a mobile subscriber unit, a user STA, a network, a base station, a node B, an Access Point (AP), a repeater, a router, a repeater, a receive unit, a transmit unit, a receive STA, a transmit STA, a receive device, a transmit device, a receive apparatus, and/or a transmit apparatus described below may mean STAs 110 and 120 shown in sub-graph (a)/(B) of fig. 1, or may mean processing chips 114 and 124 shown in sub-graph (B) of fig. 1. That is, technical features of the present specification may be performed in STAs 110 and 120 shown in sub-graph (a)/(b) of fig. 1, or transceivers 113 and 123 shown in sub-graph (a)/(b) of fig. 1 may be performed only in processing chips 114 and 124 shown in sub-graph (b) of fig. 1. For example, the technical feature of the transmitting STA transmitting the control signal may be understood as the technical feature of transmitting the control signal generated in the processors 111 and 121 illustrated in the sub-diagram (a)/(b) of fig. 1 through the transceiver 113 illustrated in the sub-diagram (a)/(b) of fig. 1. Alternatively, the technical feature of the transmitting STA transmitting the control signal may be understood as the technical feature of generating the control signal to be transmitted to the transceivers 113 and 123 in the processing chips 114 and 124 shown in the sub-graph (b) of fig. 1.

For example, the technical feature of the receiving STA receiving the control signal may be understood as the technical feature of receiving the control signal through the transceivers 113 and 123 shown in the sub-graph (a) of fig. 1. Alternatively, the technical features of the receiving STA to receive the control signal may be understood as the technical features of obtaining the control signal received in the transceivers 113 and 123 shown in the sub-graph (a) of fig. 1 through the processors 111 and 121 shown in the sub-graph (a) of fig. 1. Alternatively, the technical features of the receiving STA to receive the control signal may be understood as the technical features of the receiving STA to obtain the control signals received in the transceivers 113 and 123 shown in the sub-graph (b) of fig. 1 through the processing chips 114 and 124 shown in the sub-graph (b) of fig. 1.

Referring to sub-graph (b) of fig. 1, software codes 115 and 125 may be included in memories 112 and 122. The software codes 115 and 125 may include instructions for controlling the operation of the processors 111 and 121. Software codes 115 and 125 may be included as various programming languages.

The processors 111 and 121 or the processing chips 114 and 124 of fig. 1 may include Application Specific Integrated Circuits (ASICs), other chipsets, logic circuits, and/or data processing devices. The processor may be an Application Processor (AP). For example, processors 111 and 121 or processing chips 114 and 124 of FIG. 1 may include at least one of the following: a Digital Signal Processor (DSP), a Central Processing Unit (CPU), a Graphics Processing Unit (GPU), and a modulator and demodulator (modem). For example, processors 111 and 121 or processing chips 114 and 124 of FIG. 1 may be implemented by SNAPDRAGONTM processor family, manufactured by SEXYNOSTM processor series manufactured by +.>Processor series manufactured by ∈>HELIOTM processor series manufactured by +.>Manufactured ATOMTM processor family or enhancement from such processorsA processor.

In the present specification, the uplink may mean a link for communication from a non-AP STA to an SP STA, and an uplink PPDU/packet/signal or the like may be transmitted through the uplink. In addition, in the present specification, the downlink may mean a link for communication from an AP STA to a non-AP STA, and a downlink PPDU/packet/signal or the like may be transmitted through the downlink.

The upper part of fig. 2 illustrates the structure of an infrastructure Basic Service Set (BSS) of Institute of Electrical and Electronics Engineers (IEEE) 802.11.

Referring to the upper part of fig. 2, the wireless LAN system may include one or more infrastructure BSSs 200 and 205 (hereinafter, referred to as BSSs). BSSs 200 and 205, which are sets of an AP and an STA (e.g., an Access Point (AP) 225 and a station (STA 1) 200-1) that are successfully synchronized to communicate with each other, are not concepts indicating a specific area. BSS 205 may include one or more STAs 205-1 and 205-2 that may join an AP 230.

The BSS may include at least one STA, an AP providing a distributed service, and a Distributed System (DS) 210 connecting the plurality of APs.

The distributed system 210 may implement an Extended Service Set (ESS) 240 extended by connecting the plurality of BSSs 200 and 205. ESS 240 may be used as a term indicating a network configured by connecting one or more APs 225 or 230 via distributed system 210. The APs included in one ESS 240 may have the same Service Set Identification (SSID).

Portal 220 may serve as a bridge connecting a wireless LAN network (IEEE 802.11) and another network (e.g., 802. X).

In the BSS shown in the upper part of fig. 2, a network between the APs 225 and 230 and the ST a 200-1, 205-1, and 205-2 may be implemented. However, the network is configured to perform communication between STAs even without the APs 225 and 230. A network that performs communication by configuring a network between STAs even without the APs 225 and 230 is defined as an ad hoc network or an Independent Basic Service Set (IBSS).

The lower part of fig. 2 illustrates a conceptual diagram illustrating an IBSS.

Referring to the lower part of fig. 2, the IBSS is a BSS operating in an ad hoc mode. Since the IBSS does not include an Access Point (AP), a centralized management entity performing management functions at the center does not exist. That is, in an IBSS, the STAs 250-1, 250-2, 250-3, 255-4, and 255-5 are managed in a distributed manner. In an IBSS, all STAs 250-1, 250-2, 250-3, 255-4, and 255-5 may be comprised of removable STAs and are not allowed to access the DS to form a self-contained network.

Fig. 3 illustrates a general link setup procedure.

In S310, the STA may perform a network discovery operation. The network discovery operation may include a scanning operation of the STA. That is, in order to access the network, the STA needs to discover the participating network. The STA needs to identify a compatible network before joining a wireless network, and the process of identifying networks existing in a specific area is called scanning. The scanning method comprises active scanning and passive scanning.

Fig. 3 illustrates a network discovery operation including an active scanning procedure. In the active scanning, the STA performing the scanning transmits a probe request frame and waits for a response to the probe request frame in order to identify which AP exists around while moving to a channel. The responder transmits a probe response frame to the STA that has transmitted the probe request frame as a response to the probe request frame. Here, the responder may be an STA transmitting the last beacon frame in the BSS of the channel being scanned. In the BSS, the AP is a responder since the AP transmits a beacon frame. In IBSS, the responders are not stationary because STAs in the IBSS send beacon frames in turn. For example, when the STA transmits a probe request frame via channel 1 and receives a probe response frame via channel 1, the STA may store BSS-related information included in the received probe response frame, may move to the next channel (e.g., channel 2), and may perform scanning by the same method (e.g., transmit a probe request and receive a probe response via channel 2).

Although not shown in fig. 3, scanning may be performed by a passive scanning method. In passive scanning, a STA performing scanning may wait for a beacon frame while moving to a channel. The beacon frame is one of management frames in IEEE 802.11, and is periodically transmitted to indicate the presence of a wireless network and enable STAs performing scanning to find and join the wireless network. In a BSS, an AP is configured to periodically transmit a beacon frame. In an IBSS, STAs in the IBSS transmit beacon frames in turn. Upon receiving the beacon frame, the STA performing scanning stores information about BSSs included in the beacon frame and records beacon frame information in respective channels while moving to another channel. The STA that receives the beacon frame may store BSS-related information included in the received beacon frame, may move to the next channel, and may perform scanning in the next channel by the same method.

After discovering the network, the STA may perform an authentication procedure in S320. This authentication process may be referred to as a first authentication process to be clearly distinguished from the security setting operation in S340 that follows. The authentication procedure in S320 may include a procedure in which the STA transmits an authentication request frame to the AP and the AP transmits an authentication response frame to the STA in response. The authentication frame for authentication request/response is a management frame.

The authentication frame may include information about an authentication algorithm number, an authentication transaction sequence number, a status code, challenge text, a Robust Secure Network (RSN), and a limited loop group.

The STA may transmit an authentication request frame to the AP. The AP may determine whether to allow authentication of the STA based on information included in the received authentication request frame. The AP may provide the authentication processing result to the STA via an authentication response frame.

When the STA is successfully authenticated, the STA may perform an association procedure in S330. The association procedure includes a procedure in which the STA transmits an association request frame to the AP and the AP transmits an association response frame to the STA in response. For example, the association request frame may include information about various capabilities, beacon listening intervals, service Set Identifiers (SSID), supported rates, supported channels, RSNs, mobile domains, supported operation categories, traffic Indication Map (TIM) broadcast requests, and interworking service capabilities. For example, the association response frame may include information about various capabilities, status codes, association IDs (AID), supported rates, enhanced Distributed Channel Access (EDCA) parameter sets, received Channel Power Indicator (RCPI), received signal-to-noise indicator (RSNI), mobility domain, time out interval (association recovery time), overlapping BSS scan parameters, TIM broadcast response, and QoS map.

In S340, the STA may perform a security setting procedure. The security setting process in S340 may include a process of setting a private key through a four-way handshake (e.g., through an Extensible Authentication Protocol (EAPOL) frame via a LAN).

Fig. 4 illustrates an example of a PPDU used in the IEEE standard.

As shown, various types of PHY Protocol Data Units (PPDUs) are used in the IEEE a/g/n/ac standard. Ext> specificallyext>,ext> theext> LText> Fext> andext> theext> STFext> includeext> trainingext> signalsext>,ext> theext> SIGext> -ext> aext> andext> theext> SIGext> -ext> bext> includeext> controlext> informationext> forext> aext> receivingext> staext>,ext> andext> theext> dataext> fieldext> includesext> userext> dataext> correspondingext> toext> aext> psduext> (ext> macext> pduext> /ext> aggregateext> macext> pduext>)ext>.ext>

Fig. 4 also includes an example of a HE PPDU according to IEEE 802.11 ax. The HE PPDU according to fig. 4 is an exemplary PPDU for a plurality of users. HE-SIG-B may be included only in PPDUs for multiple users, and HE-SIG-B may be omitted in PP DUs for a single user.

As illustrated in fig. 4, the HE-PPDU for a plurality of users (MUs) may include a legacy short training field (L-STF), a legacy long training field (L-LTF), a legacy signal (L-SIG), a high efficiency signal a (HE-SIG a), a high efficiency signal B (HE-SIG B), a high efficiency short training field (HE-STF), a high efficiency long training field (HE-LTF), a data field (alternatively, a MAC payload), and a Packet Extension (PE) field. The various fields may be transmitted within the time period shown (i.e., 4 or 8 mus).

Hereinafter, a Resource Unit (RU) for PPDU is described. An RU may include a plurality of subcarriers (or tones). The RU may be used to transmit signals to a plurality of STAs according to OFDMA. In addition, an RU may also be defined to transmit a signal to one STA. RU may be used for STF, LTF, data fields, etc.

RU described in this specification can be used for Uplink (UL) communication and Downlink (DL) communication. For example, when performing UL-MU communication solicited by a trigger frame, a transmitting STA (e.g., an AP) may allocate a first RU (e.g., 26/52/106/242-RU, etc.) to the first STA and may allocate a second RU (e.g., 26/52/106/242-RU, etc.) to the second STA through the trigger frame. Thereafter, the first STA may transmit a first trigger-based PPDU based on the first RU, and the second STA may transmit a second trigger-based PPDU based on the second RU. The first/second trigger-based PPDUs are transmitted to the AP in the same (or overlapping) time periods.

