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WO2025059971A1 - Techniques de service à faible latence pour transmission de paquets - Google Patents

Techniques de service à faible latence pour transmission de paquets Download PDF

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Publication number
WO2025059971A1
WO2025059971A1 PCT/CN2023/120312 CN2023120312W WO2025059971A1 WO 2025059971 A1 WO2025059971 A1 WO 2025059971A1 CN 2023120312 W CN2023120312 W CN 2023120312W WO 2025059971 A1 WO2025059971 A1 WO 2025059971A1
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WO
WIPO (PCT)
Prior art keywords
data
sta
frame
indication
latency
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Application number
PCT/CN2023/120312
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English (en)
Inventor
Xin Wu
Linghui Wu
Junqi MIAO
Daqing Li
Yusheng Yang
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Qualcomm Inc
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Qualcomm Inc
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Publication date
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Priority to PCT/CN2023/120312 priority Critical patent/WO2025059971A1/fr
Publication of WO2025059971A1 publication Critical patent/WO2025059971A1/fr
Pending legal-status Critical Current
Anticipated expiration legal-status Critical

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W74/00—Wireless channel access
    • H04W74/04—Scheduled access
    • H04W74/06—Scheduled access using polling
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W72/00—Local resource management
    • H04W72/50—Allocation or scheduling criteria for wireless resources
    • H04W72/54—Allocation or scheduling criteria for wireless resources based on quality criteria
    • H04W72/543—Allocation or scheduling criteria for wireless resources based on quality criteria based on requested quality, e.g. QoS
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W72/00—Local resource management
    • H04W72/50—Allocation or scheduling criteria for wireless resources
    • H04W72/51—Allocation or scheduling criteria for wireless resources based on terminal or device properties
    • H04W72/512—Allocation or scheduling criteria for wireless resources based on terminal or device properties for low-latency requirements, e.g. URLLC

Definitions

  • This disclosure relates generally to wireless communication, and more specifically, to employing low-latency service techniques to support bounded low-latency service for event-based upstream packet transmission.
  • the processing system includes processor circuitry and memory circuitry that stores code and is coupled with the processor circuitry.
  • the processing system is configured to cause the wireless STA to transmit, to a wireless access point (AP) , a first frame including an indication that the STA has data to transmit, an indication of a size associated with the data, and an indication of a transmission time associated with transmitting the data in accordance with a latency constraint.
  • the processing system is configured to cause the wireless STA to receive, from the AP prior to the transmission time, and in association with transmission of the first frame, a trigger frame that includes a resource allocation identifying one or more resource units associated with the size for transmitting the data.
  • the processing system is configured to cause the wireless STA to transmit, to the AP in accordance with the transmission time and via the one or more resource units, a data frame that includes the data.
  • the AP includes a processing system that has one or more processors and one or more memories coupled with the one or more processors.
  • the processing system is configured to cause the AP to receive, from an STA, a first frame including an indication that the STA has data to transmit.
  • the indication includes a size of the data and an expected transmission time of the data.
  • the processing system is configured to cause the AP to transmit, to the STA, prior to the expected transmission time, a trigger frame that includes one or more resource units allocated to the data.
  • the processing system is configured to cause the AP to receive, from the STA via the one or more resource units, a data frame that includes the data.
  • the processing system is further configured to transmit to the STA, prior to receiving the first frame, a second trigger frame including a resource allocation for the first frame.
  • the method includes transmitting, to a wireless access point (AP) , a first frame including an indication that the STA has data to transmit, an indication of a size associated with the data, and an indication of a transmission time associated with transmitting the data in accordance with a latency constraint.
  • the method includes receiving, from the AP prior to the transmission time, and in association with transmission of the first frame, a trigger frame that includes a resource allocation identifying one or more resource units associated with the size for transmitting the data.
  • the method includes transmitting, to the AP in accordance with the transmission time and via the one or more resource units, a data frame that includes the data.
  • the method includes transmitting to the STA, prior to receiving the first frame, a second trigger frame including a resource allocation for the first frame.
  • FIG. 2 shows an example physical layer (PHY) protocol data unit (PPDU) usable for communications between a wireless access point (AP) and one or more wireless stations (STAs) .
  • PHY physical layer
  • PPDU protocol data unit
  • Figure 3 shows a hierarchical format of an example PPDU usable for communications between a wireless AP and one or more wireless STAs.
  • Figure 8 shows a flowchart illustrating an example process performable by an STA to provide information to an AP about a low-latency packet prior to the transmission of the low-latency packet.
  • Figure 13 shows an example pre-request information element usable to provide an AP information about an upcoming low-latency MSDU.
  • CDMA code division multiple access
  • TDMA time division multiple access
  • FDMA frequency division multiple access
  • OFDMA orthogonal FDMA
  • SC-FDMA single-carrier FDMA
  • SDMA spatial division multiple access
  • RSMA rate-splitting multiple access
  • MUSA multi-user shared access
  • SU single-user
  • MIMO multiple-input multiple-output
  • MU multi-user
  • the described examples also can be implemented using other wireless communication protocols or RF signals suitable for use in one or more of a wireless personal area network (WPAN) , a wireless local area network (WLAN) , a wireless wide area network (WWAN) , a wireless metropolitan area network (WMAN) , or an internet of things (IOT) network.
  • WPAN wireless personal area network
  • WLAN wireless local area network
  • WWAN wireless wide area network
  • WMAN wireless metropolitan area network
  • IOT internet of things
  • Various aspects relate generally to wireless communication and, more particularly, to low-latency services for packet transmission. Some aspects particularly relate to low-latency service techniques that support large-size event-based packet transmission from a station (STA) to an access point (AP) .
  • STA station
  • AP access point
  • an STA may have a large packet that has low-latency Quality of Service (QoS) requirements.
  • QoS Quality of Service
  • the STA can transmit an indication to the AP prior to an estimated time associated with a latency constraint of the packet.
  • the STA may transmit the indication using a resource unit pre-reserved by the AP for such indications.
  • the AP may periodically, asynchronously or simultaneously transmit to the STA trigger frames, each allocating one or more resource units (RUs) for the STA to provide the indication.
  • the STA can include the estimated size associated with the packet as well as the estimated time associated with the latency constraint.
  • the AP can determine an appropriate RU in accordance with the size of the packet provided in the indication.
  • the AP can then transmit a trigger frame to the STA that includes a resource allocation allocating the RU to the STA.
  • the AP transmits the trigger frame to the STA within a time window associated with the latency constraint to provide the STA with the appropriate resources required to transmit the packet in accordance with the latency constraint.
  • the present disclosure aims to maintain efficient communication across a network by implementing mechanisms ensuring that low-latency, large-size, event-based packets are transmitted in accordance with their respective low-latency QOS requirements.
  • the disclosure describes mechanisms involving the transmission of an indication regarding a low-latency, large-size, event-based packet to an AP prior to the expected transmission time of the packet.
  • the AP can allocate a resource unit appropriately sized for the packet prior to the expected transmission time of the packet.
  • the indication aids the AP in allocating resource units to the STA, ensuring the packet is transmitted in accordance with its low-latency QOS requirement. Increased reliability and efficiency in resource unit allocation is achieved by transmitting to the AP an indication regarding the packet before the estimated transmission time of the packet.
  • FIG. 1 shows a pictorial diagram of an example wireless communication network 100.
  • the wireless communication network 100 can be an example of a wireless local area network (WLAN) such as a Wi-Fi network.
  • WLAN wireless local area network
  • the wireless communication network 100 can be a network implementing at least one of the IEEE 802.11 family of wireless communication protocol standards (such as defined by the IEEE 802.11-2020 specification or amendments thereof including, but not limited to, 802.11ay, 802.11ax, 802.11az, 802.11ba, 802.11bd, 802.11be, 802.11bf, and 802.11bn) .
  • the wireless communication network 100 can be an example of a cellular radio access network (RAN) , such as a 5G or 6G RAN that implements one or more cellular protocols such as those specified in one or more 3GPP standards.
  • the wireless communication network 100 can include a WLAN that functions in an interoperable or converged manner with one or more cellular RANs to provide greater or enhanced network coverage to wireless communication devices within the wireless communication network 100 or to enable such devices to connect to a cellular network’s core, such as to access the network management capabilities and functionality offered by the cellular network core.
