Method and apparatus for priority-based channel access in wireless LAN system

Abstract

The present disclosure relates to a method and apparatus for priority-based channel access in a wireless local access network (LAN) system. The method according to an embodiment of the present disclosure is performed by a station (STA) of a wireless local access network (LAN) system, the method comprising the steps of: receiving a management frame including a priority value (PV) threshold value; on the basis of the PV threshold value, identifying whether or not contention-based channel access is allowed; when the contention-based channel access is allowed, determining an access PV (APV) within a PV range; and on the basis of the PV threshold value and the APV, transmitting a signal or frame associated with the contention-based channel access after channel sensing.

Description

Method and device for priority-based channel access in a wireless LAN system

[0001] The present disclosure relates to a wireless LAN network system. More specifically, the present disclosure relates to a method and device for priority-based channel access.

[0002] A wireless local area network (WLAN), also known as Wireless Fidelity (Wi-Fi), is a network that allows users to access the Internet via mobile devices or laptops within a certain distance from an access point (AP). WLAN technology continues to evolve with the rise of the Internet and the expansion of the smartphone market, and WLAN is used to provide high-speed data services to entire cities, including schools, airports, hotels, and offices.

[0003] The WiFi Alliance defines WiFi as a wireless local area network (WLAN) product based on the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standards. IEEE 802.11a and b, published in 1997 and 1999 respectively, are standards that utilize the unlicensed bands at 2.4 GHz and 5 GHz, with IEEE 802.11b providing a transmission rate of 11 Mbps and IEEE 802.11a providing a transmission rate of 54 Mbps. IEEE 802.11g applies orthogonal frequency-division multiplexing (OFDM) at 2.4 GHz to provide a transmission rate of 54 Mbps. IEEE 802.11n uses multiple input multiple output OFDM (MIMO-OFDM) to provide a transmission rate of 300 Mbps using four spatial streams. IEEE 802.11n supports channel bandwidths up to 40 MHz, in which case it provides a transmission rate of 600 Mbps.

[0004] Afterwards, the IEEE 802.11ac standard was introduced, which supports up to 160 MHz bandwidth, 8 spatial streams, and a speed of up to 1 Gbit / s, and IEEE 802.11ax, which provides multi-user MIMO (MU-MIMO) in both uplink and downlink and supports spatial frequency reuse, dynamic fragmentation, etc. Afterwards, 802.11be is being studied, which supports up to 320 ultra-wide channels, multi-link operation, 4kQAM, etc., and aims to theoretically implement a speed of 46 Gbps.

[0005] 802.11e defined the enhanced distributed channel access (EDCA) scheme to ensure appropriate quality of service (QoS) and improve the efficiency and performance of wireless networks by mapping access categories (ACs) based on priority for various types of traffic. However, when multiple connections for relatively high-priority traffic occur, network congestion and increased latency can occur within EDCA competition. Therefore, methods and devices are needed to address these issues.

[0006] According to one embodiment of the present disclosure, a method performed by a station (STA) of a wireless local access network (LAN) system is provided. The method comprises the steps of: receiving a management frame including a priority value (PV) threshold; identifying, based on the PV threshold, whether contention-based channel access is allowed; determining, if the contention-based channel access is allowed, an access PV (APV) within a PV range; and transmitting, after channel sensing, a signal or frame associated with the contention-based channel access based on the PV threshold and the APV.

[0007] According to one embodiment of the present disclosure, a method performed by an access point (AP) of a wireless LAN system is provided. The method comprises the steps of: determining whether to allow contention-based channel access of an STA; generating a PV threshold based on the determination result; transmitting a management frame including the PV threshold; and, if the contention-based channel access is allowed, receiving a signal or frame associated with the contention-based channel access.

[0008] According to one embodiment of the present disclosure, an STA of a wireless LAN system is provided. The STA includes: at least one transceiver; at least one processor communicatively connected to the at least one transceiver; and a memory communicatively connected to the at least one processor, the memory storing instructions executable by the at least one processor individually or in any combination, such that the STA receives a management frame including a priority value (PV) threshold through the transceiver, identifies whether contention-based channel access is allowed based on the PV threshold, determines an access PV (APV) within a PV range if the contention-based channel access is allowed, and transmits a signal or frame associated with the contention-based channel access through the transceiver after channel sensing based on the PV threshold and the APV.

[0009] According to one embodiment of the present disclosure, an AP of a wireless LAN system is provided. The AP includes: at least one transceiver; at least one processor communicatively connected to the at least one transceiver; and a memory communicatively connected to the at least one processor, the memory storing instructions that are executable individually or in any combination of the at least one processor, such that the AP determines whether to allow contention-based channel access of a station (STA), generates a PV (priority value) threshold based on a result of the determination, transmits a management frame including the PV threshold through the transceiver, and, if the contention-based channel access is allowed, receives a signal or frame associated with the contention-based channel access through the transceiver.

[0010] According to various embodiments of the present disclosure, congestion among relatively high-priority traffic can be alleviated and delays reduced in a wireless LAN network system. Furthermore, according to various embodiments of the present disclosure, network congestion can be efficiently controlled by introducing scalable signal transmission criteria and / or parameters.

[0011] The effects that can be obtained from various embodiments of the present disclosure are not limited to the effects mentioned above, and other effects not mentioned can be clearly derived and understood by a person having ordinary skill in the art based on the detailed description below.

[0012] Figure 1 is a diagram illustrating an example of a wireless communication network.

[0013] FIG. 2 is a diagram illustrating an example of the structure of an electronic device that performs WLAN connection.

[0014] Figure 3 is a diagram illustrating an example of a link setup process of a typical wireless LAN.

[0015] FIG. 4 is a diagram illustrating an example of a hidden node and an exposed node and an example of an RTS and a CTS for solving the problem of a hidden node and an exposed node.

[0016] Figure 5 is a diagram illustrating an example of a frame structure used in an IEEE 802.11 system.

[0017] Figure 6 is a drawing showing an example of NAV settings.

[0018] Figure 7 is a diagram illustrating an example of TXOP.

[0019] Figure 8 is a diagram illustrating an EDCA scheme that separates competition between STAs with high priority traffic from general competition.

[0020] Figure 9 is a diagram illustrating a conceptual diagram of an additionally improved EDCA+ method.

[0021] Figure 10 is a diagram illustrating a scenario in which an AP and an STA with high priority traffic are allowed to access a channel via EDCA+.

[0022] Figure 11 is a diagram illustrating a scenario in which an STA is not allowed to access a channel via EDCA+.

[0023] Figure 12 is a diagram illustrating a scenario where an AP and an STA with high priority traffic are allowed to access a channel via EDCA+, but contention is controlled by additional intervention from the AP.

[0024] Figure 13 is a diagram illustrating a scenario in which an STA with high priority traffic is allowed to access a contention-based channel through short-term control of an AP.

[0025] Figure 14 is a flowchart illustrating the operation of STA.

[0026] Figure 15 is a flowchart illustrating the operation of the AP.

[0027] Figure 16 is a diagram illustrating a conceptual diagram of a method for controlling contention-based channel access based on LAC.

[0028] FIG. 17 is a diagram illustrating various examples of a method for controlling contention-based channel access based on LAC.

[0029] Figure 18 is a diagram illustrating a scenario for controlling contention-based channel access based on LAC and time offset.

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

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

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

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

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

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

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

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

[0038] The exemplary embodiments are described below solely for simplicity with respect to wireless LAN systems. It should be understood that the exemplary embodiments are equally applicable to other wireless networks (e.g., cellular networks, pico-networks, femto-networks, satellite networks), as well as systems that utilize signals of one or more wired standards or protocols (e.g., Ethernet and / or HomePlug, PLC standards). As used herein, the terms WLAN and Wi-Fi® may include communications governed by the IEEE 802.11 family of standards, BLUETOOTH®, HiperLAN (a set of wireless standards primarily used in Europe and comparable to the IEEE 802.11 standards), and other technologies with relatively short radio ranges. Accordingly, the terms WLAN and WiFi may be used interchangeably herein. Additionally, while described below with respect to an infrastructure WLAN system including one or more APs and a plurality of wireless stations (STAs), the exemplary embodiments are equally applicable to other WLAN systems including, for example, multiple WLANs, peer-to-peer (or independent basic service set) systems, Wi-Fi Direct systems, and / or hotspots.

[0039] Additionally, while the present disclosure describes the exchange of data frames between wireless devices, the exemplary embodiments may be applied to the exchange of any data unit, packet, and / or frame between wireless devices. Thus, the term frame may include any frame, packet, or data unit, such as, for example, protocol data units (PDUs), media access control (MAC) protocol data units (MPDUs), and physical layer convergence procedure (PLCP) protocol data units (PPDUs). The term A-MPDU may mean aggregated MPDUs. A wireless local area network, or WLAN network, below may be a network implementing at least one of the IEEE 802.11 family of wireless communication protocol standards, such as those defined by the IEEE 802.11-2016 standard or amendments thereto (including, but not limited to, 802.11ah, 802.11ad, 802.11ay, 802.11ax, 802.11az, 802.11ba, and 802.11be).

[0040] In the following description, numerous specific details are set forth, such as examples of specific components, circuits, and processes, to provide a thorough understanding of the present disclosure. The term "connected," as used herein, means directly connected or connected via one or more intervening components or circuits. The term "connected AP" refers to an access point with which a given wireless station is currently associated and / or connected (e.g., there is an established communications channel or link between the access point and the given wireless station). Furthermore, in the following description and for purposes of explanation, specific nomenclature is set forth to provide a thorough understanding of the exemplary embodiments. However, it will be apparent to one skilled in the art that such specific details may not be necessary to practice the exemplary embodiments. In other instances, well-known circuits and devices are shown in block diagram form to avoid obscuring the present disclosure.

[0041] The operating principles of the present disclosure are described in detail below with reference to the attached drawings. In the following description of the present disclosure, detailed descriptions of related known functions or configurations will be omitted if they are deemed to unnecessarily obscure the gist of the present disclosure. Furthermore, the terms described below are defined based on the functions of the present disclosure and may vary depending on the intent or custom of the user or operator. Therefore, their definitions should be based on the overall content of this specification.

[0042] Figure 1 is a diagram illustrating an example of a wireless communication network.

[0043] Referring to FIG. 1, a wireless communication network (100) may be an example of a wireless local area network (LAN), such as a Wi-Fi network. The wireless communication network (100) may include a plurality of wireless communication devices, such as an AP (102) and a plurality of STAs (stations, 104). Although only one AP (102) is illustrated, the wireless communication network (100) may also include a plurality of APs (102).

