Frame-size based non-primary channel access (NPCA) operation

Abstract

A station determines that a physical layer protocol data unit (PPDU) being received via a primary channel (PCH) comprises an inter-basic service set (inter-BSS) PPDU. The station decodes a delimiter of a medium access protocol (MAC) protocol data unit (MPDU) of the PPDU to determine a length of the MPDU. Based on the length of the MPDU being larger than a threshold, the station switches from the PCH to a non-primary channel access (NPCA) PCH and communicates with another station on the NPCA PCH.

Description

Docket No.: 24-3041 PCTTITLEFRAME-SIZE BASED NON-PRIMARY CHANNEL ACCESS (NPCA) OPERATION CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application No. 63 / 696,899, filed September20, 2024, which is hereby incorporated by reference in its entirety.BRIEF DESCRIPTION OF THE DRAWINGS

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

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

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

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

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

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

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

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

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

[0011] FIG. 9 illustrates an example aggregate MAC protocol data unit (MPDU) format.

[0012] FIG. 10 is an example that illustrates non-primary channel access (NPCA) operation.

[0013] FIG. 11 illustrates virtual and physical carrier sense (CS) functions associated with primary and secondary channels for NPCA operation and non-NPCA operation.

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

[0015] FIG. 13 illustrates an inefficiency that may arise in the NPCA operation of FIG. 12.

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

[0017] FIG. 15 shows another example of the example NPCA operation illustrated in FIG. 14.

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

[0019] FIG. 17 shows an example that illustrates an example frame exchange according to an embodiment.

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

[0021] FIG. 19 illustrates another example process according to an embodiment.DETAILED DESCRIPTIONDocket No.: 24-3041 PCT

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

[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 suitableDocket No.: 24-3041 PCT possibilities that may, or may not, be employed to one or more of the various embodiments. The phrase "in response to" (or equally “in response at least to”) is indicative that the phrase following the phrase “in response to” is an example of one of a multitude of suitable possibilities that may, or may not, be employed to one or more of the various embodiments. The phrase “depending on” (or equally “depending at least to”) is indicative that the phrase following the phrase “depending on" is an example of one of a multitude of suitable possibilities that may, or may not, be employed to one or more of the various embodiments. The phrase “employing / using” (or equally “employing / using at least”) is indicative that the phrase following the phrase “employing / using” is an example of one of a multitude of suitable possibilities that may, or may not, be employed to one or more of the various embodiments.

[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 softwareDocket No.: 24-3041 PCT routine written in a computer language configured to be executed by a hardware machine (such as C, C++, Fortran, Java, Basic, Matlab or the like) or a modeling / simulation program such as Simulink, Stateflow, GNU Octave, or LabVIEWMathScript. It may be possible to implement modules using physical hardware that incorporates discrete or programmable analog, digital and / or quantum hardware. Examples of programmable hardware comprise: computers, microcontrollers, microprocessors, application-specific integrated circuits (ASICs); field programmable gate arrays (FPGAs); and complex programmable logic devices (CPLDs). Computers, microcontrollers, and microprocessors are programmed using languages such as assembly, C, C++, or the like. FPGAs, ASICs and CPLDs are often programmed using hardware description languages (HDL) such as VHSIC hardware description language (VHDL) or Verilog that configure connections between internal hardware modules with lesser functionality on a programmable device. The mentioned technologies are often used in combination to achieve the result of a functional module.

[0030] FIG. 1 illustrates example wireless communication networks 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) 1 10 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 doesDocket No.: 24-3041 PCT 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 used among the APs and the non-AP stations (STAs). The STA may also be referred to using various other terms, including mobile terminal, wireless device, wireless transmit / receive unit (WTRU), user equipment (UE), mobile station (MS), mobile subscriber unit, or user. For example, the term "user” may be used to denote a STA participating in uplink Multi-user Multiple Input, Multiple Output (MU MIMO) and / or uplink Orthogonal Frequency Division Multiple Access (OFDMA) transmission.

[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, 802.1 1ac, 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 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.Docket No.: 24-3041 PCT

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

[0045] As shown in FIG. 3, a MAC frame 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. BitsDocket No.: 24-3041 PCT within the subtype subfield are used to indicate a specific modification of the basic data frame (subtype 0). For example, in data frames, the most significant bit (MSB) of the subtype subfield, bit 7 (B7) of the frame control field, is defined as the QoS subfield. When the QoS subfield is set to 1 , it indicates a QoS data frame, which is a data frame that contains a QoS control field in its MAC header. The second MSB of the subtype field, bit 6 (B6) of the frame control field, when set to 1 in data subtypes, indicates a data frame that contain no frame body field.

[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 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] Up to four address fields may be present in the MAC frame format. The address fields are used to indicate the basic service set identifier (BSSID), source address (SA), destination address (DA), transmitting address (TA), and receiving address (RA). Certain frames may not contain some of the address fields. Certain address field usage may be specified by the relative position of the address field (1-4) within the MAC header,Docket No.: 24-3041 PCT 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.

[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.

[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.: 24-3041 PCTDuration 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.: 24-3041 PCT

[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.: 24-3041 PCTRTS 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.: 24-3041 PCT

[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.: 24-3041 PCT 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] FIG. 9 illustrates an example aggregate MPDU (A-MPDU) 900. As shown in FIG. 9, example A- MPDU 900 includes a sequence of one or more A-MPDU subframes (e.g., A-MPDU subframe 1 , A-MPDU subframe 2, . . . , A-MPDU subframe n) and an end of frame (EOF) Padding field. As shown, an A-MPDU subframe includes an MPDU delimiter optionally followed by an MPDU. Each nonfinal A-MPDU subframe in an A-MPDU includes padding octets appended to make the A-MPDU subframe a multiple of 4 octets in length.Docket No.: 24-3041 PCT

[0095] The purpose of the MPDU delimiter is to locate the MPDUs within the A-MPDU. The MPDU delimiter includes an EOF / Tag field, a Reserved field, an MPDU length field, a CRC field, and a Delimiter Signature field. The EOF / Tag field

[0096] The EOF / Tag field provides an end of frame indication if the MPDU Length field is 0. Specifically, the EOF / Tag field is set to 1 in an A-MPDU subframe that has 0 in the MPDU Length field and that is used to pad the A-MPDU in a Very High Throughput (VHT), High Efficiency (HE) PPDU, or Extremely High Throughput (EHT) PPDU. The EOF / Tag field is also set to 1 in the MPDU delimiter of an S-MPDU (Single MPDU). The EOF / Tag field provides a tagged / untagged indication if the MPDU Length field is nonzero. Specifically, the EOF / Tag field is set to 1 in an MPDU delimiter preceding a QoS Data frame or Management frame soliciting an Ack frame or Per AID TID Info field with the Ack Type field set to 1 in a multi-STA BlockAck frame in a response that is contained in an ack-enabled multi-TID A-MPDU and ack-enabled single-TID A- MPDU. The EOT / Tag field is set to 0 otherwise.

[0097] The MPDU length field indicates the length of the MPDU that follows the MPDU delimiter in octets. The MPDU length field is set to 0 is no MPDU is present following the MPDU delimiter in the A-MPDU subframe. An A-MPDU subframe with 0 in the MPDU length field is used to meet the minimum MPDU start spacing requirement and also to pad the A-MPDU to fill the available octets in a VHT or HE PPDU.

[0098] The CRC field provides an 8-bit CRC of the preceding 16 bits (the EOF / Tag field, the Reserved field, and the MPDU length field). The Delimiter Signature field provides a pattern that can be used to detect an MPDU delimiter when scanning for an MPDU delimiter.

[0099] It is envisioned in future IEEE 802.11 standards that a STA (AP STA or non-AP STA) may access a non-primary channel to communicate with another STA. Such operation may be referred to as non-primary channel access (NPCA) operation. Specifically, in addition to a default primary channel (which is used by all STAs in the BSS), the STA may have one or more secondary channels considered as NPCA 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. FIG. 10 shows an example that illustrates non-primary channel access (NPCA) operation. For the purpose of illustration, NPCA operation is contrasted with single primary channel (non-NPCA STA) operation. As shown in FIG. 10, 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. 10. For example, the NPCA primary channel may correspond to SCH1.Docket No.: 24-3041 PCT

[0100] In an implementation, as shown in FIG. 11 , 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. 10, 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).

[0101] In contrast, as shown in FIG. 11 , 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. 10, 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.

[0102] 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”).

[0103] 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 throughout the medium synchronization duration. An NPCA STA that does not support this capability may perform CS on a single channel at a time. In an implementation, an NPCA STA may perform CS on the PCH by default, and when the PCH is found busy, the STA may perform CS on the NPCA PCH. Such a STA is referred to herein as a non-concurrent CCA NPCA STA (such a STA may also be referred to as a non-concurrent CCA MPC STA or a Type 2 STA). In contrast to the concurrent CCA NPCA STA, a non-concurrent CCA NPCA STA may only synchronize to the NPCA PCH after the PCH is found busy. Hence, it may need to listen to the channel for at least a medium synchronization duration (if it does not receive any frame that includes NAV information) before it is able to transmit.Docket No.: 24-3041 PCT

[0104] FIG. 12 shows an example 1200 that illustrates an NPCA operation. As shown in FIG. 12, example 1200 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).

