Method and apparatus for sharing dynamic transmission opportunity in wireless LAN system

Abstract

Disclosed are a method and an apparatus for dynamically sharing a transmission opportunity (TXOP) in a wireless LAN system. The method according to an embodiment of the present disclosure may comprise the steps of: a first station (STA) transmitting, to a second STA within a transmission opportunity (TXOP) duration of the second STA, a first frame including information indicating the presence of traffic to be transmitted from the first STA; and after transmitting the first frame, the first STA transmitting a second frame including the traffic to the second STA.

Description

Method and device for dynamic transmission opportunity sharing in a wireless LAN system

[0001] The present disclosure relates to a method and device for dynamically sharing a transmission opportunity (TXOP) in a wireless local area network (WLAN) system.

[0002] New technologies have been introduced for wireless local area networks (WLANs) to improve transmission rates, increase bandwidth, enhance reliability, reduce errors, and reduce latency. Among WLAN technologies, the IEEE (Institute of Electrical and Electronics Engineers) 802.11 series of standards can be referred to as Wi-Fi. For example, recently introduced technologies for WLANs include enhancements for Very High Throughput (VHT) in the 802.11ac standard and enhancements for High Efficiency (HE) in the IEEE 802.11ax standard.

[0003] To provide a more advanced wireless communication environment, improved technologies for Extremely High Throughput (EHT) are being discussed. For example, technologies for Multiple Input Multiple Output (MIMO), which supports increased bandwidth, efficient utilization of multiple bands, and increased spatial streams, and for coordination of multiple access points (APs), are being studied. In particular, various technologies are being studied to support low latency or real-time traffic. Furthermore, new technologies are being discussed to support ultra-high reliability (UHR), including improvements or extensions of EHT technology.

[0004] The technical problem of the present disclosure is to provide a method and device for sharing dynamic transmission opportunity (TXOP).

[0005] An additional technical challenge of the present disclosure is to provide a method and device for transmitting or receiving information for sharing a TXOP by a TXOP holder.

[0006] An additional technical problem of the present disclosure is to provide a method and device for transmitting or receiving information for sharing TXOP from a TXOP holder.

[0007] An additional technical problem of the present disclosure is to provide a method and device for transmitting or receiving information for TXOP recovery after TXOP sharing.

[0008] The technical problems to be achieved in the present disclosure are not limited to the technical problems mentioned above, and other technical problems not mentioned can be clearly understood by a person having ordinary skill in the technical field to which the present disclosure belongs from the description below.

[0009] A method according to one aspect of the present disclosure may include: transmitting, by a first station (STA), to a second STA, a first frame including information indicating the presence of traffic to be transmitted from the first STA within a transmit opportunity (TXOP) duration of the second STA; and, after transmitting the first frame, transmitting, by the first STA, to the second STA, a second frame including the traffic.

[0010] A method according to an additional aspect of the present disclosure may include: receiving, by a second station (STA), from a first STA, a first frame including information indicating the presence of traffic to be transmitted from the first STA within a transmit opportunity (TXOP) duration of the second STA; and receiving, by the second STA after receiving the first frame, a second frame including the traffic from the first STA.

[0011] According to the present disclosure, a method and device for sharing dynamic transmit opportunity (TXOP) can be provided.

[0012] According to the present disclosure, a method and device for transmitting or receiving information for sharing a TXOP by a TXOP holder can be provided.

[0013] According to the present disclosure, a method and device for transmitting or receiving information for sharing TXOP from a TXOP holder may be provided.

[0014] According to the present disclosure, a method and device for transmitting or receiving information for TXOP recovery after TXOP sharing can be provided.

[0015] The effects that can be obtained from the present disclosure are not limited to the effects mentioned above, and other effects that are not mentioned will be clearly understood by a person having ordinary skill in the art to which the present disclosure pertains from the description below.

[0016] The accompanying drawings, which are incorporated in and are part of the detailed description to aid in understanding the present disclosure, provide embodiments of the present disclosure and, together with the detailed description, describe the technical features of the present disclosure.

[0017] FIG. 1 illustrates a block diagram of a wireless communication device according to one embodiment of the present disclosure.

[0018] FIG. 2 is a diagram showing an exemplary structure of a wireless LAN system to which the present disclosure can be applied.

[0019] FIG. 3 is a diagram for explaining a link setup process to which the present disclosure can be applied.

[0020] FIG. 4 is a diagram for explaining a backoff process to which the present disclosure can be applied.

[0021] FIG. 5 is a diagram for explaining a CSMA / CA-based frame transmission operation to which the present disclosure can be applied.

[0022] FIG. 6 is a drawing for explaining an example of a frame structure used in a wireless LAN system to which the present disclosure can be applied.

[0023] FIG. 7 is a diagram illustrating examples of PPDUs defined in the IEEE 802.11 standard to which the present disclosure can be applied.

[0024] FIG. 8 is a diagram for explaining various transmission and reception techniques in a MAP environment to which the present disclosure can be applied.

[0025] Figure 9 shows examples of topologies of low-latency communication to which the present disclosure can be applied.

[0026] FIG. 10 is a diagram illustrating an example of the operation of the first STA according to the present disclosure.

[0027] FIG. 11 is a diagram illustrating an example of the operation of a second STA according to the present disclosure.

[0028] FIG. 12 is a diagram showing examples of TXOP sharing instructions according to the present disclosure.

[0029] FIG. 13 is a diagram showing an exemplary format of a BA frame to which the present disclosure can be applied.

[0030] FIG. 14 is a diagram showing examples of transmission operations through TXOP sharing according to the present disclosure.

[0031] FIG. 15 is a diagram showing examples of TXOP shared recovery according to the present disclosure.

[0032] Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. The detailed description set forth below, together with the accompanying drawings, is intended to explain exemplary embodiments of the present disclosure and is not intended to represent the only embodiments in which the present disclosure may be practiced. The following detailed description includes specific details to provide a thorough understanding of the present disclosure. However, one of ordinary skill in the art will appreciate that the present disclosure may be practiced without these specific details.

[0033] In some cases, to avoid obscuring the concepts of the present disclosure, known structures and devices may be omitted or illustrated in block diagram form focusing on the core functions of each structure and device.

[0034] In the present disclosure, when a component is said to be "connected," "coupled," or "connected" to another component, this may include not only a direct connection but also an indirect connection in which another component exists between them. Furthermore, the terms "comprises" or "has" in the present disclosure specify the presence of the mentioned features, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof.

[0035] In this disclosure, terms such as “first,” “second,” etc. are used only to distinguish one component from another and are not used to limit the components, and do not limit the order or importance between the components unless specifically stated otherwise. Accordingly, within the scope of this disclosure, a first component in one embodiment may be referred to as a second component in another embodiment, and similarly, a second component in one embodiment may be referred to as a first component in another embodiment.

[0036] The terminology used herein is for the purpose of describing particular embodiments and is not intended to limit the scope of the claims. As used in the description of the embodiments and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly dictates otherwise. The term "and / or" as used herein may refer to any one of the associated enumerated items, or is meant to refer to and encompass any and all possible combinations of two or more of them. Furthermore, the use of " / " between words in this disclosure has the same meaning as "and / or" unless otherwise stated.

[0037] The examples of the present disclosure can be applied to various wireless communication systems. For example, the examples of the present disclosure can be applied to a wireless LAN system. For example, the examples of the present disclosure can be applied to a wireless LAN based on the IEEE 802.11a / g / n / ac / ax / be standards. Furthermore, the examples of the present disclosure can be applied to a wireless LAN based on the newly proposed IEEE 802.11bn (or UHR) standard. Additionally, the examples of the present disclosure can be applied to a wireless LAN based on the next-generation standard after IEEE 802.11bn. Furthermore, the examples of the present disclosure can be applied to a cellular wireless communication system. For example, the examples of the present disclosure can be applied to a cellular wireless communication system based on the LTE (Long Term Evolution) series of technologies and the 5G NR (New Radio) series of technologies of the 3rd Generation Partnership Project (3GPP) standard.

[0038] Below, technical features to which examples of the present disclosure can be applied are described.

[0039] FIG. 1 illustrates a block diagram of a wireless communication device according to one embodiment of the present disclosure.

[0040] The first device (100) and the second device (200) illustrated in FIG. 1 may be replaced with various terms such as a terminal, a wireless device, a WTRU (Wireless Transmit Receive Unit), a UE (User Equipment), an MS (Mobile Station), a UT (user terminal), an MSS (Mobile Subscriber Station), an MSS (Mobile Subscriber Unit), an SS (Subscriber Station), an AMS (Advanced Mobile Station), a WT (Wireless terminal), or simply a user. In addition, the first device (100) and the second device (200) may be replaced with various terms such as an access point (AP), a BS (Base Station), a fixed station, a Node B, a BTS (Base Transceiver System), a network, an AI (Artificial Intelligence) system, an RSU (road side unit), a repeater, a router, a relay, a gateway, etc.

[0041] The devices (100, 200) illustrated in FIG. 1 may also be referred to as stations (STAs). For example, the devices (100, 200) illustrated in FIG. 1 may be referred to by various terms such as transmitting device, receiving device, transmitting STA, and receiving STA. For example, the STAs (110, 200) may perform an AP (access point) role or a non-AP role. That is, in the present disclosure, the STAs (110, 200) may perform the functions of an AP and / or a non-AP. When the STAs (110, 200) perform an AP function, they may simply be referred to as APs, and when the STAs (110, 200) perform a non-AP function, they may simply be referred to as STAs. In addition, in the present disclosure, the APs may also be referred to as AP STAs.

[0042] Referring to FIG. 1, the first device (100) and the second device (200) can transmit and receive wireless signals through various wireless LAN technologies (e.g., IEEE 802.11 series). The first device (100) and the second device (200) can include interfaces for a medium access control (MAC) layer and a physical layer (PHY) that follow the provisions of the IEEE 802.11 standard.

[0043] In addition, the first device (100) and the second device (200) may additionally support various communication standards (e.g., 3GPP LTE series, 5G NR series standards, etc.) other than wireless LAN technology. In addition, the device of the present disclosure may be implemented as various devices such as a mobile phone, a vehicle, a personal computer, an AR (Augmented Reality) device, a VR (Virtual Reality) device, etc. In addition, the STA of the present specification may support various communication services such as voice calls, video calls, data communications, autonomous driving, MTC (Machine-Type Communication), M2M (Machine-to-Machine), D2D (Device-to-Device), and IoT (Internet-of-Things).

[0044] A first device (100) includes one or more processors (102) and one or more memories (104), and may further include one or more transceivers (106) and / or one or more antennas (108). The processor (102) controls the memories (104) and / or the transceivers (106), and may be configured to implement the descriptions, functions, procedures, proposals, methods, and / or operational flowcharts disclosed in the present disclosure. For example, the processor (102) may process information in the memories (104) to generate first information / signals, and then transmit a wireless signal including the first information / signals via the transceivers (106). Furthermore, the processor (102) may receive a wireless signal including second information / signals via the transceivers (106), and then store information obtained from signal processing of the second information / signals in the memory (104). The memory (104) may be connected to the processor (102) and may store various information related to the operation of the processor (102). For example, the memory (104) may perform some or all of the processes controlled by the processor (102), or may store software code including instructions for performing the descriptions, functions, procedures, proposals, methods, and / or operation flowcharts disclosed in the present disclosure. Here, the processor (102) and the memory (104) may be part of a communication modem / circuit / chip designed to implement a wireless LAN technology (e.g., IEEE 802.11 series). The transceiver (106) may be connected to the processor (102) and may transmit and / or receive wireless signals via one or more antennas (108). The transceiver (106) may include a transmitter and / or a receiver. The transceiver (106) may be used interchangeably with an RF (Radio Frequency) unit. In the present disclosure, a device may also mean a communication modem / circuit / chip.

