Coordinated non-primary channel access operation

Abstract

A first access point (AP) transmits to a second AP a first frame comprising a request to form a multi-AP group and receives from the second AP a second frame indicating acceptance of the request. The first AP transmits to the second AP a third frame indicating a non-primary channel access (NPCA) operation schedule for the second AP, where the NPCA operation schedule indicates a first time period during which the second AP enables NPCA operation and a second time period during which the second AP disables NPCA operation. The first AP receives from the second AP a fourth frame indicating acceptance or rejection of the NPCA operation schedule.

Description

Docket No.: 25-3004PCTTITLE COORDINATED NON-PRIMARY CHANNEL ACCESS OPERATIONCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application No. 63 / 754,642, filed February 6, 2025, 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 shows an example that illustrates another NPCA operation.

[0015] FIG. 13 illustrates an example multi-AP network.

[0016] FIG. 14 illustrates an example of a multi-AP negotiation procedure.

[0017] FIG. 15 shows an example that illustrates a problem that may arise with the use of multi-AP NPCA negotiation described in FIG. 14.

[0018] FIG. 16 shows an example of a procedure according to an embodiment.

[0019] FIG. 17 shows an example of another procedure according to an embodiment.

[0020] FIG. 18 shows an example of a further procedure according to an embodiment.

[0021] FIG. 19 shows an example of a further procedure according to an embodiment.

[0022] FIG. 20 illustrates an example process according to an embodiment.

[0023] FIG. 21 illustrates an example process according to an embodiment.Docket No.: 25-3004PCTDETAILED DESCRIPTION

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

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

[0026] In this disclosure, "a” and "an” and similar phrases are to be interpreted as "at least one” and "one or more.” Similarly, any term that ends with the suffix “(s)” is to be interpreted as "at least one” and “one or more.” In this disclosure, the term “may” is to be interpreted as “may, for example.” In other words, the term “may” is indicative that the phrase following the term “may” is an example of one of a multitude of suitable possibilities that may, or may not, be employed by one or more of the various embodiments. The terms “comprises” and “consists of’, as used herein, enumerate one or more components of the element being described. The term “comprises” is interchangeable with “includes” and does not exclude unenumerated components from being included in the element being described. By contrast, “consists of’ provides a complete enumeration of the one or more components of the element being described. The term “based on”, as used herein, may be interpreted as “based at least in part on” rather than, for example, “based solely on”. The term “and / or” as used herein represents any possible combination of enumerated elements. For example, “A, B, and / or C” may represent A; B; C; A and B; A and C; B and C; or A, B, and C.

[0027] If A and B are sets and every element of A is an element of B, A is called a subset of B. In this specification, only non-empty sets and subsets are considered. For example, possible subsets of B = {STA1 , STA2] are: {STA1}, {STA2}, and {STA1 , STA2}. The phrase “based on” (or equally “based at least on”) isDocket No.: 25-3004PCTindicative that the phrase following the term “based on” is an example of one of a multitude of suitable possibilities that may, or may not, be employed to one or more of the various embodiments. The phrase “in response to” (or equally “in response at least to”) is indicative that the phrase following the phrase “in response to” is an example of one of a multitude of suitable possibilities that may, or may not, be employed to one or more of the various embodiments. The phrase “depending on” (or equally “depending at least to”) is indicative that the phrase following the phrase “depending on" is an example of one of a multitude of suitable possibilities that may, or may not, be employed to one or more of the various embodiments. The phrase “employing / using” (or equally “employing / using at least”) is indicative that the phrase following the phrase “employing / using” is an example of one of a multitude of suitable possibilities that may, or may not, be employed to one or more of the various embodiments.

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

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

[0030] Many features presented are described as being optional through the use of “may” or the use of parentheses. For the sake of brevity and legibility, the present disclosure does not explicitly recite each and every permutation that may be obtained by choosing from the set of optional features. The present disclosure is to be interpreted as explicitly disclosing all such permutations. For example, a system described as having three optional features may be embodied in seven ways, namely with just one of the three possible features, with any two of the three possible features or with three of the three possible features.

[0031] Many of the elements described in the disclosed embodiments may be implemented as modules. A module is defined here as an element that performs a defined function and has a defined interface to other elements. The modules described in this disclosure may be implemented in hardware, software in combination with hardware, firmware, wetware (e.g., hardware with a biological element) or a combinationDocket No.: 25-3004PCTthereof, which may be behaviorally equivalent. For example, modules may be implemented as a software routine written in a computer language configured to be executed by a hardware machine (such as C, C++, Fortran, Java, Basic, Matlab or the like) or a modeling / simulation program such as Simulink, Stateflow, GNU Octave, or LabVIEWMathScript. It may be possible to implement modules using physical hardware that incorporates discrete or programmable analog, digital and / or quantum hardware. Examples of programmable hardware comprise: computers, microcontrollers, microprocessors, application-specific integrated circuits (ASICs); field programmable gate arrays (FPGAs); and complex programmable logic devices (CPLDs). Computers, microcontrollers, and microprocessors are programmed using languages such as assembly, C, C++, or the like. FPGAs, ASICs and CPLDs are often programmed using hardware description languages (HDL) such as VHSIC hardware description language (VHDL) or Verilog that configure connections between internal hardware modules with lesser functionality on a programmable device. The mentioned technologies are often used in combination to achieve the result of a functional module.

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

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

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

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

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

[0037] The example wireless communication networks illustrated in FIG. 1 may further include one or more ad-hoc networks or independent BSSs (IBSSs). An ad-hoc network or IBSS is a network that includes 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).

[0038] For example, in FIG. 1, STAs 106-4, 106-5, and 106-6 may be configured to form a first IBSS 112-1. Similarly, STAs 106-7 and 106-8 may be configured to form a second IBSS 112-2. Since an IBSS doesDocket No.: 25-3004PCTnot include an AP, it does not include a centralized management entity. Rather, STAs within an IBSS are managed in a distributed manner. STAs forming an IBSS may be fixed or mobile.

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

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

[0041] A frequency band may include one or more sub-bands or frequency channels For example, PPDUs conforming to the IEEE 802.11n, 802.11ac, 802.11ax and / or 802.11be standard amendments may be transmitted over the 2.4 GHz, 5 GHz, and / or 6 GHz bands, each of which may be divided into multiple 20 MHz channels. The PPDUs may be transmitted over a physical channel having a minimum bandwidth of 20 MHz. Larger channels may be optionally formed through channel bonding of a primary 20 MHz channel and one or more 20 MHz secondary channels. For example, PPDUs may be transmitted over physical channels having bandwidths of 40 MHz, 80 MHz, 160 MHz, or 320 MHz by bonding together a primary 20 MHz channel and 1 , 3, 7, or 15 secondary channel respectively. The primary channel is a common channel operation for all STAs where management frames are sent by the AP to ensure that all STAs (regardless of channel bonding support) can receive.

[0042] FIG. 2 is a block diagram illustrating example implementations of a STA 210 and an AP 260. As shown in FIG. 2, STA 210 may include at least one processor 220, a memory 230, and at least one transceiver 240. AP 260 may include at least one processor 270, a memory 280, and at least one transceiver 290. Processor 220 / 270 may be operatively connected to memory 230 / 280 and / or to transceiver 240 / 290.Docket No.: 25-3004PCT

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

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

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

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

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

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

[0049] The frame control field includes the following subfields: protocol version, type, subtype, “To DS’’, “From DS”, “More Fragments”, retry, power management, “More Data , protected frame, and +HTC.

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

[0051] The type and subtype subfields together identify the function of the MAC frame. There are three frame types: control, data, and management. Each of the frame types has several defined subtypes. BitsDocket No.: 25-3004PCTwithin the subtype subfield are used to indicate a specific modification of the basic data frame (subtype 0). For example, in data frames, the most significant bit (MSB) of the subtype subfield, bit 7 (B7) of the frame control field, is defined as the QoS subfield. When the QoS subfield is set to 1 , it indicates a QoS data frame, which is a data frame that contains a QoS control field in its MAC header. The second MSB of the subtype field, bit 6 (B6) of the frame control field, when set to 1 in data subtypes, indicates a data frame that contain no frame body field.

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

[0053] The “More Fragments” subfield is set to 1 in all data or management frames that have another fragment to follow the MAC service data unit (MSDU) or MAC management protocol data unit (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.

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

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

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

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

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

[0059] The duration / ID field of the MAC header indicates various contents depending on the frame type and subtype and the QoS capabilities of the sending STA. For example, in control frames of the power save poll (PS-Poll) subtype, the duration / ID field carries an association identifier (AID) of the STA that transmitted the frame in the 14 least significant bits (LSB), with the 2 most significant bits (MSB) set to 1 . In other frames sent by STAs, the duration / ID field contains a duration value (in microseconds) which is used by a recipient to update a network allocation vector (NAV). The NAV is a counter that indicates to a STA an amount of time during which the STA must defer from accessing the shared medium.

[0060] Up to four address fields may be present in the MAC frame format. The address fields are used to indicate the basic service set identifier (BSSID), source address (SA), destination address (DA), transmitting address (TA), and receiving address (RA). Certain frames may not contain some of the address fields. Certain address field usage may be specified by the relative position ofthe address field (1-4) within the MAC header,Docket No.: 25-3004PCTindependent of the type of address present in that field. Specifically, the address 1 field always identifies the intended receiver(s) of the frame, and the address 2 field, where present, always identifies the transmitter of the frame.

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

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

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

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

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

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

[0067] As shown in FIG. 4, trigger frame 400 includes a Frame Control field, a Duration field, a receiver address (RA) field, a transmitter address (TA) field, a Common Info field, a User List Info field, a Padding field, and an FCS field.

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

[0069] The Duration field indicates various contents depending on frame type and subtype and the QoS capabilities of the sending STA. For example, in control frames of the power save poll (PS-Poll) subtype, theDocket No.: 25-3004PCTDuration field carries an association identifier (AID) of the STA that transmitted the frame in the 14 least significant bits (LSB), and the 2 most significant bits (MSB) are both set to 1. In other frames sent by STAs, the Duration field contains a duration value (in microseconds) which is used by a recipient to update a network allocation vector (NAV).

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

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

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

[0073] The Padding field is optionally present in trigger frame 400 to extend the frame length to give recipient STAs enough time to prepare a response for transmission one 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 1s.

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

[0075] FIG.5 illustrates an example multi-user request to send (MU-RTS) trigger frame 500. MU-RTS trigger frame 500 may be used by an AP to solicit simultaneous CTS frames from multiple STAs to transmit a downlink (DL) MU PPDU to the multiple STAs. As shown in FIG. 5, MU-RTS trigger frame 500 may comprise a frame control field, a duration field, an RA field, a TA field, a common info field, one or more user info fields, a padding field, and an FCS field. The frame control, TA, RA, padding, and FCS fields may be similar to 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.: 25-3004PCT

[0076] 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.

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

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

[0079] In an example, STA 702 may transmit an RTS frame 706 to STA 704. STA 702 may transmit RTS frame 706 to protect from hidden STA(s) the transmission of a data frame 710 that STA 702 intends to transmit. RTS frame 706 may include a Duration / 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.

