Bandwidth extension in multi-AP cooperation in wireless LAN system

Abstract

The present disclosure relates to bandwidth extension in multi-AP cooperation in a wireless LAN system. According to embodiments of the present disclosure, a method performed by a first AP in a wireless LAN system comprises the steps of: receiving, from a second AP, information about an available bandwidth of the second AP; transmitting, to the second AP, information about an available bandwidth of the first AP, wherein the available bandwidth of the first AP is greater than the available bandwidth of the second AP; receiving, from the second AP, a transmission opportunity (TXOP) sharing frame including information about an allocation interval within a period of a TXOP obtained for the available bandwidth of the second AP; and on the basis of at least one subchannel outside of the available bandwidth of the second AP being in an idle state within the available bandwidth of the first AP, transmitting a frame in the allocation interval through an extended bandwidth including the at least one subchannel and the available bandwidth of the second AP for which the TXOP is obtained.

Description

Bandwidth expansion through multi-AP cooperation in wireless LAN systems

[0001] The present disclosure relates to bandwidth expansion in multi-AP cooperation in a wireless LAN system.

[0002] Next-generation Wi-Fi (e.g., IEEE 802.11be and / or later) aims to support ultra-high reliability when transmitting signals to STAs. To this end, various technologies are being considered to support high throughput, low latency, and extended range. For example, since APs participating in multi-AP cooperation belong to different BSSs, the BSS operating channel widths (or available bandwidths) may differ. In this case, since transmission efficiency based on multi-AP cooperation may decrease, bandwidth expansion may be considered.

[0003] The present disclosure provides a method and device for bandwidth expansion in multi-AP cooperation in a wireless LAN system.

[0004] According to an embodiment of the present disclosure, a method performed by a first AP in a wireless LAN system includes the steps of: receiving, from a second AP, information about an available bandwidth of the second AP; transmitting, to the second AP, information about the available bandwidth of the first AP, wherein the available bandwidth of the first AP is greater than the available bandwidth of the second AP; receiving, from the second AP, a TXOP shared frame including information about an allocation interval within a period of a TXOP (transmission opportunity) acquired for the available bandwidth of the second AP; and transmitting, based on an idle state of at least one subchannel other than the available bandwidth of the second AP within the available bandwidth of the first AP, a frame in the allocation interval through an extended bandwidth including the at least one subchannel and the available bandwidth of the second AP from which the TXOP is acquired.

[0005] According to an embodiment of the present disclosure, a method performed by a second AP in a wireless LAN system includes the steps of: transmitting, to a first AP, information about an available bandwidth of the second AP; receiving, from the first AP, information about the available bandwidth of the first AP, wherein the available bandwidth of the first AP is greater than the available bandwidth of the second AP; determining whether at least one subchannel other than the available bandwidth of the second AP within the available bandwidth of the first AP is idle; and, based on the at least one subchannel being idle, transmitting, to the first AP, a TXOP shared frame including information about an allocation interval within a period of a TXOP acquired for the available bandwidth of the second AP, through an extended bandwidth including the at least one subchannel and the available bandwidth of the second AP.

[0006] In various embodiments, devices for implementing the above-described methods are provided.

[0007] The present disclosure may have various advantageous effects.

[0008] For example, through the bandwidth expansion methods proposed in the present disclosure, the DAP can quickly perform frame exchange using the expanded bandwidth during the allocated time.

[0009] The beneficial effects that can be achieved through specific embodiments of the present disclosure are not limited to the beneficial effects listed above. For example, various technical effects may be understood and / or derived from the present disclosure by those skilled in the art. Therefore, the specific effects of the present disclosure are not limited to those explicitly described herein, but may include various effects that can be understood or derived from the technical features of the present disclosure.

[0010] FIG. 1 illustrates an example of a transmitting device and / or a receiving device of the present disclosure.

[0011] Figure 2 is a conceptual diagram showing the structure of a wireless local area network (WLAN).

[0012] Figure 3 is a diagram illustrating a general link setup process.

[0013] Figure 4 illustrates an embodiment of multi-link (ML).

[0014] FIG. 5 illustrates a modified example of a transmitting device and / or a receiving device of the present disclosure.

[0015] FIG. 6 illustrates an example of a PPDU (physical protocol data unit or physical layer (PHY) protocol data unit) transmitted / received by an STA of the present disclosure.

[0016] Figure 7 is a diagram showing the layout of resource units (RUs) used for 20MHz PPDU.

[0017] Figure 8 is a diagram showing the layout of resource units (RUs) used for 40MHz PPDU.

[0018] Figure 9 is a diagram showing the layout of resource units (RUs) used for 80MHz PPDU.

[0019] Figure 10 shows the operation according to UL-MU.

[0020] Figure 11 shows an example of channels used / supported / defined within the 2.4 GHz band.

[0021] Figure 12 illustrates an example of channels used / supported / defined within the 5 GHz band.

[0022] Figure 13 illustrates an example of channels used / supported / defined within the 6 GHz band.

[0023] Figure 14 shows an example of a random backoff procedure.

[0024] Figure 15 illustrates an example of a procedure related to NAV setting.

[0025] Figure 16 shows the trigger frame format.

[0026] Figure 17 shows an example of the user information field format of MU-RTS TXS TF.

[0027] Figure 18 shows an example of a single TXOP-based coordinated time division multiple access (Co-TDMA) operation diagram between cooperating APs.

[0028] Figure 19 shows an example of two TXOP-based coordinated time division multiple access (Co-TDMA) operations between cooperating APs.

[0029] Figure 20 shows an example where the BSS operating channel widths are different between cooperating APs.

[0030] FIG. 21 illustrates an example of a method performed by a first AP for bandwidth expansion in multi-AP cooperation according to an embodiment of the present disclosure.

[0031] FIG. 22 illustrates an example of a method performed by a second AP for bandwidth expansion in multi-AP cooperation according to an embodiment of the present disclosure.

[0032] FIG. 23 illustrates an example of a bandwidth expansion procedure of SAP when backoff is not performed in Co-TDMA according to an embodiment of the present disclosure.

[0033] FIG. 24 illustrates an example of a bandwidth expansion procedure of SAP when performing backoff in Co-TDMA according to an embodiment of the present disclosure.

[0034] FIG. 25 illustrates a first example of a bandwidth expansion procedure of a DAP when backoff is not performed in Co-TDMA according to an embodiment of the present disclosure.

[0035] FIG. 26 illustrates a second example of a bandwidth expansion procedure of a DAP when backoff is not performed in Co-TDMA according to an embodiment of the present disclosure.

[0036] FIG. 27 illustrates an example of a bandwidth expansion procedure of a DAP when performing backoff in Co-TDMA according to an embodiment of the present disclosure.

[0037] FIG. 28 illustrates an example of a bandwidth expansion procedure during MU-RTS TXS TF / CTS frame exchange in Co-TDMA based on two TXOPs according to an embodiment of the present disclosure.

[0038] FIG. 29 illustrates an example of a bandwidth expansion procedure of a DAP during MU-RTS TXS TF / CTS-to-self frame exchange in Co-TDMA based on two TXOPs according to an embodiment of the present disclosure.

[0039] FIG. 30 illustrates an example of a bandwidth expansion procedure of a DAP when performing backoff in Co-TDMA based on two TXOPs according to an embodiment of the present disclosure.

[0040] FIG. 31 illustrates an example of a bandwidth expansion procedure of a DAP when backoff is not performed in Co-TDMA based on two TXOPs according to an embodiment of the present disclosure.

[0041] In this disclosure, “A or B” can mean “only A,” “only B,” or “both A and B.” In other words, “A or B” in this disclosure can be interpreted as “A and / or B.” For example, “A, B or C” in this disclosure can mean “only A,” “only B,” “only C,” or “any combination of A, B, and C.”

[0042] As used herein, a slash ( / ) or a comma can mean "and / or." For example, "A / B" can mean "A and / or B." Accordingly, "A / B" can mean "only A," "only B," or "both A and B." For example, "A, B, C" can mean "A, B, or C."

[0043] In the present disclosure, “at least one of A and B” may mean “only A,” “only B,” or “both A and B.” Additionally, in the present disclosure, the expressions “at least one of A or B” or “at least one of A and / or B” may be interpreted identically to “at least one of A and B.”

[0044] In addition, parentheses used in the present disclosure may mean “for example.” Specifically, when “control information (UHR-Signal field)” is indicated, the “UHR-Signal field” may be suggested as an example of “control information.” In other words, the “control information” of the present disclosure is not limited to the “UHR-Signal field,” and the “UHR-Signal field” may be suggested as an example of “control information.” In addition, even when indicated as “control information (UHR-Signal field),” the “UHR-Signal field” may be suggested as an example of “control information.”

[0045] Additionally, as used herein, “a / an” can mean “at least one” or “one or more.” Additionally, terms ending in “(s)” can mean “at least one” or “one or more.”

[0046] Additionally, the expressions “based on” or “on the basis of” or “according to” used in this disclosure mean “based at least in part on” and do not mean “based solely on.”

[0047] Technical features individually described in one drawing in this disclosure may be implemented individually or simultaneously.

[0048] The following examples of the present disclosure can be applied to various wireless communication systems. For example, the following examples of the present disclosure can be applied to a wireless local area network (WLAN) system. For example, the present disclosure can be applied to the IEEE 802.11a / g / n / ac / ax / be / bn standards. Furthermore, the examples of the present disclosure can be applied to the Ultra High Reliability (UHR) standard or a next-generation wireless LAN standard that enhances IEEE 802.11bn. Furthermore, the examples of the present disclosure can be applied to a mobile communication system. For example, the examples of the present disclosure can be applied to a mobile communication system based on the Long Term Evolution (LTE) standard and its evolution based on the 3rd Generation Partnership Project (3GPP) standard.

[0049] In order to explain the technical features of the present disclosure, technical features to which the present disclosure can be applied are described below.

[0050] FIG. 1 illustrates an example of a transmitting device and / or a receiving device of the present disclosure.

[0051] An example of FIG. 1 can perform various technical features described below. FIG. 1 relates to at least one STA (station). For example, the STA (110, 120) of the present disclosure may also be referred to by various names such as a mobile terminal, a wireless device, a Wireless Transmit / Receive Unit (WTRU), a User Equipment (UE), a Mobile Station (MS), a Mobile Subscriber Unit, or simply a user. The STA (110, 120) of the present disclosure may also be referred to by various names such as a network, a base station, a Node-B, an access point (AP), a repeater, a router, a relay, etc. The STA (110, 120) of the present disclosure may also be referred to by various names such as a receiving apparatus, a transmitting apparatus, a receiving STA, a transmitting STA, a receiving device, a transmitting device, etc.

[0052] For example, STA (110, 120) may perform the role of an AP (access point) or a non-AP role. That is, STA (110, 120) of the present disclosure may perform the functions of an AP and / or a non-AP. In the present disclosure, an AP may also be indicated as an AP STA.

[0053] The STA (110, 120) of the present disclosure can support various communication standards other than the IEEE 802.11 standard. For example, it can support communication standards according to the 3GPP standard (e.g., LTE, LTE-A, 5G NR standard). In addition, the STA of the present disclosure can be implemented in various devices such as a mobile phone, a vehicle, a personal computer, etc. In addition, the STA of the present disclosure can support communication for various communication services such as voice calls, video calls, data communications, and autonomous driving (Self-Driving, Autonomous-Driving).

[0054] In the present disclosure, STA (110, 120) may include a medium access control (MAC) and a physical layer interface for a wireless medium that follow the provisions of the IEEE 802.11 standard.

[0055] Based on the sub-drawing (a) of Fig. 1, STA (110, 120) is described as follows.

[0056] The first STA (110) may include a processor (111), a memory (112), and a transceiver (113). The illustrated processor, memory, and transceiver may each be implemented as separate chips, or at least two blocks / functions may be implemented through a single chip.

[0057] The transceiver (113) of the first STA performs signal transmission and reception operations. Specifically, it can transmit and receive IEEE 802.11 packets (e.g., IEEE 802.11a / b / g / n / ac / ax / be, etc.).

[0058] For example, the first STA (110) can perform the intended operation of the AP. For example, the processor (111) of the AP can receive a signal through the transceiver (113), process the received signal, generate a transmission signal, and perform control for signal transmission. The memory (112) of the AP can store a signal received through the transceiver (113) (i.e., a reception signal) and store a signal to be transmitted through the transceiver (i.e., a transmission signal).

[0059] For example, the second STA (120) can perform the intended operation of a non-AP STA. For example, the transceiver (123) of the non-AP performs signal transmission and reception operations. Specifically, it can transmit and receive IEEE 802.11 packets (e.g., IEEE 802.11a / b / g / n / ac / ax / be, etc.).

[0060] For example, the processor (121) of the Non-AP STA can receive a signal through the transceiver (123), process the received signal, generate a transmission signal, and perform control for signal transmission. The memory (122) of the Non-AP STA can store a signal received through the transceiver (123) (i.e., a reception signal) and store a signal to be transmitted through the transceiver (i.e., a transmission signal).

[0061] For example, in the specification below, the operation of a device indicated as AP 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 AP may be controlled by the processor (111) of the first STA (110), and a related signal may be transmitted or received through a transceiver (113) controlled by the processor (111) of the first STA (110). In addition, control information related to the operation of the AP or a transmission / reception signal of the AP may be stored in the memory (112) of the first STA (110). In addition, when the second STA (110) is an AP, the operation of the device indicated as an AP is controlled by the processor (121) of the second STA (120), and a related signal can be transmitted or received through a transceiver (123) controlled by the processor (121) of the second STA (120). In addition, control information related to the operation of the AP or the transmission / reception signal of the AP can be stored in the memory (122) of the second STA (110).

[0062] For example, in the specification below, the operation of a device indicated as a non-AP (or User-STA) may be performed in the STA (110) or the second STA (120). For example, if the second STA (120) is a non-AP, the operation of the device indicated as a non-AP may be controlled by the processor (121) of the second STA (120), and a related signal may be transmitted or received through a 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 transmission / reception signal of the AP may be stored in the memory (122) of the second STA (120). For example, if the first STA (110) is a non-AP, the operation of a device indicated as a non-AP is controlled by the processor (111) of the first STA (110), and a related signal may be transmitted or received through a transceiver (113) controlled by the processor (111) of the first STA (120). In addition, control information related to the operation of the non-AP or the transmission / reception signal of the AP may be stored in the memory (112) of the first STA (110).

[0063] In the following specification, 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, etc. may refer to the STA (110, 120) of FIG. 1. For example, devices indicated as (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. without specific drawing symbols may also refer to the STA (110, 120) of FIG. 1. For example, in the example below, the operation of various STAs transmitting and receiving signals (e.g., PPPDU) may be performed by the transceiver (113, 123) of FIG. 1. In addition, in the example below, the operation of various STAs generating transmission and reception signals or performing data processing or calculations in advance for transmission and reception signals may be performed by the processor (111, 121) of FIG. 1.For example, an example of an operation for generating a transmission / reception signal or performing data processing or operation in advance for a transmission / reception signal may include 1) an operation for determining / obtaining / configuring / computing / decoding / encoding bit information of a subfield (SIG, STF, LTF, Data) field included in a PPDU, 2) an operation for determining / configuring / obtaining time resources or frequency resources (e.g., subcarrier resources) used for a subfield (SIG, STF, LTF, Data) field included in a PPDU, 3) an operation for determining / configuring / obtaining a specific sequence (e.g., a pilot sequence, an STF / LTF sequence, an extra sequence applied to SIG) used for a subfield (SIG, STF, LTF, Data) field included in a PPDU, 4) a power control operation and / or a power saving operation applied to an STA, 5) an operation related to determining / obtaining / configuring / computing / decoding / encoding an ACK signal, etc. Additionally, in the examples below, various information (e.g., information related to fields / subfields / control fields / parameters / power, etc.) used by various STAs for determining / acquiring / configuring / computing / decoding / encoding transmission / reception signals can be stored in the memory (112, 122) of FIG. 1.