[0045] The second device (200) includes one or more processors (202), one or more memories (204), and may further include one or more transceivers (206) and / or one or more antennas (208). The processor (202) controls the memories (204) and / or the transceivers (206), and may be configured to implement the descriptions, functions, procedures, proposals, methods, and / or operational flowcharts disclosed in the present disclosure. For example, the processor (202) may process information in the memory (204) to generate third information / signals, and then transmit a wireless signal including the third information / signals via the transceivers (206). Furthermore, the processor (202) may receive a wireless signal including fourth information / signals via the transceivers (206), and then store information obtained from signal processing of the fourth information / signals in the memory (204). The memory (204) may be connected to the processor (202) and may store various information related to the operation of the processor (202). For example, the memory (204) may perform some or all of the processes controlled by the processor (202), or may store software code including instructions for performing the descriptions, functions, procedures, proposals, methods, and / or operation flowcharts disclosed in the present disclosure. Here, the processor (202) and the memory (204) may be part of a communication modem / circuit / chip designed to implement a wireless LAN technology (e.g., IEEE 802.11 series). The transceiver (206) may be connected to the processor (202) and may transmit and / or receive wireless signals via one or more antennas (208). The transceiver (206) may include a transmitter and / or a receiver. The transceiver (206) may be used interchangeably with an RF unit. In the present disclosure, a device may also mean a communication modem / circuit / chip.

[0046] Hereinafter, the hardware elements of the device (100, 200) will be described in more detail. Although not limited thereto, one or more protocol layers may be implemented by one or more processors (102, 202). For example, one or more processors (102, 202) may implement one or more layers (e.g., functional layers such as PHY, MAC). One or more processors (102, 202) may generate one or more Protocol Data Units (PDUs) and / or one or more Service Data Units (SDUs) according to the descriptions, functions, procedures, proposals, methods, and / or operational flowcharts disclosed in the present disclosure. One or more processors (102, 202) may generate messages, control information, data, or information according to the descriptions, functions, procedures, proposals, methods, and / or operational flowcharts disclosed in the present disclosure. One or more processors (102, 202) can generate signals (e.g., baseband signals) including PDUs, SDUs, messages, control information, data or information according to the functions, procedures, proposals and / or methods disclosed in the present disclosure, and provide the signals to one or more transceivers (106, 206). One or more processors (102, 202) can receive signals (e.g., baseband signals) from one or more transceivers (106, 206) and obtain PDUs, SDUs, messages, control information, data or information according to the descriptions, functions, procedures, proposals, methods and / or operational flowcharts disclosed in the present disclosure.

[0047] One or more processors (102, 202) may be referred to as a controller, a microcontroller, a microprocessor, or a microcomputer. One or more processors (102, 202) may be implemented by hardware, firmware, software, or a combination thereof. For example, one or more Application Specific Integrated Circuits (ASICs), one or more Digital Signal Processors (DSPs), one or more Digital Signal Processing Devices (DSPDs), one or more Programmable Logic Devices (PLDs), or one or more Field Programmable Gate Arrays (FPGAs) may be included in one or more processors (102, 202). The descriptions, functions, procedures, proposals, methods, and / or operational flowcharts disclosed in this disclosure may be implemented using firmware or software, and the firmware or software may be implemented to include modules, procedures, functions, etc. The descriptions, functions, procedures, proposals, methods and / or operation flowcharts disclosed in this disclosure may be implemented using firmware or software configured to perform one or more processors (102, 202) or stored in one or more memories (104, 204) and driven by one or more processors (102, 202). The descriptions, functions, procedures, proposals, methods and / or operation flowcharts disclosed in this disclosure may be implemented using firmware or software in the form of codes, instructions and / or sets of instructions.

[0048] One or more memories (104, 204) may be coupled to one or more processors (102, 202) and may store various forms of data, signals, messages, information, programs, codes, instructions, and / or commands. The one or more memories (104, 204) may be configured as ROM, RAM, EPROM, flash memory, hard drives, registers, cache memory, computer-readable storage media, and / or combinations thereof. The one or more memories (104, 204) may be located internally and / or externally to the one or more processors (102, 202). Additionally, the one or more memories (104, 204) may be coupled to the one or more processors (102, 202) via various technologies, such as wired or wireless connections.

[0049] One or more transceivers (106, 206) can transmit user data, control information, wireless signals / channels, etc., as mentioned in the methods and / or flowcharts of the present disclosure, to one or more other devices. One or more transceivers (106, 206) can receive user data, control information, wireless signals / channels, etc., as mentioned in the descriptions, functions, procedures, proposals, methods and / or flowcharts of the present disclosure, from one or more other devices. For example, one or more transceivers (106, 206) can be coupled to one or more processors (102, 202) and can transmit and receive wireless signals. For example, one or more processors (102, 202) can control one or more transceivers (106, 206) to transmit user data, control information, or wireless signals to one or more other devices. Additionally, one or more processors (102, 202) may control one or more transceivers (106, 206) to receive user data, control information, or wireless signals from one or more other devices. Additionally, one or more transceivers (106, 206) may be coupled to one or more antennas (108, 208), and one or more transceivers (106, 206) may be configured to transmit and receive user data, control information, wireless signals / channels, or the like, as referred to in the descriptions, functions, procedures, proposals, methods, and / or operational flowcharts disclosed in the present disclosure, via one or more antennas (108, 208). In the present disclosure, one or more antennas may be multiple physical antennas or multiple logical antennas (e.g., antenna ports). One or more transceivers (106, 206) can convert received user data, control information, wireless signals / channels, etc. from RF band signals to baseband signals in order to process the received user data, control information, wireless signals / channels, etc. using one or more processors (102, 202).One or more transceivers (106, 206) may convert user data, control information, wireless signals / channels, etc. processed by one or more processors (102, 202) from baseband signals to RF band signals. For this purpose, one or more transceivers (106, 206) may include an (analog) oscillator and / or filter.

[0050] For example, one of the STAs (100, 200) may perform the intended operation of an AP, and the other of the STAs (100, 200) may perform the intended operation of a non-AP STA. For example, the transceivers (106, 206) of FIG. 1 may perform transmission and reception operations of signals (e.g., packets or PPDUs (Physical layer Protocol Data Units) according to IEEE 802.11a / b / g / n / ac / ax / be / bn, etc.). In addition, in the present disclosure, operations in which various STAs generate transmission and reception signals or perform data processing or calculations in advance for transmission and reception signals may be performed in the processors (102, 202) 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 field (SIG (signal), STF (short training field), LTF (long training field), Data, etc.) included in a PPDU, 2) an operation for determining / configuring / obtaining time resources or frequency resources (e.g., subcarrier resources) used for a field (SIG, STF, LTF, Data, etc.) 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 field (SIG, STF, LTF, Data, etc.) 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 (104, 204) of FIG. 1.

[0051] Hereinafter, downlink (DL) refers to a link for communication from an AP STA to a non-AP STA, and downlink PPDUs / packets / signals, etc. can be transmitted and received through the downlink. In downlink communication, the transmitter may be part of an AP STA, and the receiver may be part of a non-AP STA. Uplink (UL) refers to a link for communication from a non-AP STA to an AP STA, and uplink PPDUs / packets / signals, etc. can be transmitted and received through the uplink. In uplink communication, the transmitter may be part of a non-AP STA, and the receiver may be part of an AP STA.

[0052] FIG. 2 is a diagram showing an exemplary structure of a wireless LAN system to which the present disclosure can be applied.

[0053] The structure of a wireless LAN system can be composed of multiple components. Through the interaction of multiple components, a wireless LAN that supports transparent STA mobility to the upper layer can be provided. A Basic Service Set (BSS) corresponds to a basic building block of a wireless LAN. FIG. 2 illustrates, by way of example, the existence of two BSSs (BSS1 and BSS2) and the inclusion of two STAs as members of each BSS (STA1 and STA2 are included in BSS1, and STA3 and STA4 are included in BSS2). The oval representing a BSS in FIG. 2 can also be understood as representing a coverage area in which STAs included in the corresponding BSS maintain communication. This area can be referred to as a Basic Service Area (BSA). When an STA moves outside of a BSA, it cannot directly communicate with other STAs within the BSA.

[0054] If we do not consider the DS illustrated in Figure 2, the most basic type of BSS in a wireless LAN is an Independent BSS (IBSS). For example, an IBSS can have a minimal form consisting of only two STAs. For example, assuming other components are omitted, BSS1 consisting of only STA1 and STA2, or BSS2 consisting of only STA3 and STA4, can be representative examples of an IBSS, respectively. Such a configuration is possible when the STAs can communicate directly without an AP. Furthermore, in this type of WLAN, a LAN can be configured when needed rather than being planned in advance, and this can be called an ad-hoc network. Since an IBSS does not include an AP, there is no centralized management entity. That is, in an IBSS, STAs are managed in a distributed manner. In IBSS, all STAs can be mobile STAs, and access to distributed systems (DS) is not permitted, forming a self-contained network.

[0055] An STA's membership in a BSS can dynamically change, for example, when an STA is turned on or off, or when an STA enters or leaves a BSS area. To become a member of a BSS, an STA can join the BSS using a synchronization process. To access all services in the BSS infrastructure, an STA must be associated with the BSS. This association can be dynamically established and may involve the use of a Distribution System Service (DSS).

[0056] In a wireless LAN, the direct STA-to-STA distance can be limited by PHY performance. While this distance limit may be sufficient in some cases, communication between STAs over longer distances may be required in other cases. To support extended coverage, a distributed system (DS) can be configured.

[0057] DS refers to a structure in which BSSs are interconnected. Specifically, a BSS may exist as an extended component of a network composed of multiple BSSs, as illustrated in Figure 2. DS is a logical concept and can be specified by the characteristics of a distributed system medium (DSM). In this regard, the Wireless Medium (WM) and DSM can be logically distinguished. Each logical medium is used for a different purpose and by different components. These media are neither limited to being identical nor limited to being different. This logical difference between multiple media explains the flexibility of the WLAN architecture (DS architecture or other network architectures). In other words, the WLAN architecture can be implemented in various ways, and the physical characteristics of each implementation can independently specify the WLAN architecture.

[0058] A DS can support mobile devices by providing seamless integration of multiple BSSs and the logical services necessary to handle addresses to destinations. Additionally, a DS may further include a component called a portal, which acts as a bridge for connecting wireless LANs to other networks (e.g., IEEE 802.X).

[0059] An AP is an entity that enables access to a DS through a WM for associated non-AP STAs and also has the functionality of an STA. Data movement between a BSS and a DS can be performed through an AP. For example, STA2 and STA3 illustrated in FIG. 2 have the functionality of an STA and provide the function of allowing associated non-AP STAs (STA1 and STA4) to access the DS. In addition, since all APs are basically STAs, all APs are addressable entities. The address used by an AP for communication on a WM and the address used by an AP for communication on a DSM do not necessarily have to be the same. A BSS consisting of an AP and one or more STAs can be referred to as an infrastructure BSS.

