Non-primary channel access (NPCA) switching operation

Abstract

An access point (AP) determines that a physical layer (PHY) protocol data unit (PPDU) being received via a first channel comprises an inter-basic service set (inter-BSS) PPDU. The AP switches from the first channel to a second channel based on determining that the PPDU being received via the first channel comprises an inter-BSS PPDU. The AP determines whether a first duration, required to transmit data of a first category, buffered at the AP, on the second channel, exceeds a value based on a second duration indicated in the PPDU. The AP switches from the second channel to the first channel at a first time, where the first time is based on whether the first duration exceeds the value based on the second duration.

Description

Docket No.: 24-3062PCTTITLENON-PRIMARY CHANNEL ACCESS (NPCA) SWITCHING OPERATION CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application No. 63 / 735,357, filed December 18, 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 is an example that illustrates non-primary channel access (NPCA) operation.

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

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

[0014] FIG. 12 illustrates an example that highlights a problem that may arise in existing NPCA operation.

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

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

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

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

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

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

[0021] FIG. 19 illustrates another example process according to an embodiment.Docket No.: 24-3062PCTDETAILED DESCRIPTION

[0022] In the present disclosure, various embodiments are presented as examples of how the disclosed techniques may be implemented and / or how the disclosed techniques may be practiced in environments and scenarios. It will be apparent to persons skilled in the relevant art that various changes in form and detail can be made therein without departing from the scope. After reading the description, it will be apparent to one skilled in the relevant art how to implement alternative embodiments. The present embodiments may not be limited by any of the described exemplary embodiments. The embodiments of the present disclosure will be described with reference to the accompanying drawings. Limitations, features, and / or elements from the disclosed example embodiments may be combined to create further embodiments within the scope of the disclosure. Any figures which highlight the functionality and advantages are presented for example purposes only. The disclosed architecture is sufficiently flexible and configurable, such that it may be utilized in ways other than those shown. For example, the actions listed in any flowchart may be re-ordered or only optionally used in some embodiments.

[0023] Embodiments may be configured to operate as needed. The disclosed mechanism may be performed when certain criteria are met, for example, in a station, an access point, a radio environment, a network, a combination of the above, and / or the like. Example criteria may be based, at least in part, on for example, wireless device or network node configurations, traffic load, initial system set up, packet sizes, traffic characteristics, a combination of the above, and / or the like. When the one or more criteria are met, various example embodiments may be applied. Therefore, it may be possible to implement example embodiments that selectively implement disclosed protocols.

[0024] In this disclosure, "a” and "an” and similar phrases are to be interpreted as "at least one” and "one or more.” Similarly, any term that ends with the suffix “(s)” is to be interpreted as "at least one” and “one or more.” In this disclosure, the term “may” is to be interpreted as “may, for example.” In other words, the term “may” is indicative that the phrase following the term “may” is an example of one of a multitude of suitable possibilities that may, or may not, be employed by one or more of the various embodiments. The terms “comprises” and “consists of’, as used herein, enumerate one or more components of the element being described. The term “comprises” is interchangeable with “includes” and does not exclude unenumerated components from being included in the element being described. By contrast, “consists of’ provides a complete enumeration of the one or more components of the element being described. The term “based on”, as used herein, may be interpreted as “based at least in part on” rather than, for example, “based solely on”. The term “and / or” as used herein represents any possible combination of enumerated elements. For example, “A, B, and / or C” may represent A; B; C; A and B; A and C; B and C; or A, B, and C.

[0025] If A and B are sets and every element of A is an element of B, A is called a subset of B. In this specification, only non-empty sets and subsets are considered. For example, possible subsets of B = {STA1 , STA2] are: {STA1}, {STA2}, and {STA1 , STA2}. The phrase “based on” (or equally “based at least on”) isDocket No.: 24-3062PCT indicative that the phrase following the term “based on” is an example of one of a multitude of suitable possibilities that may, or may not, be employed to one or more of the various embodiments. The phrase “in response to” (or equally “in response at least to”) is indicative that the phrase following the phrase “in response to” is an example of one of a multitude of suitable possibilities that may, or may not, be employed to one or more of the various embodiments. The phrase “depending on” (or equally “depending at least to”) is indicative that the phrase following the phrase “depending on" is an example of one of a multitude of suitable possibilities that may, or may not, be employed to one or more of the various embodiments. The phrase “employing / using” (or equally “employing / using at least”) is indicative that the phrase following the phrase “employing / using” is an example of one of a multitude of suitable possibilities that may, or may not, be employed to one or more of the various embodiments.

[0026] The term configured may relate to the capacity of a device whether the device is in an operational or non-operational state. Configured may refer to specific settings in a device that effect the operational characteristics of the device whether the device is in an operational or non-operational state. In other words, the hardware, software, firmware, registers, memory values, and / or the like may be “configured" within a device, whether the device is in an operational or nonoperational state, to provide the device with specific characteristics. Terms such as “a control message to cause in a device” may mean that a control message has parameters that may be used to configure specific characteristics or may be used to implement certain actions in the device, whether the device is in an operational or non-operational state.

[0027] In this disclosure, parameters (or equally called, fields, or Information elements: lEs) may comprise one or more information objects, and an information object may comprise one or more other objects. For example, if parameter (IE) N comprises parameter (IE) M, and parameter (IE) M comprises parameter (IE) K, and parameter (IE) K comprises parameter (information element) J. Then, for example, N comprises K, and N comprises J. In an example embodiment, when one or more messages / frames comprise a plurality of parameters, it implies that a parameter in the plurality of parameters is in at least one of the one or more messages / frames but does not have to be in each of the one or more messages / frames.

[0028] Many features presented are described as being optional through the use of “may” or the use of parentheses. For the sake of brevity and legibility, the present disclosure does not explicitly recite each and every permutation that may be obtained by choosing from the set of optional features. The present disclosure is to be interpreted as explicitly disclosing all such permutations. For example, a system described as having three optional features may be embodied in seven ways, namely with just one of the three possible features, with any two of the three possible features or with three of the three possible features.

[0029] Many of the elements described in the disclosed embodiments may be implemented as modules. A module is defined here as an element that performs a defined function and has a defined interface to other elements. The modules described in this disclosure may be implemented in hardware, software in combination with hardware, firmware, wetware (e.g., hardware with a biological element) or a combinationDocket No.: 24-3062PCT thereof, which may be behaviorally equivalent. For example, modules may be implemented as a software routine written in a computer language configured to be executed by a hardware machine (such as C, C++, Fortran, Java, Basic, Matlab or the like) or a modeling / simulation program such as Simulink, Stateflow, GNU Octave, or LabVIEWMathScript. It may be possible to implement modules using physical hardware that incorporates discrete or programmable analog, digital and / or quantum hardware. Examples of programmable hardware comprise: computers, microcontrollers, microprocessors, application-specific integrated circuits (ASICs); field programmable gate arrays (FPGAs); and complex programmable logic devices (CPLDs). Computers, microcontrollers, and microprocessors are programmed using languages such as assembly, C, C++, or the like. FPGAs, ASICs and CPLDs are often programmed using hardware description languages (HDL) such as VHSIC hardware description language (VHDL) or Verilog that configure connections between internal hardware modules with lesser functionality on a programmable device. The mentioned technologies are often used in combination to achieve the result of a functional module.

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

[0031] As shown in FIG. 1 , the example wireless communication networks may include an Institute of Electrical and Electronic Engineers (IEEE) 802.11 (WLAN) infra-structure network 102. WLAN infra-structure network 102 may include one or more basic service sets (BSSs) 110 and 120 and a distribution system (DS) 130.

[0032] BSS 110-1 and 110-2 each includes a set of an access point (AP or AP STA) and at least one station (STA or non-AP STA). For example, BSS 110-1 includes an AP 104-1 and a STA 106-1 , and BSS 1 10-2 includes an AP 104-2 and STAs 106-2 and 106-3. The AP and the at least one STA in a BSS perform an association procedure to communicate with each other.

[0033] DS 130 may be configured to connect BSS 110-1 and BSS 110-2. As such, DS 130 may enable an extended service set (ESS) 150. Within ESS 150, APs 104-1 and 104-2 are connected via DS 130 and may have the same service set identification (SSID).

[0034] WLAN infra-structure network 102 may be coupled to one or more external networks. For example, as shown in FIG. 1 , WLAN infra-structure network 102 may be connected to another network 108 (e.g., 802.X) via a portal 140. Portal 140 may function as a bridge connecting DS 130 of WLAN infra-structure network 102 with the other network 108.

[0035] The example wireless communication networks illustrated in FIG. 1 may further include one or more ad-hoc networks or independent BSSs (IBSSs). An ad-hoc network or IBSS is a network that includes a plurality of STAs that are within communication range of each other. The plurality of STAs are configured so that they may communicate with each other using direct peer-to-peer communication (i.e., not via an AP).

[0036] For example, in FIG. 1 , STAs 106-4, 106-5, and 106-6 may be configured to form a first IBSS 112- 1. Similarly, STAs 106-7 and 106-8 may be configured to form a second IBSS 112-2. Since an IBSS doesDocket No.: 24-3062PCT not include an AP, it does not include a centralized management entity. Rather, STAs within an IBSS are managed in a distributed manner. STAs forming an IBSS may be fixed or mobile.

[0037] A STA as a predetermined functional medium may include a medium access control (MAC) layer that complies with an IEEE 802.11 standard. A physical layer interface for a radio medium may be used among the APs and the non-AP stations (STAs). The STA may also be referred to using various other terms, including mobile terminal, wireless device, wireless transmit / receive unit (WTRU), user equipment (UE), mobile station (MS), mobile subscriber unit, or user. For example, the term "user” may be used to denote a STA participating in uplink Multi-user Multiple Input, Multiple Output (MU MIMO) and / or uplink Orthogonal Frequency Division Multiple Access (OFDMA) transmission.

[0038] A physical layer (PHY) protocol data unit (PPDU) may be a composite structure that includes a PHY preamble and a payload in the form of a PHY service data unit (PSDU). For example, the PSDU may include a PHY preamble and header and / or one or more MAC protocol data units (MPDUs). The information provided in the PHY preamble may be used by a receiving device to decode the subsequent data in the PSDU. In instances in which PPDUs are transmitted over a bonded channel (channel formed through channel bonding), the preamble fields may be duplicated and transmitted in each of the multiple component channels. The PHY preamble may include both a legacy portion (or “legacy preamble”) and a non-legacy portion (or “non-legacy preamble”). The legacy preamble may be used for packet detection, automatic gain control and channel estimation, among other uses. The legacy preamble also may generally be used to maintain compatibility with legacy devices. The format of, coding of, and information provided in the non-legacy portion of the preamble is based on the particular IEEE 802.11 protocol to be used to transmit the payload.

[0039] A frequency band may include one or more sub-bands or frequency channels For example, PPDUs conforming to the IEEE 802.11 n, 802.1 1ac, 802.11 ax and / or 802.11 be standard amendments may be transmitted over the 2.4 GHz, 5 GHz, and / or 6 GHz bands, each of which may be divided into multiple 20 MHz channels. The PPDUs may be transmitted over a physical channel having a minimum bandwidth of 20 MHz. Larger channels may be optionally formed through channel bonding of a primary 20 MHz channel and one or more 20 MHz secondary channels. For example, PPDUs may be transmitted over physical channels having bandwidths of 40 MHz, 80 MHz, 160 MHz, or 320 MHz by bonding together a primary 20 MHz channel and 1 , 3, 7, or 15 secondary channel respectively. The primary channel is a common channel operation for all STAs where management frames are sent by the AP to ensure that all STAs (regardless of channel bonding support) can receive.

[0040] FIG. 2 is a block diagram illustrating example implementations of a STA 210 and an AP 260. As shown in FIG. 2, STA 210 may include at least one processor 220, a memory 230, and at least one transceiver 240. AP 260 may include at least one processor 270, a memory 280, and at least one transceiver 290. Processor 220 / 270 may be operatively connected to memory 230 / 280 and / or to transceiver 240 / 290.Docket No.: 24-3062PCT

[0041] Processor 220 / 270 may implement functions of the PHY layer, the MAC layer, and / or the logical link control (LLC) layer of the corresponding device (STA 210 or AP 260). Processor 220 / 270 may include one or more processors and / or one or more controllers. The one or more processors and / or one or more controllers may comprise, for example, a general-purpose processor, a digital signal processor (DSP), a microcontroller, an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), a logic circuit, or a chipset, for example.

[0042] Memory 230 / 280 may include a read-only memory (ROM), a random-access memory (RAM), a flash memory, a memory card, a storage medium, and / or other storage unit. Memory 230 / 280 may comprise one or more non-transitory computer readable mediums. Memory 230 / 280 may store computer program instructions or code that may be executed by processor 220 / 270 to carry out one or more of the operations / embodiments discussed in the present application. Memory 230 / 280 may be implemented (or positioned) within processor 220 / 270 or external to processor 220 / 270. Memory 230 / 280 may be operatively connected to processor 220 / 270 via various means known in the art.

[0043] Transceiver 240 / 290 may be configured to transmit / receive radio signals. In an embodiment, transceiver 240 / 290 may implement a PHY layer of the corresponding device (STA 210 or AP 260). In an embodiment, STA 210 and / or AP 260 may be a multi-link device (MLD), that is a device capable of operating over multiple links as defined by the IEEE 802.11 standard. As such, STA 210 and / or AP 260 may each implement multiple PHY layers. The multiple PHY layers may be implemented using one or more of transceivers 240 / 290.

[0044] FIG. 3 illustrates an example format of a MAC frame. In operation, a STA may construct a subset of MAC frames for transmission and may decode a subset of received MAC frames upon validation. The particular subsets of frames that a STA may construct and / or decode may be determined by the functions supported by the STA. A STA may validate a received MAC frame using the frame check sequence (FCS) contained in the frame and may interpret certain fields from the MAC headers of all frames.

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

[0046] The MAC header includes a frame control field, an optional duration / ID field, address fields, an optional sequence control field, an optional QoS control field, and an optional HT control field.

[0047] The frame control field includes the following subfields: protocol version, type, subtype, “To DS’’, “From DS”, “More Fragments”, retry, power management, “More Data , protected frame, and +HTC.

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

[0049] The type and subtype subfields together identify the function of the MAC frame. There are three frame types: control, data, and management. Each of the frame types has several defined subtypes. BitsDocket No.: 24-3062PCT within the subtype subfield are used to indicate a specific modification of the basic data frame (subtype 0). For example, in data frames, the most significant bit (MSB) of the subtype subfield, bit 7 (B7) of the frame control field, is defined as the QoS subfield. When the QoS subfield is set to 1 , it indicates a QoS data frame, which is a data frame that contains a QoS control field in its MAC header. The second MSB of the subtype field, bit 6 (B6) of the frame control field, when set to 1 in data subtypes, indicates a data frame that contain no frame body field.

[0050] The “To DS” subfield indicates whether a data frame is destined to the distribution system (DS). The “From DS” subfield indicates whether a data frame originates from the DS.

[0051] The “More Fragments” subfield is set to 1 in all data or management frames that have another fragment to follow the MAC service data unit (MSDU) or MAC management protocol data unit (MMPDU) carried by the MAC frame. The “More Fragments” subfield is set to 0 in all other frames in which the “More Fragments” subfield is present.

[0052] The retry subfield is set to 1 in any data or management frame that is a retransmission of an earlier frame. It is set to 0 in all other frames in which the retry subfield is present. A receiving STA uses this indication to aid it in the process of eliminating duplicate frames. These rules do not apply for frames sent by a STA under a block agreement.

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

[0054] The “More Data” subfield indicates to a STA in power save (PS) mode that bufferable units (BUs) are buffered for that STA at the AP. The “More Data" subfield is valid in individually addressed data or management frames transmitted by an AP to a STA in PS mode. The “More Data” subfield is set to 1 to indicate that at least one additional buffered BU is present for the STA.

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

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

[0057] The duration / ID field of the MAC header indicates various contents depending on the frame type and subtype and the QoS capabilities of the sending STA. For example, in control frames of the power save poll (PS-Poll) subtype, the duration / ID field carries an association identifier (AID) of the STA that transmitted the frame in the 14 least significant bits (LSB), with the 2 most significant bits (MSB) set to 1 . In other frames sent by STAs, the duration / ID field contains a duration value (in microseconds) which is used by a recipient to update a network allocation vector (NAV). The NAV is a counter that indicates to a STA an amount of time during which the STA must defer from accessing the shared medium.

[0058] Up to four address fields may be present in the MAC frame format. The address fields are used to indicate the basic service set identifier (BSSID), source address (SA), destination address (DA), transmitting address (TA), and receiving address (RA). Certain frames may not contain some of the address fields. Certain address field usage may be specified by the relative position of the address field (1-4) within the MAC header,Docket No.: 24-3062PCT independent of the type of address present in that field. Specifically, the address 1 field always identifies the intended receiver(s) of the frame, and the address 2 field, where present, always identifies the transmitter of the frame.

