WO2026006347A1

WO2026006347A1 - Dynamic subchannel operation with active peer-to-peer link

Info

Publication number: WO2026006347A1
Application number: PCT/US2025/035105
Authority: WO
Inventors: Tuncer Baykas; Jeongki Kim; Esmael Hejazi Dinan; Leonardo Alisasis LANANTE; Serhat Erkucuk; Jiayi Zhang
Original assignee: Ofinno LLC
Current assignee: Ofinno LLC
Priority date: 2024-06-28
Filing date: 2025-06-25
Publication date: 2026-01-02
Anticipated expiration: 2026-12-28

Abstract

In an aspect, an access point (AP) receives from a first station (STA) a first frame indicating a second STA with which the first STA has a direct link over a first channel. The AP transmits to the first STA a second frame requesting that the first STA switch from the first channel to a second channel. Based on the first frame, the second frame further requests that the second STA switch from the first channel to the second channel. In another aspect, a first STA receives from an AP a first frame requesting that a second STA switch to a first channel. The first STA switches to the first channel based on the first STA having a direct link with the second STA over a second channel.

Description

TITLE

Dynamic Subchannel Operation with Active Peer-to-Peer Link CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application No. 63/665,342, filed June 28,

2024, which is hereby incorporated by reference in its entirety.

BRIEF DESCRIPTION OF THE DRAWINGS

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

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

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

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

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

[0007] FIG. 5 illustrates an example common info field.

[0008] FIG. 6 illustrates an example Request-to-Send (RTS)/Clear-to-Send (CTS) procedure.

[0009] FIG. 7 is an example that illustrates a multi-user Request-to-Send (MU-RTS)/Clear-to-Send (CTS) procedure.

[0010] FIG. 8 illustrates an example MU-RTS trigger frame.

[0011] FIG. 9 illustrates an example dynamic subchannel operation (DSC) procedure.

[0012] FIG. 10 illustrates a problem that may arise using the DSC procedure illustrated in FIG. 9.

[0013] FIG. 11 illustrates a procedure according to an embodiment.

[0014] FIG. 12 illustrates another procedure according to an embodiment.

[0015] FIG. 13 illustrates another procedure according to an embodiment.

[0016] FIG. 14 illustrates another procedure according to an embodiment.

[0017] FIG. 15 illustrates another procedure according to an embodiment.

[0018] FIG. 16 illustrates an example process according to an embodiment.

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

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

DETAILED DESCRIPTION

[0021] 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 that shown. For example, the actions listed in any flowchart may be re-ordered or only optionally used in some embodiments.

[0022] 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.

[0023] 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.

[0024] If A and B are sets and every element of A is an element of B, A is called a subset of B. In this specification, only non-empty sets and subsets are considered. For example, possible subsets of B = {STA1 , STA2} are: {STA1 }, {STA2}, and {STA1 , STA2}. The phrase “based on” (or equally “based at least on”) is indicative that the phrase following the term “based on” is an example of one of a multitude of suitable possibilities that may, or may not, be employed to one or more of the various embodiments. The phrase “in response to” (or equally “in response at least to”) is indicative that the phrase following the phrase “in response to” is an example of one of a multitude of suitable possibilities that may, or may not, be 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.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] Many of the elements described in the disclosed embodiments may be implemented as modules. A module is defined here as an element that performs a defined function and has a defined interface to other elements. The modules described in this disclosure may be implemented in hardware, software in combination with hardware, firmware, wetware (e.g. hardware with a biological element) or a combination thereof, which may be behaviorally equivalent. For example, modules may be implemented as a software routine written in a computer language configured to be executed by a hardware machine (such as C, C++, Fortran, Java, Basic, Matlab or the like) or a modeling/simulation program such as Simulink, Stateflow, GNU Octave, or LabVIEWMathScript. It may be possible to implement modules using physical hardware 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.

[0029] FIG. 1 illustrates example wireless communication networks in which embodiments of the present disclosure may be implemented.

[0030] 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 infrastructure network 102 may include one or more basic service sets (BSSs) 110 and 120 and a distribution system (DS) 130.

[0031] 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.

[0032] 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 130and may have the same service set identification (SSID).

[0033] 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.

[0034] 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). [0035] For example, in FIG. 1, STAs 106-4, 106-5, and 106-6 may be configured to form a first I BSS 112- 1. Similarly, STAs 106-7 and 106-8 may be configured to form a second IBSS 112-2. Since an IBSS does not include an AP, it does not include a centralized management entity. Rather, STAs within an IBSS are managed in a distributed manner. STAs forming an IBSS may be fixed or mobile.

[0036] 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.

[0037] 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 PLOP service data unit (PSDU). For example, the PSDU may include a PHY Convergence Protocol (PLCP) 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.

[0038] A frequency band may include one or more sub-bands or frequency channels. For example, PPDUs conforming to the IEEE 802.11 n, 802.11 ac, 802.11 ax and/or 802.11 be standard amendments may be transmitted over the 2.4 GHz, 5 GHz, and/or 6 GHz bands, each of which may be divided into multiple 20 MHz channels. The PPDUs may be transmitted over a physical channel having a minimum bandwidth of 20 MHz. Larger channels may be formed through channel bonding. For example, PPDUs may be transmitted over physical channels having bandwidths of 40 MHz, 80 MHz, 160 MHz, or 520 MHz by bonding together multiple 20 MHz channels.

[0039] 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. [0040] 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.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] As shown in FIG. 3, a MAC frame includes a MAC header, a variable length frame body, and a frame check sequence (FCS).

[0045] 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.

[0046] 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.

[0047] 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.

[0048] The type and subtype subfields together identify the function of the MAC frame. There are three frame types: control, data, and management. Each of the frame types has several defined subtypes. Bits within the subtype subfield are used to indicate a specific modification of the basic data frame (subtype 0). For example, in data frames, the most significant bit (MSB) of the subtype subfield, bit 7 (B7) of the frame control field, is defined as the QoS subfield. When the QoS subfield is set to 1 , it indicates a QoS data frame, which is a data frame that contains a QoS control field in its MAC header. The second MSB of the 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.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] The power management subfield is used to indicate the power management mode of a STA.

[0053] 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.

[0054] The protected frame subfield is set to 1 if the frame body field contains information that has been processed by a cryptographic encapsulation algorithm.

[0055] The +HTC subfield indicates that the MAC frame contains an HT control field.

[0056] 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.

[0057] Up to four address fields may be present in the MAC frame format. The address fields are used to indicate the basic service set identifier (BSSID), source address (SA), destination address (DA), transmitting address (TA), and receiving address (RA). Certain frames may not contain some of the address fields. Certain address field usage may be specified by the relative position of the address field (1-4) within the MAC header, independent of the type of address present in that field. Specifically, the address 1 field always identifies the intended receiver(s) of the frame, and the address 2 field, where present, always identifies the transmitter of the frame.

[0058] 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.

[0059] 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 .

[0060] 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.

[0061] 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.

[0062] 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.

[0063] 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 be 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.

[0064] 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.

[0065] 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. [0066] 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, the Duration 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).

[0067] 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.

[0068] The Common I nfo 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.