  • the wireless communication network 100 may include numerous wireless communication devices including at least one wireless access point (AP) 102 and any number of wireless stations (STAs) 104. While only one AP 102 is shown in Figure 1, the wireless communication network 100 can include multiple APs 102.
  • the AP 102 can be or represent various different types of network entities including, but not limited to, a home networking AP, an enterprise-level AP, a single-frequency AP, a dual-band simultaneous (DBS) AP, a tri-band simultaneous (TBS) AP, a standalone AP, a non-standalone AP, a software-enabled AP (soft AP) , and a multi-link AP (also referred to as an AP multi-link device (MLD) ) , as well as cellular (such as 3GPP, 4G LTE, 5G or 6G) base stations or other cellular network nodes such as a Node B, an evolved Node B (eNB) , a gNB,
  • Each of the STAs 104 also may be referred to as a mobile station (MS) , a mobile device, a mobile handset, a wireless handset, an access terminal (AT) , a user equipment (UE) , a subscriber station (SS) , or a subscriber unit, among other examples.
  • MS mobile station
  • AT access terminal
  • UE user equipment
  • SS subscriber station
  • subscriber unit a subscriber unit
  • the STAs 104 may represent various devices such as mobile phones, other handheld or wearable communication devices, netbooks, notebook computers, tablet computers, laptops, Chromebooks, augmented reality (AR) , virtual reality (VR) , mixed reality (MR) or extended reality (XR) wireless headsets or other peripheral devices, wireless earbuds, other wearable devices, display devices (for example, TVs, computer monitors or video gaming consoles) , video game controllers, navigation systems, music or other audio or stereo devices, remote control devices, printers, kitchen appliances (including smart refrigerators) or other household appliances, key fobs (for example, for passive keyless entry and start (PKES) systems) , Internet of Things (IoT) devices, and vehicles, among other examples.
  • augmented reality AR
  • VR virtual reality
  • MR mixed reality
  • XR extended reality
  • display devices for example, TVs, computer monitors or video gaming consoles
  • navigation systems music or other audio or stereo devices
  • remote control devices printers
  • kitchen appliances including smart refrigerators
  • key fobs
  • a single AP 102 and an associated set of STAs 104 may be referred to as a basic service set (BSS) , which is managed by the respective AP 102.
  • BSS basic service set
  • Figure 1 additionally shows an example coverage area 108 of the AP 102, which may represent a basic service area (BSA) of the wireless communication network 100.
  • the BSS may be identified by STAs 104 and other devices by a service set identifier (SSID) , as well as a basic service set identifier (BSSID) , which may be a medium access control (MAC) address of the AP 102.
  • SSID service set identifier
  • BSSID basic service set identifier
  • MAC medium access control
  • the AP 102 may periodically broadcast beacon frames ( “beacons” ) including the BSSID to enable any STAs 104 within wireless range of the AP 102 to “associate” or re-associate with the AP 102 to establish a respective communication link 106 (hereinafter also referred to as a “Wi-Fi link” ) , or to maintain a communication link 106, with the AP 102.
  • the beacons can include an identification or indication of a primary channel used by the respective AP 102 as well as a timing synchronization function (TSF) for establishing or maintaining timing synchronization with the AP 102.
  • TSF timing synchronization function
  • the AP 102 may provide access to external networks to various STAs 104 in the wireless communication network 100 via respective communication links 106.
  • each of the STAs 104 is configured to perform passive or active scanning operations ( “scans” ) on frequency channels in one or more frequency bands (for example, the 2.4 GHz, 5 GHz, 6 GHz, 45 GHz, or 60 GHz bands) .
  • scans passive or active scanning operations
  • an STA 104 listens for beacons, which are transmitted by respective APs 102 at periodic time intervals referred to as target beacon transmission times (TBTTs) .
  • TBTTs target beacon transmission times
  • an STA 104 generates and sequentially transmits probe requests on each channel to be scanned and listens for probe responses from APs 102.
  • Each STA 104 may identify, determine, ascertain, or select an AP 102 with which to associate in accordance with the scanning information obtained through the passive or active scans, and to perform authentication and association operations to establish a communication link 106 with the selected AP 102.
  • the selected AP 102 assigns an association identifier (AID) to the STA 104 at the culmination of the association operations, which the AP 102 uses to track the STA 104.
  • AID association identifier
  • an STA 104 may have the opportunity to select one of many BSSs within range of the STA 104 or to select among multiple APs 102 that together form an extended service set (ESS) including multiple connected BSSs.
  • the wireless communication network 100 may be connected to a wired or wireless distribution system that may enable multiple APs 102 to be connected in such an ESS.
  • an STA 104 can be covered by more than one AP 102 and can associate with different APs 102 at different times for different transmissions.
  • an STA 104 after association with an AP 102, an STA 104 also may periodically scan its surroundings to find a more suitable AP 102 with which to associate. For example, an STA 104 that is moving relative to its associated AP 102 may perform a “roaming” scan to find another AP 102 having more desirable network characteristics such as a greater received signal strength indicator (RSSI) or a reduced traffic load.
  • RSSI received signal strength indicator
  • STAs 104 may form networks without APs 102 or other equipment other than the STAs 104 themselves.
  • a network is an ad hoc network (or wireless ad hoc network) .
  • Ad hoc networks may alternatively be referred to as mesh networks or peer-to-peer (P2P) networks.
  • P2P peer-to-peer
  • ad hoc networks may be implemented within a larger network such as the wireless communication network 100.
  • the STAs 104 may be capable of communicating with each other through the AP 102 using communication links 106, STAs 104 also can communicate directly with each other via direct wireless communication links 110.
  • two STAs 104 may communicate via a direct communication link 110 regardless of whether both STAs 104 are associated with and served by the same AP 102.
  • one or more of the STAs 104 may assume the role filled by the AP 102 in a BSS.
  • Such an STA 104 may be referred to as a group owner (GO) and may coordinate transmissions within the ad hoc network.
  • Examples of direct wireless communication links 110 include Wi-Fi Direct connections, connections established by using a Wi-Fi Tunneled Direct Link Setup (TDLS) link, and other P2P group connections.
  • TDLS Wi-Fi Tunneled Direct Link Setup
  • the AP 102 or the STAs 104 may support applications associated with high throughput or low-latency requirements, or may provide lossless audio to one or more other devices.
  • the AP 102 or the STAs 104 may support applications and use cases associated with ultra-low-latency (ULL) , such as ULL gaming, or streaming lossless audio and video to one or more personal audio devices (such as peripheral devices) or AR/VR/MR/XR headset devices.
  • ULL ultra-low-latency
  • the AP 102 or the STAs 104 may support an extended personal audio network enabling communication with the two or more peripheral devices.
  • the AP 102 and STAs 104 may support additional ULL applications such as cloud-based applications (such as VR cloud gaming) that have ULL and high throughput requirements.
  • the AP 102 and the STAs 104 may function and communicate (via the respective communication links 106) according to one or more of the IEEE 802.11 family of wireless communication protocol standards. These standards define the WLAN radio and baseband protocols for the physical (PHY) and MAC layers.
  • the AP 102 and STAs 104 transmit and receive wireless communications (hereinafter also referred to as “Wi-Fi communications” or “wireless packets” ) to and from one another in the form of PHY protocol data units (PPDUs) .
  • Wi-Fi communications wireless packets
  • Each PPDU is a composite structure that includes a PHY preamble and a payload that is in the form of a PHY service data unit (PSDU) .
  • the information provided in the preamble may be used by a receiving device to decode the subsequent data in the PSDU.
  • the preamble fields may be duplicated and transmitted in each of 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 may be used for packet detection, automatic gain control and channel estimation, among other uses.
  • the legacy preamble also may generally be used to maintain compatibility with legacy devices.
  • the format of, coding of, and information provided in the non-legacy portion of the preamble is associated with the particular IEEE 802.11 wireless communication protocol to be used to transmit the payload.
  • the APs 102 and STAs 104 in the WLAN 100 may transmit PPDUs over an unlicensed spectrum, which may be a portion of spectrum that includes frequency bands traditionally used by Wi-Fi technology, such as the 2.4 GHz, 5 GHz, 6 GHz, 45 GHz, and 60 GHz bands.
  • Some examples of the APs 102 and STAs 104 described herein also may communicate in other frequency bands that may support licensed or unlicensed communications.
