TXOP sharing for multiple aps in wireless LAN system

Abstract

The present disclosure relates to TXOP sharing for multiple APs in a wireless LAN system. According to an embodiment of the present disclosure, a method performed by a first AP configured to operate in a wireless LAN system comprises the steps of: performing a negotiation procedure for multi-AP cooperation with one or more other APs; on the basis of the negotiation procedure, acquiring a configuration for a set of APs for the multi-AP cooperation; transmitting a selection request frame for requesting selection of one or more APs for transmission opportunity (TXOP) sharing in the set of APs to the one or more APs, wherein a duration field of the selection request frame includes information on an initial time duration until a TXOP sharing frame is transmitted to a second AP, to which the TXOP sharing frame is first transmitted, among the one or more APs; from at least one AP including the second AP among the one or more APs, receiving a selection response frame for the selection request frame; and when the initial time duration expires, transmitting the TXOP sharing frame to the second AP.

Description

TXOP sharing for multiple APs in a wireless LAN system

[0001] The present disclosure relates to TXOP sharing for multiple APs 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 achieve this, various technologies are being considered to support high throughput, low latency, and extended range. For example, TXOP sharing could be implemented between multiple APs.

[0003] The present disclosure provides a method and device for sharing TXOPs for multiple APs in a wireless LAN system.

[0004] According to an embodiment of the present disclosure, a method performed by a first AP configured to operate in a wireless LAN system includes the steps of: performing a negotiation procedure for multi-AP cooperation with one or more other APs; acquiring a configuration for a set of APs for the multi-AP cooperation based on the negotiation procedure; transmitting a selection request frame to one or more APs for requesting selection of one or more APs for sharing a transmission opportunity (TXOP) from the set of APs, wherein a duration field of the selection request frame includes information about an initial time duration until the TXOP shared frame is transmitted to a second AP from among the one or more APs to which the TXOP shared frame is first transmitted; receiving a selection response frame for the selection request frame from at least one AP including the second AP from among the one or more APs; and transmitting the TXOP shared frame to the second AP upon expiration of the initial time duration.

[0005] According to an embodiment of the present disclosure, a method performed by a second AP configured to operate in a wireless LAN system includes the steps of: performing a negotiation procedure for multi-AP cooperation with one or more other APs; acquiring a configuration for a set of APs for the multi-AP cooperation based on the negotiation procedure; receiving a selection request frame from a first AP in the set of APs to request selection of one or more APs for transmission opportunity (TXOP) sharing in the set of APs, wherein a duration field of the selection request frame includes information about an initial time duration until the TXOP sharing frame is transmitted to the second AP to which the TXOP sharing frame is first transmitted among the one or more APs; transmitting a selection response frame for the selection request frame to the first AP; and receiving the TXOP sharing frame from the first AP upon expiration of the initial time duration.

[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, based on the TXOP sharing method for multiple APs proposed in the present disclosure, the SAP can perform signaling and / or set a duration field to sequentially perform TXOP sharing to multiple DAPs so as to minimize protection and / or hidden node issues.

[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, and 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 illustrates an example of a procedure related to NAV setting.

[0024] Figure 15 shows the trigger frame format.

[0025] Figure 16 shows an example of operation when the value of the TXOP shared mode subfield is 2.

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

[0027] FIG. 18 illustrates an example of a multi-AP selection procedure according to an embodiment of the present disclosure.

[0028] Figure 19 shows an example of TXOP sharing operation between multiple APs in Co-TDMA.

[0029] FIG. 20 illustrates an example of a method performed by a first AP for TXOP sharing for multiple APs according to an embodiment of the present disclosure.

[0030] FIG. 21 illustrates an example of a method performed by a second AP for TXOP sharing for multiple APs according to an embodiment of the present disclosure.

[0031] FIG. 22 illustrates an example of setting a duration field of a trigger frame transmitted in a multi-AP selection procedure according to an embodiment of the present disclosure.

[0032] FIG. 23 illustrates an example of setting a duration field of a frame transmitted for TXOP sharing for multiple APs according to an embodiment of the present disclosure.

[0033] FIG. 24 illustrates a first example of a sequence in which all APs participating in multi-AP cooperation respond to an MU-RTS TXS TF according to an embodiment of the present disclosure.

[0034] FIG. 25 illustrates a second example of a sequence in which all APs participating in multi-AP cooperation respond to the MU-RTS TXS TF according to an embodiment of the present disclosure.

[0035] FIG. 26 illustrates a first example of a sequence in which only the target DAP for current TXOP sharing among APs participating in multi-AP cooperation responds to the MU-RTS TXS TF according to an embodiment of the present disclosure.

[0036] FIG. 27 illustrates a second example of a sequence in which only the target DAP for current TXOP sharing among the APs participating in multi-AP cooperation responds to the MU-RTS TXS TF according to an embodiment of the present disclosure.

[0037] FIG. 28 illustrates a first example of a sequence in which only APs selected for TXOP sharing among APs participating in multi-AP cooperation respond to MU-RTS TXS TF according to an embodiment of the present disclosure.

[0038] FIG. 29 illustrates a second example of a sequence in which only APs selected for TXOP sharing among APs participating in multi-AP cooperation respond to the MU-RTS TXS TF according to an embodiment of the present disclosure.

[0039] 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.”

[0040] 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."

[0041] 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.”

[0042] 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.”

[0043] 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.”

[0044] 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.”

[0045] Technical features individually described in one drawing in this disclosure may be implemented individually or simultaneously.

[0046] 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.

[0047] In order to explain the technical features of the present disclosure, technical features to which the present disclosure can be applied are described below.

[0048] FIG. 1 illustrates an example of a transmitting device and / or a receiving device of the present disclosure.

[0049] 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.

[0050] 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.

[0051] 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).

[0052] 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.

[0053] Based on the sub-drawing (a) of Fig. 1, STA (110, 120) is described as follows.

[0054] 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.

[0055] 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.).

[0056] 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).

[0057] 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.).

[0058] 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).

[0059] 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).

[0060] 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).

[0061] 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.

[0062] 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.

[0063] 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.

[0064] 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 a transmitting STA transmits a control signal may be understood as a technical feature that a control signal generated in a processor (111, 121) illustrated in the sub-drawings (a) / (b) of FIG. 1 is transmitted through a transceiver (113, 123) illustrated in the sub-drawings (a) / (b) of FIG. 1. Alternatively, the technical feature that a transmitting STA transmits a control signal may be understood as a technical feature that a control signal to be transmitted to a transceiver (113, 123) is generated in the processing chip (114, 124) illustrated in the sub-drawings (b) of FIG. 1.

[0065] 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.

[0066] 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.

[0067] 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.

[0068] 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.

[0069] Figure 2 is a conceptual diagram showing the structure of a wireless local area network (WLAN).

[0070] 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.

[0071] 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).

[0072] The BSS may include at least one STA, an AP (225, 230) providing a distribution service, and a distribution system (DS, 210) connecting multiple APs.

[0073] 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).

[0074] 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).

[0075] 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).

[0076] The bottom of Figure 2 is a conceptual diagram showing IBSS.

[0077] 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.

[0078] Figure 3 is a diagram illustrating a general link setup process.