[0044] An STA is a logical entity that includes a MAC and a physical layer interface to a wireless medium, and includes an AP and a non-AP STA (Non-AP station). Among the STAs, a portable terminal operated by a user is a Non-AP STA, and when simply referred to as an STA, it also refers to a Non-AP STA. Hereinafter, an STA may refer to a non-AP STA. Each of the STAs (104) may be referred to as a terminal or a device. The term 'terminal' or 'device' used in this specification may be referred to as a mobile station (MS), user equipment (UE), user terminal (UT), wireless terminal, access terminal (AT), terminal, subscriber unit, subscriber station (SS), wireless device, wireless communication device, wireless transmit / receive unit (WTRU), mobile node, mobile, or other terms. Various embodiments of the terminal may include a cellular telephone, a smart phone having wireless communication capabilities, a personal digital assistant (PDA) having wireless communication capabilities, a wireless modem, a portable computer having wireless communication capabilities, a photographic device such as a digital camera having wireless communication capabilities, a gaming device having wireless communication capabilities, a music storage and playback appliance having wireless communication capabilities, an Internet appliance capable of wireless Internet access and browsing, as well as portable units or terminals incorporating combinations of such functions. In addition, the terminal may include, but is not limited to, a machine-to-machine (M2M) terminal, a machine type communication (MTC) terminal / device. In the present specification, the terminal may also be referred to as an electronic device or simply a device.

[0045] An AP (102) is an entity that provides access to a distribution system (DS) via a wireless medium to its associated STAs. An AP may also be called a centralized controller, a base station (BS), a Node-B, a base transceiver system (BTS), or a site controller.

[0046] An exemplary coverage area (106) of an AP (102) that may represent a basic service area (BSA) of a wireless communication network (100) is illustrated. The AP (102) periodically broadcasts beacon frames (beacon frames may be used interchangeably with beacon) containing a basic service set identifier (BSSID) to enable any STAs (104) within the wireless range of the AP (102) to associate or re-associate with the AP (102) and establish or maintain a separate communication link (108) (or may be referred to as a Wi-Fi link) with the AP (102). The AP (102) may provide access to external networks for various STAs (104) within the WLAN via the separate communication links (108).

[0047] A single AP (102) and an associated set of STAs (104) may be referred to as a basic service set (BSS) managed by the individual AP (102). The BSS may be identified to users by a service set identifier (SSID), as well as to other devices by the BSSID, which may be the MAC address of the AP (102).

[0048] BSS can be categorized into infrastructure BSS and independent BSS (IBSS). The BSS illustrated in Figure 1 is an IBSS, but an infrastructure BSS (not shown) can also be established. An infrastructure BSS includes one or more STAs and an AP. In principle, communication between non-AP STAs in an infrastructure BSS occurs via the AP. However, if a direct link is established between non-AP STAs, direct communication between non-AP STAs is also possible.

[0049] Multiple infrastructure BSSs can be interconnected via a DS. Multiple BSSs connected via a DS are called an extended service set (ESS). STAs within an ESS can communicate with each other, and within the same ESS, STAs can seamlessly move from one BSS to another while maintaining seamless communication.

[0050] A DS is a mechanism that connects multiple APs. It doesn't necessarily have to be a network, and there are no restrictions on its form as long as it can provide a certain distribution service. For example, a DS could be a wireless network, such as a mesh network, or a physical structure that connects APs.

[0051] Additionally, the AP (102) and the STA (104) may be referred to as AP-MLD (access point multi-link device) and STA-MLD, respectively. This may mean that the AP and the STA can support multi-link operation.

[0052] Below is an example of a hierarchical structure according to the 802.11 standard.

[0053] The 802.11 standard document is developing the MAC and PHY protocols corresponding to Wi-Fi wireless access technology. The data link layer (DLL) includes the MAC sublayer, which is responsible for media access control, and receives packets from the upper layer, 802.1X Port Filtering, through the MAC_SAP interface, and configures them into IEEE 802.11 MAC frames and transmits them to the physical layer. The physical layer includes the PLCP (physical layer convergence procedure) sublayer and the PDM (physical medium dependent) sublayer, and the PLCP sublayer is responsible for configuring the IEEE 802.11 MAC frame configured in the MAC sublayer into a PLCP frame. The PLCP frame is then transmitted to the opposite terminal through the PMD sublayer.

[0054] Various management frames that manage Wi-Fi wireless access are not transmitted at the upper layer of 802.1X. These management frames are transmitted as requests and responses between the SMEs (station management entities) located within each terminal. The SME is a layer-independent entity that may exist within a separate management plane or may appear to be off to the side. For example, if an AP wants to form a BSS, the AP instructs the transmission of a beacon through the MLME_SAP interface, namely, the MLME-START.request and MLME-START.confirm primitives. If an STA wants to associate with the AP, the STA instructs the transmission of an association Request / Response frame through the MLME-ASSOCIATE.request, MLME-ASSOCIATE.response, MLME-ASSOCIATE.confirm, and MLME-ASSOCIATE.indication primitives. Meanwhile, if SME wants to set operating parameter values ​​related to the physical layer, it can set various physical layer parameter values ​​through the PLCP_SAP interface.

[0055] FIG. 2 is a diagram illustrating an example of the structure of an electronic device that performs WLAN connection.

[0056] Referring to FIG. 2, an electronic device (200) may be connected to an AP (210), and the electronic device (200) may include a processor (230) and a communication module (220). The electronic device (200) may be the STA (104) of FIG. 1, in which case the electronic device (200) may be connected to the AP (210) as illustrated. Alternatively, the electronic device (200) may be the AP (102) of FIG. 1, in which case the electronic device may be connected to the STA (104) and / or another AP as illustrated in FIG. 1.

[0057] The communication module (220) can receive a communication signal from the outside or transmit a communication signal to the outside based on a Wi-Fi communication method (for example, IEEE Std 802.11TM). For example, the communication module (220) can operate based on IEEE 802.11ac, 802.11ax, 802.11be, or 802.11bn among Wi-Fi communication methods, and in particular, IEEE 802.11be or 802.11bn has improved performance by supporting a wider bandwidth, higher data throughput, and shorter delay time compared to IEEE 802.11ax.

[0058] The communication module (220) may include a transceiver (224) for transmitting and receiving data with an external device and a communication processor (222) (e.g., a communication processor (not shown) or a short-range wireless communication module (e.g., a Wi-Fi chipset)). According to various embodiments, the communication module (220) may further include a memory.

[0059] According to various embodiments, the transceiver (224) may convert a baseband transmit signal into a wireless signal or may convert a received wireless signal into a baseband receive signal.

[0060] According to various embodiments, the communication module (220) may further include, in addition to the transceiver (224) and the communication processor (222), components for OFDM or OFDMA (orthogonal frequency division multiple access), for example, a modulator, a digital-analog converter (D / A converter), a frequency converter, an A / D converter, an amplifier, and / or a demodulator.

[0061] Although not shown, according to various embodiments, the electronic device (200) may include at least one antenna module that is electrically connected to the communication module of the AP (210) and supports a communication protocol and / or frequency band supported by the communication module of the AP (210).

[0062] The communication processor (222) may control the transceiver (224) to form a communication connection with the AP (210). For example, the communication connection may include a Wi-Fi network. For example, the communication processor (222) may control the transceiver (224) to form a wireless connection with the AP (210) using a 2.4 GHz, 5 GHz, or 6 GHz band WLAN standard such as IEEE 802.11ac, 802.11ax, 802.11be, or 802.11bn. Alternatively, the communication processor (222) may control the transceiver (224) to form a wireless connection with the AP (210) using a 60 GHz band WLAN standard such as IEEE 802.11ad or 802.11ay. Additionally, a method of communicating between an electronic device (200) and an AP (210) using the WLAN standard may be referred to as a communication method based on the STA mode.

[0063] According to various embodiments, the processor (230) may include an application processor. The processor (230) may perform a specified operation of the electronic device (200) or control other hardware (e.g., a communication module (220)) to perform a specified operation.

[0064] According to various embodiments, the AP (210) may support an operation of transmitting packets to an external network and / or an operation of the plurality of electronic devices receiving packets from an external network based on a connection between a plurality of electronic devices (e.g., the electronic device (200)) and an external network (e.g., the Internet, an external LAN, or a cellular network).

[0065] For example, the AP (210) may be a wireless router. The AP (210) may be a dedicated wireless router or a general-purpose device supporting mobile hotspot functionality, and there are no limitations on its implementation. For example, the AP (210) may include the same components as the electronic device (200), such as a processor and / or a communication module. Furthermore, the AP (210) may transmit and receive data to and from an external device, such as a server. For example, the AP (210) may transmit at least a portion of the data received from the server to the electronic device (200).

[0066] If the electronic device (200) of FIG. 2 corresponds to the AP (102), the electronic device (200) may include a separate communication module for connection with an external network, although not shown. This communication module may be controlled by the processor (230) or by a separate processor. The separate communication module may include a transceiver and a processor, and may also include memory. In addition, the electronic device (200) may include a separate antenna module or wired connection device for connection with an external network.

[0067] Figure 3 is a diagram illustrating an example of a link setup process of a typical wireless LAN.

[0068] For an STA to set up a link and transmit and receive data on a network, it must first discover the network, perform authentication, establish an association, and complete security authentication procedures. The link setup process can also be referred to as the session initiation process or session setup process. Furthermore, the discovery, authentication, association, and security setup processes of the link setup process can be collectively referred to as the association process.

[0069] Referring to FIG. 3, an STA (300) can perform a network discovery operation. The network discovery operation may include a scanning operation of the STA (300). That is, in order for the STA (300) to access a network, it must search for a network it can participate in. Before joining a wireless network, the STA (300) must identify a compatible network. The process of identifying networks existing in a specific area is called scanning.

[0070] There are two types of scanning methods: active scanning and passive scanning. In active scanning, an STA (300) performing scanning transmits a probe request frame (322) to search for APs in the vicinity while moving between channels and waits for a response. A responder transmits a probe response frame (324) to the STA that transmitted the probe request frame in response to the probe request frame. Here, the responder may be an AP or STA that last transmitted a beacon frame in the BSS of the channel being scanned. In FIG. 3, an example of a BSS that becomes a responder is shown because an AP (310) transmits a beacon frame (320), and in an IBSS, STAs within the IBSS take turns transmitting beacon frames, so the responder is not constant. For example, if an STA transmits a probe request frame on channel 1 and receives a probe response frame on channel 1, the STA can store BSS-related information included in the received probe response frame and move to the next channel to perform scanning in the same manner.

