Controlling non-primary channel access (NPCA) during multi-access point coordination

Abstract

Disclosed herein is a method performed by a first access point (AP) operating a first basic service set (BSS) to control non-primary channel access (NPCA) operation in the first BSS when the first AP performs multi-AP coordination with a second AP operating a second BSS that is different from the first BSS. The method includes transmitting an indication of whether NPCA is allowed in the first BSS during multi-AP coordination and performing multi-AP coordination with the second AP, wherein non-AP stations (STAs) belonging to the first BSS enable NPCA or disable NPCA during the multi-AP coordination with the second AP depending on the indication.

Description

SPECIFICATIONCONTROLLING NON-PRIMARY CHANNEL ACCESS (NPCA) DURING MULTIACCESS POINT COORDINATIONCROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of U.S. Provisional Application No. 63 / 723,007, filed November 20, 2024, titled “Triggering event of Non-primary channel access(NPCA) coexist with M-AP schemes”, which is hereby incorporated by reference.TECHNICAL FIELD

[0002] The present disclosure generally relates to wireless communications, and more specifically, relates to controlling non-primary channel access (NPCA) during multi-access point coordination.BACKGROUND

[0003] Institute of Electrical and Electronics Engineers (IEEE) 802.11 is a set of standards for implementing wireless local area network communication in various frequencies, including but not limited to the 2.4 gigahertz (GHz), 5 GHz, 6 GHz, and 60 GHz bands. These standards define the protocols that enable Wi-Fi devices to communicate with each other. The IEEE 802.11 family of standards has evolved over time to accommodate higher data rates, improved security, and better performance in different environments. Some of the most widely used standards include 802.11a, 802.11b, 802.11g, 802.1 In, 802.1 lac, and 802.1 lax (also known as “Wi-Fi 6”). These standards specify the modulation techniques, channel bandwidths, and other technical aspects that facilitate interoperability between devices from various manufacturers. IEEE 802.11 has played an important role in the widespread adoption of wireless networking in homes, offices, and public spaces, enabling users to connect their devices to the internet and each other without the need for wired connections.

[0004] IEEE 802.1 Ibe, also known as “Wi-Fi 7”, is the next generation of the IEEE 802.11 family of standards for wireless local area networks. Currently under development, 802.1 Ibe aims to significantly improve upon the capabilities of its predecessor, 802.1 lax / Wi-Fi 6, by offering even higher data rates, lower latency, and increased reliability. The standard is expected to leverage advanced technologies such as multi-link operation (MLO), which allows devices to simultaneously use multiple frequency bands and channels for enhanced performance andDocket No. 1002P24027W01 Client Matter No. P24-027WO1reliability. 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 these advancements, 802.1 Ibe is expected to deliver theoretical maximum data rates of up to 46 gigabits per second (Gbps), making it suitable for bandwidth-intensive applications such as virtual and augmented reality, 8K video streaming, and high-performance gaming.

[0005] According to traditional IEEE 802.11 wireless networking standards, before a wireless device can transmit a physical layer protocol data unit (PPDU), the wireless device has to verify that the transmission bandwidth, including the primary channel, is idle. For example, consider a station (STA) having an operating bandwidth (OPBW) of 80 MHz. The 80 MHz operating bandwidth may include a primary 20 MHz (P20) channel, a secondary 20 MHz (S20) channel, and a secondary 40 MHz (S40) channel. To transmit a 40 MHz PPDU, both the P20 and S20 channels within the 80 MHz operating bandwidth have to be idle. In a scenario where the P20 channel is busy but the S40 is idle, the STA is not allowed to transmit a 40 MHz PPDU in the S40 channel (even though it is idle) due to an existing rule that transmission is not allowed when the primary channel is busy.

[0006] In IEEE 802.1 Ibn (also referred to as ultra high reliability (or “UHR”)), with the increase in the operating bandwidth (e.g., to 320 MHz), the traditional rule that prevents PPDU transmission when the primary channel is busy and the secondary channel is idle (e.g., P20 channel is busy and secondary 160 MHz (SI 60) channel is idle) is seen as inefficient and wasteful of resources. The concept of non-primary channel access (NPCA) has been proposed to address this issue. With NPCA, transmission and reception can be performed in an idle nonprimary channel (e.g., a secondary channel) even if the primary channel is busy. That is, even if the primary channel is busy, if there is a non-primary channel that is idle, NPCA allows transmission / reception in the idle non-primary channel.

[0007] Coordinated time division multiple access (C-TDMA or c-TDMA) is a multi-AP coordination scheme that allows APs to share TXOPs with each other. For example, with C- TDMA, a first AP that owns a TXOP may share a portion of the TXOP with a second AP (stated differently, the first AP may allocate a portion of the TXOP to the second AP to allow the second AP to transmit and receive during the allocated portion). The second AP may then transmit and receive in its BSS during the allocated portion of the TXOP. If the second AP finishes transmission and reception before its allocated portion of the TXOP expires, the second AP may be allowed to return the TXOP to the first AP so that the first AP can resume theDocket No. 1002P24027W01Client Matter No. P24-027WO1TXOP. In this TXOP sharing scenario, the first AP may be referred to as the sharing AP and the second AP may be referred to as the shared AP.

[0008] The shared AP may begin its allocated portion of the sharing AP’s TXOP with a frame exchange in its BSS such as a multi-user request-to-send (MU-RTS) frame and clear-to-send (CTS) frame exchange. This frame exchange can trigger NPCA-capable AP / STAs of the sharing AP’s BSS to perform NPCA. As mentioned above, in a c-TDMA scenario, the shared AP may be allowed to return the TXOP to the sharing AP if the shared AP completes transmission and reception earlier than expected (before the shared AP’s allocated portion of the sharing AP’s TXOP expires). The shared AP may notify the sharing AP of the TXOP return by transmitting a TXOP return frame or equivalent frame to the sharing AP. However, if the sharing AP and shared AP have the same primary channel and the sharing AP’s BSS performs NPCA outside of the operating bandwidth of the shared AP, then the sharing AP may not be able to receive the TXOP return frame from the shared AP, resulting in the TXOP going unused, which is an inefficient usage of the TXOP.BRIEF DESCRIPTION OF THE DRAWINGS

[0009] 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.

[0010] 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.

[0011] Figure 2 is a schematic diagram of a wireless device, in accordance with some embodiments of the present disclosure.

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

[0013] Figure 3B illustrates components of a wireless device configured to receive data, in accordance with some embodiments of the present disclosure.

[0014] Figure 4 illustrates interframe space (IFS) relationships, in accordance with some embodiments of the present disclosure.

[0015] 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.Docket No. 1002P24027W01Client Matter No. P24-027WO1

[0016] 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.

[0017] 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.

[0018] 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.

[0019] 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.

[0020] Figure 10 is a diagram showing the overcall concept of non-primary channel access (NPCA), according to some embodiments.

[0021] Figure 11 is a diagram showing a coordinated time division multiple access (c-TDMA) scenario where transmission opportunity (TXOP) return is not allowed and the shared access point (AP) uses all of its allocated portion of the TXOP, according to some embodiments.

[0022] Figure 12 is a diagram showing a c-TDMA scenario where TXOP return is allowed and the sharing AP resumes the TXOP after receiving a TXOP return frame from the shared AP, according to some embodiments.

[0023] Figure 13 is a diagram showing a duration / ID field included in the multi-user request- to-send TXOP sharing (MU-RTS TXS) frame being set to the sum of a clear-to-send (CTS) frame transmission duration and one short interframe space (SIFS) interval duration, according to some embodiments.

[0024] Figure 14 is a diagram showing a c-TDMA scenario, according to some embodiments.

[0025] Figure 15 is a diagram showing an example of an operating bandwidth, primary channel, non-primary channel access (NPCA) primary channel, and NPCA available channel for a sharing AP and a shared AP, according to some embodiments.

[0026] Figure 16 is a diagram showing how NPCA operation in a c-TDMA scenario can prevent the sharing AP from being able to receive a TXOP return frame from the shared AP, according to some embodiments.

[0027] Figure 17 is a diagram showing a c-TDMA scenario where NPCA is indicated as being allowed, according to some embodiments.Docket No. 1002P24027W01Client Matter No. P24-027WO1

[0028] Figure 18 is a diagram showing a c-TDMA scenario where NPCA is indicated as not being allowed, according to some embodiments.

[0029] Figure 19 is a diagram showing a c-TDMA scenario where TXOP return is allowed, according to some embodiments.

[0030] Figure 20 is a diagram showing a c-TDMA scenario where TXOP return is not allowed, according to some embodiments.

[0031] Figure 21 is a flow diagram of a method for controlling NPCA during multi -AP coordination, according to some embodiments.

[0032] Figure 22 is a flow diagram of a method for enabling or disabling NPCA during multi- AP coordination, according to some embodiments.

[0033] Figure 23 is a flow diagram of a method for performing multi-AP coordination, according to some embodiments.

[0034] Figure 24 is a flow diagram of a method for disabling NPCA during multi-AP coordination, according to some embodiments.DETAILED DESCRIPTION

[0035] The present disclosure generally relates to wireless communications, and more specifically, relates to controlling non-primary channel access (NPCA) operating during multiaccess point coordination.

[0036] As mentioned above, in a coordinated time division multiple access (c-TDMA) scenario, transmission and reception in the shared access point’s (AP’s) basic service set (BSS) can trigger NPCA operation in the sharing AP’s BSS, which may prevent the sharing AP from being able to receive a transmission opportunity (TXOP) return frame from the shared AP, which may result in the inefficient usage of the TXOP.

