Traffic management during limited target wake time (TWT) service periods

Abstract

The present disclosure provides a system, method, and apparatus, including a computer program encoded on a computer storage medium, for managing data traffic in a restricted target wake time (TWT) service period (SP). In some aspects, an access point (AP) may transmit a packet when a restricted TWT SP begins, signaling all non-member wireless stations (STAs) to postpone access to the wireless medium for at least a threshold duration. Upon receiving the packet, any non-member STAs associated with the AP may set their network allocation vector (NAV) according to the duration indicated by the duration field of the received packet. In some implementations, low-latency STAs that are members of the TWT SP may not set their NAV according to the duration field of the received packet. Instead, the low-latency STAs may access the wireless medium before the NAV associated with the non-member STAs expires.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This patent application claims priority to commonly assigned U.S. patent application Ser. No. 17 / 402,391, entitled "TRAFFIC MANAGEMENT IN RESTRICTED TARGET WAKE TIME (TWT) SERVICE PERIODS," filed Aug. 13, 2021. The disclosures of all prior applications are deemed to be part of, and are incorporated by reference into, this patent application.

[0002] FIELD OF THE DISCLOSURE

[0002] The present disclosure relates generally to wireless communications, and more specifically, to managing data traffic during bounded target wake time (TWT) service periods. [Background technology]

[0003]

[0003] A wireless local area network (WLAN) may be formed by one or more access points (APs) that provide a shared wireless medium for use by several client devices or stations (STAs). Each AP, which may support a Basic Service Set (BSS), may periodically broadcast a beacon frame to enable any STA within wireless range of the AP to establish and maintain a communication link with the WLAN. WLANs that operate according to the IEEE 802.11 family of standards are commonly referred to as Wi-Fi networks.

[0004]

[0004] Some wireless communication devices may be associated with low-latency applications that have strict end-to-end latency, throughput, and timing requirements for data traffic. Exemplary low-latency applications include, but are not limited to, real-time gaming applications, video communications, and augmented reality (AR) and virtual reality (VR) applications (collectively referred to as extended reality (XR) applications). Such low-latency applications may specify various latency, throughput, and timing requirements for wireless communication systems that provide connectivity to these applications. It is therefore desirable to ensure that a WLAN can meet the various latency, throughput, and timing requirements of such low-latency applications. Summary of the Invention

[0005]

[0005] The systems, methods, and devices of the present disclosure each have several innovative aspects, no single aspect of which is solely responsible for the desirable properties disclosed herein.

[0006]

[0006] One innovative aspect of the subject matter described in this disclosure may be implemented as a method of wireless communication. The method may be executed by a wireless communication device to manage data traffic in a restricted target wake time (TWT) service period (SP). In some implementations, the method may include performing a channel sensing operation indicating whether a wireless channel is busy or idle, and transmitting a first packet over the wireless channel at a first time in response to the channel sensing operation indicating that the wireless channel associated with the restricted TWT SP is idle for a threshold duration relative to a start of the restricted TWT SP, the first packet including a duration field indicating a duration for which the wireless channel is reserved, and the channel sensing operation further indicates that the wireless channel is busy at a second time after the first time less than the duration indicated by the duration field of the first packet.

[0007] Another innovative aspect of the subject matter described in this disclosure may be implemented in a wireless communication device. The wireless communication device may include a processing system configured to perform a channel sensing operation indicating whether a wireless channel is busy or idle, and at least one interface, the at least one interface configured to transmit a first packet over the wireless channel in response to the channel sensing operation indicating, at a first time, that the wireless channel associated with the restricted TWT SP is idle for a threshold duration relative to a start of the restricted TWT SP, the first packet including a duration field indicating a duration for which the wireless channel is reserved, and the channel sensing operation further indicating that the wireless channel is busy at a second time after the first time less than the duration indicated by the duration field of the first packet.

[0008] Another innovative aspect of the subject matter described in this disclosure may be implemented as a method of wireless communication. The method may be executed by a wireless communication device to manage data traffic in a restricted TWT SP. In some implementations, the method may include receiving, at a first time, a first packet over a wireless channel associated with the restricted TWT SP, the first packet including a duration field indicating a duration for which the wireless channel is reserved, and transmitting, at a second time, a second packet over the wireless channel in response to the first packet, the second packet being less than the duration indicated by the duration field of the first packet after the first time.

[0009] Another innovative aspect of the subject matter described in this disclosure may be implemented in a wireless communication device. The wireless communication device may include a processing system and an interface, where the interface is configured to receive, at a first time, over a wireless channel associated with a restricted TWT SP, a first packet including a duration field indicating a duration for which the wireless channel is reserved, and at a second time, in response to the first packet, over the wireless channel, a second packet that is less than the duration indicated by the duration field of the first packet after the first time.

[0010]

[0010] Details of one or more implementations of the subject matter described in this disclosure are set forth in the accompanying drawings and the following description. Other features, aspects, and advantages will become apparent from the description, drawings, and claims. Please note that the relative dimensions of the following figures may not be drawn to scale. [Brief description of the drawings]

[0011] [Figure 1]

[0011] A block diagram of an exemplary wireless system is shown. [Diagram 2]

[0012] 1 shows a block diagram of an exemplary wireless station (STA). [Diagram 3]

[0013] 1 shows a block diagram of an exemplary access point (AP). [Figure 4A]

[0014] 1 illustrates a timing diagram illustrating an example of wireless communication between devices belonging to a basic service set (BSS). [Figure 4B]

[0015] 1 shows a timing diagram illustrating an example of wireless communication between devices belonging to a BSS. [Figure 4C]

[0016] 1 shows a timing diagram illustrating an example of wireless communication between devices belonging to a BSS. [Diagram 5]

[0017] 1 shows a timing diagram illustrating an example of wireless communication between devices belonging to a BSS. [Figure 6]

[0018] 1 shows a timing diagram illustrating an example of wireless communication between devices belonging to a BSS. [Figure 7]

[0019] 1 shows a timing diagram illustrating an example of wireless communication between devices belonging to a BSS. [Figure 8A]

[0020] 1 shows a timing diagram illustrating an example of wireless communication between devices belonging to a BSS. [Figure 8B]

[0021] 1 shows a timing diagram illustrating an example of wireless communication between devices belonging to a BSS. [Figure 9A]

[0022] 1 shows a timing diagram illustrating an example of wireless communication between devices belonging to a BSS. [Figure 9B]

[0023] 1 shows a timing diagram illustrating an example of wireless communication between devices belonging to a BSS. [Figure 10A]

[0024] 1 shows a timing diagram illustrating an example of wireless communication between devices belonging to a BSS. [Figure 10B]

[0025] 1 shows a timing diagram illustrating an example of wireless communication between devices belonging to a BSS. [Figure 11A]

[0026] 1 shows a timing diagram illustrating an example of wireless communication between devices belonging to a BSS. [Figure 11B]

[0027] 1 shows a timing diagram illustrating an example of wireless communication between devices belonging to a BSS. [Figure 12]

[0028] 1 shows an illustrative flow chart illustrating an exemplary wireless communication operation. [Figure 13]

[0029] 1 shows an illustrative flow chart illustrating an exemplary wireless communication operation. [Figure 14]

[0030] 1 illustrates a block diagram of an exemplary wireless communication device. [Figure 15]

[0031] 1 illustrates a block diagram of an exemplary wireless communication device.

[0012]

[0032] Like reference numbers and designations in the various drawings indicate like elements. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013]

[0033] The following description is directed to some specific implementations for purposes of illustrating the innovative aspects of the present disclosure. However, those skilled in the art will readily recognize that the teachings herein can be applied in many different ways. The described implementations can be implemented in any device, system, or network capable of transmitting and receiving radio frequency (RF) signals according to one or more of the Long Term Evolution (LTE), 3G, 4G, or 5G (New Radio (NR)) standards promulgated by the 3rd Generation Partnership Project (3GPP), the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard, the IEEE 802.15 standard, or the Bluetooth standard defined by the Bluetooth Special Interest Group (SIG), among others. The described implementations may 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), frequency division multiple access (FDMA), orthogonal FDMA (OFDMA), single-carrier FDMA (SC-FDMA), single-user (SU) multiple-input multiple-output (MIMO), and multi-user (MU) MIMO.The described implementations may also be implemented using other wireless communications protocols or RF signals suitable for use in one or more of a wireless wide area network (WWAN), a wireless personal area network (WPAN), a wireless local area network (WLAN), or an internet of things (IOT) network.

[0014]

[0034] Many wireless networks use a random channel access mechanism to control access to a shared wireless medium. In these wireless networks, wireless communication devices (including access points (APs) and wireless stations (STAs)) compete with each other using carrier sense multiple access / collision avoidance (CSMA / CA) techniques to gain access to the wireless medium. Generally, the wireless communication device that randomly selects the lowest back-off number (RBO) wins the medium access contention operation and may be granted access to the wireless medium for a period of time generally referred to as a transmit opportunity (TXOP). Other wireless communication devices are generally not allowed to transmit during the TXOP of another wireless communication device to avoid collisions on the shared wireless medium.

[0015]

[0035] Some random channel access mechanisms, such as enhanced distributed channel access (EDCA), give high priority traffic a greater chance of gaining medium access than low priority traffic. EDCA classifies data into different access categories (ACs), such as voice (AC_VO), video (AC_VI), best effort (AC_BE), and background (AC_BK). Each AC is associated with a different priority level and may be assigned a different range of RBOs such that higher priority data is more likely to win a TXOP than lower priority data (e.g., by assigning a lower RBO to higher priority data and a higher RBO to lower priority data). Although EDCA increases the likelihood that low latency data traffic will gain access to the shared wireless medium during a given contention period, the unpredictable outcome of medium access contention behavior may prevent low latency applications from achieving a certain level of throughput or meeting certain latency requirements.

[0016]

[0036] The IEEE 802.11be amendment to the IEEE 802.11 standard describes a restricted target wake time (TWT) service period (SP) that may be used to provide more predictable latency, reduced worst-case latency, or reduced jitter with greater reliability for latency-sensitive traffic. As used herein, the term "non-legacy STA" may refer to any STA that supports restricted TWT operation, and the term "low latency STA" may refer to any non-legacy STA that has latency-sensitive traffic to transmit or receive. In contrast, the term "legacy STA" may refer to any STA that does not support restricted TWT operation. The IEEE 802.11be amendment requires that all non-legacy STAs that are TXOP holders outside of a restricted TWT SP end their respective TXOP before the start of any restricted TWT SP of which they are not a member. Although membership in a restricted TWT SP is reserved for low-latency STAs, the current rules for restricted TWT SP do not prevent non-member STAs from obtaining a TXOP during the restricted TWT SP. As a result, some non-member STAs may gain access to the shared wireless medium during the restricted TWT SP, even before the members of the SP. Therefore, a new communication protocol or mechanism is needed to further protect latency-sensitive traffic in the restricted TWT SP.

[0017]

[0037] Implementations of the subject matter described in this disclosure may be used to manage data traffic in a restricted TWT SP. In some aspects, the AP may transmit a packet at the beginning of a restricted TWT SP explicitly signaling all non-member STAs to postpone access to the wireless medium for at least a threshold duration. For example, the threshold duration may be indicated by a duration field in the medium access control (MAC) header of the packet. Upon receiving the packet, any non-member STAs associated with the AP may set their network allocation vector (NAV) according to the duration indicated by the duration field. In some implementations, the packet may be a trigger frame requesting a trigger-based (TB) physical layer convergence protocol (PLCP) protocol data unit (PDU) (PPDU) from one or more low latency STAs. In some other implementations, the header packet may be a clear-to-send (CTS) frame to self. In such implementations, any low-latency STAs that are members of the TWT SP may ignore the CTS-to-self frame. In other words, the low-latency STAs may not set their NAV according to the duration indicated by the duration field of the CTS-to-self frame. Furthermore, in some implementations, the packet may be a multi-user (MU) request-to-send (RTS) frame that identifies one or more low-latency STAs. In such implementations, each low-latency STA identified by the MU-RTS may transmit a CTS frame in response to the MU-RTS frame without setting its NAV according to the duration field of the MU-RTS frame.

[0018]

[0038] In some other aspects, non-legacy STAs that are not members of the restricted TWT SP may be required (such as through implicit signaling) to postpone access to the wireless medium for at least a threshold duration at the start of the restricted TWT SP. In some implementations, non-legacy STAs may be required to reset their RBOs at the start of the restricted TWT SP. Thus, each non-legacy STA (including low latency STAs that are members of the SP as well as non-member STAs) that have data to transmit or receive at the start of the restricted TWT SP must contend for medium access from the start of the restricted TWT SP. In some other implementations, non-legacy STAs may be required to postpone access to the shared wireless medium for the duration of the restricted TWT SP. Thus, any non-member STAs that have data to transmit or receive during the restricted TWT SP must refrain from accessing the shared wireless medium until after the restricted TWT SP ends. Still further, in some aspects, the AP may throttle traffic from all non-legacy STAs that are not members of the restricted TWT SP for at least a threshold duration at the start of the restricted TWT SP. For example, the AP may broadcast a beacon frame including a quietness element indicating a quietness duration associated with the restricted TWT SP. After receiving such a beacon frame, any non-member STA that has data to transmit or receive during the restricted TWT SP must postpone access to the shared wireless medium for at least the quietness duration indicated in the beacon frame.

