Communication method and apparatus using preemption in wireless local area network system

Abstract

The purpose of the present invention is to perform communication by using preemption in a wireless local area network system. A method for operating a station (STA) comprises the steps of: acquiring at least some parameters of a first frame based on the first frame; acquiring a preemption indicator from a second frame including the preemption indicator; transmitting a third frame notifying a preemption operation according to the preemption indicator; receiving a fourth frame indicating resources allocated for the preemption operation; and transmitting the preemption data based on the resource, wherein the parameter of the first frame and the parameter of the third frame have the same value.

Description

TECHNICAL FIELD

[0001] The present application relates to a wireless local area network system, and more particularly, to a communication method and apparatus using preemption in a wireless local area network system. BACKGROUND

[0002] Recently, as mobile devices are popularized, a wireless local area network technology capable of providing a fast wireless communication service to the mobile devices is attracting attention. The wireless local area network technology can be a technology for supporting a mobile device (e.g., a smart phone, a smart tablet, a laptop computer, a portable multimedia player, an embedded device, etc.) to access the Internet in a wireless manner based on a wireless communication technology.

[0003] As applications requiring higher throughput and applications requiring real-time transmission are emerging, an IEEE 802.11be standard as an Extreme High Throughput (EHT) wireless local area network technology is being developed. The IEEE 802.11be standard can target supporting a high throughput of 30 Gbps. The IEEE 802.11be standard can support a technology for reducing transmission latency. In addition, the IEEE 802.11be standard can support a further extended frequency bandwidth (e.g., a 320 MHz bandwidth), multi-link transmission and aggregation operation including operation using multiple frequency bands (multi-band), multi-access point (AP) transmission operation, and / or an efficient retransmission operation (e.g., a Hybrid Automatic Repeat Request (HARQ) operation).

[0004] On the other hand, the technology described in the background section is written in order to improve the understanding of the background of the present application, and can include what is not known to those of ordinary skill in the art to which the present application pertains. SUMMARY

[0005] TECHNICAL PROBLEM The present application provides a method and apparatus for performing communication using preemption in a wireless local area network (WLAN) system.

[0006] The present application provides a method and apparatus for exchanging data during a preemption operation within a transmit opportunity (TXOP) in a WLAN system.

[0007] The present application provides a method and apparatus for performing preemption between inter-frame intervals transmitted by other terminals in a WLAN system.

[0008] The present application provides a method and apparatus for controlling a preemption operation in a wireless LAN system.

[0009] The present application provides a method and apparatus for controlling an interframe space during a preemption operation in a wireless LAN system.

[0010] The technical objects to be achieved in the present application are not limited to the above described, and other technical objects not mentioned herein can be considered by those skilled in the art of the technical field to which the present application pertains from the embodiments of the present application to be described below.

[0011] Technical Solution According to an embodiment of the present application, a method of operating a STA (Station) in a wireless LAN system can include acquiring at least some parameters of a first frame based on the first frame; acquiring a preemption indicator from a second frame including the preemption indicator; transmitting a third frame indicating a preemption operation based on the preemption indicator; receiving a fourth frame indicating resources allocated for the preemption operation; and transmitting preemption data based on the resources. The parameters of the first frame and the third frame have the same value.

[0012] According to an embodiment of the present application, a method of operating an AP (Access Point) in a wireless LAN system can include transmitting a first frame; transmitting a second frame including a preemption indicator; receiving a third frame indicating a preemption operation based on the preemption indicator; transmitting a fourth frame indicating resources allocated for the preemption operation; and receiving preemption data based on the resources. The first frame and the third frame include parameters having the same value.

[0013] According to an embodiment of the present application, a Station (STA) in a wireless LAN system can include a transceiver and a processor connected to the transceiver. The processor can acquire at least some parameters of a first frame based on the first frame; acquire a preemption indicator from a second frame including the preemption indicator; transmit a third frame indicating a preemption operation based on the preemption indicator; receive a fourth frame indicating resources allocated for the preemption operation; and transmit preemption data based on the resources. The parameters of the first frame and the third frame have the same value.

[0014] According to an embodiment of the present application, an Access Point (AP) in a wireless LAN system can include a transceiver and a processor connected to the transceiver. The processor can transmit a first frame; transmit a second frame including a preemption indicator; receive a third frame indicating a preemption operation based on the preemption indicator; transmit a fourth frame indicating resources allocated for the preemption operation; and receive preemption data based on the resources. The first frame and the third frame include parameters having the same value.

[0015] Advantageous Effects According to the present application, a preemption operation can be performed.

[0016] According to the present application, an interframe space for preemption operation can be controlled.

[0017] According to the present application, a preemption request frame can be transmitted based on a Multi User-Request To Send (MU-RTS) trigger frame for setting a transmission opportunity (TXOP).

[0018] According to the present application, a plurality of wireless LAN terminals can simultaneously transmit a preemption request frame.

[0019] According to the present application, resources for preemption operation can be allocated to a plurality of wireless LAN terminals.

[0020] The effects obtained in the present application are not limited to the above-mentioned effects, and other effects which are not mentioned above can be clearly deduced and understood from the following description of the embodiments of the present application by those skilled in the art of the technical field to which the present application pertains. That is, those skilled in the art can also deduce unintended effects in implementing the configurations described in the present application from the embodiments of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 is a block diagram illustrating a first embodiment of a communication node constituting a WLAN system.

[0022] Figure 2 is a flowchart illustrating an embodiment of a negotiation procedure for multi-link operation in a wireless LAN system.

[0023] Figure 3 A first embodiment of a communication method using preemption in a wireless LAN system is illustrated.

[0024] Figure 4 A second embodiment of a communication method using preemption in a wireless LAN system is illustrated.

[0025] Figure 5a A third embodiment of a communication method using preemption in a wireless LAN system is illustrated.

[0026] Figure 5b A third embodiment of a communication method using preemption in a wireless LAN system is illustrated.

[0027] Figure 6a A fourth embodiment of a communication method using preemption in a wireless LAN system is illustrated.

[0028] Figure 6b A fourth embodiment of a communication method using preemption in a wireless LAN system is illustrated.

[0029] Figure 6cA fifth embodiment of a communication method using preemption in a wireless local area network system is shown.

[0030] Figure 6d A fifth embodiment of a communication method using preemption in a wireless local area network system is shown.

[0031] Figure 7a A sixth embodiment of a communication method using preemption in a wireless local area network system is shown.

[0032] Figure 7b A sixth embodiment of a communication method using preemption in a wireless local area network system is shown.

[0033] Figure 8 A seventh embodiment of a communication method using preemption in a wireless local area network system is shown.

[0034] Figure 9a A first embodiment of a frequency unit (tone) mapping structure and allocation method for NDP feedback report polling (NFRP) in a wireless local area network system is shown.

[0035] Figure 9b A second embodiment of a frequency unit mapping structure and allocation method for NFRP in a wireless local area network system is shown.

[0036] Figure 9c A third embodiment of a frequency unit mapping structure and allocation method for NFRP in a wireless local area network system is shown.

[0037] Figure 9d A fourth embodiment of a frequency unit mapping structure and allocation method for NFRP in a wireless local area network system is shown.

[0038] Figure 10 A flowchart of a process for an access point (AP) to perform a preemption operation according to one embodiment of the present application is shown.

[0039] Figure 11 A flowchart of a process for a station (STA) to perform a preemption operation according to one embodiment of the present application is shown. DETAILED DESCRIPTION

[0040] The present application can have various modifications and embodiments, and specific embodiments are shown in the drawings and are described in detail in the detailed description. However, this is not intended to limit the present application to specific embodiments, but should be understood to include all modifications, equivalents, or alternatives included in the spirit and technical scope of the present application.

[0041] The terms first, second, etc. can be used to describe various components, but the components should not be limited by these terms. The terms are only used to distinguish one component from another. For example, a first component could be termed a second component, and, similarly, a second component could be termed a first component, without departing from the scope of the present application. The terms and / or a combination of multiple related terms can be included in the description.

[0042] When it is said that a component is "coupled to" or "connected to" another component, it should be understood that the component is directly connected to the other component or connected to the other component through any other components in between. On the other hand, when it is said that a component is "directly connected to" or "directly coupled to" another component, it should be understood that there are no other components between the components.

[0043] The terms used in the present application are only used to describe specific embodiments, and are not intended to limit the present application. The singular expression includes the plural expression, unless the context clearly dictates otherwise. In the present application, terms such as "include" or "have" are intended to indicate that there is existence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, but it should be understood that the possibility of existence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof is not precluded.

[0044] Unless otherwise defined, all terms (including technical terms or scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application pertains. Terms defined in commonly used dictionaries should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0045] Hereinafter, preferred embodiments of the present application will be described in greater detail with reference to the accompanying drawings. In order to facilitate overall understanding of the present application when describing the present application, the same reference numerals are used throughout the drawings for the same components and repetitive description of the same components is omitted.

[0046] Hereinafter, a wireless communication system to which embodiments of the present application are applied will be described. The wireless communication system to which embodiments of the present application are applied is not limited to the following description and can be applied to various wireless communication systems. The wireless communication system can be referred to as a "wireless communication network."

[0047] Figure 1 A block diagram of a communication node in a wireless local area network system is shown.

[0048] Reference Figure 1Communication node 100 can be an access point (AP), a station (STA), an AP multi-link device (MLD), or a non-AP MLD. STAs can be non-AP STAs. The operating channel width supported by the AP can be 20 MHz, 80 MHz, or 160 MHz. The operating channel width supported by the STA can be 20 MHz or 80 MHz.

