Controlling cascading non-primary channel access (NPCA) operation

Abstract

Disclosed herein is a method performed by a wireless device to perform non-primary channel access (NPCA). The method includes responsive to detecting an overlapping basic service set (OBSS) physical layer protocol data unit (PPDU) in a primary channel of the BSS, transmitting a PPDU in a NPCA primary channel of the BSS, wherein the PPDU includes an indication that the PPDU is transmitted as part of a NPCA operation. The method further includes terminating the NPCA operation before OBSS transmission in the primary channel of the BSS is expected to end. The indication that the PPDU is transmitted as part of the NPCA operation may be included in a common information field of a trigger frame or a signal field of a preamble.

Description

SPECIFICATIONCONTROLLING CASCADING NON-PRIMARY CHANNEL ACCESS (NPCA) OPERATIONCROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of U.S. Provisional Application No. 63 / 719,436, filed November 12, 2024, titled “Method to mitigate cascading NPCA (Non-primary Channel Access) switching operation”, which is hereby incorporated by reference.TECHNICAL FIELD

[0002] The present disclosure generally relates to wireless communications, and more specifically, relates to controlling cascading non-primary channel access (NPCA) operation in a wireless network.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. TheIEEE 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 to simultaneously use multiple frequency bands and channels for enhanced performance andDocket No. 1002P24026W01Client Matter No. P24-026WO1reliability. Additionally, 802.11be 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 theseadvancements, 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 operation in a BSS can trigger NPCA operation in another BSS if the NPCA primary channel of the BSS is the same as (or overlaps with) the primary channel of the other BSS. Such cascading NPCA operation can affect the overall network throughput and latency.BRIEF DESCRIPTION OF THE DRAWINGS

[0007] 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.

[0008] 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.

[0009] Figure 2 is a schematic diagram of a wireless device, in accordance with some embodiments of the present disclosure.

[0010] Figure 3 A illustrates components of a wireless device configured to transmit data, in accordance with some embodiments of the present disclosure.Docket No. 1002P24026W01Client Matter No. P24-026WO1

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

[0012] Figure 4 illustrates interframe space (IFS) relationships, in accordance with some embodiments of the present disclosure.

[0013] Figure 5 illustrates a Carrier Sense Multiple Access with Collision Avoidance (CSMAZCA)-based frame transmission procedure, in accordance with some embodiments of the present disclosure.

[0014] 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.

[0015] 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.

[0016] Figure 8 illustrates an example of multi-user (MU) transmission in Orthogonal Frequency -Di vision Multiple Access (OFDMA), in accordance with some embodiments of the present disclosure.

[0017] 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.

[0018] Figure 10 is a diagram showing idle secondary channels being unused due to the primary channel being busy, according to some embodiments.

[0019] 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.

[0020] Figure 12 is a diagram showing a multi-BSS wireless network environment, according to some embodiments.

[0021] Figure 13 is a diagram showing a cascading NPCA operation , according to some embodiments.

[0022] Figure 14 is a diagram showing a NPCA operation indication being included in the signal field of the preamble, according to some embodiments.

[0023] Figure 15 is a diagram showing an EHT variant common information field format, according to some embodiments.

[0024] Figure 16 is a diagram showing an EHT capabilities element format, according to some embodiments.Docket No. 1002P24026W01Client Matter No. P24-026WO1

[0025] Figure 17 is a diagram showing an EHT MAC capabilities information field format, according to some embodiments.

[0026] Figure 18 is a diagram showing a frame exchange sequence during which an NPCA operation indication is transmitted, according to some embodiments.

[0027] Figure 19 is a diagram showing a cascading NPCA operation, according to some embodiments.

[0028] Figure 20 is a flow diagram of a method for performing NPCA, according to some embodiments.DETAILED DESCRIPTION

[0029] The present disclosure generally relates to wireless communications, and more specifically, relates to controlling cascading non-primary channel access (NPCA) operation in a wireless network.

[0030] NPCA operation in a particular BSS can trigger NPCA operation in other BSSs that use the NPCA primary channel of the particular BSS as their primary channel. For example, NPCA-capable AP / STAs of a first BSS that detect an OBSS transmission in the primary channel of the first BSS may switch to the NPCA primary channel of the first BSS and use the NPCA primary channel while the primary channel of the first BSS is expected to be occupied. Assume there is a second BSS that has a primary channel that is the same as the NPCA primary channel of the first BSS. If NPCA-capable AP / STAs of the second BSS detect the first BSS’s NPCA transmission (in the NPCA primary channel of the first BSS, which is the same as the primary channel of the second BSS), they may switch to using the NPCA primary channel of the second BSS. Such a situation where a NPCA operation in one BSS triggers NPCA operation in another BSS may be referred to as a cascading NPCA operation. It is important to consider whether cascading NPCA operation is beneficial in terms of overall network throughput and latency. The present disclosure describes a technique to limit or control cascading NPCA operation, as needed / desired.

[0031] With NPCA technology, a STA belonging to a BSS (MyBSS) operating in a primary channel of MyBSS can perform NPCA when it detects an OBSS PPDU transmitted in the primary channel of MyBSS. However, there is no way for the STA to determine whether the OBSS PPDU was transmitted by an OBSS operating in the same primary channel as MyBSS, was transmitted by an OBSS operating in channels that partially overlap with the primary channel of MyBSS, or was transmitted by an OBSS that switched channels due to NPCA operation.Docket No. 1002P24026W01Client Matter No. P24-026WO1

[0032] To effectively limit or control cascading NPCA operation, it is necessary to know whether an OBSS PPDU was transmitted as part of a NPCA operation or not. Thus, with embodiments disclosed herein, when a NPCA-capable AP / STA switches to its NPCA primary channel and transmits a PPDU (e.g., after performing a backoff procedure in the NPCA primary channel), it includes an indication in the PPDU that the PPDU is being transmitted as part of a NPCA operation (i.e., being transmitted in the NPCA primary channel of the transmitting NPCA-capable AP / STA). NPCA-capable AP / STAs that detect this PPDU in their primary channel can determine based on the NPCA operation indication included in the PPDU that the PPDU was transmitted as part of a NPCA operation, and decide whether to perform NPCA (which would be a cascading NPCA operation) or not depending on their configuration (e.g., depending on whether cascading NPCA operation is allowed or not).

