Providing channel occupancy duration information to enable efficient non-primary channel access (NPCA) operations

Abstract

Disclosed herein is a method performed by a wireless device belonging to a first basic service set (BSS) to provide channel occupancy duration information to a second BSS to allow the second BSS to perform non-primary channel access (NPCA). The method includes determining an expected transmission opportunity (TXOP) duration of a TXOP held by the first BSS and transmitting a physical layer protocol data unit (PPDU) in a primary channel in the first BSS, wherein a preamble of the PPDU includes a signal field that includes an indication of the expected TXOP duration, wherein the expected TXOP duration is longer than a duration indicated in a duration / identifier field included in a media access control (MAC) layer portion of the PPDU.

Description

SPECIFICATIONPROVIDING CHANNEL OCCUPANCY DURATION INFORMATION TO ENABLE EFFICIENT NON-PRIMARY CHANNEL ACCESS (NPCA) OPERATIONSCROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of U.S. Provisional Application No. 63 / 681,416, filed August 9, 2024, titled “Apparatus and method for switching decisions based on the channel occupancy of adjacent BSSs for the NPCA (Non-primary channel access)”, which is hereby incorporated by reference.TECHNICAL FIELD

[0002] The present disclosure generally relates to wireless communications, and more specifically, relates to providing channel occupancy duration information to enable efficient non-primary channel access (NPCA) operations.BACKGROUND

[0003] 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.

[0004] 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. Currently under development, 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. The standard is expected to leverage advanced technologies such as multi-link operation (MLO), which allows devices toDocket No. 1002P24024W01 Client Matter No. P24-024WO1simultaneously use multiple frequency bands and channels for enhanced performance and reliability. Additionally, 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. With these advancements, 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.

[0005] In legacy IEEE 802.11 wireless networking standards, a wireless device can only access the channel when the primary 20 MHz channel is idle. If the primary 20 MHz channel is busy, a wireless device is not allowed to transmit a physical layer protocol data unit (PPDU) even if the non-primary (secondary) channel(s) is idle. Recent wireless networking standards support wide bandwidths of 320 MHz or more. With such wide bandwidths, leaving idle nonprimary channel(s) unused just because the primary 20 MHz channel is busy is seen as inefficient and a waste of channel resources. Non-primary Channel Access (NPCA) is a technology that has been proposed to address this issue. NPCA allows wireless devices to switch to a predefined non-primary channel and attempt channel access in the non-primary channel when the primary channel is busy.

[0006] NPCA operations are significantly influenced by overlapping basic service set (OBSS) operations. NPCA can be performed when an OBSS occupies the primary channel (the OBSS may be a BSS that is adjacent to the BSS to which the NPCA-capable wireless device belongs to). Thus, the duration for which NPCA can be performed depends on the channel occupancy duration of the OBSS (e.g., the transmission opportunity (TXOP) duration of a TXOP held by the OBSS). A wireless device that wishes to perform NPCA may obtain the OBSS channel occupancy duration by inspecting the signal field (included in a PHY preamble) or duration / ID field (included in a MAC layer portion) of an OBSS PPDU. However, depending on the specific network allocation vector (NAV) or TXOP duration setting approach implemented by the OBSS, these fields may not contain accurate / exact channel occupancy duration information. For example, these fields could indicate a rough estimate of the OBSS TXOP duration or indicate a duration that is longer or shorter than the actual OBSS TXOP duration. If an OBSS reserves a TXOP that is longer than its actual transmission duration, the channel can be returned to a contention-based state using a contention free end (CF-End) frame or similar mechanism.

[0007] NPCA-capable wireless devices that obtain inaccurate OBSS channel occupancy duration information may make NPCA decisions that result in lower networkDocket No. 1002P24024W01Client Matter No. P24-024WO1utilization / efficiency. For example, if a NPCA-capable wireless device obtains OBSS TXOP duration information indicating an OBSS TXOP duration that is shorter than the actual OBSS TXOP duration, the NPCA-capable wireless device may decide not to perform NPCA (e.g., because the OBSS TXOP duration is too short to justify switching channels) or perform NPCA but end the NPCA early (before the OBSS TXOP is over), which can result in the waste of channel resources.BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The disclosure will be more fully understood from the detailed description provided below and the accompanying drawings that depict various embodiments of the disclosure. However, these drawings should not be interpreted as limiting the disclosure to the specific embodiments shown; they are provided for explanation and understanding only.

[0009] Figure 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.

[0010] Figure 2 is a schematic diagram of a wireless device, in accordance with some embodiments of the present disclosure.

[0011] Figure 3 A illustrates components of a wireless device configured to transmit data, in accordance with some embodiments of the present disclosure.

[0012] Figure 3B illustrates components of a wireless device configured to receive data, in accordance with some embodiments of the present disclosure.

[0013] Figure 4 illustrates interframe space (IF S) relationships, in accordance with some embodiments of the present disclosure.

[0014] 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.

[0015] Figure 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.

[0016] Figure 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.Docket No. 1002P24024W01Client Matter No. P24-024WO1

[0017] 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.

[0018] 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.

[0019] Figure 10 is a diagram showing idle secondary channels being unused due to the primary channel being busy, according to some embodiments.

[0020] Figure 11 is a diagram showing the use of non-primary channel access (NPCA) to make use of otherwise idle secondary channels while the primary channel is busy, according to some embodiments.

[0021] Figure 12 is a diagram showing an example network topology, according to some embodiments.

[0022] Figure 13 is a diagram showing a frame exchange sequence where the overlapping basic service set (OBSS) uses the Option 1 network allocation vector (NAV) duration setting approach, according to some embodiments.

[0023] Figure 14 is a diagram showing a frame exchange sequence where the OBSS uses the Option 2 NAV duration setting approach, according to some embodiments.

[0024] Figure 15 is a diagram showing a trigger frame format, according to some embodiments.

[0025] Figure 16 is a diagram showing a user info field format for indicating expected / desired transmission opportunity (TXOP) duration information, according to some embodiments.

[0026] Figure 17 is a diagram showing a block acknowledgement (BA) frame format, according to some embodiments.

[0027] Figure 18 is a diagram showing a BA information field format, according to some embodiments.

[0028] Figure 19 is a diagram showing an association identifier (AID) traffic identifier (TID) info field format, according to some embodiments.

[0029] Figure 20 is a diagram showing a per AID TID info field format, according to some embodiments.

[0030] Figure 21 is a flow diagram of a method for providing expected TXOP duration information, according to some embodiments.Docket No. 1002P24024W01Client Matter No. P24-024WO1

[0031] Figure 22 is a flow diagram of a method for performing NPCA, according to some embodiments.

[0032] Figure 23 is a flow diagram of a method for indicating that a TXOP will last longer than a TXOP duration indicated in a PPDU, according to some embodiments.

[0033] Figure 24 is a flow diagram of a method for performing NPCA, according to some embodiments.

[0034] Figure 25 is a flow diagram of a method for providing expected TXOP duration information, according to some embodiments.

[0035] Figure 26 is a flow diagram of a method for performing NPCA, according to some embodiments.DETAILED DESCRIPTION

[0036] The present disclosure generally relates to wireless communications, and more specifically, relates to providing channel occupancy duration information to enable efficient non-primary channel access (NPCA) operations.

[0037] The present disclosure describes a solution that allows NPCA-capable wireless devices to have more accurate overlapping basic service set (OBSS) channel occupancy duration information to enable more efficient NPCA. In some cases, the network allocation vector (NAV) duration indicated in the OBSS PPDU (e.g., indicated in the duration / ID field of the media access control protocol data unit (MPDU)) or the TXOP duration indicated in the OBSS PPDU (e.g., indicated in the TXOP DURATION field included in the signal field of the PHY preamble) may not represent the actual OBSS channel occupancy duration. NPCA-capable wireless devices that overhear an OBSS PPDU may switch channels (from the primary channel to the NPCA primary channel), accepting increased power consumption in order to use channel resources more efficiently.

[0038] However, switching channels without having accurate OBSS channel occupancy duration information can result in inefficient operations. Thus, it is important to define protocols / procedures that enable NPCA to be performed with accurate OBSS channel occupancy duration information. Since the accuracy of the OBSS channel occupancy duration information obtained from an OBSS PPDU can vary depending on the type of PPDU being transmitted, the present disclosure describes solutions to ensure that NPCA-capable wireless devices have a consistent and accurate view of the OBSS channel occupancy duration. The present disclosure defines how wireless devices (e.g., that implement the ultra high reliability (UHR) or futuregeneration wireless networking standards) can provide more accurate channel occupancyDocket No. 1002P24024W01Client Matter No. P24-024WO1duration information to enable efficient NPCA operations. Using the solutions described herein may result in more efficient NPCA operations while reducing the risk of malfunctions.

[0039] For purposes of illustration, various embodiments are described herein in the context of wireless networks that are based on IEEE 802.11 standards and using terminology and concepts thereof. Those skilled in the art will appreciate that the embodiments disclosed herein can be modified / adapted for use in other types of wireless networks.

[0040] In the following detailed description, only certain embodiments of the present invention have been shown and described, simply by way of illustration. As those skilled in the art would realize, the described embodiments may be modified in different ways, all without departing from the spirit or scope of the present invention. Accordingly, the drawings and description are to be regarded as illustrative in nature and not restrictive. Like reference numerals designate like elements throughout the specification.

[0041] Figure 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). Each of the wireless 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(e.g., 802.1 la / b / g / n / p / ac / ax / bd / be). In one embodiment, 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. The TXVECTOR provides parameters for generating and / or transmitting a corresponding frame. Similarly, 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.