[0049] Communication node 100 may include at least one processor 110, memory 120, and at least one transmitting / receiving device 130 connected to a network and performing communication. Transmitting / receiving device 130 may also be referred to as a transceiver, radio frequency (RF) unit, or RF module. Additionally, communication node 100 may further include an input interface device 140, an output interface device 150, and a storage device 160. Components included in communication node 100 can be connected via bus 170 and perform communication between them.

[0050] However, each component included in communication node 100 may be connected not via common bus 170, but via a separate interface or separate bus around processor 110. For example, processor 110 may be connected via a dedicated interface to at least one of memory 120, transmitting / receiving device 130, input interface device 140, output interface device 150, and storage device 160.

[0051] Processor 110 can execute program instructions stored in at least one of memory 120 and storage device 160. Processor 110 can be a central processing unit (CPU), graphics processing unit (GPU), or dedicated processor that performs methods according to embodiments of the present invention. Memory 120 and storage device 160 can each be configured as at least one volatile storage medium and at least one non-volatile storage medium. For example, memory 120 can be configured as at least one read-only memory (ROM) and random access memory (RAM).

[0052] Figure 2 This is a flowchart illustrating an implementation scheme for a negotiation process used for multi-link operation in a wireless local area network system.

[0053] refer to Figure 2The connection process between a station (STA) and an access point (AP) in the basic service set (BSS) can include access point detection steps, authentication steps between the station and the detected access point, and association steps between the station and the authenticated access point.

[0054] During the detection step, a station can detect one or more access points using either a passive scanning method or an active scanning method. When using a passive scanning method, the station can detect one or more access points by listening to beacon frames sent by one or more access points. When using an active scanning method, the station can detect one or more access points by sending a probe request frame and receiving probe response frames (responses to the probe request frames) from one or more access points.

[0055] If one or more access points are detected, the station can perform authentication steps with the detected access points. In this case, the station can perform authentication steps with multiple access points. Authentication algorithms according to the IEEE 802.11 standard can be divided into open system algorithms that exchange two authentication frames and shared key algorithms that exchange four authentication frames.

[0056] The station can send authentication request frames based on the authentication algorithm according to the IEEE 802.11 standard, and complete authentication with the access point by receiving authentication response frames (which are responses to the authentication request frames) from the access point.

[0057] Once authentication with an access point is complete, the station can perform the association step with that access point. In this case, the station can select one of the access points with which it has already completed the authentication step and perform the association step with the selected access point. That is, the station can send an association request frame to the selected access point and complete the association with the selected access point by receiving an association response frame from the selected access point (which is a response to the association request frame).

[0058] On the other hand, multi-link operation can be supported in a wireless LAN system. A Multi-Link Detection Element (MLD) can include one or more STAs associated with it. An MLD can be a logical entity. MLDs can be categorized as AP MLDs and non-AP MLDs. Each STA associated with an AP MLD can be an AP, and each STA associated with a non-AP MLD can be a non-AP STA. To configure multiple links, multi-link discovery procedures, multi-link establishment procedures, etc., can be performed. The multi-link discovery procedure can be performed during the probe step between the station and the access point. In this case, the multi-link information element (MLIE) can be included in beacon frames, probe request frames, and / or probe response frames.

[0059] For example, to perform multi-link operation, during the probing step, information indicating whether multi-link operation is available and information about available links can be exchanged between the access point (e.g., an AP associated with an MLD) and the station (e.g., a non-AP STA associated with an MLD). During the negotiation process for multi-link operation (e.g., a multi-link establishment process), the access point and / or station can send information about the links to be used for multi-link operation. The negotiation process for multi-link operation can be performed during the association process between the station and the access point (e.g., an association step), and the information elements required for multi-link operation can be set or changed via action frames during the negotiation process.

[0060] Furthermore, during the connection process between the station and the access point (e.g., the association step), the available links of the access point can be configured, and an identifier (ID) can be assigned to each link. Subsequently, during the negotiation and / or change process for multi-link operation, information indicating whether each link is active can be sent, and this information can be represented using the link ID.

[0061] Information indicating whether multi-link operation (STR) is available can be sent and received during the exchange of performance information elements (e.g., Extremely High Throughput (EHT) performance information elements) between the station and the access point. Performance information elements may include information about supported frequency bands, information about supported links (e.g., the ID and / or number of supported links), and information about links capable of STR operation (e.g., link frequency band information, link spacing information), etc. Furthermore, performance information elements may include information specifically indicating which links are capable of STR operation.

[0062] Hereinafter, embodiments of a communication method utilizing preemption according to an embodiment of the present invention will be described with reference to the accompanying drawings. The communication method utilizing preemption includes a method of allocating resources using preemption and transmitting data using the allocated resources. The communication method utilizing preemption may be referred to as a preemption operation, preemption process, preemption procedure, preemption method, or priority transmission. The lengths of the frames and time intervals shown in the drawings are exemplary, and the present invention includes embodiments in which the included frames and time intervals have lengths different from those shown in the drawings.

[0063] Figure 3 A first implementation of a communication method utilizing preemption in a wireless local area network system is shown.

[0064] refer to Figure 3 AP 1101, along with STA 1103, STA 2105, and STA 3107 connected to AP 1101, are operational. AP 1101 can perform an EDCA backoff operation to acquire a TXOP. Within the TXOP acquired by AP 1101, AP 1101 can transmit at least one frame (e.g., PPDU (Physical Layer Protocol Data Unit), MPDU (Media Access Control Layer Protocol Data Unit), A-MPDU (Aggregated MPDU)). The PPDU transmitted by AP 1101 may include one or more A-MPDUs or MPDUs.

[0065] AP 1 101 can send an initial frame 300 of the TXOP. Initial frame 300 can be a MU-RTS frame. If initial frame 300 is a MU-RTS frame, the AID in the user information field of the MU-RTS frame can indicate STA 1 103. STA 1 103 can refer to the parameters of the initially sent MU-RTS frame 300 (e.g., the channel for sending the CTS frame, resource element) to send a CTS frame after a certain period of time (e.g., PIFS, SIFS time, or XIFS time used for preemption operations) starting from the end time of the transmission of the MU-RTS frame 300 sent by AP 1 101.

[0066] AP 1 101 may send DL PPDU 310 to STA 1 103 after a certain period of time following the receipt of a CTS frame (e.g., PIFS, SIFS time, or XIFS time for preemption operations).

[0067] The DL PPDU 310 transmitted from AP 1 101 to STA 1 103 includes a preemption indicator (e.g., bits included in the PHY preamble, bits included in the MAC header, subfields, information elements, or indicator bits, etc.). The preemption indicator can be included in various forms in the frame 310 transmitted from AP 1 101 to STA 1 103. The preemption indicator can indicate whether preemption is possible for a certain period of time (e.g., PIFS, SIFS, or XIFS time used for preemption operations) starting from the end time of transmission of the DL PPDU 310. When the preemption indicator indicates that preemption is possible, at the end of transmission of the PPDU 310 including the preemption indicator, one or more STAs (e.g., STA 2 105 and STA 3 107) that need to perform the preemption operation listen to the channel for the XIFS time or a period shorter than the XIFS time used for preemption operations. One or more STAs may send a PR (preemption request) frame (e.g., S-CTS (synchronization CTS)) 320 to AP 1 101 during the XIFS time period to notify that there are LL packets to be sent. The S-CTS frame 320 may be a CTS frame sent by one or more STAs.

[0068] STA 2 105 and STA 3 107 can refer to the parameters of the initially transmitted MU-RTS frame 300 (e.g., the channel through which the CTS frame is transmitted) to simultaneously transmit PR frame 320 after a time shorter than the XIFS time used for preemption operations (e.g., SIFS time) from the end time of the transmission of DL PPDU 310 transmitted from AP 1 101, so as to transmit LL packets generated during the transmission period of DL PPDU 310 of AP 1 101 to AP 1 101. The SCRAMBLER_INITIAL_VALUE of the TXVECTOR parameter present in the PHY preamble of S-CTS frame 320 is set to be the same as the SCRAMBLER_INITIAL_VALUE of the RXVECTOR parameter present in MU-RTS frame 300. That is, the S-CTS frame is configured identically in all STAs based on the SCRAMBLER_INITIAL_VALUE value of the RXVECTOR parameter present in MU-RTS frame 300. Therefore, S-CTS frames will not conflict with each other. If AP 1 101 receives an S-CTS as PR frame 320, it can stop sending DL PPDUs waiting to be sent in AP 1 101 until the preemption sequence ends. Alternatively, AP 1 101 can send DL PPDUs even if it receives PR frame 300, and can attempt to execute the preemption sequence after sending the DL PPDU.

[0069] The preemption sequence can be executed as follows. AP 1 101 can send trigger frame 330 after receiving PR frame 320 for a certain period of time (e.g., XIFS time, PIFS time, SIFS time for preemption). Trigger frame 330 can be a frame for uplink OFDMA random access (UORA) resource allocation. For example, trigger frame 330 can be a frame for allocating uplink resources to STA 2 105 and STA 3 107, which sent PR frame 320. Referring to the information included in the common information field and user information field of trigger frame 330 (e.g., RA-RU (Random Access Resource Element) information included in the user information field), uplink resources can be allocated to STA 2 105 and STA 3 107. STA 2 105 and STA 3 107 can send uplink frame 340 to each OFDMA subchannel (e.g., resource element) after receiving trigger frame 330 for a certain period of time (e.g., SIFS time). AP 1 101 can receive uplink frame 340 from STA 2 105 and STA 3 107, and send response frames (e.g., BA frames) to STA 2 105 and STA 3 107.