[0069] 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/RA-RU Information subfield, an UL Target Receive Power subfield, a PS160 subfield, 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.

[0070] 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 SIFS (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.

[0071] 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.

[0072] FIG. 5 illustrates an example Common Info field 500. Common Info field 500 may be an embodiment of the Common Info field of trigger frame 400 for example. As shown in FIG. 5, Common Info field 500 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”).

[0073] FIG. 6 illustrates an example 600 of a Request-to-Send (RTS)/Clear-to-Send (CTS) procedure. Example 600 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. 6, example 600 may include STAs 602 and 604. Other STAs of the same BSS may also be within communication range of STAs 602 and 604.

[0074] In an example, STA 602 may transmit an RTS frame 606 to STA 604. STA 602 may transmit RTS frame 606 to protect from hidden STA(s) the transmission of a data frame 610 that STA 602 intends to transmit. RTS frame 606 may include a Duration/ID field. The Duration/ID field may be set to the time, in microseconds, required to transmit data frame 610, plus one CTS frame, plus one ACK frame (if required), plus three SIFS (Short Interframe Spacing) periods.

[0075] In an example, STA 604 may respond to RTS frame 606 by transmitting a CTS frame 608 to STA 602. CTS frame 608 may be transmitted one SIFS period after RTS frame 606. STA 604 may respond to RTS frame 606 when RTS frame 606 is addressed to STA 604 and after considering the NAV, unless the NAV was set by a frame originating from STA 602. STA 604 may respond to the RTS frame 606 when RTS frame 606 is addressed to STA 604 and if the NAV indicates idle. For a non-S1 G STA, the NAV indicates idle when the NAV count is 0 or when the NAV count is non-zero but a nonbandwidth signaling TA obtained from a TA field of RTS frame 606 matches a saved transmission opportunity (TXOP) holder address. For an S1 G STA, the NAV indicates idle when both the NAV and RID (response indication deferral) counters are 0 or when either the NAV or RID counter is non-zero but the TA field of RTS frame 606 matches the saved TXOP holder address.

[0076] STA 604 may set an RA field of CTS frame 608 to a nonbandwidth signaling TA obtained from the TA field of RTS frame 606. STA 604 may set a Duration field of CTS frame 608 based on the Duration/ID field of RTS frame 606, namely as equal to the value of the Duration/ID field of RTS frame 606, adjusted by subtracting the time required to transmit CTS frame 608 and one SIFS period. [0077] Upon receiving CTS frame 608, STA 602 may wait one SIFS period before transmitting data frame 610. STA 604 may transmit an ACK frame 612 in response to data frame 610. STA 604 may transmit ACK frame 612 one SIFS after receiving data frame 610.

[0078] As shown in example 600, other STAs within communication range of STAs 602 and 604, and belonging to the same BSS, may set their NAVs according to RTS frame 606 and/or CTS frame 608. For example, a STA receiving RTS frame 606 may set its NAV based on the Duration/ID field of RTS frame 606. Another STA receiving CTS frame 608 may set its NAV based on the Duration field of CTS frame 608. As such, the other STAs may not access the channel using EDCA until the end of transmission of ACK frame 612.

[0079] FIG. 7 is an example 700 that illustrates a multi-user Request-to-Send (MU-RTS)/Clear-to-Send (CTS) procedure. Example 700 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 (“IEEE P802.11-REVme™/D3.0, April 2023”). As shown in FIG. 7, example 700 may include an AP 702 and STAs 704 and 706. STAs 704 and 706 may be associated with AP 702. For the purpose of illustration, example 700 also illustrates STAs of an overlapping basic service set (OBSS) relative to the BSS of AP 702 (OBSS STAs). The OBSS STAs, as shown in FIG. 7, may be hidden from AP 702 (outside of the communication range of AP 702) or exposed to AP 702 (within the communication range of AP 702).

[0080] In example 700, AP 702 wishes to transmit a downlink (DL) multi-user (MU) PPDU 714 to STAs 704 and 706. DL MU PPDU 714 may comprise data for each of STAs 704 and 706. DL MU PPDU 714 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 704, STA 706) served by DL MU PPDU 714.

[0081] As shown in FIG. 7, to protect the transmission of DL MU PPDU 714 to STAs 704 and 706 from interference by OBSS STAs hidden from AP 702, AP 702 may use the MU-RTS/CTS procedure to initiate a TXOP and to protect the TXOP frame exchange sequence. AP 702 may initiate the TXOP by transmitting an MU-RTS trigger frame 708 that solicits simultaneous CTS frame transmissions from STAs 704 and 706.

[0082] MU-RTS trigger frame 708 may have a format as illustrated by MU-RTS trigger frame 800 illustrated in FIG. 8. As such, MU-RTS trigger frame 708 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 500 described above. The duration field may be set to the time, in microseconds, required to transmit DL MU PPDU 714, plus the time required to transmit one CTS frame, one ACK frame (if required), and three SIFS periods. [0083] The one or more user info fields correspond respectively to the one or more STAs solicited by the MU-RTS trigger frame. In example 700, MU-RTS trigger frame 708 may comprise a user info field for each of STAs 704 and 706 indicating that a CTS frame is solicited from each of STAs 704 and 706. As shown in FIG. 8, a user info field may comprise an AID12 subfield, an RU allocation subfield, reserved bits, and a PS 160 subfield. The AID12 subfield comprises an association identifier of the STA to which the user info field is addressed. The RU allocation subfield indicates a channel on which the solicited STA is to transmit the CTS frame. In an example, this may include a primary 20 MHz channel, a primary 40 MHz, a primary 80 MHz channel, a primary 160 MHz, an 80+80 Mhz channel, or a 320 MHz channel.

[0084] AP 702 may send MU-RTS trigger frame 708 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 708, AP 702 may request at least one non-AP STA to send a CTS frame that occupies that channel. In an example, AP 702 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 708.

[0085] After transmitting MU-RTS trigger frame 708, AP 702 may wait for a CTSTimeout interval of aSIFSTime + aSlotTime + aRxPHYStartDelay that begins when a MAC layer of AP 702 receives a PHYTXEND.confirm primitive for transmitted MU-RTS trigger frame 708. If the MAC layer does not receive a PHY-RXEARLYSIG.indication or a PHY-RXSTART.indication primitive during the CTSTimeout interval, AP 702 may conclude that the transmission of MU-RTS trigger frame 708 has failed, and, if MU- RTS trigger frame 708 initiated a TXOP, AP 702 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 708 was successful. The receipt of a CTS frame from any non-AP STA addressed by MU-RTS trigger frame 708 before the PHY- RXEND.indication primitive shall be interpreted as the successful transmission of MU-RTS trigger frame 708, 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 708. AP 702 may process the received frame and, if MU-RTS trigger frame 708 initiated a TXOP, AP 702 shall invoke its backoff procedure at the PHY-RXEND.indication primitive.

