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WO2025230775A1 - Signalisation pour permettre une préemption d'opportunité de transmission (txop) d'ensemble de services de base se chevauchant (obss) - Google Patents

Signalisation pour permettre une préemption d'opportunité de transmission (txop) d'ensemble de services de base se chevauchant (obss)

Info

Publication number
WO2025230775A1
WO2025230775A1 PCT/US2025/025820 US2025025820W WO2025230775A1 WO 2025230775 A1 WO2025230775 A1 WO 2025230775A1 US 2025025820 W US2025025820 W US 2025025820W WO 2025230775 A1 WO2025230775 A1 WO 2025230775A1
Authority
WO
WIPO (PCT)
Prior art keywords
txop
frame
sharing
control frame
ifs
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.)
Pending
Application number
PCT/US2025/025820
Other languages
English (en)
Inventor
Si-Chan NOH
Joonsoo Lee
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Newracom Inc
Original Assignee
Newracom Inc
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Newracom Inc filed Critical Newracom Inc
Publication of WO2025230775A1 publication Critical patent/WO2025230775A1/fr
Pending legal-status Critical Current
Anticipated expiration legal-status Critical

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00—Arrangements affording multiple use of the transmission path
    • H04L5/0091—Signalling for the administration of the divided path, e.g. signalling of configuration information
    • H04L5/0094—Indication of how sub-channels of the path are allocated
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00—Arrangements affording multiple use of the transmission path
    • H04L5/003—Arrangements for allocating sub-channels of the transmission path
    • H04L5/0044—Allocation of payload; Allocation of data channels, e.g. PDSCH or PUSCH
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W72/00—Local resource management
    • H04W72/04—Wireless resource allocation
    • H04W72/044—Wireless resource allocation based on the type of the allocated resource
    • H04W72/0446—Resources in time domain, e.g. slots or frames
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W74/00—Wireless channel access
    • H04W74/08—Non-scheduled access, e.g. ALOHA
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W28/00—Network traffic management; Network resource management
    • H04W28/02—Traffic management, e.g. flow control or congestion control

Definitions

  • the present disclosure generally relates to wireless communications, and more specifically, relates to signaling to allow overlapping basic service set (OBSS) transmission opportunity (TXOP) preemption.
  • OBSS overlapping basic service set
  • TXOP transmission opportunity
  • Institute of Electrical and Electronics Engineers (IEEE) 802.11 is a set of standards for implementing wireless local area network communication in various frequencies, including but not limited to the 2.4 gigahertz (GHz), 5 GHz, 6 GHz, and 60 GHz bands. These standards define the protocols that enable Wi-Fi devices to communicate with each other.
  • the IEEE 802.11 family of standards has evolved over time to accommodate higher data rates, improved security, and better performance in different environments. Some of the most widely used standards include 802.11a, 802.11b, 802.11g, 802.1 In, 802.1 lac, and 802.1 lax (also known as “Wi-Fi 6”). These standards specify the modulation techniques, channel bandwidths, and other technical aspects that facilitate interoperability between devices from various manufacturers. IEEE 802.11 has played an important role in the widespread adoption of wireless networking in homes, offices, and public spaces, enabling users to connect their devices to the internet and each other without the need for wired connections.
  • IEEE 802.1 Ibe also known as “Wi-Fi 7” is the next generation of the IEEE 802.11 family of standards for wireless local area networks.
  • 802.1 Ibe aims to significantly improve upon the capabilities of its predecessor, 802.1 lax/Wi-Fi 6, by offering even higher data rates, lower latency, and increased reliability.
  • MLO multi-link operation
  • 802. l lbe will introduce 4096-QAM (Quadrature Amplitude Modulation), enabling higher data rates by encoding more bits per symbol.
  • the standard will also feature improved medium access control (MAC) efficiency, enhanced power saving capabilities, and better support for high-density environments.
  • MAC medium access control
  • 802.1 Ibe is expected to deliver theoretical maximum data rates of up to 46 gigabits per second (Gbps), making it suitable for bandwidth-intensive applications such as virtual and augmented reality, 8K video streaming, and high-performance gaming.
  • Gbps gigabits per second
  • the IEEE 802.1 Ibe standard is projected to be finalized by the end of 2024, paving the way for the next generation of Wi-Fi devices and networks.
  • LL traffic is traffic that needs to be transmitted with low latency (e.g., urgent traffic).
  • LL traffic can be categorized into two types: periodic LL traffic and aperiodic (i.e., event-based) LL traffic.
  • a multi-access point (AP) coordination scheme that divides/ shares resource between APs (e.g., coordinated spatial reuse (C-SR), coordinated time division multiple access (C-TDMA), coordinated orthogonal frequency division multiple access (C-OFDMA), etc.) can be used to support periodic LL traffic.
  • C-SR coordinated spatial reuse
  • C-TDMA coordinated time division multiple access
  • C-OFDMA coordinated orthogonal frequency division multiple access
  • a preemption scheme can be used to support periodic LL traffic or aperiodic LL traffic.
  • a preemption scheme may allow devices, including the transmission opportunity (TXOP) holder, to preempt the TXOP holder’s ongoing TXOP to support LL traffic.
  • Existing preemption schemes are designed for a single basic service set (BSS) scenario (e.g., to support DL/UL (downlink/uplink) LL traffic during an UL/DL (uplink/downlink) TXOP).
  • BSS basic service set
  • the downlink TXOP may be preempted to support uplink (UL) LL traffic.
  • the uplink TXOP may be preempted to support downlink (DL) LL traffic.
  • OBSS overlapping BSS
  • STAs non-AP stations
  • FIG. 1 illustrates an example of a wireless local area network (WLAN) with a basic service set (BSS) that includes multiple wireless devices, in accordance with some embodiments of the present disclosure.
  • WLAN wireless local area network
  • BSS basic service set
  • Figure 2 is a schematic diagram of a wireless device, in accordance with some embodiments of the present disclosure.
  • Figure 3A illustrates components of a wireless device configured to transmit data, in accordance with some embodiments of the present disclosure.
  • Figure 3B illustrates components of a wireless device configured to receive data, in accordance with some embodiments of the present disclosure.
  • FIG 4 illustrates interframe space (IFS) relationships, in accordance with some embodiments of the present disclosure.
  • Figure 5 illustrates a Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA)-based frame transmission procedure, in accordance with some embodiments of the present disclosure.
  • CSMA/CA Carrier Sense Multiple Access with Collision Avoidance
  • FIG. 6 illustrates maximum physical layer (PHY) rates for Institute of Electrical and Electronics Engineers (IEEE) 802.11 standards, in accordance with some embodiments of the present disclosure.
  • PHY physical layer
  • FIG. 7 provides a detailed description of fields in Extremely High Throughput (EHT) Physical Protocol Data Unit (PPDU) frames, including their purposes and characteristics, in accordance with some embodiments of the present disclosure.
  • EHT Extremely High Throughput
  • PPDU Physical Protocol Data Unit
  • Figure 8 illustrates an example of multi-user (MU) transmission in Orthogonal Frequency-Division Multiple Access (OFDMA), in accordance with some embodiments of the present disclosure.
  • MU multi-user
  • OFDMA Orthogonal Frequency-Division Multiple Access
  • Figure 9 illustrates an example of an access point sending a trigger frame to multiple associated stations and receiving Uplink Orthogonal Frequency-Division Multiple Access Trigger-Based Physical Protocol Data Units (UL OFDMA TB PPDUs) in response, in accordance with some embodiments of the present disclosure.