[0059] The sequence control field includes two subfields, a sequence number subfield and a fragment number subfield. The sequence number subfield in data frames indicates the sequence number of the MSDU (if not in an Aggregated MSDU (A-MSDU)) or A-MSDU. The sequence number subfield in management frames indicates the sequence number of the frame. The fragment number subfield indicates the number of each fragment of an MSDU or MMPDU. The fragment number is set to 0 in the first or only fragment of an MSDU or MMPDU and is incremented by one for each successive fragment of that MSDU or MMPDU. The fragment number is set to 0 in a MAC protocol data unit (MPDU) containing an A-MSDU, or in an MPDU containing an MSDU or MMPDU that is not fragmented. The fragment number remains constant in all retransmissions of the fragment

[0060] The QoS control field identifies the traffic category (TC) or traffic stream (TS) to which the MAC frame belongs. The QoS control field may also indicate various other QoS related, A-MSDU related, and mesh- related information about the frame. This information can vary by frame type, frame subtype, and type of transmitting STA. The QoS control field is present in all data frames in which the QoS subfield of the subtype subfield is equal to 1.

[0061] The HT control field is present in QoS data, QoS null, and management frames as determined by the +HTC subfield of the frame control field.

[0062] The frame body field is a variable length field that contains information specific to individual frame types and subtypes. The frame body may include one or more MSDUs or MMPDUs. The minimum length of the frame body is 0 octets.

[0063] The FCS field contains a 32-bit Cyclic Redundancy Check (CRC) code. The FCS field value is calculated over all of the fields of the MAC header and the frame body field.

[0064] FIG. 4 illustrates an example trigger frame 400. Trigger frame 400 may correspond to a basic trigger frame as defined in the existing IEEE 802.1 1 ax standard amendment. Trigger frame 400 may be used by an AP to allocate resources for and solicit one or more TB PPDU transmissions from one or more STAs. Trigger frame 400 may also carry other information required by a responding STA to transmit a TB PPDU to the AP.

[0065] As shown in FIG. 4, trigger frame 400 includes a Frame Control field, a Duration field, a receiver address (RA) field, a transmitter address (TA) field, a Common Info field, a User List Info field, a Padding field, and an FCS field.

[0066] The Frame Control field includes the following subfields: protocol version, type, subtype, To DS, From DS, more fragments, retry, power management, more data, protected frame, and +HTC.

[0067] The Duration field indicates various contents depending on frame type and subtype and the QoS capabilities of the sending STA. For example, in control frames of the power save poll (PS-Poll) subtype, theDocket No.: 24-3062PCTDuration field carries an association identifier (AID) of the STA that transmitted the frame in the 14 least significant bits (LSB), and the 2 most significant bits (MSB) are both set to 1 . In other frames sent by STAs, the Duration field contains a duration value (in microseconds) which is used by a recipient to update a network allocation vector (NAV).

[0068] The RA field is the address of the STA that is intended to receive the incoming transmission from the transmitting station. The TA field is the address of the STA transmitting trigger frame 400 if trigger frame 400 is addressed to STAs that belong to a single BSS. The TA field is the transmitted BSSID if the trigger frame 400 is addressed to STAs from at least two different BSSs of the multiple BSSID set.

[0069] The common info field may have a format as illustrated by common info field 600 described further below. The common info field specifies a trigger frame type of trigger frame 400, a transmit power of trigger frame 400 in dBm, and several key parameters of a TB PPDU that is transmitted by a STA in response to trigger frame 400. The trigger frame type of a trigger frame used by an AP to receive QoS data using UL MU operation is referred to as a basic trigger frame.

[0070] The User List Info field contains a User Info field per STA addressed in trigger frame 400. The per STA User Info field includes, among others, an AID subfield, an RU Allocation subfield, a Spatial Stream (SS) Allocation subfield, an MCS subfield to be used by a STA in a TB PPDU transmitted in response to trigger frame 400, and a Trigger Dependent User Info subfield. The Trigger Dependent User Info subfield can be used by an AP to specify a preferred access category (AC) per STA. The preferred AC sets the minimum priority AC traffic that can be sent by a participating STA. The AP determines the list of participating STAs, along with the BW, MCS, RU allocation, SS allocation, Tx power, preferred AC, and maximum duration of the TB PPDU per participating STA.

[0071] The Padding field is optionally present in trigger frame 400 to extend the frame length to give recipient STAs enough time to prepare a response for transmission one SIPS (short interframe spacing) after the frame is received. The Padding field, if present, is at least two octets in length and is set to all 1 s.

[0072] The FCS field is used by a STA to validate a received frame and to interpret certain fields from the MAC headers of a frame.

[0073] FIG. 5 illustrates an example multi-user request to send (MU-RTS) trigger frame 500. MU-RTS trigger frame 500 may be used by an AP to solicit simultaneous CTS frames from multiple STAs to transmit a downlink (DL) MU PPDU to the multiple STAs. As shown in FIG. 5, MU-RTS trigger frame 500 may comprise a frame control field, a duration field, an RA field, a TA field, a common info field, one or more user info fields, a padding field, and an FCS field. The frame control, TA, RA, padding, and FCS fields may be similar to the corresponding fields of trigger frame 400 described above. The common info field may have a format as illustrated by common info field 600 described further below. The duration field may be set to the time, in microseconds, required to transmit the DL MU PPDU, plus the time required to transmit one CTS frame, one ACK frame (if required), and three SIFS periods.Docket No.: 24-3062PCT

[0074] The one or more user info fields correspond respectively to the one or more STAs solicited by MU- RTS trigger frame 500. As shown in FIG. 5, a user info field may comprise an AID12 subfield, an RU allocation subfield, reserved bits, and a PS 160 subfield. The AID12 subfield comprises an association identifier of the STA to which the user info field is addressed. The RU allocation subfield indicates a channel on which the solicited STA is to transmit the CTS frame. In an example, this may include a primary 20 MHz channel, a primary 40 MHz, a primary 80 MHz channel, a primary 160 MHz, an 80+80 Mhz channel, or a 320 MHz channel.

[0075] FIG. 6 illustrates an example Common Info field 600. Common Info field 600 may be an embodiment of the Common Info field of trigger frame 400 or MU-RTS trigger frame 500, for example. As shown in FIG. 6, Common Info field 600 may include a Trigger Type subfield, a UL Length subfield, a More TF subfield, a CS required subfield, a UL BW subfield, a Gl and HE / EHT-LTF Type / Triggered TXS Mode subfield, a first Reserved subfield, a Number of HE / EHT-LTF Symbols subfield, a second Reserved subfield, an LDPC Extra Symbol Segment subfield, an AP Tx Power subfield, a Pre-FEC Padding Factor subfield, a PE Disambiguity subfield, an UL Spatial Reuse subfield, a third Reserved subfield, an HE / EHT P160 subfield, a Special User Info Field Flag subfield, an EHT Reserved subfield, a fourth Reserved subfield, and a Trigger Dependent Common Info subfield. The Trigger Type subfield, UL Length subfield, More TF subfield, CS required subfield, UL BW subfield, Gl and HE-LTF Type / Triggered TXS Mode subfield, first Reserved subfield, Number of HE / EHT-LTF Symbols subfield, second Reserved subfield, LDPC Extra Symbol Segment subfield, AP Tx Power subfield, Pre-FEC Padding Factor subfield, PE Disambiguity subfield, UL Spatial Reuse subfield, third Reserved subfield, HE / EHT P160 subfield, Special User Info Field Flag subfield, EHT Reserved subfield, fourth Reserved subfield, and Trigger Dependent Common Info subfield may have the same content and interpretation as corresponding subfields of an EHT variant Common Info field defined in the IEEE 802.11 be draft amendment (“IEEE P802.11 be / D3.1 , March 2023”).

[0076] FIG. 7 illustrates an example 700 of a Request-to-Send (RTS) / Clear-to-Send (CTS) procedure. Example 700 may be an example according to the RTS / CTS procedure as defined in section 10.3.2.9 of the IEEE 802.1 1 standard draft “IEEE P802.1 1-REVme™ / D3.0, April 2023.” As shown in FIG. 7, example 700 may include STAs 702 and 704. Other STAs of the same BSS may also be within communication range of STAs 702 and 704.

[0077] In an example, STA 702 may transmit an RTS frame 706 to STA 704. STA 702 may transmit RTS frame 706 to protect from hidden STA(s) the transmission of a data frame 710 that STA 702 intends to transmit. RTS frame 706 may include a Duration / ID field. The Duration / ID field may be set to the time, in microseconds, required to transmit data frame 710, plus one CTS frame, plus one ACK frame (if required), plus three SIFS (Short Interframe Spacing) periods.

[0078] In an example, STA 704 may respond to RTS frame 706 by transmitting a CTS frame 708 to STA 702. CTS frame 708 may be transmitted one SIFS period after RTS frame 706. STA 704 may respond toDocket No.: 24-3062PCTRTS frame 706 when RTS frame 706 is addressed to STA 704 and after considering the NAV, unless the NAV was set by a frame originating from STA 702. STA 704 may respond to the RTS frame 706 when RTS frame 706 is addressed to STA 704 and if the NAV indicates idle. For a non-S1 G STA, the NAV indicates idle when the NAV count is 0 or when the NAV count is non-zero but a nonbandwidth signaling TA obtained from a TA field of RTS frame 706 matches a saved TXOP holder address. For an S1 G STA, the NAV indicates idle when both the NAV and RID (response indication deferral) counters are 0 or when either the NAV or RID counter is non-zero but the TA field of RTS frame 706 matches the saved TXOP holder address.

[0079] STA 704 may set an RA field of CTS frame 708 to a nonbandwidth signaling TA obtained from the TA field of RTS frame 706. STA 704 may set a Duration field of CTS frame 708 based on the Duration / ID field of RTS frame 706, namely as equal to the value of the Duration / ID field of RTS frame 706, adjusted by subtracting the time required to transmit CTS frame 708 and one SIFS period.

[0080] Upon receiving CTS frame 708, STA 702 may wait one SIFS period before transmitting data frame 710. STA 704 may transmit an ACK frame 712 in response to data frame 710. STA 704 may transmit ACK frame 712 one SIFS after receiving data frame 710.

[0081] As shown in example 700, other STAs within communication range of STAs 702 and 704, and belonging to the same BSS, may set their NAVs according to RTS frame 706 and / or CTS frame 708. For example, a STA receiving RTS frame 706 may set its NAV based on the Duration / ID field of RTS frame 706. Another STA receiving CTS frame 708 may set its NAV based on the Duration field of CTS frame 708. As such, the other STAs may not access the channel using EDCA until the end of transmission of ACK frame 712.

[0082] FIG. 8 is an example 800 that illustrates a multi-user Request-to-Send (MU-RTS) / Clear-to-Send (CTS) procedure. Example 800 may be an example according to the MU-RTS / CTS procedure as defined in section 26.2.6 of the IEEE 802.1 1 standard draft. As shown in FIG. 8, example 800 may include an AP 802 and STAs 804 and 806. STAs 804 and 806 may be associated with AP 802. For the purpose of illustration, example 800 also illustrates STAs of an overlapping basic service set (OBSS) relative to the BSS of AP 802 (OBSS STAs). The OBSS STAs, as shown in FIG. 8, may be hidden from AP 802 (outside of the communication range of AP 802) or exposed to AP 802 (within the communication range of AP 802).

[0083] In example 800, AP 802 wishes to transmit a downlink (DL) multi-user (MU) PPDU 814 to STAs 804 and 806. DL MU PPDU 814 may comprise data for each of STAs 804 and 806. DL MU PPDU 814 may occupy a plurality of channels (e.g., 20 MHz channels). Each channel of the plurality of channels may carry the data for a respective STA (e.g., STA 804, STA 806) served by DL MU PPDU 814.

[0084] As shown in FIG. 8, to protect the transmission of DL MU PPDU 814 to STAs 804 and 806 from interference by OBSS STAs hidden from AP 802, AP 802 may use the MU-RTS / CTS procedure to initiate a TXOP and to protect the TXOP frame exchange sequence. AP 802 may initiate the TXOP by transmitting an MU-RTS trigger frame 808 that solicits simultaneous CTS frame transmissions from STAs 804 and 806.Docket No.: 24-3062PCT

[0085] MU-RTS trigger frame 808 may have a format as illustrated by MU-RTS trigger frame 500 illustrated in FIG. 5. As such, MU-RTS trigger frame 808 may comprise a frame control field, a duration field, an RA field, a TA field, a common info field, one or more user info fields, a padding field, and an FCS field The duration field may be set to the time, in microseconds, required to transmit DL MU PPDU 814, plus the time required to transmit one CTS frame, one ACK frame (if required), and three SIFS periods.

[0086] The one or more user info fields correspond respectively to the one or more STAs solicited by the MU-RTS trigger frame. In example 800, MU-RTS trigger frame 808 may comprise a user info field for each of STAs 804 and 806 indicating that a CTS frame is solicited from each of STAs 804 and 806. As shown in FIG. 8, a user info field may comprise an AID12 subfield, an RU allocation subfield, reserved bits, and a PS 160 subfield. The AID12 subfield comprises an association identifier of the STA to which the user info field is addressed. The RU allocation subfield indicates a channel on which the solicited STA is to transmit the CTS frame. In an example, this may include a primary 20 MHz channel, a primary 40 MHz, a primary 80 MHz channel, a primary 160 MHz, an 80+80 Mhz channel, or a 320 MHz channel.

[0087] AP 802 may send MU-RTS trigger frame 808 in a PPDU that occupies one or more channels (e.g ., 20 MHz channels). In an example, for each channel occupied by the PPDU that carries MU-RTS trigger frame 808, AP 802 may request at least one non-AP STA to send a CTS frame that occupies that channel. In an example, AP 802 may not request that a non-AP STA send a CTS frame that occupies a channel that is not occupied by the PPDU carrying MU-RTS trigger frame 808.

[0088] After transmitting MU-RTS trigger frame 808, AP 802 may wait for a CTSTimeout interval of aSIFSTime + aSlotTime + aRxPHYStartDelay that begins when a MAC layer of AP 802 receives a PHYTXEND confirm primitive for transmitted MU-RTS trigger frame 808 If the MAC layer does not receive a PHY-RXEARLYSIG. indication or a PHY-RXSTART. indication primitive during the CTSTimeout interval, AP 802 may conclude that the transmission of MU-RTS trigger frame 808 has failed, and, if MU-RTS trigger frame 808 initiated a TXOP, AP 802 may invoke its backoff procedure. If the MAC layer receives a PHY- RXEARLYSIG. indication or a PHY-RXSTART. indication primitive during the CTSTimeout interval, then the MAC layer may wait for the corresponding PHY-RXEND. indication primitive to determine whether transmission of MU-RTS trigger frame 808 was successful. The receipt of a CTS frame from any non-AP STA addressed by MU-RTS trigger frame 808 before the PHY-RXEND. indication primitive shall be interpreted as the successful transmission of MU-RTS trigger frame 808, permitting the frame exchange sequence to continue. The receipt of any other type of frame shall be interpreted as a failure of the transmission of MU-RTS trigger frame 808. AP 802 may process the received frame and, if MU-RTS trigger frame 808 initiated a TXOP, AP 802 shall invoke its backoff procedure at the PHY-RXEND. indication primitive.

[0089] In example 800, on receiving MU-RTS trigger frame 808, STAs 804 and 806 respond by transmitting respectively CTS frames 810 and 812 to AP 802. In an example, STAs 804 and 806 begin the transmissionDocket No.: 24-3062PCT of CTS frames 810 and 812, respectively, at the SIFS time boundary after an end of a received PPDU comprising MU-RTS trigger frame 808. In an example, STA 804 (or STA 806) responds to MU-RTS trigger frame 808 with a CTS frame when the following conditions are met: MU-RTS trigger frame 808 comprises a user info field addressed to the STA (the AID12 subfield of the user info field is equal to the 12 LSBs of the AID of the STA) and MU-RTS trigger frame 808 is sent by an AP with which the STA is associated; and the UL MU CS condition indicates that the medium is idle as described in section 26.5.2.5 (UL MU CS mechanism) of the IEEE 802.1 1 standard (“IEEE P802.11-REVme™ / D3.0, April 2023”). Otherwise, if one of the conditions is not met, STA 804 (or STA 806) does not send a CTS frame to AP 802.

[0090] In an example, STAs 804 and 806 may set an RA field of respectively CTS frames 810 and 812 to a TA obtained from the TA field of MU-RTS trigger frame 808. In an example, STAs 804 and 806 may set a duration field of respectively CTS frames 810 and 812 based on the duration field of MU-RTS trigger frame 808, namely as equal to the value of the duration field of MU-RTS trigger frame 808, adjusted by subtracting the time required to transmit respectively CTS frames 810 and 812 and one SIFS period.

[0091] OBSS STAs exposed to AP 802 may receive MU-RTS trigger frame 808 due to being within the communication range of AP 802. In an example, as shown in FIG. 8, on receiving MU-RTS trigger frame 808, OBSS STAs exposed to AP 802 set their respective NAVs based on the duration field of MU-RTS trigger frame 808. As such, the OBSS STAs exposed to AP 802 may not access the wireless medium for the duration of the TXOP initiated by AP 802.