[0019]

[0039] Particular implementations of the subject matter described in this disclosure may be implemented to achieve one or more of the following potential advantages: By requiring non-member STAs, through explicit or implicit signaling, to defer medium access for a threshold duration at the start of a restricted TWT, aspects of the present disclosure may significantly improve the latency gain achievable by latency-sensitive traffic through application of a restricted TWT SP. For example, under current rules for a restricted TWT SP, a non-member STA that is already in the process of counting down its RBO at the start of a restricted TWT SP may gain access to the shared wireless medium before any low-latency STAs that are members of the SP. However, the additional requirements imposed on non-member STAs (through the signaling techniques of the present disclosure) may protect low-latency STAs from losing medium access at the start of a restricted TWT SP. Thus, aspects of the present disclosure may ensure that latency-sensitive traffic is prioritized over all other traffic during a restricted TWT SP. As a result, the constrained TWT SP may provide more predictable latency, reduced worst-case latency, or reduced jitter, along with higher reliability for latency-sensitive traffic.

[0020]

[0040] FIG. 1 shows a block diagram of an exemplary wireless system 100. The wireless system 100 is illustrated to include a wireless access point (AP) 110 and several wireless stations (STAs) 120a-120i. For simplicity, only one AP 110 is illustrated in FIG. 1. The AP 110 may form a wireless local area network (WLAN) that allows the AP 110, the STAs 120a-120i, and other wireless devices (not shown for simplicity) to communicate with each other over a wireless medium. The wireless medium, which may be divided into several channels or into several resource units (RUs), may facilitate wireless communication between the AP 110, the STAs 120a-120i, and other wireless devices connected to the WLAN. In some implementations, the STAs 120a-120i may communicate with each other using peer-to-peer communication (e.g., without the presence or involvement of the AP 110). The AP 110 is assigned a unique MAC address that is programmed therein, for example, by the access point's manufacturer. Similarly, each of the STAs 120a-120i may also be assigned a unique MAC address.

[0021]

[0041] In some implementations, the wireless system 100 may correspond to a multiple-input multiple-output (MIMO) wireless network and may support single-user MIMO (SU-MIMO) and multi-user (MU-MIMO) communications. In some implementations, the wireless system 100 may support orthogonal frequency division multiple access (OFDMA) communications. Although the WLAN is illustrated in FIG. 1 as an infrastructure basic service set (BSS), in other implementations, the WLAN may be an independent basic service set (IBSS), an extended service set (ESS), an ad-hoc network, or a peer-to-peer (P2P) network (such as operating according to one or more Wi-Fi Direct protocols).

[0022]

[0042] The STAs 120a-120i may be any suitable Wi-Fi enabled wireless device including, for example, a mobile phone, a personal digital assistant (PDA), a tablet device, a laptop computer, or the like. The STAs 120a-120i may also be referred to as user equipment (UE), subscriber stations, mobile units, subscriber units, wireless units, remote units, mobile devices, wireless devices, wireless communications devices, remote devices, mobile subscriber stations, access terminals, mobile terminals, wireless terminals, remote terminals, handsets, user agents, mobile clients, clients, or some other suitable terminology.

[0023]

[0043] The AP 110 may be any suitable device that enables one or more wireless devices (such as the STAs 120a-120i) to connect to a network (such as a local area network (LAN), a wide area network (WAN), a metropolitan area network (MAN), or the Internet). In some implementations, the system controller 130 may facilitate communications between the AP 110 and other networks or systems. In some implementations, the system controller 130 may facilitate communications between the AP 110 and one or more other APs (not shown for simplicity) that may be associated with other wireless networks. Additionally or alternatively, the AP 110 may exchange signals and information with one or more other APs using wireless communications.

[0024]

[0044] The AP 110 may periodically broadcast beacon frames to enable the STAs 120a-120i and other wireless devices within wireless range of the AP 110 to establish and maintain communication links with the AP 110. The beacon frames, which indicate downlink (DL) data transmissions to the STAs 120a-120i and may request or schedule uplink (UL) data transmissions from the STAs 120a-120i, are typically broadcast according to a target beacon transmission time (TBTT) schedule. The broadcasted beacon frames may include a timing synchronization function (TSF) value of the AP 110. The STAs 120a-120i may, for example, synchronize their own local TSF values ​​with the broadcasted TSF value such that all of the STAs 120a-120i are synchronized with each other and with the AP 110.

[0025]

[0045] In some implementations, each of the stations STAs 120a-120i and the AP 110 may include one or more transceivers, one or more processing resources (processors or application specific integrated circuits (ASICs)), one or more memory resources, and a power source (such as a battery). The one or more transceivers may include a Wi-Fi transceiver, a Bluetooth transceiver, a cellular transceiver, or other suitable radio frequency (RF) transceiver (not shown for simplicity) for transmitting and receiving wireless communication signals. In some implementations, each transceiver may communicate with other wireless devices in distinct frequency bands and / or using distinct communication protocols. The memory resources may include a non-transitory computer-readable medium (such as one or more non-volatile memory elements, such as an EPROM, an EEPROM, a flash memory, a hard drive, etc.) that stores instructions for performing one or more operations described with respect to FIGS. 5-11.

[0026]

[0046] FIG. 2 illustrates a block diagram of an exemplary wireless station (STA) 200. The STA 200 may be an implementation of at least one of the STAs 120a-120i of FIG. 1. The STA 200 may include one or more transceivers 210, a processor 220, a user interface 230, a memory 240, and a number of antennas ANT1-ANTn. The transceiver 210 may be coupled to the antennas ANT1-ANTn either directly or through an antenna selection circuit (not shown for simplicity). The transceiver 210 may be used to transmit signals to and receive signals from other wireless devices, including, for example, a number of APs and a number of other STAs. Although not shown in FIG. 2 for simplicity, the transceiver 210 may include any number of transmit chains to process signals and transmit signals to other wireless devices via the antennas ANT1-ANTn, and any number of receive chains to process signals received from the antennas ANT1-ANTn. Thus, the STA 200 may be configured for MIMO and OFDMA communications. The MIMO communication may include SU-MIMO communication and MU-MIMO communication. In some implementations, the STA 200 may use multiple antennas ANT1 to ANTn to provide antenna diversity. The antenna diversity may include polarization diversity, pattern diversity, and spatial diversity.

[0027]

[0047] The processor 220 may be any suitable processor or processors capable of executing scripts or instructions of one or more software programs stored in the STA 200 (e.g., in the memory 240). In some implementations, the processor 220 may be or include one or more microprocessors providing processor functionality and an external memory providing at least a portion of the machine-readable medium. In other implementations, the processor 220 may be or include an Application Specific Integrated Circuit (ASIC) with the processor, bus interface, user interface, and at least a portion of the machine-readable medium integrated on a single chip. In some other implementations, the processor 220 may be or include one or more Field Programmable Gate Arrays (FPGAs) or Programmable Logic Devices (PLDs).

[0028]

[0048] In some implementations, the processor 220 may be a component of a processing system. A processing system may generally refer to a system or set of machines or components that receives inputs, processes the inputs, and generates a set of outputs (e.g., that may be passed to other systems or components of the STA 200). For example, the processing system of the STA 200 may refer to a system that includes various other components or subcomponents of the STA 200.

[0029]

[0049] The processing system of the STA 200 may interface with other components of the STA 200 and may process information (e.g., input or signal) received from the other components, output information to the other components, etc. For example, the chip or modem of the STA 200 may be coupled to or include a processing system, a first interface for outputting information, and a second interface for acquiring information. In some cases, the first interface may refer to an interface between the processing system and a transmitter of the chip or modem such that the STA 200 may transmit information output from the chip or modem. In some cases, the second interface may refer to an interface between the processing system and a receiver of the chip or modem such that the STA 200 may acquire information or signal input and information may be passed to the processing system. Those skilled in the art will readily recognize that the first interface may also acquire information or signal input and the second interface may also output information or signal output.

[0030]

[0050] The user interface 230 coupled to the processor 220 may be or represent a number of suitable user input devices, such as, for example, a speaker, a microphone, a display device, a keyboard, a touch screen, etc. In some implementations, the user interface 230 may enable a user to control certain operations of the STA 200 to interact with one or more applications executable by the STA 200, and other suitable functions.

[0031]

[0051] In some implementations, the STA 200 may include a satellite positioning system (SPS) receiver 250. The SPS receiver 250, coupled to the processor 220, may be used to acquire and receive signals transmitted from one or more satellites or satellite systems via an antenna (not shown for simplicity). The signals received by the SPS receiver 250 may be used to determine (or at least aid in determining) the location of the STA 200.

[0032]

[0052] The memory 240 may include a device database 241 that may store location data, configuration information, data rates, medium access control (MAC) addresses, timing information, modulation and coding schemes (MCS), traffic indication (TID) queue sizes, ranging capabilities, and other suitable information for (or related to) the STA 200. The device database 241 may also store profile information for several other wireless devices. The profile information for a given wireless device may include, for example, the service set identification (SSID), Basic Service Set Identifier (BSSID), operating channel, TSF value, beacon interval, ranging schedule, channel state information (CSI), received signal strength indicator (RSSI) value, goodput value, and connection history with the STA 200 for the wireless device. In some implementations, the profile information for a given wireless device may also include a clock offset value, a carrier frequency offset value, and ranging capabilities.

[0033]

[0053] Memory 240 may also be or include a non-transitory computer-readable storage medium (such as one or more non-volatile memory elements, such as EPROM, EEPROM, flash memory, a hard drive, etc.) that may store computer-executable instructions 242 for performing all or a portion of one or more operations described in this disclosure.

[0034]

[0054] FIG. 3 illustrates a block diagram of an exemplary access point (AP) 300. The AP 300 may be one implementation of the AP 110 of FIG. 1. The AP 300 may include one or more transceivers 310, a processor 320, a memory 330, a network interface 340, and a number of antennas ANT1-ANTn. The transceiver 310 may be coupled to the antennas ANT1-ANTn either directly or through an antenna selection circuit (not shown for simplicity). The transceiver 310 may be used to transmit signals to and receive signals from other wireless devices, including, for example, one or more of the STAs 120a-120i and other APs of FIG. 1. Although not shown in FIG. 3 for simplicity, the transceiver 310 may include any number of transmit chains to process signals and transmit signals to other wireless devices via the antennas ANT1-ANTn, and any number of receive chains to process signals received from the antennas ANT1-ANTn. Thus, the AP 300 may be configured for MIMO and OFDMA communications. The MIMO communication may include SU-MIMO communication and MU-MIMO communication. In some implementations, the AP 300 may use multiple antennas ANT1 to ANTn to provide antenna diversity. The antenna diversity may include polarization diversity, pattern diversity, and spatial diversity.

[0035]

[0055] In high frequency (such as 60 GHz or millimeter wave (mmWave)) wireless communication systems (such as those conforming to the IEEE 802.11ad or 802.11ay amendments of the IEEE 802.11 standard), communications may be beamformed using phased array antennas at the transmitter and receiver. Beamforming generally refers to a wireless communication technique in which the transmitting and receiving devices adjust transmit or receive antenna settings to achieve a desired link budget for subsequent communications. A procedure for adapting the transmit and receive antennas, called beamforming training, may be performed initially to establish a link between the transmitting and receiving devices, and may be performed periodically to maintain a quality link using optimized transmit and receive beams.

[0036]

[0056] The processor 320 may be any suitable processor or processors capable of executing scripts or instructions of one or more software programs stored in the AP 300 (e.g., in the memory 330). In some implementations, the processor 320 may be or include one or more microprocessors providing processor functionality and an external memory providing at least a portion of the machine-readable medium. In other implementations, the processor 320 may be or include an ASIC with the processor, bus interface, user interface, and at least a portion of the machine-readable medium integrated into a single chip. In some other implementations, the processor 320 may be or include one or more FPGAs or PLDs. In some implementations, the processor 320 may be a component of a processing system. For example, the processing system of the AP 300 may refer to a system that includes various other components or subcomponents of the AP 300.

[0037]

[0057] The processing system of the AP 300 may interface with other components of the AP 300 and may process information (such as input or signals) received from other components, output information to other components, etc. For example, a chip or modem of the AP 300 may include a processing system, a first interface for outputting information, and a second interface for acquiring information. In some cases, the first interface may refer to an interface between the processing system of the chip or modem and a transmitter, such that information output from the chip or modem may be transmitted to the AP 300. In some cases, the second interface may refer to an interface between the processing system of the chip or modem and a receiver, such that the AP 300 may acquire information or signal input and information may be passed to the processing system. Those skilled in the art will readily recognize that the first interface may also acquire information or signal input and the second interface may also output information or signal output.

[0038]

[0058] A network interface 340, coupled to the processor 320, may be used to communicate with the system controller 130 of Figure 1. The network interface 340 may also enable the AP 300 to communicate with other wireless systems, other APs, one or more backhaul networks, or any combination thereof, either directly or through one or more intervening networks.

[0039]

[0059] The memory 330 may include a device database 331 that may store location data, configuration information, data rates, MAC addresses, timing information, MCS, ranging capabilities, and other suitable information for (or regarding) the AP 300. The device database 331 may also store profile information for several other wireless devices (such as one or more of the stations 120a-120i of FIG. 1). The profile information for a given wireless device may include, for example, the SSID, BSSID, operating channel, CSI, received signal strength indicator (RSSI) value, goodput value, and connection history with the AP 300 for the wireless device. In some implementations, the profile information for a given wireless device may also include a TID queue size, a preferred packet duration for trigger-based UL transmissions, and a maximum amount of queued UL data that the wireless device may insert into a TB PPBU.