For example, when configuring a DL MU PPDU, a transmitting STA (e.g., an AP) may allocate a first RU (e.g., 26/52/106/242-RU, etc.) to the first STA and may allocate a second RU (e.g., 26/52/106/242-RU, etc.) to the second STA. That is, a transmitting STA (e.g., AP) may transmit the HE-STF, HE-LTF, and data field for the first STA through a first RU in one MU PPDU and may transmit the HE-STF, HE-LTF, and data field for the second STA through a second RU.

Fig. 5 illustrates UL-MU based operation. As illustrated, a transmitting STA (e.g., AP) may perform channel access through contention (e.g., backoff operation) and may transmit a trigger frame 1030. That is, the transmitting STA may transmit a PPDU including the trigger frame 1030. Upon receiving a PPDU including a trigger frame, a Trigger (TB) -based PPDU is transmitted after a delay corresponding to a SIFS.

The TB PPDUs 1041 and 1042 may be transmitted within the same period of time and may be transmitted from a plurality of STAs (e.g., user STAs) having an AID indicated in the trigger frame 1030. The ACK frame 1050 for the TB PPDU may be implemented in various forms.

Specific features of the trigger frame are described with reference to fig. 6 to 8. Even if UL-MU communication is used, an Orthogonal Frequency Division Multiple Access (OFDMA) scheme or a MU-MIMO scheme may be used, and both the OFDMA and MU-MIMO schemes may be used.

Fig. 6 illustrates an example of a trigger frame. The trigger frame of fig. 6 allocates resources for uplink multi-user (MU) transmissions and may be transmitted, for example, from an AP. The trigger frame may be composed of a MAC frame and may be included in the PPDU.

Each field shown in fig. 6 may be partially omitted, and another field may be added. In addition, the length of each field may be changed to be different from that shown in the drawings.

The frame control field 1110 of fig. 6 may include information related to a MAC protocol version and additional control information. The duration field 1120 may include time information of NAV configuration or information related to an identifier (e.g., AID) of the STA.

In addition, the RA field 1130 may include address information of the receiving STA of the corresponding trigger frame, and may be optionally omitted. The TA field 1140 may include address information of a STA (e.g., AP) transmitting the corresponding trigger frame. The common information field 1150 includes common control information applied to the receiving STAs receiving the corresponding trigger frame. Ext>ext> forext>ext> exampleext>ext>,ext>ext> aext>ext> fieldext>ext> indicatingext>ext> aext>ext> lengthext>ext> ofext>ext> anext>ext> Lext>ext> -ext>ext> SIGext>ext> fieldext>ext> ofext>ext> anext>ext> uplinkext>ext> PPDUext>ext> transmittedext>ext> inext>ext> responseext>ext> toext>ext> aext>ext> correspondingext>ext> triggerext>ext> frameext>ext> orext>ext> informationext>ext> forext>ext> controllingext>ext> contentsext>ext> ofext>ext> aext>ext> SIGext>ext> -ext>ext> aext>ext> fieldext>ext> (ext>ext> i.e.ext>ext>,ext>ext> heext>ext> -ext>ext> SIGext>ext> -ext>ext> aext>ext> fieldext>ext>)ext>ext> ofext>ext> theext>ext> uplinkext>ext> PPDUext>ext> transmittedext>ext> inext>ext> responseext>ext> toext>ext> theext>ext> correspondingext>ext> triggerext>ext> frameext>ext> mayext>ext> beext>ext> includedext>ext>.ext>ext> In addition, as the common control information, information related to the length of the CP of the uplink PPDU transmitted in response to the corresponding trigger frame or information related to the length of the LTF field may be included.

In addition, it is preferable to include per-user information fields 1160#1 to 1160#n corresponding to the number of receiving STAs receiving the trigger frame of fig. 6. The per-user information field may also be referred to as an "allocation field".

In addition, the trigger frame of fig. 6 may include a padding field 1170 and a frame check sequence field 1180.

Each of the per-user information fields 1160#1 through 1160#n shown in fig. 6 may include a plurality of subfields.

Fig. 7 illustrates an example of a common information field of a trigger frame. The subfields of fig. 7 may be partially omitted and additional subfields may be added. In addition, the length of each of the subfields illustrated may be changed.

The illustrated length field 1210 has the same value as a length field of an L-SIG field of an uplink PPDU transmitted in response to a corresponding trigger frame, and the length field of the L-SIG field of the uplink PPDU indicates the length of the uplink PPDU. As a result, the length field 1210 of the trigger frame may be used to indicate the length of the corresponding uplink PPDU.

In addition, the cascade identifier field 1220 indicates whether a cascade operation is performed. Tandem operation means that within the same TXOP, downlink MU transmissions and uplink MU transmissions are performed together. That is, this means that downlink MU transmission is performed, and thereafter, uplink MU transmission is performed after a preset time (e.g., SIFS). During the tandem operation, only one transmitting device (e.g., an AP) may perform downlink communication, and a plurality of transmitting devices (e.g., non-APs) may perform uplink communication.

The CS request field 1230 indicates whether a wireless medium status or NAV, etc. must be considered in the case where the receiving device, having received the corresponding trigger frame, transmits the corresponding uplink PPDU.

Ext>ext>ext> theext>ext>ext> HEext>ext>ext> -ext>ext>ext> SIGext>ext>ext> -ext>ext>ext> aext>ext>ext> informationext>ext>ext> fieldext>ext>ext> 1240ext>ext>ext> mayext>ext>ext> includeext>ext>ext> informationext>ext>ext> thatext>ext>ext> controlsext>ext>ext> theext>ext>ext> contentext>ext>ext> ofext>ext>ext> aext>ext>ext> SIGext>ext>ext> -ext>ext>ext> aext>ext>ext> fieldext>ext>ext> (ext>ext>ext> i.e.ext>ext>ext>,ext>ext>ext> HEext>ext>ext> -ext>ext>ext> SIGext>ext>ext> -ext>ext>ext> aext>ext>ext> fieldext>ext>ext>)ext>ext>ext> ofext>ext>ext> theext>ext>ext> uplinkext>ext>ext> ppduext>ext>ext> inext>ext>ext> responseext>ext>ext> toext>ext>ext> theext>ext>ext> correspondingext>ext>ext> triggerext>ext>ext> frameext>ext>ext>.ext>ext>ext>

The CP and LTF type field 1250 may include information related to the CP length and LTF length of the uplink PPDU transmitted in response to the corresponding trigger frame. The trigger type field 1260 may indicate the purpose of using the corresponding trigger frame, e.g., a typical trigger, a trigger for beamforming, a request for a block ACK/NACK, etc.

It can be assumed that the trigger type field 1260 of the trigger frame in this specification indicates a base type of trigger frame for a typical trigger. For example, a basic type of trigger frame may be referred to as a basic trigger frame.

Fig. 8 illustrates an example of subfields included in the per-user information field. The user information field 1300 of fig. 8 may be understood as any of the per-user information fields 1160#1 to 1160#n mentioned above with reference to fig. 6. The subfields included in the user information field 1300 of fig. 8 may be partially omitted and additional subfields may be added. In addition, the length of each of the subfields illustrated may be changed.

The user identifier field 1310 of fig. 8 indicates an identifier of a STA (i.e., a receiving STA) corresponding to per-user information. Examples of the identifier may be all or part of an Association Identifier (AID) value of the receiving STA.

In addition, an RU allocation field 1320 may be included. That is, when the receiving STA identified through the user identifier field 1310 transmits a TB PPDU in response to a trigger frame, the TB PPDU is transmitted through the RU indicated by the RU allocation field 1320.

The subfields of fig. 8 may include a coding type field 1330. The coding type field 1330 may indicate a coding type of the TB PPDU. For example, when BCC coding is applied to the TB PPDU, the coding type field 1330 may be set to "1", and when LDPC coding is applied, the coding type field 1330 may be set to "0".

In addition, the subfields of fig. 8 may include an MCS field 1340. The MCS field 1340 may indicate an MCS scheme applied to the TB PPDU. For example, when BCC coding is applied to the TB PPDU, the coding type field 1330 may be set to "1", and when LDPC coding is applied, the coding type field 1330 may be set to "0".

Hereinafter, a UL OFDMA-based random access (UORA) scheme will be described.

Fig. 9 depicts the technical features of the UORA scheme.

A transmitting STA (e.g., AP) may allocate six RU resources by triggering a frame as shown in fig. 9. Specifically, the AP may allocate first RU resources (AID 0, RU 1), second RU resources (AID 0, RU 2), third RU resources (AID 0, RU 3), fourth RU resources (AID 2045, RU 4), fifth RU resources (AID 2045, RU 5), and sixth RU resources (AID 3, RU 6). Information related to AID 0, AID 3, or AID 2045 may be included, for example, in the user identifier field 1310 of fig. 8. Information related to RU 1 through RU 6 may be included, for example, in RU allocation field 1320 of fig. 8. Aid=0 may mean UORA resources for associated STAs and aid=2045 may mean UORA resources for non-associated STAs. Accordingly, the first to third RU resources of fig. 9 may be used as UORA resources for associated STAs, the fourth and fifth RU resources of fig. 9 may be used as UORA resources for non-associated STAs, and the sixth RU resource of fig. 9 may be used as typical resources for UL MUs.

In the example of fig. 9, the OFDMA random access backoff (OBO) of STA1 is reduced to 0, and STA1 randomly selects the second RU resources (AID 0, RU 2). In addition, since the OBO counter of STA2/3 is greater than 0, no uplink resources are allocated to STA2/3. In addition, regarding STA4 in fig. 9, since the AID (e.g., aid=3) of STA4 is included in the trigger frame, the resources of RU 6 are allocated without backoff.

Specifically, since STA1 of fig. 9 is an associated STA, the total number of eligible RA RUs for STA1 is 3 (RU 1, RU 2, and RU 3), and thus STA1 decrements the OBO counter by 3 such that the OBO counter becomes 0. In addition, since STA2 of fig. 9 is an associated STA, the total number of eligible RA RUs for STA2 is 3 (RU 1, RU 2, and RU 3), so STA2 decrements the OBO counter by 3, but the OBO counter is greater than 0. In addition, since STA3 of fig. 9 is a non-associated STA, the total number of eligible RA RUs for STA3 is 2 (RU 4, RU 5), so STA3 decrements the OBO counter by 2, but the OBO counter is greater than 0.

Hereinafter, PPDUs transmitted/received in STAs of the present specification will be described.

Fig. 10 illustrates an example of a PPDU used in the present specification.

The PPDU of fig. 10 may be named in various terms such as EHT PPDU, TX PPDU, RX PPDU, first type or nth type PPDU, etc. For example, in the present specification, a PPDU or an EHT PPDU may be named in various terms such as TX PPDU, RX PPDU, first type or nth type PPDU, etc. In addition, the EHT PPDU may be used in an EHT system and/or a new WLAN system enhanced with respect to the EHT system.

The PPDU of fig. 10 may indicate all or a portion of the type of PPDU used in the EHT system. For example, the example of fig. 10 may be used for both Single User (SU) and multi-user (MU) modes. In other words, the PPDU of fig. 10 may be a PPDU for one receiving STA or a plurality of receiving STAs. When the PPDU of fig. 10 is used in a Trigger (TB) -based mode, the EHT-SIG of fig. 10 may be omitted. In other words, an STA that has received a trigger frame for an uplink MU (UL-MU) may transmit a PPDU in which the EHT-SIG is omitted in the example of fig. 10.

In fig. 10, L-STF to EHT-LTF may be referred to as a preamble or a physical preamble, and may be generated/transmitted/received/obtained/decoded in a physical layer.