[0037] The present disclosure introduces a technique to control NPCA operation during c- TDMA and other multi-AP coordination situations. According to some embodiments, a first AP (e.g., a sharing AP) may transmit an indication in its BSS of whether NPCA is allowed in the first AP’s BSS during multi-AP coordination. The non-AP STAs in the first AP’s BSS may enable NPCA or disable NPCA during multi-AP coordination between the first AP and a second AP depending on the indication. If the multi-AP coordination between the first AP and the second AP is c-TDMA, the indication (of whether NPCA is allowed) may be transmitted in a multi-user request-to-send transmission opportunity sharing frame (MU-RTS TXS) transmitted by the first AP to initiate the c-TDMA with the second AP. In an embodiment, the indication (of whether NPCA is allowed) is transmitted during a capabilities exchange in the first AP’sDocket No. 1002P24027W01Client Matter No. P24-027WO1BSS. If NPCA is allowed in the first AP’s BSS, the non-AP STAs of the first AP’s BSS may perform NPCA if they detect an overlapping basic service set (OBSS) transmission in the primary channel of the first AP’s BSS. However, if NPCA is not allowed in the first AP’s BSS, the non-AP STAs of the first AP’s BSS may refrain from performing NPCA in the first AP’s BSS during the multi -AP coordination between the first AP and the second AP even when an OBSS transmission occurs in the primary channel of the first AP’s BSS. In an embodiment, NPCA is not allowed by default during multi-AP coordination.

[0038] Being able to control / di sable NPCA operation during multi-AP coordination situations may allow the coordinating AP (e.g., the AP that initiates the multi-AP coordination) to receive communications from the coordinated AP (e.g., the AP that participates in the multi-AP coordination with the coordinating AP), when needed. For example, in a c-TDMA scenario, being able to control / disable NPCA operation in the sharing AP’s BSS may allow the sharing AP to receive a TXOP return frame from the shared AP, which allows the sharing AP to resume the TXOP, which allows for more efficient usage of the TXOP.

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

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

[0041] Figure 1 shows a wireless local area network (WLAN) 100 with a basic service set (BSS) 102 that includes a plurality of wireless devices 104 (sometimes referred to as WLAN devices 104). Each of the wireless devices 104 may include a medium access control (MAC) layer and a physical (PHY) layer according to an IEEE (Institute of Electrical and Electronics Engineers) standard 802.11, including one or more of the amendments(e.g., 802.1 la / b / g / n / p / ac / ax / bd / be). In one embodiment, the MAC layer of a wireless device 104 may initiate transmission of a frame to another wireless device 104 by passing a PHY- TXSTART. request (TXVECTOR) to the PHY layer. The TXVECTOR provides parameters for generating and / or transmitting a corresponding frame. Similarly, a PHY layer of a receivingDocket No. 1002P24027W01Client Matter No. P24-027WO1wireless device may generate an RXVECTOR, which includes parameters of a received frame and is passed to a MAC layer for processing.

[0042] The plurality of wireless devices 104 may include a wireless device 104A that is an access point (sometimes referred to as an AP station or AP STA) and the other wireless devices 104B1-104B4 that are non-AP stations (sometimes referred to as non-AP STAs). Alternatively, all the plurality of wireless devices 104 may be non-AP STAs in an ad-hoc networking environment. In general, the AP STA (e.g., wireless device 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).

[0043] Figure 2 illustrates a schematic block diagram of a wireless device 104, according to an embodiment. The wireless device 104 may be the wireless device 104A (i.e., the AP of the WLAN 100) or any of the wireless devices 104B1-104B4 in Figure 1. The wireless device 104 includes a baseband processor 210, a radio frequency (RF) transceiver 240, an antenna unit 250, a storage device (e.g., memory device) 232, one or more input interfaces 234, and one or more output interfaces 236. The baseband processor 210, the storage device 232, the input interfaces 234, the output interfaces 236, and the RF transceiver 240 may communicate with each other via a bus 260.

[0044] The baseband processor 210 performs baseband signal processing and includes a MAC processor 212 and a PHY processor 222. The baseband processor 210 may utilize the memory 232, which may include a non-transitory computer / machine readable medium having software (e.g., computer / machine programing instructions) and data stored therein.

[0045] In an embodiment, the MAC processor 212 includes a MAC software processing unit 214 and a MAC hardware processing unit 216. The MAC software processing unit 214 may implement a first plurality of functions of the MAC layer by executing MAC software, which may be included in the software stored in the storage device 232. The MAC hardware processing unit 216 may implement a second plurality of functions of the MAC layer in specialpurpose hardware. However, the MAC processor 212 is not limited thereto. For example, the MAC processor 212 may be configured to perform the first and second plurality of functions entirely in software or entirely in hardware according to an implementation.

[0046] The PHY processor 222 includes a transmitting (TX) signal processing unit (SPU) 224 and a receiving (RX) SPU 226. The PHY processor 222 implements a plurality of functions ofDocket No. 1002P24027W01Client Matter No. P24-027WO1the PHY layer. These functions may be performed in software, hardware, or a combination thereof according to an implementation.

[0047] Functions performed by the transmitting SPU 224 may include one or more of Forward Error Correction (FEC) encoding, stream parsing into one or more spatial streams, diversity encoding of the spatial streams into a plurality of space-time streams, spatial mapping of the space-time streams to transmit chains, inverse Fourier Transform (iFT) computation, Cyclic Prefix (CP) insertion to create a Guard Interval (GI), and the like. Functions performed by the receiving SPU 226 may include inverses of the functions performed by the transmitting SPU 224, such as GI removal, Fourier Transform computation, and the like.

[0048] The RF transceiver 240 includes an RF transmitter 242 and an RF receiver 244. The RF transceiver 240 is configured to transmit first information received from the baseband processor 210 to the WLAN 100 (e.g., to another WLAN device 104 of the WLAN 100) 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.

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

[0050] The input interfaces 234 receive information from a user, and the output interfaces 236 output information to the user. The input interfaces 234 may include one or more of a keyboard, keypad, mouse, touchscreen, microphone, and the like. The output interfaces 236 may include one or more of a display device, touch screen, speaker, and the like.

[0051] As described herein, many functions of the WLAN device 104 may be implemented in either hardware or software. Which functions are implemented in software and which functions are implemented in hardware will vary according to constraints imposed on a design. The constraints may include one or more of design cost, manufacturing cost, time to market, power consumption, available semiconductor technology, etc.

[0052] As described herein, a wide variety of electronic devices, circuits, firmware, software, and combinations thereof may be used to implement the functions of the components of the WLAN device 104. Furthermore, the WLAN device 104 may include other components, such as application processors, storage interfaces, clock generator circuits, power supply circuits, and the like, which have been omitted in the interest of brevity.Docket No. 1002P24027W01Client Matter No. P24-027WO1

[0053] Figure 3 A illustrates components of a WLAN device 104 configured to transmit data according to an embodiment, including a transmitting (Tx) SPU (TxSP) 324, an RF transmitter 342, and an antenna 352. In an embodiment, the TxSP 324, the RF transmitter 342, and the antenna 352 correspond to the transmitting SPU 224, the RF transmitter 242, and an antenna of the antenna unit 250 of Figure 2, respectively.

[0054] The TxSP 324 includes an encoder 300, an interleaver 302, a mapper 304, an inverse Fourier transformer (TFT) 306, and a guard interval (GI) inserter 308.

[0055] The encoder 300 receives and encodes input data. In an embodiment, the encoder 300 includes a forward error correction (FEC) encoder. The FEC encoder may include a binary convolution code (BCC) encoder followed by a puncturing device. The FEC encoder may include a low-density parity-check (LDPC) encoder.

[0056] The TxSP 324 may further include a scrambler for scrambling the input data before the encoding is performed by the encoder 300 to reduce the probability of long sequences of 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.

[0057] The interleaver 302 interleaves the bits of each stream output from the encoder 300 to change an order of bits therein. The interleaver 302 may apply the interleaving only when the encoder 300 performs BCC encoding and otherwise may output the stream output from the encoder 300 without changing the order of the bits therein.

[0058] The mapper 304 maps the sequence of bits output from the interleaver 302 to constellation points. If the encoder 300 performed LDPC encoding, the mapper 304 may also perform LDPC tone mapping in addition to constellation mapping.

[0059] When the TxSP 324 performs a MIMO or MU-MIMO transmission, the TxSP 324 may include a plurality of interleavers 302 and a plurality of mappers 304 according to a number of spatial streams (NSS) of the transmission. The TxSP 324 may further include a stream parser for dividing the output of the encoder 300 into blocks and may respectively send the blocks to different interleavers 302 or mappers 304. The TxSP 324 may further include a space-time block code (STBC) encoder for spreading the constellation points from the spatial streams into a number of space-time streams (NSTS) and a spatial mapper for mapping the space-time streams to transmit chains. The spatial mapper may use direct mapping, spatial expansion, or beamforming.

[0060] The IFT 306 converts a block of the constellation points output from the mapper 304 (or, when MIMO or MU-MIMO is performed, the spatial mapper) to a time domain block (i.e., aDocket No. 1002P24027W01Client Matter No. P24-027WO1symbol) by using an inverse discrete Fourier transform (IDFT) or an inverse fast Fourier transform (IFFT). If the STBC encoder and the spatial mapper are used, the IFT 306 may be provided for each transmit chain.

[0061] When the TxSP 324 performs a MIMO or MU-MIMO transmission, the TxSP 324 may insert cyclic shift diversities (CSDs) to prevent unintentional beamforming. The TxSP 324 may perform the insertion of the CSD before or after the IFT 306. The CSD may be specified per transmit chain or may be specified per space-time stream. Alternatively, the CSD may be applied as a part of the spatial mapper.

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

[0063] The GI inserter 308 prepends a GI to each symbol produced by the IFT 306. Each GI may include a Cyclic Prefix (CP) corresponding to a repeated portion of the end of the symbol that the GI precedes. The TxSP 324 may optionally perform windowing to smooth edges of each symbol after inserting the GI.

[0064] The RF transmitter 342 converts the symbols into an RF signal and transmits the RF signal via the antenna 352. When the TxSP 324 performs a MIMO or MU-MIMO transmission, the GI inserter 308 and the RF transmitter 342 may be provided for each transmit chain.

[0065] Figure 3B illustrates components of a WLAN device 104 configured to receive data according to an embodiment, including a Receiver (Rx) SPU (RxSP) 326, an RF receiver 344, and an antenna 354. In an embodiment, the RxSP 326, RF receiver 344, and antenna 354 may correspond to the receiving SPU 226, the RF receiver 244, and an antenna of the antenna unit 250 of Figure 2, respectively.

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

[0067] The RF receiver 344 receives an RF signal via the antenna 354 and converts the RF signal into symbols. The GI remover 318 removes the GI from each of the symbols. When the received transmission is a MIMO or MU-MIMO transmission, the RF receiver 344 and the GI remover 318 may be provided for each receive chain.