[0064] The device / STA of the sub-drawing (a) of FIG. 1 described above can be modified as in the sub-drawing (b) of FIG. 1. Hereinafter, the STA (110, 120) of the present disclosure will be described based on the sub-drawing (b) of FIG. 1.

[0065] For example, the transceiver (113, 123) illustrated in sub-drawing (b) of FIG. 1 may perform the same function as the transceiver illustrated in sub-drawing (a) of FIG. 1 described above. For example, the processing chip (114, 124) illustrated in sub-drawing (b) of FIG. 1 may include a processor (111, 121) and a memory (112, 122). The processor (111, 121) and the memory (112, 122) illustrated in sub-drawing (b) of FIG. 1 may perform the same function as the processor (111, 121) and the memory (112, 122) illustrated in sub-drawing (a) of FIG. 1 described above.

[0066] The mobile terminal, wireless device, Wireless Transmit / Receive Unit (WTRU), User Equipment (UE), Mobile Station (MS), Mobile Subscriber Unit, user, user STA, network, Base Station, Node-B, Access Point (AP), repeater, router, relay, receiving device, transmitting device, receiving STA, transmitting STA, receiving Device, transmitting Device, receiving Apparatus, and / or transmitting Apparatus described below may refer to the STA (110, 120) illustrated in the sub-drawings (a) / (b) of FIG. 1, or may refer to the processing chip (114, 124) illustrated in the sub-drawing (b) of FIG. 1. That is, the technical feature of the present disclosure may be performed in the STA (110, 120) illustrated in the sub-drawings (a) / (b) of FIG. 1, or may be performed only in the processing chip (114, 124) illustrated in the sub-drawings (b) of FIG. 1. For example, the technical feature that the transmitting STA transmits a control signal may be understood as a technical feature that the control signal generated in the processor (111, 121) illustrated in the sub-drawings (a) / (b) of FIG. 1 is transmitted through the transceiver (113, 123) illustrated in the sub-drawings (a) / (b) of FIG. 1. Alternatively, the technical feature that the transmitting STA transmits a control signal may be understood as a technical feature that the control signal to be transmitted to the transceiver (113, 123) is generated in the processing chip (114, 124) illustrated in the sub-drawings (b) of FIG. 1.

[0067] For example, the technical feature of a receiving STA receiving a control signal can be understood as a technical feature of a control signal being received by a transceiver (113, 123) illustrated in sub-drawing (a) of FIG. 1. Alternatively, the technical feature of a receiving STA receiving a control signal can be understood as a technical feature of a control signal received by a transceiver (113, 123) illustrated in sub-drawing (a) of FIG. 1 being acquired by a processor (111, 121) illustrated in sub-drawing (a) of FIG. 1. Alternatively, the technical feature of a receiving STA receiving a control signal can be understood as a technical feature of a control signal received by a transceiver (113, 123) illustrated in sub-drawing (b) of FIG. 1 being acquired by a processing chip (114, 124) illustrated in sub-drawing (b) of FIG.

[0068] Referring to the sub-drawing (b) of FIG. 1, software code (115, 125) may be included in the memory (112, 122). The software code (115, 125) may include instructions that control the operation of the processor (111, 121). The software code (115, 125) may be included in various programming languages.

[0069] The processor (111, 121) or processing chip (114, 124) illustrated in FIG. 1 may include an application-specific integrated circuit (ASIC), another chipset, a logic circuit, and / or a data processing device. The processor may be an application processor (AP). For example, the processor (111, 121) or processing chip (114, 124) illustrated in FIG. 1 may include at least one of a digital signal processor (DSP), a central processing unit (CPU), a graphics processing unit (GPU), and a modem (modulator and demodulator). For example, the processor (111, 121) or processing chip (114, 124) illustrated in FIG. 1 may be a SNAPDRAGON® series processor manufactured by Qualcomm®, an EXYNOS® series processor manufactured by Samsung®, an A series processor manufactured by Apple®, a HELIO® series processor manufactured by MediaTek®, an ATOM® series processor manufactured by INTEL®, or an enhanced processor thereof.

[0070] In the present disclosure, uplink may mean a link for communication from a non-AP STA to an AP STA, and uplink PPDU / packet / signal, etc. may be transmitted through the uplink. In addition, in the present disclosure, downlink may mean a link for communication from an AP STA to a non-AP STA, and downlink PPDU / packet / signal, etc. may be transmitted through the downlink.

[0071] Figure 2 is a conceptual diagram showing the structure of a wireless local area network (WLAN).

[0072] The upper part of Figure 2 shows the structure of the infrastructure BSS (basic service set) of IEEE (institute of electrical and electronic engineers) 802.11.

[0073] Referring to the top of FIG. 2, the wireless LAN system may include one or more infrastructure BSSs (200, 205) (hereinafter, BSS). The BSSs (200, 205) are a collection of APs and STAs, such as an access point (AP) 225 and a station (STA1, 200-1), that have successfully synchronized and can communicate with each other, and are not a concept that designates a specific area. The BSS (205) may also include one or more STAs (205-1, 205-2) that can be associated with one AP (230).

[0074] A BSS may include at least one STA, an AP (225, 230) providing a distribution service, and a distribution system (DS, 210) connecting multiple APs.

[0075] A distributed system (210) can connect multiple BSSs (200, 205) to implement an extended service set (ESS, 240). An ESS (240) can be used as a term to indicate a network formed by connecting one or more APs through the distributed system (210). APs included in a single ESS (240) can have the same SSID (service set identification).

[0076] The portal (portal, 220) can act as a bridge to connect a wireless LAN network (IEEE 802.11) to another network (e.g., 802.X).

[0077] In a BSS such as the upper part of Fig. 2, a network between APs (225, 230) and a network between APs (225, 230) and STAs (200-1, 205-1, 205-2) can be implemented. However, it may also be possible to establish a network and perform communication between STAs without an AP (225, 230). A network that establishes a network and performs communication between STAs without an AP (225, 230) is defined as an ad-hoc network or an independent basic service set (IBSS).

[0078] The bottom of Figure 2 is a conceptual diagram showing IBSS.

[0079] Referring to the bottom of Fig. 2, the IBSS is a BSS that operates in ad-hoc mode. Since the IBSS does not include an AP, there is no centralized management entity. That is, in the IBSS, the STAs (250-1, 250-2, 250-3, 255-4, 255-5) are managed in a distributed manner. In the IBSS, all STAs (250-1, 250-2, 250-3, 255-4, 255-5) can be mobile STAs, and access to the distributed system is not permitted, forming a self-contained network.

[0080] Figure 3 is a diagram illustrating a general link setup process.

[0081] In step S310, the STA may perform a network discovery operation. This network discovery operation may include scanning by the STA. That is, for the STA to access the network, it must find a network it can join. Before joining a wireless network, the STA must identify compatible networks. The process of identifying networks in a specific area is called scanning. Scanning methods include active scanning and passive scanning.

[0082] Figure 3 illustrates a network discovery operation that includes an active scanning process as an example. In active scanning, an STA performing scanning transmits a probe request frame to discover which APs exist in the vicinity while moving between channels and waits for a response. A responder transmits a probe response frame to the STA that transmitted the probe request frame in response to the probe request frame. Here, the responder may be the STA that last transmitted a beacon frame in the BSS of the channel being scanned. In a BSS, the AP transmits the beacon frame, so the AP becomes the responder. In an IBSS, the STAs within the IBSS take turns transmitting beacon frames, so the responder is not constant. For example, an STA that transmits a probe request frame on channel 1 and receives a probe response frame on channel 1 can store BSS-related information included in the received probe response frame and move to the next channel (e.g., channel 2) to perform scanning (i.e., transmitting and receiving probe requests / responses on channel 2) in the same manner.

[0083] Although not shown in the example of FIG. 3, the scanning operation can also be performed in a passive scanning manner. An STA performing scanning based on passive scanning can wait for a beacon frame while moving between channels. A beacon frame is one of the management frames in IEEE 802.11. It announces the presence of a wireless network and is periodically transmitted so that the scanning STA can find the wireless network and participate in the wireless network. In the BSS, the AP periodically transmits the beacon frame, and in the IBSS, the STAs within the IBSS take turns transmitting the beacon frame. When the scanning STA receives a beacon frame, it stores the information about the BSS included in the beacon frame and moves to another channel, recording the beacon frame information on each channel. An STA that receives a beacon frame can store the BSS-related information included in the received beacon frame, move to the next channel, and perform scanning on the next channel in the same manner.

[0084] An STA that discovers a network can perform an authentication process through step S320. This authentication process may be referred to as the first authentication process to clearly distinguish it from the security setup operation of step S340 described below. The authentication process of S320 may include a process in which the STA transmits an authentication request frame to the AP, and the AP responds by transmitting an authentication response frame to the STA. The authentication frame used for the authentication request / response corresponds to a management frame.

[0085] The authentication frame may include information such as an authentication algorithm number, an authentication transaction sequence number, a status code, a challenge text, a Robust Security Network (RSN), and a Finite Cyclic Group.

[0086] An STA can transmit an authentication request frame to an AP. The AP can determine whether to grant authentication to the STA based on the information contained in the received authentication request frame. The AP can provide the result of the authentication process to the STA via an authentication response frame.

[0087] A successfully authenticated STA may perform an association process based on step S330. The association process includes a process 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 related to various capabilities, such as a beacon listen interval, a service set identifier (SSID), supported rates, supported channels, RSN, mobility domain, supported operating classes, a Traffic Indication Map Broadcast request, and interworking service capabilities. For example, the association response frame may contain information related to various capabilities, status codes, Association ID (AID), supported rates, Enhanced Distributed Channel Access (EDCA) parameter sets, Received Channel Power Indicator (RCPI), Received Signal to Noise Indicator (RSNI), mobility domains, timeout interval (association comeback time), overlapping BSS scan parameters, TIM broadcast response, QoS maps, etc.

[0088] In step S340, the STA may perform a security setup process. The security setup process of step S340 may include, for example, a process of setting up a private key through a four-way handshaking using an Extensible Authentication Protocol over LAN (EAPOL) frame.

[0089] Figure 4 illustrates an example of multi-link (ML).

[0090] As illustrated in FIG. 4, multiple multi-link devices (MLDs) can communicate over a remote link. The MLDs can be categorized into AP MLDs including multiple AP STAs and non-AP MLDs including multiple non-AP STAs. That is, the AP MLD can include affiliated APs (i.e., AP STAs), and the non-AP MLD can include affiliated STAs (i.e., non-AP STAs, or user-STAs).

[0091] A multilink may include a first link and a second link, and different channels / subchannels / frequency resources may be allocated to the first and second links. The first and second multilinks may be identified through a link ID of 4 bits (or other n bits). The first and second links may be configured in the same 2.4 GHz, 5 GHz, or 6 GHz band. Alternatively, the first link and the second link may be configured in different bands.

[0092] The AP MLD of FIG. 4 includes three affiliated APs. In the example of FIG. 4, AP1 may operate in the 2.4 GHz band, AP2 may operate in the 5 GHz band, and AP3 may operate in the 6 GHz band. In the example of FIG. 4, the first link in which AP1 and non-AP1 operate may be defined as a channel / subchannel / frequency resource within the 2.4 GHz band. Furthermore, in the example of FIG. 4, the second link in which AP2 and non-AP2 operate may be defined as a channel / subchannel / frequency resource within the 5 GHz band. Furthermore, in the example of FIG. 4, the third link in which AP3 and non-AP3 operate may be defined as a channel / subchannel / frequency resource within the 6 GHz band.

[0093] In the example of FIG. 4, AP1 may initiate a multi-link setup procedure (ML setup procedure) by transmitting an Association Request frame to non-AP STA1. In the example of FIG. 4, non-AP STA1 may transmit an Association Response frame in response to the Association Request frame. Each AP (e.g., AP1 / 2 / 3) illustrated in FIG. 4 may be identical to the AP illustrated in FIG. 1 and / or FIG. 2, and each non-AP (e.g., non-AP1 / 2 / 3) illustrated in FIG. 4 may be identical to the STA (i.e., user-STA or non-AP STA) illustrated in FIG. 1 and / or FIG. 2.

[0094] The specific features of the present disclosure are not limited to the specific features of FIG. 4. That is, the number of links can be defined in various ways, and multiple links can be defined in various ways within at least one band.

[0095] FIG. 5 illustrates a modified example of a transmitting device and / or a receiving device of the present disclosure.

[0096] The devices (e.g., AP STA, non-AP STA) illustrated in FIGS. 1 to 4 may be modified as illustrated in FIG. 5. The transceiver (530) of FIG. 5 may be identical to the transceivers (113, 123) of FIG. 1. The transceiver (530) of FIG. 5 may include a receiver and a transmitter.

[0097] The processor (510) of FIG. 5 may be identical to the processor (111, 121) of FIG. 1. Alternatively, the processor (510) of FIG. 5 may be identical to the processing chip (114, 124) of FIG. 1.

[0098] The memory (150) of FIG. 5 may be the same as the memory (112, 122) of FIG. 1. Alternatively, the memory (150) of FIG. 5 may be a separate external memory different from the memory (112, 122) of FIG. 1.

[0099] Referring to FIG. 5, a power management module (511) manages power to a processor (510) and / or a transceiver (530). A battery (512) supplies power to the power management module (511). A display (513) outputs results processed by the processor (510). A keypad (514) receives input to be used by the processor (510). The keypad (514) may be displayed on the display (513). A SIM card (515) may be an integrated circuit used to securely store an international mobile subscriber identity (IMSI) and an associated key used to identify and authenticate a subscriber in a mobile phone device, such as a mobile phone or computer.

[0100] Referring to FIG. 5, the speaker (540) can output sound-related results processed by the processor (510). The microphone (541) can receive sound-related input to be used by the processor (510).

[0101] FIG. 6 illustrates an example of a PPDU (physical protocol data unit or physical layer (PHY) protocol data unit) transmitted / received by an STA of the present disclosure.

[0102] The STA (e.g., AP STA, non-AP STA, AP MLD, non-AP MLD) of the present disclosure can transmit and / or receive the PPDU of FIG. 6. The PPDU described in the present disclosure may have, for example, the structure of FIG. 6. In addition, the PPDU described in the present disclosure may be called by various names such as a transmission PPDU, a reception PPDU, a first type PPDU, or an Nth type PPDU, etc. The PPDU described in the present disclosure can be used in a WLAN system defined according to IEEE 802.11bn and / or a next-generation WLAN system that improves upon IEEE 802.11bn.

[0103] The PPDU of FIG. 6 may be related to various PPDU types used in a UHR system. For example, the example of FIG. 6 may be used for at least one of a single-user (SU) mode / type / transmission, a multi-user (MU) mode / type / transmission, and a null data packet (NDP) mode / type / transmission related to channel sounding. For example, if the example of FIG. 6 is related to NDP, the Data field illustrated may be omitted. If the PPDU of FIG. 6 is used for a trigger-based (TB) mode, the UHR-SIG of FIG. 6 may be omitted. In other words, an STA that has received a trigger frame for UL-MU (Uplink-MU) communication may transmit a PPDU with the UHR-SIG omitted in the example of FIG. 6.

[0104] In FIG. 6, L-STF or UHR-LTF may be called a preamble or physical preamble, and may be generated / transmitted / received / acquired / decoded in the physical layer (included in the transmitting / receiving STA).

[0105] Each block illustrated in Fig. 6 may be called a field / subfield / signal, etc. The names of these fields / subfields / signals may be, as illustrated in Fig. 6, L-STF (legacy short training field), L-LTF (legacy long training field), L-SIG (legacy signal), RL-SIG (repeated L-SIG), U-SIG (Universal Signal), UHR-SIG (UHR-signal), etc.