[0086] In example 700, on receiving MU-RTS trigger frame 708, STAs 704 and 706 respond by transmitting respectively CTS frames 710 and 712 to AP 702. In an example, STAs 704 and 706 begin the transmission of CTS frames 710 and 712, respectively, at the SIFS time boundary after an end of a received PPDU comprising MU-RTS trigger frame 708. In an example, STA 704 (or STA 706) responds to MU-RTS trigger frame 708 with a CTS frame when the following conditions are met: MU-RTS trigger frame 708 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 708 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 704 (or STA 706) does not send a CTS frame to AP 702.

[0087] In an example, STAs 704 and 706 may set an RA field of respectively CTS frames 710 and 712 to a TA obtained from the TA field of MU-RTS trigger frame 708. In an example, STAs 704 and 706 may set a duration field of respectively CTS frames 710 and 712 based on the duration field of MU-RTS trigger frame 708, namely as equal to the value of the duration field of MU-RTS trigger frame 708, adjusted by subtracting the time required to transmit respectively CTS frames 710 and 712 and one SIFS period.

[0088] OBSS STAs exposed to AP 702 may receive MU-RTS trigger frame 708 due to being within the communication range of AP 702. In an example, as shown in FIG. 7, on receiving MU-RTS trigger frame 708, OBSS STAs exposed to AP 702 set their respective NAVs based on the duration field of MU-RTS trigger frame 708. As such, the OBSS STAs exposed to AP 702 may not access the wireless medium for the duration of the TXOP initiated by AP 702.

[0089] OBSS STAs hidden from AP 702 do not receive MU-RTS trigger frame 708 due to being outside the communication range of AP 702. However, in an example, as shown in FIG. 7, some of the OBSS STAs hidden from AP 702 may receive CTS frame 710 and/or CTS frame 712 and may set their respective NAVs based on the duration field of CTS frame 710 and/or CTS frame 712. As such, some of the OBSS STAs hidden from AP 702 may also not access the wireless medium for the duration of the TXOP initiated by AP 702.

[0090] On receiving CTS frame 710 and/or CTS frame 712, AP 702 may wait one SIFS period before transmitting DL MU PPDU 714. On receiving DL MU PPDU 714, STAs 704 and 706 may respond by transmitting respective BlockAck (BA) frames 716 and 718 to AP 702.

[0091] FIG. 9 is an example 900 that illustrates a dynamic subchannel operation (DSO) procedure. DSO can enable an AP to utilize a secondary (non-primary) channel in a dynamic manner on a per-TXOP basis whenever the AP wins channel access on the secondary channel. The AP can dynamically decide whether to allocate STAs on the primary channel or the secondary channel, e.g., depending on bandwidth availability, channel conditions, and QoS requirements. For example, the AP may use DSO to align the presence of narrower bandwidth STAs on the secondary channel.

[0092] As shown in FIG. 9, example 900 includes an AP 902 and a STA 904. STA 904 may be associated with AP 902. AP 902 and STA 904 may operate on a first channel (Channel 1) or a second channel (Channel 2). It is assumed in example 900 that AP 902 and STA 904 operate on the first channel at the beginning of example 900 and that STA 904 supports DSO. That is, STA 904 is able to switch from the first channel to another supported channel (e.g., Channel 2) within a pre-defined delay. [0093] Example 900 may start with STA 904 transmitting a frame 906 to AP 902. Frame 906 may include information that STA 904 supports DSO. Frame 906 may further indicate a set of channels to which STA 904 is able to switch from the first channel. Frame 906 may further indicate a respective delay for STA 904 to switch from the first channel to each channel of the set of channels. On receiving frame 906, AP 902 may transmit to STA 904 a frame 908 acknowledging the information contained in frame 906.

[0094] Subsequently, AP 902 may obtain a TXOP 950 on the first channel and may transmit a frame 910 instructing STA 904 to switch to the second channel (Channel 2). Frame 910 may comprise a DSO initial control frame. The DSO initial control frame may be a modified version of MU-RTS frame 800 described above. AP 902 may wish that STA 904 switch to the second channel in order to free the first channel for communication with another STA (not shown in FIG. 9) or in order to communicate with STA 904 on the second channel.

[0095] On receiving frame 910 and based on STA 904 supporting DSO and being able to switch to the second channel within the pre-defined delay, STA 904 switches to the second channel and transmits a frame 912 via the second channel to AP 902. Where frame 910 is a modified MU-RTS frame, frame 912 may be a CTS frame. Frame 912 indicates to AP 902 that STA 904 switched to the second channel. After reception of frame 912 on the first channel, AP 902 may use the first channel for uplink/downlink communication with another STA (not shown in FIG. 9).

[0096] FIG. 10 is an example 1000 that illustrates a problem that may arise using the DSO procedure illustrated in FIG. 9. As shown in FIG. 10, example 1000 includes AP 902 and STA 904, described above in FIG. 9, and a STA 1002. Like AP 902 and STA 904, STA 1002 may also operate on the first channel (Channel 1) and the second channel (Channel 2).

It is assumed in example 1000 that AP 902, STA 904, and STA 1002 operate on the first channel at the beginning of example 1000. It is also assumed in example 1000 that STAs 904 and STA 1002 have a direct link over the first channel. As used herein, a direct link may comprise a peer-to-peer link between STAs. The peer-to-peer link may be established using the tunneled direct link setup (TDLS) protocol. AP 902 may not have knowledge of the direct link between STAs 904 and 1002.

[0097] At the beginning of example 1000, STAs 904 and 1002 may exchange data frames via the direct link on the first channel. For example, STA 1002 may transmit a data frame 1004 via the direct link to STA 904 and may receive a data frame 1006 from STA 904 via the direct link.

[0098] Subsequently, AP 902 may obtain a TXOP 1050 on the first channel and, having no knowledge of the direct link between STA 904 and STA 1002, transmits frame 910, described above, instructing STA 904 to switch to the second channel (Channel 2). On receiving frame 910 and based on STA 904 supporting DSO and being able to switch to the second channel within the pre-defined delay, STA 904 switches to the second channel and transmits frame 912 via the second channel to AP 902. [0099] After reception of frame 912 via the first channel, AP 902 may use the first channel for uplink/downlink communication with another STA (not shown in FIG. 10). Having remained on the first channel, STA 1002 may attempt to transmit a frame 1008 via the direct link with STA 904. However, as STA 904 switched to the second channel, STA 904 may fail to receive frame 1008 from STA 1002. The DSO procedure may thus cause the peer-to-peer communication between STAs 904 and 1002 to fail.

[0100] Embodiments of the present disclosure, as further described below, address the above-described problem. In an aspect, a first STA may transmit to an AP a frame indicating a second STA with which the first STA has a direct link over a first channel. The first frame may further indicate one or more channels to which the second STA is able to switch from the first channel within a pre-defined delay. The first STA may receive, from the AP, a second frame requesting that the first STA switch from the first channel to a second channel. Based on the one or more channels comprising the second channel, the second frame further requests that the second STA switch from the first channel to the second channel. As such, both the first STA and the second STA switch together from the first channel to the second channel, allowing peer-to-peer communication between the first STA and the second STA to continue via the second channel, without interruption.