[0071] The scanning operation can also be performed in a passive scanning manner. In passive scanning, the STA performing the scanning moves through channels and detects beacon frames. A beacon frame is one of the management frames in IEEE 802.11, and is periodically transmitted to announce the presence of a wireless network and to enable the STA performing the scanning to find the wireless network and participate in the wireless network. FIG. 3 illustrates an example of a BSS in which an AP (310) periodically transmits a beacon frame (320) to an STA (300), and in an IBSS, STAs within the IBSS take turns transmitting beacon frames. When the STA performing the scanning receives a beacon frame, it stores information about the BSS included in the beacon frame and moves to another channel, recording the beacon frame information on each channel. Comparing active and passive scanning, active scanning has the advantage of lower delay and power consumption than passive scanning.

[0072] After the STA (300) discovers the network, an authentication process may be performed. This authentication process may be referred to as the first authentication process to clearly distinguish it from the security setup operation (350) described below. The authentication process includes a process in which the STA (300) transmits an authentication request frame (330) to the AP (310), and in response, the AP (310) transmits an authentication response frame (332) to the STA (300). The authentication frame used for the authentication request / response corresponds to a management frame.

[0073] The authentication frame may include information such as an authentication algorithm number, an authentication transaction sequence number, a status code, a challenge text, a Robust Security Network (RSN), and a Finite Cyclic Group. These are just some examples of information that may be included in an authentication request / response frame, and may be replaced with other information or include additional information.

[0074] The AP (310) may determine whether to allow authentication for the STA based on information included in the received authentication request frame. The AP (310) may provide the result of the authentication process to the STA (300) via an authentication response frame.

[0075] After the STA is successfully authenticated, an association process can be performed. The association process includes a process in which the STA (300) transmits an association request frame (340) to the AP (310), and in response, the AP (310) transmits an association response frame (342) to the STA (300).

[0076] For example, the association request frame may include information related to various capabilities, such as beacon listen interval, SSID, supported rates, supported channels, robust security network (RSN), mobility domain, supported operating classes, traffic indication map broadcast request, and interworking service capabilities.

[0077] For example, the association response frame may include information related to various capabilities, status codes, association ID (AID), supported rates, enhanced distributed channel access (EDCA) parameter sets, received channel power indicator (RCPI), received signal to noise indicator (RSNI), mobility domains, timeout interval (association comeback time), overlapping BSS scan parameters, TIM broadcast response, QoS maps, etc.

[0078] These are just some examples of information that may be included in a request / response frame, and may be replaced by other information or include additional information.

[0079] Although not shown, after the STA successfully associates with the network, a security setup process may be performed. The security setup process may be referred to as an authentication process via a robust security network association (RSNA) request / response, the authentication process (330) may be referred to as a first authentication process, and the security setup process may also be referred to as an authentication process.

[0080] The security setup process may include, for example, a private key setup process through a four-way handshaking using an extensible authentication protocol over LAN (EAPOL) frame, or may be performed according to a security method not defined in the IEEE 802.11 standard.

[0081] Below we describe the media access control protocol provided by 802.11.

[0082] In wireless LAN systems based on IEEE 802.11, the basic access mechanism of MAC is based on the distributed coordination function (DCF) that utilizes the carrier sense multiple access with collision avoidance (CSMA / CA) method. There are two methods for detecting carriers in DCF: physical carrier sense and virtual carrier sense. Physical carrier sense is a method in which the physical layer detects the channel status and notifies the MAC layer, and virtual carrier sense is a method in which the channel occupancy time is broadcast to neighboring stations to reserve the channel in advance. An STA or AP that has secured a transmission channel records and transmits this channel occupancy time within the RTS or / and CTS or data frame. Other STAs that receive this determine that the channel is busy during this time and do not compete for the channel, thereby avoiding collisions.

[0083] The physical carrier sensing method basically adopts a listen-before-talk access mechanism, and according to this type of access mechanism, the AP and / or STA can perform a clear channel assessment (CCA) to sense the wireless channel or carrier or medium for a predetermined time period before starting transmission. The predetermined time period is called an inter frame space (IFS) and can vary depending on the priority of the traffic to be transmitted. That is, the priority can be determined by the length of the time period, and the higher the priority packet, the shorter the time period can be.

[0084] The above IFS may include SIFS (short IFS), PIFS (PCF IFS), DIFS (DCF IFS), AIFS (arbitration IFS), EIFS (extended IFS), etc. The SIFS is the shortest time interval and may be mainly used as a waiting time for control information. The PIFS is a time interval of medium length and may be for a packet of medium priority (PIFS = SIFS + 1 slot time). The DIFS is the longest time interval compared to the SIFS and PIFS, has a low priority, and may be mainly used as a waiting time for checking whether a channel is in use (DIFS = SIFS + 2 slot time). That is, for example, an STA that wishes to perform transmission may listen to whether a channel is in use (or detect the channel) during the DIFS period. The AIFS may be defined as a dynamic frame interval by assigning a different AIFSN (AIFS number) to each AC (AIFS = SIFS + AIFSN * slot time). The above EIFS can be used when a frame transmission error occurs, and can prevent retransmission of the original frame or subsequent overuse of ACK frames (EIFS = SIFS+ACKTxTime+DIFS, where ACKTxTime is the time taken to transmit an ACK frame at the lowest speed).

[0085] Based on the sensing result, if the medium is determined to be in an idle state, the AP and / or STA initiate frame transmission through the medium. On the other hand, if the medium is detected to be in an occupied state, the AP and / or STA may not initiate its own transmission, but may wait for a delay period (e.g., a random backoff period) for medium access before attempting frame transmission. By applying a random backoff period, multiple STAs are expected to attempt frame transmission after waiting for different periods of time, thereby minimizing collisions.

[0086] However, since this DCF method does not consider the priority between STAs, it has a problem in that it is difficult to support various types of data transmission and QoS (Quality of Service), so the hybrid coordination function (HCF) was introduced. HCF is based on the DCF and the point coordination function (PCF). PCF is a polling-based synchronous access method that periodically polls all receiving APs and / or STAs so that they can receive data frames. HCF includes EDCA (enhanced distributed channel access), which is a contention-based channel access method, and HCCA (HCF controlled channel access), which is a contention-free method using a polling mechanism. In addition, HCF includes a medium access mechanism to improve the QoS of WLAN, and can transmit QoS data in both a contention period (CP) and a contention-free period (CFP).

[0087] According to EDCA, data has a user priority from 0 to 7 depending on the traffic type, and data arriving at the MAC layer is mapped to four access categories (ACs) based on these priorities. More specifically, AC_VO (voice) is used for voice traffic. Real-time communications, such as voice calls, require minimal delay, so they are given the highest priority to ensure fast transmission. AC_VI (video) is used for video streaming traffic. Since video streaming is also sensitive to delay, smooth playback can be ensured by giving it the second-highest priority after voice. AC_BE (best effort) is used for general data traffic. For example, traffic such as web surfing and email is relatively insensitive to delay and can be processed with a medium priority. Finally, AC_BK (background) is used for background traffic. Traffic for which delay is not critical, such as file downloads or background data transfers, can be processed with a low priority. The higher the priority, the higher the priority it has, and since AC has each AC parameter and backoff is performed using AC parameter values ​​that are set differently, data has different channel access priorities depending on the AC. AC parameters may include AIFS, CWmin, CWmax, and TXOP limit. The smaller the values ​​of AIFS and CWmin, the higher the priority it has, and accordingly, the shorter the channel access delay, so that data can use more bandwidth in a given traffic environment. When a collision occurs between STAs during frame transmission, the EDCA backoff process, which generates a new backoff counter, is similar to the existing DCF, and transmission according to traffic priority is guaranteed through EDCA parameters that include priorities for each AC.

[0088] FIG. 4 is a diagram illustrating an example of a hidden node and an exposed node and an example of an RTS and a CTS for solving the problem of a hidden node and an exposed node.

[0089] Figure 4 (a)(400) is an example of a hidden node. When STA A and STA B are communicating and STA C has information to transmit, STA A may determine that the medium is idle when performing carrier sensing before STA C sends data to STA B, even though STA A is transmitting the information to STA B. This is because STA A's transmission (i.e., medium occupancy) may not be sensed at STA C's location. In this case, STA B receives information from STA A and STA C simultaneously, resulting in a collision. In this case, STA A can be said to be a hidden node of STA C.

[0090] (b)(410) is an example of an exposed node. In a situation where STA B is transmitting data to STA A, STA C may have information to transmit to STA D. In this case, if STA C performs carrier sensing, it may determine that the medium is occupied due to the transmission of STA B. Accordingly, STA C must wait until the medium becomes idle even if it has information to transmit to STA D. However, in reality, STA A is outside the transmission range of STA C, so the transmission from STA C and the transmission from STA B may not collide from the perspective of STA A, and thus STA C unnecessarily waits until STA B stops transmitting. In this case, STA C can be called an exposed node of STA B.

[0091] In order to effectively utilize the collision avoidance mechanism in the above situation, short signaling packets such as RTS (request to send) and CTS (clear to send) can be utilized. An STA that wishes to transmit data transmits an RTS to an STA that will receive the data, and the receiving STA that receives the RTS responds to the transmitting STA with a CTS frame. The RTS and / or CTS between two STAs can be overheard by surrounding STA(s), allowing the surrounding STA(s) to consider whether information should be transmitted between the two STAs.

[0092] (c)(420) is an example of a method for solving the hidden node problem. Assume that both STA A and STA C want to transmit data to STA B. When STA A transmits an RTS to STA B, STA B transmits a CTS to STA A. STA C, which overhears the RTS and CTS, delays its medium access until STA A and STA B finish transmitting data, thereby avoiding collisions.

[0093] (d)(430) is an example of a method for solving the exposed node problem. STA B, which wants to transmit data to STA A, transmits an RTS, and STA A, which is to receive the data, can respond to the RTS by transmitting a CTS. In this case, if STA C receives only the RTS transmitted by STA B and does not receive the CTS transmitted by STA A, STA C can determine that STA A is outside the carrier sensing area of ​​STA C. In this case, STA C can determine that no collision will occur even if it transmits data to another STA (e.g., STA D), and can transmit the data.

[0094] Figure 5 is a diagram illustrating an example of a frame structure used in an IEEE 802.11 system.

[0095] The PPDU (physical layer protocol data unit) format can be composed of a short training field (STF), a long training field (LTF), a SIGNAL (SIG) field, and a data field. The most basic (e.g., non-HT (high throughput)) PPDU frame format can be composed of only the legacy-STF (L-STF), legacy-LTF (L-LTF), a SIG field, and a data field.