[0070] Figure 4 A second implementation scheme for a communication method utilizing preemption in a wireless local area network system is shown.

[0071] refer to Figure 4 AP 1101, along with STA 1103, STA 2105, and STA 3107 connected to AP 1101, are operational. AP 1101 can perform an EDCA backoff operation to acquire a TXOP. Within the TXOP acquired by AP 1101, AP 1101 can transmit one or more frames (e.g., PPDU (Physical Layer Protocol Data Unit), MPDU (Media Access Control Layer Protocol Data Unit), A-MPDU (Aggregated MPDU)). The PPDU transmitted by AP 1101 may include one or more A-MPDUs or MPDUs.

[0072] AP 1 101 can send the first frame 400 of the TXOP. The first frame 400 of the TXOP can be an RTS frame. STA 1 103 can send a CTS frame after a certain period of time (e.g., PIFS, SIFS, or XIFS for preemption operations) starting from the end time of the transmission of the RTS frame 400 sent by AP 1 101.

[0073] After receiving a CTS frame, AP 1 101 may send DL PPDU 410 to STA 1 103 after a certain time period (e.g., PIFS, SIFS, or XIFS for preemption operations). The DLPPDU 410 sent from AP 1 101 to STA 1 103 includes preemption indicators (e.g., bits included in the PHY preamble, bits included in the MAC header, subfields, information elements, or indicator bits, etc.). The preemption indicators may be included in various forms in the frame 410 sent from AP 1 101 to STA 1 103. DL PPDU 410 may include an A-MPDU, and the A-MPDU may include a MU-RTS frame sent together as an A-MPDU. The AID of the user information field of the MU-RTS frame sent together as an A-MPDU in DL PPDU 410 may indicate broadcast (e.g., 0 or 2045). Alternatively, the AID in the User Information field of the MU-RTS frame can indicate STA 2105 or / and STA 3 107. The DL PPDU 410 and the MU-RTS frame for AP 1 101 can be transmitted separately. For example, the MU-RTS frame can be transmitted separately after a certain period of time (e.g., SIFS) following the transmission of the DL PPDU 410 for AP 1 101.

[0074] A preemption indicator can indicate whether preemption is permissible during a certain period of time (e.g., PIFS, SIFS, or XIFS for preemption operation) starting from the end time of transmission of DL PPDU 410. If the preemption indicator indicates that preemption is permissible, STA 2 105 and STA 3 107 can simultaneously transmit PR frames (e.g., S-CTS frames) 420 after a time shorter than the XIFS for preemption operation (e.g., SIFS) starting from the end time of transmission of DL PPDU 410 sent by AP 1 101, by referring to the parameters of the MU-RTS frame (e.g., the channel for transmitting CTS frames) sent together in the form of A-MPDU, to send LL packets generated during the transmission period of DL PPDU 410 of AP 1 101 to AP 1 101. The SCRAMBLER_INITIAL_VALUE of the TXVECTOR parameter in the PHY preamble of S-CTS frame 420 is set to be the same as the SCRAMBLER_INITIAL_VALUE of the RXVECTOR parameter in the MU-RTS frame (which is transmitted together with or separately as an A-MPDU). That is, the S-CTS frame is configured identically in all STAs based on the SCRAMBLER_INITIAL_VALUE value of the RXVECTOR parameter in MU-RTS frame 300. Therefore, S-CTS frames will not conflict with each other. When AP 1 101 receives the S-CTS as PR frame 420, it can stop transmitting DLPPDUs waiting to be transmitted in AP 1 101 until the preemption sequence ends. Alternatively, AP 1 101 can transmit DLPPDUs even after receiving PR frame 420, and may need to execute a preemption sequence after transmitting the DLPPDU.

[0075] The preemption sequence can be executed as follows. AP 1 101 can send trigger frame 430 after a certain time period (e.g., XIFS time, PIFS time, SIFS time for preemption) following the receipt of a PR frame (e.g., an S-CTS frame). Trigger frame 430 can be a frame for uplink OFDMA random access (UORA) resource allocation. For example, trigger frame 430 can be a frame for allocating uplink resources to STA 2 105 and STA 3 107, which sent PR frame 420. Uplink resources can be allocated to STA 2 105 and STA 3 107 by referring to information included in the common information field and user information field of trigger frame 430 (e.g., RA-RU (Random Access Resource Element) information included in the user information field). STA 2 105 and STA 3 107 may send uplink frame 440 to each OFDMA subchannel (e.g., resource element) after a certain period of time (e.g., SIFS time) following the receipt of trigger frame 430. AP 1 101 may receive uplink frame 440 from STA 2 105 and STA 3 107 and send response frames (e.g., BA frames) to STA 2 105 and STA 3 107.

[0076] Figure 5a and Figure 5b A third implementation scheme for a communication method utilizing preemption in a wireless local area network system is shown. Figure 5a and Figure 5b The third implementation scheme of a preemptive communication method in a wireless local area network system is illustrated in a partitioned manner.

[0077] refer to Figure 5a and Figure 5b AP 1 101, along with STA 1 103, STA 2 105, and STA 3 107 connected to AP 1 101, are operational. AP 1 101 can perform EDCA backoff operations to acquire a TXOP. Within the TXOP acquired by AP 1 101, AP 1 101 can transmit one or more frames (e.g., PPDU (Physical Layer Protocol Data Unit), MPDU (Media Access Control Layer Protocol Data Unit), A-MPDU (Aggregated MPDU)). The PPDU transmitted by AP 1 101 may include one or more A-MPDUs or MPDUs.

[0078] AP 1 101 can send the first frame 500 of the TXOP. The first frame 500 can be a MU-RTS frame. If the first frame sent is a MU-RTS frame, the AID in the user information field of the MU-RTS frame 500 can indicate STA 1 103. STA 1 103 can refer to the parameters of the first MU-RTS frame 500 sent (e.g., the channel and resource element for sending the CTS frame) to send a CTS frame after a certain period of time (e.g., PIFS, SIFS, or XIFS for preemption operations) starting from the end time of the transmission of the MU-RTS frame 500 sent by AP 1 101.

[0079] AP 1 101 may send a DL PPDU to STA 1 103 after a certain period of time following the receipt of a CTS frame (e.g., PIFS, SIFS time, or XIFS time for preemption operations).

[0080] The DL PPDU 510 transmitted from AP 1 101 to STA 1 103 includes a preemption indicator (e.g., bits included in the PHY preamble, bits included in the MAC header, subfields, information elements, or indicator bits, etc.). The preemption indicator can be included in various forms in the frame 510 transmitted from AP 1 101 to STA 1 103. The preemption indicator can indicate whether preemption is possible for a certain period of time (e.g., PIFS, SIFS, or XIFS time used for preemption operations) starting from the end time of transmission of the DL PPDU 510. When the preemption indicator indicates that preemption is possible, at the end of the transmission of the PPDU including the preemption indicator, one or more STAs (e.g., STA 2 105 and STA 3 107) that need to perform the preemption operation listen to the channel for the XIFS time or a period shorter than the XIFS time used for preemption operations. One or more STAs may send a PR (preemption request) frame (e.g., S-CTS (synchronization CTS)) 520 to AP 1 101 during the XIFS time period to notify that there are LL packets to be sent. The S-CTS frame 520 may be a CTS frame sent by one or more STAs.

[0081] STA 2 105 and STA 3 107 can refer to the parameters of the first MU-RTS frame 500 (e.g., the channel for transmitting the CTS frame) to simultaneously transmit PR frame 520 after a time shorter than the XIFS time used for preemption operations (e.g., SIFS time) from the end time of the transmission of DL PPDU 510 transmitted from AP 1 101, so as to transmit LL packets generated during the transmission period of DL PPDU 510 of AP 1 101 to AP 1 101. The SCRAMBLER_INITIAL_VALUE of the TXVECTOR parameter present in the PHY preamble of S-CTS frame 520 is set to be the same as the SCRAMBLER_INITIAL_VALUE of the RXVECTOR parameter present in MU-RTS frame 500. That is, the S-CTS frame is configured identically in all STAs based on the SCRAMBLER_INITIAL_VALUE value of the RXVECTOR parameter present in MU-RTS frame 300. Therefore, S-CTS frames will not conflict with each other.

[0082] Sub-channels (e.g., OFDMA sub-channels, resource units) for transmitting PR frames 520 can be allocated according to scheduling priorities. For example, the channel for transmitting PR frames 520 can be divided into N (N is a natural number, e.g., 3) OFDMA sub-channels, and some of these N OFDMA sub-channels can be used by STAs that should transmit high-priority data. Some of these N OFDMA sub-channels can be used by STAs that should transmit normal-priority data. Some of these N OFDMA sub-channels can be used by STAs that should transmit low-priority data. That is, priorities can be determined based on the number of sub-channels. The mapping between priorities and sub-channels can be agreed upon or negotiated in advance. Alternatively, among all channels that can transmit PR frames 520 (e.g., 40MHz channels, 80MHz channels, 160MHz channels, 320MHz channels), specific 20MHz channels can be used according to priorities. For example, in an 80MHz channel consisting of four 20MHz channels, the primary 20MHz channel can always be used when transmitting PR frames 520. Using the primary 20MHz channel can mean being able to transmit low-priority traffic. If a PR frame 520 is transmitted using a sub-20MHz channel, it indicates the transmission of a normal priority frame. If a PR frame 520 is transmitted using a sub-40MHz channel, it indicates the transmission of a high priority frame. Priority-channel mapping can be pre-agreed or negotiated. That is, depending on whether a specific sub-channel or a specific channel is used (e.g., a specific 20MHz channel, 40MHz channel, 80MHz channel, or 160MHz channel), the AP can know the priority of the STA's traffic transmission. Traffic priority can be determined based on delay thresholds. That is, traffic arriving earlier at the delay threshold can be assigned a higher priority. The delay threshold can be the point in time when a frame is dropped or invalidated in the STA's transmission queue. Traffic or frames arriving earlier at the delay threshold are more urgent. Alternatively, traffic priority can be determined based on QoS parameters (e.g., TID, AC). Alternatively, traffic priority can be determined by considering both delay thresholds and QoS parameters.

