Method and apparatus for low latency enhancements for wireless networks

Abstract

Methods and apparatuses for low latency enhancements for wireless networks are disclosed that can be used to establish restricted target wake time (TWT) sessions over a wireless medium. In some implementations, an access point (AP) establishes a restricted TWT session for one or more wireless stations (STAs) associated with latency sensitive traffic, the restricted TWT session including a restricted TWT service period (SP) during which the AP reserves access to the wireless medium for only the one or more STAs associated with the latency sensitive traffic. The AP transmits a clear to send (CTS) frame at the start of each restricted TWT SP, the CTS frame indicating to other STAs that the wireless medium is unavailable for the duration of the corresponding restricted TWT SP. The AP transmits latency sensitive data to or receives latency sensitive data from the one or more STAs during at least one restricted TWT SP.

Description

[0001] This application is a divisional application of Chinese patent application No. 202180051536.4 (PCT International Application No. PCT / US2021 / 047882) filed on August 27, 2021, entitled "Low Latency Enhancement for Wireless Networks".

[0002] Cross-references to related applications

[0003] This patent application claims priority to U.S. Provisional Patent Application No. 63 / 072,084, filed August 28, 2020, entitled "LOW LATENCY ENHANCEMENTS FOR A WIRELESS NETWORK," and U.S. Non-Provisional Patent Application No. 17 / 446,085, filed August 26, 2021, all of which are assigned to the assignee of this application. All disclosures of the prior applications are considered part of this patent application and are incorporated herein by reference. Technical Field

[0004] This disclosure generally relates to wireless communications, and more particularly to ensuring that a specific level of data throughput is maintained for latency-sensitive traffic. Background Technology

[0005] A Wireless Local Area Network (WLAN) can be formed by one or more Access Points (APs) that provide a shared wireless communication medium for use by several client devices (also known as stations (STAs)). The basic building block of a WLAN conforming to the IEEE 802.11 family of standards is the Basic Service Set (BSS) managed by the AP. Each BSS is identified by a Basic Service Set Identifier (BSSID) advertised by the AP. The AP periodically broadcasts beacon frames to enable any STA within the AP's wireless range to establish or maintain a communication link with the WLAN.

[0006] Some traffic (such as gaming traffic) has strict end-to-end latency and packet loss requirements and can be classified as low-latency or latency-sensitive traffic. It is expected that the WLAN can identify latency-sensitive traffic and ensure that it can be handled without violating any associated latency, packet loss, or data throughput requirements. Summary of the Invention

[0007] The systems, methods, and apparatus disclosed herein each have several innovative aspects, and no single aspect is solely responsible for the desired properties disclosed herein.

[0008] One innovative aspect of the subject matter described in this disclosure can be implemented as a method for wireless communication. In some implementations, the method can be performed by a wireless communication device operating as an access point (AP) and may include: establishing a restricted target wake-up time (TWT) session over a wireless medium for one or more radio stations (STAs) associated with time-sensitive traffic. The restricted TWT session may include one or more restricted TWT service periods (SPs) for communicating only with the one or more STAs associated with time-sensitive traffic over the wireless medium. The method may include transmitting a clear transmit (CTS) frame over the wireless medium at the beginning of each of the one or more restricted TWT SPs. The CTS frame may indicate to other STAs that the wireless medium is busy or unavailable during the duration of the corresponding restricted TWT SP. The method may include transmitting or receiving time-sensitive data from the one or more STAs during at least one of the one or more restricted TWT SPs. In some implementations, the Receiver Address (RA) of a CTS frame can be set to a configured Media Access Control (MAC) address that indicates that a STA belonging to that restricted TWT session is permitted access to the radio medium during the corresponding restricted TWT SP. In some instances, the configured MAC address may correspond to a configured Network Assignment Vector (NAV) setting used for other STAs.

[0009] In some implementations, the method may further include instructing each of the other STAs to terminate a Transmission Opportunity (TXOP) on the radio medium at or before the start of each of the one or more restricted TWT SPs. In some other implementations, the method may further include instructing each of the other STAs not to be permitted access to the radio medium during each of the one or more restricted TWT SPs. In some instances, this instruction may be included in the TWT parameter information field of a TWT element carried in one or more beacon frames transmitted from the AP.

[0010] In some implementations, the method may further include: detecting that no data transmission from the one or more STAs has occurred for a period of time or longer during the corresponding restricted TWT SP; and, based on the detection that no data transmission from the one or more STAs has occurred, releasing control of the wireless medium for the remainder of the corresponding restricted TWT SP. In some instances, releasing control of the wireless medium may include transmitting a contention-free end (CF-END) frame on the wireless medium.

[0011] In some implementations, establishing a restricted TWT session may include: transmitting a frame indicating a delay-sensitive traffic priority associated with the restricted TWT session; and receiving from each of the one or more STAs a request to become a member of the restricted TWT session based on the indicated delay-sensitive traffic priority. In some instances, the indicated delay-sensitive traffic priority may correspond to one or more selected traffic identifiers (TIDs). For example, the one or more selected TIDs may be associated with a Voice Access Class (AC_VO). In other instances, the indicated delay-sensitive traffic priority may correspond to a selected traffic flow. For example, the selected traffic flow may be identified by an IP 5-tuple or an IPv6 flow label.

[0012] In some implementations, the frame may be one or more of a beacon frame, probe response frame, association frame, or reassociation frame, and may include one or more TWT parameters associated with the restricted TWT session. In some instances, the one or more TWT parameters may be included in the TWT parameter information field of a TWT element carried in one or more beacon frames transmitted from the AP. In some other instances, the one or more TWT parameters may indicate whether the restricted TWT session is a peer-to-peer TWT session. Additionally or alternatively, the one or more TWT parameters may indicate whether the restricted TWT session is full.

[0013] In some other implementations, establishing a restricted TWT session may further include: verifying that each of the one or more STAs is associated with an indicated delay-sensitive traffic priority, and adding the one or more STAs to the restricted TWT session based on the corresponding verification of the STAs. Additionally or alternatively, establishing a restricted TWT session may further include: determining the periodicity of delay-sensitive traffic associated with at least one of the one or more STAs; and configuring TWT intervals based on the determined periodicity.

[0014] Another inventive aspect of the subject matter described in this disclosure can be implemented in a wireless communication device operating as an access point (AP). The AP may include at least one modem, at least one processor communicatively coupled to the at least one modem, and at least one memory communicatively coupled to the at least one processor. The at least one memory may store processor-readable code configured, when executed by the at least one processor in conjunction with the at least one modem, to establish a restricted time-sensitive traffic (TWT) session over a wireless medium for one or more STAs associated with time-sensitive traffic. The restricted TWT session may include one or more restricted TWT SPs for communicating only with the one or more STAs associated with time-sensitive traffic over the wireless medium. Execution of the processor-readable code may be configured to transmit a CTS frame over the wireless medium at the beginning of each of the one or more restricted TWT SPs. The CTS frame may indicate to other STAs that the wireless medium is unavailable during the duration of the corresponding restricted TWT SP. Execution of the processor-readable code may be configured to transmit or receive time-sensitive data from the one or more STAs during at least one of the one or more restricted TWT SPs. In some implementations, the RA of a CTS frame can be set to a configured MAC address that indicates that a STA belonging to that restricted TWT session is permitted access to the radio medium during the corresponding restricted TWT SP. In some instances, the configured MAC address may correspond to a configured NAV setting used for other STAs.

[0015] In some implementations, the execution of the processor-readable code can also be configured to instruct each of the other STAs to terminate the TXOP on the radio medium at or before the start of each of the one or more restricted TWT SPs. In some other implementations, the execution of the processor-readable code can also be configured to instruct each of the other STAs not to be permitted access to the radio medium during each of the one or more restricted TWT SPs. In some instances, this instruction may be included in the TWT parameter information field of the TWT element carried in one or more beacon frames transmitted from the AP.

[0016] In some implementations, the execution of the processor-readable code can also be configured to: detect that no data transmission from the one or more STAs has occurred for a period of time or longer during the corresponding restricted TWTSP; and, based on the detection that no data transmission from the one or more STAs has occurred, release control of the wireless medium for the remainder of the corresponding restricted TWTSP. In some instances, releasing control of the wireless medium may include transmitting a CF-END frame on the wireless medium.

[0017] In some implementations, establishing a restricted TWT session may include: transmitting a frame indicating a delay-sensitive traffic priority associated with the restricted TWT session; and receiving from each of the one or more STAs a request to become a member of the restricted TWT session based on the indicated delay-sensitive traffic priority. In some instances, the indicated delay-sensitive traffic priority may correspond to one or more selected TIDs. For example, the one or more selected TIDs may be associated with a Voice Access Class (AC_VO). In some other instances, the indicated delay-sensitive traffic priority may correspond to a selected traffic flow. For example, the selected traffic flow may be identified by an IP 5-tuple or an IPv6 flow label.

[0018] In some implementations, the frame may be one or more of a beacon frame, probe response frame, association frame, or reassociation frame, and may include one or more TWT parameters associated with the restricted TWT session. In some instances, the one or more TWT parameters may be included in the TWT parameter information field of a TWT element carried in one or more beacon frames transmitted from the AP. In some other instances, the one or more TWT parameters may indicate whether the restricted TWT session is a peer-to-peer TWT session. Additionally or alternatively, the one or more TWT parameters may indicate whether the restricted TWT session is full.