[0092] OBSS STAs hidden from AP 802 do not receive MU-RTS trigger frame 808 due to being outside the communication range of AP 802. However, in an example, as shown in FIG. 8, some of the OBSS STAs hidden from AP 802 may receive CTS frame 810 and / or CTS frame 812 and may set their respective NAVs based on the duration field of CTS frame 810 and / or CTS frame 812. As such, some of the OBSS STAs hidden from AP 802 may also not access the wireless medium for the duration of the TXOP initiated by AP 802.

[0093] On receiving CTS frame 810 and / or CTS frame 812, AP 802 may wait one SIFS period before transmitting DL MU PPDU 814. On receiving DL MU PPDU 814, STAs 804 and 806 may respond by transmitting respective BlockAck (BA) frames 816 and 818 to AP 802.

[0094] It is envisioned in future IEEE 802.11 standards that a STA (AP STA or non-AP STA) may access a non-primary channel to communicate with another STA. Such operation may be referred to as non-primary channel access (NPCA) operation. Specifically, in addition to a default primary channel (which is used by all STAs in the BSS and via which the AP transmits management frames), the STA may have one or more secondary channels considered as NPCA primary channels. The STA may transmit or receive on a channel that includes an NPCA primary channel but that does not necessarily include the primary channel (e.g., when the primary channel is unavailable). The STA may maintain a NAV for an NPCA primary channel independent of the NAV associated with the primary channel. FIG. 9 shows an example that illustrates non-primaryDocket No.: 24-3062PCT channel access (NPCA) operation. For the purpose of illustration, NPCA operation is contrasted with single primary channel (non-NPCA STA) operation. As shown in FIG. 9, the STA may be capable of operating over a plurality of channels. According to non-NPCA operation, the plurality of channels may include a primary channel (PCH), a first secondary channel (SCH1 ), a second secondary channel (SCH2), and a third secondary channel (SCH2). According to NPCA operation, the same channels may include a primary channel (PCH), a first secondary channel (SCH1), an NPCA primary channel (NPCA PCH), and a second secondary channel (SCH2). It is noted that the position of the NPCA primary channel may or may not be as shown in the example of FIG. 9. For example, the NPCA primary channel may correspond to SCH1 .

[0095] In an implementation, as shown in FIG. 10, in non-NPCA operation, a virtual carrier sense (CS) function (e.g., NAV) may be associated with only the PCH. Secondary channels may have only a physical CS function (e.g., energy detection) associated with them, which may be performed only when contending for transmission on the PCH. As such, as shown in FIG. 9, the STA may only transmit on a channel that includes the PCH (e.g., PCH, PCH+SCH1 , PCH+SCH1+SCH2, PCH+SCH1 +SCH2+SCH3) and only when the NAV associated with the PCH is zero (and the physical CS function indicates “channel idle” for all channels being used).

[0096] In contrast, as shown in FIG. 10, in NPCA operation, a virtual CS function (e.g., NAV) may be associated with multiple channels (e.g., PCH and NPCA PCH). As such, as shown in FIG. 9, the STA may transmit on channels that do not include the PCH but that include the NPCA PCH (e.g., NPCA PCH, NPCA PCH+SCH1 , NPCA PCH+SCH2) if the NAV associated with the NPCA PCH is zero (and the physical CS indicates “channel idle” for all channels being used). In an implementation, the STA may also transmit on channels that do not include the PCH but that include the NPCA PCH (e.g., NPCA PCH, NPCA PCH+SCH1 , NPCA PCH+SCH2) if the STA detects that the NPCA PCH is idle using physical CS for at least a medium synchronization duration.

[0097] 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”).

[0098] In an implementation, the STA may perform CS in parallel on multiple channels, including the PCH and the NPCA PCH. Such a STA is referred to herein as a concurrent CCA NPCA STA (such a STA may also be referred to as a concurrent CCA multiple primary channel (MPC) STA or a Type 1 STA). Because of its concurrent CCA capability, a concurrent CCA NPCA STA is capable of medium synchronization simultaneously on multiple channels (e.g., PCH and NPCA PCH). Medium synchronization on a channel (e.g., PCH or NPCA PCH) may be performed by detecting a frame that includes NAV information or by listening to the channel for at least a medium synchronization duration and finding the channel idle throughout the medium synchronization duration. An NPCA STA that does not support this capability may perform CSDocket No.: 24-3062PCT 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.

[0099] FIG. 11 shows an example 1 100 that illustrates an NPCA operation. As shown in FIG. 11 , example 1 100 includes an AP and a STA associated with the AP. The AP and the STA may both support NPCA operation and may operate over a plurality of channels, including a primary channel (PCH), an NPCA primary channel (NPCA PCH), a first secondary channel (SCH1), and a second secondary channel (SCH2).

[0100] Example 1100 may begin with the AP transmitting a frame 1 102 on the PCH. Frame 1102 may indicate a medium synchronization duration for the NPCA PCH. The medium synchronization duration of a channel indicates a minimum duration that a STA must listen to the channel before the STA is able to transmit on the channel (if the STA does not receive via the channel before the end of the medium synchronization duration a frame that indicates NAV information). Frame 1 102 may be a management frame, such as a beacon frame, for example.

[0101] Subsequently, while the AP and STA operate on the PCH, transmission of a frame 1104 from an OBSS may begin on the PCH. The AP and the STA may detect frame 1 104 on the PCH. In an implementation, the AP and STA may be configured to set a NAV associated with the PCH based on receiving frame 1 104 on the PCH. Frame 1104 may indicate a transmission (of one or more frames including frame 1104) on the PCH. A duration of the transmission on the PCH may be provided by a duration field of frame 1 104, a transmission opportunity (TXOP) duration field of an inter-BSS PPDU comprising frame 1104, or a length field of the inter-BSS PPDU. The AP and STA may set their NAVs for the PCH based on the duration of the OBSS transmission on the PCH (hereinafter, OBSS NAV duration or OBSS TXOP duration).

[0102] In accordance with NPCA operation, on receiving an inter-BSS PPDU and obtaining the OBSS NAV duration, the AP and the STA may be configured to switch to the NPCA PCH for the OBSS NAV duration. In an example, the AP and the STA may switch to the NPCA PCH at time T1 as shown in example 1100. Here, time T1 may correspond to the time for switching from the PCH to the NPCA PCH after obtaining the OBSS NAV duration. The AP and STA may be configured to finish transmitting on the NPCA PCH before an end of the OBSS NAV duration and to return to the PCH by the end of the OBSS NAV duration, by time T2, as shown in example 1100. Here, time T2 may correspond to the time for switching from the NPCA PCH to the PCH by the end of OBSS NAV duration.

[0103] 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.: 24-3062PCT frame 1 102). In example 1 100, the AP may be a concurrent CCA STA capable of concurrent CS on both the PCH and the NPCA PCH. As such, provided that the NPCA PCH is idle, the AP may access the NPCA PCH, without waiting for expiration of the “MediumSyncDelay” timer, to transmit a frame 1 106 on the NPCA PCH. In an example, the STA may be a non-concurrent CCA STA. On switching to the NPCA PCH, the STA may not be aware of whether a transmission is ongoing on the NPCA PCH. The STA may thus be configured to sense the NPCA PCH until the "MediumSyncDelay” timer expires before attempting to access the NPCA PCH. However, the STA may acquire medium synchronization on the NPCA PCH before expiration of the "MediumSyncDelay” timer if the STA receives a frame indicating NAV information on the NPCA PCH. For example, the STA may acquire medium synchronization on the NPCA PCH on receiving frame 1106 from the AP. The STA may reset the “MediumSyncDelay” timer to zero and may then proceed to access the NPCA PCH, after performing a random backoff, to transmit a frame (not shown in FIG. 11 ) on the NPCA PCH.

[0104] FIG. 12 illustrates an example 1200 that highlights a problem that may arise in existing NPCA operation. As shown in FIG. 12, example 1200 includes a STA 1202, an AP 1204, and a STA 1206. AP 1204 and STA 1206 may belong to the same BSS. STA 1202 may belong to a different BSS than AP 1204 and STA 1206. In an example, STA 1202 may be an AP STA or a non-AP STA. In an example, AP 1204 may be an AP STA, and STA 1206 may be a non-AP STA. In an example, where AP 1204 is an AP STA and STA 1206 is a non-AP STA, STA 1206 may be associated with AP 1204. In an example, AP 1204 and STA 1206 may support NPCA operation and may operate over a plurality of channels, including a primary channel (PCH), an NPCA primary channel (NPCA PCH), a first secondary channel (SCH1 ), and a second secondary channel (SCH2).

[0105] As shown in FIG. 12, example 1200 may begin with STA 1202 transmitting a frame 1210 on the PCH. By transmitting frame 1210, STA 1202 may obtain a TXOP on the PCH. Frame 1210 may be comprised in a PPDU comprising a TXOP duration field. The TXOP duration field may indicate a TXOP duration 1212. TXOP duration 1212 may indicate a duration that starts at the end of frame 1210 (e.g., starting at a time T1 ) and that ends at a time T2 as shown in FIG. 12. After transmitting frame 1210, STA 1202 may communicate via the PCH within TXOP duration 1212. In an example, STA 1202 may perform uplink and / or downlink communications as illustrated with a frame exchange 1214. In an example, where STA 1202 is an AP STA, STA 1202 may communicate with its associated STAs. In example 1200, frame exchange 1214 may extend to the end of TXOP duration 1212.

[0106] In an example, on receiving frame 1210, AP 1204 may determine that frame 1210 is carried in an inter-BSS PPDU (OBSS PPDU). As discussed above in relation to FIG. 11 and in accordance with NPCA operation, AP 1204 may set a NAV 1216 for the PCH based on TXOP duration 1212 and may switch to the NPCA PCH. In example 1200, AP 1204 may switch to the NPCA PCH at time T1 . In an example, AP 1204 may be configured to switch back to the PCH based on TXOP duration 1212 (OBSS NAV duration for AP 1204). In an example, AP 1204 may switch to the PCH by / before an end of TXOP duration 1212. In anDocket No.: 24-3062PCT example, AP 1204 may switch to the PCH before the end of TXOP duration 1212, e.g., before the end of TXOP duration 1212 by an NPCA switch back delay field value (e.g., indicated in an NPCA Operation Information / Parameters field of AP 1204). In example 1200, AP 1204 may switch to the PCH by / at the end of TXOP duration 1212 (e.g., at time T2). In an example, AP 1204 may set / initialize / start (e.g., at time T1) a first timer for switching from the NPCA PCH to the PCH based on TXOP duration 1212. After switching to the NPCA PCH and before the expiry of the first timer (e.g., before time T2), AP 1204 may be involved in uplink and / or downlink communications with its associated STAs on the NPCA PCH.

[0107] In an example, on receiving frame 1210, STA 1206 may determine that frame 1210 is carried in an inter-BSS PPDU (OBSS PPDU). Based on supporting / enabling NPCA operation, STA 1206 may set a NAV 1218 for the PCH based on TXOP duration 1212 and may switch to the NPCA PCH for TXOP duration 1212 (OBSS NAV duration for STA 1206). In example 1200, STA 1206 may switch to the NPCA PCH at time T1. In an example, STA 1206 may be configured to switch back to the PCH based on TXOP duration 1212 (OBSS NAV duration for STA 1206). In an example, STA 1206 may switch to the PCH by / before an end of TXOP duration 1212. In an example, STA 1206 may switch to the PCH before the end of TXOP duration 1212, e.g., before the end of TXOP duration 1212 by an NPCA switch back delay field value (e.g., indicated in an NPCA Operation Information / Parameters field of AP 1204). In example 1200, STA 1206 may switch to the PCH by / at the end of TXOP duration 1212 (e.g., at time T2). In an example, STA 1206 may set / initialize / start (e.g., at time T1 ) a second timer for switching from the NPCA PCH to the PCH based on TXOP duration 1212. After switching to the NPCA PCH and before the expiry of the second timer (e.g., before time T2), STA 1206 may be involved in uplink and / or downlink communications with AP 1204 on the NPCA PCH.

[0108] In an example, after switching to the NPCA PCH, AP 1204 may start a "MediumSyncDelay” timer for the medium synchronization duration of the NPCA PCH, and if the NPCA PCH is idle (at / after expiration of the MediumSyncDelay timer), AP 1204 may access the NPCA PCH to transmit a frame on the NPCA PCH. In example 1200, AP 1204 may transmit a frame 1220 to STA 1206. In an example, frame 1220 may be an initial control frame (ICF). In another example, frame 1220 may be a trigger frame. In another example, frame 1220 may be a request-to-send (RTS) frame. In response to frame 1220, STA 1206 may transmit a frame 1222 to STA 1206. In an example, where frame 1220 is an ICF, frame 1222 may be an initial control response frame (ICR). In another example, where frame 1220 is a trigger frame, frame 1222 may be a clear-to-send (CTS) frame. In another example, where frame 1220 is an RTS frame, frame 1222 may be a CTS frame. In an example, on receiving frame 1222, AP 1204 may transmit a frame 1224 to STA 1206. In an example, frame 1224 may comprise buffered data for STA 1206. On receiving frame 1224, STA 1206 may transmit a frame 1226 to AP 1204. In an example, frame 1226 may comprise a block acknowledgment (BA) frame.

[0109] In an example after receiving frame 1226, new data may arrive at AP 1204 for transmission to STA 1206. In an example, the new data may comprise data of a first category. In an example, the data of the first category may be data associated with low latency traffic. In an example, the data associated with low latencyDocket No.: 24-3062PCT traffic may be data associated with one or more of: a voice type access category (AC_VO) and a video type access category (AC_VI). In another example, the data associated with low latency traffic may be data associated with one or more traffic identifiers (TIDs) with values equal to 4, 5, 6, or 7.

[0110] According to existing NPCA operation, AP 1204 may determine whether AP 1204 may transmit the data of the first category on the NPCA PCH before the expiry of the first timer (e.g ., before time T2). If a duration required to transmit the data of the first category exceeds a remaining time of the first timer, AP 1204 determines not to transmit the data of the first category on the NPCA PCH. As such, AP 1204 switches to the PCH at / by time T2 and contends for the PCH to transmit the data of the first category to STA 1206 after switching to the PCH. In an example, contending for a channel may comprise initiating a backoff counter (e.g., EDCA counter) in order to gain control of the channel. In an example, as illustrated in FIG. 12, AP 1204 may not gain control of the PCH (immediately after switching to the PCH) due to the PCH being busy. In an example, the PCH may be busy due to another OBSS STA communicating on the PCH when AP 1204 switches to the PCH. The OBSS STA may be hidden to STA 1202 but may be in the communication range of AP 1204. In another example, another STA associated with AP 1204 may gain control of the PCH after switching to the PCH. As such, AP 1204 may not be able to transmit the data of the first category to STA 1206 timely, and the data may be discarded or lost.

[0111] Embodiments of the present disclosure, as further described below, address the above-discussed problem of existing technologies. In an aspect, an AP determines whether a first duration, required to transmit data of a first category, buffered at the AP, on a first channel (e.g., NPCA PCH), exceeds / is greater than a first value based on a second duration indicated in a PPDU received via a second channel (e.g., PCH). In an embodiment, the first value is a remaining time of a timer set / initialized by the AP for switching from the first channel to the second channel based on the second duration. In an embodiment, the second duration indicated in the PPDU comprises a second value indicated in a duration field of a PHY header or a MAC header of the PPDU. When the first duration exceeds the first value, the AP may transmit the data of the first category and then switch, at a first time, from the first channel to the second channel. In an embodiment, the first time is based on the first duration. As such, the AP may transmit the data of the first category timely without switching to the second channel. This addresses the above-described problem in which the transmission of the data of the first category may be delayed and may be discarded or lost.

[0112] In another aspect, the AP determines that a PPDU being received via a PCH comprises an inter- BSS PPDU and switches from the PCH to an NPCA PCH based on the determining. In an embodiment, the AP sets a timer for switching back from the NPCA PCH to the PCH based on a duration indicated in the PPDU and a switch back delay of the AP. In an embodiment, before expiration of the timer, the AP transmits, via the NPCA PCH, a frame to a station (STA) associated with the AP. In an embodiment, the frame may comprise a portion of data that may be transmitted to the STA before expiration of the timer. In an embodiment, the AP transmits the frame to the STA after a switching delay time of the STA has elapsed sinceDocket No.: 24-3062PCT the STA / AP has initiated the switching to the NPCA PCH. In an embodiment, the AP switches from the NPCA PCH to the PCH when / before the timer expires. In an embodiment, the AP may be an AP STA or a non-AP STA. In an embodiment, the STA may be an AP STA or a non-AP STA.

[0113] FIG. 13 shows an example 1300 that illustrates an example NPCA operation according to an embodiment. As shown in FIG. 13, example 1300 includes a STA 1302, an AP 1304, and a STA 1306. AP 1304 and STA 1306 may belong to the same BSS. STA 1302 may belong to a different BSS than AP 1304 and STA 1306. In an embodiment, STA 1302 may be an AP STA or a non-AP STA. In an embodiment, AP 1304 may be an AP STA, and STA 1306 may be a non-AP STA. In an embodiment, where AP 1304 is an AP STA and STA 1306 is a non-AP STA, STA 1306 may be associated with AP 1304. In an embodiment, AP 1304 and STA 1306 may 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).

