WO2022045840A1 - Connection method for connectionless communication node in wireless lan - Google Patents

Abstract

Disclosed is a connection method for a connectionless communication node in wireless LAN. An operating method of an AP comprises the steps of: transmitting a first frame to discover an STA; receiving, from one or more STAs, in response to the first frame, a second frame indicating that the STA exists; and transmitting, to the one or more STAs, a third frame including resource allocation information.

Description

Connection method for connectionless communication node in wireless LAN

The present invention relates to a wireless local area network (WLAN) communication technology, and more particularly, to a connection technology for a connectionless communication node.

Recently, as the spread of mobile devices has been expanded, a wireless local area network (WLAN) technology capable of providing a fast wireless communication service to mobile devices has been in the spotlight. The wireless LAN technology may be a technology that enables mobile devices such as a smart phone, a smart pad, a laptop computer, a portable multimedia player, and an embedded device to wirelessly access the Internet based on a wireless communication technology in a short distance.

A standard using a wireless LAN technology is mainly being developed as an IEEE 802.11 standard by the Institute of Electrical and Electronics Engineers (IEEE). An early version of the IEEE 802.11 standard can support 1 to 2 mega bits per second (Mbps). After that, the IEEE 802.11n standard and IEEE 802.11ac standard supporting a wide channel bandwidth and improved throughput, and the IEEE 802.11ax standard supporting improved frequency efficiency in a dense environment were developed.

Recently, as applications requiring higher throughput and applications requiring real-time transmission occur, the IEEE 802.11be standard, which is an Extreme High Throughput (EHT) wireless LAN technology, is being developed. The goal of the IEEE 802.11be standard may be to support a high throughput of 30 Gbps. The IEEE 802.11be standard may support a technique for reducing transmission delay. In addition, the IEEE 802.11be standard is a more extended frequency bandwidth (eg, 320 MHz bandwidth), multi-link (Multi-link) including an operation using a multi-band operation and aggregation (aggregation) operation, It may support multiple access point (AP) transmission operation, and/or efficient retransmission operation (eg, Hybrid Automatic Repeat Request (HARQ) operation).

In a communication system supporting multiple links, an unassociated communication node and/or a low-power communication node (eg, a communication node performing a low-power operation) may exist. When an access point (AP) and a station (STA) are unaware of the existence of an unconnected communication node and/or a low-power communication node, the performance of the communication system may be degraded. Methods to solve these problems will be needed.

On the other hand, the technology that is the background of the invention is written to improve the understanding of the background of the invention, and may include content that is not already known to those of ordinary skill in the art to which this technology belongs.

An object of the present invention to solve the above problems is to provide a connection method for a connectionless communication node in a wireless LAN.

In order to achieve the above object, a method of operating an AP according to a first embodiment of the present invention includes transmitting a first frame to discover an STA, and indicating that the STA exists in response to the first frame. receiving a second frame from one or more STAs; and transmitting a third frame including resource allocation information to the one or more STAs.

The first frame may include information requesting to confirm the presence of the STA, and the first frame may be transmitted through multiple links.

The second frame may include a preamble and an STF, the STF may be set in units of frequency tones, and a first STF of a first STA among the one or more STAs may be received on a frequency tone #p, , a second STF of a second STA among the one or more STAs may be received at frequency tone #p, and k and p may be different natural numbers.

A frequency band in which the first frame and the second frame are transmitted may include a plurality of frequency tones, and when the communication system supports multiple links, at least two frequency tones among the plurality of frequency tones are It can be set for each link.

If the second frame is not received within a preset time from the transmission time of the first frame, it may be determined that the STA does not exist.

The method of operating the AP may further include performing an association procedure with the one or more STAs based on the resource allocation information included in the third frame, and the third frame performs the association procedure It may further include an identifier of each of the one or more STAs.

The performing the connection procedure may further include receiving a probe request frame from the one or more STAs.

The performing the connection procedure may further include transmitting a beacon frame or a non-requested probe response frame.

The performing of the connection procedure may include transmitting a beacon frame or a non-request probe response frame including the system information when the second frame includes an STF requesting system information.

The method of operating the AP may further include receiving a trigger frame requesting to perform the discovery procedure of the STA from the master AP, the first frame may be transmitted when the trigger frame is received, The AP may operate as a relay AP.

In order to achieve the above object, there is provided a method of operating an STA according to a second embodiment of the present invention, comprising: receiving, from an AP, a first frame including information requesting to confirm the existence of the STA; and a response to the first frame transmitting a second frame indicating that the STA exists to the AP, and receiving a third frame including resource allocation information from the AP.

The second frame may include a preamble and an STF, the STF may be transmitted using a frequency tone, and the frequency tone may be configured for a link in which the STA operates.

The method of operating the STA may further include performing an association procedure with the AP based on the resource allocation information included in the third frame, and the third frame is the STA of the STA performing the association procedure. It may further include an identifier.

The performing the connection procedure may further include transmitting a probe request frame to the AP using a resource indicated by the resource allocation information.

The performing the connection procedure may further include receiving a beacon frame or a non-requested probe response frame from the AP.

The performing of the connection procedure may include, when the second frame includes an STF requesting system information, receiving a beacon frame or a non-requested probe response frame including the system information from the AP. there is.

An AP according to a third embodiment of the present invention for achieving the above object includes a processor, a memory in electronic communication with the processor, and instructions stored in the memory, wherein when the instructions are executed by the processor, The instructions indicate that the AP transmits a first frame including information requesting to confirm the existence of the STA through multiple links in order to discover the STA, and that the STA exists in response to the first frame. and receive a second frame indicating the second frame from the one or more STAs, and cause transmission of a third frame including resource allocation information to the one or more STAs.

The second frame may include a preamble and an STF, the STF may be set in units of frequency tones, and a first STF of a first STA among the one or more STAs may be received on a frequency tone #p, , a second STF of a second STA among the one or more STAs may be received at frequency tone #p, and k and p may be different natural numbers.

The instructions may be executed to further cause the AP to perform an association procedure with the one or more STAs based on the resource allocation information included in the third frame, wherein the third frame performs the association procedure It may further include an identifier of each of the one or more STAs.

When performing the connection procedure, the instructions cause the AP to perform "receiving a probe request frame from the one or more STAs" or "transmitting a beacon frame or a non-requested probe response frame" can be executed

According to the present application, an access point (AP) can check the state of an uplink frame of a plurality of STAs (stations) by using a multi-user communication method based on orthogonal frequency division multiplexing (OFDM) tones, and the confirmed Based on the state, the STAs may allocate radio resources for the uplink frame. According to this operation, the execution time of the channel access operation can be reduced, and the channel access success probability can be improved. In a communication system supporting multiple links, "state of a terminal in each link" and/or "state of each link" can be accurately identified by using a multi-user communication method based on OFDM tones. Accordingly, the performance of the communication system can be improved.

1 is a block diagram illustrating a first embodiment of a communication node constituting a wireless LAN system.