[0105] Example 1200 may begin with the AP transmitting a frame 1202 on the PCH. Frame 1202 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 1202 may be a management frame, such as a beacon frame, for example.

[0106] Subsequently, while the AP and STA operate on the PCH, transmission of a frame 1204 from an OBSS may begin on the PCH. The AP and the STA may detect frame 1204 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 1204 on the PCH. Frame 1204 may indicate a transmission (of one or more frames including frame 1204) on the PCH. A duration of the transmission on the PCH may be provided by a duration field of frame 1204, a transmission opportunity (TXOP) duration field of an OBSS PPDU comprising frame 1204, or a length field of the OBSS 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).

[0107] In accordance with NPCA operation, on receiving an OBSS 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. 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.

[0108] 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 1202). In example 1200, 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 1206 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 1206 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. 12) on the NPCA PCH.Docket No.: 24-3041 PCT

[0109] FIG. 13 shows an example 1300 that illustrates an inefficiency that may arise in the NPCA operation of FIG. 12. As described above, according to NPCA operation, the AP and STA may be configured to switch to the NPCA PCH after obtaining the OBSS NAV duration indicated in the OBSS PPDU. The AP and STA may operate on the NPCA PCH for the OBSS NAV duration, before returning to the PCH before an end of the OBSS NAV duration. In some cases (e.g., where the OBSS PPDU is an HE PPDU, an Extremely High Throughput (EHT) PPDU, or an Ultra-High Reliability (UHR) PPDU), the AP and STA may be configured to obtain the OBSS NAV duration from a signal (SIG) field of a preamble or PHY header of the OBSS PPDU. As such, the AP and STA may switch to the NPCA PCH after decoding the preamble or PHY header of the OBSS PPDU, without decoding the remainder of (e.g., an A-MPDU contained within) the OBSS PPDU, or after decoding the SIG field, without decoding the remainder of (e.g., additional / enhanced short training field (STF) or long training field (LTF) fields (e.g., HE-STF, EHT-STF, HE-LTF, or EHT-LTF)) the OBSS PPDU.

[0110] In other cases, the AP and / or STA may not be able to obtain the OBSS NAV duration from the preamble or PHY header of the OBSS PPDU. For example, the OBSS PPDU may be a High Throughput (HT) PPDU or a VHT PPDU that does not include a SIG field in the preamble or PHY header providing the OBSS NAV duration. In another example, the OBSS PPDU may be an HE+ PPDU (e.g., HE PPDU, EHT PPDU, UHR PPDU) with the OBSS NAV duration not specified (or with a non-valid duration) in the SIG field (e.g., a TXOP field of the SIG field that provides the OBSS NAV duration may be set by the transmitting STA to the value UNSPECIFIED). In such cases, the AP and / or STA may be configured to obtain the OBSS NAV duration by decoding one or more MPDU of the OBSS PPDU and to switch to the NPCA PCH after decoding the one or more MPDU. Specifically, the AP and / or STA may obtain the OBSS NAV duration from a Duration / ID field of a MAC header of a first occurring MPDU (or a subsequent MPDU) of the OBSS PPDU. This operation is illustrated in example 1300, in which the AP and STA switch to the NPCA PCH after decoding a first occurring MPDU (MPDU 1 ) of an OBSS (inter-BSS) PPDU being received on the PCH.

[0111] An inefficiency with this operation, however, is that the AP and / or STA may be delayed to switch to the NPCA PCH after detecting the inter-BSS PPDU. This may reduce the time available for communication between the AP and the STA on the NPCA PCH after switching to the NPCA PCH. For example, as shown in example 1300, after switching to the NPCA PCH, the AP may wish to transmit to the STA a data frame via the NPCA PCH. However, due to the late switching to the NPCA PCH, the AP may determine that the remaining duration of the OBSS NAV duration is not long enough to perform the transmission of the data frame via the NPCA PCH before the end of the OBSS NAV duration For example, as shown in example 1300, the AP may determine that the time required to transmit the data frame (including the time to transmit an initial control frame (ICF) to the STA to initiate a TXOP for the transmission of the data frame, the time to receive an initial control response (ICR) from the STA in response to the ICF, the time to transmit the data frame to the STA, the time to receive a BA frame from the STA in response to the data frame, and the durations of the SIFSs between those frames) is larger than the remaining duration of the OBSS NAVDocket No.: 24-3041 PCT duration. As the AP may be configured to return to the PCH before the end of the OBSS NAV duration, the AP may refrain from initiating the transmission of the data frame to the STA on the NPCA PCH. As such, despite the AP and STA switching to the NPCA PCH, the AP and STA may not use the NPCA PCH for any communication. In some cases, this may result in buffered traffic between the AP and STA being delayed and / or discarded (e.g., when the buffered traffic comprises low-latency traffic) and the NPCA PCH resources being wasted / under-utilized during the OBSS NAV duration.

[0112] Embodiments of the present disclosure, as further described below, address the above-described problem of existing technologies. In an aspect, an AP / STA determines that a PPDU being received via a PCH comprises an inter-BSS (or OBSS) PPDU. The AP / STA decodes an MPDU delimiter of an MPDU of the PPDU to determine a length of the MPDU. The MPDU may be a first occurring MPDU (or a subsequent MPDU) of the PPDU. Based on a length of the MPDU being larger than a threshold, the AP / STA switches from the PCH to an NPCA PCH. In an embodiment, based on the length of the MPDU being larger than the threshold, the AP / STA switches from the PCH to the NPCA PCH without decoding a MAC header or a frame body of the MPDU or before receiving an FCS field of the MPDU. As such, the AP / STA may switch to the NPCA PCH earlier than in existing NPCA operation when the MPDU is longer than the threshold (and may require a longer time to receive and decode by the AP / STA to obtain the OBSS NAV duration). This increases the time available for communication between the AP and the STA on the NPCA PCH after the AP and STA switch to the NPCA PCH. In another embodiment, based on the length of the MPDU being less than or equal to the threshold, the AP / STA may decode the MPDU to obtain the OBSS NAV duration before switching to the NPCA PCH. This enables the AP / STA to operate on the NPCA PCH for a longer time (until the end of the OBSS NAV duration) during the OBSS NAV duration, without incurring a significant delay to switch to the NPCA PCH (being short, the MPDU can be decoded relatively quickly by the AP / STA to obtain the OBSS NAV duration). In a further embodiment, the AP / STA obtains duration information from the PPDU. In an embodiment, the duration information indicates a value for a TXOP for a transmission comprising the PPDU. Based on the duration information being larger than a threshold, the AP / STA switches from the PCH to the NPCA PCH.

[0113] FIG. 14 shows an example 1400 that illustrates an example NPCA operation according to an embodiment. Example 1400 is provided for the purpose of illustration only and is not limiting of embodiments. As shown in FIG. 14, example 1400 includes an AP 1402 and a STA 1404. AP 1402 and STA 1404 belong to the same BSS. STA 1404 may be associated with AP 1402. AP 1402 and STA 1404 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).

[0114] AP 1402 and STA 1404 may each support an NPCA (switching) mode (or NPCA operation mode). According to the NPCA mode, AP 1402 (or STA 1404) may be configured, after determining that a PPDU being received via the PCH comprises an inter-BSS (or OBSS) PPDU (and, optionally, after failing to obtainDocket No.: 24-3041 PCT an OBSS NAV duration from a preamble or a PHY header of the PPDU), to decode (process, parse, or read) an MPDU delimiter of an MPDU (or MAC frame) of the PPDU to determine a length of the MPDU. The MPDU may be a first occurring MPDU (or a subsequent PPDU, e.g., second occurring MPDU) of the PPDU. As described in FIG. 9 above, the MPDU delimiter occurs before (precedes) the MPDU in the PPDU. As the MPDU delimiter includes its own CRC field, AP 402 (or STA 1404) may determine whether the MPDU delimiter was decoded correctly. AP 1402 (or STA 1404) may be further configured to switch from PCH to the NPCA PCH at a time based on the length of the MPDU. In an embodiment, switching from the PCH to the NPCA PCH comprises operating (parking / camping) on the NPCA PCH.

