Non-primary channel access (NPCA) operation

Abstract

An access point (AP) determines that a physical layer (PHY) protocol data unit (PPDU) being received via a primary channel (PCH) comprises an inter-basic service set (inter-BSS) PPDU. The AP obtains, based on the PPDU, a value of a duration associated with the PPDU. Based on the determining: the AP does not update a basic network allocation vector (NAV) timer with the value of the duration, and the AP transmits, via the PCH and during the duration, a frame instructing a station (STA), associated with the AP, to switch from the PCH to a non-primary channel access (NPCA) PCH.

Description

PCT / US25 / 48151 26 September 2025 (26.09.2025)Docket No.: 24-3044 PCTTITLENON-PRIMARY CHANNEL ACCESS (NPCA) OPERATION CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application No. 63 / 699,999, filed September 27, 2024, and U.S. Provisional Application No. 63 / 757,830, filed February 13, 2025, which are hereby incorporated by reference in their entireties.BRIEF DESCRIPTION OF THE DRAWINGS

[0002] Examples of several of the various embodiments of the present disclosure are described herein with reference to the drawings.

[0003] FIG. 1 illustrates example wireless communication networks in which embodiments of the present disclosure may be implemented.

[0004] FIG. 2 is a block diagram illustrating example implementations of a station (STA) and an access point (AP).

[0005] FIG. 3 illustrates an example of a Medium Access Control (MAC) frame format.

[0006] FIG. 4 illustrates an example trigger frame.

[0007] FIG. 5 illustrates an example multi-user request to send (MU-RTS) trigger frame.

[0008] FIG. 6 illustrates an example common info field.

[0009] FIG. 7 illustrates an example of a Request-to-Send (RTS)ZCIear-to-Send (CTS) procedure.

[0010] FIG. 8 is an example that illustrates an MU-RTS / CTS procedure.

[0011] FIG. 9 is an example that illustrates non-primary channel access (NPCA) operation.

[0012] FIG. 10 illustrates virtual and physical carrier sense (CS) functions associated with primary and secondary channels for NPCA operation and non-NPCA operation.

[0013] FIG. 11 shows an example that illustrates NPCA operation.

[0014] FIG. 12 shows another example that illustrates NPCA operation.

[0015] FIG. 13 shows another example that illustrates NPCA operation.

[0016] FIG. 14 illustrates a problem that may arise during NPCA operation.

[0017] FIG. 15 shows an example that illustrates an example NPCA operation according to an embodiment.

[0018] FIG. 16 shows another example that illustrates another example NPCA operation according to an embodiment.

[0019] FIG. 17 shows another example that illustrates another example NPCA operation according to an embodiment.

[0020] FIG. 18 illustrates an example process according to an embodiment.

[0021] FIG. 19 illustrates another example process according to an embodiment.

[0022] FIG. 20 illustrates another example process according to an embodiment.PCT / US25 / 48151 26 September 2025 (26.09.2025)Docket No.: 24-3044 PCT

[0023] FIG. 21 illustrates another example process according to an embodiment.DETAILED DESCRIPTION

[0024] In the present disclosure, various embodiments are presented as examples of how the disclosed techniques may be implemented and / or how the disclosed techniques may be practiced in environments and scenarios. It will be apparent to persons skilled in the relevant art that various changes in form and detail can be made therein without departing from the scope. After reading the description, it will be apparent to one skilled in the relevant art how to implement alternative embodiments. The present embodiments may not be limited by any of the described exemplary embodiments. The embodiments of the present disclosure will be described with reference to the accompanying drawings. Limitations, features, and / or elements from the disclosed example embodiments may be combined to create further embodiments within the scope of the disclosure. Any figures which highlight the functionality and advantages are presented for example purposes only. The disclosed architecture is sufficiently flexible and configurable, such that it may be utilized in ways other than those shown. For example, the actions listed in any flowchart may be re-ordered or only optionally used in some embodiments.

[0025] Embodiments may be configured to operate as needed. The disclosed mechanism may be performed when certain criteria are met, for example, in a station, an access point, a radio environment, a network, a combination of the above, and / or the like. Example criteria may be based, at least in part, on for example, wireless device or network node configurations, traffic load, initial system set up, packet sizes, traffic characteristics, a combination of the above, and / or the like. When the one or more criteria are met, various example embodiments may be applied. Therefore, it may be possible to implement example embodiments that selectively implement disclosed protocols.

[0026] In this disclosure, "a” and “an” and similar phrases are to be interpreted as “at least one” and “one or more." Similarly, any term that ends with the suffix “(s)" is to be interpreted as “at least one" and “one or more." In this disclosure, the term “may" is to be interpreted as “may, for example." In other words, the term “may” is indicative that the phrase following the term “may” is an example of one of a multitude of suitable possibilities that may, or may not, be employed by one or more of the various embodiments. The terms “comprises” and “consists of’, as used herein, enumerate one or more components of the element being described. The term “comprises” is interchangeable with “includes” and does not exclude unenumerated components from being included in the element being described. By contrast, “consists of’ provides a complete enumeration of the one or more components of the element being described. The term “based on”, as used herein, may be interpreted as “based at least in part on” rather than, for example, “based solely on”. The term “and / or” as used herein represents any possible combination of enumerated elements. For example, “A, B, and / or C” may represent A; B; C; A and B; A and C; B and C; or A, B, and C.PCT / US25 / 48151 26 September 2025 (26.09.2025)Docket No.: 24-3044 PCT

[0027] If A and B are sets and every element of A is an element of B, A is called a subset of B. In this specification, only non-empty sets and subsets are considered. For example, possible subsets of B = {STA1 , STA2} are: {STA1}, {STA2}, and {STA1, STA2}. The phrase “based on” (or equally “based at least on”) is indicative that the phrase following the term “based on” is an example of one of a multitude of suitable possibilities that may, or may not, be employed to one or more of the various embodiments. The phrase “in response to” (or equally “in response at least to”) is indicative that the phrase following the phrase “in response to” is an example of one of a multitude of suitable possibilities that may, or may not, be employed to one or more of the various embodiments. The phrase “depending on” (or equally “depending at least to”) is indicative that the phrase following the phrase “depending on” is an example of one of a multitude of suitable possibilities that may, or may not, be employed to one or more of the various embodiments. The phrase “employing / using” (or equally “employing / using at least") is indicative that the phrase following the phrase “employing / using” is an example of one of a multitude of suitable possibilities that may, or may not, be employed to one or more of the various embodiments.

[0028] The term configured may relate to the capacity of a device whether the device is in an operational or non-operational state. Configured may refer to specific settings in a device that effect the operational characteristics of the device whether the device is in an operational or non-operational state. In other words, the hardware, software, firmware, registers, memory values, and / or the like may be “configured” within a device, whether the device is in an operational or nonoperational state, to provide the device with specific characteristics. Terms such as “a control message to cause in a device” may mean that a control message has parameters that may be used to configure specific characteristics or may be used to implement certain actions in the device, whether the device is in an operational or non-operational state.

[0029] In this disclosure, parameters (or equally called, fields, or Information elements: lEs) may comprise one or more information objects, and an information object may comprise one or more other objects. For example, if parameter (IE) N comprises parameter (IE) M, and parameter (IE) M comprises parameter (IE) K, and parameter (IE) K comprises parameter (information element) J. Then, for example, N comprises K, and N comprises J. In an example embodiment, when one or more messages / frames comprise a plurality of parameters, it implies that a parameter in the plurality of parameters is in at least one of the one or more messages / frames but does not have to be in each of the one or more messages / frames.

[0030] Many features presented are described as being optional through the use of “may” or the use of parentheses. For the sake of brevity and legibility, the present disclosure does not explicitly recite each and every permutation that may be obtained by choosing from the set of optional features. The present disclosure is to be interpreted as explicitly disclosing all such permutations. For example, a system described as having three optional features may be embodied in seven ways, namely with just one of the three possible features, with any two of the three possible features or with three of the three possible features.PCT / US25 / 48151 26 September 2025 (26.09.2025)Docket No.: 24-3044 PCT

[0031] Many of the elements described in the disclosed embodiments may be implemented as modules. A module is defined here as an element that performs a defined function and has a defined interface to other elements. The modules described in this disclosure may be implemented in hardware, software in combination with hardware, firmware, wetware (e.g., hardware with a biological element) or a combination thereof, which may be behaviorally equivalent. For example, modules may be implemented as a software routine written in a computer language configured to be executed by a hardware machine (such as C, C++, Fortran, Java, Basic, Matlab or the like) or a modeling / simulation program such as Simulink, Stateflow, GNU Octave, or LabVIEWMathScript. It may be possible to implement modules using physical hardware that incorporates discrete or programmable analog, digital and / or quantum hardware. Examples of programmable hardware comprise: computers, microcontrollers, microprocessors, application-specific integrated circuits (ASICs); field programmable gate arrays (FPGAs); and complex programmable logic devices (CPLDs). Computers, microcontrollers, and microprocessors are programmed using languages such as assembly, C, C++, or the like. FPGAs, ASICs and CPLDs are often programmed using hardware description languages (HDL) such as VHSIC hardware description language (VHDL) or Verilog that configure connections between internal hardware modules with lesser functionality on a programmable device. The mentioned technologies are often used in combination to achieve the result of a functional module.

[0032] FIG. 1 illustrates example wireless communication networks in which embodiments of the present disclosure may be implemented.

[0033] As shown in FIG. 1, the example wireless communication networks may include an Institute of Electrical and Electronic Engineers (IEEE) 802.11 (WLAN) infra-structure network 102. WLAN infra-structure network 102 may include one or more basic service sets (BSSs) 110 and 120 and a distribution system (DS) 130.

[0034] BSS 110-1 and 110-2 each includes a set of an access point (AP or AP STA) and at least one station (STA or non-AP STA). For example, BSS 110-1 includes an AP 104-1 and a STA 106-1, and BSS 110-2 includes an AP 104-2 and STAs 106-2 and 106-3. The AP and the at least one STA in a BSS perform an association procedure to communicate with each other.

[0035] DS 130 may be configured to connect BSS 110-1 and BSS 110-2. As such, DS 130 may enable an extended service set (ESS) 150. Within ESS 150, APs 104-1 and 104-2 are connected via DS 130 and may have the same service set identification (SSID).

[0036] WLAN infra-structure network 102 may be coupled to one or more external networks. For example, as shown in FIG. 1, WLAN infra-structure network 102 may be connected to another network 108 (e.g., 802.X) via a portal 140. Portal 140 may function as a bridge connecting DS 130 of WLAN infra-structure network 102 with the other network 108.

[0037] The example wireless communication networks illustrated in FIG. 1 may further include one or more ad-hoc networks or independent BSSs (IBSSs). An ad-hoc network or IBSS is a network that includes aPCT / US25 / 48151 26 September 2025 (26.09.2025)Docket No.: 24-3044 PCT plurality of STAs that are within communication range of each other. The plurality of STAs are configured so that they may communicate with each other using direct peer-to-peer communication (i.e. , not via an AP).

[0038] For example, in FIG. 1, STAs 106-4, 106-5, and 106-6 may be configured to form a first IBSS 112- 1. Similarly, STAs 106-7 and 106-8 may be configured to form a second IBSS 112-2. Since an IBSS does not include an AP, it does not include a centralized management entity. Rather, STAs within an IBSS are managed in a distributed manner. STAs forming an IBSS may be fixed or mobile.

[0039] A STA as a predetermined functional medium may include a medium access control (MAC) layer that complies with an IEEE 802.11 standard. A physical layer interface for a radio medium may be used among the APs and the non-AP stations (STAs). The STA may also be referred to using various other terms, including mobile terminal, wireless device, wireless transmit / receive unit (WTRU), user equipment (UE), mobile station (MS), mobile subscriber unit, or user. For example, the term "user" may be used to denote a STA participating in uplink Multi-user Multiple Input, Multiple Output (MU MIMO) and / or uplink Orthogonal Frequency Division Multiple Access (OFDMA) transmission.

[0040] A physical layer (PHY) protocol data unit (PPDU) may be a composite structure that includes a PHY preamble and a payload in the form of a PHY service data unit (PSDU). For example, the PSDU may include a PHY preamble and header and / or one or more MAC protocol data units (MPDUs). The information provided in the PHY preamble may be used by a receiving device to decode the subsequent data in the PSDU. In instances in which PPDUs are transmitted over a bonded channel (channel formed through channel bonding), the preamble fields may be duplicated and transmitted in each of the multiple component channels. The PHY preamble may include both a legacy portion (or “legacy preamble”) and a non-legacy portion (or “non-legacy preamble"). The legacy preamble may be used for packet detection, automatic gain control and channel estimation, among other uses. The legacy preamble also may generally be used to maintain compatibility with legacy devices. The format of, coding of, and information provided in the non-legacy portion of the preamble is based on the particular IEEE 802.11 protocol to be used to transmit the payload.

[0041] A frequency band may include one or more sub-bands or frequency channels. For example, PPDUs conforming to the IEEE 802.11n, 802.11ac, 802.11ax and / or 802.11be standard amendments may be transmitted over the 2.4 GHz, 5 GHz, and / or 6 GHz bands, each of which may be divided into multiple 20 MHz channels. The PPDUs may be transmitted over a physical channel having a minimum bandwidth of 20 MHz. Larger channels may be optionally formed through channel bonding of a primary 20 MHz channel and one or more 20 MHz secondary channels. For example, PPDUs may be transmitted over physical channels having bandwidths of 40 MHz, 80 MHz, 160 MHz, or 320 MHz by bonding together a primary 20 MHz channel and 1, 3, 7, or 15 secondary channel respectively. The primary channel is a common channel operation for all STAs where management frames are sent by the AP to ensure that all STAs (regardless of channel bonding support) can receive.PCT / US25 / 48151 26 September 2025 (26.09.2025)Docket No.: 24-3044 PCT

[0042] FIG. 2 is a block diagram illustrating example implementations of a STA 210 and an AP 260. As shown in FIG. 2, STA 210 may include at least one processor 220, a memory 230, and at least one transceiver 240. AP 260 may include at least one processor 270, a memory 280, and at least one transceiver 290. Processor 220 / 270 may be operatively connected to memory 230 / 280 and / or to transceiver 240 / 290.

[0043] Processor 220 / 270 may implement functions of the PHY layer, the MAC layer, and / or the logical link control (LLC) layer of the corresponding device (STA 210 or AP 260). Processor 220 / 270 may include one or more processors and / or one or more controllers. The one or more processors and / or one or more controllers may comprise, for example, a general-purpose processor, a digital signal processor (DSP), a microcontroller, an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), a logic circuit, or a chipset, for example.

[0044] Memory 230 / 280 may include a read-only memory (ROM), a random-access memory (RAM), a flash memory, a memory card, a storage medium, and / or other storage unit. Memory 230 / 280 may comprise one or more non-transitory computer readable mediums. Memory 230 / 280 may store computer program instructions or code that may be executed by processor 220 / 270 to carry out one or more of the operations / embodiments discussed in the present application. Memory 230 / 280 may be implemented (or positioned) within processor 220 / 270 or external to processor 220 / 270. Memory 230 / 280 may be operatively connected to processor 220 / 270 via various means known in the art.

[0045] Transceiver 240 / 290 may be configured to transmit / receive radio signals. In an embodiment, transceiver 240 / 290 may implement a PHY layer of the corresponding device (STA 210 or AP 260). In an embodiment, STA 210 and / or AP 260 may be a multi-link device (MLD), that is a device capable of operating over multiple links as defined by the IEEE 802.11 standard. As such, STA 210 and / or AP 260 may each implement multiple PHY layers. The multiple PHY layers may be implemented using one or more of transceivers 240 / 290.

[0046] FIG. 3 illustrates an example format of a MAC frame. In operation, a STA may construct a subset of MAC frames for transmission and may decode a subset of received MAC frames upon validation. The particular subsets of frames that a STA may construct and / or decode may be determined by the functions supported by the STA. A STA may validate a received MAC frame using the frame check sequence (FCS) contained in the frame and may interpret certain fields from the MAC headers of all frames.

[0047] As shown in FIG. 3, a MAC frame includes a MAC header, a variable length frame body, and a frame check sequence (FCS).

[0048] The MAC header includes a frame control field, an optional duration / ID field, address fields, an optional sequence control field, an optional QoS control field, and an optional HT control field.

[0049] The frame control field includes the following subfields: protocol version, type, subtype, “To DS”, “From DS”, “More Fragments”, retry, power management, “More Data , protected frame, and +HTC.PCT / US25 / 48151 26 September 2025 (26.09.2025)Docket No.: 24-3044 PCT

[0050] The protocol version subfield is invariant in size and placement across all revisions of the IEEE 802.11 standard. The value of the protocol version subfield is 0 for MAC frames.

[0051] The type and subtype subfields together identify the function of the MAC frame. There are three frame types: control, data, and management. Each of the frame types has several defined subtypes. Bits within the subtype subfield are used to indicate a specific modification of the basic data frame (subtype 0). For example, in data frames, the most significant bit (MSB) of the subtype subfield, bit 7 (B7) of the frame control field, is defined as the QoS subfield. When the QoS subfield is set to 1 , it indicates a QoS data frame, which is a data frame that contains a QoS control field in its MAC header. The second MSB of the subtype field, bit 6 (B6) of the frame control field, when set to 1 in data subtypes, indicates a data frame that contain no frame body field.

[0052] The "To DS” subfield indicates whether a data frame is destined to the distribution system (DS). The "From DS” subfield indicates whether a data frame originates from the DS.

[0053] The "More Fragments” subfield is set to 1 in all data or management frames that have another fragment to follow the MAC service data unit (MSDU) or MAC management protocol data unit (MMPDll) carried by the MAC frame. The "More Fragments” subfield is set to 0 in all other frames in which the "More Fragments” subfield is present.

[0054] The retry subfield is set to 1 in any data or management frame that is a retransmission of an earlier frame. It is set to 0 in all other frames in which the retry subfield is present. A receiving STA uses this indication to aid it in the process of eliminating duplicate frames. These rules do not apply for frames sent by a STA under a block agreement.

[0055] The power management subfield is used to indicate the power management mode of a STA.