[0106] The subcarrier spacing of the L-STF, L-LTF, L-SIG, RL-SIG, U-SIG, and UHR-SIG fields in FIG. 6 may be set to 312.5 kHz, and the subcarrier spacing of the UHR-STF, UHR-LTF, and Data fields may be set to 78.125 kHz. That is, the tone index (or subcarrier index) of the L-STF, L-LTF, L-SIG, RL-SIG, U-SIG, and UHR-SIG fields may be expressed in units of 312.5 kHz, and the tone index (or subcarrier index) of the UHR-STF, UHR-LTF, and Data fields may be expressed in units of 78.125 kHz.

[0107] In the PPDU of Fig. 6, L-LTF and L-STF may be identical to conventional fields (e.g., non-HT LTF and non-HT STF defined in conventional WLAN standards).

[0108] The L-SIG field of FIG. 6 may include, for example, 24 bits of bit information. For example, the 24 bits of information may include a 4 bit Rate field, a 1 bit Reserved bit, a 12 bit Length field, a 1 bit Parity bit, and a 6 bit Tail bit. For example, the 12 bit Length field may include information about the length or time duration of the PPDU. For example, the value of the 12 bit Length field may be determined based on the type of the PPDU. For example, if the PPDU is a non-HT (non-High Throughput), HT (High Throughput), VHT (Very High Throughput) PPDU, or an EHT (extremely high throughput) PPDU or UHR PPDU, the value of the Length field may be determined as a multiple of 3. For example, if the PPDU is a HE PPDU, the value of the Length field may be determined as "a multiple of 3 + 1" or "a multiple of 3 + 2". In other words, for non-HT, HT, VHT PPDU, EHT PPDU, UHR PPDU, the value of the Length field can be determined as a multiple of 3, and for HE (High-Efficiency) PPDU, the value of the Length field can be determined as "a multiple of 3 + 1" or "a multiple of 3 + 2". In other words, the Length field in an UHR PPDU is set to a value satisfying the condition that the remainder is zero when LENGTH is divided by 3.

[0109] For example, (non-AP and AP) STAs can apply BCC encoding based on a code rate of 1 / 2 to the 24 bits of information in the L-SIG field. Then, the transmitting STA can obtain 48 BCC coded bits. BPSK modulation can be applied to the 48 coded bits to generate 48 BPSK symbols. The transmitting STA can map the 48 BPSK symbols to positions excluding the pilot subcarriers {subcarrier index -21, -7, +7, +21} and the DC subcarrier {subcarrier index 0}. As a result, the 48 BPSK symbols can be mapped to subcarrier indices -26 to -22, -20 to -8, -6 to -1, +1 to +6, +8 to +20, and +22 to +26. The transmitting STA can additionally map the signal {-1, -1, -1, 1} to the subcarrier indices {-28, -27, +27, +28}. The above signal can be used for channel estimation for the frequency domain corresponding to {-28, -27, +27, +28}.

[0110] For example, (non-AP and AP) STA can generate RL-SIG, which is generated in the same manner as L-SIG. BPSK modulation can be applied to RL-SIG. Receiving (non-AP and AP) STA can determine whether the received PPDU is a HE PPDU, EHT PPDU, or UHR PPDU based on the presence of RL-SIG. In other words, if RL-SIG is present, receiving (non-AP and AP) STA can determine whether the received PPDU is one of HE PPDU, EHT PPDU, or UHR PPDU. In other words, if RL-SIG is not present, receiving (non-AP and AP) STA can determine whether the received PPDU is one of non-HT PPDU, HT PPDU, or VHT PPDU. In other words, the RL-SIG field is a repeat of the L-SIG field and is used to differentiate an UHR PPDU from a non-HT PPDU, HT PPDU, and VHT PPDU.

[0111] After the RL-SIG in Fig. 6, a U-SIG (Universal SIG) may be inserted. The U-SIG may be called by various names such as the first SIG field, the first SIG, the first type SIG, the control signal, the control signal field, the first (type) control signal, the common control field, and the common control signal.

[0112] A U-SIG can contain N bits of information and can include information for identifying the type of EHT PPDU. For example, a U-SIG can be formed based on two symbols (e.g., two consecutive OFDM symbols). Each symbol (e.g., an OFDM symbol) for a U-SIG can have a duration of 4 microseconds. Each symbol of a U-SIG can be used to transmit 26 bits of information. For example, each symbol of a U-SIG can be transmitted and received based on 52 data tones and 4 pilot tones.

[0113] For example, A bit information (e.g., 52 uncoded bits) can be transmitted through U-SIG, and the first symbol of U-SIG can transmit the first X bits of information (e.g., 26 uncoded bits) out of the total A bit information, and the second symbol of U-SIG can transmit the remaining Y bits of information (e.g., 26 uncoded bits) out of the total A bit information. For example, the transmitting STA can obtain 26 uncoded bits included in each U-SIG symbol. The transmitting STA can perform convolutional encoding (i.e., BCC encoding) based on a rate of R=1 / 2 to generate 52 coded bits, and perform interleaving on the 52 coded bits. The transmitting STA can perform BPSK modulation on the interleaved 52 coded bits to generate 52 BPSK symbols allocated to each U-SIG symbol. A single U-SIG symbol can be transmitted based on 56 tones (subcarriers) from subcarrier index -28 to subcarrier index +28, excluding DC index 0. The 52 BPSK symbols generated by the transmitting STA can be transmitted based on the remaining tones (subcarriers) excluding the pilot tones -21, -7, +7, and +21.

[0114] For example, A bit information (e.g., 52 uncoded bits) transmitted by U-SIG may include a CRC field (e.g., a 4-bit long field) and a tail field (e.g., a 6-bit long field). The CRC field and the tail field may be transmitted through the 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 excluding the CRC / tail field within the second symbol, 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".

[0115] The A bit information (e.g., 52 uncoded bits) transmitted by the U-SIG (or U-SIG field) can be divided into version-independent bits and version-dependent bits. For example, the size of the version-independent bits can be fixed or variable. For example, the version-independent bits can be assigned only to the first symbol of the U-SIG, or the version-independent bits can be assigned to both the first symbol and the second symbol of the U-SIG. For example, the version-independent bits and the version-dependent bits can be called by various names, such as the first control bit and the second control bit.

[0116] For example, the 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 transmitted and received PPDU. For example, a first value (e.g., a value of 000) of the 3-bit PHY version identifier may indicate that the transmitted and received PPDU is an EHT PPDU. In addition, a second value (e.g., a value of 001) of the 3-bit PHY version identifier may indicate that the transmitted and received PPDU is an UHR PPDU.

[0117] In other words, when the (AP / non-AP) STA transmits an EHT PPDU, it can set the 3-bit PHY version identifier to the first value. In other words, the receiving (AP / non-AP) STA can determine that the received PPDU is an EHT PPDU based on the PHY version identifier having the first value, and can determine that the received PPDU is an UHR PPDU based on the PHY version identifier having the second value.

[0118] For example, the version-independent bits of U-SIG may include a 1-bit UL / DL flag field. The first value of the 1-bit UL / DL flag field relates to UL communication, and the second value of the UL / DL flag field relates to DL communication.

[0119] For example, the version-independent bits of U-SIG may include information about the length of a transmission opportunity (TXOP) and information about the BSS color ID.

[0120] For example, if a UHR PPDU is classified into various types (e.g., a type related to SU transmission (performed based on UL or DL), a type related to DL transmission, a type related to NDP transmission, a type related to DL non-MU-MIMO, a type related to DL MU-MIMO, a type related to Multi-AP operation, a type related to CO-BF (Coordinated beamforming), SR (Spatial Reuse), a type related to C-OFDMA (Coordinated OFDMA), a type related to CO-TDMA (Coordinated TDMA)), information about the type of the EHT PPDU (e.g., 2-bit or 3-bit information) can be included in the version-dependent bits of the U-SIG.

[0121] For example, a U-SIG may include information about 1) a bandwidth field including information about a bandwidth, 2) a field including information about a Modulation and Coding Scheme (MCS) technique applied to the UHR-SIG, 3) an indication field including information about whether a dual subcarrier modulation (DCM) technique is applied to the UHR-SIG, 4) a field including information about the number of symbols used for the UHR-SIG, 5) a field including information about whether the UHR-SIG is generated over the entire band, 6) a field including information about the type of UHR-LTF / STF, and 7) a field indicating the length of the UHR-LTF and the CP length.

[0122] Preamble puncturing may be applied to the PPDU of FIG. 6. Preamble puncturing refers to applying puncturing to a portion of the entire bandwidth of the PPDU (e.g., the secondary 20 MHz band). For example, when an 80 MHz PPDU is transmitted, the STA may apply puncturing to the secondary 20 MHz band within the 80 MHz band, and transmit the PPDU only through the primary 20 MHz band and the secondary 40 MHz band.

[0123] For example, the pattern of preamble puncturing can be preset. For example, when the first puncturing pattern is applied, puncturing can be applied only to the secondary 20 MHz band within the 80 MHz band. For example, when the second puncturing pattern is applied, puncturing can be applied only to one of the two secondary 20 MHz bands included in the secondary 40 MHz band within the 80 MHz band. For example, when the third puncturing pattern is applied, puncturing can be applied only to the secondary 20 MHz band included in the primary 80 MHz band within the 160 MHz band (or 80+80 MHz band). For example, when the fourth puncturing pattern is applied, a primary 40 MHz band included in the primary 80 MHz band within the 160 MHz band (or 80+80 MHz band) may be present, and puncturing may be applied to at least one 20 MHz channel that does not belong to the primary 40 MHz band.

[0124] Information regarding preamble puncturing applied to the PPDU may be included in the U-SIG and / or UHR-SIG. For example, the first field of the U-SIG may include information regarding the contiguous bandwidth of the PPDU, and the second field of the U-SIG may include information regarding preamble puncturing applied to the PPDU.

[0125] For example, U-SIG and UHR-SIG may include information regarding preamble puncturing based on the following method. If the bandwidth of the PPDU exceeds 80 MHz, the U-SIG may be individually configured in units of 80 MHz. For example, if the bandwidth of the PPDU is 160 MHz, the PPDU may include a first U-SIG for the first 80 MHz band and a second U-SIG for the second 80 MHz band. In this case, the first field of the first U-SIG may include information regarding the 160 MHz bandwidth, and the second field of the first U-SIG may include information regarding preamble puncturing applied to the first 80 MHz band (i.e., information regarding the preamble puncturing pattern). Additionally, the first field of the second U-SIG may include information about a 160 MHz bandwidth, and the second field of the second U-SIG may include information about preamble puncturing applied to the second 80 MHz band (i.e., information about a preamble puncturing pattern). Meanwhile, the UHR-SIG consecutive to the first U-SIG may include information about preamble puncturing applied to the second 80 MHz band (i.e., information about a preamble puncturing pattern), and the UHR-SIG consecutive to the second U-SIG may include information about preamble puncturing applied to the first 80 MHz band (i.e., information about a preamble puncturing pattern).

[0126] Additionally or alternatively, U-SIG and UHR-SIG may include information regarding preamble puncturing based on the following methods. U-SIG may include information regarding preamble puncturing for all bands (i.e., information regarding preamble puncturing patterns). That is, UHR-SIG may not include information regarding preamble puncturing, and only U-SIG may include information regarding preamble puncturing (i.e., information regarding preamble puncturing patterns).

[0127] U-SIGs can be configured in 20 MHz units. For example, if an 80 MHz PPDU is configured, U-SIGs can be duplicated. That is, four identical U-SIGs can be included within an 80 MHz PPDU. PPDUs exceeding the 80 MHz bandwidth can contain different U-SIGs.

[0128] The UHR-SIG of FIG. 6 may include control information for a receiving STA. The UHR-SIG may be transmitted via at least one symbol, and each symbol may have a length of 4 us. Information regarding the number of symbols used for the UHR-SIG may be included in the U-SIG.

[0129] UHR-SIG provides additional signals to the U-SIG field to enable STAs to interpret / decode UHR PPDUs. The UHR-SIG field may contain U-SIG overflow bits that are common to all users. The UHR-SIG field also contains resource allocation information, allowing STAs to look up resources used in fields containing data fields / UHR-STF / UHR-LTF (i.e., UHR modulated fields of an UHR PPDU).

[0130] The frequency resources of the UHR-LTF, UHR-STF, and data fields illustrated in FIG. 6 can be determined based on RUs (resource units) defined by multiple subcarriers / tones. That is, the UHR-LTF, UHR-STF, and data fields of the present disclosure can be transmitted / received through RUs (resource units) defined by multiple subcarriers / tones.

[0131] FIG. 7 is a diagram showing the layout of resource units (RUs) used for a 20 MHz PPDU. That is, the UHR-LTF, UHR-STF, and / or data fields included in the 20 MHz PPDU can be transmitted / received through at least one of the various RUs defined in FIG. 7.

[0132] As shown at the top of Fig. 7, 26 units (i.e., units corresponding to 26 tones) can be arranged. Six tones can be used as a guard band in the leftmost band of the 20 MHz band, and five tones can be used as a guard band in the rightmost band of the 20 MHz band. In addition, seven DC tones can be inserted in the center band, i.e., the DC band, and 26 units corresponding to 13 tones can exist on each side of the DC band. In addition, 26 units, 52 units, and 106 units can be allocated to other bands. Each unit can be allocated for a receiving station, i.e., a user.

[0133] Meanwhile, the RU arrangement of FIG. 7 is utilized not only in a situation for multiple users (MUs) but also in a situation for a single user (SU), in which case it is possible to use one 242-unit as shown at the bottom of FIG. 4, in which case three DC tones can be inserted.

[0134] In the example of Fig. 7, RUs of various sizes, such as 26-RU, 52-RU, 106-RU, and 242-RU, are proposed. Since the specific sizes of these RUs can be expanded or increased, the present embodiment is not limited to the specific size of each RU (i.e., the number of corresponding tones). In the present disclosure, N-RU may be represented as N-tone RU, etc. For example, 26-RU may be represented as 26-tone RU.

[0135] Figure 8 is a diagram showing the layout of resource units (RUs) used for 40MHz PPDU.

[0136] As in the example of Fig. 7 where RUs of various sizes were used, the example of Fig. 8 can also use 26-RU, 52-RU, 106-RU, 242-RU, 484-RU, etc. In addition, 5 DC tones can be inserted at the center frequency, 12 tones can be used as a guard band in the leftmost band of the 40 MHz band, and 11 tones can be used as a guard band in the rightmost band of the 40 MHz band.

[0137] Additionally, as illustrated, 484 RUs may be used when used for a single user. Meanwhile, the specific number of RUs may be changed, as in the example of FIG. 7.

[0138] Figure 9 is a diagram illustrating the layout of resource units (RUs) used for an 80MHz PPDU. The layout of the resource units (RUs) used in the present disclosure may vary. For example, the layout of the resource units (RUs) used in the 80MHz band may vary.

[0139] Figure 10 illustrates an operation according to UL-MU. As illustrated, a transmitting STA (e.g., AP) can acquire a TXOP (1025) by performing channel access through contending (i.e., backoff operation) and transmit a trigger frame (1030). That is, the transmitting STA (e.g., AP) can transmit a PPDU including a trigger frame (1030). When a PPDU including a trigger frame is received, a TB (trigger-based) PPDU is transmitted after a delay of SIFS.

[0140] TB PPDUs (1041, 1042) are transmitted at the same time and can be transmitted from multiple STAs (e.g., User STAs) whose AIDs are indicated in the Trigger frame (1030). The ACK frame (1050) for the TB PPDU can be implemented in various forms. For example, the ACK frame (1050) for the TB PPDU can be implemented in the form of a BA (block ACK).

