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

Abstract

An access point (AP) detects via a primary channel (PCH) a non-high throughput (non-HT) physical layer protocol data unit (PPDU) and obtains a first network allocation vector (NAV) duration from a medium access protocol (MAC) frame of the non-HT PPDU. After determining that the non-HT PPDU comprises an inter-basic service set (inter-BSS) PPDU, the AP switches from the PCH to a non-primary channel access (NPCA) PCH and transmits to a station (STA), via the NPCA PCH, a first frame indicating the first NAV duration. The AP receives from the STA a second frame indicating a second NAV duration, obtained by the STA for the MAC frame of the non-HT PPDU. Based on the first NAV duration being equal to the second NAV duration, the AP communicates, during the first NAV duration, with the STA on the NPCA PCH.

Description

Docket No.: 24-3042PCTTITLEFRAME HEADER-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 / 700,811 , filed September30, 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 illustrates an example non-high throughput (non-HT) physical layer protocol data unit (PPDU) format.

[0013] FIG. 11 is an example that illustrates non-primary channel access (NPCA) operation.

[0014] FIG. 12 illustrates virtual and physical carrier sense (CS) functions associated with primary and secondary channels for NPCA operation and non-NPCA operation.

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

[0016] FIG. 14 illustrates an inefficiency that may arise in the NPCA operation of FIG. 13.

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

[0018] FIG. 16 shows another example of the example NPCA operation illustrated in FIG. 15.

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

[0020] FIG. 18 shows an example that illustrates an example frame exchange according to an embodiment.

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

[0022] FIG. 20 illustrates another example process according to an embodiment.DETAILED DESCRIPTIONDocket No.: 24-3042PCT

[0023] 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.

[0024] 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.

[0025] 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.

[0026] 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.: 24-3042PCT 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.

[0027] 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.

[0028] 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.

[0029] 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

[0030] 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.: 24-3042PCT 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.

[0031] FIG. 1 illustrates example wireless communication networks in which embodiments of the present disclosure may be implemented.

[0032] 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.

[0033] 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.

[0034] 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).

[0035] 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.

[0036] 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).

[0037] 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.: 24-3042PCT 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.

[0038] 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.

[0039] 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.

[0040] 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 the default channel for a BSS. An AP of the BSS uses the primary channel to transmit management frames, thereby ensuring that all STAs in the BSS (regardless of channel bonding support) can receive the management frames.

[0041] 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.: 24-3042PCT

[0042] 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.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] As shown in FIG. 3, a MAC frame includes a MAC header, a variable length frame body, and a frame check sequence (FCS).

[0047] 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.

[0048] 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.

[0049] 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.

[0050] 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.: 24-3042PCT 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.

[0051] 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.

[0052] 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.

[0053] 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.

[0054] The power management subfield is used to indicate the power management mode of a STA.

[0055] 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.

[0056] The protected frame subfield is set to 1 if the frame body field contains information that has been processed by a cryptographic encapsulation algorithm.

[0057] The +HTC subfield indicates that the MAC frame contains an HT control field.

[0058] 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.

[0059] 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.: 24-3042PCT 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.

[0060] 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

[0061] 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.

[0062] 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.

[0063] 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.

[0064] 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.

[0065] 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.

[0066] 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.

[0067] 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.

[0068] 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.: 24-3042PCTDuration 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).

[0069] 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.

[0070] 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.

[0071] 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.

[0072] 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.

[0073] 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.

[0074] 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.: 24-3042PCT

[0075] 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.

[0076] 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”).

[0077] 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.

[0078] 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.

[0079] 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.: 24-3042PCTRTS 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.

[0080] 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.

[0081] 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.

[0082] 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.

[0083] 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).

[0084] 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.

[0085] 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.: 24-3042PCT

[0086] 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.

[0087] 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.

[0088] 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.

[0089] 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.

[0090] 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.: 24-3042PCT 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.

[0091] 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.

[0092] 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.

[0093] 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.

[0094] 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.

[0095] 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.: 24-3042PCT

[0096] 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

[0097] 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.

[0098] 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.

[0099] 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.

[0100] FIG. 10 illustrates an example non-HT PPDU format. As shown in FIG. 10, the non-HT PPDU format may include a PHY preamble, a PHY header, a PSDU, tail bits, and pad bits. The PHY preamble may include 12 OFDM symbols.

[0101] The PHY header includes a SIGNAL field and a SERVICE field. The SIGNAL field includes a RATE field, a reserved bit, a LENGTH field, a parity bit, and tail bits. The tail bits of the SIGNAL field enable decoding of the RATE and LENGTH fields immediately after the reception of the tail bits. The SIGNAL field may constitute a single OFDM symbol. The SIGNAL field may be transmitted using the most robust combination of Binary Phase Shift Keying (BPSK) modulation and a coding rate of R =1 / 2.

[0102] The SERVICE field of the PHY header and the PSDU (with 6 zero tail bits and pad bits appended), denoted as DATA field, are transmitted at the data rate described in the RATE field of the PHY header. The DATA field may constitute multiple OFDM symbols. The RATE and LENGTH fields are required for decoding the DATA field.

[0103] It is envisioned in future IEEE 802.11 standards that a STA (AP STA or non-AP STA) may access a non-primary channel to communicate with another STA. Such operation may be referred to as non-primary channel access (NPCA) operation. Specifically, in addition to a default primary channel (which is used by all STAs in the BSS and via which the AP transmits management frames), the STA may have one or moreDocket No.: 24-3042PCT 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. 11 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. 11 , 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. 11 For example, the NPCA primary channel may correspond to SCH1 .

[0104] In an implementation, as shown in FIG. 12, 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. 11 , 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).

[0105] In contrast, as shown in FIG. 12, 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 11 , 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.

[0106] 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”).

[0107] 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 synchronizationDocket No.: 24-3042PCT 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.

[0108] FIG. 13 shows an example 1300 that illustrates an NPCA operation. As shown in FIG. 13, example 1300 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).

[0109] Example 1300 may begin with the AP transmitting a frame 1302 on the PCH. Frame 1302 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 1302 may be a management frame, such as a beacon frame, for example.

[0110] Subsequently, while the AP and STA operate on the PCH, transmission of a frame 1304 from an OBSS may begin on the PCH. The AP and the STA may detect frame 1304 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 1304 on the PCH. Frame 1304 may indicate a transmission (of one or more frames including frame 1304) on the PCH. A duration of the transmission on the PCH may be provided by a duration field of frame 1304, a transmission opportunity (TXOP) duration field of an OBSS PPDU comprising frame 1304, 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).

[0111] 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.

[0112] 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 inDocket No.: 24-3042PCT frame 1302). In example 1300, 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 1306 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 1306 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. 13) on the NPCA PCH.

[0113] FIG. 14 shows an example 1400 that illustrates an inefficiency that may arise in the NPCA operation of FIG. 13. 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.

[0114] 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 non-High Throughput (HT) PPDU, 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 (including checking the FCS for each decoded 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.Docket No.: 24-3042PCT

[0115] 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 NAV 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.

[0116] Embodiments of the present disclosure, as further described below, address the above-described problem of existing technologies. In an aspect, an AP (or a STA) receives a PPDU via a PCH. After determining that the PPDU is an inter-BSS PPDU and obtaining a first duration (OBSS NAV duration) from a MAC frame (MPDU) of the PPDU, the AP (or STA) switches from the PCH to an NPCA PCH. The AP (or STA) may communicate with a STA (or an AP) via the NPCA PCH based on the first duration. In an embodiment, the AP (or STA) decodes a portion of the MAC frame of the PPDU. In an embodiment, the portion of the MAC frame does not include a frame body or an FCS field of the MAC frame. In an embodiment, the portion of the MAC frame may comprise a portion of a MAC header of the MAC frame. In an embodiment, the portion of the MAC header does not include one or more fields (e.g., Address 3, Sequence Control, Address 4, QoS Control, or HT Control) of the MAC header. As such, the AP (or STA) may switch to the NPCA PCH earlier than in existing NPCA operation, particularly when the MAC frame is relatively long (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 (or STA) and the STA (or AP) on the NPCA PCH after the AP (or STA) and STA (or AP) switch to the NPCA PCH. In an embodiment, after switching to the NPCA PCH, the AP (or STA) may transmit a first frame indicating the first duration obtained from the MAC frame of the PPDU and may receive, from the STA (or AP), a second frame indicating a second duration obtained from the MAC of the PPDU by the STA (or AP). This frame exchange allows the AP (or STA) toDocket No.: 24-3042PCT determine whether the first duration obtained from the MAC frame (e.g., without decoding the entire MAC frame) of the PPDU is correct and the duration of operation on the NPCA PCH.

[0117] FIG. 15 shows an example 1500 that illustrates an example NPCA operation according to an embodiment. Example 1500 is provided for the purpose of illustration only and is not limiting of embodiments. As shown in FIG. 15, example 1500 includes an AP 1502 and a STA 1504. AP 1502 and STA 1504 belong to the same BSS. STA 1504 may be associated with AP 1502. AP 1502 and STA 1504 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).

[0118] AP 1502 and STA 1504 may each support an NPCA (switching) mode (or NPCA operation mode). According to the NPCA mode, AP 1502 (or STA 1504) may be configured, after receiving a PPDU (e.g., non- HT (dup) PPDU) being received via the PCH, to decode (process, parse, or read) a portion of a MAC frame (or MPDU) of the PPDU to determine an OBSS NAV duration (or TXOP duration) and / or determine that the PPDU comprises an inter-BSS (or OBSS) PPDU. In an embodiment, according to the NPCA mode, AP 1502 (or STA 1504) 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 obtain an OBSS NAV duration from a preamble or a PHY header of the PPDU), to decode (process, parse, or read) a portion of a MAC frame (or MPDU) of the PPDU to determine an OBSS NAV duration (or TXOP duration). As further explained below, AP 1502 (or STA 1504) may determine that the PPDU comprises an inter-BSS PPDU based on one or more fields of the preamble or PHY header of the PPDU or one or more fields of the MAC frame of the PPDU. The MAC frame may correspond to a first occurring MPDU (of multiple MPDUs) of the PPDU or may be the only MPDU contained in the PPDU. In an embodiment, the decoded portion of the MAC frame includes one or more fields of a MAC header of the MAC frame. In an embodiment, the one or more fields include all fields of the MAC header. In another embodiment, the one or more fields include one or more of: a frame control (FC) field, a duration field, and one or more address fields of the MAC header. In an embodiment, the duration field indicates the OBSS NAV duration (or TXOP duration). In an embodiment, AP 1502 (or STA 1504) may be configured to determine whether the PPDU comprises a non-HT PPDU and to decode the portion of the MAC frame based on determining that the PPDU comprises a non-HT PPDU.

[0119] In an embodiment, AP 1502 (or STA 1504) may be configured to switch from the PCH to the NPCA PCH after determining the OBSS NAV duration (or TXOP duration) from the decoded portion of the MAC frame of the PPDU. In an embodiment, AP 1502 (or STA 1504) may be configured to switch from the PCH to the NPCA PCH immediately after processing the decoded portion of the MAC frame of the PPDU. In an embodiment, AP 1502 (or STA 1504) switches from the PCH to the NPCA PCH without decoding a frame body of the MAC frame. In another embodiment, alternatively or additionally, AP 1502 (or STA 1504) switches from the PCH to the NPCA PCH without computing an FCS field of the MAC frame. In an embodiment, AP 1502 (or STA 1504) switches from the PCH to the NPCA PCH without decoding a portion of a MAC headerDocket No.: 24-3042PCT of the MAC frame. In an embodiment, AP 1502 (or STA 1504) switches from the PCH to the NPCA PCH without processing (detecting, reading, parsing, decoding, or receiving) a remaining portion, after the decoded portion, of the MAC frame. In an embodiment, the remaining portion comprises at least one of: a frame body and an FCS field of the MAC frame. In an embodiment, the remaining portion comprises one or more fields of Address 3, Sequence Control, Address 4, QoS Control, and HT Control of a MAC header of the MAC frame. In an embodiment, switching from the PCH to the NPCA PCH comprises operating (parking / camping) on the NPCA PCH.

