Method and device for sharing resources for wi-fi communication

Abstract

The present disclosure proposes an operation of an access point (AP) during Wi-Fi communication. According to one embodiment of the present disclosure, a method of a first AP may comprise: an operation of receiving target wake time (TWT) schedule information of a second AP broadcast by the second AP; an operation of confirming a TWT service period (SP) of the second AP on the basis of the TWT schedule information of the second AP; and an operation of acquiring a transmission opportunity (TXOP) period of the first AP on the basis of a time period required for frame exchange of the first AP and the TWT SP of the second AP.

Description

Method and device for sharing resources for Wi-Fi communication

[0001] The present disclosure relates to a method for sharing resources for Wi-Fi communication between devices.

[0002] Recently, with the advancement of wireless technology, wired networks are being replaced by wireless networks, which are widely used by many people. In other words, since wireless technology can overcome the mobility limitations of wired networks, many technologies utilizing wireless networks are being actively researched.

[0003] A Wireless Local Area Network (WLAN), also known as Wireless Fidelity (Wi-Fi), allows users to access the Internet via mobile devices or laptops within a certain distance from an Access Point (AP). The WiFi Alliance defines WiFi as a wireless local area network (WLAN) product based on the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard. WiFi communication primarily uses the 2.4 GHz and 5 GHz radio bands. In particular, with the popularization of mobile devices, WLANs, which have potential as open wireless networks, are rapidly expanding, and WiFi is being used to provide high-speed data services to entire cities, including schools, airports, hotels, and offices.

[0004] The Internet is evolving from a human-centric network where humans create and consume information to an Internet of Things (IoT) network where information is exchanged and processed between distributed components such as objects. The Internet of Everything (IoE) technology, which combines IoT technology with big data processing technology through connections to cloud servers, is also emerging. To implement the IoT, technological elements such as sensing technology, wired and wireless communication and network infrastructure, service interface technology, and security technology are required. Recently, technologies such as sensor networks for connecting objects, machine-to-machine (M2M) communication, and machine-type communication (MTC) are being researched.

[0005] In an IoT environment, intelligent IT (Internet Technology) services can be provided that collect and analyze data generated from connected objects, creating new value in human life. IoT, through the convergence and integration of existing IT (information technology) technologies with various industries, can be applied to fields such as smart homes, smart buildings, smart cities, smart or connected cars, smart grids, healthcare, smart appliances, and advanced medical services.

[0006] The present disclosure proposes a method for multiple devices to share resources during Wi-Fi communication.

[0007] According to one embodiment of the present disclosure, a method of a first access point (AP) performing Wi-Fi communication may include: receiving target wake time (TWT) schedule information of a second AP broadcasted by the second AP; confirming a TWT service period (SP) of the second AP based on the TWT schedule information of the second AP; and obtaining a transmission opportunity (TXOP) period of the first AP based on a time period required for frame exchange of the first AP and the TWT SP of the second AP.

[0008] According to one embodiment of the present disclosure, a first access point (AP) performing Wi-Fi communication may include a transceiver; and a control unit. The control unit may receive TWT (target wake time) schedule information of a second AP broadcasted by the second AP, confirm a TWT SP (service period) of the second AP based on the TWT schedule information of the second AP, and obtain a TXOP (Transmission Opportunity) period of the first AP based on a time period required for frame exchange of the first AP and the TWT SP of the second AP.

[0009] According to one embodiment of the present disclosure, an access point can ensure communication stability of other access points by acquiring a Transmission Opportunity (TXOP) by considering the Service Period (SP) of other access points.

[0010] According to one embodiment of the present disclosure, multiple access points can share TXOPs with the necessary access points without a separate negotiation procedure.

[0011] FIG. 1 is a drawing for explaining a short-range communication connection type of an electronic device according to one embodiment of the present disclosure.

[0012] FIG. 2 is a diagram illustrating the operation of an access point and a station for establishing a Wi-Fi connection according to one embodiment of the present disclosure.

[0013] FIG. 3 illustrates a wireless communication system including an access point and a wireless station according to one embodiment of the present disclosure.

[0014] FIG. 4 is a diagram for explaining a TWT (Target Wake Time) operation according to one embodiment of the present disclosure.

[0015] FIGS. 5A, 5B, 5C and 5D illustrate formats related to TWT according to one embodiment of the present disclosure.

[0016] FIGS. 6A, 6B, 6C, 6D, and 6E illustrate fields within a format related to a TWT according to one embodiment of the present disclosure.

[0017] FIG. 7 illustrates an example of an access point acquiring a Transmission Opportunity (TXOP) according to one embodiment of the present disclosure.

[0018] FIG. 8 illustrates an example of an Overlapping Basic Service Set (OBSS) between multiple access points according to one embodiment of the present disclosure.

[0019] FIG. 9 illustrates an example for explaining a TWT scheduling method between multiple access points according to one embodiment of the present disclosure.

[0020] FIG. 10 illustrates an example of an access point aligning a TWT SP (Service Period) start time based on a TBTT (target beacon transmission time) setting according to one embodiment of the present disclosure.

[0021] FIG. 11 illustrates an example for explaining how an access point sets a time interval considering an OBSS TWT SP according to one embodiment of the present disclosure.

[0022] FIG. 12 illustrates an example for explaining how an access point determines a minimum time interval for covering an OBSS TWT SP and performing frame exchange according to one embodiment of the present disclosure.

[0023] FIGS. 13a, 13b, 13c and 13d illustrate formats related to TWT for obtaining OBSS TWT SP information according to one embodiment of the present disclosure.

[0024] FIG. 14 illustrates an example for explaining a method of sharing AP TXOP according to a Cascading scheme according to one embodiment of the present disclosure.

[0025] FIG. 15 illustrates an example for explaining a method of sharing an AP TXOP according to a return method to an initial sharing AP according to one embodiment of the present disclosure.

[0026] FIG. 16 illustrates an example of a method for coordinating TWT SPs between access points according to one embodiment of the present disclosure.

[0027] FIG. 17 illustrates another example of a method for coordinating TWT SPs between access points according to one embodiment of the present disclosure.

[0028] FIG. 18 is a diagram showing an example configuration of an access point according to one embodiment of the present disclosure.

[0029] FIG. 19 is a diagram showing an example configuration of a station according to one embodiment of the present disclosure.

[0030] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the attached drawings.

[0031] In describing the embodiments, descriptions of technical details that are well known in the technical field to which the present disclosure pertains and are not directly related to the present disclosure will be omitted. This is to more clearly convey the gist of the present disclosure without obscuring it by omitting unnecessary explanations.

[0032] For the same reason, some components in the attached drawings are exaggerated, omitted, or schematically depicted. Furthermore, the dimensions of each component do not entirely reflect its actual size. Identical or corresponding components in each drawing are assigned the same reference numbers.

[0033] The advantages and features of the present disclosure, and methods for achieving them, will become clearer with reference to the embodiments described below in detail together with the accompanying drawings. However, the present disclosure is not limited to the embodiments disclosed below and may be implemented in various different forms. The embodiments of the present disclosure are provided only to make the present disclosure complete and to fully inform those skilled in the art of the scope of the disclosure, and the present disclosure is defined only by the scope of the claims. Like reference numerals refer to like elements throughout the specification.

[0034] At this time, it will be understood that each block of the processing flowchart drawings and combinations of the flowchart drawings can be performed by computer program instructions. These computer program instructions can be installed in a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing equipment, so that the instructions executed by the processor of the computer or other programmable data processing equipment create a means for performing the functions described in the flowchart block(s). These computer program instructions can also be stored in a computer-available or computer-readable memory that can direct a computer or other programmable data processing equipment to implement the functions in a specific manner, so that the instructions stored in the computer-available or computer-readable memory can also produce a manufactured item that includes an instruction means for performing the functions described in the flowchart block(s).

[0035] Since the computer program instructions may be installed on a computer or other programmable data processing device, a series of operational steps may be performed on the computer or other programmable data processing device to create a computer-executable process, so that the instructions that cause the computer or other programmable data processing device to perform the steps for performing the functions described in the flowchart block(s) may also be able to provide steps for performing the functions described in the flowchart block(s).

[0036] Additionally, each block may represent a module, segment, or portion of code that contains one or more executable instructions for performing a specific logical function(s). It should also be noted that in some alternative implementation examples, the functions described in the blocks may occur out of order. For example, two blocks depicted in succession may actually be executed substantially concurrently, or the blocks may sometimes be executed in reverse order, depending on their respective functions.

[0037] Here, the term '~ unit' used in the present embodiment means software or hardware components such as FPGA (Field Programmable Gate Array) or ASIC (Application Specific Integrated Circuit), and the '~ unit' performs certain roles. However, the '~ unit' is not limited to software or hardware. The '~ unit' may be configured to be on an addressable storage medium and may be configured to play one or more processors. Accordingly, according to some embodiments, the '~ unit' includes components such as software components, object-oriented software components, class components, and task components, processes, functions, properties, procedures, subroutines, segments of program code, drivers, firmware, microcode, circuits, data, databases, data structures, tables, arrays, and variables. The functions provided within the components and '~ units' may be combined into a smaller number of components and '~ units' or further separated into additional components and '~ units'. Additionally, the components and '~parts' may be implemented to activate one or more CPUs within the device or secure multimedia card. Furthermore, according to some embodiments, the '~parts' may include one or more processors.