[0079] 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.

[0080] 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.

[0081] 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.

[0082] 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.

[0083] 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.

[0084] 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.

[0085] 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.

[0086] 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.

[0087] Figure 4 illustrates an example of a multi-link (ML).

[0088] 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).

[0089] 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.

[0090] 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.

[0091] 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.

[0092] 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.

[0093] FIG. 5 illustrates a modified example of a transmitting device and / or a receiving device of the present disclosure.

[0094] 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.

[0095] 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.

[0096] 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.

[0097] 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.

[0098] 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).

[0099] 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.

[0100] 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.

[0101] 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.

[0102] 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).

[0103] 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.

[0104] 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.

[0105] 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).

[0106] 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.

[0107] 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}.

[0108] 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.

[0109] 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.

[0110] 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.

[0111] 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.

[0112] 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".

[0113] 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.

[0114] 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.

[0115] 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.

[0116] 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.

[0117] 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.

[0118] 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.

[0119] 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.

[0120] 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.

[0121] 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.

[0122] 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.

[0123] 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).

[0124] 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).

[0125] 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.

[0126] 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.

[0127] 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).

[0128] 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.

[0129] 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.

[0130] 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.

[0131] 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.

[0132] 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.

[0133] Figure 8 is a diagram showing the layout of resource units (RUs) used for 40MHz PPDU.

[0134] 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.

[0135] 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.

[0136] 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.

[0137] 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.

[0138] 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).

[0139] 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).

[0140] Figure 11 shows an example of channels used / supported / defined within the 2.4 GHz band.

[0141] 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.

[0142] 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.

[0143] 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.

[0144] Figure 12 illustrates an example of channels used / supported / defined within the 5 GHz band.

[0145] 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.

[0146] 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.

[0147] 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.

[0148] Figure 13 illustrates an example of channels used / supported / defined within the 6 GHz band.

[0149] 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.

[0150] 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.

[0151] 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.

[0152] 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.

[0153] 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.

[0154] Figure 14 illustrates an example of a procedure related to NAV setting.

[0155] Referring to FIG. 14, 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.

[0156] 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.

[0157] 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.

[0158] In Fig. 14, 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 fields of other various frames, such as non-HT PPDU, HT PPDU, VHT PPDU or HE PPDU (e.g., duration field in MAC header of MAC frame). For example, if the RA field in the received MAC frame / RTS frame / CTS 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 / RTS frame / CTS frame.

[0159] 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.

[0160] 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.

[0161] 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).

[0162] 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).

[0163] 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.

[0164] 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).

[0165] Figure 15 illustrates a trigger frame format. The trigger frame format may also be referred to as the structure of a trigger frame.

[0166] Referring to FIG. 15, 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.

[0167] 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:

[0168] 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)8Ranging9-15Reserved

[0169] 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, the 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:

[0170] 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.

[0171] 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.

[0172] Figure 16 shows an example of operation when the value of the TXOP shared mode subfield is 2.

[0173] Referring to FIG. 16, an AP may transmit an MU-RTS TXS TF including allocation (time) interval information (e.g., Time allocated in MU-RTS TXS Trigger Frame) to non-AP STA 1. Non-AP STA 1 may transmit a CTS in response to the MU-RTS TXS TF and perform P2P transmission to non-AP STA 2.

[0174] Figure 17 shows an example of the user information field format of MU-RTS TXS TF.

[0175] 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.

[0176] The AID subfield may indicate the AID for the corresponding STA. The RU allocation subfield may indicate RU allocation for the corresponding STA.

[0177] 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.

[0178] The PS160 subfield may indicate the primary 160MHz channel or the second 160MHz channel to which RU or MRU allocation applies.

[0179] 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.

[0180] 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).

[0181] 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.

[0182] 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.

[0183] When the triggered TXOP sharing protocol is utilized for multi-AP cooperation (e.g., Co-TDMA), 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. In this case, the AP in the triggered TXS protocol may be an AP that shares TXOP in multi-AP cooperation operation, and the STA in the triggered TXS protocol may be an AP that shares TXOP in multi-AP cooperation operation.

[0184] 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 the entity that shares a TXOP to only AP STAs, and a SAP may also include non-AP STAs that share a TXOP. In addition, the term DAP does not limit the entity that shares a TXOP to only AP STAs, and a DAP may also include non-AP STAs that share a TXOP (or transmit and receive with an AP STA that shares a TXOP).

[0185] Additionally, a frame exchange performed by a DAP with a non-AP STA or SAP belonging to the DAP BSS during the allocated time (i.e., the allocated period for the DAP 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) may be referred to as a BSS frame exchange (FE) of the DAP. For example, a data frame transmission and a block ACK frame response following an RTS / CTS frame exchange between the DAP and a non-AP STA, a UL data frame transmission of non-AP STAs by a trigger frame transmitted from the DAP, and / or a data frame transmission of the DAP by a trigger frame transmitted from the SAP may be performed.

[0186] 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).

[0187] 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 cooperation request frames / cooperation response frames containing capability information / requirement information of each AP, 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.

[0188] For successful multi-AP cooperation, a multi-AP selection procedure (or AP selection procedure for multi-AP cooperation) 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 to be performed while reducing the overhead caused by the multi-AP selection procedure.

[0189] FIG. 18 illustrates an example of a multi-AP selection procedure according to an embodiment of the present disclosure.

[0190] Referring to FIG. 18, in a multi-AP selection procedure, a SAP may transmit a request frame (i.e., a request frame for AP selection / selection request frame) to one or more DAPs to select a DAP with which to share a TXOP from a multi-AP set established / configured through a negotiation procedure, and one or more DAP(s) receiving the request frame may transmit a response frame (i.e., a response frame for AP selection / selection response frame) to the request frame based on whether TXOP sharing is required. If a response frame including an indication that TXOP sharing is not required is received from a DAP(s), or if a response frame is not received from a DAP(s), the SAP may transmit a request frame for AP selection to another DAP - i.e., the SAP may perform AP reselection. Alternatively, the SAP may simply inform the target DAP(s) that it intends to share a TXOP in the multi-AP selection procedure. For example, a SAP can send an AP selection request frame that does not solicit a response frame to the target DAP with which it wishes to share a TXOP, and the DAP receiving such an AP selection request frame can prepare an action for the intended TXOP sharing.

[0191] 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.

[0192] In this disclosure, multi-AP selection may be used interchangeably with schedule announcement, coordination announcement, and cooperative polling.

[0193] Figure 19 shows an example of TXOP sharing operation between multiple APs in Co-TDMA.

[0194] Referring to FIG. 19, a SAP can perform TXOP sharing to support Co-TDMA-based transmission to multiple DAPs. An AP that acquires a TXOP and acts as an SAP can transmit a trigger frame (e.g., MU-RTS TF, BSRP TF) for a procedure for selecting DAP(s) that want to support Co-TDMA-based transmission within the acquired TXOP (i.e., multi-AP selection) and / or a procedure for notifying the DAP(s) of a schedule (i.e., schedule notification). The DAP(s) (e.g., DAP 1, DAP2, DAP 3 in FIG. 19) for supporting Co-TDMA-based transmission can transmit a response frame (e.g., CTS frame, Multi-STA BA frame) in response to receiving a trigger frame. Subsequently, the SAP can exchange frames individually with STAs within its BSS, and can transmit MU-RTS TXS TF for TXOP sharing to the target DAP (e.g., DAP1, DAP3 in FIG. 19) at a time indicated by the multi-AP selection and / or schedule announcement procedure (or at a time arbitrarily determined by the SAP).