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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 Docket No. 1002P24026W01Client Matter No. P24-026WO1devices 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 104 A) 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).

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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 Docket No. 1002P24026W01Client Matter No. P24-026WO1encoding 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 transmittingSPU 224, such as GI removal, Fourier Transform computation, and the like.

[0042] The RF transceiver 240 includes an RF transmitter 242 and an RF receiver 244. The RF transceiver 240 is configured to transmit first information received from the baseband processor 210 to the WLAN 100 (e.g., to another WLAN device 104 of the WLAN 100) and provide second information received from the WLAN 100 (e.g., from another WLAN device 104 of the WLAN 100) to the baseband processor 210.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] 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.Docket No. 1002P24026W01Client Matter No. P24-026WO1

[0048] The TxSP 324 includes an encoder 300, an interleaver 302, a mapper 304, an inverse Fourier transformer (TFT) 306, and a guard interval (GI) inserter 308.

[0049] 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.

[0050] The TxSP 324 may further include a scrambler for scrambling the input data before the encoding is performed by the encoder 300 to reduce the probability of long sequences of 0s or Is. 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.

[0051] 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.

[0052] 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.

[0053] 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.

[0054] 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.

[0055] 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 Docket No. 1002P24026W01Client Matter No. P24-026WO1perform 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.

[0056] When the TxSP 324 performs a MIMO or MU-MIMO transmission, some blocks before the spatial mapper may be provided for each user.

[0057] The GI inserter 308 prepends a GI to each symbol produced by the IFT 306. Each GI may include a Cyclic Prefix (CP) corresponding to a repeated portion of the end of the symbol that the GI precedes. The TxSP 324 may optionally perform windowing to smooth edges of each symbol after inserting the GI.

[0058] 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.

[0059] 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.

[0060] The RxSP 326 includes a GI remover 318, a Fourier transformer (FT) 316, a demapper 314, a deinterleaver 312, and a decoder 310.

[0061] 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.

[0062] 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.

[0063] 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.

[0064] 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,Docket No. 1002P24026W01Client Matter No. P24-026WO1the demapper 314 may further perform LDPC tone demapping before performing the constellation demapping.

[0065] 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.

[0066] 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 312 corresponding 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.

[0067] 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.

[0068] 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.

[0069] 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.

[0070] 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 Docket No. 1002P24026W01Client Matter No. P24-026WO1subcarriers, 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.

[0071] 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 Access Category (AC) ‘i’ (AIFS [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.

[0072] 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.

[0073] 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.

[0074] 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.

[0075] 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.

[0076] 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 Docket No. 1002P24026W01Client Matter No. P24-026WO1embodiment, 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.

[0077] 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 a DIFS or EIFS period. The WLAN device 104 may perform transmission or retransmission of the frame when the backoff timer reaches zero.

[0078] 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.

[0079] 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.

[0080] 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.

[0081] 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).

[0082] 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 Docket No. 1002P24026W01Client Matter No. P24-026WO1duration 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.

[0083] 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.

[0084] 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.

[0085] 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.

[0086] 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.

[0087] 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 Docket No. 1002P24026W01Client Matter No. P24-026WO1spectrum, (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.

[0088] 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.

[0089] 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.

[0090] 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 GHzband (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.

[0091] 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.

[0092] 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.

[0093] 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.Docket No. 1002P24026W01Client Matter No. P24-026WO1

[0094] Figure 7 provides a more detailed description of each field in the EHT PPDU frame, including their purposes and characteristics.

[0095] 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.

[0096] 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.

[0097] 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.

[0098] 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.

[0099] 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.

[0100] 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).Docket No. 1002P24026W01Client Matter No. P24-026WO1

[0101] 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.

[0102] 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. Upon receiving the Trigger frame, the STAs respond by sending their respective Uplink Orthogonal Frequency Division Multiple Access (UL OFDMA) TB PPDUs, utilizing the allocated resources within the specified 80 MHz bandwidth.

[0103] 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.

[0104] 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.

[0105] 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.

[0106] 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 Docket No. 1002P24026W01Client Matter No. P24-026WO1sequences 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.

[0107] 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 subpackets increases. The decoding process passes a cyclic redundancy check (CRC) and ends when the entire packet is decoded without error or the maximum number of subpackets is reached. 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.

[0108] 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.

[0109] 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 theIEEE 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.

[0110] 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 Docket No. 1002P24026W01Client Matter No. P24-026WO1schemes 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.

[0111] The operation of various AP coordination schemes has been discussed in the IEEE 802.1 Ibe and UHR standards:

[0112] 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.

[0113] Coordinated OFDMA (C-OFDMA): APs transmit on orthogonal frequency resources by coordinating and splitting the spectrum, enabling more efficient spectrum utilization.

[0114] Joint Transmission (JTX): Multiple APs transmit jointly to a given user simultaneously by sharing data between the APs.

[0115] Coordinated Spatial Reuse (C-SR): Multiple APs or STAs adjust their transmit power to reduce interference between APs.

[0116] By implementing these AP coordination schemes, WLAN systems can improve their overall throughput and efficiency by leveraging the cooperation between multiple APs.