[0115] In an embodiment, based on the length of the MPDU being larger than a threshold, AP 1402 (or STA 1404) may be configured to switch from the PCH to the NPCA PCH after (or immediately after) decoding the MPDU delimiter. In an implementation of this embodiment, AP 1402 (or STA 1404) may be configured to switch from the PCH to the NPCA PCH without decoding (processing, parsing, or reading) a MAC header of the MPDU. In another implementation, AP 1402 (or STA 1404) may be configured to switch from the PCH to the NPCA PCH without decoding (processing, parsing, or reading) a frame body of the MPDU. AP 1402 (or STA 1404) may or may not decode the MAC header according to this implementation. In a further implementation, AP 1402 (or STA 1404) may be configured to switch from the PCH to the NPCA PCH without decoding (processing, parsing, or reading) the MPDU. In a further implementation, AP 1402 (or STA 1404) may be configured to switch from the PCH to the NPCA PCH after decoding (processing, parsing, or reading) the MPDU delimiter and before receiving an FCS field of the MPDU. In a further implementation, AP 1402 (or STA 1404) may be configured to switch from the PCH to the NPCA PCH after decoding (processing, parsing, or reading) the MPDU delimiter and while receiving a frame body of the MPDU.

[0116] Conversely, based on the length of the MPDU being less than or equal to the threshold, AP 1402 (or STA 1404) may be configured to switch from the PCH to the NPCA PCH after decoding the MPDU (or at least a MAC header of the MPDU) to obtain the OBSS NAV duration from the MPDU. In an embodiment, AP 1402 (or STA 1404) may be configured to decode (process, parse, or read) a duration field of the MPDU to obtain the OBSS NAV duration. The duration field may be a field (e.g., Duration / ID field) of a MAC header of the MPDU. As mentioned above, the OBSS NAV duration indicates a value for setting a NAV for a transmission comprising the inter-BSS PPDU and / or a value for a TXOP for a transmission comprising the inter-BSS PPDU. AP 1402 (or STA 1404) may set their basic NAVs based on the OBSS NAV duration obtained from the MPDU.

[0117] As mentioned above, the MPDU may be the first occurring MPDU of the PPDU. In an embodiment, if AP 1402 (or STA 1404) fails to decode the MPDU delimiter of the first occurring MPDU, AP 1402 (or STA 1404) may be configured to locate a next MPDU delimiter for a next MPDU in the PPDU and to repeat the process described above with respect to the next MPDU delimiter. In another embodiment (as illustrated further below in FIG. 16), if AP 1402 (or STA 1404) fails to decode the MPDU delimiter of the first occurringDocket No.: 24-3041 PCTMPDU, AP 1402 (or STA 1404) may be configured to switch from the PCH to the NPCA PCH after the MPDU delimiter. In another embodiment, if AP 1402 (or STA 1404) fails to obtain the OBSS NAV duration from the first occurring MPDU (e.g., AP 1402 (or STA 1404) fails to decode the first occurring MPDU or the first occurring MPDU does not indicate the OBSS NAV duration), AP 1402 (or STA 1404) may locate a next MPDU delimiter for a next MPDU in the PPDU and to repeat the process described above with respect to the next MPDU. In another embodiment, if AP 1402 (or STA 1404) fails to obtain the OBSS NAV duration from the first occurring MPDU (e.g., AP 1402 (or STA 1404) fails to decode the first occurring MPDU or the first occurring MPDU does not indicate the OBSS NAV duration), AP 1402 (or STA 1404) may be configured to switch from the PCH to the NPCA PCH (e.g., without trying to locate a next MPDU delimiter).

[0118] In a further embodiment, AP 1402 (or STA 1404) may be configured to obtain duration information from the PPDU being received via the PCH. In an embodiment, the duration information indicates a value for a TXOP for / associated with one or more transmission comprising the PPDU. Based on the duration information being larger than a threshold, AP 1402 (or STA 1404) may be configured to switch from the PCH to the NPCA PCH. In an embodiment, the duration information is equal to a remaining duration of the PPDU. In another embodiment, the duration information is equal to the remaining duration of the PPDU plus the duration of the TXOP or a NAV value derived from the PPDU. In an embodiment, the duration of the TXOP or the NAV value is obtained from a TXOP_DURATION parameter of an RXVECTOR derived from the PPDU.

[0119] In an embodiment, AP 1402 may indicate the threshold to STA 1404. The threshold may be recommended, preferred, or requested by AP 1402. In another embodiment, STA 1404 may indicate the threshold to AP 1402. The threshold may be recommended, preferred, or requested by STA 1404. In a further embodiment, the threshold may be pre-configured within AP 1402 or STA 1404.

[0120] In an embodiment, AP 1402 (or STA 1404) may be configured to determine that the PPDU comprises an inter-BSS PPDU based on receiving the PPDU from a STA that does not belong to a BSS of AP 1402. In an embodiment, AP 1402 (or STA 1404) may be configured to decode (read, detect, process, parse, or receive) a signal (SIG) field of the PPDU to determine whether the PPDU is an inter-BSS PPDU. The SIG field may be located in a preamble or a PHY header of the PPDU. In an embodiment, AP 1402 (or STA 1404) may decode (read, detect, process, parse, or receive) a BSS color field of the SIG field (or a field indicating a BSS color of the SIG field). AP 1402 (or STA 1404) may determine that the PPDU is an inter-BSS PPDU based on the BSS color field indicating a first BSS color (or a first BSSID) different than a second BSS color (or a second BSSID) of AP 1402. Depending on the type of PPDU, the SIG field may comprise a U-SIG, a UHR SIG, an EHT SIG, an HE SIG-A / B, a VHT SIG-A / B, or an HT SIG, for example. The SIG field may be a universal SIG (U-SIG) field, for example when the PPDU comprises an extremely high throughput (EHT) PPDU, an ultra-high reliability (UHR) PPDU, or a UHR+ PPDU. The SIG field may be an HE-SIG-A field, for example when the PPDU comprises a high efficiency (HE) PPDU. In another embodiment, AP 1402 (or STA 1404) may be configured to determine that the PPDU comprises an inter-BSS PPDU based on decodingDocket No.: 24-3041 PCT(processing, detecting, reading, receiving, or parsing) one or more MPDU of the PPDU and the one or more MPDU indicating / comprising a first BSSID different than a second BSSID of AP 1402.

[0121] Returning to FIG. 14, example 1400 begins with a PPDU 1406 being transmitted on the PCH PPDU 1406 may be transmitted by a STA that does not belong to the BSS of APs 1402 and STA 1404. PPDU 1406 is therefore an inter-BSS (or OBSS) PPDU for APs 1402 and STA 1404. As AP 1402 and STA 1404 operate on the PCH, AP 1402 and / or STA 1404 may (in parallel) detect / sense the transmission of PPDU 1406 and begin to decode (read, detect, process, parse, or receive) PPDU 1406. In an example, AP 1402 and / or STA 1404 may decode (read, detect, process, parse, or receive) a PHY identifier field of PPDU 1406, which allows AP 1402 and STA 1404 to determine a PPDU type of PPDU 1406.

[0122] Next, in an embodiment, AP 1402 and / or STA 1404 may decode (read, detect, process, parse, or receive) a preamble / PHY header of PPDU 1406 to determine if PPDU 1406 is an inter-BSS PPDU. As described above, AP 1402 and / or STA 1404 may decode (read, detect, process, parse, or receive) a BSS color field of a SIG field of the preamble / PHY header to determine whether PPDU 1406 is an inter-BSS PPDU. In example 1400, AP 1402 and / or STA 1404 may determine that PPDU 1406 is an inter-BSS PPDU based on the BSS color field indicating a first BSS color (or a first BSSID) that is different than a second BSS color (or a second BSSID) of AP 1402.

[0123] In another embodiment (not shown in FIG. 14), alternatively or additionally, AP 1402 and / or STA 1404 may decode (read, detect, process, parse, or receive) an MPDU (or a MAC header of the MPDU) of PPDU 1406 to determine if PPDU 1406 is an inter-BSS PPDU. The MPDU may be a first occurring MPDU of PPDU 1406. In an embodiment, AP 1402 and / or STA 1404 may be configured to decode (read, detect, process, parse, or receive) the MPDU of PPDU 1406 to determine if PPDU 1406 is an inter-BSS PPDU based on failing to determine whether PPDU 1406 is an inter-BSS PPDU based on reading / decoding the preamble / PHY header of PPDU 1406. As described above, AP 1402 and / or STA 1404 may decode (read, detect, process, parse, or receive) one or more address fields (e.g., Address 1 , Address 2, Address 3, and / or Address 4) including a BSSID field of the MPDU to determine whether the BSSID field indicates a MAC address different than a MAC address of AP 1402.

[0124] Continuing with example 1400, after determining that PPDU 1406 is an inter-BSS PPDU (and, optionally, after failing to obtain an OBSS NAV duration from a preamble or a PHY header of PPDU 1406), AP 1402 and / or STA 1404 may decode (process, parse, or read) an MPDU delimiter of an MPDU (or MAC frame) of PPDU 1406 to determine a length (x) of the MPDU. The MPDU may be a first occurring MPDU (or a subsequent PPDU, e.g., second occurring MPDU) of PPDU 1406. AP 1402 and STA 1404 may then compare the determined length (x) of the MPDU to a threshold to determine the switching time to the NPCA PCH.