[0038] The term 'electronic device', 'terminal' or 'station' used herein may refer to a mobile station (MS), user equipment (UE), user terminal (UT), wireless terminal, access terminal (AT), terminal, subscriber unit, subscriber station (SS), wireless device, wireless communication device, wireless transmit / receive unit (WTRU), mobile node, mobile or other terms. Various embodiments of the 'electronic device', 'terminal' or 'station' may include a cellular telephone, a smart phone having wireless communication capabilities, a personal digital assistant (PDA) having wireless communication capabilities, a wireless modem, a portable computer having wireless communication capabilities, a photographing device such as a digital camera having wireless communication capabilities, a gaming device having wireless communication capabilities, a music storage and playback appliance having wireless communication capabilities, an internet appliance capable of wireless internet access and browsing, as well as portable units or terminals incorporating combinations of such functions. Additionally, an 'electronic device', 'terminal', or 'station' may include, but is not limited to, an M2M (Machine to Machine) terminal, an MTC (Machine Type Communication) terminal / device. In this specification, an 'electronic device', 'terminal', or 'station' may also be simply referred to as a device.

[0039] The exemplary embodiments are described below for simplicity only with respect to Wireless Local Area Network (WLAN) systems. It should be understood that the exemplary embodiments are equally applicable to other wireless networks (e.g., cellular networks, pico-networks, femto-networks, satellite networks), as well as systems that utilize signals of one or more wired standards or protocols (e.g., Ethernet and / or HomePlug / PLC standards). As used herein, the terms "WLAN" and "Wi-Fi®" may include communications governed by the IEEE 802.11 standard, BLUETOOTH®, HiperLAN (a set of wireless standards, primarily used in Europe, comparable to the IEEE 802.11 standards), and other technologies having a relatively short radio propagation range. The terms "WLAN" and "WiFi" may be used interchangeably herein. Additionally, while described below with respect to an infrastructure WLAN system including one or more Access Points (APs) and a plurality of wireless stations (STAs), the exemplary embodiments are equally applicable to other WLAN systems including, for example, multiple WLANs, peer-to-peer (or independent basic service set) systems, Wi-Fi Direct systems, and / or hotspots.

[0040] Additionally, while the present disclosure describes the exchange of data frames between wireless devices, the exemplary embodiments may be applied to the exchange of any data unit, packet, and / or frame between wireless devices. Thus, the term "frame" may include any frame, packet, or data unit, such as, for example, protocol data units (PDUs), media access control (MAC) protocol data units (MPDUs), and physical layer convergence procedure (PLCP) protocol data units (PPDUs). The term "A-MPDU" may mean aggregated MPDUs.

[0041] In the following description, numerous specific details are set forth, such as examples of specific components, circuits, and processes, to provide a thorough understanding of the present disclosure. The term "connected," as used herein, means directly connected or connected via one or more intervening components or circuits. The term "connected access point" refers to an access point with which a given wireless station is currently associated and / or connected (e.g., there is an established communications channel or link between the access point and the given wireless station). Furthermore, in the following description and for purposes of explanation, specific nomenclature is set forth to provide a thorough understanding of the exemplary embodiments. However, it will be apparent to one skilled in the art that such specific details may not be necessary to practice the exemplary embodiments. In other instances, well-known circuits and devices are shown in block diagram form to avoid obscuring the present disclosure.

[0042] The operating principles of the present disclosure are described in detail below with reference to the attached drawings. In the following description of the present disclosure, detailed descriptions of related known functions or configurations will be omitted if they are deemed to unnecessarily obscure the gist of the present disclosure. Furthermore, the terms described below are defined based on the functions of the present disclosure and may vary depending on the intent or custom of the user or operator. Therefore, their definitions should be based on the overall content of this specification.

[0043] FIG. 1 is a drawing for explaining a short-range communication connection type of an electronic device according to one embodiment of the present disclosure.

[0044] Referring to FIG. 1, an electronic device (101) may be connected to an access point (AP) (200) based on Wi-Fi communication. The electronic device (101) may include a processor (120) and a communication module (190).

[0045] According to one embodiment, the communication module (190) may receive a signal from the outside or transmit a signal to the outside based on a Wi-Fi communication method (e.g., IEEE 802.11be-based communication). For example, the communication module (190) may operate based on IEEE 802.11ac, 802.11ax, 802.11be, or 802.11bn among Wi-Fi communication methods, and in particular, IEEE 802.11be or 802.11bn may support a wider bandwidth, higher data throughput, and shorter delay time compared to IEEE 802.11ax.

[0046] The communication module (190) may include a transceiver (191) for transmitting and receiving data with an external device and a communication processor (193) (e.g., a communication processor (not shown) or a short-range wireless communication module (e.g., a Wi-Fi chipset)). According to one embodiment, the communication module (190) may further include a memory.

[0047] According to one embodiment, the transceiver (191) may convert a baseband transmit signal into a wireless signal or convert a received wireless signal into a baseband receive signal.

[0048] According to various embodiments, the communication module (190) may further include, in addition to the transceiver (191) and the communication processor (193), components for orthogonal frequency division multiplexing (OFDM) or orthogonal frequency division multiple access (OFDMA), for example, a modulator, a digital-analog converter (D / A converter), a frequency converter, an A / D converter, an amplifier, and / or a demodulator.

[0049] Although not shown, according to various embodiments, the electronic device (101) may be electrically connected to a communication module of the access point (200) and may include at least one antenna module that supports a communication protocol and / or frequency band supported by the communication module of the access point (200).

[0050] According to one embodiment, the communication processor (193) may control the transceiver (191) to form a communication connection with the access point (200). For example, the communication connection may include a Wi-Fi network. For example, the communication processor (193) may control the transceiver (191) to form a wireless connection with the access point (200) using a 2.4 GHz, 5 GHz, or 6 GHz band wireless local area network (WLAN) standard such as IEEE 802.11ac, 802.11ax, 802.11be, or 802.11bn. Alternatively, the communication processor (193) may control the transceiver (191) to form a wireless connection with the access point (200) using a 60 GHz band WLAN standard such as IEEE 802.11ad or 802.11ay.

[0051] According to one embodiment, a method of communicating between an electronic device (101) and an access point (200) using a wireless local area network (WLAN) standard may be referred to as a communication method based on an STA mode.

[0052] According to one embodiment, the processor (120) may include an application processor. The processor (120) may perform a specified operation of the electronic device (101) or control other hardware (e.g., a communication module (190)) to perform a specified operation.

[0053] According to one embodiment, the access point (200) may support an operation of transmitting data to an external network and / or an operation of receiving data from an external network by a plurality of electronic devices (e.g., electronic device (101)) based on a connection between the plurality of electronic devices and an external network (e.g., the Internet, an external LAN, or a cellular network).

[0054] In one embodiment, the access point (200) may be a wireless router. The access point (200) may be a dedicated wireless router or a general-purpose device supporting mobile hotspot functionality, and there are no limitations on its implementation. For example, the access point (200) may include the same components as the electronic device (101).

[0055] According to one embodiment, the access point (200) can transmit and receive data with an external device, such as a server or an electronic device (101). For example, the access point (200) can transmit at least a portion of the data received from the server to the electronic device (101). According to one embodiment, the access point (200) and the electronic device (101) can transmit and receive UL (uplink) / DL (downlink) data during an operation period. For example, the access point (200) can transmit traffic to the electronic device (101) only during an operation period set based on schedule information received from the electronic device (101).

[0056] FIG. 2 is a diagram illustrating the operation of an access point and a station for establishing a Wi-Fi connection according to one embodiment of the present disclosure.

[0057] Referring to FIG. 2, an access point (210) may be implemented as the access point (200) of FIG. 1 and may communicate with a station (220) based on Wi-Fi. The station (220) may be implemented as the electronic device (101) of FIG. 1. The station (220) may be a terminal (or a terminal having a Wi-Fi interface) that supports Wi-Fi communication according to the IEEE 802.11 standard.

[0058] A station (220) may transmit (or broadcast) a probe request message to an access point (210) (S201). According to one embodiment, the probe request message may be a message for the station (220) to search for surrounding access points (210). According to one embodiment, the probe request message may include information regarding at least one communication capability supported by the station (220). According to one embodiment, the station (220) may receive a beacon message from the access point (210) and transmit a probe request message to the access point (210) based on information included in the beacon message. The access point (210) may transmit a probe response message (probe response) in response to the probe request message (S202).

[0059] Upon receiving the probe response message, the station (220) may transmit an authentication request message to the access point (210) (S203). The access point (210) may transmit an authentication response message to the station (220) in response to the authentication request message (S204), and the authentication procedure between the access point (210) and the station (220) may be completed. In one embodiment, the authentication procedures of S203 and S204 may be a procedure for selecting and authenticating a channel with the strongest reception strength among messages received during a channel search process. In one embodiment, through the authentication procedures of S203 and S204, the station (220) and the access point (210) may negotiate an encryption method of the authentication procedure.