[0056] The "More Data” subfield indicates to a STA in power save (PS) mode that bufferable units (BUs) are buffered for that STA at the AP. The “More Data” subfield is valid in individually addressed data or management frames transmitted by an AP to a STA in PS mode. The "More Data" subfield is set to 1 to indicate that at least one additional buffered BU is present for the STA.

[0057] The protected frame subfield is set to 1 if the frame body field contains information that has been processed by a cryptographic encapsulation algorithm.

[0058] The +HTC subfield indicates that the MAC frame contains an HT control field.

[0059] The duration / ID field of the MAC header indicates various contents depending on the frame type and subtype and the QoS capabilities of the sending STA. For example, in control frames of the power save poll (PS-Poll) subtype, the duration / ID field carries an association identifier (AID) of the STA that transmitted the frame in the 14 least significant bits (LSB), with the 2 most significant bits (MSB) set to 1. In other frames sent by STAs, the duration / ID field contains a duration value (in microseconds) which is used by a recipient to update a network allocation vector (NAV). The NAV is a counter that indicates to a STA an amount of time during which the STA must defer from accessing the shared medium.PCT / US25 / 48151 26 September 2025 (26.09.2025)Docket No.: 24-3044 PCT

[0060] Up to four address fields may be present in the MAC frame format. The address fields are used to indicate the basic service set identifier (BSSID), source address (SA), destination address (DA), transmitting address (TA), and receiving address (RA). Certain frames may not contain some of the address fields. Certain address field usage may be specified by the relative position of the address field (1-4) within the MAC header, independent of the type of address present in that field. Specifically, the address 1 field always identifies the intended receiver(s) of the frame, and the address 2 field, where present, always identifies the transmitter of the frame.

[0061] The sequence control field includes two subfields, a sequence number subfield and a fragment number subfield. The sequence number subfield in data frames indicates the sequence number of the MSDU (if not in an Aggregated MSDU (A-MSDU)) or A-MSDU. The sequence number subfield in management frames indicates the sequence number of the frame. The fragment number subfield indicates the number of each fragment of an MSDU or MMPDU. The fragment number is set to 0 in the first or only fragment of an MSDU or MMPDU and is incremented by one for each successive fragment of that MSDU or MMPDU. The fragment number is set to 0 in a MAC protocol data unit (MPDU) containing an A-MSDU, or in an MPDU containing an MSDU or MMPDU that is not fragmented. The fragment number remains constant in all retransmissions of the fragment.

[0062] The QoS control field identifies the traffic category (TC) or traffic stream (TS) to which the MAC frame belongs. The QoS control field may also indicate various other QoS related, A-MSDU related, and mesh- related information about the frame. This information can vary by frame type, frame subtype, and type of transmitting STA. The QoS control field is present in all data frames in which the QoS subfield of the subtype subfield is equal to 1.

[0063] The HT control field is present in QoS data, QoS null, and management frames as determined by the +HTC subfield of the frame control field.

[0064] The frame body field is a variable length field that contains information specific to individual frame types and subtypes. The frame body may include one or more MSDUs or MMPDUs. The minimum length of the frame body is 0 octets.

[0065] The FCS field contains a 32-bit Cyclic Redundancy Check (CRC) code. The FCS field value is calculated over all of the fields of the MAC header and the frame body field.

[0066] FIG. 4 illustrates an example trigger frame 400. Trigger frame 400 may correspond to a basic trigger frame as defined in the existing IEEE 802.11 ax standard amendment. Trigger frame 400 may be used by an AP to allocate resources for and solicit one or more TB PPDU transmissions from one or more STAs. Trigger frame 400 may also carry other information required by a responding STA to transmit a TB PPDU to the AP.

[0067] As shown in FIG. 4, trigger frame 400 includes a Frame Control field, a Duration field, a receiver address (RA) field, a transmitter address (TA) field, a Common Info field, a User List Info field, a Padding field, and an FCS field.PCT / US25 / 48151 26 September 2025 (26.09.2025)Docket No.: 24-3044 PCT

[0068] The Frame Control field includes the following subfields: protocol version, type, subtype, To DS, From DS, more fragments, retry, power management, more data, protected frame, and +HTC.

[0069] The Duration field indicates various contents depending on frame type and subtype and the QoS capabilities of the sending STA. For example, in control frames of the power save poll (PS-Poll) subtype, the Duration field carries an association identifier (AID) of the STA that transmitted the frame in the 14 least significant bits (LSB), and the 2 most significant bits (MSB) are both set to 1. In other frames sent by STAs, the Duration field contains a duration value (in microseconds) which is used by a recipient to update a network allocation vector (NAV).

[0070] The RA field is the address of the STA that is intended to receive the incoming transmission from the transmitting station. The TA field is the address of the STA transmitting trigger frame 400 if trigger frame 400 is addressed to STAs that belong to a single BSS. The TA field is the transmitted BSSID if the trigger frame 400 is addressed to STAs from at least two different BSSs of the multiple BSSID set.

[0071] The common info field may have a format as illustrated by common info field 600 described further below. The common info field specifies a trigger frame type of trigger frame 400, a transmit power of trigger frame 400 in dBm, and several key parameters of a TB PPDU that is transmitted by a STA in response to trigger frame 400. The trigger frame type of a trigger frame used by an AP to receive QoS data using UL MU operation is referred to as a basic trigger frame.

[0072] The User List Info field contains a User Info field per STA addressed in trigger frame 400. The per STA User Info field includes, among others, an AID subfield, an RU Allocation subfield, a Spatial Stream (SS) Allocation subfield, an MCS subfield to be used by a STA in a TB PPDU transmitted in response to trigger frame 400, and a Trigger Dependent User Info subfield. The Trigger Dependent User Info subfield can be used by an AP to specify a preferred access category (AC) per STA. The preferred AC sets the minimum priority AC traffic that can be sent by a participating STA. The AP determines the list of participating STAs, along with the BW, MCS, RU allocation, SS allocation, Tx power, preferred AC, and maximum duration of the TB PPDU per participating STA.

[0073] The Padding field is optionally present in trigger frame 400 to extend the frame length to give recipient STAs enough time to prepare a response for transmission one SIFS (short interframe spacing) after the frame is received. The Padding field, if present, is at least two octets in length and is set to all 1s.

[0074] The FCS field is used by a STA to validate a received frame and to interpret certain fields from the MAC headers of a frame.

[0075] FIG.5 illustrates an example multi-user request to send (MU-RTS) trigger frame 500. MU-RTS trigger frame 500 may be used by an AP to solicit simultaneous CTS frames from multiple STAs to transmit a downlink (DL) MU PPDU to the multiple STAs. As shown in FIG. 5, MU-RTS trigger frame 500 may comprise a frame control field, a duration field, an RA field, a TA field, a common info field, one or more user info fields, a padding field, and an FCS field. The frame control, TA, RA, padding, and FCS fields may be similar to thePCT / US25 / 48151 26 September 2025 (26.09.2025)Docket No.: 24-3044 PCT corresponding fields of trigger frame 400 described above. The common info field may have a format as illustrated by common info field 600 described further below. The duration field may be set to the time, in microseconds, required to transmit the DL MU PPDU, plus the time required to transmit one CTS frame, one ACK frame (if required), and three SIPS periods.

[0076] The one or more user info fields correspond respectively to the one or more STAs solicited by U- RTS trigger frame 500. As shown in FIG. 5, a user info field may comprise an AID12 subfield, an RU allocation subfield, reserved bits, and a PS 160 subfield. The AID12 subfield comprises an association identifier of the STA to which the user info field is addressed. The RU allocation subfield indicates a channel on which the solicited STA is to transmit the CTS frame. In an example, this may include a primary 20 MHz channel, a primary 40 MHz, a primary 80 MHz channel, a primary 160 MHz, an 80+80 Mhz channel, or a 320 MHz channel.

[0077] FIG. 6 illustrates an example Common Info field 600. Common Info field 600 may be an embodiment of the Common Info field of trigger frame 400 or MU-RTS trigger frame 500, for example. As shown in FIG. 6, Common Info field 600 may include a Trigger Type subfield, a UL Length subfield, a More TF subfield, a CS required subfield, a UL BW subfield, a Gl and HE / EHT-LTF Type / Triggered TXS Mode subfield, a first Reserved subfield, a Number of HE / EHT-LTF Symbols subfield, a second Reserved subfield, an LDPC Extra Symbol Segment subfield, an AP Tx Power subfield, a Pre-FEC Padding Factor subfield, a PE Disambiguity subfield, an UL Spatial Reuse subfield, a third Reserved subfield, an HE / EHT P160 subfield, a Special User Info Field Flag subfield, an EHT Reserved subfield, a fourth Reserved subfield, and a Trigger Dependent Common Info subfield. The Trigger Type subfield, UL Length subfield, More TF subfield, CS required subfield, UL BW subfield, Gl and HE-LTF Type / Triggered TXS Mode subfield, first Reserved subfield, Number of HE / EHT-LTF Symbols subfield, second Reserved subfield, LDPC Extra Symbol Segment subfield, AP Tx Power subfield, Pre-FEC Padding Factor subfield, PE Disambiguity subfield, UL Spatial Reuse subfield, third Reserved subfield, HE / EHT P160 subfield, Special User Info Field Flag subfield, EHT Reserved subfield, fourth Reserved subfield, and Trigger Dependent Common Info subfield may have the same content and interpretation as corresponding subfields of an EHT variant Common Info field defined in the IEEE 802.11 be draft amendment ("IEEE P802.11 be / D3.1 , March 2023’’).

[0078] FIG. 7 illustrates an example 700 of a Request-to-Send (RTS) / Clear-to-Send (CTS) procedure. Example 700 may be an example according to the RTS / CTS procedure as defined in section 10.3.2.9 of the IEEE 802.11 standard draft “IEEE P802.11-REVme™ / D3.0, April 2023.” As shown in FIG. 7, example 700 may include STAs 702 and 704. Other STAs of the same BSS may also be within communication range of STAs 702 and 704.

[0079] In an example, STA 702 may transmit an RTS frame 706 to STA 704. STA 702 may transmit RTS frame 706 to protect from hidden STA(s) the transmission of a data frame 710 that STA 702 intends to transmit. RTS frame 706 may include a Duration / I D field. The Duration / ID field may be set to the time, inPCT / US25 / 48151 26 September 2025 (26.09.2025)Docket No.: 24-3044 PCT microseconds, required to transmit data frame 710, plus one CTS frame, plus one ACK frame (if required), plus three SIPS (Short Interframe Spacing) periods.

[0080] In an example, STA 704 may respond to RTS frame 706 by transmitting a CTS frame 708 to STA 702. CTS frame 708 may be transmitted one SIFS period after RTS frame 706. STA 704 may respond to RTS frame 706 when RTS frame 706 is addressed to STA 704 and after considering the NAV, unless the NAV was set by a frame originating from STA 702. STA 704 may respond to the RTS frame 706 when RTS frame 706 is addressed to STA 704 and if the NAV indicates idle. For a non-S1G STA, the NAV indicates idle when the NAV count is 0 or when the NAV count is non-zero but a nonbandwidth signaling TA obtained from a TA field of RTS frame 706 matches a saved TXOP holder address. For an S1GSTA, the NAV indicates idle when both the NAV and RID (response indication deferral) counters are 0 or when either the NAV or RID counter is non-zero but the TA field of RTS frame 706 matches the saved TXOP holder address.

[0081] STA 704 may set an RA field of CTS frame 708 to a nonbandwidth signaling TA obtained from the TA field of RTS frame 706. STA 704 may set a Duration field of CTS frame 708 based on the Duration / ID field of RTS frame 706, namely as equal to the value of the Duration / ID field of RTS frame 706, adjusted by subtracting the time required to transmit CTS frame 708 and one SIFS period.

[0082] Upon receiving CTS frame 708, STA 702 may wait one SIFS period before transmitting data frame 710. STA 704 may transmit an ACK frame 712 in response to data frame 710. STA 704 may transmit ACK frame 712 one SIFS after receiving data frame 710.

[0083] As shown in example 700, other STAs within communication range of STAs 702 and 704, and belonging to the same BSS, may set their NAVs according to RTS frame 706 and / or CTS frame 708. For example, a STA receiving RTS frame 706 may set its NAV based on the Duration / ID field of RTS frame 706. Another STA receiving CTS frame 708 may set its NAV based on the Duration field of CTS frame 708. As such, the other STAs may not access the channel using EDCA until the end of transmission of ACK frame 712.

[0084] FIG. 8 is an example 800 that illustrates a multi-user Request-to-Send (MU-RTS) / Clear-to-Send (CTS) procedure. Example 800 may be an example according to the MU-RTS / CTS procedure as defined in section 26.2.6 of the IEEE 802.11 standard draft. As shown in FIG. 8, example 800 may include an AP 802 and STAs 804 and 806. STAs 804 and 806 may be associated with AP 802. For the purpose of illustration, example 800 also illustrates STAs of an overlapping basic service set (OBSS) relative to the BSS of AP 802 (OBSS STAs). The OBSS STAs, as shown in FIG. 8, may be hidden from AP 802 (outside of the communication range of AP 802) or exposed to AP 802 (within the communication range of AP 802).

[0085] In example 800, AP 802 wishes to transmit a downlink (DL) multi-user (MU) PPDU 814 to STAs 804 and 806. DL MU PPDU 814 may comprise data for each of STAs 804 and 806. DL MU PPDU 814 may occupy a plurality of channels (e.g ., 20 MHz channels). Each channel of the plurality of channels may carry the data for a respective STA (e.g., STA 804, STA 806) served by DL MU PPDU 814.PCT / US25 / 48151 26 September 2025 (26.09.2025)Docket No.: 24-3044 PCT

[0086] As shown in FIG. 8, to protect the transmission of DL MU PPDU 814 to STAs 804 and 806 from interference by OBSS STAs hidden from AP 802, AP 802 may use the MU-RTS / CTS procedure to initiate a TXOP and to protect the TXOP frame exchange sequence. AP 802 may initiate the TXOP by transmitting an MU-RTS trigger frame 808 that solicits simultaneous CTS frame transmissions from STAs 804 and 806.

[0087] MU-RTS trigger frame 808 may have a format as illustrated by MU-RTS trigger frame 500 illustrated in FIG. 5. As such, MU-RTS trigger frame 808 may comprise a frame control field, a duration field, an RA field, a TA field, a common info field, one or more user info fields, a padding field, and an FCS field. The duration field may be set to the time, in microseconds, required to transmit DL MU PPDU 814, plus the time required to transmit one CTS frame, one ACK frame (if required), and three SIFS periods.

[0088] The one or more user info fields correspond respectively to the one or more STAs solicited by the MU-RTS trigger frame. In example 800, MU-RTS trigger frame 808 may comprise a user info field for each of STAs 804 and 806 indicating that a CTS frame is solicited from each of STAs 804 and 806. As shown in FIG. 8, a user info field may comprise an AID12 subfield, an RU allocation subfield, reserved bits, and a PS 160 subfield. The AID12 subfield comprises an association identifier of the STA to which the user info field is addressed. The RU allocation subfield indicates a channel on which the solicited STA is to transmit the CTS frame. In an example, this may include a primary 20 MHz channel, a primary 40 MHz, a primary 80 MHz channel, a primary 160 MHz, an 80+80 Mhz channel, or a 320 MHz channel.

[0089] AP 802 may send MU-RTS trigger frame 808 in a PPDU that occupies one or more channels (e.g ., 20 MHz channels). In an example, for each channel occupied by the PPDU that carries MU-RTS trigger frame 808, AP 802 may request at least one non-AP STA to send a CTS frame that occupies that channel. In an example, AP 802 may not request that a non-AP STA send a CTS frame that occupies a channel that is not occupied by the PPDU carrying MU-RTS trigger frame 808.

[0090] After transmitting MU-RTS trigger frame 808, AP 802 may wait for a CTSTimeout interval of aSIFSTime + aSlotTime + aRxPHYStartDelay that begins when a MAC layer of AP 802 receives a PHYTXEND.confirm primitive for transmitted MU-RTS trigger frame 808. If the MAC layer does not receive a PHY-RXEARLYSIG.indication or a PHY-RXSTART.indication primitive during the CTSTimeout interval, AP 802 may conclude that the transmission of MU-RTS trigger frame 808 has failed, and, if MU-RTS trigger frame 808 initiated a TXOP, AP 802 may invoke its backoff procedure. If the MAC layer receives a PHY- RXEARLYSIG.indication or a PHY-RXSTART.indication primitive during the CTSTimeout interval, then the MAC layer may wait for the corresponding PHY-RXEND. indication primitive to determine whether transmission of MU-RTS trigger frame 808 was successful. The receipt of a CTS frame from any non-AP STA addressed by MU-RTS trigger frame 808 before the PHY-RXEND. indication primitive shall be interpreted as the successful transmission of MU-RTS trigger frame 808, permitting the frame exchange sequence to continue. The receipt of any other type of frame shall be interpreted as a failure of the transmission of MU-RTS trigger frame 808. AP 802 may process the received frame and, if MU-RTS triggerPCT / US25 / 48151 26 September 2025 (26.09.2025)Docket No.: 24-3044 PCT frame 808 initiated a TXOP, AP 802 shall invoke its backoff procedure at the PHY-RXEND. indication primitive.

[0091] In example 800, on receiving MU-RTS trigger frame 808, STAs 804 and 806 respond by transmitting respectively CTS frames 810 and 812 to AP 802. In an example, STAs 804 and 806 begin the transmission of CTS frames 810 and 812, respectively, at the SIPS time boundary after an end of a received PPDU comprising Mll-RTS trigger frame 808. In an example, STA 804 (or STA 806) responds to MU-RTS trigger frame 808 with a CTS frame when the following conditions are met: MU-RTS trigger frame 808 comprises a user info field addressed to the STA (the AID12 subfield of the user info field is equal to the 12 LSBs of the AID of the STA) and MU-RTS trigger frame 808 is sent by an AP with which the STA is associated; and the UL MU CS condition indicates that the medium is idle as described in section 26.5.2.5 (UL MU CS mechanism) of the IEEE 802.11 standard ("IEEE P802.11 -REVme™ / D3.0, April 2023"). Otherwise, if one of the conditions is not met, STA 804 (or STA 806) does not send a CTS frame to AP 802.