[0019] In some other implementations, establishing a restricted TWT session may further include: verifying that each of the one or more STAs is associated with an indicated delay-sensitive traffic priority, and adding the one or more STAs to the restricted TWT session based on the corresponding verification of the STAs. Additionally or alternatively, establishing a restricted TWT session may further include: determining the periodicity of delay-sensitive traffic associated with at least one of the one or more STAs; and configuring TWT intervals based on the determined periodicity.

[0020] 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 this description, the drawings, and the claims. It should be noted that the relative dimensions in the following drawings may not be drawn to scale. Attached Figure Description

[0021] Figure 1 A schematic diagram of an example wireless communication network is shown.

[0022] Figure 2A An example Protocol Data Unit (PDU) is shown that can be used for communication between an Access Point (AP) and several Stations (STAs).

[0023] Figure 2B It shows Figure 2A Example fields in the PDU.

[0024] Figure 3 An example Physical Layer Convergence Protocol (PLCP) Protocol Data Unit (PPDU) is shown that can be used for communication between an AP and several STAs.

[0025] Figure 4 A block diagram of an example wireless communication device is shown.

[0026] Figure 5A A block diagram of an example access point (AP) is shown.

[0027] Figure 5B A block diagram of an example station (STA) is shown.

[0028] Figure 6 The flowchart illustrates an example process for wireless communication supporting restricted target wake-up time (TWT) sessions, based on some implementations.

[0029] Figure 7A The flowchart illustrates an example process for supporting wireless communication for restricted TWT sessions, based on some implementations.

[0030] Figure 7B The flowchart illustrates an example process for supporting wireless communication for restricted TWT sessions, based on some implementations.

[0031] Figure 7C The flowchart illustrates an example process for supporting wireless communication for restricted TWT sessions, based on some implementations.

[0032] Figure 8 The flowchart illustrates an example process for supporting wireless communication for restricted TWT sessions, based on some implementations.

[0033] Figure 9 The flowchart illustrates an example process for supporting wireless communication for restricted TWT sessions, based on some implementations.

[0034] Figure 10 The flowchart illustrates an example process for supporting wireless communication for restricted TWT sessions, based on some implementations.

[0035] Figure 11 The flowchart illustrates an example process for supporting wireless communication for restricted TWT sessions, based on some implementations.

[0036] Figure 12 The flowchart illustrates an example process for supporting wireless communication for restricted TWT sessions, based on some implementations.

[0037] Figure 13A The diagram illustrates the timing of communication transmissions supporting restricted TWT sessions according to some implementations.

[0038] Figure 13B The diagram illustrates the timing of communication transmissions supporting restricted TWT sessions according to some other implementations.

[0039] Figure 14A An example structure of a TWT element, based on some implementations, is shown that can be used to support wireless communication for restricted TWT sessions.

[0040] Figure 14B An example structure of the broadcast TWT parameter set field, which can be used to support wireless communication for restricted TWT sessions, is shown according to some implementations.

[0041] Figure 14C An example structure of the request type field in the broadcast TWT parameter set fields, which can be used to support restricted TWT sessions according to some implementations, is shown.

[0042] Figure 15 A block diagram of an example wireless communication device based on some implementations is shown.

[0043] Similar reference numerals and naming conventions in the various figures indicate similar elements. Detailed Implementation

[0044] The following description is directed to certain implementations in order to describe the innovative aspects of this 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 following: the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard, the IEEE 802.15 standard, the Bluetooth® standard as defined by the Bluetooth Special Interest Group (SIG), or the Long Term Evolution (LTE), 3G, 4G, or 5G (New Radio (NR)) standards published by the 3GPP project. The described implementations can be implemented in any device, system, or network capable of transmitting and receiving RF signals according to one or more of the following techniques or skills: 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 implementation can also be implemented using other wireless communication protocols or RF signals suitable for use in one or more of a wireless personal area network (WPAN), wireless local area network (WLAN), wireless wide area network (WWAN), or Internet of Things (IoT) network.

[0045] Various implementations generally involve Restricted Target Wake-Up Time (TWT) sessions over a radio medium. Some implementations more specifically involve establishing restricted TWT sessions for radio stations with or associated with latency-sensitive traffic, which has strict end-to-end latency and packet loss requirements. According to some aspects of this disclosure, an AP can establish or schedule restricted Target Wake-Up Time (TWT) sessions over a radio medium for one or more radio stations (STAs) associated with latency-sensitive traffic. A restricted TWT session may include multiple restricted TWT Service Periods (SPs) for communicating over the radio medium only with one or more STAs associated with latency-sensitive traffic. The AP may transmit a Clear Transmit (CTS) frame over the radio medium at the beginning of each restricted TWT SP to prevent contention over the radio medium. In some instances, the AP may set the Receiver Address (RA) of the CTS frame to a configured Media Access Control (MAC) address that indicates that an STA belonging to a restricted TWT session is allowed access to the radio medium during the corresponding restricted TWT SP, and therefore the CTS frame may be ignored. Setting the RA of a CTS frame to the configured MAC address can also indicate a specific value that other stations not belonging to the restricted TWT session can set to their respective Network Assignment Vectors (NAVs).

[0046] In some implementations, the AP may transmit frames that include one or more TWT parameters associated with the restricted TWT session. This frame may be a beacon frame, probe response frame, association frame, or reassociation frame, and may also indicate a latency-sensitive traffic priority associated with the restricted TWT session. In some instances, the indicated latency-sensitive traffic priority may correspond to one or more selected traffic identifiers (TIDs). The selected TIDs may be associated with a specific access class (such as a voice access class), may correspond to a selected traffic flow, or may correspond to a configured tag.

[0047] Specific aspects of the subject matter described in this disclosure can be implemented to achieve one or more of the following potential advantages. As discussed, traffic originating from many real-time applications can have stringent latency requirements (e.g., very low average latency, worst-case latency on the order of milliseconds to tens of milliseconds, and minimal jitter). In some aspects, the described techniques provide enhanced media access and resource reservation mechanisms. For example, by establishing restricted TWT sessions for STAs having or associated with latency-sensitive traffic (such as gaming traffic), the AP can provide STAs as members of the restricted TWT sessions with more predictable latency, reduced worst-case latency, and reduced jitter. In this way, the AP can ensure that such STAs have sufficient access to the radio medium to meet the stringent end-to-end latency and packet loss requirements associated with latency-sensitive traffic.

[0048] Figure 1 A block diagram of an example wireless communication network, such as a wireless local area network (WLAN) 100, is shown. In some respects, the wireless communication network may be referred to as a Wi-Fi network. For example, WLAN 100 may be a network that implements at least one of the IEEE 802.11 standard family, such as standards defined by the IEEE 802.11-2016 specification or its amendments, including but not limited to 802.11ah, 802.11ad, 802.11ay, 802.11ax, 802.11az, 802.11ba, and 802.11be. WLAN 100 may include numerous wireless communication devices, such as access points (APs) 102 and multiple stations (STAs) 104. Although only one AP 102 is shown, WLAN 100 may also include multiple APs 102.

[0049] Each STA 104 may also be referred to as a mobile station (MS), mobile device, mobile handheld device, wireless handheld device, access terminal (AT), user equipment (UE), subscriber station (SS), or subscriber unit, and other possibilities. STA 104 may represent a variety of devices such as mobile phones, personal digital assistants (PDAs), other handheld devices, netbooks, laptops, tablets, laptops, display devices (e.g., TVs, computer monitors, navigation systems, etc.), music or other audio or stereo devices, remote control devices (“remote controllers”), printers, kitchen or other household appliances, key fobs (e.g., for passive keyless entry and start (PKES) systems), and other possibilities.

[0050] A single AP 102 and its associated set of STAs 104 may be referred to as a Basic Service Set (BSS), which is managed by the corresponding AP 102. Figure 1 Additionally, an example coverage area 106 of AP 102 is shown, which may represent the Basic Service Area (BSA) of WLAN 100. The BSA can be identified to users by a Service Set Identifier (SSID) and to other devices by a Basic Service Set Identifier (BSSID), which may be the Media Access Control (MAC) address of AP 102. AP 102 periodically broadcasts a beacon frame (“beacon”) including the BSSID to enable any STA 104 within the wireless range of AP 102 to “associate” or reassociate with AP 102 to establish or maintain a corresponding communication link 108 with AP 102 (hereinafter also referred to as a “Wi-Fi link”). For example, the beacon may include an identifier of the primary channel used by the corresponding AP 102 and a timing synchronization function for establishing or maintaining timing synchronization with AP 102. AP102 can provide access to external networks to each STA 104 in the WLAN via the corresponding communication link 108.

[0051] In order to establish a communication link 108 with AP 102, each STA 104 is configured to perform passive or active scanning operations (“scanning”) on frequency channels in one or more frequency bands (e.g., 2.4 GHz, 5.0 GHz, 6.0 GHz, or 60 GHz bands). To perform a passive scan, STA 104 listens for beacons transmitted by the corresponding AP 102 at periodic time intervals (referred to as Target Beacon Transmission Time (TBTT) – measured in units of time (TU), where one TU can be equal to 1024 microseconds (µs)). To perform an active scan, STA 104 generates probe requests and transmits these requests sequentially on each channel to be scanned, and listens for probe responses from AP 102. Each STA 104 can be configured to identify or select an AP 102 to associate with based on scan information obtained through passive or active scanning, and perform authentication and association operations to establish a communication link 108 with the selected AP 102. At the end of the association operation, AP 102 assigns an Association Identifier (AID) to STA 104, which AP 102 uses to track STA 104.