[0114] As shown in FIG. 13, example 1300 may begin with STA 1302 transmitting a frame 1310 on the PCH. By transmitting frame 1310, STA 1302 may obtain a TXOP on the PCH. Frame 1310 may be comprised in a PPDU comprising a TXOP duration field. The TXOP duration field may indicate a TXOP duration 1312. In an embodiment, the TXOP duration field comprises a duration field of a physical layer (PHY) header of the PPDU or of a medium access control (MAC) header of the PPDU. TXOP duration 1312 may indicate a duration that starts at the end of frame 1310 (e.g., starting at a time T1 ) and that ends at a time T2 as shown in FIG. 13. After transmitting frame 1310, STA 1302 may communicate via the PCH within TXOP duration 1312. In an embodiment, STA 1302 may perform uplink and / or downlink communications as illustrated with a frame exchange 1314. In an embodiment, where STA 1302 is an AP STA, STA 1302 may communicate with its associated STAs. In example 1300, frame exchange 1314 may extend to the end of TXOP duration 1312.

[0115] In an embodiment, on receiving frame 1310 via the PCH, AP 1304 may determine that frame 1310 is carried in an inter-BSS PPDU (OBSS PPDU). As discussed above in relation to FIG. 11 and in accordance with NPCA operation, AP 1304 may set a NAV 1316 for the PCH based on TXOP duration 1312 and may switch to the NPCA PCH based on the determining that the PPDU being received via the PCH comprises an inter-BSS PPDU. In example 1300, AP 1304 may switch to the NPCA PCH at time T1 . In an embodiment, AP 1304 may be configured to switch back to the PCH based on TXOP duration 1312 (OBSS NAV duration for AP 1304). In an embodiment, AP 1304 may switch to the PCH by / before an end of TXOP duration 1312. In an embodiment, AP 1304 may switch to the PCH before the end of TXOP duration 1312, e.g., before the end of TXOP duration 1312 by an NPCA switch back delay field value (e.g., indicated in an NPCA Operation Information / Parameters field of AP 1304). In example 1300, AP 1304 may switch to the PCH by / at the end of TXOP duration 1312 (e.g., at time T2). In an embodiment, AP 1304 may set / initialize / start (e.g., at T1 ) a first timer for switching from the NPCA PCH to the PCH based on TXOP duration 1312. In anotherDocket No.: 24-3062PCT embodiment, AP 1304 may set / initialize / start (e.g., at T1 ) a first timer for switching from the NPCA PCH to the PCH based on TXOP duration 1312 and the NPCA switch back delay value of AP 1304. After switching to the NPCA PCH and before the expiry of the first timer (e.g., before time T2), AP 1304 may be involved in uplink and / or downlink communications with its associated STAs on the NPCA PCH. In an embodiment, AP 1304 may transmit via the NPCA PCH one or more frames to a STA associated with AP 1304 (e.g., STA 1306) before expiration of the first timer.

[0116] In an embodiment, on receiving frame 1310 via the PCH, STA 1306 may determine that frame 1310 is carried in an inter-BSS PPDU (OBSS PPDU). Based on supporting / enabling NPCA operation, STA 1306 may set a NAV 1318 for the PCH based on TXOP duration 1312 and may switch to the NPCA PCH based on the determining that the PPDU being received via the PCH comprises an inter-BSS PPDU. In example 1300, STA 1306 may switch to the NPCA PCH at time T1. In an embodiment, STA 1306 may be configured to switch back to the PCH based on TXOP duration 1312 (OBSS NAV duration for STA 1306). In an embodiment, STA 1306 may switch to the PCH by / before an end of TXOP duration 1312. In an embodiment, STA 1306 may switch to the PCH before the end of TXOP duration 1312, e.g., before the end of TXOP duration 1312 by an NPCA switch back delay field value (e.g., indicated in an NPCA Operation Information / Parameters field of AP 1304). In example 1300, STA 1306 may switch to the PCH by / at the end of TXOP duration 1312 (e.g., at time T2). In an embodiment, STA 1306 may set / initialize / start (e.g., at time T1) a second timer for switching from the NPCA PCH to the PCH based on TXOP duration 1312. In another embodiment, STA 1306 may set / initialize / start (e.g., at T1) a second timer for switching from the NPCA PCH to the PCH based on TXOP duration 1312 and the NPCA switch back delay value of STA 1306. After switching to the NPCA PCH and before the expiry of the second timer (e g., before time T2), STA 1306 may be involved in uplink and / or downlink communications with AP 1304 on the NPCA PCH.

[0117] In an embodiment, after switching to the NPCA PCH, AP 1304 may start a “MediumSyncDelay” timer for the medium synchronization duration of the NPCA PCH, and if the NPCA PCH is idle (at / after expiration of the MediumSyncDelay timer), AP 1304 may access the NPCA PCH to transmit a frame on the NPCA PCH. In example 1300, AP 1304 may transmit a frame 1320 to STA 1306. In an embodiment, frame 1320 may comprise an initial control frame (IGF). In another embodiment, frame 1320 may comprise a trigger frame. In another embodiment, frame 1320 may comprise a request-to-send (RTS) frame. In response to frame 1320, STA 1306 may transmit a frame 1322 to STA 1306. In an embodiment, where frame 1320 is an ICF, frame 1322 may comprise an initial control response frame (ICR). In another embodiment, where frame 1320 is a trigger frame, frame 1322 may comprise a clear-to-send (CTS) frame. In another embodiment, where frame 1320 is an RTS frame, frame 1322 may comprise a CTS frame. In an embodiment, on receiving frame 1322, AP 1304 may transmit a frame 1324 to STA 1306. In an embodiment, AP 1304 transmits frame 1324 via the NPCA PCH before expiration of the first timer. In an embodiment, frame 1324 may comprise buffered dataDocket No.: 24-3062PCT for STA 1306. On receiving frame 1324, STA 1306 may transmit a frame 1326 to AP 1304. In an embodiment, frame 1326 may comprise a block acknowledgment (BA) frame.

[0118] In an embodiment, after receiving frame 1326, new data may arrive at AP 1304 for transmission to STA 1306. In an embodiment, the new data may comprise data of a first category. In an embodiment, the data of the first category may comprise one or more data frames. In an embodiment, the one or more data frames are addressed / transmitted to one or more stations (STAs).

[0119] In an embodiment, the data of the first category may comprise data associated with low latency traffic. In an embodiment, the data associated with low latency traffic may comprise data associated with one or more of: a voice type access category (AC_VO) and a video type access category (AC_VI). In another embodiment, the data associated with low latency traffic may comprise data associated with one or more traffic identifiers (TIDs) with values equal to 4, 5, 6, or 7.

[0120] In another embodiment, the data of the first category may not be data associated with low latency traffic only. In an embodiment, the data of the first category may comprise data associated with one or more of: a voice type access category (AC_VO), a video type access category (AC_VI), a best effort type access category (AC_BE), and a background type access category (AC_BK). In an embodiment, the data of the first category may comprise data associated with one or more traffic identifiers (TIDs) with values equal to 0, 1 , 2, 3, 4, 5, 6, or 7.

[0121] In an embodiment, AP 1304 may determine whether AP 1304 may transmit the data of the first category before the expiry of the first timer (e.g., before time T2). As such, AP 1304 may determine a first duration, where the first duration is a duration required to transmit the data of the first category, buffered at the AP, on the NPCA PCH. AP 1304 may then compare the first duration to a value based on TXOP duration 1312 indicated in frame 1310 comprised in the PPDU received via the PCH. In an embodiment, the value may be a remaining time of the first timer, where the first timer is set based on TXOP duration 1312 and expires at time T2. In an embodiment, the first duration may exceed / be greater than the value (the remaining time until time T2). Based on determining that the first duration exceeds / is greater than the value, AP 1304 may determine a first time in order to switch from the NPCA PCH to the PCH at the first time. In an embodiment, AP 1304 determines the first time after / based on arrival at AP 1304 of the data of the first category. In an embodiment, the first time is based on the first duration. In an embodiment, the first duration may comprise a transmission duration of the data via one or more data frames, a duration of one or more short interframe spacings (SIFSs), and a transmission duration of one or more response frames in response to the data. In example 1300, the first duration may comprise the duration of a frame 1328 (frame 1328 may comprise the data of the first category). In an embodiment, AP 1304 updates the first timer based on the first time (based on determining that the first duration exceeds the value of the timer), before transmitting frame 1328 via the NPCA PCH. In an embodiment, the first time may be a time T3 as illustrated in FIG. 13. In an embodiment, after updating the first timer, AP 1304 transmits frame 1328. In another embodiment (not shownDocket No.: 24-3062PCT in FIG. 13), based on determining that the first duration does not exceed / is not greater than the value, AP 1304 may transmit frame 1328 via the NPCA PCH without updating the first timer. In another embodiment (not shown in FIG. 13), AP 1304 may not update the first timer although the first duration exceeds / is greater than the value of the first timer. Instead, AP 1304 may transmit to STA 1306 a frame comprising a portion of frame 1328 via the NPCA PCH before expiration of the first timer. As such, AP 1304 switches from the NPCA PCH to the PCH when the first timer expires. Similarly, STA 1306 switches from the NPCA PCH to the PCH when the second timer expires.

[0122] In an embodiment, frame 1328 comprises / indicates the first time. In an embodiment, the first time may be provided / comprised in a duration field of a PHY header of frame 1328. In an embodiment, frame 1328 may comprise a broadcast frame. In another embodiment, frame 1328 may comprise a unicast frame addressed to a STA. In example 1300, frame 1328 may comprise a unicast frame addressed to STA 1306. In an embodiment, frame 1328 may further comprise an indication that frame 1328 comprises / indicates the first time. In an embodiment, the indication may be provided / comprised in the PHY header of frame 1328. In an embodiment, frame 1328 may further comprise the data of the first category. In an embodiment, frame 1328 may comprise a QoS data frame.

[0123] In an embodiment, on receiving frame 1328 addressed to STA 1306, STA 1306 may decode the PHY header of frame 1328. In an embodiment, STA 1306 may obtain the indication that frame 1328 comprises / indicates the first time. Based on obtaining the indication, STA 1306 may locate the first time in frame 1328 and may update the second timer based on the first time (e.g., T3). Based on updating the second timer, STA 1306 is / becomes configured to switch from the NPCA PCH to the PCH at the first time. In another embodiment, STA 1306 may obtain the first time provided in a duration field of the PHY header of frame 1328 and update the second timer based on the first time (e.g., T3) without obtaining the indication (e.g., frame 1328 may not comprise the indication). As such, STA 1306 remains on the NPCA PCH to receive the data of the first category comprised in frame 1328 and switches to the PCH at time T3 instead of time T2. In another embodiment (not shown in FIG. 13), the first time may also comprise a duration of a SIFS and a duration of a response frame to frame 1328. As such, STA 1306 may transmit the response frame before switching back to the PCH. In another embodiment (not shown in FIG. 13), another STA associated with AP 1304 may be configured to receive / decode frame 1328. The other STA may obtain the indication that frame 1328 comprises / indicates the first time, obtain the first time from frame 1328, and update its timer to switch back to the PCH based on the first time (e.g. at time T3). As such, the other STA switches from the NPCA PCH to the PCH at the same time as AP 1304 and STA 1306. As illustrated in example 1300, by switching to the PCH at time T3 instead of time T2, AP 1304 transmits the data of the first category timely via the NPCA PCH and avoids switching to a busy PCH in which case AP 1304 may not be able to transmit the data of the first category in a timely manner. Potential delay or discarding of the data of the first category may therefore be avoided.Docket No.: 24-3062PCT

[0124] FIG. 14 shows an example 1400 that illustrates an example NPCA operation according to an embodiment. As shown in FIG. 14, example 1400 includes a STA 1402, an AP 1404, a STA 1406 and a STA 1408. AP 1404, STA 1406, and STA 1408 may belong to the same BSS. STA 1402 may belong to a different BSS than AP 1404, STA 1406, and STA 1408. In an embodiment, STA 1402 may be an AP STA or a non- AP STA. In an embodiment, AP 1404 may be an AP STA, and STAs 1406 and 1408 may be non-AP STAs. In an embodiment, where AP 1404 is an AP STA and STAs 1406 and 1408 are non-AP STAs, STAs 1406 and 1408 may be associated with AP 1404. In an embodiment, AP 1404, STA 1406, and STA 1408 may 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) (SCH2 is not shown in FIG. 14 for simplification purposes).

[0125] As shown in FIG. 14, example 1400 may begin with STA 1402 transmitting a frame 1410 on the PCH. By transmitting frame 1410, STA 1402 may obtain a TXOP on the PCH. Frame 1410 may be comprised in a PPDU comprising a TXOP duration field. The TXOP duration field may indicate a TXOP duration 1412. In an embodiment, the TXOP duration field comprises a duration field of a physical layer (PHY) header of the PPDU or of a medium access control (MAC) header of the PPDU. TXOP duration 1412 may indicate a duration that starts at the end of frame 1410 (e.g ., starting at a time T1 ) and that ends at a time T2 as shown in FIG. 14. After transmitting frame 1410, STA 1402 may communicate via the PCH within TXOP duration 1412. In an embodiment, STA 1402 may perform uplink and / or downlink communications as illustrated with a frame exchange 1414. In an embodiment, where STA 1402 is an AP STA, STA 1402 may communicate with its associated STAs. In example 1400, frame exchange 1414 may extend to the end of TXOP duration 1412.

[0126] In an embodiment, on receiving frame 1410 via the PCH, AP 1404 may determine that frame 1410 is carried in an inter-BSS PPDU (OBSS PPDU). As discussed above in relation to FIG. 11 and in accordance with NPCA operation, AP 1404 may set a NAV 1416 for the PCH based on TXOP duration 1412 and may switch to the NPCA PCH based on the determining that the PPDU being received via the PCH comprises an inter-BSS PPDU. In example 1400, AP 1404 may switch to the NPCA PCH at time T1 . In an embodiment, AP 1404 may be configured to switch back to the PCH based on TXOP duration 1412 (OBSS NAV duration for AP 1404). In an embodiment, AP 1404 may switch to the PCH by / before an end of TXOP duration 1412. In an embodiment, AP 1404 may switch to the PCH before the end of TXOP duration 1412, e.g., before the end of TXOP duration 1412 by an NPCA switch back delay field value (e.g., indicated in an NPCA Operation Information / Parameters field of AP 1404). In example 1400, AP 1404 may switch to the PCH by / at the end of TXOP duration 1412 (e.g., at time T2). In an embodiment, AP 1404 may set / initialize / start (e.g., at T1) a first timer for switching from the NPCA PCH to the PCH based on TXOP duration 1412. In another embodiment, AP 1404 may set / initialize / start (e.g., at T1 ) a first timer for switching from the NPCA PCH to the PCH based on TXOP duration 1412 and the NPCA switch back delay value of AP 1404. After switchingDocket No.: 24-3062PCT to the NPCA PCH and before the expiry of the first timer (e.g., before time T2), AP 1404 may be involved in uplink and / or downlink communications with its associated STAs on the NPCA PCH. In an embodiment, AP 1404 may transmit via the NPCA PCH one or more frames to one or more STAs associated with AP 1404 (e.g., STA 1406 and / or STA 1408) before expiration of the first timer.

[0127] In an embodiment, on receiving frame 1410 via the PCH, STA 1406 / 1408 may determine that frame 1410 is carried in an inter-BSS PPDU (OBSS PPDU). Based on supporting / enabling NPCA operation, STA 1406 / 1408 may set a NAV 1418 / 1419 for the PCH based on TXOP duration 1412 and may switch to the NPCA PCH based on the determining that the PPDU being received via the PCH comprises an inter-BSS PPDU. In example 1400, STA 1406 / 1408 may switch to the NPCA PCH at time T1. In an embodiment, STA 1406 / 1408 may be configured to switch back to the PCH based on TXOP duration 1412 (OBSS NAV duration for STA 1406 / 1408). In an embodiment, STA 1406 / 1408 may switch to the PCH by / before an end of TXOP duration 1412. In an embodiment, STA 1406 / 1408 may switch to the PCH before the end of TXOP duration 1412, e.g., before the end of TXOP duration 1412 by an NPCA switch back delay field value (e.g., indicated in an NPCA Operation Information / Parameters field of AP 1404). In example 1400, STA 1406 / 1408 may switch to the PCH by / at the end of TXOP duration 1412 (e.g., at time T2). In an embodiment, STA 1406 / 1408 may set / initialize / start (e.g., at time T1 ) a second / third timer for switching from the NPCA PCH to the PCH based on TXOP duration 1412. In another embodiment, STA 1406 / 1408 may set / initialize / start (e.g., at T1) a second / third timer for switching from the NPCA PCH to the PCH based on TXOP duration 1412 and the NPCA switch back delay value of STA 1406 / 1408. After switching to the NPCA PCH and before the expiry of the second / third timer (e.g., before time T2), STA 1406 / 1408 may be involved in uplink and / or downlink communications with AP 1404 on the NPCA PCH.