[0092] In an example, STAs 804 and 806 may set an RA field of respectively CTS frames 810 and 812 to a TA obtained from the TA field of MU-RTS trigger frame 808. In an example, STAs 804 and 806 may set a duration field of respectively CTS frames 810 and 812 based on the duration field of MU-RTS trigger frame 808, namely as equal to the value of the duration field of MU-RTS trigger frame 808, adjusted by subtracting the time required to transmit respectively CTS frames 810 and 812 and one SIFS period.

[0093] OBSS STAs exposed to AP 802 may receive MU-RTS trigger frame 808 due to being within the communication range of AP 802. In an example, as shown in FIG. 8, on receiving MU-RTS trigger frame 808, OBSS STAs exposed to AP 802 set their respective NAVs based on the duration field of MU-RTS trigger frame 808. As such, the OBSS STAs exposed to AP 802 may not access the wireless medium for the duration of the TXOP initiated by AP 802.

[0094] OBSS STAs hidden from AP 802 do not receive MU-RTS trigger frame 808 due to being outside the communication range of AP 802. However, in an example, as shown in FIG. 8, some of the OBSS STAs hidden from AP 802 may receive CTS frame 810 and / or CTS frame 812 and may set their respective NAVs based on the duration field of CTS frame 810 and / or CTS frame 812. As such, some of the OBSS STAs hidden from AP 802 may also not access the wireless medium for the duration of the TXOP initiated by AP 802.

[0095] On receiving CTS frame 810 and / or CTS frame 812, AP 802 may wait one SIFS period before transmitting DL MU PPDU 814. On receiving DL MU PPDU 814, STAs 804 and 806 may respond by transmitting respective BlockAck (BA) frames 816 and 818 to AP 802.

[0096] It is envisioned in future IEEE 802.11 standards that a STA (AP STA or non-AP STA) may access a non-primary channel to communicate with another STA. Such operation may be referred to as non-primary channel access (NPCA) operation. Specifically, in addition to a default primary channel (which is used by all STAs in the BSS), the STA may have one or more secondary channels considered as NPCA primaryPCT / US25 / 48151 26 September 2025 (26.09.2025)Docket No.: 24-3044 PCT channels. The STA may transmit or receive on a channel that includes an NPCA primary channel but that does not necessarily include the primary channel (e.g., when the primary channel is unavailable). The STA may maintain a NAV for an NPCA primary channel independent of the NAV associated with the primary channel.

[0097] FIG. 9 shows an example that illustrates non-primary channel access (NPCA) operation. For the purpose of illustration, NPCA operation is contrasted with single primary channel (non-NPCA STA) operation. As shown in FIG. 9, the STA may be capable of operating over a plurality of channels. According to non- NPCA operation, the plurality of channels may include a primary channel (PCH), a first secondary channel (SCH1), a second secondary channel (SCH2), and a third secondary channel (SCH2). According to NPCA operation, the same channels may include a primary channel (PCH), a first secondary channel (SCH1), an NPCA primary channel (NPCA PCH), and a second secondary channel (SCH2). It is noted that the position of the NPCA primary channel may or may not be as shown in the example of FIG. 9. For example, the NPCA primary channel may correspond to SCH1.

[0098] In an implementation, as shown in FIG. 10, in non-NPCA operation, a virtual carrier sense (CS) function (e.g., NAV) may be associated with only the PCH. Secondary channels may have only a physical CS function (e.g., energy detection) associated with them, which may be performed only when contending for transmission on the PCH. As such, as shown in FIG. 9, the STA may only transmit on a channel that includes the PCH (e.g., PCH, PCH+SCH1, PCH+SCH1+SCH2, PCH+SCH1+SCH2+SCH3) and only when the NAV associated with the PCH is zero (and the physical CS function indicates “channel idle” for all channels being used).

[0099] In contrast, as shown in FIG. 10, in NPCA operation, a virtual CS function (e.g., NAV) may be associated with multiple channels (e.g., PCH and NPCA PCH). As such, as shown in FIG. 9, the STA may transmit on channels that do not include the PCH but that include the NPCA PCH (e.g., NPCA PCH, NPCA PCH+SCH1, NPCA PCH+SCH2) if the NAV associated with the NPCA PCH is zero (and the physical CS indicates “channel idle" for all channels being used). In an implementation, the STA may also transmit on channels that do not include the PCH but that include the NPCA PCH (e.g., NPCA PCH, NPCA PCH+SCH1 , NPCA PCH+SCH2) if the STA detects that the NPCA PCH is idle using physical CS for at least a medium synchronization duration.

[0100] In implementations, the STA may perform physical and / or virtual CS functions (herein referred to as CS or CCA) on multiple channels (e.g., PCH and NPCA PCH). If the PCH is busy (non-zero NAV or CCA indicates “channel busy”), the STA may use the NPCA PCH for transmission if the NPCA PCH is idle (zero NAV and CCA indicates “channel idle”).

[0101] In an implementation, the STA may perform CS in parallel on multiple channels, including the PCH and the NPCA PCH. Such a STA is referred to herein as a concurrent CCA NPCA STA (such a STA may also be referred to as a concurrent CCA multiple primary channel (MPC) STA or a Type 1 STA). Because ofPCT / US25 / 48151 26 September 2025 (26.09.2025)Docket No.: 24-3044 PCT its concurrent CCA capability, a concurrent CCA NPCA STA is capable of medium synchronization simultaneously on multiple channels (e.g., PCH and NPCA PCH). Medium synchronization on a channel (e.g., PCH or NPCA PCH) may be performed by detecting a frame that includes NAV information or by listening to the channel for at least a medium synchronization duration and finding the channel idle throughout the medium synchronization duration. An NPCA STA that does not support this capability may perform CS on a single channel at a time. In an implementation, an NPCA STA may perform CS on the PCH by default, and when the PCH is found busy, the STA may perform CS on the NPCA PCH. Such a STA is referred to herein as a non-concurrent CCA NPCA STA (such a STA may also be referred to as a non-concurrent CCA MPC STA or a Type 2 STA). In contrast to the concurrent CCA NPCA STA, a non-concurrent CCA NPCA STA may only synchronize to the NPCA PCH after the PCH is found busy. Hence, it may need to listen to the channel for at least a medium synchronization duration (if it does not receive any frame that includes NAV information) before it is able to transmit.

[0102] In an implementation, a STA that supports NPCA operation may be called an NPCA STA. An AP that supports NPCA operation may be called an NPCA AP. A non-AP NPCA STA may set an NPCA Supported field of a UHR MAC Capabilities Information field of a LIHR Capabilities element to 1. In an implementation, a non-AP NPCA STA does not enable the NPCA mode unless the non-AP NPCA STA is associated with an NPCA AP that has enabled NPCA operation.

[0103] In an implementation, an NPCA AP that has an operating bandwidth less than 80 MHz does not enable NPCA operation. In an implementation, an AP of a multiple BSSID set that enables NPCA operation may indicate the same NPCA primary channel, same NPCA minimum duration, same NPCA switching delay, and same NPCA switch back delay as all of the other APs of the same multiple BSSID set that have enabled NPCA operation. In an implementation, an AP of a co-hosted BSS that enables NPCA operation may indicate the same NPCA primary channel, same NPCA minimum duration, same NPCA switching delay, and same NPCA switch back delay as all of the other APs of the same co-hosted BSSs that have enabled NPCA operation.

[0104] In an implementation, an NPCA AP that has enabled NPCA operation may set to 1 the NPCA Enabled field in the UHR Operation element of the (Re)Association Response, UHR Link Reconfiguration Notify, Beacon and Probe Response frames that it transmits.

[0105] In an implementation, an NPCA AP with a value (e.g., dotHHEPSROption Implemented) set to true may set the TXVECTOR parameter SPATIAL_REUSE to PSR_DISALLOW for PPDUs that it transmits, and may set the PSR Disallowed subfield in the SR Control field of the Spatial Reuse Parameter Set element to 1 in Management frames it transmits before enabling NPCA operation in its BSS and while NPCA operation remains enabled.PCT / US25 / 48151 26 September 2025 (26.09.2025)Docket No.: 24-3044 PCT

[0106] In an implementation, an AP may enable a PHY Header-based (PHYLEN) NPCA operation by setting a MAC Header-based (MOPLEN) NPCA field to 0 and may enable both PHYLEN NPCA and MOPLEN NPCA operation by setting the MOPLEN NPCA field to 1.

[0107] In an implementation, an NPCA AP may advertise an NPCA Disabled Subchannel Bitmap field in the NPCA Operation Parameters field. The NPCA Disabled Subchannel Bitmap field may indicate the subchannels that are punctured when an NPCA STA operates on the NPCA primary channel:If an NPCA Disabled Subchannel Bitmap field is present, then the NPCA Disabled Subchannel Bitmap Field Present bit may be set to 1, otherwise the NPCA Disabled Subchannel Bitmap Field Present field may be set to 0.The NPCA Disabled Subchannel Bitmap field value may satisfy the following requirements:• The puncturing pattern indicated by the value of the NPCA Disabled Subchannel Bitmap field is a valid non-OFDM A puncturing pattern.• A 20 MHz subchannel indicated as punctured in the Disabled Subchannel Bitmap field of an EHT Operation element (if any) is also indicated as punctured in the NPCA Disabled Subchannel Bitmap field.An NPCA AP may indicate one or more 20 MHz subchannels as punctured in the NPCA Disabled Subchannel Bitmap field of the EHT Operation Element for the purpose of maximizing the BW of the NPCA operating channel.An NPCA AP may indicate one or more 20 MHz subchannels as punctured in the NPCA Disabled Subchannel Bitmap field of the EHT Operation Element for the purpose of creating a gap between the PPDU that initiated the NPCA switch and the NPCA operating channel.If no NPCA Disabled Subchannel Bitmap field is present in the NPCA Operation Parameters field transmitted by the AP that the STA is associated with, then the subchannels may be punctured during NPCA operation.

[0108] In an implementation, an NPCA AP may indicate a value in the NPCA Primary Channel field, of transmitted NPCA Operation Parameters fields, that corresponds to a channel that is located within the secondary 40 MHz of the BSS operating channel if the BSS is an 80 MHz BSS, that corresponds to a channel that is located within the secondary 80 MHz of the BSS operating channel if the BSS is a 160 MHz BSS, and that corresponds to a channel that is located within the secondary 160 MHz of the BSS operating channel if the BSS is a 320 MHz BSS.

[0109] In an implementation, a non-AP NPCA STA may indicate an NPCA switching delay and an NPCA switch back delay, respectively, in the NPCA Switching Delay field and NPCA Switch Back Delay fields of the CMP Request frames.PCT / US25 / 48151 26 September 2025 (26.09.2025)Docket No.: 24-3044 PCT

[0110] In an implementation, when a non-AP STA that supports NPCA mode (re)associates with an AP, the NPCA mode may be disabled by default for the non-AP STA. In the UHR OMP request sent to enable or update the parameters of NPCA mode for the non-AP STA, a non-AP STA may include the following in the Mode Parameters field of the Mode Tuple field:NPCA switching delay,NPCA switch back delay.

[0111] In an implementation, for a non-AP STA to enable NPCA mode, the associated AP must support NPCA and must have NPCA enabled for the BSS.

[0112] In an implementation, if an NPCA AP that has enabled NPCA operation advertises MU EDCA parameters in the Beacon frames that it transmits, a MU EDCA protocol may apply jointly on both BSS primary channel and NPCA primary channel for a non-AP NPCA STA. In an implementation, an NPCA STA may maintain a single MU EDCA timer that is shared across the BSS primary channel and the NPCA primary channel, transition from using EDCA parameters to using MU EDCA parameters (and vice-versa) at the same time on both the BSS primary channel and the NPCA primary channel based on certain conditions that occur on either the BSS primary channel or the NPCA primary channel, and when the STA is operating on the NPCA primary channel, use the same MU EDCA parameters as are used on the BSS primary channel except that Al FSN [AC] may be set to 0 for all ACs. When the STA switches back to the BSS primary channel, it may revert to using the Al PS N [AC] values from the dot11 MUEDCATable.

[0113] In an implementation, an NPCA STA does not switch to the NPCA primary channel for NPCA operation if NPCA mode has not been enabled by its associated AP.

[0114] In an implementation, an NPCA STA may switch to the NPCA primary channel for NPCA operation if the NPCA mode has been enabled for the BSS of which it is a member and either condition 1 ) or 2) is met: 1) the STA received a PPDU and / or received a PHY-RXSTART.indication primitive for an HE / EHT / UHR PPDU on the BSS primary channel and all of the following conditions are true: a) Condition 2) is not true. b) The PPDU is classified by the STA as in inter-BSS PPDU. c) At least one of the following conditions is true: i) The value of the MAC variable NPCA_PPDU_REM_DUR derived from the received PPDU is greater than the value indicated in the most recently received or transmitted NPCA Minimum Duration Threshold field corresponding to the BSS of which the STA is a member. ii) If the NPCA AP corresponding to the BSS of which the STA is a member has enabled MOPLEN NPCA in addition to PHYLEN NPCA and the value of the MAC variable NPCA_PHY_TXOP_REM_DUR derived from the received PPDU is greater than the value indicated in the most recently received orPCT / US25 / 48151 26 September 2025 (26.09.2025)Docket No.: 24-3044 PCT transmitted NPCA Minimum Duration Threshold field corresponding to the BSS of which the STA is a member. d) The bandwidth of the PPDU is determined by the STA to be 20, 40, 80 or 160 MHz, based on the Bandwidth field in the PHY preamble of the PPDU and the channel occupied by the PPDU does not overlap with the NPCA primary channel, e) If the STA maintains an intra-BSS NAV, it is zero.2) All of the following conditions are true: a) A sequence of three PPDUs, separated by aSIFSTime, is identified on the BSS primary channel, comprising an initial Control frame, an initial response frame, and a third PPDU following the initial response frame. b) The STA received at least the first PPDU containing the initial Control frame and the PHY- RXSTART.indication and / or the PHY-RXEARLYSIG.indication of the third PPDU. c) An indication that a valid TXOP was obtained on the BSS primary channel, as verified by the receipt of a PHY-RXEARLYSIG.indication or PHYRXSTART. indication primitive corresponding to the third PPDU that occurs during a time window that: i) begins at aSIFSTime + ICR_Timeout after the MAC receives a PHY-RXEND. indication primitive corresponding to the first PPDU, where ICR_Timeout is equal to:(1) The length (in usee) of the expected CTS if the initial Control frame is an RTS or an MU-RTS Trigger frame,(2) the value of RXTIME calculated using Equation (27-147) with the value of LENGTH replaced by the value from the UL Length field of the Common Info field, if the initial Control frame is a BSRP Trigger frame or a BSRP NTB Trigger frame. ii) has a duration that is equal to NPCA_START_TIMEOUT which is aSIFSTime + (2 x aSlotTime) + aRxPHYStartDelay. d) At least one of the three PPDUs in the sequence of PPDUs is classified by the STA as an inter-BSS PPDU. e) At least one of the following conditions is true: i) The NPCA AP corresponding to the BSS of which the STA is a member has enabled PHYLEN NPCA only and the value of the MAC variable NPCA_PPDU_REM_DUR derived from the received third PPDU of the sequence of PPDUs is greater than the value indicated in the most recently received or transmitted NPCA Minimum Duration Threshold field corresponding to its BSS, ii) If the NPCA AP corresponding to the BSS of which the STA is a member has enabled MOPLEN NPCA in addition to PHYLEN NPCA and the value of the MAC variable NPCA_CFRAME_TXOP_REM_DURPCT / US25 / 48151 26 September 2025 (26.09.2025)Docket No.: 24-3044 PCT derived from the received first PPDU (containing the initial Control frame of the control frame exchange) of the sequence of PPDUs is greater than the value indicated in the most recently received or transmitted NPCA Minimum Duration Threshold field corresponding to its associated BSS. f) The bandwidth of the third PPDU is determined by the STA to be 20, 40, 80, 160 or 320 MHz based on the Bandwidth field in the PHY preamble of the PPDU not overlap with the NPCA primary channel and the channel occupied by the PPDU does not overlap with the NPCA primary channel. g) If the STA maintains an intra-BSS NAV, it is zero at the time of the receipt of the PHYRXSTART.indication and / or the PHY-RXEARLYSIG.indication of the first PPDU.

[0115] In an implementation, when a PHY-CCA.indication(BUSY) primitive corresponding to the start of the reception of a PPDU is indicated at an NPCA STA while operating on the BSS primary channel, the values of the MAC variables NPCA_PPDU_REM_DUR, NPCA_PHY_TXOP_REM_DUR and NPCA_TIMER are all set to 0. When a PH Y-CCA. ind ication(BUSY) corresponding to the start of the reception of a PPDU containing an initial Control frame is indicated at an NPCA STA while operating on the BSS primary channel, the MAC variable NPCA_CFRAME_TXOP_REM_DUR is set to 0.

[0116] In an implementation, the MAC variable NPCA_PPDU_REM_DUR derived from a received PPDU is equal to the value in usee, of the remaining duration of the received PPDU, determined by the MAC at the time of the receipt of the PHY-RXSTART.indication primitive associated with the received PPDU, by subtracting the time elapsed between the reception of the PHY-CCA.indication(BUSY) and PHYRXSTART.indication primitives associated with the received PPDU from the value of RXTIME of the received PPDU.

[0117] In an implementation, the MAC variable NPCA_PHY_TXOP_REM_DUR derived from a received PPDU is:Set to 0, if the RXVECTOR parameter TXOP.DURATION is UNSPECIFIED, or if the NPCA AP corresponding to the BSS of which the STA is a member has not enabled MOPLEN NPCA.Otherwise, it is equal to the value in usee, of the remaining duration of the PPDU, determined by the MAC at the time of the receipt of the PHY-RXSTART.indication primitive associated with the received PPDU, by subtracting the time elapsed between the reception of the PHY-CCA.indication(BUSY) and PHY- RXSTART.indication primitives associated with the received PPDU from the value of RXTIME corresponding to the received PPDU, plus the value of the TXOP_DURATION parameter of the RXVECTOR of the PPDU.

