Conditional non-primary channel access operation

Abstract

A station (STA) 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. Based on determining that the PPDU being received via the PCH comprises the inter-BSS PPDU, the STA switches from the PCH to a non-primary channel access (NPCA) PCH based on an intra-BSS network allocation vector (NAV) of the STA being equal to zero.

Description

Docket No.: 24-3053PCTTITLEConditional Non-Primary Channel Access Operation CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application No. 63 / 712,768, filed October 28, 2024, and No. 63 / 720,321 , filed November 14, 2024, all of 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) / Clear-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 illustrates a problem that may arise during NPCA operation.

[0015] FIG. 13 shows an example that illustrates an example NPCA operation according to an embodiment.

[0016] FIG. 14 shows an example that illustrates an example NPCA operation according to an embodiment.

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

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

[0019] FIG. 17 illustrates an example process according to an embodiment.

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

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

[0022] 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 canDocket No.: 24-3053PCT 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.

[0023] 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.

[0024] 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.

[0025] 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 employedDocket No.: 24-3053PCT 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.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] 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 thatDocket No.: 24-3053PCT 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.

[0030] FIG. 1 illustrates example wireless communication networks 100 in which embodiments of the present disclosure may be implemented.

[0031] 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.

[0032] 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 1 10-2 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.

[0033] 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).

[0034] 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.

[0035] 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 a 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).

[0036] 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.

[0037] 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 usedDocket No.: 24-3053PCT 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.

[0038] 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.

[0039] A frequency band may include one or more sub-bands or frequency channels. For example, PPDUs conforming to the IEEE 802.11 n, 802.11ac, 802.11 ax and / or 802.11 be 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.

[0040] FIG. 2 is a block diagram 200 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.

[0041] 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), aDocket No.: 24-3053PCT microcontroller, an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), a logic circuit, or a chipset, for example.

[0042] 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.

[0043] 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.

[0044] FIG. 3 illustrates an example format of a MAC frame 300. 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 300 using the frame check sequence (FCS) contained in the frame and may interpret certain fields from the MAC headers of all frames.

[0045] As shown in FIG. 3, a MAC frame 300 includes a MAC header, a variable length frame body, and a frame check sequence (FCS).

[0046] 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.

[0047] 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.

[0048] The protocol version subfield is invariant in size and placement across all revisions of the IEEE 802.1 1 standard. The value of the protocol version subfield is 0 for MAC frames.

[0049] 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 subtypeDocket No.: 24-3053PCT 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.

[0050] 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.

[0051] 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 (MMPDU) 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.

[0052] 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.

[0053] The power management subfield is used to indicate the power management mode of a STA.

[0054] 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.

[0055] The protected frame subfield is set to 1 if the frame body field contains information that has been processed by a cryptographic encapsulation algorithm.

[0056] The +HTC subfield indicates that the MAC frame 300 contains an HT control field.

[0057] 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.

[0058] There can be up to four address fields in the format of MAC frame 300. These 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.Docket No.: 24-3053PCT

[0059] 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.

[0060] 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.

[0061] 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. The control frame subtype for which HT control field is present is the control wrapper frame. A control frame that is described as +HTC (e.g., a request to send (RTS)+HTC, clear to send (CTS)+HTC, block acknowledgment (BlockAck)+HTC or block acknowledgment request (BlockAckReq)+HTC frame) implies the use of the control wrapper frame to carry that control frame.

[0062] 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.

[0063] 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.

[0064] FIG. 4 illustrates an example trigger frame 400. Trigger frame 400 may correspond to a basic trigger frame as defined in the existing IEEE 802.1 1 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.

[0065] 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.

[0066] 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.

[0067] 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, theDocket No.: 24-3053PCTDuration 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).

[0068] 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.

[0069] 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.

[0070] 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.

[0071] 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 SIPS (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 1 s.

[0072] 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.

[0073] 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 the 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 SIFS periods.Docket No.: 24-3053PCT

[0074] The one or more user info fields correspond respectively to the one or more STAs solicited by MU- 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.

[0075] 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”).

[0076] 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 802.1 1 standard draft “IEEE P802.1 1-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.

[0077] 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 / ID field. The Duration / ID field may be set to the time, in microseconds, required to transmit data frame 710, plus one CTS frame, plus one ACK frame (if required), plus three SIFS (Short Interframe Spacing) periods.

[0078] 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 toDocket No.: 24-3053PCTRTS 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-S1 G 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 S1 G STA, 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.

[0079] 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.

[0080] 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.

[0081] 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.

[0082] 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 802.1 1 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).

[0083] 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.

[0084] 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.Docket No.: 24-3053PCT

[0085] 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.

[0086] 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.

[0087] 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.

[0088] 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 trigger frame 808 initiated a TXOP, AP 802 shall invoke its backoff procedure at the PHY-RXEND. indication primitive.

[0089] 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 transmissionDocket No.: 24-3053PCT of CTS frames 810 and 812, respectively, at the SIFS time boundary after an end of a received PPDU comprising MU-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 802.1 1 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.

[0090] 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.

[0091] 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.

[0092] 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.

[0093] 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.

[0094] 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 and via which the AP transmits management frames), the STA may have one or more secondary channels considered as NPCA primary 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.Docket No.: 24-3053PCT

[0095] FIG. 9 shows an example 900 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 .

[0096] In an implementation, as shown in FIG. 10 illustrating an example 1000, 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).

[0097] 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.

[0098] 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”).

[0099] 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 of 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 throughoutDocket No.: 24-3053PCT 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.

[0100] FIG. 11 shows an example 1 100 that illustrates an NPCA operation. As shown in FIG. 11 , example 1 100 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).

[0101] Example 1100 may begin with the AP transmitting a frame 1 102 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 1 102 may be a management frame, such as a beacon frame, for example.

[0102] 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 1 104 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 1 104 on the PCH. Frame 1104 may indicate a transmission (of one or more frames including frame 1104) on the PCH. A duration of the transmission on the PCH may be provided by a duration field of frame 1 104, a transmission opportunity (TXOP) duration field of an inter-basic service set (inter-BSS) PPDU comprising frame 1 104, or a length field of the inter-BSS PPDU. The AP and STA may set their NAVs for the PCH based on the duration of the OBSS transmission on the PCH (hereinafter, OBSS NAV duration or OBSS TXOP duration).

[0103] 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 T1 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, by time T2, as shown in example 1 100.Docket No.: 24-3053PCT

[0104] 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 1 102). In example 1 100, 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 1 106 on the NPCA PCH. In an 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.

[0105] FIG. 12 illustrates an example 1200 of a problem that may arise during NPCA operation. As shown in FIG. 12, example 1200 includes an AP 1202, a STA 1206, and an OBSS STA 1208. STA 1206, and another STA 1204 (not illustrated) may be associated with AP 1202 and belong to a BSS. AP 1202 and STA 1206 may both support NPCA operation and may operate over a plurality of channels, including a primary channel (PCH), an NPCA primary channel (NPCA PCH), and a first secondary channel (SCH1). As illustrated, OBSS STA 1208 belongs to an OBSS relative to the BSS that includes AP 1202 and STAs 1204 and 1206. OBSS STA 1208 may comprise an AP STA or a non-AP STA.