[0117] 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.

[0118] Figure 10 is a diagram showing idle secondary channels being unused due to the primary channel being busy, according to some embodiments.

[0119] 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).Docket No. 1002P24026W01Client Matter No. P24-026WO1

[0120] 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).

[0121] 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 channel at 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).

[0122] 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 AP / STAs to switch to a predefined non-primary (secondary) channel when the primary 20 MHz channel is busy.

[0123] 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.

[0124] The diagram illustrates how the use of NPCA 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 AP / 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 AP / 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 AP / 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.Docket No. 1002P24026W01Client Matter No. P24-026WO1

[0125] Decisions regarding whether to switch channels forNPCA operations may require knowing additional information beyond knowing the OBSS channel occupancy duration. In this regard, each NPCA-capable AP / STA may maintain an OBSS information set that it can reference when making channel switching decisions for NPCA. The OBSS information set may include information regarding OBSSs that the NPCA-capable STA has learned about based on overhearing OBSS PPDUs (PPDUs transmitted by OBSSs). The NPCA-capable AP / STA may compare the information obtained from an overheard and decoded OBSS PPDU with the information in its OBSS information set to decide whether it should switch channels to perform NPCA. The OBSS information set may be organized / structured in any suitable format. In the present disclosure, the OBSS information set is shown as being organized / structured in a table format (with rows and columns). However, it should be appreciated that an OBSS information set can be organized / structured in a different format (e.g., as a list).

[0126] For the sake of simplifying the explanation, it is assumed that the OBSS information set is maintained / updated based on information obtained from downlink (DL) PPDUs transmitted by OBSS APs. It will be appreciated, however, that the OBSS information set can also be maintained / updated based on information obtained from uplink (UL) PPDUs transmitted by OBSS non-AP STAs. Table 1 shows an example of an OBSS information set that can be maintained based on information obtained from OBSS PPDUs. As shown in Table 1, The OBSS information set may include the ID of the OBSS (e.g., BSS color or OBSSID) or the ID of the AP that operates the OBSS, the operating bandwidth of the OBSS, the primary 20 MHz channel number for the OBSS, and potentially other information. Maintaining this information allows a NPCA-capable AP / STA to determine whether NPCA can be performed when overhearing PPDUs transmitted by the OBSSs listed in the OBSS information set.

[0127] In an embodiment, a NPCA-capable AP / STA only performs NPCA if the overheard OBSS PPDU is transmitted by an OBSS listed in its OBSS information set. While it is possible to decode an arbitrary OBSS PPDU transmitted by an OBSS that is not listed in the OBSS information set and to perform NPCA during the NAV duration indicated in the OBSS PPDU (primary channel occupancy duration), this may cause the issue of not knowing whether the peer STAs will also perform NPCA. As such, it may be important to maintain an OBSS information set.Docket No. 1002P24026W01Client Matter No. P24-026WO1

[0128] Table 1

[0129] An AP and its associated STAs may exchange their OBSS information sets with each other (so that they are synchronized). In an embodiment, the information can be included in management frames such as probe request / response frames and / or action frames. In an embodiment, the information can be exchanged during an association process. In an embodiment, the AP provides the information in the information elements (IES) of beacon frames.

[0130] Various terminology that will be used in the present disclosure are defined below.

[0131] As used herein, “primary channel” may refer to a channel (e.g., a 20 MHz channel) that is designated as the baseline channel for a BSS (the channel that is used for performing normal (non-NPCA) operation.

[0132] As used herein, “NPCA primary channel” may refers to a temporary primary channel (e.g., a 20 MHz channel) that is used for performing NPCA operation in a BSS (the channel that NPCA-capable AP / STAs belonging to the BSS switch to for performing NPCA operation).

[0133] As used herein, “target BSS” or “MyBSS” may refers to the BSS to which the main AP / STAs involved in the explanation belong.

[0134] As used herein, “target BSS STA” may refers to a STA that belongs to the target BSS.

[0135] As used herein “target BSS NPCA STA” or “target NPCA STA” may refer to a target BSS STA that is capable of performing NPCA.

[0136] As used herein, “NPCA AP STA” or “NPCA AP” may refer to an AP STA that is capable of performing NPCA.

[0137] As used herein, “NPCA non-AP STA” or “NPCA STA” may refers to a non-AP STA that is capable of performing NPCA.

[0138] As used herein, “NPCA operating bandwidth” may refer to the operating bandwidth that a NPCA AP / STA uses to perform NPCA.

[0139] As used herein, “OBSS NPCA STA” may refer to a STA that belongs to an OBSS with respect to the target BSS and that is capable of performing NPCA.Docket No. 1002P24026W01Client Matter No. P24-026WO1

[0140] The use of NPCA can increase spectral utilization by making use of otherwise unused secondary channels when the primary channel is busy.

[0141] Careful consideration is needed regarding whether target BSS NPCA AP / STAs should perform NPCA for all OBSS PPDUs detected in the primary channel of the target BSS. Cases where an OBSS PPDU can occupy the primary channel of the target BSS can be categorized as follows: (1) OBSS has the same primary channel as the target BSS; (2) OBSS has an operating bandwidth that partially overlaps with the primary channel of the target BSS; (3) OBSS has a NPCA primary channel that is the same as the primary channel of the target BSS (assuming the OBSS supports NPCA operation); and (4) OBSS has a NPCA operating bandwidth that partially overlaps with the primary channel of the target BSS (assuming the OBSS supports NPCA operation). It may not always be beneficial for the target BSS NPCA AP / STA to perform NPCA for every OBSS PPDU occurring in all these cases.