[0080] In an example, STA 704 may respond to RTS frame 706 by transmitting a CTS frame 708 to STA 702. CTS frame 708 may be transmitted one SIFS period after RTS frame 706. STA 704 may respond toDocket No.: 25-3004PCTRTS frame 706 when RTS frame 706 is addressed to STA 704 and after considering the NAV, unless the NAV was set by a frame originating from STA 702. STA 704 may respond to the RTS frame 706 when RTS frame 706 is addressed to STA 704 and if the NAV indicates idle. For a non-S1G STA, the NAV indicates idle when the NAV count is 0 or when the NAV count is non-zero but a nonbandwidth signaling TA obtained from a TA field of RTS frame 706 matches a saved TXOP holder address. For an S1G 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.

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

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

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

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

[0085] In example 800, AP 802 wishes to transmit a downlink (DL) multi-user (MU) PPDU 814 to STAs 804 and 806. DL MU PPDU 814 may comprise data for each of STAs 804 and 806. DL MU PPDU 814 may occupy a plurality of channels (e.g., 20 MHz channels). Each channel of the plurality of channels may carry the data for a respective STA (e.g., STA 804, STA 806) served by DL MU PPDU 814.

[0086] As shown in FIG. 8, to protect the transmission of DL MU PPDU 814 to STAs 804 and 806 from interference by OBSS STAs hidden from AP 802, AP 802 may use the MU-RTS / CTS procedure to initiate a TXOP and to protect the TXOP frame exchange sequence. AP 802 may initiate the TXOP by transmitting an MU-RTS trigger frame 808 that solicits simultaneous CTS frame transmissions from STAs 804 and 806.Docket No.: 25-3004PCT

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

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

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

[0090] After transmitting MU-RTS trigger frame 808, AP 802 may wait for a CTSTimeout interval of aSIFSTime + aSlotTime + aRxPHYStartDelay that begins when a MAC layer of AP 802 receives a PHYTXEND confirm primitive for transmitted MU-RTS trigger frame 808 If the MAC layer does not receive a PHY-RXEARLYSIG. indication or a PHY-RXSTART. indication primitive during the CTSTimeout interval, AP 802 may conclude that the transmission of MU-RTS trigger frame 808 has failed, and, if MU-RTS trigger frame 808 initiated a TXOP, AP 802 may invoke its backoff procedure. If the MAC layer receives a PHY-RXEARLYSIG. indication or a PHY-RXSTART. indication primitive during the CTSTimeout interval, then the MAC layer may wait for the corresponding PHY-RXEND. indication primitive to determine whether transmission of MU-RTS trigger frame 808 was successful. The receipt of a CTS frame from any non-AP STA addressed by MU-RTS trigger frame 808 before the PHY-RXEND. indication primitive shall be interpreted as the successful transmission of MU-RTS trigger frame 808, permitting the frame exchange sequence to continue. The receipt of any other type of frame shall be interpreted as a failure of the transmission of MU-RTS trigger frame 808. AP 802 may process the received frame and, if MU-RTS trigger frame 808 initiated a TXOP, AP 802 shall invoke its backoff procedure at the PHY-RXEND. indication primitive.

[0091] In example 800, on receiving MU-RTS trigger frame 808, STAs 804 and 806 respond by transmitting respectively CTS frames 810 and 812 to AP 802. In an example, STAs 804 and 806 begin the transmissionDocket No.: 25-3004PCTof 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 802.11 standard (“IEEE P802.11-REVme™ / D3.0, April 2023”). Otherwise, if one of the conditions is not met, STA 804 (or STA 806) does not send a CTS frame to AP 802.

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

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

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

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

[0096] It is envisioned in future IEEE 802.11 standards that a STA (AP STA or non-AP STA) may access a non-primary channel to communicate with another STA. Such operation may be referred to as non-primary channel access (NPCA) operation. Specifically, in addition to a default primary channel (which is used by all STAs in the BSS and via which the AP transmits management frames), the STA may have a channel considered as an NPCA primary channel. The NPCA primary channel may be a secondary channel of the BSS. The STA may transmit or receive on a channel that includes an NPCA primary channel but that does not necessarily include the primary channel (e.g., when the primary channel is unavailable). The STA may maintain a NAV for an NPCA primary channel independent of the NAV associated with the primary channel.Docket No.: 25-3004PCT

[0097] A STA (AP STA or non-AP STA) that supports NPCA operation may be called an NPCA STA. An AP (AP STA) that supports NPCA operation may be called an NPCA AP. A non-AP STA that supports NPCA operation may be called a non-AP NPCA STA.

[0098] FIG. 9 shows an example that illustrates NPCA operation. For the purpose of illustration, NPCA operation is contrasted with single primary channel (non-NPCA) operation. As shown in FIG. 9, a 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 .

[0099] As shown in FIG. 9, in non-NPCA operation, when the STA has a non-zero NAV for the PCH, the STA may not communicate via any channel of the BSS. The non-zero NAV for the PCH may be due to the STA receiving / detecting an inter-BSS PPDU on the PCH. Instead, the STA waits for the NAV for the PCH to reach zero before contending for the PCH to transmit via the PCH. 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).

[0100] In NPCA operation, the STA may switch to the NPCA PCH when the STA detects / receives an inter-BSS PPDU on the PCH. The STA may set a NAV for the PCH based on the inter-BSS PPDU (e.g., based on a duration field a frame carried in the inter-BSS PPDU, a transmission opportunity (TXOP) duration field of the inter-BSS PPDU, or a length field of the inter-BSS PPDU) and may switch to the NPCA PCH for a duration based on the NAV set for the PCH. After switching to the NPCA PCH, the STA may communicate via the NPCA PCH or a channel comprising the NPCA PCH. In an implementation, 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.Docket No.: 25-3004PCT

[0101] In implementations, an NPCA 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 NPCA STA may use the NPCA PCH for transmission if the NPCA PCH is idle (zero NAV and CCA indicates “channel idle”).

[0102] In an implementation, an NPCA STA may support performing CS in parallel on multiple channels, including the PCH and the NPCA PCH. Such an NPCA STA may be referred to herein as a concurrent CCA NPCA 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. In another implementation, an NPCA STA may support performing CS on a single channel at a time. Such a STA may be referred to as a non-concurrent CCA NPCA STA. In an implementation, the NPCA STA may perform CS on the PCH by default. The NPCA STA may perform CS on the NPCA PCH after switching from the PCH to the NPCA PCH. In contrast to a 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.

[0103] A NPCA STA may indicate its support of NPCA operation. In an implementation, to indicate support of NPCA operation, the NPCA STA may set an NPCA Supported field of a UHR MAC Capabilities Information field of a UHR Capabilities element to 1 . The UHR Capabilities element may be provided in an Association Request frame, a Reassociation Request frame, or a Probe Request frame by a non-AP NPCA STA The UHR Capabilities element may be provided in an Association Response frame, a Reassociation Response frame, a Probe Response frame, or a Beacon frame by an NPCA AP.

[0104] An NPCA AP may enable or disable NPCA operation in a BSS. In an implementation, the NPCAAP may enable NPCA operation for the BSS by setting an NPCA Operation Information Present field to 1. The NPCA AP may set the NPCA Operation Information Present field to 0 to indicate that NPCA operation is disabled. The NPCA Operation Information Present field may be a field of a UHR Operation Parameters field of a UHR Operation element. The UHR Operation element may be provided in an Association Response frame, a Reassociation Response frame, a Probe Response frame, or a Beacon frame by the NPCA AP. In an implementation, an NPCA AP that has an operating bandwidth less than 80 MHz (or less than 160 MHz) may not enable NPCA operation.

[0105] An NPCA STA that has enabled NPCA operation may announce NPCA Operation Information in frames that the NPCA STA transmits. In an implementation, the NPCA STA may include an NPCA Operation Information field in the UHR Operation element. The NPCA Operation Information field may include an NPCA Primary Channel field, an NPCA Minimum Duration Threshold field, an NPCA Switching Delay field, and anDocket No.: 25-3004PCTNPCA Switch Back Delay field. The NPCA Primary Channel field indicates a channel number of a channel within the BSS bandwidth that corresponds to the NPCA PCH (the channel to which the NPCA AP and its associated NPCA non-AP STAs switch to perform NPCA operation). The NPCA Minimum Duration Threshold field indicates a minimum duration of inter-BSS activity (inter-BSS PPDU or inter-BSS TXOP) that is required to have been indicated on the primary channel of the BSS as a necessary condition to permit an NPCA STA to switch to the NPCA primary channel to perform NPCA operation. The NPCA Switching Delay field indicates the time needed by the NPCA STA to switch from the BSS primary channel to the NPCA primary channel, e.g., in units of 4 usee. The NPCA Switch Back Delay field indicates the time needed by the NPCA STA to switch from the NPCA primary channel to the BSS primary channel, e.g., in units of 4 usee.

[0106] In an implementation, a non-AP NPCA STA shall not switch to the NPCA primary channel for NPCA operation if the value of the most recently received NPCA Operation Information Present field from its associated AP is equal to 0. An NPCA AP shall not switch to the NPCA primary channel for NPCA operation if the value of its most recently transmitted NPCA Operation Information Present field is equal to 0.

[0107] In an implementation, an NPCA STA may switch to the NPCA primary channel for NPCA operation if the value of the most recently received or transmitted NPCA Operation Information Present subfield corresponding to the BSS of which the NPCA STA is a member if equal to 1 and any of conditions a), b), or c) is met:a) 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 (or one or more) of the following conditions are true:a. the PPDU is classified by the STA as an inter-BSS PPDU following the procedure of Intra-BSS and inter-BSS PPDU classification.b. the duration of the PPDU (e.g., determined using one or more parameters (e.g., TXOP_DURATION) of the RXVECTOR associated with the 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.c. the 20 / 40 / 80 / 160 MHz channel occupied by the PPDU is identified by the STA, based on the Bandwidth field in the PHY preamble of the PPDU and the channel allocations in the corresponding band, and the channel occupied by the PPDU does not overlap with the NPCA primary channel.b) the STA received a PPDU containing a Control frame and / or a PPDU containing an initial response frame of a Control frame exchange on the BSS primary channel and all of the following conditions apply: a. the received PPDU(s) are classified by the STA as inter-BSS PPDU(s) following the procedure of Intra-BSS and inter-BSS PPDU classification.b. the TXOP duration, determined from the Duration field of the received frame(s), 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.Docket No.: 25-3004PCTc. the 20 / 40 / 80 / 160 MHz channel occupied by the received PPDU(s) is identified by the STA based on the channel allocations in the corresponding band and the PPDU bandwidth that is signaled in the received PPDU(s) or obtained from the RXVECTOR parameter CH_BANDWIDTH_IN_NON_HT of the received PPDU(s) and the channel occupied by the received PPDU(s) does not overlap with the NPCA primary channel.I. if the Control frame is an RTS frame in a non-HT (duplicate) PPDU, then it includes a bandwidth signaling TA and the signaled PPDU bandwidth is 20 MHz, 40 MHz, 80 MHz, or 160 MHz.c) The primary channel is known to be busy.