[0125] In example 1400, AP 1402 and STA 1404 decode the MPDU delimiter of a first occurring MPDU (MPDU1) of PPDU 1406 and determine that the length of the first occurring MPDU is larger than theDocket No.: 24-3041 PCT threshold. Based on this determination, AP 1402 and STA 1404 switch from the PCH to the NPCA PCH after (or immediately after) decoding the MPDU delimiter. In an embodiment, AP 1402 and STA 1404 may be configured to switch to the NPCA PCH at the same switching time. The switching time may correspond to the time that AP 1402 and STA 1404 finish decoding / reading the MPDU delimiter. However, other switching times may also be configured or negotiated / agreed between AP 1402 and STA 1404. In example 1400, AP 1402 and STA 1404 do not decode (process, parse, or read) a MAC header and a frame body of the first occurring MPDU or the remainder of PPDU 1406.

[0126] Subsequently, AP 1402 may access the NPCA PCH and transmit a frame 1408 to STA 1404. As shown in FIG. 14, frame 1408 may be transmitted via a bandwidth that comprises the NPCA PCH. For example, frame 1408 may be transmitted via the NPCH PCH and SCH2. Frame 1408 may comprise an initial control frame (ICF), a request-to-send (RTS) frame, a multi-user (MU)-RTS frame, a buffer status report poll (BSRP) trigger frame, a block ack request (BAR) frame, a clear-to-send (CTS) frame, a block ack (BA) frame, an acknowledgment (Ack) frame, a buffer status report (BSR) frame, an initial control response frame (ICR), a request frame, a control frame, a management frame, or an action frame, for example. STA 1404 may respond to frame 1408 from AP 1402 by transmitting a frame 1410 to AP 1402. Frame 1410 may comprise a clear-to-send (CTS) frame, a BlockAck (BA) frame, an acknowledgment (Ack) frame, a buffer status report (BSR) frame, an initial control response frame (ICR), a response frame, a control frame, a management frame, or an action frame, for example.

[0127] AP 1402 may then transmit a frame 1412 to STA 1404. Frame 1412 may comprise a data frame, a management frame, or an action frame, for example. STA 1404 may respond to frame 1412 by transmitting a frame 1414 to AP 1402. Frame 1414 may comprise an immediate response frame, such as an Ack frame or a BA frame. As such, communication between AP 1402 and STA 1404 may occur on the NPCA PCH during at least the transmission time of PPDU 1406 on the PCH. This allows for buffered traffic between AP 1402 and STA 1404 to be transmitted with minimal delay and avoids NPCA PCH resources from being wasted. In example 1400, as AP 1402 and STA 1404 switch to the NPCA PCH without determining the OBSS NAV duration associated with PPDU 1406, AP 1402 and STA 1404 finish communicating on the NPCA PCH and return to the PCH before an end of PPDU 1406.

[0128] FIG. 15 shows another example 1500 of the NPCA operation described with reference to FIG. 14 above. Example 1500 is provided for the purpose of illustration only and is not limiting of embodiments. As in example 1400, example 1500 also includes AP 1402 and STA 1404 described above. AP 1402 and STA 1404 may be configured as discussed above with respect to FIG. 14.

[0129] Example 1500 begins with a PPDU 1502 being transmitted on the PCH. PPDU 1502 may be transmitted by a STA that does not belong to the BSS of APs 1402 and STA 1404. PPDU 1502 is therefore an inter-BSS (or OBSS) PPDU for APs 1402 and STA 1404. As AP 1402 and STA 1404 operate on the PCH, AP 1402 and / or STA 1404 may (in parallel) detect / sense the transmission of PPDU 1502 and begin to decodeDocket No.: 24-3041 PCT(read, detect, process, parse, or receive) PPDU 1502. In an example, AP 1402 and / or STA 1404 may decode (read, detect, process, parse, or receive) a PHY identifier field of PPDU 1502, which allows AP 1402 and STA 1404 to determine a PPDU type of PPDU 1502. Next, as described above, AP 1402 and / or STA 1404 may decode (read, detect, process, parse, or receive) a preamble / PHY header (or an MPDU) of PPDU 1502 to determine if PPDU 1502 is an inter-BSS PPDU.

[0130] After determining that PPDU 1502 is an inter-BSS PPDU (and, optionally, after failing to obtain an OBSS NAV duration from a preamble or a PHY header of PPDU 1502), AP 1402 and / or STA 1404 may decode (process, parse, or read) an MPDU delimiter of an MPDU (or MAC frame) of PPDU 1502 to determine a length (x) of the MPDU. The MPDU may be a first occurring MPDU (or a subsequent PPDU, e.g., second occurring MPDU) of PPDU 1502. AP 1402 and STA 1404 may then compare the determined length (x) of the MPDU to the threshold to determine the switching time to the NPCA PCH.

[0131] In example 1500, AP 1402 and STA 1404 decode the MPDU delimiter of a first occurring MPDU (MPDU1) of PPDU 1502 and determine that the length of the first occurring MPDU is less than or equal to the threshold. Based on this determination, AP 1402 and STA 1404 decode the first occurring MPDU (or at least a MAC header of the first occurring MPDU) to obtain the OBSS NAV duration associated with PPDU 1502. As described above, AP 1402 and STA 1404 may decode (process, parse, or read) a Duration / ID field of the MAC header of the first occurring MPDU to obtain the OBSS NAV duration. After obtaining the OBSS NAV duration, AP 1402 and STA 1404 switch from the PCH to the NPCA PCH. In an embodiment, AP 1402 and STA 1404 may be configured to switch to the NPCA PCH at the same switching time. The switching time may correspond to the time that AP 1402 and STA 1404 finish decoding / reading the MAC header of the MPDU or the entire MPDU as shown in FIG. 15. However, other switching times may also be configured or negotiated / agreed between AP 1402 and STA 1404.

[0132] Subsequently, AP 1402 may access the NPCA PCH and transmit a frame 1504 to STA 1404. As shown in FIG. 15, frame 1504 may be transmitted via a bandwidth that comprises the NPCA PCH. For example, frame 1504 may be transmitted via the NPCH PCH and SCH2. Frame 1504 may comprise an initial control frame (ICF), a request-to-send (RTS) frame, a multi-user (MU)-RTS frame, a buffer status report poll (BSRP) trigger frame, a block ack request (BAR) frame, a clear-to-send (CTS) frame, a block ack (BA) frame, an acknowledgment (Ack) frame, a buffer status report (BSR) frame, an initial control response frame (ICR), a request frame, a control frame, a management frame, or an action frame, for example. STA 1404 may respond to frame 1504 from AP 1402 by transmitting a frame 1506 to AP 1402. Frame 1506 may comprise a clear-to-send (CTS) frame, a BlockAck (BA) frame, an acknowledgment (Ack) frame, a buffer status report (BSR) frame, an initial control response frame (ICR), a response frame, a control frame, a management frame, or an action frame, for example.

[0133] AP 1402 may then transmit a frame 1508 to STA 1404. Frame 1508 may comprise a data frame, a management frame, or an action frame, for example. STA 1404 may respond to frame 1508 by transmittingDocket No.: 24-3041 PCT a frame 1510 to AP 1402. Frame 1510 may comprise an immediate response frame, such as an Ack frame or a BA frame. In example 1500, as AP 1402 and STA 1404 switch to the NPCA PCH after determining the OBSS NAV duration associated with PPDU 1502, AP 1402 and STA 1404 may communicate on the NPCA PCH until the end of the OBSS NAV duration. AP 1402 and STA 1404 return to the PCH before or at the end of the OBSS NAV duration of PPDU 1502.

[0134] FIG. 16 shows an example 1600 that illustrates another example NPCA operation according to an embodiment. Example 1600 is provided for the purpose of illustration only and is not limiting of embodiments. As in example 1400, example 1600 also includes AP 1402 and STA 1404 described above. AP 1402 and STA 1404 may be configured as discussed above with respect to FIG. 14. Additionally, AP 1402 (and / or STA 1404) may be configured if AP 1402 (and / or STA 1404) fails to decode the MPDU delimiter of an MPDU of the inter-BSS PPDU (e.g., the first occurring MPDU of the inter-BSS PPDU) to switch (e.g., immediately) from the PCH to the NPCH.

[0135] Example 1600 begins with a PPDU 1602 being transmitted on the PCH. PPDU 1602 may be transmitted by a STA that does not belong to the BSS of APs 1402 and STA 1404. PPDU 1602 is therefore an inter-BSS (or OBSS) PPDU for APs 1402 and STA 1404. As AP 1402 and STA 1404 operate on the PCH, AP 1402 and / or STA 1404 may (in parallel) detect / sense the transmission of PPDU 1602 and begin to decode (read, detect, process, parse, or receive) PPDU 1602. In an example, AP 1402 and / or STA 1404 may decode (read, detect, process, parse, or receive) a PHY identifier field of PPDU 1602, which allows AP 1402 and STA 1404 to determine a PPDU type of PPDU 1602. Next, as described above, AP 1402 and / or STA 1404 may decode (read, detect, process, parse, or receive) a preamble / PHY header (or an MPDU) of PPDU 1602 to determine if PPDU 1602 is an inter-BSS PPDU.