[0096] STF can be used for frame timing acquisition, automatic gain control (AGC), diversity detection, and coarse frequency / time synchronization. LTF can be used for fine frequency / time synchronization and channel estimation. The STF and LTF can be collectively called the PLCP preamble, which is a signal for OFDM physical layer synchronization and channel estimation.

[0097] The SIG field can be used to transmit control information for demodulation and decoding of the data field. The SIG field can include information about the data rate and data length. Additionally, the SIG field can include a parity bit, a SIG TAIL bit, etc.

[0098] The data field may include a SERVICE field, a physical layer service data unit (PSDU), a PPDU TAIL bit, and, if necessary, padding bits. Some bits of the SERVICE field may be used for a descrambler at the receiver. The PSDU corresponds to an MPDU (mac protocol data unit) defined at the MAC layer and may contain data generated / used by upper layers. The PPDU TAIL bit may be used to return the encoder to a 0 state. The padding bit may be used to adjust the length of the data field to a predetermined unit.

[0099] MPDU is defined according to various MAC frame formats, and a basic MAC frame consists of a MAC header, frame body, and FCS (frame check sequence). MAC frame is composed of MPDU and can be transmitted / received through PSDU of the data part of PPDU format.

[0100] The MAC header is defined as an area that includes a frame control field, a duration / ID field, an address 1 field, an address 2 field, an address 3 field, a sequence control field, an address 4 field, a QoS control field, and an HT control field.

[0101] The Frame Control field contains information about the characteristics of the corresponding MAC frame. The Segment / Identifier field may be implemented to have different values ​​depending on the type and subtype of the corresponding MAC frame.

[0102] The Address 1 field to the Address 4 field are used to indicate the BSSID, source address (SA), destination address (DA), transmitting address (TA) indicating the transmitting STA address, and receiving address (RA) indicating the receiving STA address.

[0103] The sequence control field is set to include a sequence number and a fragment number. The sequence number can indicate the sequence number assigned to the corresponding MAC frame. The fragment number can indicate the number of each fragment of the corresponding MAC frame.

[0104] The QoS Control field contains information related to QoS. The QoS Control field may be included when the Subtype subfield indicates a QoS data frame. The HT Control field contains control information related to HT and / or VHT transmission and reception techniques.

[0105] The frame body is defined as the MAC payload, contains the data to be transmitted from the upper layer, and has a variable size. For example, the maximum MPDU size is 11,454 octets, and the maximum PPDU size can be 5.484 ms.

[0106] FCS is defined as a MAC footer and is used to detect errors in MAC frames.

[0107] The first three fields (Frame Control, Segment / Identifier, and Address 1) and the last field (FCS) constitute the minimum frame format and are present in all frames. The remaining fields may only be present in certain frame types.

[0108] Below is a description of the network allocation vector (NAV) used in wireless LAN networks.

[0109] As mentioned above, the CSMA / CA mechanism includes virtual carrier sensing in addition to physical carrier sensing, in which the AP and / or STA directly sense the medium. Virtual carrier sensing is intended to address potential issues in medium access, such as the hidden node problem. For virtual carrier sensing, the MAC of the wireless LAN system can utilize NAV. NAV is a value that indicates to other APs and / or STAs the remaining time until the medium becomes available, by the AP and / or STA currently using or authorized to use the medium. Therefore, the value set as NAV corresponds to the period during which the medium is scheduled to be used by the AP and / or STA transmitting the frame, and the STA receiving the NAV value is prohibited from accessing the medium during the period. NAV can be set, for example, according to the value of the duration field of the MAC header of the frame.

[0110] Figure 6 is a drawing showing an example of NAV settings.

[0111] Referring to FIG. 6, a source STA (source STA, 600) transmits an RTS frame after DIFS, and a destination (destination) (610) transmits a CTS frame after SIFS. The destination STA designated as the receiver through the RTS frame does not set an NAV. Some of the remaining STAs (620) may receive the RTS frame and set an NAV (630), and some may receive the CTS frame and set an NAV (640).

[0112] If a CTS frame (e.g., PHY-RXSTART.indication primitive) is not received within a certain period of time from the time when the RTS frame is received (e.g., the time when the MAC receives the PHY-RXEND.indication primitive corresponding to the RTS frame), STAs that have set or updated the NAV through the RTS frame may reset the NAV (e.g., to 0) (or this case may be referred to as NAVtimeout). The certain period of time may be (2*aSIFSTime + CTS_Time + aRxPHYStartDelay + 2*aSlotTime), and this may be referred to as NAVtimeout period. CTS_Time may be calculated based on the length of the CTS frame and the data rate indicated by the RTS frame.

[0113] In Fig. 6, for convenience, setting or updating NAV through an RTS frame or a CTS frame is illustrated, but NAV setting / resetting / updating may also be performed based on various other frames, such as a non-HT PPDU, HT PPDU, VHT PPDU, or an interval field of a HE PPDU (for example, an interval field in a MAC header of a MAC frame).

[0114] 802.11ax also introduces basic NAV and intra-BSS NAV. Basic NAV is always set by frames transmitted by APs or STAs other than itself (mandatory), and intra-BSS NAV can be optionally set by frames transmitted by the BSS to which the AP or STA belongs. An AP or STA can access the medium when both NAV timers have expired (or after all NAV time intervals have elapsed).

[0115] Below, we describe TXOP (transmission opportunity). TXOP is a new feature introduced in the 802.11e MAC to ensure QoS and improve channel utilization. To ensure QoS, TXOP can be used to assign priority transmission opportunities when two or more packets fall into the same access category (AC).

[0116] Figure 7 is a diagram illustrating an example of TXOP.

[0117] STAs participating in QoS transmission can obtain TXOPs, which allow them to transmit traffic for a certain period of time, using two channel access methods: EDCA and HCCA. TXOPs can be acquired either by successfully competing in EDCA or by receiving a QoS CF-Poll frame from the AP. The former is called an EDCA TXOP, and the latter a Polled TXOP. In this way, the concept of TXOP can be used to grant a certain amount of time for a STA to transmit a frame, or to forcibly limit the transmission time.

[0118] The transmission start time and maximum transmission time of TXOP are determined by the AP, which is notified to the STA by a beacon frame for EDCA TXOP and by a QoS CF-Poll frame for Polled TXOP.

[0119] NAV can be understood as a kind of timer to protect the TXOP of a transmitting STA (e.g., a TXOP holder). An STA can protect the TXOP of another STA by not performing channel access while the NAV set for itself is valid. In the current wireless LAN system, the TXOP duration is set through the duration field of the MAC header. That is, the TXOP holder and the TXOP responder (e.g., the Rx STA) transmit the entire TXOP information required for transmitting and receiving frames by including it in the duration field of the frames they transmit and receive. Third-party STAs that are not the TXOP holder or the TXOP responder (e.g., third-party STAs) check the duration field of the frames exchanged between the TXOP holder and the TXOP responder, and postpone channel use until the NAV period by setting / updating the NAV.

[0120] Below, the primary channel and secondary channel are described. The primary channel is a common channel operated by all STAs that are members of the BSS. For example, in a 20 MHz, 40 MHz, 80 MHz, 160 MHz, or 80 + 80 MHz BSS, the primary channel may be the primary 20 MHz channel. In this case, the 40 and 80 MHz channels that include the primary 20 MHz channel may be referred to as the primary 40 and 80 MHz channels, and the primary channel may generally be referred to as the primary 20 MHz channel.

[0121] A secondary channel is a channel associated with a primary channel and is used to create a wider channel than the primary channel. For example, in a 40 MHz, 80 MHz, or 160 MHz BSS, the 40 MHz channel may be the sum of a primary 20 MHz channel and a secondary 20 MHz channel, the 80 MHz channel may be the sum of a primary 40 MHz channel and a secondary 40 MHz channel, and the 160 MHz channel may be the sum of a primary 80 MHz channel and a secondary 80 MHz channel.

[0122] Below we describe the 802.11be standard. 802.11be, also known as EHT (extremely high throughput), operates in the 2.4, 5, and 6 GHz bands and is being developed to provide speeds up to 46 Gbps, which is 4.8 times faster than WiFi 6, by introducing 320 MHz of bandwidth, 4096QAM, multiple resource units (RUs), and multi-link operation (MLO), while providing low latency and high network throughput. Specifically, 802.11be provides a wide bandwidth of 320 MHz in the 6 GHz band, can transmit data via MU-MIMO with 16 spatial streams in both the uplink and downlink, and can achieve high transmission efficiency by adopting 4096QAM. In addition, it has the characteristics of increasing spectrum efficiency by flexibly performing spectrum resource scheduling through multiple RUs, and simultaneously transmitting and receiving data in various frequency bands and channels through multi-link operation.

[0123] Below, we describe TXOP sharing. In order to improve the efficiency of wireless channels in 802.11ac, MU-MIMO MAC technology was introduced, which can simultaneously transmit different frames from an AP to multiple STAs using spatially divided multi-channels. At this time, the AP determines the destination STA and the frame to be transmitted for each channel during the TXOP period based on the AC (access category, or priority) of the frame to be transmitted, and transmits the determined multiple frames to multiple STAs. Recently, TXOP sharing between APs has been studied. Through TXOP sharing between APs, an AP with a TXOP can share its TXOP with other APs, thereby efficiently utilizing frequency and spatial resources, increasing network throughput and reducing latency.

[0124] Next, we'll discuss overlapping basic service sets (OBSS). Existing wireless LAN networks experience significant performance degradation, including throughput, as users increase. This is because wireless LAN systems fundamentally utilize CSMA / CA, a time-division access control scheme. When a neighboring network is detected, the system divides the frequency resources in the same band by the amount of time the neighboring network is active.

[0125] Currently, there are many cases where multiple APs are operating in a specific area, and in this case, the performance of the wireless LAN network deteriorates due to overlapping coverage between APs. This is because the APs of each BSS and the STAs connected to the APs are affected by the signals of the neighboring BSS, resulting in interference by the neighboring BSS, which in turn causes a decrease in the transmission rate due to collisions between signals transmitted at the same time. BSSs that can affect signal transmission in this way (or whose coverage overlaps) can be referred to as overlapping BSSs (OBSS). To solve this problem, interference avoidance technologies that divide the bands available to each user so that they do not overlap or perform channel switching to unused channels, as well as interference alignment technologies that reduce the impact of interference even when using the same band, are being studied.

[0126] Figure 8 is a diagram illustrating an EDCA scheme that separates competition between STAs with high priority traffic from general competition.