[0108] When an NPCA STA switches to the NPCA primary channel for NPCA operation, the following rules may apply:a) If the STA switches from the BSS primary channel to the NPCA primary channel based on an inter- BSS HE / EHT / UHR PPDU reception on the BSS primary channel, the STA shall initiate the switch at the NPCA HE switch time and it 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.b) If the STA switches from the BSS primary channel to the NPCA primary channel based on an inter- BSS Control frame exchange reception on the primary channel, the STA shall initiate 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.c) The STA shall use the same EDCA parameter set, MU EDCA parameter set, and EPCS EDCA parameter set values for operation on the NPCA primary channel as the STA uses on the BSS primary channel.d) Once the STA becomes ready to transmit on the NPCA primary channel, the STA may initiate a TXOP on the NPCA primary channel by following the rules defined in 10.23.2.2 (EDCA backoff procedure) and 10.23.2.4 (Obtaining an EDCA TXOP) of the IEEE 802.11 standard with the following exceptions: a. Each time that the STA switches to the NPCA primary channel, the STA shall initialize CW_NPCA[AC] to a value to be determined and randomly choose a new initial value between 0 and CW_NPCA[AC] for the backoff counter (BO_NPCA[AC]).b. QSRC_NPCA[AC] shall be set to 0.c. If the STA is a non-AP STA and the associated AP has disabled the use of untriggered UL transmissions on the NPCA primary channel for that STA, then the STA shall not initiate a TXOP on the NPCA primary channel.i.MU EDCA parameters mechanism and or some other mechanism may be used to disable untriggered UL transmissions on the NPCA primary channel.Docket No.: 25-3004PCTii.The baseline EDCA procedure may be followed on the BSS primary channel. The values of CW_NPCA[AC] and BO_NPCA[AC] may be discarded by the NPCA STA when it switches back to the BSS primary channel. e) The STA shall not initiate a transmission on the NPCA primary channel to another STA until the NPCA switching delay time of the other STA has elapsed since the NPCA HE switch time (if switching due to condition a) above) or NPCA NHT switch time (if switching due to condition b) above).f) The STA shall begin all frame exchanges on the NPCA primary channel with an NPCA initial Control frame using non-HT PPDU or non-HT duplicate PPDU format using a rate of 6 Mb / s, 12 Mb / s, or 24 Mb / s. g) An NPCA AP that transmits a Trigger frame on the NPCA primary channel shall indicate RU index values that use the NPCA primary channel as the reference primary channel. The Trigger frame shall include an explicit indication that it is being transmitted on the NPCA primary channel.h) 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 the inter-BSS traffic that 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.e. a frame that solicits a response other than TB PPDUs may puncture 20 MHz subchannels not indicated as punctured in the Disabled Subchannel Bitmap field of the EHT Operation element.

[0109] FIG. 11 shows an example 1100 that illustrates an NPCA operation. As shown in FIG. 11 , example 1100 includes an AP and a STA associated with the AP. The AP and the STA may both support NPCA operation and may operate over a plurality of channels, including a primary channel (PCH), an NPCA primary channel (NPCA PCH), a first secondary channel (SCH1), and a second secondary channel (SCH2).

[0110] Example 1100 may begin with the AP transmitting a frame 1102 on the PCH. Frame 1102 may indicate a medium synchronization duration for the NPCA PCH. The medium synchronization duration of a channel indicates a minimum duration that a STA must listen to the channel before the STA is able to transmit on the channel (if the STA does not receive via the channel before the end of the medium synchronization duration a frame that indicates NAV information). Frame 1102 may be a management frame, such as a beacon frame, for example.

[0111] Subsequently, while the AP and STA operate on the PCH, transmission of a frame 1104 from an OBSS may begin on the PCH. The AP and the STA may detect frame 1104 on the PCH. In an implementation, the AP and STA may be configured to set a NAV associated with the PCH based on receiving frame 1104 on the PCH. Frame 1104 may indicate a transmission (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 1104, aDocket No.: 25-3004PCTtransmission 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).

[0112] 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. 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

[0113] In an implementation, after switching to the NPCA PCH, the AP and STA may start a “MediumSyncDelay” timer for the medium synchronization duration of the NPCA PCH (e.g., as indicated in frame 1102). In example 1100, the AP may be a concurrent CCA STA capable of concurrent CS on both the PCH and the NPCA PCH. As such, provided that the NPCA PCH is idle, the AP may access the NPCA PCH, without waiting for expiration of the "MediumSyncDelay” timer, to transmit a frame 1106 on the NPCA PCH. In 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.

[0114] FIG. 12 shows an example 1200 that illustrates another NPCA operation. As shown in FIG. 12, example 1200 includes an AP 1202 and a STA 1204. STA 1204 may be associated with AP 1202 and may belong to the same BSS as AP 1202. AP 1202 and STA 1204 may both support NPCA operation and may operate over a plurality of channels, including a primary channel (PCH), an NPCA primary channel (NPCA PCH), a first secondary channel (SCH1), and a second secondary channel (SCH2), for example.

[0115] Example 1200 may begin with STA 1204 transmitting a frame 1206 to AP 1202. Frame 1206 may indicate support of NPCA operation by STA 1204. Frame 1206 may comprise an Association Request frame, a Reassociation Request frame, or a Probe Request frame, for example. In an implementation, frame 1206 comprises a UHR Capabilities element. The UHR Capabilities element may comprise a UHR MAC Capabilities Information field. The UHR MAC Capabilities Information field may comprise an NPCA Supported field. In an example, STA 1204 may set the NPCA Supported field 1 to indicate the support of NPCA operation by STA 1204.

[0116] AP 1202 may respond to frame 1206 by transmitting a frame 1208 to STA 1204. Frame 1208 may indicate support of NPCA operation byAP 1202. Frame 1208 may comprise an Association Response frame, a Reassociation Response frame, a Probe Response frame, or a beacon frame, for example. In anDocket No.: 25-3004PCTimplementation, frame 1208 comprises a UHR Capabilities element. The UHR Capabilities element may comprise a UHR MAC Capabilities Information field. The UHR MAC Capabilities Information field may comprise an NPCA Supported field. In an example, AP 1202 may set the NPCA Supported field to 1 to indicate the support of NPCA operation byAP 1202.

[0117] Subsequently, AP 1202 may transmit a frame 1210 indicating enabling / activating of NPCA operation in the BSS. Frame 1210 may comprise a beacon frame, for example. In an implementation, frame 1210 may indicate a time for the enabling / activating of NPCA operation in the BSS. For example, frame 1210 may indicate a number of beacon intervals, e.g., indicated in a Target Beacon Transmission Time (TBTT) Count field, after which NPCA operation will be enabled / activated in the BSS. In an implementation, frame 1210 may comprise a UHR Operation element. The UHR Operation element may comprise a UHR Operation Parameters field. The UHR Operation Parameters field may comprise an NPCA Operation Information Present field. In an example, AP 1202 may set the NPCA Operation Information Present field to 1 to indicate enabling / activating of NPCA operation in the BSS. On receiving frame 1210, STA 1204 may enable / activate NPCA operation. Where frame 1210 indicates a time for the enabling / activating of NPCA operation in the BSS, STA 1204 may enable / activate NPCA operation at / before the indicated time.

[0118] Subsequently, AP 1202 and STA 1204 may detect / receive an inter-BSS PPDU 1212 on the PCH. Inter-BSS PPDU 1212 is transmitted by a STA (not shown in FIG. 12) that belongs to an OBSS relative to the BSS of AP 1202 and STA 1204. Based on the enabling / activating of NPCA operation in the BSS and the detection / reception of inter-BSS PPDU 1212, AP 1202 and STA 1204 switch from the PCH to the NPCA PCH, e.g., after determining a NAV duration from inter-BSS PPDU 1212. After switching to the NPCA PCH, AP 1202 and STA 1204 may communicate via the NPCA PCH. For example, AP 1202 may transmit a frame 1214 to STA 1204. Frame 1214 may comprise a data frame, a control frame, or a management frame. Similarly, STA 1204 may transmit a frame 1216 to AP 1202. Frame 1216 may comprise a data frame, a control frame, or a management frame. AP 1202 and STA 1204 may return to the PCH at / before the end of the NAV duration determined from inter-BSS PPDU 1212.

[0119] FIG. 13 illustrates an example multi-AP network 1300. Example multi-AP network 1300 may be a multi-AP network in accordance with the Wi-Fi Alliance standard specification for multi-AP networks. As shown in FIG. 13, multi-AP network 1300 may include a multi-AP controller 1302 and a plurality of multi-AP groups (or multi-AP sets) 1304, 1306, and 1308.

[0120] Multi-AP controller 1302 may be a logical entity that implements logic for controlling the APs in multi-AP network 1300. Multi-AP controller 1302 may receive capability information and measurements from the APs and may trigger AP control commands and operations on the APs. Multi-AP controller 1302 may also provide onboarding functionality to onboard and provision APs onto multi-AP network 1300.

[0121] Multi-AP groups 1304, 1306, and 1308 may each include a plurality of APs. APs in a multi-AP group are in communication range of each other and may coordinate their transmissions and / or transmissions fromDocket No.: 25-3004PCTtheir associated STAs. Coordinated transmissions may involve all or a subset of the APs in a multi-AP group. A multi-AP group may also be referred to as an AP candidate set as APs in a multi-AP group are considered candidates for a coordinated transmission initiated by an AP. The APs in a multi-AP group are not required to have the same primary channel. As used herein, the primary channel for an AP refers to a default channel that the AP monitors for management frames and / or uses to transmit beacon frames. For a STA associated with an AP, the primary channel refers to the primary channel of the AP, which is advertised through the AP’s beacon frames.

[0122] In one approach, a multi-AP group may be established by a coordinator AP in a multi-AP setup phase prior to any multi-AP coordination. APs of the multi-AP group, other than the coordinator AP, may be referred to as the coordinated APs. A coordinator AP may establish one or more multi-AP groups. A coordinated AP may likewise be a member of multiple multi-AP groups. A coordinator AP of a multi-AP group may be a coordinated AP of another multi-AP group, and vice versa. In another approach, a multi-AP group may be established by a network administrator manually by configuring APs as part of the multi-AP group. In yet another approach, a multi-AP group may be established in a distributed manner by APs without a central controller. In this case, an AP may advertise its multi-AP capability in a beacon or other management frame (e.g., public action frame). Other APs that receive the frame with the multi-AP capability information may perform a multi-AP setup with the AP that advertised the multi-AP capability.

[0123] In one approach, one of the APs in a multi-AP group may be designated as a master AP. The designation of the master AP may be done by AP controller 1302 or by the APs of the multi-AP group. The master AP of a multi-AP group may be fixed or may change over time between the APs of the multi-AP group. An AP that is not the master AP of the multi-AP group is known as a slave AP.

[0124] In one approach, APs in a multi-AP group may perform coordinated transmissions together. One aspect of coordination may include coordination to perform coordinated transmissions within the multi-AP group. As used herein, a coordinated transmission, also referred to as a multi-AP transmission, is a transmission event in which multiple APs (of a multi-AP group or a multi-AP network) transmit in a coordinated manner over a time period. Coordinated transmissions may involve simultaneous transmissions of a plurality of APs in a multi-AP group. The time period of simultaneous AP transmission may be a continuous period. The multi-AP transmission may use different transmission techniques, such as Coordinated OFDMA (COFDMA), Coordinated Spatial Reuse (CSR), Joint Transmission or Reception (JT / JR), Coordinated Beamforming (CBF), and CTDMA, or a combination of two or more of the aforementioned techniques.