[0136] After determining that PPDU 1602 is an inter-BSS PPDU (and, optionally, after failing to obtain an OBSS NAV duration from a preamble or a PHY header of PPDU 1602), AP 1402 and / or STA 1404 may decode (process, parse, or read) an MPDU delimiter of an MPDU (or MAC frame) of PPDU 1602 to determine a length (x) of the MPDU. The MPDU may be a first occurring MPDU (or a subsequent PPDU, e.g., second occurring MPDU) of PPDU 1602.

[0137] In example 1600, AP 1402 and STA 1404 fail to decode the MPDU delimiter of a first occurring MPDU (MPDU1 ) of PPDU 1602. Based on this failure, AP 1402 and STA 1404 switch from the PCH to the NPCA PCH after (or immediately after) failing to decode the MPDU delimiter. In example 1600, AP 1402 and STA 1404 do not decode (process, parse, or read) a MAC header and a frame body of the first occurring MPDU or the remainder of PPDU 1602.

[0138] Subsequently, AP 1402 may access the NPCA PCH and transmit a frame 1604 to STA 1404. As shown in FIG. 16, frame 1604 may be transmitted via a bandwidth that comprises the NPCA PCH. For example, frame 1604 may be transmitted via the NPCH PCH and SCH2. Frame 1604 may comprise an initial control frame (ICF), a request-to-send (RTS) frame, a multi-user (MU)-RTS frame, a buffer status report pollDocket No.: 24-3041 PCT(BSRP) trigger frame, a block ack request (BAR) frame, a clear-to-send (CTS) frame, a block ack (BA) frame, an acknowledgment (Ack) frame, a buffer status report (BSR) frame, an initial control response frame (ICR), a request frame, a control frame, a management frame, or an action frame, for example. STA 1404 may respond to frame 1604 from AR 1402 by transmitting a frame 1606 to AP 1402. Frame 1606 may comprise a clear-to-send (CTS) frame, a BlockAck (BA) frame, an acknowledgment (Ack) frame, a buffer status report (BSR) frame, an initial control response frame (ICR), a response frame, a control frame, a management frame, or an action frame, for example.

[0139] AP 1402 may then transmit a frame 1608 to STA 1404. Frame 1608 may comprise a data frame, a management frame, or an action frame, for example. STA 1404 may respond to frame 1608 by transmitting a frame 1610 to AP 1402. Frame 1610 may comprise an immediate response frame, such as an Ack frame or a BA frame. In example 1600, as AP 1402 and STA 1404 switch to the NPCA PCH without determining the OBSS NAV duration associated with PPDU 1602, AP 1402 and STA 1404 finish communicating on the NPCA PCH and return to the PCH before an end of PPDU 1602.

[0140] FIG. 17 shows an example 1700 that illustrates an example frame exchange according to an embodiment. Example 1700 is provided for the purpose of illustration only and is not limiting of embodiments. As in example 1400, example 1700 also includes AP 1402 and STA 1404 described above. AP 1402 and STA 1404 may be configured as discussed above with respect to FIG. 14. Additionally, AP 1402 and STA 1404 may be configured to perform the frame exchange illustrated in FIG. 17, which may performed prior to AP 1402 and STA 1404 receiving an inter-BSS PPDU on the PCH . For example, the example frame exchange illustrated in FIG. 17 may be performed in example 1400 before AP 1402 and STA 1404 receive / detect PPDU 1406, in example 1500 before AP 1402 and STA 1404 receive / detect PPDU 1502, or in example 1600 before AP 1402 and STA 1404 receive / detect PPDU 1602.

[0141] As shown in FIG. 17, the example frame exchange may include AP 1402 transmitting a frame 1702 on the PCH. In an embodiment, frame 1702 may indicate support, by AP 1402, of a frame size-based NPCA switching operation. The frame size-based NPCA switching operation corresponds to the NPCA switching operation (described above) and that is based on the length / size of an MPDU (frame) of a received inter- BSS PPDU. In an embodiment, frame 1702 may further indicate enablement / disablement, by AP 1402, of the frame size-based NPCA switching operation. In an embodiment, frame 1702 may further indicate the threshold to be applied for the frame size-based NPCA switching operation. In embodiments, the first frame may comprise a beacon frame, a fast initial link setup (FILS) discovery frame, a traffic indication map (TIM) broadcast frame, a broadcast probe response frame, a broadcast frame, a control frame, a management frame, an action frame, a quality of service (QoS) null frame, or a QoS data frame.

[0142] The example frame exchange may further include, before or after the transmission of frame 1702, STA 1404 transmitting a frame 1704 to AP 1402. In an embodiment, frame 1704 may indicate support, by STA 1404, of the frame size-based NPCA switching operation. In an embodiment, frame 1704 may furtherDocket No.: 24-3041 PCT indicate enablement / disablement, by STA 1404, of the frame size-based NPCA switching operation. In an embodiment, frame 1704 may further indicate the threshold to be applied for the frame size-based NPCA switching operation. In an embodiment, where frame 1704 indicates enablement, by STA 1404, of the frame size-based NPCA switching operation, frame 1704 may further comprise a request to AP 1402 to enable the frame size-based NPCA switching operation by AP 1402. In embodiments, frame 1704 may comprise an individually addressed probe request frame, association request frame, request frame, control frame, management frame, action frame, quality of service (QoS) null frame, or QoS data frame.

[0143] The example frame exchange may further include, before or after the transmission of frame 1702, AP 1402 transmitting a frame 1706 to STA 1404. In an embodiment, frame 1706 may indicate support, by AP 1402, of the frame size-based NPCA switching operation. In an embodiment, frame 1704 may further indicate enablement / disablement, by AP 1402, of the frame size-based NPCA switching operation. In an embodiment, frame 1706 may further indicate the threshold to be applied for the frame size-based NPCA switching operation. Frame 1706 may be in response to frame 1704. In an embodiment, where frame 1704 comprises a request to AP 1402 to enable the frame size-based NPCA switching operation by AP 1402, frame 1706 may indicate acceptance / rejection of the request. In embodiments, frame 1706 may comprise an individually addressed probe response frame, association response frame, response frame, control frame, management frame, action frame, quality of service (QoS) null frame, or QoS data frame.

[0144] 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 an AP such as AP 1402. As shown in FIG. 18, example process 1800 may include steps 1802 and 1804.

[0145] Step 1802 includes determining, by the AP, that a PPDU being received via a PCH comprises an inter-BSS PPDU.

[0146] Step 1804 includes, based on a length of an MPDU of the PPDU being larger than a threshold, switching, by the AP, from the PCH to an NPCA PCH. In an embodiment, the MPDU comprises a first occurring MPDU of the PPDU. In an embodiment, the MPDU comprises a MAC frame.

[0147] In another embodiment, process 1800 may further comprise obtaining duration information from the PPDU. In an embodiment, the duration information indicates a value for a TXOP for a transmission comprising the PPDU. In an embodiment, step 1804 comprises, based on the duration information being larger than a threshold, switching, by the AP, from the PCH to the NPCA PCH. In an embodiment, the duration information is equal to a remaining duration of the PPDU. In another embodiment, the duration information is equal to the remaining duration of the PPDU plus the duration of the TXOP or a NAV value derived from the PPDU. In an embodiment, the duration of the TXOP or the NAV value is obtained from a TXOP_DURATION parameter of an RXVECTOR derived from the PPDU.Docket No.: 24-3041 PCT

[0148] In an embodiment, process 1800 further comprises decoding a delimiter of the MPDU to determine the length of the MPDU. The delimiter of the MPDU comprises an MPDU delimiter. The delimiter occurs before the MPDU in the PPDU. The length of the MPDU comprises an MPDU length.

[0149] In an embodiment, switching from the PCH to the NPCA PCH in step 1804 comprises switching from the PCH to the NPCA PCH without decoding a MAC header of the MPDU.

[0150] In an embodiment, switching from the PCH to the NPCA PCH in step 1804 comprises switching from the PCH to the NPCA PCH without decoding a frame body of the MPDU.

[0151] In an embodiment, switching from the PCH to the NPCA PCH in step 1804 comprises switching from the PCH to the NPCA PCH without decoding the MPDU.

[0152] In an embodiment, switching from the PCH to the NPCA PCH in step 1804 comprises switching from the PCH to the NPCA PCH after decoding the delimiter of the MPDU and before receiving a frequency checksum (FCS) field of the MPDU.

[0153] In an embodiment, switching from the PCH to the NPCA PCH in step 1804 comprises switching from the PCH to the NPCA PCH after decoding the delimiter of the MPDU and while receiving a frame body of the MPDU.

[0154] In an embodiment, process 1800 may further comprise, based on the length of the MPDU being less than or equal to the threshold, not switching, by the AP, from the PCH to the NPCA PCH right after decoding the delimiter of the MPDU.