[0142] In cases (1) and (2) mentioned above, the OBSS AP / STAs operate in the target BSS primary channel and continuously sense the channel during idle states. Consider the transmissions by OBSS NPCA AP / STAs that have a NPCA operating bandwidth that overlaps with (or encompasses) the target BSS’ s primary channel, as described in cases 3 and 4 above. In these cases, the OBSS AP / STAs may intermittently switch to the target BSS’s primary channel for NPCA operation. Such events may not always occur (e.g., they are sporadic). From the perspective of the target BSS NPCA AP / STAs, it is reasonable to expect that the OBSS NPCA AP / STAs will switch back to their primary channel after the OBSS PPDU duration ends (e.g., the PPDU caused by cases (3) and (4) is finished transmitting). Consequently, it can be anticipated that the congestion in the target BSS’s NPCA primary channel will naturally subside on its own.

[0143] Also, performing NPCA for all detected OBSS PPDUs increases the frequency of NPCA switching for target BSS AP / STAs. While NPCA operation can improve channel utilization, frequent switching attempts require multiple AP / STAs to consume power and incur delays for channel switching and switching back. Also, the channel switching inevitably requires stabilization times for the analog and baseband components. Also, there is no guarantee that the NPCA primary channel will be available at the time of switching. Thus, frequent channel switching can reduce power efficiency and degrade the overall performance of the target BSS. Moreover, the channel switching operation (to the NPCA primary channel) of the target BSS NPCA AP / STAs may trigger further channel switching in OBSS AP / STAs that use the target BSS’s NPCA primary channel as their primary channel.Docket No. 1002P24026W01Client Matter No. P24-026WO1

[0144] From a slightly different perspective, the NPCA operation of target BSS NPCA AP / STAs in the NPCA primary channel may negatively impact the backoff privilege acquisition of OBSS STAs that use the target BSS’s NPCA primary channel as their primary channel. This is because target BSS NPCA STAs with a buffer unit (BU) may attempt to occupy the channel, thereby increasing the number of contenders participating in the network.

[0145] Thus, the NPCA operation of each BSS can trigger the NPCA operation of other BSSs. In the present disclosure, such a scenario is referred to as cascading NPCA operation. An example environment / scenario in which cascading NPCA operation can occur is described with reference to Figure 12 and Figure 13.

[0146] Figure 12 is a diagram showing a multi-BSS wireless network environment, according to some embodiments.

[0147] As shown in the diagram, the wireless network environment may include a first AP (“API”) operating a first BSS (“BSS1”), a second AP (“AP2”) operating a second BSS (“BSS2”), and a third AP (“AP3”) operating a third BSS (“BSS3”). The coverage area of one BSS may overlap at least partially with the coverage area of another BSS. For example, in the example shown in the diagram, the coverage areas of BSS1 and BSS3 may overlap. Also, the primary channel of a BSS may overlap with the NPCA primary channel of another BSS. For example, the primary channel of BSS2 may be the same as the NPCA primary channel of BSS 1 and the primary channel of BSS3 may be the same as the NPCA primary channel of BSS2.

[0148] Figure 13 is a diagram showing a cascading NPCA operation , according to some embodiments.

[0149] The diagram shows an example of where the NPCA operation in each BSS can trigger NPCA operation in another BSS in a sequential manner. For example, BSS1 AP / STAs that detect an OBSS PPDU transmitted in the primary channel of BSS 1 may switch to the NPCA primary channel of BSS1 and perform NPCA. BSS2 AP / STAs may detect BSSl’s NPCA operation in the primary channel of BSS2 (which is the same as the NPCA primary channel of BSS1) and switch to the NPCA primary channel of BSS2 and perform NPCA. BSS3 AP / STAs may detect BSS2’s NPCA operation in the primary channel of BSS3 (which is the same as the NPCA primary channel of BSS2) and switch to the NPCA primary channel of BSS3 and perform NPCA. BSS3 AP / STAs may switch back to the primary channel of BSS3 before the NPCA operation of BSS2 is over. BSS2 AP / STAs may switch back to the primary channel of BSS2 before the NPCA operation of BSS1 is over. BSS1 AP / STAs may switch back to the primary channel of BSS1 before the OBSS transmission opportunity (TXOP) is over. SuchDocket No. 1002P24026W01Client Matter No. P24-026WO1sequential channel switching (and switching back) may negatively impact the overall network throughput, and this scenario should be carefully limited / controlled.

[0150] OBSS NPCA AP / STAs may switch to the primary channel of the target BSS (MyBSS) and occupy the channel. The target BSS NPCA AP / STAs that detect this may switch to the NPCA primary channel of the target BSS to perform NPCA. Similarly, the NPCA channel switching and channel occupation by the target BSS NPCA AP / STAs can affect OBSSs that use the target BSS’ s NPCA primary channel as their primary channel. Since OBSS AP / STAs in such situations can also sequentially perform NPCA, a method to restrict and control these situations is needed. It should be considered whether such cascading NPCA operation is beneficial in terms of overall network throughput and latency. Embodiments provide a way to restrict or control situations where the NPCA operation in one BSS triggers NPCA operation in other BSSs due to such interactions.

[0151] With NPCA technology, an AP / STA belonging to a target BSS operating in a primary channel can perform NPCA when it detects an OBSS PPDU transmitted in the primary channel of the target BSS. However, there is no way for the target BSS AP / STA to determine whether the OBSS PPDU was transmitted by an OBSS operating in the same primary channel as MyBSS, was transmitted by an OBSS operating in channels that partially overlap with the primary channel of MyBSS, or was transmitted by an OBSS that switched channels for NPCA operation.