[0068] The FT 316 converts each symbol (that is, each time domain block) into a frequency domain block of constellation points by using a discrete Fourier transform (DFT) or a fast Fourier transform (FFT). The FT 316 may be provided for each receive chain.

[0069] When the received transmission is the MIMO or MU-MIMO transmission, the RxSP 326 may include a spatial demapper for converting the respective outputs of the FTs 316 of the receiver chains to constellation points of a plurality of space-time streams, and an STBCDocket No. 1002P24027W01Client Matter No. P24-027WO1decoder for despreading the constellation points from the space-time streams into one or more spatial streams.

[0070] The demapper 314 demaps the constellation points output from the FT 316 or the STBC decoder to bit streams. If the received transmission was encoded using LDPC encoding, the demapper 314 may further perform LDPC tone demapping before performing the constellation demapping.

[0071] The deinterleaver 312 deinterleaves the bits of each stream output from the demapper 314. The deinterleaver 312 may perform the deinterleaving only when the received transmission was encoded using BCC encoding, and otherwise may output the stream output by the demapper 314 without performing deinterleaving.

[0072] When the received transmission is the MIMO or MU-MIMO transmission, theRxSP 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.

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

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

[0075] Before making a transmission, wireless devices such as wireless device 104 will assess the availability of the wireless medium using Clear Channel Assessment (CCA). If the medium is occupied, CCA may determine that it is busy, while if the medium is available, CCA determines that it is idle.

[0076] The PHY entity for IEEE 802.11 is based on Orthogonal Frequency Division Multiplexing (OFDM) or Orthogonal Frequency Division Multiple Access (OFDMA). In either OFDM or OFDMA Physical (PHY) layers, a STA (e.g., a wireless device 104) is capable of transmitting and receiving Physical Layer (PHY) Protocol Data Units (PPDUs) (also referred to as PLCP (Physical Layer Convergence Procedure) Protocol Data Units) that are compliant with the mandatory PHY specifications. A PHY specification defines a set of Modulation and Coding Schemes (MCS) and a maximum number of spatial streams. Some PHY entities define downlink (DL) and uplink (UL) Multi-User (MU) transmissions having a maximum number ofDocket No. 1002P24027W01Client Matter No. P24-027WO1space-time streams (STS) per user and employing up to a predetermined total number of STSs. A PHY entity may provide support for 10 Megahertz (MHz), 20 MHz, 40 MHz, 80 MHz, 160 MHz, 240 MHz, and 320 MHz contiguous channel widths and support for an 80+80, 80+160 MHz, and 160+160 MHz non-contiguous channel width. Each channel includes a plurality of subcarriers, which may also be referred to as tones. A PHY entity may define signaling fields denoted as Legacy Signal (L-SIG), Signal A (SIG-A), and Signal B (SIG-B), and the like within a PPDU by which some necessary information about PHY Service Data Unit (PSDU) attributes are communicated. The descriptions below, for sake of completeness and brevity, refer to OFDM-based 802.11 technology. Unless otherwise indicated, a station refers to a non-AP STA.

[0077] Figure 4 illustrates Inter-Frame Space (IFS) relationships. In particular, Figure 4 illustrates a Short IFS (SIFS), a Point Coordination Function (PCF) IFS (PIFS), a Distributed Coordination Function (DCF) IFS (DIFS), and an Arbitration IFSs corresponding to an 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.

[0078] A management frame may be used for exchanging management information, which is not forwarded to the higher layer. Subtype frames of the management frame include a beacon frame, an association request / response frame, a probe request / response frame, and an authentication request / response frame.

[0079] A control frame may be used for controlling access to the medium. Subtype frames of the control frame include a request to send (RTS) frame, a clear to send (CTS) frame, and an acknowledgement (ACK) frame.

[0080] When the control frame is not a response frame of another frame, the WLAN device 104 transmits the control frame after performing backoff if a DIFS has elapsed during which the medium has been idle. When the control frame is the response frame of another frame, the WLAN device 104 transmits the control frame after a SIFS has elapsed without performing backoff or checking whether the medium is idle.

[0081] A WLAN device 104 that supports Quality of Service (QoS) functionality (that is, a QoS STA) may transmit the frame after performing backoff if an AIFS for an associated access category (AC) (i.e., AIFS[AC]) has elapsed. When transmitted by the QoS STA, any of the data frame, the management frame, and the control frame, which is not the response frame, may use the AIFS[AC] of the AC of the transmitted frame.Docket No. 1002P24027W01Client Matter No. P24-027WO1

[0082] A WLAN device 104 may perform a backoff procedure when the WLAN device 104 that is ready to transfer a frame finds the medium busy. The backoff procedure includes determining a random backoff time composed of N backoff slots, where each backoff slot has a duration equal to a slot time and N being an integer number greater than or equal to zero. The backoff time may be determined according to a length of a Contention Window (CW). In an embodiment, the backoff time may be determined according to an AC of the frame. All backoff slots occur following a DIFS or Extended IFS (EIFS) period during which the medium is determined to be idle for the duration of the period.

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

[0084] The backoff procedure operates so that when multiple WLAN devices 104 are deferring and execute the backoff procedure, each WLAN device 104 may select a backoff time using a random function and the WLAN device 104 that selects the smallest backoff time may win the contention, reducing the probability of a collision.

[0085] Figure 5 illustrates a Carrier Sense Multiple Access / Collision Avoidance (CSMA / CA) based frame transmission procedure for avoiding collision between frames in a channel according to an embodiment. Figure 5 shows a first station STA1 transmitting data, a second station STA2 receiving the data, and a third station STA3 that may be located in an area where a frame transmitted from the STA1 can be received, a frame transmitted from the second station STA2 can be received, or both can be received. The stations STA1, STA2, and STA3 may be WLAN devices 104 of Figure 1.

[0086] The station STA1 may determine whether the channel is busy by carrier sensing. The station STA1 may determine channel occupation / status based on an energy level in the channel or an autocorrelation of signals in the channel, or may determine the channel occupation by using a network allocation vector (NAV) timer.

[0087] After determining that the channel is not used by other devices (that is, that the channel is IDLE) during a DIFS (and performing backoff if required), the station STA1 may transmit a Request-To-Send (RTS) frame to the station STA2. Upon receiving the RTS frame, after a SIFS the station STA2 may transmit a Clear-To-Send (CTS) frame as a response to the RTS frame. If Dual-CTS is enabled and the station STA2 is an AP, the AP may send two CTS frames inDocket No. 1002P24027W01Client Matter No. P24-027WO1response to the RTS frame (e.g., a first CTS frame in a non-High Throughput format and a second CTS frame in the HT format).

[0088] When the station STA3 receives the RTS frame, it may set a NAV timer of the station STA3 for a transmission duration of subsequently transmitted frames (for example, a duration of SIFS + CTS frame duration + SIFS + data frame duration + SIFS + ACK frame duration) using duration information included in the RTS frame. When the station STA3 receives the CTS frame, it may set the NAV timer of the station STA3 for a transmission duration of subsequently transmitted frames using duration information included in the CTS frame. Upon receiving a new frame before the NAV timer expires, the station STA3 may update the NAV timer of the station STA3 by using duration information included in the new frame. The station STA3 does not attempt to access the channel until the NAV timer expires.

[0089] When the station STA1 receives the CTS frame from the station STA2, it may transmit a data frame to the station STA2 after a SIFS period elapses from a time when the CTS frame has been completely received. Upon successfully receiving the data frame, the station STA2 may transmit an ACK frame as a response to the data frame after a SIFS period elapses.

[0090] When the NAV timer expires, the third station STA3 may determine whether the channel is busy using the carrier sensing. Upon determining that the channel is not used by other devices during a DIFS period after the NAV timer has expired, the station STA3 may attempt to access the channel after a contention window elapses according to a backoff process.

[0091] When Dual-CTS is enabled, a station that has obtained a transmission opportunity (TXOP) and that has no data to transmit may transmit a CF-End frame to cut short the TXOP. An AP receiving a CF-End frame having a Basic Service Set Identifier (BSSID) of the AP as a destination address may respond by transmitting two more CF-End frames: a first CF-End frame using Space Time Block Coding (STBC) and a second CF-End frame using non-STBC. A station receiving a CF-End frame resets its NAV timer to 0 at the end of the PPDU containing the CF-End frame. Figure 5 shows the station STA2 transmitting an ACK frame to acknowledge the successful reception of a frame by the recipient.

[0092] The IEEE 802.1 Ibn (Ultra High Reliability, UHR) working group has been established to address the growing demand for higher peak throughput and reliability in Wi-Fi. As shown in Figure 6, the peak PHY rate has significantly increased from IEEE 802.1 lb to IEEE 802.1 Ibe (Wi-Fi 7), with the latter focusing on further improving peak throughput. The UHR study group aims to enhance the tail of the latency distribution and jitter to support applications that require low latency, such as video-over- WLAN, gaming, AR, and VR. It is noted that variousDocket No. 1002P24027W01Client Matter No. P24-027WO1characteristics of UHR (e.g., max PHY rate, PHY rate enhancement, bandwidth / number of spatial streams, and operating bands) are still to be determined.

[0093] The focus of IEEE 802.1 Ibe is primarily on WLAN indoor and outdoor operation with stationary and pedestrian speeds in the 2.4, 5, and 6 GHz frequency bands. In addition to peak PHY rate, different candidate features are under discussion. These candidate features include (1) a 320MHz bandwidth and a more efficient utilization of a non-contiguous spectrum, (2) multi -band / multi -channel aggregation and operation, (3) 16 spatial streams and Multiple Input Multiple Output (MIMO) protocol enhancements, (4) multi-Access Point (AP) Coordination (e.g., coordinated and joint transmission), (5) an enhanced link adaptation and retransmission protocol (e.g., Hybrid Automatic Repeat Request (HARQ)), and (6) adaptation to regulatory rules specific to a 6 GHz spectrum.