[0195] Upon receiving the MU-RTS TXS TF and identifying its own BSSID (or MAC address), BSS color, multi-AP group ID and / or multi-AP ID, the target DAP (e.g., DAP1, DAP3 in FIG. 19) transmits a CTS frame as a response and can perform individual frame exchanges during the allocated interval (e.g., interval of T_1 for DAP 1, time of T_3 for DAP 3).

[0196] To effectively perform TXOP sharing among multiple APs in Co-TDMA, protection issues and hidden node problems that may arise when sharing TXOPs among multiple APs must be addressed. Furthermore, detailed signaling and / or duration field settings for TXOP sharing among multiple APs must be defined.

[0197] Accordingly, the present disclosure provides various embodiments for alternatives to issues that may arise when sharing a TXOP among multiple APs in Co-TDMA, and for setting specific frame sequences, signaling and / or duration fields.

[0198] According to various embodiments of the present disclosure, based on a TXOP sharing method for multiple APs in Co-TDMA, a SAP can perform TXOP sharing sequentially to multiple DAPs by signaling and / or setting a duration field to minimize protection and / or hidden node issues.

[0199] The specific designations / names proposed in this disclosure may be changed and are not limited thereto.

[0200] FIG. 20 illustrates an example of a method performed by a first AP for TXOP sharing for multiple APs according to an embodiment of the present disclosure. The first AP may be a SAP.

[0201] Referring to FIG. 20, in step S2001, the first AP can perform a negotiation procedure for multi-AP cooperation with one or more other APs.

[0202] In step S2003, the first AP can obtain settings for a set of APs for multi-AP cooperation based on a negotiation procedure.

[0203] In step S2005, the first AP may transmit a selection request frame to one or more APs to request selection of one or more APs for TXOP sharing (or whether one or more APs participate in TXOP sharing) from a set of APs. The duration field of the selection request frame may include information about an initial time duration until a TXOP sharing frame is transmitted to a second AP among the one or more APs to which the TXOP sharing frame (e.g., MU-RTS TXS TF) is transmitted first.

[0204] In step S2007, the first AP can receive a selection response frame for a selection request frame from at least one AP, including a second AP among one or more APs.

[0205] In step S2009, the first AP may transmit a TXOP shared frame to the second AP upon expiration of the initial time interval.

[0206] According to various embodiments, the user information field for the second AP in the TXOP shared frame may include information about an allocation interval allocated to the second AP. The allocation interval may include an interval in which frame exchange is performed by the second AP.

[0207] According to various embodiments, the duration field of the TXOP shared frame may include at least one of information about a remaining TXOP interval or information about an allocated interval allocated to a second AP. The remaining TXOP interval may be a time interval after the TXOP shared frame is transmitted in the entire TXOP interval.

[0208] According to various embodiments, after transmitting a TXOP shared frame to a second AP, a first AP may transmit a TXOP shared frame to a third AP among one or more APs. In this case, the duration field of the TXOP shared frame transmitted to the second AP may include information regarding the time period until the TXOP shared frame is transmitted to the third AP.

[0209] According to various embodiments, after transmitting a TXOP shared frame to a second AP, a first AP may not transmit a TXOP shared frame to any of the one or more APs. In this case, the duration field of the TXOP shared frame transmitted to the second AP may include information about the remaining TXOP period.

[0210] According to various embodiments, the TXOP shared frame may include information about the second AP. The information about the second AP may include at least one of an address of the second AP, a basic service set (BSS) identifier (ID) of the second AP, a BSS color for the second AP, a multi-AP group ID for the second AP, or a multi-AP ID for the second AP.

[0211] According to various embodiments, a first AP may receive response frames (e.g., a CTS frame) to a TXOP shared frame from one or more APs. The RA field of the response frames may include the address of a second AP included in the RA field of the TXOP shared frame.

[0212] According to various embodiments, a first AP may receive a response frame to a TXOP shared frame from a second AP among one or more APs. The RA field of the response frame may include the address of the second AP included in the RA field of the TXOP shared frame.

[0213] According to various embodiments, a first AP may receive at least one response frame for a TXOP shared frame from at least one AP that transmitted a selection response frame among one or more APs. The RA field of the at least one response frame may include the address of a second AP included in the RA field of the TXOP shared frame.

[0214] According to various embodiments, information about at least one AP that has transmitted a selection response frame may be included in at least one of a selection request frame or a TXOP shared frame. The information about at least one AP may include at least one of an address of at least one AP, a basic service set (BSS) identifier (ID) of at least one AP, a BSS color of at least one AP, a multi-AP group ID of at least one AP, or a multi-AP ID of at least one AP.

[0215] According to various embodiments, after a first AP transmits a TXOP shared frame to a second AP or receives at least one response frame to a TXOP shared frame, the first AP may transmit a CTS frame in which an RA field includes an address of the second AP.

[0216] According to various embodiments, the selection request frame may include at least one of a trigger frame, a multi-user (MU)-request-to-send (RTS) trigger frame, a MU-RTS TXOP sharing (TXS) trigger frame, or a buffer status report poll (BSRP) trigger frame. The selection response frame may include at least one of a quality of service (QoS) null frame, a QoS data frame, a clear-to-send (CTS) frame, a CTS-to-Self frame, a block acknowledgement (BA) frame, or an action frame.

[0217] FIG. 21 illustrates an example of a method performed by a second AP for TXOP sharing for multiple APs according to an embodiment of the present disclosure. The second AP may be a DAP.

[0218] Referring to FIG. 21, the second AP can perform a negotiation procedure for multi-AP cooperation with one or more other APs.

[0219] In step S2103, the second AP can obtain settings for a set of APs for multi-AP cooperation based on a negotiation procedure.

[0220] In step S2105, the second AP may receive a selection request frame from the first AP in the set of APs, requesting selection of one or more APs for TXOP sharing (or whether one or more APs participate in TXOP sharing) in the set of APs. The duration field of the selection request frame may include information about an initial time period until the TXOP sharing frame is transmitted to the second AP, from among the one or more APs, to which the TXOP sharing frame is first transmitted.

[0221] In step S2107, the second AP may transmit a selection response frame to the selection request frame to the first AP.

[0222] In step S2109, the second AP may receive a TXOP shared frame from the first AP upon expiration of the initial time interval.

[0223] According to various embodiments, the duration field of the TXOP shared frame may include at least one of information about a remaining TXOP interval or information about an allocated interval allocated to a second AP. The remaining TXOP interval may be a time interval after the TXOP shared frame is transmitted in the entire TXOP interval.

[0224] According to various embodiments, after transmitting a TXOP shared frame to a second AP, a first AP may transmit a TXOP shared frame to a third AP among one or more APs. In this case, the duration field of the TXOP shared frame transmitted to the second AP may include information regarding the time period until the TXOP shared frame is transmitted to the third AP.