The subcarrier spacing of the L-STF, L-LTF, L-SIG, RL-SIG, U-SIG, and EHT-SIG fields of FIG. 10 may be determined to be 312.5kHz and the subcarrier spacing of the EHT-STF, EHT-LTF, and data fields may be determined to be 78.125kHz. That is, the tone indexes (or subcarrier indexes) of the L-STF, L-LTF, L-SIG, RL-SIG, U-SIG, and EHT-SIG fields may be expressed in units of 312.5kHz, and the tone indexes (or subcarrier indexes) of the EHT-STF, EHT-LTF, and data fields may be expressed in units of 78.125kHz.

In the PPDU of fig. 10, L-LTE and L-STF may be the same as those in the conventional field.

The L-SIG field of fig. 10 may include bit information of, for example, 24 bits. For example, the 24-bit information may include a rate field of 4 bits, a reserved bit of 1 bit, a length field of 12 bits, a parity bit of 1 bit, and a tail bit of 6 bits. For example, a 12-bit length field may include information related to the length or duration of the PPDU. For example, a 12-bit length field may be determined based on the type of PPDU. For example, when the PPDU is a non-HT, VHT PPDU or EHT PPDU, the value of the length field may be determined as a multiple of 3. For example, when the PPDU is a HE PPDU, the value of the length field may be determined as "multiple of 3" +1 or "multiple of 3" +2. In other words, for a non-HT, VHT PPDU or EHT PPDU, the value of the length field may be determined as a multiple of 3, and for an HE PPDU, the value of the length field may be determined as a "multiple of 3" +1 or a "multiple of 3" +2.

For example, the transmitting STA may apply BCC coding based on a 1/2 coding rate to 24 bits of information of the L-SIG field. Thereafter, the transmitting STA may obtain 48-bit BCC encoded bits. BPSK modulation may be applied to the 48-bit coded bits, thereby generating 48 BPSK symbols. The transmitting STA may map 48 BPSK symbols to positions other than pilot subcarriers { subcarrier index-21, -7, +7, +21} and DC subcarrier { subcarrier index 0 }. As a result, 48 BPSK symbols may be mapped to subcarrier indexes-26 to-22, -20 to-8, -6 to-1, +1 to +6, +8 to +20, and +22 to +26. The transmitting STA may additionally map signals of { -1, 1} to subcarrier indexes { -28, -27, +27, +28}. The above-mentioned signals may be used for channel estimation in the frequency domain corresponding to { -28, -27, +27, +28}.

The transmitting STA may generate a RL-SIG generated in the same manner as the L-SIG. BPSK modulation may be applied to the RL-SIG. The receiving STA may learn that the RX PPDU is a HE PPDU or an EHT PPDU based on the existence of the RL-SIG.

The common SIG (U-SIG) may be inserted after the RL-SIG of fig. 10. The U-SIB may be named in various terms such as a first SIG field, a first SIG, a first type SIG, a control signal field, a first (type) control signal, etc.

The U-SIG may include N bits of information and may include information for identifying the type of the EHT PPDU. For example, the U-SIG may be configured based on two symbols (e.g., two OFDM symbols in succession). Each symbol of the U-SIG (e.g., an OFDM symbol) may have a duration of 4 μs. Each symbol of the U-SIG may be used to transmit 26 bits of information. For example, each symbol of the U-SIG may be transmitted/received based on 52 data tones and 4 pilot tones.

With the U-SIG (or U-SIG field), for example, a-bit information (e.g., 52 uncoded bits) may be transmitted. The first symbol of the U-SIG may transmit the first X bits of information (e.g., 26 uncoded bits) of the A bits of information, and the second symbol of the U-SIB may transmit the remaining Y bits of information (e.g., 26 uncoded bits) of the A bits of information. For example, the transmitting STA may obtain 26 uncoded bits included in each U-SIG symbol. The transmitting STA may perform convolutional encoding (i.e., BCC encoding) based on a rate of r=1/2 to generate 52 encoded bits, and may perform interleaving on the 52 encoded bits. The transmitting STA may perform BPSK modulation on the interleaved 52 coded bits to generate 52 BPSK symbols to be allocated to each U-SIG symbol. One U-SIG symbol may be transmitted based on 65 tones (subcarriers) from subcarrier index-28 to subcarrier index +28, except for DC index 0. The 52 BPSK symbols generated by the transmitting STA may be transmitted based on the remaining tones (subcarriers) except for pilot tones (i.e., tones-21, -7, +7, +21).

For example, the a-bit information (e.g., 52 uncoded bits) generated by the U-SIG may include a CRC field (e.g., a field of length 4 bits) and a tail field (e.g., a field of length 6 bits). The CRC field and the tail field may be transmitted over a second symbol of the U-SIG. The CRC field may be generated based on 26 bits allocated to the first symbol of the U-SIG and the remaining 16 bits in the second symbol except for the CRC/tail field, and may be generated based on a conventional CRC calculation algorithm. In addition, the tail field may be used to terminate the trellis of the convolutional decoder and may be set to, for example, "000000".

The a-bit information (e.g., 52 uncoded bits) transmitted by the U-SIG (or U-SIG field) may be divided into version-independent bits and version-dependent bits. For example, version independent bits may have a fixed or variable size. For example, version-independent bits may be allocated to only the first symbol of the U-SIG, or version-independent bits may be allocated to both the first symbol and the second symbol of the U-SIG. For example, version-independent bits and version-dependent bits may be named in terms of various terms such as first control bits, second control bits, and the like.

For example, version-independent bits of the U-SIG may include a 3-bit PHY version identifier. For example, the 3-bit PHY version identifier may include information related to the PHY version of the TX/RX PPDU. For example, a first value of a 3-bit PHY version identifier may indicate that the TX/RX PPDU is an EHT PPDU. In other words, when the transmitting STA transmits the EHT PPDU, the 3-bit PHY version identifier may be set to a first value. In other words, the receiving STA may determine that the RX PPDU is an EHT PPDU based on the PHY version identifier having the first value.

For example, version independent bits of the U-SIG may include a 1-bit UL/DL flag field. A first value of the UL/DL flag field of 1 bit is related to UL communication and a second value of the UL/DL flag field is related to DL communication.

For example, version-independent bits of the U-SIG may include information related to TXOP length and information related to BSS color ID.

For example, when the EHT PPDU is divided into various types (e.g., various types such as an EHT PPDU related to SU mode, an EHT PPDU related to MU mode, an EHT PPDU related to TB mode, an EHT PPDU related to extended range transmission, etc.), information related to the type of the EHT PPDU may be included in version-related bits of the U-SIG.

For example, the U-SIG may comprise: 1) A bandwidth field including information related to a bandwidth; 2) A field including information related to an MCS scheme applied to the EHT-SIG; 3) An indication field including information on whether to apply a dual subcarrier modulation (DCM) scheme to the EHT-SIG; 4) A field including information related to a number of symbols for the EHT-SIG; 5) A field including information regarding whether to generate an EHT-SIG across a full frequency band; 6) A field including information related to a type of EHT-LTF/STF; and 7) information related to fields indicating the EHT-LTF length and the CP length.

In the following example, signals expressed as (TX/RX/UL/DL) signals, (TX/RX/UL/DL) frames, (TX/RX/UL/DL) packets, (TX/RX/UL/DL) data units, (TX/RX/UL/DL) data, etc. may be signals transmitted/received based on the PPDU of fig. 10. The PPDU of fig. 10 may be used to transmit/receive various types of frames. For example, the PPDU of fig. 10 may be used for the control frame. Examples of control frames may include Request To Send (RTS), clear To Send (CTS), power save polling (PS poll), blockACKReq, blockAck, null Data Packet (NDP) advertisement, and trigger frames. For example, the PPDU of fig. 10 may be used for management frames. Examples of the management frame may include a beacon frame, (re) association request frame, (re) association response frame, probe request frame, and probe response frame. For example, the PPDU of fig. 10 may be used for a data frame. For example, the PPDU of fig. 10 may be used to simultaneously transmit at least two or more of a control frame, a management frame, and a data frame.

Fig. 11 illustrates an example of a modified transmitting apparatus and/or receiving apparatus of the present specification.

Each device/STA of sub-graph (a)/(b) of fig. 1 may be modified as shown in fig. 11. Transceiver 630 of fig. 11 may be identical to transceivers 113 and 123 of fig. 1. The transceiver 630 of fig. 11 may include a receiver and a transmitter.

Processor 610 of fig. 11 may be identical to processors 111 and 121 of fig. 1. Alternatively, the processor 610 of FIG. 11 may be identical to the processing chips 114 and 124 of FIG. 1.

Memory 620 of fig. 11 may be identical to memories 112 and 122 of fig. 1. Alternatively, memory 620 of FIG. 11 may be a separate external memory from memories 112 and 122 of FIG. 1.

Referring to fig. 11, a power management module 611 manages power for the processor 610 and/or the transceiver 630. The battery 612 supplies power to the power management module 611. The display 613 outputs the result processed by the processor 610. The keyboard 614 receives input to be used by the processor 610. A keyboard 614 may be displayed on the display 613. The SIM card 615 may be an integrated circuit for securely storing an International Mobile Subscriber Identity (IMSI) and its associated keys for identifying and authenticating subscribers on mobile telephone devices such as mobile telephones and computers.

Referring to fig. 11, a speaker 640 may output results related to sound processed by the processor 610. The microphone 641 may receive input related to sound to be used by the processor 610.

Hereinafter, technical features of a multi-link (ML) supported by the STA of the present specification will be described.

STAs (AP and/or non-AP STAs) of the present description may support multi-link (ML) communications. ML communication may mean communication that supports multiple links. Links associated with ML communications may include channels in the 2.4GHz band, the 5GHz band, and the 6GHz band (e.g., 20/40/80/160/240/320MHz channels).

The multiple links for ML communication may be arranged in various ways. For example, the plurality of links for ML communication supported by one STA may be a plurality of channels in the 2.4GHz band, a plurality of channels in the 5GHz band, and a plurality of channels in the 6GHz band. Alternatively, the plurality of links may be a combination of at least one channel within the 2.4GHz band (or the 5GHz/6GHz band) and at least one channel within the 5GHz band (or the 2.4GHz/6GHz band). Further, at least one of the plurality of links for ML communication supported by one STA may be a channel to which preamble puncturing is applied.

The STA may perform ML setup to perform ML communication. The ML setting may be performed based on management frames or control frames such as beacons, probe requests/responses, and association requests/responses. For example, information about ML settings may be included in element fields included in beacons, probe requests/responses, and association requests/responses.

When the ML setup is complete, an enable link for ML communications may be determined. The STA may perform frame exchange over at least one of the plurality of links determined to be enabled links. For example, the enable link may be used for at least one of a management frame, a control frame, and a data frame.

When one STA supports a plurality of links, a transmitting/receiving device supporting each link may operate like one logical STA. For example, one STA supporting two links may be represented as one ML device (multi-link device; MLD) including a first STA for a first link and a second STA for a second link. For example, one AP supporting two links may be represented as one AP MLD including a first AP for a first link and a second AP for a second link. In addition, one non-AP supporting two links may be expressed as one non-AP MLD including a first STA for a first link and a second STA for a second link.

More specific features of the ML setup are described below.