[0094] The focus of IEEE 802.1 Ibn (UHR) is still under discussion, with candidate features including MLO enhancements (e.g., in terms of increased throughput / reliability and decreased latency), latency and reliability improvements (e.g., multi-AP coordination to support low latency traffic), bandwidth expansion (e.g., to 240, 480, 640 MHz), aggregated PPDU (A- PPDU), enhanced multi-link single-radio (eMLSR) extensions to AP, roaming improvements, and power-saving schemes for prolonging battery life.

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

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

[0097] In the process of wireless communication, a transmitting station (STA) creates a Physical Layer Protocol Data Unit (PPDU) frame and sends it to a receiving STA. The receiving STA then receives, detects, and processes the PPDU.

[0098] The Extremely High Throughput (EHT) PPDU frame encompasses several components. It includes a legacy part, which comprises fields such as the Legacy Short Training Field (L-STF), Legacy Long Training Field (L-LTF), Legacy Signal Field (L-SIG), andDocket No. 1002P24027W01Client Matter No. P24-027WO1Repeated Legacy Signal Field (RL-SIG). These fields are used to maintain compatibility with older Wi-Fi standards.

[0099] In addition to the legacy part, the EHT PPDU frame also contains the Universal Signal Field (U-SIG), EHT Signal Field (EHT-SIG), EHT Short Training Field (EHT-STF), and EHT Long Training Field (EHT-LTF). These fields are specific to the EHT standard and are used for various purposes, such as signaling, synchronization, and channel estimation.

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

[0101] Regarding the Ultra High Reliability (UHR) PPDU, its frame structure is currently undefined and will be determined through further discussions within the relevant working group or study group. This indicates that the specifics of the UHR PPDU are still under development and will be finalized based on the outcomes of future deliberations.

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

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

[0104] For the purpose of this disclosure, MU transmission refers to situations where multiple frames are transmitted to or from multiple STAs simultaneously using different resources. Examples of these resources include different frequency resources in Orthogonal Frequency Division Multiple Access (OFDMA) transmission and different spatial streams in Multi-User Multiple Input Multiple Output (MU-MIMO) transmission. Consequently, downlink OFDMA (DL-OFDMA), downlink MU-MIMO (DL-MU-MIMO), uplink OFDMA (UL- OFDMA), uplink MU-MIMO (UL-MU-MIMO), and OFDMA with MU-MIMO are all considered examples of MU transmission.Docket No. 1002P24027W01Client Matter No. P24-027WO1

[0105] Figure 8 illustrates an example of multi-user (MU) transmission in Orthogonal Frequency-Division Multiple Access (OFDMA), in accordance with some embodiments of the present disclosure.

[0106] In the IEEE 802.1 lax and 802.1 Ibe specifications, the trigger frame plays a useful role in facilitating uplink multi-user (MU) transmissions. The purpose of the trigger frame is to allocate resources and solicit one or more Trigger-based (TB) Physical Layer Protocol Data Unit (PPDU) transmissions from the associated stations (STAs).

[0107] The trigger frame contains information required by the responding STAs to send their Uplink TB PPDUs. This information includes the Trigger type, which specifies the type of TB PPDU expected, and the Uplink Length (UL Length), which indicates the duration of the uplink transmission.

[0108] Figure 9 illustrates an example scenario where an access point (AP) operating in an 80MHz bandwidth environment sends a Trigger frame to multiple associated STAs. 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.

[0109] After successfully receiving the UL OFDMA TB PPDUs, the AP acknowledges the STAs by sending an acknowledgement frame. This acknowledgement can be in the form of an 80MHz width multi-STA Block Acknowledgement (Block Ack) or a Block Acknowledgement with a Direct Feedback (DF) OFDMA method. The multi-STA Block Ack allows the AP to acknowledge multiple STAs simultaneously, while the Block Ack with DF OFDMA enables the AP to provide feedback to the STAs using the same OFDMA technique employed in the uplink transmission.

[0110] The trigger frame is a useful component in enabling efficient uplink MU transmissions in IEEE 802.1 lax and 802.1 Ibe networks, by allocating resources and coordinating the uplink transmissions from multiple STAs within the same bandwidth.

[0111] Wireless network systems can rely on retransmission of media access control (MAC) protocol data units (MPDUs) when the transmitter (TX) does not receive an acknowledgement from the receiver (RX) or MPDUs are not successfully decoded by the receiver. Using an automatic repeat request (ARQ) approach, the receiver discards the last failed MPDU before receiving the newly retransmitted MPDU. With requirements of enhanced reliability and reduced latency, the wireless network system can evolve toward a hybrid ARQ (HARQ) approach.Docket No. 1002P24027W01Client Matter No. P24-027WO1

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

[0113] Since the receiver uses both the current and the previously received subpackets for decoding data, the error probability in decoding decreases as the number of used 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.

[0114] In a second type of HARQ scheme, also referred to as an incremental redundancy (IR) HARQ (IR-HARQ) scheme, different puncturing patterns are used for each subpacket such that the signal changes for each retransmitted subpacket in comparison to the originally transmitted subpacket. IR-HARQ alternatively uses two puncturing patterns for odd numbered and even numbered transmissions, respectively. The redundancy scheme of IR-HARQ improves the log likelihood ratio (LLR) of parity bit(s) in order to combine information sent across different transmissions due to requests and lowers the code rate as the additional subpacket is used. This results in a lower error rate of the subpacket in comparison to CC-HARQ. The puncturing pattern used in IR-HARQ is indicated by a subpacket identity (SPID) indication. The SPID of the first subpacket may always be set to 0 and all the systematic bits and the punctured parity bits are transmitted in the first subpacket. Self-decoding is possible when the receiving signal- to-noise ratio (SNR) environment is good (i.e., a high SNR). In some embodiments, subpacketsDocket No. 1002P24027W01Client Matter No. P24-027WO1with corresponding SPIDs to be transmitted are in increasing order of SPID but can be exchanged / switched except for the first SPID.

[0115] AP coordination has been considered as a potential technology to improve WLAN system throughput in the IEEE 802.1 Ibe standard and is still being discussed in the IEEE 802.1 Ibn (UHR) standard. To support various AP coordination schemes, such as coordinated beamforming, OFDMA, TDMA, spatial reuse, and joint transmission, a predefined mechanism for APs is necessary.

[0116] In the context of coordinated TDMA (c-TDMA), the AP that obtains a transmit opportunity (TXOP) is referred to as the sharing AP. This AP initiates the AP coordination schemes to determine the AP candidate set by sending a frame, such as a Beacon frame or probe response frame, which includes information about the AP coordination scheme capabilities. The AP that participates in the AP coordination schemes after receiving the frame from the sharing AP is called the shared AP. The sharing AP is also known as the master AP or coordinating AP, while the shared AP is referred to as the slave AP or coordinated AP.

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

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

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

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

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

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

[0123] Figure 10 is a diagram showing the overcall concept of NPCA, according to some embodiments.

[0124] The diagram shows the overall concept of NPCA when the operating bandwidth is 80 MHz. It should be appreciated, however, that NPCA is not limited to being used with an 80 MHz operating bandwidth but can be used with other operating bandwidth sizes. The 80 MHz operating bandwidth may include a primary 20 MHz (P20) channel, a secondary 20 MHz (P20) channel, and a secondary 40 MHz (S40) channel. As shown in the diagram, when a 20 MHzDocket No. 1002P24027W01Client Matter No. P24-027WO1PPDU is transmitted in the P20 channel, the S20 channel and the S40 channel may be available. Also, when a 40 MHz PPDU is transmitted in the P40 channel, the S40 channel may be available. Traditional IEEE 802.11 wireless networks have a rule that does not allow transmission in non-primary channels (e.g., secondary channels) when the primary channel (e.g., the P20 channel) is busy even if the non-primary channels are idle.

[0125] In IEEE 802.1 Ibn (also referred to as ultra high reliability (or “UHR”)), with the increase in the operating bandwidth (e.g., to 320 MHz), the traditional rule that prevents PPDU transmission when the primary channel is busy and the secondary channel is idle (e.g., P20 channel is busy and secondary 160 MHz (SI 60) channel is idle) is seen as inefficient and wasteful of resources. The concept of non-primary channel access (NPCA) has been proposed to address this issue. With NPCA, transmission and reception can be performed in an idle non- primary channel (e.g., a secondary channel) even if the primary channel is busy. That is, even if the primary channel is busy, if there is a non-primary channel that is idle, NPCA allows transmission / reception in the idle non-primary channel.

[0126] With NPCA, even if the primary channel is busy due to OBSS signals, transmission and reception may be allowed in a non-primary channel if certain conditions are met (e.g., clear channel assessment (CCA) indicates that the non-primary channel is idle). For example, as shown in the diagram, a 60 MHz PPDU may be transmitted in the S20 channel and S40 channel while a 20 MHz OBSS PPDU is transmitted in the P20 channel. As another example, a 40 MHz PPDU may be transmitted in the S40 channel while an 40 MHz OBSS PPDU is transmitted in the P20 channel and the S20 channel. By making use of otherwise unused non-primary channels, NPCA may improve channel utilization and thus improve the overall throughput in the wireless network.

[0127] As used herein, NPCA AP / STAs or NPCA-capable AP / STAs may refer to AP / STAs that are capable of performing NPCA.

[0128] As used herein, NPCA available channel may refer to a channel that can be used for NPCA operation.

[0129] As used herein, NPCA primary channel may refer to a subchannel (e.g., a 20 MHz (sub)channel) of the NPCA available channel that is used for performing backoff for NPCA operation. The NPCA primary channel may perform a similar role to the primary channel that APs / STAs use during normal (non-NPCA) operation.

[0130] As used herein, MyBSS primary channel may refer to the primary channel of MyBSS.

[0131] As used herein, NPCA channel switching may refer to the act of switching from the MyBSS primary channel to the NPCA primary channel for NPCA operation.Docket No. 1002P24027W01Client Matter No. P24-027WO1

[0132] As used herein, NPCA duration may refer to the duration during which NPCA can be performed.