[0127] EDCA is currently the primary channel access mechanism in wireless LAN networks. However, because conventional EDCA provides channel access opportunities to all traffic types, even high-priority ACs can struggle to secure TXOPs due to competition with lower-priority EDACFs (EDCA functions). In other words, conventional EDCA fails to sufficiently separate traffic, which can lead to latency spikes.

[0128] To address this issue, a method is being discussed in which EDCA contention is conducted only between STAs with high priority traffic (e.g., AC_VO). For example, STAs with high priority traffic can transmit a special signal (e.g., a defer signal, DS) or frame at the start of a contention period, thereby forcing STAs that have not transmitted the DS or frame to set the CCA to “busy” and not participate in the contention period. Thereafter, STAs that have transmitted the DS or frame can only compete with those STAs in the immediately following contention period. In the present disclosure, for the convenience of the technology, such a method may be referred to as EDCA+ (EDCA Plus) or HiP EDCA (High Priority EDCA), but the scope of the present disclosure is not limited by such terms, and terms such as general EDCA or contention-based channel access may be used interchangeably.

[0129] Referring to FIG. 8, one or more STAs (801, 802, 803, 804) may set up a link to a network and be associated with an AP. Here, STA1 (801) and STA2 (802) may be conventional stations or STAs with relatively low priority traffic, and STA3 (803) and STA4 (804) may be stations supporting EDCA+ or HiP EDCA and may be STAs with relatively high priority traffic (e.g., AC_VO).

[0130] At the end of the last frame transmission (811) of the corresponding TXOP of STA1 (801) in the previous TXOP (810), STAs (801, 802, 803, 804) may perform CCA (clear channel assessment) to sense the wireless channel or carrier or medium for a predetermined time period in the EDCA contention period (820). For example, STA1 (801) and STA2 (802) may perform sensing during AIFS (=SIFS+AIFSN*slot time), and STA3 (803) and STA4 (804) may perform sensing during a period shorter than the AIFS of STA1 (801) and STA2 (802) (e.g., DIFS).

[0131] If the sensing results of STA3 (803) and STA4 (804) determine that the channel is idle, STA3 (803) and STA4 (804) may transmit a DS or frame (821, 822). STA1 (801) and STA2 (802), which have not transmitted the DS or frame, may determine that the channel state is “busy” and may not participate in the contention.

[0132] STA3 (803) and STA4 (804) can each generate (823, 824) an arbitrary backoff (BO) counter between a specific section (0 to 7). In this drawing, the case where the value of the BO counter of STA3 (803) is '4' and the value of the BO counter of STA4 (804) is '5' is illustrated as an example. STA3 (803) and STA4 (804) can decrease the BO counter by 1 every 1 slot time. Thereafter, since the value of the BO counter of STA3 (803) reaches '0' before the value of the BO counter of STA4 (804), STA3 (803) can acquire a TXOP (830) and transmit (831) a PPDU.

[0133] The aforementioned EDCA+ or HiP EDCA scheme can prioritize the transmission of high-priority traffic over general traffic, thereby reducing overall network delay. However, in situations where multiple connections for relatively high-priority traffic occur, these STAs may still transmit DS or frames simultaneously, resulting in network congestion and increased delay within the contention. Therefore, the present disclosure proposes a method and device that can reduce network congestion and delay through AP control in scenarios where multiple connections for high-priority traffic occur.

[0134] Figure 9 is a diagram illustrating a conceptual diagram of an additionally improved EDCA+ method.

[0135] Referring to FIG. 9, at step 900, the AP may transmit a management frame to STAs within the network. The management frame may be a beacon frame periodically broadcast by the AP, and may include one or more parameters for EDCA+. For example, the management frame may include at least one or a combination of the following parameters:

[0136] - Traffic type (e.g., Access Class or Traffic identifier (TID)): The AP may select the lowest AC (LAC) for which contention-based channel access is allowed. For example, if the AP selects AC_VI as the LAC for which contention-based channel access is allowed, contention-based channel access may be allowed for AC_VO and AC_VI. In another embodiment, the AP may provide multiple ACs for which contention-based channel access is allowed.

[0137] - PV (priority value) threshold: The AP can determine an appropriate PV threshold within a certain range within which contention-based channel access is permitted in order to control access. The PV threshold may be applied universally regardless of AC, or may be set differently for each AC. The AP and / or STA select a random PV (e.g., access PV, APV) for access within a certain range, and can participate in contention if the selected APV is less than, equal to, or less than the PV threshold. Therefore, if the PV threshold is set to 0, it may mean that contention-based channel access of the STA is not permitted. Meanwhile, the range for the AC to select the PV threshold and the range for the AP and / or STA to select the APV may be the same or different.

[0138] - PV range: The AP can transmit information about the range from which PV can be selected in the management frame. For example, information about the PV range may include the minimum value of PV (PV min ) and the maximum value of PV (PV max ) or may be composed of information about the maximum value of the PV (or the length of the PV range) assuming that the minimum value of the PV is 0. In another embodiment, the PV range may be fixed in the system, in which case the AP may not transmit information about the PV range. Alternatively, if there are multiple PV thresholds, information about multiple PV ranges may be provided. As described above, the AP and / or STA may select an APV within the set PV range.

[0139] - Number of retransmissions: The AP can include information about the number of retransmissions allowed for EDCA+ access in the management frame and transmit it. For example, if the value of the number of retransmissions is set to 1, transmission of specific traffic that has failed more than once can participate in EDCA+. This method can reduce the delay of the entire network because additional priority can be given to traffic that has failed more than once and thus has a shorter remaining delay tolerance. Alternatively, the AP can set the value of the number of retransmissions to 0 or not transmit information about the number of retransmissions.

[0140] - Size of backoff window (or contention window) for EDCA+: The AP can separately set the interval of the backoff counter used for EDCA+ access. For example, if the LAC that allows contention-based channel access is AC_VI, contention-based channel access for AC_VO and AC_VI may be allowed, so that AC_VO may be given additional priority, and the backoff window for AC_VO may be shorter than the backoff window for AC_VI. In other words, if access to multiple ACs may be allowed, the sizes of multiple corresponding backoff windows may be provided. In this case, the size of the backoff window may be equal to or smaller than the EIFS.

[0141] If the above PV threshold is not 0, the STA may be allowed to access a contention-based channel. In step 910, the STA may determine an APV within an arbitrary section or PV range provided by the AP, and compare the APV with the PV threshold. If the APV is less than, equal to, or less than the PV threshold, the STA may transmit a DS or frame after DIFS, and then in step 920, the STA may access the channel using a contention scheme (e.g., EDCA / EDCA+ / Hip EDCA). If the APV is greater than, equal to, or greater than the PV threshold, the STA may not participate in this contention, but may determine a new APV or update the previous APV and compare it with the PV threshold during the next contention-based channel access. Here, the updated APV may be determined as a value obtained by subtracting a certain value from the previous APV, or as a value obtained by subtracting the PV threshold from the previous APV. The above operation may be repeated until the APV is less than, equal to, or less than the PV threshold.

[0142] Additionally, the AP may perform operations similar to those of the STA described above to avoid collisions between other AP(s) or between APs and STAs. For example, in step 910, the AP may determine an APV within a PV range having a maximum value smaller than a maximum value within a PV range equal to or smaller than a PV range provided to the STA, or within a PV range having a maximum value smaller than a PV range provided to the STA, and compare the APV with a PV threshold. The PV threshold may be the same value as the PV threshold provided to the STA, or may be a separate PV threshold value exchanged between the AP(s) (e.g., a value larger than the PV threshold provided to the STA). If the APV is smaller than, equal to, or smaller than the PV threshold, the AP may transmit a DS or frame after a DIFS, and then in step 920, the AP may access the channel using a contention scheme (e.g., EDCA / EDCA+ / Hip EDCA). If the APV is greater than, equal to, or greater than the PV threshold, the AP does not participate in this contention, but may determine a new APV or update the previous APV and compare it with the PV threshold during the next contention-based channel connection. The updated APV may be determined as a value obtained by subtracting a certain value from the previous APV or as a value obtained by subtracting the PV threshold from the previous APV. The above operation may be repeated until the APV is less than, equal to, or less than the PV threshold.

[0143] On the other hand, if the PV threshold value above is 0, the STA's contention-based channel access is not allowed, and only the AP can access the channel. In step 930, the AP can transmit a DS or frame after PIFS or DIFS, and the frame can be a control frame (e.g., a trigger frame). If the AP wants to allow the STA's contention-based channel access again, it can update parameters such as the PV threshold value, and in this case, the STA can access the channel using a contention method (e.g., EDCA / EDCA+ / Hip EDCA) as in step 930 described above. Otherwise, if the AP does not update the parameters, the STA is still not allowed to access, and the AP and / or the STA can perform the existing general TXOP operation in step 940.

[0144] Thereafter, in step 950, the AP may adjust the PV threshold considering channel conditions, including overall delay within the network or delay of individual traffic. The operations of steps 900 to 950 may be repeated.

[0145] In the following Figures 10 to 13, it is described that APs and STA(s) within a network perform EDCA+ according to the above Figure 9 and the description thereof.

[0146] Figure 10 is a diagram illustrating a scenario in which an AP and an STA with high priority traffic are allowed to access a channel via EDCA+.

[0147] Referring to FIG. 10, one or more STAs (1001, 1002, 1003, 1004) may set up a link to a network and be associated with an AP (1000). Here, STA1 (1001) may be a conventional station or an STA with relatively low priority traffic, and STA2 (1002), STA3 (1003), and STA4 (1004) are stations that support EDCA+ or HiP EDCA, and STA2 (1002) may have AC_VI traffic, and STA3 (1003) and STA4 (1004) may each have AC_VO traffic.

[0148] AP (1000) may transmit (1005) a management frame to STAs (1001, 1002, 1003, 1004) within the network at a specific point in time. The management frame may be a beacon frame periodically broadcast by the AP, which may include one or more parameters for EDCA+ listed in the description of FIG. 9. In this drawing, it is assumed that AP (1000) transmits a beacon frame including at least one of PV threshold value = 3, PV range = [0, 10], and LAC = AC_VO.

[0149] STA2 (1002), STA3 (1003), and STA4 (1004) supporting EDCA+ or HiP EDCA can determine whether they can participate in EDCA+ based on the parameter(s) included in the beacon frame.

[0150] STA2 (1002) can determine (1006) not to participate in EDCA+ because it has traffic of AC_VI, which is a lower priority than LAC=AC_VO.