[0052] As wireless networks become increasingly prevalent, STA 104 can have the opportunity to choose from one of many BSSs within its range or from multiple APs 102 that together form an Extended Service Set (ESS) (comprising multiple connected BSSs). The extended network station associated with WLAN 100 can be connected to a wired or wireless distribution system that allows multiple APs 102 to be connected in such an ESS. Thus, STA 104 can be covered by more than one AP 102 and can be associated with different APs 102 at different times for different transmissions. Additionally, after being associated with an AP 102, STA 104 can also be configured to periodically scan its surroundings to find a more suitable AP 102 to associate with. For example, a STA 104 that is moving relative to its associated AP 102 can perform a "roaming" scan to find another AP 102 with more suitable network characteristics, such as a larger Received Signal Strength Indicator (RSSI) or reduced traffic load.

[0053] In some scenarios, STA 104 can form a network without AP 102 or other equipment besides STA 104 itself. An example of such a network is an ad hoc network (or wireless ad hoc network). Ad hoc networks are alternatively referred to as mesh networks or peer-to-peer (P2P) networks. In some scenarios, ad hoc networks can be implemented within a larger wireless network, such as WLAN 100. In such implementations, while STA 104 can communicate with each other via AP 102 using communication link 108, STA 104 can also communicate directly with each other via direct wireless link 110. Furthermore, two STA 104 can communicate via direct communication link 110, regardless of whether the two STA 104 are associated with and served by the same AP 102. In such ad hoc systems, one or more STA 104 can assume the role played by AP 102 in the BSS. Such STA 104 can be referred to as the group owner (GO) and can coordinate transmissions within the ad hoc network. Examples of direct wireless links 110 include Wi-Fi Direct connections, connections established using Wi-Fi Tunneling Direct Link Establishment (TDLS) links, and other P2P group connections.

[0054] AP 102 and STA 104 can operate and communicate (via the corresponding communication link 108) according to the IEEE 802.11 standard family, such as standards defined by the IEEE 802.11-2016 specification or its revisions, including but not limited to 802.11ah, 802.11ad, 802.11ay, 802.11ax, 802.11az, 802.11ba, and 802.11be. These standards define the WLAN radio and baseband protocols used for the PHY and Media Access Control (MAC) layers. AP 102 and STA 104 transmit and receive wireless communications (also referred to below as "Wi-Fi communication") to and from each other in the form of Physical Layer Convergence Protocol (PLCP) Protocol Data Units (PPDUs). AP 102 and STA 104 in WLAN 100 can transmit PPDUs on unlicensed spectrum, which can be a portion of the spectrum including bands traditionally used by Wi-Fi technologies, such as the 2.4 GHz band, 5.0 GHz band, 60 GHz band, 3.6 GHz band, and 900 MHz band. Some implementations of AP 102 and STA 104 described herein can also communicate in other bands, such as the 6.0 GHz band, that can support both licensed and unlicensed communication. AP 102 and STA 104 can also be configured to communicate on other bands, such as shared licensed bands, where multiple operators may have licenses to operate in one or more of the same or overlapping bands.

[0055] Each frequency band may include multiple sub-bands or frequency channels. For example, PPDUs conforming to revisions of the IEEE 802.11n, 802.11ac, and 802.11ax standards can be transmitted in the 2.4 GHz and 5.0 GHz frequency bands, where each band is divided into multiple 20 MHz channels. Thus, these PPDUs are transmitted on physical channels with a minimum bandwidth of 20 MHz, but larger channels can be formed through channel bonding. For example, PPDUs can be transmitted on physical channels with bandwidths of 40 MHz, 80 MHz, 160 MHz, or 320 MHz by bonding multiple 20 MHz channels together.

[0056] Each PPDU is a composite structure comprising a PHY preamble and a payload in the form of a PLCP Service Data Unit (PSDU). The information provided in the preamble can be used by the receiving equipment to decode subsequent data in the PSDU. In instances where the PPDU is transmitted over a bonded channel, the preamble field may be copied and transmitted in each of the multiple component channels. The PHY preamble may include both a legacy portion (or "legacy preamble") and a non-legacy portion (or "non-legacy preamble"). The legacy preamble can be used for packet detection, automatic gain control, and channel estimation, among other applications. The legacy preamble is also generally used to maintain compatibility with legacy equipment. The format, decoding, and information provided in the non-legacy portion of the preamble are based on the specific IEEE 802.11 protocol to be used for transmitting the payload.

[0057] Figure 2AAn example Protocol Data Unit (PDU) 200 is shown that can be used for communication between an AP and several STAs. For example, PDU 200 can be configured as a PPDU. As shown, PDU 200 includes a PHY preamble 202 and a PHY payload 204. For example, the PHY preamble 202 may include a legacy portion, which itself includes a legacy short training field (L-STF) 206, a legacy long training field (L-LTF) 208, and a legacy signaling field (L-SIG) 210. The PHY preamble 202 may also include a non-legacy portion (not shown). L-STF 206 generally enables the receiver equipment to perform automatic gain control (AGC) and coarse timing and frequency estimation. L-LTF 208 generally enables the receiver equipment to perform fine timing and frequency estimation, and also to estimate the radio channel. L-SIG 210 generally enables the receiver equipment to determine the duration of the PDU and use the determined duration to avoid transmission over the PDU. For example, L-STF 206, L-LTF 208, and L-SIG 210 can be modulated according to a binary phase shift keying (BPSK) modulation scheme. Payload 204 can be modulated according to a BPSK modulation scheme, a quadrature BPSK (Q-BPSK) modulation scheme, a quadrature amplitude modulation (QAM) modulation scheme, or another appropriate modulation scheme. Payload 204 can generally carry higher-layer data (e.g., in the form of Media Access Control (MAC) Protocol Data Units (MPDUs) or Aggregated MPDUs (A-MPDUs).

[0058] Figure 2B It shows Figure 2A Example L-SIG 220 in a PDU. L-SIG 220 includes a data rate field 222, reserved (R) bits 224, a length field 226, parity bits 228, and a tail field 230. The data rate field 222 indicates the data rate (note that the data rate indicated in the data rate field 222 may not be the actual data rate of the data carried in the payload 204). The length field 226 indicates the packet length, for example, in bytes. The parity bits 228 are used to detect bit errors. The tail field 230 includes tail bits that are used by the receiving device to terminate the operation of the decoder (e.g., the Viterbi decoder). The receiving device uses the data rate and length indicated in the data rate field 222 and the length field 226 to determine the packet duration, for example, in microseconds (µs).

[0059] Figure 3An example PPDU 300 is shown that can be used for communication between AP 102 and several STAs 104. As described above, each PPDU 300 includes a PHY preamble 302 and a PSDU 304. Each PSDU 304 may carry one or more MAC Protocol Data Units (MPDUs). For example, each PSDU 304 may carry an aggregated MPDU (A-MPDU) 306, which includes an aggregation of multiple MPDU subframes 308. Each MPDU subframe 308 may carry an MPDU 310, which may include a MAC delimiter 312 and a MAC header 314 preceding the accompanying frame body 316, which includes the data portion or "payload" of the MPDU 310. The frame body 316 may carry one or more MAC Service Data Unit (MSDU) subframes. For example, the frame body 316 may carry an aggregated MSDU (A-MSDU) 322, which includes multiple MSDU subframes 324. Each MSDU subframe 324 contains a corresponding MSDU 326, which includes a subframe header 328, a frame body 330, and one or more padding bits 332.

[0060] Referring back to MPDU 310, MAC header 314 may include several fields containing information defining or indicating the characteristics or attributes of the data encapsulated within frame body 316. MAC header 314 may also include several fields indicating the address of the data encapsulated within frame body 316. For example, MAC header 314 may include a combination of source address, sender address, receiver address, or destination address. MAC header 314 may include a frame control field containing control information. The frame control field specifies the frame type, such as a data frame, control frame, or management frame. MAC header 314 may further include a duration field indicating the duration from the end of the PPDU until the acknowledgment (ACK) of the last PPDU to be transmitted by the wireless communication device (e.g., block ACK (BA) in the case of an A-MPDU). The duration field is used to preserve the indicated duration of the wireless medium, thereby establishing NAV. Each MPDU 310 may also include a Frame Check Sequence (FCS) field 318 for error detection. For example, FCS field 318 may include cyclic redundancy check (CRC), and may be followed by one or more padding bits 320.

[0061] As described above, AP 102 and STA 104 can support multi-user (MU) communication. That is, concurrent transmission from one device to each of multiple devices (e.g., multiple simultaneous downlink (DL) communications from AP 102 to corresponding STA 104s), or concurrent transmission from multiple devices to a single device (e.g., multiple simultaneous uplink (UL) transmissions from corresponding STA 104s to AP 102). To support MU transmission, AP 102 and STA 104 can utilize multi-user multiple-input multiple-output (MU-MIMO) and multi-user orthogonal frequency division multiple access (MU-OFDMA) technologies.

[0062] In the MU-OFDMA scheme, the available spectrum of the radio channel can be divided into multiple resource elements (RUs), each comprising several different frequency subcarriers (“frequency modulo”). Different RUs can be allocated by AP 102 at specific times or assigned to different STAs 104. The size and distribution of RUs are referred to as RU allocation. In some implementations, RUs can be allocated in 2 MHz intervals, and thus, the smallest RU can include 26 frequency moduloes, comprising 24 data frequency moduloes and 2 pilot frequency moduloes. Therefore, in a 20 MHz channel, up to 9 RUs (such as 2 MHz, 26 frequency modulo RUs) can be allocated (because some frequency moduloes are reserved for other purposes). Similarly, in a 160 MHz channel, up to 74 RUs can be allocated. Larger RUs of 52, 106, 242, 484, and 996 frequency moduloes can also be allocated. Adjacent RUs can be separated by empty subcarriers (such as DC subcarriers) to reduce interference between adjacent RUs, reduce receiver DC offset, and avoid leakage of the transmit center frequency.