[0120] As mentioned above, in an embodiment, the MAC frame may be the first occurring MPDU of the PPDU. In an embodiment, if AP 1502 (or STA 1504) fails to obtain the OBSS NAV duration (or TXOP duration) from the first occurring MPDU (e.g., AP 1502 (or STA 1504) fails to decode the first occurring MPDU or the first occurring MPDU does not indicate the OBSS NAV duration (or TXOP duration)), AP 1502 (or STA 1504) may locate a next MAC frame (or MPDU) of the PPDU and to repeat the process described above with respect to the next MAC frame. In another embodiment, if AP 1502 (or STA 1504) fails to obtain the OBSS NAV duration (or TXOP duration) from the first occurring MPDU (e.g., AP 1502 (or STA 1504) fails to decode the first occurring MPDU or the first occurring MPDU does not indicate the OBSS NAV duration (or TXOP duration)), AP 1502 (or STA 1504) may be configured to switch from the PCH to the NPCA PCH (e.g., without trying to locate a next MAC frame).

[0121] In an embodiment, AP 1502 (or STA 1504) 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 1502. In an embodiment, AP 1502 (or STA 1504) 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 1502 (or STA 1504) 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 1502 (or STA 1504) 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 1502. 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+ (e.g., beyond UHR) PPDU. The SIG field may be an HE-SIG-A field, for example when the PPDU comprises a high efficiency (HE) PPDU. The SIG field may be an VHT-SIG-A field, for example when the PPDU comprises a VHT PPDU.

[0122] In another embodiment, AP 1502 (or STA 1504) may be configured to determine that the PPDU comprises an inter-BSS PPDU based on the MAC frame of the PPDU, e.g., based on decoding (processing, detecting, reading, receiving, or parsing) one or more fields of the MAC frame of and the one or more fields indicating / comprising a first BSSID different than a second BSSID of AP 1502. In an embodiment, the one orDocket No.: 24-3042PCT more fields of the MAC frame include one or more address fields of a MAC header of the MAC frame. In an embodiment, the one or more address fields include at least one of: an “Address 1” field, an “Address 2” field, an “Address 3” field, and an “Address 4” field of the MAC header. For example, AP 1502 (or STA 1504) may be configured to determine that the PPDU comprises an inter-BSS PPDU based on the MAC frame, based on determining that the PPDU is a non-HT PPDU (which does not indicate a BSS color or BSSID in a preamble or PHY header of the PPDU).

[0123] In an embodiment, after switching to the NPCA PCH, AP 1502 (or STA 1504) may be configured to transmit a first frame indicating the OBSS NAV duration (or TXOP duration) obtained based on the MAC frame of the PPDU. In an embodiment, AP 1502 (or STA 1504) may be configured to receive from STA 1504 (AP 1502) a second frame indicating an OBSS NAV duration (or TXOP duration), obtained by STA 1504 (AP 1502), based on the MAC frame of the PPDU. In an embodiment, the receiving of the second frame may be in response to the transmitting of the first frame. In another embodiment, the transmitting of the first frame may be in response to the receiving of the second frame. In an embodiment, the first frame may comprise an initial control frame (ICF), a request-to-send (RTS) frame, a multi-user (MU)-RTS frame, a trigger frame, a BlockAckRequest (BAR) frame (including multi-TID BAR frame), a buffer status report poll (BSRP) Trigger frame, a control frame, a quality of service (QoS) null frame, a management frame, or an action frame. In an embodiment, the second frame may comprise an initial control response frame (ICR), a clear-to-send (RTS) frame, a modified CTS frame, a trigger frame, a BlockAck (BA) frame (including multi-STA BA frame), a BSR frame, a control frame, a quality of service (QoS) null frame, a management frame, or an action frame.

[0124] In an embodiment, AP 1502 (or STA 1504) may be configured, based on the OBSS NAV duration (or TXOP duration) indicated by AP 1502 (STA 1504) being equal to the OBSS NAV duration (or TXOP duration) indicated by STA 1504 (AP 1502), to operate (park / camp) on the NPCA PCH during (or within) the OBSS NAV duration (or TXOP duration) indicated by AP 1502 (or STA 1504). In an embodiment, AP 1502 (or STA 1504) may be further configured, based on the OBSS NAV duration (or TXOP duration) indicated by AP 1502 (STA 1504) being equal to the OBSS NAV duration (or TXOP duration) indicated by STA 1504 (AP 1502), to switch (return) from the NPCA PCH to the PCH before an end of (or within) the OBSS NAV duration (or TXOP duration) indicated by AP 1502 (or STA 1504). Conversely, AP 1502 (or STA 1504) may be configured, based on the OBSS NAV duration (or TXOP duration) indicated by AP 1502 (STA 1504) being not equal to the OBSS NAV duration (or TXOP duration) indicated by STA 1504 (AP 1502), to operate (park / camp) on the NPCA PCH during (or within) a length (or duration) of the PPDU. In an embodiment, AP 1502 (or STA 1504) may be further configured, based on the OBSS NAV duration (or TXOP duration) indicated by AP 1502 (STA 1504) being not equal to the OBSS NAV duration (or TXOP duration) indicated by STA 1504 (AP 1502), to switch (return) from the NPCA PCH to the PCH before an end of the PPDU (within the length / duration of the PPDU).Docket No.: 24-3042PCT

[0125] Returning to FIG. 15, example 1500 begins with a PPDU 1506 being transmitted on the PCH. PPDU 1506 may be transmitted by a STA that does not belong to the BSS of APs 1502 and STA 1504. PPDU 1506 may comprise a MAC frame comprising a MAC header, a frame body, and an FCS field. PPDU 1506 is therefore an inter-BSS (or OBSS) PPDU for APs 1502 and STA 1504. As AP 1502 and STA 1504 operate on the PCH, AP 1502 and / or STA 1504 may (in parallel) detect / sense the transmission of PPDU 1506 and begin to decode (read, detect, process, parse, or receive) PPDU 1506. In an example, AP 1502 and / or STA 1504 may decode (read, detect, process, parse, or receive) a PHY identifier field of PPDU 1506, which allows AP 1502 and STA 1504 to determine a PPDU type of PPDU 1506.

[0126] Next, in an embodiment, AP 1502 and / or STA 1504 may decode (read, detect, process, parse, or receive) a preamble / PHY header of PPDU 1506 to determine if PPDU 1506 is an inter-BSS PPDU. As described above, AP 1502 and / or STA 1504 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 1506 is an inter-BSS PPDU. In example 1500, AP 1502 and / or STA 1504 may determine that PPDU 1506 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 1502.

[0127] In another embodiment, alternatively or additionally, AP 1502 and / or STA 1504 may decode (read, detect, process, parse, or receive) the MAC frame (or MPDU) (or a portion of the MAC header of the MAC frame) of PPDU 1506 to determine if PPDU 1506 is an inter-BSS PPDU. The MAC frame may correspond to a first occurring MPDU of PPDU 1506 or may be a single MPDU of PPDU 1506. In an embodiment, AP 1502 and / or STA 1504 may be configured to decode (read, detect, process, parse, or receive) the MAC frame of PPDU 1506 to determine if PPDU 1506 is an inter-BSS PPDU based on failing to determine whether PPDU 1506 is an inter-BSS PPDU based on reading / decoding the preamble / PHY header of PPDU 1506. As described above, AP 1502 and / or STA 1504 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 MAC frame to determine whether the BSSID field indicates a MAC address different than a MAC address of AP 1502.

[0128] Continuing with example 1500, after determining that PPDU 1506 is an inter-BSS PPDU (and, optionally, after failing to obtain an OBSS NAV duration from a preamble or a PHY header of PPDU 1506), AP 1502 and / or STA 1504 may decode (process, parse, or read) a portion of the MAC frame contained in PPDU 1506 to determine an OBSS NAV duration (or TXOP duration). In example 1500, the decoded portion of the MAC frame includes one or more fields of the MAC header of the MAC frame. In an embodiment, the one or more fields include all fields of the MAC header. In another embodiment, the one or more fields include one or more of: a frame control (FC) field, a duration field, and one or more address fields of the MAC header. In an embodiment, AP 1502 and / or STA 1504 does not decode the frame body of the MAC frame. In an embodiment, AP 1502 and / or STA 1504 does not decode the FCS field of the MAC frame. In an embodiment,Docket No.: 24-3042PCTAP 1502 and / or STA 1504 may not decode one or more fields (e.g., Address 3, Sequence Control, Address 4, QoS Control, or HT Control) of a MAC header of the MAC frame. As such, AP 1502 and / or STA 1504 may not be able to determine whether the decoded portion of the MAC frame was decoded correctly (and whether the determined OBSS NAV duration is correct).

[0129] After determining the OBSS NAV duration (or TXOP duration) based on the MAC header of the MAC frame contained in PPDU 1506, AP 1502 and / or STA 1504 may switch from the PCH to the NPCA PCH. In an embodiment, AP 1502 and STA 1504 may be configured to switch to the NPCA PCH at the same switching time. In example 1500, AP 1502 and STA 1504 switch from the PCH to the NPCA PCH after decoding the MAC header of the MAC frame contained in PPDU 1506. The switching time may correspond to the time that AP 1502 and STA 1504 finish decoding / reading the MAC header. However, other switching times may also be configured or negotiated / agreed between AP 1502 and STA 1504. In example 1500, AP 1502 and STA 1504 do not decode (process, parse, or read) a frame body or an FCS field of the MAC frame.

[0130] Subsequently, AP 1502 may access the NPCA PCH and transmit a frame 1508 to STA 1504. In an embodiment, frame 1508 indicates a first duration corresponding to the OBSS NAV duration (or TXOP duration) obtained / determined by AP 1502 based on the MAC frame (or a portion of the MAC header of the MAC frame) contained in PPDU 1506. In example 1500, AP 1502 determines the OBSS NAV duration (or TXOP duration) as being equal to "X” (where X represents a time duration, e.g., in microseconds) and thus indicates the value “X” for the first duration in frame 1508. As shown in FIG. 15, frame 1508 may be transmitted via a bandwidth that comprises the NPCA PCH. For example, frame 1508 may be transmitted via the NPCH PCH and SCH2. Frame 1508 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.

[0131] STA 1504 may respond to frame 1508 from AP 1502 by transmitting a frame 1510 to AP 1502. In an embodiment, frame 1510 indicates a second duration corresponding to the OBSS NAV duration (or TXOP duration) obtained / determined by STA 1504 based on the MAC frame (or a portion of the MAC header of the MAC frame) contained in PPDU 1506. In example 1500, STA 1504 determines the OBSS NAV duration (or TXOP duration) as being equal to “X” and thus indicates the value “X” for the second duration in frame 1510. As shown in FIG. 15, frame 1510 may be transmitted via a bandwidth that comprises the NPCA PCH. For example, frame 1510 may be transmitted via the NPCH PCH and SCH2. Frame 1510 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.Docket No.: 24-3042PCT

[0132] In an embodiment, based on receiving frame 1508 from AP 1502 indicating the value “X” for the first duration, STA 1504 determines that AP 1502 computed / determined the same value as STA 1504 for the OBSS NAV duration. In an embodiment, based on this determination, STA 1504 may determine that the second duration (corresponding to the OBSS NAV duration (TXOP duration) that STA 1504 obtained based on the MAC frame of PPDU 1506) is correct (or that STA 1504 correctly decoded the decoded portion of the MAC frame of PPDU 1506). STA 1504 may thus determine to operate on the NPCA PCH for the OBSS NAV duration that STA 1504 obtained based on the MAC frame (STA 1504 may return to the PCH before an end of the OBSS NAV duration). Similarly, based on receiving frame 1510 from STA 1504 indicating the value “X” for the second duration, AP 1502 determines that STA 1504 computed / determined the same value as AP 1502 for the OBSS NAV duration. In an embodiment, based on this determination, AP 1502 may determine that the first duration (corresponding to the OBSS NAV duration (TXOP duration) that AP 1502 obtained based on the MAC frame of PPDU 1506) is correct (or that AP 1502 correctly decoded the decoded portion of the MAC frame of PPDU 1506). AP 1502 may thus determine to operate on the NPCA PCH for the OBSS NAV duration that AP 1502 obtained based on the MAC frame (AP 1502 may return to the PCH before an end of the OBSS NAV duration).

[0133] In another example (not shown in FIG. 15), the operation performed by AP 1502, described above, may be performed by STA 1504, and vice versa. That is, frame 1508 may be transmitted by STA 1504 (instead of AP 1502) and frame 1510 may be transmitted by AP 1502 (instead of STA 1504).