[0083] The AP can allocate uplink resources based on the priority of the traffic to be transmitted by the STA. For example, traffic priorities can be divided into three categories: "high," "normal," and "low." Alternatively, traffic priorities can be configured more simply or in more diverse ways. The AP can perform uplink traffic scheduling based on traffic priorities. For example, the AP can allocate uplink resources to high-priority traffic first, or provide more transmission resources to high-priority traffic. After receiving PR frame 520, AP 1101 can send trigger frame 530 after a certain period of time (e.g., XIFS time, PIFS time, SIFS time for preemption). Trigger frame 530 can be a frame used for UORA (Uplink OFDMA Random Access) resource allocation.

[0084] AP 1 101 can send trigger frame 530 to trigger high-priority traffic. Trigger frame 530 may include information (e.g., RA-RU (Random Access Resource Element) information for UORA) for allocating resources to STAs (e.g., STA 2 105) that are sending S-CTS frame 520 on the high-priority channel, and the STA sending S-CTS frame 520 can send uplink frame 540 on the uplink resources allocated by the AP using trigger frame 530. The AP can send response frames (e.g., BA frames) to the STAs.

[0085] After allocating high-priority uplink resources, AP 1 101 can send trigger frame 531 to trigger normal-priority traffic. Trigger frame 531 may include information (e.g., RA-RU (Random Access Resource Element) information for UORA) for allocating resources to STAs (e.g., STA 2 105, STA 3 107) that are sending S-CTS frames 520 on the normal-priority channel, and the STAs sending S-CTS frames 520 on the normal-priority channel can send uplink frames 550 on the uplink resources allocated by the AP using trigger frame 531. The AP can send response frames (e.g., BA frames) to the STAs.

[0086] After allocating uplink resources with normal priority, AP 1 101 can send trigger frame 533 to trigger low-priority traffic. The trigger frame may include information (e.g., RA-RU (Random Access Resource Element) information for UORA) for allocating resources to STAs (e.g., STA 3107) that are sending S-CTS frame 520 on low-priority channels, and STAs sending S-CTS frame 520 on high-priority channels can send uplink frame 560 on the uplink resources allocated by the AP using trigger frame 533. The AP can send response frames (e.g., BA frames) to the STAs.

[0087] In this implementation, traffic priority can be determined based on a delay threshold (within which frames should be transmitted). The earlier the delay threshold is reached, the higher the traffic priority can be. Alternatively, traffic priority can be determined based on QoS parameters. Traffic priority can be determined by taking both delay thresholds and QoS parameters into account. The delay threshold can be the point in time at which a frame is dropped or invalidated in the STA's transmission queue. Traffic or frames that arrive earlier than the delay threshold are more urgent.

[0088] According to one embodiment of the invention, other types of trigger frames and response frames can be used instead of NFRP trigger frames and NDP feedback. For example, when AP 1 uses BSRP (Buffer Status Report Polling) trigger frames instead of NFRP trigger frames, and STA 2 and STA 3 receive BSRP trigger frames, STA 2 and STA 3 can send BSR (Buffer Status Report) frames. The BSR frame can indicate queue information for STA 2 and STA 3. The BSR frame can be a frame that includes BSR information in the form of A-Control in the MAC header of a QoS empty frame. AP 1 can receive BSRs from STA 2 and STA 3 on a specific frequency (e.g., OFDMA subcarriers, subchannels, etc. mapped according to traffic priority). AP 1 schedules trigger frames according to the frequency at which BSR frames are sent and the information included in the BSR frames.

[0089] Figure 6a and Figure 6b A fourth implementation scheme for a communication method utilizing preemption in a wireless local area network system is shown. Figure 6a and Figure 6b The third implementation scheme of a preemptive communication method in a wireless local area network system is illustrated in a partitioned manner.

[0090] Figure 6c and Figure 6d A fifth implementation of a communication method utilizing preemption in a wireless local area network system is shown. Figure 6c and Figure 6d The third implementation scheme of a preemptive communication method in a wireless local area network system is illustrated in a partitioned manner.

[0091] refer to Figures 6a to 6dAP 1 101, along with STA 1 103, STA 2 105, and STA 3 107 connected to AP 1 101, are operational. AP 1 101 can perform an EDCA backoff operation to acquire a TXOP. Within the TXOP acquired by AP 1 101, AP 1 101 can send one or more frames (e.g., PPDU (Physical Layer Protocol Data Unit), MPDU (Media Access Control Layer Protocol Data Unit), A-MPDU (Aggregated MPDU)). The PPDU sent by AP 1 101 may include one or more A-MPDUs or MPDUs. AP 1 101 can send an RTS frame 600 to STA 1 103 within the TXOP. AP 1 101 can send a DL PPDU 610 to STA 1 103 after a certain period of time following the receipt of a CTS frame (e.g., PIFS, SIFS, or XIFS for preemption operations).

[0092] refer to Figure 6a and Figure 6bThe DL PPDU 610 transmitted from AP 1 101 to STA 1 103 includes a preemption indicator (e.g., bits included in the PHY preamble, bits included in the MAC header, subfields, information elements, or indicator bits, etc.). The preemption indicator can be included in various forms in the frame 610 transmitted from AP 1 101 to STA 1 103. The preemption indicator can indicate whether preemption is possible for a certain period of time (e.g., PIFS, SIFS, or XIFS for preemption operation) starting from the end time of transmission of the DL PPDU 610. AP 1 101 may include an NFRP (Null Data PPDU) feedback report polling (NDP) trigger frame in the form of an A-MPDU in the DL PPDU. Alternatively, an NFRP trigger frame may be transmitted separately after a certain period of time (e.g., SIFS) starting from the end time of transmission of the DL PPDU 610. The feedback type included in the user information field of the NFRP trigger frame can be set to a separate type to indicate the presence of low-latency traffic. An NFRP trigger frame with a separate feedback type setting to indicate the presence of low-latency traffic can be a preemption indicator. When the preemption indicator in the DLPPDU indicates that preemption is possible and includes an NFRP trigger frame, or when the preemption indicator in DL PPDU 610 indicates that preemption is possible and sends an NFRP trigger frame separately, one or more STAs (e.g., STA 2 105 and STA 3 107) that need to perform preemption operations can send a PR (preemption request) frame 620 to AP 1 101 during the XIFS time to notify of the presence of LL packets to be sent. Here, a signal (e.g., an NDP feedback report) can be sent instead of the PR frame 620. For example, one or more STAs can send the PR frame 620 to AP 1 101 after the SIFS time. PR frame 620 can be simultaneously initiated by STA 2 105 and STA 3 107. For example, NDP feedback report 610 can be a feedback signal transmitted by the STA for each frequency element present in the channel. A frequency element (tone) is an OFDMA subcarrier.

[0093] refer to Figure 6c and Figure 6dThe DL PPDU 610 transmitted from AP 1 101 to STA 1 103 includes a preemption indicator (e.g., bits included in the PHY preamble, bits included in the MAC header, subfields, information elements, or indicator bits). The preemption indicator can be included in various forms in the frame transmitted from AP 1 to STA 1 103. The preemption indicator can indicate whether preemption is possible for a certain period of time (e.g., PIFS, SIFS, or XIFS time used for preemption operations) starting from the end time of transmission of the DL PPDU 610. If the preemption indicator in DL PPDU 610 indicates that preemption is possible, one or more STAs (e.g., STA 2 105 and STA 3 107) that need to perform the preemption operation at the end time of PPDU 610 including the preemption indicator may send at least one of a PR (Preemption Request) frame 620 or a signal (e.g., NDP Feedback Report) 621 to AP 1 101 during the XIFS period to notify of the presence of an LL packet to be sent. For example, one or more STAs may send the PR frame 620 to AP 1 101 after the SIFS period. The PR frame 620 may be started simultaneously by STA 2 105 and STA 3 107. When AP 1 101 receives the PR frame 620, it knows that the STA has requested preemption. AP 1 101 may send an NFRP trigger frame 611 during the SIFS period after receiving the PR frame 620. The feedback type included in the user information field of the NFRP trigger frame 611 can be set to a separate type to indicate the presence of low-latency traffic. The NFRP trigger frame 611 set to a separate feedback type to indicate the presence of low-latency traffic can be a preemption indicator. STA2 105 and STA 3 107 can send an NDP feedback report frame 621 in response to the NFRP trigger frame 611. The NDP feedback report 621 can be a feedback signal sent by the STA for each frequency element present in the channel. The frequency element is an OFDMA subcarrier.

[0094] refer to Figures 6a to 6dIn NDP Feedback Report 621, STA 2 105 and STA 3 107 can send feedback signals on specific frequency units based on traffic priority. For example, there can be 242 available frequency units. Of these 242 frequency units, 80 can be used for transmitting feedback of low-priority traffic, 80 can be used for transmitting feedback of normal-priority traffic, and 82 can be used for transmitting feedback of high-priority traffic. Traffic priority and frequency unit mapping can be pre-negotiated or agreed upon. AP 1 101 can determine the priority of the uplink traffic to be transmitted based on the NDP Feedback Report 621 signals sent by STA 2 105 and STA 3 107.