[0151] Since STA3 (1003) has traffic with AC_VO priority, which is the same as LAC=AC_VO, it can randomly select an APV within the range of PVs (if provided). If the APV selected by STA3 (1003) is 2, it is less than the provided PV threshold value = 3, so STA3 (1003) can decide (1007) to participate in the next EDCA+ competition.

[0152] Since STA4 (1004) has traffic with AC_VO, which has the same priority as LAC=AC_VO, it can randomly select an APV within the range of PVs (if provided). If the APV selected by STA4 (1004) is 4, it can determine (1008) that it will not participate in the next EDCA+ contention since it is greater than the provided PV threshold = 3.

[0153] At the end of the last frame transmission (1011) of the corresponding TXOP of STA1 (1001) in the previous TXOP (1010), the AP (1000) and STAs (1001, 1002, 1003, 1004) may perform CCA (clear channel assessment) to sense the wireless channel or carrier or medium for a predetermined time period in the EDCA contention period (1020). For example, STA1 (1001), STA2 (1002), and STA4 (1004) may perform sensing during AIFS (=SIFS+AIFSN*slot time), and AP (1000) and STA3 (1003) may perform sensing during a period shorter than the AIFS (e.g., DIFS).

[0154] If the sensing result of STA3 (1003) determines that the channel is idle, STA3 (1003) may transmit a DS or frame (1021). AP (1000), STA1 (1001), STA2 (1002), and STA4 (1004), which have not transmitted the above DS or frame, may determine that the channel state is “busy” and may not participate in the contention.

[0155] STA3 (1003) can generate (1022) an arbitrary backoff (BO) counter between a specific section (0 to 7). In this drawing, the case where the value of the BO counter of STA3 (1003) is '3' is illustrated as an example. STA3 (1003) can decrease the BO counter by 1 for every 1 slot time. Thereafter, when the value of the BO counter of STA3 (1003) reaches '0', STA3 (1003) can acquire a TXOP (1030) and transmit (1031) a PPDU. The PPDU transmission may include STA3 (1003) transmitting an uplink signal to AP (1000).

[0156] Figure 11 is a diagram illustrating a scenario in which an STA is not allowed to access a channel via EDCA+.

[0157] Referring to FIG. 11, one or more STAs (1101, 1102, 1103, 1104) may set up a link to a network and be associated with an AP (1100). Here, STA1 (1101) may be a conventional station or an STA with relatively low priority traffic, and STA2 (1102), STA3 (1103), and STA4 (1104) are stations that support EDCA+ or HiP EDCA, and STA2 (1102) may have AC_VI traffic, and STA3 (1103) and STA4 (1104) may each have AC_VO traffic.

[0158] AP (1100) may transmit (1105) a management frame to STAs (1101, 1102, 1103, 1104) within the network at a specific point in time. The management frame may be a beacon frame periodically broadcast by the AP, which may include one or more parameters for EDCA+ listed in the description of FIG. 9. In this drawing, it is assumed that AP (1100) transmits a beacon frame with the PV threshold value set to 0.

[0159] STA2 (1102), STA3 (1103), and STA4 (1104) supporting EDCA+ or HiP EDCA can determine whether they can participate in EDCA+ based on the parameter(s) included in the beacon frame. At this time, since the PV threshold value is set to 0, STA2 (1102), STA3 (1103), and STA4 (1104) can determine that contention-based channel access is not permitted.

[0160] At the end of the last frame transmission (1111) of the corresponding TXOP of STA1 (1101) in the previous TXOP (1110), the AP (1100) and STAs (1101, 1102, 1103, 1104) may perform CCA (clear channel assessment) to sense the wireless channel or carrier or medium for a predetermined time period in the EDCA contention period (1120). For example, STA1 (1101), STA2 (1102), STA3 (1103), and STA4 (1104) may perform sensing during AIFS (=SIFS+AIFSN*slot time), and the AP (1100) may perform sensing during a period shorter than the AIFS (e.g., DIFS).

[0161] If the sensing result of AP (1100) determines that the channel is idle, AP (1100) may transmit (1121) a DS or frame. At this time, the frame may be a control frame (e.g., a trigger frame). STA1 (1101), STA2 (1102), STA3 (1103), and STA4 (1104), which have not transmitted the DS or frame, may determine that the channel status is “busy” and may not participate in the contention.

[0162] AP (1100) may acquire TXOP (1130) and transmit PPDU (1131) at least after a minimum time interval for the next frame transmission. The PPDU transmission may include AP (1100) transmitting a downlink signal to STA3 (1103).

[0163] Figure 12 is a diagram illustrating a scenario where an AP and an STA with high priority traffic are allowed to access a channel via EDCA+, but contention is controlled by additional intervention from the AP.

[0164] Referring to FIG. 12, one or more STAs (1201, 1202, 1203, 1204) may set up a link to a network and be associated with an AP (1200). Here, STA1 (1201) may be a conventional station or an STA with relatively low priority traffic, and STA2 (1202), STA3 (1203), and STA4 (1204) are stations that support EDCA+ or HiP EDCA, and STA2 (1202) may have AC_VI traffic, and STA3 (1203) and STA4 (1204) may each have AC_VO traffic.

[0165] AP (1200) may transmit (1205) a management frame to STAs (1201, 1202, 1203, 1204) within the network at a specific point in time. The management frame may be a beacon frame periodically broadcast by the AP, which may include one or more parameters for EDCA+ listed in the description for FIG. 9. In this drawing, it is assumed that AP (1200) transmits a beacon frame including at least one of PV threshold value = 3, PV range = [0, 10], and LAC = AC_VO.

[0166] STA2 (1202), STA3 (1203), and STA4 (1204) supporting EDCA+ or HiP EDCA can determine whether they can participate in EDCA+ based on the parameter(s) included in the beacon frame.

[0167] STA2 (1202) can determine (1206) not to participate in EDCA+ because it has traffic of AC_VI, which is a lower priority than LAC=AC_VO.

[0168] Since STA3 (1203) has traffic with AC_VO priority, which is the same as LAC=AC_VO, it can randomly select an APV within the range of PVs (if provided). If the APV selected by STA3 (1203) is 2, it is less than the provided PV threshold value = 3, so STA3 (1203) can decide (1207) to participate in the next EDCA+ competition.

[0169] Since STA4 (1204) has traffic with AC_VO priority, which is the same as LAC=AC_VO, it can randomly select an APV within the range of PVs (if provided). If the APV selected by STA4 (1204) is 4, it can determine (1208) that it will not participate in the next EDCA+ contention since it is greater than the provided PV threshold value = 3.

[0170] At the end of the last frame transmission (1211) of the corresponding TXOP of STA1 (1201) in the previous TXOP (1210), the AP (1200) and STAs (1201, 1202, 1203, 1204) may perform CCA (clear channel assessment) to sense the wireless channel or carrier or medium for a predetermined time period in the EDCA contention period (1220). For example, STA1 (1201), STA2 (1202), and STA4 (1204) may perform sensing during AIFS (=SIFS+AIFSN*slot time), and STA3 (1203) may perform sensing during a period shorter than the AIFS (e.g., DIFS). At this time, if AP (1200) wants to additionally intervene and control contention, AP (1200) can perform sensing for a shorter period (e.g., PIFS) than the channel sensing period (e.g., DIFS) of STA3 (1203).

[0171] If the sensing result of AP (1200) determines that the channel is idle, AP (1200) may transmit (1221) a DS or frame. At this time, the frame may be a control frame (e.g., a trigger frame). STA1 (1201), STA2 (1202), STA3 (1203), and STA4 (1204), which have not transmitted the DS or frame, may determine that the channel status is “busy” and may not participate in the contention.

[0172] The above DS or frame may contain information that triggers transmission of STA3 (1203), and accordingly, STA3 (1203) may acquire TXOP (1230) and transmit PPDU (1231). The PPDU transmission may include STA3 (1203) transmitting an uplink signal to AP (1200).

[0173] Figure 13 is a diagram illustrating a scenario in which an STA with high priority traffic is allowed to access a contention-based channel through short-term control of an AP.

[0174] Referring to FIG. 13, one or more STAs (1301, 1302, 1303, 1304) may set up a link to a network and be associated with an AP (1300). Here, STA1 (1301) may be a conventional station or an STA with relatively low priority traffic, and STA2 (1302), STA3 (1303), and STA4 (1304) are stations that support EDCA+ or HiP EDCA, and STA2 (1302) may have AC_VI traffic, and STA3 (1303) and STA4 (1304) may each have AC_VO traffic.

[0175] The AP (1300) may transmit (1305) a management frame to STAs (1301, 1302, 1303, 1304) within the network at a specific point in time. The management frame may be a beacon frame periodically broadcast by the AP, which may include one or more parameters for EDCA+ listed in the description of FIG. 9. In this drawing, it is assumed that the AP (1300) transmits a beacon frame with the PV threshold set to 0.

[0176] STA2 (1302), STA3 (1303), and STA4 (1304) supporting EDCA+ or HiP EDCA can determine whether they can participate in EDCA+ based on the parameter(s) included in the beacon frame. At this time, since the PV threshold value is set to 0, STA2 (1302), STA3 (1303), and STA4 (1304) can determine that contention-based channel access is not permitted.

[0177] At the end of the last frame transmission (1311) of the corresponding TXOP of STA1 (1301) in the previous TXOP (1310), the AP (1300) and STAs (1301, 1302, 1303, 1304) may perform CCA (clear channel assessment) to sense the wireless channel or carrier or medium for a predetermined time period in the EDCA contention period (1320). For example, STA1 (1301), STA2 (1302), STA3 (1303), and STA4 (1304) may perform sensing during AIFS (=SIFS+AIFSN*slot time), and the AP (1300) may perform sensing during a period shorter than the AIFS (e.g., DIFS).

[0178] If the sensing result of the AP (1300) determines that the channel is idle, the AP (1300) may transmit (1321) a DS or frame to allow a short-term contention-based channel access of an STA with high priority traffic. At this time, the frame may be a control frame (e.g., a trigger frame) and may include at least one of the following parameters or a combination thereof.

[0179] - Backoff Counter Range: You can indicate the range (e.g., 0 to N) of the backoff counter used for contention-based channel access of STAs. STAs can arbitrarily select a backoff counter within the range.

[0180] - Traffic Type: The AC (access category), TID (traffic identifier), and / or TSID (traffic stream identifier) ​​that allow contention-based channel access can be indicated. An STA can participate in contention-based channel access if it has traffic with a priority higher than the indicated AC, TID, and / or TSID.

[0181] - Buffer Size: You can indicate the minimum buffer size (e.g., 1024 bytes) that allows contention-based channel access. For example, an STA can participate in a contention-based channel access if the size of the traffic it intends to transmit within the buffer is equal to or larger than the indicated buffer size.