[0106] Example 1200 may begin with AP 1202 transmitting a frame 1210 on the PCH . AP 1202 may transmit frame 1210 using EDCA. AP 1202 may obtain a TXOP. Frame 1210 may indicate a first duration within the TXOP. A value of the first duration may be used by STAs associated with AP 1202, such as STA 1204 and STA 1206, to set a duration of an intra-BSS NAV. In an example, the value of the first duration may be larger than zero. Frame 1210 may comprise a CTS-to-self frame.

[0107] AP 1202 may exchange frames with STA 1204 within a period 1220. STA 1204 may receive frame 1210 while operating in the PCH (not illustrated in FIG. 12).

[0108] As shown in FIG. 12, STA 1206 also receives frame 1210 while operating in the PCH during a period 1220. During period 1220, STA 1206 may perform carrier sensing. STA 1206 may set its intra-BSS NAV based on the value of the first duration indicated by frame 1210. As shown in FIG. 12, the first duration may be associated with a period 1222. For example, the first duration may be the period 1222.

[0109] As shown in FIG. 12, AP 1202 transmits a PPDU 1212 (e.g., to STA 1204) within a period 1220. In an implementation, AP 1202 may receive a BA (not illustrated in FIG. 12) from STA 1204 in response to PPDU 1212.Docket No.: 24-3053PCT

[0110] Subsequently, while AP 1202, STA 1204, and STA 1206 operate on the PCH, OBSS STA 1208 may begin an OBSS transmission 1214, on the PCH, during a period 1224. For example, period 1224 may begin at a time T1 , as shown in FIG 12.

[0111] In an example, AP 1202 does not hear OBSS transmission 1214. For example, AP 1202 may not detect OBSS transmission 1214 while receiving the BA from STA 1204 during period 1224. In another example, OBSS STA 1208 may be hidden from AP 1202 and / or STA 1204.

[0112] STA 1206, by contrast, may detect OBSS transmission 1214 on the PCH. In an implementation, STA 1206 may be configured to set a NAV associated with the PCH based on receiving OBSS transmission 1214 on the PCH. OBSS transmission 1214 may indicate a transmission (e.g., of one or more frames) on the PCH. A duration of the transmission on the PCH may, for example, be provided by a duration field of a frame associated with OBSS transmission 1214, a TXOP duration field of an inter-BSS PPDU associated with OBSS transmission 1214, or a length field of the inter-BSS PPDU. STA 1206 may set its basic NAV for the PCH based on the duration of OBSS transmission 1214 on the PCH (hereinafter, OBSS NAV duration or OBSS TXOP duration).

[0113] In accordance with NPCA operation, on receiving an inter-BSS PPDU and obtaining the OBSS NAV duration, STA 1206 may be configured to switch to the NPCA PCH for the OBSS NAV duration. In an example, STA 1206 may switch to the NPCA PCH at time T1 as shown in FIG. 12. Here, time T1 may correspond to the time for switching to NPCA PCH after obtaining the OBSS NAV duration. As shown in FIG. 12, the OBSS NAV duration may be associated with period 1224.

[0114] STA 1206 may be configured to intend 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, by time T2, as shown in FIG. 12.

[0115] A problem, however, may arise in the above-described NPCA operation when AP 1202 does not detect OBSS transmission 1214. As shown in FIG. 12, AP 1202 continues to operate in the PCH without knowledge that STA 1206 switches to the NPCA PCH during period 1224. As such, AP 1202 may transmit to STA 1206 a PPDU 1216 via the PCH, within period 1224 as shown in FIG. 12. As a result, STA 1206 fails to receive PPDU 1216 via the PCH because STA 1206 has switched to the NPCA PCH. As such, channel resources (e.g., PCH resources), as well as AP resources, used to transmit the PPDU to the STA, may be wasted.

[0116] Embodiments of the present disclosure, as further described below, address the above-described problem of existing technologies. In an aspect, a STA may determine that a PPDU being received via a PCH comprises an inter-basic service set (inter-BSS) PPDU. In an embodiment, based on the PPDU and a first value of an intra-BSS network allocation vector (NAV) of the STA, the STA may switch from the PCH to a non-primary channel access (NPCA) PCH. The first value of the intra-BSS NAV is lower than or equal to a first threshold. In an embodiment, based on determining that the PPDU being received via the PCH comprisesDocket No.: 24-3053PCT the inter-BSS PPDU, the STA may switch from the PCH to a non-primary channel access (NPCA) PCH based on an intra-BSS NAV of the STA being equal to zero. In another aspect, a STA may switch from the PCH to a NPCA PCH in response to: a PPDU being received via a PCH comprises an inter-BSS PPDU; and an intra- BSS NAV of the STA being equal to zero. In an embodiment, the STA may receive via the PCH, a first frame indicating a second duration used by the STA to set / update the intra-BSS NAV. Based on the PPDU and a second value of an intra-BSS NAV of the STA, the STA may not switch from the PCH to the NPCA PCH. In an embodiment, the second value of the intra-BSS NAV may be set to the second duration. The second value of the intra-BSS NAV may be non-zero. The second value of the intra-BSS NAV may be higher than a second threshold. In an embodiment, using a value of an intra-BSS NAV in determining whether to switch from the PCH to the NPCA PCH may help avoid loss of PCH resources (and AP resources) by avoiding transmitting frames on the PCH to a STA that has switched to the NPCA PCH.

[0117] FIG. 13 shows an example 1300 that illustrates an example NPCA operation according to an embodiment. As shown in FIG. 13, example 1300 includes an AP 1302, a STA 1306, and an OBSS STA 1308. STA 1306, and another STA 1304 (not illustrated) may be associated with AP 1302 and belong to a BSS. In an example, AP 1302 and STA 1306 may both support NPCA operation and may operate over a plurality of channels, including a primary channel (PCH), an NPCA primary channel (NPCA PCH), and a first secondary channel (SCH1 ). As illustrated, OBSS STA 1308 belongs to an OBSS relative to the BSS that includes AP 1302 and STAs 1304 and 1306. OBSS STA 1308 may comprise an AP STA or a non-AP STA. In an example, one or more of AP 1302, STAs 1304 and 1306, or OBSS STA 1308, may comprise a multilink device (MLD) STA.

[0118] Example 1300 may begin with AP 1302 transmitting a frame 1310 on the PCH. In an example, AP 1302 may transmit frame 1310 using EDCA. In an embodiment, AP 1302 may obtain a TXOP. In an embodiment, frame 1310 may indicate a first duration within the TXOP. In an embodiment, AP 1302 intends to transmit a PPDU 1312 to STA 1304 via the PCH. In an embodiment, AP 1302 intends to transmit a PPDU 1316 to STA 1306 via the PCH. In an example, the first duration may comprise a duration of transmitting PPDU 1312 and a duration of transmitting PPDU 1316. For example, the first duration may be associated with a period 1322 (e.g., the first duration may be the period 1322). In an example, period 1322 may begin at the end of frame 1310 and may end at the end of the TXOP.

[0119] In an embodiment, a value of the first duration may be used by STAs associated with AP 1302, such as STA 1304 and STA 1306, to set a duration of an intra-BSS NAV. In an embodiment, the value of the first duration may be larger than zero. Further, in an embodiment, the value of the first duration may be equal to a value of the TXOP.

[0120] In an embodiment, frame 1310 may comprise a control frame. In an example, the control frame may comprise a CTS-to-self frame.Docket No.: 24-3053PCT

[0121] AP 1302 may exchange frames with STA 1304 within a period 1320. STA 1304 may receive frame 1310 while operating in the PCH (not illustrated in FIG. 13).