[0042] 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).Docket No. 1002P24024W01Client Matter No. P24-024WO1

[0043] Figure 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.

[0044] 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.

[0045] In an embodiment, 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. However, the MAC processor 212 is not limited thereto. For example, 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.

[0046] 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.

[0047] 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.

[0048] 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) andDocket No. 1002P24024W01Client Matter No. P24-024WO1provide second information received from the WLAN 100 (e.g., from another WLAN device 104 of the WLAN 100) to the baseband processor 210.

[0049] The antenna unit 250 includes one or more antennas. When Multiple-Input Multiple- Output (MIMO) or Multi-User MIMO (MU-MIMO) is used, the antenna unit 250 may include a plurality of antennas. In an embodiment, the antennas in the antenna unit 250 may operate as a beam-formed antenna array. In an embodiment, the antennas in the antenna unit 250 may be directional antennas, which may be fixed or steerable.

[0050] 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.

[0051] As described herein, many functions of the 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.

[0052] As described herein, a wide variety of electronic devices, circuits, firmware, software, and combinations thereof may be used to implement the functions of the components of the WLAN device 104. Furthermore, the WLAN device 104 may include other components, such as application processors, storage interfaces, clock generator circuits, power supply circuits, and the like, which have been omitted in the interest of brevity.

[0053] Figure 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. In an embodiment, the TxSP 324, the RF transmitter 342, and the antenna 352 correspond to the transmitting SPU 224, the RF transmitter 242, and an antenna of the antenna unit 250 of Figure 2, respectively.

[0054] 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.

[0055] The encoder 300 receives and encodes input data. In an embodiment, 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.

[0056] 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 0sDocket No. 1002P24024W01Client Matter No. P24-024WO1or Is. When the encoder 300 performs the BCC encoding, 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.

[0057] 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.

[0058] 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.

[0059] When the TxSP 324 performs a MIMO or MU-MIMO transmission, 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. The spatial mapper may use direct mapping, spatial expansion, or beamforming.

[0060] 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.

[0061] When the TxSP 324 performs a MIMO or MU-MIMO transmission, the TxSP 324 may insert cyclic shift diversities (CSDs) to prevent unintentional beamforming. 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.

[0062] When the TxSP 324 performs a MIMO or MU-MIMO transmission, some blocks before the spatial mapper may be provided for each user.

[0063] 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 symbolDocket No. 1002P24024W01Client Matter No. P24-024WO1that the GI precedes. The TxSP 324 may optionally perform windowing to smooth edges of each symbol after inserting the GI.

[0064] The RF transmitter 342 converts the symbols into an RF signal and transmits the RF signal via the antenna 352. When 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.

[0065] Figure 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. In an embodiment, 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.

[0066] The RxSP 326 includes a GI remover 318, a Fourier transformer (FT) 316, a demapper 314, a deinterleaver 312, and a decoder 310.

[0067] 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. When the received transmission is a MIMO or MU-MIMO transmission, the RF receiver 344 and the GI remover 318 may be provided for each receive chain.

[0068] 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). The FT 316 may be provided for each receive chain.

[0069] When the received transmission is the MIMO or MU-MIMO transmission, 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.

[0070] 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.

[0071] 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.

[0072] When the received transmission is the MIMO or MU-MIMO transmission, the RxSP 326 may use a plurality of demappers 314 and a plurality of deinterleavers 312Docket No. 1002P24024W01Client Matter No. P24-024WO1corresponding to the number of spatial streams of the transmission. In this case, the RxSP 326 may further include a stream deparser for combining the streams output from the deinterleavers 312.

[0073] The decoder 310 decodes the streams output from the deinterleaver 312 or the stream deparser. In an embodiment, the decoder 310 includes an FEC decoder. The FEC decoder may include a BCC decoder or an LDPC decoder.

[0074] The RxSP 326 may further include a descrambler for descrambling the decoded data. When the decoder 310 performs BCC decoding, the RxSP 326 may further include an encoder deparser for multiplexing the data decoded by a plurality of BCC decoders. When the decoder 310 performs the LDPC decoding, the RxSP 326 may not use the encoder deparser.

[0075] Before making a transmission, 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.

[0076] The PHY entity for IEEE 802.11 is based on Orthogonal Frequency Division Multiplexing (OFDM) or Orthogonal Frequency Division Multiple Access (OFDMA). In either OFDM or OFDMA Physical (PHY) layers, a STA (e.g., a wireless device 104) is capable of transmitting and receiving Physical Layer (PHY) Protocol Data Units (PPDUs) (also referred to as PLCP (Physical Layer Convergence Procedure) Protocol Data Units) that are compliant with the mandatory PHY specifications. 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. The descriptions below, for sake of completeness and brevity, refer to OFDM-based 802.11 technology. Unless otherwise indicated, a station refers to a non-AP STA.

[0077] Figure 4 illustrates Inter-Frame Space (IFS) relationships. In particular, 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 AccessDocket No. 1002P24024W01Client Matter No. P24-024WO1Category (AC) ‘i’ (AIF S [i]). Figure 4 also illustrates a slot time and a data frame is used for transmission of data forwarded to a higher layer. As shown, a WLAN device 104 transmits the data frame after performing backoff if a DIFS has elapsed during which the medium has been idle.

[0078] 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.

[0079] 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.

[0080] When the control frame is not a response frame of another frame, the WLAN device 104 transmits the control frame after performing backoff if a DIFS has elapsed during which the medium has been idle. When 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.

[0081] A WLAN device 104 that supports Quality of Service (QoS) functionality (that is, a QoS STA) may transmit the frame after performing backoff if an AIFS for an associated access category (AC) (i.e., AIFS[AC]) has elapsed. When transmitted by the QoS STA, 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.

[0082] 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.

[0083] When the WLAN device 104 detects no medium activity for the duration of a particular backoff slot, the backoff procedure shall decrement the backoff time by the slot time. When the WLAN device 104 determines that the medium is busy during a backoff slot, the backoff procedure is suspended until the medium is again determined to be idle for the duration of aDocket No. 1002P24024W01Client Matter No. P24-024WO1DIFS or EIFS period. The WLAN device 104 may perform transmission or retransmission of the frame when the backoff timer reaches zero.

[0084] 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.

[0085] 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.

[0086] 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.

[0087] After determining that the channel is not used by other devices (that is, that the channel is IDLE) during a DIFS (and performing backoff if required), the station STA1 may transmit a Request-To-Send (RTS) frame to the station STA2. Upon receiving the RTS frame, after a SIFS the station STA2 may transmit a Clear-To-Send (CTS) frame as a response to the RTS frame. If Dual-CTS is enabled and the station STA2 is an AP, 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).

[0088] When the station STA3 receives the RTS frame, it 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. When the station STA3 receives the CTS frame, it may set the NAV timer of the station STA3 for a transmission duration of subsequently transmitted frames using duration information included in the CTS frame. Upon receiving a new frame before the NAV timer expires, 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.Docket No. 1002P24024W01Client Matter No. P24-024WO1

[0089] 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.

[0090] When the NAV timer expires, 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.

[0091] When Dual -CTS is enabled, 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. 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.

[0092] 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. As shown in Figure 6, 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.

[0093] 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. In addition to peak PHY rate, different candidate features are under discussion. These 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.Docket No. 1002P24024W01Client Matter No. P24-024WO1

[0094] The focus of IEEE 802.1 Ibn (UHR) is still under discussion, with candidate features including 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), enhanced multi-link single-radio (eMLSR) extensions to AP, roaming improvements, and power-saving schemes for prolonging battery life.

[0095] Some features, such as increasing the bandwidth and the number of spatial streams, are solutions that have been proven to be effective in previous projects focused on increasing link throughput and on which feasibility demonstration is achievable.

[0096] With respect to operational bands (e.g., 2.4 / 5 / 6 GHz) for IEEE 802.1 Ibe, more than 1 GHz of additional unlicensed spectrum is likely to be available because the 6 GHz band (5.925- 7.125 GHz) is being considered for unlicensed use. This would allow APs and STAs to become tri -band devices. Larger than 160MHz data transmissions (e.g., 320 MHz or 640 MHz) could be considered to increase the maximum PHY rate. For example, 320 MHz or 160+160MHz data could be transmitted in the 6 GHz band. For example, 160+160 MHz data could be transmitted across the 5 and 6 GHz bands.

[0097] In the process of wireless communication, a transmitting station (STA) 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.

[0098] 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.

[0099] In addition to the legacy part, 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.

[0100] Figure 7 provides a more detailed description of each field in the EHT PPDU frame, including their purposes and characteristics.

[0101] Regarding the Ultra High Reliability (UHR) PPDU, its frame structure is currently undefined and will be determined through further discussions within the relevant working group or study group. This indicates that the specifics of the UHR PPDU are still under development and will be finalized based on the outcomes of future deliberations.Docket No. 1002P24024W01Client Matter No. P24-024WO1

[0102] The distributed nature of channel access networks, such as IEEE 802.11 WLANs, makes the carrier sense mechanism useful for ensuring collision-free operation. Each station (STA) uses its physical carrier sense to detect transmissions from other STAs. However, in certain situations, it may not be possible for a STA to detect every transmission. For instance, when one STA is located far away from another STA, it might perceive the medium as idle and start transmitting a frame, leading to collisions. To mitigate this hidden node problem, the network allocation vector (NAV) has been introduced.