[0063] For UL MU transmissions, AP 102 can transmit trigger frames to initiate and synchronize UL MU-OFDMA or UL MU-MIMO transmissions from multiple STAs 104 to AP 102. Such trigger frames thus enable multiple STAs 104 to concurrently send UL traffic to AP 102 in time. The trigger frame can address one or more STAs 104 via a corresponding Association Identifier (AID), and can assign one or more RUs to each AID (and thus to each STA 104), which can be used to send UL traffic to AP 102. The AP can also specify one or more Random Access (RA) RUs that are contentious for by unscheduled STAs 104.

[0064] Figure 4 A block diagram of an example wireless communication device 400 is shown. In some implementations, the wireless communication device 400 may be for STAs (such as those mentioned above). Figure 1Examples of devices in one of the STAs 104 described above. In some implementations, the wireless communication device 400 may be for an AP (such as those described above). Figure 1 Example of a device in the described AP 102. Wireless communication device 400 is capable of transmitting (or outputting for transmission) and receiving wireless communications (e.g., in the form of wireless packets). For example, the wireless communication device can be configured to transmit and receive packets in the form of Physical Layer Convergence Protocol (PLCP) Protocol Data Units (PPDUs) and Media Access Control (MAC) Protocol Data Units (MPDUs) conforming to IEEE 802.11 standards (such as those defined by the IEEE 802.11-2016 specification or its amendments, including but not limited to 802.11ah, 802.11ad, 802.11ay, 802.11ax, 802.11az, 802.11ba, and 802.11be).

[0065] The wireless communication device 400 may be or may include a chip, system-on-a-chip (SoC), chipset, package, or device that includes one or more modems 402 (e.g., a Wi-Fi (compliant with IEEE 802.11) modem). In some implementations, the one or more modems 402 (collectively, “Modem 402”) additionally include a WWAN modem (e.g., a 3GPP 4G LTE or 5G compatible modem). In some implementations, the wireless communication device 400 also includes one or more radios 404 (collectively, “Radio 404”). In some implementations, the wireless communication device 400 further includes one or more processors, processing blocks, or processing elements 406 (collectively, “Processor 406”) and one or more memory blocks or elements 408 (collectively, “Memory 408”).

[0066] Modem 402 may include intelligent hardware blocks or devices (e.g., application-specific integrated circuits (ASICs) and other possibilities). Modem 402 is generally configured to implement the PHY layer. For example, modem 402 is configured to modulate packets and output modulated packets to radio 404 for transmission over a wireless medium. Similarly, modem 402 is configured to acquire modulated packets received by radio 404 and demodulate these packets to provide demodulated packets. In addition to modulators and demodulators, modem 402 may further include digital signal processing (DSP) circuitry, automatic gain control (AGC), decoders, decoders, multiplexers, and demultiplexers. For example, when in transmission mode, data acquired from processor 406 is provided to a decoder, which encodes the data to provide encoded bits. The encoded bits are then mapped to points in a modulation constellation (using a selected MCS) to provide modulated symbols. Subsequently, the modulated symbols can be mapped to a number of... N SS A spatial flow or number N STS A space-time stream. The modulated symbols in the corresponding space stream or space-time stream can then be multiplexed, transformed via an inverse fast Fourier transform (IFFT) block, and subsequently provided to the DSP circuitry for Tx windowing and filtering. The digital signal can then be provided to a digital-to-analog converter (DAC). The resulting analog signal can then be provided to an up-converter and ultimately to radio 404. In beamforming implementations, the modulated symbols in the corresponding space stream are pre-coded via a guiding matrix before being provided to the IFFT block.

[0067] In receive mode, the digital signal received from radio 404 is provided to a DSP circuitry system configured to acquire the received signal, for example, by detecting the presence of the signal and estimating the initial timing and frequency offset. The DSP circuitry system is further configured to digitally condition the digital signal, for example, using channel (narrowband) filtering, analog impairment conditioning (such as correcting I / Q imbalance), and applying digital gain to ultimately obtain a narrowband signal. The output of the DSP circuitry system can then be fed to an AGC, configured to use information extracted from the digital signal (e.g., in one or more received training fields) to determine an appropriate gain. The output of the DSP circuitry system is also coupled to a demodulator configured to extract modulated symbols from the signal and, for example, calculate the log-likelihood ratio (LLR) for each bit position of each subcarrier in each spatial stream. The demodulator is coupled to a decoder configured to process the LLR to provide decoded bits. The decoded bits from all spatial streams are then fed to a demultiplexer for demultiplexing. The demultiplexed bits can then be descrambled and provided to the MAC layer (processor 406) for processing, evaluation, or interpretation.

[0068] Radio 404 generally includes at least one radio frequency (RF) transmitter (or “transmitter chain”) and at least one RF receiver (or “receiver chain”), which may be combined into one or more transceivers. For example, the RF transmitter and receiver may include various DSP circuitry systems, each including at least one power amplifier (PA) and at least one low-noise amplifier (LNA). The RF transmitter and receiver may further be coupled to one or more antennas. For example, in some implementations, wireless communication device 400 may include or be coupled to multiple transmit antennas (each with a corresponding transmit chain) and multiple receive antennas (each with a corresponding receive chain). Symbols output from modem 402 are provided to radio 404, which then transmits these symbols via the coupled antennas. Similarly, symbols received via the antennas are acquired by radio 404, which then provides these symbols to modem 402.

[0069] Processor 406 may include intelligent hardware blocks or devices designed to perform the functions described herein, such as, for example, processing cores, processing blocks, central processing units (CPUs), microprocessors, microcontrollers, digital signal processors (DSPs), application-specific integrated circuits (ASICs), programmable logic devices (PLDs) (such as field-programmable gate arrays (FPGAs)), discrete gate or transistor logic, discrete hardware components, or any combination thereof. Processor 406 processes information received via radio 404 and modem 402, and processes information to be output via modem 402 and radio 404 for transmission over a wireless medium. For example, processor 406 may implement a control plane and a MAC layer, configured to perform various operations related to the generation and transmission of MPDUs, frames, or packets. The MAC layer is configured to perform or facilitate frame decoding and decoding, spatial multiplexing, space-time block decoding (STBC), beamforming, and OFDMA resource allocation, and other operations or techniques. In some implementations, processor 406 may generally control modem 402 to cause the modem to perform the various operations described above.

[0070] Memory 408 may include tangible storage media, such as random access memory (RAM) or read-only memory (ROM), or combinations thereof. Memory 408 may also store non-transient processor or computer-executable software (SW) code containing instructions that, when executed by processor 406, cause the processor to perform various operations described herein for wireless communication, including the generation, transmission, reception, and interpretation of MPDUs, frames, or packets. For example, the various functions of the components disclosed herein, or the various blocks or steps of the methods, operations, processes, or algorithms disclosed herein, may be implemented as one or more modules of one or more computer programs.

[0071] Figure 5A A block diagram of an example AP 502 is shown. For example, AP 502 could be a reference... Figure 1 The described example implementation of AP 102. AP 502 includes a wireless communication device (WCD) 510. For example, the wireless communication device 510 may be a reference... Figure 4An example implementation of the described wireless communication device 400 is described. AP 502 also includes a plurality of antennas 520 coupled to the wireless communication device 510 for transmitting and receiving wireless communications. In some implementations, AP 502 additionally includes an application processor 530 coupled to the wireless communication device 510, and a memory 540 coupled to the application processor 530. AP 502 further includes at least one external network interface 550, which enables AP 502 to communicate with a core network or backhaul network to obtain access to external networks, including the Internet. For example, external network interface 550 may include one or both of a wired (e.g., Ethernet) network interface and a wireless network interface (such as a WWAN interface). Components of the foregoing can communicate directly or indirectly with other components of these components on at least one bus. AP 502 further includes a housing that encloses the wireless communication device 510, application processor 530, memory 540, and at least a portion of the antennas 520 and external network interface 550.

[0072] Figure 5B A block diagram of example STA 504 is shown. For example, STA 504 could be a reference... Figure 1 One or more example implementations of STA 104 are described. STA 504 includes wireless communication device 515. For example, wireless communication device 515 may be a reference... Figure 4 An example implementation of the described wireless communication device 400. STA 504 also includes one or more antennas 525 coupled to the wireless communication device 515 for transmitting and receiving wireless communications. STA 504 additionally includes an application processor 535 coupled to the wireless communication device 515, and a memory 545 coupled to the application processor 535. In some implementations, STA 504 further includes a user interface (UI) 555 (such as a touchscreen or keyboard) and a display 565, which can be integrated with the UI 555 to form a touchscreen display. In some implementations, STA 504 may further include one or more sensors 575 (for example, one or more inertial sensors, accelerometers, temperature sensors, pressure sensors, or altitude sensors). Components of the foregoing can communicate directly or indirectly with other components of these components on at least one bus. STA 504 further includes a housing (not shown for simplicity) that encloses the wireless communication device 515, the application processor 535, the memory 545, and at least a portion of the antenna 525, the UI 555, and the display 565.