[0134] In accordance with the above described operation, in example 1500, AP 1502 and STA 1504 may exchange one or more frames while operating, for the OBSS NAV duration, on the NPCA PCH. For example, AP 1502 may transmit a frame 1512 to STA 1504. Frame 1512 may comprise a data frame, a management frame, or an action frame, for example. STA 1504 may respond to frame 1512 by transmitting a frame 1514 to AP 1502. Frame 1514 may comprise an immediate response frame, such as an Ack frame or a BA frame. Subsequently, AP 1502 may transmit a further frame 1516 to STA 1504. Frame 1516 may comprise a data frame, a management frame, or an action frame, for example. STA 1504 may respond to frame 1516 by transmitting a frame 1518 to AP 1502. AP 1502 and STA 1504 may finish communicating on the NPCA PCH and return to the PCH before an end of the OBSS NAV duration. As such, communication between AP 1502 and STA 1504 may occur on the NPCA PCH for a prolonged period of time. This allows for buffered traffic between AP 1502 and STA 1504 to be transmitted with minimal delay and avoids NPCA PCH resources from being wasted.

[0135] FIG. 16 shows another example 1600 of the NPCA operation described with reference to FIG. 15 above. Example 1600 is provided for the purpose of illustration only and is not limiting of embodiments. As in example 1500, example 1600 also includes AP 1502 and STA 1504 described above. AP 1502 and STA 1504 may be configured as discussed above with respect to FIG. 15.Docket No.: 24-3042PCT

[0136] Example 1600 begins with a PPDU 1602 being transmitted on the PCH. PPDU 1602 may comprise a MAC frame comprising a MAC header, a frame body, and an FCS field. The MAC frame may correspond to a first occurring MPDU (of multiple MPDUs) of PPDU 1602 or may be the only MPDU contained in PPDU 1602. PPDU 1602 may be transmitted by a STA that does not belong to the BSS of APs 1502 and STA 1504. PPDU 1602 is therefore an inter-BSS (or OBSS) PPDU for APs 1502 and STA 1504. As AP 1502 and STA 1504 operate on the PCH, AP 1502 and / or STA 1504 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 1502 and / or STA 1504 may decode (read, detect, process, parse, or receive) a PHY identifier field of PPDU 1602, which allows AP 1502 and STA 1504 to determine a PPDU type of PPDU 1602.

[0137] Next, as described above, AP 1502 and / or STA 1504 may decode (read, detect, process, parse, or receive) a preamble / PHY header of PPDU 1602 to determine if PPDU 1602 is an inter-BSS PPDU. Alternatively, or additionally, AP 1502 and / or STA 1504 may decode (read, detect, process, parse, or receive) the MAC frame (or MPDU) (or a portion of the MAC header of the MAC frame) of PPDU 1602 to determine if PPDU 1602 is an inter-BSS PPDU.

[0138] 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 1502 and / or STA 1504 may decode (process, parse, or read) a portion of the MAC frame contained in PPDU 1602 to determine an OBSS NAV duration (or TXOP duration). In example 1600, the decoded portion of the MAC frame includes one or more fields of the MAC header of the MAC frame. In an embodiment, the one or more fields include all fields of the MAC header. In another embodiment, the one or more fields include one or more of: a frame control (FC) field, a duration field, and one or more address fields of the MAC header. In an embodiment, AP 1502 and / or STA 1504 does not decode the frame body of the MAC frame. In an embodiment, AP 1502 and / or STA 1504 does not decode the FCS field of the MAC frame. In an embodiment, AP 1502 and / or STA 1504 may not decode one or more fields (e.g., Address 3, Sequence Control, Address 4, QoS Control, or HT Control) of a MAC header of the MAC frame. As such, AP 1502 and / or STA 1504 may not be able to determine whether the decoded portion of the MAC frame was decoded correctly (and whether the determined OBSS NAV duration is correct).

[0139] After determining the OBSS NAV duration (or TXOP duration) based on the MAC header of the MAC frame contained in PPDU 1602, AP 1502 and / or STA 1504 may switch from the PCH to the NPCA PCH. In an embodiment, AP 1502 and STA 1504 may be configured to switch to the NPCA PCH at the same switching time. In example 1600, AP 1502 and STA 1504 switch from the PCH to the NPCA PCH after decoding the MAC header of the MAC frame contained in PPDU 1602. The switching time may correspond to the time that AP 1502 and STA 1504 finish decoding / reading the MAC header. However, other switching times may also be configured or negotiated / agreed between AP 1502 and STA 1504. In example 1600, AP 1502 and STA 1504 do not decode (process, parse, or read) a frame body or an FCS field of the MAC frame.Docket No.: 24-3042PCT

[0140] Subsequently, AP 1502 may access the NPCA PCH and transmit a frame 1604 to STA 1504. In an embodiment, frame 1604 indicates a first duration corresponding to the OBSS NAV duration (or TXOP duration) obtained / determined by AP 1502 based on the MAC frame (or a portion of the MAC header of the MAC frame) contained in PPDU 1602. In example 1600, AP 1502 determines the OBSS NAV duration (or TXOP duration) as being equal to “X" and thus indicates the value “X" for the first duration in frame 1604. 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 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.

[0141] STA 1504 may respond to frame 1604 from AP 1502 by transmitting a frame 1606 to AP 1502. In an embodiment, frame 1606 indicates a second duration corresponding to the OBSS NAV duration (or TXOP duration) obtained / determined by STA 1504 based on the MAC frame (or a portion of the MAC header of the MAC frame) contained in PPDU 1506. In example 1600, STA 1504 determines the OBSS NAV duration (or TXOP duration) as being equal to “Y” (where Y represents a time duration, e.g., in microseconds) and thus indicates the value “Y” for the second duration in frame 1606. As shown in FIG. 16, frame 1606 may be transmitted via a bandwidth that comprises the NPCA PCH. For example, frame 1606 may be transmitted via the NPCH PCH and SCH2. 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.

[0142] In an embodiment, based on receiving frame 1604 from AP 1502 indicating the value “X" for the first duration, STA 1504 determines that AP 1502 computed / determined a different value than STA 1504 for the OBSS NAV duration. In an embodiment, based on this determination, STA 1504 may determine that the second duration (corresponding to the OBSS NAV duration (TXOP duration) that STA 1504 obtained based on the MAC frame of PPDU 1602) may be incorrect (or that STA 1504 incorrectly decoded the decoded portion of the MAC frame of PPDU 1602). STA 1504 may thus determine to operate on the NPCA PCH for the duration of PPDU 1602 (STA 1504 may return to the PCH before an end of PPDU 1602). Similarly, based on receiving frame 1606 from STA 1504 indicating the value “Y” for the second duration, AP 1502 determines that STA 1504 computed / determined a different value than AP 1502 for the OBSS NAV duration. In an embodiment, based on this determination, AP 1502 may determine that the first duration (corresponding to the OBSS NAV duration (TXOP duration) that AP 1502 obtained based on the MAC frame of PPDU 1506) may be incorrect (or that AP 1502 incorrectly decoded the decoded portion of the MAC frame of PPDU 1602). AP 1502 may thus determine (like STA 1504) to operate on the NPCA PCH for the duration of PPDU 1602 (STA 1504 may return to the PCH before an end of PPDU 1602).Docket No.: 24-3042PCT

[0143] In another example (not shown in FIG. 16), the operation performed by AP 1502, described above, may be performed by STA 1504, and vice versa. That is, frame 1604 may be transmitted by STA 1504 (instead of AP 1502) and frame 1606 may be transmitted by AP 1502 (instead of STA 1504).

[0144] In accordance with the above described operation, in example 1600, AP 1502 and STA 1504 may exchange one or more frames while operating, for duration of PPDU 1602, on the NPCA PCH. For example, AP 1502 may transmit a frame 1608 to STA 1504. Frame 1608 may comprise a data frame, a management frame, or an action frame, for example. STA 1504 may respond to frame 1608 by transmitting a frame 1610 to AP 1502. Frame 1610 may comprise an immediate response frame, such as an Ack frame or a BA frame. AP 1502 and STA 1504 may finish communicating on the NPCA PCH and return to the PCH before an end of PPDU 1602. As such, communication between AP 1502 and STA 1504 may occur on the NPCA PCH, albeit for a shorter time period, allowing some of the buffered traffic between AP 1502 and STA 1504 to be transmitted with minimal delay and avoiding NPCA PCH resources from being wasted during the transmission time of PPDU 1602.

[0145] FIG. 17 shows an example 1700 that illustrates an example NPCA operation according to an embodiment. Example 1700 is provided for the purpose of illustration only and is not limiting of embodiments. As shown in FIG. 17, example 1700 includes an AP 1702 and a STA 1704. AP 1702 and STA 1704 belong to the same BSS. STA 1704 may be associated with AP 1702. AP 1702 and STA 1704 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).

[0146] AP 1702 and STA 1704 may each support an NPCA (switching) mode (or NPCA operation mode). According to the NPCA mode, AP 1702 (or STA 1704) 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 obtain an OBSS NAV duration from a preamble or a PHY header of the PPDU), to decode (process, parse, or read) a portion of a MAC frame (or MPDU) of the PPDU to determine an OBSS NAV duration (or TXOP duration). As further explained below, AP 1702 (or STA 1704) may determine that the PPDU comprises an inter-BSS PPDU based on one or more fields of the preamble or PHY header of the PPDU or one or more fields of the MAC frame of the PPDU. The MAC frame may correspond to a first occurring MPDU (of multiple MPDUs) of the PPDU or may be the only MPDU contained in the PPDU. In an embodiment, the decoded portion of the MAC frame includes one or more fields of a MAC header of the MAC frame. In an embodiment, the one or more fields include all fields of the MAC header. In another embodiment, the one or more fields include one or more of: a frame control (FC) field, a duration field, and one or more address fields of the MAC header. In an embodiment, the duration field indicates the OBSS NAV duration (or TXOP duration). In an embodiment, AP 1702 (or STA 1704) may be configured to determine whether the PPDU comprises a non-HT PPDU and to decode the portion of the MAC frame based on determining that the PPDU comprises a non-HT PPDU.Docket No.: 24-3042PCT

[0147] In an embodiment, AP 1702 (or STA 1704) may be configured to switch from the PCH to the NPCA PCH after determining the OBSS NAV duration (or TXOP duration) from the decoded portion of the MAC frame of the PPDU. In an embodiment, AP 1702 (or STA 1704) may be configured to switch from the PCH to the NPCA PCH immediately after processing the decoded portion of the MAC frame of the PPDU. In an embodiment, AP 1702 (or STA 1704) switches from the PCH to the NPCA PCH without decoding a frame body of the MAC frame. In another embodiment, alternatively or additionally, AP 1702 (or STA 1704) switches from the PCH to the NPCA PCH without computing an FCS field of the MAC frame. In an embodiment, AP 1702 (or STA 1704) switches from the PCH to the NPCA PCH without processing (detecting, reading, parsing, decoding, or receiving) a remaining portion, after the decoded portion, of the MAC frame. In an embodiment, the remaining portion comprises at least one of: a frame body and an FCS field of the MAC frame. In an embodiment, the remaining portion comprises one or more fields of Address 3, Sequence Control , Address 4, QoS Control, and HT Control of MAC header of the MAC frame. In an embodiment, switching from the PCH to the NPCA PCH comprises operating (parking / camping) on the NPCA PCH.

[0148] As mentioned above, in an embodiment, the MAC frame may be the first occurring MPDU of the PPDU. In an embodiment, if AP 1702 (or STA 1704) fails to obtain the OBSS NAV duration (or TXOP duration) from the first occurring MPDU (e.g., AP 1702 (or STA 1704) fails to decode the first occurring MPDU or the first occurring MPDU does not indicate the OBSS NAV duration (or TXOP duration), AP 1702 (or STA 1704) may locate a next MAC frame (or MPDU) of the PPDU and to repeat the process described above with respect to the next MAC frame. In another embodiment, if AP 1702 (or STA 1704) fails to obtain the OBSS NAV duration (or TXOP duration) from the first occurring MPDU (e.g., AP 1702 (or STA 1704) fails to decode the first occurring MPDU or the first occurring MPDU does not indicate the OBSS NAV duration (or TXOP duration)), AP 1702 (or STA 1704) may be configured to switch from the PCH to the NPCA PCH (e.g., without trying to locate a next MAC frame).

[0149] In an embodiment, AP 1702 (or STA 1704) 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 1702. In an embodiment, AP 1702 (or STA 1704) 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 1702 (or STA 1704) 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 1702 (or STA 1704) 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 1702. 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)Docket No.: 24-3042PCTPPDU , 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.