The MLD (AP MLD and/or non-AP MLD) may transmit information on links that the corresponding MLD can support through the ML settings. The link-related information may be configured in various ways. For example, the link-related information includes at least one of 1) information on whether MLD (or STA) supports simultaneous RX/TX operation, 2) information on the number/upper limit of uplink/downlink links supported by MLD (or STA), 3) information on location/frequency band/resource of uplink/downlink links supported by MLD (or STA), 4) types (management, control, data, etc.) of frames available or preferred in at least one uplink/downlink link, 5) ACK policy information available or preferred in respect of at least one uplink/downlink link, 6) information on TID (traffic identifier) available or preferred in respect of at least one uplink/downlink link. The TID is related to the priority of the traffic data and is represented by 8 types of values according to the conventional wireless LAN standard. That is, 8 TID values corresponding to 4 Access Categories (AC) (ac_bk (background), ac_be (best effort), ac_vi (video), ac_vo (voice)) according to the conventional wireless LAN standard may BE defined.

For example, all TIDs for uplink/downlink mapping may be set in advance. In particular, if negotiation is not completed through ML settings, all TIDs may be used for ML communication, and if mapping between uplink/downlink and TIDs is negotiated through additional ML settings, the negotiated TIDs may be used for ML communication.

Multiple links that may be used by a transmitting MLD and a receiving MLD in connection with ML communications may be set by ML settings, and this may be referred to as an enabled link. The enable links may be named differently in various ways. For example, it may be named as various expressions such as a first link, a second link, a transmission link, and a reception link.

After the ML settings are completed, the MLD may update the ML settings. For example, when information about a link needs to be updated, the MLD may send information about a new link. Information about the new link may be transmitted based on at least one of the management frame, the control frame, and the data frame.

The apparatus described below may be the device of fig. 1 and/or 11, and the PPDU may be the PPDU of fig. 10. The device may be an AP or a non-AP STA. The devices described below may be AP multilink devices (MLDs) or non-AP STA MLDs supporting multiple links.

In EHT (extremely high throughput) (standard discussed after 802.11 ax), a multilink environment in which one or more frequency bands are simultaneously used is considered. When the device supports multiple links, the device may use one or more frequency bands (e.g., 2.4GHz, 5GHz, 6GHz, 60GHz, etc.) simultaneously or alternately.

In the following description, MLD means a multi-link device. The MLD has one or more STAs connected and has a MAC Service Access Point (SAP) that communicates with an uplink layer (logical link control, LLC). MLD may mean a physical device or a logical device. Hereinafter, the device may mean MLD.

In the following description, a transmitting apparatus and a receiving apparatus may mean MLD. The first link of the reception/transmission apparatus may be a terminal (e.g., STA or AP) that is included in the reception/transmission apparatus and performs signal transmission/reception through the first link. The second link of the reception/transmission apparatus may be a terminal (e.g., STA or AP) that transmits/receives a signal through the second link included in the reception/transmission apparatus.

In ieee802.11be, two types of multi-link operation may be supported. For example, simultaneous Transmit and Receive (STR) and non-STR operations may be considered. For example, STRs may be referred to as asynchronous multilink operation, and non-STRs may be referred to as synchronous multilink operation. The multilink may comprise multiple frequency bands. That is, the multilink may mean a link included in several frequency bands, or may mean a plurality of links included in one frequency band.

EHT (11 be) considers a multilink technique in which the multilink may include multiple frequency bands. That is, multilinks may represent links of several frequency bands and multiple multilinks within one frequency band at the same time. Two main multilink operations are being considered. It is contemplated that asynchronous operation of TX/RX and impossible synchronous operation are enabled simultaneously over multiple links. Hereinafter, the capability of enabling simultaneous reception and transmission on a plurality of links is referred to as STR (simultaneous transmission and reception), an STA having STR capability is referred to as STR MLD (multi-link device), and an STA not having STR capability is referred to as non-STR MLD.

1. Technical features relating to multiple connection devices

As described above, the multilink system in 802.11be is a system in which a plurality of STAs (AP/non-AP) are co-located in one device (multilink apparatus (MLD)), and can improve the performance of a wireless network.

In addition, a particular TID is mapped to a particular link of the enabled/available links such that traffic for that TID may be sent and received over a designated link (enabled/available link).

Further, as described above, the AP may transmit buffer traffic indication information of a plurality of links through one link or transmit buffer traffic indication information of another link. In this case, only one link among the available (/ enabled) plurality of links operates in the power saving mode, while the other links exist in the doze state, and traffic indications of the other links are displayed through the links operating in the power saving mode. And when receiving, the terminal changes the corresponding link or terminal into an awake state and expects to receive the corresponding service. In this case, the UE may wake up all available links assuming the TID is mapped to all available links. At this time, if the size of data to be actually transmitted from the AP is not large, not all available links are converted to an awake state, but frame transmission/reception is performed through the awake link after only converting a specific link to awake.

2. Embodiments suitable for use in the present description

In existing single link operation, since the traffic indication only gives information on whether or not there is traffic for the corresponding terminal (link), the corresponding terminal (link) is awake and it informs the AP that it has been awake (e.g., PS poll frame or QoS null/data frame transmission) to receive DL frames through the corresponding single link.

However, when a non-AP device (MLD) having a plurality of links has a plurality of links with an associated AP MLD, a specific TID is mapped to the specific link, and a non-AP STA in the non-AP MLD enters a power saving mode. When receiving traffic for the non-AP MLD, the AP MLD may set the corresponding bit of the TIM bitmap to 1 for the STA corresponding to the link of the TID connected to the traffic and transmit it to the non-AP MLD. The non-AP STA/non-AP MLD receives the TIM bitmap and knows on which link the AP has traffic.

If the TID of the non-AP MLD is mapped to all available (enabled/available) links, the AP may set the bit special corresponding to the STA to 1 in the TIM bitmap and transmit it in order to wake up the non-AP STA corresponding to all links. In this case, since the non-AP MLD does not know how much data the AP MLD actually has, all STAs mapped to the available link must be awake, or only specific STAs can be implemented, but this may also be inaccurate. Transitioning all STAs from the doze state to the awake state has the advantage of receiving data quickly, but this may increase the power consumption of the non-AP MLD because the awakened STAs must remain in the doze state for a long time until DL data is received.

Method 0: when the AP receives traffic of TID mapped to all available links in the non-AP MLD, the non-AP MLD notifies all available links (or corresponding STAs) corresponding to the non-AP MLD through the traffic indication bitmap, and the non-AP MLD uses the information to transition the state of the non-AP STA corresponding to each link to the awake state. Fig. 12 shows this example.

Referring to fig. 12, AP1, AP2, and AP3 exist in the AP MLD, and STA1, STA2, and ST A3 in the non-AP MLD are associated with AP1, AP2, and AP3, respectively. Upon receiving traffic corresponding to TIDs mapped to STA1, STA2, and STA3 (i.e., links 1, 2, and 3), the AP indicates that STA1, STA2, and STA3 have buffered traffic. That is, even if there is buffered traffic corresponding to STA1, STA2, and STA3, the AP (or AP MLD) may transmit a traffic indicator to the corresponding STA in order to wake up some of the three STAs. When STA1, STA2, and STA3 of the non-AP MLD transition to the awake state and transmit the UL frame, they inform the AP MLD (or AP) that STA1, STA2, and STA3 are awake. The AP transmits DL frames to two of these ST a (STA 1, STA 2).

Method 1: the AP MLD (or AP) provides a Buffer Status Report (BSR) for the non-AP MLD (or non-AP STA) to the non-AP MLD, or a buffer status report for each STA within the non-AP MLD, or one or more of the buffer status reports for each TID in each STA in the non-AP MLD.

The buffer status report information of the terminal (or non-AP MLD) transmitted by the AP may include one or more of the following information.

1) Buffer traffic volume for non-AP MLD (i.e., queue size for all non-AP MLD)

2) Total amount of buffered traffic (i.e., all queue sizes for each non-AP STA) for each STA in the non-AP MLD: i.e. information about the sum of all queues per STA

3) Buffer traffic for each AC (access class, e.g., ac_vi, ac_vo, ac_be, ac_bk) within each non-AP STA: that is, queue information corresponding to each AC is included for each STA.

4) Buffer traffic for each TID in each non-AP STA: that is, queue information corresponding to each TID is included for each STA.

5) The buffered traffic received from STAs in the non-AP MLD is classified for each AC and the amount of buffered traffic is notified: that is, the queue size information of each AC of the non-AP MLD is included.

6) The buffered traffic received from STAs in the non-AP MLD is differentiated by TID and the buffered traffic is notified: that is, information about the queue size (buffered traffic) of each TID of the non-AP MLD is included.

In this specification we propose an implementation of informing the non-AP MLD of the total amount of buffered traffic, of course, one or more of the above listed information items 1) to 6) may be included in the buffer status information of the non-AP MLD transmitted by the AP.

When the non-AP MLD receives BSR information corresponding to itself (i.e., at least one of the BSR information of the above-described non-AP MLD, BSR information of each STA in the non-AP MLD, queue size information of each AC in each non-AP STA in the non-AP MLD, BSR information of each TID in each non-AP STA in the corresponding non-AP MLD, BSR information of each AC in the corresponding non-AP MLD, and BSR information of each TID in the corresponding non-AP MLD) from the AP MLD, the non-AP MLD may determine how many links (i.e., ST a mapped to links) to wake up based on the corresponding information. The non-AP MLD (or non-AP STAs) may inform the associated AP MLD (or AP) which STAs (or corresponding links) have been awakened. The AP MLD (or AP) may transmit DL frames through the corresponding link based on information transmitted by the UE (information about which non-AP STA among the non-APs has been awakened). Fig. 13 shows this example.

Referring to fig. 13, AP1, AP2, and AP3 exist in the AP MLD, and STA1, STA2, and ST A3 in the non-AP MLD are associated with AP1, AP2, and AP3, respectively. When the AP MLD (or AP 1) transmits a DL frame to STA1 through link 1, an indicator of the presence of buffered traffic is transmitted to STA1 (or non-AP MLD of STA 1) along with the queue size or buffered traffic size (BSR) of the non-AP MLD. When STA1 (or non-AP MLD) receives BSR information from the AP, wakes up STA2 (link 2) and transmits UL frames to the AP (or AP MLD), STA1 transmits information that they are woken up (i.e., information that they are ready to receive DL frames), and the AP (or AP MLD) transmits DL frames to STA1 and STA2 through link 1 and link 2.

Detailed delivery method 1-1: when the AP MLD (or AP STA) transmits the multi-link traffic indication map for the buffer status report information of the non-AP MLD (or non-AP STA) defined above, corresponding frames (e.g., beacon frames) are transmitted together. The non-AP MLD (or non-AP STA) uses the buffer status report information included in the beacon frame to determine how many links (or STAs corresponding to the links) are awake among the plurality of links, and notifies the AP by transmitting a frame including information about the awake links/STAs to the AP. Fig. 14 shows this example.

In fig. 14, it is assumed that TIDs of non-AP MLDs are all mapped to available links by default TID-to-link mapping. In fig. 14, when AP1 transmits a beacon through link 1, AP1 may transmit buffered traffic information of other links/other STAs, and since TID is mapped to all available links, it transmits a TIM that wakes up only the corresponding STA (STA 1 in this example). The non-AP MLD (or STA 1) may also wake up STAs of other links because TID is mapped to all links even though TIM contains information to wake up STA1 only. Fig. 14 shows an example of transition of STA2 to the additional awake state. Based on BSR information about the non-AP MLD included in the received beacon frame, the non-AP MLD may determine how many links to additionally wake up. The non-AP STA1 transmits an UL frame including information for knowing which link STAs have transitioned to the awake state to the AP1, and in fig. 14, STA1 and STA2 notify them that they are in the awake state through the UL frame. Upon receiving the UL frame including information indicating that STA1 and STA2 are in the awake state, the AP MLD transmits immediate acknowledgements of the UL frame to STA1 and STA2 and transmits buffered traffic (e.g., DL frames).