[0103] As the IEEE 802.11 standard continues to evolve, it now includes scenarios where multiple users can simultaneously transmit or receive data within a basic service set (BSS), such as uplink (UL) and downlink (DL) multi-user (MU) transmissions in a cascaded manner. In these cases, the existing carrier sense and NAV mechanisms may not be sufficient, and modifications or newly defined mechanisms may be required to facilitate efficient and collision- free operation.

[0104] For the purpose of this disclosure, MU transmission refers to situations where multiple frames are transmitted to or from multiple STAs simultaneously using different resources. Examples of 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.

[0105] 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.

[0106] In the IEEE 802.1 lax and 802.1 Ibe specifications, 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).

[0107] 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.

[0108] Figure 9 illustrates an example scenario where an access point (AP) operating in an 80MHz bandwidth environment sends a Trigger frame to multiple associated STAs. UponDocket No. 1002P24024W01Client Matter No. P24-024WO1receiving 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.

[0109] 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. 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.

[0110] 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.

[0111] 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. Using an automatic repeat request (ARQ) approach, the receiver discards the last failed MPDU before receiving the newly retransmitted MPDU. With requirements of enhanced reliability and reduced latency, the wireless network system can evolve toward a hybrid ARQ (HARQ) approach.

[0112] There are two methods of HARQ processing. In a first type of HARQ scheme, also referred to as chase combining (CC) HARQ (CC-HARQ) scheme, signals to be retransmitted are the same as the signals that previously failed because all subpackets to be retransmitted use the same puncturing pattern. The puncturing is needed to remove some of the parity bits after encoding using an error-correction code. The reason why the same puncturing pattern is used with CC-HARQ is to generate a coded data sequence with forward error correction (FEC) and to make the receiver use a maximum-ratio combining (MRC) to combine the received, retransmitted bits with the same bits from the previous transmission. For example, information sequences are transmitted in packets with a fixed length. At a receiver, error correction and detection are carried out over the whole packet. However, the ARQ scheme may be inefficient in the presence of burst errors. To solve this more efficiently, subpackets are used. In subpacket transmissions, only those subpackets that include errors need to be retransmitted.

[0113] Since 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 subpacketsDocket No. 1002P24024W01Client Matter No. P24-024WO1increases. 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. In particular, 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. When 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.

[0114] In a second type of HARQ scheme, also referred to as an incremental redundancy (IR) HARQ (IR-HARQ) scheme, 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. The puncturing pattern used in IR-HARQ is indicated by a subpacket identity (SPID) indication. 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). In some embodiments, subpackets with corresponding SPIDs to be transmitted are in increasing order of SPID but can be exchanged / switched except for the first SPID.

[0115] 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. To support various AP coordination schemes, such as coordinated beamforming, OFDMA, TDMA, spatial reuse, and joint transmission, a predefined mechanism for APs is necessary.

[0116] In the context of coordinated TDMA (C-TDMA), 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.Docket No. 1002P24024W01Client Matter No. P24-024WO1

[0117] The operation of various AP coordination schemes has been discussed in theIEEE 802.1 Ibe and UHR standards:

[0118] Coordinated Beamforming (C-BF): Multiple APs transmit on the same frequency resource by coordinating and forming spatial nulls, allowing for simultaneous transmission from multiple APs.

[0119] Coordinated OFDMA (C-OFDMA): APs transmit on orthogonal frequency resources by coordinating and splitting the spectrum, enabling more efficient spectrum utilization.

[0120] Joint Transmission (JTX): Multiple APs transmit jointly to a given user simultaneously by sharing data between the APs.

[0121] Coordinated Spatial Reuse (C-SR): Multiple APs or STAs adjust their transmit power to reduce interference between APs.

[0122] By implementing these AP coordination schemes, WLAN systems can improve their overall throughput and efficiency by leveraging the cooperation between multiple APs.

[0123] In legacy IEEE 802.11 wireless networking standards, transmission is only allowed when the primary 20 MHz channel is idle. This is to ensure that multiple contending wireless devices attempt channel access in the same channel, providing all wireless devices equal opportunities to access the channel. However, as wireless device performance and capabilities have advanced, the available operating bandwidth has increased, with recent wireless devices supporting up to 320 MHz operating bandwidths. With the increase in operating bandwidths, only allowing transmission when the primary 20 MHz channel is idle can be seen as inefficient and as a waste of channel resources. Figure 10 is a diagram illustrating this inefficiency.

[0124] Figure 10 is a diagram showing idle secondary channels being unused due to the primary channel being busy, according to some embodiments.

[0125] The diagram shows an example where the operating bandwidth is 160 MHz. The 160 MHz operating bandwidth may include a primary 20 MHz channel (channel #0), a secondary 20 MHz channel (channel #1), a secondary 40 MHz channel (composed of channels #2 and #3), and a secondary 80 MHz channel (composed of channels #4, #5, #6, and #7).

[0126] It is assumed in this example that there is a first BSS that includes NPCA-capable STAs (the first BSS may be referred to as “MyBSS”) and a second BSS that overlaps with the first BSS (the second BSS may be referred to as an “OBSS” with respect to MyBSS).

[0127] In the example shown in the diagram, after performing a backoff procedure at time tO, the OBSS occupies a 40 MHz band that includes the primary 20 MHz channel and the secondary 20 MHz channel (OBSS PPDU exchange). In such a scenario, NPCA-capable STAs that belong to MyBSS (referred to herein as MyBSS STAs) may attempt to access the channelDocket No. 1002P24024W01Client Matter No. P24-024WO1at tO (or shortly thereafter) but may be unable to access the channel due to the OBSS PPDU exchange occupying the primary 20 MHz channel. The MyBSS STAs may be unable to access the channel until time tl even though the secondary channels (e.g., the secondary 40 MHz channel and the secondary 80 MHz channel) are idle during the OBSS PPDU exchange. Thus, the MyBSS STAs have to wait until after time tl to perform a PPDU exchange (the 80 MHz PPDU exchange).

[0128] Leaving the idle non-primary (secondary) channels unused just because the primary 20 MHz channel is busy is a waste of channel resources. The use of NPCA may help better utilize the idle channel resources and improve overall network performance and latency. As mentioned earlier, the use of NPCA may enhance network efficiency by allowing NPCA- capable wireless devices to switch to a predefined non-primary (secondary) channel when the primary 20 MHz channel is busy.

[0129] Figure 11 is a diagram showing the use of NPCA to make use of otherwise idle secondary channels while the primary channel is busy, according to some embodiments.

[0130] The diagram illustrates how the use of NPCA technology can improve network efficiency. As shown in the diagram, an OBSS PPDU exchange may occupy the primary 20 MHz channel and the secondary 20 MHz channel for a period of time. NPCA-capable MyBSS STAs that detect the OBSS PPDU exchange may switch to a predefined anchor channel (the NPCA primary channel, which in this example is channel #2) among the secondary channels. The NPCA-capable MyBSS STAs may perform a backoff procedure in the predefined anchor channel just as they would in the primary channel and then perform a PPDU exchange in the idle secondary channel(s) including the anchor channel. For example, the NPCA-capable MyBSS STAs may perform a 40 MHz PPDU exchange in the secondary 40 MHz channel and perform a 80 MHz PPDU exchange in the secondary 40 MHz channel and the lower 40 MHz of the secondary 80 MHz channel during the time that the OBSS PPDU exchange occupies the primary 20 MHz channel.

[0131] NPCA can be performed while the OBSS occupies the primary channel. Thus, knowing the expected OBSS channel occupancy duration is an important aspect of performing NPCA.

[0132] The OBSS channel occupancy duration information (information regarding how long the OBSS will occupy the primary channel) can be obtained from the PHY preamble or MAC frame fields of an OBSS PPDU (i.e., a PPDU transmitted by an OBSS AP / STA). Notably, the duration / ID field (included in the MAC header) or the TXOP duration field (included in theDocket No. 1002P24024W01Client Matter No. P24-024WO1signal field of the PHY preamble) included in an OBSS PPDU can be used to infer the OBSS channel occupancy duration.

[0133] NPCA-capable STAs may use the channel occupancy duration information inferred from the OBSS PPDU to determine whether to switch to a non-primary (secondary) channel and to determine how long it can transmit traffic in the non-primary channel. Thus, the channel occupancy duration information inferred from the OBSS PPDU can significantly impact the efficiency and performance of NPCA.

[0134] The OBSS channel occupancy duration can be inferred from the NAV duration information (e.g., included in a duration / ID field) or TXOP duration information (e.g., included in the signal field of the PHY preamble) obtained from an OBSS PPDU. However, the way that the OBSS sets the NAV / TXOP duration in the PPDUs that it transmits is beyond the control of the NPCA-capable MyBSS APs / STAs. Consequently, NPCA procedures should be carried out with a precise understanding of the OBSS TXOP / NAV duration settings.