[0060] Once the authentication procedure is completed, the station (220) may transmit an association request message to the access point (210) to establish a connection to the access point (210) (S205). According to one embodiment, the association request message may include information regarding at least one capability (e.g., according to the IEEE 802.11 standard) to be used for data communication between the station (220) and the access point (210). The access point (210) may generate an association ID (AID) for the station (220) and transmit an association response message to the station (220) (S206).

[0061] FIG. 3 illustrates a wireless communication system including an access point and a station according to one embodiment of the present disclosure.

[0062] Referring to FIG. 3, a wireless communication system (300) may include a wireless local area network (WLAN) (305) including an access point (310) and client electronic devices (320, 330, 332, 334, 336) corresponding to stations.

[0063] An access point (310) may form a wireless communication channel or link to one or more stations (STAs) (320, 330, 332, 334, 336). The access point (310) may be assigned a unique media access control (MAC) address.

[0064] Although WLAN (305) is illustrated as an infrastructure basic service set (BSS), in other exemplary embodiments, WLAN (305) may also be implemented as an independent basic service set (IBSS) network, or a peer-to-peer (P2P) network (e.g., operating according to Wi-Fi Direct protocols).

[0065] A station (any of 320, 330, 332, 334, 336) may be any suitable Wi-Fi enabled wireless or electronic device, including, for example, a cell phone, a personal digital assistant (PDA), a tablet device, a laptop computer, etc. A station (any of 320, 330, 332, 334, 336) may also be referred to as a user equipment (UE), a subscriber station, a mobile unit, a subscriber unit, a wireless unit, a remote unit, a mobile device, a wireless device, a wireless communication device, a remote device, a mobile subscriber station, an access terminal, a mobile terminal, a wireless terminal, a remote terminal, a handset, a user agent, a mobile client, a client, an electronic device, or any other suitable terminology.

[0066] Referring to FIG. 3, stations (320, 330, 332, 334, 336) may include one non-LL (legacy) client electronic device (320) that does not require low latency (LL) transmission and four LL client electronic devices (330, 332, 334, 336) that require low latency transmission. The traffic of the wireless stations (330, 332, 334, 336) that require low latency (LL) may require a certain traffic speed, for example, may require data transmission of 1500 bytes per 40 mm. In one embodiment, the four LL client electronic devices may include electronic devices that require low latency transmission and thus transmission through preemption or electronic devices that require high priority transmission.

[0067] Stations (330, 332, 334, 336) corresponding to UL clients connected to an access point (310) can use the “PCF (point coordination function) transmission method” and / or the “DCF (distributed coordination function) transmission method” for data transmission.

[0068] "PCF (point coordination function) method transmission" may refer to a method of transmission in which the access point directly asks the stations for data transmission and makes them wait for data transmission for multiple stations.

[0069] "DCF (distributed coordination function) transmission" may refer to a transmission method in which a station detects and waits in advance to avoid collisions before transmitting data in an environment where multiple stations compete to transmit data.

[0070] FIG. 4 is a diagram for explaining a TWT (Target Wake Time) operation according to one embodiment of the present disclosure.

[0071] Target Wake Time (TWT) can refer to the ability to put a station to sleep, sleep, and / or wake it up at a scheduled time. Access points (APs) can perform scheduling based on TWT to minimize contention among stations.

[0072] Figure 4 illustrates an example of a Broadcast TWT operation. The Broadcast TWT operation may refer to a method in which an access point that has received a TWT request message (TWT request) from a station broadcasts a TWT information element (IE).

[0073] Referring to FIG. 4, a first station (STA 1) can transmit a TWT request message (TWT request) requesting that the TWT function be activated to an access point (AP).

[0074] An access point (AP) may perform at least one operation related to optional target beacon transmission time (TBTT) negotiation. In one embodiment, the access point (AP) may determine (or set) at least one of a First TBTT and a Listen Interval through optional TBTT negotiation.

[0075] An access point (AP) may transmit a TWT response message (TWT response) corresponding to a TWT request message (TWT request). After transmitting the TWT response message (TWT response), the access point (AP) may broadcast a beacon message including a TWT IE in the Listen Interval after the First TBTT. In the present disclosure, the TWT IE may also be referred to as a TWT element.

[0076] In one embodiment, the beacon message may include at least one of a broadcast TWT ID for identifying a TWT and a MAC address of an access point (AP). In one embodiment, the beacon message may include TWT schedule information of the access point (AP). For example, if the broadcast TWT ID is set to a first value (broadcast TWT ID == 0), scheduling may be performed for all TWT scheduled stations, otherwise, scheduling may be performed for some TWT scheduled stations (member TWT scheduled stations). In one embodiment, the TWT IE in the beacon message includes one or more TWT parameter sets, each of which may indicate periodic occurrence of a TWT.

[0077] Each of the first station (STA 1) and the second station (STA 2) is set to a Doze state during the First TBTT, and when the First TBTT elapses, transitions to a wake-up state to receive a beacon message broadcast by an access point (AP). Each of the first station (STA 1) and the second station (STA 2) can transition from a wake-up state to a Doze state after receiving the beacon message.

[0078] An access point (AP) can broadcast a Basic Trigger message in a trigger-enabled TWT SP. For example, a first station (STA 1) that receives the Basic Trigger message can transmit a Poll message (PS-Poll) to the access point (AP). For example, a second station (STA 2) that receives the Basic Trigger message can transmit a QoS Null message to the access point (AP). The access point (AP) can broadcast a Multi-STA BlockAck message. Thereafter, the access point (AP) can broadcast a DL Multiuser Physical layer Protocol Data Unit (MU-PPDU). Thereafter, each of the first station (STA 1) and the second station (STA 2) can transmit a BlockAck message to the access point (AP). According to one embodiment, at least one of the first station (STA 1) and the second station (STA 2) that transmitted the BlockAck message can transition from a Wake-up state to a Doze state. Afterwards, the access point (AP) may broadcast at least one beacon message.

[0079] FIGS. 5A, 5B, 5C, and 5D illustrate formats related to TWT according to one embodiment of the present disclosure.

[0080] Figure 5a illustrates a TWT element format. Referring to Figure 5a, the TWT element format may include an Element ID field of 1 octet, a Length field of 1 octet, a Control field of 1 octet, and a TWT Parameter Information field of variable octet (variable length).

[0081] The Element ID field can be a value that identifies that the element format is a TWT element. According to the IEEE 802.11 standard, the value of the Element ID indicating the TWT element format can be 216.

[0082] The Length field can be a value expressing the length of the remaining fields excluding the lengths of the Element ID and Length fields in the corresponding element in octet units. In Fig. 5a, the value of the Length field can represent the sum of the lengths of the Control field and the TWT Parameter Information field.

[0083] The Control field is described in detail in Fig. 5b.

[0084] The TWT Parameter Information field follows the details of Figure 6a for the Individual TWT element, and follows the details of Figure 6b for the Broadcast TWT element.

[0085] Fig. 5b illustrates the format of the Control field included in the TWT element format. Referring to Fig. 5b, the format of the Control field may include an NDP Paging Indicator field, a Responder PM Mode field, a Negotiation Type field, a TWT Information Frame Disabled field, a Link ID Bitmap Present field, and an Aligned TWT field.

[0086] The NDP Paging Indicator field indicates the presence of the NDP Paging field in the TWT element format. If the value is 1, the NDP Paging field exists in the TWT element format.

[0087] The Responder PM mode field indicates whether power management mode operation is applied according to the IEEE 802.11 standard. If the value is 1, the STA operates in power management mode.

[0088] The Negotiation type field is a value that indicates whether the information contained in the TWT element is for broadcast TWT, individual TWT, or Wake TBTT interval.

[0089] If the Negotiation type subfield value is 0, the Target Wake Time subfield indicates the future individual TWT SP start time, and the TWT Wake Interval Mantissa and TWT Wake Interval Exponent subfields indicate the time interval between individual SPs.

[0090] When the Negotiation type subfield value is 1, the Target Wake Time subfield indicates the Next Wake TBTT time, and the TWT Wake Interval Mantissa and TWT Wake Interval Exponent subfields indicate the time interval between wake TBTTs.

[0091] When the Negotiation type subfield value is 2, the Target Wake Time subfield indicates the future broadcast TWT SP start time, and the TWT Wake Interval Mantissa and TWT Wake Interval Exponent subfields indicate the time interval between Broadcast TWT SPs.

[0092] When the Negotiation Type subfield value is 3, the Target Wake Time subfield indicates the future Broadcast TWT SP start time, and the TWT Wake Interval Mantissa and TWT Wake Interval Exponent subfields indicate the time interval between Broadcast TWT SPs. In addition, when the Negotiation Type subfield value is 3, the individually addressed Management frame can be used to manage the membership status of STAs within the broadcast TWT schedule.