[0118] In an implementation, the MAC variable NPCA_CFRAME_TXOP_REM_DUR derived from a received PPDU is:Set to 0, if the NPCA AP corresponding to the BSS of which the STA is a member has not enabled MOPLEN NPCA.PCT / US25 / 48151 26 September 2025 (26.09.2025)Docket No.: 24-3044 PCTOtherwise, it is set to the value in the Duration / I D field of the initial Control frame in the received PPDU at the receipt of the PHY-RXEND. indication primitive of the PPDU that contained the frame. The value of NPCA_CFRAME_TXOP_REM_DUR is reduced by the amount of time elapsed between the PHY- RXEND. indication primitive of the initial Control frame from which the value of NPCA_CFRAME_TXOP_REM_DUR was determined and the PHY-RXSTART. indication primitive of the third PPDU of the frame exchange sequence identified in condition 2) above at the time of the receipt of the PHY- RXSTART.indication primitive of the third PPDU.

[0119] In an implementation, when an NPCA STA switches to the NPCA primary channel for NPCA operation, then the following rules apply:1) If the STA switches from the BSS primary channel to the NPCA primary channel based on meeting condition 1) described above, the STA initiates the switch at the NPCA HE switch time and shall be ready to transmit and receive frames (subject to its capabilities and operating mode) on the NPCA primary channel no later than the value of its most recently indicated NPCA switching delay after the NPCA HE switch time. The NPCA HE switch time is the point in time immediately after the reception of the HE-SIG-A / U-SIG field of the received PPDU from condition 1) above.2) If the STA switches from the BSS primary channel to the NPCA primary channel based on meeting condition 2) described above, the STA initiates the switch at the NPCA NHT switch time and shall be ready to transmit and receive frames addressed to it (subject to its capabilities and operating mode) on the NPCA primary channel no later than the value of its most recently indicated NPCA switching delay after the NPCA NHT switch time. The NPCA NHT switch time is equal to the point in time that is 3 x TSYM after the reception of the L-SIG field of the third PPDU of the received sequence of PPDUs from condition 2) above.3) The STA uses the same EDCA parameter set and EPCS EDCA parameter set values for operation on the NPCA primary channel as it uses on the BSS primary channel.4) At each NPCA HE switch time or NPCA NHT switch time, as appropriate, if the STA is an AP or if the STA is a non-AP STA and transmission of frames that are not a response to a Trigger frame is not disabled by the MU EDCA protocol, the STA may initiate a TXOP on the NPCA primary channel with the following exceptions: a) Each time that the STA switches to the NPCA primary channel, the STA does:I) If condition 1) is met, set NPCA_CFRAME_TXOP_REM_DUR to 0, set NPCA_TIMER to the largest non-zero value of the variables NPCA_PPDU_REM_DUR, NPCA_PHY_TXOP_REM_DUR and NPCA_CFRAME_TXOP_REM_DUR, minus the switch back delay that the STA indicated in the most recently transmitted NPCA Operation Parameters field.II) Store the existing values of the variables QSRCjAC], CW[AC] and the backoff counter for each EDCAF.PCT / US25 / 48151 26 September 2025 (26.09.2025)Docket No.: 24-3044 PCT iii) Set QSRC[AC] for each AC to the value of the Initial NPCA QSRC field of the NPCA Operation Parameters received from its associated NPCA AP. iv) initialize variables CW[AC] to 2lnit-QSRc_NPCA x CWmin[AC] + 1) - 1. v) invoke the backoff procedure even if the medium for the NPCA primary channel is not busy. vi) initiate countdown of the MAC variable NPCA_TIMER in units of 1 usee.5) A first STA does not initiate a transmission on the NPCA primary channel to a second STA until theNPCA switching delay time of the second STA has elapsed since the NPCA HE switch time at the first STA if the first STA is switching due to condition 1) above or since the NPCA NHT switch time at the first STA if the first STA is switching due to condition 2) above6) The STA begins all frame exchanges on the NPCA primary channel with an initial control frame (ICF) using non-HT PPDU or non-HT duplicate PPDU format using a rate of 6 Mb / s, 12 Mb / s, or 24 Mb / s. a) For TXOPs initiated by an AP, the ICF is a BSRP Trigger frame or an MU-RTS Trigger frame except when at least one of the target non-AP STA(s) is operating in the DUO mode, in which case, the ICF may be a BSRP Trigger frame or a BSRP NTB Trigger frame but not an MU-RTS. In addition, the ICF conforms to the rules for Dynamic Unavailability Operation (DUO) mode if at least one of the target non-AP STA(s) is operating in DUO mode, to the rules for Enhanced multi-link single-radio (EMLSR) operation if at least one of the target non-AP STA(s) is affiliated with a non-AP MLD that is operating in EMLSR mode, and to the rules for Dynamic power save (DPS) operation if at least one of the target non-AP STA(s) :s operating in DPS mode. b) For TXOPs initiated by a non-AP STA, the initial control frame is a BSRP NTB Trigger frame, except that if the non-AP STA is operating in the Dynamic Unavailability Operation mode (DUO), then the ICF conforms to the DUO mode rules.7) An NPCA AP that transmits a T rigger frame on the NPCA primary channel indicates RU index values that use the NPCA primary channel as the reference primary channel.8) An NPCA STA that transmits a Trigger frame on the NPCA primary channel sets the NPCA Primary Indication field to 1 in the Special User Info field, otherwise, this field is set to 0.9) The 20 MHz channels occupied by PPDUs transmitted by the STA shall meet all of the following conditions: a) include at least the NPCA primary channel. b) all be within the BSS bandwidth. c) not include any of the channels occupied by either the PPDU mentioned in condition 1) or by the third PPDU mentioned in condition 2), whichever caused the STA to switch from the BSS primary channel to the NPCA primary channel.PCT / US25 / 48151 26 September 2025 (26.09.2025)Docket No.: 24-3044 PCT d) not include channels that are indicated as punctured in the Disabled Subchannel Bitmap field in the EHT Operation element or in the NPCA Disabled Subchannel Bitmap field in the UHR Operation element.10) UHR ELR PPDUs, HE ER SU PPDUs, EHT MCS14 / 15 shall not be transmitted on the NPCA primary channel.11) Dynamic Subband Operation shall not be used on the NPCA primary channel.12) If TBTT for the BSS occurs while an NPCA AP is operating on the NPCA primary channel, the scheduling of the transmission of the Beacon frame and following group addressed frames shall be deferred until immediately after the AP switches back to the BSS primary channel.

[0120] In an example, an AP and associated STAs are not required to switch back to the BSS primary channel at TBTT. The group addressed frames may be buffered and delivered immediately following the next DTIM Beacon, unless explicitly specified otherwise. Further, in an example, exponential backoff may apply on the NPCA primary channel when there are failed transmissions.

[0121] In an implementation, an NPCA STA shall switch back to the BSS primary channel when the NPCA_TIMER expires. In an implementation, when the STA switches back to the BSS primary channel, it may:1) replace the current values of the variables QSRC[AC], CW[AC] and the backoff counter for each EDCAF with the values that it stored when it switched to the NPCA primary channel.2) resume the backoff procedure.

[0122] FIG. 11 shows an example 1100 that illustrates NPCA operation. As shown in FIG. 11, example 1100 includes an AP and a STA associated with the AP. The AP and the STA may both support NPCA operation and may operate over a plurality of channels, including a primary channel (PCH), an NPCA primary channel (NPCA PCH), a first secondary channel (SCH1), and a second secondary channel (SCH2).

[0123] Example 1100 may begin with the AP transmitting a frame 1102 on the PCH. Frame 1102 may indicate a medium synchronization duration for the NPCA PCH. The medium synchronization duration of a channel indicates a minimum duration that a STA must listen to the channel before the STA is able to transmit on the channel (if the STA does not receive via the channel before the end of the medium synchronization duration a frame that indicates NAV information). Frame 1102 may be a management frame, such as a beacon frame, for example.

[0124] Subsequently, while the AP and STA operate on the PCH, transmission of a frame 1104 from an OBSS may begin on the PCH. The AP and the STA may detect frame 1104 on the PCH. In an implementation, the AP and STA may be configured to set a NAV associated with the PCH based on receiving frame 1104 on the PCH. Frame 1104 may indicate a transmission on the PCH. A duration of the transmission on the PCH may be provided by a duration field of frame 1104, a transmission opportunity (TXOP) duration field of an inter-BSS PPDU (e.g., OBSS PPDU) comprising frame 1104, or a length field of the inter-BSS PPDU.PCT / US25 / 48151 26 September 2025 (26.09.2025)Docket No.: 24-3044 PCTThe AP and STA may set their NAVs for the PCH based on the duration of the OBSS transmission on the PCH (OBSS NAV duration).

[0125] In accordance with NPCA operation, on receiving an inter-BSS PPDU and obtaining the OBSS NAV duration, the AP and the STA may be configured to switch to the NPCA PCH for the OBSS NAV duration. In an example, the AP and the STA may switch to the NPCA PCH at time T1 as shown in example 1100. Here, time T 1 may correspond to the time for switching to NPCA PCH after obtaining the OBSS NAV duration. The AP and STA may be configured to finish transmitting on the NPCA PCH before an end of the OBSS NAV duration and to return to the PCH by the end of the OBSS NAV duration.

[0126] In an implementation, after switching to the NPCA PCH, the AP and STA may start a "MediumSyncDelay” timer for the medium synchronization duration of the NPCA PCH (e.g., as indicated in frame 1102). In example 1100, the AP may be a concurrent CCA STA capable of concurrent CS on both the PCH and the NPCA PCH. As such, provided that the NPCA PCH is idle, the AP may access the NPCA PCH, without waiting for expiration of the "MediumSyncDelay” timer, to transmit a frame 1106 on the NPCA PCH. In another example, the STA may be a non-concurrent CCA STA. On switching to the NPCA PCH, the STA may not be aware of whether a transmission is ongoing on the NPCA PCH. The STA may thus be configured to sense the NPCA PCH until the “MediumSyncDelay” timer expires, before attempting to access the NPCA PCH. However, the STA may acquire medium synchronization on the NPCA PCH before expiration of the “MediumSyncDelay” timer if the STA receives a frame indicating NAV information on the NPCA PCH. For example, the STA may acquire medium synchronization on the NPCA PCH on receiving frame 1106 from the AP. The STA may reset the “MediumSyncDelay” timer to zero and may then proceed to access the NPCA PCH, after performing a random backoff, to transmit a frame (not shown in FIG. 11) on the NPCA PCH.

[0127] In basic NPCA operation, a STA (AP STA or non-AP STA) may be configured to switch to the NPCA PCH only when the STA is able to obtain the OBSS NAV duration from the inter-BSS PPDU. In some cases, however, the STA may fail to obtain the OBSS NAV duration from the inter-BSS PPDU. For example, a TXOP field of the inter-BSS PPDU (which indicates a TXOP duration associated with the inter-BSS PPDU) may be set to “UNSPECIFIED” and the STA may fail to decode MPDU(s) contained in the inter-BSS PPDU to obtain the TXOP duration. This failure to obtain the OBSS NAV duration may result in a non-AP STA not switching to the NPCA PCH despite detecting the inter-BSS PPDU on the PCH (not shown in FIG. 11). As such, the non-AP STA may remain on the PCH, while the AP STA switches to the NPCA PCH for the duration of the OBSS NAV. The non-AP STA may fail to receive frame 1106 transmitted by the AP STA and may be deprived from communication until the AP STA returns to the PCH at the end of the OBSS NAV duration.

[0128] To mitigate this potential problem, in an enhanced NPCA operation, a STA (AP STA or non-AP STA) may be configured to switch to the NPCA PCH on detecting an inter-BSS PPDU on the PCH even when the STA is unable to determine the OBSS NAV duration from the inter-BSS PPDU. With a non-AP STA switching to the NPCA PCH without having determined the OBSS NAV duration, the non-AP STA may not havePCT / US25 / 48151 26 September 2025 (26.09.2025)Docket No.: 24-3044 PCT knowledge of the time at which the AP STA will return to the PCH. In an implementation, after switching to the NPCA PCH, an AP STA may be configured to transmit on the NPCA PCH a frame that indicates a duration based on the OBSS NAV duration. The frame informs the non-AP STA of the time at which the non-AP STA should return to the PCH.

[0129] The time at which a STA (AP STA or non-AP STA) switches from the PCH to the NPCA PCH may be based on an NPCA switching mode used by the STA. Specifically, the NPCA switching mode used by the STA indicates a time at which the STA switches from the PCH to the NPCA PCH after receiving an inter-BSS PPDU on the PCH.

[0130] According to a first mode (hereinafter also referred to as Mode 1), the STA switches from the PCH to the NPCA PCH after receiving a signal field of a PPDU being received on the PCH and determining based on the signal field that the PPDU is an inter-BSS PPDU. In an implementation, the signal field may be comprised in a PHY portion (e.g., PHY header) of the PPDU. For example, the signal field may be a very high throughput (VHT)-SIG-A field of a VHT PPDU, a high efficiency (HE)-SIG-A field of an HE PPDU, or a universal signal (U-SIG) field of an extremely high throughput (EHT) PPDU or an ultra-high reliability (UHR) PPDU. In an implementation, the signal field comprises a BSS color field that allows the STA to determine whether the PPDU is an inter-BSS PPDU (OBSS PPDU) or an intra-BSS PPDU. In an implementation, the signal field comprises a partial AID field (e.g., in VHT-SIG-A) that allows the STA to determine whether the PPDU is an inter-BSS PPDU (OBSS PPDU) or an intra-BSS PPDU. In an implementation, the signal field comprises a group ID field (e.g., in VHT-SIG-A) that allows the STA to determine whether the PPDU is an inter-BSS PPDU (OBSS PPDU) or an intra-BSS PPDU or whether the PPDU is for a DL transmission, a UL transmission, or an SU / MU transmission. In an implementation, the signal field comprises a TXOP field that indicates a TXOP duration associated with the PPDU. After determining that the PPDU is an inter-BSS PPDU based on the BSS color field, the STA may be configured to determine the OBSS NAV duration based on the TXOP field of the signal field of the PPDU. According to this implementation, the STA may be configured to switch from the PCH to the NPCA PCH after reading the TXOP field of the signal field of the PPDU, regardless of whether the STA is able to determine the OBSS NAV duration based on the TXOP field. That is, after reading the TXOP field of the PPDU, the STA may stop processing / decoding the PPDU and may switch immediately to the NPCA PCH. In an implementation, when the STA does not determine the OBSS NAV before switching to the NPCA PCH, the STA may be configured to return to the PCH at or before the end of the inter-BSS PPDU.

[0131] According to a second mode (hereinafter also referred to as Mode 2), after determining that a PPDU being received on the PCH is an inter-BSS PPDU and failing to determine / obtain the OBSS NAV duration (e.g., based on the TXOP field of the signal field of the PPDU or based on the absence of a TXOP field in the signal field), the STA may continue to process the PPDU to read / decode one or more MPDU (indicating the TXOP duration associated with the PPDU) contained in the PPDU. In an implementation, the STA mayPCT / US25 / 48151 26 September 2025 (26.09.2025)Docket No.: 24-3044 PCT be configured to switch from the PCH to the NPCA PCH after reading / decoding (or trying to read / decode) the one or more MPDU of the PPDU, regardless of whether the STA is able to determine the OBSS NAV duration based on the TXOP duration. That is, after reading / decoding (or trying to read / decode) the one or more MPDU of the PPDU, the STA may stop processing / decoding the PPDU and may switch immediately to the NPCA PCH. In an implementation, the STA may be configured to read / decode (or try to read / decode) a first occurring MPDU (ora fixed number of first occurring MPDUs) ofthe PPDU before switching to the NPCA PCH. In another implementation, the STA may be configured to read / decode (or try to read / decode) a delimiter of a first occurring MPDU PPDU before switching to the NPCA PCH. In an implementation, when the STA does not determine the OBSS NAV before switching to the NPCA PCH, the STA may be configured to return to the PCH at or before the end ofthe inter-BSS PPDU.

[0132] In an implementation, different STAs (e.g., the AP and STA illustrated in FIG. 11) may support the same NPCA switching modes and may activate or use the same NPCA switching modes during NPCA operation. As a result, different STAs may switch to the NPCA PCH at the same time, in response to the same inter-BSS PPDU detected on the PCH. The switching of STAs from PCH to NPCA PCH using the NPCA switching Mode 1, discussed above, is illustrated in example 1200 of FIG. 12. The switching of STAs from PCH to NPCA PCH using the NPCA switching Mode 2, also discussed above, is illustrated in example 1300 of FIG. 13.

[0133] As shown in FIG. 12, example 1200 includes an AP and a STA associated with the AP. In an example, the AP and the STA may both support NPCA operation and may be using the same NPCA switching modes. Specifically, the AP and the STA may be using the first mode (Mode 1) described above. That is, the AP and the STA may be configured to switch to the NPCA PCH after reading the signal field (or the TXOP field of the signal field) of the inter-BSS PPDU, regardless of whether the AP and the STA determine the OBSS NAV duration (e.g., based on the signal field).

[0134] In example 1200, it is assumed, for the purpose of illustration, that the TXOP field of the inter-BSS PPDU is set to “UNSPECIFIED." On detecting the inter-BSS PPDU on the PCH, the AP and the STA may read the BSS color field of the signal field of the PPDU to determine that the PPDU is an inter-BSS PPDU (OBSS PPDU). The AP and the STA may then read the TXOP field ofthe signal field of the inter-BSS PPDU to determine the OBSS NAV duration. Based on using the first mode, the AP and the STA switch to the NPCA PCH after reading the TXOP field, regardless of whether the AP and the STA are able to determine the OBSS NAV duration from the TXOP field. Specifically, as shown in example 1200, the AP and the STA switch to the NPCA PCH at a time T2, immediately after reading the TXOP field of the inter-BSS PPDU. As the TXOP field of the inter-BSS PPDU is set to “UNSPECIFIED” in example 1200, the AP and the STA switch to the NPCA PCH without knowledge of the OBSS NAV duration. Accordingly, in an implementation, the AP and the STA may return to the PCH at or before the end of inter-BSS PPDU.PCT / US25 / 48151 26 September 2025 (26.09.2025)Docket No.: 24-3044 PCT

[0135] On switching to NPCA PCH, the AP may send a frame to the STA to initiate communication in the NPCA PCH. Having moved to NPCA PCH at time T2, the STA may receive the frame and respond to it.

