Low-latency channel access

Abstract

This disclosure provides methods, components, devices, and systems for low-latency channel access. Some aspects relate, in more detail, to the preemption of existing transmit opportunities (TXOPs) such that a device having low-latency traffic to transmit can access the communication medium to transmit the low-latency traffic. Short physical layer protocol data units (PPDUs) may be used in a TXOP having interframe space between PPDUs so that a device having low-latency traffic can transmit preemption instructions in interframe space. A first wireless communication device may identify low-latency traffic during a first PPDU in a TXOP assigned to a second wireless communication device. The first wireless communication device may transmit a preemption instruction in interframe space indicating that subsequent scheduled PPDUs in the TXOP will be preempted so that the first wireless communication device can transmit PPDUs to carry the low-latency traffic.

Description

[Technical Field]

[0001]

[0001] This application claims priority to U.S. Patent Application No. 18 / 450,342, filed on 15 August 2023, entitled “LOW LATENCY CHANNEL ACCESS,” which has been assigned to the assignee of this Specification and is expressly incorporated herein by reference. [Background technology]

[0002]

[0002] A wireless local area network (WLAN) may be formed by one or more wireless access points (APs) that provide a shared wireless communication medium for use by multiple client devices, also known as wireless stations (STAs). The basic building block of a WLAN conforming to the Institute of Electrical and Electronics Engineers (IEEE) 802.11 family of standards is a Basic Service Set (BSS) managed by an AP. Each BSS is identified by a Basic Service Set Identifier (BSSID) advertised by the AP. The AP periodically broadcasts beacon frames to enable any STA within the AP's wireless range to establish or maintain a communication link with the WLAN.

[0003]

[0003] In some WLANs, a transmit opportunity (TXOP) may be assigned to a device, for example, an AP or STA. In some examples, one physical layer protocol data unit (PPDU) may be transmitted per TXOP. In such examples, if another device, such as an STA for an AP TXOP or an AP for an STA TXOP, identifies low-latency traffic for transmission, the other device will wait until the TXOP ends to transmit the low-latency traffic, which may result in a delay in the low-latency data or traffic. [Overview of the Initiative]

[0004]

[0004] Each of the systems, methods, and devices of this disclosure has several innovative aspects, and no single aspect of them alone represents any of the desirable attributes disclosed herein.

[0005]

[0005] One innovative aspect of the subject matter described herein may be implemented in a method for wireless communication by a first wireless communication device. The method may include transmitting a preemption instruction associated with low latency data in the first wireless communication device in the interframe space between the end time of a first physical layer protocol data unit (PPDU) from the second wireless communication device and the scheduled start time for a second PPDU from the second wireless communication device, wherein the first and second PPDUs are scheduled within a TXOP (TXOP) associated with the second wireless communication device, and transmitting a third PPDU that preempts the second PPDU within the TXOP based on the preemption instruction.

[0006]

[0006] Another innovative aspect of the subject matter described herein may be implemented in a first wireless communication device for wireless communication. The first wireless communication device may include a processing system including a processor circuit configuration and a memory circuit configuration for storing code. The processing system causes the first wireless communication device to transmit a preemption instruction associated with low latency data in the first wireless communication device during the interframe space between the end time of a first PPDU from a second wireless communication device and the scheduled start time for a second PPDU from the second wireless communication device, wherein the first and second PPDUs are scheduled within a TXOP associated with the second wireless communication device, and a third PPDU is transmitted based on the preemption instruction, wherein the third PPDU may be configured to preempt the second PPDU within the TXOP.

[0007]

[0007] Another innovative aspect of the subject matter described herein may be implemented in a first wireless communication device for wireless communication. The first wireless communication device may include means for transmitting a preemption instruction associated with low latency data in the first wireless communication device in the interframe space between the end time of a first PPDU from a second wireless communication device and the scheduled start time for a second PPDU from the second wireless communication device, and means for transmitting a third PPDU that preempts the second PPDU in the TXOP, based on the preemption instruction, where the first and second PPDUs are scheduled in a TXOP associated with the second wireless communication device.

[0008]

[0008] Another innovative aspect of the subject matter described herein may be implemented in a non-temporary computer-readable medium for storing code for wireless communication. The code may include instructions executable by a processor to transmit a preemption instruction associated with low latency data in the first wireless communication device in the interframe space between the end time of a first PPDU from the second wireless communication device and the scheduled start time for a second PPDU from the second wireless communication device, wherein the first and second PPDUs are scheduled in a TXOP associated with the second wireless communication device and transmit a third PPDU that preempts the PPDUs based on the preemption instruction.

[0009]

[0009] Some examples of the methods, first wireless communication devices, and non-temporary computer-readable media described herein may further include in the first PPDU an operation, function, means, or command for receiving a preemption permission instruction to a TXOP, wherein the transmission of a preemption instruction may be based on a preemption permission instruction.

[0010]

[0010] Some examples of the methods, first wireless communication devices, and non-temporary computer-readable media described herein may further include operations, functions, means, or instructions for transmitting a response frame to a first PPDU to a second wireless communication device in interframe space, wherein the transmission of a preemption instruction may occur after the transmission of the response frame.

[0011]

[0011] Some examples of the methods, first wireless communication devices, and non-temporary computer-readable media described herein may further include an operation, function, means, or instruction for transmitting a response to the first PPDU within the same frame as the preemption instruction.

[0012]

[0012] Some examples of the methods, first wireless communication devices, and non-temporary computer-readable media described herein may further include in the first PPDU an operation, function, means, or command for receiving instructions from a broadcast resource unit for transmitting a preemption instruction, wherein the preemption instruction may be transmitted via the broadcast resource unit.

[0013]

[0013] Some examples of the methods, first wireless communication devices, and non-temporary computer-readable media described herein may further include operations, functions, means, or commands for receiving a frame from a second wireless communication device in response to a preemption instruction, wherein the transmission of a third PPDU may be in response to the frame.

[0014]

[0014] Some examples of the methods, first wireless communication devices, and non-temporary computer-readable media described herein may further include an action, function, means, or command for performing a listen-before-talk procedure within a time period following the transmission of a preemption instruction, wherein the transmission of a third PPDU may be based on the listen-before-talk procedure, the duration of the time period may be indicated to the first wireless communication device by the second wireless communication device, and the transmission of the third PPDU may be within an permitted duration indicated to the first wireless communication device by the second wireless communication device.

[0015]

[0015] In some examples of the methods, first wireless communication devices, and non-temporary computer-readable media described herein, the listen-before-talk procedure uses subslot granularity to determine the start time of the third PPDU, where the subslots may have a duration of less than 9 microseconds.

[0016]

[0016] In some examples of the methods, first wireless communication devices, and non-temporary computer-readable media described herein, the third PPDU may be transmitted within a time period corresponding to a second interframe space after the transmission of the preemption instruction.

[0017]

[0017] Some examples of the methods, wireless communication devices, and non-temporary computer-readable media described herein may further include operations, functions, means, or instructions for receiving instructions from a second wireless communication device indicating the duration of a second interframe space.

[0018]

[0018] Some examples of the methods, first wireless communication device, and non-temporary computer-readable media described herein may further include an operation, function, means, or command to receive a second preemption instruction from the third wireless communication device in a second interframe space of a TXOP between the end time of the third PPDU and the scheduled start time for receiving the fourth PPDU from the second wireless communication device, wherein the fourth PPDU may be scheduled for reception in the TXOP, and to refrain from monitoring the fourth PPDU based on the second preemption instruction.

[0019]

[0019] Some examples of the methods, first wireless communication devices, and non-temporary computer-readable media described herein may further include operations, functions, means, or commands for receiving a response frame for a third PPDU, including a preemption permission instruction for a TXOP, from a second wireless communication device, wherein the reception of the second preemption instruction may be in response to the preemption permission instruction.

[0020]

[0020] One innovative aspect of the subject matter described herein may be implemented in a method for wireless communication by a second wireless communication device. The method may include receiving a preemption instruction from the first wireless communication device in the interframe space between the end time of a first PPDU from the second wireless communication device and the scheduled start time for a second PPDU from the second wireless communication device, wherein the first and second PPDUs are scheduled in a TXOP associated with the second wireless communication device, and receiving a third PPDU from the first wireless communication device and, based on the preemption instruction, preempting the second PPDU in the TXOP.

[0021]

[0021] Another innovative aspect of the subject matter described herein may be implemented in a second wireless communication device for wireless communication. The second wireless communication device may include a processing system including a processor circuit configuration and a memory circuit configuration for storing code. The processing system may be configured to cause the second wireless communication device to receive a preemption instruction from the first wireless communication device in the interframe space between the end time of a first PPDU from the second wireless communication device and the scheduled start time for a second PPDU from the second wireless communication device, wherein the first and second PPDUs are scheduled in a TXOP associated with the second wireless communication device, and to receive a third PPDU from the first wireless communication device and, based on the preemption instruction, in the TXOP, which preempts the second PPDU.

[0022]

[0022] Another innovative aspect of the subject matter described herein may be implemented in a second wireless communication device for wireless communication. The second wireless communication device may include means for receiving a preemption instruction associated with low latency data in the first wireless communication device from the first wireless communication device in the interframe space between the end time of a first PPDU from the second wireless communication device and the scheduled start time for a second PPDU from the second wireless communication device, wherein the first PPDU and the second PPDU are scheduled in a TXOP associated with the second wireless communication device, and means for receiving a third PPDU from the first wireless communication device and, based on the preemption instruction, preempting the second PPDU in the TXOP.

[0023]

[0023] Another innovative aspect of the subject matter described herein may be implemented in a non-temporary computer-readable medium for storing code for wireless communication. The code may include instructions executable by a processor to receive a preemption instruction from the first wireless communication device in the interframe space between the end time of a first PPDU from the second wireless communication device and the scheduled start time for a second PPDU from the second wireless communication device, where the first and second PPDUs are scheduled in a TXOP associated with the second wireless communication device, and receive a third PPDU from the first wireless communication device and, based on the preemption instruction, preempt the second PPDU in the TXOP.

[0024]

[0024] Some examples of the method, the second wireless communication device, and the non-transitory computer-readable medium described herein may further comprise operations, functions, means, or instructions for transmitting a preemption permission indication for a transmit opportunity (TXOP) in a first physical protocol data unit (PPDU), wherein receiving the preemption indication may be based on the preemption permission indication.

[0025]

[0025] Some examples of the method, the second wireless communication device, and the non-transitory computer-readable medium described herein may further comprise operations, functions, means, or instructions for receiving a response frame to the first PPDU from the first wireless communication device in an inter-frame space, wherein receiving the preemption indication may be after receiving the response frame.

[0026]

[0026] Some examples of the method, the second wireless communication device, and the non-transitory computer-readable medium described herein may further comprise operations, functions, means, or instructions for receiving a response frame to the first PPDU from the first wireless communication device in the same frame as the preemption indication.

[0027]

[0027] Some examples of the method, the second wireless communication device, and the non-transitory computer-readable medium described herein may further comprise operations, functions, means, or instructions for transmitting an indication of a broadcast resource unit for transmission of a preemption indication in the first PPDU, wherein the preemption indication may be received via the broadcast resource unit.

[0028]

[0028] Some examples of the method, the second wireless communication device, and the non-transitory computer-readable medium described herein may further comprise operations, functions, means, or instructions for transmitting a frame in response to the preemption indication, wherein receiving a third PPDU may be responsive to the frame.

[0029]

[0029] In some examples of the methods, second wireless communication devices, and non-temporary computer-readable media described herein, the third PPDU may be received in a time period corresponding to a second interframe space after the reception of the preemption instruction.

[0030]

[0030] Some examples of the methods, second wireless communication devices, and non-temporary computer-readable media described herein may further include operations, functions, means, or instructions for transmitting instructions to the first wireless communication device indicating the duration of a second interframe space.

[0031]

[0031] Some examples of the methods, second wireless communication devices, and non-temporary computer-readable media described herein may further include operations, functions, means, or instructions for receiving a second preemption instruction from the third wireless communication device in the second interframe space of the TXOP between the end time of the third PPDU and the scheduled start time for receiving the fourth PPDU from the second wireless communication device, thereby the fourth PPDU may be scheduled for reception within the TXOP, and receiving a fifth PPDU that preempts the fourth PPDU within the TXOP based on the second preemption instruction from the third wireless communication device.

[0032]

[0032] Some examples of the methods, second wireless communication devices, and non-temporary computer-readable media described herein may further include operations, functions, means, or instructions for transmitting a response frame for a third PPDU including a preemption permission instruction for a TXOP, wherein the reception of the second preemption instruction may be in response to the preemption permission instruction.

[0033]

[0033] Details of one or more implementations of the subject matter described herein are shown in the accompanying drawings and the following description. Other features, embodiments, and advantages will become apparent from the description, drawings, and claims. Note that the relative dimensions in the following figures may not be drawn to exact scale. [Brief explanation of the drawing]

[0034] [Figure 1]

[0034] An illustrative diagram of a wireless communication network is shown. [Figure 2]

[0035] An exemplary protocol data unit (PDU) that can be used for communication between a wireless access point (AP) and one or more wireless stations (STAs) is shown. [Figure 3]

[0036] An exemplary Physical Layer (PHY) Protocol Data Unit (PPDU) that can be used for communication between a wireless AP and one or more wireless STAs is shown. [Figure 4]

[0037] This shows an exemplary PPDU hierarchical format that can be used for communication between a wireless AP and one or more wireless STAs. [Figure 5]

[0038] An example of a Transmit Opportunity (TXOP) timing diagram supporting low-latency channel access is shown. [Figure 6]

[0039] An example of a downlink TXOP timing diagram with a mechanism for triggering uplink transmissions that support low-latency channel access is shown. [Figure 7]

[0040] An example of a downlink TXOP timing diagram with trigger-based preemption of transmits within a TXOP that supports low-latency channel access is shown. [Figure 8]

[0041] An example of a downlink TXOP timing diagram with EDCA-based preemption of transmits within a TXOP that supports low-latency channel access is shown. [Figure 9]

[0042] This shows an example timing diagram for enabling low-latency enhanced distributed channel access (EDCA) during a downlink TXOP with immediate backoff to support low-latency channel access. [Figure 10]

[0043] An example timing diagram for enabling low-latency EDCA during downlink TXOP with immediate backoff to support low-latency channel access is shown. [Figure 11]

[0044] This shows an example timing diagram for enabling low-latency EDCA during uplink TXOP to support low-latency channel access. [Figure 12]

[0045] An example timing diagram for enabling low-latency EDCA during a downlink TXOP that supports low-latency channel access is shown. [Figure 13]

[0046] An example timing diagram for enabling low-latency EDCA during a downlink TXOP that supports low-latency channel access is shown. [Figure 14]

[0047] An example timing diagram for enabling low-latency EDCA during a downlink TXOP that supports low-latency channel access is shown. [Figure 15]

[0048] An example timing diagram is shown, including the AP multicast request mechanism prior to low-latency EDCA authorization, which supports low-latency channel access. [Figure 16]

[0049] This shows an example of a process flow that supports low-latency channel access. [Figure 17]

[0050] A block diagram of an exemplary wireless communication device supporting low-latency channel access is shown. [Figure 18]

[0051] A flowchart is provided illustrating an exemplary process that can be performed by, or in, a first wireless communication device that supports low-latency channel access. [Figure 19]

[0052] A flowchart is provided illustrating an exemplary process that can be performed by, or in, a second wireless communication device that supports low-latency channel access.

[0035]

[0053] Similar reference numbers and names in various drawings refer to the same elements. [Modes for carrying out the invention]

[0036]

[0054] The following description focuses on several specific examples for the purpose of illustrating innovative aspects of the disclosure. However, those skilled in the art will readily recognize that the teachings herein can be applied in numerous different ways. Some or all of the examples described may be implemented in any device, system, or network capable of transmitting and receiving radio frequency (RF) signals in accordance with, among other things, the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard, the IEEE 802.15 standard, the Bluetooth® Special Interest Group (SIG) standard, or one or more of the Long Term Evolution (LTE), 3G, 4G, or 5G (New Radio (NR)) standards issued by the Third Generation Partnership Project (3GPP).The examples described can be implemented in any device, system, or network capable of transmitting and receiving RF signals according to one or more of the following technologies or techniques: code division multiple access (CDMA), time division multiple access (TDMA), orthogonal frequency division multiplexing (OFDM), frequency division multiple access (FDMA), orthogonal FDMA (OFDMA), single-carrier FDMA (SC-FDMA), spatial division multiple access (SDMA), rate-splitting multiple access (RSMA), multi-user shared access (MUSA), single-user (SU) multiple-input multiple-output (MIMO), and multi-user (MU)-MIMO (MU-MIMO). The examples described can also be implemented using other wireless communication protocols or RF signals suitable for use in one or more of the following networks: wireless personal area network (WPAN), wireless local area network (WLAN), wireless wide area network (WWAN), wireless metropolitan area network (WMAN), or Internet of Things (IoT) network.

[0037]

[0055] Various embodiments generally relate to preempting existing transmit opportunities (TXOPs) so that a device with low-latency traffic to transmit can access the communication medium during the TXOP to transmit the low-latency traffic. Some embodiments, more specifically, relate to using relatively short physical layer protocol data units (PPDUs) within a TXOP with interframe space between PPDUs so that a device with low-latency traffic to transmit can transmit a preemption instruction in the interframe space. A short PPDU may refer to a PPDU in a scenario where multiple PPDUs are scheduled within a single TXOP. In some examples, a first wireless communication device, such as an ultra-high reliability (UHR) wireless station (STA) or access point (AP), may identify low-latency traffic in a first PPDU of a TXOP assigned to a second wireless communication device. The first wireless communication device may transmit a preemption instruction in the interframe space (such as a point-coordinated interframe space (PIFS) or short interframe space (SIFS)). A preemption instruction may indicate that subsequent scheduled PPDUs in a TXOP will be preempted in order to allow a first wireless communication device to send a PPDU to carry low-latency traffic. In some examples, the first PPDU may indicate that preemption of a second PPDU is permitted (for example, in the PHY header or receiver address for the preemption instruction).

[0038]

[0056] Certain aspects of the subject matter described herein may be implemented to achieve one or more of the following potential benefits. In some examples, by using short PPDUs within a TXOP, the techniques described may allow other devices to preempt other transmissions within the TXOP in order to transmit low-latency traffic. Enabling preemption of a TXOP in order to transmit low-latency traffic can reduce the time required to transmit low-latency data and thus improve latency. The owner of a TXOP may not be aware that another device has low-latency traffic to transmit, and therefore a preemption instruction may allow a device to indicate that it has low-latency traffic to transmit in order to preempt a PPDU from the TXOP owner. The TXOP owner may, accordingly, delay or postpone the transmission of less urgent traffic that would have been transmitted in the preempted PPDU.