[0122] As shown in FIG. 13, STA 1306 also receives frame 1310 while operating in the PCH during period 1320. During period 1320, STA 1306 may perform carrier sensing. STA 1306 may be configured to set its intra-BSS NAV associated with the PCH based on the value of the first duration. For example, STA 1306 may set the intra-BSS NAV to the duration of period 1322.

[0123] As shown in FIG. 13, AP 1302 may transmit a PPDU 1312 (e.g., to STA 1304) within a period 1320. In an example, PPDU 1312 may indicate a second duration within the TXOP. In an example, the second duration may comprise a duration of transmitting PPDU 1316. In an example, the second duration may be associated with a period 1324 (e.g., the second duration may be period 1324). For example, period 1324 may begin at the end of PPDU 1312, and may end at the end of the TXOP. In an embodiment, a value of the second duration may be used by STAs associated with AP 1302, such as STA 1304 and STA 1306, to update the duration of the intra-BSS NAV. In an implementation, AP may receive a BA (not illustrated in FIG. 13) from STA 1304 in response to PPDU 1312.

[0124] As shown in FIG. 13, STA 1306 may detect PPDU 1312 while operating in the PCH during period 1320. STA 1306 may be configured to update its intra-BSS NAV associated with the PCH based on the value of the second duration. For example, STA 1306 may update the intra-BSS NAV to the duration of period 1324.

[0125] Subsequently, while AP 1302, STA 1304, and STA 1306 operate on the PCH, OBSS STA 1308 may begin a transmission of a PPDU 1314 on the PCH. As shown in FIG. 13, OBSS STA 1308 may transmit PPDU 1314 during a period 1326 beginning at a time T1.

[0126] In an example, AP 1302 does not hear PPDU 1314. For example, AP 1302 may not detect PPDU 1314 while receiving the BA from STA 1304 during period 1326. In another example, OBSS STA 1308 may be hidden from AP 1302 and / or STA 1304.

[0127] STA 1306, by contrast, may detect PPDU 1314 on the PCH. In an embodiment, STA 1306 may determine that PPDU 1314 being received via the PCH comprises an inter-BSS PPDU.

[0128] In an embodiment, STA 1306 may be configured to set a basic NAV associated with the PCH based on receiving PPDU 1314 on the PCH. PPDU 1314 may indicate a transmission (e.g., of one or more frames including PPDU 1314) on the PCH. A duration of the transmission on the PCH may, for example, be provided by a duration field of the frame carried in PPDU 1314, a TXOP duration field of an inter-BSS PPDU (e g., PPDU 1314), or a length field of the inter-BSS PPDU. STA 1306 may set its basic NAV for the PCH based on the duration of the OBSS transmission on the PCH (referred to herein as the OBSS NAV duration or OBSS TXOP duration).

[0129] In an embodiment, at the beginning of period 1326 (e.g., T1 ), a count-down value of the intra-BSS NAV duration associated with the PCH of STA 1306 corresponds to the second duration associated withDocket No.: 24-3053PCT period 1324, minus a short interframe spacing (SI FS). In an embodiment, the value of the intra-BSS NAV of STA 1306 is non-zero. In an embodiment, the value of the intra-BSS NAV of STA 1306 is larger than a first value. In an implementation, the first value may comprise a SIFS.

[0130] In an embodiment, based on PPDU 1314 and the value of the intra-BSS NAV of STA 1306 (e.g. a value that is non-zero or larger than the first value), STA 1306 does not switch from the PCH to the NPCA PCH. In an embodiment, STA 1306 not switching from the PCH to a NPCA PCH may comprise disabling the NPCA. For example, STA 1306 may disable the NPCA during the intra-BSS NAV, associated with the PCH, of STA 1306. In another example, STA 1306 may disable the NPCA during the basic NAV, associated with the PCH, of STA 1306. In an embodiment, STA 1306 not switching from the PCH to a NPCA PCH may comprise STA 1306 remaining to operate in the PCH.

[0131] As shown in FIG. 13, AP 1302 transmits PPDU 1316 via the PCH. In an embodiment, STA 1306 receives PPDU 1316 via the PCH while hearing the PPDU 1314 during period 1326. In an example, STA 1306 transmits a BA frame 1318 to AP 1302 in response to PPDU 1316. In an embodiment, STA 1306 determining not to switch from the PCH to the NPCA PCH in this circumstance (e.g., based on the value of the intra-BSS NAV of STA 1306 being non-zero or larger than a threshold) may help avoid loss of PCH resources (and AP resources) by avoiding transmitting frames on the PCH to a STA that has switched to the NPCA PCH.

[0132] In another embodiment (not illustrated in FIG. 13), AP 1302 may not intend to transmit PPDU 1316 during period 1324. In an example, the first duration indicated in frame 1310 or the second duration indicated in PPDU 1312 may not comprise the duration of transmitting PPDU 1316. In an embodiment, STA 1306 may be configured to count-down its intra-BSS NAV to zero, or less than a second value (e.g., a SIFS), at T1 In an embodiment, STA 1306 may detect PPDU 1314 on the PCH. In an embodiment, STA 1306 may determine PPDU 1314 being received via the PCH comprises an inter-BSS PPDU. In an implementation, STA 1306 may be configured to set a basic NAV associated with the PCH based on receiving PPDU 1314 on the PCH. For example, the basic NAV may comprise a duration of period 1326. In an embodiment, based on PPDU 1314 and the second value of the intra-BSS NAV of STA 1306, STA 1306 switches from the PCH to the NPCA PCH. In an embodiment, STA 1306 determining to switch from the PCH to the NPCA PCH in this circumstance (e.g., based on the value of the intra-BSS NAV of STA 1306 being zero or smaller than a threshold) may improve efficiency and throughput by making use of the NPCA PCH.

[0133] FIG. 14 shows an example 1400 that illustrates an example NPCA operation according to an embodiment. As shown in FIG. 14, example 1400 includes an AP 1402, a STA 1406, and an OBSS STA 1408. STA 1406, and another STA 1404 (not illustrated) may be associated with AP 1402 and belong to a BSS. In an example, AP 1402 and STA 1406 may both support NPCA operation and may operate over a plurality of channels, including a primary channel (PCH), an NPCA primary channel (NPCA PCH), and a first secondary channel (SCH1 ). As illustrated, OBSS STA 1408 belongs to an OBSS relative to the BSS thatDocket No.: 24-3053PCT includes AP 1402 and STAs 1404 and 1406. OBSS STA 1408 may comprise an AP STA or a non-AP STA. In an example, one or more of AP 1402, STAs 1404 and 1406, or OBSS STA 1408, may comprise a multilink device (MLD) STA.

[0134] Example 1400 may begin with AP 1402 transmitting a frame 1410 on the PCH. In an example, AP 1402 may transmit frame 1410 using EDCA. In an embodiment, AP 1402 may obtain a TXOP. In an embodiment, frame 1410 may indicate a first duration within the TXOP. In an embodiment, AP 1402 intends to transmit a PPDU 1412 to STA 1404 via the PCH. In an embodiment, AP 1402 intends to transmit a PPDU 1416 to STA 1406 via the PCH. In an example, the first duration may comprise a duration of transmitting PPDU 1412 and a duration of transmitting PPDU 1416. For example, the first duration may be associated with a period 1422 (e.g., the first duration may be the period 1422). In an example, period 1422 may begin at the end of frame 1410 and may end at the end of the TXOP. In an embodiment, the first duration may be used by STAs associated with AP 1402, such as STA 1404 and STA 1406, to set respective intra-BSS NAVs.

