Method and apparatus for performing relay transmission during triggered transmission opportunity in wireless LAN system

Abstract

Disclosed are a method and an apparatus for performing relay transmission during a triggered transmission opportunity in a wireless LAN system. According to one embodiment of the present disclosure, a method performed by means of a first station (STA) in a wireless LAN system comprises the steps of: receiving, from an access point (AP), a first A-MPDU including data to be transmitted to a second STA; an ACK frame for the first A-MPDU is sent to the AP; and transmitting a second A-MPDU including the data to a second STA. Here, the ACK frame includes ACK information indicating whether to acknowledge at least one MAC header included in the first A-MPDU, and the ACK information may be based on an ACK policy indicated by an ACK policy related field and at least one other field included in the first A-MPDU.

Description

Technical Field

[0001] The present disclosure relates to a method and apparatus for performing relay transmission at a triggered transmission opportunity (triggered TXOP) in a wireless local area network (WLAN) system. Background Art

[0002] New technologies have been introduced for wireless LANs (WLANs) to increase transmission rates, increase bandwidth, improve reliability, reduce errors, and reduce latency. Among WLAN technologies, the Institute of Electrical and Electronics Engineers (IEEE) 802.11 series of standards can be referred to as Wi-Fi. For example, recent technologies introduced to WLANs include the Very High Throughput (VHT) enhancements of the 802.11ac standard and the High Efficiency (HE) enhancements of 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 MIMO and multi-access point (AP) coordination that support increased bandwidth, efficient utilization of multiple frequency bands, and increased spatial streams are being studied. Specifically, various technologies are being studied to support low-latency or real-time services. Furthermore, new technologies are being discussed to support Ultra-High Reliability (UHR), including improvements or extensions to EHT technologies. Summary of the Invention

[0004] Technical issues

[0005] A technical objective of the present disclosure is to provide a method and apparatus for performing relay transmission at a triggered transmission opportunity (triggered TXOP) in a wireless local area network (WLAN) system.

[0006] The technical objectives to be achieved by the present disclosure are not limited to the above-mentioned technical objectives, and those skilled in the art can clearly understand other technical objectives not described herein through the following description.

[0007] Technical Solution

[0008] According to one aspect of the present disclosure, a method performed by a first station (STA) in a wireless LAN system may include: receiving a first aggregate MAC protocol data unit (A-MPDU) including data to be transmitted to a second STA from an access point (AP); transmitting an acknowledgment (ACK) frame for the first A-MPDU to the AP; and transmitting a second A-MPDU including the data to the second STA. The ACK frame may include ACK information indicating whether at least one MAC header included in the first A-MPDU was checked, and the ACK information may be based on an ACK policy indicated by an ACK policy-related field and at least one other field included in the first A-MPDU.

[0009] According to another aspect of the present disclosure, a method performed by an access point (AP) in a wireless LAN system may include: transmitting an aggregated MAC protocol data unit (A-MPDU) including data to be transmitted to a second STA to a first station (STA); and receiving an acknowledgment (ACK) frame for the A-MPDU from the first STA. Here, the ACK frame may include ACK information indicating whether at least one MAC header included in the A-MPDU was checked, and the ACK information may be based on an ACK policy indicated by an ACK policy-related field and at least one other field included in the A-MPDU.

[0010] Technical Effects

[0011] According to the present disclosure, a method and apparatus for performing relay transmission at a triggered transmission opportunity (triggered TXOP) in a wireless local area network (WLAN) system may be provided.

[0012] According to the present disclosure, it is possible to provide effects of range extension and throughput improvement through a relay method in a wireless LAN system.

[0013] Effects achievable by the present disclosure are not limited to the above-described effects, and other effects not described herein may be clearly understood by those skilled in the relevant art through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The accompanying drawings, which are included as a part of the detailed description for understanding the present disclosure, provide embodiments of the present disclosure and describe technical features of the present disclosure together with the detailed description.

[0015] Figure 1 A block diagram illustrating a configuration of a wireless communication device according to an embodiment of the present disclosure is illustrated.

[0016] Figure 2 is a diagram illustrating an exemplary structure of a WLAN system to which the present disclosure can be applied.

[0017] Figure 3 is a diagram for explaining a link establishment process to which the present disclosure can be applied.

[0018] Figure 4 is a diagram for explaining a backoff process to which the present disclosure can be applied.

[0019] Figure 5 is a diagram for explaining a CSMA / CA-based frame transmission operation to which the present disclosure may be applied.

[0020] Figure 6is a diagram for explaining an example of a frame structure used in a WLAN system to which the present disclosure can be applied.

[0021] Figure 7 is a diagram illustrating an example of a PPDU defined in the IEEE 802.11 standard to which the present disclosure can be applied.

[0022] Figure 8 is a diagram illustrating an exemplary format of a trigger frame to which the present disclosure can be applied.

[0023] Figure 9 is a diagram for explaining an example of a triggered TXOP sharing procedure to which the present disclosure can be applied.

[0024] Figure 10 An example of a relay transmission process according to an embodiment of the present disclosure is illustrated.

[0025] Figure 11 Another example of the relay transmission process according to an embodiment of the present disclosure is illustrated.

[0026] Figure 12 A flowchart illustrating operations performed by a first STA according to an embodiment of the present disclosure is illustrated.

[0027] Figure 13 A flowchart illustrating operations performed by an AP according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0028] Hereinafter, embodiments according to the present disclosure will be described in detail with reference to the accompanying drawings. The detailed description disclosed with the accompanying drawings is intended to describe exemplary embodiments of the present disclosure and is not intended to represent the only embodiment in which the present disclosure may be implemented. The following detailed description includes specific details to provide a complete understanding of the present disclosure. However, those skilled in the relevant art will appreciate that the present disclosure may be implemented without these specific details.

[0029] In some cases, well-known structures and devices may be omitted, or may be shown in the form of block diagrams based on the core functions of each structure and device in order to prevent ambiguity in the concepts of the present disclosure.

[0030] In the present disclosure, when an element is referred to as being "connected," "combined," or "linked" to another element, it may include an indirect connection relationship in which another element exists therebetween as well as a direct connection relationship. In addition, in the present disclosure, the terms "comprising" or "having" specify the presence of the mentioned features, steps, operations, components, and / or elements, but do not preclude the presence or addition of one or more other features, steps, operations, components, elements, and / or groups thereof.

[0031] In the present disclosure, terms such as "first," "second," etc. are used only to distinguish one element from another and are not used to limit the elements. Unless otherwise specified, they do not limit the order or importance of the elements. Therefore, within the scope of the present disclosure, the first element in one embodiment may be referred to as the second element in another embodiment, and similarly, the second element in one embodiment may be referred to as the first element in another embodiment.

[0032] The terms used in this disclosure are intended to describe specific embodiments and not to limit the claims. As used in the description of the embodiments and the appended claims, the singular is intended to include the plural, unless the context clearly indicates otherwise. The term "and / or" used in this disclosure may refer to one of the relevant enumerated items, or mean that it refers to and includes any and all possible combinations of two or more of them. In addition, unless otherwise indicated, the " / " between words in this disclosure has the same meaning as "and / or".

[0033] Examples of the present disclosure can be applied to various wireless communication systems. For example, examples of the present disclosure can be applied to wireless LAN systems. For example, examples of the present disclosure can be applied to wireless LANs based on IEEE 802.11a / g / n / ac / ax standards. In addition, examples of the present disclosure can be applied to wireless LANs based on the newly proposed IEEE 802.11be (or EHT) standard. Examples of the present disclosure can be applied to wireless LANs based on the IEEE802.11be version 2 standard corresponding to the additional enhanced technology of the IEEE 802.11be version 1 standard. In addition, examples of the present disclosure can be applied to wireless LANs based on the next generation standard after IEEE 802.11be. In addition, examples of the present disclosure can be applied to cellular wireless communication systems. For example, it can be applied to cellular wireless communication systems based on long term evolution (LTE) technology and 5G new radio (NR) technology based on the third generation partnership project (3GPP) standard.

[0034] Hereinafter, technical features of examples to which the present disclosure can be applied will be described.

[0035] Figure 1 A block diagram of a wireless communication device according to an embodiment of the present disclosure is illustrated.

[0036] Figure 1The first device 100 and the second device 200 illustrated in the specification may be replaced with various terms such as a terminal, a wireless device, a wireless transmit / receive unit (WTRU), a user equipment (UE), a mobile station (MS), a user terminal (UT), a mobile subscriber station (MSS), a mobile subscriber unit (MSU), a subscriber station (SS), an advanced mobile station (AMS), a wireless terminal (WT), or a simple user. In addition, the first device 100 and the second device 200 include an access point (AP), a base station (BS), a fixed station, a node B, a base transceiver system (BTS), and a network. It may be replaced with various terms such as an artificial intelligence (AI) system, a roadside unit (RSU), a repeater, a router, a relay, and a gateway.

[0037] Figure 1 The devices 100 and 200 illustrated in FIG. 1 may be referred to as stations (STAs). Figure 1 The devices 100 and 200 illustrated in the accompanying drawings may be referred to by various terms such as a transmitting device, a receiving device, a transmitting STA, and a receiving STA. For example, the STAs 110 and 200 may perform an access point (AP) role or a non-AP role. That is, in the present disclosure, the STAs 110 and 200 may perform AP and / or non-AP functions. When the STAs 110 and 200 perform AP functions, they may be simply referred to as APs, and when the STAs 110 and 200 perform non-AP functions, they may be simply referred to as STAs. In addition, in the present disclosure, an AP may also be referred to as an AP STA.

[0038] Reference Figure 1 , the first device 100 and the second device 200 can transmit and receive radio 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 media access control (MAC) layer and a physical layer (PHY) that conform to the IEEE 802.11 standard.

[0039] In addition to wireless LAN technology, the first device 100 and the second device 200 can also support various communication standards (e.g., 3GPP LTE series, 5G NR series standards, etc.). In addition, the device of the present disclosure can be implemented in various devices such as mobile phones, vehicles, personal computers, augmented reality (AR) devices, and virtual reality (VR) devices. In addition, the STA of this specification can support various communication services such as voice calls, video calls, data communications, autonomous driving, machine type communication (MTC), machine-to-machine (M2M), device-to-device (D2D), IoT (Internet of Things), etc.

[0040] The first device 100 may include 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 may control the memory 104 and / or the transceiver 106 and may be configured to implement the descriptions, functions, processes, suggestions, methods, and / or operational flowcharts included in this disclosure. For example, the processor 102 may generate first information / signals by processing information in the memory 104 and then transmit a wireless signal including the first information / signals via the transceiver 106. Alternatively, the processor 102 may receive a wireless signal including second information / signals via the transceiver 106 and then store information obtained through 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 store software code including instructions for executing all or part of the processing controlled by the processor 102 or for executing the descriptions, functions, processes, suggestions, methods, and / or operational flowcharts included in this disclosure. Here, the processor 102 and the memory 104 may be part of a communication modem / circuit / chip designed to implement wireless LAN technology (e.g., the 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 in conjunction with an RF (radio frequency) unit. In the present disclosure, a wireless device may refer to a communication modem / circuit / chip.