[0060] Data transmitted from one of the STA(s) associated with an AP to the STA address of that AP is always received on an uncontrolled port and can be processed by an IEEE 802.1X port access entity. In addition, if the controlled port is authenticated, the transmitted data (or frame) can be forwarded to the DS.

[0061] In addition to the structure of the DS described above, an extended service set (ESS) may be established to provide wider coverage.

[0062] An ESS is a network of arbitrary size and complexity, consisting of DSs and BSSs. An ESS may correspond to a set of BSSs connected to a DS. However, an ESS does not include a DS. An ESS network is characterized by appearing as an IBSS at the Logical Link Control (LLC) layer. STAs within an ESS can communicate with each other, and mobile STAs can move from one BSS to another (within the same ESS) transparently to the LLC. APs within an ESS may have the same SSID (service set identification). The SSID is distinct from the BSSID, which is the identifier of the BSS.

[0063] In a wireless LAN system, no assumptions are made about the relative physical locations of BSSs, and all of the following configurations are possible: BSSs can be partially overlapping, which is commonly used to provide continuous coverage. BSSs can also be physically disconnected, and there is no logical distance limit between them. BSSs can also be physically co-located, which can be used to provide redundancy. Furthermore, one (or more) IBSS or ESS networks can physically co-exist with one (or more) ESS networks. This can occur in cases where an ad-hoc network operates at the same location as an ESS network, where physically overlapping wireless networks are configured by different organizations, or where two or more different access and security policies are required at the same location.

[0064] FIG. 3 is a diagram for explaining a link setup process to which the present disclosure can be applied.

[0065] For an STA to set up a link and transmit and receive data on a network, it must first discover the network, perform authentication, establish an association, and complete security authentication procedures. The link setup process can also be referred to as the session initiation process or session setup process. Furthermore, the discovery, authentication, association, and security setup processes of the link setup process can be collectively referred to as the association process.

[0066] In step S310, the STA may perform a network discovery operation. This network discovery operation may include scanning operations by the STA. That is, for the STA to access a network, it must search for available networks. Before joining a wireless network, the STA must identify compatible networks. The process of identifying networks in a specific area is called scanning.

[0067] Scanning methods include active scanning and passive scanning. Figure 3 illustrates a network discovery operation including an active scanning process as an example. In active scanning, an STA performing scanning transmits a probe request frame to discover any APs in the vicinity while moving between channels and waits for a response. The responder transmits a probe response frame in response to the STA that transmitted 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 the BSS, the AP transmits the beacon frame, so the AP becomes the responder. In the IBSS, the STAs within the IBSS take turns transmitting beacon frames, so the responder is not fixed. 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.

[0068] Although not shown in Figure 3, the scanning operation can also be performed in a passive scanning manner. In passive scanning, the STA performing the scanning moves between channels and waits for a beacon frame. A beacon frame is one of the management frames defined in IEEE 802.11. It announces the existence of a wireless network and is periodically transmitted so that the STA performing the scanning can find the wireless network and participate in the wireless network. In the BSS, the AP performs the role of periodically transmitting the beacon frame, and in the IBSS, the STAs within the IBSS take turns transmitting the beacon frame. When the STA performing the scanning 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. The STA receiving the beacon frame stores the BSS-related information included in the received beacon frame and moves to the next channel to perform scanning on the next channel in the same manner. Comparing active scanning and passive scanning, active scanning has the advantage of lower delay and power consumption than passive scanning.

[0069] After the STA discovers the network, an authentication process may be performed in 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.

[0070] The authentication process involves the STA sending an authentication request frame to the AP, and the AP responding by sending an authentication response frame to the STA. The authentication frame used for the authentication request / response corresponds to a management frame.

[0071] 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. These are just some examples of information that may be included in an authentication request / response frame, and may be replaced with other information or include additional information.

[0072] An STA can send 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.

[0073] After the STA is successfully authenticated, an association process may be performed in step S330. The association process includes a process in which the STA transmits an association request frame to the AP, and in response, the AP transmits an association response frame to the STA.

[0074] For example, the association request frame may include information about various capabilities, a beacon listen interval, a service set identifier (SSID), supported rates, supported channels, RSN, a mobility domain, supported operating classes, a Traffic Indication Map Broadcast request, interworking service capabilities, etc. For example, the association response frame may include information about various capabilities, a status code, an Association ID (AID), supported rates, an Enhanced Distributed Channel Access (EDCA) parameter set, a Received Channel Power Indicator (RCPI), a Received Signal to Noise Indicator (RSNI), a mobility domain, a timeout interval (e.g., an association comeback time), overlapping BSS scan parameters, a TIM broadcast response, a Quality of Service (QoS) map, etc. These are just some examples of information that may be included in a combined request / response frame, and may be replaced with other information or include additional information.

[0075] After the STA successfully joins the network, a security setup process may be performed in step S340. The security setup process in step S340 may be referred to as an authentication process through a Robust Security Network Association (RSNA) request / response, the authentication process in step S320 may be referred to as a first authentication process, and the security setup process in step S340 may also be referred to simply as an authentication process.

[0076] The security setup process of step S340 may include, for example, a process of establishing a private key through a four-way handshaking using an Extensible Authentication Protocol over LAN (EAPOL) frame. Furthermore, the security setup process may be performed according to a security method not defined in the IEEE 802.11 standard.

[0077] FIG. 4 is a diagram for explaining a backoff process to which the present disclosure can be applied.

[0078] In wireless LAN systems, the basic access mechanism of MAC (Medium Access Control) is Carrier Sense Multiple Access with Collision Avoidance (CSMA / CA). The CSMA / CA mechanism, also known as the Distributed Coordination Function (DCF) of the IEEE 802.11 MAC, essentially employs a "listen before talk" access mechanism. According to this type of access mechanism, the AP and / or STA may perform a Clear Channel Assessment (CCA) to sense the wireless channel or medium for a predetermined time period (e.g., a DCF Inter-Frame Space (DIFS)) before starting transmission. If the sensing result determines that the medium is in an idle state, the AP and / or STA may start transmitting frames through the medium. On the other hand, if the medium is detected to be occupied or busy, the AP and / or STA may not start its own transmission, but may wait for a delay period (e.g., a random backoff period) for medium access before attempting to transmit frames. By applying a random backoff period, multiple STAs are expected to attempt to transmit frames after waiting for different periods of time, thereby minimizing collisions.

[0079] In addition, the IEEE 802.11 MAC protocol provides the Hybrid Coordination Function (HCF). The HCF is based on the DCF and the Point Coordination Function (PCF). The PCF is a polling-based synchronous access method that periodically polls all receiving APs and / or STAs to ensure that they receive data frames. In addition, the HCF has the Enhanced Distributed Channel Access (EDCA) and the HCF Controlled Channel Access (HCCA). The EDCA is a contention-based access method for a provider to provide data frames to multiple users, while the HCCA uses a non-contention-based channel access method that utilizes a polling mechanism. In addition, the HCF includes a medium access mechanism to improve the Quality of Service (QoS) of the wireless LAN, and can transmit QoS data in both the Contention Period (CP) and the Contention Free Period (CFP).

[0080] Referring to Fig. 4, an operation based on a random backoff period is described. When a medium that was occupied / busy changes to an idle state, multiple STAs can attempt to transmit data (or frames). To minimize collisions, each STA can select a random backoff count, wait for the corresponding slot time, and then attempt transmission. The random backoff count has a pseudo-random integer value and can be determined as one of the values ​​in the range of 0 to CW. Here, CW is a contention window parameter value. The CW parameter is given an initial value of CWmin, but can take a doubled value in case of transmission failure (e.g., when an ACK for a transmitted frame is not received). When the CW parameter value becomes CWmax, data transmission can be attempted while maintaining the CWmax value until data transmission is successful, and if data transmission is successful, it is reset to the CWmin value. The CW, CWmin, and CWmax values ​​are 2. n It is desirable to set it to -1 (n=0, 1, 2, ...).

[0081] Once the random backoff process begins, the STA continues to monitor the medium while counting down the backoff slots according to the determined backoff count value. If the medium is monitored as occupied, the countdown stops and waits. When the medium becomes idle, the remaining countdown resumes.

[0082] In the example of FIG. 4, when a packet to be transmitted reaches the MAC of STA3, STA3 can immediately transmit a frame if it confirms that the medium is idle for DIFS. The remaining STAs monitor the medium for occupied / busy states and wait. In the meantime, data to be transmitted may also occur in each of STA1, STA2, and STA5, and each STA can count down the backoff slot according to a random backoff count value selected by each STA after waiting for DIFS if the medium is monitored as idle. Assume that STA2 selects the smallest backoff count value and STA1 selects the largest backoff count value. In other words, this example shows a case where the remaining backoff time of STA5 is shorter than the remaining backoff time of STA1 when STA2 finishes the backoff count and starts frame transmission. STA1 and STA5 briefly stop counting down and wait while STA2 occupies the medium. When STA2's occupation ends and the medium becomes idle again, STA1 and STA5 wait for DIFS and then resume the backoff count that they had stopped. That is, they can start transmitting frames after counting down the remaining backoff slots equal to the remaining backoff time. Since STA5's remaining backoff time is shorter than STA1's, STA5 starts transmitting frames. While STA2 occupies the medium, STA4 may also have data to transmit. From STA4's perspective, when the medium becomes idle, it waits for DIFS, counts down according to its selected random backoff count value, and then starts transmitting frames. In the example of Figure 4, the remaining backoff time of STA5 coincidentally matches the random backoff count value of STA4, in which case a collision may occur between STA4 and STA5. If a collision occurs, neither STA4 nor STA5 will receive an ACK, resulting in a failure in data transmission.In this case, STA4 and STA5 can select a random backoff count value and perform a countdown after doubling the CW value. STA1 waits while the medium is occupied by transmissions from STA4 and STA5, and when the medium becomes idle, it waits for DIFS and can start transmitting frames after the remaining backoff time elapses.

[0083] As in the example of Fig. 4, a data frame is a frame used for transmitting data forwarded to a higher layer, and can be transmitted after a backoff performed after DIFS elapses from when the medium becomes idle. Additionally, a management frame is a frame used for exchanging management information that is not forwarded to a higher layer, and is transmitted after a backoff performed after an IFS elapses, such as DIFS or PIFS (Point coordination function IFS). Subtype frames of a management frame include a beacon, an association request / response, a re-association request / response, a probe request / response, and an authentication request / response. A control frame is a frame used to control access to the medium. The subtype frames of the control frame include Request-To-Send (RTS), Clear-To-Send (CTS), Acknowledgment (ACK), Power Save-Poll (PS-Poll), Block ACK (BlockAck), Block ACK Request (BlockACKReq), Null Data Packet Announcement (NDP), and Trigger. If the control frame is not a response frame to the previous frame, it is transmitted after a backoff performed after the DIFS (Direct Inverse Frame Stop) has elapsed, and if it is a response frame to the previous frame, it is transmitted without a backoff performed after the SIFS (short IFS). The type and subtype of the frame can be identified by the type field and subtype field in the Frame Control (FC) field.

[0084] A QoS (Quality of Service) STA can transmit a frame after a backoff performed after the AIFS (arbitration IFS) for the access category (AC) to which the frame belongs, i.e., AIFS[i] (where i is a value determined by the AC), has elapsed. Here, the frames for which AIFS[i] can be used can be data frames, management frames, and also control frames that are not response frames.

[0085] FIG. 5 is a diagram for explaining a CSMA / CA-based frame transmission operation to which the present disclosure can be applied.