[0093] If the value of the TWT Information frame disabled field is 1, this means that TWT Information frame reception is disabled by the STA. If it is 0, the STA receives the TWT Information frame.

[0094] The Wake duration unit field indicates the time unit of the Nominal Minimum TWT Wake Duration field. If the value is 0, the unit is 256 us, and if the value is 1, it means 1 UT.

[0095] The Link ID bitmap present field indicates whether the TWT element contains a Link ID bitmap. If the value is 1, the Link ID bitmap field is included in the TWT element.

[0096] The Aligned TWT field indicates that, for a Multi-Link Device (MLD), the TWTs between setup links operate under the same TWT parameters and that the TWT time points are aligned. If this value is 1, the Aligned TWT Link Bitmap field value is present.

[0097] Fig. 5c illustrates a TWT Parameter Information field (Individual TWT Parameter Set field format) included in the TWT element format in the case of an individual TWT. The Individual TWT Parameter Set field format may include a Request Type field, a Target Wake Time field, a TWT Group Assignment field, a Nominal Minimum TWT Wake Duration field, a TWT Wake Interval Mantissa field, a TWT Channel field, and an NDP Paging field (optional).

[0098] The Request Type field of Individual TWT follows Figure 6a.

[0099] The Target Wake Time field indicates a positive integer value corresponding to the TSF time at which the STA should be in the wake state.

[0100] The TWT Group Assignment field can be used to designate a TWT group when the TWT Grouping Support subfield of the S1G Capabilities element has a value of 1, and the TWT element does not include the Target Wake Time field, but instead includes the TWT Group Assignment field. The TWT Group Assignment field can include information about the TWT group to be assigned to the TWT requesting STA.

[0101] The Nominal Minimum TWT Wake Duration field indicates the minimum time that an STA must remain awake for frame exchange within the corresponding TWT SP, and the unit is 256 us.

[0102] The TWT Interval Mantissa field indicates the mantissa value of the TWT wake interval. The unit of the TWT wake interval is microsecond and the base value is 2.

[0103] The TWT Channel field represents, in bitmap format, the channel on which a TWT requesting STA will temporarily operate within a TWT SP (TWT Service Period) when negotiating an SST operation. Each bitmap corresponds to one minimum channel width, and the least significant bit corresponds to the lowest numbered channel on which a TWT responding STA (mainly an AP operating a BSS) operates.

[0104] The NDP Paging field may include P-ID, Max. NDP Paging Period, Partial TSF Offset, Action, Min Sleep Duration, and Reserved fields, and may include information that sets the TWT operation in conjunction with the NDP Paging operation.

[0105] FIG. 5d illustrates a TWT Parameter Information field (Broadcast TWT Parameter Set field format) included in the TWT element format in the case of broadcast TWT. The Broadcast TWT Parameter Set field format may include a Request Type field, a Target Wake Time field, a Nominal Minimum TWT Wake Duration field, a TWT Wake Interval Mantissa field, a Broadcast TWT Info field, and a Restricted TWT Traffic Info field (optional).

[0106] The Request Type of the Broadcast TWT element follows the detailed description in Fig. 6b.

[0107] The Target Wake Time field follows the description of the Target Wake Time field in FIG. 5c above.

[0108] The Nominal Minimum TWT Wake Duration field follows the description of Nominal Minimum TWT Wake Duration in FIG. 5c above.

[0109] The TWT Wake Interval Mantissa field follows the description of the TWT Wake Interval Mantissa field in FIG. 5c above.

[0110] The Broadcast TWT Info field follows the detailed description in Fig. 6c.

[0111] The Restricted TWT Traffic Info field follows the detailed description in Figure 6d.

[0112] FIGS. 6A, 6B, and 6C illustrate fields within a format related to a TWT according to one embodiment of the present disclosure.

[0113] Fig. 6a illustrates the format of the Request Type field included in the Individual TWT Parameter Set field illustrated in Fig. 5c. The format of the Request Type field may include a TWT Request field, a TWT Setup Command field, a Trigger field, an Implicit field, a Flow Type field, a TWT Flow Identifier field, a TWT Wake Interval Exponent field, and a TWT Protection field.

[0114] The TWT Request field has a value of 1 if the entity sending the TWT element is a TWT requesting STA or a TWT scheduled STA (usually an STA), and a value of 0 if the entity is a TWT responding STA or a TWT Scheduling AP (usually an AP).

[0115] The TWT Setup Command field indicates the Type of TWT command. The TWT Setup Command field is used to negotiate individual TWT or broadcast TWT. It is used as follows depending on each value: Request TWT (value == 0), Suggest TWT (value == 1), Demand TWT (value == 2), TWT Grouping (value == 3), Accept TWT (value == 4), Alternate TWT (value == 5), Dictate TWT (value == 6), Reject TWT (value == 7).

[0116] The Trigger field is an indicator indicating whether a trigger frame is transmitted within the TWT SP. If the value is 1, at least one trigger frame must be transmitted.

[0117] The Last Broadcast Parameter Set field is an indicator indicating whether this is the last broadcast TWT Parameter within the broadcast TWT element. A broadcast TWT element with a Last Broadcast Parameter Set value of 1 means that this is the last broadcast TWT parameter within the broadcast TWT element.

[0118] The Flow Type field indicates the type of interaction between a TWT requesting STA (or TWT scheduled STA) and a TWT responding STA (or TWT scheduling AP). A value of 0 indicates an announced TWT, and the TWT requesting STA (or TWT scheduled STA) must send a PS-Poll or APSD trigger frame to indicate that it is in an awake state before the TWT responding STA (or TWT scheduling AP) transmits a frame other than a trigger frame. A value of 1 indicates an unannounced TWT, and the TWT responding STA (or TWT scheduling AP) transmits a frame without a PS-Poll or APSD of the TWT requesting STA.

[0119] The TWT Flow Identifier field is a 3-bit value that is an identifier for identifying a specific TWT request when there are multiple TWT requests between the same TWT requesting STA and TWT responding STA pair.

[0120] The TWT Wake Interval Exponent field is used to represent the TWT wake interval value. The TWT wake interval is the average time interval between two consecutive TWT SP start times. The TWT Interval Exponent field represents the exponent value of the TWT wake interval value with a time unit of microseconds.

[0121] TWT wake interval =(TWT Wake Interval Mantissa)

[0122] The TWT Protection field indicates whether the TWT SP is protected, and a TWT responding STA can allocate a Restricted Access Window (RAW) that restricts channel access within the TWT SP by setting the TWT Protection field value to 1.

[0123] Fig. 6b illustrates the format of the Request Type field included in the Broadcast TWT Parameter Set field illustrated in Fig. 5d. The format of the Request Type field may include a TWT Request field, a TWT Setup Command field, a Trigger field, a Last Broadcast TWT Parameter Set field, a Flow Type field, a Broadcast TWT Recommendation field, a TWT Wake Interval Exponent field, and a Reserved field.

[0124] The TWT Request field has a value of 1 if the entity sending the TWT element is a TWT requesting STA or a TWT scheduled STA (usually an STA), and a value of 0 if the entity is a TWT responding STA or a TWT Scheduling AP (usually an AP).

[0125] The TWT Setup Command field indicates the Type of TWT command. The TWT Setup Command field is used to negotiate individual TWT or broadcast TWT. It is used as follows depending on each value: Request TWT (value == 0), Suggest TWT (value == 1), Demand TWT (value == 2), TWT Grouping (value == 3), Accept TWT (value == 4), Alternate TWT (value == 5), Dictate TWT (value == 6), Reject TWT (value == 7).

[0126] The Trigger field is an indicator indicating whether a trigger frame is transmitted within the TWT SP. If the value is 1, at least one trigger frame must be transmitted.

[0127] The Last Broadcast Parameter Set field is an indicator indicating whether this is the last broadcast TWT Parameter within the broadcast TWT element. A broadcast TWT element with a Last Broadcast Parameter Set value of 1 means that this is the last broadcast TWT parameter within the broadcast TWT element.

[0128] The Flow Type field indicates the type of interaction between a TWT requesting STA (or TWT scheduled STA) and a TWT responding STA (or TWT scheduling AP). A value of 0 indicates an announced TWT, and the TWT requesting STA (or TWT scheduled STA) must send a PS-Poll or APSD trigger frame to indicate that it is in an awake state before the TWT responding STA (or TWT scheduling AP) transmits a frame other than a trigger frame. A value of 1 indicates an unannounced TWT, and the TWT responding STA (or TWT scheduling AP) transmits a frame without a PS-Poll or APSD of the TWT requesting STA.

[0129] The Broadcast TWT Recommendation field is used to indicate the types of frames that the TWT scheduled STA and TWT scheduling AP can transmit during a broadcast TWT SP.

[0130] If the Broadcast TWT Recommendation field value is 0, there is no limit on the frames transmitted within the broadcast TWT SP.