[0128] In an embodiment, after switching to the NPCA PCH, AP 1404 may start a "MediumSyncDelay” timer for the medium synchronization duration of the NPCA PCH, and if the NPCA PCH is idle (at / after expiration of the MediumSyncDelay timer), AP 1404 may access the NPCA PCH to transmit a frame on the NPCA PCH. In example 1400, AP 1404 may transmit a frame 1420 to STA 1406. In another embodiment (not shown in FIG. 14), AP 1404 may transmit a frame 1420 to STA 1406 and / or STA 1408. In an embodiment, frame 1420 may comprise an initial control frame (ICF). In another embodiment, frame 1420 may comprise a trigger frame. In another embodiment, frame 1420 may comprise a request-to-send (RTS) frame. In response to frame 1420, STA 1406 may transmit a frame 1422 to AP 1404. In another embodiment (not shown in FIG. 14), if frame 1420 is addressed to STA 1408, STA 1408 may transmit a frame to AP 1404 in response to frame 1420. In an embodiment, where frame 1420 is an ICF, frame 1422 may comprise an initial control response frame (ICR). In another embodiment, where frame 1420 is a trigger frame, frame 1422 may comprise a clear-to-send (CTS) frame. In another embodiment, where frame 1420 is an RTS frame, frame 1422 may comprise a CTS frame. In an embodiment, on receiving frame 1422, AP 1404 may transmit a frame 1424 to STA 1406. In an embodiment, AP 1404 transmits frame 1424 via the NPCA PCH beforeDocket No.: 24-3062PCT expiration of the first timer. In an embodiment, frame 1424 may comprise buffered data for STA 1406. On receiving frame 1424, STA 1406 may transmit a frame 1426 to AP 1404. In an embodiment, frame 1426 may comprise a block acknowledgment (BA) frame.

[0129] In an embodiment, after receiving frame 1426, new data may arrive at AP 1404 for transmission to STA 1406 and / or STA 1408. In an embodiment, the new data may comprise data of a first category. In an embodiment, the data of the first category may comprise one or more data frames. In an embodiment, the one or more data frames are addressed / transmitted to one or more stations (STAs).

[0130] In an embodiment, the data of the first category may comprise data associated with low latency traffic. In an embodiment, the data associated with low latency traffic may comprise data associated with one or more of: a voice type access category (AC_VO) and a video type access category (AC_VI). In another embodiment, the data associated with low latency traffic may comprise data associated with one or more traffic identifiers (TIDs) with values equal to 4, 5, 6, or 7.

[0131] In another embodiment, the data of the first category may not be data associated with low latency traffic only. In an embodiment, the data of the first category may comprise data associated with one or more of: a voice type access category (AC_VO), a video type access category (AC_VI), a best effort type access category (AC_BE), and a background type access category (AC_BK). In an embodiment, the data of the first category may comprise data associated with one or more traffic identifiers (TIDs) with values equal to 0, 1 , 2, 3, 4, 5, 6, or 7.

[0132] In an embodiment, AP 1404 may determine whether AP 1404 may transmit the data of the first category before the expiry of the first timer (e.g., before time T2). As such, AP 1404 may determine a first duration, where the first duration is a duration required to transmit the data of the first category, buffered at the AP, on the NPCA PCH. AP 1404 may then compare the first duration to a value based on TXOP duration 1412 indicated in frame 1410 comprised in the PPDU received via the PCH. In an embodiment, the value may be a remaining time of the first timer, where the first timer is set based on TXOP duration 1412 and expires at time T2. In an embodiment, the first duration may exceed / be greater than the value (the remaining time until time T2). Based on determining that the first duration exceeds / is greater than the value, AP 1404 may determine a first time in order to switch from the NPCA PCH to the PCH at the first time. In an embodiment, AP 1404 determines the first time after / based on arrival at AP 1404 of the data of the first category. In an embodiment, the first time is based on the first duration. In an embodiment, the first duration may comprise a transmission duration of the data via one or more data frames, a duration of one or more short interframe spacings (SIFSs), and a transmission duration of one or more response frames in response to the data. In example 1400, the first duration may comprise the duration of a frame 1430, a frame 1432, a frame 1434, a frame 1436, and a duration of SIPS before the transmission of each of frame 1430, 1432, 1434, and 1436. In an embodiment, frame 1430 and frame 1434 may comprise the data of the first categoryDocket No.: 24-3062PCT addressed to STA 1406 and STA 1408, respectively. In an embodiment, frame 1432 and frame 1436 may comprise response frames to frame 1430 and frame 1434, respectively.

[0133] In an embodiment, before transmitting the data of the first category, AP 1404 may be configured to transmit a frame 1428 to announce the first time. This allows STAs associated with AP 1404 to determine the switching time from the NPCA PCH to the PCH. In an embodiment, AP 1404 may calculate the first time considering the first duration and a duration for the transmission of frame 1428. In an embodiment, AP 1404 updates the first timer based on the first time (based on determining that the first duration exceeds the value of the timer), before transmitting frame 1428 via the NPCA PCH. In an embodiment, the first time may be a time T3 as illustrated in FIG. 14. In an embodiment, after updating the first timer, AP 1404 transmits frame 1428. In another embodiment (not shown in FIG. 14), based on determining that the first duration does not exceed / is not greater than the value, AP 1404 may transmit frame 1430 and frame 1434 via the NPCA PCH without updating the first timer. In another embodiment (not shown in FIG. 14), AP 1404 may not update the first timer although the first duration exceeds / is greater than the value of the first timer. Instead, AP 1404 may transmit to STA 1406 and / or STA 1408 one or more frames comprising portions of frames 1430 and 1434 via the NPCA PCH before expiration of the first timer. As such, AP 1404 switches from the NPCA PCH to the PCH when the first timer expires. Similarly, STA 1406 and STA 1408 switch from the NPCA PCH to the PCH when the second timer and the third timer expire.

[0134] In an embodiment, frame 1428 comprises / indicates the first time. In an embodiment, the first time may be provided / comprised in a duration field of a PHY header of frame 1428. In an embodiment, frame 1428 may comprise a broadcast frame. In another embodiment, frame 1428 may comprise a unicast frame addressed to a STA. In example 1400, frame 1428 may comprise a broadcast frame. As such, all STAs associated with AP 1404 (not only the STAs that are recipients of the data of the first category, e.g ., not only STA 1406 and STA 1408) may update their timers for switching from the NPCA PCH to the PCH based on frame 1428. In an embodiment, frame 1428 may further comprise an indication that frame 1428 comprises / indicates the first time. In an embodiment, the indication may be provided / comprised in the PHY header of frame 1428. In an embodiment, frame 1428 may further comprise a management frame, an action frame, a control frame, a quality of service (QoS) null frame, or a QoS data frame.

[0135] In an embodiment, on receiving frame 1428, STA 1406 / 1408 may decode the PHY header of frame 1428. In an embodiment, STA 1406 / 1408 may obtain the indication that frame 1428 comprises / indicates the first time. Based on obtaining the indication, STA 1406 / 1408 may locate the first time in frame 1428 and may update the second / third timer based on the first time (e.g., T3). Based on updating the second / third timer, STA 1406 / 1408 is / becomes configured to switch from the NPCA PCH to the PCH at the first time. In another embodiment, STA 1406 / 1408 may obtain the first time provided in a duration field of the PHY header of frame 1428 and update the second / third timer based on the first time (e.g., T3) without obtaining the indication (e.g., frame 1428 may not comprise the indication). As such, STA 1406 / 1408 remains on the NPCA PCH, may orDocket No.: 24-3062PCT may not receive one or more frames from AP 1404 while remaining on the NPCA PCH until the second / third timer is expired, and switches to the PCH at time T3 instead of time T2.

[0136] In an embodiment, after transmitting frame 1428, AP 1404 may transmit to STA 1406 frame 1430 comprising the data of the first category. In response to frame 1430, AP 1404 may receive from STA 1406 frame 1432. After receiving frame 1432, AP 1404 may transmit to STA 1408 frame 1434 comprising the data of the first category. In response to frame 1434, AP 1404 may receive from STA 1408 frame 1436. In an embodiment, frame 1432 and frame 1436 may comprise BA frames. As illustrated in example 1400, by switching to the PCH at time T3 instead of time T2, AP 1404 transmits the data of the first category timely via the NPCA PCH to one or more stations and avoids switching to a busy PCH in which case AP 1404 may not be able to transmit the data of the first category in a timely manner. Potential delay or discarding of the data of the first category may therefore be avoided.

[0137] FIG. 15 shows an example 1500 that illustrates an example NPCA operation according to an embodiment. As shown in FIG. 15, example 1500 includes a STA 1502, an AP 1504, and a STA 1506. AP 1504 and STA 1506 may belong to the same BSS. STA 1502 may belong to a different BSS than AP 1504 and STA 1506. In an embodiment, STA 1502 may be an AP STA or a non-AP STA. In an embodiment, AP 1504 may be an AP STA, and STA 1506 may be a non-AP STA. In an embodiment, where AP 1504 is an AP STA and STA 1506 is a non-AP STA, STA 1506 may be associated with AP 1504. In an embodiment, AP 1504 and STA 1506 may 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).

[0138] As shown in FIG. 15, example 1500 may begin with STA 1502 transmitting a frame 1510 on the PCH. By transmitting frame 1510, STA 1502 may obtain a TXOP on the PCH. Frame 1510 may be comprised in a PPDU comprising a TXOP duration field. The TXOP duration field may indicate a TXOP duration 1512. In an embodiment, the TXOP duration field comprises a duration field of a physical layer (PHY) header of the PPDU or of a medium access control (MAC) header of the PPDU. TXOP duration 1512 may indicate a duration that starts at the end of frame 1510 (e.g., starting at a time T1 ) and that ends at a time T2 as shown in FIG. 15. After transmitting frame 1510, STA 1502 may communicate via the PCH within TXOP duration 1512. In an embodiment, STA 1502 may perform uplink and / or downlink communications as illustrated with a frame exchange 1514. In an embodiment, where STA 1502 is an AP STA, STA 1502 may communicate with its associated STAs. In example 1500, frame exchange 1514 may extend to the end of TXOP duration 1512.

[0139] In an embodiment, on receiving frame 1510 via the PCH, AP 1504 may determine that frame 1510 is carried in an inter-BSS PPDU (OBSS PPDU). As discussed above in relation to FIG. 11 and in accordance with NPCA operation, AP 1504 may set a NAV 1516 for the PCH based on TXOP duration 1512 and may switch to the NPCA PCH based on determining that the PPDU being received via the PCH comprises anDocket No.: 24-3062PCT inter-BSS PPDU. In example 1500, AP 1504 may switch to the NPCA PCH at time T1 . In an embodiment, AP 1504 may be configured to switch back to the PCH based on TXOP duration 1512 (OBSS NAV duration for AP 1504), e.g., at time T2. In an embodiment, AP 1504 may switch to the PCH by / before an end of TXOP duration 1512. In an embodiment, AP 1504 may switch to the PCH before the end of TXOP duration 1512, e.g., before the end of TXOP duration 1512 by an NPCA switch back delay field value (e.g., indicated in an NPCA Operation Information / Parameters field of AP 1504).

[0140] In an embodiment, at the time of switching from the PCH to the NPCA PCH, AP 1504 may have buffered data for transmission. For example, while AP 1504 is receiving frame 1510, new data may arrive at AP 1504 for transmission to STA 1506. In another embodiment (not shown in FIG. 15), the new data may arrive at AP 1504 for transmission to STA 1506 before receiving frame 1510 on the PCH, but AP 1504 may not have gained control of the PCH for the transmission of the new data. In an embodiment, the new data may comprise data of a first category. In an embodiment, the data of the first category may comprise one or more data frames. In an embodiment, the one or more data frames are addressed / transmitted to one or more stations (STAs).

[0141] In an embodiment, the data of the first category may comprise data associated with low latency traffic. In an embodiment, the data associated with low latency traffic may comprise data associated with one or more of: a voice type access category (AC_VO) and a video type access category (AC_VI). In another embodiment, the data associated with low latency traffic may comprise data associated with one or more traffic identifiers (TIDs) with values equal to 4, 5, 6, or 7.

[0142] In another embodiment, the data of the first category may not be data associated with low latency traffic only In an embodiment, the data of the first category may comprise data associated with one or more of: a voice type access category (AC_VO), a video type access category (AC_VI), a best effort type access category (AC_BE), and a background type access category (AC_BK). In an embodiment, the data of the first category may comprise data associated with one or more traffic identifiers (TIDs) with values equal to 0, 1 , 2, 3, 4, 5, 6, or 7.

[0143] In an embodiment, AP 1504 may determine a first duration, where the first duration is a duration required to transmit the data of the first category buffered at the AP. In an embodiment, where AP 1504 has data buffered for transmission at the time of switching to the NPCA PCH, AP 1504 may determine the first duration at the time of switching to the NPCA PCH.

[0144] In an embodiment, AP 1504 may be configured to switch to the PCH by / at the end of TXOP duration 1512 (e.g., at time T2), if the first duration is less than a value based on TXOP duration 1512 indicated in frame 1510 comprised in the PPDU received via the PCH. In an embodiment, the value based on TXOP duration 1512 may be the same as TXOP duration 1512 (or a remaining duration of TXOP duration 1512). As such, AP 1504 may transmit the data to STA 1506 via the NPCA PCH before switching to the PCH at time T2. On the other hand, if the first duration exceeds / is greater than the value based on TXOP durationDocket No.: 24-3062PCT1512, AP 1504 may be configured to determine a first time in order to switch from the NPCA PCH to the PCH at the first time. In an embodiment, when AP 1504 has buffered data for transmission at the time of switching to the NPCA PCH, AP 1504 may determine the first time at the time of switching to the NPCA PCH.

[0145] In example 1500, the first duration exceeds / is greater than the value based on TXOP duration 1512. As such, based on determining that the first duration exceeds / is greater than the value, AP 1504 determines the first time in order to switch from the NPCA PCH to the PCH at the first time. In an embodiment, determining the first time comprises determining the first time at the time of switching from the PCH to the NPCA PCH. In another embodiment, determining the first time comprises determining the first time a short inter-frame space (SIPS) after switching from the PCH to the NPCA PCH. In an embodiment, determining the first time is before an end of the TXOP duration 1512. In an embodiment, the first time is based on the first duration. In an embodiment, the first duration may comprise a transmission duration of the data via one or more data frames, a duration of one or more short interframe spacings (SIFSs), and a transmission duration of one or more response frames in response to the data. In example 1500, the first duration may comprise the duration of a frame 1524 (frame 1524 may comprise the data of the first category), and a duration of an ICF-ICR exchange between AP 1504 and STA 1506 as further described below. In an embodiment, AP 1504 sets / initializes / starts a first timer for switching from the NPCA PCH to the PCH based on the first time. In an embodiment, the first time may be a time T3 as illustrated in FIG. 15. After switching to the NPCA PCH and before the expiry of the first timer (e.g., before time T3), AP 1504 may be involved in uplink and / or downlink communications with its associated STAs on the NPCA PCH. In another embodiment (not shown in FIG. 15), AP 1504 may set / initialize / start (e.g., at T1 ) a first timer for switching from the NPCA PCH to the PCH based on TXOP duration 1512 and the NPCA switch back delay value of AP 1504. In an embodiment, AP 1504 may transmit via the NPCA PCH one or more frames to a STA associated with AP 1504 (e.g., STA 1506) before expiration of the first timer.

[0146] In an embodiment, on receiving frame 1510 via the PCH, STA 1506 may determine that frame 1510 is carried in an inter-BSS PPDU (OBSS PPDU). Based on supporting / enabling NPCA operation, STA 1506 may set a NAV 1518 for the PCH based on TXOP duration 1512 and may switch to the NPCA PCH based on the determining that the PPDU being received via the PCH comprises an inter-BSS PPDU. In example 1500, STA 1506 may switch to the NPCA PCH at time T1. In an embodiment, STA 1506 may be configured to switch back to the PCH based on TXOP duration 1512 (OBSS NAV duration for STA 1506). In an embodiment, STA 1506 may switch to the PCH by / before an end of TXOP duration 1512. In an embodiment, STA 1506 may switch to the PCH before the end of TXOP duration 1512, e.g., before the end of TXOP duration 1512 by an NPCA switch back delay field value (e.g., indicated in an NPCA Operation Information / Parameters field of AP 1504). In example 1500, STA 1506 may be configured to switch to the PCH by / at the end of TXOP duration 1512 (e.g., at time T2). In an embodiment, STA 1506 may set / initialize / start (e.g., at time T1 ) a second timer for switching from the NPCA PCH to the PCH based onDocket No.: 24-3062PCTTXOP duration 1512. In another embodiment, STA 1506 may set / initialize / start (e.g., at T1) a second timer for switching from the NPCA PCH to the PCH based on TXOP duration 1512 and the NPCA switch back delay value of STA 1506. After switching to the NPCA PCH and before the expiry of the second timer (e g., before time T2), STA 1506 may be involved in uplink and / or downlink communications with AP 1504 on the NPCA PCH.