[0182] - RU (resource unit) allocation information: RU, which is a frequency unit that is allocated to multiple STAs to enable simultaneous signal transmission and reception, can be indicated. At this time, multiple RA-RUs (random access RUs) can be provided.

[0183] In another embodiment, if the AP (1300) wants to perform the short-term control with priority among other APs, the AP (1300) may perform sensing for a shorter period (e.g., PIFS) than the DIFS, and if the sensing result determines that the channel is idle, the above-described DS or frame may be transmitted (1321).

[0184] For example, if the traffic type information provided as the DS or frame is set to 'AC_VI', STA2 (1302), STA3 (1303), and STA4 (1304) having traffic of the same or higher priority can each generate (1322, 1323, 1324) a random backoff (BO) counter within the backoff counter range. In this drawing, the case where the value of the BO counter of STA2 (1302) is '5', the value of the BO counter of STA3 (1303) is '2', and the value of the BO counter of STA4 (1304) is '7' is illustrated as an example. STA2 (1302), STA3 (1303), and STA4 (1304) can decrease the BO counter by 1 every 1 slot time. Afterwards, since the value of the BO counter of STA3 (1303) reaches '0' first, STA3 (1303) can acquire TXOP (1330) and transmit PPDU (1331).

[0185] Figure 14 is a flowchart illustrating the operation of STA.

[0186] Referring to FIG. 14, at step 1410, the STA may receive a management frame including a PV threshold value. For example, the management frame may be a beacon frame periodically broadcast by the AP, and may include one or more parameters listed in the description for FIG. 9.

[0187] In step 1420, the STA can determine whether contention-based channel access is permitted based on the PV threshold. For example, if the PV threshold is not 0, the STA's contention-based channel access may be permitted. Conversely, if the PV threshold is 0, the STA's contention-based channel access is not permitted, and only the AP can access the channel.

[0188] In step 1430, the STA may determine an APV within the PV range if the contention-based channel access is permitted. For example, the STA may determine an APV within an arbitrary interval or within the PV range provided by the AP via the management frame.

[0189] In step 1440, the STA may transmit a signal (e.g., a DS) or frame associated with contention-based channel access after channel sensing based on the PV threshold and the determined APV. For example, the STA may compare the APV with the PV threshold. If the APV is less than, equal to, or less than the PV threshold, the STA may transmit the DS or frame if the channel is idle as a result of performing a CCA after a DIFS.

[0190] Thereafter, the STA may obtain a TXOP according to one or a combination of the methods described with respect to FIGS. 9 to 13 described above, and transmit a PPDU in the obtained TXOP.

[0191] Figure 15 is a flowchart illustrating the operation of the AP.

[0192] Referring to FIG. 15, at step 1510, the AP may determine whether to allow contention-based channel access of the STA.

[0193] In step 1520, the AP may generate a PV threshold based on the above judgment result. For example, if the AP wishes to allow STAs to access a contention-based channel, the PV threshold may be set to a non-zero value. Conversely, if the AP does not wish to allow STAs to access a contention-based channel and wishes to allow only the AP to access the channel, the PV threshold may be set to 0.

[0194] In step 1530, the AP may transmit a management frame including the PV threshold value. The management frame may be a beacon frame periodically broadcast by the AP and may include one or more parameters listed in the description of FIG. 9.

[0195] In step 1540, if the STA's contention-based channel access is allowed, the AP may receive a signal (e.g., DS) or frame associated with the contention-based channel access after channel sensing. For example, the STA may determine an APV within an arbitrary interval or within a PV range provided by the AP through the management frame, and compare the APV with a PV threshold. If the APV is less than or equal to the PV threshold, the STA may transmit a DS or frame if the channel is idle as a result of performing a CCA after a DIFS, and the AP may receive it.

[0196] Thereafter, the AP may receive a PPDU in a TXOP acquired from the STA according to one or a combination of the methods described with respect to FIGS. 9 to 13 described above. Alternatively, the AP may perform sensing for a shorter period (e.g., PIFS) than the channel sensing period (e.g., DIFS) of the STA, and if the sensing result determines that the channel is idle, the AP may transmit (1221) a DS or frame to trigger transmission of a specific STA. Alternatively, even if the AP determines not to allow contention-based channel access of the STA in step 1510 as described with respect to FIG. 13, the AP may transmit a DS or frame to allow contention-based channel access of an STA with high priority traffic for a short period of time after the PIFS.

[0197] According to the above-described embodiment, the AP can control the channel access method of STAs within the network in relatively fine detail using the PV threshold. In the following embodiment, a method for controlling the activation / deactivation (or ON / OFF) of channel access in the EDCA+ (EDCA Plus) or HiP EDCA (High Priority EDCA) method based on the lowest access class (LAC) without using the PV threshold is described.

[0198] Figure 16 is a diagram illustrating a conceptual diagram of a method for controlling contention-based channel access based on LAC.

[0199] Referring to FIG. 16, at step 1600, the AP may transmit a management frame to STAs within the network. The management frame may be a beacon frame periodically broadcast by the AP. The AP may select the lowest AC (LAC) that allows channel access in the EDCA+ or HiP EDCA scheme and set the LAC value. The management frame may be transmitted including the selected LAC value.

[0200] If the LAC value is set to 0, it may mean that STAs are not allowed to access the channel using EDCA+ or HiP EDCA. On the other hand, if the LAC value is set to a non-zero value, it may mean that STAs are allowed to access the channel using EDCA+ or HiP EDCA.

[0201] More specifically, LAC=1 can indicate AC_VO as a LAC that allows channel access in the EDCA+ or HiP EDCA mode. In this case, only STA(s) that wish to transmit AC_VO traffic can perform channel access in the EDCA+ or HiP EDCA mode.

[0202] LAC=2 can indicate AC_VI as an LAC that allows channel access in the EDCA+ or HiP EDCA mode. In this case, only STA(s) that wish to transmit AC_VO traffic or STA(s) that wish to transmit AC_VI traffic can perform channel access in the EDCA+ or HiP EDCA mode.

[0203] LAC=3 can be marked as "reserved," indicating a reserved state for flexible design considering future system scalability. In this case, the specific behavior of each STA may vary depending on the implementation.

[0204] If the LAC value is set to a non-zero value, in step 1610, the STA can check whether the priority of the traffic to be transmitted is higher than (or higher than or equal to) the priority indicated by the LAC value.

[0205] At this time, if the priority of the traffic that the STA is trying to transmit is higher than (or equal to) the priority indicated by the LAC value, the STA can transmit a DS or frame after DIFS, and then, at step 1620, the STA can access the channel using the EDCA+ method or the HiP EDCA method.

[0206] Otherwise, if the priority of the traffic that the STA is trying to transmit is lower than or equal to (or lower than) the priority indicated by the LAC value, the STA may access the channel using the general EDCA method without transmitting a DS or frame after DIFS.

[0207] FIG. 17 is a diagram illustrating various examples of a method for controlling contention-based channel access based on LAC.

[0208] Referring to FIG. 17, one or more STAs (1701, 1702, 1703) may set up a link to a network and be associated with an AP (1700). Here, STA1 (1701) may be a conventional station or an STA with relatively low priority traffic, and STA2 (1702) and STA3 (1703) are stations that support EDCA+ or HiP EDCA, where STA2 (1702) may have AC_VI traffic and STA3 (1703) may have AC_VO traffic.

[0209] In Example 1 (1710), the AP (1700) may not allow channel access using the EDCA+ or HiP EDCA method. The AP (1700) may transmit a beacon frame (1711) including a LAC value set to 0. Since the LAC value is set to 0, this may mean that channel access using the EDCA+ or HiP EDCA method is not allowed for all STAs in the network. Accordingly, STA1 (1701), STA2 (1702), and STA3 (1703) cannot use the EDCA+ or HiP EDCA method regardless of the traffic priority or support of the corresponding function, and may perform channel access using the general EDCA method. That is, the AP (1700) may disable (or turn off) channel access using the EDCA+ or HiP EDCA method for all STAs in the network by setting the LAC value to 0.

[0210] In Example 2 (1720), the AP (1700) may allow channel access using the EDCA+ or HiP EDCA scheme for STA(s) with AC_VO traffic. The AP (1700) may transmit a beacon frame (1721) including a LAC value set to 1. Since the LAC value is set to 1, channel access using the EDCA+ or HiP EDCA scheme may be allowed only for STA(s) with AC_VO traffic. STA1 (1701) and STA2 (1702) may not be able to use the EDCA+ or HiP EDCA scheme because they do not support the function or have traffic with a lower priority than the LAC value. Therefore, STA1 (1701) and STA2 (1702) may perform channel access using the general EDCA scheme. On the other hand, STA3 (1703) can perform EDCA+ or HiP EDCA method channel access (1722) because it has AC_VO traffic with a higher priority than the LAC value. That is, the AP (1700) can activate (or turn on) EDCA+ or HiP EDCA method channel access by setting the LAC value to 1, but can give priority only to AC_VO traffic with high delay sensitivity.

[0211] In Example 3 (1730), AP (1700) may allow channel access using EDCA+ or HiP EDCA for STA(s) having AC_VO traffic and AC_VI traffic. AP (1700) may transmit a beacon frame (1731) including a LAC value set to 2. Since the LAC value is set to 2, channel access using EDCA+ or HiP EDCA may be allowed only for STA(s) having AC_VI and AC_VO traffic. STA1 (1701) may not be able to use EDCA+ or HiP EDCA because it does not support the function or has traffic with a lower priority than the LAC value. Therefore, STA1 (1701) may perform channel access using the general EDCA method. On the other hand, STA2 (1702) and STA3 (1703) have AC_VI and AC_VO traffic, respectively, which may correspond to the same or higher priority as the configured LAC value (2). Therefore, STA2 (1702) can perform channel access (1732) in the EDCA+ or HiP EDCA manner based on the AC_VI traffic. In addition, STA3 (1703) can perform channel access (1733) in the EDCA+ or HiP EDCA manner based on the AC_VO traffic. That is, the AP (1700) can activate (or turn on) channel access in the EDCA+ or HiP EDCA manner by setting the LAC value to 2, but can give priority to AC_VI traffic as well as AC_VO traffic.

[0212] Figure 18 is a diagram illustrating a scenario for controlling contention-based channel access based on LAC and time offset.