[0135] From an implementation perspective, there are several ways that TXOP holders can set the NAV duration to protect its TXOP. Two different NAV duration setting approaches (referred to as “Option 1” and “Option 2”) are described herein below.Option 1: TXOP holder sets the NAV duration to the entire TXOP duration required by the TXOP holder in a single step

[0136] One way that a TXOP holder can set the NAV duration is to set it to the entire duration of the TXOP. In this case, unforeseen situations can arise. For example, the buffer unit (BU) data transmission may be completed before the NAV expires. As an example, due to the use of rate adaptation, the transmission may finish earlier than expected. Thus, the TXOP holder may have transmitted all of its traffic but there may be time remaining in the TXOP based on the pre-set NAV duration. In such case, the TXOP holder may transmit a CF-End frame to relinquish the TXOP and allow contention-based access to resume, thereby improving channel utilization. As another example, if the BU data arrival time at the MAC layer is uncertain, the TXOP holder may set the NAV duration using an estimate of the TXOP duration. For example, the TXOP holder may set the NAV duration to a sufficiently long duration (overestimate) to be safe. Since the channel is reserved for a sufficiently long time, the TXOP holder may finish transmitting its buffered unit data before the NAV expires. In such case, the TXOP holder may transmit a CF-End frame to relinquish the TXOP. However, the act of transmitting a CF-End frame in the scenarios described above can reduce efficiency (e.g., since it adds an additional frame transmission).Docket No. 1002P24024W01Client Matter No. P24-024WO1

[0137] In some cases, the TXOP holder may not be able to transmit all of its BU data within the initially set NAV duration. For example, in the case of pre-HE STA and non-AP STA based on HE / EHT standards, the channel can be reserved using request-to-send (RTS) and clear-to- send (CTS) frames. Assume a scenario where the TXOP holder and TXOP responder have the dynamic bandwidth signaling feature enabled. If the TXOP holder transmits a RTS frame in a 80 MHz bandwidth and the TXOP responder responds by transmitting a CTS frame in a small er / narrower bandwidth (e.g., 20 MHz or 40 MHz bandwidth), the TXOP holder may need more time to transmit the data than the NAV duration set in the RTS frame (since the TXOP holder has to transmit data in a smaller / narrower bandwidth). If there is still time remaining in the TXOP, the TXOP holder may decide to occupy the channel for a longer time. In such case, a NPCA-capable STA that switches channels after overhearing the RTS / CTS frame exchange may decide to return to the primary channel before the TXOP holder is finished transmitting (because the NPCA-capable STA does not realize that the TXOP holder is going to occupy the channel for a longer time). However, it may have been more efficient for the NPCA-capable STA to continue performing NPCA in the non-primary channel until the TXOP holder is finished transmitting.Option 2: The TXOP holder sets the NAV duration to the minimum duration required for the upcoming frame exchange and then continues occupying the channel by setting a minimum NA V duration in each subsequent PPDU

[0138] Another way that a TXOP holder can set the NAV duration is to set it to the minimum duration required for the upcoming frame exchange and then continue occupying the channel by setting a minimum NAV duration in each subsequent PPDU. The Option 1 NAV duration setting approach can reduce channel utilization efficiency so some legacy wireless devices may choose to use the Option 2 approach.

[0139] When NPCA-capable STAs overhear the frame exchange sequence of OBSS STAs that use the Option 2 NAV duration setting approach, they might conclude that there is little to no benefit in performing NPCA. That is, if the expected OBSS channel occupancy duration in the primary channel is short, the NPCA-capable STAs may decide against channel switching for NPCA because performing NPCA for just a short duration may not provide enough benefit to outweigh the additional power consumption required to perform NPCA (the margin of gain is insufficient).Docket No. 1002P24024W01Client Matter No. P24-024WO1

[0140] NPCA-capable STAs may not be able to determine which NAV duration setting approach the OBSS is using. Regardless of which NAV duration setting approach the OBSS uses, NPCA operations should be able to run efficiently.

[0141] The two NAV duration setting approaches are further described in the context of an example network topology.

[0142] Figure 12 is a diagram showing an example network topology, according to some embodiments.

[0143] As shown in the diagram, the network includes API and its associated STAs (STA1-1 and STA1-2), which in this example are NPCA-capable STAs. API and its associated STAs may belong to a first BSS (“MyBSS”). The network further includes AP2 and its associated STA (STA2-1). AP2 and its associated STA may belong to a second BSS (“OBSS”) that is adjacent to MyBSS. Thus, AP2 may be an OBSS AP with respect to MyBSS and STA2-1 may be an OBSS STA with respect to MyBSS.

[0144] When the NPCA-capable MyBSS AP / STAs overhear a PPDU transmitted by the OBSS (e.g., transmitted by AP2), they may switch to a non-primary channel (the NPCA primary channel) and transmit in the non-primary channel for a NAV duration obtained from the OBSS PPDU.

[0145] Figure 13 is a diagram showing a frame exchange sequence where the OBSS uses the Option 1 NAV duration setting approach, according to some embodiments.

[0146] The diagram shows an example where the OBSS uses the Option 1 NAV duration setting approach and extends the TXOP when all of the BU data cannot be transmitted within the initially set NAV duration.

[0147] As shown in the diagram, AP2 may transmit a (MU-)RTS frame 1305 (multi-user RTS frame or regular RTS frame) in an 80 MHz bandwidth using a non-HT duplicated PPDU. It is assumed that AP2 and STA2-1 support dynamic bandwidth operation so STA2-1 may respond by transmitting a CTS frame 1310 in the available 40 MHz bandwidth. If STA1-1 (which is a NPCA-capable STA) interprets the NAV duration at time tO after only overhearing the (MU-)RTS frame 1305 and begins performing NPCA, it may switch back to the primary channel by time t2.

[0148] After receiving CTS frame 1310 from STA2-1, AP2 may realize that it needs to transmit data using a 40 MHz bandwidth and thus it may take a longer time to transmit its BU data (since it takes longer to transmit the same amount of data using a small er / narrower bandwidth). Thus, when transmitting 40 MHz PPDU1 1315, AP2 may extend the NAV such that the NAV expires at time t4 (by setting the NAV duration in PPDU1 1315 such that theDocket No. 1002P24024W01Client Matter No. P24-024WO1NAV expires at time t4 instead of expiring at time t2). The transmission of PPDU1 1315 may end at time tl . STA2- 1 may respond to PPDU 1 1315 by transmitting block acknowledgement (BA) frame 1320 (in a non-HT duplicated PPDU). AP2 may then transmit 40 MHzPPDU2 1325. The transmission of PPDU2 1325 may end at time t2. STA2-1 may respond to PPDU2 1325 by transmitting BA frame 1330. AP2 may then transmit 40 MHz PPDU3 1335. The transmission of PPDU3 1335 may end at time t3. STA2-1 may respond to PPDU3 1335 by transmitting BA frame 1340.

[0149] STA1-1, which started performing NPCA after only overhearing (MU-)RTS frame 1305, may switch back to the primary channel at time t2 even though the OBSS TXOP has been extended until time t4. That is, STA1-1 may switch back to the primary channel at time t2 even though it could have continued performing NPCA in the non-primary channel for a longer time (until time t4). This may be an inefficient use of channel resources.

[0150] In an embodiment, STA1-1 determines whether to perform NPCA and how long to perform NPCA (the NPCA duration) based on TXOP duration information obtained from PPDU1 1315 (instead of the TXOP duration information obtained from (MU-)RTS frame 1305). For example, if the TXOP duration information obtained from PPDU1 1315 indicates a duration that is longer than the duration indicated by the TXOP duration information obtained from (MU- )RTS frame 1305 (or otherwise indicates that the TXOP will be extended), STA1-1 may decide to use the TXOP information obtained from PPDU1 1315 to perform NPCA. More generally, a wireless device may use TXOP duration information obtained from the third PPDU in a PPDU sequence / exchange to perform NPCA.

[0151] Figure 14 is a diagram showing a frame exchange sequence where the OBSS uses the Option 2 NAV duration setting approach, according to some embodiments.

[0152] The diagram shows an example where the OBSS uses the Option 2 NAV duration setting approach by incrementally extending the TXOP.

[0153] As shown in the diagram, AP2 may transmit a (MU-)RTS frame 1405 in an 80 MHz bandwidth (using a non-HT duplicated PPDU), STA2-1 may transmit CTS frame 1410 in an 80 MHz bandwidth (using a non-HT duplicated PPDU), AP2 may transmit 80 MHz PPDU1 1415, STA2-1 may transmit BA frame 1420, AP2 may transmit 80 MHz PPDU2 1425, STA2-1 may transmit BA frame 1430, AP2 may transmit 80 MHz PPDU3 1435, and STA2-1 may transmit BA frame 1440.

[0154] AP2 may set the NAV duration in the (MU-)RTS frame 1405 for the minimum duration needed to transmit a single PPDU (duration dO). In the example shown in the diagram, the NAV duration indicated in (MU-)RTS frame 1450 is set such that the NAV expires atDocket No. 1002P24024W01Client Matter No. P24-024WO1time tl (when the transmission of PPDU1 1415 ends) but the NAV duration could also be set such that the NAV expires when the transmission of BA frame 1420 ends. Similarly, the NAV duration or the TXOP duration in 80 MHz PPDU1 1415 may be set to a SIFS+ACK TIME duration (duration dl). Assume that STA1-1 overhears PPDU1 1415 at time tl and considers performing NPCA. In this scenario, STA1-1 might decide not to perform NPCA because the NAV duration indicated in PPDU1 (duration dl) is not long enough to justify switching channels. However, unbeknownst to STA1-1, the OBSS will actually continue transmitting traffic until time t4, with the TXOP lasting for a total duration of d4. If STA1-1 does not perform NPCA during this time, it may result in the waste of channel resources.

[0155] Solutions are described herein to provide NPCA-capable STAs with OBSS channel occupancy duration information that can help resolve the ambiguities that can arise with the different NAV duration setting approaches mentioned above.