[0150] In another embodiment, AP 1702 (or STA 1704) may be configured to determine that the PPDU comprises an inter-BSS PPDU based on the MAC frame of the PPDU, e.g., based on decoding (processing, detecting, reading, receiving, or parsing) one or more fields of the MAC frame of and the one or more fields indicating / comprising a first BSSID different than a second BSSID of AP 1702. In an embodiment, the one or more fields of the MAC frame include one or more address fields of a MAC header of the MAC frame. In an embodiment, the one or more address fields include at least one of: an “Address 1” field, an “Address 2” field, an “Address 3" field, and an “Address 4” field of the MAC header. For example, AP 1702 (or STA 1704) may be configured to determine that the PPDU comprises an inter-BSS PPDU based on the MAC frame, based on determining that the PPDU is a non-HT PPDU (which does not indicate a BSS color or BSSID in a preamble or PHY header of the PPDU) For example, AP 1702 (or STA 1704) may be configured to determine that the PPDU comprises an inter-BSS PPDU based on the MAC frame comprising address fields that do not match with a BSSID of a BSS that AP 1702 or STA 1704 belongs to or with a MAC address of AP 1702.

[0151] In an embodiment, after switching to the NPCA PCH, AP 1702 (or STA 1704) may be configured to transmit a first frame indicating the OBSS NAV duration (or TXOP duration) obtained based on the MAC frame of the PPDU. In an embodiment, AP 1702 (or STA 1704) may be configured to receive from STA 1704 (AP 1702) a second frame, in response to the first frame, indicating whether an OBSS NAV duration (or TXOP duration), obtained by STA 1704 (AP 1702), based on the MAC frame of the PPDU, is equal or different than the OBSS NAV duration (or TXOP duration) indicated in the first frame. In an embodiment, the first frame may comprise an initial control frame (ICF), a request-to-send (RTS) frame, a multi-user (MU)-RTS frame, a CTS frame, a BSRP trigger frame, a BAR frame, a trigger frame, a control frame, a quality of service (QoS) null frame, a management frame, or an action frame. In an embodiment, the second frame may comprise an initial control response frame (ICR), a clear-to-send (RTS) frame, a modified CTS frame, a BSR frame, a BA frame, a trigger frame, a control frame, a quality of service (QoS) null frame, a management frame, or an action frame.

[0152] In an embodiment, AP 1702 (or STA 1704) may be configured, based on the OBSS NAV duration (or TXOP duration) obtained by AP 1702 (STA 1704) being equal to the OBSS NAV duration (or TXOP duration) obtained by STA 1704 (AP 1702), to operate (park / camp) on the NPCA PCH during (or within) the OBSS NAV duration (or TXOP duration) indicated by AP 1702 (or STA 1704). In an embodiment, AP 1702 (or STA 1704) may be further configured, based on the OBSS NAV duration (or TXOP duration) obtained by AP 1702 (STA 1704) being equal to the OBSS NAV duration (or TXOP duration) obtained by STA 1704 (AP 1702), to switch (return) from the NPCA PCH to the PCH before an end of (or within) the OBSS NAV duration (or TXOP duration) obtained by AP 1702 (or STA 1704). Conversely, AP 1702 (or STA 1704) may be configured, based on the OBSS NAV duration (or TXOP duration) obtained by AP 1702 (STA 1704) beingDocket No.: 24-3042PCT not equal to the OBSS NAV duration (or TXOP duration) obtained by STA 1704 (AP 1702), to operate (park / camp) on the NPCA PCH during (or within) a length (or duration) of the PPDU. In an embodiment, AP 1702 (or STA 1704) may be further configured, based on the OBSS NAV duration (or TXOP duration) obtained by AP 1702 (STA 1704) being not equal to the OBSS NAV duration (or TXOP duration) obtained by STA 1704 (AP 1702), to switch (return) from the NPCA PCH to the PCH before an end of the PPDU (within the length / duration of the PPDU).

[0153] Returning to FIG. 17, example 1700 begins with a PPDU 1706 being transmitted on the PCH. PPDU 1706 may be transmitted by a STA that does not belong to the BSS of APs 1702 and STA 1704. PPDU 1706 may comprise a MAC frame comprising a MAC header, a frame body, and an FCS field. PPDU 1706 is therefore an inter-BSS (or OBSS) PPDU for APs 1702 and STA 1704. As AP 1702 and STA 1704 operate on the PCH, AP 1702 and / or STA 1704 may (in parallel) detect / sense the transmission of PPDU 1706 and begin to decode (read, detect, process, parse, or receive) PPDU 1706. In an example, AP 1702 and / or STA 1704 may decode (read, detect, process, parse, or receive) a PHY identifier field of PPDU 1706, which allows AP 1702 and STA 1704 to determine a PPDU type of PPDU 1706.

[0154] Next, in an embodiment, AP 1702 and / or STA 1704 may decode (read, detect, process, parse, or receive) a preamble / PHY header of PPDU 1706 to determine if PPDU 1706 is an inter-BSS PPDU. As described above, AP 1702 and / or STA 1704 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 1706 is an inter-BSS PPDU. In example 1700, AP 1702 and / or STA 1704 may determine that PPDU 1706 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 1702

[0155] In another embodiment, alternatively or additionally, AP 1702 and / or STA 1704 may decode (read, detect, process, parse, or receive) the MAC frame (or MPDU) (or a portion of the MAC header of the MAC frame) of PPDU 1706 to determine if PPDU 1706 is an inter-BSS PPDU. The MAC frame may correspond to a first occurring MPDU of PPDU 1706 or may be a single MPDU of PPDU 1706. In an embodiment, AP 1702 and / or STA 1704 may be configured to decode (read, detect, process, parse, or receive) the MAC frame of PPDU 1706 to determine if PPDU 1706 is an inter-BSS PPDU based on failing to determine whether PPDU 1706 is an inter-BSS PPDU based on reading / decoding the preamble / PHY header of PPDU 1706. As described above, AP 1702 and / or STA 1704 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 MAC frame to determine whether the BSSID field indicates a MAC address different than a MAC address of AP 1702.

[0156] Continuing with example 1700, after determining that PPDU 1706 is an inter-BSS PPDU (and, optionally, after failing to obtain an OBSS NAV duration from a preamble or a PHY header of PPDU 1706), AP 1702 and / or STA 1704 may decode (process, parse, or read) a portion of the MAC frame contained inDocket No.: 24-3042PCTPPDU 1706 to determine an OBSS NAV duration (or TXOP duration). In example 1700, the decoded portion of the MAC frame includes one or more fields of the MAC header of the MAC frame. In an embodiment, the one or more fields include all fields of the MAC header. In another embodiment, the one or more fields include one or more of: a frame control (FC) field, a duration field, and one or more address fields of the MAC header. In an embodiment, AP 1702 and / or STA 1704 does not decode the frame body of the MAC frame. In an embodiment, AP 1702 and / or STA 1704 does not decode the FCS field of the MAC frame. In an embodiment, AP 1702 and / or STA 1704 may not decode one or more fields (e.g., Address 3, Sequence Control, Address 4, QoS Control, or HT Control) of a MAC header of the MAC frame. As such, AP 1702 and / or STA 1704 may not be able to determine whether the decoded portion of the MAC frame was decoded correctly (and whether the determined OBSS NAV duration is correct).

[0157] After determining the OBSS NAV duration (or TXOP duration) based on the MAC header of the MAC frame contained in PPDU 1706, AP 1702 and / or STA 1704 may switch from the PCH to the NPCA PCH In an embodiment, AP 1702 and STA 1704 may be configured to switch to the NPCA PCH at the same switching time. In example 1700, AP 1702 and STA 1704 switch from the PCH to the NPCA PCH after decoding the MAC header of the MAC frame contained in PPDU 1706. The switching time may correspond to the time that AP 1702 and STA 1704 finish decoding / reading the MAC header. However, other switching times may also be configured or negotiated / agreed between AP 1702 and STA 1704. In example 1700, AP 1702 and STA 1704 do not decode (process, parse, or read) a frame body or an FCS field of the MAC frame.

[0158] Subsequently, AP 1702 may access the NPCA PCH and transmit a frame 1708 to STA 1704. In an embodiment, frame 1708 indicates a first duration corresponding to the OBSS NAV duration (or TXOP duration) obtained / determined by AP 1702 based on the MAC frame (or a portion of the MAC header of the MAC frame) contained in PPDU 1706. In example 1700, AP 1702 determines the OBSS NAV duration (or TXOP duration) as being equal to “X” (where X represents a time duration, e.g., in microseconds) and thus indicates the value “X” for the first duration in frame 1708. As shown in FIG. 17, frame 1708 may be transmitted via a bandwidth that comprises the NPCA PCH. For example, frame 1708 may be transmitted via the NPCH PCH and SCH2. Frame 1708 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.

[0159] STA 1704 may respond to frame 1708 from AP 1702 by transmitting a frame 1710 to AP 1702. In an embodiment, frame 1710 indicates whether a second duration corresponding to the OBSS NAV duration (or TXOP duration) obtained / determined by STA 1704 based on the MAC frame (or a portion of the MAC header of the MAC frame) contained in PPDU 1706 is equal to the first duration indicated in frame 1708. In example 1700, STA 1704 may determine the OBSS NAV duration (or TXOP duration) as being equal to “Y” (where YDocket No.: 24-3042PCT represents a time duration, e.g., in microseconds) and thus different than the value “X” indicated in frame 1708. As such, STA 1704 may set an indicator in frame 1710 to a first value (e.g., 1) corresponding to the second duration being not equal to the first duration. As shown in FIG. 17, frame 1710 may be transmitted via a bandwidth that comprises the NPCA PCH. For example, frame 1710 may be transmitted via the NPCH PCH and SCH2. Frame 1710 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.

[0160] In an embodiment, based on receiving frame 1708 from AP 1702 indicating the value "X” for the first duration, STA 1704 determines that AP 1702 computed / determined a different value than STA 1704 for the OBSS NAV duration. In an embodiment, based on this determination, STA 1704 may determine that the second duration (corresponding to the OBSS NAV duration (TXOP duration) that STA 1704 obtained based on the MAC frame of PPDU 1706) may be incorrect (or that STA 1704 incorrectly decoded the decoded portion of the MAC frame of PPDU 1706). STA 1704 may thus determine to operate on the NPCA PCH for the duration of PPDU 1706 (STA 1704 may return to the PCH before an end of PPDU 1706). Similarly, based on receiving frame 1710 from STA 1704 indicating that the second duration is different than the first duration, AP 1702 determines that STA 1704 computed / determined a different value than AP 1702 for the OBSS NAV duration. In an embodiment, based on this determination, AP 1702 may determine that the first duration (corresponding to the OBSS NAV duration (TXOP duration) that AP 1702 obtained based on the MAC frame of PPDU 1706) may be incorrect (or that AP 1702 incorrectly decoded the decoded portion of the MAC frame of PPDU 1706). AP 1702 may thus determine (like STA 1704) to operate on the NPCA PCH for the duration of PPDU 1706 (AP 1702 may return to the PCH before an end of PPDU 1706).

[0161] In another example (not shown in FIG. 17), the operation performed by AP 1702, described above, may be performed by STA 1704, and vice versa. That is, frame 1708 may be transmitted by STA 1704 (instead of AP 1702) and frame 1710 may be transmitted by AP 1702 (instead of STA 1704).