  • UL OFDMA TB PPDUs Uplink Orthogonal Frequency-Division Multiple Access Trigger-Based Physical Protocol Data Units
  • Figure 13 is a flow diagram of a method for allowing a TXOP to be preempted, according to some embodiments.
  • Figure 14 is a flow diagram of a method for preempting a TXOP, according to some embodiments.
  • the present disclosure generally relates to wireless communications, and more specifically, relates to signaling to allow overlapping basic service set (OBSS) transmission opportunity (TXOP) preemption.
  • OBSS overlapping basic service set
  • TXOP transmission opportunity
  • OBSS devices e.g., access points (APs) and/or non-AP stations (STAs) that belong to an OBSS with respect to the transmission opportunity (TXOP) holder.
  • APs access points
  • STAs non-AP stations
  • the present disclosure introduces an OBSS TXOP preemption technique that allows OBSS devices to preempt a TXOP.
  • the OBSS TXOP preemption technique described herein may be able to support low latency traffic that occurs at OBSS devices before the end of the current TXOP holder’s TXOP.
  • a sharing AP that holds a TXOP may transmit a control frame to invite any non-TXOP holder APs within its coverage area to request preemption of the sharing AP’s TXOP.
  • a sharing AP may be an AP that is willing to share a TXOP held by the AP with other APs. Any non-TXOP holder APs that receive the control frame may transmit a response frame to the sharing AP as a response to the control frame (e.g., after a short interframe space (SIFS) interval after receiving the control frame) if the non-TXOP holder AP wishes to preempt the sharing AP’s TXOP.
  • SIFS short interframe space
  • the sharing AP may determine whether a response frame was received from at least one non-TXOP holder AP as a response to the control frame. If the sharing AP determines that it has received a response frame from at least one non-TXOP holder AP, the sharing AP may refrain from transmitting in the sharing AP’s BSS to allow the sharing AP’s TXOP to be preempted. Also, after transmitting the response frame, the non-TXOP holder APs that transmitted a response frame may participate in a channel contention mechanism to try to acquire the channel. The non-TXOP holder AP that is able to acquire the channel may transmit traffic in its own BSS, thereby preempting the sharing AP’s TXOP.
  • the sharing AP may assume that there are no non-TXOP holder APs that wish to preempt the TXOP and maintain its TXOP by resuming/continuing transmission in the sharing AP’s BSS.
  • PIFS point coordination function interframe space
  • a sharing AP may transmit a control frame to give non-TXOP holder APs an opportunity to preempt the sharing AP’s TXOP, if so desired.
  • Non-TXOP holder APs that receive the control frame from the sharing AP and that wish to preempt the sharing AP’s TXOP may transmit response frames and participate in a channel contention mechanism.
  • the non-TXOP holder AP that is able to acquire the channel after participating in the channel contention mechanism may preempt the sharing AP’s TXOP.
  • the OBSS TXOP preemption technique described herein may be used to support low latency traffic that may occur in OBSSs (BSSs operated by non-TXOP holder APs) without having to wait until the end of the sharing AP’s TXOP.
  • FIG. 1 shows a wireless local area network (WLAN) 100 with a basic service set (BSS) 102 that includes a plurality of wireless devices 104 (sometimes referred to as WLAN devices 104).
  • WLAN devices 104 may include a medium access control (MAC) layer and a physical (PHY) layer according to an IEEE (Institute of Electrical and Electronics Engineers) standard 802.11, including one or more of the amendments
  • the MAC layer of a wireless device 104 may initiate transmission of a frame to another wireless device 104 by passing a PHY- TXSTART. request (TXVECTOR) to the PHY layer.
  • TXVECTOR provides parameters for generating and/or transmitting a corresponding frame.
  • a PHY layer of a receiving wireless device may generate an RXVECTOR, which includes parameters of a received frame and is passed to a MAC layer for processing.
  • the plurality of wireless devices 104 may include a wireless device 104A that is an access point (sometimes referred to as an AP station or AP STA) and the other wireless devices 104B1-104B4 that are non-AP stations (sometimes referred to as non-AP STAs). Alternatively, all the plurality of wireless devices 104 may be non-AP STAs in an ad-hoc networking environment. In general, the AP STA (e.g., wireless device 104A) and the non-AP STAs (e.g., wireless devices 104B1-104B4) may be collectively referred to as STAs. However, for ease of description, only the non-AP STAs may be referred to as STAs unless the context indicates otherwise. Although shown with four non-AP STAs (e.g., the wireless devices 104B1- 104B4), the WLAN 100 may include any number of non-AP STAs (e.g., one or more wireless devices 104B).
  • FIG. 2 illustrates a schematic block diagram of a wireless device 104, according to an embodiment.
  • the wireless device 104 may be the wireless device 104A (i.e., the AP of the WLAN 100) or any of the wireless devices 104B1-104B4 in Figure 1.
  • the wireless device 104 includes a baseband processor 210, a radio frequency (RF) transceiver 240, an antenna unit 250, a storage device (e.g., memory device) 232, one or more input interfaces 234, and one or more output interfaces 236.
  • the baseband processor 210, the storage device 232, the input interfaces 234, the output interfaces 236, and the RF transceiver 240 may communicate with each other via a bus 260.
  • the baseband processor 210 performs baseband signal processing and includes a MAC processor 212 and a PHY processor 222.
  • the baseband processor 210 may utilize the memory 232, which may include a non-transitory computer/machine readable medium having software (e.g., computer/machine programing instructions) and data stored therein.
  • the MAC processor 212 includes a MAC software processing unit 214 and a MAC hardware processing unit 216.
  • the MAC software processing unit 214 may implement a first plurality of functions of the MAC layer by executing MAC software, which may be included in the software stored in the storage device 232.
  • the MAC hardware processing unit 216 may implement a second plurality of functions of the MAC layer in specialpurpose hardware.
  • the MAC processor 212 is not limited thereto.
  • the MAC processor 212 may be configured to perform the first and second plurality of functions entirely in software or entirely in hardware according to an implementation.
  • the PHY processor 222 includes a transmitting (TX) signal processing unit (SPU) 224 and a receiving (RX) SPU 226.
  • the PHY processor 222 implements a plurality of functions of the PHY layer. These functions may be performed in software, hardware, or a combination thereof according to an implementation.
  • Functions performed by the transmitting SPU 224 may include one or more of Forward Error Correction (FEC) encoding, stream parsing into one or more spatial streams, diversity encoding of the spatial streams into a plurality of space-time streams, spatial mapping of the space-time streams to transmit chains, inverse Fourier Transform (iFT) computation, Cyclic Prefix (CP) insertion to create a Guard Interval (GI), and the like.
  • Functions performed by the receiving SPU 226 may include inverses of the functions performed by the transmitting SPU 224, such as GI removal, Fourier Transform computation, and the like.
  • the RF transceiver 240 includes an RF transmitter 242 and an RF receiver 244.
  • the RF transceiver 240 is configured to transmit first information received from the baseband processor 210 to the WLAN 100 (e.g., to another WLAN device 104 of the WLAN 100) and provide second information received from the WLAN 100 (e.g., from another WLAN device 104 of the WLAN 100) to the baseband processor 210.
  • the antenna unit 250 includes one or more antennas.
  • MIMO Multiple-Input Multiple- Output
  • MU-MIMO Multi-User MIMO
  • the antenna unit 250 may include a plurality of antennas.