[0156] It is recognized by the present disclosure that the NAV duration set in a PPDU is not necessarily equivalent to the actual TXOP duration. It is important to ensure that NPCA-capable STAs have accurate or somewhat accurate OBSS channel occupancy duration information to perform efficient NPCA operations. Also, it is important to ensure that there is sufficient performance / efficiency gain from performing NPCA to offset any of the drawbacks associated with performing NPCA such as increased power consumption. In an embodiment, in the UHR or future-generation wireless networks, STAs may provide additional information in the PPDUs they transmit to allow NPCA-capable STAs to have a more accurate view of the channel occupancy duration. UHR or future-generation NPCA-capable STAs that overhear such PPDUs may make NPCA-related decisions (e.g., whether to perform NPCA and how long to perform NPCA) based on the additional information provided in the PPDUs. This approach may be particularly useful in cases where the OBSS STAs use the Option 2 NAV duration setting approach. The Option 2 NAV duration setting approach helps prevent surrounding STAs from setting overly long NAVs and thus allows for more efficient use of the channel. However, for NPCA operations, it does not provide accurate / actual channel occupancy duration. The additional information (e.g., expected / desired TXOP duration) provided by embodiments described herein may help NPCA-capable have more accurate channel occupancy duration in such scenarios.

[0157] Five solutions (Solutions 1-5) are described herein below. It should be appreciated that some of the solutions may be used together. That is, some of the solutions can be combined.Docket No. 1002P24024W01Client Matter No. P24-024WO1Solution 1: TXOP duration threshold based channel switching

[0158] In this solution, NPCA may be performed based on the TXOP duration information obtained from the overheard OBSS PPDU. However, if the OBSS TXOP duration indicated by the TXOP duration information is shorter than a predefined threshold duration that is known to the STAs that belong to MyBSS, NPCA is not performed.

[0159] The predefined threshold duration can be periodically shared / updated by the AP through beacon or probe response frames or provided during the association phase (e.g., provided with other information needed for performing NPCA such as an OBSS list (e.g., indicating the OBSSs that ).

[0160] If a situation where it is frequent for the TXOP duration obtained from an OBSS PPDU to be shorter than the predefined threshold duration (e.g., which might be the case when the OBSS uses the Option 2 NAV duration setting approach), the opportunities to perform NPCA may be significantly reduced.Solution 2: Channel switching for a fixed NPCA duration

[0161] This solution may help overcome the situation where sufficient NPCA opportunities cannot be obtained due to the OBSS channel occupancy duration being too short.

[0162] A first case that is considered is when the overheard OBSS PPDU is a pre-UHR PPDU. When performing NPCA based solely on information obtained from interpreting the PHY preamble, STAs belonging to MyBSS may switch to the non-primary channel to perform NPCA for a fixed NPCA duration that has been pre-designated in MyBSS. The fixed NPCA duration may be determined by referencing a TXOP limit table (e.g., from the EDC A parameter set defined in the IEEE 802.11 wireless networking standard) to ensure that the fixed NPCA duration does not exceed the maximum TXOP duration defined by the wireless networking standard. When performing NPCA based on information obtained from interpreting the MAC frame, if the frame received from the OBSS is a QoS frame or a variant of a BA frame, access category or traffic identifier information can be obtained from the AC / TID (the access category and traffic identifier) field of the frame. The MyBSS NPCA-capable STA may determine the maximum TXOP limit associated with the AC / TID (e.g., as specified by the TXOP limit table) and use this to estimate the maximum duration that the OBSS will occupy the primary channel. Although the exact OBSS channel occupancy duration may not be known, the goal of NPCA- capable STAs is to maximize the use of available transmission opportunities. Thus, NPCA- capable STAs may perform NPCA for the duration they predict that the OBSS will occupy theDocket No. 1002P24024W01Client Matter No. P24-024WO1primary channel. NPCA-capable STAs may switch to the non-primary channel to perform NPCA for a fixed NPCA duration defined in advance for each AC / TID.

[0163] A second case that is considered is when the overheard PPDU is a UHR PPDU. If the signal field provides information regarding the traffic characteristics or queue characteristics such as AC (access category), TID (traffic identifier), and / or TSID (traffic stream identifier), NPCA-capable STAs may switch to a non-primary channel to perform NPCA based on this information for a fixed NPCA duration. If the access category information is available, NPCA can be performed for a NPCA duration that does not exceed the TXOP duration limit associated with the access category (e.g., as specified by the TXOP limit), and this NPCA duration may have been pre-designated among the AP STA and non-AP STAs that belong to MyBSS.

[0164] In the scenarios described in the above two cases (pre-UHR and UHR cases), if NPCA-capable STAs receive a PPDU in the non-primary channel with a NAV duration setting that exceeds a certain threshold, they may return to the original primary channel.Solution 3: UHR signal field or U-SIG field indicates the expected / de sired TXOP duration

[0165] If it is assumed that the OBSS only includes STAs that implement the UHR wireless networking standard or subsequent wireless networking standards, then the OBSS STAs may be able to provide valuable channel occupancy duration information in the PHY preamble of the PPDUs that they transmit that can help adjacent BSSs to perform NPCA more efficiently.

[0166] In an embodiment, an OBSS STA provides its desired / expected TXOP duration in the PPDUs that it transmits. In that case, adjacent BSS APs / STAs (e.g., MyBSS AP / STAs) that overhear an OBSS PPDU may perform NPCA based on more accurate OBSS channel occupancy duration information. To facilitate this, the TXOP holder may include the minimum TXOP duration it intends to use in the signal field of the PPDU that it transmits. Currently, the TXOP duration field is included in the signal field (of the PHY preamble) starting from the IEEE 802.11 HE wireless networking standard. However, this TXOP duration field typically indicates a duration that is shorter than the duration indicated in the MAC layer's duration / ID field, so it cannot be interpreted as being an accurate reflection of the total TXOP duration.

[0167] Thus, in an embodiment (e.g., in the UHR wireless networking standard and / or subsequent wireless networking standards), the TXOP duration field included in the U-SIG field can be redefined or reinterpreted as indicating the expected / desired TXOP duration.

[0168] Up until the EHT wireless networking standard, the TXOP duration(TXOP DURATION) value included in the U-SIG field could not be set to a value that is larger than the value included in the MAC layer’s duration / ID field. However, in an embodiment, thisDocket No. 1002P24024W01Client Matter No. P24-024WO1restriction can be relaxed, allowing the expected / desired TXOP duration to be indicated in the TXOP duration field included in the U-SIG field.

[0169] In general, if an EHT STA can interpret the MAC layer’s duration / ID field, it will set its NAV based on the NAV duration indicated therein to minimize the risk of malfunction.However, if an EHT STA located at the edge of the UHR STA's coverage cannot interpret the MAC field, it may set its NAV using the TXOP duration value obtained from the PHY preamble. In such cases, the EHT STA’s NAV might be set based on the expected / desired TXOP duration, resulting in the EHT STA’s NAV to be longer. While this might impose excessive constraints in terms of protection, it offers the benefit of providing robust protection.

[0170] Alternatively, in an embodiment, a new expected / desired TXOP duration field for indicating the expected / desired TXOP duration can be defined and included in a PPDU. This field may use the same time resolution as the existing TXOP duration field, allowing it to indicate a wide range of durations with a limited number of bits. This new field may be included in the U-SIG field, UHR-SIG field, or signal fields of a PPDU (e.g., in addition to the existing TXOP duration field).

[0171] When using the Option 2 NAV duration setting approach, it may be beneficial to indicate the expected / desired TXOP duration in a field that is separate from the duration / ID field and the TXOP duration field (e.g., TXOP DURATION field included in the U-SIG field). When using the Option 1 NAV duration setting approach, information regarding the expected / desired TXOP duration may be included in the duration / ID field, the TXOP duration field, or in a separate / new field (which may be included in the MAC layer portion or the PHY preamble). The information regarding the expected / desired TXOP duration may be included in the third PPDU in a PPDU exchange sequence.

[0172] In an embodiment, the UHR signal field or U-SIG field includes a “more PPDU” indication for indicating whether there will be more PPDUs forthcoming. Although the TXOP holder may not know the exact TXOP duration it will use, it may provide an indication that it will likely continue to use the TXOP.

[0173] When a NPCA-capable STA detects the more PPDU indication in an overheard OBSS PPDU, it may perform NPCA even if the TXOP duration indicated in the OBSS PPDU is shorter than a predefined threshold duration. The duration for performing NPCA can be set to a predefined duration from the wireless networking standard’s TXOP limit table or a predefined duration that was agreed upon between the NPCA-capable STAs, whichever is shorter. It is assumed that the predefined threshold duration and the NPCA duration have been pre-Docket No. 1002P24024W01Client Matter No. P24-024WO1designated among the NPCA-capable non-AP STA and the associated NPCA-capable AP or is otherwise known to them.Solution 4: The initial control frame (ICF) or control response frame (CRF) / initial control response (ICR) frame indicates the expected / desired TXOP duration

[0174] In an embodiment, the TXOP holder indicates the expected / desired TXOP duration that the TXOP holder intends to use in a MAC field of an ICF. Additionally or alternatively, the TXOP responder may indicate the expected / desired TXOP duration in a MAC field of the CFR / ICR (or other response frame) based on the TXOP duration information it received from the TXOP holder.

[0175] ICF and CRF / ICR are MAC layer control frames, which can be variants of a trigger frame, a BA request frame, and / or BA frame.

[0176] For example, if the expected / desired TXOP duration is indicated in the ICF, STAs (e.g., STAs that implement UHR or a future-generation wireless networking standards) may use the duration / ID field to set their NAVs and use the TXOP duration field to obtain duration information for performing NPCA. Legacy STAs would not interpret the expected / desired TXOP duration field and would only use the duration / ID field to set their NAVs.