[0040]

[0060] The memory 330 may also be or include a non-transitory computer-readable storage medium (such as one or more non-volatile memory elements, such as EPROM, EEPROM, flash memory, hard drive, etc.) that may store computer-executable instructions 332 for performing all or a portion of one or more operations described in this disclosure.

[0041]

[0061] FIG. 4A illustrates a timing diagram 400 showing an example of wireless communication between devices belonging to a BSS. In the example of FIG. 4A, the BSS is shown to include a low-latency STA 402 and a non-legacy STA 404. The low-latency STA 402 is a member of a restricted TWT SP (r-TWT SP) for a duration from time t3 to t8, while the non-legacy STA 404 is not a member of the restricted TWT SP (and thus may be referred to as a "non-member STA"). In some implementations, each of the STAs 402 and 404 may be an example of any of the STAs 120a-120i of FIG. 1 or the STA 200 of FIG. 2. Although only one low-latency STA and one non-legacy STA are shown in the example of FIG. 4A, in an actual implementation, the BSS may include any number of low-latency STAs and any number of non-legacy STAs.

[0042]

[0062] The non-legacy STA 404 attempts to access the shared wireless medium before the start of the restricted TWT SP. More specifically, the non-legacy STA 404 senses that the medium is idle for a threshold duration from time t0 to t1 based on a channel sensing operation (such as clear channel assessment (CCA)), and further counts down a random backoff (RBO) duration from time t1 to t2 before attempting to acquire a TXOP. For example, the threshold duration (from time t0 to t1) may be an arbitration interframe spacing (AIFS) duration associated with a particular access category (AC) of data traffic. Thus, the RBO duration (from time t1 to t2) may be randomly selected from a range of RBOs spanning a contention window associated with the AC. At time t2, the non-legacy STA 404 senses that the wireless medium is still idle and proceeds to acquire a TXOP, for example, by starting transmission over the shared medium. However, existing rules regarding restricted TWT operation require that non-member STAs terminate their TXOP with the start of a restricted TWT SP. Since the restricted TWT SP in FIG. 4A starts at time t3, the non-legacy STA 404 must shorten its TXOP between times t2 and t3.

[0043]

[0063] The low-latency STA 402 attempts to access the shared wireless medium at the beginning of the restricted TWT SP. More specifically, the low-latency STA 402 senses the medium to be idle for the AIFS duration from time t3 to t4, and further counts down the RBO duration from time t4 to t6 before attempting to acquire a TXOP. In the example of FIG. 4A, the non-legacy STA 404 also attempts to access the shared wireless medium at the beginning of the restricted TWT SP. For example, the non-legacy STA 404 senses the medium to be idle for the AIFS duration from time t3 to t5, and further counts down the RBO duration beginning at time t5. In some implementations, the data traffic associated with the low-latency STA 402 may be assigned to a higher priority AC than the data traffic associated with the non-legacy STA 404. Thus, the AIFS or RBO duration associated with the low-latency STA 402 may be shorter than the AIFS or RBO duration associated with the non-legacy STA 404, respectively. As a result, the low latency STA 402 wins access to the wireless medium at time t6 and obtains a TXOP, eg, by initiating transmission over the shared medium.

[0044]

[0064] At time t6, the non-legacy STA 404 senses that the wireless medium is busy and refrains from accessing the shared medium for the duration of the TXOP. After the TXOP ends, at time t7, the non-legacy STA 404 may once again attempt to access the wireless medium. In this manner, the restricted TWT operation may prioritize latency-sensitive traffic within the BSS, for example, by requiring other non-legacy STAs to end their TXOPs by initiating the restricted TWT SP. Furthermore, the AP (not shown for simplicity) may throttle traffic from all legacy STAs associated with the BSS by scheduling a quiet interval to overlap with the restricted TWT SP. For example, the duration of the quiet interval may be indicated by one or more quiet elements included in management frames (such as beacon and probe response frames) transmitted by the AP prior to the start of the restricted TWT SP.

[0045]

[0065] FIG. 4B illustrates a timing diagram 410 showing an example of wireless communication between devices belonging to a BSS. In the example of FIG. 4B, the BSS is shown to include a low-latency STA 412 and a non-legacy STA 414. The low-latency STA 412 is a member of a restricted TWT SP (r-TWT SP) for a duration from time t2 to t6, while the non-legacy STA 414 is not a member of the restricted TWT SP (and thus may be referred to as a "non-member STA"). In some implementations, each of the STAs 412 and 414 may be an example of any of the STAs 120a-120i of FIG. 1 or the STA 200 of FIG. 2. Although only one low-latency STA and one non-legacy STA are shown in the example of FIG. 4B, in an actual implementation, the BSS may include any number of low-latency STAs and any number of non-legacy STAs.

[0046]

[0066] The non-legacy STA 414 attempts to access the shared wireless medium before the start of the restricted TWT SP. More specifically, the non-legacy STA 414 senses that the medium is idle for the AIFS duration from time t0 to t1, and further counts down the RBO duration from time t1 to t4 before attempting to acquire a TXOP. In the example of FIG. 4B, the RBO duration randomly selected by the non-legacy STA 414 is greater than the amount of time (from time t1 to t2) remaining before the start of the restricted TWT SP. However, existing rules regarding restricted TWT operation do not prevent the RBO countdown from extending beyond the start of the restricted TWT SP. At time t4, the non-legacy STA 414 senses that the wireless medium is still idle and proceeds to acquire a TXOP, for example, by starting transmission over the shared wireless medium. As a result, the non-legacy STA 414 gains access to the shared wireless medium from time t4 to t5 during the restricted TWT SP. Since the non-legacy STA 414 does not obtain its TXOP before the start of the restricted TWT SP, the TXOP (from time t4 to t5) does not violate any existing rules regarding restricted TWT operation.

[0047]

[0067] The low-latency STA 412 attempts to access the shared wireless medium at the start of the restricted TWT SP. More specifically, the low-latency STA 412 senses the medium to be idle for the AIFS duration from time t2 to t3, and further counts down the RBO duration beginning at time t3. In some implementations, the data traffic associated with the low-latency STA 412 may be assigned to a higher priority AC than the data traffic associated with the non-legacy STA 414. Thus, the AIFS or RBO duration associated with the low-latency STA 412 may be shorter than the AIFS or RBO duration associated with the non-legacy STA 414, respectively. However, since the non-legacy STA 414 started its RBO countdown before the start of the restricted TWT SP, the non-legacy STA 414 may obtain a TXOP before the low-latency STA 412 completes its RBO countdown. As a result, the low-latency STA 412 senses that the wireless medium is busy at time t4 and refrains from accessing the shared wireless medium for the duration of the TXOP of the non-legacy STA 414. After the TXOP ends, at time t5, the low-latency STA 412 may once again attempt to access the wireless medium.

[0048]

[0068] FIG. 4C illustrates a timing diagram 420 showing an example of wireless communication between devices belonging to a BSS. In the example of FIG. 4C, the BSS is shown to include a low-latency STA 422 and a non-legacy STA 424. The low-latency STA 422 is a member of a restricted TWT SP (r-TWT SP) for a duration from time t3 to t7, while the non-legacy STA 424 is not a member of the restricted TWT SP (and thus may be referred to as a "non-member STA"). In some implementations, each of the STAs 422 and 424 may be an example of any of the STAs 120a-120i of FIG. 1 or the STA 200 of FIG. 2. Although only one low-latency STA and one non-legacy STA are shown in the example of FIG. 4C, in an actual implementation, the BSS may include any number of low-latency STAs and any number of non-legacy STAs.

[0049]

[0069] The non-legacy STA 424 attempts to access the shared wireless medium before the start of the restricted TWT SP. More specifically, the non-legacy STA 424 senses that the medium is idle for the AIFS duration from time t0 to t1, and further counts down the RBO duration from time t1 to t2 before attempting to acquire a TXOP. In the example of FIG. 4C, the RBO countdown ends (at time t2) before the start of the restricted TWT SP. However, the non-legacy STA 424 may determine that the duration between the end of the RBO countdown and the start of the restricted TWT SP (from time t2 to t3) is not appropriate for the (shortened) TXOP. Thus, in some implementations, the non-legacy STA 424 may perform a new RBO countdown from time t2 to t5. At time t5, the non-legacy STA 424 senses that the wireless medium is still idle and proceeds to acquire a TXOP, e.g., by starting transmission over the shared wireless medium. As a result, the non-legacy STA 424 gains access to the shared wireless medium from time t5 to t6 during the restricted TWT SP. Because the non-legacy STA 424 does not obtain its TXOP before the start of the restricted TWT SP, the TXOP (from time t5 to t6) does not violate any existing rules regarding restricted TWT operation.

[0050]

[0070] The low-latency STA 422 attempts to access the shared wireless medium at the start of the restricted TWT SP. More specifically, the low-latency STA 422 senses the medium to be idle for the AIFS duration from time t3 to t4, and further counts down the RBO duration beginning at time t4. In some implementations, the data traffic associated with the low-latency STA 422 may be assigned to a higher priority AC than the data traffic associated with the non-legacy STA 424. Thus, the AIFS or RBO duration associated with the low-latency STA 422 may be shorter than the AIFS or RBO duration associated with the non-legacy STA 424, respectively. However, since the non-legacy STA 424 started its RBO countdown before the start of the restricted TWT SP, the non-legacy STA 424 may obtain a TXOP before the low-latency STA 422 completes its second RBO countdown. As a result, the low-latency STA 422 senses that the wireless medium is busy at time t5 and refrains from accessing the shared wireless medium for the duration of the TXOP of the non-legacy STA 424. After the TXOP ends, at time t6, the low-latency STA 422 may once again attempt to access the wireless medium.

[0051]

[0071] 4B and 4C show that under various conditions, non-member STAs may obtain a TXOP during a restricted TWT SP before low-latency STAs that are members of the restricted TWT SP. Although the low-latency STAs may access the wireless medium upon completion of the non-member STAs' TXOP, such delays in medium access may significantly increase the latency of data traffic associated with the low-latency STAs 412. Thus, existing rules regarding restricted TWT operation may not provide adequate protection for latency-sensitive traffic. Aspects of the present disclosure may provide greater protection for latency-sensitive traffic by preventing non-member STAs from accessing the shared wireless medium for at least a threshold duration following the start of a restricted TWT SP. In some aspects, all non-member STAs may follow one or more rules requiring such STAs to postpone access to the shared wireless medium for at least a threshold duration at the start of each restricted TWT SP. In some other aspects, the AP may transmit one or more frames that cause all non-member STAs to postpone access to the shared wireless medium for at least a threshold duration at the start of a restricted TWT SP.

[0052]

[0072] 5 shows a timing diagram 500 illustrating an example of wireless communication between devices belonging to a BSS. In the example of FIG. 5, the BSS is shown to include low latency STAs 502 and 504 and non-legacy STAs 506. The low latency STAs 502 and 504 communicate with each other from time t0 to t 105, while non-legacy STA 506 is not a member of the restricted TWT SP. In some implementations, each of STAs 502-506 may be an example of any of STAs 120a-120i of FIG. 1 or STA 200 of FIG. 2. Although only two low latency STAs and one non-legacy STA are shown in the example of FIG. 5, in an actual implementation, the BSS may include any number of low latency STAs and any number of non-legacy STAs.

[0053]

[0073] A first low-latency STA 502 attempts to access the shared wireless medium at the beginning of a restricted TWT SP. More specifically, the first low-latency STA 502 senses the medium is idle for an AIFS duration from time t0 to t2, and further counts down an RBO duration from time t2 to t4 before attempting to acquire a TXOP. In the example of FIG. 5, a second low-latency STA 504 also attempts to access the shared wireless medium at the beginning of a restricted TWT SP.

[0054]

[0074] In some implementations, to reduce the possibility of collisions between the low-latency STAs 502 and 504, the second low-latency STA 504 may wait a contention offset duration from time t0 to t1 before contending for medium access. As a result, the first low-latency STA 502 wins access to the wireless medium and obtains a TXOP from time t4 to t5. During the TXOP, the first low-latency STA 502 may transmit latency-sensitive traffic to or receive latency-sensitive traffic from the AP or another STA (such as in peer-to-peer communication). The second low-latency STA 504 senses that the medium is idle for the AIFS duration from time t1 to t3, and further counts down the RBO duration starting at time t3. However, the second low-latency STA 504 senses that the wireless medium is busy at time t4 and refrains from accessing the shared medium for the duration of the TXOP.

[0055]

[0075] In some implementations, all non-legacy STAs may be required to reset their RBO at the beginning of each restricted TWT SP. In other words, any non-member STAs that have data to transmit or receive during a restricted TWT SP must contend for medium access from the beginning of the restricted TWT SP. The non-legacy STAs 506 may attempt to access the shared wireless medium before the start of the restricted TWT SP (as described with reference to FIGS. 4A-4C). However, regardless of whether the non-legacy STAs 506 obtain a shortened TXOP or continue to count down the RBO, the non-legacy STAs 506 must contend for medium access again at the beginning of the restricted TWT SP.

[0056]

[0076] The non-legacy STA 506 senses the medium to be idle for the AIFS duration from time t0 to t3, and further counts down the RBO duration beginning at time t3. In some implementations, the data traffic associated with the non-legacy STA 506 may be assigned to a lower priority AC than the data traffic associated with the low-latency STAs 502 and 504. As a result, the non-legacy STA 506 loses medium access to the first low-latency STA 502. The non-legacy STA 506 senses the wireless medium to be busy at time t4, and refrains from accessing the shared medium for the duration of the TXOP.