[0131] When the Broadcast TWT Recommendation field value is 1, it is recommended that frames transmitted within the broadcast TWT SP be limited to solicited status and solicited feedback (e.g., PS-Poll, QoS Null frames, Feedback included in the QoS Control field or HE variant HT Control, Feedback within the HE TB feedback NDP, Bandwidth Query Report (BQR), Buffer Status Report (BSR), frames transmitted as part of the Sounding feedback exchange, and Control response frames). In addition, the Trigger frame transmitted by the TWT scheduling AP cannot include RUs for random access.

[0132] When the Broadcast TWT SP field value is 2, it is mostly the same as when the field value is 1, but there is a difference in that the Trigger frame transmitted by the TWT scheduling AP must include at least one RU for random access.

[0133] If the Broadcast TWT Recommendation field value is 3, there are no restrictions other than that the AP transmits a TIM frame or FILS Discovery frame containing the TIM element at the beginning of each TWT SP.

[0134] The TWT Wake Interval Exponent field is used to represent the TWT wake interval value. The TWT wake interval is the average time interval between two consecutive TWT SP start times. The TWT Interval Exponent field represents the exponent value of the TWT wake interval value with a time unit of microseconds.

[0135] TWT wake interval =(TWT Wake Interval Mantissa)

[0136] Fig. 6c illustrates the format of the Broadcast TWT Info field included in the Broadcast TWT Parameter Set field illustrated in Fig. 5d. The Broadcast TWT Info field may include a Restricted TWT Traffic Info Present field, a Restricted TWT Schedule Info field, a Broadcast TWT ID field, and a Broadcast TWT Persistance field.

[0137] The Restricted TWT Traffic Info Present field indicates the presence of the Restricted TWT Traffic Info field, and is present if the value is 1. For non-EHT STAs, this field value may be reserved for other purposes.

[0138] The Restricted TWT Schedule Info field is included when the Restricted TWT Parameter Set field is passed to a TWT element whose Negotiation Type field value is 2. If the value is 0, the corresponding R-TWT schedule means an 'idle R-TWT schedule', meaning that there are no member STAs or the schedule is suspended for all STAs.

[0139] If the Restricted TWT Schedule Info field value is 1, it means that the corresponding R-TWT schedule is an active R-TWT schedule, which means that there is at least one member STA in the corresponding R-TWT schedule.

[0140] If the Restricted TWT Schedule Info field value is 2, the R-TWT schedule is a full R-TWT schedule, and it means that the resources of the R-TWT schedule are insufficient or there are too many existing member STAs to accept a new STA as a member.

[0141] If the Restricted TWT Schedule Info field value is 3, the corresponding R-TWT schedule means that the advertised R-TWT schedule is activated and is for the AP corresponding to the nontransmitted BSSID that is a member of the same multiple BSSID set or co-hosted BSSID set that transmits the Restricted TWT Schedule Info field.

[0142] The Broadcast TWT ID field is used as an identifier to refer to a specific Broadcast TWT.

[0143] The Broadcast TWT Persistence field is a value expressed as the number of TBTTs, which is the time period during which the Broadcast TWT SP corresponding to the broadcast TWT parameter set is included. For example, a value of 10 means that the Broadcast TWT SP configured with the corresponding parameters will be operated during the time that 10 beacons are transmitted, and a value of 255 means that it is applied permanently.

[0144] FIG. 6d illustrates the format of the Restricted TWT Traffic Info field included in the Broadcast TWT Info field format. The Broadcast TWT Info field may include a Traffic Info Control field, a Restricted TWT DL TID Bitmap field, and a Restricted TWT UL TID Bitmap field.

[0145] The Traffic Info Control field follows the detailed description in Fig. 6e.

[0146] The Restricted TWT DL TID Bitmap field and the Restricted TWT UL Bitmap field represent TIDs (Traffic Identifiers) identified as latency sensitive traffic in the downlink and uplink directions, respectively, in bitmap format.

[0147] Figure 6e illustrates the format of the Traffic Info Control field included in the Restricted TWT Traffic Info field format. The Restricted TWT Traffic Info field includes a DL TID Bitmap Valid field, a UL TID Bitmap Valid field, and a Reserved field.

[0148] The DL TID Bitmap Valid and UL TID Bitmap Valid fields indicate whether the Restricted TWT DL TID Bitmap and Restricted TWT UL TID Bitmap fields of Fig. 6d are included, respectively. If the value is 1, the Restricted TWT DL TID Bitmap or Restricted TWT UL TID Bitmap field is included in the Restricted TWT Traffic Info field, and if the value is 0, all TIDs are classified as latency sensitive traffic in the corresponding R-TWT membership.

[0149] Meanwhile, for coordinated time division multiple access (C-TDMA), at least one of a negotiation operation between access points, a multi-AP coordination operation, and a multi-AP selection (selecting who will become a sharing AP) negotiation operation may be performed (or preceded). For C-TDMA, a procedure for discovering neighboring access points (neighbor APs) may be performed. For C-TDMA, a procedure for exchanging Request / Response frames between access points may be performed. For C-TDMA, a method may be performed in which a shared AP that initially receives TXOPs from a sharing AP returns at least a portion of the shared TXOPs to the sharing AP.

[0150] The present disclosure proposes a method for determining a TWT schedule by using a TWT element (or TWT IE) included in a Beacon and / or broadcast management frame of a surrounding Access Point (AP), by omitting or simplifying at least one of a negotiation procedure and a selection procedure. According to one embodiment, a shared AP that determines a TWT schedule by using the TWT element (or TWT IE) can be determined differently (or automatically) for each time interval. According to one embodiment, without a TXOP return procedure of the shared AP, an AP having the last TWT schedule in a TWT group can terminate the TXOP without returning it after using it, thereby maintaining a channel occupancy neutral state.

[0151] According to one embodiment, in a Coordinated Multi-AP environment, if TWT schedules operate adjacently and almost back-to-back within a specific time period, the TWT schedules can be grouped and managed (or processed). In the present disclosure, the grouped TWT SPs can be referred to as a TWT SP group. According to one embodiment, the TWT SP group can be determined based on a TWT SP start time interval (or expected TWT SP duration).

[0152] In one embodiment, an AP (sharing AP) with an earliest TWT SP start time can acquire sufficient TXOPs considering the TWT SP group (taking into account subsequent TWT SP(s)) and share the remaining TXOPs with the next AP (shared AP) after its own TWT SP ends. In one embodiment, an AP to acquire a TXOP can be automatically designated for each TWT SP group. In one embodiment, TXOP sharing can be performed between APs within a TXOP (a shared AP is automatically selected sequentially according to the contents of the TWT SP group).

[0153] In one embodiment, the Sharing AP may set the TXOP end time to be slightly longer than the start time of the latest TWT SP in the group (e.g., by setting T_margin) and may pass the TXOP to the next AP before the TWT SP of the next AP through the AP TXOP sharing procedure. In one embodiment, the Sharing AP may set the TXOP end time to be slightly longer than the start time of the next TWT SP and may transfer the TXOP to the shared AP after the end of its SP, and the shared AP that received the TXOP may operate as the Sharing AP and may set the TXOP end time to be slightly longer than the start time of the next TWT SP (chaining effect; in case of the last AP, the TXOP is extended by its expected SP). In one embodiment, the last shared AP may set CF-end as needed after the end of its SP.

[0154] According to one embodiment, an Overlapping Basic Service Set (OBSS) TWT SP Group may be formed based on a TWT SP start time interval after acquiring TWT schedule information between APs in a cooperative relationship. According to one embodiment, when attempting to acquire an Enhanced Distributed Channel Access (EDCA) TXOP, the TXOP duration may be set to include the entire duration of the OBSS TWT SP Group, and the AP may acquire the EDCA TXOP. After using the EDCA TXOP, the AP may share the TXOP with the OBSS. According to one embodiment, the TXOP duration may be set considering the AP TXOP Sharing procedure within the TWT group.

[0155] FIG. 7 illustrates an example of an access point acquiring a Transmission Opportunity (TXOP) according to an embodiment of the present disclosure. Referring to FIG. 7, a first access point (AP 1) may attempt to acquire an EDCA TXOP during a time period indicated by a TXOP duration. If the first access point (AP 1) acquires an EDCA TXOP during the time period indicated by the TXOP duration, other stations may delay access to the wireless medium using a Network Allocation Vector (NAV) during the time period (No Carrier Sensing).

[0156] FIG. 8 illustrates an example of an Overlapping Basic Service Set (OBSS) between multiple access points according to one embodiment of the present disclosure. Referring to FIG. 8, a first Basic Service Set (BSS) of a first access point (AP 1), a second BSS of a second access point (AP 2), and a third BSS of a third access point (AP 3) may overlap.

[0157] A BSS is a component of a WLAN, and access points (APs) and stations within the same BSS can communicate with each other. WLANs primarily use MAC-based communication, and BSSIDs are used to distinguish BSSs, which can be distinguished by MAC addresses. Stations can distinguish different BSSs using BSSIDs, and in an environment where the same SSID (Service Set ID) is being broadcast, stations can use BSSIDs to distinguish which AP to connect to.

[0158] FIG. 9 illustrates an example for explaining a TWT scheduling method between multiple access points according to one embodiment of the present disclosure.