[0133] Coordinated time division multiple access (c-TDMA) is a multi-AP coordination scheme that allows APs to share TXOPs with each other. For example, with c-TDMA, a first AP that owns a TXOP may share a portion of the TXOP with a second AP (the first AP may allocate a portion of the TXOP to the second AP for the second AP to use). The second AP may then transmit and receive in its BSS during its allocated portion of the TXOP. In such a TXOP sharing scenario, the first AP may be referred to as the sharing AP and the second AP may be referred to as the shared AP. The sharing AP may also be referred to as the coordinating AP because it is the AP that initiates multi-AP coordination with the shared AP. The shared AP may also be referred to as the coordinated AP.

[0134] The sharing AP may indicate to the shared AP in advance whether the shared AP is allowed to return the TXOP. The shared AP may decide to return the TXOP if the shared AP will not use all of its allocated portion of the TXOP (e.g., if the shared AP finishes transmission and / or reception early before its allocated portion of the TXOP expires). The sharing AP may indicate to the shared AP whether TXOP return is allowed. If the sharing AP indicates that TXOP return is allowed, the shared AP may return the TXOP to the sharing AP before the shared AP’s allocated portion of the TXOP expires. If TXOP return is not allowed, the shared AP may use its allocated portion of the TXOP until it expires or provide a fair contention-based state (i.e., contention-free) that allows other STAs to access the channel for transmission.

[0135] Figure 11 is a diagram showing a c-TDMA scenario where TXOP return is not allowed and the shared AP uses all of its allocated portion of the TXOP, according to some embodiments.

[0136] As shown in the diagram, the sharing AP may transmit control frame 1105 to the shared AP to indicate to the shared AP that the sharing AP is allocating a portion of the sharing AP’s TXOP to the shared AP. In an embodiment, control frame 1105 is a MU-RTS TXS frame (which may be a type of trigger frame). Responsive to receiving control frame 1105, the shared AP may transmit response frame 1110 to the sharing AP. In an embodiment, response frame 1110 is a CTS frame. During the portion of the sharing AP’s TXOP allocated to the shared AP (depicted as “Time shared by sharing AP” in the diagram), the shared AP may transmit data frame 1115 to a STA that is associated with the shared AP. If the STA successfully receives data frame 1115, the STA may transmit BA frame 1120 to the shared AP. The sharing AP may resume its TXOP (e.g., resume transmission and reception with its associated non-AP STAs) after the portion of the TXOP allocated to the shared AP expires.Docket No. 1002P24027W01Client Matter No. P24-027WO1

[0137] Figure 12 is a diagram showing a c-TDMA scenario where TXOP return is allowed and the sharing AP resumes the TXOP after receiving a TXOP return frame from the shared AP, according to some embodiments.

[0138] The diagram illustrates a c-TDMA scenario where the sharing AP allocates a portion of its TXOP to the shared AP and allows TXOP return. The shared AP completes its transmission and reception before the allocated portion of the TXOP expires and the shared AP returns the TXOP to the sharing AP, which allows the sharing AP to resume the TXOP and continue transmission and reception with its associated non-AP STAs.

[0139] As shown in the diagram, the sharing AP may transmit control frame 1205 (e.g., MU- RTS TXS frame) to the shared AP to indicate to the shared AP that the sharing AP is allocating a portion of the sharing AP’s TXOP to the shared AP. Responsive to receiving control frame 1205, the shared AP may transmit response frame 1210 (e.g., CTS frame) to the sharing AP. During the portion of the sharing AP’s TXOP allocated to the shared AP (depicted as “Time shared by sharing AP” in the diagram), the shared AP may transmit data frame 1215 to an associated STA. If the STA successfully receives data frame 1215, the STA may transmit BA frame 1220 to the shared AP. If the shared AP finishes transmission reception in its BSS before the allocated portion of the TXOP expires, the shared AP may transmit TXOP return frame 1225 to the sharing AP to return the TXOP to the sharing AP. Upon receiving TXOP return frame 1225, the sharing AP may resume the TXOP. For example, the sharing AP may perform frame exchange 1230 in its BSS.

[0140] Figure 13 is a diagram showing a duration / ID field included in the MU-RTS TXS frame being set to the sum of a CTS frame transmission duration and one SIFS interval duration, according to some embodiments.

[0141] The diagram illustrates the NAV duration in a c-TDMA scenario where the sharing AP allocates a portion of its TXOP to the shared AP using control frames (e.g., MU-RTS TXS frame) and response frames (e.g., CTS frame).

[0142] As shown in the diagram, the sharing AP may transmit control frame 1305 (e.g., MU- RTS TXS frame) to the shared AP to indicate to the shared AP that the sharing AP is allocating a portion of the sharing AP’s TXOP to the shared AP. Responsive to receiving control frame 1305, the shared AP may transmit response frame 1310 (e.g., CTS frame) to the sharing AP after a SIFS interval after receiving control frame 1305. During the portion of the sharing AP’s TXOP allocated to the shared AP (depicted as “Time shared by sharing AP” in the diagram), the shared AP may transmit data frame 1315 to a STA that is associated with theDocket No. 1002P24027W01Client Matter No. P24-027WO1shared AP. If the STA successfully receives data frame 1315, the STA may transmit BA frame 1320 to the shared AP.

[0143] Control frame 1305 may set a NAV duration 1330 that corresponds to the sum of the duration of a SIFS interval and the transmission duration of response frame 1310. For example, if control frame 1305 is a MU-RTS TXS frame and response frame 1310 is a CTS frame, the duration / ID field included in the MU-RTS TXS frame may be set to indicate the duration required to transmit the CTS frame plus the duration of one SIFS interval.

[0144] As mentioned above, NPCA is a technology that allows transmission and reception in an available non-primary (secondary) channel when OBSS transmission occupies the primary channel. c-TDMA is a multi-AP coordination scheme where a sharing AP can share a portion of its TXOP with a shared AP so that the shared AP can transmit and receive during the sharing AP’s TXOP. Several issues may arise in a wireless network environment where c-TDMA and NPCA coexist. For example, as will be described in additional detail herein, issues may arise when the sharing AP’s BSS includes NPCA-capable AP / STAs.

[0145] Figure 14 is a diagram showing a c-TDMA scenario, according to some embodiments.

[0146] As shown in the diagram, a wireless network environment may include a sharing AP 1450 and STAs associated with the sharing AP such as STA2-1 and STA2-2. Also, the wireless network environment may include a shared AP 1460 and STAs associated with the shared AP such as STA1-1 and STA1-2. The wireless network environment may also include an OBSS STA that is not associated with either the sharing AP or the shared AP.

[0147] As shown in the diagram, the sharing AP 1450 may transmit control frame 1405 to the shared AP to share a portion of the sharing AP’s TXOP with the shared AP 1460. The shared AP 1460 may transmit response frame 1410 to the sharing AP after a SIFS interval after receiving control frame 1405. In an embodiment, control frame 1405 is a MU-RTS TXS frame and response frame 1410 is a CTS frame. Control frame 1405 may cause a NAV to be set for a NAV duration 1430 that corresponds to the transmission duration of response frame 1410 plus a SIFS interval duration (e.g., SIFS + duration of CTS frame). For example, the duration / ID field included in control frame 1405 may include a value indicating the duration of response frame 1410 plus a SIFS interval duration. After transmitting response frame 1410, the shared AP 1460 may perform frame exchange 1415 in the shared AP’s BSS during the portion of the sharing AP’s TXOP allocated to the shared AP 1460 (depicted in the diagram as “Time shared by sharing AP”).

[0148] Frame exchange 1415 may begin with an exchange of an initial control frame and an initial control response frame. For example, frame exchange 1415 may begin with an exchangeDocket No. 1002P24027W01Client Matter No. P24-027WO1of a (MU-)RTS frame and a CTS frame to minimize interference from OBSS APs / STAs. As another example, frame exchange 1415 may begin with an exchange of a buffer status report poll (BSRP) frame and a buffer status report (BSR) frame. Following the initial frame exchange, the shared AP 1460 may begin using its allocated portion of the TXOP to transmit and receive frames with its associated STAs (e.g., STA1-1 and STA1-2). The shared AP 1460 may determine which non-AP STA(s) should be prioritized for transmission and reception and perform frame exchanges with those non-AP STA(s) to more effectively utilize its allocated portion of the TXOP.

[0149] NPCA operation can be triggered in the sharing AP’s BSS if an OBSS PPDU (e.g., having a HT / VHT / HE / EHT / UHR PPDU format) occupies the primary channel of the sharing AP’s BSS. For example, frame exchange 1415 in the shared AP’s BSS (e.g., (MU-)RTS / CTS frame exchange, BSRP / BSR frame exchange, or other control frame exchange) or transmission by the OBSS STA can potentially trigger NPCA operation in the sharing AP’s BSS. If an OBSS transmission triggers NPCA operation of NPCA-capable AP / STAs of the sharing AP’s BSS during c-TDMA, the following issue may arise. If the shared AP completes its transmission and reception earlier than expected due to better channel conditions than anticipated (the channel condition during transmission / reception was better than the channel condition at the time the sharing AP shared the TXOP with the shared AP (e.g., at the time of the (MU)-RTS TXS frame and CTS frame exchange), the shared AP may transmit a TXOP return frame to the sharing AP to return the TXOP back to the sharing AP. However, if the sharing AP has switched channels to perform NPCA, the sharing AP may not be able to receive the TXOP return frame from the shared AP.

[0150] For example, assuming the channelization and topology of the sharing AP and shared AP are as shown in Figures 15 and 16, the NPCA-capable AP / STAs of the sharing AP’s BSS operating in the NPCA available channel will not be able to detect the TXOP return from the shared AP.

[0151] Figure 15 is a diagram showing an example of an operating bandwidth, primary channel, NPCA primary channel, and NPCA available channel for a sharing AP and a shared AP, according to some embodiments.

[0152] As shown in the diagram, the sharing AP may have an operating bandwidth of 160 MHz and the shared AP may have an operating bandwidth of 80 MHz. The primary channel of the sharing AP and the shared AP may be the lowest frequency 20 MHz channel. The NPCA available channel of the sharing AP may be the upper 80 MHz of the 160 MHz bandwidth. TheDocket No. 1002P24027W01Client Matter No. P24-027WO1NPCA primary channel of the sharing AP may be the lowest frequency 20 MHz channel that is outside of the operating bandwidth of the shared AP.

[0153] Figure 16 is a diagram showing how NPCA operation in a c-TDMA scenario can prevent the sharing AP from being able to receive a TXOP return frame from the shared AP, according to some embodiments.