[0041] The second device 200 may include one or more processors 202 and one or more memories 204, and may further include one or more transceivers 206 and / or one or more antennas 208. The processor 202 may control the memory 204 and / or the transceiver 206 and may be configured to implement the descriptions, functions, processes, suggestions, methods, and / or operational flowcharts included in this disclosure. For example, the processor 202 may generate third information / signals by processing information in the memory 204, and then transmit a wireless signal including the third information / signals via the transceiver 206. Alternatively, the processor 202 may receive a wireless signal including fourth information / signals via the transceiver 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 store software code including instructions for executing all or part of the processing controlled by the processor 202 or for executing the descriptions, functions, processes, suggestions, methods, and / or operational flowcharts included in this disclosure. Here, the processor 202 and the memory 204 may be part of a communication modem / circuit / chip designed to implement wireless LAN technology (e.g., the 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 in conjunction with an RF unit. In the present disclosure, a device may refer to a communication modem / circuit / chip.

[0042] In the following, the hardware elements of the apparatus 100, 200 will be described in more detail. Without limitation, 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 PDUs (Protocol Data Units) and / or one or more SDUs (Service Data Units) according to the descriptions, functions, processes, suggestions, 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, processes, suggestions, methods, and / or operational flowcharts disclosed in the present disclosure. One or more processors 102, 202 may generate signals (e.g., baseband signals) including PDUs, SDUs, messages, control information, data, or information according to the functions, processes, suggestions, and / or methods disclosed in the present disclosure to provide them to one or more transceivers 106, 206. One or more processors 102, 202 may 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, processes, suggestions, methods, and / or operational flow diagrams included in the present disclosure.

[0043] The one or more processors 102, 202 may be referred to as controllers, microcontrollers, microprocessors, or microcomputers. The one or more processors 102, 202 may be implemented by hardware, firmware, software, or a combination thereof. For example, one or more ASICs (Application Specific Integrated Circuits), one or more DSPs (Digital Signal Processors), one or more DSPDs (Digital Signal Processing Devices), one or more PLDs (Programmable Logic Devices), or one or more FPGAs (Field Programmable Gate Arrays) may be included in the one or more processors 102, 202. The descriptions, functions, processes, suggestions, methods, and / or operational flowcharts included in the present disclosure may be implemented using firmware or software, and the firmware or software may be implemented to include modules, processes, functions, etc. The firmware or software configured to execute the descriptions, functions, processes, suggestions, methods, and / or operational flowcharts included in the present disclosure may be included in the one or more processors 102, 202, or may be stored in one or more memories 104, 204 and driven by the one or more processors 102, 202. The descriptions, functions, processes, suggestions, methods and / or operational flow charts included in the present disclosure may be implemented using firmware or software in the form of codes, instructions and / or instruction sets.

[0044] One or more memories 104, 204 can be connected to one or more processors 102, 202 and can store data, signals, messages, information, programs, codes, instructions, and / or commands in various forms. One or more memories 104, 204 can be configured with ROM, RAM, EPROM, flash memory, hard drive, registers, cache memory, computer-readable storage media, and / or combinations thereof. One or more memories 104, 204 can be located internally and / or externally to one or more processors 102, 202. In addition, one or more memories 104, 204 can be connected to one or more processors 102, 202 via various technologies such as wired or wireless connections.

[0045] One or more transceivers 106, 206 may transmit user data, control information, wireless signals / channels, etc., as described in the methods and / or operational flowcharts, etc., of the present disclosure to one or more other devices. One or more transceivers 106, 206 may receive user data, control information, wireless signals / channels, etc., as described, functions, processes, suggestions, methods, and / or operational flowcharts, etc., included in the present disclosure from one or more other devices. For example, one or more transceivers 106, 206 may be connected to one or more processors 102, 202 and may transmit and receive wireless signals. For example, one or more processors 102, 202 may control one or more transceivers 106, 206 to transmit user data, control information, or wireless signals to one or more other devices. In addition, 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. In addition, one or more transceivers 106, 206 may be connected 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, etc. mentioned in the descriptions, functions, processes, suggestions, methods, and / or operational flowcharts, etc. included in the present disclosure through 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 may convert received wireless signals / channels, etc. from RF band signals into baseband signals to process the received user data, control information, wireless signals / channels, etc. by 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 using one or more processors 102, 202 from baseband signals into RF band signals. Thus, one or more transceivers 106 , 206 may include (analog) oscillators and / or filters.

[0046] For example, one of the STAs 100 and 200 may perform the intended operation of an AP, and the other of the STAs 100 and 200 may perform the intended operation of a non-AP STA. Figure 1 The transceivers 106 and 206 can perform signal transmission and reception operations (e.g., packets or physical layer protocol data units (PPDUs) compliant with IEEE 802.11a / b / g / n / ac / ax / be / bn). In addition, in the present disclosure, operations of various STAs generating transmission / reception signals or performing data processing or calculations on transmission / reception signals in advance can be performed by Figure 1The processors 102 and 202 of the STA may execute the operations of generating a transmit / receive signal or performing data processing or calculation for the transmit / receive signal in advance. For example, examples of operations of generating a transmit / receive signal or performing data processing or calculation for the transmit / receive signal in advance may include: 1) determining / acquiring / configuring / calculating / decoding / encoding bit information of fields (signal (SIG), short training field (STF), long training field (LTF), data, etc.) included in the PPDU; 2) determining / configuring / acquiring time resources or frequency resources (e.g., subcarrier resources) used for fields (SIG, STF, LTF, data, etc.) included in the PPDU; 3) determining / configuring / acquiring specific sequences (e.g., pilot sequences, STF / LTF sequences, additional sequences applied to SIG) for fields (SIG, STF, LTF, data, etc.) included in the PPDU action; 4) power control operations and / or power saving operations applied to STAs; 5) operations related to determining / acquiring / configuring / calculating / decoding / encoding of ACK signals, etc. In addition, in the following example, various information used by various STAs to determine / acquire / configure / calculate / decode / encode transmission signals and reception signals (e.g., information related to fields / subfields / control fields / parameters / power, etc.) may be stored in Figure 1 in memories 104 and 204.

[0047] Hereinafter, the downlink (DL) may refer to a link used for communication from an AP STA to a non-AP STA, and DL PPDUs / packets / signals may be transmitted and received via the DL. In DL communication, the transmitter may be part of an AP STA, and the receiver may be part of a non-AP STA. The uplink (UL) may refer to a link used for communication from a non-AP STA to an AP STA, and UL PPDUs / packets / signals may be transmitted and received via the UL. In UL communication, the transmitter may be part of a non-AP STA, and the receiver may be part of an AP STA.

[0048] Figure 2 is a diagram illustrating an exemplary structure of a wireless LAN system to which the present disclosure can be applied.

[0049] The structure of a wireless LAN system can be composed of multiple components. The interaction of multiple components can provide a wireless LAN that supports STA mobility that is transparent to upper layers. The basic service set (BSS) corresponds to the basic building block of a wireless LAN. Figure 2 It is exemplarily shown that two BSSs (BSS1 and BSS2) exist, and two STAs are included as members of each BSS (STA1 and STA2 are included in BSS1, and STA3 and STA4 are included in BSS2). Figure 2The ellipse representing the BSS in the figure can also be understood as representing the coverage area in which the STAs included in the corresponding BSS maintain communication. This area can be called the basic service area (BSA). When a STA moves outside the BSA, it cannot communicate directly with other STAs in the BSA.

[0050] If you don't consider Figure 2 , the most basic BSS type in a wireless LAN is an independent BSS (IBSS). For example, an IBSS may have a minimum form containing only two STAs. For example, assuming that other components are omitted, BSS1 containing only STA1 and STA2 or BSS2 containing only STA3 and STA4 may correspond to representative examples of IBSSs, respectively. This configuration is possible when STAs can communicate directly without an AP. In addition, in this type of wireless LAN, it is not pre-configured but can be configured when a LAN is needed, and this may be referred to as an ad-hoc network. Since the 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 an IBSS, all STAs may be composed of mobile STAs, and access to the distributed system (DS) is not allowed, thereby forming a self-contained network.

[0051] The membership of a STA in a BSS can be changed dynamically by turning the STA on or off, entering or exiting a BSS region, etc. To become a member of a BSS, a STA can join the BSS using a synchronization process. To access all services of the BSS infrastructure, a STA must associate with the BSS. This association can be established dynamically and can include the use of a distributed system service (DSS).

[0052] The direct STA-to-STA distance in a wireless LAN may be limited by PHY performance. In some cases, this distance limit may be sufficient, but in some cases, communication between STAs at longer distances may be required. A distributed system (DS) can be configured to support extended coverage.

[0053] DS refers to the structure of BSS interconnection. Specifically, Figure 2As shown, the BSS can exist as an extended form of a network composed of multiple BSSs. DS is a logical concept and can be specified by the characteristics of the distributed system medium (DSM). At this point, the wireless medium (WM) and the DSM can be logically separated. Each logical medium is used for a different purpose and is used by different components. These media are not limited to being the same, nor are they limited to being different. In this way, the flexibility of the wireless LAN structure (DS structure or other network structure) can be interpreted as multiple media being logically different. That is, the wireless LAN structure can be implemented in various ways, and the corresponding wireless LAN structure can be independently specified by the physical characteristics of each embodiment.

[0054] DS can support mobile devices by providing seamless integration of multiple BSSs and providing the logical services necessary to address the address leading to the destination. In addition, DS can also include a component called a portal, which is used as a bridge for connections between wireless LANs and other networks (e.g., IEEE 802.X).

[0055] The AP enables associated non-AP STAs to access the DS through the WM and means an entity that also has STA functionality. Data movement between the BSS and the DS can be performed through the AP. For example, Figure 2 STA2 and STA3 shown in the figure have STA functionality and provide functionality allowing associated non-AP STAs (STA1 and STA4) to access the DS. Furthermore, since all APs essentially correspond to STAs, all APs are addressable entities. The addresses used by APs for communication on the WM are not necessarily the same as the addresses used by APs for communication on the DSM. A BSS consisting of an AP and one or more STAs may be referred to as an infrastructure BSS.

[0056] Data sent from one of the STAs associated with the AP to the STA address of the corresponding AP can always be received at the uncontrolled port and can be processed by the IEEE 802.1X port access entity. In addition, when the controlled port is authenticated, the transmitted data (or frame) can be delivered to the DS.

[0057] In addition to the above-mentioned structure of the DS, an extended service set (ESS) can also be configured to provide wide coverage.

[0058] An ESS refers to a network of arbitrary size and complexity consisting of a DS and a BSS. An ESS may correspond to a set of BSSs connected to one DS. However, an ESS does not include a DS. An ESS network is characterized by being considered an IBSS in the Logical Link Control (LLC) layer. STAs included in 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 included in an ESS may have the same service set identifier (SSID). The SSID is distinguished from the BSSID, which is an identifier of a BSS.

[0059] The wireless LAN system does not assume anything about the relative physical location of the BSSs, and all of the following forms are possible. BSSs can partially overlap, which is a form commonly used to provide continuous coverage. In addition, BSSs may not be physically connected, and logically, there is no limit on the distance between BSSs. In addition, BSSs can be physically located in the same location, which can be used to provide redundancy. In addition, one (or more than one) IBSS or ESS networks can physically exist in the same space as one (or more than one) ESS networks. When an ad hoc network operates in a location where an ESS network exists, when physically overlapping wireless networks are configured by different organizations, or when two or more different access and security policies are required in the same location, this can correspond to the form of an ESS network, etc.