[0159] Referring to FIGS. 8 and 9, the first BSS of the first access point (AP 1), the second BSS of the second access point (AP 2), and the third BSS of the third access point (AP 3) may partially overlap with each other.

[0160] A first access point (AP 1) can overhear beacons (OBSS beacons) broadcast by a third access point (AP 3) and obtain TWT schedule information of a BSS (OBSS) of the third access point (AP 3) from the beacons (OBSS beacons). In one embodiment, the first access point (AP 1) can obtain information about a TWT SP start time of the third access point (AP 3) by using the TWT schedule information of the third access point (AP 3).

[0161] A first access point (AP 1) can overhear beacons (OBSS beacons) broadcast by a second access point (AP 2) and obtain TWT schedule information of a BSS (OBSS) of the second access point (AP 2) from the beacons (OBSS beacons). In one embodiment, the first access point (AP 1) can obtain information about a TWT SP start time of the second access point (AP 2) using the TWT schedule information of the second access point (AP 2).

[0162] A first access point (AP 1) can set (or determine) a TWT schedule for access points within a set time interval based on TWT schedule information of a second access point (AP 2) and TWT schedule information of a third access point (AP 3). In one embodiment, the first access point (AP 1) can set (or determine) a TWT group including the first access point (AP 1), the second access point (AP 2), and the third access point (AP 3) for which one TWT schedule is set. In one embodiment, a candidate TWT group can be determined on the side of each access point.

[0163] When the TXOP end time of the first access point (AP 1) is close to the TWT SP start time of the second access point (AP 2) and / or the third access point (AP 3), the first access point (AP 1) can obtain an EDCA TXOP by considering the TWT SP of the second access point (AP 2) and / or the third access point (AP 3). The first access point (AP 1) can set the EDCA TXOP to be long so that the TWT SP of the second access point (AP 2) and / or the third access point (AP 3) is sufficiently secured. The first access point (AP 1) can obtain an EDCA TXOP including the OBSS TWT SP of the second access point (AP 2) and / or the third access point (AP 3).

[0164] When the first access point (AP 1) acquires EDCA TXOP during the time period indicated by TXOP duration, other stations can postpone access to the wireless medium using NAV (No carrier sensing) during that time period.

[0165] Figures 10 to 12 illustrate an example of how an access point extends a TXOP duration to secure (or cover) an OBSS TWT SP.

[0166] FIG. 10 illustrates an example of an access point aligning a TWT Service Period (SP) start time based on a target beacon transmission time (TBTT) setting according to an embodiment of the present disclosure. Referring to FIG. 10, a first access point (AP 1) sets the last TBTT as a starting point TBTT. kand align the TWT SP start time with the OBSS TWT schedule (e.g., the TWT schedule of the second access point (AP 2) and / or the TWT schedule of the third access point (AP 3) in FIG. 8).

[0167] FIG. 11 illustrates an example for explaining a method for an access point to set a time period considering an OBSS TWT SP according to an embodiment of the present disclosure. Referring to FIG. 11, a first access point (AP 1) may set a time period (TXOP duration) for determining a TXOP duration for obtaining an EDCA TXOP considering an OBSS TWT SP (e.g., a TWT schedule of a second access point (AP 2) and / or a TWT schedule of a third access point (AP 3) of FIG. 8).

[0168] The first access point (AP 1) may determine the TXOP duration by considering the expected OBSS TWT SP duration when performing EDCA in the shaded area. According to one embodiment, the expected OBSS TWT SP duration may be calculated based on the following mathematical expression 1.

[0169] [Mathematical Formula 1]

[0170] AdjustedMinimumTWTWakeDuration = Nominal Minimum TWT Wake Duration - The elapsed time from the scheduled start of the TWT SP to the actual start of the SP.

[0171] FIG. 12 illustrates an example for explaining a method for an access point to determine a minimum time period for covering an OBSS TWT SP and performing a frame exchange according to an embodiment of the present disclosure. Referring to FIG. 12, a first access point (AP 1) may determine a time period for its frame exchange (Time duration for AP1's frame exchange). The first access point (AP 1) may determine a time period that is required for my frame exchange plus the reserved time for the OBSS TWT SP followed by my transmission. According to an embodiment, the first access point (AP 1) may determine a minimum time period for covering OBSS TWT SPs after its frame exchange.

[0172] FIGS. 13a, 13b, 13c, and 13d illustrate formats related to TWT for obtaining OBSS TWT SP information according to one embodiment of the present disclosure.

[0173] Fig. 13a illustrates a TWT element format. Referring to Fig. 13a, the TWT element format may include an Element ID field of 1 octet, a Length field of 1 octet, a Control field of 1 octet, and a TWT Parameter Information field of variably octets. The description of the fields in the TWT element format of Fig. 13a is the same as that described above in Fig. 5a and is therefore omitted.

[0174] Fig. 13b illustrates the format of the Control field included in the TWT element format. Referring to Fig. 13b, the format of the Control field may include an NDP Paging Indicator field, a Responder PM Mode field, a Negotiation Type field, a TWT Information Frame Disabled field, a Link ID Bitmap Present field, and an Aligned TWT field. The description of the fields in the TWT element format of Fig. 13b is the same as that described above in Fig. 5b and is therefore omitted.

[0175] Fig. 13c illustrates a TWT Parameter Information field (Broadcast TWT Parameter Set field format) included in the TWT element format in the case of broadcast TWT. The Broadcast TWT Parameter Set field format may include a Request Type field, a Target Wake Time field, a Nominal Minimum TWT Wake Duration field, a TWT Wake Interval Mantissa field, a Broadcast TWT Info field, a Restricted TWT Traffic Info field (optional), and a C-TWT Info field. The description of the fields in the TWT element format of Fig. 13a is the same as that described above in Fig. 5d and is therefore omitted. A specific description of the C-TWT Info field is described later in Fig. 13d.

[0176] Figure 13d illustrates fields included in the C-TWT Info field of Figure 13c. The C-TWT Info field may include an Average TWT SP duration field, a Traffic Info field, and a Priority field.

[0177] The Average TWT SP duration field may indicate the average time duration of the corresponding TWT SP (i.e., TWT SP end time - TWT SP start time). The Average TWT SP duration field may indicate the Expected TWT SP duration, which may be a time average of the time duration from the TWT SP start time to the TWT SP end time. According to one embodiment, an OBSS AP that receives the Average TWT SP duration field may perform CR-TWT by taking this into consideration.

[0178] The Traffic Info field can indicate the characteristics of the traffic exchanged within the TWT SP (e.g., whether it is SCS (Stream Classification Service), whether it is Low Latency, etc.).

[0179] The Priority field indicates the importance of traffic within the TWT SP, so the OBSS AP can refer to this to more actively share TXOPs for high priority TWT SPs.

[0180] FIG. 14 illustrates an example for explaining a method of sharing AP TXOP according to a Cascading scheme according to one embodiment of the present disclosure.

[0181] Referring to FIG. 14, a first access point (AP1) can overcast a control frame (ICF) including shared information (TXS) of a TXOP. A second access point (AP2) receives (overhears) the control frame (ICF) including shared information (TXS) of a TXOP, and based on the shared information (TXS) of the TXOP, transmits the TXOP from the first access point (AP1) at a first time point ( ) can be confirmed (or assumed) that it is provided (or shared) from the second access point (AP2). The third access point (AP3) receives (overhears) a control frame (ICF) containing shared information (TXS) of the TXOP, and based on the shared information (TXS) of the TXOP, the TXOP is transmitted from the second access point (AP2) at the second time point ( ) can be confirmed (or assumed) to be provided (or shared).

[0182] According to one embodiment, a first access point (AP1) obtains a broadcast TWT element from a frame transmitted by a second access point (AP2), and, based on the broadcast TWT element, considers the TWT SP start time of the second access point (AP2) to determine a first point in time ( ) can be determined.

[0183] According to one embodiment, the first access point (AP1) may obtain a broadcast TWT element from a frame transmitted by the third access point (AP3) and determine the TWT SP start time of the third access point (AP3) based on the broadcast TWT element. According to one embodiment, the first access point (AP1) may determine that TXOP sharing is to be cascaded to the third access point (AP3) based on the expected TWT SP duration of the second access point (AP2) and the TWT SP start time of the third access point (AP3) included in the C-TWT element (e.g., the C-TWT Info field of FIG. 13c).

[0184] After transmitting the control frame (ICF), the first access point (AP1) can exchange at least one frame in its BSS.

[0185] First point ( ), the first access point (AP1) may perform a procedure for sharing a TXOP with the second access point (AP2). According to one embodiment, the procedure for sharing a TXOP may be performed through an RTS (request to send) and CTS (clear to send) exchange between the first access point (AP1) and the second access point (AP2).

[0186] The second access point (AP2) can overcast a control frame (ICF) containing shared information (TXS) of the TXOP. The third access point (AP3) receives (overhears) the control frame (ICF) containing shared information (TXS) of the TXOP, and based on the shared information (TXS) of the TXOP, transmits the TXOP from the second access point (AP2) at a second time point ( ) can be confirmed (or assumed) to be provided (or shared).