[0125] Multi-AP transmissions may be enabled by the AP controller and / or by the master AP of the multi-AP group. In one approach, the AP controller and / or the master AP may control time and / or frequency sharing in a transmission opportunity (TXOP). For example, when one of the APs (e.g., the master AP) in the multi-AP group obtains a TXOP, the AP controller and / or the master AP may control how time / frequency resources of the TXOP are to be shared with other APs of the multi-AP group. In an implementation, the AP of the multiDocket No.: 25-3004PCTAP group that obtains a TXOP becomes the master AP of the multi-AP group. The master AP may then share a portion of its obtained TXOP (which may be the entire TXOP) with one or more other APs of the multi-AP group.

[0126] Different multi-AP transmission schemes may be suitable for different use cases in terms of privacy protection, including whether transmitted data may be shared with other BSSs in the multi-AP group. For example, some multi-AP transmission schemes, such as GSR, CDTMA, coordinated frequency division multiple access (CFDMA), COFDMA, and CBF, enable a master AP to coordinate slave APs by sharing control information among APs, without requiring the sharing of user data among APs. The control information may include BSS information of APs, link quality information of channels between each AP and its associated STAs, and information related to resources to be used to achieve multiplexing in power, time, frequency, or special domains for multi-AP transmission. The control information exchanged among a master AP and slave APs may be used for interference avoidance or nulling to avoid or null co-channel interference introduced to neighboring BSSs in a multi-AP network. Interference avoidance or interference nulling requires that data transmissions between an AP and STAs are only within the same BSS. In other words, each AP transmits or receives data frames to or from its associated STAs, while each STA receives or transmits data frames to or from its associating AP.

[0127] By contrast, other multi-AP transmission schemes may enable a master AP to coordinate slave APs by sharing both control information and user data among APs in a multi-AP group. Control information may include BSS information related to APs and link quality information of channels between each AP and its associated STAs. By having user data exchanged over backhaul, the master AP and slave APs may perform data transmissions jointly to achieve spatial diversity, e.g., using distributed MIMO, for example, joint transmission (JT) for downlink transmissions and joint reception (JR) for uplink transmissions. The data transmissions between APs and STAs may include transmissions within the same BSS and / or across different BSSs. In other words, an AP may transmit or receive data frames to or from its associated STAs as well STAs associated with other APs participating in multi-AP transmission. Similarly, a STA may transmit or receive data frames to or from multiple APs.

[0128] Different multi-AP transmission schemes may be suitable for different use cases in terms of signal reception levels at STAs or APs within a multi-AP group. For example, CBF and JT / JR require that each STA involved in a multi-AP transmission be located within a common area of signal coverage of the APs involved in the multi-AP transmission. Generally, CBF may be suitable when a receiving STA suffers from potential interference from other APs in the multi-AP group. By using channel related information such as channel state information (CSI), channel quality indication (CQI), or compressed beamforming (BF) feedback exchanged among APs, an AP may pre-code a signal to be transmitted to form a beam that increases power toward a target STA while reducing the power that interferes with a STA associated with a neighboring AP. Use cases of JT / JR may require a sufficient received signal power at receiving STAs for JT and a sufficientDocket No.: 25-3004PCTreceived signal power at receiving APs for JR. By contrast, CSR may perform multi-AP transmission in an interference coordination manner. The received signal power at a STA associated with an AP transmitting data may be required to be much higher than the received interference power.

[0129] Different multi-AP transmission schemes may require different synchronization levels and may operate with or without a backhaul between a master AP and slave APs in a multi-AP group. For example, CSR may require PPDU-level synchronization, whereas CBF may require symbol-level synchronization. On the other hand, JT / JR may require tight time / frequency / phase-level synchronization as well as a backhaul for data sharing between APs in the multi-AP group.

[0130] Different multi-AP transmission schemes may have different complexity levels with regard to coordination between a master AP and slave APs in a multi-AP group. For example, JT / JR may require very high complexity due to both CSI and user data being shared between APs. CBF may require medium complexity due to the sharing of CSI. CFDMA, COFDMA and CTDMA may require medium or relatively low complexity due to the CSI and time / frequency resources to be shared between APs. CSR may require low complexity as the amount of information related to spatial reuse and traffic that needs to be exchanged between APs may be low.

[0131] A multi-AP group may adopt a static multi-AP operation including a static multi-AP transmission scheme. A multi-AP network may also be dynamic due to various reasons. For example, a STA may join or leave the multi-AP network, a STA may switch to a power save mode, or an AP or a STA may change its location. Such changes may lead to changes in the conditions underlying the selection of the multi-AP transmission scheme and may cause certain requirements (e.g., synchronization, backhaul, coordination, etc.) for the multi-AP transmission scheme to be lost. This results in an inferior quality of transmissions in the multi-AP network.

[0132] FIG. 14 illustrates an example 1400 of a multi-AP negotiation procedure which may be used to negotiate NPCA operation parameters among multiple APs. As shown in FIG. 14, example 1400 may include an AP 1402, an AP 1404, and an AP 1406. In an example, the multi-AP negotiation procedure may begin with a multi-AP discovery phase, in which AP 1402 transmits a frame 1408 to APs 1404 and 1406. In an example, frame 1408 polls APs 1404 and 1406 regarding joining a multi-AP group with AP 1402. In an example, frame 1408 may further indicate that NPCA operation parameters will be negotiated in the multi-AP group. Frame 1408 may be a broadcast or multicast frame. APs 1404 and 1406 respond to frame 1408 by transmitting to AP 1402 frame 1410 and frame 1412 respectively Frames 1410 and 1412 indicate acceptance or rejection by APs 1404 and 1406 respectively of joining the multi-AP group with AP 1402. In an example, AP 1402 may be referred to as coordinating AP, and APs 1404 and 1406 may be referred to as coordinated APs.

[0133] Subsequently, the multi-AP negotiation procedure may include a multi-AP NPCA negotiation phase, in which AP 1402 negotiates NPCA operation parameters with APs 1404 and 1406. The NPCA operationDocket No.: 25-3004PCTparameters may include a channel number / value for an NPCA PCH for the multi-AP group, a channel bandwidth of the NPCA PCH, and a BSS operating bandwidth. For example, as shown, AP 1402 may transmit a frame 1414 to AP 1404 indicating a first set of NPCA operation parameters. Upon receiving frame 1414, AP 1404 may transmit a frame 1416 to AP 1402 indicating acceptance or rejection of the first set of NPCA operation parameters or indicating a second set NPCA operation parameters. APs 1402 and 1404 may exchange additional frames (not shown in FIG. 14) until agreement is reached on a set of NPCA operation parameters. In example 1400, it is assumed that AP 1404 accepts the first set of NPCA operation parameters indicated in frame 1414.

[0134] After agreeing on the first NPCA operation parameters with AP 1404, AP 1402 may transmit a frame 1418 to AP 1406 indicating the first set of NPCA operation parameters. Upon receiving frame 1418, AP 1406 may transmit a frame 1420 to AP 1402 indicating acceptance or rejection of the first set of NPCA operation parameters or indicating a third set of NPCA operation parameters. APs 1402 and 1406 may exchange additional frames (not shown in FIG. 14) until agreement is reached on a set of NPCA operation parameters. In example 1400, it is assumed that AP 1406 accepts the first set of NPCA operation parameters indicated in frame 1418. Thus, the multi-AP NPCA negotiation phase ends with frame 1420, and APs 1402, 1404, and 1406 may begin using the negotiated first set of NPCA operation parameters. In an implementation, if the NPCA operation parameters agreed between APs 1402 and 1406 is inconsistent with the NPCA operation parameters agreed between APs 1402 and 1404, AP 1402 may continue the multi-AP NPCA negotiation with AP 1404 and / or AP 1406 in order to agree on consistent / same NPCA operation parameters with both APs 1404 and 1406.

[0135] FIG. 15 shows an example 1500 that illustrates a problem that may arise with the use of multi-AP NPCA negotiation described in FIG. 14. As shown in FIG. 15, example 1500 includes an AP 1502 and an AP 1504. APs 1502 and 1504 may form a multi-AP group and may operate on the same PCH and NPCA PCH. For example, before example 1500, APs 1502 and 1504 may have performed a multi-AP negotiation procedure such as illustrated by example 1400 to negotiate NPCA operation parameters, including the channel / value of the NPCA PCH. Additionally, it is assumed in example 1500 that NPCA operation is enabled at both APs 1502 and 1504.

[0136] Example 1500 begins with APs 1502 and 1504 operating on the PCH. In an example, low latency traffic may arrive at AP 1502. The low latency traffic may be associated with a transmission deadline 1507. AP 1502 may be configured to contend for the PCH to transmit the low latency traffic. However, due to an OBSS PPDU 1506 detected on the PCH, AP 1502 set a NAV 1509 for the PCH based on OBSS PPDU 1506 and switches to the NPCA PCH channel.

[0137] In an example, AP 1504 may have non-low latency traffic buffered for transmission. AP 1504 may also be configured to contend for the PCH to transmit the non-low latency traffic. On detecting OBSS PPDUDocket No.: 25-3004PCT1506, AP 1504 sets a NAV 1511 for the PCH based on OBSS PPDU 1506 and switches to the NPCA PCH channel.

[0138] In an example, APs 1502 and 1504 switch at substantially the same time to the NPCA PCH and both contend for NPCA PCH after switching. In example 1500, AP 1504 gains access to the NPCA PCH and proceed to transmit a frame 1508 with the non-low latency traffic on the NPCA PCH. In an example, transmission of frame 1508 transmission may extend beyond transmission deadline 1507 of the low latency traffic buffered at AP 1504, thereby preventing AP 1502 from transmitting the low latency traffic by transmission deadline 1507. This may result in the low latency traffic being discarded by AP 1502. In another example, at expiration of NAV 1509 set for the PCH, AP 1502 returns to the PCH and transmits a frame 1510 with the low latency traffic on the PCH. However, this may be an untimely transmission for the low latency traffic of AP 1502.

[0139] Embodiments of the present disclosure, as further described below, address the above-discussed problem of existing technologies. In an aspect, a first AP may transmit to a second AP a first frame indicating whether NPCA operation is enabled (or is to be enabled, or is permitted to be enabled) at the second AP. The first AP may be a coordinating AP, and the second AP may be a coordinated AP. In an embodiment, the first frame comprises schedule information for NPCA operation by the second AP. In an embodiment, the schedule information indicates a first time period during which the second AP enables NPCA operation. In an embodiment, the schedule information indicates a second time period during which the second AP disables NPCA operation. In an embodiment, the second AP may transmit to the first AP a second frame indicating acceptance or rejection of the schedule information or indicating modified schedule information. As such, embodiments enable the first AP to control NPCA operation at the second AP. In an example, the first AP may control NPCA operation at the second AP to reduce contention by the second AP for the NPCA PCH when desired (e.g., when the first AP anticipates arrival or has buffered low latency traffic).