[0154] As shown in the diagram, the sharing AP may transmit MU-RTS TXS frame 1605 to the shared AP in the primary channel to share a portion of the sharing AP’s TXOP with the shared AP. Responsive to receiving MU-RTS TXS frame 1605, the shared AP may transmit CTS frame 1610 to the sharing AP in the primary channel. Non-AP STA(s) associated with the shared AP (e.g., STA1-1 and STA1-2) may overhear CTS frame 1610. Through the MU-RTS TXS frame 1605 and CTS frame 1610 exchange, the shared AP may be allocated a portion of the sharing AP’s TXOP (this portion is depicted in the diagram as “Time shared by sharing AP”).

[0155] During its allocated portion of the TXOP, the shared AP may transmit (MU-)RTS frame 1615 to non-AP STA(s) associated with the shared AP (e.g., STA1-1 and STA1-2). Responsive to receiving (MU-)RTS frame 1615, the non-AP STA(s) associated with the shared AP may transmit CTS frame 1620 to the shared AP. The sharing AP may overhear (MU-)RTS frame 1615 and CTS frame 1620. Also, non-AP STA(s) associated with the sharing AP (e.g., STA2-2) may overhear (MU-)RTS frame 1615 and CTS frame 1620. The transmissions of (MU-)RTS frame 1615 and CTS frame 1620 may cause a NAV to be set at the sharing AP and NPCA-capable STA(s) associated with the sharing AP.

[0156] After exchanging (MU-)RTS frame 1615 and CTS frame 1620, the shared AP and the non-AP STA(s) associated with the shared AP may perform frame exchange 1625. Also, the sharing AP and the non-AP STAs associated with the sharing AP may perform NPCA in the NPCA primary channel based on overhearing (MU-)RTS frame 1615 and / or CTS frame 1620. For example, based on overhearing (MU-)RTS frame 1615 and / or CTS frame 1620, the sharing AP may switch channels to the NPCA primary channel and perform NPCA with the non-AP STAs associated with the sharing AP (e.g., NPCA operation 1630 with STA2-2) during a NPCA duration. Similarly, based on overhearing (MU-)RTS frame 1615 and / or CTS frame 1620, the non-AP STA(s) associated with the sharing AP may switch channels to the NPCA primary channel and perform NPCA with the sharing AP (e.g., NPCA operation 1635 with the sharing AP) during the NPCA duration.

[0157] It is assumed in this example that the shared AP and its associated non-AP STA(s) finish frame exchange 1625 early, before the portion of the TXOP allocated to the shared APDocket No. 1002P24027W01Client Matter No. P24-027WO1expires. Also, it is assumed that TXOP return is allowed. Thus, after finishing frame exchange 1625 early, the shared AP may transmit TXOP return frame 1640 to the sharing AP in the primary channel to return the TXOP to the sharing AP. However, since the sharing AP has switched channels to the NPCA primary channel, the shared AP is not able to recognize / receive TXOP return frame 1640. As a result, any time remaining in the TXOP goes unused.

[0158] In an embodiment, NPCA operation is prohibited during c-TDMA and / or other multi- AP coordination scenarios (e.g., coordinated beamforming, coordinated spatial reuse, and / or coordinated restricted target wake time scenarios). For example, NPCA may be prohibited regardless of whether the sharing AP allows the shared AP to return the TXOP or not. This means that the sharing AP will not perform NPCA during the portion of the TXOP allocated to the shared AP (e.g., during the duration indicated in the MU-RTS TXS frame that initiates the c- TDMA). The sharing AP may indicate to its associated non-AP STAs that NPCA operation is not allowed during c-TDMA or multi-AP coordination during a capabilities exchange with the non-AP STAs. In an embodiment, the indication that NPCA operation is not allowed during c- TDMA or multi-AP coordination is transmitted in the MU-RTS TXS frame that initiates the c- TDMA (e.g., in MU-RTS TXS frame 1605).

[0159] In an embodiment, the sharing AP transmits an indication of whether NPCA operation is allowed (or not allowed) during c-TDMA or other multi-AP coordination scenarios. For example, the sharing AP may transmit the indication in the common information field of the MU-RTS TXS frame that initiates the c-TDMA. In an embodiment, the indication may comprise a single bit, where the bit being set to a value of binary ‘0’ indicates that NPCA is allowed and the bit being set to a value of binary ‘ 1 ’ indicates that NPCA is not allowed (although it should be appreciated that the opposite convention is also possible). NPCA-capable non-AP STAs that receive the indication may enable NPCA or disable NPCA depending on the indication. For example, NPCA-capable non-AP STAs associated with the sharing AP that decode the indication bit as having a value of binary ‘0’ (NPCA is allowed) may be able to perform NPCA after overhearing a frame exchange in the shared AP’s BSS or another OBSS. However, in this case, if the shared AP attempts to transmit a TXOP return frame to the sharing AP, the sharing AP may not be able to receive it. However, NPCA will be allowed to be performed despite this risk. NPCA-capable non-AP STAs that decode the indication bit as having a value of binary ‘ 1’ (NPCA is not allowed) will temporarily disable NPCA and not perform NPCA even if an OBSS frame exchange (e.g., frame exchange in the shared AP’s BSS or another OBSS) occupies the primary channel. In a c-TDMA scenario, this ensures that the sharing AP will be able to receive a TXOP return frame transmitted by the shared AP.Docket No. 1002P24027W01Client Matter No. P24-027WO1

[0160] Figure 17 is a diagram showing a c-TDMA scenario where NPCA is indicated as being allowed, according to some embodiments.

[0161] As shown in the diagram, the sharing AP and the shared AP may perform frame exchange for c-TDMA 1705, which may include a frame exchange of MU-RTS TXS trigger frame (TF) 1710 and CTS frame 1715. MU-RTS TXS trigger frame 1710 may include an indication that NPCA is allowed during c-TDMA (e.g., the “NPCA available” field may be set to a value of binary ‘0’ to indicate this).

[0162] The shared AP and its associated non-AP STAs may perform frame exchange 1720, which may include a frame exchange of MU-RTS frame 1725 and CTS frame 1730. Frame exchange 1720 may cause a NAV to be set at the sharing AP and NPCA-capable STAs associated with the sharing AP. The shared AP and its associated non-AP STAs may then perform frame exchange 1760, which may include a frame exchange of data frame 1765 and an acknowledgement (ACK) frame 1770.

[0163] Since NPCA was indicated as being allowed, the sharing AP and NPCA-capable non- AP STAs associated with the sharing AP may perform NPCA upon overhearing frame exchange 1720. For example, the sharing AP and the non-AP STAs associated with the sharing AP may perform NPCA operation 1750 and NPCA operation 1740, respectively, during a NPCA duration.

[0164] It is noted that due to the NPCA operation in the sharing AP’s BSS, the sharing AP may not be able to receive TXOP return frame 1775 transmitted by the shared AP (as depicted by the “X” in the diagram).

[0165] Figure 18 is a diagram showing a c-TDMA scenario where NPCA is indicated as not being allowed, according to some embodiments.

[0166] As shown in the diagram, the sharing AP and the shared AP may perform frame exchange for c-TDMA 1805, which may include a frame exchange of MU-RTS TXS trigger frame (TF) 1810 and CTS frame 1815. MU-RTS TXS trigger frame 1810 may include an indication that NPCA is not allowed during c-TDMA (e.g., the “NPCA available” field may be set to a value of binary ‘ 1 ’ to indicate this).

[0167] The shared AP and its associated non-AP STAs may perform frame exchange 1820, which may include a frame exchange of MU-RTS frame 1825 and CTS frame 1830. Frame exchange 1820 may cause a NAV to be set at the sharing AP and NPCA-capable STAs associated with the sharing AP. The shared AP and its associated non-AP STAs may then perform frame exchange 1860, which may include a frame exchange of data frame 1865 and ACK frame 1870.Docket No. 1002P24027W01Client Matter No. P24-027WO1

[0168] Since NPCA was indicated as not being allowed, the sharing AP and NPCA-capable non-AP STAs associated with the sharing AP will not perform NPCA during the portion for the TXOP allocated to the shared AP. For example, the sharing AP and the non-AP STAs associated with the sharing AP will not perform NPCA operation 1850 and NPCA operation 1840 (as depicted by the “X”s in the diagram).

[0169] That is, NPCA operation is temporarily disabled in the sharing AP’s BSS during the portion of the sharing AP’s TXOP allocated to the shared AP. This allows the sharing AP to successfully receive TXOP return frame 1875 from the shared AP (as depicted by the smiley face in the diagram).

[0170] In an embodiment, NPCA is allowed during c-TDMA if TXOP return is not allowed, but NPCA operation is not allowed during c-TDMA if TXOP return is allowed. For example, if TXOP return is not allowed, NPCA-capable AP / STAs in the sharing AP’s BSS are allowed to perform NPCA during c-TDMA. However, if TXOP return is allowed, the NPCA-capable AP / STAs in the sharing AP’s BSS are not allowed to perform NPCA during c-TDMA. The indication of whether TXOP return is allowed can be shared / transmitted during a prior negotiation process between the sharing AP and the shared AP. Alternatively, the indication of whether TXOP return is allowed can be included in the MU-RTS TXS trigger frame that the sharing AP transmits to the shared AP to share the TXOP with the shared AP. NPCA-capable STAs of the sharing AP’s BSS that receive the indication that TXOP return is allowed may temporarily disable NPCA during the portion of the TXOP allocated to the shared AP.

[0171] Figure 19 is a diagram showing a c-TDMA scenario where TXOP return is allowed, according to some embodiments.

[0172] As shown in the diagram, the sharing AP and the shared AP may perform frame exchange for c-TDMA 1905, which may include a frame exchange of MU-RTS TXS trigger frame (TF) 1910 and CTS frame 1915. MU-RTS TXS trigger frame 1910 may include an indication that TXOP return is allowed.

[0173] The shared AP and its associated non-AP STAs may perform frame exchange 1920, which may include a frame exchange of MU-RTS frame 1925 and CTS frame 1930. Frame exchange 1920 may cause a NAV to be set at the sharing AP and NPCA-capable STAs associated with the sharing AP. The shared AP and its associated non-AP STAs may then perform frame exchange 1960, which may include a frame exchange of data frame 1965 and ACK frame 1970.