[0101] FIG. 11 is an example 1100 that illustrates a procedure according to an embodiment. As shown in FIG. 11 , example 1100 includes AP 1102, STA 1104, and STA 1106. AP 1102 and STAs 1104 and 1106 may operate on multiple channels, including a first channel (Channel 1) and a second channel (Channel 2). The channels may have bandwidths of 20, 40, 80, 160, or 320 MHz, for example. STAs 1104 and STA 1106 may have a direct link over the first channel. As used herein, a direct link may comprise a peer-to-peer link between STAs. The peer-to-peer link may be established using the tunneled direct link setup (TDLS) protocol. STA 1104 may be associated with AP 1102. As such, AP 1102 may have knowledge of the channels on which STA 1104 is able to operate. STA 1106 may or may not be associated with AP 1102. As such, AP 1102 may or may not have knowledge of the channels on which STA 1106 is able to operate. In an embodiment, STA 1104 and/or STA 1106 supports dynamic subchannel operation (DSO) with active peer-to-peer link. Supporting DSO, as described above, may comprise the STA being able to switch from the first channel to another supported channel (e.g., Channel 2) within a pre-defined delay. Supporting DSO with active peer-to-peer link, as described herein, comprises being configured to perform the operations further described below.

[0102] As shown in FIG. 11 , example 1100 may begin with STA 1104 transmitting a frame 1120 to AP 1102. Frame 1120 may comprise a dynamic subchannel operation (DSO) information frame, DSO notification frame or a subband switch information frame. Frame 1120 may include information regarding STAs with which STA 1104 has a direct link over the first channel. For example, in example 1100, frame 1120 may indicate STA 1106 with which STA 1104 has a direct link over the first channel. In an embodiment, frame 1120 may further indicate a duration associated with the direct link. In an embodiment, the direct link is active during the duration. For example, the duration may indicate a value of timeout timer at STA 1104 associated with the direct link.

[0103] In an embodiment, frame 1120 may also include information that indicates a set of channels on which STA 1106 is able to operate and/or to which STA 1106 is able to switch from the first channel within a pre-defined delay. For example, in example 1100, frame 1112 may indicate that STA 1106 is able to operate on the first channel and the second channel and/or that STA 1106 is able to switch to the second channel from the first channel within the pre-defined delay. In an embodiment, STA 1106 may be able to switch from the first channel to each channel of the set of channels within the pre-defined delay. In an embodiment, frame 1120 may only indicate channels of the set of channels that STA 1106 can switch to from the first channel within the pre-defined delay. For example, due to a non-zero network allocation vector (NAV) value on a third channel, STA 1106 may be unable to switch to the third channel from the first channel within the pre-defined delay. Frame 1120 may thus not indicate the third channel. In an embodiment, frame 1120 may further indicate a respective delay for STA 1106 to switch from the first channel to each channel of the set of channels on which STA 1106 is able to operate.

[0104] In an embodiment, frame 1120 may indicate that STA 1106 supports DSO with active peer-to-peer link. That is, frame 1120 may indicate that STA 1106 is able to switch channels together with a STA (e.g., STA 1104) with which STA 1106 has a direct link in response to a request from an AP (e.g., AP 1102). In an embodiment, before transmitting frame 1120, STA 1104 may transmit a frame (not shown in FIG. 11) indicating that STA 1104 supports DSO with active peer-to-peer link. The frame may indicate that STA 1104 is able to transmit a frame, such as frame 1120, and to switch channels in response to a request from an AP (e.g., AP 1102).

[0105] In an embodiment, after receiving frame 1120, AP 1102 may obtain a TXOP 1150 on the first channel. Based on frame 1120 indicating that STA 1104 has a direct link with STA 1106 on the first channel, AP 1102 may determine that STA 1104 and STA 1106 must switch to a channel other than the first channel for the remaining duration of TXOP 1150 (to allow communication with a third STA (not shown in FIG. 11) via the first channel). Based on frame 1120 (and the set of channels indicated therein), AP 1102 may determine that STAs 1104 and 1106 may both operate on the second channel and/or switch to the second channel within the pre-defined delay. Accordingly, AP 1102 may transmit a frame 1130 to STA 1104 requesting that STA 1104 switch from the first channel to the second channel. Additionally, frame 1130 may further request that STA 1106 switch from the first channel to the second channel. Frame 1130 may comprise a dynamic subchannel operation (DSO) initial control frame or a subband switch control frame.

[0106] In an embodiment, STAs 1104 and 1106 may respond to frame 1130 by transmitting respectively frames 1132 and 1134 to AP 1102 via the second channel. Frames 1132 and 1134 indicate to AP 1102 that STAs 1104 and 1106 switched to the second channel. In an implementation, frame 1130 may comprise padding bits to allow sufficient time for STA 1104 and/or STA 1106 to switch to the second channel and transmit frames 1132 and 1134 respectively. After switching to the second channel, STAs 1104 and 1106 may establish a direct link via the second channel and may use the second channel for peer-to-peer communication. For example, STA 1106 may transmit a data frame 1136 via the second channel to STA 1104, and STA 1104 may respond by transmitting an acknowledgement frame 1138 via the second channel to STA 1106.

[0107] After receiving frames 1132 and 1134 indicating that STAs 1104 and 1106 switched to the second channel, AP 1102 may determine that the first channel is now free for communication with the third STA (not shown in FIG. 11 ). As such, AP 1102 may transmit a frame 1140 to the third STA via the first channel.

[0108] FIG. 12 is an example 1200 that illustrates another procedure according to an embodiment. AP 1202 and STAs 1204 and 1206 may operate on multiple channels, including a first channel (Channel 1) and a second channel (Channel 2). The channels may have bandwidths of 20, 40, 80, 160, or 320 MHz, for example. STAs 1204 and STA 1206 may have a direct link over the first channel. As used herein, a direct link may comprise a peer-to-peer link between STAs. The peer-to-peer link may be established using the tunneled direct link setup (TDLS) protocol. STA 1204 may be associated with AP 1202. As such, AP 1202 may have knowledge of the channels on which STA 1204 is able to operate. STA 1206 may or may not be associated with AP 1202. As such, AP 1202 may or may not have knowledge of the channels on which STA 1206 is able to operate. In an embodiment, STA 1204 and/or STA 1206 supports dynamic subchannel operation (DSC) with active peer-to-peer link. Supporting DSC, as described above, may comprise the STA being able to switch from the first channel to another supported channel (e.g., Channel 2) within a pre-defined delay. Supporting DSC with active peer-to-peer link, as described herein, comprises being configured to perform the operations further described below.