[0060] Figure 3 is a diagram for explaining a link establishment process to which the present disclosure can be applied.

[0061] In order for a STA to establish a link with the network and send / receive data, it first discovers the network, performs authentication, establishes an association, and, for security reasons, performs authentication processing. The link establishment process may also be referred to as the session initiation process or the session establishment process. Furthermore, the discovery, authentication, association, and security establishment processes of the link establishment process may be collectively referred to as the association process.

[0062] In step S310, the STA may perform a network discovery operation. The network discovery operation may include a scanning operation by the STA. In other words, in order for the STA to access the network, it needs to find a network it can participate in. The STA should identify compatible networks before participating in a wireless network, and the process of identifying networks existing in a specific area is called scanning.

[0063] Scanning schemes include active scanning and passive scanning. Figure 3The network discovery operation including the active scanning process is exemplarily illustrated. In active scanning, the STA performing the scan sends a probe request frame to discover which APs exist around it while moving through the channel and waits for responses thereto. The responder sends a probe response frame as a response to the probe request frame to the STA that has sent the probe request frame. Here, the responder may be the STA that last sent a beacon frame in the BSS of the channel being scanned. In the BSS, since the AP sends a beacon frame, the AP becomes the responder, and in the IBSS, the STAs in the IBSS rotate to send beacon frames, so the responder is not constant. For example, a STA that sends a probe request frame on channel 1 and receives a probe response frame on channel 1 can store the BSS-related information included in the received probe response frame, and can move to the next channel (e.g., channel 2) and perform scanning in the same manner (i.e., sending and receiving probe requests / responses on channel 2).

[0064] Although not in Figure 3 Although not shown in FIG, a scanning operation can be performed in a passive scanning manner. In passive scanning, a scanning STA waits for a beacon frame while moving across channels. A beacon frame is one of the management frames defined in IEEE 802.11 and is periodically transmitted to notify the existence of a wireless network and allow a scanning STA to find and participate in the wireless network. In a BSS, an AP is used to periodically transmit beacon frames, and in an IBSS, STAs within the IBSS rotate to transmit beacon frames. When a scanning STA receives a beacon frame, the STA stores the BSS information included in the beacon frame and, while moving to another channel, records the beacon frame information in each channel. The STA that receives the beacon frame can store the BSS-related information included in the received beacon frame, move to the next channel, and perform scanning in the next channel in the same manner. Comparing active scanning with passive scanning, the advantage of active scanning is that it has less latency and consumes less power than passive scanning.

[0065] After the STA discovers the network, an authentication process may be performed at step S320. In order to clearly distinguish it from the security establishment operation of step S340 to be described later, this authentication process may be referred to as a first authentication process.

[0066] The authentication process includes the following process: the STA sends an authentication request frame to the AP, and in response thereto, the AP sends an authentication response frame to the STA. The authentication frame used for authentication request / response corresponds to a management frame.

[0067] The authentication frame includes an authentication algorithm number, an authentication transaction sequence number, a status code, a challenge text, a robust security network (RSN), a limited cycle group, etc. This corresponds to some examples of information that can be included in the authentication request / response frame, and can be replaced with other information, or additional information can be included.

[0068] The STA may send an authentication request frame to the AP. The AP may determine whether to allow authentication of the corresponding STA based on the information included in the received authentication request frame. The AP may provide the result of the authentication process to the STA via an authentication response frame.

[0069] After the STA is successfully authenticated, an association process may be performed at step S330. The association process includes the following processes: the STA sends an association request frame to the AP, and in response, the AP sends an association response frame to the STA.

[0070] For example, the association request frame may include information related to various capabilities, a beacon listening interval, a service set identifier (SSID), supported rates, supported channels, RSN, mobility domain, supported operation categories, a traffic indication map broadcast request (TIM broadcast request), interworking service capabilities, etc. For example, the association response frame may include information related to 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 ratio indicator (RSNI), mobility domain, a timeout interval (e.g., association recovery time), overlapping BSS scan parameters, a TIM broadcast response, a quality of service (QoS) map, etc. This corresponds to some examples of information that may be included in the association request / response frame and may be replaced with other information or may further include additional information.

[0071] After the STA successfully associates with the network, a security establishment process may be performed at step S340. The security establishment process at step S340 may be referred to as an authentication process through a Robust Security Network Association (RSNA) request / response, the authentication process at step S320 may be referred to as a first authentication process, and the security establishment process at step S340 may also be referred to simply as an authentication process.

[0072] The security establishment process of step S340 may include, for example, a process of establishing a private key using a four-way handshake through an Extensible Authentication Protocol over LAN (EAPOL) frame. Alternatively, the security establishment process may be performed according to a security scheme not defined in the IEEE 802.11 standard.

[0073] Figure 4 It is a diagram for explaining a backoff process to which the present disclosure can be applied.

[0074] In wireless LAN systems, the basic access mechanism for medium access control (MAC) is the Carrier Sense Multiple Access with Collision Avoidance (CSMA / CA) mechanism. The CSMA / CA mechanism is also known as the Distributed Coordination Function (DCF) of the IEEE 802.11 MAC and essentially employs a "listen before talk" access mechanism. According to this type of access mechanism, before starting transmission, the AP and / or STA may perform Explicit Channel Assessment (CCA) to sense the radio channel or medium during a predetermined time interval (e.g., the DCF Interframe Space (DIFS)). As a result of this sensing, if the medium is determined to be idle, frame transmission is initiated via the corresponding medium. On the other hand, if the medium is detected to be occupied or busy, the corresponding AP and / or STA does not initiate its own transmission and may set a delay period for medium access (e.g., a random backoff period) and attempt frame transmission after the wait. By applying a random backoff period, collisions can be minimized because multiple STAs are expected to attempt frame transmission after waiting for different time periods.

[0075] In addition, the IEEE 802.11 MAC protocol provides a hybrid coordination function (HCF). HCF is based on DCF and point coordination function (PCF). PCF is a synchronous access method based on polling, and refers to a method in which all receiving APs and / or STAs periodically poll to receive data frames. In addition, HCF has enhanced distributed channel access (EDCA) and HCF controlled channel access (HCCA). EDCA is a contention-based access method that provides data frames to multiple users in a direction, and HCCA uses a non-contention-based channel access method that utilizes a polling mechanism. In addition, HCF includes a medium access mechanism for improving the QoS (quality of service) of a wireless LAN, and QoS data can be sent in a contention period (CP) and a contention-free period (CFP).

[0076] Reference Figure 4, the operation based on the random backoff period will be described. When the occupied / busy medium becomes idle, multiple STAs can attempt to send data (or frames). As a method of minimizing collisions, each of the STAs can select a random backoff count respectively and attempt to send after waiting for the corresponding time slot time. The random backoff count has a pseudo-random integer value and can be determined as one of the values ranging from 0 to CW. Here, CW is the contention window parameter value. The CW parameter is given CWmin as an initial value, but can take a value twice as large in the event of a transmission failure (for example, when an ACK for the transmitted frame is not received). When the CW parameter value reaches CWmax, data transmission can be attempted while maintaining the CWmax value until the data transmission is successful, and when the data transmission is successful, the CWmin value is reset. The values of CW, CWmin and CWmax are preferably set to 2n-1 (n=0, 1, 2, ...).

[0077] When the random backoff process starts, the STA continuously monitors the medium during the backoff slot countdown according to the determined backoff count value. When the medium is monitored for occupancy, it stops the countdown and waits, and restarts the remaining countdown when the medium becomes idle.

[0078] exist Figure 4 In the example shown, when a packet to be transmitted arrives at STA3's MAC, STA3 can immediately transmit a frame after confirming that the medium has been idle for DIFS. The remaining STAs monitor and wait for the medium to become occupied / busy. Meanwhile, data to be transmitted can also occur at each of STA1, STA2, and STA5. When the medium is detected as idle, each STA waits for DIFS and then begins counting down the backoff slot based on a random backoff count value selected by each STA. Assume that STA2 selects the minimum backoff count value and STA1 selects the maximum backoff count value. This example illustrates a situation where, when STA2 completes the backoff count and begins frame transmission, STA5's remaining backoff time is shorter than STA1's. STA1 and STA5 temporarily stop the countdown 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 restart the backoff count where they left off. This means that frame transmission can begin after counting down the remaining backoff slots for the remaining backoff time. Since STA5's remaining backoff time is shorter than STA1's, STA5 begins frame transmission. While STA2 is occupying the medium, data transmission can also occur in STA4. From STA4's perspective, when the medium becomes idle, STA4 can wait for DIFS, then perform a countdown based on a random backoff count value selected by STA4 and begin frame transmission. Figure 4The example shows a situation where STA5's remaining backoff time accidentally conflicts with STA4's random backoff count value. In this case, a collision may occur between STA4 and STA5. When a collision occurs, neither STA4 nor STA5 receives an ACK, and data transmission fails. In this case, STA4 and STA5 can double the CW value, select a random backoff count value, and perform a countdown. While the medium is occupied by STA4 and STA5's transmissions, STA1 waits. When the medium becomes idle, STA1 waits DIFS and then begins frame transmission after the remaining backoff time has elapsed.

[0079] As in Figure 4 In the example, a data frame is a frame used to transmit data forwarded to a higher layer and can be transmitted after a backoff is performed after a DIFS period has elapsed since the medium became idle. Furthermore, a management frame is a frame used to exchange management information that is not forwarded to a higher layer and is transmitted after a backoff is performed after an IFS period, such as a DIFS period or a Point Coordination Function (PIFS) period. Subtypes of management frames include beacons, association request / responses, reassociation request / responses, probe request / responses, and authentication request / responses. Control frames are frames used to control access to the medium. Subtypes of control frames include request to send (RTS), clear to send (CTS), acknowledgement (ACK), power save poll (PS-Poll), block ACK (BlockAck), block ACK request (BlockACKReq), null data packet announcement (NDP announcement), and triggers. If a control frame is not a response frame to the previous frame, it is transmitted after a backoff is performed after a DIFS period has elapsed. If it is a response frame to the previous frame, it is transmitted without a backoff after a short IFS period (SIFS) has elapsed. The type and subtype of a frame may be identified by the type field and subtype field in the frame control (FC) field.

[0080] A Quality of Service (QoS) STA can perform a backoff after the arbitration IFS (AIFS) for the access category (AC) to which the frame belongs (i.e., AIFS (where i is a value determined by the AC)) and then transmit the frame. Here, frames that can use AIFS may be data frames, management frames, or control frames, rather than response frames.

[0081] Figure 5 is a diagram for explaining a frame transmission operation based on CSMA / CA to which the present disclosure can be applied.

[0082] As described above, in addition to the physical carrier sensing in which the STA directly senses the medium, the CSMA / CA mechanism also includes virtual carrier sensing. Virtual carrier sensing is intended to compensate for problems such as hidden node problems that may occur in medium access. For virtual carrier sensing, the STA's MAC can use a network allocation vector (NAV). NAV is a value that indicates to other STAs the remaining time until the medium is available for use by the STA that is currently using or has the right to use the medium. Therefore, the value set to NAV corresponds to the period during which the STA sending the frame plans to use the medium, and during the corresponding period, the STA that receives the NAV value is prohibited from accessing the medium. For example, NAV can be configured based on the value of the "Duration" field of the MAC header of the frame.