[0057]

[0077] After the TXOP of the first low-latency STA 502 ends, at time t5, the second low-latency STA 504 and the non-legacy STA 506 may once again contend for access to the wireless medium. As shown in FIG. 5, the second low-latency STA 504 senses the medium to be idle for the AIFS duration from time t5 to t6, and counts down the RBO duration from time t6 to t8 before attempting to acquire the TXOP. The non-legacy STA 506 senses the medium to be idle for the AIFS duration from time t5 to t7, and counts down the RBO duration beginning at time t7.

[0058]

[0078] In some implementations, data traffic associated with the second low-latency STA 504 may be assigned to a higher priority AC than data traffic associated with the non-legacy STA 506. As a result, the second low-latency STA 504 wins access to the wireless medium and obtains a TXOP from time t8 to t9. The non-legacy STA 506 senses that the wireless medium is busy at time t8 and refrains from accessing the shared medium for the duration of the TXOP. After the TXOP of the second low-latency STA 504 ends, at time t9, the non-legacy STA 506 may once again contend for access to the wireless medium.

[0059]

[0079] In some implementations, membership in a restricted TWT SP may be limited such that each low-latency STA associated with the SP has a greater likelihood of winning a TXOP in a relatively short amount of time. For example, with reference to FIG. 5, if membership in a restricted TWT SP is limited to two, any additional low-latency STAs in the BSS may be assigned to a different restricted TWT SP.

[0060]

[0080] 5, it is assumed that data traffic associated with the non-legacy STA 506 is assigned to a lower priority AC than data traffic associated with the low-latency STAs 502 and 504. However, in some cases, data traffic associated with each of the STAs 502-506 may be assigned to the same AC. In such cases, the likelihood that either of the low-latency STAs 502 or 504 will win access to the wireless medium over the non-legacy STA 506 is significantly reduced. In some implementations, to further protect latency-sensitive traffic in the restricted TWT SP, non-member STAs may be prohibited from accessing the wireless medium during the restricted TWT SP.

[0061]

[0081] FIG. 6 shows a timing diagram 600 illustrating an example of wireless communication between devices belonging to a BSS. In the example of FIG. 6, the BSS is shown to include low-latency STAs 602 and 604 and a non-legacy STA 606. The low-latency STAs 602 and 604 are members of a restricted TWT SP (r-TWT SP) for a duration from time t0 to t8, while the non-legacy STA 606 is not a member of the restricted TWT SP. In some implementations, each of the STAs 602-606 may be an example of any of the STAs 120a-120i of FIG. 1 or the STA 200 of FIG. 2. Although only two low-latency STAs and one non-legacy STA are shown in the example of FIG. 6, in an actual implementation, the BSS may include any number of low-latency STAs and any number of non-legacy STAs.

[0062]

[0082] A first low-latency STA 602 attempts to access the shared wireless medium at the beginning of a restricted TWT SP. More specifically, the first low-latency STA 602 senses the medium is idle for an AIFS duration from time t0 to t2, and further counts down an RBO duration from time t2 to t4 before attempting to acquire a TXOP. In the example of FIG. 6, a second low-latency STA 604 also attempts to access the shared wireless medium at the beginning of a restricted TWT SP.

[0063]

[0083] In some implementations, to reduce the possibility of collisions between the low-latency STAs 602 and 604, the second low-latency STA 604 may wait a contention offset duration from time t0 to t1 before contending for medium access. As a result, the first low-latency STA 602 wins access to the wireless medium and obtains a TXOP from time t4 to t5. During the TXOP, the first low-latency STA 602 may transmit latency-sensitive traffic to or receive latency-sensitive traffic from the AP or another STA (such as in peer-to-peer communication). The second low-latency STA 604 senses that the medium is idle for the AIFS duration from time t1 to t3, and further counts down the RBO duration starting at time t3. However, the second low-latency STA 604 senses that the wireless medium is busy at time t4 and refrains from accessing the shared medium for the duration of the TXOP.

[0064]

[0084] In some implementations, all non-legacy STAs may be required to postpone access to the shared wireless medium for the duration of each restricted TWT SP. In other words, any non-member STAs that have data to transmit or receive during the restricted TWT SP must wait until the restricted TWT SP ends before contending for medium access. The non-legacy STAs 606 may attempt to access the wireless medium before the start of the restricted TWT SP (as described with reference to FIGS. 4A-4C). However, regardless of whether the non-legacy STAs 606 obtain a shortened TXOP or continue to count down the RBO, the non-legacy STAs 606 must postpone medium access for the duration of the restricted TWT SP from time t0 to t8.

[0065]

[0085] After the TXOP of the first low-latency STA 602 ends, at time t5, the second low-latency STA 604 may once again contend for access to the wireless medium. As shown in FIG. 6, the second low-latency STA 604 senses the medium idle for the AIFS duration from time t5 to t6, counts down the RBO duration from time t6 to t7, and obtains a TXOP from time t7 to t8. After the restricted TWT SP ends, at time t8, the non-legacy STA 606 may once again contend for access to the wireless medium. As shown in FIG. 6, the non-legacy STA 606 senses the medium idle for the AIFS duration from time t8 to t9, and further counts down the RBO duration starting at time t9.

[0066]

[0086] In some implementations, membership in a restricted TWT SP may be limited such that each low-latency STA associated with the SP has a greater likelihood of winning a TXOP in a relatively short amount of time. For example, with reference to FIG. 6, if membership in a restricted TWT SP is limited to two, any additional low-latency STAs in the BSS may be assigned to a different restricted TWT SP.

[0067]

[0087] Aspects of the present disclosure recognize that in some cases, low-latency STAs assigned to a restricted TWT SP may not utilize all (or any) of the SP to transmit or receive latency-sensitive traffic. In such cases, requiring non-member STAs to defer medium access for the duration of the restricted TWT SP may result in underutilization of the shared wireless medium. In some implementations, to improve medium utilization during the restricted TWT SP, non-member STAs may be required to defer medium access for only a portion of the restricted TWT SP.

[0068]

[0088] 7 shows a timing diagram 700 illustrating an example of wireless communication between devices belonging to a BSS. In the example of FIG. 7, the BSS is shown to include low latency STAs 702 and 704 and non-legacy STAs 706. The low latency STAs 702 and 704 communicate with each other from time t0 to t 11 7, the low-latency STAs 702-706 are members of a restricted TWT SP (r-TWT SP) for a duration up to 10 ms, while the non-legacy STAs 706 are not members of the restricted TWT SP. In some implementations, each of the STAs 702-706 may be an example of any of the STAs 120a-120i of FIG. 1 or the STA 200 of FIG. 2. Although only two low-latency STAs and one non-legacy STA are shown in the example of FIG. 7, in an actual implementation, the BSS may include any number of low-latency STAs and any number of non-legacy STAs.

[0069]

[0089] A first low-latency STA 702 attempts to access the shared wireless medium at the beginning of a restricted TWT SP. More specifically, the first low-latency STA 702 senses the medium is idle for an AIFS duration from time t0 to t2, and further counts down an RBO duration from time t2 to t4 before attempting to acquire a TXOP. In the example of FIG. 7, a second low-latency STA 704 also attempts to access the shared wireless medium at the beginning of a restricted TWT SP.

[0070]

[0090] In some implementations, to reduce the possibility of collisions between the low-latency STAs 702 and 704, the second low-latency STA 704 may wait a contention offset duration from time t0 to t1 before contending for medium access. As a result, the first low-latency STA 702 wins access to the wireless medium and obtains a TXOP from time t4 to t6. During the TXOP, the first low-latency STA 702 may transmit latency-sensitive traffic to or receive latency-sensitive traffic from the AP or another STA (such as in peer-to-peer communication). The second low-latency STA 704 senses that the medium is idle for the AIFS duration from time t1 to t3, and further counts down the RBO duration starting at time t3. However, the second low-latency STA 704 senses that the wireless medium is busy at time t4 and refrains from accessing the shared medium for the duration of the TXOP.

[0071]

[0091] In some implementations, all non-legacy STAs may be required to postpone access to the shared wireless medium for the quiet duration from the start of each restricted TWT SP. In other words, any non-member STAs that have data to transmit or receive during the restricted TWT SP must wait until the quiet duration expires before they can contend for medium access. In some implementations, the quiet duration may be signaled by the AP (not shown for simplicity). For example, the quiet duration may be indicated by a quiet element carried in a management frame (such as a beacon or probe response) transmitted by the AP. The non-legacy STAs 706 may attempt to access the wireless medium before the start of the restricted TWT SP (as described with reference to FIGS. 4A-4C). However, regardless of whether the non-legacy STAs 706 obtain a shortened TXOP or continue to count down the RBO, the non-legacy STAs 706 must postpone medium access for at least the quiet duration from time t0 to t5.

[0072]

[0092] The non-legacy STA 706 senses the wireless medium is busy for the remainder of the TXOP from time t5 to t6. After the TXOP of the first low-latency STA 702 ends, at time t6, the second low-latency STA 704 and the non-legacy STA 706 may once again contend for access to the wireless medium. As shown in FIG. 7, the second low-latency STA 704 senses the medium is idle for the AIFS duration from time t6 to t7, and counts down the RBO duration from time t7 to t9 before attempting to acquire the TXOP. The non-legacy STA 706 senses the medium is idle for the AIFS duration from time t6 to t8, and counts down the RBO duration beginning at time t8.

[0073]

[0093] In some implementations, the data traffic associated with the second low latency STA 704 may be assigned to a higher priority AC than the data traffic associated with the non-legacy STA 706. As a result, the second low latency STA 704 wins access to the wireless medium and is assigned a higher priority AC than the data traffic associated with the non-legacy STA 706 from time t9 to t 10 The non-legacy STA 706 senses that the wireless medium is busy at time t9 and refrains from accessing the shared medium for the duration of the TXOP. After the TXOP of the second low latency STA 704 ends, at time t 10 In, the non-legacy STAs 706 may once again contend for access to the wireless medium.

[0074]

[0094] In some implementations, membership in a restricted TWT SP may be limited such that each low-latency STA associated with the SP has a greater likelihood of winning a TXOP in a relatively short amount of time. For example, with reference to FIG. 7, if membership in a restricted TWT SP is limited to two, any additional low-latency STAs in the BSS may be assigned to a different restricted TWT SP.

[0075]

[0095] In some implementations, the quiet duration may be selected to balance the efficiency of medium utilization and the latency gain for latency-sensitive traffic. In the example of FIG. 7, the quiet duration is configured to end before the end of a single TXOP. However, in some other implementations, the quiet duration may be configured to span one or more TXOPs.

[0076]

[0096] The implementations described with reference to Figures 5-7 rely on non-member STAs following updated rules regarding restricted TWT operation. For example, such updates to the rules may be implemented through future revisions to the IEEE 802.11 standard. However, aspects of the present disclosure recognize that non-legacy STAs that comply with existing versions of the IEEE 802.11 standard may not follow the updated rules. Thus, in some other implementations, non-member STAs may be explicitly signaled to defer medium access using existing wireless communication protocols. In such implementations, the AP may capture the wireless medium when the TWT SP begins and transmit one or more packets that cause non-member STAs to defer medium access for at least a threshold interval while allowing low latency STAs to access the wireless medium during such interval.

[0077]

[0097] FIG. 8A illustrates a timing diagram 800 showing an example of wireless communication between devices belonging to a BSS. In the example of FIG. 8A, the BSS is shown to include an AP 802, a low-latency STA 804, and a non-legacy STA 806. The low-latency STA 804 is a member of a restricted TWT SP (r-TWT SP) for a duration from time t1 to t9, while the non-legacy STA 806 is not a member of the restricted TWT SP. In some implementations, the AP 802 may be an example of the AP 110 of FIG. 1 or the AP 300 of FIG. 3. In some implementations, each of the STAs 804 and 806 may be an example of any of the STAs 120a-120i of FIG. 1 or the STA 200 of FIG. 2. Although only one low-latency STA and one non-legacy STA are shown in the example of FIG. 8A, in an actual implementation, the BSS may include any number of low-latency STAs and any number of non-legacy STAs.

[0078]

[0098] In some implementations, the AP 802 may transmit a clear-to-send (CTS)-to-self frame over the shared wireless medium when the restricted TWT SP begins. More specifically, the AP 802 attempts to time the transmission of the CTS frame to self to coincide with the start of the restricted TWT SP. In the example of FIG. 8A, the non-legacy STA 806 is counting down its RBO duration before the start of the restricted TWT SP. The AP 802 senses the medium is idle for a point coordination function (PCF) interframe space (PIFS) duration from time t0 to t1, and proceeds to transmit a CTS frame to self at time t1. The low-latency STA 804 also attempts to access the shared wireless medium at the start of the restricted TWT SP. However, the low-latency STA 804 senses the medium is busy from time t1 to t2 during the transmission of the CTS frame to self.

[0079]

[0099] In some implementations, the duration field (in the MAC header) of the CTS-to-self frame may be used to protect latency-sensitive traffic in the restricted TWT SP. More specifically, the value of the duration field indicates the duration for which the wireless medium should be reserved. STAs that comply with existing versions of the IEEE 802.11 standard must postpone medium access for at least the duration indicated by the duration field. In some implementations, to protect latency-sensitive traffic in the restricted TWT SP, the duration indicated by the duration field may be greater than the duration required to transmit the trigger frame. As shown in FIG. 8A, the non-legacy STA 806 sets its network allocation vector (NAV) to the duration indicated by the duration field of the CTS-to-self frame, spanning the duration from time t2 to t5.