[0039]

[0057] Figure 1 shows a diagram of an exemplary wireless communication network 100. In some embodiments, the wireless communication network 100 may be an embodiment of a wireless local area network (WLAN), such as a Wi-Fi network. For example, the wireless communication network 100 may be a network implementing at least one of the IEEE 802.11 family of wireless communication protocol standards (for example, defined by the IEEE 802.11-2020 specification or its modifications, including but not limited to 802.11ay, 802.11ax, 802.11az, 802.11ba, 802.11bd, 802.11be, 802.11bf, and 802.11bn). In some other examples, the wireless communication network 100 may be an example of a cellular radio access network (RAN), such as a 5G or 6G RAN, implementing one or more cellular protocols, such as those specified in one or more 3GPP standards. In some other examples, the wireless communications network 100 may include WLANs that function in an interoperable or converged manner with one or more cellular RANs to provide larger or extended network coverage to wireless communications devices within the wireless communications network 100, or to enable such devices to connect to the core of a cellular network, for example, to access the network management capabilities and functionality provided by the core of the cellular network.

[0040]

[0058] The wireless communication network 100 may include a number of wireless communication devices, including at least one AP102 and any number of STA104. Although only one AP102 is shown in Figure 1, the wireless communication network 100 may also include multiple AP102s. AP102 may represent or include various different types of network entities, including but not limited to other types of devices or equipment included in a Radio Access Network (RAN), such as home networking APs, enterprise-level APs, single-frequency APs, dual-band simultaneous (DBS) APs, tri-band simultaneous (TBS) APs, standalone APs, non-standalone APs, software-enabled APs (soft APs), and multi-link APs (also referred to as multi-link devices (MLDs)), as well as cellular base stations (such as 3GPP, 4G LTE, 5G, or 6G), or other cellular network nodes such as Node B, evolved Node B (eNB), gNB, transmission reception point (TRP), or Open-RAN (O-RAN) network entities such as central units (CUs), distributed units (DUs), or radio units (RUs).

[0041]

[0059] Each of the STA104 may also be called a mobile station (MS), mobile device, mobile handset, wireless handset, access terminal (AT), user equipment (UE), subscriber station (SS), or subscriber unit, among other examples. STA104 may represent a variety of devices, among other examples, such as mobile phones, other handheld or wearable communication devices, netbooks, notebook computers, tablet computers, laptops, Chromebooks, augmented reality (AR), virtual reality (VR), mixed reality (MR), or augmented reality (XR) wireless headsets or other peripheral devices, wireless earphones, other wearable devices, display devices (such as TVs, computer monitors, or video game consoles), video game controllers, navigation systems, music or other audio or stereo devices, remote control devices, printers, kitchen appliances (including smart refrigerators) or other household appliances, key fobs (such as for passive keyless entry and start (PKES) systems), Internet of Things (IoT) devices, and vehicles.

[0042]

[0060] A single AP102 and associated set of STA104 may be referred to as a basic service set (BSS) managed by each AP102. Figure 1 additionally shows an exemplary coverage area 108 of AP102, which may represent a basic service area (BSA) of a wireless communication network 100. The BSS can be identified by STA104 and other devices by a service set identifier (SSID) and a basic service set identifier (BSSID), which may be the medium access control (MAC) address of AP102. AP102 may periodically broadcast beacon frames ("beacons") containing the BSSID so that any STA104 within AP102's wireless range can "associate" or reassociate with AP102 in order to establish or maintain a communication link 106 (hereinafter also referred to as a "Wi-Fi link") with AP102. For example, a beacon may include identification information or an indicator of the primary channel used by each AP102, and a timing synchronization function (TSF) to establish or maintain timing synchronization with the AP102. The AP102 may provide access to the external network to various STA104 in the wireless communication network 100 via their respective communication links 106.

[0043]

[0061] To establish a communication link 106 with AP102, each STA 104 is configured to perform a passive scan operation or an active scan operation ("scan") on a frequency channel within one or more frequency bands (e.g., 2.4 GHz, 5 GHz, 6 GHz, 45 GHz, or 60 GHz bands). To perform a passive scan, the STA 104 listens for beacons transmitted by each AP102 at periodic time intervals called Target Beacon Transmission Times (TBTTs). To perform an active scan, the STA 104 generates probe requests, transmits them sequentially on each channel to be scanned, and listens for probe responses from AP102. Each STA 104 may perform authentication and association operations to identify, determine, confirm, or select an AP102 to associate with, according to the scan information obtained through the passive or active scan, and to establish a communication link 106 with the selected AP102. The selected AP102 assigns an association identifier (AID) to STA104 upon completion of the association operation, and AP102 uses it to track STA104.

[0044]

[0062] As a result of the increased ubiquity of wireless networks, STA104 may have the opportunity to select one of many BSSs within STA104's range, or to select from multiple AP102s that together form an extended service set (ESS) containing multiple connected BSSs. For example, a wireless communication network 100 may be connected to a wired or wireless distributed system that allows multiple AP102s to be connected within such an ESS. Therefore, STA104 may be covered by two or more AP102s and may associate with different AP102s at different times for different transmissions. In addition, after association with an AP102, STA104 may also periodically scan its vicinity to find a more suitable AP102 to associate with. For example, STA104 moving towards an associated AP102 may perform a “roaming” scan to find another AP102 with more desirable network characteristics, such as a higher received signal strength indicator (RSSI) or reduced traffic load.

[0045]

[0063] In some cases, STA104s can form a network without any other equipment other than AP102s or STA104s themselves. One example of such a network is an ad-hoc network (or wireless ad-hoc network). Ad-hoc networks may alternatively be referred to as mesh networks or peer-to-peer (P2P) networks. In some cases, an ad-hoc network may be implemented within a larger network, such as a wireless communication network 100. In such cases, STA104s may be able to communicate with each other through AP102s using communication link 106, but STA104s may also communicate with each other directly via a direct wireless communication link 110. Additionally, two STA104s may communicate via the direct communication link 110, regardless of whether both STA104s are associated with and serviced by the same AP102. In such an ad-hoc system, it may be assumed that one or more of the STA104s take on the role that is played by AP102s in a BSS. Such an STA104 may be referred to as a group owner (GO) and can coordinate transmissions within an ad-hoc network. Examples of direct wireless communication links 110 include Wi-Fi Direct connections, connections established using Wi-Fi Tunneled Direct Link Setup (TDLS) links, and other P2P group connections.

[0046]

[0064] In some networks, the AP102 or STA104, or both, may support applications associated with high throughput or low latency requirements, or provide lossless audio to one or more other devices. For example, the AP102 or STA104 may support applications and use cases associated with ultra-low latency (ULL), such as ultra-low-latency (ULL) games, or streaming lossless audio and video to one or more personal audio devices (such as peripheral devices) or AR / VR / MR / XR headset devices. In scenarios where a user uses two or more peripheral devices, the AP102 or STA104 may support an extended personal audio network that enables communication with two or more peripheral devices. Furthermore, the AP102 and STA104 may support additional ULL applications, such as cloud-based applications with ULL and high throughput requirements (such as VR cloud games).

[0047]

[0065] As described above, AP102 and STA104 can function and communicate (via their respective communication links 106) in accordance with one or more of the IEEE 802.11 family of wireless communication protocol standards. These standards define WLAN radio protocols and baseband protocols for the physical (PHY) layer and MAC layer. AP102 and STA104 transmit and receive wireless communications (hereinafter also referred to as "Wi-Fi communications" or "wireless packets") between themselves in the form of PHY protocol data units (PPDUs).

[0048]

[0066] Each PPDU is a composite structure containing a PHY preamble and payload in the form of a PHY service data unit (PSDU). Information provided within the preamble can be used by the receiving device to decode subsequent data within the PSDU. In instances where a PPDU is transmitted over bonded or broadband channels, the preamble field is duplicated and may be transmitted on each of multiple component channels. A PHY preamble may contain both a legacy portion (or "legacy preamble") and a non-legacy portion (or "non-legacy preamble"). The legacy preamble may be used for packet detection, automatic gain control, and channel estimation, among other applications. The legacy preamble may also generally be used to maintain compatibility with legacy devices. The format, coding, and information provided within the non-legacy portion of the preamble are associated with a specific IEEE 802.11 wireless communication protocol to be used to transmit the payload.

[0049]

[0067] AP102 and STA104 in the WLAN wireless communication network 100 may transmit PPDUs over unlicensed spectrum, which may be a portion of the spectrum including frequency bands conventionally used by Wi-Fi technology, such as the 2.4 GHz band, 5 GHz band, 6 GHz band, 45 GHz band, and 60 GHz band. Some examples of AP102 and STA104 described herein may also communicate in other frequency bands that may support licensed or unlicensed communication. For example, AP102 or STA104, or both, may also communicate over licensed operating bands, where multiple operators may each have licenses to operate in the same or overlapping frequency ranges. Such license operating bandwidths may correspond to or be associated with the frequency range specifications of FR1 (410 MHz - 7.125 GHz), FR2 (24.25 GHz - 52.6 GHz), FR3 (7.125 GHz - 24.25 GHz), FR4a or FR4-1 (52.6 GHz - 71 GHz), FR4 (52.6 GHz - 114.25 GHz), and FR5 (114.25 GHz - 300 GHz).

[0050]

[0068] Each frequency band may contain multiple subbands and frequency channels (also called subchannels). For example, PPDUs compliant with the IEEE 802.11n, 802.11ac, 802.11ax, 802.11be, and revised 802.11bn standards may be transmitted over one or more of the 2.4GHz, 5GHz, or 6GHz bands, each divided into multiple 20MHz channels. Therefore, these PPDUs are transmitted over physical channels with a minimum bandwidth of 20MHz, but larger channels can also be formed through channel bonding. For example, a PPDU may be transmitted over physical channels with bandwidths of 40MHz, 80MHz, 160MHz, 240MHz, 320MHz, 480MHz, or 640MHz by bonding multiple 20MHz channels together.

[0051]

[0069] In some examples, AP102 or STA104 of a wireless communication network 100 may implement extra-high throughput (EHT) or other features compliant with current and future generations of the IEEE 802.11 family of wireless communication protocol standards (such as modifications to the IEEE 802.11be and 802.11bn standards) to provide additional capabilities that surpass other older systems (such as high-efficiency (HE) systems or other legacy systems). For example, a modification to the IEEE 802.11be standard introduces a 320 MHz channel, which is twice as wide as what is possible with a modification to the IEEE 802.11ax standard. Thus, AP102 or STA104 can use the 320 MHz channel to double the throughput and network capacity and provide rate-versus-range gain at high data rates due to the linear bandwidth-versus-logarithmic SNR tradeoff. EHT and newer wireless communication protocols (such as those referred to as modifications to the IEEE 802.11bn standard or related protocols) can support flexible operating bandwidth extensions, such as wider operating bandwidths compared to legacy operating bandwidths or finer-grained operation compared to legacy operation. For example, an EHT system may enable communication over operating bandwidths of 20 MHz, 40 MHz, 80 MHz, 160 MHz, 240 MHz, and 320 MHz. An EHT system may support multiple bandwidth modes, such as a continuous 240 MHz bandwidth mode, a continuous 320 MHz bandwidth mode, a discontinuous 160+160 MHz bandwidth mode, or a discontinuous 80+80+80+80 (or "4×80") MHz bandwidth mode.

[0052]

[0070] In some examples where a wireless communication device (such as AP102 or STA104) operates in a continuous 320MHz bandwidth mode or a 160+160MHz bandwidth mode, the signal for transmission may be generated by two different transmit chains of the wireless communication device, each having or associated with a 160MHz bandwidth (and each coupled to a different power amplifier). In some other examples, the two transmit chains may be used to support a 240MHz / 160+80MHz bandwidth mode by puncturing the 320MHz / 160+160MHz bandwidth mode with one or more 80MHz subchannels. For example, the signal for transmission may be generated by two different transmit chains of the wireless communication device, each having a 160MHz bandwidth, with one of the transmit chains outputting a signal that has an 80MHz subchannel punctured within it. In some other examples where a wireless communication device can operate in a continuous 240MHz bandwidth mode or a discontinuous 160+80MHz bandwidth mode, the signal for transmission may be generated by three different transmit chains of the wireless communication device, each having an 80MHz bandwidth. In some other examples, the signal for transmission may be generated by four or more different transmission chains of wireless communication devices, each having a bandwidth of 80 MHz.

[0053]

[0071] In discontinuous examples, the operating bandwidth can span one or more heterogeneous sets of subchannels. For example, a 320 MHz bandwidth may be continuous and located within the same 6 GHz band, or it may be discontinuous and located in different bands or regions within a band (e.g., partially within the 5 GHz band and partially within the 6 GHz band).

[0054]

[0072] In some cases, AP102 or STA104 can benefit from operational enhancements associated with EHT and newer generations of the IEEE 802.11 family of wireless communication protocol standards. For example, AP102 or STA104 attempting to access the wireless medium of wireless communication network 100 may implement techniques such as Clear Channel Assessment (CCA) operation based on EHT enhancements, including increased bandwidth, puncturing, or improvements to carrier detection and signal reporting mechanisms (which may include modifications to existing rules, structures, or signaling implemented for legacy systems).

[0055]

[0073] The transmitting and receiving devices AP102 and STA104 may support the use of various modulation and coding schemes (MCSs) for transmitting and receiving data in the wireless communication network 100 to optimally utilize wireless channel conditions, for example, to increase throughput, reduce latency, or impose various quality of service (QoS) parameters. For example, existing technologies (such as the IEEE 802.11ax revised protocol) support the use of up to 1024-QAM, where the modulated symbol carries 10 bits. To further improve the peak data rate, each of AP102 or STA104 may employ the use of 4096-QAM (also called "4k QAM"), which enables the modulated symbol to carry 12 bits. 4k QAM can enable massive peak throughput using the maximum theoretical PHY rate of 10 bps / Hz / subcarrier / spatial stream, which is 23 Gbps (10 bps / Hz / subcarrier / spatial stream) using 5 / 6 LDPC code. * 996 * 4 subcarriers *This is converted to 8 spatial streams / OFDM symbol (13.6 μs). AP102 or STA104 using 4096-QAM allows for a 20% increase in data rate compared to 1024-QAM, assuming the same coding rate, thereby potentially enabling users to achieve higher transmission efficiency.

[0056]

[0074] Figure 2 shows an exemplary protocol data unit (PDU) 200 that can be used for wireless communication between a wireless AP and one or more wireless STAs. For example, the AP and STA may be examples of AP102 and STA104 described with reference to Figure 1. The PDU 200 can be configured as a PPDU. As shown, the PDU 200 includes a PHY preamble 202 and a PHY payload 204. For example, the preamble 202 may include a legacy portion which itself includes a legacy short training field (L-STF) 206 which may consist of two symbols, a legacy long training field (L-LTF) 208 which may consist of two symbols, and a legacy signal field (L-SIG) 210 which may consist of two symbols. The legacy portion of the preamble 202 may be configured according to the IEEE 802.11a wireless communication protocol standard. The preamble 202 may also include a non-legacy portion containing one or more non-legacy fields 212 that conform to, for example, one or more of the IEEE 802.11 family of wireless communication protocol standards.

[0057]

[0075] L-STF206 generally enables receiving devices (such as AP102 or STA104) to perform coarse timing and frequency tracking and automatic gain control (AGC). L-LTF208 generally enables receiving devices to perform fine timing and frequency tracking and also enables initial estimation of the wireless channel. L-SIG210 generally enables receiving devices to determine (acquire, select, identify, detect, verify, calculate, or calculate, etc.) the duration of a PDU to avoid overlapping transmissions with the PDU, and to use the determined duration. The legacy portion of the preamble, including L-STF206, L-LTF208, and L-SIG210, may be modulated according to a binary phase shift keying (BPSK) modulation scheme. The payload 204 may be modulated according to a BPSK modulation scheme, a quadrature BPSK (Q-BPSK) modulation scheme, a quadrature amplitude modulation (QAM) modulation scheme, or another suitable modulation scheme. The payload 204 may include a PSDU containing a data field (DATA) 214, which may carry upper-layer data in the form of, for example, MAC protocol data units (MPDUs) or aggregated MPDUs (A-MPDUs).

[0058]

[0076] Figure 3 shows an exemplary Physical Layer (PHY) Protocol Data Unit (PPDU) 350 that can be used for communication between a wireless AP and one or more wireless STAs. For example, the AP and STA may be examples of AP102 and STA104 described with reference to Figure 1. As shown, the PPDU 350 includes a PHY preamble including a legacy portion 352 and a non-legacy portion 354, and a payload 356 including a data field 374. The legacy portion 352 of the preamble includes an L-STF 358, an L-LTF 360, and an L-SIG 362. The non-legacy portion 354 of the preamble includes a repetition of L-SIG (RL-SIG) 364 and multiple wireless communication protocol version-dependent signal fields following the RL-SIG 364. For example, the non-legacy portion 354 may include a general-purpose signal field 366 (referred to herein as “U-SIG366”) and an EHT signal field 368 (referred to herein as “EHT-SIG368”). The presence of RL-SIG364 and U-SIG366 may indicate to an EHT- or later version-compliant STA104 that PPDU350 is an EHT PPDU, or a PPDU compliant with any later (post-EHT) version of a new wireless communication protocol conforming to a future IEEE 802.11 wireless communication protocol standard. Either or both of U-SIG366 and EHT-SIG368 may be configured as other wireless communication protocol versions associated with revisions of standards in the IEEE family beyond EHT, and may carry version-dependent information about them. For example, U-SIG366 may be used by a receiving device (such as AP102 or STA104) to interpret bits in one or more of EHT-SIG368 or data field 374. In instances involving the use of bonded channels, such as L-STF358, L-LTF360, and L-SIG362, the information in U-SIG366 and EHT-SIG368 may be duplicated and transmitted over each of the 20MHz component channels.

[0059]

[0077] The non-legacy portion 354 further includes an additional short training field 370 (referred herein to as “EHT-STF370”, which may be constructed as other wireless communication protocol versions beyond EHT and carry version-dependent information for them) and one or more additional long training fields 372 (referred herein to as “EHT-LTF372”, which may be constructed as other wireless communication protocol versions beyond EHT and carry version-dependent information for them). The EHT-STF370 may be used for timing and frequency tracking and AGC, and the EHT-LTF372 may be used for more refined channel estimation.