[0140] FIG. 16 illustrates an example 1600 of procedure according to an embodiment. The procedure illustrated in FIG. 16 may be used to enable coordinated NPCA (Co-NPCA) operation, according to which multiple APs may coordinate NPCA operation. This may include an AP controlling the NPCA operation of one or more APs and / or the AP coordinating its NPCA operation with the NPCA operation of the one or more APs. Example 1600 is provided for the purpose of illustration only and is not limiting of embodiments of the present disclosure. As shown in FIG. 16, example 1600 may include an AP 1602 and an AP 1604. In an embodiment, each of AP 1602 and AP 1604 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. In an embodiment, APs 1602 and 1604 may form a multi-AP group. AP 1602 may be coordinating AP of the multi-AP group, and AP 1604 may be a coordinated AP of the multi-AP group. In an embodiment, AP 1602 and AP 1604 may be configured to operate on the same PCH and NPCH PCH channels.Docket No.: 25-3004PCT

[0141] Example 1600 may begin with AP 1602 transmitting a frame 1606 to AP 1604. In an embodiment, frame 1606 may comprise a request to form a multi-AP group. Frame 1606 may be a broadcast or multicast frame. In an embodiment, frame 1606 maybe be a management frame that advertises multi-AP coordination capabilities (and associated parameters) of AP 1602. In an embodiment, frame 1606 may indicate a request by AP 1602 to initiate a discovery phase for Co-NPCA operation. During the discovery phase, AP 1602 discovers AP(s) of the multi-AP group that accept to participate in Co-NPCA operation. In an embodiment, AP 1602 may receive a response to frame 1606 from AP(s) of the multi-AP group indicating acceptance or rejection of participation in Co-NPCA operation. In an embodiment, in accordance with Co-NPCA, multiple APs may coordinate NPCA operation among each other.

[0142] Upon receiving frame 1606, AP 1604 may transmit a frame 1608 to AP 1602. In an embodiment, frame 1608 indicates acceptance or rejection by AP 1604 of the request, in frame 1606, to form a multi-AP group. Alternatively, or additionally, frame 1608 indicates acceptance or rejection of the request, in frame 1606, to participate in Co-NPCA operation. In an embodiment, frame 1608 may be a management frame.

[0143] In an embodiment, example 1600 may further include AP 1602 transmitting a frame 1610 to AP 1604 indicating whether NPCA operation is enabled at AP 1604. In an embodiment, frame 1610 may comprise a field indicating whether NPCA operation is enabled at AP 1604. In an embodiment, frame 1610 may indicate that AP 1604 is to enable or disable NPCA operation. In another embodiment, frame 1610 may comprise a request that AP 1604 enable or disable NPCA operation. In an embodiment, AP 1602 may transmit frame 1610 after receiving from AP 1604 frame 1608 indicating acceptance of AP 1604 to form the multi-AP group and / or acceptance of AP 1604 to participate in Co-NPCA operation with AP 1602. In an embodiment, frame 1610 may be a management or action frame. As a management frame, frame 1610 may be an individually addressed management frame (e.g., addressed to AP 1604).

[0144] On receiving frame 1610, AP 1604 may transmit a frame 1612 to AP 1602. In an embodiment, where frame 1610 indicates that AP 1604 is to enable or disable NPCA operation, frame 1612 may acknowledge frame 1610 and may indicate that AP 1604 enabled or disabled NPCA operation. In another embodiment, wherein frame 1610 comprises a request that AP 1604 enable or disable NPCA operation, frame 1612 may indicate acceptance or rejection of the request in frame 1610. In an embodiment, frame 1612 may be a management or action frame.

[0145] In example 1600, anticipating arrival of low latency traffic, AP 1602 may enable its NPCA operation and may indicate disablement of NPCA operation at AP 1604, in frame 1610, for a time interval 1617. AP 1604 disables NPCA operation on receiving frame 1610. Subsequently, during time interval 1617, low latency traffic with a transmission deadline 1613 arrives at AP 1602. AP 1602 may attempt to transmit the low latency traffic on the PCH. However, due to an OBSS PPDU 1614 transmitted on the PCH, AP 1602 does not gain access to the PCH. Instead, with NPCA operation enabled, after setting a NAV 1615 for the PCH based on OBSS PPDU 1614, AP 1602 switches from the PCH to the NPCA PCH and contends for the NPCA PCH toDocket No.: 25-3004PCTtransmit the low latency traffic. AP 1604 also detects OBSS PPDU 1614 on the PCH. But with NPCA operation disabled, AP 1604 sets a NAV 1611 for the PCH based on OBSS PPDU 1614 but does not switch from the PCH to the NPCA PCH based on detecting OBSS PPDU 1614. As such, AP 1602 may contend for the NPCA PCH, with no contention from AP 1604, to transmit the low latency traffic. Accordingly, as shown in FIG. 16, AP 1602 successfully gains access to the NPCA PCH and transmits a frame 1616 comprising the low latency traffic before transmission deadline 1613.

[0146] Subsequently, AP 1602 returns to the PCH at / before expiration of NAV 1615 and may transmit a frame 1618 to AP 1604. In example 1600, frame 1618 may indicate to AP 1604 to enable NPCA operation. In an embodiment, frame 1618 may indicate a time interval 1619 during which AP 1604 is to enable NPCA operation. On receiving frame 1618, AP 1604 may transmit a frame 1620 to AP 1602. Frame 1620 may acknowledge frame 1618 and may indicate that AP 1604 enabled NPCA operation. In another example (not shown in FIG. 16), frame 1618 may indicate that AP 1604 may enable NPCA operation (or that AP 1604 is permitted to enable NPCA operation). AP 1604 may determine whether to enable NPCA operation based on receiving frame 1618.

[0147] In example 1600, an OBSS PPDU 1622 is detected by AP 1602 and AP 1604 during time interval 1619. APs 1602 and 1604 set respective NAVs 1623 and 1625 for the PCH based on OBSS PPDU 1622, and with NPCA operation enabled at both APs 1602 and 1604, both AP 1602 and AP 1604 switch from the PCH to the NPCA PCH channel based on OBSS PPDU 1622. In example 1600, AP 1602 may have no low latency traffic to transmit and, as such, may not contend for the NPCA PCH. In contrast, with traffic to transmit, AP 1604 may contend and win channel access and proceed to transmit a frame 1624 on the NPCA PCH. In another example (not shown in FIG. 16), AP 1602 may disable its NPCA operation during time interval 1619 during which AP 1602 enables NPCA operation at AP 1604. As such, AP 1602 does not switch to the NPCA PCH based on OBSS PPDU 1622. AP 1604 may thus contend unchallenged for the NPCA PCH to transmit frame 1624.

[0148] FIG. 17 illustrates an example 1700 of another procedure according to an embodiment. The procedure illustrated in FIG. 17 may be used to enable coordinated NPCA (Co-NPCA) operation, according to which multiple APs may coordinate NPCA operation. This may include an AP controlling the NPCA operation of one or more APs and / or the AP coordinating its NPCA operation with the NPCA operation of the one or more APs. Example 1700 is provided for the purpose of illustration only and is not limiting of embodiments of the present disclosure. As shown in FIG. 17, example 1700 may also include AP 1602 and AP 1604 described with reference to FIG. 16 above.

[0149] Example 1700 may begin with AP 1602 transmitting frame 1606 (described above) to AP 1604. Upon receiving frame 1606, AP 1604 may transmit frame 1608 (described above) to AP 1604. In example 1700, frame 1606 may comprise a request by AP 1602 to initiate a discovery phase for Co-NPCA operation. Frame 1608 may indicate acceptance by AP 1604 to participate in Co-NPCA operation with AP 1602.Docket No.: 25-3004PCT

[0150] In an embodiment, example 1700 may further include AP 1602 transmitting a frame 1702 to AP 1604 to indicate whether NPCA operation is enabled at AP 1604. In an example, frame 1702 may be an embodiment of frame 1610. In an embodiment, frame 1702 may comprise schedule information for NPCA operation by AP 1604. In an embodiment, the schedule operation may indicate a first time period 1708 during which AP 1604 enables (or is to enable, or is permitted to enable) NPCA operation. Alternatively, or additionally, the schedule operation may indicate a second time period 1712 during which AP 1604 disables (or is to disable, or is permitted to disable) NPCA operation. In an example, frame 1702 further indicates a start time 1706 of first time period 1708 and an end time 1710 of first time period 1708. In an embodiment, frame 1702 further indicates a start time 1711 of second time period 1712 and an end time 1716 of second time period 1712. In an embodiment, AP 1602 disables NPCA operation during first time period 1708. In an embodiment, AP 1602 enables NPCA operation during second time period 1712.

[0151] In an embodiment the schedule information further indicates a periodicity of first time period 1708. The periodicity of first time period 1708 may correspond to a time interval 1714 between successive first time periods during which AP 1604 enables NPCA operation. Alternatively, or additionally, the schedule information may indicate a periodicity of second time period 1712. The periodicity of second time period 1712 may correspond to a time interval (not shown in FIG. 17) between successive second time periods during which AP 1604 disables NPCA operation. In an embodiment, frame 1702 comprises an NPCA schedule information element that comprises the schedule information.

[0152] Upon receiving frame 1702, AP 1604 transmits frame 1704 to indicate acceptance or rejection of the schedule information. In an example, frame 1704 may be an embodiment of frame 1612.

[0153] FIG. 18 illustrates an example 1800 of another procedure according to an embodiment. The procedure illustrated in FIG. 18 may be used to enable coordinated NPCA (Co-NPCA) operation, according to which multiple APs may coordinate NPCA operation. This may include an AP controlling the NPCA operation of one or more APs and / or the AP coordinating its NPCA operation with the NPCA operation of the one or more APs. Example 1800 is provided for the purpose of illustration only and is not limiting of embodiments of the present disclosure. As shown in FIG. 18, example 1800 may include AP 1602 and AP 1604 described with reference to FIG. 16 above, and a STA 1805, where STA 1805 may be associated to AP 1604. In an embodiment, STA 1805 may be an MLD. In an embodiment, AP 1602, AP 1604, and STA 1805 may be configured to operate on the same PCH and NPCH PCH channels.

[0154] Example 1800 may begin with AP 1602 transmitting frame 1606 (described above) to AP 1604. Upon receiving frame 1606, AP 1604 may transmit frame 1608 (described above) to AP 1604.. In example 1800, frame 1606 may comprise a request by AP 1602 to initiate a discovery phase for Co-NPCA operation. Frame 1608 may indicate acceptance by AP 1604 to participate in Co-NPCA operation with AP 1602.

[0155] In an embodiment, example 1800 may further include AP 1602 transmitting frame 1702 (described above) to AP 1604 comprising schedule information for NPCA operation by AP 1604. On receiving frameDocket No.: 25-3004PCT1702, AP 1604 may transmit frame 1704 (described above) to indicate acceptance or rejection of the schedule information. In example 1800, it is assumed that AP 1604 accepts the schedule information indicated in frame 1702.

[0156] In an embodiment, after transmitting frame 1704 accepting the scheduling information, AP 1604 may transmit a frame 1806 to STA 1802 comprising the schedule information. In an embodiment, frame 1806 may comprise a management frame or an action frame.

[0157] In an embodiment, AP 1602 may modify the schedule information, e.g., based on changes in network conditions, traffic conditions, etc. For example, as shown in FIG. 18, AP 1602 may transmit a frame 1808 comprising modified schedule information to AP 1604. The modified schedule information may comprise a modified first time period and / or a modified second time period. In an embodiment, frame 1808 comprises a field to indicate that frame 1808 comprises the modified schedule information. In another embodiment, frame 1808 may request a modified schedule information from AP 1604. In an embodiment where frame 1808 comprises a modified schedule information, on receiving frame 1808, AP 1604 may transmit a frame 1810 to AP 1602 to acknowledge the reception of frame 1808 and indicate acceptance or rejection of the modified schedule information. In an embodiment where frame 1808 comprises a request for modified schedule information from AP 1604, frame 1810 indicates acceptance or rejection of the request and, where the request is accepted, may comprise modified schedule information. In an embodiment, after transmitting frame 1810, AP 1604 may transmit a frame 1812 to STA 1805 to indicate the modified schedule information.