[0080]

[0100] In some implementations, the low-latency STAs 804 may be configured to ignore any CTS-to-self frame transmitted by the AP at the start of a limited TWT SP. Thus, the low-latency STAs 804 do not set their NAV according to the duration field of the CTS-to-self frame. Instead, the low-latency STAs 804 may start contending for medium access immediately after transmitting the CTS-to-self frame. As shown in FIG. 8A, the low-latency STAs 804 sense the medium is idle during the AIFS duration from time t2 to t3, count down the RBO duration from time t3 to t4, and obtain a TXOP from time t4 to t6. During the TXOP, the low-latency STAs 804 may transmit latency-sensitive traffic to or receive latency-sensitive traffic from the AP or another STA (such as in peer-to-peer communication).

[0081]

[0101] At the end of the NAV duration, at time t5, the non-legacy STA 806 may contend for medium access. However, the non-legacy STA 806 senses that the medium is busy at time t5 due to the TXOP of the low-latency STA 804. Thus, the non-legacy STA 806 refrains from accessing the shared medium for the duration of the TXOP. After the TXOP of the low-latency STA 804 ends, at time t6, the non-legacy STA 806 may contend for medium access once again. As shown in FIG. 8A, the non-legacy STA 806 senses that the medium is idle during the AIFS duration from time t6 to t7, counts down the RBO duration from time t7 to t8, and obtains the TXOP from time t8 to t9.

[0082]

[0102] In some implementations, multiple low latency STAs may be members of a restricted TWT SP. In such implementations, the non-legacy STAs 806 may postpone their medium access for longer (as described with reference to FIGS. 5-7). For example, data traffic associated with low latency STAs may be assigned to a higher priority AC than data traffic associated with non-member STAs, so that the low latency STAs are more likely to win medium access than the non-member STAs during a given contention period.

[0083]

[0103] In some implementations, membership in a restricted TWT SP may be limited such that each low-latency STA associated with the SP has a greater likelihood of winning a TXOP in a relatively short amount of time. For example, with reference to FIG. 8A, if membership in a restricted TWT SP is limited to two, any additional low-latency STAs in the BSS may be assigned to a different restricted TWT SP.

[0084]

[0104] In some implementations, the duration indicated by the duration field of the CTS-to-self frame (also referred to herein as the "NAV duration") may be selected to balance efficiency of medium utilization and latency gain for latency-sensitive traffic. In the example of FIG. 8A, the NAV duration is configured to end before the end of a single TXOP. However, in some other implementations, the NAV duration may be configured to span one or more TXOPs.

[0085]

[0105] FIG. 8B illustrates a timing diagram 810 showing an example of wireless communication between devices belonging to a BSS. In the example of FIG. 8B, the BSS is shown to include an AP 812, a low-latency STA 814, and a non-legacy STA 816. The low-latency STA 814 is a member of a restricted TWT SP (r-TWT SP) for a duration from time t0 to t9, while the non-legacy STA 816 is not a member of the restricted TWT SP. In some implementations, the AP 812 may be an example of the AP 110 of FIG. 1 or the AP 300 of FIG. 3. In some implementations, each of the STAs 814 and 816 may be an example of any of the STAs 120a-120i of FIG. 1 or the STA 200 of FIG. 2. Although only one low-latency STA and one non-legacy STA are shown in the example of FIG. 8B, in an actual implementation, the BSS may include any number of low-latency STAs and any number of non-legacy STAs.

[0086]

[0106] In some implementations, the AP 812 may transmit a clear to send (CTS) frame to itself over the shared wireless medium when the restricted TWT SP begins. More specifically, the AP 812 attempts to time the transmission of the CTS frame to itself to coincide with the start of the restricted TWT SP. In the example of FIG. 8B, the non-legacy STA 816 obtains a shortened TXOP before the start of the restricted TWT SP. The AP 812 senses that the medium is idle for a PIFS duration from time t0 to t1, and proceeds to transmit a CTS frame to itself at time t1. The low-latency STA 814 also attempts to access the shared wireless medium at the start of the restricted TWT SP. However, because the PIFS duration is shorter than any AIFS duration, the AP 812 wins medium access over the low-latency STA 814. Thus, the low-latency STA 814 senses that the medium is busy from time t1 to t2 during the transmission of the CTS frame to itself.

[0087]

[0107] In some implementations, the duration field (in the MAC header) of the CTS-to-self frame may be used to protect latency-sensitive traffic in the restricted TWT SP. As described with reference to FIG. 8A, STAs that comply with existing versions of the IEEE 802.11 standard must postpone medium access for at least the duration indicated by the duration field. In some implementations, to protect latency-sensitive traffic in the restricted TWT SP, the duration indicated by the duration field may be greater than the duration required to transmit the trigger frame. As shown in FIG. 8B, the non-legacy STA 816 sets its NAV to the duration indicated by the duration field of the CTS-to-self frame, spanning the duration from time t2 to t5.

[0088]

[0108] In some implementations, the low-latency STAs 814 may be configured to ignore any CTS-to-self frame transmitted by the AP at the start of a limited TWT SP. Thus, the low-latency STAs 814 do not set their NAV according to the duration field of the CTS-to-self frame. Instead, the low-latency STAs 814 may begin to contend for the wireless medium immediately after transmitting the CTS-to-self frame. As shown in FIG. 8B, the low-latency STAs 814 sense the medium is idle during the AIFS duration from time t2 to t3, count down the RBO duration from time t3 to t4, and obtain a TXOP from time t4 to t6. During the TXOP, the low-latency STAs 814 may transmit latency-sensitive traffic to or receive latency-sensitive traffic from the AP or another STA (such as in peer-to-peer communication).

[0089]

[0109] At the end of the NAV duration, at time t5, the non-legacy STA 816 may contend for medium access. However, the non-legacy STA 816 senses that the medium is busy at time t5 due to the TXOP of the low-latency STA 814. Thus, the non-legacy STA 816 refrains from accessing the shared medium for the duration of the TXOP. After the TXOP of the low-latency STA 814 ends, at time t6, the non-legacy STA 816 may contend for medium access once again. As shown in FIG. 8B, the non-legacy STA 816 senses that the medium is idle during the AIFS duration from time t6 to t7, counts down the RBO duration from time t7 to t8, and obtains the TXOP from time t8 to t9.

[0090]

[0110] In some implementations, multiple low-latency STAs (not shown for simplicity) may be members of the restricted TWT SP. In such implementations, the non-legacy STAs 816 may postpone their medium access for longer (as described with reference to FIGS. 5-7). For example, data traffic associated with low-latency STAs may be assigned to a higher priority AC than data traffic associated with non-member STAs, so that the low-latency STAs are more likely to win medium access than the non-member STAs during a given contention period.

[0091]

[0111] In some implementations, membership in a restricted TWT SP may be limited such that each low-latency STA associated with the SP has a greater likelihood of winning a TXOP in a relatively short amount of time. For example, with reference to FIG. 8B, if membership in a restricted TWT SP is limited to two, any additional low-latency STAs in the BSS may be assigned to a different restricted TWT SP.

[0092]

[0112] In some implementations, the NAV duration indicated by the duration field of the CTS-to-self frame may be selected to balance the efficiency of medium utilization and the latency gain for latency-sensitive traffic. In the example of FIG. 8B, the NAV duration is configured to end before the end of a single TXOP. However, in some other implementations, the NAV duration may be configured to span one or more TXOPs.

[0093]

[0113] FIG. 9A illustrates a timing diagram 900 showing an example of wireless communication between devices belonging to a BSS. In the example of FIG. 9A, the BSS is shown to include an AP 902, a low-latency STA 904, and a non-legacy STA 906. The low-latency STA 904 is a member of a restricted TWT SP (r-TWT SP) for a duration from time t1 to t8, while the non-legacy STA 906 is not a member of the restricted TWT SP. In some implementations, the AP 902 may be an example of the AP 110 of FIG. 1 or the AP 300 of FIG. 3. In some implementations, each of the STAs 904 and 906 may be an example of any of the STAs 120a-120i of FIG. 1 or the STA 200 of FIG. 2. Although only one low-latency STA and one non-legacy STA are shown in the example of FIG. 9A, in an actual implementation, the BSS may include any number of low-latency STAs and any number of non-legacy STAs.

[0094]

[0114] In some implementations, the AP 902 may transmit a trigger frame over the shared wireless medium when the restricted TWT SP begins. More specifically, the AP 902 attempts to time the transmission of the trigger frame to coincide with the start of the restricted TWT SP. In the example of FIG. 9A, the non-legacy STA 906 is counting down its RBO duration before the start of the restricted TWT SP. The AP 902 senses that the medium is idle for a PIFS duration from time t0 to t1 and proceeds to transmit a trigger frame at time t1. In some implementations, the trigger frame may solicit a trigger-based (TB) physical layer convergence protocol (PLCP) protocol data unit (PPDU) from one or more low-latency STAs (such as the low-latency STA 904). As shown in FIG. 9A, the low latency STA 904 responds to the trigger frame by transmitting uplink (UL) data in a TB PPDU to the AP 902 at time t3.

[0095]

[0115] In some implementations, the duration field (in the MAC header) of the trigger frame may be used to protect latency-sensitive traffic in the restricted TWT SP. As described with reference to FIG. 8A, STAs that comply with existing versions of the IEEE 802.11 standard must postpone medium access for at least the duration indicated by the duration field. In some implementations, the duration indicated by the duration field may be greater than the duration required to transmit the trigger frame. As shown in FIG. 9A, the non-legacy STA 906 sets its NAV to the duration indicated by the duration field of the trigger frame, spanning the duration from time t2 to t4.

[0096]

[0116] At the end of the NAV duration, at time t4, the non-legacy STA 906 may contend for medium access. However, the non-legacy STA 906 senses that the medium is busy at time t4 due to the transmission of the TB PPDU. Thus, the non-legacy STA 906 refrains from accessing the shared medium for the duration of the TB PPDU. After the transmission of the TB PPDU is completed, at time t5, the non-legacy STA 906 may contend for medium access once again. As shown in FIG. 9A, the non-legacy STA 906 senses that the medium is idle during the AIFS duration from time t5 to t6, counts down the RBO duration from time t6 to t7, and acquires a TXOP from time t7 to t8.

[0097]

[0117] In some implementations, the trigger frame may be used to solicit TB PPDUs from multiple low-latency STAs (not shown for simplicity). In such implementations, multiple low-latency STAs may transmit their respective UL data to the AP 902 simultaneously in a TB PPDU (from time t3 to t5). In some implementations, the AP 902 may poll the low-latency STAs prior to the start of the restricted TWT SP to determine which (if any) of the STAs have UL data to send. For example, the AP 902 may transmit a buffer status report poll (BSRP) trigger frame to the low-latency STAs associated with the restricted TWT SP. Each low-latency STA responds to the BSRP trigger frame by sending a buffer status report (BSR) back to the AP 902 indicating the amount of UL data buffered by the STA. The AP 902 may use the information carried in each BSR to determine resource allocation for the TB PPDU.

[0098]

[0118] In some implementations, the NAV duration carried in the trigger frame may be selected to balance the efficiency of medium utilization and the latency gain for latency-sensitive traffic. In the example of FIG. 9A, the NAV duration is configured to end before the end of the TB PPDU. However, in some other implementations, the NAV duration may be configured to extend beyond the duration of the TB PPDU.

[0099]

[0119] FIG. 9B illustrates a timing diagram 910 showing an example of wireless communication between devices belonging to a BSS. In the example of FIG. 9B, the BSS is shown to include an AP 912, a low-latency STA 914, and a non-legacy STA 916. The low-latency STA 914 is a member of a restricted TWT SP (r-TWT SP) for a duration from time t0 to t8, while the non-legacy STA 916 is not a member of the restricted TWT SP. In some implementations, the AP 912 may be an example of the AP 110 of FIG. 1 or the AP 300 of FIG. 3. In some implementations, each of the STAs 914 and 916 may be an example of any of the STAs 120a-120i of FIG. 1 or the STA 200 of FIG. 2. Although only one low-latency STA and one non-legacy STA are shown in the example of FIG. 9B, in an actual implementation, the BSS may include any number of low-latency STAs and any number of non-legacy STAs.

[0100]

[0120] In some implementations, the AP 912 may transmit a trigger frame over the shared wireless medium when the restricted TWT SP begins. More specifically, the AP 912 attempts to time the transmission of the trigger frame to coincide with the start of the restricted TWT SP. In the example of FIG. 9B, the non-legacy STA 916 obtains a shortened TXOP before the start of the restricted TWT SP. The AP 912 senses that the medium is idle for a PIFS duration from time t0 to t1 and proceeds to transmit a trigger frame at time t1. The trigger frame solicits a TB PPDU from one or more low-latency STAs (such as the low-latency STA 914). As shown in FIG. 9B, the low-latency STA 914 responds to the trigger frame by transmitting UL data in a TB PPDU to the AP 912 at time t3.

[0101]

[0121] In some implementations, the duration field (in the MAC header) of the trigger frame may be used to protect latency-sensitive traffic in a restricted TWT SP. As described with reference to FIG. 8A, STAs that comply with existing versions of the IEEE 802.11 standard must postpone medium access for at least the duration indicated by the duration field. Thus, to protect latency-sensitive traffic, the duration indicated by the duration field may be greater than the duration required to transmit the trigger frame. As shown in FIG. 9B, the non-legacy STA 916 sets its NAV to the duration indicated by the duration field of the trigger frame, spanning the duration from time t2 to t4.