  • the antennas in the antenna unit 250 may operate as a beam-formed antenna array.
  • the antennas in the antenna unit 250 may be directional antennas, which may be fixed or steerable.
  • the input interfaces 234 receive information from a user, and the output interfaces 236 output information to the user.
  • the input interfaces 234 may include one or more of a keyboard, keypad, mouse, touchscreen, microphone, and the like.
  • the output interfaces 236 may include one or more of a display device, touch screen, speaker, and the like.
  • WLAN device 104 may be implemented in either hardware or software. Which functions are implemented in software and which functions are implemented in hardware will vary according to constraints imposed on a design. The constraints may include one or more of design cost, manufacturing cost, time to market, power consumption, available semiconductor technology, etc.
  • FIG. 3 A illustrates components of a WLAN device 104 configured to transmit data according to an embodiment, including a transmitting (Tx) SPU (TxSP) 324, an RF transmitter 342, and an antenna 352.
  • Tx transmitting
  • TxSP transmitting SPU
  • RF transmitter 342 RF transmitter
  • antenna 352 the transmitting SPU 224, the RF transmitter 242, and an antenna of the antenna unit 250 of Figure 2, respectively.
  • the TxSP 324 includes an encoder 300, an interleaver 302, a mapper 304, an inverse Fourier transformer (IFT) 306, and a guard interval (GI) inserter 308.
  • IFT inverse Fourier transformer
  • GI guard interval
  • the encoder 300 receives and encodes input data.
  • the encoder 300 includes a forward error correction (FEC) encoder.
  • the FEC encoder may include a binary convolution code (BCC) encoder followed by a puncturing device.
  • the FEC encoder may include a low-density parity-check (LDPC) encoder.
  • the TxSP 324 may further include a scrambler for scrambling the input data before the encoding is performed by the encoder 300 to reduce the probability of long sequences of 0s or Is.
  • the TxSP 324 may further include an encoder parser for demultiplexing the scrambled bits among a plurality of BCC encoders. If LDPC encoding is used in the encoder, the TxSP 324 may not use the encoder parser.
  • the interleaver 302 interleaves the bits of each stream output from the encoder 300 to change an order of bits therein.
  • the interleaver 302 may apply the interleaving only when the encoder 300 performs BCC encoding and otherwise may output the stream output from the encoder 300 without changing the order of the bits therein.
  • the mapper 304 maps the sequence of bits output from the interleaver 302 to constellation points. If the encoder 300 performed LDPC encoding, the mapper 304 may also perform LDPC tone mapping in addition to constellation mapping.
  • the TxSP 324 may include a plurality of interleavers 302 and a plurality of mappers 304 according to a number of spatial streams (NSS) of the transmission.
  • the TxSP 324 may further include a stream parser for dividing the output of the encoder 300 into blocks and may respectively send the blocks to different interleavers 302 or mappers 304.
  • the TxSP 324 may further include a space-time block code (STBC) encoder for spreading the constellation points from the spatial streams into a number of space-time streams (NSTS) and a spatial mapper for mapping the space-time streams to transmit chains.
  • STBC space-time block code
  • the spatial mapper may use direct mapping, spatial expansion, or beamforming.
  • the IFT 306 converts a block of the constellation points output from the mapper 304 (or, when MIMO or MU-MIMO is performed, the spatial mapper) to a time domain block (i.e., a symbol) by using an inverse discrete Fourier transform (IDFT) or an inverse fast Fourier transform (IFFT). If the STBC encoder and the spatial mapper are used, the IFT 306 may be provided for each transmit chain.
  • IDFT inverse discrete Fourier transform
  • IFFT inverse fast Fourier transform
  • the TxSP 324 may insert cyclic shift diversities (CSDs) to prevent unintentional beamforming.
  • CSDs cyclic shift diversities
  • the TxSP 324 may perform the insertion of the CSD before or after the IFT 306.
  • the CSD may be specified per transmit chain or may be specified per space-time stream. Alternatively, the CSD may be applied as a part of the spatial mapper.
  • the TxSP 324 performs a MIMO or MU-MIMO transmission, some blocks before the spatial mapper may be provided for each user.
  • the GI inserter 308 prepends a GI to each symbol produced by the IFT 306.
  • Each GI may include a Cyclic Prefix (CP) corresponding to a repeated portion of the end of the symbol that the GI precedes.
  • the TxSP 324 may optionally perform windowing to smooth edges of each symbol after inserting the GI.
  • the RF transmitter 342 converts the symbols into an RF signal and transmits the RF signal via the antenna 352.
  • the TxSP 324 performs a MIMO or MU-MIMO transmission
  • the GI inserter 308 and the RF transmitter 342 may be provided for each transmit chain.
  • FIG. 3B illustrates components of a WLAN device 104 configured to receive data according to an embodiment, including a Receiver (Rx) SPU (RxSP) 326, an RF receiver 344, and an antenna 354.
  • Rx Receiver
  • RxSP Receiver
  • RF receiver 344 RF receiver 344
  • antenna 354 the RxSP 326, RF receiver 344, and antenna 354 may correspond to the receiving SPU 226, the RF receiver 244, and an antenna of the antenna unit 250 of Figure 2, respectively.
  • the RxSP 326 includes a GI remover 318, a Fourier transformer (FT) 316, a demapper 314, a deinterleaver 312, and a decoder 310.
  • FT Fourier transformer
  • the RF receiver 344 receives an RF signal via the antenna 354 and converts the RF signal into symbols.
  • the GI remover 318 removes the GI from each of the symbols.
  • the RF receiver 344 and the GI remover 318 may be provided for each receive chain.
  • the FT 316 converts each symbol (that is, each time domain block) into a frequency domain block of constellation points by using a discrete Fourier transform (DFT) or a fast Fourier transform (FFT).
  • DFT discrete Fourier transform
  • FFT fast Fourier transform
  • the FT 316 may be provided for each receive chain.
  • the RxSP 326 may include a spatial demapper for converting the respective outputs of the FTs 316 of the receiver chains to constellation points of a plurality of space-time streams, and an STBC decoder for despreading the constellation points from the space-time streams into one or more spatial streams.
  • the demapper 314 demaps the constellation points output from the FT 316 or the STBC decoder to bit streams. If the received transmission was encoded using LDPC encoding, the demapper 314 may further perform LDPC tone demapping before performing the constellation demapping.
  • the deinterleaver 312 deinterleaves the bits of each stream output from the demapper 314.
  • the deinterleaver 312 may perform the deinterleaving only when the received transmission was encoded using BCC encoding, and otherwise may output the stream output by the demapper 314 without performing deinterleaving.
  • the received transmission is the MIMO or MU-MIMO transmission
  • RxSP 326 may use a plurality of demappers 314 and a plurality of deinterleavers 312 corresponding to the number of spatial streams of the transmission.
  • the RxSP 326 may further include a stream deparser for combining the streams output from the deinterleavers 312.
  • the decoder 310 decodes the streams output from the deinterleaver 312 or the stream deparser.
  • the decoder 310 includes an FEC decoder.
  • the FEC decoder may include a BCC decoder or an LDPC decoder.
  • the RxSP 326 may further include a descrambler for descrambling the decoded data.
  • the RxSP 326 may further include an encoder deparser for multiplexing the data decoded by a plurality of BCC decoders.
  • the RxSP 326 may not use the encoder deparser.