[0158] In an embodiment, example 1800 may further include AP 1604 transmitting a frame 1814 to AP 1602 to indicate a modified schedule information. In another embodiment, frame 1814 may comprise a request to modify the schedule information. In another embodiment, the request in frame 1814 may comprise modified schedule information.

[0159] In an embodiment where frame 1814 indicates the modified schedule information AP 1602 may transmit a frame 1816 to AP 1604 to acknowledge reception of frame 1814 and indicate acceptance or rejection of the modified schedule. In another embodiment where frame comprises a request to modify the schedule information, AP 1602 may transmit frame 1816 to AP 1604 to indicate acceptance or rejection of the request. On receiving frame 1816, AP 1604 may transmit a frame 1818 to STA 1805 to indicate the modified schedule information.

[0160] FIG. 19 illustrates an example 1900 of another procedure according to an embodiment. The procedure illustrated in FIG 19 may be used to enable coordinated NPCA (Co-NPCA) operation, according to which multiple APs may coordinate NPCA operation. This may include an AP controlling the NPCA operation of one or more APs and / or the AP coordinating its NPCA operation with the NPCA operation of the one or more APs. Example 1900 is provided for the purpose of illustration only and is not limiting of embodiments of the present disclosure. As shown in FIG. 19, example 1900 may also include AP 1602 and AP 1604 described with reference to FIG. 16 above.Docket No.: 25-3004PCT

[0161] Example 1900 begins with NPCA operation enabled at AP 1602 and disabled at AP 1604 for a time period 1904. Subsequently, AP 1602 and AP 1604 detect an OBSS PPDU 1902 on the PCH and set respective NAVs 1908 and 1909 for the PCH based on OBSS PPDU 1902. With NPCA operation enabled at AP 1602, upon detecting OBSS PPDU 1902, AP 1602 switches to the NPCA PCH and contends for access. In example 1900, AP 1602 gains access to the NPCA PCH and proceeds to transmit a frame 1906, e.g., to a STA associated with AP 1602. In contrast, with NPCA operation disabled at AP 1604, AP 1604 does not switch from the PCH to the NPCA PCH on detecting OBSS PPDU 1902.

[0162] Upon expiry of NAV 1908, AP 1602 returns to the PCH. In an example, after returning to the PCH, AP 1604 obtains a TXOP 1910 on PCH by transmitting a frame 1912 to AP 1604. Frame 1912 may be an embodiment of frame 1610 described above. In example 1900, frame 1912 indicates enablement of NPCA operation at AP 1604. Frame 1912 may further indicate a first time period 1918 during which NPCA operation is enabled at AP 1604. In an embodiment, frame 1912 comprises an initial control frame (ICF). In an embodiment, the ICF may comprise a request-to-send (RTS) frame or a clear-to-send (CTS)-to-self frame. In an embodiment, the ICF comprises a duration field that indicates first time period 1918 during which AP 1604 enables NPCA operation.

[0163] Subsequently, as owner of TXOP 1910, AP 1602 transmits a frame 1920 (e.g., to a STA associated with AP 1602) on the PCH. AP 1604 detects frame 1920 on the PCH, sets a NAV 1922 for the PCH based on frame 1920, and, with NPCA operation enabled, switches to the NPCA PCH based on frame 1920. In an example, after switching to the NPCA PCH, AP 1604 contends and gains channel access and proceeds to transmit a frame 1916, e.g., to a STA associated with AP 1604.

[0164] As described above, the Co-NPCA procedure illustrated by example 1900 allows a AP 1602 to enable NPCA operation at AP 1604 in the same frame (e.g., frame 1912) that initiates TXOP 1910 for AP 1602 on the PCH. As such, AP 1604 may switch from the PCH to the NPCA PCH upon detecting a subsequent PPDU (e.g., frame 1920) from AP 1602. In another embodiment (not shown in FIG. 19), AP 1604 may be configured to enable NPCA operation as well as switch from the PCH to the NPCA PCH based on the frame (e.g., frame 1912) that initiates TXOP 1910 for AP 1602 on the PCH. For example, AP 1604 may be configured to switch from the PCH to the NPCA PCH based on frame 1912 if frame 1912 indicates a NAV setting duration greater than a threshold.

[0165] FIG. 20 illustrates an example process 2000 according to an embodiment. Example process 2000 is provided for the purpose of illustration only and is not limiting embodiments. Process 2000 may be performed by a first AP, such as AP 1602 illustrated in FIGS. 16-19. As shown in FIG. 20, process 2000 may comprise step 2002.

[0166] Step 2002 comprises transmitting, by the first AP to a second AP, a first frame indicating whether NPCA operation is enabled at the second AP. In an embodiment, the first AP and the second AP form a multi-AP group.Docket No.: 25-3004PCT

[0167] In an embodiment, the first AP comprises a coordinating AP. In an embodiment, the second AP comprises a coordinated AP.

[0168] In an embodiment, the first frame comprises a management frame or an action frame.

[0169] In an embodiment, the first frame comprises schedule information for NPCA operation by the second AP. In an embodiment, the schedule information indicates a first time period during which the second AP enables NPCA operation. In an embodiment, the schedule information further indicates a start time of the first time period. In an embodiment, the schedule information further indicates an end time of the first time period. In an embodiment, process 2000 further comprises disabling, by the first AP, NPCA operation during the first time period.

[0170] In an embodiment, the schedule information indicates a second time period during which the second AP disables NPCA operation. In an embodiment, the schedule information further indicates a start time of the second time period. In an embodiment, the schedule information further indicates an end time of the second time period. In an embodiment, process 2000 further comprises enabling, by the first AP, NPCA operation during the second time period.

[0171] In an embodiment, the first frame comprises a field that indicates whether NPCA operation is enabled at the second AP.

[0172] In an embodiment, the schedule information indicates a periodicity of the first time period. In an embodiment, the schedule information indicates a time interval between successive first time periods during which the second AP enables NPCA operation.

[0173] In an embodiment, the first frame comprises an NPCA schedule information element that comprises the schedule information.

[0174] In an embodiment, process 2000 further comprises receiving, by the first AP from the second AP, a second frame indicating acceptance or rejection of the schedule information.

[0175] In an embodiment, process 2000 further comprises receiving, by the first AP from the second AP, a second frame indicating modified schedule information. In an embodiment, process 2000 further comprises receiving, by the first AP from the second AP, a second frame comprising a request to modify the schedule information. In an embodiment, the request comprises modified schedule information. In an embodiment, process 2000 further comprises transmitting, by the first AP to the second AP, a third frame accepting or rejecting the request.

[0176] In an embodiment, process 2000 further comprises transmitting, by the first AP to the second AP, a second frame indicating modified schedule information.

[0177] In an embodiment, process 2000 further comprises transmitting, by the first AP to the second AP, a third frame comprising a request to form a multi-AP group. In an embodiment, process 2000 further comprises receiving , by the first AP from the second AP, a fourth frame indicating acceptance or rejection of the request.Docket No.: 25-3004PCT

[0178] In an embodiment, the first frame comprises a request to form a multi-AP group with the second AP. In an embodiment, process 2000 further comprises receiving, by the first AP from the second AP, a third frame indicating acceptance or rejection of the request.

[0179] In an embodiment, the first frame comprises an initial control frame (ICF). In an embodiment, the first AP obtains a transmission opportunity (TXOP) on a primary channel (PCH) after transmitting the ICF. In an embodiment, the ICF comprises a duration field that indicates a first time period during which the second AP enables NPCA operation.

[0180] FIG. 21 illustrates an example process 2100 according to an embodiment. Example process 2100 is provided for the purpose of illustration only and is not limiting embodiments. Process 2100 may be performed by a first AP, such as AP 1604 illustrated in FIGS. 16-19. As shown in FIG. 21, process 2100 may comprise step 2102.

[0181] Step 2102 comprises receiving, by the first AP from a second AP, a first frame indicating whether NPCA operation is enabled at the first AP.

[0182] In an embodiment, the first AP comprises a coordinated AP. In an embodiment, the second AP comprises a coordinating AP.

[0183] In an embodiment, the first frame comprises a management frame or an action frame.

[0184] In an embodiment, the first frame comprises schedule information for NPCA operation by the first AP. In an embodiment, the schedule information indicates a first time period during which the first AP enables NPCA operation. In an embodiment, the schedule information further indicates a start time of the first time period. In an embodiment, the schedule information further indicates an end time of the first time period. In an embodiment, process 2100 further comprises enabling, by the first AP, NPCA operation during the first time period.

[0185] In an embodiment, the schedule information indicates a second time period during which the first AP disables NPCA operation. In an embodiment, the schedule information further indicates a start time of the second time period. In an embodiment, the schedule information further indicates an end time of the second time period. In an embodiment, process 2100 further comprises disabling, by the first AP, NPCA operation during the second time period.

[0186] In an embodiment, the first frame comprises a field that indicates whether NPCA operation is enabled at the first AP.

[0187] In an embodiment, the schedule information indicates a periodicity of the first time period. In an embodiment, the schedule information indicates a time interval between successive first time periods during which the first AP enables NPCA operation. In an embodiment, the first frame comprises an NPCA schedule information element that comprises the schedule information.

[0188] In an embodiment, process 2100 further comprises transmitting, by the first AP to the second AP, a second frame indicating acceptance or rejection of the schedule information.Docket No.: 25-3004PCT

[0189] In an embodiment, process 2100 further comprises transmitting, by the first AP to a STA associated to the first AP, a third frame comprising the schedule information.

[0190] In an embodiment, process 2100 further comprises transmitting, by the first AP to the second AP, a second frame indicating modified schedule information.

[0191] In an embodiment, process 2100 further comprises transmitting, by the first AP to the second AP, a second frame comprising a request to modify the schedule information. In an embodiment, the request comprises modified schedule information. In an embodiment, process 2100 further comprises receiving, by the first AP from the second AP, a third frame accepting or rejecting the request.

[0192] In an embodiment, process 2100 further comprises transmitting, by the first AP to a STA associated to the first AP, a fourth frame comprising the modified schedule information.

[0193] In an embodiment, process 2100 further comprises receiving, by the first AP from the second AP, a second frame indicating modified schedule information. In an embodiment, process 2100 further comprising transmitting, by the first AP to a STA associated to the first AP, a third frame comprising the schedule information.

[0194] In an embodiment, process 2100 further comprising receiving, by the first AP from the second AP, a fourth frame comprising a request to form a multi-AP group. In an embodiment, process 2100 further comprising transmitting, by the first AP to the second AP, a fifth frame indicating acceptance or rejection of the request.

[0195] In an embodiment, the first frame comprises a request to form a multi-AP group with the first AP. In an embodiment, process 2100 further comprising transmitting, by the first AP to the second AP, a third frame indicating acceptance or rejection of the request.

[0196] In an embodiment, the first frame comprises an initial control frame (ICF). In an embodiment, the second AP obtains a transmission opportunity (TXOP) on a primary channel (PCH) after transmitting the ICF. In an embodiment, the ICF comprises a duration field that indicates a first time period during which the first AP enables NPCA operation.