[0162] In accordance with the above described operation, in example 1700, AP 1702 and STA 1704 may exchange one or more frames while operating, for duration of PPDU 1706, on the NPCA PCH. For example, AP 1702 may transmit a frame 1712 to STA 1704. Frame 1712 may comprise a data frame, a management frame, or an action frame, for example. STA 1704 may respond to frame 1712 by transmitting a frame 1714 to AP 1702. Frame 1714 may comprise an immediate response frame, such as an Ack frame or a BA frame. AP 1702 and STA 1704 may finish communicating on the NPCA PCH and return to the PCH before an end of PPDU 1706. As such, communication between AP 1702 and STA 1704 may occur on the NPCA PCH, albeit for a shorter time period, allowing some of the buffered traffic between AP 1702 and STA 1704 to be transmitted with minimal delay and avoiding NPCA PCH resources from being wasted during the transmission time of PPDU 1706.Docket No.: 24-3042PCT

[0163] In another example (not shown in FIG. 17), STA 1704 may determine the OBSS NAV duration (or TXOP duration) as being equal to “X” and thus equal to the value “X’’ indicated in frame 1708. As such, STA 1704 may set an indicator in frame 1710 to a first value (e.g , 0) corresponding to the second duration being equal to the first duration. Based on receiving frame 1708 from AP 1702 indicating the value "X” for the first duration, STA 1704 determines that AP 1702 computed / determined the same value as STA 1704 for the OBSS NAV duration. In an embodiment, based on this determination, STA 1704 may determine that the second duration (corresponding to the OBSS NAV duration (TXOP duration) that STA 1704 obtained based on the MAC frame of PPDU 1706) is correct (or that STA 1704 correctly decoded the decoded portion of the MAC frame of PPDU 1706). STA 1704 may thus determine to operate on the NPCA PCH for the OBSS NAV duration that STA 1704 obtained based on the MAC frame (STA 1704 may return to the PCH before an end of the OBSS NAV duration). Similarly, based on receiving frame 1710 from STA 1704 indicating that the second duration is equal to the first duration, AP 1702 determines that STA 1704 computed / determined the same value as AP 1702 for the OBSS NAV duration. In an embodiment, based on this determination, AP 1702 may determine that the first duration (corresponding to the OBSS NAV duration (TXOP duration) that AP 1702 obtained based on the MAC frame of PPDU 1706) is correct (or that AP 1702 correctly decoded the decoded portion of the MAC frame of PPDU 1706). AP 1702 may thus determine to operate on the NPCA PCH for the OBSS NAV duration that AP 1702 obtained based on the MAC frame (AP 1702 may return to the PCH before an end of the OBSS NAV duration). Accordingly, in an example, AP 1702 and STA 1704 may exchange one or more frames while operating, for the OBSS NAV duration, on the NPCA PCH. As such, communication between AP 1702 and STA 1704 may occur on the NPCA PCH for a prolonged period of time. This allows for buffered traffic between AP 1702 and STA 1704 to be transmitted with minimal delay and avoids NPCA PCH resources from being wasted.

[0164] FIG. 18 shows an example 1800 that illustrates an example frame exchange according to an embodiment. Example 1800 is provided for the purpose of illustration only and is not limiting of embodiments. Example 1800 also includes an AP 1802 and a STA 1804. AP 1802 may be an embodiment of AP 1502 or AP 1702, for example. STA 1804 may be an embodiment of STA 1504 or STA 1704, for example. As such, AP 1802 may be configured as described above with respect to AP 1502 or AP 1702, and STA 1804 may be configured as described above with respect to STA 1504 or STA 1704. Additionally, AP 1802 and STA 1804 may be configured to perform the frame exchange illustrated in FIG. 18, which may performed prior to AP 1802 and STA 1804 receiving an inter-BSS PPDU on the PCH. For example, the example frame exchange illustrated in FIG. 18 may be performed in example 1500 before AP 1502 and STA 1504 receive / detect PPDU 1506, in example 1600 before AP 1502 and STA 1504 receive / detect PPDU 1602, or in example 1700 before AP 1702 and STA 1704 receive / detect PPDU 1706.

[0165] As shown in FIG. 18, the example frame exchange may include AP 1802 transmitting a frame 1806 on the PCH. In an embodiment, frame 1806 may indicate support, by AP 1802, of a frame header-basedDocket No.: 24-3042PCTNPCA switching operation. The frame header-based NPCA switching operation corresponds to the NPCA switching operation (described above) and that is based on decoding a portion of a MAC header of a MAC frame of a received inter-BSS PPDU. In an embodiment, frame 1806 may further indicate enablement / disablement (or (activation / deactivation) or (using / not using)), by AP 1802, of the frame headerbased 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.

[0166] The example frame exchange may further include, before or after the transmission of frame 1806, STA 1804 transmitting a frame 1808 to AP 1802. In an embodiment, frame 1808 may indicate support, by STA 1804, of the frame header-based NPCA switching operation. In an embodiment, frame 1808 may further indicate enablement / disablement (or (activation / deactivation) or (using / not using)), by STA 1804, of the frame header-based NPCA switching operation. In an embodiment, where frame 1808 indicates enablement, by STA 1804, of the frame header-based NPCA switching operation, frame 1808 may further comprise a request to AP 1802 to enable the frame header-based NPCA switching operation by AP 1802. In embodiments, frame 1808 may comprise an individually addressed probe request frame, a broadcast 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.

[0167] The example frame exchange may further include, before or after the transmission of frame 1806, AP 1802 transmitting a frame 1810 to STA 1804. In an embodiment, frame 1810 may indicate support, by AP 1802, of the frame header-based NPCA switching operation. In an embodiment, frame 1810 may further indicate enablement / disablement (or (activation / deactivation) or (using / not using)), by AP 1802, of the frame header-based NPCA switching operation. Frame 1810 may be in response to frame 1808. In an embodiment, where frame 1808 comprises a request to AP 1802 to enable the frame header-based NPCA switching operation by AP 1802, frame 1810 may indicate acceptance / rejection of the request. In embodiments, frame 1810 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.

[0168] FIG. 19 illustrates an example process 1900 according to an embodiment. Example process 1900 is provided for the purpose of illustration only and is not limiting of embodiments. Example process 1900 may be performed by an AP such as AP 1502, AP 1702, or AP 1802. As shown in FIG. 19, example process 1900 may include steps 1902, 1904, and 1906. Step 1906 may be optional.

[0169] Step 1902 includes receiving, by the AP and via a PCH, a PPDU. The PPDU may comprise a non- HT PPDU, an HT PPDU, a VHT PPDU, an HE PPDU, an EHT PPDU, or a UHR PPDU.Docket No.: 24-3042PCT

[0170] Step 1904 includes, after obtaining a first duration from a MAC frame of the PPDU and determining, based on the MAC frame, that the PPDU comprises an inter-BSS PPDU, switching, by the AP, from the PCH to an NPCA PCH.

[0171] Step 1906 includes communicating, by the AP, with a STA based on the first duration and a second duration obtained by the STA from the MAC frame. The STA may be associated with the AP.

[0172] In an embodiment, the obtaining of the first duration from the MAC frame comprises obtaining the first duration from a duration field of a MAC header of the MAC frame. In an embodiment, the first duration comprises a first NAV duration or a first TXOP duration. In an embodiment, the second duration comprises a second NAV duration or a second TXOP duration.

[0173] In an embodiment, the determining, based on the MAC frame, that the PPDU comprises the inter- BSS PPDU comprises determining that the PPDU comprises the inter-BSS PPDU based on one or more address fields of a MAC header of the MAC frame. The one or more address fields may comprise at least one of: an "Address 1” field, an “Address 2” field, an “Address 3” field, and an “Address 4” field of the MAC header.

[0174] In an embodiment, 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 MAC frame. In an embodiment, the switching from the PCH to the NPCA PCH further comprises switching from the PCH to the NPCA PCH without computing an FCS field for the MAC frame.

[0175] In an embodiment, the switching from the PCH to the NPCA PCH comprises switching from the PCH to the NPCA PCH after processing a portion of the MAC frame. In an embodiment, the portion comprises all fields of a MAC header of the MAC frame. In an embodiment, the portion comprises one or more fields of the MAC header of the MAC frame. The one or more fields may comprise at least one of: a frame control (FC) field, a duration field, and one or more address fields. In an embodiment, the switching from the PCH to the NPCA PCH comprises switching from the PCH to the NPCA PCH without processing (detecting / reading / parsing / decoding / receiving) a remaining portion, after the portion, of the MAC frame. In an embodiment, the remaining portion comprises at least one of a frame body and an FCS field of the MAC frame.

[0176] In an embodiment, process 1900 further comprises transmitting, by the AP to the STA, a first frame indicating the first duration. In an embodiment, process 1900 further comprises receiving, by the AP from the STA, a second frame indicating the second duration. In an embodiment, the transmitting of the first frame is in response to the receiving of the second frame. In another embodiment, the receiving of the second frame is in response to the transmitting of the first frame. In another embodiment, process 1900 further comprises receiving, by the AP from the STA, a second frame indicating whether the second duration is equal to the first duration. In an embodiment, the receiving of the second frame is in response to the transmitting of the first frame.Docket No.: 24-3042PCT

[0177] In another embodiment, process 1900 further comprises transmitting, by the AP to the STA, a first frame comprising a first indication of whether the first duration is equal to the second duration. In an embodiment, process 1900 further comprises receiving, by the AP from the STA, a second frame indicating the second duration. In an embodiment, the transmitting of the first frame is in response to the receiving of the second frame.

[0178] In an embodiment, the first frame comprises an initial control frame (ICF), a request-to-send (RTS) frame, a multi-user (MU)-RTS frame, a trigger frame, a control frame, a quality of service (QoS) null frame, a management frame, or an action frame. In an embodiment, the second frame comprises an initial control response frame (ICR), a clear-to-send (RTS) frame, a modified CTS frame, a trigger frame, a control frame, a quality of service (QoS) null frame, a management frame, or an action frame.

[0179] In an embodiment, the switching from the PCH to the NPCA PCH comprises operating (camping / parking) on the NPCA PCH. In an embodiment, process 1900 may further comprise, based on the first duration being equal to the second duration, operating ( / camping / parking), by the AP, on the NPCA PCH during the first duration. In an embodiment, process 1900 may further comprise, based on the first duration being equal to the second duration, switching, by the AP, from the NPCA PCH to the PCH before an end of the first duration. In an embodiment, process 1900 may further comprise, based on the first duration not being equal to the second duration, operating ( / camping / parking), by the AP, on the NPCA PCH during a length (duration) of the PPDU. In an embodiment, process 1900 may further comprise, based on the first duration not being equal to the second duration, switching, by the AP, from the NPCA PCH to the PCH before an end of the PPDU.

[0180] In an embodiment, the communicating with the STA in step 1906 comprises transmitting a frame to the STA or receiving a frame from the STA on the NPCA PCH.

[0181] In an embodiment, process 1900 may further comprise transmitting, by the AP, a third frame indicating: support, by the AP, of a frame header-based NPCA switching operation; and / or enablement / disablement, by the AP, of the frame size-based NPCA switching operation. The third 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.

[0182] In an embodiment, process 1900 may further comprise receiving, by the AP from the STA, a fourth frame indicating: support, by the STA, of a frame header-based NPCA switching operation; and / or enablement / disablement, by the STA, of the frame header-based NPCA switching operation. The fourth 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.Docket No.: 24-3042PCT

[0183] In an embodiment, process 1900 may further comprise, in response to the fourth frame, transmitting, by the AP to the STA, a fifth frame indicating: support, by the AP, of a frame header-based NPCA switching operation; and / or enablement / disablement, by the AP, of the frame header-based NPCA switching operation. The fifth 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.

[0184] In an embodiment, process 1900 may further comprise determining, by the AP, that the PPDU comprises a non-HT PPDU and performing step 1904 based on the PPDU comprising a non-HT PPDU.

[0185] FIG. 20 illustrates another example process 2000 according to an embodiment. Example process 2000 is provided for the purpose of illustration only and is not limiting of embodiments. Example process 2000 may be performed by a STA such as STA 1504, STA 1704, or STA 1804. As shown in FIG. 20, example process 2000 may include steps 2002, 2004, and 2006. Step 2006 may be optional.

[0186] Step 2002 includes receiving, by the STA and via a PCH, a PPDU. The PPDU may comprise a non- HT PPDU, an HT PPDU, a VHT PPDU, an HE PPDU, an EHT PPDU, or a UHR PPDU.

[0187] Step 2004 includes, after obtaining a first duration from a MAC frame of the PPDU and determining, based on the MAC frame, that the PPDU comprises an inter-BSS PPDU, switching, by the STA, from the PCH to an NPCA PCH.

[0188] Step 2006 includes communicating, by the STA, with an AP based on the first duration and a second duration obtained by the AP from the MAC frame. The STA may be associated with the AP.

[0189] In an embodiment, the obtaining of the first duration from the MAC frame comprises obtaining the first duration from a duration field of a MAC header of the MAC frame In an embodiment, the first duration comprises a first NAV duration or a first TXOP duration. In an embodiment, the second duration comprises a second NAV duration or a second TXOP duration.

[0190] In an embodiment, the determining, based on the MAC frame, that the PPDU comprises the inter- BSS PPDU comprises determining that the PPDU comprises the inter-BSS PPDU based on one or more address fields of a MAC header of the MAC frame. The one or more address fields may comprise at least one of: an “Address 1” field, an “Address 2” field, an “Address 3” field, and an “Address 4” field of the MAC header.