[0083] exist Figure 5 In the example of FIG, it is assumed that STA1 intends to send data to STA2, and STA3 is in a position to be able to eavesdrop on some or all frames sent and received between STA1 and STA2.

[0084] In order to reduce the possibility of transmission collisions between multiple STAs in the CSMA / CA-based frame transmission operation, a mechanism using RTS / CTS frames can be applied. Figure 5 In the example of , when STA1 is transmitting, as a result of STA3's carrier sensing, it can be determined that the medium is in an idle state. That is, STA1 may correspond to a hidden node with respect to STA3. Alternatively, in Figure 5 In the example shown in FIG1 , it can be determined that the medium is idle based on STA3's carrier sensing result while STA2 is transmitting. In other words, STA2 may correspond to a hidden node with respect to STA3. By exchanging RTS / CTS frames before data transmission and reception between STA1 and STA2, STAs outside the transmission range of either STA1 or STA2, or outside the carrier sensing range of STA1 or STA3's transmission, can avoid attempting to occupy the channel during data transmission and reception between STA1 and STA2.

[0085] Specifically, STA1 can determine whether a channel is in use through carrier sensing. In terms of physical carrier sensing, STA1 can determine the channel occupancy idle state based on the energy level or signal correlation detected in the channel. In addition, in terms of virtual carrier sensing, STA1 can use the network allocation vector (NAV) timer to determine the channel occupancy state.

[0086] When the channel is idle for DIFS, STA1 may send an RTS frame to STA2 after backoff. When STA2 receives the RTS frame, STA2 may send a CTS frame to STA1 as a response to the RTS frame after SIFS.

[0087] If STA3 cannot overhear a CTS frame from STA2 but can overhear an RTS frame from STA1, STA3 can use the duration information included in the RTS frame to set the NAV timer for the subsequent frame transmission period (e.g., SIFS + CTS frame + SIFS + data frame + SIFS + ACK frame). Alternatively, if STA3 can overhear a CTS frame from STA2, even if STA3 cannot overhear an RTS frame from STA1, STA3 can use the duration information included in the CTS frame to set the NAV timer for the subsequent frame transmission period (e.g., SIFS + data frame + SIFS + ACK frame). In other words, if STA3 can overhear one or more of the RTS or CTS frames from one or more of STA1 or STA2, STA3 can set the NAV accordingly. When STA3 receives a new frame before the NAV timer expires, STA3 can update the NAV timer using the duration information included in the new frame. STA3 does not attempt channel access until the NAV timer expires.

[0088] When STA1 receives a CTS frame from STA2, STA1 can send a data frame to STA2 after SIFS, starting from the time when the CTS frame is received. When STA2 successfully receives the data frame, STA2 can send an ACK frame to STA1 after SIFS as a response to the data frame. When the NAV timer expires, STA3 can determine whether the channel is in use through carrier sensing. If STA3 determines that the channel is not being used by other terminals during the DIFS period after the NAV timer expires, STA3 can attempt channel access after the contention window (CW) based on random backoff has expired.

[0089] Figure 6 is a diagram for explaining an example of a frame structure used in a WLAN system to which the present disclosure can be applied.

[0090] The PHY layer can prepare the MAC PDU (MPDU) to be transmitted with the help of instructions or primitives (meaning a set of instructions or parameters) from the MAC layer. For example, when a command requesting the PHY layer to start transmission is received from the MAC layer, the PHY layer switches to transmit mode, configures the information provided by the MAC layer (e.g., data) in the form of a frame, and transmits it. In addition, when the PHY layer detects a valid preamble of the received frame, the PHY layer monitors the header of the preamble and sends a command to the MAC layer to notify the PHY layer of the start of reception.

[0091] In this manner, information transmission / reception in the wireless LAN system is performed in the form of frames, and for this purpose, a PHY layer protocol data unit (PPDU) format is defined.

[0092] The basic PPDU may include a short training field (STF), a long training field (LTF), a signal (SIG) field, and a data (Data) field. Figure 7 The non-HT (high throughput) field shown in FIG may consist only of the legacy-STF (L-STF), legacy-LTF (L-LTF), legacy-SIG (L-SIG) field, and the data field. In addition, depending on the type of PPDU format (e.g., HT mixed format PPDU, HT greenfield format PPDU, VHT (very high throughput) PPDU, etc.), an additional (or different type) 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.

[0093] STF is a signal used for signal detection, automatic gain control (AGC), diversity selection, precise time synchronization, etc., and LTF is a signal used for channel estimation and frequency error estimation. STF and LTF can be called signals for synchronization and channel estimation of the OFDM physical layer.

[0094] The SIG field may include various information related to PPDU transmission and reception. For example, the L-SIG field consists 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 the data. For example, the 12-bit length field may include information about the length or duration of the PPDU. For example, the value of the 12-bit length field may be determined based on the type of PPDU. For example, for non-HT, HT, VHT, or EHT PPDUs, the value of the length field may be determined as a multiple of 3. For example, for HEPPDUs, the value of the length field may be determined as a multiple of 3+1 or 3+2.

[0095] The data field may include a service (SERVICE) field, a physical layer service data unit (PSDU), and a PPDU tail bit, and may also include padding bits if necessary. Some bits of the service field may be used for synchronization of the descrambler at the receiving end. The PSDU corresponds to the MAC PDU defined in the MAC layer and may include data generated / used in the upper layer. The PPDU tail bit may be used to return the encoder to the 0 state. The padding bits may be used to adjust the length of the data field in predetermined units.

[0096] MAC PDU is 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 can be composed of MAC PDUs and transmitted / received through PSDU of the data portion of the PPDU format.

[0097] The MAC header includes a frame control field, a duration / ID field, an address field, and other fields. The frame control field may include control information required for frame transmission / reception. The duration / ID field may be set to the time for transmitting the corresponding frame, etc. For details on the sequence control, QoS control, and HT control subfields of the MAC header, refer to the IEEE 802.11 standard.

[0098] The Null Data PPDU (NDP) format refers to a PPDU format that does not include a data field. In other words, the NDP refers to a frame format that includes the PPDU preamble of the general PPDU format (i.e., the L-STF, L-LTF, L-SIG fields, and additional non-legacy SIG, non-legacy STF, and non-legacy LTF (if present)) and does not include the remaining portion (i.e., the data field).

[0099] Figure 7 is a diagram illustrating an example of a PPDU defined in the IEEE 802.11 standard to which the present disclosure can be applied.

[0100] In standards such as IEEE 802.11a / g / n / ac / ax, various types of PPDUs have been used. The basic PPDU format (IEEE 802.11a / g) includes L-LTF, L-STF, L-SIG, and data fields. The basic PPDU format may also be referred to as a non-HT PPDU format (e.g., Figure 7 (as shown in (a)).

[0101] Compared to the basic PPDU format, the HT PPDU format (IEEE 802.11n) additionally includes HT-SIG, HT-STF, and HT-LFT fields. Figure 7The HT PPDU format shown in (b) may be referred to as an HT mixed format. Furthermore, an HT greenfield format PPDU may be defined, and this corresponds to a format consisting of an HT-GF-STF, HT-LTF1, HT-SIG, one or more HT-LTFs, and a data field, excluding L-STF, L-LTF, and L-SIG (not shown).

[0102] Compared to the basic PPDU format, an example of the VHT PPDU format (IEEE 802.11ac) additionally includes VHTSIG-A, VHT-STF, VHT-LTF, and VHT-SIG-B fields (e.g., Figure 7 (as shown in (c)).

[0103] Compared to the basic PPDU format, an example of the HE PPDU format (IEEE 802.11ax) additionally includes a repeated L-SIG (RL-SIG), HE-SIG-A, HE-SIG-B, HE-STF, HE-LTF, a packet extension (PE) field (such as Figure 7 (d) of FIG). Some fields may be excluded or their lengths may vary according to the detailed example of the HE PPDU format. For example, the HE-SIG-B field is included in the HE PPDU format for multi-user (MU), and the HE-SIG-B is not included in the HE PPDU format for single user (SU). 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 up to 8 μs. The extended range (HE ER) SU PPDU format does not include the HE-SIG-B field, and the length of the HE-SIG-A field may vary up to 16 μs. For example, the RL-SIG may be configured to be the same as the L-SIG. Based on the presence of the RL-SIG, the receiving STA may know whether the received PPDU is an HE PPDU or an EHT PPDU, which will be described later.

[0104] The EHT PPDU format may include Figure 7 (e) EHT MU (multi-user) and Figure 7 The EHT TB (trigger-based) PPDU in (f) of FIG. The EHT PPDU format is similar to the HE PPDU format in that it includes the RL-SIG following the L-SIG, but may include the U (Universal)-SIG, EHT-SIG, EHT-STF, and EHT-LTF following the RL-SIG.

[0105] Figure 7The EHT MU PPDU in (e) corresponds to a PPDU that carries one or more data (or PSDU) 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.

[0106] Compared with EHT MU PPDU, Figure 7 The EHT TB PPDU in (f) omits the EHT-SIG. A STA that receives a trigger for UL MU transmission (eg, a trigger frame or a triggered response schedule (TRS)) may perform UL transmission based on the EHT TB PPDU format.

[0107] The L-STF, L-LTF, L-SIG, RL-SIG, U-SIG (Universal Signal), and EHT-SIG fields may be coded and modulated so that even legacy STAs can attempt demodulation and decoding, and may be mapped based on a determined subcarrier frequency spacing (e.g., 312.5 kHz). These may be referred to as pre-EHT modulation fields. Subsequently, the EHT-STF, EHT-LTF, data, and PE fields may be coded and modulated so that STAs that successfully decode non-legacy SIGs (e.g., U-SIG and / or EHT-SIG) and obtain the information included in these fields may be demodulated and decoded, and may be mapped based on a determined subcarrier frequency spacing (e.g., 78.125 kHz). These may be referred to as EHT modulation fields.

[0108] 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. Furthermore, in the VHT PPDU format, the L-STF, L-LTF, L-SIG, and VHT-SIG-A fields may be referred to as non-VHT modulation fields, and the VHT STF, VHT-LTF, VHT-SIG-B, and data fields may be referred to as VHT modulation fields.

[0109] Included in Figure 7The U-SIG in the EHT PPDU format may be configured based on, for example, two symbols (e.g., two consecutive OFDM symbols). Each symbol used for the U-SIG (e.g., OFDM symbol) may have a duration of 4 μs, and the U-SIG may have a total duration of 8 μs. Each symbol of the U-SIG may be used to transmit 26 bits of information. For example, each symbol of the U-SIG may be transmitted and received based on 52 data tones and 4 pilot tones.

[0110] The U-SIG can be constructed in 20MHz units. For example, if an 80MHz PPDU is constructed, the U-SIG can be duplicated. That is, the same four U-SIGs can be included in the 80MHz PPDU. PPDUs with bandwidth exceeding 80MHz can include different U-SIGs.

[0111] For example, A uncoded bits may be transmitted via the U-SIG, the first symbol of the U-SIG (e.g., the U-SIG-1 symbol) may transmit the first X bits of information out of a total of A bits of information, and the second symbol of the U-SIG (e.g., the U-SIG-2 symbol) may transmit the remaining Y bits of information out of a total of A bits of information. The A bits of information (e.g., 52 uncoded bits) may include a CRC field (e.g., a 4-bit long field) and a tail field (e.g., a 6-bit long field). For example, the tail field may be used to terminate the trellis structure of the convolutional decoder and may be set to 0.