[0136] As shown in FIG. 13, example 1300 includes an AP and a STA associated with the AP. In an example, the AP and the STA may both support NPCA operation and may be using the same NPCA switching modes. Specifically, the AP and the STA may be using the second mode (Mode 2) described above. That is, the AP and the STA may be configured to switch to the NPCA PCH only after reading / decoding a first occurring MPDU of the inter-BSS PPDU, to try to determine the OBSS NAV duration based on a TXOP duration indicated in the first occurring MPDU.

[0137] On detecting the inter-BSS PPDU, the AP and the STA may read the BSS color field of the signal field of the PPDU to determine that the PPDU is an inter-BSS PPDU (OBSS PPDU). The AP and the STA may then read the TXOP field of the signal field of the inter-BSS PPDU to determine the OBSS NAV duration. Based on the TXOP field of the inter-BSS PPDU being set to “UNSPECIFIED” and the AP and the STA using the second NPCA switching mode, the AP and the STA may continue processing / reading the inter-BSS PPDU to read / decode the first occurring MPDU of the inter-BSS PPDU. After reading / decoding the first occurring MPDU, and regardless of whether the AP and the STA determine the OBSS NAV duration based on a TXOP duration indicated in the first occurring MPDU, the AP and the STA switch to the NPCA PCH. Specifically, as shown in example 1300, the AP and the STA switch to the NPCA PCH, at a time T3, immediately after reading / decoding the first occurring MPDU of the inter-BSS PPDU. It is assumed in example 1300, for the purpose of illustration, that the AP and the STA fail to determine the OBSS NAV duration from the first occurring MPDU (e.g., the AP and the STA fail to decode the first occurring MPDU) and therefore switch to the NPCA PCH without knowledge of the OBSS NAV duration. Accordingly, in an implementation, the AP and the STA may return to the PCH at or before the end of the inter-BSS PPDU (e.g., if the AP and the STA do not get the OBSS NAV duration of the inter-BSS PPDU on NPCA PCH). In another implementation, the AP and the STA may return to the PCH at or before the end of the OBSS NAV duration (e.g., if the AP and the STA get the OBSS NAV duration of the inter-BSS PPDU on NPCA PCH).

[0138] On switching to NPCA PCH, the AP may send a frame to the STA to initiate communication in the NPCA PCH. Having moved to NPCA PCH at time T3, the STA may receive the frame and respond to it.

[0139] As illustrated in examples 1100, 1200 and 1300, the AP and the STA may be configured to switch from the PCH to NPCA PCH at the same time based on using the same NPCA switching mode. Hence, on receiving the inter-BSS PPDU, the AP and the STA may switch from the PCH to NPCA PCH simultaneously. However, if the STA associated with the AP is far away from an OBSS AP, or an OBSS STA, transmitting an inter-BSS PPDU (e.g., in terms of physical or transmission distance), the STA may not receive the inter-BSS PPDU and may not switch to the NPCA PCH. This problem is discussed further, below, in relation to FIG. 14.PCT / US25 / 48151 26 September 2025 (26.09.2025)Docket No.: 24-3044 PCT

[0140] FIG. 14 illustrates a problem that may arise during NPCA operation. As shown in FIG. 14, example 1400 includes an AP and a STA associated with the AP. As in FIGS. 11-13, above, the AP and the STA may both support NPCA operation and may be using the same NPCA switching modes. The AP and the STA may operate over a plurality of channels, including a primary channel (PCH), an NPCA primary channel (NPCA PCH), a first secondary channel (SCH1), and a second secondary channel (SCH2).

[0141] In an example, as discussed above in relation to FIG. 11 and in accordance with NPCA operation, on receiving an inter-BSS PPDU (OBSS PPDU) and obtaining the OBSS NAV duration, the AP and the STA may switch to the NPCA PCH for the OBSS NAV duration. In another example, as discussed above in relation to FIG. 12, the AP and the STA may switch to the NPCA PCH after reading the signal field (or the TXOP field of the signal field) of the inter-BSS PPDU, regardless of whether the AP and the STA determine the OBSS NAV duration (e.g., based on the signal field). In another example, as discussed above in relation to FIG. 13, the AP and the STA may switch to the NPCA PCH only after reading / decoding a first occurring MPDU of the inter-BSS PPDU to try to determine the OBSS NAV duration based on a TXOP duration indicated in the first occurring MPDU. In all of these examples, the AP and the STA switch from the PCH to the NPCA PCH on receiving an inter-BSS PPDU and processing it.

[0142] In example 1400, on receiving the inter-BSS PPDU, the AP may switch to the NPCA PCH, at a time T, after processing the inter-BSS PPDU. But the STA, in this example, may be outside the communication range of an OBSS AP or an OBSS STA transmitting the inter-BSS PPDU, and so may not receive the inter- BSS PPDU and may not switch to the NPCA PCH. Thus, despite having the same configuration as the AP for switching to the NPCA PCH, the STA may remain on the PCH, while the AP STA switches to the NPCA PCH for the duration of the OBSS NAV or for the duration of the inter-BSS PPDU.

[0143] After switching to the NPCA PCH, the AP may transmit a frame to the STA in the NPCA PCH, not knowing whether the STA has also switched to the NPCA PCH. The STA may fail to receive the frame transmitted by the AP in the NPCA PCH . Not receiving a response from the ST A, the AP may transmit another frame to another STA to initiate communication until the AP receives a response from another STA (not shown in FIG. 14). As such, NPCA PCH resources, as well as AP resources, used to transmit one or more frames to the STAs to initiate communication, may be wasted.

[0144] Embodiments of the present disclosure, as further described below, address the above-discussed problem of existing technologies. In an aspect, a first AP determines that a PPDU being received via a PCH comprises an inter-BSS PPDU (e.g., OBSS PPDU). The first AP then transmits, via the PCH and during a duration associated with the PPDU, a frame instructing a STA, associated with the first AP, to switch from the PCH to a NPCA PCH. This may help the first STA switch from the PCH to the NPCA PCH, if the first STA does not receive the PPDU. The transmitting of the frame is based on the determining that the PPDU comprises the inter-BSS PPDU. In an embodiment, the transmitting of the frame comprises transmitting using a power level based on a parameter, where the parameter comprises at least one of an accepted receivedPCT / US25 / 48151 26 September 2025 (26.09.2025)Docket No.: 24-3044 PCT interference level (ARIL) of the frame at the destination STA of the PPDU or a transmit power level of the PPDU. In another embodiment, the transmitting of the frame comprises transmitting the frame using beamforming weights. Determining one or more of a transmit power level or beamforming weights may help avoid or minimize interference to the destination STA of the PPDU, while helping the first STA switch from the PCH to the NPCA PCH. As such, loss of NPCA PCH resources (and the first AP resources) by transmitting frames to the first STA that has not switched to the NPCA PCH may be avoided, while minimizing the interference level to the destination STA.

[0145] FIG. 15 shows an example 1500 that illustrates an example NPCA operation according to an embodiment. As shown in FIG. 15, example 1500 includes STAs 1502 and 1504. STAs 1502 and 1504 may belong to the same BSS. Each of STAs 1502 and 1504 may be an AP STA or a non-AP STA. In an embodiment, STA 1502 may be an AP STA, and STA 1504 may be a non-AP STA, or vice versa. In an embodiment, where STA 1502 is an AP STA and STA 1504 is a non-AP STA, STA 1504 may be associated with STA 1502. In an embodiment, STAs 1502 and 1504 may both support NPCA operation and may operate over a plurality of channels, including a primary channel (PCH), an NPCA primary channel (NPCA PCH), a first secondary channel (SCH1), and a second secondary channel (SCH2). For example, where STA 1502 and / or STA 1504 is an AP STA, the respective STA may be referred to as an NPCA AP. Where STA 1502 and / or STA 1504 is a non-AP STA, the respective STA may be referred to as an NPCA STA. In an embodiment, each of STAs 1502 and 1504 may support the NPCA switching modes described above. In an embodiment, each of STAs 1502 and 1504 may be configured to support the same NPCA switching mode. For example, STAs 1502 and 1504 may each support PHY Header-based (PHYLEN) NPCA operation and / or MAC Header-based (MOPLEN) NPCA operation, as discussed above in relation to FIGS. 9-10. Further, STAs 1502 and 1504 may each switch from a PCH to an NPCA PCH based on satisfying either condition 1) or condition 2), described above in relation to FIGS. 9-10.

[0146] As shown in FIG. 15, example 1500 may begin with a transmission of a PPDU 1506 on the PCH. PPDU 1506 may be transmitted by a station that belongs to an OBSS relative to the BSS of STAs 1502 and 1504 (e.g., STAs 1502 and 1504 be associated with a same BSS, while PPDU 1506 is transmitted by a STA associated with a different BSS). In an example, STA 1502 may be within the communication range of the station (e.g., the OBSS STA) that transmitted PPDU 1506. In an example, STA 1504 may be outside the communication range of the station (e.g., the OBSS STA) that transmitted PPDU 1506. In an embodiment, PPDU 1506 may be transmitted by an OBSS AP. In an embodiment, STA 1502 may receive PPDU 1506, but STA 1504 may not receive PPDU 1506. Operating on the PCH, STA 1502 may detect / sense the transmission of PPDU 1506 and begin to read / decode PPDU 1506.

[0147] On reading / decoding PPDU 1506, STA 1502 may determine that PPDU 1506 being received via the PCH is an inter-basic service set (inter-BSS) PPDU. In an embodiment, determining that PPDU 1506 is an inter-BSS PPDU comprises decoding a signal (SIG) field of PPDU 1506. In an embodiment, PPDU 1506 mayPCT / US25 / 48151 26 September 2025 (26.09.2025)Docket No.: 24-3044 PCT comprise a preamble part (or PHY header), where the preamble part (or PHY header) may comprise the SIG field. Depending on the type of PPDU 1506, the SIG field may comprise a U-SIG, a UHR SIG, an EHT SIG, an HE SIG-A / B, aVHT SIG-A / B, or an HT SIG, for example. In an embodiment, where PPDU 1506 comprises an EHT PPDU, a UHR PPDU, ora UHR+ PPDU, where UHR+ PPDU may comprise future generation PPDUs after the UHR PPDU, the SIG field comprises a U-SIG field of the PPDU. In an embodiment, where PPDU 1506 comprises an HE PPDU, the SIG field comprises an HE-SIG-A field of the PPDU. In an embodiment, where PPDU 1506 comprises a VHT PPDU, the SIG field comprises a VHT-SIG-A field of the PPDU. In an embodiment, the SIG field may comprise a BSS color field set to a BSS color different than a BSS color of STA 1502, and the STA can use that difference to identify the PPDU 1506 as an inter-BSS PPDU: STA 1502 may determine that PPDU 1506 is an inter-BSS PPDU based on identifying the BSS color difference between PPDU 1506 and STA 1502. It is noted that STA 1502 may determine that PPDU 1506 is an inter-BSS PPDU before, or without, receiving PPDU 1506 fully.

[0148] In addition to determining whether PPDU 1506 comprises an inter-BSS PPDU, STA 1502 may obtain a value of the duration associated with PPDU 1506, based on PPDU 1506. In an embodiment, obtaining a value of the duration may comprise identifying the duration. For example, STA 1502 may obtain the value of the duration from a duration field of a PHY header of the PPDU. Alternatively, or in addition, STA 1502 may obtain the value of the duration from a duration field of a medium access control (MAC) header of the PPDU. In an embodiment, the duration associated with PPDU 1506 may be the duration of the OBSS NAV, based on the TXOP field of the signal field of the PPDU. In another embodiment, the duration associated with PPDU 1506 may be the duration of the PPDU. For example, STA 1502 may support PHYLEN NPCA operation and / or MOPLEN NPCA operation, as discussed above in relation to FIGS. 9-10, and may determine whether to switch from the PCH to the NPCA PCH based on satisfying either condition 1) or condition 2), described above in relation to FIGS. 9-10.

[0149] In an embodiment, before switching from the PCH to the NPCA PCH, STA 1502 may be configured to instruct its associated STAs to switch from the PCH to the NPCA PCH. As such, STAs that may not have received PPDU 1506 may also switch to the NPCA PCH based on receiving an instruction from STA 1502.

[0150] In another embodiment, STA 1502 may suggest / recommend to its associated STAs to switch from the PCH to the NPCA PCH, before STA 1502 switches from the PCH to the NPCA PCH. As such, STAs that may not have received PPDU 1506 may decide based on receiving a suggestion / recommendation from STA 1502. In an embodiment, STAs that may not have received PPDU 1506 may also switch to the NPCA PCH based on the suggestion / recommendation. In another embodiment, STAs that may not have received PPDU 1506 may prefer to stay on the PCH, despite the suggestion / recommendation.

[0151] In another embodiment, STA 1502 may be configured to inform / notify / announce to / report to its associated STAs, before STA 1502 switches from the PCH to the NPCA PCH, that STA 1502 is going to switch from the PCH to the NPCA PCH (based on STA 1502 detecting an inter-BSS PPDU). As such, STAsPCT / US25 / 48151 26 September 2025 (26.09.2025)Docket No.: 24-3044 PCT that may not have received PPDU 1506 may be aware that STA 1502 is going to switch from the PCH to the NPCA PCH. In a further embodiment, being informed by STA 1502, STAs that may not have received PPDU 1506 may also determine to switch to the NPCA PCH based on the information provided by STA 1502. In another further embodiment, despite being informed by STA 1502, STAs that may not have received PPDU 1506 may prefer to stay on the PCH.

[0152] In example 1500, STA 1502 may be configured to instruct / request its associated STAs to switch from the PCH to the NPCA PCH, before switching from the PCH to the NPCA PCH. While example 1500 illustrates STA 1502 instructing / requesting its associated STAs to switch from the PCH to the NPCA PCH, example 1500 may be readily extended to STA 1502 suggesting / recommending to its associated STAs to switch from the PCH to the NPCA PCH, or to STA 1502 informing / notifying / reporting / announcing to its associated STAs that STA 1502 is going to switch from the PCH to the NPCA PCH. For example, STA 1502 may support PHYLEN NPCA operation and / or MOPLEN NPCA operation, as discussed above in relation to FIGS. 9-10, and may instruct / request / suggest / recommend / inform / notify / report / announce to its associated STAs to switch from the PCH to the NPCA PCH based on STA 1502 satisfying either condition 1) or condition 2), described above in relation to FIGS. 9-10.

[0153] In an embodiment, STA 1502 may determine whether STA 1504, an associated STA of STA 1502, is outside a communication range of PPDU 1506, based on information received from STA 1504. In an embodiment, the information may comprise a list of BSSs for which STA 1504 is inside communication range. That is, STA 1502 (e.g ., an AP STA) can determine whether STA 1504 is outside communication range of PPDU 1506 by receiving a list of BSSs for which STA 1504 is inside communication range, and determining that the BSS associated with the STA transmitting PPDU 1506 is not included in this list. As such, STA 1502 may transmit a frame to STA 1504 to instruct STA 1504 to switch from the PCH to the NPCA PCH, based on STA 1504 being outside the communication range of the STA transmitting PPDU 1506. In another embodiment, STA 1502 may not have a priori information comprising a list of BSSs for which STA 1504 is inside the communication range. Regardless, STA 1502 may transmit a frame to STA 1504 to instruct STA 1504 to switch from the PCH to the NPCA PCH, as discussed further below, whether or not STA 1502 has information about STA 1504 being outside the communication range of the STA transmitting PPDU 1506. In another embodiment, STA 1502 may transmit a frame to all of its associated STAs (e.g., using a broadcast receiver address) to instruct all associated STAs to switch from the PCH to the NPCA PCH (not shown in FIG. 15).

[0154] In an embodiment, STA 1502 may instruct STA 1504 to switch from the PCH to the NPCA PCH based on determining PPDU 1506 comprises an inter-BSS PPDU. For example, as illustrated in example 1500, after determining PPDU 1506 comprises the inter-BSS PPDU and obtaining a value of the duration associated with PPDU 1506, STA 1502 may transmit, via the PCH and during the duration associated with PPDU 1506, a frame 1508 instructing STA 1504, associated with STA 1502, to switch from the PCH to thePCT / US25 / 48151 26 September 2025 (26.09.2025)Docket No.: 24-3044 PCTNPCA PCH. In an embodiment, the transmitting of frame 1508 may be based on the determining that PPDU 1506 comprises the inter-BSS PPDU. For example, STA 1502 may transmit frame 1508 via the PCH by not updating a basic network allocation vector (NAV) timer with the duration associated with PPDU 1506 (e.g ., not updating the basic NAV timer based on the determining that PPDU 1506 comprises the inter-BSS PPDU). In an embodiment, not updating the basic NAV timer may comprise ignoring the duration associated with the PPDU. In another embodiment, not updating the basic NAV timer may comprise not setting the basic NAV timer to the duration.

[0155] In another embodiment, after determining PPDU 1506 comprises the inter-BSS PPDU and obtaining the value of the duration associated with PPDU 1506, STA 1502 may update a basic NAV timer with the duration associated with the PPDU. For example, STA 1502 may ignore the updated basic NAV timer for the transmitting of frame 1508. Alternatively, or in addition, the STA 1502 may update the basic NAV timer after transmitting frame 1508.

[0156] In an embodiment, frame 1508 may include a management frame, an action frame, a control frame, a quality of service (QoS) null frame, a QoS data frame, or any other suitable frame. In an example, frame 1508 may be a trigger frame (e.g., an MU-RTS trigger frame or another suitable trigger frame), and the instruction for STA 1504 to switch from the PCH to the NPCA PCH may be included in a common info field of the trigger frame (e.g., a common info field of a MU-RTS trigger frame). In an embodiment, frame 1508 may further comprise the duration associated with PPDU 1506.

[0157] After transmitting PPDU 1506, STA 1502 may switch from the PCH to the NPCA PCH. In an example, the switching may be at time T.

[0158] In example 1500, STA 1504 may receive from STA 1502, via the PCH and during the duration associated with PPDU 1506, frame 1508. Frame 1508 may be instructing STA 1504, associated with STA 1502, to switch from the PCH to the NPCA PCH.