[0109] As shown in FIG. 12, example 1200 may begin with AP 1202 transmitting a frame 1216 to STA 1204. Frame 1216 may solicit a frame 1218 from STA 1204 Frame 1216 may comprise a broadcast frame or a unicast frame addressed to the STA 1204. Frame 1218 may be similar to frame 1120 described above with respect to FIG. 11 . Specifically, frame 1218 may include information regarding STAs with which STA 1204 has a direct link over the first channel. In an embodiment, frame 1218 may also include information that indicates a set of channels on which STA 1206 is able to operate and/or to which STA 1206 is able to switch from the first channel within a pre-defined delay. In an embodiment, frame 1218 may only indicate channels of the set of channels that STA 1206 can switch to from the first channel within the predefined delay. For example, due to a non-zero network allocation vector (NAV) value on a third channel, STA 1206 may be unable to switch to the third channel from the first channel within the pre-defined delay. Frame 1218 may thus not indicate the third channel. In an embodiment, frame 1218 may further indicate a respective delay for STA 1206 to switch from the first channel to each channel of the set of channels on which STA 1206 is able to operate. [0110] After the transmission of frame 1218 by STA 1204, the procedure illustrated in example 1200 continues with AP 1202 transmitting frame 1130 in an identical manner to the procedure illustrated in example 1100 described above. For the purpose of simplification, the description of the remainder of the procedure as described above with respect to FIG. 11 is not repeated herein and is incorporated herein by reference with respect to FIG. 12.

[0111] FIG. 13 is an example 1300 that illustrates another procedure according to an embodiment. AP 1302 and STAs 1304 and 1306 may operate on multiple channels, including a first channel (Channel 1) and a second channel (Channel 2). The channels may have bandwidths of 20, 40, 80, 160, or 320 MHz, for example. STAs 1304 and STA 1306 may have a direct link over the first channel. As used herein, a direct link may comprise a peer-to-peer link between STAs. The peer-to-peer link may be established using the tunneled direct link setup (TDLS) protocol. STA 1304 may be associated with AP 1302. As such, AP 1302 may have knowledge of the channels on which STA 1304 is able to operate. STA 1306 may or may not be associated with AP 1302. As such, AP 1302 may or may not have knowledge of the channels on which STA 1306 is able to operate. In an embodiment, STA 1304 and/or STA 1306 supports dynamic subchannel operation (DSC) with active peer-to-peer link. Supporting DSC, as described above, may comprise the STA being able to switch from the first channel to another supported channel (e.g., Channel 2) within a pre-defined delay. Supporting DSC with active peer-to-peer link, as described herein, comprises being configured to perform the operations further described below.

[0112] As shown in FIG. 13, example 1300 may begin with STA 1304 transmitting a frame 1308 to STA 1306. Frame 1308 may solicit a frame 1310, from STA 1306, that indicates a set of channels on which STA 1306 is able to operate and/or to which STA 1306 is able to switch within a pre-defined delay. Frame 1308 may comprise a dynamic subchannel operation (DSC) information frame or a subband switch information frame.

[0113] Upon receiving frame 1308, STA 1306 may transmit frame 1310 to STA 1304. Frame 1310 may comprise similar information as frame 1120 described above with respect to FIG. 11 . In an embodiment, frame 1310 may include information that indicates a set of channels on which STA 1306 is able to operate and/or to which STA 1306 is able to switch from the first channel within the pre-defined delay. In an embodiment, frame 1310 may only indicate channels of the set of channels that STA 1306 can switch to from the first channel within the pre-defined delay. For example, due to a non-zero network allocation vector (NAV) value on a third channel, STA 1306 may be unable to switch to the third channel from the first channel within the pre-defined delay. Frame 1310 may thus not indicate the third channel. In an embodiment, frame 1310 may further indicate a respective delay for STA 1306 to switch from the first channel to each channel of the set of channels on which STA 1306 is able to operate. Frame 1310 may comprise a dynamic subchannel operation (DSO) information frame or a subband switch information frame. [0114] After the transmission of frame 1310, the procedure illustrated in example 1300 continues with STA 1304 transmitting frame 1120 to AP 1302 in an identical manner to the procedure illustrated in example 1100 described above. For the purpose of simplification, the description of the remainder of the procedure as described above with respect to FIG. 11 is not repeated herein and is incorporated herein by reference with respect to FIG. 13.

[0115] FIG. 14 is an example 1400 that illustrates another procedure according to an embodiment. AP 1402 and STAs 1404 and 1406 may operate on multiple channels, including a first channel (Channel 1) and a second channel (Channel 2). The channels may have bandwidths of 20, 40, 80, 160, or 320 MHz, for example. STAs 1404 and STA 1406 may have a direct link over the first channel. As used herein, a direct link may comprise a peer-to-peer link between STAs. The peer-to-peer link may be established using the tunneled direct link setup (TDLS) protocol. STA 1404 may be associated with AP 1402. As such, AP 1402 may have knowledge of the channels on which STA 1404 is able to operate. STA 1406 may or may not be associated with AP 1402. As such, AP 1402 may or may not have knowledge of the channels on which STA 1406 is able to operate. In an embodiment, STA 1404 and/or STA 1406 supports dynamic subchannel operation (DSC) with active peer-to-peer link. Supporting DSC, as described above, may comprise the STA being able to switch from the first channel to another supported channel (e.g., Channel 2) within a pre-defined delay. Supporting DSC with active peer-to-peer link, as described herein, comprises being configured to perform the operations further described below.

[0116] As shown in FIG. 14, example 1400 may begin with STA 1404 transmitting a frame 1408 to AP 1402. Frame 1408 may comprise a dynamic subchannel operation (DSC) information frame or a subband switch information frame. Frame 1408 may include information regarding STAs with which STA 1404 has a direct link over the first channel. For example, in example 1400, frame 1408 may indicate STA 1406 with which STA 1404 has a direct link over the first channel. In an embodiment, frame 1408 may further indicate a duration associated with the direct link. In an embodiment, the direct link is active during the duration. For example, the duration may indicate a value of timeout timer at STA 1404 associated with the direct link.

[0117] On receiving frame 1408, AP 1402 may transmit a frame 1410 to one or more of the STAs indicated in frame 1408 and with which STA 1404 has a direct link on the first channel. In example 1400, AP 1402 transmits frame 1410 to STA 1406. Frame 1410 may comprise a dynamic subchannel operation (DSO) information request frame or a subband switch information request frame. In an embodiment, frame 1410 solicits information from STA 1406 regarding channels on which STA 1406 is able to operate and/or to which STA 1406 is able to switch from the first channel within a pre-defined delay.

[0118] On receiving frame 1410 from AP 1402, STA 1406 may transmit a frame 1412 to AP 1402. Frame 1412 may comprise a dynamic subchannel operation (DSO) information response frame or a subband switch information response frame. In an embodiment, frame 1412 may include information that indicates a set of channels on which STA 1406 is able to operate and/or to which STA 1406 is able to switch from the first channel within a pre-defined delay. For example, in example 1400, frame 1412 may indicate that STA 1406 is able to operate on the first channel and the second channel and/or that STA 1406 is able to switch to the second channel within the pre-defined delay. In an embodiment, STA 1406 may be able to switch from the first channel to each channel of the set of channels within the pre-defined delay. In an embodiment, frame 1412 may only indicate channels of the set of channels that STA 1406 can switch to from the first channel within the pre-defined delay. For example, due to a non-zero network allocation vector (NAV) value on a third channel, STA 1406 may be unable to switch to the third channel from the first channel within the pre-defined delay. Frame 1412 may thus not indicate the third channel. In an embodiment, frame 1412 may further indicate a respective delay for STA 1406 to switch from the first channel to each channel of the set of channels on which STA 1406 is able to operate.