[0086] As mentioned above, the CSMA / CA mechanism includes virtual carrier sensing in addition to physical carrier sensing, in which STAs directly sense the medium. Virtual carrier sensing is intended to address potential issues in medium access, such as the hidden node problem. For virtual carrier sensing, the MAC of an STA can utilize a Network Allocation Vector (NAV). The NAV is a value that an STA that is currently using or has the right to use the medium indicates to other STAs the remaining time until the medium becomes available. Therefore, the value set as NAV corresponds to the period during which the STA transmitting the frame is scheduled to use the medium, and an STA receiving the NAV value is prohibited from accessing the medium during that period. For example, the NAV can be set based on the value of the "duration" field in the MAC header of the frame.

[0087] In the example of FIG. 5, it is assumed that STA1 wants to transmit data to STA2, and STA3 is in a position to overhear some or all of the frames transmitted and received between STA1 and STA2.

[0088] In order to reduce the possibility of collisions in transmissions of multiple STAs in a CSMA / CA-based frame transmission operation, a mechanism using RTS / CTS frames may be applied. In the example of FIG. 5, while STA1 is transmitting, STA3 may determine that the medium is idle based on carrier sensing results. That is, STA1 may correspond to a hidden node for STA3. Alternatively, in the example of FIG. 5, while STA2 is transmitting, STA3 may determine that the medium is idle based on carrier sensing results. That is, STA2 may correspond to a hidden node for STA3. By exchanging RTS / CTS frames before performing data transmission and reception between STA1 and STA2, STAs outside the transmission range of either STA1 or STA2, or STAs outside the carrier sensing range for transmissions from STA1 or STA3, may not attempt to occupy the channel during data transmission and reception between STA1 and STA2.

[0089] Specifically, STA1 can determine whether a channel is occupied through carrier sensing. In terms of physical carrier sensing, STA1 can determine channel occupancy idleness based on the energy level or signal correlation detected in the channel. Furthermore, in terms of virtual carrier sensing, STA1 can determine the channel occupancy status using a network allocation vector (NAV) timer.

[0090] STA1 can transmit an RTS frame to STA2 after performing a backoff if the channel is idle during the DIFS. STA2 can transmit a CTS frame, which is a response to the RTS frame, to STA1 after an SIFS if it receives the RTS frame.

[0091] If STA3 cannot overhear a CTS frame from STA2 but can overhear an RTS frame from STA1, STA3 can use the duration information contained in the RTS frame to set a NAV timer for the subsequent consecutively transmitted frame transmission period (e.g., SIFS + CTS frame + SIFS + data frame + SIFS + ACK frame). Alternatively, if STA3 cannot overhear an RTS frame from STA1 but can overhear a CTS frame from STA2, STA3 can use the duration information contained in the CTS frame to set a NAV timer for the subsequent consecutively transmitted frame transmission period (e.g., SIFS + data frame + SIFS + ACK frame). That is, if STA3 can overhear one or more of the RTS or CTS frames from one or more of STA1 or STA2, it can set a NAV accordingly. If STA3 receives a new frame before the NAV timer expires, it can update the NAV timer using the duration information contained in the new frame. STA3 does not attempt channel access until the NAV timer expires.

[0092] If STA1 receives a CTS frame from STA2, it can transmit a data frame to STA2 after SIFS from the time when the CTS frame is completely received. If STA2 successfully receives the data frame, it can transmit an ACK frame in response to the data frame to STA1 after SIFS. STA3 can determine whether the channel is in use through carrier sensing if the NAV timer expires. If STA3 determines that the channel is not in use by another terminal during the DIFS after the NAV timer expires, it can attempt channel access after a contention window (CW) based on a random backoff has elapsed.

[0093] FIG. 6 is a drawing for explaining an example of a frame structure used in a wireless LAN system to which the present disclosure can be applied.

[0094] The PHY layer can prepare an MPDU (MAC PDU) to be transmitted based on an instruction or primitive (meaning a set of instructions or parameters) from the MAC layer. For example, when a command requesting the start of transmission of the PHY layer is received from the MAC layer, the PHY layer can switch to transmission mode and transmit the information (e.g., data) provided by the MAC layer in the form of a frame. In addition, when the PHY layer detects a valid preamble of the received frame, it monitors the header of the preamble and sends a command to the MAC layer notifying the start of reception of the PHY layer.

[0095] In this way, information transmission / reception in a wireless LAN system is done in the form of frames, and for this purpose, the PHY layer Protocol Data Unit (PPDU) format is defined.

[0096] A basic PPDU may include a Short Training Field (STF), a Long Training Field (LTF), a SIGNAL (SIG) field, and a Data field. The most basic (e.g., non-HT (High Throughput) as illustrated in FIG. 7) PPDU format may consist of only the Legacy-STF (L-STF), Legacy-LTF (L-LTF), Legacy-SIG (L-SIG) fields, and a Data field. Additionally, depending on the type of PPDU format (e.g., HT-mixed format PPDU, HT-greenfield format PPDU, VHT (Very High Throughput) PPDU, etc.), additional (or different types of) RL-SIG, U-SIG, non-legacy SIG field, non-legacy STF, non-legacy LTF, (i.e., xx-SIG, xx-STF, xx-LTF (e.g., xx is HT, VHT, HE, EHT, etc.)) may be included between the L-SIG field and the data field. More specific details are described below with reference to FIG. 7.

[0097] STF is a signal for signal detection, AGC (Automatic Gain Control), diversity selection, and precise time synchronization, while LTF is a signal for channel estimation, frequency error estimation, etc. STF and LTF can be said to be signals for synchronization and channel estimation of the OFDM physical layer.

[0098] The SIG field may include various information related to PPDU transmission and reception. For example, the L-SIG field may consist of 24 bits and may include a 4-bit Rate field, a 1-bit Reserved bit, a 12-bit Length field, a 1-bit Parity field, and a 6-bit Tail field. The RATE field may include information about the modulation and coding rate of data. 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, for a non-HT, HT, VHT, or EHT PPDU, the value of the Length field may be determined as a multiple of 3. For example, for HE PPDU, the value of the Length field can be determined as a multiple of 3 + 1 or a multiple of 3 + 2.

[0099] The data field may include a SERVICE field, a Physical layer Service Data Unit (PSDU), a PPDU TAIL bit, and, if necessary, padding bits. Some bits of the SERVICE field may be used to synchronize the descrambler at the receiving end. The PSDU corresponds to a MAC PDU defined at the MAC layer and may contain data generated / used by upper layers. The PPDU TAIL bit may be used to return the encoder to a 0 state. The padding bit may be used to adjust the length of the data field to a predetermined unit.

[0100] MAC PDUs are defined according to various MAC frame formats, and a basic MAC frame consists of a MAC header, a frame body, and a Frame Check Sequence (FCS). A MAC frame is composed of MAC PDUs and can be transmitted / received through the PSDU in the data portion of the PPDU format.

[0101] The MAC header includes a Frame Control field, a Duration / ID field, an Address field, etc. The Frame Control field may include control information required for frame transmission / reception. The Duration / ID field may be set to a time for transmitting the corresponding frame, etc. The Address subfields may indicate the receiver address, transmitter address, destination address, and source address of the frame, and some Address subfields may be omitted. For specific details of each subfield of the MAC header, including the Sequence Control, QoS Control, and HT Control subfields, refer to the IEEE 802.11 standard document.

[0102] The Null-Data PPDU (NDP) format refers to a PPDU format that does not include a data field. In other words, NDP refers to a frame format that includes a PPDU preamble (i.e., L-STF, L-LTF, L-SIG fields, and, if additionally present, non-legacy SIG, non-legacy STF, and non-legacy LTF) in the general PPDU format, and does not include the remaining part (i.e., data field).

[0103] FIG. 7 is a diagram illustrating examples of PPDUs defined in the IEEE 802.11 standard to which the present disclosure can be applied.

[0104] Standards such as IEEE 802.11a / g / n / ac / ax use various PPDU formats. The basic PPDU format (IEEE 802.11a / g) includes L-LTF, L-STF, L-SIG, and Data fields. The basic PPDU format can also be referred to as the non-HT PPDU format (Fig. 7(a)).

[0105] The HT PPDU format (IEEE 802.11n) additionally includes HT-SIG, HT-STF, and HT-LFT(s) fields in addition to the basic PPDU format. The HT PPDU format illustrated in Fig. 7(b) may be referred to as an HT-mixed format. Additionally, an HT-greenfield format PPDU may be defined, which corresponds to a format that does not include L-STF, L-LTF, and L-SIG, but consists of HT-GF-STF, HT-LTF1, HT-SIG, one or more HT-LTF, and Data fields (not illustrated).

[0106] An example of the VHT PPDU format (IEEE 802.11ac) includes VHT SIG-A, VHT-STF, VHT-LTF, and VHT-SIG-B fields in addition to the basic PPDU format (Fig. 7(c)).

[0107] An example of a HE PPDU format (IEEE 802.11ax) additionally includes RL-SIG (Repeated L-SIG), HE-SIG-A, HE-SIG-B, HE-STF, HE-LTF(s), and PE (Packet Extension) fields in addition to the basic PPDU format (Fig. 7(d)). Depending on specific examples of the HE PPDU format, some fields may be excluded or their lengths may vary. For example, the HE-SIG-B field is included in the HE PPDU format for multi-users (MUs), but the HE PPDU format for single users (SUs) does not include the HE-SIG-B. In addition, the HE trigger-based (TB) PPDU format does not include the HE-SIG-B, and the length of the HE-STF field may vary to 8us. The HE ER (Extended Range) SU PPDU format does not include the HE-SIG-B field, and the length of the HE-SIG-A field may vary to 16us. For example, RL-SIG can be configured identically to L-SIG. The receiving STA can determine that the received PPDU is a HE PPDU or an EHT PPDU, described later, based on the presence of RL-SIG.

[0108] The EHT PPDU format may include the EHT MU (multi-user) PPDU of FIG. 7(e) and the EHT TB (trigger-based) PPDU of FIG. 7(f). The EHT PPDU format is similar to the HE PPDU format in that it includes an RL-SIG following an L-SIG, but may include a U (universal)-SIG, an EHT-SIG, an EHT-STF, and an EHT-LTF following the RL-SIG.

[0109] The EHT MU PPDU in FIG. 7(e) corresponds to a PPDU that carries one or more data (or PSDUs) for one or more users. That is, the EHT MU PPDU can be used for both SU transmission and MU transmission. For example, the EHT MU PPDU can correspond to a PPDU for one receiving STA or multiple receiving STAs.

[0110] The EHT TB PPDU of Fig. 7(f) omits the EHT-SIG compared to the EHT MU PPDU. An STA that has received a trigger for UL MU transmission (e.g., a trigger frame or TRS (triggered response scheduling)) can perform UL transmission based on the EHT TB PPDU format.

[0111] The L-STF, L-LTF, L-SIG, RL-SIG, U-SIG (Universal SIGNAL), and EHT-SIG fields can be encoded and modulated so that even legacy STAs can attempt demodulation and decoding, and can be mapped based on a predetermined subcarrier frequency interval (e.g., 312.5 kHz). These can be referred to as pre-EHT modulated fields. Next, the EHT-STF, EHT-LTF, Data, and PE fields can be encoded and modulated so that they can be demodulated and decoded by an STA that has successfully decoded a non-legacy SIG (e.g., U-SIG and / or EHT-SIG) and obtained the information contained in the corresponding field, and can be mapped based on a predetermined subcarrier frequency interval (e.g., 78.125 kHz). These can be referred to as EHT modulated fields.