[0147] In an embodiment, after switching to the NPCA PCH, AP 1504 may start a “MediumSyncDelay” timer for the medium synchronization duration of the NPCA PCH, and if the NPCA PCH is idle (at / after expiration of the MediumSyncDelay timer), AP 1504 may access the NPCA PCH to transmit a frame on the NPCA PCH. In example 1500, AP 1504 may transmit a frame 1520 to STA 1506. In an embodiment, frame 1520 may comprise an initial control frame (IGF). In another embodiment, frame 1520 may comprise a trigger frame. In another embodiment, frame 1520 may comprise a request-to-send (RTS) frame. In response to frame 1520, STA 1506 may transmit a frame 1522 to STA 1506. In an embodiment, where frame 1520 is an ICF, frame 1522 may comprise an initial control response frame (ICR). In another embodiment, where frame 1520 is a trigger frame, frame 1522 may comprise a clear-to-send (CTS) frame. In another embodiment, where frame 1520 is an RTS frame, frame 1522 may comprise a CTS frame. In an embodiment, on receiving frame 1522, AP 1504 may transmit frame 1524 to STA 1506. In an embodiment, AP 1504 transmits frame 1524 via the NPCA PCH before expiration of the first timer. In an embodiment, frame 1524 comprises the data of the first category. In an embodiment, frame 1524 may comprise a QoS data frame.

[0148] In an embodiment, frame 1524 further comprises / indicates the first time. In an embodiment, the first time may be provided / comprised in a duration field of a PHY header of frame 1524. In an embodiment, frame 1524 may comprise a broadcast frame. In another embodiment, frame 1524 may comprise a unicast frame addressed to a STA. In example 1500, frame 1524 may comprise a unicast frame addressed to STA 1506. In an embodiment, frame 1524 may further comprise an indication that frame 1524 comprises / indicates the first time. In an embodiment, the indication may be provided / comprised in the PHY header of frame 1524. In another embodiment (not shown in FIG. 15), AP 1504 may have set / initialized / started (e.g., at T1 ) the first timer for switching from the NPCA PCH to the PCH based on TXOP duration 1512 and the NPCA switch back delay value of AP 1504. As such, AP 1504 may transmit to STA 1506 a frame comprising a portion of frame 1524 via the NPCA PCH before expiration of the first timer. AP 1504 then switches from the NPCA PCH to the PCH when the first timer expires. Similarly, STA 1506 switches from the NPCA PCH to the PCH when the second timer expires.

[0149] In an embodiment, on receiving frame 1524 addressed to STA 1506, STA 1506 may decode the PHY header of frame 1524. In an embodiment, STA 1506 may obtain the indication that frame 1524 comprises / indicates the first time. Based on obtaining the indication, STA 1506 may locate the first time in frame 1524 and may update the second timer based on the first time (e.g., T3). Based on updating the second timer, STA 1506 is / becomes configured to switch from the NPCA PCH to the PCH at the first time. In anotherDocket No.: 24-3062PCT embodiment, STA 1506 may obtain the first time provided in a duration field of the PHY header of frame 1524 and update the second timer based on the first time (e.g., T3) without obtaining the indication (e.g., frame 1524 may not comprise the indication). As such, STA 1506 remains on the NPCA PCH to receive the data of the first category comprised in frame 1524 and switches to the PCH at time T3 instead of time T2. In another embodiment (not shown in FIG. 15), the first time may also comprise a duration of a SIFS and a duration of a response frame to frame 1524. As such, STA 1506 may transmit the response frame before switching back to the PCH. In another embodiment (not shown in FIG. 15), another STA associated with AP 1504 may be configured to receive / decode frame 1524. The other STA may obtain the indication that frame 1524 comprises / indicates the first time, obtain the first time from frame 1524, and update its timer to switch back to the PCH based on the first time (e.g. at time T3). As such, the other STA switches from the NPCA PCH to the PCH at the same time as AP 1504 and STA 1506. As illustrated in example 1500, AP 1504 transmits the data of the first category timely via the NPCA PCH. After determining the time required for transmission of the data of the first category to exceed TXOP duration 1512, AP 1504 switches from the NPCA PCH to the PCH at the first time, where the first time is based on the time required for transmission of the data and is after TXOP duration 1512. As such, potential delay or discarding of the data may be avoided.

[0150] FIG. 16 shows an example 1600 that illustrates an example NPCA operation according to an embodiment. As shown in FIG. 16, example 1600 includes a STA 1602, an AP 1604, a STA 1606 and a STA 1608. AP 1604, STA 1606, and STA 1608 may belong to the same BSS. STA 1602 may belong to a different BSS than AP 1604, STA 1606, and STA 1608. In an embodiment, STA 1602 may be an AP STA or a non- AP STA. In an embodiment, AP 1604 may be an AP STA, and STAs 1606 and 1608 may be non-AP STAs. In an embodiment, where AP 1604 is an AP STA and STAs 1606 and 1608 are non-AP STAs, STAs 1606 and 1608 may be associated with AP 1604. In an embodiment, AP 1604, STA 1606, and STA 1608 may 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) (SCH2 is not shown in FIG. 16 for simplification purposes).

[0151] As shown in FIG. 16, example 1600 may begin with STA 1602 transmitting a frame 1610 on the PCH. By transmitting frame 1610, STA 1602 may obtain a TXOP on the PCH. Frame 1610 may be comprised in a PPDU comprising a TXOP duration field. The TXOP duration field may indicate a TXOP duration 1612. In an embodiment, the TXOP duration field comprises a duration field of a physical layer (PHY) header of the PPDU or of a medium access control (MAC) header of the PPDU. TXOP duration 1612 may indicate a duration that starts at the end of frame 1610 (e.g., starting at a time T1 ) and that ends at a time T2 as shown in FIG. 16. After transmitting frame 1610, STA 1602 may communicate via the PCH within TXOP duration 1612. In an embodiment, STA 1602 may perform uplink and / or downlink communications as illustrated with a frame exchange 1614. In an embodiment, where STA 1602 is an AP STA, STA 1602 may communicateDocket No.: 24-3062PCT with its associated STAs. In example 1600, frame exchange 1614 may extend to the end of TXOP duration 1612.

[0152] In an embodiment, on receiving frame 1610 via the PCH, AP 1604 may determine that frame 1610 is carried in an inter-BSS PPDU (OBSS PPDU). As discussed above in relation to FIG. 11 and in accordance with NPCA operation, AP 1604 may set a NAV 1616 for the PCH based on TXOP duration 1612 and may switch to the NPCA PCH based on the determining that the PPDU being received via the PCH comprises an inter-BSS PPDU. In example 1600, AP 1604 may switch to the NPCA PCH at time T1 . In an embodiment, AP 1604 may be configured to switch back to the PCH based on TXOP duration 1612 (OBSS NAV duration for AP 1604), e.g., at time T2. In an embodiment, AP 1604 may switch to the PCH by / before an end of TXOP duration 1612. In an embodiment, AP 1604 may switch to the PCH before the end of TXOP duration 1612, e.g., before the end of TXOP duration 1612 by an NPCA switch back delay field value (e.g., indicated in an NPCA Operation Information / Parameters field of AP 1604).

[0153] In an embodiment, at the time of switching from the PCH to the NPCA PCH, AP 1604 may have buffered data for transmission. For example, while AP 1604 is receiving frame 1610, new data may arrive at AP 1604 for transmission to STA 1606 and / or STA 1608. In another embodiment (not shown in FIG. 16), the new data may arrive at AP 1604 for transmission to STA 1606 and / or STA 1608 before receiving frame 1610 on the PCH, but AP 1604 may not have gained control of the PCH for the transmission of the new data. In an embodiment, the new data may comprise data of a first category. In an embodiment, the data of the first category may comprise one or more data frames. In an embodiment, the one or more data frames are addressed / transmitted to one or more stations (STAs).

[0154] In an embodiment, the data of the first category may comprise data associated with low latency traffic. In an embodiment, the data associated with low latency traffic may comprise data associated with one or more of: a voice type access category (AC_VO) and a video type access category (AC_VI). In another embodiment, the data associated with low latency traffic may comprise data associated with one or more traffic identifiers (TIDs) with values equal to 4, 5, 6, or 7.

[0155] In another embodiment, the data of the first category may not be data associated with low latency traffic only. In an embodiment, the data of the first category may comprise data associated with one or more of: a voice type access category (AC_VO), a video type access category (AC_VI), a best effort type access category (AC_BE), and a background type access category (AC_BK). In an embodiment, the data of the first category may comprise data associated with one or more traffic identifiers (TIDs) with values equal to 0, 1 , 2, 3, 4, 5, 6, or 7.

[0156] In an embodiment, AP 1604 may determine a first duration, where the first duration is a duration required to transmit the data of the first category buffered at the AP. In an embodiment, where AP 1604 has data buffered for transmission at the time of switching to the NPCA PCH, AP 1604 may determine the first duration at the time of switching to the NPCA PCH.Docket No.: 24-3062PCT

[0157] In an embodiment, AP 1604 may be configured to switch to the PCH by / at the end of TXOP duration 1612 (e.g at time T2), if the first duration is less than a value based on TXOP duration 1612 indicated in frame 1610 comprised in the PPDU received via the PCH. In an embodiment, the value based on TXOP duration 1612 may be the same as TXOP duration 1612 (or a remaining duration of TXOP duration 1612). As such, AP 1604 may transmit the data to STA 1606 and / or STA 1608 via the NPCA PCH before switching to the PCH at time T2. On the other hand, if the first duration exceeds / is greater than the value based on TXOP duration 1612, AP 1604 may be configured to determine a first time in order to switch from the NPCA PCH to the PCH at the first time. In an embodiment, when AP 1604 has buffered data for transmission at the time of switching to the NPCA PCH, AP 1604 may determine the first time at the time of switching to the NPCA PCH.

[0158] In example 1600, the first duration exceeds / is greater than the value based on TXOP duration 1612. As such, based on determining that the first duration exceeds / is greater than the value, AP 1604 determines the first time in order to switch from the NPCA PCH to the PCH at the first time. In an embodiment, determining the first time comprises determining the first time at the time of switching from the PCH to the NPCA PCH. In another embodiment, determining the first time comprises determining the first time a short inter-frame space (SIFS) after switching from the PCH to the NPCA PCH. In an embodiment, determining the first time is before an end of the TXOP duration 1612. In an embodiment, the first time is based on the first duration. In an embodiment, the first duration may comprise a transmission duration of the data via one or more data frames, a duration of one or more short interframe spacings (SIFSs), and a transmission duration of one or more response frames in response to the data. In example 1600, the first duration may comprise the duration of a frame 1626, a frame 1628, a frame 1630, a frame 1632, a duration of SIFS before the transmission of each of frame 1626, 1628, 1630, and 1632, and a duration of an ICF-ICR exchange between AP 1604 and STA 1606 and / or STA 1608 as further described below. In an embodiment, frame 1626 and frame 1630 may comprise the data of the first category addressed to STA 1606 and STA 1608, respectively. In an embodiment, frame 1628 and frame 1632 may comprise response frames to frame 1626 and frame 1630, respectively. In example 1600, AP 1604 may calculate the first time considering the first duration and a duration for the transmission of a frame 1624 for announcing the first time. In an embodiment, AP 1604 sets / initializes / starts a first timer for switching from the NPCA PCH to the PCH based on the first time. In an embodiment, the first time may be a time T3 as illustrated in FIG. 16. After switching to the NPCA PCH and before the expiry of the first timer (e.g., before time T3), AP 1604 may be involved in uplink and / or downlink communications with its associated STAs on the NPCA PCH. In another embodiment (not shown in FIG. 16), AP 1604 may set / initialize / start (e.g., at T1) a first timer for switching from the NPCA PCH to the PCH based on TXOP duration 1612 and the NPCA switch back delay value of AP 1604. In an embodiment, AP 1604 may transmit via the NPCA PCH one or more frames to one or more STAs associated with AP 1604 (e.g., STA 1606 and / or STA 1608) before expiration of the first timer.Docket No.: 24-3062PCT

[0159] In an embodiment, on receiving frame 1610 via the PCH, STA 1606 / 1608 may determine that frame 1610 is carried in an inter-BSS PPDU (OBSS PPDU). Based on supporting / enabling NPCA operation, STA 1606 / 1608 may set a NAV 1618 / 1619 for the PCH based on TXOP duration 1612 and may switch to the NPCA PCH based on the determining that the PPDU being received via the PCH comprises an inter-BSS PPDU. In example 1600, STA 1606 / 1608 may switch to the NPCA PCH at time T1. In an embodiment, STA 1606 / 1608 may be configured to switch back to the PCH based on TXOP duration 1612 (OBSS NAV duration for STA 1606 / 1608). In an embodiment, STA 1606 / 1608 may switch to the PCH by / before an end of TXOP duration 1612. In an embodiment, STA 1606 / 1608 may switch to the PCH before the end of TXOP duration 1612, e.g., before the end of TXOP duration 1612 by an NPCA switch back delay field value (e.g., indicated in an NPCA Operation Information / Parameters field of AP 1604). In example 1600, STA 1606 / 1608 may be configured to switch to the PCH by / at the end of TXOP duration 1612 (e.g., at time T2). In an embodiment, STA 1606 / 1608 may set / initialize / start (e.g., at time T1) a second / third timer for switching from the NPCA PCH to the PCH based on TXOP duration 1612. In another embodiment, STA 1606 / 1608 may set / initialize / start (e.g., at T1) a second / third timer for switching from the NPCA PCH to the PCH based on TXOP duration 1612 and the NPCA switch back delay value of STA 1606 / 1608. After switching to the NPCA PCH and before the expiry of the second / third timer (e.g., before time T2), STA 1606 / 1608 may be involved in uplink and / or downlink communications with AP 1604 on the NPCA PCH.

[0160] In an embodiment, after switching to the NPCA PCH, AP 1604 may start a "MediumSyncDelay” timer for the medium synchronization duration of the NPCA PCH, and if the NPCA PCH is idle (at / after expiration of the MediumSyncDelay timer), AP 1604 may access the NPCA PCH to transmit a frame on the NPCA PCH. In example 1600, AP 1604 may transmit a frame 1620 to STA 1606. In another embodiment (not shown in FIG. 16), AP 1604 may transmit a frame 1620 to STA 1606 and / or STA 1608. In an embodiment, frame 1620 may comprise an initial control frame (IGF). In another embodiment, frame 1620 may comprise a trigger frame. In another embodiment, frame 1620 may comprise a request-to-send (RTS) frame. In response to frame 1620, STA 1606 may transmit a frame 1622 to STA 1606. In another embodiment (not shown in FIG. 16), if frame 1620 is addressed to STA 1608, STA 1608 may transmit a frame to AP 1604 in response to frame 1620. In an embodiment, where frame 1620 is an IGF, frame 1622 may comprise an initial control response frame (ICR). In another embodiment, where frame 1620 is a trigger frame, frame 1622 may comprise a clear-to-send (CTS) frame. In another embodiment, where frame 1620 is an RTS frame, frame 1622 may comprise a CTS frame In an embodiment, before transmitting the data of the first category, AP 1604 may be configured to transmit frame 1624 to announce the first time. This allows STAs associated with AP 1604 to determine the switching time from the NPCA PCH to the PCH. In an embodiment, on receiving frame 1622, AP 1604 may transmit frame 1624. In another embodiment (not shown in FIG. 16), AP 1604 may have set / initialized / started (e.g., at T1 ) the first timer for switching from the NPCA PCH to the PCH based on TXOP duration 1612 and the NPCA switch back delay value of AP 1604. As such, AP 1604 may transmitDocket No.: 24-3062PCT to STA 1606 and / or STA 1608 one or more frames comprising portions of frames 1626 and 1630 via the NPCA PCH before expiration of the first timer. AP 1604 then switches from the NPCA PCH to the PCH when the first timer expires. Similarly, STA 1606 and STA 1608 switch from the NPCA PCH to the PCH when the second timer and the third timer expire.

[0161] In an embodiment, frame 1624 comprises / indicates the first time. In an embodiment, the first time may be provided / comprised in a duration field of a PHY header of frame 1624. In an embodiment, frame 1624 may comprise a broadcast frame. In another embodiment, frame 1624 may comprise a unicast frame addressed to a STA. In example 1600, frame 1624 may comprise a broadcast frame. As such, all STAs associated with AP 1604 (not only the STAs that are recipients of the data of the first category, e.g., not only STA 1606 and STA 1608) may update their timers for switching from the NPCA PCH to the PCH based on frame 1624. In an embodiment, frame 1624 may further comprise an indication that frame 1624 comprises / indicates the first time. In an embodiment, the indication may be provided / comprised in the PHY header of frame 1624. In an embodiment, frame 1624 may further comprise a management frame, an action frame, a control frame, a quality of service (QoS) null frame, or a QoS data frame.

[0162] In another embodiment (not shown in FIG. 16), instead of transmitting frame 1624 comprising the first time, the first time may be included in frame 1620. In such an embodiment, frame 1620 may further include an indication that frame 1620 comprises / indicates the first time.