2 is a conceptual diagram illustrating a first embodiment of multiple links established between MLDs.

3 is a flowchart illustrating a first embodiment of a negotiation procedure for a multi-link operation in a wireless LAN system.

4 is a conceptual diagram illustrating a first embodiment of a method for discovering an unassociated STA in a WLAN system.

5 is a timing diagram illustrating a second embodiment of a method for discovering an unconnected STA in a wireless LAN system.

6 is a block diagram illustrating a first embodiment of an NFRP frame in a wireless LAN system.

7 is a block diagram illustrating a first embodiment of a trigger frame in a wireless LAN system.

8 is a timing diagram illustrating a third embodiment of a method for discovering an unconnected STA in a wireless LAN system.

9 is a timing diagram illustrating a fourth embodiment of a method for discovering an unconnected STA in a wireless LAN system.

10 is a timing diagram illustrating a first embodiment of a low-power communication method in a wireless LAN system.

11 is a timing diagram illustrating a fifth embodiment of a method for discovering an unconnected STA in a wireless LAN system.

12 is a block diagram illustrating a first embodiment of an NFRP presence confirmation frame in a wireless LAN system.

Since the present invention can have various changes and can have various embodiments, specific embodiments are illustrated in the drawings and described in detail. However, this is not intended to limit the present invention to specific embodiments, and it should be understood to include all modifications, equivalents and substitutes included in the spirit and scope of the present invention.

Terms such as first, second, etc. may be used to describe various elements, but the elements should not be limited by the terms. The above terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, a first component may be referred to as a second component, and similarly, a second component may also be referred to as a first component. and/or includes a combination of a plurality of related listed items or any of a plurality of related listed items.

When an element is referred to as being “connected” or “connected” to another element, it is understood that it may be directly connected or connected to the other element, but other elements may exist in between. it should be On the other hand, when it is said that a certain element is "directly connected" or "directly connected" to another element, it should be understood that the other element does not exist in the middle.

The terms used in the present application are only used to describe specific embodiments, and are not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly dictates otherwise. In the present application, terms such as “comprise” or “have” are intended to designate that a feature, number, step, operation, component, part, or combination thereof described in the specification exists, but one or more other features It should be understood that this does not preclude the existence or addition of numbers, steps, operations, components, parts, or combinations thereof.

Unless defined otherwise, all terms used herein, including technical and scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in a commonly used dictionary should be interpreted as having a meaning consistent with the meaning in the context of the related art, and should not be interpreted in an ideal or excessively formal meaning unless explicitly defined in the present application. does not

Hereinafter, preferred embodiments of the present invention will be described in more detail with reference to the accompanying drawings. In explaining the present invention, in order to facilitate the overall understanding, the same reference numerals are used for the same components in the drawings, and duplicate descriptions of the same components are omitted.

In the following, a wireless communication system to which embodiments according to the present invention are applied will be described. The wireless communication system to which the embodiments according to the present invention are applied is not limited to the contents described below, and the embodiments according to the present invention can be applied to various wireless communication systems. A wireless communication system may be referred to as a “wireless communication network”.

1 is a block diagram illustrating a first embodiment of a communication node constituting a wireless LAN system.

Referring to FIG. 1 , a communication node 100 may be an access point, a station, an access point (AP) multi-link device (MLD), or a non-AP MLD. An access point may mean an AP, and a station may mean an STA or a non-AP STA. The operating channel width supported by the access point may be 20 MHz (megahertz), 80 MHz, 160 MHz, or the like. The operating channel width supported by the station may be 20 MHz, 80 MHz, etc.

The communication node 100 may include at least one processor 110 , a memory 120 , and a plurality of transmission/reception devices 130 connected to a network to perform communication. The transceiver 130 may be referred to as a transceiver, a radio frequency (RF) unit, an RF module, or the like. In addition, the communication node 100 may further include an input interface device 140 , an output interface device 150 , a storage device 160 , and the like. Each of the components included in the communication node 100 may be connected by a bus 170 to perform communication with each other.

However, each of the components included in the communication node 100 may be connected through an individual interface or a separate bus centered on the processor 110 rather than the common bus 170 . For example, the processor 110 may be connected to at least one of the memory 120 , the transceiver 130 , the input interface device 140 , the output interface device 150 , and the storage device 160 through a dedicated interface. .

The processor 110 may execute a program command stored in at least one of the memory 120 and the storage device 160 . The processor 110 may mean a central processing unit (CPU), a graphics processing unit (GPU), or a dedicated processor on which methods according to embodiments of the present invention are performed. Each of the memory 120 and the storage device 160 may be configured of at least one of a volatile storage medium and a non-volatile storage medium. For example, the memory 120 may be configured as at least one of a read only memory (ROM) and a random access memory (RAM).

2 is a conceptual diagram illustrating a first embodiment of a multi-link configured between multi-link devices (MLDs).

Referring to FIG. 2 , the MLD may have one medium access control (MAC) address. In embodiments, MLD may refer to AP MLD and/or non-AP MLD. The MAC address of the MLD may be used in the multi-link setup procedure between the non-AP MLD and the AP MLD. The MAC address of the AP MLD may be different from the MAC address of the non-AP MLD. Access point(s) associated with AP MLD may have different MAC addresses, and station(s) associated with non-AP MLD may have different MAC addresses. Access points in the AP MLD having different MAC addresses may be in charge of each link and may perform the role of an independent access point (AP).

Stations in the non-AP MLD having different MAC addresses may be in charge of each link and may perform the role of an independent station (STA). Non-AP MLD may be referred to as STA MLD. MLD may support simultaneous transmit and receive (STR) operation. In this case, the MLD may perform a transmit operation on link 1 and may perform a receive operation on link 2 . An MLD supporting the STR operation may be referred to as an STR MLD (eg, STR AP MLD, STR non-AP MLD). In embodiments, a link may mean a channel or a band. A device that does not support the STR operation may be referred to as an NSTR (non-STR) AP MLD or an NSTR non-AP MLD (or NSTR STA MLD).

MLD may transmit and receive frames in multiple links by using a non-contiguous bandwidth extension scheme (eg, 80 MHz + 80 MHz). Multi-link operation may include multi-band transmission. The AP MLD may include a plurality of access points, and the plurality of access points may operate on different links. Each of the plurality of access points may perform function(s) of a lower MAC layer. Each of the plurality of access points may be referred to as a “communication node” or “sub-entity”. A communication node (ie, an access point) may operate under the control of a higher layer (or the processor 110 illustrated in FIG. 1 ). A non-AP MLD may include a plurality of stations, and the plurality of stations may operate on different links. Each of the plurality of stations may be referred to as a “communication node” or “sub-entity”. A communication node (ie, a station) may operate under the control of a higher layer (or the processor 110 illustrated in FIG. 1 ).