[0102]

[0122] At the end of the NAV duration, at time t4, the non-legacy STA 916 may contend for medium access. However, the non-legacy STA 916 senses that the medium is busy at time t4 due to the transmission of the TB PPDU. Thus, the non-legacy STA 916 refrains from accessing the shared medium for the duration of the TB PPDU. After the transmission of the TB PPDU is completed, the non-legacy STA 916 may contend for medium access again at time t5. As shown in FIG. 9B, the non-legacy STA 916 senses that the medium is idle for the AIFS duration from time t5 to t6, counts down the RBO duration from time t6 to t7, and acquires a TXOP from time t7 to t8.

[0103]

[0123] In some implementations, the trigger frame may be used to solicit TB PPDUs from multiple low-latency STAs (not shown for simplicity). In such implementations, multiple low-latency STAs may transmit their respective UL data to the AP 912 simultaneously in a TB PPDU (from time t3 to t5). In some implementations, the AP 912 may poll the low-latency STAs prior to the start of the restricted TWT SP to determine which (if any) of the STAs have UL data to send. For example, the AP 912 may transmit a BSRP trigger frame to the low-latency STAs associated with the restricted TWT SP. Each low-latency STA responds to the BSRP trigger frame by sending back a BSR to the AP 912 indicating the amount of UL data buffered by the STA. The AP 912 may use the information carried in each BSR to determine resource allocation for the TB PPDU.

[0104]

[0124] In some implementations, the NAV duration carried in the trigger frame may be selected to balance efficiency of medium utilization and latency gain for latency-sensitive traffic. In the example of FIG. 9B, the NAV duration is configured to end before the end of the TB PPDU. However, in some other implementations, the NAV duration may be configured to extend beyond the duration of the TB PPDU.

[0105]

[0125] 10A shows a timing diagram 1000 illustrating an example of wireless communication between devices belonging to a BSS. In the example of FIG. 10A, the BSS is shown to include an AP 1002, a low-latency STA 1004, and a non-legacy STA 1006. The low-latency STA 1004 receives a 10-second hop count from time t1 to time t2. 1110A , while the non-legacy STA 1006 is not a member of the restricted TWT SP. In some implementations, the AP 1002 may be an example of the AP 110 of FIG. 1 or the AP 300 of FIG. 3. In some implementations, each of the STAs 1004 and 1006 may be an example of any of the STAs 120a-120i of FIG. 1 or the STA 200 of FIG. 2. Although only one low-latency STA and one non-legacy STA are shown in the example of FIG. 10A , in an actual implementation, the BSS may include any number of low-latency STAs and any number of non-legacy STAs.

[0106]

[0126] In some implementations, the AP 1002 may transmit a multi-user (MU) request-to-send (RTS) frame over the shared wireless medium when the restricted TWT SP begins. More specifically, the AP 1002 attempts to time the transmission of the MU-RTS frame to coincide with the start of the restricted TWT SP. In the example of FIG. 10A, the non-legacy STA 1006 is counting down its RBO duration before the start of the restricted TWT SP. Thus, the AP 1002 senses that the medium is idle for a PIFS duration from time t0 to t1 and proceeds to transmit the MU-RTS frame at time t1. In some implementations, the MU-RTS frame may identify one or more low-latency STAs (such as the low-latency STA 1004). As shown in FIG. 10A, the low-latency STA 1004 responds to the MU-RTS by sending a CTS back to the AP 1002 at time t3.

[0107]

[0127] In some implementations, the duration field (in the MAC header) of the MU-RTS frame may be used to protect latency-sensitive traffic in the restricted TWT SP. As described with reference to FIG. 8A, STAs that comply with existing versions of the IEEE 802.11 standard must postpone medium access for at least the duration indicated by the duration field. In some implementations, the duration indicated by the duration field may be greater than the duration required to transmit the MU-RTS frame. As shown in FIG. 10A, the non-legacy STA 1006 sets its NAV to the duration indicated by the duration field of the MU-RTS frame, which spans the duration from time t2 to t7. In some other implementations, the non-legacy STA 1006 may set its NAV to the duration indicated by the duration field of the CTS frame.

[0108]

[0128] In some implementations, the low-latency STAs 1004 may be configured to ignore the duration field of the MU-RTS frame transmitted by the AP at the start of the restricted TWT SP. Thus, the low-latency STAs 1004 do not set their NAV according to the duration field of the MU-RTS frame. Instead, the low-latency STAs 1004 may start contending for medium access immediately after the transmission of the CTS. As shown in FIG. 10A, the low-latency STAs 1004 sense that the medium is idle during the AIFS duration from time t4 to t5, count down the RBO duration from time t5 to t6, and obtain a TXOP from time t6 to t8. During the TXOP, the low-latency STAs 1004 may transmit latency-sensitive traffic to or receive latency-sensitive traffic from the AP or another STA (such as in peer-to-peer communication).

[0109]

[0129] At the end of the NAV duration, at time t7, the non-legacy STA 1006 may contend for medium access. However, the non-legacy STA 1006 senses that the medium is busy at time t7 due to the TXOP of the low-latency STA 1004. Thus, the non-legacy STA 1006 refrains from accessing the shared medium for the duration of the TXOP. After the TXOP of the low-latency STA 1004 ends, at time t8, the non-legacy STA 1006 may once again contend for medium access. As shown in FIG. 10A, the non-legacy STA 1006 senses that the medium is idle for the AIFS duration from time t8 to t9, and the non-legacy STA 1006 may once again contend for medium access from time t9 to t10. 10 Count down the RBO duration until time t 10 From 11 Get TXOP until

[0110]

[0130] In some implementations, the MU-RTS may identify multiple low-latency STAs (not shown for simplicity). In such implementations, each low-latency STA may transmit a respective CTS frame from time t3 to t4 in response to the MU-RTS frame. As a result, the non-legacy STAs 1006 may postpone their medium access for longer (as described with reference to Figures 5-7). For example, data traffic associated with low-latency STAs may be assigned to a higher priority AC than data traffic associated with non-member STAs, so that the low-latency STAs are more likely to win medium access than the non-member STAs during a given contention period.

[0111]

[0131] In some implementations, membership in a restricted TWT SP may be limited such that each low-latency STA associated with the SP has a greater likelihood of winning a TXOP in a relatively short amount of time. For example, with reference to FIG. 10A, if membership in a restricted TWT SP is limited to two, any additional low-latency STAs in the BSS may be assigned to a different restricted TWT SP.

[0112]

[0132] In some implementations, the NAV duration indicated by the duration field of the CTS-to-self frame may be selected to balance the efficiency of medium utilization and the latency gain for latency-sensitive traffic. In the example of FIG. 10A, the NAV duration is configured to end before the end of a single TXOP. However, in some other implementations, the NAV duration may be configured to span one or more TXOPs.

[0113]

[0133] 10B shows a timing diagram 1010 illustrating an example of wireless communication between devices belonging to a BSS. In the example of FIG. 10B, the BSS is shown to include an AP 1012, a low-latency STA 1014, and a non-legacy STA 1016. The low-latency STA 1014 receives a low-latency STA 1016 from time t0 to t 11 10B, while the non-legacy STA 1016 is not a member of the restricted TWT SP. In some implementations, the AP 1012 may be an example of the AP 110 of FIG. 1 or the AP 300 of FIG. 3. In some implementations, each of the STAs 1014 and 1016 may be an example of any of the STAs 120a-120i of FIG. 1 or the STA 200 of FIG. 2. Although only one low latency STA and one non-legacy STA are shown in the example of FIG. 10B, in an actual implementation, the BSS may include any number of low latency STAs and any number of non-legacy STAs.

[0114]

[0134] In some implementations, the AP 1012 may transmit a MU-RTS frame over the shared wireless medium when the restricted TWT SP begins. More specifically, the AP 1012 attempts to time the transmission of the MU-RTS frame to coincide with the start of the restricted TWT SP. In the example of FIG. 10B, the non-legacy STA 1016 obtains a shortened TXOP before the start of the restricted TWT SP. The AP 1012 senses that the medium is idle for a PIFS duration from time t0 to t1 and proceeds to transmit the MU-RTS frame at time t1. In some implementations, the MU-RTS frame may identify one or more low-latency STAs (such as the low-latency STA 1014). As shown in FIG. 10B, the low-latency STA 1014 responds to the MU-RTS by sending a CTS back to the AP 1012 at time t3.

[0115]

[0135] In some implementations, the duration field (in the MAC header) of the MU-RTS frame may be used to protect latency-sensitive traffic in restricted TWT SPs. As described with reference to FIG. 8A, STAs that comply with existing versions of the IEEE 802.11 standard must postpone medium access for at least the duration indicated by the duration field. In some implementations, the duration indicated by the duration field may be greater than the duration required to transmit the MU-RTS frame. As shown in FIG. 10B, the non-legacy STA 1016 sets its NAV to the duration indicated by the duration field of the MU-RTS frame, which spans the duration from time t2 to t7. In some other implementations, the non-legacy STA 1016 may set its NAV to the duration indicated by the duration field of the CTS frame.

[0116]

[0136] In some implementations, the low-latency STAs may be configured to ignore the duration field of the MU-RTS frame transmitted by the AP at the start of the restricted TWT SP. Thus, the low-latency STAs 1014 do not set their NAV according to the duration field of the MU-RTS frame. Instead, the low-latency STAs 1014 may start contending for medium access immediately after the transmission of the CTS. As shown in FIG. 10B, the low-latency STAs 1014 sense that the medium is idle during the AIFS duration from time t4 to t5, count down the RBO duration from time t5 to t6, and obtain a TXOP from time t6 to t8. During the TXOP, the low-latency STAs 1014 may transmit latency-sensitive traffic to or receive latency-sensitive traffic from the AP or another STA (such as in peer-to-peer communication).

[0117]

[0137] At the end of the NAV duration, at time t7, the non-legacy STA 1016 may contend for medium access. However, the non-legacy STA 1016 senses that the medium is busy at time t7 due to the TXOP of the low-latency STA 1014. Thus, the non-legacy STA 1016 refrains from accessing the shared medium for the duration of the TXOP. After the TXOP of the low-latency STA 1014 ends, at time t8, the non-legacy STA 1016 may once again contend for medium access. As shown in FIG. 10B, the non-legacy STA 1016 senses that the medium is idle for the AIFS duration from time t8 to t9, and the non-legacy STA 1016 refrains from accessing the shared medium for the duration of the TXOP. 10 Count down the RBO duration until time t 10 From 11 Get TXOP until

[0118]

[0138] In some implementations, the MU-RTS may identify multiple low-latency STAs (not shown for simplicity). In such implementations, each low-latency STA may transmit a respective CTS frame from time t3 to t4 in response to the MU-RTS frame. As a result, the non-legacy STAs 1016 may postpone their medium access for longer (as described with reference to Figures 5-7). For example, data traffic associated with low-latency STAs may be assigned to a higher priority AC than data traffic associated with non-member STAs, so that the low-latency STAs are more likely to win medium access than the non-member STAs during a given contention period.

[0119]

[0139] In some implementations, membership in a restricted TWT SP may be limited such that each low-latency STA associated with the SP has a greater likelihood of winning a TXOP in a relatively short amount of time. For example, with reference to FIG. 10B, if membership in a restricted TWT SP is limited to two, any additional low-latency STAs in the BSS may be assigned to a different restricted TWT SP.

[0120]

[0140] In some implementations, the NAV duration indicated by the duration field of the CTS-to-self frame may be selected to balance the efficiency of medium utilization and the latency gain for latency-sensitive traffic. In the example of FIG. 10B, the NAV duration is configured to end before the end of a single TXOP. However, in some other implementations, the NAV duration may be configured to span one or more TXOPs.

[0121]

[0141] 11A shows a timing diagram 1100 illustrating an example of wireless communication between devices belonging to a BSS. In the example of FIG. 11A, the BSS is shown to include an AP 1102, a low-latency STA 1104, and a non-legacy STA 1106. The low-latency STA 1104 receives a 1-hop hop count from time t1 to time t2. 1211A , while the non-legacy STA 1106 is not a member of the restricted TWT SP. In some implementations, the AP 1102 may be an example of the AP 110 of FIG. 1 or the AP 300 of FIG. 3. In some implementations, each of the STAs 1104 and 1106 may be an example of any of the STAs 120a-120i of FIG. 1 or the STA 200 of FIG. 2. Although only one low-latency STA and one non-legacy STA are shown in the example of FIG. 11A , in an actual implementation, the BSS may include any number of low-latency STAs and any number of non-legacy STAs.

[0122]

[0142] In some implementations, the AP 1102 may transmit a MU-RTS frame over the shared wireless medium when the restricted TWT SP begins. More specifically, the AP 1102 attempts to time the transmission of the MU-RTS frame to coincide with the start of the restricted TWT SP. In the example of FIG. 11A, the non-legacy STA 1106 is counting down its RBO duration before the start of the restricted TWT SP. Thus, the AP 1102 senses that the medium is idle for the PIFS duration from time t0 to t1 and proceeds to transmit the MU-RTS frame at time t1. In some implementations, the MU-RTS frame may identify one or more low-latency STAs (such as the low-latency STA 1104). As shown in FIG. 11A, the low-latency STA 1104 responds to the MU-RTS by sending a CTS back to the AP 1102 at time t3.

[0123]

[0143] In some implementations, the duration field (in the MAC header) of the MU-RTS frame may be used to protect latency-sensitive traffic in restricted TWT SPs. As described with reference to FIG. 8A, STAs that comply with existing versions of the IEEE 802.11 standard must postpone medium access for at least the duration indicated by the duration field. In some implementations, the duration indicated by the duration field may be greater than the duration required to transmit the MU-RTS frame. As shown in FIG. 11A, the non-legacy STA 1106 sets its NAV to the duration indicated by the duration field of the MU-RTS frame, which spans the duration from time t2 to t8. In some other implementations, the non-legacy STA 1106 may set its NAV to the duration indicated by the duration field of the CTS frame.