  • wireless devices such as wireless device 104 will assess the availability of the wireless medium using Clear Channel Assessment (CCA). If the medium is occupied, CCA may determine that it is busy, while if the medium is available, CCA determines that it is idle.
  • CCA Clear Channel Assessment
  • the PHY entity for IEEE 802.11 is based on Orthogonal Frequency Division Multiplexing (OFDM) or Orthogonal Frequency Division Multiple Access (OFDMA).
  • OFDM Orthogonal Frequency Division Multiplexing
  • OFDMA Orthogonal Frequency Division Multiple Access
  • a STA e.g., a wireless device 10
  • PHY Physical Layer
  • PPDUs Physical Layer
  • PLCP Physical Layer Convergence Procedure
  • a PHY specification defines a set of Modulation and Coding Schemes (MCS) and a maximum number of spatial streams.
  • Some PHY entities define downlink (DL) and uplink (UL) Multi-User (MU) transmissions having a maximum number of space-time streams (STS) per user and employing up to a predetermined total number of STSs.
  • a PHY entity may provide support for 10 Megahertz (MHz), 20 MHz, 40 MHz, 80 MHz, 160 MHz, 240 MHz, and 320 MHz contiguous channel widths and support for an 80+80, 80+160 MHz, and 160+160 MHz non-contiguous channel width.
  • Each channel includes a plurality of subcarriers, which may also be referred to as tones.
  • a PHY entity may define signaling fields denoted as Legacy Signal (L-SIG), Signal A (SIG-A), and Signal B (SIG-B), and the like within a PPDU by which some necessary information about PHY Service Data Unit (PSDU) attributes are communicated.
  • L-SIG Legacy Signal
  • SIG-A Signal A
  • SIG-B Signal B
  • PSDU PHY Service Data Unit
  • Figure 4 illustrates Inter-Frame Space (IFS) relationships.
  • IFS Inter-Frame Space
  • Figure 4 illustrates a Short IFS (SIFS), a Point Coordination Function (PCF) IFS (PIFS), a Distributed Coordination Function (DCF) IFS (DIFS), and an Arbitration IFSs corresponding to an Access Category (AC) ‘i’ (AIF S [i]).
  • SIFS Short IFS
  • PCF Point Coordination Function
  • DCF Distributed Coordination Function
  • AC Access Category
  • Figure 4 also illustrates a slot time and a data frame is used for transmission of data forwarded to a higher layer.
  • a WLAN device 104 transmits the data frame after performing backoff if a DIFS has elapsed during which the medium has been idle.
  • a management frame may be used for exchanging management information, which is not forwarded to the higher layer.
  • Subtype frames of the management frame include a beacon frame, an association request/response frame, a probe request/response frame, and an authentication request/response frame.
  • a control frame may be used for controlling access to the medium.
  • Subtype frames of the control frame include a request to send (RTS) frame, a clear to send (CTS) frame, and an acknowledgement (ACK) frame.
  • RTS request to send
  • CTS clear to send
  • ACK acknowledgement
  • the WLAN device 104 transmits the control frame after performing backoff if a DIFS has elapsed during which the medium has been idle.
  • the control frame is the response frame of another frame
  • the WLAN device 104 transmits the control frame after a SIFS has elapsed without performing backoff or checking whether the medium is idle.
  • a WLAN device 104 that supports Quality of Service (QoS) functionality may transmit the frame after performing backoff if an AIFS for an associated access category (AC) (i.e., AIFS[AC]) has elapsed.
  • QoS Quality of Service
  • AC access category
  • any of the data frame, the management frame, and the control frame, which is not the response frame may use the AIFS [AC] of the AC of the transmitted frame.
  • a WLAN device 104 may perform a backoff procedure when the WLAN device 104 that is ready to transfer a frame finds the medium busy.
  • the backoff procedure includes determining a random backoff time composed of N backoff slots, where each backoff slot has a duration equal to a slot time and N being an integer number greater than or equal to zero.
  • the backoff time may be determined according to a length of a Contention Window (CW). In an embodiment, the backoff time may be determined according to an AC of the frame. All backoff slots occur following a DIFS or Extended IFS (EIFS) period during which the medium is determined to be idle for the duration of the period.
  • DIFS DIFS
  • EIFS Extended IFS
  • the backoff procedure shall decrement the backoff time by the slot time.
  • the backoff procedure is suspended until the medium is again determined to be idle for the duration of a DIFS or EIFS period.
  • the WLAN device 104 may perform transmission or retransmission of the frame when the backoff timer reaches zero.
  • the backoff procedure operates so that when multiple WLAN devices 104 are deferring and execute the backoff procedure, each WLAN device 104 may select a backoff time using a random function and the WLAN device 104 that selects the smallest backoff time may win the contention, reducing the probability of a collision.
  • Figure 5 illustrates a Carrier Sense Multiple Access/Collision Avoidance (CSMA/CA) based frame transmission procedure for avoiding collision between frames in a channel according to an embodiment.
  • Figure 5 shows a first station STA1 transmitting data, a second station STA2 receiving the data, and a third station STA3 that may be located in an area where a frame transmitted from the STA1 can be received, a frame transmitted from the second station STA2 can be received, or both can be received.
  • the stations STA1, STA2, and STA3 may be WLAN devices 104 of Figure 1.
  • the station STA1 may determine whether the channel is busy by carrier sensing.
  • the station STA1 may determine channel occupation/status based on an energy level in the channel or an autocorrelation of signals in the channel, or may determine the channel occupation by using a network allocation vector (NAV) timer.
  • NAV network allocation vector
  • the station STA1 may transmit a Request-To-Send (RTS) frame to the station STA2.
  • RTS Request-To-Send
  • the station STA2 may transmit a Clear-To-Send (CTS) frame as a response to the RTS frame.
  • CTS Clear-To-Send
  • the AP may send two CTS frames in response to the RTS frame (e.g., a first CTS frame in a non-High Throughput format and a second CTS frame in the HT format).
  • the station STA3 may set a NAV timer of the station STA3 for a transmission duration of subsequently transmitted frames (for example, a duration of SIFS + CTS frame duration + SIFS + data frame duration + SIFS + ACK frame duration) using duration information included in the RTS frame.
  • a NAV timer of the station STA3 for a transmission duration of subsequently transmitted frames using duration information included in the CTS frame.
  • the station STA3 may update the NAV timer of the station STA3 by using duration information included in the new frame. The station STA3 does not attempt to access the channel until the NAV timer expires.
  • the station STA1 When the station STA1 receives the CTS frame from the station STA2, it may transmit a data frame to the station STA2 after a SIFS period elapses from a time when the CTS frame has been completely received. Upon successfully receiving the data frame, the station STA2 may transmit an ACK frame as a response to the data frame after a SIFS period elapses.
  • the third station STA3 may determine whether the channel is busy using the carrier sensing. Upon determining that the channel is not used by other devices during a DIFS period after the NAV timer has expired, the station STA3 may attempt to access the channel after a contention window elapses according to a backoff process.
  • a station that has obtained a transmission opportunity (TXOP) and that has no data to transmit may transmit a CF-End frame to cut short the TXOP.
  • TXOP transmission opportunity
  • An AP receiving a CF-End frame having a Basic Service Set Identifier (BSSID) of the AP as a destination address may respond by transmitting two more CF-End frames: a first CF-End frame using Space Time Block Coding (STBC) and a second CF-End frame using non-STBC.
  • a station receiving a CF-End frame resets its NAV timer to 0 at the end of the PPDU containing the CF-End frame.