  • the APs 102 or STAs 104, or both also may be capable of communicating over licensed operating bands, where multiple operators may have respective licenses to operate in the same or overlapping frequency ranges.
  • Such licensed operating bands may map to or be associated with frequency range designations of FR1 (410 MHz – 7.125 GHz) , FR2 (24.25 GHz –52.6 GHz) , FR3 (7.125 GHz –24.25 GHz) , FR4a or FR4-1 (52.6 GHz – 71 GHz) , FR4 (52.6 GHz – 114.25 GHz) , and FR5 (114.25 GHz –300 GHz) .
  • Each of the frequency bands may include multiple sub-bands and frequency channels (also referred to as subchannels) .
  • PPDUs conforming to the IEEE 802.11n, 802.11ac, 802.11ax, 802.11be and 802.11bn standard amendments may be transmitted over one or more of the 2.4 GHz, 5 GHz, or 6 GHz bands, each of which is divided into multiple 20 MHz channels.
  • these PPDUs are transmitted over a physical channel having a minimum bandwidth of 20 MHz, but larger channels can be formed through channel bonding.
  • PPDUs may be transmitted over physical channels having bandwidths of 40 MHz, 80 MHz, 160 MHz, 240 MHz, 320 MHz, 480 MHz, or 640 MHz by bonding together multiple 20 MHz channels.
  • FIG 2 shows an example physical layer (PHY) protocol data unit (PPDU) 200 usable for wireless communication between a wireless access point (AP) and one or more wireless stations (STAs) .
  • the AP and STAs may be examples of the AP 102 and the STAs 104 described with reference to Figure 1.
  • the PPDU 200 includes a PHY preamble 202 and a PHY payload 204.
  • the preamble 202 may include a legacy portion that itself includes a legacy short training field (L-STF) 206, which may consist of two symbols, a legacy long training field (L-LTF) 208, which may consist of two symbols, and a legacy signal field (L-SIG) 210, which may consist of two symbols.
  • L-STF legacy short training field
  • L-LTF legacy long training field
  • L-SIG legacy signal field
  • the legacy portion of the preamble 202 may be configured according to the IEEE 802.11a wireless communication protocol standard.
  • the preamble 202 also may include a non-legacy portion including one or more non-legacy fields 212, for example, conforming to one or more of the IEEE 802.11 family of wireless communication protocol standards.
  • the L-STF 206 generally enables a receiving device (such as AP 102 or STA 104) to perform coarse timing and frequency tracking and automatic gain control (AGC) .
  • the L-LTF 208 generally enables the receiving device to perform fine timing and frequency tracking and also to perform an initial estimate of the wireless channel.
  • the L-SIG 210 generally enables the receiving device to determine (for example, obtain, select, identify, detect, ascertain, calculate, or compute) a duration of the PDU and to use the determined duration to avoid transmitting on top of the PDU.
  • the legacy portion of the preamble, including the L-STF 206, the L-LTF 208 and the L-SIG 210 may be modulated according to a binary phase shift keying (BPSK) modulation scheme.
  • BPSK binary phase shift keying
  • the payload 204 may be modulated according to a BPSK modulation scheme, a quadrature BPSK (Q-BPSK) modulation scheme, a quadrature amplitude modulation (QAM) modulation scheme, or another appropriate modulation scheme.
  • the payload 204 may include a PSDU including a data field (DATA) 214 that, in turn, may carry higher layer data, for example, in the form of MAC protocol data units (MPDUs) or an aggregated MPDU (A-MPDU) .
  • MPDUs MAC protocol data units
  • A-MPDU aggregated MPDU
  • FIG 3 shows a hierarchical format of an example PPDU usable for communications between a wireless AP and one or more wireless STAs.
  • the AP and STAs may be examples of the AP 102 and the STAs 104 described with reference to Figure 1.
  • each PPDU 300 includes a PHY preamble 302 and a PSDU 304.
  • Each PSDU 304 may represent (or “carry” ) one or more MAC protocol data units (MPDUs) 316.
  • MPDUs MAC protocol data units
  • each PSDU 304 may carry an aggregated MPDU (A-MPDU) 306 that includes an aggregation of multiple A-MPDU subframes 308.
  • A-MPDU aggregated MPDU
  • Each A-MPDU subframe 306 may include an MPDU frame 310 that includes a MAC delimiter 312 and a MAC header 314 prior to the accompanying MPDU 316, which includes the data portion ( “payload” or “frame body” ) of the MPDU frame 310.
  • Each MPDU frame 310 also may include a frame check sequence (FCS) field 318 for error detection (for example, the FCS field may include a cyclic redundancy check (CRC) ) and padding bits 320.
  • the MPDU 316 may carry one or more MAC service data units (MSDUs) 316.
  • the MPDU 316 may carry an aggregated MSDU (A-MSDU) 322 including multiple A-MSDU subframes 324.
  • Each A-MSDU subframe 324 contains a corresponding MSDU 330 preceded by a subframe header 328 and in some cases followed by padding bits 332.
  • the MAC delimiter 312 may serve as a marker of the start of the associated MPDU 316 and indicate the length of the associated MPDU 316.
  • the MAC header 314 may include multiple fields containing information that defines or indicates characteristics or attributes of data encapsulated within the frame body 316.
  • the MAC header 314 includes a duration field indicating a duration extending from the end of the PPDU until at least the end of an acknowledgment (ACK) or Block ACK (BA) of the PPDU that is to be transmitted by the receiving wireless communication device.
  • the use of the duration field serves to reserve the wireless medium for the indicated duration, and enables the receiving device to establish its network allocation vector (NAV) .
  • NAV network allocation vector
  • the MAC header 314 also includes one or more fields indicating addresses for the data encapsulated within the frame body 316.
  • the MAC header 314 may include a combination of a source address, a transmitter address, a receiver address or a destination address.
  • the MAC header 314 may further include a frame control field containing control information.
  • the frame control field may specify a frame type, for example, a data frame, a control frame, or a management frame.
  • Access to the shared wireless medium is generally governed by a distributed coordination function (DCF) .
  • DCF distributed coordination function
  • a wireless communication device such as an AP 102 or an STA 104
  • IFS inter-frame space
  • IFS provides priority access for control frames used for proper network operation. Transmissions may begin at slot boundaries.
  • IFS short IFS
  • DIFS distributed IFS
  • EIFS extended IFS
  • AIFS arbitration IFS
  • the values for the slot time and IFS may be provided by a suitable standard specification, such as one or more of the IEEE 802.11 family of wireless communication protocol standards.
  • the wireless communication device may implement the DCF through the use of carrier sense multiple access (CSMA) with collision avoidance (CA) (CSMA/CA) techniques.
  • CSMA carrier sense multiple access
  • CA collision avoidance
  • the wireless communication device may perform a clear channel assessment (CCA) and may determine (for example, identify, detect, ascertain, calculate, or compute) that the relevant wireless channel is idle.
  • the CCA includes both physical (PHY-level) carrier sensing and virtual (MAC-level) carrier sensing. Physical carrier sensing is accomplished via a measurement of the received signal strength of a valid frame, which is then compared to a threshold to determine (for example, identify, detect, ascertain, calculate, or compute) whether the channel is busy.
  • Physical carrier sensing also includes energy detection. Energy detection involves measuring the total energy the wireless communication device receives regardless of whether the received signal represents a valid frame. If the total energy detected is above a threshold, the medium is considered busy.
  • Virtual carrier sensing is accomplished via the use of a network allocation vector (NAV) , which effectively serves as a time duration that elapses before the wireless communication device may contend for access even in the absence of a detected symbol or even if the detected energy is below the relevant threshold.
  • NAV network allocation vector
  • the NAV is reset each time a valid frame is received that is not addressed to the wireless communication device.
  • the wireless communication device performs the physical carrier sensing. If the channel remains idle for the appropriate IFS, the wireless communication device initiates a backoff timer, which represents a duration of time that the device senses the medium to be idle before it is permitted to transmit.
  • the wireless communication device becomes the holder (or “owner” ) of a transmit opportunity (TXOP) and may begin transmitting.
  • TXOP is the duration of time the wireless communication device can transmit frames over the channel after it has “won” contention for the wireless medium.
  • the TXOP duration may be indicated in the U-SIG field of a PPDU. If, on the other hand, one or more of the carrier sense mechanisms indicate that the channel is busy, a MAC controller within the wireless communication device will not permit transmission.