[0159] In an embodiment, after receiving frame 1508, STA 1504 may switch from the PCH to the NPCA PCH. In an example, the switching may be at time T (e.g., the same switching time as STA 1502). Furthermore, STA 1504 may update the basic NAV timer with the duration associated with PPDU 1506. In an example, the basic NAV timer may be for the PCH. In an embodiment, the updating of the basic NAV timer may be performed before switching from the PCH to the NPCA PCH. In another embodiment, the updating of the basic NAV timer may be performed at a time of switching from the PCH to the NPCA PCH. In another embodiment, the updating of the basic NAV timer may be performed after switching from the PCH to the NPCA PCH.

[0160] Continuing with example 1500, after switching to the NPCA PCH, STA 1502 may access the NPCA PCH and transmit a frame 1510 to STA 1504. As shown in FIG. 15, frame 1510 may be transmitted via a bandwidth that comprises the NPCA PCH. For example, frame 1510 may be transmitted via the NPCH PCH and SCH2. In an embodiment, STA 1502 may transmit frame 1510 after switching to the NPCA PCH.PCT / US25 / 48151 26 September 2025 (26.09.2025)Docket No.: 24-3044 PCTSpecifically, in example 1500, after instructing STA 1504 to switch to the NPCA PCH at time T, STA 1502 may expect that STA 1504 is ready / available to receive via the NPCA PCH after time T. STA 1502 may thus transmit frame 1510 at a transmission time based on T (e.g., immediately after T, after a random backoff from T, a SIPS after T, etc.). Frame 1510 may comprise an initial control frame (IGF), a request-to-send (RTS) frame, a multi-user (MU)-RTS frame, a buffer status report poll (BSRP) trigger frame, a block ack request (BAR) frame, a clear-to-send (CTS) frame, a block ack (BA) frame, an acknowledgment (Ack) frame, a buffer status report (BSR) frame, an initial control response frame (ICR), a control frame, a management frame, or an action frame, for example.

[0161] In an embodiment, STA 1504 may respond to frame 1510 from STA 1502 by transmitting a frame 1512 to STA 1502. Frame 1512 may comprise a clear-to-send (CTS) frame, a BlockAck (BA) frame, an acknowledgment (Ack) frame, a buffer status report (BSR) frame, an initial control response frame (ICR), a control frame, a management frame, or an action frame, for example. Subsequently, STA 1502 may transmit a frame 1514 to STA 1504. Frame 1514 may comprise a data frame, a management frame, or an action frame, for example. STA 1504 may respond to frame 1514 by transmitting a frame 1516 to STA 1502. Frame 1516 may comprise an immediate response frame, such as an Ack frame or a BA frame. As such, successful communication may occur between STAs 1502 and 1504 on the NPCA PCH after STA 1504 switches to the NPCA PCH after receiving frame 1508. STAs 1502 and 1504 may be configured to finish communicating on the NPCA PCH and return to the PCH before an end of PPDU 1506 or by the end of OBSS NAV duration.

[0162] FIG. 16 shows an example 1600 that illustrates another example NPCA operation according to an embodiment. As shown in FIG. 16, example 1600 includes STAs 1602 and 1604. As discussed above for STAs 1502 and 1504 illustrated in FIG. 15, STAs 1602 and 1604 may belong to the same BSS, may each be an AP STA or a non-AP STA, and may both support NPCA operation. In an embodiment, STA 1602 may be an AP STA, and STA 1604 may be a non-AP STA associated with AP STA 1602. STA 1602 may be referred to as an NPCA AP. STA 1604 may be referred to as an NPCA STA. Like STAs 1502 and 1504 illustrated in FIG. 15, STAs 1602 and 1604 may each support PHYLEN NPCA operation and / or MOPLEN NPCA operation, as discussed above in relation to FIGS. 9-10, and STAs 1602 and 1604 may each switch from a PCH to an NPCA PCH based on satisfying either condition 1) or condition 2), described above in relation to FIGS. 9-10.

[0163] As shown in FIG. 16, example 1600 may begin with a transmission of a PPDU 1606 on the PCH. PPDU 1606 may be transmitted by a station that belongs to an OBSS relative to the BSS of STAs 1602 and 1604 (e.g., STAs 1602 and 1604 be associated with a same BSS, while PPDU 1606 is transmitted by a STA associated with a different BSS).

[0164] In an embodiment, PPDU 1606 may be transmitted by an OBSS AP. In example 1600, PPDU 1606 may be a PPDU, similar to PPDU 1506, addressed to a destination STA associated with the OBSS AP. In an example, STA 1602 may be within the communication range of the station (e.g., the OBSS AP) thatPCT / US25 / 48151 26 September 2025 (26.09.2025)Docket No.: 24-3044 PCT transmitted PPDU 1606. In an example, STA 1604 may be outside the communication range (e.g., the OBSS AP) of the station that transmitted PPDU 1606. In an embodiment, STA 1602 may receive PPDU 1606, but STA 1604 may not receive PPDU 1606. Operating on the PCH, STA 1602 may detect / sense the transmission of PPDU 1606 and begin to read / decode PPDU 1606.

[0165] Similar to STA 1502 illustrated in FIG. 15, STA 1602 may determine that PPDU 1606 is an inter-BSS PPDU. This is discussed further, above, in relation to FIG. 15. In addition to determining PPDU 1606 is an inter-BSS PPDU, like STA 1502 illustrated in FIG. 15, STA 1602 may obtain a value of the duration associated with PPDU 1606. This is also discussed further, above, in relation to FIG. 15. For example, STA 1602 may support PHYLEN NPCA operation and / or MOPLEN NPCA operation, as discussed above in relation to FIGS. 9-10, and may determine whether to switch from the PCH to the NPCA PCH based on satisfying either condition 1) or condition 2), described above in relation to FIGS. 9-10.

[0166] In example 1600, PPDU 1606 may further include a parameter 1607. In an embodiment, parameter 1607 may be in the PHY header of PPDU 1606, in the MAC header of PPDU 1606, or in any other suitable aspect of the PPDU 1606. STA 1602 may read / decode PPDU 1606 to determine parameter 1607, and, in an embodiment, STA 1602 may use parameter 1607 for transmitting a frame (e.g., a frame 1608) instructing STA 1604, associated with STA 1602, to switch from the PCH to the NPCA PCH. In illustrated example 1600, PPDU 1606 includes parameter 1607, but this is merely an example. As discussed further, below, with regard to FIG. 17, parameter 1607 may be transmitted separately from PPDU 1606 (e.g., as part of another frame transmitted before PPDU 1606).

[0167] In an embodiment, parameter 1607 may comprise an accepted received interference level (ARIL) of frame 1608 at the destination STA of PPDU 1606, a transmit power level of PPDU 1606, both, or any other suitable parameter(s). STA 1602 may transmit frame 1608 using a power level based on at least one of the ARIL of frame 1608 at the destination STA of PPDU 1606 or the transmit power level of PPDU 1606, as discussed further below. In another embodiment, parameter 1607 may comprise a set of beamforming weights, and STA 1602 may transmit frame 1608 using the beamforming weights as part of a beamforming or coordinated beamforming (CBF) transmission, discussed further below.

[0168] Further, in another embodiment, parameter 1607 may comprise a location of the destination STA of PPDU 1606, and STA 1602 may transmit frame 1608 considering the location . For example, parameter 1607 may indicate the position of the destination STA (e.g., coordinates of the destination STA) or any other suitable location information. STA 1602 may use the position information to minimize interference to the destination STA of PPDU 1606. For example, considering the position of the destination STA of PPDU 1606, STA 1602 may use nulls towards the destination STA of PPDU 1606 if STA 1602 is using beamforming or coordinated beamforming when transmitting frame 1608. In another example, considering the position of the destination STA of PPDU 1606, STA 1602 may calculate the ARIL of frame 1608 at the destination STA of PPDU 1606, if STA 1602 is using a transmit power control mechanism such as spatial reuse.PCT / US25 / 48151 26 September 2025 (26.09.2025)Docket No.: 24-3044 PCT

[0169] In an embodiment, PPDU 1606 may further include a spatial reuse field. In an embodiment, the spatial reuse field of PPDU 1606 may be set to a value that allows spatial reuse, permits spatial reuse, or does not prohibit spatial reuse. STA 1602 may transmit frame 1608 using spatial reuse, as discussed further below.

[0170] For example, two independent spatial reuse modes are defined for both HE and EHT STAs: OBSS Packet Detect (PD)-based Spatial Reuse (OBSS PD-based SR) and Parameterized Spatial Reuse (PSR)- based Spatial Reuse (PSR-based SR). An additional spatial reuse method has further been developed for UHR STAs: Coordinated spatial reuse (CSR). In an embodiment, STA 1602 may use parameter 1607 and one of OBSS PD-based SR, PSR-based SR, or CSR, to transmit frame 1608 to STA 1604, instructing STA 1604 to switch from the PCH to the NPCA PCH.

[0171] First, OBSS PD-based SR is a spatial reuse mode in which STAs, under specific conditions, may ignore an inter-BSS PPDU when a sensitivity level (called the OBSS PD level) is lower than a preamble detect clear channel assessment (CCA) sensitivity level. The preamble detect CCA sensitivity level is -82dBm for 20MHz signals and increases proportional to bandwidth of the signal (e.g. -79dBm for 40MHz and -76dBm for 80MHz). Note that unlike the CCA sensitivity level, the OBSS PD level may be controlled dynamically by a STA to optimize its own Spatial Reuse operation.

[0172] When using OBSS PD-based SR, a STA maintains an OBSS PD level parameter (OBSS_PDIevel) and may adjust this OBSS PD level in conjunction with its transmit power and a value, PPDU_BW, derived from the received PPDU. The adjustment may be made according to OBSS_PDIevel < max (OBSS_PDmin, min(OBSS_PDmax, OBSS_PDmin+(TX_PWRref-TX_PWR)))+10log10(PPDU_BW / 20MHz) where OBSS_PDmin, OBSS_PDmax, TX_PWRref are parameters that are constant or in some conditions, advertised by the AP using information elements in management frames. The TX_PWRref is a reference Transmit Power used in OBSS PD-based SR mechanism and may have a value of either 21 dBm or 25dBm depending on whether a STA or an AP is transmitting. The OBSS_PDmin and OBSS_PDmax on the other hand are parameters decided by the AP and may be advertised in management frames that it transmits. The AP uses this pair of parameters to control the level of aggressiveness of STAs within its BSS when using OBSS PD-based SR access.

[0173] In an embodiment, parameter 1607 includes a transmit power level of PPDU 1606, which STA 1602 uses to transmit frame 1608 using OBSS PD-based SR (e.g., along with any other parameters, including parameters provided in previous transmissions).

[0174] Second, PSR-based SR is another spatial reuse mode supported in HE and EHT devices. This opportunistic spatial reuse mode allows a STA to transmit within a duration of a TB PPDU sent from an OBSS network. Opportunities for PSR-based SR are identified by the reception of an inter-BSS PPDU that contains a TF. Due to the controlled nature of the TB PPDU response in terms of transmit power and duration, constraints regarding spatial reuse interference may be set with ease.PCT / US25 / 48151 26 September 2025 (26.09.2025)Docket No.: 24-3044 PCT

[0175] An AP that allows PSR-based SR may specify its own acceptable interference levels dynamically for each TB PPDU it solicits. For a STA, a PSR-based SR opportunity is identified if the following two conditions are met: Condition 1) The STA receives a Parameterized Spatial Reuse Reception (PSRR) PPDU (a PPDU that is identified as an inter-BSS PPDU and that contains a TF); and Condition 2) The STA has a PPDU queued to be transmitted and the intended transmit power of the PPDU (this PPDU hereinafter is called PSR Transmission PPDU (PSRT PPDU)) in dBm, minus log10(PPDU_BW I 20 MHz) dB, is below a power threshold value PSRT_TXP, where PPDU_BW is a bandwidth value of the PSRR PPDU in MHz.

[0176] In some embodiments, the power threshold value PSRT_TXP is obtained by subtracting a parameter PSR indicated in 1) a UL Spatial Reuse field of the TF contained in the PSRR PPDU or 2) a value in the preamble of a TB PPDU that follows the PSRR PPDU, from a parameter RPL.

[0177] The parameter RPL may be equal to the combined transmit power at the receive antenna connector, over the PSRR PPDU bandwidth, during the non-HE or non-EHT portion of the PSRR PPDU preamble, averaged over all antennas used to receive the PSRR PPDU. In some embodiments, a STA may not be able to obtain an accurate value RPL from the PSRR PPDU and may instead use a value of RPL based on previous received PPDUs (e.g. beacon frames) coming from the AP that transmitted the PSRR PPDU.

[0178] A STA that identifies a PSR-based SR opportunity may issue a reset to its PHY circuitry to ignore (e.g., terminate reception) any TB PPDU(s) that are triggered by the TF contained in the PSRR PPDU, provided that the value of the BSS Color of the TB PPDU matches the BSS Color of the PSRR PPDU . A STA that identifies a PSR-based SR opportunity may not be allowed to transmit a PSRT PPDU that terminates beyond the duration of the TB PPDU that is triggered by the TF contained in the PSRR PPDU.

[0179] In an embodiment, parameter 1607 includes ARIL of frame 1608 at the destination STA of PPDU 1606, which STA 1602 uses to transmit frame 1608 using OBSS PSR-based SR (e.g., along with any other parameters, including parameters provided in previous transmissions).

[0180] Third, CSR is one type of multi-AP coordination that may be supported by multiple APs. Spatial reuse using CSR can be more stable than non-AP coordinated spatial reuse schemes such as OBSS PD-based SR and PSR-based SR. For example, APs may perform a joint sounding operation in order to measure path loss (PL) on paths of the network. For example, the joint sounding operation may result in the measurement of PL for the path between APs, and path losses for the paths between APs and their associated STAs. The measured path loss information may then be shared between APs (e.g., using the backhaul) to allow for simultaneous transmissions by APs to their associated STAs respectively. Specifically, one of APs obtains a TXOP to become the master AP. The master AP may then send a CSR announcement frame to the other AP(s). In an implementation, the master AP may perform a polling operation, before sending the CSR announcement frame, to poll slave APs regarding packet availability for transmission. If at least one slave AP responds indicating packet availability, the master AP may proceed with sending the CSR announcement frame. In the CSR announcement, the master AP may limit the transmit power of a slave AP in order toPCT / US25 / 48151 26 September 2025 (26.09.2025)Docket No.: 24-3044 PCT protect its own transmission to its target STA. The slave AP may similarly protect its own transmission to its target STA by choosing a modulation scheme that enables a high enough Signal to Interference Ratio (SIR) margin to support the interference due to the transmission of the master AP to its target STA.

[0181] In an embodiment, parameter 1607 includes ARIL of frame 1608 at the destination STA of PPDU 1606, which STA 1602 uses to transmit frame 1608 using CSR (e.g., along with any other parameters, including parameters provided in previous transmissions).

[0182] In an embodiment, instead (or in addition to) using spatial reuse or transmit power level control, STA 1602 may use beamforming or CBF to transmit frame 1608 to STA 1604, instructing STA 1604 to switch from the PCH to the NPCA PCH. For example, CBF may be suitable when a receiving STA suffers from potential interference from other APs in a multi-AP group. By using channel related information such as channel state information (CSI), channel quality indication (CQI), or compressed beamforming feedback exchanged among APs, an AP may pre-code a signal to be transmitted to form a beam that increases power toward a target STA while reducing the power that interferes with a STA associated with a neighboring AP.

[0183] In an embodiment, parameter 1607 includes a set of beamforming weights, which STA 1602 uses to transmit frame 1608 using beamforming or CBF (e.g., along with any other parameters, including parameters provided in previous transmissions).

[0184] In addition, as discussed above, the location of the destination STA of PPDU 1606 obtained from parameter 1607 may also be helpful in determining beamforming weights or transmit power level of frame 1608 to be transmitted by STA 1602 during the transmission of PPDU 1606. In an embodiment, the use of spatial reuse or transmit power level control, beamforming, or both for transmission of frame 1608 minimizes or avoids interference to the destination STA of PPDU 1606, stemming from transmission of frame 1608.

[0185] In an embodiment, before switching from the PCH to the NPCA PCH, STA 1602 may be configured to instruct its associated STAs to switch from the PCH to the NPCA PCH. As such, STAs that may not have received PPDU 1606 may also switch to the NPCA PCH based on receiving an instruction from STA 1602.

[0186] In another embodiment, STA 1602 may suggest / recommend to its associated STAs to switch from the PCH to the NPCA PCH, before STA 1602 switches from the PCH to the NPCA PCH. As such, STAs that may not have received PPDU 1606 may decide based on receiving a suggestion / recommendation from STA 1602. In an embodiment, STAs that may not have received PPDU 1606 may also switch to the NPCA PCH based on the suggestion / recommendation. In another embodiment, STAs that may not have received PPDU 1606 may prefer to stay on the PCH, despite the suggestion / recommendation.

[0187] In another embodiment, STA 1602 may be configured to inform / notify / announce to / report to its associated STAs, before STA 1602 switches from the PCH to the NPCA PCH, that STA 1602 is going to switch from the PCH to the NPCA PCH (based on STA 1602 detecting an inter-BSS PPDU). As such, STAs that may not have received PPDU 1606 may be aware that STA 1602 is going to switch from the PCH to the NPCA PCH. In a further embodiment, being informed by STA 1602, STAs that may not have received PPDUPCT / US25 / 48151 26 September 2025 (26.09.2025)Docket No.: 24-3044 PCT1606 may also determine to switch to the NPCA PCH based on the information provided by STA 1602. In another further embodiment, despite being informed by STA 1602, STAs that may not have received PPDU 1606 may prefer to stay on the PCH.

[0188] In example 1600, STA 1602 may be configured to instruct / request its associated STAs to switch from the PCH to the NPCA PCH, before switching from the PCH to the NPCA PCH. While example 1600 illustrates STA 1602 instructing / requesting its associated STAs to switch from the PCH to the NPCA PCH, example 1600 may be readily extended to STA 1602 suggesting / recommending to its associated STAs to switch from the PCH to the NPCA PCH, or to STA 1602 informing / notifying / reporting / announcing to its associated STAs that STA 1602 is going to switch from the PCH to the NPCA PCH. For example, STA 1602 may support PHYLEN NPCA operation and / or MOPLEN NPCA operation, as discussed above in relation to FIGS. 9-10, and may instruct / request / suggest / recommend / inform / notify / report / announce to its associated STAs to switch from the PCH to the NPCA PCH based on STA 1602 satisfying either condition 1) or condition 2), described above in relation to FIGS. 9-10.