[0152] To be able to restrict or control cascading NPCA operation, it is necessary for AP / STAs to identify whether an OBSS PPDU was transmitted as part of a NPCA operation. To allow this, in an embodiment, a NPCA AP / STA that transmits a PPDU in its NPCA primary channel (after performing a backoff procedure) inserts an indication in the PPDU that the PPDU is being transmitted as part of a NPCA operation. The indication, which may also be referred to as a NPCA operation indication, may be inserted in all or some PPDUs transmitted in the NPCA primary channel as part of the NPCA operation.

[0153] The NPCA operation indication can be included in the signal field of the preamble (e.g., in a UHR signal field) or in one of the MAC layer fields. NPCA APs / STAs that receive / detect the NPCA operation indication can decide, based on predetermined rules, whether to perform (cascading) NPCA or not.

[0154] Even if a PPDU that includes a NPCA operation indication is detected in the primary channel of the target BSS, the target BSS can still perform NPCA. In such case, the target BSS NPCA AP / STA, which switched to its NPCA primary channel for NPCA operation, may affect other BSSs. To mitigate this congestion, in an embodiment, untriggered transmission may be Docket No. 1002P24026W01Client Matter No. P24-026WO1prohibited when performing NPCA operation in the NPCA primary channel. That is, NPCA non-AP STAs may only transmit in the NPCA primary channel when they are triggered by a NPCA AP (e.g., receive a trigger frame from the NPCA AP). This approach may reduce the number of STAs performing backoff contention in the NPCA primary channel, thereby alleviating congestion caused by multiple STAs attempting to acquire the channel.

[0155] Figure 14 is a diagram showing a NPCA operation indication being included in the signal field of the preamble, according to some embodiments.

[0156] As shown in the diagram, a PPDU may include a PHY preamble 1440 that includes various fields such as a STF field 1405, a L-LTF field 1410, a U-SIG field 1415, and a SIG CRC field 1425. The PPDU may also include a MPDU 1430. The U-SIG field 1415 (e.g., which may be a UHR-SIG field) may include a NPCA operation indication 1420 to indicate that the PPDU is being transmitted as part of a NPCA operation.

[0157] In an embodiment, the NPCA operation indication is included in a MAC field. For example, the NPCA operation indication may be included in a common information field of a MPDU such as the EHT variant common information field shown in Figure 15.

[0158] Figure 15 is a diagram showing an EHT variant common information field format, according to some embodiments. The particular field formats shown in the diagrams are provided to illustrate an embodiment. It should be appreciated that other embodiments can use different field formats. For sake of conciseness / brevity, all of the fields are not described in detail herein. Only the fields that are considered relevant for understanding embodiments are described in further detail. Unless indicated otherwise, the fields can be interpreted in accordance with the IEEE 802.11 wireless networking standard.

[0159] As shown in the diagram, the EHT variant common information field includes a trigger type field 1502 (4 bits), a UL length field 1504 (12 bits), a more TF field 1506 (1 bit), a CS required field 1508 (1 bit), a UL BW field 1510 (2 bits), a GI and HE / EHT-LTF type / triggered TXOP sharing mode field 1512 (2 bits), a reserved field 1514 (1 bit), a number of HE / EHT-LTF symbols field 1516, a reserved field 1518 (1 bit), aLDPC extra symbol segment field 1520 (1 bit), an AP Tx power field 1522 (6 bits), a pre-FEC padding factor field 1524 (2 bits), a PE disambiguity field 1526 (1 bit), a UL spatial reuse field 1528 (16 bits), a reserved field 1530 (1 bit), HE / EHT P160 field 1532 (1 bit), a special user info field flag field 1534 (1 bit), a EHT reserved field 1536 (7 bits), a reserved field 1538 (1 bit), and a trigger dependent common info field 1540 (variable length).

[0160] In an embodiment, one of the reserved bits included in the EHT variant common information field can be used to provide the NPCA operation indication. For example, bit B22Docket No. 1002P24026W01Client Matter No. P24-026WO1of the EHT variant common information field can be used for this purpose (e.g., bit B22 being set to a value of binary ‘ 1 ’ may indicate that the PPDU is being transmitted as part of NPCA operation and bit B22 being set to a value of binary ‘0’ may indicate that the PPDU is not being transmitted as part of NPCA operation, although the opposite convention is also possible).

[0161] In an embodiment, if a UHR variant common information field is defined, the NPCA operation indication can be included in one of the subfields of the UHR variant common information field.

[0162] The behavior of a NPCA AP / STA upon receiving a NPCA operation indication can be configurable. For example, the behavior can be agreed upon during an association phase between an AP and its associated STAs (e.g., during capabilities exchange). Additionally or alternatively, the behavior can be shared between the AP and STAs using periodic updates of a NPCA information element. For example, information about the behavior can be indicated in a capabilities information field (e.g., the MAC capabilities information field shown in Figure 17) or in fields of management information elements (e.g., specified in the wireless networking standard).

[0163] Figure 16 is a diagram showing an EHT capabilities element format, according to some embodiments.

[0164] As shown in the diagram, the EHT capabilities element may include an element ID field 1605 (1 octet), a length field 1610 (1 octet), an element ID extension field 1615 (1 octet), an EHT MAC capabilities information field 1620 (2 octets), an EHT PHY capabilities information field 1625 (9 octets), a supported EHT-MCS and NSS set field 1630 (variable length), and an EHT PPE threshold field 1635 (variable length). An example format of the EHT MAC capabilities information field 1620 is shown in Figure 17.

[0165] Figure 17 is a diagram showing an EHT MAC capabilities information field format, according to some embodiments.