Fig. 15 illustrates an example in which an AP MLD notifies the existence of buffer traffic for a non-AP MLD1 through a beacon frame in a multi-link operation.

In fig. 15, when the AP MLD1 (or AP 1) wakes up the STA through the TIM, information about the non-AP MLD1 is included instead of the STA information. STA1 may know that non-AP MLD1 is the MLD to which STA1 belongs, and non-AP MLD may know that TID is mapped to multiple links (i.e., all available links). As shown in fig. 14, the non-AP MLD may determine how many links to additionally wake up based on BSR information of the non-AP MLD included in the beacon, and in fig. 15, only STA2 is woken up. The rest of the operation is the same as the example of fig. 14.

In fig. 16, when a traffic indication is transmitted in a beacon, an AP MLD (or AP) indicates STAs (STA 1, STA2, and STA 3) mapped to all available links of a TID. Even if the non-AP MLD (or STA) receives this information, it can determine how many links to wake up based on BSR information about the non-AP MLD included in the beacon, and fig. 16 shows an example of additionally waking up STA2 for link 2. The rest of the operation is the same as the example of fig. 14.

2-1. ML-BSR element including BSR information included in beacon frame

The non-AP MLD information of fig. 17 includes information about including the non-AP MLD. That is, the non-AP STA can view which MLD has been indicated by viewing the non-AP MLD information.

Method 1: it may be composed of a field indicating the number of non-AP MLDs and an ID field indicating the non-AP MLDs, and as many non-AP MLD IDs as the number of non-AP MLDs may be included in the information.

Fig. 18 shows an example of ML-BSR elements using method 1.

In detail, the non-AP MLD ID may be an AID of one STA belonging to the non-AP MLD. In this case, if STAs belonging to the MLD have different AIDs, the STAs belonging to the MLD must know the AIDs of other STAs in the same MLD. If STAs belonging to the MLD have the same AID, it is not necessary to separately store the AIDs of other STAs.

If the AIDs of STAs may be the same or different, a method for distinguishing them is additionally required.

Method 2: the non-AP MLD information may be configured in a bitmap form, and each bit is mapped to each non-AP MLD, thus including a queue size field of bit (MLD) set to 1. Further, bitmap size information may be included.

When the same AID is allocated to STAs in the non-AP MLD, the non-AP MLD information bitmap may be configured with bits set to 1 in the TIM bitmap (or ML (multi-link) TIM bitmap), and the queue size information is included as many as the number of bits set to 1 in the non-AP MLD information bitmap. If bitmap size information is included together, the MLD bitmap size is determined as much as the corresponding size, a non-AP MLD (or non-AP STA) indicated by the first bit in the MLD bitmap becomes an MLD (or STA) corresponding to the first bit set to 1 in the TI M bitmap (or ML TIM bitmap), and the subsequent bit becomes an MLD (or STA) corresponding to the second bit set to 1. Fig. 19 shows this example.

Fig. 19 shows an example of ML-BSR elements using method 2.

In fig. 19, the bitmap size may be included as optional. If the bitmap size is included, the size of the ML D bitmap is determined based on the bitmap size value, and as described above, the first bit of the MLD bitmap corresponds to the MLD/STA set to the first 1 of the TIM/ML-TIM bitmap, the second bit corresponds to the ML/STA set to the second 1 of the TIM/ML-TIM bitmap, and the other bits are configured in the same manner. The queue size is included as many as the number of bits set to 1 (i.e., the number of MLD/STAs) in the MLD bitmap. If the bitmap size is not included, the size of the MLD bitmap is set to point to the total number of bits set to 1 in the bitmap of the non-STA/non-AP MLD in the TIM/ML-TIM bitmap. In the above example, since the number of 1 s in the partial virtual bitmap of the TIM element is 5 bits, the size of the MLD bitmap is determined to be 5 bits.

If the AIDs of the STAs in the non-AP MLD always have different values, the STA stores (remembers) the AIDs of other STAs belonging to the same MLD. Therefore, when viewing the MLD bitmap, even if a bit indicating another STA belonging to the same MLD is set to 1, it is considered to point to its own MLD and operate even if the bit does not correspond to itself. As described above, the size of the ML D bitmap is determined by the size indicated by the bitmap size, and as described above, the first bit of the MLD corresponds to the MLD/STA set to the first 1 of the TIM/ML-TIM bitmap, the second is the ML/STA set to the second 1 of the TIM/ML-TIM bitmap, and the other bits are configured in the same manner.

If the AIDs of the STAs may be the same or different, a method for distinguishing them may be additionally required.

Queue size for non-AP MLD: queue size information for each non-AP MLD indicated by the non-AP MLD information is included, and the queue size is repeated as many times as the indicated number of non-AP MLDs. That is, the total size of the queue size is determined as (the size of one queue size is the number of non-AP MLDs).

Scaling factor information indicating unit information of a queue size field may be additionally included, and examples thereof are shown in fig. 20 and 21.

The following table shows an example of scale factor field encoding.

TABLE 1

The scale factor subfield indicates a unit (SF) of the queue size subfield in octets.

The queue size is used to indicate the total size of all MSDUs and a-MSDUs that the AP buffers for the non-AP MLD in combination with the SF value of the scaling factor subfield. When the value of the queue size subfield is a and the scaling factor subfield is 1, it indicates that the total size of all MSDUs and a-MSDUs buffered by the AP for the non-AP MLD is about a×256 octets, and the non-AP MLD (or STA) can also know this. The queue size represents one example and may be expressed differently.

The scaling factor may have a different value for each non-AP MLD, and fig. 22 shows such an example.

As shown in fig. 22, the scaling factor and the queue size are repeated as many times as the number of non-AP MLDs or ST a indicated in the non-AP STA information. For example, if the number of bits set to 1 in the STA bitmap is 5, then 5{ scale factor subfield, queue size subfield }.

< indicator of whether queue size exceeds threshold >

However, as in the above embodiment, if the queue size is directly indicated, the amount of information increases, resulting in an increase in overhead. Hereinafter, an ML-BSR element containing only information on whether a queue size exceeds a certain threshold is proposed.

For example, if 1 bit is configured for each MLD, if the value of the bit is 0, BSR information (i.e., a queue size value) is indicated to exceed a specific threshold, and if the value of the bit is 1, BSR information is indicated to exceed a specific threshold. Fig. 23 shows this example.

In fig. 23, the total number of bits of the queue size is 3 bits, and a first MLD of three STA/MLDs set to 1 in the STA/MLD bitmap indicates that the threshold (=0) is not exceeded, and the second MLD and the third MLD indicate that the threshold (=1) is exceeded.

The above threshold may be determined in the following manner.

1) It is set to a fixed value in the specification/standard. Since this is a fixed value, it has no flexibility.

2) The AP may advertise. The threshold may be included and transmitted when DL frames (particularly, broadcast frames) such as beacons or probe responses are transmitted. For example, the threshold may be transmitted as the queue size information described above. Fig. 24 shows this example.

According to the format of fig. 24, one threshold is equally applied to all MLD/STAs.

Referring to fig. 25, each MLD/STA may have a different threshold, and each MLD may transmit in a queue size.

As an example, the element may be included in a beacon frame or probe response and transmitted as another type of element or field.

3) The AP MLD and the non-AP MLD may negotiate a threshold in advance. Fig. 26 to 28 show this example.

< threshold negotiation method >

Referring to fig. 26, when the non-AP MLD transmits a request frame and the AP MLD transmits a response frame, it includes a threshold value for the AP BSR and transmits the threshold value. Thereafter, when transmitting a beacon frame with an included AP BSR indication, the non-AP MLD may use a value included in the AP BSR indication to know whether the BSR is less than a threshold determined by negotiating or more BSRs.

As for request and response frames, the association request/response frame may be one example, and fig. 27 shows an example thereof.

The non-AP MLD may be transmitted by including a recommendation threshold in the request frame. Fig. 28 shows this example.

Referring to fig. 28, association requests and association responses are examples of request and response frames, and the threshold may be negotiated through other request/response frames.

non-AP STA information: indicating which non-AP STAs are included. That is, the non-AP STA can see the non-AP STA information to know which non-AP STA is indicated and which queue size is included.

Method 1: it may be composed of a field indicating the number of non-AP STAs and an ID field indicating the non-AP STAs, and the non-AP STA IDs are included as many as the number of non-a PSTAs. Fig. 30 shows this example.

Fig. 30 shows another example of an ML-BSR element.

Referring to fig. 30, when different AIDs are always allocated to STAs in a non-AP MLD (e.g., a unique AID is allocated to STAs in an MLD in one AID space), a non-AP STA ID is included as many as the number of non-AP STAs that should include a queue size.

If STAs within a non-AP MLD are assigned the same AID, a method for distinguishing them is required. The non-AP STA ID information includes a non-AP STA ID and link information (e.g., link ID) to distinguish STAs in the MLD.

Method 2: the non-AP STA information may be configured as a bitmap, and since each bit is mapped to each non-AP STA, a queue size of a bit (i.e., STA) set to 1 is included. Further, bitmap size information may be included.

If the AIDs of the STAs in the non-AP MLD always have different values and the TIM element may indicate all the STAs in the non-AP MLD, the terminal set to 1 in the TIM bitmap is configured as a non-AP STA information terminal. If bitmap size information is present, the non-AP STA bitmap size is determined as many as the size indicated in the size field, and if bitmap size information is not present, it is determined that the non-AP STA is as many bits set to 1 in the TIM bitmap (or ML-TIM bitmap). Thus, the first bit of the STA bitmap corresponds to the first MLD/STA set to 1 in the TIM/ML-TIM bitmap, the second bit corresponds to the ML/STA set to 1 in the second TIM/ML-TIM bitmap, and the remaining bits are also configured in the same manner. Fig. 31 shows this example.

Fig. 31 shows another example of an ML-BSR element.

In fig. 31, the bitmap size may be included as optional. If the bitmap size is included, the size of the MLD bitmap is determined based on the bitmap size value, and as described above, the first bit of the STA bitmap corresponds to the MLD/STA set to the first 1 of the TIM/ML-TIM bitmap, the second bit corresponds to the ML/STA set to the second 1 of the TIM/ML-TIM bitmap, and the other bits are configured in the same manner. The queue size is included as many as the number of bits set to 1 (i.e., the number of MLD/STAs) in the MLD bitmap.

Queue size for non-AP STAs: the queue size information for each non-AP STA indicated by the non-AP STA information is included, and the queue size is repeated as many times as the indicated number of non-AP STAs. That is, the total size of the queue size is determined as (the size of one queue size is the number of non-AP STAs).

Method 2: when the AP receives traffic with a TID of a default TID-to-link mapping (i.e., TID is mapped to all available links), the AP responds to one or more of all available links. The traffic indication information is transmitted only to the STA. The non-AP MLD wakes up the corresponding terminal based on the information indicated by the traffic indication information, and transmits a frame including information about the wake-up STA to the AP MLD/AP to inform which terminal is woken up. Fig. 32 shows this example.