[0112] Similarly, in the HE PPDU format, the L-STF, L-LTF, L-SIG, RL-SIG, HE-SIG-A, and HE-SIG-B fields may be referred to as pre-HE modulation fields, and the HE-STF, HE-LTF, Data, and PE fields may be referred to as HE modulation fields. Additionally, in the VHT PPDU format, the L-STF, L-LTF, L-SIG, and VHT-SIG-A fields may be referred to as pre-VHT modulation fields, and the VHT STF, VHT-LTF, VHT-SIG-B, and Data fields may be referred to as VHT modulation fields.

[0113] The U-SIG included in the EHT PPDU format of FIG. 7 can be configured based on, for example, two symbols (e.g., two consecutive OFDM symbols). Each symbol (e.g., OFDM symbol) for the U-SIG can have a duration of 4 us, and the U-SIG can have a total duration of 8 us. Each symbol of the U-SIG can be used to transmit 26 bits of information. For example, each symbol of the U-SIG can be transmitted and received based on 52 data tones and 4 pilot tones.

[0114] U-SIGs can be configured in 20MHz units. For example, when an 80MHz PPDU is configured, the same U-SIG can be duplicated in 20MHz units. That is, four identical U-SIGs can be included in an 80MHz PPDU. When the bandwidth exceeds 80MHz, for example, for a 160MHz PPDU, the U-SIGs in the first 80MHz unit and the U-SIGs in the second 80MHz unit can be different.

[0115] For example, A uncoded bits may be transmitted via U-SIG, and a first symbol of U-SIG (e.g., a U-SIG-1 symbol) may transmit the first X bits of information out of a total A bits of information, and a second symbol of U-SIG (e.g., a U-SIG-2 symbol) may transmit the remaining Y bits of information out of a total A bits of information. The A bits of information (e.g., 52 uncoded bits) may include a CRC field (e.g., a field of 4 bits in length) and a tail field (e.g., a field of 6 bits in length). The tail field may be used to terminate the trellis of the convolutional decoder and may be set to 0, for example.

[0116] The A bit information transmitted by U-SIG can be divided into version-independent bits and version-dependent bits. For example, U-SIG can be included in a new PPDU format (e.g., UHR PPDU format) not shown in FIG. 7, and in the format of the U-SIG field included in the EHT PPDU format and the format of the U-SIG field included in the UHR PPDU format, the version-independent bits can be the same, and some or all of the version-dependent bits can be different.

[0117] For example, the size of the version-independent bits of U-SIG can be fixed or variable. The version-independent bits can be assigned only to U-SIG-1 symbols, or to both U-SIG-1 symbols and U-SIG-2 symbols. 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.

[0118] For example, the version-independent bits of the U-SIG may include a 3-bit PHY version identifier, which may indicate the PHY version (e.g., EHT, UHR, etc.) of the transmitted and received PPDUs. The version-independent bits of the 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. The version-independent bits of the U-SIG may include information about the length of a transmission opportunity (TXOP) and information about a BSS color ID.

[0119] For example, the version-dependent bits of the U-SIG may contain information that directly or indirectly indicates the type of PPDU (e.g., SU PPDU, MU PPDU, TB PPDU, etc.).

[0120] Information required for PPDU transmission and reception may be included in the U-SIG. For example, the U-SIG may further include information about bandwidth, information about the MCS technique applied to the non-legacy SIG (e.g., EHT-SIG or UHR-SIG), information indicating whether a dual carrier modulation (DCM) technique (e.g., a technique to achieve an effect similar to frequency diversity by reusing the same signal on two subcarriers) is applied to the non-legacy SIG, information about the number of symbols used for the non-legacy SIG, information about whether the non-legacy SIG is generated across the entire band, etc.

[0121] Some of the information required for transmitting and receiving a PPDU may be included in the U-SIG and / or the non-legacy SIG (e.g., EHT-SIG or UHR-SIG, etc.). For example, information about the type of the non-legacy LTF / STF (e.g., EHT-LTF / EHT-STF or UHR-LTF / UHR-STF, etc.), information about the length of the non-legacy LTF and the cyclic prefix (CP) length, information about the guard interval (GI) applicable to the non-legacy LTF, information about preamble puncturing applicable to the PPDU, information about resource unit (RU) allocation, etc. may be included only in the U-SIG, may be included only in the non-legacy SIG, or may be indicated by a combination of the information included in the U-SIG and the information included in the non-legacy SIG.

[0122] Preamble puncturing may refer to the transmission of a PPDU in which no signal is present in one or more frequency units within the PPDU's bandwidth. For example, the size of the frequency unit (or the resolution of the preamble puncturing) may be defined as 20 MHz, 40 MHz, etc. For example, preamble puncturing may be applied to a PPDU bandwidth greater than a certain size.

[0123] In the example of FIG. 7, non-legacy SIGs such as HE-SIG-B and EHT-SIG may include control information for the receiving STA. The non-legacy SIG may be transmitted over at least one symbol, and each symbol may have a length of 4 us. Information regarding the number of symbols used for the EHT-SIG may be included in a previous SIG (e.g., HE-SIG-A, U-SIG, etc.).

[0124] Non-legacy SIGs, such as HE-SIG-B and EHT-SIG, may contain common fields and user-specific fields. Common and user-specific fields may be coded separately.

[0125] In some cases, common fields may be omitted. For example, in a compressed mode where non-OFDMA (orthogonal frequency multiple access) is applied, common fields may be omitted, and multiple STAs may receive PPDUs (e.g., data fields of PPDUs) over the same frequency band. In a non-compressed mode where OFDMA is applied, multiple users may receive PPDUs (e.g., data fields of PPDUs) over different frequency bands.

[0126] The number of user-specific fields can be determined based on the number of users. A single user block field can contain up to two user fields. Each user field can be associated with either MU-MIMO allocation or non-MU-MIMO allocation.

[0127] The common field may include CRC bits and Tail bits, the length of the CRC bits may be determined as 4 bits, and the length of the Tail bits may be determined as 6 bits and set to 000000. The common field may include RU allocation information. The RU allocation information may include information about the location of RUs to which multiple users (i.e., multiple receiving STAs) are allocated.

[0128] An RU can contain multiple subcarriers (or tones). RUs can be used when transmitting signals to multiple STAs based on OFDMA techniques. RUs can also be defined when transmitting signals to a single STA. Resources can be allocated on an RU basis for non-legacy STFs, non-legacy LTFs, and data fields.

[0129] Depending on the PPDU bandwidth, an applicable RU size can be defined. The RU may be defined identically or differently for the applicable PPDU format (e.g., HE PPDU, EHT PPDU, UHR PPDU, etc.). For example, in the case of an 80MHz PPDU, the RU arrangements of HE PPDU and EHT PPDU may be different. The applicable RU size, RU number, RU position, DC (direct current) subcarrier position and number, null subcarrier position and number, guard subcarrier position and number, etc. for each PPDU bandwidth can be referred to as a tone plan. For example, a tone plan for a wide bandwidth can be defined in the form of multiple repetitions of a low bandwidth tone plan.

[0130] RUs of different sizes can be defined, such as 26-ton RU, 52-ton RU, 106-ton RU, 242-ton RU, 484-ton RU, 996-ton RU, 2X996-ton RU, 4X996-ton RU, etc. A multiple RU (MRU) is distinguished from multiple individual RUs and corresponds to a group of subcarriers consisting of multiple RUs. For example, one MRU can be defined as 52+26-tons, 106+26-tons, 484+242-tons, 996+484-tons, 996+484+242-tons, 2X996+484-tons, 3X996-tons, or 3X996+484-tons. Additionally, multiple RUs constituting one MRU may or may not be consecutive in the frequency domain.

[0131] The specific size of an RU may be reduced or expanded. Therefore, the specific size of each RU (i.e., the number of corresponding tones) in the present disclosure is not limited and is exemplary. Furthermore, within a given bandwidth (e.g., 20, 40, 80, 160, 320 MHz, etc.) in the present disclosure, the number of RUs may vary depending on the RU size.

[0132] The names of each field in the PPDU formats of FIG. 7 are exemplary and the scope of the present disclosure is not limited by those names. Furthermore, the examples of the present disclosure can be applied not only to the PPDU format exemplified in FIG. 7, but also to a new PPDU format in which some fields are excluded and / or some fields are added based on the PPDU formats of FIG. 7.

[0133] Multi-Access Point (MAP) operation

[0134] Below, examples of the present disclosure for multi-access point (MAP) operation are described.

[0135] MAP operation can be defined as an operation between a master AP (or sharing AP) and a slave AP (or shared AP).

[0136] The master AP initiates and controls MAP operations for transmission and reception between multiple APs. It groups slave APs and manages links with them to enable information sharing. The master AP manages information about the BSS comprised of the slave APs and the STAs associated with that BSS.

[0137] Slave APs can associate with a master AP and share control information, management information, and data traffic. Slave APs perform the same basic functions as APs, establishing a base station service (BSS) in a wireless LAN.

[0138] In MAP operation, an STA can associate with a slave AP or a master AP and form a BSS.

[0139] In a MAP environment, the master AP and slave APs can directly transmit and receive with each other. The master AP and STA may not be able to directly transmit and receive with each other. A slave AP (e.g., a slave AP associated with an STA) can directly transmit and receive with the STA. One of the slave APs can become the master AP.

[0140] MAP operation is a technique in which one or more APs transmit and receive information to one or more STAs. For example, coordinated-time division multiple access (C-TDMA), which divides allocations between APs along the time axis, coordinated-orthogonal frequency division multiple access (C-OFDMA), which divides allocations along the frequency axis, and coordinated-spatial reuse (C-SR) techniques that utilize spatial reuse can be applied for MAP operation. Alternatively, coordinated beamforming (C-BF) or joint beamforming techniques, which cooperatively perform simultaneous transmission and reception, can also be applied to MAP operation.

[0141] FIG. 8 is a diagram for explaining various transmission and reception techniques in a MAP environment to which the present disclosure can be applied.

[0142] As in the conventional method, when a BSS AP transmits to a BSS STA, this can be referred to as STX (single transmission). STX suffers from the problem of reduced transmission and reception performance for users / STAs located at the cell edge due to interference with neighboring APs. For example, as shown in Figure 8(a), if AP1 and AP2 transmit to STA1 and STA2, respectively, at the same time and within the same frequency bandwidth, a collision may occur on the wireless medium.

[0143] In the MAP technique, performance can be improved by reducing inter-symbol interference (ISI) through cooperation between neighboring APs, or by performing joint transmissions. For example, in the C-OFDMA method of Fig. 8(b), interference can be avoided by simultaneously transmitting to STA1 in the first bandwidth and transmitting to STA2 in the second bandwidth. The example of Fig. 8(c) shows a cooperative beamforming or nulling technique in which AP1 nulls the interference to AP2 and / or STA2 while transmitting to STA1, and AP2 nulls the interference to AP1 and / or STA1 while transmitting to STA2. Fig. 8(d) shows an AP selection method in which an AP with a good channel condition among neighboring APs performs transmission. Joint transmission (JTX) or joint reception (JRX) may be applied, in which multiple APs cooperate to transmit or receive simultaneously, as in the example of Fig. 8(e), and further, joint MU-MIMO may be supported.

[0144] In the examples of this disclosure, multi-AP operation is assumed to be performed as follows.