MLD may perform communication in multi-band. For example, MLD may perform communication using a 40 MHz bandwidth according to a channel extension method (eg, a bandwidth extension method) in a 2.4 GHz band, and communicate using a 160 MHz bandwidth according to a channel extension method in a 5 GHz band can be performed. MLD may perform communication using a 160 MHz bandwidth in a 5 GHz band, and may perform communication using a 160 MHz bandwidth in a 6 GHz band. One frequency band (eg, one channel) used by the MLD may be defined as one link. Alternatively, a plurality of links may be configured in one frequency band used by the MLD. For example, the MLD may establish one link in the 2.4 GHz band and two links in the 6 GHz band. Each link may be referred to as a first link, a second link, a third link, and the like.

The MLD (eg, AP MLD and/or non-AP MLD) may establish multiple links by performing an access procedure and/or a negotiation procedure for multi-link operation. In this case, the number of links and/or a link to be used among multiple links may be set. The non-AP MLD (eg, a station) may check band information capable of communicating with the AP MLD. In a negotiation procedure for a multi-link operation between the non-AP MLD and the AP MLD, the non-AP MLD may configure one or more links among links supported by the AP MLD to be used for the multi-link operation. A station that does not support multi-link operation (eg, an IEEE 802.11a/b/g/n/ac/ax station) may be connected to one or more of the multi-links supported by the AP MLD.

If the band spacing between multiple links (eg, the band spacing of link 1 and link 2 in the frequency domain) is sufficient, the MLD may perform the STR operation. For example, the MLD may transmit a physical layer convergence procedure (PLCP) protocol data unit (PPDU) 1 using link 1 among multiple links, and may receive PPDU 2 using link 2 among multiple links. On the other hand, if the MLD performs the STR operation when the band spacing between multiple links is insufficient, in-device coexistence (IDC) interference, which is interference between multiple links, may occur. Therefore, when the bandwidth between multiple links is insufficient, the MLD may not be able to perform the STR operation.

For example, multiple links including link 1, link 2, and link 3 may be configured between the AP MLD and the non-AP MLD 1. If the band spacing between link 1 and link 3 is sufficient, AP MLD may perform STR operation using link 1 and link 3. That is, the AP MLD may transmit a frame using link 1 and may receive a frame using link 3 . If the band spacing between link 1 and link 2 is not sufficient, AP MLD may not be able to perform STR operation using link 1 and link 2. If the band spacing between link 2 and link 3 is not sufficient, AP MLD may not be able to perform STR operation using link 2 and link 3.

3 is a flowchart illustrating a first embodiment of a negotiation procedure for a multi-link operation in a wireless LAN system.

Referring to FIG. 3 , an access procedure between a station (STA) and an access point (AP) in an infrastructure basic service set (BSS) is a probe step of an access point, and an authentication step between the station and the detected access point (authentication) step), and an association step between the station and the authenticated access point.

In the detection step, the station may detect one or more access points using a passive scanning method or an active scanning method. When the passive scanning method is used, the station may detect one or more access points by overhearing a beacon frame transmitted by the one or more access points. When the active scanning method is used, the station may transmit a probe request frame and receive one or more access points by receiving a probe response frame that is a response to the probe request frame from one or more access points. points can be detected.

If one or more access points are detected, the station may perform an authentication step with the detected access point(s). In this case, the station may perform an authentication step with a plurality of access points. An authentication algorithm according to the IEEE 802.11 standard may be classified into an open system algorithm for exchanging two authentication frames, a shared key algorithm for exchanging four authentication frames, and the like.

The station may transmit an authentication request frame based on an authentication algorithm according to the IEEE 802.11 standard and communicate with the access point by receiving an authentication response frame that is a response to the authentication request frame from the access point. authentication can be completed.

When authentication with the access point is completed, the station may perform a connection step with the access point. In this case, the station may select one access point from among itself and the access point(s) that have performed the authentication step, and may perform the connection step with the selected access point. That is, the station may transmit an association request frame to the selected access point, and receive an association response frame that is a response to the association request frame from the selected access point to establish a connection with the selected access point. can be completed

Meanwhile, a multi-link operation may be supported in a wireless LAN system. The MLD may include one or more STAs associated with the corresponding MLD. The MLD may be a logical entity. MLD can be classified into AP MLD and non-AP MLD. Each STA associated with the AP MLD may be an AP, and each STA associated with the non-AP MLD may be a non-AP STA. In order to configure multiple links, a multiple link discovery procedure, a multiple link setup procedure, and the like may be performed. The multi-link discovery procedure may be performed in the detection phase between the station and the access point. In this case, the ML multi-link information element (ML IE) may be included in a beacon frame, a probe request frame, and/or a probe response frame.

For example, to perform a multi-link operation, a multi-link operation is used between an access point (eg, an AP associated with an MLD) and a station (eg, a non-AP STA associated with an MLD) in the detection phase. Information indicating whether it is possible and available link information can be exchanged. In a negotiation procedure for multi-link operation (eg, multi-link setup procedure), an access point and/or station may transmit information of a link to be used for multi-link operation. The negotiation procedure for multi-link operation may be performed in an access procedure (eg, connection step) between the station and the access point, and the information element(s) necessary for multi-link operation are in an action frame in the negotiation procedure. may be set or changed by

In addition, in an access procedure (eg, a connection step) between the station and the access point, available link(s) of the access point may be established, and an identifier (ID) may be assigned to each link. Thereafter, in a negotiation procedure and/or a change procedure for multi-link operation, information indicating whether each link is activated may be transmitted, and the information may be expressed using a link ID.

Information indicating whether multi-link operation is available can be transmitted and received in the exchange procedure of a capability information element (eg, extremely high throughput (EHT) capability information element) between the station and the access point. there is. The capability information element includes information of a supporting band, information of a supporting link (eg, ID and/or number of supporting links), information of links capable of STR operation (eg, band information of links) , interval information of links), and the like. In addition, the capability information element may include information indicating individually a link capable of STR operation.

4 is a conceptual diagram illustrating a first embodiment of a method for discovering an unassociated STA in a WLAN system.

Referring to FIG. 4 , an AP (eg, a relay AP) may check whether an unconnected STA exists. That is, the AP may perform the discovery procedure of the unconnected STA. A non-connected STA may mean an STA that is not connected to an AP. When a non-connected STA exists, the AP may generate a beacon frame or probe response frame including information necessary for the connection procedure of the non-connected STA, and may transmit the beacon frame or probe response frame.

The AP may transmit a null data packet (NDP) feedback request poll (NFRP) frame. The NFRP frame may include information requesting confirmation of the existence of a non-connected STA. STA(s) (eg, unconnected STA) may receive an NFRP frame from the AP, and may transmit an NDP feedback report (NFR) frame to the AP in response to the NFRP frame. The NFR frame may indicate that an unconnected STA exists. In addition, the NFR frame may indicate "that an STA (eg, a non-connected STA) wants to perform an association procedure". The AP may receive the NFR frame from the STA(s). The AP may confirm the existence of a non-connected STA (eg, a STA to perform an association procedure) based on the NFR frame. In embodiments, the NFRP frame may be referred to as a first frame, and the NFR frame may be referred to as a second frame.