[0213] Referring to FIG. 18, one or more STAs (1801, 1802, 1803) may set up a link to a network and be associated with an AP (1800). Here, STA1 (1801) may be a conventional station or an STA with relatively low priority traffic, and STA2 (1802) and STA3 (1803) are stations that support EDCA+ or HiP EDCA, where STA2 (1802) may have AC_VI traffic and STA3 (1803) may have AC_VO traffic.

[0214] The AP (1800) may transmit a first beacon frame (1805) including a LAC value set to 0. Since the LAC value is set to 0, this may mean that channel access in the EDCA+ or HiP EDCA manner is not permitted for all STAs in the network. Accordingly, STA1 (1801), STA2 (1802), and STA3 (1803) cannot use the EDCA+ or HiP EDCA manner regardless of the traffic priority or support of the corresponding function, and may perform channel access through the general EDCA manner. That is, the AP (1800) may disable (or turn off) channel access in the EDCA+ or HiP EDCA manner for all STAs in the network by setting the LAC value to 0.

[0215] Thereafter, the AP (1800) may transmit a second beacon frame (1810) including a LAC value set to 1. Since the LAC value is set to 1, channel access in the EDCA+ or HiP EDCA manner may be permitted only for STA(s) with AC_VO traffic. Here, the second beacon frame (1810) may further include information about a time offset, and although the drawing illustrates a case where the time offset value is set to 30 ms as an example, the present invention is not limited thereto. In addition, the unit of the time offset may be set to an absolute time unit other than ms or may be set based on the Target Beacon Transmission Time (TBTT).

[0216] The above time offset may indicate the point in time at which the LAC value included in the second beacon frame (1810) is applied. Accordingly, STA1 (1801), STA2 (1802), and STA3 (1803) can still perform channel access through the general EDCA method according to the LAC value (0) set through the first beacon frame (1805).

[0217] After the time offset (30 ms) has elapsed from the time the second beacon frame (1810) is received, only STAs with a specific traffic priority among the STAs can perform channel access via the EDCA+ or HiP EDCA method according to the LAC value (1) set via the second beacon frame (1810). Since the LAC value is set to 1, channel access via the EDCA+ or HiP EDCA method may be permitted only for STA(s) with AC_VO traffic. STA1 (1801) and STA2 (1802) may not be able to use the EDCA+ or HiP EDCA method because they do not support the function or have traffic with a lower priority than the LAC value. Therefore, STA1 (1801) and STA2 (1802) may continue to perform channel access via the general EDCA method. On the other hand, STA3 (1803) has AC_VO traffic with a higher priority than the LAC value, so it can perform channel access (1815) in the EDCA+ or HiP EDCA manner.

[0218] In this way, the AP (1800) can dynamically control channel access of STAs by combining time offset and LAC values, and by preferentially allocating network resources to STAs with high priority traffic after a certain point in time, it can ensure efficient resource management of the network and quality of traffic with high delay sensitivity.

[0219] The methods according to the embodiments described in the claims or specification of the present disclosure may be implemented in the form of hardware, software, or a combination of hardware and software.

[0220] When implemented in software, a computer-readable storage medium storing one or more programs (software modules) may be provided. The one or more programs stored in the computer-readable storage medium are configured for execution by one or more processors within an electronic device. The one or more programs include instructions that cause the electronic device to execute methods according to embodiments described in the claims or specification of the present disclosure.

[0221] These programs (software modules, software) may be stored in random access memory, non-volatile memory including flash memory, read only memory (ROM), electrically erasable programmable read only memory (EEPROM), magnetic disc storage device, compact disc ROM (CD-ROM), digital versatile discs (DVDs) or other forms of optical storage device, magnetic cassette. Or, they may be stored in a memory configured as a combination of some or all of these. In addition, each configuration memory may be included in multiple numbers.

[0222] Additionally, the program may be stored on an attachable storage device that is accessible via a communication network, such as the Internet, an intranet, a local area network (LAN), a wide local area network (WLAN), a storage area network (SAN), or a combination thereof. Such a storage device may be connected to a device implementing an embodiment of the present disclosure via an external port. Additionally, a separate storage device on the communication network may be connected to a device implementing an embodiment of the present disclosure.

[0223] In the specific embodiments of the present disclosure described above, components included in one embodiment are expressed singularly or plurally, depending on the specific embodiment presented. However, the singular or plural expressions are selected to suit the presented situation for convenience of explanation, and the present disclosure is not limited to singular or plural components. Components expressed in plural may be composed of singular elements, or components expressed in singular may be composed of plural elements.

[0224] The above flowchart illustrates exemplary methods that can be implemented according to the principles of the present disclosure, and various modifications may be made to the methods depicted in the flowcharts herein. For example, although depicted as a series of steps, various steps in each drawing may overlap, occur in parallel, occur in different orders, or occur multiple times. In other instances, steps may be omitted or replaced with other steps. The values ​​described above are merely examples, and it is entirely possible for other values ​​to be applied.

[0225] Meanwhile, the embodiments of the present disclosure disclosed in this specification and drawings are merely specific examples to easily explain the technical content of the present disclosure and help understand the present disclosure, and are not intended to limit the scope of the present disclosure. In other words, it will be apparent to those skilled in the art to which the present disclosure pertains that other modifications based on the technical idea of ​​the present disclosure are possible. In addition, the above-described embodiments can be combined and operated as needed. For example, parts of one embodiment of the present disclosure and parts of another embodiment can be combined to operate an AP and a STA.

[0226] Additionally, the order of description in the drawings illustrating the method of the present invention does not necessarily correspond to the order of execution, and the order of precedence may be changed or executed in parallel. Alternatively, the drawings illustrating the method of the present invention may omit some components and include only some components, as long as it does not harm the essence of the present invention.

Claims

1. A method performed by a STA (station) of a wireless LAN (local access network) system, A step of receiving a management frame including a PV (priority value) threshold value; A step of identifying whether contention-based channel access is allowed based on the above PV threshold; If the above contention-based channel access is allowed, a step of determining APV (access PV) within the PV range; and A method comprising the step of transmitting a signal or frame associated with the contention-based channel access after channel sensing based on the PV threshold and the APV.

2. In paragraph 1, A method characterized in that when the PV threshold value is not 0, the contention-based channel access is allowed, and when the PV threshold value is 0, the contention-based channel access is not allowed.

3. In paragraph 1, The step of transmitting the above signal or frame is: If the APV is equal to or less than the PV threshold, a step of performing a clear channel assessment (CCA) during a DCF (distributed coordination function) IFS (inter frame space) after the last frame of the previous TXOP (transmission opportunity); A method characterized by comprising a step of transmitting the signal or frame when the channel is determined to be idle based on the CCA.

4. In paragraph 1, A step of selecting a backoff counter based on transmitting the above signal or frame; When the above backoff counter reaches 0, a step of acquiring a TXOP (transmission opportunity); and Further comprising a step of transmitting a PPDU (physical layer protocol data unit) based on the above TXOP, A method characterized in that the management frame further includes at least one of information about the PV range, information about a lowest access category (LAC) in which the contention-based channel access is allowed, information about the number of retransmissions in which the contention-based channel access is allowed, or information about the size of a backoff window used for the contention-based channel access.

5. In a method performed by an AP (access point) of a wireless LAN (local access network) system, A step for determining whether to allow contention-based channel access of STA (station); A step of generating a PV (priority value) threshold value based on the above judgment result; a step of transmitting a management frame including the PV threshold value; and A method comprising the step of receiving a signal or frame associated with the contention-based channel access, if the contention-based channel access is allowed.

6. In paragraph 5, A method characterized in that when the PV threshold value is not 0, the contention-based channel access is allowed, and when the PV threshold value is 0, the contention-based channel access is not allowed.

7. In paragraph 5, A method characterized in that the management frame further includes at least one of information about the PV range or information about the lowest access category (LAC) in which the contention-based channel access is allowed.

8. In paragraph 5, A method characterized in that the management frame further includes at least one of information about the number of retransmissions allowed for the contention-based channel access or information about the size of a backoff window used for the contention-based channel access.

9. In the STA (station) of a wireless LAN (local access network) system, At least one transceiver; At least one processor communicatively connected to said at least one transceiver; and Communicably connected to at least one processor, and executable individually or in any combination of said at least one processor, such that said STA A management frame including a PV (priority value) threshold value is received through the transceiver, Based on the above PV threshold, identify whether contention-based channel access is allowed, If the above contention-based channel access is allowed, the APV (access PV) is determined within the PV range, Based on the PV threshold and the APV, a signal or frame associated with the contention-based channel access is transmitted through the transceiver after channel sensing. Memory that stores commands to do something; STA including .

10. In paragraph 9, An STA characterized in that when the PV threshold value is not 0, the contention-based channel access is allowed, and when the PV threshold value is 0, the contention-based channel access is not allowed.

11. In paragraph 9, Instructions executable by at least one processor individually or in any combination thereof, wherein the STA If the above APV is equal to or less than the above PV threshold, a CCA (clear channel assessment) is performed during the DCF (distributed coordination function) IFS (inter frame space) after the last frame of the previous TXOP (transmission opportunity), If the channel is determined to be idle based on the above CCA, the signal or frame is transmitted through the transceiver. STA characterized by having the following properties:

12. In paragraph 9, The above control unit, Based on the transmission of the above signal or frame, a backoff counter is selected, When the above backoff counter reaches 0, a TXOP (transmission opportunity) is acquired. It is configured to transmit a PPDU (physical layer protocol data unit) through the transceiver based on the above TXOP, An STA characterized in that the management frame further includes at least one of information about the PV range, information about a lowest access category (LAC) in which the contention-based channel access is allowed, information about the number of retransmissions in which the contention-based channel access is allowed, or information about the size of a backoff window used for the contention-based channel access.

13. In the AP (access point) of a wireless LAN (local access network) system, At least one transceiver; At least one processor communicatively connected to said at least one transceiver; and Communicably connected to at least one processor, and executable individually or in any combination of said at least one processor, so that said AP Determine whether to allow contention-based channel access for STA (station), Based on the above judgment results, a PV (priority value) threshold is generated, Transmitting a management frame including the above PV threshold value through the transceiver, If the above contention-based channel access is allowed, a signal or frame associated with the contention-based channel access is received through the transceiver. Memory that stores commands to do something; AP including .

14. In paragraph 13, An AP characterized in that when the PV threshold value is not 0, the contention-based channel access is allowed, and when the PV threshold value is 0, the contention-based channel access is not allowed.

15. In paragraph 13, An AP characterized in that the management frame further includes at least one of information about the PV range, information about a lowest access category (LAC) in which the contention-based channel access is allowed, information about the number of retransmissions in which the contention-based channel access is allowed, or information about the size of a backoff window used for the contention-based channel access.

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