[0119] In an embodiment, frame 1412 may indicate that STA 1406 supports DSO with active peer-to-peer link. That is, frame 1412 may indicate that STA 1406 is able to switch channels together with a STA (e.g., STA 1404) with which STA 1406 has a direct link in response to a request from an AP (e.g., AP 1402). In an embodiment, before transmitting frame 1412, STA 1404 may transmit a frame (not shown in FIG. 14) indicating that STA 1404 supports DSO with active peer-to-peer link. The frame may indicate that STA 1404 is able to transmit a frame, such as frame 1412, and to switch channels in response to a request from an AP (e.g., AP 1402).

[0120] After AP 1402 receives frame 1412 from STA 1406, the procedure illustrated in example 1400 continues with AP 1402 transmitting frame 1130 to STA 1404 and STA 1406, in an identical manner to the procedure illustrated in example 1100 described above. For the purpose of simplification, the description of the remainder of the procedure as described above with respect to FIG. 11 is not repeated herein and is incorporated herein by reference with respect to FIG. 14.

[0121] FIG. 15 is an example 1500 that illustrates a procedure according to an embodiment. As shown in FIG. 15, example 1500 includes AP 1502, STA 1504, and STA 1506. AP 1502 and STAs 1504 and 1506 may operate on multiple channels, including a first channel (Channel 1) and a second channel (Channel 2). The channels may have bandwidths of 20, 40, 80, 160, or 320 MHz, for example. STAs 1504 and STA 1506 may have a direct link over the first channel. As used herein, a direct link may comprise a peer-to-peer link between STAs. The peer-to-peer link may be established using the tunneled direct link setup (TDLS) protocol. STA 1504 may be associated with AP 1502. As such, AP 1502 may have knowledge of the channels on which STA 1504 is able to operate. STA 1506 may or may not be associated with AP 1502. As such, AP 1502 may or may not have knowledge of the channels on which STA 1506 is able to operate. In an embodiment, STA 1504 and/or STA 1506 supports dynamic subchannel operation (DSO) with active peer-to-peer link. Supporting DSO, as described above, may comprise the STA being able to switch from the first channel to another supported channel (e.g., Channel 2) within a pre-defined delay. Supporting DSO with active peer-to-peer link, as described herein, comprises being configured to perform the operations further described below.

[0122] In an embodiment, AP 1502 may obtain a TXOP 1550 on the first channel. AP 1102 may determine that STA 1504 must switch to a channel other than the first channel for the remaining duration of TXOP 1550 (e.g., to allow communication with a third STA (not shown in FIG. 11) via the first channel). AP 1502 may determine that STA 1504 may operate on the second channel and/or that STA 1504 is able to switch to the second channel within a pre-defined delay. Accordingly, AP 1502 may transmit a frame 1530 to STA 1504 requesting that STA 1504 switch from the first channel to the second channel. In an implementation, frame 1530 may comprise padding bits to allow sufficient time for STA 1504 to switch to the second channel. Frame 1530 may comprise a dynamic subchannel operation (DSO) initial control frame or a subband switch control frame.

[0123] In an embodiment, STA 1504 may respond to frame 1530 by transmitting a frame 1532 to AP 1502 via the second channel. Frame 1532 may indicate to AP 1502 that STA 1504 switched to the second channel.

[0124] In an embodiment, although frame 1530 is not addressed to STA 1506, STA 1506 may receive and decode frame 1530 to determine that STA 1504 is being instructed by AP 1502 to switch from the first channel to the second channel. Based on STA 1506 having a direct link with STA 1504 on the first channel, STA 1506 may determine to switch from the first channel to the second channel.

[0125] After switching to the second channel, STAs 1504 and 1506 may establish a direct link via the second channel and may use the second channel for peer-to-peer communication. For example, STA 1506 may transmit a data frame 1536 via the second channel to STA 1504, and STA 1504 may respond by transmitting an acknowledgement frame 1538 via the second channel to STA 1506.

[0126] After receiving frame 1532 indicating that STA 1504 switched to the second channel, AP 1502 may determine that the first channel is now free for communication with the third STA (not shown in FIG. 11). As such, AP 1502 may transmit a frame 1540 to the third STA via the first channel.

[0127] In an embodiment, example 1500 may further include STA 1506 transmitting to STA 1504 a frame 1520. Frame 1520 may comprise a dynamic subchannel operation (DSO) information frame or a subband switch information frame. Frame 1520 may include information that indicates a set of channels on which STA 1506 is able to operate and/or to which STA 1506 is able to switch from the first channel within a pre-defined delay. For example, in example 1500, frame 1520 may indicate that STA 1506 is able to operate on the first channel and the second channel and/or that STA 1506 is able to switch to the second channel within the pre-defined delay. In an embodiment, STA 1506 may be able to switch from the first channel to each channel of the set of channels within the pre-defined delay. In an embodiment, frame 1520 may only indicate channels of the set of channels that STA 1506 can switch to from the first channel within the pre-defined delay. For example, due to a non-zero network allocation vector (NAV) value on a third channel, STA 1506 may be unable to switch to the third channel from the first channel within the pre-defined delay. Frame 1520 may thus not indicate the third channel. In an embodiment, frame 1520 may further indicate a respective delay for STA 1506 to switch from the first channel to each channel of the set of channels on which STA 1506 is able to operate.

[0128] In an embodiment, after receiving frame 1520, STA 1504 may transmit a frame 1522 to AP 1502. Frame 1522 may comprise a dynamic subchannel operation (DSO) information frame or a subband switch information frame. Frame 1522 may include information regarding a set of channels on which both STAs 1504 and 1506 are able to operate and/or to which both STAs 1504 and 1506 are able to switch from the first channel with the pre-defined delay. STA 1504 may generate frame 1522 based on frame 1520. Frame 1520 may or may not indicate STA 1506 as a STA with which STA 1504 has a direct link.

[0129] FIG. 16 illustrates an example process 1600 according to an embodiment. Example process 1600 is provided for the purpose of illustration only and is not limiting. Example process 1600 may be performed by an AP, such as AP 1102. As shown in FIG. 16, process 1600 may include steps 1602 and 1604.

[0130] Step 1602 includes receiving, by the AP from a first STA, a first frame indicating a second STA with which the first STA has a direct link over a first channel. In an embodiment, the first STA may be associated with the AP. In an embodiment, the first frame may further indicate one or more channels on which the second STA is able to operate. In an embodiment, the second STA may be able to switch from the first channel to a channel of the one or more channels within a pre-defined delay. The first frame may further indicate a respective delay for the second STA to switch from the first channel to the channel of the one or more channels. In an embodiment, the first frame may further indicate a duration associated with the direct link. In an embodiment, the direct link is active during the duration. In an embodiment, the first frame may further indicate that the second STA supports dynamic channel switching. In an embodiment, the first frame may comprise a dynamic subchannel operation (DSO) information frame or a subband switch information frame.

[0131] In an embodiment, process 1600 may further include transmitting, by the AP to the first STA, a frame that solicits the first frame from the first STA. The frame soliciting the first frame may comprise a broadcast frame or a unicast frame addressed to the first STA.