[0225] According to various embodiments, after transmitting a TXOP shared frame to a second AP, a first AP may not transmit a TXOP shared frame to any of the one or more APs. In this case, the duration field of the TXOP shared frame transmitted to the second AP may include information about the remaining TXOP period.

[0226] Below, a detailed implementation of TXOP sharing for multiple APs is described.

[0227] The present disclosure provides various embodiments for alternatives to issues that may arise when sharing a TXOP among multiple APs in Co-TDMA, and for setting specific frame sequences, signaling and / or duration fields.

[0228] For example, a method is provided for setting a duration field value of an MU-RTS TXS TF that can be transmitted in a TXOP sharing procedure to support Co-TDMA-based transmission.

[0229] For example, sequences are provided to support efficient Co-TDMA based transmission to multiple APs.

[0230] I. Setting the Duration / ID field

[0231] A method is provided for setting the duration / ID field value of an MU-RTS TXS TF that can be transmitted to share a TXOP for multiple APs in Co-TDMA. An AP that acquires a TXOP and acts as an SAP can initiate a procedure based on the TXOP by transmitting a trigger frame (e.g., MU-RTS TF, MU-RTS TXS TF) to perform individual FE and / or TXOP sharing with STAs within its BSS, wherein the trigger frame can include a duration / ID field.

[0232] FIG. 22 illustrates an example of setting a duration field of a trigger frame transmitted in a multi-AP selection procedure according to an embodiment of the present disclosure.

[0233] Referring to Fig. 22, for the multi-AP selection procedure (or schedule notification procedure), the SAP may set the value of the Duration / ID field in the trigger frame (i.e., selection request frame) to the duration (or initial time / duration) value until the time when the TXOP is first shared with the DAP (i.e., the DAP is the first to receive the TXOP among the DAPs). Accordingly, the initial duration of the SAP (i.e., Initial time in Fig. 22) may end when the TXOP is first shared with the DAP (e.g., DAP1).

[0234] When sharing TXOP with only one DAP for Co-TDMA operation, the Duration / ID field of the MU-RTS TXS TF may contain a remaining TXOP duration value. That is, the duration field may contain a value that is the total duration for Co-TDMA operation initially scheduled by the SAP minus the time used for individual FEs within its BSS (i.e., Initial time in Fig. 22). Alternatively, the SAP may set the allocation interval value that it wants to allocate to the DAP (i.e., the value of the allocation interval field in the user information field) to a value corresponding to the remaining TXOP, and set this value as the Duration field value of the MU-RTS TXS TF.

[0235] On the other hand, when sharing a TXOP to sequentially support Co-TDMA-based transmission to two or more DAPs, a protection issue may occur for subsequent DAPs, so the Duration / ID field of the MU-RTS TXS TF needs to contain a value with a shorter duration than the remaining TXOP duration. For example, if the Duration / ID field of the MU-RTS TXS TF delivered when sharing a TXOP to the first DAP contains a value corresponding to the total remaining TXOP remaining in the SAP, subsequent DAPs and / or STAs that receive this MU-RTS TXS TF will set the default NAV for the entire remaining TXOP period, and thus may not be able to perform FE (or UL TB PPDU transmission) during the allocated time thereafter.

[0236] Therefore, the duration / ID field of the MU-RTS TXS TF that can be transmitted for multi-AP TXOP sharing in Co-TDMA may include a duration value until the scheduled TXOP sharing time for the subsequent DAP.

[0237] FIG. 23 illustrates an example of setting the duration field of a frame transmitted for TXOP sharing among multiple APs according to an embodiment of the present disclosure. In FIG. 23, it is assumed that SAP has scheduled DAP 1, DAP 3, and DAP 2 to sequentially share TXOP.

[0238] Referring to Fig. 23, SAP can end the initial duration (i.e., Initial time in Fig. 23) at the time of performing the TXOP sharing scheduled to DAP 1. At this time, the duration field of the MU-RTS TXS TF transmitted to DAP 1 can include a value of the duration until the time of sharing the TXOP to the next scheduled DAP 3 (i.e., Allocated time to DAP 1 in Fig. 23). That is, the duration value included in the duration field of the MU-RTS TXS TF can mean the period until the time of transmitting the MU-RTS TXS TF to DAP 3. After this, the duration field of the MU-RTS TXS TF transmitted to DAP 3 may include 1) a value of the duration until the time of sharing the TXOP with the DAP scheduled for the next order (e.g., the duration until the time of transmitting the MU-RTS TXS TF to DAP 2 in FIG. 23), or 2) a value of the duration corresponding to the remaining TXOP remaining in the SAP, if there is no DAP scheduled for the next order.

[0239] II. TXOP Sharing Sequence for Multiple APs

[0240] In Co-TDMA, sequences are provided for sequentially sharing TXOPs among multiple APs. In TXOP sharing procedures / sequences for multiple APs, the duration field of a frame (e.g., a trigger frame, MU-RTS (TXS) TF) may be set as described above.

[0241] FIG. 24 illustrates a first example of a sequence in which all APs participating in multi-AP cooperation respond to an MU-RTS TXS TF according to an embodiment of the present disclosure.

[0242] Referring to FIG. 24, when APs in a group including APs cooperating for Co-TDMA operation receive an MU-RTS TXS TF for TXOP sharing transmitted from a SAP, all APs that received the MU-RTS TXS TF can transmit a response frame (e.g., a CTS frame) to the MU-RTS TXS TF.

[0243] A SAP can perform TXOP sharing for Co-TDMA-based transmission by transmitting an MU-RTS TXS TF in which the RA field includes the BSSID of DAP 1 with which it wishes to share TXOP and / or the AID12 field of the user information field includes BSS color, multi-AP group ID and / or multi-AP ID. Upon receiving this MU-RTS TXS TF, DAP 1 (i.e., a target DAP for TXOP sharing) transmits a CTS-to-self frame in which its own address is included in the RA field, and other APs participating in Co-TDMA-based cooperation (i.e., DAPs 2 and 3) can transmit CTS frames in which the address of DAP 1 is included in the RA field in response. That is, DAP 2 and DAP 3 can set the value of the RA field of the MU-RTS TXS TF transmitted by the SAP to the value of the RA field of the CTS frame that they transmit. Therefore, in order for DAP 2 and DAP 3 to transmit CTS frames set to the address of DAP 1, the RA field in the MU-RTS TXS TF must be set to the address of the target DAP 1. On the other hand, STAs that receive the MU-RTS TXS TF transmitted by the SAP but do not participate in multi-AP cooperation may not transmit CTS frames.

[0244] A SAP can perform TXOP sharing for Co-TDMA-based transmission by transmitting an MU-RTS TXS TF in which the RA field contains the BSSID of the DAP 3 that wants to share the TXOP with DAP 1 next and / or the AID12 field of the User Information field contains the BSS color, the Multi-AP Group ID and / or the Multi-AP ID. Similar to how DAP 1 received the TXOP first, DAP 3 transmits a CTS-to-self frame with its own address included in the RA field, and other APs participating in Co-TDMA-based cooperation (i.e., DAP 1 and 2) can transmit CTS frames in response with the address of DAP 3 included in the RA field.