  • Figure 5 shows the station STA2 transmitting an ACK frame to acknowledge the successful reception of a frame by the recipient.
  • the IEEE 802.1 Ibn (Ultra High Reliability, UHR) working group has been established to address the growing demand for higher peak throughput and reliability in Wi-Fi.
  • the peak PHY rate has significantly increased from IEEE 802.1 lb to IEEE 802.1 Ibe (Wi-Fi 7), with the latter focusing on further improving peak throughput.
  • the UHR study group aims to enhance the tail of the latency distribution and jitter to support applications that require low latency, such as video-over- WLAN, gaming, AR, and VR. It is noted that various characteristics of UHR (e.g., max PHY rate, PHY rate enhancement, bandwidth/number of spatial streams, and operating bands) are still to be determined.
  • the focus of IEEE 802.1 Ibe is primarily on WLAN indoor and outdoor operation with stationary and pedestrian speeds in the 2.4, 5, and 6 GHz frequency bands.
  • candidate features include (1) a 320MHz bandwidth and a more efficient utilization of a non-contiguous spectrum, (2) multi -band/multi-channel aggregation and operation, (3) 16 spatial streams and Multiple Input Multiple Output (MIMO) protocol enhancements, (4) multi-Access Point (AP) Coordination (e.g., coordinated and joint transmission), (5) an enhanced link adaptation and retransmission protocol (e.g., Hybrid Automatic Repeat Request (HARQ)), and (6) adaptation to regulatory rules specific to a 6 GHz spectrum.
  • MIMO Multiple Input Multiple Output
  • MLO enhancements e.g., in terms of increased throughput/reliability and decreased latency
  • latency and reliability improvements e.g., multi-AP coordination to support low latency traffic
  • bandwidth expansion e.g., to 240, 480, 640 MHz
  • aggregated PPDU A- PPDU
  • eMLSR enhanced multi-link single-radio
  • a transmitting station creates a Physical Layer Protocol Data Unit (PPDU) frame and sends it to a receiving STA.
  • the receiving STA then receives, detects, and processes the PPDU.
  • PPDU Physical Layer Protocol Data Unit
  • the Extremely High Throughput (EHT) PPDU frame encompasses several components. It includes a legacy part, which comprises fields such as the Legacy Short Training Field (L-STF), Legacy Long Training Field (L-LTF), Legacy Signal Field (L-SIG), and Repeated Legacy Signal Field (RL-SIG). These fields are used to maintain compatibility with older Wi-Fi standards.
  • L-STF Legacy Short Training Field
  • L-LTF Legacy Long Training Field
  • L-SIG Legacy Signal Field
  • RL-SIG Repeated Legacy Signal Field
  • the EHT PPDU frame also contains the Universal Signal Field (U-SIG), EHT Signal Field (EHT-SIG), EHT Short Training Field (EHT-STF), and EHT Long Training Field (EHT-LTF). These fields are specific to the EHT standard and are used for various purposes, such as signaling, synchronization, and channel estimation.
  • U-SIG Universal Signal Field
  • EHT-SIG EHT Signal Field
  • EHT-STF EHT Short Training Field
  • EHT-LTF EHT Long Training Field
  • Figure 7 provides a more detailed description of each field in the EHT PPDU frame, including their purposes and characteristics.
  • UHR Ultra High Reliability
  • BSS basic service set
  • UL uplink
  • DL downlink
  • MU multi-user
  • MU transmission refers to situations where multiple frames are transmitted to or from multiple STAs simultaneously using different resources.
  • these resources include different frequency resources in Orthogonal Frequency Division Multiple Access (OFDMA) transmission and different spatial streams in Multi-User Multiple Input Multiple Output (MU-MIMO) transmission. Consequently, downlink OFDMA (DL-OFDMA), downlink MU-MIMO (DL-MU-MIMO), uplink OFDMA (UL-OFDMA), uplink MU-MIMO (UL-MU-MIMO), and OFDMA with MU-MIMO are all considered examples of MU transmission.
  • Figure 8 illustrates an example of multi-user (MU) transmission in Orthogonal Frequency-Division Multiple Access (OFDMA), in accordance with some embodiments of the present disclosure.
  • the trigger frame plays a useful role in facilitating uplink multi-user (MU) transmissions.
  • the purpose of the trigger frame is to allocate resources and solicit one or more Trigger-based (TB) Physical Layer Protocol Data Unit (PPDU) transmissions from the associated stations (STAs).
  • TB Trigger-based
  • PPDU Physical Layer Protocol Data Unit
  • the trigger frame contains information required by the responding STAs to send their Uplink TB PPDUs. This information includes the Trigger type, which specifies the type of TB PPDU expected, and the Uplink Length (UL Length), which indicates the duration of the uplink transmission.
  • Trigger type which specifies the type of TB PPDU expected
  • UL Length Uplink Length
  • FIG. 9 illustrates an example scenario where an access point (AP) operating in an 80MHz bandwidth environment sends a Trigger frame to multiple associated STAs.
  • the STAs Upon receiving the Trigger frame, the STAs respond by sending their respective Uplink Orthogonal Frequency Division Multiple Access (UL OFDMA) TB PPDUs, utilizing the allocated resources within the specified 80 MHz bandwidth.
  • U OFDMA Uplink Orthogonal Frequency Division Multiple Access
  • the AP After successfully receiving the UL OFDMA TB PPDUs, the AP acknowledges the STAs by sending an acknowledgement frame.
  • This acknowledgement can be in the form of an 80MHz width multi-STA Block Acknowledgement (Block Ack) or a Block Acknowledgement with a Direct Feedback (DF) OFDMA method.
  • Block Ack multi-STA Block Acknowledgement
  • DF Direct Feedback
  • the multi-STA Block Ack allows the AP to acknowledge multiple STAs simultaneously, while the Block Ack with DF OFDMA enables the AP to provide feedback to the STAs using the same OFDMA technique employed in the uplink transmission.
  • the trigger frame is a useful component in enabling efficient uplink MU transmissions in IEEE 802.1 lax and 802.1 Ibe networks, by allocating resources and coordinating the uplink transmissions from multiple STAs within the same bandwidth.
  • Wireless network systems can rely on retransmission of media access control (MAC) protocol data units (MPDUs) when the transmitter (TX) does not receive an acknowledgement from the receiver (RX) or MPDUs are not successfully decoded by the receiver.
  • MAC media access control
  • MPDUs protocol data units
  • ARQ automatic repeat request
  • the receiver discards the last failed MPDU before receiving the newly retransmitted MPDU.
  • HARQ hybrid ARQ
  • CC-HARQ chase combining
  • FEC forward error correction
  • MRC maximum-ratio combining
  • the receiver uses both the current and the previously received subpackets for decoding data, the error probability in decoding decreases as the number of used subpackets increases.
  • the decoding process passes a cyclic redundancy check (CRC) and ends when the entire packet is decoded without error or the maximum number of subpackets is reached.
  • CRC cyclic redundancy check
  • this scheme operates on a stop-and-wait protocol such that if the receiver can decode the packet, it sends an acknowledgement (ACK) to the transmitter.
  • ACK acknowledgement
  • the transmitter receives an ACK successfully, it terminates the HARQ transmission of the packet. If the receiver cannot decode the packet, it sends a negative acknowledgement (NAK) to the transmitter and the transmitter performs the retransmission process.