[0060]

[0078] The EHT-SIG368 may be used by AP102 to identify one or more STA104s and to notify the multiple STA104s that AP102 has scheduled uplink (UL) or downlink (DL) resources for them. The EHT-SIG368 may be decoded by each compatible STA104 served by AP102. The EHT-SIG368 may generally be used by a receiving device to interpret bits in the data field 374. For example, the EHT-SIG368 may include resource unit (RU) allocation information, spatial stream configuration information, and user-specific (e.g., STA-specific) signaling information. Each EHT-SIG368 may include a common field and at least one user-specific field. In the context of OFDMA, the common field, in particular among other examples, can indicate the RU distribution across multiple STA104s, the RU allocation in the frequency domain, which RUs are allocated to MU-MIMO transmissions, which RUs respond to OFDMA transmissions, and the number of users in the allocation. The user-specific field is assigned to a specific STA104 and carries STA-specific scheduling information, such as user-specific MCS values ​​and user-specific RU allocation information. Such information allows each STA104 to identify and decode the corresponding RU in the associated data field 374.

[0061]

[0079] Figure 4 shows an exemplary hierarchical format of a PPDU that can be used for communication between a wireless AP and one or more wireless STAs. For example, the AP and STA may be examples of AP102 and STA104 described with reference to Figure 1. As described, each PPDU 400 includes a PHY preamble 402 and a PSDU 404. Each PSDU 404 may represent (or "carry") one or more MAC protocol data units (MPDUs) 416. For example, each PSDU 404 may carry an aggregate MPDU (A-MPDU) 406 containing an aggregation of multiple A-MPDU subframes 408. Each A-MPDU subframe 406 may contain an MPDU frame 410, which includes a MAC delimiter 412 and a MAC header 414 before the accompanying MPDU 416 containing the data portion ("payload" or "frame body") of the MPDU frame 410. Each MPDU frame 410 may also include a frame check sequence (FCS) field 418 for error detection (the FCS field may include a cyclic redundancy check, CRC, etc.) and padding bits 420. An MPDU 416 may carry one or more MAC service data units (MSDUs) 416. For example, an MPDU 416 may carry an aggregate MSDU (A-MSDU) 422 containing multiple A-MSDU subframes 424. Each A-MSDU subframe 424 (represented as an MSDU frame 426) contains a corresponding MSDU 430, preceded by a subframe header 428 and possibly followed by padding bits 432.

[0062]

[0080] Referring again to the MPDU frame 410, the MAC delimiter 412 acts as a marker for the start of the associated MPDU 416 and may indicate the length of the associated MPDU 416. The MAC header 414 may include several fields containing information that defines or indicates the characteristics or attributes of the data encapsulated within the frame body 416. The MAC header 414 may include a duration field indicating the duration from the end of the PPDU to the end of the acknowledgment (ACK) or block ACK (BA) of the PPDU that will be transmitted by the receiving wireless communication device. The use of the duration field helps reserve the wireless medium for the indicated duration, allowing the receiving device to establish its network allocation vector (NAV). The MAC header 414 also includes one or more fields indicating the addresses of the data encapsulated within the frame body 416. For example, the MAC header 414 may include a source address, transmitter address, receiver address, or a combination of destination addresses. The MAC header 414 may further include a frame control field containing control information. The frame control field may specify the frame type, such as a data frame, control frame, or management frame.

[0063]

[0081] Access to a shared wireless medium is generally managed by a distributed coordination function (DCF). When a DCF is present, there is generally no centralized master device allocating the time and frequency resources of the shared wireless medium. Conversely, wireless communication devices such as AP102 or STA104 may wait for a certain period of time before being permitted to transmit data, and then compete for access to the wireless medium. The DCF is implemented using time intervals (slot time, or "slot interval") and interframe space (IFS). The IFS provides preferential access to control frames used for proper network operation. Transmission can be initiated at slot boundaries. Various types of IFS exist, including short IFS (SIFS), distributed IFS (DIFS), extended IFS (EIFS), and arbitration IFS (AIFS). The values ​​of slot time and IFS may be provided by appropriate standard specifications, such as one or more of the IEEE 802.11 family of wireless communication protocol standards.

[0064]

[0082] In some cases, wireless communication devices (such as AP102 or STA104) may implement DCF by using carrier sense multiple access (CSMA) / collision avoidance (CA) (CSMA / CA) techniques. According to such techniques, before transmitting data, the wireless communication device may perform a clear channel assessment (CCA) to determine (identify, detect, confirm, calculate, or compute) whether the relevant wireless channel is idle. CCA includes both physical (PHY level) carrier detection and virtual (MAC level) carrier detection. Physical carrier detection is achieved by measuring the received signal strength of a valid frame, which is then compared to a threshold to determine (identify, detect, confirm, calculate, or compute) whether the channel is busy. For example, if the received signal strength of the detected preamble exceeds the threshold, the medium is considered busy. Physical carrier detection also includes energy detection. Energy detection involves measuring the total energy received by the wireless communication device, regardless of whether the received signal represents a valid frame. If the detected total energy exceeds the threshold, the medium is considered busy.

[0065]

[0083] Virtual carrier detection is achieved using a Network Allocation Vector (NAV), which effectively functions as the time elapsed before a wireless communication device competes for access, even if no symbols are detected or if the detected energy falls below a relevant threshold. The NAV is reset each time a valid frame not addressed to the wireless communication device is received. When the NAV reaches 0, the wireless communication device performs physical carrier detection. If the channel remains idle for a suitable IFS, the wireless communication device invokes a backoff timer, which represents the duration for which the device detects an idle medium before being allowed to transmit. If the channel remains idle until the backoff timer expires, the wireless communication device becomes the holder (or "owner") of a transmit opportunity (TXOP) and may begin transmitting. The TXOP is the length of time a wireless communication device can transmit a frame over the channel after a "winning" competition for the wireless medium. The TXOP duration may be indicated in the U-SIG field of the PPDU. On the other hand, if one or more of the carrier sense mechanisms indicate that the channel is busy, the MAC controller in the wireless communication device will not allow transmission.

[0066]

[0084] Each time a wireless communication device generates a new PPDU for transmission with a new TXOP, it randomly selects a new backoff timer duration. The available distribution of the number of durations that can be randomly selected for the backoff timer is called the contention window (CW). There are different CW and TXOP times for each of the four access categories (ACs): voice (AC_VO), video (AC_VI), background (AC_BK), and best-effort (AC_BE). This allows for prioritizing certain types of traffic within the network.

[0067]

[0085] In some other examples, wireless communication devices (such as AP102 or STA104) may compete for access to the wireless medium of WLAN100 following an Extended Distributed Channel Access (EDCA) procedure. Random channel access mechanisms such as EDCA can give high-priority traffic a greater chance of gaining medium access than low-priority traffic. Wireless communication devices using EDCA may categorize data into different access categories. Each AC may be associated with a different priority level and may be assigned different ranges of RBOs so that higher-priority data is more likely to win TXOP than lower-priority data (for example, by assigning lower random backoffs (RBOs) to higher-priority data and higher RBOs to lower-priority data). While EDCA increases the chances that low-latency data traffic will access the shared wireless medium during a given competition period, the unpredictable consequences of medium access competition behavior can prevent low-latency applications from achieving a certain level of throughput or meeting certain latency requirements.

[0068]

[0086] Some APs and STAs (such as AP102 and STA104, as described with reference to Figure 1) can implement spatial reuse techniques. For example, AP102 and STA104 configured for communication using protocols defined in modifications of the IEEE 802.11ax or 802.11be standards may be configured with BSS colors. AP102s associated with different BSSs may be associated with different BSS colors. The BSS color is a numerical identifier (such as a 6-bit field carried by the SIG field) for each BSS of AP102'. Each STA104 may learn its own BSS color when associated with its respective AP102. BSS color information is communicated in both the PHY and MAC sublayers. If AP102 or STA104 detects, acquires, selects, or identifies a wireless packet from another wireless communication device while competing for access, AP102 or STA104 may apply different competition parameters depending on whether the wireless packet is being transmitted by another wireless communication device (such as another AP102 or STA104) within its BSS, or to a wireless communication device from an overlapping BSS (OBSS), as determined, identified, confirmed, or calculated by the BSS color index in the wireless packet's preamble. For example, if the BSS color associated with the wireless packet is the same as the BSS color of AP102 or STA104, AP102 or STA104 may use a first RSSI detection threshold when performing a CCA on the wireless channel. However, if the BSS color associated with a wireless packet differs from the BSS color of AP102 or STA104, AP102 or STA104 may use a second RSSI detection threshold instead of a first RSSI detection threshold when performing a CCA on the wireless channel, and the second RSSI detection threshold is greater than the first RSSI detection threshold. In this way, the criteria for winning the conflict are relaxed when an interfering transmission is associated with an OBSS.

[0069]

[0087] Some APs and STAs (such as AP102 and STA104, as described with reference to Figure 1) may implement techniques for spatial reuse involving participation in a cooperative communication scheme. According to such techniques, AP102 may compete for access to the wireless medium in order to gain control of the medium for the TXOP. The AP that wins the competition (hereinafter also referred to as the “shared AP”) may select one or more other APs (hereinafter also referred to as “shared APs”) to share the resources of the TXOP. The shared APs and shared APs may be located in close proximity to each other such that at least some of their wireless coverage areas overlap at least partially. Some examples may specifically involve cooperative AP TDMA or OFDMA techniques for sharing the time or frequency resources of the TXOP. To share those time or frequency resources, the shared AP may divide the TXOP into multiple time or frequency segments, each containing a time or frequency resource representing a portion of the TXOP. The shared AP may assign the time or frequency segments to itself or to one or more of the shared APs. For example, each shared AP may utilize a partial TXOP allocated by the shared AP for its uplink or downlink communication with its associated STA.

[0070]

[0088] In some examples of such TDMA techniques, each part of the TXOP contains a set of time resources that do not overlap with any time resources of any other part of the TXOP. In such examples, scheduling information may include indices of time resources among the TXOP's time resources, associated with each part of the TXOP. For example, scheduling information may include indices of time segments of the TXOP, such as indices of one or more sets of slots or symbolic periods associated with each part of the TXOP, for example, for multi-user TDMA.

[0071]

[0089] In some examples of OFDMA techniques, each part of the TXOP contains a set of frequency resources that do not overlap with any other frequency resources of any other part of the TXOP. In such examples, scheduling information may include an index of frequency resources among the TXOP's frequency resources, associated with each part of the TXOP. For example, scheduling information may include an index of bandwidth portions of wireless channels, such as an index of one or more subchannels or RUs associated with each part of the TXOP, for example, for multi-user OFDMA.

[0072]

[0090] In this way, acquisition of a TXOP by a shared AP enables communication between one or more additional shared APs and their respective BSSs, provided that appropriate power control and link adaptation are in place. For example, a shared AP may limit the transmit power of a selected shared AP so that interference from the selected AP does not prevent the STA associated with the TXOP owner from successfully decoding packets transmitted by the shared AP. Other APs may not have to wait to win a competition for the TXOP in order to transmit and receive data according to normal CSMA / CA or Extended Distributed Channel Access (EDCA) techniques, so such techniques can be used to reduce latency. Additionally, by enabling a group of APs associated with different BSSs to participate in a cooperative AP transmit session, during which the group of APs may share at least a portion of a single TXOP acquired by any one of the participating APs, such techniques can increase throughput across the BSSs associated with the participating APs and achieve improved throughput fairness. Furthermore, by appropriately selecting shared APs and scheduling their respective time or frequency resources, medium utilization can be maximized or increased, while packet loss resulting from OBSS interference can be minimized or reduced. Various implementations can achieve these and other benefits without requiring shared APs or shared APs to be aware of STA104s associated with other BSSs, without requiring pre-allocated or dedicated master APs or groups of pre-allocated APs, and without requiring backhaul coordination between APs participating in TXOP.

[0073]

[0091] In some cases, where the signal strength or interference level associated with the selected AP is relatively low (e.g., below a given value), or where the decoding error rate of the selected AP is relatively low (e.g., below a threshold), the start times of communication between different BSSs may be synchronized. Conversely, if the signal strength or interference level associated with the selected AP is relatively high (e.g., above a given value), or where the decoding error rate of the selected AP is relatively high (e.g., above a threshold), the start times may be offset from each other by the time associated with decoding the preamble of the wireless packet and determining from the decoded preamble whether the wireless packet is an in-BSS packet or an OBSS packet. For example, the time between the transmission of an in-BSS packet and the transmission of an OBSS packet may allow each AP (or its associated STAs) to decode the preamble of the wireless packet, obtain the BSS color value carried within the wireless packet, and determine whether the wireless packet is an in-BSS packet or an OBSS packet. In this way, each of the participating APs and their associated STAs may be able to receive and decode in-BSS packets in the presence of OBSS interference.

[0074]

[0092] In some examples, a shared AP may poll a set of unmanaged or unco-managed APs that support coordinated reuse to identify candidates for future space reuse opportunities. For example, a shared AP may send one or more space reuse polling frames as part of determining one or more space reuse criteria and selecting one or more other APs to become a shared AP. Following the polling, the shared AP may receive responses from one or more of the polled APs. In some specific examples, a shared AP may send coordinated AP TXOP indication (CTI) frames to other APs indicating the time and frequency of the TXOP resources that may be shared. The shared AP may select one or more candidate APs when it receives coordinated AP TXOP request (CTR) frames from each candidate AP indicating their willingness to participate in the TXOP. Polling responses or CTR frames may include power indications, such as received (RX) power or RSSI measured by each AP. In some other examples, a shared AP may directly measure potential interference between services supported by one or more APs (such as UL transmissions) and select shared APs based on the measured potential interference. Generally, a shared AP selects APs to participate in the collaborative space reuse while still protecting their own transmissions (sometimes called primary transmissions) between STAs within its BSS. Resources may then be allocated to the selected APs during the TXOP as described above.

[0075]

[0093] Retransmission protocols such as hybrid automatic repeat request (HARQ) can also provide performance gains. The HARQ protocol can support various HARQ signaling between transmitting and receiving wireless communication devices (such as AP102 and STA104, as described with reference to Figure 1) to improve retransmission operation in a WLAN, as well as signaling between the PHY layer and the MAC layer. HARQ uses a combination of error detection and error correction. For example, a HARQ transmission may include error-check bits added to the data to be transmitted using error-detecting (ED) codes such as cyclic redundancy check (CRC). These error-check bits can be used by the receiving device to determine whether the received HARQ transmission has been properly decoded. In some embodiments, the original data to be transmitted (information bits) may be encoded with forward error correction (FEC) codes, such as using a low-density parity check (LDPC) coding scheme that systematically encodes the information bits to generate parity bits. The transmitting device may send both the original information bits and the parity bits to the receiving device in a HARQ transmission. The receiving device may use the parity bits to correct errors in the information bits and thus avoid retransmission.

[0076]

[0094] Implementing the HARQ protocol in a WLAN can improve the reliability of data communicated from a transmitting device to a receiving device. The HARQ protocol can support the establishment of a HARQ session between two devices. Once a HARQ session is established, if the receiving device is unable to properly decode (and correct errors in) a first HARQ transmission received from the transmitting device, the receiving device may send a HARQ feedback message to the transmitting device (such as a Negative Response (NACK)) indicating that at least a portion of the first HARQ transmission was not properly decoded. Such a HARQ feedback message may differ from the conventional block ACK feedback message type associated with normal ARQ. In response to receiving the HARQ feedback message, the transmitting device may send a second HARQ transmission to the receiving device to communicate at least a portion that will further assist the receiving device in decode the first HARQ transmission. For example, the transmitting device may include some or all of the original information bits, some or all of the original parity bits, and other different parity bits in the second HARQ transmission. The combined HARQ transmissions can be processed for decoding and error correction so that the complete signal associated with the HARQ transmission can be obtained.

[0077]

[0095] In some embodiments, the receiving device may be enabled to control whether to continue the HARQ process or revert to a non-HARQ retransmission scheme (such as the Automatic Retransmission Request (ARQ) protocol). Such switching can reduce feedback overhead and increase flexibility for retransmission by allowing the device to dynamically switch between the ARQ protocol and the HARQ protocol during frame exchange. Some implementations may also allow multiplexing of communications employing ARQ with communications employing HARQ.

[0078]

[0096] In some implementations, the AP102 and STA104 can support various multi-user communications. Specifically, they can support simultaneous transmission from one device to multiple devices (such as multiple simultaneous downlink communications from the AP102 to the corresponding STA104), or simultaneous transmission from multiple devices to a single device (such as multiple simultaneous uplink transmissions from the corresponding STA104 to the AP102). As an example, in addition to MU-MIMO, the AP102 and STA104 may support OFDMA. OFDMA is, in some forms, a multi-user version of OFDM.

[0079]

[0097] In OFDMA, the available frequency spectrum of a wireless channel can be divided into multiple RUs, each containing multiple frequency subcarriers (also called "tones"). Different RUs can be allocated or assigned by AP102 to different STA104 at a given time. The size and distribution of RUs can be referred to as RU allocation. In some examples, RUs may be allocated at 2MHz intervals, so the smallest RU may contain 26 tones, consisting of 24 data tones and 2 pilot tones. As a result, a 20MHz channel can have up to 9 RUs allocated (such as 2MHz, 26-tone RUs), as some tones are reserved for other purposes. Similarly, a 160MHz channel can have up to 74 RUs allocated. Other tonal RUs can also be allocated, such as 52-tone, 106-tone, 242-tone, 484-tone, and 996-tone RUs. Adjacent RUs may be separated by null subcarriers (such as DC subcarriers) for purposes such as reducing interference between adjacent RUs, reducing the receiver's DC offset, and avoiding transmission center frequency leakage.

[0080]

[0098] In the case of UL MU transmission, AP102 may send a trigger frame to initiate and synchronize UL OFDMA or UL MU-MIMO transmissions from multiple STA104 to AP102. Thus, such a trigger frame may enable multiple STA104 to transmit UL traffic to AP102 simultaneously. The trigger frame may address one or more STA104 through their respective association identifiers (AIDs), and each AID (and therefore each STA104) may be assigned one or more RUs that can be used to transmit UL traffic to AP102. AP may also designate one or more random access (RA) RUs that unscheduled STA104s may compete for.