[0141] In FIG. 10, transmission(s) of a Trigger Frame (1030), a TB PPDU (1041, 1042) and / or an ACK frame (1050) may be performed within a TXOP (1025).

[0142] Figure 11 shows an example of channels used / supported / defined within the 2.4 GHz band.

[0143] The 2.4 GHz band may be referred to by other names, such as the first band (band). Furthermore, the 2.4 GHz band may refer to a frequency range in which channels with a center frequency adjacent to 2.4 GHz (e.g., channels with a center frequency between 2.4 and 2.5 GHz) are used / supported / defined.

[0144] The 2.4 GHz band may include multiple 20 MHz channels. The 20 MHz within the 2.4 GHz band may have multiple channel indices (e.g., indices 1 through 14). For example, the center frequency of a 20 MHz channel assigned channel index 1 may be 2.412 GHz, the center frequency of a 20 MHz channel assigned channel index 2 may be 2.417 GHz, and the center frequency of a 20 MHz channel assigned channel index N may be (2.407 + 0.005*N) GHz. The channel indices may be referred to by various names, such as channel numbers. The specific numerical values ​​of the channel indices and center frequencies may change.

[0145] Figure 11 exemplarily illustrates four channels within the 2.4 GHz band. The illustrated first frequency region (1110) to fourth frequency region (1140) may each include one channel. For example, the first frequency region (1110) may include channel 1 (a 20 MHz channel having an index of 1). In this case, the center frequency of channel 1 may be set to 2412 MHz. The second frequency region (1120) may include channel 6. In this case, the center frequency of channel 6 may be set to 2437 MHz. The third frequency region (1130) may include channel 11. In this case, the center frequency of channel 11 may be set to 2462 MHz. The fourth frequency region (1140) may include channel 14. In this case, the center frequency of channel 14 may be set to 2484 MHz.

[0146] Figure 12 illustrates an example of channels used / supported / defined within the 5 GHz band.

[0147] The 5 GHz band may be referred to by other names, such as a second band / band, etc. The 5 GHz band may refer to a frequency range in which channels with center frequencies greater than or equal to 5 GHz and less than 6 GHz (or less than 5.9 GHz) are used / supported / defined. Alternatively, the 5 GHz band may include multiple channels between 4.5 GHz and 5.5 GHz. The specific figures shown in FIG. 12 are subject to change.

[0148] Multiple channels within the 5 GHz band include Unlicensed National Information Infrastructure (UNII)-1, UNII-2, UNII-3, and ISM. UNII-1 may be referred to as UNII Low. UNII-2 may include frequency ranges called UNII Mid and UNII-2Extended. UNII-3 may be referred to as UNII-Upper.

[0149] Within the 5 GHz band, multiple channels can be configured, and the bandwidth of each channel can be variously configured, such as 20 MHz, 40 MHz, 80 MHz, or 160 MHz. For example, the 5170 MHz to 5330 MHz frequency domain / range within UNII-1 and UNII-2 can be divided into eight 20 MHz channels. The 5170 MHz to 5330 MHz frequency domain / range can be divided into four channels through a 40 MHz frequency domain. The 5170 MHz to 5330 MHz frequency domain / range can be divided into two channels through an 80 MHz frequency domain. Alternatively, the 5170 MHz to 5330 MHz frequency domain / range can be divided into one channel through a 160 MHz frequency domain.

[0150] Figure 13 illustrates an example of channels used / supported / defined within the 6 GHz band.

[0151] The 6 GHz band may also be referred to by other names, such as the third band / band. The 6 GHz band may refer to the frequency range in which channels with center frequencies above 5.9 GHz are used / supported / defined. The specific figures shown in Figure 13 are subject to change.

[0152] For example, the 20 MHz channel of FIG. 13 can be defined from 5.940 GHz. Specifically, the leftmost channel among the 20 MHz channels of FIG. 13 can have an index of 1 (or channel index, channel number, etc.), and a center frequency of 5.945 GHz can be assigned. That is, the center frequency of the indexed channel N can be determined as (5.940 + 0.005*N) GHz.

[0153] Accordingly, the indexes (or channel numbers) of the 20 MHz channels of FIG. 13 are 1, 5, 9, 13, 17, 21, 25, 29, 33, 37, 41, 45, 49, 53, 57, 61, 65, 69, 73, 77, 81, 85, 89, 93, 97, 101, 105, 109, 113, 117, 121, 125, 129, 133, 137, 141, 145, 149, 153, 157, 161, 165, 169, 173, 177, 181, 185, 189, 193, It can be 197, 201, 205, 209, 213, 217, 221, 225, 229, 233. Also, according to the (5.940 + 0.005*N) GHz rule mentioned above, the indices of the 40 MHz channels in Fig. 13 can be 3, 11, 19, 27, 35, 43, 51, 59, 67, 75, 83, 91, 99, 107, 115, 123, 131, 139, 147, 155, 163, 171, 179, 187, 195, 203, 211, 219, 227.

[0154] Meanwhile, STAs that have data to transmit can perform CCA (clear channel assessment) to sense the medium for a specific period (e.g., DIFS (distributed coordination function (DCF) inter-frame space)) before transmitting the data. At this time, if the medium is idle, the STA can perform transmission using the medium. However, if the medium is busy, it can be assumed that multiple STAs are already waiting to use the medium, and the STA can transmit data after waiting for a random backoff period in addition to the DIFS. The random backoff period helps avoid collisions because, assuming that there are multiple STAs to transmit data, each STA will have a different backoff period value probabilistically, resulting in different transmission times. Once one STA starts transmitting, other STAs cannot use the medium.

[0155] In a random backoff procedure, when a specific medium changes from busy to idle, multiple STAs begin preparing to transmit data. To minimize collisions, each STA wishing to transmit data selects a random backoff count and waits for the slot time corresponding to the selected counter. The random backoff count is a pseudo-random integer value, and one of the values ​​is uniformly distributed in the range [0 CW]. CW stands for contention window. The CW parameter takes the CWmin value as the initial value, but if transmission fails, the value is doubled. For example, if an ACK response is not received for a transmitted data frame, it can be considered a collision. When the CW value reaches the CWmax value, the CWmax value is maintained until the data transmission is successful, and if the data transmission is successful, the CW value is reset to the CWmin value. At this time, CW, CWmin, and CWmax are set for convenience of implementation and operation. can be expressed as . Meanwhile, when the random backoff procedure starts, the STA selects a random backoff count within the range [0 CW] and continuously monitors the medium while the backoff slot is counting down. If the medium becomes busy during this time, the countdown is stopped, and when the medium becomes idle again, the countdown for the remaining backoff slots is resumed.

[0156] Figure 14 shows an example of a random backoff procedure.

[0157] Referring to Figure 14, when multiple STAs have data to send, STA3 can transmit the data frame immediately because the medium is idle for DIFS, while the remaining STAs wait for the medium to become idle. Since the medium has been idle for a while, multiple STAs will be looking for an opportunity to use the medium. Therefore, each STA selects a random backoff count, and STA 2, which selects the smallest backoff count, can transmit the data frame. After STA2 completes its transmission, the medium becomes idle again, and the STAs resume counting down the backoff interval where they were paused. STA 5, which has the next smallest random backoff count after STA 2 and paused the countdown while the medium was busy, counts down the remaining backoff slots and starts transmitting the data frame, but by chance, the random backoff count value of STA 4 overlaps, which may cause a collision. At this time, since neither STA receives an ACK response after transmitting data, the two STAs double the CW and then select a random backoff count value again.

[0158] Figure 15 illustrates an example of a procedure related to NAV setting.

[0159] Referring to FIG. 15, when a Source (e.g., AP STA / non-AP STA) that wants to transmit data transmits an RTS (request to send) frame to a Destination (e.g., AP STA / non-AP STA) that receives the data, the Destination can notify surrounding terminals that it will receive the data by transmitting a CTS (clear to send) frame. In other words, the Destination designated as a receiver through the RTS frame can transmit a CTS frame. If the Source that transmitted the RTS frame receives the CTS frame, the Source can start transmitting data to the Destination.

[0160] Meanwhile, if an STA other than the Destination designated as the receiver through the RTS frame receives the RTS frame, or if an STA other than the Source that transmitted the RTS frame receives the CTS frame, the STA may set a network allocation vector (NAV). An STA that has set a NAV may not transmit data during the NAV period, thereby avoiding collisions between the STA and the Source / Destination. On the other hand, if the Destination designated as the receiver through the RTS frame receives the RTS frame, or if the Source that transmitted the RTS frame receives the CTS frame, the Source / Destination does not set a NAV.

[0161] If a CTS frame (e.g., PHY-RXSTART.indication primitive) is not received within a certain period from the time when the RTS frame is received (e.g., the time when the MAC receives the PHY-RXEND.indication primitive corresponding to the RTS frame), STAs that have set or updated the NAV through the RTS frame may reset the NAV (e.g., 0). The certain period may be (2*aSIFSTime + CTS_Time + aRxPHYStartDelay + 2*aSlotTime). The CTS_Time may be calculated based on the length of the CTS frame and the data rate indicated by the RTS frame.

[0162] In Fig. 15, for convenience, setting or updating NAV through RTS frame or CTS frame is illustrated, but NAV setting / resetting / updating may also be performed based on the ¡ field (e.g., duration field in MAC header of MAC frame) of various other frames, for example, non-HT PPDU, HT PPDU, VHT PPDU or HE PPDU. For example, if the RA field in the received MAC frame does not match its own address (e.g., MAC address), the STA may set / reset / update NAV based on the value of the duration field in the received MAC frame.

[0163] Non-AP STAs must maintain two NAVs, and APs can maintain two NAVs: an intra-BSS NAV and a basic NAV. The intra-BSS NAV can be updated / set by PPDUs within the BSS. The basic NAV can be updated / set by inter-BSS PPDUs, or PPDUs that cannot be classified as inter-BSS or intra-BSS.

[0164] The MAC frames included in the data field of the PPDU of the present disclosure can be classified into various types. For example, the MAC frames of the present disclosure can be classified into a control frame, a management frame, and a data frame.

[0165] For example, the management frame includes Association Request, Association Response, Reassociation Request, Reassociation Response, Probe Request, Probe Response, Beacon, Disassociation, Authentication, and Deauthentication frames / signals defined in conventional WLAN. For the management frame, the values ​​of the type fields (B3 and B2) of the MAC header are set to 00. In addition, the values ​​of the subtype fields (B7, B6, B5, B4) of the MAC header are as follows: Association Request (0000), Association Response (0001), Reassociation Request (0010), Reassociation Response (0011), Probe Request (0100), Probe Response (0101), Beacon (1000), Disassociation (1010), Authentication (1011), Deauthentication (1100).

[0166] For example, the control frame includes Trigger Beamforming Report Poll, NDP Announcement (NDPA), Control Frame Extension, Control Wrapper, Block Ack Request (BlockAckReq), Block Ack (BlockAck), PS-Poll, RTS, CTS, Ack, and CF-End frames / signals defined in conventional WLAN. For the control frame, the value of the type field (B3 and B2) of the MAC header is set to 01. Additionally, the values ​​of the subtype fields (B7, B6, B5, B4) of the MAC header are as follows: Trigger (0010), Beamforming Report Poll (0100), NDP Announcement (0101), Control Frame Extension (0110), Control Wrapper (0111), BlockAckReq (1000), BlockAck (1001), PS-Poll (1010), RTS (1011), CTS (1100), Ack (1101), CF-End (1110).

[0167] For example, the data frame includes (QoS) Data, (QoS) Null, etc. defined in conventional WLAN. For the data frame, the value of the type field (B3 and B2) of the MAC header is set to 10.

[0168] The type of the MAC frame used in the present disclosure can be identified through the type field / information and the subtype field / information included in the frame control field of the header of the MAC frame (i.e., the MAC header). For example, the “trigger frame” of the present disclosure can mean a MAC frame in which the type bits B3 and B2 bits in the frame control field of the MAC header are set to 01, and the subtype bits B7, B6, B5, and B4 bits in the frame control field are also set to 0010. Various MAC frames described in the present disclosure are inserted / included in the data field of various PPDUs (e.g., HE / VHT / HE / EHT / UHR PPDUs).

[0169] Figure 16 illustrates a trigger frame format. The trigger frame format may also be referred to as the structure of a trigger frame.

[0170] Referring to FIG. 16, a trigger frame may include a frame control field, a duration / ID field, a receiver address (RA) field, a transmitter address (TA) field, a common info field, a user info list field, a padding field, and / or a frame check sequence (FCS) field. Optionally, the trigger frame may further include a special user info field between the common info field and the user info list field. The user info list field may include one or more user info fields. The frame control field, the duration / ID field, the RA field, and the TA field may constitute a MAC header.

[0171] For example, the common information field may include a trigger type subfield. The trigger type subfield value may indicate a trigger frame variant, as shown in Table 1:

[0172] Trigger type subfield valueTrigger frame variant0Basic1Beamforming Report Poll (BFRP)2MU-BAR3MU-RTS4Buffer Status Report Poll (BSRP)5GCR MU-BAR6Bandwidth Query Report Poll (BQRP)7NDP Feedback Report Poll (NFRP)8-15Reserved

[0173] For example, if the value of the trigger type subfield is set to 0, the trigger frame may be a basic trigger frame. For example, if the value of the trigger type subfield is set to 3, the trigger frame may be a MU (multi-user) RTS trigger frame. Meanwhile, according to the EHT (or 802.11be) standard, in order to support peer-to-peer (P2P) transmission to a non-AP STA, an AP may allocate a portion of the time interval within the TXOP acquired by the AP. In order to allocate a portion of the time interval within the TXOP, a TXOP Sharing Mode subfield may be defined within the Common Info Field of the MU-RTS trigger frame. When the value of the TXOP Sharing Mode subfield is non-zero, such an MU-RTS trigger frame may be referred to as an MU-RTS TXOP Sharing (TXS) trigger frame (TF). The values ​​of the TXOP Sharing Mode subfield are described in Table 2 below:

[0174] Triggered TXOP Sharing Mode subfield valueDescription0MU-RTS that does not initiate MU-RTS TXOP sharing procedure.1MU-RTS that initiates MU-RTS TXOP sharing procedure wherein a scheduledSTA can only transmit MPDU(s) addressed to its associated AP.2MU-RTS that initiates MU-RTS TXOP sharing procedure wherein a scheduled STA can transmit MPDU(s) addressed to its associated AP or addressed to another STA.3Reserved.

[0175] For example, if the value of the TXOP shared mode subfield is 1, one or more (non-TB) PPDU transmissions to the AP may be supported. If the value of the TXOP shared mode subfield is 2, not only (non-TB) PPDU transmissions to the AP but also P2P transmissions may be supported. In the present disclosure, the MU-RTS TXS TF may also be briefly referred to as a TXS trigger frame.

[0176] Figure 17 shows an example of the user information field format of MU-RTS TXS TF.

[0177] Referring to FIG. 17, the user information field may include an AID subfield, an RU allocation subfield, an allocation duration subfield, reserved bits, and / or a PS160 subfield.

[0178] The AID subfield may indicate the AID for the corresponding STA. The RU allocation subfield may indicate RU allocation for the corresponding STA.

[0179] The allocation interval subfield can contain 9 bits from B20 to B28 in the MU-RTS TXS TF and can indicate an allocation interval in units of 16us. In this case, the maximum length of the allocation interval that can be indicated by the allocation interval subfield can be 2^9= 8192us.

[0180] The PS160 subfield may indicate the primary 160MHz channel or the second 160MHz channel to which RU or MRU allocation applies.