In order for a plurality of STAs to transmit NFR frames, the NFRP frame may be transmitted in the form of a trigger frame. The NFRP frame may be referred to as an NFRP trigger frame (TF). NFR frames of a plurality of STAs may be multiplexed in the frequency domain. For example, the NFR frame of STA1 (eg, some signals included in the NFR frame) may be transmitted through frequency tone #1, and the NFR frame of STA2 (eg, some signals included in the NFR frame) may be transmitted. may be transmitted on frequency tone #2. NFR frames may be multiplexed in an Orthogonal Frequency Division Multiple Access (OFDMA) scheme. The NFR frame may be transmitted in the form of a short training field (STF).

In order to expand an area for confirming the existence of a non-connected STA, the AP may designate a STA that performs an AP function among STAs. An STA performing an AP function may be referred to as a “relay AP”. The AP may transmit a trigger frame requesting confirmation of the existence of the unconnected STA to the relay AP. When the corresponding trigger frame is received from the AP, the relay AP may transmit an NFRP frame and may receive an NFR frame that is a response of the NFRP frame from the STA(s).

5 is a timing diagram illustrating a second embodiment of a method for discovering an unconnected STA in a wireless LAN system.

Referring to FIG. 5 , the AP (eg, the AP included in the AP MLD) is "unassociated STA(s) (Unassociated STA)" "STA(s) having uplink traffic to transmit to the AP", or "random access" In order to discover "STA(s) to perform a (random access) procedure", an NFRP frame (eg, NFRP TF) may be transmitted in one link (eg, a first link) among multiple links. Alternatively, the NFRP frame may be transmitted simultaneously through multiple links. The disconnected STA(s) may be STA(s) not connected to the AP. The NFRP frame may trigger transmission of a signal and/or frame (eg, NFR frame) indicating the existence of an unconnected STA. The NFR frame may be transmitted based on the OFDMA scheme. The NFR frame (eg, some signals included in the NFR frame) may be transmitted to the AP through a frequency tone. The NFRP frame may be configured as follows.

6 is a block diagram illustrating a first embodiment of an NFRP frame in a wireless LAN system.

Referring to FIG. 6 , the NFRP frame may include a MAC header, common information, a user information list, and/or a frame check sequence (FCS). The common information may include a trigger type field, a PPDU length field, a TXOP duration field, a full bandwidth field, and/or a TX power field. The trigger type field may indicate the type of the NFRP frame (ie, NFRP). The trigger type field may trigger transmission of an NFR frame by a non-connected STA or connected STAs, and the NFR frame may indicate “presence of a non-connected STA” or “presence of uplink traffic to be transmitted to the AP”. The user information list may include one or more user information fields. The user information field may include a starting association identification (AID) and/or a feedback type. When triggering a non-connection STA, the starting AID may be set to a reserved value (eg, a specific value) that is not assigned to the STA. For example, the starting AID may be set to 2045. The starting AID set to 2045 may indicate (or request) confirmation of existence of a non-connected STA. The feedback type may indicate confirmation of the existence of an unconnected STA. Or, when triggering the connected STA, the starting AID is "the AID of the triggering target STA" or "a reserved value not assigned to the connecting STA to perform random transmission (eg, random access procedure)" can be set. The reserved value may indicate that the connected STA performs a random transmission operation. For example, the starting AID may be set to 2046. The start AID set to 2046 may indicate (or request) confirmation of the existence of uplink traffic of the connecting STA. The feedback type may indicate confirmation of existence of uplink traffic.

Referring back to FIG. 5 , a “non-connected STA” or “a STA having an uplink frame to be transmitted to the AP among connected STAs (hereinafter, referred to as “uplink STA”)” may receive an NFRP frame from the AP. "When the NFRP frame requests confirmation of the existence of a non-connected STA", "When the non-connected STA wants to connect with the AP that transmitted the NFRP frame", and/or "If the NFRP frame requests confirmation of the existence of an uplink STA case", the unconnected STA or the uplink STA may transmit a response frame (eg, an NFR frame) to the NFRP frame to the AP. The unconnected STA or the uplink STA may select one frequency tone from among available frequency tones in a frequency band, and may transmit an NFR frame using the selected frequency tone.

The NFR frame may include only the STF. Alternatively, the NFR frame may include a preamble and an STF, and the preamble may include a legacy preamble (L-Pre) and/or an EHT preamble (EHT-Pre). The STF may be set in units of frequency tones. The STF set in units of frequency tones may be referred to as “per-tone STF”. For example, STA1 may transmit per-tone STF on frequency tone #k, and STA2 may transmit per-tone STF on frequency tone #p. k and p may be different natural numbers. When the NFR frame includes a preamble and a per-tone STF, the size of the frequency band in which the preamble is transmitted may be different from the size of the frequency band in which the per-tone STF is transmitted. For example, the frequency band in which the preamble is transmitted may be larger than the frequency band in which the per-tone STF is transmitted.

Frequency tones may be set for each link. For example, if there are 40 frequency tones (eg, frequency tones #1 to #40) in the entire frequency band, frequency tones #1 to #10 may be set for the first link, and frequency tones #11 to #20 may be configured for the second link, frequency tones #21 to #30 may be configured for the third link, and frequency tones #31 to #40 may be configured for the fourth link. there is. The non-connected STA may select one frequency tone among frequency tones set in a preferred link among multiple links (or a link in which the non-connected STA operates), and signal (eg, NFR frame) using the selected frequency tone. can be transmitted.

If the NFR frame is not received within a preset time (eg, short interframe space (SIFS)) from the transmission time of the NFRP frame, the AP may determine that there is no unconnected STA or uplink STA, and additionally An operation (eg, a connection procedure with an unconnected STA or a resource allocation procedure with an uplink STA) may not be performed.

"When additional information (eg, STA identifier (MAC address, AID, etc.)) of an STA (eg, unconnected STA or uplink STA) is required", "when it is necessary to receive a request from an STA" or When "allocation of transmission resources for uplink traffic or Buffer Status Report (BSR) of the STA is required", the AP may transmit a trigger frame to provide a transmission opportunity to the STA that has transmitted the NFR frame. Alternatively, the trigger frame may be transmitted to perform a connection procedure with the unconnected STA(s). In this case, the trigger frame may include information necessary for the connection procedure (eg, an identifier and/or resource allocation information indicating an unconnected STA to perform the connection procedure). The trigger frame may be transmitted over "multi-link" or "link(s) on which per-tone STF was received". The trigger frame may be set as follows.

7 is a block diagram illustrating a first embodiment of a trigger frame in a wireless LAN system.