[0163] In an embodiment, on receiving frame 1624, STA 1606 / 1608 may decode the PHY header of frame 1624. In an embodiment, STA 1606 / 1608 may obtain the indication that frame 1624 comprises / indicates the first time. Based on obtaining the indication, STA 1606 / 1608 may locate the first time in frame 1624 and may update the second / third timer based on the first time (e.g., T3). Based on updating the second / third timer, STA 1606 / 1608 is / becomes configured to switch from the NPCA PCH to the PCH at the first time. In another embodiment, STA 1606 may obtain the first time provided in a duration field of the PHY header of frame 1624 and update the second / third timer based on the first time (e.g., T3) without obtaining the indication (e.g., frame 1624 may not comprise the indication). As such, STA 1606 / 1608 remains on the NPCA PCH, may or may not receive one or more frames from AP 1604 while remaining on the NPCA PCH until the second / third timer is expired, and switches to the PCH at time T3 instead of time T2.

[0164] In an embodiment, after transmitting frame 1624, AP 1604 may transmit to STA 1606 frame 1626 comprising the data of the first category. In response to frame 1626, AP 1604 may receive from STA 1606 frame 1628. After receiving frame 1628, AP 1604 may transmit to STA 1608 frame 1630 comprising the data of the first category. In response to frame 1630, AP 1604 may receive from STA 1608 frame 1632. In an embodiment, frame 1628 and frame 1632 may comprise BA frames. As illustrated in example 1600, AP 1604 transmits the data of the first category timely via the NPCA PCH. After determining the time required for transmission of the data of the first category to exceed TXOP duration 1612, AP 1604 switches from theDocket No.: 24-3062PCTNPCA PCH to the PCH at the first time, where the first time is based on the time required for transmission of the data and is after TXOP duration 1612. As such, potential delay or discarding of the data may be avoided.

[0165] FIG. 17 shows an example 1700 that illustrates an example NPCA operation according to an embodiment. As shown in FIG. 17, example 1700 includes a STA 1702, an AP 1704, a STA 1706 and a STA 1708. AP 1704, STA 1706, and STA 1708 may belong to the same BSS. STA 1702 may belong to a different BSS than AP 1704, STA 1706, and STA 1708. In an embodiment, STA 1702 may be an AP STA or a non- AP STA. In an embodiment, AP 1704 may be an AP STA, and STAs 1706 and 1708 may be non-AP STAs. In an embodiment, where AP 1704 is an AP STA and STAs 1706 and 1708 are non-AP STAs, STAs 1706 and 1708 may be associated with AP 1704. In an embodiment, AP 1704, STA 1706, and STA 1708 may 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) (SCH2 is not shown in FIG. 17 for simplification purposes).

[0166] As shown in FIG. 17, example 1700 may begin with STA 1702 transmitting a frame 1710 on the PCH. As explained in detail with reference to example 1600, STA 1702 may obtain a TXOP on the PCH for a TXOP duration 1712 and may perform uplink and / or downlink communications as illustrated with a frame exchange 1714 within TXOP duration 1712.

[0167] As explained in detail with reference to example 1600, AP 1704 may receive new data comprising data of a first category for transmission to STA 1706 and / or STA 1708, while receiving frame 1710 on the PCH. On receiving frame 1710 via the PCH, AP 1704 may determine that frame 1710 is carried in an inter- BSS PPDU (OBSS PPDU) and may switch to the NPCA PCH at time T1 after setting a NAV 1716 for TXOP duration 1712. Based on the determining that a duration required to transmit the data of the first category exceeds TXOP duration 1712, AP 1704 sets / initializes / starts a first timer for switching from the NPCA PCH to the PCH based on a first time (e.g., AP 1704 switches at time T3 instead of time T2). Here, the first time (e.g . , time T3) is determined considering the duration required to transmit the data of the first category on the NPCA PCH.

[0168] Similarly, on receiving frame 1710 via the PCH, STA 1706 and STA 1708 may determine that frame 1710 is carried in an inter-BSS PPDU (OBSS PPDU) and may switch to the NPCA PCH at time T1 after setting a NAV 1718 and a NAV 1719, respectively, for TXOP duration 1712. On the other hand, STA 1706 and STA 1708 may be configured to set / initialize / start a second timer and a third timer, respectively, for switching from the NPCA PCH to the PCH based on TXOP duration 1712. STA 1706 and STA 1708 may set the second timer and the third timer to time T2.

[0169] As explained in detail with reference to example 1600, after switching to the NPCA PCH and gaining control of the NPCA PCH, AP 1704 announces to STA 1706 and STA 1708 via a frame 1724 the first time for switching to the NPCA PCH, e.g., after transmitting a frame 1720 and receiving a frame 1722. In an embodiment, transmitting frame 1720 and receiving frame 1722 may be an example of an ICF-ICR exchange.Docket No.: 24-3062PCTSTA 1706 and STA 1708 update the second timer and the third timer based on the first time. AP 1704 then transmits a frame 1726 and a frame 1730, respectively, to STA 1706 and STA 1708, where frame 1726 and frame 1730 comprise the data of the first category. AP 1704 then receives a frame 1728 and a frame 1732 in response to frame 1726 and frame 1730, before the first time. AP 1704, STA 1706, STA 1708 then switch from the NPCA PCH to the PCH at the first time (e.g., time T3).

[0170] After switching from the NPCA PCH to the PCH, AP 1704, STA 1706, and / or STA 1708 may contend, at a second time (e.g., time T4), for the PCH. In an embodiment, the second time may be based on, accounts for, or comprises a medium synchronization delay / threshold of the PCH. In an embodiment, the second time may be based on, accounts for, or comprises the medium synchronization delay / threshold of the PCH based on the first time being later than a third time. In an embodiment, the third time (e.g., time T5) may be based on TXOP duration 1712 and the medium synchronization delay / threshold. For example, the third time may be obtained by adding the medium synchronization delay / threshold of the PCH (illustrated by duration 1734) to the end of TXOP duration 1712. In other words, if AP 1704 switches back to the PCH at the first time (at time T3) after expiration of the medium synchronization delay timer (at time T5), AP 1704 initiates a medium synchronization delay timer before contending for the PCH. In example 1700, the first time (e.g., T3) is after the third time (T5), hence, AP 1704 may contend for the PCH at the second time (T4), which accounts for the medium synchronization delay / threshold of the PCH. In another embodiment (not shown in FIG. 17), the second time may not be based on, does not account for, does not comprise the medium synchronization delay / threshold based on the first time being earlier than or equal to the third time (time T5). Accordingly, if AP 1704 switches back to the PCH before the third time (time T5), AP 1704 may not perform medium synchronization before contending for the PCH.

[0171] In an embodiment, AP 1704 may consider the medium synchronization delay / threshold when determining the first time so that AP 1704 and / or its associated STAs may not have to perform medium synchronization on switching back to the PCH. In an embodiment (not shown in FIG. 17), AP 1704 may contend for the PCH at the second time (T4) after switching to the PCH at the first time (T3), where the first time and the second time are equal. In such a case, AP and / or its associated STAs may contend for the PCH at an earlier time compared to other STAs that may have to perform medium synchronization.

[0172] While switching back to the PCH at a time before / after the third time for medium synchronization necessity on the PCH is explained via example 1700, a person skilled in the art would appreciate that the embodiment of FIG. 17 may easily be extended to the embodiments of FIGs. 13, 14, 15 and 16, described above.

[0173] FIG. 18 illustrates an example process 1800 according to an embodiment. Example process 1800 is provided for the purpose of illustration only and is not limiting of embodiments. Example process 1800 may be performed by an access point (AP), such as AP 1304, AP 1404, AP 1504, AP 1604, or AP 1704, for example. As shown in FIG. 18, example process 1800 may include steps 1802, and 1804.Docket No.: 24-3062PCT

[0174] Step 1802 includes determining, by the AP, whether a first duration, required to transmit data of a first category, buffered at the AP, on a first channel, exceeds / is greater than a value based on a second duration indicated in a physical layer (PHY) protocol data unit (PPDU) received via a second channel.

[0175] Step 1804 includes switching, at a first time, from the first channel to the second channel, wherein the first time is based on the determining.

[0176] In an embodiment, process 1800 may further comprise determining, by the AP, that the PPDU being received via the second channel comprises an inter-basic service set (inter-BSS) PPDU. In an embodiment, process 1800 may further comprise switching, by the AP, from the second channel to the first channel, based on the determining that the PPDU being received via the second channel comprises an inter-BSS PPDU. In an embodiment, the switching from the second channel to the first channel occurs before the switching from the first channel to the second channel.

[0177] In an embodiment, the data of the first category comprises one or more data frames In an embodiment, the one or more data frames are addressed / transmitted to one or more stations (STAs).

[0178] In an embodiment, the data of the first category comprises data associated with low latency traffic. In an embodiment, the data associated with low latency traffic comprises data associated with one or more of: a voice type access category (AC_VO) and a video type access category (AC_VI). In another embodiment, the data associated with low latency traffic comprises data associated with one or more traffic identifiers (TIDs) with values equal to 4, 5, 6, or 7.

[0179] In an embodiment, the data of the first category comprises data associated with one or more of: a voice type access category (AC_VO), a video type access category (AC_VI), a best effort type access category (AC_BE), and a background type access category (AC_BK) In another embodiment, the data of the first category comprises data associated with one or more traffic identifiers (TIDs) with values equal to 0, 1 , 2, 3, 4, 5, 6, or 7.

[0180] In an embodiment, the second duration indicated in the PPDU comprises a value indicated in a duration field of a physical layer (PHY) header of the PPDU. In another embodiment, the second duration indicated in the PPDU comprises a value indicated in a duration field of a medium access control (MAC) header of the PPDU.

[0181] In an embodiment, process 1800 may further comprise determining, by the AP, the first time. In an embodiment, determining the first time comprises determining the first time a short inter-frame space (SIFS) after switching from the second channel to the first channel. In an embodiment, determining the first time comprises determining the first time before an end of the second duration. In an embodiment, process 1800 may further comprise setting / initializing / starting a timer for switching from the first channel to the second channel based on the first time.

[0182] In another embodiment, determining the first time comprises determining the first time after / based on arrival at the AP of the data of the first category. In an embodiment, process 1800 may further compriseDocket No.: 24-3062PCT setting / initializing / starting a timer for switching from the first channel to the second channel based on the second duration. In an embodiment, process 1800 may further comprise updating the timer based on the first time.

[0183] In an embodiment, the first time is based on the first duration. In an embodiment, the first duration comprises a transmission duration of the data via one or more data frames, a duration of one or more short interframe spacings (SIFSs), and a transmission duration of one or more response frames in response to the data.

[0184] In an embodiment, process 1800 may further comprise transmitting, by the AP, a first frame comprising / indicating the first time. In an embodiment, the first time is provided / comprised in a duration field of a physical layer (PHY) header of the first frame. In an embodiment, the first frame comprises a broadcast frame or a unicast frame addressed to a first station (STA). In an embodiment, the first frame further comprises an indication that the first frame comprises / indicates the first time In an embodiment, the indication is provided / comprised in the PHY header of the first frame.

[0185] In an embodiment, the first frame comprises a management frame, an action frame, a control frame, a quality of service (QoS) null frame, or a QoS data frame.

[0186] In an embodiment, the first frame further comprises the data of the first category. In an embodiment, the first frame comprises a QoS data frame.

[0187] In an embodiment, process 1800 may further comprise transmitting, by the AP, a second frame comprising the data of the first category. In an embodiment, the second frame is transmitted to a first STA. In an embodiment, process 1800 may further comprise receiving, by the AP from the first STA, a third frame in response to the second frame. In an embodiment, the third frame comprises a block acknowledgment (BA) frame.

[0188] In an embodiment, process 1800 may further comprise contending, by the AP at a second time, for the second channel, after switching from the first channel to the second channel. In an embodiment, the second time is not based on, does not account for, does not comprise a medium synchronization delay / threshold of the second channel based on the first time being earlier than or equal to a third time. In another embodiment, the second time is based on, accounts for, comprises the medium synchronization delay / threshold of the second channel based on the first time being later than the third time. In an embodiment, the third time is based on the second duration and the medium synchronization delay / threshold.

[0189] In an embodiment, the first channel comprises a non-primary channel access primary channel (NPCA PCH). In an embodiment, the second channel comprises a primary channel (PCH).

[0190] FIG. 19 illustrates an example process 1900 according to an embodiment. Example process 1900 is provided for the purpose of illustration only and is not limiting of embodiments. Example process 1900 may be performed by a station (STA), such as STA 1306, STA 1406, STA 1506, STA 1606, or STA 1706, for example. As shown in FIG. 19, example process 1900 may include steps 1902, and 1904.Docket No.: 24-3062PCT

[0191] Step 1902 includes receiving, by the STA from an access point (AP), a first time, determined by the AP based on a first duration, wherein the first duration is a duration required to transmit data of a first category, buffered at the AP, on a first channel, exceeding / being greater than a value based on a second duration indicated in a physical layer (PHY) protocol data unit (PPDU) received via a second channel.

[0192] Step 1904 includes switching, by the STA, at the first time, from the first channel to the second channel.

[0193] In an embodiment, process 1900 may further comprise determining, by the STA, that the PPDU being received via the second channel comprises an inter-basic service set (inter-BSS) PPDU. In an embodiment, process 1900 may further comprise switching, by the STA, from the second channel to the first channel, based on the determining that the PPDU being received via the second channel comprises an inter- BSS PPDU. In an embodiment, the switching from the second channel to the first channel occurs before the switching from the first channel to the second channel.

[0194] In an embodiment, the data of the first category comprises one or more data frames. In an embodiment, the one or more data frames are addressed / transmitted to one or more stations (STAs).

[0195] In an embodiment, the data of the first category comprises data associated with low latency traffic. In an embodiment, the data associated with low latency traffic comprises data associated with one or more of: a voice type access category (AC_VO) and a video type access category (AC_VI). In another embodiment, the data associated with low latency traffic comprises data associated with one or more traffic identifiers (TIDs) with values equal to 4, 5, 6, or 7.

[0196] In an embodiment, the data of the first category comprises data associated with one or more of: a voice type access category (AC_VO), a video type access category (AC_VI), a best effort type access category (AC_BE), and a background type access category (AC_BK). In another embodiment, the data of the first category comprises data associated with one or more traffic identifiers (TIDs) with values equal to 0, 1 , 2, 3, 4, 5, 6, or 7.

[0197] In an embodiment, the second duration indicated in the PPDU comprises a value indicated in a duration field of a physical layer (PHY) header of the PPDU. In another embodiment, the second duration indicated in the PPDU comprises a value indicated in a duration field of a medium access control (MAC) header of the PPDU.

[0198] In an embodiment, process 1900 may further comprise setting / initializing / starting, by the STA, a timer for switching from the first channel to the second channel based on the second duration. In an embodiment, process 1900 may further comprise updating the timer based on the first time.

[0199] In an embodiment, the first time is based on the first duration. In an embodiment, the first duration comprises a transmission duration of the data via one or more data frames, a duration of one or more short interframe spacings (SIFSs), and a transmission duration of one or more response frames in response to the data.Docket No.: 24-3062PCT

[0200] In an embodiment, process 1900 may further comprise receiving, by the STA, a first frame comprising / indicating the first time. In an embodiment, the first time is provided / comprised in a duration field of a physical layer (PHY) header of the first frame. In an embodiment, the first frame comprises a broadcast frame or a unicast frame addressed to the STA. In an embodiment, the first frame further comprises an indication that the first frame comprises / indicates the first time. In an embodiment, the indication is provided / comprised in the PHY header of the first frame.

[0201] In an embodiment, the first frame comprises a management frame, an action frame, a control frame, a quality of service (QoS) null frame, or a QoS data frame

[0202] In an embodiment, the first frame further comprises the data of the first category. In an embodiment, the first frame comprises a QoS data frame.

[0203] In an embodiment, process 1900 may further comprise receiving, by the STA from the AP, a second frame comprising the data of the first category. In an embodiment, process 1900 may further comprise transmitting, by the STA to the AP, a third frame in response to the second frame. In an embodiment, the third frame comprises a block acknowledgment (BA) frame.

[0204] In an embodiment, process 1900 may further comprise contending, by the STA at a second time, for the second channel, after switching from the first channel to the second channel. In an embodiment, the second time is not based on, does not account for, does not comprise a medium synchronization delay / threshold of the second channel based on the first time being earlier than or equal to a third time. In another embodiment, the second time is based on, accounts for, comprises the medium synchronization delay / threshold of the second channel based on the first time being later than the third time. In an embodiment, the third time is based on the second duration and the medium synchronization delay / threshold.

[0205] In an embodiment, the first channel comprises a non-primary channel access primary channel (NPCA PCH). In an embodiment, the second channel comprises a primary channel (PCH).

[0206] In an embodiment, a STA (e.g., an AP or non-AP STA) described in any of the embodiments above may further perform one or more of the NPCA operations described herein below. As would be understood by a person of skill in the art based on the teachings, any of the NPCA operations described below may be combined with the procedures / operations described above. For example, a STA (e.g., an AP or non-AP STA) described above in relation to FIGS. 11 -19 may switch to the NPCA primary channel for NPCA operation if either condition 1) or 2), described below, is met.