[0124]

[0144] In some implementations, the AP 1102 may transmit a trigger frame at time t5 following receipt of the CTS frame. In some implementations, the trigger frame may solicit a TB PPDU from one or more low-latency STAs (such as the low-latency STA 1104). As shown in FIG. 11A, the low-latency STA 904 responds to the trigger frame by transmitting UL data in a TB PPDU to the AP 1102 at time t7.

[0125]

[0145] At the end of the NAV duration, at time t8, the non-legacy STA 1106 may contend for medium access. However, the non-legacy STA 1106 senses that the medium is busy at time t8 due to the transmission of the TB PPDU. Thus, the non-legacy STA 1106 refrains from accessing the shared medium for the duration of the TB PPDU. After the transmission of the TB PPDU is completed, at time t9, the non-legacy STA 1106 may contend once again for medium access. As shown in FIG. 11A, the non-legacy STA 1106 may contend for medium access from time t9 to t 10The medium is sensed as being idle for the AIFS duration up to time t 10 From 11 Count down the RBO duration until time t 11 From 12 Get TXOP until

[0126]

[0146] In some implementations, the MU-RTS may identify multiple low-latency STAs (not shown for simplicity). In such implementations, each low-latency STA may transmit a respective CTS frame from time t3 to t4 in response to the MU-RTS frame. In some implementations, the trigger frame may be used to solicit TB PPDUs from multiple low-latency STAs (not shown for simplicity). In such implementations, multiple low-latency STAs may transmit their respective UL data to the AP 1102 simultaneously in a TB PPDU (from time t7 to t9).

[0127]

[0147] In some implementations, the AP 1102 may poll the low-latency STAs prior to the start of the restricted TWT SP to determine which (if any) of the STAs have UL data to send. For example, the AP 1102 may send a BSRP trigger frame to the low-latency STAs associated with the restricted TWT SP. Each low-latency STA responds to the BSRP trigger frame by sending back a BSR to the AP 1102 indicating the amount of UL data buffered by the STA. The AP 1102 may use the information carried in each BSR to determine resource allocation for the TB PPDU.

[0128]

[0148] In some implementations, the NAV duration indicated by the duration field of the MU-RTS frame may be selected to balance efficiency of medium utilization and latency gain for latency-sensitive traffic. In the example of FIG. 11A, the NAV duration is configured to end before the end of the TB PPDU. However, in some other implementations, the NAV duration may be configured to extend beyond the duration of the TB PPDU.

[0129]

[0149] 11B shows a timing diagram 1110 illustrating an example of wireless communication between devices belonging to a BSS. In the example of FIG. 11B, the BSS is shown to include an AP 1112, a low-latency STA 1114, and a non-legacy STA 1116. The low-latency STA 1114 receives a low-latency STA 1116 from time t0 to t 12 11B, while the non-legacy STAs 1116 are not members of the restricted TWT SP. In some implementations, the AP 1112 may be an example of the AP 110 of FIG. 1 or the AP 300 of FIG. 3. In some implementations, each of the STAs 1114 and 1116 may be an example of any of the STAs 120a-120i of FIG. 1 or the STA 200 of FIG. 2. Although only one low-latency STA and one non-legacy STA are shown in the example of FIG. 11B, in an actual implementation, the BSS may include any number of low-latency STAs and any number of non-legacy STAs.

[0130]

[0150] In some implementations, the AP 1112 may transmit a MU-RTS frame over the shared wireless medium when the restricted TWT SP begins. More specifically, the AP 1112 attempts to time the transmission of the MU-RTS frame to coincide with the start of the restricted TWT SP. In the example of FIG. 11B, the non-legacy STA 1116 obtains a shortened TXOP before the start of the restricted TWT SP. The AP 1112 senses that the medium is idle for a PIFS duration from time t0 to t1 and proceeds to transmit the MU-RTS frame at time t1. In some implementations, the MU-RTS frame may identify one or more low-latency STAs (such as the low-latency STA 1114). As shown in FIG. 11B, the low-latency STA 1114 responds to the MU-RTS by sending a CTS back to the AP 1112 at time t3.

[0131]

[0151] In some implementations, the duration field (in the MAC header) of the MU-RTS frame may be used to protect latency-sensitive traffic in restricted TWT SPs. As described with reference to FIG. 8A, STAs that comply with existing versions of the IEEE 802.11 standard must postpone medium access for at least the duration indicated by the duration field. In some implementations, the duration indicated by the duration field may be greater than the duration required to transmit the MU-RTS frame. As shown in FIG. 11B, the non-legacy STA 1116 sets its NAV to the duration indicated by the duration field of the MU-RTS frame, spanning the duration from time t2 to t8. In some other implementations, the non-legacy STA 1116 may set its NAV to the duration indicated by the duration field of the CTS frame.

[0132]

[0152] In some implementations, the AP 1112 may transmit a trigger frame at time t5 following receipt of the CTS frame. In some implementations, the trigger frame may solicit a TB PPDU from one or more low-latency STAs (such as the low-latency STA 1114). As shown in FIG. 11B, the low-latency STA 904 responds to the trigger frame by transmitting UL data in a TB PPDU to the AP 1112 at time t7.

[0133]

[0153] At the end of the NAV duration, at time t8, the non-legacy STA 1116 may contend for medium access. However, the non-legacy STA 1116 senses that the medium is busy at time t8 due to the transmission of the TB PPDU. Thus, the non-legacy STA 1116 refrains from accessing the shared medium for the duration of the TB PPDU. After the transmission of the TB PPDU is completed, at time t9, the non-legacy STA 1116 may contend once again for medium access. As shown in FIG. 11B, the non-legacy STA 1116 may contend for medium access from time t9 to t 10 The medium is sensed as being idle for the AIFS duration up to time t 10 From 11 Count down the RBO duration until time t 11 From 12 Get TXOP until

[0134]

[0154] In some implementations, the MU-RTS may identify multiple low-latency STAs (not shown for simplicity). In such implementations, each low-latency STA may transmit a respective CTS frame from time t3 to t4 in response to the MU-RTS frame. In some implementations, the trigger frame may be used to solicit TB PPDUs from multiple low-latency STAs (not shown for simplicity). In such implementations, multiple low-latency STAs may transmit their respective UL data to the AP 1112 simultaneously in a TB PPDU (from time t7 to t9).

[0135]

[0155] In some implementations, the AP 1112 may poll the low-latency STAs prior to the start of the restricted TWT SP to determine which (if any) of the STAs have UL data to send. For example, the AP 1112 may send a BSRP trigger frame to the low-latency STAs associated with the restricted TWT SP. Each low-latency STA responds to the BSRP trigger frame by sending back a BSR to the AP 1112 indicating the amount of UL data buffered by the STA. The AP 1112 may use the information carried in each BSR to determine resource allocation for the TB PPDU.

[0136]

[0156] In some implementations, the NAV duration indicated by the duration field of the MU-RTS frame may be selected to balance the efficiency of medium utilization and the latency gain for latency-sensitive traffic. In the example of FIG. 11B, the NAV duration is configured to end before the end of the TB PPDU. However, in some other implementations, the NAV duration may be configured to extend beyond the duration of the TB PPDU.

[0137]

[0157] 12 shows an illustrative flowchart 1200 illustrating example wireless communication operations. The example operations 1200 may be performed by a wireless communication device, such as any of the APs 110 or 300 of FIGS. 1 and 3, respectively.

[0138]

[0158] The wireless communication device performs a channel sensing operation indicating whether the wireless channel is busy or idle 1202. The wireless communication device further transmits a first packet over the wireless channel in response to the channel sensing operation indicating at a first time that the wireless channel associated with the restricted TWT SP is idle for a threshold duration relative to a start of the restricted TWT SP, the first packet including a duration field indicating a duration for which the wireless channel is reserved, the channel sensing operation further indicating that the wireless channel is busy at a second time after the first time less than the duration indicated by the duration field of the first packet 1204.

[0139]

[0159] In some implementations, the wireless communication device may further receive a third packet over the wireless channel from the second STA at a third time, the third time occurring after the second time and before the end of the restricted TWT SP. In some implementations, the first time may coincide with a start of the restricted TWT SP. In some implementations, the duration indicated by a duration field of the first packet may be greater than a duration required to complete transmission of the first packet. In some implementations, the threshold duration may be a PIFS duration. In some implementations, the duration between the first time and the start of the restricted TWT SP may be less than or equal to the threshold duration. In some implementations, the first packet may be a clear-to-send CTS-to-self frame.

[0140]

[0160] In some implementations, the wireless communication device may further receive a second packet over the wireless channel from a first STA associated with the restricted TWT SP at a second time. In some implementations, the first packet may be a MU-RTS frame and the second packet may be a CTS frame. In some other implementations, the first packet may be a trigger frame requesting first uplink data from the first STA and the second packet may be a TB PPDU carrying the first uplink data. In some implementations, the trigger frame may further request second uplink data from a second STA associated with the restricted TWT SP and the TB PPDU may further carry the second uplink data. In some implementations, the wireless communication device may further transmit a BSRP trigger frame to the first STA prior to the start of the restricted TWT SP and receive a BSR from the first STA in response to the BSRP trigger frame, the BSR indicating availability of the first uplink data.

[0141]

[0161] 13 shows an illustrative flowchart 1300 illustrating an example wireless communication operation. The example operation 1300 may be performed by a wireless communication device, such as any of the STAs 120a-120i of FIG. 1 or the STA 200 of FIG.

[0142]

[0162] The wireless communication device receives 1302 a first packet over a wireless channel associated with a restricted TWT SP at a first time, the first packet including a duration field indicating a duration for which the wireless channel is reserved. In some implementations, the first time may coincide with a start of the restricted TWT SP. In some implementations, the duration indicated by the duration field of the first packet may be greater than a duration required to complete transmission of the first packet. In some implementations, the duration between the first time and the start of the restricted TWT SP may be less than or equal to a PIFS duration. In some implementations, the first packet may be a CTS-to-self frame.

[0143]

[0163] The wireless communication device further transmits a second packet over the wireless channel in response to the first packet at a second time, the second time being after the first time by less than the duration indicated by the duration field of the first packet (1304). In some implementations, the second packet may be transmitted to the AP. In some other implementations, the second packet may be transmitted to the STA. In some implementations, the first packet may be a MU-RTS frame and the second packet may be a CTS frame. In some other implementations, the first packet may be a trigger frame requesting uplink data from the wireless communication device and the second packet may be a TB PPDU carrying the uplink data. In some implementations, the wireless communication device may further receive a BSRP trigger frame prior to a start of the restricted TWT SP and may transmit a BSR in response to the BSRP trigger frame, the BSR indicating availability of uplink data.

[0144]

[0164] Figure 14 shows a block diagram of an example wireless communication device 1400. In some implementations, the wireless communication device 1400 may be configured to perform the process 1200 described above with reference to Figure 12. The wireless communication device 1400 may be an example implementation of any of the APs 110 or 300 of Figures 1 and 3, respectively. More specifically, the wireless communication device 1400 may be a chip, SoC, chipset, package or device that includes at least one processor and at least one modem (e.g., a Wi-Fi (IEEE 802.11) modem or a cellular modem).

[0145]

[0165] The wireless communication device 1400 includes a receiving component 1410, a communications manager 1420, and a transmitting component 1430. The communications manager 1420 further includes a channel sensing component 1422 and a latency sensitive (LS) traffic protection component 1424. One or more portions of the components 1422-1424 may be implemented at least partially in hardware or firmware. In some implementations, at least one or more of the components 1422 or 1424 are implemented at least partially as software stored in a memory (such as memory 240 of FIG. 2 or memory 330 of FIG. 3). For example, one or more portions of the components 1422 and 1424 may be implemented as non-transitory instructions (or "code") executable by a processor (such as processor 320 of FIG. 3) to perform the functions or operations of the respective components.

[0146]

[0166] The receiving component 1410 is configured to receive RX signals from one or more other wireless communication devices, and the transmitting component 1430 is configured to transmit TX signals to one or more other wireless communication devices. The communications manager 1420 is configured to manage wireless communications with one or more other wireless communication devices. In some implementations, the channel sensing component 1422 may perform a channel sensing operation indicating whether a wireless channel is busy or idle, and the LS traffic protection component 1424 transmits a first packet over the wireless channel in response to the channel sensing operation indicating at a first time that the wireless channel associated with the restricted TWT SP is idle for a threshold duration relative to a start of the restricted TWT SP, the first packet including a duration field indicating a duration for which the wireless channel is reserved, and the channel sensing operation further indicates that the wireless channel is busy at a second time after the first time for less than the duration indicated by the duration field of the first packet.

[0147]

[0167] FIG. 15 shows a block diagram of an example wireless communication device 1500. In some implementations, the wireless communication device 1500 may be configured to perform the process 1300 described above with reference to FIG. 13. The wireless communication device 1500 may be an example implementation of any of the STAs 120a-120i of FIG. 1 or the STA 200 of FIG. 2. More specifically, the wireless communication device 1500 may be a chip, SoC, chipset, package or device including at least one processor and at least one modem (e.g., a Wi-Fi (IEEE 802.11) modem or a cellular modem).