Referring to FIG. 7 , the trigger frame may include a MAC header, common information, a user information list, and/or an FCS. The common information may include a trigger type field, a PPDU length field, a TXOP duration field, a full bandwidth field, and/or a TX power field. The trigger type field may indicate the type (eg, basic) of the trigger frame. The user information list may include one or more user information fields. The user information field may include an index of the per-tone STF included in the NFR frame received from the unconnected STA or the uplink STA. The per-tone STF index (ie, the index of the per-tone STF) may be used to identify a non-connected STA or an uplink STA, and the AP selects a non-connected STA or an uplink STA identified by the per-tone STF index. For example, a radio resource (eg, a resource unit (RU)) may be allocated. Resource allocation information indicating radio resources allocated by the AP may be included in the user information field.

Referring back to FIG. 5 , the AP may transmit a trigger frame by performing a new channel contention operation. The trigger frame may be transmitted on the first link. TXOP may be established by transmission of an NFRP frame. The TXOP may include up to a time required for an exchange procedure of frame(s) triggered by the trigger frame. In this case, the AP may transmit the trigger frame after a preset time (eg, SIFS) from the reception time of the NFR frame without performing a new channel contention operation. The trigger frame may include a per-tone STF index for identifying a non-connected STA or uplink STA and/or resource allocation information for the non-connected STA or uplink STA.

Unconnected STA(s) or uplink STA(s) (eg, unconnected STA(s) or uplink STA(s) that have transmitted an NFR frame) may receive a trigger frame from the AP, and the trigger frame It is possible to compare the per-tone STF index included in the per-tone STF index and the per-tone STF index transmitted by the unconnected STA(s) or the uplink STA(s). When the per-tone STF index included in the trigger frame is the same as the index of the per-tone STF transmitted by the non-connected STA(s) or uplink STA(s), the non-connected STA(s) or uplink STA(s) can check resource allocation information related to (or mapped to) the per-tone STF within the trigger frame. The unconnected STA(s) or the uplink STA(s) may transmit a probe request frame, a management frame, or a data frame to the AP using the resource indicated by the resource allocation information. A probe request frame transmitted by unconnected STA(s) may be transmitted to request system information. The management frame may include information requested from the AP.

After transmission of the trigger frame, the AP may receive frame(s) (eg, probe request frame, management frame, and/or data frame) from unconnected STA(s) or uplink STA(s). The AP may transmit a multi-STA block ACK (MBA) indicating the reception state of the unconnected STA(s) or the uplink STA(s). The unconnected STA(s) may receive the MBA from the AP, and may check the reception state of the frame(s) in the AP based on the MBA. After transmission of the MBA, when information transmission is requested by the disconnected STA(s), the AP receives a frame (eg, a beacon frame, a probe response frame, and / or an unsolicited probe response frame) may be transmitted to the unconnected STA(s). The non-requested probe response frame may mean a probe response frame transmitted without transmitting the probe request frame.

When a request to transmit the same information is received from non-connected STAs, the AP may transmit a frame including the same information in a broadcast manner. The beacon frame or the probe response frame may be transmitted in response to the probe request frame. If the TXOP secured by the NFRP frame is sufficient, the AP may transmit the frame after a preset time (eg, SIFS) from the transmission time of the MBA. Alternatively, when a new TXOP is required for transmission of the corresponding frame, the AP may perform a new channel contention operation to obtain a new TXOP, and in the new TXOP, a beacon frame, a probe response frame, and/or a non-request A probe response frame may be transmitted. The unconnected STA(s) may receive a beacon frame, a probe response frame, or a non-request probe response frame from the AP, and may check information included in the frame. When the above-described operations are completed, a procedure for transmitting and receiving a connection request/response frame may be performed between the AP and the unconnected STA(s).

On the other hand, when a plurality of unconnected STAs or uplink STAs transmit a per-tone STF using the same frequency tone, a resource allocated for one per-tone STF is used for frame transmission of a plurality of unconnected STAs. can be used In this case, collisions between frames may occur. When a frame reception error occurs, the AP may transmit a trigger frame. Here, the trigger frame may be an uplink OFDMA random access (UORA) trigger frame (TF). Unconnected STAs or uplink STAs (eg, unconnected STAs or uplink STAs having transmission collision) that have received the UORA TF may randomly select a subchannel and transmit a frame in the selected subchannel. can In this case, occurrence of additional collisions between frames can be prevented.

8 is a timing diagram illustrating a third embodiment of a method for discovering an unconnected STA in a wireless LAN system.

Referring to FIG. 8 , an AP (eg, an AP included in an AP MLD) uses an NFRP frame (eg, a first link) in one link (eg, a first link) among multiple links to discover unconnected STA(s). For example, NFRP TF) may be transmitted. Alternatively, the NFRP frame may be transmitted simultaneously through multiple links. The NFRP frame may be configured the same or similar to the NFRP frame shown in FIG. 6 . Prior to transmission of the NFRP frame, the AP may transmit a beacon frame. The disconnected STA(s) may be STA(s) not connected to the AP. The NFRP frame may trigger transmission of a signal and/or frame (eg, NFR frame) indicating the existence of an unconnected STA. The NFR frame indicating the existence of the unconnected STA may be transmitted to the AP through a frequency tone based on the OFDMA scheme.

The unconnected STA(s) may receive the NFRP frame from the AP, and may check information included in the NFRP frame. "When the NFRP frame requests confirmation of the existence of a non-connected STA" and/or "When the non-connected STA wants to connect with the AP that transmitted the NFRP frame", the non-connected STA responds to the NFRP frame , NFR frame) may be transmitted to the AP. The AP may receive an NFR frame from the unconnected STA(s), and may transmit a beacon frame, a probe response frame, and/or a non-request probe response frame. The disconnected STA(s) may receive a beacon frame, a probe response frame, and/or a non-requested probe response frame from the AP, obtain system information from the received frame, and communicate with the AP based on the system information. A connection procedure and an authentication procedure can be performed.

The first per-tone STF of the NFR frame may be used to request transmission of system information. A first frequency tone (eg, a frequency tone through which the first per-tone STF is transmitted) in a frequency band may be referred to as a “system information (SI) request tone”. Among the non-connected STAs, the non-connected STA(s) that have not received the system information may transmit a per-tone STF using the SI request tone. The AP may only determine whether a signal is detected in the SI request tone. For example, when a signal is detected in the SI request tone, the AP may determine that transmission of system information is requested. The AP may determine that transmission of system information is not requested when a signal is not detected in the SI request tone. Therefore, when a plurality of unconnected STAs transmit per-tone STF in the SI request tone, the AP may determine that the per-tone STF is detected in the SI request tone, and accordingly, it is determined that transmission of system information is necessary. can "SI (system information) request tone" may be set for each link. For example, the frequency tone through which the first per-tone STF is transmitted may be a frequency tone used for requesting system information of the first link, and the frequency tone through which the second per-tone STF is transmitted is the system of the second link. It may be a frequency tone used for requesting information, and the frequency tone through which the third per-tone STF is transmitted may be a frequency tone used for requesting system information of the third link.