[0112] The bit information sent through U-SIG can be divided into version-independent bits and version-dependent bits. For example, U-SIG can be included in Figure 7 The U-SIG field format included in the EHT PPDU format and the U-SIG field included in the UHR PPDU format may be included in a new PPDU format (e.g., UHR PPDU format) not shown in the figure. The version-independent bits may be the same, and some or all of the version-dependent bits may be different.

[0113] For example, the size of the version-independent bit of the U-SIG can be fixed or variable. The version-independent bit can be assigned only to the U-SIG-1 symbol, or to both the U-SIG-1 symbol and the U-SIG-2 symbol. The version-independent bit and the version-dependent bit can be referred to by various names, such as the first control bit and the second control bit.

[0114] For example, the version-independent bits of the U-SIG may include a 3-bit physical layer version identifier (PHY version identifier), and this information may indicate the PHY version of the transmitted / received PPDU (e.g., EHT, UHR, etc.). 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 is related to UL communication, and the second value of the UL / DL flag field is related to DL communication. The version-independent bits of the U-SIG may include information about the length of a transmit opportunity (TXOP) and information about a BSS color ID.

[0115] For example, the version-related bits of the U-SIG may include information directly or indirectly indicating the type of the PPDU (eg, SU PPDU, MU PPDU, TB PPDU, etc.).

[0116] Information required for PPDU transmission and reception may be included in the U-SIG. For example, the U-SIG may also include information about bandwidth, information about the MCS technology applied to the non-legacy SIG (e.g., EHT-SIG or UHR-SIG, etc.), information indicating whether the DCM (Dual Carrier Modulation) technology (e.g., a technology for achieving 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, and information about whether the non-legacy SIG is generated across the entire frequency band.

[0117] Some of the information required for PPDU transmission and reception may be included in the U-SIG and / or the non-legacy SIG (e.g., EHT-SIG or UHR-SIG, etc.). For example, information on the type of non-legacy LTF / STF (e.g., EHT-LTF / EHT-STF or UHR-LTF / UHR-STF, etc.), information on the length of the non-legacy LTF and the CP (Cyclic Prefix) length, information on the GI (Guard Interval) applicable to the non-legacy LTF, information on preamble puncturing applicable to the PPDU, information on resource unit (RU) allocation, etc. may be included only in the U-SIG, only in the non-legacy SIG, or may be indicated by a combination of information included in the U-SIG and information included in the non-legacy SIG.

[0118] Preamble puncturing may indicate transmission of a PPDU in which no signal exists in one or more frequency bins within the PPDU's bandwidth. For example, the size of a frequency bin (or the resolution of preamble puncturing) may be defined as 20 MHz, 40 MHz, etc. For example, preamble puncturing may be applied to a PPDU bandwidth of a predetermined size or greater.

[0119] exist Figure 7In the example of [ ], non-legacy SIGs such as HE-SIG-B and EHT-SIG may include control information for receiving STAs. A non-legacy SIG may be transmitted over at least one symbol, and one symbol may be 4 μs long. 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.).

[0120] Non-legacy SIGs such as HE-SIG-B and EHT-SIG may include common fields and user-specific fields. The common fields and user-specific fields may be encoded separately.

[0121] In some cases, the common field can be omitted. For example, in compressed mode without OFDMA (Orthogonal Frequency Division Multiple Access), the common field can be omitted, and multiple STAs can receive the PPDU (e.g., the data field of the PPDU) on the same frequency band. In non-compressed mode with OFDMA, multiple users can receive the PPDU (e.g., the data field of the PPDU) on different frequency bands.

[0122] The number of user-specific fields may be determined based on the number of users. A user block field may include up to two user fields. Each user field may be associated with a MU-MIMO allocation or may be associated with a non-MU-MIMO allocation.

[0123] The common field may include a CRC bit and a tail bit, and the length of the CRC bit may be determined to be 4 bits, while the length of the tail bit may be determined to be 6 bits and set to 000000. The common field may include RU allocation information. The RU allocation information may include information about the positions of the RUs to which multiple users (i.e., multiple receiving STAs) are assigned.

[0124] A RU can include multiple subcarriers (or tones). RUs can be used when transmitting signals to multiple STAs based on OFDMA technology. In addition, RUs can be defined even when transmitting signals to a single STA. Resources can be allocated for non-legacy STFs, non-legacy LTFs, and data fields in units of RUs.

[0125] The applicable RU size can be defined based on the PPDU bandwidth. The RU can be defined identically or differently for the applied PPDU format (e.g., HEPPDU, EHT PPDU, UHR PPDU, etc.). For example, in the case of an 80MHz PPDU, the RU layout of the HEPPDU and EHT PPDU can be different. The applicable RU size, the number of RUs and RU positions, the DC (direct current) subcarrier position and number, the null subcarrier position and number, the guard subcarrier position and number, etc. for each PPDU bandwidth can be referred to as a tone plan. For example, a tone plan for high bandwidth can be defined in the form of multiple iterations of a low bandwidth tone plan.

[0126] RUs of various sizes can be defined as 26-tone RUs, 52-tone RUs, 106-tone RUs, 242-tone RUs, 484-tone RUs, 996-tone RUs, 2×996-tone RUs, 3×996-tone RUs, and the like. An MRU (Multi-RU) is distinct from multiple individual RUs and corresponds to a group of subcarriers consisting of multiple RUs. For example, an MRU can be defined as 52+26 tones, 106+26 tones, 484+242 tones, 996+484 tones, 996+484+242 tones, 2×996+484 tones, 3×996 tones, or 3×996+484 tones. In addition, the multiple RUs that make up an MRU may or may not be contiguous in the frequency domain.

[0127] The specific size of an RU can be reduced or expanded. Therefore, the specific size of each RU (i.e., the number of corresponding tones) in this disclosure is not restrictive but illustrative. In addition, in this disclosure, within a predetermined bandwidth (e.g., 20 MHz, 40 MHz, 80 MHz, 160 MHz, 320 MHz, etc.), the number of RUs can vary depending on the RU size.

[0128] Figure 7 The names of each field in the PPDU format are exemplary, and the scope of the present disclosure is not limited by these names. In addition, the examples of the present disclosure can be applied to Figure 7 The PPDU format shown in Figure 7 A new PPDU format that excludes some fields and / or adds some fields to the existing PPDU format.

[0129] Figure 8 is a diagram illustrating an exemplary format of a trigger frame to which the present disclosure can be applied.

[0130] The trigger frame can allocate resources for one or more TB PPDU transmissions and can solicit TB PPDU transmissions. The trigger frame can also include other information required by the STA that sends the TB PPDU in response. The trigger frame can include a common information field and a user information list field in the frame body.

[0131] The common information field may include information common to one or more TB PPDU transmissions requested by the trigger frame, such as trigger type, UL length, presence of subsequent trigger frames (e.g., more TFs), presence of required channel sensing (CS), UL BW (bandwidth), etc. Figure 8 The EHT variable public information field format is exemplarily shown.

[0132] The 4-bit Trigger Type subfield can have a value of 0 to 15. Among them, the values 0, 1, 2, 3, 4, 5, 6 and 7 of the Trigger Type subfield are defined to correspond to Basic, Beamforming Report Poll (BFRP), Multi-User Block Acknowledgement Request (MU-BAR), Multi-User Request to Send (MU-RTS), Buffer Status Report Poll (BSRP), Multicast with Retry (GCR) MU-BAR, Bandwidth Query Report Poll (BQRP) and NDP Feedback Report Poll (NFRP), respectively, and values 8 to 15 are defined as reserved.

[0133] Among the common information, the trigger-related common information subfield may include information selectively included based on the trigger type.

[0134] The trigger frame may include a specific user information field, which does not contain user-specific information but rather contains extended common information not provided in the common information field.

[0135] A user information list contains zero or more user information fields. Figure 8 The EHT variable user information field format is exemplarily illustrated.

[0136] The AID12 subfield essentially indicates that it is a user information field for the STA with the corresponding AID. Furthermore, if the AID12 field has a predetermined specific value, it can be used for other purposes, such as allocating a random access (RA)-RU, or configured as a specific user information field. A specific user information field is a user information field that does not include user-specific information but instead includes extended public information not provided in the public information field. For example, the specific user information field can be identified by an AID12 value of 2007, and the specific user information field flag subfield in the public information field can indicate whether the specific user information field is included.

[0137] The RU allocation subfield may indicate the size and location of the RU / MRU. To this end, the RU allocation subfield may be interpreted together with the PS160 (primary / secondary 160 MHz) subfield of the user information field, the UL BW subfield of the common information field, and the like.

[0138] Triggered shared transmission opportunity (TXOP) relay execution process

[0139] The triggered TXOP sharing procedure may allow an AP to allocate a portion of its TXOP to an associated non-AP STA for transmitting one or more non-TB PPDUs.

[0140] A TXOP may correspond to a duration during which a specific QoS STA (e.g., an AP STA and / or a non-AP STA) is authorized to initiate a frame exchange sequence on a wireless medium (WM). For example, a TXOP may be defined by a start time and a maximum duration.

[0141] When a TXOP sharing mode subfield related to a triggered TXOP sharing mode is defined in a MU-RTS frame and a value of the subfield is not 0, the frame may be referred to as a MU-RTS TXOP sharing (TXS) trigger frame.

[0142] For example, the TXOP Sharing Mode subfield may be encoded as follows.

[0143] If a value of the TXOP Sharing Mode subfield of the MU-RTS frame is 0, it corresponds to a MU-RTS that does not initiate the MU-RTS TXOP sharing procedure.

[0144] If the value of the TXOP Sharing Mode subfield of the MU-RTS frame is 1, it corresponds to a MU-RTS initiating the MU-RTS TXOP sharing procedure, where a scheduled STA may only transmit MPDUs addressed to its associated AP.

[0145] If the value of the TXOP Sharing Mode subfield of the MU-RTS frame is 2, it corresponds to a MU-RTS initiating the MU-RTS TXOP sharing procedure, which enables a scheduled STA to transmit an MPDU addressed to its associated AP or to another STA.

[0146] A value of 3 of the TXOP Sharing Mode subfield of the MU-RTS frame may be defined as a reserved value.

[0147] Specifically, according to triggered TXOP sharing mode 1, the AP may send a MU-RTS TXS trigger frame to allocate time for the STA to send a non-TB PPDU to the AP, and the STA may respond to the trigger frame.

[0148] According to triggered TXOP sharing mode 2, the AP can send a MU-RTS TXS trigger frame to allocate time for a STA to send a non-TB PPDU to other STAs or the AP, and the STA can respond to the trigger frame. In triggered TXOP sharing mode 2, the transmission of a STA to another STA can be called peer-to-peer (P2P) transmission.

[0149] A STA that uses information from a received MU-RTS TXS Trigger frame as the latest basis for updating its Network Allocation Vector (NAV) should not reset its NAV after the NAV Timeout timer expires unless it receives a CF-End frame that meets the TXOP truncation conditions.