[0073] Figure 6 A flowchart illustrating an example process 600 for supporting restricted TWT sessions, based on some implementation, is shown. Process 600 can be implemented by a wireless communication device (such as the one mentioned above). Figure 4 The described wireless communication device 400) performs the procedure. In some implementations, the procedure 600 can be performed by an AP (such as those described above, referred to separately). Figure 1 and Figure 5A The wireless communication device that operates or operates within the AP (either of the AP102 and 502 described) is used to perform this function.

[0074] In some implementations, process 600 begins at block 602, establishing a restricted target wake-up time (TWT) session over the radio medium for one or more radio stations (STAs) associated with time-sensitive traffic. This restricted TWT session includes one or more restricted TWT service periods (SPs) for communicating only with the one or more STAs associated with the time-sensitive traffic over the radio medium. At block 604, process 600 proceeds to the beginning of each of the one or more restricted TWT SPs, transmitting a clear transmit (CTS) frame over the radio medium. This CTS frame indicates to other STAs that the radio medium is busy or unavailable during the duration of the corresponding restricted TWT SP. At block 606, process 600 proceeds to, during at least one of the one or more restricted TWT SPs, transmitting or receiving time-sensitive data from the one or more STAs.

[0075] In some implementations, the Receiver Address (RA) of the CTS frame is set to a configured Media Access Control (MAC) address, indicating that the STA belonging to the restricted TWT session is permitted access to the radio medium during the corresponding restricted TWT SP. In some instances, the configured MAC address corresponds to a configured Network Assignment Vector (NAV) setting for other STAs.

[0076] Figure 7A A flowchart illustrating an example process 700 for supporting restricted TWT sessions, based on some implementation, is shown. Process 700 can be implemented by a wireless communication device (such as the one mentioned above). Figure 4 The described wireless communication device 400) performs the procedure. In some implementations, the procedure 700 can be performed by an AP (such as those described above, referred to separately). Figure 1 and Figure 5A The process 700 is performed by a wireless communication device that operates or operates within an AP (either of the described AP102 and 502). In some instances, process 700 can be performed by... Figure 6This is performed after a restricted TWT session is established in box 602. For example, in box 702, process 700 includes instructing each of the other STAs to terminate a Transmission Opportunity (TXOP) on the radio medium at or before the start of each of the one or more restricted TWT SPs. In some instances, this instruction may be included in a TWT element carried in one or more beacon frames transmitted from the AP. In some other instances, the instruction may be included in another field of the beacon frame, or may be included in another suitable management frame transmitted from the AP.

[0077] Figure 7B A flowchart illustrating an example process 710 for supporting restricted TWT sessions, based on some implementation, is shown. Process 710 can be implemented by a wireless communication device (such as the one mentioned above). Figure 4 The described wireless communication device 400) performs the procedure. In some implementations, the process 710 can be performed by an AP (such as those described above, referred to separately). Figure 1 and Figure 5A The process 710 is performed by a wireless communication device that operates or operates within an AP (either of the described AP102 and 502). In some instances, process 710 can be performed by... Figure 6 This is performed after a restricted TWT session is established in box 602. For example, in box 712, process 710 includes instructing each of the other STAs not to be permitted access to the radio medium during each of the one or more restricted TWT SPs. In some instances, this instruction may be included in a TWT element carried in one or more beacon frames transmitted from the AP. In some other instances, the instruction may be included in another field of the beacon frame, or may be included in another suitable management frame transmitted from the AP.

[0078] Figure 7C A flowchart illustrating an example process 720 for supporting restricted TWT sessions, based on some implementation, is shown. Process 720 can be implemented by a wireless communication device (such as the one mentioned above). Figure 4 The described wireless communication device 400) performs the procedure. In some implementations, the procedure 720 can be performed by an AP (such as those described above, referred to separately). Figure 1 and Figure 5A The process 720 is performed by a wireless communication device that operates or operates within an AP (either of the described AP102 and 502). In some instances, process 720 can be performed by... Figure 6 This is performed after transmitting or receiving time-delay sensitive data in box 606. For example, in box 722, process 720 includes granting access to the wireless medium to one or more other STAs during a time period outside of the one or more restricted TWT SPs of the restricted TWT session.

[0079] Figure 8 The diagram illustrates an example process 800 for supporting restricted TWT sessions via wireless communication, based on some implementation. Process 800 can be implemented by a wireless communication device (such as the one described above). Figure 4 The described wireless communication device 400) performs the procedure. In some implementations, the procedure 800 can be performed by an AP (such as those described above, referred to separately). Figure 1 and Figure 5A The process 800 is performed by a wireless communication device that operates or operates within an AP (either of the described AP102 and 502). In some instances, process 800 can be... Figure 6 The process is executed after a restricted TWT session is established in box 602. For example, in box 802, process 800 begins by detecting that no data transmission from the one or more STAs has occurred for more than a certain period during the corresponding restricted TWT SP. In box 804, process 800 proceeds to releasing control of the wireless medium for the remainder of the corresponding restricted TWT SP based on the detection that no data transmission from the one or more STAs has occurred. In some instances, the AP can release control of the wireless medium by transmitting a contention-free end (CF-END) frame on the wireless medium, which can signal the end of the corresponding restricted TWT SP.

[0080] Figure 9 The diagram illustrates a flowchart of an example process 900 for supporting wireless communication in a restricted TWT session, based on some implementation. Process 900 can be implemented by a wireless communication device (such as the one described above). Figure 4 The described wireless communication device 400) performs the procedure. In some implementations, the procedure 900 can be performed by an AP (such as those described above, referred to separately). Figure 1 and Figure 5A The process 900 is performed by a wireless communication device that operates or operates within an AP (either of the described AP102 and 502). In some instances, process 900 may be... Figure 6 One implementation of establishing a restricted TWT session is shown in box 602. For example, in box 902, process 900 begins by transmitting a frame indicating a delay-sensitive traffic priority associated with the restricted TWT session. In box 904, process 900 proceeds to receiving from each of the one or more STAs a request to become a member of the restricted TWT session based on the indicated delay-sensitive traffic priority.

[0081] In some implementations, the indicated latency-sensitive traffic priority may correspond to one or more selected traffic identifiers (TIDs). In some instances, the one or more selected TIDs may be associated with a Voice Access Class (AC_VO). In some other instances, the one or more selected TIDs may be associated with another access class. In some other implementations, the indicated latency-sensitive traffic priority may correspond to a selected traffic flow. In some instances, the selected traffic flow may be identified by an IP 5-tuple or an IPv6 flow label.

[0082] In some implementations, the frame can be one or more of a beacon frame, probe response frame, association frame, or reassociation frame. In some instances, the frame may include one or more TWT parameters associated with the restricted TWT session. These one or more TWT parameters may be included in the TWT parameter information field of a TWT element carried in one or more beacon frames transmitted by the AP. In some instances, these one or more TWT parameters may indicate whether the restricted TWT session is a peer-to-peer TWT session. In other instances, these one or more TWT parameters may indicate whether the restricted TWT session is full.

[0083] Figure 10 The diagram illustrates a flowchart of an example process 1000 for supporting wireless communication in a restricted TWT session, based on some implementation. Process 1000 can be implemented by a wireless communication device (such as the one described above). Figure 4 The described wireless communication device 400) performs the procedure. In some implementations, the procedure 1000 can be performed by an AP (such as those described above, referred to separately). Figure 1 and Figure 5A The process 1000 is performed by a wireless communication device that operates or operates within an AP (either of the described APs 102 and 502). In some instances, process 1000 can be... Figure 6 This is performed after a restricted TWT session is established in box 602. For example, in box 1002, process 1000 includes allowing the one or more STAs to transmit or receive traffic only corresponding to the one or more selected TIDs during each of the one or more restricted TWT SPs.

[0084] Figure 11 A flowchart illustrating an example process 1100 for supporting restricted TWT sessions via wireless communication, based on some implementation, is shown. Process 1100 can be implemented by a wireless communication device (such as the one described above). Figure 4 The described wireless communication device 400) performs this operation. In some implementations, process 1100 can be performed by an AP (such as those described above, referred to separately). Figure 1 and Figure 5AThe process 1100 is performed by a wireless communication device that operates or operates within an AP (one of the described APs 102 and 502). In some instances, process 1100 can be performed by... Figure 6 This is performed before or concurrently with establishing a restricted TWT session in box 602. For example, in box 1102, process 1100 begins by verifying that each of the one or more STAs is associated with the indicated latency-sensitive traffic priority. In box 1104, process 1100 proceeds to add the one or more STAs to the restricted TWT session based on the corresponding verification of the STAs.

[0085] Figure 12 A flowchart illustrating an example process 1200 for supporting restricted TWT sessions via wireless communication, based on some implementation, is shown. Process 1200 can be implemented by a wireless communication device (such as the one described above). Figure 4 The described wireless communication device 400) performs the procedure. In some implementations, the procedure 1200 can be performed by an AP (such as those described above, referred to separately). Figure 1 and Figure 5A The process 1200 is performed by a wireless communication device that operates or is within an AP (either of the described APs 102 and 502). In some instances, process 1200 may be... Figure 6 One implementation for establishing a restricted TWT session is shown in box 602. For example, in box 1202, process 1200 begins by determining the periodicity of delay-sensitive traffic associated with at least one of the one or more STAs. In box 1204, process 1200 proceeds to configuring the TWT wake-up interval based on the determined periodicity.