When the per-tone STF is detected in the SI request tone, the AP may transmit a beacon frame or a probe response frame (eg, a non-requested probe response frame) including system information. The system information may include multi-link configuration information. When per-tone STFs are detected in frequency tones other than the SI request tone, the AP may check the number of unconnected STAs based on the detected number of per-tone STFs. For example, the number of detected per-tone STFs may be the same as the number of unconnected STAs.

When additional information of the unconnected STA(s) is required, the AP may transmit a trigger frame. The trigger frame may request transmission of additional information. The trigger frame may include information on radio resources allocated for each per-tone STF (eg, resource allocation information). For example, the trigger frame may be configured the same as or similar to the trigger frame shown in FIG. 7 . The user information field included in the user information list of the trigger frame may include per-tone STF index and/or resource allocation information, and a mapping relationship may be established between the per-tone STF index and resource allocation information. In addition, the trigger frame may include information indicating a request for additional information.

The unconnected STA(s) may receive a trigger frame from the AP, and may determine that transmission of additional information is requested based on information included in the trigger frame. The unconnected STA(s) may generate a frame including additional information, and may transmit the generated frame to the AP using a resource indicated by the trigger frame. Here, the frame may further include an identifier (eg, MAC address) of the unconnected STA as well as additional information. The AP may receive a frame from the unconnected STA(s) and may check additional information of the unconnected STA(s) included in the frame. In addition, the AP may obtain identifiers of unconnected STA(s) included in the frame.

On the other hand, if "a signal (eg, per-tone STF) is detected in the SI request tone and a signal (eg, per-tone STF) is detected also in a frequency tone other than the SI request tone", the AP wishes to connect It may be determined that unconnected STA(s) exist. In this case, the AP may transmit a trigger frame triggering transmission of the connection request frame to the unconnected STA(s). The trigger frame may be configured the same as or similar to the trigger frame shown in FIG. 7 . For example, the trigger frame may include an index of the detected per-tone STF and/or resource allocation information mapped to the corresponding index. The resource allocation information included in the trigger frame may indicate a resource for transmission of the connection request frame.

The unconnected STA(s) may receive a trigger frame from the AP, and when a per-tone STF index identical to its per-tone STF index exists in the trigger frame, resource allocation mapped to the per-tone STF index information can be checked. The unconnected STA(s) may transmit a connection request frame to the AP using the resource indicated by the confirmed resource allocation information.

The AP may receive a connection request frame from the disconnected STA(s), and may transmit an MBA indicating the reception state of the connection request frame to the disconnected STA(s). After that, the AP may transmit a connection response frame to the unconnected STA(s). A connection procedure between the AP and the unconnected STA(s) may be performed by the above-described operation. When the connection procedure is completed, an authentication procedure may be performed between the AP and the unconnected STA(s).

9 is a timing diagram illustrating a fourth embodiment of a method for discovering an unconnected STA in a wireless LAN system.

Referring to FIG. 9 , an AP (eg, an AP included in an AP MLD) may perform a discovery procedure of unconnected STAs using multiple links. In order to perform a discovery procedure in a wide area, an STA performing an AP function may be designated as a relay AP, and the relay AP may perform a discovery procedure of unconnected STAs. AP1 may be a master AP, and AP2, AP3, and AP4 may be relay APs. AP1 may perform a discovery procedure of unconnected STA(s) using multiple links in cooperation with relay AP(s). To support this operation, AP1 may transmit an AP trigger frame requesting the unconnected STA(s) to perform a discovery procedure to the STA(s). In addition, the AP trigger frame may request to operate as a relay AP.

The AP trigger frame may be configured the same as or similar to the trigger frame shown in FIG. 7 . The trigger type field included in the common information of the AP trigger frame may indicate the type of the AP trigger frame (eg, AP trigger). The user information field included in the user information list of the AP trigger frame may include an AP ID (or STA ID) and/or link allocation information (or channel allocation information). The AP ID (or STA ID) included in the user information field may be used to identify a relay AP (eg, an STA performing an AP function). Link allocation information (or channel allocation information) included in the user information field may indicate a link and/or a channel on which a discovery procedure of unconnected STA(s) is performed. The relay AP identified by the AP ID included in the user information field discovers unconnected STA(s) in the link and/or channel indicated by the link allocation information (or channel allocation information) included in the user information field. procedure can be performed.

The STA(s) may receive the AP trigger frame from AP1 and may check information included in the AP trigger frame. When the ID of the STA that has received the AP trigger frame is the same as the AP ID (or STA ID) included in the AP trigger frame, the corresponding STA may determine that it operates as a relay AP. The relay AP may perform a discovery procedure of unconnected STA(s) in a link (or channel) indicated by link assignment information of an AP trigger frame received from AP1. The discovery procedure of the disconnected STA(s) performed by the relay AP(s) may be performed the same or similar to the discovery procedure of the disconnected STA(s) shown in FIGS. 5 and/or 8 .

When the discovery procedure of unconnected STA(s) is performed by a plurality of relay APs, due to the limitation of the transmission area, the communication area of the relay AP does not overlap with the communication area of AP1 and/or the communication area of other relay APs. it may not be In this case, APs (eg, AP1 and/or relay AP(s)) may perform a discovery procedure of unconnected STA(s) in the same link instead of different links. For example, the AP trigger frame transmitted by AP1 in multiple links may have the same frame format, and the AP trigger frame may be transmitted at the same time in multiple links (or the same link). In the discovery procedure of unconnected STA(s) performed by APs, frame(s) may be transmitted at the same time point. To support this operation, the AP trigger frame may include information indicating a transmission time of the frame(s) in the discovery procedure of the unconnected STA(s).

"When the communication area is not wide and the AP MLD wants to perform the discovery procedure of the unconnected STA(s) using multiple links", the AP in charge of each link in the AP MLD discovers the unconnected STA(s) procedure can be performed. In this case, in the embodiment shown in FIG. 9, transmission of the AP trigger frame may be omitted, and each of AP2, AP3, and AP4 included in the AP MLD may be an AP in charge of each link.

10 is a timing diagram illustrating a first embodiment of a low-power communication method in a wireless LAN system.

Referring to FIG. 10 , the AP MLD may operate in a power saving mode in a plurality of links to save power. The AP operating in the power saving mode may be an STA (eg, a soft AP or a relay AP) performing an AP function. Even when a plurality of links are turned off for low-power operation, the beacon frame may be periodically transmitted on one or more links. "The link is in the off state" may mean "that the AP operating in the link is in a sleep state" or "the corresponding link is in a busy state", and "when the link is in an on state" "that" may mean "that the AP operating in the corresponding link is in an awake state" or "that the corresponding link is in an idle state".

AP1 of the AP MLD may periodically transmit a beacon frame in the first link. At the time of transmission of the beacon frame, the state of the first link may be changed to an on state. When the state of the first link is changed to the off state after transmission of the beacon frame in the first link, AP1 may not receive the data frame transmitted from the STA(s). To solve this problem, AP1 may transmit an NFRP frame after transmission of the beacon frame. The STA(s) may receive the NFRP frame of AP1 on the first link. If there is an STA having a data unit to be transmitted to AP1 (eg, AP MLD) among the STA(s), the STA indicates that there is a data unit to be transmitted to AP1 (eg, AP MLD) The NFR frame may be transmitted to AP1 on the first link.