[0245] FIG. 25 illustrates a second example of a sequence in which all APs participating in multi-AP cooperation respond to an MU-RTS TXS TF according to an embodiment of the present disclosure. In FIG. 25 , a NAV timeout issue (i.e., an issue in which a DAP receives an MU-RTS TXS TF but resets the NAV timer due to no subsequent PPDU reception) may be considered.

[0246] Referring to FIG. 25, when APs in a group including APs cooperating for Co-TDMA operation receive an MU-RTS TXS TF for TXOP sharing transmitted from a SAP, all APs that received the MU-RTS TXS TF can transmit a response frame (e.g., a CTS frame) to the MU-RTS TXS TF.

[0247] A SAP can perform TXOP sharing for Co-TDMA-based transmission by transmitting an MU-RTS TXS TF in which the RA field includes the BSSID of DAP 1 with which it wishes to share TXOP and / or the AID12 field of the user information field includes BSS color, multi-AP group ID and / or multi-AP ID. Upon receiving this MU-RTS TXS TF, DAP 1 (i.e., a target DAP for TXOP sharing) transmits a CTS-to-self frame in which its own address is included in the RA field, and other APs participating in Co-TDMA-based cooperation (i.e., DAPs 2 and 3) can transmit CTS frames in which the address of DAP 1 is included in the RA field in response. That is, DAP 2 and DAP 3 can set the value of the RA field of the MU-RTS TXS TF transmitted by the SAP to the value of the RA field of the CTS frame that they transmit. On the other hand, STAs that receive the MU-RTS TXS TF transmitted by the SAP but do not participate in multi-AP cooperation may not transmit a CTS frame. Subsequently, the SAP may transmit a separate CTS frame with the RA field set to the address of DAP 1 to prevent the NAV timeout issue described above.

[0248] A SAP may perform TXOP sharing for Co-TDMA-based transmission by transmitting a MU-RTS TXS TF in which the RA field contains the BSSID of the DAP 3 that wishes to share the TXOP with DAP 1 next and / or the AID12 field of the User Information field contains the BSS color, the Multi-AP Group ID and / or the Multi-AP ID. Similar to how DAP 1 received the TXOP first, DAP 3 may transmit a CTS-to-self frame with its own address in the RA field, and other APs participating in Co-TDMA-based cooperation (i.e., DAP 1 and 2) may transmit CTS frames in response with the address of DAP 3 in the RA field. Afterwards, the SAP may transmit a separate CTS frame with the RA field set to the address of DAP 3 to avoid the NAV timeout issue described above.

[0249] When all APs participating in multi-AP cooperation transmit a CTS frame in response to the MU-RTS TXS TF as in FIGS. 24 and 25, the transmitted CTS frames may overlap on at least one channel including the primary channel, and thus, an SAP receiving the overlapped CTSs may not be able to clearly identify which DAP succeeded / failed in the response.

[0250] Therefore, a method is proposed in which among the APs participating in multi-AP cooperation, only the target DAP for current TXOP sharing responds to the MU-RTS TXS TF.

[0251] FIG. 26 illustrates a first example of a sequence in which only the target DAP for current TXOP sharing among APs participating in multi-AP cooperation responds to the MU-RTS TXS TF according to an embodiment of the present disclosure.

[0252] Referring to FIG. 26, when APs within a group including APs cooperating for Co-TDMA operation receive an MU-RTS TXS TF for TXOP sharing transmitted from a SAP, only the target DAP for the current TXOP sharing can transmit a response frame (e.g., a CTS frame) to the MU-RTS TXS TF.

[0253] A SAP may perform TXOP sharing for Co-TDMA-based transmission by transmitting an MU-RTS TXS TF in which the RA field includes the BSSID of DAP 1 with which the SAP wishes to share TXOP and / or the AID12 field of the user information field includes a BSS color, a multi-AP group ID and / or a multi-AP ID. DAP 1 (i.e., a target DAP for TXOP sharing) receiving such MU-RTS TXS TF may transmit a CTS-to-self frame in which its own address is included in the RA field, and other APs participating in Co-TDMA-based cooperation (i.e., DAPs 2 and 3) and STAs not participating in multi-AP cooperation may not transmit CTS frames. Alternatively, DAP 1 (i.e., a target DAP for TXOP sharing) receiving the MU-RTS TXS TF may transmit a CTS frame in which the address of the SAP is included in the RA field.

[0254] A SAP may perform TXOP sharing for Co-TDMA-based transmission by transmitting an MU-RTS TXS TF in which the RA field includes the BSSID of the DAP 3 that wishes to share the TXOP with DAP 1 next and / or the AID12 field of the User Information field includes BSS color, multi-AP group ID and / or multi-AP ID. Similar to DAP 1 receiving the TXOP first, DAP 3 transmits a CTS-to-self frame in which its own address is included in the RA field, and other APs participating in Co-TDMA-based cooperation (i.e., DAP 1 and 2) and STAs that do not participate in multi-AP cooperation may not transmit CTS frames. Alternatively, DAP 3 receiving the MU-RTS TXS TF may transmit a CTS frame in which the address of the SAP is included in the RA field.

[0255] FIG. 27 illustrates a second example of a sequence in which, among APs participating in multi-AP cooperation, only the target DAP for current TXOP sharing responds to the MU-RTS TXS TF according to an embodiment of the present disclosure. In FIG. 27, a NAV timeout issue (i.e., an issue in which a DAP receives an MU-RTS TXS TF but resets the NAV timer due to no subsequent PPDU reception) may be considered.

[0256] Referring to FIG. 27, when APs within a group including APs cooperating for Co-TDMA operation receive an MU-RTS TXS TF for TXOP sharing transmitted from a SAP, only the target DAP for the current TXOP sharing can transmit a response frame (e.g., a CTS frame) to the MU-RTS TXS TF.

[0257] A SAP may perform TXOP sharing for Co-TDMA-based transmission by transmitting an MU-RTS TXS TF in which the RA field includes the BSSID of DAP 1 with which the SAP wishes to share TXOP and / or the AID12 field of the user information field includes a BSS color, a multi-AP group ID and / or a multi-AP ID. DAP 1 (i.e., a target DAP for TXOP sharing) receiving such MU-RTS TXS TF may transmit a CTS-to-self frame in which its own address is included in the RA field, and other APs participating in Co-TDMA-based cooperation (i.e., DAPs 2 and 3) and STAs not participating in multi-AP cooperation may not transmit CTS frames. Alternatively, DAP 1 (i.e., a target DAP for TXOP sharing) receiving the MU-RTS TXS TF may transmit a CTS frame in which the address of the SAP is included in the RA field. Next, SAP can send a separate CTS frame with the RA field set to the address of DAP 1 to prevent the NAV timeout issue described above.