[0095] The AP can allocate uplink resources to the STA after a certain period of time (e.g., SIFS time) following the transmission of the STA's NDP feedback report 621. The AP can allocate uplink resources based on the priority of the traffic the STA should transmit. For example, traffic priorities can be divided into three levels: "high," "normal," and "low." Alternatively, traffic priorities can be configured in a simplified or more diverse manner. The AP can perform uplink traffic scheduling based on traffic priorities. For example, the AP can allocate uplink resources to high-priority traffic first, or provide more transmission resources to high-priority traffic. After receiving the PR frame 620 or a signal (e.g., NDP feedback report, 621), AP 1 101 can send a trigger frame 630 after a certain period of time (e.g., XIFS time, PIFS time, SIFS time for preemption). The trigger frame 630 can be a frame used for UORA (Uplink OFDMA Random Access) resource allocation.

[0096] AP 1 101 can send trigger frame 630 to trigger high-priority traffic. Trigger frame 630 may include information for allocating resources (e.g., RA-RU (Random Access Resource Element) information for UORA) to STAs (e.g., STA 2 105) that are sending NDP feedback reports 621 on high-priority frequency units, and the STA sending NDP feedback reports 621 on the high-priority channel can send uplink frames 640 on the uplink resources allocated by the AP using trigger frame 630. The AP can send response frames (e.g., BA frames) to the STAs.

[0097] After AP 1 101 schedules high-priority traffic, AP 1 101 can send trigger frame 631 to trigger normal-priority traffic. Trigger frame 631 may include information for allocating resources (e.g., RA-RU (Random Access Resource Element) information for UORA) to STAs (e.g., STA 1 103, STA 2 105) that are sending NDP feedback reports 621 on normal-priority frequency units, and the STAs sending NDP feedback reports 621 on normal-priority channels can send uplink frames 650 on the uplink resources allocated by the AP using trigger frame 631. The AP can send response frames (e.g., BA frames) to the STAs.

[0098] After AP 1 101 schedules normal priority traffic, AP 1 101 can send trigger frame 633 to trigger low priority traffic. Trigger frame 633 may include information for allocating resources (e.g., RA-RU (Random Access Resource Element) information for UORA) to STAs (e.g., STA 1 103, STA 2 105) that are sending NDP feedback reports 621 on low priority frequency elements, and the STAs sending NDP feedback reports 621 on low priority channels can send uplink frames 660 on the uplink resources allocated by the AP using trigger frame 633. The AP can send response frames (e.g., BA frames) to the STAs.

[0099] In this implementation, traffic priority can be determined based on a delay threshold (within which frames should be transmitted). The earlier the delay threshold is reached, the higher the traffic priority. Alternatively, traffic priority can be determined based on QoS parameters. Traffic priority can also be determined by taking both delay thresholds and QoS parameters into account.

[0100] The delay threshold can be the point in time at which a frame is dropped or invalidated in the STA's transmission queue. Traffic or frames that arrive earlier than the delay threshold are more urgent.

[0101] According to one embodiment of the invention, other types of trigger frames and response frames can be used instead of NFRP trigger frames and NDP feedback. For example, when AP 1 uses BSRP (Buffer Status Report Polling) trigger frames instead of NFRP trigger frames, and STA 2 and STA 3 receive BSRP trigger frames, STA 2 and STA 3 can send BSR (Buffer Status Report) frames. The BSR frame can indicate queue information for STA 2 and STA 3. The BSR frame can be a frame that includes BSR information in the form of A-Control in the MAC header of a QoS empty frame. AP 1 can receive BSRs from STA 2 and STA 3 on a specific frequency (e.g., OFDMA subcarriers, subchannels, etc. mapped according to traffic priority). AP 1 schedules trigger frames according to the frequency at which BSR frames are sent and the information included in the BSR frames.

[0102] Figure 7a and Figure 7b A sixth implementation of a communication method utilizing preemption in a wireless local area network system is shown. Figure 7a and Figure 7b The third implementation scheme of a preemptive communication method in a wireless local area network system is illustrated in a partitioned manner.

[0103] refer to Figure 7a and Figure 7b AP 1 101, along with STA 1 103, STA 2 105, and STA 3 107 connected to AP 1 101, are operational. AP 1 101 can perform an EDCA backoff operation to acquire a TXOP. Within the TXOP acquired by AP 1 101, AP 1 101 can transmit one or more frames (e.g., Physical Layer Protocol Data Units (PPDUs), Medium Access Control Layer Protocol Data Units (MPDUs), and Aggregated MPDUs (A-MPDUs)). The PPDUs transmitted by AP 1 101 may include one or more A-MPDUs or MPDUs. AP 1 101 can transmit an RTS frame 700 to STA 1 103 within the TXOP. AP 1 101 may send DL PPDU 710 to STA 1 103 after a certain period of time following the receipt of a CTS frame (e.g., PIFS, SIFS time, or XIFS time for preemption operation).

[0104] The DL PPDU 710 transmitted from AP 1 101 to STA 1 103 includes a preemption indicator (e.g., bits included in the PHY preamble, bits included in the MAC header, subfields, information elements, or indicator bits, etc.). The preemption indicator can be included in various forms in the frame transmitted from AP 1 101 to STA 1 103. The preemption indicator can indicate whether preemption is possible for a certain period of time (e.g., PIFS, SIFS, or XIFS time used for preemption operations) starting from the end time of transmission of the DL PPDU 710. The DL PPDU 710 of AP 1 101 can be a DL MU (Multi-User) PPDU. For example, some OFDMA resource elements (e.g., OFDMA subchannels) of the DL PPDU 710 transmitted by AP 1 101 can be utilized when transmitting data frames, and some OFDMA resource elements can be utilized when transmitting NFRP (NDP (Null Data PPDU) Feedback Report Polling) trigger frame 711. The feedback type included in the user information field of the NFRP trigger frame 711 can be set to a separate type to indicate the presence of low-latency traffic. The NFRP trigger frame 711 set to a separate feedback type to indicate the presence of low-latency traffic can be a preemption indicator. If the preemption indicator in the DL PPDU 710 indicates that preemption is possible and includes the NFRP trigger frame 711, then at the end of the transmission of the PPDU 710 including the preemption indicator, one or more STAs (e.g., STA 2 105 and STA 3 107) can send a PR (preemption request) frame or signal 720 to AP 1 101 during the XIFS time to notify of the presence of LL packets to be transmitted. For example, signal 720 can be an NDP feedback report. For example, one or more STAs can send the PR frame 720 to AP 1 101 after the SIFS time. The PR frame 720 can be started simultaneously by STA 2 105 and STA 3 107. For example, the NDP feedback report 720 can be a feedback signal sent by the STA for each frequency element present in the channel. The frequency element is an OFDMA subcarrier.

[0105] In the NDP Feedback Report 720, STA 2 105 and STA 3 107 can send feedback signals on specific frequency units based on traffic priority. For example, there can be 242 available frequency units. Of these 242 frequency units, 80 can be used for transmitting feedback of low-priority traffic, 80 can be used for transmitting feedback of normal-priority traffic, and 82 can be used for transmitting feedback of high-priority traffic. The traffic priority and frequency unit mapping can be pre-negotiated or agreed upon. AP 1 101 can determine the priority of the uplink traffic to be transmitted based on the NDP Feedback Report 720 signals sent by STA 2 105 and STA 3 107.

[0106] The AP can allocate uplink resources to the STA after a certain period of time (e.g., SIFS time) following the transmission of the STA's NDP feedback report 720. The AP can allocate uplink resources based on the priority of the traffic the STA should transmit. For example, traffic priorities can be divided into three levels: "high," "normal," and "low." Alternatively, traffic priorities can be configured in a simplified or more diverse manner. The AP can perform uplink traffic scheduling based on traffic priorities. For example, the AP can allocate uplink resources to high-priority traffic first, or provide more transmission resources to high-priority traffic. The AP 1101 can send a trigger frame 730 after a certain period of time (e.g., XIFS time, PIFS time, SIFS time for preemption) following the receipt of the PR frame or signal 720. The trigger frame 730 can be a frame used for UORA (Uplink OFDMA Random Access) resource allocation.

[0107] AP 1 101 can send a trigger frame 730 to trigger high-priority traffic. The trigger frame may include information for allocating resources (e.g., RA-RU (Random Access Resource Element) information for UORA) to STAs (e.g., STA 2 105) that send NDP feedback reports 720 on high-priority frequency units, and the STAs sending NDP feedback reports 720 on high-priority channels may send uplink frames 740 on the uplink resources allocated by the AP using trigger frame 730. The AP may send response frames (e.g., BA frames) to the STAs.

[0108] After AP 1 101 schedules high-priority traffic, AP 1 101 can send a trigger frame 731 to trigger normal-priority traffic. Trigger frame 731 may include information for allocating resources (e.g., RA-RU (Random Access Resource Element) information for UORA) to STAs (e.g., STA 1 103, STA 2 105) that are sending NDP feedback reports 720 on normal-priority frequency units. STAs sending NDP feedback reports 720 on normal-priority channels can send uplink frames 750 on the uplink resources allocated by the AP using trigger frame 731. The AP can send response frames (e.g., BA frames) to the STAs.

[0109] After AP 1 101 schedules normal priority traffic, AP 1 101 can send a trigger frame 733 to trigger low priority traffic. The trigger frame 733 may include information for allocating resources (e.g., RA-RU (Random Access Resource Element) information for UORA) to STAs (e.g., STA 1 103, STA 2 105) that are sending NDP feedback reports 720 on low priority frequency elements, and the STAs sending NDP feedback reports 720 on low priority channels can send uplink frames 760 on the uplink resources allocated by the AP using trigger frame 733. The AP can send response frames (e.g., BA frames) to the STAs.