[0191] In an embodiment, 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 MAC frame. In an embodiment, the switching from the PCH to the NPCA PCH further comprises switching from the PCH to the NPCA PCH without computing an FCS field for the MAC frame.

[0192] In an embodiment, the switching from the PCH to the NPCA PCH comprises switching from the PCH to the NPCA PCH after processing a portion of the MAC frame. In an embodiment, the portion comprises all fields of a MAC header of the MAC frame. In an embodiment, the portion comprises one or more fields of theDocket No.: 24-3042PCTMAC header of the MAC frame. The one or more fields may comprise at least one of: a frame control (FC) field, a duration field, and one or more address fields. In an embodiment, the switching from the PCH to the NPCA PCH comprises switching from the PCH to the NPCA PCH without processing (detecting / reading / parsing / decoding / receiving) a remaining portion, after the portion, of the MAC frame. In an embodiment, the remaining portion comprises at least one of a frame body and an FCS field of the MAC frame.

[0193] In an embodiment, process 2000 further comprises receiving, by the STA from the AP, a first frame indicating the second duration. In an embodiment, process 2000 further comprises transmitting, by the STA to the AP, a second frame indicating the first duration. In an embodiment, the transmitting of the second frame is in response to the receiving of the first frame. In another embodiment, the receiving of the first frame is in response to the transmitting of the second frame. In another embodiment, process 2000 further comprises transmitting, by the STA to the AP, a second frame indicating whether the second duration is equal to the first duration. In an embodiment, the transmitting of the second frame is in response to the receiving of the first frame.

[0194] In another embodiment, process 2000 further comprises receiving, by the STA from the AP, a first frame comprising a first indication of whether the first duration is equal to the second duration. In an embodiment, process 2000 further comprises transmitting, by the STA to the AP, a second frame indicating the first duration. In an embodiment, the receiving of the first frame is in response to the transmitting of the second frame.

[0195] In an embodiment, the first frame comprises an initial control frame (ICF), a request-to-send (RTS) frame, a multi-user (MU)-RTS frame, a trigger frame, a control frame, a quality of service (QoS) null frame, a management frame, or an action frame. In an embodiment, the second frame comprises an initial control response frame (ICR), a clear-to-send (RTS) frame, a modified CTS frame, a trigger frame, a control frame, a quality of service (QoS) null frame, a management frame, or an action frame.

[0196] In an embodiment, the switching from the PCH to the NPCA PCH comprises operating (camping / parking) on the NPCA PCH. In an embodiment, process 2000 may further comprise, based on the first duration being equal to the second duration, operating ( / camping / parking), by the STA, on the NPCA PCH during the first duration. In an embodiment, process 2000 may further comprise, based on the first duration being equal to the second duration, switching, by the STA, from the NPCA PCH to the PCH before an end of the first duration. In an embodiment, process 2000 may further comprise, based on the first duration not being equal to the second duration, operating ( / camping / parking), by the STA, on the NPCA PCH during a length (duration) of the PPDU. In an embodiment, process 2000 may further comprise, based on the first duration not being equal to the second duration, switching, by the STA, from the NPCA PCH to the PCH before an end of the PPDU.Docket No.: 24-3042PCT

[0197] In an embodiment, the communicating with the AP in step 2006 comprises transmitting a frame to the AP or receiving a frame from the AP on the NPCA PCH.

[0198] In an embodiment, process 2000 may further comprise receiving, from the AP, a third frame indicating: support, by the AP, of a frame header-based NPCA switching operation; and / or enablement / disablement, by the AP, of the frame size-based NPCA switching operation. The third 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.

[0199] In an embodiment, process 2000 may further comprise transmitting, by the STA to the AP, a fourth frame indicating: support, by the STA, of a frame header-based NPCA switching operation; and / or enablement / disablement, by the STA, of the frame header-based NPCA switching operation. The fourth 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.

[0200] In an embodiment, process 2000 may further comprise, in response to the fourth frame, receiving, by the STA from the AP, a fifth frame indicating : support, by the AP, of a frame header-based NPCA switching operation; and / or enablement / disablement, by the AP, of the frame header-based NPCA switching operation. The fifth 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.

[0201] In an embodiment, process 2000 may further comprise determining, by the STA, that the PPDU comprises a non-HT PPDU and performing step 2004 based on the PPDU comprising a non-HT PPDU.

[0202] In an embodiment, a STA / AP described in any of the embodiments above may further perform one or more of the NPCA operations described herein below. As would be understood by a person of skill in the art based on the teachings, any of the NPCA operations described below may be combined with the procedures / operations described above.

[0203] Hereinafter, a STA that supports NPCA operation is called an NPCA STA. An AP that supports NPCA operation is called an NPCA AP. A non-AP NPCA STA may set an NPCA Supported field of a UHR MAC Capabilities Information field of a UHR Capabilities element to 1 . In an implementation, a non-AP NPCA STA does not enable the NPCA mode unless the non-AP NPCA STA is associated with an NPCA AP that has enabled NPCA operation.

[0204] In an implementation, an NPCA AP that has an operating bandwidth less than 80 MHz does not enable NPCA operation. In an implementation, an AP of a multiple BSSID set that enables NPCA operation may indicate the same NPCA primary channel, same NPCA minimum duration, same NPCA switching delay, and same NPCA switch back delay as all of the other APs of the same multiple BSSID set that have enabledDocket No.: 24-3042PCTNPCA operation. In an implementation, an AP of a co-hosted BSS that enables NPCA operation may indicate the same NPCA primary channel, same NPCA minimum duration, same NPCA switching delay, and same NPCA switch back delay as all of the other APs of the same co-hosted BSSs that have enabled NPCA operation.

[0205] In an implementation, an NPCA AP that has enabled NPCA operation may set to 1 the NPCA Enabled field in the UHR Operation element of the (Re)Association Response, UHR Link Reconfiguration Notify, Beacon and Probe Response frames that it transmits.

[0206] In an implementation, an NPCA AP with a value (e.g., dotH HEPSROption Implemented) set to true may set the TXVECTOR parameter SPATIAL_REUSE to PSR_DISALLOW for PPDUs that it transmits, and may set the PSR Disallowed subfield in the SR Control field of the Spatial Reuse Parameter Set element to 1 in Management frames it transmits before enabling NPCA operation in its BSS and while NPCA operation remains enabled

[0207] In an implementation, an AP may enable a PHY Header-based (PHYLEN) NPCA operation by setting a MAC Header-based (MOPLEN) NPCA field to 0 and may enable both PHYLEN NPCA and MOPLEN NPCA operation by setting the MOPLEN NPCA field to 1 .

[0208] In an implementation, an NPCA AP may advertise an NPCA Disabled Subchannel Bitmap field in the NPCA Operation Parameters field. The NPCA Disabled Subchannel Bitmap field may indicate the subchannels that are punctured when an NPCA STA operates on the NPCA primary channel:If an NPCA Disabled Subchannel Bitmap field is present, then the NPCA Disabled Subchannel Bitmap Field Present bit may be set to 1 , otherwise the NPCA Disabled Subchannel Bitmap Field Present field may be set to 0.The NPCA Disabled Subchannel Bitmap field value may satisfy the following requirements:• The puncturing pattern indicated by the value of the NPCA Disabled Subchannel Bitmap field is a valid non-OFDMA puncturing pattern.• A 20 MHz subchannel indicated as punctured in the Disabled Subchannel Bitmap field of an EHT Operation element (if any) is also indicated as punctured in the NPCA Disabled Subchannel Bitmap field.An NPCA AP may indicate one or more 20 MHz subchannels as punctured in the NPCA Disabled Subchannel Bitmap field of the EHT Operation Element for the purpose of maximizing the BW of the NPCA operating channel.An NPCA AP may indicate one or more 20 MHz subchannels as punctured in the NPCA Disabled Subchannel Bitmap field of the EHT Operation Element for the purpose of creating a gap between the PPDU that initiated the NPCA switch and the NPCA operating channel.Docket No.: 24-3042PCTIf no NPCA Disabled Subchannel Bitmap field is present in the NPCA Operation Parameters field transmitted by the AP that the STA is associated with, then the subchannels may be punctured during NPCA operation.

[0209] In an implementation, an NPCA AP may indicate a value in the NPCA Primary Channel field, of transmitted NPCA Operation Parameters fields, that corresponds to a channel that is located within the secondary 40 MHz of the BSS operating channel if the BSS is an 80 MHz BSS, that corresponds to a channel that is located within the secondary 80 MHz of the BSS operating channel if the BSS is a 160 MHz BSS, and that corresponds to a channel that is located within the secondary 160 MHz of the BSS operating channel if the BSS is a 320 MHz BSS.

[0210] In an implementation, a non-AP NPCA STA may indicate an NPCA switching delay and an NPCA switch back delay, respectively, in the NPCA Switching Delay field and NPCA Switch Back Delay fields of the OMP Request frames.

[0211] In an implementation, when a non-AP STA that supports NPCA mode (re)associates with an AP, the NPCA mode may be disabled by default for the non-AP STA. In the UHR OMP request sent to enable or update the parameters of NPCA mode for the non-AP STA, a non-AP STA may include the following in the Mode Parameters field of the Mode Tuple field:NPCA switching delay,NPCA switch back delay.

[0212] In an implementation, for a non-AP STA to enable NPCA mode, the associated AP must support NPCA and must have NPCA enabled for the BSS.

[0213] In an implementation, if an NPCA AP that has enabled NPCA operation advertises MU EDCA parameters in the Beacon frames that it transmits, a MU EDCA protocol may apply jointly on both BSS primary channel and NPCA primary channel for a non-AP NPCA STA. In an implementation, an NPCA STA may maintain a single MU EDCA timer that is shared across the BSS primary channel and the NPCA primary channel, transition from using EDCA parameters to using MU EDCA parameters (and vice-versa) at the same time on both the BSS primary channel and the NPCA primary channel based on certain conditions that occur on either the BSS primary channel or the NPCA primary channel, and when the STA is operating on the NPCA primary channel, use the same MU EDCA parameters as are used on the BSS primary channel except that AIFSN[AC] may be set to 0 for all ACs. When the STA switches back to the BSS primary channel, it may revert to using the AIFSN[AC] values from the dot11 MUEDCATable.

[0214] In an implementation, an NPCA STA does not switch to the NPCA primary channel for NPCA operation if NPCA mode has not been enabled by its associated AP.

[0215] In an implementation, an NPCA STA may switch to the NPCA primary channel for NPCA operation if the NPCA mode has been enabled for the BSS of which it is a member and either condition 1) or 2) is met:Docket No.: 24-3042PCT1) the STA received a PPDU and / or received a PHY-RXSTART. indication primitive for an HE / EHT / UHR PPDU on the BSS primary channel and all of the following conditions are true: a) Condition 2) is not true. b) The PPDU is classified by the STA as in inter-BSS PPDU. c) At least one of the following conditions is true:1) The value of the MAC variable NPCA_PPDU_REM_DUR derived from the received PPDU is greater than the value indicated in the most recently received or transmitted NPCA Minimum Duration Threshold field corresponding to the BSS of which the STA is a member. ii) If the NPCA AP corresponding to the BSS of which the STA is a member has enabled MOPLEN NPCA in addition to PHYLEN NPCA and the value of the MAC variable NPCA_PHY_TXOP_REM_DUR derived from the received PPDU is greater than the value indicated in the most recently received or transmitted NPCA Minimum Duration Threshold field corresponding to the BSS of which the STA is a member. d) The bandwidth of the PPDU is determined by the STA to be 20, 40, 80 or 160 MHz, based on the Bandwidth field in the PHY preamble of the PPDU and the channel occupied by the PPDU does not overlap with the NPCA primary channel. e) If the STA maintains an intra-BSS NAV, it is zero.2) All of the following conditions are true: a) A sequence of three PPDUs, separated by aSIFSTime, is identified on the BSS primary channel, comprising an initial Control frame, an initial response frame, and a third PPDU following the initial response frame. b) The STA received at least the first PPDU containing the initial Control frame and the PHY- RXSTART. indication and / or the PHY-RXEARLYSIG. indication of the third PPDU. c) An indication that a valid TXOP was obtained on the BSS primary channel, as verified by the receipt of a PHY-RXEARLYSIG. indication or PHYRXSTART. indication primitive corresponding to the third PPDU that occurs during a time window that: i) begins at aSIFSTime + ICR_Timeout after the MAC receives a PHY-RXEND. indication primitive corresponding to the first PPDU, where ICR_Timeout is equal to:(1) The length (in usee) of the expected CTS if the initial Control frame is an RTS or an MU-RTS Trigger frame,(2) the value of RXTIME calculated using Equation (27-147) with the value of LENGTH replaced by the value from the UL Length field of the Common Info field, if the initial Control frame is a BSRP Trigger frame or a BSRP NTB Trigger frame.Docket No.: 24-3042PCT ii) has a duration that is equal to NPCA_START_TIMEOUT which is aSIFSTime + (2 x aSlotTime) + aRxPHYStartDelay. d) At least one of the three PPDUs in the sequence of PPDUs is classified by the STA as an inter-BSS PPDU. e) At least one of the following conditions is true: i) The NPCA AP corresponding to the BSS of which the STA is a member has enabled PHYLEN NPCA only and the value of the MAC variable NPCA_PPDU_REM_DUR derived from the received third PPDU of the sequence of PPDUs is greater than the value indicated in the most recently received or transmitted NPCA Minimum Duration Threshold field corresponding to its BSS. ii) If the NPCA AP corresponding to the BSS of which the STA is a member has enabled MOPLEN NPCA in addition to PHYLEN NPCA and the value of the MAC variable NPCA_CFRAME_TXOP_REM_DUR derived from the received first PPDU (containing the initial Control frame of the control frame exchange) of the sequence of PPDUs is greater than the value indicated in the most recently received or transmitted NPCA Minimum Duration Threshold field corresponding to its associated BSS. f) The bandwidth of the third PPDU is determined by the STA to be 20, 40, 80, 160 or 320 MHz based on the Bandwidth field in the PHY preamble of the PPDU not overlap with the NPCA primary channel and the channel occupied by the PPDU does not overlap with the NPCA primary channel. g) If the STA maintains an intra-BSS NAV, it is zero at the time of the receipt of the PHYRXSTART.indication and / or the PHY-RXEARLYSIG.indication of the first PPDU.