[0258] A SAP may perform TXOP sharing for Co-TDMA-based transmission by transmitting an MU-RTS TXS TF in which the RA field includes the BSSID of the DAP 3 that wishes to share the TXOP with DAP 1 next and / or the AID12 field of the User Information field includes BSS color, multi-AP group ID and / or multi-AP ID. Similar to DAP 1 receiving the TXOP first, DAP 3 transmits a CTS-to-self frame in which its own address is included in the RA field, and other APs participating in Co-TDMA-based cooperation (i.e., DAP 1 and 2) and STAs that do not participate in multi-AP cooperation may not transmit CTS frames. Alternatively, DAP 3 receiving the MU-RTS TXS TF may transmit a CTS frame in which the address of the SAP is included in the RA field. Afterwards, SAP can send a separate CTS frame with the RA field set to the address of DAP 3 to prevent the NAV timeout issue described above.

[0259] According to the TXOP sharing sequence for multiple APs such as FIGS. 26 and 27, the SAP can clearly identify whether the CTS frame has been successfully transmitted from the target DAP for TXOP sharing, and can immediately perform PIFS recovery if the CTS frame is not received after the MU-RTS TXS TF transmission. That is, the waste of medium can be reduced when a CTS transmission failure occurs.

[0260] In some implementations, only the cooperating APs that have been determined as targets of TXOP sharing through a pre-negotiation procedure and / or the APs that have been targeted for TXOP sharing by transmitting a response frame (or CTS frame) in a multi-AP selection procedure (or schedule announcement procedure) may respond to the MU-RTS TXS TF. To signal (or indicate) these cooperating APs, the SAP may include a BSSID, a BSS color, a multi-AP group ID, and / or a multi-AP ID for one or more APs in the TF (e.g., MU-RTS TF) transmitted in the multi-AP selection procedure (or schedule announcement procedure) and / or in the MU-RTS TXS TF transmitted for TXOP sharing. Specifically, user information fields corresponding to one or more APs may be present in the user information list field.

[0261] FIG. 28 illustrates a first example of a sequence in which only APs selected for TXOP sharing among APs participating in multi-AP cooperation respond to MU-RTS TXS TF according to an embodiment of the present disclosure.

[0262] Referring to FIG. 28, only APs that have transmitted a response frame (e.g., Multi-STA BA frame or CTS frame) in the multi-AP selection procedure (or schedule announcement procedure) performed by the SAP in a group including APs that have cooperated for Co-TDMA operation and / or APs that have been determined as targets of TXOP sharing through a pre-negotiation procedure can transmit a response frame (e.g., CTS frame) for the MU-RTS TXS TF. That is, the SAP can request APs that have transmitted a response frame in the multi-AP selection procedure / schedule announcement procedure (e.g., procedure for exchanging TF and resp frames in FIG. 28) and / or APs that have been scheduled through pre-negotiation to respond by transmitting a CTS frame when sharing multi-AP TXOP.

[0263] A SAP can perform TXOP sharing for Co-TDMA-based transmission by transmitting an MU-RTS TXS TF in which the RA field includes the BSSID of DAP 1 with which the TXOP is to be shared and / or the AID12 field of the user information field includes a BSS color, a multi-AP group ID and / or a multi-AP ID. Here, the user information list field of the MU-RTS TXS TF may include information (e.g., BSS color, multi-AP group ID and / or multi-AP ID) about DAP 3, which is a subsequent TXOP sharing target. DAP 1, which receives the MU-RTS TXS TF, transmits a CTS-to-self frame in which its own address is included in the RA field, and DAP 3, which is a subsequent TXOP sharing target, can respond to the MU-RTS TXS TF by transmitting a CTS frame in which the RA field includes the address of DAP 1. On the other hand, other DAPs (e.g., DAP 2) that participate in multi-AP cooperation but do not include information about themselves in the User Information List field of the MU-RTS TXS TF, and STAs that do not participate in multi-AP cooperation may not transmit a CTS frame. Alternatively, DAP 1 (i.e., the target DAP for TXOP sharing) that receives the MU-RTS TXS TF may transmit a CTS frame in which the address of the SAP is included in the RA field. DAP 3, which is the subsequent TXOP sharing target, may also transmit a CTS frame in which the RA field includes the address of the SAP.

[0264] A SAP can perform TXOP sharing for Co-TDMA-based transmission by transmitting an MU-RTS TXS TF in which the RA field includes the BSSID of a DAP 3 that wants to share a TXOP next to DAP 1 and / or the AID12 field of the User Information field includes a BSS color, a Multi-AP Group ID and / or a Multi-AP ID. In the same way that DAP 1 received the TXOP first, DAP 3 transmits a CTS-to-self frame with its own address included in the RA field, and DAP 1, which previously received the TXOP, can transmit a CTS frame with the address of DAP 3 included in the RA field. On the other hand, other DAPs (e.g., DAP 2) that participate in multi-AP cooperation but whose information about themselves is not included in the User Information List field of the MU-RTS TXS TF and STAs that do not participate in multi-AP cooperation may not transmit a CTS frame. Alternatively, DAP 3 (i.e., the target DAP for TXOP sharing) receiving the MU-RTS TXS TF can send a CTS frame with the address of the SAP included in the RA field. DAP 1, the pre-TXOP sharing target, can also send a CTS frame with the RA field including the address of the SAP.

[0265] FIG. 29 illustrates a second example of a sequence in which only APs selected for TXOP sharing among APs participating in multi-AP cooperation respond to an MU-RTS TXS TF according to an embodiment of the present disclosure. In FIG. 29 , a NAV timeout issue (i.e., an issue in which a DAP receives an MU-RTS TXS TF but resets the NAV timer due to no subsequent PPDU reception) may be considered.

[0266] Referring to FIG. 29, only APs that have transmitted a response frame (or CTS frame) in the multi-AP selection procedure (or schedule announcement procedure) performed by the SAP in a group including APs that have cooperated for Co-TDMA operation and / or APs that have been determined as targets of TXOP sharing through a pre-negotiation procedure can transmit a response frame (e.g., CTS frame) for the MU-RTS TXS TF. That is, the SAP can request APs that have transmitted a response frame in the multi-AP selection procedure / schedule announcement procedure (e.g., procedure for exchanging TF and resp frames in FIG. 29) and / or APs that have been scheduled through pre-negotiation to respond by transmitting a CTS frame when sharing multi-AP TXOP.

[0267] A SAP can perform TXOP sharing for Co-TDMA-based transmission by transmitting an MU-RTS TXS TF in which the RA field includes the BSSID of DAP 1 with which the TXOP is to be shared and / or the AID12 field of the user information field includes a BSS color, a multi-AP group ID and / or a multi-AP ID. Here, the user information list field of the MU-RTS TXS TF may include information (e.g., BSS color, multi-AP group ID and / or multi-AP ID) about DAP 3, which is a subsequent TXOP sharing target. DAP 1, which receives the MU-RTS TXS TF, transmits a CTS-to-self frame in which its own address is included in the RA field, and DAP 3, which is a subsequent TXOP sharing target, can respond to the MU-RTS TXS TF by transmitting a CTS frame in which the RA field includes the address of DAP 1. On the other hand, other DAPs (e.g., DAP 2) that participate in multi-AP cooperation but do not include information about themselves in the user information list field of the MU-RTS TXS TF, and STAs that do not participate in multi-AP cooperation may not transmit a CTS frame. Alternatively, DAP 1 (i.e., the target DAP for TXOP sharing) that receives the MU-RTS TXS TF may transmit a CTS frame in which the address of the SAP is included in the RA field. DAP 3, which is a subsequent TXOP sharing target, may also transmit a CTS frame in which the RA field includes the address of the SAP. Subsequently, the SAP may transmit a separate CTS frame in which the RA field is set to the address of DAP 1 to avoid the NAV timeout issue described above.