[0081]

[0099] In some wireless communication systems, AP102 may allocate or assign multiple RUs to a single STA104 in OFDMA transmission (hereinafter also known as "multi-RU aggregation"). Multi-RU aggregation, which facilitates puncturing and scheduling flexibility, can ultimately reduce latency. As increased bandwidth is supported by new standards (such as the IEEE 802.11be standard amendment supporting 320 MHz, and the IEEE 802.11bn standard amendment supporting 480 MHz and 640 MHz), various combinations of multiple RUs (multi-RUs) may exist. Values ​​indicating various multi-RU combinations may be provided by the appropriate standards specification (for example, one or more of the IEEE 802.11 family of wireless communication protocol standards, including the 802.11be standard amendment).

[0082]

[0100] Since Wi-Fi is not the only technology operating in the 6GHz band, using multiple RUs with channel puncturing can enable the use of larger bandwidths, allowing for high throughput while avoiding transmission on locally unauthorized frequencies due to incumbent operation. Puncture can be used with multi-RU transmissions to enable the establishment of wide channels using discontinuous spectral blocks. In such examples, the portion of the bandwidth between two RUs allocated to a particular STA104 can be punctured. Thus, spectral efficiency and flexibility can be improved.

[0083]

[0101] As mentioned above, STA-specific RU assignment information may be included in the signaling field of the PPDU preamble (such as the EHT-SIG field of an EHT PPDU). Preamble puncturing can enable wider bandwidth transmission for increased throughput and spectral efficiency in the presence of interference from current technology and other wireless communication devices. Since RUs can be assigned individually in MU PPDUs, the use of the MU PPDU format can indicate preamble puncturing for SU transmissions. While puncturing in the amendment to the IEEE 802.11ax standard was limited to OFDMA transmissions, the amendment to the IEEE 802.11be standard extended puncturing to SU transmissions. In some examples, RU assignment information in a common field of EHT-SIG can be used to assign RUs individually to a single user, thereby avoiding punctured channels. In some other examples, U-SIG may be used to indicate SU preamble puncturing. For example, SU preamble puncturing may be indicated by the value of the EHT-SIG compression field within U-SIG.

[0084]

[0102] In certain environments, locations, or conditions, regulatory bodies may impose power spectral density (PSD) limits on one or more communication channels or on an entire band (such as the 6 GHz band). PSD is a measure of transmit power as a function of unit bandwidth (such as per 1 MHz). The total transmit power of a transmission is consequently the product of the PSD and the total bandwidth through which the transmission is carried. Unlike the 2.4 GHz and 5 GHz bands, the United States Federal Communications Commission (FCC) has established PSD limits for low-power devices when operating in the 6 GHz band. The FCC defines three power classes for operation in the 6 GHz band: standard power, low-power indoor, and very low power. Some AP102 and STA104 units operating in the 6GHz band may comply with the Low Power Indoor (LPI) power class, which limits the transmit power of the AP102 and STA104 to 5 decibel milliwatts per megahertz (dBm / MHz) and -1 dBm / MHz, respectively. In other words, transmit power in the 6GHz band is PSD limited per MHz.

[0085]

[0103] Such PSD limitations can undesirably reduce the transmit range, decrease packet discovery capability, and reduce the channel estimation capability of AP102 and STA104. In some examples where transmission is PSD limited, AP102 or STA104 of wireless communication network WLAN 100 may transmit over a larger transmit bandwidth to allow for an increase in total transmit power, which can increase the SNR and extend the coverage of wireless communication devices. For example, to overcome or extend PSD limitations and improve SNR for low-power devices operating in the PSD-limited bandwidth, 802.11be introduced a duplication (DUP) mode for transmission, where data in the payload portion of a PPDU is modulated for transmission on a “base” frequency subband, such as the first RU of an OFDMA transmission, and copied (e.g., duplicated) to another frequency subband, such as the second RU of an OFDMA transmission. In DUP mode, two copies of the data are transmitted, and dual-carrier modulation (DCM) is used, which also has the effect of copying the data so that two copies of the data are carried by each of the duplicate RUs, resulting in, for example, four copies of the data being transmitted. The data rate for transmitting each copy of user data using DUP mode may be the same as the data rate for transmission using "normal" mode, but the transmit power for transmission using DUP mode can be essentially multiplied by the number of copies of the data being transmitted, at the cost of requiring increased bandwidth. Thus, using DUP mode can extend the range but reduce spectral efficiency.

[0086]

[0104] In some other instances where transmission is subject to PSD limitations, distributed tone mapping operation may be used to increase the bandwidth for STA104 to transmit uplink communication to AP102. As used herein, the term “distributed transmission” refers to PPDU transmission over discontinuous tones (or subcarriers) of a wireless channel. In contrast, the term “continuous transmission” refers to PPDU transmission over continuous tones. As used herein, a logical RU represents the number of tones or subcarriers allocated to a given STA104 for PPDU transmission. As used herein, a “normal RU” (or rRU) refers to any non-distributed RU or MRU tone plan, such as configurations supported by 802.11be or earlier versions of the IEEE 802.11 family of wireless communication protocol standards. As used herein, a “distributed RU” (or dRU) refers to a tone distributed across a set of discontinuous subcarrier indices to which a logical RU is mapped. The term “distributed tone plan” refers to the set of discontinuous subcarrier indices associated with a dRU. The channel or portion of a channel in which dispersed tones are scattered is called the spread bandwidth, and the spread bandwidth can be, for example, 40 MHz, 80 MHz, or higher. The use of dRU may be limited to uplink communications because the benefit of addressing the PSD limit may only exist for uplink communications.

[0087]

[0105] Several wireless devices, such as STA104 and AP102, may implement UHR. UHR may include low-latency channel access extensions to improve latency for event-driven traffic use cases. Two potential extension scenarios include preemption within TXOP for downlink event-driven and / or aperiodic low-latency traffic, and preemption within TXOP for uplink event-driven and / or aperiodic low-latency traffic. For event-driven low-latency data, an STA104 with low-latency event-driven traffic may not be the TXOP owner or responder, and therefore such an STA104 would wait for the current TXOP owner to terminate its transmission. For low-latency event-driven uplink traffic, AP102 does not know which non-AP STA104 has such low-latency traffic in its queue, or what the size of such low-latency traffic is.

[0088]

[0106] STA104 and AP102 may use the techniques described herein to preempt a TXOP for transmitting low-latency traffic. For example, a TXOP may be scheduled using interframe space between PPDUs so that a device having low-latency traffic to transmit can send a preemption instruction during interframe space. Low-latency traffic is sometimes referred to as latency-sensitive traffic. In some examples, a first wireless communication device, such as UHR STA104 or AP102, may identify low-latency traffic during a first PPDU of a TXOP assigned to a second wireless communication device. The first wireless communication device may send a preemption instruction in interframe space (such as PIFS or SIFS) indicating that subsequent scheduled PPDUs in the TXOP will be preempted so that the first wireless communication device can transmit a PPDU to carry the low-latency traffic.

[0089]

[0107] Figure 5 shows an example of a TXOP timing diagram 500 that supports low-latency channel access. The TXOP timing diagram 500 implements, or can implement, an embodiment of the wireless communication network 100.

[0090]

[0108] The first exemplary TXOP timing diagram 502 shows a downlink low-latency event-driven traffic scenario. The second exemplary TXOP timing diagram 504 shows an exemplary uplink low-latency event-driven traffic scenario.

[0091]

[0109] In the first exemplary TXOP timing diagram 502, AP102 may be the TXOP owner for the first TXOP 506. AP102 may transmit a long downlink PPDU 510 in the first TXOP 506, where a long PPDU refers to a scenario in which only one PPDU is transmitted within the TXOP, as in the case of the first TXOP 506. STA104, receiving the long downlink PPDU 510, may transmit an acknowledgment 512 for the long downlink PPDU 510 within the first TXOP 506. The “Ack” shown in Figures 5 to 11 may refer to the ACK as described herein. While the long downlink PPDU 510 is being transmitted, a new downlink low latency packet may arrive at AP102 for transmission (labeled “DL Low Lat Traffic Arrival” in Figure 502). AP102 waits until the second TXOP508 to transmit a downlink low-latency packet in PPDU514 (labeled "Low Lat PPDU" in Figure 502). STA104 may send an acknowledgment 516 to PPDU514 within the second TXOP508. The second TXOP508 may be a low-latency TXOP, and PPDU514 may be a low-latency PPDU. As shown, AP102 waits until the second TXOP508 to transmit the low-latency downlink packet, which may delay the transmission of the low-latency packet. The time to transmit the low-latency packet can be reduced by shortening the PPDU. For example, AP102 may use EDCA parameters such as the MU EDCA parameter to control the TXOP limit in cases where the AP is not the TXOP owner. As another example, AP102 may use other potential EDCA parameter set variations.

[0092]

[0110] In the second exemplary TXOP timing diagram 504, AP102 may be the TXOP owner for the first TXOP 506. AP102 may transmit a long downlink PPDU 510 in the first TXOP 506. STA104, receiving the long downlink PPDU 510, may transmit an acknowledgment 512 for the long downlink PPDU 510 within the first TXOP 506. While transmitting the long downlink PPDU 510, a new uplink low latency packet may arrive at STA104 for transmission to AP102 (indicated as "UL low latency traffic arrival" in Figure 504). STA104 waits for the second TXOP 518 assigned to STA104 to transmit the uplink low latency packet in PPDU 520. AP102 may transmit an acknowledgment 522 for PPDU 520 within the second TXOP 518. The second TXOP518 may be a low-latency TXOP, and the PPDU520 may be a low-latency PPDU (labeled "Low Lat PPDU" in Figure 502). As shown in the illustration, STA104 waits to transmit low-latency uplink packets to the second TXOP518, which may delay the transmission of low-latency packets. The techniques described herein may be used to reduce the waiting time for transmitting low-latency uplink and downlink packets for a device during a TXOP. For example, a device that is not the TXOP owner may use the techniques described to transmit low-latency traffic arriving during a TXOP, or the TXOP owner may use the techniques described to transmit low-latency traffic arriving at the TXOP owner during a TXOP.

[0093]

[0111] Figure 6 shows an example of a downlink TXOP timing diagram with a mechanism for triggering an uplink transmit 600 that supports low-latency channel access. A downlink TXOP timing diagram with a mechanism for triggering an uplink transmit 600 can, or may be, implement an embodiment of the wireless communication network 100.

[0094]

[0112] As shown in Figure 6, the downlink TXOP 602 may be assigned to AP 102. Multiple short PPDUs (such as the first downlink PPDU 604 labeled "DL PPDU1" in Figure 6, and the second downlink PPDU 612 labeled "DL PPDU2" in Figure 6) may be scheduled in the downlink TXOP 602. STA 104 may receive the first downlink PPDU 604 and send an acknowledgment 606 for the first downlink PPDU 604 within the downlink TXOP 602, and / or STA 104 may receive the second downlink PPDU 612 and send an acknowledgment 614 for the first downlink PPDU 604 within the downlink TXOP 602. AP102 and STA104 may, for example, execute an uplink initiation mechanism 610 (labeled “UL initiation mechanism”) in the interframe space between a first downlink PPDU 604 and a second downlink PPDU 612, if STA104 identifies low-latency uplink traffic for transmission within downlink TXOP 602. For example, STA104 may send a preemption instruction to preempt the second downlink PPDU 612. In some examples, the first downlink PPDU 604 may include an instruction that preemption is permitted or enabled. In some examples, preemption may be dynamically enabled and disabled through UHR management signaling.

[0095]

[0113] Preemption within a TXOP, as described herein, can improve WLAN reliability in terms of latency by allowing low-latency devices (such as AP102 or STA104) with event-driven low-latency traffic to preempt an existing TXOP acquired by another TXOP owner (such as based on a preemption permission or enablement instruction from the TXOP owner) to access the transmission medium earlier to send low-latency traffic. At a high level, preemption techniques may involve a TXOP owner (such as AP102 or STA104) using short PPDUs with inter-frame space isolation (such as PIFS or SIFS) between PPDUs to allow devices with low-latency traffic to access the channel within the TXOP and avoid additional competition with other devices. Preemption techniques can be scalable, allowing several low-latency STA104s to benefit from low-latency channel access while avoiding increased collisions between overlapping BSSs without incurring high complexity. The possibility of authorizing a preemption instruction by the TXOP owner can occur early in the PPDU, and a preemption instruction or request by a device with low-latency traffic to transmit may be as simple as an instruction indicating the presence of pending low-latency traffic.

[0096]

[0114] Some examples of preemption within TXOPs can be trigger-based. For example, 802.11ax introduced uplink OFDMA-based random backoff (UORA) for trigger-based random access, and null data pack (NDP) feedback reporting poles (NFRP) / NDP feedback reports (NFRs) and buffer status reporting poles (BSRP) / buffer status reports (BSRs) for collecting feedback. UORA, NFRP / NFR, or BSRP / BSR techniques can be used for trigger-based preemption of transmissions with TXOPs. UORA can introduce uncertainty regarding whether transmissions from client devices will collide on RUs and APs, and regarding the amount of RUs that should be scheduled without aperiodic client traffic. In some examples, the TXOP owner (e.g., AP102) may use short PPDUs separated in interframe space and send a preemption permission instruction. Based on the preemption permission instruction, a non-TXOP owner device with low-latency traffic to transmit, such as STA104, can send a preemption instruction to the TXOP owner. In response to a preemption instruction, the TXOP owner can send a trigger frame (e.g., an NFRP, BSRP, or basic trigger frame) to trigger a non-TXOP owner device to send low-latency data directly or to allocate a random RU that may be reserved by the non-TXOP owner device.

[0097]

[0115] In some cases, an STA104 with low-latency traffic may notify AP102 of its traffic requirements, which may require preemption support from AP102. The TXOP owner (e.g., AP102) can enable or allow preemption by setting the preemption enable bit in the PPDU sent by the TXOP owner to "1". An STA104 with low-latency traffic may also notify AP102 of additional parameters, such as mean inter-packet / burst arrival or data rate, through management frames such as Stream Classification Service (SCS) request responses.

[0098]

[0116] In some cases, client devices such as STA104 may not be able to set up block acknowledgments to send multiple MPDUs before preempting AP102, and therefore STA104 may be allowed to send multiple PPDUs to AP102 within specified limits.

[0099]

[0117] In some cases, client devices such as the STA104 may be able to send preemption instructions to the TXOP owner without competing for media access, based on regulatory rules that allow short packets to be sent.

[0100]

[0118] Some examples of preemption within TXOP can be EDCA-based. EDCA-based methods may use SU transmissions, which may be defined in UHR. In EDCA-based methods, client devices may select transmission parameters based on buffered event-driven low-latency traffic.

[0101]

[0119] Figure 7 shows an example of a downlink TXOP timing diagram 700 with trigger-based preemption of transmits within a TXOP to support low-latency channel access. The downlink TXOP timing diagram 700 with trigger-based preemption of transmits within a TXOP can, or may, implement an embodiment of the wireless communication network 100.

[0102]

[0120] The first exemplary TXOP timing diagram 702 shows an example of implementing NFRP-based trigger-based preemption for transmission for TXOP 706 assigned to AP102. The second exemplary TXOP timing diagram 704 shows an example of implementing UORA-based trigger-based preemption for transmission for TXOP 706 assigned to AP102.

[0103]

[0121] In the first exemplary TXOP timing diagram 702, AP102 may transmit a first downlink PPDU 708 (labeled "DL PPDU1+NFRP" in Figure 702), which also includes NFRP. In response to the first downlink PPDU 708, STA104, which receives the first downlink PPDU 708, may transmit an acknowledgment 710 for the first downlink PPDU 708. Any STA104 that has low-latency data to transmit may also transmit an NFR 712 indicating that the STA has low-latency data to transmit. In response to an NFR(s) 712, AP102 may transmit a trigger frame 714 that indicates to STA104 to transmit uplink low-latency data within TXOP 706 and / or may indicate resources for STA104. STA(s) 104 may transmit a trigger-based PPDU 716 containing each uplink low-latency data (labeled "TB-PPDU:UL LL data") triggered by the trigger frame 714. For example, if three STAs 104 transmit an NFR 712, the first STA 104 may transmit a trigger-based PPDU 716-a, the second STA 104 may transmit a trigger-based PPDU 716-b, and the third STA 104 may transmit a trigger-based PPDU 716-c. AP 102 may then transmit a second downlink PPDU 718. Upon receiving the second downlink PPDU 718, STA(s) 104 may transmit an acknowledgment 720 for the second downlink PPDU 718.

[0104]

[0122] In the second exemplary TXOP timing diagram 704, AP102 may transmit a first downlink PPDU 722 which also includes a UORA trigger frame (labeled "DL PPDU1+UORA TF" in Figure 7). The UORA trigger frame may indicate a resource for STA104 to transmit uplink low latency data within TXOP 706. In response to the first downlink PPDU 722, STA(s) 104 receiving the first downlink PPDU 722 may transmit an acknowledgment 724 for the first downlink PPDU 722. Based on the UORA trigger frame in the first downlink PPDU 722, STA(s) 104 with low latency data to transmit may transmit a trigger-based PPDU 726 which includes each uplink low latency data triggered by the UORA trigger frame. For example, if three STA104s have uplink low latency data to transmit, the first STA104 may transmit trigger-based PPDU726-a, the second STA104 may transmit trigger-based PPDU726-b, and the third STA104 may transmit trigger-based PPDU726-c. AP102 may then transmit a second downlink PPDU 728. An STA(s)104 receiving the second downlink PPDU728 may transmit an acknowledgment 730 for the second downlink PPDU728.

[0105]

[0123] Figure 8 shows an example of a downlink TXOP timing diagram 800 with EDCA-based preemption of transmits within a TXOP to support low-latency channel access. The downlink TXOP timing diagram 800 with EDCA-based preemption of transmits within a TXOP can, or may be, implement an embodiment of the wireless communication network 100.