[0187] After the TWT SP start time of the second access point (AP2) after transmitting the control frame (ICF), the second access point (AP2) can exchange at least one frame in its BSS.

[0188] Second point of view ( ), the second access point (AP2) may perform a procedure for sharing a TXOP with a third access point (AP3). According to one embodiment, the procedure for sharing a TXOP may be performed through RTS and CTS exchange between the second access point (AP2) and the third access point (AP3).

[0189] After the procedure for sharing TXOP, from the TWT SP start time of the third access point (AP3), the third access point (AP3) can exchange at least one frame in its BSS.

[0190] FIG. 15 illustrates an example for explaining a method of sharing an AP TXOP according to a return method to an initial sharing AP according to one embodiment of the present disclosure.

[0191] Referring to FIG. 15, a first access point (AP1) can overcast a control frame (ICF) including shared information (TXS) of a TXOP. A second access point (AP2) receives (overhears) the control frame (ICF) including shared information (TXS) of a TXOP, and based on the shared information (TXS) of the TXOP, transmits the TXOP from the first access point (AP1) at a first time point ( ) can be confirmed (or assumed) that it is provided (or shared) from the second point in time ( ) . The third access point (AP3) receives (overhears) a control frame (ICF) containing shared information (TXS) of the TXOP, and based on the shared information (TXS) of the TXOP, the TXOP is transmitted from the first access point (AP2) at the second point in time ( ) can be confirmed (or assumed) to be provided (or shared).

[0192] According to one embodiment, a first access point (AP1) obtains a broadcast TWT element from a frame transmitted by a second access point (AP2), and, based on the broadcast TWT element, considers the TWT SP start time of the second access point (AP2) to determine a first point in time ( ) can be determined.

[0193] According to one embodiment, the first access point (AP1) can obtain a broadcast TWT element from a frame transmitted by the third access point (AP3) and determine the TWT SP start time of the third access point (AP3) based on the broadcast TWT element. According to one embodiment, the first access point (AP1) can determine a second time point (or point in time) at which the first access point (AP2) provides (or shares) a TXOP to the third access point (AP3) based on the expected TWT SP duration of the second access point (AP2) and the TWT SP start time of the third access point (AP3) included in the C-TWT element (e.g., the C-TWT Info field of FIG. 13c). ) can be determined.

[0194] After transmitting the control frame (ICF), the first access point (AP1) can exchange at least one frame in its BSS.

[0195] First point ( ), the first access point (AP1) may perform a procedure for sharing a TXOP with the second access point (AP2). According to one embodiment, the procedure for sharing a TXOP may be performed through an RTS and CTS exchange between the first access point (AP1) and the second access point (AP2).

[0196] From the TWT SP start time of the second access point (AP2), the second access point (AP2) can exchange at least one frame in its BSS. Thereafter, the second access point (AP2) can perform a procedure for returning a TXOP to the first access point (AP1).

[0197] According to one embodiment, a first access point (AP1) can optionally overcast a control frame (ICF) containing shared information (TXS) of a TXOP. A third access point (AP3) receives (overhears) the control frame (ICF) containing shared information (TXS) of a TXOP, and based on the shared information (TXS) of the TXOP, transmits the TXOP from the first access point (AP1) at a second time point ( ) can be confirmed (or assumed) to be provided (or shared). In one embodiment, the first access point (AP1) may not rebroadcast the control frame (ICF) containing the shared information (TXS) of the TXOP.

[0198] Second point of view ( ), the second access point (AP2) may perform a procedure for sharing a TXOP with a third access point (AP3). According to one embodiment, the procedure for sharing a TXOP may be performed through RTS and CTS exchange between the second access point (AP2) and the third access point (AP3).

[0199] After the procedure for sharing TXOP, from the TWT SP start time of the third access point (AP3), the third access point (AP3) can exchange at least one frame in its BSS.

[0200] In one embodiment, the control frame (ICF) of the Sharing AP providing (or sharing) TXOP may include an extension field including list information regarding TXOP sharing between access points. For example, the control frame (ICF) may be MU-RTS. In one embodiment, the list information may include an identifier of the shared AP (shared AP identifier) ​​and a TXOP sharing timestamp (TXOP sharing timestamp).

[0201] FIG. 16 illustrates an example of a method for coordinating TWT SPs between access points according to one embodiment of the present disclosure.

[0202] Referring to FIG. 16, when the TWT of the second access point (AP2) is a restricted TWT (R-TWT), the first access point (AP1) may terminate the frame exchange by considering the time taken for the TXOP sharing procedure before the TWT SP start time of the second access point (AP2). The R-TWT may be a TWT for transmitting and / or receiving traffic with a high priority. For example, R-TWT may be a TWT in which time-sensitive traffic receives a high priority and the service period may be adjusted. The first access point (AP1) may guarantee data transmission within the R-TWT SP of the second access point (AP2) before the R-TWT start time of the second access point (AP2).

[0203] A first access point (AP1) can broadcast a control frame (ICF) containing shared information (TXS) of a TXOP. A second access point (AP2) can overhear the control frame (ICF) containing shared information (TXS) of a TXOP.

[0204] After transmitting the control frame (ICF), the first access point (AP1) can transmit and / or receive at least one frame using TXOP (TXOP utilization).

[0205] A first access point (AP1) may perform a procedure for sharing a TXOP with a second access point (AP2). In one embodiment, the procedure for sharing a TXOP may be performed through an RTS and CTS exchange between the first access point (AP1) and the second access point (AP2).

[0206] After the procedure for sharing TXOP, from the TWT SP start time of the second access point (AP2), the second access point (AP2) can exchange at least one frame in its BSS (TXOP utilization).

[0207] FIG. 17 illustrates another example of a method for coordinating TWT SPs between access points according to one embodiment of the present disclosure.

[0208] Referring to FIG. 17, if the TWT of the second access point (AP2) is not R-TWT, the first access point (AP1) can conservatively set its TXOP end time and perform the TXOP sharing procedure at a time later than the TWT SP start time of the second access point (AP2).

[0209] A first access point (AP1) can broadcast a control frame (ICF) containing shared information (TXS) of a TXOP. A second access point (AP2) can overhear the control frame (ICF) containing shared information (TXS) of a TXOP.

[0210] After transmitting the control frame (ICF), the first access point (AP1) can transmit and / or receive at least one frame using TXOP (TXOP utilization).

[0211] The first access point (AP1) may utilize its TXOP as much as necessary, and provide (or share) the remaining TXOP to the second access point (AP2) after the frame exchange is completed. In one embodiment, the TXOP sharing time may be later than the TWT SP start time of the second access point (AP2), and the second access point (AP2) may utilize the channel without EDCA contention.

[0212] After the TWT SP start time of the second access point (AP2), the first access point (AP1) may perform a procedure for sharing a TXOP with the second access point (AP2). In one embodiment, the procedure for sharing a TXOP may be performed through an RTS and CTS exchange between the first access point (AP1) and the second access point (AP2).

[0213] After the procedure for sharing TXOP, from the TWT SP start time of the second access point (AP2), the second access point (AP2) can exchange at least one frame in its BSS (TXOP utilization).

[0214] In one embodiment, the last frame exchange in the previous BSS (the BSS of the sharing AP) may be utilized, and the TWT SP start time of the next BSS (the BSS of the shared AP) may be utilized. In one embodiment, if the last TXOP acquired by the sharing AP fails, the shared AP may acquire a TXOP to service the TWT SP as scheduled.

[0215] FIG. 18 is a diagram showing an example configuration of an access point according to one embodiment of the present disclosure.

[0216] In FIG. 18, the access point may include a processor (1801), a transceiver (1802), and a memory (1803). The processor (1801), the transceiver (1802), and the memory (1803) of the access point may operate according to the method(s) described in the above-described embodiments of FIGS. 1 to 17. However, the components of the access point are not limited to the above-described examples. For example, the access point may include more or fewer components than the above-described components. In addition, the processor (1801), the transceiver (1802), and the memory (1803) may be implemented in the form of at least one chip.

[0217] The transceiver (1802) is a general term for a receiver and a transmitter, and can transmit and receive signals with an access point or other network entity through the transceiver (1802). At this time, the transmitted and received signals may include at least one of control information and data. To this end, the transceiver (1802) may include an RF transmitter that up-converts and amplifies the frequency of a transmitted signal, and an RF receiver that low-noise amplifies and frequency-converts the received signal. This is only one embodiment of the transceiver (1802), and the components of the transceiver (1802) are not limited to the RF transmitter and RF receiver. In addition, the transceiver (1802) can receive a signal and output it to the processor (1801), and transmit the signal output from the processor (1801) to another network entity through the network.

[0218] The memory (1803) can store programs and data necessary for the operation of the access point according to at least one of the embodiments of FIGS. 1 to 17. In addition, the memory (1803) can store control information and / or data included in a signal acquired from the access point. The memory (1803) can be configured as a storage medium or a combination of storage media, such as a ROM, a RAM, a hard disk, a CD-ROM, and a DVD.