[0181] Meanwhile, to enable terminals to maintain continuous WLAN connectivity over a wider area, numerous APs are being installed adjacent to each other. However, overlapping BSSs of multiple APs can lead to issues such as radio interference and transmission collisions between APs. To address these issues, various technologies related to coordination between APs in the frequency, time, and spatial domains (e.g., RU selection, joint transmission, nulling) have been proposed. Furthermore, various issues that may arise during inter-AP cooperation need to be addressed.

[0182] In this disclosure, multi-AP operation is proposed. Multi-AP operation may be based on a technique for reducing various interferences, such as inter-symbol interference (ISI), through coordination with neighboring APs (e.g., APs located in overlapping BSSs).

[0183] For example, multi-AP operation can be categorized into multi-AP cooperation schemes (or, cooperative schemes) based on various technologies / types / formats / protocols. For example, the cooperative scheme may include Coordinated TDMA (Co-TDMA), which distinguishes wireless resources allocated to multiple APs based on the time domain. Additionally or alternatively, the cooperative scheme may include Coordinated OFDMA (C-OFDMA), which distinguishes wireless resources allocated to multiple APs based on the frequency domain. Additionally or alternatively, the cooperative scheme may include Coordinated Spatial Reuse (Co-SR), which applies spatial reuse (SR) to at least one AP. Additionally or alternatively, the cooperative scheme may include Coordinated beamforming (Co-BF) / nulling, which transmits by nulling interference generated from neighboring APs (e.g., adjacent APs / STAs, and / or OBSS APs / OBSS STAs). Additionally or alternatively, the cooperative scheme may include AP selection, in which an AP with a good channel condition among neighboring APs (e.g., at least one AP located within a BSS or OBSS and with a good channel condition) transmits. Additionally or alternatively, the cooperative scheme may include Joint Transmission (JTX) or Joint Transmission (JT), in which multiple APs (e.g., multiple APs within the same BSS / OBSS, or multiple APs within different BSS / OBSS) cooperate to perform simultaneous transmission and reception, and JTX / JT may be implemented based on Joint Beamforming or Joint MU-MIMO.

[0184] In this disclosure, “multi-AP (cooperative) operation” may also be referred to as “multi-AP (cooperative) transmission.” Furthermore, “multi-AP (cooperative) operation / transmission” and “multi-AP cooperative scheme (or cooperative scheme)” may be used interchangeably.

[0185] In order for multi-AP cooperation to be achieved between two APs, the two APs must be in a connected / bonded state, and / or a negotiation procedure must be performed in advance to exchange capability information / requirement information between them, and then multi-AP transmission (e.g., Co-TDMA (coordinated time division multiple access), C-OFDMA (coordinated orthogonal frequency division multiple access), Co-SR (coordinated spatial reuse), Co-BF (coordinated beamforming), AP selection, or J-TX (joint transmission)) can be performed based on the obtained information. In other words, in order for multi-AP transmission to be performed smoothly, a negotiation procedure for configuring / managing multi-AP cooperation and / or transmitting based on a specific multi-AP cooperation method must be performed in advance between the above-described SAP and DAP. A multi-AP set can be set up / configured through the negotiation procedure. Therefore, the negotiation procedure may also be referred to as a multi-AP set setup / configuration procedure.

[0186] For successful multi-AP cooperation, a multi-AP selection procedure may be performed to select a DAP with which the SAP wishes to share TXOPs within a multi-AP set established / configured through a negotiation procedure and / or to notify that the TXOPs will be shared. Through the multi-AP selection procedure, the SAP can determine whether a DAP requires TXOP sharing within the acquired TXOPs, and if a specific DAP does not require TXOP sharing, it can decide to share the TXOPs with subsequent / other DAPs. Alternatively, the SAP can simply notify the target DAPs that it intends to share TXOPs during the multi-AP selection procedure, thereby enabling multi-AP cooperation while reducing the overhead caused by the multi-AP selection procedure.

[0187] In a multi-AP selection procedure, a SAP can send a request frame (i.e., a request frame for AP selection) to select a DAP with which to share a TXOP from a set of multi-APs established / configured through a negotiation procedure, and a DAP that receives the request frame can send a response frame (i.e., a response frame for AP selection) to the request frame based on whether TXOP sharing is required. If a response frame is received from a DAP indicating that TXOP sharing is not required, or if no response frame is received from a DAP, the SAP can send a request frame for AP selection to another DAP - i.e., the SAP can perform AP re-selection. Alternatively, the SAP can simply inform the target DAPs that it intends to share a TXOP in the multi-AP selection procedure. For example, the SAP can send an AP selection request frame without soliciting a response frame to the target DAPs with which it wishes to share a TXOP, and the DAP that receives such an AP selection request frame can prepare for the intended TXOP sharing.

[0188] The SAP transmits a frame for TXOP sharing (e.g., TXOP sharing frame / MU-RTS TXS trigger frame) to the selected DAP through a multi-AP selection procedure, and the DAP can exchange frames with non-AP STA(s) connected to the DAP in the time interval (e.g., allocation interval) allocated by the TXOP sharing frame.

[0189] When the triggered TXOP sharing protocol is utilized for multi-AP coordination, transmissions within the BSS of each cooperative AP are divided into time units, so that each cooperative AP can perform frame exchange without affecting other cooperative APs.

[0190] In the present disclosure, "frame exchange (FE)" may include frame transmission and / or reception operations between STAs. The STAs may be APs or non-AP STAs. Here, the frames may include various types of frames (e.g., data frames, control frames, management frames).

[0191] Figure 18 shows an example of a single TXOP-based coordinated time division multiple access (Co-TDMA) operation diagram between cooperating APs.

[0192] For example, Co-TDMA could mean that each cooperating AP exchanges frames without affecting other cooperating APs by separating transmissions within the BSS of each cooperating AP into time units.

[0193] When the triggered TXS protocol is applied to a multi-AP cooperative operation, an AP in the triggered TXS protocol may be an AP that shares a TXOP in the multi-AP cooperative operation, and an STA in the triggered TXS protocol may be an AP that shares a TXOP in the multi-AP cooperative operation. In the present disclosure, an AP that shares a TXOP may be referred to as a SAP (sharing AP), and an AP that receives a TXOP from a SAP may be referred to as a DAP (shared AP). Here, the term SAP does not limit that the entity that shares a TXOP is only an AP STA, and a SAP may also include a non-AP STA that shares a TXOP. In addition, the term DAP does not limit that the entity that shares a TXOP is only an AP STA, and a DAP may also include a non-AP STA that shares a TXOP (or performs transmission and reception with an AP STA that shares a TXOP). Additionally, the frame exchange performed by the DAP with a non-AP STA or SAP belonging to the DAP BSS during the allocated time (i.e., the allocated period for DAP / AP2 within the TXOP indicated by the MU-RTS TXS TF transmitted from the SAP, which is the time allocated in the MU-RTS TXS TF in FIG. 16) may be referred to as a BSS frame exchange (FE) of the DAP. For example, the RTS / CTS frame exchange between the DAP and the non-AP STA followed by data frame transmission and block ACK frame response, UL data frame transmission of non-AP STAs by a trigger frame transmitted from the DAP, and / or data frame transmission of the DAP by a trigger frame transmitted from the SAP may be performed.

[0194] Figure 19 shows an example of two TXOP-based coordinated time division multiple access (Co-TDMA) operations between cooperating APs.

[0195] Referring to FIG. 19, in two TXOP-based Co-TDMA operations, since the TXOP holder changes when TXOP is shared, the DAP and some non-AP STAs within the DAP's BSS can exchange frames with the DAP without being affected by the NAV of the SAP. Specifically, the SAP can include the nominal TXOP interval value in the frames (e.g., control frames, management frames, trigger frames, and / or data frames) transmitted in the multi-AP selection procedure and transmit them to the cooperating AP(s) during the basic TXOP interval. The DAP(s) that are expected to share the TXOP from the SAP within the nominal TXOP interval can identify in advance whether the TXOP is shared based on the notified nominal TXOP interval information. Therefore, the DAP(s) selected by SAP may wait without performing frame exchange until the scheduled TXOP sharing time, perform secondary channel access depending on the capabilities of the DAP(s), and / or enter AP power mode.

[0196] Because APs participating in multi-AP cooperation belong to different BSSs, their BSS operating channel widths (or available bandwidth) may differ. The greater the difference in available bandwidth between two APs, the lower the efficiency of multi-AP cooperation-based Co-TDMA transmission.

[0197] Figure 20 shows an example where the BSS operating channel widths are different between cooperating APs.

[0198] Referring to Figure 20, the available bandwidth of the SAP sharing the TXOP may be 40MHz, while the available bandwidth of the DAP sharing the TXOP may be 80MHz. In other words, the available bandwidth of the DAP sharing the TXOP may be greater than that of the SAP sharing the TXOP. In this case, the performance improvement for (wideband) transmission using the Co-TDMA method may be minimal.

[0199] Accordingly, the present disclosure provides a method / device for bandwidth expansion for a DAP in a Co-TDMA operation in which TXOP sharing is performed within a single TXOP (e.g., a Co-TDMA operation in which TXOP sharing is performed within a single TXOP, a Co-TDMA operation in which TXOP sharing is performed based on two TXOPs). Specifically, a method / device for supporting bandwidth expansion on the SAP side and a method / device for supporting bandwidth expansion on the DAP side are provided.

[0200] Based on the bandwidth expansion method / device provided in the present disclosure, the DAP can quickly perform frame exchange by utilizing the expanded available bandwidth during the time (or allocation period) allocated from the SAP.

[0201] The specific designations / names proposed in this disclosure may be changed and are not limited thereto.

[0202] FIG. 21 illustrates an example of a method performed by a first AP for bandwidth expansion in multi-AP cooperation according to an embodiment of the present disclosure. In FIG. 21, the first AP may be a DAP, and the second AP may be a SAP.

[0203] Referring to FIG. 21, in step S2101, the first AP can receive information about the available bandwidth (or BSS operating channel width) of the second AP from the second AP.

[0204] In step S2103, the first AP may transmit information about the available bandwidth of the first AP to the second AP. The available bandwidth of the first AP may be greater than the available bandwidth of the second AP.

[0205] In step S2105, the first AP may receive a TXOP shared frame (e.g., MU-RTS TXS TF) from the second AP, which includes information about an allocated interval within the period of a TXOP acquired for the available bandwidth of the second AP.

[0206] In step S2107, based on the fact that at least one subchannel other than the available bandwidth of the second AP is idle within the available bandwidth of the first AP, the first AP can transmit a frame in the allocated section through an extended bandwidth that includes at least one subchannel and the available bandwidth of the second AP for which the TXOP was acquired.

[0207] According to various embodiments, before transmitting a TXOP shared frame, a clear channel assessment (CCA) for at least one subchannel may be performed by the second AP. The TXOP shared frame may be received over an extended bandwidth based on whether the result of the CCA is idle.

[0208] According to various embodiments, CCA may be performed during a short interframe space (SIFS) or a priority interframe space (PIFS).

[0209] According to various embodiments, after receiving a TXOP shared frame over the extended bandwidth, the first AP may transmit a response frame (e.g., a CTS frame / CTS-to-self frame) to the TXOP shared frame over the extended bandwidth to the second AP.

[0210] According to various embodiments, the value of the channel bandwidth parameter (e.g., TXVEXTOR parameter CH_BANDWIDTH) of a PPDU containing a TXOP shared frame received by the first AP over the extended bandwidth may be set to be greater than the value of the channel bandwidth parameter of a PPDU containing a frame transmitted by the second AP over the available bandwidth of the second AP prior to the TXOP shared frame.

[0211] According to various embodiments, after receiving a TXOP shared frame, the first AP may perform a clear channel assessment (CCA) on at least one subchannel. Based on the result of the CCA indicating an idle state, the first AP may transmit a frame in the allocated interval using the extended bandwidth.

[0212] According to various embodiments, after receiving a TXOP shared frame, the first AP may transmit a response frame to the TXOP shared frame to the second AP through the available bandwidth of the second AP.

[0213] According to various embodiments, CCA may be performed during a short interframe space (SIFS) after a TXOP shared frame is received, during a period during which a response frame is transmitted, and during a SIFS after the response frame is transmitted.

[0214] According to various embodiments, CCA may be performed during a short interframe space (SIFS) after a response frame is transmitted.

[0215] According to various embodiments, the CCA may be performed during a short interframe space (SIFS) after a TXOP shared frame is received. Based on the idle state of the result of the CCA, the first AP may transmit a response frame to the TXOP shared frame to the second AP via the extended bandwidth.

[0216] According to various embodiments, the value of the channel bandwidth parameter of a physical layer protocol data unit (PPDU) including a frame transmitted by a first AP through an extended bandwidth may be set to be greater than the value of the channel bandwidth parameter of a PPDU including a frame transmitted by a second AP through an available bandwidth of the second AP.

[0217] According to various embodiments, a clear channel assessment (CCA) may be performed for at least one subchannel. A backoff may be performed for the available bandwidth of the second AP.

[0218] According to various embodiments, the first AP may transmit frames in the allocated interval through the extended bandwidth based on whether the result of the CCA and backoff is idle.

[0219] According to various embodiments, CCA and backoff may be performed before a TXOP shared frame is transmitted. The TXOP shared frame may be received over an extended bandwidth based on whether the result of the CCA and backoff is idle.

[0220] According to various embodiments, after transmitting a response frame to a TXOP shared frame through the available bandwidth of the second AP, the first AP may perform CCA and backoff.

[0221] FIG. 22 illustrates an example of a method performed by a second AP for bandwidth expansion in multi-AP cooperation according to an embodiment of the present disclosure. In FIG. 22 , the first AP may be a DAP, and the second AP may be a SAP.

[0222] Referring to FIG. 22, in step S2201, the second AP can transmit information about the available bandwidth of the second AP to the first AP.

[0223] In step S2203, the second AP may receive information about the available bandwidth of the first AP from the first AP. The available bandwidth of the first AP may be greater than the available bandwidth of the second AP.

[0224] In step S2205, the second AP may determine whether at least one subchannel other than the available bandwidth of the second AP is idle within the available bandwidth of the first AP.

[0225] In step S2207, based on at least one subchannel being idle, the second AP can transmit a TXOP shared frame including information about an allocation interval within a period of a TXOP (transmission opportunity) acquired for the available bandwidth of the second AP to the first AP through an extended bandwidth including at least one subchannel and the available bandwidth of the second AP.

[0226] Below, a detailed implementation for bandwidth expansion in multi-AP cooperation is described.

[0227] I. Bandwidth Expansion in Single TXOP-Based Co-TDMA

[0228] A method and device for expanding bandwidth when sharing TXOPs in Co-TDMA operation are provided. The Co-TDMA operation may include a Co-TDMA operation in which TXOP sharing is performed within a single TXOP.

[0229] 1. How to support bandwidth expansion from the SAP perspective

[0230] (1) Without backoff

[0231] The SAP can obtain information about the available bandwidth of the DAP in the multi-AP selection procedure (or polling / announcement, schedule announcement, and / or coordination announcement procedure), and perform CCA (e.g., energy detection (ED), carrier sensing (CS)) on the expandable bandwidth (i.e., the available bandwidth of the DAP) before sharing the TXOP. The SAP performs TXOP sharing by expanding it up to the available bandwidth of the detected idle state when sharing the TXOP, and the DAP that transmits a response frame (e.g., CTS frame) for the corresponding bandwidth can perform FE during the allocated time (or allocation period) through the expanded bandwidth.

[0232] FIG. 23 illustrates an example of a bandwidth expansion procedure of SAP when backoff is not performed in Co-TDMA according to an embodiment of the present disclosure.