  • the available distribution of the numbers that may be randomly selected for the backoff timer is referred to as the contention window (CW) .
  • CW contention window
  • the wireless communication device may contend for access to the wireless medium of WLAN 100 in accordance with an enhanced distributed channel access (EDCA) procedure.
  • EDCA enhanced distributed channel access
  • a random channel access mechanism such as EDCA may afford high-priority traffic a greater likelihood of gaining medium access than low-priority traffic.
  • the wireless communication device using EDCA may classify data into different access categories. Each AC may be associated with a different priority level and may be assigned a different range of random backoffs (RBOs) so that higher priority data is more likely to win a TXOP than lower priority data (such as by assigning lower RBOs to higher priority data and assigning higher RBOs to lower priority data) .
  • RBOs random backoffs
  • EDCA increases the likelihood that low-latency data traffic will gain access to a shared wireless medium during a given contention period, unpredictable outcomes of medium access contention operations may prevent low-latency applications from achieving certain levels of throughput or satisfying certain latency requirements.
  • Some APs and STAs may implement techniques for spatial reuse that involve participation in a coordinated communication scheme.
  • an AP 102 may contend for access to a wireless medium to obtain control of the medium for a TXOP.
  • the AP that wins the contention (hereinafter also referred to as a “sharing AP” ) may select one or more other APs (hereinafter also referred to as “shared APs” ) to share resources of the TXOP.
  • the sharing and shared APs may be located in proximity to one another such that at least some of their wireless coverage areas at least partially overlap.
  • Some examples may specifically involve coordinated AP TDMA or OFDMA techniques for sharing the time or frequency resources of a TXOP.
  • the sharing AP may partition the TXOP into multiple time segments or frequency segments each including respective time or frequency resources representing a portion of the TXOP.
  • the sharing AP may allocate the time or frequency segments to itself or to one or more of the shared APs.
  • each shared AP may utilize a partial TXOP assigned by the sharing AP for its uplink or downlink communications with its associated STAs.
  • each portion of the plurality of portions of the TXOP includes a set of frequency resources that do not overlap with any frequency resources of any other portion of the plurality of portions.
  • the scheduling information may include an indication of frequency resources, of multiple frequency resources of the TXOP, associated with each portion of the TXOP.
  • the scheduling information may include an indication of a bandwidth portion of the wireless channel such as an indication of one or more subchannels or resource units associated with each portion of the TXOP such as for multi-user OFDMA.
  • the sharing AP’s acquisition of the TXOP enables communication between one or more additional shared APs and their respective BSSs, subject to appropriate power control and link adaptation.
  • the sharing AP may limit the transmit powers of the selected shared APs such that interference from the selected APs does not prevent STAs associated with the TXOP owner from successfully decoding packets transmitted by the sharing AP.
  • Such techniques may be used to reduce latency because the other APs may not need to wait to win contention for a TXOP to be able to transmit and receive data according to conventional CSMA/CA or enhanced distributed channel access (EDCA) techniques.
  • EDCA enhanced distributed channel access
  • such techniques may increase throughput across the BSSs associated with the participating APs and also may achieve improvements in throughput fairness.
  • medium utilization may be maximized or otherwise increased while packet loss resulting from OBSS interference is minimized or otherwise reduced.
  • Various implementations may achieve these and other advantages without requiring that the sharing AP or the shared APs be aware of the STAs 104 associated with other BSSs, without requiring a preassigned or dedicated master AP or preassigned groups of APs, and without requiring backhaul coordination between the APs participating in the TXOP.
  • the AP 102 and STAs 104 can support various multi-user communications; that is, concurrent transmissions from one device to each of multiple devices (for example, multiple simultaneous downlink communications from an AP 102 to corresponding STAs 104) , or concurrent transmissions from multiple devices to a single device (for example, multiple simultaneous uplink transmissions from corresponding STAs 104 to an AP 102) .
  • the AP 102 and STAs 104 may support OFDMA.
  • OFDMA is in some aspects a multi-user version of OFDM.
  • the available frequency spectrum of the wireless channel may be divided into multiple resource units (RUs) each including multiple frequency subcarriers (also referred to as “tones” ) .
  • RUs resource units
  • Different RUs may be allocated or assigned by an AP 102 to different STAs 104 at particular times.
  • the sizes and distributions of the RUs may be referred to as an RU allocation.
  • RUs may be allocated in 2 MHz intervals, and as such, the smallest RU may include 26 tones consisting of 24 data tones and 2 pilot tones. Consequently, in a 20 MHz channel, up to 9 RUs (such as 2 MHz, 26-tone RUs) may be allocated (because some tones are reserved for other purposes) .
  • a 160 MHz channel up to 74 RUs may be allocated.
  • Other tone RUs also may be allocated, such as 52 tone, 106 tone, 242 tone, 484 tone and 996 tone RUs.
  • Adjacent RUs may be separated by a null subcarrier (such as a DC subcarrier) , for example, to reduce interference between adjacent RUs, to reduce receiver DC offset, and to avoid transmit center frequency leakage.
  • a null subcarrier such as a DC subcarrier
  • an AP 102 can transmit a trigger frame to initiate and synchronize an UL OFDMA or UL MU-MIMO transmission from multiple STAs 104 to the AP 102.
  • trigger frames may thus enable multiple STAs 104 to send UL traffic to the AP 102 concurrently in time.
  • a trigger frame may address one or more STAs 104 through respective association identifiers (AIDs) , and may assign each AID (and thus each STA 104) one or more RUs that can be used to send UL traffic to the AP 102.
  • the AP also may designate one or more random access (RA) RUs that unscheduled STAs 104 may contend for.
  • RA random access
  • Some wireless communication devices are capable of multi-link operation (MLO) .
  • MLO supports establishing multiple different communication links (such as a first link on the 2.4 GHz band, a second link on the 5 GHz band, and the third link on the 6 GHz band) between the STA and the AP.
  • Each communication link may support one or more sets of channels or logical entities.
  • each communication link associated with a given wireless communication device may be associated with a respective radio of the wireless communication device, which may include one or more transmit/receive (Tx/Rx) chains, include or be coupled with one or more physical antennas, or include signal processing components, among other components.
  • Tx/Rx transmit/receive
  • An MLO-capable device may be referred to as a multi-link device (MLD) .
  • an AP MLD may include multiple APs each configured to communicate on a respective communication link with a respective one of multiple STAs of a non-AP MLD (also referred to as a “STA MLD” ) .
  • the STA MLD may communicate with the AP MLD over one or more of the multiple communication links at a given time.
  • a single user access mode is associated with contention-based access in which an STA obtains the use of the full channel in the form of a transmit opportunity (TxOP) when it wins contention.
  • OFDMA orthogonal frequency division multiple access
  • UL-MU uplink multi-user
  • MU EDCA multi-user enhanced distributed controlled access
  • the AP 102 may allocate portions of an Uplink (UL) MU PPDU to different STAs 104.
  • OFDMA and the MU EDCA access the AP 102 may trigger contention-based access for portions of a transmission opportunity by various STAs 104.
  • the AP 102 may send one or more trigger messages or frames to one or more STAs 104 to cause the STAs 104 to send their uplink data in response to the trigger message.
  • the AP 102 may determine a schedule for the uplink data in accordance with feedback from the STAs. For example, the AP 102 may transmit to the STAs 104 a Buffer Status Report Poll (BSRP) trigger frame, and in response, the STAs 104 may provide feedback to the AP 102 with a Buffer Status Report (BSR) .
  • the feedback from the STAs 104 in the Buffer Status Report (BSR) may indicate an amount of data available for uplink transmission from each STA 104.
  • BSRP Buffer Status Report Poll
  • BSR Buffer Status Report
  • the AP 102 may send another trigger frame, a MU Request to Send (MU-RTS) trigger frame, indicating which STAs 104 can simultaneously transmit data back to the AP 102.
  • the STAs 104 may respond by sending a clear to send (CTS) message to the AP 102.
  • CTS clear to send
  • the AP 102 may then send another trigger frame effectively initiating the simultaneous uplink MU-OFDMA transmissions.
  • This trigger frame may include a number of frequency-division-multiplexed resource units (RUs) that may be assigned to one or more STAs 104 and may be used for uplink transmissions from the STAs. These trigger frames may enable multiple STAs 104 to send uplink traffic to the AP 102 concurrently in time over different frequencies.