[0197] 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 any of FIGS. 16-21 may switch to the NPCA primary channel for NPCA operation if either condition 1) or 2), described below, is met.

[0198] 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 STADocket No.: 25-3004PCTdoes not enable the NPCA mode unless the non-AP NPCA STA is associated with an NPCA AP that has enabled NPCA operation.

[0199] 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.

[0200] 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.

[0201] In an implementation, an NPCA AP with a value (e.g., dotHHEPSROption Implemented) set to true may set the TXVECTOR parameter SPATIAL_REUSE to PSR_DISALLOW for PPDUs that it transmits, and may set the PSR Disallowed subfield in the SR Control field of the Spatial Reuse Parameter Set element to 1 in Management frames it transmits before enabling NPCA operation in its BSS and while NPCA operation remains enabled.

[0202] 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.

[0203] In an implementation, an NPCA AP may advertise an NPCA Disabled Subchannel Bitmap field in the NPCA Operation Parameters field. The NPCA Disabled Subchannel Bitmap field may indicate the subchannels that are punctured when an NPCA STA operates on the NPCA primary channel:If an NPCA Disabled Subchannel Bitmap field is present, then the NPCA Disabled Subchannel Bitmap Field Present bit may be set to 1 , otherwise the NPCA Disabled Subchannel Bitmap Field Present field may be set to 0.The NPCA Disabled Subchannel Bitmap field value may satisfy the following requirements:• The puncturing pattern indicated by the value of the NPCA Disabled Subchannel Bitmap field is a valid non-OFDMA puncturing pattern.• A 20 MHz subchannel indicated as punctured in the Disabled Subchannel Bitmap field of an EHT Operation element (if any) is also indicated as punctured in the NPCA Disabled Subchannel Bitmap field.An NPCA AP may indicate one or more 20 MHz subchannels as punctured in the NPCA Disabled Subchannel Bitmap field of the EHT Operation Element for the purpose of maximizing the BW of the NPCA operating channel.Docket No.: 25-3004PCTAn 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.

[0204] 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, thatcorresponds 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.

[0205] 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.

[0206] 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.

[0207] 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.

[0208] 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.

[0209] 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.: 25-3004PCT

[0210] 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.: 25-3004PCTii) 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.

[0211] 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.In an implementation, the MAC variable NPCA_PPDU_REM_DUR derived from a received PPDU is equal to the value in usee, of the remaining duration of the received PPDU, determined by the MAC at the time of the receipt of the PHY-RXSTART. indication primitive associated with the received PPDU, by subtracting the time elapsed between the reception of the PHY-CCA.indication(BUSY) and PHY-RXSTART. indication primitives associated with the received PPDU from the value of RXTIME of the received PPDU.

[0212] 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.: 25-3004PCTOtherwise, 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.

[0213] 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.

[0214] 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.: 25-3004PCTdisabled 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 the NPCA 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 leastone ofthe 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.: 25-3004PCT9) The 20 MHz channels occupied by PPDUs transmitted by the STA shall meet all of the following conditions:a) include at least the NPCA primary channel.b) all be within the BSS bandwidth.c) not include any of the channels occupied by either the PPDU mentioned in condition 1) or by the third PPDU mentioned in condition 2), whichever caused the STA to switch from the BSS primary channel to the NPCA primary channel.d) not include channels that are indicated as punctured in the Disabled Subchannel Bitmap field in the EHT Operation element or in the NPCA Disabled Subchannel Bitmap field in the UHR Operation element.10) UHR ELR PPDUs, HE ER SU PPDUs, EHT MCS14 / 15 shall not be transmitted on the NPCA primary channel.11) Dynamic Subband Operation shall not be used on the NPCA primary channel.12) If TBTT for the BSS occurs while an NPCA AP is operating on the NPCA primary channel, the scheduling of the transmission of the Beacon frame and following group addressed frames shall be deferred until immediately after the AP switches back to the BSS primary channel.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.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.

[0215] In an embodiment, an AP or STA in accordance with the above-described embodiments (e.g., any AP or STA as described in any of FIGs. 16-21) may perform operations according to an MAPC framework as described below. A person of skill in the art based on the teachings herein would appreciate that the below described features and operations may be readily combined with the above-described embodiments.

[0216] The MAPC framework includes a set of schemes, including Co-BF, Co-SR, Co-TDMA, Co-RTWT, and Co-CR, and associated procedures in which access points (APs) operating their basic service sets (BBSs) on the same primary 20 MHz channel coordinate to reduce interference levels and to improve network performance, including medium utilization efficiency, communication reliability, and latency.

[0217] An AP may use a MAPC scheme with another AP if the AP has established an agreement for that MAPC scheme by following common MAPC procedures or via other means outside the scope of this description.Docket No.: 25-3004PCT

[0218] The common procedures described herein are applicable to all MAPC coordination schemes. MAPC discovery procedures enable APs to advertise and discover MAPC capabilities and parameters. MAPC agreement negotiation procedures enable APs to establish, update, or tear down MAPC agreements. Procedures that are specific to individual coordination schemes may be performed separately.

[0219] In some examples, two APs that belong to the same extended service set (ESS) may enable the use of MAPC schemes via mechanisms other than MAPC discovery and MAPC agreement negotiation procedures.

[0220] MAPC discovery procedures enable APs to advertise and discover MAPC capabilities and MAPC parameters of other APs.

[0221] An AP may advertise its MAPC capabilities, common MAPC parameters, and parameters specific to MAPC schemes by transmitting a MAPC Discovery Request frame to a broadcast address or as an individually addressed frame to another AP.

[0222] If an AP receives a soliciting MAPC Discovery Request frame from a transmitting AP, the receiving AP may respond by sending a MAPC Discovery Response frame to a broadcast address or as an individually addressed Management frame to the transmitting AP. A value of a Dialog Token field of the MAPC Discovery Response frame may be set equal to a value of a Dialog T oken field of the soliciting APC Discovery Request frame.

[0223] An AP that transmits a MAPC Discovery Request frame or a MAPC Discovery Response frame may include a Per-Scheme Profile subelement in a reported MAPC element for each MAPC scheme for which the AP signals capability. The AP may omit a MAPC Scheme Request Set field in the reported Per-Scheme Profile subelements.

[0224] If an AP that transmits a MAPC Discovery Request frame or a MAPC Discovery Response frame to a peer AP sets a MAPC Security Supported field carried in the MAPC element to a value of one, the AP may include a Robust Security Network Element (RSNE) field and a Robust Security Network Extension Element (RSNXE) field in a Security Profile subelement of the MAPC element.

[0225] MAPC agreement negotiation procedures enable establishment, update, or teardown of MAPC agreements through negotiation. An AP may follow the procedures described herein, in addition to schemespecific procedures, to establish, update, or tear down MAPC agreements.

[0226] A MAPC requesting AP is an AP that initiates a MAPC negotiation for one or more MAPC schemes with another AP. A MAPC requesting AP may refrain from initiating a MAPC negotiation for a specific MAPC scheme with a peer AP if the peer AP indicates non-support for that MAPC scheme in a MAPC Common Info field reported in a most recently received MAPC Discovery Request frame, MAPC Discovery Response frame, or MAPC Negotiation Request frame.

[0227] A MAPC responding AP is an AP that responds to a MAPC requesting AP.Docket No.: 25-3004PCT

[0228] A MARC requesting AR may initiate a MARC negotiation for one or more MARC schemes by sending an individually addressed MARC Negotiation Request frame to another AR. The MARC Negotiation Request frame may include a MAPC element including at least one Per-Scheme Profile subelement in a MAPC Schemes Info field. A Per-Scheme Profile subelement for a specific MAPC scheme may be omitted if the MAPC requesting AR has not indicated support for that MAPC scheme in a MAPC Capabilities field carried in the MAPC element. When a Per-Scheme Profile subelement is included, the Per-Scheme Profile subelement may carry a MAPC Scheme Request Set field including at least one MAPC Scheme Request field.

[0229] Each Per-Scheme Profile subelement of the MAPC Schemes Info field in a MAPC Negotiation Request frame may carry one or more requests for a specific MAPC scheme.

[0230] A MAPC responding AP that receives an individually addressed MAPC Negotiation Request frame from a MAPC requesting AP may respond by sending an individually addressed MAPC Negotiation Response frame to the MAPC requesting AP. A value of a Dialog Token field of the MAPC Negotiation Response frame may be set equal to a value of a Dialog Token field of the MAPC Negotiation Request frame.

[0231] A Status Code field of the MAPC Negotiation Response frame may be set to SUCCESS if the MAPC responding AP accepts at least one request carried in the received MAPC Negotiation Request frame. Otherwise, the MAPC responding AP may set a Status Code field to indicate a rejection status code.

[0232] The MAPC Negotiation Response frame may include a MAPC element including one Per-Scheme Profile subelement in a MAPC Schemes Info field for each Per-Scheme Profile subelement included by the MAPC requesting AP in the MAPC Negotiation Request frame.

[0233] In the MAPC Negotiation Response frame, each Per-Scheme Profile subelement may include a MAPC Scheme Request field with a MAPC Operation Type field set to a value of 3, 4, or 5. If the MAPC Operation Type field is set to 3 or 4, a MAPC Request Parameter Set field may be omitted. A MAPC Operation Type field set to 3 may indicate acceptance of a request. A MAPC Operation Type field set to 4 may indicate rejection of a request. A MAPC Operation Type field set to 5 may indicate rejection of a request with an indication that a subsequent request may be accepted with parameter values included by the MAPC responding AP in a MAPC Request Parameter Set field. A MAPC Operation Type field set to 5 may be omitted when a MAPC Request Parameter Set field is not present for a corresponding MAPC scheme.

[0234] After two APs establish a MAPC agreement, either AP may initiate a MAPC negotiation as a MAPC requesting AP to update or tear down the MAPC agreement.

[0235] To request establishment of a new MAPC agreement, a MAPC requesting AP may set a MAPC Operation Type field to a value of zero. When the MAPC Operation Type field is set to zero, a MAPC Request Parameter Set field may be included according to scheme-specific rules for each MAPC scheme.

[0236] A MAPC requesting AP may refrain from requesting establishment of a new MAPC agreement for a specific MAPC scheme if a MAPC responding AP indicates that MAPC agreement establishment is disabledDocket No.: 25-3004PCTfor that MAPC scheme in a most recently received MAPC Discovery Request frame, MAPC Discovery Response frame, or MAPC Negotiation Request frame.

[0237] A MAPC responding AP may accept, reject, or reject with suggested alternative parameters for MAPC agreement establishment by following MAPC agreement negotiation procedures. If a MAPC responding AP accepts a request to establish a new MAPC agreement for a specific MAPC scheme, the MAPC requesting AP and the MAPC responding AP are considered to have established a MAPC agreement for that specific MAPC scheme.

[0238] A MAPC requesting AP and a MAPC responding AP may establish up to one MAPC agreement for each of Co-BF, Co-SR, and Co-TDMA, and up to one MAPC agreement per restricted target wake time (R-TWT) schedule for Co-RTWT.

[0239] A MAPC requesting AP may refrain from indicating agreement update or agreement teardown for a MAPC scheme in a MAPC Negotiation Request frame when no established MAPC agreement exists for that MAPC scheme between the MAPC requesting AP and the MAPC responding AP.