[0145] Step 1: Allocate resource areas to each AP through a trigger frame from the master AP (i.e., AP-to-AP trigger frame, or master trigger frame).

[0146] Step 2: Each AP performs DL (i.e., from AP to STA) data transmission in the resource area allocated to it, or transmits a trigger frame (i.e., AP-to-STA trigger frame) for UL (i.e., from STA to AP) data transmission in the resource area allocated to it.

[0147] Step 3: STA sends a response to DL data or sends UL data (e.g., TB PPDU)

[0148] If the resources distributed between APs are frequency resources, it may correspond to the C-OFDMA method, if it is time resources, it may correspond to the C-TDMA technique, and if it is space resources (or beams), it may correspond to the CBF method. In the examples described below, it is assumed that the C-OFDMA technique, i.e., multi-AP operation is performed using resources distinguished in the frequency domain, is representative. However, the scope of the present disclosure is not limited thereto, and may additionally or alternatively include multi-AP operation using resources distinguished in other domains (e.g., time domain and / or space domain).

[0149] Multi-link operation

[0150] Below, the multi-link operation supported by the STA according to the present disclosure is described.

[0151] The STA (AP STA and / or non-AP STA) described in the present disclosure can support multi-link (ML) communication. ML communication may refer to communication that supports multiple links. Links related to ML communication may include channels (e.g., 20 / 40 / 80 / 160 / 240 / 320MHz channels) of a frequency band (e.g., 2.4GHz band, 5GHz band, 6GHz band, etc.) in which the STA operates. The multiple links used for ML communication may be configured in various ways. For example, the multiple links supported for one STA for ML communication may belong to the same frequency band or may belong to different frequency bands. In addition, each link may correspond to a frequency unit of a predetermined size (e.g., a channel, a subchannel, an RU, etc.). In addition, some or all of the multiple links may be frequency units of the same size or may be frequency units of different sizes.

[0152] When one STA supports multiple links, the transmitting and receiving devices supporting each link can operate as one logical STA. That is, an MLD is a device that has one or more affiliated STAs as a logical entity and a single MAC service access point (SAP) for one MAC data service and logical link control (LLC). A non-AP MLD refers to an MLD in which each STA affiliated with the MLD is a non-AP STA. A multi-radio non-AP MLD refers to a non-AP MLD that supports receiving or exchanging frames on more than one link at a time. An AP MLD refers to an MLD in which each STA affiliated with the MLD is an AP STA.

[0153] Multi-link operation (MLO) can enable a non-AP MLD to discover, authenticate, associate, and set up multiple links with an AP MLD. Based on the supported capabilities exchanged during the association procedure, each link can enable channel access and frame exchange between the non-AP MLD and the AP MLD. An STA affiliated with an MLD can select and manage its capabilities and operating parameters independently from other STA(s) affiliated with the same MLD.

[0154] Through the multi-link setup process, the AP MLD and / or the non-AP MLD can transmit and receive link-related information that the MLD can support. The link-related information may include one or more of information about whether the MLD supports simultaneous transmit and receive (STR) operation or non-simultaneous transmit and receive (NSTR) operation on multiple links, information about the number / upper limit of UL / DL links, information about the location / bandwidth / resource of UL / DL links, information about frame types (e.g., management, control, data, etc.) that are available or preferred on at least one UL / DL link, information about an ACK policy that is available or preferred on at least one UL / DL link, or information about a traffic identifier (TID) that is available on at least one UL / DL link.

[0155] An AP MLD (e.g., NSTR mobile AP MLD) can set one of the multiple links as the primary link. The AP MLD may transmit beacon frames, probe response frames, and group-addressed data frames only on the primary link. The remaining link(s) of the multiple links may be referred to as non-primary links. An AP MLD operating on a non-primary link may operate so as not to transmit beacon frames or probe response frames. In addition, a non-AP MLD may perform frame exchanges during authentication, (re)association, and 4-way handshaking only on the primary link.

[0156] A setup link is defined as enabled if at least one traffic identifier (TID) is mapped to the link through the multi-link setup process, and a setup link can be defined as disabled if no TID is mapped to the link. A TID must always be mapped to at least one setup link unless admission control is used. By default, a TID is mapped to all setup links, so all setup links can be enabled.

[0157] When a link is activated, it can be used for frame exchange, depending on the power state of the non-AP STAs operating on that link. Only MSDUs or A-MSDUs with TIDs mapped to the activated link can be transmitted on that link. Management frames and control frames can only be transmitted on the activated link.

[0158] When a link is disabled, that link may not be used for frame exchange, including management frames for both DL and UL.

[0159] During a multi-link setup, activation / deactivation of individual links can be directed through TID-to-Link mapping. TID-to-Link mapping can be performed in default mapping mode or / and negotiation mapping mode.

[0160] Dynamic TXOP sharing

[0161] Broad frequency allocation and the resulting advancements in transmission technology are leading to a proliferation of services and applications requiring low-latency (LL) communications. For example, low-latency communications may be required to support augmented reality (AR) experiences using eXtended Reality (XR) devices. Furthermore, the interactive nature of low-latency communications necessitates bidirectional, rather than one-way, data transmission and reception.

[0162] TXOP is defined as a method to guarantee data transmission by a TXOP holder for a certain period of time. Existing TXOP can be used for basically one-way data transmission (e.g., data transmission from a TXOP holder to a TXOP responder). If a TXOP holder can share the channel with a device performing low-latency communication during the TXOP (or during the TXOP duration) (e.g., TXOP sharing), especially dynamically, it can more effectively support bidirectional low-latency services / applications.

[0163] Existing TXOP sharing schemes (e.g., triggered TXOP sharing procedures) can support data transmission from a TXOP responder to a TXOP holder during a single time interval allocated within a TXOP duration, but there is no provision for a TXOP responder to dynamically request TXOP sharing or a TXOP holder to dynamically recover a shared TXOP. Therefore, a specific scheme for dynamically sharing TXOPs is required to improve the existing TXOP sharing operation to support cases where the traffic that the TXOP responder wants to transmit has low-latency characteristics and / or to support bidirectional low-latency traffic transmission and reception.

[0164] Various examples of the present disclosure for efficient dynamic TXOP sharing schemes are described below.

[0165] Figure 9 shows examples of topologies of low-latency communication to which the present disclosure can be applied.

[0166] In the example of Fig. 9, as an example of low-latency communication, it is assumed that rendering data is provided to an HMD (head mounted display) from a main device (e.g., a personal computer (PC) or a server) that transmits rendering data, and pose data of a user is provided to the main device from the HMD, and the data exchanged between the devices may have low-latency characteristics. However, the scope of the present disclosure is not limited to these examples of devices and / or data, and may be applied to various devices and / or data for supporting various bidirectional low-latency communications.

[0167] Figure 9(a) illustrates an exemplary topology in which rendering data is provided from a PC, the main device, to an HMD, and pose data is provided from the HMD to the main device. The PC and HMD may each correspond to non-AP STAs and can perform direct communication.

[0168] Figure 9(b) illustrates an exemplary topology in which rendering data is transmitted from an edge server, which is a main device, to an HMD via an AP, and pose data is provided from the HMD to the main device via the AP. The HMD may be a non-AP STA and may communicate directly with the AP. Communication between the main device and the HMD may be performed via (via) the AP.

[0169] Figure 9(c) illustrates an exemplary topology in which rendering data from a PC, the main device, is transmitted to the HMD via an AP, and pose data is provided from the HMD to the main device via the AP. The PC and the HMD may each correspond to non-AP STAs, and communication between them may be performed via (via) the AP. The PC and the AP may communicate directly, and the HMD and the AP may communicate directly.

[0170] In the examples described below, the TXOP holder can correspond to the PC of Fig. 9(a), the AP of Fig. 9(b), and the PC of Fig. 9(c), and the TXOP responder can correspond to the HMD of Fig. 9(a), the HMD of Fig. 9(b), and the HMD of Fig. 9(c). In this case, in the case of Fig. 9(c), communication between the TXOP holder and the TXOP responder can be performed via (or through) the AP, and in the examples described below, communication between the TXOP holder and the TXOP responder can be applied to direct communication that does not go through the AP, and can also be applied to communication that goes through the AP.

[0171] In this disclosure, for convenience of explanation, the topology of Fig. 9(c) is assumed and explained, but the scope of this disclosure can be applied to other topologies illustrated in Fig. 9 and can also be applied to various other wireless LAN-based topologies.

[0172] Various examples of dynamic TXOP sharing of the present disclosure may also be applied to multi-link (ML) and / or multi-AP (MAP) operations. For example, for ML, link information to which dynamic TXOP sharing according to the present disclosure is applied may be transmitted and received between a TXOP holder and a TXOP responder. Additionally or alternatively, for example, for MAP, in addition to dynamic TXOP sharing between APs, TXOP sharing within each AP (e.g., between an AP and a STA associated with the AP), i.e., hierarchical TXOP sharing, may be applied.

[0173] Although the present disclosure assumes a single link and single AP environment for convenience of explanation, the scope of the present disclosure can be extended and applied to ML operations and / or MAP operations.

[0174] FIG. 10 is a diagram illustrating an example of the operation of the first STA according to the present disclosure.

[0175] In step S1010, the first STA may transmit, to the second STA, a first frame including information indicating the presence of traffic to be transmitted from the first STA within the TXOP duration of the second STA.

[0176] For example, the first frame may correspond to a response to a frame from the second STA within the TXOP duration. For example, the frame from the second STA may be a frame containing data (e.g., rendering data) transmitted from the second STA to the first STA within the TXOP. The response thereto may correspond to a block ACK (BA) frame. In this case, information indicating the presence of traffic to be transmitted from the first STA (e.g., low-latency traffic such as pause data) may be included in the block ACK frame.

[0177] Additionally or alternatively, the first frame may further include information about the number of transmissions (or sharing numbers) related to the traffic to be transmitted by the first STA (e.g., required for low-latency traffic transmission).

[0178] Before transmitting the first frame in step S1010, TXOP sharing indication information may be received from the second STA at the first STA. A response to the TXOP sharing indication information may be transmitted from the first STA to the second STA. For example, the TXOP sharing indication information may be included in a MU-RTS TXS (multi-user request to send TXOP sharing) frame or a control frame. For example, a response to the TXOP sharing indication information may correspond to a CTS (clear to send) frame or an ACK frame. For example, a frame including the TXOP sharing indication information may include information on one or more of the number of transmissions allowed for TXOP sharing (or the number of allowed shares), the maximum number of transmissions (or the maximum number of shares), the minimum number of transmissions (or the minimum number of shares), the transmission time length (or the sharing time length), or the time length per transmission number (or the time length per share number).

[0179] In step S1020, after transmitting the first frame, the first STA can transmit a second frame including traffic to the second STA.

[0180] For example, the second frame may be transmitted a predetermined time after the transmission of the first frame (i.e., without transmission or reception of other frames between the first and second frames). Alternatively, the second frame may be transmitted based on a trigger frame received from the second STA after the transmission of the first frame.

[0181] After the second frame is transmitted in step S1020, a third frame including TXOP shared recovery indication information may be transmitted from the second STA to the first STA. After a predetermined time after receiving the third frame, data (e.g., rendering data) may be transmitted from the second STA to the first STA. For example, the third frame may correspond to a response frame (e.g., a block ACK frame) to the second frame, or may correspond to a frame (e.g., a control frame) transmitted additionally to a response frame to the second frame.