Referring to fig. 32, AP1, AP2, and AP3 exist in the AP MLD, and STA1, STA2, and ST A3 in the non-AP MLD are associated with AP1, AP2, and AP3, respectively. Upon receiving traffic corresponding to TIDs mapped to STA1, STA2, and STA3 (i.e., link 1, link 2, and link 3), the AP may indicate that only STA1 and STA2 of STA1, STA2, and STA3 have buffered traffic. That is, even if there is buffered traffic corresponding to STA1, STA2, and STA3, the AP (or AP MLD) may transmit a traffic indication to the corresponding STAs so as to wake up some of the three STAs.

In fig. 32, when the AP MLD (or AP 1) transmits a DL frame to the STA1 through the link 1 and an indicator indicating that the STA1 (or the non-AP MLD of the ST A1) has a buffer service, the AP MLD transmits information to the awake STA2 (i.e., the STA2 also has a buffer service). If the non-AP MLD wakes up STA1 and STA2 (link 2) based on the information received from the AP and transmits UL frames to the AP (or AP MLD), and if STA1 and STA2 transmit the information that they are waken up (i.e., the information that they are ready to receive DL frames), the AP (or AP MLD) transmits DL frames to STA1 and STA2 through link 1 and link 2.

< how to transmit by including additional information such as delay traffic in addition to the AP BSR >

As described above, when an AP transmits a beacon including a TIM, the AP may also transmit buffered traffic for non-AP MLD (e.g., the queue size of non-AP MLD). At this time, the AP may also transmit an attribute of the buffered traffic, and may transmit one or more of the following listed items together with the buffered traffic included in the attribute.

1) Lower latency traffic/data indication: this is an indicator indicating whether lower delay traffic is included in the buffered traffic. For example, if the value is set to 1, the indicator indicates that there is lower latency traffic. The indicator consists of one bit but may include TID for lower latency traffic instead of the indicator. If more than one TID can be included, if there are multiple services and a TID for one service is to be included, the TID for the highest priority (or emergency) service is included in the indicator.

2) Time sensitive traffic/data indication: this is an indicator indicating whether time sensitive traffic is included in the buffered traffic. For example, if the value is set to 1, the indicator indicates that there is time sensitive traffic. It may be included with the lower latency traffic/data indicator or one of the two. The indicator consists of one bit but may include TID for time sensitive traffic instead of the indicator. If more than one TID can be included, the indicator includes the TID of the highest priority (or emergency) service when there are multiple services and the TID for one service is to be included.

3) Service ID (TID): the service ID of the buffered service includes the following.

A. Option 1: including representative service IDs

B. Option 2: including all traffic IDs. The corresponding TID may be included continuously or a TID bitmap may be included. In the case of a TID bitmap, each bit in the bitmap corresponds to each TID.

C. Option 3: including one or more TIDs corresponding to lower latency traffic (or time sensitive traffic).

The non-AP MLD that has obtained the corresponding information (one or more of lower latency traffic/data indication, time sensitive traffic/data indication, traffic ID (TID)) determines how many non-AP STAs within the MLD to wake up and wake up based on the corresponding information.

The corresponding information (one or more of low latency traffic/data indication, time sensitive traffic/data indication, traffic ID (TID)) may be transmitted with the buffered traffic of the non-AP MLD defined above (e.g., BSR for the non-AP MLD) or may be transmitted independently.

The corresponding information (one or more of low latency traffic/data indication, time sensitive traffic/data indication, traffic ID (TID)) may be included in the form of an element in the beacon frame and transmitted, or may be included in the form of an a control field in the DL frame and transmitted.

Referring to fig. 33, since the delay flag is set to 1, it indicates that the AP MLD has lower delay traffic. Accordingly, the non-AP MLD wakes up STA1 and STA2 to quickly receive data, and the non-AP MLD transmits an UL frame to the AP MLD to inform that ST A1 and STA2 have occurred. In fig. 33, STA1 notifies STA1 and STA2 of the awake state by one UL frame, but STA1 and STA2 may transmit UL frames (PS poll, qoS null frames) by each link, respectively, to notify them of the awake state.

Fig. 34 shows an example of transmitting by including a lower delay traffic indicator in a DL frame transmitted to a corresponding non-AP MLD instead of a beacon.

In fig. 34, TIM information for waking up the non-AP MLD is included in the beacon. After STA1 wakes up, it informs the AP that STA1 has waken up by sending UL frames such as PS-poll or QoS null frames over link 1. When the AP receives PS-poll or QoS null from the terminal, thereafter, when a DL frame is transmitted to the corresponding terminal, information indicating that there is lower delay traffic (delay flag=1) is included in the DL frame and transmitted together with the BSR for the non-AP MLD. Upon receiving the BSR and the delay flag, the non-AP MLD wakes up STA2, and STA2 transmits an UL frame to the AP to inform STA2 of the wake-up.

2-2. BSR information of non-AP MLD included in DL frame

Fig. 35 illustrates an example in which an AP MLD notifies BSR information of a non-AP MLD through a DL frame in a multi-link operation.

Detailed delivery mode: when the AP MLD (or AP STA) transmits a separately addressed (i.e., unicast) frame to the awake UE, BSR information of the non-AP MLD (or non-AP STA) defined above is included in a corresponding frame (e.g., DL data frame) and transmitted. The non-AP MLD (or non-AP STA) uses the buffer status report information included in the DL frame to determine how many links (or STAs corresponding to the links) among the plurality of available links are to be transitioned to awake, and it informs the AP by transmitting an uplink frame including information about the awake links/STAs to the AP.

In fig. 35, it is assumed that TIDs of non-AP MLDs are all mapped to available links by default TID-to-link mapping. In fig. 35, when AP1 transmits a beacon through link 1, it may transmit buffered traffic information for another link/another STA, and because TID is mapped to all available links, a beacon frame including a wakeup TIM is transmitted only to the corresponding STA (e.g., STA 1). Even though the TIM contains information to wake STA1 only, the non-AP MLD (or STA 1) transitions STA1 to the awake state even though the TID is mapped to all links. Thereafter, STA1 may transmit an UL frame (i.e., PS poll or QoS null) informing that it has occurred to the AP, and may receive an Ack frame in response thereto. When the AP1 transmits a DL frame to the STA1, buffer status information (e.g., BSR or queue size) of the non-AP MLD corresponding to the ST A1 is included and transmitted. When STA1 receives the DL frame and receives BSR information about the non-AP MLD, it can determine how many available links are awake. (in the embodiment of the present specification, only BSR information for non-AP MLD is described, but as described above, a method for including one or more of various types of BSR (e.g., BSR information for each STA in the non-AP MLD, or BSR information for each AC (or TID) of the non-AP MLD, etc.) may be substituted). Fig. 35 shows an example of transition of STA2 for link 2 from the doze state to the awake state. STA1 shows an example of sending an ACK/BA as a response to AP1 after receiving the DL frame. Subsequent operations of the non-AP MLD (STA) and the AP (/ AP MLD) may perform one or more of the following operations.

1) As shown in fig. 35, an AP1 (or AP MLD) receiving a response frame (ACK/BA) for DL frame transmission including a BSR for non-AP MLD may also transmit DL frames through other links (link 2). However, this has a problem that the STA2 cannot be guaranteed to be awake.

2) When the non-AP STA (STA 1) receives a BSR for a non-AP MLD from the AP, it determines that the link is awake (or STA is mapped to the link) based on the BSR information, and the information of the awake STA is included and transmitted at the time of transmitting the UL frame. The AP may transmit DL frames through a plurality of links based on wake-up information of UEs included in the UL frame. Fig. 36 shows this example.

In fig. 36, STA1 determines to additionally transition STA2 (link 2) to the awake state based on BSR information about the non-AP MLD included in the first DL frame. After STA2 is awake, when STA1 transmits an UL frame to inform STA2 of being awake, information about this is included and transmitted. Thereafter, the AP MLD shows an example of transmitting DL frames to the non-AP MLD using link 1 and link 2.

Instead of STA1 informing the AP MLD (or AP 1) "STA2 has transitioned to the awake state", STA2 may inform it that has transitioned to the awake state through link 2. Fig. 37 shows this example.

In fig. 37, STA1 (or non-AP MLD) determines to additionally transition STA2 (link 2) to the awake state based on BSR information about the non-AP MLD included in the first DL frame. After STA2 wakes up, STA2 transmits an UL frame over link 2 to inform STA2 that it has been woken up. Upon receiving a UL frame (e.g., PS poll/QoS null frame) from STA2 over link 2, AP MLD knows that STA2 has woken up and sends DL frames to non-AP MLD using link 1 and link 2.

< BSR information how to configure non-AP MLD >

BSR information of the non-AP MLD included in the DL frame may be configured in the following manner.

Fig. 38 shows an example of an HT control field.

BSR information of the non-AP MLD is included in the HT control field and transmitted.

When both B0 and B1 of the HT control field are set to 1, HE variable of the HT control field is changed, and the remaining bits consist of the a control subfield. Fig. 38 shows this example.

Fig. 39 shows an example of an a control subfield.

The a control subfield has a length of 30 bits and the control list subfield includes one or more control subfields.

Fig. 40 shows an example of a control subfield format.

The control ID subfield indicates the type of information transmitted in the control information subfield, and the length of the control information subfield is fixed for each value of the control ID subfield. Other control information is configured according to the value of the control ID.

As described above, BSR information of the non-AP MLD may be defined as a new control subfield.

Fig. 41 shows an example of a non-AP BSR (NMB) control subfield.

The control ID of fig. 41 indicates a non-AP MLD BSR (NMB), and the queue size of fig. 41 indicates total queue size information of the non-AP MLD to which the corresponding STA (STA indicated by the receiver address) belongs.

The queue size information may also use a scaling factor as shown in fig. 42 to extend the queue size.

The queue size is used to indicate the total size of all MSDUs and a-MSDUs buffered by the AP for non-AP MLDs in combination with the SF value of the scaling factor subfield. When the value of the queue size subfield is a and the scaling factor subfield is 1, it indicates that the total size of all MSDUs and a-MSDUs buffered by the AP for the non-AP MLD is about a×256 octets, and the non-AP MLD (or STA) can also know this.

The AP-MLD (or AP) may include and transmit one or more of the information listed below, including all the buffer information indicating the non-AP MLD.

ACI (access class indication) information (e.g., 4-bit size): information indicating which BSR information corresponds to which AC (access category, e.g., ac_vo, ac_vi, ac_be, ac_bk). When included in the form of a bitmap, each bit is mapped to each AC, indicating that there is traffic for the AC set to 1. The following table shows an example of ACI bitmap subfield coding.

TABLE 2

B0	B1	B2	B3
				AC_BE	AC_BK	AC_VI	AC_VO

Δ TID (Delta TID) (e.g., 2-bit size): the number of TIDs indicating ACI bitmap subfields and report buffer status, and the following table shows an example of Δtid subfield coding.

TABLE 3

ACI high subfield (e.g., 2-bit size): used with the queue size high subfield, the ACI for the AC of the BSR indicated in the queue size high subfield is indicated, and the table above shows an example of ACI to AC coding.

Queue size high subfield (e.g., 8-bit size): the SF element of the scaling factor subfield is used to indicate the buffered traffic of the AC indicated in the ACI high subfield.

Queue size all subfields: the buffer traffic of all ACs indicated by the ACI bitmap subfield is represented using SF octet units of the scaling factor subfield.

In addition, in the queue size high and all subfields of the queue size, a value 254 indicates that the buffered traffic is greater than 254×sf octets, and a value 255 indicates that the buffered traffic is unspecified or unknown.