[0135] In an embodiment, frame 1410 may comprise a control frame. In an example, the control frame may comprise a CTS-to-self frame.

[0136] AP 1402 may exchange frames with STA 1404 within a period of 1420. STA 1404 may receive frame 1410 while operating in the PCH (not illustrated in FIG. 14).

[0137] As shown in FIG. 14, STA 1406 receives frame 1410 while operating in the PCH during a period 1420. During period 1420, STA 1406 may perform carrier sensing. STA 1406 may set an intra-BSS NAV associated with the PCH to a first value. In an embodiment, the first value of the intra-BSS NAV of STA 1406 may be set to the first duration. The first duration may comprise the duration of period 1422. In an embodiment, the first value of the intra-BSS NAV of STA 1406 may be non-zero. In an implementation, the first value of the intra-BSS NAV may be equal to a duration of the TXOP.

[0138] As shown in FIG. 14, AP 1402 may transmit a PPDU 1412 (e.g., to STA 1404) within a period 1420. In an example, PPDU 1412 may indicate a second duration within the TXOP. In an example, the second duration may comprise a duration of transmitting PPDU 1416. In an example, the second duration may be associated with a period 1424 (e.g., the second duration may be period 1424). For example, period 1424 may begin at the end of PPDU 1412, and may end at the end of the TXOP. In an embodiment, the second duration may be used by STAs associated with AP 1402, such as STA 1404 and STA 1406, to set / update respective intra-BSS NAVs. In an implementation, AP may receive a BA (not illustrated in FIG. 14) from STA 1404 in response to PPDU 1412.

[0139] As shown in FIG. 14, STA 1406 may detect PPDU 1412 while operating in the PCH during period 1420. STA 1406 may set / update the intra-BSS NAV associated with the PCH to a second value. In an embodiment, the second value of the intra-BSS NAV of STA 1406 may be set to the second duration (e.g., the duration of period 1424).Docket No.: 24-3053PCT

[0140] Subsequently, while the AP 1402, STA 1404, and STA 1406 operate on the PCH, OBSS STA 1408 may begin a transmission of a PPDU 1414 on the PCH. As shown in FIG. 14, OBSS STA 1408 may transmit PPDU 1414 during a period 1426 beginning at a time T1.

[0141] In an example, AP 1402 does not hear PPDU 1414. For example, AP 1402 may not detect PPDU 1414 while receiving the BA from STA 1404 during period 1426. In another example, OBSS STA 1408 may be hidden from AP 1402 and / or STA 1204.

[0142] STA 1406, by contrast, may detect PPDU 1414 on the PCH. In an embodiment, STA 1406 may determine that PPDU 1414 being received via the PCH comprises an inter-BSS PPDU.

[0143] In an embodiment, STA 1406 may be configured to set a basic NAV associated with the PCH based on receiving PPDU 1414 on the PCH. PPDU 1414 may indicate a transmission (e.g., of one or more frames including PPDU 1414) on the PCH. A duration of the transmission on the PCH may, for example, be provided by a duration field of the frame carried in PPDU 1414, a TXOP duration field of an inter-BSS PPDU (e g., PPDU 1414), or a length field of the inter-BSS PPDU. STA 1406 may set its basic NAV for the PCH based on the duration of the OBSS transmission on the PCH (referred to herein as the OBSS NAV duration or OBSS TXOP duration). For example, STA 1406 may set a value of the basic NAV associated with the PCH to a duration of period 1426.

[0144] In an embodiment, the intra-BSS NAV of STA 1406 may count down over time. In an example, STA 1406 may update the intra-BSS NAV associated with the PCH to a third value. In an embodiment, the third value of the intra-BSS NAV of STA 1406 may be set to a third duration at T1. As shown in FIG. 14, the third duration may comprise a duration of a period 1428 between T1 and a time T2. In an embodiment, the third value of intra-BSS NAV of STA 1406 may be non-zero. In an embodiment, the third value of intra-BSS NAV of STA 1406 may be higher than a first threshold. In an implementation, the first threshold may comprise a SIFS.

[0145] In an embodiment, based on PPDU 1414 and the third value of the intra-BSS NAV of STA 1406, STA 1406 does not switch from the PCH to the NPCA PCH. In an embodiment, STA 1406 not switching from the PCH to the NPCA PCH may comprise disabling the NPCA. In an embodiment, STA 1406 may disable the NPCA during period 1428, related to the intra-BSS NAV, associated with the PCH, of STA 1406. In another embodiment, STA 1406 may disable the NPCA during period 1426, related to the basic NAV, associated with the PCH, of STA 1406. In an embodiment, STA 1406 not switching from the PCH to the NPCA PCH may comprise STA 1406 remaining to operate in the PCH.

[0146] As shown in FIG. 14, AP 1402 transmits PPDU 1416 via the PCH. In an embodiment, STA 1406 receives PPDU 1416 via the PCH while hearing PPDU 1414 during period 1426. In an example, STA 1406 transmits a BA frame 1418 to AP 1402 in response to PPDU 1416. In an embodiment, STA 1406 determining not to switch from the PCH to the NPCA PCH in this circumstance (e.g., based on the value of the intra-BSSDocket No.: 24-3053PCTNAV of STA 1406 being non-zero or larger than a threshold) may help avoid loss of PCH resources (and AP resources) by avoiding transmitting frames on the PCH to a STA that has switched to the NPCA PCH.

[0147] As shown in FIG. 14, the TXOP ends at T2. In an example, period 1422 or period 1424 ends at T2. In an example, OBSS STA 1408 may continue transmitting PPDU 1414 during a period 1430 beginning at T2. In an embodiment, STA 1406 may be configured to set / update the intra-BSS NAV to a fourth value at T2. In an embodiment, the fourth value of the intra-BSS NAV of STA 1406 may be zero. In an embodiment, the fourth value of the intra-BSS NAV of STA 1406 may be lower than a second threshold. In an implementation, the second threshold may comprise a SIFS.

[0148] In an embodiment, STA 1406 detects the PPDU 1414 on the PCH at T2. In an embodiment, STA 1406 determines PPDU 1414 being received via the PCH comprises the inter-BSS PPDU. In an implementation, STA 1406 may be configured to set / update the basic NAV associated with the PCH based on receiving PPDU 1414 on the PCH at T2. For example, STA 1406 may set / update a value of the basic NAV to a duration of period 1430. In an embodiment, based on PPDU 1414 and the fourth value of the intra- BSS NAV of STA 1406 (e.g., based on the fourth value being zero or smaller than a second threshold), STA 1406 switches from the PCH to the NPCA PCH at T2. In an embodiment, STA 1406 determining to switch from the PCH to the NPCA PCH in this circumstance (e.g., based on the value of the intra-BSS NAV of STA 1406 being zero or smaller than a threshold) may improve efficiency and throughput by making use of the NPCA PCH.