  • the trigger frame may address one or more STAs 104 through an association identification (AID) for each STA 104, and may assign each association identification (AID) to one or more unique resource units (RUs) that can be used to send uplink traffic to the AP 102.
  • a “resource unit, ” or “RU, ” as the term is used herein, includes a multiple resource unit (MRU) . In MRUs, puncturing of overlapping portions of the spectrum is used to enhance interference mitigation and increase reliability and data rates.
  • MRU multiple resource unit
  • An AP 102 also may configure one or more RUs of a trigger frame for random access. In this situation, multiple STAs 104 can contend to use the random access RUs. In some cases, separate subsets of random access RUs may be identified for STAs 104 that are associated and unassociated with the AP 102, and the AP 102 may assign different numbers of random access RUs for associated versus unassociated STAs 104. For example, an AP 102 may identify that a number of associated STAs 104 are uplink- limited, and may provide additional random access RUs that are available to associated STAs 104 and fewer random access RUs that are available for unassociated STAs.
  • the AP 102 may acknowledge uplink transmissions that are transmitted in random access RUs.
  • the AP 102 may, in some cases, transmit an acknowledgment of an uplink transmission in a random access RU using an acknowledgment frame in a downlink RU having a same AID as the AID of the particular random access RU.
  • Figure 4 shows a table 400 categorizing example types of low-latency packets.
  • the AP 102 or the STAs 104, or both may support applications associated with high throughput or low-latency (including ultra-low latency (ULL) ) requirements.
  • Each packet may have a size (such as a small size or a large size) , may be associated with one of an uplink (or upstream) transmission or a downlink (or downstream) transmission, and may be periodic or event-based (such as, may be associated with the meeting of a specified condition or the occurrence of another event) .
  • the AP 102 may have sufficient time and information to ensure that the packet is addressed appropriately. That is, since the low-latency packet is being transmitted by the AP 102, the AP 102 may schedule the packet with the highest priority or a suitably high priority by allocating an appropriately sized RU. If the low-latency packet is a periodic packet, the AP 102 may allocate an appropriately sized RU to the low-latency packet periodically. If the low-latency packet is an event-driven packet, the AP 102 may allocate an appropriately sized RU to the low-latency packet instantaneously or generally instantaneously upon the occurrence of the event.
  • the STA 104 associated with the low-latency packet may provide the AP 102 information about the periodic low-latency packet (such as the size and frequency thereof) during setup, and the AP 102 may periodically reserve an appropriate RU for these packets in view of the information provided by the STA 104 during setup. That is, once the AP 102 is made aware by the STA 104 of the requirement for periodic upstream transmission during setup, the AP 102 may use this information to periodically reserve the RUs for these packets in advance.
  • the AP 102 may address the low-latency packet by upstream OFDMA-based Random Access (UORA) .
  • UORA is a mixed channel access mechanism.
  • the AP 102 may transmit a minimum value of OFDMA contention window OCW (i.e., OCWmin) and a maximum value of OCW (i.e., OCWmax) for OCW determination of each STA 104 through a random access parameter set.
  • the random access parameter set may be transmitted by being contained in at least one of a beacon, a probe response, an association or reassociation response, and an authentication response.
  • An STA 104 that initially attempts the UL OFDMA-based random access may set the OCW of the corresponding STA to ‘OCWmin-1’ in accordance with the received random access parameter set. Next, the STA 104 may select an arbitrary integer within the range from 0 to OCW to obtain the OBO counter. If the STA 104 has data to transmit, the STA 104 may decrement its OBO counter by the number of RUs on which random access can be performed each time a trigger frame is transmitted. That is, when N RUs are allocated to the random access, the STA 104 that has data to send may decrement the OBO counter by a maximum of N in the random access contention of the UL-MU transmission process by the corresponding trigger frame.
  • the OBO counter of the STA 104 may be decremented. Where the OBO counter is zero or decremented to zero, the STA 104 may randomly select at least one of RU (s) allocated for random access and perform an UL-MU transmission via the selected resource unit (s) . An STA 104 that has failed to decrement the OBO counter to zero in the corresponding contention process may attempt random access by repeating the above-described OBO counter decrementing process when the next trigger frame is transmitted.
  • the AP 102 may pre-reserve a small RU for the packet.
  • the small size of the pre-reserved RU may limit the bandwidth that is wasted in situations where the RU is not used to send a packet (such as where the event associated with the low-latency packet does not occur) .
  • the AP 102 may address the packet in one of several ways. For example, the AP 102 may employ traditional CSMA/CA to address the large-sized, low-latency, event-based packet.
  • the traditional CSMA/CA may have a long backoff period, which may lead to unexpected and unbounded delays.
  • the AP 102 may address a large-sized, low-latency, event-based, upstream packet (category 408) using trigger-based US-OFDMA. For example, the AP 102 may provide some blank RUs for which the STAs 104 may compete using UORA. However, as the low-latency packet is event-based, the AP 102 may not have any information beforehand about when the packet will be ready to be transmitted by the STA or the size thereof. The STA 104 associated with the large-sized, low-latency, event-based packet may fail to win the RUs by UORA if the available number of RUs is smaller than the number of competing STAs 104 or where two or more STAs 104 are competing for the same RU.
  • the AP 102 may address a large-sized, low-latency, event-based, upstream packet (category 408) by pre-reserving an RU for the STA 104 in association with that packet. However, it may not be possible for the AP 102 to ensure that the pre-reserved RU has a time interval for transmission that is less than the latency constraint of the packet. Further, both when employing UORA and when pre-reserving RUs, considering that the packet size is large, a large amount of bandwidth may be wasted (such as when the RU is unused) –which is inefficient. Further, these methods for handling large-sized, low-latency, event-based packets may not guarantee low-latency transmission of these large packets in accordance with their respective low-latency Quality of Service (QOS) requirements.
  • QOS Quality of Service
  • FIG. 5 shows an example Buffer Status Report (BSR) Control Information subfield 500 as defined in IEEE 802.11ax or defined for operation in a subsequent generation of the IEEE 802.11 family of wireless communication protocol standards.
  • BSR Buffer Status Report
  • Another problem with using trigger-based OFDMA approaches, such as UORA or pre-reserved RUs, for large-sized, event-driven, upstream packets (category 408 in Figure 4) stems from the contents of Buffer Status Report (BSR) .
  • the BSR Control Information subfield 500 may be transmitted by an STA 104 to the AP 102 and may contain buffer status information used for UL MU operation.
  • Control Information subfield 500 also may be referred to as a “field, ” “an information element, ” an “element, ” or a “subelement, ” which may be considered interchangeable terms for purposes of discussion herein.
  • the BSR Control Information subfield 500 may have an ACI Bitmap subfield 502, a Delta TID subfield 504, an ACI High subfield 506, a Scaling Factor subfield 508, a Queue Size High subfield 510, and a Queue Size All subfield 512.
  • the ACI Bitmap subfield 502 may indicate the access categories (AC) for which the buffer status is reported. Specifically, each bit of the ACI Bitmap subfield may be set to 1 to indicate the buffer status of the corresponding AC, and may be set to 0 otherwise.
  • the Delta TID subfield 504, together with the values of the ACI Bitmap subfield 502, may indicate the number of TIDs for which the STA 104 is reporting the buffer status.
  • the ACI High subfield 506 may indicate the adjacent channel interference (ACI) of the AC for which the BSR is indicated in the Queue Size High subfield 510.
  • the Scaling Factor subfield 508 may indicate the unit scaling factor (SF) , in octets, of the Queue Size High subfield 510 and Queue Size All 512 subfield.
  • the Queue Size All subfield 512 may indicate the amount of buffered traffic for all access categories (ACs) identified by the ACI Bitmap subfield 502.
  • the subfield 500 does not include any time information to allow the AP 102 to schedule an appropriate RU to ensure that the latency constraints of the packet are met. Further, in the BSR Control subfield 500, the total size of the same access category (AC) packets are reported as a whole. That is, the BSR Control Information subfield 500 does not differentiate between the size of low-latency MAC Service Data Units (MSDUs) and the size of other (such as non-low-latency) MSDUs in the same access category.
  • MSDUs low-latency MAC Service Data Units
  • the AP 102 may be unable to timely allocate an appropriately sized RU for the MSDU. It may be desirable for the AP 102 to have time information associated with the large-sized, low-latency, event-based, upstream MSDU and for the AP 102 to know of the size of the low-latency MSDU independent of other MSDUs in the same access category (AC) .