[0106]

[0124] The first exemplary TXOP timing diagram 802 shows an example in which STA 104 sends a preemption instruction in TXOP 806 assigned to AP 102 after an acknowledgment of a downlink PPDU 808 from AP 102. For example, Figure 8 shows that AP 102 may send a first downlink PPDU 808 (labeled "DL PPDU+PR allowed" in Figure 8) containing an instruction in TXOP 806 that preemption is permitted. An STA(s) 104 receiving the downlink PPDU 808 may send an acknowledgment 810 to the downlink PPDU 808. An STA(s) 104 with uplink low latency data to send may send a preemption instruction 812 during a time period (such as SIFS) after the acknowledgment 810. In some examples, the preemption instruction 812 may be a clear to send (CTS) frame. In some cases, the preemption instruction 812 may be a null data packet (for example, it may only have a PHY header). The preemption instruction(s) 812 may preempt the downlink PPDU 814 (labeled "DL PPDU2" in Figure 8), and therefore AP102 may drop the downlink PPDU 814 (e.g., refrain from sending it) in response to receiving the preemption instruction(s) 812. The STA104 sending the preemption instruction 812 may be in contention to send low-latency uplink data (labeled "LL STA contention" in Figure 8). The STA104 that successfully navigates the contention may send an uplink PPDU 816 containing uplink low-latency data (labeled "UL LL data" in Figure 8). AP104 may send an acknowledgment 820 for receiving the uplink PPDU 816. In some cases, the STA(s) may not send an acknowledgment 810, but only a preemption instruction 812.

[0107]

[0125] In some examples, acknowledgment 820 may include an instruction that preemption is permitted within TXOP 806. Upon receiving acknowledgment 820 indicating that preemption is permitted, STA(s) 104 having uplink low latency data to transmit may transmit a preemption instruction 822 some time period after acknowledgment 820 (e.g., SIFS). The preemption instruction(s) 822 may preempt a third downlink PPDU 824 (labeled "DL PPDU3" in Figure 8), and therefore AP 102 may drop the third downlink PPDU 824 (e.g., refrain from transmitting it) in response to receiving the preemption instruction(s) 822. STA104, which transmits a preemption instruction 812, may compete to transmit low-latency uplink data, such as when AP102 is transmitting a third downlink 824 (indicated as "LL STA competition" in Figure 8). If STA104 successfully competes, it may transmit an uplink PPDU 826 containing uplink low-latency data (indicated as "UL LL data" in Figure 8). AP104 may transmit an acknowledgment 828 for receiving the uplink PPDU 816.

[0108]

[0126] In some examples, acknowledgment 828 may include an instruction that preemption is permitted within TXOP 806. If STA 104 does not send a preemption instruction within a certain period of time (such as within PIFS), AP 102 may send a fourth downlink PPDU 830 (labeled "DL PPDU4" in Figure 8). Upon receiving the fourth downlink PPDU 830, STA(s) 104 may send acknowledgment 832 to the fourth downlink PPDU 830. In some examples, uplink PPDUs 816 and 826 may be SU PPDUs.

[0109]

[0127] The second exemplary TXOP timing diagram 804 shows an example where STA 104 sends a preemption instruction along with an acknowledgment to a downlink PPDU. For example, Figure 8 shows that AP 102 may send a first downlink PPDU 834 (labeled "DL PPDU+PR allowed" in Figure 8) containing an instruction in TXOP 806 that preemption is permitted. Upon receiving the downlink PPDU 834, STA(s) 104 may send an acknowledgment 836 to the downlink PPDU 808. STA(s) 104 with uplink low-latency data to send may send a preemption instruction 838 along with the acknowledgment 836. For example, AP 102 may simply allocate one RU to one of the low-latency clients to indicate the preemption instruction 838. In some examples, the preemption instruction 838 may be a CTS frame. A preemption instruction (singular or plural) 838 may preempt a second downlink PPDU 840 (labeled "DL PPDU2" in Figure 8), and therefore AP102 may drop the second downlink PPDU 840 (by refraining from transmitting it) in response to receiving the preemption instruction (singular or plural) 838. STA104, which transmits the preemption instruction 838, may compete to transmit low-latency uplink data (labeled "LL STA competition" in Figure 8). An STA104 that successfully competes may transmit an uplink PPDU 842 containing uplink low-latency data (labeled "UL LL data" in Figure 8). AP102 may transmit an acknowledgment 844 for receiving the uplink PPDU 842.

[0110]

[0128] In some examples, acknowledgment 844 may contain an instruction that preemption is permitted within TXOP 806. STA(s) 104 that receive acknowledgment 844 indicating that preemption is permitted and have uplink low-latency data to transmit may transmit a preemption instruction 846 after acknowledgment 844. A preemption instruction(s) 846 may preempt a third downlink PPDU 848 (labeled "DL PPDU3" in Figure 8), and therefore AP 102 may drop the third downlink PPDU 848 (e.g., refrain from transmitting it) in response to receiving a preemption instruction(s) 846. STA 104 transmitting a preemption instruction 846 may be in competition for transmitting low-latency uplink data. STA104, having successfully competed, may transmit an uplink PPDU 850 containing uplink low latency data (labeled "UL LL data" in Figure 8). AP104 may transmit an acknowledgment 852 for receiving the uplink PPDU 850.

[0111]

[0129] Downlink low-latency traffic may arrive at AP102 before acknowledgment 852 is sent, and therefore AP102 may not include the instruction in TXOP806 that preemption is permitted in acknowledgment 852. AP102 may send a fourth downlink PPDU 854 (labeled "DL PPDU4" in Figure 8). STA(s) 104 receiving the fourth downlink PPDU 854 may send acknowledgment 856 to the fourth downlink PPDU 854. In some examples, uplink PPDUs 842 and 850 may be SU PPDUs.

[0112]

[0130] As illustrated, in EDCA-based preemption of transmissions with TXOP, AP102 may initiate preemption of transmissions with TXOP to help client devices (such as STA104) access the communication medium to send uplink SU PPDUs within AP102's TXOP806. AP initiation of transmission preemption with TXOP may be used because an AP announcement that preemption is permitted may be received by various STA104s in the BSS, reducing competition with downlink access for low-latency data. SU PPDUs may be used to help client devices (such as STA104) optimize transmission parameters (such as MCS, number of spatial streams (NSS), or bandwidth) and flush low-latency traffic within the EDCA permission.

[0113]

[0131] As shown in both the first exemplary TXOP timing diagram 802 and the second exemplary TXOP timing diagram 804, AP102 may initiate EDCA-based preemption of a transmission with a TXOP by transmitting a PPDU (such as a downlink PPDU 808 or downlink PPDU 834) that carries a preemption authorization instruction and an authorization duration (such as an authorization duration for an uplink PPDU 816 or uplink PPDU 842). In some examples, the authorization duration may begin after STA104 transmits the preemption instruction 812. In some examples, the preemption authorization instruction may be included in the PHY header of the PPDU (such as a downlink PPDU 808 or downlink PPDU 834) or in a special receiver address in a (short) control frame to reduce signaling overhead. In some examples, AP102 may initiate EDCA-based preemption of transmits with TXOPs on a PPDU basis, which may help AP102 deliver event-based downlink low-latency packets that may arrive within TXOP806. In some examples, AP102 may initiate EDCA-based preemption of transmits with TXOPs on a per-TXOP basis (for example, a preemption permission instruction may indicate that preemption is permitted for the entire TXOP806).

[0114]

[0132] As shown in the first exemplary TXOP timing diagram 802, in some examples, AP102 may wait for a PIFS duration after the downlink PPDU 808 and response frame (acknowledgment 810) before scheduling another downlink PPDU 814, so that STA104 with low latency traffic can send a preemption instruction 812 within the SIFS duration following the downlink PPDU 808 and response frame (acknowledgment 810), allowing STA104 to check the acknowledgment policy and L-SIG duration or TXOP duration. In some examples, the preemption instruction 812 may be a CTS frame sent in the SIFS frame following the downlink PPDU 808 and response frame (acknowledgment 810), so that AP102 can postpone sending the downlink PPDU 814 after the PIFS.

[0115]

[0133] In some cases, STA104 may complete the transmission of the uplink PPDU816 before the authorization ends (for example, as indicated in a preemption authorization instruction). In such cases, STA104 may send a control signal back to AP102 to indicate the return of TXOP (for example, the control signal may be a PHY header or frame, a MAC header such as an A control, or a MAC frame).

[0116]

[0134] In some cases, STA104 may receive a preemption permission instruction in the downlink PPDU808. STA104 may not detect an acknowledgment 810 or block acknowledgment after the downlink PPDU808 if, for example, the Ack policy in the downlink PPDU808 requires an Ack, and STA104 is hidden from STA104 sending an acknowledgment 810 or block acknowledgment. In such cases, a rule may be defined requiring that STA104 that does not detect an acknowledgment 810 or block acknowledgment after the downlink PPDU808 does not send a preemption instruction (e.g., an SIF after an acknowledgment 810 or block acknowledgment), and therefore STA104 that does not detect an acknowledgment 810 or block acknowledgment after the downlink PPDU808 may not be permitted to preempt TXOP806. In some examples, the timeout duration may be defined after the reception of the downlink PPDU 808, and after that timeout duration, if STA 104 does not detect an acknowledgment 810 or block acknowledgment after the downlink PPDU 808, it may send a preemption instruction 812 or begin competing for access to the channel.

[0117]

[0135] As shown in the second exemplary TXOP timing diagram 804, in some examples, AP102 may allocate a broadcast RU in a downlink PPDU 834 (which may be a downlink multi-user PPDU) (for example, a specific association ID may be defined for STA104). The broadcast RU may be used by STA104 to send a preemption instruction 838 on the response frame (acknowledgment 836) to indicate the presence of low-latency traffic. In some examples, the acknowledgment may be a block acknowledgment, and STA104 sending a block acknowledgment may support triggered response scheduling (TRS).

[0118]

[0136] Preemption authorization instructions transmitted by AP102 (such as in downlink PPDU 808, acknowledgment 820, acknowledgment 828, downlink PPDU 834, and acknowledgment 844) may enable AP102 to identify whether there are any devices with pending low-latency data within the PIFS duration following the PPDU or acknowledgment carrying the preemption authorization instruction, which can reduce unnecessary overhead and complexity that may arise from separate trigger frames (such as in NFRP / NFR or BSRP / BSR trigger-based schemes). After receiving a preemption authorization instruction, the low-latency STA 104 may transmit a preemption instruction (such as preemption instruction 812, preemption instruction 822, preemption instruction 838, or preemption instruction 846) to indicate that the low-latency STA has pending low-latency traffic. Following a preemption instruction(s)(single or multiple) by STA(s)104, STA104 may compete to transmit low-latency traffic by ignoring NAVs set by the AP in the previous frame (for example, if the AP can use multiple protection settings).

[0119]

[0137] Figure 9 shows an example of a timing diagram 900 for low-latency EDCA authorization during a downlink TXOP with immediate backoff supporting low-latency channel access. The timing diagram 900 implements, or may implement, an embodiment of the wireless communication network 100. For example, the timing diagram 900 may include AP102-a, which may be an example of AP102 as described herein. The timing diagram 900 may include legacy STA104-a, a first UHR STA104-b, a second UHR STA104-c, and a third UHR STA104-d, which may be examples of STA104 as described herein. Legacy STA104-a may not be able to preempt the TXOP assigned to AP102-a.

[0120]

[0138] NAV may be configured by AP102-a in the previous TXOP. In the current AP TXOP, AP102-a may transmit PPDU902 (labeled "PPDU+PR permitted" in Figure 9) which contains an instruction that preemption is permitted. After the SIFS period, legacy STA104-a may transmit acknowledgment 904 to PPDU902. Low-latency traffic may arrive at each of the first UHR STA104-b, second UHR STA104-c, and third UHR STA104-d during the transmission of PPDU902 or during the SIF after PPDU902. Therefore, the first UHR STA104-b, the second UHR STA104-c, and the third UHR STA104-d may each transmit an acknowledgment 904 to PPDU 902 and a preemption instruction 906 announcing the presence of low-latency traffic for transmission. In response to receiving the preemption instruction 906, AP102-a may postpone or cancel the transmission of the second downlink PPDU 908 in AP TXOP (labeled "DL PPDU2" in Figure 9), which may be scheduled for transmission after the SIFS duration following the acknowledgment 904.

[0121]

[0139] The first UHR STA104-b, the second UHR STA104-c, and the third UHR STA104-d may compete for channel access (for example, by performing a random backoff), and based on the random backoff, the second UHR STA104-c may transmit an uplink PPDU 910 (labeled "UL LL data" in Figure 9) that transmits low latency data for the second UHR STA104-c. AP102-a may transmit an acknowledgment 912 to the uplink PPDU 910. The EDCA permission duration between the preemption instruction 906 and the acknowledgment 912 may be indicated by AP102-a in the PPDU 902.

[0122]

[0140] Figure 10 shows an example of timing diagram 1000 for low-latency EDCA authorization during a downlink TXOP with immediate backoff supporting low-latency channel access. Timing diagram 1000 implements, or can implement, an embodiment of the wireless communication network 100. For example, timing diagram 1000 may include AP102-b, which may be an example of AP102 as described herein. Timing diagram 1000 may include legacy STA104-e, a first UHR STA104-f, a second UHR STA104-g, and a third UHR STA104-h, which may be examples of STA104 as described herein. Legacy STA104-e may not be able to preempt the TXOP assigned to AP102-b.

[0123]

[0141] NAV may be configured by AP102-b in the previous TXOP. In the current AP TXOP, AP102-b may transmit PPDU1002 (labeled "PPDU+PR permitted" in Figure 10) which contains an instruction that preemption is permitted. After the SIFS period, legacy STA104-e may transmit acknowledgment 1004 to PPDU1002. Low-latency traffic may arrive at the first UHR STA104-f, the second UHR STA104-g, and the third UHR STA104-h during the transmission of PPDU1002 or during the SIF after PPDU1002. Therefore, the first UHR STA104-f, the second UHR STA104-g, and the third UHR STA104-h may each transmit an acknowledgment 1004 to PPDU 1002 and a preemption instruction 1006 informing of the presence of low-latency traffic for transmission. In response to receiving the preemption instruction 1006, AP102-b may transmit a CTS frame 1008 indicating that AP102-b has postponed or canceled the transmission of the second downlink PPDU 1010 (labeled "DL PPDU2" in Figure 10) in AP TXOP.

[0124]

[0142] The first UHR STA104-f, the second UHR STA104-g, and the third UHR STA104-h may compete for channel access (for example, by performing a random backoff), and based on the random backoff, the second UHR STA104-g may transmit an uplink PPDU 1012 (labeled "UL LL data" in Figure 10) that transmits low latency data for the second UHR STA104-g. AP102-b may transmit an acknowledgment 1014 to the uplink PPDU 1012. The EDCA permission duration between the CTS frame 1008 and the acknowledgment 1014 may be indicated by AP102-b in the PPDU 902.

[0125]

[0143] Figure 11 shows an example of a timing diagram 1100 for low-latency EDCA authorization in an uplink TXOP supporting low-latency channel access. The timing diagram 1100 implements, or can implement, an embodiment of the wireless communication network 100. For example, the timing diagram 1000 may include AP102-c, which may be an example of AP102 as described herein. The timing diagram 1000 may include a first UHR STA104-i, a second UHR STA104-j, and a third UHR STA104-k, which may be examples of STA104 as described herein. In the timing diagram 1100, the TXOP may be assigned to the first UHR STA104-i.

[0126]

[0144] The NAV may be set by AP102-b in the previous TXOP. The first UHR STA104-i may send an uplink PPDU 1102 (labeled "PPDU1" in Figure 11) to AP102-c. The uplink PPDU 1102 may contain an instruction that preemption is permitted. After the SIFS duration, AP102-c may send an acknowledgment 1104 to the uplink PPDU 1102. Downlink low-latency traffic may arrive at AP102-c during the uplink PPDU 1102 or during the SIF period after the uplink PPDU 1102. Therefore, AP102-c may send a preemption instruction 1106 along with the acknowledgment 1104. A preemption instruction 1106 may indicate that the first UHR STA104-b will postpone or cancel the transmission of the second uplink PPDU 1108 (labeled "PPDU2" in Figure 11). After the SIFS duration following the preemption instruction 1106, AP102-c may transmit a downlink PPDU 1110 (labeled "PPDU+PR permitted" in Figure 11) containing downlink low latency traffic.

[0127]

[0145] In some examples, the downlink PPDU 1110 may include an instruction that preemption is permitted. Uplink low-latency traffic may arrive at the second UHR STA 104-j and the third UHR STA 104-k before the transmission of the downlink PPDU 1110. During the SIFS period after the transmission of the downlink PPDU 1110, the second UHR STA 104-j and the third UHR STA 104-k may transmit a CTS frame 1112 using resources indicated by AP 102-c (such as in the downlink PPDU 1110), where the CTS frame 1112 may announce that the second UHR STA 104-j and the third UHR STA 104-k have uplink low-latency traffic to transmit. Receipt of CTS frame 1112 may cause AP102-c to cancel or postpone downlink PPDU 1116 (labeled "DL PPDU2" in Figure 11). The second UHR STA104-j and the third UHR STA104-k may compete to send low-latency uplink data, and the second UHR STA104-j may succeed in the competition. Thus, the second UHR STA104-j may transmit uplink PPDU 1114 (labeled "UL LL data" in Figure 11). The EDCA permission period may be equal to the NAV set by CTS frame 1112 and may extend from the PIFS duration after downlink PPDU 1110 to the end of uplink PPDU 1114.

[0128]

[0146] Figure 12 shows an example of timing diagram 1200 for low-latency EDCA authorization in a downlink TXOP supporting low-latency channel access. Timing diagram 1200 implements, or can implement, an embodiment of wireless communication network 100. For example, timing diagram 1200 may include AP102-d, which may be an example of AP102 as described herein. Timing diagram 1200 may include legacy STA104-l, a first UHR STA104-m, a second UHR STA104-n, and a third UHR STA104-o, which may be examples of STA104 as described herein.

[0129]

[0147] In some examples, low-latency devices (such as AP102 or STA104) may access the transmission medium during a TXOP assigned to another device using subslot granularity. For example, a slot may be defined as 9 microseconds, and a subslot as 4 microseconds. Subslot granularity countdown may reduce collisions within low-latency devices (such as within PIDS isolated from bursts by AP102) and may still prioritize access over legacy STA104. In some examples, AP102 may use a multicast solicitation mechanism to determine whether AP102 should send a low-latency EDCA authorization. The solicitation may be signaling such as a low-latency multi-user RTS or CTS or equivalent. The purpose of the solicitation may be to determine whether any device has pending low-latency data.

[0130]

[0148] Referring to Figure 12, the Arbitration inter-frame spacing (AIFS) and one or more time periods T s Subsequently, AP102-d may initiate low-latency EDCA authorization via the transmission of PPDU1202 carrying a preemption authorization instruction (labeled "PPDU+PR authorization" in Figure 12). In some examples, PPDU1202 may indicate a low-latency EDCA authorization duration. The preemption authorization instruction may be included in the PHY header or within the MAC header frame to reduce overhead (it may be piggybacked in PPDU1202 or in a short control frame such as a CTS or RTS with a special receiver address).