[0174] Since TXOP return is allowed, the sharing AP and NPCA-capable non-AP STAs associated with the sharing AP will not perform NPCA during the portion of the TXOP allocatedDocket No. 1002P24027W01Client Matter No. P24-027WO1to the shared AP. For example, the sharing AP and the non-AP STAs associated with the sharing AP will not perform NPCA operation 1950 and NPCA operation 1940 (as depicted by the “X”s in the diagram).

[0175] Since NCPA operation is disabled in the sharing AP’s BSS, the sharing AP may successfully receive TXOP return frame 1975 from the shared AP.

[0176] Figure 20 is a diagram showing a c-TDMA scenario where TXOP return is not allowed, according to some embodiments.

[0177] As shown in the diagram, the sharing AP and the shared AP may perform frame exchange for c-TDMA 2005, which may include a frame exchange of MU-RTS TXS trigger frame (TF) 2010 and CTS frame 2015. MU-RTS TXS trigger frame 2010 may include an indication that TXOP return is not allowed.

[0178] The shared AP and its associated non-AP STAs may perform frame exchange 2020, which may include a frame exchange of MU-RTS frame 2025 and CTS frame 2030. Frame exchange 2020 may cause a NAV to be set at the sharing AP and NPCA-capable STAs associated with the sharing AP. The shared AP and its associated non-AP STAs may then perform frame exchange 2060, which may include a frame exchange of data frame 2065 and ACK frame 2070.

[0179] Since TXOP return is not allowed, the sharing AP and NPCA-capable non-AP STAs associated with the sharing AP may perform NPCA upon overhearing frame exchange 2020. For example, the sharing AP and the non-AP STAs associated with the sharing AP may perform NPCA operation 2050 and NPCA operation 2040, respectively, during a NPCA duration.

[0180] It is noted that since TXOP return is not allowed, the shared AP will not transmit TXOP return frame 2075 to the sharing AP. Thus, the sharing AP does not need to be involved in the TXOP return process, and thus can freely perform NPCA, thereby increasing the network efficiency.

[0181] For purposes of illustration only, the technique to control NPCA operation has been primarily described herein in the context of a c-TDMA scenario. However, embodiments are not so limited. The technique may also be applied to other multi-AP coordination situations. For example, in a coordinated restricted target wake time (co-RTWT or c-RTWT) scenario, an AP and its associated non-AP STA(s) that are operating in protection mode to protect an OBSS AP’s restricted target wake time (rTWT) operation during the OBSS AP’s rTWT service period (SP) may encounter situations that could trigger NPCA operation. However, despite this, they may intentionally decide not to perform NPCA. In a coordinated beamforming (co-BF or c-BF) scenario or a coordinated spatial reuse (co-SR or c-SR) scenario, an AP and its associated non-Docket No. 1002P24027W01Client Matter No. P24-027WO1AP STA(s) may perform an initial control frame (ICF) and initial control response frame (ICR) exchange before performing the actual coordinated beamforming or spatial reuse. The purpose of this frame exchange is for enhanced multi-link single radio (EMLSR) and dynamic power save (DPS) non-AP STAs. However, an OBSS STA that overhears the frame exchange and participates in the coordinated beamforming or spatial reuse sequence may perform NPCA. With embodiments, this OBSS STA may intentionally decide not to perform NPCA.

[0182] Turning now to Figure 21, a method 2100 will be described for controlling NPCA during multi -AP coordination, in accordance with an example embodiment. The method 2100 may be performed by a first AP that operates a first BSS. The first AP may be implemented by a wireless device (e.g., wireless device 104).

[0183] Additionally, although shown in a particular order, in some embodiments the operations of the method 2100 (and the other methods shown in the other figures) may be performed in a different order. For example, although the operations of the method 2100 are shown in a sequential order, some of the operations may be performed in partially or entirely overlapping time periods.

[0184] At operation 2105, the first AP transmits, in the first BSS, an indication of whether NPCA is allowed in the first BSS during multi-AP coordination.

[0185] At operation 2110, the first AP performs multi-AP coordination with a second AP operating a second BSS that is different from the first BSS, wherein non-AP STAs belonging to the first BSS enable NPCA or disable NPCA during the multi-AP coordination with the second AP depending on the indication. In an embodiment, the multi-AP coordination with the second AP is c-TDMA. In an embodiment, the indication (mentioned in operation 2105) is transmitted in a MU-RTS TXS trigger frame. In an embodiment, the MU-RTS TXS trigger frame includes a common information field, wherein the indication is included in the common information field. In an embodiment, the indication is transmitted during a capabilities exchange in the first BSS.

[0186] In an embodiment, at operation 2115, the first AP may determine whether NPCA is allowed in the first BSS during the multi-AP coordination with the second AP. If NPCA is allowed (e.g., the indication (mentioned in operation 2105) indicates that NPCA is allowed in the first BSS during multi-AP coordination), the method may proceed to operation 2120. In an embodiment, at operation 2120, responsive to detecting an OBSS transmission in a primary channel of the first BSS during the multi-AP coordination with the second AP, the sharing AP performs NPCA with one or more of the non-AP STAs belonging to the first BSS in a NPCA primary channel of the first BSS. In an embodiment, the OBSS transmission is a transmissionDocket No. 1002P24027W01Client Matter No. P24-027WO1by the second BSS. In an embodiment, the OBSS transmission is a transmission by a third BSS that is different from the first BSS and the second BSS. Returning to operation 2115, if NPCA is not allowed (e.g., the indication (mentioned in operation 2105) indicates that NPCA is not allowed in the BSS during multi-AP coordination), the method may proceed to operation 2125. In an embodiment, at operation 2125, the first AP temporarily disables NPCA during the multi- AP coordination with the second AP, wherein the disabling causes the first AP to refrain from performing NPCA in the first BSS during the multi-AP coordination with the second AP even when an OBSS transmission occurs in the primary channel of the first BSS. In an embodiment (e.g., in a c-TDMA scenario), the first AP receives a TXOP return frame from the second AP during the multi-AP coordination with the second AP. The first AP may then resume a TXOP in response to receiving the TXOP return frame. In an embodiment, at operation 2130, the first AP enables NPCA after the multi-AP coordination with the second AP is over.

[0187] In an embodiment, the multi-AP coordination is any one of: coordinated beamforming, coordinated spatial reuse, and coordinated restricted target wake time.

[0188] Turning now to Figure 22, a method 2200 will be described for enabling or disabling NPCA during multi-AP coordination, in accordance with an example embodiment. The method 2200 may be performed by a (non-AP) STA belonging to a first BSS operated by a first AP. The STA may be implemented by a wireless device (e.g., wireless device 104).

[0189] At operation 2205, the STA receives, from the first AP, an indication of whether NPCA is allowed in the first BSS during multi-AP coordination.

[0190] At operation 2210, the STA enables or disables NPCA during a multi-AP coordination between the first AP and a second AP operating a second BSS depending on the indication. For example, the STA may enable NPCA if the indication received from the first AP indicates that NPCA is allowed or the STA may temporarily disable NPCA (during the multi-AP coordination between the first AP and the second AP) if the indication received from the first AP indicates that NPCA is not allowed. In an embodiment, the multi-AP coordination between the first AP and the second AP is c-TDMA. In an embodiment, the indication (mentioned in operation 2205) is received in a MU-RTS TXS trigger frame. In an embodiment, the MU-RTS TXS trigger frame includes a common information field, wherein the indication is included in the common information field. In an embodiment, the indication is received during a capabilities exchange in the first BSS.

[0191] In an embodiment, if NPCA is enabled (e.g., because the indication indicates that NPCA is allowed in the first BSS during multi-AP coordination), the method may proceed to operation 2220. In an embodiment, at operation 2220, responsive to detecting an OBSSDocket No. 1002P24027W01Client Matter No. P24-027WO1transmission in a primary channel of the first BSS during the multi-AP coordination between the first AP and the second AP, the STA performs NPCA with the first AP in a NPCA primary channel of the first BSS. In an embodiment, the OBSS transmission is a transmission by the second BSS. In an embodiment, the OBSS transmission is a transmission by a third BSS that is different from the first BSS and the second BSS. Otherwise, if NPCA is not enabled (e.g., because the indication indicates that NPCA is not allowed in the first BSS during multi-AP coordination), the method may proceed to operation 2225. In an embodiment, at operation 2225, the STA refrains from performing NPCA in the first BSS during the multi-AP coordination between the first AP and the second AP even when an OBSS transmission occurs in a primary channel of the first BSS. In an embodiment, at operation 2230, the STA enables NPCA after the multi-AP coordination between the first AP and the second AP is over.

[0192] In an embodiment, the multi-AP coordination between the first AP and the second AP is any one of: coordinated beamforming, coordinated spatial reuse, and coordinated restricted target wake time.

[0193] Turning now to Figure 23, a method 2300 will be described for performing multi-AP coordination, in accordance with an example embodiment. The method 2300 may be performed by a first AP operating a first BSS. The first AP may be implemented by a wireless device (e.g., wireless device 104).

[0194] At operation 2305, the first AP performs multi-AP coordination with a second AP operating a second BSS that is different rom the first BSS, wherein the first AP temporarily disables NPCA during the multi-AP coordination with the second AP, wherein the disabling causes the first AP to refrain from performing NPCA in the first BSS during the multi-AP coordination with the second AP even when an OBSS transmission occurs in a primary channel of the first BSS.

[0195] In an embodiment (e.g., where the multi-AP coordination with the second AP is c- TDMA), at operation 2310, the first AP receives a TXOP return frame from the second AP during the multi-AP coordination with the second AP (e.g., during a portion of the first AP’s TXOP allocated to the second AP).

[0196] In an embodiment, at operation 2315, the first AP resumes a TXOP in response to receiving the TXOP return frame.

[0197] In an embodiment, at operation 2320, the first AP enables NPCA after the multi-AP coordination with the second AP is over (e.g., after a portion of the first AP’s TXOP allocated to the second AP expires).Docket No. 1002P24027W01Client Matter No. P24-027WO1

[0198] In an embodiment, the multi-AP coordination with the second AP is any one of: coordinated beamforming, coordinated spatial reuse, and coordinated restricted target wake time.