  • AC access category
  • FIG. 6 shows a schematic 600 illustrating an example path 602 for a low-latency packet as it is internally processed and transmitted by STA 104.
  • a low-latency application may generate a low-latency packet (such as a large, event-based MSDU) in the user space.
  • the low-latency MSDU may be conveyed by the application to the WLAN driver/kernel of the STA 104.
  • the kernel/WLAN driver may process the low-latency MSDU and the low-latency MSDU may thereafter be conveyed to the WLAN firmware of the STA 104.
  • the WLAN firmware of the STA 104 may process the MSDU, and from there, the low-latency MSDU may be conveyed to the WLAN hardware.
  • the WLAN hardware may process the MSDU, and at time Ta, the low-latency MSDU may leave the STA 104, such as to be wirelessly transmitted to the AP 102. It takes a non-zero amount of time, illustrated in in Figure 6 as ⁇ T, for the STA 104 to process the low-latency packet internally via path 602 from the user space to the WLAN hardware where the MSDU is ultimately transmitted. That is, it takes the event-driven low-latency packet a non-zero time ⁇ T to be processed internally by the STA 104 via path 602 before it is transmitted at time Ta.
  • the STA 104 may convey information about the event-driven low-latency packet to the AP 102 while the low-latency packet is being internally processed by the STA 104.
  • the AP 102 may use this information about the low-latency packet to allocate an appropriate RU for the transmission of the MSDU by the STA 104.
  • Figure 7 shows a schematic 700 illustrating a path 704 taken by a pre-request information element 706 associated with a low-latency MAC Service Data Unit (MSDU) .
  • MSDU low-latency MAC Service Data Unit
  • Figure 7 illustrates the low-latency packet being generated by the low-latency application and being routed to the driver, the WLAN firmware, and ultimately, the WLAN hardware, in much the same way as shown in Figure 6.
  • Path 702 of Figure 7 generally corresponds to path 602 of Figure 6.
  • the low-latency MSDU takes a non-zero amount of time (shown in Figure 7 as ⁇ T) to be internally processed and transmitted by the WLAN hardware.
  • Time T3 (expected time) in Figure 7 is the time at which the MSDU is expected to be transmitted by the WLAN hardware of the STA 104 after the MSDU has been internally processed.
  • Figure 7 also shows a pre-request information element 706 being transmitted to the WLAN hardware, specifically to the hardware scheduler, via a different path 704.
  • the pre-request information element 706 is not processed by the kernel/driver or WLAN firmware, but instead, is communicated from the user space to the hardware scheduler directly.
  • the pre-request information element 706 includes the size of the low-latency MSDU that is expected to be transmitted at time T3. In some aspects, the pre-request information element 706 further includes timing information associated with the low-latency MSDU (such as includes time T3 at which the MSDU is expected to be transmitted by the WLAN hardware of STA 104) .
  • the pre-request information element 706 may be triggered or generated at time T1 as soon as the low-latency application becomes aware that it is to transmit a low-latency MSDU, or shortly thereafter.
  • the pre-request information element 706 may include size of the MSDU and the time at which the MSDU is expected to be transmitted by the hardware in the future (i.e., time T3) .
  • the hardware scheduler of the STA 104 may send out the MPDU with the pre-request information element 706 associated with the low-latency MSDU at time T2.
  • time T2 may occur before time T3. That is, the pre-request information element 706 that includes information about the low-latency MSDU and is transmitted at time T2 may be transmitted prior to the low-latency MSDU expected to be transmitted at time T3.
  • the STA 104 takes advantage of the internal delay (duration ⁇ T) it takes for the low-latency MSDU to be processed, and provides information to the AP 102 about the low-latency MSDU while the MSDU is being internally processed.
  • the STA 104 may transmit the pre-request IE 706 to AP 102 using a small size RU.
  • the STA 104 may transmit the pre-request IE 706 to AP 102 using UORA.
  • information provided by the STA 104 to the AP 102 via the pre-request information element 706 may include a size of the MSDU and the time T3 at which the MSDU is expected to be transmitted by the STA 104.
  • the AP 102 may use the information supplied in the pre-request information element 706 to timely schedule an appropriately sized RU for the upcoming low-latency MSDU.
  • duration D4 demarcates the time between time T1 and time T2, i.e., duration D4 is the duration between the triggering of the pre-request IE 706 (at or about time T1) and the transmission of the PPDU containing the pre-request IE 706 (at time T2) .
  • the hardware scheduler may prepare the PPDU that includes the pre-request IE 706 during the duration D4. In some examples, it may be beneficial for duration D4 to be as short as possible, so that the AP 102 is apprised of the size and timing of the upcoming low-latency MSDU as soon as possible.
  • Duration D5 demarcates the time between time T2 and time T3, i.e., duration D5 is the duration between the time at which the PPDU including the pre-request IE 706 is transmitted (at time T2) and the time at which the MSDU is expected to be transmitted (at time T3) .
  • duration D5 it may be beneficial for duration D5 to be as long as possible. Having a relatively longer duration D5 may ensure that the AP 102 has sufficient time to allocate a RU for the upcoming low-latency MSDU. Further, having a longer duration D5 may allow the AP 102 multiple opportunities to assign an RU for the upcoming MSDU (i.e., the AP 102 may assign an RU for the upcoming MSDU two or more times) .
  • Duration D6 demarcates the time between time T1 and time T3, i.e., duration D6 is the duration between the triggering of the pre-request IE 706 (at time T1) and the time at which the MSDU is expected to be transmitted (at time T3) . Duration D6 is the same as duration ⁇ T. In some examples, having a longer D6 may be beneficial as it may provide the AP 102 more opportunities to schedule the RU for the upcoming MSDU.
  • the STA 104 internally triggers a MPDU ahead of the event-based low-latency MSDU by providing to the AP 102 the size of the MSDU, the time at which the MSDU is expected to be transmitted, and other useful information.
  • the STA may transmit the MPDU (also referred to herein as a “pre-request” ) including this information to the AP 102 using a small-size RU through UORA or via a pre-reserved RU as soon as practical.
  • the AP 102 may receive the pre-request and send to the STA 104 a trigger frame that includes an appropriately sized RU assigned to the upcoming low-latency MSDU.
  • the STA may receive the trigger frame and transmit the event-based packet using the assigned RU with bounded delay, such as a delay that does not exceed a low-latency requirement associated with the packet. While Figure 7 shows a solitary MSDU, one or more STAs may transmit to an AP like pre-requests each associated with one of a plurality of MSDUs.
  • Figure 8 shows a flowchart illustrating an example process 800 performable by an STA to provide information to an AP about a low-latency packet prior to the transmission of the low-latency packet.
  • the STA (such as STA 104) may transmit, to a wireless Access Point (such as AP 102) , a first frame including an indication that STA has data to transmit.
  • a wireless Access Point such as AP 102
  • the data to be transmitted by the STA may include a large-sized, low-latency, event-based packet.
  • the first frame may include an indication of a size associated with the data, and an indication of a transmission time associated with transmitting the data in accordance with a latency constraint.
  • the first frame may be or may include the pre-request information element 706 discussed in more detail herein.
  • the STA may receive, from the AP prior to the transmission time, and in association with transmission of the first frame, a trigger frame that includes a resource allocation identifying one or more resource units associated with the size for transmitting the data.
  • the STA may transmit, to the AP in accordance with the transmission time and via the one or more resource units, a data frame that includes the data.
  • Figure 9 shows a flowchart illustrating an example process 900 performable by an AP to allocate to an STA an appropriately sized RU for an upcoming low-latency, event-driven packet in accordance with information previously supplied by the STA.
  • the AP (such as AP 102) may receive, from an STA, a first frame including an indication that the STA has data to transmit.
  • the indication may include a size of the data and an expected transmission time of the data.
  • the data may be or may include a low-latency, event-driven packet.
  • the AP may transmit to the STA a trigger frame that includes one or more resource units allocated to the data.
  • the AP may transmit the trigger frame before the expected transmission time of the packet.
  • the AP may receive, from the STA via the one or more resource units, a data frame that includes the data.
  • Figure 10 shows a schematic 1000 illustrating the use of a pre-request information element 1008 by an STA to inform an AP of an upcoming low-latency MSDU.