  • NAK negative acknowledgement
  • a second type of HARQ scheme also referred to as an incremental redundancy (IR) HARQ (IR-HARQ) scheme
  • IR-HARQ incremental redundancy HARQ
  • different puncturing patterns are used for each subpacket such that the signal changes for each retransmitted subpacket in comparison to the originally transmitted subpacket.
  • IR-HARQ alternatively uses two puncturing patterns for odd numbered and even numbered transmissions, respectively.
  • the redundancy scheme of IR-HARQ improves the log likelihood ratio (LLR) of parity bit(s) in order to combine information sent across different transmissions due to requests and lowers the code rate as the additional subpacket is used. This results in a lower error rate of the subpacket in comparison to CC-HARQ.
  • LLR log likelihood ratio
  • the puncturing pattern used in IR-HARQ is indicated by a subpacket identity (SPID) indication.
  • SPID subpacket identity
  • the SPID of the first subpacket may always be set to 0 and all the systematic bits and the punctured parity bits are transmitted in the first subpacket.
  • Self-decoding is possible when the receiving signal- to-noise ratio (SNR) environment is good (i.e., a high SNR).
  • SNR signal- to-noise ratio
  • subpackets with corresponding SPIDs to be transmitted are in increasing order of SPID but can be exchanged/switched except for the first SPID.
  • AP coordination has been considered as a potential technology to improve WLAN system throughput in the IEEE 802.1 Ibe standard and is still being discussed in the IEEE 802.1 Ibn (UHR) standard.
  • AP coordination schemes such as coordinated beamforming, OFDMA, TDMA, spatial reuse, and joint transmission, a predefined mechanism for APs is necessary.
  • the AP that obtains a transmit opportunity (TXOP) is referred to as the sharing AP.
  • This AP initiates the AP coordination schemes to determine the AP candidate set by sending a frame, such as a Beacon frame or probe response frame, which includes information about the AP coordination scheme capabilities.
  • the AP that participates in the AP coordination schemes after receiving the frame from the sharing AP is called the shared AP.
  • the sharing AP is also known as the master AP or coordinating AP, while the shared AP is referred to as the slave AP or coordinated AP.
  • C-BF Coordinated Beamforming
  • C-OFDMA Coordinated OFDMA
  • JTX Joint Transmission
  • C-SR Coordinated Spatial Reuse
  • WLAN systems can improve their overall throughput and efficiency by leveraging the cooperation between multiple APs.
  • Figure 10 is a diagram showing a multi-BSS wireless network topology with multiple non-TXOP holder APs, according to some embodiments.
  • the multi-BSS wireless network may include a first AP (“API”), a second AP (“AP2”), a third AP (“AP3”), a first STA (“STA1”), a second STA (“STA2”), and a third STA (“STA3”).
  • API may operate a first BSS (“BSS1”)
  • AP2 may operate a second BSS (“BSS2”)
  • AP3 may operate a third BSS (“BSS3”).
  • BSS1 and BSS2 may be OBSSs with respect to each other (and vice versa).
  • BSS1 and BSS3 may be OBSSs with respect to each other (and vice versa).
  • STA1 may be associated with API and belong to BSS1.
  • STA2 may be associated with AP2 and belong to BSS2.
  • STA3 may be associated with AP3 and belong to BSS3.
  • API is the TXOP holder (and sharing AP) and that AP2 and AP3 are non-TXOP holder APs.
  • API may use its obtained TXOP without constraints.
  • API may request stream classification service (SCS) information from AP2 and AP3 when it becomes the TXOP holder.
  • AP2 and AP3 may provide SCS information to API.
  • the SCS information may include information regarding the quality of service (QoS) characteristics for time-sensitive network flows (e.g., indicating the urgency level of low latency traffic).
  • QoS quality of service
  • API may decide to allocate a portion of its obtained TXOP to AP2 and then to AP3 (in that order) based on the SCS information (e.g., if the SCS information indicates that AP2 has more urgent traffic to transmit than AP3).
  • API may decide to allocate a duration of “A” to AP2 (the TXOP sharing duration is “A”).
  • API may check whether there are any non-TXOP holder APs within its coverage area that have more urgent aperiodic low latency traffic to transmit.
  • API may accomplish this by transmitting a TXOP sharing (TXS) control frame that includes a preemption (PR) enabled indicator.
  • TXS TXOP sharing
  • PR preemption
  • Such frame may be referred to herein as a TXS(+PR) frame.
  • API may include an indication of TXOP sharing duration “A” in the TXOP sharing control frame.
  • the sharing AP may broadcast the TXOP sharing control frame.
  • Non-TXOP holder APs that receive the TXOP sharing control frame and that wish to preempt the sharing AP’s TXOP may transmit a preemption indicator frame to the sharing AP as a response to the TXOP sharing control frame and then participate in a channel contention mechanism to try to acquire the channel.
  • the non-TXOP that is able to acquire the channel after participating in the channel contention mechanism may start transmitting in its own BSS, thereby preempting the sharing AP’s TXOP.
  • the PR enabled indication included in the TXOP sharing control frame may have the function of indirectly asking whether a non-TXOP holder AP wishes to preempt the sharing AP’s TXOP. In this sense, the TXOP sharing control frame can be viewed as a “polling” frame that polls non-TXOP holder APs regarding their interest in preempting the sharing AP’s TXOP.
  • FIG 11 is a diagram showing a frame exchange sequence where multiple non- TXOP holder APs participate in a channel contention mechanism to preempt a sharing AP’s TXOP, according to some embodiments.
  • the frame exchange may involve API (which is a sharing AP in this example), AP2 (which is a non-TXOP holder AP in this example), AP3 (which is also a non-TXOP holder AP in this example), STA1 (which is associated with API), and STA3 (which is associated with AP3).
  • API may transmit a RTS frame 1105 to STA1 and STA1 may respond by transmitting a CTS frame 1110 to API.
  • API is the TXOP holder and sharing AP in this example.
  • API may transmit PPDU 1115 to STA1 and STA1 may respond by transmitting BA frame 1120 to API .
  • API may then transmit a TXS(+PR) frame 1125 as a broadcast frame.
  • the TXS(+PR) frame 1125 may be a TXOP sharing control frame that includes a preemption enabled indicator.
  • the preemption enabled indicator is included in the UHR SIG (ultra-high reliability signal) field included in the preamble of the TXS(+PR) frame 1125 (e.g., in a reserved field included in the UHR SIG field).
  • the preemption enabled indicator is included in an aggregated control (A-control) field included in the TXS(+PR) frame 1125 (e.g., within a new type of control field within an A-control field).
  • the preemption enabled indicator included in the TXS(+PR) frame 1125 may have the function of inviting any non-TXOP holder APs (e.g., AP2 and AP3) to transmit a preemption indicator frame if they wish to preempt API’s TXOP.
  • the TXS(+PR) frame 1125 may include an indication of a TXOP sharing duration (“allocated duration for preemption” shown in the diagram).
  • AP2 and AP3 may transmit preemption indicator frames to API if they wish to preempt API’s TXOP.
  • AP2 and AP3 wish to preempt API’s TXOP (e.g., because they have low latency traffic to transmit) so they each transmit a preemption indicator frame to sharing API as a response to the TXS(+PR) frame 1125.
  • AP2 may transmit preemption indicator (PRI) frame 1130 to API and AP3 may transmit preemption indicator frame 1135 to API.