[0131]

[0149] Uplink low-latency traffic may arrive at the first UHR STA104-m, the second UHR STA104-n, and the third UHR STA104-o before the end of transmission of PPDU1202. The first UHR STA104-m, the second UHR STA104-n, and the third UHR STA104-o may begin competing after the end of PPDU1202 (e.g., immediately after PPDU1202 or after the SIFS duration). For example, delay D could be the delay for competition to begin between the first UHR STA104-m, the second UHR STA104-n, and the third UHR STA104-o, and the competition granularity could be a time period T which could be a subslot. s Based on this, delay D' may be the duration during which legacy STA104-l is unable to access the channel (e.g., PIFS burst, NAV / CTS timeout, or NAV duration). As shown in the diagram, the second UHR STA104-n may successfully navigate the contention and transmit an uplink PPDU1204 carrying low-latency traffic (labeled "UL LL data" in Figure 12) within the low-latency EDCA permission duration. AP102-d may transmit a second downlink PPDU1206 (labeled "DL PPDU2" in Figure 12) after the SIFS duration following the low-latency EDCA permission duration.

[0132]

[0150] Figure 13 shows an example of a timing diagram 1300 for low-latency EDCA authorization in a downlink TXOP using subslot granularity to support low-latency channel access. The timing diagram 1300 implements, or can implement, an embodiment of the wireless communication network 100. For example, the timing diagram 1300 may include AP102-e, which may be an example of AP102 as described herein. The timing diagram 1300 may include legacy STA104-p, a first UHR STA104-q, a second UHR STA104-r, and a third UHR STA104-s, which may be examples of STA104 as described herein.

[0133]

[0151] AIFS duration and one or more sub-slots T s Subsequently, AP102-d may initiate low-latency EDCA authorization via the transmission of PPDU1302 carrying a preemption authorization instruction (labeled "PPDU+PR authorization" in Figure 13). In some examples, PPDU1302 may indicate a low-latency EDCA authorization duration. The preemption authorization instruction may be included in the PHY header or within the MAC header frame to reduce overhead (it may be piggybacked in PPDU1302 or in a short control frame such as a CTS or RTS with a special receiver address).

[0134]

[0152] Uplink low-latency traffic may arrive at the first UHR STA104-q, the second UHR STA104-r, and the third UHR STA104-s before the end of transmission of PPDU1202. The first UHR STA104-q, the second UHR STA104-r, and the third UHR STA104-s may begin competing after the end of PPDU1302 (e.g., immediately after PPDU1302 or after the SIFS duration). The competition granularity is subslot T s This may be based on (e.g., 4 microseconds). As shown in the diagram, the second UHR STA104-r may successfully compete and transmit an uplink PPDU1304 carrying low latency traffic (labeled "UL LL data" in Figure 13) within the low latency EDCA permission duration. The transmission of uplink PPDU1304 may preempt a downlink PPDU1306 (labeled "DL PPDU2" in Figure 12) scheduled after the PIFS duration following PPDU1302. AP102-d may transmit a downlink PPDU1308 (labeled "DL PPDU3" in Figure 12) after the SIFS duration following the termination of uplink PPDU1304.

[0135]

[0153] Figure 14 shows an example of timing diagram 1400 for low-latency EDCA authorization in a downlink TXOP supporting low-latency channel access. Timing diagram 1400 implements, or can implement, an embodiment of the wireless communication network 100. For example, timing diagram 1400 may include AP102-f, which may be an example of AP102 as described herein. Timing diagram 1400 may include legacy STA104-t, a first UHR STA104-u, a second UHR STA104-v, and a third UHR STA104-w, which may be examples of STA104 as described herein.

[0136]

[0154] AIFS and one or more time periods T s Subsequently, AP102-g may transmit frame 1402 containing a preemption authorization instruction (labeled "RTS / CTS (Special RA) + PR authorization" in Figure 14).

[0137]

[0155] In some cases, frame 1402 may be an RTS frame with a special receiver address when a preemption allow instruction is permitted. The NAV timeout can be approximately 100 microseconds (NAV timeout = (2 x aSIFStime) + (CTS_Time) + (aRxPHYStartDelay) + (2 x aSlotTime), etc.), which may allow up to 10 random time slots (9 microsecond slots) to be used by competing STA104s.

[0138]

[0156] In some examples, frame 1402 may be a CTS frame with a special receiver address when a preemption authorization instruction is permitted. The duration or ID field of the CTS may indicate a low-latency EDCA authorization duration, and the NAV may be set as the same NAV for legacy STA104s (such as legacy STA104-t). UHR STA104s (e.g., first UHR STA104-u, second UHR STA104-v, and third UHR STA104-w) may compete for channel access using up to N random time slots. AP102-f may use a multicast solicitation mechanism before sending a CTS.

[0139]

[0157] As shown in the diagram, the second UHR STA104-v can successfully compete and transmit an uplink PPDU 1404 (labeled "UL PPDU" in Figure 14) carrying low-latency traffic within the low-latency EDCA permission duration.

[0140]

[0158] In some examples, if an STA104 uses information from an RTS frame or multi-user RTS trigger frame as the most recent basis for updating the NAV settings for the STA104, it may be permitted to reset the NAV for the STA104 if the PHY-RXEARLYSIG instruction or PHY-RXSTART instruction primitive is not received from the PHY during the NAV timeout period, which begins when the MAC receives the PHY-RXEND instruction primitive corresponding to the detection of the RTS frame or MU-RTS trigger frame. In a non-DMG BSS, the NAV timeout period may be equal to (2xaSIFStime)+(CTS_Time)+(aRxPHYStartDelay)+(2xaSlotTime). In a non-SIG STA104 (such as 11ax), if an RTS frame is used for the most recent NAV update, CTS_TIME may be calculated using the length of the CTS frame and the data rate at which the RTS frame used for the most recent NAV update was received. If a multi-user RTS trigger frame was used for the most recent NAV update, CTS_Time can be calculated using the length of the CTS frame and a data rate of 6 Mb / s (multi-user RTS or trigger / CTS frame exchange sequence procedure).

[0141]

[0159] In some cases, after sending an RTS frame, STA104 may wait for a CTSTimeout interval with the value aSIFSTime + aSlotTime + aRxPHYStartDelay. This interval begins when MAC receives PHY0TXEND.confirmprimitive. If the PHY-RXEARLYSIG.indication or PHY-RXSTART.indication primitive does not occur during the CTSTimeout interval, STA can conclude that the RTS frame transmission failed, and STA can invoke its backoff procedure upon the expiration of the CTSTimeout interval. If the PHY-RXEARLYSIG.indication or PHY-RXSTART.indication primitive does occur during the CTSTimeout interval, STA may wait for the corresponding PHY-RXEND.indication primitive to determine whether the RTS frame transmission was successful. Recognition of a valid CTS frame sent by the RTS frame receiver, corresponding to this PHY-RXEND.indication primitive, may be interpreted as a successful response, allowing the frame exchange to continue. The recognition of other valid frames, or other similar events, may be interpreted as a failure to transmit an RTS frame. The STA can then process the received frame by calling its backoff procedure in the PHY-RXEND.indication primitive.

[0142]

[0160] FIG. 15 shows an example of a timing diagram 1500 including an AP multicast request mechanism before low-latency EDCA grant that supports low-latency channel access. Timing diagram 1500 may implement or be implemented by aspects of wireless communication network 100. For example, timing diagram 1500 may include AP 102-g, which may be an example of AP 102 described herein. Timing diagram 1500 may include legacy STA 104-x, a first UHR STA 104-y, a second UHR STA 104-z, and a third UHR STA 104-aa, which may be examples of STAs 104 as described herein.

[0143]

[0161] after AIFS and one or more time periods T s thereafter, AP 102-g may transmit a low-latency multicast request 1502 (labeled "LL MS" in FIG. 15) to determine whether AP 102-g should send an EDCA grant. The low-latency multicast request 1502 may be signaling such as a low-latency multi-user RTS or CTS, and may be used to check whether any STA 104 has pending low-latency data.

[0144]

[0162] Uplink low-latency traffic may arrive at the first UHR STA 104-y, the second UHR STA 104-z, and the third UHR STA 104-aa, and accordingly, each of the first UHR STA 104-y, the second UHR STA 104-z, and the third UHR STA 104-aa may transmit a response frame 1504 (such as an NDP or CTS frame) indicating that the first UHR STA 104-y, the second UHR STA 104-z, and the third UHR STA 104-aa respectively have uplink low-latency traffic for transmission.

[0145]

[0163] In response to response frame 1504, AP102-g may transmit a downlink PPDU 1506 indicating that preemption is permitted (labeled "DL PPDU" in Figure 15). The downlink PPDU 1506 may indicate a low-latency EDCA permit duration. If AP102-g does not receive a response to the low-latency multicast request 1502, AP102-g may not include a preemption permit instruction in the downlink PPDU 1506. During the SIFS duration following the downlink PPDU 1506, the first UHR STA104-y, the second UHR STA104-z, and the third UHR STA104-aa may compete for channel access. As shown in the diagram, the second UHR STA104-z may successfully compete and transmit an uplink PPDU 1508 carrying low-latency traffic within the low-latency EDCA permission duration (labeled "UL PPDU" in Figure 15). As shown in the diagram, duration D' refers to the duration during which a legacy STA104 (such as a legacy STA104-x) may not access the channel (such as a PIFS burst, NAV / CTS timeout, or NAV duration).

[0146]

[0164] Figure 16 shows an example of a process flow 1600 that supports low-latency channel access. The process flow 1600 includes a first wireless communication device 1602-a and a second wireless communication device 1602-b, which may be examples of AP102 or STA104 as described herein. In the following description of the process flow 1600, the operations between the first wireless communication device 1602-a and the second wireless communication device 1602-b may be transmitted in an order different from the illustrative order shown, or the operations performed by the first wireless communication device 1602-a and the second wireless communication device 1602-b may be performed in a different order or at different times. Some operations may also be omitted from the process flow 1600, and other operations may be added to the process flow 1600.

[0147]

[0165] In 1604, the first wireless communication device 1602-a may transmit a preemption instruction associated with low latency data in the first wireless communication device during the interframe space between the end time of the first PPDU from the second wireless communication device 1602-b and the scheduled start time for the second PPDU from the second wireless communication device 1602-b, where the first and second PPDUs are scheduled within a TXOP associated with the second wireless communication device 1602-b.

[0148]

[0166] In 1606, the first wireless communication device 1602-a may transmit a third PPDU based on a preemption instruction, wherein the third PPDU preempts the second PPDU within the TXOP.

[0149]

[0167] In some examples, the first wireless communication device 1602-a may receive a preemption permit or preemption enable instruction for a TXOP in the first PPDU, where the transmission of a preemption instruction is based on a preemption permit instruction. In some examples, a preemption permit instruction indicates that preemption is permitted for the entire TXOP. In some examples, the preemption permit instruction is contained in either the physical layer header of the first PPDU or the receiver address field of the first PPDU.

[0150]

[0168] In some examples, the first wireless communication device 1602-a may transmit a response frame to the first PPDU to the second wireless communication device 1602-b in interframe space, where the transmission of a preemption instruction follows the transmission of the response frame. In some examples, the preemption instruction is transmitted via a CTS frame. In some examples, the response frame may be a block acknowledgment.

[0151]

[0169] In some examples, the first wireless communication device 1602-a may transmit a response to the first PPDU in 1604 within the same frame as the preemption instruction. In some examples, the first wireless communication device 1602-a receives an instruction for a broadcast RU to transmit a preemption instruction in the first PPDU, and the preemption instruction is transmitted via the broadcast RU.

[0152]

[0170] In some examples, a first wireless communication device 1602-a may receive a frame from a second wireless communication device 1602-b in response to a preemption instruction, and a third PPDU transmission may respond to the frame.

[0153]

[0171] In some examples, the first wireless communication device 1602-a may, based on the transmission of a preemption instruction, execute a Listen Before Talk (LBT) procedure within a time period following the preemption instruction, where the transmission of a third PPDU is based on the LBT procedure, where the duration of the time period is indicated to the first wireless communication device by the second wireless communication device 1602-b, where the transmission of the third PPDU is within the permitted duration indicated to the first wireless communication device 1602-a by the second wireless communication device 1602-b. In some examples, the LBT procedure uses subslot granularity to determine the start time for the third PPDU, where the subslots have a duration of less than 9 microseconds (for example, for a 5 or 6 GHz channel using 9 microsecond slots). In some examples, the subslots may have a duration of less than 20 microseconds (for example, for a 2.4 GHz channel using 20 microsecond slots).

[0154]

[0172] In some examples, the third PPDU is transmitted within a time period corresponding to the second interframe space after the transmission of the preemption instruction. In some examples, the first wireless communication device 1602-a may receive an instruction from the second wireless communication device 1602-b regarding the duration of the second interframe space. In some examples, the time period corresponding to the second interframe space may be the number of slots (for example, the second wireless communication device 1602-b may indicate the number of slots as the duration of the second interframe space).

[0155]

[0173] In some examples, a first wireless communication device 1602-a and a second wireless communication device 1602-b may receive a second preemption instruction from the third wireless communication device in the second interframe space of the TXOP between the end time of the third PPDU and the scheduled start time for receiving the fourth PPDU from the second wireless communication device 1602-b, where the fourth PPDU is scheduled for reception within the TXOP. Based on the second preemption instruction, the first wireless communication device 1602-a may refrain from monitoring the fourth PPDU. The second wireless communication device 1602-b may receive a fifth PPDU from the third wireless communication device and, based on the second preemption instruction, where the fifth PPDU preempts the fourth PPDU within the TXOP. In some examples, a first wireless communication device 1602-a may receive a response frame from a second wireless communication device 1602-b for a third PPDU containing a preemption authorization instruction for TXOP, and the receipt of the second preemption instruction is a response to the preemption authorization instruction.

[0156]

[0174] In some examples, the first wireless communication device 1602-a may refrain from monitoring the second PPDU based on a preemption instruction. In some examples, the second wireless communication device 1602-b may refrain from transmitting the second PPDU based on a preemption instruction.

[0157]

[0175] In some examples, the first wireless communication device 1602-a and the second wireless communication device 1602-b may have scheduling information to schedule the first PPDU and the second PPDU within the TXOP.

[0158]

[0176] In some examples, the first wireless communication device 1602-a is an AP (Access Point), and the second wireless communication device 1602-b is an STA (Stand-Aid).

[0159]

[0177] In some examples, the inter-frame space is one of the following: short inter-frame space, point-coordinated inter-frame space, or a competition window with random backoff.

[0160]

[0178] [The inventors should describe any other way in which the invention can be constructed, performed, or used in a manner different from that disclosed.]

[0179] Figure 17 shows a block diagram of an exemplary wireless communication device 1700 that supports low-latency channel access. In some examples, the wireless communication device 1700 is configured to perform processes 1800 and 1900, respectively, with reference to Figures 18 and 19. The wireless communication device 1700 may include one or more chips, SoCs, chipsets, packages, components, or devices that constitute a processing system individually or collectively, or that include a processing system. The processing system can interface with other components of the wireless communication device 1700 and, generally, can process information (such as inputs or signals) received from such other components and output information (such as outputs or signals) to such other components. In some embodiments, the exemplary chip may include a processing system, a first interface for outputting or transmitting information, and a second interface for receiving or acquiring information. For example, the first interface may refer to an interface between the processing system and a transmitting component of the chip, thereby enabling the wireless communication device 1700 to transmit information output from the chip. In such examples, the second interface may refer to an interface between the chip's processing system and the receiving component, and the wireless communication device 1700 may then receive information to be passed to the processing system. In some such examples, the first interface may also acquire information from, for example, the transmitting component, and the second interface may also output information to, for example, the receiving component.

[0161]

[0180] The processing system of the wireless communication device 1700 includes one or more processors, microprocessors, processing units (such as central processing units (CPUs), graphics processing units (GPUs), or digital signal processors (DSPs)), processing blocks, application-specific integrated circuits (ASICs), programmable logic devices (PLDs) (such as field-programmable gate arrays (FPGAs)), or other discrete gate or transistor logic or circuit configurations (all of which may be referred to herein collectively as "processors" individually or collectively as "processors" or "processor circuit configurations"). One or more of these processors may or may be configured to perform various functions or operations individually or collectively as described herein. The processing system may further include one or more memory devices, memory blocks, memory elements, or memory circuit configurations in the form of other discrete gates or transistor logic or circuit configurations (all of which may be referred to herein collectively as “memory” individually or collectively as “memory” or “memory circuit configuration”), each of which may include tangible storage media such as random access memory (RAM) or ROM, or combinations thereof. One or more of the memories may be coupled with one or more of the processors and may individually or collectively store processor executable code that, when executed by one or more of the processors, can configure one or more of the processors to perform the various functions or operations described herein. In addition or alternatively, in some examples, one or more of the processors may be pre-configured to perform the various functions or operations described herein without requiring software configuration. The processing system may further include, or be coupled with, one or more modems (such as a Wi-Fi (IEEE compliant, etc.) modem or a cellular (3GPP 4G LTE, 5G, or 6G compliant, etc.) modem).In some implementations, one or more processors in the processing system include or implement one or more modems. The processing system may further include or be coupled with multiple radios (collectively, “radios”), multiple RF chains, or multiple transceivers, each of which may then be coupled with one or more of multiple antennas. In some implementations, one or more processors in the processing system include or implement one or more radios, RF chains, or transceivers.

[0162]

[0181] In some examples, the wireless communication device 1700 may be configured for use in an AP or STA, such as AP102 or STA104 as described with reference to Figure 1. In some other examples, the wireless communication device 1700 may be an AP or STA including such a processing system and other components including multiple antennas. The wireless communication device 1700 is capable of transmitting and receiving wireless communications, for example, in the form of wireless packets. For example, the wireless communication device 1700 may be configured to transmit and receive packets in the form of physical layer PPDU and MPDU conforming to one or more of the IEEE 802.11 family of wireless communication protocol standards. In some other examples, the wireless communication device 1700 may be configured to transmit and receive signals and communications conforming to one or more 3GPP specifications, including those relating to 5G NR or 6G. In some examples, the wireless communication device 1700 may also include, or be coupled with, one or more application processors, which may be further coupled to one or more additional memories. In some examples, the wireless communication device 1700 further includes a user interface (UI) (such as a touchscreen or keypad) and a display that can be integrated with the UI to form a touchscreen display coupled with the processing system. In some examples, the wireless communication device 1700 may further include one or more sensors coupled with the processing system, such as one or more inertial sensors, accelerometers, temperature sensors, pressure sensors, or altitude sensors. In some examples, the wireless communication device 1700 further includes at least one external network interface coupled with the processing system that enables communication with a core network or backhaul network, which allows the wireless communication device 1700 to access an external network, including the Internet.