[0110] In this implementation, traffic priority can be determined based on a delay threshold (within which frames should be transmitted). The earlier the delay threshold is reached, the higher the traffic priority. Alternatively, traffic priority can be determined based on QoS parameters. Traffic priority can also be determined by taking both delay thresholds and QoS parameters into account.

[0111] The delay threshold can be the point in time at which a frame is dropped or invalidated in the STA's transmission queue. Traffic or frames that arrive earlier than the delay threshold are more urgent.

[0112] According to one embodiment of the invention, other types of trigger frames and response frames can be used instead of NFRP trigger frames and NDP feedback. For example, when AP 1 uses BSRP (Buffer Status Report Polling) trigger frames instead of NFRP trigger frames, and STA 2 and STA 3 receive BSRP trigger frames, STA 2 and STA 3 can send BSR (Buffer Status Report) frames. The BSR frame can indicate queue information for STA 2 and STA 3. The BSR frame can be a frame that includes BSR information in the form of A-Control in the MAC header of a QoS empty frame. AP 1 can receive BSRs from STA 2 and STA 3 on a specific frequency (e.g., OFDMA subcarriers, subchannels, etc. mapped according to traffic priority). AP 1 schedules trigger frames according to the frequency at which BSR frames are sent and the information included in the BSR frames.

[0113] Figure 8 A seventh implementation of a communication method utilizing preemption in a wireless local area network system is shown.

[0114] refer to Figure 8 AP 1101, along with STA 1103, STA 2 105, and STA 3 107 connected to AP 1101, are operational. AP 1101 can perform an EDCA backoff operation to acquire a TXOP. Within the TXOP acquired by AP 1101, AP 1101 can send one or more frames (e.g., PPDU (Physical Layer Protocol Data Unit), MPDU (Media Access Control Layer Protocol Data Unit), A-MPDU (Aggregated MPDU)). The PPDU sent by AP 1101 may include one or more A-MPDUs or MPDUs. AP 1101 can send an RTS frame 800 to STA 1103 within the TXOP. AP 1101 can send a DL PPDU to STA 1103 after a certain period of time following the receipt of a CTS frame (e.g., PIFS, SIFS time, or XIFS time used for preemption operations).

[0115] In this implementation, it is assumed that the DL PPDU 810 of AP 1 101 follows the DL MU (Multi-User) PPDU format. For example, some OFDMA resource elements (e.g., OFDMA sub-channels) of the DL PPDU 810 sent by AP 1 101 can be utilized when transmitting data frames, and some OFDMA resource elements (RUs) can be utilized when transmitting NFRP (Null Data PPDU) feedback report polling) trigger frames 811. In existing WLAN technologies, NFRP trigger frames 811 are prohibited from being included in the MUPPDU (Multi-User Physical Layer Protocol Data Element) format, but EHT MU or later WLAN standards define that MUPPDUs can exceptionally include NFRP trigger frames 811. In this case, the SIG-B field of the preamble of MU PPDU 810 includes a broadcast AID. The broadcast AID indicates the resource allocation information of the RUs that include NFRP trigger frames 811. Using the resource allocation information of the RU, a terminal that needs to participate in priority transmission can locate the RU that transmitted the NFRP trigger frame 811. Furthermore, at least one terminal that needs to participate in priority transmission can parse the information in the preamble and MPDU of subsequent sequences. This is because even if the RA field of the first frame of any TXOP does not indicate a terminal that needs to participate in priority transmission, the frame that triggers priority transmission can still be included in subsequent sequences.

[0116] The NFRP trigger frame 811 transmitted via a specific RU of MU PPDU 810 includes indicators for collecting information about LL packets of terminals that need to participate in priority transmission. The indicators for collecting information about LL packets may include starting AID information indicating frequency unit allocation information for NFR, time length information of subsequent priority transmission sequences (preemption duration), maximum value of delay limits allowed to participate in NFR (maximum allowed delay limits), information about the maximum size or transmission time of LL packets allowed to participate in NFR (maximum allowed LL packet size (tx duration)), a flag indicating the presence of wildcard frequency units (wildcard flag), and indicators (e.g., the number of frequency unit groups) for notifying information about each frequency unit group when grouping frequency units for NFRP.

[0117] The feedback type included in the user information field of the NFRP trigger frame 811 can be set to a separate type to indicate the presence of low-latency traffic. The NFRP trigger frame 811 set to a separate feedback type to indicate the presence of low-latency traffic can be a preemption indicator. When the preemption indicator in the DL PPDU 810 indicates that preemption is possible and includes the NFRP trigger frame 811, at the end of the transmission time of the PPDU 810 including the preemption indicator, one or more STAs (e.g., STA 2 105 and STA 3 107) can send a PR frame or signal 820 to AP 1 101 during the XIFS time to notify of the presence of LL packets to be transmitted. Here, signal 820 can be an NDP feedback report. For example, one or more STAs can send the PR frame 820 to AP 1 101 after the SIFS time. The PR frame can be sent simultaneously by STA 2 105 and STA 3 107. For example, the NDP Feedback Report (NFR) 820 can be a feedback signal sent by the STA for each frequency element present in the channel. The frequency element is an OFDMA subcarrier.

[0118] According to this implementation scheme, since STA 1 103 cannot receive NFRP trigger frames 811 directed to a single RU, in order to confirm STA 1 103's intention to participate in priority transmission, NFRP trigger frames 811 (which include STA 1 103's DL data) can be sent to a specific MPDU of the A-MPDU sent to the RU, or a separate header information for sending NFRP information can be configured and sent by including it in the header of the DL data MPDU in the form of trigger response scheduling control.

[0119] Among the terminals that have received NFRP trigger frame 811, those needing to participate in priority transmission determine the frequency unit based on the information indicated by NFRP. Terminals needing to participate in priority transmission send an NDP feedback report 820 using the corresponding frequency unit. AP 1 101 can trigger uplink priority transmission by sending trigger frame 830 using the collected NRF information. Terminals instructed to send an uplink TB PPDU via the user information field of trigger frame 830 send LL packets to AP 1 101. In this case, the terminal should include the LL packets specified in NFR 820 in the TB PPDU and send them with the highest priority. If there is still space in the allocated RU after all LL packets specified in NFR 820 have been sent, the terminal can send additional packets in the form of A-MPDU according to the AC priority.

[0120] Because terminals participating in priority transmissions do not win the TXOP through EDCA contention, this can lead to an imbalance in fairness compared to terminals that do not participate in priority transmissions. Therefore, it may be necessary to impose some restrictions on future priority transmissions or EDCA contention for terminals that successfully transmit LL packets through priority transmissions. For example, a terminal that receives an instruction to send an LL packet in a trigger frame after an NFRP sequence, sends data in a TB PPDU, and receives an ACK from AP 1 101 can apply a set of MU EDCA parameters that adjusts the channel connection strength (typically reducing the connection strength) to the AC that received the ACK from AP 1 102. Alternatively, based on values ​​agreed upon between AP 1 101 and the terminal (according to an association procedure or a separate establishment procedure), terminals can be prevented from responding to NFRP for a specified number of time periods or a specified time interval. While fairness can be adjusted through priority transmission participation restrictions, exceptions can be added to minimize timeouts due to restricted terminals exceeding delay limits. For example, if the minimum delay limit value in each AC queue is below a preset threshold, participation in NFRP can be allowed regardless of priority transmission participation restrictions. Furthermore, since applying the MU EDCA parameter set to the AC may set an excessively large backoff counter, preventing transmission attempts within the delay limit, the application of the MU EDCA parameter set can only be disabled when the minimum delay limit is below a preset threshold, and EDCA contention can be performed using the general EDCA parameter set. Specifically, in this case, the MU EDCA timer can be treated as 0, and the AC's backoff counter can be reset based on the general EDCA parameter set. At this point, the existing MU EDCA timer can be stopped or allowed to continue decreasing. If the existing MU EDCA timer is maintained, a terminal that successfully sends an LL packet after acquiring a TXOP using the general EDCA parameter set may need to reapply the MU EDCA parameter set and perform a backoff operation based on the MU EDCA parameter set.

[0121] according to Figure 8 In the implementation scheme, the NFRP trigger frame or related control header information may include one or more of the following: initial AID information for indicating frequency unit allocation information for NFR, time length information of subsequent priority transmission sequences (preemption duration), maximum delay limit allowed to participate in NFR (maximum allowed delay limit), information about the maximum size or transmission time of LL packets allowed to participate in NFR (maximum allowed LL packet size (tx duration)), a flag indicating the presence of wildcard frequency units (wildcard flag), and an indicator (e.g., the number of frequency unit groups) indicating information about each frequency unit group when grouping frequency units for NFRP.

[0122] Figure 9a A first embodiment of the frequency unit mapping structure and allocation method for NFRP (NDP Feedback Reporting Polling) in a wireless local area network system is shown. Figure 9a An implementation scheme for initiating NFR transmission by utilizing the initial AID information is shown.