[0155] In an embodiment, process 1800 may further comprise, based on the length of the MPDU being less than or equal to the threshold, decoding, by the AP, the MPDU after decoding the delimiter.

[0156] In an embodiment, process 1800 may further comprise obtaining, by the AP, duration information from the MPDU. In an embodiment, the MPDU comprises a duration field that comprises the duration information. In an embodiment, the duration field is located in a MAC header of the MPDU. In an embodiment, the duration information indicates a value for a NAV for a transmission comprising the PPDU. In another embodiment, the duration information indicates a value for a TXOP for a transmission comprising the PPDU.

[0157] In an embodiment, process 1800 may further comprise, based on a failure to decode a delimiter of the MPDU, switching, by the AP, from the PCH to the NPCA PCH.

[0158] In an embodiment, process 1800 may further comprise, based on a failure to decode the delimiter of the MPDU, locating / determining, by the AP, a next MPDU delimiter occurring after the delimiter.

[0159] In an embodiment, switching from the PCH to the NPCA PCH in step 1804 comprises operating on the NPCA PCH.

[0160] In an embodiment, process 1800 may further comprise transmitting, by the AP, a first frame indicating: support, by the AP, of a frame size-based NPCA switching operation; and / or enablement / disablement, by the AP, of the frame size-based NPCA switching operation. The first frame may comprise a beacon frame, a fast initial link setup (FILS) discovery frame, a traffic indication map (TIM)Docket No.: 24-3041 PCT broadcast frame, a broadcast probe response frame, a broadcast frame, a control frame, a management frame, an action frame, a quality of service (QoS) null frame, or a QoS data frame.

[0161] In an embodiment, process 1800 may further comprise receiving, by the AP from a STA, a second frame indicating: support, by the STA, of a frame size-based NPCA switching operation; and / or enablement / disablement, by the STA, of the frame size-based NPCA switching operation. The second frame may comprise an individually addressed probe request frame, association request frame, request frame, control frame, management frame, action frame, quality of service (QoS) null frame, or QoS data frame.

[0162] In an embodiment, process 1800 may further comprise, in response to the second frame, transmitting, by the AP to the STA, a third frame indicating: support, by the AP, of a frame size-based NPCA switching operation; and / or enablement / disablement, by the AP, of the frame size-based NPCA switching operation. The third frame may comprise an individually addressed probe response frame, association response frame, response frame, control frame, management frame, action frame, quality of service (QoS) null frame, or QoS data frame.

[0163] In an embodiment, process 1800 may further comprise transmitting, by the AP, a fourth frame comprising the threshold. The threshold may be recommended by the AP.

[0164] In another embodiment, process 1800 may further comprise receiving, by the AP from a STA, a fifth frame comprising the threshold. The threshold may be recommended by the STA.

[0165] In an embodiment, process 1800 may further comprise communicating, by the AP and during the PPDU, with the STA on the NPCA PCH. In another embodiment, process 1800 may further comprise communicating, by the AP and during duration information indicated in the PPDU, with the STA on the NPCA PCH.

[0166] In an embodiment, process 1800 may further comprise switching, by the AP, from the NPCA PCH to the PCH before an end of the PPDU, an end of a NAV determined based on the PPDU, or an end of a TXOP associated with the PPDU.

[0167] In an embodiment, determining that the PPDU comprises the inter-BSS PPDU in step 1802 comprises receiving the PPDU from a STA that does not belong to a BSS of the AP.

[0168] In an embodiment, determining that the PPDU comprises the inter-BSS PPDU in step 1802 comprises decoding a SIG field of the PPDU. In an embodiment, the PPDU comprises a preamble part or a PHY header, and the preamble part or PHY header comprises the SIG field. In an embodiment, the PPDU comprises an extremely high throughput (EHT) PPDU, an ultra-high reliability (UHR) PPDU, or a UHR+ PPDU, and wherein the SIG field comprises a universal SIG (U-SIG) field of the PPDU. In another embodiment, the PPDU comprises a high efficiency (HE) PPDU, and the SIG field comprises an HE-SIG-A field of the PPDU. In an embodiment, the SIG field indicates / comprises a BSS color field set to a first BSS color different than a second BSS color of the AP.Docket No.: 24-3041 PCT

[0169] In another embodiment, determining that the PPDU comprises the inter-BSS PPDU in step 1802 comprises decoding one or more MPDU of the PPDU where the one or more MPDU indicates / comprises a first BSSID different than a second BSSID of the AP.

[0170] FIG. 19 illustrates another example process 1900 according to an embodiment. Example process 1900 is provided for the purpose of illustration only and is not limiting of embodiments. Example process 1900 may be performed by a STA such as STA 1404. As shown in FIG. 19, example process 1900 may include steps 1902 and 1904.

[0171] Step 1902 includes determining, by the STA, that a PPDU being received via a PCH comprises an inter-BSS PPDU.

[0172] Step 1904 includes, based on a length of an MPDU of the PPDU being larger than a threshold, switching, by the STA, from the PCH to an NPCA PCH. In an embodiment, the MPDU comprises a first occurring MPDU of the PPDU. In an embodiment, the MPDU comprises a MAC frame.

[0173] In another embodiment, process 1900 may further comprise obtaining duration information from the PPDU. In an embodiment, the duration information indicates a value for a TXOP for a transmission comprising the PPDU. In an embodiment, step 1904 comprises, based on the duration information being larger than a threshold, switching, by the STA, from the PCH to the NPCA PCH. In an embodiment, the duration information is equal to a remaining duration of the PPDU. In another embodiment, the duration information is equal to the remaining duration of the PPDU plus the duration of the TXOP or a NAV value derived from the PPDU. In an embodiment, the duration of the TXOP or the NAV value is obtained from a TXOP_DURATION parameter of an RXVECTOR derived from the PPDU.

[0174] In an embodiment, process 1900 further comprises decoding a delimiter of the MPDU to determine the length of the MPDU. The delimiter of the MPDU comprises an MPDU delimiter. The delimiter occurs before the MPDU in the PPDU. The length of the MPDU comprises an MPDU length.

[0175] In an embodiment, switching from the PCH to the NPCA PCH in step 1904 comprises switching from the PCH to the NPCA PCH without decoding a MAC header of the MPDU.

[0176] In an embodiment, switching from the PCH to the NPCA PCH in step 1904 comprises switching from the PCH to the NPCA PCH without decoding a frame body of the MPDU.

[0177] In an embodiment, switching from the PCH to the NPCA PCH in step 1904 comprises switching from the PCH to the NPCA PCH without decoding the MPDU.

[0178] In an embodiment, switching from the PCH to the NPCA PCH in step 1904 comprises switching from the PCH to the NPCA PCH after decoding the delimiter of the MPDU and before receiving a frequency checksum (FCS) field of the MPDU.

[0179] In an embodiment, switching from the PCH to the NPCA PCH in step 1904 comprises switching from the PCH to the NPCA PCH after decoding the delimiter of the MPDU and while receiving a frame body of the MPDU.Docket No.: 24-3041 PCT

[0180] In an embodiment, process 1900 may further comprise, based on the length of the MPDU being less than or equal to the threshold, not switching, by the STA, from the PCH to the NPCA PCH right after decoding the delimiter of the MPDU.

[0181] In an embodiment, process 1900 may further comprise, based on the length of the MPDU being less than or equal to the threshold, decoding, by the STA, the MPDU after decoding the delimiter.

[0182] In an embodiment, process 1900 may further comprise obtaining, by the STA, duration information from the MPDU. In an embodiment, the MPDU comprises a duration field that comprises the duration information. In an embodiment, the duration field is located in a MAC header of the MPDU. In an embodiment, the duration information indicates a value for a NAV for a transmission comprising the PPDU. In another embodiment, the duration information indicates a value for a TXOP for a transmission comprising the PPDU.

[0183] In an embodiment, process 1900 may further comprise, based on a failure to decode a delimiter of the MPDU, switching, by the STA, from the PCH to the NPCA PCH.

[0184] In an embodiment, process 1900 may further comprise, based on a failure to decode the delimiter of the MPDU, locating / determining, by the STA, a next MPDU delimiter occurring after the delimiter.

[0185] In an embodiment, switching from the PCH to the NPCA PCH in step 1904 comprises operating on the NPCA PCH.

[0186] In an embodiment, process 1900 may further comprise receiving, by the STA from an AP, a first frame indicating: support, by the AP, of a frame size-based NPCA switching operation; and / or enablement / disablement, by the AP, of the frame size-based NPCA switching operation. The first frame may comprise a beacon frame, a fast initial link setup (FILS) discovery frame, a traffic indication map (TIM) broadcast frame, a broadcast probe response frame, a broadcast frame, a control frame, a management frame, an action frame, a quality of service (QoS) null frame, or a QoS data frame.