As described above, the values indicated by the scaling factors are applied to the queue size heights and queue size all, the ACI bitmap and Δtid values are applied to the queue size all, and the ACI heights are applied to the queue size heights.

In the above, as an example, the AP (or AP MLD) defines and uses a new control subfield to inform the BSR of a specific non-AP MLD. Hereinafter, a method of using the existing BSR control subfield will be described.

Fig. 44 shows the format of the BSR control subfield in the 802.11ax system.

The BSR control subfield of fig. 44 is an HT control field used when the UE transmits its own buffer status to the AP. In this specification, for simplicity of definition, an existing BSR control subfield is used when an AP MLD transmits buffer traffic of a specific non-AP MLD among its BSRs to a corresponding non-AP STA. However, to use this, the BSR transmitted by the AP is not the buffer status of a particular non-AP STA, but a corresponding non-AP STA (i.e., STA indicated by the receiver address of the frame including the BSR control field). It needs to be redefined to indicate the traffic to be sent to the non-AP ML D to which the non-AP STA belongs, and in this case, there must be a limit in which BSR information for a specific non-AP STA cannot be delivered.

That is, when the AP transmits the BSR control field, the information included in the BSR control field indicates BSR information of the MLD to which the STA belongs, indicated by the receiver address of the frame including the BSR control field.

If the address is set to a broadcast address, the AP displays AC information about its entire buffered traffic and queue size information for high AC and information about the number of TIDs.

The information defined above may be defined and transmitted in different forms as follows.

1) Buffer traffic for each AC (access class, e.g., ac_vi, ac_vo, ac_be, ac_bk) within each non-AP STA: that is, each STA contains queue information corresponding to each AC

2) Buffer traffic per TID in each non-AP STA: that is, queue information corresponding to each TID is included for each STA

3) Buffered traffic received from STAs in the non-AP MLD is classified by the AC and the buffered traffic is notified: that is, the queue size information of each AC of the non-AP MLD is included.

4) The buffered traffic received from STAs in the non-AP MLD is differentiated by TID and the amount of buffered traffic is notified: that is, information about the queue size (buffered traffic) of each TID of the non-AP MLD is included.

It goes without saying that the format defined above may be transmitted in other forms.

For example, by including TID information in addition to the above information, TID traffic of which MLD the corresponding BSR information is may be indicated.

Further, the non-AP MLD may be notified of queue size information of a specific TID of a specific non-AP MLD by using a QoS control field instead of an a control field. At this time, if the TID has a specific value in the QoS control field, it indicates that the entire queue size of the corresponding MLD is notified.

< how to send buffer status for non-AP MLD through AP PS buffer status of QoS control field >)

As another detailed method, the AP MLD (or AP) may inform the buffer status for the non-AP MLD by using the AP PS buffer status defined in the QoS control field. The following table shows the AP PS buffer status in the QoS control field.

TABLE 4

The AP PS buffer status subfield is defined as follows.

Fig. 45 shows an example of an AP PS buffer status subfield.

Referring to fig. 45, the AP PS buffer status subfield is an 8-bit field indicating the status of the PS buffer buffered for the STA in the AP. The AP PS buffer status subfield is divided into three subfields: the buffer status indication subfield, the highest priority buffer AC subfield and the AP buffer load subfield.

The buffer status indication subfield has a length of 1 bit and is used to indicate the AC of the highest priority traffic buffered in the remaining APs except the MSDU or a-MSD U in the current frame.

The AP buffer load subfield has a length of 4 bits and is used to indicate the total buffer size (rounded to the nearest multiple of 4096 octets and expressed in units of 4096 octets) of all MSDUs or a-MSDUs buffered in the QoS AP (except for the MSDUs or a-MSDUs of the current QoS data frame). The AP buffer load subfield with a value of 15 indicates a buffer size of greater than 57344 octets. When the buffer status indication bit is 1, the AP buffer load subfield having a value of 0 is used alone to indicate that there is no buffered traffic for the highest priority buffered AC.

If the buffer status indicator bit is 0, the highest priority buffer AC subfield and the AP buffer load subfield are reserved.

Referring to fig. 46, it can be seen that the reserved field of the AP PS buffer status subfield can be used to indicate the buffer status of the non-AP MLD.

The non-AP MLD PS buffer status indication subfield is a field indicating whether information on buffer traffic (i.e., what the AP is storing) of the non-AP MLD of the receiver (non-AP STA) of the QoS frame including the QoS control field is included in the AP PS buffer status field. When the non-AP MLD PS buffer status indication subfield is set to 1, the highest priority buffer AC indicates the highest priority AC of the buffered traffic of the non-AP MLD to which the non-AP STA belongs, which is a receiver of QoS frames including the QoS control field, and the QoS AP buffer load also indicates the total buffer size of the corresponding non-AP MLD. That is, through the AP PS buffer status subfield of fig. 46, buffer traffic (all MSDUs and a-MSDUs of the non-AP MLD buffered at the QoSAP MLD) can be delivered.

The non-AP MLD PS buffer status is used to indicate whether the APPS buffer status is for a non-AP MLD of a receiver (i.e., a non-AP STA) of QoS frames including a QoS control field.

The buffer status indication subfield is used to indicate whether the AP PS buffer status is specified. The buffer status indication subfield is set to 1 to indicate that the AP PS buffer status is specified.

If the indicated non-AP MLD PS buffer status is set to 1, the AC subfield of the highest priority buffer is used to indicate AC for the highest priority traffic among the traffic for the corresponding non-AP MLD, except for the MSDU or a-MSDU of the current frame among the traffic buffered in the AP MLD.

Among all MSDUs and a-MSDUs buffered in the QoS AP, the AP buffer load subfield is rounded up to the nearest multiple of 4096 octets for all MSDUs and a-MSDUs of the non-AP MLD and is used to indicate the total buffer size in units of 4096 octets.

The AP buffer load subfield set to 15 indicates that the buffer size is greater than 57344 octets. The AP buffer load subfield set to 0 is only used to indicate that the highest priority buffered AC indicated when the buffer status indication bit is 1 does not buffer traffic.

When the buffer status indication subfield is 0, the highest priority buffer AC subfield and the AP buffer load subfield are reserved.

Hereinafter, the above-described embodiment will be described with reference to fig. 1 to 46.

Fig. 47 is a flowchart showing a procedure for transmitting BSR information in a multilink operation according to the present embodiment.

The example of fig. 47 may be performed in a network environment supporting a next generation WLAN system (IEEE 802.11be or EH TWLAN system). The next generation wireless LAN system is a WLAN system enhanced from the 802.11ax system, and thus can satisfy backward compatibility with the 802.11ax system.

The example of fig. 47 may be performed in transmitting MLD.

In step S4710, a transmitting multi-link device (MLD) transmits a Downlink (DL) frame to a receiving MLD.

In step S4720, the transmitting MLD receives UL frames from the receiving MLD.

In particular, the buffer status subfield may include a reserved field and first to third subfields.

The reserved field may include information on whether the buffer status subfield includes BSR information for the receiving MLD. The first subfield may include information on whether an access point power save (AP PS) buffer status is specified.

When the reserved field is set to 1, BSR information for the receiving MLD may be included in the buffer status subfield. The second subfield may include information about an Access Category (AC) of traffic buffered in the transmitting MLD having the highest priority for the receiving MLD. The third subfield may include information about the total buffer size for traffic of the receiving MLD buffered in the transmitting MLD.

The total buffer size for traffic receiving MLD may be rounded up to the nearest multiple of 4096 octets and set in units of 4096 octets. When the third subfield is set to 15, it can be determined that the total buffer size for traffic receiving the MLD is greater than 57344 octets. When the first subfield is set to 1 and the third subfield is set to 0, the third subfield may include information that no traffic is buffered for the AC of the highest priority traffic.

When the first subfield is set to 0, it may be determined that the AP PS buffer status is not specified, and the second subfield and the third subfield may be reserved.

As another example, the present specification proposes a method for including and transmitting additional information such as low delay traffic in addition to BSR information for a reception MLD.

The DL frame may further include a first information field, a second information field, or a third information field. The first information field may include information on whether low-delay traffic is included in traffic for the receiving MLD buffered in the transmitting MLD. The second information field may include information on whether time-sensitive traffic is included in traffic buffered in the transmitting MLD for the receiving MLD. The third information field may include information about a service Identifier (ID) of the service buffered in the transmitting MLD for the receiving MLD. For example, when the first information field is set to 1, low-delay traffic may be included in traffic for a receiving MLD buffered in a transmitting MLD. When the second information field is set to 1, time sensitive traffic may be included in traffic buffered in the transmitting MLD for the receiving MLD.

At least one STA included in the receiving MLD transitions to an awake state based on the first information field, the second information field, or the third information field. Further, the UL frame may include information indicating that at least one STA is in an awake state. The UL frame may be a PS poll frame or a QoS null frame. For example, assume that a transmitting MLD includes a first AP and a second AP, a receiving MLD includes a first STA and a second STA, the first AP and the first STA operate on a first link, and the second AP and the second STA operate on a second link. Both the first STA and the second STA may transition to the awake state based on the first information field. In this case, the first STA may inform the first STA and the second STA that they are in the awake state through the UL frame on the first link. Alternatively, the first STA may notify it to be in the awake state through an UL frame on the first link, and the second STA may notify it to be in the awake state through an UL frame on the second link.

As another example, when the DL frame is a beacon frame, BSR information about the receiving MLD may include threshold and queue size subfields. The queue size subfield may include information on whether the queue size of each receiving MLD (or each receiving STA) exceeds a threshold.

The threshold value may be obtained through pre-negotiation without being included in BSR information for the receiving MLD. For example, the transmitting MLD and the receiving MLD may negotiate a threshold for BSR of the receiving MLD through (association) request/response frames. Based on the negotiated threshold, the queue size subfield may include information on whether the queue size of each receiving MLD (or each receiving STA) exceeds the threshold. Accordingly, when buffer status information for a receiving MLD is notified, the transmitting MLD may not notify the queue size itself, thereby reducing overhead.

The example of fig. 48 may be performed in a network environment supporting a next generation WLAN system (IEEE 802.11be or EHT WLAN system). The next generation wireless LAN system is a WLAN system enhanced from the 802.11ax system, and thus can satisfy backward compatibility with the 802.11ax system.

The example of fig. 48 may be performed in a receiving MLD.

In step S4810, a receiving multi-link device (MLD) receives a Downlink (DL) frame from a transmitting MLD.

In step S4820, the receiving MLD transmits a UL frame to the transmitting MLD.

The total buffer size for traffic receiving MLD may be rounded up to the nearest multiple of 4096 octets and set in units of 4096 octets. When the third subfield is set to 15, it can be determined that the total buffer size for traffic receiving the MLD is greater than 57344 octets. When the first subfield is set to 1 and the third subfield is set to 0, the third subfield may include information about the AC for the highest priority traffic having no buffered traffic.

The DL frame may further include a first information field, a second information field, or a third information field. The first information field may include information on whether low-delay traffic is included in traffic for the receiving MLD buffered in the transmitting MLD. The second information field may include information on whether time-sensitive traffic is included in traffic buffered in the transmitting MLD for the receiving MLD. The third information field may include information about a service Identifier (ID) of the service buffered in the transmitting MLD for the receiving MLD. For example, when the first information field is set to 1, low-delay traffic may be included in traffic for a receiving MLD buffered in a transmitting MLD. When the second information field is set to 1, time-sensitive traffic may be included in traffic for the receiving MLD buffered in the transmitting MLD.