[0123] refer to Figure 9a If there are a total of N frequency units in the frequency resources used for the NFRP sequence, the first frequency unit is assigned to a terminal whose AID equals the starting AID value, and the next frequency unit is assigned to the terminal corresponding to the starting AID+1, thereby initiating NFR transmission by specifying the terminal assigned to each frequency unit. Therefore, among the terminals that receive the NFRP trigger frame in the above manner, the terminal with the frequency unit corresponding to its own AID and needing to participate in LL packet priority transmission can transmit NFR on the corresponding frequency unit. If the NFRP trigger frame or control header information contains additional conditions for participating in priority transmission (e.g., delay limits or LL packet size (transmission time)), only terminals that meet these conditions can participate in NFR transmission. If the wildcard flag is activated, one or more terminals that do not meet the NFR transmission conditions but need to participate in LL packet priority transmission can transmit NFR on a separate frequency unit allocated to wildcard NFR transmission. In this case, it is unknown which terminal participates in the wildcard frequency unit, but the AP can consider performing an additional LL packet priority transmission sequence after performing the corresponding LL packet priority transmission sequence.

[0124] Figure 9b A second embodiment of the frequency unit mapping structure and allocation method for NFRP in a wireless local area network system is shown. Figure 9b An implementation scheme for triggering NFR transmission by utilizing information on the maximum allowed delay limit is shown.

[0125] refer to Figure 9bIf there are a total of N frequency units in the frequency resources used for the NFRP sequence, the value indicated in the maximum allowed delay limit information can be divided by N to set N delay limit intervals. Therefore, a terminal can send an NFR on the frequency unit corresponding to the interval to which the delay limit value of the LL packet to be sent belongs (excluding wildcard frequency units if the wildcard flag is enabled). In this case, since the AP cannot distinguish which terminal sent the NFR, if it needs to grant the terminal sending the NFR an opportunity to transmit LL packets on a specific frequency unit, it can use the frequency unit index information instead of the terminal AID in the user information field of the trigger frame to notify the terminal sending the NFR to send the LL packet on the indicated frequency unit index. When using this implementation, there is the advantage that the AP can trigger priority transmission of urgent LL packets. The wildcard flag can also be applied to this implementation in the same way, and if there are additional conditions such as the maximum LL packet size (tx duration), only terminals that can meet said conditions can be allowed to send NFRs.

[0126] Figure 9c A third implementation scheme for a frequency unit mapping structure and allocation method for NFRP in a wireless local area network system is shown. Figure 9c An implementation scheme for initiating NFR transmission by utilizing the maximum allowed LL packet size (tx duration) information is shown.

[0127] refer to Figure 9c If there are a total of N frequency units in the frequency resources used for the NFRP sequence, the value indicated in the maximum LL packet size (tx duration) information can be divided by N to set N delay limit intervals. Therefore, a terminal can send an NFR on the frequency unit corresponding to the interval to which the size or transmission time value of the LL packet to be sent belongs (excluding wildcard frequency units if the wildcard flag is enabled). In this case, since the AP cannot distinguish which terminal sent the NFR, if it needs to grant the terminal sending the NFR an opportunity to transmit LL packets on a specific frequency unit, it can use the frequency unit index information instead of the terminal AID in the user information field of the trigger frame to notify the terminal sending the NFR to transmit the LL packet on the indicated frequency unit index. When using this implementation, there is an advantage that the AP can maximize resource allocation efficiency when scheduling LL packet priority transmission. The wildcard flag can be applied to this implementation, and if there are additional conditions such as maximum delay limits, only terminals that can meet said conditions can be allowed to send NFRs.

[0128] Figure 9d A fourth embodiment of the frequency unit mapping structure and allocation method for NFRP in a wireless local area network system is shown.Figure 9d An implementation scheme for triggering NFR transmission by utilizing information on the number of frequency unit segments is shown.

[0129] refer to Figure 9d When there are a total of N frequency units in the frequency resources used for NFRP sequences, M frequency unit segments can be set up by dividing the N frequency units according to the value (M) indicated in the frequency unit segmentation number information. According to this implementation, each frequency unit segment can allocate frequency units by combining two or more pieces of information, including the start AID, the maximum allowed delay limit, and the maximum allowed LL packet size (tx duration). For example, each first frequency unit segment can divide the maximum LL packet size into M segments, so that a terminal that needs to send LL packets corresponding to the first LL packet size segment can send NFRs on the corresponding frequency band according to the start AID conditions. According to this implementation, the following advantages exist: the conditions for LL packets intended to trigger NFR transmission can be specified, and it is possible to identify which terminal sent the NFR.

[0130] The preemption operation of the AP and STA according to embodiments of the present invention will be described below. The AP is connected to or associated with at least one STA. For example, the AP may be connected to or associated with a first STA, a second STA, and a third STA. The AP and at least one STA may use at least one channel, subchannel, or subcarrier to perform transmission or reception. In other words, the AP and at least one STA may use at least one subchannel or subcarrier to transmit or receive frames. For example, the AP and at least one STA may transmit or receive frames on each of a plurality of subchannels. As another example, the AP and at least one STA may use a plurality of subchannels to transmit or receive frames. Here, a subchannel or subcarrier may be at least a portion of the frequency band of the channel connecting the STA and the AP. At least one subchannel or subcarrier may be referred to as a resource element (RU) or a frequency element (tone). The STA and AP may perform a preemption operation. Here, a preemption operation refers to the operation or process for sending LL data packets or LL traffic by an STA or AP that has not yet acquired a TXOP. In other words, it refers to the aforementioned priority transmission.

[0131] Figure 10 A flowchart illustrating a process for an access point (AP) to perform a preemption operation according to one embodiment of the present invention is shown. Figure 10 The process is performed by the AP receiving the preempted data. Preempted data refers to data transmitted through a preemption operation. Preempted data can include, for example, LL packets or LL traffic.

[0132] refer to Figure 10 In step S1001, the AP sends an initial frame (e.g., Figure 3The initial frame (300) may be referred to as the first frame. The initial frame is the first frame transmitted after obtaining the TXOP. For example, the initial frame includes MU-RTS frames and RTS frames. The initial frame is sent to at least one STA connected to the AP. The AP may perform a channel access operation before sending the initial frame. The channel access operation may include, for example, an EDCA backoff operation. The channel access operation is the procedure used to execute a frame. For example, the AP can obtain the TXOP by performing a channel access operation. The AID in the user information field of the initial frame may indicate at least one STA.

[0133] In step S1003, the AP sends a frame including a preemption indicator (e.g., Figure 3 DL PPDU 310 in the text. Frames including preemption indicators can include PPDU, A-MPDU, and MDPU. Frames including preemption indicators can be frames comprising multiple frames. For example, frames including preemption indicators can include NFRP (Null Data PPDU) feedback report polling (NDP) triggered frames (e.g., Figure 7a The NFRP trigger frame (711) and MU-RTS frame are included. A frame including a preemption indicator can be transmitted using at least one subchannel or subcarrier. The preemption indicator indicates whether a preemption operation is possible within a predefined time from the end time of transmission of the frame including the preemption indicator. The preemption indicator is included in the frame in various forms. For example, the preemption indicator can take the form of bits included in the PHY preamble, bits included in the MAC header, subfields, information elements, or indicator bits. Alternatively, the NFRP trigger frame can be used as a preemption indicator if the feedback type of the NFRP trigger frame is a type used to indicate the presence of preemption data. That is, an NFRP trigger frame with a feedback type used for preemption operation can be considered a preemption indicator. The broadcast AID of the frame including the preemption indicator can include resource allocation information for the subchannel or subcarrier on which the NFRP trigger frame is transmitted.

[0134] In step S1005, the AP receives a frame indicating a preemption operation. Here, the frame indicating the preemption operation can be referred to as the second frame. The frame indicating the preemption operation can be a signal or frame indicating the presence of preemption data to be transmitted. For example, the frame indicating the preemption operation may include a PR frame (e.g., S-CTS frame 320 in FIG5) or a signal indicating the presence of preemption data (e.g., ...). Figure 6cAt least one of the NDP feedback reports (621). The frame indicating a preemption operation can be received within a predefined time from the end time of transmission of the frame including the preemption indicator, and can be received based on the parameters of the initial frame. At least one parameter of the frame indicating a preemption operation can be the same as the parameter of the initial frame. For example, the SCRAMBELR_INITIAL_VALUE of the TXVECTOR parameter of the PR frame can be the same as the SCRAMBELR_INITIAL_VALUE of the RXVECTOR parameter of the initial frame. The frame indicating a preemption operation can be used to indicate the priority of preempted data. The priority can be indicated based on the channel used to transmit the frame indicating a preemption operation. For example, a priority can be predefined for each channel, and the priority of preempted data can be indicated based on the priority of the channel receiving the frame indicating a preemption operation. As another example, the priority can be indicated based on the bandwidth of the channel used to transmit the frame indicating a preemption operation. For example, preemption data based on a frame indicating preemption operation transmitted using a 40 MHz channel may have a higher priority than preemption data based on a frame indicating preemption operation transmitted using a 20 MHz channel. The priority of preemption data may be determined based on at least one of a delay limit or a QoS parameter.

[0135] In step S1007, the AP sends a trigger frame (e.g., Figure 3 The trigger frame (330) is used by the AP to allocate resources and indicate the allocated resources to the STA. The trigger frame is a frame used for uplink frame transmission. For example, the trigger frame may be a frame used to allocate resources to a STA that has sent a PR frame. Here, the resources may be resources for UORA. The AP may indicate the allocated resources to the STA based on information included in the common information field and user information field included in the trigger frame. The AP may allocate resources based on the priority of preempted data. Preempted data includes various types of preempted data. For example, the AP may allocate resources such that high-priority preempted data is transmitted before low-priority preempted data. As another example, the AP may allocate more transmission resources to high-priority preempted data than to low-priority preempted data. Here, the allocated resources may include OFDMA subchannels or subcarriers. In other words, the AP may allocate at least one OFDMA subchannel or subcarrier for transmitting preempted data based on the priority of preempted data.