[0086] Figure 13A A timing diagram 1300A is shown illustrating communication transmissions supporting restricted TWT sessions according to some implementations. The communication shown in timing diagram 1300A is exchanged between an AP, two wireless stations STA1a and STA1b, and another wireless station STA2. Wireless stations STA1a and STA1b are associated with latency-sensitive traffic and are members of a TWT session established by the AP, while wireless station STA2 is not associated with latency-sensitive traffic and is not a member of a TWT session established by the AP. Therefore, stations STA1a and STA1b may be referred to herein as latency-sensitive STAs, while station STA2 may be referred to herein as a non-latency-sensitive STA. The AP may be one of the above-mentioned references. Figure 1 and 5A An example of the described AP 102 and AP 502. Each of the wireless stations STA1a, STA1b, and STA2 can be referred to in the above respective references. Figure 1 and 5B An example of STA 104 and 504 described.

[0087] For simplicity, only two stations, STA1a and STA1b, are shown as members of the restricted TWT session, and only one station, STA2, is shown as associated with the AP but not as a member of the restricted TWT session. In some other implementations, the restricted TWT session may include more than Figure 13A The examples depicted have fewer or more STAs.

[0088] Before time t0, the AP can establish a restricted TWT session for one or more STAs associated with delay-sensitive traffic. A restricted TWT session may include one or more restricted TWT service periods (SPs) for communicating over the radio medium only with STAs associated with the delay-sensitive traffic and who are members of that restricted TWT session. As discussed, each of stations STA1a and STA1b is associated with the delay-sensitive traffic and is a member of the restricted TWT session; station STA2 is not associated with the delay-sensitive traffic and is not a member of the restricted TWT session.

[0089] An AP can advertise restricted TWT sessions by including a TWT element in the beacon frame broadcast to its associated STA. The TWT element can indicate the existence of a restricted TWT session, indicate that the restricted TWT session is associated with time-sensitive traffic, and indicate one or more parameters of the restricted TWT session. For example, these parameters can indicate the duration of the restricted TWT SP, the duration of the restricted TWT wake-up interval, whether the restricted TWT session is a broadcast TWT session or an individual TWT session, whether the restricted TWT session is a peer-to-peer TWT session, the operating channel, the target wake-up time, and other TWT information.

[0090] In some implementations, the TWT element can indicate that a restricted TWT session is for an STA that has or is associated with delay-sensitive traffic corresponding to one or more selected Traffic Identifiers (TIDs). For example, in some instances, the selected TID can be associated with a Voice Access Class (AC_VO). In other implementations, the TWT element can indicate that a restricted TWT session is for an STA that has or is associated with delay-sensitive traffic corresponding to a configured tag or selected traffic flow. For example, in some instances, the configured tag or selected traffic flow can be identified by an IP 5-tuple or an IPv6 flow label. Stations STA1a and STA1b can receive the TWT element and can request the AP to add or join stations STA1a and STA1b to the restricted TWT session. In some instances, a request sent by stations STA1a and STA1b can indicate that the respective stations STA1a and STA1b have delay-sensitive traffic corresponding to the selected TID indicated in the TWT element. Before allowing stations STA1a and STA1b to join a restricted TWT session, the AP can verify that the TID associated with the corresponding traffic flow of stations STA1a and STA1b matches the selected TID indicated in the TWT element.

[0091] In some instances, the TWT element may also include an indication that causes another STA (such as STA2) to terminate its corresponding TXOP on the radio medium at or before the start of each restricted TWT SP in the restricted TWT session. For example, STA2 may receive one or more beacon frames broadcast from the AP, may decode the TWT element, and may terminate its UL data transmission at or before time t0 based on this indication. In some instances, the indication to terminate the TXOP may be carried in the TWT parameter information field of the TWT element.

[0092] At time t0, which corresponds to the start of the restricted TWT SP, stations STA1a and STA1b wake up, and the AP transmits a Clear Transmit (CTS) frame on the radio medium. The CTS frame can indicate to STA2 (and other STAs not part of the restricted TWT session) that the radio medium is unavailable during the duration of the restricted TWT SP. Station STA2 (and other STAs) receive the CTS frame and do not access the radio medium during the restricted TWT SP, for example, by setting their NAV to the time period corresponding to the duration of the restricted TWT SP. In some instances, the AP can set the Receiver Address (RA) of the CTS frame to a configured MAC address indicating a specific value, which STA2 and other non-participating STAs can set their respective NAVs to. Setting the RA of the CTS frame to a configured MAC address can also indicate that stations STA1a and STA1b (and other STAs already in the restricted TWT session) can ignore the CTS frame (and therefore will not set their NAVs).

[0093] As shown in the figure, STA1a transmits UL data to the AP over the radio medium at time t1, and STA1b transmits UL data to the AP over the radio medium at time t2. In some other implementations, stations STA1a and STA1b can use any suitable multi-user signaling technology (such as OFDMA or MU-MIMO) to concurrently transmit UL data to the AP.

[0094] At time t3, the restricted TWT SP ends, and station STA2 can access the radio medium. In some instances, STA2 can use a contention-based channel access mechanism (such as EDCA) to gain access to the radio medium. Figure 13A In the example, STA2 gains access to the wireless medium and transmits UL data to the AP at time t4. Time t5 can represent the end of the restricted TWT wake-up interval.

[0095] Figure 13B The timing diagram 1300B illustrates the communication transmission supporting restricted TWT sessions according to some other implementations. Figure 13B Timing diagram 1300B and Figure 13A The timing diagram is similar to that of 1300A, except that... Figure 13BIn the example, the AP detects no data transmission from stations STA1a and STA1b during the restricted TWT SP. Specifically, the AP can monitor the radio medium during the restricted TWT SP to look for UL transmissions from stations STA1a and STA1b. If the AP does not detect any UL transmissions from stations STA1a and STA1b for a period beyond the restricted TWT SP, the AP can release the radio medium. In some instances, the AP can release the radio medium by transmitting a contention-free end (CF-END) frame to terminate the restricted TWT SP. STA2 receives the CF-END frame, gains access to the radio medium, and transmits UL data to the AP at time t2. Time t3 indicates the scheduled end of the restricted TWT SP, and time t4 indicates the end of the restricted TWT wake-up interval.

[0096] Figure 14A An example structure of a TWT element 1400, according to some implementations, for use in supporting wireless communication for restricted TWT sessions is shown. The TWT element 1400 may include an element ID field 1402, a length field 1404, a control field 1406, and a TWT parameter information field 1408. The element ID field 1402 indicates that the element is a TWT element. The length field 1404 indicates the length of the TWT element 1400. The control field 1406 includes various control information for the restricted TWT session. The TWT parameter information field 1408 contains a single individual TWT parameter set field or one or more broadcast TWT parameter set fields.

[0097] Figure 14B An example structure of a broadcast TWT parameter set field 1410 for wireless communication that can be used to support restricted TWT sessions, according to some implementations, is shown. The broadcast TWT parameter set field 1410 may include a request type field 1412, a target wake-up time field 1414, a nominal minimum TWT wake-up duration field 1416, a TWT wake-up interval tail number field 1418, and a broadcast TWT information field 1419.

[0098] Figure 14C Example structures of a request type field 1420 for a broadcast TWT parameter set field used in wireless communication to support restricted TWT sessions are shown, according to some implementations. The request type field 1420 may include a TWT request field 1422, a TWT setup command field 1424, a trigger field 1426, a last broadcast parameter set field 1428, a stream type field 1430, a broadcast TWT recommendation field 1432, a TWT wake-up interval index field 1434, and several reserved bits 1436. In some implementations, the broadcast TWT recommendation field 1432 may indicate whether the restricted TWT session is a peer-to-peer TWT session or a broadcast TWT session.

[0099] Figure 15 A block diagram of an example wireless communication device 1500 according to some implementations is shown. In some implementations, the wireless communication device 1500 is configured to perform the above-mentioned references. Figure 6 , 7A One or more of the processes described in –7C, 8, 9, 10, 11, and 12. In some implementations, the wireless communication device 1500 may be one of the above references. Figure 4 An example implementation of the described wireless communication device 400. For example, the wireless communication device 1500 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).

[0100] Wireless communication device 1500 includes a receiving component 1510, a communication manager 1520, and a transmitting component 1530. The communication manager 1520 may further include a restricted TWT session component 1522, an early TWT SP termination component 1524, and a time-delay-sensitive traffic determination component 1526. A portion of one or more of components 1522, 1524, and 1526 may be implemented at least partially in hardware or firmware. In some implementations, at least one of components 1522, 1524, or 1526 is implemented at least partially as software stored in memory (such as memory 408). For example, a portion of one or more of components 1522, 1524, and 1526 may be implemented as non-transient instructions or code executable by a processor (such as processor 406) to perform the function or operation of the respective component.

[0101] Receiving component 1510 is configured to receive RX signals from other wireless communication devices. In some implementations, the RX signal may include UL data from one or more STAs (such as delay-sensitive STAs) belonging to a restricted TWT session, may include UL data from one or more other STAs (such as non-delay-sensitive STAs), and may include a request to join the restricted TWT session. In some implementations, restricted TWT session component 1522 establishes and schedules one or more restricted TWT sessions on the wireless medium. Early TWT SP termination component 1524 determines whether there is no data transmission from STAs belonging to the restricted TWT session for more than a certain period of the corresponding TWT SP. Delay-sensitive traffic determination component 1526 determines whether the traffic associated with the STA is delay-sensitive traffic, for example, whether the TID of the STA-based traffic flow matches one or more TIDs indicated in the TWT element. Transmitting component 1530 is configured to transmit TX signals to other wireless communication devices. In some implementations, the TX signal may include a beacon frame, a CTS frame, a CF-END frame, or a trigger frame.