[0216] In an implementation, when a PHY-CCA.indication(BUSY) primitive corresponding to the start of the reception of a PPDU is indicated at an NPCA STA while operating on the BSS primary channel, the values of the MAC variables NPCA_PPDU_REM_DUR, NPCA_PHY_TXOP_REM_DUR and NPCA_TIMER are all set to 0. When a PHY-CCA.indication(BUSY) corresponding to the start of the reception of a PPDU containing an initial Control frame is indicated at an NPCA STA while operating on the BSS primary channel, the MAC variable NPCA_CFRAME_TXOP_REM_DUR is set to 0.

[0217] In an implementation, the MAC variable NPCA_PPDU_REM_DUR derived from a received PPDU is equal to the value in usee, of the remaining duration of the received PPDU, determined by the MAC at the time of the receipt of the PHY-RXSTART. indication primitive associated with the received PPDU, by subtracting the time elapsed between the reception of the PHY-CCA.indication(BUSY) and PHYRXSTART.indication primitives associated with the received PPDU from the value of RXTIME of the received PPDU.

[0218] In an implementation, the MAC variable NPCA_PHY_TXOP_REM_DUR derived from a received PPDU is:Docket No.: 24-3042PCTSet to 0, if the RXVECTOR parameter TXOP_DURATION is UNSPECIFIED, or if the NPCA AP corresponding to the BSS of which the STA is a member has not enabled MOPLEN NPCA.Otherwise, it is equal to the value in usee, of the remaining duration of the PPDU, determined by the MAC at the time of the receipt of the PHY-RXSTART. indication primitive associated with the received PPDU, by subtracting the time elapsed between the reception of the PHY-CCA.indication(BUSY) and PHY- RXSTART. indication primitives associated with the received PPDU from the value of RXTIME corresponding to the received PPDU, plus the value of the TXOP_DURATION parameter of the RXVECTOR of the PPDU.

[0219] In an implementation, the MAC variable NPCA_CFRAME_TXOP_REM_DUR derived from a received PPDU is:Set to 0, if the NPCA AP corresponding to the BSS of which the STA is a member has not enabled MOPLEN NPCA.Otherwise, it is set to the value in the Duration / ID field of the initial Control frame in the received PPDU at the receipt of the PHY-RXEND. indication primitive of the PPDU that contained the frame. The value of NPCA_CFRAME_TXOP_REM_DUR is reduced by the amount of time elapsed between the PHY- RXEND.indication primitive of the initial Control frame from which the value of NPCA_CFRAME_TXOP_REM_DUR was determined and the PHY-RXSTART. indication primitive of the third PPDU of the frame exchange sequence identified in condition 2) above at the time of the receipt of the PHY- RXSTART. indication primitive of the third PPDU.

[0220] In an implementation, when an NPCA STA switches to the NPCA primary channel for NPCA operation, then the following rules apply:1) If the STA switches from the BSS primary channel to the NPCA primary channel based on meeting condition 1) described above, the STA initiates the switch at the NPCA HE switch time and shall be ready to transmit and receive frames (subject to its capabilities and operating mode) on the NPCA primary channel no later than the value of its most recently indicated NPCA switching delay after the NPCA HE switch time. The NPCA HE switch time is the point in time immediately after the reception of the HE-SIG-A / U-SIG field of the received PPDU from condition 1) above.2) If the STA switches from the BSS primary channel to the NPCA primary channel based on meeting condition 2) described above, the STA initiates the switch at the NPCA NHT switch time and shall be ready to transmit and receive frames addressed to it (subject to its capabilities and operating mode) on the NPCA primary channel no later than the value of its most recently indicated NPCA switching delay after the NPCA NHT switch time. The NPCA NHT switch time is equal to the point in time that is 3 x TSYM after the reception of the L-SIG field of the third PPDU of the received sequence of PPDUs from condition 2) above.3) The STA uses the same EDCA parameter set and EPCS EDCA parameter set values for operation on the NPCA primary channel as it uses on the BSS primary channel.Docket No.: 24-3042PCT4) At each NPCA HE switch time or NPCA NHT switch time, as appropriate, if the STA is an AP or if the STA is a non-AP STA and transmission of frames that are not a response to a Trigger frame is not disabled by the MU EDCA protocol, the STA may initiate a TXOP on the NPCA primary channel with the following exceptions: a) Each time that the STA switches to the NPCA primary channel, the STA does:I) If condition 1) is met, set NPCA_CFRAME_TXOP_REM_DUR to O, set NPCA_TIMER to the largest non-zero value of the variables NPCA_PPDU_REM_DUR, NPCA_PHY_TXOP_REM_DUR and NPCA_CFRAME_TXOP_REM_DUR, minus the switch back delay that the STA indicated in the most recently transmitted NPCA Operation Parameters field.II) Store the existing values of the variables QSRC[AC], CW[AC] and the backoff counter for each EDCAF. ill) Set QSRC[AC] for each AC to the value of the Initial NPCA QSRC field of the NPCA Operation Parameters received from its associated NPCA AP. iv) initialize variables CW[AC] to 2I"'‘-QSRC_NPCAX(CWmin[AC] + 1 ) - 1 . v) invoke the backoff procedure even if the medium for the NPCA primary channel is not busy. vi) initiate countdown of the MAC variable NPCA_TIMER in units of 1 usee.5) A first STA does not initiate a transmission on the NPCA primary channel to a second STA until theNPCA switching delay time of the second STA has elapsed since the NPCA HE switch time at the first STA if the first STA is switching due to condition 1 ) above or since the NPCA NHT switch time at the first STA if the first STA is switching due to condition 2) above6) The STA begins all frame exchanges on the NPCA primary channel with an initial control frame (ICF) using non-HT PPDU or non-HT duplicate PPDU format using a rate of 6 Mb / s, 12 Mb / s, or 24 Mb / s. a) For TXOPs initiated by an AP, the ICF is a BSRP Trigger frame or an MU-RTS Trigger frame except when at least one of the target non-AP STA(s) is operating in the DUO mode, in which case, the ICF may be a BSRP Trigger frame or a BSRP NTB Trigger frame but not an MU-RTS. In addition, the ICF conforms to the rules for Dynamic Unavailability Operation (DUO) mode if at least one of the target non-AP STA(s) is operating in DUO mode, to the rules for Enhanced multi-link single-radio (EMLSR) operation if at least one of the target non-AP STA(s) is affiliated with a non-AP MLD that is operating in EMLSR mode, and to the rules for Dynamic power save (DPS) operation if at least one of the target non-AP STA(s) is operating in DPS mode. b) For TXOPs initiated by a non-AP STA, the initial control frame is a BSRP NTB Trigger frame, except that if the non-AP STA is operating in the Dynamic Unavailability Operation mode (DUO), then the ICF conforms to the DUO mode rules.Docket No.: 24-3042PCT7) An NPCA AP that transmits a Trigger frame on the NPCA primary channel indicates RU index values that use the NPCA primary channel as the reference primary channel.8) An NPCA STA that transmits a Trigger frame on the NPCA primary channel sets the NPCA Primary Indication field to 1 in the Special User Info field, otherwise, this field is set to 0.9) The 20 MHz channels occupied by PPDUs transmitted by the STA shall meet all of the following conditions: a) include at least the NPCA primary channel. b) all be within the BSS bandwidth. c) not include any of the channels occupied by either the PPDU mentioned in condition 1) or by the third PPDU mentioned in condition 2), whichever caused the STA to switch from the BSS primary channel to the NPCA primary channel. d) not include channels that are indicated as punctured in the Disabled Subchannel Bitmap field in the EHT Operation element or in the NPCA Disabled Subchannel Bitmap field in the UHR Operation element.10) UHR ELR PPDUs, HE ER SU PPDUs, EHT MCS14 / 15 shall not be transmitted on the NPCA primary channel.11) Dynamic Subband Operation shall not be used on the NPCA primary channel.12) If TBTT for the BSS occurs while an NPCA AP is operating on the NPCA primary channel, the scheduling of the transmission of the Beacon frame and following group addressed frames shall be deferred until immediately after the AP switches back to the BSS primary channel.

[0221] In an example, an AP and associated STAs are not required to switch back to the BSS primary channel at TBTT. The group addressed frames may be buffered and delivered immediately following the next DTIM Beacon, unless explicitly specified otherwise. Further, in an example, exponential backoff may apply on the NPCA primary channel when there are failed transmissions.

[0222] In an implementation, an NPCA STA shall switch back to the BSS primary channel when the NPCA_TIMER expires. In an implementation, when the STA switches back to the BSS primary channel, it may:1) replace the current values of the variables QSRC[AC], CW[AC] and the backoff counter for each EDCAF with the values that it stored when it switched to the NPCA primary channel.2) resume the backoff procedure.

Claims

Docket No.: 24-3042PCTCLAIMSWhat is claimed is:

1. A method comprising: detecting, by an access point (AP) and via a primary channel (PCH), a non-high throughput (non- HT) physical layer protocol data unit (PPDU); obtaining, by the AP, a first network allocation vector (NAV) duration from a medium access protocol (MAC) frame of the non-HT PPDU; after determining that the non-HT PPDU comprises an inter-basic service set (inter-BSS) PPDU, switching, by the AP, from the PCH to a non-primary channel access (NPCA) PCH; transmitting, by the AP to a station (STA) and via the NPCA PCH, a first frame indicating the first NAV duration; receiving, by the AP from the STA, a second frame indicating a second NAV duration, obtained by the STA for the MAC frame of the non-HT PPDU; and based on the first NAV duration being equal to the second NAV duration, communicating, by the AP and during the first NAV duration, with the STA on the NPCA PCH.

2. A method comprising: receiving, by an access point (AP) and via a primary channel (PCH), a physical layer protocol data unit (PPDU); after obtaining a first duration from a medium access control (MAC) frame of the PPDU and determining, based on the MAC frame, that the PPDU comprises an inter-basic service set (inter-BSS) PPDU, switching, by the AP, from the PCH to a non-primary channel access (NPCA) PCH; and communicating, by the AP, with a station (STA) based on the first duration and a second duration obtained by the STA from the MAC frame.

3. The method of claim 2, 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 MAC frame.

4. The method of any of claims 2-3, wherein the switching from the PCH to the NPCA PCH comprises switching from the PCH to the NPCA PCH without computing a frame check sequence (FCS) field for the MAC frame.

5. The method of any of claims 2-4, wherein the switching from the PCH to the NPCA PCH comprises switching from the PCH to the NPCA PCH after processing a portion of the MAC frame.