[0219] The processor (1801) may control a series of processes so that the access point can operate according to at least one of the embodiments of FIGS. 1 to 17. The processor (2101) may include at least one processor.

[0220] According to one embodiment, the processor (1801) may receive target wake time (TWT) schedule information of the second AP broadcasted by the second AP, determine a TWT service period (SP) of the second AP based on the TWT schedule information of the second AP, and obtain a TXOP (Transmission Opportunity) period of the first AP based on a time period required for frame exchange of the first AP and the TWT SP of the second AP.

[0221] According to one embodiment, the processor (1801) may receive TWT schedule information of the third AP broadcasted by the third AP, and determine the TWT SP of the third AP based on the TWT schedule information of the third AP. At this time, the TXOP period of the first AP may be obtained based on the time period required for the frame exchange of the first AP, the TWT SP of the second AP, and the TWT SP of the third AP.

[0222] According to one embodiment, the processor (1801) may determine that an interval between an end time of a time interval required for the frame exchange of the first AP and a start time of the TWT SP of the second AP is less than or equal to a set threshold value, and may determine to use the TWT SP of the second AP when acquiring the TXOP interval of the first AP.

[0223] In one embodiment, the first basic service set (BSS) of the first AP, the second BSS of the second AP, and the third BSS of the third AP may overlap each other.

[0224] According to one embodiment, the processor (1801) may broadcast a control frame including a first point in time at which the first AP shares a TXOP with the second AP, and a second point in time at which the second AP shares a TXOP with the third AP.

[0225] According to one embodiment, the processor (1801) may determine the first point in time based on a start point in time of the TWT SP of the second AP, and may determine the second point in time based on an average TWT SP time of the second AP and a start point in time of the TWT SP of the third AP.

[0226] According to one embodiment, the processor (1801) may broadcast a control frame including a first point in time at which the first AP shares a TXOP with the second AP, and a second point in time at which the first AP shares a TXOP with the third AP.

[0227] According to one embodiment, the processor (1801) may receive the TXOP returned from the second AP before the second time point.

[0228] According to one embodiment, the TWT schedule information of the second AP may include an average TWT SP time of the second AP, information about traffic exchanged within the TWT SP of the second AP, and information indicating a priority of the traffic.

[0229] According to one embodiment, the processor (1801) may perform a TXOP sharing procedure with the second AP before the start time of the TWT SP of the second AP, if the TWT of the second AP is a restricted TWT (R-TWT).

[0230] FIG. 19 is a diagram showing an example configuration of a station according to one embodiment of the present disclosure.

[0231] In FIG. 19, the station may include a processor (1901), a transceiver (1902), and a memory (1903). The processor (1901), the transceiver (1902), and the memory (1903) of the terminal may operate according to the method(s) described in the above-described embodiments of FIGS. 1 to 17 . However, the components of the station are not limited to the above-described examples. For example, the station may include more or fewer components than the above-described components. In addition, the processor (1901), the transceiver (1902), and the memory (1903) may be implemented in the form of at least one chip.

[0232] The transceiver (1902) is a general term for a receiver and a transmitter, and can transmit and receive signals with a terminal or other network entity through the transceiver (1902). At this time, the transmitted and received signals may include at least one of control information and data. To this end, the transceiver (1902) may include an RF transmitter that up-converts and amplifies the frequency of a transmitted signal, and an RF receiver that low-noise amplifies and frequency-converts the received signal. This is only one embodiment of the transceiver (1902), and the components of the transceiver (1902) are not limited to the RF transmitter and RF receiver. In addition, the transceiver (1902) can receive a signal and output it to the processor (1901), and transmit the signal output from the processor (1901) to another network entity through the network.

[0233] The memory (1903) can store programs and data necessary for the operation of the station according to at least one of the embodiments of FIGS. 1 to 17. In addition, the memory (1903) can store control information and / or data included in a signal acquired from the terminal. The memory (1903) can be configured as a storage medium or a combination of storage media, such as a ROM, a RAM, a hard disk, a CD-ROM, and a DVD.

[0234] The processor (1901) may control a series of processes so that the station can operate according to at least one of the embodiments of FIGS. 1 to 17. The processor (1901) may include at least one processor.

[0235] In the specific embodiments of the present disclosure described above, components included in the present disclosure are expressed singularly or plurally, depending on the specific embodiment presented. However, the singular or plural expressions are selected to suit the presented situation for convenience of explanation, and the present disclosure is not limited to singular or plural components. Components expressed in plural may be composed of singular elements, or components expressed in singular may be composed of plural elements.

[0236] While the detailed description of this disclosure has described specific embodiments, it should be understood that various modifications are possible without departing from the scope of this disclosure. Therefore, the scope of this disclosure should not be limited to the described embodiments, but should be defined not only by the scope of the claims described below, but also by equivalents thereof.

Claims

1. In the method of the first AP (access point) performing Wi-Fi communication, An operation of receiving a control frame (ICF) containing shared information of a transmission opportunity (TXOP) for coordinated time division multiple access (Co-TDMA) from a second AP; and Including an operation of allocating a TXOP section acquired by the second AP based on the shared information of the TXOP; The above first AP is a Co-TDMA shared AP and the above second AP is a Co-TDMA sharing AP. A method characterized in that the above control frame (ICF) further includes at least one shared AP identifier.

2. In paragraph 1, An operation of receiving TWT (target wake time) schedule information of the second AP broadcasted by the second AP; An operation of checking the TWT SP (service period) of the second AP based on the TWT schedule information of the second AP; and A method characterized by including an operation of obtaining the TXOP interval based on a time interval required for frame exchange of the first AP and the TWT SP of the second AP.

3. In paragraph 2, An operation of receiving TWT schedule information of the third AP broadcasted by the third AP; and Further comprising an operation of checking the TWT SP of the third AP based on the TWT schedule information of the third AP, A method characterized in that the TXOP period of the first AP is obtained based on the time period required for the frame exchange of the first AP, the TWT SP of the second AP, and the TWT SP of the third AP.

4. In paragraph 1, An operation of confirming that the interval between the end time of the time interval required for the frame exchange of the first AP and the start time of the TWT SP of the second AP is less than or equal to a set threshold value; and A method characterized in that it further includes an operation of determining to use the TWT SP of the second AP when acquiring the TXOP section of the first AP.

5. In paragraph 3, A method characterized in that the first BSS (basic service set) of the first AP, the second BSS of the second AP, and the third BSS of the third AP overlap each other.

6. In paragraph 3, A method further comprising broadcasting a control frame including a first point in time at which the first AP shares a TXOP with the second AP, and a second point in time at which the second AP shares a TXOP with the third AP.

7. In paragraph 6, An operation of determining the first point in time based on the start point of the TWT SP of the second AP; and A method further comprising an operation of determining the second point in time based on the average TWT SP time of the second AP and the start point of the TWT SP of the third AP.

8. In paragraph 3, A method further comprising broadcasting a control frame including a first point in time at which the first AP shares a TXOP with the second AP, and a second point in time at which the first AP shares a TXOP with the third AP.

9. In paragraph 8, A method characterized in that it further includes an operation of returning the TXOP from the second AP before the second time point.

10. In the second paragraph, the TWT schedule information of the second AP is A method characterized in that it includes an average TWT SP time of the second AP, information about traffic exchanged within the TWT SP of the second AP, and information indicating a priority of the traffic.

11. In paragraph 2, A method characterized in that it further includes an operation of performing a TXOP sharing procedure with the second AP before the start time of the TWT SP of the second AP, when the TWT of the second AP is R-TWT (restricted TWT).

12. In the first AP (access point) performing Wi-Fi communication, Transmitter and receiver; and comprising a control unit, wherein the control unit is: Receive a control frame (ICF) containing sharing information of a transmission opportunity (TXOP) for coordinated time division multiple access (Co-TDMA) from a second AP, Based on the shared information of the above TXOP, the TXOP section acquired by the second AP is allocated, The above first AP is a Co-TDMA shared AP and the above second AP is a Co-TDMA sharing AP. An AP characterized in that the above control frame (ICF) further includes at least one shared AP identifier.

13. In the 12th paragraph, the control unit, Receive the TWT (target wake time) schedule information of the second AP broadcasted by the second AP, Check the TWT SP (service period) of the second AP based on the TWT schedule information of the second AP, An AP characterized in that the TXOP interval is obtained based on the time interval required for frame exchange of the first AP and the TWT SP of the second AP.

14. In the 13th paragraph, the control unit, Receive the TWT schedule information of the third AP broadcasted by the third AP, Check the TWT SP of the third AP based on the TWT schedule information of the third AP, An AP characterized in that the TXOP period of the first AP is obtained based on the time period required for the frame exchange of the first AP, the TWT SP of the second AP, and the TWT SP of the third AP.

15. In the 13th paragraph, the control unit, Confirm that the interval between the end time of the time interval required for the frame exchange of the first AP and the start time of the TWT SP of the second AP is less than or equal to a set threshold value, An AP characterized in that it is determined to use the TWT SP of the second AP when acquiring the TXOP section of the first AP.

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