[0149] FIG. 15 shows an example 1500 that illustrates an example NPCA operation according to an embodiment. As shown in FIG. 15, example 1500 includes an AP 1502, a STA 1506, and an OBSS STA 1508. STA 1506, and another STA 1504 (not illustrated) may be associated with AP 1502 and belong to a BSS. In an example, AP 1502 and STA 1506 may both support NPCA operation and may operate over a plurality of channels, including a primary channel (PCH), an NPCA primary channel (NPCA PCH), and a first secondary channel (SCH1 ). As illustrated, OBSS STA 1508 belongs to an OBSS relative to the BSS that includes AP 1502 and STAs 1504 and 1506. OBSS STA 1508 may comprise an AP STA or a non-AP STA. In an example, one or more of AP 1502, STAs 1504 and 1506, or OBSS STA 1508, may comprise a multilink device (MLD) STA.

[0150] Example 1500 may begin with AP 1502 transmitting a frame 1510 on the PCH. In an example, AP 1502 may transmit frame 1510 using EDCA. In an embodiment, AP 1502 may obtain a TXOP. In an embodiment, frame 1510 may indicate a first duration within the TXOP. In an embodiment, AP 1502 intends to transmit a PPDU 1512 to STA 1504 via the PCH. For example, the first duration may comprise a duration of transmitting PPDU 1512 and receiving a BA (not illustrated in FIG. 15). In an embodiment, AP 1502 intends to transmit a PPDU 1516 to STA 1506 via the PCH. For example, the first duration may further comprise a duration of transmitting PPDU 1516. In an example, the first duration may be associated with a period 1522. For example, period 1522 may begin at the end of frame 1510 and may end at the end of the TXOP. In anDocket No.: 24-3053PCT embodiment, the first duration may be used by STAs associated with AP 1502, such as STA 1504 and STA 1506, to set respective intra-BSS NAVs.

[0151] In an embodiment, frame 1510 may comprise a control frame. In an example, the control frame may comprise a CTS-to-self frame.

[0152] AP 1502 may exchange frames with STA 1504 within a period of 1520. STA 1504 may receive frame 1510 while operating in the PCH (not illustrated in FIG. 15).

[0153] As shown in FIG. 15, STA 1506 receives frame 1510 while operating in the PCH during a period 1520. During period 1520, STA 1506 may perform carrier sensing. STA 1506 may set an intra-BSS NAV associated with the PCH to a first value. In an embodiment, the first value of the intra-BSS NAV of STA 1506 may be set to the first duration. The first duration may comprise the duration of period 1522. In an embodiment, the first value of the intra-BSS NAV of STA 1506 may be non-zero. In an implementation, the first value of the intra-BSS NAV may be equal to a duration of the TXOP.

[0154] As shown in FIG. 15, AP 1502 may transmit a PPDU 1512 (e.g., to STA 1504) within a period 1520. In an example, PPDU 1512 may indicate a second duration within the TXOP. In an example, the second duration may comprise a duration of transmitting PPDU 1516. In an example, the second duration may be associated with a period 1524 (e.g., the second duration may be the period 1524). For example, period 1524 may begin at the end of PPDU 1512 and may end at the end of the TXOP. In an embodiment, a value of the second duration may be used by STAs associated with AP 1502, such as STA 1504 and STA 1506, to set / update respective intra-BSS NAVs. In an implementation, AP may receive a BA (not illustrated in FIG. 15) from STA 1504 in response to PPDU 1512.

[0155] As shown in FIG 15, STA 1506 may detect PPDU 1512 while operating in the PCH during period 1520. STA 1506 may set / update the intra-BSS NAV associated with the PCH to a second value. In an embodiment, the second value of the intra-BSS NAV of STA 1506 may be set to the second duration (e.g., the duration of period 1524). In an embodiment, the second value of the intra-BSS NAV of STA 1506 may be non-zero.

[0156] Subsequently, while AP 1502, STA 1504, and STA 1506 operate on the PCH, OBSS STA 1508 may begin a transmission of a PPDU 1530 on the PCH. As shown in FIG. 15, OBSS STA 1508 may transmit PPDU 1530 during a period 1526 beginning at a time T1.

[0157] In an example, AP 1502 does not hear PPDU 1530. For example, AP 1502 may not detect PPDU 1530 while receiving the BA from STA 1504 during period 1526. In another example, OBSS STA 1508 may be hidden from AP 1502 and / or STA 1204.

[0158] STA 1506, by contrast, may detect PPDU 1530 on the PCH. In an embodiment, STA 1506 may determine that PPDU 1530 being received via the PCH comprises an inter-basic service set (inter-BSS) PPDU.Docket No.: 24-3053PCT

[0159] In an embodiment, STA 1506 may be configured to set a basic NAV associated with the PCH based on receiving PPDU 1530 on the PCH. PPDU 1530 may indicate a transmission (e.g., of one or more frames including PPDU 1530) on the PCH. A duration of the transmission on the PCH may, for example, be provided by a duration field of the frame carried in PPDU 1530, a TXOP duration field of an inter-BSS PPDU (e.g., PPDU 1530), or a length field of the inter-BSS PPDU. STA 1506 may set its basic NAV for the PCH based on the duration of the OBSS transmission on the PCH (referred to herein as the OBSS NAV duration or OBSS TXOP duration). For example, STA 1506 may set a value of the basic NAV associated with the PCH to a duration of period 1526.

[0160] In an embodiment, the intra-BSS NAV of STA 1506 may count down over time. In an example, STA 1506 may update the intra-BSS NAV associated with the PCH to a third value. In an embodiment, the third value of the intra-BSS NAV of STA 1506 may be set to a third duration at T1. As shown in FIG. 15, the third duration may comprise a duration of a period 1528 between T1 and a time T2. In an embodiment, the third value of intra-BSS NAV of STA 1506 may be non-zero. In an embodiment, the third value of intra-BSS NAV of STA 1506 may be higher than a first threshold. In an implementation, the first threshold may comprise a SIFS.

[0161] In an embodiment, based on PPDU 1530 and the third value of intra-BSS NAV of STA 1506, STA 1506 does not switch from the PCH to the NPCA PCH. In an embodiment, STA 1506 not switching from the PCH to the NPCA PCH may comprise STA 1506 remaining to operate in the PCH. In an embodiment, STA 1506 not switching from the PCH to the NPCA PCH may comprise STA 1506 disabling the NPCA. In an embodiment, STA 1506 may disable the NPCA during period 1528, related to the intra-BSS NAV, associated with the PCH, of STA 1506 In another embodiment, STA 1506 may disable the NPCA during period 1526, related to the basic NAV, associated with the PCH, of STA 1506.

[0162] In an embodiment, AP 1502 may transmit a frame 1514 to truncate the TXOP during period 1526. In an implementation, a duration field of frame 1514 may be set to zero. Thus, AP 1502 may shorten the TXOP to a first TXOP ending by the end of frame 1514. In an embodiment, STA 1506 may set / update its intra-BSS NAV to zero based on frame 1514.