[0166] As shown in the diagram, the EHT MAC capabilities information field format may include an EPCS priority access support field 1705 (1 bit), an EHT OM control support field 1710 (1 bit), a TXS mode 1 support field 1715 (1 bit), a TXS mode 2 support field 1720 (1 bit), a restricted TWT support field 1725 (1 bit), a SCS traffic description support field 1730 (1 bit), a maximum MPDU length field 1735 (2 bits), a maximum A-MPDU length exponent extension field 1740 (1 bit), an EHT TRS support field 1745 (1 bit), a TXOP return support in TXS mode 2 field 1750 (1 bit), a two BQRs support field 1755 (1 bit), an EHT link adaptation support field 1760 (2 bits), an unsolicited EPCS priority access parameter update field 1765 (1 bit), and a reserved field 1770 (1 bit).Docket No. 1002P24026W01Client Matter No. P24-026WO1

[0167] The behavior of a NPCA AP / STA upon receiving a NPCA operation indication can be configured / indicated using reserved bits included in the capabilities information field. For example, for UHR, a UHR MAC capabilities information field can be defined that has a similar format as the EHT MAC capabilities information field. The UHR MAC capabilities information field may include a “cascading NPCA mode” field or similar field composed of two bits. The meaning of the two bits can be as follows: (1) ‘00’ : cascading NPCA operation is prohibited; (2) ‘01’: cascading NPCA operation is allowed only when the target BSS’s primary channel is the same as the OBSS’s NPCA primary channel; (3) ‘10’: cascading NPCA operation is allowed in all situations where a NPCA operation indication is received; and (4) ‘ 11’ : reserved.

[0168] In an embodiment, if a received OBSS PPDU includes a NPCA operation indication, the cascading NPCA mode is not set to a value of ‘00’ (i.e., cascading NPCA operation is not prohibited), and NPCA operation is allowed, then the target BSS AP / STA may perform cascading NPCA operation.

[0169] When the aforementioned preconditions are met, the target BSS NPCA AP / STA may perform cascading NPCA operation upon receiving an NPCA operation indication from an OBSS. However, due to channel access attempts by the target BSS NPCA AP / STAs that have switched to the NPCA primary channel, the target BSS’s NPCA primary channel may become congested for a period of time. To alleviate this congestion, in an embodiment, NPCA non-AP STAs that perform NPCA under such conditions can be restricted from untriggered transmissions. The prohibition / restriction of untriggered transmissions during NPCA operation can be configured / indicated in a capabilities information field or management information elements. For example, the AP may decide the operation mode (e.g., whether untriggered transmission is prohibited) and notify each STAs regarding the operation mode during the association process with the STA. Additionally or alternatively, the AP may inform its associated STAs regarding the operation mode through management frames.

[0170] Figure 18 is a diagram showing a frame exchange sequence during which an NPCA operation indication is transmitted, according to some embodiments. The frame exchange sequence is shown / described from the perspective of BSS1.

[0171] As shown in the diagram, if BSS 1 detects OBSS PPDU 1805 in its primary channel (channel #1 in this example), BSS1 may switch to BSSl’s NPCA primary channel (channel #2 in this example). At time tl, BSS1 may perform an EDCA backoff in the NPCA primary channel. After performing the EDCA backoff, at time t2, BSS1 may transmit PPDU 1815 in the NPCA primary channel. PPDU 1815 may include an indication (NPCA operation indication) that it is being transmitted as part of a NPCA operation. In an embodiment, PPDU 1815 may Docket No. 1002P24026W01Client Matter No. P24-026WO1carry an initial control frame (ICF). In an embodiment, if PPDU 1815 carries a trigger frame, the NPCA operation indication may be included in a common information field of the trigger frame. If PPDU 1815 is a UHR PPDU, the NPCA operation indication may be included in a UHR-SIG field included in the preamble of PPDU 1815. BSS1 may transmit further PPDUs such as PPDU 1820 (e.g., which may be an initial control response (ICR) frame). BSS1 may perform a frame exchange 1825 during the OBSS TXOP duration and switch back to B SSI’s primary channel before the OBSS TXOP duration ends at time t3 (e.g., before OBSS PPDU frame exchange 1810 ends).

[0172] A NPCA non-AP STA may transmit a ICF after switching to the NPCA primary channel, assuming that untriggered transmission by non-AP STAs is allowed during NPCA operation. If the ICF is assumed to be a block acknowledgment request (BAR) frame (which is a general control frame, and not a trigger frame), the BA information field of the BAR frame may include the NPCA operation indication. Alternatively, if the UHR PPDU format is used, the UHR SIG field can include the NPCA operation indication.

[0173] Now, consider a scenario where a NPCA AP / STA belonging to a different BSS (BSS2) uses the NPCA primary channel of BSS 1 (channel #2) as its primary channel and detects PPDU 1815 mentioned above that includes the NPCA operation indication. This may result in a cascading NPCA operation as shown in Figure 19.

[0174] Figure 19 is a diagram showing a cascading NPCA operation, according to some embodiments.

[0175] As shown in the diagram, from the perspective of BSS1, if BSS1 detects OBSS PPDU 1905 in its primary channel (channel #1 in this example), BSS1 may switch to BSSl’s NPCA primary channel (channel #2 in this example). At time tl, BSS1 may perform an EDCA backoff in its NPCA primary channel. After performing the EDCA backoff, at time t2, BSS1 may transmit PPDU 1915 in the NPCA primary channel. PPDU 1915 may include an indication that it is being transmitted as part of a NPCA operation. In an embodiment, PPDU 1915 may carry an ICF. BSS1 may transmit further PPDUs such as PPDU 1920 (e.g., which may be an ICR frame). BSS1 may perform a frame exchange 1925 during the OBSS TXOP duration and switch back to BSSl’s primary channel before the OBSS TXOP duration ends at time t3 (e.g., before OBSS PPDU frame exchange 1910 ends).