[0189] Like STA 1502 illustrated in FIG. 15, before switching from the PCH to the NPCA PCH, STA 1602 may instruct its associated STAs to switch from the PCH to the NPCA PCH. Also like STA 1502 illustrated in FIG. 15, STA 1602 may determine whether STA 1604 is outside the communication range of PPDU 1606 as described further, above, in relation to FIG. 15.

[0190] In example 1600, STA 1602 may instruct STA 1604 to switch from the PCH to the NPCA PCH based on determining PPDU 1606 comprises an inter-BSS PPDU. For example, as illustrated in example 1600, after determining PPDU 1606 comprises the inter-BSS PPDU and obtaining a value of the duration associated with PPDU 1606, STA 1602 may transmit, via the PCH and during the duration associated with PPDU 1606, frame 1608 instructing STA 1604, associated with STA 1602, to switch from the PCH to the NPCA PCH. In an embodiment, the transmitting of frame 1608 may be based on the determining that PPDU 1606 comprises the inter-BSS PPDU.

[0191] Similar to STA 1502 illustrated in FIG. 15, as discussed above STA 1602 may not update a basic NAV timer associated with PPDU 1606. This allows STA 1602 transmit frame 1608 during the transmission of PPDU 1606. In another embodiment, STA 1602 may update a basic NAV timer and ignore the updated basic NAV timer for transmitting frame 1608. Alternatively, or in addition, the STA 1602 may update the basic NAV timer after transmitting frame 1608.

[0192] In an embodiment, frame 1608 may include a management frame, an action frame, a control frame, a quality of service (QoS) null frame, a QoS data frame, or any other suitable frame. In an example, frame 1608 may be a trigger frame (e.g., an MU-RTS trigger frame or another suitable trigger frame), and the instruction for STA 1604 to switch from the PCH to the NPCA PCH may be included in a common info field of the trigger frame (e.g., a common info field of a MU-RTS trigger frame). In an embodiment, frame 1608 may further comprise the duration associated with PPDU 1606.PCT / US25 / 48151 26 September 2025 (26.09.2025)Docket No.: 24-3044 PCT

[0193] After transmitting PPDll 1606, STA 1602 may switch from the PCH to the NPCA PCH . In an example, the switching may be at time T.

[0194] In example 1600, STA 1604 may receive from STA 1602, via the PCH and during the duration associated with PPDU 1606, frame 1608. Frame 1608 may be instructing STA 1604, associated with STA 1602, to switch from the PCH to the NPCA PCH.

[0195] In an embodiment, after receiving frame 1608, STA 1604 may switch from the PCH to the NPCA PCH. In an example, the switching may be at time T (e.g., the same switching time as STA 1602). Furthermore, STA 1604 may update the basic NAV timer with the duration associated with PPDU 1606. In an example, the basic NAV timer may be for the PCH. In an embodiment, the updating of the basic NAV timer may be performed before switching from the PCH to the NPCA PCH. In another embodiment, the updating of the basic NAV timer may be performed at a time of switching from the PCH to the NPCA PCH. In another embodiment, the updating of the basic NAV timer may be performed after switching from the PCH to the NPCA PCH.

[0196] Continuing with example 1600, after switching to the NPCA PCH, STA 1602 may access the NPCA PCH and transmit a frame 1610 to STA 1604. As shown in FIG. 16, frame 1610 may be transmitted via a bandwidth that comprises the NPCA PCH. For example, frame 1610 may be transmitted via the NPCH PCH and SCH2. In an embodiment, STA 1602 may transmit frame 1610 after switching to the NPCA PCH. Specifically, in example 1600, after instructing STA 1604 to switch to the NPCA PCH at time T, STA 1602 may expect that STA 1604 is ready / available to receive via the NPCA PCH after time T. STA 1602 may thus transmit frame 1610 at a transmission time based on T (e.g., immediately after T, after a random backoff from T, a SIFS after T, etc.). Frame 1610 may comprise an initial control frame (ICF), a request-to-send (RTS) frame, a multi-user (MU)-RTS frame, a buffer status report poll (BSRP) trigger frame, a block ack request (BAR) frame, a clear-to-send (CTS) frame, a block ack (BA) frame, an acknowledgment (Ack) frame, a buffer status report (BSR) frame, an initial control response frame (ICR), a control frame, a management frame, or an action frame, for example.

[0197] In an embodiment, STA 1604 may respond to frame 1610 from STA 1602 by transmitting a frame 1612 to STA 1602. Frame 1612 may comprise a clear-to-send (CTS) frame, a BlockAck (BA) frame, an acknowledgment (Ack) frame, a buffer status report (BSR) frame, an initial control response frame (ICR), a control frame, a management frame, or an action frame, for example. Subsequently, STA 1602 may transmit a frame 1614 to STA 1604. Frame 1614 may comprise a data frame, a management frame, or an action frame, for example. STA 1604 may respond to frame 1614 by transmitting a frame 1616 to STA 1602. Frame 1616 may comprise an immediate response frame, such as an Ack frame or a BA frame. As such, successful communication may occur between STAs 1602 and 1604 on the NPCA PCH after STA 1604 switches to the NPCA PCH after receiving frame 1608. Further, interference to the destination STA of PPDU 1606 may be minimized or reduced based on STA 1602 instructing STA 1604 to switch from the PCH to the NPCA PCH.PCT / US25 / 48151 26 September 2025 (26.09.2025)Docket No.: 24-3044 PCTSTAs 1602 and 1604 may be configured to finish communicating on the NPCA PCH and return to the PCH before an end of PPDU 1606 or by the end of OBSS NAV duration.

[0198] FIG. 17 shows an example 1700 that illustrates another example NPCA operation according to an embodiment. As shown in FIG. 17, example 1700 includes STAs 1702 and 1704. As discussed above for STAs 1502 and 1504 illustrated in FIG. 15, STAs 1702 and 1704 may belong to the same BSS, may each be an AP STA or a non-AP STA, and may both support NPCA operation. In an embodiment, STA 1702 may be an AP STA, and STA 1704 may be a non-AP STA associated with AP STA 1702. STA 1702 may be referred to as an NPCA AP. STA 1704 may be referred to as an NPCA STA. Like STAs 1502 and 1504 illustrated in FIG. 15, STAs 1702 and 1704 may each support PHYLEN NPCA operation and / or MOPLEN NPCA operation, as discussed above in relation to FIGS. 9-10, and STAs 1702 and 1704 may each switch from a PCH to an NPCA PCH based on satisfying either condition 1) or condition 2), described above in relation to FIGS. 9-10.

[0199] As shown in FIG. 17, different from examples 1500 and 1600 beginning with a transmission of a PPDU, example 1700 may begin with a transmission of a frame 1706. Frame 1706 may be transmitted by a station that belongs to an OBSS relative to the BSS of STAs 1702 and 1704 (e.g., STAs 1702 and 1704 be associated with a same BSS, while frame 1706 is transmitted by a STA associated with a different BSS). In an embodiment, frame 1706 may be transmitted by an OBSS AP. Frame 1706 may comprise a management frame, an action frame, a control frame, a quality of service (QoS) null frame, or a QoS data frame. In an embodiment, where frame 1706 is a management frame, frame 1706 may be a beacon frame or an action frame. Frame 1706 may comprise parameter 1607 of example 1600. That is, parameter 1607 may be transmitted in a separate frame (e.g., frame 1706) before transmitting a PPDU 1707.

[0200] Similar to parameter 1607 explained in example 1600, frame 1706 may comprise an accepted received interference level (ARIL) of a frame at the destination STA of a PPDU to be transmitted in the next frame by the OBSS AP (e.g., PPDU 1707), a transmit power level of PPDU 1707, a set of beamforming weights, or a location of the destination STA of PPDU 1707. This is discussed further with respect to parameter 1607, above, in relation to FIG. 16.

[0201] On receiving frame 1706, STA 1702 may determine what parameters to use in the transmitting of a frame 1708 for instructing STA 1704 to switch from the PCH to the NPCA PCH, during transmission of PPDU 1707, which may be an inter-BSS PPDU.

[0202] As shown in FIG. 17, example 1700 may continue with a transmission of PPDU 1707 on the PCH. PPDU 1707 may be transmitted by a station that belongs to an OBSS relative to the BSS of STAs 1702 and 1704 (e.g., STAs 1702 and 1704 be associated with a same BSS, while PPDU 1707 is transmitted by a STA associated with a different BSS).

[0203] In an embodiment, PPDU 1707 may be transmitted by an OBSS AP. In example 1700, PPDU 1707 may be a PPDU, similar to PPDU 1506, addressed to a destination STA associated with the OBSS AP. InPCT / US25 / 48151 26 September 2025 (26.09.2025)Docket No.: 24-3044 PCT an example, STA 1702 may be within the communication range of the station (e.g., the OBSS AP) that transmitted PPDU 1707. In an example, STA 1704 may be outside the communication range (e.g., the OBSS AP) of the station that transmitted PPDU 1707. In an embodiment, STA 1702 may receive PPDU 1707, but STA 1704 may not receive PPDU 1707. Operating on the PCH, STA 1702 may detect / sense the transmission of PPDU 1707 and begin to read / decode PPDU 1707.

[0204] Similar to STA 1502 illustrated in FIG. 15, STA 1702 may determine that PPDU 1707 is an inter-BSS PPDU. This is discussed further, above, in relation to FIG. 15. In addition to determining PPDU 1707 being an inter-BSS PPDU, similar to STA 1502 illustrated in FIG. 15, STA 1702 may obtain a value of the duration associated with PPDU 1707. This is also discussed further, above, in relation to FIG. 15. For example, STA 1702 may support PHYLEN NPCA operation and / or MOPLEN NPCA operation, as discussed above in relation to FIGS. 9-10, and may determine whether to switch from the PCH to the NPCA PCH based on satisfying either condition 1) or condition 2), described above in relation to FIGS. 9-10.

[0205] In an embodiment, before switching from the PCH to the NPCA PCH, STA 1702 may be configured to instruct its associated STAs to switch from the PCH to the NPCA PCH. As such, STAs that may not have received PPDU 1707 may also switch to the NPCA PCH based on receiving an instruction from STA 1702.

[0206] In another embodiment, STA 1702 may suggest / recommend to its associated STAs to switch from the PCH to the NPCA PCH, before STA 1702 switches from the PCH to the NPCA PCH. As such, STAs that may not have received PPDU 1707 may decide based on receiving a suggestion / recommendation from STA 1702. In an embodiment, STAs that may not have received PPDU 1707 may also switch to the NPCA PCH based on the suggestion / recommendation. In another embodiment, STAs that may not have received PPDU 1707 may prefer to stay on the PCH, despite the suggestion / recommendation.

[0207] In another embodiment, STA 1702 may be configured to inform / notify / announce to / report to its associated STAs, before STA 1702 switches from the PCH to the NPCA PCH, that STA 1702 is going to switch from the PCH to the NPCA PCH (based on STA 1702 detecting an inter-BSS PPDU). As such, STAs that may not have received PPDU 1707 may be aware that STA 1702 is going to switch from the PCH to the NPCA PCH. In a further embodiment, being informed by STA 1702, STAs that may not have received PPDU 1707 may also determine to switch to the NPCA PCH based on the information provided by STA 1702. In another further embodiment, despite being informed by STA 1702, STAs that may not have received PPDU 1707 may prefer to stay on the PCH.

[0208] In example 1700, STA 1702 may be configured to instruct / request its associated STAs to switch from the PCH to the NPCA PCH, before switching from the PCH to the NPCA PCH. While example 1700 illustrates STA 1702 instructing / requesting its associated STAs to switch from the PCH to the NPCA PCH, example 1700 may be readily extended to STA 1702 suggesting / recommending to its associated STAs to switch from the PCH to the NPCA PCH, or to STA 1702 informing / notifying / reporting / announcing to its associated STAs that STA 1702 is going to switch from the PCH to the NPCA PCH. For example, STA 1702 may supportPCT / US25 / 48151 26 September 2025 (26.09.2025)Docket No.: 24-3044 PCTPHYLEN NPCA operation and / or MOPLEN NPCA operation, as discussed above in relation to FIGS. 9-10, and may instruct / request / suggest / recommend / inform / notify / report / an nounce to its associated STAs to switch from the PCH to the NPCA PCH based on STA 1702 satisfying either condition 1) or condition 2), described above in relation to FIGS. 9-10.

[0209] Before switching from the PCH to the NPCA PCH, STA 1702 may be configured to instruct its associated STAs to switch from the PCH to the NPCA PCH. Similar to STA 1502 illustrated in FIG. 15, STA 1702 may determine whether STA 1704 is outside the communication range of PPDU 1707 as described further, above, in relation to FIG. 15.

[0210] In example 1700, STA 1702 may instruct STA 1704 to switch from the PCH to the NPCA PCH based on determining PPDU 1707 comprises an inter-BSS PPDU. For example, as illustrated in example 1700, after determining PPDU 1707 comprises the inter-BSS PPDU and obtaining a value of the duration associated with PPDU 1707, STA 1702 may transmit, via the PCH and during the duration associated with PPDU 1707, frame 1708 instructing STA 1704, associated with STA 1702, to switch from the PCH to the NPCA PCH. In an embodiment, the transmitting of frame 1708 may be based on the determining that PPDU1707 comprises the inter-BSS PPDU.

[0211] In an embodiment, like STA 1602 discussed above in relation to FIG. 16, STA 1702 may determine one or more of a transmit power level or beamforming weights for transmitting frame 1708, considering frame1706. In an embodiment, the transmitting of frame 1708 may comprise transmitting using a power level based on frame 1706, where frame 1706 comprises at least one of the ARIL of frame 1708 at the destination STA of PPDU 1707 or the transmit power level of PPDU 1707. In an embodiment, transmitting using a power level based on frame 1706, where frame 1706 comprises at least one of the ARIL of frame 1708 at the destination STA of PPDU 1707 or the transmit power level of PPDU 1707, may comprise transmitting frame 1708 using at least one of OBSS PD-based SR, PSR-based SR, or CSR. Each of these is discussed further, above, in relation to FIG. 16. In another embodiment, the transmitting of frame 1708 may comprise transmitting frame1708 using the beamforming weights. In an embodiment, transmitting frame 1708 using the beamforming weights may comprise transmitting using at least one of beamforming or coordinated beamforming. This is also discussed further, above, in relation to FIG. 16. As such, interference to the destination STA of PPDU1707, stemming from STA 1702 transmitting frame 1708, is minimized or avoided.

[0212] Similar to STA 1502 illustrated in FIG. 15, STA 1702 may not update a basic NAV timer associated with PPDU 1707. This allows STA 1702 transmit frame 1708 during the transmission of PPDU 1707. In another embodiment, STA 1702 may update a basic NAV timer and ignore the updated basic NAV timer for transmitting frame 1708. Alternatively, or in addition, the STA 1702 may update the basic NAV timer after transmitting frame 1708.

[0213] In an embodiment, frame 1708 may include a management frame, an action frame, a control frame, a quality of service (QoS) null frame, a QoS data frame, or any other suitable frame. In an example, framePCT / US25 / 48151 26 September 2025 (26.09.2025)Docket No.: 24-3044 PCT1708 may be a trigger frame (e.g., an MU-RTS trigger frame or another suitable trigger frame), and the instruction for STA 1704 to switch from the PCH to the NPCA PCH may be included in a common info field of the trigger frame (e.g., a common info field of a MU-RTS trigger frame). In an embodiment, frame 1708 may further comprise the duration associated with PPDU 1707.

[0214] After transmitting PPDU 1707, STA 1702 may switch from the PCH to the NPCA PCH. In an example, the switching may be at time T.

[0215] In example 1700, STA 1704 may receive from STA 1702, via the PCH and during the duration associated with PPDU 1707, frame 1708. Frame 1708 may be instructing STA 1704, associated with STA 1702, to switch from the PCH to the NPCA PCH.

[0216] In an embodiment, after receiving frame 1708, STA 1704 may switch from the PCH to the NPCA PCH. In an example, the switching may be at time T (e.g., the same switching time as STA 1702). Furthermore, STA 1704 may update the basic NAV timer with the duration associated with PPDU 1707. In an example, the basic NAV timer may be for the PCH. In an embodiment, the updating of the basic NAV timer may be performed before switching from the PCH to the NPCA PCH. In another embodiment, the updating of the basic NAV timer may be performed at a time of switching from the PCH to the NPCA PCH. In another embodiment, the updating of the basic NAV timer may be performed after switching from the PCH to the NPCA PCH.

[0217] Continuing with example 1700, after switching to the NPCA PCH, STA 1702 may access the NPCA PCH and transmit a frame 1710 to STA 1704. As shown in FIG. 17, frame 1710 may be transmitted via a bandwidth that comprises the NPCA PCH. For example, frame 1710 may be transmitted via the NPCH PCH and SCH2. In an embodiment, STA 1702 may transmit frame 1710 after switching to the NPCA PCH. Specifically, in example 1700, after instructing STA 1704 to switch to the NPCA PCH at time T, STA 1702 may expect that STA 1704 is ready / available to receive via the NPCA PCH after time T. STA 1702 may thus transmit frame 1710 at a transmission time based on T (e.g., immediately after T, after a random backoff from T, a SIFS after T, etc.). Frame 1710 may comprise an initial control frame (ICF), a request-to-send (RTS) frame, a multi-user (MU)-RTS frame, a buffer status report poll (BSRP) trigger frame, a block ack request (BAR) frame, a clear-to-send (CTS) frame, a block ack (BA) frame, an acknowledgment (Ack) frame, a buffer status report (BSR) frame, an initial control response frame (ICR), a control frame, a management frame, or an action frame, for example.