[0240] When an AP participates in MAPC negotiation to establish one or more new MAPC agreements, the AP may additionally assign an AP identifier (AP ID) to a peer AP with which the AP establishes a MAPC agreement.

[0241] An AP ID corresponds to an association identifier value. The same AP ID value may not be assigned by an AP or by an affiliated multi-link device (MLD) to any other station (STA). The same AP ID value may not be assigned by any other AP within a same multiple BSSID set to any other STA. The same AP ID value may not be assigned by any other AP MLD having any affiliated AP within the same multiple BSSID set to any other non-AP MLD

[0242] When an AP belongs to a multiple BSSID set, an assigned AP ID value may be greater than 2n, where n is a value carried in a MaxBSSID Indicator field.

[0243] To assign an AP ID to another AP, an AP may include an AP ID field in a MAPC element.

[0244] A MAPC requesting AP may omit an AP ID field in a MAPC element carried in a transmitted MAPC Negotiation Request frame unless no MAPC agreement exists between the MAPC requesting AP and the MAPC responding AP for any of Co-BF, Co-SR, or Co-TDMA and the MAPC requesting AP is requesting establishment of a new MAPC agreement for at least one of Co-BF, Co-SR, or Co-TDMA.

[0245] A MAPC responding AP may omit an AP ID field in a MAPC element carried in a transmitted MAPC Negotiation Response frame unless no MAPC agreement exists between the MAPC requesting AP and the MAPC responding AP for any of Co-BF, Co-SR, or Co-TDMA and the MAPC responding AP accepts a new MAPC agreement for at least one of Co-BF, Co-SR, or Co-TDMA.

[0246] If all MAPC agreements among Co-BF, Co-SR, and Co-TDMA between two APs cease to exist, AP IDs assigned by the MAPC requesting AP and the MAPC responding AP are no longer valid.Docket No.: 25-3004PCT

[0247] To request a parameter update for an established MAPC agreement, a MAPC requesting AP may set a MAPC Operation Type field to a value of one. When the MAPC Operation Type field is set to one, a MAPC Request Parameter Set field may be included according to scheme-specific rules.

[0248] A MAPC responding AP may accept, reject, or reject with suggested alternative parameters for an update of an existing MAPC agreement. If the MAPC responding AP rejects the update by setting the MAPC Operation Type field to a value of four or five, the agreement update procedure fails and parameters of the MAPC agreement remain unchanged.

[0249] To request teardown of an established MAPC agreement, a MAPC requesting AP may set a MAPC Operation Type field to a value of two in a MAPC Scheme Request field that carries the request. When the MAPC Operation Type field is set to two, a MAPC Request Parameter Set field may be omitted.

[0250] A MAPC responding AP may accept a request to tear down an existing MAPC agreement by following MAPC agreement negotiation procedures.

[0251] When a MAPC requesting AP tears down a last MAPC agreement among Co-BF, Co-SR, and Co-TDMA with a MAPC responding AP, mutually assigned AP IDs may be released and become available for reassignment.

Claims

Docket No.: 25-3004PCTCLAIMS1. A method comprising:transmitting, by a first access point (AP) to a second AP, a first frame comprising a request to form a multi-AP group;receiving, by the first AP from the second AP, a second frame indicating acceptance of the request;transmitting, by the first AP to the second AP, a third frame indicating a non-primary channel access (NPCA) operation schedule for the second AP, wherein the NPCA operation schedule indicates a first time period during which the second AP enables NPCA operation and a second time period during which the second AP disables NPCA operation; andreceiving, by the first AP from the second AP, a fourth frame indicating acceptance or rejection of the NPCA operation schedule.

2. A method comprising:transmitting, by a first access point (AP) to a second AP, a first frame indicating whether nonprimary channel access (NPCA) operation is enabled at the second AP.

3. The method of claim 2, wherein the first AP comprises a coordinating AP.

4. The method of any of claims 2-3, wherein the second AP comprises a coordinated AP.

5. The method of any of claims 2-4, wherein the first frame comprises a management frame or an action frame.

6. The method of any of claims 2-5, wherein the first frame comprises schedule information for NPCA operation by the second AP.

7. The method of claim 6, wherein the schedule information indicates a first time period during which the second AP enables NPCA operation.

8. The method of claim 7, wherein the schedule information further indicates a start time of the first time period.

9. The method of any of claims 7-8, wherein the schedule information further indicates an end time of the first time period.

10. The method of any of claims 7-9, further comprising disabling, by the first AP, NPCA operation during the first time period.

11. The method of any of claims 7-10, wherein the schedule information indicates a second time period during which the second AP disables NPCA operation.

12. The method of claim 11, wherein the schedule information further indicates a start time of the second time period.

13. The method of any of claims 11-12, wherein the schedule information further indicates an end time of the second time period.Docket No.: 25-3004PCT14. The method of any of claims 11-13, further comprising enabling, by the first AP, NPCA operation during the second time period.

15. The method of any of claims 2-14, wherein the first frame comprises a field that indicates whether NPCA operation is enabled at the second AP.

16. The method of any of claims 7-15, wherein the schedule information indicates a periodicity of the first time period.

17. The method of claim 16, wherein the schedule information indicates a time interval between successive first time periods during which the second AP enables NPCA operation.

18. The method of any of claims 6-17, wherein the first frame comprises an NPCA schedule information element that comprises the schedule information.

19. The method of any of claims 6-18, further comprising receiving, by the first AP from the second AP, a second frame indicating acceptance or rejection of the schedule information.

20. The method of any of claims 6-18, further comprising receiving, by the first AP from the second AP, a second frame indicating modified schedule information.

21. The method of any of claims 6-18, further comprising receiving, by the first AP from the second AP, a second frame comprising a request to modify the schedule information.

22. The method of claim 21 , wherein the request comprises modified schedule information.

23. The method of any of claims 21-22, further comprising transmitting, by the first AP to the second AP, a third frame accepting or rejecting the request.

24. The method of any of claims 6-18, further comprising transmitting, by the first AP to the second AP, a second frame indicating modified schedule information.

25. The method of any of claims 2-24, further comprising transmitting, by the first AP to the second AP, a third frame comprising a request to form a multi-AP group.

26. The method of claim 25, further comprising receiving, by the first AP from the second AP, a fourth frame indicating acceptance or rejection of the request.

27. The method of any of claims 2-24, wherein the first frame comprises a request to form a multi-AP group with the second AP.

28. The method of claim 27, further comprising receiving, by the first AP from the second AP, a third frame indicating acceptance or rejection of the request.

29. The method of claim 2, wherein the first frame comprises an initial control frame (ICF).

30. The method of claim 29, wherein the first AP obtains a transmission opportunity (TXOP) on a primary channel (PCH) after transmitting the ICF.

31. The method of any of claims 29-30, wherein the ICF comprises a duration field that indicates a first time period during which the second AP enables NPCA operation.

32. A method comprising:Docket No.: 25-3004PCTreceiving, by a first access point (AP) from a second AP, a first frame comprising a request to form a multi-AP group;transmitting, by the first AP to the second AP, a second frame indicating acceptance of the request;receiving, by the first AP from the second AP, a third frame indicating a non-primary channel access (NPCA) operation schedule for the first AP, wherein the NPCA operation schedule indicates a first time period during which the first AP enables NPCA operation and a second time period during which the first AP disables NPCA operation; andtransmitting, by the first AP to the second AP, a fourth frame indicating acceptance or rejection of the NPCA operation schedule.

33. A method comprising:receiving, by a first access point (AP) from a second AP, a first frame indicating whether nonprimary channel access (NPCA) operation is enabled at the first AP.

34. The method of claim 33, wherein the second AP comprises a coordinating AP.

35. The method of any of claims 33-34, wherein the first AP comprises a coordinated AP.

36. The method of any of claims 33-35, wherein the first frame comprises a management frame or an action frame.

37. The method of any of claims 33-36, wherein the first frame comprises schedule information for NPCA operation by the first AP.

38. The method of claim 37, wherein the schedule information indicates a first time period during which the first AP enables NPCA operation.

39. The method of claim 38, wherein the schedule information further indicates a start time of the first time period.

40. The method of any of claims 38-39, wherein the schedule information further indicates an end time of the first time period.

41. The method of any of claims 38-40, further comprising enabling, by the first AP, NPCA operation during the first time period.

42. The method of any of claims 38-41 , wherein the schedule information indicates a second time period during which the first AP disables NPCA operation.

43. The method of claim 42, wherein the schedule information further indicates a start time of the second time period.

44. The method of any of claims 42-43, wherein the schedule information further indicates an end time of the second time period.

45. The method of any of claims 42-44, further comprising disabling, by the first AP, NPCA operation during the second time period.Docket No.: 25-3004PCT46. The method of any of claims 33-45, wherein the first frame comprises a field that indicates whether NPCA operation is enabled at the first AP.

47. The method of any of claims 38-46, wherein the schedule information indicates a periodicity of the first time period.

48. The method of claim 47, wherein the schedule information indicates a time interval between successive first time periods during which the first AP enables NPCA operation.

49. The method of any of claims 37-48, wherein the first frame comprises an NPCA schedule information element that comprises the schedule information.

50. The method of any of claims 37-49, further comprising transmitting, by the first AP to the second AP, a second frame indicating acceptance or rejection of the schedule information.

51. The method of any of claims 37-50, further comprising transmitting, by the first AP to a station (STA) associated to the first AP, a third frame comprising the schedule information.

52. The method of any of claims 37-49, further comprising transmitting, by the first AP to the second AP, a second frame indicating modified schedule information.

53. The method of any of claims 37-49, further comprising transmitting, by the first AP to the second AP, a second frame comprising a request to modify the schedule information.

54. The method of claim 53, wherein the request comprises modified schedule information.

55. The method of any of claims 53-54, further comprising receiving, by the first AP from the second AP, a third frame accepting or rejecting the request.

56. The method of claim 55, further comprising transmitting, by the first AP to a station (STA) associated to the first AP, a fourth frame comprising the modified schedule information.

57. The method of any of claims 37-49, further comprising receiving, by the first AP from the second AP, a second frame indicating modified schedule information.

58. The method of claim 57, further comprising transmitting, by the first AP to a station (STA) associated to the first AP, a third frame comprising the modified schedule information.

59. The method of any of claims 33-58, further comprising receiving, by the first AP from the second AP, a fourth frame comprising a request to form a multi-AP group.

60. The method of claim 59, further comprising transmitting, by the first AP to the second AP, a fifth frame indicating acceptance or rejection of the request.

61. The method of any of claims 33-58, wherein the first frame comprises a request to form a multi-AP group with the first AP.

62. The method of claim 61 , further comprising transmitting, by the first AP to the second AP, a third frame indicating acceptance or rejection of the request.

63. The method of claim 33, wherein the first frame comprises an initial control frame (IGF).Docket No.: 25-3004PCT64. The method of claim 63, wherein the second AP obtains a transmission opportunity (TXOP) on a primary channel (PCH) after transmitting the ICF.

65. The method of any of claims 63-64, wherein the ICF comprises a duration field that indicates a first time period during which the first AP enables NPCA operation.

66. A device comprising:one or more processors; andmemory storing instructions that, when executed by the one or more processors, cause the device to perform a method according to any of claims 1-65.

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

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