[0233] Referring to FIG. 23, a SAP having a BSS operating channel width (or available bandwidth) of 40 MHz can obtain information about the BSS operating channel width (i.e., 80 MHz) of the current DAP during a multi-AP selection procedure for selecting a DAP to be shared with TXOPs (i.e., a procedure for transmitting / receiving multi-AP selection request / response frames in FIG. 23). Based on the information about the BSS operating channel width (or available bandwidth) of the DAP, the SAP can perform CCA for the available bandwidth of the DAP at SIFS / PIFS intervals before the scheduled TXOP sharing is performed. For example, immediately after receiving a multi-AP selection response frame, the SAP can perform CCA for the operating channel width of the DAP excluding the BSS operating channel width of the SAP (i.e., 40 MHz including primary 20 MHz (P20) + secondary 20 MHz (S20)) during the SIFS / PIFS interval. Additionally, while performing individual frame exchanges with STAs within the BSS of the SAP, the SAP may perform CCA on the secondary 40 MHz (S40) channel during SIFS. Finally, if the SAP performs CCA during SIFS / PIFS just before performing the TXOP sharing scheduled by the SAP and determines that the subchannel(s) included in the BSS operating channel width of the DAP are idle, the SAP may transmit the MU-RTS TXS TF (or control frame / trigger frame) transmitted for TXOP sharing over the extended bandwidth (e.g., 80 MHz in FIG. 23).

[0234] At this time, the TXVECTOR parameter CH_BANDWIDTH (e.g., 80 MHz) of the PPDU containing the MU-RTS TXS TF (or control frame / trigger frame) transmitted by the SAP may have a value greater than the TXVECTOR parameter CH_BANDWIDTH (e.g., 40 MHz) of the PPDU previously transmitted within the TXOP acquired by the SAP. For such cases, the following Rule 1) (and / or exceptions) may be defined for TXOP sharing in Co-TDMA:

[0235] Rule 1) A TXOP holder (i.e., SAP) may set the value of the TXVECTOR parameter CH_BANDWIDTH of a non-initial PPDU containing a MU-RTS TXS TF for TXOP sharing in Co-TDMA (e.g., TXS mode = 1, 2, or a new mode that can be defined for multi-AP cooperation) and / or a trigger frame that can be transmitted to support cooperation-based transmission to a DAP that is newly defined for multi-AP cooperation to be greater than the value of the TXVECTOR parameter CH_BANDWIDTH of the previous PPDU transmitted within the same TXOP.

[0236] Therefore, a SAP following the above-mentioned rule 1) can transmit a MU-RTS TXS TF (or control frame / trigger frame) for TXOP sharing based on (or through) a (sub)channel containing an idle sub-channel identified by CCA during SIFS / PIFS for the sub-channel performed before the TXOP sharing point. A DAP receiving a frame for TXOP sharing can transmit a CTS frame (or response frame) based on (or through) the channel width on which the frame was transmitted. The SAP can identify the BSS operating channel width that the DAP will actually use during the allocated time as the channel width containing the CTS frame transmitted as a response.

[0237] Therefore, the DAP can perform frame exchange faster within the allocated time by utilizing the extended available bandwidth (i.e., 80 MHz) rather than using a bandwidth less than or equal to the BSS operating channel width (i.e., 40 MHz) used by the SAP. In this case, the primary channel of the DAP can be considered to be basically included in the BSS operating channel width of the SAP. Alternatively, the primary channels of the DAP and the SAP can be considered to be the same. When the TXOP return procedure is performed from the DAP within the allocated time (i.e., a TXOP return frame is transmitted to instruct the SAP to return the TXOP), the PPDU containing the TXOP return frame can follow at least one of the following options:

[0238] Option 1) The value of the TXVECTOR parameter CH_BANDWIDTH of the PPDU containing the frame that the DAP transmits to the SAP for TXOP return (i.e., the TXOP return frame) must be set to a value equal to the BSS operating channel width of the SAP, and the TXOP return frame must be contained in a non-HT or non-HT duplicate PPDU.

[0239] Option 2) If the value of the TXVECTOR parameter CH_BANDWIDTH of the PPDU containing the frame that the DAP transmits to the SAP for TXOP return (i.e., the TXOP return frame) is set to the BSS operating channel width value of the DAP, the TXOP return frame must be included in a non-HT duplicate PPDU.

[0240] If there is a remaining TXOP interval after the time allocated to the DAP within the TXOP interval, the SAP must perform frame exchange using its existing BSS operating channel width (i.e., 40 MHz including P20 and S20 in FIG. 23).

[0241] (2) When performing backoff (with backoff)

[0242] The SAP may obtain information about the available bandwidth of the DAP during the multi-AP selection procedure (or polling / announcement, schedule announcement, and / or coordination announcement procedure), and perform backoff on the primary channel and CCA on the subchannels together to secure an expandable bandwidth (i.e., the available bandwidth of the DAP) before sharing the TXOP. The SAP performs TXOP sharing by extending the available bandwidth in the idle state, and the DAP that has transmitted a response frame (e.g., a CTS frame) for the corresponding bandwidth can perform FE during the allocated time (or allocation period) through the extended bandwidth.

[0243] FIG. 24 illustrates an example of a bandwidth expansion procedure of SAP when performing backoff in Co-TDMA according to an embodiment of the present disclosure.

[0244] Referring to FIG. 24, a SAP having a BSS operating channel width (or available bandwidth) of 40 MHz can obtain information about the BSS operating channel width (i.e., 80 MHz) of the current DAP in a multi-AP selection procedure (i.e., a procedure of transmitting / receiving a multi-AP selection request / response frame in FIG. 23) for selecting a DAP to be the target of TXOP sharing. Based on the information about the BSS operating channel width (or available bandwidth) of the DAP, before the scheduled TXOP sharing is performed, the SAP performs i) a backoff for the primary channel and ii) a CCA during SIFS / PIFS for the subchannels, and if the subchannel(s) included in the BSS operating channel width of the DAP are determined to be idle, the SAP can transmit the MU-RTS TXS TF (or control frame / trigger frame) transmitted for TXOP sharing through an extended bandwidth (e.g., 80 MHz in FIG. 24).

[0245] At this time, the TXVECTOR parameter CH_BANDWIDTH (e.g., 80 MHz) of the PPDU containing the MU-RTS TXS TF (or control frame / trigger frame) transmitted by the SAP may have a value greater than the TXVECTOR parameter CH_BANDWIDTH (e.g., 40 MHz) of the PPDU previously transmitted within the TXOP acquired by the SAP. In such a case, the above-described rule 1) (and / or exceptions) for TXOP sharing in Co-TDMA may be applied.

[0246] Therefore, a SAP following the above-mentioned rule 1) may transmit a MU-RTS TXS TF (or control frame / trigger frame) for TXOP sharing based on (or through) a (sub)channel containing an idle sub-channel identified by CCA during backoff for the primary channel and SIFS / PIFS for the sub-channel. A DAP receiving a frame for TXOP sharing may transmit a CTS frame (or response frame) based on (or through) the channel width on which the frame was transmitted. The SAP may identify the BSS operating channel width that the DAP will actually use during the allocated time as the channel width containing the CTS frame transmitted as a response.

[0247] Therefore, the DAP can perform frame exchange faster within the allocated time by utilizing the extended available bandwidth (i.e., 80 MHz) rather than using a bandwidth less than or equal to the BSS operating channel width (i.e., 40 MHz) used by the SAP. In this case, the primary channel of the DAP can be considered to be basically included in the BSS operating channel width of the SAP. Alternatively, the primary channels of the DAP and the SAP can be considered to be the same. When the TXOP return procedure is performed from the DAP within the allocated time (i.e., a TXOP return frame is transmitted to instruct the SAP to return the TXOP), the PPDU containing the TXOP return frame can follow at least one of the following options:

[0248] Option 1) The value of the TXVECTOR parameter CH_BANDWIDTH of the PPDU containing the frame that the DAP transmits to the SAP for TXOP return (i.e., the TXOP return frame) must be set to a value equal to the BSS operating channel width of the SAP, and the TXOP return frame must be contained in a non-HT or non-HT duplicate PPDU.

[0249] Option 2) If the value of the TXVECTOR parameter CH_BANDWIDTH of the PPDU containing the frame that the DAP transmits to the SAP for TXOP return (i.e., the TXOP return frame) is set to the BSS operating channel width value of the DAP, the TXOP return frame must be included in a non-HT duplicate PPDU.

[0250] If there is a remaining TXOP interval after the time allocated to the DAP within the TXOP interval, the SAP must perform frame exchange using its existing BSS operating channel width (i.e., 40 MHz including P20 and S20 in FIG. 24).

[0251] 2. Methods for supporting bandwidth expansion on the DAP side

[0252] (1) Without backoff

[0253] The DAP can perform CCA for the scalable bandwidth immediately after receiving the MU-RTS TXS TF (or control frame / trigger frame) in the TXOP sharing procedure. The DAP can perform FE for the allocated time using the bandwidth that includes the extended bandwidth, up to the available bandwidth in the idle state, regardless of the BSS operating channel width of the MU-RTS TXS TF received from the SAP.

[0254] FIG. 25 illustrates a first example of a bandwidth expansion procedure of a DAP when backoff is not performed in Co-TDMA according to an embodiment of the present disclosure.

[0255] Referring to Figure 25, the SAP may have a BSS operating channel width of 40 MHz, and the DAP may have a BSS operating channel width of 80 MHz. The DAP may perform bandwidth expansion according to Option 1) and / or Option 2) below:

[0256] Option 1) A DAP that receives an MU-RTS TXS TF (or control frame / trigger frame) transmitted by a SAP for TXOP sharing can perform CCA for “SIFS + length of CTS frame (or response frame) + SIFS” for the available bandwidth that is not included in the BSS operating channel width of the SAP (e.g., S40 in FIG. 25). This allows the DAP to perform individual FE using the extended bandwidth (e.g., 80 MHz including S40 in FIG. 25) when a subchannel included in the BSS operating channel width of the DAP is determined to be idle.

[0257] Option 2) A DAP that has transmitted a CTS frame (or derived response framea) for an MU-RTS TXS TF (or control frame / trigger frame) transmitted by a SAP for TXOP sharing can perform CCA during the SIFS / PIFS interval for the available bandwidth (e.g., S40 in Fig. 25) that is not included in the BSS operating channel width of the SAP. This allows the DAP to perform individual FE using the extended bandwidth (e.g., 80 MHz including S40 in Fig. 25) when a subchannel included in the BSS operating channel width of the DAP is determined to be idle.

[0258] FIG. 26 illustrates a second example of a bandwidth expansion procedure of a DAP when backoff is not performed in Co-TDMA according to an embodiment of the present disclosure.

[0259] Referring to FIG. 26, after receiving an MU-RTS TXS TF in a TXOP sharing procedure, the DAP may perform CCA during the SIFS / PIFS interval for the extendable bandwidth, and transmit a CTS frame (or a CTS-to-self frame) over the extended bandwidth to acknowledge reception of the MU-RTS TXS TF. Additionally or alternatively, the CTS frame (or the CTS-to-self frame) may be set to a value less than or equal to a value indicated in the Allocation Interval field in the User Information field of the MU-RTS TXS TF for protection purposes. This allows the DAP to perform individual FE using the extended bandwidth (e.g., 80 MHz including S40 in FIG. 26) when a subchannel included in the BSS operating channel width of the DAP is determined to be idle.

[0260] At this time, the TXVECTOR parameter CH_BANDWIDTH (e.g., 80 MHz) of the PPDU containing the individual frame transmitted by the DAP during the allocated time (i.e., allocation interval) may have a value greater than the TXVECTOR parameter CH_BANDWIDTH (e.g., 40 MHz) of the PPDU previously transmitted from the SAP within the TXOP acquired by the SAP (e.g., the PPDU containing the Multi-AP Selection Request frame and / or the MU-RTS TXS TF). For such cases, the following Rule 2) (and / or exceptions) may be defined for TXOP sharing in Co-TDMA:

[0261] Rule 2) The value of the TXVECTOR parameter CH_BANDWIDTH of a non-initial PPDU containing a frame transmitted by a DAP (i.e., TXOP responder) within the time allocated by the SAP in Co-TDMA may be set to be greater than the value of the TXVECTOR parameter CH_BANDWIDTH of the previous PPDU transmitted by the TXOP holder (i.e., SAP) within the same TXOP.

[0262] Therefore, a DAP following Rule 2) described above can perform frame exchange faster within the allocated time by using the extended bandwidth, including the available bandwidth determined to be idle by CCA for the subchannel performed immediately after receiving the MU-RTS TXS TF. At this time, the primary channel of the DAP may be considered to be basically included in the BSS operating channel width of the SAP. Alternatively, the primary channels of the DAP and the SAP may be considered to be the same. If a TXOP return procedure is performed from the DAP within the allocated time (i.e., a TXOP return frame is transmitted to instruct the SAP to return the TXOP), the PPDU containing the TXOP return frame may follow at least one of the following options:

[0263] Option 1) The value of the TXVECTOR parameter CH_BANDWIDTH of the PPDU containing the frame that the DAP transmits to the SAP for TXOP return (i.e., the TXOP return frame) must be set to a value equal to the BSS operating channel width of the SAP, and the TXOP return frame must be contained in a non-HT or non-HT duplicate PPDU.

[0264] Option 2) If the value of the TXVECTOR parameter CH_BANDWIDTH of the PPDU containing the frame that the DAP transmits to the SAP for TXOP return (i.e., the TXOP return frame) is set to the BSS operating channel width value of the DAP, the TXOP return frame must be included in a non-HT duplicate PPDU.

[0265] If there is a remaining TXOP interval after the time allocated to the DAP within the TXOP interval, the SAP must perform frame exchange using its existing BSS operating channel width (i.e., 40 MHz including P20 and S20 in FIGS. 25 and 26).

[0266] (2) When performing backoff (with backoff)

[0267] The DAP may perform backoff on the primary channel and CCA on the subchannels together to secure scalable bandwidth before performing frame exchange in the allocated time following the TXOP sharing procedure. After transmitting a CTS frame (or response frame) for the MU-RTS TXS TF (or control frame / trigger frame) received from the SAP, the DAP may perform FE during the allocated time using a bandwidth that includes the bandwidth extended up to the available idle bandwidth, regardless of the BSS operating channel width of the MU-RTS TXS TF (or control frame / trigger frame).

[0268] FIG. 27 illustrates an example of a bandwidth expansion procedure of a DAP when performing backoff in Co-TDMA according to an embodiment of the present disclosure.

[0269] Referring to Figure 27, the SAP may have a BSS operating channel width of 40 MHz, and the DAP may have a BSS operating channel width of 80 MHz.

[0270] In the TXOP sharing procedure, a DAP that receives an MU-RTS TXS TF (or control frame / trigger frame) and transmits a CTS frame (or response frame) for the MU-RTS TXS TF (or control frame / trigger frame) can perform backoff for the primary channel and PIFS CCA for the subchannel. This allows the DAP to perform individual FE using the extended bandwidth (e.g., 80 MHz including S40 in FIG. 27) when a subchannel included in the BSS operating channel width of the DAP is determined to be idle.

[0271] At this time, the TXVECTOR parameter CH_BANDWIDTH (e.g., 80 MHz) of the PPDU containing the individual frame transmitted by the DAP may have a value greater than the TXVECTOR parameter CH_BANDWIDTH (e.g., 40 MHz) of the PPDU previously transmitted from the SAP within the TXOP acquired by the SAP (e.g., the PPDU containing the Multi-AP Selection Request frame and / or the MU-RTS TXS TF). In such a case, the Rule 2) (and / or exceptions) described above for TXOP sharing in Co-TDMA may be applied.