[0102] Examples of implementations are described in the following numbered clauses.

[0103] 1. A wireless communication method performed by a wireless communication device operating as an access point (AP), comprising: Establish a restricted target wake-up time (TWT) session on a wireless medium for one or more radio stations (STAs) associated with time-delay-sensitive traffic. The restricted TWT session includes one or more restricted TWT service periods (SPs) for communicating only with the one or more STAs associated with time-delay-sensitive traffic on the wireless medium. At the beginning of each of the one or more restricted TWT SPs, a Clear Transmit (CTS) frame is transmitted on the radio medium, indicating to other STAs that the radio medium is unavailable for the duration of the corresponding restricted TWT SP; and During at least one of the one or more restricted TWT SPs, delay-sensitive data is transmitted to or received from the one or more STAs.

[0104] 2. The method of Clause 1, wherein the receiver address (RA) of the CTS frame is set to a configured media access control (MAC) address that indicates that the STA belonging to the restricted TWT session is permitted access to the radio medium during the corresponding restricted TWT SP.

[0105] 3. The method of Clause 2, wherein the configured MAC address corresponds to the configured network allocation vector (NAV) setting for the other STA.

[0106] 4. The methods of any or more of the provisions 1-3 further include: Instruct each of the other STAs to terminate the transmission opportunity (TXOP) on the wireless medium at or before the start of each of the one or more restricted TWT SPs.

[0107] 5. The methods of any or more of Clauses 1-4 further include: Instruct each of the other STAs not to be permitted access to the wireless medium during each of the one or more restricted TWT SPs.

[0108] 6. The method as described in Clause 4 or 5, wherein the indication is included in the TWT parameter information field of a TWT element carried in one or more beacon frames.

[0109] 7. The method of any or more of the provisions 1-6, wherein the other STA includes a non-delay-sensitive STA.

[0110] 8. The methods of any or more of Clauses 1-7 further include: During the time period outside of the one or more restricted TWT SPs of the restricted TWT session, one or more of the other STAs are permitted to access the wireless medium.

[0111] 9. The methods of any or more of Clauses 1-8 further include: The detection indicates that no data transmission from one or more STAs has occurred for more than a certain period during the corresponding restricted TWT SP; and Based on the detection that no data transmission is occurring from the one or more STAs, control over the wireless medium is released for the remainder of the corresponding restricted TWT SP.

[0112] 10. The method of Clause 9, wherein releasing control of the wireless medium includes transmitting a contention-free end (CF-END) frame on the wireless medium.

[0113] 11. The methods described in Clause 9 or 10 further include: During the remainder of the corresponding restricted TWT SP, uplink (UL) data is received from one or more of the other STAs.

[0114] 12. The method of any or more of Clauses 1-11, wherein establishing a restricted TWT session includes: Transmit frames indicating the time-sensitive traffic priority associated with the restricted TWT session; and Receive requests from each of the one or more STAs to become a member of the restricted TWT session based on the indicated delay-sensitive traffic priority.

[0115] 13. The method of Clause 12, wherein the indicated delay-sensitive traffic priority corresponds to one or more selected traffic identifiers (TIDs).

[0116] 14. The method of Clause 13, wherein the one or more selected TIDs are associated with a voice access class (AC_VO).

[0117] 15. The method of any or more of the provisions 13-14, wherein the one or more selected TIDs correspond to the configured tags.

[0118] 16. The method of any or more of Clauses 12-15, wherein the indicated delay-sensitive traffic priority corresponds to the selected traffic flow.

[0119] 17. The method of Clause 16, wherein the selected traffic flow is identified by an IP 5-tuple or an IPv6 flow label.

[0120] 18. The methods of any or more of Clauses 12-17, further comprising: During each of the one or more restricted TWT SPs, the one or more STAs are permitted to transmit or receive traffic that corresponds only to the one or more selected TIDs.

[0121] 19. The methods of any or more of Clauses 12-18, further comprising: Verify that each of the one or more STAs is associated with the indicated delay-sensitive traffic priority; and Add one or more STAs to the restricted TWT session based on the appropriate authentication of the STA.

[0122] 20. The method of any or more of Clauses 12-19, wherein the frame includes one or more of a beacon frame, a probe response frame, an association frame, or a reassociation frame.

[0123] 21. The method of Clause 12, wherein the frame includes one or more TWT parameters associated with the restricted TWT session.

[0124] 22. The method of Clause 21, wherein the one or more TWT parameters are included in the TWT parameter information field of the TWT element carried in one or more beacon frames.

[0125] 23. The method as described in Clause 21 or 22, wherein the one or more TWT parameters indicate whether the restricted TWT session is a peer-to-peer TWT session.

[0126] 24. The method of Clause 21, wherein the one or more TWT parameters indicate whether the restricted TWT session is filled.

[0127] 25. The method of any or more of clauses 1-24, wherein establishing a restricted TWT session includes: Determine the periodicity of delay-sensitive traffic associated with at least one of the one or more STAs; and Configure the TWT interval based on the determined periodicity.

[0128] 26. A wireless communication device, comprising: At least one modem; At least one processor, the at least one processor being communicatively coupled to the at least one modem; and At least one memory, communicatively coupled to and storing processor-readable code, which is configured to, when executed by the at least one processor in conjunction with the at least one modem: Establish a restricted target wake-up time (TWT) session on a wireless medium for one or more radio stations (STAs) associated with time-delay-sensitive traffic. The restricted TWT session includes one or more restricted TWT service periods (SPs) for communicating only with the one or more STAs associated with time-delay-sensitive traffic on the wireless medium. At the beginning of each of the one or more restricted TWT SPs, a Clear Transmit (CTS) frame is transmitted on the radio medium, indicating to other STAs that the radio medium is unavailable for the duration of the corresponding restricted TWT SP; and During at least one of the one or more restricted TWT SPs, delay-sensitive data is transmitted to or received from the one or more STAs.

[0129] 27. A wireless communication device as described in Clause 26, wherein the receiver address (RA) of the CTS frame is set to a configured media access control (MAC) address that indicates that a STA belonging to the restricted TWT session is permitted access to the wireless medium during the corresponding restricted TWT SP.

[0130] 28. A wireless communication device as described in Clause 27, wherein the configured MAC address corresponds to a configured network allocation vector (NAV) setting for the other STA.

[0131] 29. A wireless communication device of any or more of the terms 26-28, wherein the execution of the processor-readable code is further configured to: Instruct each of the other STAs to terminate the transmission opportunity (TXOP) on the wireless medium at or before the start of each of the one or more restricted TWT SPs.

[0132] 30. A wireless communication device of any or more of the terms 26-29, wherein the execution of the processor-readable code is further configured to: Instruct each of the other STAs not to be permitted access to the wireless medium during each of the one or more restricted TWT SPs.

[0133] 31. Wireless communication devices as described in Clause 29 or 30, wherein the indication is included in the TWT parameter information field of a TWT element carried in one or more beacon frames.

[0134] 32. Wireless communication equipment of any or more of the terms 26-31, wherein the other STA includes a non-delay-sensitive STA.

[0135] 33. A wireless communication device of any or more of the terms 26-32, wherein the execution of the processor-readable code is further configured to: During the time period outside of the one or more restricted TWT SPs of the restricted TWT session, one or more of the other STAs are permitted to access the wireless medium.

[0136] 34. A wireless communication device of any or more of the terms 26-33, wherein the execution of the processor-readable code is further configured to: The detection indicates that no data transmission from one or more STAs has occurred for more than a certain period during the corresponding restricted TWT SP; and Based on the detection that no data transmission is occurring from the one or more STAs, control over the wireless medium is released for the remainder of the corresponding restricted TWT SP.

[0137] 35. A wireless communication device as described in Clause 34, wherein releasing control over the wireless medium includes transmitting a contention-free end (CF-END) frame on the wireless medium.

[0138] 36. A wireless communication device as described in Clause 34 or 35, wherein the execution of the processor-readable code is further configured to: During the remainder of the corresponding restricted TWT SP, uplink (UL) data is received from one or more of the other STAs.

[0139] 37. Wireless communication devices of any or more of the terms 26-36, wherein establishing a restricted TWT session includes: Transmit frames indicating the time-sensitive traffic priority associated with the restricted TWT session; and Receive requests from each of the one or more STAs to become a member of the restricted TWT session based on the indicated delay-sensitive traffic priority.

[0140] 38. Wireless communication equipment as described in Clause 37, wherein the indicated delay-sensitive traffic priority corresponds to one or more selected traffic identifiers (TIDs).

[0141] 39. Wireless communication devices as described in Clause 38, wherein the one or more selected TIDs are associated with a voice access class (AC_VO).

[0142] 40. Wireless communication devices as described in Clause 38 or 39, wherein the one or more selected TIDs correspond to a configured tag.

[0143] 41. Wireless communication equipment as described in Clause 37, wherein the indicated delay-sensitive traffic priority corresponds to the selected traffic flow.

[0144] 42. Wireless communication equipment as described in Clause 41, wherein the selected traffic flow is identified by an IP 5-tuple or an IPv6 flow tag.

[0145] 43. A wireless communication device of any or more of the terms 38-42, wherein the execution of the processor-readable code is further configured to: During each of the one or more restricted TWT SPs, the one or more STAs are permitted to transmit or receive traffic that corresponds only to the one or more selected TIDs.