[0177] In an embodiment, an AP / STA includes unavailability duration information in the ICF / ICR instead of the expected / desired TXOP duration. For example, if the AP / STA is about to enter a power save mode or other type of operation mode that prevents transmission or reception, it may transmit an ICF that includes unavailability duration information to notify others of its upcoming unavailability. When a NPCA-capable STA receives such an ICF from an OBSS AP, it may not perform channel switching for NPCA even if it detects transmissions by STAs belonging to that OBSS during the unavailability duration. This is because the AP that transmits the ICF will not properly respond to PPDUs transmitted by the OBSS non-AP STAs that the NPCA-capable STA overheard. That is, since the OBSS will not successfully obtain the TXOP, there is no need for the NPCA-capable STA to switch channels.

[0178] In an embodiment, the ICF is a variant of trigger frame such as a buffer status report poll (BSRP) trigger frame. It is also possible to define a new trigger frame variant using a reserved value in the trigger type field.

[0179] Figure 15 is a diagram showing a trigger frame format, according to some embodiments.

[0180] As shown in the diagram, the trigger frame includes a frame control field 1505 (2 octets), a duration field 1510 (2 octets), a RA (receiver address) field 1515 (6 octets), a TADocket No. 1002P24024W01Client Matter No. P24-024WO1(transmitter address) field 1520 (6 octets), a common info field 1525 (8 or more octets), a user info list field 1530 (variable length), a padding field 1535 (variable length), and a frame check sequence (FCS) field 1540 (4 octets). For sake of brevity / conciseness, the description focuses on fields that are particularly relevant for providing channel occupancy duration information. The fields that are not specifically described in detail herein can be interpreted in accordance with IEEE 802.11 wireless networking standards.

[0181] The user info list field 1530 may include multiple user info fields. A user info field may include an AID 12 field for specifying the recipient of the user info field. Certain values for the AID 12 field may be reserved to convey different (non-user specific) meanings in the user info field. In an embodiment, the AID 12 field includes a particular value to indicate that the user info field includes expected / desired TXOP duration information or unavailability duration information.

[0182] Figure 16 is a diagram showing a user info field format for indicating expected / desired TXOP duration information, according to some embodiments.

[0183] As shown in the diagram, the user info field includes an AID 12 field 1605 (12 bits), a time info type field 1610 (2 bits), a time information field 1615 (14 bits), and a reserved field 1620 (12 bits).

[0184] In an embodiment, a new value for the AID 12 field can be defined to indicate that the user info field indicates the expected / desired TXOP duration. For example, the AID12 field 1605 may be set to a value of 2009 to indicate that the user info field indicates the expected / desired TXOP duration (it should be appreciated, however, that values other than 2009 can be used for this purpose).

[0185] The time info type field 1610 may indicate whether the user info field indicates TXOP duration or unavailability duration. For example, when the time info type field 1610 has a length of 2 bits, it may include one of the following values with the corresponding meaning: 1) binary 00: Reserved; 2) binary 01 : TXOP duration; 3) binary 10: Unavailability duration; or 4) binary 11 : Reserved.

[0186] The time information field 1615 may indicate the TXOP duration or the unavailability duration depending on the value included in the time info type field 1610. In an embodiment, the time information field 1615 has a length of 14 bits and can express a duration of up to 16 milliseconds.

[0187] The reserved field 1620 may be reserved for future use.

[0188] In an embodiment, the ICR / CRF may be a variant of a BA frame.

[0189] Figure 17 is a diagram showing a BA frame format, according to some embodiments.Docket No. 1002P24024W01Client Matter No. P24-024WO1

[0190] As shown in the diagram, the BA frame may include a frame control field 1705 (2 octets), a duration field 1710 (2 octets), a RA field 1715 (6 octets), a TA field 1720 (6 octets), a BA control field 1725 (2 octets), a BA information field 1730 (variable length), and a FCS field 1735 (4 octets).

[0191] In an embodiment, the BA information field 1730 includes TXOP duration-related information. For example, if the BA frame is a multi-STA BA frame, the BA information field 1730 may include a per AID TID info field (e.g., field 1805 shown in Figure 18) that indicates TXOP duration-related information.

[0192] Figure 18 is a diagram showing a BA information field format, according to some embodiments. As shown in the diagram, the BA information field 1730 (e.g., included in a multi-STA BA frame) may include a per AID TID info field 1805 for each <AID, TID> tuple.

[0193] Each per AID TID info field 1805 may include an AID TID info field and a timing information field (e.g., as shown in Figure 20).

[0194] Figure 19 is a diagram showing an AID TID info field format, according to some embodiments. As shown in the diagram, the AID TID info field may include an AID11 field 1905 (11 bits), an ACK type field 1910 (1 bit), and a TID field 1915 (4 bits).

[0195] Figure 20 is a diagram showing a per AID TID info field format for indicating duration information, according to some embodiments.

[0196] As shown in the diagram, the per AID TID info field may include an AID TID info field 2005 (2 octets) and a timing info field 2010 (2 octets).

[0197] The AID TID info field 2005 may have the format shown in Figure 19 or similar format. In an embodiment, to maintain consistency with the ICF example describe above, the AID11 field 1905 included in the AID TID info field 2005 may be set to a value of 2009 to indicate that the per AID TID info field 1805 indicates duration information.

[0198] The timing info field 2010 may include a time info type field and a time information field that are similar to the time info type field 1610 and time information field 1615 shown in Figure 16, respectively, and described above. For example, in an embodiment, the time info type field has a length of 2 bits and may include one of the following values with the corresponding meaning: 1) binary 00: Reserved; 2) binary 01 : TXOP duration; 3) binary 10: Unavailability duration; or 4) binary 11 : Reserved. The time information field may indicate the expected / desired TXOP duration or the unavailability duration depending on the value included in the time info type field. In an embodiment, the time information field has a length of 14 bits and can express a duration of up to 16 milliseconds.Docket No. 1002P24024W01Client Matter No. P24-024WO1

[0199] In an embodiment, to support multiple users, the BA information field included in the MU-BAR (multi-user block acknowledgement request) trigger frame can be configured using the per AID TID info field mentioned above.Solution 5: Service period based NPCA

[0200] During a coordinated r-TWT SP (restricted target wake time service period) of an OBSS, NPCA-capable MyBSS STAs should adhere to the service period intervals of the OBSS (i.e., avoid transmitting during the r-TWT SP). In an embodiment, NPCA-capable STAs can attempt to perform NPCA during the r-TWT service periods of the OBSS.

[0201] However, it is possible that the primary channel is not busy during the r-TWT service period or the r-TWT service period could be canceled. In an embodiment, to account for this, NPCA is not performed if no OBSS PPDU / frame exchange is detected in the primary channel within a designated time. If, however, an OBSS PPDU / frame exchange is detected, an NPCA- capable STA may switch channels to perform NPCA during the predefined r-TWT service period, regardless of the TXOP duration indicated in the OBSS PPDU. The NPCA-capable STA may perform backoff in the non-primary channel to acquire the non-primary channel. If the NPCA-capable STA receives a PPDU that sets a NAV that extends beyond the predefined r- TWT service period in the non-primary channel, the NPCA-capable STA may return to the primary channel before the r-TWT service period ends.

[0202] The present disclosure describes solutions to address the ambiguities that can arise when an NPCA-capable wireless device wishes to perform NPCA. In an embodiment, OBSS wireless devices provide the expected / desired TXOP duration information in the PPDUs that they transmit to allow NPCA-capable wireless devices to have more accurate OBSS channel occupancy duration information. This allows the NPCA-capable wireless devices to perform NPCA more efficiently, thereby improving channel utilization in both the primary channel and non-primary channel.

[0203] Turning now to Figure 21, a method 2100 will be described for providing expected TXOP duration information, in accordance with an example embodiment. The method 2100 may be performed by a wireless device (e.g., wireless device 104) that belongs to a first BSS to provide expected TXOP duration information to other BSSs.

[0204] Additionally, although shown in a particular order, in some embodiments the operations of the method 2100 (and the other methods shown in the other figures) may be performed in a different order. For example, although the operations of the method 2100 areDocket No. 1002P24024W01Client Matter No. P24-024WO1shown in a sequential order, some of the operations may be performed in partially or entirely overlapping time periods.

[0205] At operation 2105, the wireless device determines an expected TXOP duration of a TXOP held by the first BSS.

[0206] At operation 2110, the wireless device transmits a PPDU in a primary channel in the first BSS, wherein a preamble of the PPDU includes a signal field that includes an indication of the expected TXOP duration, wherein the expected TXOP duration is longer than a duration indicated in a duration / identifier field included in a MAC layer portion (e.g., MPDU) of the PPDU. In an embodiment, the signal field is a UHR signal field or a U-SIG field. In an embodiment, the indication of the expected TXOP duration is included in a TXOP duration field included in the signal field. In an embodiment, the signal field includes a TXOP duration field and an expected TXOP duration field, wherein the indication of the expected TXOP duration is included in the expected TXOP duration field. In an embodiment, the duration indicated in the duration / identifier field indicates how long wireless devices should set their NAVs for.

[0207] Turning now to Figure 22, a method 2200 will be described for performing NPCA, in accordance with an example embodiment. The method 2200 may be performed by a wireless device (e.g., wireless device 104) that belongs to a first BSS.

[0208] At operation 2205, the wireless device overhears a PPDU transmitted in a primary channel in a second BSS, wherein a preamble of the PPDU includes a signal field that includes an indication of an expected TXOP duration of a TXOP held by the second BSS, wherein the expected TXOP duration is longer than a duration indicated in a duration / identifier field included in a MAC layer portion of the PPDU. In an embodiment, the signal field is a UHR signal field or a U-SIG field. In an embodiment, the indication of the expected TXOP duration is included in a TXOP duration field included in the signal field. In an embodiment, the signal field includes a TXOP duration field and an expected TXOP duration field, wherein the indication of the expected TXOP duration is included in the expected TXOP duration field. In an embodiment, the duration indicated in the duration / identifier field indicates how long wireless devices should set their NAVs for.