[0218] In an embodiment, STA 1704 may respond to frame 1710 from STA 1702 by transmitting a frame 1712 to STA 1702. Frame 1712 may comprise a clear-to-send (CTS) frame, a BlockAck (BA) frame, an acknowledgment (Ack) frame, a buffer status report (BSR) frame, an initial control response frame (ICR), a control frame, a management frame, or an action frame, for example. Subsequently, STA 1702 may transmit a frame 1714 to STA 1704. Frame 1714 may comprise a data frame, a management frame, or an action frame, for example. STA 1704 may respond to frame 1714 by transmitting a frame 1716 to STA 1702. FramePCT / US25 / 48151 26 September 2025 (26.09.2025)Docket No.: 24-3044 PCT1716 may comprise an immediate response frame, such as an Ack frame or a BA frame. As such, successful communication may occur between STAs 1702 and 1704 on the NPCA PCH after STA 1704 switches to the NPCA PCH after receiving frame 1708. Further, interference to the destination STA of PPDU 1707 may be minimized or reduced based on STA 1702 instructing STA 1704 to switch from the PCH to the NPCA PCH. STAs 1702 and 1704 may be configured to finish communicating on the NPCA PCH and return to the PCH before an end of PPDU 1707 or by the end of OBSS NAV duration.

[0219] FIG. 18 illustrates an example process 1800 according to an embodiment. Example process 1800 is provided for the purpose of illustration only and is not limiting of embodiments. Example process 1800 may be performed by a first access point (AP), such as STA 1502, STA 1602, or STA 1702, for example. The first AP may comprise an AP STA. As shown in FIG. 18, example process 1800 may include steps 1802, and 1804.

[0220] Step 1802 includes determining, by the first AP, that a PPDU being received via a PCH comprises an inter-BSS PPDU.

[0221] Step 1804 includes transmitting, via the PCH and during a duration associated with the PPDU, a frame instructing a STA, associated with the first AP, to switch from the PCH to an NPCA PCH.

[0222] In an embodiment, the transmitting of the frame is based on the determining that the PPDU comprises the inter-BSS PPDU.

[0223] In an embodiment, process 1800 may further comprise not updating a basic NAV timer with the duration associated with the PPDU. In an embodiment, not updating the basic NAV timer is based on the determining that the PPDU comprises the inter-BSS PPDU. In an embodiment, not updating the basic NAV timer comprises ignoring the duration associated with the PPDU. In another embodiment, not updating the basic NAV timer comprises not setting the basic NAV timer to the duration.

[0224] In an embodiment, process 1800 may further comprise updating a basic network allocation vector (NAV) timer with the duration associated with the PPDU. In an embodiment, process 1800 may further comprise ignoring the updated basic NAV timer for the transmitting of the frame. In another embodiment, the updating of the basic NAV timer is performed after the transmitting of the frame.

[0225] In an embodiment, process 1800 may further comprise obtaining, based on the PPDU, a value of the duration. In an embodiment, the obtaining, based on the PPDU, the value of duration comprises obtaining the value from a duration field of a PHY header of the PPDU. In another embodiment, the obtaining, based on the PPDU, the value of duration comprises obtaining the value from a duration field of a medium access control (MAC) header of the PPDU. In an embodiment, the determining that the PPDU comprises the inter- BSS PPDU comprises decoding a signal (SIG) field of the PPDU. In an embodiment, the PPDU comprises a preamble part (or PHY header), where the preamble part (or PHY header) comprises the SIG field. In an embodiment, the PPDU comprises an extremely high throughput (EHT) PPDU, an ultra-high reliability (UHR) PPDU, or a UHR+ PPDU, where the SIG field comprises a universal SIG (U-SIG) field of the PPDU. InPCT / US25 / 48151 26 September 2025 (26.09.2025)Docket No.: 24-3044 PCT another embodiment, the PPDU comprises a high efficiency (HE) PPDll, where the SIG field comprises an HE-SIG-A field of the PPDU. In an embodiment, the SIG field comprises a BSS color field set to a first BSS color different than a second BSS color of the first AP.

[0226] In an embodiment, the PPDU is transmitted by a second AP. In an embodiment, process 1800 may further comprise receiving, by the first AP from the second AP, a parameter for the transmitting of the frame. In an embodiment, the parameter comprises an accepted received interference level (ARIL) of the frame at a destination STA of the PPDU. In an embodiment, the parameter comprises a transmit power level of the PPDU.

[0227] In another embodiment, the transmitting of the frame comprises transmitting using a power level based on the parameter, where the parameter comprises at least one of an ARIL of the frame at a destination STA of the PPDU or a transmit power level of the PPDU.

[0228] In another embodiment, the parameter comprises a set of beamforming weights. In an embodiment, the transmitting of the frame comprises transmitting the frame using the beamforming weights.

[0229] In another embodiment, the parameter comprises a location of a destination STA of the PPDU.

[0230] In an embodiment, process 1800 may further comprise determining one or more of a transmit power level or beamforming weights.

[0231] In an embodiment, the frame comprises a management frame, an action frame, a control frame, a quality of service (QoS) null frame, or a QoS data frame.

[0232] In an embodiment, process 1800 may further comprise switching, by the first AP, from the PCH to the NPCA PCH, after transmitting the frame.

[0233] In an embodiment, a spatial reuse field of the PPDU is set to a first value that allows spatial reuse.

[0234] In an embodiment, process 1800 may further comprise determining whether the STA is outside a communication range of the PPDU, based on information received from the STA. In an embodiment, the information comprises a list of BSSs for which the STA is inside communication range. In another embodiment, the transmitting of the frame is based on the STA being outside the communication range.

[0235] In an embodiment, the frame further comprises the duration associated with the PPDU.

[0236] FIG. 19 illustrates another example process 1900 according to an embodiment. Example process 1900 is provided for the purpose of illustration only and is not limiting of embodiments. Example process 1900 may be performed by a station (STA), such as STA 1504, STA 1604, or STA 1704, for example. The first STA may comprise a non-AP STA. As shown in FIG. 19, example process 1900 may include step 1902.

[0237] Step 1902 includes receiving, by the STA from a first AP, via a PCH and during a duration associated with a PPDU being received by the first AP via the PCH, a frame instructing the STA, associated with the first AP, to switch from the PCH to an NPCA PCH.

[0238] In an embodiment, the PPDU comprises an inter-BSS PPDU.PCT / US25 / 48151 26 September 2025 (26.09.2025)Docket No.: 24-3044 PCT

[0239] In an embodiment, process 1900 may further comprise switching, by the STA, from the PCH to the NPCA PCH.

[0240] In an embodiment, the frame comprises a duration associated with the PPDU. In an embodiment, process 1900 may further comprise updating, by the STA, a basic NAV timer with the duration associated with the PPDU, wherein the basic NAV timer is for the PCH. In an embodiment, the updating of the basic NAV timer is performed before switching from the PCH to the NPCA PCH. In another embodiment, the updating of the basic NAV timer is performed at a time of switching from the PCH to the NPCA PCH. In another embodiment, the updating of the basic NAV timer is performed after switching from the PCH to the NPCA PCH.

[0241] In an embodiment, the frame comprises a management frame, an action frame, a control frame, a quality of service (QoS) null frame, or a QoS data frame.

[0242] In an embodiment, process 1900 may further comprise transmitting, by the STA to the first AP, information regarding whether the STA is outside a communication range of the PPDU. In an embodiment, the information comprises a list of BSSs for which the STA is inside communication range. In another embodiment, the STA receives the frame after the transmitting, by the STA to the first AP, the information.

[0243] FIG. 20 illustrates another example process 2000 according to an embodiment. Example process 2000 is provided for the purpose of illustration only and is not limiting of embodiments. Example process 2000 may be performed by a first access point (AP), such as the transmitting STA of PPDU 1506, PPDU 1606, and PPDU 1707, for example. The first AP may comprise an AP STA. As shown in FIG. 20, example process 2000 may include step 2002.

[0244] Step 2002 includes transmitting, by the first AP, via a PCH, one or more first frames comprising a PPDU addressed to a first STA associated with the first AP; and a parameter, for a second AP, for transmitting a second frame instructing a second STA, associated with the second AP, to switch from the PCH to an NPCA PCH.

[0245] In an embodiment, the parameter comprises an accepted received interference level (ARIL) of the second frame at the first STA. In an embodiment, the parameter comprises a transmit power level of the PPDU.

[0246] In another embodiment, the transmitting of the second frame comprises transmitting using a power level based on the parameter, where the parameter comprises at least one of an ARIL of the second frame at the first STA or a transmit power level of the PPDU.

[0247] In another embodiment, the parameter comprises a set of beamforming weights. In an embodiment, the transmitting of the second frame comprises transmitting the second frame using the beamforming weights.

[0248] In another embodiment, the parameter comprises a location of the first STA.

[0249] In an embodiment, a spatial reuse field of the PPDU is set to a first value that allows spatial reuse.PCT / US25 / 48151 26 September 2025 (26.09.2025)Docket No.: 24-3044 PCT

[0250] In an embodiment, the PPDU comprises the parameter. In another embodiment, the transmitting of the parameter is before the transmitting of the PPDU.

[0251] FIG. 21 illustrates an example process 2100 according to an embodiment. Example process 2100 is provided for the purpose of illustration only and is not limiting of embodiments. Example process 2100 may be performed by a first access point (AP), such as STA 1502, STA 1602, or STA 1702, for example. The first AP may comprise an AP STA. As shown in FIG. 21, example process 2100 may include steps 2102, and 2104.

[0252] Step 2102 includes determining, by the first AP, that a PPDU being received via a PCH comprises an inter-BSS PPDU.

[0253] Step 2104 includes not updating a basic network allocation vector (NAV) timer with a duration associated with the PPDU.

Claims

Docket No.: 24-3044PCTCLAIMSWhat is claimed is:

1. A method, comprising: determining, by an access point (AP), that a physical layer (PHY) protocol data unit (PPDU) being received via a primary channel (PCH) comprises an inter-basic service set (inter-BSS) PPDU; obtaining, based on the PPDU, a value of a duration associated with the PPDU; and based on the determining: not updating a basic network allocation vector (NAV) timer with the value of the duration; and transmitting, via the PCH and during the duration, a frame instructing a station (STA), associated with the AP, to switch from the PCH to a non-primary channel access (NPCA) PCH.

2. A method, comprising: determining, by a first access point (AP), that a physical layer (PHY) protocol data unit (PPDU) being received via a primary channel (PCH) comprises an inter-basic service set (inter-BSS) PPDU; and transmitting, via the PCH and during a duration associated with the PPDU, a frame instructing a station (STA), associated with the first AP, to switch from the PCH to a non-primary channel access (NPCA) PCH.

3. The method of claim 2, wherein the transmitting of the frame is based on the determining that the PPDU comprises the inter-BSS PPDU.

4. The method of any of claims 2-3, further comprising not updating a basic network allocation vector (NAV) timer with the duration associated with the PPDU.

5. The method of claim 4, wherein not updating the basic NAV timer is based on the determining that the PPDU comprises the inter-BSS PPDU.

6. The method of any of claims 4-5, wherein not updating the basic NAV timer comprises ignoring the duration associated with the PPDU.

7. The method of any of claims 4-5, wherein not updating the basic NAV timer comprises not setting the basic NAV timer to the duration.

8. The method of any of claims 2-3, further comprising updating a basic network allocation vector (NAV) timer with the duration associated with the PPDU.

9. The method of claim 8, further comprising ignoring the updated basic NAV timer for the transmitting of the frame.

10. The method of claim 8, wherein the updating of the basic NAV timer is performed after the transmitting of the frame.Docket No.: 24-3044PCT11. The method of any of claims 2-10, further comprising obtaining, based on the PPDU, a value of the duration.

12. The method of claim 11 , wherein the obtaining, based on the PPDU, the value of duration comprises obtaining the value from a duration field of a PHY header of the PPDU.

13. The method of claim 11 , wherein the obtaining, based on the PPDU, the value of duration comprises obtaining the value from a duration field of a medium access control (MAC) header of the PPDU.

14. The method of any of claims 2-13, wherein the determining that the PPDU comprises the inter-BSS PPDU comprises decoding a signal (SIG) field of the PPDU.

15. The method of claim 14, wherein the PPDU comprises a preamble part (or PHY header), and wherein the preamble part (or PHY header) comprises the SIG field.

16. The method of any of claims 14-15, wherein the PPDU comprises an extremely high throughput (EHT) PPDU, an ultra-high reliability (UHR) PPDU, or a UHR+ PPDU, and wherein the SIG field comprises a universal SIG (U-SIG) field of the PPDU.

17. The method of any of claims 14-15, wherein the PPDU comprises a high efficiency (HE) PPDU, and wherein the SIG field comprises an HE-SIG-A field of the PPDU.

18. The method of any of claims 14-17, wherein the SIG field comprises a BSS color field set to a first BSS color different than a second BSS color of the first AP.

19. The method of any of claims 2-18, wherein the PPDU is transmitted by a second AP.

20. The method of claim 19, further comprising receiving, by the first AP from the second AP, a parameter for the transmitting of the frame.21 . The method of claim 20, wherein the parameter comprises an accepted received interference level (ARIL) of the frame at a destination STA of the PPDU.

22. The method of any of claims 20-21 , wherein the parameter comprises a transmit power level of the PPDU.

23. The method of claim 20, wherein the transmitting of the frame comprises transmitting using a power level based on the parameter, and wherein the parameter comprises at least one of an ARIL of the frame at a destination STA of the PPDU or a transmit power level of the PPDU.

24. The method of claim 20, wherein the parameter comprises a set of beamforming weights.

25. The method of claim 24, wherein the transmitting of the frame comprises transmitting the frame using the beamforming weights.

26. The method of claim 20, wherein the parameter comprises a location of a destination STA of the PPDU.

27. The method of any of claims 20-26, further comprising determining one or more of a transmit power level or beamforming weights.

28. The method of any of claims 2-27, wherein the frame comprises a management frame, an action frame, a control frame, a quality of service (QoS) null frame, or a QoS data frame.Docket No.: 24-3044PCT29. The method of any of claims 2-28, further comprising switching, by the first AP, from the PCH to the NPCA PCH, after transmitting the frame.

30. The method of any of claims 2-29, wherein a spatial reuse field of the PPDU is set to a first value that allows spatial reuse.

31. The method of any of claims 2-30, further comprising determining whether the STA is outside a communication range of the PPDU, based on information received from the STA.

32. The method of claim 31 , wherein the information comprises a list of BSSs for which the STA is inside communication range.

33. The method of claim 31 , wherein the transmitting of the frame is based on the STA being outside the communication range.

34. The method of any of claims 2-33, wherein the frame further comprises the duration associated with the PPDU.

35. A method, comprising: determining, by an access point (AP), that a physical layer (PHY) protocol data unit (PPDU) being received via a primary channel (PCH) comprises an inter-basic service set (inter-BSS) PPDU; and not updating a basic network allocation vector (NAV) timer with a duration associated with the PPDU.

36. A method, comprising: receiving, by a station (STA) from a first access point (AP) a frame, wherein the frame is received via a primary channel (PCH) and during a duration associated with a physical layer (PHY) protocol data unit (PPDU) being received by the first AP via the PCH, wherein the PPDU comprises an inter-basic service set (inter-BSS) PPDU, and wherein the frame instructs the STA, associated with the first AP, to switch from the PCH to a non-primary channel access (NPCA) PCH; and switching, by the STA, from the PCH to the NPCA PCH.

37. A method, comprising: receiving, by a station (STA) from a first access point (AP), via a primary channel (PCH) and during a duration associated with a physical layer (PHY) protocol data unit (PPDU) being received by the first AP via the PCH, a frame instructing the STA, associated with the first AP, to switch from the PCH to a non-primary channel access (NPCA) PCH.

38. The method of claim 37, wherein the PPDU comprises an inter-basic service set (inter-BSS) PPDU.

39. The method of any of claims 37-38, further comprising switching, by the STA, from the PCH to the NPCA PCH.

40. The method of any of claims 37-39, wherein the frame comprises a duration associated with the PPDU.Docket No.: 24-3044PCT41. The method of claim 40, further comprising updating, by the STA, a basic network allocation vector (NAV) timer with the duration associated with the PPDU, wherein the basic NAV timer is for the PCH.

42. The method of claim 41 , wherein the updating of the basic NAV timer is performed before switching from the PCH to the NPCA PCH.

43. The method of claim 41 , wherein the updating of the basic NAV timer is performed at a time of switching from the PCH to the NPCA PCH.

44. The method of claim 41 , wherein the updating of the basic NAV timer is performed after switching from the PCH to the NPCA PCH.

45. The method of any of claims 37-44, wherein the frame comprises a management frame, an action frame, a control frame, a quality of service (QoS) null frame, or a QoS data frame.

46. The method of any of claims 37-45, further comprising transmitting, by the STA to the first AP, information regarding whether the STA is outside a communication range of the PPDU47. The method of claim 46, wherein the information comprises a list of BSSs for which the STA is inside communication range.

48. The method of claim 46, wherein the STA receives the frame after the transmitting, by the STA to the first AP, the information.

49. A method comprising: transmitting, by a first access point (AP), via a primary channel (PCH), one or more first frames comprising: a physical layer (PHY) protocol data unit (PPDU) addressed to a first station (STA) associated with the first AP; and a parameter, for a second AP, for transmitting a second frame instructing a second STA, associated with the second AP, to switch from the PCH to a non-primary channel access (NPCA) PCH.

50. The method of claim 49, wherein the parameter comprises an accepted received interference level (ARIL) of the second frame at the first STA.51 . The method of any of claims 49-50, wherein the parameter comprises a transmit power level of the PPDU.

52. The method of claim 49, wherein the transmitting of the second frame comprises transmitting using a power level based on the parameter, and wherein the parameter comprises at least one of an ARIL of the second frame at the first STA or a transmit power level of the PPDU.

53. The method of claim 49, wherein the parameter comprises a set of beamforming weights.

54. The method of claim 53, wherein the transmitting of the second frame comprises transmitting the second frame using the beamforming weights.

55. The method of claim 49, wherein the parameter comprises a location of the first STA.Docket No.: 24-3044PCT56. The method of any of claims 49-55, wherein a spatial reuse field of the PPDU is set to a first value that allows spatial reuse.

57. The method of any of claims 49-56, wherein the PPDU comprises the parameter.

58. The method of any of claims 49-57, wherein the transmitting of the parameter is before the transmitting of the PPDU.

59. A device comprising: one or more processors; and memory storing instructions that, when executed by the one or more processors, cause the device to perform a method according to any of claims 1-58.

60. A non-transitory computer-readable medium comprising instructions that, when executed by one or more processors, cause the one or more processors to perform a method according to any of claims 1-

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