[0148]

[0168] The wireless communication device 1500 includes a receiving component 1510, a communications manager 1520, and a transmitting component 1530. The communications manager 1520 further includes a latency sensitive (LS) traffic management component 1522. Portions of the LS traffic management component 1522 may be implemented at least partially in hardware or firmware. In some implementations, the LS traffic management component 1522 is implemented at least partially as software stored in a memory (such as memory 240 of FIG. 2 or memory 330 of FIG. 3). For example, portions of the LS traffic management component 1522 may be implemented as non-transitory instructions (or “code”) executable by a processor (such as processor 220 of FIG. 2) to perform the functions or operations of the respective components.

[0149]

[0169] The receiving component 1510 is configured to receive RX signals from one or more other wireless communication devices, and the transmitting component 1530 is configured to transmit TX signals to one or more other wireless communication devices. In some implementations, the receiving component 1510 may receive, at a first time, over a wireless channel associated with a restricted TWT SP, a first packet including a duration field indicating a duration for which the wireless channel is reserved. In some implementations, the transmitting component 1530 may transmit, at a second time, over the wireless channel in response to the first packet, a second packet that is less than the duration indicated by the duration field of the first packet after the first time.

[0150]

[0170] The following numbered clauses describe example implementations. 1. A method for wireless communication by a wireless communication device, comprising: performing a channel sensing operation indicating whether a wireless channel is busy or idle; and transmitting a first packet over the wireless channel at a first time in response to a channel sensing operation indicating that the wireless channel associated with a restricted target wake time (TWT) service period (SP) is idle for a threshold duration relative to a start of a restricted TWT SP, the first packet including a duration field indicating a duration for which the wireless channel is reserved, the channel sensing operation further indicating that the wireless channel is busy at a second time after the first time less than the duration indicated by the duration field of the first packet. 2. The method of claim 1, wherein the first time coincides with the start of a restricted TWT SP. 3. The method of claim 1 or 2, wherein the duration indicated by the duration field of the first packet is greater than the duration required to complete transmission of the first packet. 4. The method of any one of clauses 1 to 3, wherein the threshold duration is a point coordination function (PCF) interframe space (PIFS) duration. 5. The method of any one of clauses 1-4, wherein the duration between the first time and the start of the limited TWT SP is less than or equal to a threshold duration. 6. The method of any one of clauses 1-5, further comprising receiving a second packet over the wireless channel from a first wireless station (STA) associated with the restricted TWT SP at a second time. 7. The method of any one of clauses 1-6, wherein the first packet comprises a clear to send (CTS) frame. 8. The method of any one of clauses 1-6, wherein the first packet comprises a multi-user (MU) request to send (RTS) frame and the second packet comprises a CTS frame. 9. The method of any one of clauses 1 to 6, wherein the first packet comprises a trigger frame requesting first uplink data from the first STA, and the second packet is a trigger-based (TB) Physical Layer Convergence Protocol (PLCP) Protocol Data Unit (PPDU) carrying the first uplink data. 10. The method of any one of clauses 1-6 or 9, wherein the trigger frame further requests second uplink data from a second STA associated with the restricted TWT SP, and the TB PPDU further carries the second uplink data. 11. Sending a buffer status report poll (BSRP) trigger frame to the first STA before the start of the restricted TWT SP; The method of any one of clauses 1 to 6, 9, or 10, further comprising receiving a buffer status report (BSR) from the first STA in response to the BSRP trigger frame, the BSR indicating availability of the first uplink data. 12. The method of any one of clauses 1-11, further comprising receiving a third packet over the wireless channel from the second STA at a third time, the third time occurring after the second time and before the end of the restricted TWT SP. 13. A wireless communication device, comprising: a processing system configured to perform a channel sensing operation to indicate whether a wireless channel is busy or idle; at least one interface, the at least one interface configured to transmit a first packet over the wireless channel in response to a channel sensing operation indicating, at a first time, that a wireless channel associated with a restricted target wake time (TWT) service period (SP) is idle for a threshold duration relative to a start of a restricted TWT SP, the first packet including a duration field indicating a duration for which the wireless channel is reserved, the channel sensing operation further indicating that the wireless channel is busy at a second time after the first time less than the duration indicated by the duration field of the first packet. 14. The wireless communication device of clause 13, wherein the first packet comprises a clear to send (CTS) frame to self. 15. The wireless communication device of clause 13, wherein the at least one interface is further configured to receive a second packet over the wireless channel at a second time from a wireless station (STA) associated with the restricted TWT SP, the first packet comprising a multi-user (MU) request to send (RTS) frame and the second packet comprising a CTS frame. 16. The wireless communications device of clause 13, wherein the at least one interface is further configured to receive a second packet over the wireless channel from a STA associated with the restricted TWT SP at a second time, the first packet comprising a trigger frame requesting uplink data from the STA, and the second packet being a trigger-based (TB) physical layer convergence protocol (PLCP) protocol data unit (PPDU) carrying the uplink data. 17. A method performed by a wireless communication device, comprising: receiving, at a first time, a first packet over a wireless channel associated with a limited target wake time (TWT) service period (SP), the first packet including a duration field indicating a duration for which the wireless channel is reserved; and transmitting, at a second time, over the wireless channel in response to the first packet, a second packet that is less than a duration indicated by a duration field of the first packet after the first time. 18. The method of claim 17, wherein the first time coincides with the start of a restricted TWT SP. 19. The method of any one of clauses 17 to 18, wherein the duration indicated by the duration field of the first packet is greater than the duration required to complete transmission of the first packet. 20. The method of any one of clauses 17 to 19, wherein the duration between the first time and the start of the restricted TWT SP is less than or equal to a point coordination function (PCF) interframe space (PIFS) duration. 21. The method of any one of clauses 17-20, wherein the first packet comprises a clear to send (CTS) frame. 22. The method of any one of clauses 17-20, wherein the first packet comprises a multi-user (MU) request to send (RTS) frame and the second packet comprises a CTS frame. 23. The method of any one of clauses 17-20, wherein the first packet comprises a trigger frame requesting uplink data from the wireless communication device, and the second packet is a trigger-based (TB) Physical Layer Convergence Protocol (PLCP) Protocol Data Unit (PPDU) carrying the uplink data. 24. Receiving a Buffer Status Report Poll (BSRP) trigger frame prior to the start of a restricted TWT SP; 24. The method of any one of clauses 17-20 or 23, further comprising: transmitting a Buffer Status Report (BSR) in response to the BSRP trigger frame, the BSR indicating availability of uplink data. 25. The method of any one of clauses 17 to 24, wherein the second packet is transmitted to an access point (AP). 26. The method of any one of clauses 17-24, wherein the second packet is transmitted to a wireless station (STA). 27. A wireless communication device, comprising: A processing system; and an interface, the interface comprising: receiving, at a first time, a first packet over a wireless channel associated with a limited target wake time (TWT) service period (SP), the first packet including a duration field indicating a duration for which the wireless channel is reserved; and and a wireless communication device configured to transmit, at a second time, over a wireless channel in response to the first packet, a second packet that is less than a duration indicated by a duration field of the first packet after the first time. 28. The wireless communication device of clause 27, wherein the first packet comprises a clear to send (CTS) frame to self. 29. The wireless communications device of clause 27, wherein the first packet comprises a multi-user (MU) request to send (RTS) frame and the second packet comprises a CTS frame. 30. The wireless communication device of clause 27, wherein the first packet comprises a trigger frame requesting uplink data from the wireless communication device, and the second packet is a trigger-based (TB) physical layer convergence protocol (PLCP) protocol data unit (PPDU) carrying the uplink data.

[0151]

[0171] As used herein, phrases referring to "at least one of" or "one or more of" a list of items refer to any combination of those items, including single members. For example, "at least one of a, b, or c" is intended to encompass the possibilities of a only, b only, c only, a combination of a and b, a combination of a and c, a combination of b and c, and a combination of a, b, and c.

[0152]

[0172] The various example components, logic, logic blocks, modules, circuits, operations, and algorithmic processes described with respect to implementations disclosed herein may be implemented as electronic hardware, firmware, software, or combinations of hardware, firmware, or software, including the structures disclosed herein and structural equivalents thereof. The interchangeability of hardware, firmware, and software has been described generally in terms of functionality and illustrated in the various example components, blocks, modules, circuits, and processes described above. Whether such functionality is implemented in hardware, firmware, or software depends on the particular application and design constraints imposed on the overall system.

[0153]

[0173] Various modifications of the implementations described in this disclosure may be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other implementations without departing from the spirit or scope of the present disclosure. Thus, the claims are not intended to be limited to the implementations shown herein, but are to be accorded the widest scope consistent with the present disclosure, the principles and novel features disclosed herein.

[0154]

[0174] Moreover, various features that are described herein in the context of separate implementations may also be implemented in combination in a single implementation. Conversely, various features that are described in the context of a single implementation may also be implemented in multiple implementations separately or in any suitable subcombination. Thus, although features may be described above as working in a particular combination, and may even initially be claimed as such, in some cases one or more features from a claimed combination may be deleted from that combination, and the claimed combination may be directed to a subcombination or a variation of the subcombination.

[0155]

[0175] Similarly, although operations are shown in the figures in a particular order, this should not be understood as requiring such operations to be performed in the particular order or sequential order shown, or that all of the operations shown be performed, to achieve a desired result. Furthermore, the figures may generally illustrate one or more exemplary processes in the form of a flow chart or flow diagram. However, other operations not shown may be incorporated into the generally illustrated exemplary process. 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 implementations described above should not be understood as requiring such separation in all implementations, and it should be understood that the program components and systems described may generally be integrated together in a single software product or packaged in multiple software products.

Claims

1. 1. A method performed by a wireless communication device, comprising: performing a channel sensing operation indicating whether the wireless channel is busy or idle; transmitting a first packet over a wireless channel associated with a restricted target wake time (TWT) service period (SP) at a first time in response to the channel sensing operation indicating that the wireless channel associated with the restricted TWT SP is idle for a threshold duration relative to a start of the restricted TWT SP, the first packet including a duration field indicating a duration for which the wireless channel is reserved, the duration being less than a second duration of the restricted TWT SP, the channel sensing operation further indicating that the wireless channel is busy at a second time after the first time for less than the duration indicated by the duration field of the first packet, and the first packet comprising a clear to send (CTS) frame.

2. The method of claim 1 , wherein the first time coincides with the start of the restricted TWT SP.

3. 2. The method of claim 1, wherein the duration indicated by the duration field of the first packet is greater than a duration required to complete the transmission of the first packet.

4. The method of claim 1 , wherein the threshold duration is a point coordination function (PCF) interframe space (PIFS) duration.

5. The method of claim 1 , wherein the duration between the first time and the start of the restricted TWT SP is less than or equal to the threshold duration.

6. 2. The method of claim 1, further comprising receiving a second packet over the wireless channel from a first wireless station (STA) associated with the restricted TWT SP at the second time.

7. 7. The method of claim 6, wherein the first packet comprises a multi-user (MU) request to send (RTS) frame and the second packet comprises a CTS frame.

8. 7. The method of claim 6, wherein the first packet comprises a trigger frame requesting first uplink data from the first STA, and the second packet is a trigger-based (TB) Physical Layer Convergence Protocol (PLCP) Protocol Data Unit (PPDU) carrying the first uplink data.

9. 10. The method of claim 8, wherein the trigger frame further requests second uplink data from a second STA associated with the restricted TWT SP, and the TB PPDU further carries the second uplink data.

10. transmitting a Buffer Status Report Poll (BSRP) trigger frame to the first STA prior to the start of the restricted TWT SP; 10. The method of claim 8, further comprising: receiving a Buffer Status Report (BSR) from the first STA in response to the BSRP trigger frame, the BSR indicating availability of the first uplink data.

11. 2. The method of claim 1, further comprising receiving a third packet from a second STA over the wireless channel at a third time, the third time occurring after the second time and before an end of the restricted TWT SP.

12. 1. A wireless communication device, comprising: a processing system configured to perform a channel sensing operation to indicate whether the wireless channel is busy or idle; at least one interface configured to transmit a first packet over a wireless channel associated with a restricted target wake time (TWT) service period (SP) at a first time in response to the channel sensing operation indicating that the wireless channel associated with the restricted TWT SP is idle for a threshold duration relative to a start of the restricted TWT SP, the first packet including a duration field indicating a duration for which the wireless channel is reserved, the duration being less than a second duration of the restricted TWT SP, the channel sensing operation further indicating that the wireless channel is busy at a second time after the first time for less than the duration indicated by the duration field of the first packet, and the first packet comprising a clear to send (CTS) frame.

13. 1. A method performed by a wireless communication device, comprising: receiving a first packet at a first time over a wireless channel associated with a restricted target wake time (TWT) service period (SP), the first packet including a duration field indicating a duration for which the wireless channel is reserved, the duration being less than a second duration of the restricted TWT SP, the first packet comprising a clear to send (CTS) frame; transmitting a second packet over the wireless channel in response to the first packet at a second time, the second time being after the first time by less than the duration indicated by the duration field of the first packet.

14. The method of claim 13 , wherein the first time coincides with a start of the restricted TWT SP.

15. 1. A wireless communication device, comprising: A processing system; and an interface, the interface comprising: receiving a first packet at a first time over a wireless channel associated with a restricted target wake time (TWT) service period (SP), the first packet including a duration field indicating a duration for which the wireless channel is reserved, the duration being less than a second duration of the restricted TWT SP, the first packet comprising a clear to send (CTS) frame; transmitting a second packet over the wireless channel in response to the first packet at a second time, the second time being after the first time by less than the duration indicated by the duration field of the first packet.

16. A wireless communication device configured to:

Images