[0268] A SAP can perform TXOP sharing for Co-TDMA-based transmission by transmitting an MU-RTS TXS TF in which the RA field includes the BSSID of a DAP 3 that wants to share a TXOP next to DAP 1 and / or the AID12 field of the User Information field includes a BSS color, a Multi-AP Group ID and / or a Multi-AP ID. In the same way that DAP 1 received the TXOP first, DAP 3 transmits a CTS-to-self frame with its own address included in the RA field, and DAP 1, which previously received the TXOP, can transmit a CTS frame with the address of DAP 3 included in the RA field. On the other hand, other DAPs (e.g., DAP 2) that participate in multi-AP cooperation but whose information about themselves is not included in the User Information List field of the MU-RTS TXS TF and STAs that do not participate in multi-AP cooperation may not transmit a CTS frame. Alternatively, DAP 3 (i.e., the target DAP for TXOP sharing) that received the MU-RTS TXS TF can send a CTS frame with the address of the SAP in the RA field. DAP 1, the pre-TXOP sharing target, can also send a CTS frame with the RA field containing the address of the SAP. Afterwards, the SAP can send a separate CTS frame with the RA field set to the address of DAP 3 to avoid the NAV timeout issue described above.

[0269] According to the TXOP sharing sequence for multiple APs such as FIGS. 28 and 29, better protection can be provided to subsequent DAPs compared to the TXOP sharing sequence for multiple APs such as FIGS. 26 and 27.

[0270] The present disclosure provides various embodiments for alternatives to issues that may arise when sharing a TXOP among multiple APs in Co-TDMA, and for setting specific frame sequences, signaling and / or duration fields.

[0271] For example, a method is provided for setting a duration field value of an MU-RTS TXS TF that can be transmitted in a TXOP sharing procedure to support Co-TDMA based transmission.

[0272] For example, sequences are provided to support efficient Co-TDMA based transmission to multiple APs.

[0273] 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.

[0274] 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: performing a negotiation procedure for multi-AP cooperation with one or more other APs; acquiring a configuration for a set of APs for the multi-AP cooperation based on the negotiation procedure; transmitting a selection request frame to one or more APs for requesting selection of one or more APs for transmission opportunity (TXOP) sharing from the set of APs, wherein a duration field of the selection request frame includes information about an initial time duration until the TXOP sharing frame is transmitted to a second AP from among the one or more APs to which the TXOP sharing frame is first transmitted; receiving a selection response frame for the selection request frame from at least one AP including the second AP from among the one or more APs; And upon expiration of the initial time interval, an operation of transmitting the TXOP shared frame to the second AP.

[0275] For example, the processor (111) of FIG. 1, the processing chip (114) 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: performing a negotiation procedure for multi-AP cooperation with one or more other APs; acquiring a configuration for a set of APs for the multi-AP cooperation based on the negotiation procedure; receiving, from a first AP in the set of APs, a selection request frame for requesting selection of one or more APs for transmission opportunity (TXOP) sharing in the set of APs, wherein a duration field of the selection request frame includes information about an initial time duration until the TXOP sharing frame is transmitted to the second AP, to which the TXOP sharing frame is first transmitted among the one or more APs; transmitting, to the first AP, a selection response frame for the selection request frame; And upon expiration of the initial time interval, an operation of receiving the TXOP shared frame from the first AP.

[0276] 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.

[0277] 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 for performing 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: performing a negotiation procedure for multi-AP cooperation with one or more other APs; acquiring a configuration for a set of APs for the multi-AP cooperation based on the negotiation procedure; transmitting a selection request frame to one or more APs for requesting selection of one or more APs for sharing a TXOP (transmission opportunity) from the set of APs, wherein a duration field of the selection request frame includes information about an initial time duration until the TXOP sharing frame is transmitted to a second AP among the one or more APs to which the TXOP sharing frame is first transmitted; An operation of receiving a selection response frame for the selection request frame from at least one AP including the second AP among the one or more APs; and an operation of transmitting the TXOP shared frame to the second AP upon expiration of the initial time interval.

[0278] 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: performing a negotiation procedure for multi-AP cooperation with one or more other APs; obtaining settings for a set of APs for the multi-AP cooperation based on the negotiation procedure; An operation of receiving a selection request frame from a first AP in the set of APs to request selection of one or more APs for sharing a transmission opportunity (TXOP) in the set of APs, wherein a duration field of the selection request frame includes information about an initial time duration until the TXOP sharing frame is transmitted to the second AP to which the TXOP sharing frame is first transmitted among the one or more APs; an operation of transmitting a selection response frame for the selection request frame to the first AP; and an operation of receiving the TXOP sharing frame from the first AP upon expiration of the initial time duration.

[0279] 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).

[0280] 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.

[0281] 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.

[0282] 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.

[0283] 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.

[0284] 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.

[0285] Machine learning can be classified into supervised learning, unsupervised learning, and reinforcement learning depending on the learning method.

[0286] 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.

[0287] 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.

[0288] Additionally, the above-described technical features can be applied to wireless communication of robots.

[0289] 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.

[0290] 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.

[0291] Additionally, the above-described technical features can be applied to devices that support extended reality.

[0292] 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.

[0293] 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.

[0294] 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.

[0295] The present disclosure may have various advantageous effects.

[0296] For example, based on the TXOP sharing method for multiple APs proposed in the present disclosure, the SAP can perform signaling and / or set a duration field to sequentially perform TXOP sharing to multiple DAPs so as to minimize protection and / or hidden node issues.

[0297] 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.

[0298] 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 the first AP (access point) performs a negotiation procedure for multi-AP cooperation with one or more other APs; A step in which the first AP obtains settings for a set of APs for multi-AP cooperation based on the negotiation procedure; A step in which the first AP transmits a selection request frame to one or more APs to request selection of one or more APs for sharing a TXOP (transmission opportunity) from the set of APs, The duration field of the above selection request frame includes information about an initial time duration until the TXOP shared frame is transmitted to a second AP among the one or more APs to which the TXOP shared frame is first transmitted; A step in which the first AP receives a selection response frame for the selection request frame from at least one AP including the second AP among the one or more APs; and A method comprising the step of transmitting the TXOP shared frame to the second AP when the initial time interval expires.

2. In claim 1, the user information field for the second AP in the TXOP shared frame includes information about the allocation interval allocated to the second AP, A method in which the above allocation interval includes an interval in which frame exchange is performed by the second AP.

3. In claim 1, the duration field of the TXOP shared frame includes at least one of information about a remaining TXOP interval or information about an allocation interval allocated to the second AP. The above remaining TXOP interval is a time interval after the TXOP shared frame is transmitted in the entire TXOP interval.

4. In claim 1, after the first AP transmits the TXOP shared frame to the second AP, the method further includes a step of transmitting the TXOP shared frame to a third AP among the one or more APs. A method in which the duration field of the TXOP shared frame transmitted to the second AP includes information about the time period until the TXOP shared frame is transmitted to the third AP.