[0132] In an embodiment, process 1600 may further include transmitting, by the AP to the second STA, a frame that solicits information from the second STA regarding the one or more channels. In an embodiment, process 1600 may further include receiving, by the AP from the second STA, the information regarding the one or more channels.

[0133] In an embodiment, before step 1602, process 1600 may further include receiving, by the AP from the first STA, a frame that indicates one or more channels to which the first STA is able to switch from the first channel within the pre-defined delay. The frame may further indicate a respective delay for the first STA to switch from the first channel to a channel of the one or more channels. In an embodiment, the frame may further indicate that the first STA supports dynamic channel switching.

[0134] In step 1604, process 1600 may include transmitting, by the AP to the first STA, a second frame requesting that the first STA switch from the first channel to a second channel. In an embodiment, based on the first frame, the second frame further requests that the second STA switch from the first channel to the second channel. In an embodiment, the second frame may further request that the second STA switch from the first channel to the second channel based on the one or more channels, indicated in the first frame, comprising the second channel. In an embodiment, the second frame may comprise a DSO initial control frame. In an embodiment, the second frame may comprise padding bits.

[0135] After step 1604, process 1600 may further include transmitting, by the AP to the first STA, a frame triggering communication between the first STA and the second STA over the second channel. In an embodiment, the frame triggering communication between the first STA and the second STA may comprise a trigger frame.

[0136] FIG. 17 illustrates an example process 1700 according to an embodiment. Example process 1700 is provided for the purpose of illustration only and is not limiting. Example process 1700 may be performed by a first STA, such as STA 1104. As shown in FIG. 17, process 1700 may include steps 1702 and 1704.

[0137] Step 1702 includes transmitting, by the first STA to an AP, a first frame indicating a second STA with which the first STA has a direct link over a first channel. In an embodiment, the first STA may be associated with the AP. In an embodiment, the first frame may further indicate one or more channels on which the second STA is able to operate. In an embodiment, the second STA may be able to switch from the first channel to a channel of the one or more channels within a pre-defined delay. The first frame may further indicate a respective delay for the second STA to switch from the first channel to the channel of the one or more channels. In an embodiment, the first frame may further indicate a duration associated with the direct link. In an embodiment, the direct link is active during the duration. In an embodiment, the first frame may further indicate that the second STA supports dynamic channel switching. In an embodiment, the first frame may comprise a dynamic subchannel operation (DSO) information frame or a subband switch information frame.

[0138] In an embodiment, process 1700 may further include receiving, by the first STA from the AP, a frame that solicits the first frame from the first STA. The frame soliciting the first frame may comprise a broadcast frame or a unicast frame addressed to the first STA. In an embodiment, process 1700 may further include transmitting, by the first STA to the AP, the first frame in response to the frame soliciting the first frame.

[0139] In an embodiment, before step 1702, process 1700 may further include transmitting, by the first STA to the second STA, a frame that solicits information regarding the one or more channels. Process 1700 may further include receiving, by the first STA from the second STA, a frame that indicates the one or more channels. The frame may further indicate a respective delay for the second STA to switch from the first channel to a channel of the one or more channels. In an embodiment, the frame may further indicate that the second STA supports dynamic channel switching.

[0140] In an embodiment, before step 1702, process 1700 may further include transmitting, by the first STA to the AP, a frame that indicates one or more channels to which the first STA is able to switch from the first channel within the pre-defined delay. The frame may further indicate a respective delay for the first STA to switch from the first channel to a channel of the one or more channels. In an embodiment, the frame may further indicate that the first STA supports dynamic channel switching.

[0141] In step 1704, process 1700 may include receiving, by the first STA from the AP, a second frame requesting that the first STA switch from the first channel to a second channel. In an embodiment, based on the first frame, the second frame further requests that the second STA switch from the first channel to the second channel. In an embodiment, the second frame may further request that the second STA switch from the first channel to the second channel based on the one or more channels, indicated in the first frame, comprising the second channel. In an embodiment, the second frame may comprise a DSO initial control frame. In an embodiment, the second frame may comprise padding bits.

[0142] After step 1704, process 1700 may further include receiving, by the first STA from the AP, a frame triggering communication between the first STA and the second STA over the second channel. In an embodiment, the frame triggering communication between the first STA and the second STA may comprise a trigger frame.

[0143] FIG. 18 illustrates an example process 1800 according to an embodiment. Example process 1800 is provided for the purpose of illustration only and is not limiting. Example process 1800 may be performed by a first STA, such as STA 1506. As shown in FIG. 18, process 1800 may include steps 1802 and 1804.

[0144] Step 1802 includes receiving, by the first STA from an AP, a first frame requesting that a second STA switch from a first channel to a second channel. In an embodiment, the first frame may comprise a DSO initial control frame or a subband switch control frame. In an embodiment, the first frame may comprise padding bits.

[0145] Step 1804 includes switching, by the first STA, from the first channel to the second channel based on the first STA having a direct link with the second STA over the first channel.

[0146] In an embodiment, before step 1802, process 1800 may further include transmitting, by the first STA to the second STA, a second frame that indicates one or more channels on which the first STA is able to operate. In an embodiment, the first STA may be able to switch from the first channel to a channel of the one or more channels within a pre-defined delay. The second frame may further indicate a respective delay for the first STA to switch from the first channel to the channel of the one or more channels. In an embodiment, the second frame may further indicate that the second STA supports dynamic channel switching. In an embodiment, the second frame may comprise a dynamic subchannel operation (DSO) information frame or a subband switch information frame.

[0147] In an embodiment, step 1804 may further switching, by the first STA, from the first channel to the second channel further based on the one or more channels comprising the second channel.

Claims

1. A method, comprising: receiving, by an access point (AP) from a first station (STA) via a first channel, a first frame indicating: a second STA with which the first STA has a direct link over the first channel; and one or more second channels on which the second STA is able to operate; and transmitting, by the AP to the first STA via the first channel, a second frame requesting that the first STA switch from the first channel to a third channel, wherein, based on the one or more second channels comprising the third channel, the second frame further requests that the second STA switch to the third channel.

2. A method, comprising: receiving, by an access point (AP) from a first station (STA), a first frame indicating a second STA with which the first STA has a direct link over a first channel; and transmitting, by the AP to the first STA, a second frame requesting that the first STA switch from the first channel to a second channel, wherein, based on the first frame, the second frame further requests that the second STA switch from the first channel to the second channel.

3. The method of claim 2, wherein the first frame further indicates one or more channels on which the second STA is able to operate.

4. The method of claim 3, wherein the second frame further requests that the second STA switch from the first channel to the second channel based on the one or more channels comprising the second channel.

5. The method of any of claims 3-4, wherein the second STA is able to switch from the first channel to a third channel of the one or more channels within a pre-defined delay.

6. The method of claim 5, wherein the first frame further indicates a respective delay for the second STA to switch from the first channel to the third channel.

7. The method of any of claims 2-6, wherein the first frame further indicates a duration associated with the direct link.

8. The method of claim 7, wherein the direct link is active during the duration.

9. The method of any of claims 2-8, wherein the first frame further indicates that the second STA supports dynamic channel switching.