[0176] From the perspective of BSS2, at time t2, BSS2 may detect PPDU 1915 (which is transmitted by BSS1 in BSS2’s primary channel (which is BSSl’s NPCA primary channel)). If BSS2 allows cascading NPCA operation, BSS2 may perform NPCA when OBSS transmission occurs in BSS2’s primary channel. For example, at time t3, BSS2 may transmit PPDU 1940 (in Docket No. 1002P24026W01Client Matter No. P24-026WO1BSS2’s NPCA primary channel, which is channel #3 in this example) that includes a NPCA operation indication. BSS2 may also perform a frame exchange sequence 1945 during the OBSS TXOP duration (e.g., BSSl’s TXOP duration) and switch back to BSS2’s primary channel before the OBSS TXOP duration ends at time t3 (e.g., before OBSS PPDU frame exchange 1935 ends). Alternatively, if BSS2 does not allow cascading NPCA operation, BSS2 may choose not to perform NPCA after detecting PPDU 1915 (and the NPCA operation indication included therein).

[0177] The BSS2 AP and STAs may configure the cascading NPCA operation setting / mode (whether cascading NPCA operation is allowed) during an association phase or through notification from the AP. During the association phase, the AP may provide information in a NPCA information element field regarding whether (and in what circumstances) NPCA operation can be performed when a NPCA operation indication is received from an OBSS.

[0178] For NPCA AP / STAs, it is important for both the AP and non-AP STAs to switch to the NPCA primary channel at the same time. Therefore, it is more efficient if NPCA AP / STAs have information about whether they can perform NPCA when detecting a transmission from a specific OBSS. In this scenario, it is assumed that NPCA AP / STAs maintain an OBSS information set (e.g., an OBSS table / list) that helps them determine whether they can perform NPCA upon detecting a PPDU transmitted by a particular OBSS. Also, it is assumed that the information included in this OBSS information set is shared between the AP and its associated STAs, and that NPCA is performed only when there is mutual information about the same OBSS.

[0179] When a target BSS AP / STA receives an OBSS PPDU in its primary channel that includes a NPCA operation indication and cascading NPCA operation is not allowed in the target BSS, the target BSS AP / STA should determine that this transmission from the OBSS does not meet the conditions for performing NPCA. This approach fundamentally blocks cascading NPCA operation. In this scenario, if NPCA AP / STAs maintain a list of OBSSs, they may avoid updating the particular OBSS in the list. As a result, even if an OBSS PPDU is detected in the primary channel of the target BSS, the target BSS NPCA AP / STAs may ignore it (not perform NPCA) since it does not meet the conditions for performing NPCA.

[0180] The present disclosure considers the situation where OBSS PPDUs transmitted as part of a NPCA operation occupy the primary channel of a target BSS. From the perspective of the target BSS, OBSS PPDUs transmitted as part of a NPCA operation can be considered as aperiodic and intermittent transmissions resulting from temporary channel switching actions. As such, target BSS NPCA AP / STAs should have the flexibility to decide whether to use such Docket No. 1002P24026W01Client Matter No. P24-026WO1OBSS PPDUs as a basis for performing NPCA or not. Embodiments disclosed herein provide options for determining what actions to take in such scenarios, providing a more flexible protocol. Also, embodiments help secure a margin to consider both the power consumption of wireless devices and channel utilization.

[0181] Turning now to Figure 20, a method 2000 will be described for performing NPCA, in accordance with an example embodiment. The method 2000 may be performed by a wireless device (e.g., wireless device 104) belonging to a BSS.

[0182] Additionally, although shown in a particular order, in some embodiments the operations of the method 2000 may be performed in a different order. For example, although the operations of the method 2000 are shown in a sequential order, some of the operations may be performed in partially or entirely overlapping time periods.

[0183] At operation 2005, the wireless device detects an OBSS PPDU in a primary channel of the BSS.

[0184] In an embodiment, at operation 2010, the wireless device determines whether the primary channel of the BSS matches (is the same as) a primary channel in which the OBSS PPDU is transmitted. If the primary channel of the BSS matches the primary channel in which the OBSS PPDU is transmitted, the flow may proceed to operation 2020. Otherwise, if the primary channel of the BSS does not match the primary channel in which the OBSS PPDU is transmitted, the flow may proceed to operation 2015, at which the wireless device decides not to perform NPCA.

[0185] In an embodiment, at operation 2020, the wireless device determines, based on a NPCA operation indicator included in OBSS PPDU, whether the OBSS PPDU is transmitted as part of an OBSS NPCA operation. If the OBSS PPDU is transmitted as part of the OBSS NPCA operation (e.g., the NPCA operation indicator being set to a value of binary ‘1’ may be considered as being a NPCA operation indication indicating that the OBSS PPDU is transmitted as par), the flow may move to operation 2025. In an embodiment, at operation 2025, the wireless device determines whether cascading NPCA operation is allowed. If cascading NPCA operation is not allowed, the flow may move to operation 2015, at which the wireless device decides not to perform NPCA. Otherwise, if cascading NPCA operation is allowed, the flow may move to operation 2030. In an embodiment, the wireless device receives, during an association phase, an indication that cascading NPCA operation is allowed (or not allowed). In an embodiment, the indication that cascading NPCA operation is allowed (or not allowed) is included in a MAC capabilities information field received during the association phase.Returning to operation 2020, if the wireless device determines that the OBSS PPDU is not Docket No. 1002P24026W01Client Matter No. P24-026WO1transmitted as part of the OBSS NPCA operation (e.g., the NPCA operation indicator being set to a value of binary ‘0’ may be considered as an absence of an NPCA operation indication and thus an indication that the OBSS PPDU is not transmitted as part of the OBSS NPCA operation), the flow may move to operation 2030.