[0209] At operation 2210, responsive to overhearing the PPDU, the wireless device performs NPCA in a NPCA primary channel in the first BSS for the expected TXOP duration.

[0210] Turning now to Figure 23, a method 2300 will be described for indicating that a TXOP will last longer than a TXOP duration indicated in a PPDU, in accordance with an example embodiment. The method 2300 may be performed by a wireless device (e.g., wirelessDocket No. 1002P24024W01Client Matter No. P24-024WO1device 104) that belongs to a first BSS to indicate to other BSSs that a TXOP held by the first BSS will last longer than a TXOP duration indicated in a PPDU.

[0211] At operation 2305, the wireless device transmits a PPDU in a primary channel in the first BSS, wherein a preamble of the PPDU includes a signal field that includes an indication that a TXOP held by the first BSS will last longer than a TXOP duration indicated in the PPDU. In an embodiment, the signal field is a UHR signal field or a U-SIG field.

[0212] Turning now to Figure 24, a method 2400 will be described for performing NPCA, in accordance with an example embodiment. The method 2400 may be performed by a wireless device (e.g., wireless device 104) that belongs to a first BSS.

[0213] At operation 2405, the wireless device overhears a PPDU transmitted in a primary channel in a second BSS, wherein a preamble of the PPDU includes a signal field that includes an indication that a TXOP held by the second BSS will last longer than a TXOP duration indicated in the PPDU.

[0214] At operation 2410, the wireless device determines that the TXOP held by the second BSS will last longer than the TXOP duration indicated in the PPDU based on the indication.

[0215] At operation 2415, responsive to determining that the TXOP held by the second BSS will last longer than the TXOP duration indicated in the PPDU, the wireless device performs NPCA in a NPCA primary channel in the first BSS despite the TXOP duration indicated in the PPDU being shorter than a minimum NPCA duration threshold (the minimum duration need to perform NPCA). In an embodiment, the NPCA is performed for a duration corresponding to a TXOP limit defined by a wireless networking standard or a predefined TXOP duration agreed upon in the first BSS, whichever is shorter.

[0216] Turning now to Figure 25, a method 2500 will be described for providing expected TXOP duration information, in accordance with an example embodiment. The method 2500 may be performed by a wireless device (e.g., wireless device 104) that belongs to a first BSS to provide expected TXOP duration information to other BSSs.

[0217] At operation 2505, the wireless device determines an expected TXOP duration of a TXOP held by the first BSS.

[0218] At operation 2510, the wireless device transmits a control frame in a primary channel in the first BSS, wherein the control frame includes an indication of the expected TXOP duration, wherein the expected TXOP duration is longer than a duration indicated in a duration / identifier field included in the control frame. In an embodiment, the control frame is an initial control frame (ICF). In an embodiment, the control frame is an initial control response frame (CRF).Docket No. 1002P24024W01Client Matter No. P24-024WO1

[0219] In an embodiment, the control frame is a variant of a trigger frame, wherein the control frame includes a user info list field that includes a user info field for indicating the expected TXOP duration. In an embodiment, the user info field for indicating the expected TXOP duration includes an association identifier field that includes a value indicating that the user info field is for indicating the expected TXOP duration and a time information field that includes the indication of the expected TXOP duration. In an embodiment, the value indicating that the user info field is for indicating the expected TXOP duration is 2009. In an embodiment, the time information field has a length of 14 bits.

[0220] In an embodiment, the control frame is a variant of a block ACK frame, wherein the control frame includes a block ACK information field that includes a per AID and TID info field for indicating the expected TXOP duration. In an embodiment, the per AID and TID info field for indicating the expected TXOP duration includes an AID TID info field that includes a value indicating that the per AID and TID information field is for indicating the expected TXOP duration and a time information field that includes the indication of the expected TXOP duration. In an embodiment, the value indicating that the per AID and TID information field is for indicating the expected TXOP duration is 2009.

[0221] In an embodiment, at operation 2515, the wireless device determines an unavailability duration during which transmission and reception are unavailable in the first BSS and at operation 2520, the wireless device transmits a second control frame in the primary channel in the first BSS, wherein the control frame includes an indication of the unavailability duration.

[0222] Turning now to Figure 26, a method 2600 will be described for performing NPCA, in accordance with an example embodiment. The method 2600 may be performed by a wireless device (e.g., wireless device 104) that belongs to a first BSS.

[0223] At operation 2605, the wireless device overhears a control frame transmitted in a primary channel in the second BSS, wherein the control frame includes an indication of an expected TXOP duration of a TXOP held by the second BSS, wherein the expected TXOP duration is longer than a duration indicated in a duration / identifier field included in the control frame. In an embodiment, the control frame is an initial control frame (ICF). In an embodiment, the control frame is an initial control response frame (CRF).

[0224] In an embodiment, the control frame is a variant of a trigger frame, wherein the control frame includes a user info list field that includes a user info field for indicating the expected TXOP duration. In an embodiment, the user info field for indicating the expected TXOP duration includes an association identifier field that includes a value indicating that theDocket No. 1002P24024W01Client Matter No. P24-024WO1user info field is for indicating the expected TXOP duration and a time information field that includes the indication of the expected TXOP duration.

[0225] In an embodiment, the control frame is a variant of a block ACK frame, wherein the control frame includes a block ACK information field that includes a per AID and TID info field for indicating the expected TXOP duration. In an embodiment, the per AID and TID info field for indicating the expected TXOP duration includes an AID TID info field that includes a value indicating that the per AID and TID info field is for indicating the expected TXOP duration and a time information field that includes the indication of the expected TXOP duration.

[0226] At operation 2610, responsive to overhearing the control frame, the wireless device performs NPCA in a NPCA primary channel in the first BSS for the expected TXOP duration.

[0227] In an embodiment, at operation 2615, the wireless device overhears a second control frame transmitted in the primary channel in the second BSS, wherein the control frame includes an indication of an unavailability duration during which transmission and reception are unavailable in the second BSS. At operation 2620, responsive to overhearing the control frame, the wireless device refrains from performing NPCA in the first BSS for at least the unavailability duration.

[0228] An embodiment is a method performed by a wireless device belonging to a first BSS to perform NPCA. The method includes overhearing a PPDU exchange occurring in a primary channel in a second BSS, wherein the PPDU exchange includes a first PPDU, a second PPDU, and a third PPDU that are transmitted in succession in that order. The method further includes responsive to overhearing the PPDU exchange, performing NPCA in a NPCA primary channel in the first BSS using TXOP duration information obtained from the third PPDU.

[0229] Although many of the solutions and techniques provided herein have been described with reference to a WLAN system, it should be understood that these solutions and techniques are also applicable to other network environments, such as cellular telecommunication networks, wired networks, etc. In some embodiments, 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. In other embodiments, 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.Docket No. 1002P24024W01Client Matter No. P24-024WO1

[0230] In some cases, 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. For example, as 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.

[0231] Some portions of the preceding detailed descriptions have been presented in terms of algorithms and symbolic representations of operations on data bits within a computer memory. These algorithmic descriptions and representations are the ways used by those skilled in the data processing arts to most effectively convey the substance of their work to others skilled in the art. An algorithm is here, and generally, conceived to be a self-consi stent sequence of operations leading to a desired result. The operations are those requiring physical manipulations of physical quantities. Usually, though not necessarily, these quantities take the form of electrical or magnetic signals capable of being stored, combined, compared, and otherwise manipulated. It has proven convenient at times, principally for reasons of common usage, to refer to these signals as bits, values, elements, symbols, characters, terms, numbers, or the like.

[0232] It should be borne in mind, however, that all of these and similar terms are to be associated with the appropriate physical quantities and are merely convenient labels applied to these quantities. The present disclosure can refer to the action and processes of a computer system, or similar electronic computing device, that manipulates and transforms data represented as physical (electronic) quantities within the computer system's registers and memories into other data similarly represented as physical quantities within the computer system memories or registers or other such information storage systems.

[0233] 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. For example, 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),Docket No. 1002P24024W01Client Matter No. P24-024WO1random 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.

[0234] The algorithms and displays presented herein are not inherently related to any particular computer or other apparatus. Various general-purpose systems can be used with programs in accordance with the teachings herein, or it can prove convenient to construct a more specialized apparatus to perform the method. The structure for a variety of these systems will appear as set forth in the description below. In addition, the present disclosure is not described with reference to any particular programming language. It will be appreciated that a variety of programming languages can be used to implement the teachings of the disclosure as described herein.

[0235] 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). In some embodiments, 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.

[0236] In the foregoing specification, embodiments of the disclosure have been described with reference to specific example embodiments thereof. It will be evident that various modifications can be made thereto without departing from the broader spirit and scope of embodiments of the disclosure as set forth in the following claims. The specification and drawings are, accordingly, to be regarded in an illustrative sense rather than a restrictive sense.Docket No. 1002P24024W01Client Matter No. P24-024WO1

Claims

CLAIMSWhat is claimed is:

1. A method performed by a wireless device belonging to a first basic service set (BSS) to provide channel occupancy duration information to a second BSS to allow the second BSS to perform non-primary channel access (NPCA), the method comprising: determining an expected transmission opportunity (TXOP) duration of a TXOP held by the first BSS; and transmitting a physical layer protocol data unit (PPDU) in a primary channel in the first BSS, wherein a preamble of the PPDU includes a signal field that includes an indication of the expected TXOP duration, wherein the expected TXOP duration is longer than a duration indicated in a duration / identifier field included in a media access control (MAC) layer portion of the PPDU.