[0150] NAV is maintained by each STA and is an indicator of the time period during which the STA does not initiate transmission on the wireless medium (WM), regardless of whether the clear channel assessment (CCA) function of the STA senses that the WM is busy. For example, the expected channel occupancy time can be indicated by duration information in frames (e.g., RTS / CTS frames) exchanged between the transmitting STA and the receiving STA, and the remaining STAs (e.g., third-party STAs) other than the transmitting STA and the receiving STA can set a NAV timer corresponding to the indicated time period and cannot perform transmission on the WM until the value of the NAV timer expires (or becomes 0).

[0151] After sending a CTS frame requested by a MU-RTS TXS Trigger frame received from the AP to which the STA is associated, the STA may ignore the NAV set by the AP within the time allotment signaled in the MU-RTS TXS Trigger frame. That is, if the NAV is set, the wireless medium is considered busy or no transmission is initiated. Therefore, to allow STAs that have been allocated / shared the AP's TXOP to transmit during the triggered TXOP sharing process, the STA may ignore the NAV set by the AP.

[0152] Figure 9 is a diagram for explaining an example of a triggered TXOP sharing procedure to which the present disclosure can be applied.

[0153] Figure 9 The example corresponds to an example of triggered TXOP sharing mode 2. That is, it is assumed that the value of the TXOP Sharing Mode subfield of the MU-RTS TXS trigger frame transmitted by the AP to the non-AP STA1 is set to 2.

[0154] Here, the MU-RTS TXS trigger frame sent by the AP to the non-AP STA1 may include time allocation information.

[0155] For example, the user information field format of the MU-RTS TXS trigger frame may include an AID12 subfield, an RU allocation subfield, an allocation duration subfield, a PS160 subfield, and a reserved bit.

[0156] Here, the AID12 subfield corresponds to the identification information of the STA, and the Allocation Duration subfield may indicate the duration allocated to the corresponding STA. In this case, the corresponding duration may be indicated in units of 16 microseconds. In this regard, for STA1 (i.e., a non-AP STA), the corresponding duration may be applied from the time the physical layer indication primitive (e.g., PHY-RXEND.Indication primitive) of the PPDU including the MU-RTS TXS Trigger frame is generated.

[0157] STA1 can send a CTS frame in response to the MU-RTS TXS trigger frame from the AP and send data to STA2 (i.e., P2P transmission) during the time allocated by the MU-RTS TXS trigger frame (which corresponds to a portion of the AP's TXOP) and receive a block ACK. When the time allocated by the MU-RTS TXS trigger frame expires (e.g., after PIFS from the expiration of the allocated time), the AP can perform transmission during its TXOP (e.g., send data to another STA, i.e., STA3). Although Figure 9 Not shown in FIG, STA1 may also send frames to the AP during the time when the MU-RTS TXS trigger frame is allocated.

[0158] When the distance between the AP and the STA is long, frame transmission and reception may not be performed correctly due to low signal-to-noise ratio (SNR) and / or throughput caused by high propagation loss.

[0159] In order to solve these problems, various methods may be used, such as changing the PPDU format to support a long distance, and in particular, a method of using a relay STA when performing frame transmission and reception between STAs may be considered.

[0160] For example, when the AP needs to send a DL frame to a target STA located far away, the AP may first send the frame to another STA located at an appropriate distance, and the STA receiving the frame may be configured to resend the frame to the target STA.

[0161] In the present disclosure, various embodiments propose specific protocols / signaling methods for relay transmission as described above. In particular, in the present disclosure, various embodiments propose methods for configuring and indicating an ACK policy that enables fast relay transmission.

[0162] In this regard, when the AP transmits a frame to the target STA, since STA-to-STA frame transmission is required when using a relay STA, the triggered TXOP sharing method described above in this disclosure can be utilized. Specifically, this disclosure proposes a relay transmission method utilizing triggered TXOP sharing and a method for configuring / indicating an ACK policy related thereto.

[0163] In conjunction with the description in this disclosure, a STA that performs relay is referred to as a relay STA, and the STA may include an AP STA or a non-AP STA.

[0164] Implementation Method 1

[0165] This embodiment relates to a method for performing relay transmission based on a triggered TXOP sharing mode and a related method for configuring / indicating an ACK policy.

[0166] Figure 10 An example of a relay transmission process according to an embodiment of the present disclosure is illustrated.

[0167] Reference Figure 10 When using the MU-RTS TXS trigger frame (TF) to perform relay transmission, the AP needs to send the MU-RTS TXS trigger frame and data frames.

[0168] exist Figure 10 , STA 1 corresponds to the relay STA, and STA 2 corresponds to the target STA to which the AP will eventually send the frame.

[0169] For example, the AP may allocate a time (eg, a specific time period) when STA 1 may transmit to STA 2 via a MU-RTS TXS trigger frame (step S1010 ).

[0170] In this regard, a new mode may be indicated via the Triggered TXOP Sharing Mode subfield in the MU-RTS TXS Trigger frame. Specifically, a previously reserved value in this subfield (e.g., value 3) may be newly defined to indicate the mode for initiating the MU-RTS TXOP sharing process for relay transmission.

[0171] Additionally or alternatively, more bits may be needed to indicate a combination of modes. In this case, reserved bits in the Common Information field of the MU-RTS TXS Trigger frame may be additionally utilized. For example, the following modes may be additionally defined / indicated: a mode that allows MPDUs to be sent to the AP as well (corresponding to a value of 1 in the TXOP Sharing Mode subfield triggered together with the corresponding relay transmission), a mode that allows P2P transmission (corresponding to a value of 2 in the TXOP Sharing Mode subfield triggered together with the corresponding relay transmission), and / or a mode that allows all modes together with the corresponding relay transmission. Here, one or more of the above additional modes may be present.

[0172] If the relay STA, ie, STA1, successfully (ie, properly and correctly) receives the MU-RTS TXS trigger frame transmitted by the AP, STA1 may respond to the AP via a CTS frame (step S1020).

[0173] The AP receiving the CTS frame may transmit a frame (eg, a QoS data frame) to be transmitted to STA 2 to STA 1 corresponding to the relay STA (step S1030). At this time, the frame may be transmitted and received in an A-MPDU format consisting of one or more MPDUs.

[0174] In this regard, the field settings in the MAC header of the corresponding frame can be as follows. Specifically, the ACK policy related fields in the To DS field (To DS) and From DS (From DS) field, multiple address fields, and the QoS control field can be set according to the method described below.

[0175] Here, the To DS field and From DS field included in the Frame Control field in the MAC header may be included in the Frame Control field of the MAC header. For example, if both the To DS field and From DS field are set to 0 (i.e., [0, 0]), this may relate to transmission and reception between STAs within an IBSS or a single BSS, if both the To DS field and From DS field are set to [0, 1], this may relate to data frames transmitted from an AP to a wireless STA (i.e., DL transmission and reception), if both the To DS field and From DS field are set to [1, 0], this may relate to data frames transmitted from a wireless STA to an AP (i.e., UL transmission and reception), and if both the To DS field and From DS field are set to [1, 1], this may relate to transmission and reception via a wireless bridge (e.g., mesh-based transmission).

[0176] First, regarding the relay transmission operation proposed in the present disclosure, a method of setting values of a To DS field, a From DS field, and a plurality of address fields is described.

[0177] For example, the To DS field may be set to a value of 0, and the From DS field may be set to a value of 1.

[0178] At this time, the first address field (e.g., AD1 field) can be set to the MAC address of STA 1 (i.e., relay STA) as the receiver address (RA), and the second address field (e.g., AD2 field) can be set to the MAC address of the AP (e.g., BSSID, etc.) as the transmitter address (TA).

[0179] In this regard, if only the fourth address field (e.g., AD4 field) is set, the source address (SA) of the third address field (e.g., AD3 field) is set as described above, and the MAC address of STA 2 (i.e., the target STA) may be set in the fourth address field. Here, the source address (SA) may correspond to the MAC address (e.g., BSSID) of the AP. Additionally or alternatively, if the third address field and the fourth address field are set, the third address field may be set to the MAC address (e.g., BSSID) of the AP as the source address (SA), and the fourth address field may be set to the MAC address (e.g., BSSID) of STA2 as the destination address (DA). Conversely, the third address field may be set to the MAC address of STA 2 as the destination address (DA), and the fourth address field may be set to the MAC address (e.g., BSSID) of the AP as the source address (SA).

[0180] For another example, the To DS field may be set to a value of 1 and the From DS field may be set to a value of 1.

[0181] At this time, the first address field (e.g., AD1 field) can be set to the MAC address of STA 1 (i.e., relay STA) as the receiver address (RA), the second address field (e.g., AD2 field) can be set to the MAC address (e.g., BSSID, etc.) of the AP as the transmitter address (TA), the third address field (e.g., AD3 field) can be set to the MAC address of STA2 as the destination address (DA), and the fourth address field (e.g., AD4 field) can be set to the MAC address (e.g., BSSID) of the AP as the source address (SA).

[0182] Next, regarding the relay transmission operation proposed in the present disclosure, the setting of the ACK policy related field in the QoS control field is described.

[0183] Basically, the ACK policy described below may be an ACK policy for STA1, ie, the relay STA. At this time, it is possible to consider a case where STA1 only checks (eg, decodes) the MAC header of the MPDU.

[0184] That is, STA1 can notify the AP through ACK information (e.g., general ACK) that it has checked the MAC header of at least one MPDU, rather than responding with a block ACK by checking the frame check sequence (FCS) of the frame body. Here, the at least one MPDU can be included in the A-MPDU sent by the AP to STA1.

[0185] As previously mentioned, the ACK policy proposed in this disclosure for sending an ACK (i.e., ACK information) for an A-MPDU transmitted by a STA is not defined in existing wireless LAN systems. Therefore, it is necessary to newly define such an ACK policy, and to this end, the following methods (hereinafter referred to as Method 1 and Method 2) can be considered.

[0186] (Method 1)

[0187] The ACK policy related field (e.g., ACK policy indicator field) included in the MAC header consists of 2 bits. Therefore, a method can be considered in which the ACK policy is interpreted differently by indicating the ACK policy using existing / defined values (e.g., 01, 00) according to the field settings of the To DS field, From DS field, and multiple address fields.

[0188] That is, by considering the value of the ACK policy related field together with the values of other fields in the MAC header (e.g., To DS field, From DS field, Address field, etc.), STA 1 can be configured / defined to interpret the ACK policy indicated by the AP in a different manner from the existing situation.

[0189] Therefore, there are field settings for the To DS field and From DS field and multiple address fields as described above, and when the ACK policy-related field is set to a specific value, the indicated ACK policy can be interpreted as meaning that the MAC header of at least one MPDU has been verified for the received A-MPDU.

[0190] (Method 2)

[0191] One approach that can be considered is to set the ACK policy-related field to a value indicating an implicit block acknowledgement request (implicitBAR) (e.g., 00) and use the A-Control field to indicate the ACK policy as described above. For example, to indicate the ACK policy, a specific subfield of a new control ID using the A-Control field (e.g., a 2-bit relay transmission information (RXTI) control subfield) can be defined (e.g., a 2-bit relay transmission information (RXTI) control subfield).

[0192] That is, the ACK Policy Related field indicates an implicit BAR, and by using the A-Control field described later, an indication with the same meaning is performed for the corresponding A-MPDU, that is, an ACK is sent when the MAC header of at least one MPDU is verified for the received A-MPDU. In this regard, a 1-bit field can be used to indicate this meaning.