  • the upper portion of Figure 10 corresponds generally to Figure 7.
  • path 1010 and path 1006 in Figure 10 respectively correspond to path 702 and path 704 in Figure 7.
  • the AP may send a trigger frame TF1 to an STA (such as the STA 104) .
  • the trigger frame TF1 may include a small-size RU 1002 pre-preserved for the pre-request, such as the pre-request information element 706 shown in Figure 7.
  • the STA may respond to the trigger frame TF1 by sending to the AP data using upstream OFDMA (US-OFDMA-1) . Because the low-latency MSDU has not been generated at this time, and consequently, the pre-request information element including information about the MSDU has not been triggered, the STA may not employ the pre-reserved RU 1002.
  • US-OFDMA-1 includes a communication from the STA to the AP where the resource unit 1004 corresponding to the resource unit 1002 is unused. AP may continue to send trigger frames to the STA and the STA may continue to send data to the AP using OFDMA.
  • the low-latency application may subsequently generate a MSDU (such as a large sized, low-latency MSDU) .
  • a MSDU such as a large sized, low-latency MSDU
  • the pre-request information element 1008 may be triggered in association with the MSDU.
  • the pre-request information element 1008 may generally correspond to the pre-request information element 706 in Figure 7, and may include size, time, or other useful information about the MSDU.
  • the pre-request information element 1008 may include a size of the MSDU and the expected time of transmission of the MSDU.
  • the AP may transmit a trigger frame TF2 to the STA after time T1 and before time T2.
  • This trigger frame TF2 may likewise include a small-size resource unit 1012 allocated to the pre-request.
  • the pre-request may be sent by the STA to the AP using resource unit 1014 that corresponds to the resource unit 1012.
  • the pre-request MPDU transmitted using the resource unit 1014 may provide the AP useful information about the upcoming MSDU.
  • the AP may use the information supplied in the pre-request information element 1008 to timely allocate an appropriately sized RU 1016 for the MSDU.
  • the RU 1016 may be sized to accommodate the MSDU and may be transmitted to the STA in a trigger frame TFN prior to time T3 (which is when the STA is expected to transmit the MSDU) .
  • T3 time T3
  • the internal processing of the MSDU may be completed and the STA may transmit the MSDU via US-OFDMA-N using the RU 1018 that corresponds to the RU 1016.
  • the STA and AP may, in effect, take advantage of the time it takes for the STA to internally process the MSDU during duration ⁇ T, and within this duration, the STA may apprise the AP of the upcoming MSDU and the AP may timely allocate an appropriately sized RU for this MSDU.
  • Figure 11 shows a schematic 1100 illustrating an STA transmitting to an AP a plurality of pre-requests associated with a low-latency MSDU prior to transmitting the low-latency MSDU.
  • the path 1102, path 1104, and pre-request information element 1106 generally correspond respectively to the path 702, the path 704, and the pre-request information element 706 described with reference to Figure 7.
  • time T1 indicates the time at which the pre-request is triggered
  • time T2 indicates the time at which the pre-request is initially transmitted to the AP
  • time T3 indicates the time at which the low-latency MSDU is expected to be transmitted to the AP.
  • the AP may schedule one or more additional trigger frames with a small-sized RU reserved for the pre-request.
  • the STA may have two or more opportunities to transmit the pre-request associated with the MSDU to the AP, and in some examples, may transmit more than one pre-request associated with the same MSDU to the AP.
  • the AP and STA are multi-link devices (MLDs)
  • the AP may schedule these RUs for the pre-request IE 1106 over two or more links.
  • the pre-request may be transmitted at different times in single-link operation and may be sent at the same or different times in multi-link operation (MLO) .
  • MLO multi-link operation
  • Figure 12 shows a schematic 1200 illustrating an STA having multiple opportunities to transmit a low-latency MSDU to an AP.
  • the path 1202, path 1204, and pre-request information element 1206 generally correspond respectively to the path 702, the path 704, and the pre-request information element 706 described with reference to Figure 7.
  • time T1 indicates the time at which the pre-request is triggered
  • time T2 indicates the time at which the pre-request is initially transmitted to the AP
  • time T3 indicates the time at which the low-latency MSDU is expected to be transmitted to the AP.
  • Time T4 in Figure 12 indicates the time after which the latency constraint of the low-latency MSDU is unmet.
  • the AP may schedule two or more trigger frames each with a pre-reserved RU for the pre-request information element, over the same link or on two or more different links. Such may provide the STA a more robust opportunity to communicate the pre-request to the AP.
  • the AP may schedule after time T3 and before time T4 one or more additional trigger frames each with an RU allocated for the low-latency MSDU. Where the AP and STA are MLD devices, the AP may schedule these RUs over two or more links. Such may provide the STA a more robust opportunity to transmit the low-latency MSDU to the AP as soon as possible.
  • Figure 13 shows an example pre-request information element 1300 usable to provide an AP information about an upcoming low-latency MSDU.
  • the pre-request information element 1300 may be an example of the pre-request information element 706 discussed with reference to Figure 7, the pre-request information element 1008 discussed with reference to Figure 10, the pre-request information element 1106 discussed with reference to Figure 11, or the pre-request information element 1206 discussed with reference to Figure 12.
  • the pre-request information element 1300 may include a dialog token field 1302, an expected time field 1304, a time window field 1306, a scaling factor field 1308, a MSDU size field 1310, and a scheduled link ID field 1312.
  • the dialog token field 1302 may be one octet in length.
  • the dialog token field 1302 may be used by the AP to distinguish one pre-request from another.
  • the AP may receive multiple pre-requests associated with the same or different MSDUs, over the same link, or over different links.
  • the dialog token field 1302 may allow the AP to distinguish a pre-request associated with an MSDU with other pre-request (s) associated with other MSDU (s) .
  • the expected time field 1304 may be eight octets in length and may include, in timing synchronization function (TSF) , the time at which the low-latency MSDU is expected to be transmitted to the AP (i.e., time T3 in Figure 7) .
  • TSF timing synchronization function
  • the time window field 1306 may be two octets in length and may indicate a low-latency constraint of the MSDU.
  • the low-latency MSDU may be required to be transmitted within a certain time period (such as before time period T4 in Figure 12, after which the latency constraint of the MSDU is unmet) .
  • the STA may transmit the MSDU to the AP at any time between time T3 and time T4. If, however, the MSDU is not transmitted by time T4, the STA may drop the MSDU as it no longer meets the low-latency constraint.
  • the scaling factor field 1308 may be one octet in length and may generally provide the same information as the scaling factor subfield 508 discussed with reference to the Buffer Status Report (BSR) Control Information subfield 500.
  • BSR Buffer Status Report
  • the MSDU size field 1310 may be one octet in length and may include a size of the low-latency MSDU.
  • the scheduled link Id field 1312 may be two octets in length and, when the STA and AP are communicating over multiple links, may indicate which links are available for the scheduling of an RU by the AP.
  • Figure 14 shows a block diagram of an example wireless communication device 1400 that supports sending or receiving a pre-request associated with an upcoming MSDU, according to some aspects of the present disclosure.
  • the wireless communication device 1400 is configured or operable to perform all or part of the process 800 described with reference to Figure 8.
  • the wireless communication device 1400 is configured or operable to perform all or part of the process 900 described with reference to Figure 9.
  • the wireless communication device 1400 is configured or operable to perform all or part of the processes schematically described with reference to Figure 7, Figure 10, Figure 11, and Figure 12.
  • the wireless communication device 1400 can be a chip, SoC, chipset, package or device that may include: one or more modems (such as a Wi-Fi modem or a cellular modem such as 3GPP 4G LTE or 5G compliant modem) ; one or more processors, processing blocks or processing elements (collectively “the processor” 1402) ; one or more radios (collectively “the radio” 1412) ; and one or more memories or memory blocks (collectively “the memory” 1404) .
  • modems such as a Wi-Fi modem or a cellular modem such as 3GPP 4G LTE or 5G compliant modem
  • the processors processing blocks or processing elements
  • radios collectively “the radio” 1412
  • memories or memory blocks collectively “the memory” 1404
  • the wireless communication device 1400 includes a processor component 1402, a memory component 1404, and display component 1406, a user interface component 1408, a modem component 1410, and a radio component 1412. Portions of one or more of the components 1406, 1408, 1410, and 1412 may be implemented at least in part in hardware or firmware. In some examples, at least some of the components 1406, 1408, 1410, and 1412 of the device 1400 are implemented at least in part by a processor and as software stored in a memory. For example, portions of one or more of the display component 1406, the user interface component 1408, and the modem component 1410 can be implemented as non-transitory instructions (or “code” ) executable by the processor 1402 to perform the functions or operations of the respective module.