[0163] In an example, AP 1502 may obtain a second TXOP using EDCA after the first TXOP. As shown in FIG. 15, AP 1502 transmits PPDU 1516 via the PCH after transmitting frame 1514. In an embodiment, STA 1506 receives PPDU 1516 via the PCH while hearing the PPDU 1530 during period 1526. In an example, STA 1506 transmits a BA frame 1518 to AP 1502 in response to PPDU 1516. In an embodiment, STA 1506 determining not to switch from the PCH to the NPCA PCH in this circumstance (e.g., based on the value of the intra-BSS NAV of STA 1506 being non-zero or larger than a threshold) may help avoid loss of PCH resources (and AP resources) by avoiding transmitting frames on the PCH to a STA that has switched to the NPCA PCH.Docket No.: 24-3053PCT

[0164] FIG. 16 shows an example 1600 that illustrates an example NPCA operation according to an embodiment. As shown in FIG. 16, example 1600 includes an AP 1602, a STA 1606, and an OBSS STA 1608. STA 1606, and another STA 1604 (not illustrated) may be associated with AP 1602 and belong to a BSS. In an example, AP 1602, STA 1604, and STA 1606 may support NPCA operation and may operate over a plurality of channels, including a primary channel (PCH), an NPCA primary channel (NPCA PCH), and a first secondary channel (SCH1 ). OBSS STA 1608 may belong to an OBSS relative to the BSS that includes AP 1602 and STAs 1604 and 1606. OBSS STA 1608 may comprise an AP STA or a non-AP STA. In an example, one or more of AP 1602, STAs 1604 and 1606, or OBSS STA 1608, may comprise a multi-link device (MLD) STA.

[0165] Example 1600 may begin with STA 1604 transmitting a PPDU 1610 to AP 1602 on the PCH. In an example, STA 1604 may transmit PPDU 1610 using EDCA. In an embodiment, STA 1604 may obtain a first TXOP. In an embodiment, PPDU 1610 may indicate a first duration within the first TXOP. In an example, the first duration may comprise a duration of transmitting PPDU 1610 and receiving a BA (not illustrated in FIG. 16) in response to PPDU 1610. In an example, the first duration may be associated with a period 1620. For example, period 1620 may begin at the beginning of PPDU 1610 and may end at the end of the first TXOP. In an embodiment, a value of the first duration may be used by STA 1606 to set an intra-BSS NAV.

[0166] As shown in FIG. 16, STA 1606 may detect PPDU 1610 while operating in the PCH during period 1620. During period 1620, STA 1606 may perform carrier sensing. STA 1606 may be configured to set an intra-BSS NAV associated with the PCH to a first value. In an embodiment, the first value of the intra-BSS NAV of STA 1606 may be set to the first duration. For example, the first duration may be a period 1620. In an embodiment, the first value of the intra-BSS NAV of STA 1606 may be non-zero. In an implementation, the first value of the intra-BSS NAV of STA 1606 may be equal to a duration of the first TXOP.

[0167] Subsequently, while the AP 1602 and STAs 1604 and 1606 operate on the PCH, OBSS STA 1608 may begin a transmission of a PPDU 1614 on the PCH. As shown in FIG. 16, OBSS STA 1608 may transmit PPDU 1614 during a period 1624 beginning at a time T1.

[0168] In an example, AP 1602 does not hear PPDU 1614. For example, AP 1602 may not detect PPDU 1614 while transmitting the BA to STA 1604 within period 1622. As another example, STA 1604 may not hear PPDU 1614. For example, STA 1604 may not detect PPDU 1614 while receiving the BA from AP 1602 within period 1622. In another example, OBSS STA 1608 may be hidden from AP 1602 and / or STA 1204.

[0169] STA 1606, by contrast, may detect PPDU 1614 on the PCH. In an embodiment, STA 1606 may determine that PPDU 1614 being received via the PCH comprises an inter-BSS PPDU.

[0170] In an implementation, STA 1606 may be configured to set a basic NAV associated with the PCH based on receiving PPDU 1614 on the PCH. PPDU 1614 may indicate a transmission (e.g., of one or more frames including PPDU 1614) on the PCH. A duration of the transmission on the PCH may, for example, be provided by a duration field of the frame carried in PPDU 1614, a TXOP duration field of an inter-BSS PPDUDocket No.: 24-3053PCT(e.g PPDU 1614), or a length field of the inter-BSS PPDU. STA 1606 may set its basic NAV for the PCH based on the duration of the OBSS transmission on the PCH (referred to herein as the OBSS NAV duration or OBSS TXOP duration). For example, STA 1606 may set a value of the basic NAV associated with the PCH to a duration of period 1624.

[0171] As shown in FIG. 16, STA 1604 may continue transmitting PPDU 1610 within a period 1622 beginning at T1 . In an example, STA 1604 may receive from AP 1602 a BA (not illustrated in FIG. 16) in response to PPDU 1610 within period 1622. In an example, period 1620 and period 1624 may be overlapping. As shown in FIG. 16, the overlapping between period 1624 and period 1620 may correspond to period 1622.

[0172] In an embodiment, the intra-BSS NAV of STA 1606 may count down over time. In an example, STA 1606 may update the intra-BSS NAV associated with the PCH to a second value. In an embodiment, the second value of the intra-BSS NAV of STA 1606 may be set to a second duration at T1 . In an example, the second duration may comprise a duration of a period 1622. In an embodiment, the second value of the intra- BSS NAV of STA 1606 is non-zero. In an embodiment, the second value of intra-BSS NAV of STA 1606 is higher than a first threshold. In an implementation, the first threshold may comprise a SIFS.

[0173] In an embodiment, based on PPDU 1614 and the second value of intra-BSS NAV of STA 1606, STA 1606 does not switch from the PCH to the NPCA PCH. In an example, the second value of intra-BSS NAV of STA 1606 may be set to the duration of period 1622. In an embodiment, STA 1606 not switching from the PCH to the NPCA PCH may comprise STA 1606 remaining to operate in the PCH. In an embodiment, STA 1606 not switching from the PCH to the NPCA PCH may comprise disabling / disactivating the NPCA. In an example, STA 1606 may disable the NPCA during period 1622, related to the intra-BSS NAV, associated with the PCH, of STA 1606. In another example, STA 1606 may disable the NPCA during period 1624, related to the basic NAV, associated with the PCH, of STA 1606.

[0174] After receiving PPDU 1610 from STA 1604, AP 1602 may perform EDCA via the PCH to obtain a second TXOP. In an example, AP 1602 may transmit a PPDU 1616 to STA 1606 via the PCH within the second TXOP. In an embodiment, PPDU 1616 may indicate a third duration used by STA 1606 to set / update the intra-BSS NAV. As shown in FIG. 16, STA 1606 may receive PPDU 1616 after detecting the OBSS transmission of PPDU 1614 via the PCH. STA 1606 may transmit a BA 1618 to AP 1602 via the PCH in response to PPDU 1616 within the second TOXP. In an embodiment, STA 1606 determining not to switch from the PCH to the NPCA PCH in this circumstance (e.g., based on the value of the intra-BSS NAV of STA 1606 being non-zero or larger than a threshold) may help avoid loss of PCH resources (and AP resources) by avoiding transmitting frames on the PCH to a STA that has switched to the NPCA PCH.

[0175] FIG. 17 illustrates an example process 1700 according to an embodiment. Example process 1700 is provided for the purpose of illustration only and is not limiting of embodiments. Example process 1700 may be performed by a station (STA), such as STA 1306, STA 1406, STA 1506, and STA 1606, for example. InDocket No.: 24-3053PCT an example, the STA may comprise a non-AP STA. As shown in FIG. 17, example process 1700 may include steps 1702, and 1704.

[0176] Step 1702 includes determining, by a station (STA), that a PPDU being received via a primary channel (PCH) comprises an inter-basic service set (inter-BSS) PPDU.

[0177] Step 1704 includes based on the PPDU and a value of an intra-BSS network allocation vector (NAV) of the STA, switching, by the STA, from the PCH to a non-primary channel access (NPCA) PCH.

[0178] In an embodiment, the STA sets / updates the intra-BSS NAV.