  • PRI preemption indicator
  • Preemption indicator frame 1130 and preemption indicator frame 1135 may be transmitted simultaneously (e.g., be a MU transmission). Responsive to receiving the preemption indicator frames, API may refrain from resuming transmission in its own BSS (BSS1) to allow a non-TXOP holder AP to preempt the TXOP. After transmitting their respective preemption indicator frames, AP2 and AP3 may participate in a channel contention mechanism to try to acquire the channel. For example, AP2 and AP3 may perform an enhanced distributed channel access (EDCA) backoff procedure. The non-TXOP holder AP that is able to acquire the channel after participating in the channel contention mechanism may start transmitting traffic in its own BSS.
  • EDCA enhanced distributed channel access
  • AP3 may transmit PPDU 1140 (which may include low latency data) to STA3 (thereby preempting API’s TXOP) and STA3 may respond by transmitting BA frame 1145 to AP3 (in BSS3).
  • AP3 may determine the TXOP sharing duration (how long AP3 is allowed to preempt API’s TXOP for) based on information included in the TXS(+PR) frame 1125 and may utilize API’s TXOP for the TXOP sharing duration.
  • API may resume transmission in its own BSS (BSS1).
  • BSS1 BSS
  • API may transmit PPDU 1150 to STA1 and STA1 may respond by transmitting BA frame 1155 to API.
  • API determines the TXOP sharing duration based on SCS information (or other information regarding the urgency level of the traffic) of a non-TXOP holder AP. If API does not have SCS information of non-TXOP holder APs or otherwise does not have sufficient information regarding the traffic that non-TXOP holder APs wish to transmit, API may determine the TXOP sharing duration by itself.
  • API may maintain its TXOP (keep transmitting in its own BSS (BSS1)).
  • BSS1 BSS
  • FIG 12 is a diagram showing a frame exchange sequence where a sharing AP maintains its TXOP because it does not receive a preemption indicator frame from a non-TXOP holder AP, according to some embodiments.
  • the frame exchange may involve API (which is a sharing AP in this example), AP2 (which is a non-TXOP holder AP in this example), AP3 (which is also a non-TXOP holder AP in this example), STA1 (which is associated with API), and STA3 (which is associated with AP3).
  • API may transmit a RTS frame 1205 to STA1 and STA1 may respond by transmitting a CTS frame 1210 to API.
  • API is the TXOP holder and sharing AP in this example.
  • API may transmit PPDU 1215 to STA1 and STA1 may respond by transmitting BA frame 1220 to API.
  • API may then transmit a TXS(+PR) frame 1225 as a broadcast frame.
  • the preemption enabled indicator included in the TXS(+PR) frame 1125 may have the function of inviting any non-TXOP holder APs (e.g., AP2 and AP3) to transmit a preemption indicator frame if they wish to preempt API’s TXOP.
  • the TXS(+PR) frame 1125 may include an indication of TXOP sharing duration.
  • AP2 and AP3 may transmit preemption indicator frames to API after a short interframe space (SIFS) interval after receiving the TXS(+PR) frame 1225 if they wish to preempt API’s TXOP.
  • SIFS short interframe space
  • AP2 and AP3 do not wish to preempt API’s TXOP (e.g., because they do not have low latency traffic to transmit) so AP2 and AP3 do not transmit a preemption indicator frame.
  • API may recognize that there are no non-TXOP holder APs that wish to preempt the TXOP if it does not receive a preemption indicator frame within a SIFS interval after transmitting the TXS(+PR) frame 1225.
  • API may maintain its TXOP, for example, by transmitting PPDU 1230 to STA1 after a PIFS interval after transmitting the TXS(+PR) frame 1225.
  • STA1 may respond by transmitting BA frame 1235 to API.
  • API may continue utilizing the TXOP until the total TXOP duration acquired by API is over. For example, API may transmit PPDU 1240 to STA1 and STA1 may respond by transmitting BA frame 1245 to API, after which the total TXOP duration is over.
  • a sharing AP may transmit a control frame (e.g., TXS(+PR) frame) to give non-TXOP holder APs an opportunity to preempt the sharing AP’s TXOP, if so desired.
  • Non-TXOP holder APs that receive the control frame from the sharing AP and that wish to preempt the sharing AP’s TXOP may transmit a response frame (e.g., preemption indicator frame) after a first interframe space (IFS) interval after receiving the control frame and participate in a channel contention mechanism.
  • a response frame e.g., preemption indicator frame
  • the non-TXOP holder AP that is able to acquire the channel after participating in the channel contention mechanism may preempt the sharing AP’s TXOP by starting to transmit in its own BSS. If the sharing AP does not receive any response frames from non-TXOP holder APs, the sharing AP may maintain the sharing AP’s TXOP by starting to transmit in its own BSS after a second IFS interval after transmitting the control frame, where the second IFS interval is longer than the first IFS interval.
  • the first IFS interval may be a SIFS interval and the second IFS interval may be a PIFS interval, although it should be appreciated that other intervals/lengths can be used.
  • the OBSS TXOP preemption technique described herein may be used to support low latency traffic that may occur in OBSSs (BSSs operated by non-TXOP holder APs) without having to wait until the end of the sharing AP’s TXOP.
  • the control frame transmitted by the sharing AP may be viewed as frame that indicates the sharing AP’s intention to share its TXOP with a non-TXOP holder AP and that also “polls” non-TXOP holder APs regarding their interest in preempting the sharing AP’s TXOP.
  • Non-TXOP holder APs that receive the control frame may transmit a response frame to the sharing AP to indicate their desire to preempt the sharing AP’s TXOP.
  • the non-TXOP holder APs that transmit a response frame to the sharing AP may participate in a channel contention mechanism after transmitting their response frames to try to acquire the channel.
  • the non- TXOP holder AP that is able to acquire the channel may start transmitting in its own BSS, thereby preempting the sharing AP’s TXOP. If the sharing AP does not receive any response frames from non-TXOP holder APs, the sharing AP may assume that there are no non-TXOP holder APs that wish to preempt the sharing AP’s TXOP and resume transmitting in its own BSS.
  • the control frame is a TXOP sharing control frame (e.g., that includes a preemption enabled indicator) and the response frame is a preemption indicator frame.
  • the control frame is a polling announcement frame and the response frame is a multi-station block acknowledgement (M-BA) frame.
  • the method 1300 may be performed by a sharing AP.
  • the sharing AP may be implemented by a wireless device (e.g., wireless device 104).
  • the operations of the method 1300 may be performed in a different order.
  • the operations of the method 1300 are shown in a sequential order, some of the operations may be performed in partially or entirely overlapping time periods.
  • the sharing AP transmits a control frame.
  • the control frame includes a preemption enabled indicator (e.g., indicating the sharing AP’s intention to share its TXOP with a non-TXOP holder AP).
  • the preemption enabled indicator is included in a UHR-SIG field included in a preamble of the control frame.
  • the preemption enabled indicator is included in an A-control field included in the control frame.
  • the control frame is broadcasted (the control frame is a broadcasted frame).
  • the control frame includes an indication of a TXOP sharing duration.
  • the TXOP sharing duration is determined based on SCS information obtained from a non-TXOP holder AP.
  • the sharing AP determines whether a response frame was received from at least one non-TXOP holder AP. If a response frame was received from at least one non-TXOP holder AP, the method may proceed to operation 1320. Otherwise, if a response frame was not received from at least one non-TXOP holder AP, the method may proceed to operation 1315 at which the sharing AP starts to transmit in the sharing AP’s BSS.