[0163]

[0182] The wireless communication device 1700 includes a preemption instruction manager 1725, a PPDU preemption manager 1730, a preemption permission instruction manager 1735, a response frame manager 1740, a preemption instruction response manager 1745, an LBT manager 1750, a PPDU monitoring manager 1755, a PPDU scheduling manager 1760, a broadcast RU manager 1765, and a PPDU timing manager 1770. One or more of the preemption instruction manager 1725, PPDU preemption manager 1730, preemption permission instruction manager 1735, response frame manager 1740, preemption instruction response manager 1745, LBT manager 1750, PPDU monitoring manager 1755, PPDU scheduling manager 1760, broadcast RU manager 1765, and PPDU timing manager 1770 may be implemented at least partially in hardware or firmware. For example, one or more of the preemption instruction manager 1725, PPDU preemption manager 1730, preemption permission instruction manager 1735, response frame manager 1740, preemption instruction response manager 1745, LBT manager 1750, PPDU monitoring manager 1755, PPDU scheduling manager 1760, broadcast RU manager 1765, and PPDU timing manager 1770 may be implemented at least partially by a processor or modem. In some examples, one or more of the preemption instruction manager 1725, PPDU preemption manager 1730, preemption permission instruction manager 1735, response frame manager 1740, preemption instruction response manager 1745, LBT manager 1750, PPDU monitoring manager 1755, PPDU scheduling manager 1760, broadcast RU manager 1765, and PPDU timing manager 1770 may be implemented at least partially by the processor and software in the form of processor-executable code stored in memory.

[0164]

[0183] The wireless communication device 1700 may include a communication manager 1720 that can support wireless communication as illustrated herein. The preemption instruction manager 1725 is configured to transmit a preemption instruction related to low latency data in the first wireless communication device during the interframe space between the end time of a first PPDU from the second wireless communication device and the scheduled start time for a second PPDU from the second wireless communication device, wherein the first and second PPDUs are scheduled within a TXOP related to the second wireless communication device. The PPDU preemption manager 1730 is configured to transmit a third PPDU based on the preemption instruction, wherein the third PPDU preempts the second PPDU within a TXOP.

[0165]

[0184] In some examples, the preemption authorization instruction manager 1735 can be configured to receive a preemption authorization instruction for a TXOP in a first PPDU, where the transmission of a preemption instruction is based on a preemption authorization instruction.

[0166]

[0185] In some cases, a preemption permission directive indicates that preemption is permitted for the entire TXOP.

[0167]

[0186] In some cases, the preemption authorization instruction is included in either the physical layer header of the first PPDU or the receiver address field of the first PPDU.

[0168]

[0187] In some examples, the response frame manager 1740 can be configured to send a response frame for the first PPDU to a second wireless communication device in interframe space, where the transmission of a preemption instruction follows the transmission of the response frame.

[0169]

[0188] In some cases, preemption instructions may be sent via CTS frames.

[0170]

[0189] In some examples, the preemption instruction manager 1725 can be configured to send a response to the first PPDU in the same frame as the preemption instruction.

[0171]

[0190] In some examples, the broadcast RU manager 1765 can be configured to receive, or is configured to receive, a broadcast RU instruction for sending a preemption instruction in a first PPDU, where the preemption instruction is sent via the broadcast RU.

[0172]

[0191] In some examples, the preemption instruction response manager 1745 can be configured to receive a frame from a second wireless communication device in response to a preemption instruction, where the transmission of a third PPDU is in response to the frame.

[0173]

[0192] In some examples, the LBT manager 1750 can be configured to execute an LBT procedure within a time period following a preemption instruction, based on the transmission of a preemption instruction, where the transmission of a third PPDU is based on the LBT procedure, the duration of the time period is indicated to the first wireless communication device by the second wireless communication device, and the transmission of the third PPDU is within the permitted duration indicated to the first wireless communication device by the second wireless communication device.

[0174]

[0193] In some examples, the LBT procedure used subslot granularity to determine the start time for the third PPDU. In some examples, the subslots had a duration of less than 9 microseconds.

[0175]

[0194] In some examples, the third PPDU is sent within a time period corresponding to the second interframe space after the transmission of the preemption instruction.

[0176]

[0195] In some examples, the PPDU timing manager 1770 can be configured to receive instructions for the duration of a second interframe space from a second wireless communication device.

[0177]

[0196] In some examples, the preemption instruction manager 1725 can be configured to receive a second preemption instruction from the third wireless communication device associated with low-latency data in the third wireless communication device in the second interframe space of the TXOP between the end time of the third PPDU and the scheduled start time for receiving the fourth PPDU from the second wireless communication device, where the fourth PPDU is scheduled for reception within the TXOP. In some examples, the PPDU monitoring manager 1755 can be configured to refrain from monitoring the fourth PPDU based on the second preemption instruction.

[0178]

[0197] In some examples, the preemption authorization instruction manager 1735 can be configured to receive a response frame from a second wireless communication device for a third PPDU containing a preemption authorization instruction for TXOP, where the receipt of the second preemption instruction is a response to the preemption authorization instruction.

[0179]

[0198] In some examples, the PPDU monitoring manager 1755 can be configured, or is configured, to refrain from monitoring a second PPDU based on a preemption instruction.

[0180]

[0199] In some examples, the PPDU scheduling manager 1760 can be configured to receive scheduling information to schedule a first PPDU and a second PPDU within a TXOP.

[0181]

[0200] In some examples, the first wireless communication device is an AP (Access Point), and the second wireless communication device is an STA (Stationary Device).

[0182]

[0201] In some examples, the inter-frame space is one of the following: short inter-frame space, point-coordinated inter-frame space, or a competition window with random backoff.

[0183]

[0202] Additionally or alternatively, the wireless communication device 1700 can support wireless communication in accordance with embodiments such as those disclosed herein. In some examples, the preemption instruction manager 1725 is configured to receive a preemption instruction from the first wireless communication device associated with low-latency data in the first wireless communication device in the interframe space between the end time of the first PPDU from the second wireless communication device and the scheduled start time for the second PPDU from the second wireless communication device, wherein the first and second PPDUs are scheduled within a TXOP associated with the second wireless communication device. In some examples, the preemption instruction manager 1725 is configured to receive a third PPDU from the first wireless communication device and, based on the preemption instruction, wherein the third PPDU preempts the second PPDU within a TXOP.

[0184]

[0203] In some examples, the preemption authorization instruction manager 1735 can be configured to send a preemption authorization instruction for TXOP in the first PPDU, where the sending of the preemption instruction is based on the preemption authorization instruction.

[0185]

[0204] In some cases, a preemption permission directive indicates that preemption is permitted for the entire TXOP.

[0186]

[0205] In some cases, the preemption authorization instruction is included in either the physical layer header of the first PPDU or the receiver address field of the first PPDU.

[0187]

[0206] In some examples, the response frame manager 1740 can be configured to receive a response frame for a first PPDU from a first wireless communication device in interframe space, where the reception of a preemption instruction follows the reception of the response frame.

[0188]

[0207] In some cases, preemption instructions are received via CTS frames.

[0189]

[0208] In some examples, the preemption instruction manager 1725 can be configured to receive a response frame for the first PPDU from the first wireless communication device in the same frame as the preemption instruction.

[0190]

[0209] In some examples, the broadcast RU manager 1765 can be configured to send a broadcast RU instruction for sending a preemption instruction in the first PPDU, where the preemption instruction is received via the broadcast RU.

[0191]

[0210] In some examples, the preemption instruction response manager 1745 can be configured or is configured to send a frame in response to a preemption instruction, where the receipt of a third PPDU is in response to the frame.

[0192]

[0211] In some examples, the third PPDU is received during a time period corresponding to the second interframe space after the receipt of the preemption instruction.

[0193]

[0212] In some examples, the PPDU timing manager 1770 can be configured to send instructions to a first wireless communication device regarding the duration of a second interframe space.

[0194]

[0213] In some examples, the preemption instruction manager 1725 is configured to receive a second preemption instruction from the third wireless communication device in the second interframe space of the TXOP between the end time of the third PPDU and the scheduled start time for receiving the fourth PPDU from the second wireless communication device, where the fourth PPDU is scheduled for reception within the TXOP. In some examples, the PPDU preemption manager 1730 is configured to receive a fifth PPDU from the third wireless communication device and, based on the second preemption instruction, where the fifth PPDU preempts the fourth PPDU within the TXOP.

[0195]

[0214] In some examples, the preemption authorization instruction manager 1735 can be configured to send a response frame for a third PPDU containing a preemption authorization instruction for TXOP, where the receipt of the second preemption instruction is a response to the preemption authorization instruction.

[0196]

[0215] In some examples, the PPDU preemption manager 1730 can be configured, or is configured, to refrain from sending a second PPDU based on a preemption instruction.

[0197]

[0216] In some examples, the PPDU scheduling manager 1760 can be configured to send scheduling information within the TXOP to schedule the first and second PPDUs.

[0198]

[0217] In some examples, the first wireless communication device is an AP (Access Point), and the second wireless communication device is an STA (Stationary Device).

[0199]

[0218] In some examples, the inter-frame space is one of the following: short inter-frame space, point-coordinated inter-frame space, or a competition window with random backoff.

[0200]

[0219] Figure 18 shows a flowchart illustrating an exemplary process 1800 that can be performed by or in a first wireless communication device supporting low-latency channel access. The operation of process 1800 can be performed by the first wireless communication device or its components, as described herein. For example, process 1800 may be performed by a wireless communication device, such as wireless communication device 1700, described with reference to Figure 17, which operates as a wireless AP or wireless STA, or operates within a wireless STA or wireless AP. In some embodiments, process 1800 may be performed by a wireless AP or wireless STA, such as one of AP102 or STA104, described with reference to Figure 1.

[0201]

[0220] In some examples, in block 1805, the first wireless communication device may transmit a preemption instruction related to low-latency data in the first wireless communication device during the interframe space between the end time of the first PPDU from the second wireless communication device and the scheduled start time for the second PPDU from the second wireless communication device, where the first and second PPDUs are scheduled within a TXOP related to the second wireless communication device. The operation of block 1805 may be carried out according to examples disclosed herein, such as transmitting preemption instruction 812 or preemption instruction 838 in Figure 8, preemption instruction 906 in Figure 9, preemption instruction 1006 in Figure 10, or preemption instruction 1106 in Figure 11. In some implementations, the mode of operation of block 1805 may be carried out by a preemption instruction manager 1725, as described with reference to Figure 17.

[0202]

[0221] In some examples, in block 1810, the first wireless communication device may transmit a third PPDU based on a preemption instruction, where the third PPDU preempts the second PPDU within the TXOP. The operation of block 1810 may be performed according to examples disclosed herein, such as the transmission of uplink PPDU 816 or uplink PPDU 842 in Figure 8, uplink PPDU 910 in Figure 9, uplink PPDU 1012 in Figure 10, or downlink PPDU 1110 in Figure 11. In some implementations, the operation of block 1810 may be performed by a PPDU preemption manager 1730, as described with reference to Figure 17.

[0203]

[0222] Figure 19 shows a flowchart illustrating an exemplary process 1900 that can be performed by or in a second wireless communication device supporting low-latency channel access. The operation of process 1900 can be performed by a second wireless communication device or its components, as described herein. For example, process 1900 may be performed by a wireless communication device, such as wireless communication device 1700, described with reference to Figure 17, which operates as a wireless AP or wireless STA, or operates within a wireless STA or wireless AP. In some examples, process 1900 may be performed by a wireless AP or wireless STA, such as one of AP102 or STA104, described with reference to Figure 1.

[0204]

[0223] In some examples, in block 1905, the second wireless communication device may receive a preemption instruction from the first wireless communication device associated with low-latency data in the first wireless communication device during the interframe space between the end time of the first PPDU from the second wireless communication device and the scheduled start time for the second PPDU from the second wireless communication device, where the first and second PPDUs are scheduled within a TXOP associated with the second wireless communication device. The operation of block 1905 may be carried out according to examples disclosed herein, such as receiving preemption instruction 812 or preemption instruction 838 in Figure 8, preemption instruction 906 in Figure 9, preemption instruction 1006 in Figure 10, or preemption instruction 1106 in Figure 11. In some implementations, the operation of block 1905 may be carried out by a preemption instruction manager 1725, as described with reference to Figure 17.

[0205]

[0224] In some examples, in block 1910, a second wireless communication device may receive a third PPDU from the first wireless communication device and based on a preemption instruction, where the third PPDU preempts the second PPDU within the TXOP. The operation of block 1910 may be performed according to examples disclosed herein, such as receiving uplink PPDU 816 or uplink PPDU 842 in Figure 8, uplink PPDU 910 in Figure 9, uplink PPDU 1012 in Figure 10, or downlink PPDU 1110 in Figure 11. In some implementations, the operation of block 1910 may be performed by a preemption instruction manager 1725, as described with reference to Figure 17.

[0206]

[0225] Implementation examples are described in the following numbered clauses.

[0207]

[0226] Embodiment 1: A method for wireless communication in a first wireless communication device, comprising: transmitting a preemption instruction associated with low-latency data in the first wireless communication device in the interframe space between the end time of a first PPDU from a second wireless communication device and the scheduled start time for a second PPDU from the second wireless communication device; wherein the first PPDU and the second PPDU are scheduled in a TXOP associated with the second wireless communication device, and transmitting a third PPDU that preempts the second PPDU in the TXOP, at least in part based on the preemption instruction.

[0208]

[0227] Embodiment 2: The method according to Embodiment 1, further comprising receiving a preemption authorization instruction for TXOP in the first PPDU, wherein the transmission of the preemption instruction is at least partially based on the preemption authorization instruction.

[0209]

[0228] Embodiment 3: The method according to Embodiment 2, wherein the preemption authorization instruction indicates that preemption is authorized for the entire TXOP.

[0210]

[0229] Embodiment 4: The method according to Embodiment 2 or 3, wherein the preemption permission instruction is included in either the physical layer header of the first PPDU or the receiver address field of the first PPDU.

[0211]

[0230] Embodiment 5: The method according to any one embodiment of Embodiments 1 to 4, further comprising transmitting a response frame for a first PPDU to a second wireless communication device in interframe space, wherein the transmission of a preemption instruction takes place after the transmission of the response frame.

[0212]

[0231] Embodiment 6: The method according to Embodiment 5, wherein the preemption instruction is transmitted via a CTS frame.

[0213]

[0232] Embodiment 7: The method according to any one embodiment of Embodiments 1 to 4, further comprising transmitting a response to the first PPDU in the same frame as the preemption instruction.

[0214]

[0233] Embodiment 8: The method according to Embodiment 7, further comprising receiving an instruction from a broadcast RU for transmitting a preemption instruction in the first PPDU, wherein the preemption instruction is transmitted via the broadcast RU.

[0215]

[0234] Embodiment 9: The method according to any one embodiment of Embodiments 1 to 8, further comprising receiving a frame from a second wireless communication device in response to a preemption instruction, wherein the transmission of a third PPDU responds to the frame.

[0216]

[0235] Embodiment 10: The method according to any one embodiment of Embodiments 1 to 9, further comprising performing an LBT procedure within a time period following a preemption instruction based on the transmission of a preemption instruction, wherein the transmission of a third PPDU is at least partially based on the LBT procedure, the duration of the time period is indicated to the first wireless communication device by the second wireless communication device, and the transmission of the third PPDU is within the permitted duration indicated to the first wireless communication device by the second wireless communication device.

[0217]

[0236] Embodiment 11: The method according to Embodiment 10, wherein the LBT procedure uses subslot granularity to determine the start time of the third PPDU, and the subslots have a duration of less than 9 microseconds.

[0218]

[0237] Embodiment 12: The method according to any one embodiment of Embodiments 1 to 11, wherein the third PPDU is transmitted within a time period corresponding to a second interframe space after the transmission of the preemption instruction.

[0219]

[0238] Embodiment 13: The method according to Embodiment 12, further comprising receiving instructions for the duration of a second interframe space from a second wireless communication device.

[0220]

[0239] Embodiment 14: The method of any one embodiment of Embodiments 1 to 13, further comprising receiving a second preemption instruction from the third wireless communication device in the second interframe space of the TXOP between the end time of the third PPDU and the scheduled start time for receiving the fourth PPDU from the second wireless communication device, wherein the fourth PPDU is scheduled for reception within the TXOP and refraining from monitoring the fourth PPDU based at least in part on the second preemption instruction.

[0221]

[0240] Embodiment 15: The method of Embodiment 14, further comprising receiving a response frame for a third PPDU containing a preemption authorization instruction for TXOP from a second wireless communication device, wherein the reception of the second preemption instruction is in response to the preemption authorization instruction.

[0222]

[0241] Embodiment 16: The method according to any one embodiment of Embodiments 1 to 15, further comprising refraining from monitoring a second PPDU based at least in part on a preemption instruction.

[0223]

[0242] Embodiment 17: The method according to any one embodiment of Embodiments 1 to 16, further comprising receiving scheduling information for scheduling a first PPDU and a second PPDU within TXOP.

[0224]

[0243] Clause 18: The method according to any one embodiment of embodiments 1 to 17, wherein the first wireless communication device is an access point and the second wireless communication device is a station, or the first wireless communication device is a station and the second wireless communication device is an access point.

[0225]

[0244] Embodiment 19: The method according to any one embodiment of Embodiments 1 to 18, wherein the interframe space is one of a short interframe space, a point-coordinated interframe space, or a competition window with random backoff.

[0226]

[0245] Embodiment 20: A method for wireless communication in a second wireless communication device, comprising: receiving a preemption instruction from the first wireless communication device associated with low-latency data in the first wireless communication device in the interframe space between the end time of a first PPDU from the second wireless communication device and the scheduled start time for a second PPDU from the second wireless communication device; wherein the first PPDU and the second PPDU are scheduled in a TXOP associated with the second wireless communication device, and receiving a third PPDU from the first wireless communication device and, at least in part, based on the preemption instruction, preempting the second PPDU in the TXOP.