[0207] 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.Docket No.: 24-3062PCT

[0208] In an implementation, an NPCA AP that has an operating bandwidth less than 80 MHz does not enable NPCA operation. In an implementation, an AP of a multiple BSSID set that enables NPCA operation may indicate the same NPCA primary channel, same NPCA minimum duration, same NPCA switching delay, and same NPCA switch back delay as all of the other APs of the same multiple BSSID set that have enabled NPCA operation. In an implementation, an AP of a co-hosted BSS that enables NPCA operation may indicate the same NPCA primary channel, same NPCA minimum duration, same NPCA switching delay, and same NPCA switch back delay as all of the other APs of the same co-hosted BSSs that have enabled NPCA operation.

[0209] 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.

[0210] 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.

[0211] 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 .

[0212] 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 O.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.Docket No.: 24-3062PCTAn NPCA AP may indicate one or more 20 MHz subchannels as punctured in the NPCA Disabled Subchannel Bitmap field of the EHT Operation Element for the purpose of creating a gap between the PPDU that initiated the NPCA switch and the NPCA operating channel.If no NPCA Disabled Subchannel Bitmap field is present in the NPCA Operation Parameters field transmitted by the AP that the STA is associated with, then the subchannels may be punctured during NPCA operation.

[0213] 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.

[0214] In an implementation, a non-AP NPCA STA may indicate an NPCA switching delay and an NPCA switch back delay, respectively, in the NPCA Switching Delay field and NPCA Switch Back Delay fields of the CMP Request frames.

[0215] 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 CMP 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.

[0216] 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.

[0217] 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.

[0218] 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.Docket No.: 24-3062PCT

[0219] In an implementation, an NPCA STA may switch to the NPCA primary channel for NPCA operation if the NPCA mode has been enabled for the BSS of which it is a member and either condition 1 ) or 2) is met: 1 ) the STA received a PPDU and / or received a PHY-RXSTART indication primitive for an HE / EHT / UHR PPDU on the BSS primary channel and all of the following conditions are true: a) Condition 2) is not true. b) The PPDU is classified by the STA as in inter-BSS PPDU. c) At least one of the following conditions is true: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.: 24-3062PCT 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.

[0220] 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.

[0221] 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.

[0222] In an implementation, the MAC variable NPCA_PHY_TXOP_REM_DUR derived from a received PPDU is:Set to 0, if the RXVECTOR parameter TXOP_DURATION is UNSPECIFIED, or if the NPCA AP corresponding to the BSS of which the STA is a member has not enabled MOPLEN NPCA.Docket No.: 24-3062PCTOtherwise, 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.

[0223] 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.

[0224] In an implementation, when an NPCA STA switches to the NPCA primary channel for NPCA operation, then the following rules apply:1 ) If the STA switches from the BSS primary channel to the NPCA primary channel based on meeting condition 1 ) described above, the STA initiates the switch at the NPCA HE switch time and shall be ready to transmit and receive frames (subject to its capabilities and operating mode) on the NPCA primary channel no later than the value of its most recently indicated NPCA switching delay after the NPCA HE switch time. The NPCA HE switch time is the point in time immediately after the reception of the HE-SIG-A / U-SIG field of the received PPDU from condition 1) above.2) If the STA switches from the BSS primary channel to the NPCA primary channel based on meeting condition 2) described above, the STA initiates the switch at the NPCA NHT switch time and shall be ready to transmit and receive frames addressed to it (subject to its capabilities and operating mode) on the NPCA primary channel no later than the value of its most recently indicated NPCA switching delay after the NPCA NHT switch time. The NPCA NHT switch time is equal to the point in time that is 3 x TSYM after the reception of the L-SIG field of the third PPDU of the received sequence of PPDUs from condition 2) above.3) The STA uses the same EDCA parameter set and EPCS EDCA parameter set values for operation on the NPCA primary channel as it uses on the BSS primary channel.4) At each NPCA HE switch time or NPCA NHT switch time, as appropriate, if the STA is an AP or if the STA is a non-AP STA and transmission of frames that are not a response to a Trigger frame is notDocket No.: 24-3062PCT disabled by the MU EDCA protocol, the STA may initiate a TXOP on the NPCA primary channel with the following exceptions: а) 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 2lnit-QSRc_NPCAx(CWmin[AC] + 1 ) - 1 . v) invoke the backoff procedure even if the medium for the NPCA primary channel is not busy. vi) initiate countdown of the MAC variable NPCA_TIMER in units of 1 usee.5) A first STA does not initiate a transmission on the NPCA primary channel to a second STA until theNPCA switching delay time of the second STA has elapsed since the NPCA HE switch time at the first STA if the first STA is switching due to condition 1 ) above or since the NPCA NHT switch time at the first STA if the first STA is switching due to condition 2) above. б) 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.7) An NPCA AP that transmits a Trigger frame on the NPCA primary channel indicates RU index values that use the NPCA primary channel as the reference primary channel.8) An NPCA STA that transmits a Trigger frame on the NPCA primary channel sets the NPCA Primary Indication field to 1 in the Special User Info field, otherwise, this field is set to 0.Docket No.: 24-3062PCT9) The 20 MHz channels occupied by PPDUs transmitted by the STA shall meet all of the following conditions: a) include at least the NPCA primary channel. b) all be within the BSS bandwidth. c) not include any of the channels occupied by either the PPDU mentioned in condition 1) or by the third PPDU mentioned in condition 2), whichever caused the STA to switch from the BSS primary channel to the NPCA primary channel. d) not include channels that are indicated as punctured in the Disabled Subchannel Bitmap field in the EHT Operation element or in the NPCA Disabled Subchannel Bitmap field in the UHR Operation element.10) UHR ELR PPDUs, HE ER SU PPDUs, EHT MCS14 / 15 shall not be transmitted on the NPCA primary channel.1 1) Dynamic Subband Operation shall not be used on the NPCA primary channel.12) If TBTT for the BSS occurs while an NPCA AP is operating on the NPCA primary channel, the scheduling of the transmission of the Beacon frame and following group addressed frames shall be deferred until immediately after the AP switches back to the BSS primary channel.

[0225] 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.

[0226] 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.: 24-3062PCTCLAIMSWhat is claimed is:1 . A method, comprising: determining, by an access point (AP), that a physical layer (PHY) protocol data unit (PPDU) being received via a primary channel (PCH) comprises an inter-basic service set (inter-BSS) PPDU; switching, by the AP, from the PCH to a non-primary channel access primary channel (NPCA PCH), based on the determining; setting, by the AP, a timer for switching back from the NPCA PCH to the PCH based on a duration indicated in the PPDU and a switch back delay of the AP; before expiration of the timer, transmitting, by the AP and via the NPCA PCH, a frame to a station (STA) associated with the AP; and switching, by the AP and when the timer expires, from the NPCA PCH to the PCH.

2. A method, comprising: determining, by an access point (AP), whether a first duration, required to transmit data of a first category, buffered at the AP, on a first channel, exceeds / is greater than a value based on a second duration indicated in a physical layer (PHY) protocol data unit (PPDU) received via a second channel; and switching, at a first time, from the first channel to the second channel, wherein the first time is based on the determining.

3. The method of claim 2, further comprising determining, by the AP, that the PPDU being received via the second channel comprises an inter-basic service set (inter-BSS) PPDU.

4. The method of claim 3, further comprising switching, by the AP, from the second channel to the first channel, based on the determining that the PPDU being received via the second channel comprises an inter-BSS PPDU.

5. The method of claim 4, wherein the switching from the second channel to the first channel occurs before the switching from the first channel to the second channel.

6. The method of any of claims 2-5, wherein the data of the first category comprises one or more data frames.

7. The method of claim 6, wherein the one or more data frames are addressed / transmitted to one or more stations (STAs).

8. The method of any of claims 2-7, wherein the data of the first category comprises data associated with low latency traffic.

9. The method of claim 8, wherein the data associated with low latency traffic comprises data associated with one or more of: a voice type access category (AC_VO) and a video type access category (AC_VI).Docket No.: 24-3062PCT10. The method of claim 8, wherein the data associated with low latency traffic comprises data associated with one or more traffic identifiers (TIDs) with values equal to 4, 5, 6, or 7.11 . The method of any of claims 2-7, wherein the data of the first category comprises data associated with one or more of: a voice type access category (AC_VO), a video type access category (AC_VI), a best effort type access category (AC_BE), and a background type access category (AC_BK).

12. The method of any of claims 2-7, wherein the data of the first category comprises data associated with one or more traffic identifiers (TIDs) with values equal to 0, 1 , 2, 3, 4, 5, 6, or 7.

13. The method of any of claims 2-12, wherein the second duration indicated in the PPDU comprises a value indicated in a duration field of a physical layer (PHY) header of the PPDU.

14. The method of any of claims 2-12, wherein the second duration indicated in the PPDU comprises a value indicated in a duration field of a medium access control (MAC) header of the PPDU.

15. The method of any of claims 2-14, further comprising determining, by the AP, the first time.

16. The method of claim 15, wherein determining the first time comprises determining the first time a short inter-frame space (SIPS) after switching from the second channel to the first channel.

17. The method of any of claims 15-16, wherein determining the first time comprises determining the first time before an end of the second duration.

18. The method of any of claims 16-17, further comprising setting / initializing / starting a timer for switching from the first channel to the second channel based on the first time.

19. The method of claim 15, wherein determining the first time comprises determining the first time after / based on arrival at the AP of the data of the first category.

20. The method of claim 19, further comprising: setting / initializing / starting a timer for switching from the first channel to the second channel based on the second duration; and updating the timer based on the first time.21 . The method of any of claims 2-20, wherein the first time is based on the first duration.

22. The method of claim 21 , wherein the first duration comprises a transmission duration of the data via one or more data frames, a duration of one or more short interframe spacings (SIFSs), and a transmission duration of one or more response frames in response to the data.

23. The method of any of claims 2-22, further comprising transmitting, by the AP, a first frame comprising / indicating the first time.

24. The method of claim 23, wherein the first time is provided / comprised in a duration field of a physical layer (PHY) header of the first frame.

25. The method of any of claims 23-24, wherein the first frame comprises a broadcast frame or a unicast frame addressed to a first station (STA).Docket No.: 24-3062PCT26. The method of claim 25, wherein the first frame further comprises an indication that the first frame comprises / indicates the first time.

27. The method of claim 26, wherein the indication is provided / comprised in the PHY header of the first frame.

28. The method of any of claims 23-27, wherein the first frame comprises a management frame, an action frame, a control frame, a quality of service (QoS) null frame, or a QoS data frame.

29. The method of any of claims 23-27, wherein the first frame further comprises the data of the first category.

30. The method of claim 29, wherein the first frame comprises a QoS data frame.

31. The method of any of claims 23-28, further comprising transmitting, by the AP, a second frame comprising the data of the first category.

32. The method of claim 31 , wherein the second frame is transmitted to a first STA, further comprising receiving, by the AP from the first STA, a third frame in response to the second frame.

33. The method of claim 32, wherein the third frame comprises a block acknowledgment (BA) frame.

34. The method of any of claims 2-33, further comprising contending, by the AP at a second time, for the second channel, after switching from the first channel to the second channel.

35. The method of claim 34, wherein the second time is not based on, does not account for, does not comprise a medium synchronization delay / threshold of the second channel based on the first time being earlier than or equal to a third time.

36. The method of claim 35, wherein the second time is based on, accounts for, comprises the medium synchronization delay / threshold of the second channel based on the first time being later than the third time.

37. The method of any of claims 35-36, wherein the third time is based on the second duration and the medium synchronization delay / threshold.

38. The method of any of claims 2-37, wherein the first channel comprises a non-primary channel access primary channel (NPCA PCH).

39. The method of any of claims 2-38, wherein the second channel comprises a primary channel (PCH).

40. A method, comprising: determining, by a station (STA), that a physical layer (PHY) protocol data unit (PPDU) being received via a primary channel (PCH) comprises an inter-basic service set (inter-BSS) PPDU; switching, by the STA, from the PCH to a non-primary channel access primary channel (NPCA PCH), based on the determining; receiving, by the STA from an access point (AP), a first time, determined by the AP based on a first duration, wherein the first duration is a duration required to transmit data of a first category, bufferedDocket No.: 24-3062PCT at the AP, on the NPCA PCH, exceeding / being greater than a value based on a second duration indicated in the PPDU; and switching, by the STA, at the first time, from the NPCA PCH to the PCH.41 . A method, comprising: receiving, by a station (STA) from an access point (AP), a first time, determined by the AP based on a first duration, wherein the first duration is a duration required to transmit data of a first category, buffered at the AP, on a first channel, exceeding / being greater than a value based on a second duration indicated in a physical layer (PHY) protocol data unit (PPDU) received via a second channel; and switching, by the STA, at the first time, from the first channel to the second channel.

42. The method of claim 41 , further comprising determining, by the STA, that the PPDU being received via the second channel comprises an inter-basic service set (inter-BSS) PPDU.

43. The method of claim 42, further comprising switching, by the STA, from the second channel to the first channel, based on the determining that the PPDU being received via the second channel comprises an inter-BSS PPDU.

44. The method of claim 43, wherein the switching from the second channel to the first channel occurs before the switching from the first channel to the second channel.

45. The method of any of claims 41 -44, wherein the data of the first category comprises one or more data frames.

46. The method of claim 45, wherein the one or more data frames are addressed / transmitted to one or more stations (STAs).

47. The method of any of claims 41-46, wherein the data of the first category comprises data associated with low latency traffic.

48. The method of claim 47, wherein the data associated with low latency traffic comprises data associated with one or more of: a voice type access category (AC_VO) and a video type access category (AC_VI).

49. The method of claim 47, wherein the data associated with low latency traffic comprises data associated with one or more traffic identifiers (TIDs) with values equal to 4, 5, 6, or 7.

50. The method of any of claims 41-46, wherein the data of the first category comprises data associated with one or more of: a voice type access category (AC_VO), a video type access category (AC_VI), a best effort type access category (AC_BE), and a background type access category (AC_BK).51 . The method of any of claims 41-46, wherein the data of the first category comprises data associated with one or more traffic identifiers (TIDs) with values equal to 0, 1 , 2, 3, 4, 5, 6, or 7.

52. The method of any of claims 41-51 , wherein the second duration indicated in the PPDU comprises a value indicated in a duration field of a physical layer (PHY) header of the PPDU.

53. The method of any of claims 41-51 , wherein the second duration indicated in the PPDU comprises a value indicated in a duration field of a medium access control (MAC) header of the PPDU.Docket No.: 24-3062PCT54. The method of any of claims 41-53, further comprising setting / initializing / starting, by the STA, a timer for switching from the first channel to the second channel based on the second duration.

55. The method of claim 54, further comprising updating the timer based on the first time.

56. The method of any of claims 41 -55, wherein the first time is based on the first duration.

57. The method of claim 56, wherein the first duration comprises a transmission duration of the data via one or more data frames, a duration of one or more short interframe spacings (SIFSs), and a transmission duration of one or more response frames in response to the data.

58. The method of any of claims 41 -57, further comprising receiving, by the STA, a first frame comprising / indicating the first time.

59. The method of claim 58, wherein the first time is provided / comprised in a duration field of a physical layer (PHY) header of the first frame.

60. The method of any of claims 58-59, wherein the first frame comprises a broadcast frame or a unicast frame addressed to the STA.61 . The method of claim 60, wherein the first frame further comprises an indication that the first frame comprises / indicates the first time.

62. The method of claim 61 , wherein the indication is provided / comprised in the PHY header of the first frame.

63. The method of any of claims 58-62, wherein the first frame comprises a management frame, an action frame, a control frame, a quality of service (QoS) null frame, or a QoS data frame.

64. The method of any of claims 58-62, wherein the first frame further comprises the data of the first category.

65. The method of claim 64, wherein the first frame comprises a QoS data frame.

66. The method of any of claims 58-63, further comprising receiving, by the STA from the AP, a second frame comprising the data of the first category.

67. The method of claim 66, further comprising transmitting, by the STA to the AP, a third frame in response to the second frame.

68. The method of claim 67, wherein the third frame comprises a block acknowledgment (BA) frame.

69. The method of any of claims 41-68, further comprising contending, by the STA at a second time, for the second channel, after switching from the first channel to the second channel.

70. The method of claim 69, wherein the second time is not based on, does not account for, does not comprise a medium synchronization delay / threshold of the second channel based on the first time being earlier than or equal to a third time.71 . The method of claim 70, wherein the second time is based on, accounts for, comprises the medium synchronization delay / threshold of the second channel based on the first time being later than the third time.Docket No.: 24-3062PCT72. The method of any of claims 70-71 , wherein the third time is based on the second duration and the medium synchronization delay / threshold.

73. The method of any of claims 41 -72, wherein the first channel comprises a non-primary channel access primary channel (NPCA PCH).

74. The method of any of claims 41 -73, wherein the second channel comprises a primary channel (PCH).

75. 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 1-74.

76. 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- 74.

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