2. The method of claim 1, wherein the signal field is an ultra high reliability (UHR) signal field or a universal signal (U-SIG) field.

3. The method of claim 1, wherein the indication of the expected TXOP duration is included in a TXOP duration field included in the signal field.

4. The method of claim 1, wherein the signal field includes a TXOP duration field and an expected TXOP duration field, wherein the indication of the expected TXOP duration is included in the expected TXOP duration field.

5. The method of claim 1, wherein the duration indicated in the duration / identifier field indicates how long wireless devices should set their network allocation vectors (NAVs) for.

6. A method performed by a wireless device belonging to a first basic service set (BSS) to perform non-primary channel access (NPCA) based on overhearing a transmission in a second BSS, the method comprising: overhearing a physical layer protocol data unit (PPDU) transmitted in a primary channel in the second BSS, wherein a preamble of the PPDU includes a signal field that includes an indication of an expected transmission opportunity (TXOP) duration of a TXOP held by the second BSS, wherein the expected TXOP duration is longer than a duration indicated in a duration / identifier field included in a media access control (MAC) layer portion of the PPDU; andDocket No. 1002P24024W01Client Matter No. P24-024WO1responsive to overhearing the PPDU, performing NPCA in a NPCA primary channel in the first BSS for the expected TXOP duration.

7. The method of claim 6, wherein the signal field is an ultra high reliability (UHR) signal field or a universal signal (U-SIG) field.

8. The method of claim 6, wherein the indication of the expected TXOP duration is included in a TXOP duration field included in the signal field.

9. The method of claim 6, wherein the signal field includes a TXOP duration field and an expected TXOP duration field, wherein the indication of the expected TXOP duration is included in the expected TXOP duration field.

10. The method of claim 6, wherein the duration indicated in the duration / identifier field indicates how long wireless devices should set their network allocation vectors (NAVs) for.

11. A method performed by a wireless device belonging to a first basic service set (BSS) to provide channel occupancy duration information to a second BSS to allow the second BSS to perform non-primary channel access (NPCA), the method comprising: transmitting a physical layer protocol data unit (PPDU) in a primary channel in the first BSS, wherein a preamble of the PPDU includes a signal field that includes an indication that a transmission opportunity (TXOP) held by the first BSS will last longer than a TXOP duration indicated in the PPDU.

12. The method of claim 11, wherein the signal field is a ultra high reliability (UHR) signal field or a universal signal (U-SIG) field.

13. A method performed by a wireless device belonging to a first basic service set (BSS) to perform non-primary channel access (NPCA) based on overhearing a transmission in a second BSS, the method comprising: overhearing a physical layer protocol data unit (PPDU) transmitted in a primary channel in the second BSS, wherein a preamble of the PPDU includes a signal field that includes an indication that a transmission opportunity (TXOP) held by the second BSS will last longer than a TXOP duration indicated in the PPDU; determining that the TXOP held by the second BSS will last longer than the TXOP duration indicated in the PPDU based on the indication; andDocket No. 1002P24024W01Client Matter No. P24-024WO1responsive to determining that the TXOP held by the second BSS will last longer than the TXOP duration indicated in the PPDU, performing NPCA in a NPCA primary channel in the first BSS despite the TXOP duration indicated in the PPDU being shorter than a minimum NPCA duration threshold.

14. The method of claim 13, wherein the NPCA is performed for a duration corresponding to a TXOP limit defined by a wireless networking standard or a predefined TXOP duration agreed upon in the first BSS, whichever is shorter.

15. A method performed by a wireless device belonging to a first basic service set (BSS) to provide channel occupancy duration information to a second BSS to allow the second BSS to perform non-primary channel access (NPCA), the method comprising: determining an expected transmission opportunity (TXOP) duration of a TXOP held by the first BSS; and transmitting a control frame in a primary channel in the first BSS, wherein the control frame includes an indication of the expected TXOP duration, wherein the expected TXOP duration is longer than a duration indicated in a duration / identifier field included in the control frame.

16. The method of claim 15, wherein the control frame is an initial control frame.

17. The method of claim 15, wherein the control frame is an initial control response frame.

18. The method of claim 15, wherein the control frame is a variant of a trigger frame, wherein the control frame includes a user info list field that includes a user info field for indicating the expected TXOP duration.

19. The method of claim 18, wherein the user info field for indicating the expected TXOP duration includes an association identifier field that includes a value indicating that the user info field is for indicating the expected TXOP duration and a time information field that includes the indication of the expected TXOP duration.

20. The method of claim 19, wherein the value indicating that the user info field is for indicating the expected TXOP duration is 2009.Docket No. 1002P24024W01Client Matter No. P24-024WO121. The method of claim 19, wherein the time information field has a length of 14 bits.

22. The method of claim 15, wherein the control frame is a variant of a block acknowledgement (ACK) frame, wherein the control frame includes a block ACK information field that includes a per association identifier (AID) traffic identifier (TID) info field for indicating the expected TXOP duration.

23. The method of claim 22, wherein the per AID TID info field for indicating the expected TXOP duration includes an AID TID info field that includes a value indicating that the per AID and TID information field is for indicating the expected TXOP duration and a time information field that includes the indication of the expected TXOP duration.

24. The method of claim 23, wherein the value indicating that the per AID and TID information field is for indicating the expected TXOP duration is 2009.

25. The method of claim 15, further comprising: determining an unavailability duration during which transmission and reception are unavailable in the first BSS; and transmitting a second control frame in the primary channel in the first BSS, wherein the control frame includes an indication of the unavailability duration.

26. A method performed by a wireless device belonging to a first basic service set (BSS) to perform non-primary channel access (NPCA) based on overhearing a transmission in a second BSS, the method comprising: overhearing a control frame transmitted in a primary channel in the second BSS, wherein the control frame includes an indication of an expected transmission opportunity (TXOP) duration of a TXOP held by the second BSS, wherein the expected TXOP duration is longer than a duration indicated in a duration / identifier field included in the control frame; and responsive to overhearing the control frame, performing NPCA in a NPCA primary channel in the first BSS for the expected TXOP duration.

27. The method of claim 26, wherein the control frame is an initial control frame.

28. The method of claim 26, wherein the control frame is an initial control response frame.Docket No. 1002P24024W01Client Matter No. P24-024WO129. The method of claim 26, wherein the control frame is a variant of a trigger frame, wherein the control frame includes a user info list field that includes a user info field for indicating the expected TXOP duration.

30. The method of claim 29, wherein the user info field for indicating the expected TXOP duration includes an association identifier field that includes a value indicating that the user info field is for indicating the expected TXOP duration and a time information field that includes the indication of the expected TXOP duration.

31. The method of claim 26, wherein the control frame is a variant of a block acknowledgement (ACK) frame, wherein the control frame includes a block ACK information field that includes a per association identifier (AID) and traffic identifier (TID) information field for indicating the expected TXOP duration.

32. The method of claim 31, wherein the per AID and TID information field for indicating the expected TXOP duration includes an AID TID info field that includes a value indicating that the per AID and TID info field is for indicating the expected TXOP duration and a time information field that includes the indication of the expected TXOP duration.

33. The method of claim 26, further comprising: overhearing a second control frame transmitted in the primary channel in the second BSS, wherein the control frame includes an indication of an unavailability duration during which transmission and reception are unavailable in the second BSS; and responsive to overhearing the control frame, refraining from performing NPCA in the first BSS for at least the unavailability duration.

34. A method performed by a wireless device belonging to a first basic service set (BSS) to perform non-primary channel access (NPCA), the method comprising: overhearing a physical layer protocol data unit (PPDU) exchange occurring in a primary channel in a second BSS, wherein the PPDU exchange includes a first PPDU, a second PPDU, and a third PPDU that are transmitted in succession in that order; and responsive to overhearing the PPDU exchange, performing NPCA in a NPCA primary channel in the first BSS using TXOP duration information obtained from the third PPDU.Docket No. 1002P24024W01Client Matter No. P24-024WO135. A wireless device comprising: a radio frequency transceiver; a memory device storing a set of instructions; and a processor coupled to the memory device, wherein the set of instructions, when executed by the processor, causes the wireless device to perform the method of any one of claims 1-5.

36. A wireless device comprising: a radio frequency transceiver; a memory device storing a set of instructions; and a processor coupled to the memory device, wherein the set of instructions, when executed by the processor, causes the wireless device to perform the method of any one of claims 6-10.

37. A wireless device comprising: a radio frequency transceiver; a memory device storing a set of instructions; and a processor coupled to the memory device, wherein the set of instructions, when executed by the processor, causes the wireless device to perform the method of any one of claims 11-12.

38. A wireless device comprising: a radio frequency transceiver; a memory device storing a set of instructions; and a processor coupled to the memory device, wherein the set of instructions, when executed by the processor, causes the wireless device to perform the method of any one of claims 13-14.

39. A wireless device comprising: a radio frequency transceiver; a memory device storing a set of instructions; and a processor coupled to the memory device, wherein the set of instructions, when executed by the processor, causes the wireless device to perform the method of any one of claims 15-25.Docket No. 1002P24024W01Client Matter No. P24-024WO140. A wireless device comprising: a radio frequency transceiver; a memory device storing a set of instructions; and a processor coupled to the memory device, wherein the set of instructions, when executed by the processor, causes the wireless device to perform the method of any one of claims 16-33.Docket No. 1002P24024W01Client Matter No. P24-024WO1

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