[0179] In an embodiment, the intra-BSS NAV counts down over time.

[0180] In an embodiment, the value of the intra-BSS NAV is lower than or equal to a first threshold.

[0181] In an embodiment, the value of the intra-BSS NAV is equal to zero.

[0182] In an embodiment, the PPDU indicates a first duration used by the STA to set / update a basic NAV of the STA.

[0183] In an embodiment, the intra BSS NAV or the basic NAV is associated with the PCH.

[0184] In an embodiment, process 1700 further comprises: receiving, by the STA and via the PCH, a first frame indicating a second duration used by the STA to set / update the intra-BSS NAV.

[0185] In an embodiment, the first duration for the basic NAV and the second duration for the intra-BSS NAV are overlapping.

[0186] In an embodiment, the first duration for the basic NAV or the second duration for the intra-BSS NAV is within a transmission opportunity (TXOP) obtained by a second STA.

[0187] In an embodiment, the first frame initiates the TXOP on the PCH.

[0188] In an embodiment, the second STA transmits to a third STA the first frame.

[0189] In an embodiment, a third STA transmits to the second STA the first frame.

[0190] In an embodiment, the second STA comprises an AP STA.

[0191] In an embodiment, the third STA comprises a non-AP STA.

[0192] In an embodiment, process 1700 further comprises: based on a second inter-BSS PPDU received via the PCH and a second value of an intra-BSS NAV of the STA, not switching, by the STA, from the PCH to the NPCA PCH.

[0193] In an embodiment, the second value of the intra-BSS NAV is set to the second duration.

[0194] In an embodiment, the second value of the intra-BSS NAV is non-zero.

[0195] In an embodiment, the second value of the intra-BSS NAV is higher than a second threshold.

[0196] In an embodiment, not switching from the PCH to the NPCA PCH comprises remaining to operate in the PCH.

[0197] In an embodiment, not switching from the PCH to the NPCA PCH comprises disabling / deactivating an NPCA operation.Docket No.: 24-3053PCT

[0198] In an embodiment, disabling the NPCA occurs during the first duration related to the basic NAV of the STA.

[0199] In an embodiment, disabling the NPCA occurs during the second duration related to the intra-BSS NAV of the STA.

[0200] In an embodiment, process 1700 further comprises: receiving, by the STA and via the PCH, a second PPDU comprising an intra-BSS PPDU during the second duration.

[0201] In another embodiment, a STA may perform a process comprising: switching, by the STA, from the PCH to a NPCA PCH in response to: a PPDU being received via a PCH comprising an inter-BSS PPDU; and an intra-BSS NAV of the STA being equal to zero. The process may be performed by the STA, such as STA 1306, STA 1406, STA 1506, and STA 1606, for example. In an example, the STA may comprise a non-AP STA.

[0202] In another embodiment, a STA may perform a process comprising: determining, by the STA, that a PPDU being received via a PCH comprises an inter-BSS PPDU; and switching, by the STA, from the PCH to a NPCA PCH based on the PPDU and on condition that an intra-BSS NAV of the STA is lower than or equal to a first value. The process may be performed by the STA, such as STA 1306, STA 1406, STA 1506, and STA 1606, for example. The STA may comprise a non-AP STA.

[0203] 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 station (STA), such as STA 1306, STA 1406, STA 1506, and STA 1606, for example. In an example, the STA may comprise a non-AP STA. As shown in FIG. 18, example process 1800 may include steps 1802, and 1804.

[0204] Step 1802 includes determining, by a station (STA), that a PPDU being received via a primary channel (PCH) comprises an inter-basic service set (inter-BSS) PPDU.

[0205] Step 1804 includes remaining, by the STA, on the PCH based on the PPDU and on condition that an intra-BSS network allocation vector (NAV) of the STA is greater than or equal to a first value.

[0206] In an embodiment, the remaining, by the STA, on the PCH is on condition that the intra-BSS NAV of the STA is greater than a threshold.

[0207] In an embodiment, the threshold is zero.

[0208] In an embodiment, remaining, by the STA, on the PCH comprises determining not to switch from the PCH to a non-primary channel access (NPCA) PCH.

[0209] In an embodiment, remaining, by the STA, on the PCH comprises disabling / deactivating an NPCA operation.

[0210] In an embodiment, the PPDU indicates a first duration used by the STA to set / update a basic NAV of the STA.Docket No.: 24-3053PCT

[0211] In an embodiment, disabling the NPCA occurs during the first duration related to the basic NAV of the STA.

[0212] In an embodiment, disabling the NPCA occurs during a second duration related to the intra-BSS NAV of the STA.

[0213] In an embodiment, process 1800 further comprises: receiving, by the STA and via the PCH, a second PPDU comprising an intra-BSS PPDU during a third duration related to the intra-BSS NAV of the STA.

[0214] FIG. 19 illustrates an 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 first station (STA). The first STA may comprise an AP STA, such as AP 1302, AP 1402, and AP 1502, for example. The first STA may also comprise a non-AP STA, such as STA 1306, STA 1406, STA 1506, STA 1604, and STA 1606, for example. As shown in FIG. 19, example process 1900 may include steps 1902, and 1904.

[0215] Step 1902 includes transmitting, by a first station (STA) and via a primary channel (PCH), a first frame indicating a first duration used by a second STA to set / update an intra-basic service set (BSS) network allocation vector (NAV).

[0216] Step 1904 includes receiving, by the first STA from the second STA, a second frame, via the PCH, after the second STA receives via the PCH an inter-basic service set (inter-BSS) PPDU with the intra-BSS NAV set to a value higher than a threshold.

[0217] In an embodiment, the first STA owns a transmission opportunity (TXOP).

[0218] In an embodiment, the first STA comprises an AP STA.

[0219] In an embodiment, process 1900 further comprises: transmitting, by the first STA to the second STA via the PCH, a PPDU during the first duration.

[0220] In an embodiment, the second frame is addressed to the first STA.

[0221] In an embodiment, the first STA comprises a non-AP STA.

[0222] In an embodiment, process 1900 further comprises: transmitting, by the first STA to a third STA via the PCH, a second PPDU during the first duration.

[0223] In an embodiment, the second frame is addressed to the third STA.

[0224] In an embodiment, a STA (e.g., an AP or non-AP STA) described in any of the embodiments above may further perform one or more of the NPCA operations described herein below. As would be understood by a person of skill in the art based on the teachings, any of the NPCA operations described below may be combined with the procedures / operations described above. For example, a STA (e.g., an AP or non-AP STA) described above in relation to FIGS. 13-19 may switch to the NPCA primary channel for NPCA operation if either condition 1) or 2), described below, is met.

[0225] Hereinafter, a STA that supports NPCA operation is called an NPCA STA. An AP that supports NPCA operation is called an NPCA AP. A non-AP NPCA STA may set an NPCA Supported field of a UHR MACDocket No.: 24-3053PCTCapabilities Information field of a UHR 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.

[0226] 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.

[0227] 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.

[0228] In an implementation, an NPCA AP with a value (e.g., dotH HEPSROption 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.

[0229] 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 .

[0230] 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-OFDMA 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.Docket No.: 24-3053PCTAn 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.

[0231] 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.

[0232] 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 OMP Request frames.

[0233] 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.

[0234] 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.

[0235] 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 exceptDocket No.: 24-3053PCT that AIFSN[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 AIFSN[AC] values from the dot11 MUEDCATable.