[0193] Additionally or alternatively, in addition to the above-mentioned ACK policy information, the AP may inform STA 1 of one or more additional ACK policy information as follows.

[0194] - When the relay STA 1 sends to the target STA 2, STA 2 will send ACK information related to the ACK policy of STA 1

[0195] -After the relay STA 1 receives the ACK information from the target STA 2, STA 1 will send the ACK information related to the AP

[0196] First, a method for notifying STA 2 of an ACK policy related to ACK information to be delivered to STA 1 will be described.

[0197] For example, some fields that are not necessarily required in the MAC header can be used to indicate the corresponding ACK policy. As a specific example, two bits of bits 8 to 15 of the QoS control field in the MAC header can be used to indicate the existing ACK policy (for example, 2 bits of information). In particular, if an ACK policy that can only be used in relay transmission can be selected, only 1 bit can be used. As an example, the 1 bit can be set to indicate an implicit BAR or block ACK. In this way, STA 1 that is identified as a relay transmission through the triggered TXOP sharing (TXS) mode subfield, address field, etc. can interpret the corresponding bits 8 to 15 differently from the existing situation. In this case, in terms of implementation, it may be necessary to change the MAC header processing method of the existing STA.

[0198] For another example, a subfield (e.g., a 2-bit RXTI control subfield) can be defined using a new control ID in the A-Control field as described above. Similarly, this subfield can use 2 bits (e.g., 2 bits of information) to indicate the ACK policy. In particular, if an ACK policy that can only be used in relay transmissions can be selected, only 1 bit can be used. As an example, this 1 bit can be set to indicate an implicit BAR or block ACK.

[0199] Next, a method for notifying STA 1 of an ACK policy related to ACK information to be sent to the AP is described.

[0200] For example, some fields that are not necessarily required in the MAC header can be used to indicate the corresponding ACK policy. As a specific example, two bits of bits 8 to 15 of the QoS control field in the MAC header can be used to indicate the existing ACK policy (e.g., 2 bits of information). In particular, if an ACK policy that can only be used in relay transmission can be selected, only 1 bit can be used. As an example, the 1 bit can be set to indicate an implicit BAR or a block ACK. Here, the implicit BAR can mean that the relay STA, i.e., STA1, sends a block ACK (BA) to the AP after SIFS after receiving the block ACK (BA) from STA 2. In this way, STA 1, which is identified as a relay transmission through the triggered TXOP sharing (TXS) mode subfield, the address field, etc., can interpret bits 8 to 15 differently from the existing situation. In this case, in terms of implementation, it may be necessary to change the MAC header processing method of the existing STA.

[0201] For another example, a subfield (e.g., a 2-bit RXTI control subfield) can be defined using a new control ID of the A-Control field as described above. Similarly, this subfield can use 2 bits (e.g., 2 bits of information) to indicate the ACK policy. In particular, if an ACK policy that can only be used in relay transmissions can be selected, only 1 bit can be used. As an example, this 1 bit can be set to indicate an implicit BAR or a block ACK. Here, the implicit BAR can mean that the relay STA, i.e., STA 1, sends a block ACK (BA) to the AP after a SIFS after receiving a block ACK (BA) from STA 2.

[0202] STA 1, which has received the A-MPDU including the QoS data frame from the AP, may send ACK to the AP if it has checked (eg, decoded) at least one MAC header (step S1040).

[0203] Through this step, the AP can recognize that STA 1 can send at least one frame to be sent to STA 2. From the perspective of reducing protocol overhead, this step can be omitted.

[0204] STA 1, which has sent ACK to the AP, can send the data frame (e.g., QoS data frame) successfully received from the AP to STA 2 corresponding to the target STA (step S1050). At this time, the frame can be sent and received in the form of an A-MPDU composed of one or more MPDUs.

[0205] In this regard, the field settings in the MAC header of the corresponding frame (MAC header field settings) may be as follows.

[0206] For example, the To DS field may be set to a value of 0, and the From DS field may be set to a value of 0. Alternatively, the setting of the To DS field and the From DS field as in step S1030 described above may be applied.

[0207] At this time, regarding the multiple address fields, the first address field (e.g., AD1 field) can be set to the MAC address of STA 2 (i.e., the destination STA) as the receiver address (RA), and the second address field (e.g., AD2 field) can be set to the MAC address of STA 1 as the transmitter address (TA). In this regard, the source address (SA) can be set to the MAC address of the AP (e.g., BSSID), and the destination address (DA) can be set to the address of STA 2. At this time, the source address (SA) and the destination address (DA) can be set to the third address field (e.g., AD3 field) and the fourth address field (e.g., AD4 field), respectively, and the opposite situation is also possible.

[0208] Regarding the ACK policy setting in the QoS Control field, the corresponding ACK policy can basically be the ACK policy for STA 2, the target STA. Therefore, it can be set to the ACK policy indicated by the AP when sending to STA 1, or it can always be set to the implicit BAR.

[0209] STA 2 may send a block ACK frame to STA 1 according to the above ACK policy (step S1060 ).

[0210] Finally, STA 1, which has received the Block ACK frame from STA 2, may transmit a Block ACK frame including the Block ACK information received from STA 2 to the AP (step S1070).

[0211] Implementation Method 2

[0212] This embodiment is directed to a method for reducing signaling overhead in the relay process according to the above-mentioned embodiment 1.

[0213] Figure 11 Another example of the relay transmission process according to an embodiment of the present disclosure is illustrated.

[0214] Reference Figure 11 In the case of the relay process of Example 1, since multiple frames need to be exchanged, a method for reducing overhead is required. In this regard, a method of sending multiple frames in a cascaded form in an A-MPDU can be applied.

[0215] exist Figure 11, STA 1 corresponds to the relay STA, and STA 2 corresponds to the target STA to which the AP will eventually send the frame.

[0216] For example, the AP may include a MU-RTS TXS trigger frame that allocates a time (e.g., a specific time period) at which STA1 can transmit to STA2 and a frame to be transmitted to STA2 (e.g., a QoS data frame) in the A-MPDU, and transmit the MU-RTS TXS trigger frame and the frame to be transmitted to STA2 to STA1 (step S1110).

[0217] In this regard, for mode settings related to the MU-RTS TXS trigger frame (i.e., triggered TXOP sharing mode), the method described in step S1010 of Embodiment 1 can be applied. Additionally, for setting the MAC header field of the frame to be transmitted to STA 2, the method described in step S1030 of Embodiment 1 can be applied.

[0218] When the relay STA (ie, STA 1) successfully receives the MU-RTS TXS trigger frame sent by the AP and the frame to be sent to STA 2, it may respond to the AP by including a CTS frame and an ACK frame in the A-MPDU (step S1120).

[0219] In this regard, as in the ACK policy description of step S1030 of embodiment 1, the corresponding ACK frame may inform STA 2 that it has acknowledged the MAC header of at least one MPDU corresponding to the frame to be transmitted.

[0220] STA 1 may transmit the frame (eg, QoS data frame) successfully received from the AP to STA 2 corresponding to the target STA (step S1130). At this time, the frame may be transmitted and received in the form of an A-MPDU consisting of one or more MPDUs.

[0221] STA 2 may send a block ACK frame to STA 1 according to the ACK policy (step S1140 ).

[0222] Finally, STA 1, which has received the Block ACK frame from STA 2, may transmit a Block ACK frame including the Block ACK information received from STA 2 to the AP (step S1150).

[0223] Below, we will refer to Figure 12 and Figure 13 The operation of the STA according to the embodiment of the present disclosure described above is described.

[0224] Right now, Figure 12 and Figure 13 The examples of may correspond to some of the various examples of the present disclosure. For example, in Figure 12 and Figure 13 In the example, the first STA may correspond to the relay STA, and the second STA may correspond to the target STA (ie, the final STA) of the relay transmission.

[0225] Figure 12 A flowchart illustrating operations performed by a first STA according to an embodiment of the present disclosure is illustrated.

[0226] The first STA may receive a first A-MPDU including data to be transmitted to the second STA from an access point (AP) ( S1210 ).

[0227] The first STA may transmit an ACK frame for the first A-MPDU to the AP ( S1220 ).

[0228] In this regard, the ACK frame may include ACK information indicating whether at least one MAC header included in the first A-MPDU is checked. For example, if at least one MAC header is checked, the first STA may send an ACK to the AP.

[0229] At this time, the ACK information may be based on the ACK policy indicated by an ACK policy-related field (eg, ACK policy indicator field) and at least one other field included in the MAC header of the first A-MPDU.

[0230] For example, the at least one other field may include a To DS field, a From DS field, and a plurality of address fields included in the MAC header.

[0231] In this regard, when the To DS field is set to a value of 0 and the From DS field is set to a value of 1, the plurality of address fields may include one or more of a first address field (e.g., an AD1 field), a second address field (e.g., an AD2 field), a third address field (e.g., an AD3 field), or a fourth address field (e.g., an AD4 field). For example, three address fields or four address fields may be set / included in one MAC header. Here, the first address field may be set to identification information of the first STA as a receiver address (RA), the second address field may be set to identification information of the AP as a transmitter address (TA), the third address field may be set to identification information of the second STA as a destination address (DA), and the fourth address field may be set to identification information of the AP as a source address (SA).

[0232] Additionally or alternatively, when the To DS field is set to a value of 1 and the From DS field is set to a value of 1, the plurality of address fields may include a first address field (e.g., an AD1 field), a second address field (e.g., an AD2 field), a third address field (e.g., an AD3 field), and a fourth address field (e.g., an AD4 field). Here, the first address field may be set to identification information of the first STA as a receiver address (RA), the second address field may be set to identification information of the AP as a transmitter address (TA), the third address field may be set to identification information of the second STA as a destination address (DA), and the fourth address field may be set to identification information of the AP as a source address (SA).

[0233] For another example, at least one other field may include specific information based on the aggregation control (A-Control) field included in the first A-MPDU, wherein the specific information may correspond to relay transmission-related control information configured using a specific control identifier (control ID) of the aggregation control field.

[0234] Subsequently, the first STA may transmit a second A-MPDU including the data in step S1210 to the second STA ( S1230 ).

[0235] In this regard, the first A-MPDU in step S1210 may include at least one of first information indicating an ACK policy associated with ACK information transmitted for the second A-MPDU, and second information indicating an ACK policy associated with ACK information received for the ACK frame transmitted for the second A-MPDU. Here, the first information may be associated with an ACK policy for ACK transmission from the second STA to the first STA, and the second information may be associated with an ACK policy for ACK transmission from the first STA to the AP after the first STA receives ACK information from the second STA.

[0236] For example, the first information and the second information may each consist of 1 bit or 2 bits of information in bits 8 to 15 of the QoS control field included in the first A-MPDU, or may consist of a relay-related subfield based on a specific control identifier of the aggregation control (A-control) field included in the first A-MPDU. That is, the first information may consist of 1 bit or 2 bits, and the second information may consist of 1 bit or 2 bits.

[0237] For example, if the first information consists of one bit, the ACK policy indicated by the first information may correspond to either an implicit block acknowledgement request (implicit BAR) or a block ACK. Additionally or alternatively, if the second information consists of one bit, the ACK policy indicated by the second information may correspond to either an implicit BAR or a block ACK. Here, the implicit BAR may correspond to STA 1, as a relay STA, transmitting a block ACK (BA) to the AP after a SIFS after receiving a block ACK (BA) from STA 2.