[0187] In an embodiment, process 1900 may further comprise transmitting, by the STA to the AP, a second frame indicating: support, by the STA, of a frame size-based NPCA switching operation; and / or enablement / disablement, by the STA, of the frame size-based NPCA switching operation. The second frame may comprise an individually addressed probe request frame, association request frame, request frame, control frame, management frame, action frame, quality of service (QoS) null frame, or QoS data frame.

[0188] In an embodiment, process 1900 may further comprise, in response to the second frame, receiving, by the STA from the AP, a third frame indicating: support, by the AP, of a frame size-based NPCA switching operation; and / or enablement / disablement, by the AP, of the frame size-based NPCA switching operation. The third frame may comprise an individually addressed probe response frame, association response frame, response frame, control frame, management frame, action frame, quality of service (QoS) null frame, or QoS data frame.

[0189] In an embodiment, process 1900 may further comprise receiving, by the STA from the AP, a fourth frame comprising the threshold. The threshold may be recommended by the AP.Docket No.: 24-3041 PCT

[0190] In another embodiment, process 1900 may further comprise transmitting, by the STA to the AP, a fifth frame comprising the threshold. The threshold may be recommended by the STA.

[0191] In an embodiment, process 1900 may further comprise communicating, by the STA and during the PPDU, with the AP on the NPCA PCH. In another embodiment, process 1900 may further comprise communicating, by the STA and during duration information indicated in the PPDU, with the AP on the NPCA PCH.

[0192] In an embodiment, process 1900 may further comprise switching, by the STA, from the NPCA PCH to the PCH before an end of the PPDU, an end of a NAV determined based on the PPDU, or an end of a TXOP associated with the PPDU.

[0193] In an embodiment, determining that the PPDU comprises the inter-BSS PPDU in step 1902 comprises receiving the PPDU from a STA that does not belong to a BSS of the STA.

[0194] In an embodiment, determining that the PPDU comprises the inter-BSS PPDU in step 1902 comprises decoding a SIG field of the PPDU. In an embodiment, the PPDU comprises a preamble part or a PHY header, and the preamble part or PHY header comprises the SIG field. In an embodiment, the PPDU comprises an extremely high throughput (EHT) PPDU, an ultra-high reliability (UHR) PPDU, or a UHR+ PPDU, and wherein the SIG field comprises a universal SIG (U-SIG) field of the PPDU. In another embodiment, the PPDU comprises a high efficiency (HE) PPDU, and the SIG field comprises an HE-SIG-A field of the PPDU. In an embodiment, the SIG field indicates / comprises a BSS color field set to a first BSS color different than a second BSS color of the AP.

[0195] In another embodiment, determining that the PPDU comprises the inter-BSS PPDU in step 1902 comprises decoding one or more MPDU of the PPDU where the one or more MPDU indicates / comprises a first BSSID different than a second BSSID of an AP with which the STA is associated.

Claims

1. Docket No.: 24-3041 PCTCLAIMSWhat is claimed is:

1. A method comprising: determining, by an access point (AP), that a physical layer protocol data unit (PPDU) being received via a primary channel (PCH) comprises an inter-basic service set (inter-BSS) PPDU; decoding, by the AP, a delimiter of a medium access protocol (MAC) protocol data unit (MPDU) of the PPDU to determine a length of the MPDU; based on the length of the MPDU being larger than a threshold, switching, by the AP, from the PCH to a non-primary channel access (NPCA) PCH; and communicating, by the AP, with a station (STA) on the NPCA PCH.

2. A method comprising: determining, by an access point (AP), that a physical layer protocol data unit (PPDU) being received via a primary channel (PCH) comprises an inter-basic service set (inter-BSS) PPDU; and based on a length of a medium access protocol (MAC) protocol data unit (MPDU) of the PPDU being larger than a threshold, switching, by the AP, from the PCH to a non-primary channel access (NPCA) PCH.

3. The method of claim 2, wherein the MPDU comprises a first occurring MPDU of the PPDU.

4. The method of any of claims 2-3, further comprising decoding a delimiter of the MPDU to determine the length of the MPDU.

5. The method of claim 4, wherein the delimiter of the MPDU comprises an MPDU delimiter.

6. The method of any of claims 4-5, wherein the delimiter occurs before the MPDU in the PPDU.

7. The method of any of claims 4-6, wherein the length of the MPDU comprises an MPDU length.

8. The method of any of claims 2-7, wherein the switching from the PCH to the NPCA PCH comprises switching from the PCH to the NPCA PCH without decoding a MAC header of the MPDU.

9. The method of any of claims 2-8, wherein the switching from the PCH to the NPCA PCH comprises switching from the PCH to the NPCA PCH without decoding a frame body of the MPDU.

10. The method of any of claims 2-9, wherein the switching from the PCH to the NPCA PCH comprises switching from the PCH to the NPCA PCH without decoding the MPDU.1 1. The method of any of claims 4-10, wherein the switching from the PCH to the NPCA PCH comprises switching from the PCH to the NPCA PCH after decoding the delimiter of the MPDU and before receiving a frequency checksum (FCS) field of the MPDU.

12. The method of any of claims 4-11 , wherein the switching from the PCH to the NPCA PCH comprises switching from the PCH to the NPCA PCH after decoding the delimiter of the MPDU and while receiving a frame body of the MPDU.Docket No.: 24-3041 PCT13. The method of any of claims 4-12, further comprising based on the length of the MPDU being less than or equal to the threshold, not switching, by the AP, from the PCH to the NPCA PCH right after decoding the delimiter of the MPDU.

14. The method of any of claims 4-12, further comprising based on the length of the MPDU being less than or equal to the threshold, decoding, by the AP, the MPDU after decoding the delimiter.

15. The method of claim 14, further comprising obtaining, by the AP, duration information from the MPDU.

16. The method of claim 15, wherein the MPDU comprises a duration field, and wherein the duration field comprises the duration information.

17. The method of claim 16, wherein a MAC header of the MPDU comprises the duration field.

18. The method of any of claims 15-17, wherein the duration information indicates a value for a network allocation vector (NAV) for a transmission comprising the PPDU.

19. The method of any of claims 15-17, wherein the duration information indicates a value for a transmission opportunity (TXOP) for a transmission comprising the PPDU.

20. The method of any of claims 2-19, wherein the MPDU comprises a MAC frame.21 . The method of any of claims 2-3, further comprising based on a failure to decode a delimiter of the MPDU, switching, by the AP, from the PCH to the NPCA PCH.

22. The method of any of claims 2-3, further comprising based on a failure to decode a delimiter of the MPDU, locating / determining, by the AP, a next MPDU delimiter occurring after the delimiter.

23. The method of any of claims 2-22, wherein the switching from the PCH to the NPCA PCH comprises operating on the NPCA PCH.

24. The method of any of claims 2-23, further comprising transmitting, by the AP, a first frame indicating: support, by the AP, of a frame size-based NPCA switching operation; and / or enablement / disablement, by the AP, of the frame size-based NPCA switching operation.

25. The method of claim 24, wherein the first frame comprises a beacon frame, a fast initial link setup (FILS) discovery frame, a traffic indication map (TIM) broadcast frame, a broadcast probe response frame, a broadcast frame, a control frame, a management frame, an action frame, a quality of service (QoS) null frame, or a QoS data frame.

26. The method of any of claims 2-25, further comprising: receiving, by the AP from a station (STA), a second frame indicating: support, by the STA, of a frame size-based NPCA switching operation; and / or enablement / disablement, by the STA, of the frame size-based NPCA switching operation; and in response to the second frame, transmitting, by the AP to the STA, a third frame indicating: support, by the AP, of a frame size-based NPCA switching operation; and / or enablement / disablement, by the AP, of the frame size-based NPCA switching operation.Docket No.: 24-3041 PCT27. The method of claim 26, wherein the second frame comprises an individually addressed probe request frame, association request frame, request frame, control frame, management frame, action frame, quality of service (QoS) null frame, or QoS data frame.

28. The method of claim 26, wherein the third frame comprises an individually addressed probe response frame, association response frame, response frame, control frame, management frame, action frame, quality of service (QoS) null frame, or QoS data frame.

29. The method of any of claims 2-28, further comprising transmitting, by the AP, a fourth frame comprising the threshold.

30. The method of any of claims 2-29, wherein the threshold is recommended by the AP.

31. The method of any of claims 2-28, further comprising receiving, by the AP from a STA, a fifth frame comprising the threshold.

32. The method of claim 31 , wherein the threshold is recommended by the STA.

33. The method of any of claims 2-32, further comprising communicating, by the AP and during the PPDU, with a station (STA) on the NPCA PCH.

34. The method of any of claims 2-33, further comprising communicating, by the AP and during duration information indicated in the PPDU, with a station (STA) on the NPCA PCH.

35. The method of any of claims 2-34, further comprising switching, by the AP, from the NPCA PCH to the PCH before an end of the PPDU, an end of a network allocation vector (NAV) determined based on the PPDU, or an end of a transmit opportunity (TXOP) associated with the PPDU.