  • the processor 1402 may be a component of a processing system.
  • a processing system may generally refer to a system or series of machines or components that receives inputs and processes the inputs to produce a set of outputs (which may be passed to other systems or components of, for example, the device 1400) .
  • a processing system of the device 1400 may refer to a system including the various other components or subcomponents of the device 1400, such as the processor, or a transceiver, or a communications manager, or other components or combinations of components of the device 1400.
  • the processing system of the device 1400 may interface with other components of the device 1400 and may process information received from other components (such as inputs or signals) or output information to other components.
  • a chip or modem of the device 1400 may include a processing system, a first interface to output information and a second interface to obtain information.
  • the first interface may refer to an interface between the processing system of the chip or modem and a transmitter, such that the device 1400 may transmit information output from the chip or modem.
  • the second interface may refer to an interface between the processing system of the chip or modem and a receiver, such that the device 1400 may obtain information or signal inputs, and the information may be passed to the processing system.
  • the first interface also may obtain information or signal inputs
  • the second interface also may output information or signal outputs.
  • the processor 1402 is capable of, configured to, or operable to processes information received through the radio 1412 and the modem 1410, and processes information to be output through the modem 1410 and the radio 1412 for transmission through the wireless medium.
  • the processor 1402 may perform logical and arithmetic operations using program instructions stored within the memory 1404.
  • the instructions in the memory 1404 may be executable (by the processor 1402, for example) to implement the methods described herein.
  • the processor 1402 together with the memory 1404, are capable of, configured to, or operable to: communicate traffic over a first link; identify an event associated with an upcoming service-level agreement (SLA) breach for a SLA-aware device operating on the first link; and transmit a traffic identifier (TID) to link (TID-to-link) mapping scheme in association with unavailability information based at least in part on the event associated with the upcoming SLA breach, where the unavailability information indicates an unavailability associated with the first link, and where the TID-to-link mapping scheme is configured to map at least one TID to a second link other than the first link.
  • TID traffic identifier
  • TID-to-link mapping scheme is configured to map at least one TID to a second link other than the first link.
  • the memory 1404 is capable of, configured to, or operable to store and communicate instructions and data to and from the processor 1402.
  • the user interface 1408 may be any device that allows a user to interact with the wireless communication device 1400, such as a keyboard, a mouse, a microphone, et cetera. In aspects, the user interface 1408 may be integrated with the display component 1406 to present a touchscreen.
  • the modem 1410 is capable of, configured to, or operable to modulate packets and to output the modulated packets to the radio 1412 for transmission over the wireless medium.
  • the modem 1410 is similarly configured to obtain modulated packets received by the radio 1412 and to demodulate the packets to provide demodulated packets.
  • the radio 1412 includes at least one radio frequency transmitter and at least one radio frequency receiver, which may be combined into one or more transceivers.
  • the transmitter (s) and receiver (s) may be coupled to one or more antennas.
  • the processor 1402, the memory 1404, the modem 1410, and the radio 1412 may collectively facilitate the wireless communication of the wireless communication device 1400 with other wireless communication devices over multiple frequency bands (such as 2.4 GHz, 5 GHz, or 6 GHz) .
  • the wireless communication device 1400 can be a device for use in an STA, such as the STA 104 described with reference to Figure 1, or another suitable STA.
  • the wireless communication device 1400 can be an STA that includes such a chip, SoC, chipset, package, or device as well as multiple antennas.
  • the wireless communication device 1400 is capable of transmitting and receiving wireless communications in the form of, for example, wireless packets.
  • the wireless communication device can be configured or operable to transmit and receive packets in the form of physical layer PPDUs and MPDUs conforming to one or more of the IEEE 802.11 family of wireless communication protocol standards.
  • the wireless communication device 1400 also includes or can be coupled with an application processor which may be further coupled with another memory.
  • the wireless communication device 1400 further includes a user interface (UI) (such as a touchscreen or keypad) and a display, which may be integrated with the UI to form a touchscreen display.
  • UI user interface
  • the wireless communication device 1400 may further include one or more sensors such as, for example, one or more inertial sensors, accelerometers, temperature sensors, pressure sensors, or altitude sensors.
  • aspects of the disclosure may support upstream event-based low latency service with bounded delay, such as with the use of a pre-request information element that apprises the AP of an upcoming MSDU ahead of time.
  • the MSDU may be a large, event-driven MSDU, which are not traditionally handled in an efficient manner.
  • a wireless station including:
  • a wireless access point AP
  • a first frame including an indication that the STA has data to transmit, an indication of a size associated with the data, and an indication of a transmission time associated with transmitting the data in accordance with a latency constraint
  • a trigger frame that includes a resource allocation identifying one or more resource units associated with the size for transmitting the data
  • an initial trigger frame including eligible random access resource units and an Orthogonal Frequency Division Multiple Access (OFMDA) counter;
  • a wireless access point including:
  • a processing system that includes one or more processors and one or more memories coupled with the one or more processors, the processing system configured to cause the AP to:
  • a method for wireless communication performable at a wireless station (STA) including:
  • a wireless access point AP transmitting, to a wireless access point (AP) , a first frame including an indication that the STA has data to transmit, an indication of a size associated with the data, and an indication of a transmission time associated with transmitting the data in accordance with a latency constraint;
  • AP wireless access point
  • a trigger frame that includes a resource allocation identifying one or more resource units associated with the size for transmitting the data
  • a second frame including an indication that the STA has the data to transmit, an indication of the size associated with the data, and an indication of an updated time window indicating the duration in which the data is allowed to remain queued at the STA prior to the transmission time in accordance with the latency constraint.

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  • Engineering & Computer Science (AREA)
  • Quality & Reliability (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Mobile Radio Communication Systems (AREA)

Abstract

La présente divulgation concerne des procédés, des composants, des dispositifs et des systèmes destinés à utiliser des techniques de service à faible latence pour prendre en charge un service à faible latence limitée pour une transmission de paquets vers l'amont basée sur les événements. Une station (STA) peut avoir un grand paquet qui nécessite une transmission à faible latence. Pour faciliter la transmission du paquet, la STA peut transmettre une indication à l'AP avant un instant associé à une contrainte de latence du paquet. Dans l'indication, la STA peut inclure la taille associée au paquet ainsi qu'un instant d'émission estimé du paquet. Lors de la réception de l'indication, l'AP peut déterminer une unité de ressource (RU) appropriée, sur la base, au moins en partie, de la taille du paquet fournie dans l'indication. L'AP peut transmettre une trame de déclenchement qui comprend une allocation de ressources comportant l'unité de ressource. En conséquence, la STA peut utiliser l'unité de ressource pour transmettre le paquet, garantissant un temps de propagation limité.
PCT/CN2023/120312 2023-09-21 2023-09-21 Techniques de service à faible latence pour transmission de paquets Pending WO2025059971A1 (fr)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20180310338A1 (en) * 2015-12-25 2018-10-25 Huawei Technologies Co., Ltd. Access Method And Apparatus
US20200404683A1 (en) * 2019-06-21 2020-12-24 Qualcomm Incorporated Selective adjustment of packet durations
US20220150761A1 (en) * 2019-03-25 2022-05-12 Lg Electronics Inc. Method and device for performing low latency communication in wireless lan system
WO2022238155A1 (fr) * 2021-05-10 2022-11-17 Canon Kabushiki Kaisha Procédés de communication et appareil multi-liaisons

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20180310338A1 (en) * 2015-12-25 2018-10-25 Huawei Technologies Co., Ltd. Access Method And Apparatus
US20220150761A1 (en) * 2019-03-25 2022-05-12 Lg Electronics Inc. Method and device for performing low latency communication in wireless lan system
US20200404683A1 (en) * 2019-06-21 2020-12-24 Qualcomm Incorporated Selective adjustment of packet durations
WO2022238155A1 (fr) * 2021-05-10 2022-11-17 Canon Kabushiki Kaisha Procédés de communication et appareil multi-liaisons

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