AP1 may receive the NFR frame in the first link, and may determine that the STA that has transmitted the NFR frame has a data unit to be transmitted to AP1 (eg, AP MLD). The NFR frame may include L-Pre, EHT-Pre, and/or per-tone STF. The frequency tone(s) for each link can be set. For example, if there are 40 frequency tones (eg, frequency tones #1 to #40) in the entire frequency band, frequency tones #1 to #10 may be set for the first link, and frequency tones #11 to #20 may be configured for the second link, frequency tones #21 to #30 may be configured for the third link, and frequency tones #31 to #40 may be configured for the fourth link. there is.

For example, when an NFR frame (eg, per-tone STF) is detected in the tone(s) configured for the second link, the state of the second link may be changed to an on state. That is, the state of AP2 operating in the second link may transition to an awake state (eg, a normal state), and AP2 may prepare to receive a data frame. After the state of AP2 is transitioned to the awake state, AP2 may start an inactive timer. The inactive timer may be a timer used to check the existence of data thereafter. The inactive timer may be started when the state of the AP2 is first transitioned to the awake state. When a data frame is received, the inactive timer may normally expire. When the reception operation of the corresponding data frame is completed, a new inactive timer may be started. When a new data frame is not received before the expiration of the inactive timer, the state of the corresponding link (eg, the second link) may be transitioned to the off state. In this case, the state of AP2 operating in the second link may be transitioned to the sleep state. The operation according to the above-described inactive timer may be performed in the same or similar manner not only on the second link but also on other link(s).

On the other hand, when a plurality of per-tone STFs (eg, a plurality of NFR frames) are received, a plurality of STAs that want to transmit (eg, a plurality of STAs that have transmitted a plurality of per-tone STFs) ) may transmit a data frame (eg, a data unit) in the UL OFDMA scheme. After receiving the NFR frame, the AP(s) may transmit a buffer status report (BSR) trigger frame to the STA(s). The BSR trigger frame may request (eg, trigger) the transmission of the BSR. The BSR trigger frame may include a per-tone STF index (eg, an index of the per-tone STF included in the NFR frame). The per-tone STF index included in the BSR trigger frame may be used to indicate the STA that will transmit the BSR. In addition, the BSR trigger frame may include resource allocation information indicating a radio resource to which the BSR is to be transmitted.

The STA(s) may receive the BSR trigger frame, and when the per-tone STF index included in the BSR trigger frame indicates itself, the STA(s) may transmit the BSR to the AP(s). The BSR may be transmitted through a radio resource indicated by resource allocation information included in the BSR trigger frame. The BSR may include information indicating the size of a data unit to be transmitted by the STA(s). The AP(s) may receive the BSR from the STA(s), and may check the size of a data unit to be transmitted by the STA(s) based on information included in the BSR. The AP(s) may allocate resources in consideration of the size of the data unit indicated by the BSR, and transmit a TX trigger frame including resource allocation information to the STA(s) (eg, the STA(s) that transmitted the BSR). )) can be sent to The TX trigger frame may include an STA identifier (eg, AID) and/or resource allocation information, and a mapping relationship may be established between the STA identifier and resource allocation information.

The STA(s) may receive the TX trigger frame from the AP(s), and when the STA identifier included in the TX trigger frame and its own identifier are the same, the STA(s) may check resource allocation information mapped to the corresponding STA identifier. The STA(s) may transmit a data frame to the AP(s) using the resource indicated by the resource allocation information. The data frame may be transmitted based on the UL OFDMA scheme. A data transmission procedure based on the UL OFDMA scheme may be performed multiple times so that all STAs can transmit data frames.

11 is a timing diagram illustrating a fifth embodiment of a method for discovering an unconnected STA in a wireless LAN system.

Referring to FIG. 10 , when a data unit (eg, a buffered unit (BU)) to be transmitted to the STA(s) performing a low-power operation exists in the AP, the AP is a beacon including a traffic indication map (TIM). By sending a frame, it is possible to indicate that there is a data unit to be transmitted. When the value of the bit corresponding to the AID (eg, AID=1000, 2000, 3000, 4000) in the TIM (eg, bitmap) is set to 1, it is the STA MLD having the corresponding AID (eg, It may indicate that there is a data unit to be transmitted to the STA). One AID may be allocated for each STA MLD. The STA MLD may include a plurality of STAs having different MAC addresses, and the MAC address may be configured for each link in which the STA operates.

The AP may not be aware of available links (eg, the state of the STA in each link). In order to check the available link, the AP may transmit an NFRP presence check (presence check) frame. The NFRP presence confirmation frame may be configured as follows.

12 is a block diagram illustrating a first embodiment of an NFRP presence confirmation frame in a wireless LAN system.

12, the NFRP frame may include a MAC header, common information, user information list, and / or FCS. The common information may include a trigger type field, a PPDU length field, a TXOP duration field, a full bandwidth field, and/or a TX power field. The trigger type field may indicate the type of the NFRP presence confirmation frame (eg, NFRP presence confirmation). The user information list may include one or more user information fields. The user information field may include an AID and/or a feedback type.

The number of user information fields included in the user information list may be the same as the number of bits set to 1 in the TIM of the beacon frame. For example, when the values of bits corresponding to "AID = 1000, 2000, 3000, and 4000" in the TIM of the beacon frame are set to 1, the user information list includes four user information fields (eg, user information field 1, user information field 2, user information field 3, and user information field 4). User information field 1 may include "AID = 1000" and/or "feedback type indicating sleep existence confirmation", and user information field 2 may include "AID = 2000" and/or "feedback indicating sleep existence confirmation" type", user information field 3 may include "AID = 3000" and/or "feedback type indicating sleep presence confirmation", and user information field 4 may include "AID = 4000" and/or "Feedback type indicating sleep existence confirmation" may be included. That is, the user information field is "check the state (eg, sleep state) of the STA MLD (eg, STA) having the AID" or "the link in which the STA MLD (eg, the STA) with the AID operates. status (eg, busy state) check" may be indicated. Also, the user information field may include information indicating the number of links allocated to each AID.

Referring back to FIG. 11 , the STA(s) may receive an NFRP presence confirmation frame from the AP, and may check information included in the NFRP presence confirmation frame. The STA(s) may confirm the location of the frequency tone allocated to them based on information included in the user information field of the NFRP presence confirmation frame. For example, the number of frequency tones supported by the STA MLD with "AID = 1000" may be 4, the number of frequency tones supported by the STA MLD with "AID = 2000" may be 3, and "AID = 2000" = 3000", the number of frequency tones supported by the STA MLD may be 5. In this case, frequency tones #1 to #4 may be used by the STA MLD having "AID = 1000", and frequency tones #5 to #7 may be used by the STA MLD having "AID = 2000", Tones #8 to #12 may be used by the STA MLD with "AID = 3000".