[0272] Therefore, a DAP following Rule 2) described above can perform frame exchange faster within the allocated time by using the extended bandwidth, including the available bandwidth determined as idle by CCA during the backoff for the primary channel and the SIFS / PIFS for the subchannel. At this time, the primary channel of the DAP can be considered to be basically included in the BSS operating channel width of the SAP. Alternatively, the primary channels of the DAP and the SAP can be considered to be the same. If a TXOP return procedure is performed from the DAP within the allocated time (i.e., a TXOP return frame is transmitted to instruct the SAP to return the TXOP), the PPDU containing the TXOP return frame can follow at least one of the following options:

[0273] Option 1) The value of the TXVECTOR parameter CH_BANDWIDTH of the PPDU containing the frame that the DAP transmits to the SAP for TXOP return (i.e., the TXOP return frame) must be set to a value equal to the BSS operating channel width of the SAP, and the TXOP return frame must be contained in a non-HT or non-HT duplicate PPDU.

[0274] Option 2) If the value of the TXVECTOR parameter CH_BANDWIDTH of the PPDU containing the frame that the DAP transmits to the SAP for TXOP return (i.e., the TXOP return frame) is set to the BSS operating channel width value of the DAP, the TXOP return frame must be included in a non-HT duplicate PPDU.

[0275] If there is a remaining TXOP interval after the time allocated to the DAP within the TXOP interval, the SAP must perform frame exchange using its existing BSS operating channel width (i.e., 40 MHz including P20 and S20 in FIG. 27).

[0276] II. Bandwidth Expansion in Co-TDMA Based on Two TXOPs

[0277] A method and device for expanding bandwidth when sharing TXOPs in Co-TDMA operation are provided. The Co-TDMA operation may include a Co-TDMA operation based on two TXOPs whose TXOP holders change when TXOP sharing is performed.

[0278] 1. Method for supporting bandwidth expansion when exchanging MU-RTS TXS TF / CTS frames

[0279] A DAP can perform CCA for the scalable bandwidth immediately after receiving an MU-RTS TXS TF in the TXOP sharing procedure or immediately after transmitting a CTS frame in response to an MU-RTS TXS TF. As a TXOP holder for the allocated time (e.g., allocated time in Fig. 28), the DAP can perform FE using the extended bandwidth up to the available idle bandwidth, regardless of the BSS operating channel width of the SAP.

[0280] FIG. 28 illustrates an example of a bandwidth expansion procedure during MU-RTS TXS TF / CTS frame exchange in Co-TDMA based on two TXOPs according to an embodiment of the present disclosure.

[0281] Referring to Fig. 28, the SAP may have a BSS operating channel width of 40 MHz, and the DAP may have a BSS operating channel width of 80 MHz. The DAP, which has received the MU-RTS TXS TF transmitted by the SAP for TXOP sharing, may perform CCA for the available bandwidth (e.g., S40 in Fig. 28) that is not included in the BSS operating channel width of the SAP.

[0282] At this time, the CCA start point and CCA interval can be as in option 1) and / or option 2) below:

[0283] Option 1) DAP can identify / occupy an idle channel by performing CCA during the interval of “SIFS + PPDU length of CTS frame + SIFS” from the time of receiving MU-RTS TXS TF from SAP until the allocated time starts.

[0284] Option 2) DAP can identify / occupy idle channels by performing CCA during SIFS interval immediately after transmitting CTS frame for MU-RTS TXS TF transmitted from SAP.

[0285] If a subchannel included in the BSS operating channel width of the DAP is determined to be idle based on a CCA method such as Option 1) and / or Option 2), the DAP can perform individual FE using the extended bandwidth (e.g., 80 MHz including S40 in FIG. 28).

[0286] At this time, since the DAP performs FE as a TXOP holder, the value of the TXVECTOR parameter CH_BANDWIDTH of the PPDU containing the frame transmitted by the DAP may not be less than or equal to the TXVECTOR parameter CH_BANDWIDTH value of the PPDU transmitted within the TXOP acquired by the SAP.

[0287] Therefore, the DAP can perform frame exchange faster within the allocated time by using the expanded bandwidth, including the available bandwidth that is idle due to CCA for the subchannel performed in the TXOP sharing procedure. At this time, the primary channel of the DAP can be considered to be basically included within the BSS operating channel width of the SAP. If the TXOP return procedure is performed from the DAP within the allocated time (i.e., the DAP transmits a TXOP return frame for TXOP return to the SAP), the PPDU containing the TXOP return frame can follow at least one of the following options:

[0288] Option 1) The value of the TXVECTOR parameter CH_BANDWIDTH of the PPDU containing the frame that the DAP transmits to the SAP for TXOP return (i.e., the TXOP return frame) must be set to a value equal to the BSS operating channel width of the SAP, and the TXOP return frame must be contained in a non-HT or non-HT duplicate PPDU.

[0289] Option 2) If the value of the TXVECTOR parameter CH_BANDWIDTH of the PPDU containing the frame that the DAP transmits to the SAP for TXOP return (i.e., the TXOP return frame) is set to the BSS operating channel width value of the DAP, the TXOP return frame must be included in a non-HT duplicate PPDU.

[0290] If there is a remaining TXOP interval after the time allocated to the DAP within the TXOP interval, the SAP must perform frame exchange using its existing BSS operating channel width (i.e., 40 MHz including P20 and S20 in FIG. 28).

[0291] 2. Method for supporting bandwidth expansion during MU-RTS TXS TF / CTS-to-self frame exchange

[0292] (1) Method for expanding the bandwidth of DAP

[0293] The DAP can perform CCA for the expandable bandwidth immediately after receiving the MU-RTS TXS TF in the TXOP sharing procedure, and can perform the response and / or NAV setup process (sequence) for the MU-RTS TXS TF by transmitting a CTS-to-Self frame through the expanded bandwidth. The DAP can perform FE through the expanded bandwidth up to the available bandwidth that is idle, regardless of the BSS operating channel width of the SAP, as a TXOP holder during the allocated time (e.g., the allocated time in FIG. 29).

[0294] FIG. 29 illustrates an example of a bandwidth expansion procedure of a DAP during MU-RTS TXS TF / CTS-to-self frame exchange in Co-TDMA based on two TXOPs according to an embodiment of the present disclosure.

[0295] Referring to Fig. 29, the SAP may have a BSS operating channel width of 40 MHz, and the DAP may have a BSS operating channel width of 80 MHz. The DAP, which has received the MU-RTS TXS TF transmitted by the SAP for TXOP sharing, may perform CCA during SIFS for the available bandwidth (e.g., S40 in Fig. 29) that is not included in the BSS operating channel width of the SAP.

[0296] This allows the DAP to perform individual FEs using the extended bandwidth (e.g., 80 MHz including S40 in FIG. 29) when a subchannel included in the BSS operating channel width of the DAP is determined to be idle.

[0297] At this time, since the DAP performs FE as a TXOP holder, the value of the TXVECTOR parameter CH_BANDWIDTH of the PPDU containing the frame transmitted by the DAP may not be less than or equal to the TXVECTOR parameter CH_BANDWIDTH value of the PPDU transmitted within the TXOP acquired by the SAP.

[0298] Therefore, the DAP can perform frame exchange faster within the allocated time by using the expanded bandwidth, including the available bandwidth that is idle due to CCA for the subchannel performed in the TXOP sharing procedure. In addition, the process for acknowledging the reception of the MU-RTS TXS TF and setting the NAV can be performed by transmitting a CTS-to-self frame. At this time, the primary channel of the DAP can be considered to be basically included within the BSS operating channel width of the SAP, and the CTS-to-self frame can be included in a non-HT duplicate PPDU. If the TXOP return procedure is performed from the DAP within the allocated time (i.e., if the DAP transmits a TXOP return frame for TXOP return to the SAP), the PPDU containing the TXOP return frame can follow at least one of the following options:

[0299] Option 1) The value of the TXVECTOR parameter CH_BANDWIDTH of the PPDU containing the frame that the DAP transmits to the SAP for TXOP return (i.e., the TXOP return frame) must be set to a value equal to the BSS operating channel width of the SAP, and the TXOP return frame must be contained in a non-HT or non-HT duplicate PPDU.

[0300] Option 2) If the value of the TXVECTOR parameter CH_BANDWIDTH of the PPDU containing the frame that the DAP transmits to the SAP for TXOP return (i.e., the TXOP return frame) is set to the BSS operating channel width value of the DAP, the TXOP return frame must be included in a non-HT duplicate PPDU.

[0301] If there is a remaining TXOP interval after the time allocated to the DAP within the TXOP interval, the SAP must perform frame exchange using its existing BSS operating channel width (i.e., 40 MHz including P20 and S20 in FIG. 29).

[0302] (2) SAP bandwidth expansion method

[0303] In the multi-AP selection procedure, the SAP can identify the available bandwidth of the DAP and perform TXOP sharing by either option 1) performing backoff for the primary channel and CCA for the subchannels to occupy the expandable bandwidth (i.e., the available bandwidth of the DAP / the BSS operating channel width of the DAP) before sharing the TXOP, or option 2) performing CCA only for the subchannels. When sharing the TXOP, the SAP transmits MU-RTS TXS TF over the expanded bandwidth up to the idle available bandwidth, and the DAP that transmitted the CTS-to-Self frame for that bandwidth can perform FE during the allocated time over that expanded bandwidth.

[0304] FIG. 30 illustrates an example of a bandwidth expansion procedure of a DAP when performing backoff in Co-TDMA based on two TXOPs according to an embodiment of the present disclosure.

[0305] Referring to FIG. 30, a SAP having a BSS operating channel width of 40 MHz can obtain information about the BSS operating channel width of the current DAP (i.e., 80 MHz) during a multi-AP selection procedure for selecting a DAP to be shared with TXOPs (i.e., a process of transmitting / receiving multi-AP selection request / response frames in FIG. 30). Based on the information about the BSS operating channel width of the DAP, the SAP can perform backoff on the primary channel before the scheduled TXOP sharing, perform CCA during SIFS / PIFS on the subchannel, and if a subchannel included in the BSS operating channel width of the DAP is idle, the SAP can transmit TXOP sharing through MU-RTS TXS TF over an extended bandwidth (i.e., 80 MHz in FIG. 30).

[0306] FIG. 31 illustrates an example of a bandwidth expansion procedure of a DAP when backoff is not performed in Co-TDMA based on two TXOPs according to an embodiment of the present disclosure.

[0307] Referring to FIG. 31, similarly to the case of performing a backoff, the SAP can obtain information about the BSS operating bandwidth of the current DAP during the multi-AP selection procedure. Based on the information about the BSS operating bandwidth of the DAP, the SAP can perform CCA for the available bandwidth of the DAP (i.e., the BSS operating bandwidth of the DAP) at SIFS / PIFS intervals before the scheduled TXOP sharing is performed. For example, the SAP can perform CCA for the BSS operating channel width of the DAP excluding the BSS operating channel width of the SAP (i.e., 40 MHz including P20+S20) during the SIFS / PIFS interval immediately after receiving the multi-AP selection response frame. In addition, the SAP can perform CCA for the S40 channel during SIFS even when performing individual frame exchanges with STAs within the BSS of the SAP. Finally, if a CCA is performed during SIFS / PIFS before the scheduled TXOP sharing by the SAP determines that a subchannel included in the BSS operating channel width of the DAP is idle, the SAP can transmit the MU-RTS TXS TF over the extended bandwidth (i.e., 80 MHz in FIG. 31) for TXOP sharing.

[0308] A DAP that receives an MU-RTS TXS TF transmitted via the method illustrated in Option 1) (or FIG. 30) and / or Option 2) (or FIG. 31) may transmit a CTS-to-Self frame via the channel width in which the MU-RTS TXS TF was transmitted. The SAP may identify the BSS operating channel width that the DAP will actually use during the allocated time as the channel width that includes the CTS-to-Self frame transmitted in response.

[0309] At this time, since the DAP performs FE as a TXOP holder, the value of the TXVECTOR parameter CH_BANDWIDTH of the PPDU containing the frame transmitted by the DAP may not be less than or equal to the TXVECTOR parameter CH_BANDWIDTH value of the PPDU transmitted within the TXOP acquired by the SAP.

[0310] Therefore, the DAP can perform frame exchange faster within the allocated time by utilizing the bandwidth including the extended bandwidth, rather than using a bandwidth less than or equal to the BSS operating channel width used by the SAP. In addition, the process for acknowledging the reception of the MU-RTS TXS TF and setting the NAV can be performed by transmitting a CTS-to-self frame. At this time, the primary channel of the DAP can be considered to be basically included within the BSS operating channel width of the SAP, and the CTS-to-self frame can be included in a non-HT duplicate PPDU. If the TXOP return procedure is performed from the DAP within the allocated time (i.e., if the DAP transmits a TXOP return frame for TXOP return to the SAP), the PPDU including the TXOP return frame can follow at least one of the following options:

[0311] Option 1) The value of the TXVECTOR parameter CH_BANDWIDTH of the PPDU containing the frame that the DAP transmits to the SAP for TXOP return (i.e., the TXOP return frame) must be set to a value equal to the BSS operating channel width of the SAP, and the TXOP return frame must be contained in a non-HT or non-HT duplicate PPDU.

[0312] Option 2) If the value of the TXVECTOR parameter CH_BANDWIDTH of the PPDU containing the frame that the DAP transmits to the SAP for TXOP return (i.e., the TXOP return frame) is set to the BSS operating channel width value of the DAP, the TXOP return frame must be included in a non-HT duplicate PPDU.

[0313] If there is a remaining TXOP interval after the time allocated to the DAP within the TXOP interval, the SAP must perform frame exchange using its existing BSS operating channel width (i.e., 40 MHz including P20 and S20 in FIGS. 30 and 31).

[0314] The present disclosure provides a bandwidth expansion method / device for a DAP that shares TXOPs from an SAP in Co-TDMA operation. Specifically, a method / device for an SAP to support bandwidth expansion and a method / device for a DAP to support bandwidth expansion are provided.

[0315] According to the bandwidth expansion method by SAP, SAP can perform CCA at SIFS / PIFS intervals to evaluate whether a subchannel is idle and share TXOPs based on the results of this evaluation. Alternatively, SAP can perform backoff on the primary channel and CCA on the subchannels simultaneously to evaluate whether the channels are idle and share TXOPs based on the results of this evaluation.

[0316] According to the bandwidth expansion method by DAP, DAP can evaluate whether the subchannel is idle during the TXOP sharing process, or perform backoff for the primary channel and CCA for the subchannel together before the allocated time to evaluate whether the channels are idle.

[0317] Through the bandwidth expansion methods proposed in this disclosure, the DAP can quickly perform frame exchange using the expanded bandwidth during the allocated time.

[0318] In addition, the present disclosure provides a bandwidth expansion method / device for a DAP that shares a TXOP from a SAP in two TXOP-based Co-TDMA operations in which the TXOP holder changes. For example, a bandwidth expansion method / device based on the exchange of MU-RTS TXS TF / CTS frames and a bandwidth expansion method / device based on the exchange of MU-RTS TXS TF / CTS-to-Self frames are provided.

[0319] According to a bandwidth expansion method based on the exchange of MU-RTS TXS TF / CTS frames, the DAP can perform CCA immediately after receiving the MU-RTS TXS TF or immediately after transmitting the CTS frame, and can determine whether the subchannel is idle based on the CCA.

[0320] According to the bandwidth expansion method based on the exchange of MU-RTS TXS TF / CTS-to-Self frames, the DAP or the SAP can perform CCA as described above.

[0321] Through the bandwidth expansion methods proposed in this disclosure, the DAP can quickly perform frame exchange using the expanded bandwidth during the allocated time.

[0322] The technical features of the present disclosure described above can be applied to various devices and methods. For example, the technical features of the present disclosure described above can be performed / supported by the devices of FIG. 1 and / or FIG. 5. For example, the technical features of the present disclosure described above can be applied only to a portion of FIG. 1 and / or FIG. 5. For example, the technical features of the present disclosure described above can be implemented based on the processing chip (114, 124) of FIG. 1, or based on the processor (111, 121) and memory (112, 122) of FIG. 1, or based on the processor (510) and memory (520) of FIG. 5.