[0186] At operation 2030, the wireless device transmits a PPDU in a NPCA primary channel of the BSS, wherein the PPDU includes an indication that the PPDU is transmitted as part of a NPCA operation. In an embodiment, the PPDU includes a MPDU, wherein the indication that the PPDU is transmitted as part of the NPCA operation is included in the MPDU. In an embodiment, the MPDU includes a common information field, wherein the indication that the PPDU is transmitted as part of the NPCA operation is included in the common information field. For example, the indication that the PPDU is transmitted as part of the NPCA operation may be included in bit B22 of the common information field. In an embodiment, the common information field is an EHT variant common information field or a UHR variant common information field. In an embodiment, the MPDU includes an initial control frame. In an embodiment, the PPDU includes a preamble that includes a signal field, wherein the indication that the PPDU is transmitted as part of the NPCA operation is included in the signal field. In an embodiment, the signal field is a UHR signal field.

[0187] In an embodiment, the primary channel of the BSS and the primary channel in which the OBSS PPDU is transmitted do not need to match to perform NPCA. For example, the wireless device may transmit the PPDU (perform NPCA) if a secondary channel in which the OBSS PPDU is transmitted overlaps with (or encompasses) the primary channel of the BSS.

[0188] In an embodiment, as shown in block 2035, untriggered NPCA transmissions are not allowed during cascading NPCA operation or during both (regular / non-cascading) NPCA operation and cascading NPCA operation. In an embodiment, the wireless device receives, during an association phase, an indication that untriggered transmissions are not allowed (or allowed) during the NPCA operation.

[0189] At operation 2040, the wireless device terminates the NPCA operation before OBSS transmission in the primary channel of the BSS is expected to end.

[0190] 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 Docket No. 1002P24026W01Client Matter No. P24-026WO1more 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.

[0191] 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.

[0192] 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-consistent 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.

[0193] 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.

[0194] 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 outDocket No. 1002P24026W01Client Matter No. P24-026WO1the computer-implemented methods described herein in response to its processor executing a computer program (e.g., a sequence of instructions) contained in a memory or other non-transitory machine-readable storage medium. Such a computer program can be stored in a computer readable storage medium, such as, but not limited to, any type of disk including floppy disks, optical disks, CD-ROMs, and magnetic-optical disks, read-only memories (ROMs), random access memories (RAMs), EPROMs, EEPROMs, magnetic or optical cards, or any type of media suitable for storing electronic instructions, each coupled to a computer system bus.

[0195] 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.

[0196] 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.

[0197] 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. 1002P24026W01Client Matter No. P24-026WO1

Claims

CLAIMSWhat is claimed is:

1. A method performed by a wireless device belonging to a basic service set (BSS) to perform non-primary channel access (NPCA), the method comprising:responsive to detecting an overlapping basic service set (OBSS) physical layer protocol data unit (PPDU) in a primary channel of the BSS, transmitting a PPDU in a NPCA primary channel of the BSS, wherein the PPDU includes an indication that the PPDU is transmitted as part of a NPCA operation; andterminate the NPCA operation before OBSS transmission in the primary channel of the BSS is expected to end.

2. The method of claim 1, wherein the PPDU includes a media access control protocol data unit (MPDU), wherein the indication that the PPDU is transmitted as part of the NPCA operation is included in the MPDU.

3. The method of claim 2, wherein the MPDU includes a common information field, wherein the indication that the PPDU is transmitted as part of the NPCA operation is included in the common information field.

4. The method of claim 3, wherein the indication that the PPDU is transmitted as part of the NPCA operation is included in bit B22 of the common information field.

5. The method of claim 3, wherein the common information field is an extremely high throughput (EHT) variant common information field or an ultra high reliability (UHR) variant common information field.

6. The method of claim 2, wherein the MPDU includes an initial control frame.

7. The method of claim 1, wherein the PPDU includes a preamble that includes a signal field, wherein the indication that the PPDU is transmitted as part of the NPCA operation is included in the signal field.

8. The method of claim 7, wherein the signal field is an ultra high reliability (UHR) signal field.Docket No. 1002P24026W01Client Matter No. P24-026WO19. The method of claim 1, wherein the PPDU is transmitted further responsive to a determination that the primary channel of the BSS matches a primary channel in which the OBSS PPDU is transmitted.

10. The method of claim 1, wherein the PPDU is transmitted further responsive to a determination that a secondary channel in which the OBSS PPDU is transmitted overlaps with the primary channel of the BSS.

11. The method of claim 1, wherein untriggered transmissions are not allowed during the NPCA operation.

12. The method of claim 1, further comprising:receiving, during an association phase, an indication that untriggered transmissions are not allowed during the NPCA operation.

13. The method of claim 1, further comprising:determining whether the OBSS PPDU is transmitted as part of an OBSS NPCA operation based on an NPCA operation indicator included in the OBSS PPDU; andresponsive to determining that the OBSS PPDU is transmitted as part of the OBSS NPCA operation, determining whether cascading NPCA operation is allowed, wherein the PPDU is transmitted further responsive to a determination that cascading NPCA operation is allowed.

14. The method of claim 13, further comprising:receiving, during an association phase, an indication that cascading NPCA operation is allowed.

15. The method of claim 14, wherein the indication that cascading NPCA operation is allowed is included in a media access control (MAC) capabilities information field received during the association phase.

16. A wireless device comprising:a radio frequency transceiver;a memory device storing a set of instructions; andDocket No. 1002P24026W01Client Matter No. P24-026WO1a 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 1-15.Docket No. 1002P24026W01Client Matter No. P24-026WO1

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