"If the AID included in the NFRP presence confirmation frame is the same as the AID of the STA(s), and the NFRP presence confirmation frame requests sleep presence confirmation", the STA(s) may check the operation state or link state, and the operation An NFR frame including information indicating a state or a link state may be transmitted to the AP. For example, "when the operating state of the STA is in the awake state" or "when the link in which the STA operates is in the idle state", the STA may transmit an NFR frame to the AP. If "the operating state of the STA is the sleep state" or "the link in which the STA operates is the busy state", the STA may not transmit the NFR frame to the AP. The STA may transmit an NFR frame (eg, per-tone STF) using a frequency tone indicated by the NFRP presence confirmation frame. The STA may inform the AP of “the existence of the STA, the operational state of the STA and/or the availability of the link” by transmitting the NFR frame.

The AP may receive an NFR frame (eg, per-tone STF) from the STA(s). The AP may identify the STA(s) that have transmitted the per-tone STF based on the position of the frequency tone in which the per-tone STF is received, and may determine that the link in which the STA(s) operates is available. . That is, the AP may determine that the link in which the STA(s) transmitting the per-tone STF operates is in an idle state. Also, the AP may determine that the operating state of the corresponding STA(s) is the awake state. The AP may transmit a data frame (eg, BU) to the STA(s) identified by the per-tone STF. Data frames may be transmitted using available link(s). The STA(s) may receive data from the AP.

The methods according to the present invention may be implemented in the form of program instructions that can be executed by various computer means and recorded in a computer-readable medium. The computer-readable medium may include program instructions, data files, data structures, etc. alone or in combination. The program instructions recorded on the computer-readable medium may be specially designed and configured for the present invention, or may be known and available to those skilled in the art of computer software.

Examples of computer-readable media include hardware devices specially configured to store and carry out program instructions, such as ROM, RAM, flash memory, and the like. Examples of program instructions include not only machine language codes such as those generated by a compiler, but also high-level language codes that can be executed by a computer using an interpreter or the like. The hardware device described above may be configured to operate as at least one software module to perform the operations of the present invention, and vice versa.

Although it has been described with reference to the above embodiments, it will be understood by those skilled in the art that various modifications and changes can be made to the present invention without departing from the spirit and scope of the present invention as set forth in the claims below. will be able

Claims (20)

1. A method of operating an access point (AP) in a communication system, comprising:

   transmitting a first frame to discover a station (STA);

   receiving, from one or more STAs, a second frame indicating that the STA exists in response to the first frame; and

   A method of operating an AP, comprising transmitting a third frame including resource allocation information to the one or more STAs.
2. The method according to claim 1,

   The first frame includes information requesting to confirm the presence of the STA, and the first frame is transmitted through a multi-link.
3. The method according to claim 1,

   The second frame includes a preamble and a short training field (STF), the STF is set in units of frequency tones, and the first STF of a first STA among the one or more STAs is a frequency tone #p, a second STF of a second STA among the one or more STAs is received on a frequency tone #p, and k and p are different natural numbers.
4. The method according to claim 1,

   A frequency band in which the first frame and the second frame are transmitted includes a plurality of frequency tones, and when the communication system supports multiple links, at least two frequency tones from among the plurality of frequency tones are selected from each of the multiple links. Set for, the operating method of the AP.
5. The method according to claim 1,

   If the second frame is not received within a preset time from the transmission time of the first frame, it is determined that the STA does not exist.
6. The method according to claim 1,

   How the AP operates,

   The method further comprises performing a connection procedure with the one or more STAs based on the resource allocation information included in the third frame,

   The third frame further includes an identifier of each of the one or more STAs performing the connection procedure.
7. 7. The method of claim 6,

   The step of performing the connection procedure is,

   The method of operating an AP, further comprising receiving a probe request frame from the one or more STAs.
8. 7. The method of claim 6,

   The step of performing the connection procedure is,

   The method of operating an AP, further comprising transmitting a beacon frame or a non-solicited probe response frame.
9. 7. The method of claim 6,

   The step of performing the connection procedure is,

   and transmitting a beacon frame or a non-requested probe response frame including the system information when the second frame includes an STF requesting system information.
10. The method according to claim 1,

    How the AP operates,

    The method further comprises receiving a trigger frame requesting to perform the discovery procedure of the STA from the master AP,

    The first frame is transmitted when the trigger frame is received, and the AP operates as a relay AP.
11. A method of operating a station (STA) in a communication system, comprising:

    receiving a first frame including information requesting to confirm the presence of the STA from an access point (AP);

    transmitting, to the AP, a second frame indicating that the STA exists in response to the first frame; and

    Receiving a third frame including resource allocation information from the AP, the operating method of the STA.
12. 12. The method of claim 11,

    The second frame includes a preamble and a short training field (STF), the STF is transmitted using a frequency tone, and the frequency tone is set for a link in which the STA operates. how it works.
13. 12. The method of claim 11,

    The method of operation of the STA,

    The method further comprises performing a connection procedure with the AP based on the resource allocation information included in the third frame,

    The third frame further includes an identifier of the STA performing the connection procedure.
14. 14. The method of claim 13,

    The step of performing the connection procedure is,

    The method of operating an STA, further comprising: transmitting a probe request frame to the AP using the resource indicated by the resource allocation information.
15. 14. The method of claim 13,

    The step of performing the connection procedure is,

    The method of operating an STA, further comprising: receiving a beacon frame or an unsolicited probe response frame from the AP.
16. 14. The method of claim 13,

    The step of performing the connection procedure is,

    When the second frame includes an STF requesting system information, receiving a beacon frame or a non-requested probe response frame including the system information from the AP.
17. As an access point (AP) in a communication system,

    processor;

    a memory in electronic communication with the processor; and

    including instructions stored in the memory;

    When the instructions are executed by the processor, the instructions cause the AP to:

    To discover a STA (station), transmit a first frame including information requesting confirmation of the presence of the STA through multiple links;

    receiving, from one or more STAs, a second frame indicating that the STA exists in response to the first frame; And

    and cause transmitting a third frame including resource allocation information to the one or more STAs.
18. 18. The method of claim 17,

    The second frame includes a preamble and a short training field (STF), the STF is set in units of frequency tones, and the first STF of a first STA among the one or more STAs is a frequency tone #p, wherein a second STF of a second STA among the one or more STAs is received on frequency tone #p, wherein k and p are different natural numbers.
19. 18. The method of claim 17,

    The commands allow the AP to

    and performing an association procedure with the one or more STAs based on the resource allocation information included in the third frame,

    The third frame further includes an identifier of each of the one or more STAs performing the connection procedure.
20. 20. The method of claim 19,

    When performing the connection procedure, the commands are the AP,

    the AP being executed to cause performing an “operation of receiving a probe request frame from the one or more STAs” or “an operation of transmitting a beacon frame or an unsolicited probe response frame”.

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