[0238] In addition, before step S1210, the first STA may receive a trigger frame from the AP, the trigger frame including information indicating a mode for relay transmission within a triggered transmission opportunity (TXOP). In this case, the reception of the first A-MPDU and the transmission of the second A-MPDU described above may be performed within a time interval allocated based on the trigger frame. In addition, the first STA may send a CTS frame to the AP in response to receiving the trigger frame.

[0239] In addition, after step S1230, the first STA may receive a first response frame including block ACK information for the second A-MPDU from the second STA. The first STA may send a second response frame including the block ACK information received from the second STA to the AP.

[0240] Figure 12 The method described in the example of the first STA can be performed by Figure 1 The first device (100) performs. For example, Figure 1 One or more processors (102) of the first device (100) may be configured to receive, through one or more transceivers (106), a first A-MPDU including data transmitted from an AP to a second STA, send an ACK frame for the first A-MPDU to the AP, and send a second A-MPDU including corresponding data to the second STA.

[0241] For example, the one or more processors (102) of the first device (100) may be configured to decode the received first A-MPDU to determine an ACK policy for which ACK information is configured, and determine ACK information to be sent to the AP based on the ACK policy. Thereafter, the one or more processors (102) of the first device (100) may be configured to encode a second A-MPDU including the data included in the received first A-MPDU and send it to the second STA.

[0242] Additionally, the one or more memories (104) of the first device (100) may store instructions that, when executed by the one or more processors (102), are used to perform Figure 12 or the methods described in the examples above.

[0243] Figure 13 A flowchart illustrating operations performed by an AP according to an embodiment of the present disclosure is illustrated.

[0244] The AP may transmit an A-MPDU including data to be transmitted to the second STA to the first STA ( S1310 ) Thereafter, the AP may receive an ACK frame for the A-MPDU from the first STA.

[0245] In this regard, the ACK frame may include ACK information indicating whether to check at least one MAC header included in the A-MPDU. Here, the ACK information may be based on the ACK policy indicated by the ACK policy-related field (e.g., ACK policy indicator field) and at least one other field included in the A-MPDU.

[0246] Figure 13 The detailed description of the ACK information in the A-MPDU, the fields in the MAC header included in the A-MPDU, various field / bit configurations related to the ACK policy, additional procedures, etc. Figure 12 The examples are the same as those described in , so redundant description is omitted.

[0247] Figure 13 The method performed by the AP described in the example can be performed by Figure 1 The second device (200) is executed. For example, Figure 1 One or more processors (202) of the second device (200) may be configured to send an A-MPDU including data to be sent to the second STA to the first STA through one or more transceivers (206), and receive an ACK frame for the A-MPDU from the first STA.

[0248] For example, one or more processors (202) of the second device (200) may be configured to configure a MAC header by encoding an ACK policy related field and at least one other field when configuring the A-MPDU to indicate an ACK policy for the A-MPDU.

[0249] Additionally, the one or more memories (204) of the second device (200) may store instructions that, when executed by the one or more processors (202), are used to perform Figure 13 or the methods described in the examples above.

[0250] In existing wireless LAN systems, the signaling / protocols supporting relay transmission are not clearly defined. Consequently, signal transmission and reception to distant STAs often fail. To address this issue, the present disclosure proposes a signaling / protocol method for supporting relay transmission. Specifically, the method proposed in this disclosure defines a new ACK policy for fast ACK transmission related to relay transmission based on the A-MPDU structure, enabling relay transmission to be performed with improved reliability and speed.

[0251] The above-mentioned embodiments combine the elements and features of the present disclosure in a predetermined form. Unless otherwise explicitly mentioned, each element or feature should be considered as optional. Each element or feature can be implemented in a form not combined with other elements or features. In addition, the embodiments of the present disclosure may include some elements and / or features of the combination. The order of the operations described in the embodiments of the present disclosure may be changed. Some elements or features of an embodiment may be included in other embodiments, or may be replaced by corresponding elements or features of other embodiments. Obviously, an embodiment may include claims that do not have a clear reference relationship in the combined claims, or may be included as new claims through modification after application.

[0252] It is clear to those skilled in the relevant art that the present disclosure may be implemented in other specific forms within the scope of the essential features of the present disclosure. Therefore, the above detailed description should not be interpreted restrictively in every aspect, but should be considered as illustrative. The scope of the present disclosure should be determined by a reasonable interpretation of the appended claims, and all changes within the scope of equivalents of the present disclosure are included within the scope of the present disclosure.

[0253] The scope of the present disclosure includes software or machine executable commands (e.g., operating systems, applications, firmware, programs, etc.) that perform operations in accordance with the methods of various embodiments in a device or computer, and non-transitory computer-readable media that enable the software or commands, etc. to be stored and executable in a device or computer. Commands that can be used to program a processing system that performs the features described in this disclosure can be stored in a storage medium or a computer-readable storage medium, and the features described in this disclosure can be implemented by using a computer program product that includes such a storage medium. The storage medium may include high-speed random access memory, such as, but not limited to, DRAM, SRAM, DDR RAM, or other random access solid-state storage devices, and it may include non-volatile memory, such as, for example, 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 located away from the processor. The memory, or alternatively, the non-volatile memory device in the memory includes a non-transitory computer-readable storage medium. The features described in this disclosure may be stored in any machine-readable medium to control the hardware of a processing system and may be integrated into software and / or firmware that allows the processing system to utilize the results from the embodiments of this disclosure to interact with other mechanisms. Such software or firmware may include, but is not limited to, application code, device drivers, operating systems, and execution environments / containers.

[0254] Industrial Applicability

[0255] The method proposed in the present disclosure is mainly described based on an example of application to a system based on IEEE 802.11, but can be applied to various WLANs or wireless communication systems other than the system based on IEEE 802.11.

Claims

1. A method performed by a first station (STA) in a wireless LAN system, the method comprising: receiving, from an access point AP, a first aggregated MAC protocol data unit A-MPDU including data to be sent to a second STA; Sending an acknowledgment ACK frame for the first A-MPDU to the AP; as well as sending a second A-MPDU including the data to the second STA, wherein the ACK frame includes ACK information indicating whether to check at least one MAC header included in the first A-MPDU, and The ACK information is based on an ACK policy indicated by an ACK policy related field and at least one other field included in the first A-MPDU.

2. The method according to claim 1, wherein The at least one other field includes a To DS field, a From DS field, and a plurality of address fields included in the at least one MAC header.

3. The method according to claim 2, wherein: Based on the To DS field being set to a value of 0 and the From DS field being set to a value of 1, The plurality of address fields include at least one of a first address field, a second address field, a third address field, or a fourth address field, The first address field is set to a receiver address RA having identification information for the first STA, The second address field is set to a transmitter address TA having identification information for the AP, The third address field is set to a destination address DA having identification information for the second STA, and The fourth address field is set to a source address SA having identification information for the AP.

4. The method according to claim 2, wherein: Based on the To DS field being set to a value of 1 and the From DS field being set to a value of 1, The plurality of address fields include a first address field, a second address field, a third address field, and a fourth address field, The first address field is set to a receiving address RA having identification information for the first STA, The second address field is set to a transmission address TA having identification information for the AP, The third address field is set to a destination address DA having identification information for the second STA, and The fourth address field is set to a source address SA having identification information for the AP.

5. The method according to claim 1, wherein The at least one other field includes specific information based on an aggregation control A-Control field included in the first A-MPDU.

6. The method according to claim 5, wherein: The specific information corresponds to relay transmission related control information configured using a specific control identifier control ID of the aggregation control field.

7. The method according to claim 1, wherein The first A-MPDU includes at least one of first information indicating an ACK policy related to ACK information transmitted for the second A-MPDU or second information indicating an ACK policy related to ACK information received for an ACK frame transmitted for the second A-MPDU.

8. The method according to claim 7, wherein: Each of the first information and the second information consists of the following items: 1-bit information or 2-bit information in bits 8 to 15 of the Quality of Service (QoS) control field included in the first A-MPDU, or a relay-related subfield based on a specific control identifier of the aggregation control (A-control) field included in the first A-MPDU.

9. The method according to claim 7, wherein: The first information consists of 1 bit or 2 bits, and the second information consists of 1 bit or 2 bits. Based on the first information consisting of 1 bit, the ACK policy indicated by the first information corresponds to one of implicit block acknowledgement request implicit BAR or block ACK, and Based on the second information consisting of 1 bit, the ACK policy indicated by the second information corresponds to one of implicit BAR or block ACK.

10. The method according to claim 1, further comprising: receiving a trigger frame from the AP, the trigger frame including information indicating a mode for relay transmission within a triggered transmission opportunity TXOP, The receiving of the first A-MPDU and the sending of the second A-MPDU are performed within a duration allocated based on the trigger frame.

11. The method according to claim 1 , further comprising: receiving, from the second STA, a first response frame including block ACK information for the second A-MPDU; as well as A second response frame including the block ACK information received from the second STA is sent to the AP.

12. The method according to claim 1, wherein The first STA corresponds to a relay STA in relay transmission, and The second STA corresponds to the target STA in the relay transmission.

13. A device for a first station (STA) in a wireless local area network (WLAN) system, the device comprising: at least one transceiver; as well as at least one processor connected to the at least one transceiver, Wherein, the at least one processor is configured to: receiving, from an access point AP, a first aggregated MAC protocol data unit A-MPDU including data to be sent to a second STA; sending an acknowledgment ACK frame for the first A-MPDU to the AP; and sending a second A-MPDU including the data to the second STA, wherein the ACK frame includes ACK information indicating whether to check at least one MAC header included in the first A-MPDU, and The ACK information is based on an ACK policy indicated by an ACK policy related field and at least one other field included in the first A-MPDU.

14. A method performed by an access point (AP) in a wireless LAN system, the method comprising: Sending to the first station STA an aggregated MAC protocol data unit A-MPDU including data to be sent to the second STA; as well as receiving an ACK frame for the A-MPDU from the first STA, The ACK frame includes ACK information indicating whether to check at least one MAC header included in the A-MPDU, and The ACK information is based on an ACK policy indicated by an ACK policy related field and at least one other field included in the A-MPDU.

15. A device for an access point (AP) in a wireless local area network (WLAN) system, the device comprising: at least one transceiver; as well as at least one processor connected to the at least one transceiver, Wherein, the at least one processor is configured to: sending, to the first station STA, an aggregated MAC protocol data unit A-MPDU including data to be sent to the second STA; and receiving an ACK frame for the A-MPDU from the first STA, The ACK frame includes ACK information indicating whether to check at least one MAC header included in the A-MPDU, and The ACK information is based on an ACK policy indicated by an ACK policy related field and at least one other field included in the A-MPDU.

16. A processing unit configured to control a station (STA) in a wireless local area network (WLAN) system, the processing unit comprising: at least one processor; as well as At least one computer memory operatively connected to the at least one processor and storing instructions for executing the method according to any one of claims 1 to 12 upon being executed by the at least one processor.

17. At least one non-transitory computer-readable medium storing at least one instruction, wherein: The at least one instruction is executed by at least one processor to control a device to perform the method according to any one of claims 1 to 12 in a wireless local area network (WLAN) system.

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