36. The method of any of claims 2-35, wherein determining that the PPDU comprises the inter-BSS PPDU comprises receiving the PPDU from a STA that does not belong to a basic service set (BSS) of the AP.

37. The method of any of claims 2-36, wherein determining that the PPDU comprises the inter-BSS PPDU comprises decoding a signal (SIG) field of the PPDU.

38. The method of claim 37, wherein the PPDU comprises a preamble part or a PHY header, and wherein the preamble part or the PHY header comprises the SIG field.

39. The method of any of claims 37-38, wherein the PPDU comprises an extremely high throughput (EHT) PPDU, an ultra-high reliability (UHR) PPDU, or a UHR+ PPDU, and wherein the SIG field comprises a universal SIG (U-SIG) field of the PPDU.

40. The method of any of claims 37-38, wherein the PPDU comprises a high efficiency (HE) PPDU, and wherein the SIG field comprises an HE-SIG-A field of the PPDU.41 . The method of any of claims 37-40, wherein the SIG field indicates / comprises a BSS color field set to a first BSS color different than a second BSS color of the AP.

42. The method of any of claims 2-36, wherein determining that the PPDU comprises the inter-BSS PPDU comprises decoding one or more medium access control (MAC) protocol data unit (MPDU) of the PPDU,Docket No.: 24-3041 PCT and wherein the one or more MPDU indicates / comprises a first BSSID different than a second BSSID of the AP.

43. A method comprising: determining, by a station (STA), that a physical layer protocol data unit (PPDU) being received via a primary channel (PCH) comprises an inter-basic service set (inter-BSS) PPDU; decoding, by the STA, a delimiter of a medium access protocol (MAC) protocol data unit (MPDU) of the PPDU to determine a length of the MPDU; based on the length of the MPDU being larger than a threshold, switching, by the STA, from the PCH to a non-primary channel access (NPCA) PCH; and communicating, by the STA, with an access point (AP) on the NPCA PCH.

44. A method comprising: determining, by a station (STA), that a physical layer protocol data unit (PPDU) being received via a primary channel (PCH) comprises an inter-basic service set (inter-BSS) PPDU; and based on a length of a medium access protocol (MAC) protocol data unit (MPDU) of the PPDU being larger than a threshold, switching, by the STA, from the PCH to a non-primary channel access (NPCA) PCH.

45. The method of claim 2, wherein the MPDU comprises a first occurring MPDU of the PPDU.

46. The method of any of claims 2-3, further comprising decoding a delimiter of the MPDU to determine the length of the MPDU.

47. The method of claim 4, wherein the delimiter of the MPDU comprises an MPDU delimiter.

48. The method of any of claims 4-5, wherein the delimiter occurs before the MPDU in the PPDU.

49. The method of any of claims 4-6, wherein the length of the MPDU comprises an MPDU length.

50. The method of any of claims 2-7, wherein the switching from the PCH to the NPCA PCH comprises switching from the PCH to the NPCA PCH without decoding a MAC header of the MPDU.

51. The method of any of claims 2-8, wherein the switching from the PCH to the NPCA PCH comprises switching from the PCH to the NPCA PCH without decoding a frame body of the MPDU.

52. The method of any of claims 2-9, wherein the switching from the PCH to the NPCA PCH comprises switching from the PCH to the NPCA PCH without decoding the MPDU.

53. The method of any of claims 4-10, wherein the switching from the PCH to the NPCA PCH comprises switching from the PCH to the NPCA PCH after decoding the delimiter of the MPDU and before receiving a frequency checksum (FCS) field of the MPDU.

54. The method of any of claims 4-11 , wherein the switching from the PCH to the NPCA PCH comprises switching from the PCH to the NPCA PCH after decoding the delimiter of the MPDU and while receiving a frame body of the MPDU.Docket No.: 24-3041 PCT55. The method of any of claims 4-12, further comprising based on the length of the MPDU being less than or equal to the threshold, not switching, by the STA, from the PCH to the NPCA PCH right after decoding the delimiter of the MPDU.

56. The method of any of claims 4-12, further comprising based on the length of the MPDU being less than or equal to the threshold, decoding, by the STA, the MPDU after decoding the delimiter.

57. The method of claim 14, further comprising obtaining, by the STA, duration information from the MPDU.

58. The method of claim 15, wherein the MPDU comprises a duration field, and wherein the duration field comprises the duration information.

59. The method of claim 16, wherein a MAC header of the MPDU comprises the duration field.

60. The method of any of claims 15-17, wherein the duration information indicates a value for a network allocation vector (NAV) for a transmission comprising the PPDU.

61. The method of any of claims 15-17, wherein the duration information indicates a value for a transmission opportunity (TXOP) for a transmission comprising the PPDU.

62. The method of any of claims 2-19, wherein the MPDU comprises a MAC frame.

63. The method of any of claims 2-3, further comprising based on a failure to decode a delimiter of the MPDU, switching, by the STA, from the PCH to the NPCA PCH.

64. The method of claim 2, further comprising based on a failure to decode a delimiter of the MPDU, locating / determining, by the STA, a next MPDU delimiter occurring after the delimiter.

65. The method of any of claims 2-22, wherein the switching from the PCH to the NPCA PCH comprises operating on the NPCA PCH.

66. The method of any of claims 2-23, further comprising receiving, by the STA from an access point (AP), a first frame indicating: support, by the AP, a frame size-based NPCA switching operation; and / or enablement / disablement, by the AP, of the frame size-based NPCA switching operation.

67. The method of claim 24, wherein the first frame comprises a beacon frame, a fast initial link setup (FILS) discovery frame, a traffic indication map (TIM) broadcast frame, a broadcast probe response frame, a broadcast frame, a control frame, a management frame, an action frame, a quality of service (QoS) null frame, or a QoS data frame.

68. The method of any of claims 2-25, further comprising: transmitting, by the STA to an access point (AP), a second frame indicating: support, by the STA, of a frame size-based NPCA switching operation; and / or enablement / disablement, by the STA, of the frame size-based NPCA switching operation; and in response to the second frame, receiving, by the STA from the AP, a third frame indicating: support, by the AP, of the frame size-based NPCA switching operation; and / or enablement / disablement, by the AP, of the frame size-based NPCA switching operation.Docket No.: 24-3041 PCT69. The method of claim 26, wherein the second frame comprises an individually addressed probe request frame, association request frame, request frame, control frame, management frame, action frame, quality of service (QoS) null frame, or QoS data frame.

70. The method of claim 26, wherein the third frame comprises an individually addressed probe response frame, association response frame, response frame, control frame, management frame, action frame, quality of service (QoS) null frame, or QoS data frame.

71. The method of any of claims 2-28, further comprising receiving, by the STA from the AP, a fourth frame comprising the threshold.

72. The method of any of claims 2-29, wherein the threshold is recommended by the AP.

73. The method of any of claims 2-28, further comprising transmitting, by the STA to an access point (AP), a fifth frame comprising the threshold.

74. The method of claim 31 , wherein the threshold is recommended by the STA.

75. The method of any of claims 2-32, further comprising communicating, by the STA and during the length of the PPDU, with the AP on the NPCA PCH.

76. The method of any of claims 2-33, further comprising communicating, by the STA and during a duration information indicated in the PPDU, with the AP on the NPCA PCH.

77. The method of any of claims 2-34, further comprising switching, by the STA, from the NPCA PCH to the PCH before an end of the PPDU, an end of a network allocation vector (NAV) determined based on the PPDU, or an end of a transmit opportunity (TXOP) associated with the PPDU.

78. The method of any of claims 2-35, wherein determining that the PPDU comprises the inter-BSS PPDU comprises receiving the PPDU from a STA that does not belong to a basic service set (BSS) of the AP.

79. The method of any of claims 2-36, wherein determining that the PPDU comprises the inter-BSS PPDU comprises decoding a signal (SIG) field of the PPDU.

80. The method of claim 37, wherein the PPDU comprises a preamble part or a PHY header, and wherein the preamble part or the PHY header comprises the SIG field.81 . The method of any of claims 37-38, wherein the PPDU comprises an extremely high throughput (EHT) PPDU, an ultra-high reliability (UHR) PPDU, or a UHR+ PPDU, and wherein the SIG field comprises a universal SIG (U-SIG) field of the PPDU.

82. The method of any of claims 37-38, wherein the PPDU comprises a high efficiency (HE) PPDU, and wherein the SIG field comprises an HE-SIG-A field of the PPDU.

83. The method of any of claims 37-40, wherein the SIG field indicates / comprises a BSS color field set to a first BSS color different than a second BSS color of the AP.

84. The method of any of claims 2-36, wherein determining that the PPDU comprises the inter-BSS PPDU comprises decoding one or more medium access control (MAC) protocol data unit (MPDU) of the PPDU,Docket No.: 24-3041 PCT and wherein the one or more MPDU indicates / comprises a first BSSID different than a second BSSID of the AP.

85. 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 1-84.

86. 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 1-84.

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