  • the sharing AP starts to transmit in the sharing AP’s BSS after a first IFS interval after transmitting the control frame, wherein the first IFS interval is longer than a second IFS interval used by non-TXOP holder APs to transmit response frames after receiving the control frame.
  • the first IFS interval is a PIFS interval and the second IFS interval is a SIFS interval.
  • the sharing AP refrains from transmitting in the sharing AP’s BSS to allow the TXOP to be preempted.
  • the sharing AP starts to transmit in the sharing AP’s BSS after the TXOP has been preempted for a TXOP sharing duration.
  • control frame is a TXOP sharing control frame and the response frame is a preemption indicator frame.
  • control frame is a polling announcement frame and the response frame is a M-BA frame.
  • the method 1400 may be performed by a non- TXOP holder AP.
  • the non-TXOP holder AP may be implemented by a wireless device (e.g., wireless device 104).
  • the non-TXOP holder AP receives a control frame from a sharing AP.
  • the control frame includes a preemption enabled indicator (e.g., indicating the sharing AP’s intention to share its TXOP with a non-TXOP holder AP).
  • the preemption enabled indicator is included in a UHR-SIG field included in a preamble of the control frame.
  • the preemption enabled indicator is included in an A-control field included in the control frame.
  • the control frame is broadcasted (the control frame is a broadcasted frame).
  • the control frame includes an indication of a TXOP sharing duration.
  • the non-TXOP holder AP determines it wishes to preempt the sharing AP’s TXOP. If the non-TXOP holder AP wishes to preempt the TXOP, the method may proceed to operation 1420. Otherwise, if the non-TXOP holder AP does not wish to preempt the TXOP, the method may proceed to operation 1415 at which the non-TXOP holder AP does not transmit a response frame to the sharing AP.
  • the non-TXOP holder AP transmits a response frame to the sharing AP to indicate that the non-TXOP holder AP wishes to preempt the TXOP.
  • the response frame is transmitted to the sharing AP after a first IFS interval after receiving the control frame, wherein the first IFS interval is shorter than a second IFS interval used by the sharing AP to start transmitting in the sharing AP’s BSS after transmitting the control frame.
  • the first IFS interval is a SIFS interval and the second IFS interval is a PIFS interval.
  • the non-TXOP holder AP participates in a channel contention mechanism to try to acquire a channel.
  • the non-TXOP holder AP transmits traffic in the non-TXOP holder AP’s BSS after participating in the channel contention mechanism (if the non-TXOP holder isa able to acquire the channel), thereby preempting the sharing AP’s TXOP.
  • the non-TXOP holder AP preempts the TXOP for the TXOP sharing duration.
  • control frame is a TXOP sharing control frame and the response frame is a preemption indicator frame.
  • control frame is a polling announcement frame and the response frame is a M-BA frame.
  • the solutions and techniques provided herein may be or may be embodied in an article of manufacture in which a non-transitory machine-readable medium (such as microelectronic memory) has stored thereon instructions which program one or more data processing components (generically referred to here as a “processor” or “processing unit”) to perform the operations described herein.
  • a non-transitory machine-readable medium such as microelectronic memory
  • processor data processing components
  • processing unit processing unit
  • some of these operations might be performed by specific hardware components that contain hardwired logic (e.g., dedicated digital filter blocks and state machines). Those operations might alternatively be performed by any combination of programmed data processing components and fixed hardwired circuit components.
  • an embodiment may be an apparatus (e.g., an AP STA, a non-AP STA, or another network or computing device) that includes one or more hardware and software logic structures for performing one or more of the operations described herein.
  • an apparatus may include a memory unit, which stores instructions that may be executed by a hardware processor installed in the apparatus.
  • the apparatus may also include one or more other hardware or software elements, including a network interface, a display device, etc.
  • the present disclosure also relates to an apparatus for performing the operations herein.
  • This apparatus can be specially constructed for the intended purposes, or it can include a general-purpose computer selectively activated or reconfigured by a computer program stored in the computer.
  • a computer system or other data processing system may carry out the computer-implemented methods described herein in response to its processor executing a computer program (e.g., a sequence of instructions) contained in a memory or other non- transitory machine-readable storage medium.
  • Such a computer program can be stored in a computer readable storage medium, such as, but not limited to, any type of disk including floppy disks, optical disks, CD-ROMs, and magnetic-optical disks, read-only memories (ROMs), random access memories (RAMs), EPROMs, EEPROMs, magnetic or optical cards, or any type of media suitable for storing electronic instructions, each coupled to a computer system bus.
  • a computer readable storage medium such as, but not limited to, any type of disk including floppy disks, optical disks, CD-ROMs, and magnetic-optical disks, read-only memories (ROMs), random access memories (RAMs), EPROMs, EEPROMs, magnetic or optical cards, or any type of media suitable for storing electronic instructions, each coupled to a computer system bus.
  • the present disclosure can be provided as a computer program product, or software, that can include a machine-readable medium having stored thereon instructions, which can be used to program a computer system (or other electronic devices) to perform a process according to the present disclosure.
  • a machine-readable medium includes any mechanism for storing information in a form readable by a machine (e.g., a computer).
  • a machine-readable (e.g., computer-readable) medium includes a machine (e.g., a computer) readable storage medium such as a read only memory (“ROM”), random access memory (“RAM”), magnetic disk storage media, optical storage media, flash memory components, etc.

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Abstract

Sont divulgués dans la présente invention un procédé mis en œuvre par un point d'accès (AP) de partage pour permettre à une opportunité de transmission (TXOP) détenue par l'AP de partage d'être préemptée. Le procédé consiste à : transmettre une trame de commande, déterminer si une trame de réponse a été reçue en provenance d'au moins un AP de non-détenteur de TXOP en réponse à la trame de commande, et en réponse à la détermination du fait que la trame de réponse a été reçue en provenance d'au moins un AP de non-détenteur de TXOP, s'abstenir de transmettre dans l'ensemble de services de base (BSS) de l'AP de partage pour permettre à la TXOP d'être préemptée.
PCT/US2025/025820 2024-04-30 2025-04-22 Signalisation pour permettre une préemption d'opportunité de transmission (txop) d'ensemble de services de base se chevauchant (obss) Pending WO2025230775A1 (fr)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20210315009A1 (en) * 2020-04-01 2021-10-07 Sony Corporation Coordinated wifi stations with shared txop in time domain
US20230397249A1 (en) * 2023-08-18 2023-12-07 Juan Fang Preemption for low-latency traffic during a txop using a preemption request control frame
US20240056968A1 (en) * 2022-08-10 2024-02-15 Nxp Usa, Inc. Preemption for latency-sensitive traffic
WO2024072399A1 (fr) * 2022-09-30 2024-04-04 Intel Corporation Appareil, système, et procédé de communication pendant une opportunité de transmission (txop) sur un canal de communication sans fil

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20210315009A1 (en) * 2020-04-01 2021-10-07 Sony Corporation Coordinated wifi stations with shared txop in time domain
US20240056968A1 (en) * 2022-08-10 2024-02-15 Nxp Usa, Inc. Preemption for latency-sensitive traffic
WO2024072399A1 (fr) * 2022-09-30 2024-04-04 Intel Corporation Appareil, système, et procédé de communication pendant une opportunité de transmission (txop) sur un canal de communication sans fil
US20230397249A1 (en) * 2023-08-18 2023-12-07 Juan Fang Preemption for low-latency traffic during a txop using a preemption request control frame

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