[0236] 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.

[0237] 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 / UHRPPDU 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:1) 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 or 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:Docket No.: 24-3053PCT(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_DUR 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.

[0238] 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 PHY-CCA.indication(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.

[0239] 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 PHY-Docket No.: 24-3053PCTRXSTART. indication primitives associated with the received PPDU from the value of RXTIME of the received PPDU.

[0240] 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.

[0241] 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.Otherwise, it is set to the value in the Duration / ID 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.

[0242] 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 NPCADocket No.: 24-3053PCTNHT 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 O, 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 QSRC[AC], CW[AC] and the backoff counter for each EDCAF. 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_NPCAx(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) above.6) 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) is operating in DPS mode.Docket No.: 24-3053PCT 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 IGF conforms to the DUO mode rules.7) An NPCA AP that transmits a Trigger 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. 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.1 1) 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.

[0243] 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.

[0244] 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.

Claims

Docket No.: 24-3053PCTCLAIMS1 . A method comprising: determining, by a station (STA), 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 based on determining that the PPDU being received via the PCH comprises the inter-BSS PPDU, switching, by the STA, from the PCH to a non-primary channel access (NPCA) PCH based on an intra-BSS network allocation vector (NAV) of the STA being equal to zero.

2. A method comprising: determining, by a station (STA), 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 based on the PPDU and a first value of an intra-BSS network allocation vector (NAV) of the STA, switching, by the STA, from the PCH to a non-primary channel access (NPCA) PCH.

3. The method of claim 2, wherein the STA sets / updates the intra-BSS NAV.

4. The method of any of claims 2-3, wherein the intra-BSS NAV counts down over time.

5. The method of any of claims 2-4, wherein the first value of the intra-BSS NAV is lower than or equal to a first threshold.

6. The method of claim 5, wherein the first value of the intra-BSS NAV is equal to zero.

7. The method of any of claims 2-6, wherein the PPDU indicates a first duration used by the STA to set / update a basic NAV of the STA.

8. The method of claim 7, wherein the intra-BSS NAV or the basic NAV is associated with the PCH.

9. The method of any of claims 7-8, further comprising: receiving, by the STA and via the PCH, a first frame indicating a second duration used by the STA to set / update the intra-BSS NAV.

10. The method of claim 9, wherein the first duration for the basic NAV and the second duration for the intra-BSS NAV are overlapping.11 . The method of any of claims 9-10, wherein the first duration for the basic NAV or the second duration for the intra-BSS NAV is within a transmission opportunity (TXOP) obtained by a second STA.

12. The method of claim 11 , wherein the first frame initiates the TXOP on the PCH.

13. The method of any of claims 11 -12, wherein the second STA transmits to a third STA the first frame.

14. The method of any of claims 11 -12, wherein a third STA transmits to the second STA the first frame.

15. The method of any of claims 11 -14, wherein the second STA comprises an AP STA.

16. The method of any of claims 14-15, wherein the third STA comprises a non-AP STA.

17. The method of any of claims 9-16, further comprising: based on a second inter-BSS PPDU received via the PCH and a second value of an intra-BSS NAV of the STA, not switching, by the STA, from the PCH to the NPCA PCH.Docket No.: 24-3053PCT18. The method of claim 17, wherein the second value of the intra-BSS NAV is set to the second duration.

19. The method of any of claims 17-18, wherein the second value of the intra-BSS NAV is non-zero.

20. The method of any of claims 17-19, wherein the second value of the intra-BSS NAV is higher than a second threshold.

21. The method of any of claims 17-20, wherein not switching, from the PCH to the NPCA PCH comprises remaining to operate in the PCH.

22. The method of any of claims 17-21 , wherein not switching, from the PCH to the NPCA PCH comprises disabling / deactivating an NPCA operation.

23. The method of claim 22, wherein disabling the NPCA occurs during the first duration related to the basic NAV of the STA.

24. The method of claim 22, wherein disabling the NPCA occurs during the second duration related to the intra-BSS NAV of the STA.

25. The method of any of claims 17-24, further comprising: receiving, by the STA and via the PCH, a second PPDU comprising an intra-BSS PPDU during the second duration.

26. A method comprising: switching, by a station (STA), from a primary channel (PCH) to a non-primary channel access (NPCA) PCH in response to: a PPDU being received via a primary channel (PCH) comprising an inter-basic service set(inter-BSS) PPDU; and an intra-BSS NAV of the STA being equal to zero.

27. A method comprising: determining, by a station (STA), that a PPDU being received via a primary channel (PCH) comprises an inter-basic service set (inter-BSS) PPDU; and switching, by the STA, from the PCH to a non-primary channel access (NPCA) PCH based on the PPDU and on condition that an intra-BSS network allocation vector (NAV) of the STA is lower than or equal to a first value.

28. A method comprising: determining, by a station (STA), 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 determining that the PPDU being received via the PCH comprises the inter-BSS PPDU and remaining, by the STA, on the PCH based on an intra-BSS network allocation vector (NAV) of the STA being greater than zero.

29. A method comprising:Docket No.: 24-3053PCT determining, by a station (STA), 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 remaining, by the STA, on the PCH based on the PPDU and on condition that an intra-BSS network allocation vector (NAV) of the STA is greater than or equal to a first value.

30. The method of claim 29, wherein the remaining, by the STA, on the PCH is on condition that the intra- BSS NAV of the STA is greater than a threshold.31 . The method of claim 30, wherein the threshold is zero.

32. The method of any of claims 29-31 , wherein remaining, by the STA, on the PCH comprises determining not to switch from the PCH to a non-primary channel access (NPCA) PCH.

33. The method of any of claims 29-32, wherein remaining, by the STA, on the PCH comprises disabling / deactivating an NPCA operation.

34. The method of claim 33, wherein the PPDU indicates a first duration used by the STA to set / update a basic NAV of the STA.

35. The method of claim 34, wherein disabling the NPCA occurs during the first duration related to the basic NAV of the STA.

36. The method of any of claim 33, wherein disabling the NPCA occurs during a second duration related to the intra-BSS NAV of the STA.

37. The method of any of claims 29-36, further comprising: receiving, by the STA and via the PCH, a second PPDU comprising an intra-BSS PPDU during a third duration related to the intra-BSS NAV of the STA.

38. A method comprising: transmitting, by a first station (STA) and via a primary channel (PCH), a first frame indicating a first duration used by a second STA to set / update an intra-basic service set (BSS) network allocation vector (NAV); and receiving, by the first STA from the second STA, a second frame, via the PCH, after the second STA receives via the PCH an inter-basic service set (inter-BSS) physical layer (PHY) protocol data unit (PPDU) with the intra-BSS NAV set to a value higher than a threshold.

39. The method of claim 38, wherein the first STA owns a transmission opportunity (TXOP).

40. The method of any of claims 38-39, wherein the first STA comprises an AP STA.41 . The method of claim 40, further comprising: transmitting, by the first STA to the second STA via the PCH, a first PPDU during the first duration.

42. The method of claim 41 , wherein the second frame is addressed to the first STA.

43. The method of any of claims 38-39, wherein the first STA comprises a non-AP STA.

44. The method of claim 43, further comprising: transmitting, by the first STA to a third STA via the PCH, a second PPDU during the first duration.Docket No.: 24-3053PCT45. The method of claim 44, wherein the second frame is addressed to the third STA.

46. 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 1-45.

47. 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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