5. In claim 1, after the first AP transmits the TXOP shared frame to the second AP, the first AP does not transmit the TXOP shared frame to any of the one or more APs. A method in which the duration field of the TXOP shared frame transmitted to the second AP includes information about the remaining TXOP interval.

6. In claim 1, the TXOP shared frame includes information about the second AP, A method in which information about the second AP includes at least one of an address of the second AP, a BSS (basic service set) identifier (ID) of the second AP, a BSS color for the second AP, a multi-AP group ID for the second AP, or a multi-AP ID for the second AP.

7. In claim 1, the first AP further includes a step of receiving response frames for the TXOP shared frame from all of the one or more APs, A method in which the RA field of the above response frames includes the address of the second AP included in the RA field of the TXOP shared frame.

8. In claim 1, the first AP further includes a step of receiving a response frame for the TXOP shared frame from the second AP among the one or more APs, A method in which the RA field of the response frame includes the address of the second AP included in the RA field of the TXOP shared frame.

9. In claim 1, the first AP further includes a step of receiving at least one response frame for the TXOP shared frame from at least one AP among the one or more APs, A method wherein the RA field of at least one response frame includes the address of the second AP included in the RA field of the TXOP shared frame.

10. In claim 1, the information about the at least one AP is included in at least one of the selection request frame or the TXOP shared frame, A method in which information about the at least one AP includes at least one of an address of the at least one AP, a BSS (basic service set) identifier (ID) of the at least one AP, a BSS color for the at least one AP, a multi-AP group ID for the at least one AP, or a multi-AP ID for the at least one AP.

11. A method according to claim 1, further comprising the step of transmitting a CTS (clear-to-send) frame in which an RA field includes an address of the second AP after the first AP transmits the TXOP shared frame to the second AP or receives at least one response frame for the TXOP shared frame.

12. In claim 1, the selection request frame includes at least one of a trigger frame, a MU (multi-user)-RTS (request-to-send) trigger frame, a MU-RTS TXS (TXOP sharing) trigger frame, or a BSRP (buffer status report poll) trigger frame, A method wherein the above selection response frame includes at least one of a quality of service (QoS) null frame, a QoS data frame, a clear-to-send (CTS) frame, a CTS-to-Self frame, a block acknowledgment (BA) frame, or an action frame.

13. In the first AP (access point), Transmitter and receiver; memory; and At least one processor functionally coupled with the transceiver and the memory, The memory stores instructions for performing operations based on being executed by the at least one processor, the operations being: An action to perform a negotiation procedure for multi-AP cooperation with one or more other APs; An operation of obtaining settings for a set of APs for multi-AP cooperation based on the above negotiation procedure; An operation of transmitting a selection request frame to one or more APs to request selection of one or more APs for sharing a TXOP (transmission opportunity) from the set of APs, The duration field of the above selection request frame includes information about an initial time duration until the TXOP shared frame is transmitted to a second AP among the one or more APs to which the TXOP shared frame is first transmitted; An operation of receiving a selection response frame for the selection request frame from at least one AP including the second AP among the one or more APs; and A first AP comprising an operation for transmitting the TXOP shared frame to the second AP upon expiration of the initial time interval.

14. In the device, at least one processor; and 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 being: An action to perform a negotiation procedure for multi-AP cooperation with one or more other APs; An operation of obtaining settings for a set of APs for multi-AP cooperation based on the above negotiation procedure; An operation of transmitting a selection request frame to one or more APs to request selection of one or more APs for sharing a TXOP (transmission opportunity) from the set of APs, The duration field of the above selection request frame includes information about an initial time duration until the TXOP shared frame is transmitted to a second AP among the one or more APs to which the TXOP shared frame is first transmitted; An operation of receiving a selection response frame for the selection request frame from at least one AP including the second AP among the one or more APs; and A device comprising an operation for transmitting the TXOP shared frame to the second AP upon expiration of the initial time interval.

15. A non-transitory computer readable medium (CRM) storing program code that implements instructions that perform operations based on being executed by at least one processor, wherein the operations are: An action to perform a negotiation procedure for multi-AP cooperation with one or more other APs; An operation of obtaining settings for a set of APs for multi-AP cooperation based on the above negotiation procedure; An operation of transmitting a selection request frame to one or more APs to request selection of one or more APs for sharing a TXOP (transmission opportunity) from the set of APs, The duration field of the above selection request frame includes information about an initial time duration until the TXOP shared frame is transmitted to a second AP among the one or more APs to which the TXOP shared frame is first transmitted; An operation of receiving a selection response frame for the selection request frame from at least one AP including the second AP among the one or more APs; and A CRM comprising an operation of transmitting the TXOP shared frame to the second AP upon expiration of the initial time interval.

16. A step in which a second AP (access point) performs a negotiation procedure for multi-AP cooperation with one or more other APs; A step in which the second AP obtains settings for a set of APs for multi-AP cooperation based on the negotiation procedure; A step in which the second AP receives a selection request frame from the first AP in the set of APs to request selection of one or more APs for sharing a transmission opportunity (TXOP) in the set of APs, The duration field of the selection request frame includes information about an initial time duration until the TXOP shared frame is transmitted to the second AP among the one or more APs to which the TXOP shared frame is first transmitted; A step in which the second AP transmits a selection response frame to the selection request frame to the first AP; and A method comprising the step of the second AP receiving the TXOP shared frame from the first AP upon expiration of the initial time interval.

17. In the second AP (access point), Transmitter and receiver; memory; and At least one processor functionally coupled with the transceiver and the memory, The memory stores instructions for performing operations based on being executed by the at least one processor, the operations being: An action to perform a negotiation procedure for multi-AP cooperation with one or more other APs; An operation of obtaining settings for a set of APs for multi-AP cooperation based on the above negotiation procedure; An operation of receiving a selection request frame from a first AP in the set of APs to request selection of one or more APs for sharing a transmission opportunity (TXOP) in the set of APs, The duration field of the selection request frame includes information about an initial time duration until the TXOP shared frame is transmitted to the second AP among the one or more APs to which the TXOP shared frame is first transmitted; An operation of transmitting a selection response frame to the selection request frame to the first AP; and A second AP comprising an operation of receiving the TXOP shared frame from the first AP upon expiration of the initial time interval.

18. In claim 17, the duration field of the TXOP shared frame includes at least one of information about a remaining TXOP interval or information about an allocation interval allocated to the second AP. The above remaining TXOP interval is the second AP, which is the time interval after the TXOP shared frame is transmitted in the entire TXOP interval.

19. In claim 17, the first AP transmits the TXOP shared frame to the second AP, and then transmits the TXOP shared frame to a third AP among the one or more APs. The duration field of the TXOP shared frame transmitted to the second AP includes information about the time period until the TXOP shared frame is transmitted to the third AP.

20. In claim 17, after the first AP transmits the TXOP shared frame to the second AP, the first AP does not transmit the TXOP shared frame to any of the one or more APs. The duration field of the TXOP shared frame transmitted to the second AP includes information about the remaining TXOP interval.

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