10. The method of claim 3, further comprising transmitting, by the AP to the second STA, a third frame requesting a status of the one or more channels.

11 . The method of claim 10, further comprising receiving, by the AP from the second STA, a fourth frame indicating the status of the one or more channels.

12. The method of claim 3, further comprising transmitting, by the AP to the first STA, a fifth frame requesting a status of the one or more channels.

13. The method of claim 12, further comprising receiving, by the AP from the first STA, a sixth frame indicating the status of the one or more channels.

14. The method of any of claims 2-13, wherein the first frame comprises a dynamic subchannel operation (DSO) information frame a subband switch information frame.

15. The method of any of claims 2-14, wherein the second frame comprises a multi-user request to send (MU-RTS) frame or a trigger frame.

16. The method of any of claims 2-15, wherein the second frame comprises padding bits.

17. The method of any of claims 2-15, wherein the second frame comprise a dynamic subchannel operation (DSO) initial control frame.

18. The method of any of claims 2-17, further comprising transmitting, by the AP to the first STA, a seventh frame triggering communication between the first STA and the second STA over the second channel.

19. The method of claim 18, wherein the seventh frame comprises a trigger frame.

20. The method of any of claims 2-19, further comprising transmitting, by the AP to the first STA, an eighth frame soliciting the first frame from the first STA.

21 . The method of claim 20, wherein the eighth frame comprises a broadcast frame or a unicast frame addressed to the first STA.

22. The method of any of claims 2-21 , further comprising transmitting, by the AP via the second channel, a ninth frame that initiates a transmission opportunity (TXOP) in the second channel.

23. The method of claim 22, wherein transmitting the ninth frame comprises transmitting the ninth frame before transmitting the second frame.

24. The method of any of claims 2-23, wherein the first STA is associated with the AP.

25. The method of any of claims 2-24, further comprising receiving, by the AP from the first STA, a tenth frame that indicates one or more channels on which the first STA is able to switch from the first channel.

26. The method of claim 25, wherein the first STA is able to switch from the first channel to a fourth channel of the one or more channels within a pre-defined delay.

27. The method of claim 26, wherein the tenth frame further indicates a respective delay for the first STA to switch from the first channel to the fourth channel.

28. The method of any of claims 25-27, wherein the tenth frame further indicates that the first STA supports dynamic channel switching.

29. A method, comprising: transmitting, by a first station (STA) to an access point (AP), a frame indicating: a second STA with which the first STA has a direct link over a first channel; and one or more channels to which the second STA is able to switch from the first channel within a pre-defined delay; and receiving, by the first STA from the AP, a second frame requesting that the first STA switch from the first channel to a second channel, wherein based on the one or more channels comprising the second channel, the second frame further requests that the second STA switch from the first channel to the second channel.

30. A method, comprising: transmitting, by a first station (STA) to an access point (AP), a first frame indicating a second STA with which the first STA has a direct link over a first channel; and receiving, by first STA from the AP, a second frame requesting that the first STA switch from the first channel to a second channel, wherein, based on the first frame, the second frame further requests that the second STA switch from the first channel to the second channel.

31 . The method of claim 30, wherein the first frame further indicates one or more channels on which the second STA is able to operate.

32. The method of claim 31 , wherein the second frame further requests that the second STA switch from the first channel to the second channel based on the one or more channels comprising the second channel.

33. The method of any of claims 31-32, wherein the second STA is able to switch from the first channel to a third channel of the one or more channels within a pre-defined delay.

34. The method of claim 33, wherein the first frame further indicates a respective delay for the second STA to switch from the first channel to the third channel.

35. The method of any of claims 30-31 , wherein the first frame indicates a duration associated with the direct link.

36. The method of claim 35, wherein the direct link is active during the duration.

37. The method of any of claims 30-36, wherein the first frame further indicates that the second STA supports dynamic channel switching.

38. The method of any of claims 31-37, further comprising transmitting, by the first STA to the second STA, a third frame requesting the one or more channels.

39. The method of any of claims 31-38, further comprising receiving, by the first STA from the second STA, a fourth frame by indicating the one or more channels.

40. The method of any of claims 31-39, further comprising receiving, by the first STA from the first AP, a fifth frame requesting a status of the one or more channels.

41 . The method of claim 40, further comprising transmitting, by the first STA to the first AP, a sixth frame indicating the status of the one or more channels.

42. The method of any of claims 30-41 , wherein the first frame comprises a dynamic subchannel operation (DSO) information frame or subband switch information frame.

43. The method of any of claims 30-42, wherein the second frame comprise a DSO initial control frame or a subband switch control frame.

44. The method of any of claims 30-43, further comprising receiving, by the first STA from the first AP, a seventh frame triggering communication between the first STA and the second STA in the second channel.

45. The method of claim 44, wherein the seventh frame comprises a trigger frame.

46. The method of any of claims 30-45, further comprising receiving, by the STA from the AP, an eighth frame soliciting the first frame from the first STA.

47. The method of claim 46, wherein the eighth frame is a broadcast frame or a unicast frame addressed to the first STA.

48. The method of any of claims 30-47, further comprising receiving, by the STA via the second channel, a ninth frame that initiates a transmission opportunity (TXOP) in the second channel.

49. The method of claim 48, wherein receiving the ninth frame comprises receiving the ninth frame before receiving the second frame.

50. The method of any of claims 30-49, wherein the first STA is associated with the AP.

51 . The method of any of claims 30-50, further comprising transmitting, by the first STA to the AP, a tenth frame that indicates one or more channels on which the first STA is able to switch from the first channel.

52. The method of claim 51 , wherein the first STA is able to switch from the first channel to a fourth channel of the one or more channels within a pre-defined delay.

53. The method of claim 52, wherein the tenth frame further indicates a respective delay for the first STA to switch from the first channel to the fourth channel.

54. The method of any of claims 51-53, wherein the tenth frame further indicates that the first STA supports dynamic channel switching.

55. A method, comprising: transmitting, by a first station (STA) to a second STA, a first frame indicating one or more channels on which the first STA is able to operate; receiving, by the first STA from an access point (AP), a second frame requesting that the second STA switch to a first channel; and switching, by the first STA, to the first channel based on: the one or more channels comprising the first channel; and the first STA having a direct link with the second STA over a second channel.

56. A method, comprising: receiving, by a first station (STA) from an access point (AP), a first frame requesting that a second STA switch to a first channel; and switching, by the first STA, to the first channel based on the first STA having a direct link with the second STA over a second channel.

57. The method of claim 56, further comprising transmitting, by the first STA to the second STA, a second frame indicating one or more channels on which the first STA is able to operate.

58. The method of claim 57, wherein switching, by the first STA, to the first channel is further based on the one or more channels comprising the first channel.

59. The method of any of claims 56-58, wherein the first frame comprises a dynamic subchannel operation (DSO) initial control frame or a subband switch control frame.

60. The method of any of claims 56-59, wherein the second frame comprises a DSO information frame.

61. A device comprising: one or more processors; and memory storing instructions that, when executed by the one or more processors, cause the device to perform a method according to any of claims 1-60.

62. 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 1-60.