6. The method of claim 5, wherein the portion comprises all fields of a MAC header of the MAC frame.

7. The method of claim 5, wherein the portion comprises one or more fields of a MAC header of the MAC frame.Docket No.: 24-3042PCT8. The method of claim 7, wherein the one or more fields comprise at least one of a frame control (FC) field, a duration field, and one or more address fields.

9. The method of any of claims 5-8, wherein the switching from the PCH to the NPCA PCH comprises switching from the PCH to the NPCA PCH without processing a remaining portion, after the portion, of the MAC frame.

10. The method of claim 9, wherein the remaining portion comprises at least one of a frame body and a frame check sequence (FCS) field of the MAC frame.

11. The method of any of claims 2-10, wherein the obtaining of the first duration from the MAC frame comprises obtaining the first duration from a duration field of a MAC header of the MAC frame.

12. The method of any of claims 2-11 , wherein the first duration comprises a first network allocation vector (NAV) duration.

13. The method of any of claims 2-12, wherein the first duration comprises a first transmission opportunity (TXOP) duration.

14. The method of any of claims 2-13, wherein the determining, based on the MAC frame, that the PPDU comprises the inter-BSS PPDU comprises determining that the PPDU comprises the inter-BSS PPDU based on one or more address fields of a MAC header of the MAC frame.

15. The method of claim 14, wherein the one or more address fields comprise at least one of: an "Address 1” field, an “Address 2” field, an “Address 3” field, and an “Address 4” field of the MAC header.

16. The method of any of claims 2-15, further comprising transmitting, by the AP to the STA, a first frame indicating the first duration.

17. The method of claim 16, further comprising receiving, bytheAP from the STA, a second frame indicating the second duration.

18. The method of claim 17, wherein the transmitting of the first frame is in response to the receiving of the second frame.

19. The method of claim 16, further comprising receiving, bytheAP from the STA, a second frame indicating whether the second duration is equal to the first duration.

20. The method of claim 17, wherein the receiving of the second frame is in response to the transmitting of the first frame.21 . The method of any of claims 2-15, further comprising transmitting, by the AP to the STA, a first frame comprising a first indication of whether the first duration is equal to the second duration.

22. The method of claim 21 , further comprising receiving, bytheAP from the STA, a second frame indicating the second duration.

23. The method of claim 22, wherein the transmitting of the first frame is in response to the receiving of the second frame.Docket No.: 24-3042PCT24. The method of any of claims 16-23, wherein the first frame comprises an initial control frame (ICF), a request-to-send (RTS) frame, a multi-user (MU)-RTS frame, a trigger frame, a control frame, a quality of service (QoS) null frame, a management frame, or an action frame25. The method of any of claims 17-20, 22, and 23, wherein the second frame comprises an initial control response frame (ICR), a clear-to-send (RTS) frame, a modified CTS frame, a trigger frame, a control frame, a quality of service (QoS) null frame, a management frame, or an action frame.

26. The method of any of claims 2-25, wherein the second duration comprises a second network allocation vector (NAV) duration.

27. The method of any of claims 2-25, wherein the second duration comprises a second transmission opportunity (TXOP) duration.

28. The method of any of claims 2-27, wherein the switching from the PCH to the NPCA PCH comprises operating on the NPCA PCH.

29. The method of any of claims 2-28, further comprising, based on the first duration being equal to the second duration, operating, by the AP, on the NPCA PCH during the first duration.

30. The method of any of claims 2-29, further comprising, based on the first duration being equal to the second duration, switching, by the AP, from the NPCA PCH to the PCH before an end of the first duration.31 . The method of any of claims 2-28, further comprising, based on the first duration not being equal to the second duration, operating, by the AP, on the NPCA PCH during a length of the PPDU.

32. The method of any of claims 2-28 or 30, further comprising, based on the first duration not being equal to the second duration, switching, by the AP, from the NPCA PCH to the PCH before an end of the PPDU.

33. The method of any of claims 2-32, wherein the communicating with the STA comprises transmitting a frame to the STA or receiving a frame from the STA on the NPCA PCH.

34. The method of any of claims 2-33, further comprising transmitting, by the AP, a third frame indicating: support, by the AP, of a frame header-based NPCA switching operation; and / or enablement / disablement, by the AP, of the frame header-based NPCA switching operation.

35. The method of claim 34, wherein the third 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.

36. The method of any of claims 2-35, further comprising: receiving, by the AP from the STA, a fourth frame indicating: support, by the STA, of a frame header-based NPCA switching operation; and / or enablement / disablement, by the STA, of the frame header-based NPCA switching operation; and in response to the fourth frame, transmitting, by the AP to the STA, a fifth frame indicating:Docket No.: 24-3042PCT support, by the AP, of a frame header-based NPCA switching operation; and / or enablement / disablement, by the AP, of the Frame header-based NPCA switching operation.

37. The method of claim 36, wherein the fourth 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.

38. The method of claim 36, wherein the fifth 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.

39. The method of any of claims 2-38, further comprising determining, by the AP, that the PPDU comprises a non-high throughput (non-HT) PPDU.

40. The method of claim 39, wherein the switching, by the AP, from the PCH to the NPCA PCH is further based on the PDDU comprising the non-HT PPDU.

41. The method of claim 2, wherein the PPDU comprises a high throughput (HT) PPDU, a very high throughput (VHT) PPDU, a high efficiency (HE) PPDU, an extremely high throughput (EHT) PPDU, or an ultra-high reliability (UHR) PPDU.

42. A method comprising: detecting, by a station (STA) and via a primary channel (PCH), a non-high throughput (non-HT) physical layer protocol data unit (PPDU); obtaining, by the STA, a first network allocation vector (NAV) duration from a medium access protocol (MAC) frame of the non-HT PPDU; after determining that the non-HT PPDU comprises an inter-basic service set (inter-BSS) PPDU, switching, by the STA, from the PCH to a non-primary channel access (NPCA) PCH; receiving, by the STA from an access point (AP) and via the NPCA PCH, a first frame indicating a second NAV duration, obtained by the AP from the MAC frame of the non-HT PPDU; transmitting, by the STA to the AP, a second frame indicating the first NAV duration; and based on the first NAV duration being equal to the second NAV duration, communicating, by the STA and during the first NAV duration, with the AP on the NPCA PCH.

43. A method comprising: receiving, by a station (STA) and via a primary channel (PCH), a physical layer protocol data unit (PPDU); and after obtaining a first duration from a medium access control (MAC) frame of the PPDU and determining, based on the MAC frame, that the PPDU comprises an inter-basic service set (inter-BSS) PPDU, 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) based on the first duration and a second duration obtained by the AP from the MAC frame.Docket No.: 24-3042PCT44. The method of claim 43, 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 MAC frame.

45. The method of any of claims 43-44, wherein the switching from the PCH to the NPCA PCH comprises switching from the PCH to the NPCA PCH without computing a frame check sequence (FCS) field for the MAC frame.

46. The method of any of claims 43-45, wherein the switching from the PCH to the NPCA PCH comprises switching from the PCH to the NPCA PCH after processing a portion of the MAC frame.

47. The method of claim 46, wherein the portion comprises all fields of a MAC header of the MAC frame.

48. The method of claim 47, wherein the portion comprises one or more fields of a MAC header of the MAC frame.

49. The method of claim 48, wherein the one or more fields comprise at least one of a frame control (FC) field, a duration field, and one or more address fields.

50. The method of any of claims 46-49, wherein the switching from the PCH to the NPCA PCH comprises switching from the PCH to the NPCA PCH without processing a remaining portion, after the portion, of the MAC frame.51 . The method of claim 50, wherein the remaining portion comprises at least one of a frame body and a frame check sequence (FCS) field of the MAC frame.

52. The method of any of claims 43-51 , wherein the obtaining of the first duration from the MAC frame comprises obtaining the first duration from a duration field of a MAC header of the MAC frame.

53. The method of any of claims 43-52, wherein the first duration comprises a first network allocation vector (NAV) duration.

54. The method of any of claims 43-53, wherein the first duration comprises a first transmission opportunity (TXOP) duration.

55. The method of any of claims 43-54, wherein the determining, based on the MAC frame, that the PPDU comprises the inter-BSS PPDU comprises determining that the PPDU comprises the inter-BSS PPDU based on one or more address fields of a MAC header of the MAC frame.

56. The method of claim 55, wherein the one or more address fields comprise at least one of: an “Address 1” field, an “Address 2” field, an “Address 3” field, and an “Address 4” field of the MAC header.

57. The method of any of claims 43-56, further comprising receiving, by the STA from the AP, a first frame indicating the second duration.

58. The method of claim 57, further comprising transmitting, by the STA to the AP, a second frame indicating the first duration.

59. The method of claim 58, wherein the receiving of the first frame is in response to the transmitting of the second frame.Docket No.: 24-3042PCT60. The method of claim 57, further comprising transmitting, by the STA to the AP, a second frame indicating whether the second duration is equal to the first duration.61 . The method of claim 60, wherein the transmitting of the second frame is in response to the receiving of the first frame.

62. The method of any of claims 43-56, further comprising receiving, by the STA from the AP, a first frame comprising a first indication of whether the first duration is equal to the second duration.

63. The method of claim 63, further comprising transmitting, by the STA to the AP, a second frame comprising the first duration.

64. The method of claim 63, wherein the receiving of the first frame is in response to the transmitting of the second frame.

65. The method of any of claims 57-64, wherein the first frame comprises an initial control frame (IGF), a request-to-send (RTS) frame, a multi-user (MU)-RTS frame, a trigger frame, a control frame, a quality of service (QoS) null frame, a management frame, or an action frame.

66. The method of any of claims 58-61 , 63, and 64, wherein the second frame comprises an initial control response frame (ICR), a clear-to-send (RTS) frame, a modified CTS frame, a trigger frame, a control frame, a quality of service (QoS) null frame, a management frame, or an action frame.

67. The method of any of claims 43-66, wherein the second duration comprises a second network allocation vector (NAV) duration.

68. The method of any of claims 43-66, wherein the second duration comprises a second transmission opportunity (TXOP) duration.

69. The method of any of claims 43-68, wherein the switching from the PCH to the NPCA PCH comprises operating on the NPCA PCH.

70. The method of any of claims 43-69, further comprising, based on the first duration being equal to the second duration, operating, by the STA, on the NPCA PCH during the first duration.71 . The method of any of claims 43-70, further comprising, based on the first duration being equal to the second duration, switching, by the STA, from the NPCA PCH to the PCH before an end of the first duration.

72. The method of any of claims 43-69, further comprising, based on the first duration not being equal to the second duration, operating, by the STA, on the NPCA PCH during a length of the PPDU.

73. The method of any of claims 43-69 or 71 , further comprising, based on the first duration not being equal to the second duration, switching, by the STA, from the NPCA PCH to the PCH before an end of the PPDU.

74. The method of any of claims 43-73, wherein the communicating with the AP comprises transmitting a frame to the AP or receiving a frame from the AP on the NPCA PCH.Docket No.: 24-3042PCT75. The method of any of claims 43-74, further comprising receiving, by the STA from the AP, a third frame indicating: support, by the AP, of a frame header-based NPCA switching operation; and / or enablement / disablement, by the AP, of the frame header-based NPCA switching operation.

76. The method of claim 75, wherein the third 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.

77. The method of any of claims 43-76, further comprising: transmitting, by the STA to the AP, a fourth frame indicating: support, by the STA, of a frame header-based NPCA switching operation; and / or enablement / disablement, by the STA, of the frame header-based NPCA switching operation; and in response to the fourth frame, receiving, by the STA from the AP, a fifth frame indicating: support, by the AP, of a frame header-based NPCA switching operation; and / or enablement / disablement, by the AP, of the frame header-based NPCA switching operation.

78. The method of claim 77, wherein the fourth 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.

79. The method of claim 77, wherein the fifth 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.

80. The method of any of claims 43-79, further comprising detecting, by the AP, that the PPDU comprises a non-high throughput (non-HT) PPDU.81 . The method of claim 80, wherein the switching, by the AP, from the PCH to the NPCA PCH is further based on the PDDU comprising the non-HT PPDU.

82. The method of claim 43, wherein the PPDU comprises a high throughput (HT) PPDU, a very high throughput (VHT) PPDU, a high efficiency (HE) PPDU, an extremely high throughput (EHT) PPDU, or an ultra-high reliability (UHR) PPDU.

83. 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 1-82.

84. 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- 82.

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