[0146] 44. A wireless communication device of any or more of the provisions of 37-43, wherein the execution of the processor-readable code is further configured to: Verify that each of the one or more STAs is associated with the indicated delay-sensitive traffic priority; and Add one or more STAs to the restricted TWT session based on the appropriate authentication of the STA.

[0147] 45. A wireless communication device of any or more of the terms 37-44, wherein the frame includes one or more of a beacon frame, a probe response frame, an association frame, or a reassociation frame.

[0148] 46. ​​A wireless communication device of any or more of the terms 37-45, wherein the frame includes one or more TWT parameters associated with the restricted TWT session.

[0149] 47. A wireless communication device as described in Clause 46, wherein the one or more TWT parameters are included in the TWT parameter information field of a TWT element carried in one or more beacon frames.

[0150] 48. The wireless communication device of claim 46 or 47, wherein the one or more TWT parameters indicate whether the restricted TWT session is a peer-to-peer TWT session.

[0151] 49. A wireless communication device of any or more of the terms 46-48, wherein the one or more TWT parameters indicate whether a restricted TWT session is filled.

[0152] 50. Wireless communication devices of any or more of the terms 26-49, wherein establishing a restricted TWT session includes: Determine the periodicity of delay-sensitive traffic associated with at least one of the one or more STAs; and Configure the TWT interval based on the determined periodicity.

[0153] As used herein, the phrase “at least one of” or “one or more of” referring to a list of items means any combination of these items, including a single member. For example, “at least one of a, b, or c” is intended to cover the following possibilities: only a, only b, only c, 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.

[0154] The various illustrative components, logic, logic blocks, modules, circuits, operations, and algorithmic processes described in conjunction with the implementations disclosed herein can be implemented as electronic hardware, firmware, software, or a combination of hardware, firmware, or software, including the structures disclosed in this specification and their structural equivalents. This interchangeability of hardware, firmware, and software has been generally described in terms of its functionality and is illustrated in the various illustrative components, blocks, modules, circuits, and processes described above. Whether such functionality is implemented in hardware, firmware, or software depends on the specific application and the design constraints imposed on the overall system.

[0155] Various modifications to the implementations described in this disclosure may be 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 this disclosure. Therefore, the claims are not intended to be limited to the implementations shown herein, but are to be granted the broadest scope consistent with this disclosure, the principles disclosed herein, and the novel features.

[0156] Furthermore, the various features described in this specification in the context of separate implementations may also be implemented in combination in a single implementation. Conversely, the various features described in the context of a single implementation may also be implemented separately or in any suitable sub-combination in multiple implementations. Thus, although features may be described above as operating in a particular combination and even initially claimed in this way, one or more features from the claimed combination may be removed from that combination in some cases, and the claimed combination may be for sub-combinations or variations thereof.

[0157] Similarly, although the operations are depicted in a specific order in the accompanying drawings, this should not be construed as requiring such operations to be performed in the specific order shown or sequentially, or requiring the execution of all explained operations to achieve the desired result. Furthermore, the drawings may schematically depict one or more example processes in the form of flowcharts or flow diagrams. However, other operations not depicted may be incorporated into the schematically explained example processes. For example, one or more additional operations may be performed before, after, simultaneously with, or between any explained operations. In some environments, multitasking and parallel processing may be advantageous. Moreover, the separation of the various system components in the implementation described above should not be construed as requiring such separation in all implementations, and it should be understood that the described program components and systems can generally be integrated together in a single software product or packaged into multiple software products.

Claims

1. A wireless communication device, comprising: One or more memories, wherein the one or more memories store processor-readable code; as well as One or more processors, the one or more processors being communicatively coupled to the one or more memories, and configured to cause the wireless communication device to: when executing processor-readable code. A transmission management frame is provided, the management frame including a target wake-up time (TWT) element, wherein the TWT element includes a TWT parameter set field, the TWT parameter set field including one or more TWT parameters associated with a restricted TWT schedule, and wherein the one or more TWT parameters indicate that the restricted TWT schedule includes one or more restricted TWT service periods (SPs), and indicate one or more traffic identifiers (TIDs) corresponding to data traffic associated with the restricted TWT schedule; as well as Data is transmitted within at least one of the one or more restricted TWT SPs according to the one or more TIDs, wherein each STA in a group of STAs will terminate its respective transmission opportunity at or before the start of each of the one or more restricted TWT SPs according to the one or more TWT parameters.

2. The wireless communication device of claim 1, wherein one or more TIDs correspond to time-delay sensitive traffic.

3. The wireless communication device of claim 2, wherein the one or more TWT parameters indicate that the one or more restricted TWT SPs are available for the time-sensitive traffic and are not available for non-time-sensitive traffic.

4. The wireless communication device of claim 1, wherein the one or more TWT parameters indicate whether the restricted TWT schedule is full.

5. The wireless communication device of claim 1, wherein the one or more processors are configured to, when executing processor-readable code, cause the wireless communication device to: The system receives a request from an STA to become a member of the restricted TWT scheduler, wherein the request indicates that the STA has data traffic corresponding to the one or more TIDs indicated by the one or more TWT parameters.

6. The wireless communication device of claim 5, wherein the one or more processors are configured to, when executing processor-readable code, cause the wireless communication device to: Before allowing the STA to join the restricted TWT schedule, verify that the STA's data traffic corresponds to the one or more TIDs indicated by the one or more TWT parameters.

7. The wireless communication device of claim 1, wherein the restricted TWT scheduling is established via a scheduling STA associated with one or more restricted TWTs, and the wireless communication device transmits the management frame containing the TWT element.

8. The wireless communication device of claim 1, wherein the one or more processors are configured to, when executing processor-readable code, cause the wireless communication device to: Within one or more restricted TWT SPs, a contention-free end CF-END frame is transmitted, which terminates the restricted TWT SP before its scheduled end.

9. The wireless communication device of claim 8, wherein the one or more processors are configured to, when executing processor-readable code, cause the wireless communication device to: Within the restricted TWT SP, if no data transmission from one or more restricted TWTs via a scheduled STA is detected for more than a certain period of time, the CF-END frame is transmitted based on the detection that no data transmission from the one or more restricted TWTs via a scheduled STA is detected.

10. The wireless communication device as claimed in claim 1, wherein: The one or more TWT parameters indicate that each STA in the group will terminate its respective transmission opportunity at or before the start of each of the one or more restricted TWT SPs; or The one or more TIDs correspond to prioritized latency-sensitive traffic.

11. A wireless communication device, comprising: One or more memories, wherein the one or more memories store processor-readable code; as well as One or more processors, the one or more processors being communicatively coupled to the one or more memories, and configured to cause the wireless communication device to: when executing processor-readable code. Receive a management frame, the management frame including a target wake-up time (TWT) element, wherein the TWT element includes a TWT parameter set field, the TWT parameter set field includes one or more TWT parameters associated with a restricted TWT schedule, and wherein the one or more TWT parameters indicate that the restricted TWT schedule includes one or more restricted TWT service periods (SPs), and indicate one or more traffic identifiers (TIDs) corresponding to data traffic associated with the restricted TWT schedule; as well as Data is transmitted within at least one of the one or more restricted TWT SPs according to the one or more TIDs, wherein the wireless communication device terminates the transmission opportunity at or before the start of each of the one or more restricted TWT SPs according to the one or more TWT parameters.

12. The wireless communication device of claim 11, wherein one or more TIDs correspond to time-delay-sensitive traffic.

13. The wireless communication device of claim 12, wherein the one or more TWT parameters indicate that the one or more restricted TWT SPs are available for the time-sensitive traffic and are not available for non-time-sensitive traffic.

14. The wireless communication device of claim 11, wherein one or more TWT parameters indicate whether the restricted TWT schedule is full.

15. The wireless communication device of claim 11, wherein the one or more processors are configured to, when executing processor-readable code, cause the wireless communication device to: A request is transmitted to become a member of the restricted TWT scheduler, wherein the request indicates that the wireless communication device has data traffic corresponding to the one or more TIDs indicated by the one or more TWT parameters.

16. The wireless communication device of claim 11, wherein the one or more processors are configured to, when executing processor-readable code, cause the wireless communication device to: A trigger frame is received within one or more restricted TWT SPs, wherein the data is communicated based on the received trigger frame.

17. A wireless communication method performed by a wireless communication device, comprising: Receive a management frame, the management frame including a target wake-up time (TWT) element, wherein the TWT element includes a TWT parameter set field, the TWT parameter set field includes one or more TWT parameters associated with a restricted TWT schedule, and wherein the one or more TWT parameters indicate that the restricted TWT schedule includes one or more restricted TWT service periods (SPs), and indicate one or more traffic identifiers (TIDs) corresponding to data traffic associated with the restricted TWT schedule; as well as Data is transmitted within at least one of the one or more restricted TWT SPs according to the one or more TIDs, wherein the wireless communication device terminates the transmission opportunity at or before the start of each of the one or more restricted TWT SPs according to the one or more TWT parameters.

18. The method of claim 17, wherein the one or more TIDs correspond to time-delay sensitive traffic.

19. The method of claim 18, wherein the one or more TWT parameters indicate that the one or more restricted TWT SPs are available for the delay-sensitive traffic and are not available for non-delay-sensitive traffic.

20. The method of claim 17, wherein the one or more TWT parameters indicate whether the restricted TWT schedule is full.

Images