[0227]

[0246] Embodiment 21: The method of Embodiment 20, further comprising transmitting a preemption authorization instruction for TXOP in the first PPDU, wherein the receipt of the preemption instruction is at least partially based on the preemption authorization instruction.

[0228]

[0247] Embodiment 22: The method according to Embodiment 21, wherein the preemption authorization instruction indicates that preemption is authorized for the entire TXOP.

[0229]

[0248] Embodiment 23: The method according to Embodiment 21 or 22, wherein the preemption permission instruction is included in either the physical layer header of the first PPDU or the receiver address field of the first PPDU.

[0230]

[0249] Embodiment 24: The method according to any one embodiment of Embodiments 20 to 23, further comprising receiving a response frame for a first PPDU from a first wireless communication device in interframe space, wherein the reception of a preemption instruction occurs after the reception of the response frame.

[0231]

[0250] Embodiment 25: The method according to Embodiment 24, wherein the preemption instruction is received via a CTS frame.

[0232]

[0251] Embodiment 26: The method according to any one embodiment of Embodiments 20 to 23, further comprising receiving a response frame for a first PPDU from a first wireless communication device in the same frame as the preemption instruction.

[0233]

[0252] Embodiment 27: The method of Embodiment 26, further comprising transmitting an instruction for a broadcast RU to transmit a preemption instruction in the first PPDU, wherein the preemption instruction is received via the broadcast RU.

[0234]

[0253] Embodiment 28: The method according to any one embodiment of Embodiments 20 to 27, further comprising transmitting a frame in response to a preemption instruction, wherein the reception of a third PPDU is in response to the frame.

[0235]

[0254] Embodiment 29: The method according to any one embodiment of Embodiments 20 to 28, wherein the third PPDU is received during a time period corresponding to a second interframe space after the receipt of the preemption instruction.

[0236]

[0255] Embodiment 30: The method according to Embodiment 29, further comprising transmitting an instruction for the duration of a second interframe space to a first wireless communication device.

[0237]

[0256] Embodiment 31: The method according to any one embodiment of Embodiments 20 to 30, further comprising receiving a second preemption instruction from the third wireless communication device in a second interframe space of a TXOP between the end time of a third PPDU and a scheduled start time for receiving a fourth PPDU from the second wireless communication device, the fourth PPDU being scheduled for reception in the TXOP, and receiving a fifth PPDU from the third wireless communication device, and at least in part based on the second preemption instruction, which preempts the fourth PPDU in the TXOP.

[0238]

[0257] Embodiment 32: The method according to Embodiment 31, further comprising transmitting a response frame for a third PPDU, which includes a preemption permission instruction for TXOP, wherein the receipt of the second preemption instruction is in response to the preemption permission instruction.

[0239]

[0258] Embodiment 33: The method according to any one embodiment of Embodiments 20 to 32, further comprising refraining from transmitting a second PPDU based at least in part on a preemption instruction.

[0240]

[0259] Embodiment 34: The method according to any one embodiment of Embodiments 20 to 33, further comprising transmitting scheduling information for scheduling a first PPDU and a second PPDU within a TXOP.

[0241]

[0260] Clause 35: The method according to any one embodiment of embodiments 20 to 34, wherein the first wireless communication device is an access point and the second wireless communication device is a station, or the first wireless communication device is a station and the second wireless communication device is an access point.

[0242]

[0261] Embodiment 36: The method according to any one embodiment of Embodiments 20 to 35, wherein the interframe space is one of a short interframe space, a point-coordinated interframe space, or a competition window with random backoff.

[0243]

[0262] Embodiment 37: A first wireless communication device for wireless communication, comprising one or more memories storing processor executable code, and one or more processors coupled to one or more memories, wherein one or more processors are individually or collectively operable to execute code causing the first wireless communication device to perform the method described in any one embodiment of Embodiments 1 to 19.

[0244]

[0263] Embodiment 38: A first wireless communication device for wireless communication, comprising at least one means for carrying out the method described in any one embodiment of Embodiments 1 to 19.

[0245]

[0264] Embodiment 39: A non-temporary computer-readable medium storing code for wireless communication, wherein the code includes instructions executable by a processor to carry out the method described in any one embodiment of Embodiments 1 to 19.

[0246]

[0265] Embodiment 40: A second wireless communication device for wireless communication, comprising one or more memories for storing processor executable code, and one or more processors coupled to one or more memories, individually or collectively operable to execute code to cause the second wireless communication device to perform the method described in any one embodiment of Embodiments 20 to 36.

[0247]

[0266] Embodiment 41: A second wireless communication device for wireless communication, comprising at least one means for carrying out the method described in any one embodiment of Embodiments 20 to 36.

[0248]

[0267] Embodiment 42: A non-temporary computer-readable medium storing code for wireless communication, wherein the code includes instructions executable by a processor to carry out the method described in any one embodiment of Embodiments 20 to 36.

[0249]

[0268] As used herein, the terms “determine” or “determining” encompass a wide range of actions, and therefore “determining” may include, among other possibilities, calculating, calculating, processing, deriving, estimating, investigating, searching (such as by searching within a table, database, or other data structure), inferring, confirming, or measuring. “Determining” may also include, among other possibilities, receiving (such as receiving information), accessing (such as accessing data stored in memory), or transmitting (such as transmitting information). Furthermore, “deciding” may also include resolving, selecting, obtaining, choosing, establishing, and other similar actions.

[0250]

[0269] As used herein, the phrases "at least one of" or "one or more of" the list of items refer to any combination of those items, including a single member. For example, "at least one of a, b, or c" is intended to include a, b, c, ab, ac, bc, and abc. As used herein, "or" is intended to be interpreted in an inclusive sense unless otherwise explicitly indicated. For example, "a or b" may include a only, b only, or a combination of a and b. Furthermore, as used herein, the phrases "one (a)" or "one (an)" element refer to one or more such elements that act individually or collectively to perform the listed function(singular or plural). Furthermore, "set" refers to one or more items, and "subset" refers to fewer items than the entire set but not empty.

[0251]

[0270] As used herein, “based on” is intended to be interpreted in a comprehensive sense unless otherwise explicitly indicated. For example, “based on” may be used interchangeably with “at least partially based on,” “associated with,” “following,” or “according to,” unless otherwise explicitly indicated. Specifically, unless the phrase “based on ‘a’ alone” or refers to an equivalent in the context, whatever “based on ‘a’” or “at least partially based on ‘a’” may be based on “a” alone or on “a” in combination with one or more other factors, conditions, or pieces of information.

[0252]

[0271] The various exemplary components, logic, logic blocks, modules, circuits, operations, and algorithmic processes described in relation to the embodiments disclosed herein may be implemented as electronic hardware, firmware, software, or combinations of hardware, firmware, or software, including the structures disclosed herein and their structural equivalents. The compatibility of hardware, firmware, and software is described conceptually in terms of functionality and is shown in the various exemplary components, blocks, modules, circuits, and processes described above. Whether such functionality is implemented in hardware, firmware, or software depends on the specific application and the design constraints imposed on the overall system.

[0253]

[0272] Various modifications to the embodiments described herein may be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other embodiments without departing from the spirit or scope of this disclosure. Therefore, the claims should not be limited to the embodiments shown herein, but should be given the broadest scope consistent with this disclosure, the principles disclosed herein, and any novel features.

[0254]

[0273] Additionally, various features described herein in the context of separate embodiments may also be implemented in combination in a single implementation. Conversely, various features described in the context of a single implementation may also be implemented separately or in any preferred partial combination in multiple embodiments. Therefore, features may be described above as acting in a particular combination, and may even be initially claimed as such, but one or more features from a claimed combination may, in some cases, be removed from that combination, and the claimed combination may cover partial combinations or variations of partial combinations.

[0255]

[0274] Similarly, while operations are shown in a specific order in the drawings, this should not be understood as requiring that such operations be performed in a specific or sequential order shown, or that all illustrated operations be performed, in order to achieve the desired result. Furthermore, drawings may schematically represent one or more exemplary processes in the form of flowcharts or flow diagrams. However, other operations not shown can be incorporated into those schematically illustrated exemplary processes. For example, one or more additional operations may be performed before, after, simultaneously with, or between any of the illustrated operations. In some situations, multitasking and parallel processing may be advantageous. Moreover, the separation of various system components in the embodiments described above should not be understood as requiring such separation in all embodiments, and it should be understood that the program components and systems described can generally be integrated together in a single software product or packaged within multiple software products.

Claims

1. A first wireless communication device, One or more memory locations for storing processor executable code, One or more processors coupled to the one or more memory, The device comprises one or more processors, and the first wireless communication device In the interframe space between the end time of the first physical layer protocol data unit from the second wireless communication device and the scheduled start time of the second physical layer protocol data unit from the second wireless communication device, the first wireless communication device is instructed to send a preemption instruction associated with low latency data, where the first physical layer protocol data unit and the second physical layer protocol data unit are scheduled within a transmission opportunity associated with the second wireless communication device, and A first wireless communication device, which is capable of individually or collectively operating to cause a third physical layer protocol data unit to transmit, at least in part, based on the preemption instruction, thereby executing the code to preempt the second physical layer protocol data unit within the transmission opportunity.

2. The one or more processors are further operable to execute the code individually or collectively, and the code is transmitted to the first wireless communication device. The first wireless communication device according to claim 1, wherein the first physical layer protocol data unit receives a preemption permission instruction for the transmission opportunity, and the transmission of the preemption instruction is at least partially based on the preemption permission instruction.

3. The first wireless communication device according to claim 2, wherein the preemption permission instruction indicates that preemption is permitted for the entire transmission opportunity.

4. The first wireless communication device according to claim 2, wherein the preemption permission instruction is included in one of the physical layer header of the first physical layer protocol data unit or the receiver address field of the first physical layer protocol data unit.

5. The one or more processors are further operable to execute the code individually or collectively, and the code is transmitted to the first wireless communication device. The first wireless communication device according to claim 1, wherein in the interframe space, the second wireless communication device transmits a response frame for the first physical layer protocol data unit, wherein the transmission of the preemption instruction occurs after the transmission of the response frame.

6. The first wireless communication device according to claim 5, wherein the preemption instruction is transmitted via a transmittable frame.

7. The one or more processors are further operable to execute the code individually or collectively, and the code is transmitted to the first wireless communication device. The first wireless communication device according to claim 1, which causes the device to transmit a response to the first physical layer protocol data unit in the same frame as the preemption instruction.

8. The one or more processors are further operable to execute the code individually or collectively, and the code is transmitted to the first wireless communication device. The first wireless communication device according to claim 7, wherein the first physical layer protocol data unit receives an instruction from a broadcast resource unit for transmitting the preemption instruction, and the preemption instruction is transmitted via the broadcast resource unit.

9. The one or more processors are further operable to execute the code individually or collectively, and the code is transmitted to the first wireless communication device. The first wireless communication device according to claim 1, wherein the second wireless communication device causes a frame to be received in response to the preemption instruction, and the transmission of the third physical layer protocol data unit is in response to the frame.

10. The one or more processors are further operable to execute the code individually or collectively, and the code is transmitted to the first wireless communication device. The first wireless communication device according to claim 1, wherein, based on the transmission of the preemption instruction, it causes a listen-before-talk procedure to be performed within a time period following the preemption instruction, wherein the transmission of the third physical layer protocol data unit is at least partially based on the listen-before-talk procedure, the duration of which is indicated to the first wireless communication device by the second wireless communication device, and the transmission of the third physical layer protocol data unit is within an allow duration indicated to the first wireless communication device by the second wireless communication device.

11. The aforementioned listen-before-talk procedure uses subslot granularity to determine the start time of the third physical layer protocol data unit. The sub-slot has a duration of less than 9 microseconds, according to the first wireless communication device of claim 10.

12. The first wireless communication device according to claim 1, wherein the third physical layer protocol data unit is transmitted within a time period corresponding to a second interframe space after the transmission of the preemption instruction.

13. The one or more processors are further operable to execute the code individually or collectively, and the code is transmitted to the first wireless communication device. The first wireless communication device according to claim 12, which causes the second wireless communication device to receive instructions for the duration of the second interframe space.

14. The one or more processors are further operable to execute the code individually or collectively, and the code is transmitted to the first wireless communication device. In the second interframe space of the transmission opportunity between the end time of the third physical layer protocol data unit and the scheduled start time for receiving the fourth physical layer protocol data unit from the second wireless communication device, the third wireless communication device receives a second preemption instruction associated with low latency data in the third wireless communication device, where the fourth physical layer protocol data unit is scheduled for reception within the transmission opportunity, and The first wireless communication device according to claim 1, wherein monitoring of the fourth physical layer protocol data unit is refrained from based at least in part on the second preemption instruction.

15. The one or more processors are further operable to execute the code individually or collectively, and the code is transmitted to the first wireless communication device. The first wireless communication device according to claim 14, wherein the second wireless communication device causes the second wireless communication device to receive a response frame for the third physical layer protocol data unit including a preemption permission instruction for the transmission opportunity, wherein the reception of the second preemption instruction is in response to the preemption permission instruction.

16. The one or more processors are further operable to execute the code individually or collectively, and the code is transmitted to the first wireless communication device. The first wireless communication device according to claim 1, wherein monitoring of the second physical layer protocol data unit is refrained from based at least in part on the preemption instruction.

17. The one or more processors are further operable to execute the code individually or collectively, and the code is transmitted to the first wireless communication device. The first wireless communication device according to claim 1, which receives scheduling information for scheduling the first physical layer protocol data unit and the second physical layer protocol data unit within the transmission opportunity.

18. The first wireless communication device is an access point, the second wireless communication device is a station, or The first wireless communication device according to claim 1, wherein the first wireless communication device is a station and the second wireless communication device is an access point.

19. The first wireless communication device according to claim 1, wherein the interframe space is one of a short interframe space, a point-coordination interframe space, or a competition window having random backoff.

20. A second wireless communication device, One or more memory locations for storing processor executable code, One or more processors coupled to the one or more memory, The device comprises one or more processors, and the second wireless communication device, In the interframe space between the end time of the first physical layer protocol data unit from the second wireless communication device and the scheduled start time of the second physical layer protocol data unit from the second wireless communication device, the first wireless communication device receives a preemption instruction associated with low latency data in the first wireless communication device, where the first physical layer protocol data unit and the second physical layer protocol data unit are scheduled within a transmission opportunity associated with the second wireless communication device, and A second wireless communication device that is capable of individually or collectively causing the first wireless communication device and at least partially based on the preemption instruction to receive a third physical layer protocol data unit, wherein the third physical layer protocol data unit is capable of executing the code to preempt the second physical layer protocol data unit within the transmission opportunity.

21. The one or more processors are further operable to execute the code individually or collectively, and the code is transmitted to the second wireless communication device. The second wireless communication device according to claim 20, wherein the first physical layer protocol data unit causes a preemption permission instruction for the transmission opportunity, wherein the reception of the preemption instruction is at least partially based on the preemption permission instruction.

22. The second wireless communication device according to claim 21, wherein the preemption permission instruction is included in one of the physical layer header of the first physical layer protocol data unit or the receiver address field of the first physical layer protocol data unit.

23. The one or more processors are further operable to execute the code individually or collectively, and the code is transmitted to the second wireless communication device. The second wireless communication device according to claim 20, wherein in the interframe space, the first wireless communication device receives a response frame for the first physical layer protocol data unit, and the reception of the preemption instruction occurs after the reception of the response frame.

24. The one or more processors are further operable to execute the code individually or collectively, and the code is transmitted to the second wireless communication device. The second wireless communication device according to claim 20, which causes the first wireless communication device to issue a response frame to the first physical layer protocol data unit in the same frame as the preemption instruction.

25. The one or more processors are further operable to execute the code individually or collectively, and the code is transmitted to the second wireless communication device. The second wireless communication device according to claim 24, wherein the first physical layer protocol data unit causes a broadcast resource unit to transmit the preemption instruction, and the preemption instruction is received via the broadcast resource unit.

26. The one or more processors are further operable to execute the code individually or collectively, and the code is transmitted to the second wireless communication device. The second wireless communication device according to claim 20, wherein a frame is transmitted in response to the preemption instruction, and the reception of the third physical layer protocol data unit is in response to the frame.

27. The one or more processors are further operable to execute the code individually or collectively, and the code is transmitted to the second wireless communication device. In the second interframe space of the transmission opportunity between the end time of the third physical layer protocol data unit and the scheduled start time for receiving the fourth physical layer protocol data unit from the second wireless communication device, the third wireless communication device receives a second preemption instruction associated with low latency data in the third wireless communication device, where the fourth physical layer protocol data unit is scheduled for reception within the transmission opportunity, and The second wireless communication device according to claim 20, wherein the third wireless communication device causes a fifth physical layer protocol data unit to be received from the third wireless communication device and at least in part based on the second preemption instruction, wherein the fifth physical layer protocol data unit preempts the fourth physical layer protocol data unit within the transmission opportunity.

28. The one or more processors are further operable to execute the code individually or collectively, and the code is transmitted to the second wireless communication device. The second wireless communication device according to claim 27, wherein it causes the third physical layer protocol data unit to transmit a response frame including a preemption permission instruction for the transmission opportunity, wherein the reception of the second preemption instruction is in response to the preemption permission instruction.

29. A method for wireless communication in a first wireless communication device, In the interframe space between the end time of the first physical layer protocol data unit from the second wireless communication device and the scheduled start time of the second physical layer protocol data unit from the second wireless communication device, a preemption instruction associated with low latency data is transmitted in the first wireless communication device, where the first physical layer protocol data unit and the second physical layer protocol data unit are scheduled within a transmission opportunity associated with the second wireless communication device. A method comprising transmitting a third physical layer protocol data unit that preempts the second physical layer protocol data unit within the transmission opportunity, at least in part based on the preemption instruction.

30. A method for wireless communication in a second wireless communication device, In the interframe space between the end time of the first physical layer protocol data unit from the second wireless communication device and the scheduled start time of the second physical layer protocol data unit from the second wireless communication device, the first wireless communication device receives a preemption instruction associated with low latency data in the first wireless communication device, where the first physical layer protocol data unit and the second physical layer protocol data unit are scheduled within a transmission opportunity associated with the second wireless communication device. A method comprising receiving from the first wireless communication device and a third physical layer protocol data unit that preempts the second physical layer protocol data unit within the transmission opportunity, at least in part based on the preemption instruction.

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