At least one STA included in the receiving MLD transitions to an awake state based on the first information field, the second information field, or the third information field. In addition, the UL frame may include information indicating that at least one STA is in an awake state. The UL frame may be a PS poll frame or a QoS null frame. For example, assume that a transmitting MLD includes a first AP and a second AP, a receiving MLD includes a first STA and a second STA, the first AP and the first STA operating on a first link, and the second AP and the second STA operating on a second link. Both the first STA and the second STA may transition to the awake state based on the first information field. In this case, the first STA may inform the first STA and the second STA that they are in the awake state through the UL frame on the first link. Alternatively, the first STA may notify it to be in the awake state through an UL frame on the first link, and the second STA may notify it to be in the awake state through an UL frame on the second link.

The threshold value may be obtained through pre-negotiation without being included in BSR information for the receiving MLD. For example, the transmitting MLD and the receiving MLD may negotiate a threshold for BSR of the receiving MLD through (association) request/response frames. Based on the negotiated threshold, the queue size subfield may include information on whether the queue size for each receiving MLD (or each receiving STA) exceeds the threshold. Accordingly, when buffer status information for a receiving MLD is notified, the transmitting MLD may not notify the queue size itself, thereby reducing overhead.

3. Device configuration

The technical features of the present disclosure may be applied to various apparatuses and methods. For example, the technical features of the present disclosure may be performed/supported by the apparatus of fig. 1 and/or 11. For example, the technical features of the present disclosure may be applied only to a portion of fig. 1 and/or 11. For example, the technical features of the present disclosure may be implemented based on the processing chips 114 and 124 of fig. 1, or based on the processors 111 and 121 and the memories 112 and 122, or based on the processor 610 and the memory 620 of fig. 11. For example, an apparatus according to the present disclosure receives a Downlink (DL) frame from a transmitting multi-link apparatus (MLD); and transmits UL frames to the transmitting MLD.

The technical features of the present disclosure may be implemented based on a Computer Readable Medium (CRM). For example, CRM in accordance with the present disclosure is at least one computer-readable medium comprising instructions designed to be executed by at least one processor.

The CRM may store instructions to perform operations comprising: receiving a Downlink (DL) frame from a transmitting multi-link device (MLD); and transmitting an UL frame to the transmitting MLD. The at least one processor may execute instructions stored in a CRM according to the present disclosure. The at least one processor associated with CRM of the present disclosure may be the processors 111, 121 of fig. 1, the processing chips 114, 124 of fig. 1, or the processor 610 of fig. 11. Meanwhile, CRM of the present disclosure may be the memories 112, 122 of fig. 1, the memory 620 of fig. 11, or a separate external memory/storage medium/disk.

The foregoing features of the present specification are applicable to various applications or business models. For example, the foregoing features may be applied to wireless communications of an Artificial Intelligence (AI) -enabled device.

Artificial intelligence refers to a research field about artificial intelligence or a method for creating artificial intelligence, and machine learning refers to a research field about a method for defining and solving various problems in the artificial intelligence field. Machine learning is also defined as an algorithm that improves operational performance through a steady operational experience.

An Artificial Neural Network (ANN) is a model used in machine learning, and may refer to a model that solves a problem as a whole, including artificial neurons (nodes) that form a network by combining synapses. The artificial neural network may be defined by a connection pattern between neurons of different layers, a learning process to update model parameters, and an activation function to generate output values.

The artificial neural network may include an input layer, an output layer, and optionally one or more hidden layers. Each layer includes one or more neurons, and the artificial neural network may include synapses connecting the neurons. In an artificial neural network, each neuron may output a function value of an activation function of an input signal input through synapses, weights, and deviations.

Model parameters refer to parameters determined by learning and include weights of synaptic connections and deviations of neurons. Super-parameters refer to parameters to be set before learning in a machine learning algorithm and include learning rate, number of iterations, minimum batch size, and initialization function.

Learning the artificial neural network may be aimed at determining model parameters for minimizing the loss function. The loss function may be used as an index to determine optimal model parameters in learning the artificial neural network.

Machine learning can be classified into supervised learning, unsupervised learning, and reinforcement learning.

Supervised learning refers to a method of training an artificial neural network with labels given to training data, where when the training data is input to the artificial neural network, the labels may indicate correct answers (or result values) that the artificial neural network needs to infer. Unsupervised learning may refer to a method of training an artificial neural network without a tag given to training data. Reinforcement learning may refer to a training method for training agents defined in an environment to select actions or sequences of actions to maximize the jackpot per state.

Machine learning, which is implemented using a Deep Neural Network (DNN) including a plurality of hidden layers, among artificial neural networks is called deep learning, and deep learning is a part of machine learning. Hereinafter, machine learning is interpreted to include deep learning.

The foregoing technical features may be applied to wireless communication of a robot.

Robots may refer to machines that utilize their own capabilities to automatically process or operate a given task. In particular, a robot having a function of recognizing an environment and autonomously making a judgment to perform an operation may be referred to as an intelligent robot.

Robots can be classified into industrial, medical, home, military robots, etc., according to the purpose or field. The robot may include actuators or drives including motors to perform various physical operations, such as moving a robot joint. In addition, the movable robot may include wheels, brakes, propellers, etc. in the drive to travel on the ground or fly in the air by the drive.

The foregoing technical features may be applied to an apparatus supporting augmented reality.

Augmented reality is collectively referred to as Virtual Reality (VR), augmented Reality (AR), and Mixed Reality (MR). VR technology is a computer graphics technology that provides real world objects and background only in CG images, AR technology is a computer graphics technology that provides virtual CG images on real object images, and MR technology is a computer graphics technology that provides virtual objects mixed and combined with the real world.

MR technology is similar to AR technology in that real and virtual objects can be displayed together. However, in the AR technique, a virtual object is used as a supplement to a real object, whereas in the MR technique, a virtual object and a real object are used as equivalent states.

XR technology may be applied to Head Mounted Displays (HMDs), head Up Displays (HUDs), mobile phones, tablets, laptops, desktop computers, televisions, digital signage, and the like. Devices employing XR technology may be referred to as XR devices.

The claims disclosed in this specification may be combined in various ways. For example, the technical features in the method claims of the present specification may be combined to be implemented as an apparatus, and the technical features in the apparatus claims of the present specification may be combined to be implemented by a method. Furthermore, the technical features in the method claims and the apparatus claims of the present specification may be combined to be implemented as an apparatus, and the technical features in the method claims and the apparatus claims of the present specification may be combined to be implemented by a method.

Claims

1. A method in a wireless local area network, WLAN, system, the method comprising the steps of:

receiving, by a receiving multi-link device MLD, a downlink DL frame from a transmitting MLD; and

transmitting UL frames by the receiving MLD to the transmitting MLD,

wherein the DL frame includes BSR information for the receiving MLD,

wherein the BSR information for the receiving MLD is included in a buffer status subfield of a quality of service QoS control field, and

wherein the BSR information for the receiving MLD is traffic information for the receiving MLD buffered in the transmitting MLD.

2. The method of claim 1, wherein the buffer status subfield includes a reserved field and first, second and third subfields,

Wherein the reserved field includes information regarding whether the buffer status subfield includes the BSR information for the receiving MLD,

wherein the first subfield includes information on whether an access point power saving AP PS buffer status is specified.

3. The method of claim 2, wherein when the reserved field is set to 1, the BSR information for the receiving MLD is included in the buffer status subfield,

wherein the second subfield comprises information about an access category AC of traffic buffered in the transmitting MLD having the highest priority for the receiving MLD,

wherein the third subfield includes information about a total buffer size of traffic buffered in the transmitting MLD for the receiving MLD.

4. The method of claim 3, wherein the total buffer size for the traffic of the receiving MLD is rounded up to the nearest multiple of 4096 octets, and is set in units of 4096 octets,

wherein when the third subfield is set to 15, it is determined that a total buffer size for traffic of the received MLD is greater than 57344 octets,

Wherein when the first subfield is set to 1 and the third subfield is set to 0, the third subfield includes information that the AC for the highest priority traffic does not have buffered traffic.

5. The method of claim 2, wherein when the first subfield is set to 0, it is determined that the AP PS buffer status is not specified, and the second subfield and the third subfield are reserved.

6. The method of claim 1, wherein the DL frame further comprises a first information field, a second information field, or a third information field,

wherein the first information field includes information on whether low-delay traffic is included in traffic for the receiving MLD buffered in the transmitting MLD,

wherein the second information field includes information on whether time-sensitive traffic is included in traffic for the receiving MLD buffered in the transmitting MLD,

wherein the third information field includes information about a service identifier ID of a service buffered in the transmitting MLD for the receiving MLD,

wherein at least one STA included in the receiving MLD transitions to an awake state based on the first information field, the second information field, or the third information field.

7. The method of claim 6, wherein the UL frame includes information indicating that the at least one STA is in the awake state.

8. A receiving multi-link device, MLD, in a wireless local area network, WLAN, system, the receiving MLD comprising:

a memory;

a transceiver; and

a processor operatively connected to the memory and the transceiver,

wherein the processor is configured to:

receiving a downlink DL frame from a transmitting MLD; and is also provided with

UL frames are transmitted to the transmitting MLD,

wherein the DL frame includes BSR information for the receiving MLD,

9. A method in a wireless local area network, WLAN, system, the method comprising the steps of:

transmitting, by a transmitting multi-link device MLD, a downlink DL frame to a receiving MLD; and

receiving UL frames by the transmitting MLD from the receiving MLD,

wherein the DL frame includes BSR information for the receiving MLD,

10. The method of claim 9, wherein the buffer status subfield includes a reserved field and first, second and third subfields,

11. The method of claim 10, wherein when the reserved field is set to 1, the BSR information for the receiving MLD is included in the buffer status subfield,

12. The method of claim 11, wherein a total buffer size for the traffic of the receiving MLD is rounded up to a nearest multiple of 4096 octets, and is set in units of 4096 octets,

13. The method of claim 10, wherein when the first subfield is set to 0, it is determined that the AP PS buffer status is not specified, and the second subfield and the third subfield are reserved.

14. The method of claim 9, wherein the DL frame further comprises a first information field, a second information field, or a third information field,

15. The method of claim 14, wherein the UL frame includes information indicating that the at least one STA is in the awake state.

16. A transmitting multi-link device, MLD, in a wireless local area network, WLAN, system, the transmitting MLD comprising:

a memory;

a transceiver; and

a processor operatively connected to the memory and the transceiver,

wherein the processor is configured to:

transmitting a downlink DL frame to a receiving MLD; and is also provided with

Receiving an UL frame from the receiving MLD,

wherein the DL frame includes BSR information for the receiving MLD,

17. A computer-readable medium comprising instructions for execution by at least one processor and performing a method comprising:

receiving a downlink DL frame from a transmitting multi-link device MLD; and

UL frames are transmitted to the transmitting MLD,

wherein the DL frame includes BSR information for the receiving MLD,

18. An apparatus in a wireless local area network, WLAN, system, the apparatus comprising:

a memory; and

a processor operatively connected to the memory,

wherein the processor is configured to:

receiving a downlink DL frame from a transmitting multi-link device MLD; and is also provided with

UL frames are transmitted to the transmitting MLD,

wherein the DL frame includes BSR information for the receiving MLD,

wherein BSR information for the received MLD is included in a buffer status subfield of a quality of service QoS control field, and