[0136] In step S1009, the AP receives a frame including at least one preemption data (e.g., Figure 3(Uplink frame 340). Here, the resources indicated by the trigger frame can be used to receive frames including preemption data. The AP can receive frames including preemption data from at least one STA. Different OFDMA subchannels or subcarriers can be used to transmit frames including preemption data for each STA. Frames including preemption data using different OFDMA subchannels or subcarriers can be received simultaneously. Alternatively, frames including preemption data using different OFDMA subchannels or subcarriers can be received at different times. If there is still preemption data to be transmitted by the STA, steps S1007 to S1009 can be repeated. Here, steps S1007 to S1009 can be performed according to priority. For example, steps S1007 to S1009 for frames including high-priority preemption data can be performed first, and steps S1007 to S1009 for frames including low-priority preemption data can be performed after the high-priority preemption data is transmitted.

[0137] Figure 11 A flowchart illustrating a process for a station (STA) to perform a preemption operation according to an embodiment of the present invention is shown. Figure 11 The preemption process is performed by the STAs participating in the preemption operation. For example, an STA could be an STA holding the preemption data. The preemption data could include, for example, low-latency packets (LL packets) and low-latency traffic (LL traffic).

[0138] refer to Figure 11 In step S1101, the STA is based on the initial frame (e.g., Figure 3 The initial frame (300) is used to obtain at least some parameters of the initial frame. The initial frame may be referred to as the first frame. The initial frame includes MU-RTS and RTS. The AID of the user information field of the initial frame can indicate that there is no STA preempting data. The parameters of the initial frame may include the RXVECTOR parameter, and the RXVECTOR parameter may include SCRAMBELR_INITIAL_VALUE.

[0139] In step S1103, the STA acquires a preemption indicator based on a frame including a preemption indicator sent by the AP. For example, the STA can acquire the preemption indicator from at least a portion of the frame including the preemption indicator. For example, the STA can acquire the preemption indicator from the MAC header of the frame including the preemption indicator. As another example, the STA can acquire the preemption indicator from an NFRP trigger frame. For example, an NFRP trigger frame with a feedback type indicating the presence of preemption data can be considered a preemption indicator. That is, an NFRP trigger frame with a feedback type for preemption operation can be considered a preemption indicator. The broadcast AID of the frame including the preemption indicator can include resource allocation information for the subchannel or subcarrier on which the NFRP trigger frame is transmitted. The STA that has acquired the preemption indicator performs channel listening to transmit preemption data. That is, the STA that has acquired the preemption indicator can perform channel listening to perform a preemption operation.

[0140] In step S1105, the STA sends a frame indicating a preemption operation. Here, the frame indicating the preemption operation can be referred to as the second frame. The frame indicating the preemption operation can be a signal, or it can be a PR frame (e.g., Figure 3 S-CTS frame 320) or a signal indicating the presence of preemptive data to be transmitted (e.g., Figure 6c (NDP Feedback Report 621). The frame indicating preemption operation may include the TXVECTOR parameter, and the TXVECTOR parameter includes SCRAMBELR_INITIAL_VALUE. The SCRAMBELR_INITIAL_VALUE of the frame indicating preemption operation has the same value as the SCRAMBELR_INITIAL_VALUE of the initial frame. The STA transmits the frame indicating preemption operation using a subchannel or subcarrier. To perform preemption operation, the STA should use the frame indicating preemption operation to notify the AP of the priority of the preempted data. For this purpose, the STA uses at least one subchannel or at least some subcarriers to transmit the frame indicating preemption operation. Here, the priority of the subchannel or subcarrier that transmits the frame indicating preemption operation indicates the priority of the preempted data. The priority of the subchannel or subcarrier can be determined based on the bandwidth of the subchannel or subcarrier or the priority previously mapped to the subchannel or subcarrier. The priority of the preempted data can be determined by at least one delay limit or QoS parameter.

[0141] In step S1107, the STA receives a trigger frame (e.g., Figure 3The trigger frame (330) is a frame that indicates the resources used by the STA to transmit frames. Here, the resources may be resources for UORA. The STA may identify the allocated resources based on information included in the common information field and user information field included in the trigger frame. Resources may be allocated based on the priority of preempting data. For example, resources may be allocated to preempt high-priority preempted data. As another example, more resources may be allocated for high-priority preempted data. Here, the allocated resources may include OFDMA subchannels or subcarriers. In other words, the allocated resources may include at least a portion of the channels available to the STA.

[0142] In step S1109, the STA sends a frame including preemption data (e.g., Figure 3 The uplink frame 340 can utilize the resources indicated by the trigger frame to transmit a frame including preemptive data. For example, if the trigger frame indicates some subcarriers of the channel, the STA can utilize the indicated subcarriers to transmit a frame including preemptive data. To transmit multiple preemptive data packets with different priorities, steps S1105 to S1107 can be repeated. For example, the STA can transmit preemptive data with "high" priority, and then repeat steps S1107 to S1109 to transmit preemptive data with "normal" priority.

[0143] The operation of the method according to an exemplary embodiment of the present invention can be implemented as a computer-readable program or code in a computer-readable recording medium. The computer-readable recording medium may include all types of recording means for storing data that can be read by a computer system. Furthermore, the computer-readable recording medium can store and execute programs or code that can be distributed across computer systems connected via a network and read in a distributed manner by a computer.

[0144] Additionally, computer-readable recording media may include hardware devices specifically configured to store and execute program commands, such as ROM, RAM, or flash memory. Program commands may include not only machine language code created by a compiler but also high-level language code that can be executed by a computer using an interpreter.

[0145] Although the invention has been described with reference to preferred embodiments thereof, those skilled in the art will understand that various modifications and alterations may be made to the invention without departing from the scope and spirit of the invention as defined by the appended claims.

[0146] Industrial availability This disclosure can be used in devices and recording media in wireless local area network systems.

Claims

1. A method for operating a STA (Station) in a wireless local area network system, the method comprising: Obtain at least some parameters of the first frame based on the first frame; Get the preemption indicator from the second frame, which includes the preemption indicator; The third frame indicating the preemption operation is sent based on the preemption indicator; The fourth frame indicates that the preemption operation has allocated the resources; as well as Data is preempted based on resource delivery. The parameters of the first frame and the parameters of the third frame have the same value.

2. The method according to claim 1, wherein, The third frame is transmitted using at least one subchannel or subcarrier, and At least one subchannel or subcarrier is determined based on the priority of data preemption.

3. The method according to claim 2, wherein, The bandwidth or number of at least one subchannel or subcarrier is determined based on the priority of data preemption.

4. The method according to claim 1, wherein, The third frame includes at least one PR frame, S-CTS frame, or NDP feedback report.

5. The method according to claim 1, wherein, The resources include at least one subchannel or subcarrier and are allocated based on the priority of preempting data.

6. The method according to claim 1, wherein, Frames that include preemption indicators include NDP Feedback Report Polling (NFRP) triggered frames.

7. The method according to claim 6, wherein, NFRP trigger frames are received using resources indicated by the broadcast AID of the frame, which includes a preemption indicator.

8. The method according to claim 6, wherein, The preemption indicator includes an NFRP trigger frame, and The feedback type of the NFRP trigger frame is the type used for preemption operations.

9. The method according to claim 1, wherein, The third frame is a frame sent to a STA that has not preempted data.

10. A method for operating an access point (AP) in a wireless local area network system, the method comprising: Send the first frame; Send the second frame, which includes a preemption indicator; Receive the third frame indicating a preemption operation based on the preemption indicator; Send the fourth frame indicating the resources allocated for the preemption operation; as well as Based on resource reception and preemption data The first frame and the third frame include parameters with the same value.

11. The method according to claim 10, wherein, The second frame is received using at least one subchannel or subcarrier, and At least one subchannel or subcarrier is determined based on the priority of data preemption.

12. The method according to claim 11, wherein, The bandwidth or number of at least one subchannel or subcarrier is determined based on the priority of data preemption.

13. The method of claim 10, wherein: The second frame includes at least one PR frame, S-CTS frame, or NDP feedback report.

14. The method of claim 10, wherein, The resources include at least one subchannel or subcarrier and are allocated based on the priority of preempting data.

15. The method according to claim 10, wherein, The second frame includes the NDP Feedback Report Polling (NFRP) trigger frame.

16. The method according to claim 15, wherein, NFRP trigger frames are received using resources indicated by the broadcast AID of the frame, which includes a preemption indicator.

17. The method according to claim 16, wherein, The preemption indicator includes an NFRP trigger frame, and The feedback type of the NFRP trigger frame is the type used for preemption operations.

18. A station (STA) in a wireless local area network system, the STA comprising: transceiver; as well as The processor, which is connected to the transceiver, The processor is configured as follows: Obtain at least some parameters of the first frame based on the first frame; Get the preemption indicator from the second frame, which includes the preemption indicator; The third frame indicating the preemption operation is sent based on the preemption indicator; The fourth frame indicates that the resource allocated for the preemption operation has been received; and Data is preempted based on resource delivery. The parameters of the first frame and the parameters of the third frame have the same value.

19. An access point (AP) in a wireless local area network system, the AP comprising: transceiver; as well as The processor, which is connected to the transceiver, The processor is configured as follows: Send the first frame; Send the second frame, which includes a preemption indicator; Receive the third frame indicating a preemption operation based on the preemption indicator; Send the fourth frame indicating the resources allocated for the preemption operation; and Based on resource reception and preemption data The first frame and the third frame include parameters with the same value.

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