[0182] In the example of FIG. 10, the first STA may correspond to a TXOP responder. The second STA may correspond to a TXOP holder. The first STA may be a non-AP STA or an AP STA. The second STA may be an AP STA or a non-AP STA.

[0183] The example of FIG. 10 may also be applied to various topologies illustrated in FIG. 9. For example, frame exchange between the first STA and the second STA may be performed directly between the first STA, which is a non-access point (non-AP) STA, and the second STA, which is a non-AP STA (FIG. 9(a)), directly between the first STA, which is a non-AP STA, and the second STA, which is an AP STA (FIG. 9(b)), or may be performed via an AP between the first STA, which is a non-AP STA, and the second STA, which is a non-AP STA (FIG. 9(c)).

[0184] The method described in the example of FIG. 10 may be performed by the first device (100) of FIG. 1. For example, one or more processors (102) of the first device (100) of FIG. 1 may be configured to transmit, to the second STA, a first frame including information indicating the presence of traffic to be transmitted from the first STA, via one or more transceivers, within the TXOP duration of the second STA; and, after transmitting the first frame, transmit, to the second STA, a second frame including the traffic, via one or more transceivers. Furthermore, one or more memories (104) of the first device (100) may store commands for performing the method described in the example of FIG. 10 or the examples described below when executed by one or more processors (102).

[0185] FIG. 11 is a diagram illustrating an example of the operation of a second STA according to the present disclosure.

[0186] In step S1110, the second STA may receive, from the first STA, a first frame including information indicating the presence of traffic to be transmitted from the first STA within the TXOP duration of the second STA.

[0187] In step S1120, the second STA can receive a second frame including traffic from the first STA after receiving the first frame.

[0188] In the example of Fig. 11, the specific description of the first frame, the second frame, and the frames transmitted and received before or after them is the same as the example of Fig. 10, so redundant description is omitted.

[0189] The method described in the example of FIG. 11 may be performed by the second device (200) of FIG. 1. For example, one or more processors (202) of the second device (200) of FIG. 1 may be configured to receive, from the first STA via one or more transceivers, a first frame including information indicating the presence of traffic to be transmitted from the first STA within the TXOP duration of the second STA; and, after receiving the first frame, receive, from the first STA via one or more transceivers, a second frame including the traffic. Furthermore, one or more memories (204) of the second device (200) may store commands for performing the method described in the example of FIG. 11 or the examples described below when executed by one or more processors (202).

[0190] The examples of FIGS. 10 and 11 may correspond to some of the various examples of the present disclosure. Below, various examples of the present disclosure, including the examples of FIGS. 10 and 11, will be described in more detail.

[0191] Although the embodiments described below assume the topology of FIG. 9(c), single-link, and single-AP, the embodiments described below can be equally applied to other various topologies, multi-links, and / or multi-APs.

[0192] In the embodiments described below, dynamic TXOP sharing may also be simply referred to as TXOP sharing. That is, since the TXOP sharing procedure including the TXOP sharing instruction, TXOP sharing request, and / or TXOP sharing recovery defined in the embodiments for TXOP sharing according to the present disclosure is not defined in the existing TXOP sharing procedure, a new TXOP sharing procedure including these features can be distinguished from the existing TXOP sharing procedure even if it is not explicitly called a dynamic TXOP sharing procedure.

[0193] Example 1

[0194] This embodiment is for TXOP sharing indication.

[0195] A TXOP holder (AP or non-AP STA) may transmit an indication for TXOP sharing to a TXOP responder by transmitting a control frame at the beginning of a TXOP or within the TXOP duration. The indication for TXOP sharing (i.e., TXOP sharing indication information) may correspond to information informing the TXOP responder that the TXOP holder is willing (or permitted to share) and / or has such capability to share the opportunity for data transmission during the entire TXOP duration or during a specific time within the TXOP duration.

[0196] A control frame containing TXOP sharing instruction information may be defined using an existing frame or as a new frame. When using an existing frame, a new sharing mode corresponding to the TXOP sharing instruction may be defined.

[0197] For example, the MU-RTS TXS frame can be used to indicate TXOP sharing. In this case, a new sharing mode distinct from the existing TXS mode can be defined to indicate that data transmission opportunities are shared during the entire TXOP or for a specific time within the TXOP.

[0198] For example, an exchange of RTS and CTS frames may be used to indicate a TXOP sharing. In this case, reserved bit(s) in the RTS and / or CTS frames may be used to indicate that data transmission opportunities are to be shared during the entire TXOP or for a specific period of time within the TXOP.

[0199] For example, a control frame defined as a new frame may be used to indicate TXOP sharing. In this case, the new frame may include information about the initiation of a TXOP and TXOP sharing.

[0200] Control frames conveying TXOP sharing indication information may include additional information. For example, the additional information may include information about one or more of the number of transmissions allowed for TXOP sharing (or the number of allowed shares), the maximum number of transmissions (or the maximum number of shares), the minimum number of transmissions (or the minimum number of shares), the transmission time length (or the share time length), or the time length per transmission (or the time length per share).

[0201] For example, the number of TXOP shares can be counted as the number of times the TXOP holder releases / recovers the data transmission of the TXOP responder. For example, during one share, the TXOP responder may perform only one transmission (e.g., transmission of one frame or one PPDU) or may perform multiple transmissions (e.g., transmission of multiple frames or multiple PPDUs).

[0202] The number of TXOP shares can be specified as a minimum and / or maximum number. For example, the TXOP holder may indicate that it can provide the TXOP responder with at least 30 opportunities to transmit data within a 3-ms TXOP period. This allows the TXOP responder to transmit as many times as it needs, within the allowable range.

[0203] The length of the shareable time interval during a TXOP may be indicated together with or instead of information about the number of TXOP shares. For example, when indicated together with information about the number of TXOP shares, information about the total time interval corresponding to the total number of shares and / or the time interval corresponding to a single share may be indicated.

[0204] A frame containing the above TXOP sharing instruction information and / or additional information may be addressed to a specific device (e.g., a specific TXOP responder).

[0205] FIG. 12 is a diagram showing examples of TXOP sharing instructions according to the present disclosure.

[0206] In the example of Figure 12, frame exchange between the TXOP holder and the TXOP responder may be performed directly or through another entity (e.g., through the relay function of the AP).

[0207] In the example of Fig. 12(a), TXOP sharing instruction information can be provided from the TXOP holder to the TXOP responder via an MU-RTS TXS frame. In response, the TXOP responder can transmit a CTS frame to the TXOP holder. Within the TXOP duration, the TXOP holder can transmit data (e.g., rendering data from the PC / server of Fig. 9 to the HMD) to the TXOP responder, and in response, the TXOP responder can transmit a block ACK (BA) frame to the TXOP holder.

[0208] In the example of Fig. 12(b), TXOP sharing instruction information can be provided from the TXOP holder to the TXOP responder via a control frame (e.g., a newly defined control frame related to the TXOP sharing procedure). In response, the TXOP responder can transmit an ACK frame to the TXOP holder. For example, the ACK frame may correspond to an existing frame (e.g., a CTS frame) or another frame containing ACK information. Subsequent data transmission and reception and BA frame transmission and reception are identical to the example of Fig. 12(a).

[0209] In the examples of Fig. 12, the data transmitted from the TXOP holder corresponds to data transmitted within a general TXOP (e.g., rendering data), and the operation of the TXOP responder transmitting traffic (e.g., LL traffic such as pause data) through the TXOP sharing procedure is described in the examples described below. The example of Fig. 12 mainly shows the operation of the TXOP holder providing TXOP sharing instruction information to the TXOP responder as prior information for TXOP sharing.

[0210] Example 2

[0211] This embodiment is for TXOP sharing operation.

[0212] To share a TXOP, a TXOP responder may transmit information to the TXOP holder indicating that it has traffic it wishes to transmit (e.g., LL traffic). This may correspond to a TXOP sharing request. This TXOP sharing request may be based on TXOP sharing indication information (and additional information) previously provided to the TXOP responder by the TXOP holder.

[0213] Information indicating the presence of traffic to be transmitted from a TXOP responder may be transmitted to a TXOP holder as a response to a data transmission from the TXOP holder.

[0214] For example, a BA frame or a Multi-BA frame may be used in response to a data transmission from a TXOP holder. For example, the Multi-BA frame may be a Multi-STA BA frame, a Multi-TID BA frame, a Multi-Link BA frame, or a BA frame of another or new variant. The format of the BA information field of the BA frame may be determined according to the variant. In this case, the TXOP responder may use the BA control field of the BA frame or the Multi-BA frame or the reserved bit(s) of the Multi-BA control field to inform the TXOP holder of the presence or absence of LL traffic to be transmitted. Although the description of the embodiment is provided using a BA frame, the examples of the present disclosure may also be applied to a Multi-BA frame.

[0215] FIG. 13 is a diagram showing an exemplary format of a BA frame to which the present disclosure can be applied.

[0216] The MAC header of a BA frame may include a Frame Control field (2 octets), a Duration / ID field (2 octets), a Receiver Address (RA) field (6 octets), and a Transmitter Address (TA) field (6 octets). The frame body of a BA frame may include a BA Control field (2 octets), a BA Information field (variable length), and additionally, a Frame Check Sequence (FCS) field (4 octets).

[0217] Bit positions B3-B11 of the BA control field are defined as reserved bits. In addition, the combination of values ​​of the multi-TID (traffic ID) subfield at position B1 and the compressed bitmap subfield at position B2 are defined as shown in Table 1 below, and among the combinations of bit values ​​of 00, 01, 10, and 11, the combination of 10 is defined as a reserved value.

[0218] Multi-TID Subfield Value Compressed Bitmap Subfield Value Block ACK Frame Variant 00 Basic Block ACK 01 Compressed Block ACK 10 Reserved 11 Multi-TID Block ACK

[0219] For example, information about the presence of LL traffic to be transmitted from a TXOP responder may be indicated through a reserved value (10) among the reserved bits (B3-B11) of the BA control field in the BA frame and / or a combination of values ​​of the multi-TID subfield and the compressed bitmap subfield.

[0220] In addition to the information indicating the presence of traffic to be transmitted from the TXOP responder, information regarding the number of transmissions related to the traffic to be transmitted may also be indicated from the TXOP responder to the TXOP holder. The information regarding the number of transmissions may indicate how many data frames (or PPDUs) are required for the TXOP responder to transmit all of the LL traffic it intends to transmit.

[0221] FIG. 14 is a diagram showing examples of transmission operations through TXOP sharing according to the present disclosure.

[0222] In the example of Figure 14, frame exchange between the TXOP holder and the TXOP responder may be performed directly or through another entity (e.g., an AP).

[0223] In the example of Fig. 14(a), after the TXOP responder notifies the TXOP holder of the presence of LL traffic, after a predetermined period of time, the TXOP responder can transmit a data frame containing LL traffic to the TXOP holder.

[0224] For example, the given time may be SIFS. SIFS is merely an example, and predefined IFSs of other lengths may be applied as the given time interval.

[0225] For example, parameters required for transmission of a data frame containing LL traffic of a TXOP responder can be determined based on information obtained through data reception from the TXOP holder.

[0226] For example, if a TXOP responder indicates to the TXOP holder, through a BA frame, information about the number of transmissions of LL traffic in addition to the indication of the presence of LL traffic, the TXOP responder may transmit data frames containing LL traffic a number of times less than the number of transmissions notified to the TXOP holder.