[0323] For example, the processor (121) and / or the processing chip (124) of FIG. 1 may be configured to execute instructions stored in the memory (122) to perform operations performed by the first AP in the present disclosure. The operations include: receiving, from a second AP, information about an available bandwidth of the second AP; transmitting, to the second AP, information about an available bandwidth of the first AP, wherein the available bandwidth of the first AP is greater than the available bandwidth of the second AP; receiving, from the second AP, a TXOP shared frame including information about an allocated interval within a period of a TXOP (transmission opportunity) acquired for the available bandwidth of the second AP; and transmitting, based on an idle state of at least one subchannel other than the available bandwidth of the second AP within the available bandwidth of the first AP, a frame in the allocated interval through an extended bandwidth including the at least one subchannel and the available bandwidth of the second AP from which the TXOP was acquired.

[0324] For example, the processor (111), the processing chip (114) of FIG. 1, and / or the processor (510) of FIG. 5 may be configured to execute instructions stored in the memory (112, 520) to perform operations performed by the second AP in the present disclosure. The operations include: transmitting information about an available bandwidth of the second AP to the first AP; receiving information about an available bandwidth of the first AP from the second AP, wherein the available bandwidth of the first AP is greater than the available bandwidth of the second AP; determining whether at least one subchannel other than the available bandwidth of the second AP is idle within the available bandwidth of the first AP; And based on the at least one subchannel being idle, the second AP transmits a TXOP shared frame including information about an allocation interval within a period of a TXOP (transmission opportunity) acquired for the available bandwidth of the second AP to the first AP through an extended bandwidth including the at least one subchannel and the available bandwidth of the second AP.

[0325] The technical features of the present disclosure can be implemented based on a computer-readable medium (CRM). For example, the CRM proposed by the present disclosure is at least one computer-readable recording medium containing instructions that are executed by at least one processor.

[0326] For example, the CRM may be the memory (122) of FIG. 1 and / or a separate external memory / storage medium / disk. The CRM may store commands that perform operations performed by the first AP in the present disclosure based on being executed by a processor (e.g., the processor (121) and / or the processing chip (124) of FIG. 1). The operations include: receiving, from a second AP, information about an available bandwidth of the second AP; transmitting, to the second AP, information about an available bandwidth of the first AP, wherein the available bandwidth of the first AP is greater than the available bandwidth of the second AP; receiving, from the second AP, a TXOP shared frame including information about an allocated interval within a period of a TXOP (transmission opportunity) acquired for the available bandwidth of the second AP; And, based on at least one subchannel other than the available bandwidth of the second AP being idle within the available bandwidth of the first AP, an operation of transmitting a frame in the allocated interval through an extended bandwidth including the at least one subchannel and the available bandwidth of the second AP from which the TXOP is acquired.

[0327] For example, the CRM may be the memory (112) of FIG. 1, the memory (520) of FIG. 5, and / or a separate external memory / storage medium / disk. The CRM may store commands that perform operations performed by the second AP in the present disclosure based on being executed by a processor (e.g., the processor (111), the processing chip (114) of FIG. 1, and / or the processor (510) of FIG. 5). The operations include: transmitting, to the first AP, information about the available bandwidth of the second AP; receiving, by the second AP, information about the available bandwidth of the first AP from the first AP, wherein the available bandwidth of the first AP is greater than the available bandwidth of the second AP; determining, by the second AP, whether at least one subchannel other than the available bandwidth of the second AP is idle within the available bandwidth of the first AP; And based on the at least one subchannel being idle, the second AP transmits a TXOP shared frame including information about an allocation interval within a period of a TXOP (transmission opportunity) acquired for the available bandwidth of the second AP to the first AP through an extended bandwidth including the at least one subchannel and the available bandwidth of the second AP.

[0328] The technical features of the present disclosure described above are applicable to various applications and business models. For example, the technical features described above can be applied to wireless communication in devices that support artificial intelligence (AI).

[0329] Artificial intelligence (AI) is the study of artificial intelligence or the methodologies for creating it, while machine learning (ML) defines various problems in the field of AI and studies the methodologies for solving them. Machine learning is also defined as an algorithm that improves performance on a task through consistent experience.

[0330] An artificial neural network (ANN) is a model used in machine learning. It can refer to a model with problem-solving capabilities, consisting of artificial neurons (nodes) formed by the connection of synapses to form a network. An ANN can be defined by the connection patterns between neurons in different layers, the learning process that updates model parameters, and the activation function that generates output values.

[0331] An artificial neural network may include an input layer, an output layer, and optionally one or more hidden layers. Each layer contains one or more neurons, and the artificial neural network may include synapses connecting neurons. In an artificial neural network, each neuron can output a function value of an activation function based on input signals, weights, and biases received through the synapses.

[0332] Model parameters are parameters determined through learning, including synaptic connection weights and neuron biases. Hyperparameters are parameters that must be set before learning in machine learning algorithms, including the learning rate, number of iterations, mini-batch size, and initialization function.

[0333] The goal of artificial neural network training can be seen as determining model parameters that minimize a loss function. The loss function can be used as an indicator for determining optimal model parameters during the artificial neural network training process.

[0334] Machine learning can be classified into supervised learning, unsupervised learning, and reinforcement learning depending on the learning method.

[0335] Supervised learning refers to a method for training an artificial neural network when given labels for the training data. The labels can refer to the correct answer (or output value) that the artificial neural network must infer when the training data is input to the artificial neural network. Unsupervised learning can refer to a method for training an artificial neural network when the training data is not given labels. Reinforcement learning can refer to a learning method in which an agent defined within a given environment is trained to select actions or action sequences that maximize the cumulative reward in each state.

[0336] Machine learning implemented with a deep neural network (DNN) containing multiple hidden layers among artificial neural networks is also called deep learning, and deep learning is a subset of machine learning. Hereinafter, the term "machine learning" is used to encompass deep learning.

[0337] Additionally, the above-described technical features can be applied to wireless communication of robots.

[0338] A robot can be defined as a machine that automatically performs or operates a given task based on its own capabilities. Specifically, a robot capable of perceiving its environment, making independent judgments, and performing actions can be called an intelligent robot.

[0339] Robots can be categorized into industrial, medical, household, and military applications based on their intended use or field. Robots are equipped with actuators or motors, enabling them to perform various physical actions, such as moving robot joints. Furthermore, mobile robots incorporate wheels, brakes, and propellers into their actuators, enabling them to move on the ground or fly in the air.

[0340] Additionally, the above-described technical features can be applied to devices that support extended reality.

[0341] Extended reality is a general term for virtual reality (VR), augmented reality (AR), and mixed reality (MR). VR technology presents real-world objects and backgrounds as CG images only, AR technology presents virtual CG images over images of real objects, and MR technology is a computer graphics technology that blends and combines virtual objects with the real world.

[0342] MR technology is similar to AR in that it presents both real and virtual objects simultaneously. However, while AR uses virtual objects to complement real objects, MR uses virtual and real objects on an equal footing.

[0343] XR technology can be applied to HMD (Head-Mount Display), HUD (Head-Up Display), mobile phones, tablet PCs, laptops, desktops, TVs, digital signage, etc., and devices to which XR technology is applied can be called XR devices.

[0344] The present disclosure may have various advantageous effects.

[0345] For example, through the bandwidth expansion methods proposed in the present disclosure, the DAP can quickly perform frame exchange using the expanded bandwidth during the allocated time.

[0346] The beneficial effects that can be achieved through specific embodiments of the present disclosure are not limited to the beneficial effects listed above. For example, various technical effects may be understood and / or derived from the present disclosure by those skilled in the art. Therefore, the specific effects of the present disclosure are not limited to those explicitly described herein, but may include various effects that can be understood or derived from the technical features of the present disclosure.

[0347] The claims set forth in this disclosure may be combined in various ways. For example, the technical features of the method claims of this disclosure may be combined and implemented as a device, and the technical features of the device claims of this disclosure may be combined and implemented as a method. Furthermore, the technical features of the method claims of this disclosure and the technical features of the device claims of this disclosure may be combined and implemented as a device, and the technical features of the method claims of this disclosure and the technical features of the device claims of this disclosure may be combined and implemented as a method.

Claims

1. A step in which a first AP (access point) receives information about the available bandwidth of a second AP from a second AP; A step in which the first AP transmits information about the available bandwidth of the first AP to the second AP; The available bandwidth of the first AP is greater than the available bandwidth of the second AP; A step in which the first AP receives a TXOP shared frame from the second AP, the TXOP shared frame including information about an allocated interval within a period of a TXOP (transmission opportunity) acquired for the available bandwidth of the second AP; and A method comprising: a step of the first AP transmitting a frame in the allocated interval over an extended bandwidth that includes the at least one subchannel and the available bandwidth of the second AP from which the TXOP is acquired, based on at least one subchannel other than the available bandwidth of the second AP being idle within the available bandwidth of the first AP.

2. In claim 1, before the TXOP shared frame is transmitted, a CCA (clear channel assessment) is performed for at least one subchannel, The above TXOP shared frame is received through the extended bandwidth based on the result of the CCA being idle.

3. In claim 2, the CCA is performed during a short interframe space (SIFS) or a priority interframe space (PIFS).

4. A method according to claim 2, further comprising the step of: after receiving the TXOP shared frame through the extended bandwidth, the first AP transmits a response frame to the TXOP shared frame through the extended bandwidth to the second AP.

5. A method according to claim 2, wherein a value of a channel bandwidth parameter of a PPDU (physical layer protocol data unit) including the TXOP shared frame received by the first AP through the extended bandwidth is set to be greater than a value of a channel bandwidth parameter of a PPDU including a frame transmitted by the second AP through the available bandwidth of the second AP prior to the TXOP shared frame.

6. In claim 1, after receiving the TXOP shared frame, the first AP further includes a step of performing CCA (clear channel assessment) for at least one subchannel, A method wherein the step of transmitting a frame in the allocated interval through the extended bandwidth comprises the step of transmitting a frame in the allocated interval through the extended bandwidth based on the result of the CCA being in an idle state.

7. A method according to claim 6, further comprising the step of: after receiving the TXOP shared frame, the first AP transmits a response frame to the TXOP shared frame to the second AP through the available bandwidth of the second AP.

8. A method according to claim 7, wherein the CCA is performed during a short interframe space (SIFS) after the TXOP shared frame is received, a period during which the response frame is transmitted, and a SIFS after the response frame is transmitted.

9. A method according to claim 7, wherein the CCA is performed during a short interframe space (SIFS) after the response frame is transmitted.

10. In claim 6, the CCA is performed during a short interframe space (SIFS) after the TXOP shared frame is received, A method further comprising the step of: the first AP transmitting a response frame for the TXOP shared frame to the second AP through the extended bandwidth based on the result of the CCA being idle.

11. A method according to claim 1, wherein the value of the channel bandwidth parameter of a physical layer protocol data unit (PPDU) including a frame transmitted by the first AP through the extended bandwidth is set to be greater than the value of the channel bandwidth parameter of a PPDU including a frame transmitted by the second AP through the available bandwidth of the second AP.

12. In claim 1, CCA (clear channel assessment) is performed for at least one subchannel, A method in which a backoff is performed for the available bandwidth of the second AP.

13. A method according to claim 12, wherein the step of transmitting a frame in the allocated interval through the extended bandwidth comprises the step of transmitting a frame in the allocated interval through the extended bandwidth based on the result of the CCA and the backoff being an idle state.

14. In claim 12, the CCA and the backoff are performed before the TXOP shared frame is transmitted, A method in which the above TXOP shared frame is received through the extended bandwidth based on the result of the CCA and the backoff being idle.

15. A method according to claim 12, further comprising the step of performing the CCA and the backoff after transmitting a response frame to the TXOP shared frame through the available bandwidth of the second AP.

16. At the first AP (access point), Transmitter and receiver; memory; and At least one processor functionally coupled with the transceiver and the memory, The above memory stores instructions for performing operations based on being executed by the at least one processor, the operations being: An action of receiving information about the available bandwidth of the second AP from the second AP; An operation of transmitting information about the available bandwidth of the first AP to the second AP; The available bandwidth of the first AP is greater than the available bandwidth of the second AP; An operation of receiving a TXOP shared frame including information about an allocated interval within a period of a TXOP (transmission opportunity) acquired for the available bandwidth of the second AP from the second AP; and A first AP including an operation of transmitting a frame in the allocated interval over an extended bandwidth that includes the at least one subchannel and the available bandwidth of the second AP from which the TXOP is acquired, based on at least one subchannel other than the available bandwidth of the second AP being idle within the available bandwidth of the first AP.

17. In the device, at least one processor; and comprising at least one memory functionally coupled with at least one processor; The at least one memory stores instructions that perform operations based on being executed by the at least one processor, the operations comprising: An action of receiving information about the available bandwidth of the second AP from the second AP; An operation of transmitting information about the available bandwidth of the first AP to the second AP; The available bandwidth of the first AP is greater than the available bandwidth of the second AP; An operation of receiving a TXOP shared frame including information about an allocated interval within a period of a TXOP (transmission opportunity) acquired for the available bandwidth of the second AP from the second AP; and A device comprising an operation of transmitting a frame in the allocated interval through an extended bandwidth that includes the at least one subchannel and the available bandwidth of the second AP from which the TXOP is acquired, based on at least one subchannel other than the available bandwidth of the second AP being idle within the available bandwidth of the first AP.

18. A non-transitory computer readable medium (CRM) storing program code implementing instructions that perform operations based on being executed by at least one processor, said operations comprising: An action of receiving information about the available bandwidth of the second AP from the second AP; An operation of transmitting information about the available bandwidth of the first AP to the second AP; The available bandwidth of the first AP is greater than the available bandwidth of the second AP; An operation of receiving a TXOP shared frame including information about an allocated interval within a period of a TXOP (transmission opportunity) acquired for the available bandwidth of the second AP from the second AP; and A CRM comprising an operation of transmitting a frame in the allocated interval over an extended bandwidth that includes the at least one subchannel and the available bandwidth of the second AP from which the TXOP is acquired, based on at least one subchannel other than the available bandwidth of the second AP being idle within the available bandwidth of the first AP.

19. A step in which a second AP (access point) transmits information about the available bandwidth of the second AP to the first AP; A step in which the second AP receives information about the available bandwidth of the first AP from the first AP; The available bandwidth of the first AP is greater than the available bandwidth of the second AP; The step of the second AP determining whether at least one subchannel other than the available bandwidth of the second AP is idle within the available bandwidth of the first AP; and A method comprising: based on the at least one subchannel being idle, the second AP transmitting, to the first AP, a TXOP shared frame including information about an allocation interval within a period of a TXOP acquired for the available bandwidth of the second AP, over an extended bandwidth including the at least one subchannel and the available bandwidth of the second AP.

20. At the second AP (access point), Transmitter and receiver; memory; and At least one processor functionally coupled with the transceiver and the memory, The above memory stores instructions for performing operations based on being executed by the at least one processor, the operations being: An operation of transmitting information about the available bandwidth of the second AP to the first AP; An operation in which the second AP receives information about the available bandwidth of the first AP from the first AP; The available bandwidth of the first AP is greater than the available bandwidth of the second AP; The operation of the second AP determining whether at least one subchannel other than the available bandwidth of the second AP is idle within the available bandwidth of the first AP; and A second AP including an operation of transmitting, to the first AP, a TXOP shared frame including information about an allocation interval within a period of a TXOP acquired for the available bandwidth of the second AP, through an extended bandwidth including the at least one subchannel and the available bandwidth of the second AP, based on the at least one subchannel being idle.

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