[0199] Turning now to Figure 24, a method 2400 will be described for disabling NPCA during multi-AP coordination, in accordance with an example embodiment. The method 2400 may be performed by a (non-AP) STA that belongs to a first BSS operated by a first AP. The STA may be implemented by a wireless device (e.g., wireless device 104).

[0200] At operation 2405, the STA temporarily disables NPCA during a multi-AP coordination between the first AP and a second AP operating a second BSS that is different rom the first BSS, wherein the disabling causes the STA to refrain from performing NPCA in the first BSS even when an OBSS transmission occurs in a primary channel of the first BSS.

[0201] In an embodiment, at operation 2410, the STA enables NPCA after the multi-AP coordination between the first AP and the second AP is over.

[0202] In an embodiment, the multi-AP coordination between the first AP and the second AP is any one of: c-TDMA, coordinated beamforming, coordinated spatial reuse, and coordinated restricted target wake time.

[0203] Although many of the solutions and techniques provided herein have been described with reference to a WLAN system, it should be understood that these solutions and techniques are also applicable to other network environments, such as cellular telecommunication networks, wired networks, etc. In some embodiments, the solutions and techniques provided herein may be or may be embodied in an article of manufacture in which a non-transitory machine-readable medium (such as microelectronic memory) has stored thereon instructions which program one or more data processing components (generically referred to here as a “processor” or “processing unit”) to perform the operations described herein. In other embodiments, some of these operations might be performed by specific hardware components that contain hardwired logic (e.g., dedicated digital filter blocks and state machines). Those operations might alternatively be performed by any combination of programmed data processing components and fixed hardwired circuit components.

[0204] 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 includeDocket No. 1002P24027W01Client Matter No. P24-027WO1one or more other hardware or software elements, including a network interface, a display device, etc.

[0205] 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.

[0206] 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.

[0207] The present disclosure also relates to an apparatus for performing the operations herein. This apparatus can be specially constructed for the intended purposes, or it can include a general -purpose computer selectively activated or reconfigured by a computer program stored in the computer. For example, a computer system or other data processing system may carry out the computer-implemented methods described herein in response to its processor executing a computer program (e.g., a sequence of instructions) contained in a memory or other non- transitory machine-readable storage medium. Such a computer program can be stored in a computer readable storage medium, such as, but not limited to, any type of disk including floppy disks, optical disks, CD-ROMs, and magnetic-optical disks, read-only memories (ROMs), 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.

[0208] 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 willDocket No. 1002P24027W01Client Matter No. P24-027WO1appear 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.

[0209] 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.

[0210] 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. 1002P24027W01Client Matter No. P24-027WO1

Claims

CLAIMSWhat is claimed is:

1. A method performed by a first access point (AP) operating a first basic service set (BSS) to control non-primary channel access (NPCA) operation in the first BSS when the first AP performs multi-AP coordination with a second AP operating a second BSS that is different from the first BSS, the method comprising: transmitting an indication of whether NPCA is allowed in the first BSS during multi-AP coordination; and performing multi-AP coordination with the second AP, wherein non-AP stations (STAs) belonging to the first BSS enable NPCA or disable NPCA during the multi-AP coordination with the second AP depending on the indication.

2. The method of claim 1, wherein the multi-AP coordination with the second AP is coordinated time division multiple access (c-TDMA).

3. The method of claim 2, wherein the indication is transmitted in a multi-user request-to- send transmission opportunity sharing (MU-RTS TXS) trigger frame.

4. The method of claim 3, wherein the MU-RTS TXS trigger frame includes a common information field, wherein the indication is included in the common information field.

5. The method of claim 1, wherein the indication is transmitted during a capabilities exchange in the first BSS.

6. The method of claim 1, wherein the indication indicates that NPCA is allowed in the first BSS during multi-AP coordination.

7. The method of claim 6, further comprising: responsive to detecting an overlapping basic service set (OBSS) transmission in a primary channel of the first BSS during the multi-AP coordination with the second AP, performing NPCA with one or more of the non-AP STAs belonging to the first BSS in a NPCA primary channel of the first BSS.

8. The method of claim 7, wherein the OBSS transmission is a transmission by the second BSS.Docket No. 1002P24027W01Client Matter No. P24-027WO19. The method of claim 7, wherein the OBSS transmission is a transmission by a third BSS that is different from the first BSS and the second BSS.

10. The method of claim 1, wherein the indication indicates that NPCA is not allowed in the BSS during multi-AP coordination.

11. The method of claim 10, further comprising: temporarily disabling NPCA during the multi-AP coordination with the second AP, wherein the disabling causes the first AP to refrain from performing NPCA in the first BSS during the multi-AP coordination with the second AP even when an OBSS transmission occurs in a primary channel of the first BSS.

12. The method of claim 11, further comprising: receiving a transmission opportunity (TXOP) return frame from the second AP during the multi-AP coordination with the second AP; and resuming a TXOP in response to receiving the TXOP return frame.

13. The method of claim 11, further comprising: enabling NPCA after the multi-AP coordination with the second AP is over.

14. The method of claim 1, wherein the multi-AP coordination is any one of: coordinated beamforming, coordinated spatial reuse, and coordinated restricted target wake time.

15. A method performed by a station (STA) belonging to a first basic service set (BSS) operated by a first access point (AP), the method comprising: receiving, from the first AP, an indication of whether NPCA is allowed in the first BSS during multi-AP coordination; and enabling or disabling NPCA during a multi-AP coordination between the first AP and a second AP operating a second BSS depending on the indication.

16. The method of claim 15, wherein the multi-AP coordination between the first AP and the second AP is coordinated time division multiple access (c-TDMA).

17. The method of claim 16, wherein the indication is received in a multi-user request-to- send transmission opportunity sharing (MU-RTS TXS) trigger frame.

18. The method of claim 17, the MU-RTS TXS trigger frame includes a common information field, wherein the indication is included in the common information field.Docket No. 1002P24027W01Client Matter No. P24-027WO119. The method of claim 15, wherein the indication is received during a capabilities exchange in the first BSS.

20. The method of claim 15, wherein the STA enables NPCA during the multi-AP coordination between the first AP and the second AP because the indication indicates that NPCA is allowed in the first BSS during multi-AP coordination.

21. The method of claim 20, further comprising: responsive to detecting an overlapping basic service set (OBSS) transmission in a primary channel of the first BSS during the multi-AP coordination between the first AP and the second AP, performing NPCA with the first AP in a NPCA primary channel of the first BSS.

22. The method of claim 21, wherein the OBSS transmission is a transmission by the second BSS.

23. The method of claim 21, wherein the OBSS transmission is a transmission by a third BSS that is different from the first BSS and the second BSS.

24. The method of claim 15, wherein the STA temporarily disables NPCA during the multi- AP coordination between the first AP and the second AP because the indication indicates that NPCA is not allowed in the first BSS during multi-AP coordination, wherein the method further comprises: refraining from performing NPCA in the first BSS even when an OBSS transmission occurs in a primary channel of the first BSS.

25. The method of claim 24, further comprising: enabling NPCA after the multi-AP coordination between the first AP and the second AP is over.

26. The method of claim 15, wherein the multi-AP coordination between the first AP and the second AP is any one of: coordinated beamforming, coordinated spatial reuse, and coordinated restricted target wake time.Docket No. 1002P24027W01Client Matter No. P24-027WO127. A method performed by a first access point (AP) operating a first basic service set (BSS) to perform multi-AP coordination with a second AP operating a second BSS that is different from the first BSS, the method comprising: performing multi-AP coordination with the second AP, wherein the first AP temporarily disables NPCA during the multi-AP coordination with the second AP, wherein the disabling causes the first AP to refrain from performing NPCA in the first BSS during the multi-AP coordination with the second AP even when an OBSS transmission occurs in a primary channel of the first BSS.

28. The method of claim 27, wherein the multi-AP coordination with the second AP is coordinated time division multiple access (c-TDMA).

29. The method of claim 28, further comprising: receiving a transmission opportunity (TXOP) return frame from the second AP during the multi-AP coordination with the second AP; and resuming a TXOP in response to receiving the TXOP return frame.

30. The method of claim 27, further comprising: enabling NPCA after the multi-AP coordination with the second AP is over.

31. The method of claim 27, wherein the multi-AP coordination with the second AP is any one of: coordinated beamforming, coordinated spatial reuse, and coordinated restricted target wake time.

32. A method performed by a station (STA) belonging to a first basic service set (BSS) operated by a first access point (AP), the method comprising: temporarily disabling NPCA during a multi-AP coordination between the first AP and a second AP operating a second BSS, wherein the disabling causes the STA to refrain from performing NPCA in the first BSS even when an OBSS transmission occurs in a primary channel of the first BSS.

33. The method of claim 32, further comprising: enabling NPCA after the multi-AP coordination between the first AP and the second AP is over.Docket No. 1002P24027W01Client Matter No. P24-027WO134. The method of claim 32, wherein the multi-AP coordination between the first AP and the second AP is any one of: coordinated time division multiple access, coordinated beamforming, coordinated spatial reuse, and coordinated restricted target wake time.

35. A wireless device comprising: a radio frequency transceiver; a memory device storing a set of instructions; and a processor coupled to the memory device, wherein the set of instructions, when executed by the processor, causes the wireless device to perform the method of any one of claims 1-14.

36. A wireless device comprising: a radio frequency transceiver; a memory device storing a set of instructions; and a processor coupled to the memory device, wherein the set of instructions, when executed by the processor, causes the wireless device to perform the method of any one of claims 15-26.

37. A wireless device comprising: a radio frequency transceiver; a memory device storing a set of instructions; and a processor coupled to the memory device, wherein the set of instructions, when executed by the processor, causes the wireless device to perform the method of any one of claims 27-31.

38. A wireless device comprising: a radio frequency transceiver; a memory device storing a set of instructions; and a processor coupled to the memory device, wherein the set of instructions, when executed by the processor, causes the wireless device to perform the method of any one of claims 32-34.Docket No. 1002P24027W01Client Matter No. P24-027WO1

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