[0227] In the example of Fig. 14(b), after the TXOP responder notifies the TXOP holder of the presence or absence of LL traffic, the TXOP responder may receive a control frame (e.g., a trigger frame) from the TXOP holder, and transmit a data frame including LL traffic to the TXOP holder based on the control frame (or trigger frame).

[0228] For example, after receiving a control frame (or trigger frame) from a TXOP holder, a TXOP responder may transmit a data frame containing LL traffic to the TXOP holder after a predetermined period of time (e.g., SIFS).

[0229] For example, through the aforementioned control frame (or trigger frame), response information indicating the presence or absence of LL traffic of the TXOP responder can be transmitted from the TXOP holder to the TXOP responder.

[0230] For example, a TXOP responder may request a TXOP share for transmitting LL traffic (i.e., to announce the presence of LL traffic to be transmitted), but the TXOP holder may reject the request. In this case, information indicating the rejection may be transmitted as response information from the TXOP holder to the TXOP responder via a control frame.

[0231] Alternatively, the TXOP holder may accept the TXOP share request of the TXOP responder. That is, the TXOP holder may allow the transmission of LL traffic in response to the presence indication information of LL traffic to be transmitted from the TXOP responder. In this case, the TXOP holder may provide the TXOP responder with information such as resource information (e.g., resource unit (RU) allocation information), modulation and coding scheme (MCS), Number of Spatial Streams (Nss), transmission power, etc., as response information, through a control frame (or trigger frame).

[0232] Based on these control frames (or trigger frames), the TXOP responder can transmit a data frame containing LL traffic to the TXOP holder via a PPDU in TB-PPDU format or SU-PPDU format.

[0233] Example 3

[0234] This embodiment is about TXOP shared recovery.

[0235] After a TXOP holder shares a TXOP with a TXOP responder (i.e., after allowing / receiving data transmission from the TXOP responder within the TXOP duration), the TXOP holder can regain the right to transmit again.

[0236] FIG. 15 is a diagram showing examples of TXOP shared recovery according to the present disclosure.

[0237] In the example of Figure 15, frame exchange between the TXOP holder and the TXOP responder may be performed directly or through another entity (e.g., an AP).

[0238] In the example of Figure 15(a), the TXOP holder can notify the TXOP responder of the recovery of transmission rights (i.e., recovery of TXOP sharing) by using a BA frame transmitted as a response to a data frame containing LL traffic received from the TXOP responder.

[0239] For example, the point in time when the transmission right is restored may be a predetermined time (e.g., SIFS) after transmission of a BA frame containing an indication to restore the transmission right (i.e., TXOP sharing restoration indication). For example, the TXOP holder may notify the TXOP responder of the restoration of the transmission right (i.e., TXOP sharing restoration) through reserved bit(s) of the BA control field of the BA frame. That is, after a predetermined time after transmission of the BA frame, the TXOP holder may perform / resume data transmission to the TXOP responder. Alternatively, transmission of the TXOP sharing restoration indication may be initiated by the TXOP holder when the data frame sent by the TXOP responder is the last frame.

[0240] In the example of Figure 15(b), the TXOP holder may transmit a BA frame in response to a data frame containing LL traffic received from the TXOP responder, and then notify the TXOP responder of the restoration of transmission rights (i.e., restoration of TXOP sharing) via a control frame. For example, such a control frame may be a CTS-to-Self frame.

[0241] For example, the point in time when the transmission right is restored may be a predetermined time (e.g., SIFS) after the transmission of a control frame containing an instruction to restore the transmission right (i.e., a TXOP sharing restoration instruction). That is, after the predetermined time after the transmission of the control frame, the TXOP holder can perform / resume data transmission to the TXOP responder.

[0242] Although not shown in Figure 15(b), a TXOP responder that receives a control frame including a TXOP shared recovery instruction may also transmit an ACK frame responding to the control frame to the TXOP holder.

[0243] In this case, the point in time when the transmission right is restored may be a predetermined time (e.g., SIFS) after the TXOP holder receives an ACK frame from the TXOP responder responding to the control frame containing the transmission right restoration instruction (i.e., TXOP sharing restoration instruction). That is, after a predetermined time after receiving an ACK frame for the control frame, the TXOP holder can perform / resume data transmission to the TXOP responder.

[0244] In the examples of FIG. 15, TXOP sharing recovery using a BA frame or a control frame can occur even before the TXOP responder, which has been granted transmission rights from the TXOP holder, has completed transmitting data frames from the TXOP responder as many times as the number of LL traffic instructed to the TXOP holder. That is, the TXOP holder can instruct the TXOP responder to recover TXOP sharing even before the TXOP responder has transmitted all of its LL traffic.

[0245] The TXOP sharing operation according to the examples of the present disclosure can overcome the limitations of the existing TXOP sharing procedure and support a flexible and efficient TXOP sharing procedure in which a TXOP holder instructs dynamic TXOP sharing, a TXOP responder dynamically requests TXOP sharing, and the TXOP holder dynamically recovers TXOP sharing. Accordingly, services / applications requiring low-latency communication by multiple devices can be effectively supported. In addition, the examples of the present disclosure can be applied to various low-latency communication topologies and can be extended to ML operations and / or MAP operations.

[0246] The embodiments described above are combinations of components and features of the present disclosure in a predetermined form. Each component or feature should be considered optional unless explicitly stated otherwise. Each component or feature may be implemented without being combined with other components or features. Furthermore, it is also possible to form embodiments of the present disclosure by combining some components and / or features. The order of operations described in the embodiments of the present disclosure may be changed. Some components or features of one embodiment may be included in another embodiment or may be replaced with corresponding components or features of another embodiment. It is self-evident that claims that do not have an explicit citation relationship in the patent claims may be combined to form embodiments or incorporated as new claims through post-application amendments.

[0247] It will be apparent to those skilled in the art that the present disclosure may be embodied in other specific forms without departing from the essential characteristics of the present disclosure. Therefore, the above detailed description should not be construed as limiting in any respect, but rather as illustrative. The scope of the present disclosure should be determined by a reasonable interpretation of the appended claims, and all modifications within the scope of equivalents of the present disclosure are intended to be included within the scope of the present disclosure.

[0248] The scope of the present disclosure includes software or machine-executable instructions (e.g., an operating system, an application, firmware, a program, etc.) that cause operations according to the methods of various embodiments to be executed on a device or a computer, and a non-transitory computer-readable medium having such software or instructions stored thereon and executable on the device or computer. Instructions that can be used to program a processing system to perform the features described in the present disclosure can be stored on / in a storage medium or a computer-readable storage medium, and a computer program product including such a storage medium can be used to implement the features described in the present disclosure. The storage medium can include, but is not limited to, high-speed random access memory, such as DRAM, SRAM, DDR RAM, or other random access solid state memory devices, and can include non-volatile memory, such as one or more magnetic disk storage devices, optical disk storage devices, flash memory devices, or other non-volatile solid state storage devices. The memory optionally includes one or more storage devices remotely located from the processor(s). The memory or, alternatively, the non-volatile memory device(s) within the memory comprise a non-transitory computer-readable storage medium. The features described in this disclosure may be incorporated into software and / or firmware stored on any of the machine-readable media, which may control the hardware of the processing system and allow the processing system to interact with other mechanisms that utilize results according to embodiments of the present disclosure. Such software or firmware may include, but is not limited to, application code, device drivers, operating systems, and execution environments / containers.

[0249] The method proposed in this disclosure has been described with a focus on examples applied to IEEE 802.11-based systems, but can be applied to various wireless LANs or wireless communication systems in addition to IEEE 802.11-based systems.

Claims

1. A step of transmitting, by a first station (STA), to a second STA, a first frame including information indicating the presence of traffic to be transmitted from the first STA within a transmission opportunity (TXOP) duration of the second STA; and A method comprising the step of transmitting, by the first STA, a second frame including the traffic to the second STA after transmitting the first frame.

2. In paragraph 1, A method wherein the first frame corresponds to a response to a frame from the second STA within the TXOP duration.

3. In paragraph 2, A method wherein a frame from the second STA includes data from the second STA to the first STA.

4. In paragraph 2, The response to the frame from the second STA corresponds to a block ACK (acknowledgement) frame, A method wherein information indicating the presence of traffic to be transmitted from the first STA is included in the block ACK frame.

5. In paragraph 1, The second frame is transmitted a predetermined time after the first frame is transmitted, or A method wherein the second frame is transmitted based on a trigger frame received from the second STA after transmission of the first frame.

6. In paragraph 1, A method, wherein the first frame further includes information about the number of transmissions related to the traffic to be transmitted by the first STA.

7. In paragraph 1, Before transmitting the first frame above: TXOP sharing instruction information is received from the second STA; and A method in which a response to the above TXOP sharing instruction information is transmitted to the second STA.

8. In paragraph 7, The above TXOP sharing instruction information is included in the MU-RTS TXS (multi-user request to send TXOP sharing) frame or control frame, A method in which a response to the above TXOP sharing instruction information corresponds to a CTS (clear to send) frame or an ACK frame.

9. In paragraph 7, A method wherein a frame including the above TXOP sharing instruction information further includes information about one or more of the allowed number of transmissions, the maximum number of transmissions, the minimum number of transmissions, the length of time shared, or the length of time per number of transmissions.

10. In paragraph 1, After transmitting the second frame above: A third frame including TXOP shared recovery indication information is transmitted from the second STA to the first STA; and A method in which data is transmitted from the second STA to the first STA a predetermined time after receiving the third frame.

11. In Article 10, A method wherein the third frame corresponds to a response frame to the second frame or a frame transmitted additionally to the response frame.

12. In paragraph 11, The above response frame corresponds to a block ACK frame, The method wherein the additionally transmitted frame corresponds to a control frame.

13. In paragraph 1, Frame exchange between the first STA and the second STA is: or performed directly between the first STA, which is a non-access point (non-AP) STA, and the second STA, which is a non-AP STA; or is performed directly between the first STA, which is a non-AP STA, and the second STA, which is an AP STA; or A method performed between the first STA, which is a non-AP STA, and the second STA, which is a non-AP STA, through an AP.

14. In paragraph 1, A method wherein the first STA is a TXOP responder and the second STA is a TXOP holder.

15. One or more transmitters / receivers; and comprising one or more processors coupled to said one or more transceivers; One or more of the above processors: Within a transmit opportunity (TXOP) duration of the second STA, transmitting a first frame including information indicating the presence of traffic to be transmitted from the first STA to the second STA via the one or more transceivers; and A device configured to transmit, after transmitting the first frame, a second frame including the traffic to the second STA via the one or more transceivers.

16. A step of receiving a first frame from a first STA by a second station (STA), the first frame including information indicating the presence of traffic to be transmitted from the first STA within a transmission opportunity (TXOP) duration of the second STA; and A method comprising the step of receiving, by the second STA, a second frame including the traffic from the first STA after receiving the first frame.

17. One or more transmitters / receivers; and comprising one or more processors coupled to said one or more transceivers; One or more of the above processors: Within a transmit opportunity (TXOP) duration of a second station (STA), receiving a first frame from the first STA via the one or more transceivers, the first frame including information indicating the presence of traffic to be transmitted from the first STA; and A device configured to receive, after receiving the first frame, a second frame including the traffic from the first STA via the one or more transceivers.

18. One or more processors; and A processing unit comprising one or more computer memories operatively connected to said one or more processors and storing instructions for performing a method according to any one of claims 1 to 14 based on execution by said one or more processors.

19. One or more non-transitory computer-readable media storing one or more instructions that are executed by one or more processors to perform a method according to any one of claims 1 to 14.

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